JP4063059B2 - Toner for developing electrostatic image, method for producing toner for developing electrostatic image, image forming method and image forming apparatus using the same - Google Patents

Description

【０１３１】
【化２】

【０１３２】
上記化合物の添加量は、着色粒子全体に対し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。
【０１３３】
本発明に係る着色粒子では、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。
【０１３４】
（荷電制御剤）
着色粒子は、着色剤、離型剤以外に着色粒子用材料として種々の機能を付与することのできる材料を添加することができる。具体的には、荷電制御剤等が挙げられる。これらの成分は前述の塩析／融着段階で樹脂粒子と着色剤粒子と同時に添加し、着色粒子中に包含する方法、樹脂粒子自体に添加する方法等種々の方法で添加することができる。
【０１３５】
荷電制御剤は、種々の公知のもので、且つ水中に分散することができるものを使用することができる。具体的には、ニグロシン系染料、ナフテン酸又は高級脂肪酸の金属塩、アルコキシル化アミン、第４級アンモニウム塩化合物、アゾ系金属錯体、サリチル酸金属塩あるいはその金属錯体等が挙げられる。
【０１３６】
（外添剤）
本発明のトナーは、着色粒子をそのまま使用してもよいが、流動性の改良やクリーニング性の向上などの目的で、いわゆる外添剤を着色粒子に添加して使用することがより好ましい。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。
【０１３７】
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。
【０１３８】
シリカ微粒子の具体例としては、日本アエロジル（株）製の市販品Ｒ−８０５、Ｒ−９７６、Ｒ−９７４、Ｒ−９７２、Ｒ−８１２、Ｒ−８０９、ヘキスト（株）製のＨＶＫ−２１５０、Ｈ−２００、キャボット（株）製の市販品ＴＳ−７２０、ＴＳ−５３０、ＴＳ−６１０、Ｈ−５、ＭＳ−５等が挙げられる。
【０１３９】
チタン微粒子の具体例としては、例えば、日本アエロジル（株）製の市販品Ｔ−８０５、Ｔ−６０４、テイカ（株）製の市販品ＭＴ−１００Ｓ、ＭＴ−１００Ｂ、ＭＴ−５００ＢＳ、ＭＴ−６００、ＭＴ−６００ＳＳ、ＪＡ−１、富士チタン（株）製の市販品ＴＡ−３００ＳＩ、ＴＡ−５００、ＴＡＦ−１３０、ＴＡＦ−５１０、ＴＡＦ−５１０Ｔ、出光興産（株）製の市販品ＩＴ−Ｓ、ＩＴ−ＯＡ、ＩＴ−ＯＢ、ＩＴ−ＯＣ等が挙げられる。
【０１４０】
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（株）製の市販品ＲＦＹ−Ｃ、Ｃ−６０４、石原産業（株）製の市販品ＴＴＯ−５５等が挙げられる。
【０１４１】
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。
【０１４２】
外添剤として使用できる滑剤としては、高級脂肪酸の金属塩を挙げることができる。かかる高級脂肪酸の金属塩の具体例としては、ステアリン酸亜鉛、ステアリン酸アルミニウム、ステアリン酸銅、ステアリン酸マグネシウム、ステアリン酸カルシウム等のステアリン酸金属塩；オレイン酸亜鉛、オレイン酸マンガン、オレイン酸鉄、オレイン酸銅、オレイン酸マグネシウム等のオレイン酸金属塩；パルミチン酸亜鉛、パルミチン酸銅、パルミチン酸マグネシウム、パルミチン酸カルシウム等のパルミチン酸金属塩；リノール酸亜鉛、リノール酸カルシウム等のリノール酸金属塩；リシノール酸亜鉛、リシノール酸カルシウムなどのリシノール酸金属塩等が挙げられる。
【０１４３】
外添剤の添加量としては、着色粒子に対して０．１〜５質量％程度であることが好ましい。
【０１４４】
〈外添剤の添加工程〉
この工程は、乾燥処理された着色粒子に外添剤を添加する工程である。
【０１４５】
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。
【０１４６】
（トナー粒子）
本発明のトナーの粒径は、個数平均粒径で３〜１０μｍであることが好ましく、より好ましくは３〜８μｍとされる。この粒径は、着色粒子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。
【０１４７】
尚、外添剤の粒子は非常に微粒子なので、着色粒子に外添剤を添加して得られたトナーと着色粒子そのままの粒径は、測定結果ほぼ同じである。
【０１４８】
個数平均粒径が３〜１０μｍ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定着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、又、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。
【０１４９】
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」（コールター株式会社製）、レーザー回折式粒径測定装置「ＳＬＡＤ１１００」（島津製作所株式会社製）等を用いて測定することができる。
【０１５０】
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」（日科機株式会社製）、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。
【０１５１】
（現像剤）
本発明のトナーは、一成分現像剤として、或いは二成分現像剤として用いることができる。
【０１５２】
一成分現像剤としては、具体的には非磁性一成分現像剤、或いはトナー中に０．１〜０．５μｍ程度の磁性粒子を含有させ磁性一成分現像剤が挙げられ、いずれも用いることができる。
【０１５３】
又、このトナーは、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でき、これらの中ではフェライト粒子が好ましい。上記磁性粒子の体積平均粒径は１５〜１００μｍのものが好ましく、２５〜８０μｍのものがより好ましい。
【０１５４】
キャリアの体積平均粒径の測定は、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」（シンパティック株式会社製）により測定することができる。
【０１５５】
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。被覆用の樹脂としては、特に限定されず公知のものを使用することができ、具体的には、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。又、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、具体的には、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。
【０１５６】
（画像形成方法）
次に、本発明のトナーを用いる画像形成方法及び画像形成装置について説明する。
【０１５７】
図１は、本発明のトナーを用いる画像形成方法の一例を示す画像形成装置の断面構成図である。
【０１５８】
図１に示す画像形成装置は、デジタル方式による画像形成装置であって、画像読取り部Ａ、画像処理部Ｂ（図示省略）、画像形成部Ｃ、転写紙搬送手段としての転写紙搬送部Ｄから構成されている。
【０１５９】
画像読取り部Ａの上部には原稿を自動搬送する自動原稿送り手段が設けられていて、原稿載置台１１１上に載置された原稿は原稿搬送ローラ１１２によって１枚宛分離搬送され読み取り位置１１３ａにて画像の読み取りが行われる。原稿読み取りが終了した原稿は原稿搬送ローラ１１２によって原稿排紙皿１１４上に排出される。
【０１６０】
一方、プラテンガラス１１３上に置かれた場合の原稿の画像は走査光学系を構成する照明ランプ及び第１ミラーから成る第１ミラーユニット１１５の速度ｖによる読み取り動作と、Ｖ字状に位置した第２ミラー及び第３ミラーから成る第２ミラーユニット１１６の同方向への速度ｖ／２による移動によって読み取られる。
【０１６１】
読み取られた画像は、投影レンズ１１７を通してラインセンサである撮像素子ＣＣＤの受光面に結像される。撮像素子ＣＣＤ上に結像されたライン状の光学像は順次電気信号（輝度信号）に光電変換されたのちＡ／Ｄ変換を行い、画像処理部Ｂにおいて濃度変換、フィルタ処理などの処理が施された後、画像データは一旦メモリに記憶される。
【０１６２】
画像形成部Ｃでは、画像形成ユニットとして、像担持体であるドラム状の感光体（以下、感光体ドラムとも云う）１２１と、その外周に、帯電手段である帯電器１２２、現像手段である現像装置１２３、転写手段である転写器１２４、分離手段である分離器１２５、クリーニング装置（ブレードクリーニング）１２６及びＰＣＬ（プレチャージランプ）１２７が各々動作順に配置されている。感光体１２１は、光導電性化合物をドラム基体上に塗布形成したもので、例えば有機感光体（ＯＰＣ）が好ましく使用され、図示の時計方向に駆動回転される。
【０１６３】
回転する感光体１２１へは帯電器１２２による一様帯電がなされた後、露光光学系１３０により画像処理部Ｂのメモリから呼び出された画像信号に基づいた像露光が行われる。書き込み手段である露光光学系１３０は図示しないレーザーダイオードを発光光源とし、回転するポリゴンミラー１３１、ｆθレンズ（符号なし）、シリンドリカルレンズ（符号なし）を経て反射ミラー１３２により光路が曲げられ主走査がなされるもので、感光体１２１に対してＡｏの位置において像露光が行われ、感光体１２１の回転（副走査）によって潜像が形成される。本実施の形態の一例では文字部に対して露光を行い潜像を形成する。
【０１６４】
感光体１２１上の潜像は現像装置１２３によって反転現像が行われ、感光体１２１の表面に可視像のトナー像が形成される。転写紙搬送部Ｄでは、画像形成ユニットの下方に異なるサイズの転写紙Ｐが収納された転写紙収納手段としての給紙ユニット１４１（Ａ）、１４１（Ｂ）、１４１（Ｃ）が設けられ、又側方には手差し給紙を行う手差し給紙ユニット１４２が設けられていて、それらの何れかから選択された転写紙Ｐは案内ローラ１４３によって搬送路１４０に沿って給紙され、給紙される転写紙の傾きと偏りの修正を行うレジストローラ対１４４によって転写紙Ｐは一時停止を行ったのち再給紙が行われ、搬送路１４０、転写前ローラ１４３ａ及び転写進入ガイド板１４６に案内され、感光体１２１上のトナー画像が転写位置Ｂｏにおいて転写器１２４によって転写紙Ｐに転写され、次いで分離器１２５によって除電されて転写紙Ｐは感光体１２１面より分離し、搬送装置１４５により定着器１５０に搬送される。
【０１６５】
定着器１５０は定着ローラ１５１と加圧ローラ１５２とを有しており、転写紙Ｐを定着ローラ１５１と加圧ローラ１５２との間を通過させることにより、加熱、加圧によってトナーを熔着させる。トナー画像の定着を終えた転写紙Ｐは、排紙トレイ１６４上に排出される。
【０１６６】
【実施例】
以下に、実施例を挙げて具体的に説明するが、本発明の実施態様はこれらに限定されるものではない。
【０１６７】
《着色粒子１の調製》
（大粒径ラテックス（１ＨＭＬ）の調製）
〈１：樹脂粒子の調製（１段目の重合）〉
攪拌装置、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Ａ（Ｃ₁₀Ｈ₂₁（ＯＣＨ₂ＣＨ₂）₂ＯＳＯ₃Ｎａ）２．５ｇをイオン交換水３０４０ｇに溶解した界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの攪拌速度で攪拌しながら、内温を８０℃に昇温した。
