JP4254072B2 - Toner for developing electrostatic image and image forming method - Google Patents

Description

【０２３７】
【化２】

【０２３８】
また、本発明では結晶性物質として結晶性ポリエステルも用いることができるものであるが、結晶性ポリエステルとしては、脂肪族ジオールと、脂肪族ジカルボン酸（酸無水物および酸塩化物を含む）とを反応させて得られるポリエステルが好ましい。
【０２３９】
結晶性ポリエステルを得るために使用されるジオールとしては、エチレングリコール、ジエチレングリコール、トリエチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，４−ブタンジオール、１，４−ブテンジオール、ネオペンチルグリコール、１，５−ペンタングリコール、１，６−ヘキサンジオール、１，４−シクロヘキサンジオール、１，４−シクロヘキサンジメタノール、ジプロピレングリコール、ポリエチレングリコール、ポリプロピレングリコール、ポリテトラメチレングリコール、ビスフェノールＡ、ビスフェノールＺ、水素添加ビスフェノールＡ等を挙げることができる。
【０２４０】
結晶性ポリエステルを得るために使用されるジカルボン酸としては、シュウ酸、マロン酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スペリン酸、アゼライン酸、セバシン酸、マレイン酸、フマール酸、シトラコ酸、イタコン酸、グルタコ酸、ｎ−ドデシルコハク酸、ｎ−ドデセニルコハク酸、イソドデシルコハク酸、イソドデセニルコハク酸、ｎ−オクチルコハク酸、ｎ−オクテニルコハク酸、これらの酸無水物あるいは酸塩化物を挙げることができる。
【０２４１】
特に好ましい結晶性ポリエステルとしては、１，４−シクロヘキサンジメタノールとアジピン酸とを反応して得られるポリエステル、１，６−ヘキサンジオールとセバシン酸とを反応して得られるポリエステル、エチレングリコールとコハク酸とを反応して得られるポリエステル、エチレングリコールとセバシン酸とを反応して得られるポリエステル、１，４−ブタンジオールとコハク酸とを反応して得られるポリエステルを挙げることができ、これらのうち、１，４−シクロヘキサンジメタノールとアジピン酸とを反応して得られるポリエステルが最も好ましい。
【０２４２】
上記化合物の添加量は、トナー全体に対し１〜３０質量％、好ましくは２〜２０質量％、更に好ましくは３〜１５質量％である。
【０２４３】
（現像剤）
本発明のトナーは、一成分現像剤でも二成分現像剤として用いてもよく、一成分現像剤として用いる場合は、非磁性一成分現像剤、あるいはトナー中に０．１〜０．５μｍ程度の磁性粒子を含有させた磁性一成分現像剤が挙げられいずれも使用できる。
【０２４４】
また、キャリアと混合して二成分現像剤として用いることもでき、この場合は、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いることが出来る。特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５〜１００μｍ、より好ましくは２５〜８０μｍのものがよい。
【０２４５】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０２４６】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン−アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレン−アクリル系樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０２４７】
次に本発明のトナーを用いる画像形成方法に用いる画像形成装置について説明する。
【０２４８】
図４は本発明の画像形成装置の一例を示す断面構成図である。４は被帯電体である感光体ドラムであり、アルミニウム製のドラム基体の外周面に感光体層である有機光導電体（ＯＰＣ）を形成してなるもので矢印方向に所定の速度で回転する。
【０２４９】
図４において、図示しない原稿読み取り装置にて読み取った情報に基づき、半導体レーザ光源１から露光光が発せられる。これをポリゴンミラー２により、図４の紙面と垂直方向に振り分け、画像の歪みを補正するｆθレンズ３を介して、感光体面上に照射され静電潜像を作る。感光体ドラム４は、予め帯電器５により一様帯電され、像露光のタイミングにあわせて時計方向に回転を開始している。
【０２５０】
感光体ドラム面上の静電潜像は、現像器６により現像され、形成された現像像はタイミングを合わせて搬送されてきた転写紙８に転写器７の作用により転写される。更に感光体ドラム４と転写紙８は分離器（分離極）９により分離されるが、現像像は転写紙８に転写担持されて、定着器１０へと導かれ定着される。
【０２５１】
感光体面に残留した未転写のトナー等は、クリーニングブレード方式のクリーニング器１１にて清掃され、帯電前露光（ＰＣＬ）１２にて残留電荷を除き、次の画像形成のため再び帯電器５により、一様帯電される。
【０２５２】
トナーリサイクルを行うための方式としては特に限定されるものでは無いが、例えば、クリーニング部で回収されたトナーを搬送コンベアあるいは搬送スクリューによって補給用トナーホッパー、現像器あるいは補給用トナーと中間室によって混合して現像器へ供給する方法等をあげることができる。好ましくは現像器へ直接戻す方式あるいは中間室にて補給用トナーとリサイクルトナーを混合して供給する方式をあげることができる。
【０２５３】
次に図５において、トナーのリサイクル部材斜視構成図の一例を挙げる。この方式は現像器へリサイクルトナーを直接戻す方式である。
【０２５４】
クリーニングブレード１３で回収された未転写トナーはトナークリーニング器１１内の搬送スクリュウによってトナーリサイクルパイプ１４に集められ、更にこのリサイクルパイプの受け口１５から現像器６に戻され、再び現像剤として使用される。
【０２５５】
図５は又、本発明の画像形成装置に着脱自在のプロセスカートリッジの斜視図でもある。この図５では斜視構造を判りやすくするため感光体ユニットと現像剤ユニットを分離した図面になっているが、これを全部一体化したユニットとして着脱自在に画像形成装置に搭載できる。この場合、感光体、現像器、クリーニング器及びリサイクル部材が一体となりプロセスカートリッジを構成している。
【０２５６】
又、上記画像形成装置は、感光体ドラムと、帯電器、現像器、クリーニング器あるいはリサイクル部材等の少なくとも一つを含むプロセスカートリッジを搭載する形態にすることもできる。
【０２５７】
次に、転写紙は代表的には普通紙であるが、現像後の未定着像を転写可能なものなら、特に限定されず、ＯＨＰ用のＰＥＴベース等も無論含まれる。
【０２５８】
又、クリーニングブレード１３は、厚さ１〜３０ｍｍ程度のゴム状弾性体を用い、材質としてはウレタンゴムが最も良く用いられる。これは感光体に圧接して用いられるため熱を伝え易く、本発明においては解除機構を設け、画像形成動作を行っていない時には感光体から離しておくのが望ましい。
【０２５９】
本発明は、電子写真法による画像形成装置、特にコンピュータ等からのデジタル画像データで変調した変調ビームにより感光体上に静電潜像を形成する装置に使用することもできる。図６は、本発明のトナーに適用されるデジタル画像形成装置を示す概略図である。
【０２６０】
近年、感光体上に静電潜像を形成し、この潜像を現像して可視画像を得る電子写真等の分野において、画質の改善、変換、編集等が容易で高品質の画像形成が可能なデジタル方式を採用した画像形成方法の研究開発が盛んになされている。
【０２６１】
この画像形成方法及び装置に採用されるコンピュータまたは複写原稿からのデジタル画像信号により光変調する走査光学系として、レーザ光学系に音響光学変調器を介在させ、当該音響光学変調器により光変調する装置、半導体レーザを用い、レーザ強度を直接変調する装置があり、これらの走査光学系から一様に帯電した感光体上にスポット露光してドット状の画像を形成する。
【０２６２】
前述の走査光学系から照射されるビームは、裾が左右に広がった正規分布状に近似した丸状や楕円状の輝度分布となり、例えばレーザビームの場合、通常、感光体上で主走査方向あるいは副走査方向の一方あるいは両者が２０〜１００μｍという極めて狭い丸状あるいは楕円状である。
【０２６３】
本発明のトナーは、トナー像が形成された画像形成支持体を、定着装置を構成する加熱ローラーと加圧ローラーとの間に通過させて定着する工程を含む画像形成方法に好適に使用されるものであって、線速が２３０〜９００ｍｍ／ｓｅｃという定着速度の範囲内において使用することのできるものである。
【０２６４】
図７は、本発明のトナーを用いた画像形成方法において使用する定着装置の一例を示す断面図であり、図７に示す定着装置１０は、加熱ローラー７１と、これに当接する加圧ローラー７２とを備えている。なお、図７において、Ｔは転写紙（画像形成支持体）上に形成されたトナー像である。
【０２６５】
加熱ローラー７１は、フッ素樹脂または弾性体からなる被覆層８２が芯金８１の表面に形成されてなり、線状ヒーターよりなる加熱部材７５を内包している。
