JP2004013049A - Toner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize oilless fixing that prevents offsetting while maintaining higher OHP translucency, by enabling small grain size particles to be pulverized, sharpening distribution on a coarse particle side, and obtaining high picture quality in a tandem transfer process as well as high transfer efficiency through prevention of skipping, scattering and reversing during transfer. <P>SOLUTION: The toner is composed in such manners that the volume mean grain size of the toner including at least a binding resin, a coloring matter and a wax is 3.5-5.5 μm, that the contents of 5.04 μm or below in the count distribution is 60 count % or higher while those of 3.17 μm or below is 5-35 count %, and that the toner particles having a grain size of 6.35-10.1 μm are contained at 35 volume % or below in the particle size distribution. In addition, the toner is composed so that an inorganic fine powder having the mean grain size of 6 nm-120 nm is externally added at 2.5-5.3 pts. wt. relative to 100 pts. wt. of the toner host particle. <P>COPYRIGHT: (C)2004,JPO

Description

【０１３４】
３価以上のアルコール成分としては、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−ソルビタン、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、１，２，４−ブタントリオール、１，２，５−ペンタントリオール、グリセロール、２−メチルプロパントリオール、２−メチル−１，２，４−ブタントリオール、トリメチロールエタン、トリメチロールプロパン、１，３，５−トリヒドロキシメチルベンゼン等が挙げられる。
【０１３５】
重合は公知の重縮合、溶液重縮合等を用いることが出来る。これによって耐塩ビマット性やカラートナーの色材の色を損なうことなしに、良好なトナーを得ることができる。
【０１３６】
多価カルボン酸と多価アルコールの使用割合は通常、カルボキシル基数に対する水酸基数の割合（ＯＨ／ＣＯＯＨ）で０．８〜１．４が一般的である。
【０１３７】
樹脂、ワックス及びトナーの分子量は、数種の単分散ポリスチレンを標準サンプルとするゲル浸透クロマトグラフィー（ＧＰＣ）によって測定された値である。
【０１３８】
装置は、東ソー社製ＨＰＬＣ８１２０シリーズ、カラムはＴＳＫｇｅｌｓｕｐｅｒＨＭ−ＨＨ４０００／Ｈ３０００／Ｈ２０００（７．８ｍｍ径、１５０ｍｍ×３）、溶離液ＴＨＦ（テトラヒドロフラン）、流量０．６ｍｌ／ｍｉｎ、試料濃度０．１％、注入量２０μＬ、検出器ＲＩ、測定温度４０℃、測定前処理は試料をＴＨＦに溶解後０．４５μｍのフィルターでろ過しシリカ等の添加剤を除去した樹脂成分を測定する。測定条件は、対象試料の分子量分布が、数種の単分散ポリスチレン標準試料により得られる検量線における分子量の対数とカウント数が直線となる範囲内に包含される条件である。
【０１３９】
また、結着樹脂の軟化点は、島津製作所のフローテスタ（ＣＦＴ５００）により、１ｃｍ^３の試料を昇温速度６℃／分で加熱しながらプランジャーにより約９．８×１０^５Ｎ／ｍ^２の荷重を与え、直径１ｍｍ、長さ１ｍｍのダイから押し出して、このプランジャーのピストンストロークと温度との関係における昇温温度特性との関係から、ピストンストロークが立ち上がり始める温度が流出開始温度（Ｔｆｂ）、曲線の最低値と流出終了点の差の１／２を求め、それと曲線の最低値を加えた点の位置における温度を１／２法における溶融温度（軟化点Ｔｍ）となる。
【０１４０】
また樹脂のガラス転移点は示差走査熱量計を用い、１００℃まで昇温し、その温度にて３分間放置した後、降温速度１０Ｋ／ｍｉｎで室温まで冷却したサンプルを、昇温速度１０Ｋ／ｍｉｎで昇温して熱履歴を測定した際に、ガラス転移点以下のベースラインの延長線とピークの立ち上がり部分からピークの頂点までの間での最大傾斜を示す接線との交点の温度を言う。
【０１４１】
ＤＳＣによる吸熱ピークの融点は、島津製作所の示差熱量分析計ＤＳＣ−５０を使用した。５Ｋ／ｍｉｎで２００℃まで昇温し、５分間保温１０℃まで急冷後、１５分間放置後５Ｋ／ｍｉｎで昇温させ、吸熱（融解）ピークから求めた。セルに投入するサンプル量は１０ｍｇ±２ｍｇとした。
【０１４２】
本形態に好適に使用される結着樹脂は、各種ビニル系モノマーによる単独重合体または共重合体も好適に使用できる。例えば、スチレン、Ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、ｐ―エチルスチレン、２，４−ジメチルアスチレン、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−ヘキシルスチレン、Ｐ−クロルスチレンなどのスチレンのおよびその誘導体があげられ、とくにスチレンが好ましい。
【０１４３】
またアクリル単量体としては、アクリル酸、メタクリル酸、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸−２−エチルヘキシル、アクリル酸シクロヘキシル、アクリル酸フェニル、メタクリル酸メチル、メタクリル酸ヘキシル、メタクリル酸−２−エチルヘキシル、β−ヒドロキシアクリル酸エチル、γ−ヒドロキシアクリル酸プロピルα−ヒドロキシアクリル酸ブチル、β−ヒドロキシメタクリル酸エチル、γ−アミノアクリル酸プロピル、γ−Ｎ，Ｎ−ジエチルアミノアクリル酸プロピル、エチレングリコールジメタクリル酸エステル、テトラエチレングリコールジメタクリル酸エステル等を挙げることができる。本発明の目的に好適なスチレンーアクリル系共重合体としては、スチレン／ブチルアクリレート共重合体であり、特にスチレンを７５〜８５重量％、ブチルアクリレートを１５〜２５重量％含有するものが好適に使用される。
【０１４４】
重合体の製造方法としては、バルク重合、塊状重合、溶液重合、懸濁重合、乳化重合などの公知の重合法を使用することができる。重合率３０〜９０重量％までバルク重合を行いついで溶剤と重合開始剤を添加して、溶液重合により反応を継続する方法等も好ましい。
【０１４５】
実施の形態３：電荷制御剤
本形態ではトナーの電荷制御の目的、及びオイルレス定着をより強固なものとするために、電荷制御剤が添加される。好ましい材料としては、アクリルスルホン酸系の重合体で、スチレン系モノマーと極性基としてスルホン酸基を有するアクリル酸系モノマーとのビニル共重合体が好ましい。特にはアクリルアミド−２−メチルプロパンスルホン酸との共重合体が好ましい特性を発揮できる。
【０１４６】
また、好ましい材料としては（化２）に示すサリチル酸誘導体の金属塩が用いられる。
【０１４７】
【化２】

【０１４８】
また、好ましい材料としては（化３）に示すベンジル酸誘導体の金属塩が用いられる。
【０１４９】
【化３】

【０１５０】
この構成により、オイルレス定着において広範囲の非オフセット温度域を確保できると共に、定着時での帯電作用による画像乱れを防止できる。これはワックスのもつ酸価を有する官能基と金属塩の帯電極性の効果と思われる。また連続使用時での帯電量の低下を防止できる。現像でのブレード融着を抑えられる。
【０１５１】
添加量は結着樹脂１００重量部に対し、０．５〜５重量部が好ましい。より好ましくは１〜４重量部、さらに好ましくは３〜４重量部である。０．５重量部よりも少ないと、帯電作用効果が無くなる。５重量部よりも多くなるとカラー画像での色濁りが目立ってくる。
【０１５２】
また、本形態に使用される顔料としては、カーボンブラック、鉄黒、グラファイト、ニグロシン、アゾ染料の金属錯体、Ｃ．Ｉ．ピグメント・イエロー１，３，７４，９７，９８等のアセト酢酸アリールアミド系モノアゾ黄色顔料、Ｃ．Ｉ．ピグメント・イエロー１２，１３，１４，１７等のアセト酢酸アリールアミド系ジスアゾ黄色顔料、Ｃ．Ｉ．ソルベントイエロー１９，７７，７９、Ｃ．Ｉ．ディスパース・イエロー１６４、Ｃ．Ｉ．ピグメント・レッド４８，４９：１，５３：１，５７，５７：１，８１，１２２，５等の赤色顔料、Ｃ．Ｉ．ソルベント・レッド４９，５２，５８，８等の赤色染料、Ｃ．Ｉ．ピグネント・ブルー１５：３等のフタロシアニン及びその誘導体の青色染顔料が１種又は２種類以上で配合される。添加量は結着樹脂１００重量部に対し、３〜８重量部が好ましい。
【０１５３】
また本形態では外添剤として、シリカ、アルミナ、酸化チタン、ジルコニア、マグネシア、フェライト、マグネタイト等の金属酸化物微粉末、チタン酸バリウム、チタン酸カルシウム、チタン酸ストロンチウム等のチタン酸塩、ジルコン酸バリウム、ジルコン酸カルシウム、ジルコン酸ストロンチウム等のジルコン酸塩あるいはこれらの混合物が用いられる。外添剤は必要に応じて疎水化処理される。
【０１５４】
シリカに処理されるシリコーンオイル系の材料としては、（化４）に示されるものが好ましい。
【０１５５】
【化４】

【０１５６】
例えばジメチルシリコーンオイル、メチルハイドロジェンシリコーンオイル、メチルフェニルシリコーンオイル、環状ジメチルシリコーンオイル、エポキシ変性シリコーンオイル、カルボキシル変性シリコーンオイル、カルビノール変性シリコーンオイル、メタクリル変性シリコーンオイル、メルカプト変性シリコーンオイル、ポリエーテル変性シリコーンオイル、メチルスチリル変性シリコーンオイル、アルキル変性シリコーンオイル、フッ素変性シリコーンオイル、アミノ変性シリコーンオイル、クロルフェニル変成シリコーンオイルのうちの少なくとも１種類以上で処理されるシリカが好適に使用される。例えば東レダウコーニングシリコーン社のＳＨ２００、ＳＨ５１０、ＳＦ２３０、ＳＨ２０３、ＢＹ１６―８２３、ＢＹ１６―８５５Ｂ等が挙げられる。処理は無機微粉末とシリコーンオイル等の材料とをヘンシェルミキサ等の混合機により混合する方法や、シリカへシリコーンオイル系の材料を噴霧する方法、溶剤にシリコーンオイル系の材料を溶解或いは分散させた後、シリカ微粉末と混合した後、溶剤を除去して作成する方法等がある。無機微粉末１００重量部に対して、シリコーンオイル系の材料は０．１〜１０重量部配合されるのが好ましい。
【０１５７】
シランカップリング剤としては、ジメチルジクロロシラン、トリメチルクロルシラン、アリルジメチルクロルシラン、ヘキサメチルジシラザン、アリルフェニルジクロルシラン、ベンジルメチルクロルシラン、ビニルトリエトキシシラン、γ−メタクリルオキシプロピルトリメトキシシラン、ビニルトリアセトキシシラン、ジビニルクロルシラン、ジメチルビニルクロルシラン等がある。シランカップリング剤処理は、微粉体を攪拌等によりクラウド状としたものに気化したシランカップリング剤を反応させる乾式処理又は、微粉体を溶媒中に分散させたシランカップリング剤を滴下反応させる湿式法等により処理される。
【０１５８】
またシランカップリング処理した後にシリコーンオイル系の材料を処理することも好ましい。
【０１５９】
正極帯電性を有する無機微粉末はアミノシランや（化５）に示されるアミノ変性シリコーンオイル、エポキシ変性シリコーンオイルで処理される。
【０１６０】
【化５】

