JP3740202B2 - Toner production method - Google Patents

Description

Ｒ₁：Ｈ、ＣＨ₃、
Ｒ₂、Ｒ₃：置換又は未置換のアルキル基（好ましくはＣ₁〜Ｃ₄）、
【００５６】
負荷電性制御剤としては、例えば、有機金属錯体、キレート化合物が有効で、その例としては、アルミニウムアセチルアセトナート、鉄（II）アセチルアセトナート、３，５−ジターシャリーブチルサリチル酸クロム又は亜鉛等があり、特にアセチルアセトン金属錯体、サリチル酸系金属錯体又はその塩が好ましく、特にサリチル酸系金属錯体又はサリチル酸系金属塩が好ましい。
【００５７】
上述した荷電制御剤（結着樹脂としての作用を有しないもの）は、微粒子状として用いることが好ましい。この場合、この荷電制御剤の個数平均粒径は、具体的には４μｍ以下（更には３μｍ以下）が好ましい。
トナーに内添する際、この様な荷電制御剤は、結着樹脂１００重量部に対して０．１〜２０重量部（更には０．２〜１０重量部）用いることが好ましい。
【００５８】
トナーが磁性トナーの場合は、磁性トナー中に含まれる磁性材料としては、例えば、マグネタイト、γ−酸化鉄、フェライト、鉄過剰型フェライト等の酸化鉄；鉄、コバルト、ニッケルの様な金属或いはこれらの金属とアルミニウム、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、バナジウムの様な金属との合金及びその混合物等が挙げられる。
これらの強磁性体は、平均粒径が０．１〜１μｍ、好ましくは０．１〜０．５μｍ程度のものが望ましく、磁性トナー中に含有させる量としては、樹脂成分１００重量部に対し６０〜１１０重量部、好ましくは樹脂成分１００重量部に対し６５〜１００重量部である。
【００５９】
トナーに使用される着色剤としては、従来より知られている染料及び／又は顔料が使用可能である。例えば、カーボンブラック、フタロシアニンブルー、ピーコックブルー、パーマネントレッド、レーキレッド、ローダミンレーキ、ハンザーイエロー、パーマネントイエロー、ベンジジンイエロー等が挙げられる。その含有量としては、結着樹脂１００部に対して０．１〜２０重量部、好ましくは０．５〜２０重量部、更にトナー像を定着したＯＨＰフィルムの透過性をよくする為には１２重量部以下が好ましく、更に好ましくは０．５〜９重量部がよい。
【００６０】
以上説明してきた様に、本発明によれば、重量平均粒径が１０μｍ以下のシャープな粒度分布を有するトナー製品を効率よく得ることが可能であり、特に重量平均粒径が７μｍ以下のシャープな粒度分布を有するトナー製品を効率よく得ることが出来る。
【００６１】
【実施例】
次に、本発明の実施例及び比較例を挙げて本発明を更に詳細に説明する。
実施例１
・スチレン−ブチルアクリレート−ジビニルベンゼン共重合体（モノマー重合
重量比８０.０／１９.０／１.０、重量平均分子量＝３５万) １００重量部
・磁性酸化鉄（平均粒径０．１８μｍ） １００重量部
・ニグロシン ２重量部
・低分子量エチレン−プロピレン共重合体 ４重量部
上記の処方の材料を、ヘンシェルミキサー（ＦＭ−７５型、三井三池化工機（株）製）でよく混合した後、温度１５０℃に設定した２軸混練機（ＰＣＭ−３０型、池貝鉄工（株）製）にて混練した。得られた混練物を冷却し、ハンマーミルにて１ｍｍ以下に粗粉砕し、トナー製造用の粉体原料である粗粉砕物を得た。
【００６２】
得られたトナー原料を図２に示す装置システムで微粉砕及び分級を行った。衝突式気流粉砕機２８には、図５に示す構成の装置を用い、鉛直線を基準とした加速管の長軸方向の傾き（以下、加速管傾きとする）が約０°（即ち、実質的に鉛直に設置）であり、衝突部材５１は図６に示すものを使用した。この衝突部材５１は、α＝５５°、β＝１０°、外径（直径）１００ｍｍのものを使用し、粉砕室５３の形状は、内径１５０ｍｍの円筒状のものとした。第１分級手段２２には、図３〜図４に示す構成の回転式気流分級機を用いた。分級ローター１２４の直径Ｌ₁は２００ｍｍ、分級ローター１２４の羽根の長さＬ₂は３０ｍｍであり、分級ローター１２４の中心と羽根の先端とを結ぶ直線と羽根とのなす角θを４５°に設定して使用した。又、分級ローター１２４の回転数は２，５００ｒ.ｐ.ｍ.とした。
【００６３】
本実施例では、先ず、テーブル式の第１定量供給機２１にて粗粉砕物からなる粉体原料を、３５．０ｋｇ／ｈの割合でインジェクションフィーダー３５にて、供給管１２５を介して図３に示した構成の回転式気流分級機２２に供給し、粗粉と微粉とに分級した。該分級機によって分級された粗粉は、粗粉排出ホッパー１３２を介して図５に示した構成の衝突式気流微粉砕機２８に導入し、微粉砕した。粉砕機２８の被粉砕物供給管４１より供給された粗粉は、圧力６．０ｋｇ／ｃｍ²(Ｇ）、６．０Ｎｍ³／ｍｉｎの圧縮空気を用いて粉砕された後、原料導入部にて供給されているトナー製造用の粉体原料と混合されて、再び第１分級手段である気流分級機２２へと導入し、閉回路粉砕を行った。一方、第１分級工程で回転式気流分級機２２で分級された微粉は、排気ファン１３１からの吸引エアーに同伴されながらサイクロン２３にて捕集され、第２定量供給機２４へと導入される。この時に回転式気流分級機２２で分級されて得られた微粉は、重量平均径が７．１μｍであり、粒径４．０μｍ以下の粒子が４５個数％、且つ粒径１０．８μｍ以上の粒子を３．０体積％含有するシャープな粒度分布を有していた。
【００６４】
次に、上記の第１分級手段の回転式気流分級機２２によって分級されて得られた微粉を、第２定量供給機２４に導入し、振動フィーダー２５、及びノズル１４８及び１４９を介して３０．０ｋｇ／ｈの割合で第２の分級工程の図１０の構成を有する３分割分級機２７に導入した。該分級機２７では、コアンダ効果を利用して、粗粉体、中粉体及び微粉体の３種の粒度に分級される。
３分割分級機２７への導入に際しては、排出口１５８、１５９及び１６０に連通している捕集サイクロン２９、３０及び３１の吸引減圧による系内の減圧から派生する吸引力と原料供給ノズル１４８に取付けたインジェクションフィーダー３２からの圧縮空気を利用した。導入された微粉は、０．１秒以下の瞬時に、粗粉体、中粉体及び微粉体の３種に分級された。分級されたもののうち、粗粉体は捕集サイクロン２９で捕集した後、先に説明した気流式微粉砕機２８に導入し、再度粉砕工程に導入した。
【００６５】
上記の第２分級工程で分級された中粉体（分級品）は、重量平均粒径が６．９μｍであり、粒径４．０μｍ以下を粒子の２５個数％含有し、粒径１０．０８μｍ以上の粒子を１．３体積％含有するシャープな粒度分布を有しており、トナー用の分級品として優れた性能を有していた。この時、投入された粉体原料の全量に対する最終的に得られた分級品の量の比率（即ち、分級収率）は８５％であった。
【００６６】
尚、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、次の測定装置を用いて行なった。即ち、測定装置としては、コールターカウンターＴＡ−II型或いはコールターマルチサイザーII（いずれもコールター社製）を用いた。電解質溶液には、１級塩化ナトリウムを用いて約１％ＮａＣｌ水溶液を調製して用いたが、例えば、ＩＳＯＴＯＮＲ−II(コールターサイエンティフィックジャパン社製）を使用することが出来る。測定方法としては、前記電解質溶液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ルゼンスルホン酸塩を０．１〜５ｍｌ加え、更に測定試料を２〜２０ｍｇ加える。試料を懸濁した電解質溶液は超音波分散機で約１〜３分間分散処理を行ない、前記測定装置により、アパーチャーとして１００μｍアパーチャーを用い、トナーの体積、個数を測定して体積分布と個数分布とを算出した。それから、本発明の係るところの体積分布から求める重量基準の重量平均粒径を求めた。
【００６７】
実施例２
実施例１と同様のトナー原料を用いて同様の装置システムで、微粉砕及び分級を行った。即ち、衝突式気流粉砕機には図５に示す構成のものを用い、実施例１と同様の装置条件で粉砕を行った。第２分級手段２７も実施例１と同様のものを用いた。又、第１分級手段には実施例１と同様の回転式気流分級機を用いたが、分級ローターの回転数を３，１００ｒ.ｐ.ｍ.とした。
本実施例においては、粉体原料を３２．０ｋｇ／ｈの割合で上記装置システムに供給し、第１分級工程及び粉砕工程によって重量平均粒径６．４μｍの微粉を得た。次に、この微粉を、第２定量供給機２４を介して２５．０ｋｇ／ｈの割合で第２分級手段２７に導入し、重量平均粒径が６．１μｍの、粒径４．０μｍ以下の粒子を３２個数％含有し、且つ粒径１０．０８μｍ以上の粒子を０．５体積％含有するシャープな粒度分布を有する分級品（中粉体）を分級収率７７％で得た。
【００６８】
実施例３
実施例１と同様のトナー原料を用いて同様の装置システムで、微粉砕及び分級を行った。即ち、衝突式気流粉砕機には図５に示す構成のものを用い、実施例１と同様の装置条件で粉砕を行った。第２分級手段２７も実施例１と同様のものを用いた。
第１分級手段２２には、分級ローター１２４の直径Ｌ₁が３００ｍｍ、羽根の長さＬ₂が３５ｍｍ、分級ローター１２４の中心と羽根の先端とを結ぶ直線と羽根とのなす角θが６０°のものを使用し、分級ローター１２４の回転数を３，１００ｒ.ｐ.ｍ.にした。
本実施例においては、粉砕原料を３２．０ｋｇ／ｈの割合で上記装置システムに供給し、第１分級工程及び粉砕工程によって重量平均粒径５．９μｍの微粉を得た。次に、この微粉を、第２定量供給機２４を介して２５．０ｋｇ／ｈの割合で、第２分級手段２７に導入した結果、重量平均粒径５．８μｍの、粒径４．０μｍ以下の粒子を３７個数％含有し、且つ粒径１０．０８μｍ以上の粒子を含有しないシャープな粒度分布を有する分級品を分級収率７５％で得た。
【００６９】
実施例４
・不飽和ポリエステル樹脂 １００重量部
・銅フタロシアニン顔料(C.I.Pigment Blue15) ４．５重量部
・荷電制御剤（サリチル酸クロム錯体） ４．０重量部
上記の処方の材料を、ヘンシェルミキサー（ＦＭ−７５型、三井三池化工機（株）製）でよく混合した後、温度１００℃に設定した２軸混練機（ＰＣＭ−３０型、池貝鉄工（株）製）にて混練した。得られた混練物を冷却し、ハンマーミルにて１ｍｍ以下に粗粉砕し、トナー製造用の粉体原料である粗粉砕物を得た。
【００７０】
上記で得られた粉体原料を用い、図２に示す装置システムで粉砕及び分級を行った。
衝突式気流粉砕機２８には図５に示す構成の装置を用い、実施例１と同様の装置条件で粉砕を行った。第２分級手段２７は、実施例１と同様のものを用いた。又、第１分級手段２２には実施例１と同様の構成の装置を用いたが、分級ローター１２４の直径Ｌ₁が２００ｍｍ、分級ローター１２４の羽根の長さＬ₂が３０ｍｍ、θが４５°のものを用い、分級ローター１２４の回転数を３，５００ｒ.ｐ.ｍ.として分級した。
【００７１】
本実施例では、テーブル式の第１定量供給機２１にて粗粉砕物からなる粉体原料を、２８．０ｋｇ／ｈの割合でインジェクションフィーダー３５にて、供給管１２５を介して図３に示した構成の回転式気流分級機２２に供給して分級した。該分級機によって分級された粗粉は、粗粉排出ホッパー１３２を介して図５に示した構成の衝突式気流微粉砕機２８に導入した。該粉砕機２８の被粉砕物供給管４１より供給された粗粉は、圧力６．０ｋｇ／ｃｍ²（Ｇ）、６．０Ｎｍ³／ｍｉｎの圧縮空気を用いて粉砕した後、原料導入部にて供給されているトナー用粉体原料と混合しながら、再び気流分級機２２へと導入して循環させ、閉回路粉砕を行った。第１分級手段の回転式気流分級機２２で分級された微粉は、排気ファン１３１からの吸引エアーに同伴されながらサイクロン２３にて捕集される。尚、この時の微粉の重量平均粒径は７．０μｍであった。
