JP3586101B2 - Dry toner and image forming method - Google Patents

Description

【００３７】
ここで、「粒子投影面積」とは２値化されたトナー像の面積であり、「粒子投影像の周囲長」は、該トナー像のエッジ点を結んで得られる輪郭線の長さと定義する。
【００３８】
本発明に於ける円形度はトナーの凹凸の度合いを示す指標であり、トナーが完全な球形の場合に１．００を示し、表面形状が複雑になる程、円形度は小さな値となる。
【００３９】
本発明において、トナーの個数基準の粒径頻度分布の平均値を意味する円相当個数平均径Ｄ１は、粒度分布の分割点ｉでの粒径（中心値）をｄｉ、頻度をｆｉとすると次式から算出される。
【００４０】
【外２】

【００４１】
また、円形度頻度分布の平均値を意味する平均円形度ｃは粒度分布の分割点ｉでの円形度（中心値）をｃｉ、頻度をｆｃｉとすると次式から算出される。
【００４２】
【外３】

【００４３】
具体的な測定方法としては、容器中に予め不純固形物などを除去したイオン交換水１０ｍｌを用意し、その中に分散剤として界面活性剤、好ましくはアルキルベンゼンスルホン酸塩を加えた後、さらに測定試料を０．０２ｇ加え、均一に分散させる。分散させる手段としては、超音波分散ＵＨ−５０型（エスエムテー社製）に振動子として５φのチタン合金チップを装着したものを用い、５分間分散処理を行い、測定用の分散液とする。その際、該分散液の温度が４０℃以上とならない様に適宜冷却する。
【００４４】
トナーの形状測定には、前記フロー式粒子像測定装置を用い、測定時のトナー濃度が３０００〜１万個／μｌとなる様に該分散液濃度を再調整し、トナー粒子を１０００個以上計測する。計測後、このデータを用いて、トナーの円相当径と円形度の２元次頻度分布図（スキャッタグラム）を求める。
【００４５】
本発明のトナーに用いられる結着樹脂としては、一般的に用いられているスチレン−（メタ）アクリル共重合体，ポリエステル樹脂，エポキシ樹脂，スチレン−ブタジエン共重合体が挙げられる。重合法により直接トナー粒子を得る方法においては、それらを形成するための単量体が用いられる。具体的にはスチレン；ｏ（ｍ−，ｐ−）−メチルスチレン，ｍ（ｐ−）−エチルスチレンの如きスチレン系単量体；（メタ）アクリル酸メチル，（メタ）アクリル酸エチル，（メタ）アクリル酸プロピル，（メタ）アクリル酸ブチル，（メタ）アクリル酸オクチル，（メタ）アクリル酸ドデシル，（メタ）アクリル酸ステアリル，（メタ）アクリル酸ベヘニル，（メタ）アクリル酸２−エチルヘキシル，（メタ）アクリル酸ジメチルアミノエチル，（メタ）アクリル酸ジエチルアミノエチルの如き（メタ）アクリル酸エステル系単量体；ブタジエン，イソプレン，シクロヘキセン，（メタ）アクリロニトリル，アクリル酸アミドの如きエン系単量体が好ましく用いられる。これらは、単独、または、一般的には出版物ポリマーハンドブック第２版ＩＩＩ−Ｐ１３９〜１９２（Ｊｏｈｎ Ｗｉｌｅｙ＆Ｓｏｎｓ社製）に記載の理論ガラス転移温度（Ｔｇ）が、４０〜５０℃を示すように単量体を適宜混合して用いられる。理論ガラス転移温度が４０℃未満の場合にはトナーの保存安定性や耐久安定性の面から問題が生じやすく、一方７５℃を超える場合はトナーの定着点の上昇をもたらす。特にフルカラー画像を形成するためのカラートナーの場合においては各色トナーの定着時の混色性が低下し、色再現性に乏しく、さらにＯＨＰ画像の透明性が低下するため好ましくない。
【００４６】
結着樹脂の分子量は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により測定される。コア−シェル構造を有するトナーの場合、具体的なＧＰＣの測定方法としては、予めトナーをソックスレー抽出器を用いトルエン溶剤で２０時間抽出を行った後、ロータリーエバポレーターでトルエンを留去せしめて抽出物を得、さらに低軟化点物質は溶解するが外殻樹脂は溶解しない有機溶剤（例えばクロロホルム等）を抽出物に加え十分洗浄を行った後、残留物をテトラヒドロフラン（ＴＨＦ）に溶解した溶液をポア径が０．３μｍの耐溶剤性メンブランフィルターでろ過したサンプル（ＴＨＦ溶液）をウォーターズ社製１５０Ｃを用いて測定する。カラム構成は昭和電工製Ａ−８０１、８０２、８０３、８０４、８０５、８０６、８０７を連結し標準ポリスチレン樹脂の検量線を用い分子量分布を測定し得る。本発明に係る結着樹脂の主たるピーク分子量は５０００〜１００万、重量平均分子量（Ｍｗ）と数平均分子量（Ｍｎ）の比（Ｍｗ／Ｍｎ）が、２〜１００を示すものが本発明には好ましい。
【００４７】
本発明に用いられる着色剤は、以下に示すイエロー着色剤，マゼンタ着色剤及びシアン着色剤が挙げられ、黒色着色剤としてカーボンブラック，磁性体または以下に示すイエロー着色剤／マゼンタ着色剤／シアン着色剤を混合して黒色に調色されたものが利用される。
【００４８】
イエロー着色剤としては、縮合アゾ化合物，イソインドリノン化合物，アンスラキノン化合物，アゾ金属錯体，メチン化合物，アリルアミド化合物に代表される化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントイエロー１２、１３、１４、１５、１７、６２、７４、８３、９３、９４、９５、１０９、１１０、１１１、１２８、１２９、１４７、１６８、１８０等が好適に用いられる。
【００４９】
マゼンタ着色剤としては、縮合アゾ化合物，ジケトピロロピロール化合物，アンスラキノン，キナクリドン化合物，塩基染料レーキウ化合物，ナフトール化合物，ベンズイミダゾロン化合物，チオインジゴ化合物，ペリレン化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントレッド２、３、５、６、７、２３、４８；２、４８；３、４８；４、５７；１、８１；１、１４４、１４６、１６６、１６９、１７７、１８４、１８５、２０２、２０６、２２０、２２１、２５４が特に好ましい。
【００５０】
シアン着色剤としては、銅フタロシアニン化合物及びその誘導体，アンスラキノン化合物，塩基染料レーキ化合物等が利用できる。具体的には、Ｃ．Ｉ．ピグメントブルー１、７、１５、１５；１，１５；２，１５；３，１５；４，６０，６２，６６等が特に好適に利用できる。
【００５１】
これらの着色剤は、単独又は混合しさらには固溶体の状態で用いることができる。着色剤は、色相，彩度，明度，耐候性，ＯＨＰ透明性，トナー粒子中への分散性の点から選択される。該着色剤の添加量は、樹脂成分１００重量部に対し１〜２０重量部使用するのが好ましい。
【００５２】
黒色着色剤として磁性体を用いた場合には、他の着色剤と異なり、樹脂１００重量部に対し４０〜１５０重量部使用するのが好ましい。
【００５３】
本発明に係るワックス成分としては、パラフィンワックス、マイクロクリスタリンワックス、ペトロラクタム等の石油系ワックス及びその誘導体、モンタンワックス及びその誘導体、フィシャートロプシュ法による炭化水素ワックス及びその誘導体、ポリエチレンに代表されるポリオレフィンワックス及びその誘導体、カルナバワックス、キャンデリラワックス等、天然ワックス及びそれらの誘導体等で、誘導体には酸化物や、ビニルモノマーとのブロック共重合物、グラフト変性物も含み、又、高級脂肪族アルコール等のアルコール；ステアリン酸、パルミチン酸等の脂肪酸或いはその化合物；酸アミド、エステル、ケトン、硬化ヒマシ油及びその誘導体、植物ワックス、動物ワックス等、スチレンモノマーへの溶解温度が４０〜８０℃のものであればどこでも用いることが可能である。
【００５４】
これらの中でもポリオレフィン、フィッシャートロプシュ法による炭化水素ワックス、石油系ワックス、高級アルコール、もしくは、高級エステルである場合、現像性や転写性の改善効果がさらに高くなる。
【００５５】
上述したワックス成分は、結着樹脂１００重量部に対して１〜３０重量部使用するのが好ましい。
【００５６】
又、該ワックス成分には、トナーの帯電性に影響を与えない範囲で酸化防止剤が添加されていても良い。
【００５７】
本発明に係るワックス成分は、透過電子顕微鏡（ＴＥＭ）を用いたトナーの断層面観察において、該ワックス成分が結着樹脂と相溶しない状態で、実施的に球状及び／又は紡錘形で島状に分散されている。
【００５８】
本発明において、上記の如きワックス成分の分散状態は以下の様に定義される。すなわち、前述のフロー式粒子像測定装置で測定されるトナーの重量基準の粒径頻度分布の平均値を意味する円相当重量平均径Ｄ４（μｍ）に対し、Ｄ４×０．９以上であり、Ｄ４×１．１以下の長径を有するトナー粒子の断層面を１０ケ所選び出す。そして、各トナー粒子の断層面の長径Ｒと、長径Ｒであるトナー粒子の断層面中に存在しているワックス成分に起因する相分離構造の中で、最も大きい長径ｒを計測し、ｒ／Ｒの平均値を求める。ｒ／Ｒの平均値が０．５≦ｒ／Ｒの平均値≦０．９５を満たす分散状態にある場合、ワックス成分が結着樹脂と相溶しない状態で、実質的に球形及び／又は紡錘形で島状の分散状態を有しているものとする。
【００５９】
ワックス成分を上記の如く分散させ、トナー中に内包化させることによりトナーの劣化や画像形成装置の汚染等を防止することが出来る。特にｒ／Ｒの平均値が０．２５≦ｒ／Ｒ≦０．９０を満たす分散状態にある場合、良好な帯電性が維持され、ドット再現に優れたトナー画像を長期にわたって形成し得ることが可能となるので好ましい。又、加熱時にはワックス成分が効率良く作用する為、低温定着性と耐オフセット性を満足なものとする。さらに、トナーの形状分布を所望のものとする際、後述するような回転ブレードを用いる衝撃式粉体処理装置によりトナー粒子の形状や表面に処理を施してもトナーの性能低下や処理装置へのトナー融着を未然に防止することが可能であり、トナーの形状分布を精密に制御することによりトナーに望ましい特性を与えることが出来る。
【００６０】
本発明においてトナー粒子の断層面を観察する具体的方法としては、常温硬化性のエポキシ樹脂中にトナー粒子を十分に分散させた後、４０℃の雰囲気温度中で２日間硬化させ、得られた硬化物を四三酸化ルテニウム、必要により四三酸化オスミウムを併用し染色を施した後、ダイヤモンド歯を備えたミクロトームを用い薄片状のサンプルを切り出し透過電子顕微鏡（ＴＥＭ）を用いトナー粒子の断層形態を測定する。本発明においては、用いるワックス成分と外殻を構成する樹脂との若干の結晶化度の違いを利用して材料間のコントラストを付けるため四三酸化ルテニウム染色法を用いることが好ましい。代表的な一例を図７に示す。後記の実施例で得られたトナー粒子は、ワックス成分が外殻樹脂で内包化されていることが観測された。
【００６１】
本発明に用いられる荷電制御剤としては、公知のものが利用できるが帯電スピードが速く、且つ、一定の帯電量を安定して維持できる荷電制御剤が好ましい。さらに、トナー粒子を直接重合法を用いる場合には、重合阻害性が無く水系分散媒体への可溶化物の無い荷電制御剤が特に好ましい。具体的化合物としては、ネガ系荷電制御剤としてサリチル酸、ナフトエ酸、ダイカルボン酸の如き芳香族カルボン酸の金属化合物；スルホン酸又はカルボン酸基を側鎖に持つ高分子型化合物；ホウ素化合物；尿素化合物；ケイ素化合物；カリークスアレーン等が挙げられる。ポジ系荷電制御剤として、四級アンモニウム塩；該四級アンモニウム塩を側鎖に有する高分子型化合物；グアニジン化合物；イミダゾール化合物等が挙げられる。該荷電制御剤は樹脂１００重量部に対し０．５〜１０重量部使用することが好ましい。しかしながら、本発明において荷電制御剤の添加は必須ではなく、二成分現像方法を用いた場合においては、キャリヤーとの摩擦帯電を利用し、非磁性一成分ブレードコーティング現像方法を用いた場合においては、ブレード部材やスリーブ部材との摩擦帯電を積極的に利用することでトナー粒子中に必ずしも荷電制御剤を含む必要はない。
【００６２】
本発明のトナーに無機微粉体を添加することは、現像性、転写性、帯電安定性、流動性、及び、耐久性向上の為に好ましい実施形態である。該無機微粉体としては公知のものが使用可能であるが、特にシリカ，アルミナ，チタニアあるいはその複酸化物の中から選ばれることが好ましい。さらには、シリカであることがより好ましい。例えば、かかるシリカは硅素ハロゲン化物やアルコキシドの蒸気相酸化により生成されたいわゆる乾式法又はヒュームドシリカと称される乾式シリカ及びアルコキシド，水ガラス等から製造されるいわゆる湿式シリカの両者が使用可能であるが、表面及びシリカ微粉体の内部にあるシラノール基が少なく、またＮａ_２ Ｏ，ＳＯ_３ ^２−等の製造残滓の少ない乾式シリカの方が好ましい。また乾式シリカにおいては、製造工程において例えば、塩化アルミニウム，塩化チタン等他の金属ハロゲン化合物を硅素ハロゲン化合物と共に用いることによって、シリカと他の金属酸化物の複合微粉体を得ることも可能でありそれらも包含する。
【００６３】
本発明に用いられる無機微粉体はＢＥＴ法で測定した窒素吸着による比表面積が３０ｍ^２ ／ｇ以上、特に５０〜４００ｍ^２ ／ｇの範囲のものが良好な結果を与え、トナー１００質量部に対してシリカ微粉体０．１〜８質量部、好ましくは０．５〜５質量部、さらに好ましくは１．０を超えて３．０質量部まで使用するのが特に良い。
【００６４】
また、本発明に用いられる無機微粉体は、必要に応じ、疎水化，帯電性制御等の目的でシリコーンワニス，各種変性シリコーンワニス，シリコーンオイル，各種変性シリコーンオイル，シランカップリング剤，官能基を有するシランカップリング剤，その他有機硅素化合物，有機チタン化合物等の処理剤で、あるいは、種々の処理剤で併用して処理されていることも可能であり好ましい。
【００６５】
比表面積はＢＥＴ法に従って、比表面積測定装置オートソープ１（湯浅アイオニクス社製）を用いて試料表面に窒素ガスを吸着させ、ＢＥＴ多点法を用いて比表面積を算出した。
【００６６】
高い帯電量を維持し、低消費量及び高転写率を達成するためには、無機微粉体は少なくともシリコーンオイルで処理されることがさらに好ましい。
【００６７】
本発明のトナーにおいては、実質的な悪影響を与えない範囲内でさらに他の添加剤、例えばテフロン粉末、ステアリン酸亜鉛粉末、ポリフッ化ビニリデン粉末の如き滑剤粉末；酸化セリウム粉末、炭化硅素粉末、チタン酸ストロンチウム粉末などの研磨剤；例えば酸化チタン粉末、酸化アルミニウム粉末などの流動性付与剤；ケーキング防止剤、あるいは例えばカーボンブラック粉末、酸化亜鉛粉末、酸化スズ粉末等の導電性付与剤、また、逆極性の有機微粒子及び無機微粒子を現像性向上剤として少量用いることもできる。
【００６８】
本発明のトナーを製造する方法としては、樹脂、低軟化点物質からなる離型剤、着色剤、荷電制御剤等を加圧ニーダーやエクストルーダー又はメディア分散機を用い均一に分散せしめた後、機械的又はジェット気流下でターゲットに衝突させ、所望のトナー粒径に微粉砕化せしめた後、（必要により、トナー粒子の平滑化及び球形化の工程を付加）、さらに分級工程を経て粒度分布をシャープにせしめトナーにする粉砕法によるトナーの製造方法の他に、特公昭５６−１３９４５号公報等に記載のディスク又は多流体ノズルを用い溶融混合物を空気中に霧化し球状トナーを得る方法や、特公昭３６−１０２３１号公報、特開昭５９−５３８５６号公報、特開昭５９−６１８４２号公報に述べられている懸濁重合方法を用いて直接トナーを生成する方法や、単量体には可溶で得られる重合体が不溶な水系有機溶剤を用い直接トナーを生成する分散重合方法又は水溶性極性重合開始剤存在下で直接重合しトナーを生成するソープフリー重合法に代表される乳化重合方法等を用いトナーを製造することが可能である。
