JP4026212B2 - Toner for developing electrostatic image and method for producing the same - Google Patents

Description

【０１１３】
ついで、３時間後から１時間おきに、反応樹脂溶液の約１０部をサンプリングし、同量のメチルエチルケトンで希釈し、ガードナー粘度計で粘度を測定した。粘度がＰ−Ｑとなる時点で、メチルエチルケトン/イソプロピルアルコールの５６７/６３部を添加し、温度が８０℃になってから、以下に示されるような割合の混合物を１時間にわたって滴下した。なお、この時のモノマー残存率をガスクロマトグラフィーで定量することで１段目の重合率を計算すると、６０％であった。
【０１１４】

【０１１５】
滴下終了後、３時間毎に３回「パーブチルＯ」の２部を添加し、さらに４時間反応を継続してから終了した。最後に、メチルエチルケトンで不揮発分が５０％になるように調整して樹脂溶液（Ａ−１）を得た。
【０１１６】
Ａ−１の樹脂特性
樹脂酸価：７０ ＫＯＨ（ｍｇ）／ｇ
モノマー混合物の酸価：組成１は７０、組成２は７０
設計Ｔｇ：組成１は２５℃、組成２は５０℃
モノマー重量比：組成１／組成２＝５０／５０
ＧＰＣ面積比：ＨＭｗ／ＬＭｗ＝２８／７２
組成別重量平均分子量：ＨＭｗは３６００００、ＬＭｗは３５０００
重量平均分子量：１２４０００
Ｔｇ：６１℃
【０１１７】
（参考例２） ３級アミノ基を有するスチレン−アクリル系共重合体の合成例
滴下装置、温度計、窒素ガス導入官、撹拌装置及び還流冷却器を備えた３リットルのフラスコに、メチルエチルケトンの６７０部を仕込んでから、８０℃に昇温し、下記の単量体類及び重合開始剤からなる混合物を、２時間かけて滴下した。
【０１１８】
スチレン ７３２部
アクリル酸ブチル １００部
メタクリル酸ジメチルアミノエチル １６８部
「パーブチルＯ」 ８部
【０１１９】
ついで、滴下を終了してから、３時間後から３時間おきに４回、各々重合触媒のパーブチルＯの２部を添加した。次に、パーブチルＯを添加してからさらに、４時間反応を継続してから終了した。最後に、不揮発分が５０％になるようにメチルエチルケトンで調整して樹脂溶液（Ａ−２）を得た。該樹脂のＴｇは６８℃、重量平均分子量１４２０００、及びアミン価３９であった。
【０１２０】
樹脂物性の説明
酸価：樹脂固形分１ｇを中和するのに要するＫＯＨのｍｇ数。
アミン価：樹脂固形分１ｇを中和するのに要するＨＣｌのｍｇ数。
設計Ｔｇ：重合性モノマーが１００％重合したと仮定したときのＴｇで、ＦＯＸの式に基づいた計算値である。
分子量：ポリスチレン換算ゲル・パーミュエーション・クロマトグラフ（ＧＰＣ）により測定した。
ＨＭｗ／ＬＭｗの面積比及び組成別重量平均分子量：測定したチャートの、谷（Bottom）を境にして分離したときの面積比。及び各面積部分の重量平均分子量。
重量平均分子量：全体を平均したときの重量平均分子量。
Ｔｇ：Differential Scanning Calorimetry （ＤＳＣ）により測定。
【０１２１】
着色剤と結着樹脂を必須成分とする樹脂粒子の作製
（参考例３）転相乳化法による、着色剤と結着樹脂を必須成分とする樹脂粒子の作製
Ａ−１の樹脂溶液の９００部と、「エルフテックス（ＥＬＦＴＥＸ）８」（米国キャボット社製のカーボンブラック）の５０部とを、「アイガーモーターミルＭ−２５０」（アイガージャパン社製のモーターミル）を使用して１時間の間混練せしめた。このミルベースの樹脂固形分/顔料の割合は、９０/１０になる。
【０１２２】
次に、得られたカーボン分散樹脂溶液に、ワックス微粒子液媒体分散体「Ｈ８０８」（中京油脂社製のエマルジョン型ワックス、フィッシャートロプシュワックス、粒子径０.５μｍ、固形分含有量３０％）の４５部を添加し、さらに、「アイガー・モーターミル Ｍ−２５０」によって、１０分間のあいだ混合、分散させた。ついで、不揮発分濃度を５１％に調整し、ミルベースを作製した。
【０１２３】
次いで、この混合物の３００部に対して、１規定の水酸化ナトリウム水溶液（中和剤）の２０.７部およびイソプロピルアルコールの３４部及びメチルエチルケトンの３０部及び、脱イオン水の９０部を加え、良く混合した後、内温を３０℃に保持し、攪拌しながら、これに、５ｍｌ/ｍｉｎで８分間にわたって脱イオン水を滴下し、転相乳化させた。さらに、３０分後に脱イオン水の３００部を加えた。尚、転相乳化時の温度は、３０℃で、両液温度の差がなくなる様に調製した。
【０１２４】
次に、減圧蒸留によって有機溶剤を除去し、処理液より着色剤内包樹脂粒子を濾別させたのち、当粒子を水中に再分散させた。続いてこの分散液を、０．１Ｎ塩酸水溶液（前記したのと逆極性の中和剤水溶液）にてｐＨ２．５に調整し、３０分間攪拌し、樹脂粒子中の樹脂を、元のカルボキシル基含有樹脂に変換した。
【０１２５】
得られた樹脂粒子を濾別した後、さらに水中に再分散し、固形分含有量を２０％となるよう脱イオン水により調整し、着色剤の内包された、樹脂粒子の水分散体溶液（Ｒ−１）を調整した。なお、樹脂粒子の水分散体溶液のＰＨは４．９であった。
【０１２６】
此処に得られた樹脂粒子の平均粒子径は、コールター・マルティサイザー２を用いた測定により、７．８ミクロン（μｍ）であった。また、ワーデルの実用球形度は０．９８であった。なお、得られたトナー粒子を樹脂に埋包し薄片化したサンプルを、ルテニウム酸四酸化物で染色後、ＴＥＭ（透過型電子顕微鏡）で観察したところ、着色剤、及びワックス微粒子がトナー粒子内に内包されておりカプセル型となっているのが確認された。
【０１２７】
（参考例４）重合法による、着色剤と結着樹脂を必須成分とする樹脂粒子の作製
スチレン ２４０ ｇ
アクリル酸ブチル ６０ ｇ
エチレングリコールジメタアクリレート ３ ｇ
アゾビスイソブチロニトリル ６ ｇ
ドデシルメルカプタン ３ ｇ
カーボンブラック １５ ｇ
［米国キャボット社製塩基性カーボンブラック］
ビスコール５５０Ｐ ３ ｇ
［三洋化成工業（株）製ポリプロピレンワックス］
【０１２８】
上記の混合物をＴ．Ｋ．ロボミクス（特殊機化工業（株）社製ホモミクサー）で分散させた後、ポリアクリル酸ソーダの１８部を溶解したイオン交換水１５００ｇを加え、分散懸濁させた。この混合液をファウドラー翼の付いた３Ｌのフラスコに入れ、窒素気流下、８０℃で１０時間懸濁重合を行い、着色剤が内包された樹脂粒子の水分散液を調製した。得られた樹脂粒子の平均粒径は、コールターマルティサイザー２により測定した結果８．０μｍであった。また、ワーデルの実用球形度は０．９７であった。
【０１２９】
この樹脂粒子水性分散液を濾過し、再度水に分散するという洗浄作業を数回繰り返し、最後に、固形分含有量を２０％となるよう脱イオン水により調整し、着色剤の内包された、樹脂粒子の水分散体溶液（Ｒ−２）を調整した。なお、樹脂粒子の水分散体溶液のＰＨは５．３であった。
【０１３０】
帯電制御剤含有樹脂水溶液の調製
（参考例５）
１Ｌの広口ポリ瓶に、Ａ−２の樹脂の１００部及びテトラヒドロフランの２００部及び１ＮＨＣｌ水溶液の５０部を添加し、均一に混合する。次に、ニグロシン化合物として、「ボントロンＮ−０７」（オリエント化学工業（株）社製正帯電性帯電制御剤）の２１．５部と、直径１ｍｍのガラスビーズの４００ｇを加え、ペイントコンデショナーにより３０分間分散を行った。分散終了後、４００倍の光学顕微鏡により観察したところ、樹脂溶液中に、ニグロシン化合物が均一に溶解していることが確認された。
【０１３１】
ニグロシン化合物が均一に溶解した、該樹脂溶液を、２Ｌのセパラブルフラスコに移し、撹拌下、脱イオン水を５０ｍｌ／ｍｉｎで１０分間滴下し、転相乳化を行った。滴下終了後、ここで得られた水性媒体分散液から、減圧蒸留によって、有機溶剤を除去し、帯電制御剤の水性分散液（Ｂ）を得た。該分散液を、４００倍の光学顕微鏡で観察したところ、均一に溶解していることが確認された。おそらく、帯電制御剤は、水溶性樹脂に吸着した形で、非常にミクロな状態で、分散しているものと推測される。
得られた水溶液の固形分含有量は、１０．４％であり、樹脂と帯電制御剤の重量比は７０／３０であった。
【０１３２】
（実施例１）
１０Ｌのステンレスパットに、Ｒ−１の樹脂粒子の水分散体溶液の３０００部（ＰＨ４．９）を仕込み、撹拌下に、帯電制御剤の水性分散液（Ｂ）の５７．８部をゆっくり滴下した。滴下終了後の樹脂粒子分散水溶液の水温２０℃、ＰＨは３．９であった。また、このときの樹脂粒子固形分に対し、（Ｂ）の添加量は１重量％であり、樹脂成分は０．７重量％、帯電制御剤成分は０．３重量％であった。
【０１３３】
次に、０．１Ｎアンモニア水を、４０ｍｌ／ｍｉｎで、ＰＨが９となるまで滴下し、帯電制御剤の水性分散液を、樹脂粒子表面に析出させた。滴下終了後、３０分間保持し、次いで、濾過を行った。このとき、濾液はクリアであり、流出物は認められなかった。また、３０分保持後の分散状態を、４００倍の光学顕微鏡で観察したところ、凝集、その他の異常は見られなかった。
【０１３４】
次に、濾過したウェットケーキを、固形分含有量が２０％となるように、脱イオン水に再分散し、３０分間撹拌、洗浄を行った。この後、濾過を再度行い、水媒体から、表面処理された樹脂粒子（トナー粒子）のウェットケーキを分離した。このときも、濾液はクリアであり、流出物は認められなかった。
