JP2004271584A - Method for manufacturing toner, toner, and its concentrated liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing toner which emits no offensive odor in heat fixation, gives an odorless print having image fade resistance comparable to that of offset printing, and is excellent in manufacture stability, and to provide a toner and its concentrated liquid. <P>SOLUTION: The method for manufacturing the toner includes a step in which a resin particle dispersion is formed by dispersing resin particles in an aqueous medium and the resin particles in the resin particle dispersion are agglomerated, wherein a step of preparing a concentrated liquid by concentrating the resin particle dispersion is included. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

ここで、相当円とは、トナー粒子投影像と同じ面積を有する円のことであり、円相当径とは、該相当円の直径のことである。
【００５４】
なお、上記円形度の測定方法としては、ＦＰＩＡ−２０００（シスメック社製）により測定することができる。この時、円相当径は下式で定義される。
【００５５】
円相当径＝２×（粒子の投影面積／π）^１／２
又、本発明のトナーの形状は、円相当径の平均値が、２．６〜７．４μｍにあり、円相当径に対する円形度の傾きが−０．０５０〜−０．０１０であることを特徴とする。より好ましくは、円相当径の平均値が３．４〜６．６μｍにあり、円相当径に対する円形度の傾きが−０．０４０〜−０．０２０であるのがよい。
【００５６】
本発明者等は、質量が大きめで円形度が低い粒子に、転写材にくさびのように転写を行わせ、そのすきまを埋めるように小径で円形度の高い粒子を転写し、最密充填の状態になるように調整して画像を形成した。この画像を定着すると、トナー粒子同士がシンタリングして良好な定着強度がえられることが判った。
【００５７】
但し、粒子の円形度と円相当径は離散的に分布するのでは、効果が不十分であった。
【００５８】
そこで、本発明者等は、円相当径に対する円形度の傾きとして、連続的にそれらを変化させる概念を初めて導き出し、厚紙でも良好な定着強度を得ることが出来ることを見出した。
【００５９】
円相当径の傾きの測定は、フロー式粒子像分析装置ＦＰＩＡ−２０００でトナー粒子の円相当径を測定し、それに対応する円形度との関係を、横軸：円相当径（μｍ）−縦軸：円形度として描き、その一次の相関（ｙ＝αｘ＋ｂ）をみれば、αが円相当径の傾きとなる。
【００６０】
この時、帯電の均一性、ハーフトーンの均一性を高める観点からＲ^２（Ｒの２乗）は０．３５〜０．９５が好ましい。ここにおいてＲは下記一般式（１）で表される。
【００６１】
一般式（１）
Ｒ＝Ａ／Ｂ
式中、Ａ、Ｂは各々下記式を表す。
【００６２】
Ａ＝ｎΣＸＹ−（ΣＸΣＹ）
Ｂ＝（ｎΣＸ^２−（ΣＸ）^２）×（（ｎΣＹ^２）−（ΣＹ）^２）
Ｘは円相当径（μｍ）、Ｙは円形度を表す。
【００６３】
また、円相当径の傾きを有するトナーを造るには、小粒径の球形トナー粒子にやや粒径の大きい異形のトナー粒子を混合しても良い。或いは、後述する樹脂粒子を会合してトナー粒子を造る方法においては、会合工程で凝集剤を添加した後、撹拌羽根形状を適宜選択し、撹拌強度を制御し、大きめの粒子に剪断力がかかり易い条件として、濾過、乾燥工程に移行する方法でもよい。好ましくは、トナー製造装置と前述のフロー式粒子像分析装置をインライン接続し、傾きαをモニタリングしつつ、適宜条件を調整しながら製造する。
【００６４】
好ましくは凝集剤を投入した後、例えば凝集剤の再添加や界面活性剤の追加により、トナー粒子をさらに０．２〜１．０μｍ成長させると、本発明の範囲内に入るよう制御することが出来る。
【００６５】
次に、本発明で用いられる画像形成方法、画像形成装置について説明する。
図２は、本発明のトナーを用いる画像形成方法の一例を示す画像形成装置の断面構成図である。
【００６６】
図２において、画像形成装置１０１は、自動原稿搬送装置（通称ＡＤＦ）Ａと、自動原稿搬送装置により搬送される原稿の画像を読み取るための原稿画像読取部Ｂと、読み取った原稿画像を処理する画像制御基板Ｃと、画像処理後のデータに従って像担持体としての感光体ドラム３４上に書き込みを行う書き込みユニット１１２を含む書き込み部Ｄと、感光体ドラム３４及びその周囲に帯電器３５、磁気ブラシ型現像装置からなる現像器３６、転写器３７、分離器３９、クリーニング器４１等の画像形成手段を含む画像形成部Ｅと、記録紙Ｐを収納する給紙トレイ１２２、１２４のための収納部Ｆを有している。
【００６７】
自動原稿搬送装置Ａは、原稿載置台１２６と、ローラＲ１を含むローラ群および原稿の移動通路を適宜切り替えるための切換手段等（参照記号なし）を含む原稿搬送処理部１２８とを主要素とする。
【００６８】
原稿画像読取部Ｂは、プラテンガラスＧの下にあり、光路長を保って往復移動できる２つのミラーユニット１３０、１３１、固定の結像レンズ（以下、単にレンズという）１３３、ライン状の撮像素子（以下、ＣＣＤという）１３５等からなり、書き込み部Ｄは、レーザ光源３１、ポリゴンミラー（偏光器）３２等からなる。
【００６９】
転写材としての記録紙Ｐの移動方向からみて、転写器３７の手前側に示すＲ１０はレジストローラであり、分離器３９の下流側にＨで示してあるのは定着手段である。
【００７０】
定着手段Ｈは、実施の形態においては、加熱源を内蔵するローラと、当該ローラに圧接しながら回転する圧接ローラとで構成してある。
【００７１】
また、Ｚは定着手段Ｈのためのクリーニング手段で、巻き取り可能に設けたクリーニングウェブを主要素とする。
【００７２】
原稿載置台１２６上に載置される原稿（図示せず）の１枚が原稿搬送処理部１２８によって搬送され、ローラＲ１の下を通過中に、露光手段Ｌによる露光が行われる。
【００７３】
原稿からの反射光は、固定位置にあるミラーユニット１３０、１３１およびレンズ１３３を経てＣＣＤ１３５上に結像され、読み取られる。
【００７４】
原稿画像読取部Ｂで読み取られた画像情報は、画像処理手段により処理され、符号化されて画像制御基板Ｃ上に設けてあるメモリーに格納される。
【００７５】
また、画像データは画像形成に応じて呼び出され、当該画像データに従って、書き込み部Ｄにおけるレーザ光源３１が駆動され、感光体ドラム３４上に露光が行われる。
【００７６】
近年、感光体上に静電潜像を形成し、この潜像を現像して可視画像を得る電子写真等の分野において、画質の改善、変換、編集等が容易で高品質の画像形成が可能なデジタル方式を採用した画像形成方法の研究開発が盛んになされている。
【００７７】
この画像形成方法及び装置に採用されるコンピュータまたは複写原稿からのデジタル画像信号により光変調する走査光学系として、レーザ光学系に音響光学変調器を介在させ、当該音響光学変調器により光変調する装置、半導体レーザを用い、レーザ強度を直接変調する装置があり、これらの走査光学系から一様に帯電した感光体上にスポット露光してドット状の画像を形成する。
【００７８】
前述の走査光学系から照射されるビームは、裾が左右に広がった正規分布状に近似した丸状や楕円状の輝度分布となり、例えばレーザビームの場合、通常、感光体上で主走査方向あるいは副走査方向の一方あるいは両者が２０〜１００μｍという極めて狭い丸状あるいは楕円状である。
【００７９】
本発明に係るトナーは、トナー像が形成された画像形成支持体を、定着装置を構成する加熱ローラーと加圧ローラーとの間に通過させて定着する工程を含む画像形成方法に好適に使用される。
【００８０】
【実施例】
以下実施例により本発明をさらに説明するが、本発明はこれに限定されるものではない。以下の記載において「部」は質量部、「％」は質量％を示す。
【００８１】
《実施例１》
〈濃縮液１の調製〉
（ラテックス（１ＨＭＬ）の調製）
（１）核粒子の調製（第一段重合）
攪拌装置、温度センサー、冷却管、窒素導入装置を取り付けた５０００ｍｌのセパラブルフラスコにアニオン系分散安定剤
式（１０１） Ｃ_１０Ｈ_２１（ＯＣＨ_２ＣＨ_２）_２ＯＳＯ_３Ｎａ
７．０８ｇをイオン交換水３０１０ｇに溶解させた分散安定剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの攪拌速度で攪拌しながら、フラスコ内の温度を８０℃に昇温させた。
【００８２】
