JP3652425B2 - Toner manufacturing method and electrophotographic apparatus - Google Patents

Description

【００６９】
表２は本実施例で結着樹脂として使用するスチレンアクリル酸ブチル共重合体の熱特性を示している。
【００７０】
【表２】

【００７１】
表２において、ＴｇＬ（℃）は低分子量重合体成分のガラス転移点、ＭｗＬは低分子量重合体成分の重量平均分子量、ＴｇＨ（℃）は高分子量重合体成分のガラス転移点、ＭｗＨは高分子量重合体成分の重量平均分子量、ＫＬ／Ｈは低分子量重合体成分と高分子量重合体成分の組成比、Ｔｓｐ（℃）は重合体全体の軟化点である。
【００７２】
表３は図１に示した混練装置（具体的には池貝鉄工社製ＰＣＭ４３）における各混練セグメントの設定温度と、吐出温度を示している。なお、材料の供給量は４０ｋｇ／ｈ、混練軸の回転における周速度は６００ｍｍ／sである。
【００７３】
【表３】

【００７４】
表４は本実施例で使用した低動摩擦係数材料の動摩擦係数を示している。
【００７５】
【表４】

【００７６】
表５は本実施例で製造したトナーサンプルのサンプル番号、使用した結着樹脂、混練条件、低動摩擦係数材料を示している。
【００７７】
【表５】

【００７８】
表６は本実施例で製造したトナーサンプルを用い、電子写真複写機ＦＰ−４０８０（松下電器社製、商品名）改造機にて画像形成を行い、得られた画像の画像評価と定着性評価を行った結果である。現像は二成分方式で、キャリアはシリコン樹脂コートしたＣｕ−Ｚｎ−Ｆｅ2Ｏ3を使用した。定着評価はプロセス速度を１４０ｍｍ／s（低速）での高温オフセット性と、４５０ｍｍ／s（高速）での定着率により評価した。定着率は画像濃度１．０±０．２のパッチを各列毎に、「ベンコット」（旭化成社製、商品名）を巻いた５００ｇ（φ３６ｍｍ）の錘で１０往復擦過し、擦過前後の画像濃度をマクベス反射濃度計にて測定し、その変化率により定義した。この定着率は７５％以上を合格レベルにした。また、オフセット性は１８０℃以上を合格レベルにした。
【００７９】
画像評価は画像形成の初期と２０万枚後の耐久テスト後の画像濃度と地かぶりに評価した。地かぶりは明視にて判断し、実用上問題ないレベルであれば合格（○）とした。
【００８０】
【表６】

【００８１】
表６から分かるように、トナーサンプルＡ１、Ａ２、Ａ３、Ａ４（実施例トナー）は低速度での高温オフセット性、高速度での定着率、画像濃度、地かぶりも良好な特性を示した。しかしトナーサンプルＢ１（比較例トナー）では高速度での定着率が低く、分散不良に起因すると思われる地かぶりが増大した。トナーサンプルＢ２（比較例トナー）ではオフセット性が悪く、分散不良に起因すると思われる地かぶりが増大した。
【００８２】
（実施例２）
表７は本実施例で製造したトナーサンプルＡ５の処方である。ここでは結着樹脂として実施例１で使用したスチレンアクリル酸ブチル共重合体（Ｒ−Ａ）を用い、混練条件は実施例１のＮ−１にした。
【００８３】
【表７】

【００８４】
図１１は本実施例で使用した現像方式が磁性一成分現像方式の電子写真装置の構成を示す断面図である。図において、２０１は有機感光体で、アルミニウムの導電性支持体上にポリビニルブチラール樹脂（積水化学製エレックＢＬ−１）にτ型無金属フタロシアニン（東洋インキ製）の電荷発生物質を分散した電荷発生層と、ポリカーボネート樹脂（三菱ガス化学製Ｚ−２００）と、１、１−ビス（Ｐ−ジエチルアミノフェニル）−４、４−ジフェニル−１、３−ブタジエン（アナン＝製Ｔ−４０５）を含む電荷輸送層を順次積層した構成のものである。２０２は感光体２０１と同軸で固定された磁石、２０３は感光体をマイナスに帯電するコロナ帯電器、２０４は感光体の帯電電位を制御するグリッド電極、２０５は信号光である。
【００８５】
２０７は磁性一成分トナー、２０６は感光体２０１表面に磁性トナー２０７を供給するトナーホッパー、２０８は感光体２０１とギャップを開けて設定した非磁性電極ローラ、２０９は電極ローラ２０８の内部に設置された磁石、２１０は電極ローラ２０８に電圧を印加する交流高圧電源、２１１は電極ローラ上のトナーをかきおとすポリエステルフィルム製のスクレーパ、２１２はトナーホッパー内でのトナーの流れをスムーズにし、またトナーが自重で押しつぶされ感光体と電極ローラとの間でのつまりが発生するのを防止するためのダンパーである。これらにより露光後の潜像を可視像化するための現像装置が構成される。ここで、電極ローラ２０８は非画像部の余分なトナーを回収するためのものである。
【００８６】
２１３は感光体上のトナー像を紙に転写する転写ローラで、その表面が感光体２０１の表面に接触するように設定されている。転写ローラ２１３は導電性の金属からなる軸の周囲に導電性弾性部材を設けた弾性ローラである。感光体２０１への押圧力は転写ローラ２１３一本（約２１６ｍｍ）当たり０〜２０００ｇ、望ましくは５００〜１０００ｇである。これは転写ローラ２１３を感光体２０１に圧接するためのバネのバネ係数と縮み量の積から測定した。感光体２０１との接触幅は約０．５ｍｍ〜５ｍｍである。転写ローラ２１３のゴム硬度はアスカーＣの測定法（ローラ形状でなく、ブロック片を用いた測定）で８０度以下で、望ましくは３０〜４０度である。弾性ローラ２１３は直径６ｍｍのシャフトの周辺にＬｉ₂Ｏ 等のリチウム塩を内添することによりを抵抗値を１０⁷Ω（軸と表面に電極を設け、両者に５００Ｖ印加する）にした発泡性のウレタンエラストマーを用いた。転写ローラ２１３全体の外径は１６．４ｍｍで、硬度はアスカーＣで４０度であった。転写ローラ２１３を感光体２０１に転写ローラ２１３の軸を金属バネで押圧する事で接触させた。押圧力は約１０００ｇであった。ローラの弾性体としては前記発泡性のウレタンのエラストマーの他にＣＲゴム、ＮＢＲ、Ｓｉゴム、フッ素ゴム等の他の材料からなる弾性体を使用することもできる。そして導電性を付与するための導電性付与剤としては前記リチウム塩の他にカーボンブラック等の他の導電性物質を使用することもできる。
【００８７】
２１４は転写紙を転写ローラ２１３に導入する導電性部材からなる突入ガイド、２１５は導電性部材の表面を絶縁被覆した搬送ガイドである。突入ガイド２１４と搬送ガイド２１５は直接あるいは抵抗を介して接地している。２１６は転写紙、２１７は転写ローラ２１３に電圧印加する電圧発生電源である。
【００８８】
２１８は転写残りのトナーをかき落とすクリーニングブレード、２１９は廃トナーを貯めるクリーニングボックス、２２３は廃トナーである。
【００８９】
クリーニングブレードに弾性体ウレタンブレードを用いたが、バイアス印可したファーブラシや、導電性金属ローラでも同様の結果となる。
【００９０】
感光体２０１表面での磁束密度は６００Ｇｓである。電極ローラ内部の磁力の方を強くして搬送性を向上させた。また図中に示す磁石２０２の磁極角はθは１５度に設定した。感光体２０１の直径は３０ｍｍで、周速２６０ｍｍ／ｓで図中の矢印の方向に回転させ用いた。電極ローラ２０８の直径は１６ｍｍで、周速４０ｍｍ／ｓで感光体２０１の進行方向とは逆方向（図中の矢印方向）に回転させ用いた。感光体２０１と電極ローラ２０８とのギャップは３００μｍに設定した。
【００９１】
感光体２０１をコロナ帯電器２０３（印加電圧−４．５ｋＶ、グリッド２０４の電圧−５００Ｖ）で、ー５００Ｖに帯電させた。この感光体２０１にレーザ光２０５を照射し静電潜像を形成した。このとき感光体２０１の露光電位はー９０Ｖであった。この感光体２０１表面上に、トナー２０７をトナーホッパー２０６内で磁石により付着させた。次に感光体２０１を電極ローラ２０８の前を通過させた。感光体２０１の未帯電域の通過時には、電極ローラ２０８には交流高圧電源２１０により、０Ｖの直流電圧を重畳した７５０Ｖ0-p（ピーク・ツー・ピーク １．５ｋＶ）の交流電圧（周波数１ｋＨｚ）を印加した。その後、−５００Ｖに帯電し静電潜像が書き込まれた感光体２０１の通過時には、電極ローラ２０８には交流高圧電源２１０により、ー３５０Ｖの直流電圧を重畳した７５０Ｖ0-p（ピーク・ツー・ピーク １．５ｋＶ）の交流電圧（周波数１ｋＨｚ）を印加した。すると感光体２０１の帯電部分に付着したトナーは電極ローラ２０８に回収され、感光体２０１上には画像部のみのネガポジ反転したトナー像が残った。矢印方向に回転する電極ローラ２０８に付着したトナーは、スクレーパ２１１によってかきとり、再びトナーホッパー２０６内に戻し次の像形成に用いた。こうして感光体２０１上に得られたトナー像を、転写紙に、転写ローラ２１３によって転写した後、定着器（図示せず）により熱定着して複写画像が得られる。
【００９２】
かかる電子写真装置により、前記トナーサンプルＡ５を用いて画像出しを行ったところ、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で、濃度が１．４の１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像を得ることができた。画像濃度１．４以上の高濃度の画像が得られた。非画像部での地かぶりも発生していなかった。更に、１００００枚の長期複写テストを行ったところ、スクレーパへのトナーの固着はなく、また感光体表面へのトナー（離型剤）のフィルミングはなく、初期の画像に比べて遜色のない高濃度、低地カブリの複写画像が得られた。
【００９３】
（実施例３）
表８は本実施例で製造したトナーサンプルＡ６の処方である。ここでは結着樹脂として実施例１で使用したスチレンアクリル酸ブチル共重合体（Ｒ−Ｂ）を用い、混練条件は実施例１のＮ−２にした。
【００９４】
【表８】

【００９５】
このサンプルトナーＡ６を用いて、前記実施例２で使用した図１１に示した電子写真装置により画像出しを行ったところ、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で濃度が１．４の１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像が得られた。画像濃度１．４以上の高濃度の画像が得られた。非画像部の地かぶりも発生していなかった。更に、１００００枚の長期複写テストを行ったところ、スクレーパへのトナーの固着はなく、また感光体表面へのトナー（離型剤）のフィルミングはなく、初期の画像に比べて遜色のない高濃度、低地カブリの複写画像が得られた。
【００９６】
（実施例４）
図１２は本実施例で使用した電子写真装置の構成を示す断面図である。本実施例装置は、前記実施例１の図１１に示した電子写真装置の構成に、廃トナーリサイクル機構を付加した構成である。すなわち、転写残りのトナーをクリーニングブレード２１８でかき落とし、クリーニングボックス２１９に一時的に貯められた廃トナー２２３が、輸送管２２０によって、現像装置のトナーホッパ２０６に戻されるよう構成されている。
【００９７】
実施例２で製造したトナーサンプルＡ５を用いて、かかる電子写真装置により画像出しを行った。その結果、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で濃度が１．４の１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像が得られた。画像濃度１．４以上の高濃度の画像が得られた。非画像部の地かぶりも発生していなかった。更に、廃トナーリサイクルを行いながら、１００００枚の長期複写テストを行ったところ、１００００枚後のトナ−の流動性の低下はなく、高い電荷量を維持し、感光体へのトナー（離型剤）のフィルミングは発生なく、初期の画像に比べて遜色のない高濃度、低地カブリの複写画像が得られた。トナーのリサイクルも良好に行えた。
【００９８】
（実施例５）
前記実施例４の図１２に示した電子写真装置により、実施例３で示したトナーＡ６を用いて画像出しを行った。その結果、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で濃度が１．４の１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像が得られた。画像濃度１．４以上の高濃度の画像が得られた。非画像部の地かぶりも発生していなかった。更に、廃トナーリサイクルを行いながら、１００００枚の長期複写テストを行ったところ、１００００枚後のトナ−の流動性の低下はなく、高い電荷量を維持し、感光体へのトナー（離型剤）のフィルミングは発生なく、初期の画像に比べて遜色のない高濃度、低地カブリの複写画像が得られた。トナーのリサイクルも良好に行えた。
【００９９】
以上の実施例２〜５ではプロセス速度を２６０ｍｍ／sにして画像形成を行ったが、プロセス速度を１４０ｍｍ／s、４５０ｍｍ／sにしても同様な良好な結果を得ることができた。
【０１００】
（実施例６）
表９は本実施例で製造したトナーサンプルの処方である。
【０１０１】
【表９】

