JP3748498B2 - Toner production method - Google Patents

Description

【００５８】
本発明のトナーの製造方法としては、特公昭３６−１０２３１号公報、特開昭５９−５３８５６号公報、特開昭５９−６１８４２号公報に述べられている懸濁重合方法を用いることが可能である。
【００５９】
本発明においては、一旦得られた重合粒子に更に単量体を吸着せしめた後、重合開始剤を用い重合せしめる所謂シード重合方法も本発明に好適に利用することができる。
【００６０】
また、本発明においては、定着性の観点から多量の低軟化点物質をトナー粒子に含有せしめる必要性から、必然的に低軟化点物質を外殻樹脂中に内包化せしめる必要がある。低軟化点物質を内包化せしめる具体的方法としては、水系媒体中での材料の極性を主要単量体より低軟化点物質の方を小さく設定し、更に少量の極性の大きな樹脂又は単量体を添加せしめることで低軟化点物質を外殻樹脂で被覆した所謂コア−シェル構造を有するトナー粒子を得ることができる。トナー粒子の粒度分布制御や粒径の制御は、難水溶性の無機塩や保護コロイド作用をする分散剤の種類や添加量を変える方法や機械的装置条件、例えばローターの周速，パス回数，撹拌羽根形状等の撹拌条件や容器形状又は、水溶液中での固形分濃度等を制御することにより行うことができる。
【００６１】
トナー粒子がコア−シェル構造を有しているということは、トナー粒子の断層面を観察することにより確認できるが、トナー粒子の断層面の観察は具体的には以下の様にして行われる。常温硬化性のエポキシ樹脂中にトナーを十分分散させた後温度４０℃の雰囲気中で２日間硬化させ得られた硬化物を四三酸化ルテニウム、必要により四三酸化オスミウムを併用し染色を施した後、ダイヤモンド歯を備えたミクロトームを用い薄片状のサンプルを切り出し透過電子顕微鏡（ＴＥＭ）を用いトナー粒子の断層形態を測定した。本発明においては、用いる低軟化点物質と外殻を構成する樹脂との若干の結晶化度の違いを利用して材料間のコントラストを付けるため四三酸化ルテニウム染色法を用いることが好ましい。代表的な一例を図５に示す。後述する実施例において製造されたトナーは、低軟化点物質が外殻樹脂で内包化されている構造を有していることが観測された。
【００６２】
上記重合トナーに使用できる重合性単量体としては、スチレン，ｏ（ｍ−，ｐ−）−メチルスチレン，ｍ（ｐ−）−エチルスチレンの如きスチレン系単量体；（メタ）アクリル酸メチル，（メタ）アクリル酸エチル，（メタ）アクリル酸プロピル，（メタ）アクリル酸ブチル，（メタ）アクリル酸オクチル，（メタ）アクリル酸ドデシル，（メタ）アクリル酸ステアリル，（メタ）アクリル酸ベヘニル，（メタ）アクリル酸２−エチルヘキシル，（メタ）アクリル酸ジメチルアミノエチル，（メタ）アクリル酸ジエチルアミノエチルの如き（メタ）アクリル酸エステル系単量体；ブタジエン，イソプレン，シクロヘキセン，（メタ）アクリロニトリル，アクリル酸アミドの如きビニル系単量体が好ましく用いられる。これらは、単独または一般的には出版物ポリマーハンドブック第２版ＩＩＩ−ｐ１３９〜１９２（Ｊｏｈｎ Ｗｉｌｅｙ＆Ｓｏｎｓ社製）に記載の理論ガラス温度（Ｔｇ）が、４０〜７５℃を示すように単量体を適宜混合し用いられる。理論ガラス転移温度が４０℃未満の場合には、トナーの保存安定性や現像剤の耐久安定性の面から問題が生じ、一方７５℃を超える場合は定着点の上昇をもたらし、特にフルカラートナーの場合においては各色トナーの混色が不十分となり色再現性に乏しく、更にＯＨＰ画像の透明性を著しく低下させ高画質の面から好ましくない。
【００６３】
本発明においては、外殻樹脂中に低軟化点物質を内包化せしめるため外殻樹脂の他に更に極性樹脂を添加せしめることが特に好ましい。本発明に用いられる極性樹脂としては、スチレンと（メタ）アクリル酸の共重合体，マレイン酸共重合体，飽和ポリエステル樹脂，エポキシ樹脂が好ましく用いられる。該極性樹脂は、外殻樹脂又は単量体と反応しうる不飽和基を分子中に含まないものが特に好ましい。不飽和基を有する極性樹脂を用いた場合においては、外殻樹脂層を形成する単量体と極性樹脂の間において架橋反応が起きフルカラー用トナーとしては、極めて高分子量になり四色トナーの混色性が不利となるため好ましくない。
【００６４】
本発明において用いられる低軟化点物質としては、ＡＳＴＭ Ｄ３４１８−８に準拠し測定された主体極大ピーク値が、４０〜９０℃を示す化合物が好ましい。極大ピークが４０℃未満であると低軟化点物質の自己凝集力が弱くなり、結果として耐高温オフセット性が弱くなりフルカラートナーには好ましくない。一方極大ピークが、９０℃を超えると定着温度が高くなり、定着画像表面を適度に平滑化せしめることが困難となり混色性の点から好ましくない。更に直接重合方法によりトナーを得る場合においては、水系で造粒，重合を行うため極大ピーク値の温度が高いと、主に造粒中に低軟化点物質が析出してきて懸濁系を阻害するため好ましくない。
【００６５】
上記の極大ピーク値の温度の測定には、例えばパーキンエルマー社製ＤＳＣ−７を用いる。装置検出部の温度補正はインジウムと亜鉛の融点を用い、熱量の補正についてはインジウムの融解熱を用いる。サンプルは、アルミニウム製パンを用い対照用に空パンをセットし、昇温速度１０℃／分で測定を行う。
【００６６】
具体的にはパラフィンワックス，ポリオレフィンワックス，フィッシャートロピッシュワックス，アミドワックス，高級脂肪酸，エステルワックス及びこれらの誘導体又はこれらのグラフト／ブロック化合物が利用できる。下記一般構造式で示す炭素数が１０以上の長鎖エステル部分を１個以上有するエステルワックスが、ＯＨＰの透明性を阻害せずに高温オフセット性に効果を有するので本発明においては特に好ましい。本発明に好ましい具体的なエステルワックスの代表的化合物の構造式を以下に一般構造式▲１▼，一般構造式▲２▼及び一般構造式▲３▼として示す。
【００６７】
【外２】

（式中、ａ及びｂは０〜４の整数を示し、ａ＋ｂは４であり、Ｒ₁及びＲ₂は炭素数が１〜４０の有機基を示し、且つＲ₁とＲ₂との炭素数の差が１０以上である。ｎ及びｍは０〜１５の整数を示し、ｎとｍが同時に０になることはない。）
【００６８】
【外３】

（式中、ａ及びｂは０〜４の整数を示し、ａ＋ｂは４であり、Ｒ₁は炭素数が１０〜４０の有機基を示し、ｎ及びｍは０〜１５の整数を示し、ｎとｍが同時に０になることはない。）
【００６９】
【外４】

（式中、ａ及びｂは０〜３の整数を示し、ａ＋ｂは３以下であり、Ｒ₁及びＲ₂は炭素数が１〜４０の有機基を示し、且つＲ₁とＲ₂との炭素数の差が１０以上である。Ｒ₃は炭素数が１以上の有機基を示し、ｎ及びｍは０〜１５の整数を示し、ｎとｍが同時に０になることはない。）
【００７０】
本発明で好ましく用いられるエステルワックスは、硬度０．５〜５．０を有するものが好ましい。エステルワックスの硬度は、直径２０ｍｍφで厚さが５ｍｍの円筒形状のサンプルを作製した後、例えば島津製作所製ダイナミック超微小硬度計（ＤＵＨ−２００）を用いビッカース硬度を測定した値である。測定条件は、０．５ｇの荷重で負荷速度が９．６７ｍｍ／秒の条件で１０μｍ変位させた後１５秒間保持し、得られた打痕形状を測定しビッカース硬度を求める。エステルワックスの硬度が０．５未満では定着器の圧力依存性及びプロセススピード依存性が大きくなり、耐高温オフセット効果の発現が不十分となりやすく、他方硬度が５．０を超える場合ではトナーの保存安定性に乏しく、ワックス自身の自己凝集力も小さいため同様に耐高温オフセットが不十分となりやすい。具体的化合物としては、下記化合物が挙げられる。
【００７１】
【外５】

【００７２】
【外６】

【００７３】
【外７】

【００７４】
【外８】

【００７５】
近年フルカラー両面画像の必要性も増してきており、両面画像を形成せしめる際においては、最初に表面に形成された転写紙上のトナー像が次に裏面に画像を形成する時にも定着器の加熱部を再度通過する可能性があり、よりトナーの耐高温オフセット性を十分に考慮する必要がある。その為にも本発明においては、多量の低軟化点物質の添加が必須となる。具体的には、低軟化点物質をトナー中に５〜４０重量％添加することが好ましい。５重量％未満の添加では十分な耐高温オフセット性を示さず、更に両面画像の定着時において裏面の画像がオフセット現象を示す傾向がある。また４０重量％を超える場合は、造粒時にトナー粒子同士の合一が起きやすく、粒度分布の広いものが生成しやすく、本発明には不適当であった。
【００７６】
本発明に用いられる着色剤は、黒色着色剤としてカーボンブラック，磁性体，以下に示すイエロー／マゼンタ／シアン着色剤を用い黒色に調色されたものが利用できる。
【００７７】
イエロー着色剤としては、縮合アゾ化合物，イソインドリノン化合物，アンスラキノン化合物，アゾ金属錯体，メチン化合物，アリルアミド化合物に代表される化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントイエロー１２、１３、１４、１５、１７、６２、７４、８３、９３、９４、９５、１０９、１１０、１１１、１２８、１２９、１４７、１６８が好適に用いられる。
【００７８】
マゼンタ着色剤としては、縮合アゾ化合物，ジケトピロロピロール化合物，アンスラキノン，キナクリドン化合物，塩基染料レーキ化合物，ナフトール化合物，ベンズイミダゾロン化合物，チオインジゴ化合物，ペリレン化合物が用いられる。具体的には、Ｃ．Ｉ．ピグメントレッド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、２５４が特に好ましい。
【００７９】
シアン着色剤としては、銅フタロシアニン化合物及びその誘導体，アンスラキノン化合物，塩基染料レーキ化合物等が利用できる。具体的には、Ｃ．Ｉ．ピグメントブルー１、７、１５、１５：１、１５：２、１５：３、１５：４、６０、６２、６６が特に好適に利用できる。
【００８０】
これらの着色剤は、単独又は混合し更には固溶体の状態で用いることができる。本発明の着色剤は、色相角，彩度，明度，耐候性，ＯＨＰ透明性，トナー中への分散性の点から選択される。該着色剤の添加量は、樹脂１００重量部に対し１〜２０重量部添加して用いられる。
【００８１】
黒色着色剤として磁性体を用いた場合には、他の着色剤と異なり、樹脂１００重量部に対し４０〜１５０重量部添加して用いられる。
【００８２】
本発明に用いられる荷電制御剤としては、公知のものが利用できるが、無色でトナーの帯電スピードが速く且つ一定の帯電量を安定して維持できる荷電制御剤が好ましい。更に本発明において直接重合方法を用いる場合には、重合阻害性が無く水系への可溶化物の無い荷電制御剤が特に好ましい。具体的化合物としては、ネガ系としてサリチル酸，ナフトエ酸，ダイカルボン酸の金属化合物、スルホン酸，カルボン酸を側鎖に持つ高分子型化合物、ホウ素化合物、尿素化合物、ケイ素化合物、カリークスアレーンが利用できる。ポジ系として四級アンモニウム塩、該四級アンモニウム塩を側鎖に有する高分子型化合物，グアニジン化合物，イミダゾール化合物が好ましく用いられる。該荷電制御剤は樹脂１００重量部に対し０．５〜１０重量部が好ましい。しかしながら、本発明において荷電制御剤の添加は必須ではなく、二成分現像方法を用いた場合においては、キャリアとの摩擦帯電を利用し、非磁性一成分ブレードコーティング現像方法を用いた場合においてもブレード部材やスリーブ部材との摩擦帯電を積極的に利用することもできるため、トナー中に必ずしも荷電制御剤を含む必要はない。
【００８３】
本発明に係る重合トナーに使用できる重合開始剤としては、例えば、２，２’−アゾビス−（２，４−ジメチルバレロニトリル）、２，２’−アゾビスイソブチロニトリル、１，１’−アゾビス（シクロヘキサン−１−カルボニトリル）、２，２’−アゾビス−４−メトキシ−２，４−ジメチルバレロニトリル、アゾビスイソブチロニトリルの如きアゾ系又はジアゾ系重合開始剤；ベンゾイルペルオキシド、メチルエチルケトンペルオキシド、ジイソプロピルペルオキシカーボネート、クメンヒドロペルオキシド、２，４−ジクロロベンゾイルペルオキシド、ラウロイルペルオキシドの如き過酸化物系重合開始剤が用いられる。該重合開始剤の添加量は、目的とする重合度により変化するが一般的には重合性単量体に対し０．５〜２０重量％添加され用いられる。重合開始剤の種類は、重合方法により若干異なるが、１０時間半減期温度を参考に、単独又は混合し利用される。
【００８４】
重合度を制御するため公知の架橋剤，連鎖移動剤，重合禁止剤等を更に添加し用いることも可能である。
【００８５】
本発明に係る重合トナーにおいて、分散剤を用いた懸濁重合を利用する場合用いる分散剤としては、無機化合物として、リン酸三カルシウム，リン酸マグネシウム，リン酸アルミニウム，リン酸亜鉛，炭酸カルシウム，炭酸マグネシウム，水酸化カルシウム，水酸化マグネシウム，水酸化アルミニウム，メタケイ酸カルシウム，硫酸カルシウム，硫酸バリウム，ベントナイト，シリカ，アルミナが挙げられる。有機化合物として、ポリビニルアルコール，ゼラチン，メチルセルロース，メチルヒドロキシプロピルセルロース，エチルセルロース，カルボキシメチルセルロースのナトリウム塩，ポリアクリル酸及びその塩，デンプンを水相に分散させて使用できる。これら分散剤は、重合性単量体１００重量部に対して０．２〜２０重量部を使用することが好ましい。
【００８６】
これら分散剤の中で、無機化合物を用いる場合、市販のものをそのまま用いても良いが、細かい粒子を得るために、分散媒中にて該無機化合物を生成させても良い。例えば、リン酸三カルシウムの場合、高撹拌下において、リン酸ナトリウム水溶液と塩化カルシウム水溶液を混合すると良い。
【００８７】
また、これら分散剤の微細な分散の為に、０．００１〜０．１重量部の界面活性剤を使用してもよい。これは上記分散剤の所期の作用を促進する為のものであり、その具体例としては、ドデシルベンゼン硫酸ナトリウム，テトラデシル硫酸ナトリウム，ペンタデシル硫酸ナトリウム，オクチル硫酸ナトリウム，オレイン酸ナトリウム，ラウリル酸ナトリウム，ステアリン酸カリウム，オレイン酸カルシウムが挙げられる。
【００８８】
本発明のトナー製造方法においては、以下の如き製造方法によって具体的にトナーを製造することが可能である。
【００８９】
即ち、重合性単量体中に低軟化点物質からなる離型剤，着色剤，荷電制御剤，重合開始剤その他の添加剤を加え、ホモジナイザー，超音波分散機等によって均一に溶解又は分散せしめた単量体系を、分散剤を含有する水相中に通常の撹拌機またはホモミキサー，ホモジナイザー等により分散せしめる。好ましくは単量体液滴が所望のトナー粒子のサイズを有するように撹拌速度，時間を調整し、造粒する。その後は分散剤の作用により、粒子状態が維持され、且つ粒子の沈降が防止される程度の撹拌を行えば良い。重合温度は４０℃以上、一般的には５０〜９０℃の温度に設定して重合を行うのが良い。また、重合反応後半に昇温しても良く、更に、トナー定着時の臭いの原因等となる未反応の重合性単量体、副生成物等を除去するために反応後半、又は、反応終了後に一部水系媒体を留去しても良い。反応終了後、生成したトナー粒子を洗浄・濾過により回収し、本発明に係る乾燥方法によって乾燥する。懸濁重合法においては、通常単量体系１００重量部に対して水３００〜３０００重量部を分散媒として使用するのが好ましい。
【００９０】
本発明のトナー粒子の含水率の測定は、１０５℃における加熱減量法によって求めた。
【００９１】
トナー粒子中に残存する重合性単量体の残存量の定量は、トナー０．２ｇをテトラヒドロフラン（ＴＨＦ）４ｍｌに溶解したものを用い、それぞれガスクロマトグラフィーにて以下の条件で内部標準法により測定した。
【００９２】

