JP4416243B2 - Method for producing polymerized toner - Google Patents

Description

（式中、ａ及びｂは０〜４迄の整数であり、ａ＋ｂは４である。Ｒ₁及びＲ₂は炭素数が１〜４０の有機基であり、Ｒ₁とＲ₂との炭素数差が３以上である。ｍ及びｎは０〜２５の整数であり、ｍとｎは同時に０になることはない。）
【００３７】
【化２】

（式中、ａ及びｂは０〜３の整数であり、ａ＋ｂは１〜３である。Ｒ₁及びＲ₂は炭素数が１〜４０の有機基であり、Ｒ₁とＲ₂との炭素数差が３以上である。Ｒ₃は水素原子、炭素数が１以上の有機基である。但し、ａ＋ｂ＝２のとき、Ｒ₃のどちらか一方は、炭素数が１以上の有機基である。ｋは１〜３の整数である。ｍ及びｎは０〜２５の整数であり、ｍとｎが同時に０になることはない。）
【００３８】
【化３】

（式中、Ｒ₁及びＲ₃は炭素数６〜３２を有する有機基であり、Ｒ₁とＲ₃は同じものであってもなくても良い。Ｒ₂は炭素数１〜２０を有する有機基を示す。）
【００３９】
【化４】

（式中、Ｒ₁及びＲ₂は炭素数６〜３２を有する有機基であり、Ｒ₁とＲ₃は同じものであってもなくてもよい。
Ｒ₂は−ＣＨ₂ＣＨ₂ＯＣ₆Ｈ₄ＯＣＨ₂ＣＨ₂−、

【００４０】
【化５】

（式中、ａは０〜４の整数であり、ｂは１〜４の整数であり、ａ＋ｂは４である。Ｒ₁は炭素数が１〜４０の有機基である。ｍ及びｎは０〜２５の整数であり、ｍとｎが同時に０になることはない。）
【００４１】
【化６】

（式中、Ｒ₁及びＲ₂は同一又は異なる炭素数１５〜４５の炭化水素基を示す。）
【００４２】
エステル系ワックスの融点としては４０〜１００℃が好ましい。融点が４０℃未満ではトナーの耐ブロッキング性及び保形性が不十分であり、１００℃を超えると離型効果が不十分となる。エステル化合物からなる離型剤としてのエステルワックスとして以下のものが例示される。
【００４３】
【化７】

