JP2005049394A - Method for manufacturing electrostatic charge image developing toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for obtaining toner particles having uniform dispersion of particles of a release agent in the toner particles without being exposed on the surfaces and having narrow and sharp distribution of the particle size in the manufacture of toner by an emulsion dispersion method. <P>SOLUTION: A release agent and a binder resin having a carboxyl group are preliminarily finely dispersed in an organic solvent, and the preliminarily finely dispersed liquid is stabilized by a high pressure homogenizer to prepare a stabilized fine dispersion liquid of the release agent, to which a binder resin having a carboxyl group and an organic pigment are added and dispersed to prepare a colored resin solution. Then a basic compound is added to the colored resin solution, which is emulsified in an aqueous medium to produce fine particles of the colored resin solution. Then a dispersion stabilizer and an electrolyte are successively added to produce agglomerates of the fine particles, or after the organic solvent in the fine particles of the colored resin solution is removed, an electrolyte is added to produce aggregates of the fine particles, which are then melted to produce an associated product. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００８９】
表１において、各略号は以下のものを示す。
ＴＭＡ；無水トリメリット酸
ＴＰＡ；テレフタル酸
ＩＰＡ；イソフタル酸
ＢＰＡ−ＰＯ；ポリオキシプロピレン（２．４）−２，２−ビス（４−ヒドロキシフェニル）プロパン
ＢＰＡ−ＥＯ；ポリオキシエチレン（２．４）−２，２−ビス（４−ヒドロキシフェニル）プロパン
ＥＧ；エチレングリコール
ＦＴ値；フローテスター値
【００９０】
ＦＴ値は、定荷重押出形細管式レオメータである島津製作所製フローテスタＣＦＴ−５００を用いて測定される。フローテスターでの測定条件は、ピストン断面積１ｃｍ^２ 、シリンダ圧力０．９８ＭＰａ、ダイ長さ１ｍｍ、ダイ穴径１ｍｍ、測定開始温度５０゜Ｃ、昇温速度６゜Ｃ／ｍｉｎ、試料重量１．５ｇの条件で行った。
また、表１のＴｆｂ、Ｔ１／２、Ｔｅｎｄは、フローテスターによる流れ試験での昇温温度ＴとピストンのストロークＳとの関係を示すグラフにおいて、樹脂の流出が始まって急激にストロークが大きくなり、カーブが立ち上がったときの温度をＴｆｂとし、樹脂の流出がほぼ終了してカーブがねたときの温度をＴｅｎｄとし、ＴｆｂのときのストロークとＴｅｎｄのときのストロークとの中間のストロークをとるときの温度をＴ１／２としている。
また、ガラス転移温度である「Ｔｇ」（℃）は 、島津製作所製示差走査熱量計（ＤＳＣ−５０）を用い、セカンドラン法により毎分１０℃の昇温速度で測定したオンセット値である。
【００９１】
（着色剤マスター溶液の調製例）
カーボンブラック顔料とポリエステル樹脂（表１のＲ１）とを４０／６０の重量比率で有機溶剤（メチルエチルケトン）中に添加し、デスパーにてプレ分散を行った後、モーターミルＭ−１０００（米国アイガー社製）で湿式分散を行い、カーボンブラック顔料のマスター溶液Ｐ１を調整した。マスター溶液の性状を表２に示す。また、カーボンブラック顔料には、キャボット社製カーボンブラック「Ｅｌｆｔｅｘ−８」を使用した。
【００９２】
【表２】

【００９３】
（離型剤予備分散体の調製例１）
カルナバワックス「カルナバワックス １号」（加藤洋行輸入品）３０部とポリエステル樹脂（表１の合成例Ｒ１）７０部とを加圧ニーダーで混練し、離型剤の微分散体Ｗ−１を得た。
【００９４】
（離型剤予備分散液の調製例２）
フィッシャートロプシュワックス「ＦＴ−１００」（日本精蝋株式会社製）５０部、ポリエステル樹脂（表１の合成例Ｒ１）５０部及びメチルエチルケトン１５０部をデスパーでプレ分散した後、パールミルＳＴＳ−１型（アシザワ・ファインテック株式会社製）で分散を行い、固形分含有量を３５重量％に調整し、離型剤の微分散液Ｗ−２を得た。
【００９５】
（実施例１）
（離型剤安定微分散溶液の調製工程）
上記離型剤分散体Ｗ−１を１６．７部、Ｒ１の樹脂を１５．０部、メチルエチルケトンを３８．７部量り採り、デスパーでプレ分散した後、高圧ホモジナイザー「ＨＶ−ＯＨ−０７−３．７ＳＳ型」（（株）イズミフードマシナリ製）を用いて、１パスの処理を行った。このときの処理圧力は６０ＭＰａであった。得られた分散液を４００倍の光学顕微鏡で観察したところ、離型剤の一次粒子はいずれも２μｍ以下であった。
（ミルベースの調製工程）
得られた離型剤安定微分散溶液を攪拌翼としてマックスブレンド翼を有する円筒型のセパラブルフラスコに移し、さらに着色剤マスター溶液Ｐ１の２５部、Ｒ１の樹脂を１９．８部、Ｒ２の樹脂を３６部、メチルエチルケトンを３０．６部加え、温度を３０〜３５℃に保持しながら３時間溶解分散を行い、ミルベースを得た。得られたミルベースを４００倍の光学顕微鏡で観察したところ、離型剤の微粒子は均一に分散しているのが観察された。
【００９６】
（転相乳化工程）
前記ミルベースの５４５．５部をマックスブレンド翼を有する円筒型のセパラブルフラスコに仕込み、次いで１規定アンモニア水４７．８部（カルボン酸に対する当量は１．２）を加えて、スリーワンモーターにより２１０ｒｐｍにて十分に攪拌した後、脱イオン水１３３部を加え、さらに攪拌を行い、温度を２３℃に調製した。ついで、同条件下で１３３部の脱イオン水を滴下して転相乳化により微粒子分散体を作製した。この時の攪拌翼の周速は０．７１ｍ／ｓであった。次に、脱イオン水２７９部を加えて（１規定アンモニア水と水の総量が５９３部となる量の脱イオン水量）溶剤量を調整した。
（合一工程）
次いで、アニオン型乳化剤であるエマール０（花王社製）の２．８部を水３０部に希釈して添加した。その後、温度を２５℃に、また回転数を１５８ｒｐｍに調整し、５．２％の硫酸アンモニュウムの水溶液を粒径が５．５μｍに成長するまで滴下し、その後、同条件で粒径が７μｍに成長するまで攪拌を続け合一操作を終了した。この時の硫酸アンモニュウムの添加量は３００部であった。また、攪拌翼の周速は０．５４ｍ／ｓであった。得られた粒子を４００倍の光学顕微鏡で観察したところ、いずれも均一な粒子であり、粒度分布も良好であった。
その後、減圧下に有機溶剤と水の一部を留去し、固液分離、洗浄後、乾燥してトナー粒子を得た。
【００９７】
（実施例２）
（離型剤安定微分散溶液の調製工程）
上記離型剤分散液Ｗ−２を２８．６部、Ｒ１の樹脂を１５．０部、メチルエチルケトンを１２．０部量り採り、デスパーでプレ分散した後、高圧ホモジナイザー「ＨＶ−ＯＨ−０７−３．７ＳＳ型」（（株）イズミフードマシナリ製）を用いて、１パスの処理を行った。このときの処理圧力は６０ＭＰａであった。得られた分散液を４００倍の光学顕微鏡で観察したところ、離型剤の一次粒子はいずれも１μｍ以下であった。
（ミルベースの調製工程）
得られた離型剤安定微分散溶液を攪拌翼としてマックスブレンド翼を有する円筒型のセパラブルフラスコに移し、さらに着色剤マスター溶液Ｐ１の２５部、Ｒ１の樹脂を２６．５部、Ｒ２の樹脂を３６部、メチルエチルケトンを３８．７部加え、温度を３０〜３５℃に保持しながら３時間溶解分散を行い、ミルベースを得た。得られたミルベースを４００倍の光学顕微鏡で観察したところ、離型剤の微粒子は均一に分散しているのが観察された。
【００９８】
（転相乳化工程）
前記ミルベースの５４５．５部をマックスブレンド翼を有する円筒型のセパラブルフラスコに仕込み、次いで１規定アンモニア水４７．８部（カルボン酸に対する当量は１．２）を加えて、スリーワンモーターにより２１０ｒｐｍにて十分に攪拌した後、脱イオン水１３３部を加え、さらに攪拌を行い、温度を２３℃に調製した。ついで、同条件下で１３３部の脱イオン水を滴下して転相乳化により微粒子分散体を作製した。この時の攪拌翼の周速は０．７１ｍ／ｓであった。次に、脱イオン水２７９部を加えて（１規定アンモニア水と水の総量が５９３部となる量の脱イオン水量）溶剤量を調整した。
（合一工程）
次いで、アニオン型乳化剤であるエマール０（花王社製）の２．８部を水３０部に希釈して添加した。その後、温度を２５℃に、また回転数を１５８ｒｐｍに調整し、５．２％の硫酸アンモニュウムの水溶液を粒径が５．５μｍに成長するまで滴下し、その後、同条件で粒径が７μｍに成長するまで攪拌を続け合一操作を終了した。この時の硫酸アンモニュウムの添加量は３１０部であった。また、攪拌翼の周速は０．５４ｍ／ｓであった。得られた粒子を４００倍の光学顕微鏡で観察したところ、いずれも均一な粒子であり、粒度分布も良好であった。
その後、減圧下に有機溶剤と水の一部を留去し、固液分離、洗浄後、乾燥してトナー粒子を得た。
【００９９】
（比較例１）
（離型剤分散溶液の調製工程）
上記離型剤分散液Ｗ−２を２８．６部、Ｒ１の樹脂を１５．０部、メチルエチルケトンを１２．０部量り採り、デスパーでプレ分散した。得られた分散液を４００倍の光学顕微鏡で観察したところ、離型剤の一次粒子はいずれも１μｍ以下であった。
（ミルベースの調製工程）
得られた離型剤分散溶液を、攪拌翼としてマックスブレンド翼を有する円筒型のセパラブルフラスコに移し、さらに着色剤マスター溶液Ｐ１の２５部、Ｒ１の樹脂を２６．５部、Ｒ２の樹脂を３６部、メチルエチルケトンを３８．７部加え、温度を３０〜３５℃に保持しながら３時間溶解分散を行い、ミルベースを得た。得られたミルベースを４００倍の光学顕微鏡で観察したところ、離型剤の微粒子は均一に分散しているのが観察された。
【０１００】
（転相乳化工程）
前記ミルベースを５４５．５部仕込み、次いで１規定アンモニア水４７．８部（カルボン酸に対する当量は１．２）を加えて、スリーワンモーターにより２１０ｒｐｍにて十分に攪拌した後、脱イオン水１３３部を加え、さらに攪拌を行い、温度を２３℃に調製した。ついで、同条件下で１３３部の脱イオン水を滴下して転相乳化により微粒子分散体を作製した。この時の攪拌翼の周速は０．７１ｍ／ｓであった。次に、脱イオン水２７９部を加えて（１規定アンモニア水と水の総量が５９３部となる量の脱イオン水量）溶剤量を調整した。
（合一工程）
次いで、アニオン型乳化剤であるエマール０（花王社製）の２．８部を水３０部に希釈して添加した。その後、温度を２５℃に、また回転数を１５８ｒｐｍに調整し、５．２％の硫酸アンモニュウムの水溶液を粒径が５．５μｍに成長するまで滴下し、その後、同条件で粒径が７μｍに成長するまで攪拌を続け合一操作を終了した。この時の硫酸アンモニュウムの添加量は２７０部であった。また、攪拌翼の周速は０．５４ｍ／ｓであった。得られた粒子を４００倍の光学顕微鏡で観察したところ、粗大粒子、微粒子が共存し粒度分布はブロードであった。また、粗大粒子の中には離型剤微粒子と推測される微粒子の凝集体が露出しているものも観察された。
その後、減圧下に有機溶剤と水の一部を留去し、固液分離、洗浄後、乾燥してトナー粒子を得た。
【０１０１】
（比較例２）
（離型剤分散溶液の調製工程）
上記離型剤分散体Ｗ−１を１６．７部、Ｒ１の樹脂を１５．０部、メチルエチルケトンを３８．７部量り採り、デスパーでプレ分散した後、アイガーモーターミル「Ｍ−１０００」（米国アイガー社製）を用いて、１パスの処理を行った。得られた分散液を４００倍の光学顕微鏡で観察したところ、離型剤の一次粒子はいずれも１μｍ以下であった。
（ミルベースの調製工程）
得られた離型剤分散溶液を攪拌翼としてマックスブレンド翼を有する円筒型のセパラブルフラスコに移し、さらに着色剤マスター溶液Ｐ１の２５部、Ｒ１の樹脂を１９．８部、Ｒ２の樹脂を３６部、メチルエチルケトンを３０．６部加え、温度を３０〜３５℃に保持しながら３時間溶解分散を行い、ミルベースを得た。得られたミルベースを４００倍の光学顕微鏡で観察したところ、離型剤の微粒子は均一に分散しているのが観察された。
【０１０２】
（転相乳化工程）
前記ミルベースの５４５．５部をマックスブレンド翼を有する円筒型のセパラブルフラスコに仕込み、次いで１規定アンモニア水４７．８部（カルボン酸に対する当量は１．２）を加えて、スリーワンモーターにより２１０ｒｐｍにて十分に攪拌した後、脱イオン水１３３部を加え、さらに攪拌を行い、温度を２３℃に調製した。ついで、同条件下で１３３部の脱イオン水を滴下して転相乳化により微粒子分散体を作製した。この時の攪拌翼の周速は０．７１ｍ／ｓであった。次に、脱イオン水２７９部を加えて（１規定アンモニア水と水の総量が５９３部となる量の脱イオン水量）溶剤量を調整した。
（合一工程）
次いで、アニオン型乳化剤であるエマール０（花王社製）の２．８部を水３０部に希釈して添加した。その後、温度を２５℃に、また回転数を１５８ｒｐｍに調整し、５．２％の硫酸アンモニュウムの水溶液を粒径が５．５μｍに成長するまで滴下し、その後、同条件で粒径が７μｍに成長するまで攪拌を続け合一操作を終了した。この時の硫酸アンモニュウムの添加量は２５０部であった。また、攪拌翼の周速は０．５４ｍ／ｓであった。得られた粒子を４００倍の光学顕微鏡で観察したところ、粗大粒子、微粒子が共存し粒度分布はブロードであった。また、粗大粒子の中には離型剤微粒子と推測される微粒子の凝集体が露出しているものも観察された。
その後、減圧下に有機溶剤と水の一部を留去し、固液分離、洗浄後、乾燥してトナー粒子を得た。
【０１０３】
以上のようにして得られた各実施例および比較例のトナーの評価結果を表３に示した。
トナーの粒度分布等の評価は、コールター社製マルチサイザーＴＡＩＩ型（アパーチャーチューブ径：１００μｍ）により行った。また、サンプルは、水２０ｇに対し界面活性剤（エルクリヤー（中外写真薬品（株）製））０．１ｇを添加し、更に試料であるトナー０．０４ｇを添加し、超音波分散機でトナー粒子を水中に懸濁させた後、測定を行った。
【０１０４】
【表３】

