JP4182704B2 - Toner manufacturing apparatus, method and toner for developing electrostatic image - Google Patents

Description

【０１７２】
【化２】

【０１７３】
また、本発明では結晶性物質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。
【０１７４】
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。
【０１７５】
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。
【０１７６】
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。
【０１７７】
上記化合物の添加量は、トナー全体に対し１〜３０質量％、好ましくは２〜２０質量％、更に好ましくは３〜１５質量％である。
【０１７８】
（現像剤）
本発明のトナーは、一成分現像剤でも二成分現像剤として用いてもよく、一成分現像剤として用いる場合は、非磁性一成分現像剤、あるいはトナー中に０．１〜０．５μｍ程度の磁性粒子を含有させた磁性一成分現像剤が挙げられいずれも使用できる。
【０１７９】
また、キャリアと混合して二成分現像剤として用いることもでき、この場合は、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１５〜１００μｍ、より好ましくは２５〜８０μｍのものがよい。
【０１８０】
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。
【０１８１】
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。
【０１８２】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されるものではない。なお、文中「部」とは「質量部」を表す。
トナー分散液の調整
トナー分散液１
トナー用樹脂粒子の製造例
〔ラテックス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
（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。
【０１８３】
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、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（１Ｈ）」とする。
（２）中間層の形成（第二段重合）；
攪拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．２ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル５．６ｇからなる単量体混合液に、結晶性物質として、上記式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。
【０１８４】
一方、アニオン系界面活性剤（上記式（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ラテックス（１Ｈ）を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）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。
【０１８５】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を９８℃にて１２時間にわたり加熱攪拌することにより重合（第二段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを「ラテックス（１ＨＭ）」とする。
【０１８６】
前記ラテックス（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ラテックス（１ＨＭ）に、重合開始剤（ＫＰＳ）７．４ｇをイオン交換水２００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン３００ｇ、ｎ−ブチルアクリレート９５ｇ、メタクリル酸１５．３ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル１０．４ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱攪拌することにより重合（第三段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層に例示化合物（１９）が含有されている複合樹脂粒子）の分散液を得た。このラテックスを「ラテックス（１ＨＭＬ）」とする。
【０１８７】
このラテックス（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重量平均粒径は１２２ｎｍであった。
〔トナー分散液１〕
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を徐々に添加し、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。
【０１８８】
ラテックス（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／Ｌの水酸化ナトリウム水溶液を加えてｐＨを８に調整した。
【０１８９】
次いで、塩化マグネシウム・６水和物１２．１ｇ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。３分間放置した後に昇温を開始し、この系を６〜６０分間かけて９０℃まで昇温し、会合粒子の生成を行った。その状態で、「コールターカウンター ＴＡ−II」にて会合粒子の粒径を測定し、個数平均粒径が６．４μｍになった時点で、塩化ナトリウム８０．４ｇをイオン交換水１０００ｍｌに溶解した水溶液を添加して粒子成長を停止させ、更に熟成処理として液温度９８℃にて２時間加熱攪拌することにより、粒子の融着を完結させた。
【０１９０】
その後、３０℃まで冷却し、塩酸を添加してｐＨを４．５に調整し、トナー分散液を得た。得られたトナー分散液をトナー分散液１とする。
〔トナー分散液２〕
トナー分散液１の調製において、会合粒子が４．３μｍに成長した時点で塩化ナトリウム水溶液を添加した以外は同様にして、トナー分散液２を得た。
〔トナー分散液３〕
スチレン１６５ｇ、ｎ−ブチルアクリレート３５ｇ、カーボンブラック１０ｇ、ジ−ｔ−ブチルサリチル酸金属化合物２ｇ、スチレン−メタクリル酸共重合体８ｇ、パラフィンワックス（ｍｐ＝９０℃）２０ｇを６０℃に加温し、ＴＫホモミキサー（特殊機化工業社製）にて１２，０００ｒｐｍで均一に溶解、分散した。これに重合開始剤として２，２′−アゾビス（２，４−バレロニトリル）１０ｇを加えて溶解させ、重合性単量体組成物を調製した。
【０１９１】
ついで、イオン交換水７１０ｇに０．１Ｍ燐酸ナトリウム水溶液４５０ｇを加え、ＴＫホモミキサーにて１３０００ｒｐｍで攪拌しながら１．０Ｍ塩化カルシウム６８ｇを徐々に加え、燐酸三カルシウムを分散させた懸濁液を調製した。この懸濁液に上記重合性単量体組成物を添加し、ＴＫホモミキサーにて１００００ｒｐｍで２０分間攪拌し、重合性単量体組成物を造粒し、その後、塩酸により燐酸三カルシウムを溶解除去し、トナー分散液３を得た。トナー分散液３中でのトナーの体積平均断面粒径Ｄｖ５０は、７．２μｍであった。
〔トナー分散液４〕
例示化合物（１９）３０質量部を酢酸エチル２５０質量部に加熱溶解させた後、液体窒素で急激に冷却析出させて離型剤の酢酸エチル分散液を得た。離型剤の平均粒子径は、レーザー回折／散乱粒度分布測定装置ＬＡ−７００（堀場製作所（株）製）で測定したところ、０．６μｍだった。ビスフェノールＡプロピレンオキサイド付加物、ビスフェノールＡエチレンオキサイド付加物、およびテレフタル酸誘導体からなるポリエステル樹脂（Ｍｗ：２００００，Ｔｇ：６６℃，Ｔｍ：１０６℃）１００質量部、カーボンブラックを８質量部、酢酸エチル８０質量部をボールミルで１０時間混合分散後、例示化合物（１９）の酢酸エチル分散液３６質量部を加え、均一になるまでよく撹拌した。この液をＡ液とする。
【０１９２】
一方、炭酸カルシウム６０質量部、水４０質量部をボールミルで１０時間混合分散後、炭酸カルシウム分散液７質量部とセロゲンＢＳ−Ｈ（第一工業製薬（株）製）の２％水溶液１００質量部をクッキングミキサーＭＸ−９１５Ｃ（松下電器（株）製）にいれて、５分間攪拌した。この液をＢ液とする。
【０１９３】
攪拌機を用いて前記Ｂ液５０質量部と前記Ａ液５０質量部を攪拌混合し、懸濁液とした。その後、減圧下で溶媒を除去した。次に６ｍｏｌ／Ｌ塩酸を１００質量部加えて、炭酸カルシウムを溶解除去し、トナー分散液４を得た。トナー分散液４中でのトナーの体積平均断面粒径Ｄｖ５０は、５．１μｍであった。
〔スクリーンの調整とスクリーン通過工程〕
表１に示すスクリーン１〜８を用意した。各スクリーンは、スクリーンのスリット幅（ワイヤ間隙）、ワイヤの断面形状、エッジの曲率半径、及び素材の条件を変化させたものである。また、後述する比較例２と比較例３で用いた比較用スクリーン２と３を用意した。スクリーンを図１〜３に示すスクリーン固定装置に設置した。
【０１９４】
スクリーンを構成するワイヤの直径は７０μｍである。
また、ワイヤを構成するニッケル合金は、インコロイ８５５（ＪＩＳＧ４９０１、４９０２、４９０３、４９０４）を、ステンレススチール（ＳＵＳ）は、ＳＵＳ３１６を使用した。
【０１９５】
【表１】

【０１９６】
上記スクリーン１〜８を図１〜図３に示すトナー分散液通過装置に装填して、前述のトナー分散液を通過させて、表２に示す様に本発明に係るトナー１〜トナー１６と比較用トナー１〜４を生成した。
【０１９７】
トナー１〜１４と比較用トナー２と３は、円筒形にしたスクリーンを図２に示すトナー分散液通過装置に装填してトナー分散液を通液して得た。トナー１５は図３に示すトナー分散液通過装置にスクリーン１を装填してトナー分散液の通過を行ったもので、トナー１６はスクリーン１をフラット形状にして、図１に示すトナー分散液通過装置に装填して得た。
【０１９８】
各トナー分散液は、スクリーンを構成するワイヤが、その断面形状における直線部分でスクリーン面を構成しており、該直線部分の向いているスクリーン面よりトナー分散液の通液を行った。
【０１９９】
なお、比較例として、スクリーン通過を行わなかったものを比較例１、スクリーン５のワイヤの断面形状における直線部分が向いている面の逆側をスクリーン面として、図３のトナー分散液通過装置に装填しトナー分散液通過を行ったものを比較例４とした。
【０２００】
また、ドレインを使用の場合は、送液を４時間行ったら、２時間の送液停止時間を設け、スクリーン固定装置内の不要残さを排出した。
〔固液分離工程、乾燥工程、及び外部添加剤混合工程〕
スクリーンを通過させた各トナー分散液を濾布を設置した遠心分離濾過装置を用い、４５℃のイオン交換水で繰り返し洗浄を行い、その後、４０℃の温風で乾燥したのち、疎水性シリカ１質量％と混合することにより、表２に示す組み合わせのトナー１〜１６を得た。また、以下の手順で比較用トナー１〜４を得た。
比較用トナー１
トナー分散液１をスクリーン通過工程を経ることなく固液分離、乾燥、及び疎水性シリカを１質量％となるように添加混合して比較用トナー１を得た。
比較用トナー２〜４
トナー分散液１を表１に示すスクリーンに通過させたのち固液分離、乾燥、及び疎水性シリカ１質量％となる様に添加混合して比較用トナー２〜４を得た。比較用トナー２、３は、表１に示す様にワイヤの断面形状が円で、その断面形状に直線部分を有するものではない。
【０２０１】
また、比較用トナー４は、トナー５を製造する時に使用したスクリーン５を裏返しにして図２のトナー分散液通過装置に設置した。すなわち、ワイヤの断面形状は直線部分を有するが、該直線部を有する面の逆側よりトナー分散液の送液を行った。
【０２０２】
なお、比較用トナー２〜４ではスクリーンの目詰まりが発生したため、送液を停止し、手作業で清掃することで継続したが、きわめて生産性の低いものであった。各トナー１〜１６及び比較用トナー１〜４を表２に示す。
【０２０３】
また、透過型電子顕微鏡にて生成された各トナー粒子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。その結果を表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個あたりの不純物の付着量は透過型電子顕微鏡写真により評価した。
【０２０４】
また、表２中のトナー分散液通過速度は、前述の中央工測社製の３次元流速計を使用して測定を行い、図１に示されるフラットなスクリーンを使用した時はスクリーンの中心点とスクリーンの外縁及び中心点と外縁の中点における流速より平均流速を求めた。
【０２０５】
さらに、本実施例では、超音波工業社製の磁歪型ニッケル振動子超音波発生装置を用いて超音波を付与してスラリーのスクリーン通過を行った。
【０２０６】
【表２】

