JP4289853B2 - Image forming method - Google Patents

Description

以上の組成を混合及び溶解し、モノマー混合物として準備した。
【００５１】

【００５２】
上記組成をフラスコ中で分散し、窒素置換を行いつつ加熱を開始する。液温が７０℃となったところで、これに６．５６部の過硫酸カリウムを３５０部のイオン交換水で溶解した溶液を投入した。液温を７０℃に保ちつつ、前記モノマー混合物を投入攪拌し、液温を８０℃にあげて５時間そのまま乳化重合を継続した後に液温を４０℃とした後にフィルターで濾過して分散液Ａを得た。こうして、得られた分散液中の粒子径は、平均粒径が０．１６μｍ、固形分のガラス転移点が６０℃、重量平均分子量（Ｍｗ）が１２，０００であり、ピーク分子量は、１１，０００であった。低分子量ポリプロピレンワックスは、重合体中６％含有されており、本固形分の薄片を透過電子顕微鏡にて観察した結果、重合体粒子がワックス粒子を内包化していることを確認した。重合体のＴＨＦ（テトラヒドロフラン）不溶分は実質的にゼロであった。
【００５３】

以上の割合を混合及び溶解し、モノマー混合物として準備した。
【００５４】

【００５５】
上記組成をフラスコ中で分散し、窒素置換を行いつつ加熱を開始する。液温が６５℃となったところで、これに５．８５部の過硫酸カリウムを３００部のイオン交換水で溶解した溶液を投入した。液温を６５℃に保ちつつ、前記モノマー混合物を投入攪拌し、液温を７５℃にあげて５時間そのまま乳化重合を継続した後に液温を４０℃とした後にフィルターで濾過して分散液Ｂを得た。こうして、得られた分散液中の粒子径は、平均粒径が０．１６μｍ、固形分のガラス転移点が６３℃、重量平均分子量（Ｍｗ）が６００，０００であった。炭化水素系ワックスは、重合体中６％含有されており、本固形分の薄片を透過型電子顕微鏡にて観察した結果、ワックス粒子を内包化していることを確認した。重合体のＴＨＦ不溶分は７％であった。
【００５６】

以上を混合し、サンドグラインダーミルを用いて分散し、カーボンブラック分散液Ｃを得た。
【００５７】
前記分散液Ａ３００部、分散液Ｂ１５０部及び分散液Ｃ２５部を、撹拌装置、冷却管及び温度計を装着した１リットルのセパラブルフラスコに投入し撹拌した。この混合液に凝集剤として、１０％塩化ナトリウム水溶液１８０部を滴下し、加熱用オイルバス中でフラスコ内を撹拌しながら５４℃まで加熱した。４８℃で１時間保持した後、光学顕微鏡にて観察すると径が約５μｍである会合粒子が形成されていることが確認された。
【００５８】
その後の融着工程において、ここにアニオン性界面活性剤（第一工業製薬（株）製：ネオゲンＳＣ）３部を追加した後、ステンレス製フラスコを密閉し、磁力シールを用いて撹拌を継続しながら１００℃まで加熱し、３時間保持した。そして、冷却後、反応生成物をろ過し、イオン交換水で十分に洗浄した後、乾燥させることにより、トナー粒子１を得た。
【００５９】
このトナー粒子１００部に対し、ＢＥＴ比表面積が２００ｍ²／ｇである疎水性シリカ０．７部と一次粒子径が８０ｎｍである疎水性酸化チタン０．７部を添加して乾式混合し、重量平均粒径５．０μｍ、ＳＦ２は１４４、ＳＦ２の変動係数は６．３であるトナー１とした。
【００６０】
トナー粒子１及びトナー１のゲルパーミエーションクロマトグラフィー（以下ＧＰＣと呼ぶ）によるピーク分子量は１１，０００、ＴＨＦ不溶分は３％、Ｍｗは２１０，０００である。キャリア粒子の製造例１のキャリア１００部に対し、前記トナー１を５部混合し、二成分現像剤１とした。前記トナー１００部に対し、キャリア粒子の製造例１のキャリア２５部を混合し、補給用現像剤とした。本発明において、分散液中の粒子の粒径は、粒度測定装置（堀場製作所製、ＬＡ−７００）を用いて測定された個数平均粒径である。
【００６１】
本発明において、重合体のＴＨＦを溶媒としたＧＰＣによる分子量分布は次の条件で測定される。
＜ＧＰＣによる分子量分布の測定＞
４０℃のヒートチャンバー中でカラムを安定化させ、この温度におけるカラムに、溶媒としてＴＨＦを毎分１ｍｌの流速で流し、ＴＨＦ試料溶液を約１００μｌ注入して測定する。試料の分子量測定にあたっては試料の有する分子量分布を、数種の単分散ポリスチレン標準試料により作成された検量線の対数値とカウント値との関係から算出した。検量線作成用の標準ポリスチレン試料としては、例えば、東ソー社製或いは昭和電工社製の分子量が１０²〜１０⁷程度のものを用い、少なくとも１０点程度の標準ポリスチレン試料を用いるのが適当である。又、検出器にはＲＩ（屈折率）検出器を用いる。
【００６２】
尚、カラムとしては、市販のポリスチレンジェルカラムを複数本組み合わせるのがよく、例えば、昭和電工社製のshodex GPC KF−８０１、８０２、８０３、８０４、８０５、８０６、８０７、８００Ｐの組み合わせや、東ソー社製のTSKgel Ｇ１０００Ｈ（ＨＸＬ）、Ｇ２０００Ｈ（ＨＸＬ）、Ｇ３０００Ｈ（ＨＸＬ）、Ｇ４０００Ｈ（ＨＸＬ）、Ｇ５０００Ｈ（ＨＸＬ）、Ｇ６０００Ｈ（ＨＸＬ）、Ｇ７０００Ｈ（ＨＸＬ）、TSKgurd columnの組み合わせを挙げることができる。
【００６３】
試料は以下のようにして作製する。試料をＴＨＦ中に入れ、数時間放置した後、十分振とうしＴＨＦとよく混ぜ（試料の合一体が無くなるまで）、更に１２時間以上静置する。その時ＴＨＦ中への放置時間が２４時間以上となるようにする。その後、サンプル処理フィルター（ポアサイズ０．２〜０．５μｍ、例えば、マイショリディスクＨ−２５−２（東ソー社製）等が使用できる。）を通過させたものをＧＰＣの試料とする。又、試料濃度は、樹脂成分が、０．５〜５ｍｇ／ｍｌとなるように調整する。
【００６４】
本発明において、トナー中の樹脂成分のＴＨＦ不溶分及び原料結着樹脂のＴＨＦ不溶分は以下のようにして測定される。
＜ＴＨＦ不溶分の測定＞
結着樹脂及びトナー０．５〜１．０ｇを秤量し（Ｗ１ｇ）、円筒濾紙（例えば、東洋濾紙社製Ｎｏ．８６Ｒ）を入れてソックスレー抽出器にかけ、溶媒としてＴＨＦ２００ｍｌを用いて１０時間抽出し、溶媒によって抽出された可溶成分溶液をエバポレートした後、１００℃で数時間真空乾燥し、ＴＨＦ可溶樹脂成分量を秤量する（Ｗ２ｇ）。トナー中の樹脂成分以外の重さを求める（Ｗ３ｇ）。ＴＨＦ不溶分は下記式から求められる。