【００７２】
この得られた細粉を、第２定量供給機２４を介して、振動フィーダー２５、及びノズル１４８及び１４９を介して２５．０ｋｇ／ｈの割合で第２分級手段２７に導入し、コアンダ効果を利用して粗粉体、中粉体及び微粉体の３種に分級し、中粉体をトナー製品として用いる分級品とした。
【００７３】
この結果得られた分級品は、重量平均粒径が６．５μｍであり、粒径４．０μｍ以下を粒子の２７個数％含有し、粒径１０．０８μｍ以上の粒子を１．４体積％含有するシャープな粒度分布を有しており、トナー用の分級品として優れた性能を有していた。この時、投入された粉体原料の全量に対する最終的に得られた中粉体の量の比率（即ち、分級収率）は８０％であった。
【００７４】
実施例５
実施例４と同様のトナー原料を用いて同様の装置システムで、微粉砕及び分級を行った。即ち、衝突式気流粉砕機には図５に示す構成のものを用い、第２分級手段２７には実施例１と同様のものを用いた。又、第１分級手段には実施例４と同様の図４に示した構成の回転式気流分級機を用いたが、分級ローター１２４の直径Ｌ₁が３００ｍｍ、羽根の長さＬ₂が３５ｍｍ、θが６０°のものを用い、分級ローター１２４の回転数を３，５００ｒ．ｐ．ｍ．とした。
本実施例においては、粉体原料を２８．０ｋｇ／ｈの割合で上記装置システムに供給し、第１分級工程及び粉砕工程によって重量平均粒径６．４μｍの微粉を得た。そして、この微粉を、第２定量供給機２４を介して２５．０ｋｇ／ｈの割合で第２分級手段２７に導入した結果、重量平均粒径が６．０μｍの、粒径４．０μｍ以下の粒子を３５個数％含有し、且つ粒径１０．０８μｍ以上の粒子を０．２体積％含有するシャープな粒度分布を有する分級品を分級収率７６％で得た。
【００７５】
比較例１
実施例１と同様の処方の材料を、ヘンシェルミキサー（ＦＭ−７５型、三井三池化工機（株）製）でよく混合した後、温度１５０℃に設定した２軸混練機（ＰＣＭ−３０型、池貝鉄工（株）製）にて混練した。得られた混練物を冷却し、ハンマーミルにて１ｍｍ以下に粗粉砕し、トナー製造用の粗砕物を得た。
得られたトナー原料を、図２に示す装置システムで粉砕及び分級を行った。但し、粉砕機２８には図１１に示した従来の衝突式気流粉砕機を用い、第１分級手段には図１２の構成のものを用いた。尚、第２分級手段２７には、実施例１と同様のものを用いた。
【００７６】
図１２において、搬送エアーと共に粉体供給筒２８０から導入される粉体原料が、その底部に中央部が高い傾斜状の分級板２００が設けられている分級室２５０に導入され、該分級室２５０において、粉体原料が共に流入される気流により旋回流動され、分級ルーバー２９０を介して微粉と粗粉とに遠心分離され、微粉は分級板２００の中央部に設けられた微粉排出シュート２２０から排出され、粗粉は分級板２００の外周部に設けられた粗粉排出口２１０から排出されるものである。
【００７７】
本比較例では、テーブル式の第１定量供給機２１にて粉体原料を１３．０ｋｇ／ｈの割合で、インジェクションフィーダー３５にて粉体供給筒２８０を介して図１２に示した気流分級機に供給し、分級を行った。分級された粗粉は、粗粉排出ホッパー２３０を介して、図１１に示した従来の衝突式気流粉砕機２８の被粉砕物供給口１６５より供給し、圧力６．０ｋｇ／ｃｍ²（Ｇ）、６．０Ｎｍ³／ｍｉｎの圧縮空気により粉砕した後、原料導入部３７にて供給されているトナー製造用の粉砕原料と混合しながら、再び該気流分級機に循環させて閉回路粉砕を行った。第１分級手段によって分級された微粉は、吸引ファンからの吸引エアーに同伴されながらサイクロン２３にて捕集され、第２定量供給機２４に導入された。この時の微粉の重量平均径は７．１μｍであり、粒径４．０μｍ以下の粒子を５７個数％含有し、粒径１０．０８μｍ以上の粒子を８．０体積％含有するブロードな粒度分布を有していた。
【００７８】
この得られた微粉を第２定量供給機２４を介し、更に振動フィーダー２５を介して実施例１で用いたと同様の第２分級手段２７へ１５．０ｋｇ／ｈの割合で導入した。
その結果、重量平均径６．９μｍであり、粒径４．０μｍ以下の粒子を２７個数％含有し、粒径１０．０８μｍ以上の粒子を１．５体積％含有する粒度分布を有する分級品（中粉体）を分級収率８１％で得た。この様に、実施例１に比べて、分級・粉砕処理効率に劣っていた。
【００７９】
比較例２
実施例１と同様のトナー原料を用いて同様の装置システムで、微粉砕及び分級を行った。但し、衝突式気流粉砕機２８は図１１に示す従来の構成のものを用い、第１分級手段には図１２に示した構成のものを用い、比較例１と同様の装置条件で粉砕を行った。尚、第２分級手段２７には、実施例１と同様のものを用いた。
粉体原料を１０．０ｋｇ／ｈの割合で第１分級手段２２に供給し、重量平均径が６．３μｍの微粉を得た。この微粉を１２．０ｋｇ／ｈの割合で第２分級手段２７に導入し、重量平均径６．１μｍであり、粒径４．０μｍ以下の粒子を３３個数％含有し、且つ粒径１０．０８μｍ以上の粒子を０．５体積％含有する粒度分布を有する分級品を分級収率７０％で得た。この様に、実施例２に比べて、分級・粉砕処理効率及び分級効率共に劣っていた。
【００８０】
比較例３
実施例４と同様の処方の材料を、ヘンシェルミキサー（ＦＭ−７５型、三井三池化工機（株）製）でよく混合した後、温度１００℃に設定した２軸混練機（ＰＣＭ−３０型、池貝鉄工（株）製）にて混練した。得られた混練物を冷却し、ハンマーミルにて１ｍｍ以下に粗粉砕し、トナー製造用の粉体原料である粗粉砕物を得た。
得られたトナー原料を図２に示す装置システムで粉砕及び分級を行った。但し、粉砕機には図１１に示した構成を有する従来の衝突式気流粉砕機を用い、第１分級手段には図１２の構成のものを用いた。尚、第２分級手段２７には、実施例１と同様のものを用いた。
【００８１】
本比較例では、テーブル式の第１定量供給機２１にて粉砕原料を１２．０ｋｇ／ｈの割合で、インジェクションフィーダー３５にて粉体供給筒２８０を介して図１２に示した気流分級機に供給した。該分級機で分級された粗粉は、粗粉排出ホッパー２３０を介して、図１１に示した衝突式気流粉砕機の被粉砕物供給口１６５より供給し、圧力６．０ｋｇ／ｃｍ²（Ｇ）、６．０Ｎｍ³／ｍｉｎの圧縮空気を用いて粉砕した後、原料導入部にて供給されている粉体原料と混合しながら、再び第１分級手段２２に循環させて、閉回路粉砕を行った。一方、第１分級工程で分級された微粉は、排気ファンからの吸引エアーに同伴されながらサイクロン２３にて捕集され、第２定量供給機２４に導入された。尚、この時の微粉の重量平均径は７．０μｍであった。
【００８２】
この得られた微粉を第２定量供給機２４を介し、更に振動フィーダー２５を介して第２分級手段２７へ１４．０ｋｇ／ｈの割合で導入した。その結果、重量平均径６．５μｍであり、粒径４．０μｍ以下の粒子を２８個数％含有し、粒径１０．０８μｍ以上の粒子を１．６体積％含有する粒度分布を有する分級品を分級収率７６％で得た。この様に、実施例４に比べて、分級・粉砕処理効率に劣っていた。
【００８３】
実施例及び比較例の装置システムと分級・粉砕結果

【００８４】
【発明の効果】
以上説明した様に、本発明のトナーの製造方法によれば、シャープな粒度分布の小粒径のトナーが高い処理効率で、且つ高い分級収率で得られ、しかもトナー製造の分級・粉砕工程におけるトナーの融着、粗粒化或いは凝集といった問題の発生が有効に防止され、且つトナー成分による装置に対する摩耗が有効に防止される為、高品質のトナーを連続して安定して生産することができる。
又、本発明のトナーの製造方法によれば、従来法に比べ、画像濃度が安定して高く、耐久性に優れ、カブリ、クリーニング不良等の画像欠陥のない優れた画像を得ることの出来る、小粒径のシャープな所定粒度を有する優れた静電荷像現像用トナーが低コストで得られる。
特に、本発明によれば、重量平均径が１０μｍ以下の原料からシャープな粒度分布を有するトナーを効率良く得ることが可能であり、更には、重量平均径が７μｍ以下の原料から小粒径のシャープな粒度分布を有するトナーを効率よく得ることが可能である。
【図面の簡単な説明】
【図１】本発明のトナーの製造方法の概略を示すフローチャートの一例である。
【図２】本発明の製造方法を実施する為の装置システムの一例を示す概略図である。
【図３】本発明の製造方法に用いる第１分級手段の好ましい一実施例の概略断面図である。
【図４】図３における水平型回転ローターの拡大図及び拡大側面図である。
【図５】本発明の製造方法に用いる衝突式気流粉砕手段の好ましい一実施例の概略断面図である。
【図６】図５におけるＡ−Ａ’断面図である。
【図７】図５におけるＢ−Ｂ’断面図である。
【図８】図５におけるＣ−Ｃ’断面図である。
【図９】図５における衝突部材の拡大図である。
【図１０】第２分級手段に用いられる多分割分級機の一例の概略断面図である。
【図１１】従来の衝突式気流粉砕機の概略断面図である。
【図１２】従来の第１分級手段に用いられている気流式分級機の一例である。
【図１３】従来のトナーの製造方法の概略を示すフローチャートの一例である。
【符号の説明】
２１：第１定量供給機
２２：第１分級手段
２３：捕集サイクロン
２４：第２定量供給機
２５：振動フィーダー
２７：第２分級手段
２８：粉砕機
２９、３０、３１：捕集サイクロン
３２：インジェクションフィーダー
３３：製品
３４：微小粉
３５：インジェクションフィーダー
３６：供給管
３７：原料導入部
４１：被粉砕物供給管
４２：被粉砕物
４３：加速管
４４：スロート部
４５：高圧気体噴出ノズル
４６：被粉砕物供給口
４７：高圧気体供給口
４８：高圧気体チャンバー
４９：高圧気体導入菅
５０：加速管出口
５１：衝突部材
５２、５２’：衝突面
５３：粉砕室
５４：粉砕室側壁
５５：粉砕物排出口
９１：衝突部材支持体
９２：高圧気体導入管
１０１：被粉砕物供給口
１２１：本体ケーシング
１２２：分級室
１２３：案内室
１２４：分級ローター
１２５：原料投入口
１２６：エアー投入口
１２８：周波数変換機
１２９：微粉排出管
１３０：微粉回収手段
１３１：吸引ファン
１３２：ホッパー
１３３：ロータリーバルブ
１３４：羽根
１４８、１４９：原料供給管
１５８、１５９、１６０：排出口
１６１：高圧気体供給ノズル
１６２：加速管
１６３：加速管出口
１６４：衝突部材
１６５：粉砕原料供給口
１６６：衝突面
１６７：粉砕物排出口
１６８：粉砕室
２００：分級板
２０１：分級機本体ケーシング
２１０：粗粉排出口
２２０：微粉排出シュート
２３０：粗粉排出ホッパー
２４０：案内筒上部
２５０：分級室
２５４：案内筒
２６０：上部カバー
２７０：分級下部ケーシング
２８０：粉体供給筒
２９０：分級ルーバー[0001]
BACKGROUND OF THE INVENTION
The present invention is intended to efficiently obtain a high-quality electrostatic image developing toner having a small particle size and a sharp particle size distribution by efficiently crushing and classifying small particles having a binder resin. The present invention relates to a toner manufacturing method.