この分散安定剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）９．２ｇをイオン交換水２００ｇに溶解させた開始剤溶液を添加し、温度を７５℃とした後、スチレン７０．１ｇ、ｎ−ブチルアクリレート１９．９ｇ、メタクリル酸１０．９ｇからなる単量体混合液を１時間かけて滴下し、この系を７５℃にて２時間にわたり加熱、攪拌することにより重合（第一段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（１Ｈ）」とする。
（２）中間層の形成（第二段重合）
攪拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．２ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル５．６ｇからなる単量体混合液に離型剤として、下記式で表される化合物（以下、「例示化合物（１９）」と云う）９８．０ｇを添加し、９０℃に加温し溶解させて単量体溶液を調製した。
【００８３】
例示化合物（１９）
ＣＨ_３（ＣＨ_２）_２０ＣＯＯＣＨ_２Ｃ（ＣＨ_２ＯＣＯ（ＣＨ_２）_２０ＣＨ_３）_３
一方、アニオン系分散安定剤（上記式（１０１））１．６ｇをイオン交換水２７００ｍｌに溶解させた分散安定剤溶液を９８℃に加熱し、この界面活性剤溶液に、核粒子の分散液である前記「ラテックス（１Ｈ）」を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック株式会社製）により、前記例示化合物（１９）の単量体溶液を８時間混合分散させて２８４ｎｍの分散粒子径を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【００８４】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液とイオン交換水７５０ｍｌとを添加し、この系を９８℃にて１２時間にわたり加熱攪拌することにより重合（第二段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを「ラテックス（１ＨＭ）」とする。
（３）外層の形成（第三段重合）
上記の様にして得られた「ラテックス（１ＨＭ）」に、重合開始剤（ＫＰＳ）７．４ｇをイオン交換水２００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン３００ｇ、ｎ−ブチルアクリレート９５ｇ、メタクリル酸１５．３ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル１０．４ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱攪拌することにより重合（第三段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層に例示化合物（１９）が含有されている複合樹脂粒子の分散液）（１ＨＭＬ）を得た。このラテックス（１ＨＭＬ）を「樹脂粒子分散液１」とする。
【００８５】
この「樹脂粒子分散液１」を構成する複合樹脂粒子は、１３８，０００、８０，０００および１３，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の質量平均粒径は１２２ｎｍであった。
【００８６】
次に、「樹脂粒子分散液１」を図１に示す遠心分離型（ディスク型）濃縮装置（沈降板間隔０．５ｍｍ、装置設置面積に対する全沈降板の面積が５００倍）を用い、回転数３０００ｒｐｍで作動させて、固形分濃度が６０質量％になるまで水分を除去して「濃縮液１」を調製し、移送容器（タンク）に一次保管した。
【００８７】
〈トナー粒子１の調製〉
移送容器中の「濃縮液１」をポンプでインぺラーの備わった攪拌容器に移送し、水で希釈して固形分濃度が１５質量％の「樹脂粒子再分散液１」を調製した。
【００８８】
「樹脂粒子再分散液１」 １００部
カーボンブラック １２部
帯電制御剤「スピロンブラックＴＲＨ」（保土ケ谷化学株式会社製） １部
イオン交換水 ７００部
ドデシルベンゼンスルホン酸ナトリウム １部
上記化合物を撹拌容器のインペラーで撹拌し均一に混合した。
【００８９】
次に、塩化アルミニウム１０部をイオン交換水９０部に溶解した「水溶液１」を、低速でインペラーを攪拌しながら徐々に滴下することにより、凝集粒子を形成させ、その後液温を７０℃に保ち、凝集が合一融解したのを一部サンプリングして走査型電子顕微鏡により確認した。
【００９０】
その後９５℃で８時間攪拌し、凝集粒子の円形度が０．９６３になったところで、水を加え４０℃まで冷却し、攪拌を停止した。
【００９１】
その後、水洗と濾過を繰り返し、得られたケーキを減圧乾燥して黒色の「トナー粒子１」を調製した。なお、円形度は乾燥によりさらに増した。
【００９２】
《実施例２》
〈濃縮液２の調製〉
冷却管、撹拌機および窒素導入管の付いた反応容器中に、ビスフェノールＡエチレンオキサイド２モル付加物３４３０部、イソフタル酸１６６０部およびジブチルチンオキサイド２０部を入れ、常圧で２３０℃で８時間反応し、さらに１０〜１５ｍｍＨｇ（１．３３〜１．９９Ｐａ）の減圧で５時間反応した後、１１０℃まで冷却し、トルエン中にてイソホロンジイソシアネート１７部を入れて１１０℃で５時間反応を行い、次いで脱溶剤し、質量平均分子量７２，０００、遊離イソシアネート含量０．７％の「ウレタン変性ポリエステル（２）」を得た。上記と同様にビスフェノールＡエチレンオキサイド２モル付加物５７００部、テレフタル酸２１７０部を常圧下、２３０℃で６時間重縮合し、数平均分子量２，４００、水酸基価５１、酸価５の変性されていない「ポリエステル（２）」を得た。「ウレタン変性ポリエステル（２）」２０００部と「ポリエステル（２）」８０００部を酢酸エチル２０，０００部に溶解、混合し、固形分濃度１５質量％の「樹脂溶液２」を得た。該「樹脂溶液２」の一部を減圧乾燥し、樹脂分を単離した。該樹脂分のＴｇは５５℃であった。
【００９３】
ビーカー内に、水５００部、ノニルフェノールエチレンオキサイド１４モル付加物「ノニポール２００」（三洋化成工業製）４０部を入れ均一に溶解した。ＴＫ式ホモミキサーで１８，０００ｒｐｍに撹拌しながら、「樹脂溶液２」を投入し１５分間撹拌した。ついでこの混合液を撹拌棒および温度計付の反応容器に移し、昇温して酢酸エチルを留去し、さらに９８℃まで昇温して５時間反応させて、「ウレタン変性ポリエステル（２）」の水伸長反応物と「ポリエステル（２）」の混合物からなる固形分濃度１５質量％の「樹脂粒子分散液２」を得た。「樹脂粒子分散液２」をＬＡ−９２０で測定した体積平均粒径は、０．２１μｍであった。また、「樹脂粒子分散液２」の一部を遠心分離し、更に水を加えて遠心分離する工程を２回繰り返した後、乾燥して樹脂分を単離した。該樹脂分のＴｇは６４℃であった。
【００９４】
次に、「樹脂粒子分散液２」を図１に示す遠心分離型（ディスク型）濃縮装置（沈降板間隔０．５ｍｍ、装置設置面積に対する全沈降板の面積が５００倍）を用い、回転数３０００ｒｐｍで作動させて、固形分濃度が６０質量％になるまで水を除去して「濃縮液２」を調製し、移送容器（タンク）に一次保管した。
【００９５】
〈トナー粒子２の調製〉
移送容器中の「濃縮液２」をポンプでインぺラーの備わった攪拌容器に移送し、水で希釈して固形分濃度が１５質量％の「樹脂粒子再分散液２」を調製した。
【００９６】
「樹脂粒子再分散液２」 １００部
カーボンブラック １２部
帯電制御剤「スピロンブラックＴＲＨ」（保土ケ谷化学株式会社製） １部
カルナウバワックス １０部
イオン交換水 ７００部
ドデシルベンゼンスルホン酸ナトリウム １部
上記化合物を撹拌容器のインペラーで撹拌し均一に混合した。
【００９７】
次に、塩化アルミニウム１０部をイオン交換水９０部に溶解した「水溶液２」を、低速でインペラーを攪拌しながら徐々に滴下することにより、凝集粒子を形成させ、その後液温を７０℃に保ち、凝集が合一融解したのを一部サンプリングして走査型電子顕微鏡により確認した。
【００９８】
その後９５℃で８時間攪拌し、凝集粒子の円形度が０．９６３になったところで、水を加え４０℃まで冷却し、攪拌を停止した。
【００９９】
その後、水洗と濾過を繰り返し、得られたケーキを減圧乾燥して黒色の「トナー粒子２」を得た。なお、円形度は乾燥によりさらに増した。
【０１００】
《実施例３》
〈濃縮液３の調製〉
冷却管、撹拌機および窒素導入管の付いた反応容器中に、ビスフェノールＡエチレンオキサイド２モル付加物３４３部、イソフタル酸１６６部およびジブチルチンオキサイド２部を入れ、常圧で２３０℃で８時間反応し、さらに１０〜１５ｍｍＨｇ（１．３３〜１．９９Ｐａ）の減圧で５時間反応した後、１１０℃まで冷却し、トルエン中にてイソホロンジイソシアネート１７部を入れて１１０℃で５時間反応を行い、次いで脱溶剤し、質量平均分子量７２，０００、遊離イソシアネート含量０．７％の「ウレタン変性ポリエステル（３）」を得た。上記と同様にビスフェノールＡエチレンオキサイド２モル付加物５７０部、テレフタル酸２１７部を常圧下、２３０℃で６時間重縮合し、数平均分子量２，４００、水酸基価５１、酸価５の変性されていない「ポリエステル（３）」を得た。「ウレタン変性ポリエステル（３）」２００部と「ポリエステル（３）」８００部を酢酸エチル２，０００部に溶解、混合し、固形分濃度１５質量％の「樹脂溶液３」を得た。該「樹脂溶液３」の一部を減圧乾燥し、樹脂分を単離した。該樹脂分のＴｇは５５℃であった。
