JP3984755B2 - Toner production method - Google Patents

Description

【００４６】
先ず、上記処方のうち、Ｃ．Ｉ．ピグメントレッド１２２、サリチル酸金属化合物及びスチレン単量体１００重量部を、アトライター（三井三池化工機製）を用いて３時間分散し、着色剤分散液を得た。次に、得られた着色剤分散液に、上記処方の残りすべてを添加し、６０℃に加温して３０分間溶解混合した。これに、重合開始剤である２，２’−アゾビス（２，４−ジメチルバレロニトリル）１０重量部を溶解し、重合性単量体組成物を調製した。次に、得られた重合性単量体組成物を、先に調製した水系分散媒中に投入し、回転数を維持しつつ１５分間造粒した。その後、高速攪拌機からプロペラ攪拌羽根に攪拌機を変え、内温を８０℃に昇温させ、５０回転／分で重合を１０時間継続させた。次いで内温８０℃、装置内圧力４７．３ｋＰｓの条件下で、４ｈｒ．蒸留を行なった。蒸留終了後、スラリーを冷却し、希塩酸を添加し、Ｃａ₃(ＰＯ₄)₂を溶解させた後、濾過、水洗、次いで解砕を行って、含水率１５％の湿潤着色重合体粒子を得た。
この時点で湿潤着色重合体粒子に残留している重合性単量体の量を測定したところ、４２０ｐｐｍであった。
【００４７】
上記で得られた含水率１５％の湿潤着色重合体粒子に対して、連続瞬間気流乾燥機（フラッシュドライヤーＦＪＤ−４：セイシン企業社製、配管長２ｍ）を用いて予備的な乾燥を行った。このときの乾燥条件としては、６０℃の空気を４２０ｍ³／ｈｒで吹き込み、湿潤着色重合体粒子を７０ｋｇ／ｈｒで連続的に供給した。この予備的な乾燥終了後に得られた着色重合体粒子の含水率を測定したところ、その含水率は４．３％であった。又、この時点で着色重合体粒子（トナー）に残留している重合性単量体の量を測定したところ、４１０ｐｐｍであり、その重量平均粒子径は７．９μｍであった。
【００４８】
次に、上記のようにして予備乾燥された着色重合体粒子を被乾燥物として、下記の方法で乾燥した。乾燥装置として、ループ形状の、配管長が２ｍの乾燥管を有する図１に記載の乾燥装置を用いた。乾燥条件としては、８０℃の空気を４２０ｍ³／ｈｒで吹き込み、被乾燥物である着色重合体粒子を、６２ｋｇ／ｈｒで連続的に供給した。乾燥終了時点で、含水率を測定したところ、その含水率は０．３％であった。即ち、単位時間当たりの蒸発水分量（Ａ₁）と単位時間当たりに送り込む熱風の重量（Ａ₂）の比（Ａ₁／Ａ₂）が、０．００６１となる条件で連続的に供給したことになる。又、乾燥後の着色重合体粒子に残留している重合性単量体の量は、１８０ｐｐｍであった。
【００４９】
更に、上記で得られたトナー（着色重合体粒子）１００重量部に対し、ＢＥＴ法による比表面積が２００ｍ²／ｇである疎水性シリカ１．５重量部を外添して現像剤とした。
この現像剤を用いて、キヤノン製カラーレーザージェットプリンター カラーレーザーショット−２０３０の改造機を用いて、２３℃／６５％ＲＨの環境下で画出し試験を行ったところ、５，０００枚耐久においても、初期と耐久後の画像濃度に変化がなく、中抜けのない高画質画像が得られた。又、有機半導体である感光体に対するトナー融着やメモリーゴーストのような問題も生じなかった。更に、両面画像を形成させたが、転写材の表裏面共にオフセットの発生は認められなかった。又、ＯＨＰシートへの画像形成を行ったところ、透明性の良好な画像が得られた。
又、３０℃／８０％ＲＨの環境下で同様な画出し試験を行ったところ、同様に良好な結果が得られた。
【００５０】
実施例２
予備的乾燥までは実施例１と同様にして、含水率が４．３％に調製された着色重合体粒子を得、これを被乾燥物とし、ループ形状の配管長が８ｍの乾燥管を有する図１に記載の構成を有する乾燥装置を用いて乾燥を行った。尚、乾燥条件は、実施例１と同様にして行った。この結果、得られた着色重合体粒子（トナー）の含水率は、０．１％であった。又、残留している重合性単量体の量を測定したところ、６０ｐｐｍであった。
上記で得られたトナー（着色重合体粒子）を用い、実施例１と同様にして現像剤を調製した。この現像剤を用いて実施例１と同様の画出し評価を行ったところ、実施例１と同様に良好な画出し結果が得られた。
【００５１】
実施例３
解砕までは実施例１と同様にして得られた含水率１５％の湿潤着色重合体粒子を、ループ形状の配管長が２ｍの乾燥管を有する連続瞬間気流乾燥機（フラッシュドライヤーＦＪＤ−４：セイシン企業社製）を用いて予備乾燥を行った。この時の乾燥条件としては、６０℃の空気を４２０ｍ³／ｈｒで吹き込み、湿潤着色重合体粒子を５０ｋｇ／ｈｒで連続的に供給した。このようにして予備乾燥した着色重合体粒子の含水率を測定したところ、２．８％であった。又、この時点で着色重合体粒子に残留している重合性単量体の量を測定したところ４００ｐｐｍであり、又、重量平均粒子径は７．７μｍであった。
次に、予備乾燥された着色重合体粒子を取り出して被乾燥物とし、実施例１と同様の乾燥装置を用い、同様の乾燥条件で乾燥をしたところ、乾燥後の含水率は０．２％であり、又、着色重合体粒子に残留している重合性単量体の量は１５０ｐｐｍであった。
このようにして得られたトナー（着色重合体粒子）を用い、実施例１と同様にして現像剤を調製した。この現像剤を用いて実施例１と同様の画出し評価を行ったところ、実施例１と同様に良好な画出し結果が得られた。
【００５２】
実施例４
解砕までは実施例１と同様にして得られた含水率１５％の湿潤着色重合体粒子を用い、ループ形状の配管長が２ｍの乾燥管を有する連続瞬間気流乾燥機（フラッシュドライヤーＦＪＤ−４：セイシン企業社製）を用いて予備乾燥を行った。乾燥条件として、６０℃の空気を４２０ｍ³／ｈｒで吹き込み、着色重合体粒子を２５ｋｇ／ｈｒで連続的に供給した。予備乾燥を終了した時点での含水率は０．６％であった。又、予備乾燥がされた着色重合体粒子に残留している重合性単量体の量は、３９５ｐｐｍであった。又、重量平均粒子径は７．２μｍであった。
次に、上記のようにして予備乾燥された着色重合体粒子を被乾燥物とし、実施例１で使用したと同様の乾燥装置を用い、同様の条件で乾燥を行ったところ、乾燥後の着色重合体粒子含水率は０．２％であり、又、着色重合体粒子に残留している重合性単量体の量は１００ｐｐｍであった。
この着色重合体粒子（トナー）を用い、実施例１と同様にして現像剤を調製した。そして、この現像剤を用いて実施例１と同様の画出し評価を行ったところ、実施例１と同様に良好な画出し結果が得られた。
【００５３】
実施例５
予備乾燥までは実施例１と同様にして得られた含水率４．３％の着色重合体粒子を、実施例１と同様の乾燥装置を用いて乾燥を行った。乾燥条件として、８０℃の空気を４２０ｍ³／ｈｒで吹き込み、着色重合体粒子を４４ｋｇ／ｈｒで連続的に供給した。乾燥終了時点で、含水率は０．２％であった。即ち、本実施例では、表１に示したように、単位時間当たりの蒸発水分量（Ａ₁）と単位時間当たりに送り込む熱風の重量（Ａ₂）の比（Ａ₁／Ａ₂）が、０．００４４となる条件で連続的に供給したことになる。又、着色重合体粒子に残留している重合性単量体の量は１５５ｐｐｍであった。