[0002]
[Prior art]
In image forming methods such as electrophotography, electrostatic photography, and electrostatic printing, toner for developing an electrostatic charge image is used.
In recent years, with higher image quality and higher definition of copying machines, printers, etc., the performance required of toner as a developer has become more severe, the particle size of the toner has become smaller, and the particle size distribution of the toner has become coarser. There has been a demand for a sharp product that does not contain particles and has few ultrafine powders.
[0003]
As a general method for producing a toner for developing an electrostatic charge image, a binder resin for fixing to a transfer material, various colorants for producing a color as a toner, and a charge control agent for imparting electric charges to particles In the so-called one-component development method as described in Japanese Patent Application Laid-Open No. 54-42141 and Japanese Patent Application Laid-Open No. 55-18656, in addition to these, the toner itself is provided with transportability and the like. Various magnetic materials are used, and if necessary, other additives such as release agents and fluidity-imparting agentsTheIn addition, dry-mixing, and then melt-kneading with a general-purpose kneading device such as a roll mill, an extruder, etc., cooling and solidifying, then finely kneading the kneaded material with various pulverizing devices such as a jet airflow pulverizer and a mechanical collision pulverizer The resulting coarsely pulverized product is introduced into various air classifiers and classified to obtain a classified product having a uniform particle size necessary as a toner, and further, a fluidizing agent, a lubricant, etc. Is externally added and dry mixed to form a toner for image formation. In the case of the toner used in the two-component development method, various magnetic carriers and the above toner are mixed and then used for image formation.
[0004]
In order to obtain toner particles composed of fine particles having a required particle size, the method shown in the flowchart of FIG. 13 has been generally employed. That is, as shown in FIG. 13, the powder raw material consisting of the coarsely pulverized toner is first or continuously supplied to the first classification means in the first classification step to classify into coarse powder and fine powder. Is done. Of the classified particles, the coarse powder mainly composed of a coarse particle group having a specified particle size or more is sent to the pulverizing means and finely pulverized, and then introduced again to the first classifying means and classified and circulated. The The fine powder mainly composed of particles within the specified particle size range and particles having a particle size equal to or smaller than the specified particle diameter is sent to the second classifying means, and the medium powder mainly composed of particles having the specified particle size. And a fine powder (hereinafter referred to as ultrafine powder) whose main component is a particle group having a prescribed particle size or less. The obtained intermediate powder is used as a classified product for producing toner.
[0005]
As the pulverizing means used in the conventional classification and pulverization step, various pulverization apparatuses are used. For the pulverization of the toner coarse powder mainly composed of the binder resin, a jet stream as shown in FIG. 11 was used. Jet airflow pulverizers, particularly collision-type airflow pulverizers, are used. In such a collision type air pulverizer using a high-pressure gas such as a jet stream, the powder raw material, which is the material to be crushed, is transported by the jet stream and injected from the outlet of the acceleration tube, and the powder raw material is discharged from the acceleration tube. The powder raw material is pulverized by the impact force of the impact member which is provided to face the opening surface of the impact member.
For example, in the collision-type airflow crusher shown in FIG. 11, the collision member 164 is provided so as to face the outlet 163 of the acceleration tube 162 connected to the high-pressure gas supply nozzle 161, and the high-pressure gas supplied to the acceleration tube 162 The powder raw material is sucked into the acceleration pipe 162 from the powder raw material supply port 165 communicated in the middle of the acceleration pipe 162, and the powder raw material is jetted together with the high-pressure gas to collide with the collision surface 166 of the collision member 164. The powder raw material is pulverized by the impact force, and the pulverized material is discharged from the pulverization discharge port 167.
[0006]
However, in the collision-type airflow pulverizer of FIG. 11, since the supply port 165 of the object to be pulverized is provided in the middle of the acceleration pipe 162, the powder raw material that is the object to be pulverized introduced into the acceleration pipe 162 is Immediately after passing through the pulverized object supply port 165, the high-pressure air flow ejected from the high-pressure gas supply nozzle 161 is dispersed and rapidly accelerated in the high-pressure air stream while changing the flow path toward the acceleration tube outlet 163. In this state, relatively coarse particles of the pulverized material flow in the lower part of the acceleration tube due to the influence of inertial force, while relatively fine particles flow in the higher part of the acceleration tube. The raw material particles are not sufficiently uniformly dispersed and collide with the collision member 164 in the crushing chamber 168 in a concentrated manner while being separated into a flow having a high concentration and a low flow. For this reason, there existed a problem that a grinding | pulverization efficiency fell easily and it was easy to cause the fall of processing capacity.
[0007]
Furthermore, since the collision surface 166 tends to generate a portion having a high dust concentration consisting of the crushed material before the collision and the pulverized material after the collision locally on the collision surface 166 in the vicinity thereof, the crushed material is low in resin or the like. In the case of containing a melting point substance, the pulverized product is likely to be fused, coarsened, or agglomerated. In addition, when the object to be crushed is wearable, local powder wear tends to occur on the collision surface 166 of the collision member 164 and the acceleration tube 162, and the frequency of replacement of the collision member 164 increases. However, there is a point to be improved from the viewpoint of stably producing toner.
[0008]
Conventionally, various classifiers have been proposed as airflow classifiers that are connected to the collision type airflow pulverizer as described above and used to classify powder materials finely pulverized by the pulverizer. However, a typical example is a dispersion separator (manufactured by Nippon Pneumatic Industry Co., Ltd.) as shown in FIG. As an outline, the powder material introduced from the powder supply cylinder together with the carrier air is introduced into a classification chamber 250 provided with an inclined classification plate 200 having a high central portion at the bottom, and the classification chamber 250. , The powder material is swirled and flowed by the airflow that flows together, and is centrifuged into fine powder and coarse powder through the classification louver 290, and the fine powder is discharged from the fine powder discharge chute 220 provided at the center of the classification plate 200. The coarse powder is discharged from a coarse powder discharge port 210 provided on the outer peripheral portion of the classification plate 200.
[0009]
However, such conventional airflow classifiers have the following problems.
That is, as shown in FIG. 12, the powder material supply unit to the classification chamber 250 of this type of airflow classifier has a cyclone shape, and the guide tube 254 is provided at the center of the upper surface of the upper cover 260. Is provided in an upright shape, and a powder supply cylinder 280 is connected to the upper outer peripheral surface of the guide cylinder 254. The powder material supplied via the powder supply cylinder 280 is supplied to the guide cylinder 254. A powder supply cylinder 280 is connected to the upper part of the guide cylinder 254 so as to be introduced in the inner circumferential tangential direction. Therefore, when the powder material is supplied from the powder supply cylinder 280 into the guide cylinder 254, the powder material falls while turning along the inner peripheral surface of the guide cylinder 254. In this case, since the powder material falls from the powder supply cylinder 280 in a band shape along the inner peripheral surface of the guide cylinder 254, the distribution and concentration of the powder material flowing into the classification chamber 250 become non-uniform, that is, The powder material flows into the classification chamber 250 only from a part of the inner peripheral surface of the guide tube 254, and there is a problem that the dispersion of the powder material is bad. In addition, if the processing amount is increased and the processing efficiency is increased, the powder material is more likely to agglomerate and the dispersion is not sufficiently performed. Therefore, the classifier having the above-described configuration performs high-precision classification. There is a problem that can not be.
[0010]
On the other hand, in recent years, with the development of high image quality, high definition, and energy saving measures for copying machines, printers, etc., there has been a demand for toners with a smaller particle size as a developer and having a sharp particle size distribution. . Further, as a binder resin used as a constituent material of the toner, a resin having a low melting point, a low softening point, and a low glass transition point is used. For this reason, if it is attempted to reduce the particle size of the toner by the conventional toner manufacturing method that performs pulverization / classification as described above, first, the processing efficiency of the classification means in the first classification process is poor, and the first classification process. Since the pulverization efficiency of the airflow type fine pulverizer that finely pulverizes the coarse powder classified in step 1 is poor, the dispersion of the first classification means and the occurrence of agglomeration increase, making it impossible to perform high-precision classification. The particle size distribution of the toner supplied to the second classifying means becomes broad, resulting in a decrease in classification accuracy and classification yield of the classified product obtained by the second classifying means, and having a small particle size and a sharp particle size distribution. There has been a problem that toner products cannot be obtained efficiently.
[0011]
Further, since the binder resin used as a constituent material of the toner is a resin having a low melting point, a low softening point, and a low glass transition point, the vicinity of the collision surface generated in the conventional collision type airflow crusher described above is used. There is a problem that it is difficult to obtain a toner product of good quality because the local flow causes fusion, coarsening, or aggregation of the toner.
[0012]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a manufacturing method that solves various problems in the above-described prior art, particularly in the conventional manufacturing method of toner for developing electrostatic images.
Another object of the present invention is to provide a production method capable of efficiently producing a toner for developing an electrostatic image. That is, an object of the present invention is to provide a production method capable of efficiently producing a toner for developing an electrostatic image having a fine particle size distribution. That is, the present invention melts and kneads a mixture containing a binder resin, a colorant and an additive, cools the melt-kneaded product, and then coarsely pulverizes the powder raw material composed of a group of solid particles. It is an object of the present invention to provide a method capable of producing a particle product (used as a toner) having a particle size distribution efficiently and with high yield.
In particular, an object of the present invention is to provide a toner production method capable of efficiently producing a toner for developing an electrostatic image having a small and sharp particle size distribution with a weight average particle size of 10 μm or less, more preferably 7 μm or less. It is in.