【００６５】
本発明においてワックスの融点は、ＤＳＣにおいて測定されるワックスの吸熱ピークの最大ピークのピークトップの温度をもってワックスの融点とする。本発明において、ワックス又はトナーの示差走査熱量計によるＤＳＣ測定では、高精度の内熱式入力補償型の示差走査熱量計で測定することが好ましい。例えば、パーキンエルマー社製のＤＳＣ−７が利用できる。測定方法は、ＡＳＴＭ Ｄ３４１８−８２に準じて行う。本発明に用いられるＤＳＣ曲線は、１回昇温させ前履歴を取った後、温度測定１０℃／ｍｉｎ、温度０〜２００℃の範囲で降温させた後、昇温させた時に測定されるＤＳＣ曲線を用いる。ガラス転移点Ｔｇの測定には、例えば、パーキンエルマー社製のＤＳＣ−７のような高精度の内熱式入力補償型の示差走査熱量計で測定を行う。測定方法は、ＡＳＴＭ Ｄ３４１８−８２に準じて行う。
【００６６】
＜補給用現像剤及び二成分現像剤の製造例２＞
キャリアとして、キャリアの製造例２のキャリアを用いることを除いて、トナー、補給用現像剤及び二成分現像剤の製造例１と同様に、二成分現像剤２と補給用現像剤２を作成した。
【００６７】
＜トナー、補給用現像剤及び二成分現像剤の製造例３＞
・スチレン−ｎ−ブチルアクリレート共重合樹脂
（共重合比８０：２０、Ｍｗ１４，０００） ５０部
・スチレン−ｎ−ブチルアクリレート共重合樹脂
（共重合比８０：２０、Ｍｗ３００，０００） ５０部
・カーボンブラック ７部
・融点１３０℃の低分子量ポリプロピレンワックス２部
・融点７５℃の炭化水素系ワックス ２部
・アゾ鉄化合物 ２部
【００６８】
上記混合物を乾式混合後、溶融混練し、粉砕分級を行いトナー粒子２を得た。このトナー粒子２の１００部に対し、ＢＥＴ比表面積が２００ｍ²／ｇである疎水性シリカ０．７部と数平均一次粒子径が８０ｎｍである疎水性酸化チタン０．７部を添加して乾式混合し、重量平均粒径６．２μｍ、ＳＦ２は１５１、ＳＦ２の変動係数は１３．９であるトナー２を得た。キャリアの製造例２のキャリア１００部に対し、トナー２を５部を混合し二成分現像剤３とし、トナー２の１００部に対し、キャリアの製造例２のキャリア２５部を混合し補給用現像剤３とした。
【００６９】
＜補給用現像剤及び二成分現像剤の製造例４＞
キャリアとして、キャリアの製造例３のキャリアを用いることを除いて、トナー、補給用現像剤及び二成分現像剤の製造例３と同様に、二成分現像剤４と補給用現像剤４を作成した。
【００７０】
＜トナー、補給用現像剤及び二成分現像剤の製造例５＞
トナー、補給用現像剤及び二成分現像剤の製造例３で得られたトナー粒子２を熱球形化し、トナー粒子３を得た。以下、トナー、補給用現像剤及び二成分現像剤の製造例３と同様にして補給用現像剤５及び二成分現像剤５を得た。重量平均粒径６．４μｍ、ＳＦ２は１１５、ＳＦ２の変動係数は３．０である。
【００７１】
実施例１
図１に示す画像形成装置を用いて、以下の評価を行った。使用した像担持体としては、φ３０のアルマイト処理を施したアルミシリンダ上に、ポリアミド樹脂を含有する膜厚０．５μｍ下引き層、ポリビニルブチラール樹脂とフタロシアニン顔料からなる膜厚０．１μｍ電荷発生層、ポリカーボネート樹脂と電荷輸送物質からなる膜厚２０μｍ電荷輸送層を形成し、表面層としては、導電性微粒子とＰＴＦＥ粒子を分散したアクリル系多官能性モノマーを紫外線により硬化させ架橋樹脂とした膜厚３μｍの表面層を形成することにより得られた感光ドラムを用いた。二成分現像剤としては、二成分現像剤１、補給用現像剤としては、補給用現像剤１を用いた。
【００７２】
帯電器１０１として本実施例においては、スコロトロン帯電器とし、現像手段１０４の位置で、−６００Ｖの暗部電位を得るよう調整される。露光手段１０３としては、半導体レーザーを用い、明部露光電位として−１２０Ｖとする。現像手段１０４においては、感光体とマグネットを内包する非磁性スリーブとの間隙を５００μｍとし、二成分現像剤を担持し、該非磁性スリーブには、３ｋＨｚ、Ｖｐｐ２０００Ｖの矩形波の交流電圧を印加し、直流成分を−４５０Ｖとする。
【００７３】
現像手段１０４には、二成分現像剤を２１０ｇチャージし、不図示のトナー濃度検知手段によりトナー濃度を制御する。本実施例においては、１２５ｇの補給用現像剤を補給すると、２５ｇのキャリアが現像機内に補給されることとなり、１２５ｇの補給現像剤の補給に対応し約２６ｇの現像手段中の二成分現像剤を排出して入れ替わることとなる。排出量を調整する手段として、現像手段１０４の側面であって、現像手段１０４内の二成分現像剤の粉面に相当する部分にウインドウを設け、画像形成中であって、補給現像剤を補給しないときに開とし、排出を行う。排出された現像剤は、排出路１１６を通じ排出現像剤貯留手段に貯留される。
【００７４】
このような条件で、印字比率１０％の文字画像を形成し、Ａ４横送りで連続プリントを行う。転写帯電器１０５（本実施例においては、φ１６である導電性ローラーを用い、ローラー転写法とした）より、転写紙上に転写し、転写残余の現像剤はブレードを備えたクリーニング手段１０６によってクリーニングされ、収集される。収集された転写残余の現像剤は、補給用現像剤と共に現像手段１０４に補給される。更に１００枚プリントごとに、約５ｍｍの黒帯び画像を形成し、転写せずにクリーニングを行う。
【００７５】
以上の条件設定において、２３℃相対湿度６０％の環境で、１０万枚の画像プリント試験を行った。評価は以下の項目である。
（１）画像濃度
通常の複写機用普通紙（７５ｇ／ｍ²）にプリントしたベタ画像の濃度をマクベス反射濃度計（マクベス社製）を用いて測定する。
（２）かぶり
反射式濃度計（TOKYO DENSHOKU CO.,LTD社製REFLECTOMETER ODEL TC-6DS）を用いて測定（プリント後の白地部反射濃度平均値をＤｓ、プリント前の用紙の反射濃度平均値をＤｒとした時のＤｓ−Ｄｒをかぶり量とした）した。（かぶり量２％以下は、実質的にかぶりの無い良好な画像であり、５％を超えるとかぶりの目立つ不鮮明な画像である。）
【００７６】
（３）細線再現性
約２ｍｍ角の「電」の文字を３０倍に拡大し、以下の評価基準に従い評価を行った。
Ａ：文字ラインがかすれている。
Ｂ：文字ラインにやや細りが見られる。
Ｃ：文字ラインがシャープである。
Ｄ：文字ラインにやや太りが見られる。
Ｅ：文字がつぶれている。
（４）像担持体スクラッチ状傷
（５）像担持体磨耗による画像不良
以上の結果を下記表１に示す。
【００７７】
実施例２
二成分現像剤としては、二成分現像剤２、補給用現像剤としては、補給用現像剤２を用いた以外は、実施例１と評価を同様に行った。１０万枚目に、感光体に微かにスクラッチ状の傷を生じた以外は、問題のない結果であった。以上の結果を下記表１に示す。
【００７８】
実施例３
二成分現像剤としては、二成分現像剤３、補給用現像剤としては、補給用現像剤３を用いた以外は、実施例１と評価を同様に行った。１０万枚目に、感光体に軽微なスクラッチ状の傷を生じ、又、かぶりも若干増加した以外、問題のない結果であった。以上の結果を下記表１に示す。
【００７９】
実施例４
二成分現像剤としては、二成分現像剤３、補給用現像剤としては、補給用現像剤３を用い、１００枚プリントごとに、約５ｍｍの黒帯び画像を形成しなかったこと以外は、実施例１と評価を同様に行った。５万枚目に、感光体に軽微なスクラッチ状の傷を生じ、又、１０万枚目にかぶりも若干増加し、スクラッチ状の傷を生じたが、感光体の磨耗については問題のない結果であった。以上の結果を下記表１に示す。
【００８０】
実施例５
二成分現像剤としては、二成分現像剤５、補給用現像剤としては、補給用現像剤５を用い、１００枚プリントごとに、約５ｍｍの黒帯び画像を形成しなかったこと以外は、実施例１と評価を同様に行った。結果を下記表１に示す。
【００８１】
参考例１
二成分現像剤としては、二成分現像剤４、補給用現像剤としては、補給用現像剤４を用い、１００枚プリントごとに、約５ｍｍの黒帯び画像を形成しなかったこと以外は、実施例１と評価を同様に行った。８万枚目に、感光体磨耗に起因する画像不良が現れたので、評価を打ち切った。以上の結果を下記表１に示す。
【００８２】
比較例１
二成分現像剤としては、二成分現像剤４、補給用現像剤としては、補給用現像剤４を用い、１００枚プリントごとに、約５ｍｍの黒帯び画像を形成しなかったこと及び、像担持体として、導電性微粒子とＰＴＦＥ粒子を分散したアクリル系多官能性モノマーを紫外線により硬化させ架橋樹脂とした膜厚３μｍの表面層を形成せず、電荷輸送層を２３μｍとした以外は、実施例１と評価を同様に行った。４万枚目に感光体磨耗に起因する画像不良が現れたので評価を打ち切った。以上の結果を下記表１に示す。
【００８３】