【０１０５】
実施例、比較例の結果を見ると、ミルベース作製工程まででは離型剤微粒子は均一に系内に分散しているが、転相乳化工程及び合一工程でトナー粒子化する過程で、高圧ホモジナイザーで処理するか否かにより、得られるトナーの性状が大きく影響を受けることがわかる。これは、転相乳化により媒体が有機相から水相へ変化するときに、離型剤粒子の分散安定性が影響を受けるためで、この安定性を保持させるためには高圧ホモジナイザーによる処理が有効であることがわかる。
【０１０６】
【発明の効果】
以上説明したように、本発明の静電荷像現像用トナーの製造方法によれば、ワックスなどの離型剤が微粒子状となって内部に均一に分散し、表面にほとんど露出しないトナー粒子が製造できる。また、得られたトナー粒子は、その粒度分布がシャープなものとなる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a toner for developing an electrostatic charge image that is suitably used in a copying machine, a printer, a fax machine, and the like, and further used in a toner jet type printer.
[0002]
[Prior art]
In recent years, in copiers, printers, fax machines, etc., there are the following needs for toners to further improve the quality of printed images, or to reduce machine cost, size, power and resources. It is growing.
(1) Improved resolution and gradation of printed images by reducing the toner particle size, thinning the toner layer, reducing waste toner amount, and reducing toner consumption per page
(2) Reduction of power consumption by lowering the fixing temperature
(3) Simplification of machine by oilless fixing
(4) Improvement of hue, transparency and gloss in full-color images
(5) Reduction of harmful VOCs (volatile organic compounds) during toner fixing
Etc.
[0003]
Although it is basically possible to reduce the particle size of toner by the pulverization method that has been used for a long time, (1) separation of organic pigments, wax, etc. exposed on the toner particle surface as the particle size is reduced. Charge control becomes difficult due to an increase in the proportion of the mold, (2) powder flowability is deteriorated because the toner particles are indefinite, and (3) energy costs required for production increase. As a result, it is practically difficult to sufficiently satisfy the above-described needs with the toner produced by the pulverization method.
[0004]
On the other hand, many toners are used in which a black organic pigment such as carbon black is dispersed in a binder resin. Recently, cyan, magenta, yellow or other chromatic pigments are used as binders. The amount of color toner dispersed in the resin is increasing.
[0005]
Such color toners have vivid color developability in the printed image and a clear color with no color turbidity due to excellent transparency in color superposition when multicolor printing is performed. There is a demand for print image characteristics that have reproducibility or that enable printing with resolution and gradation equivalent to those of offset printing.
[0006]
Against this background, toners have been actively developed by a polymerization method or an emulsification dispersion method. In particular, the emulsification dispersion method can easily cope with the reduction in the particle size and spheroidization of the toner, and in addition, compared with the polymerization method, (1) the selection range of the binder resin type is widened. (2) Residual monomer This is advantageous in that it can be easily reduced, and (3) the concentration of the organic pigment can be arbitrarily changed from a low concentration to a high concentration, and is also advantageous in the production of color toners.
[0007]
Examples of the production method by such emulsification dispersion include JP-A-10-020552 and JP-A-11-007156 (hereinafter referred to as A patent group). In the manufacturing method according to the A patent group, a binder resin and an organic pigment are dispersed or dissolved in an organic solvent to obtain a colored resin solution, and the colored resin solution is emulsified and dispersed in water to form fine particles of the colored resin solution. The fine particles are agglomerated and further heated and fused to form an aggregate to form toner particles.
[0008]
Other manufacturing methods are disclosed in JP-A-10-147649, JP-A-10-319639, etc. (hereinafter referred to as B patent group). In this B patent group, a binder resin and an organic pigment are dispersed or dissolved in an organic solvent to obtain a colored resin solution, and this colored resin solution is emulsified and dispersed in water to form fine particles of the colored resin solution. The toner particles are produced by agglomeration and fusion in a process to form a unity.
The toner production methods shown in these A patent group and B patent group are said to have an advantage that a spherical toner can be produced with a sharp particle size distribution.
By the way, in the heat roller fixing method, in order to enable oil-less fixing and to give the toner particles good triboelectric chargeability, the surface of the toner particles is not made of a wax such as polypropylene wax or polyethylene wax. It is necessary to uniformly disperse the release agent to be formed as particles having a particle diameter of about 1 μm and to encapsulate them.
[0009]
In the toner manufacturing methods disclosed in the A and B patent groups described above, a method for uniformly dispersing a release agent such as wax in the toner particles is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-91066. As shown in the figure, the release agent and dispersant are finely divided with an organic solvent in advance by a pulverization stirrer such as a ball mill, and dispersed to form a release agent dispersion, which is then added with a dispersion containing a binder resin and an organic pigment, and colored. There is a resin solution.
However, in this method, the dispersion stability of the microparticulated release agent is not sufficient, and it tends to aggregate. When this release agent fine particle having the cohesiveness is used in the manufacturing methods of the A and B patent groups, it can be obtained. The particle size distribution of the toner to be produced becomes wide, and there is a risk that toner particles in which the release agent fine particles are present not on the inside but on the surface are generated.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-020552 (Example)
[Patent Document 2]
JP-A-11-007156 (14th and 23rd paragraphs)
[Patent Document 3]
JP 10-147649 A (24th paragraph, 25th paragraph, Examples)
[Patent Document 4]
Japanese Patent Laid-Open No. 10-319639 (paragraph 62, Example)
[Patent Document 5]
JP 2002-91066 A (Claims)
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and an object of the present invention is to release wax or the like in the toner particles when the toner is produced by the emulsification dispersion method shown in the A patent group and the B patent group. The object is to obtain a production method in which the particles of the mold agent are uniformly dispersed, are not exposed on the surface, have a narrow particle size distribution, and have a uniform particle size.