【０１０１】
「樹脂溶液３」 １００部
カーボンブラック １２部
帯電制御剤「スピロンブラックＴＲＨ」（保土ケ谷化学株式会社製） １部
カルナウバワックス １０部
上記材料をトルエン２００部中でジルコニアビーズの充填されたボールミルを転動させることによって溶解分散し、分散相となる「油相３」を調製した。
【０１０２】
別途、
イオン交換水 ７００部
ドデシルベンゼンスルホン酸ナトリウム １部
を攪拌分散し連続相となる「水相３」を調製した。この「水相３」中に「ホモミキサー」（特殊機化工業株式会社製）で攪拌しながら「油相３」を投入し、攪拌回転数を調整することにより体積平均粒径約１μｍの「油滴３」を調製した。その後、５０℃で減圧溜去してトルエンを除去し、固形分濃度１５質量％の黒色の「樹脂粒子分散液３」を得た。
【０１０３】
次に、「樹脂粒子分散液３」を図１に示す遠心分離型（ディスク型）濃縮装置（沈降板間隔０．５ｍｍ、装置設置面積に対する全沈降板の面積が５００倍）を用い、回転数３０００ｒｐｍで作動させて、固形分濃度が６０質量％になるまで水を除去して「濃縮液３」を調製し、移送容器（タンク）に一次保管した。
【０１０４】
〈トナー粒子３の調製〉
移送容器中の「濃縮液３」をポンプでインぺラーの備わった攪拌容器一定量移し、水で希釈して固形分濃度が１５質量％の「樹脂粒子再分散液３」を調製した。
【０１０５】
次に、塩化アルミニウム１０部をイオン交換水９０部に溶解した「水溶液３」を、低速でインペラーを攪拌しながら徐々に滴下することにより、凝集粒子を形成させ、その後液温を７０℃に保ち、凝集が合一融解したのを一部サンプリングして走査型電子顕微鏡により確認した。
【０１０６】
その後、９５℃で８時間攪拌し、凝集粒子の円形度が０．９６３になったところで、４０℃まで冷却し、攪拌を停止した。
【０１０７】
その後、水洗と濾過を繰り返し、得られたケーキを減圧乾燥して黒色の「トナー粒子３」を作製した。なお、円形度は乾燥によりさらに増した。
【０１０８】
《実施例４》
実施例３の「濃縮液３」の固形分濃度６０質量％を５０質量％に、「樹脂粒子再分散液３」の固形分濃度を１５質量％を２０質量％に変更した以外は、実施例３と同様にして「トナー粒子４」を調製した。
【０１０９】
《実施例５》
実施例３の「濃縮液３」の固形分濃度６０質量％はそのままで、「樹脂粒子再分散液３」の固形分濃度を１５質量％を２０質量％に変更した以外は、実施例３と同様にして「トナー粒子５」を調製した。
【０１１０】
《実施例６》
実施例３の「濃縮液３」の固形分濃度６０質量％を７５質量％に、「樹脂粒子再分散液３」の固形分濃度を１５質量％を２０質量％に変更した以外は、実施例３と同様にして「トナー粒子６」を調製した。
【０１１１】
《実施例７》
実施例３の「濃縮液３」の固形分濃度６０質量％を４０質量％に、水による希釈を行わなかった以外は、実施例３と同様にして「トナー粒子７」を調製した。
【０１１２】
《実施例８》
実施例３の「濃縮液３」の固形分濃度６０質量％を８０質量％に、「樹脂粒子再分散液３」の固形分濃度を１５質量％を３０質量％に変更した以外は、実施例３と同様にして「トナー粒子８」を調製した。
【０１１３】
《実施例９》
実施例３の「樹脂粒子分散液３」をフラッシュドライヤーで水分量を０．５質量％に乾燥した後、水で希釈し固形分濃度１５質量％の「樹脂粒子再分散液９」を調製した以外は、実施例３と同様にして「トナー粒子９」を調製した。
【０１１４】
《実施例１０》
実施例３の「樹脂粒子分散液３」の濃縮を行わなかった以外は、実施例３と同様にして「着色粒子１０」を調製した。
【０１１５】
表１に、樹脂粒子分散液の固形分濃度、濃縮液の固形分濃度、樹脂粒子再分散液の固形分濃度、円形度の平均値、円相当径の平均値、円相当径に対する円形度の傾きを示す。
【０１１６】
【表１】

【０１１７】
〈トナーの作製〉
実施例で調製した各々の「トナー粒子１〜１０」１００部と疎水性シリカＲ９７２（一次粒子径１６ｎｍ：日本アエロジル株式会社製）０．５部をヘンシェルミキサーにより混合し、目開き５０μｍの篩で粗大粒子や凝集物を取り除き、「トナー１〜１０」を作製した。
【０１１８】
〈現像剤の調製〉
上記のようにして製造した「トナー１〜１０」の各々と６０μｍのマンガンフェライトにシリコーンコートした「キャリア」とをヘンシェルミキサーを用いて混合し、トナー濃度が６質量％の「現像剤１〜１０」を調製した。
【０１１９】
《評価》
市販の電子写真式デジタルマルチファンクション複写機「Ｓｉｔｉｏｓ７０７５ＨＶ」（コニカ株式会社製）に「現像剤１〜１０」を順次セットし、「トナー１〜１０」を用いてプリントを行い、下記の項目について評価を行った。
【０１２０】
〈プリント時の臭気〉
軽印刷業に従事している１０人にモニターになってもらい、Ａ４サイズで黒化面積率１２％の画像を、連続５０００枚プリントしたときに定着部から発生する臭気の程度を評価してもらった。
【０１２１】
評価基準
◎：１０人中８人以上が、臭気が気にならないと評価したので実用上問題無しと判断
○：１０人中６人以上が、多少臭気があるものの不快ではないと評価したので実用上問題無しと判断
×：１０人中５人以上が、臭気による不快感を訴えたため実用上問題有りと判断
〈印刷物が発する臭気〉
黒化面積率１２％の画像を文庫本用紙（６０．２ｇ／ｍ^２、平滑度２２秒）に両面印刷（プリント）し、Ｂ６サイズに裁断して２５０枚（５００ページ）の本に製本し、モニター本とした。
【０１２２】
１０〜５０代の１０人を無作為に選び、モニター本をめくったときに、印刷物が発する臭気を評価してもらった。
【０１２３】
評価基準
◎：１０人中８人以上が、臭気が気にならないと評価したので実用上問題無しと判断
○：１０人中６人以上が、多少臭気があるものの不快ではないと評価したので実用上問題無しと判断
×：１０人中５人上が、臭気による不快感を訴えたので実用上問題有りと判断
〈平滑な用紙の定着性〉
上記で製本したモニター本を片手親指で１０回めくり、文字周辺のにじみ状汚れを観察した。
【０１２４】
評価基準
◎：まったくにじみ状の汚れがなく実用上問題無しと判断
○：目視では、にじみ状汚れがない。ルーペで観察するとわずかに汚れが検知できるが実用上問題なしと判断。しかし、電子顕微鏡で観察すると、表面のトナー層が若干欠けている。
【０１２５】
×：親指の跡が、黒くにじんだように汚れているので実用上問題有りと判断
〈製造安定性〉
実施例１〜１０のトナーを各１０バッチ製造し、トナー粒子の体積平均粒径と帯電量のばらつきを評価した。
【０１２６】
体積平均粒径は、上記で製造したトナー１０バッチの各々を、「コールターカウンターＴＡ−ＩＩ型」（コールター株式会社製）で測定した。
【０１２７】
帯電量のばらつきは、上記で製造したトナー１０バッチの各々を、前記キャリアと混合し、トナー濃度６質量％の測定用試料を調製し、温度３０℃、相対湿度８０％ＲＨ環境下で帯電量を測定した。帯電量はブローオフ法で測定した。
【０１２８】
評価基準
◎：１０バッチの体積平均粒径がセンター値±０．１μｍ、帯電量がセンター±０．３μＣ／ｇでばらつきは非常に小さく実用上問題無しと判断
○：１０バッチの体積平均粒径がセンター値±０．２μｍ、帯電量がセンター値±０．６μＣ／ｇでばらつきは小さく実用上問題無しと判断
△：１０バッチの体積平均粒径がセンター値±０．５μｍ、帯電量がセンター値±１．０μＣ／ｇでばらつきはやや大きいが実用上問題無しと判断
×：１０バッチの体積平均粒径がセンター値±０．５μｍの範囲に入らず、帯電量がセンター値±１．０μＣ／ｇの範囲に入らずばらつきが大きかったので実用上問題有りと判断
表２に、プリント時の臭気、印刷物が発する臭気、平滑な用紙の定着性、製造安定性の評価結果を示す。
【０１２９】
【表２】

【０１３０】
本発明の「トナー１〜９」は、プリント時の臭気、印刷物が発する臭気、平滑な用紙の定着性、製造安定性のいずれも実用上問題がなかったが、比較例の「トナー１０」はプリント時の臭気、印刷物が発する臭気、平滑な用紙の定着性、製造安定性の全てについて問題があった。
【０１３１】
【発明の効果】
実施例で実証したごとく、本発明のトナー製造方法、トナーおよび濃縮液は、熱定着時に不快な臭気が発生せず、印刷物にも臭気が無く、オフセット印刷に見劣りしない画像堅牢性を有し、且つ製造安定性に優れた効果を有する。
【図面の簡単な説明】
【図１】本発明に用いられる遠心分離型濃縮装置の一例を示す断面図である。
【図２】本発明のトナーを用いる画像形成方法の一例を示す画像形成装置の断面構成図である。
【符号の説明】
１ 遠心分離装置本体
２ 上部部材
３ ロータ
４ 下部部材
５ 濃縮室
６ 接合部
１０ 沈降板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a toner obtained through a step of concentrating a resin particle dispersion, a toner, and a concentrate.