このトナー（着色重合体粒子）を用い、実施例１と同様にして現像剤を調製した。そして、この現像剤を用いて実施例１と同様の画出し評価を行ったところ、実施例１と同様に良好な画出し結果が得られた。
【００５４】
実施例６
予備乾燥までは実施例１と同様にして得られた含水率４．３％の着色重合体粒子を、実施例１と同様の乾燥装置を用いて乾燥を行った。その際の乾燥条件として、８０℃の空気を４２０ｍ³／ｈｒで吹き込み、着色重合体粒子を２９ｋｇ／ｈｒで連続的に供給した。乾燥終了後の時点での含水率は０．２％であった。即ち、本実施例では、表１に示したように、単位時間当たりの蒸発水分量（Ａ₁）と単位時間当たりに送り込む熱風の重量（Ａ₂）の比（Ａ₁／Ａ₂）が、０．００２９となる条件で連続的に供給したことになる。又、着色重合体粒子に残留している重合性単量体の量は１３０ｐｐｍであった。
このトナー（着色重合体粒子）を用いて、実施例１と同様にして現像剤を調製した。この現像剤を用いて、実施例１と同様の画出し評価を行ったところ、実施例１と同様に良好な画出し結果が得られた。
【００５５】
比較例１
解砕までは、実施例１と同様にして得られた含水率１５％の湿潤着色重合体粒子を、棚段式熱風乾燥機を用いて、設定温度４０℃の条件下で３日間乾燥を行った。乾燥後に得られた着色重合体粒子（トナー）の含水率は０．２％であり、含有している重合性単量体の量は５０ｐｐｍであったが、着色重合体粒子の凝集によるダマの発生がみられた。
この得られたトナー（着色重合体粒子）を用い、実施例１と同様にして現像剤を調製した。この現像剤を用いて、実施例１と同様の画出し試験を行ったところ、５００枚程度から転写不良によるベタ部白抜けが発生し、２，０００枚程度から画像濃度の低下がみられた。更に、３０℃／８０％ＲＨの環境下２，０００枚程度で感光体へのトナー融着による画像欠陥が発生した。
【００５６】
比較例２
解砕までは実施例１と同様にして得られた含水率１５％の湿潤着色重合体粒子約４０ｋｇを、流動層乾燥機（ＦＢＳ−５型：大川原製作所社製）を用いて乾燥を行った。乾燥条件として、５０℃の空気を線速度０．４ｍ／秒で吹き込み、４時間後に着色重合体粒子を取り出して含水率を測定したところ、０．１％であった。又、この際に、着色重合体粒子に残留している重合性単量体の含有量は、８０ｐｐｍであった。しかし、着色重合体粒子の凝集によるダマの発生が見られた。
又、乾燥機内壁部には、着色重合体粒子の付着層がみられた。この付着層を取り出して含水率を測定したところ、０．１％であったが、この着色重合体粒子に残留している重合性単量体の含有率は、３３０ｐｐｍであり、残存量が多いことがわかった。
この得られたトナー（着色重合体粒子）を用いて、実施例１と同様にして現像剤を調製した。この現像剤を用いて、実施例１と同様の画出し試験を行ったところ、１，５００枚程度から転写不良によるベタ部白抜けが発生し、３０℃／８０％ＲＨの環境下４，０００枚程度で感光体へのトナー融着による画像欠陥が発生した。
【００５７】
比較例３
解砕までは実施例１と同様にして得られた含水率１５％の湿潤着色重合体を、予備的乾燥を行わずに、ループ形状の配管長が２ｍの乾燥管を有する図１に記載の乾燥装置を用いて乾燥を行った。尚、この際の乾燥条件としては、実施例１と同様に、８０℃の空気を４２０ｍ³／ｈｒで吹き込み、着色重合体粒子を６２ｋｇ／ｈｒで連続的に供給した。この時点での含水率は１．８％であり、従って、本比較例では、単位時間当たりの蒸発水分量（Ａ₁）と単位時間当たりに送り込む熱風の重量（Ａ₂）の比（Ａ₁／Ａ₂）が０．０２で、連続的に被乾燥物が供給されたことになる。又、着色重合体粒子に残留している重合性単量体の量は４１０ｐｐｍであり、乾燥後にあっても殆ど残留していることがわかった。
この得られたトナー（着色重合体粒子）を、実施例１と同様にして現像剤を調製した。この現像剤を用いて、実施例１と同様の画出し試験を行ったところ、１，０００枚程度から転写不良によるベタ部白抜けが発生し、３，５００枚程度から画像濃度の低下がみられた。更に、３０℃／８０％ＲＨの環境下、３，０００枚程度で感光体へのトナー融着による画像欠陥が発生した。
【００５８】
比較例４
解砕までは実施例１と同様にして得られた含水率１５％の湿潤着色重合体粒子を、予備的な乾燥を行わずに、実施例２と同様に、ループ形状の配管長が８ｍの乾燥管を有する図１に記載の乾燥装置を用いて乾燥を行った。尚、乾燥条件は、実施例１と同様に、８０℃の空気を４２０ｍ³／ｈｒで吹き込み、着色重合体粒子を６２ｋｇ／ｈｒで連続的に供給した。乾燥終了の時点で含水率を測定したところ、含水率は０．６％であった。従って、本比較例では、単位時間当たりの蒸発水分量（Ａ₁）と単位時間当たりに送り込む熱風の重量（Ａ₂）の比（Ａ₁／Ａ₂）が０．０２２で、連続的に供給されたことになる。又、乾燥後に着色重合体粒子に残留している重合性単量体の量は４００ｐｐｍであり、乾燥後にあっても殆ど残留していることがわかった。
この得られたトナー（着色重合体粒子）を、実施例１と同様にして現像剤を調製した。この現像剤を用いて、実施例１と同様の画出し試験を行ったところ、１，０００枚程度から転写不良によるベタ部白抜けが発生し、２，０００枚程度から画像濃度の低下がみられた、更に３０℃／８０％ＲＨの環境下２，５００枚程度で感光体へのトナー融着による画像欠陥が発生した。
【００５９】
以下に、実施例及び比較例で行った乾燥条件及び結果を下記表１にまとめて示した。
【表１】

【００６０】
【表２】

【００６１】
【発明の効果】
以上説明したように、本発明によれば、重合法によって得られた湿潤状態のトナー粒子を乾燥させる場合に、未反応の重合性単量体を均一に除去でき、しかも熱を長時間受けることなく、効率のよい乾燥を実現できるトナーの製造方法が提供される。この結果、残留する未反応の重合性単量体に起因する画像欠陥の生じることのない高画質画像の形成が可能なトナーが得られる。
【図面の簡単な説明】
【図１】本発明に用いられる被乾燥物を熱気流中で粉粒状に分散させ、高速気流と並流に送りながら乾燥する装置のシステムの一例を示す概略的図である。
【符号の説明】
１．ブロアー
２．熱風発生装置
３．気流分散部
４．気流抜き出し口
５．気流乾燥管
６．被乾燥物供給装置
７．サイクロン
８．乾燥品取り出し口
９．バッグフィルタ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner used in an image forming method for developing a latent image and a toner manufacturing method used in a toner jet type image forming method.