【０２０７】
次に、本発明に係る各トナー１〜１６及び比較用トナー１〜４に、体積平均粒径６０μｍのフェライトキャリアをトナー濃度が６％となる様混合して、表３に示す様に２成分系現像剤である現像剤１〜１６及び比較用現像剤１〜４を得、それぞれ実施例１〜１６、比較例１〜４とした。
【０２０８】
【表３】

【０２０９】
実写評価
市販のデジタル複写機Ｓｉｔｉｏｓ７０３５（コニカ社製）に各現像剤をセットし、連続７５万枚の連続コピーを行い、連続７５万枚後のコピー画像について、以下の項目について評価を行った。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コピーを行った。
【０２１０】
評価は、超高湿環境（３０℃、９０％ＲＨ）にて実施した。
（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，７５万枚の画像を出したときの帯電量をＱｂとし、両者の比Ｑｂ／Ｑａを評価した。
【０２１１】
◎ ： Ｑｂ／Ｑａの値が０．９以上１．１未満
○ ： Ｑｂ／Ｑａの値が０．８以上０．９未満又は１．１以上１．２未満
△ ： Ｑｂ／Ｑａの値が０．７以上０．８未満又は１．２以上１．３未満
× ： Ｑｂ／Ｑａの値が０．７未満又は１．３以上
とした。
（２）初期のかぶり
初期段階において、白地画像を印字し、コニカデンシトメーター（コニカ社製）にて転写紙に対する相対濃度を測定した。評価基準は下記とした。
【０２１２】
◎ ： ０．０００以上０．００２未満
○ ： ０．００２以上０．００４未満
△ ： ０．００４以上０．００９未満
× ： ０．００９以上
（３）階調性変動
初期相対濃度が０．３〜０．４となるパッチ画像を形成し、７５万枚コピー後の濃度変化ΔＤにより評価した。
【０２１３】
◎ ： ΔＤ＝０．０００以上０．００３未満
○ ： ΔＤ＝０．００３以上０．００６未満
△ ： ΔＤ＝０．００６以上０．０１未満
× ： ΔＤ＝０．０１以上
以上の結果を表４に示す。
【０２１４】
【表４】