【００９３】
また、トナーの粒度分布は種々の方法によって測定できるが、本発明においてはコールターカウンターを用いて行った。
【００９４】
測定装置としてはコールターカウンターＴＡ−ＩＩ型（コールター社製）を用い、個数平均分布、体積平均分布を出力するインターフェイス（日科機製）及びＣＸ−１パーソナルコンピューター（キヤノン製）を接続して、電解液は１級塩化ナトリウムを用いて１％ＮａＣｌ水溶液を調製する。
【００９５】
測定法としては前記電解水溶液１００〜１５０ｍｌ中に分散剤として界面活性剤、好ましくはアルキルベンゼンスルホン酸塩を０．１〜５ｍｌ加え、さらに測定試料を２〜２０ｍｇ加える。
【００９６】
試料を懸濁した電解液は超音波分散器で約１〜３分間分散処理を行い、前記コールターカウンターＴＡ−ＩＩ型により、アパチャーとして１００μｍアパチャーを用いて、個数を基準として２〜４０μｍの粒子の粒度分布を測定して、それから各種値を求める。
【００９７】
【実施例】
以下、本発明を実施例によって具体的に説明する。但し、本実施例は本発明を何ら限定するものではない。
【００９８】
＜実施例１＞
イオン交換水７１０重量部に０．１モル／リットル−Ｎａ₃ＰＯ₄水溶液４５０重量部を投入し６０℃に加温した後、クリアミキサー（エム・テクニック社製）を用いて３，５００回転／分にて撹拌した。これに１．０モル／リットル−ＣａＣｌ₂水溶液６８重量部を添加し、Ｃａ₃（ＰＯ₄）₂を含む水系媒体を得た。
【００９９】
一方、分散質系は、
・スチレン単量体 １７０重量部
・ｎ−ブチルアクリレート ３０重量部
・グラフト化カーボンブラック １０重量部
・飽和ポリエステル １０重量部
・サリチル酸金属化合物 ３重量部
・前記化合物（１） ２５重量部
（ＤＳＣにおけるピーク温度５９．４℃，ビッカース硬度１．５）
上記処方のうち、グラフト化カーボンブラック、サリチル酸金属化合物とスチレン単量体１００重量部をアトライター（三井三池化工機製）を用い３時間分散し、着色剤分散液を得た。次に、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。
【０１００】
上記重合性単量体組成物を前記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、高速撹拌機からプロペラ撹拌羽根に撹拌機を変え、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。重合終了後、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、水洗を行い、含水率２２ｗｔ％の湿潤着色重合体粒子を得た。得られた重合体粒子の重合平均粒径は６．２μｍであった。
【０１０１】
得られた湿潤着色重合体粒子約４０ｋｇを解砕後、図６の如き構成を有する流動層乾燥機（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、２時間後にトナー粒子を取り出し含水率を測定したところ、０．３ｗｔ％であった。また、この時点でトナー粒子に残留している重合性単量体の含有量は４５０ｐｐｍであった。トナー粒子の凝集によるダマの発生もなく、目開き１４９μｍの篩いの通過率は９６％であった。ここでいう「通過率」とは以下のようにして求めた。
【０１０２】
【外９】

【０１０３】
次に、取り出した一次乾燥トナー粒子約３０ｋｇを、図２の如き構成を有する容量１００リットルのナウター型の真空乾燥機（ＮＸＶ−１型：ホソカワミクロン社製）を用いて乾燥を行った。乾燥条件として、ジャケット加熱温度５０℃、真空度２〜５ｋＰａで４時間乾操を行った。この時点で含水率は０．１ｗｔ％であり、トナー粒子に残留している重合性単量体の含有量は、５０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は９５％であった。
【０１０４】
得られたトナー粒子の断層写真の模式図を図５に示す。低軟化点物質である化合物（１）が外殻樹脂で覆われた構造を有している。
【０１０５】
得られたトナー粒子中の粗粉を分級により除去し、除去後のトナー粒子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、トナーを得た。
【０１０６】
このトナーを用いて、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の画像が得られた。また、有機半導体である感光体に、トナー融着、メモリーゴーストのような問題を生じなかった。さら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。
【０１０７】
また、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。
【０１０８】
＜実施例２＞
実施例１の流動層乾燥機による乾燥時間を、１．５時間にする以外は同様にして、一次乾操トナー粒子を得た。トナー粒子のの含水率を測定したところ、０．７ｗｔ％であり、粒子中に残存している重合性単量体の量は６１０ｐｐｍであった。また目開き１４９μｍの篩いの通過率は９７％であった。
【０１０９】
次に、得られた一次乾燥トナー粒子約３０ｋｇを、乾燥時間を５時間にする以外は実施例１と同様にして、ナウター型の真空乾燥機（ＮＸＶ−１型：ホソカワミクロン社製）を用いて乾燥し、トナー粒子を製造した。この時点での含水率は０．１ｗｔ％であり、トナー粒子中に残存している重合性単量体の含有量は９０ｐｐｍであった。また目開き１４９μｍの篩いの通過率は９５％であった。
【０１１０】
得られたトナー粒子に対し、実施例１と同様にしてシリカを外添し、トナーを調製した。
【０１１１】
該トナーを用いて実施例１と同様の画出し評価を行ったところ、実施例１と同様に良好な画像が得られた。
【０１１２】
＜実施例３＞
実施例１の流動層乾燥機で２時間乾燥し取り出して得た一次乾燥トナー粒子約２０ｋｇを、図３の如き構成を有する容量５０リットルのリボコーン真空乾燥機（ＲＤ−５０型：大川原製作所社製）に投入し、５０℃，真空度０．７〜２ｋＰａで真空乾燥を行った。４時間後の含水率を測定したところ、０．１ｗｔ％であり、目開き１４９μｍの篩いの通過率は９０％であった。また、トナー粒子に残留している重合性単量体の含有量は、１２０ｐｐｍであった。
【０１１３】
さらに実施例１と同様にしてトナーを調製し、画出し評価を行ったところ、実施例１と同様に良好な画像が得られた。
【０１１４】
＜実施例４＞
まず、実施例１と同じ水系分散媒を用意した。
【０１１５】
一方、分散質系として
・スチレン単量体 １８０重量部
・２−エチルヘキシルアクリレート ２０重量部
・Ｃ．Ｉ．ピグメントブルー１５：３ １０重量部
・飽和ポリエステル １０重量部
・サリチル酸金属化合物 ５重量部
・前記化合物（１） ２５重量部
上記処方のうち、Ｃ．Ｉ．ピグメントブルー１５：３、サリチル酸金属化合物とスチレン単量体１００重量部をアトライター（三井三池化工機社製）を用い３時間分散し、着色剤分散液を得た。次に、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。
【０１１６】
上記重合性単量体組成物を前記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、高速撹拌機からプロペラ撹拌羽根に撹拌機を変え、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。重合終了後、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、水洗を行い、含水率２３ｗｔ％の湿潤着色重合体粒子を得た。得られた重合体粒子の重量平均粒径は６．５μｍであった。
【０１１７】
次に、得た含水率２３％の湿潤着色重合体粒子を、図４にあるような円筒縦長形状の振動流動層乾燥機内に投入し乾燥を行った。
【０１１８】
図４のような乾燥装置は、その全体が円筒形状を有し、気体の流通経路に沿って、気体流入口７２と、気体を整流する目皿板７３、粒子と気体との流動層が形成される乾燥室７４、粒子を捕捉するフィルター７５、排気口７６から構成される。排気口７６は、排気ブロアに接続し排気を行う。
【０１１９】
また、乾燥室底部の架台の相対向する側壁面に２基の振動モータ（バイブレータ）８０が取付けられており、乾燥室全体に振動を与えることができる。振動の振幅は、振動モータの軸の両端に取付けられているアンバランスウエイト間の取付け角度により調整でき、振動数は、インバータにより任意に設定できる。
【０１２０】
乾燥原料は、乾燥室上部の投入口７８より供給され、乾燥品は、乾燥室下部の排出口７９から排出される。
【０１２１】
この乾燥装置を用いる乾燥操作は、たとえば以下のように行われる。すなわち、乾燥室に投入された被乾燥粒子は、振動モータにより与えられた機械的振動と、気体流入口から投入され、目皿板を介して導入された温風により、吹き上げられ、気体とともに流動化する。乾燥室内に浮遊して流動層を形成した被乾燥粒子は、この流動層内部において、気体と均一に混合され乾燥される。
【０１２２】
乾燥室７４の上部（排気口７６側）に吹き上げられた被乾燥粒子は、フィルター７５に捕捉されるが、例えばこのフィルターに逆洗パルスを与えることにより、被乾燥粒子はフィルターから払い落とされて下方に戻される。
【０１２３】
本実施例においては、乾燥条件として、振動数２５Ｈｚ，振幅２．５ｍｍの振動を与え、下部より５０℃の空気を線速度０．２ｍ／秒で吹き込んだ。２時間後にトナーを取り出し含水率を測定したところ、０．３ｗｔ％であった。また、この時点でトナー粒子に残留している重合性単量体の量は、４００ｐｐｍであった。トナー凝集によるダマの発生も少なく、目開き１４９μｍの篩いの通過率は９４％であった。
【０１２４】
次に、取り出した一次乾燥トナー粒子約３０ｋｇを、実施例１と同様にして、ナウター型の真空乾燥機（ＮＸＶ−１型：ホソカワミクロン社製）を用いて乾燥し、トナー粒子を製造した。この時点での含水率は０．１ｗｔ％であり、トナー粒子中に残存している重合性単量体の含有量は４０ｐｐｍであった。また目開き１４９μｍの篩いの通過率は９３％であった。
【０１２５】
さらに実施例１と同様にしてトナー調製し、画出し評価を行ったところ、実施例１と同様に良好な画像が得られた。また、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。
【０１２６】
＜実施例５＞
実施例１における流動層乾燥機による乾燥時間を３時間にする以外は同様にして、一次乾燥トナー粒子を得た。トナー粒子の含水率を測定したところ、０．１ｗｔ％であり、粒子中に残存している重合性単量体の量は３１０ｐｐｍであった。また目開き１４９μｍの篩いの通過率は９２％であった。
【０１２７】
次に、得られた一次乾燥トナー粒子約３０ｋｇを実施例１と同様にして、ナウター型の真空乾燥機を用いて４時間乾燥し、トナー粒子を製造した。この時点での含水率は０．１ｗｔ％であり、トナー粒子中に残存している重合性単量体の含有量は４０ｐｐｍであった。また目開き１４９μｍの篩いの通過率は９１％であった。
【０１２８】
さらに実施例１と同様にしてトナーを調製し、画出し評価を行ったところ、実施例１と同様に良好な画像が得られた。
【０１２９】
＜実施例６＞
実施例１の流動層乾燥機で２時間乾燥し、取り出した一次乾燥トナー粒子約３０ｋｇを、実施例１で用いたナウター型の真空乾燥機を用いて以下の条件で乾燥を行った。ジャケット加熱温度５０℃、真空度２〜５ｋＰａ、下部より窒素ガスを０．５Ｎリットル／ｍｉｎで供給し３時間乾燥を行った。この時点での含水率は０．１ｗｔ％であり、トナー粒子中に残存している重合性単量体の含有量は３０ｐｐｍであった。また目開き１４９μｍの篩いの通過率は９６％であった。
【０１３０】
さらに実施例１と同様にしてトナーを調製し、画出し評価を行ったところ、実施例１と同様に良好な画像が得られた。
【０１３１】
＜比較例１＞
実施例１で得た含水率２２％の湿潤着色重合体粒子約４０ｋｇを解砕後、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時間後にトナーを取り出し含水率を測定したところ、０．１ｗｔ％未満であった。また、トナー粒子に残留している重合性単量体含有量は、１８０ｐｐｍであったが、トナー凝集によるダマの発生があり、目開き１４９μｍの篩いの通過率は８５％であった。また、乾燥機内壁部には、トナーの付着層がみられた。このトナーの付着層を取り出し含水率を測定したところ、０．１ｗｔ％未満であり、付着層中のトナー粒子に残留している重合性単量体の含有量は、３１０ｐｐｍであった。
【０１３２】
得られたトナーに対し実施例１と同様の操作を行いトナーとした。
【０１３３】
同様の画出し試験を行ったところ、耐久１，５００枚程度から転写不良によるベタ部白抜けが発生し、さらに、３０℃／８０％ＲＨの環境下４，５００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。
【０１３４】
＜比較例２＞
実施例１で得た含水率２２ｗｔ％の湿潤着色重合体粒子をアルミパット上に分散し、５０℃，真空度３ｋＰａで真空乾燥を行った。２時間後の含水率を測定したところ、１２ｗｔ％であった。含水率が０．１ｗｔ％以下になるまでにさらに１６時間乾燥を行い、乾燥トナーを得た。得られたトナー粒子は一部凝集しており、目開き１４９μｍの篩いの通過率は７０％であった。また、トナー粒子に残留している重合性単量体含有量は、１８０ｐｐｍであった。
【０１３５】
得られたトナー粒子を解砕し、以下実施例１と同様の操作を行いトナーとした。実施例 １と同様の画出し評価を行ったところ、耐久５００枚程度から転写不良によるベタ部白抜けが発生した。
【０１３６】
＜比較例３＞
実施例１で得た含水率２２ｗｔ％の湿潤着色重合体粒子約３０ｋｇを解砕後、容量１００リットルのナウター型の真空乾燥機（ＮＸＶ−１型：ホソカワミクロン社製）を用いて乾燥を行った。乾燥条件として、ジャケット加熱温度５０℃，真空度２〜５ｋＰａで４時間乾燥を行った。この時点でトナー粒子の含水率を測定したところ０．３％ｗｔであり、トナー粒子に残留している重合性単量体の含有量は、５２０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は７５％であった。
【０１３７】
得られたトナー粒子を解砕し、以下実施例１と同様の操作を行いトナーとした。実施例１と同様の画出し試験の結果、１，０００枚程度で転写不良によるベタ部白抜けが発生し、さらに、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。
【０１３８】
＜比較例４＞
実施例１で得た含水率２２ｗｔ％の湿潤着色重合体粒子約３０ｋｇを解砕後、容量１００リットルのナウター型の真空乾燥機（ＮＸＶ−１型：ホソカワミクロン社製）を用いて乾燥を行った。乾燥条件として、ジャケット加熱温度５０℃，真空度２〜５ｋＰａで７時間乾燥を行った。この時点でトナー粒子の含水率を測定したところ０．１ｗｔ％であり、トナー粒子に残留している重合性単量体の含有量は、１９０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は７０％であった。
【０１３９】
得られたトナー粒子を解砕し、以下実施例１と同様の操作を行いトナーとした。実施例１と同様の画出し試験の結果、５００枚程度で転写不良によるベタ部白抜けが発生した。
【０１４０】
＜比較例５＞
実施例１で得た含水率２２ｗｔ％の湿潤着色重合体粒子約４０ｋｇを解砕後、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、６時間後にトナーを取り出し含水率を測定したところ、０．１ｗｔ％未満であった。また、トナー粒子に残留している重合性単量体含有量は、７０ｐｐｍであったが、トナー凝集によるダマの発生があり、目開き１４９μｍの篩いの通過率は７５％であった。また、乾燥機内壁部には、トナーの付着層がみられた。このトナーの付着層を取り出し含水率を測定したところ、０．１ｗｔ％未満であり、付着層中のトナー粒子に残留している重合性単量体の含有量は、２８０ｐｐｍであった。
【０１４１】
得られたトナー粒子を解砕し、以下実施例１と同様の操作を行いトナーとした。実施例１と同様の画出し試験の結果、１，０００枚程度で転写不良によるベタ部白抜けが発生し、さらに、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。
【０１４２】
実施例及び比較例における測定結果、評価結果を表１に示す。
【０１４３】
【表１】