[0012]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found a method for producing a toner for developing an electrostatic image capable of solving the above-mentioned problems, and have completed the present invention.
That is, in the present invention, a release resin and a binder resin having a carboxyl group are pre-dispersed in an organic solvent to obtain a pre-fine dispersion, and this pre-fine dispersion is treated with a high-pressure homogenizer to stabilize the release agent. In this dispersion, a binder resin having a carboxyl group and an organic pigment are added to this fine release agent stable fine dispersion and dissolved or dispersed to form a colored resin solution, and a basic compound is added to this colored resin solution to obtain this colored resin solution. Emulsified in an aqueous medium, fine particles of a colored resin solution are formed in the aqueous medium, and then a dispersion stabilizer and an electrolyte are sequentially added to form an integrated unit of the fine particles. An object of the present invention is to provide a method for producing a toner for developing an electrostatic charge image, wherein after removing the solvent, the combined unit is separated from the aqueous medium and dried.
[0013]
In the present invention, a release agent and a binder resin having a carboxyl group are pre-dispersed in an organic solvent to prepare a pre-fine dispersion, and this pre-fine dispersion is treated with a high-pressure homogenizer to stabilize the release agent. In this dispersion, a binder resin having a carboxyl group and an organic pigment are added to this fine release agent stable fine dispersion and dissolved or dispersed to form a colored resin solution, and a basic compound is added to this colored resin solution to obtain this colored resin solution. After emulsification in an aqueous medium, fine particles of a colored resin solution are formed in the aqueous medium, and after removing the organic solvent in the fine particles, an aggregate of the fine particles is formed by adding an electrolyte. Provided is a method for producing a toner for developing an electrostatic image, wherein the aggregate is heated and fused to form an aggregate, and the aggregate is separated from the aqueous medium and dried. It is intended.
[0014]
In the present invention, a release resin and a binder resin having a carboxyl group are pre-dispersed in an organic solvent to obtain a pre-fine dispersion, and this pre-fine dispersion is treated with a high-pressure homogenizer to thereby form release agent particles. The binder resin having a carboxyl group is adsorbed on the surface, and due to steric repulsion in the organic phase, and becomes electrically stable in an aqueous medium, the release agent particles do not aggregate and are in a stable dispersion state. Can be maintained. For this reason, the release agent particles are not aggregated in the subsequent steps, particularly the emulsification step and the coalescence step, and are uniformly encapsulated in the toner particles while maintaining the dispersed state. Further, the sharp particle size distribution of the toner, which is the original characteristic of the emulsification dispersion method, is not impaired.
[0015]
In the present invention, a toner production method in which the aggregation and coalescence of fine particles containing an organic solvent produced by emulsification and dispersion are performed in one step is referred to as a production method by “unification”. Saying together. Further, after removing the organic solvent in the fine particles produced by emulsification and dispersion, the fine particles are aggregated, and then the production method of fusing the aggregates by heating to coalesce the fine particles is called a production method by “association”. The particles formed by the method are called “aggregates”.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail. The production method of the present invention comprises the following steps.
First step: A release resin and a binder resin having a carboxyl group are pre-dispersed in an organic solvent to prepare a pre-fine dispersion, and this is treated with a high-pressure homogenizer to be homogenized and stabilized. The process of
Second step: A colored resin solution is prepared by dissolving or dispersing a binder resin having a carboxyl group and an organic pigment in this release agent-stable fine dispersion, and then adding a basic compound to the colored resin solution in an aqueous medium. A step of forming fine particles of a colored resin solution in an aqueous medium by emulsifying
Third step: combining the fine particles to produce a combined solid, removing the organic solvent contained in the integrated, or removing the organic solvent in the fine particles, and then associating the fine particles to form an aggregate Manufacturing process
Fourth step: A step of producing a toner by separating the combined or aggregate after solvent removal from an aqueous medium and drying.
The above four steps. However, these steps are divided for convenience of explanation, and are not strictly divided, and may be continuously performed over two steps depending on a specific embodiment.
[0017]
First, the first step will be described in detail.
There is no particular limitation on the method for pre-dispersing the release agent and the binder resin having a carboxyl group (hereinafter sometimes simply referred to as a binder resin) in an organic solvent. For example, (1) a mold release agent and a binder resin are melted and kneaded by a kneader, a roll, an extrusion kneader or the like to obtain a master chip. Next, the master chip is dissolved and dispersed in an organic solvent by a mixing stirrer such as Desper. At this time, a binder resin may be added. (2) At the time of synthesis (polymerization) of the binder resin, a release agent is added, and both are melted and dispersed during the synthesis reaction to form a master chip, which is then mixed into an organic solvent by a mixing stirrer such as a desper. Dissolve and disperse, and finely disperse with a stirrer using media such as a ball mill and a sand mill. (3) The binder resin and the release agent are dissolved and dispersed in an organic solvent by a mixing stirrer such as Desper, and further finely dispersed by a stirrer using a medium such as a ball mill and a sand mill.
[0018]
Thus, the preliminary fine dispersion obtained by preliminary fine dispersion is then homogenized and stabilized by a high-pressure homogenizer. As the high-pressure homogenizer used here, “Microfluidizer” (manufactured by Microfluidizer, registered trademark), “Nanomizer” (registered trademark, manufactured by Nanomizer), “HV-0H-07-3.7SS type” ( (Made by Izumi Food Machinery Co., Ltd.) is used, and the processing conditions are a temperature of 20 ° C. to the boiling point of the medium used, a pressure of 10 to 100 MPa, and a processing frequency of about 1 to 5 times. In the treatment with the high-pressure homogenizer, there is almost no pulverizing action of the release agent particles, and the dispersion stability of the preliminary fine dispersion is mainly improved.
By treatment with this high-pressure homogenizer, binder resin molecules having a carboxyl group are adsorbed on the surface of the release agent particles, steric repulsion occurs in the organic phase, and an electrically stable electric double layer is formed in an aqueous medium. It becomes an electrically stable state and loses cohesiveness. Even if it aggregates, it can be easily dissociated into primary particles by applying a slight external force. For this reason, the binder resin having a carboxyl group also serves as a dispersion stabilizer for the release agent particles.
By this high-pressure homogenizer treatment, a release agent stable fine dispersion can be obtained. The average particle size of the release agent particles in the obtained release agent stable differential acid solution is in the range of 0.3 to 2.0 μm. Moreover, in the release agent stable fine dispersion, the mass ratio of the release agent and the binder resin is in the range of release agent / binder resin = 10/90 to 50/50, and the ratio of the solid content to the organic solvent is Solid content / organic solvent = 30/70 to 50/50.
[0019]
The release agent used in the production method of the present invention is a group of hydrocarbon waxes such as polypropylene wax, polyethylene wax and Fischer-Tropsch wax, natural ester waxes such as synthetic ester wax, carnauba wax and rice wax. A release agent selected from among the above is used. Among them, natural ester waxes such as carnauba wax and rice wax, synthetic ester waxes obtained from polyhydric alcohols and long-chain monocarboxylic acids, and synthetic hydrocarbon waxes such as Fischer-Tropsch wax, which have a sharp endothermic peak at low temperatures. Are preferably used.
The melting point of the wax is not particularly limited, but is preferably 150 ° C. or less from the viewpoint of offset resistance, and is preferably in the range of 50 to 130 ° C. from the viewpoint of low-temperature fixability and storage stability.
[0020]
The binder resin used in the present invention is a binder resin containing a carboxyl group. This binder resin having a carboxyl group is a binder resin that becomes self-water-dispersible by neutralizing the carboxyl group in an emulsifying and dispersing step to be described later (hereinafter sometimes referred to as self-water-dispersible resin). When the carboxyl group is neutralized with a basic compound, it becomes an anionic type. As a result, the hydrophilicity of the resin is increased, and the resin can be stably dispersed in the aqueous medium without using a dispersion stabilizer or a surfactant. The acid value of the self-water dispersible binder resin is preferably 3 to 20, and an acid value of less than 3 is not preferable because stable fine particles cannot be formed in the emulsification dispersion process. If it exceeds 20, the hygroscopicity after the toner is produced is increased, which adversely affects the charging characteristics. The binder resin will be described in more detail later.
[0021]
Examples of the organic solvent for dissolving or dispersing the binder resin, the release agent, and further the organic pigment, additive, etc. include hydrocarbons such as pentane, hexane, heptane, benzene, toluene, xylene, cyclohexane, petroleum ether, and the like. Halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, carbon tetrachloride; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate are used. It is done. These solvents can be used in combination of two or more, but from the viewpoint of solvent recovery, it is preferable to use the same type of solvent alone. The organic solvent is preferably one that dissolves or disperses the binder resin, has a relatively low toxicity, and has a low boiling point that can be easily removed in a subsequent step. As such a solvent, methyl ethyl ketone is most preferable.
[0022]
Next, the second step will be described.
First, the dispersion liquid (A) containing additives such as a binder resin, an organic pigment, and a charge control agent is added to and mixed with the release agent stable fine dispersion liquid obtained in the first step, and a colored resin solution (hereinafter referred to as a colored resin solution) , Sometimes referred to as a mill base). The binder resin in this dispersion liquid (A) is a binder resin for the toner particles obtained together with the binder resin contained in the above-mentioned release agent stable fine dispersion liquid. Therefore, from the total amount of the binder resin forming the toner particles. An amount obtained by subtracting the binder resin contained in the release agent stable fine dispersion may be used.
The dispersion (A) can be produced by, for example, (a) using a pressure kneader, a heated two-roll, twin-screw extruder kneader, or the like containing a mixture containing various additives such as a binder resin, an organic pigment, and a charge control agent. The chip is kneaded by heating to a temperature not lower than the softening point of the resin used and not higher than the thermal decomposition temperature. At this time, the organic pigment or the like may be melt-kneaded as a master batch. Thereafter, the kneaded chips obtained are prepared by dissolving or dispersing in an organic solvent with a stirrer such as a desper. (B) Various additives such as a binder resin, an organic pigment, a release agent, and a charge control agent are mixed with an organic solvent, and this is wet kneaded by a stirrer using a medium such as a ball mill or a sand mill. In this case, organic pigments, additives, and the like may be mixed after preliminary dispersion separately in advance.