[0002]
[Prior art]
As described in U.S. Pat. No. 2,297,691, etc., a number of methods are known for electrophotography, and generally, on a photoconductor using a photoconductive substance, An electric latent image is formed by various means, and then the latent image is developed with toner. The obtained toner image is transferred to a transfer material such as paper selected as necessary, and then heated. A copy is obtained by fixing with pressure, solvent vapor or the like. At this time, as a method for developing a latent image using toner or a method for fixing a toner image, various methods have been proposed and methods suitable for the respective image forming processes have been adopted.
[0003]
Conventionally, as a general method for producing a toner used for these purposes, a colorant such as a dye and a pigment is melt-mixed in a thermoplastic resin and uniformly dispersed to form a resin colorant dispersion. A so-called pulverization method is used in which a toner having a desired particle size is obtained by pulverization and classification by a fine pulverizer and a classifier. According to such a production method, a toner having considerably excellent characteristics can be produced, but there is a certain limitation, that is, a selection range of a toner material. For example, the resin colorant dispersion was sufficiently brittle and had to be capable of being finely pulverized with economically possible production equipment.
However, if the resin colorant dispersion is made brittle in order to satisfy these requirements, the particle size range of the formed particles tends to be widened when actually pulverized at high speed, and a relatively large proportion of fine particles are formed. The problem of being included in this arises. Furthermore, when the toner made of such a brittle material is mounted on a copying machine or the like and used for development, the toner is more susceptible to further pulverization or pulverization and is not suitable for forming a high-quality image. there were. In this method, it is difficult to completely disperse solid fine particles such as a colorant in the resin, and depending on the degree of dispersion, the fog increases, the image density decreases, and the color mixing / transparency is poor. Had to pay attention to dispersal. In addition, exposure of the colorant to the fracture surface of the toner may cause a change in development characteristics.
[0004]
On the other hand, in order to overcome the problems of the toner by the pulverization method, toners by suspension polymerization method proposed in Japanese Patent Publication Nos. 36-10231, 43-10799, 51-14895, etc. Various polymerization toners and production methods thereof have been proposed. For example, in the suspension polymerization method, a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, and other additives are uniformly dissolved or dispersed to obtain a polymerizable monomer. After obtaining the monomer composition, the monomer composition is dispersed in a continuous phase containing a dispersion stabilizer, for example, an aqueous phase by using a suitable stirrer, and at the same time, a polymerization reaction is performed, and a desired composition is obtained. Toner particles having a particle size are obtained. Since this method does not include a pulverization process at all, the toner does not require brittleness, so a soft material can be used, and the classification process can be omitted, saving energy and reducing time. Cost reduction effect such as improvement in yield is great.
[0005]
In addition, in order to cope with the recent improvement in image quality, full color, energy saving, and the like of copiers and printers, the toner itself is required to have multiple functions. For example, with higher image quality, there is a demand for further finer particle diameters of toner particles that can support high resolution and digital systems, and with full color, there is a need for improved transparency of OHP images. Further, as energy saving, it is required to contain a low softening point substance in the toner in order to cope with low-temperature fixing, and as an effective means for improving the transfer efficiency to the transfer material, toner particles It is required to make the shape of the toner spherical, and the toner production method by the polymerization method is also effective as means for realizing these requirements.
[0006]
On the other hand, in general, in the polymerization method, including the polymerization method toner, the reaction form of the polymerization reaction system increases in viscosity as the polymerization progresses, and it becomes difficult to transfer radicals and polymerizable monomers. In addition, a large amount of unreacted polymerizable monomer components tend to remain. In particular, in the case of a suspension polymerization method toner, it is possible to suppress polymerization reactions such as dyes and pigments (particularly carbon black), charge control agents and magnetic substances in addition to polymerizable monomers in the polymerization reaction system. Because of the presence of a large amount of the reactive component, the unreacted polymerizable monomer is likely to remain.
[0007]
On the other hand, in the obtained toner particles, not only the unreacted polymerizable monomer but also a large number of components that act as a solvent for the binder resin, such as a residual organic solvent used as a dispersion medium, When the toner fluidity is lowered and used for image formation, there are problems that the image quality is deteriorated and the blocking resistance is lowered. In addition to this, particularly when an organic semiconductor is used as the photoconductor, there is a problem associated with the photoconductor deterioration phenomenon such as memory ghost and image blur in addition to the toner fusing phenomenon to the photoconductor drum. There is. Further, in addition to the matters relating to the performance of such products, there is also a problem that unreacted polymerizable monomer components volatilize and emit a bad odor during fixing.
[0008]
In order to improve the above problems, Japanese Patent Application Laid-Open No. 7-92736 discloses an improvement in image quality by reducing the residual amount of unreacted polymerizable monomer present in the toner particles to 500 ppm or less. It has been proposed to produce even more effects. However, with the downsizing and personalization of copiers and printers, the restrictions on the devices are increasing. From this point, the burden on the various problems described above is further increased, and the concern for the environment is also increasing. Therefore, it is preferable to reduce the remaining amount of the unreacted polymerizable monomer present in the toner particles to 200 ppm or less.
[0009]
As a method for setting the residual amount of polymerizable monomer in the toner particles to 200 ppm or less, a known means for promoting consumption of polymerizable monomer used when the binder resin is produced by a polymerization method can be used. . As a method for removing the unreacted polymerizable monomer, for example, a toner binder resin (polymer) is not dissolved, but a polymerizable monomer and / or an organic solvent component is dissolved. A method of washing with a solvent; a method of washing with an acid or an alkali; a solvent component that does not dissolve a foaming agent or a polymer is placed in a polymer system, and the resulting toner is made porous so that the unreacted toner existing inside the toner Examples include a method of increasing the volatilization area of the polymerizable monomer and / or organic solvent component; and a method of volatilizing the unreacted polymerizable monomer and / or organic solvent component under dry conditions. However, when these methods are used, the toner capsules may be deteriorated and the toner components may be eluted, or the solvent used for cleaning may remain in the toner. For this reason, it has been difficult to select an optimal solvent.
[0010]
Further, conventionally, toner particles obtained after solid-liquid separation of a suspension after the completion of the polymerization reaction are generally dried using a drying apparatus such as a shelf-type hot air dryer or a fluidized bed dryer. However, there are also problems that occur during the drying process as described below.
First, since the shelf-type hot air dryer dries toner particles in a stationary state, not only uneven drying occurs, but also the contact surface between the toner particles and hot air is small, resulting in extremely high drying efficiency. There is a problem that is bad. Further, from the viewpoint of reducing the unreacted polymerizable monomer present in the toner, generally, the boiling point of the unreacted polymerizable monomer is higher than that of water, so that the removal of water is not possible. In addition to being able to be removed effectively only after the completion, the shelf-type hot air dryer has a problem that a considerably long drying time is required when removal to 200 ppm or less is required. In this case, when the heat history applied to the toner becomes long, the deformation of the particles and the fusion of the particles are likely to occur, and as a result, the lumps due to the aggregation of the particles occur and the image characteristics are deteriorated.
[0011]
Further, since the drying of the toner particles by the fluidized bed dryer proposed in Japanese Patent Laid-Open Nos. 4-31966 and 8-179562 is direct contact with a hot air stream, the toner particles are efficiently obtained. Can be dried. However, it takes several hours to several tens of hours of drying time to sufficiently reduce the above-mentioned unreacted polymerizable monomer, although the degree is reduced compared with the above-described shelf-type hot air dryer. There is a problem that the deformation of the particles and the fusion of the particles occur, and as a result, the particles are agglomerated and the image characteristics are deteriorated.
[0012]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a toner manufacturing method that solves the problems of the prior art as described above.