【０１０２】
ここでは結着樹脂として実施例１で使用したスチレンアクリル酸ブチル共重合体（Ｒ−Ａ）を用い、混練条件は実施例１のＮ−１にし、イエロートナーのイエロー着色剤としてベンジジン系黄色顔料を５重量部、マゼンタトナーのマゼンタ着色剤としてナフロール系不溶性アゾ顔料６重量部、シアントナーのシアン着色剤として銅フタロシアニン顔料を５重量部用いた。また、電荷制御剤として酸価２０のポリエステル樹脂を２０重量部添加した。なお、電荷制御座としてのポリエステル樹脂は酸価が５〜４０の範囲のものを使用するのが好ましく、結着樹脂１００重量部に対して５〜４５重量部添加するのが好ましい。
【０１０３】
図１３は本実施例で使用したフルカラー画像形成用の電子写真装置の構成を示す断面図である。図において、１はカラー電子写真プリンタの外装筐で、図中の右端面側が前面である。１Ａはプリンタ前面板であり、該前面板１Ａはプリンタ外装筐１に対して下辺側のヒンジ軸１Ｂを中心に点線表示のように倒し開き操作、実線表示のように起こし閉じ操作自由である。プリンタ内に対する中間転写ベルトユニット２の着脱操作や紙詰まり時などのプリンタ内部点検保守等は前面板１Ａを倒し開いてプリンタ内部を大きく解放することにより行われる。この中間転写ベルトユニット２の着脱動作は、感光体の回転軸母線方向に対し垂直方向になるように設計されている。
【０１０４】
中間転写ベルトユニット２の構成を図１４に示す。中間転写ベルトユニット２はユニットハウジング２ａに、転写ベルト３、導電性弾性体よりなる第１転写ローラ４、アルミローラよりなる第２転写ローラ５、転写ベルトの張力を調整するテンションローラ６、転写ベルト上に残ったトナー像をクリーニングするベルトクリーナローラ７、クリーナローラ７上に回収したトナーをかきおとすスクレーパ８、回収したトナーを溜おく廃トナー溜め９ａおよび９ｂ、転写ベルトの位置を検出する位置検出器１０を内包している。この中間転写ベルトユニット２は、図１３に示されているように、プリンタ前面板１Ａを点線のように倒し開いてプリンタ外装筐１内の所定の収納部に対して着脱自在である。
【０１０５】
中間転写ベルト３は、絶縁性樹脂中に導電性のフィラーを混練して押出機にてフィルム化して用いる。本実施例では、絶縁性樹脂としてポリカーボネート樹脂（例えば三菱ガス化学製、ユーピロンＺ３００）９５重量部に、導電性カーボン（例えばケッチェンブラック）５重量部を加えてフィルム化したものを用いた。また、表面に弗素樹脂をコートした。フィルムの厚みは約３５０μｍ、抵抗は約１０⁷〜１０⁸Ω・ｃｍである。ここで、中間転写ベルト３としてポリカーボネート樹脂に導電性フィラーを混練し、これをフィルム化したものを用いているのは、中間転写ベルトの長期使用による弛みや、電荷の蓄積を有効に防止できるようにするためであり、また、表面を弗素樹脂でコートしているのは、長期使用による中間転写ベルト表面へのトナーフィルミングを有効に防止できるようにするためである。
【０１０６】
この転写ベルトを、厚さ１００μｍのエンドレスベルト状の半導電性のウレタンを基材としたフィルムよりなり、周囲に１０⁷Ω・cmの抵抗を有するように低抵抗処理をしたウレタンフォームを成形した第１転写ローラ４、第２転写ローラ５およびテンションローラ６に巻回し、矢印方向に移動可能に構成される。ここで、転写ベルトの周長は、最大用紙サイズであるＡ４用紙の長手方向の長さ（２９８ｍｍ）に、後述する感光体ドラム（直径３０ｍｍ）の周長の半分より若干長い長さ（６２ｍｍ）を足した３６０ｍｍに設定している。
【０１０７】
中間転写ベルトユニット２がプリンタ本体に装着されたときには、第１転写ローラ４は、中間転写ベルト３を介して感光体１１（図１４に図示）に約１．０ｋｇの力で圧接され、また、第２転写ローラ５は、中間転写ベルト３を介して上記の第１転写ローラ４と同様の構成の第３転写ローラ１２（図１４に図示）に圧接される。この第３転写ローラは中間転写ベルト３に従動回転可能に構成している。
【０１０８】
クリーナローラ７は、中間転写ベルト３を清掃するベルトクリーナ部のローラである。これは、金属性のローラにトナーを静電的に吸引する交流電圧を印加する構成である。なお、このクリーナローラ７はゴムブレードや電圧を印加した導電性ファーブラシであってもよい。
【０１０９】
図１３において、プリンタ中央には黒、シアン、マゼンタ、イエロの各色用の４組の扇型をした像形成ユニット１７Ｂｋ、１７Ｙ、１７Ｍ、１７Ｃが像形成ユニット群１８を構成し、図のように円環状に配置されている。各像形成ユニット１７Ｂｋ、１７Ｙ、１７Ｍ、１７Ｃは、プリンタ上面板１Ｃをヒンジ軸１Ｄを中心に開いて像形成ユニット群１８の所定の位置に着脱自在である。像形成ユニット１７Ｂｋ、１７Ｙ、１７Ｍ、１７Ｃはプリンタ内に正規に装着されることにより、像形成ユニット側とプリンタ側の両者側の機械的駆動系統・電気回路系統が相互カップリング部材（不図示）を介して結合して機械的・電気的に一体化する。
【０１１０】
円環状に配置されている像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙは支持体（図示せず）に支持されており、全体として移動手段である移動モータ１９に駆動され、固定されて回転しない円筒状の軸２０の周りに回転移動可能に構成されている。各像形成ユニットは、回転移動によって順次前述の中間転写ベルト３を支持する第２転写ローラ４に対向した像形成位置２１に位置することができる。像形成位置２１は信号光２２による露光位置でもある。
【０１１１】
各像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙは、中に入れた現像剤を除きそれぞれ同じ構成部材よりなるので、説明を簡略化するため黒用の像形成ユニット１７Ｂｋについて説明し、他色用のユニットの説明については省略する。
【０１１２】
３５はプリンタ外装筐１内の下側に配設したレーザビームスキャナ部であり、図示しな半導体レーザ、スキャナモータ３５ａ、ポリゴンミラー３５ｂ、レンズ系３５ｃ等から構成されている。該スキャナ部３５からの画像情報の時系列電気画素信号に対応した画素レーザ信号光２２は、像形成ユニット１７Ｂｋと１７Ｙの間に構成された光路窓口３６を通って、軸２０の一部に開けられた窓３７を通して軸２０内の固定されたミラー３８に入射し、反射されて像形成位置２１にある像形成ユニット１７Ｂｋの露光窓２５から像形成ユニット１７Ｂｋ内にほぼ水平に進入し、像形成ユニット内に上下に配設されている現像剤溜め２６とクリーナ３４との間の通路を通って感光体ドラム１１の左側面の露光部に入射し母線方向に走査露光される。
【０１１３】
ここで光路窓口３６からミラー３８までの光路は両隣の像形成ユニット１７Ｂｋと１７Ｙとのユニット間の隙間を利用しているため、像形成ユニット群１８には無駄になる空間がほとんど無い。また、ミラー３８は像形成ユニット群１８の中央部に設けられているため、固定された単一のミラーで構成することができ、シンプルでかつ位置合わせ等が容易な構成である。
【０１１４】
１２はプリンタ前面板１Ａの内側で給送ローラ３９の上方に配設した第３転写ローラであり、中間転写ベルト３と第３転写ローラ１２との圧接されたニップ部には、プリンタ前面板１Ａの下部に設けた紙給送ローラ３９により用紙が送られてくるように用紙搬送路が形成されている。
【０１１５】
４０はプリンタ前面板１Ａの下辺側に外方に突出させて設けた給紙カセットであり、複数の紙Ｓを同時にセットできる。４１ａと４１ｂとは紙搬送タイミングローラ、４２ａ・４２ｂはプリンタの内側上部に設けた定着ローラ対、４３は第３転写ローラ１２と定着ローラ対４２ａ・４２ｂ間に設けた紙ガイド板、４４ａ・４４ｂは定着ローラ対４２ａ・４２ｂの紙出口側に配設した紙排出ローラ対、４５は定着ローラ４２ａに供給するシリコーンオイル４６を溜める定着オイル溜め、４７はシリコーンオイル４６を定着ローラ４２ａに塗布するオイル供給ローラである。
【０１１６】
各像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙ、中間転写ベルトユニット２には、廃トナー溜めを設けている。
【０１１７】
以下、動作について説明する。
【０１１８】
最初、像形成ユニット群１８は図１３に示すように、黒の像形成ユニット１７Ｂｋが図示のように像形成位置２１にある。このとき感光体１１は中間転写ベルト３を介して第１転写ローラ４に対向接触している。
【０１１９】
像形成工程により、レーザ露光装置３５により黒の信号光が像形成ユニット１７Ｂｋに入力され、黒トナーによる像形成が行われる。この時像形成ユニット１７Ｂｋの像形成の速度（感光体の周速に等しい６０ｍｍ／ｓ）と中間転写ベルト３の移動速度は同一になるように設定されており、像形成と同時に第１転写ローラ４の作用で、黒トナー像が中間転写ベルト３に転写される。このとき第１転写ローラには＋１ｋＶの直流電圧を印加した。黒のトナー像がすべて転写し終わった直後に、像形成ユニット１７Ｂｋ、１７Ｃ、１７Ｍ、１７Ｙは像形成ユニット群１８として全体が移動モータ１９に駆動されて図中の矢印方向に回転移動し、ちょうど９０度回転して像形成ユニット１７Ｃが像形成位置２１に達した位置で止まる。この間、像形成ユニットの感光体以外のトナーホッパ２６やクリーナ３４の部分は感光体１１先端の回転円弧より内側に位置しているので、中間転写ベルト３が像形成ユニットに接触することはない。
【０１２０】
像形成ユニット１７Ｃが像形成位置２１に到着後、前と同様に今度はシアンの信号でレーザ露光装置３５が像形成ユニット１７Ｃに信号光を入力しシアンのトナー像の形成と転写が行われる。このときまでに中間転写ベルト３は一回転し、前に転写された黒のトナー像に次のシアンのトナー像が位置的に合致するように、シアンの信号光の書き込みタイミングが制御される。この間、第３転写ローラ１２とクリーナローラ７とは中間転写ベルト３から少し離れており、転写ベルト上のトナー像を乱さないように構成されている。
【０１２１】
以上と同様の動作を、マゼンタ、イエロについても行い、中間転写ベルト３上には４色のトナー像が位置的に合致して重ね合わされカラー像が形成された。最後のイエロトナー像の転写後、４色のトナー像はタイミングを合わせて給紙カセット４０から送られる用紙に、第３転写ローラ１２の作用で一括転写される。このとき第２転写ローラ５は接地し、第３転写ローラ１２には＋１．５ｋＶの直流電圧を印加した。用紙に転写されたトナー像は定着ローラ対４２ａ・４２ｂにより定着された。用紙はその後排出ローラ対４４ａ・４４ｂを経て装置外に排出された。中間転写ベルト３上に残った転写残りのトナーは、クリーナローラ７の作用で清掃され次の像形成に備えた。
【０１２２】
次に単色モード時の動作を説明する。単色モード時は、まず所定の色の像形成ユニットが像形成位置２１に移動する。次に前と同様に所定の色の像形成と中間転写ベルト３への転写を行い、今度は転写後そのまま続けて、次の第３転写ローラ１２により給紙カセット４０から送られてくる用紙に転写をし、そのまま定着した。
【０１２３】
なお、本装置では、像形成ユニットの構造として特定の現像法を用いた構造のものを使用しているが、他にコンベンショナルな現像法を用いた構造の像形成ユニットを用いることもできる。
【０１２４】
かかる電子写真装置により、前記製造したトナーサンプルを用いて画像出しを行ったところ、横線の乱れやトナーの飛び散り、文字の中抜けなどがなくベタ黒画像が均一で濃度が１．４の１６本／ｍｍの画線をも再現した極めて高解像度高画質の画像が得られた。画像濃度１．４以上の高濃度の画像が得られた。非画像部の地かぶりも発生していなかった。更に、１万枚の長期耐久テストに於いても、流動性、画像濃度とも変化が少なく安定した特性を示した。また転写においても中抜けは実用上問題ないレベルであり、転写効率は９０％であった。また、感光体、中間転写ベルトへのトナー（離型剤）のフィルミングも実用上問題ないレベルであった。
【０１２５】
【発明の効果】
以上のように本発明にかかるトナーの製造方法によれば、送り機能を主機能とする第１の混練セグメントと、練り機能を主機能とする第２の混練セグメントとからなり、各セグメント毎に混練設定温度を設定できるようにした複数の混練セグメントを具備する分割セグメント方式の混練機を用い、特定の混練温度設定条件にて、特定の軟化点を有する結着樹脂を含むトナー材料を混練することにより、結着樹脂中に添加剤が極めて良好に分散し、優れた定着性、耐オフセット性、現像性、及び転写効率が得られるトナーを再現性良く製造することができる。特に、プロセス速度が異なる機種間で使用した場合にも、良好な帯電性、定着性及び耐オフセット性が得られるトナーを製造することができる。また、特開平５−７２８９０号公報に提案した、現像器の小型化、簡素化、及び低コスト化を可能にした電子写真装置に適用した場合に、高濃度、低地かぶりの高画質画像を得ることができるトナーを製造することができる。また、中間転写体を用いた転写システムを具備する電子写真装置に適用した場合に、中抜けや飛び散りが防止され、高転写効率が得られるトナーを製造することができる。また、長期使用においても、感光体、中間転写体等へのフィルミングの発生を防止できるトナーを製造することができる。また、廃トナーリサイクルシステムを具備する電子写真装置に適用した場合に、帯電量の低下がなく、凝集物を生じず、長期に亘って、高画質画像を形成することができるトナーを製造することができる。
【図面の簡単な説明】
【図１】本発明のトナーの製造方法に使用される混練処理装置の一例の構成を概要的に示した断面図である。
【図２】図１に示した混練処理装置の混練軸の主要部の構成を示した側面図である。
【図３】図１、２に示した送りスクリュウの側面図である。
【図４】図１、２に示した送りスクリュウの正面図である。
【図５】図１、２に示した練りのニィーディングディスクの送りスクリュウの側面図である。
【図６】図１、２に示した練りのニィーディングディスクの送りスクリュウの正面図である。
【図７】図１、２に示したシールリングの側面図である。
【図８】図１、２に示したシールリングの正面図である。
【図９】図１に示したパイナップルリングの側面図である。
【図１０】図１に示したパイナップルリングの正面図である。
【図１１】本発明の実施例２で使用した現像方式が磁性一成分現像方式の電子写真装置の構成を示す断面図である。
【図１２】本発明の実施例４で使用した電子写真装置の構成を示す断面図である。
【図１３】本発明の実施例６で使用した電子写真装置の構成を示す断面図である。
【図１４】図１３に示した中間転写ベルトユニットの構成を示す断面図である。
【図１５】カラー電子写真装置の概略構成を示す断面図である。
【符号の説明】
２ 中間転写ベルトユニット
３ 中間転写ベルト
４ 第１転写ローラ
５ 第２転写ローラ
６ テンションローラ
１１ 感光体
１２ 第３転写ローラ
１５ バネ
１６ コロ
１７Ｂｋ・１７Ｃ・１７Ｍ・１７Ｙ 像形成ユニット
１８ 像形成ユニット群
２１ 像形成位置
２２ レーザ信号光
３５ レーザ露光装置
３８ ミラー
１０３ 混練軸
１０４ ベント孔
１０５ 送りのスクリュウ
１０６ 練りのニィーディングディスク
１０７ シールリング
１０８ パイナップルリング
１０９ 吐出口
Ｂ１１、Ｂ２２、Ｂ３３ 混練ブロック
１１ｒａ、１１ｒｂ、１１ｒｃ、１１ｒｄ、２２ｒａ、３３ｒａ 第１の混練セグメント
１１ｎａ、２２ｎａ、３３ｎａ 第２の混練セグメント
２０２ 感光体に内包された固定磁石
２０３ コロナ帯電器
２０４ グリッド電極
２０６ トナーホッパー
２０７ 現像剤
２０８ 電極ローラ
２０９ 電極ローラ内部に設置された磁石
２１１ スクレーパ
２１３ 転写ローラ
２１４ 突入ガイド
２１５ 搬送ガイド
２１６ 転写紙
２１８ クリーニングブレード
２１９ 廃トナーボックス
２２０ 廃トナー輸送管
２２３ 廃トナー[0001]
[Industrial application fields]
  The present invention relates to a method for producing toner used in an image forming apparatus (hereinafter referred to as an electrophotographic apparatus) that forms an image by electrophotography such as a copying machine, a printer, and a facsimile machine.
[0002]
[Prior art]
  In recent years, electrophotographic apparatuses are shifting from the purpose of office use to personal use, and there is a demand for technology that realizes downsizing, maintenance-free, and the like of the apparatus. For this reason, apparatuses are equipped with a waste toner recycling system, a system that generates less ozone, and the like.
[0003]
  The basic image forming process (printing process) of the electrophotographic apparatus will be described below.
[0004]
  First, a photoreceptor (hereinafter also referred to as an image carrier) is charged for image formation. As a charging method, there are a conventionally used method using a corona charger, a method in which the surface of a conductive roller is brought into direct contact with the surface of the photoreceptor, and the surface of the photoreceptor is uniformly charged. This charging method using a conductive roller is intended to reduce the amount of ozone generated. After charging the surface of the photoconductor, if it is a copier, a latent image is formed by irradiating the photocopy with light and irradiating the photoconductor through the lens system to form a latent image. An image signal is sent to the light-emitting diode or laser diode, and a latent image is formed by turning on and off the light from the light-emitting diode or laser diode. When the latent image, that is, the level of the surface potential is formed on the photoconductor, the photoconductor is visualized with toner that is a colored powder having a diameter of about 5 μm to 15 μm that is charged in advance. The toner adheres to the surface of the photoconductor according to the level of the surface potential of the photoconductor and is electrically transferred to a copy sheet (hereinafter also referred to as a transfer material). That is, the toner is positively or negatively charged in advance, and is electrically attracted to the copy sheet by applying a charge having a polarity opposite to the toner polarity from the back surface of the copy sheet. In this transfer process, not all the toner on the photoreceptor is transferred to the copy sheet, but a part of the toner remains on the photoreceptor. The residual toner is scraped off by a cleaning blade or the like at the cleaning unit and collected as waste toner. The toner transferred to the copy sheet is fixed to the copy sheet by heat or pressure in the fixing process. As a fixing method, a pressure fixing method for passing between two or more metal rolls, an oven fixing method for passing through a heating atmosphere by an electric heater, and two rollers in which at least one roller is built in a heater are provided. There is a hot roll fixing system that passes between the above rollers. Conventionally, the waste toner has been discarded without being reused. However, in recent years, the importance of restricting the unlimited disposal of industrial waste has been screamed from the viewpoint of protecting the global environment. Since toner is powder, careless disposal of toner can cause environmental pollution. For this reason, waste toner recycling in which waste toner is repeatedly used for image formation has been performed.
[0005]
  In the heat roll fixing method, since the surface of the heating roller and the toner surface on the copy paper are in pressure contact with each other, the thermal efficiency when the toner image is fused to the copy paper is good, and the toner can be fixed quickly. it can. However, in the heat roll fixing method, the toner is in pressure contact with the surface of the heating roller in a heated and melted state, so that a part of the toner adheres to the roller surface and again adheres to the copy paper and contaminates the image. (Hereinafter simply referred to as offset). As a method for preventing such an offset phenomenon, the surface of the heating roller is formed of a fluorine resin or silicon rubber which is heat resistant and has good releasability with respect to the toner, and further, an anti-offset liquid such as silicon oil is supplied to the surface of the heating roller. A method of coating the roller surface with a thin film is used. However, this method has the disadvantage that the odor is generated by heating a liquid such as silicon oil, and an extra device for supplying the liquid is required, so that the mechanism of the copying apparatus becomes complicated. Have. Further, in order to reliably prevent the offset, it is necessary to control the liquid supply to the roller surface with high accuracy, and the copying apparatus must be expensive. For this reason, there is a demand for a toner that does not generate an offset and can provide a good fixed image without supplying such an anti-offset liquid.
[0006]
  As is well known, toner for electrostatic charge development used in an electrophotographic method is generally constituted by dispersing a coloring component composed of at least a pigment or a dye in a binder resin, and further required. Accordingly, a plasticizer, a charge control agent, a magnetic material, a release agent and the like are dispersed in the binder resin. As the binder resin, a natural or synthetic resin is used, and a single kind or a mixture of plural kinds of resins are used. As a method for producing such toner, each material is preliminarily mixed at an appropriate ratio, the mixture is heated and kneaded by heat melting, the kneaded material is cooled, and the kneaded material is finely pulverized by an airflow type impact plate system or the like. Finally, the pulverized product is classified to obtain a toner base, and then an external additive is externally added to the toner base to complete the toner.
[0007]
  In the one-component development, a developer is composed only of toner, and in the two-component development, a developer is composed by mixing with a carrier made of toner and magnetic particles.
[0008]
  Conventional development methods for visualizing an electrostatic latent image by an electrophotographic method include a cascade development method, a touch-down development method, and a jumping development method. The cascade development method is a method in which a developer is directly sprinkled on a photoreceptor, and is disclosed in US Pat. No. 3,105,770. This cascade development method is the development method used in the first practical copying machine using the electrophotographic method. U.S. Pat. No. 3,866,574 discloses a developing method in which an AC bias is applied to a developing roller to cause one-component toner to fly. In this developing method, it is described that the AC bias applied to the developing roller is used for the purpose of activating the movement of the toner, and the toner flies to the image portion and returns to the middle in the non-image portion. Furthermore, as an improvement of the technique for applying this AC bias, there is a jumping development disclosed in Japanese Patent Publication No. 63-42256. In this jumping development method, toner is carried on a toner carrier, and a rigid or elastic regulating blade is installed on the toner carrier with a small gap between the carrier and the toner is regulated into a thin layer by this regulating blade. In this method, the toner is carried to the developing portion, and toner is attached to the image portion of the photoreceptor by an AC bias. This jumping development method is different from the above-described development method disclosed in US Pat. No. 3,866,574 in that the toner reciprocates in the image portion and the non-image portion.
[0009]
  In addition, an image forming process in an electrophotographic apparatus such as a full-color copying machine or a full-color printer that forms a full-color image is performed for each color. That is, the photosensitive member is charged by a corona discharge device, and an electrostatic latent image is formed by irradiating the surface of the photosensitive member with an optical signal corresponding to the first color latent image. The first color toner, for example, yellow toner is used. And developing the electrostatic latent image, and transferring the yellow toner image onto the transfer paper by bringing the obtained yellow toner image into contact with a transfer paper charged with a polarity opposite to the charged polarity of the toner. Thereafter, the yellow toner remaining on the surface of the photosensitive member is removed by a cleaning unit, and the surface of the photosensitive member is neutralized. Thereafter, the second, third, and fourth color toners such as magenta, cyan, and black are used. The same operation as that of the first color yellow toner is repeated to form a full-color image by superimposing the toner images of the respective colors on the transfer material, and fixing the superimposed toner image. In this full color image formation method, toner images of each color are sequentially formed on a single photoconductor surface, and the transfer paper wound around the transfer drum is repeatedly opposed to the photoconductor surface by the rotation of the transfer drum. A plurality of image forming units for each color arranged side by side, that is, a plurality of image forming units including a photoconductor for each color, In general, a continuous superimposing method in which the toner images of the respective colors are sequentially transferred by passing the transfer paper conveyed by each through the respective image forming units (image forming units) and the color images are superposed. As a device using a transfer drum system, for example, a color electrophotographic apparatus disclosed in JP-A-1-252882 can be cited.
[0010]
  FIG. 15 is a cross-sectional view showing a schematic configuration of the color electrophotographic apparatus. Hereinafter, the configuration and operation thereof will be briefly described. In FIG. 15, reference numeral 501 denotes a photoconductor, which is provided with a charger 502, a developing unit 503, a transfer drum 504, and a cleaner 505 so as to face each other. The developing unit 503 includes a Y developing unit 506 for creating a yellow toner image, an M developing unit 507 for creating a magenta toner image, a C developing unit 508 for creating a cyan toner image, and a black toner. The image forming apparatus includes a Bk developing device 509 for forming an image, and the entire developing device group is rotated so that each developing device can sequentially face the photosensitive member 501 and be developed. The transfer drum 512 and the photoconductor 501 rotate at a constant speed in the direction of the arrow while facing each other during operation.
[0011]
  When the image forming operation starts, the photosensitive member 501 rotates in the direction of the arrow and the surface thereof is uniformly charged by the charger 502. Thereafter, the surface of the photoconductor 501 is irradiated with a laser beam 510 modulated by a signal for forming a yellow image of the first color to form a latent image. Next, this latent image is first developed by the Y developing unit 506 facing the photoconductor to form a yellow toner image. Before the yellow toner image formed on the photoconductor 501 moves to a position facing the transfer drum 504, one sheet as a transfer material already sent from the paper supply unit 511 is placed on the outer periphery of the transfer drum 504. The tip is held by the claw portion 512 and wound, and the yellow toner image on the photoreceptor is opposed to meet at a predetermined position on the sheet. After the yellow toner image on the photosensitive member 501 is transferred to the paper by the action of the transfer charger 513, the surface of the photosensitive member is cleaned by the cleaner 505, and preparation for the next color image formation is made. Subsequently, magenta, cyan, and black toner images are formed in the same manner. At that time, in the developing unit 503, each developing device provided according to the color is opposed to the photosensitive member and can be developed. The diameter of the transfer drum 504 is sufficiently large so that the longest paper is wound and the developing device can be exchanged between the images of the respective colors.
[0012]