＜実施例７＞
イオン交換水７１０重量部に０．１モル／リットル−Ｎａ₃ＰＯ₄水溶液４５０重量部を投入し６０℃に加温した後、クリアミキサー（エム・テクニック社製）を用いて３，５００回転／分にて撹拌した。これに１．０モル／リットル−ＣａＣｌ₂水溶液６８重量部を添加し、Ｃａ₃（ＰＯ₄）₂を含む水系媒体を得た。
【０１４４】
一方、分散質系は、
・スチレン単量体 １７０重量部
・ｎ−ブチルアクリレート ３０重量部
・Ｃ．Ｉ．ピグメントレッド１２２ １０重量部
・飽和ポリエステル ２０重量部
・サリチル酸金属化合物 ３重量部
・前記化合物（１） ２５重量部
（ＤＳＣにおけるピーク温度５９．４℃，ビッカース硬度１．５）
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とスチレン単量体１００重量部をアトライター（三井三池化工機社製）を用い３時間分散し、着色剤分散液を得た。次に、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。
【０１４５】
上記重合性単量体組成物を前記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、高速撹拌機からプロペラ撹拌羽根に撹拌機を変え、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。重合終了後、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、水洗を行い、含水率２２ｗｔ％の湿潤着色重合体粒子を得た。得られた重合体粒子の重量平均粒径は、６．５μｍであった。
【０１４６】
得られた湿潤着色重合体粒子を解砕後、連続瞬間気流乾操機（フラッシュドライヤーＦＪＤ−４：セイシン企業社製）を用いて乾燥を行った。乾燥条件として、９０℃の空気を線速度１６．５ｍ／秒で吹き込み、湿潤着色重合体粒子を２０ｋｇ／ｈｒで連続的に供給した。尚、乾燥に要した時間は０．７秒であった。含水率を測定したところ、０．１ｗｔ％であった。また、この時点でトナー粒子に残留している重合性単量体の量は、５３０ｐｐｍであった。トナー凝集によるダマの発生もなく、目開き１４９μｍの篩いの通過率は９７％であった。
【０１４７】
次に、取り出した一次乾燥トナー粒子約３０ｋｇを、容量１００リットルのナウター型の真空乾燥機（ＮＸＶ−１型：ホソカワミクロン社製）を用いて乾燥を行った。乾燥条件として、ジャケット加熱温度５０℃，真空度２〜５ｋＰａ，下部より窒素ガスを５．０Ｎリットル／ｍｉｎで供給し３時間乾燥を行った。この時点でトナー粒子に残留している重合性単量体の含有量は、２０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は９６％であった。
【０１４８】
得られたトナー粒子の断層写真の模式図を図５に示す。低軟化点物質である化合物（１）が外殻樹脂で覆われた構造を示している。
【０１４９】
得られたトナー粒子中の粗粉を分級により除去し、除去後のトナー粒子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重量部を外添してトナーとした。
【０１５０】
このトナーを用いて、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）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の画が得られた。また、有機半導体である感光体に、トナー融着、メモリーゴーストのような問題を生じなかった。さら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。また、ＯＨＰシートヘ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。
【０１５１】
また、３０℃／８０％ＲＨの環境下で同様な画出し試験を行ったところ、同様な結果が得られた。
【０１５２】
＜実施例８＞
実施例７で得た連続瞬間気流乾燥機で乾燥した一次乾燥トナー粒子約３０ｋｇを、実施例７と同じ真空乾燥機（ＮＸＶ−１型）を用い、下部より窒素ガスを供給せず、ジャケット加熱温度５０℃，真空度２〜５ｋＰａという条件で４時間乾燥を行った。この時点でトナー粒子に残留している重合性単量体の含有量は、４０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は９５％であった。
【０１５３】
得られたトナー粒子を、以下実施例７と同様の操作を行いトナーとした。さらに実施例７と同様の画出し評価を行ったところ、実施例７と同様に良好な画像が得られた。
【０１５４】
＜実施例９＞
実施例７で得た連続瞬間気流乾燥機で乾燥した一次乾燥トナー粒子約２０ｋｇを、容量５０リットルのリボコーン真空乾燥機（ＲＤ−５０型：大川原製作所社製）に投入し、５０℃，真空度０．７〜２ｋＰａで４時間乾燥を行った。目開き１４９μｍの篩いの通過率は９０％であった。また、トナー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。
【０１５５】
得られたトナー粒子を、以下実施例７と同様の操作を行いトナーとした。さらに実施例７と同様の画出し評価を行ったところ、実施例７と同様に良好な画像が得られた。
【０１５６】
＜実施例１０＞
まず、実施例７と同じ水系分散媒体を用意した。
【０１５７】
一方、分散質系として
・スチレン単量体 １８０重量部
・２−エチルヘキシルアクリレート ２０重量部
・グラフト化カーボンブラック １０重量部
・飽和ポリエステル １０重量部
・サリチル酸金属化合物 ５重量部
・パラフィンワックス（ｍ．ｐ．６５℃、ビッカーズ硬度１．６）４０重量部
上記処方のうち、グラフト化カーボンブラック、サリチル酸金属化合物とスチレン単量体１００重量部をアトライター（三井三池化工機社製）を用い３時間分散し、着色剤分散液を得た。次に、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。
【０１５８】
上記重合性単量体組成物を前記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、高速撹拌機からプロペラ撹拌羽根に撹拌機を変え、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。重合終了後、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、水洗を行い、含水率２３ｗｔ％の湿潤着色重合体粒子を得た。
【０１５９】
次に、得た含水率２３ｗｔ％の湿潤着色重合体粒子を解砕後、実施例７と同様に、連続瞬間気流乾燥機（フラッシュドライヤーＦＪＤ−４）を用いて乾燥を行った。乾燥条件として、９０℃の空気を線速度１６．５ｍ／秒で吹き込み、湿潤着色重合体粒子を３５ｋｇ／ｈｒで連続的に供給した。含水率を測定したところ、０．１ｗｔ％であった。また、この時点でトナー粒子に残留している重合性単量体の含有量は、６５０ｐｐｍであった。トナー粒子の凝集によるダマの発生もなく、目開き１４９μｍの篩いの通過率は９６％であった。
【０１６０】
次に、実施例７と同様にナウター型の真空乾燥機（ＮＸＶ−１型）を用いて、一次乾燥トナー粒子約３０ｋｇを乾燥した。乾燥条件として、ジャケット加熱温度５０℃，真空度２〜５ｋＰａ，下部より窒素ガスを５．０Ｎリットル／ｍｉｎで供給し３時間乾燥を行った。得られたトナー粒子に残留している重合性単量体の含有量は、３０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は９６％であった。また、トナーの重量平均粒径は６．１μｍであった。そのトナーの断層写真の模式図を図５に示す。低軟化点物質が外殻樹脂で覆われた構造を示している。
【０１６１】
得られたトナー粒子中の粗粉を分級により除去し、除去後のトナー粒子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１．２重量部を外添してトナーとした。
【０１６２】
このトナーを用いて、実施例７と同様の画出し評価を行ったところ、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の画が得られた。また、有機半導体である感光体に、トナー融着、メモリーゴーストのような問題を生じなかった。
【０１６３】
＜実施例１１＞
実施例１０で得た重合終了後のスラリーを冷却し、希塩酸を添加し、Ｃａ₃（ＰＯ₄）₂を溶解させた後、濾過、水洗を行い、得られた湿潤している着色重合体粒子を水と混合して着色重合体粒子を２５重量％含むスラリー得た。
【０１６４】
次に、この洗浄後のスラリーを連続瞬間気流乾燥機（フラッシュドライヤーＦＪＤ−４）に５ｋｇ／ｈｒで連続的に供給し、９０℃の空気を線速度１６．５ｍ／秒で吹き込み乾燥を行った。含水率を測定したところ、０．１ｗｔ％であった。また、この時点でトナー粒子に残留している重合性単量体の含有量は、６８０ｐｐｍであった。トナー凝集によるダマの発生もなく、目開き１４９μｍの篩いの通過率は９５％であった。
【０１６５】
次に、取り出した一次乾燥トナー粒子約３０ｋｇを、実施例１０と同様にナウター型の真空乾燥機（ＮＸＶ−１型）を用いて乾燥を行った。得られたトナー粒子に残留している重合性単量体の含有量は、７０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は９５％であった。
【０１６６】
得られたトナー粒子を、以下実施例１０と同様の操作を行いトナーとした。さらに実施例１０と同様の画出し評価を行ったところ、実施例１０と同様に良好な画像が得られた。
【０１６７】
＜比較例６＞
実施例７で得た連続瞬間気流乾燥機で乾燥した一次乾燥トナー粒子（含水率０．１ｗｔ％、トナー粒子に残留している重合性単量体の量５３０ｐｐｍ）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重量部を外添してトナーとした。
【０１６８】
さらに実施例７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、さらに、３０℃／８０％ＲＨの環境下１，５００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。
【０１６９】
＜比較例７＞
実施例７で得た含水率２２ｗｔ％の湿潤着色重合体粒子約４０ｋｇを解砕後、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時間後にトナーを取り出し含水率を測定したところ、０．１ｗｔ％であった。また、トナー粒子に残留している重合性単量体含有量は、１８０ｐｐｍであったが、トナー凝集によるダマの発生があり、目開き１４９μｍの篩いの通過率は８５％であった。また、乾燥機内壁部には、トナーの付着層がみられた。このトナーの付着層を取り出し含水率を測定したところ、０．１ｗｔ％であり、付着層中のトナー粒子に残留している重合性単量体の含有量は、３１０ｐｐｍであった。
【０１７０】
得られたトナー粒子に対し、以下実施例７と同様の操作を行いトナーとした。
【０１７１】
さらに実施例７と同様の画出し試験を行ったところ、耐久１，５００枚程度から転写不良によるベタ部白抜けが発生し、さらに、３０℃／８０％ＲＨの環境下４，５００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。
【０１７２】
＜比較例８＞
実施例７で得た含水率２２ｗｔ％の湿潤着色重合体粒子約３０ｋｇを解砕後、容量１００リットルのナウター型の真空乾燥機（ＮＸＶ−１型）を用いて乾燥を行った。乾燥条件として、ジャケット加熱温度５０℃，真空度２〜５ｋＰａで４時間乾燥を行った。この時点でトナー粒子の含水率を測定したところ０．３ｗｔ％であり、トナー粒子に残留している重合性単量体の含有量は、２９０ｐｐｍであった。また、目開き１４９μｍの篩いの通過率は７５％であった。
【０１７３】
得られたトナー粒子を解砕し、以下実施例７と同様の操作を行いトナーとした。
【０１７４】
さらに実施例７と同様の画出し試験の結果、１，０００枚程度で転写不良によるベタ部白抜けが発生し、４，０００枚程度から画像濃度の低下がみられ、さらに、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。
【０１７５】
＜比較例９＞
実施例１０で得た連続瞬間気流乾燥機で乾燥した一次乾燥トナー粒子（含水率０．１ｗｔ％、トナー粒子に残留している重合性単量体の量６５０ｐｐｍ）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１．２重量部を外添してトナーとした。
【０１７６】
さらに実施例１０と同様の画出し試験の結果、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、さらに、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。
【０１７７】
実施例及び比較例の乾燥処理条件及び乾燥品のデータを表２に示す。
【０１７８】
【表２】

