JP3867893B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

＞６０万；分子量６０万以上の成分の面積比率
＜１万 ；分子量１万以下の成分の面積比率
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
ＢＡ：安息香酸
ＴＭＰ；トリメチロールプロパン
ＦＴ値；フローテスター値
【０１０６】
表１において「Ｔ１／２温度」は、前述したように島津製作所製フローテスタ（ＣＦＴ−５００）を用いて、ノズル径１．０ｍｍΦ×１．０ｍｍ、単位面積（ｃｍ² ）当たりの荷重１０ｋｇ、毎分６℃の昇温速度で測定した値である。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値である。
【０１０７】
（離型剤分散液の調製例）
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）５０部とポリエステル樹脂（表１中Ｒ１）５０部とを加圧ニーダーで混練後、該混練物とメチルエチルケトン１８５部とをボールミルに仕込み、６時間攪拌した後取り出し、固形分含有量を２０重量％に調整し、離型剤の微分散液（Ｗ１）を得た。同様の方法でポリエステル樹脂Ｒ２を用いて離型剤の分散液（Ｗ２）を得た。
【０１０８】
（着色剤マスターチップの調製、及び着色剤分散液の調製例）
表２の配合にてカーボンブラックとカラー顔料を樹脂と５０／５０の重量比率で混練し着色剤マスターチップＰ１〜Ｐ５を作製した。カーボンブラックと樹脂は加圧ニーダーを用いて混練した。また、カラー顔料と樹脂は二本ロールで混練した。得られた混練物Ｐ２〜Ｐ４は固形分含有量が４０重量％となるようにメチルエチルケトンとともにボールミル中に仕込み、３６時間攪拌した後取り出し、固形分含有量を２０重量％に調整し、Ｐ２〜Ｐ４の着色剤分散液とした。
【０１０９】
【表２】

表２に示した着色剤は以下の通りである。
カーボン：「ＥＬＦＴＥＸ−８」（キャボット社製）
シアン顔料：ファーストゲンブルー ＴＧＲ（大日本インキ化学工業社製）
イエロー顔料：シムラーファーストイエロー ８ＧＲ（大日本インキ化学工業社製）
マゼンタ顔料：ファーストゲンスーパーマゼンタ Ｒ（大日本インキ化学工業社製）
【０１１０】
（湿式混練ミルベースの調製）
上記離型剤分散液、着色剤分散液、希釈樹脂（追加樹脂）、メチルエチルケトンをデスパーで混合し、固形分含有量を５５％に調整してミルベース（ＭＢ１〜ＭＢ５）を作製した。作製したミルベースの配合を表３に示す。
【０１１１】
【表３】

＞６０万；分子量６０万以上の成分の面積比率
＜１万 ；分子量１万以下の成分の面積比率
【０１１２】
表３で使用したブレンド樹脂の特性を表４に示した。樹脂のブレンドは２００メッシュを通過した樹脂粒子を上記重量比でブレンドして各物性値を測定した。
【０１１３】
【表４】

【０１１４】
（実施例１）
攪拌翼としてマックスブレンド翼を有する円筒型の２ＬセパラブルフラスコにミルベースMB1を５４５．５部、１規定アンモニア水２３．８部を加えて、スリーワンモーターにより３５０ｒｐｍ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３０℃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１．１９ｍ／ｓであった。次に、脱イオン水３３３部を加えて溶剤量を調整した。
【０１１５】
次いで、ノニオン型乳化剤であるエパン４５０(第一工業製薬社製)の４．１部を水に希釈して添加した後、温度を３０℃に、また回転数を２５０ｒｐｍに調整し、３％の硫酸アンモニュウムの水溶液４１０部を滴下して、分散液中の溶剤量を１５．５重量％とした。その後、同条件で５分間攪拌を続け合一操作を終了した。この時の攪拌翼の周速は０．８５ｍ／ｓであった。得られたスラリーは、遠心分離機で固液分離、洗浄を行い、その後、真空乾燥機で乾燥を行い、トナー粒子を得た。得られたトナー粒子の特性を表５、６に示す。
【０１１６】
（実施例２）
実施例１における５分間の合一操作を７０分間とする以外は実施例１と同様にしてトナー粒子を製造した。得られたトナー粒子の特性を表５、６に示す。
【０１１７】
（実施例３）
ノニオン型乳化剤を水に希釈して添加した後の攪拌装置を「Ｔ．Ｋ．ロボミクス」（特殊機化工業製ホモミクサー）に変更し、回転数を８０００ｒｐｍに調整して、合一操作を２０分間とする以外は実施例１と同様にしてトナー粒子を製造した。この時の攪拌翼の周速は１２．５６ｍ／ｓであった。得られたトナー粒子の特性を表５、６に示す。
【０１１８】
（実施例４）
実施例２におけるMB1をMB2とする以外は、実施例２と同様にしてトナー粒子を製造した。得られたトナー粒子の特性を表５、６に示す。
【０１１９】
（実施例５）
実施例２におけるMB1をMB3とする以外は、実施例２と同様にしてトナー粒子を製造した。得られたトナー粒子の特性を表５、６に示す。
【０１２０】
（実施例６）
実施例２におけるMB1をMB4とする以外は、実施例２と同様にしてトナー粒子を製造した。得られたトナー粒子の特性を表５、６に示す。
【０１２１】
（実施例７）
実施例２におけるMB1をMB5とする以外は、実施例２と同様にしてトナー粒子を製造した。得られたトナー粒子の特性を表５、６に示す。
【０１２２】
（実施例８）
実施例２におけるMB1をMB6とする以外は、実施例２と同様にしてトナー粒子を製造した。得られたトナー粒子の特性を表５、６に示す。
【０１２３】
（比較例１）
攪拌翼としてマックスブレンド翼を有する円筒型の２ＬセパラブルフラスコにミルベースMB1を５４５．５部、１規定アンモニア水２３．８部を加えて、スリーワンモーターにより３５０ｒｐｍ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３０℃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１．１９ｍ／ｓであった。次に、脱イオン水５００部を加えて溶剤量を調整した。
【０１２４】
次いで、乳化剤（分散安定剤）を添加せずに、温度を３０℃に、また回転数を２５０ｒｐｍに調整し、３％の硫酸アンモニュウム水溶液４１０部を滴下して溶剤量を１５．５重量％としたところ、滴下途中で微粒子全体が凝集し、粒子を取り出すことはできなかった。
【０１２５】
（比較例２）
実施例３において用いたノニオン型乳化剤及び硫酸アンモニュウムの水溶液を用いない以外は、実施例３と同様にしてトナー粒子を得た。得られたトナー粒子の特性を表５、６に示す。
【０１２６】
（比較例３）
攪拌翼としてマックスブレンド翼を有する円筒型の２ＬセパラブルフラスコにミルベースMB1を５４５．５部、１規定アンモニア水２３．８部を加えて、スリーワンモーターにより３５０ｒｐｍ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３０℃に調整した。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１．１９ｍ／ｓであった。次に、脱イオン水２００部を加えた後、固形分含有量が４０％となるまで、減圧下に有機溶剤を除去した。この時の溶剤量は１％以下となっていた。次いで、この分散液を希釈して固形分含有量を１５％に調整した。
【０１２７】
同様の攪拌装置及びフラスコに上記分散液１０００部を仕込み、温度を３０℃に、回転数を２５０ｒｐｍに調整した後、ノニオン型乳化剤であるＮＬ−２５０(第一工業製薬社製)０．７５部を水に希釈して添加し、その後１０％の硫酸アンモニュウム水溶液を１５０部添加した。
【０１２８】
この時点で、凝集した微粒子をサンプリングして顕微鏡で観察したところ、球形あるいは略球形の微粒子同志がその表面で接触して凝集している様子が観察された。微粒子同志が融着して一体化している様子は見られなかった。また、サンプリングした凝集粒子を水で洗浄すると個々の微粒子がバラバラになり凝集体がほぐれる様子が観察された。したがって、この時点における微粒子の凝集体は微粒子の会合体であって、本発明の製造方法における合一による凝集体ではないことが判る。
【０１２９】
その後、温度を１０℃／ｍｉｎで昇温し、８０で２時間攪拌をした後、ＮＬ−２５０(第一工業製薬社製)１．５部を水に希釈して添加しさらに温度を９０℃に上げて７時間攪拌を続け、凝集・融着操作を終了した。この時の攪拌翼の周速は０．８５ｍ／ｓであった。得られたスラリーは、遠心分離機で固液分離、洗浄を行い、その後、真空乾燥機で乾燥を行い、トナー粒子を得た。このように本比較例のトナー粒子は高温での長時間処理を行うことにより製造したトナー粒子である。得られたトナー粒子の特性を表５、６に示す。
【０１３０】
【表５】

【０１３１】
【表６】

【０１３２】
表６の粒径・粒度分布は、コールターベックマン社のコールターマルチサイザーＩＩの１００ミクロンアパーチャーチューブを用いて測定した。Dv50は５０％体積平均径であり、Dv50/Dn50は体積、及び個数の５０％平均径の比である。また、GSDは、８４％体積平均径を１６％体積平均径で割った値の平方根である。円形度分布は、東亜医用電子（株）製フロー式粒子像分析装置ＦＰＩＰ―１０００を用いて測定した。また、収率は、得られたトナー粒子の分散液を脱溶剤した後、５３０メッシュのふるいに通し、下記式で求めた値で、９０−１００％のものを○、８０−９０％のものを△、６０％以下を×とした。
【０１３３】
収率（％）＝｛（仕込んだミルベースの固形分量）−（ふるい上残さの固形分量）｝×１００ ／ （仕込んだミルベースの固形分量）
【０１３４】
【表７】