【０１６８】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）１０．０ｇをイオン交換水４００ｇに溶解した開始剤溶液を添加し、温度を７５℃とした後、スチレン５２８ｇ、ｎ−ブチルアクリレート２０４ｇ、メタクリル酸６８．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル２４．４ｇからなる単量体混合液を１時間かけて低速で撹拌している液中に滴下した。この系を７５℃にて２時間にわたり加熱、攪拌することにより重合（１段目の重合）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「大粒径ラテックス（１Ｈ）」とする。
【０１６９】
〈２：中間層の形成（２段目の重合）〉
攪拌装置を取り付けたフラスコ内において、スチレン９５．０ｇ、ｎ−ブチルアクリレート３６．０ｇ、メタクリル酸９．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル０．５９ｇからなる単量体混合液に、離型剤として前記例示化合物１９）を７７ｇ添加し、９０℃で加温、溶解して「単量体溶液１」を調製した。
【０１７０】
次いで、上記アニオン系界面活性剤Ａの０．８ｇを、イオン交換水１５６０ｍｌに溶解した界面活性剤溶液を９８℃に加熱し、この界面活性剤溶液に、樹脂粒子の分散液である「大粒径ラテックス（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」（エム・テクニック株式会社製）により、上記調製した「単量体溶液１」を８時間混合分散し、均一な分散粒子径を有する乳化粒子（油滴）を含む乳化液を調製した。
【０１７１】
次いで、この乳化液に重合開始剤（ＫＰＳ）５．０ｇをイオン交換水２００ｍｌに溶解した開始剤溶液とイオン交換水７５０ｍｌとを添加し、この系を９８℃にて１２時間にわたり加熱攪拌することにより重合（２段目の重合）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「大粒径ラテックス（１ＨＭ）」とする。
【０１７２】
〈３：外層の形成（第３段目の重合）〉
上記調製した「大粒径ラテックス（１ＨＭ）」に、重合開始剤（ＫＰＳ）６．８ｇをイオン交換水２６５ｍｌに溶解した開始剤溶液を添加し、８０℃の温度条件下で、スチレン２４９ｇ、ｎ−ブチルアクリレート８８．２ｇ、メタクリル酸１９．４ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル７．４５ｇ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時間にわたり加熱攪拌することにより重合（３段目の重合）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する）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「大粒径ラテックス（１ＨＭＬ）」とする。
【０１７３】
「大粒径ラテックス（１ＨＭＬ）」の粒子径を「マイクロトラック ＵＰＡ−１５０」（日機装株式会社製）で測定し、ピークを求めたところ、ピークは質量平均で７００ｎｍであった。
【０１７４】
（小粒径ラテックス（１ＨＭＬ）の調製）
〈１：樹脂粒子の調製（１段目の重合）〉
攪拌装置、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Ａ（Ｃ₁₀Ｈ₂₁（ＯＣＨ₂ＣＨ₂）₂ＯＳＯ₃Ｎａ）５．０ｇをイオン交換水３０４０ｇに溶解した界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの攪拌速度で攪拌しながら、内温を８０℃に昇温した。
【０１７５】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）１０．０ｇをイオン交換水４００ｇに溶解した開始剤溶液を添加し、温度を７５℃とした後、スチレン５２８ｇ、ｎ−ブチルアクリレート２０４ｇ、メタクリル酸６８．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル２４．４ｇからなる単量体混合液を１時間かけて高速で撹拌している液中に滴下した。この系を７５℃にて２時間にわたり加熱、攪拌することにより重合（第１段目の重合）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「小粒径ラテックス（１Ｈ）」とする。
【０１７６】
〈２：中間層の形成（２段目の重合）〉
攪拌装置を取り付けたフラスコ内において、スチレン９５．０ｇ、ｎ−ブチルアクリレート３６．０ｇ、メタクリル酸９．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル０．５９ｇからなる単量体混合液に、離型剤として前記例示化合物１９）を７７ｇ添加し、９０℃で加温、溶解して「単量体溶液１」を調製した。
【０１７７】
次いで、上記アニオン系界面活性剤Ａの１．５ｇを、イオン交換水１５６０ｍｌに溶解した界面活性剤溶液を９８℃に加熱し、この界面活性剤溶液に、樹脂粒子の分散液である「小粒径ラテックス（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」（エム・テクニック株式会社製）により、上記調製した「単量体溶液１」を８時間混合分散し、均一な分散粒子径を有する乳化粒子（油滴）を含む乳化液を調製した。
【０１７８】
次いで、この乳化液に重合開始剤（ＫＰＳ）５．０ｇをイオン交換水２００ｍｌに溶解した開始剤溶液とイオン交換水７５０ｍｌとを添加し、この系を９８℃にて１２時間にわたり加熱攪拌することにより重合（２段目の重合）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「小粒径ラテックス（１ＨＭ）」とする。
【０１７９】
〈３：外層の形成（３段目の重合）〉
上記調製した「小粒径ラテックス（１ＨＭ）」に、重合開始剤（ＫＰＳ）６．８ｇをイオン交換水２６５ｍｌに溶解した開始剤溶液を添加し、８０℃の温度条件下で、スチレン２４９ｇ、ｎ−ブチルアクリレート８８．２ｇ、メタクリル酸１９．４ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル７．４５ｇ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時間にわたり加熱攪拌することにより重合（３段目の重合）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、中間層に離型剤として例示化合物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「小粒径ラテックス（１ＨＭＬ）」とする。
【０１８０】
「小粒径ラテックス（１ＨＭＬ）」の粒径を「マイクロトラック ＵＰＡ−１５０」（日機装株式会社製）で測定し、ピークを求めたところ、ピークは質量平均で１２０ｎｍであった。
【０１８１】
（ラテックス（２Ｌ）の調製）
攪拌装置を取り付けたフラスコ内に、重合開始剤（ＫＰＳ）１４．８ｇをイオン交換水４００ｍｌに溶解した開始剤溶液を添加し、８０℃の温度条件下で、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時間にわたり加熱攪拌することにより重合を行った後、２８℃まで冷却し、ラテックス（低分子量樹脂からなる樹脂粒子の分散液）を得た。このラテックスを「ラテックス（２Ｌ）」とする。
【０１８２】
この「ラテックス（２Ｌ）」を構成する樹脂粒子は、１１，０００に分子量ピークを有するものであり、又、この樹脂粒子の粒径を「マイクロトラック ＵＰＡ−１５０」（日機装株式会社製）で測定したところ、質量平均粒径は１２０ｎｍであった。
【０１８３】
（着色剤分散液（１）の調製）
アニオン界面活性剤（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、この溶液を撹拌しながら、カーボンブラック４２０．０ｇを徐々に添加し、次いで分散機「クレアミックス」（エム・テクニック株式会社製）を用いて分散処理することにより、着色剤を分散した「着色剤分散液（１）」を調製した。
【０１８４】
（凝集・融着工程）
前記調製した「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）と、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）と、イオン交換水９００ｇと、上記調製した「着色剤分散液（１）」２００ｇとを、温度センサー、冷却管、窒素導入装置、攪拌装置を取り付けた反応容器（四つ口フラスコ）に入れ攪拌した。容器内の温度を３０℃に調整した後、この溶液に５モル／Ｌの水酸化ナトリウム水溶液を加えてｐＨを９．０に調整した。
【０１８５】
次いで、塩化マグネシウム・６水和物の１２．１ｇをイオン交換水１０００ｍｌに溶解した水溶液を、攪拌下で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、この水溶液を６０分間かけて９０℃まで昇温し、粒子の成長を開始した。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５．０μｍになった時点で、停止剤として塩化ナトリウムの４０．２ｇ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た。さらに、熟成処理として、液温度９８℃にて２時間にわたり加熱攪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℃まで冷却した。
【０１８６】
（シェリング工程）
上記により、凝集・融着を行った粒子に、前記調製した「ラテックス（２Ｌ）」９６ｇを添加し、３時間に亘り加熱、攪拌を継続し、「大粒径ラテックス（１ＨＭＬ）」と「小粒径ラテックス（１ＨＭＬ）」の凝集粒子表面に「ラテックス（２Ｌ）」をシェリングさせた。次いで、塩化ナトリウム４０．２ｇを添加し、８℃／分の降温条件で３０℃まで冷却し、次いで、塩酸を添加してｐＨを２．０に調整して、攪拌を停止した。
【０１８７】
以上のようにしてシェリングした融着粒子を濾過し、４５℃のイオン交換水で繰り返し洗浄し、その後、４０℃の温風で乾燥することにより、「着色粒子１」を調製した。
【０１８８】
このようにして調製された「着色粒子１」の体積平均粒径は６．４μｍ、当該「着色粒子１」を構成する樹脂の質量平均分子量は５５，０００、当該樹脂のガラス転移温度（Ｔｇ）は５７℃、当該樹脂の軟化点は１２５℃であった。
《着色粒子２の調製》
「着色粒子１の調製」において、「大粒径ラテックス（１ＨＭＬ）」と、「小粒径ラテックス（１ＨＭＬ）」の混合量を、「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）から４２ｇ（固形分換算）へ、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）を３７８ｇ（固形分換算）へ変更した以外は「着色粒子１の調製」と同様にして「着色粒子２」を調製した。
《着色粒子３の調製》
「着色粒子１の調製」において、「大粒径ラテックス（１ＨＭＬ）」と、「小粒径ラテックス（１ＨＭＬ）」の混合量を、「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）から８．４ｇ（固形分換算）へ、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）を４１１．６ｇ（固形分換算）へ変更した以外は「着色粒子１の調製」と同様にして「着色粒子３」を調製した。
《着色粒子４の調製》
「着色粒子１の調製」において、「大粒径ラテックス（１ＨＭＬ）」と、「小粒径ラテックス（１ＨＭＬ）」の混合量を、「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）から２．１ｇ（固形分換算）へ、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）を４１７．９ｇ（固形分換算）へ変更した以外は「着色粒子１の調製」と同様にして「着色粒子４」を調製した。