【００６９】
粉砕法を用いてトナーを製造する方法においては、トナーの形状を所望の円形度頻度分布の範囲に納めることが困難であり、溶融スプレー法においては、ある程度の円形度を得ることが出来るが、得られるトナーの粒度分布が広くなり易い傾向があると共に、トナーの表面状態をコントロールすることが困難である。他方、分散重合法においては、得られるトナーは極めてシャープな粒度分布を示すが、使用する材料の選択が狭いことや有機溶剤の利用が廃溶剤の処理や溶剤の引火性に関する観点から製造装置が複雑で煩雑化しやすい。ソープフリー重合に代表される乳化重合方法は、トナーの粒度分布が比較的揃うため有効であるが、使用した乳化剤や重合開始剤末端がトナー粒子表面に存在した時に環境特性を悪化させやすい。
【００７０】
本発明においては、トナーの円形度頻度分布のコントロールが可能であり、比較的容易に小粒径化トナーが得られる常圧下、又は、加圧下での乳化剤重合法又は懸濁重合方法を用い、予め得られた重合体にメディアを用い定形化したり、直接加圧衝突板に重合体を衝突せしめる方法や、さらには得られた重合体を水系中にて凍結せしめたり、塩折や反対表面電荷を有する粒子をｐＨ等の条件を考慮することで合体し、凝集、合一せしめる凝集方法が特に好ましい。さらに、一旦得られた重合粒子にさらに単量体を吸着せしめた後、重合開始剤を用い重合せしめるシード重合方法も本発明に好適に利用することができる。
【００７１】
トナーの製造方法として直接重合方法を利用する場合、トナーの円形度頻度分布や粒度分布の制御は、難水溶性の無機塩や保護コロイド作用をする分散剤の種類や添加量を変える方法や機械的装置条件（例えばローターの周速、バス回数、撹拌羽根形状等の撹拌条件や容器形状）又は、水溶液中での固形分濃度等を制御することにより所定のトナー粒子を得ることができる。
【００７２】
直接重合法によりトナーを製造する際、用いられる重合開始剤として例えば、２，２′−アゾビス−（２，４−ジメチルバレロニトリル）、２，２′−アゾビスイソブチロニトリル、１，１′−アゾビス（シクロヘキサン−１−カルボニトリル）、２，２′−アゾビス−４−メトキシ−２，４−ジメチルバレロニトリル、アゾビスイソブチロニトリルの如きアゾ系又はジアゾ系重合開始剤；ベンゾイルペルオキシド、メチルエチルケトンペルオキシド、ジイソプロピルペルオキシカーボネート、クメンヒドロペルオキシド、２，４−ジクロロベンゾイルペルオキシド、ラウロイルペルオキシドの如き過酸化物系重合開始剤が用いられる。該重合開始剤の使用量は、目的とする重合度により変化するが一般的には重合性単量体に対し０．５〜２０重量％用いられる。重合開始剤の種類は、重合法により若干異なるが、十時間半減期温度を参考に、単独又は混合して使用される。
【００７３】
重合度を制御するため公知の架橋剤、連鎖移動剤、重合禁止剤等をさらに添加して用いても良い。
【００７４】
トナーの製法として分散安定剤を用いた懸濁重合法を利用する場合、用いる分散安定剤としては、無機化合物として、リン酸三カルシウム、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、水酸化カルシウム、水酸化マグネシウム、水酸化アルミニウム、メタケイ酸カルシウム、硫酸カルシウム、硫酸バリウム、ベントナイト、シリカ、アルミナ等が挙げられる。有機化合物としては、ポリビニルアルコール、ゼラチン、メチルセルロース、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、デンプン等が挙げられる。これらを水相に分散させて使用できる。これら分散安定剤は、重合性単量体１００重量部に対して０．２〜２０重量部を使用することが好ましい。
【００７５】
分散安定剤として、無機化合物を用いる場合、市販のものをそのまま用いても良いが、細かい粒子を得るために、分散媒体中にて該無機化合物の微粒子を生成しても良い。例えば、リン酸三カルシウムの場合、高速撹拌下において、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。
【００７６】
これら分散安定剤の微細な分散の為に、０．００１〜０．１重量部の界面活性剤を併用してもよい。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、例えば、ドデドシルベンゼン硫酸ナトリウム、テトラデシル硫酸ナトリウム、ペンタデシル硫酸ナトリウム、オクチル硫酸ナトリウム、オレイン酸ナトリウム、ラウリル酸ナトリウム、ステアリン酸カリウム、オレイン酸カルシウム等が挙げられる。
【００７７】
本発明で使用するトナーの製造方法として直接重合法を用いる場合においては、以下の如き製造方法が可能である。
【００７８】
重合性単量体中に、低軟化点物質からなるワックス成分、着色剤、荷電制御剤、重合開始剤その他の添加剤を加え、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た単量体組成物を、分散安定剤を含有する水相中に通常の撹拌機またはホモミキサー、ホモジナイザー等により分散せしめる。好ましくは単量体組成物の液滴が所望のトナー粒子のサイズを有するように撹拌速度、撹拌時間を調整し、造粒する。その後は分散安定剤の作用により、粒子状態が維持され、且つ粒子の沈降が防止される程度の撹拌を行えば良い。重合温度４０℃以上、一般的には５０〜９０℃の温度に設定して重合を行うのが良い。重合反応後半に昇温しても良く、さらに、本発明に於ける画像形成方法における耐久性向上の目的で、未反応の重合性単量体、副生成物等を除去するために反応後半、又は、反応終了後に一部水系媒体を反応系から留去しても良い。反応終了後、生成したトナー粒子を洗浄・濾過により回収し、乾燥する。懸濁重合法においては、通常単量体組成物１００重量部に対して水３００〜３０００重量部を分散媒体として使用するのが好ましい。
【００７９】
一方、トナーの形状分布を所望のものとする為に、回転ブレードを用いる衝撃式粉体処理装置によりトナー粒子の形状や表面に処理を加えることは本発明の好ましい実施形態の一つである。
【００８０】
回転ブレードを用いる衝撃式粉体処理装置としてはＹ．Ｔａｋａｙａｍａ，Ｙ．Ｋｉｋｕｃｈｉ ａｎｄ Ｋ．Ｏｎｏ：ＺＡＩＲＹＯ ＧＩＪＵＴＳＵ Ｖｏｌ．８，Ｎｏ．８，１０，（１９９０）に記載されている粉体処理装置や奈良機械社製ハイブリダイゼーションシステムやターボ工業社製衝撃式微粉砕機等の公知の製造装置を用いることが出来るが、トナー粒子に均一な処理を施し、所望の形状分布に精密にコントロールし、尚且つ、高い生産性を達成する為には図１１〜１３に示した粉体処理装置を用いることが好ましい。
【００８１】
本発明に好適な回転ブレードを用いた衝撃式粉体処理装置について、図面を参照しながら具体的に説明する。
【００８２】
図１１は、本発明に好適な粉体処理装置Ａを組み込んだ粉体形状処理装置システムの一例であり、図１２は該粉体処理装置Ａの部分的断面図、図１３は回転ロータを４段有する回転駆動軸の斜視図である。
【００８３】
図１２に示す粉体処理装置Ａは、円筒状ケーシング５１内には第１〜第４の円筒状処理室７９ａ〜７９ｄが連結して設けられており、それぞれ１０枚のブレードを有する回転ロータ５２ａ〜５２ｄが回転駆動軸５３に固定された状態で内包されている。回転駆動軸５３は軸受け６１と６２により支持され、下方の端部にあるプーリー５４に掛けられたベルトによって電動モーター８４の回転が伝達され、矢印の方向に高速回転する。
【００８４】
図１１に示す定量供給装置６６内のトナー粒子は、振動フィーダ６５を経由し、ホッパー８２と粉体供給管８１を通って第１の円筒状処理室７９ａの前方壁８３の中央部に設けられている粉体供給口８０から空気と共に第１の円筒状処理室７９ａに吸引プロア７４の吸引力により導入される。第１の円筒状処理室７９ａに導入されたトナー粒子は、１０枚のブレードを有する回転ロータ５２ａの回転に伴って発生する中心方向から側壁５７ａへの気流によって第１の円筒状処理室の側壁５７ａに衝突し、第１の円筒状処理室７９ａの空間内を対流しながら表面処理を受け、逐次、側壁５７ａとブレード５９ａとの間隙を通り、回転ロータ５２ａの背面と第１の後方壁５８ａ（ガイド板又は第２の前方壁ともいう）との間隙を通り、第１の後方壁５８ａの中央部に設けられた第１の粉体排出口６０ａから排出される。処理装置Ａにおいて、第１の粉体排出口６０ａは第２の円筒状処理室７９ｂの粉体供給口を兼ねており、トナー粒子は第１の粉体排出口６０ａを経由して第２の円筒状処理室７９ｂの中央部に導入される。第２の円筒状処理室７９ｂにおいて、第１の円筒状処理室７９ａで表面処理されたトナー粒子は、第１の円筒状処理室７９ａと同様にして、１０枚のブレードを有する回転ロータ５２ｂの回転によりさらに表面処理される。さらに、第２の円筒状処理室７９ｂで表面処理されたトナー粒子は、引き続き第３の円筒状処理室７９ｃと第４の円筒状処理室７９ｄで表面処理される。
【００８５】
第４の円筒状処理室７９ｄで表面処理されたトナー粒子は、ガイド板５８ｄの中央部に設けられた第４の粉体排出口６０ｄを通り、円筒状ケーシング５１の接線方向に設けられた排出管６３の排出口６３ａを経由し、連結管６７を通って、サイクロン７０に貯留される。サイクロン７０に貯留された表面処理されたトナー粒子は、バルブ７１から適宜取り出される。
【００８６】
トナーの形状分布は、前記粉体処理装置の円筒状処理室の形状や回転ロータに固定されたブレードの形状や枚数や固定位置、回転ロータの回転数の他に円筒状処理室内でのトナー粒子の滞留時間、粒子濃度、処理時の雰囲気温度等により適宜調整することが可能である。
【００８７】
次に本発明のトナーが適用される画像形成方法を添付図面を参照しながら以下に説明する。
【００８８】
図１に示す装置システムにおいて、現像器４−１、４−２、４−３、４−４に、それぞれシアントナーを有する現像剤、マゼンタトナーを有する現像剤、イエロートナーを有する現像剤及びブラックトナーを有する現像剤が導入され、磁気ブラシ現像方式又は非磁性一成分方式等によって静電潜像担持体（例えば感光体ドラム）１に形成された静電荷像を現像し、各色トナー像が感光体ドラム１上に形成される。
【００８９】
本発明のトナーは、磁性キャリアと混合し、例えば図２に示すような現像手段を用い現像を行うことができる。具体的には交番電界を印加しつつ、磁気ブラシが感光体ドラム１３に接触している状態で現像を行うことが好ましい。現像剤担持体（現像スリーブ）１１と感光体ドラム１３の距離（Ｓ−Ｄ間距離）Ｂは１００〜１０００μｍであることがキャリア付着防止及びドット再現性の向上において良好である。１００μｍより狭いと現像剤の供給が不十分になりやすく、画像濃度が低くなり、１０００μｍを超えると磁石Ｓ１からの磁力線が広がり磁気ブラシの密度が低くなり、ドット再現性に劣ったり、キャリアを拘束する力が弱まりキャリア付着が生じやすくなる。
【００９０】
交番電界のピーク間の電圧（Ｖｐｐ）は５００〜５０００Ｖが好ましく、周波数（ｆ）は５００〜１００００Ｈｚ、好ましくは５００〜３０００Ｈｚであり、それぞれプロセスに適宜選択して用いることができる。この場合、波形としては三角波、矩形波、正弦波、あるいはＤｕｔｙ比を変えた波形等種々選択して用いることができる。印加電圧が、５００Ｖより低いと十分な画像濃度が得られにくく、また非画像部のカブリトナーを良好に回収することができない場合がある。５０００Ｖを超える場合には磁気ブラシを介して、静電像を乱してしまい、画質低下を招く場合がある。
【００９１】
良好に帯電したトナーを有する二成分系現像剤を使用することで、カブリ取り電圧（Ｖｂａｃｋ）を低くすることができ、感光体の一次帯電を低めることができるために感光体寿命を長寿命化できる。Ｖｂａｃｋは、現像システムにもよるが１５０Ｖ以下、より好ましくは１００Ｖ以下が良い。
【００９２】
コントラスト電位としては、十分画像濃度がでるように２００Ｖ〜５００Ｖが好ましく用いられる。
【００９３】
周波数が５００Ｈｚより低いとプロセススピードにも関係するが、キャリアへの電荷注入が起こるためにキャリア付着、あるいは潜像を乱すことで画質を低下させる場合がある。１００００Ｈｚを超えると電界に対してトナーが追随できず画質低下を招きやすい。
【００９４】
十分な画像濃度を出し、ドット再現性に優れ、かつキャリア付着のない現像を行うために現像スリーブ１１上の磁気ブラシの感光体ドラム１３との接触幅（現像ニップＣ）を好ましくは３〜８ｍｍにすることである。現像ニップＣが３ｍｍより狭いと十分な画像濃度とドット再現性を良好に満足することが困難であり、８ｍｍより広いと、現像剤のパッキングが起き機械の動作を止めてしまったり、またキャリア付着を十分に抑えることが困難になる。現像ニップの調整方法としては、現像剤規制部材１８と現像スリーブ１１との距離Ａを調整したり、現像スリーブ１１と感光体ドラム１３との距離Ｂを調整することでニップ幅を適宜調整する。
【００９５】
特にハーフトーンを重視するようなフルカラー画像の出力において、マゼンタ用、シアン用、及びイエロー用の３個以上の現像器が使用され、本発明の現像剤及び現像方法を用い、特にデジタル潜像を形成した現像システムと組み合わせることで、磁気ブラシの影響がなく、映像を乱さないためにドット潜像に対して忠実に現像することが可能となる。転写工程においても本発明トナーを用いることで高転写率が達成でき、したがって、ハーフトーン部、ベタ部共に高画質を達成できる。
【００９６】
さらに初期の高画質化と併せて、本発明のトナーを用いることで多数枚の複写においても画質低下のない本発明の効果が十分に発揮できる。
【００９７】
本発明のトナーは一成分現像にも好適に用いることが出来る。静電潜像担持体上に形成された静電像を現像する装置の一例を示すが必ずしもこれに限定されるものではない。
【００９８】
図３において、２５は静電潜像担持体（感光体ドラム）であり、潜像形成は電子写真プロセス手段又は静電記録手段により成される。２４はトナー担持体（現像スリーブ）であり、アルミニウムあるいはステンレス等からなる非磁性スリーブからなる。
【００９９】
現像スリーブ２４の略右半周面はトナー容器２１内のトナー溜りに常時接触していて、その現像スリーブ面近傍のトナーが現像スリーブ面にスリーブ内の磁気発生手段の磁力で及び／又は静電気力による付着保持される。
【０１００】
本発明では、トナー担持体の表面粗度Ｒａ（μｍ）を１．５以下となるように設定する。好ましくは１．０以下である。さらに好ましくは０．５以下である。
【０１０１】
該表面粗度Ｒａを１．５以下とすることでトナー担持体の有するトナー粒子の搬送能力を抑制し、該トナー担持体上のトナー層を薄層化すると共に、該トナー担持体とトナーの接触回数が多くなる為、該トナーの帯電性も改善されるので相乗的に画質が向上する。
【０１０２】
該トナー担持体の表面粗度Ｒａが１．５を超えると、該トナー担持体上のトナー層の薄層化が困難となるばかりか、トナーの帯電性が改善されないので画質の向上は望めない。
【０１０３】
本発明において、トナー担持体の表面粗度Ｒａは、ＪＩＳ表面粗さ「ＪＩＳＢ０６０１」に基づき、表面粗さ測定器（サーフコーダＳＥ−３０Ｈ、株式会社小坂研究所社製）を用いて測定される中心線平均粗さに相当する。具体的には、粗さ曲線からその中心線の方向に測定長さａとして２．５ｍｍの部分を抜き取り、この抜き取り部分の中心線をＸ軸、縦倍率の方向をＹ軸、粗さ曲線をｙ＝ｆ（ｘ）で表わした時、次式によって求められる値をマイクロメートル（μｍ）で表したものをいう。
【０１０４】
【外４】

