JP4140193B2 - Toner for developing electrostatic latent image, method for producing the same, and image forming method - Google Patents

Description

【０１８５】
【化２】

【０１８６】
上記化合物の添加量は、トナー全体に対し１〜３０質量％、好ましくは２〜２０質量％、さらに好ましくは３〜１５質量％である。
【０１８７】
尚、本発明において、「破砕強度指数」とは、トナー粒子の破砕されやすさを示す指標であって、具体的には、下記の方法により求められる指数をいう。
【０１８８】
（方法）
トナー（試料）３０ｇと、ガラスビーズ「ＧＢ５０３Ｍ」（東芝バロティーニ社製，粒子径：２ｍｍ）１００ｇとを２リットルのポリエチレンポットに入れ、タービュラーミキサーにより６０秒間混合攪拌した後、３３０メッシュの試験篩でガラスビーズを分離除去する。
【０１８９】
そして、混合攪拌前後において、全トナー粒子中における２〜４μｍの小粒子の個数割合（％）を測定し、下記の式により算出する。
【０１９０】
破砕強度指数＝（Ｎ−Ｎ₀）／６０
（式中、Ｎは、混合攪拌後における２〜４μｍの小粒子の個数％であり、Ｎ₀は、混合攪拌前における２〜４μｍの小粒子の個数％である。）
なお、「小粒子の個数％」は、コールターマルチサイザーを用いて測定された値である。具体的には、コールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機製）、パーソナルコンピューターを接続して使用する。前記コールターマルチサイザーにおけるアパーチャーとしては１００μｍのものを用いて、２μｍ以上（例えば２〜４０μｍ）のトナーの体積分布を測定して算出した。
【０１９１】
請求項１６に係る本発明のトナーは、樹脂と離型剤と着色剤を含有するトナーであって、上記定義による破砕強度指数が０．１〜０．８である点に特徴を有する。
【０１９２】
破砕強度指数が０．８を超えるトナーは、十分な耐破砕性を有することができず、そのようなトナーを長期にわたり画像形成に供すると、破砕によって生じた微粉により、フィルミング、カブリ、キャリアスペントなどが発生する。
【０１９３】
一方、破砕強度指数が０．１未満であるトナーは、最低定着温度が高くなる傾向があり、複写機の小型化および低消費電力化などの要請に十分に応えることができない。
【０１９４】
本発明のトナーでは、ミニエマルジョン重合法により樹脂粒子中に上記離型剤を内包させ、着色粒子とともに塩析、融着させて調製することが好ましい。
【０１９５】
本発明のトナーには、流動性の改良やクリーニング性の向上などの目的で、いわゆる外添剤を添加して使用することができる。これら外添剤としては特に限定されるものでは無く、種々の無機微粒子、有機微粒子及び滑剤を使用することができる。
【０１９６】
外添剤として使用できる無機微粒子としては、従来公知のものを挙げることができる。具体的には、シリカ微粒子、チタン微粒子、アルミナ微粒子等を好ましく用いることができる。これら無機微粒子は疎水性であることが好ましい。
【０１９７】
シリカ微粒子の具体例としては、日本アエロジル社製の市販品Ｒ−８０５、Ｒ−９７６、Ｒ−９７４、Ｒ−９７２、Ｒ−８１２、Ｒ−８０９、ヘキスト社製のＨＶＫ−２１５０、Ｈ−２００、キャボット社製の市販品ＴＳ−７２０、ＴＳ−５３０、ＴＳ−６１０、Ｈ−５、ＭＳ−５等が挙げられる。
【０１９８】
チタン微粒子の具体例としては、例えば、日本アエロジル社製の市販品Ｔ−８０５、Ｔ−６０４、テイカ社製の市販品ＭＴ−１００Ｓ、ＭＴ−１００Ｂ、ＭＴ−５００ＢＳ、ＭＴ−６００、ＭＴ−６００ＳＳ、ＪＡ−１、富士チタン社製の市販品ＴＡ−３００ＳＩ、ＴＡ−５００、ＴＡＦ−１３０、ＴＡＦ−５１０、ＴＡＦ−５１０Ｔ、出光興産社製の市販品ＩＴ−Ｓ、ＩＴ−ＯＡ、ＩＴ−ＯＢ、ＩＴ−ＯＣ等が挙げられる。
【０１９９】
アルミナ微粒子の具体例としては、例えば、日本アエロジル社製の市販品ＲＦＹ−Ｃ、Ｃ−６０４、石原産業社製の市販品ＴＴＯ−５５等が挙げられる。
【０２００】
外添剤として使用できる有機微粒子としては、数平均一次粒子径が１０〜２０００ｎｍ程度の球形の微粒子を挙げることができる。かかる有機微粒子の構成材料としては、ポリスチレン、ポリメチルメタクリレート、スチレン−メチルメタクリレート共重合体などのを挙げることができる。
【０２０１】
外添剤の添加量としては、トナーに対して０．１〜５質量％程度であることが好ましい。
【０２０２】
外添剤を添加するために使用される装置としては、タービュラーミキサー、ヘンシエルミキサー、ナウターミキサー、Ｖ型混合機などの種々の公知の混合装置を挙げることができる。
【０２０３】
本発明のトナーの粒径は、個数平均粒径で２〜１０μｍであることが好ましく、更に好ましくは３〜８μｍとされる。この粒径は、トナーの製造方法において、凝集剤（塩析剤）の濃度や有機溶媒の添加量、融着時間、重合体の組成によって制御することができる。
【０２０４】
個数平均粒径が２〜１０μｍであることにより、定着工程において、飛翔して加熱部材に付着しオフセットを発生させる付着力の大きいトナー微粒子が少なくなり、また、転写効率が高くなってハーフトーンの画質が向上し、細線やドット等の画質が向上する。
【０２０５】
トナーの個数平均粒径は、コールターカウンターＴＡ−II、コールターマルチサイザー、ＳＬＡＤ１１００（島津製作所社製：レーザー回折式粒径測定装置）等を用いて測定することができる。
【０２０６】
本発明においては、コールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機社製）、パーソナルコンピューターを接続して使用した。前記コールターマルチサイザーにおけるアパーチャーとしては、１００μｍのものを用いて、２μｍ以上（例えば２〜４０μｍ）のトナーの体積分布を測定して粒度分布および平均粒径を算出した。
【０２０７】
本発明のトナーの形状係数は、下記式により示されるものであり、トナー粒子の丸さの度合いを示す。
【０２０８】
形状係数＝（（最大径／２）²×π）／投影面積
ここに、最大径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。また、投影面積とは、トナー粒子の平面上への投影像の面積をいう。本発明では、この形状係数は、走査型電子顕微鏡により２０００倍にトナー粒子を拡大した写真を撮影し、ついでこの写真に基づいて「ＳＣＡＮＮＩＮＧ ＩＭＡＧＥ ＡＮＡＬＹＺＥＲ」（日本電子社製）を使用して写真画像の解析を行うことにより測定した。この際、１００個のトナー粒子を使用して本発明の形状係数を上記算出式にて測定したものである。
【０２０９】
形状係数が１．０〜１．６の範囲にあるトナー粒子の割合が６５個数％以上であることが望ましい。
【０２１０】
本発明のトナーとしては、トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおいて、最頻階級に含まれるトナー粒子の相対度数（ｍ１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ２）との和（Ｍ）が７０％以上であるトナーであることが好ましい。
【０２１１】
相対度数（ｍ１）と相対度数（ｍ２）との和（Ｍ）が７０％以上であることにより、トナー粒子の粒度分布の分散が狭くなるので、当該トナーを画像形成工程に用いることにより選択現像の発生を確実に抑制することができる。
【０２１２】
本発明において、前記の個数基準の粒度分布を示すヒストグラムは、自然対数ｌｎＤ（Ｄ：個々のトナー粒子の粒径）を０．２３間隔で複数の階級（０〜０．２３：０．２３〜０．４６：０．４６〜０．６９：０．６９〜０．９２：０．９２〜１．１５：１．１５〜１．３８：１．３８〜１．６１：１．６１〜１．８４：１．８４〜２．０７：２．０７〜２．３０：２．３０〜２．５３：２．５３〜２．７６・・・）に分けた個数基準の粒度分布を示すヒストグラムであり、このヒストグラムは、下記の条件に従って、コールターマルチサイザーにより測定されたサンプルの粒径データを、Ｉ／Ｏユニットを介してコンピュータに転送し、当該コンピュータにおいて、粒度分布分析プログラムにより作成されたものである。
【０２１３】
測定条件
１：アパーチャー：１００μｍ
２：サンプル調製法：電解液〔ＩＳＯＴＯＮ Ｒ−１１（コールターサイエンティフィックジャパン社製）〕５０〜１００ｍｌに界面活性剤（中性洗剤）を適量加えて撹拌し、これに測定試料１０〜２０ｍｇを加える。この系を超音波分散機にて１分間分散処理することにより調製する。
【０２１４】
トナー粒子については、形状係数の変動係数が１６％以下であり、個数粒度分布における個数変動係数が２７％以下であるトナー粒子から構成されるトナーを使用することで、現像性、細線再現性に優れ、安定したクリーニング性を長期にわたって形成することができる。
【０２１５】
さらに本発明者等は、個々のトナー粒子の微小な形状に着目して検討を行った結果、現像装置内部において、トナー粒子の角部分の形状が変化して丸くなり、その部分がブレード摩耗を発生させていることが判明した。この理由については明確ではないが、角部分にはストレスが加わりやすく、この部分のブレード摩耗を促進させると推定した。
【０２１６】
又、摩擦帯電によってトナー粒子に電荷を付与する場合には、特に角部分では電荷が集中しやすくなり、トナー粒子の帯電が不均一になりやすいと推定される。
【０２１７】
即ち、角がないトナー粒子の割合を５０個数％以上とすることが好ましい。さらには個数粒度分布における個数変動係数を２７％以下に制御されたトナー粒子から構成されるトナーを使用することによっても、現像性、細線再現性に優れ、高画質な画像を長期にわたって形成することができることを見出した。
【０２１８】
さらに、トナーを特定の形状としてその形状を揃えた場合にも、ブレード摩耗が減少し、且つ帯電量分布がシャープとなることが判明した。
【０２１９】
すなわち、形状係数が１．２〜１．６の範囲にあるトナー粒子の割合が６５個数％以上であり、さらには形状係数の変動係数が１６％以下であるトナーを使用することでも、現像性、細線再現性に優れ、高画質な画像を長期にわたって形成することができる。
【０２２０】
尚、本発明のトナーの形状係数の変動係数は下記式から算出される。
変動係数（％）＝（Ｓ／Ｋ）×１００
式中、Ｓは１００個のトナー粒子の形状係数の標準偏差、Ｋは形状係数の平均値を示す。
【０２２１】
トナーの個数粒度分布における個数変動係数は下記式から算出される。
個数変動係数（％）＝（Ｓ／Ｄｎ）×１００
式中、Ｓは個数粒度分布における標準偏差を示し、Ｄｎは個数平均粒径（μｍ）を示す。
【０２２２】
本発明の角がないトナー粒子とは、電荷の集中するような突部またはストレスにより摩耗しやすいような突部を実質的に有しないトナー粒子を言い、具体的には以下のトナー粒子を角がないトナー粒子という。すなわち、図１（ａ）、（ｂ）、（ｃ）に示すように、トナー粒子の長径をＬ、Ｌ／１０を半径Ｒとする円で、トナー粒子周囲線に対し１点で内側に接しつつ内側をころがした場合に、全く円がトナーの外側に実質的にはみださない場合を角がないトナー粒子という。実質的にはみ出さない場合とは、はみ出す円が存在する突起が１箇所以下をいう。また、トナー粒子の長径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。
【０２２３】
角がないトナーの測定は次のようにして行った。先ず、走査型電子顕微鏡によりトナー粒子を拡大した写真を撮影し、さらに拡大して１５，０００倍の写真像を得る。次いでこの写真像について前記の角の有無を測定する。この測定を１００個のトナー粒子について行った。
【０２２４】
本発明のトナーは、一成分現像剤でも二成分現像剤として用いてもよい。
一成分現像剤として用いる場合は、非磁性一成分現像剤、あるいはトナー中に０．１〜０．５μｍ程度の磁性粒子を含有させ磁性一成分現像剤としたものがあげられ、いずれも使用することができる。
【０２２５】
また、キャリアと混合して二成分現像剤として用いることができる。この場合は、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いることが出来る。特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５〜１００μｍ、より好ましくは２５〜８０μｍのものがよい。
【０２２６】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０２２７】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン−アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレン−アクリル系樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０２２８】
本発明のトナーは、トナー像が形成された転写材（画像形成支持体、転写紙等ともいう）を、定着装置を構成する加熱ローラーと加圧ローラーとの間に通過させて定着する工程を含む画像形成方法に好適に使用される。
【０２２９】
次に、これに限定されるものではないが、図２に本発明に係わる画像形成装置の一例を示す構成図の例を挙げ、本発明の画像形成方法の説明をする。
【０２３０】
図２において、図示しない原稿読み取り装置にて読み取った情報に基づき、半導体レーザ光源１１から露光光が発せられる。これをポリゴンミラー１２により、図２の紙面と垂直方向に振り分け、画像の歪みを補正するｆθレンズ１３を介して、感光体面上に照射され静電潜像を作る。感光体１４は、あらかじめ帯電器１５により一様帯電され、像露光のタイミングにあわせて時計方向に回転を開始している。
【０２３１】
感光体面上の静電潜像は、反転現像条件の下で現像器１６により現像され、形成された現像像はタイミングを合わせて搬送されてきた転写体１８に転写器１７の作用により転写される。さらに感光体１４と転写体１８は分離器（分離極）１９により分離されるが、現像像は転写体１８に転写担持されて、定着器４０へと導かれ定着される。
【０２３２】
感光体面に残留した未転写のトナー等は、クリーニングブレード方式のクリーニング器２１にて清掃され、帯電前露光（ＰＣＬ）２２にて残留電荷を除き、次の画像形成のため再び帯電器１５により、一様帯電される。
【０２３３】
尚、転写体Ｐは代表的には普通紙であるが、現像後の未定着像を転写可能なものなら、特に限定されず、ＯＨＰ用のＰＥＴベース等も無論含まれる。
【０２３４】
又、クリーニングブレード２３は、厚さ１〜３０ｍｍ程度のゴム状弾性体を用い、材質としてはウレタンゴムが最も良く用いられる。
【０２３５】
また、本発明の画像形成装置において、感光体と、少なくとも帯電器、像露光器、現像器、転写器、クリーニング器の何れかを一体的に構成したプロセスカートリッジを構成し、画像形成装置本体に着脱自在に取り付けるのも好ましい態様である。
【０２３６】
【実施例】
次に、本発明の効果を具体的に説明する為、実施例にて説明するが、本発明の態様は無論これらに限定されるものではない。
【０２３７】
ステアリン酸カルシウムの製造例
ステアリン酸カルシウム１〜５
固形分濃度１２．６質量％、ＢＥＴ比表面積１０ｍ²／ｇの石灰乳スラリーを準備した。この石灰乳スラリーを、ダイノーミル（シンマーエンタープライゼズ社製：ＫＤＬ−ｐｉｌｏｔ型）で湿式磨砕し、ＢＥＴ比表面積が２０ｍ²／ｇ、沈降体積８０ｍｌ／６０分の石灰乳スラリーとした。この石灰乳スラリーを固形分濃度４０％になるように脱水した。
【０２３８】
一方、容量３リットルのニーダー中に１００℃に加熱溶融したステアリン酸（中和価１９７）５７０ｇを用意し、この溶融したステアリン酸に準備した固形分濃度４０％の石灰乳２２２ｇと水９７．６ｇを添加した。この配合割合は、換算すると、高級脂肪酸／Ｃａ（ＯＨ）₂／水（モル比）＝２／１．２／１２．８である。この状態で５〜３０分間混合し、ステアリン酸と水酸化カルシウムの反応を終了させた。
【０２３９】
反応終了物を１００℃で減圧乾燥し、カルシウム石鹸を得た。得られたカルシウム石鹸をＩＲ分析したところ、１７００ｃｍ^-1のカルボキシル基のピークが、１６００ｃｍ^-1のカルボキシレートのピークに変化しており、ステアリン酸カルシウムが形成されていることが確認された。反応時間と減圧乾燥時間を変えて、表１にしめすステアリン酸カルシウム１〜５を得た。
【０２４０】
ステアリン酸カルシウム６
ステアリン酸カルシウムの１〜５の製造において、ステアリン酸５７０ｇの代わりにステアリン酸３９９ｇとパルミチン酸１７１ｇとした以外は同様にして表１にしめすステアリン酸カルシウム６を得た。
【０２４１】
【表１】