[0002]
[Prior art]
The mainstream of electrophotographic image formation has now shifted to digital systems. In digital image formation, for example, excellent fine line reproducibility and high resolution are typified by visualizing a small dot image at a level of, for example, 1200 dpi (the number of dots per inch, one inch is 2.54 cm). A small-diameter toner capable of exhibiting image properties is essential.
[0003]
JP-A-2002-296839 (see Patent Document 1) and JP-A-2002-351140 (see Patent Document 2) disclose, as an example of manufacturing such a small-diameter toner, a toner material such as a polyester resin. Discloses a method for producing a toner in which is emulsified and dispersed in an aqueous medium, and resin particles in the emulsified dispersion are aggregated to a toner size.
[0004]
However, the above-mentioned toner has a peculiar odor, and there is a problem that unpleasant odor is left in a room when a large amount is printed at a high speed.
[0005]
Further, as an embodiment of the above-described digital image formation, there is a print-on-demand type image formation method for performing printing “as many times as necessary when necessary”. Image formation by this method does not need to perform plate-making in conventional printing, it is possible to publish several hundred copies of publications and create direct mail and guide letters while changing the address, It is attracting attention as an effective image forming means replacing light printing.
[0006]
By the way, it has been found that the image formation by the electrophotographic method has a problem in creating a mail or a guide letter by changing the address described above. That is, when images are formed on thick paper such as bleeding cards, wedding invitations, postcards during mourning, or funeral ceremonies, sufficient fixing properties cannot be obtained. In particular, the postcards and funeral ceremonies during the mourning of the specifications provided with the gray frame hardly exhibited the fixing property in the gray frame portion, and the unfixed toner stained the user's hands and caused paper surface contamination.
[0007]
Also, when a toner image is formed on a thick paper surface, a large load is applied to the toner particles, which is incomparable with the case of outputting on paper such as copy paper, so that the toner particles are easily broken at the time of image formation, and are generated by the destruction. There is a problem that the paper surface is contaminated by the fine toner powder.
[0008]
Thick paper such as mourning postcards mentioned above is one of the most difficult transfer materials, but in order to spread electrophotography as a print-on-demand type image forming means, electrophotography must be used as a transfer material. It is necessary to be able to stably form a toner image on printing paper, not plain paper developed for printing. However, if these conditions were not met, the printing industry did not readily accept it.
[0009]
In particular, paperback paper has a high degree of smoothness and is suitable for offset printing, but the shear force is not concentrated on the toner image, and bleeding stains are often generated.
[0010]
For example, we often see scenes in which commuters read a paperback book with one hand while holding on to a strap during rush hour, but in such a situation it has `` slipperiness '' that turns pages with one hand, and toner against friction It is required to have "fixing strength" which does not stain paper and characters.
[0011]
That is, since the toner image formed by the electrophotographic method is inferior to the printed matter in terms of slipperiness and fixing strength, it has not been accepted by publishers and has been widely spread. The problem was not solved even when the toners disclosed in Patent Documents 1 and 2 were used.
[0012]
Further, since the process from dispersion to agglomeration of the raw material for the toner is performed consistently, it has been difficult to produce a toner having a constant average particle diameter and a non-uniform charge amount center value.
[0013]
In addition, in order to reduce the cost of installing and operating production equipment, the resin particle dispersion liquid produced at the place with hazardous material handling equipment is transferred to the place after the aggregation at the place with drainage equipment to produce toner. However, since the resin concentration (solid content concentration) in the resin particle dispersion is usually as low as 10 to 39% by mass, a large tank and a large storage space are required to store the resin particle dispersion, In addition, it is costly to transfer the resin particle dispersion, and it is difficult to reduce the toner price as a whole, and there is a problem.
[0014]
Also, when producing a special color toner that requires only a small amount, a large amount of the special color toner can be produced at one time due to integrated production, and the productivity of the special color toner is poor.
[0015]
[Patent Document 1]
JP-A-2002-296839 (see paragraph 0011)
[0016]
[Patent Document 2]
JP-A-2002-351140 (see paragraph 0011)
[0017]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above-described problems, and has as its object the purpose of not causing an unpleasant odor at the time of heat fixing, having no odor in printed matter, and having image fastness not inferior to offset printing. Another object of the present invention is to provide a toner production method, a toner and a concentrated solution which are excellent in production stability.
[0018]
[Means for Solving the Problems]
The object of the present invention is achieved by employing the following configuration.
[0019]
1. A method for producing a toner, comprising the steps of forming a resin particle dispersion obtained by dispersing resin particles in an aqueous medium, and aggregating the resin particles in the resin particle dispersion, wherein the resin particle dispersion is concentrated and concentrated. A method for producing a toner, comprising a step of preparing a liquid.
[0020]
2. 2. The method according to claim 1, wherein after adding water to the concentrate, the resin particles are aggregated.
[0021]
3. 3. A toner containing at least a binder resin and a colorant, wherein the toner is manufactured by the toner manufacturing method according to the above item 1 or 2.
[0022]
4. The average value of the circularity of the toner is 0.94 to 0.99, the average value of the equivalent circle diameter is 2.6 to 7.4 μm, and the inclination of the circularity with respect to the equivalent circle diameter is −0.050. 4. The toner according to the above item 3, wherein the toner particle size is from -0.010.
[0023]
5. A concentrated liquid obtained by removing at least water from a resin particle dispersion obtained by dispersing resin particles in an aqueous medium.
[0024]
6. Item 6. The concentrated liquid according to Item 5, wherein the solid content is 40 to 80% by mass.
[0025]
7. 7. The concentrate according to the above item 5 or 6, wherein the concentrate contains a polyester resin or a polyol resin.
[0026]
Hereinafter, the present invention will be described in detail.
The present inventors have prepared a concentrate obtained through a step of removing water (aqueous medium containing a compound serving as an odor generating source) from a resin particle dispersion obtained by dispersing resin particles in an aqueous medium, Thereafter, water is added to the concentrated liquid, and diluted to a concentration suitable for aggregation to prepare a resin particle redispersion liquid, by using a toner produced by aggregating the resin particles in the resin particle redispersion liquid, We have found that the above problem can be solved.
[0027]
Generally, removal of a compound that is a source of unpleasant odor of the toner is generally performed in a washing step or a drying step after forming the toner particles. According to the present invention, the dispersion before aggregation, that is, after removing the compound serving as an odor generating source in the aqueous medium in the stage of the resin particle dispersion liquid together with the aqueous medium to prepare a concentrated solution, if necessary, water is removed By using the resin particle redispersion liquid with the adjusted concentration and aggregating the resin particles to form toner particles, the compound serving as an odor generating source is reduced from being encapsulated inside the toner particles, and the generation of odor is reduced. Be suppressed.
[0028]
Further, since impurities (for example, insoluble salts and fatty acid salts) on the surface of the toner particles are removed, the crushing strength of the toner particles is greatly increased, and the image fastness against rubbing is improved.
[0029]
In addition, since the toner is manufactured in two stages of one-time storage with a concentrated solution and subsequent aggregation, manufacturing control is easy, manufacturing stability is increased, and costs for transport and storage of the resin particle separator can be reduced. As a result, the productivity of small-volume products is also improved.
[0030]
Specifically, after a toner material such as a polyester resin is emulsified and dispersed in an aqueous medium to prepare a resin particle dispersion, an aqueous medium containing impurities is removed from this dispersion to prepare a concentrated liquid. This concentrate is stored temporarily. Thereafter, the concentrated liquid is taken out in an amount required for the aggregating apparatus, and water is added to dilute the concentrated liquid to a concentration of resin particles suitable for aggregation to prepare a resin particle redispersion liquid. If necessary, a colorant, a release agent, a charge control agent, and the like are mixed with the resin particle redispersion liquid to perform aggregation to prepare aggregated particles. The aggregated particles are washed with water to further remove impurities in the aggregated particles, and dried to prepare toner particles. If necessary, an external additive is added to and mixed with the toner particles to produce a toner.