【０１７９】
【発明の効果】
上述したように、本発明は、直接重合法によって得られたトナー粒子において、トナー粒子を良好に乾燥することができ、トナー粒子中に残存する未反応の重合性単量体を効率よく除去することのできるトナーの製造方法を提供するものである。
【図面の簡単な説明】
【図１】本発明に用いられる被乾燥物（湿潤粒子またはスラリー）を熱気流中で粉粒状に分散させ、高速熱気流と並流に送りながら瞬間的に乾燥する装置のシステムの一例を示す概略的図である。
【図２】本発明に用いられる真空式乾燥装置及び装置システムの一例を示す概略的断面図である。
【図３】本発明に用いられる真空式乾燥装置及び装置システムの他の一例を示す概略的断面図である。
【図４】実施例４で用いた、機械的振動を加えた流動層乾燥機を示す模式側断面図である。
【図５】低軟化点物質が内包されたトナーの断面を示す模式図である。
【図６】本発明に用いられる流動層を形成しつつ乾燥を行なう乾燥機の模式図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a latent image and a toner manufacturing method used in a toner jet recording method.
[0002]
[Prior art]
As described in U.S. Pat. No. 2,297,691, etc., a number of methods are known for electrophotography. Generally, a photoconductive material is used on a photoreceptor by various means. An electric latent image is formed, and then the latent image is developed using toner, and the toner image is transferred to a transfer member such as paper as necessary, and then fixed by heating, pressure, solvent vapor, or the like. Get. Various methods have been proposed in the past as a method for developing with toner or a method for fixing a toner image, and a method suitable for each image forming process is employed.
[0003]
Conventionally, as a toner used for these purposes, generally, a colorant such as a dye and a pigment is melt-mixed in a thermoplastic resin and uniformly dispersed, and then a toner having a desired particle size is produced by a fine pulverizer and a classifier. I have done it.
[0004]
While this method of manufacture can produce fairly good toners, it has certain limitations, i.e., limited choice of toner materials. For example, the resin colorant dispersion must be sufficiently brittle and capable of being finely pulverized with economically possible production equipment. However, if the resin colorant dispersion is made brittle to satisfy these requirements, the particle size range of the particles formed when actually pulverized at high speed tends to be widened. It is included in the problem. Further, such a highly brittle material is likely to be further pulverized or powdered when used for development in a copying machine or the like. Also, with 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 increase in fog, the decrease in image density, and the color mixing / transparency may be difficult. Care must be taken to disperse as it will cause defects. Further, exposure of the colorant to the fracture surface may cause a change in development characteristics.
[0005]
On the other hand, in order to overcome the problems of the toner by the pulverization method, Japanese Patent Publication Nos. 36-10231, 43-10799, and 51-14895 propose a toner production method by suspension polymerization. . In the suspension polymerization method, a monomer composition is obtained by uniformly dissolving or dispersing a polymerizable monomer, a colorant, a polymerization initiator and, if necessary, a crosslinking agent, a charge control agent, and other additives. The monomer composition is dispersed in a continuous phase containing a dispersion stabilizer, such as an aqueous phase, using a suitable stirrer, and at the same time, a polymerization reaction is performed to obtain toner particles having a desired particle size.
[0006]
Since this method does not include a pulverization process, the toner does not need to be brittle, a soft material can be used, and the classification process can be omitted, thereby saving energy and saving time. Cost reduction effects such as shortening and improving process yield are significant.
[0007]
In recent years, there has been a demand for multifunctional toners such as high image quality, full color, and energy saving in recent copying machines and printers. For example, the toner particles have a small particle size to cope with high-resolution, digital methods with a finer particle size, improved transparency of OHP images with full color, and low-temperature fixing with energy saving. There is a demand for the inclusion of a softening point substance and the formation of toner particles that are effective in improving the transfer efficiency to a transfer material. As a means for realizing these requirements, a toner by a polymerization method is exemplified.
[0008]
On the other hand, in the suspension polymerization method, including the suspension polymerization method toner, the reaction mode of the polymerization increases as the polymerization progresses, and it becomes difficult to move radicals and polymerizable monomers in the polymer. Many polymerizable monomer components tend to remain. In particular, in the case of a suspension polymerization method toner, the polymerizable monomer system contains components such as dyes, pigments (particularly carbon black), charge control agents, and magnetic substances that may inhibit the polymerization reaction. Since it exists in a large amount other than the body, unreacted polymerizable monomers are likely to remain.
[0009]
If these toner particles contain many components that act as a solvent for the binder resin as well as the polymerizable monomer, the fluidity of the toner is lowered and the image quality is deteriorated, and the blocking resistance is lowered. . In addition to the performance directly related to toner, especially when using an organic semiconductor as the photoconductor, there are problems associated with photoconductor degradation such as memory ghosting and image blur, in addition to toner fusing to the photoconductor drum. May cause dots. In addition to the matters related to the performance of the product, there is a problem in that the polymerizable monomer component volatilizes and generates a bad odor at the time of fixing.
[0010]
In order to improve the above, as described in JP-A-7-92736, the residual amount of polymerizable monomer present in the toner particles is reduced to 500 ppm or less, thereby further improving the image quality. It is proposed to produce.
[0011]
Furthermore, along with the downsizing and personalization of copying machines, printers, etc., restrictions on the apparatus have increased, the burden on the above-mentioned problems has increased, and interest in the environment has increased, and the polymerizability present in the toner particles has increased. It is preferable to reduce the residual amount of monomer to 200 ppm or less, and more preferably to 100 ppm or less.
[0012]
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 suspension polymerization is used. Can do. For example, as a method of removing the unreacted polymerizable monomer, a method of washing with a highly volatile organic solvent that does not dissolve the toner binder resin but dissolves the polymerizable monomer and / or the organic solvent component; A method of washing with acid or alkali; a solvent component that does not dissolve the foaming agent or polymer is placed in the polymer system, and the resulting toner is made porous to reduce the volatilization area of the internal polymerizable monomer and / or organic solvent component. The main synthetic monomer and / or organic solvent component is volatilized under dry conditions, but it is difficult to select a solvent such as elution of toner constituents due to a decrease in toner capsule properties and the residualness of the solvent. Therefore, the method of volatilizing the polymerizable monomer and / or the organic solvent component under dry conditions is most preferable.
[0013]
Conventionally, the drying method of toner particles after solid-liquid separation of the suspension after the polymerization reaction has been improved. For example, Japanese Patent Application Laid-Open No. 63-124055 proposes a method in which toner particles are suspended and suspended in a gas and dried while forming a fluidized bed. In addition, methods for drying toner particles using a fluidized bed dryer have been proposed in Japanese Patent Application Laid-Open Nos. 4-31966 and 8-179562.
[0014]
The toner particle drying method using the fluidized bed dryer can efficiently dry the toner. However, since the unreacted polymerizable monomer described above generally has a boiling point higher than that of water, it can be effectively removed only after the removal of moisture is almost completed. However, it cannot be removed effectively without sufficient reduction drying. However, when moisture is removed, particles with charging properties such as toner particles cause adhesion to the wall surface of the fluid chamber, and further, the particles adhered to the wall surface of the fluid chamber peel in a lump state, As a whole, problems such as non-removable removal of the unreacted polymerizable monomer and a decrease in the yield of toner particles occur.
[0015]
Japanese Patent Application Laid-Open No. 6-324517 discloses that the toner particles or the suspension obtained after solid-liquid separation of the suspension after the completion of the polymerization reaction are dispersed in the form of powder in a hot air stream as they are, and in parallel with the hot air stream. There has been proposed a drying method in which it is dried instantaneously while being sent to a stream.
[0016]
This method of drying toner particles by a hot air stream can remove water efficiently and continuously. However, the above-mentioned unreacted polymerizable monomer can hardly be removed by instantaneous drying.
[0017]
Japanese Patent Application Laid-Open No. 8-160662 proposes a drying method using a vacuum dryer.
[0018]
However, in this drying method, after removing the water by evaporation, further removal of the unreacted polymerizable monomer requires not only a very long drying time, but also the inside of the apparatus during the removal of the water. The toner is tightened and aggregated due to the vacuum state to form a compacted state. The formation of the compacted state becomes remarkable when the moisture content becomes 5 wt% or less because the cohesive force between the powders starts to increase rapidly from the increase in the powder temperature. When this compacted state is formed, adhesion and fusion occur on the wall surface of the apparatus, the stirring blade in the apparatus, etc., and the stable operation of the apparatus is hindered. Further, the toner particles are agglomerated, and the external additive does not adhere uniformly to the toner surface when externally adding to the toner particles in a later step, causing a problem in performance as a developer.
[0019]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner manufacturing method that solves the above-described problems.
[0020]
Specifically, an object of the present invention is to provide a toner production method in which toner particles obtained by a direct polymerization method are uniformly dried while removing an unreacted polymerizable monomer and drying efficiently. .
[0021]
It is another object of the present invention to provide a toner production method that can provide a high-quality image free from image defects caused by residual unreacted polymerizable monomer.
[0022]
[Means for Solving the Problems]
In 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 colored polymer particles, and then the colored polymer particles are washed. A step of dehydrating and producing wet colored polymer particles; with respect to the obtained wet colored polymer particles, the moisture contained in the wet colored polymer particles is reduced by a dryer using hot air. Until the water content of the wet colored polymer particles is 0.1 to 0.5 wt% Removing the toner particles to obtain toner particles; and further performing a vacuum drying using a vacuum dryer so that the residual amount of the polymerizable monomer remaining in the toner particles is 200 ppm or less. The present invention relates to a toner production method.
[0023]
Furthermore, the present invention provides a colored polymer particle obtained by polymerizing a polymerizable monomer composition containing at least a polymerizable monomer and a colorant in an aqueous dispersion medium to obtain a colored polymer particle. Washing the particles and preparing a slurry containing the washed colored polymer particles; in a dryer using hot air, the moisture contained in the wet colored polymer particles contained in the slurry Until the water content of the wet colored polymer particles is 0.1 to 0.5 wt% Removing the toner particles to obtain toner particles; and further performing a vacuum drying using a vacuum dryer so that the residual amount of the polymerizable monomer remaining in the toner particles is 200 ppm or less. The present invention relates to a toner production method.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
As a result of intensive studies, the present inventors have removed the aqueous dispersion medium from the wet colored polymer particles with a dryer using hot air, and then dried them with a vacuum dryer, thereby remaining in the toner particles. It has been found that a toner in which the remaining amount of the unreacted polymerizable monomer is removed to 200 ppm or less can be obtained efficiently.
[0025]
In the fluidized bed dryer used in the conventional method for producing a polymerized toner, in order to remove the remaining amount of the unreacted polymerizable monomer to 200 ppm or less, the water content is set to 0.1 wt% or less (as water content). After removal, it is necessary to continue drying, and as described above, when moisture is removed, particles with charging properties such as toner particles cause adhesion to the wall surface of the fluid chamber, and Particles adhering to the wall surface of the fluid chamber peel off in a lump state, and as a whole, the removal of unreacted polymerizable monomer becomes non-uniform, resulting in poor performance and workability as a developer. Caused problems.
[0026]
In addition, when drying is performed using a vacuum drying method from the beginning, a very long drying time is required, and when water is removed, the toner is agglomerated due to aggregation. When lumps occur, the external additive does not uniformly adhere to the surface of the toner particles when externally added to the toner particles in a later step, causing a problem in performance as a developer. Moreover, it is difficult to remove the unreacted polymerizable monomer remaining in the particles from the inside of the agglomerated dust, which becomes non-uniform and causes the problems described above.
[0027]
Hereinafter, the present invention will be described in more detail.
[0028]
In the method for producing a toner of the present invention, wet colored polymer particles obtained by polymerizing a polymerizable monomer composition, or a slurry containing wet colored polymer particles is used as a material to be dried. The previous wet colored polymer particles preferably have a water content of 40 wt% or less from the viewpoint of fluidity as a powder. Furthermore, 30 wt% or less is more preferable. The “moisture content” as used herein refers to the moisture content based on weight, that is, the ratio of the moisture weight to the total weight (the sum of the dry toner particle weight and the moisture weight), and was determined by a heat loss method at 105 ° C.
[0029]
The toner particles having such a moisture content can be easily obtained by a normal solid-liquid separation means (for example, filtration), but in order to obtain such a moisture content, preliminary drying may be performed.
[0030]
In the present invention, first, an object to be dried is dried using a dryer using hot air. This process is a process for the purpose of substantially eliminating the water content of the object to be dried, and drying is performed until the moisture content of the object to be dried becomes 0.1 to 0.5 wt%. It is preferably 0.1 to 0.3 wt%. When drying is performed so that the moisture content of the material to be dried is 0.1 to 0.5 wt%, aggregation of particles and adhesion to the wall surface of the dryer can be suppressed. Further, the time required for the process using the vacuum dryer performed after this process is shortened, and the toner can be efficiently manufactured.
[0031]
As a dryer using such hot air, a dryer that dries and suspends wet particles to form a fluidized bed, or a high-speed hot air that disperses the material to be dried in a hot air stream in a granular form. For example, a device that dries instantaneously while being fed in parallel with the flow can be used.
[0032]
As an apparatus for performing drying while forming a fluidized bed, an apparatus as shown in FIG. 6 may be mentioned.
[0033]
The drying apparatus as shown in FIG. 6 has a cylindrical shape as a whole, and along a gas flow path, a flowing air blowing chamber 51 provided with a hot air inlet 61, an eye plate 52 for rectifying gas, particles, and the like It is composed of flow chambers 53 and 54 in which a fluidized bed with gas is formed, a filter 56 for capturing particles, and an exhaust chamber 55 having an exhaust port 64. The exhaust port 64 is connected to an exhaust blower for exhaust.
[0034]
The dry raw material is supplied from the inlet 63 at the upper part of the drying chamber, and the dried product is discharged from the outlet 64 at the lower part of the drying chamber.
[0035]
The drying operation using this drying apparatus is performed as follows, for example. That is, the particles to be dried put into the fluidizing chamber are introduced from the fluidizing air blowing chamber, blown up by the hot air introduced through the countersink plate, and fluidized together with the gas. The particles to be dried that float in the drying chamber to form a fluidized bed are uniformly mixed with gas and dried in the fluidized bed.
[0036]
The particles to be dried blown up to the upper part 54 of the fluid chamber are captured by the filter 56. For example, by applying a backwash pulse to the filter, the particles to be dried are removed from the filter and returned downward.
[0037]
As an apparatus for instantaneously drying an object to be dried (slurry or wet particles) dispersed in a hot air stream and sending it in parallel with a high-speed hot air stream, for example, a loop type dryer as shown in FIG. An air dryer or the like having the tube 2 may be mentioned, but is not particularly limited.
[0038]
In the hot air dryer shown in FIG. 1, the compressed air heated to a predetermined temperature in the hot air generator 1 is discharged at supersonic speed by the air flow dispersion unit 3, and the material to be dried supplied from the slurry or wet particle supply device 6 is discharged. It is dispersed and dried instantaneously (0.5 to 10 seconds) in the loop type airflow drying tube 2. The airflow outlet 4 is placed inside a loop type airflow drying tube to classify the dried product and the undried product by the Coanda effect, and the dried product is separated from the airflow by the cyclone 5 and is taken out of the system from the outlet 7. be able to.
[0039]
Further, the coarse particles in the particles coming out of the drying tube 2 are separately classified by a classifier and returned to the material to be dried supplying apparatus 6, and only particles having a certain particle size range are supplied to the cyclone 5 to obtain desired toner particles. By obtaining, classification and drying can be performed continuously. In addition to the loop type described above, the drying tube type of the air dryer is a straight tube type, with an enlarged inner cylinder to increase the residence time, and deposits on the bottom of the horizontal tube by giving vortex motion to the particles. Various types of drying pipes such as a model for preventing the above can be used, but an air dryer having a loop type drying pipe as shown in FIG. 1 is particularly preferable.
[0040]
In a device that performs drying while sending an object to be dried and a high-speed hot air stream in parallel, it is preferable to use compressed air heated to 40 to 150 ° C., preferably 60 to 120 ° C., as the hot air stream. When the heating temperature is lower than 40 ° C., the drying efficiency is lowered. When the heating temperature is higher than 150 ° C., the toner is fused.
[0041]
As such an apparatus to be dried (slurry or wet particles) preferably used in the present invention, dispersed in a granular form in a high-speed hot air stream, and dried instantaneously while being sent in parallel with the hot air stream, Examples include flash jet dryers (manufactured by Seishin Company) and flash dryers (manufactured by Hosokawa Micron).
[0042]
Next, the vacuum dryer used after substantially removing the aqueous dispersion medium used in the present invention can be used without particular limitation as long as it is an apparatus capable of drying colored polymer particles in a vacuum or reduced pressure state. It is. When the polymer particles are dried using such an apparatus, the polymerizable monomer remaining in the polymer particles can be suitably removed simultaneously with moisture. For example, a vacuum drier having an aspect as shown in schematic side views in FIGS. 2 and 3 is preferably used. In this reduced pressure (vacuum) drying, if the pressure is high, volatile substances are reduced and the drying efficiency is lowered. Therefore, it is preferably performed at 13 kPa or less.
[0043]
In the present invention, the amount of the polymerizable monomer remaining in the toner particles is 200 ppm or less, preferably 150 ppm or less, and more preferably 100 ppm or less.
[0044]
When the polymerizable monomer is dried by using a vacuum dryer alone, as described above, the aggregation of the particles becomes a problem. In the present invention, first, a dryer using hot air is used. Since moisture contained in the polymer particles is removed, aggregation of the particles is suppressed.
[0045]
The agitating vacuum dryer of the embodiment shown in FIGS. 2 and 3 will be described in detail.
[0046]
The dryer shown in FIG. 2 is supplied with particles to be dried in an inverted conical drying container 32 and is dried. In the drying container 32, a driving device 33 disposed above the container 32 is provided. A screw-type stirring member 35 connected via a drive arm 34 is provided, and the stirring member 35 is configured to rotate along the inner peripheral surface of the container 32 while rotating. For this reason, in the dryer shown in FIG. 2, since the particles to be dried in the container 32 are repeatedly stirred and dispersed while being lifted upward from below, the particles to be dried are efficiently stirred and mixed throughout the container 32. The
[0047]
In addition, as shown in FIG. 2, in the upper part of the container 32, a raw material supply port 36 for supplying particles to be dried, a case where the inside of the container is decompressed, and a case where drying is performed while supplying gas. An exhaust port 37 for exhausting the gas in the container 32 is provided. An airtight lid 16 is attached to the raw material supply port 36, and the bag filter 10 is connected to the exhaust port 37. Further, a take-out port 38 for taking out the dried product is provided below the dryer with a take-out valve 39 connected thereto. When the pressure in the container 32 is reduced, the gas in the container 32 is exhausted from the exhaust port 37 through the bag filter 10 and the cold trap 20 by the vacuum pump 28.
[0048]
Further, as shown in FIG. 2, a jacket 11 is attached around the above-described drying container 32 to appropriately control the temperature in the drying container 32 and allow drying at a desired temperature. ing. Therefore, a gap is formed between the outer wall of the drying container 32 and the inner wall of the jacket 11, and the steam supply port 12 is provided in the jacket 11 so that heated steam and cooling water can be passed through the gap. Further, a cooling water supply port 13 and a discharge port 14 for steam and cooling water are provided. A steam generating boiler (not shown) is connected to the steam supply port 12, and a cooling water pump 15 is connected to the cooling water supply port 13.
[0049]
Further, the drying container 32 is provided with steam inlets 17 at two positions above and below the container 32. By increasing the amount of steam supplied from the steam inlet 17 on the lower side, It is comprised so that the stirring effect of a raw material may be acquired at the time of injection | pouring. Each of these steam inlets 17 is connected to a steam generating boiler 19 via an accumulator 18. The accumulator 18 is used to quickly feed saturated or superheated steam into the container 32. The accumulator 18 is effective in ending the heating of the raw material in the container 32 in a short time and bringing the raw material to an optimum drying temperature. .
[0050]
As described above, the decompression in the container 2 is performed by exhausting the gas in the container 2 from the exhaust port 37 through the bag filter 10 and the cold trap 20 by the vacuum pump 28, as shown in FIG. As described above, the inside of the bag filter 10 is partitioned into two upper and lower chambers by the partition plate 21. A cylindrical filter cloth 22 is suspended below the partition plate 21, an exhaust port 23 connected to the cold trap 20 is located above the partition plate 21, and a position above the center of the filter cloth 22. A cleaning nozzle 24 is disposed on the surface. The washing nozzle 24 is for intermittently jetting high-pressure air from the compressor 25 to wash the filter cloth 22 with reverse pressure. An accumulator 27 is attached between the filter 26 and the cleaning nozzle 24. This accumulator 27 compensates for the shortage of high-pressure air supply on the compressor 25 side, sends a constant amount of high-pressure air to the cleaning nozzle 24 in a stable state with little pressure fluctuation, and the flow rate of air passing through the filter 26 and It is provided to stabilize the filtration effect by the filter 26 while keeping the passage speed substantially constant.
[0051]
Further, the gas is supplied into the container 32 when drying under reduced pressure while supplying the gas, from a gas inlet 30 provided at the lower part of the apparatus. By drying under reduced pressure while supplying gas in this way, toner blocking that tends to occur in the lower part of the apparatus is suppressed, and evaporation of residual moisture or residual polymerizable monomer from the raw material particle surface is efficiently performed. To work as a carrier gas. Therefore, it is preferable to perform gas supply from the viewpoint of improving efficiency.
[0052]
The gas supplied into the drying container 32 becomes a humidified gas containing moisture from the raw material particles, residual polymerizable monomer, and the like, and is exhausted from the bag filter 10 through the exhaust port 23. The exhausted humidified gas is sent to the cold trap 20, and the condensed liquid such as moisture is discharged from the cold trap 20 as drain, while the gas component is a vacuum connected to the cold trap 20. The air is exhausted to the outside by the pump 28. A pump 29 for feeding cooling water is connected to the cold trap 20 so that the humidified gas can be cooled and gas-liquid separation can be performed efficiently.
[0053]
On the other hand, the dryer shown in FIG. 3 is configured such that a ribbon blade 40 having a double spiral structure rotates on a driving device 33 disposed on an upper portion of an inverted conical drying container 32. By adopting such a configuration, it is possible to repeatedly apply stirring and dispersion while lifting the material to be dried supplied in the container 32 from the bottom upward, so that the raw materials in the container 32 can be efficiently stirred and mixed throughout. Can do. Since the configuration of the other parts of the dryer shown in FIG. 3 is the same as that of the vacuum drying apparatus of FIG. 2, the description of this part is omitted.
[0054]
Specific examples of the vacuum dryer used after substantially removing the aqueous dispersion medium preferably used in the present invention include a Nauter mixer (manufactured by Hosokawa Micron), Ribocorn (manufactured by Okawara Seisakusho), SV mixer (Shinko Pantech). Etc.).
[0055]
As the toner used in the present invention, in order to faithfully develop finer latent image dots for higher image quality, the toner also has a finer particle diameter, specifically, a weight average particle diameter measured by a Coulter counter. Is preferably 4 to 8 μm, and a toner having a number distribution variation coefficient of 35% or less. With toner having a weight average particle size of less than 4 μm, a large amount of transfer residual toner is generated on the photosensitive member or intermediate transfer member due to poor transfer efficiency, causing uneven image unevenness due to fogging or transfer failure. The toner to be used is not preferable. Further, when the weight average particle diameter of the toner exceeds 8 μm, fusion to the member is likely to occur, and when the coefficient of variation of the toner number distribution exceeds 35%, the tendency is further increased.
[0056]
The variation coefficient of the toner number distribution is calculated by the following equation.
[0057]
[Outside 1]