【０１６１】
さらに疎水性処理を高めるため、ヘキサメチルジシラザンやジメチルジクロロシラン、他のシリコーンオイルによる処理の併用も好ましい。例えば、ジメチルシリコーンオイル、メチルフェニルシリコーンオイル、アルキル変性シリコーンオイルのうちの少なくとも１種類以上で処理することが好ましい。
【０１６２】
さらには、脂肪酸エステル、脂肪酸アミド、脂肪酸金属塩により処理された無機微粉末の使用も好ましい。いずれか１種または２種以上を表面処理したシリカ又は酸化チタン微粉末がより好ましい。
【０１６３】
無機微粉末を表面処理する脂肪酸、脂肪酸金属塩としては、カプリル酸、カプリン酸、ウンデシル酸、ラウリル酸、ミスチリン酸、パリミチン酸、ステアリン酸、ベヘン酸、モンタン酸、ラクセル酸、オレイン酸、エルカ酸、ソルビン酸、リノール酸等が挙げられる。中でも炭素数１５〜２０の脂肪酸が好ましい。
【０１６４】
また脂肪酸金属塩を構成する金属としては、アルミニウム、亜鉛、カルシウム、マグネシウム、リチウム、ナトリウム、鉛、バリウムが挙げられ、中でもアルミニウム、亜鉛、ナトリウムが好ましい。特に好ましくはジステアリン酸アルミニウム（Ａｌ（ＯＨ）（Ｃ_１７Ｈ_３５ＣＯＯ）_２）、またはモノステアリン酸アルミニウム（Ａｌ（ＯＨ）_２（Ｃ_１７Ｈ_３５ＣＯＯ））、等のジ脂肪酸アルミニウム、モノ脂肪酸アルミニウムが好ましい。ＯＨ基を有することが過帯電を防止し、転写不良を抑えることができる。また処理時にシリカ等の無機微粉末との処理性が向上するものと考えられる。
【０１６５】
表面処理は前記した脂肪酸を芳香族系の溶剤に溶解し、それとシリカ、酸化チタン、アルミナ等の微粉末と湿式混合または噴霧して攪拌処理し、微粉末の表面に脂肪酸を付着又は反応させて、表面処理を施し、その後に乾燥、脱溶剤処理を行うことにより生成される。このときの処理量は無機微粉末母体１００重量部に対して０．１〜２５重量部が好ましい。０．１より少ないと、処理剤の機能が十分に発揮されない。２５よりも多いと浮遊脂肪酸が多くなり、現像性や耐久性に悪影響を与える。
【０１６６】
またより好ましい形態としては、処理される無機微粉末の表面をカツプリング剤及び／又はシリコ−ンオイルにて処理を施した後に、脂肪酸及び／又は脂肪酸金属塩により処理を施すことが好ましい。単に親水性シリカの脂肪酸を処理する場合よりも均一な処理が可能となり、トナーの高帯電化を図れることと、トナーに添加したときの流動性が向上する効果があるためである。またカップリング剤及び／又はシリコ−ンオイルとともに、脂肪酸及び／又は脂肪酸金属塩を処理する構成でもかまわず、上記効果を奏する。
【０１６７】
また、後述する微細な粒子の粒度分布を有するトナー母体に対して、外添処方の構成を特定とすることにより、トナー粒子のハンドリング性を向上でき、微細粒子に起因する現像、転写において高画質化と転写性向上の両立を図ることができる。現像においては潜像をより忠実に再現できる。そして転写の際には、微細トナー粒子を、転写率を悪化させることなく転写できる。またタンデム転写においても再転写を防止でき、中抜けの発生の抑制が可能となる。さらには現像量を少なくしても高画像濃度を得ることができる。トナーが微細化されているため粒子が密になるためと考えられる。
【０１６８】
平均粒子径６ｎｍ〜１２０ｎｍである無機微粉末をトナー母体粒子１００重量部に対し２．５〜５．３重量部外添処理する構成が好ましい。平均粒子径６ｎｍよりも小さいと、シリカ浮遊や感光体へのフィルミングが生じ易い。転写時の逆転写の発生を抑え切れない。１２０ｎｍよりも大きくなると、トナーの流動性が悪化する。２．５重量部よりも少ないとトナーの流動性が悪化する。転写時の逆転写の発生を抑え切れない。５．３重量部よりも多いとシリカ浮遊や感光体へのフィルミングが生じ易い。
【０１６９】
さらには、平均粒子径が６ｎｍ〜２０ｎｍである無機微粉末をトナー母体粒子１００重量部に対し１．０〜２．５重量部と、３０ｎｍ〜１２０ｎｍである無機微粉末をトナー母体粒子１００重量部に対し１．５〜２．８重量部とを少なくとも外添処理する構成が好ましい。この構成により機能分離したシリカの使用で、現像でのハンドリング性、転写時の逆転写、中抜け、飛び散りに対しよりマージンが取れる。範囲が外れることで、そのマージン幅が狭まり、マシンサイドでの精度向上が要求されることになる。
【０１７０】
さらには、平均粒子径が６ｎｍ〜２０ｎｍ、強熱減量が０．５〜２５ｗｔ％である無機微粉末をトナー母体粒子１００重量部に対し１．０〜２．５重量部と、平均粒子径が３０ｎｍ〜１２０ｎｍで強熱減量が０．１〜２３ｗｔ％である無機微粉末をトナー母体粒子１００重量部に対し１．５〜２．８重量部とを、少なくとも外添処理する構成が好ましい。
【０１７１】
シリカの強熱減量を特定することにより現像でのハンドリング性、転写時の逆転写、中抜け、飛び散りに対しよりマージンが取れる。範囲が外れることで、そのマージン幅が狭まり、マシンサイドでの精度向上が要求されることになる。特に転写時の離型作用を安定化でき、逆転写、中抜けに対する転写マージンを安定化できる。
【０１７２】
平均粒子径が６ｎｍ〜２０ｎｍの強熱減量が０．５ｗｔ％よりも少ないと、逆転写、中抜けに対する転写マージンが狭くなる。２５ｗｔ％よりも多くなると、表面処理がムラになり、帯電のバラツキが生じる。好ましくは強熱減量が１．５〜２０ｗｔ％、より好ましくは５〜１９ｗｔ％である。
【０１７３】
平均粒子径が３０ｎｍ〜１２０ｎｍの強熱減量が０．１ｗｔ％よりも少ないと、逆転写、中抜けに対する転写マージンが狭くなる。２３ｗｔ％よりも多くなると、表面処理がムラになり、帯電のバラツキが生じる。好ましくは強熱減量が１．５〜１８ｗｔ％、より好ましくは５〜１６ｗｔ％である。
【０１７４】
さらには、平均粒子径６ｎｍ〜１２０ｎｍ強熱減量が０．５〜２５ｗｔ％である負帯電性無機微粉末をトナー母体粒子１００重量部に対し１．８〜４重量部と、平均粒子径６ｎｍ〜１２０ｎｍ、強熱減量が０．５〜２５ｗｔ％である正帯電性無機微粉末をトナー母体粒子１００重量部に対し０．５〜１．５重量部とを少なくとも外添処理する構成が好ましい。
【０１７５】
正帯電性無機微粉末を添加する効果は、トナーがライフ等により過帯電になることを抑え、より現像剤寿命を延ばすことが可能となる。さらには過帯電による転写時の飛び散りを抑える効果も得られる。０．５重量部よりも少ないとその効果が得にくい。１．５重量部よりも多くなると、現像でのかぶりが増大する。強熱減量は好ましくは１．５〜２０ｗｔ％、より好ましくは５〜１９ｗｔ％である。
【０１７６】
さらには、平均粒子径が６ｎｍ〜２０ｎｍ、強熱減量が０．５〜２５ｗｔ％である負帯電性無機微粉末をトナー母体粒子１００重量部に対し０．８〜２重量部と、平均粒子径が３０ｎｍ〜１２０ｎｍで強熱減量が０．１〜２３ｗｔ％である負帯電性無機微粉末をトナー母体粒子１００重量部に対し１．２〜２．０重量部と、平均粒子径が６ｎｍ〜２０ｎｍ強熱減量が０．５〜２５ｗｔ％である正帯電性無機微粉末をトナー母体粒子１００重量部に対し０．５〜１．５重量部とを少なくとも外添処理する構成が好ましい。
【０１７７】
この構成により機能分離した負帯電性無機微粉末、例えばシリカの使用で、現像でのハンドリング性、転写時の逆転写、中抜け、飛び散りに対しよりマージンが取れる。範囲が外れることで、そのマージン幅が狭まり、マシンサイドでの精度向上が要求されることになる。さらに６ｎｍ〜２０ｎｍの正帯電性無機微粉末を添加することにより、トナーがライフ等により過帯電になることを抑え、より現像剤寿命を延ばすことが可能となる。さらには過帯電による転写時の飛び散りを抑える効果も得られる。現像でのハンドリング性が安定する。ライフでの寿命安定化に効果がある。６ｎｍ〜２０ｎｍの無機微粉末の強熱減量は、１．５〜２０ｗｔ％、より好ましくは５〜１９ｗｔ％である。３０ｎｍ〜１２０ｎｍの無機微粉末の強熱減量は、好ましくは１．５〜１８ｗｔ％、より好ましくは５〜１６ｗｔ％である。
【０１７８】
さらには、平均粒子径が６ｎｍ〜２０ｎｍ、強熱減量が０．５〜２５ｗｔ％である負帯電性無機微粉末をトナー母体粒子１００重量部に対し０．８〜２重量部と、平均粒子径が３０ｎｍ〜１２０ｎｍで強熱減量が０．１〜２３ｗｔ％である負帯電性無機微粉末をトナー母体粒子１００重量部に対し１．２〜２．０重量部と、平均粒子径が３０ｎｍ〜１２０ｎｍで強熱減量が０．１〜２３ｗｔ％である正帯電性無機微粉末をトナー母体粒子１００重量部に対し０．５〜１．５重量部とを外添処理を外添処理する構成が好ましい。３０ｎｍ〜１２０ｎｍの正帯電性無機微粉末の使用により、ライフでの寿命安定化と、転写での中抜け、逆転写の防止の両立に効果が得られる。６ｎｍ〜２０ｎｍの無機微粉末の強熱減量は、１．５〜２０ｗｔ％、より好ましくは５〜１９ｗｔ％である。３０ｎｍ〜１２０ｎｍの無機微粉末の強熱減量は、好ましくは１．５〜１８ｗｔ％、より好ましくは５〜１６ｗｔ％である。
【０１７９】
乾燥減量（％）は、予め乾燥、放冷、精秤した容器に試料約１ｇを取り、精秤する。熱風乾燥器（１０５℃±１℃）で２時間乾燥する。デシケータ中で３０分間放冷後その重量を精秤し次式より算出する。
【０１８０】
乾燥減量（％）＝乾燥による減量（ｇ）／試料量（ｇ）×１００
強熱減量は、予め乾燥、放冷、精秤した磁性ルツボに試料約１ｇを取り、精秤する。５００℃に設定した電気炉中で２時間強熱する。デシケータ中で１時間放冷後その重量を精秤し次式より算出する。
【０１８１】
強熱減量（％）＝強熱による減量（ｇ）／試料量（ｇ）×１００
疎水化度の測定は、２５０ｍｌのビーカー中に装入した蒸留水５０ｍｌに試験すべき生成物０．２ｇを秤取する。先端に、液体中に浸威しているビュレットからメタノールを無機微粉末の総量がぬれるまで滴下する。その際不断に電磁攪拌機でゆっくりと攪拌する。完全に濡らすために必須なメタノール量ａ（ｍｌ）から次式により疎水化度が算出される。
【０１８２】
疎水化度＝（ａ／（５０＋ａ））×１００（％）
また処理された無機微粉末の水分吸着量が１ｗｔ％以下であることが好ましい。好ましくは０．５ｗｔ％以下、より好ましくは０．１ｗｔ％以下、さらに好ましくは０．０５ｗｔ％以下である。１ｗｔ％より多いと、帯電性の低下、耐久時の感光体へのフィルミングを生じる。水分吸着量の測定は、水吸着装置については、連続蒸気吸着装置（ＢＥＬＳＯＲＰ１８：日本ベル株式会社）にて測定した。
【０１８３】
本形態では、結着樹脂、着色剤及びワックスを含む少なくとも結着樹脂、着色剤及びワックスを含むトナーの体積平均粒径が３．５〜５．５μｍであり、個数分布における５．０４μｍ以下の含有量が６０個数％以上含有し、個数分布における３．１７μｍ以下の含有量が５〜３５個数％含有し、６．３５〜１０．１μｍの粒径を有するトナ−粒子が３５体積％以下で含有する粒度分布とする構成である。
【０１８４】
さらに好適な本形態では、少なくとも結着樹脂、着色剤及びワックスを含むトナーの体積平均粒径が３．５〜５．５μｍであり、個数分布における５．０４μｍ以下の含有量が６０個数％以上含有し、個数分布における３．１７μｍ以下の含有量が５〜３５個数％含有し、６．３５〜１０．１μｍの粒径を有するトナ−粒子が３０体積％以下で含有し、個数分布における８μｍ以上の含有量が１体積％以下で含有する粒度分布とする構成である。この粒度分布を実現する手段は後述する。
【０１８５】
高解像度画質、さらにはタンデム転写における逆転写の防止、中抜けを防止し、オイルレス定着との両立を図ることを可能とできる。
【０１８６】
画質体積平均粒径が５．５μｍより大きいと画質と転写の両立が図れない。体積平均粒径が３．５μｍより小さいと現像でのトナー粒子のハンドリグ性が困難となる。個数分布における５．０４μｍ以下の含有量が６０個数％よりも少なくなると、画質と転写の両立が図れない。個数分布における３．１７μｍ以下の含有量が５個数％よりも少ないと画質と転写の両立が図れない。３５個数％よりも多く含有すると現像でのトナー粒子のハンドリグ性が困難となる。６．３５〜１０．１μｍの粒径を有するトナ−粒子が３５体積％よりも多く含有すると、画質と転写の両立が図れない。
【０１８７】
さらには、６．３５〜１０．１μｍの粒径を有するトナ−粒子が３０体積％よりも多く含有し、個数分布における８μｍ以上の含有量が１体積％よりも多く含有すると、画質と転写の両立が図れない。
【０１８８】
また、体積平均粒子径から換算した真球相当の比表面積値Ｓｔ（Ｓｔ＝６／（真比重＊体積平均粒子径））との比表面積比ＳＳｔ（ＳＳｔ＝（Ｓｔ／粉砕されたトナーの比表面積値）が０．４〜０．９とできる。好ましくは０．５〜０．８５、より好ましくは０．５５〜０．８である。０．９よりも大きいと球形化が進み、帯電性の低下を招き、転写時の飛び散り等の弊害を招く。０．４よりも小さいと形状が不定形になり過ぎるか、または過粉砕された微粉量が多い原因である。
【０１８９】
トナーの体積粒径分布の変動係数が１５〜３２％、個数粒径分布の変動係数が１５〜３５％であることが好ましい。より好ましくは、体積粒径分布の変動係数が１５〜３０％、個数粒径分布の変動係数が１５〜３０％、さらに好ましくは、体積粒径分布の変動係数が１５〜２５％、個数粒径分布の変動係数が１５〜２５％である。
【０１９０】
変動係数とはトナーの粒径における標準偏差を平均粒径で割ったものである。コールターカウンタ（コールター社）を使用して測定した粒子径をもとにしたものである。標準偏差は、ｎ個の粒子系の測定を行なった時の、各測定値の平均値からの差の２乗を（ｎ−１）で割った値の平方根であらわされる。
【０１９１】
つまり変動係数とは粒度分布の広がり具合をあわらしたもので、体積粒径分布の変動係数が１５％未満、又は個数粒径分布の変動係数が１５％未満となると、生産的に困難であり、コストアップの要因となる。体積粒径分布の変動係数が３２％より大、または個数粒径分布の変動係数が３５％より大きくなると、粒度分布がブロードとなるとトナーの凝集性が強くなり、感光体へのフィルミング、転写不良、クリーナレスプロセスでの残留トナーの回収が困難となる。
【０１９２】
トナー中の微粉はトナーの流動性、画質、貯蔵安定性、感光体や現像ローラ、転写体ヘのフィルミング、経時特性、転写性、特にタンデム方式での多層転写性に影響する。さらにはオイルレス定着での非オフセット性、光沢性、透光性に影響する。オイルレス定着実現のためにワックス等の離型剤を配合したトナーにおいて、タンデム転写性との両立において微粉量が影響する。
【０１９３】
微粉量が過大になると、分散しきれないワックスがトナー表面の露出が多くなり、感光体、現像ローラ、転写体へのフィルミングが発生する。さらには、微粉は熱ローラとの付着性も大きいためオフセットしやすい傾向にある。またタンデム方式において、トナーの凝集が強くなりやすく、多層転写時に２色目の転写不良を生じ易くなる。一方、微粉量が少なくなると画質の低下を招く。
【０１９４】
粒度分布測定は、コールターカウンタＴＡ−ＩＩ型（コールターカウンタ社）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）及びパーソナルコンピュータを接続して測定する。電解液は濃度１％となるよう界面活性剤（ラウリル硫酸ナトリウム）を加えたもの５０ｍｌ程度に被測定トナーを２ｍｇ程度加え、試料を懸濁した電解液は超音波分散器で約３分間分散処理を行い、コールターカウンタＴＡ−ＩＩ型にてアパーチャー７０μｍのアパーチャーを用いた。７０μｍのアパーチャー系では、粒度分布測定範囲は１．２６μｍ〜５０．８μｍであるが、２．０μｍ未満の領域は外来ノイズ等の影響で測定精度や測定の再現性が低いため実用的ではない。よって測定領域を２．０μｍ〜５０．８μｍとした。
【０１９５】
また、静嵩密度と動嵩密度から算出されるのが圧縮度で、トナー流動性の指標の一つである。トナーの流動性はトナーの粒度分布、トナー粒子形状、外添剤、ワックスの種類や量に影響される。トナーの粒度分布が狭く微粉が少ない場合、トナーの表面に凹凸が少なく形状が球形に近い場合、外添剤の添加量が多い場合、外添剤の粒径が小さい場合は、圧縮度が小さくなりトナーの流動性は高くなる。圧縮度は５〜４０％が好ましい。より好ましくは、１０〜３０％である。オイルレス定着と、タンデム方式多層転写との両立を図ることが可能となる。５％より小さいと、定着性が低下し、特に透光性が悪化しやすい。現像ロ−ラからトナー飛散が多くなりやすい。４０％よりも大きい転写性が低下し、タンデム方式での中抜け、転写不良を生じる。
【０１９６】
高せん断力による混練により、添加するワックスをより微細分散化できる。そのロールの温度設定及び温度勾配、回転数及び負荷電流の混練条件と結着樹脂の軟化点、ガラス転移点を最適な条件で処理させることにより高分散化処理を可能とできる。高せん断力とは狭い間隙で対向させたロールを高速で回転させることにより結着樹脂等のトナー材料に作用する混練力をいい、狭い間隙に挟まれた時に生じる力と、回転速度差を有する回転ロールから受けるせん断力をいう。従来の二軸押出し機では発揮できない混練力を有する。これにより結着樹脂の高分子量成分を低分子量化することが可能となる。
【０１９７】
具体的は、異方向に回転し、加熱または冷却が可能な対向する２本のロールを有し、一方のロール（ＲＬ１）のロール温度ともう一方のロール（ＲＬ２）のロール温度に温度差を設け、かつ前記ロール（ＲＬ１）と前記ロール（ＲＬ２）とを異なる周速で回転させて２本のロール間で混練処理することにより実現できる。さらには一方のロール（ＲＬ１）が前半部と後半部で温度差を有する構成とすることである。
【０１９８】
２本ロールの回転数比を１．１倍〜２．５倍の範囲内で行うことにより混練時に適切なせん断力が生じ、結着樹脂の分子切断、着色剤等の内部添加剤の分散性が向上し、定着性、現像性が向上する。加熱してトナーを溶融し巻き付ける側のロールの回転比を高くする構成である。１．１倍以下であると適切なせん断力が生じず、分散性が向上せず、透光性が悪化する。逆に２．５倍以上であると、生産性が急激に低下し、また分散性が向上せず、現像性の悪化を招く。
【０１９９】
またこのときの２本のロールにかかる負荷電流値の比を１．２５〜１０の範囲となるような条件で混練することで、適切なせん断力が加わりより内添剤の分散性が向上する。この範囲よりも小さいと分散性が向上せず、透光性が悪化する。また生産性も低下する。逆にこの範囲よりも大きいと、ローラにかかる負荷が大きくなりすぎ、超高分子量成分がより低分子量化しすぎるため、非オフセット性が低下し、オフセットが発生するようになる。
【０２００】
図１にトナー溶融混練処理の概略斜視図を、図２に上から見た平面図、図３に左側から見た側面図、図４に巻き付いた状態での断面図を示す。６０１はトナー原料の定量供給機、６０２はロール（ＲＬ１）、６０３はロール（ＲＬ２）、６０４はロール（ＲＬ１）上に巻き付いたトナーの溶融膜である。図４においてロール６０２は時計回り、６０３は反時計回りに回転する。６０２−１はロール（ＲＬ１）の前半部（原料の搬送方向の上流部）、６０２−２はロール（ＲＬ１）の後半部（原料の搬送方向の下流部）、６０３−１はロール（ＲＬ２）の前半部（原料の搬送方向の上流部）、６０３−２はロール（ＲＬ２）の後半部（原料の搬送方向の下流部）、６０５はロール（ＲＬ１）の前半部６０２−１を加熱するための熱媒体の流入口、６０６はロール（ＲＬ１）の前半部６０２−１を加熱した熱媒体の流出口、６０７はロール（ＲＬ１）の後半部６０２−２を加熱又は冷却するための媒体の流入口、６０８はロール（ＲＬ１）の後半部６０２−２を加熱又は冷却した媒体の流出口、６１８はロール（ＲＬ２）の前半部６０３−１を加熱又は冷却するための熱媒体の流入口、６１９はロール（ＲＬ２）の前半部６０３−１を加熱又は冷却した熱媒体の流出口、６０９はロール（ＲＬ２）の後半部６０３−２を加熱又は冷却するための媒体の流入口、６１０はロール（ＲＬ２）の後半部６０３−２を加熱又は冷却した媒体の流出口、６１１はロール表面のスパイラル状の溝で深さは２〜１０ｍｍ程度、６１２はロール間で形成されるトナー溜りである。６１１の螺旋状の溝はトナーの混練時に材料が原料投入部の右端から排出部の左端にスムーズに搬送されるに好ましいものである。６０３−１は原料をロールに効率よく巻き付かせるために、適当な熱を付加させるためのものである。
【０２０１】
定量供給機から原料供給フィーダ６１３を伝わりながら開口部６１４からトナー原料が矢印６１５のようにロール（ＲＬ１）６０２−１側の端部付近に落下させる。供給フィーダの開口部の長さは６１６で表させる。この長さはロール半径の１／２〜４倍の長さが好ましい。短いと落下させる材料が溶融する前に２本のローラの隙間から下に落下する量が急増する。長すぎると原料フィーダでの搬送途中で原料が分離して均一な分散が得られない。
【０２０２】
また落下位置は図４の矢印にて図示するようにロール（ＲＬ１）６０２の２本のロールが最近接する点から２０°〜８０°の範囲の地点に落下させる。２０°よりも小さい角度であると２本のロールの隙間から落下する量が急増する。８０°以上であると落下させる際、トナー粉末の舞上りが多くなり周辺を汚染する。またカバー６１７は開口部長さ６１６よりも広い領域をカバーできるように設置する。図３ではカバーの図示は省略している。
【０２０３】
定量供給機６０１からトナー原料は供給フィーダ６１３を伝わりながら開口部６１４から落下する。落下したトナー原料はロール（ＲＬ１）６０２−１側の端部付近に投下される。そして６０２−１の熱とロール（ＲＬ２）６０３との圧縮せん断力により樹脂が溶融し、ロール（ＲＬ１）の前半部６０２−１に巻き付くようになる。その状態がロール（ＲＬ１）の後半部６０２−２の端部にまで広がり、ロール（ＲＬ１）の前半部６０２−１よりも低い温度で加熱又は冷却されたロール（ＲＬ２）の後半部６０２−２からトナー魂として剥離される。なお、上記処理の間、ロール６０３は室温以下に冷却されている。ロール（ＲＬ１）６０２とロール（ＲＬ２）６０３のクリアランスは０．１〜０．９ｍｍである。本実施例では原料投入量は１０ｋｇ／ｈ、ロール（ＲＬ１）（ＲＬ２）の直径は１４０ｍｍ、長さは８００ｍｍで行った。
【０２０４】
本形態に係るトナーは、小粒径粉砕を可能し、粗粉側の分布をシャープにするため、トナー組成物を溶融混練した後、表面に凹凸を有し高速に回転する円筒状の回転体と、回転体の外側に０．５ｍｍ〜４０ｍｍの間隙を存して嵌装され、回転体と中心軸を共有する表面に凹凸を有する円筒状の固定体と、被トナー粉砕物を流入させる供給口と、粉砕処理されたトナー粉砕物を排出する排出口とを具備する粉砕機により、所定の粒度分布に粉砕される。このとき、被トナー粉砕物を供給口から流入させる前に、被トナー粉砕物の凝集を緩和する手段を付加させ、前記供給口から流入させて所定の粒度分布へ粉砕させる構成とする。
【０２０５】
被トナー粉砕物の凝集を緩和する手段としては、被トナー粉砕物を供給口から流入させる前に、被トナー粉砕物に蒸発性の媒体、例えば、水蒸気、エタノール、ｉｓｏ−プロピルアルコール、ｎ−ブチルアルコール、ｓｅｃ−ブチルアルコール、ｉｓｏ−ブチルアルコール等で粉体の電荷を除去できることが目的である。被トナー粉砕物に霧状に噴霧供給して混合又は付着させ、粉砕供給口から流入させる方法である。
【０２０６】
また、被トナー粉砕物を供給口から流入させる前に、前記被トナー粉砕物に振動手段を付加させて、供給する方法で、振動手段としては超音波振動、バイブレーション振動等がある。被トナー粉砕物が配管内を通過して粉砕部供給口から流入させる前に配管部に振動装置を具備させ、被トナー粉砕物を分散させながら供給口から流入させる。
【０２０７】
また、被トナー粉砕物を供給口から流入させる前に、前記被トナー粉砕物に無機微粉末を前記被トナー粉砕物に供給して混合させ、前記供給口から流入させて粉砕する方法がある。無機微粉末としては前述した材料が適当である。トナーを粉砕処理する際、被トナー粉砕物を供給口から流入させる前に、被トナー粉砕物に無機微粉末を供給して混合させ、供給口から流入させて所定の粒度分布へ粉砕する構成をとる。これにより被トナー粉砕物が均一に分散した状態で回転体を有する粉砕部に突入し、回転体の生ずる渦流により被トナー粉砕物が均一に粉砕される。これにより、より小粒径化粉砕と、粗粉をシャープにカットされた状態での粉砕が可能となる。
【０２０８】
このとき供給して混合させる無機微粉末が、平均粒径８〜４０ｎｍ、強熱減量が０．５〜２５ｗｔ％であるシリカ又は酸化チタン微粉末が好ましい。さらには脂肪酸エステル、脂肪酸アミド、脂肪酸金属塩のいずれか１種または２種以上を表面処理したシリカ又は酸化チタン微粉末が好ましい。さらには、無機微粉末が、シリコーンオイルを表面処理したシリカ又は酸化チタン微粉末が好ましい材料である。また被トナー粉砕物の電荷を緩和する目的でトナー母体粒子の帯電極性と逆帯電極性を有する無機微粉末も有効な手段である。
【０２０９】
平均粒径が８ｎｍより小さいと、定量切出しが不安定となる。平均粒径が４０ｎｍより大きいと均一粉砕性が良くならない。強熱減量が０．５ｗｔ％より小さいと、微粉末が飛散してしまう。強熱減量が２５ｗｔ％より大きいと微粉末の凝集が強くなり、被トナー粉砕物の均一供給性が悪くなる。
【０２１０】
この無機微粉末はトナー母体に固着されることなく静電気的な付着状態でトナー表面に付着する。投入量の約半分量程度以下がバグフィルターにもっていかれている。無機微粉末の供給量としては被トナー粉砕物の供給量の０．１〜５ｗｔ％程度が好ましい。
【０２１１】
回転体の凸部と、固定体の凸部との間隙を０．５〜４０ｍｍ、好ましくは０．５〜１０ｍｍ、より好ましくは０．５〜６ｍｍにすることにより粉砕効率と球形化作用をより高めることができる。０．５ｍｍより小さいと粒子と回転体、固定体との接触が著しく増大するので、摩擦熱の発生が著しくなり、上記の先端部でトナーの融着が生じる。４０ｍｍより大きいと高速気流の激しい流動を発生させることができず、充分な粉砕性が得られない。
【０２１２】
この方式で行うと粉砕と同時に球形化処理を施すことが可能であるため、製造工程が短縮できるメリットが大きい。この方式により、トナーは粒子の角がきれいに取られ球形化されるため、流動性は飛躍的に向上する。
【０２１３】
トナーの流動性が低いとベタ画像部にムラが発生したり、摩擦帯電性が低下し、逆極性トナーが増加し、感光体の非画像部にトナーが強く付着し除去できず、地カブリとなって画像を劣化させるし、また転写効率が低下する。外添剤シリカを増量してトナーの流動性を上げると、摩擦帯電が均一化し、地カブリの減少と、画像濃度の増加、ベタ黒画像部のムラが解消される傾向にある。しかし感光体へのシリカやトナーのフィルミングや、シリカ凝集物のベタ黒画像部への白点付着等の課題が発生する。
【０２１４】
そのため、少量のシリカの添加量で高流動性が得られ、浮遊シリカの発生が抑えられ、ベタ黒画像部へのシリカの白点や、中間転写体や感光体へのシリカ、トナーフィルミングの発生が抑えられる。また低流動性のトナーで見られるベタ黒画像部のムラの発生が抑えられ、均一な転写性が得られ、さらに逆極性トナーの発生を低く抑えられるため、転写効率が向上する要因となる。
【０２１５】
さらに転写時において、特に高温高湿時、文字やライン等のトナーが集中しているところで、所定の押圧力で転写しても、トナーの高流動性のため、トナー同士の凝集が起きにくく、中抜けのない鮮明な画像が得られる。
【０２１６】
図５に示した本形態のトナーの粉砕装置の１実施例について説明する。
【０２１７】
混練物を粗粉砕によりメッシュ径約１〜５ｍｍパスした被トナー粉砕物５０３は定量供給機５０８から投入され、冷却器５０９によって供給される冷却エアー５１１により、粉砕供給部に送られ、粉砕処理部５００で粉砕される。原料５０３は入口５０４から投入され、高速に回転し表面に凹凸部５０６を有する回転体５０１と、この回転体５０１と狭ギャップの間隙で位置している表面に凹凸部５０７を有する固定体５０２との空間に運ばれ、高速に回転する回転体と固定体の間に発生する高速気流の流動に伴って、原料粒子相互が強力な衝突により粉砕されながら球形化される。球形化された粒子５１０は排出口５０５から出て、粗粉分級機５１３に送られ、粗い粒子は再度エアー５１１により、入口５０４に送られる。製品はサイクロン５１５に送られ、補集容器５２０に回収される。５１２は温度計、５１４はバグフィルター、５１６は風量計、５１７はブロアである。
【０２１８】
５１９はバイブレータ振動装置、５１８は無機微粉末供給装置である。粗粉分級により分離され再度粉砕部に供給されるとき、無機微粉末供給をその後ろから供給することが好ましい。これにより無機微粉末が粉砕物への衝突の際に均一に混合される。無機微粉末の代わりに蒸発性の溶剤を媒体を供給できる。本実施例では、粉砕条件▲１▼回転体の周速：１３０ｍ／ｓ、回転体と固定体の間隙：１．５ｍｍ、被トナー粉砕物の供給量：５ｋｇ／ｈ、無機微粉末の供給量：０．０３ｋｇ／ｈ、冷却空気温度：０℃、排出部温度：４５℃、粉砕条件▲２▼回転体の周速：１２０ｍ／ｓ、回転体と固定体の間隙：１ｍｍ、被トナー粉砕物供給量：５ｋｇ／ｈ、無機微粉末の供給量：０．０２ｋｇ／ｈ、冷却空気温度：０℃、排出部温度：４０℃で行った。
【０２１９】
小粒径トナーの作成方法としては、一般に乳化重合法、懸濁重合方法なども好適に使用できる。
【０２２０】
一般的な乳化重合法では、イオン性界面活性剤を含有する樹脂微粒子分散液を調製し、着色剤粒子分散液及び離型剤粒子分散液と混合し、前記イオン性界面活性剤とは反対の極性を有するイオン性界面活性剤により凝集を生じさせることによりトナー径の凝集粒子を形成し、その後、樹脂微粒子のガラス転移点以上の温度に加熱して前記凝集粒子を融合して、洗浄、乾燥する手段により作成されるトナーにも適用可能である。
【０２２１】
この時使用する界面活性剤を例示すると、硫酸エステル塩系、スルホン酸塩系、リン酸エステル系、せっけん系等のアニオン性界面活性剤、及びアミン塩型、４級アンモニウム塩型等のカチオン性界面活性剤を使用することができる。また、ポリエチレングリコール系、アルキルフェノールエチレンオキサイド付加物系、多価アルコール系等の非イオン性界面活性剤を併用することも効果的である。これらの分散手段としては、回転剪断型ホモジナイザーやメディアを有するボールミル、サンドミル、ダイノミルなどの一般的なものを使用できる。
【０２２２】
粒子生成後は、任意の洗浄工程、固液分離工程、乾燥工程を経て所望のトナーを得ることができるが、洗浄工程は、帯電性を発現・維持するため、十分にイオン交換水による置換洗浄を施すことが好ましい。また、固液分離工程は、特に制限はないが、生産性の点から吸引濾過、加圧ろ過等が好ましく用いられる。さらに乾燥工程も特に制限はないが、生産性の点から凍結乾燥、フラッシュジェット乾燥、流動乾燥、振動型流動乾燥等が好ましく用いられる。
【０２２３】
また懸濁重合法では、一般に重合性単量体、ワックス、着色剤等の各種添加剤を均一に溶解または分散させて加熱しホモジナイザー、超音波分散機等によって均一に溶解又は分散せしめ単量体組成物としたのち、単量体系を、分散安定剤を含有する単量体系と同温の水相中に通常の攪拌機又はホモミキサー・ホモジナイザー等により分散せしめる。
【０２２４】
好ましくは、単量体液滴が所定のトナー粒子のサイズ、一般に２０μｍ以下の粒径を有するように攪拌速度・時間を調整し、その後は分散安定剤の作用により、粒子状態が維持され、かつ粒子の沈降が防止される程度の攪拌を行えば良い。重合温度は４０℃以上、一般には５０〜８０℃の温度に設定させる。
【０２２５】
このとき定着助剤の高分散化と、定着助剤を包含したトナー粒子を小さく均一な粒度分布とするためにも、攪拌速度は３０ｍ／ｓｅｃ以上が好ましい。
【０２２６】
反応終了後、生成したトナー粒子を洗浄、ろ過により回収し、乾燥する。懸濁重合においては通常単量体系１００重量部に対して水３００〜３０００重量部を分散媒として使用するのが好ましい。
【０２２７】
用いられる分散媒は、いずれも適当な安定化剤、有機化合物として、ポリビニルアルコール、ゼラチン、メチルセルコロース、メチルヒドロキシプロピルセルロース、エチルセルロース、カルボキシメチルセルロースのナトリウム塩、ポリアクリル酸及びその塩、デンプン、無機化合物としては、りん酸三カルシウム、リン酸マグネシウム、リン酸アルミニウム、リン酸亜鉛、炭酸カルシウム、炭酸マグネシウム、硫酸バリウム、硫酸カルシウム、水酸化アルミニウム、水酸化マグネシウム、メタケイ酸カルシウム、ベントナイト、シリカ、アルミナ等を水相に分散させて使用できる。
【０２２８】
分散安定剤の中で、無機化合物を用いる場合、より細かい粒子を得るため、水系媒体中で該無機化合物を生成させても良い。例えば、りん酸カルシウムの場合高速攪拌下において、リン酸ナトリウム水溶液と塩化カルシウム水溶液を混合すると良い。
【０２２９】
またこれらの安定化剤の微細な分散のために、０．００１〜０．１重量部の界面活性剤を使用しても良い。これは上記分散安定剤の所期の作用を促進するためのものであり、その具体例として、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、ペンタデジル硫酸ナトリウム、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、ステアリン酸カリウム、オレイン酸カルシウム等が挙げられる。
【０２３０】
２，２’−アゾビスー（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（シクロヘキサンー１−カルボニトリル）、２，２’−アゾビスー４−メトキシー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又はジアゾ系重合開始剤が使用できる。
【０２３１】
本形態の現像プロセスにおいては、マグネタイト、フェライト粒子に樹脂コートした抵抗が１×１０^９〜１×１０^１４、粒径３０〜８０μｍのキャリアと混合して二成分現像として好適に使用される。
【０２３２】
感光体と現像ローラ間には直流バイアスと共に交流バイアスを印加する。
【０２３３】
そのときの周波数が１〜１０ｋＨｚ、交流バイアスが１．０〜２．５ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．２〜１：２であることが好ましい。
【０２３４】
より好ましくは周波数が３．５〜８ｋＨｚ、交流バイアスが１．２〜２．０ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．５〜１：１．８である。
【０２３５】
更に好ましくは周波数が５．５〜７ｋＨｚ、交流バイアスが１．５〜２．０ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．６〜１：１．８である。
【０２３６】
この現像プロセス構成と本形態のトナーの使用により、ドットを忠実に再現でき、現像γ特性をねかせる特性とできる。高画質画像とオイルレス定着性を両立できる。また高抵抗キャリアでも低湿下でのチャージアップを防止でき、連続使用においても高画像濃度を得ることができる。これは高帯電性を発現できるトナー、キャリア構成と交流バイアスとの併用により、キャリアとの付着力を低減でき画像濃度を維持できると共にカブリを低減でき、ドットをも忠実に再現できるものと思われる。
【０２３７】
周波数が１ｋＨｚより小さいと、ドット再現性が悪化し、中間調再現性が悪化する。周波数が１０ｋＨｚより大きくなると、現像領域での追随ができず、効果が現れない。この周波数の領域では高抵抗キャリアを使用した二成分現像において、現像ローラと感光体間よりもキャリアとトナー間での往復作用に働き、トナーをキャリアから微少に遊離させる効果があり、これによりドット再現性、中間調再現性が良好に行われ、かつ高画像濃度を出すことが可能になる。
【０２３８】
交流バイアスが１．０ｋＶ（ｐ−ｐ）より小さくなると、チャージアップの抑制の効果が得られず、交流バイアスが２．５ｋＶ（ｐ−ｐ）より大きくなるとカブリが増大する。感光体と現像ローラ間の周速度比が１：１．２より小さいと（現像ローラが遅くなる）画像濃度が得にくい。感光体と現像ローラ間の周速度比が１：２より大きくなると（現像ローラ速度が上がる）とトナー飛散が多くなる。
【０２３９】
二成分現像として使用使用する時のキャリアとしては、フェライト粒子表面に樹脂被覆層を設けることにより作成される。フェライトはＦｅ_２Ｏ_３を主原料に、ＮｉＯ、ＣｕＯ、ＣｏＯ，ＭｇＯ、ＺｎＯ，ＭｎＣＯ_３、ＢａＣＯ_３、ＳｒＣＯ_３を混合して原料に用いる。フェライト粒子は、湿式法、乾式法で作成されるが、乾式法が好ましい。乾式法では、原料を混合後仮焼成し、水中にてボールミル等で微粉砕化し、さらに結着剤としてポリビニルアルコール、消泡剤、分散剤を加え造粒用スリラーとする。このスリラーを噴霧乾燥機で加熱乾燥しながら造粒し顆粒とし、本焼成する。本焼成は９００〜１４００℃で３〜３０時間行い、その後解砕、分級してフェライト粒子を得る。
【０２４０】
被覆層は、スプレー法、ディッピング法等公知の方法が用いられる。被覆量はキャリア粒子重量の０．１〜２ｗｔ％である。樹脂被覆層に用いる樹脂は、フッ素系樹脂またはシリコーン系樹脂が用いられる。樹脂被覆層に含有させるカーボンブラックは、種々の製法のカーボンブラックが用いられるが、オイルファーネスカーボンヤアセチレンブラックが好ましい。
【０２４１】
例えば、ＭｎＯを３５ｍｏｌ％、ＭｇＯを１５ｍｏｌ％、Ｆｅ_２Ｏ_３を４４．５ｍｏｌ％及びＳｒＣＯ３を０．５ｍｏｌ％湿式ボールミルで、５時間粉砕し、混合し、乾燥させた後、８５０℃で１時間保持し、仮焼成を行った。これを湿式ボールミルで７時間粉砕し、３μｍ以下とした。このスリラーに分散剤、及びバインダを適量添加し、次いでスプレードライヤにより造粒し、乾燥し、電気炉にて、１２００℃で４時間保持し、本焼成を行った。その後、解砕し、さらに分級して平均粒径５０μｍ、３０−７０μｍの粒度分布をもつフェライト粒子の芯材を得た。その造粒フェライト粒子の成分分析を行ったところ、ＭｎＯが３５ｍｏｌ％、ＭｇＯが１４．５ｍｏｌ％、ＳｒＯが０．５ｍｏｌ％、Ｆｅ_２Ｏ_３が５０ｍｏｌ％であった。
【０２４２】
これらのフェライト粒子を芯材として、シリコーン系樹脂（商品名：ＳＲ−２４１１、固形分２０ｗｔ％、東レダウコーニングシリコーン社製）をトルエン溶剤に溶解させ、流動床を用いてキャリア芯材に対し、０．６ｗｔ％コーティングし、さらに２５０℃で３時間焼き付けを行い、樹脂被覆されたキャリアを得た。
【０２４３】
キャリアの平均粒径は３０〜７０μｍが好ましい。キャリアの平均粒径が３０μｍ未満では、キャリアが感光体に現像されやすくなり、キャリアの平均粒径が７０μｍより大きくなるとキャリアのトナー保持力が弱くなるため、トナー飛散が発生する。
【０２４４】
本形態の現像プロセスにおいては、弾性又は剛性の現像ローラ上にゴムやメタル等の弾性ブレード等を一定の圧力により接触させ、トナーの薄層を形成して感光体と接触又は非接触により現像する一成分現像法として好適に使用できる。一成分現像法としては、ウレタン樹脂からなるスポンジ系の供給ローラとシリコーン樹脂又はウレタン樹脂からなる現像ローラを一定の食い込み量により接触させ、供給ローラから現像ローラにトナーを供給し、現像ローラ上に弾性体のゴムや金属ステンレスのドクターブレードを接触して、または金属性のローラを現像ローラとアゲインスト（同方向）に回転接触して、トナーの薄層を形成し、それを感光体と接触または非接触にて直流または交流印可してトナー像を形成する現像法が好適に使用される。
【０２４５】
このとき、交流バイアスの周波数が０．５〜１０ｋＨｚ、交流バイアスが０．３〜１．２ｋＶ（ｐ−ｐ）であり、感光体と現像ローラ間の周速度比が１：１．２〜１：１．８とすることにより、ドットを忠実に再現でき、良好な現像γ特性とでき、高画質画像を実現できる。そして低地カブリ、高画像濃度が得られる。周波数が０．５〜５ｋＨｚ、交流バイアスが０．３〜１．０ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．２〜１：１．５がより好ましく、更に好ましくは周波数が０．５〜２ｋＨｚ、交流バイアスが０．５〜０．９ｋＶ（ｐ−ｐ）であり、かつ感光体と現像ローラ間の周速度比が１：１．２〜１：１．４である。
【０２４６】
このとき、周波数が０．５ｋＨｚより小さいと、ドット再現性が悪化し、中間調再現性が悪化する。周波数が１０ｋＨｚより大きくなると、現像領域での追随ができず、効果が現れない。交流バイアスが０．３ｋＶ（ｐ−ｐ）より小さくなると、ベタ追随性維持効果が得られず、交流バイアスが１．２ｋＶ（ｐ−ｐ）より大きくなるとカブリが増大する。感光体と現像ローラ間の周速度比が１：１．２より小さいと（現像ローラが遅くなる）画像濃度が得にくい。感光体と現像ローラ間の周速度比が１：１．８より大きくなると（現像ローラ速度が上がる）とトナー飛散が多くなる。
【０２４７】
供給ローラと現像ローラは同方向に回転させ、現像ローラと供給ローラの周速を１：１〜０．８：０．２の割合で現像ローラを早くする構成とする。また現像ローラは感光体表面に９．８〜９．８×１０^２（Ｎ）の圧力で圧接して感光体上の静電潜像が現像される。また弾性ブレードは５〜５×１０^２（Ｎ）の圧力で現像ローラ上に圧接してトナー層が形成される。
【０２４８】
さらに、トナー溜めから供給されるトナーの供給量を現像ローラ上へ搬送する際の現像ローラ上のトナー搬送量を一定量に制御するため、ウレタン樹脂等からなるスポンジ状の供給ローラを、現像ローラに対し一定の食い込み量０．１〜１ｍｍで、現像ローラと接触させる構成が取られる。
【０２４９】
トナー溜めから供給されるトナーの供給量を現像ローラ上へ搬送する際の現像ローラ上のトナー搬送量を一定量に制御するため、ウレタン樹脂等からなるスポンジ状の供給ローラを現像ローラと接触させて具備する構成が取られる。これはトナーの搬送量を一定量に規制するために有効な手段である。
【０２５０】
ただ従来のトナーでは、この現像構成においては、長期使用していると現像ローラ上での傷や、ブレードに異物の付着により画像上に縦筋が生じる画像不良が発生しやすい。特にカラー定着性を向上させるために、低軟化性の結着樹脂の使用や、低融点離型剤を添加したトナーではより顕著に発生する。
【０２５１】
また、長期連続使用中に現像ローラ上のトナーの搬送量が低下したり、べた黒画像を取った場合に画像後半部の濃度が部分的に低下するベタ追随性不良が発生しやすい。現像ローラ上のトナーの帯電量を吸引式により測定すると帯電量が大きく低下していることが分かった。さらに追求すると供給ローラ部のトナーの帯電量が大きく増加しており、つまり画像濃度の低下はトナーの帯電量が低下しているのではなくて、現像ローラに供給される前の供給ローラ部においてチャージアップしており供給ローラから現像ローラへの供給能力が低下したためである。よってトナーの飛散を防ぎながら画像濃度を確保できる構成が必要になる。ドクターブレードの圧接力を高めてトナーの帯電能力を上げる構成も有効であるが、トナーの融着を招きやすく現像ローラに傷を生じさせる。
【０２５２】
そこで、本形態のトナー構成とすることにより、定着特性を犠牲にすることなく、現像ローラ上の縦筋の発生、ベタ追随性不良、トナーの融着を防止することができることを見い出した。
【０２５３】
これは樹脂中での均一分散が可能となり、帯電分布が安定化し供給ローラでのトナーの過帯電を抑えると共に、流動性が安定化でき、ベタ画像の追随性も良好なものとなる。均一分散によりトナーの流動性が維持でき現像ローラ上でのトナーの搬送状態をスムーズなものとし、搬送状態を常に安定化できる効果がある。特に高湿下での搬送状態の安定化に効果が大きい。このとき現像ローラ上のトナーの吸引式ファラデーケージ法によるトナーの帯電量が｜５｜〜｜４５｜μＣ／ｇであることが好ましい。｜５｜μＣ／ｇ以下であるとトナー飛散が増大する。｜４５｜μＣ／ｇ以上となると画像濃度が出にくい。
【０２５４】
吸引式ファラデーケージ法によるトナーの帯電量測定は、現像ローラ上のトナーを回転させながら、吸引し、吸引されたトナーはフィルターに捕集し、その重量Ｗ（ｇ）を得る。また吸引時に帯電されたトナーが移動する際の電荷量をコンデンサに誘起される電圧Ｖ（Ｖ）を測定し、Ｑ（μＣ／ｇ）＝Ｃ（Ｆ）×Ｖ（Ｖ）／Ｗ（ｇ）から帯電量を算出する。
【０２５５】
また、高速にカラー画像を形成するために、本形態では、感光体と帯電手段とトナー担持体を含むトナー像形成ステーションを複数個有し、像担持体上に形成した静電潜像を顕像化したトナー像を、前記像担持体に無端状の転写体を当接させて前記転写体に転写させる一次転写プロセスが順次連続して実行して、前記転写体に多層の転写トナー画像を形成し、その後前記転写体に形成した多層のトナー像を、一括して紙やＯＨＰ等の転写媒体に一括転写させる二次転写プロセスが実行されるよう構成された転写プロセスにおいて、第１の一次転写位置から第２の一次転写位置までの距離をｄ１（ｍｍ）、感光体の周速度をｖ（ｍｍ／ｓ）とした場合、ｄ１／ｖ≦０．６５となる転写位置構成を取る構成であるが、例えば１色目のイエロートナーが一次転写された後、次の２色目のマゼンタトナーが一次転写されるまでの時間が極めて短く、転写体の帯電緩和又は転写されたトナーの電荷緩和が殆ど生じず、イエロートナーの上にマゼンタトナーを転写する際に、マゼンタトナーがイエロートナーの電荷作用により反発され、転写効率の低下、転写時の文字の中抜けという問題が生じる。さらに第３色目のシアントナーの一次転写の時、前のイエロー、マゼンタトナーの上に転写される際にシアントナーの飛び散り、転写不良、転写中抜けが顕著に発生する。さらに繰り返し使用しているうちに特定粒径のトナーが選択的に現像され、トナー粒子個々の流動性が大きく異なると摩擦帯電する機会が異なるため、帯電量のバラツキが生じ、より転写性の劣化を招いてしまう。
【０２５６】
そこで、本形態のトナー構成とすることにより、樹脂中でのワックス等の内添剤が均一分散化し、帯電分布が安定化し供給ローラでのトナーの過帯電を抑えると共に、流動性変動を抑えることができるため、定着特性を犠牲にすることなく、転写効率の低下、転写時の文字の中抜けを防止することができる。
【０２５７】
実施の形態１１；クリーナレスプロセス
また、本形態では、転写プロセス後に感光体上に残留したトナーをクリーニングにより回収するクリーニングプロセス工程を有さずに、次の帯電、露光、現像プロセスを行うクリーナレスプロセスを基本構成とする電子写真装置に好適に使用される。
【０２５８】
本形態のトナーの使用により、トナーの凝集を抑え、過帯電を防止し、帯電性の安定化が得られ、高転写効率を得ることが可能となる。また樹脂中での均一分散性の向上、良好な帯電性、材料の有する離型性により、非画像部に残留したトナーの現像での回収が良好に行える。そのため、非画像部の前の画像パターンが残る現像メモリーも発生もない。
【０２５９】
本形態では、トナーを定着する手段にベルト式の定着媒体を使用する構成の定着プロセスを具備する電子写真装置に好適に使用される。そのベルトとしては耐熱性と変形自在性とを有するニッケル電鋳ベルトやポリイミドベルトの耐熱ベルトが用いられる。離形性を向上するために表面層としてシリコーンゴム、フッ素ゴム、フッ素樹脂を用いる構成である。これらの定着ベルトにおいてはこれまでは離型オイルを塗布してオフセットを防止してきた。オイルを使用せずに離型性を有するトナーにより、離型オイルを塗布する必要はなくなった。しかし離型オイルを塗布しないと帯電しやすく、未定着のトナー像がベルトと近接すると帯電の影響により、トナー飛びが生じる場合がある。特に低温低湿下において発生しやすい。またトナーが高温オフセット防止のため一定以上の高分子量成分を付加し、ある程度の弾性要素を持たせたとき、トナーの細い縦線のパターンを描いた紙が曲率の大きいベルトからの隔離時に先端部がベルトに持っていかれる先端オフセットが生じる場合がある。また従来の剛性の定着ローラと比べて弾性体のベルト式では、オイルレスにより傷による寿命低下が問題となる。
【０２６０】
そこで、本形態のトナーの使用により、オイルを使用せずともオフセットの発生を防止でき、カラー高透光性を得ることができる。またトナーの過帯電性を抑制できベルトとの帯電作用によるトナーの飛びを抑えられる。またベルトからの隔離時に先端部がベルトに持っていかれるオフセットトナーの分子量分布と滑性の効果により防止することが可能となる。
【０２６１】
次に、実施例により本発明を更に詳細に説明する。ただし本発明はこれに限定されるものではない。
【０２６２】
（表１）に実施例で使用する結着樹脂の特性を示す。樹脂はビスフェノールＡプロピルオキシド付加物、テレフタル酸、トリメリット酸、コハク酸、フマル酸を主成分としたポリエステル樹脂を使用し、配合比、重合条件により熱特性を変えた樹脂を使用した。
【０２６３】
【表１】