芯金８１は、金属から構成され、その内径は１０〜７０ｍｍとされる。芯金８１を構成する金属としては特に限定されるものではないが、例えば鉄、アルミニウム、銅等の金属あるいはこれらの合金を挙げることができる。
【０２６６】
芯金８１の肉厚は０．１〜１５ｍｍとされ、省エネルギーの要請（薄肉化）と、強度（構成材料に依存）とのバランスを考慮して決定される。例えば、０．５７ｍｍの鉄よりなる芯金と同等の強度を、アルミニウムよりなる芯金で保持するためには、その肉厚を０．８ｍｍとする必要がある。
【０２６７】
被覆層８２を構成するフッ素樹脂としては、ＰＴＦＥ（ポリテトラフルオロエチレン）およびＰＦＡ（テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合体）などを例示することができる。
【０２６８】
フッ素樹脂からなる被覆層８２の厚みは１０〜５００μｍとされ、好ましくは２０〜４００μｍとされる。
【０２６９】
フッ素樹脂からなる被覆層８２の厚みが１０μｍ未満であると、被覆層としての機能を十分に発揮することができず、定着装置としての耐久性を確保することができない。一方、５００μｍを超える被覆層の表面には紙粉によるキズがつきやすく、当該キズ部にトナーなどが付着し、これに起因する画像汚れを発生する問題がある。
【０２７０】
また、被覆層８２を構成する弾性体としては、ＬＴＶ、ＲＴＶ、ＨＴＶなどの耐熱性の良好なシリコーンゴムおよびシリコーンスポンジゴムなどを用いることが好ましい。
【０２７１】
被覆層８２を構成する弾性体のアスカーＣ硬度は、８０°未満とされ、好ましくは６０°未満とされる。
【０２７２】
また、弾性体からなる被覆層８２の厚みは０．１〜３０ｍｍとされ、好ましくは０．１〜２０ｍｍとされる。
【０２７３】
被覆層８２を構成する弾性体のアスカーＣ硬度が８０°を超える場合、および当該被覆層８２の厚みが０．１ｍｍ未満である場合には、定着のニップを大きくすることができず、ソフト定着の効果（例えば、平滑化された界面のトナー層による色再現性の向上効果）を発揮することができない。
【０２７４】
加熱部材７５としては、ハロゲンヒーターを好適に使用することができる。加圧ローラー７２は、弾性体からなる被覆層８４が芯金８３の表面に形成されてなる。被覆層８４を構成する弾性体としては特に限定されるものではなく、ウレタンゴム、シリコーンゴムなどの各種軟質ゴムおよびスポンジゴムを挙げることができ、被覆層８４を構成するものとして例示したシリコーンゴムおよびシリコーンスポンジゴムを用いることが好ましい。
【０２７５】
被覆層８４を構成する弾性体のアスカーＣ硬度は、８０°未満とされ、好ましくは７０°未満、更に好ましくは６０°未満とされる。
【０２７６】
また、被覆層８４の厚みは０．１〜３０ｍｍとされ、好ましくは０．１〜２０ｍｍとされる。
【０２７７】
被覆層８４を構成する弾性体のアスカーＣ硬度が８０°を超える場合、および被覆層８４の厚みが０．１ｍｍ未満である場合には、定着のニップを大きくすることができず、ソフト定着の効果を発揮することができない。
【０２７８】
芯金８３を構成する材料としては特に限定されるものではないが、アルミニウム、鉄、銅などの金属またはそれらの合金を挙げることができる。
【０２７９】
加熱ローラー１０と加圧ローラー７２との当接荷重（総荷重）としては、通常４０〜３５０Ｎとされ、好ましくは５０〜３００Ｎ、さらに好ましくは５０〜２５０Ｎとされる。この当接荷重は、加熱ローラー１０の強度（芯金８１の肉厚）を考慮して規定され、例えば０．３ｍｍの鉄よりなる芯金を有する加熱ローラーにあっては、２５０Ｎ以下とすることが好ましい。
【０２８０】
また、耐オフセット性および定着性の観点から、ニップ幅としては４〜１０ｍｍであることが好ましく、当該ニップの面圧は０．６×１０⁵Ｐａ〜１．５×１０⁵Ｐａであることが好ましい。
【０２８１】
図７に示した定着装置による定着条件の一例を示せば、定着温度（加熱ローラー１０の表面温度）が１５０〜２１０℃とされ、定着線速が２３０〜９００ｍｍ／ｓｅｃとされる。
【０２８２】
【実施例】
以下、実施例を挙げて本発明を詳細に説明するが、本発明の態様はこれに限定されない。なお、文中「部」とは「質量部」を表す。
【０２８３】
トナー用樹脂粒子の製造例
〔ラテックス１ＨＭＬ〕
（１）核粒子の調製（第一段重合）：
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
（１０１） Ｃ₁₀Ｈ₂₁（ＯＣＨ₂ＣＨ₂）₂ＯＳＯ₃Ｎａ
７．０８ｇをイオン交換水３０１０ｇに溶解させた界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの攪拌速度で攪拌しながら、フラスコ内の温度を８０℃に昇温させた。
【０２８４】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）９．２ｇをイオン交換水２００ｇに溶解させた開始剤溶液を添加し、温度を７５℃とした後、スチレン７０．１ｇ、ｎ−ブチルアクリレート１９．９ｇ、メタクリル酸１０．９ｇからなる単量体混合液を１時間かけて滴下し、この系を７５℃にて２時間にわたり加熱、攪拌することにより重合（第一段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（１Ｈ）」とする。
【０２８５】
（２）中間層の形成（第二段重合）；
攪拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．２ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル５．６ｇからなる単量体混合液に、結晶性物質として、上記式（１９）で表される化合物（以下、「例示化合物（１９）」という。）９８．０ｇを添加し、９０℃に加温し溶解させて単量体溶液を調製した。
【０２８６】
一方、アニオン系界面活性剤（上記式（１０１））１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を９８℃に加熱し、この界面活性剤溶液に、核粒子の分散液である前記ラテックス（１Ｈ）を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム・テクニック（株）製）により、前記例示化合物（１９）の単量体溶液を８時間混合分散させ、乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０２８７】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を９８℃にて１２時間にわたり加熱攪拌することにより重合（第二段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを「ラテックス（１ＨＭ）」とする。
【０２８８】
前記ラテックス（１ＨＭ）を乾燥し、走査型電子顕微鏡で観察したところ、ラテックスに取り囲まれなかった例示化合物（１９）を主成分とする粒子（４００〜１０００ｎｍ）が観察された。
【０２８９】
（３）外層の形成（第三段重合）：
上記の様にして得られたラテックス（１ＨＭ）に、重合開始剤（ＫＰＳ）７．４ｇをイオン交換水２００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン３００ｇ、ｎ−ブチルアクリレート９５ｇ、メタクリル酸１５．３ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル１０．４ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱攪拌することにより重合（第三段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層に例示化合物（１９）が含有されている複合樹脂粒子の分散液を得た。このラテックスを「ラテックス（１ＨＭＬ）」とする。
【０２９０】
このラテックス（１ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１３，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１２２ｎｍであった。
【０２９１】
〔ラテックス２ＨＭＬ〕
界面活性剤（１０１）に代えて、アニオン系界面活性剤（ドデシルベンゼンスルフォン酸ナトリウム：ＳＤＳ）７．０８ｇを使用したこと以外は、調製例１と同様にして、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複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（２ＨＭＬ）」とする。
【０２９２】
このラテックス（２ＨＭＬ）を構成する複合樹脂粒子は、１３８，０００、８０，０００および１２，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１１０ｎｍであった。
【０２９３】
〔着色粒子１〜１３及び比較用着色粒子１〜４の製造〕
アニオン系界面活性剤（１０１）５９．０ｇをイオン交換水１６００ｍｌに攪拌溶解し、この溶液を攪拌しながら、カーボンブラック「リーガル３３０」（キャボット社製）４２０．０ｇを徐々に添加し、次いで「クレアミックス」（エム・テクニック（株）製）を用いて分散処理することにより、着色剤粒子の分散液（以下「着色剤分散液１」という。）を調製した。この着色剤分散液における着色剤粒子の粒子径を、電気泳動光散乱光度計「ＥＬＳ−８００」（大塚電子社製）を用いて測定したところ、重量平均粒径で８９ｎｍであった。