[0058]
As a method for producing the toner of the present invention, suspension polymerization methods described in JP-B-36-10231, JP-A-59-53856, and JP-A-59-61842 can be used. is there.
[0059]
In the present invention, a so-called seed polymerization method in which a monomer is further adsorbed to the obtained polymer particles and then polymerized using a polymerization initiator can be suitably used in the present invention.
[0060]
In the present invention, from the viewpoint of fixing properties, it is necessary to include a large amount of a low softening point substance in the toner particles. Therefore, it is necessary to encapsulate the low softening point substance in the outer shell resin. As a specific method for embedding the low softening point substance, the polarity of the material in the aqueous medium is set to be smaller for the low softening point substance than the main monomer, and a small amount of a resin or monomer having a large polarity. Thus, toner particles having a so-called core-shell structure in which a low softening point substance is coated with an outer shell resin can be obtained. The particle size distribution control and particle size control of the toner particles can be done by changing the type and amount of the poorly water-soluble inorganic salt and the protective colloid dispersing agent and the mechanical equipment conditions such as the rotor peripheral speed, the number of passes, It can be performed by controlling the stirring conditions such as the shape of the stirring blade, the container shape, or the solid content concentration in the aqueous solution.
[0061]
The fact that the toner particles have a core-shell structure can be confirmed by observing the tomographic plane of the toner particles. Specifically, the observation of the tomographic plane of the toner particles is performed as follows. After sufficiently dispersing the toner in a room temperature curable epoxy resin, the cured product obtained by curing for 2 days in an atmosphere at a temperature of 40 ° C. was dyed with ruthenium tetroxide and, if necessary, osmium tetroxide in combination. Thereafter, a sliced sample was cut out using a microtome equipped with diamond teeth, and the tomographic morphology of the toner particles was measured using a transmission electron microscope (TEM). In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to provide contrast between materials by utilizing a slight difference in crystallinity between the low softening point substance used and the resin constituting the outer shell. A typical example is shown in FIG. It was observed that the toner produced in the examples described later has a structure in which a low softening point substance is encapsulated with an outer shell resin.
[0062]
Examples of the polymerizable monomer that can be used in the polymerized toner include styrene monomers such as styrene, o (m-, p-)-methylstyrene, m (p-)-ethylstyrene; methyl (meth) acrylate. , Ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, (Meth) acrylic acid ester monomers such as (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid dimethylaminoethyl, (meth) acrylic acid diethylaminoethyl; butadiene, isoprene, cyclohexene, (meth) acrylonitrile, acrylic A vinyl monomer such as acid amide is preferably used. These monomers are used alone or in general so that the theoretical glass temperature (Tg) described in the publication Polymer Handbook 2nd edition III-p139-192 (manufactured by John Wiley & Sons) shows 40-75 ° C. It is used by mixing appropriately. When the theoretical glass transition temperature is less than 40 ° C., there are problems in terms of storage stability of the toner and durability of the developer. On the other hand, when it exceeds 75 ° C., the fixing point is increased. In some cases, the color toners are not sufficiently mixed, resulting in poor color reproducibility. Further, the transparency of the OHP image is remarkably lowered, which is not preferable from the viewpoint of high image quality.
[0063]
In the present invention, it is particularly preferable to add a polar resin in addition to the outer shell resin in order to encapsulate the low softening point substance in the outer shell resin. As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin are preferably used. The polar resin is particularly preferably one containing no unsaturated group capable of reacting with the outer shell resin or the monomer. In the case of using a polar resin having an unsaturated group, a cross-linking reaction occurs between the monomer forming the outer shell resin layer and the polar resin, and as a full color toner, the color mixture becomes very high and the color mixture of four color toners is increased. It is not preferable because of the disadvantage of sex.
[0064]
The low softening point substance used in the present invention is preferably a compound having a main maximum peak value measured in accordance with ASTM D3418-8 of 40 to 90 ° C. When the maximum peak is less than 40 ° C., the self-cohesion force of the low softening point substance becomes weak, and as a result, the high temperature offset resistance becomes weak, which is not preferable for a full color toner. On the other hand, when the maximum peak exceeds 90 ° C., the fixing temperature becomes high, and it becomes difficult to appropriately smooth the surface of the fixed image, which is not preferable from the viewpoint of color mixing. Furthermore, in the case of obtaining a toner by a direct polymerization method, granulation and polymerization are carried out in an aqueous system, so if the temperature at the maximum peak value is high, a low softening point substance mainly precipitates during granulation and inhibits the suspension system. Therefore, it is not preferable.
[0065]
For example, DSC-7 manufactured by Perkin Elmer is used to measure the temperature of the maximum peak value. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. For the sample, an aluminum pan is used, an empty pan is set for control, and the measurement is performed at a heating rate of 10 ° C./min.
[0066]
Specifically, paraffin wax, polyolefin wax, Fischer tropish wax, amide wax, higher fatty acid, ester wax and derivatives thereof, or graft / block compounds thereof can be used. An ester wax having at least one long-chain ester moiety having 10 or more carbon atoms represented by the following general structural formula is particularly preferable in the present invention because it has an effect on high-temperature offset properties without inhibiting the transparency of OHP. Specific structural formulas of typical ester wax compounds preferable for the present invention are shown as general structural formula (1), general structural formula (2), and general structural formula (3) below.
[0067]
[Outside 2]