[0013]
[Means for Solving the Problems]
The above object is achieved by the present invention described below. That is, the present invention provides a powder comprising a coarsely pulverized product obtained by melt-kneading a mixture containing at least a binder resin and a colorant, cooling the obtained kneaded product, and then pulverizing the cooled product by a pulverizing means. The body material is first introduced into the first classification step using a rotary airflow classification means having a horizontal rotary rotor to classify into fine powder and coarse powder, and then the classified fine powder is introduced into the second classification step. Then, a classified product for producing toner is obtained by classification, and the coarse powder classified in the first classification step is used as the material to be pulverized, and an acceleration tube for accelerating the material to be pulverized by high-pressure gas and the material to be pulverized A pulverization chamber for finely pulverizing a material, and the pulverization chamber is provided with a collision member having a collision surface provided to face the opening surface of the outlet of the acceleration tube.ThroatThe part has an object supply port for supplying the object to be pulverized into the accelerating tube, and the collision surface includes a projecting central part protruding from the center and a cone-shaped outer peripheral collision surface provided on the outer periphery thereof. The material to be crushed by the collision member in the pulverization chamber is further introduced into a collision-type airflow pulverization means having a side wall for further pulverization by collision, and the pulverized material is It is mixed with the powder raw material and re-introduced into the first classification process to be circulated.A method for producing toner, wherein the horizontal rotary rotor has a plurality of blades arranged at regular intervals on the same circumference, and each blade has a straight line connecting the center of the rotary rotor and the tip of the blade. It is arranged so as to form an angle θ of 35 to 65 ° with respect to the diameter L ₁ Is 100 to 1,000 mm, and the length L of the blade ₂ Is 10 to 100 mm, and the horizontal rotary rotor is rotated at 1,000 to 8,000 r. . p . m . Rotate with to classifyThis is a method for producing a toner.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an example of a flowchart showing an outline of a method for producing a toner of the present invention. In the method for producing a toner of the present invention, a mixture containing at least a binder resin and a colorant is melt-kneaded. A coarsely pulverized product obtained by cooling the kneaded product and then pulverizing the cooled product by a pulverizing meansTheUsed as a powder raw material. First, the powder raw material is classified into coarse powder and fine powder by the first classification means in the first classification step, and the classified fine powder is shown in the second classification means in the second classification step, for example, FIG. Is introduced into a three-part classifier as described above to obtain a classified product as a toner product (in the case of FIG. 1, medium powder), the coarse powder is finely pulverized by a pulverizer, and the resulting finely pulverized product is again classified into the first class. Introduced into the means and circulated Such a toner production method according to the present invention is characterized in that a rotary airflow classifier having a horizontal rotary rotor is used as the first classifying means, and the coarse powder classified by the first classifying means is further finely pulverized. A specific collision type airflow crusher is used as the crushing means.
[0015]
Furthermore, as a preferable aspect of the present invention, the rotary airflow classifier has a plurality of blades arranged at regular intervals on the same circumference, and each blade has a center of the rotating rotor and a tip of the blade. It is arranged so as to form a constant angle θ with respect to the connecting straight line, and the diameter L of the horizontal rotary rotor₁Is 100 to 1,000 mm, blade length L₂Is preferably 10 to 100 mm, and an angle θ between the straight line connecting the center of the rotating rotor and the tip of the blade and the blade is 20 ° to 90 °. If the rotary airflow classifier having such a structure is used, the powder raw material, which is the toner material introduced into the rotary airflow classifier, is uniformly dispersed by the forced vortex generated by the horizontal rotary rotor, Even if the amount of processing increases, the fine powder particles of toner can be classified with high accuracy without causing the fine particles to aggregate in the classifier. In particular, when the horizontal rotary rotor having the above structure is classified by rotating at 1,000 to 8,000 rpm, the peripheral speed of the rotating rotor and the inclination of the blades are optimized, and more efficiently. Specifically, since it is possible to generate a forced vortex with low energy, it is possible to classify economically and precisely.
[0016]
In the present invention, the pulverizing means used in combination with the first classifying means as described above includes an accelerating tube for accelerating and accelerating the object to be crushed by the high-pressure gas, and a pulverizing chamber for finely pulverizing the object to be crushed In the pulverization chamber, a collision member having a collision surface provided opposite to the opening surface of the outlet of the acceleration tube is provided, and a material to be crushed is supplied into the acceleration tube at the rear end portion of the acceleration tube. The collision surface has a shape composed of a projecting central portion protruding from the center and a cone-shaped outer peripheral collision surface provided on the outer periphery thereof, and further in the grinding chamber. Since the collision type airflow crushing means having a side wall for further crushing the object to be pulverized by the collision member is used, the object to be crushed and the compressed air that are ejected from the acceleration tube to the pulverization chamber are used. The solid-gas mixed flow is primarily pulverized at the collision surface at the center of the protrusion and is uniformly dispersed. After being secondary pulverization further the outer peripheral colliding surface, since that is the tertiary pulverization by grinding chamber sidewall, it is capable of very efficient grinding.
[0017]
In this way, in the present invention, the classification efficiency in the first classification step is achieved by using the rotary airflow classification means described above as the first classification means and the specific collision-type airflow fine grinding means in the subsequent fine grinding part. In addition, since the pulverization efficiency is greatly improved, even if the toner particle size is reduced, the supply amount to the first classification means does not increase. For example, the supply amount of the powder raw material to the first classification means does not increase. Even if the number is increased, the effect of the forced vortex of the rotary airflow classifying means enables high-precision classification without causing toner aggregation in the classifier. As a result, the particle size distribution of the fine powder supplied to the second classifying means becomes sharp, and the yield of a classified product (toner product) having a desired particle size classified by the second classifying means is remarkably improved. Is possible.
Further, since the local flow in the vicinity of the pulverizer collision surface in the collision type airflow fine pulverization means is uniformly dispersed on the collision surface of the projection surface at the center, toner fusion, coarsening, or aggregation is suppressed. The
[0018]
Hereinafter, the toner production method of the present invention will be described more specifically with reference to the accompanying drawings.
FIG. 1 is an example of a flowchart showing an outline of the manufacturing method of the present invention. In the present invention, first, a predetermined amount of the powder raw material is supplied to the first classification means in the first classification step, and is classified into coarse powder and fine powder by the first classification means. After the classified coarse powder is introduced into the pulverizing means and finely pulverized, the finely pulverized product is again introduced into the first classifying means together with the newly supplied powder raw material. One fine powder is introduced into a classifier as a second classifying means and classified to obtain a classified product having a desired particle size distribution as a toner product. At this time, any classifier may be used as the second classifying means, but in order to obtain a classified product having a precise particle size distribution, at least the coarse powder region and the medium powder region as shown in FIG. In addition, it is preferable to use a multi-division classifier having a 3-fraction area of fine powder area. According to such a production method of the present invention, a toner having a sharp particle size distribution with a weight average particle diameter of 10 μm or less, more preferably 7 μm or less is controlled by controlling classification conditions and pulverization conditions. It becomes possible to manufacture efficiently.
[0019]
FIG. 2 shows an example of an apparatus system according to the manufacturing method of the present invention having the above-described configuration.
In this apparatus system, a powder raw material containing at least a binder resin and a colorant, which are toner materials, is first introduced into the first classifying means 22 via the first fixed quantity feeder 21, and coarse powder and fine powder. Classified. The classified fine powder is fed into the second fixed amount feeder 24 through the collection cyclone 23, and then introduced into the second classification means 27 through the vibration feeder 25. On the other hand, after the coarse powder classified by the first classification means 22 is fed into the pulverizer 28 and finely pulverized, the finely pulverized product is introduced again into the first classification means 22 together with the powder raw material to be newly input. Classification.
[0020]
As the first classifying means used in the present invention, a rotary airflow classifier having a horizontal rotating rotor that classifies by centrifugal force using a forced vortex is used. For example, a tea plex (ATP) classifier manufactured by Hosokawa Micron Corporation may be used. In the present invention, the accuracy of classification of fine powder and coarse powder is improved by using a rotary airflow classifier having a horizontal rotary rotor as shown in FIGS. 3 shows an overall view of the airflow classifier, and FIG. 4 shows a partially enlarged view and an enlarged side view of a horizontal rotary rotor (classification rotor) 124 of the airflow classifier.
[0021]
In FIG. 3, reference numeral 121 denotes a cylindrical main body casing. A classification chamber 122 is formed inside the main body casing 121, and a guide chamber 123 is provided below the classification chamber 122.
The rotary airflow classifier shown in FIG. 3 is an individual drive system, and generates a forced vortex using centrifugal force in the classification chamber 122 to classify it into coarse powder and fine powder. A classification rotor 124 is provided in the classification chamber 122, and the powder raw material 42 and air fed into the guide chamber 123 are swirled into the classification chamber 122 by suction from between the classification rotors 124. The powder raw material 42 is supplied from the raw material inlet 125, and air is taken in together with the powder raw material 42 from the inlet 126 and further from the raw material inlet 125. The powder raw material 42 is conveyed to the classification chamber 122 together with the inflow air. It is preferable that the air flowing in the guide chamber 123 through the inlet 125 and the powder material 42 are uniformly distributed to the respective classifying rotors 124 in order to be accurately classified. Further, the flow path to reach the classification rotor 124 needs to have a shape in which concentration does not easily occur. However, the position of the insertion port 125 is not limited to this.
[0022]
As shown in FIG. 4, the classifying rotor 124, which is a constituent member of the classifier, has a plurality of blades arranged at regular intervals on the same circumference, and each blade has a center of the rotating rotor, a tip of the blade, Are arranged so as to form a fixed angle θ with respect to a straight line connecting the two. The size of the classifying rotor 124 depends on the size of the classifier body.₁Is 100 to 1,000 mm, blade length L₂Is in the range of 10 to 100 mm, and the blade angle of the classification rotor 124 is movable, and the angle θ between the straight line connecting the center of the classification rotor 124 and the tip of the blade and the blade is 20 ° to 90 °. It is preferable that it is designed so that it can be arbitrarily changed within the numerical range. The speed control of the classifying rotor 124 having such a shape is performed through the frequency converter 128.
[0023]
In the present invention, the angle θ formed by the straight line connecting the center of the classification rotor 124 and the tip of the blade and the blade indicates the angle ABC formed by the straight line OA and the straight line BC as shown in FIG. If the angle θ is smaller than 20 °, it is difficult to generate a strong forced vortex, and even if a strong forced vortex can be generated, the high-speed rotation of the classifying rotor 124 is necessary, which is stable and safe. It is difficult and unfavorable to maintain a stable operation. Further, the more preferable range of the angle θ is 35 to 65 °. By doing so, a strong forced vortex can be efficiently generated in the classification chamber 122.
[0024]
The fine powder discharge pipe 129 is connected to a suction fan 131 via a fine powder collecting means 130 such as a cyclone or a dust collector. By operating the suction fan 131, the fine powder discharge pipe 129 is sucked into the classification chamber 122 from between the classification rotors 124. Forced vortex is generated by applying force.
[0025]
In the toner production method of the present invention, the air classifier used as the first classifying means has the above structure, and the sample to be classified is introduced into the classifier from the raw material inlet 125 at the lower part of the classifier. The That is, a collision-type airflow pulverizer to be described laterInTherefore, the air containing the finely pulverized material, the air used for pulverization, and the newly supplied powder raw material is supplied from the raw material inlet 125 into the guide chamber 123. The air containing the powder raw material flows between the classification rotors 124 from the guide chamber 123.