【０１０５】
本発明に用いられるトナー担持体としては、例えばステンレス、アルミニウム等から成る円筒状、あるいはベルト状部材が好ましく用いられる。また必要に応じ表面を金属、樹脂等のコートをしても良く、樹脂や金属類、カーボンブラック、帯電制御剤等の微粒子を分散した樹脂をコートしても良い。
【０１０６】
本発明では、トナー担持体の表面移動速度を静電潜像担持体の表面移動速度に対し１．０５〜３．０倍となるように設定することで、該トナー担持体上のトナー層は適度な撹拌効果を受ける為、静電潜像の忠実再現が一層良好なものとなる。
【０１０７】
該トナー担持体の表面移動速度が、静電潜像担持体の表面移動速度に対し１．０５倍未満であると、該トナー層の受ける撹拌効果が不十分となり、良好な画像形成は望めない。また、ベタ黒画像等、広い面積にわたって多くのトナー量を必要とする画像を現像する場合、静電潜像へのトナー供給量が不足し画像濃度が薄くなる。逆に３．０を超える場合、上記の如きトナーの過剰な帯電によって引き起こされる種々の問題の他に、機械的ストレスによるトナーの劣化やトナー担持体へのトナー固着が発生、促進され、好ましくない。
【０１０８】
トナーＴはホッパー２１に貯蔵されており、供給部材２２によって現像スリーブ上へ供給される。供給部材として、多孔質弾性体、例えば軟質ポリウレタンフォーム等の発泡材により成る供給ローラが好ましく用いられる。該供給ローラを現像スリーブに対して、順または逆方向に０でない相対速度をもって回転させ、現像スリーブ上へのトナー供給と共に、スリーブ上の現像後のトナー（未現像トナー）のはぎ取りをも行う。この際、供給ローラの現像スリーブへの当接幅は、トナーの供給及びはぎ取りのバランスを考慮すると、２．０〜１０．０ｍｍが好ましく、４．０〜６．０ｍｍがより好ましい。その一方で、トナーに対する過大なストレスを余儀なくされ、トナーの劣化による凝集の増大、あるいは現像スリーブ、供給ローラ等へトナーの融着・固着が生じやすくなるが、本発明の現像法に用いられるトナーは、流動性、離型性に優れ、耐久安定性を有しているので、該供給部材を有する現像法においても好ましく用いられる。又、供給部材として、ナイロン、レーヨン等の樹脂繊維より成るブラシ部材を用いてもよい。尚、これらの供給部材は磁気拘束力を利用できない非磁性一成分トナーを使用する。一成分現像方法において極めて有効であるが、磁性一成分トナーを使用する一成分現像方法に使用してもよい。
【０１０９】
現像スリーブ上に供給されたトナーは規制部材によって薄層かつ均一に塗布される。トナー薄層化規制部材は、現像スリーブと一定の間隙をおいて配置される金属ブレード、磁性ブレード等のドクターブレードである。あるいは、ドクターブレードの代りに、金属、樹脂、セラミック等を用いた剛体ローラやスリーブを用いても良く、それらの内部に磁気発生手段を入れても良い。
【０１１０】
又、トナー薄層化の規制部材としてトナーを圧接塗布する為の弾性ブレードや弾性ローラの如き弾性体を用いても良い。例えば図３において、弾性ブレード２３はその上辺部側である基部を現像剤容器２１側に固定保持され、下辺部側をブレードの弾性に抗して現像スリーブ２４の順方向或いは逆方向にたわめ状態にしてブレード内面側（逆方向の場合には外面側）をスリーブ２４表面に適度の弾性押圧をもって当接させる。この様な装置によると、環境の変動に対しても安定で、緻密なトナー層が得られる。その理由は必ずしも明確ではないが、該弾性体によって現像スリーブ表面と強制的に摩擦される為トナーの環境変化による挙動の変化に関係なく常に同じ状態で帯電が行われる為と推測される。
【０１１１】
その一方で帯電が過剰になり易く、現像スリーブや弾性ブレード上にトナーが融着し易いが、本発明に用いられるトナーは離型性に優れると共に摩擦帯電性が安定しているので好ましく用いられる。
【０１１２】
該弾性体には所望の極性にトナーを帯電させるのに適した摩擦帯電系列の材質を選択することが好ましく、シリコーンゴム、ウレタンゴム、ＮＢＲの如きゴム弾性体；ポリエチレンテレフタレートの如き合成樹脂弾性体；ステンレス、銅、リン青銅の如き金属弾性体が使用できる。また、それらの複合体であっても良い。
【０１１３】
また、弾性体とトナー担持体に耐久性が要求される場合には、金属弾性体に樹脂やゴムをスリーブ当接部に当るように貼り合わせたり、コーティング塗布したものが好ましい。
【０１１４】
さらに、弾性体中に有機物や無機物を添加しても良く、溶融混合させても良いし、分散させても良い。例えば、金属酸化物、金属粉、セラミックス、炭素同素体、ウィスカー、無機繊維、染料、顔料、界面活性剤等を添加することにより、トナーの帯電性をコントロールできる。特に、弾性体がゴムや樹脂等の成型体の場合には、シリカ、アルミナ、チタニア、酸化錫、酸化ジルコニア、酸化亜鉛等の金属酸化物微粉末、カーボンブラック、一般にトナーに用いられる荷電制御剤等を含有させることも好ましい。
【０１１５】
またさらに、規制部材である現像ブレード、供給部材である供給ローラ、ブラシ部材に直流電場及び／又は交流電場を印加することによっても、トナーへのほぐし作用のため現像スリーブ上の規制部位においては、均一薄層塗布性、均一帯電性がより向上し、供給部位においては、トナーの供給／はぎ取りがよりスムーズになされ、十分な画像濃度の達成及び良質の画像を得ることができる。
【０１１６】
該弾性体とトナー担持体との当接圧力は、トナー担持体の母線方向の線圧として、０．１ｋｇ／ｍ以上、好ましくは０．３〜２５ｋｇ／ｍ、さらに好ましくは０．５〜１２ｋｇ／ｍが有効である。これによりトナーの凝集を効果的にほぐすことが可能となり、トナーの帯電量を瞬時に立ち上げることが可能になる。当接圧力が０．１ｋｇ／ｍより小さい場合、トナーの均一塗布が困難となり、トナーの帯電量分布がブロードになりカブリや飛散の原因となる。又当接圧力が２５ｋｇ／ｍを超えると、トナーに大きな圧力がかかり、トナーが劣化したり、トナーの凝集物が発生する等好ましくない。又トナー担持体を駆動させるために大きなトルクを要するため好ましくない。
【０１１７】
静電潜像担持体とトナー担持体との間隙αは、５０〜５００μｍに設定され、ドクターブレードとトナー担持体との間隙は、５０〜４００μｍに設定されることが好ましい。
【０１１８】
トナー担持体上のトナー層の層厚は、静電潜像担持体とトナー担持体との間隙αよりも薄いことが最も好ましいが、場合によりトナー層を構成する多数のトナーの穂のうち、一部は静電潜像担持体に接する程度にトナー層の層厚を規制してもよい。
【０１１９】
一方、トナー担持体には、バイアス電源２６により静電潜像担持体との間に交番電界を印加することによりトナー担持体から静電潜像担持体へのトナーの移動を容易にし、さらに良質の画像を得ることができる。交番電界のＶｐｐは１００Ｖ以上、好ましくは２００〜３０００Ｖ、さらに好ましくは３００〜２０００Ｖで用いるのが良い。また、ｆは５００〜５０００Ｈｚ、好ましくは１０００〜３０００Ｈｚ、さらに好ましくは１５００〜３０００Ｈｚで用いられるこの場合の波形は、矩形波、サイン波、のこぎり波、三角波等の波形が適用できる。又、正、逆の電圧、時間の異なる非対称交流バイアスも利用できる。又直流バイアスを重畳するのも好ましい。
【０１２０】
静電潜像担持体はａ−Ｓｅ、Ｃｄｓ、ＺｎＯ_２ 、ＯＰＣ、ａ−Ｓｉの様な光導電絶縁物質層を持つ感光ドラムもしくは感光ベルトである。
【０１２１】
静電潜像担持体としては、アモルファスシリコン感光層、又は有機系感光層を有する感光体が好ましく用いられる。
【０１２２】
有機感光層としては、感光層が電荷発生物質及び電荷輸送性能を有する物質を同一層に含有する、単一層型でもよく、又は、電荷輸送層を電荷発生層を成分とする機能分離型感光層であっても良い。導電性基体上に電荷発生層、次いで電荷輸送層の順で積層されている構造の積層型感光層は好ましい例の一つである。
【０１２３】
有機感光層の結着樹脂はポリカーボネート樹脂、ポリエステル樹脂、アクリル系樹脂が特に、転写性、クリーニング性が良く、クリーニング不良、感光体へのトナーの融着、外添剤のフィルミングが起こりにくい。
【０１２４】
帯電工程では、コロナ帯電器を用いる静電潜像担持体１とは非接触である方式と、ローラ等を用いる接触型の方式がありいずれのものも用いられる。効率的な均一帯電、シンプル化、低オゾン発生化のために図１に示す如く接触方式のものが好ましく用いられる。
【０１２５】
帯電ローラ２は、中心の芯金２ｂとその外周を形成した導電性弾性層２ａとを基本構成とするものである。帯電ローラ２は、静電潜像担持体１面に押圧力をもって圧接され、静電潜像担持体１の回転に伴い従動回転する。
【０１２６】
帯電ローラを用いた時の好ましいプロセス条件としては、ローラの当接圧が５〜５００ｇ／ｃｍで、直流電圧に交流電圧を重畳したものを用いた時には、交流電圧は０．５〜５ｋＶｐｐ、交流周波数は５０Ｈｚ〜５ｋＨｚ、直流電圧は±０．２〜±１．５ｋＶであり、直流電圧のみを用いた時には、直流電圧は±０．２〜±５ｋＶである。
【０１２７】
この他の帯電手段としては、帯電ブレードを用いる方法や、導電性ブラシを用いる方法がある。これらの接触帯電手段は、高電圧が不必要になったり、オゾンの発生が低減するといった効果がある。
【０１２８】
接触帯電手段としての帯電ローラ及び帯電ブレードの材質としては、導電性ゴムが好ましく、その表面に離型性被膜をもうけても良い。離型性被膜としては、ナイロン系樹脂、ＰＶＤＦ（ポリフッ化ビニリデン）ＰＶＤＣ（ポリ塩化ビニリデン）などが適用可能である。
【０１２９】
又、静電潜像担持体上のトナー像は、電圧（例えば、±０．１〜±５ｋＶ）が印加されている中間転写体５に転写される。静電潜像担持体表面は、クリーニングブレード８を有するクリーニング手段９でクリーニングされる。
【０１３０】
中間転写体５は、パイプ状の導電性芯金５ｂと、その外周面に形成した中抵抗の弾性体層５ａからなる。芯金５ｂは、プラスチックのパイプに導電性メッキをほどこしたものでも良い。
【０１３１】
中抵抗の弾性体層５ａは、シリコーンゴム、テフロンゴム、クロロプレンゴム、ウレタンゴム、ＥＰＤＭ（エチレンプロピレンジエン３元共重合体）等の弾性材料に、カーボンブラック、酸化亜鉛、酸化スズ、炭化ケイ素の如き導電性付与剤を配合分散して電気抵抗値（体積抵抗率）を１０^５ 〜１１^１１Ω／ｃｍの中抵抗に調整した、ソリッドあるいは発泡肉質の層である。
【０１３２】
中間転写体５は静電潜像体１に対して並行に軸受けさせて静電潜像担持体１の下面部に接触させて配設してあり、静電潜像担持体１と同じ周速度で接触部において同方向に回転する。
【０１３３】
静電潜像担持体１の面に形成担持された第１色のトナー像が、静電潜像担持体１と中間転写体５とが接する転写ニップ部を通過する過程で中間転写体５に対する印加転写バイアスで転写ニップ域に形成された電界によって、中間転写体５の外面に転写され、その後、第２色、第３色、第４色と順次に転写される。
【０１３４】
必要により、着脱自在なクリーニング手段１０により、転写材へのトナー像の転写後に、中間転写体５の表面がクリーニングされる。中間転写体上にトナー像がある場合、トナー像を乱さないようにクリーニング手段１０は、中間転写体表面から離される。
【０１３５】
中間転写体５に対して並行に軸受けさせて中間転写体５の下面部に接触させて転写手段が配設され、転写手段７は例えば転写ローラ又は転写ベルトであり、中間転写体５と同じ周速度で矢印の時計方向に回転する。転写手段７は直接中間転写体５と接触するように配設されていても良く、又ベルト等が中間転写体５と転写手段７との間に接触するように配置されても良い。
【０１３６】
転写ローラの場合、中心の芯金７ｂとその外周を形成した導電性弾性層７ａとを基本構成とするものである。
【０１３７】
中間転写体及び転写ローラとしては、一般的な材料を用いることが可能である。中間転写体の弾性層の体積固有抵抗値よりも転写ローラの弾性層の体積固有抵抗値をより小さく設定することで転写ローラへの印加電圧が軽減でき、転写材上に良好なトナー像を形成できると共に転写材の中間転写体への巻き付きを防止することができる。特に中間転写体の弾性層の体積固有抵抗値が転写ローラの弾性層の体積固有抵抗値より１０倍以上であることが特に好ましい。
【０１３８】
例えば、転写ローラ７の導電性弾性層７ｂはカーボン等の導電材を分散させたポリウレタン、エチレン−プロピレン−ジエン系三元共重合体（ＥＰＤＭ）等の体積抵抗１０^６ 〜１０^１０Ωｃｍ程度の弾性体でつくられている。芯金７ａには定電圧電源によりバイアスが印加されている。バイアス条件としては、±０．２〜±１０ｋＶが好ましい。
【０１３９】
本発明のトナーは、転写工程での転写効率が高く、転写残トナーが少ない上に、クリーニング性に優れているので、静電潜像担持体上にフィルミングを生じにくい。さらに、多数枚耐久試験を行っても従来のトナーよりも、本発明のトナーは外添剤のトナー粒子表面への埋没が少なく、トナー表面の劣化を生じにくいため、良好な画質を長期にわたって維持し得る。特に図４の如き静電潜像担持体や中間転写体上の転写残トナーをクリーニングブレードの如きクリーニング手段で除去し、回収された該転写残トナーを再度利用するいわゆるリユース機構を有する画像形成装置に好ましく用いられる。
【０１４０】
次いで転写材６上のトナー画像は加熱加圧定着手段によって定着される。加熱加圧定着手段としては、ハロゲンヒーター等の発熱体を内蔵した加熱ローラとこれと押圧力をもって圧接された弾性体の加圧ローラを基本構成とする熱ロール方式や、フィルムを介してヒーターにより加熱定着する方式（図５、図６）が挙げられるが、本発明のトナーは定着性と耐オフセット性に優れるので上記の如き加熱加圧定着手段と良好なマッチングを示す。
【０１４１】
【発明の実施の形態】
以下、具体的実施例によって本発明を説明するが、本発明はなんらこれらに限定されるものではない。
【０１４２】
（トナーの製造例、並びに、比較製造例）
本発明のトナーの製造例、並びに、比較製造例について述べる。
【０１４３】
トナーの製造例１
高速撹拌装置ＴＫ式ホモミキサー（特殊機化工業社製）を備えた２リットル用４つ口フラスコ中にイオン交換水６５０ｇと０．１ｍｏｌ／ｌ−Ｎａ_３ ＰＯ_４ 水溶液５００ｇを投入し、回転数を１２０００ｒｐｍに調整し、７０℃に加温せしめた。ここに１ｍｏｌ／ｌ−ＣａＣｌ_２ 水溶液７０重量部を徐々に添加し、微小な難水溶性分散安定剤Ｃａ_３ （ＰＯ_４ ）_２ を含む水系分散媒体を調製した。
【０１４４】
一方、分散質として、