【０２６４】
Ｍｎｆは結着樹脂の数平均分子量、Ｍｗｆは結着樹脂の重量平均分子量、Ｍｚｆは結着樹脂のＺ平均分子量、Ｗｍｆは重量平均分子量Ｍｗｆと数平均分子量Ｍｎｆとの比Ｍｗｆ／Ｍｎｆ、Ｗｚｆは結着樹脂のＺ平均分子量Ｍｚｆと数平均分子量Ｍｎｆの比Ｍｚｆ／Ｍｎｆ、ＡＶは樹脂酸価を示す。
【０２６５】
（表２）（表３）（表４）に本実施例で使用するワックス及びその物性値を示す。Ｍｎｒはワックスの数平均分子量、Ｍｗｒはワックスの重量平均分子量、ＭｚｒはワックスのＺ平均分子量を示す。Ｔｗ（℃）はＤＳＣ法による融点、Ｃｔ（％）は融点＋１０℃での容積増加率（％）、Ｃｋ（ｗｔ％）は２２０℃の加熱減量を示す。
【０２６６】
【表２】

【０２６７】
【表３】

【０２６８】
【表４】

【０２６９】
（表５）に本実施例で使用する顔料を示す。
【０２７０】
【表５】

【０２７１】
（表６）に本実施例で使用する電荷制御剤及びその物性値を示す。
【０２７２】
サリチル酸誘導体の金属塩として、炭素数１〜１０のアルキル基としては例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基、ｓｅｃ−ブチル基、ｔｅｒｔ−ブチル基等が挙げられる。金属Ｙとしては亜鉛、ニッケル、コバルト、銅、クロムが挙げられ、亜鉛、クロムが好ましい。ベンジル酸誘導体の金属塩としては、Ｒ^１〜Ｒ^４がベンゼン環、アルカリ金属Ｘとしてはリチウム、ナトリウム、カリウム等が挙げられ、カリウムが好ましい。
【０２７３】
【表６】

【０２７４】
（表７）に本実施例で使用する外添剤を示す。その帯電量はノンコートのフェライトキャリアとの摩擦帯電のブローオフ法により測定したものである。２５℃４５％ＲＨの環境下で、１００ｍｌのポリエチレン容器にキャリア５０ｇとシリカ等０．１ｇを混合し、縦回転にて１００ｍｉｎ^−１の速度で５分、３０分間攪拌した後、０．３ｇ採取し、窒素ガス１．９６×１０^４（Ｐａ）で１分間ブローした。
【０２７５】
正帯電性では５分間攪拌後の５分値が＋１００〜＋８００μＣ／ｇで、３０分間攪拌後の３０分の値が＋５０〜＋４００μＣ／ｇであることが好ましい。３０分値での帯電量が５分値での帯電量の４０％以上を維持しているシリカが好ましい。低下率が大きいと長期連続使用中での帯電量の変化が大きく、一定の画像を維持できなくなる。
【０２７６】
負帯電性では５分値が−１００〜−８００μＣ／ｇで、３０分の値が−５０〜−６００μＣ／ｇであることが好ましい。高い帯電量のシリカでは少量の添加量で機能を発揮できる。
【０２７７】
【表７】

【０２７８】
本実施例での混練条件を（表８）に示す。Ｔｒｊ１（℃）はロール（ＲＬ１）の前半部の加熱温度、Ｔｒｋ１（℃）はロール（ＲＬ１）の後半部の加熱温度、Ｔｒ２（℃）ロール（ＲＬ２）の加熱温度、Ｒｗ１はロール（ＲＬ１）の回転数、Ｒｗ２はロール（ＲＬ２）の回転数、ロール（ＲＬ１）の回転時の負荷電流値をＤｒ１、ロール（ＲＬ２）の負荷電流値をＤｒ２と示している。原料投入量は１５ｋｇ／ｈ、ロール（ＲＬ１）（ＲＬ２）の直径は１４０ｍｍ、長さは８００ｍｍで行った。
【０２７９】
【表８】

【０２８０】
（表９）（表１０）に本実施例での粉砕条件を示す。
【０２８１】
粉砕前に供給される無機微粉末とその供給量、バイブレータ振動付与、溶剤噴霧処理を施している。
【０２８２】
【表９】

【０２８３】
【表１０】

【０２８４】
（表１１）（表１２）に本実施例に本実施例で使用したトナー材料組成、物性値を示す。
【０２８５】
【表１１】

【０２８６】
【表１２】

【０２８７】
図中、Ｓｓは粉砕されたトナーの比表面積値、Ｓｔは、Ｓｔ＝６／（トナーの真比重×体積平均粒子径）、で表される値、ＳＳｔは、ＳｔをＳｓ（粉砕されたトナーの比表面積値）で割った値である。
【０２８８】
混練のＰＣＭ３０は従来の二軸押出機で、混練温度１１０℃回転数２００ｍｉｎ^−１、供給量５ｋｇ／ｈで処理した。
【０２８９】
顔料、電荷制御剤、ワックスの配合量比は結着樹脂１００重量部に対する配合量（重量部）比を括弧内に示す。外添剤はトナー母体１００重量部に対する配合量（重量部）を示している。外添処理はＦＭ２０Ｂにおいて、攪拌羽根Ｚ０Ｓ０型、回転数２０００ｍｉｎ^−１、処理時間５ｍｉｎ、投入量１ｋｇで行った。
【０２９０】
（表１３）（表１４）に本実施例で混練処理を施した後のトナーの分子量特性を示す。トナーはマゼンタトナーのＴＭ１からＴＭ７トナーで比較評価した。イエロー、シアン、ブラックトナーでも同様な結果になる。Ｍｎｖはトナーの数平均分子量、Ｍｗｖはトナーの重量平均分子量、Ｗｍｖはトナーの重量平均分子量Ｍｗｖと数平均分子量Ｍｎｖの比Ｍｗｖ／Ｍｎｖ、ＷｚｖはトナーのＺ平均分子量Ｍｚｖと数平均分子量Ｍｎｖの比Ｍｚｖ／Ｍｎｖを示す。
【０２９１】
ＭＬは分子量分布において低分子量側の分子量極大ピークを示す分子量値、ＭＨは高分子量側の分子量極大ピークを示す分子量値、ＳｍはＨｂ／Ｈａ、ＳＫ１はＭ１０／Ｍ９０、ＳＫ２は（Ｍ１０−Ｍ９０）／Ｍ９０を示す。
【０２９２】
【表１３】

【０２９３】
【表１４】

【０２９４】
（実施例１）
図６は本実施例で使用したフルカラー画像形成用の画像形成装置の構成を示す断面図である。図６において、カラー電子写真プリンタの外装筐は省略している。プリンタ内の転写ベルトユニット２の着脱操作や紙詰まり時などのプリンタ内部点検保守等は前面板を倒し開いてプリンタ内部を大きく解放することにより行われる。この転写ベルトユニット１７の着脱動作は、感光体の回転軸母線方向に対し平行方向になるように設計されている。
【０２９５】
転写ベルトユニット１７は、転写ベルト１２、弾性体よりなる第１色（イエロー）転写ローラ１０Ｙ、第２色（マゼンタ）転写ローラ１０Ｍ、第３色（シアン）転写ローラ１０Ｃ、第４色（ブラック）転写ローラ１０Ｋ、アルミローラよりなる駆動ローラ１１、弾性体よりなる第２転写ローラ１４、第２転写従動ローラ１３、転写ベルト１２上に残ったトナー像をクリーニングするベルトクリーナブレード１６、クリーナブレードに対向する位置にローラ１５を設けている。
【０２９６】
このとき、第１色（Ｙ）転写位置から第２色（Ｍ）転写位置までの距離は３５ｍｍ（第２色（Ｍ）転写位置から第３色（Ｃ）転写位置、第３色（Ｃ）転写位置から第４色（Ｋ）転写位置も同様距離）、感光体の周速度は１００ｍｍ／ｓである。
【０２９７】
転写ベルト１２は、絶縁性ポリカーボネート樹脂中に導電性のフィラーを混練して押出機にてフィルム化して用いる。本実施例では、絶縁性樹脂としてポリカーボネート樹脂（たとえば三菱ガス化学製，ユーピロンＺ３００）９５重量部に、導電性カーボン（たとえばケッチェンブラック）５重量部を加えてフィルム化したものを用いた。また、表面にフッ素樹脂をコートし、厚みは約１００μｍ、体積抵抗は１０^７〜１０^１２Ω・ｃｍ、表面抵抗は１０^７〜１０^１２Ω／□である。ドット再現性を向上させためもある。転写ベルト１２の長期使用による弛みや，電荷の蓄積を有効に防止できるようにするためであり、また、表面をフッ素樹脂でコートしているのは、長期使用による転写ベルト表面へのトナーフィルミングを有効に防止できるようにするためである。体積抵抗が１０^７Ω・ｃｍよりも小さいと、再転写が生じ易く、１０^１２Ω・ｃｍよりも大きいと転写効率が悪化する。
【０２９８】
第１転写ローラは外径１０ｍｍのカーボン導電性の発泡ウレタンローラで、抵抗値は１０^２〜１０^６Ωである。第１転写動作時には、第１転写ローラ１０は、転写ベルト１２を介して感光体１に１．０〜９．８（Ｎ）の押圧力で圧接され、感光体上のトナーがベルト上に転写される。抵抗値が１０^２Ωよりも小さいと、再転写が生じ易い。１０^６Ωよりも大きいと転写不良が生じ易くなる。１．０（Ｎ）よりも小さいと転写不良を生じ、９．８（Ｎ）よりも大きいと転写文字抜けが生じる。
【０２９９】
第２転写ローラ１４は外径１５ｍｍのカーボン導電性の発泡ウレタンローラで、抵抗値は１０^２〜１０^６Ωである。第２転写ローラ１４は、転写ベルト１２及び紙、ＯＨＰ等の転写媒体１９とを介して転写ローラ１３に圧接される。この転写ローラ１３は転写ベルト１２に従動回転可能に構成している。第２次転写での第２転写ローラ１４と対向転写ローラ１３とは５．０〜２１．８（Ｎ）の押圧力で圧接され、紙等の記録材上１９に転写ベルトからトナーが転写される。抵抗値が１０^２Ωよりも小さいと、再転写が生じ易い。１０^６Ωよりも大きいと転写不良が生じ易くなる。５．０（Ｎ）よりも小さいと転写不良となり、２１．８（Ｎ）よりも大きいと負荷が大きくなり、ジッタが出やすくなる。
【０３００】
図６において、イエロー（Ｙ）、マゼンタ（Ｍ）、シアン（Ｃ）、黒（Ｂ）の各色用の４組の像形成ユニット１８Ｙ、１８Ｍ、１８Ｃ、１８Ｋが、図のように直列状に配置されている。
【０３０１】
各像形成ユニット１８Ｙ、１８Ｍ、１８Ｃ、１８Ｋ、中に入れた現像剤を除きそれぞれ同じ構成部材よりなるので、説明を簡略化するためＹ用の像形成ユニット１８Ｙについて説明し、他色用のユニットの説明については省略する。
【０３０２】
像形成ユニットは以下のように構成されている。１は感光体、３は画素レーザ信号光、４はＪＩＳ−Ａ硬度６０°のシリコーンゴムよりなる外径１２ｍｍの現像ロ−ラで、感光体に２１Ｎの力で圧接され、矢印の方向に回転する。６は外径１０ｍｍの導電性ウレタンスポンジよりなる供給ローラで、トナーホッパ内のトナーを現像ローラに供給する。５は金属製のブレードで現像ローラ上にトナーの層を形成する。電源は、省略しているが、現像ローラ４には−２３０Ｖの直流と、５００Ｖ（ｐ−ｐ）、周波数１ｋＨｚの交流電圧が印可される。供給ローラ６には−３３０Ｖの直流バイアスが印可される。
【０３０３】
２はエピクロルヒドリンゴムよりなる外径１２ｍｍの帯電ローラで直流バイアス−１ｋＶが印加される。感光体１表面を−４５０Ｖに帯電する。８はクリーナ、９は廃トナーボックス、７はトナーである。
【０３０４】
紙搬送は転写ユニット１７の下方から搬送され、転写ベルト１２と第２転写ローラ１４との圧接されたニップ部に紙給送ローラ（図示せず）により紙１９が送られてくるように、紙搬送路が形成されている。
【０３０５】
転写ベルト１２上のトナーは第２転写ローラ１４に印加された＋１３００Ｖにより紙１９に転写され、定着ローラ２０１、加圧ローラ２０２、定着ベルト２０３、加熱媒体ローラ２０４、インダクションヒータ部２０５から構成される定着部に搬送され、ここで定着される。
【０３０６】
図８にその定着プロセス図を示す。定着ローラ２０１とヒートローラ２０４との間にベルト２０３がかけられている。定着ローラ２０１と加圧ローラ２０２との間に所定の加重がかけられており、ベルト２０３と加圧ローラ２０２との間でニップが形成される。ヒートローラ２０４の外部周面にはフェライトコア２０６、とコイル２０７よりなるインダクションヒータ部２０５が設けられ、外面には温度センサー２０８が配置されている。
【０３０７】
ベルトは３０μｍのＮｉを基体としてその上にシリコーンゴムを１５０μｍ、さらにその上にＰＦＡチューブ３０μｍの重ねあわせた構成である。
【０３０８】
加圧ローラ２０２は加圧バネ２０９により定着ローラ２０１に押しつけられている。トナー２１０を有する記録材２１１は、案内板２１２に沿って動く。
【０３０９】
定着部材としての定着ローラ２０１は、長さが２５０ｍｍ、外径が１４ｍｍ、厚さ１ｍｍのアルミニウム製中空ローラ芯金２１３の表面に、ＪＩＳ規格によるゴム硬度（ＪＩＳ−Ａ）が２０度のシリコーンゴムからなる厚さ３ｍｍの弾性層２１４を設けている。この上にシリコーンゴム層２１５が３ｍｍの厚みで形成され外径が約２０ｍｍとなっている。図示しない駆動モータから駆動力を受けて１００ｍｍ／ｓで回転する。
【０３１０】
ヒートローラ２０４は肉厚１ｍｍ、外径２０ｍｍの中空パイプからなっている。定着ローラ表面温度はサーミスタを用いて表面温度１７０度に制御した。
【０３１１】
加圧部材としての加圧ローラ２０２は、長さが２５０ｍｍ、外径２０ｍｍである。これは外径１６ｍｍ、厚さ１ｍｍのアルミニウムからなる中空ローラ芯金２１６の表面にＪＩＳ規格によるゴム硬度（ＪＩＳ−Ａ）が５５度のシリコーンゴムからなる厚さ２ｍｍの弾性層２１７を設けている。この加圧ローラ２０２は、回転可能に設置されており、片側１４７Ｎのバネ加重のバネ２０９によって定着ローラ２０１との間で幅５．０ｍｍのニップ幅を形成している。
【０３１２】
以下、動作について説明する。フルカラーモードではＹ，Ｍ，Ｃ，Ｋのすべての第一転写ローラ１０が押し上げられ、転写ベルト１２を介して像形成ユニットの感光体１を押圧している。この時第一転写ローラには＋８００Ｖの直流バイアスが印可される。画像信号がレーザ光３から送られ、帯電ローラ２により表面が帯電された感光体１に入射し、静電潜像が形成される。感光体１と接触し反対方向に回転する現像ローラ４上のトナー７が感光体１に形成された静電潜像を顕像化する。
【０３１３】
このとき像形成ユニット１８Ｙの像形成の速度（感光体の周速に等しい１００ｍｍ／ｓ）と転写ベルト１２の移動速度は感光体速度が転写ベルト速度よりも０．５〜１．５％遅くなるように設定されている。
【０３１４】
像形成工程により、Ｙの信号光３Ｙが像形成ユニット１８Ｙに入力され、Ｙトナーによる像形成が行われる。像形成と同時に第１転写ローラ１０Ｙの作用で、Ｙトナー像が感光体１Ｙから転写ベルト１２に転写される。このとき第１転写ローラ１０Ｙには＋８００Ｖの直流電圧を印加した。
【０３１５】
第１色（Ｙ）第一転写と第２色（Ｍ）第一転写間のタイムラグを持たせて、Ｍの信号光３Ｍが像形成ユニット１８Ｍに入力され、Ｍトナーによる像形成が行われ、像形成と同時に第１転写ローラ１０Ｍの作用で、Ｍトナー像が感光体１Ｍから転写ベルト１２に転写される。このとき第一色（Ｙ）トナーが形成されている上にＭトナーが転写される。同様にＣ（シアン）、Ｋ（ブラック）トナーによる像形成が行われ、像形成と同時に第１転写ローラ１０Ｃ、１０Ｋの作用で、ＹＭＣＫトナー像が転写ベルト１２上に形成される。いわゆるタンデム方式と呼ばれる方式である。
【０３１６】
転写ベルト１２上には４色のトナー像が位置的に合致して重ね合わされカラー像が形成された。最後のＫトナー像の転写後、４色のトナー像はタイミングを合せて給紙カセット（図示せず）から送られる紙１９に、第２転写ローラ１４の作用で一括転写される。このとき転写ローラ１３は接地し、第２転写ローラ１４には＋１．３ｋＶの直流電圧を印加した。紙に転写されたトナー像は定着ローラ対２０１・２０２により定着された。紙はその後排出ローラ対（図示せず）を経て装置外に排出された。中間転写ベルト１２上に残った転写残りのトナーは、クリーニングブレード１６の作用で清掃され次の像形成に備えた。
【０３１７】
図７にはベルトへの一次転写を行わずに紙搬送ベルト１７上に紙１９を搬送させ，ＯＰＣ上のトナーを直接転写させるタンデム方式を示す。
【０３１８】
（表１５）に図６の電子写真装置により、画像出しを行った結果を示す。（表１６）ではトナーが３色重なったフルカラー画像における文字部での転写不良の状態、及び定着での定着ベルトへの紙の巻き付き性を評価した。
【０３１９】
【表１５】

【０３２０】
【表１６】

【０３２１】
図６に示す画像形成装置により、前記のように製造したトナーを用いて画像出しを行ったところ、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で、１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像が得られ、画像濃度１．３以上の高濃度の画像が得られた。また、非画像部の地かぶりも発生していなかった。更に、Ａ４用紙１万枚の長期耐久テストにおいても、流動性、画像濃度とも変化が少なく安定した特性を示した。また現像時の全面ベタ画像を取ったときの均一性も良好であった。現像メモリーも発生していない。連続使用時においても、縦筋の異常画像は発生しなかった。また転写においても中抜けは実用上問題ないレベルであり、転写効率は９８％程度を示した。また、感光体、転写ベルトへのトナーのフィルミングも実用上問題ないレベルであった。転写ベルトのクリーニング不良も未発生であった。また定着時のトナーの乱れやトナー飛びもほとんど生じていない。またクリーニングブレード８を使用せずに転写時の残トナーをこのまま現像での回収を行うクリーナプロセスにおいても、回収がスムーズに行え、前画像の履歴が残ることがなかった。また３色の重なったフルカラー画像においても、転写不良は発生せず、定着時において、定着ベルトへの紙の巻き付きは発生しなかった。図７に示す画像形成装置によっても、同様な結果が得られた。
【０３２２】
しかしｔｍ７、ｔｙ７、ｔｃ７、ｔｂ７のトナーは感光体のフィルミングや転写不良や、転写時の文字の飛び散りが発生し、カブリも多く発生した。転写ベルトのフィルミングや、クリーニング不良も発生した。現像時の全面ベタ画像を取ったときに後半部にかすれが生じた。連続使用時に現像ブレードにワックスが融着し、縦筋の異常画像が発生した。３色重ねの画像出力時には定着ベルトへの紙の巻き付きが発生した。定着時にトナー飛びが発生した。
【０３２３】
次に（表１７）にＯＨＰ用紙に付着量１．２ｇ／ｃｍ^２以上のベタ画像をプロセス速度１００ｍｍ／ｓ、オイルを塗布しないベルトを用いた定着装置にて非オフセット性試験を行った。定着ニップ部でＯＨＰのジャムは発生しなかった。普通紙の全面ベタグリーン画像では、オフセットは１２２０００枚目までは全く発生しなかった。シリコーン又はフッ素系の定着ベルトでオイルを塗布せずともベルトの表面劣化現象はみられない。
【０３２４】
透過率と、高温でのオフセット性を評価した。プロセス速度は１００ｍｍ／ｓ、定着温度１８０℃で透過率は分光光度計Ｕ−３２００（日立製作所）で、７００ｎｍの光の透過率を測定した。定着性、耐オフセット性、保存安定性の結果を示す。
【０３２５】
【表１７】