[0026]
The powder raw material flowing into the classification chamber 122 as described above acts on each particle by the forced vortex while being sufficiently dispersed in the classification chamber 122 where the forced vortex is generated by the classification rotor 124 that rotates at high speed. Centrifugation separates coarse powder and fine powder. The coarse powder in the classification chamber 122 passes through the coarse powder discharge hopper 132 connected to the lower part of the main body casing, and passes through the rotary valve 133 to be crushed material supply pipe of a collision type airflow fine pulverizer described later. After being supplied to 41 and further finely pulverized, the finely pulverized product is again introduced into the rotary air classifier as the first classifying means. The fine powder classified by the first classification means is discharged to the fine powder collection means 130 by the fine powder discharge pipe 129 and then introduced into the second classification means for further fine classification, which is excellent as a desired toner product. Get classifieds.
[0027]
As described above, in the toner manufacturing method of the present invention, it is preferable that the angle θ between the straight line connecting the center of the classification rotor 124 and the tip of the blade and the blade is35° ~65Using a rotary air classifier that rotates a horizontal rotary rotor that is in the range of ° C, a forced vortex is generated to classify the powder raw material. The rotational speed of the classifying rotor 124 is 1,000 to 8 Classifying as 1,000,000 rpmEffectIt is efficient and more preferable. When the horizontal rotary rotor having the structure as described above is rotated at such a high speed, a forced vortex is generated in the classification chamber 122.EffectIt is generated efficiently and the powder raw material is uniformly dispersed. As a result, high-precision classification can be performed without causing fine particles to aggregate even if the amount of treatment increases. In particular, by operating the rotary airflow classifier having the above-described configuration with the above-described rotation, the peripheral speed of the rotating classification rotor 124 and the inclination of the blades are optimized. Can generate forced vortices at low energy. As a result, for example, it is possible to classify a large amount of toner having a small particle size, which is impossible with the classification method using the airflow classifier as shown in FIG. Is possible.
[0028]
In the rotary air classifier as described above, the classification point is determined by the number of rotations of the classification rotor, and precise classification in the fine particle region is possible, but conventionally the efficiency of the grinding means connected to this is good. Therefore, it was difficult to obtain a toner having a small diameter, and even if it was obtained, a great amount of labor was required. However, in the present invention, since a collision type airflow crusher having a configuration as shown in FIG. 5 to be described later is used for the crushing means, the performance of the crushing process can be improved, and classification is performed by a rotary classifier. The resulting coarse powder is efficiently atomized. Further, the rotary classifier used in the present invention has an advantage that the classification point can be easily changed only by changing the number of rotations of the classification rotor, and the operability is excellent.
[0029]
If the rotational speed of the classification rotor 124 of the rotary air classifier used in the present invention is less than 1,000 rpm, the generation of forced vortex in the classification chamber 122 is not efficiently performed, and the powder raw material This is not preferable because the dispersion and classification are not sufficiently performed. On the other hand, if the rotational speed exceeds 8,000 rpm, it is difficult to maintain stable and safe operation, which is not preferable.
[0030]
Next, the pulverization means used in the present invention for further pulverizing the coarse powder classified by the first classification means as described above to obtain a pulverized product introduced again into the first classification means will be described. In the present invention, as the pulverizing means, for example, a collision type airflow pulverizer of the type illustrated in FIGS. 5 to 9 is used.
5 is an overall view of the main part of the collision-type airflow crusher. FIG. 6 is a cross-sectional view taken along the line AA ′ in FIG. 5, FIG. 7 is a cross-sectional view taken along the line BB ′ in FIG. FIG. 9 is an enlarged view of the collision member 51 in the crushing chamber.
[0031]
First, in the collision-type airflow pulverizer shown in FIG. 5, the object to be crushed 42 supplied from the object to be crushed supply pipe 41 is formed by the inner wall of the accelerating pipe throat portion 44 of the accelerating pipe 43 and the high-pressure gas jet nozzle 45. The material to be crushed is supplied to the accelerating tube 43 from an object supply port 46 (also a throat portion) formed between the outer wall and the outer wall. The central axis of the high-pressure gas ejection nozzle 45 and the central axis of the acceleration tube 43 are preferably substantially coaxial.
[0032]
On the other hand, the high-pressure gas is introduced from the high-pressure gas supply port 47, passes through the high-pressure gas chamber 48, preferably through a plurality of high-pressure gas introduction pipes 49, and travels from the high-pressure gas ejection nozzle 45 toward the acceleration pipe outlet 50. Erupting while rapidly expanding. At this time, due to the ejector effect generated in the vicinity of the acceleration tube throat portion 44, the object to be pulverized 42 is accompanied by the gas coexisting with the object to be pulverized 42, and is directed from the object to be pulverized supply port 46 toward the acceleration tube outlet 50. On the other hand, the acceleration is accelerated rapidly while being uniformly mixed with the high-pressure gas in the accelerating tube throat portion 44. And it collides with the collision surface 52 of the collision member 51 facing the acceleration tube outlet 50 in a state of a uniform solid-gas mixed flow without unevenness of the dust concentration. Since the impact force generated at the time of collision is given to sufficiently dispersed individual particles (object to be crushed 42), very efficient pulverization can be performed.
[0033]
The pulverized material crushed on the collision surface 52 of the collision member 51 further undergoes a secondary collision (or tertiary collision) with the side wall 54 of the pulverization chamber 53, and the pulverized material discharge port 55 disposed behind the collision member 51. More discharged.
Further, in the collision-type airflow crusher shown in FIG. 5, if the collision surface 52 of the collision member 51 is a collision surface having a conical projection at the center as shown in FIGS. The pulverized material can be uniformly dispersed, and high-order collision with the side wall 54 can be performed efficiently. Furthermore, when the pulverized product discharge port 55 is behind the collision member 51, the pulverized product can be discharged smoothly.
[0034]
That is, as shown in FIG. 9, by providing a cone-shaped central projecting portion with a central portion projecting on the raw material collision surface 52 of the collision member 51, the raw material to be crushed and compressed air ejected from the acceleration tube 43 are provided. The solid-gas mixed flow is primarily pulverized by the collision surface 52 on the projection surface of the collision member 51, and then secondarily pulverized by the conical collision surface 52 ′ provided on the outer periphery thereof, and then by the pulverization chamber side wall 54. Tertiary ground. At this time, the apex angle α (°) formed by the collision surface 52 at the center of the projection surface of the collision member 51 and the inclination angle β (°) with respect to the vertical surface of the outer peripheral collision surface 52 ′ and the central axis of the acceleration tube are as follows. When the above relationship is satisfied, grinding is performed very efficiently.
0 <α <90, β> 0
30 ≦ α + 2β ≦ 90
[0035]
That is, when α ≦ 90, the reflected flow of the pulverized material primarily pulverized by the central projection surface 52 disturbs the flow of the solid-gas mixed flow ejected from the acceleration tube 43, which is not preferable. Further, when β = 0, the outer peripheral collision surface 52 ′ is almost perpendicular to the solid-gas mixed flow, and the reflected flow at the outer peripheral collision surface flows toward the solid-gas mixed flow. Disturbance is undesirable. When β = 0, the outer collision surfacePowderWhen the body concentration is increased and a thermoplastic resin powder or a powder containing a thermoplastic resin as a main component is used as a raw material, a fused product and an agglomerate are likely to be formed on the outer peripheral collision surface. When such a fused product is produced, stable operation of the apparatus becomes difficult.
Further, when α and β are α + 2β <30, the impact force of the primary pulverization on the projection surface 52 is weakened, so that the pulverization efficiency is lowered, which is not preferable.
Also, when α and β are α + 2β <90, the reflected flow at the outer peripheral collision surface 52 ′ flows downstream of the solid-gas mixed flow, so that the impact force of the tertiary pulverization at the pulverization chamber side wall 54 becomes weak and the pulverization efficiency. Cause a decline.
[0036]
As described above, when α and β satisfy the following relationship, primary, secondary, and tertiary pulverization is efficiently performed, and the pulverization efficiency can be improved.
0 <α <90, β> 0
30 ≦ α + 2β ≦ 90
More preferable values of α and β are as follows.
0 <α <80
5 <β <40
[0037]
In the present invention, by using the collision-type airflow pulverizer having the above-described structure, the number of collisions can be increased and more effective as compared with the case where the conventional airflow pulverizer as shown in FIG. 11 is used. Since the powder particles can be made to collide with each other, the pulverization efficiency can be improved. Further, as described above, the pulverizer having the collision member 51 having the inclined collision surfaces 52 and 52 ′ as shown in FIG. 9 also has good dispersion of the pulverized material after the collision, as shown in FIG. Compared with a conventional pulverizer having a collision member 164 having a collision surface 166 that is 90 ° flat with respect to the acceleration tube 162, the fusion of the object to be crushed can be achieved when crushing a resin or a sticky substance. Aggregation and coarsening hardly occur, and pulverization with a high dust concentration is possible. In addition, even when pulverized raw materials with wear properties are used, the wear generated on the inner wall of the accelerating tube and the collision surface of the collision member is not concentrated locally, and the service life of these members can be extended and stable operation can be achieved. Is possible.
[0038]
In the toner production method of the present invention, the rotary air classifier having good classification efficiency and no aggregation of fine powders shown in FIGS. 3 to 4 described above, and the grinding efficiency shown in FIGS. By using in combination with a good collision airflow pulverizer, the pulverization efficiency of the pulverizer is improved compared to the conventional method, so that the burden on the first classifying means increases even when the toner is miniaturized. There is no. In addition, the increase in the dust concentration suppresses the toner aggregation that occurs when using a conventional classifier, resulting in highly accurate classification.TheCan be done. As a result, the second classification of the second classification process following the first classification process.ClassySince the fine powder supplied to the stage can be classified with high accuracy in which toner aggregation is suppressed, the classified product obtained in the second classification step has a sharp particle size distribution with a small particle size. A high quality product is obtained, and the classification yield by the second classification means is also greatly improved.
[0039]
Further, even if the supply amount of the toner powder raw material is increased and the burden on the first classifying means is increased, in the present invention, the classifying machine in the first classifying process has a rotary airflow classifier having a horizontal rotary rotor. And, more preferably, a rotating airflow classifier in which the peripheral speed of the classifying rotor 124 and the inclination of the blades are optimized is used, so that an efficient forced vortex flow is generated in the classifying chamber to generate toner. The powder raw material for production can be uniformly dispersed, and high-precision classification can be performed without causing aggregation. As a result, since a classified product (fine powder) having a small particle size and a sharp particle size distribution can be supplied to the second classifying means, the classification yield of the classification in the second classifying means is greatly improved. That is, according to the present invention, it is possible to obtain a toner product having a small particle diameter and a sharp particle size distribution with a weight average diameter of 10 μm or less, and further 7 μm or less.
[0040]
In the toner production method of the present invention, as described above, fine powder having a small particle size and a sharp particle size distribution can be supplied to the second classification means by the first classification step and the pulverization step. In this method, efficient classification is possible, and any known method may be used as the second classification means used in the present invention. Specifically, for example, as the second classifying means, at least a coarse powder area (first fraction area), a medium powder area (second fraction area), and a fine powder area (third fraction area) are provided. It is preferred to use a multi-division classification area. For example, a multi-division classifier of the type shown in FIG. 10 (cross-sectional view) is given as one of the specific examples, and more specifically, the Coanda effect having a Coanda block such as an Elbow Jet manufactured by Nippon Steel Mining Co., Ltd. The classifying means used is mentioned.