[0023]
Specific means of the method (b) include a resin solution in which a binder resin is previously dissolved in an organic solvent in a mixing / dispersing machine using a medium such as a ball mill, a bead mill, a sand mill, or a continuous bead mill, and an organic Add a pigment or additive, stir and disperse it into a master batch, and further mix a binder resin for dilution and an additional organic solvent to disperse the organic pigment or additive in the organic solvent (A ). At this time, rather than putting the organic pigment and additive untreated directly into a mixing / dispersing machine such as a ball mill, a low-viscosity binder resin and organic pigment or additive are previously applied in a pressure kneader and heated two rolls. It is preferable to use a master batch obtained by kneading and dispersing. According to the production method (b) as described above, since the polymer component (gel component) of the binder resin is not cut, it is preferable to the method (a) in which the binder resin is dispersed by melt kneading.
[0024]
The dispersion liquid (A) thus prepared is added to the release agent stable fine dispersion liquid and mixed to obtain a colored resin solution (mill base).
Further, as another method for producing the colored resin solution, the remaining binder resin, organic pigment, additive, and additional organic solvent are added to the release agent stable fine dispersion, and the mixture is stirred with a mixing stirrer such as a desper, There is also a method of wet-stirring with a stirrer using a medium such as a ball mill or a sand mill to obtain a colored resin solution (mill base).
[0025]
Next, the colored resin solution is emulsified and dispersed in an aqueous medium. In this emulsified dispersion, (A) a method of emulsifying the colored resin solution in an aqueous medium in the presence of a basic compound, or (B) Fine particles of the colored resin solution can be formed in the aqueous medium by a method of adding the aqueous medium to the colored resin solution in the presence of a basic compound. The fine particles of the colored resin solution are preferably formed by the method (B), and the particle size distribution of the fine particles of the colored resin solution becomes sharp.
[0026]
In emulsification and dispersion, a method of gradually adding an aqueous medium (water or a liquid medium containing water as a main component) to the colored resin solution is preferable. In that case, a water-in-oil discontinuous phase is formed by gradually adding an aqueous medium to the organic continuous phase of the colored resin solution, and further adding an aqueous medium to add Oil-in Water. In this way, a suspension / emulsion is formed in which the colored resin solution floats as particles (droplets) in an aqueous medium (hereinafter, this method is referred to as phase inversion emulsification).
[0027]
In the phase inversion emulsification, the aqueous medium is added so that the ratio of the aqueous medium to the total amount of the organic solvent and the added aqueous medium is 30 to 80% by mass. More preferably, it is 35-70 mass%, and it is especially preferable that it is 40-70 mass%. The aqueous medium used is preferably water, more preferably deionized water.
[0028]
The basic compound used for emulsification is not particularly limited, and for example, inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine are used. Of these, inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide are preferred. In order to disperse the binder resin in the aqueous medium, there is a method of adding a dispersion stabilizer such as a suspension stabilizer or a surfactant. However, in the method of adding a suspension stabilizer or a surfactant and emulsifying it, A high shear force is required. As a result, the generation of coarse particles and the particle size distribution become broad, which is not preferable. Therefore, in the present invention, a self-water dispersible resin is used, and dispersion stability is obtained by neutralizing the carboxyl group of the resin with a basic compound.
[0029]
Examples of the method of neutralizing the carboxyl group of the binder resin with a basic compound include, for example, (1) a method in which the colored solution is prepared and then neutralized with a basic compound, or (2) basic in advance in an aqueous medium. The method of mixing the compound and neutralizing the carboxyl group of the binder resin contained in the colored resin solution when performing phase inversion emulsification may be mentioned.
[0030]
The basic compound is used in an amount of 1 to 3 equivalents based on the total amount of carboxyl groups in the binder resin. More preferably, it is more than 1 equivalent and 2 equivalents or less. By adding in excess of the amount required to neutralize the carboxyl group of the binder resin in this way, it is possible to prevent the formation of irregularly shaped particles, improve the sphericity of the toner, The particle size distribution can be sharpened.
When the amount of the basic compound used is less than 1 equivalent with respect to the total amount of carboxyl groups of the binder resin, it is not preferable because irregularly shaped particles are generated. On the other hand, if it exceeds 3 equivalents, the fine particles are likely to coalesce and the generation of coarse particles increases, which is not preferable.
[0031]
In phase inversion emulsification, homomixer (Special Machine Industries Co., Ltd.), or Thrasher (Mitsui Mining Co., Ltd.), Cavitron (Eurotech Co., Ltd.), Microfluidizer (Mizuho Industry Co., Ltd.), Menton Gorin homogenizer (Gorin Inc.) ), Nanomizer (Nanomizer Co., Ltd.), Static Mixer (Noritake Company), etc., high share emulsifying disperser, continuous emulsifying disperser and the like can be used.
[0032]
However, rather than using the above-described high shear emulsifying disperser, for example, an agitator, an anchor blade, a turbine blade, a fiddler blade, a full zone blade, a max blend blade, a half moon as disclosed in JP-A-9-114135 It is preferable to use a wing or the like. Among these, a large wing excellent in uniform mixing properties such as a Max blend wing and a full zone wing is more preferable. The peripheral speed of the stirring blade in the emulsification step (phase inversion emulsification step) for forming fine particles of the mixture in the aqueous medium is preferably 0.2 to 10 m / s, and is low as less than 0.2 to 8 m / s. A method of dropping water while stirring with a shear is more preferable. Most preferably, it is 0.2-6 m / s. When the peripheral speed of the stirring blade is faster than 10 m / s, the dispersion diameter at the time of phase inversion emulsification becomes large, which is not preferable. On the other hand, when the peripheral speed is lower than 0.2 m / s, the stirring is not uniform, phase inversion does not occur uniformly, and coarse particles tend to be generated, which is not preferable. Moreover, the temperature at the time of phase inversion emulsification is not particularly limited, but the higher the temperature, the more coarse particles are generated, which is not preferable. On the other hand, when the temperature is too low, the viscosity of the mixture containing the binder resin and the organic solvent is increased, and the generation of coarse particles is increased. The temperature range during phase inversion emulsification is preferably 10 to 40 ° C. More preferably, it is the range of 20-30 degreeC.
[0033]
The 50% volume average particle size of the fine particles of the colored resin solution emulsified in the second step is more than 1 μm and not more than 6 μm, more preferably more than 1 μm and 4 μm. If it is 1 μm or less, the release agent, organic pigment, and the like are not sufficiently encapsulated by the binder resin, which adversely affects charging characteristics and development characteristics. If the particle size is large, the particle size of the obtained toner is limited. Therefore, it is necessary to make the particle size smaller than that of the target toner. However, if the particle size exceeds 6 μm, coarse particles are likely to be generated. Therefore, it is not preferable. The particle size distribution of the fine particles of the colored resin solution emulsified in the second step is such that the volume particle size ratio of 10 μm or more is 1% or less, more preferably 0.5% or less, and the volume particle size of 5 μm or more. The ratio is 3% or less, more preferably 1% or less.
[0034]
Next, the third step will be described. In the third step, the fine particles of the colored resin solution obtained in the second step are united or associated to form a unity or aggregate of the microparticles, thereby forming toner particles having a desired particle size. The manufacturing method by the union method and the manufacturing method by the association method will be explained in order.
[0035]
In the coalescence method, the dispersion of fine particles of the colored resin solution obtained in the second step is diluted with water to adjust the amount of solvent. Thereafter, a dispersion stabilizer is added and coalescence is advanced by dropping an aqueous electrolyte solution in the presence of the dispersion stabilizer to obtain an aggregate having a predetermined particle diameter.
[0036]
The fine particles of the colored resin solution obtained in the second step are stably dispersed in the aqueous medium by the action of the electric double layer of the binder resin having a carboxyl group. In the third step, the particles are destabilized by adding an electrolyte for destroying or reducing the electric double layer to the aqueous medium in which the fine particles are dispersed. Examples of the electrolyte here include acidic substances such as hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, and oxalic acid. In addition, organic and inorganic water-soluble salts such as sodium sulfate, ammonium sulfate, potassium sulfate, magnesium sulfate, sodium phosphate, sodium dihydrogen phosphate, sodium chloride, potassium chloride, ammonium chloride, calcium chloride, sodium acetate, etc. It can be used effectively as an electrolyte. These electrolytes may be used alone or in combination of two or more substances. Among them, monovalent cation sulfates such as sodium sulfate and ammonium sulfate are preferable for promoting uniform coalescence. In the production method of the present invention, the fine particles obtained in the second step are swollen by the solvent, and the electric double layer of the particles is in an unstable state contracted by the addition of the electrolyte, so that the low shear (low shear) The coalescence easily proceeds even when the particles collide with each other by the agitation of force.
[0037]
By the way, only by adding an electrolyte or the like, the dispersion stability of the fine particles in the system becomes unstable, so the coalescence becomes non-uniform and coarse particles and aggregates are generated. In order to prevent agglomerates of fine particles produced by electrolytes or acidic substances from repeating reunion and forming aggregates larger than the target particle size, before adding electrolytes etc., hydroxyapatite It is necessary to add an inorganic dispersion stabilizer such as ionic or nonionic surfactant as a dispersion stabilizer. The dispersion stabilizer to be used is required to have a property capable of maintaining dispersion stability even in the presence of an electrolyte added later. Examples of the dispersion stabilizer having such characteristics include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester. , Polyoxyethylene sorbitan fatty acid esters and the like, or nonionic emulsifiers such as various pluronics, alkyl sulfate ester salt type anionic emulsifiers, and quaternary ammonium salt type cationic dispersion stabilizers. Among these, even if a small amount of anionic or nonionic dispersion stabilizer is added, the dispersion stability of the system is effective, which is preferable. The cloud point of the nonionic surfactant is preferably 40 ° C. or higher. The surfactants described above may be used alone or in combination of two or more. By adding an electrolyte in the presence of such a dispersion stabilizer (emulsifier), it becomes possible to prevent non-uniform coalescence, and as a result, a sharp particle size distribution is obtained. Improvement is achieved.