【０１３５】
ヘンシェルミキサーを用いて、各実施例及び各比較例のトナー粒子１００部に疎水性シリカ（クラリアント（株）社製Ｈ−２０１８）０．５部と酸化チタン（テイカ（株）社製ＪＭＴ−１５０ＡＯ）０．５部とを外添し、静電荷像現像用トナー（以下、粉体トナーと記す）を得た。得られた粉体トナーの熱特性、画像特性について、下記の評価方法により評価し、測定結果を表７に示した。
【０１３６】
定着温度幅については、以下に示す定着性試験によって定着温度を求めその上限値と下限値との範囲によって示した。
【０１３７】
（定着性試験）
各実施例および各比較例で製造されたトナー粒子を用いた各粉体トナーを用い、市販の非磁性二成分現像方式による複写機で未定着のテストパターンを現像した。この印刷紙を９０ｍｍ／秒のスピードで、リコーイマジオＤＡ−２５０のヒートロール（上部ヒートロール表面をテトラフルオロエチレンパーフルオロアルキルビニルエーテル共重合体で被覆したものを用いた）に通して定着を行い、定着後の画像にセロテープを貼り、剥離後のＩＤ（画像濃度）が元のＩＤの９０％以上であって、かつオフセットの発生が見られないときのヒートロールの表面温度を「定着温度」とした。表７に示した結果より、本発明の実施例のものは、オイル塗布を行わないオイルレス定着条件下で、定着開始温度、耐ホットオフセット温度ともに良好であることが確認された。
【０１３８】
（画出し試験）
また、各粉体トナーについて、市販の非磁性二成分現像方式による複写機及び非磁性一成分プリンターを用いて画出しを行った。得られた画像のかぶり、階調性、解像性について評価を行い、良好なものを○、やや劣るものを△、劣るものを×として示した。
【０１３９】
（ＯＨＰ鮮明度（カラー透明性）の評価方法）
ＯＨＰシート上に実施例４〜実施例６のトナー粒子を用いたカラートナーによる未定着画像を形成し、別に用意した定着試験器により未定着画像の定着を行った。ヒートロール温度１６０℃、９０ｍｍ／秒のスピードで、リコーイマジオＤＡ−２５０のヒートロール（オイルレス型：テトラフルオロエチレンパーフルオロアルキルビニルエーテル共重合体で被覆）に通して定着を行った。上記手順で作成したＯＨＰシート上に、クロで印刷されたＯＨＰシートを置き、オーバーヘッドプロジェクターにてスクリーンに投影し、文字の鮮明度を目視で評価した。評価結果は、鮮明に文字が見えるものを「○」、文字がぼやけるものを「△」、文字が判別できないものを「×」として表した。
【０１４０】
（耐熱保存性評価）
また、各粉体トナーについて、５０℃×３日間の耐熱ブロッキング性試験を行ったところ、全てのトナーにおいて凝集は見られなかった。
【０１４１】
各実施例では、短時間で球形の粒子を生産性良く製造できることがわかる。また、いずれの粒子も分布が非常にシャープであることがわかる。また、表７の結果を見ると、いずれもオイルレスの条件下で良好な定着性を示すことがわかる。実施例３は他の実施例に比べると微粒子、及び粗大粒子の発生が多く見られ、分布も若干広くなっている。これはステーターとローターの組み合わせによる高速分散機であるホモミクサー（特殊機化工業製）を用い、高剪断で合一を行ったためで、粒子の解砕による微粒子の発生、及び攪拌の不均一化による粗大粒子の発生が影響したものである。比較例１は乳化剤を用いないため、合一を制御できず、目的とするトナー粒子を得ることができなかった。また、比較例２は乳化剤、電解質を用いずに、高剪断力で合一を行ったものだが、微粒子の発生、粗大粒子の発生が多く、実施例のように、シャープな粒度分布の粒子を得ることはできないことがわかる。また、比較例３は凝集と融着工程の２段からなる粒子の製造方法であるが、融着し、球形化するには高温と多大な時間がかかり、生産性が本発明の実施例に比べ格段に劣ることがわかる。
【０１４２】
【発明の効果】
以上説明したように本発明の製造方法によれば、分散安定剤の存在下に、電解質を添加し、合一によりトナー粒子を得るため、乳化ロスがなく、高収率で、しかも粒度分布がシャープなポリエステル樹脂を結着樹脂とするトナー粒子を得ることができる。また、合一によりトナー粒子を得るため、球形あるいは略球形の粒子を加温することなく、短時間で製造可能な、生産性に優れた製造方法を提供するものである。
【図面の簡単な説明】
【図１】 フローテスタ値の求め方を説明するための図であり、（ａ）は測定装置の概要を示す側断面図、（ｂ）は測定値から各フローテスタ値を求める方法を説明するためのグラフである。[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 electrophotographic copying machines, printers, fax machines, and the like, and also used in toner jet printers.
[0002]
[Prior art]
In recent years, in electrophotographic copiers, printers, fax machines, etc., in order to further improve the quality of printed images, or to reduce the cost, size, power and resources of the machine, Such needs are increasing.
(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 powder toner by the pulverization method that has been used for a long time, as the particle size is reduced, (1) a colorant or wax exposed on the surface of the toner particles As the ratio of the release agent increases, charging control becomes difficult, (2) powder flowability deteriorates because the toner particles are indefinite, and (3) the energy cost required for production increases. Problems arise, and it is practically difficult to sufficiently satisfy the above-described needs with toner by a pulverization method.
[0004]
Against this background, development of toners (hereinafter referred to as chemical toners) by polymerization methods and emulsion dispersion methods has been actively conducted. Various methods are known for the toner by the polymerization method. Among them, a monomer, a polymerization initiator, a colorant, a charge control agent, and the like are added to an aqueous medium in the presence of a dispersion stabilizer while stirring. A suspension polymerization method is widely known in which droplets are formed and then heated to perform a polymerization reaction to obtain toner particles. Alternatively, an association method has been proposed in which toner particles are obtained by forming fine particles by emulsion polymerization or suspension polymerization, aggregating the fine particles, and further fusing the aggregated fine particles. However, the polymerization method or the association method using fine particles produced by the polymerization method has no problem in reducing the particle size of the toner particles, but the main component of the binder resin is limited to a vinyl polymer capable of radical polymerization. Therefore, it is not possible to produce a toner made of polyester resin or epoxy resin suitable for color toners. In addition, the polymerization method has a problem that it is difficult to reduce VOC (volatile organic compounds composed of unreacted monomers), and improvement thereof is desired.
[0005]
On the other hand, a toner production method using an emulsification dispersion method is performed by mixing a mixture of a binder resin and a colorant with an aqueous medium, as disclosed in JP-A-5-66600 and JP-A-8-21655. In this method, toner particles are obtained by emulsification. In addition to being able to easily cope with the reduction in the particle size and spheroidization of the toner as in the polymerization method, (1) the type of binder resin compared to the polymerization method (2) The residual monomer can be easily reduced, and (3) the concentration of the colorant and the like can be arbitrarily changed from a low concentration to a high concentration.
[0006]
By the way, a polyester resin is preferable to a styrene-acrylic resin as a binder resin for a toner, which has a relatively low fixing temperature and tends to melt sharply at the time of fixing and smooth the image surface. A polyester resin excellent in flexibility is preferred. However, as described above, the polymerization method cannot produce toner particles having a polyester resin as a main component of the binder resin. Therefore, in recent years, attention has been focused on producing a small particle size toner using a polyester resin as a binder resin by an emulsification dispersion method.
[0007]
However, in each of the above publications for producing toner by the above-described emulsification dispersion method, it is not always sufficient to lower the fixing temperature of the toner, widen the offset temperature range, etc. In the toner manufacturing method according to the method, since a mixed solvent is used, it is difficult to recover and reuse the solvent, and the generation of fine particles is unavoidable, and the loss of emulsification (water-soluble resin) also occurs, resulting in a decrease in toner yield. There was a problem that productivity was inferior.
[0008]
As a manufacturing method for solving such a problem, for example, in JP-A-10-020552, JP-A-11-007156, etc. (hereinafter referred to as A patent group), a polyester resin is used as a binder resin. After emulsification and dispersion, the resulting fine particles are agglomerated and further heated and fused to form an aggregate to form toner particles. According to such a production method, it is considered that there is no generation of ultrafine particles, and therefore there is no loss of emulsification, and it is possible to produce a classification-free toner having a sharp particle size distribution. It is necessary to stir for a long time, and there is a problem in productivity. Further, if it is desired to obtain irregularly shaped particles as in the pulverization method, obtaining spherical or substantially spherical particles requires a longer treatment at a high temperature, which also has a problem with productivity.
[0009]
In JP-A-10-147649, JP-A-10-319639, etc. (hereinafter referred to as B patent group), after the binder resin is emulsified and dispersed, fine particles are aggregated by a production method different from that of the A patent group. A method for forming toner particles and producing toner particles is proposed. That is, in the production method described in the A patent group, after the binder resin and the like are emulsified and dispersed in an aqueous medium, the obtained particles are aggregated, and then the aggregated particles are heated to be fused. In contrast to the method of producing toner particles in a two-stage production process, such as the step of causing the toner to be produced, the toner production method proposed in the above B patent group is a method of producing fine particles after producing fine particles by emulsion dispersion. In this method, toner particles are produced by simultaneously performing the step of aggregating the particles and the step of fusing the agglomerated fine particles together. Hereinafter, in the present invention, a toner production method in which the fine particles produced by emulsification dispersion are aggregated and fused in one step will be referred to as a “gathering” production method. A toner manufacturing method that sequentially performs the steps is described as a “meeting” manufacturing method to distinguish the two. According to the production method based on coalescence, spherical toner particles can be obtained easily and in a short time. However, in the production method according to the B patent group, (1) the dispersion is not performed using a dispersion stabilizer or an electrolyte, and the coalescence is performed by collision between particles under a high shearing force. The generation of aggregates is inevitable. (2) Since emulsification and dispersion is performed under a high shearing force, and then the particles are aggregated under the same conditions, crushing occurs at the same time as coalescence, so that the generation of fine particles increases, and the distribution of toner particles generated There was a limit to narrowing.
[0010]
Further, in the polyester resins specifically shown in these A patent group and B patent group, although the fixing performance at low temperature is improved, the offset resistance at high temperature is inferior. The oil-less heat roll fixing was inadequate.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and the object of the present invention is to produce a new chemical toner having a binder resin made of a polyester resin with no loss of emulsification, high yield and sharp particle size distribution. Is to provide a simple manufacturing method. Another object of the present invention is to provide a novel production method for producing a spherical or substantially spherical chemical toner in a simple and short time. Another object of the present invention is to produce a novel chemical toner suitable for a so-called oil-less fixing method having a good fixing / offset temperature range without using an offset prevention liquid as a toner used in a heat roll fixing method. It is to provide a method.
[0012]
[Means for Solving the Problems]
The inventors of the present invention focused on a method for producing a chemical toner by coalescence, and as a result of intensive research, they found a method for producing a toner for developing an electrostatic image capable of solving the above-mentioned problems, and completed the present invention. That is, the present invention forms fine particles of the mixture in the aqueous medium by emulsifying the mixture containing at least the polyester resin and the organic solvent in the aqueous medium.First step,
Next, a dispersion stabilizer is added, and an electrolyte is sequentially added to unite the fine particles.Second step of producing an aggregate of the fine particles,
Third step of removing the organic solvent contained in the aggregate, separating the aggregate of fine particles from the aqueous medium, washing, and then drying
TheSequentiallyIt is an object of the present invention to provide a method for producing a toner for developing an electrostatic charge image, which produces a toner by carrying out the process.
[0013]
In the production method of the present invention, coalescence can be stably performed by adding a dispersion stabilizer to a dispersion obtained by emulsifying a mixture containing a polyester resin and the like, and then adding an electrolyte. Furthermore, a chemical toner using a polyester resin as a binder resin with no emulsification loss and a sharp particle size distribution can be obtained easily, in a short time, and in a high yield. In particular, the above effect is remarkable by stirring under a low shear force using a manufacturing apparatus having a stirring blade whose tip rotates at a peripheral speed of 0.2 to 10 m / s, or 0.2 to 10 m / s. It becomes.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. The production method of the present invention comprises the following steps.
First step: a step of emulsifying a resin solution containing at least a polyester resin and an organic solvent in an aqueous medium to form fine particles,
Second step: combining the fine particles to produce an aggregate of the fine particles,
Third step: After removing the organic solvent contained in the agglomerates, separating the agglomerates of the fine particles from the aqueous medium, drying the agglomerates, and drying to produce a toner (the toner in the present invention is the first Refers to the dried aggregate produced in three steps)
The above three steps.
[0015]
In the first step, a polyester resin is introduced into an organic solvent, and the mixture containing the polyester resin and the organic solvent is prepared by dissolving and dispersing the resin (heating as necessary). In this case, one or more selected from various colorants, release agents or charge control agents, or other additives can be used together with the polyester resin as the toner raw material. In the present invention, it is preferable to disperse the colorant in the organic solvent together with the polyester resin, and it is particularly preferable to dissolve or disperse various additives such as a release agent and a charge control agent.
[0016]
As a means for dissolving or dispersing a polyester resin and various additives such as a colorant, a release agent, and a charge control agent in an organic solvent, the following method is preferably used.
[0017]
(1) Polyester resin to be used by using a mixture containing various additives such as the above-mentioned polyester resin, colorant, release agent, charge control agent, etc., using a pressure kneader, a heated two-roll, two-screw extrusion kneader, etc. Is kneaded by heating to a temperature not lower than the softening point and not higher than the thermal decomposition temperature. At this time, the colorant and 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.
Or
(2) A polyester resin and various additives such as a colorant, a release agent, and a charge control agent are mixed with an organic solvent, and this is wet-kneaded by a ball mill or the like. In this case, the colorant, the release agent, and the like may be mixed after preliminary dispersion separately in advance.
[0018]