【０３２６】
ＯＨＰ透光性が８０％以上を示しており、また非オフセット温度幅も４０〜６０Ｋとオイルを使用しない定着ローラにおいて良好な定着性を示した。また６０℃、５時間の保存安定性においても凝集はほとんど見られなかった。
【０３２７】
しかしｔｍ７のトナーは貯蔵安定性テストで固まりが生じ、また非オフセット温度域も狭い結果となった。
【０３２８】
【発明の効果】
以上のように、ワックスを添加した特定の小粒径トナーに外添処方を合せることにより、現像性、転写性の両立を図ることができる。さらにはタンデム方式の転写プロセスにおける転写性、オイルレス定着高画質化と転写時の中抜けや飛び散りを防止し、高転写効率を得ることが可能となる。高湿下での長期使用においても、感光体、転写体のフィルミングを防止することができる。転写体のクリーニング性を向上することができる。クリーニングブレード等を使用しないクリーナレスプロセスにおいても転写残トナーの回収がスムーズに行え、前画像の履歴が残らないようにすることができる。さらには、オイルを塗布せずとも、高いＯＨＰ透光性を維持しながらオフセット性を防止するオイルレス定着を実現できる。
【図面の簡単な説明】
【図１】本発明の実施例で使用したトナー溶融混練処理の概略斜視図
【図２】本発明の実施例で使用したトナー溶融混練処理の平面図
【図３】本発明の実施例で使用したトナー溶融混練処理の正面図
【図４】本発明の実施例で使用したトナー溶融混練処理の断面図
【図５】本発明の実施例で使用したトナー粉砕処理の構成図
【図６】本発明の実施例で使用した画像形成装置の構成を示す断面図
【図７】本発明の実施例で使用した画像形成装置の構成を示す断面図
【図８】本発明の実施例で使用した定着ユニットの構成を示す断面図
【符号の説明】
１　感光体
３　レーザ信号光
４　現像ローラ
５　ブレード
１０　第１転写ローラ
１２　転写ベルト
１４　第２転写ローラ
１３　駆動テンションローラ
１７　転写ベルトユニット
１８Ｂ，１８Ｃ，１８Ｍ，１８Ｙ　像形成ユニット
１８　像形成ユニット群
２０１　定着ローラ
２０２　加圧ローラ
２０３　定着ベルト
２０５　インダクションヒータ部
２０６　フェライトコア
２０７　コイル
６０２　ロール（ＲＬ１）
６０３　ロール（ＲＬ２）
６０４　ロール（ＲＬ１）上に巻き付いたトナーの溶融膜
６０５　熱媒体の流入口
６０６　熱媒体の流出口[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a toner used for a copier, a laser printer, a plain paper FAX, a color PPC, a color laser printer, a color FAX, and an image forming apparatus using the toner.
[0002]
[Prior art]
2. Description of the Related Art In recent years, electrophotographic apparatuses are shifting from office use to personal use, and a technology for realizing miniaturization, high speed, high image quality, maintenance-free, and the like is required. Therefore, a cleaner-less process that collects waste toner during development without cleaning the residual toner remaining after transfer, a tandem color process that enables high-speed output of color images, and no use of fixing oil to prevent offset during fixing In addition, oil-less fixing, which achieves both a clear color image having high gloss and high translucency and non-offset properties, is required along with conditions such as good maintainability and low ozone exhaust. These functions must be compatible at the same time, and the improvement of toner properties as well as the process is an important factor.
[0003]
In a color printer, an image carrier (hereinafter, referred to as a photoconductor) is charged by corona discharge using a charging charger, and thereafter, a latent image of each color is irradiated as a light signal on the photoconductor to form an electrostatic latent image. The latent image is developed by developing with a color, for example, yellow toner. Thereafter, the transfer member charged to the opposite polarity to the charge of the yellow toner is brought into contact with the photoconductor, and the yellow toner image formed on the photoconductor is transferred. The photoreceptor is cleaned after removing the toner remaining at the time of transfer, and is then discharged, thereby completing the development and transfer of the first color toner. Thereafter, the same operation as that for the yellow toner is repeated for toners such as magenta and cyan to form a color image by superimposing toner images of each color on a transfer body. A 4-pass color process in which these superimposed toner images are transferred to paper charged to the opposite polarity to the toner has been put to practical use.
[0004]
In addition, a plurality of image forming stations having a charger, a photoconductor, a developing unit, etc. are arranged side by side, and an endless transfer body is brought into contact with the photoconductor to sequentially transfer toner of each color sequentially to the transfer body. A secondary transfer process is performed to form a multilayer transfer color toner image on the transfer body by executing the process, and then collectively transfer the multilayer toner image formed on the transfer body to a transfer medium such as paper or OHP. A tandem color process configured to be executed and a tandem color process for continuously transferring directly to paper or an OHP transfer medium without using a transfer body have been proposed.
[0005]
This method has a feature that a color image can be output at a high speed, but the toner layer of four colors is superimposed on the transfer body, so that the toner layer becomes thick, and a pressure difference between the toner layer having no toner layer and the thin layer is easily generated. For this reason, the "hollow-out" phenomenon in which a part of the image is not transferred and a hole is formed due to the aggregation effect of the toner is likely to occur. Furthermore, if a material having a high toner releasing effect is used for the transfer body in order to reliably clean the residual toner, hollow holes will appear significantly, and the image quality will be significantly reduced. Furthermore, edge development is performed for characters and lines, and the amount of toner is increased, and toner particles are aggregated by pressurization, so that hollow holes are more remarkable. In particular, it appears more remarkably in a high-humidity and high-temperature environment.
[0006]
Further, in order to reduce the size and speed of the machine, it is required that the distance between image forming stations (corresponding to the distance between photoconductors) be shorter and that printing be performed at a higher speed. As a result, for example, the time from the first transfer of the yellow toner to the second transfer of the next magenta toner is extremely short, and the charge relaxation of the transfer body and the charge relaxation of the transferred toner hardly occur. When transferring the magenta toner onto the yellow toner, the magenta toner is repelled by the charge action of the yellow toner, causing image disturbance due to scattering of the toner image, a decrease in transfer efficiency, and a problem of missing characters during transfer. Occurs.
[0007]
Further, in the configuration using the intermediate transfer member, when the final toner of the fourth color is primary-transferred and then collectively secondary-transferred to paper or the like, toner images are disturbed due to repulsion due to mutual charge of the toner.
[0008]
In addition, in order to improve the dot reproducibility in transfer, a configuration in which the resistance of the transfer body is set to a high resistance causes a poor transfer of a solid image and a hollow character.
[0009]
Further, it is desired to reduce the toner particle size in order to improve the resolution. However, simply reducing the particle size of the toner does not sufficiently improve the image quality, and also leads to a decrease in productivity and an increase in production cost. To improve the image quality, the sharpness of the cut on the coarse powder side is strongly affected by the amount of particles on the fine powder side. In terms of productivity, it is necessary to improve the method of pulverization to reduce the particle size without reducing the production amount. Particularly, in order to realize an oil-less fixing color toner described later, a configuration in which wax is added is adopted. The problem with this configuration is that the cohesiveness of the toner is strong due to the wax, and the toner is conveyed to the pulverizing area without being loosened, so it is difficult to pulverize the small particle size, and it is necessary to cut sharply on the coarse powder side. It becomes difficult. In addition, the air adheres strongly to the piping in the air conveyance, which is also a factor that lowers productivity and crushability.
[0010]
In the above-described transfer configuration in which the distance between the image forming stations is shorter, the toner is repelled by the charge action of the toner, and the image is disturbed by scattering of the toner image, the transfer efficiency is reduced, and characters are lost during transfer. It will be easier.
[0011]
Further, in order to enable oilless fixing without using oil at the time of fixing described later, a toner composition in which a release agent such as a wax is added to a sharp melt resin has a characteristic that the charge retention is strong and the toner has a strong cohesiveness. As a result, the tendency of toner image disturbance and transfer failure occurs more remarkably, making it difficult to achieve both transfer and fixing. Further, in a toner to which a wax having a polar group is added in order to enhance dispersibility in a polyester resin, cohesiveness becomes stronger, and it is extremely difficult to achieve both oilless fixing and transferability.
[0012]
In the fixing process, in a color image, it is necessary to melt and mix the color toner to enhance the light transmission. When the toner is defectively fused, light is scattered on the surface or inside of the toner image, so that the original color tone of the toner dye is deteriorated, and light does not enter the lower layer in the overlapped portion, so that color reproducibility is reduced. Therefore, it is a necessary condition that the toner has a perfect melting property and has a light transmitting property that does not hinder the color tone. In addition, the need for optical transparency on OHP paper is increasing due to an increase in opportunities for presentation in color.
[0013]
However, in a resin composition having a melting property of sharp melt due to light transmittance, offset resistance is reduced and offset occurs due to adhesion to the fixing roller surface, so a large amount of oil or the like must be applied to the fixing roller. In addition, the handling and the configuration of the equipment become complicated. Therefore, an oil-less color fixing configuration that does not require oil is required.
[0014]
Further, a fluorine-based material is used for improving the releasing property and durability of the fixing roller and the belt. However, since the unfixed toner image electrostatically repels the fixing roller before entering the fixing unit, image disorder is likely to occur. Conversely, before the toner enters the fixing nip, the toner may fly on the fixing roller to cause a halftone offset. In particular, in a configuration in which the release oil is not applied, the influence of the charging property of the roller is likely to occur. Further, in the case of a toner to which a release agent is added for the purpose of improving the offset property, a flaw in the fixing roller is apt to occur due to a state of poor dispersion of the internal additive, which causes a vertical streak of an image.
[0015]
As is well known, a toner for electrostatic charge development used in an electrophotographic method generally comprises a resin component as a binder resin, a coloring component comprising a pigment or a dye, a plasticizer, a charge control agent, and, if necessary, It is composed of an additive component such as a release agent. As the resin component, a natural or synthetic resin is used alone or in a suitable mixture.
[0016]
Then, the above additives are preliminarily mixed at an appropriate ratio, heated and kneaded by heat melting, finely pulverized by an airflow collision plate system, and classified into fine powder to complete a toner base. There is also a method in which a toner matrix is prepared by a chemical polymerization method. Thereafter, an external additive such as hydrophobic silica is externally added to the toner matrix to complete the toner. In the one-component development, a two-component developer is obtained by mixing the toner and a carrier composed of magnetic particles, although the toner is composed of only the toner.
[0017]
Japanese Patent Application Laid-Open No. Hei 2-271364 discloses an external additive introducing means for introducing an external additive into a high-speed gas flow, and a collision plate provided in a flow path of the high-speed gas flow on which the pulverized raw material and the external additive are placed. The effect that the homogenous mixing of the pulverized body and the additive component can be easily performed by the configuration in which the pulverized raw material collides with the impingement plate to be pulverized and the external additive is collided with the pulverized raw material near the impingement plate and mixed. Is disclosed. However, this configuration is intended for homogeneous mixing with the added components, and is intended for the purpose of the present invention to reduce the particle size, sharp-cut the coarse powder side, and further crush production in the configuration of oil-less fixing toner to which wax is added. No suggestion has been made regarding gender improvement. In particular, in a pulverizer using a collision plate method in which a toner to which a wax is added at a high concentration is added, the wax is excessively exposed to the toner surface, which causes filming to the photoconductor.
[0018]
Japanese Patent Application Laid-Open No. 6-89045 discloses that a coarse particle for toner is subjected to an intermediate pulverization process, and the resulting intermediate particles for toner having an average particle diameter of 10 to 50 μm and fine particles for modification having an average particle diameter of 1 μm or less are mixed. The body powder is subjected to friction pulverization treatment by a mechanical pulverizer to obtain a toner in which the modifying particles are fixed to the toner particles. There is disclosed an effect that a toner having excellent durability can be manufactured with high efficiency. However, there is no suggestion regarding the reduction of the particle size, the sharp cut property of the coarse powder side, and the improvement of the pulverization productivity in the configuration of the oil-less fixing toner to which the wax is added for the purpose of the present application.
[0019]
Further, a configuration is disclosed in which the image quality can be improved by a toner that specifies the particle size distribution of the toner. As means for realizing the particle size distribution configuration, for example, coarse powder and fine powder are simultaneously cut by an elbow jet classifier. Means are shown. However, there is no disclosure of the content of the means for achieving a predetermined particle size distribution in the pulverizing step, and there is a problem that the production yield is reduced in a configuration in which the particle size is reduced through the classification of coarse powder. In addition, a toner that achieves oilless fixing has a configuration in which the resin has a high viscosity in order to prevent high-temperature offset, and further pulverization efficiency is desired.
[0020]
As the releasing agent and wax to be added, Japanese Patent Application Laid-Open No. 266372/1990 discloses the use of carnauba wax and / or montan ester wax having a free fatty acid type and oxidized rice wax having an acid value of 10 to 30. JP-A-281748 discloses a vinyl copolymer which is polymerized in the presence of a natural gas-based Fischer-Tropsch wax at a melting point of 85 to 100 ° C, and JP-A-10-327196 discloses a polyhydric alcohol component and a dicarboxylic acid and It is disclosed that polycondensation is carried out with a polyvalent carboxylic acid compound having a valency of not less than 0.1 to 3 parts by weight when the average dispersion particle diameter of the release agent is 0.1 to 3 μm and the particle diameter of the external additive is 4 to 200 nm. Have been. JP-A-5-333584 discloses that the fixing property is improved by a constitution containing a fluorine-modified polyolefin resin such as polypropylene modified with an organic fluorine compound such as perfluorooctyl methacrylate. . In JP-A-5-188632, the non-offset property at the time of fixing is improved by blending a softening point of 80 to 140 ° C., a low molecular weight polyolefin containing fluorine, and a molten mixture of the low molecular weight olefin and polytetrafluoroethylene. The contents to be carried out are disclosed, and contents effective for improving the fixing property are described.
[0021]
JP-A-59-148067 discloses that an unsaturated ethylene polymer having a low molecular weight and a high molecular weight portion in a resin, a low molecular weight peak value and Mw / Mn is used, and a softening point is specified. A toner containing the polyolefin is disclosed. It is stated that the fixing property and the anti-offset property are ensured by this. JP-A-56-158340 discloses a toner mainly composed of a resin composed of a specific low-molecular-weight polymer component and a high-molecular-weight polymer component. The purpose is to ensure the fixing property with a low molecular weight component and the offset resistance with a high molecular weight component. JP-A-58-223155 discloses a resin comprising an unsaturated ethylene polymer having a maximum value in the molecular weight range of 1,000 to 10,000 and 200,000 to 1,000,000 and having a Mw / Mn of 10 to 40 and a specific softening property. A toner containing a polyolefin having a dot is disclosed. It is used for the purpose of securing the fixing property by the low molecular weight component and the offset resistance by the high molecular weight component and the polyolefin.
[0022]
Further, JP-A-63-56659 and JP-A-2000-98661 disclose toners relating to polyester resins and disclose that good fixability can be obtained.
[0023]
Examples of the charge control agent for imparting chargeability to the toner include benzyl acid derivatives described in JP-A-2-22167, JP-A-7-84409, JP-A-5-72812, and JP-A-5-165257. A toner using a metal salt is disclosed. JP-A-53-127726, JP-A-55-42752, JP-A-7-2171097, and the like disclose toners using a metal salt of a salicylic acid derivative.
[0024]
However, if the melt viscosity of the binder resin is reduced or a resin with a low molecular weight is used to increase the fixing strength, the pulverizability becomes easy. So-called spent that sticks easily occurs. The stress resistance of the developer decreases. Further, an offset in which toner adheres to the heat roller at the time of fixing tends to occur. In addition, blocking occurs in which the toners fuse together during long-term storage.
[0025]
For a resin composition in which a high molecular weight component and a low molecular weight component are blended or copolymerized, a low melting point release agent, such as polyethylene or polypropylene wax, improves the releasability from the heat roller during fixing. It is added for the purpose of increasing the offset resistance. However, it is difficult for these release agents to improve the dispersibility in the binder resin, and the reverse polarity toner is easily generated due to poor dispersion, and fogging to the non-image area occurs. In addition, an image chipping, such as a brush scrape, occurs at the rear end of the solid black image area, thereby deteriorating the image quality. There is also a problem of filming contamination of the carrier, the photoconductor, and the developing sleeve.
[0026]
Also, when using a toner that uses a low melting point release agent and a low softening resin to enhance the gloss and translucency of a color image, vertical streaks on the developing roller during development and transfer Improving dispersibility due to poor body cleaning and filming, poor scraping of the transfer body cleaning roller, reduces the releasability effect, narrows the non-offset area, and makes it difficult to achieve compatibility. .
[0027]
In addition, a contact type one-component developing method in which an elastic blade for regulating a toner layer is used in contact with a developing roller such as silicone or urethane and a supply roller such as urethane for supplying toner to the developing roller is used, a low melting point is used. In the toner to which the release agent is added, the rising property of the charge is deteriorated, and the charge maintaining property is deteriorated during long-term continuous use. In addition, the use of the toner to which the above-mentioned low melting point release agent is added gradually causes vertical streaks on the developing roller after the use of thousands of sheets, and causes image defects such as white spots and black streaks. This is considered to be caused by damage to the developing roller due to poor dispersion of the release agent, fusion to the blade, and agglomeration due to friction between the supply roller and the developing roller.
[0028]
It is important to realize a cleaner-less process without a cleaning process from the miniaturization of equipment and resource saving. After transferring the visualized toner of the electrostatic latent image formed on the photoreceptor to a transfer body or paper by a transfer unit, the toner remaining on the photoreceptor is usually cleaned by a means such as a blade or a fur brush. To collect and become waste toner. At this time, a cleanerless process performs the next charging, exposing, and developing processes without having this cleaning process step. Although a certain amount of the transfer residual toner remains on the photoreceptor, if the residual toner in the non-image area is collected and returned to the development in the next development process, no image problem occurs.
[0029]
In the case of outputting a color image, in the transfer step of superimposing the color images, the toner of the previous color is reversely transferred to the photoreceptor, which may become an abnormal image as a memory. Therefore, it is important to take measures against the residual toner and the reversely transferred toner.
[0030]
[Problems to be solved by the invention]
As described above, the toner must satisfy the above-mentioned problems comprehensively. In an oilless fixing toner that does not use oil for the fixing roller, the toner itself has the oil function used for the fixing member. Therefore, it is necessary to achieve oilless fixing by using a release agent such as wax in the toner, maintain transferability even in a tandem type color process, and satisfy the cleanerless process. is there. Further, it is necessary to reduce toner particle size without lowering productivity in order to realize high resolution and to sharpen the particle size distribution in order to improve image quality.
[0031]
In view of the above problems, the present invention reduces the toner particle size to improve image quality, arranges an image forming station having a plurality of photoconductors and a developing unit side by side, and sequentially transfers toner of each color sequentially to a transfer medium. In the tandem color process that executes the process, it is possible to prevent dropout and scattering at the time of transfer, obtain high transfer efficiency, avoid filming on the transfer body, etc., and prevent fusion to the transfer body and cleaning means. It is an object to provide a toner and an image forming apparatus.
[0032]
It is another object of the present invention to provide a full-color electrophotographic toner and an image forming apparatus that exhibit high translucency and gloss by oilless fixing without applying oil to a fixing roller. Filming on developing rollers, doctor blades, transfer bodies, etc. can be avoided even with color toners using low-melting sharp-melt resins, and photoconductors, transfer bodies, etc. An object of the present invention is to provide a toner and an image forming apparatus that can prevent filming.
[0033]
Also, even when used in the one-component developing method, the developing roller does not have vertical streaks, does not cause thermal fusion or aggregation of the toner on the layer regulating blade or the developing roller even when used continuously, and suppresses a decrease in the charge amount. It is another object of the present invention to provide a toner and an image forming apparatus capable of improving the dispersibility of an additive and maintaining stable developability without deteriorating resin characteristics.
[0034]
In addition, the present invention provides a toner and an image forming apparatus that can achieve high transfer efficiency even in a cleanerless process, do not cause a decrease in charge amount and fluidity, facilitate recovery in development, do not generate a memory, and enable a cleanerless process. The purpose is to do.
[0035]
In addition, in a toner to which a release agent such as a low-melting point wax is added, contamination of the photoreceptor, carrier, developing roller, and transfer body due to bleeding of wax or the like can be prevented. An object of the present invention is to provide a toner and an image forming apparatus that can achieve long-term stabilization.
[0036]
Also, in the fixing process using a belt, in the belt fixing using a roller having a low fixing pressure and a long fixing nip and having a large curvature, the non-wrapping property of the paper on the belt is improved, and furthermore, the belt and the belt are fixed. An object of the present invention is to provide a toner and an image forming apparatus that can prevent chipping of an image portion that occurs when paper is separated, and that can achieve both development and transfer properties.
[0037]
[Means for Solving the Problems]
In view of the above problems, in the configuration according to the present invention, the toner containing at least the binder resin, the colorant, and the wax has a volume average particle diameter of 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution. Particle size containing 60% by number or more, content of 3.17 μm or less in the number distribution being 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm being 35% by volume or less. The toner is obtained by externally adding 2.5 to 5.3 parts by weight of an inorganic fine powder having a distribution configuration and an average particle diameter of 6 nm to 120 nm with respect to 100 parts by weight of the toner base particles.
[0038]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. % To 3.17 μm or less in the number distribution, 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm in 30% by volume or less. And 2.5 to 5.3 parts by weight of an inorganic fine powder having an average particle diameter of 6 nm to 120 nm with respect to 100 parts by weight of the toner base particles. This is a toner that has undergone external addition processing.
[0039]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. Particle size distribution composition in which the content of 3.17 μm or less in the number distribution is 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained in 35% by volume or less. And 1.0 to 2.5 parts by weight of the inorganic fine powder having an average particle diameter of 6 nm to 20 nm with respect to 100 parts by weight of the toner base particles. 1.5 to 2.8 parts by weight with respect to parts by weight of the toner.
[0040]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. % To 3.17 μm or less in the number distribution, 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm in 30% by volume or less. Of the inorganic fine powder having an average particle diameter of 6 nm to 20 nm with respect to 100 parts by weight of the toner base particles. The toner is obtained by externally adding at least 1.5 to 2.8 parts by weight of an inorganic fine powder having a thickness of 30 nm to 120 nm with respect to 100 parts by weight of the toner base particles.
[0041]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. Particle size distribution composition in which the content of 3.17 μm or less in the number distribution is 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained in 35% by volume or less. And an inorganic fine powder having an average particle size of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% is used in an amount of 1.0 to 2.5 parts by weight based on 100 parts by weight of the toner base particles. Is a toner obtained by externally adding at least 1.5 to 2.8 parts by weight of an inorganic fine powder having a loss on ignition of 0.1 to 23 wt% with respect to 100 parts by weight of toner base particles.
[0042]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. % To 3.17 μm or less in the number distribution, 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm in 30% by volume or less. 100% by weight of the inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% in a particle size distribution configuration in which the content of 8 μm or more is 1% by volume or less. Parts by weight, and an inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt%, based on 100 parts by weight of the toner base particles. 2.8 parts by weight This is at least an externally added toner.
[0043]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. Particle size distribution composition in which the content of 3.17 μm or less in the number distribution is 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained in 35% by volume or less. And 1.8 to 4 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 to 120 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles. A toner obtained by externally adding at least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having a loss of 6 to 120 nm and an ignition loss of 0.1 to 23 wt% with respect to 100 parts by weight of toner base particles. .
[0044]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. % To 3.17 μm or less in the number distribution, 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm in 30% by volume or less. The toner base particles have a particle size distribution of not less than 8 μm and not more than 1% by volume, and a negatively chargeable inorganic fine powder having an average particle size of 6 nm to 120 nm and a loss on ignition of 0.5 to 25 wt%. 1.8 to 4 parts by weight based on 100 parts by weight, and a positively chargeable inorganic fine powder having an average particle size of 6 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% is added to 100 parts by weight of the toner base particles. 0.5-1.5 Parts by weight of the toner.
[0045]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. Particle size distribution composition in which the content of 3.17 μm or less in the number distribution is 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained in 35% by volume or less. And 0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles. 1.2 to 2.0 parts by weight of a negatively chargeable inorganic fine powder having a diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles, and an average particle diameter of 6 nm to 20 nm ignition loss is 0.5 ~ The positively chargeable inorganic fine powder is 5 wt% with respect to 100 parts by weight of the toner base particles are toner least externally added and 0.5 to 1.5 parts by weight.
[0046]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. % To 3.17 μm or less in the number distribution, 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm in 30% by volume or less. A negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% in a toner base 0.8 to 2 parts by weight based on 100 parts by weight of the particles, and a negatively chargeable inorganic fine powder having an average particle size of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles. 1.2-2.0 And at least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles. Externally added toner.
[0047]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. Particle size distribution composition in which the content of 3.17 μm or less in the number distribution is 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained in 35% by volume or less. And 0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles. 1.2 to 2.0 parts by weight of a negatively chargeable inorganic fine powder having a diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles, and an average particle diameter of 30 nm to No loss on ignition at 120 nm The positively chargeable inorganic fine powder is 1～23Wt% with respect to 100 parts by weight of the toner base particles are toner and 0.5 to 1.5 parts by weight of externally added to externally added.
[0048]
Further, in the configuration according to the present invention, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60. % To 3.17 μm or less in the number distribution, 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm in 30% by volume or less. A negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% in a toner base 0.8 to 2 parts by weight based on 100 parts by weight of the particles, and a negatively chargeable inorganic fine powder having an average particle size of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles. 1.2-2.0 Parts by weight and 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles. A toner characterized in that an external addition process has been performed.
[0049]
BEST MODE FOR CARRYING OUT THE INVENTION
Digital high image quality, high-definition color reproducibility colorization, high transparency and anti-offset compatibility can be achieved without using offset prevention oil on the fixing roller. It is intended to prevent generation of vertical streaks due to blade fusion, and to realize both stable transferability in a cleanerless process and a tandem color process.
[0050]
As the wax to be added to the toner of the present embodiment, a wax having an iodine value of 25 or less and a saponification value of 30 to 300 is added by 1 to 20 parts by weight based on 100 parts by weight of the binder resin. The repulsion due to the charge action of the toner at the time of the multi-layer transfer is alleviated, so that the transfer efficiency can be reduced, the character dropout during the transfer, and the reverse transfer can be suppressed. More preferably, the binder resin has an acid value of 1 to 40 mgKOH / g.
[0051]
It is preferable to add 1 to 20 parts by weight based on 100 parts by weight of the binder resin. If the amount is less than 0.1 part by weight, the effect of improving fixability cannot be obtained, and if it is more than 20 parts by weight, there is a problem in storage stability.
[0052]
If the iodine value is greater than 25, the repulsion due to the charge action of the toner during the multi-layer transfer in the primary transfer is less likely to be reduced. It has great environmental dependence and changes in the chargeability of the material during long-term continuous use, which hinders image stability. If the saponification value is less than 30, the presence of unsaponifiables and hydrocarbons increases, causing photoreceptor filming and deterioration of chargeability. In addition, the dispersibility with the charge control agent becomes poor, which causes filming, fusion, and a decrease in chargeability during continuous use. If it is larger than 300, the dispersibility of the wax in the resin deteriorates, and the repulsion due to the charge action of the toner is hardly alleviated. Further, fog and toner scattering increase. If the resin acid value is less than 1 mgKOH / g, the repulsion due to the charge action of the toner during multi-layer transfer of the toner is less likely to be reduced. If the resin acid value is greater than 40 mgKOH / g, the environmental resistance will deteriorate and the fog will increase. In particular, the transferability under low humidity is apt to be reduced. At this time, the transferability can be maintained by using together with an external additive.
[0053]
Those having a melting point of 50 to 100 ° C by the DSC method are preferred. More preferably, the iodine value is 15 or less, the saponification value is 50 to 250, and the melting point according to the DSC method is 55 to 90 ° C. More preferably, the iodine value is 5 or less, the saponification value is 70 to 200, and the melting point according to the DSC method is 60 to 200. It is 85 ° C.
[0054]
Further, a material having a volume increase rate of 2 to 30% at a change of 10 ° C. at a temperature equal to or higher than the melting point is preferable. When it changes from a solid to a liquid and expands rapidly, when it is melted by the heat of fixing, the adhesion between the toners is further strengthened, the fixing properties are improved, and the releasability from the fixing roller is improved and the resistance is improved. The offset property is also improved. If it is smaller than 2, the effect is small, and if it is larger than 30, the dispersibility at the time of kneading decreases.
[0055]
The loss on heating of the wax at 220 ° C. is preferably 8% by weight or less. When the weight loss on heating is more than 8% by weight, the resin remains in the binder resin during the heating and kneading, greatly lowering the glass transition point of the binder resin and impairing the storage stability of the toner. This adversely affects the developing characteristics and causes fogging and filming of the intermediate transfer member of the photoconductor.
[0056]
The wax having an iodine value of 25 or less and a saponification value of 30 to 300 has a molecular weight characteristic in gel permeation chromatography (GPC), a number average molecular weight of 100 to 5,000, a weight average molecular weight of 200 to 10,000, and a weight average molecular weight. The ratio of the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.01 to 8, the ratio of the Z average molecular weight to the number average molecular weight (Z average molecular weight / number average molecular weight) is 1.02 to 10, and the molecular weight is 5 × 10. ² ~ 1 × 10 ⁴ Preferably has at least one maximum molecular weight peak in the region. More preferably, the number average molecular weight is 500 to 4500, the weight average molecular weight is 600 to 9000, the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.01 to 7, and the Z average molecular weight and number average are The molecular weight ratio (Z-average molecular weight / number-average molecular weight) is 1.02 to 9, more preferably the number-average molecular weight is 700 to 4000, the weight-average molecular weight is 800 to 8000, and the ratio of the weight-average molecular weight to the number-average molecular weight (weight-average molecular weight). (Molecular weight / number average molecular weight) is 1.01 to 6, and the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 1.02 to 8.
[0057]
When the number average molecular weight is smaller than 100 and the weight average molecular weight is smaller than 200, storage stability is deteriorated. Maximum molecular weight peak is 5 × 10 ² If it is located in a smaller range, the dispersibility of the charge control agent together with the wax deteriorates. The storage stability of the toner deteriorates, filming occurs on the photoreceptor and the transfer member, vertical stripes on the developing roller, scraping defects on the cleaning roller, and the like occur.
[0058]
The number average molecular weight is greater than 5000, the weight average molecular weight is greater than 10,000, the ratio of weight average molecular weight to number average molecular weight (weight average molecular weight / number average molecular weight) is greater than 8, and the ratio of Z average molecular weight to number average molecular weight (Z (Average molecular weight / number average molecular weight) is greater than 10, and the maximum molecular weight peak is 1 × 10 ⁴ If it is located in a range larger than the region, the releasing effect is weakened, and the fixing properties such as fixing properties and anti-offset properties are reduced.
[0059]
Examples of the wax include meadow foam oil derivatives, carnauba wax, jojoba oil derivatives, wood wax, beeswax, ozokerite, carnauba wax, canderia wax, montan wax, ceresin wax, rice wax, and other natural waxes, and Fischer-Tropsch wax. Are preferred, and one or more of them can be used in combination. In particular, carnauba wax having a melting point of 76 to 90 ° C by a DSC method, candelilla wax having a melting point of 66 to 80 ° C, hydrogenated jojoba oil having a temperature of 64 to 78 ° C, hydrogenated meadowfoam oil having a melting point of 64 to 78 ° C or 74. At least one or two or more waxes selected from the group consisting of rice wax having a temperature of up to 90 ° C are more preferable.
[0060]
The saponification value refers to the number of milligrams of potassium hydroxide KOH required to saponify 1 g of a sample. It is the sum of the acid value and the ester value. To determine the saponification value, saponify the sample in an alcoholic solution of about 0.5N potassium hydroxide and then titrate excess potassium hydroxide with 0.5N hydrochloric acid.
[0061]
The iodine value is a value obtained by converting the amount of halogen absorbed when a halogen is applied to a sample into iodine and expressing the amount in grams per 100 g of the sample. It is the number of grams of iodine absorbed in 100 g of fat, and the larger the value, the higher the degree of unsaturation of the fatty acid in the sample. An alcohol solution of iodine and mercury (II) chloride or a glacial acetic acid solution of iodine chloride is added to a chloroform or carbon tetrachloride solution of the sample, and after standing, iodine remaining without reaction is titrated with a standard solution of sodium thiosulfate to absorb iodine. Calculate the amount.
[0062]
For the measurement of the weight loss by heating, the weight of the sample cell is precisely weighed to 0.1 mg (W1 mg), 10 to 15 mg of the sample is put therein, and precisely weighed to 0.1 mg (W2 mg). The sample cell is set on a differential thermobalance, and measurement is started with the weighing sensitivity set to 5 mg. Temperature control is performed by the following program. After the measurement, the weight loss at the time when the sample temperature reaches 220 ° C. is read from the chart to 0.1 mg (W3 mg). The apparatus is TGD-3000 manufactured by Vacuum Riko, a heating rate of 10 ° C./min, a maximum temperature of 220 ° C., a holding time of 1 min, and a heating loss (%) = W3 / (W2−W1) × 100. .
[0063]
Meadowfoam oil derivatives include meadowfoam oil fatty acids, metal salts of meadowfoam oil fatty acids, meadowfoam fatty acid esters, hydrogenated meadowfoam oil, meadowfoam oil amide, homomeadowfoam oil amide, meadowfoam oil triester, epoxy Preferred materials are a maleic acid derivative of a modified meadowfoam oil, an isocyanate polymer of a meadowfoam oil fatty acid polyhydric alcohol ester, and a halogenated modified meadowfoam oil. These can be used alone or in combination of two or more.
[0064]
Meadowfoam oil fatty acids obtained by hydrolyzing meadowfoam oil consist of fatty acids having 18 to 22 carbon atoms. As the metal salt, metal salts such as sodium, potassium, calcium, magnesium, barium, zinc, lead, manganese, iron, nickel, cobalt, and aluminum can be used.
[0065]
Meadowfoam oil fatty acid esters include, for example, esters such as methyl, ethyl, butyl and glycerin, pentaerythritol, polypropylene glycol and trimethylolpropane, and particularly, meadowfoam oil fatty acid pentaerythritol monoester, meadowfoam oil fatty acid pentaerythritol triester Esters, meadowfoam oil fatty acid trimethylolpropane esters and the like are preferred.
[0066]
Further, an esterification reaction product of a meadowfoam oil fatty acid with a polyhydric alcohol such as glycerin, pentaerythritol, and trimethylolpropane may be used to prepare a mixture of tolylene diisocyanate (TDI), diphenylmethane-4,4′-diisocyanate (MDI), and the like. Isocyanate polymer of meadowfoam oil fatty acid polyhydric alcohol ester obtained by crosslinking with isocyanate can also be preferably used.
[0067]
Hydrogenated meadowfoam oil is obtained by hydrogenating meadowfoam oil to convert unsaturated bonds into saturated bonds.
[0068]
Meadowfoam oil amide is obtained by hydrolyzing meadowfoam oil and then esterifying it into a fatty acid methyl ester, and then reacting with a mixture of concentrated aqueous ammonia and ammonium chloride. Further, by adding hydrogen thereto, the melting point can be adjusted. It is also possible to hydrogenate before hydrolysis. A product with a melting point of 75-120 ° C. is obtained. The homomeadowfoam oil amide is obtained by subjecting meadowfoam oil to hydrolysis and reduction to give an alcohol, followed by nitrile.
[0069]
Jojoba oil derivatives include jojoba oil fatty acids, metal salts of jojoba oil fatty acids, jojoba oil fatty acid esters, hydrogenated jojoba oil, jojoba oil amides, homojojoba oil amides, jojoba oil triesters, maleic acid derivatives of epoxidized jojoba oil, jojoba Isocyanate polymer of oil fatty acid polyhydric alcohol ester and halogenated modified jojoba oil are preferred materials. These can be used alone or in combination of two or more.
[0070]
Jojoba oil fatty acids obtained by saponifying and decomposing jojoba oil consist of fatty acids having 18 to 22 carbon atoms. As the metal salt, metal salts such as sodium, potassium, calcium, magnesium, barium, zinc, lead, manganese, iron, nickel, cobalt, and aluminum can be used.
[0071]
Examples of the jojoba oil fatty acid ester include esters such as methyl, ethyl, butyl, glycerin, pentaerythritol, polypropylene glycol, and trimethylolpropane.In particular, jojoba oil fatty acid pentaerythritol monoester, jojoba oil fatty acid pentaerythritol triester, jojoba Preferred are fatty acid trimethylolpropane esters and the like.
[0072]
Further, an esterification reaction product of jojoba oil fatty acid and a polyhydric alcohol such as glycerin, pentaerythritol, and trimethylolpropane may be prepared by converting tolylene diisocyanate (TDI), diphenylmethane-4,4′-dicissocyanate (MDI), or the like. An isocyanate polymer of a jojoba fatty acid polyhydric alcohol ester obtained by crosslinking with an isocyanate is also preferably used.
[0073]
Hydrogenated jojoba oil is obtained by hydrogenating jojoba oil to convert unsaturated bonds into saturated bonds.
[0074]
Jojoba oil amide is obtained by hydrolyzing jojoba oil and then esterifying it into fatty acid methyl esters, and then reacting with a mixture of concentrated aqueous ammonia and ammonium chloride. Further, by adding hydrogen thereto, the melting point can be adjusted. It is also possible to hydrogenate before hydrolysis. A product with a melting point of 75-120 ° C. is obtained. Homojojoba oil amide is obtained by subjecting jojoba oil to hydrolysis and reduction to give an alcohol, followed by nitrile.
[0075]
Materials such as derivatives of hydroxystearic acid, glycerin fatty acid esters, glycol fatty acid esters, and polyhydric alcohol fatty acid esters such as sorbitan fatty acid esters are preferable, and one or a combination of two or more thereof can be used.
[0076]
Derivatives of hydroxystearic acid include methyl 12-hydroxystearate, butyl 12-hydroxystearate, propylene glycol = mono 12-hydroxystearate, glycerin = mono 12-hydroxystearate, and ethylene glycol = mono 12-hydroxystearate Is a suitable material. It has the effect of preventing paper wrapping and the effect of belt filming in oilless fixing.
[0077]
Preferred examples of glycerin fatty acid esters include glycerin monotristearate, glycerin docosanoate, and the like. It has the effect of alleviating the cold offset property at low temperature in oilless fixing and the effect of preventing a decrease in transfer property.
[0078]
Preferred examples of the glycol fatty acid ester include propylene glycol fatty acid esters such as propylene glycol monopalmitate and propylene glycol monostearate, and ethylene glycol fatty acid esters such as ethylene glycol monostearate. In addition to the oilless fixability, it has the effect of improving the slip in development and preventing fusing.
[0079]
Suitable sorbitan fatty acid esters are sorbitan monopalmitate, sorbitan monostearate, and sorbitan monotristearate. Further, materials such as stearic acid ester of pentaerythritol and mixed esters of adipic acid and stearic acid or oleic acid are preferable, and one or more kinds of them can be used in combination. It has the effect of preventing paper wrapping and the effect of belt filming in oilless fixing.
[0080]
In this embodiment, an aliphatic amide wax is internally added to the polyester resin. Thereby, the translucency in a color image can be greatly improved. In particular, the smoothness of the surface of the fixed image is promoted, and a high-quality color image can be obtained. Furthermore, it is possible to prevent the copy paper from being wound around the fixing roller during fixing, to achieve both light transmissivity and anti-offset properties, and to prevent dropout during transfer.
[0081]
Examples of the aliphatic amide wax include those having 16 to 16 carbon atoms such as palmitic acid amide, palmitoleic acid amide, stearic acid amide, oleic acid amide, arachidic acid amide, eicosenoic acid amide, behenic acid amide, erucic acid amide, and ligrinoselic acid amide. Preferred is a saturated or monovalent unsaturated aliphatic amide having 24 and a melting point of 70 to 110 ° C. The temperature is more preferably from 70 to 100 ° C, and still more preferably from 75 to 95 ° C. The addition amount is preferably 0.5 to 20 parts by weight based on 100 parts by weight of the binder resin. If the melting point is lower than 70 ° C., the dispersibility in the resin is reduced, and filming on the photoreceptor tends to occur. When the melting point is higher than 110 ° C., the smoothness of the surface of the fixed image is reduced, and the light transmittance is deteriorated. If the amount is more than 20 parts by weight, the storage stability will deteriorate. If the amount is less than 0.5 parts by weight, the function cannot be exhibited.
[0082]
Furthermore, methylene bis-stearic acid amide, ethylene bis-stearic acid amide, propylene bis-stearic acid amide, butylene bis-stearic acid amide, methylene bis-oleic acid amide, ethylene bis-oleic acid amide, propylene bis-oleic acid amide, butylene bis-oleic acid amide, Methylene bis lauric amide, ethylene bis lauric amide, propylene bis lauric amide, butylene bis lauric amide, methylene bis myristic amide, ethylene bis myristic amide, propylene bis myristic amide, butylene bis myristic amide, methylene bis Palmitic acid amide, ethylene bispalmitic acid amide, propylene bispalmitic acid amide, butylene bispalmitic acid amide, methylene bispalmitry Acid amide, ethylene bispalmitoleic amide, propylene bispalmitoleic amide, butylene bispalmitoleic amide, methylene bis arachidic amide, ethylene bis arachidic amide, propylene bis arachidic amide, butylene bis arachidic amide, methylene Biseicosenamide, ethylenebiseicosenamide, propylenebiseicosenamide, butylenebiseicosenamide, methylenebisbehenamide, ethylenebisbehenamide, propylenebisbehenamide Or alkylenes of saturated or 1-2-valent unsaturated fatty acids such as butylenebisbehenamide, methylenebiserucamide, ethylenebiserucamide, propylenebiserucamide, butylenebiserucamide, etc. Scan fatty acid amide wax are preferable.
[0083]
This makes it possible to improve the translucency of the color image and the resistance to offset to the roller. The addition amount is preferably 1 to 20 parts by weight based on 100 parts by weight of the binder resin. When the melting point is lower than 100 ° C., the effect of offset resistance is reduced. If the melting point is higher than 145 ° C., the dispersibility in the resin will deteriorate, and fog will increase. When the amount is less than 1 part by weight, the function cannot be exhibited, and when the amount is more than 20 parts by weight, fog increases.
[0084]
Further, by constituting a wax of an aliphatic amide type and an alkylenebisfatty acid amide type in a ratio of 3: 7 to 7: 3, it is possible to improve the surface smoothness of a fixed image and to further enhance the high translucency of a color image. And offset resistance can be more excellently achieved. The melting point at that time needs to be higher in the alkylenebisfatty acid amide than in the aliphatic amide. When the melting point of the alkylenebisfatty acid amide is lowered, not only does the offset resistance decrease, but also the resin itself becomes in a softened state, and excessive pulverization at the time of pulverization proceeds, resulting in an increase in fine powder and a reduction in productivity.
[0085]
In particular, since aliphatic amides are low melting point materials, as the compatibilization with the resin progresses, the resin itself is plasticized, and the offset resistance and storage stability are reduced. Getting worse. Therefore, by using in combination with the alkylenebisfatty acid amide, which is a higher melting point material than the aliphatic amide, plasticization of the resin itself is suppressed, and the high translucency and surface smoothness of the aliphatic amide are reduced. Without losing, it is possible to prevent the dropout of the transfer during long-term use, and it is possible to maintain the offset resistance and the storage stability.
[0086]
In the molecular weight distribution by GPC, the weight average molecular weight is 1000 to 6000, the Z average molecular weight is 1500 to 9000, and the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.1 to 3.8. , The ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 1.5 to 6.5, 1 × 10 ³ ~ 3 × 10 ⁴ And a long-chain alkyl alcohol having 5 to 100 carbon atoms having an acid value of 5 to 80 mgKOH / g, a melting point of 80 to 120 ° C, and a penetration at 25 ° C of 4 or less. Waxes obtained by reacting saturated polycarboxylic acids or anhydrides thereof with hydrocarbon waxes, or waxes obtained by reacting long-chain alkylamines with unsaturated polycarboxylic acids or anhydrides thereof and hydrocarbon waxes Or a wax obtained by the reaction of a long-chain fluoroalkyl alcohol with an unsaturated polycarboxylic acid or an anhydride thereof and a hydrocarbon wax is used in a fixing roller or belt in an image in which three layers of color toner are formed on thin paper. This is particularly effective for improving the separation property of paper. It is effective in improving the transparency of OHP without lowering the hot offset property. Further, the addition of the wax can exhibit fixing properties, particularly non-offset properties, high glossiness, and high translucency in oilless fixing, and do not lower the high-temperature storability. Also, even if a fluorine-based or silicone-based member is used for the fixing roller, halftone offset can be prevented. Furthermore, charging stability at the time of continuous use can be obtained, and both fixing property and developing charging stability can be achieved.
[0087]
Furthermore, by improving the state of dispersion when adding this to the binder resin, it is possible to further improve the fixing properties such as releasability and translucency, and the developing properties such as charge stabilization. It is conceivable that the dispersibility of the other internal additives is reduced by the addition of the release agent. However, the composition of the additive of the present embodiment achieves both fixing performance and developability without lowering both dispersibility. be able to.
[0088]
Here, if the carbon number of the long-chain alkyl of the wax is smaller than 5, the releasing effect is weakened, and the separability and the non-offset property at high temperatures are reduced. If the carbon number of the long-chain alkyl is larger than 100, the dispersibility in the binder resin is deteriorated. If the acid value is smaller than 5 mgKOH / g, the charge amount of the toner during long-term use is reduced. If the acid value is more than 80 mgKOH / g, the moisture resistance will decrease and the fog under high humidity will increase. If the melting point is lower than 80 ° C., the storability of the toner decreases. If the melting point is higher than 120 ° C., the releasing effect is weakened, and the non-offset temperature width is narrowed. If the penetration at 25 ° C. is more than 4, the toughness is reduced, and filming occurs on the photoreceptor and the intermediate transfer member during long-term use.
[0089]
Weight average molecular weight is less than 1000, Z average molecular weight is less than 1500, weight average molecular weight / number average molecular weight is less than 1.1, Z average molecular weight / number average molecular weight is less than 1.5, maximum molecular weight peak Is 1 × 10 ³ If it is located within a smaller range, the storage stability of the toner is reduced, filming occurs on the photoreceptor and the intermediate transfer member, vertical stripes on the developing roller, defective scraping on the cleaning roller, and the like occur.
[0090]
Weight average molecular weight greater than 6000, Z average molecular weight greater than 9000, weight average molecular weight / number average molecular weight greater than 3.8, Z average molecular weight / number average molecular weight greater than 6.5, 3 × 10 peaks ⁴ If it is located in a range larger than the region, the releasing effect is weakened and the fixing offset property is reduced.
[0091]
More preferably, the weight average molecular weight is 1,000 to 5,000, the Z average molecular weight is 1,700 to 8,000, the ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.1 to 2.8, and the Z average molecular weight is The ratio of number average molecular weight (Z average molecular weight / number average molecular weight) is 1.5 to 4.5, 1 × 10 ³ ~ 1 × 10 ⁴ Preferably has at least one maximum molecular weight peak in the region, more preferably has a weight average molecular weight of 1000 to 2500, a Z average molecular weight of 1900 to 3000, and a ratio of weight average molecular weight to number average molecular weight (weight average molecular weight / number average). Molecular weight) is 1.2 to 1.8, and the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 1.7 to 2.5, 1 × 10 ³ ~ 3 × 10 ³ Has at least one molecular weight maximum peak in the region.
[0092]
As the alcohol, those having a long alkyl chain such as octanol, dodecanol, stearyl alcohol, nonacosanol, and pentadecanol can be used. As the amines, N-methylhexylamine, nonylamine, stearylamine, nonadecylamine and the like can be suitably used. As the fluoroalkyl alcohol, 1-methoxy- (perfluoro-2-methyl-1-propene), hexafluoroacetone, 3-perfluorooctyl-1,2-epoxypropane and the like can be preferably used. As the unsaturated polycarboxylic acid or anhydride thereof, one or more of maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and the like can be used. Of these, maleic acid and maleic anhydride are more preferred. As the synthetic hydrocarbon wax, polyethylene, polypropylene, Fischer-Tropsch wax, α-olefin and the like can be suitably used.
[0093]
The unsaturated polycarboxylic acid or its anhydride is polymerized using an alcohol or an amine, and then this is added to a synthetic hydrocarbon wax in the presence of diculumi peroxide or tertiary butyl peroxyisopropyl monocarbonate. Can be obtained.
[0094]
The addition amount is preferably 1 to 20 parts by weight based on 100 parts by weight of the binder resin. If it is less than 1, the releasing effect is hardly obtained. If it is more than 20, not only the fluidity of the toner decreases, but even if it is added more, the effect is not improved due to saturation.
[0095]
Higher fatty acids such as polyolefin waxes such as polyethylene and polypropylene, stearic acid, palmitic acid, lauric acid, aluminum stearate, barium stearate, zinc stearate, zinc palmitate, and the like, or metal products thereof can be preferably used.
[0096]
Further, particles having a dispersion average particle diameter of 0.1 to 1.5 μm and a particle diameter distribution of less than 0.1 μm in the binder resin of the wax are 35% by number or less, and particles of 0.1 to 2.0 μm. It is preferable that the number of particles exceeding 65 number% and exceeding 2.0 μm is 5 number% or less. The particle size and the number thereof were determined from a cross-sectional photograph of the toner by TEM.
[0097]
When the dispersion average particle size is smaller than 0.1 μm and the particles having a dispersion average particle size of smaller than 0.1 μm are more than 35% by number, the releasing effect as a releasing agent is small and the fixing ability cannot be exhibited. When the average particle diameter of the dispersion is larger than 1.5 μm and the number of particles exceeding 2.0 μm is more than 5% by number, the dispersibility of the wax in the resin is deteriorated, and the repulsion due to the charge action of the toner is hardly alleviated. Further, fog and toner scattering increase.
[0098]
The binder resin of this embodiment has a molecular weight distribution of 2 × 10 ³ ~ 3 × 10 ⁴ Has at least one molecular weight maximal peak in the region, and 3 × 10 ⁴ Having a molecular weight component of 5% or more based on the entire binder resin, a weight average molecular weight of 10,000 to 300,000, a Z average molecular weight of 20,000 to 500,000, and a ratio of weight average molecular weight to number average molecular weight (weight average (Molecular weight / number average molecular weight) is 3 to 100, the ratio of Z average molecular weight to number average molecular weight (Z average molecular weight / number average molecular weight) is 10 to 2000, and the melting temperature (hereinafter softening) by the 1/2 method using a Koka flow tester. (Point) is preferably from 80 to 150 ° C, the outflow starting temperature is from 80 to 120 ° C, and the glass transition point of the resin is preferably from 45 to 68 ° C.
[0099]
Preferably, the weight average molecular weight is 10,000 to 120,000, the Z average molecular weight is 20,000 to 300,000, the weight average molecular weight / number average molecular weight is 3 to 50, the Z average molecular weight / number average molecular weight is 10 to 1000, and the softening point is 90. It is preferable to use a polyester resin having a temperature of ~ 140 ° C, an outflow starting temperature of 85 to 115 ° C, and a glass transition temperature of 52 to 65 ° C. More preferably, the weight average molecular weight is 10,000 to 40,000, the Z average molecular weight is 20,000 to 100,000, the weight average molecular weight / number average molecular weight is 3 to 20, the Z average molecular weight / number average molecular weight is 10 to 100, and the softening point is It is preferable to use a polyester resin having a temperature of 105 to 135 ° C, an outflow starting temperature of 90 to 120 ° C, and a glass transition temperature of 58 to 65 ° C.
[0100]
As a component existing in the high molecular weight region, preferably 1 × 10 ⁵ It is preferable that the above molecular weight component is contained in an amount of 3% or more based on the whole binder resin. Further, as a component existing in the high molecular weight region, 3 × 10 ⁵ It is preferable that the above molecular weight components are contained in an amount of 0.5% or more based on the whole binder resin.
[0101]
Preferably, as a component existing in the high molecular weight region, 8 × 10 ⁴ ~ 1 × 10 ⁷ Has a molecular weight component of 3% or more based on the whole binder resin, and 1 × 10 ⁷ A configuration not containing the above components is preferable.
[0102]
More preferably, as a component existing in the high molecular weight region, 3 × 10 ⁵ ~ 9 × 10 ⁶ Has a high molecular weight component of 1% or more based on the whole binder resin, and 9 × 10 ⁶ The above components are not contained.
[0103]
More preferably, as a component existing in the high molecular weight region, 7 × 10 ⁵ ~ 6 × 10 ⁶ Has a high molecular weight component of 1% or more based on the whole binder resin, and 6 × 10 ⁶ The above components are not contained.
[0104]
If the amount of the high molecular weight component is too large or too large, the giant molecular weight component remains during kneading, which impairs light transmission. Also, the production efficiency of the resin itself decreases. Further, the developing roller supply roller is unnecessarily scratched to cause vertical streaks in the image. Also, the dispersibility of the wax decreases.
[0105]
The binder resin has a weight average molecular weight of less than 10,000, a Z average molecular weight of less than 20,000, a weight average molecular weight / number average molecular weight of less than 3, a Z average molecular weight / number average molecular weight of less than 10, and a softening point of 80. When the temperature is lower than 80 ° C., the outflow starting temperature is lower than 80 ° C., and the glass transition point is lower than 45 ° C., the dispersibility at the time of kneading is reduced, which causes an increase in fog and a deterioration in durability. Further, kneading stress during kneading is not sufficiently applied, and the molecular weight cannot be maintained at an appropriate value. The dispersibility of the wax and the charge control agent in the resin is deteriorated, and the repulsion due to the charge action of the toner is not easily reduced. Further, fog and toner scattering increase. In addition, the offset resistance and the high-temperature storage stability are deteriorated, and further, cleaning failure in the transfer member and filming on the photosensitive member occur.
[0106]
The binder resin has a weight average molecular weight of more than 300,000, a Z average molecular weight of more than 500,000, a weight average molecular weight / number average molecular weight of more than 100, a Z average molecular weight / number average molecular weight of more than 2000, and a softening point of 150. If the temperature is greater than 120 ° C., the outflow starting temperature is greater than 120 ° C., and the glass transition point is greater than 68 ° C., the load during the processing of the machine becomes excessive, resulting in an extreme decrease in productivity and a decrease in light transmittance in a color image. Or a decrease in fixing strength.
[0107]
Further, the molecular weight distribution of the toner after the melt-kneading and pulverization and classification treatment in GPC is 2 × 10 ³ ~ 3 × 10 ⁴ Has at least one maximum molecular weight peak in the region of 5 × 10 ⁴ ~ 1 × 10 ⁶ Has at least one maximum molecular weight peak or shoulder in the region.
[0108]
The maximum molecular weight peak existing on the low molecular weight side of the toner is preferably 3 × 10 ³ ~ 2 × 10 ⁴ At least one in the region, more preferably 4 × 10 ³ ~ 2 × 10 ⁴ In at least one region.
[0109]
The position of the maximum molecular weight peak or shoulder present on the high molecular weight side of the toner is preferably 6 × 10 ⁴ ~ 7 × 10 ⁵ At least one, more preferably 8 × 10 ⁴ ~ 5 × 10 ⁵ Has at least one maximum molecular weight peak or shoulder in the region.
[0110]
The maximum molecular weight peak position of the molecular weight distribution of the toner existing on the low molecular weight side is 2 × 10 ³ If it becomes smaller, the durability deteriorates and 3 × 10 ⁴ If it is larger, the fixing property is deteriorated, and the light transmittance is reduced.
[0111]
Further, the position of the maximum molecular weight peak or shoulder of the molecular weight distribution of the toner existing on the high molecular weight side is 5 × 10 ⁴ If it is smaller, the offset resistance decreases and the storage stability deteriorates. Developability deteriorates and waste toner recyclability also decreases. 1 × 10 ⁶ If the size is larger, the pulverizability is reduced, and the production efficiency is reduced.
[0112]
Further, as a component existing in the high molecular weight region of the toner, 5 × 10 ⁵ It is preferable that the content of the high molecular weight component is 10 wt% or less based on the whole binder resin. 5 × 10 ⁵ When the amount of components existing in the high molecular weight region increases, light transmittance is significantly impaired. In addition, fog increases due to poor dispersion, scratches occur on the developing roller and the supply roller, and the pulverizability of the toner is deteriorated, thereby lowering the production efficiency.
[0113]
More preferably, 5 × 10 ⁵ The content of the high molecular weight component is 5% or less based on the whole binder resin, and more preferably 1 × 10 ⁶ The content of the above high molecular weight component is 1% or less with respect to the entire binder resin, or the content is not contained.
[0114]
The molecular weight distribution in the GPC chromatogram of the toner was 2 × 10 ³ ~ 3 × 10 ⁴ The height of the molecular weight distribution of the maximum molecular weight peak existing in the region of ⁴ ~ 1 × 10 ⁶ Hb / Ha is 0.15 to 0.9, where Hb is the height of the maximum molecular weight peak or shoulder existing in the region.
[0115]
If Hb / Ha is less than 0.15, the offset resistance deteriorates, the storage stability decreases, and the result is that filming on the developing sleeve and the photoconductor is promoted. If the ratio is larger than 0.9, the developing roller supply roller is damaged, and the pulverizability is deteriorated, thereby lowering the productivity and increasing the cost. More preferably, Hb / Ha is 0.15 to 0.7, and still more preferably, Hb / Ha is 0.2 to 0.6.
[0116]
The molecular weight distribution of the toner by GPC is 2 × 10 ³ ~ 3 × 10 ⁴ At least one molecular weight maximum peak in the region of 5 × 10 ⁴ ~ 1 × 10 ⁶ Having at least one maximum molecular weight peak or shoulder in the region of ⁴ ~ 1 × 10 ⁶ Focusing on a molecular weight curve present in a region having a maximum molecular weight distribution or a molecular weight value larger than the molecular weight value corresponding to the shoulder existing in the region, and setting the maximum peak of the molecular weight distribution or the height of the shoulder as 100% as a reference, the maximum molecular weight peak thereof Alternatively, when the molecular weight corresponding to 90% of the height of the shoulder is M90 and the molecular weight corresponding to the maximum molecular weight peak or 10% of the height of the shoulder is M10, M10 / M90 is 0.1. It can be realized by setting it to 5 to 8. Furthermore, by setting (M10−M90) / M90 to 0.1 to 7, high light-transmitting properties can be ensured and oil-less fixing that can prevent offset without the need for a fixing oil can be realized.
[0117]
Defining the value of M10 / M90, and further, the value of (M10−M90) / M90 (the slope of the molecular weight distribution curve) can quantify the state of molecular cleavage of the ultrahigh molecular weight component. If it is within the stated range (indicating that the slope of the molecular weight distribution curve is steep), the ultra-high molecular weight component that inhibits light transmission is lost by cutting during kneading, resulting in high light transmission. Will have. Furthermore, the high molecular weight component that forms peaks or shoulders appearing on the polymer side contributes to the offset resistance, and it is possible to prevent the occurrence of offset of the color toner without using oil.
[0118]
Furthermore, when this ultra-high molecular weight component is molecularly cut, it is possible to uniformly disperse the wax and the charge control agent in the binder resin, and the charge amount is made uniform, and a sharp resolution is obtained. Even if used for a long period of time, the durability is not deteriorated. In addition, the cleaning property of the transfer body is improved, and no vertical streaks are generated on the developing roller, and the image is prevented from being disturbed during transfer, and a dropout can be prevented, so that highly efficient transfer property can be obtained.
[0119]
If the value of M10 / M90 is greater than 8, or (M10-M90) / M90 is greater than 7, the ultrahigh molecular weight component still remains, impairing light transmission. If the value of M10 / M90 is smaller than 0.5, or if (M10-M90) / M90 is smaller than 0.1, the mechanical load during kneading becomes excessive, and the productivity decreases. The durability of the toner decreases. More preferably, the value of M10 / M90 is 0.5 to 6, and (M10-M90) / M90 is 0.1 to 4.5. More preferably, the value of M10 / M90 is 0.5 to 4.5, and (M10-M90) / M90 is 0.1 to 3.5.
[0120]
This makes it possible to use digital image quality, high color reproducibility and color, and to be able to use the developing roller and supply roller stably for a long period of time in contact-type one-component development. It is possible to achieve both light transmittance and anti-offset properties, and to realize a cleaner process, a short distance between transfers, prevention of dropout in a transfer step in a short tandem transfer process, and high transferability.
[0121]
By kneading the above-mentioned binder resin with a high shearing force in the melt-kneading treatment, it is possible to exhibit unprecedented characteristics. By fixing without using oil, it is possible to achieve both the high translucency and the offset resistance of the color toner. In other words, the binder resin to which the ultra-high molecular weight component has been imparted has a high shear force to lower the ultra-high molecular weight component to a low molecular weight, thereby exhibiting high translucency. Offset properties are also satisfactory. In addition, since it has an ultra-high molecular weight component, a high shear force is applied during kneading, so that the wax can be more uniformly dispersed, the translucency is improved, non-offset properties, high image quality, high color reproducibility, Good transferability is obtained.
[0122]
After the melt-kneading process, the toner has a weight average molecular weight of 8,000 to 180,000, a Z average molecular weight of 18,000 to 450,000, a ratio of weight average molecular weight to number average molecular weight (weight average molecular weight / number average molecular weight) of 3 to 80, and Z average. The ratio of the molecular weight to the number average molecular weight (Z average molecular weight / number average molecular weight) is 10 to 1000.
[0123]
By kneading the toner in this proper range with a high shearing force, it is possible to achieve both high translucency and offset resistance of the color toner by fixing without using oil.
[0124]
Preferably, the weight average molecular weight is 8,000 to 100,000, the Z average molecular weight is 18,000 to 300,000, the weight average molecular weight / number average molecular weight is 3 to 60, and the Z average molecular weight / number average molecular weight is 10 to 500.
[0125]
More preferably, the weight average molecular weight is 10,000 to 40,000, the Z average molecular weight is 20,000 to 80,000, the weight average molecular weight / number average molecular weight is 3 to 30, and the Z average molecular weight / number average molecular weight is 10 to 50. preferable.
[0126]
When the weight average molecular weight is smaller than 8000, the Z average molecular weight is smaller than 18,000, the weight average molecular weight / number average molecular weight is smaller than 3, and the Z average molecular weight / number average molecular weight is smaller than 10, kneading stress is not sufficiently applied, The molecular weight cannot be maintained at an appropriate value. The dispersibility of the wax is reduced, and the offset resistance and the high-temperature preservability are deteriorated. Further, poor cleaning at the intermediate transfer member and filming on the photoreceptor occur.
[0127]
When the weight-average molecular weight is greater than 180,000, the Z-average molecular weight is greater than 450,000, the weight-average molecular weight / number-average molecular weight is greater than 80, and the Z-average molecular weight / number-average molecular weight is greater than 1000, the shear force pressure acts too much. Conversely, the internal additives such as the charge control agent coagulate with each other, leading to a decrease in dispersibility, resulting in an increase in fog, a decrease in image density, and a poor transfer during the cleanerless process. Further, the fixing strength is reduced, and the light transmittance and glossiness are reduced.
[0128]
The binder resin has a THF-insoluble component of 5% by weight or less, and preferably has no THF-insoluble component. If the amount of the THF-insoluble component is more than 5% by weight, the light transmittance of the color image is deteriorated, and the image quality is deteriorated.
[0129]
As the binder resin suitably used in the present embodiment, a polyester resin obtained by polycondensation of an alcohol component and a carboxylic acid component such as carboxylic acid, carboxylic acid ester and carboxylic anhydride is preferably used.
[0130]
Examples of the divalent carboxylic acid or lower alkyl ester include malonic acid, succinic acid, glutaric acid, adipic acid, aliphatic dibasic acids such as hexahydrophthalic anhydride, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid And aliphatic dibasic acids such as phthalic anhydride, phthalic acid, terephthalic acid and isophthalic acid, and their methyl esters and ethyl esters. Among these, aromatic dibasic acids such as succinic acid, phthalic acid, terephthalic acid, and isophthalic acid, and lower alkyl esters thereof are preferred. It is preferable to use succinic acid and terephthalic acid or a combination of phthalic acid and terephthalic acid.
[0131]
The trivalent or higher carboxylic acid component includes 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, , 2,4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexatricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) Examples thereof include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empoll trimer acid, acid anhydrides thereof, and alkyl (C1 to C12) esters.
[0132]
Examples of the dihydric alcohol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, Examples thereof include diols such as dipropylene glycol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct, triols such as glycerin, trimethylolpropane, and trimethylolethane, and mixtures thereof. Of these, bisphenol A shown in (Chemical Formula 1), derivatives thereof, alkylene oxide adducts thereof, neopentyl glycol and totimethylolpropane are particularly preferred.
[0133]
Embedded image