More specifically, the object of the present invention is to uniformly remove unreacted polymerizable monomers when drying wet toner particles obtained by a polymerization method, and without being exposed to heat for a long time. It is an object of the present invention to provide a method for producing a toner which can obtain a toner capable of forming a high-quality image free from image defects due to residual unreacted polymerizable monomer by realizing good drying.
[0013]
[Means for Solving the Problems]
The above object is achieved by the present invention described below. That is, the present invention relates to a method for producing a toner in which the residual amount of unreacted polymerizable monomer present in toner particles is 200 ppm or less, and a polymerization method containing at least a polymerizable monomer and a colorant. After the wet monomer polymer composition is polymerized in an aqueous dispersion medium to produce wet colored polymer particles, the water content of the particles is adjusted to obtain colored polymer particles having a water content of 5.0% or less, Then, have a loop-type drying tube And a structure in which particles dried in the drying tube are classified and discharged, wherein an air flow outlet is provided inside the drying basket. Using an air dryer The And manufacturing the toner, wherein the obtained colored polymer particles are dispersed while being continuously fed into a high-speed hot air stream, and dried while being sent in parallel with the hot air stream to obtain toner particles constituting the toner. Is the method.
[0014]
In the present invention, when the moisture content of the wet colored polymer particles is further adjusted, the moisture content is 3.0% or less, preferably 1.0% or less, so that the moisture content is relatively dry. It is preferable that the colored polymer particles are obtained and the particles are dried in a hot air stream. In this way, it is possible to remove the unreacted polymerizable monomer remaining in the dried particles in a shorter time.
When the colored polymer particles are dried in a high-speed hot air stream, the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A) ₁ / A ₂ ) Is 0.008 or less, preferably 0.005 or less, more preferably 0.003 or less. If it does in this way, it will become possible to remove the unreacted polymerizable monomer which exists in colored polymer particles more efficiently.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to preferred embodiments.
As a result of intensive studies on the above-mentioned problems of the prior art, the present inventors have polymerized a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium to perform wet coloring. After producing the polymer particles, first, the water content of the obtained wet colored polymer particles is adjusted so that the water content is 5% or less, and then the obtained relatively dry colored polymer If particles are dispersed while being continuously fed into a high-speed hot air stream and dried while being sent in parallel with the hot air stream, the unreacted polymerizable monomer remaining in the toner particles can be efficiently dried in a short time. The present invention has been accomplished by finding that it can be well reduced.
[0016]
In particular, when the moisture content of the wet colored polymer particles is adjusted, the moisture content is preferably 3% or less, and more preferably after the moisture content is 1% or less and almost no moisture is present. If such wet colored polymer particles are configured to dry in a high-speed hot air stream, the drying efficiency is improved and the amount of unreacted polymerizable monomer remaining in the toner particles can be reduced in a shorter time. It was found that it can be reduced efficiently. Further, the drying of the colored polymer particles carried out in a high-speed hot air stream is carried out by the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A) ₁ / A ₂ ) Is 0.008 or less, preferably 0.005 or less, and more preferably 0.003 or less. Unreacted polymerizable monomer remaining in the toner particles It was also found that it can be reduced more efficiently.
[0017]
On the other hand, in the drying of wet colored polymer particles by a shelf-type hot air dryer, which has been performed by a conventional method for producing a polymerized toner, as described above, the unreacted polymerizable monomer is sufficiently removed. In order to reduce the abundance, it takes a very long drying time, and since the drying method dries the wet particles in a stationary state, there are places where it cannot come into contact with hot air, and evenly In some cases, the polymerizable monomer is not removed, resulting in a decrease in the performance of the developer containing the obtained toner as a constituent component.
[0018]
Even when drying is performed using a fluidized bed dryer having better drying efficiency, a long drying time is required to sufficiently remove the unreacted polymerizable monomer component from the wet colored polymer particles. In particular, particles with charging properties, such as toner particles, cause considerable charging due to friction caused by floating and flowing for a long time, resulting in adhesion of the flow chamber to the wall and further flow. Particles adhering to the wall surface of the chamber peeled off in a lump and became a source of lumps in the toner. When such lumps occur, in the subsequent step, when an external additive is added to the toner for the purpose of providing functionality, the external additive may not be uniformly attached to the toner particle surface, and as a developer. In some cases, there was a problem in performance.
[0019]
Hereinafter, each process of the toner manufacturing method of the present invention will be described in more detail.
In the method for producing a toner of the present invention, first, a polymerizable monomer composition comprising a toner forming material is polymerized in an aqueous dispersion medium to produce wet colored polymer particles. Next, the moisture content of the wet colored polymer particles is adjusted to obtain relatively dry colored polymer particles having a moisture content of 5.0% or less. In the present invention, the moisture content is preferably adjusted so that the water content is 3.0% or less, more preferably 1.0% or less. It is preferable to dry it while feeding it in parallel with the flow.
The moisture content in the present specification refers to the moisture content moisture content, that is, the ratio of the moisture weight to the total weight (the sum of the dry toner weight and the moisture weight), and was determined by a heat loss method at 105 ° C. Details thereof will be described later.
[0020]
Examples of the method for adjusting the moisture content of the wet colored polymer particles as described above include methods such as washing, dehydration, and preliminary drying.
Specifically, as a means for washing and dewatering wet colored polymer particles obtained by polymerizing the polymerizable monomer composition, for example, a method by filtration can be used. At this time, depending on the case, the material collected on the filter medium may be washed and dehydrated while sending air, or a method of taking a longer time for flowing air after dehydrating to some extent may be used. By these methods, particles having the above-mentioned specific water content can be easily obtained.
Furthermore, in order to obtain colored polymer particles having a specific water content, preliminary drying may be performed using a dryer. Of course, the methods listed above may be combined.
[0021]
Furthermore, in the method for producing a toner of the present invention, the colored polymer particles whose water content is adjusted by the method as described above are dispersed while being continuously fed into a high-speed hot air stream, and the particles are aligned with the hot air stream. Dry while flowing. A device that can be suitably used in this case, and that can be dried instantly while being dispersed in a granular state in a hot air stream and being sent in parallel with a high-speed air stream, is not particularly limited. It is more preferable to use an air dryer having a loop type drying tube 5 as shown in FIG. This will be described below.
[0022]
In the hot air dryer shown in FIG. 1, drying is performed as follows. First, the compressed air heated to a predetermined temperature by the hot air generator 2 is discharged from the airflow dispersion unit 3 at a high speed, and the material to be dried supplied from the raw material supply device 6 to the loop type airflow drying pipe 5 is removed. After being dispersed, the material to be dried is dried instantaneously (0.5 to several tens of seconds) in the airflow drying tube 5. Reference numeral 4 in the figure denotes an air flow outlet, but by providing this air outlet 44 inside the loop type air flow drying tube 5, the particles are in an aggregated state and are dispersed and close to a single particle. Things are classified by the Coanda effect, and only those in a state close to a single particle can be separated from the air current by the cyclone 7 and taken out from the system through the take-out port 8.
The type of the drying tube of the air dryer having the above-described configuration is not limited to the loop-type air drying tube 5 described above. Various shapes of drying tubes can be used, such as those with enlarged barrels or types that impart eddy current motion to the particles to prevent particles from accumulating on the bottom of the horizontal tube. In the method for producing the toner of the present invention, it is most preferable to use an air dryer having a loop type drying tube as shown in FIG.
