JP4467036B2 - Toner production method - Google Patents

Description

【０２０４】
【化２】

【０２０５】
また、本発明では離型剤として結晶性ポリエステルも用いることができるものであるが、結晶性ポリエステルとしては、脂肪族ジオールと、脂肪族ジカルボン酸（酸無水物および酸塩化物を含む）とを反応させて得られるポリエステルが好ましい。
【０２０６】
結晶性ポリエステルを得るために使用されるジオールとしては、エチレングリコール、ジエチレングリコール、トリエチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，４−ブタンジオール、１，４−ブテンジオール、ネオペンチルグリコール、１，５−ペンタングリコール、１，６−ヘキサンジオール、１，４−シクロヘキサンジオール、１，４−シクロヘキサンジメタノール、ジプロピレングリコール、ポリエチレングリコール、ポリプロピレングリコール、ポリテトラメチレングリコール、ビスフェノールＡ、ビスフェノールＺ、水素添加ビスフェノールＡ等を挙げることができる。
【０２０７】
結晶性ポリエステルを得るために使用されるジカルボン酸としては、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スペリン酸、アゼライン酸、セバシン酸、マレイン酸、フマール酸、シトラコ酸、イタコン酸、グルタコ酸、ｎ−ドデシルコハク酸、ｎ−ドデセニルコハク酸、イソドデシルコハク酸、イソドデセニルコハク酸、ｎ−オクチルコハク酸、ｎ−オクテニルコハク酸、これらの酸無水物あるいは酸塩化物を挙げることができる。
【０２０８】
特に好ましい結晶性ポリエステルとしては、１，４−シクロヘキサンジメタノールとアジピン酸とを反応して得られるポリエステル、１，６−ヘキサンジオールとセバシン酸とを反応して得られるポリエステル、エチレングリコールとコハク酸とを反応して得られるポリエステル、エチレングリコールとセバシン酸とを反応して得られるポリエステル、１，４−ブタンジオールとコハク酸とを反応して得られるポリエステルを挙げることができ、これらのうち、１，４−シクロヘキサンジメタノールとアジピン酸とを反応して得られるポリエステルが最も好ましい。
【０２０９】
上記化合物の添加量は、トナー全体に対し１質量％〜３０質量％、好ましくは２質量％〜２０質量％、更に好ましくは３質量％〜１５質量％である。
【０２１０】
（現像剤）
本発明で製造されるトナーは、二成分現像剤として用いられる。すなわち、トナーとキャリアとを混合した二成分現像剤である。この場合、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いることが出来る。特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５μｍ〜１００μｍ、より好ましくは２５μｍ〜８０μｍのものがよい。
【０２１１】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０２１２】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン−アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレン−アクリル系樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０２１３】
【実施例】
以下、本発明の構成と効果を説明するため、実施例として具体的な態様を示して説明するが、本発明の態様はこれに限定されるものではない。
樹脂粒子の製造
〔樹脂粒子（１ＨＭＬ）〕
（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界面活性剤
化合物（１０１） Ｃ₁₀Ｈ₂₁（ＯＣＨ₂ＣＨ₂）₂ＯＳＯ₃Ｎａ
７．０８ｇをイオン交換水３０１０ｇに溶解させた界面活性剤溶液（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。
【０２１４】
この界面活性剤溶液に、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、樹脂粒子（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「樹脂粒子（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、結晶性物質として、前記の１９）で表される化合物（以下、「例示化合物（１９）」という。）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。
【０２１５】
一方、アニオン系界面活性剤（化合物（１０１））１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を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樹脂粒子（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）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、乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２１６】
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、樹脂粒子（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「樹脂粒子（１ＨＭ）」とする。
【０２１７】
前記樹脂粒子（１ＨＭ）を乾燥し、走査型電子顕微鏡で観察したところ、ラテックスに取り囲まれなかった例示化合物（１９）を主成分とする粒子（４００〜１０００ｎｍ）が観察された。
（３）外層の形成（第三段重合）：
上記の様にして得られた樹脂粒子（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℃まで冷却し樹脂粒子（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）の分散液を得た。この樹脂粒子を「樹脂粒子（１ＨＭＬ）」とする。
【０２１８】
この樹脂粒子（１ＨＭＬ）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。
〔樹脂粒子（２ＨＭＬ）〕
界面活性剤（１０１）に代えて、アニオン系界面活性剤（ドデシルベンゼンスルフォン酸ナトリウム：ＳＤＳ）７．０８ｇを使用したこと以外は、樹脂粒子（１ＨＭＬ）と同様にして、樹脂粒子（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する複合樹脂粒子の分散液）を得た。この樹脂粒子を「樹脂粒子（２ＨＭＬ）」とする。
【０２１９】
この樹脂粒子（２ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１２，０００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。
〔樹脂粒子（３ＨＭＬ）〕
界面活性剤（１０１）に代えて、アニオン系界面活性剤（ドデシルベンゼンスルフォン酸ナトリウム：ＳＤＳ）７．０８ｇを使用したこと以外は、樹脂粒子（１ＨＭＬ）と同様にして、樹脂粒子（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する複合樹脂粒子の分散液）を得た。この樹脂粒子を「樹脂粒子（３ＨＭＬ）」とする。
【０２２０】
この樹脂粒子（３ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１２，０００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１１０ｎｍであった。
濃縮したトナー粒子分散液（ウェットケーキ）の調製
アニオン系界面活性剤（ドデシル硫酸ナトリウム）５９．０ｇをイオン交換水１６００ｍｌに攪拌溶解し、この溶液を攪拌しながら、カーボンブラック４２０．０ｇ徐々に添加し、次いで「クレアミックス」（エム・テクニック（株）製）を用いて分散処理することにより、着色剤粒子の分散液を調製した。
【０２２１】
樹脂粒子（１ＨＭＬ）４２０．７ｇ（固形分換算）と、イオン交換水９００ｇと、着色剤分散液１６６ｇとを、温度センサー、冷却管、窒素導入装置、攪拌装置を取り付けた反応容器（四つ口フラスコ）に入れ攪拌した。容器内の温度を３０℃に調整した後、この溶液に５ｍｏｌ／リットルの水酸化ナトリウム水溶液を加えてｐＨを８に調整した。
【０２２２】
次いで、表１の組み合わせで塩析剤をイオン交換水１０００ｍｌに溶解した水溶液を、攪拌下、３０℃にて１０分間かけて添加した。
【０２２３】
【表１】

【０２２４】
３分間放置した後に昇温を開始し、この系を３０分間かけて９０℃まで昇温し、粒子の成長を開始した。「コールターカウンター マルチサイザー」にて成長した粒子の粒径を測定し、体積平均粒径が３μｍになった時点で、塩析停止剤をおなじく表１の組み合わせでイオン交換水１０００ｍｌに溶解した水溶液を添加し粒子成長を停止させた。更に熟成処理として液温度９８℃にて２時間にわたり加熱攪拌することにより、粒子の融着を継続させた。
【０２２５】
その後、３０℃まで冷却し、攪拌を停止して、体積平均粒径が４．５μｍの粒子状の固形物を２０質量％含有するトナー粒子分散液を得た。
【０２２６】
実施例１（トナー１の製造）
▲１▼トナー粒子の濃縮工程
上記トナー粒子分散液を図１に示す沈降板間隔０．５ｍｍ、装置設置面積に対する全沈降板の面積が５００倍のディスク型遠心沈降装置に投入し、回転数を３０００ｒｐｍに設定、作動させて、トナー粒子分散液を濃縮した。なお、この時の遠心力は１１０００Ｇであった。濃縮して得られたトナー粒子分散液は、固形分含有率が５０％のウェットケーキと呼ばれる状態にあるもので、濃縮したトナー粒子分散液を８２３ｇ得た。得られた濃縮したトナー粒子分散液をウェットケーキ１とする。なお、この時の濃縮を行った際の所要時間はトナー粒子分散液１リットルあたり０．４秒であった。
▲２▼ウェットケーキ１の再分散及び再濃縮工程
ウェットケーキ１を洗浄媒体であるイオン交換水１００００ｍｌに投入し、同時に塩酸を含有する水溶液を添加してｐＨを２．０に調整し、攪拌翼を用いて３０分間分散させてトナー粒子分散液を生成した。得られたトナー粒子分散液の電気伝導度を東亜電波工業（株）社製の「ＣＭ−１４Ｐ」を電気伝導度計で測定を行い、トナー粒子分散液の電気伝導度の値が１５μＳ／ｃｍ以下になるまで、上記ディスク型遠心沈降装置によるトナー粒子分散液の濃縮と再分散を繰り返した。
▲３▼最終調製工程
最終的に電気伝導度の値が、１５μＳ／ｃｍ以下になった時のウェットケーキ１よりトナー粒子を取り出し、透過型電子顕微鏡にてトナー粒子１００個についてその表面における不純物付着状況を確認した。確認の結果、粒子１００個中に不純物付着した粒子は１個であることが確認された。
▲４▼乾燥工程
その後、バットに移したウェットケーキ１をオーブン型乾燥機に入れて、４０℃の温風で水分量が０．６３％になるまで乾燥した。
▲５▼外添工程
乾燥した着色粒子を疎水性シリカ１質量％と混合することにより、トナーを得た。得られたトナーをトナー１とする。
【０２２７】
実施例２〜５（トナー２〜５の製造）
上記ディスク型遠心沈降装置の沈降板間隔を１．０ｍｍ、装置設置面積に対する全沈降板の面積を２００倍とした以外は、実施例１と同様にしてトナー粒子分散液の濃縮と再分散を繰り返しトナー２を得た。なお、この時のトナー粒子分散液１リットルあたりの処理時間は０．８秒であった。
【０２２８】
同様に、沈降板間隔を０．２５ｍｍ、装置設置面積に対する全沈降板の面積を１０００倍として得られたものをトナー３、２．０ｍｍ、１００倍で得られたものをトナー４、１０ｍｍ、１０倍に設定して得られたものをトナー５とした。トナー３、４、５のトナー粒子分散液１リットルあたりの平均処理時間は、それぞれ０．２秒、１．５秒、３．５秒だった。各トナー１００個中の不純物粒子の数を表２に示す。
【０２２９】
実施例６、７（トナー６、７の製造）
上記実施例１における粒子の体積平均粒径が３μｍ後の熟成を行わなかった他は実施例１と同様にしてトナー６を得た。また、熟成処理を継続して液温度９８℃で加熱撹拌を延長して粒子の融着を継続させた他は実施例１と同様にしてトナー７を得た。各トナー１００個中の不純物粒子の数を表２に示す。
【０２３０】
実施例８〜１３（トナー８〜１３の製造）
上記実施例１におけるトナー粒子のウェットケーキ１を洗浄媒体に投入する時の洗浄液のｐＨを４．５とした他は実施例１と同様の手順でトナー８を得た。また、洗浄液のｐＨを６．５としてトナー９を得た。
【０２３１】
更に、水酸化ナトリウムを添加してｐＨを８、１０、１２、１４とした洗浄液を使用して得られたトナーを１０、１１、１２、１３とした。得られた各トナーにおける粒子１００個当たりの不純物付着量を表２に示す。
【０２３２】
比較例１（比較用トナー１）
実施例１において、▲１▼〜▲３▼の工程を省いた以外は同様にして比較用トナー１を得た。得られたトナー１００個中の不純物粒子の数を表２に示す。
【０２３３】
比較例２（比較用トナー２）
実施例１において、遠心沈降装置に代わって、得られたトナー粒子分散液を不織布製の濾布がセットされた遠心分離機の槽内に入れ、加速度が７００Ｇの条件で遠心分離機を作動してトナー粒子分散液の濃縮を行う工程を経て比較用トナー２を得た。得られたトナー１００個中の不純物粒子の数を表２に示す。
【０２３４】
比較例３（比較用トナー３）
実施例１において、遠心沈降装置に代わり、特開２００１−１９４８２６号公報に記載のデカンタ型遠心分離機を使用して、トナー粒子分散液の濃縮を行う工程を経て比較用トナー３を得た。得られたトナー１００個中の不純物粒子の数を表２に示す。
【０２３５】
上記トナーの性能を表２に示す。なお、表２中において、トナー粒子の体積平均粒径はコールターカウンターＴＡ−IIにより測定したものであり、粒子１００個あたりの不純物含有量は透過型電子顕微鏡写真により評価した。
【０２３６】
【表２】

【０２３７】
表２の結果より明らかな様に、本発明に係る製造方法によって得られたトナー粒子表面には不純物が除去されていることが確認された。
【０２３８】
実写評価
画像形成装置としては市販のデジタル複写機Ｓｉｔｉｏｓ７１６５（コニカ社製）を用いた。上記デジタル複写機は、以下の条件に設定し評価を行った。
【０２３９】
帯電条件
帯電器；スコロトロン帯電器、初期帯電電位を−７５０Ｖ
露光条件
露光部電位を−５０Ｖにする露光量に設定した
現像条件
ＤＣバイアスを−５５０Ｖに設定した
転写条件
コロナ帯電方式。
【０２４０】
また、定着装置としては、芯金として鉄を使用し、表面を厚さ２５μｍのＰＦＡ（テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合体）で被覆された表面粗さＲａが０．８μｍの加熱ローラーを使用し、加圧ローラーとして鉄の芯金を使用し、ＨＴＶシリコーンゴムの上に厚み１２０μｍのＰＦＡチューブを被覆した表面粗さＲａが０．８μｍの加圧ローラーを用いた。なお、ニップ幅は３．８ｍｍであり、線速は４２０ｍｍ／ｓｅｃである。
【０２４１】
なお、定着装置のクリーニング機構及びシリコンオイル供給機構は装着していない。定着の温度は加熱ローラーの表面温度で制御し、１６５℃の設定温度とした。
【０２４２】
現像剤としては体積平均粒径６０μｍのシリコーンコートキャリアを用い、トナー質量濃度が６％となるようにそれぞれのトナーと混合し用いた。
【０２４３】
複写条件は、高温高湿環境（３０℃、８３％ＲＨ）にて連続１００万枚のプリント行い、連続１００万枚プリント後のコピー画像について、以下の項目についての評価を行った。なお、コピー画像は、Ａ４サイズ黒化面積率５％の文字原稿を使用し、Ａ４の転写紙に等倍で印字した。
（１）帯電量の経時変化
現像剤をセットして１枚目の画像を出したときの帯電量をＱａ、１００万枚の画像を出したときの帯電量をＱｂとし、Ｑｂ／Ｑａが
◎：０．９以上１．１未満
○：０．８以上０．９未満、又は１．１以上１．２未満
△：０．７以上０．８未満、又は１．２以上１．３未満
×：０．７未満又は１．３以上
（２）感光体フィルミング
前述の連続１００万枚コピー後の感光体表面を目視にて観察するとともに、フィルミングによるハーフトーンのむらの有無を判定した。
【０２４４】
◎：ムラのない均一な画像が得られ、フィルミング発生は見られない
○：スジ状の薄いムラが存在するが、実用上問題なし、又感光体表面上のフィルミング発生は認められない
△：スジ状の薄いムラが存在し、感光体表面に若干のフィルミング発生が確認されるが実用上問題なし
×：スジ状のはっきりしたムラが数本以上存在し、感光体表面にはっきりしたフィルミングが認められ、実用上問題あり。
（３）カブリ
連続１００万コピー後のコピー画像画像部白地部分における未使用転写シートに対する相対濃度を、マクベス濃度計を用いて測定した。
【０２４５】
◎：相対濃度０〜０．００２未満
○：相対濃度０．００２以上０．００３未満
△：相対濃度０．００３以上０．００５未満
×：相対濃度０．００５以上。
（３）クリーニング不良
クリーニング部からのトナーすり抜けによる白地部分を汚染開始したコピー枚数で評価した。
（４）網点再現性
２０ｍｍ×２０ｍｍの１０％網点画像部についてのマクベス反射濃度計「ＲＤ−９１８」により、１枚目と１００万枚目のドットの再現性を評価した。濃度変化が０．１０未満であれば画質変化は少なく問題なしと評価した。
（５）ライン幅
２ドットラインの画像信号に対応するライン画像のライン幅を印字評価システム「ＲＴ２０００」（ヤーマン（株）製）により再生再現性を評価した。評価は１枚目及び１００万枚目のライン画像のライン幅とライン幅の変動について評価した。
【０２４６】
◎：１枚目と１００万枚目のライン幅がいずれも２００μｍ以下で、ライン幅の変化が０〜５μｍ未満
○：１枚目と１００万枚目のライン幅はいずれも２００μｍ以下で、ライン幅変化が５μｍ以上１０μｍ未満
△：１枚目のライン幅は２００ミクロンを若干オーバーするが、１００万枚目のライン幅は２００μｍ以下で、ライン幅変化は１０μｍ未満
×：１枚目と１００万枚目のライン幅はいずれも２００μｍを超え、かつライン幅の変化が１０μｍを超えるもの
（６）文字つぶれ
１００万枚コピー後に、３ポイントと５ポイントの文字画像を形成し、下記の判断基準でルーペを使用して評価した。
【０２４７】
◎：３ポイント、５ポイントとも明瞭で、容易に判読可能
○：３ポイントは一部判読不能な文字が発生するがルーペで判読可能、５ポイントは明瞭で容易に判読可能
×：３ポイントは殆どの文字がルーペでも判読不可、５ポイントも一部あるいは全部が目視による判読不能な状態。
（７）階調性変動
スタート時と１００万枚コピー後に、反射濃度値０．３のハーフトーン画像を形成し、その濃度変動を評価した。
【０２４８】
◎：初期と１００万枚コピー後の濃度変動が、０．３±０．０５以内
○：初期と１００万枚コピー後の濃度変動が、０．３±０．１以内
×：初期と１００万枚コピー後の濃度変動が０．３±０．１を超える。
【０２４９】
以上の結果を表３に示す。
【０２５０】
【表３】

【０２５１】