[0038]
Further, in order to promote uniform coalescence, the temporary stirring conditions are important. The types of stirring blades and stirring conditions that can be preferably used are the same as described above. Under the above conditions, coalescence proceeds only by collision of fine particles, and the coalescence does not dissociate and disperse again. In particular, in the coalescence method, coalescence proceeds preferentially from fine particles, so that generation of ultrafine particles is small and a sharp particle size distribution is achieved, so that an improvement in yield can be achieved.
[0039]
In the case of producing a unity, it is preferable to further dilute the fine particle dispersion obtained by phase inversion emulsification in the second step with water. Thereafter, a dispersion stabilizer and an electrolyte are sequentially added to perform coalescence. Alternatively, it is preferable to adjust the amount of the solvent in the dispersion by adding an aqueous solution of a dispersion stabilizer and / or an electrolyte to obtain particles having a predetermined particle diameter. The amount of the solvent contained in the system before adding the electrolyte is preferably in the range of 15 to 45% by mass. Moreover, the inside of the range of 18-30 mass% is more preferable, and especially the inside of the range of 20-25 mass% is preferable. If the amount of solvent is less than 15% by mass, the electrolytic mass required for coalescence increases, which is not preferable. On the other hand, when the amount of the solvent exceeds 45% by mass, the generation of aggregates due to non-uniform coalescence increases, and the amount of dispersion stabilizer added increases, which is not preferable.
[0040]
In this step, the shape of the toner particles after coalescence can be controlled by adjusting the amount of solvent contained in the fine particles obtained by phase inversion emulsification. When the amount of the solvent is in the range of 20 to 45% by mass, the degree of swelling of the fine particles by the solvent is large, so that spherical to substantially spherical particles can be easily obtained by coalescence. On the other hand, when the amount of the solvent is in the range of 15 to 20% by mass, the degree of swelling of the fine particles by the solvent is small, so that irregularly to substantially spherical toner particles can be easily obtained.
[0041]
The amount of the dispersion stabilizer used is preferably in the range of 0.1 to 3.0% by mass with respect to the solid content of the fine particles, for example. The inside of the range of 0.3-2.0 mass% is more preferable, and the inside of the range of 0.3-1.5 mass% is especially preferable. If it is less than 0.1% by mass, the desired effect of preventing the generation of coarse particles cannot be obtained. On the other hand, if the amount exceeds 3.0% by mass, coalescence does not proceed sufficiently even if the amount of the electrolyte is increased, and particles having a predetermined particle diameter cannot be obtained. As a result, fine particles remain and the yield is reduced. Since it lowers, it is not preferable.
[0042]
Moreover, it is preferable that the quantity of the electrolyte to be used exists in the range of 0.5-15 mass% with respect to solid content content of microparticles | fine-particles. It is more preferably within a range of 1 to 12% by mass, and particularly preferably within a range of 1 to 10% by mass. If the amount of the electrolyte is less than 0.5% by mass, the coalescence does not proceed sufficiently, which is not preferable. On the other hand, when the amount of the electrolyte exceeds 15% by mass, coalescence becomes non-uniform, and aggregates and coarse particles are generated and the yield is lowered.
[0043]
The temporary temperature is preferably in the range of 10 to 50 ° C. More preferably, it exists in the range of 20-40 degreeC, and it is especially preferable that it is 20-35 degreeC. If the temperature is less than 10 ° C., coalescence is difficult to proceed. On the other hand, when the temperature exceeds 50 ° C., the coalescence rate is increased, and aggregates and coarse particles are easily generated, which is not preferable. In the manufacturing method of this invention, the unification | combination production | generation by unification is possible on low temperature conditions, such as 20-40 degreeC, for example.
[0044]
By the way, in order to keep the frictional charging performance of the toner particles satisfactorily, it is necessary to prevent the organic pigment, release agent, additive and the like from being exposed on the surface of the toner particle, that is, organic pigment, release agent, addition and the like. It is necessary to have a toner structure encapsulated in the toner particles. The deterioration in chargeability associated with the reduction in the toner particle size is caused by the fact that part of the organic pigment, release agent, and additive contained is exposed on the toner particle surface. That is, even when the content (% by mass) of the organic pigment, the release agent, the additive, etc. is the same, the surface area of the toner particle is increased by reducing the particle size, and the organic pigment, the release agent exposed on the surface of the toner particle As a result, the ratio of the agent, additive, etc. increases, and as a result, the composition of the toner particle surface changes greatly, and the triboelectric charging performance of the toner particles changes greatly, making it difficult to obtain appropriate chargeability.
[0045]
The toner particles produced according to the present invention are characterized in that an additive such as an organic pigment, a release agent, or a charge control agent is included in a binder resin. Whether the organic pigment, the release agent, or the like is not exposed on the toner particle surface can be easily determined by, for example, observing the cross section of the particle with a TEM (transmission electron microscope). More specifically, the toner particles are embedded in a resin and the cross section cut with a microtome is dyed with ruthenium oxide, if necessary, and observed with a TEM. Organic pigments, release agents, etc. are encapsulated in the toner particles. It can be confirmed that the particles are almost uniformly dispersed.
[0046]
The unitary shape obtained in the third step can be changed from an indeterminate shape to a spherical shape depending on the degree of unity. For example, it can be changed from 0.94 to 0.99 in terms of average circularity. The average circularity can also be obtained by taking a SEM (scanning electron microscope) photograph of the finally obtained toner particles, measuring and calculating it, and the like, manufactured by Toa Medical Electronics Co., Ltd. Since the flow type particle image analyzer FPIP-1000 can be easily obtained, the value measured by this apparatus is used as the average circularity.
[0047]
The shape of the toner particles is substantially spherical or spherical with an average circularity of 0.97 or more, so that powder fluidity and transfer efficiency are improved. It is preferable.
[0048]
The flow-type particle image analyzer FPIP-1000 is an apparatus that captures the size and shape of fine particles such as toner particles, and particle imaging is performed as follows.
First, a sample is prepared by suspending toner particles in water containing a small amount of a surfactant. Next, this sample is allowed to flow down into a transparent and flat cell provided in the flow type particle image analyzer FPIP-1000. A light source that emits pulsed light is installed on one side of the cell, and an imaging camera is provided on the opposite side of the cell so as to face the light source. The toner particles in the sample flowing down in the cell of the FPIP-1000 are captured as a still image by a camera facing the light source while holding the cell when irradiated with pulsed light.
[0049]
Based on the image of the toner particle thus captured, the contour of each toner particle is extracted by the image analysis device, and the projected area and peripheral length of the toner particle image (peripheral length of the toner particle projected image) are calculated. The Further, from the calculated projected area of the toner particle image, the circumference of a circle having the same area (the circumference of the circle having the same area as the toner particle projected area) is calculated. The average circularity is obtained by dividing the circumference of the circle having the same area as the toner particle projection area calculated in this way by the circumference of the toner particle projection image.
[0050]
The conditions when measuring with the above apparatus are as follows.
(1) Preparation of toner particle suspension
0.1 g of surfactant (ELCLEAR (manufactured by Chugai Photo Chemical Co., Ltd.)) is added to 20 g of water, 0.04 g of toner as a sample is further added, and the toner particles are suspended in water with an ultrasonic disperser. Make it cloudy.
(2) Measurement conditions
Measurement temperature: 25 ° C
Measuring humidity: 60%
Number of measured toner particles: 5000 ± 2000
[0051]
After coalescing the fine particles of the colored resin solution, the solvent is removed. The method for removing the solvent is not limited at all, and it is carried out under normal pressure or reduced pressure. In order to remove the solvent quickly under a low temperature condition, it is preferably carried out under reduced pressure.
[0052]
Next, the meeting method will be explained. In the association method, first, the organic solvent contained in the fine particles of the colored resin solution obtained in the second step is removed. In this solvent removal step, it is not necessary to completely remove the organic solvent, and it is preferable to remove 60 to 98% of the used organic solvent. Moreover, it is more preferable to remove 70 to 95%, and it is particularly preferable to remove 80 to 95%. By leaving a part of the organic solvent, the operation of the agglomeration / fusion process of fine particles performed in the next step is facilitated, and particles having a desired particle shape can be produced. For example, there are spherical aggregates in which the fusion has progressed to such an extent that the aggregated resin particles do not retain their shape, or irregular aggregates that do not substantially collapse the aggregated microparticles.
[0053]
In addition, if the amount of the organic solvent remaining in the fine particles is large, coarse particles are likely to be generated at the time of agglomeration and fusion. If the amount of the residual organic solvent is small, the fusion operation takes time or the fusion temperature is increased. This is not preferable because coarse particles are likely to be generated. The remaining organic solvent is completely removed after the association.
[0054]
In the association method, the dispersion of fine particles of the colored resin solution obtained in the second step is diluted with water to adjust the solid content. Thereafter, the aqueous solution of the electrolyte is dropped to advance the association, thereby obtaining an aggregate having a predetermined particle size. In that case, it is preferable to carry out the association by adding a dispersion stabilizer. As solid content before dropping aqueous solution of electrolyte, the range of 10-30 mass% is preferable. If the amount is less than 10% by mass, the yield of the kettle is greatly reduced, which is not preferable. On the other hand, if it is more than 30% by mass, it is difficult to produce aggregates having a uniform size. The electrolyte and dispersion stabilizer used can be the same as those used for coalescence. The aggregated particles are fused by heating the entire aqueous medium in which the aggregates are dispersed above the glass transition point of the binder resin. The fusion is performed at 60 to 100 ° C, more preferably at 70 to 90 ° C.
[0055]
The aggregate produced by the association method is characterized in that an organic pigment, a release agent, an additive and the like are in the form of particles and are encapsulated in particles made of a binder resin, as in the case of the integration. Further, the shape of the aggregate can be changed from an indeterminate shape to a spherical shape depending on the conditions during the meeting. For example, it can be changed from 0.94 to 0.99 in terms of average circularity. In order to improve the sphericity, the fusion may be performed for a long time at a higher temperature.
[0056]
Next, the fourth step will be described. In the fourth step, the unity or aggregate obtained in the third step is separated from the aqueous medium and dried. Separation from the aqueous medium can be performed by a known and commonly used means such as a centrifugal separator, a filter press, a belt filter or the like. Subsequently, the toner particles can be obtained by drying the particles. Toner particles produced using an emulsifier or a dispersion stabilizer are preferably washed more thoroughly.