More specific means of the above (2) includes a resin solution in which a polyester resin is dissolved in an organic solvent in advance 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 a colorant. A resin solution in which a coloring agent, a release agent, etc. are finely dispersed in an organic solvent by adding a polyester resin for dilution and an additional organic solvent. There is a method of manufacturing. At this time, rather than putting the colorant or the release agent untreated directly into a mixing / dispersing machine such as a ball mill, a low-viscosity polyester resin and a colorant, or a release agent, etc. in a pressure kneader, It is preferable to use a master batch obtained by kneading and dispersing with two heated rolls. The production method (2) as described above is preferable to the method (1) in which the polymer component (gel component) of the polyester resin is not cut and is dispersed by melt-kneading.
[0019]
Examples of the organic solvent for dissolving or dispersing the polyester resin and a colorant or a release agent added as necessary include hydrocarbons such as pentane, hexane, heptane, benzene, toluene, xylene, cyclohexane, and petroleum ether. 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, butyl acetate, etc. Used. 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 a solvent that dissolves the binder resin, has a relatively low toxicity, and has a low boiling point that is easy to remove the solvent in a subsequent process. As such a solvent, methyl ethyl ketone is most preferable.
[0020]
Next, as a method of emulsifying a mixture containing a polyester resin and an organic solvent in an aqueous medium, a mixture prepared by the above method comprising a polyester resin, a coloring agent added as necessary, and an organic solvent, It is preferable to mix and emulsify with an aqueous medium in the presence of a basic neutralizing agent. In this step, a method of gradually adding an aqueous medium (water or a liquid medium containing water as a main component) to a mixture composed of a polyester resin, a colorant, and the like and an organic solvent is preferable. In that case, by gradually adding water to the organic continuous phase of the mixture, a water-in-oil discontinuous phase is generated, and by adding additional water, the oil-in-water discontinuous phase is added. To form a suspension / emulsion in which the mixture is suspended as particles (droplets) in an aqueous medium (hereinafter, this method is referred to as phase inversion emulsification).
[0021]
In phase inversion emulsification, water is added so that the ratio of water to the total amount of the organic solvent and added water is 30 to 70%. More preferably, it is 35 to 65%, and particularly preferably 40 to 60%. The aqueous medium used is preferably water, more preferably deionized water.
[0022]
The polyester resin used in the present invention is preferably an acidic group-containing polyester resin, and is a polyester resin that becomes self-water-dispersible by neutralizing the acidic group (hereinafter referred to as self-water-dispersible resin). It is preferable. The acid value of the self-water dispersible polyester resin used in the present invention is preferably 1-20. The resin having self-water dispersibility becomes an anionic type by neutralizing an acidic group with a basic neutralizing agent. 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. Examples of the acidic group include an acidic group such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group. Among these, a carboxyl group is preferable from the viewpoint of toner charging characteristics. The basic substance for neutralization 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 polyester resin in the aqueous medium, there is a method of adding a dispersion stabilizer such as a suspension stabilizer or a surfactant. However, the suspension stabilizer or the surfactant is added and emulsified. The method requires high shear forces. As a result, the generation of coarse particles and the particle size distribution become broad, which is not preferable. Therefore, in the present invention, it is preferable to use a self-water dispersible resin and neutralize the acidic group of the resin with a basic compound.
[0023]
As a method for neutralizing the acidic group (carboxyl group) of the polyester resin with a base, for example, (1) after producing a mixture containing a polyester resin having an acidic group, a colorant, a wax and an organic solvent, Or (2) a method in which a basic neutralizing agent is mixed in advance in an aqueous medium, and the acid groups of the polyester resin contained in the mixture are neutralized when phase-inverted and emulsified.
[0024]
Examples of the phase inversion emulsification method include (A) a method in which the mixture is added to an aqueous medium to emulsify, or (B) a method in which the aqueous medium is added to the mixture. In the present invention, it is preferable to adopt a method in which the above (1) and (B) are combined so that the particle size distribution becomes sharp.
[0025]
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.
[0026]
However, rather than using the above-described disperser with a high share, for example, a stirring device, an anchor blade, a turbine blade, a fiddler blade, a full zone blade, a max blend blade, a meniscal blade as disclosed in JP-A-9-114135 Etc. are preferably used. 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 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 is not preferable because the higher the temperature, the more coarse particles are generated. On the other hand, when the temperature is too low, the viscosity of the mixture containing the polyester 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.
[0027]
As described above, by performing phase inversion emulsification under low share using self-water dispersible resin, generation of fine powder and coarse particles can be suppressed, and as a result, uniform particle size distribution in the next coalescence process It becomes easy to produce an aggregate of fine particles. In addition, when a polyester resin having no self-water dispersibility is used, or when phase inversion emulsification is performed under a high share, the generation of coarse particles or the low molecular weight component of the resin generates fine powder, and toner particles The particle size distribution of the toner is widened, and furthermore, particles containing low molecular weight components are removed by sieving performed in the subsequent process, which causes a problem that the low temperature fixing property of the toner is deteriorated. Such inconvenience does not occur by using a water dispersible resin or performing phase inversion emulsification under a low share.
[0028]
The 50% volume average particle diameter of the fine particles produced in the first 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, when a colorant or a release agent is used, it is not preferable because it is not sufficiently encapsulated by the polyester resin, which adversely affects charging characteristics and development characteristics. If the particle size is large, the particle size of the toner to be obtained is limited. Therefore, it is necessary to make the particle size smaller than the particle size of the target toner, but if it is larger than 6 μm, coarse particles are likely to be generated. Therefore, it is not preferable. The particle size distribution of the fine particles produced in the first step is such that the ratio of the volume particle diameter of 10 μm or more is 2% or less, more preferably 1% or less, and the ratio of the volume particle diameter of 5 μm or more is 10% or less. Preferably it is 6% or less.
[0029]
In the second step, the fine particles obtained in the first step are united to form an aggregate of the fine particles, thereby forming toner particles having a desired particle diameter. In the second step, desired aggregates can be obtained by appropriately controlling the amount of solvent, temperature, type or amount of dispersion stabilizer and electrolyte, stirring conditions and the like.
[0030]
A method for producing aggregates by producing fine particles by emulsion polymerization, and then aggregating the fine particles and then fusing at a high temperature is well known. The production method of the present invention is different from the aggregate produced through the two-stage process of aggregation / fusion as described above, and the production method for obtaining the aggregate in a single-stage process including the fusion process simultaneously with the aggregation. It is a (manufacturing method based on coalescence) and has a feature that spherical or substantially spherical particles can be obtained in a short time without heating.
[0031]
In the above-mentioned B patent group, a method is proposed in which toner particles are subsequently produced by coalescence after the binder resin is emulsified and dispersed under high shear. In this production method, the particle size of the aggregate is controlled by a balance between coalescence caused by collisions between particles and the rate at which the coalesced aggregate is dissociated and dispersed by high shear force under high shear. . Further, the method of adding the dispersion stabilizer and the electrolyte, and the timing are not disclosed, so it is impossible to sufficiently suppress the generation of fine particles and coarse particles in the coalescence process, sharpening the particle size distribution, There is a limit in improving the yield.
[0032]
In the second step of the present invention, the dispersion of fine particles obtained in the first 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.
[0033]
The fine particles formed from the self-water dispersible resin obtained up to the first step are stably dispersed in the aqueous medium by the action of the electric double layer by the carboxylate. In the second step of the present invention, the particles are destabilized by adding an electrolyte that destroys or reduces the electric double layer to the aqueous medium in which the fine particles are dispersed. Examples of the electrolyte that can be used in the present invention 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 to be added for unity may be used alone or in combination of two or more kinds. 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 first step are swollen by the solvent, and the electric double layer of the particles is in an unstable state due to 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.
[0034]
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 various nonionic emulsifiers such as pluronics, alkyl sulfate ester type anionic emulsifiers, and quaternary ammonium salt type cationic dispersion stabilizers. Among these, even if an anion type or nonionic type dispersion stabilizer is added in a small amount, 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. In the production method of the present invention, by adding an electrolyte in the presence of a dispersion stabilizer (emulsifier), it becomes possible to prevent non-uniform coalescence, and as a result, a sharp particle size distribution is obtained. An improvement in yield is achieved.
[0035]
Further, in order to promote uniform coalescence, the temporary stirring conditions are important. For example, an agitator, an anchor blade, a turbine blade, a fiddler blade, a full zone blade, a max blend blade, a cone cape blade, a helical blade, a double helical blade, a meniscal blade, etc. as disclosed in JP-A-9-114135 Used. Among these, a large wing excellent in uniform mixing properties such as a Max blend wing and a full zone wing is preferable. In the production method of the present invention, the fine particles swollen by the solvent are united and aggregated by collision by stirring. For this reason, a high shearing device consisting of a stator and a rotor such as a homomixer or a high shearing device such as a turbine blade that is locally subjected to high shearing and a stirring blade that has a weak ability to uniformly stir the whole result in non-uniform coalescence. It tends to lead to generation of particles. Therefore, as stirring conditions, it is preferable that a circumferential speed is 0.2-10 m / s, and less than 0.2-8 m / s is more preferable. Most preferably, it is 0.2-6 m / s. When the peripheral speed is faster than 10 m / s, non-uniform coalescence occurs and coarse particles are easily generated, which is not preferable. On the other hand, if it is slower than 0.2 m / s, the stirring share is insufficient, so that non-uniform coalescence tends to occur and coarse particles tend to be generated.
[0036]
In the production method of the present invention, unlike the inventions described in the above-mentioned B patent group, coalescence proceeds only by collision of fine particles, and the coalesced aggregate does not dissociate / disperse again. Therefore, the generation of ultrafine particles is small and the particle size distribution becomes sharp, so that the yield can be improved.
[0037]
In the second step of the present invention, it is preferable to further dilute the fine particle dispersion obtained by phase inversion emulsification in the first step with water as necessary. 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 after adding the electrolyte is preferably in the range of 5 to 25% by weight. Moreover, the inside of the range of 5-20 weight% is more preferable, and the inside of the range of 5-18 weight% is especially preferable. If the amount of solvent is less than 5% by weight, the electrolytic mass required for coalescence is increased, which is not preferable. On the other hand, when the amount of the solvent is more than 25% by weight, the generation of aggregates due to non-uniform coalescence increases, and the amount of dispersion stabilizer added increases, which is not preferable.
[0038]
In the present invention, the shape of the toner particles after coalescence can be controlled by adjusting the amount of the solvent. When the amount of the solvent is in the range of 13 to 25% by weight, 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 5 to 13% by weight, the degree of swelling of the fine particles by the solvent is small, so that irregular-shaped or substantially spherical toner particles can be easily obtained.
[0039]
The amount of the dispersion stabilizer used is preferably in the range of 0.5 to 3.0% by weight, for example, with respect to the solid content of the fine particles. A range of 0.5 to 2.5% by weight is more preferable, and a range of 1.0 to 2.5% by weight is particularly preferable. When the amount is less than 0.5% by weight, the desired effect of preventing the generation of coarse particles cannot be obtained. On the other hand, if the amount is more than 3.0% by weight, 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 yield. Is not preferable.
[0040]