【００８４】
【発明の効果】
本発明の構成によれば、長寿命感光体を用い微細なトナーを用いた場合でも、高精細な画像を長期にわたり、メンテナンス作業が不要な状態で達成することが可能となり、クリーニングにより収集された転写残余の現像剤を再利用した場合においても、現像特性が劣化せず、感光体への現像剤成分の付着を防止し、長期にわたり高精細な画像を得ることができる。
【図面の簡単な説明】
【図１】本発明の画像形成方法を説明する図。
【符号の説明】
１０１：帯電器
１０２：像担持体（感光体）
１０３：露光手段
１０４：現像手段
１０５：転写帯電器
１０６：クリーニング手段
１０７：帯電前露光手段
１０８：転写材搬送ベルト
１０９：定着器
１１０：転写材搬送ガイド
１１１：レジストローラー
１１２：現像剤搬送路
１１３：現像剤貯留手段
１１４：現像剤補給ボトル
１１５：補給路
１１６：排出路
１１７：排出現像剤貯留手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming method used in a copying machine, a printer, a facsimile, or the like, and more particularly to an electrophotographic method, and replenishes a replenishing developer as necessary, and discharges the developer as necessary from the developing means. The latent image on the carrier is developed by a developing means having a two-component developer composed of carrier and toner to form a developed image, transferred, and the developer remaining on the image carrier is cleaned, The present invention relates to an image forming method which is supplied to a developing unit and reused.
[0002]
[Prior art]
In an electrophotographic image forming apparatus, a uniformly charged image forming body is subjected to image exposure to form a latent image, the latent image is developed into a toner image, and then the toner image is transferred to a recording material such as recording paper. Transferring to is performed. When the transfer material carrying the toner image passes through the fixing device, the toner is fixed on the transfer material. In developing a latent image, a one-component or two-component development method is used, and the development method is adopted in accordance with these characteristics. In two-component development, it is said to be excellent in durability.
[0003]
On the other hand, the toner in the two-component developing machine is consumed and replenishment for the shortage is performed with new toner. However, since the carrier is used continuously, the development characteristics deteriorate due to the deterioration of the carrier, and the regular There is a problem that the work of replacing the developer in the two-component developing machine occurs, and the replenishment toner and the carrier are replenished at a constant ratio, and the carrier in the developing machine whose developing performance is lowered is gradually replaced with a new carrier ( A proposal has been made to eliminate the need for such maintenance work (referred to as trickle development) (see Patent Document 1).
[0004]
Also proposed is an image forming device that removes paper dust and the like by cleaning toner remaining on the transfer and reusing the cleaned toner, using trickle development as the development method, and collecting the carrier in the developer from the top of the developer. (See Patent Document 2). However, in this method, it is speculated that the influence of paper dust can be removed, but in particular, when using a long-life photoconductor with a high surface hardness and maintaining a high-definition image for a long time using fine toner, Insufficient and needs further improvement.
[0005]
The present invention has been made in view of the above, and makes it possible to achieve a high-definition image over a long period of time without using maintenance work, using a long-life photoreceptor and a fine toner. is there.
[0006]
[Patent Document 1]
Japanese Patent Publication No. 2-21591
[Patent Document 2]
JP 2001-194908 A
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an image forming method capable of achieving a high-definition image over a long period of time and without requiring maintenance work even when a long-life photoconductor and a fine toner are used. Is to provide.
Another object of the present invention is to prevent the development characteristics from deteriorating even when the developer remaining after transfer collected by cleaning is reused, and to prevent the adhesion of the developer component to the photoconductor. An object is to provide an image forming method capable of obtaining a high-definition image.
[0008]
[Means for Solving the Problems]
  The above object is achieved by the present invention described below. That is, the present invention forms a latent image on an image carrier, develops the latent image with a developing unit using a two-component developer containing toner and carrier, and supplies the developer with a replenishment developer as necessary. In the image forming method, the developer is discharged from the developing unit as necessary, the developed image is transferred, and the residual transfer developer remaining on the image carrier is cleaned.
  The replenishment developer contains a carrier,
  The carrier has a volume 50% diameter (D50: unit μm), a volume 5% diameter (D5: unit μm), and a volume 16% diameter (D16: unit μm) in the following relationship:
    30 μm ≦ D50 ≦ 40 μm
    0.50 ≦ D5 / D50
    0.65 ≦ D16 / D50
  The image carrier contains a resin having a crosslinked structure on the surface.,
  UpProvided is an image forming method characterized in that the transfer residual developer that has been cleaned and collected is supplied to the developing means and reused.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. An example of the image forming method of the present invention will be described with reference to FIG. The charger 101 uniformly charges the image carrier (photoreceptor) 102 from which the history has been erased by the pre-charging exposure means 107, and forms an electrostatic latent image by the exposure means 103 such as a laser. The electrostatic latent image is converted into a developed image by a developing unit 104 having toner and a carrier, and the developed image is transferred to a transfer material supplied from a resist roller 111 and a transfer material conveyance guide 110 by a transfer charger 105, and a transfer material conveyance belt is obtained. The toner image is fixed to the fixing device 109 by 108.
[0010]
The transfer residual developer remaining on the image carrier 102 is cleaned by the cleaning means 106. The developer remaining after the transfer that has been cleaned and collected is supplied to the developer storage unit 113 via the developer transport path 112 for the transfer residue. The developer is supplied from a developer supply bottle 114 having a supply developer to the developer storage means 113. In the developer storage unit 113, the replenishment developer and the developer collected after transfer are mixed and supplied to the development unit 104 through the replenishment path 115, and the cleaned and collected developer is recycled. Used. The developer discharged from the developing means is stored in the discharged developer storing means 117 through the discharge path 116.
[0011]
In addition to corona chargers such as corotrons and scorotrons, the charger used in the present invention is used by placing a conductive roller, a fur brush, a magnetic brush or the like in contact or non-contact. As the exposure means, when a latent image is formed digitally, a device equipped with a semiconductor laser, an LED, a liquid crystal shutter, or the like is used. In order to achieve high definition, it is preferable to have a resolution of 600 dpi or more.
[0012]
In the developing means, a two-component developing method is adopted, but the carrier used as the two-component developer or the replenishing developer is preferably one whose particle size distribution satisfies the following relational expression.
25 μm ≦ D50 ≦ 50 μm
0.50 ≦ D5 / D50
0.65 ≦ D16 / D50
If D50 is less than 25 μm, the amount of carrier adhering to the image carrier increases and the image tends to deteriorate, and if it exceeds 50 μm, high definition may not be sufficiently achieved. More preferably, D50 is 30 μm or more and 45 μm or less. More preferably, it is 30 μm or more and 40 μm or less.
[0013]
In the image forming method of the present invention, a carrier having a small particle size adheres to the photoconductor, and is involved in transfer and cleaning. Since the carrier is supplied and reused, the carrier having a small particle diameter is collected by the cleaning member even when consumed, and returns to the developing means again. Therefore, it always exists in the developing means and is always supplied at a certain rate on the photosensitive member. Such a phenomenon peculiar to the image forming method of the present invention causes a problem in the photoreceptor.
[0014]
In such an image forming method, if D5 / D50 is less than 0.50, the load on the cleaning member and the surface of the image carrier increases during cleaning, and the wear amount of the photosensitive member tends to increase. If D50 is less than 0.65, the surface of the image carrier tends to generate scratches on the surface of the image carrier during cleaning. In particular, when a contact type is used as the transfer member, the image carrier tends to be more easily damaged, and it is preferable to use a carrier having the above particle size distribution. More preferably, D5 / D50 is 0.55 or more and D16 / D50 is 0.70 or more.
[0015]
The magnetic properties of the carrier are 8.0 × 10^FiveSaturation magnetization at A / m is 41 to 100 Am²What is / Kg is preferably used. 41 Am²If it is less than / Kg, adhesion of the carrier to the image bearing member may increase, resulting in an increase in scratches.²If it exceeds / Kg, the magnetic brush becomes hard and the image quality may be deteriorated. More preferably 45-80Am²/ Kg.
[0016]
The carrier used in the present invention is preferably magnetite or ferrite particles. It is also one of preferred forms to use magnetite or ferrite powder in a form dispersed in resin. As a composition of a ferrite, what contains metal elements, such as copper, zinc, manganese, magnesium, iron, lithium, strontium, barium, is used suitably. Furthermore, the carrier used in the present invention is preferably surface-coated with a silicone resin, a fluorine resin, an acrylic resin or the like. Among these, those using a silicone resin are particularly preferably used.
[0017]
These magnetite or ferrite particles are obtained by firing the raw material forming the magnetite or ferrite particles, and are produced by the following production method as an example. Raw materials composing them (calcined if necessary), water (deionized if necessary), a dispersant, and if necessary, a binder resin are made into a slurry by a disperser. The slurry is granulated with a spray dryer and then sintered in a preferable firing atmosphere to form particles. In order to obtain a preferable carrier of the present invention, for example, it can be obtained by carefully applying a method such as precise classification in these steps.