[0057]
As the drying method, any known and commonly used method can be employed. For example, a method in which the toner particles are dried at normal or reduced pressure at a temperature at which the toner particles are not thermally fused or agglomerated, a method of freeze-drying, and the like. It is done. Another example is a method of simultaneously separating and drying toner particles from an aqueous medium using a spray dryer or the like. In particular, a method in which powder is stirred and dried under reduced pressure while heating at a temperature at which toner particles are not thermally fused or agglomerated, or a flash jet drier that instantly dries using a heated and dried air stream (Seishin Corporation) Etc.) is efficient and preferable.
[0058]
In the toner particles thus produced, the particulate release agent is uniformly dispersed inside the particles made of the binder resin, and the release agent is exposed on the particle surface. It is not in a state. If the content of the release agent in the toner particles is less than 1% by mass, the releasability tends to be insufficient, and if it exceeds 40% by mass, the wax tends to be exposed on the surface of the toner particles, and the chargeability and storage stability are improved. In the range of 1 to 40% by mass, the properties are likely to be lowered.
[0059]
With respect to the particle size distribution of the toner obtained by the production method of the present invention, 50% volume particle size / 50% number particle size (Dv / Dn) is 1 as measured by Coulter Multisizer TAII type (aperture tube diameter: 100 μm). .25 or less, more preferably 1.20 or less. It is preferable that it is 1.25 or less because good images can be easily obtained. Moreover, GSD is preferably 1.30 or less, and more preferably 1.25 or less. The GSD is a value obtained from the square root of (16% volume particle size / 84% volume particle size) as measured by a multisizer TAII type manufactured by Coulter. The smaller the GSD value, the sharper the particle size distribution and the better the image.
[0060]
The toner obtained by the production method of the present invention preferably has a 50% volume average particle diameter (Dv50) in the range of 1 to 13 μm from the viewpoint of image quality to be obtained, and about 3 to 10 μm is the current machine. It is more preferable because it can be easily matched with. For a color toner, a range in which the volume average particle diameter is 3 to 8 μm is preferable. When the volume average particle size is reduced, not only the resolution and gradation are improved, but also the effect that the thickness of the toner layer for forming the printed image is reduced and the toner consumption per page is reduced is preferable.
[0061]
As described above, the binder resin having a carboxyl group used in the present invention is a self-water dispersible resin and can be used without particular limitation as long as it does not impair the object of the present invention. Specifically, vinyl copolymer resins such as polystyrene resin, styrene acrylic resin, or styrene butadiene resin, polyester resin, epoxy resin, butyral resin, xylene resin, coumarone indene resin, etc. may be mentioned. Among these, vinyl copolymer resins and polyester resins are preferable, and a polyester resin having a carboxyl group is particularly preferably used because of a good balance of fixability, offset resistance, transparency, and the like. it can.
[0062]
The polyester resin having a carboxyl group preferably used in the present invention is synthesized by dehydration condensation of a polybasic acid and a polyhydric alcohol.
[0063]
Examples of polybasic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, succinic acid, alkenyl succinic anhydride Aliphatic carboxylic acids such as acid and adipic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polybasic acids can be used alone or in combination of two or more. Of these polybasic acids, aromatic carboxylic acids are preferably used.
[0064]
Examples of the polyhydric alcohol include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, trimethylolpropane, and pentaerythritol; cyclohexanediol and cyclohexanedi Examples thereof include alicyclic diols such as methanol and hydrogenated bisphenol A; aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A. These polyhydric alcohols can be used alone or in combination of two or more. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
[0065]
In addition, monocarboxylic acid and / or monoalcohol is further added to the polyester resin obtained by polycondensation of polycarboxylic acid and polyhydric alcohol to esterify the hydroxyl group and / or carboxyl group at the polymerization terminal. The acid value of the polyester resin can be adjusted. Examples of the monocarboxylic acid used for such purpose include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, and propionic anhydride. Examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, trifluoroethanol, trichloroethanol, hexafluoroisopropanol, and phenol.
[0066]
The polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid are mixed in a reaction vessel equipped with a thermometer, a stirrer, and a flow-down condenser, and heated at 150 to 250 ° C. in the presence of an inert gas such as nitrogen, By removing the by-product low molecular weight compound continuously from the reaction system, when the predetermined physical property value is reached, the reaction is stopped, and cooling is performed, whereby the desired reactant can be obtained.
[0067]
Such a polyester resin can be synthesized by adding a catalyst. Examples of the esterification catalyst used include organic metals such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutyl titanate. Further, when the carboxylic acid component to be used is a lower alkyl ester, a transesterification catalyst can be used. Examples of the transesterification catalyst include metal acetates such as zinc acetate, lead acetate, and magnesium acetate; metal oxides such as zinc oxide and antimony oxide; metal alkoxides such as tetrabutyl titanate and the like. About the addition amount of a catalyst, it is preferable to set it as the range of 0.01-1 mass% with respect to the total amount of a raw material.
[0068]
In such a polycondensation reaction, in order to produce a branched or cross-linked polyester resin, in particular, a polybasic acid having three or more carboxyl groups in one molecule or an anhydride thereof, and / or one molecule What is necessary is just to use the polyhydric alcohol which has a 3 or more hydroxyl group in as an essential synthetic | combination raw material.
[0069]
The glass transition temperature (Tg) of the binder resin having a carboxyl group used in the present invention is preferably 50 ° C. or higher, and particularly preferably the Tg is 55 ° C. or higher. When the Tg is 50 ° C. or less, the toner tends to cause a blocking phenomenon (thermal aggregation) when the toner is stored, transported, or exposed to a high temperature inside the developing device of the machine.
[0070]
Moreover, as a softening point of binder resin, the thing of the range of 90 degreeC-180 degreeC among the 90 degreeC or more is preferable, More preferably, it is the range of 95 degreeC-160 degreeC. When the softening point is less than 90 ° C., the toner tends to cause an agglomeration phenomenon, which tends to cause troubles during storage and printing, and when it exceeds 180 ° C., the fixability often deteriorates.
[0071]
Furthermore, as a full-color toner, particularly when color reproducibility and transparency during color superposition are required, the softening point of the resin is preferably in the range of 90 ° C. to 130 ° C., more preferably 95 It is the range of ° C to 120 ° C.
[0072]
The softening point of the binder resin in the present invention is defined by a T1 / 2 temperature measured using a flow tester CFT-500 manufactured by Shimadzu Corporation, which is a constant load extrusion type capillary rheometer. The measurement condition with a flow tester is a piston cross-sectional area of 1 cm. ² The cylinder pressure was 0.98 MPa, the die length was 1 mm, the die hole diameter was 1 mm, the measurement start temperature was 50 ° C., the temperature increase rate was 6 ° C./min, and the sample mass was 1.5 g.
[0073]
In the present invention, a charge control agent can be used. The positively chargeable charge control agent is not particularly limited, and known and commonly used nigrosine dyes, quaternary ammonium compounds, onium compounds, triphenylmethane compounds and the like can be used for toners. In addition, basic group-containing compounds such as amino groups, imino groups, and N-heterocycles, such as tertiary amino group-containing styrene acrylic resins, are also effective as positively chargeable charge control agents, and as positively chargeable charge control agents. , Alone or in combination with the positively chargeable charge control agent. Depending on the application, a small amount of a negative charge control agent such as an azo dye metal complex or a salicylic acid derivative metal complex salt may be used in combination with the positive charge control agent. In addition, as a negatively chargeable charge control agent, heavy metals such as trimethylethane dye, metal complex salt of salicylic acid, metal complex salt of benzyl acid, copper phthalocyanine, perylene, quinacridone, azo pigment, metal complex azo dye, azochrome complex, etc. Examples thereof include acidic dyes, calixarene type phenol condensates, cyclic polysaccharides, resins containing carboxyl groups and / or sulfonyl groups, and the like.
[0074]
The content of the charge control agent is preferably 0.01 to 10% by mass. It is especially preferable that it is 0.1-6 mass%.
[0075]
There is no restriction | limiting in particular about the organic pigment used for the manufacturing method of this invention, A well-known and usual thing is used. Examples of the black pigment include carbon black, cyanine black, aniline black, ferrite, and magnetite. Examples of blue organic pigments include phthalocyanine C.I. I. Pigment Blue 1, 2, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15, 16, 17: 1, 27, 28, 29, 56, 60, 63, and the like. The blue colorant is preferably C.I. I. Pigment Blue 15: 3, 15, 16, 60, and most preferably C.I. I. Pigment Blue
15: 3,60.
[0076]
Examples of yellow organic pigments include C.I. I. Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 24, 55, 65, 73, 74, 81, 83, 87, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 116, 117, 120, 123, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 156, 168, 169, 170, 171, 172, 173, 180, 185 and the like. Preferably, C.I. I. Pigment Yellow 17, 74, 93, 97, 110, 155, and 180, and more preferably C.I. I. Pigment Yellow 74, 93, 97, 180, and C.I. I. Pigment Yellow 93, 97, 180 is preferable.
[0077]
Further, examples of red organic pigments include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17, 18, 22, 23, 31, 37, 38, 41, 42, 48: 1 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 54, 57: 1, 58: 4, 60: 1 63: 1, 63: 2, 64: 1, 65, 66, 67, 68, 81, 83, 88, 90, 90: 1, 112, 114, 115, 122, 123, 133, 144, 146, 147, 149,150,151,166,168,170,171,172,174,175,176,177,178,179,185,187,188,189,190,193,194,202,208,209,214, 216, 220, 221, 224, 2 2,243,243: 1,245,246,247, and the like. Preferably, C.I. I. Pigment Red 48: 1, 48: 2, 48: 3, 48: 4, 53: 1, 57: 1, 122 and 209, most preferably C.I. I. Pigment Red 57: 1, 122 and 209.
[0078]
When the organic pigments mentioned as the preferred organic pigments are used in the production method of the present invention, a toner having a higher sphericity and a sharp particle size distribution can be produced.
[0079]
The content of these organic pigments is preferably 1 to 20% by mass with respect to the total amount of toner particles. Especially, it is more preferable that it is 2-15 mass%, and it is especially preferable that it is 2-10 mass%. These organic pigments can be used alone or in combination of two or more.