《着色粒子５の調製》
「着色粒子１の調製」において、「大粒径ラテックス（１ＨＭＬ）」と、「小粒径ラテックス（１ＨＭＬ）」の混合量を、「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）から１６８ｇ（固形分換算）へ、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）を２５２ｇ（固形分換算）へ変更した以外は「着色粒子１の調製」と同様にして「着色粒子５」を調製した。
《着色粒子６の調製》
「着色粒子１の調製」において、「大粒径ラテックス（１ＨＭＬ）」と、「小粒径ラテックス（１ＨＭＬ）」の混合量を、「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）から０ｇ（固形分換算）へ、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）を４２０ｇ（固形分換算）へ変更した以外は「着色粒子１の調製」と同様にして「着色粒子６」を調製した。
《着色粒子７の調製》
「着色粒子１の調製」において、「大粒径ラテックス（１ＨＭＬ）」と、「小粒径ラテックス（１ＨＭＬ）」の混合量を、「大粒径ラテックス（１ＨＭＬ）」８４ｇ（固形分換算）から４２０ｇ（固形分換算）へ、「小粒径ラテックス（１ＨＭＬ）」３３６ｇ（固形分換算）を０ｇ（固形分換算）へ変更した以外は「着色粒子１の調製」と同様にして「着色粒子７」を調製した。
【０１８９】
《トナー、現像剤の調製》
上記で調製した「着色粒子１〜７」に、それぞれ疎水性シリカ（数平均一次粒子径：１２ｎｍ、疎水化度：６８）を１．０質量％及び疎水性酸化チタン（数平均一次粒子径：２０ｎｍ、疎水化度：６３）を１．２質量％添加し、ヘンシェルミキサーにより混合して、「トナー１〜７」を調製した。
【０１９０】
次いで、上記で調製した各トナーに対して、シリコーン樹脂を被覆した体積平均粒子径６０μｍのフェライトキャリアを混合し、それぞれトナー濃度が６％の「現像剤１〜７」を調製した。
【０１９１】
尚、着色粒子中の平均離型剤のドメイン径は前記「スピカ」で解析して算出、着色粒子の粒径は前記「コールターマルチサイザー」を用いて測定した。
【０１９２】
表１に着色粒子の添加、ラテックス粒子のピーク、離型剤を含有する全ラテックス中の大粒径ラテックス量、離型剤ドメイン径の大きさ、着色粒子粒径を示す。
【０１９３】
【表１】

【０１９４】
《評価結果》
〈耐定着オフセット性評価〉
デジタル複写機「７０６５」（コニカ株式会社製）を改造し、下記条件にて上記で調製した「トナー１〜７」の定着オフセットと定着ローラのトナー汚れ評価を行った。
【０１９５】
定着装置は定着ローラに接触しているクリーニング機構等を全て取り外し、定着ローラへは何も接触しないように改造した。複写環境は常温常湿（２５℃、５５％ＲＨ）に設定し、装備されている定着用の定着ローラの表面温度（ローラの中心部で測定）を１５０〜１８０℃の範囲で、１０℃刻みで変化させ、各表面温度において、搬送方向に直交する位置に５ｍｍ幅のベタ黒帯状画像を有するＡ４サイズの普通紙を縦送りで搬送定着した後、搬送方向に直交する位置に５ｍｍ幅のベタ黒帯状画像と２０ｍｍ幅のハーフトーン画像を有するＡ４サイズの普通紙を横送りで搬送し、得られた各サンプルについて、定着オフセットに起因する画像汚れ（定着オフセット）及び定着ローラ表面のトナー汚れを目視観察し、下記の基準に則り耐定着オフセット性の評価を行った。
【０１９６】
◎：定着オフセット及び定着ローラ表面のトナー汚れとも、全く発生は認められない
○：定着オフセット及び定着ローラ表面のトナー汚れとも、ほぼ発生は認められない
△：定着オフセットの発生は認められないが、定着ローラ表面のトナー汚れが認められる
×：定着オフセット及び定着ローラ表面のトナー汚れの発生が認められる
××：明らかな定着オフセットの発生が認められ、更に定着ローラ表面のトナー汚れが著しい
上記評価ランクにおいて、◎及び○が実用上許容の範囲にあると判定した。
【０１９７】
〈画像評価〉
トナーをリサイクル使用するデジタル複写機「コニカ７０６５」（コニカ株式会社製）を改造し、定着器の定着ローラ表面温度を１７０℃に設定した評価機を用い、常温常湿（２０℃、５５％ＲＨ）の環境下、上記で調製した「トナー１〜７」と「現像剤１〜７」を用い、画素率が７％のＡ４版画像を普通紙（６４ｇ／ｍ²）に連続して１０万枚プリントを行った。
【０１９８】
初期の画像かぶりは、１０枚目プリントの非画像部のかぶりをルーペで評価した。
【０１９９】
定着ローラの定着オフセット汚染による画像かぶりは画像かぶりが発生した枚数で評価した。又、連続プリント中に発生した画像かぶりは画像かぶりが発生した枚数、画像濃度は１０万枚プリント終了後のプリントの濃度で評価した。
【０２００】
尚。かぶりは目視にて評価し、画像濃度は「マクベス濃度計」（マクベス株式会社製）で測定した。
【０２０１】
表２に、定着ローラの表面温度を変えたときの定着オフセットの発生状況、初期画像かぶり、定着ローラ汚染による画像かぶり発生枚数、連続プリントでの画像かぶり発生枚数、１０万枚プリント後の画像濃度を示す。
【０２０２】
【表２】

【０２０３】
表２から明らかなように、本発明の「トナー１〜４」は、比較例の「トナー５〜７」に比較し、定着オフセットの発生しない定着温度範囲が広く、初期画像かぶりが少なく、連続プリントしても定着ローラ汚染による画像かぶりが発生せず、現像剤劣化によるかぶりや濃度低下が発生せず耐久性に優れた効果を有する。
【０２０４】
【発明の効果】
実施例で実証したごとく、本発明のトナー、該トナーの製造方法、それを用いた画像形成方法及び画像形成装置は、定着オフセットが発生しない温度領域が広く、初期画像かぶりが無く、且つ、大量のプリントを行っても高画質（画像かぶり、画像濃度低下）の画像が継続して得られる優れた効果を有する。
【図面の簡単な説明】
【図１】本発明のトナーを用いる画像形成方法の一例を示す画像形成装置の断面構成図である。
【符号の説明】
１２１ 感光体
１２２ 帯電器
１２３ 現像装置
１２４ 転写器
１２５ 分離器
１２６ クリーニング装置
１２７ ＰＣＬ（プレチャージランプ）
１３０ 露光光学系
１５１ 定着器
Ｐ 転写紙[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner for developing an electrostatic image with improved fixing offset, image fogging, and durability, a method for producing the toner for developing an electrostatic image, an image forming method and an image forming apparatus using the same.
[0002]
[Prior art]
In digital copiers and laser printers that employ oil-les fixing with high image quality, there is no fixing offset, there is no image fogging, and in order to continuously obtain high-quality images even after a large amount of printing, It is important that the toner has a small particle size, the release agent is effectively eluted from the toner particles at the time of fixing, there is no free colorant on the surface of the toner particles, and the toner particles are not crushed in the developing process or the like. It is a problem.
[0003]
In general, a release agent is used in order to widen the temperature range in which fixing offset does not occur and to prevent image smear due to fixing offset. However, if a release agent is included in the toner particles in a large amount to achieve the above-mentioned purpose, the toner particles are easily crushed, and the ultrafine particles generated by the crushing contaminate the surface of the carrier and continue high-quality images. Will not be obtained.
[0004]
In response to such demands, it has been studied to include a release agent in the toner particles even for the polymerized toner, and during the polymerization step, the resin particles and the release agent particles are associated to prepare a release agent-containing polymerized toner. Has been done. However, in the toner obtained by this method, a sufficient amount of the release agent cannot be introduced into the associated particles (colored particles), and the content of the release agent is increased between the formed associated particles. Variation occurs, and the toner as a whole cannot exhibit sufficient fixing offset resistance.
[0005]
In order to solve these problems, techniques for improving a compound used in a release agent (see, for example, Patent Document 1) and increasing the amount added to a toner have been studied. However, resin particles and a release agent have been studied. The release agent is liberated from the associated particles due to the structural reason that the particles are associated with the particles, and the release agent deteriorates the developer, reduces the fluidity of the toner, and the photosensitive member. There is a problem of toner filming on the surface.