(In the formula, a and b represent an integer of 0 to 4, a + b is 4, and R ₁ And R ₂ Represents an organic group having 1 to 40 carbon atoms, and R ₁ And R ₂ And the difference in the number of carbon atoms is 10 or more. n and m represent an integer of 0 to 15, and n and m are not 0 at the same time. )
[0068]
[Outside 3]

(In the formula, a and b represent an integer of 0 to 4, a + b is 4, and R ₁ Represents an organic group having 10 to 40 carbon atoms, n and m represent integers of 0 to 15, and n and m are not 0 at the same time. )
[0069]
[Outside 4]

(Wherein, a and b represent an integer of 0 to 3, a + b is 3 or less, R ₁ And R ₂ Represents an organic group having 1 to 40 carbon atoms, and R ₁ And R ₂ And the difference in the number of carbon atoms is 10 or more. R _Three Represents an organic group having 1 or more carbon atoms, n and m represent an integer of 0 to 15, and n and m are not 0 at the same time. )
[0070]
The ester wax preferably used in the present invention preferably has a hardness of 0.5 to 5.0. The hardness of the ester wax is a value obtained by measuring a Vickers hardness using, for example, a dynamic ultra-micro hardness meter (DUH-200) manufactured by Shimadzu Corporation after preparing a cylindrical sample having a diameter of 20 mmφ and a thickness of 5 mm. The measurement conditions are as follows: a load of 0.5 g and a load speed of 9.67 mm / second are displaced by 10 μm and held for 15 seconds, and the resulting dent shape is measured to determine the Vickers hardness. When the hardness of the ester wax is less than 0.5, the pressure dependency and process speed dependency of the fixing device are increased, and the high temperature offset effect tends to be insufficient. On the other hand, when the hardness exceeds 5.0, the toner is stored. Since the stability is poor and the self-cohesive force of the wax itself is small, the high-temperature offset resistance tends to be insufficient. Specific compounds include the following compounds.
[0071]
[Outside 5]

[0072]
[Outside 6]

[0073]
[Outside 7]

[0074]
[Outside 8]

[0075]
In recent years, the need for full-color double-sided images has increased, and when a double-sided image is formed, the heating part of the fixing unit is also used when the toner image on the transfer paper first formed on the front side forms the next image on the back side. It is necessary to sufficiently consider the high-temperature offset resistance of the toner. Therefore, in the present invention, it is essential to add a large amount of a low softening point substance. Specifically, it is preferable to add 5 to 40% by weight of a low softening point substance in the toner. Addition of less than 5% by weight does not show sufficient high-temperature offset resistance, and the back side image tends to exhibit an offset phenomenon when fixing double-sided images. On the other hand, if it exceeds 40% by weight, coalescence of toner particles is likely to occur during granulation, and a product having a wide particle size distribution is likely to be generated, which is inappropriate for the present invention.
[0076]
As the colorant used in the present invention, carbon black, a magnetic material, and a color tone adjusted to black using a yellow / magenta / cyan colorant shown below can be used.
[0077]
As the yellow colorant, compounds typified by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168 are preferably used.
[0078]
As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, 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, 254 are particularly preferred.
[0079]
As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, and 66 can be particularly preferably used.
[0080]
These colorants can be used alone or in combination and further in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner. The colorant is added in an amount of 1 to 20 parts by weight based on 100 parts by weight of the resin.
[0081]
When a magnetic material is used as the black colorant, 40 to 150 parts by weight are added to 100 parts by weight of the resin, unlike other colorants.
[0082]
As the charge control agent used in the present invention, known ones can be used. However, a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is preferable. Further, when the direct polymerization method is used in the present invention, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous system is particularly preferable. As specific compounds, salicylic acid, naphthoic acid, dicarboxylic acid metal compounds, polymer compounds having sulfonic acid and carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, and calixarene are used as negative compounds. it can. As the positive system, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, and an imidazole compound are preferably used. The charge control agent is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin. However, in the present invention, it is not essential to add a charge control agent. When a two-component development method is used, frictional charging with a carrier is used, and even when a non-magnetic one-component blade coating development method is used, the blade Since frictional charging with the member or the sleeve member can also be used positively, it is not always necessary to include a charge control agent in the toner.
[0083]
Examples of the polymerization initiator that can be used in the polymerized toner according to the present invention include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 ′. An azo or diazo polymerization initiator such as azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide; Peroxide polymerization initiators such as methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide are used. The addition amount of the polymerization initiator varies depending on the desired degree of polymerization, but generally 0.5 to 20% by weight is added to the polymerizable monomer. The kind of the polymerization initiator varies slightly depending on the polymerization method, but can be used alone or in combination with reference to the 10-hour half-life temperature.
[0084]
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.
[0085]
In the polymerized toner according to the present invention, as a dispersant used when suspension polymerization using a dispersant is used, as an inorganic compound, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, Examples include magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. As organic compounds, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and salts thereof, and starch can be used by dispersing in an aqueous phase. These dispersants are preferably used in an amount of 0.2 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer.
[0086]
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 inorganic compound may be produced in a dispersion medium. For example, in the case of tricalcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution may be mixed under high stirring.
[0087]
Moreover, you may use 0.001-0.1 weight part of surfactant for fine dispersion of these dispersing agents. This is for accelerating the intended action of the dispersant. Specific examples thereof include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, Examples include potassium stearate and calcium oleate.
[0088]
In the toner manufacturing method of the present invention, the toner can be specifically manufactured by the following manufacturing method.
[0089]
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 the mixture is uniformly dissolved or dispersed by a homogenizer, an ultrasonic disperser or the like. The monomer system is dispersed in an aqueous phase containing a dispersant by a normal stirrer, homomixer, homogenizer or the like. Preferably, granulation is performed by adjusting the stirring speed and time so that the monomer droplets have a desired toner particle size. After that, 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 is preferably carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and in order to remove unreacted polymerizable monomers and by-products that cause odor during toner fixing, the latter half of the reaction, or the completion of the reaction. A part of the aqueous medium may be distilled off later. After completion of the reaction, the produced toner particles are recovered by washing and filtration and dried by the drying method according to the present invention. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.
[0090]
The water content of the toner particles of the present invention was measured by a heat loss method at 105 ° C.
[0091]
Quantification of the remaining amount of polymerizable monomer remaining in the toner particles was measured by gas chromatography using an internal standard method under the following conditions using 0.2 g of toner dissolved in 4 ml of tetrahydrofuran (THF). did.
[0092]

[0093]
The particle size distribution of the toner can be measured by various methods. In the present invention, the particle size distribution was performed using a Coulter counter.
[0094]
As a measuring device, a Coulter counter TA-II type (manufactured by Coulter Co., Ltd.) was used, and an interface (manufactured by Nikkiki) and CX-1 personal computer (manufactured by Canon) that output number average distribution and volume average distribution were connected to perform electrolysis. Prepare 1% NaCl aqueous solution using primary sodium chloride.
[0095]
As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added.
[0096]
The electrolyte in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Using the Coulter counter TA-II, 100 μm aperture is used as an aperture, and particles of 2 to 40 μm on the basis of the number are used. The particle size distribution is measured, and various values are obtained therefrom.
[0097]
【Example】
Hereinafter, the present invention will be specifically described by way of examples. However, this example does not limit the present invention.
[0098]
<Example 1>
0.1 mol / liter-Na in 710 parts by weight of ion-exchanged water _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 rpm using a clear mixer (M Technique Co., Ltd.). To this, 1.0 mol / liter-CaCl ₂ Add 68 parts by weight of aqueous solution and add Ca. _Three (PO _Four ) ₂ An aqueous medium containing was obtained.
[0099]
On the other hand, the dispersoid system is
・ 170 parts by weight of styrene monomer
・ 30 parts by weight of n-butyl acrylate
・ Grafted carbon black 10 parts by weight
・ Saturated polyester 10 parts by weight
・ 3 parts by weight of salicylic acid metal compound
-25 parts by weight of the compound (1)
(Peak temperature 5DSC in DSC, Vickers hardness 1.5)
Among the above formulations, grafted carbon black, 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, the rest of the above formulation was added to the 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.
[0100]
The polymerizable monomer composition was put into the 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 for 10 hours at 50 rpm. After the polymerization is completed, the slurry is cooled, diluted hydrochloric acid is added, and Ca is added. _Three (PO _Four ) ₂ Then, filtration and washing were performed to obtain wet colored polymer particles having a water content of 22 wt%. The polymer particles obtained had a polymerization average particle size of 6.2 μm.
[0101]
About 40 kg of the obtained wet colored polymer particles were pulverized and then dried using a fluidized bed dryer (FBS-5 type: manufactured by Okawara Seisakusho) having the structure shown in FIG. As drying conditions, air at 50 ° C. was blown at a linear velocity of 0.4 m / sec. After 2 hours, the toner particles were taken out and the water content was measured. As a result, it was 0.3 wt%. At this time, the content of the polymerizable monomer remaining in the toner particles was 450 ppm. There was no occurrence of lumps due to aggregation of toner particles, and the passing rate of a sieve having an aperture of 149 μm was 96%. The “passing rate” here was obtained as follows.
[0102]
[Outside 9]