【０２４２】
無機／有機複合粒子の製造例
平均粒子径１．０μｍのスチレン−アクリル有機微粒子（電気抵抗６．６×１０¹³Ω・ｃｍ）１００ｇに対して一次粒子径が３０ｎｍの表面を酸化スズ処理した酸化チタン粒子商品名ＥＴ−３００Ｗ（石原産業社製）を４０ｇ添加しタービュラミキサにて混合した。ついで、粉砕機を改造したハイブリダイザ（奈良機械製作所社製）にて周速１００ｍ／ｓｅｃの条件で３分間処理して有機微粒子表面に酸化チタンが固着された無機／有機複合微粒子を作製した。これを「無機／有機複合微粒子１」とする。
【０２４３】
無機／有機複合微粒子１の電気抵抗は４．８×１０⁸Ω・ｃｍであった。
トナー用樹脂粒子の製造例
（ラテックス：１ＨＭＬ）
（１）核粒子の調製（第１段重合）
撹拌装置、温度センサー、冷却管、窒素導入装置を取り付けた５０００ｍｌのセパラブルフラスコに、アニオン系界面活性剤（ドデシルスルフォン酸ナトリウム：ＳＤＳ）７．０８ｇをイオン交換水３０１０ｇに溶解させた界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの撹拌速度で撹拌しながら、内温を８０℃に昇温させた。
【０２４４】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）９．２ｇをイオン交換水２００ｇに溶解させた開始剤溶液を添加し、温度を７５℃とした後、スチレン７０．１ｇ、ｎ−ブチルアクリレート１９．９ｇ、メタクリル酸１０．９ｇからなる単量体混合液を１時間かけて滴下し、この系を７５℃にて２時間にわたり加熱、撹拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（１Ｈ）」とする。
【０２４５】
（２）中間層の形成（第２段重合）
撹拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．４ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル５．６ｇからなる単量体混合液に、前記式１９）で表される化合物（以下、「例示化合物（１９）」という）７２．０ｇを添加し、８０℃に加温し溶解させて単量体溶液を調製した。
【０２４６】
一方、アニオン系界面活性剤（ＳＤＳ）１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、核粒子の分散液である前記ラテックス（１Ｈ）を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム−テクニック社製）により、前記例示化合物（１９）の単量体溶液を混合分散させ、均一な分散粒子径（２８４ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２４７】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を８０℃にて３時間にわたり加熱撹拌することにより重合（第２段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを「ラテックス（１ＨＭ）」とする。
【０２４８】
（３）外層の形成（第３段重合）
上記のようにして得られたラテックス（１ＨＭ）に、重合開始剤（ＫＰＳ）７．４ｇをイオン交換水２００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン３００ｇ、ｎ−ブチルアクリレート９５ｇ、メタクリル酸１５．３ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル１０．４ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱撹拌することにより重合（第３段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層に例示化合物（１９）が含有されている複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（１ＨＭＬ）」とする。
【０２４９】
このラテックス（１ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１３，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の個数平均粒径は１０２ｎｍであった。
【０２５０】
〔複合樹脂粒子の調製例２〕
（１）核粒子の調製（第１段重合）：
撹拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．４ｇからなる単量体混合液に、前記式１６）で表される化合物「例示化合物（１６）と記す」７２．０ｇを添加し、８０℃に加温し溶解させて単量体溶液を調製した。
【０２５１】
一方、アニオン系界面活性剤（ＳＤＳ）１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム−テクニック社製）により、前記例示化合物（１６）の単量体溶液を混合分散させ、均一な分散粒子径（２６８ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２５２】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を８０℃にて３時間にわたり加熱撹拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（２Ｈ）」とする。
【０２５３】
（２）外層の形成（第２段重合）：
上記のようにして得られたラテックス（２Ｈ）に、重合開始剤（ＫＰＳ）１４．８ｇをイオン交換水４００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン６００ｇ、ｎ−ブチルアクリレート１９０ｇ、メタクリル酸３０．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル２０．８ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱撹拌することにより重合（第２段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、低分子量樹脂からなる外層とを有し、前記中心部に例示化合物（１６）が含有されている複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（２ＨＬ）」とする。
【０２５４】
このラテックス（２ＨＬ）を構成する複合樹脂粒子は、１６８，０００および１１，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１２６ｎｍであった。
【０２５５】
〔着色粒子の製造例１〜４〕
ｎ−ドデシル硫酸ナトリウム５９．０ｇをイオン交換水１６００ｍｌに撹拌溶解した。この溶液を撹拌しながら、カーボンブラック「リーガル３３０」（キャボット社製）４２０．０ｇを徐々に添加し、次いで、「クレアミックス」（エム−テクニック社製）を用いて分散処理することにより、着色剤粒子の分散液（以下、「着色剤分散液」という）を調製した。この着色剤分散液における着色剤粒子の粒子径を、電気泳動光散乱光度計「ＥＬＳ−８００」（大塚電子社製）を用いて測定したところ、重量平均粒子径で９８ｎｍであった。
【０２５６】
複合樹脂粒子の調製例１で得られたラテックス（１ＨＭＬ）４２０．７ｇ（固形分換算）と、イオン交換水９００ｇと、着色剤分散液１６６ｇとを、温度センサー、冷却管、窒素導入装置、撹拌装置、粒径および形状のモニタリング装置を取り付けた反応容器に入れ撹拌した。内温を３０℃に調整した後、この溶液に５モル／リットルの水酸化ナトリウム水溶液を加えてｐＨを１１．０に調整した。
【０２５７】
次いで、塩化マグネシウム６水和物１２．１ｇをイオン交換水１０００ｍｌに溶解した水溶液を、撹拌下、３０℃にて１０分間かけて添加した。３分間放置した後に昇温を開始し、この系を６〜１０分間かけて９０±３℃まで昇温した（昇温速度＝１０℃／分）。その状態で、「コールターカウンターＴＡ−II」にて会合粒子の粒径を測定し、体積平均粒径が５．５μｍになった時点で、塩化ナトリウム８０．４ｇをイオン交換水１０００ｍｌに溶解した水溶液を添加して粒子成長を停止させ、さらに、熟成処理として液温度８５±２℃にて０．５〜１５時間にわたり加熱撹拌することにより融着を継続させた。その後、８℃／分の条件で３０℃まで冷却し、塩酸を添加してｐＨを２．０に調整し、撹拌を停止した。生成した会合粒子をヌッチェを用いて濾過し、イオン交換水で繰り返し洗浄し、その後、フラッシュジェットドライヤーを用いて吸気温度６０℃にて乾燥させ、ついで流動層乾燥機を用いて６０℃の温度で乾燥させ、離型剤として例示化合物（１９）を含有する着色粒子を得た。前記塩析／融着段階および形状制御工程のモニタリングにおいて、撹拌回転数、および加熱時間を制御することにより、形状および形状係数の変動係数を制御し、粒径および粒度分布の変動係数を任意に調整して、表２に示す形状特性および粒度分布特性からなる着色粒子１〜４を得た。
【０２５８】
〔着色粒子の製造例５〜８〕
ラテックス（１ＨＭＬ）に代えて、複合樹脂粒子の調製例２で得られたラテックス（２ＨＬ）４２０．７ｇ（固形分換算）を使用し、熟成処理時間を変更したこと以外は着色粒子製造例１〜４と同様にして、表２に示す形状特性および粒度分布特性からなる着色粒子５〜８を得た。
【０２５９】
【表２】

【０２６０】
以上のようにして得られた着色粒子１〜８の各々に、疎水性シリカ（数平均一次粒子径＝１０ｎｍ、疎水化度＝６３）を１．０質量％となる割合で添加するとともに、疎水性酸化チタン（数平均一次粒子径＝２５ｎｍ、疎水化度＝６０）を０．８質量％となる割合でそれぞれ添加し、ヘンシェルミキサーにより混合した。
【０２６１】
さらに、表３に示すステアリン酸カルシウム０．０１質量％、無機／有機複合微粒子あるいは、チタン酸ストロンチウムをそれぞれ１質量％添加し、ヘンシェルミキサーにより混合し、トナー１〜１２を作製した。
【０２６２】
なお、ステアリン酸カルシウムを添加しないトナーを比較用トナー１とする。さらに、比較用として、ステアリン酸亜鉛（日本油脂社製：ジンクステアレートＤ）を添加したものを比較用トナー２とする。
【０２６３】
なお、これらの着色粒子について、外部添加剤の添加によっては、その形状および粒径は変化しない。
【０２６４】
【表３】