[0018]
When performing surface coating, it is performed using a wet coating method (for example, dip coating method, fluidized tank drying method, etc.), a dry coating method (method of attaching resin to the surface with mechanical energy), or the like. . The two-component developer used in the present invention is preferably prepared by mixing 1 to 20 parts by mass of toner with respect to 100 parts by mass of carrier, and the replenishment developer has a carrier with respect to 100 parts by mass of toner. It is preferably prepared by mixing 1 to 20 parts by mass.
[0019]
A known toner can be used as the developer toner, but the following toner is preferably used. The toner component of the developer remaining after transfer that has been cleaned and collected is slightly inferior in the tribocharging ability. Furthermore, since it needs to be transported from the cleaning means to the developing means, a load is easily applied to the surface. It is the wax component contained in the toner that is most affected by this type of load, and it is particularly preferable to contain a wax in order to maintain a preferable toner mode of improving the fixability. When wax exists on the surface of the toner particles, it becomes a problem. The wax is accumulated in the developing means due to the deterioration of the developing performance, or the wax returns to the developing means without being transferred even if developed, so that the developing means develops. The wax may not be sufficiently removed by discharging the agent.
[0020]
The inventors have found that the following toner is a preferable configuration for such a problem to be solved. That is, by using a toner containing toner particles produced by aggregating and fusing a plurality of particles in which a polymer obtained by polymerizing monomers is present on the wax surface in an aqueous medium, the toner surface It is possible to effectively reduce deterioration of the developer in the developing means. As a preferred example of producing particles in which a polymer obtained by polymerizing a monomer is present on the surface of a wax in an aqueous medium, for example, a polymerizable monomer and a polymerization initiator are dispersed in a dispersion in which wax fine particles are dispersed. It is mentioned that it is produced by adding and polymerizing wax fine particles as seeds.
[0021]
Further, when the SF2 of the toner is 120 to 170 and the coefficient of variation of SF2 is 4.0 to 8.0, the cleaning device can be set at a setting level that does not place a load on the toner, so that toner deterioration due to the load is small. It can be suitably used in the image forming method of the present invention. If SF2 is less than 120, the toner tends to slip through unless the linear pressure of the cleaning blade is increased, and if it exceeds 170, the unevenness of the toner becomes large, so that the toner tends to become fine powder when subjected to a load. It is in. Furthermore, when the coefficient of variation is less than 4.0, that is, when trying to align the shapes, the sphericity increases, and it is difficult to make SF2 less than 120, and when it exceeds 8.0, the abundance of irregularly shaped particles increases. Therefore, when the developer is reused, it becomes a factor for promoting the deterioration of the toner.
[0022]
In the present invention, SF2 (perimeter length)²This is a shape parameter represented by / projected area / 4π, and expresses irregularities on the surface of the particle. Using a scanning electron microscope, take a photograph of a toner particle with a horizontal chord length of 3 or more magnified 500 times, such as Nireco's image analyzer (Luzex III) or "SCANNING IMAGE ANALYSER" (manufactured by JEOL Ltd.) The photographic image is analyzed using an image analyzer. At this time, SF2 of the present invention is measured by the above calculation formula using 500 toner particles. In the present invention, the average value is SF2, the standard deviation of the 500 SF2s is obtained, and the average deviation value of SF2 is obtained as the variation coefficient of SF2.
[0023]
That is, in the present invention, the toner is lightly loaded by regulating the shape of the toner to suppress the deterioration of the toner, suppress the deterioration by the action of the toner itself by a specific manufacturing method, and have a specific particle size distribution. Is used to achieve a long life in an image forming method in which a photoreceptor having a specific surface layer is used and a developer cleaned by their synergistic effect is reused.
[0024]
As a method for producing such toner particles, for example, a method in which a wax is dissolved or dispersed in a vinyl monomer and then suspended and polymerized in water, or a vinyl monomer is added and emulsified in a wax dispersion to polymerize. In this method, a resin dispersion containing wax is encapsulated to obtain toner particles by aggregating and fusing the resin particles.
[0025]
As the wax, those having a melting point of 60 to 160 ° C. are preferably used, and as the low melting point wax, those having a melting point of 60 to 120 ° C. are preferably used. In particular, when the temperature is 60 to 90 ° C., the effect on the low-temperature fixability is remarkable, and thus a more preferable embodiment of the toner is obtained. As the wax used in the present invention, known waxes can be used, which can be appropriately selected from the melting points.
[0026]
Specifically, aliphatic hydrocarbon waxes (low molecular weight polyethylene, low molecular weight polypropylene, paraffin wax, Fischer-Tropsch wax, etc.), aliphatic hydrocarbon wax oxides, plant waxes (candelilla wax, carnauba wax, etc.) ), Animal waxes (such as beeswax, lanolin, etc.), mineral waxes (such as ozokerite, ceresin, petrolactam, etc.), waxes containing fatty acid esters (behenyl behenate, montanate, stearyl stearate, etc.), saturated or Unsaturated fatty acids (palmitic acid, stearic acid, eleostearic acid, valinalic acid), saturated or unsaturated alcohols with long-chain alkyls (stearyl alcohol, eicosyl alcohol, behenyl alcohol, etc.), polyhydric alcohols (sorbitol Etc.), aliphatic or unsaturated or aromatic amides (linoleic acid amide, oleic acid amide, methylene bis-stearic acid amide, ethylene bis-oleic acid amide, m-xylene bis-stearic acid amide, etc.), fatty acid metal salts (calcium laurate) Zinc stearate, magnesium stearate, etc.), silicone having an alkyl group, and a wax obtained by grafting an aliphatic hydrocarbon wax with a vinyl monomer such as styrene or acrylic acid.
[0027]
Preferred waxes include polyolefins obtained by radical polymerization of olefins under high pressure; polyolefins obtained by purifying low molecular weight by-products obtained during polymerization of high molecular weight polyolefins; polymerized using catalysts such as Ziegler catalysts and metallocene catalysts under low pressures Polyolefins; Polyolefins polymerized using radiation, electromagnetic waves or light; Low molecular weight polyolefins obtained by thermally decomposing high molecular weight polyolefins; Paraffin wax, microcrystalline wax, Fischer-Tropsch wax; Jindole method, Hydrocol method, Age method Synthetic hydrocarbon wax synthesized by the following: a synthetic wax having a compound having one carbon atom as a monomer, a hydrocarbon wax having a functional group such as a hydroxyl group or a carboxyl group; a hydrocarbon wax and a functional group A mixture of wax; styrene these waxes as a matrix, maleic acid ester, acrylate, methacrylate, a graft modified wax to the such vinyl monomers of maleic acid.
[0028]
In addition, these waxes have a sharp molecular weight distribution using a press perspiration method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a melt liquid crystal method, low molecular weight solid fatty acids, low molecular weight solids. An alcohol, a low molecular weight solid compound, and other impurities are preferably used.
[0029]
As the external additive used in the toner of the present invention, known inorganic fine powder or resin particles are used. Preferably, inorganic particles having a number average primary particle diameter of 50 to 200 nm are present on the surface of the toner particles. Toner is preferably used. This is because the external additive having the particle diameter has an effect of relieving stress on the toner particles. Such inorganic fine particles are preferably contained in an amount of 0.1 to 5.0% by weight, more preferably 0.2 to 3.0% by weight, based on the toner.
[0030]
In addition, inorganic fine powders of silica, alumina, titania or double oxides thereof can be used to improve the charging stability, developability, fluidity and storage stability of the toner, which is one of preferred embodiments. These inorganic particles are preferably hydrophobized with a silane coupling agent, a titanium coupling agent, silicone oil or the like.
[0031]
Further, the following external additives are also used depending on the purpose. For example, lubricant powder such as Teflon (registered trademark) powder, zinc stearate powder, polyvinylidene fluoride powder; abrasive such as cerium oxide powder, silicon carbide powder, strontium titanate powder; for example, titanium oxide powder, aluminum oxide powder, etc. A small amount of anti-caking agent, or a conductivity-imparting agent such as carbon black powder, zinc oxide powder or tin oxide powder, or a reverse polarity organic fine particle or inorganic fine particle as a developability improver. You can also.
[0032]
In the present invention, in order to realize a high-definition image, preferable results can be obtained by using a toner for two-component developer or replenishment developer having a weight average particle diameter of 3.0 to 6.0 μm. More preferably, it is 3.5-5.5 micrometers. If the weight average particle diameter is less than 3.0 μm, there are many difficulties in development and a sufficient image may not be obtained.
[0033]