この後、該ウェットケーキを凍結乾燥することで、帯電制御剤含有樹脂で表面処理された、トナー粒子を得た。
【０１３５】
得られたトナー粒子の体積平均粒子径は７．８μであり、表面処理前の樹脂粒子の粒径と変化は見られなかった。また、ＳＥＭ（走査型電子顕微鏡）により、粒子表面を観察したところ、３０〜１００ｎｍの微粒子が、均一に、粒子表面に固着しているのが観察された。また、ワーデルの実用球形度は、０．９８であった。
【０１３６】
該トナー粒子に対し、ヘンシェルミキサーで、シリカＨＤＫ Ｈ３０５０（ワッカー社製）を、０．３重量％外添した。次いで、アクリル・フッ素コートマグネタイトキャリアに対し、トナー濃度が３．３重量％となるように現像剤を調整した。
【０１３７】
この現像剤を、ボールミルにより、１００ｒｐｍで混合した後、ブローオフ帯電量及びイースパートアナライザー（ホソカワミクロン社製）により、測定を行った。
その結果、ブローオフ帯電量３８μＣ／ｇ、
逆帯電トナー粒子の個数％：２％、
１Femto Ｃ/１０μｍ以下の低帯電トナーの比率：５％
ｑ／ｄ：５Femto Ｃ/１０μｍ
であり、個々のトナー粒子が、十分な正帯電性を示し、かつ均一に帯電していることがわかる。
【０１３８】
（実施例２）
１０Ｌのステンレスパットに、Ｒ−１の樹脂粒子の水分散体溶液の３０００部（ＰＨ４．９）を仕込み、撹拌下に、帯電制御剤の水性分散液（Ｂ）の９６．３部をゆっくり滴下した。滴下終了後の樹脂粒子分散水溶液の水温２０℃、ＰＨは３．７であった。また、このときの樹脂粒子固形分に対し、（Ｂ）の添加量は１．６７重量％であり、樹脂成分は１．１７重量％、帯電制御剤成分は０．５重量％であった。
【０１３９】
次に、実施例１と同様の操作にて、帯電制御剤の水性分散液を、樹脂粒子表面に析出させた。このとき、実施例１と同様の挙動を示した。
【０１４０】
次に、濾過したウェットケーキを、固形分含有量が２０％となるように、脱イオン水に再分散し、３０分間撹拌、洗浄を行った。この後、濾過を再度行い、水媒体から、表面処理された樹脂粒子（トナー粒子）のウェットケーキを分離した。このときも、濾液はクリアであり、流出物は認められなかった。
この後、該ウェットケーキを凍結乾燥することで、帯電制御剤含有樹脂で表面処理された、トナー粒子を得た。
【０１４１】
得られたトナー粒子の体積平均粒子径は７．９μであり、表面処理前の樹脂粒子の粒径と変化は見られなかった。また、ＳＥＭ（走査型電子顕微鏡）により、粒子表面を観察したところ、３０〜１００ｎｍの微粒子が、実施例１よりもさらに密に、かつ、均一に、粒子表面に固着しているのが観察された。また、ワーデルの実用球形度は、０．９８であった。
【０１４２】
該トナー粒子に対し、ヘンシェルミキサーで、シリカＨＤＫ Ｈ３０５０（ワッカー社製）を、０．３重量％外添した。次いで、アクリル・フッ素コートマグネタイトキャリアに対し、トナー濃度が３．３重量％となるように現像剤を調整した。
【０１４３】
この現像剤を、ボールミルにより、１００ｒｐｍで混合した後、ブローオフ帯電量及びイースパートアナライザー（ホソカワミクロン社製）により、測定を行った。
その結果、ブローオフ帯電量４３μＣ／ｇ、
逆帯電トナー粒子の個数％：０．８％、
１Femto Ｃ/１０μｍ以下の低帯電トナーの比率：３％
ｑ／ｄ：５．４Femto Ｃ/１０μｍ
であり、個々のトナー粒子が、十分な正帯電性を示し、かつ均一に帯電していることがわかる。
【０１４４】
（実施例３）
１０Ｌのステンレスパットに、Ｒ−２の樹脂粒子の水分散体溶液の３０００部（ＰＨ５．３）を仕込み、撹拌下に、帯電制御剤の水性分散液（Ｂ）の５７．８部をゆっくり滴下した。滴下終了後の樹脂粒子分散水溶液の水温２０℃、ＰＨは４．３であった。また、このときの樹脂粒子固形分に対し、（Ｂ）の添加量は１重量％であり、樹脂成分は０．７重量％、帯電制御剤成分は０．３重量％であった。
【０１４５】
次に、実施例１と同様の操作にて、帯電制御剤の水性分散液を、樹脂粒子表面に析出させた。このとき、実施例１と同様の挙動を示した。
【０１４６】
次に、濾過したウェットケーキを、固形分含有量が２０％となるように、脱イオン水に再分散し、３０分間撹拌、洗浄を行った。この後、濾過を再度行い、水媒体から、表面処理された樹脂粒子（トナー粒子）のウェットケーキを分離した。このときも、濾液はクリアであり、流出物は認められなかった。
この後、該ウェットケーキを凍結乾燥することで、帯電制御剤含有樹脂で表面処理された、トナー粒子を得た。
【０１４７】
得られたトナー粒子の体積平均粒子径は８μｍであり、表面処理前の樹脂粒子の粒径と変化は見られなかった。また、ＳＥＭ（走査型電子顕微鏡）により、粒子表面を観察したところ、３０〜１００ｎｍの微粒子が、均一に、粒子表面に固着しているのが観察された。また、ワーデルの実用球形度は、０．９７であった。
【０１４８】
該トナー粒子に対し、ヘンシェルミキサーで、シリカＨＤＫ Ｈ３０５０（ワッカー社製）を、０．３重量％外添した。次いで、アクリル・フッ素コートマグネタイトキャリアに対し、トナー濃度が３．３重量％となるように現像剤を調整した。
【０１４９】
この現像剤を、ボールミルにより、１００ｒｐｍで混合した後、ブローオフ帯電量及びイースパートアナライザー（ホソカワミクロン社製）により、測定を行った。
その結果、ブローオフ帯電量４１μＣ／ｇ、
逆帯電トナー粒子の個数％：３％、
１Femto Ｃ/１０μｍ以下の低帯電トナーの比率：６．５％
ｑ／ｄ：６．７Femto Ｃ/１０μｍ
であり、個々のトナー粒子が、十分な正帯電性を示し、かつ均一に帯電していることがわかる。
【０１５０】
【発明の効果】
着色剤が内包された樹脂粒子の水性分散液と、別途調整した正帯電性帯電制御剤を含有した、塩基性基含有樹脂の微粒子分散体／又は水溶性樹脂溶液を混合し、前記樹脂粒子の表面に、正帯電性帯電制御剤を内包する塩基性基含有樹脂微粒子を析出させ、これを乾燥して、粒子表面に正帯電性帯電制御剤が、均一に固着したトナーを得ることにより、少量の帯電制御剤で、十分な正帯電量を有する、トナー粒子個々の帯電量が均一な、正帯電性トナーを得ることができる。また本製造方法では、着色剤が内包された樹脂粒子の極性にかかわらず、正帯電性トナーを製造することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic toner, and more particularly to a positively chargeable toner for electrophotography for use in developing an electrostatic image in dry electrophotography, and a method for producing the same.
[0002]
[Prior art]
As a method for producing a toner for developing an electrostatic charge image, in a dry method, a coloring agent is added to a binder resin, a charge control agent for imparting triboelectric chargeability to the toner, a wax for imparting hot offset resistance, and the like are added. A pulverization method is known in which melt-kneading, pulverization, and classification are performed. In this case, it is important that the charge control agent in each toner particle is uniformly finely dispersed so that each toner particle has uniform charging characteristics and can form a good copy image. .
[0003]
However, the charge control agent has a large particle size of 5 to 20 μm, and is not compatible with the binder resin. Therefore, in the pulverization method, a great deal of labor is required to disperse the charge control agent in the resin, and even if kneaded for a long time, it is difficult to disperse uniformly in the resin. As a result, there is a problem in that the copied image is soiled or the image is fogged.