[0023]
However, even when a dryer of the above-described type is used, using a material to be dried having a significant humidity that deviates from the moisture content range specified in the present invention described above, for example, When drying is performed with the loop type dryer described above, the entire inside of the tube is uniformly filled with water vapor, and as a result, the temperature of the hot airflow decreases to the wet bulb temperature, and conversely, the toner in the drying tube 5 The temperature of the particles can only rise to the wet bulb temperature. In such a state of drying, it is sufficient to remove moisture in the toner particles, but sufficient heat cannot be applied to the toner itself. For this reason, even if an efficient dryer having the above-described configuration is used, the amount of the unreacted polymerizable monomer that is considered to remain mainly in the toner is reduced by drying. It is difficult.
[0024]
Further, in the drying of the object to be dried (colored polymer particles) deviating from the range of the moisture content, even if the length of the drying pipe 5 of the loop dryer is extended in order to extend the residence time, the entire inside of the pipe Is uniformly filled with water vapor, the temperature of the hot airflow is lowered to the wet bulb temperature, and conversely, the toner particles in the drying tube 5 are raised only to the wet bulb temperature. .
[0025]
On the other hand, when the colored polymer particles are in a relatively dry state within the range of the moisture content described above, for example, when the drying is performed with the loop dryer described above, Since the amount of water to be evaporated is relatively small, the temperature of the hot air does not drop so much and it is instantaneous heating, but the hot air mainly acts as sensible heat to sufficiently heat the particles, so the particles themselves (inside) And the internal heat is quickly transferred to the latent heat of the unreacted polymerizable monomer which is supposed to be mainly present inside the particles, so that it can be efficiently vaporized. As a result, the content of the unreacted polymerizable monomer in the toner can be remarkably reduced instantaneously.
Furthermore, when drying the colored polymer particles within the above moisture content range, the length of the drying tube 5 of the loop dryer as shown in FIG. 1 is extended in order to extend the residence time. However, as described above, since the hot air mainly works as sensible heat, the time for heating the colored polymer particles themselves to be dried is increased by the amount of the residence time. For this reason, the amount of the unreacted polymerizable monomer in the obtained toner can be reduced by an amount corresponding to the extension of the length of the drying tube 5.
[0026]
In the method of drying using the high-speed hot air flow as mentioned above used in the method for producing the toner of the present invention, from the viewpoint of the apparatus, if the drying is performed under the following conditions, it is more efficient. Unreacted polymerizable monomer in the material to be dried can be vaporized. That is, the amount of evaporated water per unit time (A) in consideration of the conditions (specific moisture content) of the material to be dried described above. ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A ₁ / A ₂ ) Is 0.008 or less, preferably 0.005 or less, more preferably 0.003 or less, and more efficiently, the unreacted residue remaining in the toner obtained after drying. It is possible to reduce the amount of the polymerizable monomer.
[0027]
In other words, the above means that the drying is performed in such a direction that the water vapor content in the hot airflow is minimized. In order to perform the drying while satisfying the above conditions, factors that affect the drying efficiency on the apparatus, for example, the temperature of the hot air to be fed, the flow rate of the hot air to be fed, the colored polymer particles (toner to be dried) ) Supply amount (supply speed) and the like must be selected with sufficient consideration so as to satisfy the above drying conditions.
[0028]
In addition, the amount of evaporated water per unit time (A ₁ ) Calculated the weight of water contained in the entire colored polymer particles, which are to be dried per unit time, by using the weight percentage obtained by subtracting the moisture content of the sample after drying from the moisture content of the sample before drying. Is. The weight of hot air (A ₂ ) Is the weight of the whole air sent per unit time using the density of the air with respect to the inlet temperature.
[0029]
Next, when the toner produced in the present invention is used for image formation, a minute latent image dot can be faithfully developed and a high quality image can be formed. It is preferable to configure so as to be obtained. However, if an attempt is made to obtain a toner having a very small particle diameter, it may be difficult to dry in a good state. Specifically, it is most preferable that the weight average diameter measured by a Coulter counter is manufactured so as to be in the range of 3 μm to 10 μm. That is, in the case of producing a toner having an extremely small particle diameter with a weight average diameter of less than 3 μm, the cohesive force becomes too strong, so that the number of particles that do not disperse even in a high-speed hot air flow increases, and not only the drying efficiency decreases. In some cases, the amount of the unreacted polymerizable monomer cannot be reduced uniformly. In addition, when such toner with an extremely small particle diameter is used for image formation, a large amount of transfer residual toner is generated on the photosensitive member or intermediate transfer member due to poor transfer efficiency, and an image based on fog and transfer failure is generated. This is not preferable from this point. On the other hand, a toner having a weight average diameter exceeding 10 μm is not preferable because it is likely to be fused to a member when used for image formation, and as a result, image characteristics are deteriorated.
[0030]
In the method for producing a toner of the present invention, a polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce wet colored polymer particles. The toner is obtained by drying under the specific conditions as described above. Hereinafter, the raw material of the toner used in this case will be described.
Examples of the polymerizable monomer that can be used in the production of the polymerized toner include styrene monomers such as styrene, o (m-, p-)-methylstyrene, m (p-)-ethylstyrene; Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylic (Meth) acrylate monomers such as behenyl acid, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; butadiene, isoprene, cyclohexene, (meth) Examples thereof include vinyl monomers such as acrylonitrile and acrylamide, and these are preferably used. Moreover, it may be used in combination of two or more as required. These have a theoretical glass transition temperature (Tg) described in the publication Polymer Handbook 2nd edition III-P139-192 (manufactured by John Wiley & Sons) alone or in general when a polymer is formed. The monomers listed above are appropriately mixed and used so as to indicate 40 to 75 ° C. That is, when a polymer having a theoretical glass transition temperature of less than 40 ° C. is used as the binder resin for the toner, problems arise in terms of storage stability of the toner and durability of the developer. When the transition temperature exceeds 75 ° C., the fixing point is increased. In particular, in the case of a full color toner, the color toners are apt to be insufficiently mixed, the color reproducibility is poor, and the transparency of the OHP image is further improved. This is not preferable from the standpoint of significantly reducing the image quality and enabling high-quality image formation.
[0031]
In the method for producing a toner of the present invention, an outer shell resin is added to the polymerizable monomer composition in order to encapsulate a low softening point substance in the obtained toner and obtain a toner having excellent low-temperature fixability. In addition to the polymerizable monomer to be formed, it is particularly preferable to add a polar resin. Examples of the polar resin used at this time include a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin. As these polar resins, it is particularly preferable to use those which do not contain an unsaturated group capable of reacting with the outer shell resin or the polymerizable monomer in the molecule. In the case of containing a polar resin having an unsaturated group, a crosslinking reaction occurs with the polymerizable monomer forming the outer shell resin layer. Particularly, as a full-color toner, the toner has a very high molecular weight. Since it is disadvantageous for color mixing, it is not preferable.
In the present invention, a so-called sheet polymerization method in which a polymerizable monomer is further adsorbed on the obtained polymer particles and then polymerized using a polymerization initiator can be suitably used.
[0032]
The colorant used as a toner forming material in the present invention will be described. As the black colorant, for example, carbon black, a magnetic material, and a color toned to black using a yellow / magenta / cyan colorant shown below can be used.
As the yellow colorant, for example, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds can be used. Specifically, for example, C.I. I. Pigment yellow, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, etc., and these are preferably used.
[0033]
As the magenta colorant, for example, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds can be used. Specifically, for example, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48; 2, 48; 3, 48; 4, 57; 1, 81; 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254, and these are preferably used.
[0034]
As the cyan colorant, for example, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, a basic dye lake compound, and the like can be used. Specifically, for example, C.I. I. Pigment blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like, and these are preferably used.