上記評価結果より明らかな様に、本発明に係る製造方法により作製されたトナーである実施例１〜１３では、高温高湿下での１００万枚に及ぶ連続コピー実施後でも帯電性変動のない非常に安定したトナーが得られ、上記環境下における画像形成でも感光体フィルミングやクリーニング不良の発生が見られなかった。さらに、１００万枚の連続コピーを行ってもカブリ発生がなく、網点再現性やライン幅、文字つぶれのない細線再現性が優れ、ハーフトーン画質の良好な画像が得られた。
【０２５２】
本発明に係る製造方法で得られたトナーは、デジタル画像形成装置に要求される細線再現性やハーフトーン画像再現性といった画質性能を１００万枚の連続コピー後も再現可能であることが確認された。
【０２５３】
なお、本発明では、本実施例実施後、更に５００万枚及び１０００万枚の連続コピーを行い、上記評価を行ったところ、いずれも良好な結果が得られることが見出された。
【０２５４】
【発明の効果】
本発明によれば、遠心沈降装置によるトナー粒子分散液の濃縮を経て得られたトナー粒子では、トナー粒子表面に不純物の残存が全く見られないことが確認され、トナー粒子表面に不純物を残存することなく、しかも、１００万枚を超える連続プリントを長期にわたり行ってもトナー粒子表面における帯電性が変動することなく、かつ、機械的に安定した強度を有するトナーが得られることを確認した。
【図面の簡単な説明】
【図１】 本発明に係るトナーの製造方法を含む流れを示す模式図である。
【図２】 本発明に使用されるディスク型遠心沈降装置内におけるトナー粒子分散液中のトナー粒子と不純物を含有する分散媒の移動を示す図である。
【図３】 本発明で使用されるディスク型遠心沈降装置の接合部の開閉による濃縮したトナー粒子分散液の自動排出を示す図である。
【図４】 分離沈降面積式における各構成の所在を示す模式図である。
【図５】 本発明で製造されるトナー粒子の粒子構造の例を示す模式図である。
【符号の説明】
１ 遠心沈降装置本体
２ 上部部材
３ ロータ
４ 下部部材
５ 濃縮室
６ 接合部
７ 下部部材操作室
１０ 沈降板
１２ 液体集積室
１５ 送入管
１７ 送出管
３０ 収集部
Ｒ トナー粒子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner manufacturing apparatus and a manufacturing method used in an electrophotographic image forming apparatus such as a printer. More specifically, the present invention relates to a toner cleaning technique that effectively removes impurities adhering to the toner particle surface.
[0002]
[Prior art]
A polymerized toner that forms toner particles through a polymerization process in an aqueous medium can control the particle size and shape of the toner particles in the manufacturing process as described in Patent Document 1, for example. A rounded toner having a sharp distribution and having no corners on the surface of the particles having the same shape of each particle can be obtained.
[0003]
When image formation is performed using toner having such a uniform size and shape, excellent fine line reproducibility and high resolution are manifested, and in particular, a minute amount of 1200 dpi (number of dots per inch, 1 inch is 2.54 cm). It is most suitable for digital image formation for forming dot images.
[0004]
The polymerized toner is obtained by producing toner particles in an aqueous medium and then separating the toner particles from the aqueous medium by a separation means represented by a solid-liquid separation device such as a filtration device. The aqueous medium in which the toner particles are dispersed contains impurities such as a surfactant, a free release agent particle desorbed from the surface of the toner particle, and a decomposition product particle thereof. Therefore, when separating the toner particles from the aqueous medium, it is necessary to clean the toner particles so that these impurities do not remain on the surface.
[0005]
For the purpose of removing impurities from the toner particle surface, Patent Document 2 discloses that toner particles are supplied by supplying washing water until the electric conductivity of the filtrate falls below a specific value while separating solid particles and an aqueous medium by centrifugation. Techniques for cleaning are disclosed. In Patent Document 3, a cleaning liquid is added to a toner particle from which an aqueous medium has been removed in a container having a stirring blade and a filtering material, and the toner particle is filtered to remove impurities under pressure. Technology is disclosed.
[0006]
However, it has been confirmed that the toner obtained through the cleaning method disclosed in Patent Document 2 and Patent Document 3 gradually changes in charging property when it is stirred for a long time in the developing device after being put into the image forming apparatus. In particular, this tendency is prominent when continuous printing of 100,000 sheets or more is performed, or when continuous image formation is performed in a low-humidity environment. It was recognized once again that it is very difficult to provide a stable toner whose chargeability does not vary over a long period of time. Recently, there is also an image forming apparatus called book-on-demand, which outputs a large amount of multi-page documents and binds them into a booklet form. Continuous printing exceeding hundreds of thousands or millions of sheets is possible. It is no longer unusual among user applications.
[0007]
As described above, the concentration of the toner particle dispersion using the existing centrifugal separator is performed in an environment in which the toner particles are easily affected by the centrifugal force, so that the concentrated toner particles are strongly influenced by the centrifugal force. It is presumed that the mechanical strength is lowered and weakened such that it is easily destroyed during image formation, or the charging performance varies due to the uniformity of the orientation of polar groups on the toner particle surface.
[0008]
[Patent Document 1]
JP 2000-214629 A
[0009]
[Patent Document 2]
JP 2000-292976 A
[0010]
[Patent Document 3]
JP 2001-249940 A
[0011]
[Problems to be solved by the invention]
  In view of the circumstances as described above, the present invention provides a variation in chargeability without disturbing the orientation of polar groups on the surface of the toner particles or degrading the mechanical strength of the toner particles when the toner particle dispersion is concentrated. Toner with excellent mechanical strength and toner that produces stable toner that does not cause photoconductor filming or cleaning failure even when continuous printing of several hundred thousand sheets or more is performed.ーAn object is to provide a manufacturing method.
[0012]
  Further, the present invention does not leave impurities such as a free release agent on the surface of the toner particles, and fog or toner scattering occurs even when continuous printing of several hundred thousand sheets or more and image formation in a low humidity environment. A toner that produces high-quality images that do not cause toner contamination and that does not cause toner contamination on the photoreceptor.ーA second object is to provide a manufacturing method.
[0013]
[Means for Solving the Problems]
As a result of repeated studies, the inventors have noted that the specific gravity of impurities adhering to the toner particles is very close to the specific gravity of water. In a centrifugal separator used for concentrating a liquid (hereinafter referred to as a toner particle dispersion) in which toner particles that have undergone particle formation are dispersed, the surface of the toner particles even if the settling distance of the toner particles is very short It has been found that impurities can be sufficiently removed from.
[0014]
  AndMultipleCentrifugal sedimentation device with a settling plate and a very short sedimentation distanceUsingThis makes it possible to instantly concentrate the toner particle dispersion and reliably remove impurities adhering to the toner particles without destroying the stable orientation of the polar groups on the toner particle surfaces.ofManufacturingMethodI found.
[0015]
As a result, even in continuous printing on several hundred thousand sheets and image formation under low humidity environment, stable image formation that does not cause photoconductor filming or cleaning failure or image failure due to toner contamination without causing fluctuation in charging property The present inventors have found a toner that can be used.
[0016]
  That is, the present invention is achieved by any one of the configurations described below.
[0022]
  [1] In aqueous mediaSalting out / fusing resin particlesA toner manufacturing method for forming toner particles and manufacturing toner through a state of toner particle dispersion,
  In the toner manufacturing method, the toner particle dispersion liquid is contained in a container that contains 0.25 mm or more.1.0Using a centrifugal sedimentation apparatus provided with a plurality of sedimentation plates that are opened downward at intervals of mm or less and arranged in a conical shape,
  A toner particle dispersion having a toner particle concentration of 8 mass% or more and 40 mass% or less is applied with a centrifugal force of 5000 G or more and 15000 G or less, and the toner particles contained in the toner particle dispersion liquid are centrifugally settled to disperse the toner particles. While concentrating the liquid,
  Automatically discharging the concentrated toner particle dispersion out of the centrifugal settling device;
A method for producing toner, wherein an automatic discharge time when the concentrated toner particle dispersion is automatically discharged out of the centrifugal sedimentation apparatus is 1 second or less per liter of the concentrated toner particle dispersion.