[0006]
Further, focusing on the toner particle structure, a toner having a sea-island structure in which the release agent phase is phase-separated in the binder resin phase in the toner particle structure is disclosed (for example, see Patent Documents 2, 3, and 4). However, these patents do not mention that there is a variation in the amount of the release agent added in the toner particles, and nothing is suggested about sufficiently controlling this variation. There wasn't. The toners disclosed in these patents have a structure in which the release agent is agglomerated in the center of the toner particles, although the release agent has a phase-separated structure. The structure is difficult to effectively exude to the outside of the toner particles, and the amount of the release agent added to the toner particles must be increased, and a distance is required until the release agent exudes to the outside of the toner. It was difficult for the release agent to bleed out to the outside at the time of fixing, and sufficient improvement in fixing offset could not be achieved.
[0007]
To solve the above problems, the binder resin and polypropylene form a sea-island structure in the toner cross section, and the maximum diameter in the major axis direction of the island-shaped portion formed by the polypropylene is 200 to 3000 mm. A toner having an average interval of 1 μm or less is disclosed (for example, see Patent Document 5).
[0008]
Patents relating to domains (islands) of release agents made of crystalline compounds have been disclosed (see, for example, Patent Documents 6 and 7).
[0009]
However, although these techniques are excellent in high-speed fixing properties, since a release agent domain exists on the toner surface, an image having a high charge resolution distribution and high resolution cannot be obtained. In addition, since the external additive attached to the island portion constituted by the release agent having a high hardness ester group on the toner surface is buried under stress, the development characteristics and transfer characteristics are unstable, and the intermediate tone There was a defect such as unevenness in the image (also called halftone). Further, it was detached, and the developing roller, photoconductor and transfer member were contaminated. On the other hand, there is a problem that uneven gloss occurs in a fixed image.
[0010]
In addition, as for the colorant, a patent is disclosed in which a dry powder colorant is uniformly dispersed by applying energy such as mechanical dispersion and ultrasonic dispersion, and then dispersed in toner particles (for example, patent documents). 8). However, in this method, the energy applied to disperse the colorant tends to be non-uniform, so that the dispersed particle size of the colorant is difficult to become fine and the distribution of the dispersed particle size tends to be broad. As a result, the colorant is not uniformly dispersed in the formed toner particles, and there is a colorant attached to the surface of the toner particles. When printing using this toner, the colorant adheres to the transfer paper and image fogging occurs, or if the colorant adheres to the surface of the carrier, the charge amount of the toner cannot be stably controlled, resulting in a high-quality image. Can not be obtained continuously.
[0011]
No toner has yet been developed to produce a high-quality (no fogging, high density) image even after continuous printing without fixing offset and image fog. is there.
[0012]
[Patent Document 1]
JP-A-8-41468
[0013]
[Patent Document 2]
JP-A-3-296067
[0014]
[Patent Document 3]
Japanese Patent Laid-Open No. 10-161338
[0015]
[Patent Document 4]
Japanese Patent Laid-Open No. 5-88409
[0016]
[Patent Document 5]
JP-A-3-296067
[0017]
[Patent Document 6]
JP-A-9-288372
[0018]
[Patent Document 7]
JP-A-9-292722
[0019]
[Patent Document 8]
JP 2001-08736 A
[0020]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above-described problems. The object of the present invention is to provide a wide temperature range where no fixing offset occurs, no initial image fogging, and high image quality even when a large amount of printing is performed. Provided is an electrostatic charge image developing toner (hereinafter also simply referred to as toner) that can continuously obtain a high density image without image fogging, a method for producing the toner, an image forming method and an image forming apparatus using the toner. There is to do.
[0021]
[Means for Solving the Problems]
The object of the present invention is achieved by adopting the following configuration.
[0022]
  1. In the electrostatic image developing toner having colored particles containing at least a resin, a colorant and a release agent, the colored particles areContains release agentThe latex particles are produced by agglomeration of latex particles, and the latex particles are a mixture of particles each having a peak in the range of at least 50 to 200 nm and 300 to 3000 nm, and the latex particle having a peak in the range of 300 to 3000 nm is obtained.Contains release agentA toner for developing an electrostatic charge image, which is 0.5 to 30% by mass of the total latex particles.
[0024]
  2. A method for producing a toner for developing an electrostatic image having colored particles containing at least a resin, a colorant and a release agent.Contains release agentThe latex particles are produced by agglomeration of latex particles. The latex particles are prepared separately from those having a peak in the range of 50 to 200 nm and those having a peak in the range of 300 to 3000 nm, and peak in the range of 300 to 3000 nm. Latex particles havingContains release agentBlended to make 0.5-30% by weight of all latex particlesMakeA method for producing a toner for developing an electrostatic charge image.
[0025]
  3. In an image forming method for forming an image through each step of charging, image exposure, development, thermal fixing, and a step where blade cleaning is added as necessary, the electrostatic image developing toner used in the development step is1 itemAn image forming method comprising the toner for developing an electrostatic image described in 1.
[0026]
  4. In an image forming apparatus for forming an image through each means of charging, image exposure, development, thermal fixing, and means with blade cleaning as necessary, the electrostatic image developing toner used in the developing means is1 itemAn image forming apparatus comprising the toner for developing an electrostatic image described in 1.
[0027]
  As a result of examining the above problems in various ways and proceeding with research,Contains release agentWhen producing agglomerated latex particles to produce colored particles, a mixture of latex particles having a peak in the range of 50 to 200 nm and latex particles having a peak in the range of 300 to 3000 nm, peaks in the range of 300 to 3000 nm. Latex particles havingContains release agentUsing latex that accounts for 0.5 to 30% by mass of the total latex particles provides a wide temperature range in which no fixing offset occurs, no initial image fogging, and high-quality images continue even when a large amount of printing is performed. As a result, the present invention has been found and obtained.
[0028]
  In the present invention, the toner has colored particles containing at least a resin, a colorant, and a release agent.Contains release agentMade by agglomeration of latex particles. The latex used for agglomeration is a mixture of particles having peaks in the range of at least 50-200 nm and 300-3000 nm,Contains release agentLatex having a peak in the range of 300 to 3000 nm (hereinafter also referred to as a large particle size latex) in which 0.5 to 30% by mass of the total latex particles is a latex having a peak in the range of 50 to 200 nm (hereinafter referred to as “latex”) (Also referred to as small particle size latex) is characterized by containing a large amount of a release agent having a large particle size and taking in a colorant well.
[0029]
Comparing the particle size of the release agent in the cross section between the colored particles produced by agglomerating the large particle latex and the colored particles produced by aggregating the small particle latex, the colored particles produced by aggregating the large particle latex The particle size of the release agent is larger and the amount is larger.
[0030]
Measurement of the domain diameter and amount of the release agent particles dispersed in the colored particles was performed by magnifying and magnifying the obtained image with a transmission electron microscope to obtain a magnification of 2000 times. It can be calculated by analyzing with Nippon Avionics Co., Ltd.).
[0031]
Colored particles (toner) made by agglomerating large particle size latex containing a large amount of release agent with a large domain diameter are easy to elute in a wide temperature range from the colored particles during thermal fixing. It is considered that the temperature range where no fixing offset occurs is widened.
[0032]
Further, the colorant is more adhered to the particle surface of the large particle size latex than the small particle size latex. When the colorant adheres to the latex particle surface, the colorant remaining free (free) in the solution used for aggregation decreases.
[0033]
The reason why a large amount of the colorant adheres to the particle surface of the large particle size latex is not clear, but when the particle size of the latex and the colorant particle size in the dispersed state are compared, the small particle size latex (50 to 200 nm) and the colorant ( The particle size difference between the large particle size latex (300 to 3000 nm) and the colorant is so large that the colorant is likely to adhere to the particle surface of the large particle size latex. .
[0034]
The difference in adhesion of the colorant to the latex particle surface depends on the concentration of the solution obtained by removing the colored particles using a centrifuge from the solution used in the aggregation of the large particle size latex and the solution used in the aggregation of the small particle size latex. It can be evaluated by comparing the concentration of the solution excluding the colored particles using a centrifuge. Obviously, the concentration of the solution used in the aggregation of the small particle size latex is high by visual judgment. It can be seen that there is not much colorant attached. When a free (free) colorant is present in the solution used for aggregation, the color particles adhere to the surface of the colored particles in a free (free) state and are dried as they are.
[0035]
The free colorant adhering to the surface of the colored particles adheres to the non-image area during printing and generates image fogging, or adheres to the carrier surface of the developer and shortens the life of the developer.
[0036]
In addition, the crushing strength of the colored particles is higher in the colored particles prepared by mixing a suitable amount of the small particle size latex and the large particle size latex than the colored particles prepared by the small particle size latex or the large particle size latex alone.
[0037]
When the crushing strength is high, the generation of ultrafine particles can be prevented because the colored particles are not crushed by mixing with the carrier in the developing unit or by screw conveyance during toner recycling. Ultrafine particles adhere to the carrier and cause deterioration of the developer.
[0038]
However, colored particles prepared by mixing appropriate amounts of small particle size latex and large particle size latex do not generate ultra fine particles, so the developer does not deteriorate and high quality (no fogging) High density images can be obtained continuously.
[0039]
  The mixing amount of large particle size latex isContains release agentA balance of 0.5 to 30% by mass based on the total latex is suitable for achieving the above object.
[0040]
  First, the latex according to the present invention will be described.
  The latex for preparing the colored particles comprises at least a small particle size latex and a large particle size latex. or,Contains release agentAlthough it is characterized by 0.5-30 mass% of all the latex being a large particle size latex, it is more preferable in it being 2-20 mass%.