[0004]
Furthermore, in the pulverization method, most of the charge control agent is encapsulated inside the particles, and only a small part of the charge control agent present on the surface layer of the particles contributes to the charge application, and is added. The charge control agent is wasted. This is not preferable from the viewpoint of resource saving and environmental problems.
[0005]
In addition, as a method for producing an electrostatic charge image developing toner, in a wet method, a polymerizable monomer containing a colorant is emulsified in an aqueous medium so as to have a desired toner particle size, and then polymerized. In this way, a so-called polymerization method for directly producing toner particles is known.
[0006]
In this polymerization method, a production method is known in which a polymerizable monomer containing a colorant and a charge control agent is similarly emulsified and then polymerized. However, as in the pulverization method, most of the charge control agent is contained inside the particles. Many of the added charge control agents are wasted, and the charge control agents are exposed non-uniformly on the particle surface, making it difficult to provide stable charge characteristics. .
[0007]
In addition, a method is known in which the charge control agent particles are adhered to the surface of the toner particles by mechanical dry external addition. In such a method, the charge control agent can be uniformly adhered to the surface of the polymer particles. It is difficult, or the compatibility between the resin and the charge control agent is low, so that there arises a problem that the charge control agent particles attached to the surface of the polymer particles easily fall off from the surface.
[0008]
JP-A-4-146447 proposes forming a charge control agent on the surface of a particle by imparting a carboxyl group to the surface of the polymer particle and adsorbing a cationic surfactant on the surface. Yes. However, in such a method, it is difficult to attach a sufficient amount of a cationic surfactant to the particle surface to cancel the negative chargeability due to the carboxyl group. That is, it is difficult to control the amount of adhesion when adhering by a physicochemical phenomenon called adsorption. As a result, the content of the reversely charged toner increases, causing problems such as background staining and fogging.
[0009]
As a method for producing a toner for developing an electrostatic charge image, a so-called phase inversion emulsification method described in JP-A-5-66600 is known as a wet method, in addition to a polymerization method. However, these are negatively chargeable toners, and cannot be used as positively chargeable toners even if external additives or carriers are changed.
[0010]
In the production method according to the above publication, a charge control agent-containing toner can be prepared by adding a charge control agent before phase inversion emulsification and then phase inversion emulsification. The problem that the control agent is encapsulated in the particles and the effect of the charge control agent is not sufficiently exhibited, and that the formation of particles during phase inversion emulsification deteriorates when an ionic substance such as a charge control agent is included. Also occurs.
[0011]
As a method for producing a positively chargeable toner by a phase inversion emulsification method, Japanese Patent Application Laid-Open No. 5-265247 discloses that a tertiary amino group is used as a binder resin component, and hydrophilicity is increased by neutralizing the resin. A method for producing toner particles by phase inversion emulsification in an aqueous medium has been proposed.
[0012]
However, in this production method, the positive chargeability of the toner is ensured, but the generation of an odor due to the amino group contained in a large amount is unavoidable, which is a great restriction when using the toner. Also in this production method, a charge control agent-containing toner can be prepared by adding a charge control agent before phase inversion and then emulsifying the phase inversion, but as described above, The control agent is encapsulated in the particles, and the effect of the charge control agent is not sufficiently exhibited. In addition, if an ionic substance such as a charge control agent is included, particle formation at the time of phase inversion emulsification deteriorates. Arise.
[0013]
[Problems to be solved by the invention]
[0014]
That is, the object of the present invention is to have a small amount of positively chargeable charge control agent uniformly fixed on the surface of resin particles containing colorants and a final resin as essential components, and positively chargeable with excellent charging characteristics. A toner and a method for producing a positively chargeable toner excellent in charging characteristics, in which a small amount of a positively chargeable charge control agent is uniformly fixed on the surface of resin particles obtained by a pulverization method, a polymerization method or a phase inversion emulsification method. It is to provide.
[0015]
In particular, the present invention provides a positively chargeable toner excellent in charging characteristics, in which a small amount of a positively chargeable charge control agent is uniformly fixed on the surface of negatively chargeable resin particles obtained by a phase inversion emulsification method, and a method for producing the same. Objective.
[0016]
[Means for Solving the Problems]
[0017]
Therefore, as a result of intensive investigations aimed at the problems to be solved by the invention as described above, the present inventors have found that the positively chargeable charge control agent is uniformly dissolved or less than 1 μm as the toner particle structure. A basic group-containing resin containing a dispersed basic group-containing resin as an essential component and containing the positive charge control agent is fixed on the surface of resin particles containing a colorant and a binder resin as essential components. It has been found that a chargeable electrostatic image developing toner solves the above-mentioned problems.
[0018]
As an example of a method for obtaining a positively chargeable electrostatic image developing toner having such a particle structure, neutralization is performed on a dispersion of resin particles (I) containing a colorant and a binder resin as essential components by neutralization. Fine particles obtained by phase inversion emulsification of a mixture containing a basic group-containing resin and water-dispersible / or water-soluble basic group and a positively chargeable charge control agent, having a particle size smaller than that of the resin particles (I) The above-mentioned problem can be solved by adding a water-soluble resin solution (II) or a water-soluble resin solution (II) separately and fixing a resin containing a basic group containing a positively chargeable charge control agent to the resin particle surface. As a result, the present invention has been completed.
[0019]
That is, the present invention provides the following inventions.
Resin particles (I) having a colorant and a binder resin as essential components and a basic group-containing resin in which a positively chargeable charge control agent is uniformly dissolved or dispersed to 1 μm or less are included as essential components, and the positive charge control A positively chargeable electrostatic image developing toner (hereinafter referred to as a first invention) in which a basic group-containing resin containing an agent is fixed to the surface of a resin particle (I).
[0020]
An essential component is an aqueous dispersion of resin particles (I) having a colorant and a binder resin as essential components, a basic group-containing resin that becomes self-water-dispersible / or water-soluble by neutralization, and a positively chargeable charge control agent. The resin particles (I) obtained by phase inversion emulsification in a water-based medium in the presence of a neutralizing agent, wherein the positively chargeable charge control agent is dissolved or dispersed to 1 μm or less, encapsulated, or adsorbed. The aqueous dispersion of fine particles / or the water-soluble resin solution (II) having an average particle size smaller than that of (3) is uniformly mixed and deposited on the toner particle surface with a neutralizing agent having a polarity opposite to that of the neutralizing agent. Next, the liquid medium is then removed and dried, and a method for producing a positively chargeable toner in which a basic group-containing resin containing a positively chargeable control agent is fixed to the toner particle surface (hereinafter referred to as the second invention). .
[0021]
The second invention is preferably performed by the following method.
That is, a colorant obtained by phase-emulsifying a mixture containing an acidic group-containing resin and a colorant, which are self-dispersible by neutralization, as essential components in an aqueous medium in the presence of a neutralizer, A method for producing a positively chargeable toner (hereinafter, referred to as a third invention), characterized by using encapsulated spherical resin particles (I).
[0022]
The toner of the first invention has, for example, the following characteristics in its particle structure.
1. The positively chargeable charge control agent is dissolved or finely dispersed in the basic group-containing resin in a state of 1 μm or less.
2. In the above state, the basic group-containing resin containing the positively chargeable charge control agent is substantially 30 to 300 nm in particle form, and is uniformly fixed to the resin particle surface.
3. The basic group of the basic group-containing resin is preferably a tertiary amino group.
4). The resin particles preferably contain an acidic group, and the acidic group is a carboxyl group.
5). The shape of the resin particles is not limited, but preferably, the Wadel practical sphericity of the resin particles is 0.95 or more.
[0023]
By having the above structural features, the following effects are exhibited.
1. The positively chargeable charge control agent is dissolved or finely dispersed in the basic group-containing resin in a state of 1 μm or less, and the basic group-containing resin containing the positively chargeable charge control agent in the above state is substantially 30 to The particles are 300 nm in size and are uniformly fixed on the surface of the resin particles. As a result, a sufficient amount of positive charge and uniform chargeability of individual toner particles can be achieved with a small amount of positive charge control agent regardless of the polarity of the resin particles.
2. In the case of spherical particles having a Wadel's practical sphericity of 0.95 or more for the resin particles, the surface treatment is uniformly performed, so that uniform chargeability of individual toner particles is further achieved.
3. When the resin particles have an acidic group, preferably a carboxyl group, the fine particles of the basic group-containing resin containing the positively chargeable charge control agent are more firmly fixed to the particle surface by the acid-base interaction. In addition, deterioration of development characteristics due to peeling is reduced.
[0024]
In order to obtain the toner of the first invention, various production methods can be considered. For example, the production method of the second invention can be given as an example.
[0025]
In the second invention, the aqueous dispersion of the resin particles (I) to which the particles containing the positively chargeable charge control agent are fixed can be obtained by any manufacturing method. For example, the aqueous dispersion can be obtained by a pulverization method. A dispersion of resin particles dispersed in an aqueous medium in the presence of a dispersion stabilizer, or an aqueous dispersion of particles obtained by a wet method such as a polymerization method, or a dispersion stabilizer It is included that a dispersion of resin particles obtained by the method of phase inversion emulsification can be used. In this case, since a dispersion stabilizer is used in each case, the basic group-containing resin fine particles (II) containing a positively chargeable charge control agent can be fixed after the particles are sufficiently washed. This is preferable from the viewpoint of environmental stability of the toner.