Moreover, it is preferable that the quantity of the electrolyte to be used exists in the range of 0.5 to 15 weight% with respect to solid content of microparticles | fine-particles. The content is more preferably in the range of 1 to 12% by weight, and particularly preferably in the range of 1 to 10% by weight. If the amount of the electrolyte is less than 0.5% by weight, the coalescence does not proceed sufficiently, which is not preferable. On the other hand, when the amount of the electrolyte is more than 15% by weight, the coalescence becomes non-uniform, which is not preferable because the generation of aggregates or coarse particles is generated and the yield is lowered.
[0041]
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. When the temperature is lower than 10 ° C., it is difficult to perform coalescence, which is not preferable. On the other hand, when the temperature is higher than 50 ° C., the coalescence speed is increased, and aggregates and coarse particles are easily generated, which is not preferable. In the production method of the present invention, it is possible to produce aggregates by coalescence under low temperature conditions such as 20 to 40 ° C. Therefore, unlike the association method, it is not necessary to raise the temperature to 80 to 90 ° C. in order to fuse the fine particles after fusing.
[0042]
In the first step and the second step in the present invention, various embodiments can be employed without departing from the spirit of the present invention. Among these, preferred embodiments include the following (1) to (4).
(1) A method in which fine particles are produced by the above first step using a resin solution comprising a polyester resin and a colorant, and if necessary, a release agent and a charge control agent, and the second step (unification step) is performed.
(2) Using a resin solution comprising a polyester resin and a colorant, and if necessary, a release agent, fine particles are produced by the first step, and a dispersion of the charge control agent is mixed to obtain a second step ( Method to perform the unification process)
(3) Fine particles made of polyester resin are produced in the first step, and one or more of a colorant dispersion and, if necessary, a release agent and a charge control agent dispersion are prepared separately. And performing the second step (unification step) after mixing them
(4) Using a resin solution comprising a polyester resin and a release agent, fine particles are produced by the first step described above, and a dispersion of a colorant and, if necessary, a dispersion of a charge control agent are mixed. Method of performing two steps (joining step)
[0043]
Various dispersions such as a colorant dispersion, a charge control agent dispersion, and a release agent dispersion used here can be obtained as follows. For example, nonionic surfactants represented by polyoxyethylene alkylphenyl ethers, anionic surfactants represented by alkylbenzene sulfonates, alkyl sulfate esters, etc., or quaternary ammonium salts. It can be prepared by a mechanical pulverization method using a medium by adding it to water with a cationic surfactant represented by Alternatively, instead of the surfactant, a self-water dispersible polyester resin can be used to prepare a dispersion by the same dispersing means in the presence of a basic neutralizing agent. The colorant, release agent, and charge control agent used here may be those previously melt-kneaded with a polyester resin. In this case, when the resin is adsorbed, the degree to which various materials are exposed on the particle surface is alleviated, and preferable characteristics are provided in charging characteristics and development characteristics.
[0044]
By the way, in order to maintain the frictional charging performance satisfactorily, it is effective to prevent the colorant and the like from being exposed on the surface of the toner particles, that is, to have a toner structure in which the colorant and the like are included in the toner particles. The deterioration in chargeability associated with the reduction in toner particle size is caused by the fact that a part of the contained colorant and other additives (usually wax etc.) are exposed on the toner particle surface. That is, even when the content (% by weight) of the colorant and the like is the same, the surface area of the toner particle is increased by reducing the particle size, and the ratio of the colorant and wax exposed on the surface of the toner particle is increased. 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 desirably have a colorant, wax, or the like encapsulated in a binder resin, and a good printed image can be obtained by having such an encapsulated structure. In order to positively encapsulate the colorant or release agent, the above method (1) or (2) is preferred. Whether the colorant, wax or the like is not exposed on the toner particle surface can be easily determined by observing the cross section of the particle with a TEM (transmission electron microscope), for example. More specifically, the cross section obtained by embedding the toner particles with a resin and cutting with a microtome is dyed with ruthenium oxide or the like, if necessary, and is observed with a TEM. It can be confirmed that they are dispersed. In order to localize the charge control agent on the surface of the toner particle and to exhibit its function, the method (2) is preferable.
[0046]
The shape of the fine particle aggregate obtained in the second step can be changed from an indeterminate shape to a spherical shape depending on the degree of coalescence. 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 toner particles obtained by drying the aggregates of fine particles, and measuring and calculating them. Since it can be easily obtained by using a flow type particle image analyzer FPIP-1000 manufactured by Electronic Co., Ltd., the average circularity is a value measured by this apparatus in the present invention.
[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 dispersion of fine particle aggregates obtained in the second step is subsequently subjected to solvent removal to remove the organic solvent from the slurry (third step). Subsequently, dust and coarse particles such as resin pieces are removed by passing through a wet vibrating screen, and solid-liquid separation 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.
[0049]
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.
[0050]
Regarding the particle size distribution of the toner obtained by the production method of the present invention, the 50% volume particle size / 50% number particle size is preferably 1.25 or less, more preferably 1 as measured by a multisizer TAII type manufactured by Coulter. .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.
[0051]
The toner obtained by the production method of the present invention preferably has a volume average particle diameter in the range of 1 to 13 μm from the viewpoint of image quality to be obtained, and about 3 to 10 μm can be matched with the current machine. It is more preferable because it is easy. For color toners, a volume average particle size of about 3 to 8 μm is preferred. 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.
[0052]
The polyester resin used in the present invention is synthesized by dehydration condensation of a polybasic acid and a polyhydric alcohol.
[0053]
Examples of the polybasic acid include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and 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.
[0054]
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 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.
[0055]
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.
[0056]
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.
[0057]
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 to 1 weight% with respect to the total amount of a raw material.
[0058]
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.
[0059]
In order to have a good fixing / offset temperature range without using an anti-offset liquid as a toner used in the heat roll fixing method, the polyester resin is obtained by a constant load extrusion type capillary rheometer (hereinafter referred to as a flow tester). It is preferable to be in the following range in measurement. That is, the outflow start temperature Tfb by the flow tester is in the range of 80 ° C to 120 ° C, the T1 / 2 temperature is in the range of 120 ° C to 160 ° C, and the outflow end temperature Tend is in the range of 130 ° C to 210 ° C. By using the polyester resin having such a flow tester value, the toner for developing an electrostatic charge image of the present invention has a good oilless fixability. Moreover, it is preferable that a glass transition temperature (Tg) is 40-75 degreeC.
[0060]
In the present invention, the outflow start temperature Tfb, T1 / 2 temperature, and outflow end temperature Tend by the flow tester are obtained using a flow tester (CFT-500) manufactured by Shimadzu Corporation. As shown in FIG. 1A, this flow tester has a resin 2 (weight 1.5 g) on a cylinder 2 having a nozzle 1 having a nozzle diameter D of 1.0 mmΦ and a nozzle length (depth) L of 1.0 mm. ), And the unit area (cm²It is obtained by measuring the stroke S of the load surface 4 (sink value of the load surface 4) when heated at a rate of temperature increase of 6 ° C. per minute. That is, the relationship between the temperature rise and the stroke S is obtained as shown in FIG. 1B, and when the resin S 3 starts to flow out of the nozzle 1, the stroke S suddenly increases and the curve rises. The temperature is Tfb, and the temperature when the outflow of the resin 3 from the nozzle 1 is almost finished and the curve is bent is assumed to be Tend. The temperature at S1 / 2, which is an intermediate value between the stroke Sfb at Tfb and the stroke Send at Tend, is defined as T1 / 2 temperature.
[0061]
Measurement by the temperature rising method using this device is performed by testing while raising the temperature at a constant rate as the test time elapses, so that the sample reaches from the solid region to the transition region, the rubbery elastic region, and the fluidized region. The process can be measured continuously. With this apparatus, the shear rate and viscosity at each temperature in the flow region can be easily measured.
[0062]
The outflow start temperature Tfb is an index of the sharp melt property and low temperature fixability of the polyester resin. If the temperature is too high, the low temperature fixability is deteriorated and cold offset is likely to occur. On the other hand, when the temperature is too low, the storage stability is lowered, and hot offset tends to occur. Therefore, the outflow start temperature Tfb of the toner for developing an electrostatic charge image of the present invention is more preferably 90 ° C. to 115 ° C., and particularly preferably 90 to 110 ° C.
[0063]
Also, the toner melting temperature T1 / 2 and the outflow end temperature Tend by the 1/2 method are indicators of hot offset resistance. The particle size distribution deteriorates. Moreover, when all are too low temperature, it will become easy to generate | occur | produce offset and practicality will fall. Therefore, the melting temperature T1 / 2 by the 1/2 method needs to be 120 ° C to 160 ° C, more preferably 130 ° C to 160 ° C, and the outflow end temperature Tend is preferably 130 ° C to 210 ° C, 130 to 180 degreeC is more preferable. By setting Tfb, T1 / 2, and Tend within the above ranges, fixing can be performed in a wide temperature range.
[0064]
The polyester resin described above contains a crosslinked polyester resin, and the tetrahydrofuran-insoluble content of the binder resin is in the range of 0.1 to 20% by weight, more preferably in the range of 0.2 to 10% by weight. Preferably, the content is in the range of 0.2 to 6% by weight, and thus a good hot offset resistance is ensured by making the binder resin a polyester resin having a tetrahydrofuran insoluble content of 0.1 to 20% by weight. This is preferable. If it is less than 0.1% by weight, the effect of improving hot offset resistance is insufficient, which is not preferable. If it exceeds 20% by weight, the solution viscosity becomes too high, the fixing start temperature becomes high, and the fixing property is unbalanced. Moreover, since sharp melt property is impaired, transparency, color reproducibility, and gloss in color images are inferior, which is not preferable.
[0065]
Here, with respect to the above-mentioned tetrahydrofuran-insoluble content of the binder resin, 1 g of the resin was precisely weighed and added to 40 ml of tetrahydrofuran to completely dissolve it, and a funnel (diameter 40 mm) with Kiriyama filter paper (No. 3) placed thereon. 2g of radiolite (# 700, Showa Chemical Co., Ltd.) is spread uniformly on the top and filtered. The cake is placed on an aluminum petri dish, then dried at 140 ° C for 1 hour, and the dry weight is measured. Then, a value obtained by dividing the residual resin amount in the dry weight by the initial resin sample amount is calculated as a percentage, and this value is defined as the insoluble content.
[0066]
The binder resin preferably contains a highly viscous crosslinked polyester resin and a low viscosity branched or linear polyester resin. That is, in the polyester resin of the present invention, the binder resin may be composed of one type of polyester resin, but generally a cross-linked polyester resin (cross-linked polyester resin) having a high molecular weight and high viscosity, It is practical to blend with a branched or linear polyester resin that has a low viscosity in terms of molecular weight in order to obtain a good fixing start temperature and hot offset resistance. preferable. When blended and used, the flow tester value of the blended resin may be in the above numerical range. In the present invention, the crosslinked polyester resin indicates a resin having a component insoluble in tetrahydrofuran, and the branched or linear polyester resin indicates a resin that has no gel content and dissolves in tetrahydrofuran as measured by the gel content.
[0067]
In the present invention, a plurality of polyester resins having different melt viscosities can be used as the binder resin. For example, when a mixture of a low-viscosity branched or linear polyester resin and a high-viscosity cross-linked polyester resin is used, It is more preferable to use a mixture of a branched or linear polyester resin (A) and a crosslinked or branched polyester resin (B) under the conditions shown below. At this time, the melt viscosity and blending amount of the resin (A) and the resin (B) are appropriately adjusted so that the flow tester value of the blended resin falls within the above numerical range.
[0068]
That is, as the polyester resin (A), a T1 / 2 temperature measured by a flow tester is 80 ° C. or higher and lower than 120 ° C., and a glass transition temperature Tg is 40 ° C. to 70 ° C. As B), a T1 / 2 temperature measured by a flow tester is 120 ° C. or more and 210 ° C. or less, a crosslinked or branched polyester resin having a glass transition temperature Tg of 50 to 75 ° C., and these polyester resins (A) The weight ratio with the polyester resin (B) is