[0103]
Next, about 30 kg of the primary dried toner particles taken out were dried using a Nauter type vacuum dryer (NXV-1 type: manufactured by Hosokawa Micron Corporation) having a configuration as shown in FIG. As drying conditions, a drying operation was performed for 4 hours at a jacket heating temperature of 50 ° C. and a degree of vacuum of 2 to 5 kPa. At this time, the water content was 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles was 50 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 95%.
[0104]
A schematic diagram of the tomographic image of the toner particles obtained is shown in FIG. The compound (1), which is a low softening point substance, has a structure covered with an outer shell resin.
[0105]
The coarse particles in the obtained toner particles are removed by classification, and the specific surface area by the BET method is 200 m with respect to 100 parts by weight of the removed toner particles. ² A toner was obtained by externally adding 1.5 parts by weight of hydrophobic silica having a / g content.
[0106]
Using this toner, a color laser jet printer manufactured by Canon, and a color laser shot-2030 remodeling machine was used to perform an image print test in an environment of 23 ° C./65% RH. As a result, there was no change in the image density after the endurance, and a high-quality image with no voids was obtained. Further, problems such as toner fusion and memory ghost did not occur on the photoconductor which is an organic semiconductor. Further, double-sided images were formed, but no occurrence of offset was observed on the front and back surfaces of the transfer material.
[0107]
Further, when a similar image printing test was performed in an environment of 30 ° C./80% RH, the same good results were obtained.
[0108]
<Example 2>
Primary drying toner particles were obtained in the same manner except that the drying time by the fluidized bed dryer of Example 1 was 1.5 hours. When the moisture content of the toner particles was measured, it was 0.7 wt%, and the amount of the polymerizable monomer remaining in the particles was 610 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 97%.
[0109]
Next, about 30 kg of the obtained primary dry toner particles were used in the same manner as in Example 1 except that the drying time was 5 hours, using a Nauta type vacuum dryer (NXV-1 type: manufactured by Hosokawa Micron). The toner particles were produced by drying. At this time, the water content was 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles was 90 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 95%.
[0110]
Silica was externally added to the obtained toner particles in the same manner as in Example 1 to prepare a toner.
[0111]
When the image formation evaluation similar to that in Example 1 was performed using the toner, a good image was obtained as in Example 1.
[0112]
<Example 3>
About 20 kg of primary dry toner particles obtained by drying and removing for 2 hours in the fluidized bed dryer of Example 1 is a 50 liter ribocorn vacuum dryer (RD-50 type: manufactured by Okawara Seisakusho Co., Ltd.) having the configuration shown in FIG. And vacuum drying was performed at 50 ° C. and a vacuum degree of 0.7 to 2 kPa. When the water content after 4 hours was measured, it was 0.1 wt%, and the passing rate of a sieve having an aperture of 149 µm was 90%. Further, the content of the polymerizable monomer remaining in the toner particles was 120 ppm.
[0113]
Further, a toner was prepared in the same manner as in Example 1 and evaluated for image output. As a result, a good image was obtained as in Example 1.
[0114]
<Example 4>
First, the same aqueous dispersion medium as in Example 1 was prepared.
[0115]
On the other hand, as a dispersoid system
・ 180 parts by weight of styrene monomer
・ 20 parts by weight of 2-ethylhexyl acrylate
・ C. I. Pigment Blue 15: 3 10 parts by weight
・ Saturated polyester 10 parts by weight
・ 5 parts by weight of salicylic acid metal compound
-25 parts by weight of the compound (1)
Among the above prescriptions, C.I. I. Pigment Blue 15: 3, 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 Co., Ltd.) to obtain a colorant dispersion. Next, the rest of the above formulation was added to the 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.
[0116]
The polymerizable monomer composition was put into the 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 for 10 hours at 50 rpm. After the polymerization is completed, the slurry is cooled, diluted hydrochloric acid is added, and Ca is added. _Three (PO _Four ) ₂ Then, filtration and washing were performed to obtain wet colored polymer particles having a water content of 23 wt%. The weight average particle diameter of the obtained polymer particles was 6.5 μm.
[0117]
Next, the obtained wet colored polymer particles having a moisture content of 23% were put into a cylindrical vertically long vibrating fluidized bed dryer as shown in FIG. 4 and dried.
[0118]
The drying apparatus as shown in FIG. 4 has a cylindrical shape as a whole, and forms a gas inlet 72, a pan plate 73 for rectifying the gas, and a fluidized bed of particles and gas along the gas flow path. A drying chamber 74, a filter 75 for capturing particles, and an exhaust port 76. The exhaust port 76 is connected to an exhaust blower for exhaust.
[0119]
In addition, two vibration motors (vibrators) 80 are attached to opposite side wall surfaces of the frame at the bottom of the drying chamber, so that the entire drying chamber can be vibrated. The amplitude of vibration can be adjusted by the mounting angle between unbalanced weights mounted at both ends of the shaft of the vibration motor, and the frequency can be arbitrarily set by an inverter.
[0120]
The dry raw material is supplied from an input port 78 at the top of the drying chamber, and the dried product is discharged from a discharge port 79 at the bottom of the drying chamber.
[0121]
The drying operation using this drying apparatus is performed as follows, for example. That is, the particles to be dried thrown into the drying chamber are blown up by the mechanical vibration given by the vibration motor and the hot air introduced through the gas inlet, and flowed together with the gas. Turn into. The particles to be dried that float in the drying chamber to form a fluidized bed are uniformly mixed with gas and dried in the fluidized bed.
[0122]
The particles to be dried blown up to the top of the drying chamber 74 (exhaust port 76 side) are captured by the filter 75. For example, by applying a backwash pulse to the filter, the particles to be dried are removed from the filter. Returned downward.
[0123]
In this example, as drying conditions, vibration with a frequency of 25 Hz and an amplitude of 2.5 mm was applied, and air at 50 ° C. was blown from the bottom at a linear velocity of 0.2 m / sec. The toner was taken out after 2 hours and the water content was measured and found to be 0.3 wt%. At this time, the amount of the polymerizable monomer remaining in the toner particles was 400 ppm. There was little occurrence of lumps due to toner aggregation, and the passing rate of a sieve having an aperture of 149 μm was 94%.
[0124]
Next, about 30 kg of the taken out primary dry toner particles were dried using a Nauta type vacuum dryer (NXV-1 type: manufactured by Hosokawa Micron Corporation) in the same manner as in Example 1 to produce toner particles. At this time, the water content was 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles was 40 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 93%.
[0125]
Further, toner was prepared in the same manner as in Example 1 and image output was evaluated. As a result, a good image was obtained as in Example 1. Further, when an image was formed on an OHP sheet, an image with good transparency was obtained.
[0126]
<Example 5>
Primary dry toner particles were obtained in the same manner except that the drying time in the fluidized bed dryer in Example 1 was 3 hours. When the water content of the toner particles was measured, it was 0.1 wt%, and the amount of the polymerizable monomer remaining in the particles was 310 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 92%.
[0127]
Next, about 30 kg of the obtained primary dry toner particles were dried in the same manner as in Example 1 for 4 hours using a Nauter type vacuum dryer to produce toner particles. At this time, the water content was 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles was 40 ppm. The passing rate of the sieve having an aperture of 149 μm was 91%.
[0128]
Further, a toner was prepared in the same manner as in Example 1 and evaluated for image output. As a result, a good image was obtained as in Example 1.
[0129]
<Example 6>
About 30 kg of the primary dry toner particles which were dried for 2 hours in the fluidized bed dryer of Example 1 and taken out were dried using the Nauter type vacuum dryer used in Example 1 under the following conditions. The jacket heating temperature was 50 ° C., the degree of vacuum was 2 to 5 kPa, and nitrogen gas was supplied from the bottom at 0.5 N liter / min, and drying was performed for 3 hours. At this point, the water content was 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles was 30 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 96%.
[0130]
Further, a toner was prepared in the same manner as in Example 1 and evaluated for image output. As a result, a good image was obtained as in Example 1.
[0131]
<Comparative Example 1>
About 40 kg of wet colored polymer particles having a water content of 22% obtained in Example 1 were crushed and 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 toner was taken out and the water content was measured. As a result, it was less than 0.1 wt%. Further, the content of the polymerizable monomer remaining in the toner particles was 180 ppm, but there was an occurrence of lumps due to toner aggregation, and the passing rate of a sieve having an aperture of 149 μm was 85%. Further, a toner adhesion layer was observed on the inner wall of the dryer. The toner adhesion layer was taken out and the water content was measured. As a result, it was less than 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles in the adhesion layer was 310 ppm.
[0132]
The obtained toner was treated in the same manner as in Example 1 to obtain a toner.
[0133]
When the same image output test was performed, solid portion white spots due to poor transfer occurred from about 1,500 sheets of durability, and further, on the photosensitive member at about 4,500 sheets in an environment of 30 ° C./80% RH. An image defect due to toner fusion occurred.
[0134]
<Comparative Example 2>
Wet colored polymer particles having a water content of 22 wt% obtained in Example 1 were dispersed on an aluminum pad and vacuum dried at 50 ° C. and a vacuum degree of 3 kPa. When the water content after 2 hours was measured, it was 12 wt%. Drying was further performed for 16 hours until the water content became 0.1 wt% or less to obtain a dry toner. The obtained toner particles were partially agglomerated, and the passing rate of a sieve having an aperture of 149 μm was 70%. Further, the content of the polymerizable monomer remaining in the toner particles was 180 ppm.
[0135]
The obtained toner particles were pulverized and the same operation as in Example 1 was performed to obtain a toner. When the same image formation evaluation as in Example 1 was performed, solid portion white spots due to transfer failure occurred from about 500 durability sheets.
[0136]
<Comparative Example 3>
About 30 kg of wet colored polymer particles having a water content of 22 wt% obtained in Example 1 were crushed and dried using a Nauter type vacuum dryer (NXV-1 type: manufactured by Hosokawa Micron Corporation) having a capacity of 100 liters. . As drying conditions, drying was performed for 4 hours at a jacket heating temperature of 50 ° C. and a degree of vacuum of 2 to 5 kPa. At this time, the water content of the toner particles was measured and found to be 0.3% wt. The content of the polymerizable monomer remaining in the toner particles was 520 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 75%.
[0137]
The obtained toner particles were pulverized and the same operation as in Example 1 was performed to obtain a toner. As a result of the same image output test as in Example 1, solid white spots occur due to poor transfer at about 1,000 sheets, and further to the photosensitive member at about 2,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to toner fusion.
[0138]
<Comparative Example 4>
About 30 kg of wet colored polymer particles having a water content of 22 wt% obtained in Example 1 were crushed and dried using a Nauter type vacuum dryer (NXV-1 type: manufactured by Hosokawa Micron Corporation) having a capacity of 100 liters. . As drying conditions, drying was performed for 7 hours at a jacket heating temperature of 50 ° C. and a degree of vacuum of 2 to 5 kPa. At this time, the water content of the toner particles was measured and found to be 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles was 190 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 70%.
[0139]
The obtained toner particles were pulverized and the same operation as in Example 1 was performed to obtain a toner. As a result of the same image output test as in Example 1, solid white spots occurred due to transfer defects in about 500 sheets.
[0140]
<Comparative Example 5>
About 40 kg of wet colored polymer particles having a water content of 22 wt% obtained in Example 1 were crushed and 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 6 hours, the toner was taken out and the water content was measured. As a result, it was less than 0.1 wt%. Further, the content of the polymerizable monomer remaining in the toner particles was 70 ppm. However, the toner particles were agglomerated, and the passing rate of the sieve having a mesh size of 149 μm was 75%. Further, a toner adhesion layer was observed on the inner wall of the dryer. The toner adhesion layer was taken out and the water content was measured. As a result, it was less than 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles in the adhesion layer was 280 ppm.
[0141]
The obtained toner particles were pulverized and the same operation as in Example 1 was performed to obtain a toner. As a result of the same image output test as in Example 1, solid white spots occur due to poor transfer at about 1,000 sheets, and further to the photosensitive member at about 2,000 sheets in an environment of 30 ° C./80% RH. An image defect occurred due to toner fusion.
[0142]
The measurement results and evaluation results in the examples and comparative examples are shown in Table 1.
[0143]
[Table 1]