  Irradiation of the laser beam 510 for image formation of each color positionally matches the toner image of each color on the photoconductor 501 with the toner image already transferred onto the paper on the transfer drum 504 as the photoconductor 501 rotates. The timing is executed so as to face each other. In this way, the four color toner images are transferred onto the paper on the transfer drum 504, and a color image is formed on the paper. After all color toner images have been transferred, the sheet is peeled off from the transfer drum 504 by a peeling claw 514, and the toner image is fixed by a fixing unit 516 through a transport unit 515, and discharged outside the apparatus.
[0013]
  On the other hand, as an example of a color image forming apparatus using a continuous transfer system, the one described in JP-A-1-250970 can be cited. In such a color image forming apparatus, four image forming stations each including a photoconductor, an optical scanning unit, and the like are arranged to form an image of four colors, and the sheet conveyed to the belt passes under each photoconductor. Thus, the color toner images are superimposed. Further, as another method for forming a color image by superimposing toner images of different colors on a transfer material separately from the above two methods, each color toner image sequentially formed on a photoreceptor is placed on an intermediate transfer material. There is a system in which the toner images on the intermediate transfer material are transferred to a transfer sheet in a lump after being overlaid. This is disclosed in, for example, Japanese Patent Laid-Open No. 2-212867.
[0014]
[Problems to be solved by the invention]
  The above-described cascade development method has poor solid image reproducibility, as has been said conventionally. In addition, there is a disadvantage that the apparatus becomes large and complicated. In particular, the developing device for performing cascade development described in US Pat. No. 3,866,574 has the disadvantage of being complicated and expensive. On the other hand, in order to obtain a good toner image, the jumping development method requires that a toner thin layer having a very uniform thickness be formed on a toner carrier carrying a toner layer, which is expensive for a developing device that performs jumping development. Mechanical accuracy is required, and there is a drawback that the developing device is not easily manufactured. Further, the jumping development method has a drawback that a so-called sleeve ghost development occurs, in which the history of the previous image often remains in the toner thin layer on the toner carrier, and an unnecessary afterimage often appears in the obtained toner image. Further, there is a drawback that the construction of the developing device is complicated and the cost is increased. In view of the above drawbacks, the present applicant has proposed a developing method capable of realizing downsizing and high performance of a developing device in Japanese Patent Laid-Open No. 5-72890. In this developing method, unnecessary developer in a non-image area is removed by a photosensitive member including a fixed magnet and a developer recovery electrode roller (hereinafter referred to as an electrode roller) having a predetermined gap with the photosensitive member. It is a configuration. According to such a developing method, a solid image is faithfully reproduced and sleeve ghost is not generated, so that further downsizing, simplification, and cost reduction of the apparatus can be achieved.
[0015]
  However, in such a developing method, a bare electrode roller is made to face the photosensitive member, unnecessary developer on the photosensitive member is recovered by the electrode roller, and the recovered developer is removed from the electrode roller by a scraper to a developing device (hopper). However, the scraper does not stably scrape off the developer (toner), and the developer (toner) may slip through the scraper, resulting in image defects such as black streaks on the image. is there. This is because when the release agent with a low softening point added internally to the toner is poorly dispersed, it is removed from the toner during the development operation and fused and deposited on the surface of the scraper, so that the scraper scrapes off. This is because of a decrease.
[0016]
  Further, in such a developing method, a developer with higher performance is required for improving the image quality. That is, in such a developing method, the developer is transported to a developing field which is a narrow gap space between the photoconductor and the electrode roller without layer restriction, and the toner in the image portion of the electrostatic latent image is electrostatically charged. The remaining toner and carrier in the non-image area are collected to the electrode roller. At this time, if the toner charge distribution is broad, the developer is not regulated by the layer, so the toner is supplied in the solid black image area. Is not sufficient, unevenness occurs, and toner scatters in the character portion. Therefore, a toner having a narrower charge amount distribution is required. In addition, such a developing method requires a toner in which the internal additive is very well dispersed. This is because, in this developing method, the developer is first sprinkled on the entire surface of the image carrier, which is different from other conventional developing methods. This is because the developer and the photoreceptor are in contact with each other for a long time, and the poorly dispersed release agent released from the toner is more likely to adhere to the photoreceptor as compared with other conventional development methods.
[0017]
  As described above, from the viewpoint of protecting the global environment in recent years, it is preferable to recycle the toner remaining on the photoreceptor after development and recovered by the cleaning means. However, when the waste toner is recycled, since the waste toner is subjected to mechanical stress in the cleaner portion, the developing portion, and the transport pipe when returning the waste toner to the developing portion, the soft portion of the toner in which the release agent exists As a result, it is easy to cause image degradation due to dropping of the above-mentioned release agent from the toner, and once waste toner used for image formation is mixed with new toner in the developing device, the toner is charged. There is a disadvantage that the quantity distribution becomes broad and the amount of reverse polarity toner increases, and the quality of the copied image is degraded.
[0018]
  Further, in the transfer method using the conductive elastic roller, a transfer paper is inserted between the image carrier and the conductive elastic roller, and a transfer bias voltage is applied to the conductive elastic roller, thereby the image carrier. The toner on the surface is transferred to the transfer paper by electrostatic force. However, the transfer system using the conductive elastic roller has a problem that the transfer paper is stained. This is because when the toner on the image carrier is transferred to transfer paper using a transfer roller, the transfer roller is in contact with the image carrier at a predetermined pressure in the absence of the transfer paper, and there is a lot of fog in the development process. This is because the transfer roller is contaminated by the toner due to the fog, and the transfer roller contaminated with the toner comes into contact with the back surface of the transfer paper sent.
[0019]
  In full-color image formation, in the transfer method using the transfer drum, the transfer drum around which the paper is wound is rotated at the same speed with respect to the photosensitive member, and the leading edge (start) timing at the time of transferring each color toner image is adjusted. As a result, the positions of the toner images of the respective colors coincide with each other on the paper wound around the transfer drum. However, since the paper needs to be wound around the transfer drum, the diameter of the transfer drum needs to be a certain size or more. In addition, since the structure is very complicated and high accuracy is required, the apparatus is large and expensive. Further, there is a problem that stiff paper such as postcards and cardboard cannot be used because it cannot be wound around a transfer drum. In the continuous transfer method, an image forming position corresponding to the number of colors is provided, and it is only necessary to pass sheets one after another. Therefore, a transfer drum is unnecessary, but in this method, a latent image is formed on the photosensitive member. Since the number of latent image forming means such as laser optical systems for forming is required corresponding to the number of colors, the structure of the apparatus becomes very complicated and expensive, and there are a plurality of image forming positions. The relative displacement of the image forming portions of the respective colors, the eccentricity of the rotation shaft, the shift of the parallelism of the respective portions, etc. directly affect the color displacement, and it is difficult to stably form a high-quality image. There was a problem. In particular, it is necessary to accurately perform alignment between the respective colors of the latent image by the latent image forming means, which is equivalent to an image exposure system that is a latent image forming means as disclosed in Japanese Patent Laid-Open No. 1-250970. There was a problem that a device and a complicated configuration were required. On the other hand, the transfer method using the intermediate transfer member described in JP-A-2-212867 does not require a complicated optical system, and can use a stiff paper such as a postcard or cardboard as a transfer paper. Since the intermediate transfer belt is flexible, there is an advantage that the apparatus itself can be downsized as compared with the transfer drum method and the continuous transfer method. By the way, it is ideal that all the toner is transferred at the time of transfer, but in reality, a partial transfer residue is generated, and the transfer efficiency is not 100%, but generally about 75 to 85%. The toner remaining after transfer is scraped off by a cleaning blade or the like in the process of cleaning the photoconductor to become waste toner. In such a transfer method using an intermediate transfer member, the toner undergoes at least two transfer steps from the photosensitive member to the intermediate transfer member, and further from the intermediate transfer member to the transfer paper. Even if the efficiency is 85%, the total transfer efficiency is reduced to 72% by two times of transfer, and when the transfer efficiency in one transfer is 75%, the two times of transfer, The total transfer efficiency is reduced to 56%, and about half of the toner becomes waste toner. Therefore, in practice, in the transfer method using the intermediate transfer member, there is a problem that the cost of the toner is increased, and the volume of the waste toner box for storing the waste toner has to be increased. There is a problem that it cannot be fully achieved. In addition, since the four-color toner image is superimposed on the intermediate transfer member in the intermediate transfer member method, the full-color toner image superimposed on the intermediate transfer member has a significantly different amount of toner (toner layer thickness) locally. It becomes. Therefore, when a full color toner image is transferred to a transfer sheet, a pressure difference is generated in the toner image, and a “collapse” phenomenon occurs in which a part of the image is not transferred but becomes a hole due to the aggregation effect of the toner. There is a problem. In particular, if a material with a high toner release effect is used for the intermediate transfer member in order to ensure cleaning when the transfer paper is jammed, the “blank” phenomenon appears remarkably and the quality of the image is significantly reduced. End up. Further, in characters, lines, and the like, the amount of toner increases due to edge development, and toner aggregation due to pressurization occurs more remarkably, and the “collapse” phenomenon appears more prominently. It appears even more prominently in high humidity and high temperature environments.
[0020]
  Conventionally, a different type of toner is used for each model having a different process speed in a copying machine, a printer, and a FAX. In order to improve offset resistance for low speed machines, a binder resin material with high viscoelasticity and a high softening point is used, and for high speed machines, it is difficult to obtain the amount of heat required for fixing, thus improving fixability. This is because a binder resin having a lowered softening point is used. Here, the process speed is related to the copying processing capacity of the machine per time, and is usually indicated by the peripheral speed of the photoconductor. The peripheral speed of the photoconductor determines the conveyance speed of the copy paper. From the viewpoint of toner cost, it is desirable that toner can be shared by models with different process speeds.
[0021]
  As described above, as a toner fixing method, a heat roll fixing method is generally used, and as a toner for the heat roll fixing method, an offset does not occur even if an offset prevention liquid is not supplied, which is good. There is a demand for a toner capable of obtaining a stable fixed image. That is, there is a demand for a toner having a high fixing strength, which is an adhesion force to paper, and having excellent offset resistance that prevents adhesion to a heat roller (hereinafter, the fixing strength is referred to as fixing property). Therefore, various measures have been conventionally taken, such as improvement of the binder resin. For example, JP-A-59-148067 has a low molecular weight part and a high molecular weight part, and specifies the peak value of the low molecular weight part and the dispersity (Mw / Mn) of the low molecular weight part and the high molecular weight part. A toner having both fixing property and anti-offset property is disclosed by using the unsaturated ethylenic polymer as a binder resin and dispersing a polyolefin having a specified softening point in the binder resin. . JP-A-56-158340 discloses a specific low molecular weight polymer component (hereinafter also simply referred to as a low molecular weight component) and a specific high molecular weight polymer component (hereinafter simply referred to as a high molecular weight) as a binder resin. A toner has been proposed in which a fixing component is ensured by a low molecular weight component and offset resistance is secured by a high molecular weight component. JP-A-58-223155 discloses an unsaturated ethylene polymer having a maximum value in the molecular weight region of 1000 to 10,000 and 200,000 to 1,000,000, and Mw / Mn in the range of 10 to 40. Using a resin consisting of a binder resin, a polyolefin with a specific softening point is dispersed in this binder resin, ensuring fixing properties with low molecular weight components and offset resistance with high molecular weight components and polyolefins. Toners designed to do this have been proposed.
[0022]
  In order to increase the fixing strength on a high-speed machine, if a binder resin having a low melt viscosity or a low molecular weight is used, the toner adheres to the carrier during two-term development, so-called spent In the case of one-component development, the toner tends to adhere to the doctor blade or the developing sleeve. Further, when used in a low speed machine, an offset in which the toner adheres to the heat roller at the time of fixing and a blocking in which the toner is fused during long-term storage are likely to occur. In other words, by blending the high molecular weight component and the low molecular weight component, it is possible to achieve both fixing strength and offset resistance for a narrow range of process speeds. difficult. In order to support a wide range of process speeds, it is necessary to configure a higher molecular weight component and a lower low molecular weight component, but in high speed machines, the fixing strength can be increased by increasing the low molecular weight component, Offset resistance deteriorates, and low speed machines can increase offset resistance by increasing the high molecular weight component. However, increasing the high molecular weight component reduces the pulverization property of the toner, which reduces the productivity. Arise. Accordingly, as described above, the offset resistance can be improved by dispersing a low softening point release agent such as polyolefin in a binder resin obtained by blending or copolymerizing a high molecular weight component and a low molecular weight component. However, the low softening point release agent has poor dispersibility in the binder resin due to its high releasability. It is liberated and contaminates the carrier, the photoreceptor and the developing sleeve. In particular, a resin composed of a low molecular weight component and a high molecular weight component and having a wide molecular weight distribution is more likely to cause poor dispersion of the additive. This is because when kneading at low temperature, the high molecular weight component is kneaded without being sufficiently melted, and when kneading at high temperature, the low molecular weight component becomes low in viscosity and less subject to kneading stress, and the balance between temperature and dispersibility is balanced. This is because it becomes extremely severe. In addition, when kneaded at a low temperature, a high stress is applied to the high molecular weight component, causing a molecular breakage of the high molecular weight component, which tends to cause a decrease in molecular weight.
[0023]
  Conventionally, a technique for improving the dispersibility of various internal additives in a binder resin in a kneading step in toner production has been proposed. For example, Japanese Patent Laid-Open No. 6-194878 proposes setting the set temperature of the cylinder of the kneading machine within 20 ° C. with respect to the minimum temperature of the kneaded material discharged from the kneading machine. In this publication, with this configuration, the resin is sufficiently melted while the kneaded material of the toner raw material moves in the kneading cylinder, and even in this melting, the viscosity is not lowered and a certain degree of stress is applied. The kneaded material is discharged from the discharge port. Japanese Laid-Open Patent Publication No. 6-161153 discloses that the kneading temperature is 20 ° C. or less with respect to the melting temperature of the resin and the discharge temperature is 35 ° C. or less of the melting temperature of the resin. In this publication, with such a configuration, the wax is uniformly dispersed in the binder resin with a small particle size, and the filming of the wax on the photoreceptor due to the separation of the wax from the toner, and the black spots, fog, etc. associated therewith Does not occur. Japanese Patent Laid-Open No. 6-266159 proposes setting the barrel temperature, the toner softening point, and the discharge temperature of the front and rear stages of the kneader to a certain relationship. According to the publication, such a configuration improves the dispersibility of the additive in the binder resin and improves the chargeability of the resulting toner.
[0024]