(A) / (B) = 20/80 to 80/20,
When T1 / 2 temperatures are T1 / 2 (A) and T1 / 2 (B), respectively.
20 ° C. <T1 / 2 (B) −T1 / 2 (A) <100 ° C.
Those having the relationship are preferably used.
[0069]
Considering each temperature characteristic by the flow tester, the melting temperature T1 / 2 (A) of the resin (A) by the 1/2 method is an index for imparting sharp melt property and low temperature fixability. (A) is more preferably in the range of 80 to 115 ° C, particularly preferably in the range of 90 to 110 ° C.
[0070]
Resin (A) defined by these performances has a low softening temperature, and even in the fixing process using heat rolls, even when the heat energy applied is reduced by lowering the heat rolls or increasing the process speed, Melts and exhibits excellent performance in cold offset resistance and low temperature fixability.
[0071]
When the melting temperature T1 / 2 (B) and the outflow end temperature Tend (B) by the 1/2 method of the resin (B) are both too low, hot offset is likely to occur, and when it is too high, the particles T1 / 2 (B) is more preferably 125 ° C. to 210 ° C., and particularly preferably 130 ° C. to 200 ° C., because the particle size distribution at the time of formation deteriorates and the productivity is lowered.
[0072]
The resin (B) defined by these performances has a strong rubber elasticity and a high melt viscosity, so that the internal cohesive force of the melted toner layer is maintained even during heat melting in the fixing process, and hot offset occurs. It is difficult to resist and exhibits excellent friction resistance due to its toughness even after fixing.
[0073]
By blending the resin (A) and the resin (B) in a well-balanced manner, a toner that sufficiently satisfies offset resistance and low-temperature fixing performance in a wide temperature range can be provided.
[0074]
When the weight ratio (A) / (B) between the resin (A) and the resin (B) is too small, the fixing property is affected. When the weight ratio is too large, the offset resistance is affected. It is preferable that it is 80-80 / 20, and it is still more preferable that it is 30 / 70-70 / 30.
[0075]
Moreover, when the melting temperatures of the resin (A) and the resin (B) by the 1/2 method are T1 / 2 (A) and T1 / 2 (B), respectively, both low-temperature fixability and offset resistance can be achieved. From the point of view and in order to facilitate uniform mixing without causing problems due to the difference in viscosity between the resins, the range of T1 / 2 (B) -T1 / 2 (A) exceeds 20 ° C. and 90 ° C. It is more preferable that the temperature is below 20 and 80 ° C. is particularly preferable.
[0076]
In the present invention, the glass transition temperature (Tg) in the present invention is a value obtained by measuring 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. It is.
[0077]
When the Tg of the polyester resin (A) is less than 40 ° C. or the Tg of the polyester resin (B) is less than 50 ° C., the resulting toner is blocked during storage or in a developing machine (toner particles are aggregated into a lump. This phenomenon is not preferable. On the other hand, if the Tg of the polyester resin (A) exceeds 70 ° C., or if the Tg of the polyester resin (B) exceeds 75 ° C., the toner fixing temperature increases, which is not preferable. As described above, by using the polyester resin (A) and the polyester resin (B) having the above relationship as the polyester resin as the binder resin, the obtained toner has better fixability, which is preferable. .
[0078]
Furthermore, the binder resin made of a polyester resin has a weight average molecular weight of 30,000 or more, preferably 37, as measured by gel permeation chromatography (GPC) method in which tetrahydrofuran (THF) is soluble. 000 or more, (2) weight average molecular weight (Mw) / number average molecular weight (Mn) is 12 or more, preferably 15 or more, and (3) the area ratio of components having a molecular weight of 600,000 or more, preferably 0.3% or more of the total In order to obtain good fixability, it is preferable that the area ratio of the component having a molecular weight of 0.5% or more and (4) molecular weight of 10,000 or less is 20 to 80%, preferably 30 to 70%. When blending a plurality of resins, the GPC measurement result of the final resin mixture may be within the above numerical range.
[0079]
In the polyester resin used in the production method of the present invention, a high molecular weight component having a molecular weight of 600,000 or more has a function of ensuring hot offset resistance. On the other hand, a low molecular weight component having a molecular weight of 10,000 or less is effective for lowering the melt viscosity of the resin, manifesting a sharp melt property and lowering the fixing start temperature, and may contain a resin component having a molecular weight of 10,000 or less. preferable. In order to obtain good thermal characteristics such as low-temperature fixing, hot offset resistance, and transparency in the oilless fixing method, it is preferable that the binder resin has such a broad molecular weight distribution.
[0080]
Here, the molecular weight of the THF-soluble component of the binder resin is determined by filtering the THF-soluble matter with a 0.2 μm filter, then using Tosoh GPC / HLC-8120, Tosoh column “TSKgel SuperHM-M” (15 cm) Are used, measured with a THF solvent (flow rate 0.6 ml / min, temperature 40 ° C.), and a molecular weight is calculated by using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.
[0081]
The acid value of the polyester resin (the number of mg of KOH required to neutralize 1 g of resin) is as follows: (1) it is easy to obtain the molecular weight distribution as described above, and (2) the granulation properties of fine particles by emulsification dispersion. (3) The environmental stability of the obtained toner (the stability of the chargeability when the temperature and humidity change) is easy to maintain, and the range of 1 to 20 mgKOH / g Is preferred. As mentioned above, the acid value of the polyester resin is not limited to the addition of monocarboxylic acid and / or monoalcohol to the polyester resin obtained by condensation polymerization of polyvalent carboxylic acid and polyhydric alcohol. It can adjust by controlling the carboxyl group of the terminal of polyester with the compounding ratio and reaction rate of a polybasic acid of this, and a polyhydric alcohol. Or what has a carboxyl group in the principal chain of polyester can be formed by using trimellitic anhydride as a polybasic acid component.
[0082]
In the production method of the present invention, a release agent can be used. In this case, the release agent is selected from the group of hydrocarbon waxes such as polypropylene wax, polyethylene wax, and Fischer-Tropsch wax, and natural ester waxes such as synthetic ester wax, carnauba wax, and rice wax. The mold release agent used is used. Of these, natural ester waxes such as carnauba wax and rice wax, and synthetic ester waxes obtained from polyhydric alcohols and long-chain monocarboxylic acids are preferably used. As the synthetic ester wax, for example, WEP-5 (manufactured by NOF Corporation) is preferably used. If the content of the release agent is less than 1% by weight, the releasability tends to be insufficient, and if it exceeds 40% by weight, the wax tends to be exposed on the surface of the toner particles, and the chargeability and storage stability decrease. Since it becomes easy, the inside of the range of 1 to 40 weight% is preferable.
[0083]
In the production method of 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 a positively chargeable charge control agent. As a control agent, it can be used 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 these positively chargeable charge control agents. In addition, as the negatively chargeable charge control agent, heavy metals such as trimethylethane dyes, salicylic acid metal complexes, benzylic acid metal complexes, copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex azo dyes, azochrome complexes, etc. Examples thereof include acidic dyes, calixarene-type phenol condensates, cyclic polysaccharides, resins containing carboxyl groups and / or sulfonyl groups, and the like.
[0084]
The content of the charge control agent is preferably 0.01 to 10% by weight. In particular, the content is preferably 0.1 to 6% by weight.
[0085]
There is no restriction | limiting in particular about the coloring agent used for the manufacturing method of this invention, Although a well-known and usual thing is used, A pigment is used suitably especially. Examples of the black pigment include carbon black, cyanine black, aniline black, ferrite, and magnetite. Moreover, what mix | blended the following chromatic pigment so that it might become black can also be used.
[0086]
Examples of yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, ocher, titanium yellow, naphthol yellow S, Hansa Yellow 10G, Hansa Yellow 5G, Hansa Yellow G, Hansa Yellow GR, Hansa Yellow A, Hansa Yellow RN, Hansa Yellow R, Pigment Yellow L, Benzidine Yellow, Benzidine Yellow G, Benzidine Yellow GR, Permanent Yellow NCG, Vulcan First Yellow 5G, Vulcan First Yellow R, Quinoline Yellow Lake, Anslagen Yellow 6GL, Permanent Yellow FGL, Permanent Yellow H10G, Permanent Yellow HR, Anthrapyrimidine Yellow, Other Isoindolinone Yellow, Chromophthal Yellow, Novo Palm Yellow H2G Condensation azo yellow, nickel azo yellow, copper azomethine yellow, etc..
[0087]
Examples of red pigments include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, Indanthrene Brilliant Orange RK, Indanthrene Brilliant Orange GK, Benzidine Orange G, Permanent Red 4R, Permanent Red BL, and Permanent Red. F5RK, Resol Red, Pyrazolone Red, Watching Red, Lake Red C, Lake Red D, Brilliant Carmine 6B, Brilliant Carmine 3B, Rhodamine Lake B, Alizarin Lake, Permanent Carmine FBB, Verinone Orange, Isoindolinone Orange, Anthanthrone Orange , Pilanthrone Orange, Quinacridone Red, Quinacridone Magenta, Quinacridone Scarlet, Perille Red and the like.
[0088]
Examples of blue pigments include cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, fanatone blue 6G, Victoria blue rake, metal-free phthalocyanine blue, copper phthalocyanine blue, first sky blue, indanthrene blue RS, and indanthrene. Blue BC, Indico etc. are mentioned.
[0089]
The amount of these colorants used is preferably in the range of 1 to 50 parts by weight and particularly preferably in the range of 2 to 15 parts by weight per 100 parts by weight of the binder resin.
[0090]
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 model.
[0091]
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.
[0092]
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.
[0093]
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.
[0094]
Among these, silicon resin and (meth) acrylic resin are particularly excellent in charging 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 silicon, 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 during coating.
[0095]
The method of coating the resin on the surface of the carrier core is not particularly selected, but an immersion method in which the resin is coated in a solution of the coating resin, a spray method in which the coating resin solution is sprayed on the surface of the carrier core, or a carrier with flowing air A fluid bed method in which spraying is performed in a suspended state, and a kneader coater method in which a carrier core material and a coating resin solution are mixed in a kneader coater to remove the solvent.
[0096]
The solvent used in the coating resin solution is not particularly limited as long as it dissolves the coating resin. For example, toluene, xylene, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane and the like can be used. The thickness of the coating layer on the carrier surface is usually 0.1 to 3.0 μm.
[0097]
The resin-coated carrier is preferably heat-treated as necessary. In particular, coating with a resin containing a crosslinking component is preferable because the film is strengthened by a thermal crosslinking reaction and becomes a carrier with higher durability.
[0098]
In addition, when heat treatment is performed, the charge amount when mixed with toner can be controlled according to the temperature condition. Generally, the higher the heating temperature, the higher the charge amount. Usually, the heat treatment is performed at a temperature of 100 ° C. to 300 ° C. for 10 minutes to 5 hours.
[0099]
And after heat processing, since carriers may have adhered, stress may be loosened and carrier particles may be loosened.
[0100]
The weight ratio between the hydrophobic silica treated with silicone oil and the resin-coated magnetic carrier is not particularly limited, but is usually 1 to 5 parts by weight of toner particles per 100 parts by weight of the carrier. When the amount is less than 1 part by weight, triboelectric charging becomes advantageous, so that the charge amount increases and the number of differently charged particles decreases, but the transfer amount decreases, which is not preferable. On the other hand, if it exceeds 5% by weight, frictional charging becomes insufficient, and a tendency such as a decrease in rising of charging and an increase in differently charged particles is observed, which is not preferable.
[0101]
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 cargo image carrier 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.
[0102]
The heat roll used here preferably does not use an anti-offset liquid. The release layer of the heat roll preferably contains a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer. When using an anti-offset solution, in addition to maintenance problems, silicone oil and other substances may be transferred to printing paper and OHP sheets, which may cause problems such as writing after printing or oil stickiness. It is preferable not to use an offset prevention liquid. Further, when the release layer of the heat roll contains a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, fatigue deterioration of the fixing roll can be prevented and the life of the fixing device itself can be extended. In addition, since the releasability is high, offset can be prevented without using an offset prevention liquid, and good fixing can be achieved.
[0103]
【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 “part by weight” and “water” means deionized water.
[0104]
(Example of polyester resin synthesis)
Trimellitic anhydride (TMA) as the polyvalent carboxylic acid, terephthalic acid (TPA) and 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 based on the total amount of monomers, and a thermometer, a stirring rod, a condenser, and a nitrogen introduction tube are provided at the top of the flask. 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.
[0105]
[Table 1]