[0035]
These colorants can be used singly or as a mixture of a plurality of them and further in a solid solution state. In the toner production method of the present invention, a colorant may be appropriately selected and used from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, dispersibility in the toner, and the like. . What is necessary is just to add and use the addition amount of these coloring agents in the ratio of 1-20 weight part with respect to 100 weight part of resin. When a magnetic material is used as the black colorant, it is preferable to add 40 to 150 parts by weight with respect to 100 parts by weight of the resin, unlike other colorants.
[0036]
In the toner production method of the present invention, a charge control agent may be included in the polymerizable monomer composition in order to improve the charging characteristics of the obtained toner. As the charge control agent used at this time, a known one can be used, but it is preferable to use a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount. In particular, in the present invention, it is particularly preferable to use a charge control agent that has no polymerization inhibitory property and does not have a solubilized product in an aqueous dispersion medium. Specific examples of the negative compounds include salicylic acid, naphthoic acid, dicarboxylic acid metal compounds, sulfonic acids, polymer compounds having carboxylic acid in the side chain, boron compounds, urea compounds, silicon Examples thereof include compounds and calixarene. Examples of positive compounds include quaternary ammonium salts, polymer compounds having quaternary ammonium salts in the side chain, guanidine compounds, and imidazole compounds. The addition amount of these charge control agents is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin. However, in the present invention, the addition of the charge control agent as described above is not essential. That is, in the case of a toner used for a two-component developer, the toner is charged using frictional charging with a carrier. In the case of a toner used for a non-magnetic one-component blade coating development method, a blade member or a sleeve member is used. Since the toner is charged by positively using the frictional charging with the toner, it is not always necessary to include a charge control agent in the toner.
[0037]
Examples of the polymerization initiator that can be used in the present invention include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, and 1,1′-azobis (cyclohexane). -1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and other azo or diazo polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl Examples thereof include peroxide polymerization initiators such as peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide. The amount of these polymerization initiators to be added varies depending on the desired degree of polymerization, but is generally added in the range of 0.5 to 20% by weight with respect to the polymerizable monomer. The kind of the polymerization initiator varies slightly depending on the polymerization method, but may be used alone or in combination with reference to the 10-hour half-life temperature.
In order to control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like can be further added and used.
[0038]
In the method for producing a toner of the present invention, when a suspension polymerization using a dispersant is used as the polymerization method, inorganic compounds and organic compounds as listed below can be used as the dispersant. Specifically, for example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, sulfuric acid Examples include inorganic compounds such as barium, bentonite, silica, and alumina, and organic compounds such as polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and salts thereof, and starch. . These can be used by being dispersed in an aqueous phase. These dispersants are preferably used in the range of 0.2 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer.
[0039]
Among these dispersants, when an inorganic compound is used, a commercially available one may be used as it is, but in order to obtain fine particles, the target inorganic compound is generated and used in a dispersion medium. May be. For example, when tricalcium phosphate is used as a dispersant, it is preferable to use tricalcium phosphate obtained by mixing and reacting an aqueous sodium phosphate solution and an aqueous calcium chloride solution with high stirring.
Further, 0.001 to 0.1 parts by weight of a surfactant may be used for fine dispersion of these dispersants. This is for accelerating the intended action of the dispersant, and specific examples thereof include, for example, sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, lauryl Examples include sodium acid, potassium stearate, calcium oleate and the like.
[0040]
In the toner manufacturing method of the present invention, the toner can be specifically manufactured by the following manufacturing method.
That is, a release agent composed of a low softening point substance, a colorant, a charge control agent, a polymerization initiator, and other additives are added to the polymerizable monomer, and it is uniformly dissolved by a homogenizer or an ultrasonic disperser. The polymerizable monomer composition obtained by dispersing is dispersed in an aqueous phase (aqueous medium) containing a dispersant by a normal stirrer, or a CLEARMIX, homomixer, homogenizer, or the like. Preferably, at this time, the droplets of the polymerizable monomer composition are granulated by adjusting the stirring speed and time so that the droplets have a desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersant. The polymerization temperature is preferably set to 40 ° C. or higher, and generally 50 to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and further, in order to remove unreacted polymerizable monomers and by-products that cause odor at the time of toner fixing, the latter half of the reaction or the reaction. A part of the aqueous medium may be distilled off after completion. After completion of the reaction, the produced toner particles are recovered by washing and filtration, and dried by the drying method as described above. In the suspension polymerization method, it is usually preferable to use 300 to 3,000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the polymerizable monomer composition.
[0041]
Next, various measurement methods used in the present invention will be described.
(1) Measurement of water content of colored polymer particles (toner particles)
The water content was measured using a MA40 electronic moisture meter (manufactured by Sartorius) by the heat loss method at 105 ° C.
(2) Measurement of residual amount of polymerizable monomer and organic solvent remaining in toner particles
The remaining amount of the polymerizable monomer and the organic solvent remaining in the toner particles was determined by using 0.3 g of toner dissolved in 10 g of acetone, applying it to an ultrasonic shaker for 30 minutes, and then allowing to stand for 1 day. Next, the sample for measurement was prepared by filtering through a 0.5 μm filter. Then, the sample was measured by an absolute calibration curve method under the following conditions by gas chromatography.
(GC measurement conditions)
・ Measuring device: HEWLETT PACKARD HP 6890 series
-Capillary column: 30m x 250m, DBWAX film thickness: 0.25m
・ Detector: FID He flow rate = 10 ml / min
・ Injection temperature: 200 ℃
・ Detector temperature: 200 ℃
-Column temperature: temperature raised from 50 ° C to 5 ° C / min for 30 minutes
・ Injected sample volume: 4 μl
[0042]
(3) Measurement of toner particle size distribution
The particle size distribution of the toner can be measured by various methods. In the present invention, the particle size distribution was measured by the following method using a Coulter counter.
As a measuring device, using a Coulter counter TA-II type (manufactured by Coulter Inc.), connecting an interface (manufactured by Nikka) and a CX-1 personal computer (manufactured by Canon) that outputs a number average distribution and a weight average distribution, As the electrolyte solution, a 1% NaCl aqueous solution is prepared using first grade sodium chloride.
As a measurement method, a surfactant, preferably alkylbenzene sulfonate, is added in an amount of about 0.1 to 5 ml as a dispersing agent in 100 to 150 ml of the electrolyte aqueous solution, and further 2 to 20 mg of a measurement sample is added. To prepare. The electrolyte solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and then the Coulter Counter TA-II type is used with an aperture of 100 μm as an aperture and 2 to 40 μm on the basis of the number. The particle size distribution of the particles is measured, and various values are obtained therefrom.
[0043]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not necessarily limited by these Examples.
Example 1
To 710 parts by weight of ion-exchanged water, 0.1 mol / liter-Na _Three PO _Four After 450 parts by weight of the aqueous solution was added and heated to 60 ° C., the mixture was stirred at 3,500 revolutions / minute using CLEARMIX (M Technique Co., Ltd.). To this, 1.0 mol / liter-CaCl ₂ Add 68 parts by weight of aqueous solution to make fine Ca _Three (PO _Four ) ₂ An aqueous medium containing was obtained.
[0044]
On the other hand, a dispersoid system was prepared by the following method.