[0134]
Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, , 2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and the like. Can be
[0135]
For the polymerization, known polycondensation, solution polycondensation and the like can be used. Thereby, a good toner can be obtained without impairing the PVC mat resistance and the color of the color material of the color toner.
[0136]
Generally, the ratio of the number of hydroxyl groups to the number of carboxyl groups (OH / COOH) is generally 0.8 to 1.4.
[0137]
The molecular weights of resins, waxes and toners are values measured by gel permeation chromatography (GPC) using several types of monodisperse polystyrene as standard samples.
[0138]
The apparatus was HPLC 8120 series manufactured by Tosoh Corporation, the column was TSKgelsuperHM-HH4000 / H3000 / H2000 (7.8 mm diameter, 150 mm × 3), eluent THF (tetrahydrofuran), flow rate 0.6 ml / min, sample concentration 0.1%, Injection volume: 20 μL, detector RI, measurement temperature: 40 ° C., pre-measurement treatment: After dissolving the sample in THF, filter with a 0.45 μm filter to remove resin components such as silica, and measure the resin component. The measurement condition is a condition in which the molecular weight distribution of the target sample is included in a range in which the logarithm of the molecular weight and the count number are linear in a calibration curve obtained from several types of monodisperse polystyrene standard samples.
[0139]
The softening point of the binder resin was 1 cm using a flow tester (CFT500) manufactured by Shimadzu Corporation. ³ While heating the sample at a heating rate of 6 ° C./min, about 9.8 × 10 ⁵ N / m ² The plunger is extruded from a die having a diameter of 1 mm and a length of 1 mm, and the temperature at which the piston stroke starts to rise is determined as the outflow start temperature (Tfb ), The half of the difference between the minimum value of the curve and the end point of the outflow is determined, and the temperature at the point obtained by adding this to the minimum value of the curve is the melting temperature (softening point Tm) in the half method.
[0140]
Using a differential scanning calorimeter, the glass transition point of the resin was raised to 100 ° C., left at that temperature for 3 minutes, and then cooled to room temperature at a temperature lowering rate of 10 K / min. The temperature at the intersection of the extension of the baseline below the glass transition point and the tangent showing the maximum slope from the rising portion of the peak to the top of the peak when measuring the thermal history by raising the temperature.
[0141]
For the melting point of the endothermic peak by DSC, a differential calorimeter DSC-50 manufactured by Shimadzu Corporation was used. The temperature was raised to 200 ° C. at 5 K / min, rapidly cooled to 10 ° C. for 5 minutes, left standing for 15 minutes, then raised at 5 K / min, and determined from the endothermic (melting) peak. The amount of the sample to be charged into the cell was 10 mg ± 2 mg.
[0142]
As the binder resin suitably used in the present embodiment, a homopolymer or a copolymer of various vinyl monomers can also be suitably used. For example, styrene, O-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn butyl styrene, p-tert-butyl styrene, pn-hexyl Examples include styrene and derivatives thereof such as styrene, pn-octylstyrene, pn-hexylstyrene, and P-chlorostyrene, with styrene being particularly preferred.
[0143]
Examples of the acrylic monomer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate, and methacryl. 2-ethylhexyl acid, ethyl β-hydroxyacrylate, propyl γ-hydroxyacrylate, butyl α-hydroxyacrylate, ethyl β-hydroxymethacrylate, propyl γ-aminoacrylate, propyl γ-N, N-diethylaminoacrylate And ethylene glycol dimethacrylate and tetraethylene glycol dimethacrylate. Styrene-acrylic copolymers suitable for the purpose of the present invention are styrene / butyl acrylate copolymers, especially those containing 75 to 85% by weight of styrene and 15 to 25% by weight of butyl acrylate. used.
[0144]
As a method for producing the polymer, known polymerization methods such as bulk polymerization, bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be used. A method of performing bulk polymerization to a polymerization rate of 30 to 90% by weight, adding a solvent and a polymerization initiator, and continuing the reaction by solution polymerization is also preferable.
[0145]
Embodiment 3: Charge control agent
In the present embodiment, a charge control agent is added for the purpose of controlling the charge of the toner and for enhancing the oilless fixing. As a preferable material, an acrylic sulfonic acid polymer such as a vinyl copolymer of a styrene monomer and an acrylic acid monomer having a sulfonic acid group as a polar group is preferable. In particular, a copolymer with acrylamido-2-methylpropanesulfonic acid can exhibit preferable characteristics.
[0146]
As a preferable material, a metal salt of a salicylic acid derivative represented by the following formula (2) is used.
[0147]
Embedded image