[0026]
The third invention is characterized in that an aqueous dispersion of resin particles obtained by a phase inversion emulsification method is used. The characteristic of the resin particles obtained by the phase inversion emulsification method is that the practical sphericity of Wardel is 0.95 or more, and the particles can be formed without using a dispersion stabilizer. The characteristic that there is little influence on a characteristic is mention | raise | lifted.
[0027]
That is, in this case, the resin particles (I) having a colorant and a binder resin as essential components are neutralized with an acidic group-containing resin that becomes self-dispersible by neutralization and a mixture containing the colorant as essential components. Spherical particles encapsulating a colorant obtained by phase inversion emulsification in an aqueous medium in the presence of the agent.
[0028]
The second aspect of the invention is an aqueous dispersion of resin particles (I) containing a colorant and a binder resin as essential components, and a basic group which is separately adjusted and becomes self-water-dispersible / or water-soluble by neutralization. The positively chargeable charge control agent obtained by phase inversion emulsification of the mixture containing the contained resin and the positively chargeable charge control agent in an aqueous medium in the presence of a neutralizing agent is dissolved or dispersed to 1 μm or less. The neutralizing agent is uniformly mixed with an aqueous dispersion of fine particles having a mean particle size smaller than that of the resin particles (I) and / or the water-soluble resin solution (II) encapsulated or adsorbed. And a positively chargeable toner having the characteristics of the invention 1 can be easily produced.
[0029]
Before describing the steps of the present invention, each component used in the present invention will be described.
The binder resin that can be used in the present invention may be any resin that can be used as a toner binder resin. Among them, in particular, an acidic group-containing resin that becomes self-water-dispersible by neutralization and a basic group-containing resin that becomes self-water-dispersible / or water-soluble by neutralization are used by using phase inversion emulsification. Will be described next.
[0030]
In the present invention, the resin that can be made self-dispersible by neutralization means that an emulsifier and a dispersion stabilizer are added under the action of an aqueous medium by the action of a functional group in the molecule that can increase hydrophilicity by neutralization. A resin having the ability to form a stable aqueous dispersion or aqueous solution without substantial use. If the resin has an acidic group in a resin that can be self-dispersible by neutralization (acid that can increase hydrophilicity by neutralization or resin that has a basic functional group in the molecular chain) If the base has a basic group, it can be neutralized with an acid to make the functional group into a salt structure to enhance hydrophilicity.
[0031]
The degree of hydrophilicity can be appropriately adjusted by the degree of neutralization (neutralization rate). In this case, the degree of hydrophilicity must be such that the resin itself can be dispersed in water. Such a self-water dispersible resin is mixed with an aqueous medium to cause phase inversion emulsification and generate particles.
[0032]
The hydrophilicity of a resin containing an acid group or a basic group that can be made self-dispersible by neutralization can be controlled by the amount of functional groups or the amount of neutralization (neutralization rate) that can increase hydrophilicity by neutralization. . Moreover, it can also be set as a self-water-dispersible resin by reducing the neutralization rate using resin which can become water-soluble when neutralized more than a certain neutralization rate.
[0033]
In the production method of the present invention, the basic group-containing resin is preferably a resin that can become water-soluble when neutralized to a certain neutralization rate or higher.
[0034]
Furthermore, the hydrophilicity determines the size of the particles during dispersion in phase inversion emulsification. That is, it is possible to easily obtain an arbitrary particle size by controlling the neutralization rate.
[0035]
Examples of the functional group that can be increased in hydrophilicity by neutralization of the resin in the resin include, for example, a carboxyl group, a phosphoric acid group, a sulfone group, a sulfuric acid group, and the like as an acidic group, and among them, a carboxyl group is preferable. Examples of basic groups include primary, secondary and tertiary amino groups, and quaternary ammonium groups. Among them, tertiary amino groups are preferable.
[0036]
The amount (neutralization amount, neutralization rate) of functional groups such as neutralized acidic groups or basic groups necessary for the resin to exhibit self-water dispersibility or water solubility is the composition, molecular weight, and structure. Since the hydrophilicity of the resin itself varies depending on the resin, etc., the neutralization rate varies depending on the resin, but in the case of an acidic group, the acid value is preferably in the range of 30 to 150 (mgKOH / g).
[0037]
In the case of a basic group, the amine value is preferably within a range of 20 to 100 (mg HCl / g).
[0038]
In addition, the salt structure taken by the neutralized functional group can be obtained by neutralizing the functional group in the resin that can be self-dispersible by neutralization with a neutralizing agent immediately before phase inversion emulsification. The effect is the same even if the resin already exists in the resin as a salt structure.
[0039]
In practicing the present invention, it is necessary to convert part or all of the acidic or basic functional group contained in a resin that becomes self-dispersible or water-soluble by neutralization into a salt structure. In some cases, a part or all of the functional groups contained in the resin can be appropriately adjusted by neutralizing with a neutralizing agent having the opposite polarity.
[0040]
As a resin that can become self-water-dispersible or water-soluble by neutralization, a radically polymerizable resin, particularly a styrene / acrylate copolymer-based resin, in which a balance of powder flowability and fixability as a toner can be obtained relatively easily. Is preferred. Next, the radical polymerizable resin will be described in detail as an example.
[0041]
Acidic group-containing resins that can become self-water dispersible by neutralization include radical polymerizable monomers containing acid groups as described above and radical polymerizable monomers containing acid groups. Those obtained by radical polymerization of these radical polymerizable monomers in the presence of a radical initiator can be used.
[0042]
As a resin obtained by such a production method, for example, the following method can also be employed.
1) A resin that can be self-water-dispersible by neutralization is obtained. Apart from that, a resin that has compatibility with the above-mentioned, but can be self-water-dispersible with a different weight average molecular weight Mw from the above. Get two or more seeds and mix these two or more. That is, a method of synthesizing two or more kinds of resins having different weight average molecular weights separately and mixing them so as to have a predetermined ratio (simple blend resin).
[0043]
2) In the same reaction vessel (in-situ), one kind of radical polymerizable monomer mixture was polymerized in advance until the polymerization rate reached 20 to 80%, and then another kind of the same mixture was polymerized. A method of using a resin (in-situ resin), which is a polymer (resin), and in which two or more of different weight average molecular weights Mw in the above 1 are blended as a result.
[0044]
The basic group-containing resin that can be made self-dispersible / or water-soluble by neutralization includes polymerizable monomers containing a basic group and polymerizable monomers containing this basic group. Those obtained by radical polymerization of other polymerizable monomers in the presence of a radical initiator can be used.
[0045]
The polymerization reaction for obtaining these can be used as appropriate in solution polymerization, suspension and emulsion polymerization.
[0046]
Examples of such acidic group-containing polymerizable monomers include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconic acid, monobutyl maleate and the like. Examples of basic group-containing polymerizable monomers include acrylate derivatives and methacrylate derivatives such as dimethylaminoethyl, diethylaminoethyl, dibutylaminoethyl, and N-ethyl-N-phenylaminoethyl. Moreover, N-vinyl compounds, such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, are also mentioned.
[0047]
Examples of polymerizable monomers other than acidic group or basic group-containing polymerizable monomers include, for example, styrene monomers (aromatic vinyl monomers), styrene, vinyl toluene, 2-methylstyrene, t- There is butyl styrene or chlorostyrene.
[0048]
Examples of acrylic esters include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, and acrylic acid. Examples include 2-ethylhexyl, n-octyl acrylate, decyl acrylate or dodecyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, and methyl alpha chloroacrylate.
[0049]
Furthermore, as the methacrylic acid ester, for example, methyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-methacrylic acid n- Examples include octyl, decyl methacrylate, dodecyl methacrylate, 2-chloroethyl methacrylate, phenyl methacrylate, and alpha chloromethyl methacrylate.
[0050]
In addition, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, Etc.
[0051]
Moreover, when obtaining the said resin, a general purpose organic solvent can be used in the case of solution polymerization. Examples of the organic solvent to be used include various hydrocarbons such as toluene, xylene, benzene, n-hexane, cyclohexane and n-heptane; methanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol, sec- Alcohols such as butanol and t-butanol; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoisopropyl ether, propylene glycol mono n-butyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, Ether alcohols such as ethylene glycol mono n-butyl ether; acetone, methyl ethyl ketone, Various ketones such as til isobutyl ketone; Various esters such as ethyl acetate, butyl acetate and isobutyl acetate; Various ether esters such as propylene glycol monoethyl ether acetate and ethylene glycol monoethyl ether acetate; Various cyclic ethers such as tetrahydrofuran Various organic solvents such as various halogenated hydrocarbons such as methylene chloride can be used.
[0052]
As the polymerization initiator to be used, various known and commonly used organic peroxide initiators and azo initiators can be used. Specific examples include peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, sodium persulfate, and ammonium persulfate, and azo series such as azobisisobutyronitrile and azobisisovaleronitrile. Compounds.
[0053]
As acidic group containing resin, the inside of the range which is 30-150 (mgKOH / g) as an acid value is preferable, for example. Moreover, it is preferable to use the thing of a weight average molecular weight 6000-300000. Furthermore, it is preferable to use a glass transition temperature of 45 to 70 ° C.
[0054]
As the basic group-containing resin, for example, an amine value in the range of 20 to 100 (mg HCl / g) is preferable. Moreover, it is preferable to use those having a weight average molecular weight of 2,000 to 400,000, preferably 6,000 to 300,000. Furthermore, it is preferable to use a glass transition temperature of 30 to 120 ° C.