[0080]
The dried toner particles can be used as a developer as they are, but it is preferable to add known external additives such as inorganic oxide fine particles and organic polymer fine particles to the toner particle surfaces as external additives for toner. . Hydrophobic silica, inorganic fine particles such as titanium oxide, or organic fine particles are externally added to toner particles to improve physical properties such as fluidity and chargeability when used as a dry developer by electrostatic printing. effective. As the type of external additive, hydrophobic silica treated with various silicone oils is preferably used. Examples thereof include hydrophobic silica treated with dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil, and olefin-modified silicone oil. The external addition method is processed using a known and commonly used method.
[0081]
By mixing a carrier with the toner particles, an electrostatic charge image developer can be obtained. The electrostatic charge image developer comprises a toner produced by the production method of the present invention and a magnetic carrier, preferably a magnetic carrier whose surface is coated with a resin.
[0082]
Iron powder, magnetite, ferrite, etc. used in the usual two-component development system can be used as the carrier core agent (magnetic carrier) used in the electrostatic image developer, but the true specific gravity is low, the resistance is high, and the environment Ferrite or magnetite that is excellent in stability and easy to be spherical and has good fluidity is preferably used. The shape of the core agent can be used without any problem, such as a spherical shape or an indefinite shape. The average particle size is generally 10 to 200 μm, but 30 to 110 μm is preferable for printing a high resolution image.
[0083]
Examples of coating resins for coating these core agents include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether polyvinyl ketone, vinyl chloride / vinyl acetate. Copolymers, styrene / acrylic copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluorine resins, (meth) acrylic resins, polyesters, polyurethanes, polycarbonates, phenol resins, amino resins, melamine resins, benzoguanamine resins Urea resin, amide resin, epoxy resin and the like can be used.
[0084]
Among these, silicone resins and (meth) acrylic resins are particularly excellent in charge stability and coating strength, and can be used more suitably. Further, the charging characteristics of a developer composed of toner particles and a carrier can be adjusted by adjusting the coating amount of a coating agent such as a silicone resin, adding a charge control agent, or adding a conductive material typified by carbon. That is, the resin-coated carrier used in the present invention is a resin-coated magnetic carrier coated with one or more resins selected from silicon resin and (meth) acrylic resin using ferrite or magnetite as a core agent. It is preferable to adjust the charging characteristics by adding a charge control agent, carbon or the like to the coating agent.
[0085]
Further, the toner produced by the production method of the present invention can be used in a normal non-magnetic one-component developing type printing apparatus, a two-component developing type printing apparatus, a magnetic one-component developing type printing apparatus, or the like. Further, on a flexible printed circuit board having an electrode having a function of adjusting the amount of toner passing through a powder toner that has been frictionally charged using a non-magnetic one-component developing device having a developer carrying roll and a layer regulating member. Therefore, it can be suitably used for a so-called toner jet type printer in which an image is formed by spraying directly on the paper on the back electrode through the hole. The toner produced by the production method of the present invention forms an electrostatic image on the latent image carrier, and develops the obtained electrostatic image using a developer carried on the developer carrier, Printing can be performed by an image forming method in which the toner image formed on the latent image holding member is transferred onto a transfer material such as paper or film, and the toner image on the transfer material is thermally fixed by a heat roll.
[0086]
【Example】
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In Examples and Comparative Examples, unless otherwise indicated, “part” means “mass part” and “water” means deionized water.
[0087]
(Example of polyester resin synthesis)
Trimellitic anhydride (TMA) as the polyvalent carboxylic acid, terephthalic acid (TPA), isophthalic acid (IPA) as the divalent carboxylic acid, and polyoxypropylene (2.4) -2,2-bis (4 as the aromatic diol -Hydroxyphenyl) propane (BPA-PO), polyoxyethylene (2.4) -2,2-bis (4-hydroxyphenyl) propane (BPA-EO), ethylene glycol (EG) as an aliphatic diol, 1 is used at a molar composition ratio shown in FIG. 1, and tetrabutyl titanate as a polymerization catalyst is charged into a separable fresco at 0.3% by weight with respect to the total amount of monomers. In a mounting electric heating mantle heater, after reacting at 220 ° C. for 15 hours under a normal pressure nitrogen stream, the pressure was reduced in order. The reaction was continued at mHg. The reaction was followed by a softening point according to ASTM E28-517. When the softening point reached a predetermined temperature, the vacuum was stopped and the reaction was terminated. Table 1 shows the composition and physical property values (characteristic values) of the synthesized resin.
[0088]
[Table 1]

[0089]
In Table 1, each abbreviation shows the following.
TMA: trimellitic anhydride
TPA; terephthalic acid
IPA; isophthalic acid
BPA-PO; polyoxypropylene (2.4) -2,2-bis (4-hydroxyphenyl) propane
BPA-EO; polyoxyethylene (2.4) -2,2-bis (4-hydroxyphenyl) propane
EG; ethylene glycol
FT value; Flow tester value
[0090]
The FT value is measured using a flow tester CFT-500 manufactured by Shimadzu Corporation, which is a constant load extrusion type capillary rheometer. The measurement condition with a flow tester is a piston cross-sectional area of 1 cm. ² Cylinder pressure was 0.98 MPa, die length was 1 mm, die hole diameter was 1 mm, measurement start temperature was 50 ° C., temperature increase rate was 6 ° C./min, and sample weight was 1.5 g.
Tfb, T1 / 2, and Tend in Table 1 are graphs showing the relationship between the temperature rise temperature T in the flow test by the flow tester and the stroke S of the piston. The temperature when the curve rises is Tfb, the temperature when the resin has almost completely flowed out and the curve is bent is Tend, and the stroke between Tfb and the stroke at Tend is an intermediate stroke. Is set to T1 / 2.
The glass transition temperature “Tg” (° C.) is an onset value measured at a rate of temperature increase of 10 ° C. per minute by the second run method using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation. .
[0091]
(Example of preparation of colorant master solution)
A carbon black pigment and a polyester resin (R1 in Table 1) are added to an organic solvent (methyl ethyl ketone) at a weight ratio of 40/60, pre-dispersed in a desper, and then motor mill M-1000 (US Eiger Corporation). The carbon black pigment master solution P1 was prepared by wet dispersion. Table 2 shows the properties of the master solution. As the carbon black pigment, carbon black “Elftex-8” manufactured by Cabot Corporation was used.
[0092]
[Table 2]

[0093]
(Preparation Example 1 of Release Agent Predispersion)
Carnauba wax "Carnauba Wax No. 1" (Yoko Kato imported product) 30 parts and 70 parts of polyester resin (Synthesis example R1 in Table 1) were kneaded with a pressure kneader to obtain a fine dispersion W-1 of a release agent. It was.
[0094]
(Preparation Example 2 of Release Agent Preliminary Dispersion)
After pre-dispersing 50 parts of Fischer-Tropsch wax “FT-100” (manufactured by Nippon Seiwa Co., Ltd.), 50 parts of polyester resin (Synthesis Example R1 in Table 1) and 150 parts of methyl ethyl ketone with Desper, Pearl Mill STS-1 type (Ashizawa) -Dispersion | distribution was carried out by Finetech Co., Ltd., solid content was adjusted to 35 weight%, and the fine dispersion W-2 of the mold release agent was obtained.
[0095]
(Example 1)
(Preparation process of release agent stable fine dispersion solution)
16.7 parts of the above release agent dispersion W-1, 15.0 parts of R1 resin and 38.7 parts of methyl ethyl ketone were weighed and pre-dispersed with Desper, and then the high-pressure homogenizer “HV-OH-07-3”. .7SS type "(manufactured by Izumi Food Machinery Co., Ltd.) was used for one-pass processing. The processing pressure at this time was 60 MPa. When the obtained dispersion was observed with a 400-fold optical microscope, the primary particles of the release agent were all 2 μm or less.
(Millbase preparation process)
The obtained release agent stable finely dispersed solution was transferred as a stirring blade to a cylindrical separable flask having a Max blend blade, and further 25 parts of the colorant master solution P1, 19.8 parts of R1 resin, and R2 resin. And 30.6 parts of methyl ethyl ketone were added and dissolved and dispersed for 3 hours while maintaining the temperature at 30 to 35 ° C. to obtain a mill base. When the obtained mill base was observed with a 400 × optical microscope, it was observed that the fine particles of the release agent were uniformly dispersed.
[0096]
(Phase inversion emulsification process)
Charge 545.5 parts of the mill base to a cylindrical separable flask having a Max blend blade, then add 47.8 parts of 1N ammonia water (equivalent to 1.2% carboxylic acid) and adjust to 210 rpm by a three-one motor. After fully stirring, 133 parts of deionized water was added and further stirred to adjust the temperature to 23 ° C. Subsequently, 133 parts of deionized water was added dropwise under the same conditions to prepare a fine particle dispersion by phase inversion emulsification. The peripheral speed of the stirring blade at this time was 0.71 m / s. Next, 279 parts of deionized water was added (the amount of deionized water in such an amount that the total amount of 1N ammonia water and water was 593 parts) to adjust the amount of solvent.
(Joint process)
Subsequently, 2.8 parts of Emar 0 (manufactured by Kao Corporation) which is an anionic emulsifier was diluted with 30 parts of water and added. Thereafter, the temperature is adjusted to 25 ° C. and the rotation speed is adjusted to 158 rpm, and an aqueous solution of 5.2% ammonium sulfate is dropped until the particle size grows to 5.5 μm. Thereafter, the particle size is adjusted to 7 μm under the same conditions. Stirring was continued until growth and the coalescence operation was completed. At this time, the amount of ammonium sulfate added was 300 parts. The peripheral speed of the stirring blade was 0.54 m / s. When the obtained particles were observed with an optical microscope of 400 times, all were uniform particles and the particle size distribution was good.
Thereafter, a part of the organic solvent and water was distilled off under reduced pressure, solid-liquid separation, washing, and drying were performed to obtain toner particles.
[0097]
(Example 2)
(Preparation process of release agent stable fine dispersion solution)
28.6 parts of the release agent dispersion W-2, 15.0 parts of R1 resin and 12.0 parts of methyl ethyl ketone were weighed and predispersed with a desper, and then the high-pressure homogenizer “HV-OH-07-3”. .7SS type "(manufactured by Izumi Food Machinery Co., Ltd.) was used for one-pass processing. The processing pressure at this time was 60 MPa. When the obtained dispersion was observed with a 400-fold optical microscope, the primary particles of the release agent were all 1 μm or less.