[0023]
  [2]The toner production method according to [1] above, wherein the toner particle dispersion or the concentrated toner particle dispersion has a pH of 2 to 6.5.
[0024]
  [3]The toner production method according to [1], wherein the toner particle dispersion or the concentrated toner particle dispersion has a pH of 8 to 12.
[0026]
  [4]The automatically discharged concentrated toner particle dispersion is diluted in an aqueous medium, the diluted toner particle dispersion is concentrated again by a centrifugal sedimentation device, and the automatic discharge of the concentrated toner particle dispersion is repeated. [1] ~[3]The method for producing a toner according to any one of the above.
[0032]
  Production of toner according to the present inventionMethodIs,waterIn the mediumIn shapeMadetonerConcentrate the toner particle dispersion containing the particles.ProcessHave
[0033]
  The present inventionOf toner particle dispersionconcentratedUsed forAs will be described later, a disk-type centrifugal sedimentation device is representative, and this has a container having a bowl-like shape formed by superposing two members. In this invention, the accommodating part in a centrifugal sedimentation apparatus is also called a main body. The toner particle dispersion liquid to be concentrated is accommodated in the bowl-shaped accommodating portion. The container is directly connected to a rotor capable of rotating at high speed, and the toner particle dispersion is concentrated by the rotation of the rotor. In the present invention, the inside of the accommodating portion is also called a concentrating chamber, and a sedimentation plate centering on the axis of the rotating shaft of the rotor is arranged in a conical shape in the concentrating chamber. Moreover, the overlapping part of the two members constituting the housing part has a joint that can be opened and closed.
[0034]
The sedimentation plate according to the present invention is a plate-like member that sediments and separates toner particles from a toner particle dispersion by the action of centrifugal force generated by the rotation of a centrifugal sedimentation device. The sedimentation plate has a shape opened downward in a conical (pedestal) shape around the axis of the rotation shaft of the rotor in the concentration chamber.
[0035]
The total sedimentation plate area according to the present invention represents the sum of the areas of all sedimentation plates arranged in the concentration chamber. In the present invention, the total sedimentation plate area is also referred to as a separation sedimentation area.
[0036]
  The present inventionUsed inThe centrifugal sedimentation device separates and settles toner particles by the action of centrifugal force from a toner particle dispersion having a toner particle concentration of 8 to 40% by mass obtained by forming particles in an aqueous medium, and Concentration is performed, and at the same time, impurities adhering to the surface of the toner particles are removed, and the concentrated toner particle dispersion can be immediately discharged out of the apparatus.
[0037]
  The present inventionSayConcentration of the toner particle dispersion is a dispersion containing toner particles formed in an aqueous medium (usually a resin liquid is dispersed to form a low-viscosity liquid. This refers to the operation of removing the water as the dispersion medium and increasing the concentration of the toner particles in the toner particle dispersion. In the present invention, the impurities adhering to the surface of the toner particles are also removed at the same time. The concentrated toner particle dispersion referred to in the present invention refers to a toner particle dispersion in which the toner particle concentration is increased by removing water from the toner particle dispersion, and is a water-containing toner particle aggregate called a wet cake. Shall also be included.
[0038]
The method for concentrating the toner particle dispersion in the present invention uses, for example, an apparatus called a disk type centrifugal sedimentation device to separate the toner particles and the aqueous medium by centrifugally sedimenting the toner particles in the toner particle dispersion, and to concentrate the toner. The particle dispersion is immediately discharged out of the apparatus. A typical example of the centrifugal sedimentation apparatus that concentrates the toner particle dispersion is a disk-type centrifugal sedimentation apparatus. As shown in FIG. 1, the disk type centrifugal sedimentation apparatus contains a toner particle dispersion and concentrates the toner particle dispersion. In the container, a plurality of disk-shaped sedimentation plates are arranged at short intervals on the rotating shaft of a rotor that applies a centrifugal force to the toner particle dispersion during concentration, and the toner particle dispersion is concentrated with this device. It has been found that the objects of the present invention are achieved.
[0039]
In the present invention, the disk-type centrifugal sedimentation device used for concentrating the toner particle dispersion continuously concentrates a large amount of toner particle dispersion, which could only be handled by batch processing in the prior art, and the concentrated toner particle dispersion It is possible to immediately discharge out of the apparatus. That is, a centrifugal force of 5000 to 15000 G is applied to the toner particle dispersion charged in the apparatus to complete concentration instantly, and the concentrated toner particle dispersion is automatically discharged out of the apparatus continuously.
[0040]
In this way, unlike the conventional centrifugal sedimentation device, the disk-type centrifugal sedimentation device used in the present invention immediately discharges the concentrated toner particle dispersion liquid outside the device without leaving the centrifugal force acting for a long time. This solves the problem that the uniformity of the charging property on the surface of the toner particles is disturbed and the mechanical strength of the toner particles is lowered.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
  The present inventionsoThe disk-type centrifugal sedimentation device used concentrates the toner particle dispersion by instantaneously sedimenting the toner particles in the toner particle dispersion by the action of centrifugal force, and at the same time, the concentrated toner particle dispersion is placed outside the device. Quick and automatic discharge.
[0042]
As described above, the present invention has been found by paying attention to the specific gravity difference between the toner particles and the impurities in the toner particle dispersion. That is, the present inventor noticed that the specific gravity of impurities such as a free release agent remaining on the particle surface is not so different from the specific gravity of water. It was speculated that impurities could be reliably removed from the toner particle surface even if the distance was significantly shortened, and the present invention was reached.
[0043]
  FIG. 1 shows the production of toner according to the present invention.Including methodsFlowThisIt is a schematic diagram shown. In the present invention, the toner particle dispersion is concentrated using the disk-type centrifugal sedimentation apparatus shown in FIG. 1, and FIG. 1 shows a cross-sectional view of the apparatus main body viewed from the axial direction. FIG.In, Particle formation process in aqueous medium, concentration process by disk type centrifugal settling device, treatment process by acid or alkali, dehydration process by centrifuge, and drying processShown.
[0045]
  The present inventionManufactured inFirst, toner particles are formed in a particle forming step in an aqueous medium. The formed toner particles are dispersed in an aqueous medium to form a toner particle dispersion. Subsequently, the toner particle dispersion is concentrated using the disk-type centrifugal sedimentation apparatus 1.
[0046]
The toner particle dispersion liquid concentrated by the disk-type centrifugal sedimentation device 1 is discharged out of the device 1 and collected by the collecting unit 30. In the present invention, it has been confirmed that the toner obtained by subjecting the concentrated toner particle dispersion collected in the collecting unit 30 to acid treatment or alkali treatment tends to make its chargeability difficult to change. Specifically, the toner particle dispersion liquid concentrated using an acid such as hydrochloric acid is subjected to an acid treatment in a pH range of 2 to 6.5. Alternatively, there is a method in which a toner particle dispersion liquid concentrated with an alkali such as a sodium hydroxide solution is subjected to an alkali treatment within a pH range of 8-12.
[0047]
In the present invention, it has been confirmed that an acid treatment is performed on the concentrated toner particle dispersion to obtain a toner that is less susceptible to fluctuations in chargeability.
[0048]
The concentrated toner particle dispersion subjected to the acid or alkali treatment is finally dehydrated to a toner particle aggregate in a more concentrated state called a wet cake (in the present invention, a toner particle aggregate formed into a wet cake is also included). Into the category of concentrated toner particle dispersions). As the centrifuge used in the dehydration process for producing the wet cake, in addition to the centrifuge settling apparatus used for the concentration described above, for example, a centrifuge disclosed in Patent Document 2 or Patent Document 3 is used. It may be dehydrated.
[0049]
The toner in a wet cake state is completed through a drying process.
Next, a centrifugal sedimentation apparatus used in the concentration step in the toner production method according to the present invention will be described. The centrifugal sedimentation apparatus main body 1 has a rotor 3 at the center thereof, and is integrally coupled to the rotor and 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 the inside thereof has a concentration chamber 5 in which a settling plate 10 described later is disposed. In addition, the toner particle dispersion concentrated in the concentration chamber 5 is automatically discharged from the joint 6 between the upper member 2 and the lower member 4 to the outside of the apparatus.
[0050]
The disk-type centrifugal sedimentation apparatus used in the present invention can separate solid particles if the particle specific gravity difference is 2% or more. With the specific gravity difference between the toner particles and impurities according to the present invention, an extremely short sedimentation distance can be obtained. Particles and impurities can be removed.
[0051]
As shown in FIG. 1, the disk-type centrifugal sedimentation apparatus used in the present invention has a shape in which a conical sedimentation plate 10 is overlapped around a rotor at the center of the apparatus with umbrellas being overlapped at intervals of 0.5 to 1 mm. It is arranged. That is, in the present invention, since the specific gravity of the impurities adhering to the toner particle surface has a value substantially equal to the specific gravity of water, the impurities from the toner particle surface can be obtained even if the settling plate is arranged with a very short settling distance. It is possible to obtain a concentrated toner particle dispersion by removing the water reliably. The centrifugal sedimentation apparatus used in the present invention can reliably remove impurities if the specific gravity difference between the toner particles and the impurities is 2% or more. It is also possible to change the sedimentation distance according to the amount of toner particle dispersion to be concentrated.
[0052]
The disk-type centrifugal sedimentation device used in the present invention converts the natural sedimentation due to gravity into a force exceeding 5000 to 15000 times by centrifugal force, that is, the surface of the toner particle by the action of centrifugal force having a size of 5000 to 15000G. Impurities are removed from the toner particles, and a concentrated toner particle dispersion is obtained.
[0053]
The processing performance of the disk-type centrifugal sedimentation device used in the present invention has the performance of completing the concentration of 1 liter of toner particle dispersion in less than 1 second. Further, in the disk-type centrifugal sedimentation apparatus used in the present invention, the concentrated toner particle dispersion liquid from which impurities are removed is automatically discharged from the joint portion 6, so that the toner particle dispersion liquid is concentrated and simultaneously concentrated. The toner particle dispersion can be automatically discharged out of the concentration chamber 5. Therefore, productivity and work efficiency in the toner particle dispersion concentration process are greatly improved.
[0054]
Further, since the concentrated toner particle dispersion is immediately discharged out of the disk-type centrifugal sedimentation device used in the present invention, the concentrated toner particle dispersion is discharged for a long time in an environment where a large centrifugal force of 5000 to 15000 G acts. No load is applied to the toner particles due to the influence of centrifugal force. As a result, there is no problem of occurrence of orientation disorder of polar groups on the surface of the toner particles and a decrease in strength of the toner particles, so that a toner having excellent charging performance and mechanical strength can be obtained.
[0055]
Further, the interval between the settling plates of the disc type centrifugal settling device used in the present invention is 0.5 mm or more, but the specific gravity difference between toner particles and water is about 0.1 even at such a short interval. The toner particle dispersion can be concentrated and impurities can be removed. It has been confirmed that the interval between the settling plates, which is the settling distance of the particles, is preferably 0.5 mm to 10 mm, and more preferably 0.75 mm to 1 mm.
[0056]
In the present invention, since the toner particle dispersion liquid can be concentrated and impurities can be removed by allowing the toner particles to settle at a short distance as described above, it is not necessary to use a filter medium during concentration.
[0057]
In the disc type centrifugal sedimentation apparatus used in the present invention, the sedimentation plate is arranged in a conical shape around the rotation axis as described above, but a thin plate-shaped sedimentation plate 10 is conical as shown in FIG. It is arranged in a form that is opened downward so as to be stacked in an inclined state, and as if it is stacked as if the umbrellas are opened, separation is more than 10 times the installation area of the centrifugal sedimentation device It is possible to obtain a sedimentation area, enabling large-scale and high-speed separation at the same time as improving work space efficiency. In the present invention, it has been confirmed that a separation and sedimentation area 10 times or more than the installation area of the concentration means can be obtained.
[0058]
In the concentration of the toner particle dispersion by the disk type centrifugal sedimentation apparatus used in the present invention, the solid content volume ratio (hereinafter also referred to as toner particle concentration) in the toner particle dispersion to be concentrated is 2 to 85%, preferably It is 5 to 60%, more preferably 8 to 40%. Moreover, the particle size should just be 0.1 micrometer or more. The toner particle concentration of the toner particle dispersion liquid to be concentrated is, for example, not only the concentration of the toner particle dispersion liquid immediately after completion of the formation of the toner particles in the aqueous medium but also automatically concentrated outside the centrifugal sedimentation device. The concentration of the toner particle dispersion obtained by collecting the discharged concentrated toner particle dispersion and putting it into washing water is also included.
[0059]
For comparison, the conventional centrifugal sedimentation apparatus and the decanter system preferably have a solid content volume ratio of 5 to 60% and a particle size of 10 μm or more, so that 10 μm like the toner particles obtained by the polymerization method. It was very difficult to remove impurities from the surface of the toner particles having a small particle size of less than 1.
[0060]
Thus, in the present invention, from the surface of the toner particles having a volume average particle diameter of 3 to 9 μm obtained by forming particles in an aqueous medium, which has been difficult in the past, using a disk-type centrifugal sedimentation apparatus having the above-described performance. Improve impurity removal dramatically.