【０２６５】
キャリアの作製
フェライト芯材粒子の製造
ＭｎＯを２２ｍｏｌ％、Ｆｅ₂Ｏ₃を７８ｍｏｌ％を、湿式ボールミルで２時間粉砕、混合し乾燥させた後に、９００℃で２時間保持することにより仮焼成し、これをボールミルで３時間粉砕しスラリー化した。分散剤及びバインダーを添加し、スプレードライヤーにより造粒、乾燥し、その後１２００℃、３時間本焼成を行い、平均グレイン径５．２μｍ、抵抗４．３×１０８のフェライト芯材粒子を得た。
【０２６６】
樹脂被覆
まず、界面活性剤として炭素数１２のアルキル基を有するベンゼンスルホン酸ナトリウムを用いた水溶液媒体中の濃度を０．３質量％とした乳化重合法により、シクロヘキシルメタクリレート／メチルメタクリレート（共重合比５／５）の共重合体を合成し、体積平均一次粒径０．１μｍ、重量平均分子量（Ｍｗ）２００，０００、数平均分子量（Ｍｎ）９１，０００、Ｍｗ／Ｍｎ＝２．２、軟化点温度（Ｔｓｐ）２３０℃及びガラス転移温度（Ｔｇ）１１０℃樹脂微粒子を得た。なお、前記樹脂微粒子は、乳化状態において、水と共沸し、残存モノマー量を５１０ｐｐｍとした。
【０２６７】
次に、フェライト芯材粒子１００質量部と、前記樹脂微粒子２質量部とを、撹拌羽根付き高速撹拌混合機に投入し、１２０℃で３０分間撹拌混合して、機械的衝撃力の作用を使用して体積平均粒径６１μｍの樹脂被覆キャリアを得た。
【０２６８】
現像剤の製造
外部添加剤が添加された着色粒子（トナー）の各々と、キャリアとを混合し、トナー濃度が６質量％の現像剤を調製した。これらの現像剤を、着色粒子１〜１２、比較用着色粒子１〜２に対応して、現像剤１〜１２、比較用現像剤１〜２とする。
【０２６９】
感光体の製造
ポリアミド樹脂アミランＣＭ−８０００（東レ社製）３０ｇをメタノール９００ｍｌ、１−ブタノール１００ｍｌの混合溶媒中に投入し５０℃で加熱溶解した。この液を外径６０ｍｍ、長さ３６０ｍｍの円筒状アルミニウム導電性支持体上に塗布し、０．５μｍ厚の中間層を形成した。
【０２７０】
次に、シリコーン樹脂ＫＲ−５２４０（信越化学社製）１０ｇを酢酸ｔ−ブチル１０００ｍｌに溶解し、これにＹ−ＴｉＯＰｃ（特開昭６４−１７０６６号記載、図１）１０ｇを混入しサンドミルを用いて２０時間分散し、電荷発生層塗工液を得た。この液を用いて、前記中間層上に塗布し、０．３μｍ厚の電荷発生層を形成した。
【０２７１】
次に、ＣＴＭ（Ｔ−１：Ｎ−（４−メチルフェニル）−Ｎ−｛４−（β−フェニルスチリル）フェニル｝−ｐ−トルイジン）１５０ｇと粘度平均分子量２万のポリカーボネート樹脂ユーピロンＺ−２００（三菱ガス化学社製）２００ｇを１、２−ジクロロエタン１０００ｍｌに溶解し、電荷輸送層塗工液を得た。この液を用いて、前記電荷発生層上に円形スライドホッパーにて塗布を行った後、１００℃で１時間乾燥し、２２μｍ厚の電荷輸送層を形成した。このようにして中間層、電荷発生層、電荷輸送層からなる感光体（Ｐ１）を得た。ついで、感光体（Ｐ１）の表面に、ＣＴＭ（Ｔ−１）３０ｇと粘度平均分子量８万のポリカーボネート樹脂ユーピロンＺ−８００（三菱ガス化学社製）ポリカーボネート樹脂５０ｇを１，２−ジクロロエタン１０００ｍｌに溶解した塗工液を用いて、前記電荷輸送層上に円形スライドホッパーにて塗布を行った後、１００℃で１時間乾燥し、５μｍ厚のオーバーコート層を形成し、感光体（Ｐ２）を得た。
【０２７２】
実施例１〜１２および比較例１及び２
現像剤１〜１２、比較用現像剤１、２を用い、市販のデジタル複写機コニカ社製Ｓｉｔｉｏｓ Ｋｏｎｉｃａ７０３０に感光体（Ｐ２）を搭載した改造機を用い、高温高湿環境下（温度３３℃、相対湿度８０％）において、画素率が１５％の画像を連続して３０万枚形成する実写テストを行うことにより、ブレード摩耗量、スリ抜け、画像ボケ、画像濃度の環境依存性について評価した。
【０２７３】
尚、上記現像剤Ｎｏに対応させて、実施例１〜１２および比較例１及び２とした。
【０２７４】
ブレード摩耗量
１０万枚印字後、クリーニングブレードをクリーニング装置より取り外し、レーザー顕微鏡で摩耗により消失した部分を測長した。減耗量１０μｍ以内であれば、問題ないレベルである。
【０２７５】
スリ抜け
画像白地部にクリーニング装置から感光体上にトナーがスリ抜け、画像汚れとして検知された枚数で評価した。
【０２７６】
画像ボケ
画像全面に文字サイズ５ポイントの文字画像を形成し、局所的に画像がボケる、もしくはトナーが画像周辺に滲む部分が検知されるまでの枚数にて評価した。
【０２７７】
画像濃度の環境依存性
マクベス反射濃度計にてソリッド画像部の最高画像濃度を測定した。高温高湿環境（３３℃ ８０％ＲＨ）と低温低湿環境（１０℃ ２０％ＲＨ）の画像濃度の差が０．０５未満を「◎」、０．０５〜０．１を「○」、０．１以上を「×」とした。
【０２７８】
結果を表４に示す。
【０２７９】
【表４】