[0148]
As a preferable material, a metal salt of a benzylic acid derivative represented by the following chemical formula (3) is used.
[0149]
Embedded image

[0150]
With this configuration, it is possible to secure a wide non-offset temperature range in oilless fixing, and to prevent image disturbance due to a charging action during fixing. This is probably due to the effect of the charge polarity of the metal salt and the functional group having the acid value of the wax. Also, it is possible to prevent a decrease in the charge amount during continuous use. Blade fusing in development can be suppressed.
[0151]
The addition amount is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the binder resin. It is more preferably 1 to 4 parts by weight, and still more preferably 3 to 4 parts by weight. If the amount is less than 0.5 parts by weight, the charging effect is lost. If the amount is more than 5 parts by weight, color turbidity in a color image becomes conspicuous.
[0152]
Examples of the pigment used in the present embodiment include carbon black, iron black, graphite, nigrosine, metal complexes of azo dyes, C.I. I. Pigment Yellow 1,3,74,97,98 and the like. I. Acetoacetate arylamide disazo yellow pigments such as CI Pigment Yellow 12, 13, 14, 17; I. Solvent Yellow 19, 77, 79, C.I. I. Disperse Yellow 164, C.I. I. Red pigments such as CI Pigment Red 48, 49: 1, 53: 1, 57, 57: 1, 81, 122, 5; I. Red dyes such as Solvent Red 49, 52, 58, 8; I. One or more blue dyes of phthalocyanine and its derivatives such as Pigment Blue 15: 3 are blended. The addition amount is preferably 3 to 8 parts by weight based on 100 parts by weight of the binder resin.
[0153]
In this embodiment, as an external additive, fine powders of metal oxides such as silica, alumina, titanium oxide, zirconia, magnesia, ferrite, and magnetite; titanates such as barium titanate, calcium titanate, and strontium titanate; Zirconates such as barium, calcium zirconate and strontium zirconate, or mixtures thereof are used. The external additive is subjected to a hydrophobic treatment as required.
[0154]
As the silicone oil-based material to be treated with silica, those shown in (Formula 4) are preferable.
[0155]
Embedded image

[0156]
For example, dimethyl silicone oil, methyl hydrogen silicone oil, methyl phenyl silicone oil, cyclic dimethyl silicone oil, epoxy modified silicone oil, carboxyl modified silicone oil, carbinol modified silicone oil, methacryl modified silicone oil, mercapto modified silicone oil, polyether modified Silica treated with at least one of silicone oil, methylstyryl-modified silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, amino-modified silicone oil, and chlorophenyl-modified silicone oil is preferably used. For example, SH200, SH510, SF230, SH203, BY16-823, BY16-855B, etc., manufactured by Toray Dow Corning Silicone Co., Ltd. may be mentioned. For the treatment, a method of mixing an inorganic fine powder and a material such as silicone oil with a mixer such as a Henschel mixer, a method of spraying a silicone oil-based material onto silica, or a method of dissolving or dispersing a silicone oil-based material in a solvent After that, there is a method of mixing with the fine silica powder and then removing the solvent to prepare. Preferably, 0.1 to 10 parts by weight of a silicone oil-based material is blended with respect to 100 parts by weight of the inorganic fine powder.
[0157]
As the silane coupling agent, dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzylmethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, There are vinyltriacetoxysilane, divinylchlorosilane, dimethylvinylchlorosilane and the like. The silane coupling agent treatment is a dry process in which a vaporized silane coupling agent is reacted with a cloud of fine powder by stirring or the like, or a wet process in which a silane coupling agent in which fine powder is dispersed in a solvent is dropped. Processed by the method.
[0158]
It is also preferable to treat the silicone oil-based material after the silane coupling treatment.
[0159]
The inorganic fine powder having a positive electrode chargeability is treated with aminosilane, an amino-modified silicone oil shown in Chemical formula 5, or an epoxy-modified silicone oil.
[0160]
Embedded image