【０２１５】
表４の結果より明らかな様に本発明に係る製造方法を経て得られた静電荷像現像用トナーは、経時的に安定な帯電性を有するとともに、初期段階においてカブリが殆ど発生することなく、階調性変動の少ない良好な安定した画質を有するトナー画像の得られることが確認された。
【０２１６】
特に、本発明に係る製造方法によって得られたトナーは、３０℃、９０％ＲＨの超高湿環境という過酷な環境下でも安定したトナー画像の得られることが確認された。これは、従来電子写真機器メーカーで保証される静電荷像現像用トナーの使用環境が、１０℃、２０％ＲＨから３０℃、８０％ＲＨという範囲のものよりも過酷な環境下で、本発明により得られた静電荷像現像用トナーでは良好な性能を発揮できることが確認された。
【０２１７】
なお、本発明では、本実施例実施後、さらに１５０万枚、４５０万枚及び７５０万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確認された。
【０２１８】
【発明の効果】
実施例の結果から明らかな様に、本発明に係る製造装置によりスラリーをスリット通過させる工程を経て得られたトナー粒子は、トナー粒子表面に不純物が全く残存していないので、高温高湿下で数１０万枚を超える環境下で長期連続の画像形成を行ってもトナー粒子表面における帯電量変化しないことが確認された。
【０２１９】
また、本発明により得られたトナー粒子を使用した画像形成では、３０℃、９０％ＲＨという超高温高湿下で７５万枚にわたる長期連続コピーを行っても画質変動のない安定したトナー画像が得られることが確認され、過酷な環境条件や画像形成条件下でも帯電性変動の発生しないトナー粒子による安定した画像形成技術が確立された。
【図面の簡単な説明】
【図１】ワイヤを円盤状に捲装してなるスクリーンを配置したトナー分散液通過装置の模式図である。
【図２】ワイヤを円筒状に捲装し円筒の外側より内側に向けてトナー分散液の通過を行うトナー分散液通過装置の模式図である。
【図３】ワイヤを円筒状に捲装し円筒の内側より外側に向けてトナー分散液の通過を行うトナー分散液通過装置の模式図である。
【図４】ワイヤを間隔を開けて配置してなるスクリーンの例を示す模式図である。
【図５】ワイヤの断面形状の例を示す模式図である。
【図６】スクリーンにスラリーを通過させた状態を示す模式図である。
【図７】スラリーのスリット通過時におけるスクリーン面の形状がスラリーの通過に与える影響を説明する模式図である。
【図８】本発明で製造されるトナー粒子の構造の例を示す模式図である。
【符号の説明】
１ トナー分散液通過装置
２ スクリーン
３ トナー分散液入口
４ トナー分散液出口
２１ 固体部材（ワイヤ）
２２ スリット（隙間）
２３ スクリーン面
２０１ ワイヤ（固体部材）の断面部
２０２ ワイヤ（固体部材）の断面部における直線部分に隣接する線分
２０３ ワイヤ（固体部材）の断面部における直線部分
２０４ ワイヤ（固体部材）の断面部におけるエッジ部分
Ｔ トナー粒子
ｐ スリットの幅
ｒ 曲率半径
ｓ スクリーン面上方
ｔ スクリーン面中央
ｕ スクリーン面下方[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic charge image developing toner manufacturing apparatus, manufacturing method, and toner used in a copying machine, a printer, and the like. Specifically, the present invention relates to a cleaning technique that effectively removes impurities adhering to the surface of toner particles.
[0002]
[Prior art]
In recent years, it has been found that, in a polymerized toner obtained by a suspension polymerization method or an emulsion polymerization method, the particle size and shape of the toner can be controlled by controlling the polymerization process in an aqueous medium. Japanese Patent Application Laid-Open No. 2000-214629 discloses that a toner having a small particle size and a uniform distribution and having rounded corners on the particles can be obtained. Thus, the polymerized toner obtained through the polymerization process in the aqueous medium is attracting attention as a toner capable of reproducing a small dot image for a digital image because of its fine line reproducibility and high resolution.
[0003]
As described above, the polymerized toner generates particles by a polymerization process in an aqueous medium, and finally separates the generated particles from the aqueous medium to obtain toner particles. The aqueous medium that generates particles contains impurities such as surfactants, dispersion stabilizers, and colorant particles that have not been incorporated into the particles, and these impurities adhere to the surface of the generated particles. Therefore, careful cleaning is performed in order to remove these impurities in the production process after the production of the particles. JP-A-2000-292976 discloses a technique relating to the removal of impurities from the surface of the generated particles, while performing solid-liquid separation by centrifugation, supplying water until the filtrate has a conductivity lower than a specific value, and washing the particles. In JP 2001-249490 A, a cleaning liquid is added to a slurry of toner particles in a container equipped with a stirring blade and a filter medium, and the slurry is stirred, and the slurry is passed through the filter medium under pressure. An apparatus in which the cleaning liquid removal operation is repeated several times is disclosed.
[0004]
However, it is found that the toner obtained through the cleaning methods disclosed in these documents gradually increases the charge amount when stirring in the developing unit for a long time after being put into the image forming apparatus is continued. In an image forming apparatus installed in a continuous high-temperature and high-humidity environment such as continuous copying of several hundred thousand sheets or more, fogging is observed, and halftone or halftone due to image unevenness is generated. There is a problem in that the density variation of the point image or the gradation variation occurs.
[0005]
In addition, as an effective means for removing impurities remaining on the toner particle surface, it is known to perform acid or alkali treatment in the washing step. May generate insoluble impurities. Therefore, a toner particle cleaning technique that mechanically removes residual impurities on the surface of the toner particles without performing acid or alkali treatment has been desired.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the circumstances as described above, and its object is to remove impurities from a toner particle surface obtained by forming particles in an aqueous medium mechanically and reliably. Provided is a method for producing a toner for developing an electrostatic image capable of obtaining stable toner particles which do not cause a change in chargeability even when a continuous image is formed over a long period of time in a high humidity environment and over several hundred thousand sheets. It is to be.
[0007]
The second object of the present invention is to reduce the weakly chargeable toner by not having impurities remaining on the surface of the toner particles, and is not affected by the environment in which fog and image unevenness do not occur particularly in a high temperature and high humidity environment. It is an object of the present invention to provide a method for producing a toner for developing an electrostatic charge image and a production apparatus therefor that can obtain stable toner particles.
[0008]
[Means for Solving the Problems]
Inventors and others have made daily studies to form particles in an aqueous medium, and a slurry-like dispersion containing the formed toner particles is formed on a screen surface composed of wires having a specific cross-sectional shape. It has been found that stable toner particles that do not generate chargeability fluctuations over a long period of time can be obtained by passing through the slits.
[0009]
That is, according to the present invention, impurities are removed from the surface of the toner particles only by passing the slurry dispersion through the slit without performing acid or alkali treatment on the dispersion containing toner particles formed in an aqueous medium. It has been found that a stable toner can be obtained that can be removed neatly and does not change its chargeability over a long period of time.
[0010]
The clear reason why the effect of the present invention that the residual impurities are efficiently removed from the surface of the toner particles simply by passing the slurry-state toner particle dispersion through the slit on the screen is not clear, but the toner particles are probably When the toner particles pass through a narrow slit, they collide violently with each other, rub, and sharpen. It is guessed.
[0011]
In this way, the present invention can remove impurities from the toner particle surface only by mechanical treatment, so that water-insoluble impurities caused by hydrolysis, which has become a problem when chemical treatment such as acid or alkali treatment, is performed. Impurities can be completely removed from the toner particle surface without worrying about the occurrence and with a much smaller amount of water than when chemical treatment is performed. That is, the present invention is achieved by any one of the following configurations.
[0012]
  [1] An electrostatic charge image developing toner manufacturing apparatus that forms particles in an aqueous medium and passes through a slurry state, the manufacturing apparatus having a slit through which the slurry passes.Formed of wireHave screenAnd
  The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
  The curvature radius of the curved surface is 1 μm or more and 20 μm or less.An apparatus for producing a toner for developing an electrostatic charge image.
[0013]
  [2]An electrostatic charge image developing toner manufacturing apparatus that forms particles in an aqueous medium and passes through a slurry state, the manufacturing apparatus having a screen formed of a wire having a slit through which the slurry passes,
  The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
  The radius of curvature of the curved surface is not less than 0.25 times and not more than 5 times the average particle diameter Dv50 of the toner particles.It is characterized byStillAn apparatus for producing toner for developing a charge image.
[0014]
  [3] The screen is characterized in that the screen surface is formed with the straight portion in the cross-sectional shape of the wire as the same side.[1] orThe apparatus for producing a toner for developing an electrostatic charge image according to [2].
[0015]
  [4] The slit of the screen is formed by arranging the wires in parallel at a predetermined interval.[1] ~[3]Any one of2. An apparatus for producing a toner for developing an electrostatic image according to 1.
[0016]
  [5] The cross-sectional shape of the wire has a substantially triangular shape.[1]The apparatus for producing toner for developing electrostatic images according to any one of [4] to [4].
[0019]
  [6]The width of the slit of the screen is 15 μm or more and 50 μm or less.[5]The apparatus for producing an electrostatic charge image developing toner according to any one of the above.
[0020]
  [7]The wire is made of a nickel alloy,[1]~[6]The apparatus for producing an electrostatic charge image developing toner according to any one of the above.
[0021]
  [8][1] to [1], wherein the device having the screen has a drain.[7]The apparatus for producing an electrostatic charge image developing toner according to any one of the above.
[0022]
  [9][1] to [1], characterized by comprising control means for controlling the slurry conveying speed so that the speed of the slurry when passing through the screen is 12.5 cm / min or more and 167 cm / min or less.[8]The apparatus for producing an electrostatic charge image developing toner according to any one of the above.
[0023]
  [10]The apparatus has a frequency of 10 kHz to 38 kHz and a power density of 0.01 W · cm on the screen.^-20.5W · cm^-2[1] to [1], characterized by having an ultrasonic application device for applying the following ultrasonic waves[9]The apparatus for producing an electrostatic charge image developing toner according to any one of the above.
[0024]
  [11]A method for producing a toner for developing an electrostatic charge image by forming particles in an aqueous medium and passing through a slurry state, the method comprising producing particles contained in a slurry.Formed of wireHaving the process of passing through the slit of the screenIs,
  The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion, and the curvature radius of the curved surface. Is not less than 1 μm and not more than 20 μmA method for producing a toner for developing an electrostatic charge image.
[0025]
  [12] A method for producing a toner for developing an electrostatic charge image in which particles are formed in an aqueous medium and pass through a slurry state, wherein the particles are contained in the slurry in a slit of a screen formed from a wire. Having a process of passing,
  The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
  The curvature radius of the curved surface is 0.25 to 5 times the average particle diameter Dv50 of the toner particles.It is characterized byStillA method for producing a toner for developing a charge image.
[0026]
  [13]The step of allowing the particles contained in the slurry to pass through the slit of the screen is allowed to pass from the screen surface side constituted by the linear portion in the cross-sectional shape of the wire.[11] or [12]A method for producing a toner for developing an electrostatic image as described in 1.
[0029]
  [14]The speed at which the slurry passes in the passing step is 12.5 cm / min or more and 167 cm / min or less,Any one of [11]-[13]A method for producing a toner for developing an electrostatic image as described in 1.
[0030]
  [15]The screen has a frequency of 10 kHz to 38 kHz and a power density of 0.01 W · cm.^-20.5W · cm^-2The following ultrasonic waves are applied:[11]~[14]The method for producing a toner for developing an electrostatic charge image according to any one of the above.
[0031]
  [16]The average particle size of the particles in the slurry is 3 μm or more and 9 μm or less,[11]~[15]The method for producing a toner for developing an electrostatic charge image according to any one of the above.
[0032]
  [17]The particles in the slurry have a sea-island structure,[11]~[16]The method for producing a toner for developing an electrostatic charge image according to any one of the above.
[0033]
  [18]An electrostatic charge image developing toner obtained by performing particle formation in an aqueous medium,[10]An electrostatic charge image produced using the production apparatus according to any one of the above, wherein the number of free release agent particles present on the surface of the toner particles is 3 or less per 100 toner particles. Development toner.
[0034]
  To form particles in an aqueous medium as described in [1] above, the toner particles are formed by forming resin particles or the like constituting the toner particles in an aqueous medium and aggregating the resin particles in the aqueous medium. Means to do.
  The edge portion formed by the straight line portion and the line segment adjacent to the straight line portion described in [1] above refers to a region indicated by 204 in FIG. That is, a region where both the extension lines intersect when the straight line portion 203 is extended and the line segment 202 adjacent to the straight line portion 203 is called an edge portion.
  The average particle diameter Dv50 of the toner particles described in [2] above is usually called 50% volume particle diameter or 50% volume average particle diameter, and is a median value of the volume average particle diameter of the toner particles. This is the value of the diameter. 50% volume particle size (Dv50) is the Coulter Counter TA- II It can be measured with a mold or a Coulter Multisizer (manufactured by Coulter).
[0035]
As described in [4] above, forming the wires by arranging them in parallel at a predetermined interval means that a screen is formed by arranging the wires at equal intervals, and any gaps (slits) formed between the wires are on the screen. This means that slits are formed so that the same value is obtained even in the portion.
[0036]
As described in [5] above, having a substantially triangular shape means that the cross-sectional shape of the wire used in the present invention is composed of three straight lines as shown in FIG. Means that the portion corresponding to the vertex of the triangle is made of a curved surface without having a vertex.
[0039]
  the above[6]The width of the slit of the screen described in (1) refers to a portion indicated by p in FIG.
[0040]
The impurities referred to in the present invention are the surfactant and dispersion stabilizer present in the aqueous medium used when the particles are produced, or the colorant particles and free release agents that have not been incorporated into the particles. In the present invention, it is possible to effectively remove these substances that adhere and remain on the surface of particles formed in an aqueous medium.
[0041]
Hereinafter, the present invention will be described in detail.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the production process of the toner for developing an electrostatic charge image has a step of allowing a toner dispersion containing solid particles obtained by forming particles in an aqueous medium to pass through a screen having a slit. To do.
[0043]
The toner dispersion in the present invention is a slurry-like liquid in which solid particles formed in an aqueous medium are dispersed in an aqueous medium. Specifically, a polymerizable monomer is polymerized in the aqueous medium. The liquid which disperse | distributed the solid particle obtained in the slurry form, and the liquid which melt | dissolved resin in the organic solvent and disperse | distribute the solid particle formed by distilling a solvent off in an aqueous medium is said.
[0044]
1 to 3 are schematic views of typical toner dispersion passing devices preferably used in the present invention.
[0045]
The toner dispersion liquid passing device 1 has a screen 2 through which the toner dispersion liquid passes, and the toner dispersion liquid is fed in the direction indicated by → in the drawing. The screen 2 has a gap (hereinafter also referred to as a slit), and the toner dispersion passes through the gap (slit) to remove impurities adhering to the toner particle surface. As described above, in the present invention, a toner dispersion containing solid particles obtained by forming particles in an aqueous medium is carried into the apparatus from the toner dispersion inlet 3 of the toner dispersion passage apparatus 1. Then, it passes through the slit 22 from above the screen surface 23 of the screen 2 and is discharged out of the apparatus through the toner dispersion outlet 4.
[0046]
In the toner dispersion passing device shown in FIG. 1, the disk-shaped flat screen shown in FIGS. 4B and 4C is arranged, and FIGS. 2 and 3 show the cylinder shown in FIG. A screen with a shape is arranged. The apparatus in FIG. 2 feeds the toner dispersion liquid from the outside to the inside of the cylindrical screen. The apparatus in FIG. 3 allows the toner dispersion liquid to pass from the inside to the outside of the cylindrical screen. Is.
[0047]
Next, the screen preferably used in the present invention will be described.
The screen that is disposed in the toner dispersion liquid passing device according to the present invention and allows the toner dispersion liquid to pass therethrough is configured with an interval through which the toner particles can pass through a bar-like or wire-like solid member (wire). In the screen according to the present invention, the solid members 21 are arranged at intervals so as to form a gap (slit) 22 through which the toner particles can pass. FIG. 4 shows a schematic diagram of a typical shape example of the screen according to the present invention. (A) is a cylindrical screen made by spiraling a wire like a coil spring, (b) and (c) are flat planar screens, and (b) is like a mosquito coil. It is a screen formed by processing a wire in a spiral shape. Further, (c) is a screen formed by arranging a plurality of linear solid members having different lengths at equal intervals. Further, the screen according to the present invention may be a screen in which ring-shaped wires having different diameters are concentrically arranged at equal intervals.
[0048]
Further, the solid material forming the screen according to the present invention has a cross-sectional shape having at least one straight line portion, and the screen surface is formed by the straight line portion in the cross-sectional shape. Here, the screen surface is a surface represented by reference numeral 23 in FIG. 1 and refers to a structural region of the screen through which the fed slurry first comes into contact. The slurry-like toner dispersion liquid fed into the toner dispersion passage device 1 according to the present invention is cleaned by removing impurities adhering to the surface of the toner particles when passing through the screen surface 23.
[0049]
As described above, the solid member forming the screen according to the present invention is characterized in that the cross-sectional shape thereof has at least one linear portion. For example, in the solid member 21 having a kamaboko-shaped (semi-circular) cross-sectional shape in FIG. 5A, the straight line portion refers to a region indicated by 203 in the cross-sectional portion 201. Reference numeral 202 denotes a line segment adjacent to the straight line portion. Reference numeral 204 denotes an edge portion formed between the straight line portion 203 and the line segment 202 adjacent to the straight line portion 203. FIG. 5 is a schematic diagram showing an example of the cross-sectional shape of the solid member constituting the screen according to the present invention, where (b) is a triangular shape, (c) is a trapezoidal shape, and (d) is an oval shape. is there.