【０２８０】
本発明内の実施例１〜１２は何れの特性も問題がないが、本発明外の比較例１又は２は何れの特性も問題があることがわかる。
【０２８１】
【発明の効果】
本発明により、繰り返し使用時における感光体自体及びそれに作用する静電潜像現像用トナーやクリーニング装置の耐久性を上げる方法を提供することが出来る。より具体的にはクリーニングブレードの摩耗、クリーニング時の感光体面でのトナーすり抜け或いはトナー固着による画像ボケ等を無くし、使用時の温湿度環境による画像濃度の変動を無くした静電潜像現像用トナーとその製造方法及びそれを用いた画像形成方法或いは画像形成装置を提供することが出来る。
【図面の簡単な説明】
【図１】角がないトナー粒子を説明する図。
【図２】画像形成装置の構成図。
【符号の説明】
１４ 感光体
１５ 帯電器
１６ 現像器
１７ 転写器
１８ 転写体
４０ 定着器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic latent image developing toner, a manufacturing method thereof, and an image forming method or an image forming apparatus using the same.
[0002]
[Prior art]
Today, in most copying machines and printers that require high-speed and high-quality images, image formation is performed by an electrophotographic system using electrostatic latent image developing toner.
[0003]
This is because the electrophotographic method is capable of forming high-quality images at high speed and is stable enough to withstand long-term use. It is actively done.
[0004]
Among them, a major theme is the pursuit of a more stable image forming method that is resistant to repeated use over a long period of time and environmental changes during use. For this purpose, it is necessary to comprehensively improve the durability of each element related to image formation by acting on the electrophotographic photosensitive member (sometimes simply referred to as a photosensitive member) and the peripheral photosensitive member.
[0005]
[Problems to be solved by the invention]
  The present invention has been made to meet the above requirements. That is, an object of the present invention is to provide a method for increasing the durability of the photosensitive member itself, the electrostatic latent image developing toner acting on the photosensitive member and the cleaning device during repeated use. More specifically, the toner for developing an electrostatic latent image eliminates image blur due to wear of the cleaning blade, toner slip on the surface of the photosensitive member during cleaning, or toner fixation, and eliminates fluctuations in image density due to the temperature and humidity environment during use. And manufacturing method thereof and image forming method using the sameThe lawIt is to provide.
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the inventors of the present invention have achieved the object of the present invention by adopting the following configuration.
[0007]
  [1] An electrostatic latent image developing toner obtained by forming toner particles in an aqueous medium, wherein the toner has a moisture content.0.2-2.1Mass%, free fatty acid content0.02-0.6A toner for developing an electrostatic latent image, which comprises, as an external additive, a fatty acid calcium salt in an amount of% by mass.
[0009]
  [2The fatty acid calcium salt is calcium stearate [1〕RecordToner for developing electrostatic latent image.
[0010]
  [3It is obtained by agglomerating and fusing at least resin particles in an aqueous medium [1]Or [2]The toner for developing an electrostatic latent image.
[0011]
  [4The toner contains, as an external additive, inorganic / organic composite fine particles in which inorganic fine particles having a primary average particle size of 5 to 100 nm are fixed on the surface of organic fine particles having an average particle size of 0.1 to 5.0 μm. [1]-[3The toner for developing an electrostatic latent image according to any one of the above.
[0012]
  [5The number average particle size of the toner is 3 to 8 μm, the variation coefficient of the shape factor is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less.4The toner for developing an electrostatic latent image according to any one of the above.
[0013]
  [6The number average particle diameter of the toner is 3 to 8 μm, and the proportion of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more. The toner for developing an electrostatic latent image according to any one of the above.
[0014]
  [7The number average particle diameter of the toner is 3 to 8 μm,The proportion of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more.The electrostatic latent image developing toner according to any one of [1] to [5], wherein the toner is an electrostatic latent image developing toner.
[0015]
  [8The electrostatic latent image according to any one of [1] to [5], wherein the number average particle diameter of the toner is 3 to 8 μm, and the proportion of toner particles without corners is 50 number% or more. Toner for image development.
[0016]
  [9When the particle diameter of the toner is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23 to represent the most frequent class in the histogram showing the number-based particle size distribution. The sum (M) of the relative frequency (m1) of the toner particles contained and the relative frequency (m2) of the toner particles contained in the next most frequent class is 70% or more. The toner for developing an electrostatic latent image according to any one of [1] to [5].
[0017]
  [10]CornerThe electrostatic latent image development according to any one of [1] to [5], wherein the ratio of the toner without toner is 50% by number or more and the number variation coefficient in the number particle size distribution is 27% or less. Toner.
[0018]
  [11The ratio of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape factor is 16% or less [1] To [5] The toner for developing an electrostatic latent image according to any one of [5].
[0019]
  [12The toner is obtained by salting out, aggregating and fusing the composite resin particles obtained by the multistage polymerization method and the colorant particles, and a release agent is provided in a region other than the outermost layer of the composite resin particles. [1] to [1] characterized in that the toner contained therein is used.11The toner for developing an electrostatic latent image according to any one of the above.
[0020]
  [13A toner resin having a peak or shoulder of gel permeation chromatography (GPC) at least 100,000 to 1,000,000 and 1,000 to 50,000 is used.12The toner for developing an electrostatic latent image according to any one of the above.
[0021]
  [14]GetThe use of a toner resin in which the peak or shoulder of the permeation chromatography (GPC) is at least 100,000 to 1,000,000, 25,000 to 100,000, and 1,000 to 25,000. The electrostatic latent image developing toner according to any one of [1] to [13].
[0022]
  [15[1] to [1] characterized in that it contains a resin, a release agent and a colorant, and has a crushing strength index of 0.1 to 0.8.14The toner for developing an electrostatic latent image according to any one of the above.
[0025]
  [16The electrostatic latent image formed on the organic photoconductor is developed with a developer containing toner, and the toner image visualized by the development is transferred from the organic photoconductor to a transfer material, and then on the organic photoconductor. An image forming method comprising a cleaning means for removing toner remaining on the toner, wherein the toner according to any one of [1] to [15] is used.
[0026]
  [17The organic photoreceptor has a structure in which a photosensitive layer is provided on a conductive support, and the surface layer of the photosensitive layer contains a polycarbonate having an average molecular weight of 40,000 or more [1.6] The image forming method described above.
[0027]
  [18At least toner particles are formed by forming particles in an aqueous medium, and after the particles are dried, 0.3 to 1.2% by mass of fatty acid calcium salt particles are externally added. A method for producing a toner for developing an electrostatic latent image, comprising producing a toner.
[0028]
The fatty acid calcium used in the present invention is specifically as follows.
[0029]
Calcium undecylate, calcium laurate, calcium tridecylate, calcium dodecylate, calcium myristate, calcium palmitate, calcium pentadecylate, calcium stearate, calcium behenate, calcium heptadelate, calcium aralate, calcium montanate, calcium oleate, Long chain fatty acid calcium such as calcium linoleate, calcium arachidinate, and behenate. The fatty acid component may be a single fatty acid or a mixed fatty acid, and among these, calcium stearate is particularly preferable. The external addition amount is preferably 0.005 to 0.3% by mass of the toner mass.
[0030]
As a production method, (1) a melting method in which a fatty acid and calcium oxide or calcium hydroxide are melt-reacted at a temperature higher than the melting point of the fatty acid calcium salt to be produced; (2) a slurry of fatty acid and calcium oxide or calcium hydroxide; Any of the semi-melting method in which the molten fatty acid calcium salt is melted below the melting point or (3) a metathesis method in which an aqueous solution of an inorganic metal salt is added to an aqueous solution of a fatty acid sodium salt and sodium is replaced with calcium may be used.
[0031]
In the case of fatty acid calcium, the preferable water content and free fatty acid content are almost as follows.
[0032]
The water content of the fatty acid calcium is preferably 0.1 to 2.5% by mass, and particularly preferably 0.3 to 1.2% by mass from the viewpoint of increasing the humidity stability of charging. The amount of free fatty acid is preferably from 0.01 to 0.7% by mass, particularly preferably from 0.05 to 0.5% by mass. If it exceeds 0.5% by mass, it may contaminate charging members such as carriers and developer carriers (developing roll surfaces). If it is less than 0.05% by mass, blade wear tends to increase. Yes, there is a possibility of shortening the life of the cleaning blade.
[0033]
In addition, about the measuring method of the moisture content contained in fatty-acid calcium, and the amount of free fatty acids, it carried out as follows.
[0034]
1) Measurement of water content
The moisture content is measured using the Karl Fischer method.
[0035]
As a specific measurement method, a method of measuring under the following conditions using a Hiranuma trace moisture meter (AQS-712: manufactured by Hiranuma Sangyo) can be mentioned.
[0036]
Sample heating temperature: 110 ° C
Sample heating time: 1 minute
Nitrogen gas flow rate: 150 ml / min
2) Measurement of free fatty acids
Weigh exactly 1 g of sample, dissolve in 1: 1 mixture of ethanol and ethyl ether, neutralize and titrate with aqueous potassium hydroxide using phenolphthalein as an indicator, and determine the content of free fatty acids by mass percentage of stearic acid. Expressed in
[0037]
In the present invention, inorganic / organic composite fine particles as abrasive particles are preferably used as an external additive of the toner. The inorganic / organic composite fine particles have a spherical shape, the surface is a hard inorganic fine powder, and the core uses organic elastic particles that are relatively elastic. Stable cleaning performance is exhibited without causing scratches on the photoreceptor or the cleaning blade.
[0038]
The primary average particle diameter of the inorganic fine particles constituting the inorganic / organic composite fine particles is preferably 5 to 100 nm from the viewpoint of improving cleaning properties, polishing properties, and filming resistance. The primary average particle diameter of the inorganic fine particles refers to a number-based average particle diameter measured by image analysis with a scanning electron microscope.
[0039]
Constituent materials of inorganic fine particles include silicon oxide, titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, cerium oxide, tungsten oxide, antimony oxide, copper oxide, tellurium oxide, manganese oxide, barium titanate, strontium titanate, titanium Magnesium acid, silicon nitride, carbon nitride and the like are used.
[0040]
The organic fine particles constituting the inorganic / organic composite fine particles are preferably resin particles made of an acrylic acid polymer, a styrene polymer, a styrene-acrylic acid copolymer, or the like.
[0041]
The acrylic polymer constituting the organic fine particles is a homopolymer or copolymer obtained by polymerizing a monomer selected from acrylic acid or acrylic ester, methacrylic acid or methacrylic ester. Examples of the acrylic acid monomer used to obtain the acrylic acid polymer include acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, and n-acrylate. Octyl, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, methacrylic acid Propyl, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethyl methacrylate Ruaminoechiru, and diethylaminoethyl methacrylate. An acrylic acid polymer can be obtained from one or more of the above acrylic monomers, but in the present invention, one or more other monomers are copolymerized as required. It may be a thing. In this case, it is preferable to use the acrylic monomer in the monomer composition at a ratio of 50% by mass or more.
[0042]
Examples of styrenic monomers used to obtain styrenic polymers constituting organic fine particles include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-ethyl. Styrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene , Pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, and the like. A styrene polymer can be obtained from one or more of the above styrene monomers. In the present invention, one or more other monomers are copolymerized as required. There may be. In this case, it is preferable to use a styrene monomer in the monomer composition in a proportion of 50% by mass or more.
[0043]
The styrene-acrylic acid copolymer constituting the organic fine particles can be obtained by using one or more of the acrylic monomers and one or more of the styrene monomers, but is necessary. Depending on the case, one or two or more other monomers may be copolymerized. In this case, in the monomer composition, the total of the acrylic acid monomer and the styrene monomer is preferably used at a ratio of 50% by mass or more.
[0044]
Examples of the other monomers include acrylic compounds such as acrylonitrile, methacrylonitrile and acrylamide, vinyl esters such as vinyl acetate, vinyl butyrate and vinyl benzoate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether, vinyl Examples thereof include vinyl ketones such as methyl ketone, dienes such as butadiene and isoprene, unsaturated carboxylic acids such as maleic acid and fumaric acid, and the like.
[0045]
The average particle size of the organic fine particles constituting the inorganic / organic composite fine particles is preferably from 0.1 to 5.0 μm, particularly preferably from 0.2 to 3.0 μm, from the viewpoint of improvement in cleaning properties and stability of triboelectric charging properties. . The average particle size of the organic fine particles is a volume-based average particle size measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser. . However, before the measurement, 10 mg of organic fine particles were dispersed in 50 ml of water together with a surfactant, and then pretreatment was performed with an ultrasonic homogenizer (output 150 W) for 1 to 10 minutes while paying attention to re-aggregation due to heat generation.
[0046]
The inorganic / organic composite fine particles are constituted by fixing inorganic fine particles treated with the specific treatment compound on the surface of the organic fine particles. Here, the term “fixation” refers to a state in which the inorganic fine particles are not simply attached to the organic fine particles by electrostatic force but the length of the portion embedded in the organic fine particles is 5 to 95%. Such a state can be confirmed by observing the surface of the inorganic / organic composite fine particles with a transmission electron microscope or a normal electron microscope. When fixing the inorganic fine particles to the surface of the organic fine particles, it is preferable to first spheroidize the organic fine particles and then fix the inorganic fine particles to the surface of the organic fine particles. This is because when the organic fine particles are spherical, the inorganic fine particles are fixed uniformly and the release of the inorganic fine particles is effectively prevented. Means for spheroidizing organic fine particles include a method in which organic fine particles are once melted by heat and then spray granulation, a method in which heat-melted organic fine particles are discharged into water to form a sphere, a suspension polymerization method or Examples include a method of synthesizing spherical organic fine particles by an emulsion polymerization method.
[0047]
As means for fixing inorganic fine particles to the surface of organic fine particles, there are a method of mixing organic fine particles and inorganic fine particles and then applying heat, a so-called mechanochemical method of mechanically fixing inorganic fine particles to the surface of organic fine particles, etc. Used. Specifically, organic fine particles and inorganic fine particles are mixed and mixed by stirring with a Henschel mixer, a V-type mixer, a turbuler mixer, etc., and the inorganic fine particles are adhered to the surface of the organic fine particles by electrostatic force, and then the surface is inorganic. A method in which organic fine particles with fine particles attached are introduced into a heat treatment device such as a nilo atomizer or a spray dryer, and the surface of the organic fine particles is softened by applying heat to fix the inorganic fine particles to the surface. After attaching the inorganic fine particles, the inorganic fine particles are fixed to the surface of the organic fine particles using a device capable of applying mechanical energy by modifying the impact pulverizer, such as an ang mill, a free mill, or a hybridizer. Or the like.
[0048]
In obtaining the inorganic / organic composite fine particles, the amount of the inorganic fine particles mixed with the organic fine particles may be an amount that can uniformly cover the surface of the organic fine particles. Specifically, although depending on the specific gravity of the inorganic fine particles, the inorganic fine particles are generally used in a proportion of 5 to 100% by mass, preferably 5 to 80% by mass with respect to the organic fine particles. If the proportion of the inorganic fine particles is too small, the cleaning property tends to be lowered. Conversely, if the proportion of the inorganic fine particles is too large, the inorganic fine particles are likely to be liberated.
[0049]
The above inorganic / organic composite fine particles are added to and mixed with the colored particles to constitute a toner. The blending ratio of the inorganic / organic composite fine particles is different from that of the colored particles from the viewpoint of improving the cleaning property and the stability of the triboelectric charging property. On the other hand, 0.01-5.0 mass% is preferable, and 0.01-2.0 mass% is particularly preferable.
[0050]
Examples of abrasives that are externally added as abrasives other than inorganic / organic composite fine particles include calcium titanate powder, barium titanate powder, magnesium titanate powder, strontium titanate powder, cerium oxide powder, zirconium oxide powder, and titanium oxide. There are powders, aluminum oxide powders, boron carbide powders, silicon carbide powders, silicon oxide powders, diamond powders, etc., which are used alone or in combination. Of these, strontium titanate powder and cerium oxide powder are particularly preferably used.
[0051]
The amount of the abrasive is preferably 0.1 to 10.0 parts by mass, more preferably 0.2 to 5.0 parts by mass with respect to 100 parts by mass of the toner particles.
[0052]
DETAILED DESCRIPTION OF THE INVENTION
The members and compounds that constitute the requirements of the present invention will be further described.
[0053]
The cleaning device used in the present invention is of a cleaning blade type.
[0054]
The cleaning blade used in the present invention is preferably an elastic rubber blade, and its physical properties can control the torque fluctuation of the present invention by controlling the rubber hardness and the rebound resilience at the same time, and the reversal of the blade can be more effectively suppressed. When the JISA hardness of the blade at 25 ± 5 ° C. is smaller than 65, the blade is easily reversed, and when it is larger than 80, the cleaning performance is deteriorated. Further, when the resilience exceeds 80, the blade is easily reversed, and when it is 20 or less, the cleaning performance is deteriorated. More preferable impact resilience is 20 or more and 80 or less. Young's modulus is 294-588 N / cm²The thing of the range of is preferable. The JISA hardness and impact resilience in the present invention are measured based on the vulcanized rubber physical test method of JISK6301. The value of rebound resilience indicates%.
[0055]
As the material of the elastic rubber blade used for the cleaning blade, urethane rubber, silicone rubber, fluorine rubber, chloropyrene rubber, butadiene rubber, and the like are known. Of these, urethane rubber is compared with other rubbers. It is particularly preferable because of its excellent wear characteristics. For example, urethane rubber obtained by reaction-curing polycaprolactone ester and polyisocyanate described in JP-A-59-30574 is particularly preferable.
[0056]
In the present invention, it is preferable that the elastic rubber blade is fixed to the support member substantially by the support member on the photoreceptor contact surface side. By adopting such a holding method, the torque fluctuation of the cleaning blade can be stabilized.
[0057]
The proper pressure contact condition of the elastic rubber blade to the surface of the photoreceptor is determined by a delicate balance of various characteristics and is quite narrow. The setting varies depending on characteristics such as the thickness of the elastic rubber blade, and requires precision. However, since elastic rubber blades can vary slightly in their thickness at the time of production, they cannot always be set under the proper conditions. May be out of the proper area. In particular, when combined with an organic photosensitive layer using a high molecular weight binder resin, image defects such as filming and black spots are likely to occur when the film deviates from an appropriate region.
[0058]
Therefore, it is necessary to take measures to cancel the variation in the characteristics of the elastic rubber blade. Even if the thickness of the elastic rubber blade is different, the pressure contact force on the surface of the photoreceptor is not affected. Would be effective.
[0059]
In the present invention, it is preferable that the free end of the elastic rubber blade is pressed in a direction opposite to the rotation direction of the photoreceptor (counter direction).
[0060]
If necessary, the cleaning blade can be sprayed with a fluorine-based lubricant on the edge of the cleaning blade, or on the tip of the cleaning blade over the entire width direction, the following fluorine-based polymer and fluorine-based resin powder. It is preferable to apply a dispersion in which is dispersed in a fluorine-based solvent.
[0061]
Next, the organic photoreceptor used in the present invention will be described.
In the present invention, an organic electrophotographic photoreceptor (organic photoreceptor) is an electrophotographic structure in which an organic compound has at least one of a charge generation function and a charge transport function essential to the construction of an electrophotographic photoreceptor. It means a photoreceptor, and all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function, etc. contains.
[0062]
The constitution of the organic photoreceptor used in the present invention is described below.
The conductive support used in the photoreceptor of the present invention may be either a sheet or a cylinder, but a cylindrical conductive support is more preferable for designing an image forming apparatus in a compact manner.
[0063]
The cylindrical conductive support used in the present invention means a cylindrical support necessary to be able to form an endless image by rotating, and has a straightness of 0.1 mm or less and a deflection of 0.1 mm or less. A conductive support in the above is preferred. Exceeding the roundness and shake range makes it difficult to form a good image.
[0064]
As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper or plastic drum coated with a conductive substance can be used. As a conductive support, the specific resistance is 10 at room temperature.^ThreeΩ · cm or less is preferable.
[0065]
As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing treatment in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / liter, the aluminum ion concentration is 1 to 10 g / liter, the liquid temperature is preferably around 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.
[0066]
In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.
[0067]
In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the support and the photosensitive layer. Including) can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more repeating units of these resins. Of these resins, a polyamide resin is preferable as a resin capable of reducing an increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.
[0068]
The intermediate layer most preferably used in the present invention includes an intermediate layer using a curable metal resin obtained by thermally curing an organic metal compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.
[0069]
The photosensitive layer configuration of the photoreceptor of the present invention may be a single layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer. It is preferable that the generation layer (CGL) and the charge transport layer (CTL) be separated. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.
[0070]
The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.
The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.
[0071]
A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, the CGM that can minimize the increase in residual potential due to repeated use has a three-dimensional and potential structure that can form a stable aggregate structure among a plurality of molecules. Specifically, a phthalocyanine having a specific crystal structure. CGM of pigments and perylene pigments. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have little deterioration due to repeated use. Potential increase can be reduced.
[0072]
When a binder is used as a CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.
[0073]
The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. Other substances may contain additives such as antioxidants as necessary.
[0074]
A known charge transport material can be used as the charge transport material (CTM). For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM capable of minimizing the increase in residual potential due to repeated use has a high mobility and an ionization potential difference from the combined CGM of 0.5 (eV) or less, preferably 0 .25 (eV) or less.
[0075]
The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).
[0076]
Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resins, silicone resins, melamine resins, and copolymer resins containing two or more of the repeating units of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.
[0077]
The most preferable binder for these CTLs is a polycarbonate resin having an average molecular weight of 40,000 or more. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably 10 to 40 μm.
[0078]
Various resin layers can be provided as a protective layer of the photoreceptor used in the present invention. In particular, by providing a cross-linked resin layer, the organic photoreceptor of the present invention having high mechanical strength can be obtained.
[0079]
Among the layers constituting the photoreceptor, it is preferable to use a polycarbonate having an average molecular weight of 40,000 or more as a binder resin for the outermost layer in order to improve durability.
[0080]
Examples of the solvent or dispersion medium used for forming the intermediate layer, photosensitive layer, protective layer and the like of the present invention include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, Acetone, methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene , Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.
[0081]
Next, as a coating processing method for producing the organic electrophotographic photoreceptor of the present invention, a coating processing method such as dip coating, spray coating, circular amount regulation type coating or the like is used. In order to prevent the lower layer film from being dissolved as much as possible, it is preferable to use a coating method such as spray coating or circular amount regulation type (circular slide hopper type is a typical example) coating in order to achieve uniform coating processing. It is most preferable that the protective layer of the present invention uses the circular amount regulation type coating method. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.
[0082]
Next, the toner used in the present invention will be described.
The toner of the present invention is a toner for developing an electrostatic latent image obtained by forming toner particles in an aqueous medium. This means that dispersed particles are formed in an aqueous medium and used as toner particles. Included are those produced by agglomerating and fusing several particles rather than the particles as they are.
[0083]
Preparation of fine resin particles by suspension polymerization in aqueous medium or emulsion polymerization or miniemulsion polymerization of monomer in aqueous medium, followed by addition of organic solvent, salt and other flocculants Thus, the resin particles can be produced by a method of aggregating and fusing. In addition, a step of preparing an oil component by dissolving or dispersing the binder resin, a charge control agent, a colorant, and a release agent in an organic solvent in which the binder resin is soluble, and the oil component is dispersed in an aqueous medium. It can also be produced by a method for producing a toner for developing an electrostatic latent image having a step of granulating toner from the state. Above all, monomers are emulsion-polymerized or miniemulsion-polymerized in an aqueous medium to prepare fine resin particles. After that, an aggregating agent such as an organic solvent or salts is added to agglomerate and melt the resin particles. It is particularly preferable that the toner is manufactured by the method because the toner shape control is relatively easy and stable cleaning properties can be obtained.
[0084]
An example of the method for producing the toner of the present invention by the suspension polymerization method is to dissolve the charge control resin in the polymerizable monomer, and to add a colorant, a release agent if necessary, a polymerization initiator, etc. These constituent materials are added, and the constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets of a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Then, it transfers to the reaction apparatus (stirring apparatus) which has a 2 step | paragraph stirring blade, and a polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention. In the present invention, the “aqueous medium” refers to a medium containing at least 50% by mass of water.