[0031]
The method for producing a toner via a concentrated solution provides a toner of good and stable quality, is efficient for small-quantity production, and can be shipped in a short time after the start of production if the concentrated solution is stored.
[0032]
The concentrate according to the present invention is prepared by removing water from the resin particle dispersion and concentrating the dispersion to a solid concentration of 40 to 80% by mass.
[0033]
In addition, in this invention, even if it looks like a paste, if a solid content density | concentration falls in the specific range of 40-80 mass%, it is called a concentrate.
[0034]
Hereinafter, a method for producing a toner using a concentrated solution will be specifically described.
<< Preparation of resin particle dispersion >>
The resin particle dispersion can be prepared by a known production method. Specifically, an emulsion association method using a vinyl monomer, a mini-emulsion polymerization method, a method in which a resin is dissolved in an organic solvent, emulsified, and then the solvent is removed. A method, a method of melting and emulsifying a resin at a high temperature, and the like can be exemplified, but are not particularly limited.
[0035]
However, in any method for producing a resin particle dispersion, it is preferable to lower the concentration of the resin particles in order to prepare fine resin particles. Therefore, the solid content concentration in the resin particle dispersion is usually 10 to 39 mass%. % And low concentration.
[0036]
<< Preparation of concentrate >>
A concentrated liquid can be prepared by removing water (aqueous medium containing a compound that is a source of odor) from the resin particle dispersion liquid. In this step, the solid content concentration in the dispersion is increased to 40 to 80% by mass. If the solid content is less than 40% by mass, the effect of removing the compound which is a source of unpleasant odor is small, and if it exceeds 80% by mass, the fluidity of the concentrated liquid is deteriorated, making it difficult to handle.
[0037]
The apparatus for removing water from the resin particle dispersion to prepare a concentrated liquid is not particularly limited, and a known solid-liquid separation apparatus can be used. Specific examples include a centrifugal separation type concentrator (for example, a filter type, a disk type, a sharpless type, a basket type), a belt type concentrator, a solution cyclone device, a decanter device, and the like. Preferably, a centrifugal concentrator is used.
[0038]
Next, a method of preparing a concentrated solution using a centrifugal separation type concentration device will be described. FIG. 1 is a cross-sectional view showing an example of a centrifugal separation type (disk type) concentrator used in the present invention.
[0039]
In FIG. 1, a main body 1 of a centrifugal separation type (disk type) concentrator has a rotor 3 at the center thereof, and is integrally connected to the rotor 3 by a fastening ring in the axial direction. The main body 1 is composed of an upper member 2 and a lower member 4 in which two bowls are overlapped, and has an enrichment chamber 5 in which a sedimentation plate 10 described later is arranged. Further, the slurry concentrated in the concentration chamber 5 from the joint 6 between the upper member 2 and the lower member 4 is automatically discharged out of the apparatus.
[0040]
The centrifugal separation type (disk type) concentrator used in the present invention can concentrate the resin particles if the difference in specific gravity between the resin particles and the dispersion is 2% or more, and removes water from the resin particle dispersion. It is possible to prepare a concentrate in a very short time. The rotor 3 at the center of the apparatus has a conical sedimentation plate 10 arranged around it in such a shape that the umbrellas are overlapped at an interval of 0.5 to 1 mm. That is, the concentrated liquid can be efficiently prepared by disposing the sedimentation plate having an extremely short sedimentation distance.
[0041]
<< Preparation of resin particle redispersion liquid >>
Water is added to the concentrated liquid so as to have a solid content concentration (for example, 10 to 39% by mass) suitable for aggregating the resin particles, thereby preparing a resin particle redispersion liquid. The device for diluting water is not particularly limited, and a device having a stirring function used for coagulation in the next step can be used as it is.
[0042]
<< Preparation of toner particles >>
To the resin particle redispersion liquid, a solution in which an aggregating agent is dissolved is added, and the resin particles are aggregated. If necessary, an aggregation terminator (for example, sodium chloride) is added to terminate the aggregation, thereby preparing aggregated particles. Then, it is washed with water (removal of a flocculant and a flocculant), and dried to prepare toner particles.
[0043]
Hereinafter, a method for preparing toner particles by the emulsion association method will be described.
After preparing resin particles in an aqueous medium by an emulsion association method, aggregating the resin particles in the aqueous medium, forming an aggregated particle dispersion, performing solid-liquid separation, washing with water, and drying to prepare toner particles The method is disclosed in, for example, JP-A-2002-351142.
[0044]
Further, there is a method for preparing a resin particle disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904 by salting out / fusion in an aqueous medium. That is, this is a method of salting out, aggregating, and fusing a plurality of dispersed particles of a constituent material such as a resin particle and a colorant or a fine particle composed of a resin and a colorant.
[0045]
Specifically, after dispersing these in water using an emulsifier, salting out is performed by adding a coagulant having a critical coagulation concentration or more, and at the same time, heat fusion at a temperature equal to or higher than the glass transition temperature of the formed polymer itself. When the target particle size is reached, a large amount of water or an aqueous sodium chloride solution is added to stop the particle size growth, and the particles are further heated and agitated. This is to prepare a toner particle dispersion by smoothing the surface and controlling the shape. Here, a solvent such as alcohol which is infinitely soluble in water may be added together with the coagulant.
[0046]
The apparatus for solid-liquid separation of the toner particles from the toner particle dispersion to form a toner cake is not particularly limited as long as it can perform solid-liquid separation. Specifically, a disk-type centrifuge, a De Laval-type centrifuge A basket-type centrifuge, an extrusion-type centrifuge, a Nutsche, etc., but it is preferable to use a disk-type centrifuge.
[0047]
The washed toner cake is discharged from the basket-type centrifugal separator, and is dried in a drying step to form toner particles.
[0048]
Examples of the dryer for drying include a flash jet drier, a spray drier, a vacuum freeze drier, a reduced pressure drier and the like. Among them, a flash jet drier is preferable.
[0049]
The moisture content of the dried toner particles is preferably 5% by mass or less, more preferably 2% by mass or less.
[0050]
<< Production of toner by mixing external additives >>
This step is a step of adding and mixing an external additive to the toner particles prepared above to produce a toner.
[0051]
As a device for mixing the external additive, various known devices such as a Turbula mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used. Among them, a Henschel mixer is preferable.
[0052]
Next, the shape of the toner according to the present invention will be described.
The shape of the toner of the present invention is such that when 2,000 or more toner particles having a particle size of 1 μm or more are measured, the average value of the circularity (shape factor) represented by the following formula is 0.94 to 0.99, and more preferably 0.94 to 0.99. 0.94 to 0.98.
[0053]

Here, the equivalent circle is a circle having the same area as the projected image of the toner particles, and the equivalent circle diameter is the diameter of the equivalent circle.
[0054]
The circularity can be measured by FPIA-2000 (manufactured by Sysmec Corporation). At this time, the circle equivalent diameter is defined by the following equation.
[0055]
Circle equivalent diameter = 2 × (projected area of particle / π)^1/2
The shape of the toner of the present invention is such that the average value of the circle equivalent diameter is 2.6 to 7.4 μm, and the inclination of the circularity with respect to the circle equivalent diameter is −0.050 to −0.010. Features. More preferably, the average value of the equivalent circle diameter is 3.4 to 6.6 μm, and the inclination of the circularity with respect to the equivalent circle diameter is −0.040 to −0.020.
[0056]
The present inventors have made the transfer material to perform a transfer like a wedge on particles having a large mass and a low circularity, and transferred particles having a small diameter and a high circularity so as to fill the gap, and a close packing. An image was formed by adjusting the state. It was found that when this image was fixed, the toner particles sintered with each other, and good fixing strength was obtained.
[0057]
However, the effect was insufficient if the circularity and the equivalent circle diameter of the particles were discretely distributed.
[0058]
Then, the present inventors have derived for the first time the concept of continuously changing the degree of circularity with respect to the equivalent circle diameter, and have found that good fixing strength can be obtained even with thick paper.
[0059]
The inclination of the equivalent circle diameter is measured by measuring the equivalent circle diameter of the toner particles with a flow-type particle image analyzer FPIA-2000, and expressing the relationship with the corresponding circularity on the horizontal axis: equivalent circle diameter (μm) -vertical axis. Axis: drawn as a circularity, and looking at its first-order correlation (y = αx + b), α is the slope of the circle equivalent diameter.
[0060]
At this time, from the viewpoint of improving the uniformity of charging and the uniformity of halftone, R²(R 2) is preferably from 0.35 to 0.95. Here, R is represented by the following general formula (1).