【０１４５】
上記混合物をアトライター（三井金属社製）を用い３時間分散させた後、２，２′−アゾビス（２，４−ジメチルバレロニトリル）５重量部を添加し重合性単量体組成物を調製した。
【０１４６】
次に、前記水系分散媒体中に該重合性単量体組成物を投入し、内温７０℃のＮ_２ 雰囲気下で、高速撹拌器の回転数を１２０００ｒｐｍに維持しつつ、１５分間撹拌し、該重合性単量体組成物を造粒した。その後、撹拌器をプロペラ撹拌羽根に換え５０ｒｐｍで撹拌しながら同温度で１０時間保持して重合を完了した。
【０１４７】
重合終了後、懸濁液を冷却し、次いで希塩酸を添加し分散安定剤を除去せしめた。さらに水洗浄を数回繰り返し、乾燥を行った後、図１１に示した１０枚のブレードを有する回転ロータが４段設けられている粉体処理装置システムを用いて重合体粒子の表面処理を行った。この時、該粉体処理装置システムの回転ロータの回転数は７９００ｒｐｍ（最外縁部の周速：１００ｍ／ｓｅｃ）、重合体粒子の処理量は１０ｋｇ／ｈｒで、処理時の雰囲気温度を３５℃とした。
【０１４８】
得られた重合体粒子（Ａ）は、円相当個数平均径が４．９μｍであり、平均円形度が０．９８９で、円相当径が１０μｍを越える粗粒子の含有量は１．７個数％であり、該粗粒子の平均円形度は０．９６５で、ＧＰＣによるピーク分子量が１．６万、Ｍｗ／Ｍｎが３５を呈するものであった。
【０１４９】
上記重合体粒子（Ａ）１００重量部と疎水性オイル処理シリカ微粉体（ＢＥＴ；２００ｍ^２ ／ｇ）２重量部をヘンシェルミキサーで乾式混合して、本発明のトナー（Ａ）とした後、該トナー（Ａ）６重量部と樹脂コート磁性フェライトキャリア（平均粒径；４５μｍ）９４重量部とを混合して磁気ブラシ現像用二成分系現像剤（Ａ）を調製した。
【０１５０】
得られたトナー（Ａ）は、重合体粒子（Ａ）と同等の粒度分布と形状分布を保持していた。又、該トナー（Ａ）中のワックス成分の分散状態をＴＥＭで観察したところ、図７（ａ）の模式図の様に結着樹脂と相溶しない状態で実質的に球状を呈し分散していた。この時、ｒ／Ｒは０．６１であった。
【０１５１】
トナーの製造例２〜４
水系分散媒体の調製条件と粉体処理装置システムの回転ロータの回転数と重合体粒子の処理量、さらには、処理時の雰囲気温度を調整することにより重合体粒子の粒子径と形状をコントロールした以外は、前記のトナーの製造例１と同様にして重合体粒子（Ｂ）〜（Ｄ）を得た後、トナー（Ｂ）〜（Ｄ）、及び、現像剤（Ｂ）〜（Ｄ）を調製した。
【０１５２】
トナーの比較製造例１

【０１５３】
上記混合物を二軸エクストルーダーで溶融混練し、冷却した混練物をハンマーミルで粗粉砕し、粗粉砕物をジェットミルで微粉砕し、得られた微粉砕物と市販のリン酸カルシウム微粉体とをヘンシェルミキサーで混合後、得られた混合粉体を水が入っている容器へ投入し、さらにホモミキサーを用い水中に分散させ水温を徐々に昇温させ温度６０℃で２時間加熱処理せしめた。その後希塩酸を容器に添加し、微粉砕物粒子表面のリン酸カルシウムを十分溶解した。これを濾別後に洗浄、乾燥せしめ、次いで４００メッシュの篩いを通して凝集物を除いた後、分級して分級粉（ａ）とした。該分級粉（ａ）を用い前記実施例１と同様にして比較用トナー（ａ）及び、比較用現像剤（ａ）を調製した。
【０１５４】
尚、比較用トナー（ａ）中のワックス成分は、微分散状態で含有されていた。その際、ｒ／Ｒは０．０１以下であった。
【０１５５】
トナーの比較製造例２
微粉砕と前記粉体処理システムの条件を変えることにより分級粉の粒子径と形状をコントロールした以外は、前記のトナーの比較製造例１と同様にして分級粉（ｂ）を得た後、比較用トナー（ｂ）、及び比較用現像剤（ｂ）を調製した。
【０１５６】
トナーの製造例５
エステルワックスの代わりに変性ポリプロピレンワックス（融点＝１０５℃）を用いると共に造粒時の撹拌条件や粉体処理装置システムの処理条件を調整した以外は、前記のトナーの製造例１と同様にして重合体粒子（Ｅ）を得た後、トナー（Ｅ）、及び、現像剤（Ｅ）を調整した。
【０１５７】
トナーの比較製造例３
粉体処理装置システムを用いないことを除いては、前記のトナーの製造例５と同様にして重合体粒子（ｃ）を得た後、比較用トナー（ｃ）、及び、比較用現像剤（ｃ）を調整した。
【０１５８】
上記で得られたトナー（Ａ）〜（Ｅ）、及び、比較用トナー（ａ）〜（ｃ）の諸性状を表１に示す。
【０１５９】
【表１】