[0061]
In the disk-type centrifugal sedimentation apparatus 1 used in the present invention, a settling plate made of a thin plate for concentrating a toner particle dispersion is arranged in an inclined state with a plurality of layers being stacked at a short interval of 0.5 to 1 mm. Concentration of a large amount of toner particle dispersion containing toner particles that have completed particle formation in the medium and operations for removing impurities from the toner particle surface are performed continuously and rapidly.
[0062]
Next, concentration of the toner particle dispersion by the disk type centrifugal sedimentation apparatus preferably used in the present invention will be described. FIG. 2 is a diagram illustrating movement of a dispersion medium (aqueous medium) containing toner particles and impurities in the toner particle dispersion in the apparatus main body shown in FIG. The black circles in the figure indicate the toner particles R, the solid arrows in the figure indicate the flow of the toner particle dispersion before concentration, the white arrows indicate the movement of the toner particles, and the broken arrows indicate the removal of the toner particles after concentration. The flow of the liquid was shown. In FIG. 2, the illustration of the impurity particles is omitted.
[0063]
When a centrifugal force of 5000 to 15000 G acts in the disk-type centrifugal sedimentation apparatus preferably used in the present invention, the toner particles R move in the centrifugal force direction in the upper part between the sedimentation plates 10 and are accumulated at the periphery of the concentration chamber 5. The At this time, impurities such as free mold release agent adhering to the surface of the toner particles are removed from the surface of the toner particles so that the rice cake and the rice flour attached to the surface of the rice are scraped off when the rice is cooked during cooking. Removed.
[0064]
Then, the liquid containing the impurities from which the toner particles R are removed moves to the center of the apparatus through the lower part between the settling plates 10. Since the specific gravity of the impurities composed of the free release agent and the like is almost the same as the specific gravity of the dispersion, it moves to the center of the apparatus together with the dispersion. In this way, the toner particle dispersion is concentrated and the impurities are desorbed from the toner particle surface.
[0065]
Further, the concentrated toner particle dispersion accumulated in the periphery of the concentration chamber 5 is about several millimeters at the junction 6 at the boundary between the upper member 2 and the lower member 4 constituting the apparatus main body 1 as shown in FIG. When it is opened, it is automatically discharged out of the concentration chamber 5 instantly. In this way, the concentrated toner particle dispersion is automatically discharged to the outside of the main body of the apparatus. Therefore, a filter medium is used as in the prior art to discharge the concentrated toner particle dispersion outside the centrifugal sedimentation apparatus. There is no need to do.
[0066]
In the disk-type centrifugal sedimentation apparatus preferably used in the present invention, the toner particle dispersion liquid in which the particles are formed in an aqueous medium is continuously passed through the apparatus, while concentrating and removing impurities from the toner particle surface. Furthermore, the operation of automatically discharging the toner particle dispersion concentrated by the action of centrifugal force to the outside of the concentration chamber 5 can be continuously performed. In the disk-type centrifugal sedimentation apparatus preferably used in the present invention, the concentrated slurry automatically discharged from the concentration chamber 5 is collected in a storage space (not shown) in the outer peripheral portion of the apparatus body 1 and collected using a filter medium or the like. It is preferable in terms of production efficiency.
[0067]
Opening and closing of the joint portion 6 of the disc type centrifugal sedimentation device main body 1 preferably used in the present invention is achieved by the vertical movement of the lower member 4 constituting the device main body 1. 3A and 3B are schematic views showing opening and closing of the joint portion 6 of the apparatus main body 1. FIG. 3A shows the non-discharge state when the joint portion 6 is closed, and FIG. 3B shows the joint portion 6 being opened. Indicates automatic discharge. In the figure, the solid arrow indicates the flow of the toner particle dispersion before concentration, the white arrow indicates the movement of the toner particles, and the broken arrow indicates the flow of the liquid not containing the toner particles after concentration. Furthermore, hatched arrows indicate the moving direction of the lower member 4.
[0068]
The lower member 4 is moved up and down by filling high pressure water into a lower member operation chamber (also referred to as a sealing chamber) shown in 7 of FIG. 1, and strongly lowering the lower member 4 against the upper member 2 as shown in FIG. A closed state of the joint portion 6 is formed by forming a pressed state and forming a close contact state therebetween. Further, when the high pressure water filled in the lower member operation chamber is removed, the lower member 4 is lowered and the joint portion 6 is opened. When opened, a gap of about several millimeters is formed between the lower member 4 and the upper member 2, and the concentrated toner particle dispersion accumulated on the peripheral surface of the concentration chamber 5 by the centrifugal force generated by the rotation of the rotor 3 is instantaneously generated. It is discharged out of the concentration chamber 5. Thus, the opening time can be shortened by utilizing the centrifugal force generated by the rotation of the rotor 3 when the joint 6 is opened.
[0069]
Control of opening / closing of the joint 6 is achieved by receiving a signal from a sensing device (not shown) such as a timer trigger or a self-trigger and controlling supply and discharge of high-pressure water to the lower member operation chamber 7. When the concentrated toner particle dispersion is constantly generated, the sensing device that controls the opening and closing of the joint 6 has a predetermined time because the accumulation rate of the concentrated toner particle dispersion in the concentration chamber 5 is substantially constant. It is preferable to control opening and closing by a timer trigger that automatically discharges at intervals.
[0070]
Further, when there is variation in the amount of concentrated toner particle dispersion accumulated per unit time, the concentration rate of the concentrated toner particle dispersion in the concentration chamber 5 is not constant. Opening / closing control by a self-trigger that controls the joint 6 to be opened when the accumulated amount of the toner particle dispersion reaches a predetermined amount is preferable. The automatic discharge control means of the centrifugal sedimentation device used in the present invention may be a control method other than the above.
[0071]
In this way, impurities are removed by opening the joint 6 at the boundary between the upper member 2 and the lower member 4 which is an automatic discharging means for the concentrated toner particle dispersion of the disk type centrifugal sedimentation apparatus preferably used in the present invention. The concentrated toner particle dispersion liquid is discharged out of the concentration chamber 5 at a high speed. Further, since the opening gap of the joint 6 is set to several millimeters and is closed in a short time, an impact associated with opening and closing is not generated as much as possible. In addition, since the amount of high-pressure water used for opening and closing is minimized, energy and resource saving measures are also considered.
[0072]
The opening / closing frequency of the joint 6 of the disk-type centrifugal sedimentation apparatus preferably used in the present invention is not particularly limited because the impact at the time of discharge does not impose a burden on the apparatus as described above. However, there is no problem in carrying out automatic discharge up to about 60 times per hour from the viewpoint of work efficiency and production efficiency.
[0073]
The collection performance of the concentrated toner particle dispersion per hour of the centrifugal sedimentation apparatus preferably used in the present invention is, for example, 70% of the set capacity in the solid content storage space for storing the discharged toner particle dispersion. When the particle dispersion is collected when it is stored, it is expressed by the following equation.
[0074]
Recovery performance of concentrated toner particle dispersion per hour
= Storage space x 0.7 x 60
Further, in the disk-type centrifugal sedimentation apparatus preferably used in the present invention, the toner particle dispersion can be continuously concentrated, so that the amount of the concentrated toner particle dispersion that is automatically discharged from the joint 6 each time is constant. Thus, a toner particle dispersion in which the toner particles in the concentrated toner particle dispersion have a constant quality can be obtained.
[0075]
The disk-type centrifugal sedimentation device used in the present invention instantaneously concentrates the toner particle dispersion with a centrifugal force of 5000 to 15000 G, and automatically discharges the concentrated toner particle dispersion. Since the opening is frequently performed, the concentrated toner particle dispersion is not retained in the concentration chamber 5 for a long time. Therefore, since the toner particles in the concentrated toner particle dispersion are not significantly affected by the centrifugal force, the orientation of the polar groups is not disturbed on the surface of the toner particles, so that the obtained toner has a uniform charge distribution. . Further, since there is little possibility of deterioration due to mechanical action due to centrifugal force, mechanically stable and robust toner particles can be obtained.
[0076]
Further, since the concentrated toner particle dispersion is reliably discharged from the concentration chamber 5 to the outside of the apparatus, the concentrated toner particle dispersion does not remain in the concentration chamber 5. Therefore, it is possible to easily clean the inside of the concentrating chamber 5 or to disassemble the concentrating chamber during periodic inspection of the apparatus, so that the maintenance performance of the apparatus is greatly improved.
[0077]
Next, the separation and sedimentation area of the sedimentation plate which is the sedimentation means of the disc type centrifugal sedimentation apparatus used in the present invention will be described.
[0078]
It is known among the experts of the centrifugal sedimentation apparatus that the performance of the disk type centrifugal sedimentation apparatus used in the present invention is indicated by the separation sedimentation area Σ represented by the following formula. Although described as “separation”, the term “separation” is used because the toner particles formed during the concentration of the toner particle dispersion liquid are solid-liquid separated from the dispersion medium by centrifugal force.
[0079]
Separation sedimentation area Σ = 2.34 × 10^-3× n²× N × cot α × (r₁ ^Three-R₂ ^Three)
In the above formula,
N: number of sedimentation plates, n: number of rotations (rpm), r₁: Outer diameter of sedimentation plate
r₂: Inner diameter of settling plate, α: Half apex angle of settling plate
Represents.
[0080]
FIG. 4 is a schematic diagram showing the location of each component in the separated sedimentation area formula. The half apex angle of the sedimentation plate indicates the degree of inclination of the sedimentation plate and, as is apparent from FIG. 4, represents the inclination angle of the sedimentation plate with respect to the vertical direction.
[0081]
As is clear from the above equation, the centrifugal sedimentation apparatus used in the present invention is not only the centrifugal force but also the performance of the sedimentation plate is an important factor in achieving effective removal of impurities from the surface of the formed particles. ing.
[0082]
In addition, recent progress in centrifugal sedimentation technology is surprising, and it has been found that the value of the above-mentioned separation sedimentation area Σ deviates from the actual centrifugal sedimentation performance, and the centrifugal sedimentation capacity index KQ represented by the following formula It is said that the value of is the best reflection of the performance of the actual centrifugal sedimentation apparatus among experts related to the centrifugal sedimentation apparatus.
[0083]
Centrifugal function index KQ
= 280 × (n / 1000)^1.5× N × cot α × (r₁ ^2.75-R₂ ^2.75)
The rotation speed n of the disk-type centrifugal sedimentation apparatus used in the present invention is 100 to 10,000 rpm, more preferably 500 to 5000 rpm, and particularly preferably 2000 to 4500 rpm. Further, the number N of settling plates arranged in the apparatus, the outer diameter r of the settling plate₁, Inner diameter r of settling plate₂Is set so as to obtain the maximum separation and sedimentation area according to the installation environment of the apparatus. By appropriately setting these values, the installation area of the concentration means is 10 times or more as described above. Since it is possible to obtain a separation and sedimentation area, a large amount of toner particle dispersion can be concentrated in a short time even with a small concentration means having a small installation area.
[0084]
As described above, the disk-type centrifugal sedimentation device used in the present invention is basically the conventional centrifugal sedimentation device by arranging the conical thin plates so as to have an extremely short sedimentation distance as described above. It was possible to obtain a very large separation sedimentation area that could not be achieved. As a result, it is possible to remove impurities from the toner particle surface in a large amount of toner particle dispersion in a very short time, and at the same time, it is possible to concentrate the toner particle dispersion.
[0085]
In addition, when concentrating the toner particle dispersion, the concentrated toner particle dispersion is discharged without using a filter medium, and the amount of washing water used is reduced and the device is made compact. Therefore, it is possible to manufacture toner that supports energy saving and resource saving, such as reduction of power consumption and prevention of waste generation due to work.
[0086]
Next, the description of the above description will be supplemented with reference to FIG. 1 for the disk type centrifugal sedimentation apparatus preferably used in the present invention.
[0087]
The rotor 3 constituting the main body 1 of the centrifugal sedimentation apparatus preferably used in the present invention is combined with the upper member 2 by a tightening ring 30 to form an integral structure. Further, it is confirmed that the lower member 4 is integrally formed with the rotor 3.
[0088]
The upper member 2 and the lower member 4 constituting the main body 1 have a shape such that the bowls are overlapped and form a joint portion 6 that can be opened and closed, but the outer diameter of the lower member 4 at the joint portion is joined. A slightly larger outer diameter of the upper member 2 in the portion is preferable in order to ensure the sealing performance in the concentration chamber 5 as the housing portion.
[0089]
As described above, reference numeral 7 denotes a lower member operation chamber, in which high pressure water is charged and discharged to move the lower member 4 up and down to open and close the joint 6. The lower member operation chamber 7 includes an inlet 8 and an outlet 9 for high-pressure water.
[0090]
In the concentrating chamber 5, a sedimentation plate (also referred to as a disc stack) rotor 3 composed of a plurality of conical separation discs is arranged around the rotation axis. 11 is a distributor. As shown in FIG. 1, a liquid accumulation chamber 12 is disposed at the upper end of the upper member, and a dispersion containing impurities from which toner particles have been separated is directed from the concentration chamber 5 to the liquid accumulation chamber 12 via a passage 13. It is possible to send liquid.