[0041]
  The method for preparing the latex is not particularly limited, and a small particle size latex and a large particle size latex are prepared separately, and the amount of the large particle size latex isContains release agentA mixture of a small particle size latex and a large particle size latex may be prepared so as to be 0.5 to 30% by mass of the total latex, or it may be prepared by a single polymerization. In order to obtain, a method of separately preparing and mixing a small particle size latex and a large particle size latex is preferable.
[0042]
In addition, latex particles having different particle diameters can be obtained by controlling conditions at the time of latex production (for example, the amount of an anionic active agent, stirring speed, addition time, etc.).
[0043]
The particle size peak and particle size distribution of latex can be measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.). .
[0044]
In order to favorably attach the colorant particles to the latex particle surface, the colorant particles are preferably finely dispersed in the solution to a mass average particle size of about 30 to 200 nm.
[0045]
The average particle size of the colorant particles in the colorant dispersion is determined by using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.). Can be measured.
[0046]
Next, the toner of the present invention and the manufacturing method thereof will be described.
<Emulsion polymerization method>
The toner of the present invention is characterized in that it is prepared by salting out / fusing latex particles (resin particles) obtained by emulsion polymerization in an aqueous medium. Examples of this method include the methods described in JP-A Nos. 5-265252, 6-329947, and 9-15904.
[0047]
That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, etc., or particles composed of resin and colorant, particularly in water using an emulsifier After that, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer itself is heated and fused at a temperature higher than the glass transition temperature to gradually grow the particle size while forming fused particles. When the target particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated in a fluidized 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.
[0048]
In the method for producing a toner of the present invention, the composite resin fine particles and the colorant particles formed through the step of polymerizing the polymerizable monomer after dissolving the release agent in the polymerizable monomer are salted out / fused. A method of wearing is preferably used. When the release agent is dissolved in the polymerizable monomer, it may be dissolved by dissolving the release agent or may be dissolved by melting.
[0049]
In addition, as a method for producing the toner of the present invention, a step of salting out / fusing composite resin fine particles and colorant particles obtained by a multistage polymerization method is preferably used. Here, the multistage polymerization method will be described below.
[0050]
<Method for producing toner obtained by multistage polymerization method>
When the multistage polymerization method is used, the toner production method of the present invention is preferably composed of the following steps.
[0051]
1: A step of polymerizing composite resin particles by a multistage polymerization method
2: Salting out / fusion process for obtaining colored particles by salting out / fusion of composite resin particles and colorant particles
3: Filtration / washing step of filtering out the colored particles from the dispersed system of the colored particles and removing the surfactant from the colored particles
4: Drying step of drying washed colored particles
5: A step of preparing a toner by adding an external additive to the dried colored particles
Consists of
[0052]
Hereinafter, each step will be described in detail.
[Multistage polymerization process]
The multi-stage polymerization process is a polymerization method performed to expand the molecular weight distribution of resin particles so as to obtain a toner in which fixing offset is prevented. That is, in order to form phases having different molecular weight distribution in one resin particle, the polymerization reaction is performed in multiple stages, and the obtained resin particle has a molecular weight gradient from the center of the particle toward the surface layer. It is intended to be formed. For example, a method of forming a low molecular weight surface layer by first obtaining a high molecular weight resin particle dispersion and then newly adding a polymerizable monomer and a chain transfer agent is employed. By setting the surface layer of the arrival letter to a low molecular weight, the resin particles can be firmly fused with each other, and colored particles having high crushing strength can be prepared.
[0053]
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. Hereinafter, the two-stage polymerization method and the three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described.
[0054]
(Two-stage polymerization method)
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion formed from a high molecular weight resin containing a release agent and an outer peripheral portion formed from a low molecular weight resin.
[0055]
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, this system is polymerized (first stage polymerization) to prepare a dispersion of high molecular weight resin particles (center part) containing a release agent.
[0056]
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). This is a method of forming a coating layer (peripheral part) made of a low molecular weight resin (monomer polymer) on the surface of the resin particles.
[0057]
(Three-stage polymerization method)
The three-stage polymerization method is composed of resin particles (center portion) formed from a high molecular weight resin, an intermediate layer (outer peripheral portion) formed from a release agent and a low molecular weight resin, and an outer layer formed from a low molecular weight resin. This is a method for producing composite resin particles. Here, when the molecular weight of the resin of the outer layer is set to a low molecular weight, it is preferable that the composite resins are firmly fused when the colored particles are formed.
[0058]
This method will be specifically described. First, a dispersion of resin particles composed of a high molecular weight resin obtained by a polymerization process (first stage polymerization) according to a conventional method is used as an aqueous medium (for example, a surfactant). In addition, a monomer solution obtained by dissolving a release agent in a monomer is dispersed in oil droplets in the aqueous medium, and then this system is polymerized (second-stage polymerization). As a result, an intermediate layer (peripheral part) made of a low molecular weight resin (monomer polymer) containing a release agent is formed on the surface of the resin particles (center part), and composite resin particles (center part) A dispersion having a high molecular weight resin and a low molecular weight resin on the outer periphery is prepared.
[0059]
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) forms an outer layer made of a low molecular weight resin (monomer polymer) on the surface of the composite resin particles. In the above method, it is preferable that the release agent is finely and uniformly dispersed by incorporating the release agent into the intermediate layer.
[0060]
The aqueous medium used in the present invention refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. 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.
[0061]
As a suitable polymerization method for forming resin particles or an intermediate layer containing a release agent, a release agent is used as a monomer in an aqueous medium in which a surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. The monomer solution dissolved in 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 cause radical polymerization in the oil droplets. The method (hereinafter referred to as “mini-emulsion method” in the present invention) is preferred.
[0062]
According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, there is little detachment of the release agent dissolved in the oil phase, and it is sufficient in the formed resin particles or coating layer. A sufficient amount of release agent can be introduced.
[0063]
Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirring device “CLEARMIX” (manufactured by M Technique Co., Ltd.) equipped with a rotor that rotates at high speed. , Ultrasonic dispersers, mechanical homogenizers, Manton Gorin and pressure homogenizers. The dispersed particle diameter is preferably 10 to 1000 nm, more preferably 50 to 1000 nm, and particularly preferably 30 to 300 nm.
[0064]
(Particle size of latex particles)
The particle size peak of the latex particles (resin particles, composite resin particles) according to the present invention is obtained when the monomer mixture is added to the initiator solution in which the polymerization initiator is dissolved in the surfactant solution to produce the resin particles. Amount of monomer mixture and dropping rate, system temperature, stirring conditions, etc., amount of monomer mixture and dropping rate, system temperature, stirring conditions when producing intermediate layer and outer layer on the surface of resin particles It can control by controlling etc. For example, when increasing the particle size peak, it is possible to obtain a particle size peak by polymerizing a large particle size latex with slow stirring and increasing the amount of monomers forming the intermediate layer and the outer layer. When making it small, it can obtain by making small latex polymerize by making stirring high-speed and reducing the quantity of the monomer which forms an intermediate | middle layer and an outer layer.
[0065]
The particle diameters of the resin particles and composite resin particles obtained in this polymerization step are determined by electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.) and “Microtrack UPA-150” (manufactured by Nikkiso Co., Ltd.). Can be measured. The peak of the particle diameter can be obtained from the measured value.
[0066]
The glass transition temperature (Tg) of the composite resin particles is preferably in the range of 48 to 74 ° C, more preferably 5 to 64 ° C.
[0067]
The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C.
The toner of the present invention is obtained by salting out / fuseting composite resin particles and colorant particles to form colored particles, and adding an external additive to the colored particles. This will be described below.
[0068]
[Salting out / fusion process]
This salting-out / fusion step is carried out by salting out / bonding the composite resin particles and the colorant particles obtained in the multi-stage polymerization step (to cause salting-out and fusion at the same time) to form an irregular shape ( This is a step of obtaining non-spherical colored particles.
[0069]
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 preferable 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. .
[0070]
In this salting-out / fusion step, internal additive particles such as charge control agents (fine particles having a number average primary particle size of about 10 to 1000 nm) may be salted out / fused together with the composite resin particles and the colorant particles. Good. The colorant particles may be surface-modified, and conventionally known ones can be used as the surface modifier.
[0071]
[Aging process]
The aging step is a step subsequent to the salting-out / fusion step, and after the resin particles are fused, the temperature is kept near the melting point of the release agent, preferably the melting point ± 20 ° C., and stirring is continued at a constant strength. This is a step of phase-separating the release agent.
[0072]
Moreover, in this invention, it is preferable that the total value of the bivalent (trivalent) metal element used for a flocculant and the monovalent metal element added as a coagulation terminator mentioned later is 350-35000 ppm. The measurement of the residual amount of metal ions in the colored particles is carried out using a fluorescent X-ray analyzer “System 3270 type” (manufactured by Rigaku Denki Kogyo Co., Ltd.) and the metal species of the metal salt used as a flocculant (for example, calcium chloride) It can be determined by measuring the intensity of the fluorescent X-ray emitted from the derived calcium or the like. As a specific measurement method, a plurality of colored particles having a known content ratio of the flocculant metal salt are prepared, each colored particle 5g is pelletized, the content ratio (mass ppm) of the flocculant metal salt, The relationship (calibration curve) with the fluorescent X-ray intensity (peak intensity) from the metal species is measured. Next, the colored particles (sample) whose content of the flocculant metal salt is to be measured are similarly pelletized, and the fluorescent X-ray intensity from the metal species of the flocculant metal salt is measured. The residual amount of ions ”can be determined.
[0073]
[Filtering and washing process]
In this filtration / washing step, a filtration treatment for filtering the colored particles from the colored particle dispersion obtained in the above step, and a surfactant or salt from the filtered colored particles (cake-like aggregate). A cleaning process for removing deposits such as a depositing agent is performed. 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.
[0074]
[Drying process]
This step is a step for drying the washed colored particles.