[0050]
In addition, the solid member used by this invention should just have at least 1 linear part in the cross-sectional shape, and is limited to the solid member which has the cross-sectional shape shown to these (a)-(d). However, it has been confirmed that the cross-sectional shape shown in FIG. 5B has a substantially triangular shape is particularly preferable from the viewpoint of workability and the like. The end of the straight line portion 203 in the cross-sectional shape is preferably a curved surface, and may be a surface that does not form burrs (so-called C surface).
[0051]
Next, the passage of the toner dispersion liquid through the screen according to the present invention will be described.
[0052]
6A and 6B are schematic views showing the state of passage of the slurry-like toner dispersion liquid on the screen surface, where FIG. 6A is a triangular shape of the solid member 21 constituting the screen, and FIG. 6B is a kamaboko cross-sectional shape. It is a semi-circular shape of the mold. In FIG. 6, it is assumed that the toner dispersion is sent from the upper side to the lower side in the drawing.
[0053]
The arrow indicated by ↓ in the drawing represents the movement of the particles T in the toner dispersion liquid. In the screen according to the present invention, the slurry-like toner dispersion from the screen surface 23 side constituted by the linear portion 203 of the solid member 21 is shown. The liquid enters the gap (slit) 22 constituting the screen and passes through the slit 22, so that it is assumed that impurities remaining on the surface of the particles T are removed.
[0054]
As shown in FIG. 6, the toner particles T pass through the slit 22 on the screen surface 23, and then the individual particles T finally pass through the slit 22. In the toner dispersion liquid passing device according to the present invention, the toner particles T are accumulated and formed in the slits 22 having a width l larger than the toner particle diameter. This is the particle T made of the slurry-like toner dispersion liquid. However, when a passenger on a full train arrives at the station, it passes through the slit 22 while colliding with each other, as if rushing to the exit. It is presumed that the particles collide and collide, and as a result, the particles grind each other to remove impurities remaining on the particle surface. As described above, in the toner dispersion liquid passing device according to the present invention, while the slurry-like toner dispersion liquid passes through the slit 22 from the screen surface 23, the particles are sharpened in the aqueous medium and adhered to the particle surface. It is assumed that the remaining impurities are removed.
[0055]
In the screen according to the present invention, it is preferable that the wires, which are the solid members 21 constituting the screen, be arranged in parallel, that is, the wires are arranged at equal intervals. By arranging the wires at equal intervals, the gap (slit) between the wires becomes constant, which is preferable because there is no variation in the performance of passing particles on the screen surface. Further, by arranging the wires at equal intervals, the straight portion of the wire does not come into contact with the straight portion of the adjacent wire on the extension line. By arranging the wires at regular intervals so that the straight portions of the wires constituting the screen do not come into contact with each other in this way, the wires are always arranged at regular intervals, and the effect of sharpening particles between the slits is more exhibited. Guessed.
[0056]
The width of the slit constituting the screen according to the present invention is larger than the toner particle diameter, specifically 15 to 50 μm, preferably 20 to 40 μm. The slit width is a factor that controls the passage of particles and the collision between particles. That is, by setting the slit width to be somewhat narrow, it is possible to frequently cause collision between particles on the screen surface, and to effectively scrape off impurities adhering to the particle surface. At the same time, the slit width controls the particles to pass through the slit at an appropriate speed.
[0057]
In the present invention, when the slit width is less than 15 μm, the residence time of the toner particles on the screen surface becomes too long, and it takes a lot of time to pass through the slit. This is not preferable because there is a problem that the generated particles are destroyed too much.
[0058]
Also, if the slit width exceeds 50 μm, collision between particles is excessively reduced and impurities attached to the particle surface cannot be removed well, resulting in a toner with remaining impurities, and the effects found in the present invention can be obtained. This is not preferable because it cannot be reproduced.
[0059]
Further, the solid member 21 constituting the screen according to the present invention has edge portions 204 at both ends of the straight portion 203 of the cross section 201, that is, the straight portion 203 and the straight portion 203 in the cross section 201 of the solid member 21. It is preferable that the area between the line segment 202 adjacent to the surface is processed with a curved surface. Specifically, it is preferable that the value of the radius of curvature indicated by r in FIG. 6 described above at the end of the straight line portion 203 has a value in the range of 1 μm to 20 μm. In the present invention, when the end of the straight portion 203 is curved so that the radius of curvature is a value in the above range, the effect of sharpening the particles performed when the particles pass through the screen is efficiently exhibited. It has been confirmed.
[0060]
In the screen according to the present invention, the radius of curvature of the edge portion in the cross section 201 of the wire is 1 μm or more and 20 μm or less, particularly preferably when the value of the curvature radius is 2 μm or more and 12 μm or less. It is speculated that the effect of sharpening between them proceeds most efficiently.
[0061]
Further, it has been confirmed that if the curvature radius of the edge portion is not 1 μm, the edge is worn and stable performance cannot be obtained for a long time. On the other hand, if the radius of curvature exceeds 20 μm, the accumulation and retention of toner particles are promoted at the slit entrance on the screen surface, but the toner particles are strongly polished and tend to be crushed, which is not preferable.
[0062]
Further, when the value of the radius of curvature of the edge portion in the cross-sectional shape of the wire constituting the screen according to the present invention has a value of 0.25 to 5 times the average particle diameter Dv50 of the toner, the effect of the present invention is more clearly demonstrated. It has been confirmed that
[0063]
As described above, in the present invention, the stagnation time of particles in the slit is controlled by the curvature radius of the wire cross section, and when the curvature radius is large, the particles are effectively stagnation at the slit entrance to increase the number of collisions between the particles. When the radius of curvature is small, the particles can easily pass through the slits to control the passage of the toner particles through the slits.
[0064]
The radius of curvature referred to in the present invention is, for example, the limit of a curve or curved surface passing through three points as described in the Machine Glossary Dictionary edited by the Association for Practical Education and Training (published by Nikkan Kogyo Shimbun, first edition in 1997). When converted into a value, it is regarded as an arc, and the radius of the arc is called a radius of curvature, which means the reciprocal of the curvature. Incidentally, the curvature means the degree of bending of a curve or a curved surface. For example, when a point Q is taken very close to an arbitrary point P on the curve, and an angle formed by tangents at two points when Q is infinitely close to P. The ratio of the arc length between two points is expressed as a limit value. The calculation of these curvatures and radii of curvature for the subspaces of the Euclidean space based on mathematical principles can be referred to the description of curvature in the Iwanami Physics and Chemical Dictionary.
[0065]
In the present invention, when the edge portion between the straight line portion in the cross-sectional shape and the adjacent line segment forms a vertex, that is, when the edge portion is sharp, the surface area at the end of the slit is reduced, Not only is this not preferable because the effect of sharpening the particles decreases, but it is also confirmed that the particles are not preferable because they abut against the sharp apexes when passing through the screen surface, causing the particles to break or deteriorate.
[0066]
Further, in the screen 2 according to the present invention, the screen surface 23 is formed by the straight portion 203 in the cross section 201 of the solid member 21, so that the slurry-like toner dispersion does not remain on the screen 2 after passing through the slit 22. . FIG. 7 is a schematic diagram for explaining the influence of the shape of the screen surface on the slurry passage when the slurry is passed through the slit 22. FIG. 7A shows a screen in which the screen surface 23 according to the present invention is configured by a straight portion 203, and FIG. 7B shows a screen surface 23 having a configuration outside the present invention other than the straight portion 203 of the solid member 21. This is a screen composed of areas. Arrow ↓ represents the passing direction of the slurry (particle T).
[0067]
In the screen of FIG. 7A, since there is no region for capturing and holding the particles T that have passed through the screen surface 23 in the slit 22, the particles T that have passed through the screen surface 23 can move smoothly. The particles T do not remain.
[0068]
On the other hand, in the screen of FIG. 7B, the particles T are deposited on the screen surface 23 in the region other than the linear portion 203 of the solid member 21 and stagnate, and then held on the solid member 21 without passing through the slit 22. There are stagnant particles T. In this way, some particles that have passed through the screen surface 23 are not preferable because they remain on the screen 2 without passing through the slit 22.
[0069]
The solid member material constituting the screen according to the present invention is not particularly limited as long as it does not have the property of modifying the toner dispersion, but from the viewpoint of durability, corrosion resistance, and workability, for example, the wire Those composed of such linear materials are preferred. In a screen in which wires are installed at a predetermined interval, the slits described above correspond to gaps formed between the installed wires, and the slurry containing toner particles passes through the gaps between the wires. Impurities attached to the substrate are removed.
[0070]
The material constituting the solid member such as a wire forming the screen according to the present invention is a material having a certain degree of rigidity, corrosion resistance, and good workability because the screen allows the slurry to pass continuously and at high speed. Specifically, metal materials such as stainless steel, nickel, titanium, zirconium and molybdenum, and organic materials such as Kevlar are preferable. In the present invention, a nickel alloy wire having a nickel content of 25% or more is particularly preferable. Further, the solid material forming the screen is not limited to the wire, and it has been confirmed that the effect of the present invention can be found even when, for example, a metal plate is subjected to an etching process and slits are arranged at a constant gap. .
[0071]
In the present invention, when a nickel alloy is used as the constituent material of the screen as described above, the reason is not clear, but a toner image with stable gradation can be obtained, and the continuous image exceeding 500,000 sheets in a high temperature and high humidity environment. It has been confirmed that a stable toner image can be obtained even after copying.
[0072]
The thickness (diameter) of the wire forming the screen according to the present invention is not particularly limited, and the slit width can be arranged at equal intervals with high accuracy, and an effective slurry passage can be achieved. Any material can be used.
[0073]
In the toner dispersion passing device according to the present invention, impurities can be effectively removed from the surface of the toner particles when the slurry passing speed when passing the slurry through the screen is 12.5 to 167 cm / min. It has been confirmed that not only is it possible, but also retention of toner particles on the screen surface can be appropriately controlled. If the passing speed of the slurry greatly exceeds 167 cm / min, the toner is crushed and toner fine powder is generated, which is not preferable. On the other hand, if the passing speed is less than 12.5 cm / min, the charging stability is reduced, and the effect of the present invention cannot be reproduced.
[0074]
The passing speed of the slurry when passing through the screen of the toner dispersion passing device according to the present invention is to measure the moving speed of the slurry, and can be measured using a generally known flow rate measuring device. .
[0075]
As a specific example, for example, the toner dispersion liquid passing device shown in FIG. 2 is used, and an average value of flow velocities at three locations, upper screen surface s, screen surface center t, and screen surface lower u, is used.
[0076]
The flow rate is measured with a three-dimensional current meter manufactured by Chuo Kousakusha at the above three points after at least one minute has passed in a state where the slurry is passed through the screen surface. The flow velocity value is the combined value obtained by the following formula.
[0077]
V = (Vs²+ Vt²+ Vu²)^0.5
V: Composite value
Vs: Flow velocity value above the screen surface
Vt: Flow velocity value at the center of the screen surface
Vu: Flow velocity value below the screen
Further, in the present invention, in addition to the method for obtaining the moving speed of the slurry on the screen surface as described above, the moving amount of the slurry per unit time on the screen surface can be calculated from the supply amount of the slurry per unit time. it can.
[0078]
In the toner dispersion passing device according to the present invention, the screen has a frequency of 10 to 38 kHz and a power density of 0.01 to 0.5 W · cm.^-2When ultrasonic waves are applied and the slurry is passed while applying vibrations generated by the ultrasonic waves, the vibrations from the ultrasonic waves act on the toner particles staying on the screen surface. As a result, the particles collide with each other. It was confirmed that the vibration from the ultrasonic wave promotes the sharpening of the particles when the particles are sharpened with each other, and the removal of impurities from the toner particle surface can be achieved in a short time.
[0079]
Here, the power density means the amount of work per unit area on the working surface when the work surface is subjected to work or energy is applied using waves such as laser light or ultrasonic waves. , Ultrasonic power density W · cm^-2Use units.
[0080]
As an ultrasonic oscillator used in the present invention, a frequency of 10 kHz to 38 kHz, 0.01 W · cm^-20.5W · cm^-2As long as it can output the following power density, a known ultrasonic transmitter may be used. ) Etc. are used.
[0081]
The ultrasonic wave applied to the screen according to the present invention may be applied continuously or repeatedly, but the power density is 0.5 W · cm.^-2If the application is performed at a level that greatly exceeds the above, a strong vibration is imparted to the particles staying on the slurry surface, which may cause the particles to be crushed and cause generation of fine powder.
[0082]
As described above, the toner dispersion liquid passing device according to the present invention passes through the slits existing between the wires from the screen surface formed by the straight section of the wire cross section constituting the screen when the slurry passes through the screen. Thus, the particles are appropriately stagnated on the screen surface at the entrance of the slit and the particles collide with each other to sharpen the particles and perform cleaning.
[0083]
Further, the wire used in the present invention allows the toner particles to smoothly pass through the slit when the toner particles are passed through the slit by applying a curved surface process to the edge portion formed by the straight portion and the adjacent portion of the wire cross section. At the same time, it has the effect of promoting the collision between the particles by appropriately stagnating the particles on the screen surface at the entrance of the slit.
[0084]
In the present invention, the slurry that has been passed through the slit may be dispersed again in the cleaning liquid to thoroughly wash the particles, and then the operation of passing the slit again may be repeated.
[0085]
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. 8, the resin constituting the particles and the components of the crystalline substance and the colorant as 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. 8 have a structure in which a crystalline substance island A and a colorant component island B constituting the release agent exist in the continuous phase (sea) of the 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 The toner particle structure here means the structure of the particles in the slurry according to the present invention.
[0086]
Next, the particle diameter of the toner of the present invention will be described. The toner used in the present invention has an average particle size 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. The particle diameter of the toner here means the average particle diameter of the particles in the slurry according to the present invention. Here, the average particle diameter is generally known and means, for example, a number average particle diameter or a volume average particle diameter.
[0087]
When the 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 number average particle size are performed using a Coulter Counter TA-II, Coulter Multisizer (both manufactured by Coulter), SLAD1100 (a laser diffraction 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.
[0088]
Next, a toner manufacturing method according to the present invention will be described.
The toner according to the present invention is produced through particle formation in an aqueous medium. Performing particle formation in an aqueous medium means forming resin particles and colored particles constituting toner particles in an aqueous medium, and aggregating the resin particles to form particles. That is, at least a polymerizable monomer is polymerized in an aqueous medium, and the obtained polymer may be aggregated, but this production method is performed by polymerizing a polymerizable monomer by a suspension polymerization method. To prepare resin particles, or to make fine resin particles by emulsion polymerization of the monomer or mini-emulsion polymerization in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added. In addition, the charge controllable resin particles are added as necessary, and then the resin particles are aggregated and fused by adding an organic solvent, an aggregating agent such as a salt, and the like.
<Suspension polymerization method>
As an example of a method for producing the toner of the present invention, a charge control resin is dissolved in a polymerizable monomer, and various constituent materials such as a colorant, a mold release agent, and a polymerization initiator are added. Then, various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets of a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction device (stirring device) which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention. In the present invention, the “aqueous medium” refers to a medium containing at least 50% by mass of water.