[0091]
During operation of the rotor 3, the liquid collected in the liquid accumulation chamber 12 forms a rotating liquid having a free liquid surface 14 on the radially inner side.
[0092]
A pipe extending through the liquid accumulation chamber 12 and extending to the center is a feed pipe 15, which is a pipe for introducing the toner particle dispersion into the concentration chamber 5. The feed pipe 15 opens into a feed chamber 16 inside the distributor 11. A fixed delivery pipe 17 above the delivery pipe 15 is arranged for separating a liquid having a low specific gravity in the dispersion collected in the liquid accumulation chamber 12. In addition, a delivery device 18 is disposed in the liquid accumulation chamber 12 around the delivery pipe 15 and is connected to the delivery pipe 17. Although the delivery device 18 is fixed, it is also possible to arrange a similar delivery device to rotate at a speed lower than the rotational speed of the rotor in the heat delivery structure.
[0093]
The delivery device 18 extends radially outward within the liquid accumulation chamber 12 and has a portion located outside the radial level of the free liquid level 14. At least one delivery path 20 is arranged in the delivery device 18 together with an inlet, which is located in this part and constitutes an outlet from the liquid accumulation chamber 12. The delivery path 20 is connected to the inside of the delivery pipe 17.
[0094]
As shown in FIG. 2, the passage 13 is disposed in the center of the concentration chamber 5. In the liquid accumulation chamber 12, several wall elements are arranged around the rotation axis, and the separated liquid in the liquid accumulation chamber 12 is entrained during the operation leading to the rotation of the rotor 3, and radially outward. In order to guide this towards the outlet, a flow path is formed between these elements. In this case, at least a part of the wall element extends radially between the radial level where the free liquid level is located and the level radially outward of the outlet.
[0095]
Next, the concentration step in the centrifugal sedimentation apparatus used in the present invention will be described with reference to FIG.
[0096]
When the centrifugal sedimentation apparatus is started, the rotor 3 rotates, and high pressure water is supplied from the inlet 8 to the lower member operation chamber 7, so that the joint between the upper member 2 and the lower member 4 is tightly adhered, and the concentration chamber 5 is sealed. Is done. When the concentrating chamber 5 is sealed, the toner particle dispersion is supplied into the concentrating chamber 5 from the inflow tube 15 through the inflow chamber 16. By the time the concentration chamber 5 is filled with the toner particle dispersion, the rotor 3 obtains the operating rotational speed and stabilizes the conditions in the concentration chamber 5. Centrifugal force is applied to the supplied toner particle dispersion to concentrate the toner particle dispersion and remove impurities from the toner particle surface.
[0097]
Concentration of the toner particle dispersion and removal of impurities from the toner particle surface are performed mainly in a space formed between the conical settling plates 10. Toner particles having a large specific gravity in the toner particle dispersion move outward in the radial direction by the action of centrifugal force and accumulate in the radially outermost region of the concentration chamber 5.
[0098]
In addition, impurities and dispersion having a light specific gravity in the toner particle dispersion flow in the radially innermost region of the concentration chamber 5.
[0099]
When the lower member 4 is lowered after a predetermined time and the peripheral joint 6 is opened for several millimeters, the concentrated toner particle dispersion is vigorously discharged out of the concentration chamber 5 by the action of centrifugal force. Further, the liquid component containing no impurities and containing impurities passes through the passage 13 from the concentration chamber 5 and is concentrated in the liquid accumulation chamber 12 to form a rotating liquid having a free liquid surface directed radially inward. The liquid in the liquid accumulation chamber 12 passes through the outlet and is discharged out of the passage device through the delivery path 20 in the delivery device 18 that is fixed.
[0100]
Entrainment of the liquid component in the liquid accumulation chamber 12 is made by the wall element rotating together with the rotor 3 and the defining surface of the liquid accumulation chamber 12.
[0101]
The liquid closest to the delivery device 18 is reduced in speed by contacting the outlet face of the delivery device 18. Different parts of the liquid in the liquid accumulation chamber 12 will thus obtain different rotational speeds. A liquid flow that circulates in the liquid accumulation chamber 12 due to contact between the liquid and the outer surface of the delivery device 18, and as described above, the liquid flows radially inward along the outer surface of the delivery device 18 and viewed from the rotational direction. And flow radially outward along the rear wall element of the two wall elements forming the flow path.
[0102]
In this way, the toner particle dispersion containing the toner particles formed in the aqueous medium is concentrated by the disk-type centrifugal sedimentation apparatus preferably used in the present invention, and at the same time, impurities are removed from the toner particle surfaces. Further, the concentrated toner particle dispersion can be discharged out of the centrifugal sedimentation device without using a filter medium.
[0103]
In the present invention, the concentrated toner particle dispersion may be dispersed again in the cleaning liquid to thoroughly wash the toner particles, and then the toner particle dispersion may be repeatedly concentrated. In the present invention, the total amount of washing water for redispersing the toner particles in the concentrated toner particle dispersion is within a range of 5 to 10 times that of the toner particle dispersion charged in the initial concentration. It was confirmed that a chargeable toner was obtained. It was confirmed that the chargeability of the toner obtained by washing with the amount of water in the above range does not fluctuate even when continuous printing exceeding 3 million sheets is performed.
[0104]
Next, toner particles obtained by the production method according to the present invention will be described. According to the production method of the present invention, for example, as shown in FIG. 5, the resin constituting the particles and the components of the crystalline substance and the colorant that are the release agent components are not mixed with each other. It is also possible to obtain toner particles having a sea-island structure that forms phases independently. The toner particles shown in FIG. 5 have a structure in which islands A of a crystalline substance constituting a release agent and islands B of a colorant component are present in a continuous phase (sea) of a resin. As a means for confirming the structure of the toner particles obtained in the present invention, a cross-sectional photograph taken with a transmission electron microscope shows that the sea region and the island region have different brightness areas in the toner particles. Confirmed by
[0105]
  next,The present inventionManufactured inThe particle diameter of the toner will be described. The present inventionManufactured inThe toner has a volume average particle diameter of 3 to 9 μm, preferably 3.5 to 8 μm, and more preferably 3.5 to 7.5 μm. In the toner particle production method, the particle size can be controlled by the concentration of the flocculant (salting-out agent), the amount of organic solvent added, the fusing time, and the polymer composition.
[0106]
When the volume average particle diameter is 3 to 9 μm, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved. Calculation of the particle size distribution of the toner and measurement of the volume average particle size are performed using a Coulter Counter TA-II, Coulter Multisizer (both manufactured by Coulter), SLAD1100 (Laser diffraction type particle size measuring device manufactured by Shimadzu Corporation) and the like. Can be measured. In the present invention, a Coulter Multisizer is used to measure and calculate an interface (manufactured by Nikkaki Co., Ltd.) that outputs a particle size distribution and a personal computer.
[0107]
  Next, a toner manufacturing method according to the present invention will be described.
  The present inventionManufactured inThe toner is obtained through a process of aggregating resin particles in an aqueous medium to form toner particles. That is, a polymerizable monomer is polymerized in an aqueous medium, and the obtained polymer is aggregated to obtain toner particles.
[0108]
A typical method for producing the toner according to the present invention includes a method in which resin particles are prepared by salting out / fusion in an aqueous medium. Here, the “aqueous medium” refers to a medium containing at least 50% by mass of water. This method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904.
[0109]
That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, or a constituent material such as resin particles and a colorant, and in particular using an emulsifier in water Then, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer is heated and fused at a temperature higher than the glass transition temperature of the polymer itself to gradually grow the particle size while forming fused particles. When the desired particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluidized state while containing water. By drying, toner particles for private use in the present invention can be formed. Here, a solvent that is infinitely soluble in water, such as alcohol, may be added simultaneously with the flocculant.
[0110]
In the method for producing a toner according to the present invention, composite resin fine particles and colorant particles formed through a step of polymerizing a polymerizable monomer after dissolving a functional substance such as a release agent in at least the polymerizable monomer Is salted out / fused to obtain toner particles. The toner according to the present invention dissolves a functional substance such as a release agent in a polymerizable monomer, but it may be dissolved and dissolved or melted and dissolved.
[0111]
In addition, the toner production method according to the present invention is preferably one in which composite resin fine particles obtained by a multistage polymerization method and colorant particles are salted out / fused. Hereinafter, the multistage polymerization method will be described.
[0112]
The multistage polymerization method is a method in which a polymerization reaction is performed in multiple stages in order to form phases having different molecular weight distributions in one resin particle. The obtained resin particles are directed from the center of the particle toward the surface layer. This is intended to form a molecular weight gradient. For example, a method of forming a low molecular weight surface layer by first obtaining a high molecular weight resin particle dispersion and then newly adding a polymerizable monomer and a chain transfer agent is employed.
[0113]
<Two-stage polymerization method>
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin and an outer layer (shell) formed from a low molecular weight resin.
[0114]
This method will be described in detail. First, the monomer solution is dispersed in oil droplets in an aqueous medium (for example, an aqueous surfactant solution), and then this system is polymerized (first stage polymerization). A dispersion of high molecular weight resin particles is prepared.
[0115]
Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the dispersion of the resin particles, and the monomer is polymerized in the presence of the resin particles (second-stage polymerization). Thus, a coating layer made of a low molecular weight resin (monomer polymer) is formed on the surface of the resin particles. Here, a functional substance such as a release agent may be added to the high molecular weight component serving as the core of the central portion.
[0116]
<Three-stage polymerization method>
The three-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin, an intermediate layer, and an outer layer (shell) formed from a low molecular weight resin.
[0117]
This method will be specifically described. First, a dispersion of resin particles obtained by a polymerization process (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). After the monomer solution is dispersed in oil droplets in the aqueous medium, the system is polymerized (second-stage polymerization) to form a coating layer (intermediate layer) made of resin on the surface of the resin particles (core particles). ) To prepare a dispersion of composite resin particles (high molecular weight resin-intermediate molecular weight resin).
[0118]
Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the obtained dispersion of composite resin particles, and the monomer is polymerized in the presence of the composite resin particles (third-stage polymerization). ), A coating layer made of a low molecular weight resin (monomer polymer) is formed on the surface of the composite resin particles. In the above method, it is preferable that a functional substance such as a release agent is contained in the intermediate layer because it becomes possible to make the dispersion of the release agent fine and uniform.
[0119]
The aqueous medium as used in the field of this invention means the medium which consists of 50-100 mass% of water and 0-50 mass% of water-soluble organic solvents. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, and an alcohol-based organic solvent that does not dissolve the obtained resin is preferable.
[0120]
As a suitable polymerization method for forming resin particles or a coating layer containing a functional substance such as a release agent, an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved, A monomer solution in which a release agent is dissolved in a monomer is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the obtained dispersion. A method of radical polymerization in oil droplets (hereinafter referred to as “mini-emulsion method” in the present invention) can be mentioned, and the effects of the present invention can be further exhibited, which is preferable. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.
[0121]
According to the mini-emulsion method that mechanically forms oil droplets, unlike ordinary emulsion polymerization methods, functional substances such as release agents dissolved in the oil phase are less likely to be detached, and resin particles or coating layers are not separated. It is possible to introduce a sufficient amount of a functional substance such as a release agent.
[0122]
Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, the stirring device “CLEARMIX” (M technique (M Co., Ltd.), ultrasonic disperser, mechanical homogenizer, manton gorin, pressure homogenizer, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 50 to 1000 nm, and more preferably 30 to 300 nm.
[0123]
The particle diameter of the composite resin particles obtained in this polymerization step is in the range of 10 to 1000 nm in terms of mass average particle diameter measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). Is preferred.
[0124]
The glass transition temperature (Tg) of the resin particles is preferably in the range of 48 to 74 ° C, more preferably 52 to 64 ° C.
[0125]
  The softening point of the resin particles is preferably in the range of 95 to 140 ° C.
  The present inventionManufactured inThe toner is obtained by forming a resin layer formed by fusing resin particles on the surface of the resin and colored particles by a salting-out / fusing method. This will be described below.
[0126]
  [Colorant fine particles]
  The present inventionManufactured inThe colorant fine particles used for obtaining the toner are formed using a dispersing device for finely dispersing the colorant fine particles in an aqueous medium containing a surfactant.
[0127]
Here, the surfactant contained in the aqueous medium in which the colorant fine particles are dispersed is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC), and the surfactant used is used in the polymerization step. The same one can be used.
[0128]
The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but preferably a stirring device “CLEARMIX” (manufactured by M Technique Co., Ltd.) equipped with a rotor that rotates at high speed, ultrasonic dispersion And pressure dispersers such as a mechanical homogenizer, manton gourin, and pressure homogenizer, and medium dispersers such as a Getzman mill and a diamond fine mill.
[0129]
[Salting out / fusion process]
This salting-out / fusion process is carried out by salting out / bonding the resin particles and the colorant particles obtained by dispersing as described above (to cause salting-out and fusion at the same time). This is a step of obtaining (non-spherical) toner particles.