【０２９４】
ラテックス１ＨＭＬ４２０．７ｇ（固形分換算）と、イオン交換水９００ｇと、着色剤分散液１ １６６ｇ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℃に調製した後、この溶液に５Ｎの水酸化ナトリウム水溶液を加えてｐＨを８〜１０．０に調製した。
【０２９５】
次いで、塩化マグネシウム・６水和物１２．１ｇをイオン交換水１０００ｍｌに溶解した水溶液を、攪拌下、３０℃にて１０分間かけて添加した。３分間放置した後に昇温を開始し、この系を６〜６０分間かけて９０℃まで昇温し、会合粒子の生成を行った。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、個数平均粒径が４〜７μｍになった時点で、塩化ナトリウム８０．４ｇをイオン交換水１０００ｍｌに溶解した水溶液を添加して粒子成長を停止させ、更に熟成処理として液温度８５〜９８℃にて２〜１２時間にわたり加熱攪拌することにより、粒子の融着及び結晶性物質の相分離を継続させた（熟成工程）。
【０２９６】
その後、３０℃まで冷却し、塩酸を添加してｐＨを２．０に調整し、攪拌を停止した。生成した会合粒子を濾過し、４５℃のイオン交換水で繰り返し洗浄を行い、その後、４０℃の温風で乾燥することにより、着色粒子を得た。
【０２９７】
前記凝集工程のｐＨ、熟成処理工程の温度、熟成時間、攪拌強度を制御することにより、結晶性物質、着色剤分散状態、形状および形状係数の変動係数を制御し、更に、液中分級により、トナー粒径および粒度分布の変動係数を任意に調整して、表１〜表３に示す分散状態、形状特性および粒度分布特性、及び海島構造の特性を有する着色粒子からなる着色粒子１〜１３および比較用着色粒子１〜４を得た。
【０２９８】
【表１】

【０２９９】
【表２】

【０３００】
【表３】

【０３０１】
以上の様にして得られた着色粒子１〜１３及び比較用着色粒子１〜４の各々に、疎水性シリカ０．８質量部、疎水性酸化チタン１．０質量部を添加し、１０ｌのヘンシェルミキサーの回転翼の周速を３０ｍ／ｓに設定し２５分間混合した。なお、これらの着色粒子について、外部添加剤の添加によってその形状や粒径は変化しないものである。
【０３０２】
キャリアの製造
フェライト芯材の製造
ＭｎＯを１８ｍｏｌ％、ＭｇＯを４ｍｏｌ％、Ｆｅ₂Ｏ₃を７８ｍｏｌ％を湿式ボールミルで２時間粉砕、混合し乾燥させた後に、９００℃で２時間保持することにより仮焼成し、これをボールミルで３時間粉砕しスラリー化した。分散剤およびバインダーを添加し、スプレードライヤーにより造粒、乾燥し、その後１２００℃ｍ３時間本焼成を行い、抵抗値４．３×１０⁸Ω・ｃｍのフェライト芯材粒子を得た。
【０３０３】
被覆用樹脂の製造
先ず、界面活性剤として炭素数１２のアルキル基を有するベンゼンスルホン酸ナトリウムを用いた水溶液媒体中の濃度を０．３質量％とした乳化重合法により、シクロヘキシルメタクリレート／メチルメタクリレート（共重合比５／５）の共重合体を合成し、体積平均一次粒径０．１μｍｍ、重量平均分子量（Ｍｗ）２００，０００、数平均分子量（Ｍｎ）９１，０００、Ｍｗ／Ｍｎ＝２．２、軟化点温度（Ｔｓｐ）２３０℃およびガラス転移温度（Ｔｇ）１１０℃の樹脂微粒子を得た。なお、前記樹脂微粒子は、乳化状態において、水と共沸し、残存モノマー量を５１０ｐｐｍとした。
【０３０４】
次に、フェライト芯材粒子１００質量部と前記樹脂微粒子２質量部とを攪拌羽根付き高速攪拌混合機に投入し、１２０℃で３０分間攪拌混合して機械的衝撃力の作用を利用して体積平均粒径６１μｍの樹脂被覆キャリアを得た。
【０３０５】
現像剤の製造
外部添加剤が添加された着色粒子１〜１３及び比較用着色粒子１〜４の各々とキャリアとを混合し、トナー濃度が６質量％の現像剤を調製し、実施例１〜１３、及び比較例１〜４とした。
【０３０６】
感光体Ｐ１の製造
長さ３８０ｍｍ、直径６０ｍｍの円筒状導電性支持体上に下記の塗布液を塗布し、感光体Ｐ１を作製した。
〈下引き層〉
チタンキレート化合物（ＴＣ−７５０ 松本製薬社製） ３０ｇ
シランカップリング剤（ＫＢＭ−５０３ 信越化学社製） １７ｇ
２−プロパノール １５０ｍｌ
上記塗布液を用いて円筒状導電性支持体上に、膜厚０．５μｍとなるよう塗布した。
【０３０７】
〈電荷発生層〉
Ｙ型チタニルフタロシアニン（Ｃｕ−Ｋα特性Ｘ線回折スペクトル測定で、ブラッグ角２θ（±０．２°）の２７．２°に最大ピークを有するチタニルフタロシアニン） ６０ｇ
シリコーン変性ブチラール樹脂（Ｘ−４０−１２１１Ｍ：信越化学社製）７００ｇ
２−ブタノン ２０００ｍｌ
を混合し、サンドミルを用いて１０時間分散し、電荷発生層塗布液を調製した。この塗布液を前記下引き層の上に浸漬塗布法で塗布し、膜厚０．２μｍの電荷発生層を形成した。
【０３０８】
〈電荷輸送層〉
電荷輸送物質 Ｎ−（４−メチルフェニル）−Ｎ−｛４−（β−フェニルスチリル）フェニル｝−ｐ−トルイジン ２２５ｇ
ポリカーボネート（粘度平均分子量３０，０００） ３００ｇ
酸化防止剤（例示化合物１−３） ６ｇ
ジクロロメタン ２０００ｍｌ
を混合し、溶解して電荷輸送層塗布液を調製した。この塗布液を前記電荷発生層の上に浸漬塗布法で塗布し、乾燥膜厚２０μｍの電荷輸送層を形成した。
【０３０９】
〈保護層〉
メチルトリメトキシシラン １５０ｇ
ジメチルジメトキシシラン ３０ｇ
反応性電荷輸送性化合物（例示化合物Ｂ−１） １５ｇ
ポリフッ化ビニリデン粒子（体積平均粒径０．２μｍ） １０ｇ
酸化防止剤（例示化合物２−１） ０．７５ｇ
２−プロパノール ７５ｇ
３％酢酸 ５ｇ
を混合し、樹脂層用の塗布液を調製した。この塗布液を前記電荷輸送層の上に円形量規制型塗布装置により厚さ２μｍの樹脂層を形成し、１２０℃、１時間の加熱硬化を行い、シロキサン樹脂層を形成し、感光体Ｐ１を作製した。
【０３１０】
【化３】

【０３１１】
評価機として、図６に記載の画像形成プロセスを有するデジタル複写機（コロナ帯電、レーザ露光、反転現像、静電転写、爪分離、クリーニングブレードを有する）に、感光体（Ｐ１）及び各現像剤を搭載し評価した。上記デジタル複写機は以下の条件に設定し評価を行った。
【０３１２】
帯電条件
帯電器；スコロトロン帯電器、初期帯電電位を−７５０Ｖ
露光条件
露光部電位を−５０Ｖにする露光量に設定。
現像条件
ＤＣバイアス；−５５０Ｖ
転写極；コロナ帯電方式
【０３１３】
また、定着装置としては、芯金として鉄を使用し、表面を厚さ２５μｍのＰＦＡ（テトラフルオロエチレン−パーフルオロアルキルビニルエーテル共重合体）で被覆された表面粗さＲａが０．８μｍの加熱ローラーを使用し、加圧ローラーとして鉄の芯金を使用し、ＨＴＶシリコーンゴムの上に厚み１２０μｍのＰＦＡチューブを被覆した表面粗さＲａが０．８μｍの加圧ローラーを用いた。なお、ニップ幅は３．８ｍｍであり、線速は４２０ｍｍ／ｓｅｃである。
【０３１４】
なお、定着装置のクリーニング機構及びシリコンオイル供給機構は装着していない。定着の温度は加熱ローラーの表面温度で制御し、１６５℃の設定温度とした。
【０３１５】
複写条件は、低温低湿環境（１０℃、２０％ＲＨ）にて連続５０万コピー行い、コピー画像のノンビジュアルオフセット性、高速定着時の巻き付き、クリーニング性、感光体のフィルミング発生、感光体の寿命、ハーフトーンの均一性及び文字つぶれの発生状況について評価を行った。
【０３１６】
＜ノンビジュアルオフセット性＞
１０ｍｍ×５０ｍｍ、厚さ５ｍｍのフェルトパッドを５０ｇ／ｃｍ²（５×１０^-5Ｐａ）の荷重で当接させ、１０，０００枚印字後の汚れを観察した。
評価基準
：フェルトパッドに汚れの発生が無い。
：フェルトパッドにごく軽微な汚れが発生（実用上問題なし）。
×：フェルトパッド画像上に汚れが発生（実用上問題有り）。
【０３１７】
＜高速定着時の巻き付き＞
熱ローラの温度設定を１６５℃としたままラインスピードの設定を４２０ｍｍ／ｓｅｃから８４０ｍｍ／ｓｅｃに変化させ、２０，０００枚印字後にベタ画像のコピーを行い、巻き付き性と定着率の評価を行った。
評価基準
：定着分離不良による紙詰まり発生がなく、定着分離爪痕も観察されない。
：定着分離不良による紙詰まり発生はないが、定着分離爪痕が若干認められた（実用上問題なし）。
×：定着分離不良による紙詰まり発生（実用上問題有り）。
なお、定着率の測定は、Ａ４サイズの普通紙（秤量６５ｇ／ｍ²）を使用した。
【０３１８】
＜定着ローラ寿命＞
定着ローラ上についた傷による画像汚れが発生した枚数で評価した。
【０３１９】
＜クリーニング性能＞
画像白地部にクリーニング装置から感光体上にトナーがすりぬけて、画像汚れとして判別された枚数で評価した。下記◎及び○を合格とした。
評価基準
：５０万枚まで発生なし。
：４０万〜５０万枚で発生。
×：４０万枚未満で発生。
【０３２０】
＜製本時の汚れ＞
６４ｇ／ｍ２の普通紙に両面コピーを行い、一冊あたり１００枚の冊子としたのち、２０回手めくりした時の白地部の汚れを観察した。
ランクＡ：画像上に汚れの発生がない。
ランクＢ：画像上にごく軽微な汚れが確認されたが、実用上全く問題ないレベルのもの。
ランクＣ：画像上に軽微な汚れが確認されたが、実用上問題ないレベルのもの。