・ 170 parts by weight of styrene monomer
・ 30 parts by weight of n-butyl acrylate
・ C. I. Pigment Red 122 10 parts by weight
・ Saturated polyester 20 parts by weight
・ 3 parts by weight of salicylic acid metal compound
-The following compound (1) (peak temperature 5DS in DSC, Vickers hardness 1.5) 25 parts by weight
[0045]
[Chemical 1]

[0046]
First, among the above prescriptions, C.I. I. Pigment Red 122, salicylic acid metal compound, and 100 parts by weight of styrene monomer were dispersed for 3 hours using an attritor (manufactured by Mitsui Miike Chemical Industries) to obtain a colorant dispersion. Next, all the rest of the above formulation was added to the resulting colorant dispersion, heated to 60 ° C. and dissolved and mixed for 30 minutes. In this, 10 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was dissolved to prepare a polymerizable monomer composition. Next, the obtained polymerizable monomer composition was put into the previously prepared aqueous dispersion medium and granulated for 15 minutes while maintaining the rotation speed. Then, the stirrer was changed from the high-speed stirrer to the propeller stirring blade, the internal temperature was raised to 80 ° C., and the polymerization was continued at 50 rpm for 10 hours. Next, under conditions of an internal temperature of 80 ° C. and an internal pressure of 47.3 kPs, 4 hr. Distillation was performed. After completion of distillation, the slurry is cooled, diluted hydrochloric acid is added, and Ca _Three (PO _Four ) ₂ Then, filtration, washing with water and crushing were carried out to obtain wet colored polymer particles having a water content of 15%.
At this time, the amount of the polymerizable monomer remaining in the wet colored polymer particles was measured and found to be 420 ppm.
[0047]
The wet colored polymer particles having a water content of 15% obtained above were subjected to preliminary drying using a continuous instantaneous air flow dryer (flash dryer FJD-4: manufactured by Seishin Enterprise Co., Ltd., pipe length: 2 m). . As drying conditions at this time, air at 60 ° C. was 420 m. ^Three The wet colored polymer particles were continuously fed at 70 kg / hr. When the water content of the colored polymer particles obtained after the completion of this preliminary drying was measured, the water content was 4.3%. At this time, the amount of the polymerizable monomer remaining in the colored polymer particles (toner) was measured and found to be 410 ppm, and the weight average particle size was 7.9 μm.
[0048]
Next, the colored polymer particles preliminarily dried as described above were dried as the materials to be dried by the following method. As the drying apparatus, the drying apparatus shown in FIG. 1 having a loop-shaped drying pipe having a pipe length of 2 m was used. As drying conditions, air at 80 ° C. is 420 m. ^Three The colored polymer particles, which are to be dried, were continuously supplied at 62 kg / hr. When the moisture content was measured at the end of drying, the moisture content was 0.3%. That is, the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A ₁ / A ₂ ) Is continuously supplied under the condition of 0.0061. The amount of polymerizable monomer remaining in the colored polymer particles after drying was 180 ppm.
[0049]
Furthermore, the specific surface area by the BET method is 200 m with respect to 100 parts by weight of the toner (colored polymer particles) obtained above. ² A developer was prepared by externally adding 1.5 parts by weight of hydrophobic silica having a / g content.
When this developer was used and a color laser jet printer manufactured by Canon, a color laser shot-2030, was used to perform an image print test in an environment of 23 ° C./65% RH. However, there was no change in the image density between the initial stage and the endurance, and a high-quality image with no voids was obtained. In addition, problems such as toner fusion and memory ghosting to a photoconductor which is an organic semiconductor did not occur. Further, double-sided images were formed, but no occurrence of offset was observed on the front and back surfaces of the transfer material. Further, when an image was formed on an OHP sheet, an image with good transparency was obtained.
Further, when a similar image printing test was performed in an environment of 30 ° C./80% RH, similar good results were obtained.
[0050]
Example 2
Until preliminary drying, colored polymer particles having a water content of 4.3% were obtained in the same manner as in Example 1, which was used as a material to be dried, and had a loop-shaped pipe length of 8 m. Drying was performed using a drying apparatus having the configuration shown in FIG. The drying conditions were the same as in Example 1. As a result, the water content of the obtained colored polymer particles (toner) was 0.1%. Further, the amount of the remaining polymerizable monomer was measured and found to be 60 ppm.
A developer was prepared in the same manner as in Example 1 using the toner (colored polymer particles) obtained above. When this developer was used to evaluate image output in the same manner as in Example 1, good image output results were obtained as in Example 1.
[0051]
Example 3
Until disintegration, the wet colored polymer particles having a water content of 15% obtained in the same manner as in Example 1 were subjected to a continuous instantaneous air flow dryer (flash dryer FJD-4: having a drying pipe with a loop-shaped pipe length of 2 m: Pre-drying was performed using Seishin Enterprise Co., Ltd. As drying conditions at this time, air at 60 ° C. was 420 m. ^Three The wet colored polymer particles were continuously fed at 50 kg / hr. The water content of the preliminarily dried colored polymer particles was measured and found to be 2.8%. At this time, the amount of the polymerizable monomer remaining in the colored polymer particles was measured and found to be 400 ppm, and the weight average particle size was 7.7 μm.
Next, the pre-dried colored polymer particles were taken out to be dried, and dried under the same drying conditions using the same drying apparatus as in Example 1. The moisture content after drying was 0.2%. The amount of the polymerizable monomer remaining in the colored polymer particles was 150 ppm.
A developer was prepared in the same manner as in Example 1 using the toner (colored polymer particles) thus obtained. When this developer was used for image output evaluation similar to Example 1, good image output results were obtained as in Example 1.
[0052]
Example 4
Until the crushing, using a wet colored polymer particle having a water content of 15% obtained in the same manner as in Example 1, a continuous instantaneous air flow dryer (flash dryer FJD-4 having a drying pipe with a loop-shaped pipe length of 2 m is used. : Made by Seishin Enterprise Co., Ltd.). As drying conditions, air at 60 ° C is 420 m. ^Three The colored polymer particles were continuously fed at 25 kg / hr. The water content at the time when the preliminary drying was completed was 0.6%. The amount of the polymerizable monomer remaining in the preliminarily dried colored polymer particles was 395 ppm. The weight average particle size was 7.2 μm.
Next, the colored polymer particles preliminarily dried as described above were used as the materials to be dried, and drying was performed under the same conditions using the same drying apparatus as used in Example 1. Coloring after drying The water content of the polymer particles was 0.2%, and the amount of the polymerizable monomer remaining in the colored polymer particles was 100 ppm.
Using these colored polymer particles (toner), a developer was prepared in the same manner as in Example 1. Then, when the same image output evaluation as in Example 1 was performed using this developer, the same excellent image output result as in Example 1 was obtained.
[0053]
Example 5
Until the preliminary drying, the colored polymer particles having a water content of 4.3% obtained in the same manner as in Example 1 were dried using the same drying apparatus as in Example 1. As drying conditions, air at 80 ° C is 420 m. ^Three The colored polymer particles were continuously fed at 44 kg / hr. At the end of drying, the water content was 0.2%. That is, in this example, as shown in Table 1, the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A ₁ / A ₂ ) Is continuously supplied under the condition of 0.0044. The amount of the polymerizable monomer remaining in the colored polymer particles was 155 ppm.
Using this toner (colored polymer particles), a developer was prepared in the same manner as in Example 1. Then, when the same image output evaluation as in Example 1 was performed using this developer, the same excellent image output result as in Example 1 was obtained.
[0054]
Example 6
Until the preliminary drying, the colored polymer particles having a water content of 4.3% obtained in the same manner as in Example 1 were dried using the same drying apparatus as in Example 1. As drying conditions at that time, air at 80 ° C. is 420 m. ^Three The colored polymer particles were continuously supplied at 29 kg / hr. The moisture content at the time after completion of drying was 0.2%. That is, in this example, as shown in Table 1, the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A ₁ / A ₂ ) Is continuously supplied under the condition of 0.0029. The amount of polymerizable monomer remaining in the colored polymer particles was 130 ppm.