[0130]
In the present invention, salting out / fusion means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur simultaneously, or act of causing salting out and fusion at the same time. . In order to perform salting-out and fusion at the same time, it is necessary to agglomerate particles (resin particles, colorant particles) under a temperature condition equal to or higher than the glass transition temperature (Tg) of the resin constituting the resin particles.
[0131]
In this salting-out / fusion step, resin particles and colorant particles, as well as internal additive particles such as charge control agents (fine particles having a number average primary particle size of about 10 to 1000 nm) may be salted out / fused. . The colorant particles may be surface-modified, and conventionally known ones can be used as the surface modifier.
[0132]
In order to salt out / fuse the resin particles and the colorant particles, a salting-out agent (flocculating agent) having a critical aggregation concentration or more is added to the dispersion in which the resin particles and the colorant particles are dispersed. It is necessary to heat this dispersion to a temperature higher than the glass transition temperature (Tg) of the resin particles.
[0133]
The temperature range suitable for salting out / fusion is (Tg + 10) to (Tg + 50 ° C.), and particularly preferably (Tg + 15) to (Tg + 40 ° C.). In addition, an organic solvent that is infinitely soluble in water may be added in order to effectively perform fusion.
[0134]
In the present invention, resin particles and a colorant are salted out, aggregated, and fused in an aqueous medium to obtain colored particles (referred to as toner particles in the present invention), and then the toner particles are separated from the aqueous medium. Sometimes, it is preferably performed at a temperature higher than the Kraft point of the surfactant present in the aqueous medium, and more preferably in the temperature range of Kraft point to (Craft point + 20 ° C.).
[0135]
The Kraft point is a temperature at which an aqueous solution containing a surfactant starts to become cloudy, and the Kraft point is measured as follows.
[0136]
<Measurement of craft point>
A solution was prepared by adding the actual amount of the flocculant to the aqueous medium, that is, the surfactant solution used in the salting out, agglomeration and fusion processes, and this solution was stored at 1 ° C. for 5 days. The solution was then gradually heated with stirring until clear. The temperature at which the solution becomes clear is defined as the Kraft point.
[0137]
  The present inventionManufactured inThe toner preferably contains 350 ppm to 35000 ppm, more preferably 500 ppm to 30000 ppm, of the metal element described above (including metal, metal ion, etc.).
[0138]
The residual amount of metal ions in the toner is measured using a fluorescent X-ray analyzer “System 3270 type” (manufactured by Rigaku Denki Kogyo Co., Ltd.), and the metal species of the metal salt used as a flocculant (for example, calcium chloride It can be determined by measuring the intensity of the fluorescent X-ray emitted from the derived calcium or the like. As a specific measurement method, a plurality of toners having a known content ratio of the flocculant metal salt are prepared, each toner 5g is pelletized, the content ratio (mass ppm) of the flocculant metal salt, and the metal species of the metal salt The relationship (calibration curve) with the fluorescent X-ray intensity (peak intensity) is measured. Next, the toner (sample) whose content of the flocculant metal salt is to be measured is similarly pelletized, and the fluorescent X-ray intensity from the metal species of the flocculant metal salt is measured. Amount "can be determined.
[0139]
  The present inventionManufactured inIn the toner, it is preferable to use a polymer dispersant instead of the surfactant in order to leave a large amount of salt, or to control the residual amount of salt by using a surfactant and a polymer dispersant in combination.
[0140]
Specific examples of the polymer dispersant include polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic acid, and those having a molecular weight of 3000 to 10,000 are preferably used.
[0141]
[Aging process]
The aging step is a step subsequent to the salting-out / fusion step, and the temperature is kept at Tg + 15 to Tg + 40 ° C. of the resin even after the resin particles are fused, and stirring is continued at a constant strength.
[Concentration / washing process]
In this concentration / washing step, a certain amount of aqueous medium is removed from the toner particle dispersion containing toner particles to concentrate the toner particle dispersion to obtain a concentrated toner particle dispersion called a wet cake. This is a step of removing impurities such as free release agent and free colorant particles from the particle surface. Then, the concentrated toner particle dispersion is dispersed again in the cleaning liquid to remove impurities such as surfactants and salting-out agents remaining on the toner particle surfaces.
[0142]
In the present invention, the toner particle dispersion is concentrated using the centrifugal sedimentation device described above, and the toner particle dispersion is concentrated without changing the chargeability of the generated toner particles or deteriorating or damaging the toner particle surface. Impurities can be removed from the toner particle surface.
[0143]
In the present invention, the toner particle dispersion once concentrated may be poured again into washing water, diluted and washed, and the toner particle dispersion may be repeatedly concentrated to more reliably remove impurities from the toner particle surface.
[0144]
In this manner, the toner particle dispersion is repeatedly concentrated and washed to obtain a concentrated toner particle dispersion called a wet cake (cake-like particle aggregate) having a toner particle ratio of around 50%.
[0145]
[Drying process]
This step is a step of drying the washed toner particles.
[0146]
Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.
[0147]
The water content of the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.
[0148]
Next, each component used in the toner manufacturing process will be described in detail.
(Polymerizable monomer)
As a polymerizable monomer for producing the resin (binder) used in the present invention, a hydrophobic monomer is an essential constituent, and a crosslinkable monomer is used as necessary. Moreover, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group in the structure as described below.
[0149]
(1) Hydrophobic monomer
The hydrophobic monomer constituting the monomer component is not particularly limited, and conventionally known monomers can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.
[0150]
Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.
[0151]
Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
[0152]
Examples of (meth) acrylic acid ester monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, Examples include ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. It is done.
[0153]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl benzoate, and examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, and the like. It is done.
[0154]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene, and the diolefin monomer includes butadiene, isoprene, Examples include chloroprene.
[0155]
(2) Crosslinkable monomer
In order to improve the characteristics of the resin particles, a crosslinkable monomer may be added. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.
[0156]
(3) Monomers having acidic polar groups
Examples of the monomer having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH), and (b) a sulfone group (—SOOH)._ThreeMention may be made of α, β-ethylenically unsaturated compounds having H).
[0157]
Examples of the α, β-ethylenically unsaturated compound having a carboxyl group (a) include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid Examples thereof include monooctyl esters and metal salts thereof such as Na and Zn.
[0158]
Examples of the α, β-ethylenically unsaturated compound having a sulfone group (b) include sulfonated styrene and its Na salt, allylsulfosuccinic acid, allylsulfosuccinic acid octyl, and their Na salts. it can.
[0159]
(4) Monomers having basic polar groups
As the monomer having a basic polar group, (a) a (meth) acrylic acid ester of an aliphatic alcohol having 1 to 12, preferably 2 to 8, particularly preferably 2, an amine group or a quaternary ammonium group. , (B) (meth) acrylic acid amide or (meth) acrylic acid amide mono- or disubstituted with an alkyl group having 1 to 18 carbon atoms optionally on N, (c) a heterocyclic ring having N as a ring member Examples thereof include a vinyl compound substituted with a group and (d) N, N-diallyl-alkylamine or a quaternary ammonium salt thereof. Among them, (a) (meth) acrylic acid ester of an aliphatic alcohol having an amine group or a quaternary ammonium group is preferable as a monomer having a basic polar group.
[0160]
Examples of (meth) acrylic acid esters of aliphatic alcohols having an amine group or quaternary ammonium group (a) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the above four compounds. A quaternary ammonium salt, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, etc. can be mentioned.
[0161]
(B) (Meth) acrylic acid amide or (meth) acrylic acid amide optionally mono- or dialkyl-substituted on N includes acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide and the like can be mentioned.
[0162]
Examples of the vinyl compound substituted with a heterocyclic group having N as a ring member in (c) include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like.
[0163]
Examples of N, N-diallyl-alkylamine in (d) include N, N-diallylmethylammonium chloride, N, N-diallylethylammonium chloride and the like.
[0164]
(Polymerization initiator)
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (for example, potassium persulfate, ammonium persulfate, etc.), azo compounds (for example, 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) ) Salt), peroxide compounds and the like. Furthermore, the radical polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. By using a redox initiator, the polymerization activity can be increased, the polymerization temperature can be lowered, and the polymerization time can be shortened.
[0165]
The polymerization temperature is not particularly limited as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but it is, for example, in the range of 50 ° C to 90 ° C. However, it is also possible to polymerize at room temperature or higher by using a polymerization initiator that starts at room temperature in combination with a hydrogen peroxide-reducing agent (such as ascorbic acid).
[0166]
(Chain transfer agent)
A known chain transfer agent can be used for the purpose of adjusting the molecular weight. The chain transfer agent is not particularly limited. For example, octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, ethyl thioglycolate, propyl thioglycolate, propyl thioglycolate, butyl thioglycolate, thioglycol Examples include t-butyl acid, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, and a compound having a mercapto group of ethylene glycol. Among these, n-octyl-3-mercaptopropionic acid ester and n-octyl mercaptan are particularly preferable from the viewpoint of suppressing odor during toner heat fixing.
[0167]
(Surfactant)
In particular, in order to perform miniemulsion polymerization using the above-described polymerizable monomer, it is preferable to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used in this case is not particularly limited, and the following ionic surfactants can be given as examples of suitable compounds.
[0168]
Examples of the ionic surfactant include sulfonate (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol- 6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate sodium, etc.) , Sulfate salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, stearyl Potassium, calcium oleate and the like).
[0169]
In the present invention, surfactants represented by the following general formulas (1) and (2) are particularly preferably used.
[0170]
General formula (1) R₁(OR₂)_nOSO_ThreeM
General formula (2) R₁(OR₂)_nSO_ThreeM
In the general formulas (1) and (2), R₁Represents an alkyl group or arylalkyl group having 6 to 22 carbon atoms, preferably an alkyl group or arylalkyl group having 8 to 20 carbon atoms, more preferably an alkyl group or arylalkyl group having 9 to 16 carbon atoms. is there.
[0171]
R₁As the alkyl group having 6 to 22 carbon atoms represented by, for example, n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, n-undecyl group, n-hexadecyl group, cyclopropyl group , Cyclopentyl group, cyclohexyl group and the like, and R₂Examples of the arylalkyl group represented by the formula include a benzyl group, a diphenylmethyl group, a cinnamyl group, a styryl group, a trityl group, and a phenethyl group.
[0172]
In the general formulas (1) and (2), R₂Represents an alkylene group having 2 to 6 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms. R₂Examples of the alkylene group having 2 to 6 carbon atoms represented by: ethylene group, trimethylene group, tetramethylene group, propylene group, ethylethylene group and the like.
[0173]
In general formula (1), (2), n is an integer of 1-11, Preferably it is 2-10, More preferably, it is 2-5, Most preferably, it is 2-3.
[0174]
In the general formulas (1) and (2), examples of the monovalent metal element represented by M include sodium, potassium, and lithium. Of these, sodium is preferably used.
[0175]
Specific examples of the surfactant represented by the general formulas (1) and (2) are shown below, but the present invention is not limited thereto.
[0176]
  Compound (101): C₁₀H₂₁(OCH₂CH₂)₂OSO₃Na
  Compound (102): C₁₀H₂₁(OCH₂CH₂)₃OSO₃Na
  Compound (103): C₁₀H₂₁(OCH₂CH₂)₂SO₃Na
  Compound (104): C₁₀H₂₁(OCH₂CH₂)₃SO₃Na
  Compound (105): C₈H₁₇(OCH₂CH (CH₃))₂OSO₃Na
  Compound (106): C₁₈H₃₇(OCH₂CH₂)₂OSO₃Na
  (Molecular weight distribution of resin particles and toner)
  The present inventionManufactured inThe toner preferably has a molecular weight distribution peak or shoulder at 100,000 to 1,000,000 and 1,000 to 50,000, and further has a molecular weight distribution peak or shoulder of 100,000 to 100,000. It is preferable that it exists in 1,000,000, 25,000-150,000, and 1,000-50,000.
[0177]
The molecular weight of the resin particles is both a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 50,000. Is preferable, and it is preferable to use an intermediate molecular weight resin having a peak or a shoulder at a portion of 15,000 to 100,000.
[0178]
As a method for measuring the molecular weight of the toner or resin described above, GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a solvent is preferable. That is, 1.0 ml of THF is added to 0.5 to 5 mg of a measurement sample, more specifically 1 mg, and the mixture is sufficiently dissolved by stirring with a magnetic stirrer at room temperature. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., flowing THF at a flow rate of 1.0 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. The column is preferably used in combination with a commercially available polystyrene gel column. For example, Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 made by Showa Denko KK, TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be mentioned. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.
[0179]
(Flocculant)
In the present invention, a metal salt can be preferably used as an aggregating agent in a step of salting out, agglomerating, and fusing resin particles from a dispersion of resin particles prepared in an aqueous medium. More preferably, a metal salt is used as the flocculant. The reason is that a divalent or trivalent metal salt is preferable to a monovalent metal salt because the critical aggregation concentration (coagulation value or coagulation point) is smaller.
[0180]
The flocculant used in the present invention is a monovalent metal salt which is a salt of an alkali metal such as sodium, potassium or lithium, for example, a salt of an alkaline earth metal such as calcium or magnesium, or a divalent such as manganese or copper. Examples thereof include metal salts and trivalent metal salts such as iron and aluminum.