ランクＤ：画像上に汚れがあり、実用に適さない。
評価ランクＡ、Ｂ、Ｃを合格、Ｄを不合格とした。
【０３２１】
＜感光体フィルミング＞
前述の連続５０万コピー後の感光体表面を目視観察により、フィルミングの有無を判定した。
【０３２２】
＜感光体の寿命＞
露光量を最大にしたときのカブリ濃度（転写紙に対する非画像部の相対濃度）が０．０１を超えた時点の枚数で評価した。カブリ濃度は反射濃度測定機ＰＤＡ−６５（コニカ（株）製）で測定した。
【０３２３】
＜ハーフトーンの均一性＞
感光体フィルミング等の転写性変動に伴うハーフトーン画像の均一性を評価した。評価基準は以下のとおりである。
ランクＡ：ムラのない均一な画像。
ランクＢ：スジ状の薄いムラが存在するが実用上問題なし。
ランクＣ：スジ状の薄いムラが数本存在するが実用上問題なし。
ランクＤ：スジ状のはっきりしたムラが数本以上存在し、実用上問題有り。
【０３２４】
＜文字つぶれ＞
３ポイント、５ポイントの文字画像を形成し、下記の評価基準で評価した。
◎：３ポイント、５ポイントとも明瞭であり、容易に判読可能で実用上問題なし。
○：３ポイントは、一部判読不能な文字が発生しているが、５ポイントは明瞭で容易に判読可能で実用上問題なし。
×：３ポイントは、殆どの文字が判読不能であり、５ポイントも、一部あるいは全部が判読不能な状態で実用上問題有り。
以上の評価項目についての結果を表４に示す。
【０３２５】
【表４】

【０３２６】
前記表４の結果からも明らかな様に、本発明の静電荷像現像用トナーでは、ノンビジュアルオフセットの発生抑制等が達成され、定着装置を３０万枚以上の長期にわたり、部材交換する必要なく連続使用可能であることが確認された。また、感光体の寿命も大幅に延長させることを可能にする結果が得られ、比較試料として用いられた従来技術の静電荷像現像用トナーよりも遙かに優れた性能を有する者であることが確認された。
【０３２７】
【発明の効果】
本発明の静電荷像現像用トナーによれば、トナー中の結晶性物質の定着工程時における効果的な滲出を可能としたことにより、ノンビジュアルオフセットの発生を抑制可能とし、低速機から高速機に至るまで定着装置よりオイル塗布機構を排除することを可能ならしめ、定着ローラー寿命を大幅に延長するとともに製本時における紙への汚れ付着防止を可能にした。また、感光体フィルミング等の発生を抑えることを可能とした結果、感光体寿命の延長も可能なものとし、鮮鋭性に優れた画像を長期にわたって提供することを可能とした。
【０３２８】
【図面の簡単な説明】
【図１】本発明の海島構造を有するトナー粒子を説明する模式図及び本発明のトナー粒子中の島間の最近接壁間距離を矢印（←→）で示した模式図（島Ｂは省略）である。
【図２】本発明の海島構造を有するトナー粒子をボロノイ多角形によって分割した模式図である。
【図３】本発明の海島構造を有するトナー粒子に含有される着色剤粒子を得るために使用する攪拌装置である。
【図４】本発明に適用される画像形成装置の一例を示す断面構成図。
【図５】トナーのリサイクル部材斜視構成図。
【図６】本発明に適用されるデジタル画像形成装置の概略図である。
【図７】本発明に適用される定着装置の概略断面図。
【図８】角なしまたは角のあるトナーを説明する模式図である。
【符号の説明】
１ 半導体レーザ光源
２ ポリゴンミラー
３ ｆθレンズ
４ 感光体ドラム
５ 帯電器
６ 現像器
７ 転写器
８ 転写紙
９ 分離器
１０ 定着器
１１ クリーニング器
１２ 帯電前露光
１３ クリーニングブレード
１４ トナーリサイクルパイプ
１５ リサイクルパイプの受け口
７１ 加熱ローラ
７２ 加圧ローラ
７５ 加熱部材
８１ 加熱ローラの芯金
８２ 加熱ローラの被覆層
１０１ スクリーン
１０２ ロータ
１０３ 加圧真空アタッチメント
１０４ 予備分散液出口
１０５ 分散液出口
１０６ 温度センサー
１０７ 冷却ジャケット
１０８ 冷却コイル
１１１ 分散容器
１１２ 攪拌装置
１１３ 攪拌シャフト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner for developing an electrostatic image used in a copying machine, a printer, and the like, and an image forming method using the toner for developing an electrostatic image, and more specifically, has a feature in the structure of the toner particles. It is about things.
[0002]
[Prior art]
In recent years, in an image forming method using an electrophotographic method, digital image forming is becoming mainstream due to progress in digital technology. The digital image forming method is based on visualizing a small dot image of one pixel such as 1200 dpi (number of dots per inch), and there is a high image quality technology that faithfully reproduces these small dot images. There is a demand, and from the viewpoint of such high image quality, the toner particle size is being reduced.
[0003]
As a means for achieving toner particle size reduction, flow rate distribution and uniform shape, polymerized toner obtained by suspension polymerization method or emulsion polymerization method is attracting attention. Japanese Patent Application No. 11-304004, etc. Describes that the shape, roundness, and particle size distribution of a toner obtained by a polymerization method can be controlled.
[0004]
As a method for fixing a toner image formed on an image forming support such as paper, heat for fixing the image forming support on which the toner image is formed by passing between a heating roller and a pressure roller. The roll fixing method is widely used. However, the hot roll fixing method has a drawback that an offset phenomenon in which the molten toner adheres to the heating roller is generated, and image smearing is likely to occur.
[0005]
Therefore, as a means for preventing the occurrence of the offset phenomenon, it is known to apply silicone oil to the heating roller of the fixing device to give the heating roller releasability. This method is advantageous in that the type of toner is not limited, but it is unsuitable for business documents because it becomes difficult to write with a writing instrument such as a ballpoint pen because silicone oil adheres to the transfer paper. In the market, copy documents are immediately used as business documents, and writing into documents is very common, and the method of applying silicone oil is becoming unable to meet the demands of the times.