【０１６０】
（実施例、参考例、並びに、比較例）
実施例１〜２、参考例１〜３、並びに、比較例１〜３
本実施例に用いた画像形成装置について説明する。図１と図２は、本実施例に適用される画像形成装置の断面の概略的説明図と二成分現像剤用の現像装置の要部の拡大横断図である。
【０１６１】
感光体ドラム１は、基材１ａ上に有機光半導体を有する感光層１ｂを有し、矢印方向に回転し、対抗し接触回転する帯電ローラ２（導電性弾性層２ａ、芯金２ｂ）により感光体ドラム１上に約−６００Ｖの表面電位に帯電させる。露光３は、ポリゴンミラーにより感光体上にデジタル画像情報に応じてオン−オフさせることで露光部電位が−１００Ｖ、暗部電位が−６００Ｖの静電荷像が形成される。フルカラー画像を形成する場合は、複数の現像器４−１、４−２、４−３、４−４を用いイエロートナー、マゼンタトナー、シアントナーまたは、ブラックトナーを感光体１上に反転現像方法を用いトナー像を得る。該トナー像は、中間転写体５（弾性層５ａ、支持体としての芯金５ｂ）上に転写され中間転写体５上に四色の色重ね顕色像が形成される。感光体１上の転写残トナーはクリーナー部材８により、残トナー容器９中に回収される。
【０１６２】
中間転写体５は、パイプ状の芯金５ｂ上にカーボンブラックの導電付与部材をニトリル−ブタジエンラバー（ＮＢＲ）中に十分分散させた弾性層５ｂをコーティングした。該コート層５ｂの硬度は、「ＪＩＳ Ｋ−６３０１」に準拠し３０度で且つ体積固有抵抗値は、１０^９ Ω・ｃｍであった。感光体１から中間転写体５への転写に必要な転写電流は約５μＡであり、これは電源より＋５００Ｖを芯金５ｂ上に付与することで得られた。
【０１６３】
転写ローラ７の外径２０ｍｍで直径１０ｍｍの芯金７ｂ上にカーボンの導電性付与部材をエチレン−プロピレン−ジエン系三元共重合体（ＥＰＤＭ）の発泡体中に十分分散させたものをコーティングすることにより生成した弾性層７ａを有し、弾性層７ａの体積固有抵抗値は、１０^６ Ω・ｃｍで、「ＪＩＳ Ｋ−６３０１」の基準の硬度は３５度の値を示すものを用いた。転写ローラには電圧を印加して１５μＡの転写電流を流した。
【０１６４】
加熱定着装置Ｈにはオイル塗布機能のない熱ロール方式の定着装置を用いた。この時上部ローラ、下部ローラ共にフッ素系樹脂の表面層を有するものを使用し、ローラの直径は６０ｍｍであった。また、定着温度は１６０℃、ニップ幅７ｍｍに設定した。
【０１６５】
以上の設定条件で、単色での連続モード（現像器を休止させることなくトナーの消費を促進させるモード）を使用して、毎分１２枚（Ａ４サイズ）のプリントアウト速度で、常温常湿（２５℃／６０％ＲＨ）環境下において１０００枚のプリントアウト試験を行い、さらにその後、高温高湿（３０℃／８０％ＲＨ）環境下において、９０００枚のプリントアウト試験を行った。尚、プリントアウト試験中、トナー（Ａ）〜（Ｅ）及び比較用現像剤（ａ）〜（ｃ）は逐次補給した。得られたプリントアウト画像及びプリントアウト試験終了後の画像形成装置を観察し、後述の項目について評価した。
【０１６６】
以上の評価結果を表２に示す。
【０１６７】
【表２】

【０１６８】
実施例３、並びに、比較例４
本実施例では市販のレーザービームプリンターＬＢＰ−ＥＸ（キヤノン社製）にリユース機構を取り付け改造し、再設定して用いた。即ち、図４において、感光体ドラム４０上の未転写トナーを該感光体ドラムに当接しているクリーナー４１の弾性ブレード４２によりかき落とした後、クリーナーローラによってクリーナー内部へ送り、さらにクリーナースクリュー４３を経て、搬送スクリューを設けた供給用パイプ４４によってホッパー４５を介して現像器４６に戻し、再度、回収トナーを利用するシステムを取り付け、一次帯電ローラ４７としてナイロン樹脂で被覆された導電性カーボンを分散したゴムローラ（直径１２ｍｍ、当接圧５０ｇ／ｃｍ）を使用し、静電潜像担持体にレーザー露光（６００ｄｐｉ）により暗部電位Ｖ_Ｄ＝−７００Ｖ、明部電位Ｖ_Ｌ＝−２００Ｖを形成した。トナー担持体として表面にカーボンブラックを分散した樹脂をコートした表面粗度Ｒａが１．１を呈する現像スリーブ４８を感光体ドラム面の移動速度に対して１．１倍となる様に設定し、次いで、感光体ドラムと該現像スリーブとの間隙（Ｓ−Ｄ間）を２７０μｍとし、トナー規制部材としてウレタンゴム製ブレードを当接させて用いた。現像バイアスとして直流バイアス成分に交流バイアス成分を重畳して用いた。また、加熱定着装置Ｈには図５，図６に示した定着装置を用い、加熱体３１の検温素子３１ｄの表面温度は１３０℃、加熱体２１−シリコンゴムの発泡体を下層に有するスポンジ加圧ローラ３３間の総圧は１０ｋｇ、加圧ローラとフィルムのニップは７ｍｍとし、定着フィルム３２には、転写材との接触面にＰＴＥＦ（高分子量タイプ）に導電性物質を分散させた低抵抗の離型層を有する厚さ５０μｍの耐熱性ポリイミドフィルムを使用した。
【０１６９】
以上の設定条件で、常温常湿（２５℃，６０％ＲＨ）、高温高湿（３０℃，８０％ＲＨ）環境下、１２枚（Ａ４サイズ）／分のプリントアウト速度で、トナー（Ａ）と比較用トナー（ａ）の各々を逐次補給しながら間歇モード（すなわち、１枚プリントアウトする毎に１０秒間現像器を休止させ、再起動時の予備動作でトナーの劣化を促進させるモード）で５０００枚のプリントアウト試験を行い、得られたプリントアウト画像を後述の項目について評価した。
【０１７０】
また、同時に用いた画像形成装置と上記トナーとのマッチングについても評価した。
【０１７１】
以上の評価結果を表３に示す。
【０１７２】
【表３】

【０１７５】
本発明の実施例、並びに、比較例中に記載の評価項目の説明とその評価基準について述べる。
【０１７６】
（プリントアウト画像評価）
〈１〉画像濃度
通常の複写機用普通紙（７５ｇ／ｍ^２ ）に所定の枚数のプリントアウト終了した時の画像濃度維持により評価した。尚、画像濃度は「マクベス反射濃度計」（マクベス社製）を用いて、原稿濃度が０．００の白地部分のプリントアウト画像に対する相対濃度を測定した。
Ａ：１．４０以上
Ｂ：１．３５以上、１．４０未満
Ｃ：１．００以上、１．３５未満
Ｄ：１．００未満
【０１７７】
〈２〉画像カブリ
所定の枚数のプリントアウト終了後のプリントアウト画像を用い、「リフレクトメータ」（東京電色社製）により測定した白地部分の白色度と転写紙の白色度の差から、カブリ濃度（％）を算出し、画像カブリを評価した。
Ａ：１．５％未満
Ｂ：１．５％以上、２．５％未満
Ｃ：２．５％以上、４．０％未満
Ｄ：４．０％以上
【０１７８】
〈３〉画像飛び散り
所定の枚数のプリントアウト終了後、図９（ａ）に示した「電」文字パターンを普通紙（７５ｇ／ｍ^２ ）と厚紙（１０５ｇ／ｍ^２ と１３５ｇ／ｍ^２ ）にプリントした際の文字周辺部へのトナー飛び散り（図９（ｂ）の状態）を目視で評価した。
Ａ：ほとんど発生せず。
Ｂ：軽微な飛び散りが見られる。
Ｃ：若干の飛び散りが見られる。
Ｄ：顕著な飛び散りが見られる。
【０１７９】
〈４〉画像中抜け
所定の枚数のプリントアウト終了後、図１０（ａ）に示した「驚」文字パターンを厚紙（１２８ｇ／ｍ^２ ）にプリントした際の文字の中抜け（図１０（ｂ）の状態）を目視で評価した。
Ａ：ほとんど発生せず。
Ｂ：軽微な中抜けが見られる。
Ｃ：若干の中抜けが見られる。
Ｄ：顕著な中抜けが見られる。
【０１８０】
〈５〉ドット再現性
所定の枚数のプリントアウト終了後、図８に示すチェッカー模様を普通紙（７５ｇ／ｍ^２ ）と厚紙（１０５ｇ／ｍ^２ ）にプリントアウトし、そのドット再現性を評価した。
Ａ：欠損２個以下／１００個
Ｂ：欠損３〜５個／１００個
Ｃ：欠損６〜１０個／１００個
Ｄ：欠損１１個以上／１００個
【０１８１】
（画像形成装置マッチング評価）
〈１〉現像スリーブとのマッチング
プリントアウト試験終了後、現像スリーブ表面への残留トナーの固着の様子とプリントアウト画像への影響を目視で評価した。
Ａ：未発生。
Ｂ：ほとんど発生せず。
Ｃ：固着があるが、画像への影響が少ない。
Ｄ：固着が多く、画像ムラを生じる。
【０１８２】
〈２〉感光体ドラムとのマッチング
プリントアウト試験終了後、感光体ドラム表面の傷や残留トナーの固着の発生状況とプリントアウト画像への影響を目視で評価した。
Ａ：未発生。
Ｂ：わずかに傷の発生が見られるが、画像への影響はない。
Ｃ：固着や傷があるが、画像への影響が少ない。
Ｄ：固着が多く、縦スジ状の画像欠陥を生じる。
【０１８３】
〈３〉中間転写体とのマッチング
プリントアウト試験終了後、中間転写体表面の傷や残留トナーの固着状況を目視で評価した。
Ａ：未発生
Ｂ：表面に残留トナーの存在が認められるものの画像への影響はない。
Ｃ：固着や傷があるが、画像への影響が少ない。
Ｄ：固着が多く、画像欠陥を生じる。
【０１８４】
〈４〉定着装置とのマッチング
プリントアウト試験終了後、定着フィルム表面の傷や残留トナーの固着状況を目視で評価した。
Ａ：未発生
Ｂ：わずかに固着が見られるものの、画像への影響はない。
Ｃ：固着や傷があるが、画像への影響が少ない。
Ｄ：固着が多く、画像欠陥を生じる。
【０１８５】
【発明の効果】
以上説明したように、本発明によれば、トナー粒子の粒子形状分布を精密に制御することにより、トナーに望ましい現像性と転写性を与えることが出来る。すなわち、平均径が２〜８μｍ、平均円形度が０．９６０〜０．９９５であり、該トナーが１０μｍを越える円相当径を有する粗粒子を０．０２〜３個数％含有しており、該粗粒子の平均円形度が０．９３０〜０．９７５とすることにより、トナーの耐久劣化が防止され、環境安定性に優れ、高品位な画像を長期にわたって形成することが出来る。又、画像形成装置とのマッチングも好適なものとなる。
【図面の簡単な説明】
【図１】本発明に好適な画像形成装置の概略的説明図である。
【図２】二成分現像剤用の現像装置の要部の拡大横断図である。
【図３】一成分現像剤用の現像装置の要部の拡大横断図である。
【図４】未転写トナーをリユースする画像形成装置の概略的説明図である。
【図５】本発明の実施例に用いた定着装置の要部の分解斜視図である。
【図６】本発明の実施例に用いた定着装置の非駆動時のフィルム状態を示した要部の拡大横断図である。
【図７】ワックス成分の内包化しているトナー粒子の断面の一例を示す模式図である。
【図８】トナーの現像特性をチェックする為のチェッカー模様の説明図である。
【図９】文字画像の中抜けの状態を示す模式図である。
【図１０】文字画像の飛び散りの状態を示す模式図である。
【図１１】本発明に好適な粉体処理装置システムの概略的外観図である。
【図１２】本発明に好適な粉体処理装置の要部の部分的断面図である。
【図１３】本発明に好適な粉体処理装置の回転ロータの斜視図である。
【符号の説明】
１ 感光体（静電潜像担持体）
２ 帯電ローラ
３ 露光
４ ４色現像器（４−１、４−２、４−３、４−４）
５ 中間転写体
６ 転写材
７ 転写ローラ
１１ 現像剤担持体
１３ 感光体ドラム
３０ ステー
３１ 加熱体
３１ａ ヒーター基板
３１ｂ 発熱体
３１ｃ 表面保護層
３１ｄ 検温素子
３２ 定着フィルム
３３ 加圧ローラ
３４ コイルばね
３５ フィルム端部規制フランジ
３６ 給電コネクター
３７ 断電部材
３８ 入口ガイド
３９ 出口ガイド（分離ガイド）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dry toner (hereinafter, referred to as a toner) used for a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet method, and the like, and an image forming method using the toner. It is. More specifically, the present invention relates to a toner used in an image recording apparatus that can be used in a copying machine, a printer, a facsimile, a plotter, and the like, and an image forming method using the toner.
[0002]
[Prior art]
Conventionally, many methods are known as electrophotography, but generally, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is formed. After developing with a toner to make a visible image, and transferring the toner image to a transfer material such as paper as necessary, the toner image is fixed on the transfer material by heat / pressure to obtain a final image.
[0003]
Various developing methods for visualizing an electrostatic latent image using toner are also known. For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade developing method described in U.S. Pat. No. 2,618,552, and U.S. Pat. No. 2,221,776. Many development methods are known, such as a powder cloud method, a fur brush development method, and a liquid development method described in the specification. Among these developing methods, in particular, a magnetic brush method, a cascade method, a liquid developing method and the like using a developer mainly composed of a toner and a carrier have been put to practical use. Each of these methods is an excellent method for obtaining a good image relatively stably, but has problems associated with the two-component developer such as deterioration of the carrier and fluctuation of the mixing ratio of the toner and the carrier.
[0004]
In order to solve such a problem, various developing methods using a one-component developer composed of only a toner have been proposed.
[0005]
In recent years, such copying apparatuses have begun to be used not only as office work copying machines for simply copying original documents, but also as printers as computer outputs or personal copies for individuals.
[0006]
For this reason, miniaturization, weight reduction, high speed, and high reliability have been strictly pursued, and machines have been configured with simple elements in various points.
[0007]
Particularly, in a printer or a facsimile, since it is desired to reduce the size of the image forming apparatus, a developing apparatus using one-component toner is often used.
[0008]
Under these circumstances, there is an increasing demand for high resolution in printers and facsimile machines as described above. For example, the resolution, which was initially 200 to 300 dpi (dot per inch), is now becoming 400 to 800 dpi, and moreover 1200 dpi. Similarly, copiers have been advanced in function by digitalization, and a development method of high resolution and high definition has been strongly demanded.
[0009]
Therefore, particularly in digital printers and copiers, the thickness of the photosensitive layer has been reduced in order to increase the definition of an electrostatic latent image. When such a thin-film photoreceptor is used, the potential contrast of the electrostatic latent image is reduced, so that the toner used for development has higher developability and also has durability enough to maintain the high developability. Is desired.
[0010]
In the one-component developing method, since the toner is developed in a chain form (generally called "spikes") at the time of development, the resolution in the horizontal direction of the image is likely to be lower than that in the vertical direction. As compared with the solid black image, the flying amount of the toner on the line image becomes excessive, the toner consumption increases, and the fidelity reproducibility of the image and the economy tend to be inferior. On the other hand, when a visible image is formed by the toner, a tailing phenomenon in which the toner runs out of the image part in a spike state and a phenomenon in which the toner scatters to the peripheral part of the image occur, which causes a reduction in resolution.
[0011]
Therefore, as a method of improving the image reproducibility, it is necessary to make the toner application on the toner carrier (developing sleeve) extremely thin and to shorten the spike of the toner. However, in the conventional toner, since a large stress is applied to the toner particles and the surface of the toner carrier in this method, deterioration of the toner surface, contamination of the surface of the toner carrier, fixation of the toner, and matching with the image forming apparatus are performed. Had a problem.
[0012]
On the other hand, in response to the demand for a high-resolution and high-definition developing method, JP-A-1-112253, JP-A-1-191156, JP-A-2-214156, JP-A-2-284158, and JP-A-2-284158. Japanese Patent Application Laid-Open Nos. 3-181952 and 4-162048 have proposed small particle size toners having a specific particle size distribution, but also have a problem of image quality deterioration and transferability due to toner deterioration as described above. I was
[0013]
In Japanese Patent Application Laid-Open No. 9-160283, the average particle diameter is 6 to 10 μm, the average circularity is 0.85 to 0.98, and the content of particles having a circularity of 0.85 or less is 10% by weight. %, Toner fluidity, charge rising property, and cleaning property with a cleaning blade are mentioned. However, toner durability and environmental stability due to toner particle size reduction are proposed. No consideration is given to the properties, and high-definition development has not been achieved.
[0014]
Further, in JP-A-9-197714, the ratio B / A of the 50% average diameter A to the 10% average diameter B of the developer particles is 40 to 80%, and the average circularity is 0.93 to 1.0. A developer has been proposed which considers the developer comprehensively by controlling the shape of the toner so that the ratio of the circularity of 0.85 or less is 3.0% or less. However, although a certain improvement is seen in the stability of the image density of the developer, a toner having a 50% average diameter exceeding 0.96 and a 50% average diameter of 8 μm or less is not considered at all. In fact, there is room for improvement for the above-mentioned problems.
[0015]
On the other hand, in recent years, from the viewpoint of environmental protection, the primary charging and transfer process using a corona discharge, which has been conventionally used, to the primary charging and transfer process using a photosensitive member contact member are becoming mainstream.
[0016]
For example, JP-A-63-149669 and JP-A-2-123385 have been proposed. These are related to a contact charging method and a contact transfer method. However, when a conductive elastic roller is brought into contact with an electrostatic latent image carrier and a voltage is applied to the conductive roller, the electrostatic latent image carrier is After uniformly charging, and then obtaining a toner image by an exposure and development process, the transfer material is passed through while pressing another conductive roller to which a voltage is applied to the electrostatic latent image carrier, and After the toner image on the latent image carrier is transferred to a transfer material, a transferred image is obtained through a fixing process.
[0017]
However, in such a roller transfer method that does not use corona discharge, the transfer member is brought into contact with the photosensitive member via the transfer material during transfer, so that the toner image formed on the photosensitive member is transferred to the transfer material. At this time, the toner images were pressed against each other, and a partial transfer failure called so-called “missing during transfer” occurred.
[0018]
Further, as the toner becomes smaller in particle size, the adhesion force (mirror image force, van der Waals force, etc.) of the toner particles to the photoreceptor becomes larger than the Coulomb force applied to the toner particles in transfer, resulting in transfer. The residual toner tends to increase.
[0019]
Furthermore, in the roller charging system, the physical and chemical action of the surface of the electrostatic latent image carrier due to the discharge generated between the charging roller and the electrostatic latent image carrier is larger than that of the corona charging system, and particularly, the organic charging device is used for the organic charging device. In combination with photoreceptor / blade cleaning, abrasion due to photoreceptor surface deterioration is likely to occur, and there is a problem in life.
[0020]
Therefore, it has been required that the toner and the photoreceptor used in such an image forming method have excellent releasability.
[0021]
Heretofore, the untransferred toner remaining on the photoreceptor without being transferred has been cleaned and removed by various methods, collected and discharged as so-called "waste toner", and has not been used again. Since the waste toner is treated as waste (waste plastic), the waste toner is reused from the viewpoint of effective use of resources, reduction of the waste, and consideration for living environment. Considerations have been widely made. If the waste toner can be reused, not only the above-mentioned effective use of the toner but also other advantages such as downsizing of the image forming apparatus can be considered.
[0022]
However, in practice, when the waste toner is reused, the image quality is adversely affected due to the reduction in image density and the fogging phenomenon, and a problem occurs in matching with the image forming apparatus.
[0023]
Therefore, the toner applied to the toner reuse as described above includes, in addition to the properties such as developability, environmental stability, low-temperature fixing property, anti-offset property, and storage stability, which are conventionally desired for the toner, external force. It is also required to have excellent mechanical strength and durability, and excellent transportability of waste toner to a developing portion.
[0024]
The various performances required for the above-mentioned toners are often contradictory to each other, and it is increasingly desired in recent years to satisfy them with high performance. Under these circumstances, the role of each toner constituent material plays a large role, and high functionality is required, and it is important to design an image forming system that brings out the excellent characteristics of the toner. However, there is not yet enough comprehensive response to comprehensively address the above issues.
[0025]
[Problems to be solved by the invention]
An object of the present invention is to significantly improve the drawbacks of the related art, improve developability and environmental stability, and realize a high-quality image stably over a long period of time. An object of the present invention is to provide a dry toner which is highly applicable to an electrophotographic process which does not cause a bad influence, and an image forming method using the toner.
[0026]
[Means for Solving the Problems]
The present invention is a dry toner containing at least a binder resin, a colorant and a wax component, and in a number-based circle-equivalent diameter-circularity scattergram measured by a flow-type particle image measuring device for the toner, The toner has a circle-equivalent number average diameter D1 of 2 to 8 μm, the toner contains 0.02 to 5% by number of coarse particles having a circle-equivalent diameter exceeding 10 μm, and the average circularity of the coarse particles is 0.9 to 0.990.
[0027]
Further, the present invention relates to an image forming method using the toner.
[0028]
As a result of intensive studies, the present inventors have found that by precisely controlling the shape distribution of the toner, it is possible to impart desirable developability and transferability as well as durability and environmental stability to the toner.
[0029]
That is, in the circle equivalent diameter-circularity scattergram based on the number of toners, the toner has an average circle equivalent number diameter of 2 to 8 μm and contains 0.02 to 5% by number of coarse particles having a circle equivalent diameter exceeding 10 μm. By precisely controlling the particle shape of the toner so that the average circularity of the coarse particles is 0.900 to 0.990, the developability and the transferability are improved in a well-balanced manner. In particular, the durability of the toner is improved, and the image scattering and dot reproducibility of the toner under high temperature and high humidity are improved.
[0030]
A good image can be obtained by setting the toner equivalent circle number average diameter to 2 to 8 μm, preferably 2 to 6 μm. In particular, by reducing the average diameter of the circle-equivalent number to 2 to 5 μm, the reproducibility of the contour portion of the image, particularly, the development of a character image or a line pattern becomes good. However, conventionally, when the particle size of the toner particles is reduced, the existence ratio of the toner having a small particle size is inevitably increased, so that it is difficult to uniformly charge the toner, and not only image fog occurs but also the toner surface Since they are susceptible to deterioration, they tend to cause problems in durability and environmental stability. Further, matching with the image forming apparatus is not sufficient.
[0031]
However, the toner of the present invention contains 0.02 to 5% by number of particles having a circle equivalent diameter of more than 10 μm in the circle equivalent diameter-circularity scattergram, and the average circularity of the coarse particles is 0.900. By setting it to 0.990, it is possible to greatly improve problems relating to the developability and durability of the toner and the environmental stability. The reason for this is that the presence of coarse particles having a specific shape in the toner normally reduces the regulating force of the toner layer thickness regulating member when forming a thin layer of toner on the toner carrier in the developing step. It is possible to minimize the deterioration of the toner surface due to strongly pressing the regulating member while maintaining a sufficient amount of toner coating even if it is made stronger. In addition, since the charge amount of the toner can be made higher than usual, even under high temperature and high humidity where a decrease in developability is likely to appear as an image defect, image scattering and dot reproducibility are improved and become good. . Further, even if the average particle diameter of the toner is reduced to 2 to 5 μm, the average circularity of the toner is set to 0.960 to 0.995, and coarse particles having an equivalent circle diameter of more than 10 μm are reduced to 0.1 μm. By setting the average circularity of the coarse particles to 0.930 to 0.975, not only the balance between the developability and the transferability is improved, but also the chargeability of the toner becomes uniform. High-resolution and high-definition image reproduction becomes possible.
[0032]
If the content of coarse particles having an equivalent circle diameter of more than 10 μm is less than 0.02% by number, the toner surface is significantly deteriorated, and the above-mentioned improvement effect cannot be expected. On the other hand, if the content of coarse particles exceeds 5% by number, selectivity is generated between particles having an average particle size during development and coarse particles are easily consumed without being consumed, so that image quality is deteriorated. Etc. are likely to occur. In addition, such coarse particles often have different mechanical strength and thermal characteristics as compared with those having an average particle diameter, and thus tend to cause a problem in matching with an image forming apparatus.
[0033]
The average circularity of the coarse particles must be between 0.900 and 0.990. If the average circularity is less than 0.900, the shape of the toner surface becomes non-uniform, adversely affecting the chargeability of the entire toner, and causing a problem in matching with the image forming apparatus. On the other hand, if the average circularity exceeds 0.990, the deterioration of the coarse particles themselves is promoted, which causes problems such as deterioration of image quality.
[0034]
Since the above-mentioned problems become apparent as the particle size of the toner becomes smaller, the average circularity of the coarse particles of the toner is 0.930-0. 975 is preferable.
[0035]
The circle equivalent diameter and circularity of the toner and the frequency distribution thereof in the present invention are used as a simple method for quantitatively expressing the shape of the toner. In the present invention, the flow type particle image measuring device FPIA The measurement was performed using Model -1000 (manufactured by Toa Medical Electronics Co., Ltd.), and calculated using the following equation.
Equivalent circle diameter = (particle projection area / π)^1/2  × 2
[0036]
[Outside 1]