[0061]
General formula (1)
R = A / B
In the formula, A and B each represent the following formula.
[0062]
A = nΣXY- (ΣXΣY)
B = (nΣX²− (ΣX)²) × ((nΣY²)-(ΣY)²)
X represents the equivalent circle diameter (μm), and Y represents the degree of circularity.
[0063]
Further, in order to produce a toner having an inclination of a circle equivalent diameter, spherical toner particles having a small particle diameter and irregular toner particles having a slightly larger particle diameter may be mixed. Alternatively, in the method for producing toner particles by associating resin particles described below, after adding an aggregating agent in the associating step, the shape of the stirring blade is appropriately selected, the stirring intensity is controlled, and a shear force is applied to the larger particles. As an easy condition, a method of shifting to a filtration and drying step may be used. Preferably, the toner production device and the above-mentioned flow type particle image analyzer are connected in-line, and the production is performed while monitoring the inclination α and adjusting the conditions appropriately.
[0064]
Preferably, after the coagulant is added, if the toner particles are further grown by 0.2 to 1.0 μm, for example, by re-adding the coagulant or adding a surfactant, it is possible to control the toner particles to fall within the range of the present invention. I can do it.
[0065]
Next, an image forming method and an image forming apparatus used in the present invention will be described.
FIG. 2 is a sectional view of an image forming apparatus showing an example of an image forming method using the toner of the present invention.
[0066]
In FIG. 2, an image forming apparatus 101 includes an automatic document feeder (ADF) A, a document image reading unit B for reading an image of a document conveyed by the automatic document feeder, and processes the read document image. An image control board C, a writing unit D including a writing unit 112 for writing on a photosensitive drum 34 as an image carrier in accordance with data after image processing, a photosensitive drum 34 and a charger 35, a magnetic brush An image forming unit E including image forming means such as a developing device 36, a transfer device 37, a separator 39, and a cleaning device 41, which are formed by a mold developing device, and a storage unit for paper feed trays 122 and 124 for storing recording paper P. F.
[0067]
The main components of the automatic document feeder A include a document placing table 126 and a document feed processing unit 128 including a roller group including a roller R1 and switching means for appropriately switching a document moving path (no reference symbol). .
[0068]
The document image reading unit B is located below the platen glass G, and can move back and forth while maintaining the optical path length, two fixed mirror units 130 and 131, a fixed imaging lens (hereinafter simply referred to as a lens) 133, and a line-shaped image sensor. The writing unit D includes a laser light source 31, a polygon mirror (polarizer) 32, and the like.
[0069]
When viewed from the moving direction of the recording paper P as the transfer material, R10 shown on the front side of the transfer unit 37 is a registration roller, and H shown on the downstream side of the separator 39 is a fixing unit.
[0070]
In the embodiment, the fixing unit H includes a roller having a built-in heating source, and a pressing roller that rotates while pressing against the roller.
[0071]
Further, Z is a cleaning unit for the fixing unit H, and a cleaning web provided so as to be wound up is a main element.
[0072]
One document (not shown) placed on the document table 126 is transported by the document transport processing unit 128, and is exposed by the exposure unit L while passing under the roller R1.
[0073]
The reflected light from the document is imaged on the CCD 135 via the mirror units 130 and 131 and the lens 133 at the fixed position, and is read.
[0074]
The image information read by the document image reading unit B is processed by the image processing means, encoded, and stored in a memory provided on the image control board C.
[0075]
Further, the image data is called in accordance with the image formation, and the laser light source 31 in the writing section D is driven according to the image data, so that the photosensitive drum 34 is exposed.
[0076]
In recent years, in the field of electrophotography, etc., in which an electrostatic latent image is formed on a photoreceptor and this latent image is developed to obtain a visible image, it is easy to improve image quality, convert, edit, etc., and form high quality images. Research and development of image forming methods employing various digital methods have been actively conducted.
[0077]
As a scanning optical system that modulates light with a digital image signal from a computer or a copy original used in the image forming method and apparatus, an apparatus that interposes an acousto-optic modulator in a laser optical system and modulates light with the acousto-optic modulator is used. There is a device that directly modulates the laser intensity using a semiconductor laser, and spot-exposes a uniformly charged photoconductor from these scanning optical systems to form a dot-shaped image.
[0078]
The beam emitted from the above-described scanning optical system has a round or elliptical luminance distribution approximating a normal distribution with a skirt spreading left and right.For example, in the case of a laser beam, usually, the main scanning direction or on the photosensitive member. One or both of the sub-scanning directions have an extremely narrow round or elliptical shape of 20 to 100 μm.
[0079]
The toner according to the present invention is suitably used in an image forming method including a step of fixing an image forming support on which a toner image is formed by passing the image forming support between a heating roller and a pressure roller constituting a fixing device. You.
[0080]
【Example】
Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. In the following description, "parts" indicates parts by mass and "%" indicates mass%.
[0081]
<< Example 1 >>
<Preparation of concentrate 1>
(Preparation of latex (1HML))
(1) Preparation of core particles (first stage polymerization)
An anionic dispersion stabilizer in a 5000 ml separable flask equipped with a stirrer, temperature sensor, cooling tube, and nitrogen introduction device
Formula (101) C₁₀H₂₁(OCH₂CH₂)₂OSO₃Na
A dispersion stabilizer solution (aqueous medium) in which 7.08 g was dissolved in 3010 g of ion-exchanged water was charged, and the temperature in the flask was raised to 80 ° C. while stirring at a stirring speed of 230 rpm in a nitrogen stream.
[0082]
To this dispersion stabilizer solution was added an initiator solution obtained by dissolving 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water. A monomer mixture consisting of 19.9 g of butyl acrylate and 10.9 g of methacrylic acid was added dropwise over 1 hour, and the system was heated and stirred at 75 ° C. for 2 hours to polymerize (first stage polymerization). To prepare a latex (a dispersion of resin particles composed of a high molecular weight resin). This is designated as “latex (1H)”.
(2) Formation of intermediate layer (second stage polymerization)
In a flask equipped with a stirrer, a monomer mixture comprising 105.6 g of styrene, 30.0 g of n-butyl acrylate, 6.2 g of methacrylic acid, and 5.6 g of n-octyl-3-mercaptopropionate was separated. As a mold agent, 98.0 g of a compound represented by the following formula (hereinafter, referred to as “exemplary compound (19)”) was added, and the mixture was heated to 90 ° C. and dissolved to prepare a monomer solution.
[0083]
Exemplified compound (19)
CH₃(CH₂)₂₀COOCH₂C (CH₂OCO (CH₂)₂₀CH₃)₃
On the other hand, a dispersion stabilizer solution obtained by dissolving 1.6 g of an anionic dispersion stabilizer (formula (101)) in 2700 ml of ion-exchanged water is heated to 98 ° C., and a dispersion of core particles is added to this surfactant solution. After adding 28 g of the above-mentioned "latex (1H)" in terms of solid content, a mechanical dispersing machine having a circulation path "CLEARMIX (CLEARMIX)" (manufactured by M Technic Co., Ltd.) was used. The monomer solution was mixed and dispersed for 8 hours to prepare a dispersion liquid (emulsion liquid) containing emulsified particles (oil droplets) having a dispersion particle diameter of 284 nm.
[0084]
Next, to this dispersion liquid (emulsion liquid), an initiator solution obtained by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added. Polymerization (second-stage polymerization) was carried out by heating and stirring over time to obtain a latex (a dispersion of composite resin particles having a structure in which the surface of resin particles composed of a high molecular weight resin is coated with an intermediate molecular weight resin). This is referred to as “latex (1HM)”.
(3) Formation of outer layer (third stage polymerization)
An initiator solution obtained by dissolving 7.4 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water was added to the “latex (1HM)” obtained as described above, and styrene was added at a temperature of 80 ° C. A monomer mixture composed of 300 g, 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionate was added dropwise over 1 hour. After the completion of the dropping, polymerization (third stage polymerization) is carried out by heating and stirring for 2 hours, and then cooled to 28 ° C., and a latex (a central portion composed of a high molecular weight resin, an intermediate layer composed of an intermediate molecular weight resin, (1HML) having an outer layer made of a molecular weight resin, and the intermediate layer containing the exemplary compound (19). This latex (1HML) is referred to as “resin particle dispersion liquid 1”.
[0085]
The composite resin particles constituting the “resin particle dispersion 1” have peak molecular weights of 138,000, 80,000 and 13,000, and the mass average particle diameter of the composite resin particles is 122 nm. there were.
[0086]
Next, the “resin particle dispersion liquid 1” was subjected to a centrifugal separation (disk type) concentrating apparatus (sedimentation plate interval: 0.5 mm, total sedimentation plate area was 500 times the installation area of the apparatus) shown in FIG. The system was operated at 3000 rpm to remove water until the solid content concentration became 60% by mass to prepare “Concentrate 1”, which was temporarily stored in a transfer container (tank).