【００４４】
【化８】

【００４５】
該離型剤が、上記構造式を有するエステル化合物を有するエステルワックスの場合、良好な透明性を発現するとともに、トナー粒子中に含有せしめた場合には良好な定着性を示すものである。
【００４６】
また、離型剤は、本発明においては、重合性単量体１００質量％に対して５乃至４０質量％（より好ましくは１０〜３０質量％）配合し、結果として、重合性単量体から生成された結着樹脂１００質量％当り離型剤５乃至４０質量％（より好ましくは１０〜３０質量％）トナー粒子に含有されるのが良い。
【００４７】
本発明のトナーは荷電制御剤を含有してもよい。
【００４８】
荷電制御剤としては、公知のものが利用できるが、例えばトナーを負荷電性に制御するものとしては、有機金属化合物、キレート化合物が有効であり、モノアゾ金属化合物、アセチルアセトン金属化合物、芳香族ハイドロキシカルボン酸、芳香族ダイカルボン酸系の金属化合物がある。他には、芳香族ハイドロキシカルボン酸、芳香族モノ及びポリカルボン酸及びその金属塩、無水物、エステル類、ビスフェノール等のフェノール誘導体類などがある。
【００４９】
また、尿素誘導体、含金属サリチル酸系化合物、４級アンモニウム塩、カリックスアレーン、ケイ素化合物、スチレン−アクリル酸共重合体、スチレン−メタクリル酸共重合体、スチレン−アクリルスルホン酸共重合体、ノンメタルカルボン酸系化合物等が挙げられる。
【００５０】
トナーを正荷電性に制御するものとしては、ニグロシン及び脂肪酸金属塩等による変性物、トリブチルベンジルアンモニウム−１−ヒドロキシ−４−ナフトスルフォン酸塩、テトラブチルアンモニウムテトラフルオロボレートなどの４級アンモニウム塩、及びこれらの類似体であるホスホニウム塩等のオニウム塩及びこれらのレーキ顔料、トリフェニルメタン染料及びこれらのレーキ顔料（レーキ化剤としては、りんタングステン酸、りんモリブデン酸、りんタングステンモリブデン酸、タンニン酸、ラウリン酸、没食子酸、フェリシアン化物、フェロシアン化物など）、高級脂肪酸の金属塩；ジブチルスズオキサイド、ジオクチルスズオキサイド、ジシクロヘキシルスズオキサイドなどのシオルガノスズオキサイド；ジブチルスズボレート、ジオクチルスズボレート、ジシクロヘキシルスズボレートなどのシオルガノスズボレート類；これらを単独で或は２種類以上組合せて用いることができる。これらの中でも、ニグロシン系、４級アンモニウム塩の如き荷電制御剤が特に好ましく用いられる。
【００５１】
これらの荷電制御剤は、樹脂成分１００質量％に対して、０．０１〜２０質量％（より好ましくは０．５〜１０質量％）使用するのが良い。
【００５２】
カラートナーの場合は、特に、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、重合法により得られるトナーの場合には、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。
【００５３】
重合性単量体を重合せしめる際に必要な重合開始剤として、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等のアゾ系重合開始剤；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、ｔ−ブチルペルオキシ−２−エチルヘキサノエート、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等の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単量体に対し０．５〜２０質量％添加され用いられる。開始剤の種類は、重合方法により若干異なるが、十時間半減期温度を参考に、単独又は混合し利用される。
【００５４】
架橋剤としては、例えば、ジビニルベンゼン、４，４’−ジビニルビフェニル、エチレングリコールジ（メタ）アクリレート、グリシジル（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート等の多官能性化合物を挙げることができる。
【００５５】
また、重合性単量体組成物を水性媒体中に良好に分散させるための分散安定剤として、例えば無機系酸化物である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，磁性体，フェライト等が挙げられる。有機系化合物としては例えば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，デンプン等が水相に分散させて使用される。これら分散安定剤は、重合性単量体１００質量％に対して０．２〜１０．０質量％を使用することが好ましい。
【００５６】
これら分散安定剤は、市販のものをそのまま用いても良いが、細かい均一な粒度を有す分散粒子を得るために、分散媒中にて高速撹拌下にて該無機化合物を生成させることもできる。例えば、リン酸三カルシウムの場合、高速撹拌下において、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ことで懸濁重合方法に好ましい分散剤を得ることができる。また、これら分散剤の微細化のため０．００１〜０．１質量％の界面活性剤を併用しても良い。具体的には市販のノニオン，アニオン，カチオン型の界面活性剤が利用でき、例えばドデシル硫酸ナトリウム，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等が好ましく用いられる。
【００５７】
懸濁重合のように水系分散媒を用いる重合法の場合には、該重合性単量体組成物に極性樹脂を添加することにより、離型剤の内包化の促進を図ることができる。水系媒体中の重合性単量体組成物中に極性樹脂が存在した場合、親水性の違いから極性樹脂が水系媒体と重合性単量体組成物の界面付近に移行するため、トナー表面に極性樹脂が偏在する。その結果トナー粒子はカプセル構造を有し、多量の離型剤を含有する場合でも、離型剤の内包性が良好になる。
【００５８】
該極性樹脂としては、トナー表面に偏在した際に、極性樹脂自身の流動性が期待できることから、特にポリエステル系樹脂が好ましい。
【００５９】
本発明のトナーに用いることができる極性樹脂としては、テレフタル酸、イソフタル酸、フタル酸、フマル酸、マレイン酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバシン酸、しょうのう酸、シクロヘキサンジカルボン酸、トリメリット酸の如き酸成分単量体と；エチレングリコール、ジエチレングリコール、トリエチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，４−ブタンジオール、ネオペンチルグリコール、１，４−ビス（ヒドロキシメチル）シクロヘキサン等のアルキレングリコール類及びポリアルキレングリコール類、ビスフェノールＡ、水素添加ビスフェノール、ビスフェノールＡのエチレンオキサイド付加物、ビスフェノールＡのプロピレンオキサイド付加物、グリセリン、トリメチロールプロパン、ペンタエリスリトールの如き多価アルコール単量体とを縮合重合したものを挙げることができる。
【００６０】
本発明により製造されるトナーを使用するにあたっては、各種特性付与を目的として外添剤を使用することができる。外添剤としては、トナーに添加した時の耐久性の点から、トナー粒子の重量平均径の１／１０以下の粒径であることが好ましい。この添加剤の粒径とは、電子顕微鏡におけるトナー粒子の表面観察により求めたその平均粒径を意味する。外添剤としては、たとえば、以下のようなものが用いられる。
【００６１】
金属酸化物（酸化アルミニウム，酸化チタン，チタン酸ストロンチウム，酸化セリウム，酸化マグネシウム，酸化クロム，酸化錫，酸化亜鉛など）・窒化物（窒化ケイ素など）・炭化物（炭化ケイ素など）・金属塩（硫酸カルシウム，硫酸バリウム，炭酸カルシウムなど）・脂肪酸金属塩（ステアリン酸亜鉛，ステアリン酸カルシウムなど）・カーボンブラック・シリカなど。
【００６２】
これら外添剤は、トナー粒子１００質量％に対し、０．０１〜１０質量％が用いられ、好ましくは、０．０５〜５質量％が用いられる。これら外添剤は、単独で用いても、また、複数併用しても良い。それぞれ、疎水化処理を行ったものが、より好ましい。
【００６３】
さらに本発明のトナーは、磁性材料を含有させ磁性トナーとしても使用しうる。この場合、磁性材料は着色剤の役割をかねることもできる。本発明において、磁性トナー中に含まれる磁性材料としては、マグネタイト、ヘマタイト、フェライト等の酸化鉄；鉄、コバルト、ニッケルのような金属或はこれらの金属のアルミニウム、コバルト、銅、鉛、マグネシウム、スズ、亜鉛、アンチモン、ベリリウム、ビスマス、カドミウム、カルシウム、マンガン、セレン、チタン、タングステン、バナジウムのような金属の合金及びその混合物等が挙げられる。
【００６４】
これらの強磁性体は平均粒子が２μｍ以下、好ましくは０．１〜０．５μｍ程度のものが好ましい。トナー中に含有させる量としては樹脂成分１００質量％に対し約２０〜２００質量％、特に好ましくは樹脂成分１００質量％に対し４０〜１５０質量％が良い。
【００６５】
また、８００ｋＡ／ｍ印加での磁気特性が保磁力（Ｈｃ）１．６〜２４ｋＡ／ｍ、飽和磁化（σｓ）５０〜２００Ａｍ²／ｋｇ、残留磁化（σｒ）２〜２０Ａｍ²／ｋｇのものが好ましい。
【００６６】
本発明に係る製造方法及び装置において、重合／蒸留装置を構成する部材のうち、重合／蒸留容器内の気相部に突出した部分を有するものとしては、撹拌機軸、邪魔板、原料投入口などのノズル類、各種センサー及びその保護管などが挙げられる。これら各部材の材質としては、ステンレス鋼、ガラス、ＦＲＰなど通常使用されるものを用いることができる。また、これらの表面は電解研磨、テフロンコーティング、グラスライニングなどの処理が施されていてもよい。
【００６７】
重合／蒸留容器内の気相部に突出した部分を有する部材の冷却方法は、その内部に二重管構造等の中空な部分を有し、該部分の内部を水やエチレングリコール等の一般的な冷却媒体を流通させることなどにより行われる。また、重合／蒸留容器内の気相部に突出した部分を有する部材が、懸濁液に接液する部分を有する場合は、該接液部分の冷却を行わないよう工夫することが、反応／蒸留工程における熱損失を最小限にする意味から好ましい。
【００６８】
上記部材を冷却するための冷却媒体の温度および流通量は、装置のスケールにより大きく異なるが、重合工程時には好ましい重合条件に外乱を与えず、蒸留工程時には蒸留効率を損なわない程度かつ、該部材表面に必要十分な量の蒸気の凝縮が得られる程度に適宜調節される。導入される冷却媒体の温度は通常−１０〜５０℃の範囲内に設定され、より好ましくは０〜４０℃の範囲内に設定される。また、冷却媒体の流量は、上記部材の冷却部への入り口温度と出口温度の差が１０℃以内、より好ましくは５℃以内となるように調節される。
【００６９】
本発明に係る重合装置に用いられる撹拌翼としては、懸濁液が滞留なく撹拌されるものならば特に限定されず、パドル翼、タービン翼、アンカー翼などの一般的な撹拌翼や市販のフルゾーン翼（神鋼パンテック社製）、マックスブレンド翼（住友重機社製）等を利用することができる。このうち、撹拌効率の点からフルゾーン翼、マックスブレンド翼が好ましく、特にフルゾーン翼が好ましく用いられる。
【００７０】
また、本発明に係る蒸留装置においても、蒸留効率の観点から撹拌装置を用いるが、その際には上記重合装置で用いられるものと同様の撹拌翼を選択することができる。
【００７１】
本発明に用いられる重合装置の好ましい一態様を図１を用いて説明する。本実施形態に係る重合装置は重合容器１、冷却可能な撹拌機軸２、撹拌翼３、冷却可能な邪魔板４、加熱ジャケット５、撹拌モーター６および冷却可能な原材料投入口７を有する。
【００７２】
符号１９は懸濁液の液面を示すが、撹拌機軸２および邪魔板４の斜線部で示す接液部には、冷却用冷媒が流通しないようになっている。
【００７３】
この重合装置には各種配管が接続しているが、その一例を示すと符号８は液排出口を示し、符号９および１０はそれぞれ加熱ジャケット用の温水もしくはスチームの入口及び出口を示し、符号１３および１５は邪魔板の冷却用冷媒の入口を示し、符号１４および１６は邪魔板の冷却用冷媒の出口を示し、符号１７及び１８はそれぞれ原材料投入口の冷却用冷媒の入口および出口を示す。
【００７４】
次に、本発明に用いられる蒸留装置の好ましい一態様を図２を用いて説明する。本実施形態に係る蒸留装置は蒸留容器２１、冷却可能な撹拌機軸２２、撹拌翼２３、冷却可能な邪魔板２４、加熱ジャケット２５、撹拌モーター２６および冷却可能な原材料投入口２７を有する。
【００７５】
符号４０は懸濁液の液面を示すが、撹拌機軸２２および邪魔板２４の斜線部で示す接液部には、冷却用接液部には、冷却用冷媒が流通しないようになっている。
【００７６】
この蒸留装置には各種配管が接続しているが、その一例を示すと符号２９は液排出口を示し、符号３０および３１はそれぞれ加熱ジャケット用の温水もしくはスチームの入り口および出口を示し、符号３２および３３はそれぞれ撹拌機軸の冷却用冷媒の入口および出口を示し、符号３４および３６は邪魔板の冷却用冷媒の入口を示し、符号３５および３７は邪魔板の冷却用冷媒の出口を示し、符号３８および３９はそれぞれ原材料投入口の冷却用冷媒の入口および出口を示す。符号２８は蒸留による留分の取り出し口を示し、必要ならばコンデンサーを接続し留分を凝縮させて取り出す。また、容器内の減圧が必要な場合は、留分の取り出し口２８を真空ポンプなどの減圧装置に接続することができる。
【００７７】
本発明により製造されるトナーは、通常一成分及び二成分系現像剤として、いずれの現像剤にも使用できる。たとえば、一成分系現像剤として、磁性体をトナー中に含有せしめた磁性トナーの場合には、現像スリーブ中に内蔵せしめたマグネットを利用し、磁性トナーを搬送及び帯電せしめる方法がある。また、磁性体を含有しない非磁性トナーを用いる場合には、ブレード及びファーブラシを用い、現像スリーブにて強制的に摩擦帯電しスリーブ上にトナーを付着させることで搬送せしめる方法がある。
【００７８】
一方、一般的に利用されている二成分系現像剤として用いる場合には、本発明のトナーと共に、キャリアを用い現像剤として使用する。本発明に使用されるキャリアとしては特に限定されるものではないが、主として、鉄、銅、亜鉛、ニッケル、コバルト、マンガン、クロム元素からなる単独及び複合フェライト状態で構成される。飽和磁化、電気抵抗を広範囲にコントロールできる点からキャリア形状も重要であり、たとえば球状、扁平、不定形などを選択し、更にキャリア表面状態の微細構造、たとえば表面凸凹性をもコントロールすることが好ましい。一般的には、上記無機酸化物を焼成・造粒することにより、あらかじめ、キャリアコア粒子を生成した後、樹脂にコーティングする方法が用いられているが、キャリアのトナーへの負荷を軽減する意味合いから、無機酸化物と樹脂を混練後、粉砕・分級して低密度分散キャリアを得る方法や、さらには、直接無機酸化物とモノマーとの混練物を水系媒体中にて懸濁重合せしめ真球状分散キャリアを得る重合キャリアを得る方法なども利用することが可能である。
【００７９】
上記キャリアの表面を樹脂等で被覆する系は、特に好ましい。その方法としては、樹脂等の被覆材を溶剤中に溶解もしくは懸濁せしめて塗布しキャリアに付着せしめる方法、単に粉体で混合する方法等、従来公知の方法がいずれも適用できる。
【００８０】
キャリア表面への固着物質としてはトナー材料により異なるが、例えばポリテトラフルオロエチレン、モノクロロトリフルオロエチレン重合体、ポリフッ化ビニリデン、シリコーン樹脂、ポリエステル樹脂、ジターシャーリーブチルサリチル酸の金属化合物、スチレン系樹脂、アクリル系樹脂、ポリアミド、ポリビニルブチラール、ニグロシン、アミノアクリレート樹脂、塩基性染料及びそのレーキ、シリカ微粉末、アルミナ微粉末などを単独或は複数で用いるのが適当であるが、必ずしもこれに制約されない。
【００８１】
上記化合物の処理量は、一般には総量でキャリア１００質量％に対し０．１〜３０質量％、好ましくは０．５〜２０質量％である。
【００８２】
これらキャリアの平均粒径は１０〜１００μｍ、好ましくは２０〜５０μｍを有することが好ましい。
【００８３】
該キャリアの特に好ましい様態としては、Ｃｕ−Ｚｎ−Ｆｅの３元系のフェライトであり、その表面をフッ素系樹脂とスチレン系樹脂の如き樹脂の組み合せ、例えばポリフッ化ビニリデンとスチレン−メチルメタクリレート樹脂；ポリテトラフルオロエチレンとスチレン−メチルメタクリレート樹脂、フッ素系共重合体とスチレン系共重合体；などを９０：１０〜２０：８０、好ましくは７０：３０〜３０：７０の比率の混合物としたもので、０．０１〜５質量％、好ましくは０．１〜１質量％コーティングし、２５０メッシュパス・１００メッシュオンのキャリア粒子が７０質量％以上ある上記平均粒径を有するコートフェライトキャリアであるものが挙げられる。該フッ素系共重合体としてはフッ化ビニリデン−テトラフルオロエチレン共重合体（１０：９０〜９０：１０）が例示され、スチレン系共重合体としてはスチレン−アクリル酸２−エチルヘキシル（２０：８０〜８０：２０）、スチレン−アクリル酸２−エチルヘキシル−メタクリル酸メチル（２０〜６０：５〜３０：１０〜５０）が例示される。
【００８４】
上記コートフェライトキャリアは粒径分布がシャープであり、本発明のトナーに対し好ましい摩擦帯電性が得られ、さらに電子写真特性を向上させる効果がある。
【００８５】
本発明におけるトナーと混合して二成分現像剤を調製する場合、その混合比率は現像剤中のトナー濃度として、２質量％〜１５質量％、好ましくは４質量％〜１３質量％にすると通常良好な結果が得られる。トナー濃度が２質量％未満では画像濃度が低く実用不可となり、１５質量％を超えるとカブリや機内飛散を増加せしめ、現像剤の耐用寿命を短める。さらに、該キャリアの磁性特性は以下のものが良い。磁気的に飽和させた後の８０ｋＡ／ｍにおける磁化の強さは３０乃至３００Ａｍ²／ｋｇであることが必要である。さらに高画質化を達成するために、好ましくは１００乃至２５０Ａｍ²／ｋｇであることがよい。３００Ａｍ²／ｋｇより大きい場合には、高画質なトナー画像が得られにくくなる。３０Ａｍ²／ｋｇ未満であると、磁気的な拘束力も減少するためにキャリア付着を生じやすい。
【００８６】
【実施例】
以下、本発明を実施例および比較例により具体的に説明するが、本発明はこれらによってなんら限定されるものではない。
【００８７】
本発明で用いた各測定方法について以下に述べる。
【００８８】
（１）粒度分布および体積平均粒径の測定
１％塩化ナトリウム水溶液１００〜１５０ｍｌ中に界面活性剤として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０．５〜５０ｍｇ加えた。この溶液を、超音波分散機で約１〜３分間分散処理を行ったのち、コールターマルチサイザー（コールター社製）により、１００μｍアパチャーを用いて２〜４０μｍの粒子の粒度分布を測定し、体積平均分布、個数平均分布を求め、これより体積平均粒径を得た。
【００８９】
（２）画質
得られたトナー粒子に対して、ＢＥＴ法による比表面積が２００ｍ²／ｇである疎水性シリカを０．７質量％となるよう外添した。この外添されたトナーが８質量％となるように、アクリル樹脂でコートされたフェライトキャリアを混合し、二成分系現像剤を得た。この現像剤を変動のない環境下において、キヤノン製フルカラー複写機ＣＬＣ５００の改造機を用いて連続通紙による画出し耐久試験を行い、目視にて画像濃度の変動やムラ等を評価した。
【００９０】
（３）カブリの測定
カブリの測定は、ＲＥＦＬＥＣＴＯＭＥＴＥＲ ＭＯＤＥＬ ＴＣ−６ＤＳ（東京電色社製）を使用して測定し、下記式より算出した。数値が小さいほど、カブリが少ない。
【００９１】
カブリ（反射率）（％）＝標準紙の反射率（％）−サンプルの非画像部の反射率（％）
【００９２】
（４）トナーの摩擦帯電量の測定
トナーの摩擦帯電量は、変動のない環境下にトナー及びキャリアを一昼夜放置した後、ブローオフ法に基づき、次の要領で摩擦帯電量を測定した。
【００９３】
図３はトナーの摩擦帯電量を測定する装置の説明図である。先ず、底に５００メッシュのスクリーン５３のある金属製の測定容器５２に摩擦帯電量を測定しようとするトナーとキャリアの質量比８：９２の混合物を５０〜１００ｍｌ容量のポリエチレン製のビンに入れ、２００回手で振盪し、該混合物（現像剤）約０．２ｇを入れ金属製のフタ５４をする。このときの測定容器５２全体の質量を秤り、Ｗ₁（ｇ）とする。次に、吸引機５１（測定容器５２と接する部分は少なくとも絶縁体）において、吸引口５７から吸引し風量調節弁５６を調整して真空計５５の圧力を２４５０Ｐａとする。この状態で充分、好ましくは２分間吸引を行いトナーを吸引除去する。このときの電位計５９が示した電位の最高値をＶ（ボルト）とする。ここで５８はコンデンサーであり容量をＣ（μＦ）とする。また、吸引後の測定容器全体の重量を秤りＷ₂（ｇ）とする。このトナーの摩擦帯電量（ｍＣ／ｋｇ）は下式の如く計算される。
【００９４】
摩擦帯電量（ｍＣ／ｋｇ）＝Ｃ×Ｖ÷（Ｗ₁−Ｗ₂）
【００９５】
（５）不定形トナーの存在率
走査型電子顕微鏡を用いトナーを観察し、不定形トナーの存在率を算出した。不定形トナーの存在率（％）は下式のごとく計算される。
【００９６】
不定形トナー存在率（％）＝不定形トナーの個数÷全トナーの個数×１００
【００９７】
実施例１
下記のようにして、水系分散媒及び重合性単量体組成物をおのおの調製した。
【００９８】
（水系分散媒の調製）
内容積１６０リットルの容器中で、下記の成分を混合し、６０℃に加温した後、高速回転剪断撹拌機クレアミックス（エム・テクニック（株）製）を用いて回転数６０００回転／分で撹拌した。
・水 ９８．４質量％
・Ｎａ₃ＰＯ₄ １．０質量％
【００９９】
次に、容器内を窒素置換すると共に、これにＣａＣｌ₂を０．６質量％添加して反応させ、Ｃａ₃（ＰＯ₄）₂の微粒子を含む水系分散媒を得た。
【０１００】
（重合性単量体組成物の調製）
・スチレン単量体 ６３．９質量％
・ｎ−ブチルアクリレート単量体 １３．１質量％
・キナクリドン系顔料 ６．２質量％
・テレフタル酸−プロピレンオキサイド変性ビスフェノールＡ ３．９質量％
・ジビニルベンセン ０．２質量％
・ジ−ｔｅｒｔ−ブチルサリチル酸アルミニウム化合物 ０．８質量％
・エステルワックス（離型剤Ｎｏ．５） ９．６質量％
上記した成分のうちスチレン単量体の一部、キナクリドン系顔料、ジ−ｔｅｒｔ−ブチルサリチル酸アルミニウム化合物を混合し、ハンディミル（三井鉱山（株）製）を用い５時間分散させた後、スチレン単量体の残部、その他の組成物を加えて６０℃に加温して十分に相溶するまで混合した。その後、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）２．３質量％を添加して重合性単量体組成物とした。
【０１０１】
上記の重合性単量体組成物を、あらかじめ調製した水系分散媒中に投入して、クレアミックスの回転数を６０００回転／分とし１０分間撹拌し造粒を行った。
【０１０２】
（重合工程）
上記の工程で造粒した懸濁液を図１に示す重合装置に導入し、撹拌翼の回転数８０回転／分、液温６０℃で重合を行った。５時間経過後、重合温度を８０℃に昇温し、加熱撹拌をさらに３時間継続して重合を完了させた。重合工程の間中、撹拌機軸および邪魔板には入り口温度１４．５℃の冷却水を導入し、重合時の液温が６０℃の場合には３リットル／分、８０℃の場合には６．５リットル／分の流量で気相部にのみ流通させ冷却を行った。