<Emulsion polymerization method>
Further, as a method for producing the toner of the present invention, a method in which resin particles are prepared by salting out / fusion in an aqueous medium can also be mentioned. This method is not particularly limited, and examples thereof include methods described in JP-A Nos. 5-265252, 6-329947, and 9-15904. 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, the toner of 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.
[0089]
In the method for producing a toner of the present invention, particles are formed by fine particles of composite resin and colorant particles formed through a step of polymerizing a polymerizable monomer after dissolving a crystalline substance in at least a polymerizable monomer. Is obtained. The toner of the present invention dissolves a crystalline substance in a polymerizable monomer, but it may be dissolved and dissolved or melted and dissolved.
[0090]
In addition, the toner production method of the present invention is preferably one in which particles are formed from composite resin fine particles obtained by a multistage polymerization method and colorant particles. The multistage polymerization method will be described below.
<Method for producing composite resin particles obtained by multistage polymerization method>
The toner production method of the present invention is preferably composed of the following steps.
[0091]
1: Multistage polymerization process
2: A salting out / fusing step for obtaining toner particles by salting out / fusing the composite resin particles and the colorant particles.
3: Filtration / washing step of separating the toner particles from the toner particle dispersion and removing the surfactant from the toner particles.
4: a drying process for drying the washed toner particles;
5: Step of adding an external additive to the dried toner particles
Consists of
[0092]
Hereinafter, each step will be described in detail.
[Multistage polymerization process]
The multi-stage polymerization step is a polymerization method performed for expanding the molecular weight distribution of the resin particles so as to obtain a toner in which offset generation is prevented. That is, in order to form phases having different molecular weight distribution in one resin particle, the polymerization reaction is performed in multiple stages, and the obtained resin particle has a molecular weight gradient from the center of the particle toward the surface layer. It is intended to be formed. 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.
[0093]
In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoint of production stability and crushing strength of the resulting toner. Hereinafter, the two-stage polymerization method and the three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described. The toner obtained by such a multistage polymerization reaction preferably has a lower molecular weight as the surface layer from the viewpoint of crushing strength.
[0094]
<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 containing a crystalline substance and an outer layer (shell) formed from a low molecular weight resin. is there.
[0095]
This method will be described in detail. First, a crystalline substance is dissolved in a monomer to prepare a monomer solution, and the monomer solution is added to oil droplets in an aqueous medium (for example, a surfactant aqueous solution). After the dispersion, this system is polymerized (first stage polymerization) to prepare a dispersion of high molecular weight resin particles containing a crystalline substance.
[0096]
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.
[0097]
<Three-stage polymerization method>
The three-stage polymerization method produces composite resin particles composed of a central part (core) formed from a high molecular weight resin, an intermediate layer containing a crystalline substance, and an outer layer (shell) formed from a low molecular weight resin. Is the method. The toner of the present invention exists as the composite resin particles as described above.
[0098]
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). In the aqueous medium, a monomer solution obtained by dissolving a crystalline substance in a monomer is dispersed in oil droplets, and then this system is polymerized (second-stage polymerization) to obtain resin particles (cores). A coating layer (intermediate layer) made of a resin (monomer polymer) containing a crystalline substance is formed on the surface of the particles, and a dispersion of composite resin particles (high molecular weight resin-intermediate molecular weight resin) is prepared. Prepare.
[0099]
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, the incorporation of the intermediate layer is preferable because the crystalline substance can be finely and uniformly dispersed.
[0100]
One feature of the toner production method according to the present invention is that the polymerizable monomer is polymerized in an aqueous medium. That is, when forming resin particles (core particles) or a coating layer (intermediate layer) containing a crystalline substance, the crystalline substance is dissolved in the monomer, and the resulting monomer solution is oiled in an aqueous medium. It is a method of obtaining latex particles by dispersing in drops and adding a polymerization initiator to this system for polymerization treatment.
[0101]
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.
[0102]
As a suitable polymerization method for forming resin particles or a coating layer containing a crystalline substance, the crystalline substance is a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. The monomer solution dissolved in is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the resulting dispersion to cause radical polymerization in the oil droplets. A method (hereinafter referred to as “mini-emulsion method” in the present invention), and the effects of the present invention can be exhibited more preferably. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.
[0103]
According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, the crystalline substance dissolved in the oil phase has little detachment and is sufficient in the formed resin particles or coating layer. Any amount of crystalline material can be introduced.
[0104]
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. Here, by giving a distribution to the dispersed particle diameter, the phase separation structure of the crystalline substance in the toner particles, that is, the ferret diameter, the shape factor, and the coefficient of variation thereof may be controlled.
[0105]
In addition, as other polymerization methods for forming resin particles or a coating layer containing a crystalline substance, known methods such as an emulsion polymerization method, a suspension polymerization method, and a seed polymerization method can be employed. These polymerization methods can also be employed to obtain resin particles (core particles) or coating layers constituting the composite resin particles that do not contain a crystalline substance.
[0106]
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.
[0107]
Moreover, it is preferable that the glass transition temperature (Tg) of a composite resin particle exists in the range of 48-74 degreeC, More preferably, it is 52-64 degreeC.
[0108]
The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C. The toner produced in the present invention 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, etc. Explained.
[Particle formation process]
In this particle forming step, the composite resin particles obtained by the multistage polymerization step are aggregated and fused with colorant particles or composite resin particles, and these particles are fused together to form an irregular (non-spherical) toner particle. It is the process of obtaining. In this step, the particles are aggregated and fused by the salting out / fusion method in which aggregation and fusion are simultaneously performed, as described below, after completion of aggregation by salting out at a temperature below the glass transition point. Examples thereof include a method of fusing the aggregated particles by heat and a method of aggregating using heat or an organic solvent. Hereinafter, the salting out / fusion method will be described.
[0109]
The salting-out / fusion described above means that salting-out (aggregation of particles) and fusion (disappearance of the interface between particles) occur at the same time, or an 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 (composite resin particles, colorant particles) under a temperature condition higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .
[0110]
In this particle formation step by salting out / fusion, internal additive particles such as charge control agents (fine particles having a number average primary particle size of about 10 to 1000 nm) are salted out / fused together with composite resin particles and colorant particles. You may let them.
[Aging process]
The aging step is a step subsequent to the particle formation step, and the temperature is kept near the melting point of the crystalline substance, preferably the melting point ± 20 ° C., even after the resin particles are fused, and stirring is continued at a constant strength. This is a step of phase-separating the crystalline substance. In this step, it is possible to control the ferret diameter, shape factor, and variation coefficient of the crystalline material.
[Concentration / washing process]
This concentration / washing step removes impurity particles such as free release agents and colored particles from the toner particle surface obtained in the particle formation step from the toner particle surface, and in the dispersion (slurry) containing the toner particles. The aqueous medium is removed and the slurry is concentrated. Then, the concentrated slurry is redispersed in the cleaning liquid again to remove deposits such as a surfactant and a salting-out agent from the toner particles. As described above, the present invention allows the slurry to pass through the slit of the toner dispersion passage device described above in this step and removes the impurity particles from the surface of the toner particles without changing the charging property of the generated particles. In addition, effective impurity removal from the particle surface is achieved without damaging or breaking the particle. In the present invention, the slurry once passed through the slit is poured into the washing water, diluted, washed, and then the slurry is again passed through the slit to remove impurities, thereby reliably removing impurities from the particle surface. The operation may be performed.
[0111]
In this manner, after repeating the concentration and washing of the slurry, a wet cake (cake-like particle aggregate) having a particle ratio of around 50% is obtained.
[Drying process]
This step is a step of drying the toner particles separated from the concentrated slurry.
[0112]
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.
[0113]
The water content of the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.
[0114]
In addition, when the toner particles that have been dried are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
[0115]
The toner of the present invention forms composite resin particles in the absence of a colorant, adds a dispersion of colorant particles to the dispersion of the composite resin particles, and aggregates and melts the composite resin particles and the colorant particles. It is preferable to prepare it by forming particles.
[0116]
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.
(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.
[0117]
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.
[0118]
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.
[0119]
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.
[0120]
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.
[0121]
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.
(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.
(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).
[0122]
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.
[0123]
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.
(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.
[0124]
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.
[0125]
(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.
[0126]
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.
[0127]
Examples of N, N-diallyl-alkylamine in (d) include N, N-diallylmethylammonium chloride, N, N-diallylethylammonium chloride and the like.
[0128]
(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.
[0129]
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).
[0130]
(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, and for example, compounds having a mercapto group such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, and 3-propionic acid n-octyl ester are used.
[0131]
(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.
[0132]
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).
[0133]
In the present invention, surfactants represented by the following general formulas (1) and (2) are particularly preferably used.
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.
[0134]
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 R¹Examples 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.
[0135]
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.
[0136]
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.
[0137]
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.
[0138]
Specific examples of the surfactant represented by the general formulas (1) and (2) are shown below, but the present invention is not limited thereto.
[0139]
Compound (101): C_TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeNa
Compound (102): C_TenH_{twenty one}(OCH₂CH₂)_ThreeOSO_ThreeNa
Compound (103): C_TenH_{twenty one}(OCH₂CH₂)₂SO_ThreeNa
Compound (104): C_TenH_{twenty one}(OCH₂CH₂)_ThreeSO_ThreeNa
Compound (105): C₈H₁₇(OCH₂CH (CH_Three))₂OSO_ThreeNa
Compound (106): C₁₈H₃₇(OCH₂CH₂)₂OSO_ThreeNa
In the present invention, from the viewpoint of maintaining the charge holding function of the toner in a good state, suppressing fog generation under high temperature and high humidity, and improving transferability, and suppressing the increase in charge amount under low temperature and low humidity, From the viewpoint of stabilizing the amount, the content of the surfactant represented by the general formulas (1) and (2) in the toner for developing an electrostatic charge image is preferably 1 to 1000 ppm, more preferably 5 It is -500 ppm, Most preferably, it is 7-100 ppm.
[0140]
In the present invention, by setting the amount of the surfactant to be contained in the toner within the above described range, the chargeability of the electrostatic image developing toner of the present invention is always uniform without being influenced by environmental influences. It can be applied and maintained in a stable state.
[0141]
Further, the content of the surfactant represented by the above general formulas (1) and (2) contained in the toner for developing an electrostatic charge image of the present invention is calculated by the following method.
[0142]
1 g of toner is dissolved in 50 ml of chloroform, and the surfactant is extracted from the chloroform layer with 100 ml of ion exchange water. Further, the extracted chloroform layer is extracted once again with 100 ml of ion-exchanged water to obtain a total of 200 ml of extract (water layer), and this extract is diluted to 500 ml.
[0143]
Using this diluted solution as a test solution, in accordance with the method defined in JIS 33636, color was developed with methylene blue, the absorbance was measured, and the surfactant content in the toner was measured from a separately prepared calibration curve. is there.
[0144]
Moreover, the structure of the surfactant represented by the general formulas (1) and (2) was determined by analyzing the above extract using 1H-NMR.
[0145]
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.
[0146]
In the present invention, a nonionic surfactant can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, Examples include higher fatty acid and polyethylene glycol esters, higher fatty acid and polypropylene oxide esters, and sorbitan esters.
[0147]
In the present invention, these surfactants are mainly used as an emulsifier during emulsion polymerization, but may be used for other steps or for other purposes.
[0148]
(Molecular weight distribution of resin particles and toner)
The toner of the present invention 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. It is preferable that it exists in 1,000-1,000,000, 25,000-150,000, and 1,000-50,000.
[0149]
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.
[0150]
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 at room temperature using a magnetic stirrer or the like. 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 measuring 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.
[0151]
(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.
[0152]
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.
[0153]
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.
[0154]
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.
[0155]
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.
[0156]
In the present invention, the metal salt concentration may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.
[0157]
(Coloring agent)
The toner of the present invention is obtained by particle formation of the above composite resin particles and colorant particles. As the colorant (colorant particles used for particle formation with the composite resin particles) constituting the toner of the present invention, organic pigments are usually preferably used as described above, but various inorganic pigments other than organic pigments and Dyes are also used, and are not necessarily limited to organic pigments.
[0158]
As the inorganic pigment, conventionally known pigments can be used. As specific inorganic pigments, black pigments include, for example, carbon black such as furnace black, channel black, acetylene black, thermal black, lamp black, and the like. Magnetic powders such as magnetite and ferrite may also be used.
[0159]
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.
[0160]
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. These inorganic pigments may be used in the form of a water-wet colorant paste.
[0161]
Conventionally known organic pigments and dyes can be used, and specific organic pigments are exemplified below.
[0162]
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.
[0163]
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.
[0164]
Examples of green or cyan pigments 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.
[0165]
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.
[0166]
These organic pigments and dyes 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 it is 3-15 mass%.
[0167]
(Crystalline substance)
The toner used in the present invention forms a sea-island structure by fusing resin particles containing a crystalline substance constituting a release agent regime in an aqueous medium and appropriately aggregating the crystalline substance in an aging process. It is preferable that the toner be a toner. In this way, by forming resin particles containing a crystalline substance in resin particles in an aqueous medium with colorant particles, a toner in which the crystalline substance 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 crystalline substance ± 20 ° C. even after the resin particles are fused.
[0168]
In the toner of the present invention, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene and the like are preferable as the crystalline substance having a releasing function, and particularly preferably an ester compound represented by the following formula: is there.
[0169]
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.
[0170]
Next, the example of a typical compound is shown below.
[0171]
[Chemical 1]