[0085]
In the case of the emulsion polymerization method, a method of preparing the toner of the present invention by salting out, aggregating and fusing resin particles in an aqueous medium is preferably used. Can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, or a constituent material such as resin particles and a colorant, and in particular using an emulsifier in water Then, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer is heated and fused at a temperature higher than the glass transition temperature of the polymer itself to gradually grow the particle size while forming fused particles. When the desired particle size is reached, a large amount of water is added to stop the particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluid state while containing water. By drying, the toner of the present invention can be formed. Here, a solvent that is infinitely soluble in water, such as alcohol, may be added simultaneously with the flocculant.
[0086]
For the toner in the present invention, composite resin particles obtained by a multistage polymerization method can also be used. It is preferable that a release agent is contained in a region other than the outermost layer of the composite resin particle.
[0087]
The manufacturing process of the multistage polymerization toner is mainly composed of the following processes. 1: Multistage polymerization step (I) for obtaining composite resin particles in which a release agent is contained in a region other than the outermost layer (central portion or intermediate layer)
2: Salting out / fusion process for obtaining toner particles by salting out / fusion of composite resin particles and colorant particles (II)
3: Filtration / washing step of separating the toner particles from the toner particle dispersion and removing the surfactant from the toner particles.
4: a drying process for drying the washed toner particles;
5: Step of adding an external additive to the dried toner particles
Consists of
[0088]
Hereinafter, each step will be described in detail.
Multistage polymerization process (I)
The multistage polymerization step (I) is a step of producing composite resin particles by a multistage polymerization method in which a coating layer made of a monomer polymer is formed on the surface of the resin particles.
[0089]
In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoint of production stability and crushing strength of the resulting toner.
[0090]
Hereinafter, the two-stage polymerization method and the three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described.
[0091]
Two-stage polymerization method
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin containing a release agent and an outer layer (shell) formed from a low molecular weight resin. is there.
[0092]
This method will be described in detail. First, a release agent is dissolved in a monomer to prepare a monomer solution, and the monomer solution is added to an oil droplet in an aqueous medium (for example, a surfactant aqueous solution). After the dispersion, the system is polymerized (first stage polymerization) to prepare a dispersion of high molecular weight resin particles containing a release agent.
[0093]
Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the dispersion of the resin particles, and the monomer is polymerized in the presence of the resin particles (second stage polymerization). Thus, a coating layer made of a low molecular weight resin (a monomer polymer used later) is formed on the surface of the resin particles.
[0094]
Three-stage polymerization method
The three-stage polymerization method produces composite resin particles composed of a central part (core) formed from a high molecular weight resin, an intermediate layer containing a release agent, and an outer layer (shell) formed from a low molecular weight resin. Is the method.
[0095]
This method will be specifically described. First, a dispersion of resin particles obtained by a polymerization process (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). In the aqueous medium, a monomer solution obtained by dissolving a release agent in a monomer is dispersed in oil droplets, and then this system is polymerized (second-stage polymerization) to obtain resin particles (cores). A coating layer (intermediate layer) made of a resin containing a release agent (monomer polymer used in the second stage) is formed on the surface of the particles, and composite resin particles (high molecular weight resin-intermediate molecular weight) are formed. (Resin) is prepared.
[0096]
Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the obtained dispersion of composite resin particles, and the monomer is polymerized in the presence of the composite resin particles (third-stage polymerization). ) To form a coating layer made of a low molecular weight resin (the monomer polymer used last) on the surface of the composite resin particles. In the above method, the incorporation of the second stage polymerization is preferable because the release agent can be finely and uniformly dispersed.
[0097]
One feature of the toner production method according to the present invention is that the polymerizable monomer is polymerized in an aqueous medium. That is, when forming resin particles (core particles) or coating layer (intermediate layer) containing a release agent, the release agent is dissolved in the monomer, and the resulting monomer solution is oiled in an aqueous medium. It is a method of obtaining latex particles by dispersing in drops and adding a polymerization initiator to this system for polymerization treatment.
[0098]
The aqueous medium as used in the field of this invention means the medium which consists of 50-100 mass% of water and 0-50 mass% of water-soluble organic solvents. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, and an alcohol-based organic solvent that does not dissolve the obtained resin is preferable.
[0099]
As a suitable polymerization method for forming resin particles (core particles) containing a release agent or a coating layer thereof, a release agent is dissolved in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. A monomer solution in which the agent is dissolved in a monomer is dispersed in oil droplets using mechanical energy to prepare a dispersion, and a water-soluble polymerization initiator is added to the resulting dispersion to obtain oil droplets. Among them, a method of radical polymerization (hereinafter referred to as “mini-emulsion method” in the present invention) can be given, and the effects of the present invention can be further exhibited, which is preferable. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.
[0100]
According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, the release agent dissolved in the oil phase is not detached and the resin particles (core particles) are formed. Alternatively, a sufficient amount of a release agent can be introduced into the coating layer.
[0101]
Here, the dispersing machine for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirring device “CLEARMIX” (M-Technique Co., Ltd.) equipped with a rotor that rotates at high speed. Product), ultrasonic dispersers, mechanical homogenizers, Manton gorin, pressure homogenizers, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 50 to 1000 nm, and more preferably 30 to 300 nm.
[0102]
In addition, as another polymerization method for forming the resin particles or the coating layer containing the release agent, a known method such as an emulsion polymerization method, a suspension polymerization method, or a seed polymerization method may be employed. These polymerization methods can also be employed to obtain resin particles (core particles) constituting the composite resin particles or coating layers thereof that do not contain a release agent.
[0103]
The particle diameter of the composite resin particles obtained in the polymerization step (I) is in the range of 10 to 1000 nm as a weight average particle diameter measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). It is preferable that it exists in.
[0104]
Moreover, it is preferable that the glass transition temperature (Tg) of a composite resin particle exists in the range of 48-74 degreeC, More preferably, it is 52-64 degreeC.
[0105]
The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C.
Salting out / fusion process (II)
In the salting out / fusion step (II), the composite resin particles and the colorant particles obtained in the multistage polymerization step (I) are salted out / fused (salting out and fusion occur simultaneously). This is a step of obtaining irregular (non-spherical) toner particles.
[0106]
In the present invention, salting out / fusion means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur simultaneously, or act of causing salting out and fusion at the same time. . In order to perform salting-out and fusion at the same time, it is necessary to agglomerate particles (composite resin particles, colorant particles) under a temperature condition higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .
[0107]
In the salting-out / fusion step (II), internal additive particles such as charge control agents (fine particles having a number average primary particle size of about 10 to 1000 nm) are salted out / fused together with the composite resin particles and the colorant particles. You may let them. The colorant particles may be surface-modified, and conventionally known ones can be used as the surface modifier.
[0108]
The colorant particles are subjected to a salting out / fusion process in a state of being dispersed in an aqueous medium. The aqueous medium in which the colorant particles are dispersed is preferably an aqueous solution in which the surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC).
[0109]
The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but preferably, a stirrer “CLEARMIX” (manufactured by M-Technique) equipped with a rotor that rotates at high speed, an ultrasonic disperser, Examples thereof include a pressure disperser such as a mechanical homogenizer, a manton gourin, and a pressure homogenizer, and a medium disperser such as a Getzman mill and a diamond fine mill.
[0110]
In order to salt out / fuse the composite resin particles and the colorant particles, a salting-out agent (flocculating agent) having a critical aggregation concentration or more is added to the dispersion in which the composite resin particles and the colorant particles are dispersed. In addition, it is necessary to heat the dispersion to a temperature higher than the glass transition temperature (Tg) of the composite resin particles.
[0111]
The temperature range suitable for salting out / fusion is (Tg + 10 ° C.) to (Tg + 50 ° C.), particularly preferably (Tg + 15 ° C.) to (Tg + 40 ° C.). In addition, an organic solvent that is infinitely soluble in water may be added in order to effectively perform fusion.
[0112]
Filtration and washing process
In this filtration / washing step, a filtration treatment for filtering the toner particles from the toner particle dispersion obtained in the above step, and a surfactant or salt from the filtered toner particles (cake-like aggregate). A cleaning process for removing deposits such as a depositing agent is performed.
[0113]
Here, the filtration method is not particularly limited, such as a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press or the like.
[0114]
Drying process
This step is a step of drying the washed toner particles.
[0115]
Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers It is preferable to use a stirring dryer or the like.
[0116]
The water content of the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.
[0117]
In addition, when the toner particles that have been dried are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
[0118]
The toner particles (colored particles) of the present invention can be prepared by salting out / fusing, but there is no particular limitation, but the composite resin particles are formed in the absence of the colorant and the composite resin particle dispersion is formed. It is preferable to prepare by adding a dispersion of colorant particles and salting out / fusion-bonding the composite resin particles and the colorant particles.
[0119]
Thus, by performing the preparation of the composite resin particles in a system in which no colorant is present, the polymerization reaction for obtaining the composite resin particles is not inhibited. Therefore, according to the toner of the present invention, the excellent offset resistance is not impaired, and the fixing device is not contaminated or the image is not stained due to the accumulation of toner.
[0120]
In addition, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the obtained toner particles, and the heat fixing step of the image forming method using the toner In this case, no off-flavor is generated.
[0121]
Furthermore, since the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, an image with excellent sharpness can be formed over a long period of time. According to such a toner having a uniform composition, molecular weight, and surface characteristics between toner particles, an image forming method including a fixing process using a contact heating method maintains good adhesion (high fixing strength) to an image support. However, it is possible to improve the anti-offset property and the anti-winding property, and an image having an appropriate gloss can be obtained.
[0122]
Next, each constituent material and element used in the toner manufacturing process will be described in detail.
[0123]
(Polymerizable monomer)
As a polymerizable monomer for producing the resin (binder) used in the present invention, a hydrophobic monomer is an essential constituent, and a crosslinkable monomer is used as necessary. Moreover, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group as described below.
[0124]
(1) Hydrophobic monomer
The hydrophobic monomer constituting the monomer component is not particularly limited, and conventionally known monomers can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.
[0125]
Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.
[0126]
Examples of the vinyl aromatic monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p- n-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4 -Styrene monomers such as dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
[0127]
Examples of acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like.
[0128]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
[0129]
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.
[0130]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.
[0131]
Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.
[0132]
(2) Crosslinkable monomer
In order to improve the characteristics of the resin particles, a crosslinkable monomer may be added. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.
[0133]
(3) Monomers having acidic polar groups
Examples of the monomer having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone group (—SOOH)._ThreeMention may be made of α, β-ethylenically unsaturated compounds having H).
[0134]
Examples of the α, β-ethylenically unsaturated compound (a) having a —COOH group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid. Examples thereof include acid monooctyl esters, and metal salts thereof such as Na and Zn.
[0135]
-SO of (b)_ThreeExamples of the α, β-ethylenically unsaturated compound having an H group include sulfonated styrene, its Na salt, allylsulfosuccinic acid, octyl allylsulfosuccinate, and its Na salt.
[0136]
(4) Monomers having basic polar groups
As the monomer having a basic polar group, (i) a (meth) acrylic acid having 1 to 12 carbon atoms, preferably 2 to 8 and particularly preferably 2 aliphatic alcohols having an amine group or a quaternary ammonium group. Acid esters, (ii) (meth) acrylic acid amides or optionally (meth) acrylic acid amides mono- or di-substituted with alkyl groups of 1 to 18 carbon atoms on N, (iii) heterocycles having N as a ring member Examples thereof include vinyl compounds substituted with a ring group and (iv) N, N-diallyl-alkylamine or a quaternary ammonium salt thereof. Among them, (i) aliphatic alcohol (meth) acrylic acid ester having an amine group or quaternary ammonium group is preferable as a monomer having a basic polar group.
[0137]
Examples of (meth) acrylic acid esters of aliphatic alcohols having an amine group or quaternary ammonium group (i) include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the above four compounds. A quaternary ammonium salt, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, etc. can be mentioned.
[0138]
(Ii) (Meth) acrylic acid amide or optionally mono- or dialkyl-substituted (meth) acrylic acid amide on N includes acrylamide, N-butylacrylamide, N, N-dibutylacrylamide, piperidylacrylamide, methacrylamide, N-butylmethacrylamide, N, N-dimethylacrylamide, N-octadecylacrylamide and the like can be mentioned.
[0139]
Examples of the vinyl compound substituted with a heterocyclic group having N as a ring member in (iii) include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like.
[0140]
Examples of (iv) N, N-diallyl-alkylamine include N, N-diallylmethylammonium chloride and N, N-diallylethylammonium chloride.
[0141]
(Polymerization initiator)
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (for example, potassium persulfate, ammonium persulfate, etc.), azo compounds (for example, 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) Salt), peroxide compounds and the like. Furthermore, the radical polymerization initiator can be combined with a reducing agent as necessary to form a redox initiator. Use of a redox initiator is preferred because the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be shortened.
[0142]
The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, it is possible to perform polymerization at room temperature or higher by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide and a reducing agent (ascorbic acid or the like).
[0143]
(Chain transfer agent)
A known chain transfer agent can be used for the purpose of adjusting the molecular weight. Although it does not specifically limit as a chain transfer agent, For example, the compound which has mercapto groups, such as an octyl mercaptan, a dodecyl mercaptan, a tert- dodecyl mercaptan, is used. In particular, a compound having a mercapto group is preferably used because it suppresses odor during heat-fixing, and a toner having a sharp molecular weight distribution is obtained, and is excellent in storage stability, fixing strength, and offset resistance. For example, ethyl thioglycolate, propyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate , A compound having a mercapto group of ethylene glycol, a compound having a mercapto group of neopentyl glycol, and a compound having a mercapto group of pentaerythritol. Among these, n-octyl-3-mercaptopropionic acid ester is particularly preferable from the viewpoint of suppressing odor during toner heat fixing.
[0144]
(Surfactant)
In particular, in order to perform miniemulsion polymerization using the above-described polymerizable monomer, it is preferable to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used in this case is not particularly limited, and the following ionic surfactants can be given as examples of suitable compounds.
[0145]
Examples of the ionic surfactant include sulfonate (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol- 6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate sodium, etc.) , Sulfate salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, stearyl Potassium, calcium oleate and the like).
[0146]
Nonionic surfactants can also be used. Specifically, for example, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, Examples include sorbitan esters.
[0147]
In the present invention, these surfactants are mainly used as an emulsifier during emulsion polymerization, but may be used for other steps or for other purposes.
[0148]
(Molecular weight distribution of resin particles and toner)
The toner of the present invention preferably has a peak or shoulder at 100,000 to 1,000,000 and 1,000 to 50,000, and further has a peak or shoulder of 100,000 to 1,000,000, More preferably, it is present at 25,000 to 150,000 and 1,000 to 50,000.
[0149]
The molecular weight of the resin particles is both a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 50,000. A resin containing at least is preferable. More preferably, an intermediate molecular weight resin having a peak or shoulder at a peak molecular weight of 15,000 to 100,000 is preferably used.
[0150]
The molecular weight measurement method of the toner or resin is preferably measured by GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a solvent. That is, 1.0 ml of THF is added to 0.5 to 5 mg of a measurement sample, more specifically 1 mg, and the mixture is sufficiently dissolved by stirring at room temperature using a magnetic stirrer or the like. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., flowing THF at a flow rate of 1.0 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. The column is preferably used in combination with a commercially available polystyrene gel column. For example, Shodex KF-801, 802, 803, 804, 805, 806, 807 made by Showa Denko KK, TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be mentioned. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.
[0151]
(Flocculant)
The flocculant used in the present invention is preferably selected from metal salts.
[0152]
Examples of the metal salt include monovalent metals such as alkali metal salts such as sodium, potassium and lithium, divalent metals such as alkaline earth metal salts such as calcium and magnesium, and divalent metals such as manganese and copper. Examples thereof include trivalent metal salts such as salts, iron and aluminum.
[0153]
Specific examples of these metal salts are shown below. Specific examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride, and divalent metal salts such as calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose. In general, the divalent metal salt has a smaller critical aggregation concentration (coagulation value or coagulation point) than the monovalent metal salt, and the trivalent metal salt has a smaller critical aggregation concentration.
[0154]
The critical flocculation concentration referred to in the present invention is an index related to the stability of the dispersion in the aqueous dispersion, and indicates the concentration at which flocculation occurs when a flocculant is added. This critical coagulation concentration varies greatly depending on the latex itself and the dispersant. For example, it is described in Seizo Okamura et al., Polymer Chemistry 17,601 (1960), etc., and the value can be known by following these descriptions. As another method, a desired salt is added to the target particle dispersion at a different concentration, the ζ potential of the dispersion is measured, and the salt concentration at the point where the ζ potential begins to change is defined as the critical aggregation concentration. It is also possible to do.
[0155]
In the present invention, the polymer fine particle dispersion is treated with a metal salt so as to have a concentration equal to or higher than the critical aggregation concentration. At this time, as a matter of course, whether the metal salt is added directly or as an aqueous solution is arbitrarily selected according to the purpose. When added as an aqueous solution, the added metal salt must be equal to or higher than the critical aggregation concentration of the polymer particles with respect to the volume of the polymer particle dispersion and the total volume of the metal salt aqueous solution.
[0156]
The concentration of the metal salt as a flocculant in the present invention may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.
[0157]
Next, the step of forming the oil phase component by dissolving or dispersing each of the raw materials of the binder resin, the colorant, and the wax in an organic solvent, and the method of granulating the oil phase component in an aqueous medium are preferred in the present invention. An example of a manufacturing method is shown.
[0158]
From the state in which the oil component is prepared by dissolving or dispersing the binder resin, the charge control agent, the colorant, and the release agent in an organic solvent that dissolves the binder resin, and the oil component is dispersed in the aqueous medium. And a method for producing a toner for developing an electrostatic latent image.
[0159]
The step of preparing an oil component by dissolving and dispersing a binder resin, a colorant, and a wax in an organic solvent for solubilizing the binder resin is a binder resin, a charge control resin, a colorant, and a release agent. It is a step of mixing and dispersing in an organic solvent that solubilizes the resin.
[0160]
A general organic solvent is used as the organic solvent for solubilizing the binder resin. For example, hydrocarbons such as toluene, xylene and hexane, halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane, alcohols such as methanol and ethanol, ethers such as tetrahydrofuran, esters such as methyl acetate, ethyl acetate and butyl acetate And ketones such as acetone, methyl ethyl ketone, and cyclohexanone. Of these, ethyl acetate, methyl ethyl ketone, and the like are preferable from the viewpoint of the solubility and solvent-removability of the resin. These may be used alone or in combination.
[0161]
The step of granulating toner from a state in which an oily component is dispersed in an aqueous medium refers to solidifying the oily component prepared in the above step from the state of being dispersed in an aqueous medium to produce particles, which are then dried. In this step, the toner is obtained.
[0162]
As a particle production method, a solution obtained by dissolving and dispersing the binder resin, the charge control agent, the colorant, the release agent, and other materials in a solvent is suspended and dispersed in an aqueous medium, and then the solvent A method of removing particles, a method of precipitating particles by adding an aqueous poor solvent to the solution, and melting a heated melt containing a binder resin, a charge control agent, a colorant, a release agent, and other materials in an aqueous medium. Examples of the method include dispersing and then cooling to form particles.
[0163]
As the aqueous medium, water is mainly used, but a water-soluble solvent may be mixed. Furthermore, it is preferable in terms of particle size distribution to add a dispersant. Dispersants include tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, silica, cellulose, hydroxypropylmethylcellulose, methylcellulose, carboxymethylcellulose, starch, polyvinyl alcohol, polyacrylic An acid etc. are mentioned. The amount of the dispersant is preferably 0 to 20 parts by mass with respect to 100 parts by mass of the mother liquor.
[0164]
As a stirring method for producing particles, it is desirable to apply shear, and a homogenizer, a colloid mill, a dissolver, or the like is used.
[0165]
As the drying, aeration drying apparatus, spray drying apparatus, rotary drying apparatus, air flow drying apparatus, fluidized bed drying apparatus, heat transfer heating type drying apparatus, freeze drying apparatus and the like are known, and any of them can be used.
[0166]
Examples of the colorant constituting the toner of the present invention include various inorganic pigments, organic pigments, and dyes. A conventionally well-known thing can be used as an inorganic pigment. Specific inorganic pigments are exemplified below.
[0167]
Examples of the black pigment include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.
[0168]
These inorganic pigments can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0169]
When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 60% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.
[0170]
Conventionally known organic pigments and dyes can also be used. Specific organic pigments and dyes are exemplified below.
[0171]
Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.
[0172]
Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.
[0173]
Examples of green or cyan pigments include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.
[0174]
Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used.
[0175]
These organic pigments and dyes can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0176]
The colorant (colorant particles) constituting the toner of the present invention may be surface-modified. A conventionally well-known thing can be used as a surface modifier, Specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent etc. can be used preferably. Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyltrimethyl. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureido Examples thereof include propyltriethoxysilane. Examples of titanium coupling agents include TTS, 9S, 38S, 41B, 46B, 55, 138S, and 238S, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co., Inc. -1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA -30, TSDMA, TTAB, TTOP and the like. Examples of the aluminum coupling agent include “Plenact AL-M” manufactured by Ajinomoto Co., Inc.
[0177]
The addition amount of these surface modifiers is preferably 0.01 to 20% by mass, and more preferably 0.1 to 5% by mass with respect to the colorant.
[0178]
Examples of the method for modifying the surface of the colorant particles include a method in which a surface modifier is added to the dispersion of the colorant particles and this system is heated to react.
[0179]
The surface-modified colorant particles are collected by filtration, washed with the same solvent and filtered, and then dried.
[0180]
The toner used in the present invention is preferably a toner obtained by fusing resin particles encapsulating a release agent in an aqueous medium. In this way, the resin particles in which the release agent is encapsulated in the resin particles are salted out / fused in the aqueous medium with the colorant particles, whereby a toner in which the release agent is finely dispersed can be obtained.
[0181]
In the toner of the present invention, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene, and the like are preferable as the release agent, and ester compounds represented by the following formula are particularly preferable.
[0182]
R₁-(OCO-R₂)_n
In the formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, particularly preferably 4. R₁, R₂Each represents a hydrocarbon group which may have a substituent. R₁Has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 5 carbon atoms. R₂Has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.
[0183]
Next, the example of a typical compound is shown below.
[0184]
[Chemical 1]