[0087]
<Preparation of Toner Particle 1>
The “concentrated liquid 1” in the transfer container was transferred to a stirring container equipped with an impeller by a pump, and diluted with water to prepare a “resin particle redispersion liquid 1” having a solid content concentration of 15% by mass.
[0088]
100 parts of "resin particle redispersion liquid 1"
12 parts of carbon black
1 part of charge control agent "Spiron Black TRH" (made by Hodogaya Chemical Co., Ltd.)
700 parts of ion exchange water
Sodium dodecylbenzenesulfonate 1 part
The above compound was stirred with an impeller of a stirring vessel and uniformly mixed.
[0089]
Next, "aqueous solution 1" obtained by dissolving 10 parts of aluminum chloride in 90 parts of ion-exchanged water is gradually dropped while stirring the impeller at a low speed to form aggregated particles. Thereafter, the liquid temperature is maintained at 70C. A part of the coalescence of aggregation was melted and confirmed by a scanning electron microscope.
[0090]
Thereafter, the mixture was stirred at 95 ° C. for 8 hours. When the circularity of the aggregated particles reached 0.963, water was added to cool the mixture to 40 ° C., and the stirring was stopped.
[0091]
Thereafter, washing and filtration were repeated, and the obtained cake was dried under reduced pressure to prepare black “toner particles 1”. The circularity was further increased by drying.
[0092]
<< Example 2 >>
<Preparation of concentrate 2>
In a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, 3430 parts of bisphenol A ethylene oxide 2 mol adduct, 1660 parts of isophthalic acid, and 20 parts of dibutyltin oxide are put and reacted at 230 ° C. for 8 hours under normal pressure. After further reacting at a reduced pressure of 10 to 15 mmHg (1.33 to 1.99 Pa) for 5 hours, the mixture was cooled to 110 ° C, and 17 parts of isophorone diisocyanate was added in toluene and reacted at 110 ° C for 5 hours. Subsequently, the solvent was removed to obtain a "urethane-modified polyester (2)" having a mass average molecular weight of 72,000 and a free isocyanate content of 0.7%. In the same manner as above, 5700 parts of a bisphenol A ethylene oxide 2 mol adduct and 2170 parts of terephthalic acid are polycondensed at 230 ° C. for 6 hours under normal pressure to be modified to have a number average molecular weight of 2,400, a hydroxyl value of 51 and an acid value of 5. No "polyester (2)" was obtained. 2,000 parts of "urethane-modified polyester (2)" and 8000 parts of "polyester (2)" were dissolved and mixed in 20,000 parts of ethyl acetate to obtain "Resin Solution 2" having a solid concentration of 15% by mass. A part of the “resin solution 2” was dried under reduced pressure to isolate a resin component. The Tg of the resin component was 55 ° C.
[0093]
In a beaker, 500 parts of water and 40 parts of nonylphenol ethylene oxide adduct “Nonipol 200” (manufactured by Sanyo Chemical Industries) were added and uniformly dissolved. While stirring at 18,000 rpm with a TK homomixer, “Resin Solution 2” was charged and stirred for 15 minutes. Then, this mixed solution was transferred to a reaction vessel equipped with a stirring rod and a thermometer, and the temperature was raised to distill off ethyl acetate. The temperature was further raised to 98 ° C., and the reaction was carried out for 5 hours to obtain “urethane-modified polyester (2)”. As a result, a “resin particle dispersion liquid 2” having a solid content concentration of 15% by mass and comprising a mixture of the water elongation reaction product and “polyester (2)” was obtained. The volume average particle diameter of the “resin particle dispersion liquid 2” measured by LA-920 was 0.21 μm. Further, a process of centrifuging a part of the “resin particle dispersion liquid 2”, adding water, and centrifuging the mixture twice was repeated, followed by drying to isolate a resin component. The Tg of the resin component was 64 ° C.
[0094]
Next, the "resin particle dispersion liquid 2" was centrifuged (disk type) concentrator (sedimentation plate interval 0.5 mm, the total sedimentation plate area was 500 times the installation area of the device) shown in FIG. By operating at 3000 rpm, water was removed until the solid content concentration reached 60% by mass to prepare "Concentrate 2", which was temporarily stored in a transfer container (tank).
[0095]
<Preparation of Toner Particle 2>
The “concentrated liquid 2” in the transfer container was transferred to a stirring container equipped with an impeller by a pump, and diluted with water to prepare a “resin particle redispersion liquid 2” having a solid content concentration of 15% by mass.
[0096]
"Resin particle redispersion liquid 2" 100 parts
12 parts of carbon black
1 part of charge control agent "Spiron Black TRH" (made by Hodogaya Chemical Co., Ltd.)
Carnauba wax 10 parts
700 parts of ion exchange water
Sodium dodecylbenzenesulfonate 1 part
The above compound was stirred with an impeller of a stirring vessel and uniformly mixed.
[0097]
Next, "aqueous solution 2" obtained by dissolving 10 parts of aluminum chloride in 90 parts of ion-exchanged water is gradually dropped while stirring the impeller at a low speed to form aggregated particles. Thereafter, the liquid temperature is maintained at 70 ° C. A part of the coalescence of aggregation was melted and confirmed by a scanning electron microscope.
[0098]
Thereafter, the mixture was stirred at 95 ° C. for 8 hours. When the circularity of the aggregated particles reached 0.963, water was added to cool the mixture to 40 ° C., and the stirring was stopped.
[0099]
Thereafter, washing with water and filtration were repeated, and the obtained cake was dried under reduced pressure to obtain black “toner particles 2”. The circularity was further increased by drying.
[0100]
<< Example 3 >>
<Preparation of concentrate 3>
343 parts of bisphenol A ethylene oxide 2 mol adduct, 166 parts of isophthalic acid and 2 parts of dibutyltin oxide are placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introducing tube, and reacted at 230 ° C. for 8 hours under normal pressure. After further reacting at a reduced pressure of 10 to 15 mmHg (1.33 to 1.99 Pa) for 5 hours, the mixture was cooled to 110 ° C, and 17 parts of isophorone diisocyanate was added in toluene and reacted at 110 ° C for 5 hours. Subsequently, the solvent was removed to obtain a "urethane-modified polyester (3)" having a weight average molecular weight of 72,000 and a free isocyanate content of 0.7%. In the same manner as above, 570 parts of a bisphenol A ethylene oxide 2 mol adduct and 217 parts of terephthalic acid are polycondensed at 230 ° C. for 6 hours under normal pressure to be modified to have a number average molecular weight of 2,400, a hydroxyl value of 51 and an acid value of 5. No "polyester (3)" was obtained. 200 parts of "urethane-modified polyester (3)" and 800 parts of "polyester (3)" were dissolved and mixed in 2,000 parts of ethyl acetate to obtain "Resin Solution 3" having a solid content of 15% by mass. A part of the “resin solution 3” was dried under reduced pressure to isolate a resin component. The Tg of the resin component was 55 ° C.
[0101]
"Resin solution 3" 100 parts
12 parts of carbon black
1 part of charge control agent "Spiron Black TRH" (made by Hodogaya Chemical Co., Ltd.)
Carnauba wax 10 parts
The above-mentioned material was dissolved and dispersed by rolling a ball mill filled with zirconia beads in 200 parts of toluene to prepare "oil phase 3" as a dispersed phase.
[0102]
Separately,
700 parts of ion exchange water
Sodium dodecylbenzenesulfonate 1 part
Was stirred and dispersed to prepare “aqueous phase 3” to be a continuous phase. The “oil phase 3” was charged into the “aqueous phase 3” while being stirred by a “homomixer” (manufactured by Tokushu Kika Kogyo Co., Ltd.), and the stirring speed was adjusted to adjust the volume average particle diameter of about 1 μm. An oil drop 3 "was prepared. Thereafter, toluene was removed by distillation under reduced pressure at 50 ° C. to obtain a black “resin particle dispersion liquid 3” having a solid concentration of 15% by mass.
[0103]
Next, the “resin particle dispersion 3” was centrifuged (disk-type) concentrator (sedimentation plate interval 0.5 mm, total sedimentation plate area was 500 times the installation area of the device) shown in FIG. The system was operated at 3000 rpm to remove water until the solid content concentration became 60% by mass to prepare “Concentrate 3”, which was temporarily stored in a transfer container (tank).
[0104]
<Preparation of Toner Particle 3>
The “concentrated liquid 3” in the transfer container was transferred by a pump to a fixed amount of a stirring container equipped with an impeller, and diluted with water to prepare “resin particle redispersed liquid 3” having a solid content concentration of 15% by mass.
[0105]
Next, "aqueous solution 3" obtained by dissolving 10 parts of aluminum chloride in 90 parts of ion-exchanged water is gradually dropped while stirring the impeller at a low speed to form aggregated particles. Thereafter, the liquid temperature is maintained at 70C. A part of the coalescence of aggregation was melted and confirmed by a scanning electron microscope.