[0055]
The neutralizing agent used in the present invention will be described. The neutralizing agent used in the present invention must be properly used as follows. In order to convert an acidic group-containing resin into self-water dispersibility, a basic neutralizing agent is used, and in order to convert a basic group-containing resin into self-water dispersible / or water-soluble, an acidic group is used. The neutralizing agent is used. Moreover, in order to return the acidic group-containing resin that has become a salt structure by neutralization to the original acidic group, an acidic neutralizer is used. Further, a basic neutralizing agent is used in order to return the basic group-containing resin, which has become a salt structure by neutralization, to the original basic group and precipitate it on the surface of the resin particles.
[0056]
Examples of basic neutralizing agents include inorganic metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide, inorganic alkalis such as ammonia, alkanolamines such as monoethanolamine and diethanolamine, dimethylamine and diethylamine Secondary amines, tertiary amines such as triethylamine, organic amines such as hydrazine, and acidic ones such as inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, formic acid, acetic acid, oxalic acid, p-toluene Examples include organic acids such as sulfonic acid, and these are used in an appropriate amount.
[0057]
Neutralization of the resin that can become self-water dispersible by neutralization may be performed immediately before mixing with the aqueous medium at the time of phase inversion emulsification, or may be performed simultaneously with mixing with the aqueous medium during the phase inversion process. .
[0058]
A general-purpose colorant can be used as the colorant in the present invention. Specifically, for example, carbon black, magnetic powder, aniline blue, calcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengara, C. I. Pigment red 122, C.I. I. Pigment yellow 97, C.I. I. Pigment Blue 15, iron trioxide, iron sesquioxide, iron powder, zinc oxide, selenium and the like can be mentioned, and one or a combination of two or more can be used.
[0059]
The amount of the colorant used in the present invention is usually selected from the range of 3 to 15 parts by weight per 100 parts by weight of the resin solid content.
[0060]
In the present invention, examples of the positively chargeable charge control agent include Bontron N-01, Bontron N-07, and Bontron EX (manufactured by Orient Chemical Industry Co., Ltd.) as the nigrosine compound. As the quaternary ammonium salt compound, Bontron P-51,52 (manufactured by Orient Chemical Co., Ltd.), copy charge PSY VP2038 (manufactured by Hoechst), TP-415,302 (manufactured by Hodogaya Chemical Co., Ltd.) ). An example of the triphenylmethane derivative is copy blue PR (Hoechst). In addition, a basic dye can be used.
[0061]
In the present invention, when the positively chargeable charge control agent is dissolved or cannot be dissolved in the basic group-containing resin at a molecular level, it is 1 μm or less, more preferably 500 nm or less by known and conventional means. It is necessary to disperse as follows.
[0062]
The amount of the charge control agent added to the surface of the resin particles is 0.01 to 5% by weight, preferably 0.01 to 2% by weight, based on the solid content of the resin particles. However, the appropriate amount of the positively chargeable charge control agent varies depending on the characteristics of the resin, the characteristics of the external additive, and the characteristics of the carrier, and therefore is appropriately determined depending on the case.
[0063]
In the present invention, the organic solvent can be used as necessary, and any organic solvent may be used as long as it dissolves the resin. Moreover, you may use the organic solvent used by resin synthesis as it is. As described above, for example, aromatic hydrocarbon solvents such as toluene, xylene and benzene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ether solvents such as tetrahydrofuran, halogen solvents such as carbon tetrachloride, trichloromethane and dichloromethane A solvent is used. In this case, for example, by using a water-soluble or partially water-soluble organic solvent such as acetone, butanol, isopropyl alcohol, and the like, the generation of particles in phase inversion emulsification is facilitated.
[0064]
Preference is given to using so-called low-boiling solvents such as acetone, methyl ethyl ketone or ethyl acetate, tetrahydrofuran, which can be easily desolvated.
[0065]
Examples of other components (additive components) that can be used in the present invention include various auxiliaries such as a mold release agent, which are appropriately selected and used depending on the purpose of use and conditions of use. I can do it.
[0066]
Examples of the auxiliary agent include waxes such as polyethylene wax, polypropylene wax, and paraffin wax, metal soaps, lubricants such as zinc stearate, among others, an aqueous dispersion of synthetic wax synthesized by the Fischer-Tropsch method, Or an emulsion type thing can be added in the resin solution before phase inversion emulsification, and can be included in particle | grains after phase inversion emulsification.
[0067]
Next, the steps of the production method of the present invention will be described. The present invention can be roughly divided into four steps. That is, a step (1) of obtaining an aqueous dispersion of resin particles (I) containing a colorant and a binder resin as essential components, a fine particle dispersion of a basic group-containing resin containing a positively chargeable charge control agent, and Step (2) for separately preparing water-soluble resin solution (II) and (I) and (II) are uniformly mixed, and a positively chargeable charge control agent is formed on the surface of the resin particles (I). A step (3) for precipitating fine particles / or an aqueous solution of the basic group-containing resin containing, and then a step (4) for removing the liquid medium and drying to obtain a toner powder. Of course, either step (1) or step (2) may be performed first or at the same time. The explanation will be given for each process.
[0068]
Step (1) is a step of obtaining an aqueous dispersion of resin particles containing a binder resin and a colorant as essential components.
[0069]
These particles may be obtained by any method as described above. In some cases, a dispersion stabilizer or the like can be used to disperse the particles in an aqueous medium. In particular, the use of a method in which particles are obtained as an aqueous dispersion by a wet method such as a polymerization method or a phase inversion emulsification method is preferred in that the step of dispersing the particles in an aqueous medium can be omitted.
[0070]
Phase-inversion emulsification in an aqueous medium in the presence of a neutralizing agent, a mixture containing an acidic group-containing resin that becomes self-dispersible by neutralization and a colorant as an essential component without using a dispersion stabilizer or emulsifier When the other steps in the present invention are the same, the method of the present invention using the aqueous dispersion containing spherical particles encapsulating the colorant obtained as described above is, for example, an external dispersion stabilizer or an external emulsifier. Or a method using an aqueous dispersion containing spherical particles containing a colorant obtained by a polymerization method or a phase inversion emulsification method, or a neutralization containing a nonionic atomic group. A method of using an aqueous dispersion containing spherical particles encapsulating a colorant, obtained by phase inversion emulsification of a mixture containing at least a resin having self-water dispersibility and a colorant as essential components. Compared to the following, for example, the cleaning process is simpler Not only it has the advantage over processes that can, charging property of the finally obtained toner is also preferable because a better.
[0071]
In order to obtain a resin particle dispersion by the phase inversion emulsification method without using a dispersion stabilizer or an emulsifier, a neutralizing agent is added to and mixed with an acidic group-containing resin that can be made self-dispersible by neutralization. After the acid group-containing resin having a salt structure is obtained, the mixture containing this and the colorant as essential components and an organic solvent that dissolves the resin as necessary is prepared. It can carry out by the method of phase inversion emulsification.
[0072]
However, furthermore, an acidic group-containing resin that can become self-dispersible by neutralization, and a colorant as essential components, a mixture containing an organic solvent is prepared as necessary, and then any arbitrary until just before phase inversion emulsification Simultaneously with the step or phase inversion emulsification, it can also be carried out by a method of neutralizing an acidic group-containing resin that can be made self-dispersible by neutralization. In this way, a dispersion of resin particles (I) made of an acidic group-containing resin partially containing a salt structure and containing a colorant is obtained.
[0073]
In the preparation of the above mixture, for example, an acid group-containing resin in which a part of the acid groups has a salt structure by a neutralizer, a colorant, and, if necessary, an organic solvent are used as well-known conventional means. The mixture is prepared by mixing and dispersing. For mixing and dispersing, known and commonly used means such as a ball mill, a sand mill, and a motor mill can be employed.
[0074]
In addition, as the organic solvent used when preparing the mixture, any of those described above can be used. When the resin is subjected to solution polymerization, the same organic solvent used at that time can be used. As described above, the organic solvent used in the solution polymerization and the organic solvent used for preparing the mixture may be used in different ways.
[0075]
In preparing the mixture, a water-soluble or partially water-soluble organic solvent such as acetone, butanol, isopropyl alcohol, or the like is included therein, thereby facilitating the generation of resin particles in this step.
[0076]
The non-volatile content in the mixture is usually adjusted within a range of 20 to 80% by weight.
[0077]
In addition, an acidic group-containing resin that can become self-water dispersible by neutralization and a coloring agent as essential components, and after preparing a mixture containing an organic solvent as necessary, contains an acidic group that can become self-water dispersible by neutralization In the method of neutralizing the resin, the aqueous medium used for phase inversion emulsification uses an aqueous medium containing an amount of a neutralizing agent necessary to make the acidic group-containing resin self-dispersible, and phase inversion emulsification is performed. At the same time, neutralization is performed, or neutralization is performed at an arbitrary stage until immediately before phase inversion. Preferably, it is desirable to add the neutralizing agent immediately before the addition of the aqueous medium.
[0078]
In any case, a dispersion of the resin particles (I) containing the colorant is obtained by phase inversion emulsification of the mixture in the corresponding aqueous medium. In that case, phase inversion emulsification may be performed by adding the corresponding aqueous medium to the mixture, or phase inversion emulsification by adding the mixture to the corresponding aqueous medium.
[0079]
In step (1), an aqueous dispersion containing resin particles (I) having an average particle diameter of usually 3 to 12 μm is obtained.