Using this toner (colored polymer particles), a developer was prepared in the same manner as in Example 1. When this developer was used to evaluate image output in the same manner as in Example 1, good image output results were obtained as in Example 1.
[0055]
Comparative Example 1
Until disintegration, the wet colored polymer particles having a water content of 15% obtained in the same manner as in Example 1 were dried for 3 days under the condition of a set temperature of 40 ° C. using a shelf-type hot air dryer. It was. The water content of the colored polymer particles (toner) obtained after drying was 0.2%, and the amount of the polymerizable monomer contained was 50 ppm. Occurrence was seen.
Using the obtained toner (colored polymer particles), a developer was prepared in the same manner as in Example 1. Using this developer, the same image output test as in Example 1 was performed. As a result, solid white spots due to poor transfer occurred from about 500 sheets, and the image density decreased from about 2,000 sheets. It was. Furthermore, image defects due to toner fusion to the photoreceptor occurred at about 2,000 sheets in an environment of 30 ° C./80% RH.
[0056]
Comparative Example 2
Until disintegration, about 40 kg of wet colored polymer particles having a water content of 15% obtained in the same manner as in Example 1 were dried using a fluidized bed dryer (FBS-5 type: manufactured by Okawara Seisakusho). . As drying conditions, air at 50 ° C. was blown at a linear velocity of 0.4 m / second, and after 4 hours, the colored polymer particles were taken out and the water content was measured. As a result, it was 0.1%. At this time, the content of the polymerizable monomer remaining in the colored polymer particles was 80 ppm. However, generation of lumps due to aggregation of colored polymer particles was observed.
An adhesion layer of colored polymer particles was observed on the inner wall of the dryer. The adhesion layer was taken out and the water content was measured and found to be 0.1%, but the content of the polymerizable monomer remaining in the colored polymer particles was 330 ppm, and the remaining amount was large. I understood it.
Using the obtained toner (colored polymer particles), a developer was prepared in the same manner as in Example 1. Using this developer, an image output test similar to that in Example 1 was performed. As a result, solid white spots due to poor transfer occurred from about 1,500 sheets, and under an environment of 30 ° C./80% RH 4, In about 000 sheets, image defects were caused by toner fusion to the photoreceptor.
[0057]
Comparative Example 3
The wet colored polymer having a water content of 15% obtained in the same manner as in Example 1 until crushing is shown in FIG. 1 having a drying pipe having a loop-shaped pipe length of 2 m without performing preliminary drying. Drying was performed using a drying apparatus. In addition, as drying conditions at this time, as in Example 1, air at 80 ° C. was 420 m. ^Three The colored polymer particles were continuously fed at 62 kg / hr. The moisture content at this point is 1.8%. Therefore, in this comparative example, the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A ₁ / A ₂ ) Is 0.02, and the material to be dried is continuously supplied. Further, it was found that the amount of the polymerizable monomer remaining in the colored polymer particles was 410 ppm, and it remained almost even after drying.
A developer was prepared from the obtained toner (colored polymer particles) in the same manner as in Example 1. Using this developer, the same image output test as in Example 1 was performed. As a result, solid white spots due to poor transfer occurred from about 1,000 sheets, and the image density decreased from about 3,500 sheets. It was seen. Further, an image defect occurred due to toner fusion to the photoreceptor on about 3,000 sheets in an environment of 30 ° C./80% RH.
[0058]
Comparative Example 4
Until the crushing, the wet colored polymer particles having a water content of 15% obtained in the same manner as in Example 1 were subjected to a loop-shaped pipe length of 8 m as in Example 2 without performing preliminary drying. Drying was performed using the drying apparatus shown in FIG. 1 having a drying tube. The drying conditions were the same as in Example 1 except that air at 80 ° C. was 420 m. ^Three The colored polymer particles were continuously fed at 62 kg / hr. When the moisture content was measured at the end of drying, the moisture content was 0.6%. Therefore, in this comparative example, the amount of evaporated water per unit time (A ₁ ) And the weight of hot air sent per unit time (A ₂ ) Ratio (A ₁ / A ₂ ) Is 0.022, and it is supplied continuously. Further, it was found that the amount of the polymerizable monomer remaining in the colored polymer particles after drying was 400 ppm, and it remained almost even after drying.
A developer was prepared from the obtained toner (colored polymer particles) in the same manner as in Example 1. Using this developer, an image output test similar to that in Example 1 was performed. As a result, solid white spots due to poor transfer occurred from about 1,000 sheets, and the image density decreased from about 2,000 sheets. Further, image defects due to toner fusion to the photosensitive member occurred in about 2,500 sheets under an environment of 30 ° C./80% RH.
[0059]
The following table 1 summarizes the drying conditions and results obtained in Examples and Comparative Examples.
[Table 1]

[0060]
[Table 2]

[0061]
【The invention's effect】
As described above, according to the present invention, when the wet toner particles obtained by the polymerization method are dried, the unreacted polymerizable monomer can be uniformly removed, and the heat is received for a long time. There is provided a toner manufacturing method capable of realizing efficient drying. As a result, a toner capable of forming a high-quality image without causing image defects due to the remaining unreacted polymerizable monomer is obtained.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an example of a system of an apparatus for drying a material to be dried used in the present invention in a hot air stream while dispersing it in a granular form and sending it in parallel with a high-speed air stream.
[Explanation of symbols]
1. Blower
2. Hot air generator
3. Airflow dispersion part
4). Air outlet
5). Airflow drying tube
6). Equipment to be dried
7). Cyclone
8). Dry product outlet
9. Bag filter

Claims (7)

A method for producing a toner, wherein the residual amount of unreacted polymerizable monomer present in the toner particles is 200 ppm or less, comprising at least a polymerizable monomer and a colorant. Is then polymerized in an aqueous dispersion medium to form wet colored polymer particles, and then the water content of the particles is adjusted to obtain colored polymer particles having a water content of 5.0% or less. have a tube, and formed by the air flow withdrawal outlet is provided inside of the drying, but using a flash dryer of the structure in which the drying tube with the dried particles are discharged are classified, obtained colored heavy A method for producing a toner, wherein the coalesced particles are dispersed while being continuously fed into a high-speed hot air stream, and dried while being sent in parallel with the hot air stream to obtain toner particles constituting the toner.   The method for producing a toner according to claim 1, wherein when the moisture content of the wet colored polymer particles is adjusted, colored polymer particles having a water content of 3.0% or less are obtained.   The method for producing a toner according to claim 1, wherein when the moisture content of the wet colored polymer particles is adjusted, colored polymer particles having a water content of 1.0% or less are obtained. The ratio of the amount of evaporated water per unit time (A ₁ ) to the weight of the hot air sent per unit time (A ₂ ) (A ₁ / A) is used to dry the colored polymer particles in a high-speed hot air stream. _The method for producing a toner according to any one of claims 1 to 3, which is carried out under a condition that ₂ ) is 0.008 or less. The ratio of the amount of evaporated water per unit time (A ₁ ) to the weight of the hot air sent per unit time (A ₂ ) (A ₁ / A) is used to dry the colored polymer particles in a high-speed hot air stream. _The method for producing a toner according to any one of claims 1 to 3, which is performed under a condition in which ₂ ) is 0.005 or less. The ratio of the amount of evaporated water per unit time (A ₁ ) to the weight of the hot air sent per unit time (A ₂ ) (A ₁ / A) is used to dry the colored polymer particles in a high-speed hot air stream. _The method for producing a toner according to any one of claims 1 to 3, which is performed under a condition in which ₂ ) is 0.003 or less.   The method for producing a toner according to claim 1, wherein the weight average particle diameter of the colored polymer particles before drying in a hot air stream is 3 μm to 10 μm.

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