[0037]
Here, the “particle projection area” is the area of the binarized toner image, and the “perimeter of the particle projection image” is defined as the length of a contour obtained by connecting the edge points of the toner image. .
[0038]
The circularity in the present invention is an index indicating the degree of unevenness of the toner. The circularity is 1.00 when the toner is perfectly spherical, and the circularity becomes smaller as the surface shape becomes more complicated.
[0039]
In the present invention, the circle-equivalent number average diameter D1 meaning the average value of the particle size frequency distribution based on the number of toners is as follows, where di is the particle size (center value) at the dividing point i of the particle size distribution, and fi is the frequency. It is calculated from the formula.
[0040]
[Outside 2]

[0041]
The average circularity c, which means the average value of the circularity frequency distribution, is calculated from the following equation, where the circularity (center value) at the dividing point i of the particle size distribution is ci and the frequency is fci.
[0042]
[Outside 3]

[0043]
As a specific measuring method, 10 ml of ion-exchanged water from which impurity solids and the like have been removed in advance in a container is prepared, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, and then further measured. Add 0.02 g of sample and disperse uniformly. As a means for dispersing, using a UH-50 ultrasonic dispersion type (manufactured by SMT Corporation) with a titanium alloy chip of 5φ attached as a vibrator, a dispersion treatment is performed for 5 minutes to obtain a dispersion for measurement. At this time, the dispersion is appropriately cooled so that the temperature of the dispersion does not exceed 40 ° C.
[0044]
For the measurement of the shape of the toner, using the above-mentioned flow type particle image measuring device, the concentration of the dispersion was readjusted so that the toner concentration at the time of measurement was 3000 to 10,000 particles / μl, and the number of toner particles was measured to be 1000 or more. I do. After the measurement, a binary frequency distribution diagram (scattergram) of the circle equivalent diameter and the circularity of the toner is obtained using the data.
[0045]
Examples of the binder resin used in the toner of the present invention include generally used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers. In a method of directly obtaining toner particles by a polymerization method, a monomer for forming them is used. Specifically, styrene; styrene-based monomers such as o (m-, p-)-methylstyrene and m (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, (meth) ) Propyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( (Meth) acrylate monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile and acrylamide It is preferably used. These may be used alone or generally in such a manner that the theoretical glass transition temperature (Tg) described in the published Polymer Handbook, 2nd edition III-P139-192 (manufactured by John Wiley & Sons) indicates 40 to 50 ° C. The monomers are appropriately mixed and used. If the theoretical glass transition temperature is less than 40 ° C., problems tend to occur in terms of storage stability and durability stability of the toner, while if it exceeds 75 ° C., the fixing point of the toner increases. In particular, in the case of a color toner for forming a full-color image, it is not preferable because the color mixing property of each color toner at the time of fixing is reduced, the color reproducibility is poor, and the transparency of the OHP image is reduced.
[0046]
The molecular weight of the binder resin is measured by gel permeation chromatography (GPC). In the case of a toner having a core-shell structure, a specific GPC measurement method is to extract the toner in advance using a Soxhlet extractor with a toluene solvent for 20 hours and then distilling off toluene with a rotary evaporator to extract the extract. An organic solvent (for example, chloroform or the like) that dissolves the low softening point substance but does not dissolve the outer shell resin is added to the extract, and the extract is sufficiently washed. A sample (THF solution) filtered through a solvent-resistant membrane filter having a diameter of 0.3 μm is measured using Waters 150C. The column configuration is such that A-801, 802, 803, 804, 805, 806, 807 manufactured by Showa Denko are connected, and the molecular weight distribution can be measured using a standard polystyrene resin calibration curve. The binder resin according to the present invention has a main peak molecular weight of 5,000 to 1,000,000, and a ratio (Mw / Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of 2 to 100 is shown in the present invention. preferable.
[0047]
The coloring agents used in the present invention include the following yellow coloring agents, magenta coloring agents, and cyan coloring agents. As black coloring agents, carbon black, magnetic substances, or the following yellow coloring agents / magenta coloring agents / cyan coloring agents. A mixture prepared by mixing agents and toning to black is used.
[0048]
As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, 180 and the like are preferably used.
[0049]
Examples of the magenta colorant include a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48; 2, 48; 3, 48; 4, 57; 1, 81; 1, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254 are particularly preferred.
[0050]
As the cyan coloring agent, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15; 1, 15; 2, 15; 3, 15; 4, 60, 62, 66, etc. can be particularly preferably used.
[0051]
These colorants can be used alone or as a mixture or in the form of a solid solution. The colorant is selected from the viewpoints of hue, saturation, lightness, weather resistance, OHP transparency, and dispersibility in toner particles. The amount of the coloring agent is preferably 1 to 20 parts by weight based on 100 parts by weight of the resin component.
[0052]
When a magnetic material is used as the black colorant, it is preferable to use 40 to 150 parts by weight with respect to 100 parts by weight of the resin, unlike other colorants.
[0053]
Examples of the wax component according to the present invention include petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam and derivatives thereof, montan wax and derivatives thereof, hydrocarbon waxes and derivatives thereof by the Fischer-Tropsch method, and polyolefins represented by polyethylene. Waxes and their derivatives, carnauba wax, candelilla wax, natural waxes and their derivatives, etc. Derivatives include oxides, block copolymers with vinyl monomers, graft-modified products, and higher aliphatic alcohols Fatty acids such as stearic acid and palmitic acid or compounds thereof; acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, etc., having a dissolution temperature of 40 to 80 ° C. in styrene monomers. It can be used anywhere as long as is.
[0054]
Among these, when polyolefin, hydrocarbon wax, petroleum wax, higher alcohol or higher ester obtained by Fischer-Tropsch method is used, the effect of improving developability and transferability is further enhanced.
[0055]
The above-mentioned wax component is preferably used in an amount of 1 to 30 parts by weight based on 100 parts by weight of the binder resin.
[0056]
Further, an antioxidant may be added to the wax component as long as the chargeability of the toner is not affected.
[0057]
When the wax component according to the present invention is observed in a tomographic plane of a toner using a transmission electron microscope (TEM), the wax component is practically formed into a spherical and / or spindle-shaped island shape in a state where the wax component is not compatible with the binder resin. Distributed.
[0058]
In the present invention, the dispersion state of the wax component as described above is defined as follows. That is, D4 × 0.9 or more with respect to the circle-equivalent weight average diameter D4 (μm), which means the average value of the weight-based particle size frequency distribution of the toner measured by the above-described flow type particle image measuring device, Ten tomographic planes of toner particles having a long diameter of D4 × 1.1 or less are selected. Then, the largest major axis r in the phase separation structure caused by the major axis R of the tomographic plane of each toner particle and the wax component present in the tomographic plane of the toner particle having the major axis R is measured, and r / Find the average value of R. When the average value of r / R is in a dispersed state that satisfies the average value of 0.5 ≦ r / R ≦ 0.95, the wax component is substantially spherical and / or spindle-shaped without being compatible with the binder resin. Have an island-like dispersion state.
[0059]
By dispersing the wax component as described above and including the wax component in the toner, it is possible to prevent the deterioration of the toner and the contamination of the image forming apparatus. In particular, when the average value of r / R is in a dispersion state satisfying 0.25 ≦ r / R ≦ 0.90, good chargeability is maintained and a toner image excellent in dot reproduction can be formed for a long period of time. It is preferable because it becomes possible. Further, since the wax component acts efficiently during heating, low-temperature fixability and offset resistance are satisfied. Further, when a desired shape distribution of the toner is obtained, even if the shape and the surface of the toner particles are processed by an impact type powder processing apparatus using a rotating blade as described later, the performance of the toner is deteriorated and the processing performance of the processing apparatus is reduced. It is possible to prevent the fusion of the toner beforehand, and it is possible to give the toner desired characteristics by precisely controlling the shape distribution of the toner.
[0060]
In the present invention, as a specific method for observing the tomographic plane of the toner particles, the toner particles are obtained by sufficiently dispersing the toner particles in a room-temperature-curable epoxy resin and then curing the same at an ambient temperature of 40 ° C. for 2 days. The cured product is stained with ruthenium tetroxide and, if necessary, osmium tetroxide, and then sliced using a microtome with diamond teeth. The flake-shaped sample is cut out, and the morphology of the toner particles is determined using a transmission electron microscope (TEM). Is measured. In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to give a contrast between materials by utilizing a slight difference in crystallinity between the wax component used and the resin constituting the outer shell. FIG. 7 shows a typical example. In the toner particles obtained in Examples described later, it was observed that the wax component was included in the outer shell resin.
[0061]
As the charge control agent used in the present invention, a known charge control agent can be used, but a charge control agent having a high charging speed and capable of stably maintaining a constant charge amount is preferable. Further, when the toner particles are directly polymerized, a charge control agent having no polymerization inhibition and having no solubilized substance in an aqueous dispersion medium is particularly preferable. Specific examples of the compound include a metal compound of an aromatic carboxylic acid such as salicylic acid, naphthoic acid, and dicarboxylic acid as a negative charge control agent; a polymer compound having a sulfonic acid or carboxylic acid group in a side chain; a boron compound; Compounds; silicon compounds; curryxarene and the like. Examples of the positive charge control agent include a quaternary ammonium salt; a polymer compound having the quaternary ammonium salt in a side chain; a guanidine compound; and an imidazole compound. The charge control agent is preferably used in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the resin. However, the addition of a charge control agent is not essential in the present invention, and in the case of using a two-component developing method, utilizing triboelectric charging with a carrier, and in the case of using a non-magnetic one-component blade coating developing method, By positively utilizing frictional charging with the blade member or the sleeve member, it is not necessary to necessarily include a charge control agent in the toner particles.
[0062]
The addition of an inorganic fine powder to the toner of the present invention is a preferred embodiment for improving developability, transferability, charging stability, fluidity, and durability. As the inorganic fine powder, known ones can be used, but it is particularly preferable to be selected from silica, alumina, titania or a double oxide thereof. Further, silica is more preferable. For example, as the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide and an alkoxide, and a so-called wet silica produced from an alkoxide, a water glass and the like, and a dry silica called a fumed silica can be used. However, there are few silanol groups on the surface and inside the silica fine powder.₂  O, SO₃  ^2-Dry silica with less production residue such as is preferred. In the case of fumed silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the manufacturing process. Is also included.
[0063]
The inorganic fine powder used in the present invention has a specific surface area of 30 m by nitrogen adsorption measured by the BET method.²  / G or more, especially 50 to 400 m²  / G gives good results, and 0.1 to 8 parts by mass, preferably 0.5 to 5 parts by mass, more preferably more than 1.0, of silica fine powder with respect to 100 parts by mass of toner. It is particularly preferable to use up to 3.0 parts by mass.
[0064]
The inorganic fine powder used in the present invention may contain a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, a silane coupling agent, a functional group for the purpose of hydrophobization, charge control, etc., if necessary. It is possible and preferable to use a silane coupling agent, a treating agent such as an organosilicon compound, an organotitanium compound, or a combination of various treating agents.
[0065]
According to the BET method, the specific surface area was determined by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device Autosoap 1 (manufactured by Yuasa Ionics) and calculating the specific surface area using the BET multipoint method.
[0066]
In order to maintain a high charge amount and achieve low consumption and high transfer rate, it is more preferable that the inorganic fine powder be treated with at least silicone oil.
[0067]
In the toner of the present invention, other additives such as lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder; cerium oxide powder, silicon carbide powder, titanium Abrasives such as strontium acid powder; fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents; or conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder, and vice versa. Polar organic fine particles and inorganic fine particles can be used in small amounts as a developing property improver.
[0068]
As a method of producing the toner of the present invention, a resin, a release agent comprising a low softening point substance, a colorant, after uniformly dispersing a charge control agent and the like using a pressure kneader, an extruder or a media disperser, After colliding with a target mechanically or under a jet stream to pulverize to a desired toner particle size (if necessary, a process of smoothing and spheroidizing the toner particles is added), and further through a classification process, a particle size distribution In addition to a method for producing a toner by a pulverization method for making a toner into a sharpened toner, a method of obtaining a spherical toner by atomizing a molten mixture into the air using a disk or a multi-fluid nozzle described in JP-B-56-13945 or the like. The toner is directly produced by using the suspension polymerization method described in JP-B-36-10231, JP-A-59-53856 and JP-A-59-61842. Polymerization method, a dispersion polymerization method in which an aqueous organic solvent in which the obtained polymer is soluble in the monomer is insoluble, and a toner is formed by directly polymerizing in the presence of a water-soluble polar polymerization initiator by directly forming a toner using an aqueous organic solvent. The toner can be manufactured using an emulsion polymerization method represented by a free polymerization method.
[0069]
In a method of producing a toner using a pulverization method, it is difficult to keep the shape of the toner within a desired circularity frequency distribution range, and in the melt spraying method, a certain degree of circularity can be obtained. The obtained toner tends to have a wide particle size distribution, and it is difficult to control the surface state of the toner. On the other hand, in the dispersion polymerization method, the obtained toner has an extremely sharp particle size distribution, but the production equipment is not suitable from the viewpoints of narrow selection of materials to be used and the use of organic solvents in terms of waste solvent treatment and solvent flammability. It is complicated and easily complicated. The emulsion polymerization method represented by soap-free polymerization is effective because the particle size distribution of the toner is relatively uniform, but when the used emulsifier or polymerization initiator terminal is present on the surface of the toner particles, the environmental characteristics are likely to deteriorate.
[0070]
In the present invention, it is possible to control the circularity frequency distribution of the toner, under normal pressure, or a pressure-sensitive emulsifier polymerization method or a suspension polymerization method under which a toner having a small particle size can be obtained relatively easily. A method of shaping the polymer obtained beforehand using a medium, directly impacting the polymer against a pressure impingement plate, or freezing the obtained polymer in an aqueous system, salting or surface charge In particular, a coagulation method of uniting, coagulating, and coalescing particles having the following formulas in consideration of conditions such as pH is particularly preferable. Further, a seed polymerization method in which a monomer is further adsorbed on the obtained polymer particles and then polymerized using a polymerization initiator can also be suitably used in the present invention.
[0071]
When the direct polymerization method is used as a toner production method, the control of the circularity frequency distribution and particle size distribution of the toner is performed by changing the type and amount of a poorly water-soluble inorganic salt or dispersant that acts as a protective colloid, or by using a machine. Predetermined toner particles can be obtained by controlling appropriate device conditions (for example, the peripheral speed of the rotor, the number of baths, stirring conditions such as the shape of stirring blades and the shape of the container), or the solid content concentration in an aqueous solution.
[0072]
When a toner is produced by a direct polymerization method, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1 Azo or diazo polymerization initiators such as' -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide And peroxide polymerization initiators such as methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide. The amount of the polymerization initiator used varies depending on the desired degree of polymerization, but is generally used in an amount of 0.5 to 20% by weight based on the polymerizable monomer. The type of the polymerization initiator varies slightly depending on the polymerization method, but is used alone or in combination with reference to the 10-hour half-life temperature.
[0073]
In order to control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor or the like may be further added and used.
[0074]
When utilizing a suspension polymerization method using a dispersion stabilizer as a toner production method, as the dispersion stabilizer to be used, as an inorganic compound, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, Examples include magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salts of carboxymethyl cellulose, polyacrylic acid and salts thereof, and starch. These can be used by dispersing them in an aqueous phase. It is preferable to use 0.2 to 20 parts by weight of these dispersion stabilizers based on 100 parts by weight of the polymerizable monomer.
[0075]
When an inorganic compound is used as the dispersion stabilizer, a commercially available one may be used as it is, but fine particles of the inorganic compound may be produced in a dispersion medium in order to obtain fine particles. For example, in the case of tricalcium phosphate, it is preferable to mix an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring.
[0076]
In order to finely disperse these dispersion stabilizers, 0.001 to 0.1 parts by weight of a surfactant may be used in combination. This is to promote the desired action of the dispersion stabilizer, for example, 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.
[0077]
When the direct polymerization method is used as the method for producing the toner used in the present invention, the following production methods are possible.
[0078]
A wax component composed of a low softening point substance, a colorant, a charge control agent, a polymerization initiator, and other additives were added to the polymerizable monomer, and the mixture was uniformly dissolved or dispersed with a homogenizer, an ultrasonic disperser, or the like. The monomer composition is dispersed in an aqueous phase containing a dispersion stabilizer using a conventional stirrer, homomixer, homogenizer, or the like. Preferably, the granulation is performed by adjusting the stirring speed and the stirring time so that the droplets of the monomer composition have a desired size of the toner particles. After that, by the action of the dispersion stabilizer, the stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented. The polymerization is preferably carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. The temperature may be raised in the latter half of the polymerization reaction, and further, for the purpose of improving durability in the image forming method of the present invention, in the latter half of the reaction to remove unreacted polymerizable monomers, by-products, and the like, Alternatively, a part of the aqueous medium may be distilled off from the reaction system after the completion of the reaction. After the reaction, the generated toner particles are collected by washing and filtration, and dried. In the suspension polymerization method, 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 composition.
[0079]
On the other hand, it is one of the preferred embodiments of the present invention to apply a treatment to the shape and surface of the toner particles by an impact type powder processing apparatus using a rotating blade in order to obtain a desired shape distribution of the toner.
[0080]
As an impact type powder processing apparatus using a rotating blade, Y. Takayama, Y .; Kikuchi and K.K. Ono: ZAIRYO GIJUTSU Vol. 8, No. 8, 10, (1990), a known production apparatus such as a hybridization system manufactured by Nara Machinery Co., Ltd. or an impact-type pulverizer manufactured by Turbo Kogyo Co., Ltd. can be used. It is preferable to use the powder processing apparatus shown in FIGS. 11 to 13 in order to perform a precise treatment, precisely control a desired shape distribution, and achieve high productivity.
[0081]
An impact type powder processing apparatus using a rotating blade suitable for the present invention will be specifically described with reference to the drawings.
[0082]
FIG. 11 is an example of a powder shape processing apparatus system incorporating a powder processing apparatus A suitable for the present invention, FIG. 12 is a partial cross-sectional view of the powder processing apparatus A, and FIG. It is a perspective view of the rotary drive shaft which has a step.
[0083]
The powder processing apparatus A shown in FIG. 12 includes first to fourth cylindrical processing chambers 79a to 79d connected to each other in a cylindrical casing 51, and a rotating rotor 52a having ten blades each. 52d are included in a state fixed to the rotation drive shaft 53. The rotation drive shaft 53 is supported by bearings 61 and 62, and the rotation of the electric motor 84 is transmitted by a belt hung on a pulley 54 at the lower end, and rotates at high speed in the direction of the arrow.
[0084]
The toner particles in the fixed amount supply device 66 shown in FIG. 11 are provided at the center of the front wall 83 of the first cylindrical processing chamber 79a through the vibration feeder 65, the hopper 82 and the powder supply tube 81. The air is introduced into the first cylindrical processing chamber 79a together with air from the powder supply port 80 by the suction force of the suction probe 74. The toner particles introduced into the first cylindrical processing chamber 79a are generated by the rotation of the rotating rotor 52a having ten blades, and the airflow from the center direction to the side wall 57a causes the side wall of the first cylindrical processing chamber 79a. The surface of the rotary rotor 52a and the first rear wall 58a pass through the gap between the side wall 57a and the blade 59a, and undergo surface treatment while convection in the space of the first cylindrical processing chamber 79a. (Also referred to as a guide plate or a second front wall) and is discharged from a first powder discharge port 60a provided in a central portion of the first rear wall 58a. In the processing apparatus A, the first powder discharge port 60a also serves as a powder supply port of the second cylindrical processing chamber 79b, and the toner particles pass through the first powder discharge port 60a to the second powder discharge port 60a. It is introduced into the central part of the cylindrical processing chamber 79b. In the second cylindrical processing chamber 79b, the toner particles surface-treated in the first cylindrical processing chamber 79a are supplied to the rotating rotor 52b having ten blades in the same manner as in the first cylindrical processing chamber 79a. The surface is further processed by rotation. Further, the toner particles surface-treated in the second cylindrical processing chamber 79b are subsequently surface-treated in the third cylindrical processing chamber 79c and the fourth cylindrical processing chamber 79d.
[0085]
The toner particles surface-treated in the fourth cylindrical processing chamber 79d pass through a fourth powder discharge port 60d provided at the center of the guide plate 58d, and are discharged in a tangential direction of the cylindrical casing 51. Via the outlet 63a of the pipe 63, through the connecting pipe 67, it is stored in the cyclone 70. The surface-treated toner particles stored in the cyclone 70 are appropriately taken out from the valve 71.
[0086]
The shape distribution of the toner includes the shape of the cylindrical processing chamber of the powder processing apparatus, the shape and number of blades fixed to the rotating rotor, the number of fixed positions, the number of rotations of the rotating rotor, and the number of toner particles in the cylindrical processing chamber. Can be adjusted as appropriate depending on the residence time, particle concentration, ambient temperature during processing, and the like.
[0087]
Next, an image forming method to which the toner of the present invention is applied will be described below with reference to the accompanying drawings.
[0088]
In the apparatus system shown in FIG. 1, the developing units 4-1, 4-2, 4-3, and 4-4 respectively include a developer having a cyan toner, a developer having a magenta toner, a developer having a yellow toner, and black. A developer having a toner is introduced, and the electrostatic charge image formed on the electrostatic latent image carrier (for example, the photosensitive drum) 1 is developed by a magnetic brush developing method or a non-magnetic one-component method, and the toner images of each color are exposed. It is formed on the body drum 1.
[0089]
The toner of the present invention can be mixed with a magnetic carrier and developed using, for example, a developing unit as shown in FIG. Specifically, it is preferable to perform development in a state where the magnetic brush is in contact with the photosensitive drum 13 while applying an alternating electric field. A distance (SD distance) B between the developer carrier (developing sleeve) 11 and the photosensitive drum 13 of 100 to 1000 μm is favorable for preventing carrier adhesion and improving dot reproducibility. If it is smaller than 100 μm, the supply of the developer tends to be insufficient and the image density is lowered. If it is larger than 1000 μm, the lines of magnetic force from the magnet S1 are widened, the density of the magnetic brush is reduced, and the dot reproducibility is poor or the carrier is restrained. And the carrier is likely to adhere.
[0090]
The voltage (Vpp) between the peaks of the alternating electric field is preferably 500 to 5000 V, and the frequency (f) is 500 to 10000 Hz, preferably 500 to 3000 Hz. In this case, various waveforms such as a triangular wave, a rectangular wave, a sine wave, and a waveform having a changed duty ratio can be used. If the applied voltage is lower than 500 V, it is difficult to obtain a sufficient image density, and it may not be possible to satisfactorily collect fog toner in a non-image area. If the voltage exceeds 5000 V, the electrostatic image may be disturbed via the magnetic brush, which may cause deterioration in image quality.
[0091]
By using a two-component developer having a well-charged toner, the fog removal voltage (Vback) can be reduced, and the primary charge of the photoconductor can be reduced, so that the life of the photoconductor can be extended. it can. Vback is preferably 150 V or less, more preferably 100 V or less, depending on the development system.
[0092]
As the contrast potential, 200 V to 500 V is preferably used so that a sufficient image density can be obtained.
[0093]
When the frequency is lower than 500 Hz, although it is related to the process speed, charge injection into the carrier occurs, and the image quality may be deteriorated by carrier adhesion or disturbing the latent image. When the frequency exceeds 10,000 Hz, the toner cannot follow the electric field, and the image quality is liable to be reduced.
[0094]
The contact width (developing nip C) of the magnetic brush on the developing sleeve 11 with the photosensitive drum 13 is preferably 3 to 8 mm in order to obtain sufficient image density, perform excellent dot reproducibility, and perform development without carrier adhesion. It is to be. If the developing nip C is smaller than 3 mm, it is difficult to sufficiently satisfy the sufficient image density and dot reproducibility. If the developing nip C is larger than 8 mm, packing of the developer occurs, which stops the operation of the machine or causes carrier adhesion. It is difficult to sufficiently suppress this. As a method of adjusting the developing nip, the nip width is appropriately adjusted by adjusting the distance A between the developer regulating member 18 and the developing sleeve 11 or adjusting the distance B between the developing sleeve 11 and the photosensitive drum 13.
[0095]
Particularly, in the output of a full-color image in which halftone is emphasized, three or more developing units for magenta, cyan, and yellow are used, and the developer and the developing method of the present invention are used. In combination with the formed developing system, it is possible to develop the dot latent image faithfully without being affected by the magnetic brush and disturbing the image. Also in the transfer step, a high transfer rate can be achieved by using the toner of the present invention, so that high image quality can be achieved in both the halftone portion and the solid portion.
[0096]
Further, by using the toner of the present invention together with the initial improvement of image quality, the effect of the present invention without image quality deterioration can be sufficiently exerted even when copying a large number of sheets.
[0097]
The toner of the present invention can be suitably used for one-component development. An example of an apparatus for developing an electrostatic image formed on an electrostatic latent image carrier is shown, but is not necessarily limited thereto.
[0098]
In FIG. 3, reference numeral 25 denotes an electrostatic latent image carrier (photosensitive drum), and a latent image is formed by an electrophotographic process means or an electrostatic recording means. Reference numeral 24 denotes a toner carrier (developing sleeve), which is formed of a non-magnetic sleeve made of aluminum, stainless steel, or the like.
[0099]
The substantially right half peripheral surface of the developing sleeve 24 is always in contact with the toner reservoir in the toner container 21, and the toner near the developing sleeve surface is brought into contact with the developing sleeve surface by the magnetic force of the magnetic generating means in the sleeve and / or by the electrostatic force. Adhered and held.
[0100]
In the present invention, the surface roughness Ra (μm) of the toner carrier is set to be 1.5 or less. Preferably it is 1.0 or less. More preferably, it is 0.5 or less.
[0101]
By controlling the surface roughness Ra to 1.5 or less, the ability to transport toner particles of the toner carrier is suppressed, the toner layer on the toner carrier is made thinner, and the toner carrier and the toner Since the number of times of contact increases, the chargeability of the toner is also improved, so that the image quality is synergistically improved.
[0102]
If the surface roughness Ra of the toner carrier exceeds 1.5, not only is it difficult to reduce the thickness of the toner layer on the toner carrier, but also the chargeability of the toner is not improved, so that an improvement in image quality cannot be expected. .
[0103]
In the present invention, the surface roughness Ra of the toner carrier is measured based on JIS surface roughness “JISB0601” using a surface roughness measuring device (Surfcoder SE-30H, manufactured by Kosaka Laboratory Co., Ltd.). It corresponds to the center line average roughness. Specifically, a 2.5 mm portion as the measurement length a is extracted from the roughness curve in the direction of the center line, the center line of the extracted portion is the X axis, the longitudinal magnification direction is the Y axis, and the roughness curve is When y = f (x), the value obtained by the following equation is expressed in micrometers (μm).
[0104]
[Outside 4]