As the image carrier used in the present invention, it is preferable to use an image carrier having a cross-linked structure on its surface layer because the amount of wear is small and the replacement frequency can be minimized. However, in order to prevent the toner from slipping out during cleaning, it is necessary to set the cleaning to a rather strong level.Therefore, the carrier promotes the wear of the surface of the image carrier or scratches may be scratched. It is easy to do. Further, when a high-definition image is taken into consideration, a toner having a small particle size is used, and therefore, the load on cleaning tends to further increase.
[0034]
As a further preferred embodiment of the present invention, a wax in an aqueous medium is used in order to prevent toner deterioration of the transfer residual developer and to effectively prevent contamination (filming and the like) due to toner components on the image carrier. It is preferable to use a toner containing toner particles containing particles obtained by allowing a polymer obtained by polymerizing a monomer to be present on the surface, and the number average primary particle diameter is 50 to 200 nm on the toner particle surface. A toner containing particles is more preferably used.
[0035]
As a solving means from the image forming method for solving such a problem, a step of developing the toner of the developing means on the image carrier and cleaning it without transferring it is included. Such toner reduces the load on cleaning, alleviates the deterioration of the residual toner, and does not waste toner because it is reused.
[0036]
In FIG. 1, corona charging is used as transfer means. In addition, a conductive roller to which a bias is applied, a transfer belt, or the like can be used. When these are used in a contact state, generation of ozone can be suppressed as much as possible, which is a preferable configuration for the image forming method of the present invention. An intermediate transfer member can also be used.
[0037]
An elastic blade is preferably used as the cleaning member. Other methods such as fur brush cleaning and roller cleaning can also be employed. The cleaning means includes means for transporting the transfer residual developer collected by the cleaning member and transporting it to the transfer residual developer transport path 112. The conveying means preferably uses a screw or the like. In another preferred embodiment, a developer having an agitation member that agitates the developer remaining in the transfer in the cleaning means and guides the developer to the conveying means is also a preferable embodiment.
[0038]
As a replenishment method of the replenishment developer, a method using a developer hopper provided in the main body and a cylindrical container provided with a spiral toner guide groove on the inner surface of the peripheral wall described in JP-A-2000-352840, for example, are used. And a method of rotating and replenishing the cylindrical container. In order to facilitate the replenishment mechanism and save space, it is preferable to replenish using the cylindrical container.
[0039]
FIG. 1 shows a more preferable configuration of the present invention in which the replenishment developer and the residual developer collected by the cleaning member are stored, mixed, and supplied to the developing unit. If not, the replenishment developer and the residual developer collected by the cleaning member may be supplied independently or together to the developing means. In the developer storing means, a stirrer for stirring is preferably provided, and the developer is supplied to the developing means by a screw or an air pump.
[0040]
The developer discharged from the developing means is stored in the discharged developer storing means 117 through the discharge path 116. As an example of a specific method for discharging the developer from the developing means, developer powder is developed inside the developing means. There is a configuration in which a window that can be opened and closed is provided at a location corresponding to the body surface, and is opened as needed to discharge the developer. The discharged developer is stored in the discharged developer storage means 117 and discarded as necessary or put into a reproduction process if possible.
[0041]
As an image carrier used in the present invention (for example, in electrophotography, an image carrier is a so-called photoreceptor, and a photosensitive layer is formed on a conductive substrate), the surface layer is crosslinked. It has a structure. A cross-linked surface layer can be formed after forming a charge generation layer and then a charge transport layer on a conductive substrate, and a cross-linked surface after forming a charge transport layer and then a charge generation layer on a conductive substrate. A layer can be formed. It is also possible to form a crosslinked surface layer after forming a layer containing a charge transport material and a charge generation material.
[0042]
Specific examples of the surface layer include an epoxy resin, a polyester resin, a polyamide resin, a polystyrene resin, an acrylic resin, a silicone resin, and the like, and have a crosslinked structure. The production method is preferably a production method in which each monomer constituting each resin is formed by forming a film by a method such as dipping or spray coating with a monomer having a polyfunctional group, followed by polymerization, crosslinking, and curing. Used.
[0043]
For example, as a silicone type, a resin layer having a crosslinked structure can be formed using a composition of a curable organosilicon compound and the like and a reactive charge transporting compound having reactivity with the organosilicon compound. It can also be formed by curing an acrylic polyfunctional monomer in which conductive fine particles are dispersed. More preferably, when a compound having lubricity is contained in the surface layer, the cleaning load can be reduced. Examples of the compound having lubricity include fluororesin particles such as PTFE, low melting point wax and the like. Further, if necessary, silica, metal oxide particles and the like can be contained to enhance the strength of the surface layer.
[0044]
In the present invention, the particle size distribution of the carrier is measured as follows. Using a laser diffraction particle size distribution measuring device HELOS (manufactured by JEOL Ltd.), 0.5 μm is the minimum value, and the range of 1.80 to 350 μm is measured by 31 logarithmic division, and the volume is 50% diameter (D50: unit μm) ), 5% diameter (D5: unit μm) and 16% volume (D16: unit μm).
[0045]
The particle size and particle size distribution of the toner can be measured by various methods such as Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, Coulter Multisizer (manufactured by Coulter Inc.) is used. It was. An interface (manufactured by Nikka) and a personal computer for outputting the number distribution and volume distribution are connected, and a 1% NaCl aqueous solution is prepared using first-grade sodium chloride as the electrolyte. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume distribution is measured by measuring the volume and number of toners of 2 μm or more using the 100 μm aperture as the aperture by the Coulter Multisizer. And the number distribution. Then, a volume-based volume average particle diameter (DV: the median value of each channel is a representative value of the channel) and a weight average particle diameter (D4) obtained from the volume distribution of the present invention are obtained.
[0046]
【Example】
  Next, the exampleReference examplesThe present invention will be specifically described with reference to comparative examples. In the text, “parts” and “%” are based on mass unless otherwise specified.
<Production Example 1 of Carrier Particle>
  CuO 21 mol%, ZnO 25 mol% and Fe₂O_Three  54 mol% is mixed with deionized water, a dispersant and polyvinyl alcohol to form a slurry. The slurry is granulated by a spray drier, passed through a sieve having an opening of 74 μm, and particle size adjustment is performed by collecting sieves having an opening of 32 μm. Furthermore, it fired in 1,100 degreeC atmosphere and obtained the ferrite particle. The ferrite particles were passed three times under the condition of 53 μm openings and 32 μm on openings to obtain ferrite particles having a D50 of 33.9 μm.
[0047]
100 parts of the obtained ferrite particles are immersed in a solution obtained by dissolving 2 parts of silicone resin and 0.4 parts of aminosilane in 50 parts of toluene, stirring at 120 ° C. and removing the solvent. Curing was performed in a controlled oven for 1 hour. Thereafter, the particle size was adjusted by passing through a sieve having an opening of 74 μm and collecting sieves having an opening of 32 μm. D50 is 35.2 μm, D16 is 25.4 μm, D5 is 19.7 μm, D5 / D50 is 0.56, and D16 / D50 is 0.72. Magnetic properties are 8.0 × 10^FiveSaturation magnetization at A / m is 58 Am²/ Kg.
[0048]
<Production Example 2 of Carrier Particle>
Ferrite particles were obtained in the same manner as in Production Example 1 for carrier particles. The ferrite particles were passed twice under the condition of 53 μm openings and 32 μm on openings to obtain ferrite particles having a D50 of 33.1 μm. 100 parts of the obtained ferrite particles are immersed in a solution obtained by dissolving 2 parts of silicone resin and 0.4 parts of aminosilane in 50 parts of toluene, stirring at 120 ° C. and removing the solvent. Curing was performed in a controlled oven for 1 hour. Thereafter, the particle size was adjusted by passing through a sieve having an opening of 74 μm and collecting sieves having an opening of 32 μm. D50 is 34.5 μm, D16 is 23.4 μm, D5 is 18.3 μm, D5 / D50 is 0.53, and D16 / D50 is 0.68. Magnetic properties are 8.0 × 10^FiveSaturation magnetization at A / m is 58 Am²/ Kg.
[0049]
<Manufacture example 3 of carrier particles>
Ferrite particles were obtained in the same manner as in Production Example 1 for carrier particles. The ferrite particles were passed once under the condition of an aperture of 53 μm and an opening of 53 μm and a ferrite particle having a D50 of 32.7 μm was obtained. 100 parts of the obtained ferrite particles are immersed in a solution obtained by dissolving 2 parts of silicone resin and 0.4 parts of aminosilane in 50 parts of toluene, stirring at 120 ° C. and removing the solvent. Curing was performed in a controlled oven for 1 hour. Thereafter, the particle size was adjusted by passing through a sieve having an aperture of 74 μm and collecting sieves having an aperture of 37 μm. D50 is 33.7 μm, D16 is 21.2 μm, D5 is 16.2 μm, D5 / D50 is 0.48, and D16 / D50 is 0.63. Magnetic properties are 8.0 × 10^FiveSaturation magnetization at A / m is 58 Am²/ Kg.
[0050]