【０１０３】
（トナー及び付着状況の評価）
重合装置中の懸濁液が降温した後、重合装置より懸濁液を排出させ、これに希塩酸を添加してトナー粒子表面に固着した分散剤を溶解し、固液分離後、水洗、ろ過、乾燥することにより重合トナー粒子を得た。不定形トナーの存在率は０．２％であった。トナー粒子の粒度分布を測定したところ、体積平均粒径は８．１μｍで、粒度分布もシャープであり、摩擦帯電量は−４０ｍＣ／ｋｇと高い値を示した。また、懸濁液排出後の重合容器内を調べたところ、撹拌機軸および邪魔板表面に乾燥質量で合計１５．６ｇのスケール状付着物が生成していたが、付着物の除去を行わずに繰り返しトナーの製造を行っても、全く問題ないレベルであった。
【０１０４】
次に、得られたトナー粒子に疎水性シリカを外添し、アクリル樹脂で被覆したフェライトキャリアを混合して二成分系の現像剤とした。２００００枚の画出し試験を行ったところ、カブリは０．３％で終始画像濃度に変動もムラもなく、鮮明且つ定着性の優れた画像が安定して得られた。
【０１０５】
比較例１
重合工程中に撹拌機軸および邪魔板に冷却水を流通させないこと以外は、実施例１と全く同様にしてトナーを得た。不定形トナーの存在率は３．４％であった。トナー粒子の粒度分布を測定したところ、体積平均粒径は８．６μｍで、粒度分布は実施例１とほぼ同様であった。摩擦帯電量は−３５ｍＣ／ｋｇであった。スケール状付着物の量は乾燥質量で合計７５．３ｇであり、一部剥離して脱落しており、付着物除去を行わないと繰り返し製造ができない状況であった。
【０１０６】
次に、実施例１と同様に２００００枚の画出し試験を行ったところ、カブリは１．０％で初期には画像濃度に変動もムラもなく、安定した画像が得られたが、後半に白い筋やムラが発生した。
【０１０７】
参考例
重合工程までを実施例１と全く同様に行った後に、重合装置から懸濁液を排出させ、これを図２に示す蒸留装置に導入し、撹拌翼の回転数１００回転／分、液温８０℃、蒸留容器内圧力４９．３ｋＰａ（絶対圧）で５時間蒸留を行った。蒸留工程の間中、撹拌機軸および邪魔板には入り口温度１４．５℃の冷却水を導入し、６．５リットル／分の流量で流通させた。蒸留工程終了後、トナーの評価を行ったところ、不定形トナーの存在率は０．３％であった。トナー粒子の粒度分布を測定したところ、体積平均粒径は８．３μｍで、粒度分布は実施例１とほぼ同様であった。摩擦帯電量は−４２ｍＣ／ｋｇであった。蒸留工程におけるスケール状付着物の量は乾燥質量で合計１９．５ｇであり、付着物の除去を行わずに繰り返しトナーの製造を行っても、問題ないレベルであった。
【０１０８】
次に、実施例１と同様に２００００枚の画出し試験を行ったところ、カブリは０．５％で終始画像濃度に変動もムラもなく、鮮明且つ定着性の優れた画像が安定して得られた。
【０１１１】
【発明の効果】
本発明によれば、懸濁重合法によるトナーの製造工程において、重合／蒸留装置を構成する部材のうち、重合／蒸留容器の気相部に突出した部分上に、スケール状付着物が生成するのを抑制することができる。該付着物が剥離し、通常の粒径が揃った球形のトナーに混入すると、不定形トナーとなり、トナーの性能を低下させるが、本発明によれば、該付着物の生成が著しく減少するため、その除去作業が本質的に不要になり、かつ画像形成を行った際に、画像濃度に変動もムラもなく、鮮明且つ定着性の優れた画像が安定して得られるトナーを得ることができる。
【０１１２】
また、本発明によれば、懸濁重合法によるトナーの製造工程において、重合／蒸留装置を構成する部材のうち、重合／蒸留容器の気相部に突出した部分へのスケール状付着物の生成を抑制することができる重合／蒸留装置が提供される。
【図面の簡単な説明】
【図１】本発明に係る重合装置の一実施形態を示す概略図である。
【図２】本発明に係る蒸留装置の一実施形態を示す概略図である。
【図３】トナーの摩擦帯電量を測定する装置の説明図である。
【符号の説明】
１ 重合容器
２，２２ 撹拌機軸
３，２３ 撹拌翼
４，２４ 邪魔板
５，２５ 加熱ジャケット
６，２６ 撹拌モーター
７，２７ 原料投入口
１１，３２ 撹拌機軸の冷却用冷媒の入口
１２，３３ 撹拌機軸の冷却用冷媒の出口
１３，１５，３４，３６ 邪魔板の冷却用冷媒の入口
１４，１６，３５，３７ 邪魔板の冷却用冷媒の出口
１７，３８ 原料投入口の冷却用冷媒の入口
１８，３９ 原料投入口の冷却用冷媒の出口
１９，４０ 液面
２１ 蒸留容器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polymerized toner by a polymerization method used in electrophotography, electrostatic recording, magnetic recording, toner jet recording and the like. The present invention also relates to a production apparatus for producing such a polymerized toner.
[0002]
[Prior art]
Conventionally, many electrophotographic methods are known as described in U.S. Pat. No. 2,297,691, Japanese Patent Publication Nos. 42-23910 and 43-24748, and the like. In general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the latent image is developed with toner, and the toner is applied to a transfer material such as paper as necessary. After the image is transferred, the image is fixed by heat or pressure to obtain a copy image. Various methods have been proposed in the past for developing using toner or fixing a toner image.
[0003]
The toner is required to have excellent fluidity and stable triboelectric chargeability, and to be capable of high-quality printing without causing fogging on the photoreceptor or a decrease in image density over a long period of time. If the toner fluidity is poor, the developer will be poorly supplied and the image will be blurred or the image density will be reduced. In addition, a cleaning failure occurs, and the developer remains on the photoreceptor, causing fogging or filming with toner. When a toner film is formed on the photoreceptor, white spots and black stains are generated on the image, and the image quality is deteriorated.
[0004]
In order for the toner to exhibit excellent fluidity and form a high-quality image, it is desirable that the toner has a spherical shape and a small particle size distribution.
[0005]
Conventionally, a toner used for these purposes is generally produced as a toner having a desired particle size by a fine pulverizer and a classifier after melt-mixing a colorant composed of a dye / pigment in a thermoplastic resin and uniformly dispersing it. I came.
[0006]
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. In order for a toner to exhibit satisfactory development characteristics, its particle size distribution must be somewhat narrow. Therefore, it is necessary to classify particles obtained by pulverization to remove coarse particles and fine particles. Therefore, in the pulverization method, the yield is poor and the toner yield is low.
[0007]
Furthermore, such a highly brittle material is susceptible to further pulverization or pulverization when used for development of a copying machine or the like, and adversely affects the developability.
[0008]
Also, with this method, it is difficult to completely disperse solid fine particles such as a colorant in the resin. Depending on the degree of dispersion, an increase in fog, a decrease in image density, color mixing, and transparency Sufficient attention must be paid to the dispersion of the colorant as this can cause defects. Further, exposure of the colorant to the fracture surface of the pulverized particles may cause a change in development characteristics. Also, with the pulverization method, it is difficult to produce a spherical toner with a uniform surface, and it is difficult to obtain a toner that is satisfactory in terms of fluidity and triboelectric charging.
[0009]
In addition, in the toner by these pulverization methods, there is a restriction when adding a releasing material such as wax. That is, in order to achieve a sufficient level of dispersibility of the releasable substance, (1) it is necessary to maintain a certain level of viscosity at the kneading temperature with the resin, and (2) the content of the releasable substance is reduced. For example, about 5% by mass or less. Due to such restrictions, there is a limit to the toner fixability by the pulverization method.
[0010]
In order to overcome the problems of the toner by the pulverization method, various polymerization method toners such as suspension polymerization method toners disclosed in Japanese Patent Publication Nos. 36-10231, 43-10799, and 51-14895 are disclosed. The manufacturing method has been proposed. For example, in a suspension polymerization toner, 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. Then, 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, and a toner having a desired particle size. Get particles. Since this method does not include any pulverization step, the toner does not need to be brittle, a soft material can be used as the resin, and there is no exposure of the colorant to the particle surface, which is uniform. There is an advantage of having triboelectric chargeability. Further, since the particle size distribution of the obtained toner is relatively sharp, even if the classification step is omitted or classified, the toner can be obtained in a high yield. Further, according to this method, in addition to the restriction imposed on the above-mentioned pulverized toner, the wax can be surely included, and good fixing properties and offset resistance can be obtained. The polymerized toner obtained by this method is spherical and has a uniform surface and exhibits good development characteristics.
[0011]
As described above, the polymerization toner by suspension polymerization generally has a uniform shape close to a sphere, so that the fluidity and transferability are good, and stress is applied to the toner even after many continuous developments. There are few features and the occurrence of filming on the photoreceptor is small.
[0012]
However, when the polymerization toner is closely observed, it has been found that there is a slight amount of colorless toner (hereinafter referred to as “amorphous toner”) containing no irregular shape or colorant. Amorphous toners are considered to be produced in a different process from normal polymerized toners. If this ratio is increased, toner characteristics such as triboelectric chargeability and development characteristics when image evaluations are adversely affected, image density fluctuations, whiteness Generation of streaks and fog is observed. Therefore, in the production method of the polymerized toner, preventing the generation of the irregular shaped toner is an important matter not only on the properties of the toner but also on the production cost.
[0013]
[Problems to be solved by the invention]
The present inventors paid attention to the polymerization process and the distillation process as the cause of the formation of the irregular toner in the above-described polymerization toner, and examined in detail the phenomenon that occurs during both processes. During the polymerization process and during the distillation process, the members constituting the polymerization apparatus and the distillation apparatus, that is, the stirrer shaft, baffle plate, various sensors, and protective tubes thereof, protruded into the gas phase portion of the polymerization container and the distillation container. It was discovered that scale-like deposits were formed in the portion, and it was found that there was a correlation between the amount of the scale-like deposits and the proportion of the irregular shaped toner in the polymerization toner obtained. This scale-like deposit is mixed by peeling and is observed as an irregular shaped toner.
[0014]
The production process of the scale-like deposit is considered as follows.
(1). Unreacted polymerizable monomer vapor condenses on the surface of the member protruding into the gas phase part in the container, and is heated in the gas phase part to polymerize, resulting in a composition different from the normal polymerization reaction in the liquid phase. The in-process polymer is formed and deposited / deposited.
(2). Due to the splashing or foaming of the suspension polymerization reaction solution, the suspension polymer fine particles adhere to the surface of the member protruding into the gas phase portion in the container and are dried / solidified by heat. When the surface temperature of the incidental device is higher than the glass transition temperature of the polymer produced by polymerization of the polymerizable monomer, fusion occurs and adhesion becomes strong.
(3). The above (1) and (2) occur in combination.
[0015]