[0105]
As the toner carrier used in the present invention, for example, a cylindrical or belt-shaped member made of stainless steel, aluminum, or the like is preferably used. If necessary, the surface may be coated with a metal, a resin, or the like, or may be coated with a resin in which fine particles such as a resin, a metal, carbon black, and a charge control agent are dispersed.
[0106]
In the present invention, by setting the surface moving speed of the toner carrier to be 1.05 to 3.0 times the surface moving speed of the electrostatic latent image carrier, the toner layer on the toner carrier is Since an appropriate stirring effect is received, faithful reproduction of the electrostatic latent image is further improved.
[0107]
If the surface moving speed of the toner carrier is less than 1.05 times the surface moving speed of the electrostatic latent image carrier, the stirring effect of the toner layer becomes insufficient, and good image formation cannot be expected. . Also, when developing an image that requires a large amount of toner over a large area, such as a solid black image, the amount of toner supplied to the electrostatic latent image is insufficient and the image density is reduced. On the other hand, if it exceeds 3.0, in addition to the various problems caused by the excessive charging of the toner as described above, deterioration of the toner due to mechanical stress and adhesion of the toner to the toner carrier are generated and accelerated, which is not preferable. .
[0108]
The toner T is stored in the hopper 21 and is supplied onto the developing sleeve by the supply member 22. As the supply member, a supply roller made of a porous material such as a foamed material such as a flexible polyurethane foam is preferably used. The supply roller is rotated with respect to the developing sleeve in a forward or reverse direction at a non-zero relative speed, and at the same time as supplying the toner onto the developing sleeve, stripping off the developed toner (undeveloped toner) on the sleeve is performed. At this time, the contact width of the supply roller to the developing sleeve is preferably 2.0 to 10.0 mm, more preferably 4.0 to 6.0 mm, in consideration of the balance between toner supply and stripping. On the other hand, excessive stress is inevitably applied to the toner, and the aggregation of the toner due to the deterioration of the toner is increased, or the fusion and fixation of the toner to the developing sleeve and the supply roller are easily caused. Is excellent in fluidity and releasability, and has durability stability, and thus is preferably used in a developing method having the supply member. Further, a brush member made of a resin fiber such as nylon or rayon may be used as the supply member. These supply members use a non-magnetic one-component toner that cannot utilize a magnetic binding force. It is extremely effective in a one-component developing method, but may be used in a one-component developing method using a magnetic one-component toner.
[0109]
The toner supplied onto the developing sleeve is thinly and uniformly applied by the regulating member. The toner thinning regulating member is a doctor blade such as a metal blade or a magnetic blade disposed at a predetermined gap from the developing sleeve. Alternatively, instead of the doctor blade, a rigid roller or a sleeve made of metal, resin, ceramic, or the like may be used, and a magnet generating means may be provided inside thereof.
[0110]
Further, an elastic body such as an elastic blade or an elastic roller for press-applying the toner may be used as a regulating member for thinning the toner. For example, in FIG. 3, the elastic blade 23 has its base, which is the upper side, fixedly held on the developer container 21 side, and its lower side flexes in the forward or reverse direction of the developing sleeve 24 against the elasticity of the blade. In this state, the inner surface of the blade (the outer surface in the case of the opposite direction) is brought into contact with the surface of the sleeve 24 with an appropriate elastic pressure. According to such an apparatus, it is possible to obtain a dense toner layer that is stable against environmental changes. Although the reason is not always clear, it is assumed that the elastic body forcibly rubs against the surface of the developing sleeve, so that charging is always performed in the same state regardless of a change in behavior due to an environmental change of the toner.
[0111]
On the other hand, the toner tends to be excessively charged and the toner easily fuses on the developing sleeve or the elastic blade. However, the toner used in the present invention is preferably used because it has excellent releasability and stable triboelectric charging. .
[0112]
For the elastic body, it is preferable to select a material of a triboelectric series suitable for charging the toner to a desired polarity. Rubber elastic bodies such as silicone rubber, urethane rubber, NBR; synthetic resin elastic bodies such as polyethylene terephthalate A metal elastic body such as stainless steel, copper or phosphor bronze can be used. Further, a composite thereof may be used.
[0113]
Further, when durability is required for the elastic body and the toner carrier, it is preferable that a resin or rubber is bonded to the metal elastic body so as to hit the sleeve contact portion, or the metal elastic body is coated.
[0114]
Further, an organic substance or an inorganic substance may be added to the elastic body, may be melt-mixed, or may be dispersed. For example, the chargeability of the toner can be controlled by adding a metal oxide, metal powder, ceramics, carbon allotrope, whisker, inorganic fiber, dye, pigment, surfactant, and the like. In particular, when the elastic body is a molded body such as rubber or resin, fine particles of metal oxide such as silica, alumina, titania, tin oxide, zirconia, and zinc oxide, carbon black, a charge control agent generally used for toner And the like.
[0115]
Further, by applying a DC electric field and / or an AC electric field to the developing blade serving as the regulating member, the supply roller serving as the supplying member, and the brush member, the regulating portion on the developing sleeve for the action of loosening the toner includes The uniform thin layer coating property and the uniform charging property are further improved, and the supply / stripping of the toner is more smoothly performed at the supply portion, so that a sufficient image density can be achieved and a high quality image can be obtained.
[0116]
The contact pressure between the elastic body and the toner carrier is 0.1 kg / m or more, preferably 0.3 to 25 kg / m, more preferably 0.5 to 12 kg as a linear pressure in the generatrix direction of the toner carrier. / M is effective. As a result, the aggregation of the toner can be effectively released, and the charge amount of the toner can be instantaneously increased. If the contact pressure is less than 0.1 kg / m, it becomes difficult to apply the toner uniformly, and the charge amount distribution of the toner becomes broad, causing fogging and scattering. On the other hand, when the contact pressure exceeds 25 kg / m, a large pressure is applied to the toner, which is not preferable because the toner is deteriorated or a toner aggregate is generated. Further, a large torque is required to drive the toner carrier, which is not preferable.
[0117]
The gap α between the electrostatic latent image carrier and the toner carrier is preferably set to 50 to 500 μm, and the gap between the doctor blade and the toner carrier is preferably set to 50 to 400 μm.
[0118]
It is most preferable that the layer thickness of the toner layer on the toner carrier is smaller than the gap α between the electrostatic latent image carrier and the toner carrier. The thickness of the toner layer may be regulated to such an extent that the toner layer contacts the electrostatic latent image carrier.
[0119]
On the other hand, by applying an alternating electric field between the toner carrier and the electrostatic latent image carrier by the bias power supply 26, the movement of the toner from the toner carrier to the electrostatic latent image carrier is facilitated. Image can be obtained. Vpp of the alternating electric field is 100 V or more, preferably 200 to 3000 V, and more preferably 300 to 2000 V. Further, f is used at 500 to 5000 Hz, preferably at 1000 to 3000 Hz, and more preferably at 1500 to 3000 Hz. In this case, a waveform such as a rectangular wave, a sine wave, a sawtooth wave, and a triangular wave can be applied. Also, asymmetrical AC biases having different positive and reverse voltages and times can be used. It is also preferable to superimpose a DC bias.
[0120]
The electrostatic latent image carrier is a-Se, Cds, ZnO₂  , OPC, a photosensitive drum or a photosensitive belt having a photoconductive insulating material layer such as a-Si.
[0121]
As the electrostatic latent image carrier, a photosensitive member having an amorphous silicon photosensitive layer or an organic photosensitive layer is preferably used.
[0122]
As the organic photosensitive layer, the photosensitive layer may contain a charge generating substance and a substance having charge transport performance in the same layer, may be a single layer type, or may be a function-separated type photosensitive layer in which the charge transport layer is a component of the charge generating layer. It may be. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated on a conductive substrate in this order is one of preferred examples.
[0123]
As the binder resin of the organic photosensitive layer, a polycarbonate resin, a polyester resin, and an acrylic resin are particularly excellent in transferability and cleaning property, and poor cleaning, fusion of a toner to a photoconductor, and filming of an external additive hardly occur.
[0124]
In the charging step, there are a system that is not in contact with the electrostatic latent image carrier 1 using a corona charger, and a contact system that uses a roller or the like, and both systems are used. For efficient uniform charging, simplification, and low ozone generation, a contact type as shown in FIG. 1 is preferably used.
[0125]
The charging roller 2 basically has a core 2b at the center and a conductive elastic layer 2a formed on the outer periphery thereof. The charging roller 2 is pressed against the surface of the electrostatic latent image carrier 1 with a pressing force, and is driven to rotate as the electrostatic latent image carrier 1 rotates.
[0126]
As a preferable process condition when the charging roller is used, the contact pressure of the roller is 5 to 500 g / cm, and when the AC voltage is superimposed on the DC voltage, the AC voltage is 0.5 to 5 kVpp and the AC voltage is 0.5 to 5 kVpp. The frequency is 50 Hz to 5 kHz, the DC voltage is ± 0.2 to ± 1.5 kV, and when only the DC voltage is used, the DC voltage is ± 0.2 to ± 5 kV.
[0127]
Other charging means include a method using a charging blade and a method using a conductive brush. These contact charging means are effective in that high voltage is not required and generation of ozone is reduced.
[0128]
The material of the charging roller and the charging blade as the contact charging means is preferably a conductive rubber, and a release coating may be provided on the surface thereof. Nylon-based resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), or the like can be used as the release coating.
[0129]
Further, the toner image on the electrostatic latent image carrier is transferred to the intermediate transfer body 5 to which a voltage (for example, ± 0.1 to ± 5 kV) is applied. The surface of the electrostatic latent image carrier is cleaned by cleaning means 9 having a cleaning blade 8.
[0130]
The intermediate transfer member 5 is composed of a pipe-shaped conductive core 5b and a medium-resistance elastic layer 5a formed on the outer peripheral surface thereof. The core metal 5b may be formed by applying conductive plating to a plastic pipe.
[0131]
The medium-resistance elastic layer 5a is made of an elastic material such as silicone rubber, Teflon rubber, chloroprene rubber, urethane rubber, EPDM (ethylene propylene diene terpolymer), carbon black, zinc oxide, tin oxide, or silicon carbide. And an electric resistance value (volume resistivity) of 10⁵  ~ 11¹¹This is a solid or foamed layer adjusted to a medium resistance of Ω / cm.
[0132]
The intermediate transfer member 5 is provided so as to be supported in parallel with the electrostatic latent image carrier 1 and in contact with the lower surface of the electrostatic latent image carrier 1, and has the same peripheral speed as that of the electrostatic latent image carrier 1. To rotate in the same direction at the contact portion.
[0133]
The first color toner image formed and carried on the surface of the electrostatic latent image carrier 1 passes through a transfer nip where the electrostatic latent image carrier 1 and the intermediate transfer body 5 are in contact with each other. The transfer is performed on the outer surface of the intermediate transfer body 5 by the electric field formed in the transfer nip area by the applied transfer bias, and then, the second color, the third color, and the fourth color are sequentially transferred.
[0134]
If necessary, the surface of the intermediate transfer body 5 is cleaned by the detachable cleaning means 10 after the transfer of the toner image to the transfer material. When there is a toner image on the intermediate transfer member, the cleaning unit 10 is separated from the surface of the intermediate transfer member so as not to disturb the toner image.
[0135]
A transfer unit is provided in parallel with the intermediate transfer body 5 and is brought into contact with the lower surface of the intermediate transfer body 5. The transfer unit 7 is, for example, a transfer roller or a transfer belt. Rotate in the clockwise direction of the arrow at speed. The transfer unit 7 may be disposed so as to directly contact the intermediate transfer member 5, or a belt or the like may be disposed so as to contact between the intermediate transfer member 5 and the transfer unit 7.
[0136]
In the case of a transfer roller, the transfer roller has a basic configuration including a central core bar 7b and a conductive elastic layer 7a formed on the outer periphery thereof.
[0137]
A general material can be used for the intermediate transfer member and the transfer roller. By setting the volume resistivity of the elastic layer of the transfer roller smaller than the volume resistivity of the elastic layer of the intermediate transfer body, the voltage applied to the transfer roller can be reduced, and a good toner image can be formed on the transfer material. In addition, the winding of the transfer material around the intermediate transfer member can be prevented. In particular, it is particularly preferable that the volume specific resistance of the elastic layer of the intermediate transfer member is at least 10 times the volume specific resistance of the elastic layer of the transfer roller.
[0138]
For example, the conductive elastic layer 7b of the transfer roller 7 has a volume resistance of 10 such as polyurethane or ethylene-propylene-diene terpolymer (EPDM) in which a conductive material such as carbon is dispersed.⁶  -10¹⁰It is made of an elastic material of about Ωcm. A bias is applied to the metal core 7a from a constant voltage power supply. The bias condition is preferably ± 0.2 to ± 10 kV.
[0139]
The toner of the present invention has a high transfer efficiency in the transfer step, a small amount of untransferred toner, and an excellent cleaning property, so that filming hardly occurs on the electrostatic latent image carrier. Furthermore, even when a multi-sheet durability test is performed, the toner of the present invention has less embedding of the external additive on the toner particle surface and is less likely to deteriorate on the toner surface than the conventional toner, so that good image quality is maintained for a long time. I can do it. In particular, an image forming apparatus having a so-called reuse mechanism for removing transfer residual toner on an electrostatic latent image carrier or an intermediate transfer member as shown in FIG. 4 by a cleaning means such as a cleaning blade, and reusing the collected transfer residual toner. Preferably used.
[0140]
Next, the toner image on the transfer material 6 is fixed by a heat and pressure fixing unit. As the heating and pressing fixing means, a heating roller with a built-in heating element such as a halogen heater and an elastic pressing roller pressed against the heating roller with a pressing force as a basic configuration, or a heating roller through a film. A method of heating and fixing (FIGS. 5 and 6) can be cited, but the toner of the present invention is excellent in fixing property and anti-offset property, and thus shows good matching with the heating and pressing fixing means as described above.
[0141]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.
[0142]
(Production Example of Toner and Comparative Production Example)
Production examples of the toner of the present invention and comparative production examples will be described.
[0143]
Production Example 1 of Toner
650 g of ion-exchanged water and 0.1 mol / l-Na were placed in a 2-liter four-necked flask equipped with a high-speed stirrer TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.).₃  PO₄  500 g of the aqueous solution was charged, the rotation speed was adjusted to 12000 rpm, and the mixture was heated to 70 ° C. Here 1 mol / l-CaCl₂  70 parts by weight of an aqueous solution is gradually added, and fine minute water-insoluble dispersion stabilizer Ca is added.₃  (PO₄  )₂  The aqueous dispersion medium containing was prepared.
[0144]
On the other hand, as a dispersoid,

[0145]
After dispersing the above mixture using an attritor (manufactured by Mitsui Kinzoku Co., Ltd.) for 3 hours, 5 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to prepare a polymerizable monomer composition. did.
[0146]
Next, the polymerizable monomer composition was charged into the aqueous dispersion medium, and N 2 at an internal temperature of 70 ° C.₂  Under an atmosphere, the mixture was stirred for 15 minutes while maintaining the rotation speed of the high-speed stirrer at 12,000 rpm to granulate the polymerizable monomer composition. Thereafter, the stirring was changed to a propeller stirring blade, and the mixture was maintained at the same temperature for 10 hours while stirring at 50 rpm to complete the polymerization.
[0147]
After completion of the polymerization, the suspension was cooled, and then dilute hydrochloric acid was added to remove the dispersion stabilizer. Further, after washing with water is repeated several times and drying is performed, the surface treatment of the polymer particles is performed by using a powder processing apparatus system having four stages of rotating rotors having ten blades shown in FIG. Was. At this time, the rotation speed of the rotating rotor of the powder processing system was 7900 rpm (peripheral speed of the outermost edge: 100 m / sec), the processing amount of the polymer particles was 10 kg / hr, and the atmosphere temperature during the processing was 35 ° C. And
[0148]
The obtained polymer particles (A) have a circle-equivalent number average diameter of 4.9 μm, an average circularity of 0.989, and a coarse particle content of more than 10 μm in the circle equivalent content of 1.7% by number. The average circularity of the coarse particles was 0.965, the peak molecular weight by GPC was 16,000, and the Mw / Mn was 35.
[0149]
100 parts by weight of the polymer particles (A) and hydrophobic oil-treated silica fine powder (BET; 200 m²  / G) 2 parts by weight were dry-mixed with a Henschel mixer to obtain the toner (A) of the present invention, and then 6 parts by weight of the toner (A) and 94 parts by weight of a resin-coated magnetic ferrite carrier (average particle size: 45 μm) Were mixed to prepare a two-component developer (A) for magnetic brush development.
[0150]
The obtained toner (A) had the same particle size distribution and shape distribution as the polymer particles (A). Further, when the dispersion state of the wax component in the toner (A) was observed by TEM, as shown in the schematic view of FIG. Was. At this time, r / R was 0.61.
[0151]
Production Examples 2 to 4 of Toner
The particle size and shape of the polymer particles were controlled by adjusting the preparation conditions of the aqueous dispersion medium, the number of rotations of the rotating rotor of the powder processing apparatus system, the throughput of the polymer particles, and the ambient temperature during the treatment. Except for the above, after obtaining polymer particles (B) to (D) in the same manner as in Production Example 1 of the toner, the toners (B) to (D) and the developers (B) to (D) were Prepared.
[0152]
Comparative Production Example 1 of Toner

[0153]
The above mixture was melt-kneaded with a twin-screw extruder, and the cooled kneaded material was coarsely pulverized with a hammer mill, and the coarsely pulverized material was finely pulverized with a jet mill. After mixing with a mixer, the obtained mixed powder was put into a container containing water, and further dispersed in water using a homomixer. The temperature of the water was gradually increased, and the mixture was heated at 60 ° C. for 2 hours. Thereafter, diluted hydrochloric acid was added to the container to sufficiently dissolve the calcium phosphate on the surface of the finely pulverized product particles. This was filtered, washed and dried, then passed through a 400-mesh sieve to remove aggregates, and then classified to obtain a classified powder (a). Comparative toner (a) and comparative developer (a) were prepared in the same manner as in Example 1 using the classified powder (a).
[0154]
The wax component in the comparative toner (a) was contained in a finely dispersed state. At that time, r / R was 0.01 or less.
[0155]
Comparative Production Example 2 of Toner
After obtaining the classified powder (b) in the same manner as in Comparative Production Example 1 of the toner except that the particle size and the shape of the classified powder were controlled by changing the conditions of the pulverization and the powder processing system, Toner (b) and a comparative developer (b) were prepared.
[0156]
Production Example 5 of Toner
Except for using a modified polypropylene wax (melting point = 105 ° C.) in place of the ester wax and adjusting the stirring conditions during granulation and the processing conditions of the powder processing apparatus system, the weight was changed in the same manner as in Production Example 1 of the toner described above. After obtaining the coalesced particles (E), the toner (E) and the developer (E) were prepared.
[0157]
Comparative Production Example 3 of Toner
After obtaining polymer particles (c) in the same manner as in Production Example 5 of the toner except that the powder processing system is not used, the comparative toner (c) and the comparative developer ( c) was adjusted.
[0158]
Table 1 shows various properties of the toners (A) to (E) obtained above and comparative toners (a) to (c).
[0159]
[Table 1]

[0160]
(Examples, Reference Examples, and Comparative Examples)
Examples 1-2, Reference Examples 1-3, and Comparative Examples 1-3
An image forming apparatus used in this embodiment will be described. 1 and 2 are a schematic explanatory view of a cross section of an image forming apparatus applied to the present embodiment and an enlarged cross-sectional view of a main part of a developing device for a two-component developer.
[0161]
The photoreceptor drum 1 has a photosensitive layer 1b having an organic optical semiconductor on a base material 1a, and is exposed to light by a charging roller 2 (conductive elastic layer 2a, core metal 2b) which rotates in the direction of the arrow and rotates in contact with each other. The surface drum 1 is charged to a surface potential of about -600V. The exposure 3 is turned on and off on the photoreceptor by a polygon mirror according to digital image information, thereby forming an electrostatic image having an exposure portion potential of -100 V and a dark portion potential of -600 V. When a full-color image is formed, a plurality of developing units 4-1, 4-2, 4-3, and 4-4 are used to invert a yellow toner, a magenta toner, a cyan toner, or a black toner on the photoreceptor 1 by a reversal developing method. To obtain a toner image. The toner image is transferred onto the intermediate transfer member 5 (elastic layer 5a, core metal 5b as a support), and a four-color superimposed developed image is formed on the intermediate transfer member 5. The transfer residual toner on the photoreceptor 1 is collected in a residual toner container 9 by a cleaner member 8.
[0162]
The intermediate transfer member 5 was formed by coating a pipe-shaped core metal 5b with an elastic layer 5b in which a carbon black conducting member was sufficiently dispersed in nitrile-butadiene rubber (NBR). The hardness of the coat layer 5b is 30 degrees according to “JIS K-6301” and the volume resistivity is 10%.⁹  Ω · cm. The transfer current required for transfer from the photoreceptor 1 to the intermediate transfer member 5 was about 5 μA, which was obtained by applying +500 V from the power supply to the cored bar 5b.
[0163]
Coat a core metal 7b having an outer diameter of 20 mm and a diameter of 10 mm of the transfer roller 7 with a carbon conductive material sufficiently dispersed in an ethylene-propylene-diene-based terpolymer (EPDM) foam. The elastic layer 7a thus generated has a volume resistivity of 10⁶  A standard hardness according to “JIS K-6301” having a value of 35 degrees in Ω · cm was used. A voltage was applied to the transfer roller to flow a transfer current of 15 μA.
[0164]
As the heat fixing device H, a heat roll type fixing device having no oil application function was used. At this time, both the upper roller and the lower roller had a surface layer made of a fluororesin, and the diameter of the roller was 60 mm. The fixing temperature was set at 160 ° C. and the nip width was set at 7 mm.
[0165]
Under the above setting conditions, a continuous mode (mode in which the consumption of toner is promoted without stopping the developing device) in a single color continuous mode is performed at a printout speed of 12 sheets per minute (A4 size) at normal temperature and normal humidity. A printout test of 1,000 sheets was performed in an environment of 25 ° C./60% RH, and then a printout test of 9000 sheets was performed in an environment of high temperature and high humidity (30 ° C./80% RH). During the printout test, the toners (A) to (E) and the comparative developers (a) to (c) were successively supplied. The obtained printout image and the image forming apparatus after the printout test were observed, and items described below were evaluated.
[0166]
Table 2 shows the above evaluation results.
[0167]
[Table 2]