[0006]
In response to such a demand, a technique for imparting releasability to the toner itself by adding a release agent such as wax in the toner is employed. A sea island structure in which polypropylene as a mold release agent is dispersed in a polymer is formed, and the maximum diameter in the major axis direction of the island portion of the polypropylene and the average distance between the island and the island are specified. No. 161338 discloses a toner release agent component having a sea-island structure in which the particle size of the release agent component before heat fixing is specified and the sea-island structure disappears after heat fixing.
[0007]
However, even if the release agent is introduced into the toner in this way, it is still necessary to install a fixing roller cleaning mechanism. The reason for this is that although toner with a release agent does not generate an offset in image formation to the extent that printing is performed in units of several sheets, such image formation gradually undergoes image formation of 10,000 to 20,000 sheets. In addition, toner accumulates on the fixing roller to generate an offset called a so-called non-visual offset. From the viewpoint of preventing the occurrence of non-visual offset, it is necessary to replace the cleaning member of the fixing device every tens of thousands of sheets.
[0008]
Also, the processing capability of the image forming apparatus has been improved, and high-speed machines having an output of 50 sheets or more per minute have appeared. In such a high-speed machine, the release agent in the toner is applied to the toner surface in the fixing process. Since the fixing process is completed before it sufficiently exudes, the release agent contained in the toner cannot sufficiently function, so not only non-visual offset is likely to occur, but also at a small number of processing stages. This will cause an offset.
[0009]
Further, the toner disclosed in the above-mentioned document is based on a pulverization method, and the release agent is oriented in the produced toner through a kneading process. When the release agent is oriented in the toner, since the exudation of the release agent component on the toner surface in the fixing process follows the orientation direction, isotropic exudation in all directions of the toner is not performed, and further fixing. It becomes difficult to exert the effect of the release agent between the roller and the transfer paper. Thus, there is no pulverized toner that can withstand use in a high-speed machine.
[0010]
From the viewpoint of high image quality, the toner particle size has been reduced, and as disclosed in JP-A-8-41468, a technique for improving the release agent compound and increasing the amount added to the toner has been studied. However, when a large amount of release agent is added, the release agent is released from the toner particles, and the released release agent deteriorates the developer, lowers the toner fluidity, and generates photoconductor filming. Have a problem.
[0011]
Japanese Patent Application Laid-Open No. 5-88409 discloses a polymerized toner having a toner particle structure specified and having a large spherical release agent island in the binder resin. However, the release to individual toner particles is disclosed. It has been found that some of the toner particles do not have islands of the release agent because the variation in the additive amount cannot be eliminated. In addition, since the shape of the release agent in the toner particles is spherical, the contact area between the release agent and the resin is reduced, and the chargeability of the toner is reduced due to the release of the release agent from the toner particles. This causes toner degradation that is inviting.
[0012]
Further, in the above document, it takes time until the release agent oozes out on the toner surface in the fixing process from a structure in which one or two islands of release agent having a large diameter exist near the center of the toner particle. For this reason, there is a problem that a sufficient release agent layer cannot be formed between the fixing roller and the toner, and until now, the technology that has been able to withstand the use in high-speed machines has been delivered to the market. There was no.
[0013]
[Problems to be solved by the invention]
The present invention has been made based on the above circumstances. That is,
A first object of the present invention is to provide a toner for developing an electrostatic charge image that is excellent in non-visual offset property and does not generate image smear even when the cumulative number of processing increases with long-term use.
The second object of the present invention is that the release agent is effectively leached onto the toner surface even when used in a high-speed machine, and meltability without occurrence of fixing wrap jam due to insufficient releasability, An object of the present invention is to provide an electrostatic image developing toner having excellent fluidity.
A third object of the present invention is to provide a toner for developing an electrostatic image having durability that does not cause release of a release agent from the toner.
A fourth object of the present invention is to provide a toner for developing an electrostatic image that can be used in a high-speed image forming apparatus having an oil / cleaning-less fixing process.
Furthermore, a fifth object of the present invention is to provide an image forming method using the toner.
[0014]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors focused on the structure of a polymerized toner having a sea-island structure obtained by associating the resin particles of the present invention with the crystalline substance particles after studying insomnia and rest. It has been found that the object of the present invention can be achieved by controlling and specifying the dispersed state of islands made of crystalline substances in the particles.
[0015]
That is, the present invention takes the form in which a crystalline substance that is an island in toner particles having a sea-island structure is arranged in a three-dimensional manner with an appropriate dispersion state without being biased in the toner particles. The present inventors have found that the toner can be optimally exuded out of the toner even if the toner is pressed from any direction at the time of formation, and as a result, the occurrence of offset is prevented.
[0016]
In the present invention, by adopting the configuration of any one of the following items, the islands present in the toner particles are finely dispersed at a very short distance interval, and in the toner particles, the regions where the islands exist densely or It is possible to obtain a sea-island toner in which the islands are in the same dispersed state in any region of the toner particles without forming uneven toner in the dispersed state having sparsely existing regions. It is a thing.
[0017]
  [1] In an electrostatic charge image developing toner containing at least a resin, a colorant, and a crystalline substance, the toner has an endothermic peak at 60 to 110 ° C. in a DSC curve and an endothermic amount of 4 to 30 J / g. The toner contains a crystalline materialObtained by multistage polymerizationResin particles and colorant particles are salted out / fused, the toner particles have a sea-island structure, and the islands made of crystalline substances in the toner particles are between the nearest walls between the islands. An electrostatic charge image developing toner, characterized in that an island having an average distance of 100 to 1060 nm and a distance between the nearest walls of 1300 nm or more is 10% by number or less of all the islands.
[0018]
  [2] In an electrostatic charge image developing toner containing at least a resin, a colorant, and a crystalline substance, the toner has an endothermic peak at 60 to 110 ° C. in a DSC curve and an endothermic amount of 4 to 30 J / g. The toner contains a crystalline materialObtained by multistage polymerizationResin particles and colorant particles are salted out / fused, and the toner particles have a sea-island structure, and an island made of a crystalline substance in the toner particles is the closest wall between the islands. A toner for developing an electrostatic charge image, characterized in that the average value of the distance between the islands is 260 to 820 nm, and the number of the islands whose distance between the nearest walls is 1300 nm or more is 4% by number of all the islands.
[0019]
  [3]As described in [1] or [2]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and the islands are not exposed on the surface of the toner particles.98% or more of toner particlesIt is characterized byStillToner for charge image development.
[0020]
  [4][1] to any one of [3]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and an average value of areas of Voronoi polygons formed by vertical bisectors between centroids of adjacent islands in the sea-island structure Is 20,000-120,000 nm²And the coefficient of variation of the area of the Voronoi polygon is 25% or less.StillToner for charge image development.
[0021]
  [5][1] to any one of [3]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and an average value of areas of Voronoi polygons formed by vertical bisectors between centroids of adjacent islands in the sea-island structure 40,000 to 100,000 nm²And the coefficient of variation of the area of the Voronoi polygon is 20% or less.StillToner for charge image development.
[0022]
  [6][1] to any one of [3]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and an average value of areas of Voronoi polygons formed by vertical bisectors between centroids of adjacent islands in the sea-island structure Is 20,000-120,000 nm²And 160,000 nm²It includes 3 to 20% by number of islands having the above area.StillToner for charge image development.
[0023]
  [7]In any one of the above [1] to [6]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and are formed by vertical bisectors between the centroids of the islands existing outside the circle having a radius of 1000 nm centered on the centroid of the toner particle cross section. The average value of the area of the Voronoi polygon formed is larger than the average value of the area of the Voronoi polygon formed by the perpendicular bisector between the centroids of the islands existing inside the circle.StillToner for charge image development.
[0024]
  [8][1] to any one of [7]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and among the Voronoi polygons formed by vertical bisectors between the centroids of adjacent islands in the sea-island structure, the outer periphery of the toner For a Voronoi polygon that is in contact with the surface, the area of the Voronoi polygon is 160,000 nm²It is characterized by the existence of 5 to 30 islandsStillToner for charge image development.
[0025]
  [9][1] to any one of [8]In the toner for developing an electrostatic image, the toner particles have a sea-island structure, and the island is composed of islands having different luminances.StillToner for charge image development.
[0027]
  [10]In the electrostatic image developing toner according to any one of [1] to [9],The toner has a number variation coefficient in the number particle size distribution of 27% or less and a shape coefficient variation coefficient of 16% or less.StillToner for charge image development.
[0029]
  [11]In the electrostatic image developing toner according to any one of [1] to [9],The toner is characterized in that the proportion of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, and the variation coefficient of the shape factor is 16% or less.StillToner for charge image development.