In addition, if the scale-like deposit grows to a sufficient size and peels / drops out in the course of the study, it may cause clogging or sticking in piping or valves connected to the polymerization vessel or distillation vessel. Turned out to be. This is not preferable because it requires frequent removal work of scale-like deposits, leading to a decrease in the operating rate of the manufacturing apparatus, resulting in an increase in the cost of the product toner.
[0016]
Therefore, the object of the present invention is to generate scale-like deposits on the surface of the polymerization vessel and the portion of the distillation vessel that protrudes from the vapor phase portion of the polymerization vessel and distillation device in the polymerization step and distillation step. It is an object of the present invention to provide a method for producing a polymerized toner that is not caused to occur, and a polymerization apparatus and a distillation apparatus that realize the method.
[0017]
[Means for Solving the Problems]
As a result of intensive studies to suppress the formation of scale-like deposits in the polymerization and distillation steps, the present inventors have determined that the polymerization vessel and the vapor phase portion of the distillation vessel among the members constituting the polymerization device and the distillation device. It has been found that the following effects can be obtained by cooling the protruding portion.
(1). The polymerization rate of the unreacted monomer condensed on the surface of the member is reduced, and the production of a polymer having a composition different from that of the normal polymerization reaction and the production process is suppressed.
(2). Suspension polymer fine particles adhering to the surface of the member due to splashing or foaming of the suspension polymerization reaction solution are prevented from drying / coagulating by heat.
(3). The amount of vapor condensing on the surface of the member is increased, and the condensate always flows down the surface and keeps it wet, thereby obtaining an adhesion preventing / cleaning effect.
[0018]
Based on the above knowledge, the present inventors have completed the present invention.
[0019]
  That is, the present invention provides a polymerizable monomer composition having at least a polymerizable monomer, a colorant, a release agent, and a crosslinking agent.Contains dispersantIt is obtained by granulating in an aqueous dispersion medium to form particles of a polymerizable monomer composition, and polymerizing the polymerizable monomer in the particles of the polymerizable monomer composition in the aqueous dispersion medium. In a method for producing a polymerized toner having colored polymerized toner particles,
  The polymerization apparatus in which the polymerization is performed has a polymerization vessel, a stirrer shaft having a stirring blade, and a baffle plate,
  In the polymerization vessel, a liquid phase part of an aqueous dispersion medium having particles of a polymerizable monomer composition and a gas phase part are formed,
  During the polymerization of the polymerizable monomer at a polymerization temperature of 50 to 90 ° C., the surface of the portion protruding from the gas phase portion of the stirrer shaft in the polymerization vessel is placed inside the stirrer shaft.Temperature 0-40 ° CCool by circulating the cooling medium,and,The surface of the portion of the baffle plate protruding into the gas phase portion in the polymerization vessel is placed inside the baffle plate.Temperature 0-40 ° CCool by circulating a cooling mediumThis suppresses the formation of scale-like deposits on the stirrer shaft and the baffle plate
The present invention relates to a method for producing a polymerized toner.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0024]
As a method for producing the polymerized toner of the present invention, a release agent, a colorant, a charge control agent, a polymerization initiator, a crosslinking agent and other additives are added to a polymerizable monomer, and a homogenizer or an ultrasonic disperser is used. A monomer composition uniformly dissolved or dispersed by a normal stirrer is dispersed in a water phase containing a dispersion stabilizer by a stirrer having a high shearing force such as Claremix or a homomixer. Granulation is performed by adjusting the stirring speed / time so that the droplets of the composition have the desired toner particle size. In the suspension polymerization method, it is usually preferable to use 100 to 3000% by mass of water as a dispersion medium with respect to 100% by mass of the monomer system. After that, since the particle state is maintained by the action of the dispersion stabilizer, stirring may be performed to such an extent that the sedimentation of the particles is prevented. Polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. Further, the temperature may be raised in the latter half of the polymerization reaction for the purpose of obtaining a desired molecular weight distribution. Further, in order to remove unreacted polymerizable monomers, by-products, etc. The partial aqueous medium may be distilled off by distillation. After completion of the reaction, the produced toner particles are recovered by washing and filtration and dried.
[0025]
As the polymerizable monomer used in the toner of the present invention, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used. Monofunctional polymerizable monomers include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butyl. Styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate , Acrylic polymerizable monomers such as n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl Methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylic polymerizable monomers such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; vinyl methyl ether Vinyl ether such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.
[0026]
As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol Diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol Dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4- (methacryloxy-diethoxy) phenyl) propane, Examples include 2,2′-bis (4- (methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.
[0027]
In the present invention, the above monofunctional polymerizable monomers are used alone or in combination of two or more, or the above monofunctional polymerizable monomers and polyfunctional polymerizable monomers are used in combination. To do. Among the above-mentioned monomers, styrene or a styrene derivative is preferably used alone or in combination or in combination with other monomers from the viewpoint of toner development characteristics and durability.
[0028]
Examples of the colorant used in the present invention include carbon black, iron black, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as Basic Green 6; yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa Yellow G, permanent yellow NCG, tartrazine lake, molybdenum orange, permanent orange GTR, benzidine orange G, cadmium Red, Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Bitumen, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green And pigments such as B, malachite green lake, and final yellow green G.
[0029]
In the present invention in which polymerization is carried out in an aqueous dispersion medium, it is necessary to pay attention to the polymerization inhibitory property and water phase transferability of the colorant, preferably surface modification, for example, a hydrophobic treatment with a substance that does not inhibit polymerization It is better to have applied. In particular, dyes and carbon blacks have many polymerization inhibiting properties, so care must be taken when using them. A preferable method for surface-treating the dye system includes a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance, and the obtained colored polymer is added to the monomer system. In addition to carbon black, the carbon black may be grafted with a substance that reacts with the surface functional group of the carbon black, such as polyorganosiloxane. In the present invention, a magnetic substance may be added, but this is also preferably used after being subjected to a surface treatment.
[0030]
As the release agent, a wax in a solid state at room temperature is preferable, and a solid wax having a melting point of 40 to 100 ° C. is particularly preferable in terms of toner blocking resistance, durability of a large number of sheets, low-temperature fixability, and offset resistance.
[0031]
Examples of the wax include paraffin wax, polyolefin wax, microcrystalline wax, polymethylene wax such as Fischer-Tropsch wax, amide wax, higher fatty acid, long chain alcohol, ester wax, and derivatives thereof such as graft compounds and block compounds. These preferably have a sharp maximum endothermic peak in the DSC endothermic curve from which low molecular weight components have been removed.
[0032]
Examples of the wax preferably used include linear alkyl alcohols having 15 to 100 carbon atoms, linear fatty acids, linear acid amides, linear esters, and montan derivatives. Those from which impurities such as liquid fatty acids have been previously removed from these waxes are also preferred.
[0033]
Further, the wax preferably used is a low molecular weight alkylene polymer obtained by polymerizing alkylene with radical polymerization under high pressure or Ziegler catalyst or other catalyst under low pressure; alkylene obtained by thermally decomposing high molecular weight alkylene polymer Polymer: A low molecular weight alkylene polymer produced as a by-product in the polymerization of alkylene, separated and purified; a hydrocarbon polymer distillation residue obtained from a synthesis gas composed of carbon monoxide and hydrogen by the age method, or a distillation residue Examples include polymethylene wax obtained by extracting and fractionating specific components from a synthetic hydrocarbon obtained by hydrogenation. These waxes may contain an antioxidant.
[0034]
In order to improve the translucency of the fixed image, a solid ester wax is preferable, and the solid ester wax having a melting point of 40 to 100 ° C. is particularly preferable.
[0035]
The ester wax used in the present invention is formed from a compound represented by the following general formulas (I) to (VI) and has a melting point of 40 to 100 ° C.
[0036]
[Chemical 1]