[0168]
Example 3 and Comparative Example 4
In this embodiment, a commercially available laser beam printer LBP-EX (manufactured by Canon Inc.) was remodeled with a reuse mechanism attached, reconfigured, and used. That is, in FIG. 4, after the untransferred toner on the photosensitive drum 40 is scraped off by the elastic blade 42 of the cleaner 41 in contact with the photosensitive drum, the toner is sent into the cleaner by the cleaner roller, and further passed through the cleaner screw 43. Then, the toner was returned to the developing device 46 via the hopper 45 by the supply pipe 44 provided with the conveying screw, and a system utilizing the recovered toner was attached again. As the primary charging roller 47, the conductive carbon coated with the nylon resin was dispersed. Using a rubber roller (diameter: 12 mm, contact pressure: 50 g / cm), the electrostatic latent image carrier was exposed to laser light (600 dpi) to obtain dark area potential V._D= -700V, bright part potential V_L= -200V. A developing sleeve 48 having a surface roughness Ra of 1.1 coated with a resin in which carbon black is dispersed on the surface as a toner carrier is set to be 1.1 times the moving speed of the photosensitive drum surface, Next, the gap between the photosensitive drum and the developing sleeve (between SD) was set to 270 μm, and a urethane rubber blade was used as a toner regulating member in contact therewith. An AC bias component was superimposed on a DC bias component and used as a developing bias. The fixing device shown in FIGS. 5 and 6 is used as the heat fixing device H. The surface temperature of the temperature detecting element 31d of the heating member 31 is 130 ° C., and the heating member 21 is made of a sponge having a silicone rubber foam as a lower layer. The total pressure between the pressure rollers 33 is 10 kg, the nip between the pressure rollers and the film is 7 mm, and the fixing film 32 has a low resistance in which a conductive material is dispersed in PTEF (high molecular weight type) on a contact surface with a transfer material. A heat-resistant polyimide film having a thickness of 50 μm and having a release layer was used.
[0169]
Under the above setting conditions, the toner (A) is printed at a printout speed of 12 sheets (A4 size) / min in an environment of normal temperature and normal humidity (25 ° C., 60% RH) and high temperature and high humidity (30 ° C., 80% RH). And the comparison toner (a) in the intermittent mode (that is, a mode in which the developing unit is paused for 10 seconds each time one sheet is printed out and the deterioration of the toner is promoted by the preliminary operation at the time of restart) while each of the comparison toners (a) is sequentially supplied. A printout test for 5000 sheets was performed, and the printout images obtained were evaluated for the items described below.
[0170]
Further, the matching between the image forming apparatus used at the same time and the toner was also evaluated.
[0171]
Table 3 shows the above evaluation results.
[0172]
[Table 3]

[0175]
Examples of the present invention and evaluation items described in comparative examples and evaluation criteria thereof will be described.
[0176]
(Printout image evaluation)
<1> Image density
Plain paper for ordinary copiers (75 g / m²  The evaluation was performed by maintaining the image density when a predetermined number of printouts were completed. The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth) with respect to the printout image of a white background portion having a document density of 0.00.
A: 1.40 or more
B: 1.35 or more and less than 1.40
C: 1.00 or more and less than 1.35
D: less than 1.00
[0177]
<2> Image fog
The fog density (%) is determined from the difference between the whiteness of the white background portion measured by a “Reflectometer” (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness of the transfer paper using the printout image after the predetermined number of printouts are completed. Calculated and evaluated for image fog.
A: less than 1.5%
B: 1.5% or more and less than 2.5%
C: 2.5% or more and less than 4.0%
D: 4.0% or more
[0178]
<3> Image scattering
After a predetermined number of printouts are completed, the “den” character pattern shown in FIG.²  ) And cardboard (105g / m²  And 135g / m²  9) was visually evaluated for toner scattering to the periphery of the character when printed (state of FIG. 9B).
A: Almost no occurrence.
B: Slight scattering is observed.
C: Slight scattering is observed.
D: Remarkable scattering is observed.
[0179]
<4> Missing image
After a predetermined number of printouts are completed, the “surprise” character pattern shown in FIG.²  ) Were visually evaluated for missing characters (the state shown in FIG. 10B).
A: Almost no occurrence.
B: Slight hollowing is observed.
C: A slight hollow is seen.
D: A noticeable hollow is observed.
[0180]
<5> dot reproducibility
After a predetermined number of printouts are completed, the checker pattern shown in FIG.²  ) And cardboard (105g / m²  ) And the dot reproducibility was evaluated.
A: 2 or less missing / 100
B: 3-5 defects / 100 defects
C: 6-10 defects / 100 defects
D: 11 or more missing / 100
[0181]
(Evaluation of image forming device matching)
<1> Matching with developing sleeve
After completion of the printout test, the state of fixation of the residual toner on the surface of the developing sleeve and the effect on the printout image were visually evaluated.
A: Not generated.
B: Almost no occurrence.
C: There is sticking, but there is little effect on the image.
D: Many adhesions cause image unevenness.
[0182]
<2> Matching with photosensitive drum
After the completion of the printout test, the occurrence of scratches on the surface of the photosensitive drum and adhesion of residual toner and the effect on the printout image were visually evaluated.
A: Not generated.
B: Slight scratching is observed, but there is no effect on the image.
C: There is sticking or damage, but there is little effect on the image.
D: A lot of sticking occurs, causing vertical streak-like image defects.
[0183]
<3> Matching with intermediate transfer member
After the completion of the printout test, the surface of the intermediate transfer member was visually evaluated for scratches and the state of fixation of the residual toner.
A: Not generated
B: The presence of residual toner on the surface is recognized, but there is no effect on the image.
C: There is sticking or damage, but there is little effect on the image.
D: Many adhesions cause image defects.
[0184]
<4> Matching with fixing device
After completion of the printout test, scratches on the surface of the fixing film and the state of fixation of the residual toner were visually evaluated.
A: Not generated
B: Slight adhesion is observed, but there is no effect on the image.
C: There is sticking or damage, but there is little effect on the image.
D: Many adhesions cause image defects.
[0185]
【The invention's effect】
As described above, according to the present invention, by precisely controlling the particle shape distribution of the toner particles, it is possible to impart desirable developability and transferability to the toner. That is, the average diameter is 2 to 8 μm, The average circularity is 0.960 to 0.995Wherein the toner has a coarse particle diameter of more than 10 μm3%, And the average circularity of the coarse particles is0.930~0.975By doing so, the durability of the toner is prevented from deteriorating, and it is possible to form a high-quality image with excellent environmental stability over a long period of time. Further, matching with the image forming apparatus is also preferable.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view of an image forming apparatus suitable for the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of a developing device for a two-component developer.
FIG. 3 is an enlarged cross-sectional view of a main part of a developing device for a one-component developer.
FIG. 4 is a schematic diagram illustrating an image forming apparatus that reuses untransferred toner.
FIG. 5 is an exploded perspective view of a main part of the fixing device used in the embodiment of the present invention.
FIG. 6 is an enlarged cross-sectional view of a main part showing a film state when the fixing device used in the embodiment of the present invention is not driven.
FIG. 7 is a schematic diagram illustrating an example of a cross section of toner particles including a wax component.
FIG. 8 is an explanatory diagram of a checker pattern for checking development characteristics of toner.
FIG. 9 is a schematic diagram showing a state where a character image is hollow;
FIG. 10 is a schematic diagram showing a state in which a character image is scattered.
FIG. 11 is a schematic external view of a powder processing apparatus system suitable for the present invention.
FIG. 12 is a partial sectional view of a main part of a powder processing apparatus suitable for the present invention.
FIG. 13 is a perspective view of a rotating rotor of a powder processing apparatus suitable for the present invention.
[Explanation of symbols]
1. Photoconductor (electrostatic latent image carrier)
2 Charging roller
3 Exposure
4. Four-color developing unit (4-1, 4-2, 4-3, 4-4)
5 Intermediate transfer member
6 Transfer material
7 Transfer roller
11 Developer carrier
13 Photoconductor drum
30 Stay
31 heating element
31a Heater substrate
31b Heating element
31c Surface protective layer
31d temperature detector
32 Fixing film
33 Pressure roller
34 coil spring
35 Film edge regulation flange
36 Power supply connector
37 Disconnection member
38 Entrance Guide
39 Exit guide (separation guide)

Claims (30)

At least, a dry toner having toner particles containing a binder resin, a colorant and a wax component, and in a number-based circle equivalent diameter-circularity scattergram measured by a flow-type particle image measuring device of the toner, The toner has a circle equivalent number average diameter D1 of 2 to 8 μm , an average circularity of 0.960 to 0.995 , and the toner contains 0.02 to 3 % by number of coarse particles having a circle equivalent diameter exceeding 10 μm. Wherein the coarse particles have an average circularity of 0.930 to 0.975 . 2. The dry toner according to claim 1, wherein the toner has a circle-equivalent number average diameter D1 of 2 to 5 [mu] m . In the tomographic observation of the toner particles using a transmission electron microscope (TEM) of the toner, 0.9 ≦ R Twenty cross-sectional layers of toner particles exhibiting a major diameter R satisfying the relationship of /D4≦1.1 are selected, and the largest major axis r of the phase separation structures caused by the wax component present on the tomographic plane of the toner particles is selected. Is measured for the tomographic plane of each toner particle, and the obtained arithmetic mean value of r / R satisfies the arithmetic mean value of 0.05 ≦ r / R ≦ 0.95, and the wax component is bound. The dry toner according to claim 1, wherein the toner is dispersed in a resin in a substantially spherical and / or spindle-shaped island shape. The arithmetic mean value of the r / R satisfies the arithmetic mean value of 0.25 ≦ r / R ≦ 0.90, and the wax component is substantially spherical and / or spindle-shaped in the binder resin. 4. The dry toner according to claim 1, wherein the dry toner is dispersed in a toner. At least a charging step of externally applying a voltage to a charging member to charge the electrostatic latent image carrier, a latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier, A developing step of developing the charge image with toner to form a toner image on the electrostatic latent image carrier, a transfer step of transferring the toner image on the electrostatic latent image carrier to a transfer material, and a toner on the transfer material A fixing step of heating and fixing the image, wherein the toner is a dry toner having toner particles containing at least a binder resin, a colorant and a wax component, and a flow type particle image of the toner. In the number-based circle equivalent diameter-circularity scattergram measured by the measurement device, the circle-equivalent number average diameter D1 of the toner is 2 to 8 μm , the average circularity is 0.960 to 0.995 , and the toner is Equivalent to a circle exceeding 10 μm And it contains 0.02 to 3% by number of coarse particles having an image forming method, wherein the average circularity of the coarse particles is from 0.930 to 0.975. 6. The image forming method according to claim 5, wherein the toner has a circle-equivalent number average diameter D1 of 2 to 5 [mu] m . In the tomographic observation of the toner particles using a transmission electron microscope (TEM) of the toner, 0.9 ≦ R Twenty cross-sectional layers of toner particles exhibiting a major diameter R satisfying the relationship of /D4≦1.1 are selected, and the largest major axis r of the phase separation structures caused by the wax component present on the tomographic plane of the toner particles is selected. Is measured for the tomographic plane of each toner particle, and the obtained arithmetic mean value of r / R satisfies the arithmetic mean value of 0.05 ≦ r / R ≦ 0.95, and the wax component is bound. The image forming method according to claim 5, wherein the resin is dispersed in a resin in a substantially spherical and / or spindle-shaped island shape. The arithmetic mean value of r / R of the toner satisfies the arithmetic mean value of 0.25 ≦ r / R ≦ 0.90, and the wax component is substantially spherical and / or spindle-shaped in the binder resin. The image forming method according to claim 5, wherein the image is dispersed in an island shape. In the developing step, the moving speed of the toner carrier surface in the developing region is 1.5 to 3.0 times the moving speed of the electrostatic latent image carrier, and the surface roughness Ra of the toner carrier is The image forming method according to claim 5, wherein (μm) is 1.5 or less. 10. The image forming method according to claim 5, wherein a ferromagnetic metal blade is opposed to the toner carrier at a small interval. 10. The image forming method according to claim 5, wherein a blade made of an elastic material is opposed to and abuts on the toner carrier. 12. The image forming method according to claim 5, wherein the electrostatic latent image carrier and the toner carrier have a certain interval, and are developed while applying an alternating electric field. 13. The method according to claim 5, wherein in the charging step, the charging member is brought into contact with the electrostatic latent image carrier, and a voltage is externally applied to the charging member to charge the electrostatic latent image carrier. An image forming method according to any one of the above. In a transfer step of electrostatically transferring the toner image on the electrostatic latent image carrier to a transfer material using a transfer device, it is determined that the electrostatic latent image carrier and the transfer device are in contact with each other via the transfer material. An image forming method according to any one of claims 5 to 13, wherein: 15. The method according to claim 5, wherein in the heat fixing step, the toner image is heat-fixed to the transfer material by a heat fixing device which does not supply an offset preventing liquid or does not have a fixing device cleaner. 2. The image forming method according to 1., In the heat-fixing step, the toner image is heat-fixed to the transfer material by a fixedly supported heating body and a pressing member which is in opposition and pressure contact with the heating body and closely adheres to the heating body via a film. The image forming method according to any one of claims 5 to 15, wherein: 6. A toner reuse mechanism for cleaning and recovering untransferred residual toner on the electrostatic latent image carrier after the transfer step, and using the recovered toner again for development in the development step. 17. The image forming method according to any one of the above items. At least a charging step of externally applying a voltage to a charging member to charge the electrostatic latent image carrier, a latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier, A developing step of developing the charge image with toner to form a toner image on the electrostatic latent image carrier, a first transfer step of transferring the toner image on the electrostatic latent image carrier to the intermediate transfer body, In an image forming method including a second transfer step of transferring a toner image on an intermediate transfer member to a transfer material and a fixing step of heating and fixing the toner image on the transfer material, the toner includes at least a binder resin, A dry toner having toner particles containing a colorant and a wax component, wherein the number of circles corresponding to the number of circles of the toner in a number-based circle equivalent diameter-circularity scattergram measured by a flow-type particle image measuring device of the toner. the average diameter D1 is 2~8μm, average Katachido is 0.960 to 0.995, the toner has circularly contains 0.02 to 3% by number of coarse particles having a equivalent diameter exceeding 10 [mu] m, an average circularity of the coarse particles is 0.930 To 0.975 . 19. The image forming method according to claim 18, wherein the circle-equivalent number average diameter D1 of the toner is 2 to 5 [mu] m . In the tomographic observation of the toner particles using a transmission electron microscope (TEM) of the toner, 0.9 ≦ R Twenty tomographic planes of the toner particles exhibiting the major axis R satisfying the relationship of /D4≦1.1 are selected, and the major axis r of the largest phase separation structure due to the wax component present in the tomographic plane of the toner particles is selected. Is measured for the tomographic plane of each toner particle, and the obtained arithmetic mean value of r / R satisfies the arithmetic mean value of 0.05 ≦ r / R ≦ 0.95, and the wax component is bound. 20. The image forming method according to claim 18, wherein the resin is dispersed in a resin in a substantially spherical and / or spindle-shaped island shape. The arithmetic mean value of r / R of the toner satisfies the arithmetic mean value of 0.25 ≦ r / R ≦ 0.90, and the wax component is substantially spherical and / or spindle-shaped in the binder resin. The image forming method according to any one of claims 18 to 20, wherein the image is dispersed in an island shape. In the developing step, the moving speed of the toner carrier surface in the developing region is 1.05 to 3.0 times the moving speed of the electrostatic latent image carrier, and the surface roughness Ra of the toner carrier is 22. The image forming method according to claim 18, wherein (μm) is 1.5 or less. 23. The image forming method according to claim 18, wherein a ferromagnetic metal blade is opposed to the toner carrier at a small interval. 23. The image forming method according to claim 18, wherein a blade made of an elastic material is opposed to and brought into contact with the toner carrier. The image forming method according to any one of claims 18 to 24, wherein the electrostatic latent image carrier and the toner carrier have a certain interval, and are developed while applying an alternating electric field. 26. The method according to claim 18, wherein in the charging step, the charging member is brought into contact with the electrostatic latent image carrier, and a voltage is applied to the charging member from outside to charge the electrostatic latent image carrier. An image forming method according to any one of the above. In a transfer step of electrostatically transferring the toner image on the electrostatic latent image carrier to a transfer material using a transfer device, it is determined that the electrostatic latent image carrier and the transfer device are in contact with each other via the transfer material. The image forming method according to any one of claims 18 to 26, wherein: 28. The method according to claim 18, wherein in the heat fixing step, the toner image is heat-fixed to the transfer material by a heat fixing device having no supply of an offset preventing liquid or having no fixing device cleaner. 2. The image forming method according to 1., In the heat-fixing step, the toner image is heat-fixed to the transfer material by a fixedly supported heating body and a pressing member which is in opposition and pressure contact with the heating body and closely adheres to the heating body via a film. The image forming method according to any one of claims 18 to 28, wherein: It has a toner reuse mechanism for cleaning and collecting the untransferred residual toner on the electrostatic latent image carrier after the first transfer step, and using the collected toner again in the developing step. The image forming method according to any one of claims 18 to 29.

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