The above composition was mixed and dissolved to prepare a monomer mixture.
[0051]

[0052]
The above composition is dispersed in a flask, and heating is started while performing nitrogen substitution. When the liquid temperature reached 70 ° C., a solution prepared by dissolving 6.56 parts of potassium persulfate with 350 parts of ion-exchanged water was added thereto. While maintaining the liquid temperature at 70 ° C., the monomer mixture was added and stirred, the liquid temperature was raised to 80 ° C. and emulsion polymerization was continued for 5 hours. The liquid temperature was adjusted to 40 ° C. and filtered through a filter. Got. Thus, the particle diameter in the obtained dispersion was 0.16 μm in average particle diameter, 60 ° C. in glass transition point of solid content, 12,000 in weight average molecular weight (Mw), and 11 in peak molecular weight. 000. The low molecular weight polypropylene wax contained in the polymer was 6%, and as a result of observing a thin piece of the solid content with a transmission electron microscope, it was confirmed that the polymer particles included the wax particles. The THF (tetrahydrofuran) insoluble content of the polymer was substantially zero.
[0053]

The above proportions were mixed and dissolved to prepare a monomer mixture.
[0054]

[0055]
The above composition is dispersed in a flask, and heating is started while performing nitrogen substitution. When the liquid temperature reached 65 ° C., a solution prepared by dissolving 5.85 parts of potassium persulfate in 300 parts of ion exchange water was added thereto. While maintaining the liquid temperature at 65 ° C., the monomer mixture was added and stirred, the liquid temperature was raised to 75 ° C. and emulsion polymerization was continued for 5 hours. After the liquid temperature was adjusted to 40 ° C., the mixture was filtered with a dispersion B Got. Thus, the particle diameter in the obtained dispersion was 0.16 μm in average particle diameter, 63 ° C. in glass transition point of solid content, and 600,000 in weight average molecular weight (Mw). The hydrocarbon wax was contained in the polymer by 6%, and as a result of observing a thin piece of this solid content with a transmission electron microscope, it was confirmed that the wax particles were encapsulated. The THF-insoluble content of the polymer was 7%.
[0056]