[0041]
The classification chamber having such a classification area mainly includes side walls 141 and 142, lower walls 143 and 144, and a Coanda block 145 having a shape as shown in FIG. The lower walls 143 and 144 have knife edge type classification edges 146 and 147, respectively, and the classification zones 146 and 147 divide the classification zone into three. Under the side wall 141, raw material supply pipes 148 and 149 that open to the classification chamber are provided, and a Coanda block 145 that is bent downward with respect to the extending direction of the bottom tangent of the supply pipe to draw a long elliptical arc is provided. Yes. The upper wall 150 of the classifying chamber has a knife-edge type inlet edge 151 directed toward the lower part of the classifying chamber, and further, inlet pipes 152 and 153 opening to the classifying chamber are provided at the upper part of the classifying chamber. Yes. The inlet pipes 152 and 153 are provided with gas introduction adjusting means 154 and 155 such as dampers, and static pressure meters 156 and 157, respectively. The positions of the classification edges 146 and 147 and the intake air edge 151 vary depending on the type of raw material to be classified and the desired particle size. Further, discharge ports 158, 159, and 160 that open into the classification chamber are provided on the bottom surface of the classification chamber so as to correspond to the respective classification areas. The discharge ports 158, 159 and 160 may be provided with opening / closing means such as valve means.
[0042]
The raw material supply pipe is preferably composed of a cylindrical raw material supply pipe 148 and a pyramidal cylindrical raw material supply pipe 149, but the ratio of the inner diameter of the raw material supply pipe 148 to the inner diameter of the narrowest portion of the raw material supply pipe 149 Is set to 20: 1 to 1: 1, preferably 10: 1 to 2: 1, a good insertion speed is obtained.
In addition, as a means for feeding the powder material to be classified into the supply pipe together with the air current, 0.1 to 3 kg / cm²A method of feeding the raw material and powder material naturally by increasing the size of the blower on the downstream side of the classification zone and increasing the negative pressure of the classification zone, or an injection feeder at the raw material powder inlet There is a method in which the raw material powder and the outside air are sucked by this and sent to the classification zone through a supply pipe.
[0043]
In the present invention, among the above-mentioned charging means, in particular, the method of naturally sucking outside air and powder raw material by increasing the negative pressure in the classification zone, or the method using an injection feeder is used in terms of the apparatus and operating conditions. Advantageous and preferred. In addition, it is possible to more effectively classify the toner for developing an electrostatic charge image that requires high-accuracy classification, and furthermore, a favorable effect is obtained in classification of toner having a weight average particle diameter of 10 μm or less. In particular, in the classification of toner having a weight average particle diameter of 7 μm or less, a further effect can be obtained.
[0044]
The classification operation in the multi-division classification area having the above configuration is performed as follows, for example. That is, the inside of the classification area is depressurized through at least one of the discharge ports 158, 159, and 160, and the raw material powder is supplied to the raw material supply pipes 148 and 149 at a flow rate of 50 m / sec to 300 m / sec by the airflow flowing by the depressurization. To supply to the classification area. That is, if the first fine powder is supplied to the classification region at a flow rate of less than 50 m / second, it is difficult to sufficiently disaggregate the fine powder, and this is not preferable because the classification yield and classification accuracy are likely to be lowered. When the first fine powder is supplied to the classification region at a speed exceeding 300 m / sec, the particles are easily pulverized by collision between the particles, and it is easy to generate ultrafine particles. Absent.
[0045]
By the above means, the powder raw material made of the first fine powder obtained in the first classification step to be supplied has a curved line due to the Coanda effect by the action of the Coanda block 145 and the action of a gas such as air flowing in at that time. In accordance with the size of each particle size, large particles (particles having a particle size exceeding the standard particle size) are intermediate in the first fraction area outside the air stream, that is, outside the classification edge 147. Particles (particles with a standard particle size) are in the second fractionation zone between the classification edges 146 and 147, and small particles (particles with a standard particle size) are in the third fractionation region inside the classification edge 146, respectively. Large particles (coarse powder) are discharged from the discharge port 158, intermediate particles (medium powder) are discharged from the discharge port 159, and small particles (fine powder) are discharged from the discharge port 160, respectively.
[0046]
In order to carry out the above-described method, the above-described devices are connected to each other by a communication means such as a pipe and used as an integrated device system as shown in FIG. That is, the classifier 27 in the apparatus system shown in FIG. 2 is as shown in FIG. 10, and the vibration feeder 25 and the collection cyclones 29, 30 and 31 are connected to this by communication means.
[0047]
When introducing into the multi-division classifier 27 as described above, the powder raw material is introduced into the 3-division classifier 27 at a flow rate of 50 m / sec to 300 m / sec. Since the size of the classification area of the multi-division classifier 27 is usually (10 to 50 cm) × (10 to 50 cm), the pulverized product is instantly divided into three or more particle groups in 0.1 to 0.01 seconds. Can be classified. Then, by means of the three-class classifier 27, large particles (particles exceeding the specified particle size: coarse powder), intermediate particles (particles having a specified internal particle size: medium powder), and small particles (particles having a specified particle size less than the specified particle size) : Fine powder). Thereafter, the coarse powder is sent to the collection cyclone 29 through the discharge conduit 158 and returned to the grinder 28. The medium powder is discharged out of the system through the discharge conduit 159 and is collected by the collection cyclone 31 to be collected as the toner product 33 as much as possible. The fine powder is discharged out of the system through the discharge conduit 160, collected by the collection cyclone 30, and then collected as a fine powder 34 having a specified outside particle diameter. The collection cyclones 29, 30 and 31 can also serve as a suction pressure reducing means for sucking and introducing the classified material through the nozzles 148 and 149.
Further, the coarse powder classified at this time may be returned to the pulverizer 28 or may be returned to the first fixed quantity supply device 21. In order to reduce the load on the first classifier 22 and reliably perform the pulverization by the pulverizer 28, it is more preferable to return the coarse powder directly to the pulverizer 28.
[0048]
The toner production method of the present invention can be preferably used to produce toner particles used for developing an electrostatic image.
To produce an electrostatic charge image developing toner, a mixture containing at least a binder resin and a colorant is used as a material. In addition, magnetic powder, a charge control agent, and other additives may be used as necessary. Used. As the binder resin, vinyl-based and non-vinyl-based thermoplastic resins are preferably used. These materials were sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melted, kneaded and kneaded using a heat kneader such as a roll, a kneader, and an extruder to make the resins compatible with each other. The pigment or dye is dispersed or dissolved therein, and after cooling and solidification, pulverization and classification can be performed to obtain a toner. In the present invention, the pulverization step and the classification step include the apparatus described above. Use the system.
[0049]
Hereinafter, constituent materials of the toner will be described.
As the binder resin used for the toner, the following binder resin for toner can be used when a heat-pressure fixing device or a heat-pressure roller fixing device having an oil application device is used.
For example, styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, etc., and homopolymers thereof; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer , Styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethacrylic copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether Copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene copolymers such as styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenol resins, Natural resin-modified phenol Fat, natural resin-modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumaroindene resin, petroleum-based Examples thereof include resins.
[0050]
In the heat and pressure fixing method or the heat and pressure roller fixing method in which little or no oil is applied, a so-called offset phenomenon in which a part of the toner image on the toner image support member is transferred to the roller, and the toner image The toner adhesion to the support member is an important issue. Since the toner that is fixed with less heat energy usually tends to be blocked or caked during storage or in a developing device, these problems must be taken into consideration at the same time. The physical properties of the binder resin in the toner are the most important factor in these phenomena. However, according to studies by the present inventors, if the content of the magnetic substance in the toner is reduced, the toner image is supported during fixing. Although the adhesion of the toner to the body is improved, offset is likely to occur, and blocking or caking is also likely to occur. Therefore, the selection of the binder resin is more important when using a heat and pressure roller fixing method in which almost no oil is applied. Preferable binder resins include, for example, a crosslinked styrene copolymer or a crosslinked polyester.
[0051]
Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid. Acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylateBMonocarboxylic acid having a double bond such as nitrile, acrylamide and the like; or a substituted product thereof; for example, dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like Body; for example, vinyl chloride, vinyl acetate, reposeIncenseVinyl esters such as vinyl acid; for example, vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; and vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; A mer is used alone or in combination of two or more.
[0052]
Here, as the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol diacrylate. Carboxylic acid ester having two double bonds such as methacrylate, 1,3-butanediol dimethacrylate; for example, divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide, divinylsulfone; and three or more vinyl groups Are used alone or as a mixture.
[0053]
In the case of using the pressure fixing method or the light heat pressure fixing method, a binder resin for pressure fixing toner can be used. For example, polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer Examples thereof include a copolymer, an ethylene-vinyl acetate copolymer, an ionomer resin, a styrene-butadiene copolymer, a styrene-isoprene copolymer, a linear saturated polyester, and paraffin.
[0054]
In addition, it is preferable to use a toner in which a charge control agent is blended (internally added) to the toner particles. The charge control agent makes it possible to control the optimum charge amount according to the development system. In particular, in the present invention, the balance between the particle size distribution and the charge can be further stabilized, and the charge control agent is used. This makes it possible to further clarify the functional separation and mutual capture for achieving high image quality for each particle size range as described above. Examples of positive charge control agents include, for example, modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate; Or in combination of two or more. Of these, nigrosine compounds and charge control agents such as quaternary ammonium salts are particularly preferably used.
Further, a positive charge control agent is obtained by using a monomer homopolymer represented by the following general formula (1) or a copolymer with a polymerizable monomer such as styrene, acrylic acid ester, and methacrylic acid ester as described above. In this case, these charge control agents also have an action as a binder resin (all or a part thereof).
[0055]
General formula (1)

R₁: H, CH_Three,
R₂, R_Three: Substituted or unsubstituted alkyl group (preferably C₁~ C_Four),
[0056]
As the negative charge control agent, for example, an organometallic complex or a chelate compound is effective. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, chromium 3,5-ditertiary butylsalicylate or zinc. In particular, an acetylacetone metal complex, a salicylic acid metal complex or a salt thereof is preferable, and a salicylic acid metal complex or a salicylic acid metal salt is particularly preferable.
[0057]
It is preferable to use the above-described charge control agent (having no action as a binder resin) in the form of fine particles. In this case, the number average particle diameter of the charge control agent is preferably 4 μm or less (more preferably 3 μm or less).
When internally added to the toner, such a charge control agent is preferably used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) with respect to 100 parts by weight of the binder resin.
[0058]
When the toner is a magnetic toner, examples of the magnetic material contained in the magnetic toner include iron oxides such as magnetite, γ-iron oxide, ferrite, and iron-rich ferrite; metals such as iron, cobalt, and nickel, or these And alloys of these metals with aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. .
These ferromagnetic materials have an average particle size of 0.1 to 1 μm, preferably about 0.1 to 0.5 μm. The amount of the ferromagnetic material contained in the magnetic toner is 60 parts by weight with respect to 100 parts by weight of the resin component. -110 weight part, Preferably it is 65-100 weight part with respect to 100 weight part of resin components.
[0059]
As the colorant used in the toner, conventionally known dyes and / or pigments can be used. For example, carbon black, phthalocyanine blue, peacock blue, permanent red, lake red, rhodamine lake, hand yellow, permanent yellow, benzidine yellow and the like can be mentioned. The content thereof is 0.1 to 20 parts by weight, preferably 0.5 to 20 parts by weight with respect to 100 parts of the binder resin, and 12 for improving the transparency of the OHP film on which the toner image is fixed. The amount is preferably not more than parts by weight, more preferably 0.5 to 9 parts by weight.