  However, the method disclosed in the above publication uses a kneader in which the kneading shaft is composed only of the screw portion. In practice, a large improvement in kneading performance is expected simply by limiting the kneading temperature. Can not. This is because the screw part has a feeding function as a main function and does not exhibit a kneading function so much.
[0025]
  The present invention has been made in view of the above problems, and a toner manufacturing method capable of manufacturing a toner having a narrow charge distribution with an additive dispersed uniformly in a binder resin with good reproducibility. The purpose is to provide.
[0026]
  Another object of the present invention is that the additive is uniformly dispersed in a binder resin obtained by blending or copolymerizing a high molecular weight polymer component and a low molecular weight polymer component, and a narrow charge distribution can be obtained. It is an object of the present invention to provide a toner manufacturing method capable of manufacturing a toner capable of obtaining excellent fixability and offset resistance with good reproducibility.
[0027]
  Another object of the present invention is to produce a toner having good chargeability, fixing property and offset resistance with good reproducibility when used between models having different process speeds. An object of the present invention is to provide a toner manufacturing method that can be used.
[0028]
  Another object of the present invention is to provide a high density and low ground when applied to an electrophotographic apparatus proposed in Japanese Patent Laid-Open No. 5-72890, which enables downsizing, simplification, and cost reduction of a developing device. An object of the present invention is to provide a toner production method capable of producing a high-quality image with fog and capable of producing a toner capable of preventing fusion to a scraper with good reproducibility.
[0029]
  Another object of the present invention is to produce a toner with high reproducibility, which is prevented from being lost or scattered when applied to an electrophotographic apparatus having a transfer system using an intermediate transfer member. An object of the present invention is to provide a toner manufacturing method that can be used.
[0030]
  Another object of the present invention is to provide a toner manufacturing method capable of manufacturing a toner capable of preventing the occurrence of filming on a photoconductor, an intermediate transfer body and the like with long reproducibility. And
[0031]
  Another object of the present invention is that when applied to an electrophotographic apparatus equipped with a waste toner recycling system, there is no decrease in charge amount, no agglomerates are formed, and a high-quality image is formed over a long period of time. An object of the present invention is to provide a toner production method capable of producing a toner that can be produced with good reproducibility.
[0032]
[Means for Solving the Problems]
  The method for producing the toner of the present invention comprises obtaining a kneaded melt of a toner material containing at least a binder resin, a colorant, and a release agent, and then cooling and pulverizing the kneaded melt to obtain a toner that is colored resin fine particles. In the manufacturing method, the step of obtaining a kneaded melt of the toner material includes a first kneading segment having a feeding function as its main function and a second kneading segment having a kneading function as its main function. , Having a plurality of kneading segments that can individually set the temperature of the heating cylinder for each segment, the plurality of kneading segmentssoThe first kneading segment and the second kneading segment are arranged adjacent to each other so that the material to be kneaded is kneaded in the second kneading segment immediately after being kneaded in the first kneading segment. A plurality of kneaded blocks formedAnd kneadingThe material to be kneaded is input from the material input port provided in the kneading segment at one end of the apparatus,ConcernedThe kneaded melt is discharged from the discharge port provided in the kneading segment at the other end of the device.In the kneading blockThe preset kneading temperature of the second kneading segment is Tmn (° C.), the preset kneading temperature of the first kneading segment is Tmr (° C.), the discharge temperature of the kneaded melt is Tmt (° C.), and the binder resin When the softening point is Tsp (° C.)To satisfy the following equations (Equation 1, Equation 2, Equation 3) simultaneouslyThe toner material is kneaded.
[Formula 1] Tmr-30 ° C. ≦ Tmn ≦ Tmr−1 ° C.
[Equation 2] Tmn + 5 ° C. ≦ Tmt ≦ Tmn + 80 ° C.
[Equation 3] Tsp-50 ° C. ≦ Tmr ≦ Tsp
[0033]
  It is preferable that the toner material is kneaded so that all the first kneading segments and all the second kneading segments in the kneading block simultaneously satisfy the formulas (Equation 1, Equation 2, Equation 3). .
[0034]
  Further, it is preferable that the toner material is kneaded so that all the first kneading segments and all the second kneading segments simultaneously satisfy the following two expressions (Equations 4 and 5).
[ Number 4 ] Tsp-50 ° C. ≦ Tmn ≦ Tsp
[ Number 5 ] Tsp + 5 ° C ≦ Tmt ≦ Tsp + 50 ° C
[0035]
  Conventionally, kneading devices such as roll mills, kneaders, and extruders have been used in the kneading process, which occupies an important position in determining the toner characteristics in the toner manufacturing process, and are particularly widely used among them. Is a twin-screw extruder because continuous production is possible. Such a twin-screw extruder is generally a mesh type shallow groove twin-screw extruder in which the kneading shaft rotates at a high speed, and depending on the material to be kneaded, the kneading shaft has a fully meshing type in the same direction rotation specification, A kneading shaft having a partially meshing type with different direction rotation is selected and used. Normally, such a mesh type shallow groove twin screw extruder is a divided segment system in which a cylinder and a kneading shaft are divided into a plurality of segments, and a heating cylinder is provided so that a constant kneading temperature can be set for each segment. In addition, water cooling for cooling flows. Further, the kneading shaft passing through the cylinder is mainly composed of a feeding portion having a function of conveying the kneaded material forward while being heated and melted, and a kneading portion mainly having a function of kneading. The feeding portion has an S-helical shape, and the kneading strength due to the shearing action is low. Conversely, the kneading portion has a high kneading strength due to a strong shearing force.
[0036]
  In the toner production method of the present invention having the above-described configuration, the temperature setting of the feed section in the kneading shaft of the twin-screw extruder and the cylinder in the mixing section determines the colorant in the binder resin when kneading the toner material. This is an important factor for improving the dispersibility of internal additives such as the internal additives, but it is possible to disperse the internal additives to a satisfactory level simply by defining the ratio of the kneading part to the entire kneading shaft. The first kneading segment having the feeding function as the main function and the second kneading segment having the kneading function as the main function are obtained based on the knowledge that the defective toner is generated. Using a split segment type kneader comprising a plurality of kneading segments, each of which can set a kneading set temperature for each segment. If the set kneading temperature, the kneading temperature of the second kneading segment, the discharge temperature of the kneaded melt, and the softening point of the binder resin are set so as to satisfy a specific relationship, the internal additive is bound. The present inventors have found that it is possible to produce a toner that is uniformly and uniformly dispersed in a resin, has a narrow charge amount distribution, and has excellent fixability and offset resistance.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
  Of the present inventionMethodThen, as described above, the first kneading segment having a feeding function as a main function and the second kneading segment having a kneading function as a main function, and a kneading set temperature can be set for each segment. In a split-segment kneader having a plurality of kneading segments, the kneading temperature Tmn (° C.) of the second kneading segment, the discharge temperature Tmt (° C.) of the kneaded melt, and the softening point Tsp (° C. of the binder resin) ) Are set so that they satisfy the above three expressions (Equation 1, Equation 2, Equation 3) simultaneously. Thereby, aggregation of the additive in the binder resin, particularly aggregation of the release agent added for preventing the offset can be prevented. More specifically, it is possible to prevent uneven distribution of additives in a low molecular weight component or a high molecular weight component when a binder resin having a wide molecular weight distribution, which has been extremely difficult in the past, is used.
[0038]
  Even if the binder resin and the additive are not sufficiently wet, the dispersibility of the additive will not be improved, and the binder resin will be heated above the softening point to significantly reduce the viscosity of the binder resin. Even if kneaded in a wet state, the dispersibility does not improve because the stress due to kneading does not work effectively. In the kneader of the segmented segment system, the resin is melted by heating from the kneader and self-heating, and is sent to the kneading part with improved wettability between the additive and the binder resin. In the first configuration of the present invention, the setting kneading temperature of the second kneading segment having the kneading function as a main function is the same as “the temperature lower by 50 ° C. than the softening point of the binder resin” to “the softening point of the binder resin”. Because it is set within the range of `` Temperature '', the binder resin melts moderately, the binder resin and additive are sufficiently wetted, and the mixture of binder resin and additive is effective for kneading stress. Thus, a kneaded melt that is uniformly and uniformly dispersed can be obtained without aggregation of the additive in the binder resin. The set kneading temperature of the first kneading segment is preferably not lower than 45 ° C. and more preferably not higher than 40 ° C. than the softening point of the binder resin. When the set kneading temperature of the first kneading segment becomes higher than the softening point of the binder resin, the binder resin is excessively melted, and the release agent aggregates in the low molecular weight polymer component of the binder resin. When the set kneading temperature of the first kneading segment is lower than the softening point of the binder resin by 50 ° C., the binder resin cannot be completely melted, the wettability of the binder resin and the additive is deteriorated, and the additive is fine. Will not disperse. Furthermore, in the first configuration of the present invention, the discharge temperature of the melt-kneaded product is within the range of “temperature 5 ° C. lower than the softening point of the binder resin” to “temperature higher by 50 ° C. than the softening point of the binder resin”. Therefore, self-heating of the kneaded product during kneading is promoted, and moderate stress is applied to the kneaded product to improve the dispersibility of the internal additive. The discharge temperature of the melt-kneaded product is preferably not higher than 40 ° C., more preferably not higher than 35 ° C., than the softening point of the binder resin.
[0039]
  In the present invention, as described above, the first kneading segment having the feeding function as the main function and the second kneading segment having the kneading function as the main function are set, and the kneading set temperature is set for each segment. In a split-segment kneader having a plurality of kneading segments, the material to be kneaded is kneaded in the second kneading segment immediately after being kneaded in the first kneading segment. A plurality of kneading blocks in which the first kneading segment and the second kneading segment are arranged adjacent to each other, the set kneading temperature Tmn (° C.) of the second kneading segment, and the first kneading segment of the kneading block The set kneading temperature Tmr (° C.), the kneaded melt discharge temperature Tmt (° C.), and the softening point Tsp (° C.) of the binder resin are expressed by the above three formulas (Number 1 to number 3) At the same time. Thereby, aggregation of the additive in the binder resin, particularly aggregation of the release agent added for preventing the offset and / or improving the fixability can be prevented. More specifically, it is possible to prevent uneven distribution of additives in a low molecular weight component or a high molecular weight component when a binder resin having a wide molecular weight distribution, which has been extremely difficult in the past, is used. This is because, for each kneading block, the setting kneading temperature of the second kneading segment having the kneading function as a main function is set to “temperature lower by 30 ° C. than the first kneading segment setting kneading temperature” to “setting of the first kneading segment”. Since the temperature is set within the range of 1 ° C. lower than the kneading temperature, an appropriate shear force is applied to the mixture without unnecessarily increasing the viscosity of the binder resin and additive mixture in the second kneading segment. This is because the additive is finely dispersed. The set kneading temperature of the second kneading segment is preferably in the range of “temperature lower by 25 ° C. than the first kneading segment setting kneading temperature” to “temperature lower by 4 ° C. than the setting kneading temperature of the first kneading segment”. More preferably, it is set in the range of “temperature lower by 20 ° C. than the set kneading temperature of the first kneading segment” to “temperature lower by 6 ° C. than the set kneading temperature of the first kneading segment”. It is good. When the set kneading temperature of the second kneading segment exceeds 1 ° C. lower than the set kneading temperature of the first kneading segment, the shearing force effectively acts due to the increase in the viscosity of the binder resin and additive mixture. Otherwise, the dispersibility of the additive in the high molecular weight polymer component of the binder resin is reduced. When the set kneading temperature of the second kneading segment is lower than the temperature of 30 ° C. lower than the setting kneading temperature of the first kneading segment, the load torque increases and the molecular chain breakage of the polymer component increases. Produce. Further, in the second configuration, the discharge temperature of the melt-kneaded product is 80 ° C. higher than the set kneading temperature of the second kneading segment to “the temperature 5 ° C. higher than the set kneading temperature of the second kneading segment”. Since the temperature is set in the range of “temperature”, self-heating of the kneaded product during kneading is promoted, and moderate stress is applied to the kneaded product to improve the dispersibility of the internal additive. The discharge temperature of the melt-kneaded product is preferably not more than 70 ° C. higher than the set kneading temperature of the second kneading segment, more preferably 60 ° C. higher than the set kneading temperature of the second kneading segment. It ’s better not to get too high. Further, in the second configuration, the set kneading temperature of the first kneading segment in the kneading block ranges from “temperature lower by 50 ° C. than the softening point of the binder resin” to “the same temperature as the softening point of the binder resin”. In the kneading block, the binder resin melts moderately, the binder resin and additive are sufficiently wetted, and the mixture of binder resin and additive is effective for kneading stress. It has a suitable working viscosity, and the additive is uniformly and uniformly dispersed in the binder resin without aggregation.
[0040]
  In the present invention, if the third configuration obtained by compromising the first configuration and the second configuration is used, both effects can be obtained, and the dispersibility of the additive in the binder resin is further improved. It will be.
[0041]
  In the above, the discharge temperature (Tmt) of the kneaded melt is determined by the characteristics of the binder resin, the characteristics and blending amount of the additive, the peripheral speed of the kneading shaft, the material supply amount, the kneading set temperature, etc. In particular, it is strongly influenced by the properties of the binder resin (molecular weight, softening point, viscoelasticity, etc.) and kneading set temperature.
[0042]
  In the present invention, the binder resin contains at least a polymer obtained by polymerizing a vinyl monomer. Specific examples of vinyl monomers include styrene, α-methylstyrene, p-chlorostyrene substituted styrene, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, acrylic acid Acrylic acid alkyl esters such as octyl, isobutyl acrylate and hexyl acrylate, methacrylic acid such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, isobutyl methacrylate, dodecyl methacrylate and hexyl methacrylate Mention may be made of alkyl esters. As a method for producing the polymer, known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be used. In the present invention, a polymer obtained by polymerizing such a vinyl monomer is a main component of the binder resin, but if necessary, other than the polymer obtained by polymerizing the vinyl monomer. A polymer such as a polyester resin, an epoxy resin, a polyurethane resin, or the like can be contained in the binder resin.
[0043]
  In the present invention, in order to make the toner compatible with a wide range of development process speeds (140 mm / s to 480 mm / s), the toner fixing property and charging property are improved by improving the dispersibility of the additive during the kneading. In addition to further increasing the penetrating power to the paper due to the thermal melting of the binder resin, increasing the slipperiness of the surface of the toner fixing image, and having an appropriate viscoelasticity to improve the offset resistance It is necessary to. In order to increase the penetrating power to paper and improve the offset resistance, it is preferable to specify the composition, glass transition point, and molecular weight of each of the low molecular weight polymer component and the high molecular weight polymer component of the binder resin. Specifically, the low molecular weight polymer component includes a styrene polymer having a weight average molecular weight in the range of 2500 to 20,000 and a glass transition point of 50 ° C. or higher, and the high molecular weight polymer component has a weight average molecular weight. Is a glass transition point in the range of 50 to 70 ° C., preferably a weight average molecular weight of 120,000 or more and a glass transition point of 55 to 70 ° C., more preferably a weight average molecular weight of 150,000 or more. It is preferable to use a styrene-acrylic copolymer having a transition point in the range of 55 to 65 ° C. The blending ratio of these low molecular weight polymer component and high molecular weight polymer component is preferably in the range of 9: 1 to 5: 5. The softening point of the binder resin may be in the range of 110 to 160 ° C, preferably in the range of 110 to 150 ° C, and more preferably in the range of 115 to 140 ° C. Furthermore, in order to further improve the fixability and pulverizability during pulverization in the production stage, the binder resin preferably contains 50 to 95% by weight of a styrene component.