The above was mixed and dispersed using a sand grinder mill to obtain a carbon black dispersion C.
[0057]
300 parts of dispersion A, 150 parts of dispersion B and 25 parts of dispersion C were charged into a 1 liter separable flask equipped with a stirrer, a condenser and a thermometer, and stirred. To this mixed solution, 180 parts of a 10% aqueous sodium chloride solution was added dropwise as a flocculant, and the mixture was heated to 54 ° C. while stirring the inside of the flask in a heating oil bath. After maintaining at 48 ° C. for 1 hour, it was confirmed by observation with an optical microscope that associated particles having a diameter of about 5 μm were formed.
[0058]
In the subsequent fusing process, after adding 3 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC), the stainless steel flask was sealed and stirring was continued using a magnetic seal. The mixture was heated to 100 ° C. and held for 3 hours. Then, after cooling, the reaction product was filtered, washed thoroughly with ion exchange water, and then dried to obtain toner particles 1.
[0059]
The BET specific surface area is 200 m with respect to 100 parts of the toner particles.²/ G of 0.7 part of hydrophobic silica and 0.7 part of hydrophobic titanium oxide having a primary particle diameter of 80 nm are added and dry mixed. The weight average particle diameter is 5.0 μm, SF2 is 144, and SF2 varies. Toner 1 having a coefficient of 6.3 was used.
[0060]
The toner particles 1 and toner 1 have a peak molecular weight of 11,000, a THF-insoluble content of 3%, and a Mw of 210,000 by gel permeation chromatography (hereinafter referred to as GPC). 5 parts of the toner 1 was mixed with 100 parts of the carrier of Production Example 1 of carrier particles to obtain a two-component developer 1. 100 parts of the toner was mixed with 25 parts of the carrier of Production Example 1 for carrier particles to obtain a replenishing developer. In the present invention, the particle size of the particles in the dispersion is a number average particle size measured using a particle size measurement device (LA-700, manufactured by Horiba, Ltd.).
[0061]
In the present invention, the molecular weight distribution by GPC using the polymer THF as a solvent is measured under the following conditions.
<Measurement of molecular weight distribution by GPC>
The column is stabilized in a heat chamber at 40 ° C., and THF as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 ml per minute, and about 100 μl of the THF sample solution is injected and measured. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count value. As a standard polystyrene sample for preparing a calibration curve, for example, a molecular weight of 10 manufactured by Tosoh Corporation or Showa Denko KK is 10²-10⁷It is appropriate to use a standard polystyrene sample of about 10 points. An RI (refractive index) detector is used as the detector.
[0062]
As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, a combination of shodex GPC KF-801, 802, 803, 804, 805, 806, 807, 800P manufactured by Showa Denko KK Examples include TSKgel G1000H (HXL), G2000H (HXL), G3000H (HXL), G4000H (HXL), G5000H (HXL), G6000H (HXL), G7000H (HXL), and TSKgurd column.
[0063]
The sample is prepared as follows. Place the sample in THF and let stand for several hours, then shake well and mix well with THF (until the sample is no longer united) and let stand for more than 12 hours. At that time, the standing time in THF should be 24 hours or more. Thereafter, a sample processed filter (pore size 0.2 to 0.5 μm, for example, Mysori Disc H-25-2 (manufactured by Tosoh Corporation) can be used) is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.
[0064]
In the present invention, the THF-insoluble content of the resin component in the toner and the THF-insoluble content of the raw material binder resin are measured as follows.
<Measurement of THF-insoluble matter>
Binder resin and toner 0.5-1.0g are weighed (W1g), cylindrical filter paper (for example, No. 86R manufactured by Toyo Roshi Kaisha Co., Ltd.) is put into a Soxhlet extractor, and extracted for 10 hours using 200ml of THF as a solvent. After evaporating the soluble component solution extracted with the solvent, the solution is vacuum dried at 100 ° C. for several hours, and the amount of the THF soluble resin component is weighed (W2 g). The weight other than the resin component in the toner is determined (W3g). The THF-insoluble content can be obtained from the following formula.