[0172]
[Chemical 2]

[0173]
In the present invention, crystalline polyester can also be used as the crystalline substance. As the crystalline polyester, aliphatic diol and aliphatic dicarboxylic acid (including acid anhydride and acid chloride) are used. Polyester obtained by reaction is preferred.
[0174]
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.
[0175]
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, acid anhydrides or acid chlorides thereof Can be mentioned.
[0176]
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 with adipic acid.
[0177]
The amount of the compound added is 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass with respect to the whole toner.
[0178]
(Developer)
The toner of the present invention may be used as a one-component developer or a two-component developer. When used as a one-component developer, the non-magnetic one-component developer or about 0.1 to 0.5 μm in the toner is used. Examples thereof include a magnetic one-component developer containing magnetic particles.
[0179]
It can also be mixed with a carrier and used as a two-component developer. In this case, as magnetic particles of the carrier, metals such as iron, ferrite and magnetite, alloys of these metals with metals such as aluminum and lead, etc. Conventionally known materials can be used. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
[0180]
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.
[0181]
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.
[0182]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the text, “part” means “part by mass”.
Toner dispersion adjustment
Toner dispersion 1
Production example of resin particles for toner
[Latex 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
(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.
[0183]
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). And a latex (a dispersion of resin particles made of a high molecular weight resin) was prepared. This is referred to as “latex (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 a compound represented by the above formula 19) (hereinafter referred to as “Exemplary Compound (19)”) was added, heated to 90 ° C. and dissolved to prepare a monomer solution. .
[0184]
On the other hand, a surfactant solution obtained by dissolving 1.6 g of an anionic surfactant (the above formula (101)) in 2700 ml of ion-exchanged water is heated to 98 ° C., and a dispersion of core particles is added to the surfactant solution. After adding 28 g of the latex (1H) in terms of solid content, the compound (19) of the exemplified compound (19) was simply added by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. The monomer solution was mixed and dispersed for 8 hours to prepare a dispersion (emulsion) containing emulsified particles (oil droplets).
[0185]
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 performed by heating and stirring for 12 hours to obtain latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin was covered with an intermediate molecular weight resin). This is referred to as “latex (1HM)”.
[0186]
When the latex (1HM) was 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 obtained by dissolving 7.4 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water is added to the latex (1HM) obtained as described above, and 300 g of styrene under a temperature condition of 80 ° C. A monomer mixture composed of 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and latex (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 molecular weight resin and containing the exemplified compound (19) in the intermediate layer. This latex is referred to as “latex (1HML)”.
[0187]
The composite resin particles constituting the latex (1HML) had peak molecular weights of 138,000, 80,000 and 13,000, and the weight average particle size of the composite resin particles was 122 nm.
[Toner dispersion 1]
Anionic surfactant (sodium dodecyl sulfate) 59.0 g was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring this solution, 420.0 g of carbon black was gradually added, and then “Clearmix” (M Technique) A dispersion of colorant particles was prepared by performing a dispersion treatment using a product manufactured by Co., Ltd.
[0188]
A reaction vessel (four-necked flask) equipped with 420.7 g of latex (1HML) (in terms of solid content), 900 g of ion-exchanged water, and 166 g of a colorant dispersion, and a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device. ) And stirred. After adjusting the temperature in the container to 30 ° C., 5 mol / L sodium hydroxide aqueous solution was added to this solution to adjust the pH to 8.
[0189]
Next, an aqueous solution obtained by dissolving 12.1 g of magnesium chloride hexahydrate in 1000 ml of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, the temperature was started to rise, and the system was heated to 90 ° C. over 6 to 60 minutes to produce associated particles. In this state, the particle diameter of the associated particles was measured with “Coulter Counter TA-II”. When the number average particle diameter reached 6.4 μm, an aqueous solution in which 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. Was added to stop particle growth, and as a ripening treatment, the mixture was heated and stirred at a liquid temperature of 98 ° C. for 2 hours to complete the particle fusion.
[0190]
Thereafter, the mixture was cooled to 30 ° C., hydrochloric acid was added to adjust the pH to 4.5, and a toner dispersion was obtained. The obtained toner dispersion is designated as Toner Dispersion 1.
[Toner dispersion 2]
Toner dispersion 2 was obtained in the same manner as in the preparation of toner dispersion 1, except that an aqueous sodium chloride solution was added when the associated particles grew to 4.3 μm.
[Toner dispersion 3]
165 g of styrene, 35 g of n-butyl acrylate, 10 g of carbon black, 2 g of di-t-butylsalicylic acid metal compound, 8 g of styrene-methacrylic acid copolymer and 20 g of paraffin wax (mp = 90 ° C.) are heated to 60 ° C. It was uniformly dissolved and dispersed at 12,000 rpm with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). To this, 10 g of 2,2′-azobis (2,4-valeronitrile) as a polymerization initiator was added and dissolved to prepare a polymerizable monomer composition.
[0191]
Next, 450 g of 0.1 M sodium phosphate aqueous solution was added to 710 g of ion exchange water, and 68 g of 1.0 M calcium chloride was gradually added while stirring at 13,000 rpm with a TK homomixer to prepare a suspension in which tricalcium phosphate was dispersed. did. The above polymerizable monomer composition is added to this suspension and stirred at 10,000 rpm for 20 minutes with a TK homomixer to granulate the polymerizable monomer composition, and then the tricalcium phosphate is dissolved with hydrochloric acid. Removal of toner dispersion 3 was obtained. The volume average sectional particle diameter Dv50 of the toner in the toner dispersion liquid 3 is 7.2 μm.
[Toner dispersion 4]
30 parts by mass of the exemplified compound (19) was dissolved by heating in 250 parts by mass of ethyl acetate, and then rapidly cooled and precipitated with liquid nitrogen to obtain a release agent ethyl acetate dispersion. The average particle size of the release agent was 0.6 μm as measured by a laser diffraction / scattering particle size distribution analyzer LA-700 (manufactured by Horiba, Ltd.). 100 parts by mass of a polyester resin (Mw: 20000, Tg: 66 ° C., Tm: 106 ° C.) consisting of a bisphenol A propylene oxide adduct, a bisphenol A ethylene oxide adduct, and a terephthalic acid derivative, 8 parts by mass of carbon black, ethyl acetate 80 parts by mass was mixed and dispersed in a ball mill for 10 hours, and then 36 parts by mass of the ethyl acetate dispersion of Exemplified Compound (19) was added and stirred well until uniform. This liquid is called A liquid.
[0192]
On the other hand, 60 parts by mass of calcium carbonate and 40 parts by mass of water were mixed and dispersed in a ball mill for 10 hours, and then 7 parts by mass of a calcium carbonate dispersion and 100 parts by mass of a 2% aqueous solution of Serogen BS-H (Daiichi Kogyo Seiyaku Co., Ltd.). Was placed in a cooking mixer MX-915C (manufactured by Matsushita Electric Industrial Co., Ltd.) and stirred for 5 minutes. This liquid is designated as B liquid.
[0193]
Using a stirrer, 50 parts by mass of the B liquid and 50 parts by mass of the A liquid were stirred and mixed to obtain a suspension. Thereafter, the solvent was removed under reduced pressure. Next, 100 parts by mass of 6 mol / L hydrochloric acid was added to dissolve and remove calcium carbonate, whereby a toner dispersion 4 was obtained. The volume average cross-sectional particle diameter Dv50 of the toner in the toner dispersion 4 is 5.1 μm.
[Screen adjustment and screen passing process]
Screens 1 to 8 shown in Table 1 were prepared. Each screen is obtained by changing the slit width (wire gap) of the screen, the cross-sectional shape of the wire, the radius of curvature of the edge, and the material conditions. Also, comparative screens 2 and 3 used in Comparative Example 2 and Comparative Example 3 described later were prepared. The screen was installed in the screen fixing device shown in FIGS.
[0194]
The diameter of the wire constituting the screen is 70 μm.
Moreover, Incoloy 855 (JISG4901, 4902, 4903, 4904) was used for the nickel alloy constituting the wire, and SUS316 was used for the stainless steel (SUS).
[0195]
[Table 1]