[0044]
  The weight average molecular weight of the binder resin is a value measured by gel permeation chromatography using several types of monodisperse polystyrene as a standard sample. That is, it is a value measured by flowing tetrahydrofuran at a flow rate of 1 ml / min at a temperature of 25 ° C. and injecting 10 mg of a tetrahydrofuran sample solution having a concentration of 0.5 g / dl by weight into the sample. The measurement conditions are conditions in which the molecular weight distribution of the target sample is included in a range in which the logarithm of the molecular weight and the count number are linear in a calibration curve obtained with several types of monodisperse polystyrene standard samples. The softening point of the binder resin is a nozzle with a diameter of 1 mm by applying a load of 20 kg / cm @ 2 with a plunger while heating a 1 cm @ 3 sample at a heating rate of 6 DEG C./min with a flow tester (CFT500) manufactured by Shimadzu Corporation. From the relationship between the plunger drop amount and the temperature rise temperature characteristic, the softening point is the temperature corresponding to 1/2 of the characteristic line.
[0045]
  The use of a binder resin in which the composition, glass transition point, and molecular weight in each of the low molecular weight polymer component and the high molecular weight polymer component are used, the fixing strength of the toner fixed image evaluated by the tape peeling test is improved. When the surface of the toner fixed image is rubbed, the toner is easily peeled off from the transfer material. In the present invention, in order to increase the scratch resistance of the toner-fixed image, it is preferable to contain resin fine particles having a low dynamic friction coefficient in the toner. In the conventional toner manufacturing method, when resin particles having a low dynamic friction coefficient are added to the toner, the resin particles are strongly aggregated in the binder resin during kneading, and it is difficult to uniformly disperse the resin particles. However, the toner manufacturing method of the present invention can uniformly and uniformly disperse the resin particles having such a low dynamic friction coefficient in the binder resin. A toner having a narrow charge amount distribution can be produced without generating a charged toner, and a toner capable of obtaining a high fixing strength not only for a solid black image but also for a line image without causing background fog and toner scattering can be obtained. .
[0046]
  In the present invention, the release agent having a low softening point added to the binder resin is a low molecular weight polyalkylene such as low molecular weight polyethylene or low molecular weight polypropylene, ethylene bisamide, carnauba wax, montan wax, paraffin wax. These may be used alone or in combination of two or more. These are incompatible with the binder resin and preferably have a liberated form. The melting point of the mold release agent is 80 to 160 ° C, preferably 85 to 155 ° C, more preferably 90 to 140 ° C. When the melting point is higher than 160 ° C., the release agent does not melt at the time of fixing, the release agent does not elute at the interface between the fixing hard roller and the toner, and high-temperature offset is likely to occur, and when the melting point is 80 ° C. or less As a result, the heat resistance of the resin is reduced, and aggregation and solidification are likely to occur. The release agent is generally added in an amount of 0.1 to 20 parts by weight, preferably 1.0 to 15 parts by weight, per 100 parts by weight of the binder resin.
[0047]
  In the present invention, resin fine particles having a low dynamic friction coefficient can be added to the binder resin as described above. Low dynamic friction coefficient resin fine particles are resin fine particles having a dynamic friction coefficient of 0.3 or less. Specifically, polyalkylene fine particles, tetrafluoride or trifluoride resin fine particles, melamine fine particles, polymethyl methacrylate fine particles, polystyrene fine particles. And polyacetal fine particles. Among these, polyalkylene fine particles can also be used as the release agent. The average particle size of the resin fine particles is in the range of 0.1 to 5 μm, preferably 0.2 to 4 μm, more preferably 0.3 to 3 μm. The resin fine particles are generally added in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1.0 to 10 parts by weight per 100 parts by weight of the binder resin. Here, the dynamic friction coefficient of the resin fine particles is measured according to JIS K 7125, that is, as a friction material for the test piece, polycarbonate, nylon, polyacetal, acrylic, vinyl chloride resin, ABS resin, polypropylene, polystyrene, 4 fluorine The average value of the dynamic friction coefficient with each material to be rubbed was obtained using a modified resin as a reference for the dynamic friction coefficient of the sample.
[0048]
  In the present invention, a suitable pigment or dye is blended in the binder resin for the purpose of coloring the toner and / or controlling the charge. Examples of such pigments or dyes include carbon black, iron black, graphite, nigrosine, azo dye metal complexes, phthalocyanine blue, DuPont oil red, aniline blue, benzidine yellow, and rose bengal, one of these. Or 2 or more types are mixed and used. An amount necessary for coloring and / or charge control is added to the binder resin.
[0049]
  In the present invention, magnetic powder can be added to the binder resin as necessary. Specific examples include metal powders such as iron, manganese, nickel, and cobalt, and ferrites such as iron, manganese, nickel, cobalt, and zinc. The average particle size of the powder is generally 1 μm or less, preferably 0.6 μm or less. Magnetic powder is added in an amount of 15 to 70% by weight based on the total toner. When the addition amount is 15% by weight or less, the toner scattering tends to increase, and when it is 70% by weight or more, the charge amount of the toner decreases and the image quality tends to deteriorate.
[0050]
  In the present invention, it is preferable to externally add hydrophobic silica to the toner particles. In the case of a negatively chargeable toner, hydrophobic silica surface-treated with silicone oil is preferable, and in the case of a positively chargeable toner, hydrophobic silica surface-treated with organopolysiloxane is preferred. Moreover, the BET specific surface area by nitrogen adsorption of this hydrophobic silica is 50-350 m.²/ G is preferable. The hydrophobic silica is generally added in an amount of 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, per 100 parts by weight of the toner base particles.
[0051]
  The toner manufacturing process basically includes mixing processing of various materials, melt kneading processing, pulverization classification processing, and external addition processing in this order.
[0052]
  The mixing process is a process in which the binder resin and the additive to be dispersed in the binder resin are uniformly dispersed by a mixer having a stirring blade. As the mixer, a known mixer such as a super mixer (manufactured by Kawada Seisakusho), a Henschel mixer (manufactured by Mitsui Miike Kogyo Co., Ltd.), a PS mixer (manufactured by Shinko Pantech Co., Ltd.) or a Ladige mixer is used.
[0053]
  The kneading process is a process of dispersing the additive in the binder resin by a shearing force, and as described above, the temperature condition is set to the above-described temperature by a split segment type kneader in which the cylinder and the kneading shaft are divided into a plurality of segments. Done.
[0054]
  In the pulverization classification process, the toner lump obtained by kneading and cooling is roughly pulverized by a cutter mill or the like, and then finely pulverized by a jet mill pulverization (for example, IDS pulverizer, Nippon Pneumatic Industry), etc. Accordingly, the fine powder particles are cut by an airflow classifier to obtain toner particles (toner base particles) having a desired particle size distribution. Mechanical pulverization and classification are also possible. For example, a kryptron pulverizer (Kawasaki Heavy Industries) or a turbo mill (a pultron pulverizer that pulverizes by putting toner into a minute gap between a rotating roller and a fixed stator. Turbo industry) is used. By this classification treatment, toner particles (toner base particles) having a volume average particle diameter in the range of 4 to 15 μm, preferably 4 to 9 μm are obtained.
[0055]
  The external addition treatment is a treatment in which an external additive such as silica is mixed with the toner particles (toner base particles) obtained by the classification. For this, a known mixer such as a Henschel mixer or a super mixer is used.
[0056]
  FIG. 1 is a cross-sectional view schematically showing the structure of an example of a kneading apparatus used in the toner manufacturing method of the present invention. In FIG. 1, 101 is a feeder for supplying mixed raw materials, and 102 is a motor. , 103 is a kneading shaft, 104 is a vent hole for deaeration, 105 is a feed screw, 106 is a kneading needing disk, 107 is a seal ring for kneading, 108 is a pineapple ring for kneading, Reference numeral 109 denotes a kneaded product discharge port. Here, the screw 103, the needing disk 106, the seal ring 107, and the pineapple ring 108 are fitted on the kneading shaft 103. A thermocouple (not shown) is installed at the discharge port 109 of the kneaded material, and the discharge temperature (Tmt) is measured here.
[0057]
  The kneader is roughly divided into three kneading blocks B11, B22, and B33. Each block is composed of a first kneading segment whose feed function is its main function and a second kneading segment whose kneading function is its main function. In the first and second kneading segments, a heater is provided for each segment, and kneading settings (Tmn) and (Tmr) can be set in each segment.
[0058]
  The kneading block B11 is composed of 11ra, 11rb, 11rc, and 11rd that are the first kneading segments and 11na that is the second kneading segment. The kneading block B22 includes 22ra that is the first kneading segment and 22na that is the second kneading segment. The second kneading segment 22na is provided with a seal ring 107 at a part thereof, so that the kneaded material can be temporarily retained to improve the kneadability. The kneading block B33 is composed of 33ra which is the first kneading segment and 33na which is the second kneading segment. The second kneading segment 33na is provided with a pineapple ring 108 on the discharge port side thereof, thereby preventing the kneaded material from agglomerating and improving the discharge performance.
[0059]
  2 is a side view showing the configuration of the main part of the kneading shaft of the kneading treatment apparatus shown in FIG. 1, FIGS. 3 and 4 are side and front views of the feed screw shown in FIGS. Is a side view and a front view of the feed screw of the kneading disk shown in FIGS. 1 and 2, FIGS. 7 and 8 are a side view and a front view of the seal ring shown in FIGS. FIG. 2 is a side view and a front view of the pineapple ring shown in FIG. In these drawings, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.
[0060]
  In the kneading block B11, the toner material is fed while being melted by the spiral feed screw 105 (kneading segments 11ra, 11rb, 11rc, 11rd), reaches the kneading segment 11na, and is kneaded by the kneading needing disk 106. Further, in the kneading block B22, the toner material is fed while being melted again by the feed screw 105 having a spiral shape (kneading segment 22ra), reaches the kneading segment 22na, and again by the needing disk 106 and the seal ring 107. Kneaded.
[0061]
  At this time, the outer peripheral speed of the needing disk 106 rotated by the rotation of the kneading shaft 103 is in the range of 225 to 900 mm / s, preferably in the range of 250 to 850 mm / s, more preferably in the range of 350 to 800 mm / s. Set to range. If the outer peripheral speed of the needing disk 106 is lower than 225 mm / s, the toner material is not sufficiently stressed by kneading, and the processing amount is also reduced. The load on the motor increases and the power consumption increases significantly.
[0062]
  The toner obtained by the production method of the present invention includes an image carrier that contains a fixed magnet and the surface thereof moves in a predetermined direction, a hopper that contains toner, and a magnet that contains a predetermined area on the surface of the image carrier. An image carrier that includes a toner collecting electrode roller facing the surface with a predetermined interval and a developing device having a scraper that is in pressure contact with a region different from the predetermined region on the surface of the toner collecting electrode roller, and moves in the predetermined direction An electrostatic latent image is formed on the surface of the body, and the toner contained in the hopper is magnetically attracted to the surface of the image carrier on which the electrostatic latent image is formed by the magnetic force of the fixed magnet. The toner collecting electrode roller collects toner existing on the surface of the image bearing member other than the image portion of the electrostatic latent image, and collects the toner image on the surface of the image bearing member. Form, it is preferably used the toner collected on the surface of the toner collecting electrode roller in an electrophotographic apparatus having a developing system scraping the inside of the hopper by the scraper. This is because, in the toner obtained by the conventional manufacturing method, the additive, particularly the release agent having a low softening point, is not uniformly dispersed in the toner but is unevenly distributed or aggregated. The release agent at the softening point falls off, and the release agent at the low softening point is fused and deposited on the scraper, so that the toner recoverability of the scraper is reduced. Since it is sprinkled on the entire surface of the body, a film of a release agent having a low softening point is formed on the surface of the image carrier, and the image quality is remarkably lowered. This is because the release agent having a low softening point is uniformly dispersed, and the above-described problems do not occur.
[0063]
  The toner obtained by the production method of the present invention can be obtained by inserting a transfer material between an image carrier and a conductive elastic roller, and applying a transfer bias voltage to the conductive elastic roller. The toner image is preferably used in an electrophotographic apparatus including a toner transfer system that transfers a toner image on a transfer material with electrostatic force. Since this toner transfer system is contact transfer, a mechanical force other than electric force acts on the transfer, and the reverse polarity toner adhering to the surface of the photoreceptor that should not be transferred is transferred or passed through. The toner that adheres to the surface of the photoreceptor when not in paper may contaminate the transfer roller surface and the back surface of the transfer paper, but the toner obtained by the production method of the present invention is a binder resin. Since the additive is uniformly and uniformly dispersed therein, when such toner is applied to an image forming apparatus equipped with the toner transfer system, the fluidity of the toner is maintained and the reverse polarity is maintained. No toner is generated, and no filming of the toner or the low softening release agent released from the toner on the surface of the photosensitive member occurs, and contamination of the transfer paper with unnecessary toner particles can be prevented. A. Further, filming of the toner and the released low softening point release agent on the transfer roller surface can be prevented, and this is caused by retransfer of the toner and the released low softening point release agent from the transfer roller surface to the photoreceptor surface. Image defects can also be prevented.
[0064]
  In addition, the toner obtained by the production method of the present invention has a toner image formed on the surface of the image bearing member brought into contact with the surface of the endless intermediate transfer member on the surface of the image bearing member. The primary transfer process for transferring the toner image is repeatedly executed a plurality of times, and thereafter, the overlapping transfer toner images formed on the surface of the intermediate transfer member by the repeated execution of the primary transfer process a plurality of times are collectively transferred onto the transfer material. It is preferably used in an electrophotographic apparatus including a transfer system configured to perform a secondary transfer process. This is because the toner obtained by the production method of the present invention is obtained by uniformly and uniformly dispersing the additive in the binder resin, so that the release agent having a low softening point is dropped from the toner and the intermediate transfer is performed. This is because the film is not filled into the body, and the decrease in transfer efficiency is suppressed. In addition, the uniform and uniform dispersion of the resin fine particles having a low coefficient of dynamic friction reduces the mutual adhesion between the toner particles, and the toner aggregation is alleviated. This is because it is possible to reduce the phenomenon of “missing” that becomes a hole without being transferred.
[0065]
  Further, the toner obtained by the production method of the present invention is suitable for an electrophotographic apparatus equipped with a waste toner recycling system in which toner remaining on the image carrier after the transfer process is collected in the developing apparatus and used again in the developing process. Used for. This is because the toner obtained by the production method of the present invention is obtained by uniformly and uniformly dispersing the additive in the binder resin, so that the toner is collected from the cleaning device to the developing device. Cleaning device, transport pipe that connects the cleaning device and the developing device, and the additive does not fall off even when subjected to mechanical impact inside the developing device, reducing the generation of defective charged toner (particles), and waste toner This is because it is possible to prevent a decrease in toner fluidity and charge amount during recycling and toner filming on the photoreceptor.
[0066]
【Example】
  Hereinafter, the present invention will be described in more detail with reference to examples. Here, the toner was manufactured by the kneading apparatus shown in FIG.
[0067]
  Example 1
  Table 1 shows the formulation of the toner produced in this example.
[0068]
[Table 1]