(Wherein, a and b are integers from 0 to 4, and a + b is 4. R₁And R₂Is an organic group having 1 to 40 carbon atoms, R₁And R₂And the carbon number difference is 3 or more. m and n are integers of 0 to 25, and m and n are not 0 at the same time. )
[0037]
[Chemical 2]

(In the formula, a and b are integers of 0 to 3, and a + b is 1 to 3. R₁And R₂Is an organic group having 1 to 40 carbon atoms, R₁And R₂And the carbon number difference is 3 or more. R_ThreeIs a hydrogen atom or an organic group having 1 or more carbon atoms. However, when a + b = 2, R_ThreeOne of these is an organic group having 1 or more carbon atoms. k is an integer of 1 to 3. m and n are integers of 0 to 25, and m and n are not 0 at the same time. )
[0038]
[Chemical Formula 3]

(Wherein R₁And R_ThreeIs an organic group having 6 to 32 carbon atoms, R₁And R_ThreeMay or may not be the same. R₂Represents an organic group having 1 to 20 carbon atoms. )
[0039]
[Formula 4]

(Wherein R₁And R₂Is an organic group having 6 to 32 carbon atoms, R₁And R_ThreeMay or may not be the same.
R₂Is -CH₂CH₂OC₆H_FourOCH₂CH₂−,