[0080]
The resin particles (I) described above may be those obtained by removing the organic solvent from the aqueous dispersion after phase inversion emulsification. In the production method of the present invention, the resin particles (I) are re-dispersed in the aqueous medium after removing the organic solvent from the aqueous dispersion after phase inversion emulsification, separating the aqueous medium and washing the wet cake. The salt portion contained in the acidic group-containing resin is preferably returned to the original acidic group with an aqueous hydrochloric acid solution.
[0081]
As a result, acidic groups are exposed on the surface of the resin particles, and the fine particles of the basic group-containing resin containing the positively chargeable charge control agent deposited on the particle surface in the third step are strongly strengthened by the acid-base interaction. Stick.
[0082]
In step (2), a mixture containing a basic group-containing resin that becomes self-water-dispersible / water-soluble by neutralization and a positively chargeable charge control agent in an aqueous medium in the presence of a neutralizing agent An aqueous dispersion of fine particles obtained by phase inversion emulsification, having a mean particle size smaller than that of the resin particles (I), in which the positively chargeable charge control agent is dissolved, dispersed, or dispersed within 1 μm or less, or adsorbed. This is a step of obtaining a water-soluble resin solution (II).
[0083]
One of the important points in the present invention is that the positively chargeable charge control agent is dissolved or finely dispersed to 1 μm or less. Usually, since the charge control agent is an ionic substance, it is difficult to dissolve in an organic solvent, and even if dissolved, the solubility is often small.
[0084]
In the present invention, the basic group-containing resin having a salt structure with the neutralizing agent and the organic solvent for dissolving the resin are selected from, for example, the above-mentioned alcohol solvents, ketone solvents, or ether solvents. Any organic solvent may be used as long as it is used, but among these, a mixed solvent of methyl ethyl ketone and tetrahydrofuran is preferably used for the purpose of the present invention. Combined with the high polarity of the resin, it can be dissolved or dispersed to 1 μm or less in most of the positively chargeable charge control agent. At this time, a mechanical shearing force may be applied by a bead mill or the like to promote dispersion.
[0085]
The ratio between the positively chargeable charge control agent and the basic group-containing resin is 5/95 to 80/20, preferably 10/90 to 50/50, by weight.
[0086]
The aqueous dispersion (II) can be obtained by the same operation as the resin particles (I) in the step (1). When the aqueous dispersion of (II) becomes fine particles, the average particle size needs to be smaller than that of the resin particles (I), and is preferably 0.01 to 2 μm.
In particular, the optimum aqueous dispersion state is desirably water-soluble. At this time, it is presumed that the positively chargeable charge control agent is adsorbed on the molecular chain of the basic group-containing resin.
[0087]
In the production method of the present invention, since the phase inversion proceeds smoothly due to the combination of the positively chargeable charge control agent and the basic group-containing resin, an aqueous dispersion (II) in a good state can be obtained. Care must be taken when the charge control agent and the functional group of the resin have opposite polarities because the charge control agent adsorbs to cause phase inversion failure and phase inversion deteriorates.
[0088]
Moreover, since the resin particle (I) obtained by the phase inversion emulsification method in the most preferred embodiment of the present invention has an acidic group, it exhibits negative chargeability. In this case, when the positively charged toner is obtained by the production method of the present invention, the combination of the positively chargeable charge control agent and the acidic group-containing resin results in insufficient desired positive chargeability. A combination of a basic charge control agent and a basic group-containing resin is preferred.
[0089]
The aqueous dispersion (II) preferably removes the organic solvent from the aqueous dispersion after phase inversion emulsification.
[0090]
In step (3), (I) and (II) obtained in steps (1) and (2) above are uniformly mixed to convert a part or all of the basic group into a salt structure, It is a process of adding a basic neutralizing agent to a basic group-containing resin with enhanced hydrophilicity to return it to the original non-neutralized (unneutralized) basic group. By the treatment, the hydrophilicity of the resin containing the positively chargeable charge control agent is lowered, and the resin is uniformly deposited on the surface of the resin particle (I) including the colorant. At this time, they are firmly fixed to the surface of the resin particle (I).
[0091]
In this case, if the deposition rate of the resin is too high, the fine particles are aggregated and not uniformly deposited on the particle surface, but also the resin particles are aggregated, which is not preferable.
[0092]
In the production method of the present invention, a resin having a tertiary amino group as a basic group is used, and the resin is neutralized with a strong acid, and then treated with ammonia, which is a weak base, to thereby reduce the deposition rate of the resin. Slowing down makes it difficult for the fine particles to agglomerate with each other, and can uniformly adhere to the surface of the resin particles.
[0093]
The amount of the solid in the dispersion (II) obtained in the step (2) added to the aqueous dispersion of the resin particles (I) is 0.05 to 10% by weight with respect to the solid content of the resin particles (I). %, More preferably 0.1 to 6% by weight.
[0094]
The precipitation step is generally performed under stirring. As a stirring blade, a thing with little entrainment of air like a Faudler blade is preferable.
[0095]
The amount of the basic neutralizing agent used for precipitation is, for example, when the water temperature is 20 ° C. and the solid content of the mixture of the resin particles (I) and the dispersion liquid (II) is 20%, PH 9 to 10 Add until it becomes. After adjusting to a predetermined pH, the mixture is stirred for about 30 minutes to completely adhere to the resin particle surface.
[0096]
In the step (4), the toner particles obtained in the step (3) and having the resin containing the charge control agent fixed on the surface are separated from the liquid medium and dried to obtain a powder toner.
[0097]
The toner particles removed and separated from the liquid medium are dried to obtain a toner powder. For this drying, any known and commonly used method can be employed. For example, hot air drying may be performed at a temperature at which the toner particles are not thermally fused or aggregated, or freeze drying may be used. There is also a method of simultaneously separating and drying the toner particles from the aqueous medium using a spray dryer or the like.
[0098]
As the particle size of the toner powder composed of toner particles used in the present invention, an arbitrary size can be selected within a practical level as a toner. From the viewpoint of matching with the current machine, those having a volume average particle diameter in the range of 3 to 12 μm are preferable.
[0099]
The toner obtained by the production method of the present invention can be used as a non-magnetic one-component toner or a magnetic one-component toner, or as a two-component developer by combining with a carrier, and has a high quality due to good charging characteristics. An image can be obtained.
[0100]
As the carrier, any known and conventional ones can be used. For example, metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earth and their alloys or oxides, surface-treated glass, silica Etc. can be used. Of course, resin-coated carriers such as acrylic resin-coated carriers, fluororesin-coated carriers, fluorine / acrylic resin-coated carriers, and silicone resin-coated carriers can also be used. As the carrier, for example, a carrier of about 20 to 200 microns is used.
[0101]
DETAILED DESCRIPTION OF THE INVENTION
1. Resin particles (I) having a colorant and a binder resin as essential components and a basic group-containing resin in which a positively chargeable charge control agent is uniformly dissolved or dispersed to 1 μm or less are included as essential components, and the positive charge control A positively chargeable toner for developing an electrostatic image, in which a basic group-containing resin containing an agent is fixed to the surface of the resin particle (I).
[0102]
2. 2. The toner according to 1 above, wherein the resin particles (I) are made of a binder resin containing an acidic group.
[0103]
3. The toner according to 1 or 2 above, wherein the basic group is a tertiary amino group.
[0104]
4). 4. The toner according to 2 or 3 above, wherein the acidic group is a carboxyl group.
[0105]
5). 5. The toner according to 1, 2, 3, or 4, wherein the toner particles have a Wadel practical sphericity of 0.95 or more.
[0106]
6). An essential component is an aqueous dispersion of resin particles (I) having a colorant and a binder resin as essential components, a basic group-containing resin that becomes self-water-dispersible / or water-soluble by neutralization, and a positively chargeable charge control agent. The resin particles (I) obtained by phase inversion emulsification in a water-based medium in the presence of a neutralizing agent, wherein the positively chargeable charge control agent is dissolved or dispersed to 1 μm or less, encapsulated, or adsorbed. The aqueous dispersion of fine particles and / or the water-soluble resin solution (II) having an average particle size smaller than that of) are uniformly mixed and deposited on the toner particle surface with a neutralizing agent having a polarity opposite to that of the neutralizing agent. And then removing and drying the liquid medium, and a method for producing a toner in which a basic group-containing resin containing a positive charge control agent is fixed to the toner particle surface.
[0107]
7). In the presence of a neutralizing agent, a resin particle (I) containing a coloring agent and a binder resin as essential components is a mixture containing an acidic group-containing resin and a coloring agent that are self-dispersible by neutralization as essential components. 7. The production method according to 6 above, which is spherical particles obtained by phase inversion emulsification in an aqueous medium and encapsulating a colorant.
[0108]
8). An aqueous dispersion of resin particles (I) containing a colorant and a binder resin as essential components is obtained by re-dispersing in an aqueous medium what has been returned to its original acidic group by acid treatment after phase inversion emulsification. 8. The production method according to 6 or 7 above.
[0109]
In the most preferred embodiment of the present invention, for example, various polar resins can be used as the binder resin in the resin particles (I), but most preferable is self-water dispersion by neutralization containing an acid group. In order to adhere the positive charge control agent to the particles (I) using a self-water dispersible resin obtained by neutralizing a resin that can be neutralized with a base, self-water dispersion can be achieved by neutralization containing a basic group. A self-water dispersible resin obtained by neutralizing a resin with an acid is used, and a positive charge control agent is localized on the particle (I) surface using a base.