> 600,000; area ratio of components having a molecular weight of 600,000 or more
<10,000: Area ratio of components with a molecular weight of 10,000 or less
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
BA: Benzoic acid
TMP; trimethylolpropane
FT value; Flow tester value
[0106]
In Table 1, the “T1 / 2 temperature” is a nozzle diameter of 1.0 mmΦ × 1.0 mm, unit area (cm) using a flow tester (CFT-500) manufactured by Shimadzu Corporation as described above.² ) Is a value measured at a heating rate of 10 kg per minute and 6 ° C. per minute. Further, “Tg” (° C.), which is a glass transition temperature, is a value measured at a rate of temperature increase of 10 ° C. per minute by a second run method using a differential scanning calorimeter (DSC-50) manufactured by Shimadzu Corporation.
[0107]
(Example of preparation of mold release agent dispersion)
Carnauba wax “Carnauba wax No. 1” (Yoko Kato imported product) 50 parts and 50 parts of polyester resin (R1 in Table 1) were kneaded with a pressure kneader, and the kneaded product and 185 parts of methyl ethyl ketone were charged into a ball mill. After stirring for a period of time, it was taken out and the solid content was adjusted to 20% by weight to obtain a release agent fine dispersion (W1). In the same manner, a release agent dispersion (W2) was obtained using polyester resin R2.
[0108]
(Preparation of colorant master chip and preparation example of colorant dispersion)
Carbon black and a color pigment were kneaded at a weight ratio of 50/50 with a resin in the composition shown in Table 2 to prepare colorant master chips P1 to P5. Carbon black and resin were kneaded using a pressure kneader. Further, the color pigment and the resin were kneaded with two rolls. The obtained kneaded materials P2 to P4 were charged into a ball mill together with methyl ethyl ketone so that the solid content was 40% by weight, stirred for 36 hours, and then taken out. The solid content was adjusted to 20% by weight, and P2 to P4 The colorant dispersion was obtained.
[0109]
[Table 2]