[0060]
As described above, according to the present invention, it is possible to efficiently obtain a toner product having a sharp particle size distribution with a weight average particle size of 10 μm or less, and in particular, a sharp product with a weight average particle size of 7 μm or less. A toner product having a particle size distribution can be obtained efficiently.
[0061]
【Example】
Next, the present invention will be described in more detail with reference to examples and comparative examples of the present invention.
Example 1
・ Styrene-butyl acrylate-divinylbenzene copolymer (monomer polymerization
(Weight ratio 80.0 / 19.0 / 1.0, weight average molecular weight = 350,000) 100 parts by weight
・ 100 parts by weight of magnetic iron oxide (average particle size 0.18 μm)
・ 2 parts by weight of nigrosine
・ Low molecular weight ethylene-propylene copolymer 4 parts by weight
The materials of the above formula were mixed well with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.), and then a twin-screw kneader (PCM-30 type, Ikegai Iron Works Co., Ltd.) set at a temperature of 150 ° C. Kneaded). The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for toner production.
[0062]
The obtained toner raw material was finely pulverized and classified by the apparatus system shown in FIG. The collision type airflow crusher 28 uses an apparatus having the configuration shown in FIG. 5, and the inclination of the major axis of the acceleration tube with respect to the vertical line (hereinafter referred to as the acceleration tube inclination) is about 0 ° (that is, substantially The collision member 51 shown in FIG. 6 was used. As the collision member 51, α = 55 °, β = 10 °, and an outer diameter (diameter) of 100 mm were used, and the shape of the crushing chamber 53 was a cylindrical shape having an inner diameter of 150 mm. As the first classifying means 22, a rotary air classifier having the configuration shown in FIGS. Diameter L of classification rotor 124₁Is 200 mm, the blade length L of the classification rotor 124₂Was 30 mm, and the angle θ formed by the straight line connecting the center of the classification rotor 124 and the tip of the blade and the blade was set to 45 °. The rotation speed of the classification rotor 124 was 2,500 rpm.
[0063]
In the present embodiment, first, a powder raw material made of coarsely pulverized material is firstly fed at a rate of 35.0 kg / h by a table-type first fixed quantity feeder 21 through a feed pipe 125 in FIG. Was supplied to the rotary air classifier 22 having the configuration shown in FIG. 1 and classified into coarse powder and fine powder. The coarse powder classified by the classifier was introduced into the collision-type airflow fine pulverizer 28 having the configuration shown in FIG. 5 through the coarse powder discharge hopper 132 and finely pulverized. The coarse powder supplied from the pulverized material supply pipe 41 of the pulverizer 28 has a pressure of 6.0 kg / cm.²(G), 6.0 Nm^ThreeAfter being pulverized using compressed air of / min, it is mixed with the powder raw material for toner production supplied at the raw material introduction section, and again introduced into the air classifier 22 as the first classification means, Closed circuit grinding was performed. On the other hand, the fine powder classified by the rotary airflow classifier 22 in the first classification step is collected by the cyclone 23 while being entrained by the suction air from the exhaust fan 131 and introduced into the second fixed quantity feeder 24. . At this time, the fine powder obtained by classification with the rotary air classifier 22 has a weight average diameter of 7.1 μm, 45% by number of particles having a particle size of 4.0 μm or less, and particles having a particle size of 10.8 μm or more. The particle size distribution was 3.0% by volume.
[0064]
Next, the fine powder obtained by classification by the rotary airflow classifier 22 of the first classifying means is introduced into the second fixed amount feeder 24, and 30.30 through the vibration feeder 25 and the nozzles 148 and 149. At a rate of 0 kg / h, the mixture was introduced into a three-division classifier 27 having the configuration of FIG. The classifier 27 uses the Coanda effect to classify into three types of particle sizes: coarse powder, medium powder, and fine powder.
Upon introduction into the three-class classifier 27, the suction force derived from the pressure reduction in the system due to the suction pressure reduction of the collection cyclones 29, 30 and 31 communicating with the discharge ports 158, 159 and 160 and the raw material supply nozzle 148 The compressed air from the attached injection feeder 32 was used. The introduced fine powder was classified into three types of coarse powder, medium powder and fine powder instantly for 0.1 seconds or less. Of the classified materials, the coarse powder was collected by the collection cyclone 29, and then introduced into the airflow fine pulverizer 28 described above, and again introduced into the pulverization step.
[0065]
The intermediate powder (classified product) classified in the second classification step has a weight average particle size of 6.9 μm, contains 25% by number of particles having a particle size of 4.0 μm or less, and a particle size of 10.08 μm. It had a sharp particle size distribution containing 1.3% by volume of the above particles, and had excellent performance as a classified product for toner. At this time, the ratio of the amount of the finally obtained classified product to the total amount of the charged powder raw material (namely, the classification yield) was 85%.
[0066]
The particle size distribution of the toner can be measured by various methods. In the present invention, the following measurement apparatus was used. That is, a Coulter Counter TA-II type or Coulter Multisizer II (both manufactured by Coulter, Inc.) was used as a measuring device. As the electrolyte solution, an approximately 1% NaCl aqueous solution was prepared using primary sodium chloride, and for example, ISOTONR-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkyl benzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolyte solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution in which the sample is suspended is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Using the measurement apparatus, a 100 μm aperture is used as an aperture, and the volume and number of toners are measured. Was calculated. Then, the weight-based weight average particle diameter obtained from the volume distribution according to the present invention was obtained.
[0067]
Example 2
Using the same toner raw material as in Example 1, fine pulverization and classification were performed in the same apparatus system. That is, the collision airflow pulverizer having the configuration shown in FIG. 5 was used, and pulverization was performed under the same apparatus conditions as in Example 1. The second classifying means 27 is the same as that used in Example 1. In addition, the same rotary air classifier as in Example 1 was used as the first classifying means, but the rotational speed of the classifying rotor was 3,100 rpm.
In this example, a powder raw material was supplied to the apparatus system at a rate of 32.0 kg / h, and fine powder having a weight average particle diameter of 6.4 μm was obtained by the first classification process and the pulverization process. Next, this fine powder is introduced into the second classifying means 27 at a rate of 25.0 kg / h via the second quantitative feeder 24, and the weight average particle diameter is 6.1 μm and the particle diameter is 4.0 μm or less. A classified product (medium powder) having a sharp particle size distribution containing 32% by number of particles and 0.5% by volume of particles having a particle size of 10.08 μm or more was obtained with a classification yield of 77%.
[0068]
Example 3
Using the same toner raw material as in Example 1, fine pulverization and classification were performed in the same apparatus system. That is, the collision airflow pulverizer having the configuration shown in FIG. 5 was used, and pulverization was performed under the same apparatus conditions as in Example 1. The second classifying means 27 is the same as in the first embodiment.ofA thing was used.
The first classification means 22 includes a diameter L of the classification rotor 124.₁Is 300mm,Feather length L₂Was 35 mm, and the angle θ between the straight line connecting the center of the classification rotor 124 and the tip of the blade and the blade was 60 °, and the rotation speed of the classification rotor 124 was 3,100 rpm.
In this embodiment, the above-mentioned apparatus system is used for the pulverized raw material at a rate of 32.0 kg / h.InThe fine powder having a weight average particle diameter of 5.9 μm was obtained by the first classification step and the pulverization step. Next, as a result of introducing this fine powder into the second classifying means 27 at a rate of 25.0 kg / h via the second constant amount feeder 24, a weight average particle size of 5.8 μm and a particle size of 4.0 μm or less. Thus, a classified product having a sharp particle size distribution containing no more than 37% by number of particles and containing particles having a particle size of 10.08 μm or more was obtained with a classification yield of 75%.
[0069]
Example 4
・ 100 parts by weight of unsaturated polyester resin
Copper phthalocyanine pigment (C.I.Pigment Blue 15) 4.5 parts by weight
Charge control agent (chromium salicylate complex) 4.0 parts by weight
The materials of the above formulation were mixed well with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.), and then a twin-screw kneader (PCM-30 type, Ikegai Iron Works Co., Ltd.) set at a temperature of 100 ° C. Kneaded). The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for toner production.
[0070]
Using the powder raw material obtained above, pulverization and classification were performed with the apparatus system shown in FIG.
For the collision-type airflow crusher 28, an apparatus having the configuration shown in FIG. As the second classifying means 27, the same one as in Example 1 was used. The first classifying means 22 is the same as that of the first embodiment, but the diameter L of the classifying rotor 124 is used.₁Is 200mm, the blade length L of the classification rotor 124₂And 30 mm and θ of 45 ° were used, and the classification rotor 124 was classified with a rotational speed of 3,500 rpm.
[0071]
In the present embodiment, the powder raw material made of coarsely pulverized material is shown in FIG. 3 through the supply pipe 125 at the rate of 28.0 kg / h by the table feeder. This was supplied to the rotary air classifier 22 having the above-described configuration and classified. The coarse powder classified by the classifier was introduced into the collision-type airflow pulverizer 28 having the configuration shown in FIG. 5 through the coarse powder discharge hopper 132. The coarse powder supplied from the material supply pipe 41 of the pulverizer 28 has a pressure of 6.0 kg / cm.²(G), 6.0 Nm^ThreeAfter being pulverized using compressed air of / min, the mixture was mixed with the powder raw material for toner supplied in the raw material introduction unit, and again introduced into the airflow classifier 22 and circulated to perform closed circuit pulverization. . The fine powder classified by the rotary air classifier 22 of the first classifying means is collected by the cyclone 23 while being accompanied by the suction air from the exhaust fan 131. The weight average particle size of the fine powder at this time was 7.0 μm.
[0072]
The obtained fine powder is introduced into the second classifying means 27 at a rate of 25.0 kg / h through the vibration feeder 25 and the nozzles 148 and 149 through the second fixed amount feeder 24, and the Coanda effect is obtained. The powder was classified into three types of coarse powder, medium powder and fine powder, and the medium powder was classified as a toner product.
[0073]
The resulting classified product has a weight average particle size of 6.5 μm, contains 27% by number of particles having a particle size of 4.0 μm or less, and 1.4% by volume of particles having a particle size of 10.08 μm or more. It had a sharp particle size distribution and had excellent performance as a classified product for toner. At this time, the ratio of the amount of the intermediate powder finally obtained to the total amount of the powder raw material charged (that is, the classification yield) was 80%.
[0074]
Example 5
Using the same toner raw material as in Example 4, fine pulverization and classification were performed in the same apparatus system. That is, the collision type airflow pulverizer having the configuration shown in FIG. 5 was used, and the second classification means 27 was the same as that of Example 1. Further, as the first classifying means, the rotary air classifier having the configuration shown in FIG. 4 similar to that of Example 4 was used, but the diameter L of the classifying rotor 124 was used.₁300mm, blade length L₂Is 35 mm and θ is 60 °, and the rotational speed of the classification rotor 124 is 3,500 r. p. m. It was.
In this example, the powder raw material was supplied to the apparatus system at a rate of 28.0 kg / h, and fine powder having a weight average particle diameter of 6.4 μm was obtained by the first classification process and the pulverization process. And as a result of introducing this fine powder into the 2nd classification means 27 at the rate of 25.0 kg / h via the 2nd fixed supply machine 24, the weight average particle diameter is 6.0 micrometers and the particle diameter is 4.0 micrometers or less. A classified product having a sharp particle size distribution containing 35% by number of particles and 0.2% by volume of particles having a particle size of 10.08 μm or more was obtained with a classification yield of 76%.