[0110]
【Example】
Next, the present invention will be described more specifically with reference to comparative examples and examples. In the following, all parts and% are based on weight.
[0111]
Resin synthesis example
Reference Example 1 Synthesis Example of Styrene-Acrylic Copolymer Having Carboxyl Group Into a 3 liter flask equipped with a dropping device, a thermometer, a nitrogen gas introduction tube, a stirring device and a reflux condenser, methyl ethyl ketone / isopropyl alcohol / After charging 114/12/24 parts of water, the temperature was raised to 80 ° C., and a mixture consisting of the following monomers and polymerization initiator was charged all at once to initiate the reaction.
[0112]

[0113]
Next, about 10 parts of the reaction resin solution was sampled every 3 hours after 3 hours, diluted with the same amount of methyl ethyl ketone, and the viscosity was measured with a Gardner viscometer. When the viscosity reached PQ, 567/63 parts of methyl ethyl ketone / isopropyl alcohol was added, and after the temperature reached 80 ° C., a mixture having the ratio shown below was added dropwise over 1 hour. The monomer residual ratio at this time was quantified by gas chromatography, and the first stage polymerization rate was calculated to be 60%.
[0114]

[0115]
After completion of the dropwise addition, 2 parts of “perbutyl O” was added 3 times every 3 hours, and the reaction was further continued for 4 hours. Finally, the resin solution (A-1) was obtained by adjusting the non-volatile content to 50% with methyl ethyl ketone.
[0116]
Resin characteristics of A-1
Resin acid value: 70 KOH (mg) / g
Acid value of monomer mixture: 70 for composition 1 and 70 for composition 2
Design Tg: composition 1 is 25 ° C., composition 2 is 50 ° C.
Monomer weight ratio: composition 1 / composition 2 = 50/50
GPC area ratio: HMw / LMw = 28/72
Weight average molecular weight by composition: HMw is 360000, LMw is 35000
Weight average molecular weight: 124,000
Tg: 61 ° C
[0117]
(Reference Example 2) Synthesis example of styrene-acrylic copolymer having tertiary amino group
After charging 670 parts of methyl ethyl ketone into a 3 liter flask equipped with a dropping device, a thermometer, a nitrogen gas introducer, a stirrer, and a reflux condenser, the temperature was raised to 80 ° C., and the following monomers and polymerization were performed. The mixture consisting of the initiator was added dropwise over 2 hours.
[0118]
732 parts of styrene
100 parts of butyl acrylate
168 parts of dimethylaminoethyl methacrylate
"Perbutyl O" 8 parts
[0119]
Then, 2 parts of perbutyl O as a polymerization catalyst were added 4 times every 3 hours from 3 hours after the dropping was completed. Next, after adding perbutyl O, the reaction was further continued for 4 hours, and then terminated. Finally, the resin solution (A-2) was obtained by adjusting with methyl ethyl ketone so that the nonvolatile content was 50%. The resin had a Tg of 68 ° C., a weight average molecular weight of 142,000, and an amine value of 39.
[0120]
Description of resin properties
Acid value: The number of mg of KOH required to neutralize 1 g of resin solids.
Amine value: The number of mg of HCl required to neutralize 1 g of resin solids.
Design Tg: Tg when the polymerizable monomer is assumed to be 100% polymerized, which is a calculated value based on the FOX equation.
Molecular weight: Measured by gel permeation chromatograph (GPC) in terms of polystyrene.
HMw / LMw area ratio and weight-average molecular weight by composition: area ratio of the measured chart when separated from the bottom (Bottom). And the weight average molecular weight of each area portion.
Weight average molecular weight: Weight average molecular weight when the whole is averaged.
Tg: Measured by differential scanning calorimetry (DSC).
[0121]
Production of resin particles containing colorant and binder resin as essential components
(Reference Example 3) Preparation of resin particles containing colorant and binder resin as essential components by phase inversion emulsification method
900 parts of the resin solution of A-1 and 50 parts of “ELFTEX 8” (carbon black manufactured by Cabot Corporation in the United States) were combined with “Eiger Motor Mill M-250” (motor mill manufactured by Eiger Japan). ) And kneaded for 1 hour. The millbase resin solids / pigment ratio is 90/10.
[0122]
Next, 45% of wax fine particle liquid medium dispersion “H808” (Emulsion type wax, Fischer-Tropsch wax, particle diameter 0.5 μm, solid content 30%) manufactured by Chukyo Yushi Co., Ltd. was added to the obtained carbon dispersion resin solution. Then, the mixture was further mixed and dispersed for 10 minutes by “Eiger Motormill M-250”. Subsequently, the non-volatile content concentration was adjusted to 51% to produce a mill base.
[0123]
Next, 20.7 parts of a 1N aqueous sodium hydroxide solution (neutralizing agent), 34 parts of isopropyl alcohol, 30 parts of methyl ethyl ketone, and 90 parts of deionized water are added to 300 parts of this mixture. After mixing well, the internal temperature was kept at 30 ° C., and while stirring, deionized water was added dropwise at 5 ml / min for 8 minutes to effect phase inversion emulsification. Further, after 30 minutes, 300 parts of deionized water was added. The temperature at the time of phase inversion emulsification was 30 ° C., and the temperature was adjusted so that there was no difference between the two liquid temperatures.
[0124]
Next, the organic solvent was removed by distillation under reduced pressure, and after the colorant-containing resin particles were filtered off from the treatment liquid, the particles were redispersed in water. Subsequently, this dispersion was adjusted to pH 2.5 with a 0.1N hydrochloric acid aqueous solution (neutralizing agent aqueous solution having the opposite polarity as described above), and stirred for 30 minutes, so that the resin in the resin particles was replaced with the original carboxyl group Converted to containing resin.
[0125]
After the obtained resin particles are filtered off, they are further redispersed in water, adjusted with deionized water so that the solid content is 20%, and an aqueous dispersion solution of resin particles (including a colorant) ( R-1) was adjusted. The pH of the aqueous dispersion solution of resin particles was 4.9.
[0126]
The average particle size of the resin particles obtained here was 7.8 microns (μm) as measured with Coulter Multisizer 2. The practical sphericity of Wardel was 0.98. A sample obtained by embedding the obtained toner particles in a resin and slicing them was stained with ruthenate tetraoxide and then observed with a TEM (transmission electron microscope). As a result, the colorant and wax fine particles were found in the toner particles. It was confirmed that it was encapsulated in a capsule shape.
[0127]
(Reference Example 4) Production of resin particles containing colorant and binder resin as essential components by polymerization method
240 g of styrene
60 g of butyl acrylate
Ethylene glycol dimethacrylate 3 g
Azobisisobutyronitrile 6 g
Dodecyl mercaptan 3 g
Carbon black 15 g
[Basic carbon black manufactured by Cabot, USA]
Viscol 550P 3 g
[Sanyo Kasei Kogyo Polypropylene Wax]
[0128]
The above mixture is treated with T.W. K. After dispersing with ROBOMIX (Homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.), 1500 g of ion-exchanged water in which 18 parts of sodium polyacrylate was dissolved was added and dispersed and suspended. This mixed solution was put into a 3 L flask equipped with a Faudler blade, and suspension polymerization was performed at 80 ° C. for 10 hours under a nitrogen stream to prepare an aqueous dispersion of resin particles containing a colorant. The average particle diameter of the obtained resin particles was 8.0 μm as a result of measurement by Coulter Multisizer 2. Moreover, the practical sphericity of Wardel was 0.97.
[0129]
This resin particle aqueous dispersion was filtered, and the washing operation of dispersing in water again was repeated several times. Finally, the solid content was adjusted to 20% with deionized water, and the colorant was encapsulated. An aqueous dispersion solution (R-2) of resin particles was prepared. The pH of the aqueous dispersion solution of resin particles was 5.3.
[0130]
Preparation of resin solution containing charge control agent
(Reference Example 5)
To a 1 L wide-mouthed plastic bottle, 100 parts of A-2 resin, 200 parts of tetrahydrofuran and 50 parts of 1N HCl aqueous solution are added and mixed uniformly. Next, 21.5 parts of “Bontron N-07” (a positively chargeable charge control agent manufactured by Orient Chemical Co., Ltd.) and 400 g of glass beads having a diameter of 1 mm were added as a nigrosine compound, and 30 by a paint conditioner. Dispersion was performed for a minute. After the completion of the dispersion, when observed with a 400 × optical microscope, it was confirmed that the nigrosine compound was uniformly dissolved in the resin solution.
[0131]
The resin solution in which the nigrosine compound was uniformly dissolved was transferred to a 2 L separable flask, and deionized water was added dropwise at 50 ml / min for 10 minutes with stirring to perform phase inversion emulsification. After completion of dropping, the organic solvent was removed from the aqueous medium dispersion obtained here by distillation under reduced pressure to obtain an aqueous dispersion (B) of a charge control agent. When the dispersion was observed with a 400 × optical microscope, it was confirmed that the dispersion was uniformly dissolved. Probably, the charge control agent is presumed to be dispersed in a very microscopic state adsorbed on the water-soluble resin.
The solid content of the obtained aqueous solution was 10.4%, and the weight ratio of the resin to the charge control agent was 70/30.