[0069]
  Table 2 shows the thermal characteristics of the styrene butyl acrylate copolymer used as the binder resin in this example.
[0070]
[Table 2]

[0071]
  In Table 2, TgL (° C) is the glass transition point of the low molecular weight polymer component, MwL is the weight average molecular weight of the low molecular weight polymer component, TgH (° C) is the glass transition point of the high molecular weight polymer component, and MwH is the high molecular weight. The weight average molecular weight of the polymer component, KL / H is the composition ratio of the low molecular weight polymer component and the high molecular weight polymer component, and Tsp (° C.) is the softening point of the whole polymer.
[0072]
  Table 3 shows the set temperature and discharge temperature of each kneading segment in the kneading apparatus shown in FIG. 1 (specifically, PCM43 manufactured by Ikekai Tekko Co., Ltd.). The material supply rate is 40 kg / h, and the peripheral speed in rotation of the kneading shaft is 600 mm / s.
[0073]
[Table 3]

[0074]
  Table 4 shows the dynamic friction coefficient of the low dynamic friction coefficient material used in this example.
[0075]
[Table 4]

[0076]
  Table 5 shows the sample number of the toner sample manufactured in this example, the binder resin used, the kneading conditions, and the low dynamic friction coefficient material.
[0077]
[Table 5]

[0078]
  Table 6 shows image evaluation and fixability evaluation of images obtained by using the toner sample produced in this example, image formation with an electrophotographic copying machine FP-4080 (trade name, manufactured by Matsushita Electric Industrial Co., Ltd.) It is the result of having performed. Development was a two-component system, and the carrier was Cu-Zn-Fe2O3 coated with silicon resin. The fixing evaluation was performed based on the high temperature offset property at a process speed of 140 mm / s (low speed) and the fixing rate at 450 mm / s (high speed). The fixing rate is 10 reciprocal rubbing with a 500 g (φ36 mm) weight wound with “Bencot” (trade name, manufactured by Asahi Kasei Co., Ltd.) for each row of patches with an image density of 1.0 ± 0.2. The density was measured with a Macbeth reflection densitometer and defined by the rate of change. This fixing rate was set to an acceptable level of 75% or more. Further, the offset property was set to an acceptable level of 180 ° C. or higher.
[0079]
  The image evaluation was evaluated based on the image density and the ground cover after the end of the image formation and after the endurance test after 200,000 sheets. The ground cover was judged clearly, and if it was a practically acceptable level, it was judged as acceptable (◯).
[0080]
[Table 6]

[0081]
  As can be seen from Table 6, the toner samples A1, A2, A3, and A4 (example toners) also exhibited good characteristics such as high-temperature offset at low speed, fixing rate at high speed, image density, and ground cover. However, in toner sample B1 (comparative toner), the fixing rate at a high speed was low, and the fogging caused by poor dispersion increased. In toner sample B2 (comparative toner), the offset property was poor, and the fogging that was thought to be caused by poor dispersion increased.
[0082]
  (Example 2)
  Table 7 shows the formulation of the toner sample A5 manufactured in this example. Here, the styrene butyl acrylate copolymer (R-A) used in Example 1 was used as the binder resin, and the kneading conditions were N-1 in Example 1.
[0083]
[Table 7]