The colorants shown in Table 2 are as follows.
Carbon: “ELFTEX-8” (Cabot)
Cyan pigment: Fast Gen Blue TGR (Dainippon Ink Chemical Co., Ltd.)
Yellow pigment: Shimla First Yellow 8GR (manufactured by Dainippon Ink & Chemicals, Inc.)
Magenta pigment: Fast Gen Super Magenta R (Dainippon Ink Chemical Co., Ltd.)
[0110]
(Preparation of wet kneading mill base)
The above mold release agent dispersion, colorant dispersion, dilution resin (additional resin), and methyl ethyl ketone were mixed with a Desper, and the solid content was adjusted to 55% to prepare mill bases (MB1 to MB5). Table 3 shows the formulation of the produced mill base.
[0111]
[Table 3]

> 600,000; area ratio of components having a molecular weight of 600,000 or more
<10,000: Area ratio of components with a molecular weight of 10,000 or less
[0112]
The properties of the blend resin used in Table 3 are shown in Table 4. The resin blend was obtained by blending resin particles having passed through 200 mesh at the above weight ratio and measuring each physical property value.
[0113]
[Table 4]

[0114]
Example 1
Add 545.5 parts of Millbase MB1 and 23.8 parts of 1N ammonia water to a cylindrical 2 L separable flask with Max Blend blade as a stirring blade, and thoroughly stir at 350 rpm with a three-one motor. 133 parts of water was added and further stirred to adjust the temperature to 30 ° 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 1.19 m / s. Next, the amount of solvent was adjusted by adding 333 parts of deionized water.
[0115]
Next, after adding 4.1 parts of Epan 450 (Daiichi Kogyo Seiyaku Co., Ltd.), a nonionic emulsifier, diluted in water, the temperature was adjusted to 30 ° C. and the rotational speed was adjusted to 250 rpm. 410 parts of an aqueous solution of ammonium sulfate was added dropwise to adjust the amount of solvent in the dispersion to 15.5% by weight. Thereafter, stirring was continued for 5 minutes under the same conditions to complete the coalescence operation. The peripheral speed of the stirring blade at this time was 0.85 m / s. The resulting slurry was subjected to solid-liquid separation and washing with a centrifugal separator, and then dried with a vacuum dryer to obtain toner particles. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0116]
(Example 2)
Toner particles were produced in the same manner as in Example 1 except that the coalescence operation for 5 minutes in Example 1 was changed to 70 minutes. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0117]
(Example 3)
After the nonionic emulsifier is diluted in water and added, the stirring device is changed to “TK Robotics” (a homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.), the rotation speed is adjusted to 8000 rpm, and the coalescence operation is performed for 20 minutes. Toner particles were produced in the same manner as in Example 1 except that The peripheral speed of the stirring blade at this time was 12.56 m / s. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0118]
(Example 4)
Toner particles were produced in the same manner as in Example 2 except that MB1 in Example 2 was changed to MB2. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0119]
(Example 5)
Toner particles were produced in the same manner as in Example 2 except that MB1 in Example 2 was changed to MB3. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0120]
(Example 6)
Toner particles were produced in the same manner as in Example 2 except that MB1 in Example 2 was changed to MB4. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0121]
(Example 7)
Toner particles were produced in the same manner as in Example 2 except that MB1 in Example 2 was changed to MB5. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0122]
(Example 8)
Toner particles were produced in the same manner as in Example 2, except that MB1 in Example 2 was changed to MB6. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0123]
(Comparative Example 1)
Add 545.5 parts of Millbase MB1 and 23.8 parts of 1N ammonia water to a cylindrical 2 L separable flask with Max Blend blade as a stirring blade, and thoroughly stir at 350 rpm with a three-one motor. 133 parts of water was added and further stirred to adjust the temperature to 30 ° 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 1.19 m / s. Next, 500 parts of deionized water was added to adjust the amount of solvent.
[0124]
Next, without adding an emulsifier (dispersion stabilizer), the temperature was adjusted to 30 ° C. and the rotation speed was adjusted to 250 rpm, and 410 parts of a 3% ammonium sulfate aqueous solution was added dropwise to make the amount of the solvent 15.5 wt%. As a result, the entire fine particles aggregated during the dropping, and the particles could not be taken out.
[0125]
(Comparative Example 2)
Toner particles were obtained in the same manner as in Example 3 except that the nonionic emulsifier and the aqueous solution of ammonium sulfate used in Example 3 were not used. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0126]
(Comparative Example 3)
Add 545.5 parts of Millbase MB1 and 23.8 parts of 1N ammonia water to a cylindrical 2 L separable flask with Max Blend blade as a stirring blade, and thoroughly stir at 350 rpm with a three-one motor. 133 parts of water was added and further stirred to adjust the temperature to 30 ° 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 1.19 m / s. Next, after adding 200 parts of deionized water, the organic solvent was removed under reduced pressure until the solid content was 40%. The amount of solvent at this time was 1% or less. The dispersion was then diluted to adjust the solid content to 15%.
[0127]
A similar stirring device and flask were charged with 1000 parts of the above dispersion, and after adjusting the temperature to 30 ° C. and the rotation speed to 250 rpm, 0.75 parts of NL-250 (Daiichi Kogyo Seiyaku Co., Ltd.), a nonionic emulsifier. Was diluted with water and then 150 parts of a 10% aqueous ammonium sulfate solution was added.
[0128]
At this time, the aggregated fine particles were sampled and observed with a microscope, and it was observed that spherical or substantially spherical fine particles were in contact with each other and aggregated. There was no sign that the particles were fused and integrated. Moreover, when the sampled aggregated particles were washed with water, it was observed that the individual fine particles fell apart and the aggregates were loosened. Therefore, it can be seen that the aggregate of fine particles at this point is an aggregate of fine particles, and is not an aggregate formed by coalescence in the production method of the present invention.
[0129]
Thereafter, the temperature was raised at 10 ° C./min, and after stirring at 80 for 2 hours, 1.5 parts of NL-250 (Daiichi Kogyo Seiyaku Co., Ltd.) was diluted with water and added, and the temperature was further raised to 90 ° C. The stirring was continued for 7 hours, and the coagulation / fusion operation was completed. The peripheral speed of the stirring blade at this time was 0.85 m / s. The resulting slurry was subjected to solid-liquid separation and washing with a centrifugal separator, and then dried with a vacuum dryer to obtain toner particles. As described above, the toner particles of this comparative example are toner particles produced by long-time treatment at a high temperature. The properties of the obtained toner particles are shown in Tables 5 and 6.
[0130]
[Table 5]