[0075]
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.
[0076]
The water content of the dried colored particles is preferably 5% by mass or less, more preferably 2% by mass or less.
[0077]
In addition, when the dried colored particles 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.
[0078]
The toner of the present invention forms composite resin particles in the absence of a colorant, adds a dispersion of the colorant particles to the dispersion of the composite resin particles, and saltes out the composite resin particles and the colorant particles. It is preferably prepared by fusing.
[0079]
Thus, the polymerization reaction for obtaining the composite resin particles is not inhibited by preparing the composite resin particles in a system in which no colorant is present.
[0080]
Further, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the resulting colored particles, and the heat fixing step of the image forming method using the toner In this case, no off-flavor is generated.
[0081]
Next, each component used in the toner manufacturing process will be described in detail.
(Polymerizable monomer)
As a polymerizable monomer for producing the resin 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.
[0082]
(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.
[0083]
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.
[0084]
Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.
[0085]
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.
[0086]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.
[0087]
Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.
[0088]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.
[0089]
Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.
[0090]
(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.
[0091]
(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).
[0092]
Examples of the α, β-ethylenically unsaturated compound (a) having a —COO 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.
[0093]
-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.
[0094]
(4) Monomers having basic polar groups
As the monomer having a basic polar group, (i) a (meth) acrylic acid ester of an aliphatic alcohol having 1 to 12, preferably 2 to 8, particularly preferably 2, an amine group or a quaternary ammonium group. , (Ii) (meth) acrylic acid amide or (meth) acrylic acid amide mono- or disubstituted optionally with an alkyl group having 1 to 18 carbon atoms on N, (iii) a heterocyclic group having N as a ring member 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.
[0095]
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.
[0096]
(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.
[0097]
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.
[0098]
Examples of (iv) N, N-diallyl-alkylamine include N, N-diallylmethylammonium chloride and N, N-diallylethylammonium chloride.
[0099]
(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.
[0100]
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, polymerization can be performed 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).
[0101]
(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.
[0102]
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).
[0103]
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.
[0104]
In the present invention, these surfactants are mainly used as an emulsifier during emulsion polymerization, but may be used for other processes or for other purposes.
[0105]
(Flocculant)
The flocculant used in the present invention is preferably selected from metal salts.
[0106]
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.
[0107]
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.
[0108]
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.
[0109]
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.
[0110]
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.
[0111]
(Coloring agent)
The colored particles according to the present invention are obtained by salting out / fusion-bonding the composite resin particles and the colorant particles.
[0112]
Examples of the colorant used in the present invention (colorant particles used for salting out / fusion with the composite resin particles) 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.
[0113]
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.
[0114]
These inorganic pigments can be used alone or in combination as required. The pigment is added in an amount of 2 to 20% by mass, preferably 3 to 15% by mass, based on the polymer.
[0115]
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 colorant from the viewpoint of imparting predetermined magnetic properties.
[0116]
Conventionally known organic pigments and dyes can also be used. Specific organic pigments and dyes are exemplified below.
[0117]
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.
[0118]
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.
[0119]
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.
[0120]
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.
[0121]
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 colored particles, Preferably 3-15 mass% is selected.
[0122]
The colorant (colorant particles) used in 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.
[0123]
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.
[0124]
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.
[0125]
The surface-modified colorant particles are collected by filtration, washed with the same solvent and filtered, and then dried.
[0126]
(Release agent)
The colored particles according to the present invention are preferably those 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 colorant in which the release agent is finely dispersed can be obtained. .
[0127]
The release agent used in the present invention is preferably low molecular weight polypropylene (number average molecular weight = 1500-9000), low molecular weight polyethylene, or the like, more preferably an ester compound represented by the following formula.
[0128]
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.
[0129]
Next, the example of a typical compound is shown below.
[0130]
[Chemical 1]

[0131]
[Chemical formula 2]

[0132]
The addition amount of the said compound is 1-30 mass% with respect to the whole colored particle, Preferably it is 2-20 mass%, More preferably, it is 3-15 mass%.
[0133]
The colored particles according to the present invention are preferably prepared by encapsulating the release agent in resin particles by the mini-emulsion polymerization method, and salting out and fusing together with the colored particles.
[0134]
(Charge control agent)
In addition to the colorant and the release agent, the colored particles can be added with materials that can impart various functions as a material for colored particles. Specific examples include charge control agents. These components can be added simultaneously with the resin particles and the colorant particles in the salting-out / fusion stage described above, and can be added by various methods such as a method of inclusion in the colored particles and a method of adding to the resin particles themselves.
[0135]
As the charge control agent, various known ones that can be dispersed in water can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.
[0136]
(External additive)
In the toner of the present invention, the colored particles may be used as they are, but it is more preferable to use a so-called external additive added to the colored particles 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.
[0137]
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.
[0138]
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., and HVK-2150 manufactured by Hoechst Co., Ltd. , H-200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5 manufactured by Cabot Corporation.
[0139]
Specific examples of the titanium fine particles include, for example, commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B, MT-500BS, and MT-600 manufactured by Teika Co., Ltd. , MT-600SS, JA-1, commercial products manufactured by Fuji Titanium Co., Ltd. TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T, commercial products IT-S manufactured by Idemitsu Kosan Co., Ltd. IT-OA, IT-OB, IT-OC and the like.
[0140]
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.
[0141]
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.
[0142]
Examples of the lubricant that can be used as an external additive include metal salts of higher fatty acids. Specific examples of such higher fatty acid metal salts include zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate, and other stearic acid metal salts; zinc oleate, manganese oleate, iron oleate, olein Oleic acid metal salts such as acid copper and magnesium oleate; palmitate metal salts such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; linoleic acid metal salts such as zinc linoleate and calcium linoleate; ricinol Examples include ricinoleic acid metal salts such as zinc acid and calcium ricinoleate.
[0143]
The addition amount of the external additive is preferably about 0.1 to 5% by mass with respect to the colored particles.
[0144]
<External additive addition process>
This step is a step of adding an external additive to the dried colored particles.
[0145]
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.
[0146]
(Toner particles)
The particle size of the toner of the present invention is preferably 3 to 10 μm, more preferably 3 to 8 μm, in terms of number average particle size. 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 composition of the polymer in the method for producing colored particles.
[0147]
Since the particles of the external additive are very fine particles, the particle size of the toner obtained by adding the external additive to the colored particles and the colored particles are almost the same as the measurement results.
[0148]
When the number average particle size is 3 to 10 μm, in the fixing process, toner particles with high adhesion force that fly and adhere to the heating member to generate fixing offset are reduced, and transfer efficiency is increased, resulting in halftone. The image quality of the fine lines, dots, etc. is improved.
[0149]
The number average particle size of the toner is measured using “Coulter Counter TA-II”, “Coulter Multisizer” (manufactured by Coulter Co., Ltd.), laser diffraction particle size measuring device “SLAD1100” (manufactured by Shimadzu Corporation), etc. can do.
[0150]
In the present invention, 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 to calculate the particle size distribution and average particle size.
[0151]
(Developer)
The toner of the present invention can be used as a one-component developer or a two-component developer.
[0152]
Specific examples of the one-component developer include 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. it can.
[0153]
The toner 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. Particles are preferred. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
[0154]
The volume average particle diameter of the carrier can be measured by a laser diffraction particle size distribution measuring apparatus “Heros” (manufactured by Sympathic Co., Ltd.) equipped with a wet disperser.
[0155]
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 for coating is not particularly limited, and known resins can be used. Specifically, olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, or fluorine-containing resins can be used. Polymer based resins and the like are used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. Specifically, styrene-acrylic resins, polyester resins, fluorine resins, phenol resins, etc. Can be used.
[0156]
(Image forming method)
Next, an image forming method and an image forming apparatus using the toner of the present invention will be described.
[0157]
FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus showing an example of an image forming method using the toner of the present invention.
[0158]
The image forming apparatus shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B (not shown), an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. It is configured.
[0159]
The upper part of the image reading unit A is provided with automatic document feeding means for automatically conveying the document. The document placed on the document placing table 111 is separated and conveyed by the document conveying roller 112 to the reading position 113a. The image is read. The document after the document reading is completed is discharged onto the document discharge tray 114 by the document transport roller 112.
[0160]
On the other hand, the image of the original when placed on the platen glass 113 is read at a speed v of the first mirror unit 115 including the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by moving the second mirror unit 116 composed of the two mirrors and the third mirror in the same direction at the speed v / 2.
[0161]
The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 117. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.
[0162]
In the image forming unit C, as an image forming unit, a drum-shaped photosensitive member (hereinafter also referred to as a photosensitive drum) 121 that is an image carrier, a charger 122 that is a charging unit, and a developing unit that is a developing unit are provided on the outer periphery thereof. A device 123, a transfer device 124 as transfer means, a separator 125 as separation means, a cleaning device (blade cleaning) 126, and a PCL (precharge lamp) 127 are arranged in the order of operation. The photoconductor 121 is formed by coating a photoconductive compound on a drum base. For example, an organic photoconductor (OPC) is preferably used, and is driven to rotate in the clockwise direction shown in the drawing.
[0163]
After the rotating photosensitive member 121 is uniformly charged by the charger 122, the exposure optical system 130 performs image exposure based on the image signal called from the memory of the image processing unit B. The exposure optical system 130 as writing means uses a laser diode (not shown) as a light source, passes through a rotating polygon mirror 131, an fθ lens (no symbol), and a cylindrical lens (no symbol), and the optical path is bent by a reflection mirror 132 to perform main scanning. Thus, image exposure is performed on the photoconductor 121 at the position Ao, and a latent image is formed by rotation (sub-scanning) of the photoconductor 121. In one example of the present embodiment, the character portion is exposed to form a latent image.