[0185]
[Chemical 2]

[0186]
The amount of the compound added is 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass with respect to the whole toner.
[0187]
In the present invention, the “crushing strength index” is an index indicating the ease of crushing of toner particles, and specifically refers to an index obtained by the following method.
[0188]
(Method)
30 g of toner (sample) and 100 g of glass beads “GB503M” (manufactured by Toshiba Barotini Co., Ltd., particle size: 2 mm) are placed in a 2 liter polyethylene pot, mixed and stirred for 60 seconds with a turbuler mixer, and then a 330 mesh test sieve. Separate and remove the glass beads.
[0189]
Then, before and after mixing and stirring, the number ratio (%) of small particles of 2 to 4 μm in all toner particles is measured, and calculated by the following formula.
[0190]
Crushing strength index = (N−N₀) / 60
(In the formula, N is the number% of small particles of 2 to 4 μm after mixing and stirring, and N₀Is the number% of small particles of 2 to 4 μm before mixing and stirring. )
The “number% of small particles” is a value measured using a Coulter Multisizer. Specifically, a Coulter Multisizer is used, and an interface (manufactured by Nikkaki Co., Ltd.) that outputs a particle size distribution is connected to a personal computer. The aperture in the Coulter Multisizer was 100 μm, and the volume distribution of toner of 2 μm or more (for example, 2 to 40 μm) was measured and calculated.
[0191]
The toner of the present invention according to claim 16 is a toner containing a resin, a release agent, and a colorant, and is characterized in that a crushing strength index according to the above definition is 0.1 to 0.8.
[0192]
A toner having a crushing strength index exceeding 0.8 cannot have sufficient crushing resistance. When such a toner is used for image formation over a long period of time, filming, fogging, and carrier are caused by fine powder generated by crushing. Spent etc. occur.
[0193]
On the other hand, a toner having a crushing strength index of less than 0.1 tends to have a high minimum fixing temperature, and cannot sufficiently meet demands for miniaturization and low power consumption of a copying machine.
[0194]
The toner of the present invention is preferably prepared by encapsulating the release agent in resin particles by a mini-emulsion polymerization method, and salting out and fusing together with colored particles.
[0195]
To the toner of the present invention, so-called external additives can be added and used for the purpose of improving fluidity and improving cleaning properties. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.
[0196]
Examples of inorganic fine particles that can be used as an external additive include conventionally known fine particles. Specifically, silica fine particles, titanium fine particles, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic.
[0197]
Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150, H-200 manufactured by Hoechst. And commercially available products TS-720, TS-530, TS-610, H-5, and MS-5 manufactured by Cabot Corporation.
[0198]
Specific examples of the titanium fine particles include, for example, commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercial products MT-100S, MT-100B, MT-500BS, MT-600, and MT-600SS manufactured by Teika. , JA-1, commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB manufactured by Idemitsu Kosan Co., Ltd. IT-OC and the like.
[0199]
Specific examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.
[0200]
Examples of the organic fine particles that can be used as the external additive include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymer.
[0201]
The addition amount of the external additive is preferably about 0.1 to 5% by mass with respect to the toner.
[0202]
Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.
[0203]
The particle diameter of the toner of the present invention is preferably 2 to 10 [mu] m, more preferably 3 to 8 [mu] m in terms of number average particle diameter. This particle size can be controlled by the concentration of the flocculant (salting-out agent), the amount of organic solvent added, the fusing time, and the polymer composition in the toner production method.
[0204]
When the number average particle diameter is 2 to 10 μm, toner particles having high adhesion force that fly and adhere to the heating member and generate offset in the fixing process are reduced, and transfer efficiency is increased and halftone The image quality is improved, and the image quality of fine lines and dots is improved.
[0205]
The number average particle size of the toner can be measured using a Coulter Counter TA-II, Coulter Multisizer, SLAD 1100 (manufactured by Shimadzu Corporation: laser diffraction particle size measuring device) or the like.
[0206]
In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikka Machine Co., Ltd.) that outputs a particle size distribution and a personal computer are connected. The aperture in the Coulter Multisizer was 100 μm, and the volume distribution of toner of 2 μm or more (for example, 2 to 40 μm) was measured to calculate the particle size distribution and average particle size.
[0207]
The shape factor of the toner of the present invention is represented by the following formula and indicates the degree of roundness of the toner particles.
[0208]
Shape factor = ((maximum diameter / 2)²× π) / projection area
Here, the maximum diameter refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines. The projected area refers to the area of the projected image of the toner particles on the plane. In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.
[0209]
The ratio of toner particles having a shape factor in the range of 1.0 to 1.6 is desirably 65% by number or more.
[0210]
As the toner of the present invention, when the particle size of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the number-based particle size distribution is divided into a plurality of classes at intervals of 0.23. In the histogram shown, the sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the next most frequent class after the most frequent class is 70. % Of the toner is preferable.
[0211]
When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, selective development can be performed by using the toner in the image forming process. Can be reliably suppressed.
[0212]
In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.
[0213]
Measurement condition
1: Aperture: 100 μm
2: Sample preparation method: Electrolyte [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and 10-20 mg of a measurement sample was added thereto. Add. This system is prepared by dispersing for 1 minute with an ultrasonic disperser.
[0214]
For toner particles, a toner composed of toner particles having a shape coefficient variation coefficient of 16% or less and a number variation coefficient in a number particle size distribution of 27% or less can be used to improve developability and fine line reproducibility. Excellent and stable cleaning properties can be formed over a long period of time.
[0215]
Furthermore, as a result of investigations by paying attention to the minute shape of each toner particle, the present inventors have changed the shape of the corner portion of the toner particle to become round inside the developing device, and this portion has a blade wear. It was found that it was generated. The reason for this is not clear, but it is estimated that stress is easily applied to the corner portion and promotes blade wear in this portion.
[0216]
In addition, when charge is applied to the toner particles by frictional charging, it is presumed that the charge tends to concentrate particularly at the corners, and the toner particles are likely to be non-uniformly charged.
[0217]
That is, the ratio of toner particles having no corners is preferably 50% by number or more. Furthermore, by using toner composed of toner particles whose number variation coefficient in the number particle size distribution is controlled to 27% or less, excellent image developability and fine line reproducibility can be formed over a long period of time. I found out that I can.
[0218]
Further, it has been found that even when the toner is made to have a specific shape, the blade wear is reduced and the charge amount distribution becomes sharp.
[0219]
That is, the developing property can also be achieved by using a toner having a ratio of toner particles having a shape factor in the range of 1.2 to 1.6 of 65% by number or more and a variation coefficient of the shape factor of 16% or less. It is excellent in fine line reproducibility and can form a high-quality image over a long period of time.
[0220]
The variation coefficient of the shape factor of the toner of the present invention is calculated from the following equation.
Coefficient of variation (%) = (S / K) × 100
In the formula, S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.
[0221]
The number variation coefficient in the toner number particle size distribution is calculated from the following equation.
Number variation coefficient (%) = (S / Dn) × 100
In the formula, S represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm).
[0222]
The toner particles having no corners of the present invention refer to toner particles that substantially do not have projections that concentrate electric charges or projections that easily wear due to stress. Toner particles without toner. That is, as shown in FIGS. 1A, 1B, and 1C, a circle having a major axis of the toner particle L and a radius R of L / 10 is in contact with the toner particle peripheral line at one point. On the other hand, when the inside is rolled, the case where the circle does not substantially protrude outside the toner is referred to as toner particles having no corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.
[0223]
The measurement of toner without corners was performed as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.
[0224]
The toner of the present invention may be used as a one-component developer or a two-component developer.
When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.
[0225]
Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
[0226]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0227]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.
[0228]
The toner of the present invention includes a step of fixing a transfer material (also referred to as an image forming support or transfer paper) on which a toner image is formed between a heating roller and a pressure roller constituting a fixing device. It is used suitably for the image forming method containing.
[0229]
Next, although not limited to this, FIG. 2 shows an example of a configuration diagram showing an example of the image forming apparatus according to the present invention, and the image forming method of the present invention will be described.
[0230]
In FIG. 2, exposure light is emitted from the semiconductor laser light source 11 based on information read by a document reading device (not shown). This is distributed by the polygon mirror 12 in a direction perpendicular to the paper surface of FIG. 2, and is irradiated onto the surface of the photoreceptor through an fθ lens 13 that corrects image distortion to form an electrostatic latent image. The photoreceptor 14 is uniformly charged in advance by the charger 15 and starts rotating clockwise in accordance with the timing of image exposure.
[0231]
The electrostatic latent image on the surface of the photosensitive member is developed by the developing device 16 under reversal development conditions, and the formed developed image is transferred to the transfer member 18 conveyed in time by the action of the transfer device 17. . Further, the photosensitive member 14 and the transfer member 18 are separated by a separator (separation pole) 19, but the developed image is transferred and supported on the transfer member 18 and guided to the fixing device 40 and fixed.
[0232]
Untransferred toner or the like remaining on the surface of the photoreceptor is cleaned by a cleaning device 21 of a cleaning blade method, and the residual charge is removed by pre-charge exposure (PCL) 22, and again by the charger 15 for the next image formation. Uniformly charged.
[0233]
The transfer body P is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and of course includes an OHP PET base.
[0234]
The cleaning blade 23 uses a rubber-like elastic body having a thickness of about 1 to 30 mm, and urethane rubber is most often used as the material.
[0235]
In the image forming apparatus of the present invention, a process cartridge in which any one of a photoconductor and at least a charger, an image exposure device, a developing device, a transfer device, and a cleaning device is integrally configured is formed in the main body of the image forming device. It is also a preferable aspect to attach detachably.
[0236]
【Example】
Next, in order to demonstrate the effect of this invention concretely, it demonstrates in an Example, However, Of course, the aspect of this invention is not limited to these.
[0237]
Production example of calcium stearate
Calcium stearate 1-5
Solid content concentration 12.6% by mass, BET specific surface area 10m²/ G lime milk slurry was prepared. This lime milk slurry is wet-ground with a dyno mill (Simmer Enterprises Co., Ltd .: KDL-pilot type), and has a BET specific surface area of 20 m.²/ G, lime milk slurry with a sedimentation volume of 80 ml / 60 minutes. The lime milk slurry was dehydrated to a solid content concentration of 40%.
[0238]
Meanwhile, 570 g of stearic acid (neutralization number 197) heated and melted at 100 ° C. in a 3 liter kneader was prepared. Was added. This compounding ratio, when converted, is higher fatty acid / Ca (OH)₂/ Water (molar ratio) = 2 / 1.2 / 12.8. In this state, the mixture was mixed for 5 to 30 minutes to complete the reaction between stearic acid and calcium hydroxide.
[0239]
The reaction finished product was dried under reduced pressure at 100 ° C. to obtain calcium soap. When the obtained calcium soap was subjected to IR analysis, it was 1700 cm.^-1The peak of the carboxyl group of 1600cm^-1It was confirmed that calcium stearate was formed. Calcium stearate 1-5 shown in Table 1 was obtained by changing the reaction time and the drying time under reduced pressure.
[0240]
Calcium stearate 6
In the production of calcium stearate 1 to 5, calcium stearate 6 shown in Table 1 was obtained in the same manner except that 399 g of stearic acid and 171 g of palmitic acid were used instead of 570 g of stearic acid.
[0241]
[Table 1]