[0075]
Comparative Example 1
A material having the same formulation as in Example 1 was mixed well with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.), and then a twin-screw kneader (PCM-30 type, set at a temperature of 150 ° C., Kneaded by Ikekai Tekko Co., Ltd. The obtained kneaded product was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized product for toner production.
The obtained toner raw material was pulverized and classified by the apparatus system shown in FIG. However, the conventional crushing type airflow crusher shown in FIG.1 minuteA class means having the structure shown in FIG. 12 was used. The second classification means 27 used was the same as that in Example 1.
[0076]
In FIG. 12, the powder raw material introduced from the powder supply cylinder 280 together with the carrier air is introduced into a classification chamber 250 provided with an inclined classification plate 200 having a high central portion at the bottom thereof. , The powder raw material is swirled and flowed by the airflow that flows together, and is centrifuged into fine powder and coarse powder through the classification louver 290, and the fine powder is discharged from the fine powder discharge chute 220 provided at the center of the classification plate 200. The coarse powder is discharged from the coarse powder outlet 210 provided on the outer peripheral portion of the classification plate 200.
[0077]
In the present comparative example, the powder raw material is fed at a rate of 13.0 kg / h by the table type first fixed quantity feeder 21, and the airflow classifier shown in FIG. 12 through the powder feeder cylinder 280 by the injection feeder 35. And classified. The classified coarse powder is supplied through the coarse powder discharge hopper 230 from the pulverized material supply port 165 of the conventional collision-type airflow pulverizer 28 shown in FIG. 11, and the pressure is 6.0 kg / cm.²(G), 6.0 Nm^ThreeAfter being pulverized with compressed air of / min, the mixture was circulated through the air classifier again while mixing with the pulverized raw material for toner production supplied at the raw material introduction unit 37, and closed circuit pulverization was performed. First1 minuteThe fine powder classified by the classifying means was collected by the cyclone 23 while being accompanied by the suction air from the suction fan, and was introduced into the second fixed amount feeder 24. At this time, the fine powder has a weight average diameter of 7.1 μm, contains 57% by number of particles having a particle size of 4.0 μm or less, and a broad particle size distribution containing 8.0% by volume of particles having a particle size of 10.08 μm or more. Had.
[0078]
The obtained fine powder was introduced at a rate of 15.0 kg / h into the second classifying means 27 similar to that used in Example 1 through the second fixed amount feeder 24 and further through the vibration feeder 25.
As a result, a classified product having a weight average diameter of 6.9 μm, a particle size distribution containing 27% by number of particles having a particle size of 4.0 μm or less and 1.5% by volume of particles having a particle size of 10.08 μm or more ( (Medium powder) was obtained with a classification yield of 81%. Thus, compared with Example 1, it was inferior in classification and the grinding | pulverization processing efficiency.
[0079]
Comparative Example 2
Using the same toner raw material as in Example 1, fine pulverization and classification were performed in the same apparatus system. However, the collision type airflow crusher 28 has the conventional configuration shown in FIG. 11, the first classification means has the configuration shown in FIG. 12, and pulverizes under the same apparatus conditions as in Comparative Example 1. It was. The second classification means 27 used was the same as that in Example 1.
The powder raw material was supplied to the first classifying means 22 at a rate of 10.0 kg / h to obtain a fine powder having a weight average diameter of 6.3 μm. This fine powder is introduced into the second classifying means 27 at a rate of 12.0 kg / h, contains 33% by number of particles having a weight average diameter of 6.1 μm, a particle diameter of 4.0 μm or less, and a particle diameter of 10.08 μm. A classified product having a particle size distribution containing 0.5% by volume of the above particles was obtained with a classification yield of 70%. Thus, compared with Example 2, both classification and pulverization efficiency and classification efficiency were inferior.
[0080]
Comparative Example 3
A material having the same formulation as in Example 4 was thoroughly mixed with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.), and then a twin-screw kneader (PCM-30 type, set at a temperature of 100 ° C., Kneaded by Ikekai Tekko Co., Ltd. The obtained kneaded material was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized material as a powder raw material for toner production.
The obtained toner raw material was pulverized and classified by the apparatus system shown in FIG. However, a conventional collision type airflow crusher having the configuration shown in FIG.1 minuteA class means having the structure shown in FIG. 12 was used. The second classification means 27 used was the same as that in Example 1.
[0081]
In this comparative example, the pulverized raw material is fed at a rate of 12.0 kg / h by the table-type first fixed quantity feeder 21, and the air current classifier shown in FIG. 12 is passed through the powder feeder cylinder 280 by the injection feeder 35. Supplied. The coarse powder classified by the classifier is supplied from the pulverized material supply port 165 of the collision-type airflow pulverizer shown in FIG. 11 through the coarse powder discharge hopper 230, and the pressure is 6.0 kg / cm.²(G), 6.0 Nm^ThreeAfter being pulverized using compressed air of / min, it was circulated through the first classifying means 22 again while mixing with the powder raw material supplied at the raw material introduction part, and closed circuit pulverization was performed. On the other hand1 minuteThe fine powder classified in the classification process was collected by the cyclone 23 while being accompanied by the suction air from the exhaust fan, and was introduced into the second fixed amount feeder 24. In addition, the weight average diameter of the fine powder at this time was 7.0 μm.
[0082]
The obtained fine powder was introduced into the second classifying means 27 through the second fixed amount feeder 24 and further through the vibration feeder 25 at a rate of 14.0 kg / h. As a result, a classified product having a particle size distribution having a weight average diameter of 6.5 μm, containing 28% by number of particles having a particle size of 4.0 μm or less, and 1.6% by volume of particles having a particle size of 10.08 μm or more. A classification yield of 76% was obtained. Thus, compared with Example 4, it was inferior in classification and the grinding | pulverization processing efficiency.
[0083]
Example and Comparative Example System and Classification / Crushing Results

[0084]
【The invention's effect】
As described above, according to the method for producing a toner of the present invention, a toner having a small particle size with a sharp particle size distribution can be obtained with a high processing efficiency and a high classification yield. The problem of toner fusing, coarsening or agglomeration in the toner is effectively prevented, and wear on the device due to the toner component is effectively prevented, so that high quality toner can be produced continuously and stably. Can do.
In addition, according to the method for producing a toner of the present invention, compared to the conventional method, the image density is stable and high, excellent in durability, and excellent images free from image defects such as fogging and poor cleaning can be obtained. An excellent toner for developing an electrostatic image having a sharp predetermined particle size with a small particle size can be obtained at low cost.
In particular, according to the present invention, it is possible to efficiently obtain a toner having a sharp particle size distribution from a raw material having a weight average diameter of 10 μm or less, and further, from a raw material having a weight average diameter of 7 μm or less to a small particle diameter. A toner having a sharp particle size distribution can be obtained efficiently.
[Brief description of the drawings]
FIG. 1 is an example of a flowchart showing an outline of a toner manufacturing method of the present invention.
FIG. 2 is a schematic view showing an example of an apparatus system for carrying out the manufacturing method of the present invention.
FIG. 3 is a schematic cross-sectional view of a preferred embodiment of the first classifying means used in the production method of the present invention.
4 is an enlarged view and an enlarged side view of the horizontal rotary rotor in FIG. 3. FIG.
FIG. 5 is a schematic cross-sectional view of a preferred embodiment of a collision airflow crushing means used in the production method of the present invention.
6 is a cross-sectional view taken along line A-A ′ in FIG. 5;
7 is a cross-sectional view taken along line B-B ′ in FIG. 5;
8 is a cross-sectional view taken along C-C ′ in FIG. 5;
9 is an enlarged view of a collision member in FIG.
FIG. 10 is a schematic cross-sectional view of an example of a multi-division classifier used for the second classifying means.
FIG. 11 is a schematic sectional view of a conventional collision-type airflow crusher.
FIG. 12 is an example of an airflow classifier used for conventional first classifying means.
FIG. 13 is an example of a flowchart showing an outline of a conventional toner manufacturing method.
[Explanation of symbols]
21: First metering feeder
22: First classification means
23: Collection cyclone
24: Second metering machine
25: Vibration feeder
27: Second classification means
28: Crusher
29, 30, 31: Collection cyclone
32: Injection feeder
33: Product
34: Fine powder
35: Injection feeder
36: Supply pipe
37: Raw material introduction part
41: To-be-ground material supply pipe
42: Object to be crushed
43: Accelerating tube
44: Throat
45: High-pressure gas ejection nozzle
46: Ground supply port
47: High-pressure gas supply port
48: High-pressure gas chamber
49: High pressure gas inlet
50: Acceleration tube exit
51: Collision member
52, 52 ': collision surface
53: Crushing chamber
54: Side wall of grinding chamber
55: Crushing material outlet
91: Colliding member support
92: High-pressure gas introduction pipe
101: Ground supply port
121: Main body casing
122: Classification room
123: Information room
124: Classification rotor
125: Raw material inlet
126: Air inlet
128: Frequency converter
129: Fine powder discharge pipe
130: Fine powder recovery means
131: Suction fan
132: Hopper
133: Rotary valve
134: Feather
148, 149: Raw material supply pipe
158, 159, 160: outlet
161: High-pressure gas supply nozzle
162: Accelerating tube
163: Acceleration tube exit
164: Colliding member
165: Grinding raw material supply port
166: Colliding surface
167: Ground product outlet
168: Grinding chamber
200: Classification board
201: Classifier body casing
210: Coarse powder outlet
220: Fine powder discharge chute
230: Coarse powder discharge hopper
240: upper part of the guide tube
250: Classification room
254: Guide tube
260: Top cover
270: Classification lower casing
280: Powder supply cylinder
290: Classification louver

Claims (1)

First, a powder raw material comprising a coarsely pulverized product obtained by melt-kneading a mixture containing at least a binder resin and a colorant, cooling the obtained kneaded product, and then pulverizing the cooled product by a pulverizing means, Introduced into the first classifying step using a rotary airflow classifying means having a horizontal rotary rotor and classified into fine powder and coarse powder, and then the classified fine powder was introduced into the second classifying step and classified to toner In order to obtain a classified product for producing the pulverized product, and to use the coarse powder classified in the first classifying step as the material to be pulverized, and to finely pulverize the material to be pulverized and the acceleration tube for accelerating the material to be pulverized by high-pressure gas and a grinding chamber, in the grinding chamber collision member with collision surface provided opposite to the opening surface of the outlet of the accelerating tube is provided, the throat portion of the acceleration tube accelerates pipe the grinding object There is an object supply port for supplying to the product, and the collision surface protrudes from the center. And a side wall for further crushing the object to be crushed by the collision member into the crushing chamber by collision. A method for producing a toner, which is introduced into a collision-type airflow crushing means, finely pulverized, the finely pulverized product is mixed into the powder raw material, reintroduced into the first classification step, and circulated. The rotating rotor has a plurality of blades arranged at regular intervals on the same circumference, and each blade forms an angle θ of 35 to 65 ° with respect to a straight line connecting the center of the rotating rotor and the tip of the blade. The diameter L ₁ is 100 to 1,000 mm , the blade length L ₂ is ₁₀ to 100 mm, and the horizontal rotary rotor is rotated at 1,000 to 8,000 r . p. m. and rotated at and performing classified Method of manufacturing a toner.

Images