[0164]
The latent image on the photoconductor 121 is reversely developed by the developing device 123, and a visible toner image is formed on the surface of the photoconductor 121. In the transfer paper transport section D, paper feed units 141 (A), 141 (B), and 141 (C) are provided below the image forming unit as transfer paper storage means for storing transfer paper P of different sizes. Further, a manual paper feed unit 142 for manually feeding paper is provided on the side, and the transfer paper P selected from any of these is fed along the transport path 140 by the guide roller 143 and fed. The transfer paper P is temporarily stopped by a pair of registration rollers 144 that corrects the inclination and bias of the transfer paper to be transferred, and then fed again, and is guided to the transport path 140, the pre-transfer roller 143a, and the transfer entrance guide plate 146. The toner image on the photoconductor 121 is transferred to the transfer paper P by the transfer device 124 at the transfer position Bo, and then the charge is removed by the separator 125, so that the transfer paper P is separated from the surface of the photoconductor 121. And it is conveyed to a fixing device 150 by a conveying device 145.
[0165]
The fixing device 150 has a fixing roller 151 and a pressure roller 152. By passing the transfer paper P between the fixing roller 151 and the pressure roller 152, the toner is fused by heating and pressing. . After the toner image has been fixed, the transfer paper P is discharged onto a paper discharge tray 164.
[0166]
【Example】
The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.
[0167]
<< Preparation of colored particles 1 >>
(Preparation of large particle size latex (1HML))
<1: Preparation of resin particles (first stage polymerization)>
An anionic surfactant A (C) was added to a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet._TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeA surfactant solution (aqueous medium) in which 2.5 g of Na) was dissolved in 3040 g of ion-exchanged water was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0168]
To this surfactant solution, an initiator solution in which 10.0 g of a polymerization initiator (potassium persulfate: KPS) was dissolved in 400 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., 528 g of styrene, and n-butyl acrylate. A monomer mixture composed of 204 g, methacrylic acid 68.0 g, and n-octyl-3-mercaptopropionic acid ester 24.4 g was dropped into the liquid stirred at a low speed over 1 hour. This system was heated and stirred at 75 ° C. for 2 hours to carry out polymerization (first stage polymerization) to prepare latex (a dispersion of resin particles made of high molecular weight resin). This is referred to as “large particle size latex (1H)”.
[0169]
<2: Formation of intermediate layer (second stage polymerization)>
In a flask equipped with a stirrer, 95.0 g of styrene, 36.0 g of n-butyl acrylate, 9.0 g of methacrylic acid, 0.59 g of n-octyl-3-mercaptopropionic acid ester, 77 g of the exemplified compound 19) was added as a release agent, and heated and dissolved at 90 ° C. to prepare “Monomer Solution 1”.
[0170]
Next, a surfactant solution prepared by dissolving 0.8 g of the anionic surfactant A in 1560 ml of ion-exchanged water is heated to 98 ° C., and a dispersion of resin particles “large particles” is added to the surfactant solution. After adding 28 g of “diameter latex (1H)” in terms of solid content, the above-prepared “monomer solution 1” was added by a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. An emulsified liquid containing emulsified particles (oil droplets) that were mixed and dispersed for a time and having a uniform dispersed particle size was prepared.
[0171]
Next, an initiator solution prepared by dissolving 5.0 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water and 750 ml of ion-exchanged water are added to this emulsion, and this system is heated and stirred at 98 ° C. for 12 hours. To obtain a latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin is covered with an intermediate molecular weight resin). This is referred to as “large particle size latex (1HM)”.
[0172]
<3: Formation of outer layer (third stage polymerization)>
An initiator solution prepared by dissolving 6.8 g of a polymerization initiator (KPS) in 265 ml of ion-exchanged water is added to the above-prepared “large particle size latex (1HM)”, and 249 g of styrene, n -A monomer mixed solution consisting of 88.2 g of butyl acrylate, 19.4 g of methacrylic acid, and 7.45 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, and then cooled to 28 ° C., and latex (a central portion made of a high molecular weight resin and an intermediate layer made of an intermediate molecular weight resin) And an outer layer made of a low molecular weight resin). This latex is referred to as “large particle size latex (1HML)”.
[0173]
The particle diameter of “Large Particle Size Latex (1HML)” was measured with “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.) and the peak was determined. The peak was 700 nm in terms of mass average.
[0174]
(Preparation of small particle size latex (1HML))
<1: Preparation of resin particles (first stage polymerization)>
An anionic surfactant A (C) was added to a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet._TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeA surfactant solution (aqueous medium) in which 5.0 g of Na) was dissolved in 3040 g of ion-exchanged water was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0175]
To this surfactant solution, an initiator solution in which 10.0 g of a polymerization initiator (potassium persulfate: KPS) was dissolved in 400 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., 528 g of styrene, and n-butyl acrylate. A monomer mixture composed of 204 g, methacrylic acid 68.0 g, and n-octyl-3-mercaptopropionic acid ester 24.4 g was dropped into the liquid stirred at high speed over 1 hour. The system was heated and stirred at 75 ° C. for 2 hours to perform polymerization (first stage polymerization) to prepare latex (a dispersion of resin particles made of high molecular weight resin). This is referred to as “small particle size latex (1H)”.
[0176]
<2: Formation of intermediate layer (second stage polymerization)>
In a flask equipped with a stirrer, 95.0 g of styrene, 36.0 g of n-butyl acrylate, 9.0 g of methacrylic acid, 0.59 g of n-octyl-3-mercaptopropionic acid ester, 77 g of the exemplified compound 19) was added as a release agent, and heated and dissolved at 90 ° C. to prepare “Monomer Solution 1”.
[0177]
Next, a surfactant solution in which 1.5 g of the anionic surfactant A was dissolved in 1560 ml of ion exchange water was heated to 98 ° C., and a dispersion of resin particles “small particles” was added to the surfactant solution. After adding 28 g of “diameter latex (1H)” in terms of solid content, the above-prepared “monomer solution 1” was added by a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. An emulsified liquid containing emulsified particles (oil droplets) that were mixed and dispersed for a time and having a uniform dispersed particle size was prepared.
[0178]
Next, an initiator solution prepared by dissolving 5.0 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water and 750 ml of ion-exchanged water are added to this emulsion, and this system is heated and stirred at 98 ° C. for 12 hours. To obtain a latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin is covered with an intermediate molecular weight resin). This is referred to as “small particle size latex (1HM)”.
[0179]
<3: Formation of outer layer (third stage polymerization)>
An initiator solution prepared by dissolving 6.8 g of a polymerization initiator (KPS) in 265 ml of ion-exchanged water is added to the above-prepared “small particle size latex (1HM)”, and 249 g of styrene, n -A monomer mixed solution consisting of 88.2 g of butyl acrylate, 19.4 g of methacrylic acid, and 7.45 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, and then cooled to 28 ° C., and latex (a central portion made of a high molecular weight resin and an intermediate layer made of an intermediate molecular weight resin) And an outer layer made of a low molecular weight resin, and a dispersion of composite resin particles) containing the exemplified compound 19) as a release agent in the intermediate layer was obtained. This latex is referred to as “small particle size latex (1HML)”.
[0180]
The particle size of “small particle latex (1HML)” was measured with “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.) and the peak was determined. The peak was 120 nm in terms of mass average.
[0181]
(Preparation of latex (2L))
An initiator solution prepared by dissolving 14.8 g of a polymerization initiator (KPS) in 400 ml of ion-exchanged water was added to a flask equipped with a stirrer, and under a temperature condition of 80 ° C., 600 g of styrene, 190 g of n-butyl acrylate, A monomer mixed solution consisting of 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 was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. to obtain a latex (a dispersion of resin particles made of a low molecular weight resin). This latex is referred to as “latex (2 L)”.
[0182]
The resin particles constituting this “latex (2L)” have a molecular weight peak at 11,000, and the particle size of the resin particles is measured by “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.). As a result, the mass average particle diameter was 120 nm.
[0183]
(Preparation of colorant dispersion (1))
Anionic surfactant (sodium dodecyl sulfate) 59.0 g was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring this solution, 420.0 g of carbon black was gradually added, and then disperser “Clearmix” (M A “colorant dispersion (1)” in which a colorant was dispersed was prepared by performing dispersion treatment using Technique Co., Ltd.
[0184]
(Aggregation / fusion process)
84 g (solid content conversion) of the prepared “large particle size latex (1HML)”, “336 g (solid content conversion)” of the “small particle size latex (1HML)”, 900 g of ion-exchanged water, and the above-prepared “colorant dispersion” 200 g of “Liquid (1)” was placed in a reaction vessel (four-necked flask) equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device and stirred. After adjusting the temperature in the container to 30 ° C., a 5 mol / L sodium hydroxide aqueous solution was added to this solution to adjust the pH to 9.0.
[0185]
Next, an aqueous solution in which 12.1 g of magnesium chloride hexahydrate was dissolved in 1000 ml of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, heating was started, and the aqueous solution was heated to 90 ° C. over 60 minutes to start particle growth. In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II”. When the volume average particle size reached 5.0 μm, 40.2 g of sodium chloride as a stopper was added to 1000 ml of ion-exchanged water. The aqueous solution dissolved in was added to stop particle growth. Further, as the aging treatment, the fusion was continued by heating and stirring at a liquid temperature of 98 ° C. for 2 hours. Then, it cooled to 30 degreeC on the conditions of 8 degreeC / min.
[0186]
(Shelling process)
According to the above, 96 g of the prepared “latex (2 L)” is added to the aggregated / fused particles, and heating and stirring are continued for 3 hours to obtain “large particle size latex (1 HML)” and “small” “Latex (2L)” was shelled on the surface of aggregated particles of “particle size latex (1HML)”. Next, 40.2 g of sodium chloride was added and cooled to 30 ° C. under a temperature drop condition of 8 ° C./min. Then, hydrochloric acid was added to adjust the pH to 2.0, and stirring was stopped.