(Millbase preparation process)
The obtained release agent stable finely dispersed solution was transferred to a cylindrical separable flask having a Max blend blade as a stirring blade, and further 25 parts of the colorant master solution P1, 26.5 parts of R1 resin, and R2 resin. And 38.7 parts of methyl ethyl ketone were added and dissolved and dispersed for 3 hours while maintaining the temperature at 30 to 35 ° C. to obtain a mill base. When the obtained mill base was observed with a 400 × optical microscope, it was observed that the fine particles of the release agent were uniformly dispersed.
[0098]
(Phase inversion emulsification process)
Charge 545.5 parts of the mill base to a cylindrical separable flask having a Max blend blade, then add 47.8 parts of 1N ammonia water (equivalent to 1.2% carboxylic acid) and adjust to 210 rpm by a three-one motor. After fully stirring, 133 parts of deionized water was added and further stirred to adjust the temperature to 23 ° C. Subsequently, 133 parts of deionized water was added dropwise under the same conditions to prepare a fine particle dispersion by phase inversion emulsification. The peripheral speed of the stirring blade at this time was 0.71 m / s. Next, 279 parts of deionized water was added (the amount of deionized water in such an amount that the total amount of 1N ammonia water and water was 593 parts) to adjust the amount of solvent.
(Joint process)
Subsequently, 2.8 parts of Emar 0 (manufactured by Kao Corporation) which is an anionic emulsifier was diluted with 30 parts of water and added. Thereafter, the temperature is adjusted to 25 ° C. and the rotation speed is adjusted to 158 rpm, and an aqueous solution of 5.2% ammonium sulfate is dropped until the particle size grows to 5.5 μm. Thereafter, the particle size is adjusted to 7 μm under the same conditions. Stirring was continued until growth and the coalescence operation was completed. At this time, the amount of ammonium sulfate added was 310 parts. The peripheral speed of the stirring blade was 0.54 m / s. When the obtained particles were observed with an optical microscope of 400 times, all were uniform particles and the particle size distribution was good.
Thereafter, a part of the organic solvent and water was distilled off under reduced pressure, solid-liquid separation, washing, and drying were performed to obtain toner particles.
[0099]
(Comparative Example 1)
(Process for preparing release agent dispersion)
28.6 parts of the release agent dispersion W-2, 15.0 parts of R1 resin, and 12.0 parts of methyl ethyl ketone were weighed and predispersed with a desper. When the obtained dispersion was observed with a 400-fold optical microscope, the primary particles of the release agent were all 1 μm or less.
(Millbase preparation process)
The obtained release agent dispersion solution was transferred to a cylindrical separable flask having a Max blend blade as a stirring blade, and further 25 parts of colorant master solution P1, 26.5 parts of R1 resin, and R2 resin. 36 parts and 38.7 parts of methyl ethyl ketone were added and dissolved and dispersed for 3 hours while maintaining the temperature at 30 to 35 ° C. to obtain a mill base. When the obtained mill base was observed with a 400 × optical microscope, it was observed that the fine particles of the release agent were uniformly dispersed.
[0100]
(Phase inversion emulsification process)
After charging 545.5 parts of the mill base, 47.8 parts of 1N aqueous ammonia (equivalent to 1.2% carboxylic acid) was added, and after thorough stirring at 210 rpm with a three-one motor, 133 parts of deionized water was added. In addition, stirring was further performed to adjust the temperature to 23 ° C. Subsequently, 133 parts of deionized water was added dropwise under the same conditions to prepare a fine particle dispersion by phase inversion emulsification. The peripheral speed of the stirring blade at this time was 0.71 m / s. Next, 279 parts of deionized water was added (the amount of deionized water in such an amount that the total amount of 1N ammonia water and water was 593 parts) to adjust the amount of solvent.
(Joint process)
Next, 2.8 parts of Emar 0 (manufactured by Kao Corporation), which is an anionic emulsifier, was diluted with 30 parts of water and added. Thereafter, the temperature is adjusted to 25 ° C. and the rotation speed is adjusted to 158 rpm, and an aqueous solution of 5.2% ammonium sulfate is dropped until the particle size grows to 5.5 μm. Thereafter, the particle size is adjusted to 7 μm under the same conditions. Stirring was continued until growth and the coalescence operation was completed. The amount of ammonium sulfate added at this time was 270 parts. The peripheral speed of the stirring blade was 0.54 m / s. When the obtained particles were observed with a 400 × optical microscope, coarse particles and fine particles coexisted, and the particle size distribution was broad. In addition, some of the coarse particles were observed in which aggregates of fine particles that were supposed to be release agent fine particles were exposed.
Thereafter, a part of the organic solvent and water was distilled off under reduced pressure, solid-liquid separation, washing, and drying were performed to obtain toner particles.
[0101]
(Comparative Example 2)
(Process for preparing release agent dispersion)
16.7 parts of the release agent dispersion W-1, 15.0 parts of R1 resin and 38.7 parts of methyl ethyl ketone were weighed and pre-dispersed with Desper, and then Eiger Motor Mill “M-1000” (USA) 1 pass processing was performed using Eiger Corporation. When the obtained dispersion was observed with a 400-fold optical microscope, the primary particles of the release agent were all 1 μm or less.
(Millbase preparation process)
The obtained release agent dispersion solution was transferred to a cylindrical separable flask having a Max blend blade as a stirring blade, and further 25 parts of the colorant master solution P1, 19.8 parts of R1 resin, and 36 parts of R2 resin. 30.6 parts of methyl ethyl ketone was added and dissolved and dispersed for 3 hours while maintaining the temperature at 30 to 35 ° C. to obtain a mill base. When the obtained mill base was observed with a 400 × optical microscope, it was observed that the fine particles of the release agent were uniformly dispersed.
[0102]
(Phase inversion emulsification process)
Charge 545.5 parts of the mill base to a cylindrical separable flask having a Max blend blade, then add 47.8 parts of 1N ammonia water (equivalent to 1.2% carboxylic acid) and adjust to 210 rpm by a three-one motor. After fully stirring, 133 parts of deionized water was added and further stirred to adjust the temperature to 23 ° C. Subsequently, 133 parts of deionized water was added dropwise under the same conditions to prepare a fine particle dispersion by phase inversion emulsification. The peripheral speed of the stirring blade at this time was 0.71 m / s. Next, 279 parts of deionized water was added (the amount of deionized water in such an amount that the total amount of 1N ammonia water and water was 593 parts) to adjust the amount of solvent.
(Joint process)
Subsequently, 2.8 parts of Emar 0 (manufactured by Kao Corporation) which is an anionic emulsifier was diluted with 30 parts of water and added. Thereafter, the temperature is adjusted to 25 ° C. and the rotation speed is adjusted to 158 rpm, and an aqueous solution of 5.2% ammonium sulfate is dropped until the particle size grows to 5.5 μm. Thereafter, the particle size is adjusted to 7 μm under the same conditions. Stirring was continued until growth and the coalescence operation was completed. The amount of ammonium sulfate added at this time was 250 parts. The peripheral speed of the stirring blade was 0.54 m / s. When the obtained particles were observed with a 400 × optical microscope, coarse particles and fine particles coexisted, and the particle size distribution was broad. In addition, some of the coarse particles were observed in which aggregates of fine particles that were supposed to be release agent fine particles were exposed.
Thereafter, a part of the organic solvent and water was distilled off under reduced pressure, solid-liquid separation, washing, and drying were performed to obtain toner particles.
[0103]
Table 3 shows the evaluation results of the toners of Examples and Comparative Examples obtained as described above.
Evaluation of the particle size distribution of the toner and the like was performed by a multisizer TAII type (aperture tube diameter: 100 μm) manufactured by Coulter. In addition, 0.1 g of a surfactant (ELCLEAR (manufactured by Chugai Photo Chemical Co., Ltd.)) is added to 20 g of water, and 0.04 g of the sample toner is further added to the sample. Measurements were made after the particles were suspended in water.
[0104]
[Table 3]

[0105]
From the results of Examples and Comparative Examples, the release agent fine particles are uniformly dispersed in the system up to the mill base production process, but in the process of forming toner particles in the phase inversion emulsification process and the coalescence process, the high-pressure homogenizer It can be seen that the properties of the toner obtained are greatly affected by whether or not the process is performed. This is because the dispersion stability of the release agent particles is affected when the medium changes from an organic phase to an aqueous phase due to phase inversion emulsification. To maintain this stability, treatment with a high-pressure homogenizer is effective. It can be seen that it is.
[0106]
【The invention's effect】
As described above, according to the method for producing a toner for developing an electrostatic charge image of the present invention, a release agent such as wax is formed into fine particles and uniformly dispersed inside, and toner particles that are hardly exposed on the surface are produced. it can. Further, the obtained toner particles have a sharp particle size distribution.

Claims (5)

A release resin and a binder resin having a carboxyl group are pre-dispersed in an organic solvent to prepare a pre-fine dispersion, and this pre-fine dispersion is treated with a high-pressure homogenizer to form a release agent stable fine dispersion.
A binder resin having a carboxyl group and an organic pigment are added to this release agent stable fine dispersion and dissolved or dispersed to form a colored resin solution.
A basic compound is added to the colored resin solution to emulsify the colored resin solution in an aqueous medium, and fine particles of the colored resin solution are formed in the aqueous medium.
Next, a dispersion stabilizer and an electrolyte are sequentially added to form a unity of the fine particles, and after removing the organic solvent in the unity, the unity is separated from the aqueous medium and dried. A method for producing a toner for developing an electrostatic charge image. A release resin and a binder resin having a carboxyl group are pre-dispersed in an organic solvent to prepare a pre-fine dispersion, and this pre-fine dispersion is treated with a high-pressure homogenizer to form a release agent stable fine dispersion.
A binder resin having a carboxyl group and an organic pigment are added to this release agent stable fine dispersion and dissolved or dispersed to form a colored resin solution.
A basic compound is added to the colored resin solution to emulsify the colored resin solution in an aqueous medium, and fine particles of the colored resin solution are formed in the aqueous medium.
Next, after removing the organic solvent in the fine particles, an aggregate of the fine particles is formed by adding an electrolyte, and then the aggregate is heated and fused to form an aggregate. A method for producing a toner for developing an electrostatic image, wherein the toner is separated from an aqueous medium and dried. 3. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the binder resin is a polyester resin. 3. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the binder resin in the release agent stable fine dispersion also functions as a dispersion stabilizer for the release agent fine particles. The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 4, wherein the acid value of the binder resin is 3 to 20.