[0132]
Example 1
Into a 10 L stainless steel pad is charged 3000 parts (PH4.9) of an aqueous dispersion solution of R-1 resin particles, and 57.8 parts of an aqueous dispersion (B) of a charge control agent is slowly added dropwise with stirring. did. The water temperature of the resin particle-dispersed aqueous solution after completion of dropping was 20 ° C., and the pH was 3.9. The amount of (B) added was 1% by weight, the resin component was 0.7% by weight, and the charge control agent component was 0.3% by weight based on the solid content of the resin particles.
[0133]
Next, 0.1N ammonia water was added dropwise at 40 ml / min until PH reached 9, and an aqueous dispersion of the charge control agent was deposited on the surface of the resin particles. After completion of dropping, the mixture was kept for 30 minutes and then filtered. At this time, the filtrate was clear and no effluent was observed. Moreover, when the dispersion state after 30-minute holding | maintenance was observed with the optical microscope of 400 time, aggregation and other abnormality were not seen.
[0134]
Next, the filtered wet cake was redispersed in deionized water so that the solid content was 20%, and stirred and washed for 30 minutes. Thereafter, filtration was performed again to separate the wet cake of the surface-treated resin particles (toner particles) from the aqueous medium. At this time, the filtrate was clear and no effluent was observed.
Thereafter, the wet cake was freeze-dried to obtain toner particles surface-treated with a charge control agent-containing resin.
[0135]
The obtained toner particles had a volume average particle diameter of 7.8 μm, and no change was observed in the particle diameter of the resin particles before surface treatment. Moreover, when the particle surface was observed by SEM (scanning electron microscope), it was observed that fine particles of 30 to 100 nm were uniformly fixed to the particle surface. Moreover, the practical sphericity of Wardel was 0.98.
[0136]
The toner particles were externally added with 0.3% by weight of silica HDK H3050 (manufactured by Wacker) using a Henschel mixer. Next, the developer was adjusted so that the toner concentration was 3.3% by weight with respect to the acrylic / fluorine-coated magnetite carrier.
[0137]
This developer was mixed with a ball mill at 100 rpm, and then measured with a blow-off charge amount and an espert analyzer (manufactured by Hosokawa Micron).
As a result, the blow-off charge amount is 38 μC / g,
Number% of reversely charged toner particles: 2%
1Femto C / 10μm or less of low-charged toner ratio: 5%
q / d: 5 Femto C / 10 μm
It can be seen that the individual toner particles are sufficiently positively charged and are uniformly charged.
[0138]
(Example 2)
Into a 10 L stainless steel pad, 3000 parts (PH 4.9) of an aqueous dispersion solution of R-1 resin particles was charged, and 96.3 parts of an aqueous dispersion (B) of a charge control agent was slowly added dropwise with stirring. did. The water temperature of the resin particle-dispersed aqueous solution after completion of the dropwise addition was 20 ° C., and the pH was 3.7. The amount of (B) added was 1.67% by weight, the resin component was 1.17% by weight, and the charge control agent component was 0.5% by weight with respect to the solid content of the resin particles.
[0139]
Next, an aqueous dispersion of the charge control agent was deposited on the surface of the resin particles by the same operation as in Example 1. At this time, the same behavior as in Example 1 was exhibited.
[0140]
Next, the filtered wet cake was redispersed in deionized water so that the solid content was 20%, and stirred and washed for 30 minutes. Thereafter, filtration was performed again to separate the wet cake of the surface-treated resin particles (toner particles) from the aqueous medium. At this time, the filtrate was clear and no effluent was observed.
Thereafter, the wet cake was freeze-dried to obtain toner particles surface-treated with a charge control agent-containing resin.
[0141]
The obtained toner particles had a volume average particle diameter of 7.9 μm, and no change was observed in the particle diameter of the resin particles before surface treatment. Further, when the particle surface was observed by SEM (scanning electron microscope), it was observed that the fine particles of 30 to 100 nm were adhered to the particle surface more densely and uniformly than Example 1. It was. Moreover, the practical sphericity of Wardel was 0.98.
[0142]
The toner particles were externally added with 0.3% by weight of silica HDK H3050 (manufactured by Wacker) using a Henschel mixer. Next, the developer was adjusted so that the toner concentration was 3.3% by weight with respect to the acrylic / fluorine-coated magnetite carrier.
[0143]
This developer was mixed with a ball mill at 100 rpm, and then measured with a blow-off charge amount and an espert analyzer (manufactured by Hosokawa Micron).
As a result, the blow-off charge amount is 43 μC / g,
Number% of reversely charged toner particles: 0.8%
Ratio of low-charged toner of 1 Femto C / 10 μm or less: 3%
q / d: 5.4 Femto C / 10 μm
It can be seen that the individual toner particles are sufficiently positively charged and are uniformly charged.
[0144]
(Example 3)
Into a 10 L stainless steel pad is charged 3000 parts (PH5.3) of an aqueous dispersion solution of R-2 resin particles, and 57.8 parts of an aqueous dispersion (B) of a charge control agent is slowly added dropwise with stirring. did. The water temperature of the resin particle-dispersed aqueous solution after completion of dropping was 20 ° C., and the pH was 4.3. The amount of (B) added was 1% by weight, the resin component was 0.7% by weight, and the charge control agent component was 0.3% by weight based on the solid content of the resin particles.
[0145]
Next, an aqueous dispersion of the charge control agent was deposited on the surface of the resin particles by the same operation as in Example 1. At this time, the same behavior as in Example 1 was exhibited.
[0146]
Next, the filtered wet cake was redispersed in deionized water so that the solid content was 20%, and stirred and washed for 30 minutes. Thereafter, filtration was performed again to separate the wet cake of the surface-treated resin particles (toner particles) from the aqueous medium. At this time, the filtrate was clear and no effluent was observed.
Thereafter, the wet cake was freeze-dried to obtain toner particles surface-treated with a charge control agent-containing resin.
[0147]
The obtained toner particles had a volume average particle diameter of 8 μm, and no changes were observed in the particle diameter of the resin particles before the surface treatment. Moreover, when the particle surface was observed by SEM (scanning electron microscope), it was observed that fine particles of 30 to 100 nm were uniformly fixed to the particle surface. In addition, the practical sphericity of Wardel was 0.97.
[0148]
The toner particles were externally added with 0.3% by weight of silica HDK H3050 (manufactured by Wacker) using a Henschel mixer. Next, the developer was adjusted so that the toner concentration was 3.3% by weight with respect to the acrylic / fluorine-coated magnetite carrier.
[0149]
This developer was mixed with a ball mill at 100 rpm, and then measured with a blow-off charge amount and an espert analyzer (manufactured by Hosokawa Micron).
As a result, the blow-off charge amount 41 μC / g,
Number% of reversely charged toner particles: 3%
Ratio of low-charged toner of 1 Femto C / 10 μm or less: 6.5%
q / d: 6.7 Femto C / 10 μm
It can be seen that the individual toner particles are sufficiently positively charged and are uniformly charged.
[0150]
【The invention's effect】
An aqueous dispersion of resin particles encapsulating a colorant and a fine particle dispersion of a basic group-containing resin / or a water-soluble resin solution containing a separately prepared positively chargeable charge control agent are mixed, and the resin particles By depositing basic group-containing resin fine particles encapsulating a positively chargeable charge control agent on the surface, and drying this, a small amount of toner is obtained by obtaining a toner in which the positively chargeable charge control agent is uniformly fixed on the particle surface. With this charge control agent, it is possible to obtain a positively chargeable toner having a sufficient positive charge amount and uniform charge amount of individual toner particles. Further, in this production method, a positively chargeable toner can be produced regardless of the polarity of the resin particles encapsulating the colorant.

Claims (7)

As essential components, a colorant, a resin particle (I) having a binder resin containing an acidic group as essential components, and a basic group-containing resin in which a positively chargeable charge control agent is uniformly dissolved or dispersed to 1 μm or less are included. A positively chargeable electrostatic image developing toner in which a basic group-containing resin containing the positive charge control agent is fixed to the surface of the resin particle (I). The toner according to claim 1, wherein the basic group is a tertiary amino group. The toner according to claim 1, wherein the acidic group is a carboxyl group. The toner according to claim 1, wherein the toner particles have a Wadel practical sphericity of 0.95 or more. An aqueous dispersion of resin particles (I) containing a binder and an acidic group-containing binder resin as essential components, and self-water dispersibility by neutralization and / Alternatively, a positively chargeable charge control agent obtained by phase inversion emulsification of a mixture containing a basic group-containing resin that becomes water-soluble and a positively chargeable charge control agent in an aqueous medium in the presence of a neutralizer. Is an aqueous dispersion of fine particles having an average particle size smaller than that of the resin particles (I), wherein the resin particles are dissolved, dispersed in 1 μm or less, encapsulated, or adsorbed / Alternatively, the water-soluble resin solution (II) is uniformly mixed and deposited on the toner particle surface with a neutralizing agent having a polarity opposite to that of the neutralizing agent, and then the liquid medium is removed from the toner particle surface and dried. And a method for producing a toner having a basic group-containing resin containing a positive charge control agent fixed thereto. In the presence of a neutralizing agent, a resin particle (I) containing a coloring agent and a binder resin as essential components is a mixture containing an acidic group-containing resin and a coloring agent that become self-water dispersible upon neutralization. The production method according to claim 5, which is a spherical particle obtained by phase inversion emulsification in an aqueous medium and encapsulating a colorant. An aqueous dispersion of resin particles (I) containing a colorant and a binder resin as essential components is obtained by re-dispersing in an aqueous medium what was returned to the original acidic group by acid treatment after phase inversion emulsification. The manufacturing method according to claim 6.