[0030]
  [12]In the electrostatic image developing toner according to any one of [1] to [11],The toner has a number average particle diameter of 3 to 9 μm.StillToner for charge image development.
[0031]
  [13]In the electrostatic image developing toner according to any one of [1] to [12],The toner has a logarithmic particle size distribution in which the natural logarithm lnD is taken on the horizontal axis when the particle size of the toner particles is D (μm), and the horizontal axis is divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of the toner particles contained in the most frequent class and the relative frequency (m2) of the toner particles contained in the next most frequent class is 70% or more. It is characterized by beingStillToner for charge image development.
[0034]
  [14] Previous[1]-[13The toner for developing an electrostatic image according to any one of the aboveInThe toner is a salted out / fused composite resin fine particle formed through a process of polymerizing a polymerizable monomer after dissolving a crystalline substance in at least a polymerizable monomer and a colored particle containing a colorant. An electrostatic charge image developing toner obtained by the method described above.
[0035]
  [15] Previous[1]-[14The toner for developing an electrostatic image according to any one of the aboveInThe toner for developing an electrostatic image, wherein the toner is obtained by salting out / fusing at least composite resin particles obtained by a multistage polymerization method and colorant particles.
[0036]
  [16] Previous[1]-[15The toner for developing an electrostatic image according to any one of the aboveInThe toner is obtained by forming a resin phase formed by fusing resin particles by a salting-out / fusing method on the surface of colored particles containing a resin and a colorant. Toner for charge image development.
[0037]
  [17] Previous[14] ~ [16Any one of the aboveFor electrostatic image developmentA method for producing a toner for developing an electrostatic image, comprising producing a toner.
[0038]
  [18In the image forming method comprising the steps of converting the electrostatic latent image formed on the photoreceptor into a visible image, transferring the visible image onto a recording medium, and fixing by heating, the visible imaging is performed as described in [1] to [1].16An image forming method comprising: using the toner for developing an electrostatic charge image according to any one of items 1 to 3 and performing heat fixing at a linear speed of 230 to 900 mm / sec.
[0039]
  [19And a step of converting the electrostatic latent image formed on the photoreceptor into a visible image, transferring the visible image onto a recording medium, and fixing the image by heating.18An image forming method according to claim 1, wherein the electrostatic latent image is formed by performing digital exposure on the photosensitive member.
[0040]
According to the present invention, by controlling the islands of the crystalline substance having releasability constituting the toner to be arranged in a three-dimensionally uniform manner in the toner particles, As a result of allowing the crystalline substance having releasability in the toner to bleed out isotropically and equally, regardless of the pressure direction, it is possible to prevent offset and gloss unevenness. It is a finding of the effect. The present invention will be described in detail below.
[0041]
The toner particles of the present invention have a sea-island structure. The sea-island structure is a structure in which an island-like phase having a closed interface (a boundary between phases) exists in a continuous phase. Say things. That is, in the toner of the present invention, each component of the resin, colorant, and crystalline substance constituting the toner particles is not compatible with each other and each forms a phase independently. It will have. In the present invention, the toner has a structure in which an island of a crystalline substance and an island of a colorant are present in a continuous phase of a resin that is the sea.
[0042]
In this way, the toner particles of the present invention adopt a structure in which a phase of another constituent component exists in an island shape in the continuous phase. By controlling the dispersibility of the crystalline substance islands in the toner particles by specifying the number of the contact diameters within the specified range, the amount of crystalline substances released from the toner particles is controlled. As a result, the crystalline substance added to the toner particles effectively exerts its function at the time of image formation, thereby suppressing the occurrence of filming of the photosensitive member by improving the offset property. The above problems have been achieved.
[0043]
That is, in the prior art, the crystalline substance added to the polymerized toner tended to hardly achieve appropriate dispersibility in the toner particles, but the present invention has solved this problem. In the present invention, the clear reason for achieving the isotropic and optimum dispersibility of the crystalline substance in the toner particles is not necessarily completely elucidated. It is presumed that an island that exhibits an optimal dispersion state could not be formed in the toner particles because the particles of the crystalline material thus tended to aggregate more easily. In the present invention, it is presumed that this problem has been solved by a mechanism that effectively controls the aggregation of the crystalline substances.
[0044]
In the present invention, the crystalline substance is not exposed on the surface of the toner particles, and having a uniform dispersibility within the particles effectively prevents the crystalline substance from being released from the toner particles at the same time. It is thought that it was achieved. The reason why the toner particles having such a structure can be formed is not completely elucidated, but the crystalline substance having releasability used in the toner of the present invention is probably contained inside the toner particles. It is presumed that the presence is held in the binder resin in a more stable state.
[0045]
Alternatively, even if a crystalline substance is present on the surface of the toner particles, the toner of the present invention is produced by heating to a temperature higher than the melting point of the crystalline substance in an aqueous medium. It is also assumed that the crystalline substance present on the toner particle surface when the aqueous medium is removed is also removed together with water.
[0046]
It is also presumed that the shape of the crystalline substance is also caused. That is, in the case of the prior art, the added crystalline substance has a spherical shape or a shape close to a spherical shape, so that the added crystalline substance particles easily move in the toner particles. Since the particles are spherical or have a shape close to a sphere, the contact area in the toner particles is small, so that the crystalline substance is not firmly held in the toner particles and is presumed to spill out from the particles.
[0047]
On the other hand, the toner particles of the present invention take a form in which the islands of the crystalline substance in the toner particles are firmly held in the particles, so that they are released from the toner particles except during the pressure fixing process. It is presumed that a function of allowing the toner particles to be stably and firmly held without causing the toner particles to exude quickly and reliably at the time of pressure fixing is given. In addition, due to the crystalline material having a releasing function that exudes moderately outside the toner particles, a protective layer made of a crystalline material having a low friction coefficient is formed on the surface of the fixed image. As a result, it is possible to prevent the occurrence of stains that occur when paper sheets with image information printed at the time of bookbinding are bundled and overlapped.
[0048]
The toner particles of the present invention have a sea-island structure because the toner particles have regions with different luminance based on a cross-sectional photograph of the toner particles taken with a transmission electron microscope. It can be confirmed that there is. That is, the toner particles of the present invention are obtained by using the transmission electron microscope, as shown in the schematic diagram of FIG. 1, in the continuous phase (binder resin phase) granular islands (crystalline substance phase, And a colorant phase) are present. Further, based on the results obtained from the observation result of the electron microscope, factors that specify the sea-island structure in the toner particles such as the number of islands in one toner particle, the shape factor of the island, and the distance between the closest walls of the island are numerical values. It is obtained as
[0049]
Luminance in a transmission electron micrograph is the visualization of the difference in electron beam transmissivity generated due to the difference in the crystalline state of each element constituting the toner particles, that is, the binder resin, the colorant, and the crystalline substance. In general, the colorant is photographed at a low luminance because the electron beam transmittance is lower than that of the binder resin, and the crystalline substance is photographed at a higher luminance than that of the binder resin.
[0050]
In an electron micrograph, low luminance means that the luminance signal of a pixel (pixel) is in 0 to 99 gradations when divided into 256 gradations, and medium luminance is in the range of 80 to 160 gradations, High brightness refers to one having 127 to 255 gradations, but in the present invention, it is not limited to the above range as long as it is a relative one, that is, any component that can distinguish the above-described toner particle components from photographs. It is not something. For example, when an island of a crystalline substance is placed in an environment at 80 to 120 ° C. for observation with a transmission electron microscope, it flows out and is observed as a void, so that it can be easily distinguished from an island of a colorant. .
[0051]
In this way, in the present invention, each component in the toner particles is identified based on the brightness, so that it is possible to visually determine and identify the sea as an ocean and the island as an island by an electron micrograph. The luminance information is converted into image information that can be visually identified by an image analysis apparatus installed in the electron microscope apparatus.
[0052]
FIG. 1 is a schematic diagram showing an example of toner particles having a sea-island structure according to the present invention. In an electron micrograph, the toner particles of the present invention are different in brightness from the continuous phase as shown in this schematic diagram. It is observed that it is composed of islands. In addition, there may be a region that does not have an island portion having a length a and a depth b along the outer periphery of the toner particle.
[0053]
In the present invention, the crystalline substance constituting the island portion is an organic compound having a melting point, and is preferably a hydrocarbon compound containing an ester group in its compound structure. The melting point of the crystalline substance in the toner particles of the present invention is a temperature lower than the softening point of the toner, specifically 130 ° C. or less. The organic compound preferably has an ester group in its structure, and includes a crystalline polyester compound.