[0040]
[Chemical formula 5]

(In the formula, a is an integer of 0 to 4, b is an integer of 1 to 4, and a + b is 4.₁Is an organic group having 1 to 40 carbon atoms. m and n are integers of 0 to 25, and m and n are not 0 at the same time. )
[0041]
[Chemical 6]

(Wherein R₁And R₂Denote the same or different hydrocarbon groups having 15 to 45 carbon atoms. )
[0042]
The melting point of the ester wax is preferably 40 to 100 ° C. When the melting point is less than 40 ° C., the toner has insufficient blocking resistance and shape retention, and when it exceeds 100 ° C., the releasing effect becomes insufficient. The following are illustrated as an ester wax as a mold release agent which consists of ester compounds.
[0043]
[Chemical 7]

[0044]
[Chemical 8]

[0045]
When the releasing agent is an ester wax having an ester compound having the above structural formula, it exhibits good transparency and exhibits good fixability when incorporated in toner particles.
[0046]
Further, in the present invention, the release agent is blended in an amount of 5 to 40% by mass (more preferably 10 to 30% by mass) with respect to 100% by mass of the polymerizable monomer. The release agent may be contained in the toner particles in an amount of 5 to 40% by mass (more preferably 10 to 30% by mass) per 100% by mass of the produced binder resin.
[0047]
The toner of the present invention may contain a charge control agent.
[0048]
Known charge control agents can be used. For example, organometallic compounds and chelate compounds are effective for controlling the toner to be negatively charged, and monoazo metal compounds, acetylacetone metal compounds, aromatic hydroxycarboxylic compounds are effective. There are metal compounds of acids and aromatic dicarboxylic acids. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and metal salts thereof, anhydrides, esters, and phenol derivatives such as bisphenol.
[0049]
Further, urea derivatives, metal-containing salicylic acid compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylic sulfonic acid copolymers, nonmetal carboxylic acids System compounds and the like.
[0050]
Examples of toners that are controlled to be positively charged include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, And onium salts such as phosphonium salts thereof and their lake pigments, triphenylmethane dyes and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid) , Lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids; siorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate Dioctyl tin borate, shea organo tin borate such as dicyclohexyl tin borate; can be used in combination of these alone, or two or more kinds. Among these, a charge control agent such as a nigrosine-type quaternary ammonium salt is particularly preferably used.
[0051]
These charge control agents may be used in an amount of 0.01 to 20% by mass (more preferably 0.5 to 10% by mass) with respect to 100% by mass of the resin component.
[0052]
In the case of a color toner, a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount is particularly preferable. Furthermore, in the case of a toner obtained by a polymerization method, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous system is particularly preferable.
[0053]
As a polymerization initiator required when polymerizing a polymerizable monomer, for example, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1, Azo polymerization initiators such as 1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone Peroxide-based polymerization initiators such as peroxide, t-butylperoxy-2-ethylhexanoate, diisopropylperoxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide are used. The addition amount of the polymerization initiator varies depending on the target degree of polymerization, but generally 0.5 to 20% by mass is added to the monomer. The kind of the initiator is slightly different depending on the polymerization method, but can be used alone or mixed with reference to the 10-hour half-life temperature.
[0054]
Examples of the crosslinking agent include polyfunctional compounds such as divinylbenzene, 4,4′-divinylbiphenyl, ethylene glycol di (meth) acrylate, glycidyl (meth) acrylate, and trimethylolpropane tri (meth) acrylate. it can.
[0055]
Further, as a dispersion stabilizer for satisfactorily dispersing the polymerizable monomer composition in an aqueous medium, for example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, carbonic acid which are inorganic oxides. Calcium, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic substance, ferrite and the like can be mentioned. As the organic compound, for example, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, starch and the like are used dispersed in an aqueous phase. These dispersion stabilizers are preferably used in an amount of 0.2 to 10.0% by mass with respect to 100% by mass of the polymerizable monomer.
[0056]
Commercially available dispersion stabilizers may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, the inorganic compound can be generated in a dispersion medium under high-speed stirring. . For example, in the case of tricalcium phosphate, a dispersant preferable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring. Moreover, you may use together 0.001-0.1 mass% surfactant for refinement | miniaturization of these dispersing agents. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, such as sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, olein. Acid calcium or the like is preferably used.
[0057]
In the case of a polymerization method using an aqueous dispersion medium such as suspension polymerization, the inclusion of a release agent can be promoted by adding a polar resin to the polymerizable monomer composition. When a polar resin is present in the polymerizable monomer composition in the aqueous medium, the polar resin moves to the vicinity of the interface between the aqueous medium and the polymerizable monomer composition due to the difference in hydrophilicity. Resin is unevenly distributed. As a result, the toner particles have a capsule structure, and even when a large amount of the release agent is contained, the encapsulation property of the release agent is improved.
[0058]
The polar resin is particularly preferably a polyester-based resin since the fluidity of the polar resin itself can be expected when unevenly distributed on the toner surface.
[0059]
Examples of polar resins that can be used in the toner of the present invention include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, Acid component monomers such as sebacic acid, camphoric acid, cyclohexanedicarboxylic acid, trimellitic acid; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4 -Butanediol, neopentyl glycol, alkylene glycols such as 1,4-bis (hydroxymethyl) cyclohexane and polyalkylene glycols, bisphenol A, hydrogenated bisphenol, ethylene oxide adduct of bisphenol A, bisphenol A B pyrene oxide adducts, glycerol, trimethylolpropane, and such polyhydric alcohols monomer pentaerythritol may be mentioned those condensation polymerization.
[0060]
In using the toner produced according to the present invention, an external additive can be used for the purpose of imparting various properties. The external additive preferably has a particle size of 1/10 or less of the weight average diameter of the toner particles from the viewpoint of durability when added to the toner. The particle size of the additive means the average particle size obtained by observing the surface of the toner particles with an electron microscope. As the external additive, for example, the following are used.
[0061]
Metal oxide (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitride (silicon nitride, etc.), carbide (silicon carbide, etc.), metal salt (sulfuric acid) Calcium, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica, etc.
[0062]
These external additives are used in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight, based on 100% by weight of toner particles. These external additives may be used alone or in combination. Those subjected to hydrophobic treatment are more preferable.
[0063]
Furthermore, the toner of the present invention can be used as a magnetic toner containing a magnetic material. In this case, the magnetic material can also serve as a colorant. In the present invention, the magnetic material contained in the magnetic toner includes iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, nickel, or aluminum, cobalt, copper, lead, magnesium of these metals, Examples thereof include alloys of metals such as tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.
[0064]
These ferromagnetic materials have an average particle size of 2 μm or less, preferably about 0.1 to 0.5 μm. The amount to be contained in the toner is about 20 to 200% by mass with respect to 100% by mass of the resin component, and particularly preferably 40 to 150% by mass with respect to 100% by mass of the resin component.
[0065]
Further, the magnetic characteristics when 800 kA / m is applied are coercive force (Hc) of 1.6 to 24 kA / m, and saturation magnetization (σs) of 50 to 200 Am.²/ Kg, residual magnetization (σr) 2-20 Am²/ Kg is preferred.
[0066]
In the production method and apparatus according to the present invention, among the members constituting the polymerization / distillation apparatus, those having a portion protruding to the gas phase part in the polymerization / distillation vessel include a stirrer shaft, baffle plate, raw material inlet, etc. Nozzles, various sensors and protective tubes thereof. As materials of these members, those usually used such as stainless steel, glass and FRP can be used. In addition, these surfaces may be subjected to treatments such as electropolishing, Teflon coating, and glass lining.
[0067]
The method of cooling a member having a portion protruding into the gas phase portion in the polymerization / distillation vessel has a hollow portion such as a double-pipe structure inside thereof, and the inside of the portion is generally made of water, ethylene glycol or the like. For example, by circulating a cooling medium. In addition, when the member having a portion protruding into the gas phase portion in the polymerization / distillation vessel has a portion in contact with the suspension, it is possible to devise not to cool the wetted portion. This is preferable in terms of minimizing heat loss in the distillation process.
[0068]
Although the temperature and flow rate of the cooling medium for cooling the above-mentioned member greatly vary depending on the scale of the apparatus, the surface of the member does not disturb the preferred polymerization conditions during the polymerization step and does not impair the distillation efficiency during the distillation step. The amount of the vapor is appropriately adjusted so as to obtain a necessary and sufficient amount of vapor condensation. The temperature of the introduced cooling medium is usually set in the range of −10 to 50 ° C., more preferably in the range of 0 to 40 ° C. The flow rate of the cooling medium is adjusted so that the difference between the inlet temperature and the outlet temperature of the member to the cooling part is within 10 ° C, more preferably within 5 ° C.
[0069]
The stirring blade used in the polymerization apparatus according to the present invention is not particularly limited as long as the suspension is stirred without stagnation, and a general stirring blade such as a paddle blade, a turbine blade, an anchor blade, or a commercially available full zone. Wings (manufactured by Shinko Pantech Co., Ltd.), Max Blend Wings (manufactured by Sumitomo Heavy Industries, Ltd.) and the like can be used. Among these, a full zone blade and a max blend blade are preferable from the viewpoint of stirring efficiency, and a full zone blade is particularly preferably used.
[0070]
In the distillation apparatus according to the present invention, a stirring apparatus is used from the viewpoint of distillation efficiency. In this case, the same stirring blade as that used in the polymerization apparatus can be selected.
[0071]
A preferred embodiment of the polymerization apparatus used in the present invention will be described with reference to FIG. The polymerization apparatus according to this embodiment includes a polymerization vessel 1, a stirrer shaft 2 that can be cooled, a stirring blade 3, a baffle plate 4 that can be cooled, a heating jacket 5, a stirring motor 6, and a raw material inlet 7 that can be cooled.
[0072]
Reference numeral 19 indicates the liquid level of the suspension, but the cooling refrigerant does not flow through the liquid contact portion indicated by the hatched portion of the stirrer shaft 2 and the baffle plate 4.
[0073]
Various pipes are connected to this polymerization apparatus. For example, reference numeral 8 denotes a liquid outlet, reference numerals 9 and 10 denote hot water or steam inlets and outlets for the heating jacket, and reference numeral 13. Reference numerals 14 and 16 denote outlets for the cooling refrigerant for the baffle plate, and reference numerals 17 and 18 denote inlets and outlets for the cooling refrigerant at the raw material inlet, respectively.
[0074]
Next, a preferred embodiment of the distillation apparatus used in the present invention will be described with reference to FIG. The distillation apparatus according to the present embodiment includes a distillation vessel 21, a stirrer shaft 22 that can be cooled, a stirring blade 23, a baffle plate 24 that can be cooled, a heating jacket 25, a stirring motor 26, and a raw material inlet 27 that can be cooled.
[0075]
Reference numeral 40 indicates the liquid level of the suspension, but in the liquid contact portion indicated by the hatched portion of the stirrer shaft 22 and the baffle plate 24, the cooling refrigerant does not flow through the cooling liquid contact portion. .
[0076]
Various pipes are connected to this distillation apparatus. For example, reference numeral 29 denotes a liquid outlet, reference numerals 30 and 31 denote hot water or steam inlets and outlets for the heating jacket, and reference numeral 32. Reference numerals 34 and 36 respectively denote inlets and outlets for the cooling refrigerant for the baffle plate, reference numerals 35 and 37 denote outlets for the cooling refrigerant for the baffle plates, Reference numerals 38 and 39 respectively denote an inlet and an outlet for the cooling refrigerant at the raw material inlet. Reference numeral 28 denotes a distillate outlet for distillation. If necessary, a condenser is connected to condense the distillate. In addition, when decompression in the container is necessary, the fraction outlet 28 can be connected to a decompression device such as a vacuum pump.
[0077]
The toner produced according to the present invention can be used in any developer as a one-component or two-component developer. For example, in the case of a magnetic toner in which a magnetic material is contained in the toner as the one-component developer, there is a method of transporting and charging the magnetic toner using a magnet built in the developing sleeve. When non-magnetic toner containing no magnetic material is used, there is a method in which a blade and a fur brush are used to forcibly charge by a developing sleeve, and the toner is attached to the sleeve and conveyed.
[0078]