[0065]
In the present invention, the melting point of the wax is defined as the melting point of the wax at the peak top temperature of the endothermic peak of the wax measured by DSC. In the present invention, the DSC measurement using a differential scanning calorimeter for wax or toner is preferably performed using a differential scanning calorimeter with high accuracy of internal heat input compensation. For example, DSC-7 manufactured by Perkin Elmer can be used. The measurement method is performed according to ASTM D3418-82. The DSC curve used in the present invention is a DSC curve measured when the temperature is raised after raising the temperature once, taking the previous history, then lowering the temperature in the range of 10 ° C./min, and the temperature of 0 to 200 ° C. Is used. The glass transition point Tg is measured with, for example, a highly accurate internal heating input compensation type differential scanning calorimeter such as DSC-7 manufactured by PerkinElmer. The measurement method is performed according to ASTM D3418-82.
[0066]
<Production Example 2 for Replenishment Developer and Two-Component Developer>
A two-component developer 2 and a replenishment developer 2 were prepared in the same manner as in Production Example 1 of the toner, the replenishment developer, and the two-component developer, except that the carrier of Production Example 2 of the carrier was used as the carrier. .
[0067]
<Production Example 3 of Toner, Replenishment Developer, and Two-Component Developer>
・ Styrene-n-butyl acrylate copolymer resin
(Copolymerization ratio 80:20, Mw 14,000) 50 parts
・ Styrene-n-butyl acrylate copolymer resin
(Copolymerization ratio 80:20, Mw 300,000) 50 parts
・ 7 parts of carbon black
-2 parts low molecular weight polypropylene wax with a melting point of 130 ° C
・ 2 parts of hydrocarbon wax with melting point 75 ℃
・ Azo iron compound 2 parts
[0068]
After the above mixture is dry-mixed, it is melt-kneaded, pulverized and classified to toner particles2Got. The BET specific surface area is 200 m with respect to 100 parts of the toner particles 2.²0.7 parts of hydrophobic silica having a weight average particle diameter of 0.7 nm and a dry titanium oxide having a number average primary particle diameter of 80 nm are added and dry-mixed, and the weight average particle diameter is 6.2 μm, SF2 is 151, SF2 A toner 2 having a coefficient of variation of 13.9 was obtained. 5 parts of toner 2 is mixed with 100 parts of carrier of carrier production example 2 to form two-component developer 3, and 25 parts of carrier of carrier production example 2 are mixed with 100 parts of toner 2 for replenishment development. Agent 3 was obtained.
[0069]
<Production Example 4 for Replenishment Developer and Two-Component Developer>
A two-component developer 4 and a replenishment developer 4 were prepared in the same manner as in Production Example 3 of the toner, the replenishment developer, and the two-component developer, except that the carrier of Production Example 3 of the carrier was used. .
[0070]
<Production Example 5 of Toner, Replenishment Developer, and Two-Component Developer>
Toner particles 2 obtained in Production Example 3 of toner, replenishment developer, and two-component developer were heat spheroidized to obtain toner particles 3. Thereafter, a replenishment developer 5 and a two-component developer 5 were obtained in the same manner as in Production Example 3 of toner, replenishment developer, and two-component developer. The weight average particle diameter is 6.4 μm, SF2 is 115, and the variation coefficient of SF2 is 3.0.
[0071]
Example 1
The following evaluation was performed using the image forming apparatus shown in FIG. As an image carrier used, an aluminum cylinder subjected to φ30 anodizing treatment, a 0.5 μm-thick undercoat layer containing polyamide resin, a 0.1 μm-thick charge generation layer comprising a polyvinyl butyral resin and a phthalocyanine pigment And a 20 μm-thick charge transporting layer comprising a polycarbonate resin and a charge transporting material, and the surface layer is a film in which an acrylic polyfunctional monomer in which conductive fine particles and PTFE particles are dispersed is cured with ultraviolet rays to form a crosslinked resin. A photosensitive drum obtained by forming a surface layer of 3 μm was used. Two-component developer 1 was used as the two-component developer, and replenishment developer 1 was used as the replenishment developer.
[0072]
In this embodiment, the charger 101 is a scorotron charger, and is adjusted so as to obtain a dark portion potential of −600 V at the position of the developing means 104. As the exposure means 103, a semiconductor laser is used, and the bright portion exposure potential is set to -120V. In the developing means 104, the gap between the photosensitive member and the non-magnetic sleeve containing the magnet is set to 500 μm, and a two-component developer is supported. A rectangular wave AC voltage of 3 kHz, Vpp 2000 V is applied to the non-magnetic sleeve, The DC component is -450V.
[0073]
The developing means 104 is charged with 210 g of a two-component developer, and the toner density is controlled by a toner density detecting means (not shown). In this embodiment, when 125 g of replenishment developer is replenished, 25 g of carrier is replenished in the developing machine, and corresponding to replenishment of 125 g of replenishment developer, about 26 g of the two-component developer in the developing means. Will be discharged and replaced. As a means for adjusting the discharge amount, a window is provided on the side surface of the developing unit 104 corresponding to the powder surface of the two-component developer in the developing unit 104, and the replenishment developer is replenished during image formation. Open when not in use and discharge. The discharged developer is stored in the discharged developer storage unit through the discharge path 116.
[0074]
Under these conditions, a character image with a printing ratio of 10% is formed, and continuous printing is performed with A4 landscape feed. A transfer charger 105 (in this embodiment, a conductive roller having a diameter of 16 is used as a roller transfer method) is transferred onto transfer paper, and the developer remaining on the transfer is cleaned by a cleaning means 106 having a blade. Collected. The collected transfer residual developer is supplied to the developing unit 104 together with the supply developer. Further, a blackish image of about 5 mm is formed every 100 prints, and cleaning is performed without transferring.
[0075]
Under the above condition settings, 100,000 images were printed in an environment of 23 ° C. and 60% relative humidity. Evaluation is as follows.
(1) Image density
Ordinary paper for ordinary copying machines (75 g / m²) Is measured using a Macbeth reflection densitometer (manufactured by Macbeth).
(2) Cover
Measured using a reflection densitometer (REFLECTOMETER ODEL TC-6DS manufactured by TOKYO DENSHOKU CO., LTD) (when the average reflection density on the white background after printing is Ds and the average reflection density on the paper before printing is Dr) Ds-Dr was used as the fogging amount). (A fogging amount of 2% or less is a good image with substantially no fogging, and if it exceeds 5%, the fogging is conspicuous.)
[0076]
(3) Fine line reproducibility
About 2 mm square “Den” characters were magnified 30 times and evaluated according to the following evaluation criteria.
A: The character line is faint.
B: The character line is slightly thinned.
C: The character line is sharp.
D: The character line is slightly overweight.
E: Characters are crushed.
(4) Image carrier scratch-like scratch
(5) Image failure due to image carrier wear
The above results are shown in Table 1 below.
[0077]
Example 2
Evaluation was performed in the same manner as in Example 1 except that the two-component developer 2 was used as the two-component developer and the supply developer 2 was used as the supply developer. The result was satisfactory, except that on the 100,000th sheet, the photoconductor was slightly scratched. The above results are shown in Table 1 below.
[0078]
Example 3
Evaluation was performed in the same manner as in Example 1 except that the two-component developer 3 was used as the two-component developer and the supply developer 3 was used as the supply developer. On the 100,000th sheet, there was no problem except that a slight scratch-like scratch was generated on the photoreceptor and the fogging slightly increased. The above results are shown in Table 1 below.
[0079]
Example 4
As the two-component developer, the two-component developer 3 was used, and as the replenishment developer, the replenishment developer 3 was used. Except that a blackish image of about 5 mm was not formed every 100 prints. Evaluation was conducted in the same manner as in Example 1. On the 50,000th sheet, a slight scratch-like scratch was formed on the photoconductor, and on the 100,000th sheet, the fog slightly increased, resulting in a scratch-like scratch, but there was no problem with the wear of the photoconductor. Met. The above results are shown in Table 1 below.
[0080]
Example 5
As the two-component developer, the two-component developer 5 was used, and as the replenishment developer, the replenishment developer 5 was used. Except that a blackish image of about 5 mm was not formed every 100 prints. Evaluation was conducted in the same manner as in Example 1. The results are shown in Table 1 below.
[0081]
referenceExample1
  As the two-component developer, the two-component developer 4 was used, and as the replenishment developer, the replenishment developer 4 was used. Except that a blackish image of about 5 mm was not formed every 100 prints. Evaluation was conducted in the same manner as in Example 1. On the 80,000th sheet, an image defect due to photoconductor wear appeared, so the evaluation was terminated. The above results are shown in Table 1 below.
[0082]
Comparative Example 1
As the two-component developer, the two-component developer 4 was used, and as the replenishment developer, the replenishment developer 4 was used. For every 100 sheets printed, a blackish image of about 5 mm was not formed. Except that the surface layer having a film thickness of 3 μm was not formed by curing an acrylic polyfunctional monomer in which conductive fine particles and PTFE particles were dispersed with ultraviolet rays to form a cross-linked resin, and the charge transport layer was 23 μm. 1 was evaluated in the same manner. Since an image defect due to photoconductor wear appeared on the 40,000th sheet, the evaluation was terminated. The above results are shown in Table 1 below.
[0083]

[0084]
【The invention's effect】
According to the configuration of the present invention, even when a long-life photoconductor is used and fine toner is used, a high-definition image can be achieved over a long period of time without requiring maintenance work, and collected by cleaning. Even when the transfer residual developer is reused, the development characteristics do not deteriorate, the adhesion of the developer component to the photoreceptor is prevented, and a high-definition image can be obtained over a long period of time.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an image forming method of the present invention.
[Explanation of symbols]
101: Charger
102: Image carrier (photosensitive member)
103: Exposure means
104: Development means
105: Transfer charger
106: Cleaning means
107: Pre-charging exposure means
108: Transfer material conveyance belt
109: Fixing device
110: Transfer material conveyance guide
111: Registration roller
112: Developer transport path
113: Developer storage means
114: Developer supply bottle
115: Supply route
116: Discharge path
117: Discharged developer storage means

Claims (6)

A latent image is formed on the image bearing member, the latent image is developed by a developing unit using a two-component developer containing toner and carrier, and a replenishment developer is supplied to the developing unit as necessary. In the image forming method, the developer is discharged from the means as needed, the developed image is transferred, and the residual developer remaining on the image carrier is cleaned.
The replenishment developer contains a carrier,
The carrier has a volume 50% diameter (D50: unit μm), a volume 5% diameter (D5: unit μm), and a volume 16% diameter (D16: unit μm) in the following relationship:
30 μm ≦ D50 ≦ 40 μm
0.50 ≦ D5 / D50
0.65 ≦ D16 / D50
The image carrier contains a resin whose surface has a crosslinked structure ,
Image forming method characterized by the developer of the upper Symbol cleaned collected transferred residual for reuse is supplied to the developing unit. The image forming method according to claim 1, further comprising: developing the toner included in the developing unit on an image carrier, and cleaning the toner without transferring it. The replenishment developer contains a toner, and the toner contains a binder resin, a colorant, and a wax, and a polymer obtained by polymerizing a monomer is present on the surface of the wax in an aqueous medium. plurality agglomerated particles, an image forming method according to claim 1 or 2 containing toner particles comprising fused. The replenishment developer contains a toner, an image forming method according to any one of claims 1 to 3 The number average primary particle diameter to the surface of toner particles is present inorganic particles is 50 to 200 nm. The replenishment developer contains a toner, the weight average particle diameter of the toner, the image forming method according to any one of claims 1 to 4 is 3.0～6.0Myuemu. The replenishment developer contains a toner, SF2 of the toner, a 120 to 170, the variation coefficient of the SF2 is, any one of claims 1 to 5 is 4.0 to 8.0 The image forming method described in 1.

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