[0161]
In order to further enhance the hydrophobic treatment, it is also preferable to use a combination of treatment with hexamethyldisilazane, dimethyldichlorosilane, or another silicone oil. For example, it is preferable to treat with at least one of dimethyl silicone oil, methylphenyl silicone oil, and alkyl-modified silicone oil.
[0162]
Further, use of inorganic fine powder treated with a fatty acid ester, a fatty acid amide, or a fatty acid metal salt is also preferable. Silica or titanium oxide fine powder having one or two or more kinds of surface treated is more preferable.
[0163]
Fatty acids and fatty acid metal salts for surface-treating inorganic fine powders include caprylic acid, capric acid, undecylic acid, lauric acid, mystyric acid, parimitic acid, stearic acid, behenic acid, montanic acid, lacceric acid, oleic acid, erucic acid Sorbic acid, linoleic acid and the like. Among them, fatty acids having 15 to 20 carbon atoms are preferable.
[0164]
Examples of the metal constituting the fatty acid metal salt include aluminum, zinc, calcium, magnesium, lithium, sodium, lead and barium, and among them, aluminum, zinc and sodium are preferred. Particularly preferably, aluminum distearate (Al (OH) (C ₁₇ H ₃₅ COO) ₂ ) Or aluminum monostearate (Al (OH) ₂ (C ₁₇ H ₃₅ COO)), etc., and aluminum difatty acids and aluminum monofatty acids are preferred. Having an OH group can prevent overcharging and suppress transfer failure. Further, it is considered that the processability with an inorganic fine powder such as silica during the treatment is improved.
[0165]
The surface treatment is performed by dissolving the above-described fatty acid in an aromatic solvent, and wet-mixing or spraying it with a fine powder of silica, titanium oxide, alumina, or the like, and agitating to adhere or react the fatty acid on the surface of the fine powder. , Surface treatment, followed by drying and solvent removal. The treatment amount at this time is preferably 0.1 to 25 parts by weight based on 100 parts by weight of the inorganic fine powder base. If it is less than 0.1, the function of the treating agent will not be sufficiently exhibited. If it exceeds 25, the amount of floating fatty acids increases, which adversely affects developability and durability.
[0166]
In a more preferred embodiment, the surface of the inorganic fine powder to be treated is preferably treated with a coupling agent and / or silicone oil, and then treated with a fatty acid and / or a fatty acid metal salt. This is because uniform treatment can be performed as compared with the case where a fatty acid of hydrophilic silica is simply treated, so that the toner can be highly charged and fluidity when added to the toner is improved. In addition, the above-mentioned effects can be obtained even if the fatty acid and / or the fatty acid metal salt is treated together with the coupling agent and / or the silicone oil.
[0167]
In addition, by specifying the composition of the external additive formulation for the toner base having a particle size distribution of fine particles described later, the handleability of the toner particles can be improved, and high image quality can be obtained in development and transfer caused by the fine particles. And improvement of transferability can be achieved at the same time. In development, the latent image can be reproduced more faithfully. Then, at the time of transfer, the fine toner particles can be transferred without deteriorating the transfer rate. In addition, retransfer can be prevented even in tandem transfer, and the occurrence of voids can be suppressed. Furthermore, high image density can be obtained even if the development amount is reduced. It is considered that the particles are dense because the toner is miniaturized.
[0168]
It is preferable that an inorganic fine powder having an average particle diameter of 6 nm to 120 nm is externally added to 2.5 to 5.3 parts by weight based on 100 parts by weight of the toner base particles. If the average particle size is smaller than 6 nm, silica floating and filming on the photoreceptor are likely to occur. The occurrence of reverse transfer during transfer cannot be suppressed. If it is larger than 120 nm, the fluidity of the toner deteriorates. If the amount is less than 2.5 parts by weight, the fluidity of the toner deteriorates. The occurrence of reverse transfer during transfer cannot be suppressed. If the amount is more than 5.3 parts by weight, silica floating and filming on the photoreceptor are likely to occur.
[0169]
Furthermore, 1.0 to 2.5 parts by weight of the inorganic fine powder having an average particle diameter of 6 nm to 20 nm with respect to 100 parts by weight of the toner base particles, and 100 parts by weight of the inorganic fine powder having an average particle diameter of 30 nm to 120 nm are used. It is preferable that at least 1.5 to 2.8 parts by weight of the composition be externally added. With the use of the silica whose functions are separated by this configuration, it is possible to obtain a better margin for handling in development, reverse transfer during transfer, dropout, and scattering. By deviating from the range, the margin width is narrowed, and improvement in accuracy on the machine side is required.
[0170]
Further, an inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% is 1.0 to 2.5 parts by weight based on 100 parts by weight of the toner base particles. It is preferable that at least 1.5 to 2.8 parts by weight of an inorganic fine powder having a loss on ignition of 0.1 to 23 wt% at 30 nm to 120 nm is added to at least 1.5 to 2.8 parts by weight of the toner base particles.
[0171]
By specifying the loss on ignition of silica, it is possible to obtain a better margin for handling in development, reverse transfer during transfer, dropout, and scattering. By deviating from the range, the margin width is narrowed, and improvement in accuracy on the machine side is required. In particular, the releasing effect at the time of transfer can be stabilized, and the transfer margin against reverse transfer and hollowing out can be stabilized.
[0172]
When the ignition loss at an average particle diameter of 6 nm to 20 nm is less than 0.5 wt%, the transfer margin for reverse transfer and hollowing out becomes narrow. If the content is more than 25 wt%, the surface treatment becomes uneven, and the charging varies. Preferably, the ignition loss is 1.5 to 20 wt%, more preferably 5 to 19 wt%.
[0173]
When the ignition loss at an average particle diameter of 30 nm to 120 nm is less than 0.1 wt%, the transfer margin for reverse transfer and hollowing out becomes narrow. If the content is more than 23 wt%, the surface treatment becomes uneven, and uneven charging occurs. Preferably, the ignition loss is 1.5 to 18 wt%, more preferably 5 to 16 wt%.
[0174]
Further, 1.8 to 4 parts by weight of the negatively chargeable inorganic fine powder having an average particle diameter of 6 to 120 nm and a loss on ignition of 0.5 to 25 wt% with respect to 100 parts by weight of the toner base particles, It is preferable that at least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having a thickness of 120 nm and a loss on ignition of 0.5 to 25 wt% is externally added to 100 parts by weight of the toner base particles.
[0175]
The effect of adding the positively chargeable inorganic fine powder is to prevent the toner from being overcharged due to life or the like, and to further extend the life of the developer. Further, an effect of suppressing scattering at the time of transfer due to overcharging can be obtained. If the amount is less than 0.5 parts by weight, it is difficult to obtain the effect. If the amount is more than 1.5 parts by weight, fogging in development increases. The ignition loss is preferably 1.5 to 20 wt%, more preferably 5 to 19 wt%.
[0176]
Further, 0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles, Is from 1.2 to 2.0 parts by weight based on 100 parts by weight of the toner base particles, and the average particle diameter is from 6 to 20 nm. It is preferable that at least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having a loss on ignition of 0.5 to 25 wt% is externally added to 100 parts by weight of the toner base particles.
[0177]
By using a negatively-chargeable inorganic fine powder having a function separated by this constitution, for example, silica, it is possible to obtain more margin for handling in development, reverse transfer at the time of transfer, dropout, and scattering. By deviating from the range, the margin width is narrowed, and improvement in accuracy on the machine side is required. Further, by adding a positively chargeable inorganic fine powder having a thickness of 6 nm to 20 nm, it is possible to suppress the toner from being overcharged due to life or the like, and to further extend the life of the developer. Further, an effect of suppressing scattering at the time of transfer due to overcharging can be obtained. Stability in development is stable. It is effective in stabilizing the life in life. The ignition loss of the inorganic fine powder having a thickness of 6 nm to 20 nm is 1.5 to 20 wt%, more preferably 5 to 19 wt%. The ignition loss of the inorganic fine powder having a thickness of 30 nm to 120 nm is preferably 1.5 to 18 wt%, more preferably 5 to 16 wt%.
[0178]
Further, 0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles, Is from 1.2 to 2.0 parts by weight per 100 parts by weight of the toner base particles, and the average particle diameter is from 30 to 120 nm. It is preferred that the positively chargeable inorganic fine powder having a loss on ignition of 0.1 to 23% by weight is externally added to 0.5 to 1.5 parts by weight based on 100 parts by weight of the toner base particles. . The use of a positively chargeable inorganic fine powder having a thickness of 30 nm to 120 nm provides an effect of stabilizing the life of the product and preventing the occurrence of a dropout in the transfer and the prevention of the reverse transfer. The ignition loss of the inorganic fine powder having a thickness of 6 nm to 20 nm is 1.5 to 20 wt%, more preferably 5 to 19 wt%. The ignition loss of the inorganic fine powder having a thickness of 30 nm to 120 nm is preferably 1.5 to 18 wt%, more preferably 5 to 16 wt%.
[0179]
The loss on drying (%) is determined by taking about 1 g of a sample in a container which has been dried, cooled and precisely weighed in advance, and precisely weighed. Dry for 2 hours in a hot air dryer (105 ° C ± 1 ° C). After cooling in a desiccator for 30 minutes, the weight is precisely weighed and calculated by the following equation.
[0180]
Loss on drying (%) = Loss on drying (g) / Sample weight (g) x 100
For the ignition loss, about 1 g of a sample is placed in a magnetic crucible which has been dried, cooled, and precisely weighed in advance, and precisely weighed. Ignite for 2 hours in an electric furnace set at 500 ° C. After allowing to cool in a desiccator for one hour, the weight is precisely weighed and calculated by the following equation.
[0181]
Loss on ignition (%) = Loss on ignition (g) / Sample amount (g) x 100
For the determination of the degree of hydrophobicity, 0.2 g of the product to be tested is weighed in 50 ml of distilled water charged in a 250 ml beaker. At the tip, methanol is dropped from a burette immersed in the liquid until the total amount of the inorganic fine powder is wet. At this time, the mixture is constantly stirred slowly with a magnetic stirrer. The degree of hydrophobicity is calculated from the amount of methanol a (ml) essential for complete wetting by the following equation.
[0182]
Degree of hydrophobicity = (a / (50 + a)) × 100 (%)
Further, the treated inorganic fine powder preferably has a water adsorption amount of 1 wt% or less. It is preferably at most 0.5 wt%, more preferably at most 0.1 wt%, even more preferably at most 0.05 wt%. If the content is more than 1 wt%, the chargeability is reduced and filming on the photoconductor at the time of durability is caused. The water adsorption amount was measured with a continuous vapor adsorption device (BELSORP18: Bell Japan Co., Ltd.).
[0183]
In this embodiment, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax containing the binder and the colorant and the wax is 3.5 to 5.5 μm, and is 5.04 μm or less in the number distribution. When the content is 60% by number or more, the content of 3.17 μm or less in the number distribution is 5 to 35% by number, and the toner particles having a particle size of 6.35 to 10.1 μm are 35% by volume or less. The particle size distribution is included.
[0184]
In a further preferred embodiment, the volume average particle diameter of the toner containing at least the binder resin, the colorant and the wax is 3.5 to 5.5 μm, and the content of 5.04 μm or less in the number distribution is 60% by number or more. 5% to 35% by number of 3.17 μm or less in the number distribution, and 30% by volume or less of toner particles having a particle size of 6.35 to 10.1 μm in the number distribution, and 8 μm in the number distribution. The particle size distribution is such that the content is 1% by volume or less. Means for realizing this particle size distribution will be described later.
[0185]
It is possible to achieve high-resolution image quality, prevent reverse transfer in tandem transfer, prevent omission, and achieve compatibility with oilless fixing.
[0186]
If the volume average particle size of the image is larger than 5.5 μm, it is impossible to achieve both image quality and transfer. If the volume average particle diameter is smaller than 3.5 μm, it becomes difficult to handle the toner particles in development. If the content of 5.04 μm or less in the number distribution is less than 60% by number, it is not possible to achieve both image quality and transfer. If the content of 3.17 μm or less in the number distribution is less than 5% by number, both image quality and transfer cannot be achieved. If the content is more than 35% by number, the hand rigging of the toner particles in development becomes difficult. If toner particles having a particle diameter of 6.35 to 10.1 μm are contained in an amount of more than 35% by volume, it is impossible to achieve both image quality and transfer.
[0187]
Further, when toner particles having a particle diameter of 6.35 to 10.1 μm are contained in an amount of more than 30% by volume, and a content of 8 μm or more in the number distribution is more than 1% by volume, the image quality and the transfer of the image are improved. I can not achieve both.
[0188]
Further, the specific surface area ratio SSt (SSt = (St / the ratio of the pulverized toner) to the specific surface area value St (St = 6 / (true specific gravity * volume average particle diameter)) equivalent to a true sphere converted from the volume average particle diameter. Surface area value) can be 0.4 to 0.9, preferably 0.5 to 0.85, and more preferably 0.55 to 0.8. If the ratio is smaller than 0.4, the shape becomes too irregular, or the amount of excessively pulverized fine powder is large.
[0189]
The variation coefficient of the volume particle size distribution of the toner is preferably 15 to 32%, and the variation coefficient of the number particle size distribution is preferably 15 to 35%. More preferably, the coefficient of variation of the volume particle size distribution is 15 to 30%, the coefficient of variation of the number particle size distribution is 15 to 30%, even more preferably, the coefficient of variation of the volume particle size distribution is 15 to 25%, The coefficient of variation of the distribution is 15 to 25%.
[0190]
The variation coefficient is obtained by dividing the standard deviation of the toner particle diameter by the average particle diameter. It is based on the particle diameter measured using a Coulter counter (Coulter). The standard deviation is represented by the square root of a value obtained by dividing the square of the difference from the average value of each measured value when measuring n particle systems by (n-1).
[0191]
In other words, the coefficient of variation is a measure of the degree of spread of the particle size distribution. If the coefficient of variation of the volume particle size distribution is less than 15%, or the coefficient of variation of the number particle size distribution is less than 15%, it is difficult to produce, This will increase costs. If the coefficient of variation of the volume particle size distribution is larger than 32% or the coefficient of variation of the number particle size distribution is larger than 35%, the cohesiveness of the toner becomes stronger when the particle size distribution becomes broad, and filming and transfer to the photoreceptor are performed. It is difficult to recover the residual toner in the defective and cleanerless process.
[0192]
Fine powder in the toner affects the fluidity, image quality, storage stability of the toner, filming on the photosensitive member, the developing roller, and the transfer member, aging characteristics, and transferability, particularly, multi-layer transferability in a tandem system. Furthermore, it affects non-offset properties, glossiness, and light transmission in oilless fixing. In a toner containing a release agent such as wax for realizing oil-less fixing, the amount of fine powder affects compatibility with tandem transferability.
[0193]
If the amount of the fine powder is excessively large, the wax that cannot be dispersed becomes more exposed on the toner surface, and filming occurs on the photosensitive member, the developing roller, and the transfer member. Furthermore, the fine powder tends to be easily offset because of high adhesion to the heat roller. Further, in the tandem method, the aggregation of the toner is likely to be strong, and the transfer failure of the second color is likely to occur during the multi-layer transfer. On the other hand, when the amount of fine powder is small, the image quality is reduced.
[0194]
The particle size distribution is measured using a Coulter Counter TA-II (Coulter Counter Co., Ltd.) and connected to an interface (manufactured by Nikkaki) for outputting the number distribution and volume distribution and a personal computer. The electrolyte was added with a surfactant (sodium lauryl sulfate) to a concentration of 1%, and about 2 mg of the toner to be measured was added to about 50 ml, and the electrolyte in which the sample was suspended was subjected to dispersion treatment with an ultrasonic disperser for about 3 minutes. And an aperture of 70 μm was used with a Coulter Counter TA-II. In the case of a 70 μm aperture system, the particle size distribution measurement range is 1.26 μm to 50.8 μm. However, the area smaller than 2.0 μm is not practical because measurement accuracy and measurement reproducibility are low due to external noise and the like. Therefore, the measurement area was set to 2.0 μm to 50.8 μm.
[0195]
The degree of compression is calculated from the static bulk density and the dynamic bulk density, and is one of the indexes of toner fluidity. The fluidity of the toner is affected by the particle size distribution of the toner, the shape of the toner particles, the type and amount of external additives and wax. When the particle size distribution of the toner is narrow and the amount of fine powder is small, when the surface of the toner has little irregularity and the shape is nearly spherical, when the amount of the external additive added is large, and when the particle size of the external additive is small, the degree of compression is small. The fluidity of the toner becomes higher. The degree of compression is preferably from 5 to 40%. More preferably, it is 10 to 30%. It is possible to achieve both oilless fixing and tandem type multi-layer transfer. If it is less than 5%, the fixing property is reduced, and particularly the light transmittance tends to be deteriorated. The toner scatters easily from the developing roller. The transferability of more than 40% is reduced, resulting in tandem dropout and poor transfer.
[0196]
By kneading with a high shearing force, the added wax can be finely dispersed. The kneading conditions of the temperature setting and the temperature gradient of the roll, the number of rotations and the load current, and the softening point and the glass transition point of the binder resin are processed under the optimum conditions, whereby the high dispersion treatment can be performed. High shear force refers to the kneading force acting on the toner material such as binder resin by rotating the rolls facing each other in a narrow gap at high speed, and has a difference in rotational speed from the force generated when sandwiched in a narrow gap. Refers to the shear force received from the rotating roll. It has a kneading force that cannot be exhibited by a conventional twin-screw extruder. This makes it possible to reduce the high molecular weight component of the binder resin.
[0197]
Specifically, it has two opposing rolls that rotate in different directions and can be heated or cooled, and a temperature difference between the roll temperature of one roll (RL1) and the roll temperature of the other roll (RL2). This can be realized by providing and rotating the roll (RL1) and the roll (RL2) at different peripheral speeds and kneading between the two rolls. Further, one roll (RL1) is configured to have a temperature difference between the first half and the second half.
[0198]
By setting the rotation speed ratio of the two rolls within the range of 1.1 to 2.5 times, an appropriate shear force is generated at the time of kneading, thereby cutting the molecular weight of the binder resin and dispersing the internal additives such as the colorant. And fixability and developability are improved. The configuration is such that the rotation ratio of the roll on the side on which the toner is heated to melt and wind the toner is increased. When the ratio is 1.1 times or less, an appropriate shearing force is not generated, dispersibility is not improved, and light transmittance is deteriorated. Conversely, when the ratio is 2.5 times or more, the productivity is sharply reduced, the dispersibility is not improved, and the developability is deteriorated.
[0199]
In addition, by kneading under the condition that the ratio of the load current value applied to the two rolls at this time is in the range of 1.25 to 10, an appropriate shear force is applied, and the dispersibility of the internal additive is improved. . If it is smaller than this range, the dispersibility is not improved, and the light transmittance is deteriorated. Also, productivity is reduced. Conversely, if it is larger than this range, the load applied to the roller becomes too large, and the ultra-high molecular weight component becomes too low in molecular weight, so that the non-offset property is reduced and offset occurs.
[0200]
FIG. 1 is a schematic perspective view of the toner melt-kneading process, FIG. 2 is a plan view as viewed from above, FIG. 3 is a side view as viewed from the left side, and FIG. Reference numeral 601 denotes a toner raw material supply device, 602 denotes a roll (RL1), 603 denotes a roll (RL2), and 604 denotes a toner melt film wound around the roll (RL1). In FIG. 4, the roll 602 rotates clockwise, and the roll 603 rotates counterclockwise. 602-1 is the first half of the roll (RL1) (upstream in the direction of transport of the raw material), 602-2 is the second half of the roll (RL1) (downstream of the direction of transport of the raw material), and 603-1 is the roll (RL2) 603-2 for heating the first half of the roll (RL2) (downstream in the material transport direction), and 605 for heating the first half 602-1 of the roll (RL1). 606 is an outlet for the heat medium that has heated the first half 602-1 of the roll (RL1), and 607 is a medium flow for heating or cooling the second half 602-2 of the roll (RL1). An inlet 608 is an outlet for the medium that heats or cools the rear half 602-2 of the roll (RL1), 618 is an inlet for a heat medium for heating or cooling the front half 603-1 of the roll (RL2), 619 Is the first half of the roll (RL2) 03-1 is an outlet of a heat medium that has heated or cooled 03-1, 609 is an inlet of a medium for heating or cooling the rear half 603-2 of the roll (RL2), and 610 is a rear half 603-2 of the roll (RL2). 611 is a spiral groove on the surface of the roll and has a depth of about 2 to 10 mm, and 612 is a toner reservoir formed between the rolls. The spiral groove 611 is preferable for smoothly transporting the material from the right end of the raw material input section to the left end of the discharge section at the time of kneading the toner. 603-1 is for applying appropriate heat to efficiently wind the raw material around the roll.
[0201]
The toner raw material is dropped from the opening 614 to the vicinity of the end on the roll (RL1) 602-1 side as indicated by an arrow 615 while transmitting the raw material supply feeder 613 from the fixed amount supply machine. The length of the opening of the supply feeder is represented by 616. This length is preferably 1/2 to 4 times the roll radius. If the length is short, the amount of the material to be dropped down from the gap between the two rollers increases before the material to be dropped is melted. If the length is too long, the raw materials are separated during the transportation in the raw material feeder, and uniform dispersion cannot be obtained.
[0202]
Further, as shown by the arrow in FIG. 4, the falling position is set to a point within a range of 20 ° to 80 ° from a point where two rolls of the roll (RL1) 602 are closest to each other. If the angle is smaller than 20 °, the amount of falling from the gap between the two rolls sharply increases. When the angle is 80 ° or more, when the toner powder is dropped, soaring of the toner powder is increased and the surroundings are contaminated. The cover 617 is provided so as to cover an area wider than the opening length 616. The illustration of the cover is omitted in FIG.
[0203]
The toner raw material from the fixed amount feeder 601 falls through the opening 614 while being transmitted through the supply feeder 613. The dropped toner material is dropped near the end on the roll (RL1) 602-1 side. Then, the resin is melted by the heat of 602-1 and the compressive shearing force of the roll (RL2) 603, and the resin is wound around the first half 602-1 of the roll (RL1). The state spreads to the end of the second half 602-2 of the roll (RL1), and the second half 602-2 of the roll (RL2) heated or cooled at a lower temperature than the first half 602-1 of the roll (RL1). Is peeled off from the toner soul. During the above-mentioned processing, the roll 603 is cooled to a room temperature or lower. The clearance between the roll (RL1) 602 and the roll (RL2) 603 is 0.1 to 0.9 mm. In this example, the raw material charging rate was 10 kg / h, the diameter of the rolls (RL1) and (RL2) was 140 mm, and the length was 800 mm.
[0204]
The toner according to the exemplary embodiment is a cylindrical rotating body that has a surface irregularity and that rotates at high speed after melting and kneading the toner composition in order to enable small particle size pulverization and sharpen the distribution on the coarse powder side. And a cylindrical fixed body fitted on the outside of the rotating body with a gap of 0.5 mm to 40 mm and having unevenness on the surface sharing the central axis with the rotating body, and a supply for flowing the toner-ground material The toner is pulverized to a predetermined particle size distribution by a pulverizer having an opening and an outlet for discharging the pulverized toner pulverized product. At this time, before flowing the pulverized material of the toner from the supply port, a means for alleviating the aggregation of the pulverized product of the toner is added, and the pulverized material of the toner is supplied from the supply port and pulverized to a predetermined particle size distribution.
[0205]
As means for alleviating the aggregation of the crushed toner material, an evaporating medium such as water vapor, ethanol, iso-propyl alcohol, and n-butyl may be added to the crushed toner material before flowing the pulverized toner material from the supply port. The purpose is to remove the charge of the powder with alcohol, sec-butyl alcohol, iso-butyl alcohol and the like. This is a method in which mist is supplied to the crushed toner by spraying and mixed or adhered to the crushed toner, and then the crushed material is supplied from a crushing supply port.
[0206]
In addition, a vibrating means may be added to the pulverized toner material before supplying the pulverized toner material from the supply port. The vibrating means includes ultrasonic vibration, vibration vibration, and the like. Before the pulverized product of the toner passes through the pipe and flows from the supply port of the pulverizing unit, a vibration device is provided in the pipe unit, and the pulverized product of the toner flows from the supply port while being dispersed.
[0207]
In addition, there is a method in which before the pulverized material of the toner flows in from the supply port, the inorganic fine powder is supplied to the pulverized material of the toner, mixed with the pulverized material of the toner, and then pulverized through the supply port. The materials described above are suitable as the inorganic fine powder. When the toner is pulverized, the inorganic fine powder is supplied to and mixed with the pulverized toner before flowing the pulverized material of the toner from the supply port, and the pulverized material is pulverized to a predetermined particle size distribution by flowing through the supply port. Take. As a result, the material to be crushed enters the crushing section having the rotating body in a state where the crushed material of the toner is uniformly dispersed, and the crushed material of the toner is uniformly crushed by the vortex generated by the rotating body. Thereby, it is possible to perform the pulverization with a smaller particle size and the pulverization in a state where the coarse powder is sharply cut.
[0208]
At this time, the inorganic fine powder supplied and mixed is preferably silica or titanium oxide fine powder having an average particle size of 8 to 40 nm and a loss on ignition of 0.5 to 25 wt%. Further, silica or titanium oxide fine powder obtained by surface-treating one or more of fatty acid esters, fatty acid amides, and fatty acid metal salts is preferable. Further, the inorganic fine powder is preferably a silica or titanium oxide fine powder obtained by surface-treating silicone oil. In order to alleviate the charge of the pulverized product of the toner, an inorganic fine powder having a polarity opposite to that of the toner base particles is also effective.
[0209]
When the average particle size is smaller than 8 nm, the quantitative cutting becomes unstable. If the average particle size is larger than 40 nm, uniform pulverizability is not improved. If the ignition loss is less than 0.5 wt%, fine powder will be scattered. If the ignition loss is more than 25% by weight, the aggregation of the fine powder becomes strong, and the uniform supply of the pulverized product of the toner deteriorates.
[0210]
The inorganic fine powder adheres to the toner surface in an electrostatic state without being fixed to the toner base. About half or less of the input amount is taken to the bag filter. The supply amount of the inorganic fine powder is preferably about 0.1 to 5% by weight of the supply amount of the pulverized product of the toner.
[0211]
By setting the gap between the convex portion of the rotating body and the convex portion of the fixed body to 0.5 to 40 mm, preferably 0.5 to 10 mm, and more preferably 0.5 to 6 mm, the pulverization efficiency and the spheroidizing effect are improved. Can be enhanced. When the diameter is smaller than 0.5 mm, the contact between the particles and the rotating body or the fixed body is remarkably increased, so that frictional heat is remarkably generated, and the toner is fused at the above-mentioned front end. If it is larger than 40 mm, a vigorous high-speed air flow cannot be generated, and sufficient pulverizability cannot be obtained.
[0212]
When this method is used, the spheroidizing treatment can be performed simultaneously with the pulverization, so that there is a great merit that the manufacturing process can be shortened. According to this method, the toner particles are sharply rounded and have a spherical shape, so that the fluidity is dramatically improved.
[0213]
If the fluidity of the toner is low, unevenness occurs in the solid image area, the triboelectricity decreases, the amount of toner of the opposite polarity increases, and the toner strongly adheres to the non-image area of the photoconductor and cannot be removed, causing a background fog. As a result, the image deteriorates, and the transfer efficiency decreases. When the flowability of the toner is increased by increasing the amount of the external additive silica, the triboelectric charging tends to be uniform, and the background fog is reduced, the image density is increased, and the unevenness of the solid black image portion tends to be eliminated. However, problems such as filming of silica or toner on the photoreceptor and adhesion of silica aggregates to white dots on a solid black image portion occur.
[0214]
Therefore, high fluidity can be obtained with a small amount of added silica, the generation of floating silica is suppressed, and white spots of silica on a solid black image area, silica on an intermediate transfer member and a photoconductor, and toner filming are suppressed. Generation is suppressed. Further, the occurrence of unevenness in the solid black image area seen with low-fluidity toner is suppressed, uniform transferability is obtained, and the occurrence of reverse polarity toner is suppressed to a low level, which is a factor of improving transfer efficiency.
[0215]
Further, at the time of transfer, particularly at high temperature and high humidity, where toner such as characters and lines are concentrated, even when transferred with a predetermined pressing force, due to the high fluidity of the toner, aggregation of the toners hardly occurs, A clear image without any voids can be obtained.
[0216]
An example of the toner pulverizing device of the present embodiment shown in FIG. 5 will be described.
[0219]
The kneaded material 503, to which the kneaded material has passed a mesh diameter of about 1 to 5 mm by coarse pulverization, is fed from the quantitative supply device 508 and sent to the pulverization supply unit by the cooling air 511 supplied by the cooler 509, and the pulverization processing unit Milled at 500. A raw material 503 is supplied from an inlet 504, rotates at a high speed, and has a rotating body 501 having an uneven portion 506 on its surface, and a fixed body 502 having an uneven portion 507 on its surface positioned at a narrow gap from the rotating body 501. The raw material particles are conveyed to the space, and are made into spheres while being pulverized by strong collision with the high-speed airflow generated between the rotating body and the fixed body rotating at high speed. The spheroidized particles 510 exit from the outlet 505 and are sent to the coarse classifier 513, and the coarse particles are sent again to the inlet 504 by the air 511. The product is sent to the cyclone 515 and collected in the collection container 520. 512 is a thermometer, 514 is a bag filter, 516 is an air flow meter, and 517 is a blower.
[0218]
519 is a vibrator vibrator, and 518 is an inorganic fine powder supply device. When separated by coarse powder classification and supplied to the pulverizing section again, it is preferable to supply the inorganic fine powder supply from behind. Thereby, the inorganic fine powder is uniformly mixed at the time of collision with the pulverized material. The medium can be supplied with a volatile solvent instead of the inorganic fine powder. In this embodiment, the grinding conditions (1) the peripheral speed of the rotating body: 130 m / s, the gap between the rotating body and the fixed body: 1.5 mm, the supply amount of the pulverized material of the toner: 5 kg / h, the supply amount of the inorganic fine powder : 0.03 kg / h, cooling air temperature: 0 ° C, discharge section temperature: 45 ° C, grinding conditions (2) Circumferential speed of rotating body: 120 m / s, gap between rotating body and fixed body: 1 mm, pulverized product of toner The supply rate was 5 kg / h, the supply rate of the inorganic fine powder was 0.02 kg / h, the cooling air temperature was 0 ° C., and the discharge section temperature was 40 ° C.
[0219]
In general, emulsion polymerization, suspension polymerization, and the like can also be suitably used as a method for preparing a small particle size toner.
[0220]
In a general emulsion polymerization method, a resin fine particle dispersion containing an ionic surfactant is prepared, mixed with a colorant particle dispersion and a release agent particle dispersion, and the opposite of the ionic surfactant. Aggregation is caused by a polar ionic surfactant to form aggregated particles having a toner diameter, and then heated to a temperature equal to or higher than the glass transition point of the resin fine particles to fuse the aggregated particles, and then washed and dried. The present invention can also be applied to a toner created by the above-described means.
[0221]
Examples of the surfactant used at this time include anionic surfactants such as sulfate ester type, sulfonate type, phosphate ester type and soap type, and cationic type such as amine salt type and quaternary ammonium salt type. Surfactants can be used. It is also effective to use a nonionic surfactant such as polyethylene glycol, alkylphenol ethylene oxide adduct or polyhydric alcohol. As these dispersing means, general ones such as a rotary shearing homogenizer, a ball mill having a medium, a sand mill, and a dyno mill can be used.
[0222]
After the particles are formed, a desired toner can be obtained through an optional washing step, solid-liquid separation step, and drying step. However, the washing step is sufficiently replaced and washed with ion-exchanged water in order to develop and maintain the chargeability. Is preferably applied. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration and the like are preferably used from the viewpoint of productivity. Further, the drying step is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration type fluidized drying and the like are preferably used from the viewpoint of productivity.
[0223]
In the suspension polymerization method, generally, various additives such as a polymerizable monomer, a wax, and a colorant are uniformly dissolved or dispersed, heated, and uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser, or the like. After the composition is formed, the monomer system is dispersed in an aqueous phase at the same temperature as the monomer system containing the dispersion stabilizer using an ordinary stirrer or a homomixer / homogenizer.
[0224]
Preferably, the stirring speed and time are adjusted so that the monomer droplets have a predetermined toner particle size, generally a particle size of 20 μm or less, and thereafter, the particle state is maintained by the action of the dispersion stabilizer, and the particle size is maintained. The stirring may be performed to such an extent that sedimentation is prevented. The polymerization temperature is set at a temperature of 40 ° C. or higher, generally 50 to 80 ° C.
[0225]
At this time, the stirring speed is preferably 30 m / sec or more in order to increase the dispersion of the fixing aid and to obtain a small and uniform particle size distribution of the toner particles containing the fixing aid.
[0226]
After the completion of the reaction, the generated toner particles are collected by washing and filtration, and dried. In the suspension polymerization, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.
[0227]
The dispersion medium used is any suitable stabilizer, as an organic compound, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and salts thereof, starch, inorganic Compounds include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, calcium metasilicate, bentonite, silica, alumina Can be used by dispersing them in an aqueous phase.
[0228]
When an inorganic compound is used in the dispersion stabilizer, the inorganic compound may be generated in an aqueous medium in order to obtain finer particles. For example, in the case of calcium phosphate, it is preferable to mix an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring.
[0229]
For fine dispersion of these stabilizers, 0.001 to 0.1 parts by weight of a surfactant may be used. This is to promote the intended action of the dispersion stabilizer, and specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, Potassium stearate, calcium oleate and the like can be mentioned.
[0230]
2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4 An azo or diazo polymerization initiator such as -methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile can be used.
[0231]
In the developing process of this embodiment, the resistance of the magnetite or ferrite particles coated with resin is 1 × 10 ⁹ ~ 1 × 10 ¹⁴ Mixed with a carrier having a particle size of 30 to 80 μm, and is suitably used for two-component development.
[0232]
An AC bias is applied between the photoconductor and the developing roller together with a DC bias.
[0233]
At this time, the frequency is 1 to 10 kHz, the AC bias is 1.0 to 2.5 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.2 to 1: 2. Is preferred.
[0234]
More preferably, the frequency is 3.5 to 8 kHz, the AC bias is 1.2 to 2.0 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.5 to 1: 1. .8.
[0235]
More preferably, the frequency is 5.5 to 7 kHz, the AC bias is 1.5 to 2.0 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.6 to 1: 1. .8.
[0236]
By using this development process configuration and the toner of the present embodiment, the dots can be faithfully reproduced and the development γ characteristic can be made to be a characteristic. High-quality images and oil-less fixability can be compatible. In addition, even with a high-resistance carrier, charge-up under low humidity can be prevented, and a high image density can be obtained even in continuous use. This is thought to be due to the toner that can exhibit high chargeability, the combined use of the carrier configuration and the AC bias, the adhesion to the carrier can be reduced, the image density can be maintained, fog can be reduced, and dots can be faithfully reproduced. .
[0237]
When the frequency is lower than 1 kHz, dot reproducibility deteriorates, and halftone reproducibility deteriorates. If the frequency is higher than 10 kHz, it is impossible to follow in the development area, and no effect is obtained. In this frequency range, in the two-component development using a high-resistance carrier, the toner acts on the reciprocating action between the carrier and the toner rather than between the developing roller and the photoreceptor, and has an effect of slightly releasing the toner from the carrier. Good reproducibility and halftone reproducibility can be achieved, and high image density can be obtained.
[0238]
When the AC bias is lower than 1.0 kV (pp), the effect of suppressing charge-up cannot be obtained, and when the AC bias is higher than 2.5 kV (pp), fog increases. If the peripheral speed ratio between the photosensitive member and the developing roller is smaller than 1: 1.2 (the developing roller is slowed down), it is difficult to obtain an image density. When the peripheral speed ratio between the photosensitive member and the developing roller is larger than 1: 2 (the developing roller speed increases), toner scattering increases.
[0239]
A carrier for use in two-component development is prepared by providing a resin coating layer on the surface of ferrite particles. Ferrite is Fe ₂ O ₃ With NiO, CuO, CoO, MgO, ZnO, MnCO ₃ , BaCO ₃ , SrCO ₃ Are mixed and used as a raw material. The ferrite particles are prepared by a wet method or a dry method, but a dry method is preferred. In the dry method, raw materials are mixed, pre-fired, pulverized in water with a ball mill or the like, and polyvinyl alcohol, an antifoaming agent, and a dispersant are added as a binder to form a granulating chiller. This chiller is granulated while heating and drying with a spray drier to form granules, and then main firing. The main firing is performed at 900 to 1400 ° C. for 3 to 30 hours, and then crushed and classified to obtain ferrite particles.
[0240]
Known methods such as a spray method and a dipping method are used for the coating layer. The coating amount is 0.1 to 2% by weight of the carrier particle weight. As the resin used for the resin coating layer, a fluorine-based resin or a silicone-based resin is used. As the carbon black to be contained in the resin coating layer, carbon blacks of various production methods are used, and oil furnace carbon yaacetylene black is preferable.
[0241]
For example, 35 mol% of MnO, 15 mol% of MgO, Fe ₂ O ₃ Was crushed by a wet ball mill for 5 hours, mixed and dried at 48.5 mol% and 0.5 mol% of SrCO 3, and then dried and held at 850 ° C. for 1 hour to perform calcination. This was pulverized by a wet ball mill for 7 hours to 3 μm or less. An appropriate amount of a dispersant and a binder were added to the chiller, and the mixture was granulated by a spray drier, dried, and kept in an electric furnace at 1200 ° C. for 4 hours to perform main firing. Thereafter, the resultant was crushed and further classified to obtain a core material of ferrite particles having an average particle size of 50 μm and a particle size distribution of 30 to 70 μm. When the component analysis of the granulated ferrite particles was performed, MnO was 35 mol%, MgO was 14.5 mol%, SrO was 0.5 mol%, and Fe was 0.5 mol%. ₂ O ₃ Was 50 mol%.
[0242]
Using these ferrite particles as a core material, a silicone resin (trade name: SR-2411, solid content: 20 wt%, manufactured by Toray Dow Corning Silicone Co., Ltd.) is dissolved in a toluene solvent, and the carrier core material is fluidized using a fluidized bed. Coating was performed at 0.6 wt%, and baking was performed at 250 ° C. for 3 hours to obtain a resin-coated carrier.
[0243]
The average particle size of the carrier is preferably 30 to 70 μm. When the average particle diameter of the carrier is less than 30 μm, the carrier is easily developed on the photoreceptor, and when the average particle diameter of the carrier is more than 70 μm, the toner holding power of the carrier is weakened, and toner scattering occurs.
[0244]
In the developing process of the present embodiment, an elastic blade such as rubber or metal is brought into contact with an elastic or rigid developing roller with a constant pressure to form a thin layer of toner and is developed by contact or non-contact with the photoconductor. It can be suitably used as a one-component developing method. As a one-component development method, a sponge-based supply roller made of a urethane resin is brought into contact with a development roller made of a silicone resin or a urethane resin with a fixed bite amount, and toner is supplied from the supply roller to the development roller. A thin layer of toner is formed by contacting an elastic rubber or metal stainless steel doctor blade, or by rotating a metal roller against the developing roller against the same direction. Alternatively, a developing method of forming a toner image by applying DC or AC in a non-contact manner is preferably used.
[0245]
At this time, the frequency of the AC bias is 0.5 to 10 kHz, the AC bias is 0.3 to 1.2 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.2 to 1 By setting the ratio to 1.8, dots can be faithfully reproduced, good development γ characteristics can be obtained, and a high-quality image can be realized. Thus, lowland fog and high image density can be obtained. The frequency is 0.5 to 5 kHz, the AC bias is 0.3 to 1.0 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.2 to 1: 1.5. More preferably, the frequency is 0.5 to 2 kHz, the AC bias is 0.5 to 0.9 kV (pp), and the peripheral speed ratio between the photosensitive member and the developing roller is 1: 1.2 to 1: 1.4.
[0246]
At this time, if the frequency is lower than 0.5 kHz, dot reproducibility deteriorates, and halftone reproducibility deteriorates. If the frequency is higher than 10 kHz, it is impossible to follow in the development area, and no effect is obtained. When the AC bias is smaller than 0.3 kV (pp), no solid tracking effect is obtained, and when the AC bias is larger than 1.2 kV (pp), fog increases. If the peripheral speed ratio between the photosensitive member and the developing roller is smaller than 1: 1.2 (the developing roller is slowed down), it is difficult to obtain an image density. When the peripheral speed ratio between the photoconductor and the developing roller is larger than 1: 1.8 (the developing roller speed increases), toner scattering increases.
[0247]
The supply roller and the development roller are rotated in the same direction, and the peripheral speed of the development roller and the supply roller is set to be faster at a ratio of 1: 1 to 0.8: 0.2. The developing roller has a surface area of 9.8 to 9.8 × 10 ² The electrostatic latent image on the photoreceptor is developed by pressing against the pressure of (N). The elastic blade is 5-5 × 10 ² A toner layer is formed by pressing against the developing roller with the pressure of (N).
[0248]
Further, in order to control the amount of toner supplied from the toner reservoir to the amount of toner on the developing roller when the amount of toner is conveyed onto the developing roller, a sponge-shaped supply roller made of urethane resin or the like is used. In this case, a constant bite amount of 0.1 to 1 mm is used to make contact with the developing roller.
[0249]
A sponge-like supply roller made of urethane resin or the like is brought into contact with the developing roller in order to control the amount of toner supplied on the developing roller when the amount of toner supplied from the toner reservoir is transferred onto the developing roller. The configuration provided with is taken. This is an effective means for regulating the toner transport amount to a constant amount.
[0250]
However, in the case of the conventional toner, in the developing configuration, if the toner is used for a long period of time, a defect on the developing roller or an image defect in which a vertical streak is formed on the image due to the adhesion of a foreign matter to the blade is likely to occur. In particular, the use of a binder resin having a low softening property or a toner to which a low melting point release agent is added to improve the color fixing property is more remarkable.
[0251]
In addition, during the long-term continuous use, the amount of toner transported on the developing roller is reduced, and when a solid black image is taken, solid follow-up failure in which the density of the latter half of the image is partially reduced easily occurs. When the charge amount of the toner on the developing roller was measured by a suction method, it was found that the charge amount was greatly reduced. To further pursue, the charge amount of the toner on the supply roller portion has increased significantly.In other words, the decrease in image density does not mean that the charge amount of the toner has decreased, but the supply roller portion before being supplied to the developing roller. This is because the charging capability has increased and the supply capability from the supply roller to the developing roller has decreased. Therefore, a configuration that can secure the image density while preventing toner scattering is required. It is also effective to increase the pressing force of the doctor blade to increase the charging ability of the toner, but the toner is likely to fuse and damage the developing roller.
[0252]
Therefore, it has been found that by employing the toner configuration of the present embodiment, it is possible to prevent the occurrence of vertical streaks on the developing roller, poor solid followability, and fusion of toner without sacrificing the fixing characteristics.
[0253]
This enables uniform dispersion in the resin, stabilizes the charge distribution, suppresses overcharging of the toner at the supply roller, stabilizes the fluidity, and improves the followability of a solid image. By the uniform dispersion, the fluidity of the toner can be maintained, the toner can be smoothly transported on the developing roller, and the transport state can be always stabilized. In particular, it is highly effective in stabilizing the transport state under high humidity. At this time, the charge amount of the toner on the developing roller by the suction type Faraday cage method is preferably | 5 | to | 45 | μC / g. If it is less than | 5 | μC / g, toner scattering increases. When | 45 | μC / g or more, it is difficult to obtain an image density.
[0254]
In the measurement of the toner charge amount by the suction type Faraday cage method, the toner on the developing roller is sucked while rotating, and the sucked toner is collected on a filter to obtain the weight W (g). Further, the amount of charge when the charged toner moves during suction is measured by measuring the voltage V (V) induced in the capacitor, and Q (μC / g) = C (F) × V (V) / W (g) From the charge amount.
[0255]
In addition, in order to form a color image at high speed, the present embodiment has a plurality of toner image forming stations including a photoconductor, a charging unit, and a toner carrier, and visualizes an electrostatic latent image formed on the image carrier. The primary transfer process of transferring the imaged toner image to the transfer member by bringing an endless transfer member into contact with the image carrier is sequentially performed, and a multi-layer transfer toner image is formed on the transfer member. A first transfer process in which a secondary transfer process is performed to collectively transfer the multi-layered toner image formed on the transfer body to a transfer medium such as paper or OHP. When the distance from the transfer position to the second primary transfer position is d1 (mm) and the peripheral speed of the photosensitive member is v (mm / s), the transfer position configuration satisfies d1 / v ≦ 0.65. There is, for example, the first color yellow toner After the primary transfer, the time required for the next transfer of the magenta toner of the second color is extremely short, so that the charge on the transfer member or the charge on the transferred toner is hardly alleviated, and the magenta toner is transferred onto the yellow toner. When transferring the toner, the magenta toner is repelled by the charge action of the yellow toner, which causes a problem that the transfer efficiency is reduced and characters are missing during transfer. Further, at the time of primary transfer of the cyan toner of the third color, when the toner is transferred onto the previous yellow and magenta toners, scattering of the cyan toner, transfer failure, and omission during transfer occur remarkably. Further, the toner having a specific particle diameter is selectively developed during repeated use, and when the fluidity of each toner particle is significantly different, the chance of frictional charging is different, so that the charge amount varies, and the transferability is further deteriorated. Will be invited.
[0256]
Therefore, by adopting the toner configuration of the present embodiment, the internal additives such as wax in the resin are uniformly dispersed, the charge distribution is stabilized, the toner is overcharged by the supply roller, and the fluidity fluctuation is suppressed. Therefore, it is possible to prevent a decrease in transfer efficiency and a dropout of characters at the time of transfer without sacrificing the fixing characteristics.
[0257]
Embodiment 11: Cleanerless process
Further, in this embodiment, the electrophotography basically includes a cleanerless process for performing the next charging, exposure, and developing processes without having a cleaning process step of recovering the toner remaining on the photoconductor after the transfer process by cleaning. It is suitable for use in equipment.
[0258]
By using the toner of the present embodiment, aggregation of the toner is suppressed, overcharging is prevented, chargeability is stabilized, and high transfer efficiency can be obtained. Further, due to the improvement in uniform dispersibility in the resin, the good charging property, and the releasability of the material, the toner remaining in the non-image area can be favorably collected by development. Therefore, there is no development memory in which the image pattern before the non-image portion remains.
[0259]
The present embodiment is suitably used for an electrophotographic apparatus having a fixing process in which a belt-type fixing medium is used as a unit for fixing toner. As the belt, a heat-resistant belt such as a nickel electroformed belt or a polyimide belt having heat resistance and flexibility is used. In order to improve the releasability, the surface layer is made of silicone rubber, fluoro rubber, or fluoro resin. Until now, these fixing belts have been coated with release oil to prevent offset. The use of a toner having releasability without using oil eliminates the need to apply a release oil. However, if the release oil is not applied, the toner tends to be charged, and if an unfixed toner image approaches the belt, the toner may fly due to the influence of the charging. In particular, it easily occurs under low temperature and low humidity. Also, when the toner adds a certain amount of high molecular weight component to prevent high temperature offset and has a certain elastic element, the paper with a thin vertical line pattern of the toner is separated from the belt with a large curvature by the tip. May be brought to the belt. Further, compared to the conventional rigid fixing roller, in the case of an elastic belt type, there is a problem in that the life is shortened due to scratches due to oillessness.
[0260]
Thus, by using the toner of the present embodiment, it is possible to prevent the occurrence of offset without using oil, and to obtain high color translucency. Further, the overcharging property of the toner can be suppressed, and the flying of the toner due to the charging action with the belt can be suppressed. Further, it can be prevented by the effect of the molecular weight distribution and the slipperiness of the offset toner whose leading end portion is brought to the belt at the time of separation from the belt.
[0261]
Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to this.
[0262]
Table 1 shows the characteristics of the binder resin used in the examples. As the resin, a polyester resin containing bisphenol A propyl oxide adduct, terephthalic acid, trimellitic acid, succinic acid, and fumaric acid as main components was used, and a resin having different thermal characteristics depending on the blending ratio and polymerization conditions was used.
[0263]
[Table 1]

[0264]
Mnf is the number average molecular weight of the binder resin, Mwf is the weight average molecular weight of the binder resin, Mzf is the Z average molecular weight of the binder resin, Wmf is the ratio Mwf / Mnf between the weight average molecular weight Mwf and the number average molecular weight Mnf, and Wzf is The ratio Mzf / Mnf between the Z-average molecular weight Mzf and the number-average molecular weight Mnf of the binder resin, and AV indicates the resin acid value.
[0265]
(Table 2), (Table 3) and (Table 4) show the waxes used in this example and the physical properties thereof. Mnr indicates the number average molecular weight of the wax, Mwr indicates the weight average molecular weight of the wax, and Mzr indicates the Z average molecular weight of the wax. Tw (° C.) indicates the melting point by the DSC method, Ct (%) indicates the volume increase rate (%) at the melting point + 10 ° C., and Ck (wt%) indicates the loss on heating at 220 ° C.
[0266]
[Table 2]