[0196]
The above-described screens 1 to 8 are loaded into the toner dispersion passage device shown in FIGS. 1 to 3, and the above-mentioned toner dispersion is allowed to pass through. As shown in Table 2, comparison is made with toners 1 to 16 according to the invention. Toners 1 to 4 were produced.
[0197]
Toners 1 to 14 and comparative toners 2 and 3 were obtained by loading a cylindrical dispersion screen into the toner dispersion liquid passing device shown in FIG. The toner 15 is obtained by loading the toner dispersion liquid passing device shown in FIG. 3 and passing the toner dispersion liquid. The toner 16 has the screen 1 made flat and the toner dispersion passing device shown in FIG. Obtained by loading.
[0198]
In each toner dispersion liquid, a wire constituting the screen forms a screen surface with a straight line portion in a cross-sectional shape, and the toner dispersion liquid is passed through the screen surface to which the straight line portion faces.
[0199]
In addition, as a comparative example, in the toner dispersion liquid passing device of FIG. 3, the screen that did not pass through the screen is Comparative Example 1, and the screen surface is the opposite side of the surface of the screen 5 where the straight line portion is facing. The sample loaded and passed through the toner dispersion was designated as Comparative Example 4.
[0200]
In the case of using a drain, when the liquid was fed for 4 hours, a liquid feeding stop time of 2 hours was provided, and unnecessary residue in the screen fixing device was discharged.
[Solid-liquid separation process, drying process, and external additive mixing process]
Each toner dispersion that has passed through the screen is repeatedly washed with ion exchange water at 45 ° C. using a centrifugal filtration device provided with a filter cloth, and then dried with hot air at 40 ° C., and then the hydrophobic silica 1 By mixing with mass%, toners 1 to 16 having the combinations shown in Table 2 were obtained. Also, comparative toners 1 to 4 were obtained by the following procedure.
Toner for comparison 1
Toner dispersion liquid 1 was subjected to solid-liquid separation without passing through a screen passing step, dried, and hydrophobic silica was added and mixed so as to be 1% by mass to obtain comparative toner 1.
Comparative toner 2-4
After passing the toner dispersion 1 through a screen shown in Table 1, solid-liquid separation, drying, and addition and mixing were carried out so as to obtain 1% by mass of hydrophobic silica, whereby Comparative toners 2 to 4 were obtained. In the comparative toners 2 and 3, as shown in Table 1, the cross-sectional shape of the wire is a circle, and the cross-sectional shape does not have a linear portion.
[0201]
Further, the comparative toner 4 was placed in the toner dispersion passing device of FIG. 2 with the screen 5 used when manufacturing the toner 5 turned upside down. That is, the cross-sectional shape of the wire has a straight portion, but the toner dispersion was fed from the opposite side of the surface having the straight portion.
[0202]
In Comparative toners 2 to 4, since the screen was clogged, the liquid feeding was stopped and the cleaning was continued manually. However, the productivity was extremely low. Table 2 shows toners 1 to 16 and comparative toners 1 to 4.
[0203]
Further, the state of impurity adhesion on the surface of 100 toner particles generated by a transmission electron microscope was confirmed. The results are shown in Table 2. In Table 2, the volume average particle diameter of the toner particles was measured by Coulter Counter TA-II, and the amount of impurities attached per 100 particles was evaluated by a transmission electron micrograph.
[0204]
Further, the toner dispersion passing speed in Table 2 is measured using the above-mentioned three-dimensional velocimeter manufactured by Chuo Kousakusha. When the flat screen shown in FIG. 1 is used, the center point of the screen is measured. The average flow velocity was obtained from the flow velocity at the outer edge of the screen and at the center point and the middle point of the outer edge.
[0205]
Furthermore, in this example, ultrasonic waves were applied using a magnetostrictive nickel vibrator ultrasonic generator manufactured by Ultrasonic Industry Co., Ltd., and the slurry passed through the screen.
[0206]
[Table 2]