[0084]
  FIG. 11 is a cross-sectional view showing the configuration of an electrophotographic apparatus in which the developing system used in this embodiment is a magnetic one-component developing system. In the figure, 201 is an organic photoconductor, in which a charge generating material of τ-type metal-free phthalocyanine (manufactured by Toyo Ink) is dispersed in a polyvinyl butyral resin (ELEC BL-1 manufactured by Sekisui Chemical) on an aluminum conductive support. Charge comprising a layer, polycarbonate resin (Mitsubishi Gas Chemical Z-200), 1,1-bis (P-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene (Anan = T-405) It has a configuration in which transport layers are sequentially stacked. 202 is a magnet fixed coaxially with the photosensitive member 201, 203 is a corona charger for negatively charging the photosensitive member, 204 is a grid electrode for controlling the charging potential of the photosensitive member, and 205 is signal light.
[0085]
  207 is a magnetic one-component toner, 206 is a toner hopper that supplies the magnetic toner 207 to the surface of the photoconductor 201, 208 is a nonmagnetic electrode roller set with a gap from the photoconductor 201, and 209 is installed inside the electrode roller 208. 210, an AC high voltage power source for applying a voltage to the electrode roller 208, 211 a scraper made of a polyester film that scrapes off the toner on the electrode roller, and 212 a smooth toner flow in the toner hopper. It is a damper for preventing crushing between the photosensitive member and the electrode roller that is crushed by its own weight. These constitute a developing device for visualizing the exposed latent image. Here, the electrode roller 208 is for collecting excess toner in the non-image area.
[0086]
  Reference numeral 213 denotes a transfer roller for transferring the toner image on the photosensitive member to paper, and is set so that the surface thereof is in contact with the surface of the photosensitive member 201. The transfer roller 213 is an elastic roller provided with a conductive elastic member around a shaft made of a conductive metal. The pressing force to the photosensitive member 201 is 0 to 2000 g, preferably 500 to 1000 g, per transfer roller 213 (about 216 mm). This was measured from the product of the spring coefficient of the spring for pressing the transfer roller 213 against the photosensitive member 201 and the amount of contraction. The contact width with the photoreceptor 201 is about 0.5 mm to 5 mm. The rubber hardness of the transfer roller 213 is 80 degrees or less, preferably 30 to 40 degrees by the Asker C measurement method (measurement using a block piece, not a roller shape). The elastic roller 213 is placed around the shaft with a diameter of 6 mm.₂By adding a lithium salt such as O 2, the resistance value is 10⁷A foamable urethane elastomer having Ω (electrodes on the shaft and surface and 500 V applied to both) was used. The entire outer diameter of the transfer roller 213 was 16.4 mm, and the hardness was 40 degrees with Asker C. The transfer roller 213 was brought into contact with the photosensitive member 201 by pressing the shaft of the transfer roller 213 with a metal spring. The pressing force was about 1000 g. As the elastic body of the roller, an elastic body made of other materials such as CR rubber, NBR, Si rubber, fluorine rubber, etc. can be used in addition to the foamable urethane elastomer. In addition to the lithium salt, other conductive substances such as carbon black can be used as the conductivity imparting agent for imparting conductivity.
[0087]
  Reference numeral 214 denotes a rush guide made of a conductive member for introducing the transfer paper into the transfer roller 213, and reference numeral 215 denotes a conveyance guide in which the surface of the conductive member is covered with insulation. The entry guide 214 and the conveyance guide 215 are grounded directly or via a resistor. Reference numeral 216 denotes transfer paper, and 217 denotes a voltage generating power source for applying a voltage to the transfer roller 213.
[0088]
  Reference numeral 218 denotes a cleaning blade for scraping off untransferred toner, 219 denotes a cleaning box for storing waste toner, and 223 denotes waste toner.
[0089]
  Although the elastic urethane blade is used as the cleaning blade, the same result is obtained with a fur brush or a conductive metal roller to which a bias is applied.
[0090]
  The magnetic flux density on the surface of the photoreceptor 201 is 600 Gs. Conveyance was improved by increasing the magnetic force inside the electrode roller. In addition, the magnetic pole angle of the magnet 202 shown in the figure is set to 15 degrees. The photosensitive member 201 had a diameter of 30 mm and was rotated at a peripheral speed of 260 mm / s in the direction of the arrow in the figure. The electrode roller 208 had a diameter of 16 mm, and was rotated at a peripheral speed of 40 mm / s in the direction opposite to the traveling direction of the photosensitive member 201 (the arrow direction in the figure). The gap between the photoconductor 201 and the electrode roller 208 was set to 300 μm.
[0091]
  The photosensitive member 201 was charged to −500 V with a corona charger 203 (applied voltage −4.5 kV, grid 204 voltage −500 V). The photosensitive member 201 was irradiated with a laser beam 205 to form an electrostatic latent image. At this time, the exposure potential of the photosensitive member 201 was -90V. On the surface of the photoconductor 201, the toner 207 was adhered in a toner hopper 206 by a magnet. Next, the photosensitive member 201 was passed in front of the electrode roller 208. When the photosensitive member 201 passes through the uncharged region, the electrode roller 208 is supplied with an AC voltage (frequency 1 kHz) of 750 V0-p (peak-to-peak 1.5 kV) obtained by superimposing a DC voltage of 0 V by an AC high voltage power supply 210. Applied. Thereafter, when passing through the photosensitive member 201 charged with −500 V and having an electrostatic latent image written thereon, the electrode roller 208 is 750 V 0 -p (peak-to-peak) with a DC voltage of −350 V superimposed by an AC high voltage power source 210. An alternating voltage of 1.5 kV was applied (frequency 1 kHz). As a result, the toner adhering to the charged portion of the photoconductor 201 was collected by the electrode roller 208, and a negative / positive inverted toner image of only the image portion remained on the photoconductor 201. The toner adhering to the electrode roller 208 rotating in the direction of the arrow was scraped off by the scraper 211, returned again into the toner hopper 206, and used for the next image formation. The toner image thus obtained on the photoconductor 201 is transferred onto a transfer sheet by a transfer roller 213 and then thermally fixed by a fixing device (not shown) to obtain a copy image.
[0092]
  With this electrophotographic apparatus, when the toner sample A5 was used to produce an image, 16 solid black images with a uniform solid density and a density of 1.4 were obtained, with no horizontal line disturbance, toner scattering, or missing characters. An image with extremely high resolution and high image quality that can reproduce the image line of / mm was obtained. A high density image having an image density of 1.4 or more was obtained. There was no ground cover in the non-image area. Furthermore, when a long-term copying test of 10,000 sheets was conducted, there was no toner adhering to the scraper, no toner (release agent) filming on the surface of the photoreceptor, and a high quality comparable to the initial image. A copy image of density and low-level fog was obtained.
[0093]
  (Example 3)
  Table 8 shows the formulation of the toner sample A6 manufactured in this example. Here, the styrene butyl acrylate copolymer (RB) used in Example 1 was used as the binder resin, and the kneading conditions were N-2 in Example 1.
[0094]
[Table 8]

[0095]
  When this sample toner A6 was used to produce an image using the electrophotographic apparatus shown in FIG. 11 used in Example 2, a solid black image was obtained without horizontal line disturbance, toner scattering, and missing characters. A very high-resolution, high-quality image was obtained that reproduced even 16 lines / mm with a density of 1.4. A high density image having an image density of 1.4 or more was obtained. There was no ground cover in the non-image area. Furthermore, when a long-term copying test of 10,000 sheets was conducted, there was no toner adhering to the scraper, no toner (release agent) filming on the surface of the photoreceptor, and a high quality comparable to the initial image. A copy image of density and low-level fog was obtained.
[0096]
  Example 4
  FIG. 12 is a cross-sectional view showing the configuration of the electrophotographic apparatus used in this example. The apparatus of this embodiment has a configuration in which a waste toner recycling mechanism is added to the configuration of the electrophotographic apparatus shown in FIG. That is, the toner remaining after transfer is scraped off by the cleaning blade 218, and the waste toner 223 temporarily stored in the cleaning box 219 is returned to the toner hopper 206 of the developing device by the transport pipe 220.
[0097]
  Using the toner sample A5 produced in Example 2, images were printed out by such an electrophotographic apparatus. As a result, an extremely high-resolution, high-quality image that reproduces 16 lines / mm with a solid black image and a density of 1.4 without any horizontal line disturbances, toner scattering, or missing characters. It was. A high density image having an image density of 1.4 or more was obtained. There was no ground cover in the non-image area. Furthermore, when a long-term copying test of 10,000 sheets was performed while recycling waste toner, there was no decrease in toner fluidity after 10,000 sheets, and a high charge amount was maintained, and toner (release agent) on the photoreceptor was maintained. ) Filming did not occur, and a copy image of high density and low-fogging fog that was inferior to the initial image was obtained. The toner could be recycled well.
[0098]
  (Example 5)
  Images were produced using the toner A6 shown in Example 3 by the electrophotographic apparatus shown in FIG. As a result, an extremely high-resolution, high-quality image that reproduces 16 lines / mm with a solid black image and a density of 1.4 without any horizontal line disturbances, toner scattering, or missing characters. It was. A high density image having an image density of 1.4 or more was obtained. There was no ground cover in the non-image area. Furthermore, when a long-term copying test of 10,000 sheets was performed while recycling waste toner, there was no decrease in toner fluidity after 10,000 sheets, and a high charge amount was maintained, and toner (release agent) on the photoreceptor was maintained. ) Filming did not occur, and a copy image of high density and low-fogging fog that was inferior to the initial image was obtained. The toner could be recycled well.
[0099]
  In Examples 2 to 5 described above, image formation was performed at a process speed of 260 mm / s, but similar good results could be obtained even at process speeds of 140 mm / s and 450 mm / s.
[0100]
  (Example 6)
  Table 9 shows the formulation of the toner sample produced in this example.
[0101]
[Table 9]