[0242]
Production example of inorganic / organic composite particles
Styrene-acrylic organic fine particles having an average particle diameter of 1.0 μm (electric resistance 6.6 × 10¹³40 g of titanium oxide particle trade name ET-300W (manufactured by Ishihara Sangyo Co., Ltd.) whose surface has a primary particle diameter of 30 nm was treated with 100 g of 100 Ω · cm) and mixed with a turbulent mixer. Next, the hybridizer (manufactured by Nara Machinery Co., Ltd.) with a modified pulverizer was treated for 3 minutes at a peripheral speed of 100 m / sec to produce inorganic / organic composite fine particles in which titanium oxide was fixed on the surface of the organic fine particles. This is designated as “inorganic / organic composite fine particle 1”.
[0243]
The electric resistance of the inorganic / organic composite fine particle 1 is 4.8 × 10⁸It was Ω · cm.
Production example of resin particles for toner
(Latex: 1HML)
(1) Preparation of core particles (first stage polymerization)
Surfactant prepared by dissolving 7.08 g of an anionic surfactant (sodium dodecyl sulfonate: SDS) in 3010 g of ion-exchanged water in a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device The solution (aqueous medium) was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0244]
To this surfactant solution, an initiator solution prepared by dissolving 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., and then 70.1 g of styrene, n -A monomer mixture composed of 19.9 g of butyl acrylate and 10.9 g of methacrylic acid was added dropwise over 1 hour, and this system was polymerized by heating and stirring at 75 ° C for 2 hours (first stage polymerization). And a latex (a dispersion of resin particles made of a high molecular weight resin) was prepared. This is referred to as “latex (1H)”.
[0245]
(2) Formation of intermediate layer (second stage polymerization)
In a flask equipped with a stirrer, 105.6 g of styrene, 30.0 g of n-butyl acrylate, 6.4 g of methacrylic acid, 5.6 g of n-octyl-3-mercaptopropionic acid ester, A compound represented by the formula 19) (hereinafter referred to as “exemplary compound (19)”) 72.0 g was added, heated to 80 ° C. and dissolved to prepare a monomer solution.
[0246]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (SDS) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and the latex (dispersed core particle) was added to the surfactant solution. 1H) was added in an amount of 28 g in terms of solid content, and then the monomer solution of the exemplified compound (19) was mixed and dispersed by a mechanical disperser “CLEARMIX” (manufactured by M-Technique) having a circulation path. Thus, a dispersion (emulsion) containing emulsion particles (oil droplets) having a uniform dispersion particle diameter (284 nm) was prepared.
[0247]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to this dispersion (emulsion), and the system was heated at 80 ° C. Polymerization (second stage polymerization) was carried out by heating and stirring for 3 hours to obtain latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin was coated with an intermediate molecular weight resin). This is referred to as “latex (1HM)”.
[0248]
(3) Formation of outer layer (third stage polymerization)
An initiator solution prepared by dissolving 7.4 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water is added to the latex (1HM) obtained as described above. A monomer mixed solution consisting of 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third-stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and latex (a central portion made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, A dispersion of composite resin particles) having an outer layer made of a molecular weight resin and containing the exemplified compound (19) in the intermediate layer was obtained. This latex is referred to as “latex (1HML)”.
[0249]
The composite resin particles constituting the latex (1HML) had peak molecular weights of 138,000, 80,000 and 13,000, and the number average particle diameter of the composite resin particles was 102 nm.
[0250]
[Preparation Example 2 for Composite Resin Particles]
(1) Preparation of core particles (first stage polymerization):
In a flask equipped with a stirrer, a compound “exemplary compound (16) represented by the above formula 16) was added to a monomer mixed solution composed of 105.6 g of styrene, 30.0 g of n-butyl acrylate, and 6.4 g of methacrylic acid. 72.0 g ") was added, and the solution was heated to 80 ° C and dissolved to prepare a monomer solution.
[0251]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (SDS) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and a mechanical disperser “Claire having a circulation path was added to the surfactant solution. Dispersion containing emulsified particles (oil droplets) having a uniform dispersed particle size (268 nm) by mixing and dispersing the monomer solution of the exemplified compound (16) by “CLEARMIX” (manufactured by M-Technique) (Emulsified liquid) was prepared.
[0252]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to this dispersion (emulsion), and the system was heated at 80 ° C. Polymerization (first stage polymerization) was carried out by heating and stirring for 3 hours to prepare latex (a dispersion of resin particles made of a high molecular weight resin). This is referred to as “latex (2H)”.
[0253]
(2) Formation of outer layer (second stage polymerization):
An initiator solution obtained by dissolving 14.8 g of a polymerization initiator (KPS) in 400 ml of ion-exchanged water is added to the latex (2H) obtained as described above, and 600 g of styrene under a temperature condition of 80 ° C. A monomer mixed solution consisting of 190 g of n-butyl acrylate, 30.0 g of methacrylic acid, and 20.8 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (second-stage polymerization) is performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and having a latex (a central portion made of a high molecular weight resin and an outer layer made of a low molecular weight resin). A dispersion of composite resin particles containing the exemplified compound (16) in the center was obtained. This latex is referred to as “latex (2HL)”.
[0254]
The composite resin particles constituting the latex (2HL) had peak molecular weights of 168,000 and 11,000, and the weight average particle size of the composite resin particles was 126 nm.
[0255]
[Production Examples 1 to 4 of colored particles]
59.0 g of sodium n-dodecyl sulfate was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring this solution, 420.0 g of carbon black “Regal 330” (Cabot Corporation) was gradually added, and then dispersed by using “Cleamix” (M-Technics Corporation) to give a coloring. A dispersion of agent particles (hereinafter referred to as “colorant dispersion”) was prepared. When the particle diameter of the colorant particles in this colorant dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 98 nm.
[0256]
420.7 g (in terms of solid content) of the latex (1HML) obtained in Preparation Example 1 for composite resin particles, 900 g of ion-exchanged water, and 166 g of a colorant dispersion liquid were mixed with a temperature sensor, a cooling tube, a nitrogen introducing device, and stirring. The mixture was stirred in a reaction vessel equipped with an apparatus, a particle size and shape monitoring device. After adjusting the internal temperature to 30 ° C., 5 mol / liter sodium hydroxide aqueous solution was added to this solution to adjust the pH to 11.0.
[0257]
Next, an aqueous solution in which 12.1 g of magnesium chloride hexahydrate was dissolved in 1000 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the temperature increase was started, and the system was heated to 90 ± 3 ° C. over 6 to 10 minutes (temperature increase rate = 10 ° C./min). In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II”, and when the volume average particle size became 5.5 μm, an aqueous solution in which 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. Was added to stop the particle growth, and the fusion was continued by agitating at a liquid temperature of 85 ± 2 ° C. for 0.5 to 15 hours as an aging treatment. Then, it cooled to 30 degreeC on the conditions of 8 degreeC / min, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped. The produced associated particles are filtered using a Nutsche, washed repeatedly with ion-exchanged water, then dried at a suction air temperature of 60 ° C. using a flash jet dryer, and then at a temperature of 60 ° C. using a fluidized bed dryer. It was dried to obtain colored particles containing the exemplified compound (19) as a release agent. In the monitoring of the salting-out / fusion stage and the shape control process, by controlling the number of revolutions of stirring and the heating time, the variation coefficient of the shape and the shape factor is controlled, and the variation coefficient of the particle size and the particle size distribution is arbitrarily set. By adjusting, colored particles 1 to 4 having shape characteristics and particle size distribution characteristics shown in Table 2 were obtained.
[0258]
[Production Examples 5 to 8 of colored particles]
Instead of latex (1HML), 420.7 g (converted to solid content) of latex (2HL) obtained in Preparation Example 2 of composite resin particles was used, and the aging treatment time was changed, and Colored Particle Production Examples 1 to 4, colored particles 5 to 8 having the shape characteristics and particle size distribution characteristics shown in Table 2 were obtained.
[0259]
[Table 2]