[0207]
Next, each of the toners 1 to 16 according to the present invention and the comparative toners 1 to 4 are mixed with a ferrite carrier having a volume average particle diameter of 60 μm so that the toner concentration becomes 6%. Developers 1 to 16 and comparative developers 1 to 4 as system developers were obtained, and were designated as Examples 1 to 16 and Comparative Examples 1 to 4, respectively.
[0208]
[Table 3]

[0209]
Live-action evaluation
Each developer was set in a commercially available digital copying machine Sitoos 7035 (manufactured by Konica Corporation), continuous copying was performed for 750,000 sheets, and the following items were evaluated for copy images after 750,000 sheets. As a copy image, a character original having an A4 size blackening area ratio of 5% was used, and a printed copy was made on an A4 transfer paper at an equal magnification.
[0210]
Evaluation was carried out in an ultra-high humidity environment (30 ° C., 90% RH).
(1) Change in charge amount over time
The charge amount when the developer was set and the first image was output was Qa, and the charge amount when 750,000 images were output was Qb, and the ratio Qb / Qa between them was evaluated.
[0211]
: Qb / Qa value is 0.9 or more and less than 1.1
○: Qb / Qa value is 0.8 or more and less than 0.9 or 1.1 or more and less than 1.2
Δ: Qb / Qa value is 0.7 or more and less than 0.8 or 1.2 or more and less than 1.3
X: The value of Qb / Qa is less than 0.7 or 1.3 or more
It was.
(2) Early fogging
In the initial stage, a white background image was printed, and the relative density with respect to the transfer paper was measured with a Konica densitometer (manufactured by Konica). The evaluation criteria were as follows.
[0212]
◎: 0.000 or more and less than 0.002
○: 0.002 or more and less than 0.004
Δ: 0.004 or more and less than 0.009
×: 0.009 or more
(3) Tonal variation
A patch image having an initial relative density of 0.3 to 0.4 was formed and evaluated by a density change ΔD after 750,000 copies.
[0213]
A: ΔD = 0.000 or more and less than 0.003
○: ΔD = 0.003 or more and less than 0.006
Δ: ΔD = 0.006 or more and less than 0.01
×: ΔD = 0.01 or more
The results are shown in Table 4.
[0214]
[Table 4]

[0215]
As is clear from the results of Table 4, the electrostatic image developing toner obtained through the production method according to the present invention has a stable charging property with time and hardly generates fog in the initial stage. It was confirmed that a toner image having a good and stable image quality with little gradation variation can be obtained.
[0216]
In particular, it was confirmed that the toner obtained by the production method according to the present invention can provide a stable toner image even under a severe environment such as an ultra-high humidity environment of 30 ° C. and 90% RH. This is because the use environment of the toner for developing an electrostatic charge image that is guaranteed by a conventional electrophotographic apparatus manufacturer is more severe than the range of 10 ° C., 20% RH to 30 ° C., 80% RH. It was confirmed that the electrostatic charge image developing toner obtained by the above method can exhibit good performance.
[0217]
In addition, in this invention, after carrying out a present Example, when 1.5 million sheets, 4.5 million sheets, and 7.5 million sheets were continuously copied and the said evaluation was performed, it was confirmed that a favorable result is obtained in all. .
[0218]
【The invention's effect】
As is clear from the results of the examples, the toner particles obtained through the process of passing the slurry through the slits by the production apparatus according to the present invention have no impurities remaining on the surface of the toner particles. It was confirmed that the charge amount on the surface of the toner particles did not change even when long-term continuous image formation was performed in an environment exceeding several hundred thousand sheets.
[0219]
Further, in the image formation using the toner particles obtained by the present invention, a stable toner image having no image quality fluctuation is obtained even if long-term continuous copying over 750,000 sheets is performed at 30 ° C. and 90% RH under an extremely high temperature and high humidity. As a result, it has been confirmed that a stable image forming technique using toner particles that does not cause a change in chargeability even under severe environmental conditions or image forming conditions has been established.
[Brief description of the drawings]
FIG. 1 is a schematic view of a toner dispersion passing device provided with a screen in which wires are mounted in a disk shape.
FIG. 2 is a schematic diagram of a toner dispersion liquid passing device in which a wire is fitted in a cylindrical shape and the toner dispersion liquid passes from the outside to the inside of the cylinder.
FIG. 3 is a schematic diagram of a toner dispersion liquid passing device in which a wire is fitted in a cylindrical shape and the toner dispersion liquid passes from the inside to the outside of the cylinder.
FIG. 4 is a schematic diagram showing an example of a screen in which wires are arranged at intervals.
FIG. 5 is a schematic diagram showing an example of a cross-sectional shape of a wire.
FIG. 6 is a schematic view showing a state in which slurry is passed through a screen.
FIG. 7 is a schematic diagram for explaining the influence of the shape of the screen surface on the passage of slurry when the slurry passes through the slit.
FIG. 8 is a schematic view showing an example of the structure of toner particles produced in the present invention.
[Explanation of symbols]
1 Toner dispersion liquid passage device
2 screens
3 Toner dispersion inlet
4 Toner dispersion outlet
21 Solid member (wire)
22 Slit (gap)
23 Screen surface
201 Cross section of wire (solid member)
202 Line segment adjacent to the straight line portion in the cross section of the wire (solid member)
203 Straight portion in cross section of wire (solid member)
204 Edge part in cross section of wire (solid member)
T toner particles
p Slit width
r Curvature radius
s Above screen surface
t Screen center
u Below screen

Claims (18)

An apparatus for producing an electrostatic charge image developing toner that forms particles in an aqueous medium and passes through a slurry state,
The manufacturing apparatus have a screen composed formed from wire having a slit for passing said slurry,
The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
An apparatus for producing an electrostatic charge image developing toner, wherein a curvature radius of the curved surface is 1 μm or more and 20 μm or less . An apparatus for producing an electrostatic charge image developing toner which forms particles in an aqueous medium and passes through a slurry state,
The manufacturing apparatus has a screen formed of a wire having a slit through which the slurry passes,
The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
Radius of curvature of the curved surface, characterized and to that electrostatic image developing toner production apparatus is not more than 5 times 0.25 times or more the average particle diameter Dv50 of the toner particles. Wherein the screen The toner production apparatus according to claim 1 or 2, characterized in that to form the screen surface as the same side straight portion in the cross-sectional shape of the wire. Slit of the screen is an electrostatic image developing toner production apparatus according to any one of claims 1 to 3, characterized in that formed in parallel to said wire at predetermined intervals. The cross-sectional shape of the wire is substantially electrostatic image developing toner production apparatus according to any one of claims 1-4, characterized in that those having a triangular shape. The width of the slit of the screen, an electrostatic charge image developing toner production apparatus according to any one of claims 1-5, characterized in that at 15μm or 50μm or less. It said wire The toner production apparatus according to any one of claims 1 to 6, characterized in that the nickel alloy. The apparatus for producing an electrostatic charge image developing toner according to claim 1 , wherein the apparatus having the screen has a drain . Any rate of the slurry as it passes through the screen, according to claim 1-8, characterized in that it comprises a control means for controlling the transport speed of 12.5 cm / min or more 167cm / min slurry as a less 2. An apparatus for producing a toner for developing an electrostatic charge image according to claim 1. The apparatus includes an ultrasonic application device that applies ultrasonic waves having a frequency of 10 kHz to 38 kHz and a power density of 0.01 W · cm ^{−2 to} 0.5 W · cm ^{−2 to the} screen. The manufacturing apparatus of the toner for electrostatic image development of any one of 1-9. A method for producing a toner for developing an electrostatic charge image by forming particles in an aqueous medium and passing through a slurry state,
The production method includes a step of passing particles contained in the slurry through a slit of a screen formed of a wire,
The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
The curved surface of curvature radius, manufacturing method of the electrostatic image developing toner characterized in that at 1μm or more 20μm or less. Through the slurry subjected to particle formation in an aqueous medium a manufacturing method of the electrostatic image developing preparative toner,
The production method includes a step of passing particles contained in the slurry through a slit of a screen formed of a wire,
The cross-sectional shape of the wire has at least one straight portion, and has a curved surface at an edge portion formed by the straight portion and a line segment adjacent to the straight portion,
The curved surface of curvature radius, manufacturing method of the electrostatic image developing toner you being a 0.25 to 5 times the average particle diameter Dv50 of the toner particles. 13. The electrostatic charge according to claim 11 , wherein the step of passing particles contained in the slurry through the slits of the screen allows the particles to pass from the screen surface side constituted by straight portions in the cross-sectional shape of the wire. A method for producing a toner for image development. Velocity through the slurry in the step of the pass, 12.5 cm / min or more 167cm / min and equal to or less than claims 11-13 any one of the toner for electrostatic image development according to Section Production method. On the screen, frequency 10kHz or 38kHz or less, in any one of claims 11 to 14, characterized in that the application of a power density 0.01 W · ^{cm -2} or more 0.5 W · ^{cm -2} or less ultrasound A method for producing a toner for developing an electrostatic charge image according to claim 1. The method for producing a toner for developing an electrostatic charge image according to any one of claims 11 to 15 , wherein an average particle size of particles in the slurry is 3 µm or more and 9 µm or less. The method for producing a toner for developing an electrostatic charge image according to any one of claims 11 to 16, wherein the particles in the slurry have a sea-island structure . An electrostatic charge image developing toner obtained by forming particles in an aqueous medium,
It is manufactured using the manufacturing apparatus according to any one of claims 1 to 10,
The toner number of free release agent particles present in the particle surface, the toner over a be that developing electrostatic images equal to or less than 3 per 100 toner particles.

Images