[0181]
Specific examples of these metal salts are shown below. Examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride, and examples of the divalent metal salt include calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. Examples thereof include aluminum chloride and iron chloride. These are appropriately selected according to the purpose, but divalent or trivalent metal salts having a small critical aggregation concentration are preferable.
[0182]
The critical flocculation concentration referred to in the present invention is an index relating to the stability of the dispersion in the aqueous dispersion, and indicates the concentration of the flocculating agent added when the flocculating agent is added. This critical coagulation concentration varies greatly depending on the latex itself and the dispersant. For example, it is described in Seizo Okamura et al., Polymer Chemistry 17,601 (1960), etc., and the value can be known by following these descriptions. As another method, a desired salt is added to the target particle dispersion at a different concentration, the ζ potential of the dispersion is measured, and the salt concentration at the point where the ζ potential begins to change is defined as the critical aggregation concentration. It is also possible to do.
[0183]
In the present invention, the polymer fine particle dispersion is treated with a metal salt so as to have a concentration equal to or higher than the critical aggregation concentration. At this time, as a matter of course, whether the metal salt is added directly or as an aqueous solution is arbitrarily selected according to the purpose. When added as an aqueous solution, the added metal salt must be equal to or higher than the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.
[0184]
In the present invention, the concentration of the metal salt may be not less than the critical aggregation concentration, but is preferably 1.5 times or more, more preferably 2.0 times or more the critical aggregation concentration.
[0185]
  (Coloring agent)
  The present inventionManufactured inThe toner is obtained by salting out / fusing the composite resin particles and the colorant particles. The present inventionManufactured inExamples of the colorant constituting the toner (colorant particles used for salting out / fusion with the composite resin particles) include various inorganic pigments, organic pigments, and dyes. A conventionally well-known thing can be used as an inorganic pigment. Specific inorganic pigments are exemplified below.
[0186]
Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.
[0187]
These inorganic pigments can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0188]
When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 60% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.
[0189]
Conventionally known organic pigments and dyes can also be used, and specific organic pigments and dyes are exemplified below.
[0190]
Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.
[0191]
Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.
[0192]
Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.
[0193]
Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used.
[0194]
These organic pigments and dyes can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2 mass%-20 mass% with respect to a polymer, Preferably it is 3 mass%-15 mass%.
[0195]
  The present inventionManufactured inThe colorant (colorant particles) constituting the toner may be surface-modified. A conventionally well-known thing can be used as a surface modifier, Specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent etc. can be used preferably.
[0196]
Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyltrimethyl. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureido Examples thereof include propyltriethoxysilane.
[0197]
Examples of titanium coupling agents include TTS, 9S, 38S, 41B, 46B, 55, 138S, and 238S, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co., Inc., and commercial products A manufactured by Nippon Soda Co., Ltd. -1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA -30, TSDMA, TTAB, TTOP and the like. Examples of the aluminum coupling agent include “Plenact AL-M” manufactured by Ajinomoto Co., Inc.
[0198]
The addition amount of these surface modifiers is preferably 0.01% by mass to 20% by mass and more preferably 0.1% by mass to 5% by mass with respect to the colorant. Examples of the surface modification method for the colorant particles include a method in which a surface modifier is added to the dispersion of the colorant particles and this system is heated and reacted. The colorant particles whose surface has been modified in this manner are obtained by filtration, and after drying and filtering with the same solvent are repeated, drying is performed.
[0199]
  (Release agent)
  The present inventionManufactured inThe toner is preferably a toner obtained by fusing resin particles containing a release agent in an aqueous medium and appropriately aggregating the release agent in an aging step. In this way, the resin particles containing the release agent in the resin particles are salted out / fused in the aqueous medium with the colorant particles, whereby a toner in which the release agent is finely dispersed can be obtained. Here, the aging step refers to a step in which stirring is continued in the range of the melting point of the release agent ± 20 ° C. even after the resin particles are fused.
[0200]
  The present inventionManufactured inIn the toner, as the releasing agent, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene, and the like are preferable, and ester compounds represented by the following formula are particularly preferable.
[0201]
R₁-(OCO-R₂)_n
In the formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4. R₁, R₂Each represents a hydrocarbon group which may have a substituent. R₁Has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 5 carbon atoms. R₂Has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.
[0202]
Next, the example of a typical compound is shown below.
[0203]
[Chemical 1]

[0204]
[Chemical 2]

[0205]
In the present invention, crystalline polyester can also be used as the release agent. As the crystalline polyester, aliphatic diol and aliphatic dicarboxylic acid (including acid anhydride and acid chloride) are used. Polyester obtained by reaction is preferred.
[0206]
Examples of the diol used to obtain the crystalline polyester include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,4-butenediol. , Neopentyl glycol, 1,5-pentane glycol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A and the like.
[0207]
Dicarboxylic acids used to obtain crystalline polyesters include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, citraconic acid , Itaconic acid, glutamic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, their acid anhydrides or acid chlorides Can be mentioned.
[0208]
Particularly preferred crystalline polyesters include polyesters obtained by reacting 1,4-cyclohexanedimethanol and adipic acid, polyesters obtained by reacting 1,6-hexanediol and sebacic acid, ethylene glycol and succinic acid. And polyester obtained by reacting ethylene glycol and sebacic acid, polyester obtained by reacting 1,4-butanediol and succinic acid, among these, Most preferred is a polyester obtained by reacting 1,4-cyclohexanedimethanol and adipic acid.
[0209]
The amount of the compound added is 1% by mass to 30% by mass, preferably 2% by mass to 20% by mass, and more preferably 3% by mass to 15% by mass with respect to the whole toner.
[0210]
  (Developer)
  The present inventionManufactured inThe toner is used as a two-component developer. That is, a two-component developer in which toner and carrier are mixed. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle diameter of 15 μm to 100 μm, more preferably 25 μm to 80 μm.
[0211]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0212]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.
[0213]
【Example】
Hereinafter, in order to explain the configuration and effects of the present invention, specific embodiments will be shown and described as examples. However, the embodiments of the present invention are not limited thereto.
Production of resin particles
[Resin particles (1HML)]
(1) Preparation of core particles (first stage polymerization):
Anionic surfactant in a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet
Compound (101) C_TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeNa
A surfactant 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 under a nitrogen stream.
[0214]
To this surfactant solution, an initiator solution prepared by dissolving 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., and then 70.1 g of styrene, n -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 this system was polymerized by heating and stirring at 75 ° C for 2 hours (first stage polymerization). Then, resin particles (a dispersion of resin particles made of high molecular weight resin) were prepared. This is referred to as “resin particles (1H)”.
(2) Formation of intermediate layer (second stage polymerization);
In a flask equipped with a stirrer, 105.6 g of styrene, 30.0 g of n-butyl acrylate, 6.2 g of methacrylic acid, 5.6 g of n-octyl-3-mercaptopropionic acid ester, As a crystalline substance, 98.0 g of the compound represented by the above 19) (hereinafter referred to as “Exemplary Compound (19)”) was added, heated to 90 ° C. and dissolved to prepare a monomer solution. .
[0215]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (compound (101)) is dissolved in 2700 ml of ion-exchanged water is heated to 98 ° C., and this surfactant solution is a dispersion of core particles. After adding 28 g of the resin particles (1H) in terms of solid content, the mechanical compound disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation route is used to exemplify the compound (19). The monomer solution was mixed and dispersed for 8 hours to prepare a dispersion (emulsion) containing emulsified particles (oil droplets).
[0216]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion exchange water and 750 ml of ion exchange water are added to this dispersion (emulsion). Polymerization (second-stage polymerization) was carried out by heating and stirring for 12 hours to obtain resin particles (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin was coated with an intermediate molecular weight resin). . This is referred to as “resin particles (1HM)”.
[0217]
When the resin particles (1HM) were dried and observed with a scanning electron microscope, particles (400 to 1000 nm) mainly composed of the exemplified compound (19) not surrounded by the latex were observed.
(3) Formation of outer layer (third stage polymerization):
An initiator solution in which 7.4 g of a polymerization initiator (KPS) is dissolved in 200 ml of ion-exchanged water is added to the resin particles (1HM) obtained as described above, and 300 g of styrene under a temperature condition of 80 ° C. , N-butyl acrylate 95 g, methacrylic acid 15.3 g, n-octyl-3-mercaptopropionic acid ester 10.4 g was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third-stage polymerization) was carried out by heating and stirring for 2 hours, and then cooled to 28 ° C., and resin particles (a central part made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, A dispersion of composite resin particles) having an outer layer made of a low molecular weight resin and containing the exemplified compound (19) in the intermediate layer. This resin particle is referred to as “resin particle (1HML)”.
[0218]
The composite resin particles constituting the resin particles (1HML) had peak molecular weights of 138,000, 80,000 and 13,000, and the mass average particle diameter of the composite resin particles was 122 nm. .
[Resin particles (2HML)]
Resin particles (high molecular weight resin) are obtained in the same manner as the resin particles (1HML) except that 7.08 g of an anionic surfactant (sodium dodecylbenzenesulfonate: SDS) is used instead of the surfactant (101). A dispersion of composite resin particles having a central part made of, an intermediate layer made of an intermediate molecular weight resin, and an outer layer made of a low molecular weight resin. This resin particle is referred to as “resin particle (2HML)”.
[0219]
The composite resin particles constituting the resin particles (2HML) had peak molecular weights of 138,000, 80,000 and 12,000, and the mass average particle diameter of the composite resin particles was 122 nm. .
[Resin particles (3HML)]
Resin particles (high molecular weight resin) are obtained in the same manner as the resin particles (1HML) except that 7.08 g of an anionic surfactant (sodium dodecylbenzenesulfonate: SDS) is used instead of the surfactant (101). A dispersion of composite resin particles having a central part made of, an intermediate layer made of an intermediate molecular weight resin, and an outer layer made of a low molecular weight resin. This resin particle is referred to as “resin particle (3HML)”.
[0220]
The composite resin particles constituting the resin particles (3HML) had peak molecular weights of 138,000, 80,000 and 12,000, and the mass average particle diameter of the composite resin particles was 110 nm. .
Preparation of concentrated toner particle dispersion (wet cake)
Anionic surfactant (sodium dodecyl sulfate) (59.0 g) was dissolved in 1600 ml of ion-exchanged water with stirring, and 420.0 g of carbon black was gradually added while stirring the solution. Then, “CLEAMIX” (M Technique ( A dispersion of colorant particles was prepared by performing a dispersion treatment using a product manufactured by Kogyo Co., Ltd.
[0221]
Resin particle (1HML) 420.7 g (solid content conversion), ion-exchanged water 900 g, colorant dispersion 166 g, a reaction vessel (four-necked) equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device Flask) and stirred. After adjusting the temperature in the container to 30 ° C., a 5 mol / liter sodium hydroxide aqueous solution was added to this solution to adjust the pH to 8.
[0222]
Subsequently, the aqueous solution which melt | dissolved the salting-out agent in 1000 ml of ion-exchange water with the combination of Table 1 was added over 10 minutes at 30 degreeC under stirring.
[0223]
[Table 1]

[0224]
After standing for 3 minutes, the temperature was raised and the system was heated to 90 ° C. over 30 minutes to start particle growth. Measure the particle size of the particles grown with the “Coulter Counter Multisizer” and when the volume average particle size reaches 3 μm, an aqueous solution dissolved in 1000 ml of ion-exchanged water with the combination of Table 1 that contains the salting-out stopper is used. Addition to stop grain growth. Further, as a ripening treatment, the particles were continuously fused by heating and stirring at a liquid temperature of 98 ° C. for 2 hours.
[0225]
Thereafter, the mixture was cooled to 30 ° C., stirring was stopped, and a toner particle dispersion liquid containing 20% by mass of a particulate solid having a volume average particle diameter of 4.5 μm was obtained.
[0226]
Example 1 (Production of Toner 1)
(1) Toner particle concentration process
The toner particle dispersion was introduced into a disk-type centrifugal sedimentation device having a sedimentation plate interval of 0.5 mm and a total sedimentation plate area of 500 times the device installation area shown in FIG. 1, and the rotational speed was set to 3000 rpm and operated. The toner particle dispersion was concentrated. The centrifugal force at this time was 11000G. The toner particle dispersion obtained by concentration was in a state called a wet cake having a solid content of 50%, and 823 g of a concentrated toner particle dispersion was obtained. The resulting concentrated toner particle dispersion is designated as wet cake 1. The time required for concentration at this time was 0.4 seconds per liter of the toner particle dispersion.
(2) Redispersion and reconcentration process of wet cake 1
The wet cake 1 is put into 10000 ml of ion-exchanged water as a cleaning medium, and at the same time, an aqueous solution containing hydrochloric acid is added to adjust the pH to 2.0, and dispersed using a stirring blade for 30 minutes to obtain a toner particle dispersion. Generated. The electric conductivity of the obtained toner particle dispersion was measured with an electric conductivity meter “CM-14P” manufactured by Toa Radio Industry Co., Ltd., and the electric conductivity of the toner particle dispersion was 15 μS / cm. Until the following, the concentration and redispersion of the toner particle dispersion were repeated using the disk-type centrifugal sedimentation apparatus.