[0102]
  Here, the styrene butyl acrylate copolymer (R-A) used in Example 1 was used as the binder resin, the kneading conditions were set to N-1 in Example 1, and a benzidine yellow pigment was used as the yellow colorant for the yellow toner. 5 parts by weight, 6 parts by weight of a nafrole-based insoluble azo pigment as a magenta colorant for magenta toner, and 5 parts by weight of a copper phthalocyanine pigment as a cyan colorant for cyan toner. Further, 20 parts by weight of a polyester resin having an acid value of 20 was added as a charge control agent. In addition, it is preferable to use the polyester resin as a charge control seat in the range of an acid value of 5-40, and it is preferable to add 5-45 weight part with respect to 100 weight part of binder resin.
[0103]
  FIG. 13 is a cross-sectional view showing the configuration of an electrophotographic apparatus for forming a full-color image used in this embodiment. In the figure, reference numeral 1 denotes an exterior casing of a color electrophotographic printer, and the right end face side in the figure is the front face. Reference numeral 1A denotes a printer front plate, and the front plate 1A can be freely opened and closed with a hinge shaft 1B on the lower side with respect to the printer outer casing 1 as shown by a dotted line, and can be raised and closed as shown by a solid line. The internal transfer belt unit 2 is attached to and detached from the printer, and internal inspection and maintenance of the printer, such as when a paper jam occurs, is performed by tilting and opening the front plate 1A to largely release the inside of the printer. The attachment / detachment operation of the intermediate transfer belt unit 2 is designed to be perpendicular to the direction of the rotation axis of the photosensitive member.
[0104]
  The configuration of the intermediate transfer belt unit 2 is shown in FIG. The intermediate transfer belt unit 2 includes a unit housing 2a, a transfer belt 3, a first transfer roller 4 made of a conductive elastic body, a second transfer roller 5 made of an aluminum roller, a tension roller 6 for adjusting the tension of the transfer belt, a transfer belt. A belt cleaner roller 7 for cleaning the toner image remaining on the upper surface, a scraper 8 for scraping off the toner collected on the cleaner roller 7, waste toner reservoirs 9a and 9b for collecting the collected toner, and position detection for detecting the position of the transfer belt Contains the vessel 10. As shown in FIG. 13, the intermediate transfer belt unit 2 is detachably attached to a predetermined storage section in the printer outer casing 1 by opening the printer front plate 1 </ b> A as shown by a dotted line.
[0105]
  The intermediate transfer belt 3 is used by kneading a conductive filler in an insulating resin and forming a film with an extruder. In the present example, a film obtained by adding 5 parts by weight of conductive carbon (for example, ketjen black) to 95 parts by weight of polycarbonate resin (for example, Iupilon Z300, manufactured by Mitsubishi Gas Chemical) was used as the insulating resin. The surface was coated with a fluorine resin. The thickness of the film is about 350 μm and the resistance is about 10⁷-10⁸Ω · cm. Here, the intermediate transfer belt 3 in which a conductive filler is kneaded with polycarbonate resin and used as a film can effectively prevent loosening and accumulation of charge due to long-term use of the intermediate transfer belt. The reason why the surface is coated with fluorine resin is to effectively prevent toner filming on the surface of the intermediate transfer belt due to long-term use.
[0106]
  This transfer belt is made of an endless belt-like semiconductive urethane-based film having a thickness of 100 μm,⁷It is configured to be wound around a first transfer roller 4, a second transfer roller 5 and a tension roller 6 formed of urethane foam subjected to low resistance treatment so as to have a resistance of Ω · cm, and to be movable in the direction of the arrow. Here, the circumferential length of the transfer belt is a length (62 mm) slightly longer than half of the circumferential length of a photosensitive drum (diameter 30 mm), which will be described later, in the longitudinal length (298 mm) of A4 paper, which is the maximum paper size. Is set to 360 mm.
[0107]
  When the intermediate transfer belt unit 2 is mounted on the printer main body, the first transfer roller 4 is pressed into contact with the photoreceptor 11 (shown in FIG. 14) via the intermediate transfer belt 3 with a force of about 1.0 kg. The second transfer roller 5 is pressed against a third transfer roller 12 (shown in FIG. 14) having the same configuration as the first transfer roller 4 via the intermediate transfer belt 3. The third transfer roller is configured to be driven to rotate by the intermediate transfer belt 3.
[0108]
  The cleaner roller 7 is a belt cleaner roller that cleans the intermediate transfer belt 3. This is a configuration in which an AC voltage that electrostatically attracts toner is applied to a metallic roller. The cleaner roller 7 may be a rubber blade or a conductive fur brush to which a voltage is applied.
[0109]
  In FIG. 13, in the center of the printer, four sets of fan-shaped image forming units 17Bk, 17Y, 17M, and 17C for each color of black, cyan, magenta, and yellow constitute an image forming unit group 18, as shown in the figure. It is arranged in an annular shape. Each of the image forming units 17Bk, 17Y, 17M, and 17C is detachable at a predetermined position of the image forming unit group 18 by opening the printer upper surface plate 1C around the hinge shaft 1D. When the image forming units 17Bk, 17Y, 17M, and 17C are properly mounted in the printer, the mechanical drive system and the electric circuit system on both the image forming unit side and the printer side are mutually coupled members (not shown). Are combined through mechanical and electrical integration.
[0110]
  The image forming units 17Bk, 17C, 17M, and 17Y arranged in an annular shape are supported by a support (not shown), and are driven by a moving motor 19 that is a moving means as a whole, and are fixed and do not rotate. It is comprised so that rotation around the shaft 20 of a shape is possible. Each image forming unit can be positioned at an image forming position 21 facing the second transfer roller 4 that sequentially supports the above-described intermediate transfer belt 3 by rotational movement. The image forming position 21 is also an exposure position by the signal light 22.
[0111]
  Each of the image forming units 17Bk, 17C, 17M, and 17Y is composed of the same constituent members except for the developer contained therein, so that the black image forming unit 17Bk will be described for simplifying the description, and for other colors. The description of the unit is omitted.
[0112]
  Reference numeral 35 denotes a laser beam scanner unit disposed on the lower side of the printer outer casing 1 and includes a semiconductor laser, a scanner motor 35a, a polygon mirror 35b, a lens system 35c, and the like which are not shown. The pixel laser signal light 22 corresponding to the time-series electric pixel signal of the image information from the scanner unit 35 is opened on a part of the shaft 20 through an optical path window 36 formed between the image forming units 17Bk and 17Y. Is incident on a fixed mirror 38 in the shaft 20 through the formed window 37, is reflected, enters the image forming unit 17Bk almost horizontally from the exposure window 25 of the image forming unit 17Bk at the image forming position 21, and forms an image. The light passes through the passage between the developer reservoir 26 and the cleaner 34 disposed vertically in the unit and enters the exposure portion on the left side of the photosensitive drum 11 to be scanned and exposed in the direction of the generatrix.
[0113]
  Here, since the optical path from the optical path window 36 to the mirror 38 uses a gap between the adjacent image forming units 17Bk and 17Y, the image forming unit group 18 has almost no wasted space. Further, since the mirror 38 is provided at the center of the image forming unit group 18, it can be constituted by a single fixed mirror, and is simple and easy to align.
[0114]
  Reference numeral 12 denotes a third transfer roller disposed on the inner side of the printer front plate 1A and above the feed roller 39. The printer front plate 1A is disposed at the nip portion where the intermediate transfer belt 3 and the third transfer roller 12 are pressed. A paper transport path is formed so that the paper is fed by a paper feed roller 39 provided at the lower part of the paper.
[0115]
  Reference numeral 40 denotes a paper feed cassette provided so as to protrude outward on the lower side of the printer front plate 1A, and a plurality of paper S can be set simultaneously. 41a and 41b are paper conveyance timing rollers, 42a and 42b are a pair of fixing rollers provided on the inner upper side of the printer, 43 is a paper guide plate provided between the third transfer roller 12 and the pair of fixing rollers 42a and 42b, and 44a and 44b. Is a pair of paper discharge rollers disposed on the paper exit side of the pair of fixing rollers 42a and 42b, 45 is a fixing oil reservoir for storing silicone oil 46 supplied to the fixing roller 42a, and 47 is an oil for applying the silicone oil 46 to the fixing roller 42a. Supply roller.
[0116]
  Each of the image forming units 17Bk, 17C, 17M, and 17Y and the intermediate transfer belt unit 2 is provided with a waste toner reservoir.
[0117]
  The operation will be described below.
[0118]
  Initially, in the image forming unit group 18, as shown in FIG. 13, the black image forming unit 17Bk is at the image forming position 21 as shown. At this time, the photoconductor 11 is in opposed contact with the first transfer roller 4 via the intermediate transfer belt 3.
[0119]
  In the image forming process, black signal light is input to the image forming unit 17Bk by the laser exposure device 35, and image formation with black toner is performed. At this time, the image forming speed of the image forming unit 17Bk (60 mm / s equal to the peripheral speed of the photosensitive member) and the moving speed of the intermediate transfer belt 3 are set to be the same. 4, the black toner image is transferred to the intermediate transfer belt 3. At this time, a DC voltage of +1 kV was applied to the first transfer roller. Immediately after all the black toner images have been transferred, the image forming units 17Bk, 17C, 17M, and 17Y are driven by the moving motor 19 as a whole as the image forming unit group 18 and rotated and moved in the direction of the arrow in the figure. The image forming unit 17C rotates 90 degrees and stops at a position where it reaches the image forming position 21. During this time, the toner hopper 26 and the cleaner 34 other than the photoconductor of the image forming unit are located on the inner side of the rotating arc at the tip of the photoconductor 11, so that the intermediate transfer belt 3 does not contact the image forming unit.
[0120]
  After the image forming unit 17C arrives at the image forming position 21, the laser exposure device 35 inputs signal light to the image forming unit 17C with a cyan signal, as before, and a cyan toner image is formed and transferred. By this time, the intermediate transfer belt 3 makes one rotation, and the writing timing of the cyan signal light is controlled so that the next cyan toner image is in positional alignment with the previously transferred black toner image. During this time, the third transfer roller 12 and the cleaner roller 7 are slightly separated from the intermediate transfer belt 3 so as not to disturb the toner image on the transfer belt.
[0121]
  The same operation as described above was performed for magenta and yellow, and four color toner images were positioned and superimposed on the intermediate transfer belt 3 to form a color image. After the transfer of the last yellow toner image, the four color toner images are collectively transferred by the action of the third transfer roller 12 onto the paper fed from the paper feed cassette 40 at the same timing. At this time, the second transfer roller 5 was grounded, and a DC voltage of +1.5 kV was applied to the third transfer roller 12. The toner image transferred to the paper was fixed by a pair of fixing rollers 42a and 42b. The paper was then discharged out of the apparatus through a pair of discharge rollers 44a and 44b. The remaining transfer toner remaining on the intermediate transfer belt 3 was cleaned by the action of the cleaner roller 7 to prepare for the next image formation.
[0122]
  Next, the operation in the monochrome mode will be described. In the single color mode, first, the image forming unit of a predetermined color moves to the image forming position 21. Next, image formation of a predetermined color and transfer to the intermediate transfer belt 3 are performed in the same manner as before, and this time, after the transfer, continues as it is, onto the sheet fed from the paper feed cassette 40 by the next third transfer roller 12. The image was transferred and fixed as it was.
[0123]
  In this apparatus, an image forming unit having a structure using a specific developing method is used, but an image forming unit having a structure using a conventional developing method can also be used.
[0124]
  When this electrophotographic apparatus was used to produce an image using the manufactured toner sample, 16 solid black images with a uniform density of 1.4 were obtained without horizontal line disturbance, toner scattering, and missing characters. An extremely high-resolution, high-quality image that also reproduced the / mm image line was obtained. A high density image having an image density of 1.4 or more was obtained. There was no ground cover in the non-image area. Further, even in the long-term durability test of 10,000 sheets, both the fluidity and the image density showed a stable characteristic with little change. Also, in the transfer, the void is at a level that causes no practical problem, and the transfer efficiency is 90%. Further, the filming of the toner (release agent) onto the photosensitive member and the intermediate transfer belt was at a level causing no practical problem.
[0125]
【The invention's effect】
  As described above, according to the toner manufacturing method of the present invention, the first kneading segment having the feeding function as the main function and the second kneading segment having the kneading function as the main function are provided. Kneading a toner material containing a binder resin having a specific softening point under a specific kneading temperature setting condition using a split-segment kneader having a plurality of kneading segments that can set the kneading set temperature As a result, a toner in which the additive is dispersed very well in the binder resin and excellent fixing properties, offset resistance, developability, and transfer efficiency can be obtained can be produced with good reproducibility. In particular, a toner capable of obtaining good chargeability, fixing property, and offset resistance can be produced even when used between models with different process speeds. In addition, when applied to an electrophotographic apparatus proposed in Japanese Patent Laid-Open No. 5-72890, which enables downsizing, simplification, and cost reduction of a developing device, a high-quality image with high density and low ground fog is obtained. Toner that can be manufactured can be manufactured. Further, when applied to an electrophotographic apparatus having a transfer system using an intermediate transfer member, it is possible to produce a toner that can prevent hollowing out and scattering and can obtain high transfer efficiency. Further, it is possible to produce a toner capable of preventing the occurrence of filming on a photosensitive member, an intermediate transfer member, etc. even in long-term use. In addition, when applied to an electrophotographic apparatus equipped with a waste toner recycling system, a toner capable of forming a high-quality image over a long period of time without causing a decrease in charge amount and no generation of aggregates. Can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a configuration of an example of a kneading apparatus used in a toner manufacturing method of the present invention.
FIG. 2 is a side view showing a configuration of a main part of a kneading shaft of the kneading treatment apparatus shown in FIG.
FIG. 3 is a side view of the feed screw shown in FIGS.
FIG. 4 is a front view of the feed screw shown in FIGS.
FIG. 5 is a side view of the feed screw of the kneaded needing disk shown in FIGS.
6 is a front view of the feed screw of the kneaded needing disk shown in FIGS.
7 is a side view of the seal ring shown in FIGS.
FIG. 8 is a front view of the seal ring shown in FIGS.
9 is a side view of the pineapple ring shown in FIG. 1. FIG.
10 is a front view of the pineapple ring shown in FIG. 1. FIG.
FIG. 11 is a cross-sectional view showing the configuration of an electrophotographic apparatus in which the developing system used in Example 2 of the present invention is a magnetic one-component developing system.
12 is a cross-sectional view showing a configuration of an electrophotographic apparatus used in Example 4 of the present invention. FIG.
FIG. 13 is a cross-sectional view showing a configuration of an electrophotographic apparatus used in Example 6 of the present invention.
14 is a cross-sectional view showing a configuration of the intermediate transfer belt unit shown in FIG.
FIG. 15 is a cross-sectional view showing a schematic configuration of a color electrophotographic apparatus.
[Explanation of symbols]
  2 Intermediate transfer belt unit
  3 Intermediate transfer belt
  4 First transfer roller
  5 Second transfer roller
  6 Tension roller
  11 photoconductor
  12 Third transfer roller
  15 Spring
  16 roller
  17Bk / 17C / 17M / 17Y Image forming unit
  18 Image forming units
  21 Image forming position
  22 Laser signal light
  35 Laser exposure equipment
  38 mirror
  103 Kneading shaft
  104 Vent hole
  105 Feeding screw
  106 Kneading Needing Disc
  107 Seal ring
  108 Pineapple Ring
  109 Discharge port
  B11, B22, B33 Kneading block
  11ra, 11rb, 11rc, 11rd, 22ra, 33ra First kneading segment
  11na, 22na, 33na Second kneading segment
  202 Fixed magnet contained in the photoconductor
  203 Corona charger
  204 Grid electrode
  206 Toner Hopper
  207 Developer
  208 Electrode roller
  209 Magnet installed inside the electrode roller
  211 scraper
  213 Transfer roller
  214 Entry Guide
  215 Transport guide
  216 transfer paper
  218 Cleaning blade
  219 Waste toner box
  220 Waste toner transport pipe
  223 Waste toner

Claims (16)

A method for producing a toner that is colored resin fine particles by obtaining a kneaded melt of a toner material containing at least a binder resin, a colorant, and a release agent, and then cooling and pulverizing the kneaded melt.
The step of obtaining a kneaded melt of the toner material comprises a first kneading segment whose main function is a feeding function and a second kneading segment whose main function is a kneading function,
It has a plurality of kneading segments that can individually set the temperature of the heating cylinder for each segment,
The first kneading segment and the second kneading segment are mixed so that the material to be kneaded in the plurality of kneading segments is kneaded in the second kneading segment immediately after being kneaded in the first kneading segment. A plurality of kneading blocks in which the kneading segments are arranged adjacent to each other are formed ,
Material to be kneaded from the material supply port provided in the kneading segment at one end of the kneading apparatus is turned on and is configured kneaded melt from a discharge port provided in the kneading segment at the other end of the device are discharged And
The set kneading temperature of the second kneading segment in the kneading block is Tmn (° C.), the set kneading temperature of the first kneading segment is Tmr (° C.), the discharge temperature of the kneaded melt is Tmt (° C.), A toner manufacturing method, wherein the toner material is kneaded so that the following formulas (Equation 1, Equation 2, Equation 3) are simultaneously satisfied , where Tsp (° C.) is a softening point of the binder resin.
[Formula 1] Tmr-30 ° C. ≦ Tmn ≦ Tmr−1 ° C.
[Equation 2] Tmn + 5 ° C. ≦ Tmt ≦ Tmn + 80 ° C.
[Equation 3] Tsp-50 ° C. ≦ Tmr ≦ Tsp 2. The toner material is kneaded so that all of the first kneading segments and all of the second kneading segments in the kneading block simultaneously satisfy the formula (Equation 1, Equation 2, Equation 3). 2. A method for producing the toner according to 1. The toner material is kneaded so that all of the first kneading segments and all of the second kneading segments satisfy the following two expressions (Equation 4 and Equation 5) at the same time. Toner production method.
[ Number 4 ]   Tsp-50 ° C. ≦ Tmn ≦ Tsp
[ Number 5 ]   Tsp + 5 ° C ≦ Tmt ≦ Tsp + 50 ° C 2. The toner production according to claim 1, wherein the peripheral speed of the outermost portion of the kneading member attached to the kneading shaft at the second kneading segment and rotating by rotation of the kneading shaft is in a range of 225 to 900 mm / s. Method. The toner production method according to claim 1, wherein a softening point (Tsp) of the binder resin is in a range of 110 to 160 ° C. The binder resin has a weight average molecular weight in the range of 2500 to 20,000, a low molecular weight polymer component comprising a styrene polymer having a glass transition point of 50 ° C. or higher, a weight average molecular weight of 100,000 or higher, and a glass method for producing a toner according to including claim 1 and a high molecular weight polymer component comprising an acrylic copolymer - styrene with transition point in the range of 50-70 ° C.. The toner material, method for producing a toner according to the dynamic friction coefficient including claim 1 0.3 or less of the fine resin particles. Method for producing a toner according to請Motomeko 1 in the range average particle diameter of 0.1~5μm of the dynamic friction coefficient is 0.3 or less of the resin fine particles. The dynamic friction coefficient of 0.3 or less of the resin fine particles, method for producing a toner of the mounting serial to claim 1 which is polyalkylene fine particles. ^2. The toner production method according to claim 1, wherein after the pulverization, hydrophobic silica is externally added in a range of a BET specific surface area of 50 to 350 m ² / g by adsorption of nitrogen which is surface-treated with silicone oil. The mold release agent is one or two or more of polyalkylene, ethylene bisamide, carnauba wax, montan wax and paraffin wax having a melting point of 80 to 160 ° C. per 1.0 part by weight of the binder resin. The method for producing a toner according to claim 1, wherein 15 parts by weight is added. 2. A toner produced by the production method according to claim 1, wherein the image carrier has a process speed in a range of 140 to 480 mm / s, and is fixed to a toner image transferred to a transfer material by a heat roller fixing method. An electrophotographic apparatus using the apparatus. An image carrier that includes a fixed magnet and whose surface moves in a predetermined direction, a hopper that contains toner, and a toner collection that includes a magnet and a predetermined region of the surface that faces the surface of the image carrier with a predetermined interval An electrode roller and a developing device having a scraper pressed against a region different from the predetermined region on the surface of the toner collecting electrode roller, and forms an electrostatic latent image on the surface of the image carrier that moves in the predetermined direction. After the toner contained in the hopper is magnetically attracted to the surface of the image carrier on which the electrostatic latent image is formed by the magnetic force of the fixed magnet, the image carrier is used by the toner recovery electrode roller. Of the toner adhering to the surface of the toner image is recovered to form a toner image on the surface of the image carrier, and the toner image is formed on the surface of the toner recovery electrode roller. The toner which has been yield comprising a development system scraping the inside of the hopper by the scraper, electrophotographic apparatus, characterized by using a toner produced by the production method according to claim 1. A transfer material is inserted between the image carrier and the conductive elastic roller, and a transfer bias voltage is applied to the conductive elastic roller to transfer the toner image on the image carrier to the transfer material with electrostatic force. An electrophotographic apparatus comprising a toner transfer system and using toner manufactured by the manufacturing method according to claim 1 . A primary transfer process in which the toner image formed on the surface of the image carrier is brought into contact with the surface of the endless intermediate transfer member on the surface of the image carrier and the toner image is transferred to the surface is repeatedly performed a plurality of times. Thereafter, the secondary transfer process is performed in which the duplicate transfer toner image formed on the surface of the intermediate transfer member is collectively transferred to the transfer material by repeatedly executing the primary transfer process a plurality of times. An electrophotographic apparatus comprising the system and using toner manufactured by the manufacturing method according to claim 1 . A waste toner recycling system for collecting toner remaining on the image bearing member after the transfer process in the developing device and reusing it in the developing process, and using the toner manufactured by the manufacturing method according to claim 1. An electrophotographic apparatus characterized by the above.

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