[0106]
Thereafter, the mixture was stirred at 95 ° C. for 8 hours. When the circularity of the aggregated particles reached 0.963, the mixture was cooled to 40 ° C. and the stirring was stopped.
[0107]
Thereafter, washing with water and filtration were repeated, and the obtained cake was dried under reduced pressure to produce black “toner particles 3”. The circularity was further increased by drying.
[0108]
<< Example 4 >>
Example 3 Example 3 was repeated except that the solid content concentration of the “concentrated liquid 3” in Example 3 was changed from 60% by mass to 50% by mass, and the solid content concentration of the “resin particle redispersion liquid 3” was changed from 15% by mass to 20% by mass. “Toner particles 4” were prepared in the same manner as in “3.
[0109]
<< Example 5 >>
Example 3 was repeated except that the solid content concentration of the “concentrated liquid 3” in Example 3 was changed to 60% by mass and the solid content concentration of the “resin particle redispersion liquid 3” was changed from 15% by mass to 20% by mass. Similarly, “toner particles 5” were prepared.
[0110]
<< Example 6 >>
Example 3 Example 3 was repeated except that the solid content concentration of the “concentrated liquid 3” in Example 3 was changed from 60% by mass to 75% by mass, and the solid content concentration of the “resin particle redispersion liquid 3” was changed from 15% by mass to 20% by mass. “Toner particles 6” were prepared in the same manner as in “3.
[0111]
<< Example 7 >>
“Toner particles 7” were prepared in the same manner as in Example 3, except that the concentration of the solid content of “Concentrated solution 3” in Example 3 was changed to 60% by mass and the dilution with water was not performed.
[0112]
<< Embodiment 8 >>
Example 3 Example 3 was repeated except that the solid content concentration of the “concentrated liquid 3” in Example 3 was changed from 60% by mass to 80% by mass, and the solid content concentration of the “resin particle redispersion liquid 3” was changed from 15% by mass to 30% by mass. "Toner particles 8" were prepared in the same manner as in No. 3.
[0113]
<< Example 9 >>
The “resin particle dispersion 3” of Example 3 was dried to a water content of 0.5% by mass with a flash dryer, and then diluted with water to prepare a “resin particle redispersion 9” having a solid content concentration of 15% by mass. Except for the above, “toner particles 9” were prepared in the same manner as in Example 3.
[0114]
<< Example 10 >>
"Colored particles 10" were prepared in the same manner as in Example 3 except that the "resin particle dispersion 3" of Example 3 was not concentrated.
[0115]
Table 1 shows the solid content concentration of the resin particle dispersion, the solid content concentration of the concentrated solution, the solid content concentration of the resin particle redispersion solution, the average value of the circularity, the average value of the circle equivalent diameter, and the circularity relative to the circle equivalent diameter. Shows the slope.
[0116]
[Table 1]

[0117]
<Preparation of toner>
100 parts of each of "toner particles 1 to 10" prepared in Examples and 0.5 part of hydrophobic silica R972 (primary particle diameter: 16 nm: manufactured by Nippon Aerosil Co., Ltd.) were mixed by a Henschel mixer, and sieved with a sieve having openings of 50 μm. Coarse particles and aggregates were removed to prepare “Toners 1 to 10”.
[0118]
<Preparation of developer>
Each of the “toners 1 to 10” produced as described above and a “carrier” coated with manganese ferrite of 60 μm by silicone were mixed using a Henschel mixer, and “developers 1 to 10” having a toner concentration of 6% by mass were mixed. Was prepared.
[0119]
《Evaluation》
"Developers 1 to 10" are sequentially set in a commercially available electrophotographic digital multifunction copying machine "Sitios 7075HV" (manufactured by Konica Corporation), and printing is performed using "toners 1 to 10", and the following items are evaluated. Was done.
[0120]
<Odor during printing>
Ten people engaged in the light printing industry were asked to monitor and evaluated the degree of odor generated from the fixing part when 5,000 continuous A4 size images with 12% blackening area were printed. Was.
[0121]
Evaluation criteria
◎: Eight or more of the ten persons evaluated that the odor was not annoying, so it was judged that there was no practical problem.
：: 6 or more out of 10 evaluated that there was some odor but it was not uncomfortable, so there was no practical problem
×: Five or more out of ten complained of discomfort due to odor and judged that there was a practical problem
<Odor from printed matter>
An image with a blackening area ratio of 12% was applied to paperback paper (60.2 g / m2).²(Smoothness: 22 seconds), and cut into B6 size, bound into 250 (500 pages) books, and used as monitor books.
[0122]
Ten people in their teens and fifties were randomly selected and asked to evaluate the odor emitted by the printed matter when turning over the monitor book.
[0123]
Evaluation criteria
◎: Eight or more of the ten persons evaluated that the odor was not annoying, so it was judged that there was no practical problem.
：: 6 or more out of 10 evaluated that there was some odor but it was not uncomfortable, so there was no practical problem
×: Five out of 10 complained of discomfort due to odor, so it was judged that there was a problem in practice
<Smooth paper fixability>
The book bound in the above manner was turned ten times with one thumb, and bleeding stains around the characters were observed.
[0124]
Evaluation criteria
◎: Judged that there was no bleeding-like stain and no practical problem
：: No bleeding is observed visually. Slight dirt can be detected when observed with a loupe, but it is judged that there is no practical problem. However, when observed with an electron microscope, the toner layer on the surface is slightly missing.
[0125]
×: It is judged that there is a practical problem because the thumb mark is stained as if it is smeared black.
<Manufacturing stability>
Ten batches of each of the toners of Examples 1 to 10 were produced, and the variations in the volume average particle diameter and the charge amount of the toner particles were evaluated.
[0126]
The volume average particle diameter was measured for each of the ten batches of the toner produced above using a “Coulter Counter TA-II” (manufactured by Coulter Corporation).
[0127]
The variation in the charge amount was determined by mixing each of the 10 batches of toner produced above with the carrier, preparing a measurement sample having a toner concentration of 6% by mass, and measuring the charge amount at a temperature of 30 ° C. and a relative humidity of 80% RH. Was measured. The charge amount was measured by a blow-off method.
[0128]
Evaluation criteria
：: The volume average particle diameter of 10 batches was ± 0.1 μm at the center value, and the charge amount was ± 0.3 μC / g at the center.
：: The volume average particle size of 10 batches was ± 0.2 μm in center value, and the charge amount was ± 0.6 μC / g in center value.
Δ: The volume average particle size of 10 batches was ± 0.5 μm in center value, and the charge amount was ± 1.0 μC / g in center value.
×: The volume average particle size of the 10 batches did not fall within the range of the center value ± 0.5 μm, and the charge amount did not fall within the range of the center value ± 1.0 μC / g.
Table 2 shows the evaluation results of the odor at the time of printing, the odor emitted from the printed matter, the fixability of smooth paper, and the production stability.
[0129]
[Table 2]

[0130]
"Toner 1 to 9" of the present invention had no practical problems in odor at the time of printing, odor emitted from printed matter, fixability of smooth paper, and production stability, but "Toner 10" of Comparative Example There are problems with the odor at the time of printing, the odor emitted from the printed matter, the fixability of smooth paper, and the production stability.
[0131]
【The invention's effect】
As demonstrated in the examples, the toner production method of the present invention, the toner and the concentrated solution do not generate an unpleasant odor during heat fixing, have no odor in the printed matter, and have image fastness not inferior to offset printing, In addition, it has an effect of excellent production stability.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of a centrifugal separation type concentrator used in the present invention.
FIG. 2 is a cross-sectional configuration diagram of an image forming apparatus showing an example of an image forming method using the toner of the present invention.
[Explanation of symbols]
1 Centrifuge body
2 Upper member
3 rotor
4 Lower member
5 Concentration room
6 Joints
10 Settling plate

Claims (7)

A method for producing a toner, comprising the steps of forming a resin particle dispersion obtained by dispersing resin particles in an aqueous medium, and aggregating the resin particles in the resin particle dispersion, wherein the resin particle dispersion is concentrated and concentrated. A method for producing a toner, comprising a step of preparing a liquid. The method according to claim 1, wherein after adding water to the concentrated liquid, the resin particles are aggregated. A toner containing at least a binder resin and a colorant, wherein the toner is manufactured by the toner manufacturing method according to claim 1. The average value of the circularity of the toner is 0.94 to 0.99, the average value of the equivalent circle diameter is 2.6 to 7.4 μm, and the inclination of the circularity with respect to the equivalent circle diameter is −0.050. The toner according to claim 3, wherein the value is from −0.010 to −0.010. A concentrated liquid obtained by removing at least water from a resin particle dispersion obtained by dispersing resin particles in an aqueous medium. The concentrate according to claim 5, wherein the solid content is 40 to 80% by mass. The concentrate according to claim 5, wherein the concentrate includes a polyester resin or a polyol resin.

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