On the other hand, when used as a two-component developer that is generally used, a carrier is used as a developer together with the toner of the present invention. Although it does not specifically limit as a carrier used for this invention, It is comprised by the single and composite ferrite state which mainly consist of iron, copper, zinc, nickel, cobalt, manganese, and a chromium element. The carrier shape is also important from the viewpoint that the saturation magnetization and electric resistance can be controlled in a wide range. For example, it is preferable to select a spherical shape, a flat shape, an indeterminate shape, etc., and also to control the fine structure of the carrier surface state, for example, the surface unevenness. . In general, a method is used in which carrier core particles are formed in advance by firing and granulating the above inorganic oxide, and then coating the resin. Then, after kneading the inorganic oxide and resin, pulverizing and classifying to obtain a low-density dispersion carrier, and further, the kneaded product of the inorganic oxide and the monomer is directly suspension-polymerized in an aqueous medium to obtain a spherical shape. A method for obtaining a polymerized carrier for obtaining a dispersed carrier can also be used.
[0079]
A system in which the surface of the carrier is coated with a resin or the like is particularly preferable. As the method, any of conventionally known methods such as a method in which a coating material such as a resin is dissolved or suspended in a solvent and applied and adhered to a carrier, or a method of simply mixing with a powder can be applied.
[0080]
The substance to be fixed on the carrier surface varies depending on the toner material. For example, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butyl salicylic acid, styrene resin, acrylic It is appropriate to use a single resin or a plurality of resin, polyamide, polyvinyl butyral, nigrosine, aminoacrylate resin, basic dye and its lake, fine silica powder, fine alumina powder, etc., but is not limited thereto.
[0081]
The treatment amount of the above compound is generally 0.1 to 30% by mass, preferably 0.5 to 20% by mass with respect to 100% by mass of the carrier as a total amount.
[0082]
The average particle size of these carriers is 10 to 100 μm, preferably 20 to 50 μm.
[0083]
A particularly preferred embodiment of the carrier is Cu—Zn—Fe ternary ferrite, the surface of which is a combination of a resin such as a fluorine resin and a styrene resin, for example, polyvinylidene fluoride and a styrene-methyl methacrylate resin; Polytetrafluoroethylene and styrene-methyl methacrylate resin, fluorine copolymer and styrene copolymer; and the like in a mixture of 90:10 to 20:80, preferably 70:30 to 30:70. 0.01 to 5% by mass, preferably 0.1 to 1% by mass, and a coated ferrite carrier having the above average particle diameter in which 250 mesh pass and 100 mesh on carrier particles are 70% by mass or more. Can be mentioned. Examples of the fluorine-based copolymer include vinylidene fluoride-tetrafluoroethylene copolymer (10:90 to 90:10), and examples of the styrene-based copolymer include styrene-2-ethylhexyl acrylate (20:80 to 80:20), styrene-2-ethylhexyl acrylate-methyl methacrylate (20-60: 5-30: 10-50).
[0084]
The coated ferrite carrier has a sharp particle size distribution, provides a preferable triboelectric chargeability for the toner of the present invention, and has an effect of improving electrophotographic characteristics.
[0085]
When a two-component developer is prepared by mixing with the toner in the present invention, the mixing ratio is usually good when the toner concentration in the developer is 2% by mass to 15% by mass, preferably 4% by mass to 13% by mass. Results. If the toner concentration is less than 2% by mass, the image density is low and impractical, and if it exceeds 15% by mass, fogging and in-machine scattering are increased and the useful life of the developer is shortened. Further, the magnetic properties of the carrier are preferably as follows. The strength of magnetization at 80 kA / m after magnetic saturation is 30 to 300 Am²/ Kg is required. In order to achieve higher image quality, preferably 100 to 250 Am²/ Kg is good. 300 Am²When it is larger than / kg, it becomes difficult to obtain a high-quality toner image. 30 Am²If it is less than / kg, the magnetic binding force also decreases, so that carrier adhesion tends to occur.
[0086]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited at all by these.
[0087]
Each measurement method used in the present invention will be described below.
[0088]
(1) Measurement of particle size distribution and volume average particle size
0.1 to 5 ml of alkylbenzene sulfonate as a surfactant was added to 100 to 150 ml of 1% aqueous sodium chloride solution, and 0.5 to 50 mg of a measurement sample was further added. This solution was subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and then a particle size distribution of 2 to 40 μm particles was measured using a 100 μm aperture with a Coulter Multisizer (manufactured by Coulter Inc.). Distribution and number average distribution were obtained, and volume average particle diameter was obtained from this.
[0089]
(2) Image quality
The obtained toner particles have a specific surface area of 200 m by the BET method.²/ G of hydrophobic silica was externally added to 0.7 mass%. A ferrite carrier coated with an acrylic resin was mixed so that the externally added toner was 8% by mass to obtain a two-component developer. Under an environment in which this developer is not varied, an image endurance test by continuous paper passing was performed using a modified model of Canon full-color copying machine CLC500, and image density variation and unevenness were visually evaluated.
[0090]
(3) Measurement of fog
The fog was measured using a REFECTOMETER MODEL TC-6DS (manufactured by Tokyo Denshoku Co., Ltd.) and calculated from the following formula. The smaller the value, the less fog.
[0091]
Fog (reflectance) (%) = reflectance of standard paper (%) − reflectance of non-image part of sample (%)
[0092]
(4) Measurement of toner triboelectric charge
Regarding the triboelectric charge amount of the toner, the triboelectric charge amount was measured in the following manner based on the blow-off method after the toner and the carrier were left for a day and night in an environment where there was no fluctuation.
[0093]
FIG. 3 is an explanatory diagram of an apparatus for measuring the triboelectric charge amount of toner. First, in a metal measurement container 52 having a 500 mesh screen 53 at the bottom, a mixture of toner and carrier in a mass ratio of 8:92 to be measured for triboelectric charge is put into a polyethylene bottle having a capacity of 50 to 100 ml. Shake by hand 200 times, put about 0.2 g of the mixture (developer), and make a metal lid 54. Weigh the entire measurement container 52 at this time,₁(G). Next, in the suction device 51 (at least the insulator is in contact with the measurement container 52), the suction is performed through the suction port 57 and the air volume control valve 56 is adjusted so that the pressure of the vacuum gauge 55 is 2450Pa. In this state, the toner is removed by suction for 2 minutes. The maximum value of the potential indicated by the electrometer 59 at this time is V (volt). Here, 58 is a capacitor, and the capacity is C (μF). Also, weigh the entire measurement container after suction.₂(G). The triboelectric charge amount (mC / kg) of the toner is calculated as follows:
[0094]
Frictional charge (mC / kg) = C x V / (W₁-W₂)
[0095]
(5) Presence rate of irregular shaped toner
The toner was observed using a scanning electron microscope, and the abundance of the irregular shaped toner was calculated. The abundance (%) of the amorphous toner is calculated as follows.
[0096]
Amorphous toner abundance ratio (%) = number of irregular toners / total number of toners × 100
[0097]
Example 1
An aqueous dispersion medium and a polymerizable monomer composition were prepared as follows.
[0098]
(Preparation of aqueous dispersion medium)
In a container with an internal volume of 160 liters, the following components were mixed, heated to 60 ° C., and then rotated at 6000 rpm with a high-speed rotary shear stirrer CLEARMIX (M Technique Co., Ltd.). Stir.
・ Water 98.4% by mass
・ Na_ThreePO_Four                                              1.0% by mass
[0099]
Next, the inside of the container is purged with nitrogen, and CaCl is added thereto.₂0.6% by mass of Ca is reacted._Three(PO_Four)₂An aqueous dispersion medium containing fine particles was obtained.
[0100]
(Preparation of polymerizable monomer composition)
・ Styrene monomer 63.9% by mass
-N-butyl acrylate monomer 13.1% by mass
・ Quinacridone pigment 6.2% by mass
・ Terephthalic acid-propylene oxide modified bisphenol A 3.9% by mass
・ Divinyl benzene 0.2% by mass
・ Di-tert-butylsalicylic acid aluminum compound 0.8% by mass
Ester wax (release agent No. 5) 9.6% by mass
Among the components described above, a part of the styrene monomer, a quinacridone pigment, and an aluminum di-tert-butylsalicylate compound were mixed and dispersed for 5 hours using a handy mill (Mitsui Mining Co., Ltd.). The remainder of the polymer and other compositions were added and heated to 60 ° C. and mixed until fully compatible. Thereafter, 2.3% by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added thereto to obtain a polymerizable monomer composition.
[0101]
The above polymerizable monomer composition was put into an aqueous dispersion medium prepared in advance, and the number of revolutions of CLEARMIX was set to 6000 rpm and stirred for 10 minutes for granulation.
[0102]
(Polymerization process)
The suspension granulated in the above process was introduced into the polymerization apparatus shown in FIG. 1, and polymerization was carried out at a stirring blade speed of 80 revolutions / minute and a liquid temperature of 60 ° C. After 5 hours, the polymerization temperature was raised to 80 ° C., and heating and stirring were further continued for 3 hours to complete the polymerization. During the polymerization process, cooling water having an inlet temperature of 14.5 ° C. is introduced into the stirrer shaft and baffle plate. When the liquid temperature during polymerization is 60 ° C., it is 3 liters / min. Cooling was performed by circulating only in the gas phase at a flow rate of 5 liters / minute.
[0103]
(Evaluation of toner and adhesion status)
After the temperature of the suspension in the polymerization apparatus has dropped, the suspension is discharged from the polymerization apparatus, to which is added dilute hydrochloric acid to dissolve the dispersant fixed to the toner particle surface, and after solid-liquid separation, water washing, filtration, Polymerized toner particles were obtained by drying. The abundance of the irregular toner was 0.2%. When the particle size distribution of the toner particles was measured, the volume average particle size was 8.1 μm, the particle size distribution was sharp, and the triboelectric charge amount was as high as −40 mC / kg. Further, when the inside of the polymerization vessel after discharging the suspension was examined, a total of 15.6 g of scale-like deposits were generated on the surface of the stirrer shaft and the baffle plate, but the deposits were not removed. Even if the toner was repeatedly manufactured, it was at a level that does not cause any problem.
[0104]
Next, hydrophobic silica was externally added to the obtained toner particles, and a ferrite carrier coated with an acrylic resin was mixed to obtain a two-component developer. As a result of performing an image printing test on 20,000 sheets, the fog was 0.3%, and there was no fluctuation or unevenness in the image density from start to finish, and a clear and stable image having excellent fixability was stably obtained.
[0105]
Comparative Example 1
A toner was obtained in exactly the same manner as in Example 1 except that cooling water was not passed through the stirrer shaft and baffle plate during the polymerization process. The abundance of the irregular toner was 3.4%. When the particle size distribution of the toner particles was measured, the volume average particle size was 8.6 μm and the particle size distribution was almost the same as in Example 1. The triboelectric charge amount was -35 mC / kg. The total amount of the scale-like deposits was 75.3 g in terms of dry mass, partly peeled off and dropped, and it was impossible to repeat the production without removing the deposits.
[0106]
Next, when 20000 printout tests were performed in the same manner as in Example 1, the fog was 1.0% and there was no fluctuation or unevenness in the image density at the beginning, and a stable image was obtained. White streaks and unevenness occurred.
[0107]
  Reference example
  After the polymerization process was carried out in exactly the same way as in Example 1, the suspension was discharged from the polymerization apparatus and introduced into the distillation apparatus shown in FIG. Distillation was performed at 5 ° C. and a distillation vessel internal pressure of 49.3 kPa (absolute pressure) for 5 hours. During the distillation process, cooling water having an inlet temperature of 14.5 ° C. was introduced into the stirrer shaft and baffle plate and allowed to flow at a flow rate of 6.5 liters / minute. When the toner was evaluated after the distillation step, the abundance of the irregular shaped toner was 0.3%. When the particle size distribution of the toner particles was measured, the volume average particle size was 8.3 μm and the particle size distribution was almost the same as in Example 1. The triboelectric charge amount was -42 mC / kg. The amount of scale-like deposits in the distillation step was 19.5 g in terms of dry mass, and even if the toner was repeatedly manufactured without removing the deposits, the level was satisfactory.
[0108]
Next, when 20000 printout tests were performed in the same manner as in Example 1, the fog was 0.5%, there was no fluctuation or unevenness in the image density from start to finish, and a clear and excellent fixability image was stabilized. Obtained.
[0111]
【The invention's effect】
According to the present invention, in the toner production process by the suspension polymerization method, a scale-like deposit is generated on a portion of the member constituting the polymerization / distillation device that protrudes from the gas phase portion of the polymerization / distillation vessel. Can be suppressed. When the adhering material is peeled off and mixed with a spherical toner having a regular particle size, it becomes an irregular toner, and the performance of the toner is deteriorated. However, according to the present invention, the generation of the adhering material is remarkably reduced. Therefore, it is possible to obtain a toner in which the removal operation is essentially unnecessary, and when image formation is performed, there is no fluctuation or unevenness in the image density, and a stable and clear image with excellent fixability can be obtained. .
[0112]
Further, according to the present invention, in the toner production process by the suspension polymerization method, the formation of scale-like deposits on the portion of the polymerization / distillation apparatus that protrudes from the gas phase portion of the polymerization / distillation vessel A polymerization / distillation apparatus capable of suppressing the above is provided.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a polymerization apparatus according to the present invention.
FIG. 2 is a schematic view showing an embodiment of a distillation apparatus according to the present invention.
FIG. 3 is an explanatory diagram of an apparatus for measuring the triboelectric charge amount of toner.
[Explanation of symbols]
1 Polymerization vessel
2,22 Agitator shaft
3,23 stirring blade
4,24 baffle plate
5,25 Heating jacket
6,26 Stirring motor
7,27 Raw material inlet
11, 32 Coolant refrigerant inlet of the agitator shaft
12,33 Stirrer shaft cooling refrigerant outlet
13, 15, 34, 36 Coolant inlet for cooling baffle plate
14, 16, 35, 37 Outlet of refrigerant for cooling baffle plate
17,38 Cooling refrigerant inlet at raw material inlet
18, 39 Cooling refrigerant outlet at raw material inlet
19, 40 liquid level
21 Distillation vessel