(3) Final preparation process
Finally, the toner particles were taken out from the wet cake 1 when the electric conductivity value was 15 μS / cm or less, and the state of impurity adhesion on the surface of 100 toner particles was confirmed with a transmission electron microscope. As a result of confirmation, it was confirmed that one particle had impurities adhered to 100 particles.
(4) Drying process
Thereafter, the wet cake 1 transferred to the vat was put in an oven-type dryer and dried with hot air at 40 ° C. until the water content became 0.63%.
(5) External addition process
The dried colored particles were mixed with 1% by weight of hydrophobic silica to obtain a toner. The obtained toner is designated as Toner 1.
[0227]
  Examples 2 to 5 (Production of Toners 2 to 5)
  Sedimentation of the disk type centrifugal sedimentation deviceBoardToner 2 was obtained by repeating the concentration and redispersion of the toner particle dispersion in the same manner as in Example 1 except that the interval was 1.0 mm, and the area of the total sedimentation plate with respect to the apparatus installation area was 200 times. At this time, the processing time per liter of the toner particle dispersion was 0.8 seconds.
[0228]
  Similarly, sedimentationBetween boardsThe distance obtained by setting the space of 0.25 mm and the total sedimentation plate area with respect to the apparatus installation area to 1000 times is set to toner 3, 2.0 mm, and 100 times, and the toner is set to toner 4, 10 mm, and 10 times. The obtained toner was named Toner 5. The average processing times per liter of the toner particle dispersion of toners 3, 4, and 5 were 0.2 seconds, 1.5 seconds, and 3.5 seconds, respectively. Table 2 shows the number of impurity particles in 100 toners.
[0229]
Examples 6 and 7 (Production of Toners 6 and 7)
A toner 6 was obtained in the same manner as in Example 1 except that the aging after the volume average particle size of the particles in Example 1 was not performed was 3 μm. Further, a toner 7 was obtained in the same manner as in Example 1 except that the aging treatment was continued and the heat stirring was extended at a liquid temperature of 98 ° C. to continue particle fusion. Table 2 shows the number of impurity particles in 100 toners.
[0230]
Examples 8 to 13 (Production of Toners 8 to 13)
Toner 8 was obtained in the same procedure as in Example 1 except that the pH of the cleaning liquid when the wet cake 1 of toner particles in Example 1 was put into the cleaning medium was set to 4.5. In addition, toner 9 was obtained by setting the pH of the cleaning liquid to 6.5.
[0231]
Further, toners obtained by using cleaning liquids having a pH of 8, 10, 12, and 14 by adding sodium hydroxide were designated as 10, 11, 12, and 13, respectively. Table 2 shows the impurity adhesion amount per 100 particles of each toner obtained.
[0232]
Comparative Example 1 (Comparative Toner 1)
A comparative toner 1 was obtained in the same manner as in Example 1 except that the steps (1) to (3) were omitted. Table 2 shows the number of impurity particles in 100 obtained toners.
[0233]
Comparative Example 2 (Comparative Toner 2)
In Example 1, in place of the centrifugal sedimentation device, the obtained toner particle dispersion is put into a centrifuge tank in which a nonwoven fabric filter cloth is set, and the centrifuge is operated under the condition of acceleration of 700G. Thus, a comparative toner 2 was obtained through a step of concentrating the toner particle dispersion. Table 2 shows the number of impurity particles in 100 obtained toners.
[0234]
Comparative Example 3 (Comparative Toner 3)
In Example 1, a toner 3 for comparison was obtained through a step of concentrating the toner particle dispersion using a decanter centrifuge described in JP-A-2001-194826 instead of the centrifugal sedimentation apparatus. Table 2 shows the number of impurity particles in 100 obtained toners.
[0235]
Table 2 shows the performance of the toner. In Table 2, the volume average particle diameter of the toner particles was measured by Coulter Counter TA-II, and the impurity content per 100 particles was evaluated by a transmission electron micrograph.
[0236]
[Table 2]

[0237]
As is clear from the results in Table 2, it was confirmed that impurities were removed from the toner particle surfaces obtained by the production method according to the present invention.
[0238]
Live-action evaluation
As the image forming apparatus, a commercially available digital copying machine Sitoos 7165 (manufactured by Konica) was used. The digital copying machine was evaluated under the following conditions.
[0239]
Charging conditions
Charger: Scorotron charger, initial charge potential of -750V
Exposure conditions
The exposure part potential was set to -50V.
Development conditions
DC bias set to -550V
Transcription conditions
Corona charging method.
[0240]
In addition, as a fixing device, a heating roller using iron as a core metal and having a surface roughness Ra of 0.8 μm coated with PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having a thickness of 25 μm. Was used, and an iron cored bar was used as a pressure roller, and a pressure roller having a surface roughness Ra of 0.8 μm, in which a PFA tube having a thickness of 120 μm was coated on HTV silicone rubber, was used. The nip width is 3.8 mm, and the linear velocity is 420 mm / sec.
[0241]
The cleaning mechanism for the fixing device and the silicon oil supply mechanism are not installed. The fixing temperature was controlled by the surface temperature of the heating roller, and was set to 165 ° C.
[0242]
As the developer, a silicone-coated carrier having a volume average particle diameter of 60 μm was used and mixed with each toner so that the toner mass concentration was 6%.
[0243]
As copying conditions, 1 million sheets were printed continuously in a high temperature and high humidity environment (30 ° C., 83% RH), and the following items were evaluated for copy images after printing 1 million sheets continuously. The copy image was printed on an A4 transfer paper at an equal magnification using a character document having an A4 size blackened area ratio of 5%.
(1) Change in charge amount over time
Qa is the amount of charge when the developer is set and the first image is output, and Qb is the amount of charge when 1 million images are output, and Qb / Qa is
A: 0.9 or more and less than 1.1
○: 0.8 or more and less than 0.9, or 1.1 or more and less than 1.2
Δ: 0.7 or more and less than 0.8, or 1.2 or more and less than 1.3
X: Less than 0.7 or 1.3 or more
(2) Photoconductor filming
The surface of the photoreceptor after the above-mentioned continuous 1 million copies was visually observed, and the presence or absence of uneven halftone due to filming was determined.
[0244]
A: A uniform image with no unevenness is obtained, and no filming is observed.
○: Although streaky thin unevenness exists, there is no practical problem, and no filming on the surface of the photoreceptor is observed.
Δ: Striped thin unevenness is present and slight filming is confirmed on the surface of the photoreceptor, but there is no practical problem.
X: Several or more streak-like unevenness exists, and clear filming is recognized on the surface of the photoreceptor, which is problematic in practical use.
(3) fog
The relative density with respect to the unused transfer sheet in the white background portion of the copy image area after continuous 1 million copies was measured using a Macbeth densitometer.
[0245]
A: Relative concentration 0 to less than 0.002
○: Relative concentration 0.002 or more and less than 0.003
Δ: Relative concentration 0.003 or more and less than 0.005
X: Relative density 0.005 or more.
(3) Cleaning failure
Evaluation was made based on the number of copies that started to contaminate the white background due to toner slipping from the cleaning section.
(4) Halftone dot reproducibility
With a Macbeth reflection densitometer “RD-918” for a 10% halftone dot image portion of 20 mm × 20 mm, the reproducibility of the first and millionth dots was evaluated. If the density change was less than 0.10, the image quality change was small and it was evaluated that there was no problem.
(5) Line width
The reproducibility of the line width of the line image corresponding to the image signal of 2 dot lines was evaluated by a print evaluation system “RT2000” (manufactured by Yarman). The evaluation was performed with respect to the line width and line width variation of the first and one million line images.
[0246]
◎ Both the first and one millionth line widths are 200 μm or less, and the line width change is less than 0 to 5 μm.
○ Line width of the 1st sheet and 1st sheet is both 200μm or less, and the line width change is 5μm or more and less than 10μm
Δ: The line width of the first sheet is slightly over 200 microns, but the line width of the first million sheets is 200 μm or less, and the line width change is less than 10 μm.
×: Line widths of the first and one million sheets both exceed 200 μm, and the change in line width exceeds 10 μm
(6) Character collapse
After copying 1 million sheets, character images of 3 points and 5 points were formed and evaluated using a loupe according to the following criteria.
[0247]
◎: 3 points and 5 points are clear and easy to read
○: Some characters are unreadable in 3 points, but can be read with a loupe, 5 points are clear and easy to read
X: Most of the 3 points are unreadable even with a loupe, and 5 points are partially or completely unreadable visually.
(7) Tonal variation
A halftone image having a reflection density value of 0.3 was formed at the start and after copying 1 million sheets, and the density fluctuation was evaluated.
[0248]
A: Density fluctuation after initial and 1 million copies is within 0.3 ± 0.05
○: Density fluctuation after initial and 1 million copies is within 0.3 ± 0.1
×: Density fluctuation after initial and 1 million copies exceeds 0.3 ± 0.1.
[0249]
The above results are shown in Table 3.
[0250]
[Table 3]

[0251]
As is apparent from the above evaluation results, in Examples 1 to 13 which are toners produced by the production method according to the present invention, there is no fluctuation in charging property even after continuous copying of 1 million sheets under high temperature and high humidity. A very stable toner was obtained, and no photoconductor filming or poor cleaning was observed even in image formation under the above environment. Further, no fog was generated even after continuous copying of 1 million sheets, and halftone dot reproducibility, line width, fine line reproducibility without losing characters was excellent, and an image with good halftone image quality was obtained.
[0252]
It has been confirmed that the toner obtained by the production method according to the present invention can reproduce the image quality performance required for a digital image forming apparatus, such as fine line reproducibility and halftone image reproducibility, after continuous copying of 1 million sheets. It was.
[0253]
In the present invention, after carrying out the present embodiment, continuous copying of 5 million sheets and 10 million sheets was further performed and the above evaluation was performed, and it was found that good results were obtained in both cases.
[0254]
【The invention's effect】
  In the present inventionAccording toIn the toner particles obtained by concentrating the toner particle dispersion with a centrifugal sedimentation device, it was confirmed that no impurities remained on the toner particle surfaces, and no impurities remained on the toner particle surfaces. It was confirmed that even when continuous printing exceeding 10,000 sheets was performed over a long period of time, a toner having a mechanically stable strength was obtained without fluctuation of the chargeability on the surface of the toner particles.
[Brief description of the drawings]
FIG. 1 shows the production of a toner according to the present invention.Including methodsFlowThisIt is a schematic diagram shown.
FIG. 2 is a diagram showing movement of a dispersion medium containing toner particles and impurities in a toner particle dispersion in a disk-type centrifugal sedimentation apparatus used in the present invention.
FIG. 3 is a diagram showing automatic discharge of a concentrated toner particle dispersion by opening and closing a joint of a disk type centrifugal sedimentation device used in the present invention.
FIG. 4 is a schematic diagram showing the location of each component in the separated sedimentation area formula.
FIG. 5 is a schematic diagram showing an example of the particle structure of toner particles produced according to the present invention.
[Explanation of symbols]
  1 Centrifugal sedimentation device
  2 Upper member
  3 Rotor
  4 Lower part
  5 Concentration chamber
  6 joints
  7 Lower member operation room
  10 Settling plate
  12 Liquid accumulation chamber
  15 Delivery pipe
  17 Delivery pipe
  30 Collection Department
  R toner particles

Claims (4)

A method for producing a toner, wherein resin particles are salted out / fused in an aqueous medium to form toner particles, and the toner is produced through a state of a toner particle dispersion,
The toner manufacturing method includes a centrifugal sedimentation device provided with a plurality of sedimentation plates that are opened downward and arranged in a conical shape at intervals of 0.25 mm or more and 1.0 mm or less in a storage unit that stores a toner particle dispersion. Use
A toner particle dispersion having a toner particle concentration of 8 mass% or more and 40 mass% or less is applied with a centrifugal force of 5000 G or more and 15000 G or less, and the toner particles contained in the toner particle dispersion liquid are centrifugally settled to disperse the toner particles. While concentrating the liquid,
Automatically discharging the concentrated toner particle dispersion out of the centrifugal settling device;
A method for producing toner, wherein an automatic discharge time when the concentrated toner particle dispersion is automatically discharged out of the centrifugal sedimentation apparatus is 1 second or less per liter of the concentrated toner particle dispersion. 2. The method for producing toner according to claim 1, wherein the toner particle dispersion or the concentrated toner particle dispersion has a pH of 2 to 6.5. The method for producing a toner according to claim 1, wherein the toner particle dispersion or the concentrated toner particle dispersion has a pH of 8 to 12. The automatically discharged concentrated toner particle dispersion is diluted in an aqueous medium, the diluted toner particle dispersion is concentrated again by a centrifugal sedimentation device, and the automatic discharge of the concentrated toner particle dispersion is repeated. Item 4. The method for producing a toner according to any one of Items 1 to 3.

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