[0260]
Hydrophobic silica (number average primary particle size = 10 nm, hydrophobization degree = 63) is added to each of the colored particles 1 to 8 obtained as described above at a ratio of 1.0% by mass, and hydrophobic particles are added. Titanium oxide (number average primary particle size = 25 nm, hydrophobization degree = 60) was added at a ratio of 0.8% by mass and mixed with a Henschel mixer.
[0261]
Further, 0.01% by mass of calcium stearate shown in Table 3 and 1% by mass of inorganic / organic composite fine particles or strontium titanate were added and mixed with a Henschel mixer to prepare toners 1-12.
[0262]
A toner to which calcium stearate is not added is referred to as comparative toner 1. Further, for comparison, a toner to which zinc stearate (manufactured by NOF Corporation: zinc stearate D) is added is referred to as comparative toner 2.
[0263]
Note that the shape and particle size of these colored particles are not changed by the addition of an external additive.
[0264]
[Table 3]

[0265]
Carrier production
Manufacture of ferrite core particles
22 mol% of MnO, Fe₂O_Three78 mol% was pulverized, mixed and dried in a wet ball mill for 2 hours, and then temporarily calcined by holding at 900 ° C. for 2 hours, and this was pulverized in a ball mill for 3 hours to form a slurry. A dispersant and a binder were added, granulated and dried with a spray dryer, and then subjected to main firing at 1200 ° C. for 3 hours to obtain ferrite core particles having an average grain diameter of 5.2 μm and a resistance of 4.3 × 10 8.
[0266]
Resin coating
First, a cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5 /) was prepared by emulsion polymerization using a sodium benzenesulfonate having an alkyl group having 12 carbon atoms as a surfactant in an aqueous medium at a concentration of 0.3% by mass. 5), a volume average primary particle size of 0.1 μm, a weight average molecular weight (Mw) of 200,000, a number average molecular weight (Mn) of 91,000, Mw / Mn = 2.2, and a softening point temperature. (Tsp) 230 ° C. and glass transition temperature (Tg) 110 ° C. Resin fine particles were obtained. The resin fine particles azeotroped with water in the emulsified state, and the residual monomer amount was 510 ppm.
[0267]
Next, 100 parts by mass of ferrite core material particles and 2 parts by mass of the resin fine particles are put into a high-speed agitator / mixer with agitating blades, and agitated and mixed at 120 ° C. for 30 minutes to use the action of mechanical impact force. Thus, a resin-coated carrier having a volume average particle size of 61 μm was obtained.
[0268]
Production of developer
Each colored particle (toner) to which an external additive was added was mixed with a carrier to prepare a developer having a toner concentration of 6% by mass. These developers are referred to as developers 1 to 12 and comparative developers 1 and 2 corresponding to the colored particles 1 to 12 and the comparative colored particles 1 to 2, respectively.
[0269]
Manufacture of photoconductor
30 g of polyamide resin Amilan CM-8000 (manufactured by Toray Industries, Inc.) was put into a mixed solvent of 900 ml of methanol and 100 ml of 1-butanol and dissolved by heating at 50 ° C. This liquid was applied onto a cylindrical aluminum conductive support having an outer diameter of 60 mm and a length of 360 mm to form an intermediate layer having a thickness of 0.5 μm.
[0270]
Next, 10 g of silicone resin KR-5240 (manufactured by Shin-Etsu Chemical Co., Ltd.) is dissolved in 1000 ml of t-butyl acetate, and 10 g of Y-TiOPc (described in JP-A No. 64-17066, FIG. 1) is mixed therein and a sand mill is used. For 20 hours to obtain a charge generation layer coating solution. Using this solution, the charge generation layer having a thickness of 0.3 μm was formed on the intermediate layer.
[0271]
Next, 150 g of CTM (T-1: N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) and polycarbonate resin Iupilon Z-200 having a viscosity average molecular weight of 20,000. 200 g (Mitsubishi Gas Chemical Co., Ltd.) was dissolved in 1000 ml of 1,2-dichloroethane to obtain a charge transport layer coating solution. Using this solution, the charge generation layer was coated on a circular slide hopper and then dried at 100 ° C. for 1 hour to form a charge transport layer having a thickness of 22 μm. In this way, a photoreceptor (P1) composed of an intermediate layer, a charge generation layer, and a charge transport layer was obtained. Next, 30 g of CTM (T-1) and 50 g of polycarbonate resin Iupilon Z-800 (Mitsubishi Gas Chemical Co., Ltd.) having a viscosity average molecular weight of 80,000 are dissolved in 1000 ml of 1,2-dichloroethane on the surface of the photoreceptor (P1). Using the applied coating solution, a coating is applied on the charge transport layer with a circular slide hopper, followed by drying at 100 ° C. for 1 hour to form a 5 μm-thick overcoat layer to obtain a photoreceptor (P2). It was.
[0272]
Examples 1-12 and Comparative Examples 1 and 2
Using developers 1 to 12 and comparative developers 1 and 2, a modified digital camera equipped with a photoconductor (P2) mounted on a commercially available digital copying machine Konica, Sitos Konica 7030, under a high temperature and high humidity environment (temperature 33 ° C., At a relative humidity of 80%, an actual shooting test for continuously forming 300,000 images with a pixel rate of 15% was performed to evaluate the blade wear amount, chipping, image blur, and the environmental dependency of image density.
[0273]
In addition, it was set as Examples 1-12 and Comparative Examples 1 and 2 corresponding to the said developer No ..
[0274]
Blade wear amount
After printing 100,000 sheets, the cleaning blade was removed from the cleaning device, and the portion that disappeared due to wear was measured with a laser microscope. If the depletion amount is within 10 μm, the level is not problematic.
[0275]
Missing
Evaluation was made based on the number of the toner detected on the photoconductor from the cleaning device on the white background of the image and detected as image smear.
[0276]
Image blur
A character image having a character size of 5 points was formed on the entire surface of the image, and the evaluation was performed based on the number of images until the image was locally blurred or a portion where toner oozes around the image was detected.
[0277]
Environment dependence of image density
The maximum image density of the solid image portion was measured with a Macbeth reflection densitometer. The difference in image density between the high temperature and high humidity environment (33 ° C., 80% RH) and the low temperature and low humidity environment (10 ° C., 20% RH) is less than 0.05, “」 ”, 0.05-0.1 is“ ◯ ”, 0 .1 or more was designated as “x”.
[0278]
The results are shown in Table 4.
[0279]
[Table 4]

[0280]
It can be seen that Examples 1 to 12 in the present invention have no problem with any of the characteristics, but Comparative Example 1 or 2 outside the present invention has problems with any of the characteristics.
[0281]
【The invention's effect】
According to the present invention, it is possible to provide a method for increasing the durability of the photosensitive member itself, the electrostatic latent image developing toner acting on the photosensitive member, and the cleaning device during repeated use. More specifically, the toner for developing an electrostatic latent image eliminates image blurring caused by wear of the cleaning blade, toner slipping on the surface of the photosensitive member during cleaning, or toner fixation, and variations in image density due to the temperature and humidity environment during use. And an image forming method or an image forming apparatus using the same.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating toner particles having no corners.
FIG. 2 is a configuration diagram of an image forming apparatus.
[Explanation of symbols]
14 Photoconductor
15 Charger
16 Developer
17 Transfer device
18 Transcript
40 Fixing device

Claims (18)

  An electrostatic latent image developing toner obtained by forming toner particles in an aqueous medium, wherein the toner has a moisture content of 0.2 to 2.1% by mass and a free fatty acid content of 0.02. A toner for developing an electrostatic latent image, which comprises, as an external additive, a fatty acid calcium salt of ˜0.6% by mass.   2. The electrostatic latent image developing toner according to claim 1, wherein the fatty acid calcium salt is calcium stearate.   3. The electrostatic latent image developing toner according to claim 1, wherein the toner is obtained by aggregating and fusing at least resin particles in an aqueous medium.   The toner contains, as an external additive, inorganic / organic composite fine particles in which inorganic fine particles having a primary average particle size of 5 to 100 nm are fixed on the surface of organic fine particles having an average particle size of 0.1 to 5.0 μm. The electrostatic latent image developing toner according to claim 1, wherein the toner is an electrostatic latent image developing toner.   5. The number average particle diameter of the toner is 3 to 8 [mu] m, the variation coefficient of the shape factor is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less. The toner for developing an electrostatic latent image according to claim 1.   6. The toner according to claim 1, wherein the number average particle diameter of the toner is 3 to 8 [mu] m, and the ratio of the toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more. The electrostatic latent image developing toner according to claim 1.   6. The toner according to claim 1, wherein the number average particle diameter of the toner is 3 to 8 [mu] m, and the ratio of the toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more. The electrostatic latent image developing toner according to claim 1.   6. The electrostatic latent image developing device according to claim 1, wherein the number average particle diameter of the toner is 3 to 8 μm, and the ratio of toner particles having no corners is 50 number% or more. toner.   When the particle diameter of the toner is D (μm), the natural logarithm lnD is taken on the horizontal axis, and this horizontal axis is included in the most frequent class in the histogram showing the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of the toner particles and the relative frequency (m2) of the toner particles contained in the next most frequent class is 70% or more. The toner for developing an electrostatic latent image according to any one of claims 1 to 5.   6. The electrostatic latent image developing device according to claim 1, wherein the proportion of toner having no corners is 50% by number or more and the number variation coefficient in the number particle size distribution is 27% or less. toner.   The toner particles having a shape factor of 1.2 to 1.6 in a proportion of 65% by number or more and a variation coefficient of the shape factor of 16% or less. 6. The electrostatic latent image developing toner according to any one of 5 above.   The toner is obtained by salting out, aggregating and fusing the composite resin particles obtained by the multistage polymerization method and the colorant particles, and a release agent is contained in a region other than the outermost layer of the composite resin particles. The toner for developing an electrostatic latent image according to any one of claims 1 to 11, wherein the toner is used.   The toner resin having a peak or shoulder of gel permeation chromatography (GPC) at least 100,000 to 1,000,000 and 1,000 to 50,000 is used. The toner for developing an electrostatic latent image according to any one of the above.   Use a toner resin in which the peak or shoulder of gel permeation chromatography (GPC) is at least 100,000 to 1,000,000, 25,000 to 100,000, and 1,000 to 25,000. The electrostatic latent image developing toner according to claim 1, wherein the toner is an electrostatic latent image developing toner.   The electrostatic latent image developing toner according to claim 1, comprising a resin, a release agent, and a colorant, and a crushing strength index of 0.1 to 0.8. The electrostatic latent image formed on the organic photoconductor is developed with a developer containing toner, and the toner image visualized by the development is transferred from the organic photoconductor to a transfer material, and then is transferred onto the organic photoconductor. 16. An image forming method comprising a cleaning unit for removing residual toner, wherein the toner according to claim 1 is used. 17. The image according to claim 16, wherein the organic photoreceptor has a constitution in which a photosensitive layer is provided on a conductive support, and the surface layer of the photosensitive layer contains a polycarbonate having an average molecular weight of 40,000 or more. Forming method. 2. The toner for developing an electrostatic latent image according to claim 1, wherein at least toner particles are formed by forming particles in an aqueous medium, and after the particles are dried, 0.3 to 1.2% by mass of fatty acid calcium salt particles are externally added. A method for producing a toner for developing an electrostatic latent image, wherein:

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