[0131]
[Table 6]

[0132]
The particle size and particle size distribution in Table 6 were measured using a Coulter Multisizer II 100 micron aperture tube from Coulter Beckman. Dv50 is a 50% volume average diameter, and Dv50 / Dn50 is a ratio of volume and number 50% average diameter. GSD is the square root of a value obtained by dividing the 84% volume average diameter by the 16% volume average diameter. The circularity distribution was measured using a flow type particle image analyzer FPIP-1000 manufactured by Toa Medical Electronics Co., Ltd. Further, the yield is a value obtained by removing the solvent of the obtained toner particle dispersion and passing through a 530 mesh sieve and calculating by the following formula: 90-100%: ○, 80-90% Is Δ, and 60% or less is ×.
[0133]
Yield (%) = {(solid content of mill base charged) − (solid content of residue on sieve)} × 100 / (solid content of mill base charged)
[0134]
[Table 7]

[0135]
Using a Henschel mixer, 100 parts of toner particles of each Example and Comparative Example were mixed with 0.5 part of hydrophobic silica (H-2018 manufactured by Clariant Co., Ltd.) and titanium oxide (JMT-150AO manufactured by Teika Co., Ltd.). ) 0.5 part was externally added to obtain an electrostatic image developing toner (hereinafter referred to as powder toner). The thermal characteristics and image characteristics of the obtained powder toner were evaluated by the following evaluation methods, and the measurement results are shown in Table 7.
[0136]
With respect to the fixing temperature range, the fixing temperature was determined by the following fixing property test and indicated by the range between the upper limit value and the lower limit value.
[0137]
(Fixability test)
Each powder toner using the toner particles produced in each Example and each Comparative Example was used to develop an unfixed test pattern with a commercially available copying machine using a non-magnetic two-component development system. This printing paper is fixed at a speed of 90 mm / second by passing through a Ricoh Imagio DA-250 heat roll (using the surface of the upper heat roll coated with a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), The surface temperature of the heat roll when the cellophane is pasted on the image after fixing and the ID (image density) after peeling is 90% or more of the original ID and no occurrence of offset is observed is “fixing temperature”. did. From the results shown in Table 7, it was confirmed that in the examples of the present invention, both the fixing start temperature and the hot offset temperature were good under oilless fixing conditions in which no oil application was performed.
[0138]
(Image output test)
Each powder toner was imaged using a commercially available non-magnetic two-component developing type copying machine and non-magnetic one-component printer. The fogging, gradation, and resolution of the obtained image were evaluated, and “Good” was indicated by “◯”, “Slightly inferior” by “Δ”, and “Inferior” indicated by “X”.
[0139]
(Evaluation method of OHP sharpness (color transparency))
An unfixed image with color toners using the toner particles of Examples 4 to 6 was formed on an OHP sheet, and the unfixed image was fixed by a separately prepared fixing tester. Fixing was conducted by passing through a Ricoh Imagio DA-250 heat roll (oilless type: coated with a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) at a heat roll temperature of 160 ° C. and a speed of 90 mm / sec. An OHP sheet printed in black was placed on the OHP sheet created in the above procedure, and projected onto a screen with an overhead projector, and the sharpness of characters was visually evaluated. The evaluation results were expressed as “◯” when the characters were clearly visible, “Δ” when the characters were blurred, and “X” when the characters were not distinguishable.
[0140]
(Heat resistant storage stability evaluation)
Further, when each powder toner was subjected to a heat resistance blocking test at 50 ° C. for 3 days, no aggregation was observed in all the toners.
[0141]
In each Example, it turns out that a spherical particle can be manufactured with sufficient productivity in a short time. Also, it can be seen that the distribution of each particle is very sharp. Moreover, when the result of Table 7 is seen, it turns out that all show favorable fixability on oilless conditions. In Example 3, the generation of fine particles and coarse particles is larger than in other examples, and the distribution is slightly wider. This is because the homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), which is a high-speed disperser with a combination of a stator and a rotor, was used for coalescence at high shear, resulting in the generation of fine particles due to particle crushing and non-uniform stirring. This is due to the generation of coarse particles. Since Comparative Example 1 did not use an emulsifier, coalescence could not be controlled, and the intended toner particles could not be obtained. In Comparative Example 2, coalescence was performed with a high shearing force without using an emulsifier and an electrolyte, but many fine particles and coarse particles were generated. You can't get it. Comparative Example 3 is a method for producing particles consisting of two stages of agglomeration and fusion processes, but it takes a high temperature and a lot of time to fuse and spheroidize, and productivity is an example of the present invention. It turns out that it is inferior in comparison.
[0142]
【The invention's effect】
As described above, according to the production method of the present invention, an electrolyte is added in the presence of a dispersion stabilizer, and toner particles are obtained by coalescence. Therefore, there is no emulsification loss, high yield, and particle size distribution. Toner particles having a sharp polyester resin as a binder resin can be obtained. In addition, since toner particles are obtained by coalescence, a manufacturing method excellent in productivity that can be manufactured in a short time without heating spherical or substantially spherical particles is provided.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining how to obtain a flow tester value, (a) is a side sectional view showing an outline of a measuring apparatus, and (b) is a method for obtaining each flow tester value from the measured value. It is a graph for.

Claims (9)

A first step of forming fine particles of the mixture in the aqueous medium by emulsifying the mixture containing at least the polyester resin and the organic solvent in the aqueous medium;
Then, a dispersion stabilizer is added, and a second step of producing an aggregate of the fine particles by coalescing the fine particles by sequentially adding an electrolyte,
After removing the organic solvent contained in the aggregate, the toner is manufactured by sequentially performing a third step of separating and washing the aggregate of fine particles from the aqueous medium, and then drying the aggregate. A method for producing a toner for developing an electrostatic image. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the second step is performed at 10 to 50C. 3. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the amount of the solvent in the system after the addition of the electrolyte is 5 to 25% by weight. 4. The method for producing a toner for developing an electrostatic charge image according to claim 1 , wherein the first step is performed by a production apparatus having a stirring blade whose tip rotates at a peripheral speed of 0.2 to 10 m / s. 5. . 5. The electrostatic image developing toner according to claim 1 , wherein the second step is performed by a production apparatus having a stirring blade whose tip rotates at a peripheral speed of 0.2 to 10 m / s. Production method. The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 , 2, 3, 4 and 5, wherein the electrolyte is a sulfate compound containing a monovalent cation. The polyester resin has a T1 / 2 temperature of 120 to 160 ° C. measured by a constant load extrusion type capillary rheometer, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 12 or more. The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 , 2, 3, 4, 5, and 6 . The electrostatic charge image according to any one of claims 1 , 2, 3, 4, 5, 6 and 7, wherein the polyester resin contains a plurality of polyester resins having different T1 / 2 temperatures measured by a constant load extrusion type capillary rheometer. A method for producing a developing toner. The method for producing a toner for developing an electrostatic charge image according to claim 1 , wherein the mixture contains a release agent.

Images