Claims (2)

The polymerizable monomer composition having at least a polymerizable monomer, a colorant, a release agent, and a crosslinking agent is granulated in an aqueous dispersion medium containing a dispersant to form particles of the polymerizable monomer composition. In a method for producing a polymerized toner having colored polymerized toner particles obtained by polymerizing the polymerizable monomer of particles of a polymerizable monomer composition in the aqueous dispersion medium,
The polymerization apparatus in which the polymerization is performed has a polymerization vessel, a stirrer shaft having a stirring blade, and a baffle plate,
In the polymerization vessel, a liquid phase part of an aqueous dispersion medium having particles of a polymerizable monomer composition and a gas phase part are formed,
During the polymerization of the polymerizable monomer at a polymerization temperature of 50 to 90 ° C., the surface of the portion protruding from the gas phase portion of the stirrer shaft in the polymerization vessel is placed inside the stirrer shaft at a temperature of 0 to 40 ° C. Cooling is performed by circulating a cooling medium, and the cooling medium having a temperature of 0 to 40 ° C. is circulated inside the baffle plate through the surface of the portion of the baffle plate protruding into the gas phase in the polymerization vessel. A method for producing a polymerized toner, characterized in that generation of scale-like deposits on the stirrer shaft and the baffle plate is suppressed by cooling.   The method for producing a polymerized toner according to claim 1, wherein water or ethylene glycol is circulated as the cooling medium.

Images