[0054]
The toner of the present invention has an endothermic peak from 60 ° C. to 110 ° C. in the DSC curve, and the endothermic amount is 4 to 30 J / g. It can be confirmed that the crystalline substance constituting the island portion in the toner of the invention has a melting point, and further, it can be confirmed by means such as an X-ray diffractometer that it has crystallinity. Further, the crystalline substance contained in the toner of the present invention includes those that exhibit a function as a release agent during image formation.
[0055]
The melting point of such a crystalline substance is preferably 50 to 130 ° C., more preferably 60 to 110 ° C., and particularly preferably 70 to 98 ° C. In a toner containing a crystalline substance having a melting point in the range of 50 to 130 ° C., the melt viscosity can be lowered, the adhesion to paper or the like can be improved, and the crystalline substance is present. Even in this case, the high-temperature elastic modulus is maintained within a preferable range, so that good offset resistance is exhibited.
[0056]
When the melting point of the crystalline substance is less than 50 ° C., the fixability itself is improved, but the storability is lowered, causing a problem in practical use. On the other hand, when the melting point exceeds 130 ° C., the melting start temperature becomes high, so that the contribution to the improvement of the fixability is low and the effect of improving the fixability is reduced.
[0057]
Here, the melting point of the crystalline substance contained in the toner of the present invention is a value measured by a differential calorimeter (DSC), specifically, 10 ° C./min from 0 ° C. to 200 ° C. The temperature showing the maximum peak of the endothermic peak measured when the temperature is raised under the conditions (first temperature raising process) is defined as the melting point. This melting point coincides with the “endothermic peak (P1) in the first temperature rising process by DSC” described later.
[0058]
As a specific measuring device of the melting point, DSC-7 manufactured by PerkinElmer, Inc. can be exemplified. The specific method for measuring the melting point with a differential calorimeter (DSC) is as follows. As the temperature rise / cooling conditions, the sample was left at 0 ° C. for 1 minute, then heated to 200 ° C. at 10 ° C./min. The temperature showing the maximum endothermic peak measured at this time is defined as an endothermic peak P1 in the first temperature raising process. Then, after leaving at 200 ° C. for 1 minute, the temperature is lowered under the condition of 10 ° C./min, and the temperature showing the maximum exothermic peak measured at that time is defined as the exothermic peak P2 in the first cooling process.
[0059]
The crystalline substance used in the toner of the present invention preferably has an endothermic peak (P1) in the first temperature rising process by DSC at 50 to 130 ° C., particularly 60 to 110 ° C. Moreover, it is preferable that the exothermic peak (P2) in the 1st cooling process by DSC exists in 30-110 degreeC, especially 40-120 degreeC. Here, the relationship of P1 ≧ P2 is established between the endothermic peak (P1) and the exothermic peak (P2). The temperature difference (P1-P2) is not particularly limited, but is preferably 50 ° C. or less.
[0060]
By including a crystalline substance having the above thermal characteristics, it is possible to exhibit an excellent offset prevention effect (wide fixing temperature range) and an excellent fixing property (high fixing rate). In order to exert the effect of the present invention, it is preferable that the binder resin and the crystalline substance are present in a phase-separated state.
[0061]
That is, the crystalline substance dissolves sharply, and as a result, the melt viscosity of the whole toner can be lowered, and the fixability can be improved. Further, since they are phase-separated from each other, it is possible to suppress a decrease in elastic modulus on the high temperature side, so that the offset resistance is not impaired.
[0062]
When the endothermic peak (P1) is less than 50 ° C., since the melting temperature is low, the fixability is improved, but the storage stability is lowered. Further, when the endothermic peak (P1) is in a range exceeding 130 ° C., the melting temperature is high, and as a result, it is impossible to improve the fixability and the offset resistance.
[0063]
When the exothermic peak (P2) indicating the recrystallization state exists below 30 ° C., it cannot be recrystallized unless it is cooled to a considerably low temperature, and such a substance has a low crystallinity. Therefore, it cannot be contributed to the improvement of the fixing property. If the exothermic peak (P2) is in a range exceeding 110 ° C., the recrystallization temperature is too high, the so-called melting temperature is also increased, and the low-temperature fixability is impaired.
[0064]
Further, the differential calorimeter (DSC) can confirm the endothermic peak of the toner of the present invention, and at the same time can measure the endothermic amount, which is the amount of heat. In the toner of the present invention, the above endothermic peak can be measured. The endothermic amount at the time is 4 to 30 J / g, more preferably 6 to 24 J / g.
[0065]
The transmission electron microscope apparatus capable of observing the structure of the toner particles of the present invention is usually sufficiently observed by a model well known among those skilled in the art. For example, “LEM-2000 type (manufactured by Topcon Corporation)”, etc. Is used. In the present invention, values obtained from the results of transmission electron micrographs such as the number of island portions in the toner particles characterized by the present invention from the projection surface of 1000 or more toner particles at a magnification of 10,000 times. It is calculated.
[0066]
In the present invention, a photographing method using a transmission electron microscope is performed by a generally known method performed when measuring toner particles. That is, as a specific method for measuring the tomographic plane of the toner, the toner may be sufficiently dispersed in a room temperature curable epoxy resin, then embedded and cured, or dispersed in a styrene fine powder having a particle size of about 100 nm. After pressure forming, the block obtained is dyed with ruthenium tetroxide or osmium tetroxide if necessary, and then a flaky sample is cut out and transmitted using a microtome with diamond teeth The tomographic morphology of the toner was photographed using an electron microscope (TEM). The shape of the crystalline substance region in the toner particles is visually confirmed from the photograph, and an image taken by an image processing apparatus “Luzex F” (manufactured by Nireco Corporation) provided in the electron microscope apparatus. By calculating the information, the ferret diameter, number, and shape factor values of the islands in the toner particles can be obtained.
[0067]
By the above method, the structure of the toner particles of the present invention is specified. Hereinafter, factors that specify the structure of the toner particles of the present invention will be described in detail.
[0068]
In the toner of the present invention, the average value of the distance between the nearest walls in the island portion existing in the toner particles is 100 to 1060 nm, and the island where the distance between the nearest walls is 1300 nm or more is the whole island in the toner particles. 10% or less by weight. By satisfying this condition, the islands made of crystalline substances in the toner particles are finely dispersed uniformly in the particles while maintaining a reasonably short distance. Have achieved that. It can be visually confirmed from the above transmission electron micrograph that the islands in the toner of the present invention are finely dispersed with no variation in distance.
[0069]
In the toner of the present invention, the average value of the distance between the nearest walls is 100 to 1060 nm, and the number of islands where the distance between the nearest walls is 1300 nm or more is 10% by number or less of all the islands in the toner particles. In the toner of the present invention, there is no unevenness in the dispersion of the islands in the toner particles, such as where there are many islands of crystalline material in the particles and where there are almost no islands. It means that. That is, in the present invention, it is confirmed that the islands are dispersed in an optimum state without unevenness in the toner particles.
[0070]
The distance between the closest walls of the islands in the toner of the present invention refers to the distance between the interfaces of adjacent islands in the toner particles, as indicated by arrows in the schematic diagram of FIG.
[0071]
Further, according to the present invention, the average value of the distance between the nearest walls in the toner particles is 260 to 820 nm, and the number of islands where the distance between the nearest walls is 1300 nm or more is four of all the islands in the toner. % Or less, the dispersibility of the islands in the toner particles is further improved, and more effective leaching of the crystalline substance is achieved in the fixing step.
[0072]
In the present invention, the number of islands whose distance between the nearest walls is 1300 nm or more may be 0% by number. That is, the number of islands whose distance between the nearest walls is 1300 nm or more is 0% by number means that the islands in the toner particles are finely dispersed in a completely uniform state with a short distance. It is.
[0073]
In the toner of the present invention, the islands in the toner have an average value of the distance between the nearest walls of 100 to 1060 nm, and the number of islands having the distance between the nearest walls of 1300 nm or more is 10% by number of all the islands in the toner. It has been found that the percentage of the crystalline substance constituting the island portion not exposed on the toner particle surface is 98% or more of the total when
[0074]
Since the crystalline substance islands are not exposed on the surface of the toner particles, the islands have a structure that is less likely to be detached from the toner particles. It should be noted that the exposure situation from the toner particle surface of the island and the presence of 98% or more of the unexposed toner particles are obtained by the above-described image analysis apparatus based on the above-mentioned transmission electron microscope observation results. is there. The present invention has found the above relationship based on the result of observing the surface of 1000 toner particles.