[0187]
The fused particles thus shelled were filtered, repeatedly washed with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to prepare “colored particles 1”.
[0188]
The “colored particle 1” thus prepared has a volume average particle size of 6.4 μm, the resin constituting the “colored particle 1” has a mass average molecular weight of 55,000, and the glass transition temperature (Tg) of the resin. Was 57 ° C., and the softening point of the resin was 125 ° C.
<< Preparation of colored particles 2 >>
In “Preparation of Colored Particles 1”, the mixing amount of “Large Particle Size Latex (1HML)” and “Small Particle Size Latex (1HML)” is changed from 84 g (in terms of solid content) of “Large Particle Size Latex (1HML)”. “Colored particle 2” is the same as “Preparation of colored particle 1” except that 336 g (in terms of solid content) is changed to 378 g (in terms of solid content). Was prepared.
<< Preparation of colored particles 3 >>
In “Preparation of Colored Particles 1”, the mixing amount of “Large Particle Size Latex (1HML)” and “Small Particle Size Latex (1HML)” is changed from 84 g (in terms of solid content) of “Large Particle Size Latex (1HML)”. Same as “Preparation of colored particles 1” except that 336 g (solid content conversion) was changed to 411.6 g (solid content conversion) to 8.4 g (solid content conversion). “Colored particles 3” were prepared.
<< Preparation of colored particles 4 >>
In “Preparation of Colored Particles 1”, the mixing amount of “Large Particle Size Latex (1HML)” and “Small Particle Size Latex (1HML)” is changed from 84 g (in terms of solid content) of “Large Particle Size Latex (1HML)”. Same as “Preparation of colored particles 1” except that 336 g (solid content conversion) was changed to 2.17.9 g (solid content conversion) to 2.1 g (solid content conversion). “Colored particles 4” were prepared.
<< Preparation of colored particles 5 >>
In “Preparation of Colored Particles 1”, the mixing amount of “Large Particle Size Latex (1HML)” and “Small Particle Size Latex (1HML)” is changed from 84 g (in terms of solid content) of “Large Particle Size Latex (1HML)”. “Colored particle 5” was the same as “Preparation of colored particle 1” except that 336 g (solid content converted) was changed to 252 g (solid content converted) to “168 g (solid content converted)”. Was prepared.
<< Preparation of colored particles 6 >>
In “Preparation of Colored Particles 1”, the mixing amount of “Large Particle Size Latex (1HML)” and “Small Particle Size Latex (1HML)” is changed from 84 g (in terms of solid content) of “Large Particle Size Latex (1HML)”. “Colored particle 6” is the same as “Preparation of colored particle 1” except that “small particle size latex (1HML)” 336 g (solid content converted) is changed to 420 g (solid content converted) to 0 g (solid content converted). Was prepared.
<< Preparation of colored particles 7 >>
In “Preparation of Colored Particles 1”, the mixing amount of “Large Particle Size Latex (1HML)” and “Small Particle Size Latex (1HML)” is changed from 84 g (in terms of solid content) of “Large Particle Size Latex (1HML)”. “Colored particle 7” was prepared in the same manner as “Preparation of colored particle 1” except that 336 g of “small particle size latex (1HML)” was changed to 0 g (in terms of solid content). Was prepared.
[0189]
<< Preparation of toner and developer >>
To the “colored particles 1 to 7” prepared above, 1.0% by mass of hydrophobic silica (number average primary particle size: 12 nm, hydrophobization degree: 68) and hydrophobic titanium oxide (number average primary particle size: “Toner 1-7” was prepared by adding 1.2% by mass of 20 nm, hydrophobization degree: 63) and mixing with a Henschel mixer.
[0190]
Next, a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin was mixed with each of the toners prepared above to prepare “Developers 1 to 7” each having a toner concentration of 6%.
[0191]
The domain size of the average release agent in the colored particles was calculated by analysis using the “Spica”, and the particle size of the colored particles was measured using the “Coulter Multisizer”.
[0192]
  Table 1 shows the addition of colored particles, the peak of latex particles,Contains release agentThe amount of the large particle size latex in all the latexes, the size of the release agent domain size, and the color particle size are shown.
[0193]
[Table 1]

[0194]
"Evaluation results"
<Fixing offset resistance evaluation>
A digital copier “7065” (manufactured by Konica Corporation) was modified, and the fixing offset of “Toners 1 to 7” prepared above and toner contamination of the fixing roller were evaluated under the following conditions.
[0195]
The fixing device was remodeled so that the cleaning mechanism and the like that are in contact with the fixing roller were all removed, and nothing was in contact with the fixing roller. The copying environment is set to normal temperature and humidity (25 ° C, 55% RH), and the surface temperature of the fixing roller for fixing (measured at the center of the roller) is in the range of 150 to 180 ° C in 10 ° C increments. In each surface temperature, A4 size plain paper having a solid black belt image with a width of 5 mm is transported and fixed by vertical feed at a position orthogonal to the transport direction, and then a solid with a width of 5 mm is disposed at a position orthogonal to the transport direction. A4 size plain paper having a black belt-like image and a halftone image with a width of 20 mm is conveyed in the horizontal direction. For each of the obtained samples, image stain (fixing offset) due to fixing offset and toner contamination on the surface of the fixing roller are removed. Visual observation was performed, and the fixing offset resistance was evaluated according to the following criteria.
[0196]
A: Neither occurrence of fixing offset nor toner contamination on the surface of the fixing roller is observed.
○: Almost no occurrence of fixing offset and toner contamination on the surface of the fixing roller is observed.
Δ: No occurrence of fixing offset is observed, but toner contamination on the surface of the fixing roller is observed
X: Fixation offset and toner contamination on the surface of the fixing roller are observed
XX: The occurrence of clear fixing offset is recognized, and toner contamination on the surface of the fixing roller is remarkable.
In the evaluation rank, it was determined that 判定 and ○ were practically acceptable.
[0197]
<Image evaluation>
A digital copier “Konica 7065” (manufactured by Konica Corporation) that recycles toner is remodeled and an evaluation machine in which the fixing roller surface temperature of the fixing device is set to 170 ° C. is used. ), Using the “Toners 1-7” and “Developers 1-7” prepared above, an A4 plate image with a pixel rate of 7% was printed on plain paper (64 g / m 2).²) And 100,000 sheets were printed continuously.
[0198]
The initial image fogging was evaluated with a magnifying glass for the non-image area of the 10th print.
[0199]
Image fogging due to fusing offset contamination of the fixing roller was evaluated based on the number of image fogging. Further, the image fog generated during the continuous printing was evaluated by the number of sheets where the image fog occurred, and the image density was evaluated by the density of the print after the printing of 100,000 sheets.
[0200]
still. The fog was visually evaluated, and the image density was measured with a “Macbeth densitometer” (manufactured by Macbeth Co., Ltd.).
[0201]
Table 2 shows the state of occurrence of fixing offset when the surface temperature of the fixing roller is changed, the initial image fogging, the number of image fogging due to fusing roller contamination, the number of image fogging in continuous printing, and the image density after printing 100,000 sheets. Indicates.
[0202]
[Table 2]

[0203]
As is apparent from Table 2, the “toners 1 to 4” of the present invention have a wider fixing temperature range in which no fixing offset occurs, less initial image fogging, and continuousness than the “toners 5 to 7” of the comparative example. Even if printing is performed, image fogging due to contamination of the fixing roller does not occur, fogging due to developer deterioration and density reduction do not occur, and the durability is excellent.
[0204]
【The invention's effect】
As demonstrated in the examples, the toner of the present invention, the method for producing the toner, the image forming method and the image forming apparatus using the toner have a wide temperature range in which no fixing offset occurs, no initial image fogging, and a large amount Even if printing is performed, the image has an excellent effect of continuously obtaining a high-quality image (image fogging, image density reduction).
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus showing an example of an image forming method using toner of the present invention.
[Explanation of symbols]
121 photoconductor
122 Charger
123 Developer
124 Transfer device
125 separator
126 Cleaning device
127 PCL (precharge lamp)
130 Exposure optical system
151 Fixing device
P transfer paper

Claims (4)

In the electrostatic image developing toner having colored particles containing at least a resin, a colorant and a release agent, the colored particles are prepared by agglomeration of latex particles containing a release agent , and the latex particles are at least A mixture of particles each having a peak in the range of 50 to 200 nm and 300 to 3000 nm, and the latex particle having a peak in the range of 300 to 3000 nm is 0.5 to 30% by mass of the total latex particles containing a release agent. A toner for developing an electrostatic charge image. A method for producing a toner for developing an electrostatic image having colored particles containing at least a resin, a colorant and a release agent, wherein the colored particles are produced by agglomeration of latex particles containing a release agent. Are prepared separately for those having a peak in the range of 50 to 200 nm and those having a peak in the range of 300 to 3000 nm, and the latex particles having a peak in the range of 300 to 3000 nm contain all the release agent. A method for producing a toner for developing an electrostatic image, wherein the toner is blended so as to be 0.5 to 30% by mass of latex particles. The electrostatic charge image developing toner used in the developing step in an image forming method for forming an image through each step of charging, image exposure, development, and heat fixing, and a step of adding blade cleaning as necessary. An image forming method, which is a toner for developing an electrostatic image. The electrostatic charge image developing toner used in the developing means in an image forming apparatus that forms an image through each means of charging, image exposure, development, thermal fixing, and means to which blade cleaning is added if necessary. An image forming apparatus, which is an electrostatic charge image developing toner.

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