[0267]
[Table 3]

[0268]
[Table 4]

[0269]
Table 5 shows the pigments used in this example.
[0270]
[Table 5]

[0271]
Table 6 shows the charge control agents used in this example and their physical properties.
[0272]
As a metal salt of a salicylic acid derivative, examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group and a tert-butyl group. And the like. Examples of the metal Y include zinc, nickel, cobalt, copper, and chromium, and zinc and chromium are preferable. Examples of metal salts of benzylic acid derivatives include R ¹ ~ R ⁴ Is a benzene ring, and examples of the alkali metal X include lithium, sodium, and potassium, with potassium being preferred.
[0273]
[Table 6]

[0274]
(Table 7) shows the external additives used in this example. The charge amount is measured by a blow-off method of triboelectric charging with a non-coated ferrite carrier. In an environment of 25 ° C. and 45% RH, 50 g of a carrier and 0.1 g of silica or the like are mixed in a 100 ml polyethylene container, and the mixture is rotated vertically for 100 minutes. ^-1 After stirring for 5 minutes and 30 minutes at a speed of 0.3 g, 0.3 g was collected, and nitrogen gas 1.96 × 10 ⁴ (Pa) for 1 minute.
[0275]
In the case of positive chargeability, it is preferable that the value for 5 minutes after stirring for 5 minutes is +100 to +800 μC / g, and the value for 30 minutes after stirring for 30 minutes is +50 to +400 μC / g. Silica having a charge amount at 30 minutes of 40% or more of a charge amount at 5 minutes is preferable. If the rate of decrease is large, the change in the charge amount during long-term continuous use is large, and a constant image cannot be maintained.
[0276]
It is preferable that the value for 5 minutes is -100 to -800 [mu] C / g and the value for 30 minutes is -50 to -600 [mu] C / g. Silica having a high charge amount can exhibit its function with a small amount of addition.
[0277]
[Table 7]

[0278]
The kneading conditions in this example are shown in (Table 8). Trj1 (° C.) is the heating temperature of the first half of the roll (RL1), Trk1 (° C.) is the heating temperature of the second half of the roll (RL1), Tr2 (° C.) the heating temperature of the roll (RL2), and Rw1 is the roll (RL1). The rotation speed Rw2 of the roll (RL2) indicates the rotation speed of the roll (RL2), the load current value during rotation of the roll (RL1) is Dr1, and the load current value of the roll (RL2) is Dr2. The feed amount was 15 kg / h, the diameter of the rolls (RL1) and (RL2) was 140 mm, and the length was 800 mm.
[0279]
[Table 8]

[0280]
(Table 9) and (Table 10) show the grinding conditions in this example.
[0281]
The inorganic fine powder to be supplied before pulverization, the supply amount thereof, vibrator vibration application, and solvent spraying are applied.
[0282]
[Table 9]

[0283]
[Table 10]

[0284]
(Table 11) and (Table 12) show the toner material composition and physical properties used in this example.
[0285]
[Table 11]

[0286]
[Table 12]

[0287]
In the drawing, Ss is a specific surface area value of the pulverized toner, St is a value represented by St = 6 / (true specific gravity of toner × volume average particle diameter), and SSt is St to Ss (pulverized toner). (Specific surface area value).
[0288]
The kneading PCM 30 is a conventional twin screw extruder and has a kneading temperature of 110 ° C. and a rotation speed of 200 min. ^-1 At a supply rate of 5 kg / h.
[0289]
As for the mixing ratio of the pigment, the charge control agent, and the wax, the mixing ratio (parts by weight) relative to 100 parts by weight of the binder resin is shown in parentheses. The amount of the external additive is shown as a blending amount (parts by weight) based on 100 parts by weight of the toner matrix. External addition processing was performed by using a stirring blade Z0S0 type and a rotation speed of 2,000 min in the FM20B. ^-1 The processing time was 5 min and the input amount was 1 kg.
[0290]
Tables 13 and 14 show the molecular weight characteristics of the toner after the kneading treatment in this example. The toners were compared and evaluated with the magenta toners TM1 to TM7. Similar results are obtained with yellow, cyan, and black toners. Mnv is the number average molecular weight of the toner, Mwv is the weight average molecular weight of the toner, Wmv is the ratio Mwv / Mnv of the weight average molecular weight Mwv of the toner and the number average molecular weight Mnv, and Wzv is the ratio of the Z average molecular weight Mzv of the toner and the number average molecular weight Mnv. Mzv / Mnv is shown.
[0291]
In the molecular weight distribution, ML is a molecular weight value showing a maximum molecular weight peak on the low molecular weight side, MH is a molecular weight value showing a molecular weight maximum peak on the high molecular weight side, Sm is Hb / Ha, SK1 is M10 / M90, and SK2 is (M10-M90). / M90.
[0292]
[Table 13]

[0293]
[Table 14]

[0294]
(Example 1)
FIG. 6 is a sectional view showing the configuration of the image forming apparatus for forming a full-color image used in the present embodiment. In FIG. 6, an outer casing of the color electrophotographic printer is omitted. Inspection and maintenance of the transfer belt unit 2 in the printer, inspection and maintenance inside the printer such as when a paper jam occurs, etc. are performed by lowering and opening the front plate to largely release the inside of the printer. The transfer belt unit 17 is designed to be attached and detached in a direction parallel to the rotation axis generatrix direction of the photoconductor.
[0295]
The transfer belt unit 17 includes a transfer belt 12, a first color (yellow) transfer roller 10Y made of an elastic material, a second color (magenta) transfer roller 10M, a third color (cyan) transfer roller 10C, and a fourth color (black). A transfer roller 10K, a drive roller 11 made of an aluminum roller, a second transfer roller 14 made of an elastic body, a second transfer driven roller 13, a belt cleaner blade 16 for cleaning the toner image remaining on the transfer belt 12, and opposed to the cleaner blade. The roller 15 is provided at a position where the roller 15 is to be driven.
[0296]
At this time, the distance from the first color (Y) transfer position to the second color (M) transfer position is 35 mm (the second color (M) transfer position to the third color (C) transfer position, the third color (C) The transfer position of the fourth color (K) is also the same from the transfer position), and the peripheral speed of the photoconductor is 100 mm / s.
[0297]
The transfer belt 12 is used by kneading a conductive filler in an insulating polycarbonate resin and forming a film with an extruder. In the present embodiment, a film obtained by adding 5 parts by weight of conductive carbon (for example, Ketjen black) to 95 parts by weight of a polycarbonate resin (for example, Iupilon Z300 manufactured by Mitsubishi Gas Chemical) as an insulating resin was used. The surface is coated with a fluororesin, the thickness is about 100 μm, and the volume resistance is 10 ⁷ -10 ¹² Ω · cm, surface resistance is 10 ⁷ -10 ¹² Ω / □. Another purpose is to improve dot reproducibility. The reason for this is that the transfer belt 12 can be effectively prevented from being loosened or accumulated electric charge due to long-term use, and the surface is coated with a fluorine resin because toner filming on the transfer belt surface due to long-term use Is to be effectively prevented. Volume resistance is 10 ⁷ If it is smaller than Ω · cm, retransfer is likely to occur and 10 ¹² If it is larger than Ω · cm, the transfer efficiency deteriorates.
[0298]
The first transfer roller is a carbon conductive urethane roller having an outer diameter of 10 mm and a resistance value of 10 mm. ² -10 ⁶ Ω. At the time of the first transfer operation, the first transfer roller 10 is pressed against the photosensitive member 1 via the transfer belt 12 with a pressing force of 1.0 to 9.8 (N), and the toner on the photosensitive member is transferred onto the belt. Is done. Resistance value is 10 ² If it is smaller than Ω, retransfer is likely to occur. 10 ⁶ If it is larger than Ω, transfer failure tends to occur. If it is smaller than 1.0 (N), transfer failure occurs, and if it is larger than 9.8 (N), missing characters are caused.
[0299]
The second transfer roller 14 is a carbon conductive urethane roller having an outer diameter of 15 mm and a resistance value of 10 mm. ² -10 ⁶ Ω. The second transfer roller 14 is pressed against the transfer roller 13 via the transfer belt 12 and a transfer medium 19 such as paper and OHP. The transfer roller 13 is configured to be rotatable following the transfer belt 12. In the secondary transfer, the second transfer roller 14 and the opposing transfer roller 13 are pressed against each other with a pressing force of 5.0 to 21.8 (N), and the toner is transferred from the transfer belt onto a recording material 19 such as paper. You. Resistance value is 10 ² If it is smaller than Ω, retransfer is likely to occur. 10 ⁶ If it is larger than Ω, transfer failure tends to occur. If it is smaller than 5.0 (N), transfer failure occurs, and if it is larger than 21.8 (N), the load increases and jitter tends to occur.
[0300]
In FIG. 6, four image forming units 18Y, 18M, 18C and 18K for each color of yellow (Y), magenta (M), cyan (C) and black (B) are arranged in series as shown in the figure. Have been.
[0301]
Since each of the image forming units 18Y, 18M, 18C, and 18K is made of the same components except for the developer contained therein, the image forming unit 18Y for Y will be described to simplify the description, and the unit for other colors will be described. Is omitted.
[0302]
The image forming unit is configured as follows. 1 is a photoreceptor, 3 is a pixel laser signal light, and 4 is a developing roller made of silicone rubber having a JIS-A hardness of 60 ° and having an outer diameter of 12 mm, which is pressed against the photoreceptor with a force of 21 N and rotates in the direction of the arrow. I do. Reference numeral 6 denotes a supply roller made of a conductive urethane sponge having an outer diameter of 10 mm, and supplies the toner in the toner hopper to the developing roller. A metal blade 5 forms a toner layer on the developing roller. Although a power source is omitted, a DC of -230 V and an AC voltage of 500 V (pp) at a frequency of 1 kHz are applied to the developing roller 4. A DC bias of −330 V is applied to the supply roller 6.
[0303]
Reference numeral 2 denotes a charging roller made of epichlorohydrin rubber having an outer diameter of 12 mm to which a DC bias of -1 kV is applied. The surface of the photoconductor 1 is charged to -450V. Reference numeral 8 denotes a cleaner, 9 denotes a waste toner box, and 7 denotes a toner.
[0304]
The paper is conveyed from below the transfer unit 17, and the paper 19 is fed by a paper feed roller (not shown) to a nip portion where the transfer belt 12 and the second transfer roller 14 are pressed. A transport path is formed.
[0305]
The toner on the transfer belt 12 is transferred to the paper 19 by + 1300V applied to the second transfer roller 14, and includes a fixing roller 201, a pressure roller 202, a fixing belt 203, a heating medium roller 204, and an induction heater unit 205. The sheet is conveyed to a fixing unit, where it is fixed.
[0306]
FIG. 8 shows the fixing process diagram. A belt 203 is hung between the fixing roller 201 and the heat roller 204. A predetermined load is applied between the fixing roller 201 and the pressure roller 202, and a nip is formed between the belt 203 and the pressure roller 202. An induction heater 205 including a ferrite core 206 and a coil 207 is provided on the outer peripheral surface of the heat roller 204, and a temperature sensor 208 is disposed on the outer surface.
[0307]
The belt has a structure in which 30 μm Ni is used as a base, silicone rubber is 150 μm thereon, and a PFA tube 30 μm is further superimposed thereon.
[0308]
The pressure roller 202 is pressed against the fixing roller 201 by a pressure spring 209. The recording material 211 having the toner 210 moves along the guide plate 212.
[0309]
The fixing roller 201 as a fixing member has a silicone rubber having a rubber hardness (JIS-A) of 20 degrees according to JIS standard on a surface of an aluminum hollow roller core 213 having a length of 250 mm, an outer diameter of 14 mm, and a thickness of 1 mm. An elastic layer 214 having a thickness of 3 mm is formed. A silicone rubber layer 215 is formed thereon with a thickness of 3 mm, and has an outer diameter of about 20 mm. It rotates at 100 mm / s by receiving a driving force from a driving motor (not shown).
[0310]
The heat roller 204 is formed of a hollow pipe having a thickness of 1 mm and an outer diameter of 20 mm. The surface temperature of the fixing roller was controlled to 170 ° C. using a thermistor.
[0311]
The pressing roller 202 as a pressing member has a length of 250 mm and an outer diameter of 20 mm. In this method, a 2 mm thick elastic layer 217 made of silicone rubber having a rubber hardness (JIS-A) of 55 degrees according to JIS standard is provided on the surface of a hollow roller core 216 made of aluminum having an outer diameter of 16 mm and a thickness of 1 mm. . The pressure roller 202 is rotatably installed, and forms a nip width of 5.0 mm between the pressure roller 202 and the fixing roller 201 by a spring-loaded spring 209 on one side 147N.
[0312]
Hereinafter, the operation will be described. In the full-color mode, all the first transfer rollers 10 of Y, M, C, and K are pushed up and press the photosensitive member 1 of the image forming unit via the transfer belt 12. At this time, a DC bias of +800 V is applied to the first transfer roller. An image signal is sent from the laser beam 3 and is incident on the photoreceptor 1 whose surface is charged by the charging roller 2 to form an electrostatic latent image. The toner 7 on the developing roller 4 that contacts the photoconductor 1 and rotates in the opposite direction visualizes the electrostatic latent image formed on the photoconductor 1.
[0313]
At this time, the image forming speed of the image forming unit 18Y (100 mm / s equal to the peripheral speed of the photoconductor) and the moving speed of the transfer belt 12 are such that the photoconductor speed is 0.5 to 1.5% slower than the transfer belt speed. It is set as follows.
[0314]
In the image forming step, the Y signal light 3Y is input to the image forming unit 18Y, and an image is formed by the Y toner. At the same time as the image formation, the Y toner image is transferred from the photoreceptor 1Y to the transfer belt 12 by the operation of the first transfer roller 10Y. At this time, a DC voltage of +800 V was applied to the first transfer roller 10Y.
[0315]
With a time lag between the first transfer of the first color (Y) and the first transfer of the second color (M), the M signal light 3M is input to the image forming unit 18M, and an image is formed by the M toner. At the same time as the image formation, the M toner image is transferred from the photoconductor 1M to the transfer belt 12 by the operation of the first transfer roller 10M. At this time, the M toner is transferred onto the first color (Y) toner. Similarly, an image is formed with C (cyan) and K (black) toners, and a YMCK toner image is formed on the transfer belt 12 by the operation of the first transfer rollers 10C and 10K simultaneously with the image formation. This is a so-called tandem system.
[0316]
The four color toner images were superposed on the transfer belt 12 so as to match in position, and a color image was formed. After the transfer of the last K toner image, the toner images of the four colors are collectively transferred to paper 19 sent from a paper feed cassette (not shown) by the action of the second transfer roller 14 at the same time. At this time, the transfer roller 13 was grounded, and a DC voltage of +1.3 kV was applied to the second transfer roller 14. The toner image transferred to the paper was fixed by the fixing roller pair 201 and 202. The paper was then discharged out of the apparatus via a discharge roller pair (not shown). The transfer residual toner remaining on the intermediate transfer belt 12 is cleaned by the action of the cleaning blade 16 to prepare for the next image formation.
[0317]
FIG. 7 shows a tandem system in which the paper 19 is transported onto the paper transport belt 17 without performing primary transfer to the belt, and the toner on the OPC is directly transferred.
[0318]
Table 15 shows the results of image output using the electrophotographic apparatus of FIG. In Table 16, the state of poor transfer at the character portion in a full-color image in which three colors of toner overlap, and the wrapping property of the paper around the fixing belt during fixing were evaluated.
[0319]
[Table 15]

[0320]
[Table 16]

[0321]
When an image was formed using the toner produced as described above by the image forming apparatus shown in FIG. 6, the solid black image was uniform without any horizontal line disturbance, toner scattering, and missing characters. An extremely high-resolution and high-quality image reproducing even the image line of / mm was obtained, and a high-density image having an image density of 1.3 or more was obtained. Also, no background fogging of the non-image portion occurred. Furthermore, even in a long-term durability test of 10,000 A4 sheets, both fluidity and image density showed little change and stable characteristics. In addition, the uniformity of a solid image taken at the time of development was good. There is no development memory. No abnormal image of vertical streaks occurred even during continuous use. Also, in the transfer, the hollow portion was at a practically acceptable level, and the transfer efficiency was about 98%. In addition, filming of the toner on the photosensitive member and the transfer belt was at a level having no practical problem. No transfer belt cleaning failure occurred. Further, the toner is not disturbed at the time of fixing and the toner jumping hardly occurs. Also, in a cleaner process in which the residual toner at the time of transfer is recovered in development without using the cleaning blade 8, the recovery can be performed smoothly, and the history of the previous image does not remain. Also, no transfer failure occurred in the three-color superposed full-color image, and no paper wrapped around the fixing belt during fixing. Similar results were obtained with the image forming apparatus shown in FIG.
[0322]
However, the toner of tm7, ty7, tc7, and tb7 caused filming and transfer failure of the photoconductor, scattering of characters at the time of transfer, and a lot of fogging. Filming of the transfer belt and cleaning failure also occurred. When the entire solid image was taken at the time of development, blurring occurred in the latter half. During continuous use, the wax was fused to the developing blade, and an abnormal image of vertical streaks occurred. At the time of image output of three-color superposition, paper wrapping around the fixing belt occurred. Toner jump occurred during fixing.
[0323]
Next, (Table 17) shows the amount of adhesion to OHP paper 1.2 g / cm. ² The above solid image was subjected to a non-offset test with a fixing device using a belt not coated with oil at a process speed of 100 mm / s. OHP jam did not occur in the fixing nip portion. In a solid green image of plain paper, no offset occurred at all up to the 122,000th sheet. Even if oil is not applied to a silicone or fluorine fixing belt, no surface deterioration phenomenon of the belt is observed.
[0324]
The transmittance and the offset property at a high temperature were evaluated. The process speed was 100 mm / s, the fixing temperature was 180 ° C., and the transmittance was 700 nm with a spectrophotometer U-3200 (Hitachi, Ltd.). The results of fixability, offset resistance and storage stability are shown.
[0325]
[Table 17]

[0326]
The OHP light transmissivity was 80% or more, and the non-offset temperature range was 40 to 60K, indicating a good fixing property in a fixing roller using no oil. Aggregation was hardly observed at 60 ° C. for 5 hours.
[0327]
However, the toner of tm7 had a hardening in the storage stability test, and the non-offset temperature range was narrow.
[0328]
【The invention's effect】
As described above, compatibility of the developing property and the transfer property can be achieved by adjusting the external additive formulation to the specific small particle diameter toner to which the wax is added. Further, it is possible to achieve high transfer efficiency, high transfer quality and high image quality without oil transfer in the transfer process of the tandem system, and prevention of dropout or scattering during transfer, and high transfer efficiency. Filming of the photoreceptor and the transfer member can be prevented even in long-term use under high humidity. The cleaning property of the transfer member can be improved. Even in a cleanerless process that does not use a cleaning blade or the like, the transfer residual toner can be collected smoothly, and the history of the previous image can be prevented. Furthermore, even without applying oil, it is possible to realize oilless fixing that prevents offset properties while maintaining high OHP translucency.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a toner melt-kneading process used in an embodiment of the present invention.
FIG. 2 is a plan view of a toner melt-kneading process used in an embodiment of the present invention.
FIG. 3 is a front view of a toner melt-kneading process used in an embodiment of the present invention.
FIG. 4 is a cross-sectional view of a toner melt-kneading process used in an embodiment of the present invention.
FIG. 5 is a configuration diagram of a toner crushing process used in an embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a configuration of an image forming apparatus used in an embodiment of the present invention.
FIG. 7 is a cross-sectional view illustrating a configuration of an image forming apparatus used in an embodiment of the present invention.
FIG. 8 is a sectional view showing a configuration of a fixing unit used in the embodiment of the present invention.
[Explanation of symbols]
1 Photoconductor
3 Laser signal light
4 Developing roller
5 blade
10 First transfer roller
12 Transfer belt
14 Second transfer roller
13 Drive tension roller
17 Transfer belt unit
18B, 18C, 18M, 18Y image forming unit
18 Image forming unit group
201 fusing roller
202 pressure roller
203 fixing belt
205 Induction heater
206 Ferrite core
207 coil
602 roll (RL1)
603 roll (RL2)
604 Melted film of toner wrapped around roll (RL1)
605 Heat medium inlet
606 Heat medium outlet

Claims (21)

The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. A particle size distribution configuration in which a content of .17 μm or less is contained by 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained by 35% by volume or less;
A toner characterized in that 2.5 to 5.3 parts by weight of an inorganic fine powder having an average particle diameter of 6 to 120 nm is externally added to 100 parts by weight of toner base particles. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. The content of .17 μm or less is 5 to 35% by number, the toner particles having a particle size of 6.35 to 10.1 μm are contained at 30% by volume or less, and the content of 8 μm or more in the number distribution is 1 volume. % Or less, and
A toner characterized in that 2.5 to 5.3 parts by weight of an inorganic fine powder having an average particle diameter of 6 to 120 nm is externally added to 100 parts by weight of toner base particles. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. A particle size distribution configuration in which a content of .17 μm or less is contained by 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained by 35% by volume or less;
The inorganic fine powder having an average particle diameter of 6 nm to 20 nm is 1.0 to 2.5 parts by weight based on 100 parts by weight of the toner base particles, and the inorganic fine powder having an average particle diameter of 30 nm to 120 nm is 1 to 100 parts by weight of the toner base particles. 0.5 to 2.8 parts by weight of at least an external additive. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. The content of .17 μm or less is 5 to 35% by number, the toner particles having a particle size of 6.35 to 10.1 μm are contained at 30% by volume or less, and the content of 8 μm or more in the number distribution is 1 volume. % Or less, and
1.0 to 2.5 parts by weight of an inorganic fine powder having an average particle diameter of 6 nm to 20 nm with respect to 100 parts by weight of the toner base particles;
A toner characterized in that at least 1.5 to 2.8 parts by weight of an inorganic fine powder having a thickness of 30 nm to 120 nm is externally added to 100 parts by weight of toner base particles. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. A particle size distribution configuration in which a content of .17 μm or less is contained by 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained by 35% by volume or less;
An inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt%, 1.0 to 2.5 parts by weight based on 100 parts by weight of the toner base particles;
At least 1.5 to 2.8 parts by weight of an inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% with respect to 100 parts by weight of the toner base particles is at least externally added. A toner characterized by the following. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. The content of .17 μm or less is 5 to 35% by number, the toner particles having a particle size of 6.35 to 10.1 μm are contained at 30% by volume or less, and the content of 8 μm or more in the number distribution is 1 volume. % Or less, and
An inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt%, 1.0 to 2.5 parts by weight based on 100 parts by weight of the toner base particles;
At least 1.5 to 2.8 parts by weight of an inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% with respect to 100 parts by weight of the toner base particles is at least externally added. A toner characterized by the following. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. A particle size distribution configuration in which a content of .17 μm or less is contained by 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained by 35% by volume or less;
1.8 to 4 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 120 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles;
At least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 6 nm to 120 nm and a loss on ignition of 0.5 to 25 wt% is externally added to 100 parts by weight of the toner base particles. A toner characterized in that: The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. The content of .17 μm or less is 5 to 35% by number, the toner particles having a particle size of 6.35 to 10.1 μm are contained at 30% by volume or less, and the content of 8 μm or more in the number distribution is 1 volume. % Or less, and
1.8 to 4 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 120 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles;
At least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 6 nm to 120 nm and a loss on ignition of 0.5 to 25 wt% is externally added to 100 parts by weight of the toner base particles. A toner characterized in that: The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. A particle size distribution configuration in which a content of .17 μm or less is contained by 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained by 35% by volume or less;
0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles;
1.2 to 2.0 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles;
At least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% is externally added to 100 parts by weight of the toner base particles. A toner characterized in that: The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. The content of .17 μm or less is 5 to 35% by number, the toner particles having a particle size of 6.35 to 10.1 μm are contained at 30% by volume or less, and the content of 8 μm or more in the number distribution is 1 volume. % Or less, and
0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles;
1.2 to 2.0 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles;
At least 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% is externally added to 100 parts by weight of the toner base particles. A toner characterized in that: The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. A particle size distribution configuration in which a content of .17 μm or less is contained by 5 to 35% by number, and toner particles having a particle size of 6.35 to 10.1 μm are contained by 35% by volume or less;
0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles;
1.2 to 2.0 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles;
Externally adding 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% with respect to 100 parts by weight of the toner base particles. A toner which has been subjected to an external addition process. The volume average particle diameter of the toner containing at least the binder resin, the colorant, and the wax is 3.5 to 5.5 μm, the content of 5.04 μm or less in the number distribution is 60% by number or more, and 3% in the number distribution. The content of .17 μm or less is 5 to 35% by number, the toner particles having a particle size of 6.35 to 10.1 μm are contained at 30% by volume or less, and the content of 8 μm or more in the number distribution is 1 volume. % Or less, and
0.8 to 2 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 6 nm to 20 nm and a loss on ignition of 0.5 to 25 wt% based on 100 parts by weight of the toner base particles;
1.2 to 2.0 parts by weight of a negatively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% based on 100 parts by weight of the toner base particles;
Externally adding 0.5 to 1.5 parts by weight of a positively chargeable inorganic fine powder having an average particle diameter of 30 nm to 120 nm and a loss on ignition of 0.1 to 23 wt% with respect to 100 parts by weight of the toner base particles. A toner which has been subjected to an external addition process. Specific surface area ratio SSt with specific surface area value St (St = 6 / (true specific gravity * volume average particle diameter)) equivalent to a true sphere converted from volume average particle diameter (SSt = (St / specific surface area value of pulverized toner) The toner according to any one of claims 1 to 12, wherein ()) is from 0.4 to 0.9. The toner according to any one of claims 1 to 12, wherein the inorganic fine powder comprises silica or titanium oxide fine powder obtained by surface-treating at least one of a fatty acid ester, a fatty acid amide, and a fatty acid metal salt. The toner according to any one of claims 1 to 12, wherein the inorganic fine powder includes silica or titanium oxide fine powder obtained by surface-treating silicone oil. The binder resin has an acid value of 1 to 40 mgKOH / g, and the wax has a number average molecular weight of 100 to 5000, a weight average molecular weight of 200 to 10,000, at least in a molecular weight distribution in gel permeation chromatography (GPC). The ratio of the weight average molecular weight to the number average molecular weight (weight average molecular weight / number average molecular weight) is 1.01 to 8, the ratio of the Z average molecular weight to the number average molecular weight (Z average molecular weight / number average molecular weight) is 1.02 to 10, The ester wax according to any one of claims 1 to 12, comprising an ester wax having at least one molecular weight maximum peak in a region of a molecular weight of 5 × 10 ² to 1 × 10 ⁴ , an iodine value of 25 or less, and a saponification value of 30 to 300. The toner as described in the above. The binder resin has an acid value of 1 to 40 mgKOH / g, and the wax is at least 5 to 100 carbon atoms by reaction with a long-chain alkyl alcohol, an unsaturated polycarboxylic acid or an anhydride thereof, and a hydrocarbon wax. The toner according to claim 1, further comprising a wax having an acid value of 5 to 80 mg KOH / g, a melting point of 90 to 120 ° C., and a penetration at 25 ° C. of 4 or less. The binder resin has an acid value of 1 to 40 mgKOH / g, and the wax is a hydroxystearic acid derivative, a glycerin fatty acid ester, a glycol fatty acid ester, a polyhydric alcohol fatty acid ester of a sorbitan fatty acid ester, a meadow foam oil derivative, a jojoba oil. The toner according to any one of claims 1 to 12, comprising one or more oil derivatives. The binder resin is a saturated or monovalent unsaturated aliphatic amide having an acid value of 1 to 40 mgKOH / g and a wax having a melting point of 70 to 110 ° C. and having 16 to 24 carbon atoms. The toner according to claim 1, comprising one or more of alkylene bis fatty acid amides of divalent unsaturated fatty acids. An electrostatic latent image formed on the image carrier, comprising a plurality of toner image forming stations including at least an image carrier, a charging unit for forming an electrostatic latent image on the image carrier, and a toner carrier. 20. The toner image visualized by the toner according to any one of 1 to 19, and the toner image obtained by visualizing the electrostatic latent image is transferred to the transfer member by bringing an endless transfer member into contact with the image carrier. A secondary transfer process in which a primary transfer process is sequentially and sequentially executed to form a multi-layered transfer toner image on the transfer body, and thereafter, the multi-layered toner image formed on the transfer body is collectively transferred to a transfer medium; Wherein the transfer process is performed by a distance from a first primary transfer position to a second primary transfer position, or a second primary transfer position to a third primary transfer position. Distance to or the third primary rotation When the distance from the position to the fourth primary transfer position is d1 (mm) and the peripheral speed of the photoconductor is v (mm / s), the configuration satisfies the condition of d1 / v ≦ 0.65 (sec). An image forming apparatus, comprising: An electrostatic latent image formed on the image carrier, comprising a plurality of toner image forming stations including at least an image carrier, a charging unit for forming an electrostatic latent image on the image carrier, and a toner carrier. 20. A transfer system configured to execute a transfer process of sequentially and continuously transferring the toner images, which are visualized by the toner according to any one of 1 to 19 and the electrostatic latent images are visualized, to a transfer medium. Wherein the transfer process includes a distance from the first transfer position to the second transfer position, a distance from the second transfer position to the third transfer position, or a distance from the third transfer position to the fourth transfer position. When the distance to the transfer position is d1 (mm) and the peripheral speed of the photoconductor is v (mm / s), the configuration satisfies the condition of d1 / v ≦ 0.65 (sec). Image forming device.

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