<Example 7>
0.1 mol / liter-Na in 710 parts by weight of ion-exchanged water _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 rpm using a clear mixer (M Technique Co., Ltd.). To this, 1.0 mol / liter-CaCl ₂ Add 68 parts by weight of aqueous solution and add Ca. _Three (PO _Four ) ₂ An aqueous medium containing was obtained.
[0144]
On the other hand, the dispersoid system is
・ 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
-25 parts by weight of the compound (1)
(Peak temperature 5DSC in DSC, Vickers hardness 1.5)
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 Co., Ltd.) to obtain a colorant dispersion. Next, the rest of the above formulation was added to the 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.
[0145]
The polymerizable monomer composition was put into the 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 for 10 hours at 50 rpm. After the polymerization is completed, the slurry is cooled, diluted hydrochloric acid is added, and Ca is added. _Three (PO _Four ) ₂ Then, filtration and washing were performed to obtain wet colored polymer particles having a water content of 22 wt%. The weight average particle diameter of the obtained polymer particles was 6.5 μm.
[0146]
The obtained wet colored polymer particles were crushed and then dried using a continuous instantaneous airflow dryer (flash dryer FJD-4: manufactured by Seishin Enterprise Co., Ltd.). As drying conditions, 90 ° C. air was blown at a linear velocity of 16.5 m / sec, and wet colored polymer particles were continuously supplied at 20 kg / hr. The time required for drying was 0.7 seconds. The water content was measured and found to be 0.1 wt%. At this time, the amount of the polymerizable monomer remaining in the toner particles was 530 ppm. There was no occurrence of lumps due to toner aggregation, and the passing rate of a sieve having an aperture of 149 μm was 97%.
[0147]
Next, about 30 kg of the primary dried toner particles taken out were dried using a 100 liter Nauter type vacuum dryer (NXV-1 type: manufactured by Hosokawa Micron Corporation). As drying conditions, the jacket heating temperature was 50 ° C., the degree of vacuum was 2 to 5 kPa, and nitrogen gas was supplied from the bottom at 5.0 N liters / min to perform drying for 3 hours. At this time, the content of the polymerizable monomer remaining in the toner particles was 20 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 96%.
[0148]
A schematic diagram of the tomographic image of the toner particles obtained is shown in FIG. This shows a structure in which the compound (1), which is a low softening point substance, is covered with an outer shell resin.
[0149]
The coarse particles in the obtained toner particles are removed by classification, and the specific surface area by the BET method is 200 m with respect to 100 parts by weight of the removed toner particles. ² A toner was prepared by externally adding 1.5 parts by weight of hydrophobic silica having a / g content.
[0150]
Using this toner, an image printing test was conducted in a 23 ° C / 65% RH environment using a Canon color laser jet printer (color laser shot-2030) modified machine. As a result, there was no change in the image density between the initial stage and after the endurance, and a high-quality image with no void was obtained. Further, problems such as toner fusion and memory ghost did not occur on the photoconductor which is an organic semiconductor. 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.
[0151]
Further, the same image output test was performed in an environment of 30 ° C./80% RH, and similar results were obtained.
[0152]
<Example 8>
About 30 kg of the primary dry toner particles dried by the continuous instantaneous air flow dryer obtained in Example 7 was heated by using the same vacuum dryer (NXV-1 type) as in Example 7 without supplying nitrogen gas from the lower part and jacket heating. Drying was performed for 4 hours under the conditions of a temperature of 50 ° C. and a degree of vacuum of 2 to 5 kPa. At this time, the content of the polymerizable monomer remaining in the toner particles was 40 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 95%.
[0153]
The obtained toner particles were treated in the same manner as in Example 7 to obtain toner. Further, the same image output evaluation as in Example 7 was performed, and as a result, a good image was obtained as in Example 7.
[0154]
<Example 9>
About 20 kg of the primary dry toner particles dried by the continuous instantaneous air flow dryer obtained in Example 7 was put into a 50 liter ribocorn vacuum dryer (RD-50 type: manufactured by Okawara Seisakusho Co., Ltd.) at 50 ° C. and the degree of vacuum. Drying was performed at 0.7 to 2 kPa for 4 hours. The passing rate of the sieve having a mesh size of 149 μm was 90%. Further, the content of the polymerizable monomer remaining in the toner particles was 80 ppm.
[0155]
The obtained toner particles were treated in the same manner as in Example 7 to obtain toner. Further, the same image output evaluation as in Example 7 was performed, and as a result, a good image was obtained as in Example 7.
[0156]
<Example 10>
First, the same aqueous dispersion medium as in Example 7 was prepared.
[0157]
On the other hand, as a dispersoid system
・ 180 parts by weight of styrene monomer
・ 20 parts by weight of 2-ethylhexyl acrylate
・ Grafted carbon black 10 parts by weight
・ Saturated polyester 10 parts by weight
・ 5 parts by weight of salicylic acid metal compound
・ 40 parts by weight of paraffin wax (mp 65 ° C., Vickers hardness 1.6)
Among the above formulations, grafted carbon black, 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 Co., Ltd.) to obtain a colorant dispersion. Next, the rest of the above formulation was added to the 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.
[0158]
The polymerizable monomer composition was put into the 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 for 10 hours at 50 rpm. After the polymerization is completed, the slurry is cooled, diluted hydrochloric acid is added, and Ca is added. _Three (PO _Four ) ₂ Then, filtration and washing were performed to obtain wet colored polymer particles having a water content of 23 wt%.
[0159]
Next, the obtained wet colored polymer particles having a water content of 23 wt% were crushed and dried in the same manner as in Example 7 using a continuous instantaneous air flow dryer (flash dryer FJD-4). As drying conditions, 90 ° C. air was blown at a linear velocity of 16.5 m / sec, and wet colored polymer particles were continuously supplied at 35 kg / hr. The water content was measured and found to be 0.1 wt%. At this time, the content of the polymerizable monomer remaining in the toner particles was 650 ppm. There was no occurrence of lumps due to aggregation of toner particles, and the passing rate of a sieve having an aperture of 149 μm was 96%.
[0160]
Next, about 30 kg of primary dry toner particles were dried using a Nauter type vacuum dryer (NXV-1 type) in the same manner as in Example 7. As drying conditions, the jacket heating temperature was 50 ° C., the degree of vacuum was 2 to 5 kPa, and nitrogen gas was supplied from the bottom at 5.0 N liters / min to perform drying for 3 hours. The content of the polymerizable monomer remaining in the obtained toner particles was 30 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 96%. The weight average particle diameter of the toner was 6.1 μm. A schematic diagram of the tomographic image of the toner is shown in FIG. This shows a structure in which a low softening point material is covered with an outer shell resin.
[0161]
The coarse particles in the obtained toner particles are removed by classification, and the specific surface area by the BET method is 200 m with respect to 100 parts by weight of the removed toner particles. ² A toner was prepared by externally adding 1.2 parts by weight of hydrophobic silica having a / g content.
[0162]
Using this toner, the same image output evaluation as in Example 7 was performed. As a result, there was no change in the image density after the endurance and after the endurance at the end of 5,000 sheets, and a high-quality image with no void was obtained. Obtained. Further, problems such as toner fusion and memory ghost did not occur on the photoconductor which is an organic semiconductor.
[0163]
<Example 11>
The slurry after completion of polymerization obtained in Example 10 was cooled, diluted hydrochloric acid was added, and Ca was added. _Three (PO _Four ) ₂ Then, filtration and washing were performed, and the resulting wet colored polymer particles were mixed with water to obtain a slurry containing 25% by weight of the colored polymer particles.
[0164]
Next, the washed slurry was continuously supplied to a continuous instantaneous air dryer (flash dryer FJD-4) at 5 kg / hr, and 90 ° C. air was blown at a linear velocity of 16.5 m / sec for drying. . The water content was measured and found to be 0.1 wt%. At this time, the content of the polymerizable monomer remaining in the toner particles was 680 ppm. There was no occurrence of lumps due to toner aggregation, and the passing rate of a sieve having an aperture of 149 μm was 95%.
[0165]
Next, about 30 kg of the primary dried toner particles taken out were dried using a Nauter type vacuum dryer (NXV-1 type) in the same manner as in Example 10. The content of the polymerizable monomer remaining in the obtained toner particles was 70 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 95%.
[0166]
The obtained toner particles were treated in the same manner as in Example 10 to obtain toner. Further, the same image formation evaluation as in Example 10 was performed, and as a result, a good image was obtained as in Example 10.
[0167]
<Comparative Example 6>
The BET method was performed on 100 parts by weight of the primary dry toner particles (water content 0.1 wt%, amount of polymerizable monomer remaining in the toner particles 530 ppm) dried by the continuous instantaneous air dryer obtained in Example 7. Specific surface area by 200m ² A toner was prepared by externally adding 1.5 parts by weight of hydrophobic silica having a / g content.
[0168]
Further, the same image output test as in Example 7 was performed. As a result, solid portion white spots due to transfer failure occurred from about 500 sheets, and the image density decreased from about 2,000 sheets. Image defects due to toner fusion to the photoreceptor occurred at about 1,500 sheets in an 80% RH environment.
[0169]
<Comparative Example 7>
About 40 kg of wet colored polymer particles having a water content of 22 wt% obtained in Example 7 were crushed and 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 / sec. After 4 hours, the toner was taken out and the water content was measured. As a result, it was 0.1 wt%. Further, the content of the polymerizable monomer remaining in the toner particles was 180 ppm, but there was an occurrence of lumps due to toner aggregation, and the passing rate of a sieve having an aperture of 149 μm was 85%. Further, a toner adhesion layer was observed on the inner wall of the dryer. The toner adhesion layer was taken out and the water content was measured. As a result, it was 0.1 wt%, and the content of the polymerizable monomer remaining in the toner particles in the adhesion layer was 310 ppm.
[0170]
The obtained toner particles were subjected to the same operation as in Example 7 to obtain a toner.
[0171]
Further, when the same image output test as in Example 7 was performed, solid white spots due to poor transfer occurred from about 1,500 sheets of durability, and about 4,500 sheets under an environment of 30 ° C./80% RH. As a result, image defects due to toner fusion to the photoreceptor occurred.
[0172]
<Comparative Example 8>
About 30 kg of wet colored polymer particles having a water content of 22 wt% obtained in Example 7 were crushed and dried using a Nauter type vacuum dryer (NXV-1 type) having a capacity of 100 liters. As drying conditions, drying was performed for 4 hours at a jacket heating temperature of 50 ° C. and a degree of vacuum of 2 to 5 kPa. At this time, the water content of the toner particles was measured and found to be 0.3 wt%, and the content of the polymerizable monomer remaining in the toner particles was 290 ppm. Further, the passing rate of the sieve having an aperture of 149 μm was 75%.
[0173]
The obtained toner particles were pulverized and the same operation as in Example 7 was performed to obtain a toner.
[0174]
Further, as a result of the same image printing test as in Example 7, solid white spots due to poor transfer occurred at about 1,000 sheets, and the image density decreased from about 4,000 sheets. Image defects due to toner fusion to the photoreceptor occurred at about 3,000 sheets in an 80% RH environment.
[0175]
<Comparative Example 9>
The BET method was performed on 100 parts by weight of the primary dry toner particles (water content 0.1 wt%, amount of polymerizable monomer remaining in the toner particles 650 ppm) dried by the continuous instantaneous air flow dryer obtained in Example 10. Specific surface area by 200m ² A toner was prepared by externally adding 1.2 parts by weight of hydrophobic silica having a / g content.
[0176]
Furthermore, as a result of the same image output test as in Example 10, solid white spots due to transfer failure occurred from about 500 sheets, and the image density decreased from about 2,000 sheets. Further, 30 ° C./80% Image defects due to toner fusion to the photoreceptor occurred at about 2,000 sheets in an RH environment.
[0177]
Table 2 shows the drying treatment conditions and the data of the dried products of Examples and Comparative Examples.
[0178]
[Table 2]

[0179]
【The invention's effect】
As described above, according to the present invention, in the toner particles obtained by the direct polymerization method, the toner particles can be dried well, and the unreacted polymerizable monomer remaining in the toner particles is efficiently removed. It is an object of the present invention to provide a toner manufacturing method that can be used.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an example of a system of an apparatus for instantly drying an object to be dried (wet particles or slurry) used in the present invention in a hot air stream and dispersed in a granular state while sending it in parallel with a high-speed hot air stream. FIG.
FIG. 2 is a schematic cross-sectional view showing an example of a vacuum drying apparatus and an apparatus system used in the present invention.
FIG. 3 is a schematic cross-sectional view showing another example of a vacuum drying apparatus and an apparatus system used in the present invention.
FIG. 4 is a schematic side sectional view showing a fluidized bed dryer used in Example 4 to which mechanical vibration is applied.
FIG. 5 is a schematic view showing a cross section of a toner containing a low softening point substance.
FIG. 6 is a schematic view of a dryer that performs drying while forming a fluidized bed used in the present invention.

Claims (17)

A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles, and then the colored polymer particles are washed, dehydrated, and wetted. Step for producing colored polymer particles; the moisture content of the wet colored polymer particles is 0.1 with respect to the water content of the wet colored polymer particles by a dryer using hot air with respect to the obtained wet colored polymer particles. Step of removing until 0.5 wt% to obtain toner particles; further drying with a vacuum dryer under reduced pressure so that the residual amount of polymerizable monomer remaining in the toner particles is 200 ppm or less A method for producing toner, comprising the step of:   2. The method for producing a toner according to claim 1, wherein the dryer using hot air is a dryer that dries while suspending wet colored polymer particles to form a fluidized bed.   The dryer using hot air is a dryer in which wet colored polymer particles are dispersed in a powder form in a hot air stream and dried while being conveyed in parallel with the hot air stream. Toner manufacturing method.   4. The toner production method according to claim 1, wherein the wet colored polymer particles are dried to a moisture content of 0.1 to 0.3 wt% by a dryer using hot air. Vacuum drying process using a vacuum dryer The method for producing a toner according to any one of claims 1 to 4, characterized in that is carried out while supplying a gas to the dryer. Vacuum drying process using vacuum dryer, drying the cabin pressure in an amount that kept below 13 kPa, according to any one of claims 1 to 4, characterized in that is carried out while supplying a gas to the dryer Toner manufacturing method. By a vacuum dryer, the residual amount of the polymerizable monomer remaining in the toner particles, according to any one of claims 1 to 6, characterized in that it is dried under reduced pressure to be 100ppm or less Toner production method. Toner particles, which contain 5 to 40 wt% of low softening point substance, according to any one of claims 1 to 7, characterized in that the low-softening substance is encapsulated by an outer shell resin layer Toner production method. Low softening point material, method for producing a toner according to any one of claims 1 to 8, characterized in that an ester wax having more than one long chain alkyl group having 10 or more carbon atoms. A polymerizable monomer composition containing at least a polymerizable monomer and a colorant is polymerized in an aqueous dispersion medium to produce colored polymer particles, and the resulting colored polymer particles are washed and washed. A step of producing a slurry containing the colored polymer particles formed; the moisture content of the wet colored polymer particles contained in the slurry by a dryer using hot air is from 0.1 to Step of removing until 0.5 wt% to obtain toner particles; further, using a vacuum dryer, drying under reduced pressure so that the residual amount of polymerizable monomer remaining in the toner particles is 200 ppm or less A toner production method comprising the steps of: Dryer with hot air, according to claim 10 in which the slurry containing wet colored polymer particles are dispersed in particulate during hot air, characterized in that it is a drier for drying while conveying the hot air flow and co-current 2. A method for producing the toner according to 1. Wet colored polymer particles, by drying machine using hot air method for producing a toner according to claim 10 or 11, characterized in that it is dried to a water content of 0.1 to 0.3 wt%. The method for producing a toner according to any one of claims 10 to 12 , wherein the vacuum drying step using a vacuum dryer is performed while supplying gas into the dryer. Vacuum drying process using a vacuum dryer is in an amount which holds the dryer pressure below 13 kPa, according to any one of claims 10 to 12, characterized in that is carried out while supplying a gas to the dryer Toner manufacturing method. By a vacuum dryer, the residual amount of the polymerizable monomer remaining in the toner particles, according to any one of claims 10 to 14, characterized in that it is dried under reduced pressure to be 100ppm or less Toner production method. Toner particles, which contain 5 to 40 wt% of low softening point substance, according to any one of claims 10 to 15, characterized in that said low-softening substance is encapsulated by an outer shell resin layer Toner production method. Low softening point material, method for producing a toner according to any one of claims 10 to 16, characterized in that an ester wax having at least one having 10 or more of long-chain alkyl group having a carbon.

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