[0075]
Further, as described above, the toner of the present invention has islands of colorant components that can be distinguished from electron micrographs due to the difference in brightness in addition to the islands of crystalline substances. This is indicated by island B in the schematic diagram of FIG. As is apparent from this schematic diagram, in the toner particles having the sea-island structure of the present invention, a plurality of types of toner component islands may be present, that is, a crystalline substance island and a colorant component island. Since these different types of islands have different brightness, they can be easily identified in an electron micrograph.
[0076]
The island B of the colorant component in the toner particles of the present invention is specified based on the area of the Voronoi polygon described below, and the area related to the area of the Voronoi polygon is also the island of the crystalline substance. Similarly, it is calculated by an image analyzer attached to the electron microscope apparatus based on the image information observed by the transmission electron microscope apparatus.
[0077]
The area of the Voronoi polygon used in the present invention indicates the state of occupancy of islands in the toner particles. A Voronoi polygon or Voronoi polyhedron is, for example, a perpendicular bisector of adjacent points when many points are dispersed in space or on a plane, as described in the Iwanami Physical and Chemical Dictionary, By creating a perpendicular bisector, the entire space is divided into polyhedrons, or the entire plane is divided into polygons. And the division of the plane is called Voronoi division. FIG. 2 shows an example of the toner particles of the present invention divided by Voronoi polygons.
[0078]
As described above, in the present invention, the occupancy state of the island portion in the sea-island structure of the toner particle is indicated by the area of the Voronoi polygon obtained by Voronoi division as a scale representing the ratio of the island portion in the toner particle. . That is, in the present invention, focusing on the center of gravity of the islands present in the toner particles, polygons are formed by vertical bisectors formed by connecting the centers of gravity of adjacent islands, and the areas of these polygons are transmitted through the transmission area. This is calculated by an image analysis apparatus installed in the electron microscope apparatus based on the result of the photograph taken by the scanning electron microscope.
[0079]
The large area of the Voronoi polygon means that the distance between the centers of gravity of adjacent islands is long, that is, the sparse state of the occupied state of the island part in the particle. It is shown. In addition, the small area of the Voronoi polygon means that the distance between the centroids of adjacent islands is short and close, that is, the occupied state of the islands in the particles is dense. Is. In the present invention, for the Voronoi polygons at the islands in the toner particles, 1000 toners are measured, and the average value per toner particle is calculated.
[0080]
In addition, when the Voronoi polygon is generally defined mathematically, it is defined by the following formula.
<Area of Voronoi polygon>
The set of Voronoi polygons V (i) for N independent points P (i) (1 ≦ i ≦ N) in the two-dimensional space R2 or the three-dimensional space R3 is
V (i) = {X || XP (i) | <| XP (j) | for all
i to j}
(In the formula, X and P are position vectors, and || represents a distance in Euclidean space.)
It is assumed that V (i) defined in this way forms a Voronoi polygon at R2, and a Voronoi polyhedron at R3. When V (i) and V (j) are adjacent, the boundary of the Voronoi polygon is It is defined as a part of a perpendicular bisector of a line segment connecting P (i) and point P (j). The Euclidean space is as defined and described in the Mathematical Science Dictionary.
[0081]
Further, the center of gravity of the toner particles of the present invention and the center of gravity of each island in the toner particles are obtained by the moment of the image, and are automatically calculated by the image analysis apparatus installed in the transmission electron microscope apparatus. Here, the barycentric coordinates of the toner particles are obtained by multiplying the brightness value of a minute area at an arbitrary point of the toner particles by the coordinate value of the arbitrary point. Then, the product of the brightness and the coordinate value is obtained for all coordinates existing in the entire toner particles, and the sum of the products is the brightness of the toner particles (the sum of the brightness values at the respective coordinate points obtained as described above). It is required by dividing. Similarly, for the center of gravity of the island, the center of gravity of the island is also calculated by obtaining the luminance at an arbitrary coordinate point in the island. As described above, the center-of-gravity coordinates of the toner particles of the present invention and the center-of-gravity coordinates of each island present in the toner particles are calculated based on the luminance at each arbitrary point, that is, from the brightness of the image.
[0082]
In the present invention, the average value of the area of the Voronoi polygon formed by the perpendicular bisector between the centroids of adjacent islands in the toner particles is 20,000 to 120,000 nm.²And the coefficient of variation of the average value of the area is 25% or less. In the present invention, the variation coefficient of the area of the Voronoi polygon is calculated by the following equation.
The coefficient of variation of the area of the Voronoi polygon = {S1 / K1} × 100 (%)
[In the formula, S1 represents the standard deviation of the area of the Voronoi polygon in the island portion present in the toner particles, and K1 represents the average value of the area of the Voronoi polygon. ]
[0083]
Further, the average value of Voronoi polygon areas of adjacent islands in the toner particles of the present invention is more preferably 40,000 to 100,000 nm.²And the coefficient of variation is 20% or less.
[0084]
Further, in the toner particles of the present invention, the average value of the Voronoi polygon areas of adjacent islands in the toner particles is 20,000 to 120,000 nm.²And 160,000 nm²The island forming the Voronoi polygon having the above area is 3 to 20% by number of the whole island, and preferably 50,000 nm from the viewpoint of making the charge amount distribution uniform.²The islands forming Voronoi polygons having the following areas are 30% by number or more, more preferably 60% by number or more of the whole islands present in one toner particle.
[0085]
The average value of the area of the Voronoi polygon formed by the perpendicular bisector between the centroids of adjacent islands in the toner particles of the present invention is 20,000 to 120,000 nm.²However, if it is out of this range, the occupancy of the islands in the toner particles becomes unfavorable. For example, a colorant present as an island in the particles is effective in the toner particles. This is not preferable because it is difficult to find the effect of the present invention.
[0086]
The variation coefficient of the average value of the area of the Voronoi polygon formed from the adjacent islands in the toner particles of the present invention specifies the variation in the area of the Voronoi polygon, that is, the occupation of the island portion in the toner particles The variation of the state is specified, and the variation coefficient of the average value of the area of the Voronoi polygon may be 25% or less, and preferably 20% or less. When the coefficient of variation is 0%, that is, in a state where there is no variation in the average value of the Voronoi polygon area, in other words, in a state where there is no variation in the occupied state of the islands in the toner particles, all the toner particles There is no need to have the same occupation.
[0087]
In the present invention, if the variation coefficient of the average value of the area of the Voronoi polygon exceeds 25%, that is, the variation between the areas of the obtained Voronoi polygon becomes too large, the effect of the present invention is found at the time of image formation. It becomes extremely difficult to do so.
[0088]
In the present invention, the area of the Voronoi polygon is 160,000 nm.²The above-mentioned islands are 3 to 20% by number of the whole islands present in one toner particle, which means that the islands are moderately dispersed in the toner particles. In this way, the islands are appropriately spaced from each other, meaning that the islands are not unevenly distributed in the toner particles and that the colorant is effectively added to the toner particles. is there.
[0089]
In the present invention, the area of the Voronoi polygon formed by the islands existing within the specific range from the center of gravity of the toner particles is smaller than the area of the Voronoi polygon formed by the islands existing outside the range. It is characterized by being. That is, in the present invention, the average value of the areas of Voronoi polygons formed by islands existing within a radius of 1000 nm from the gravity center of the toner particles is the average value of the areas of Voronoi polygons formed by islands existing within a radius of 1000 nm. This means that in the toner particles, the dispersed state of the islands is sparse at some distance from the center of gravity of the toner particles. By satisfying these conditions, in the toner of the present invention, the effect achieved by the present invention can be found by appropriately dispersing islands in the toner particles.
[0090]
In the toner of the present invention, the toner particles have a sea-island structure, but have a region where no island exists in the region along the outer periphery of the toner particles. In the schematic diagram of FIG. 1, the region indicated by the length a and the depth b along the outer periphery of the cross section of the toner particle is a region that does not include an island. That is, it is confirmed that the toner of the present invention has a region that does not include any island part along the outer periphery of the cross section of the toner particle. The region has a depth of 100 to 200 nm, more preferably a depth of 120 to 180 nm. The length is 500 to 6000 nm, more preferably 800 to 4000 nm.
[0091]
In the toner of the present invention, it is presumed that the island is not particularly present in a specific region along the outer periphery of the toner particle, thereby effectively preventing the island from spilling from the toner particle. Further, it is presumed that the effect found in the present invention is promoted by appropriately dispersing the colorant added to the toner particles in the particles, and the region along the outer periphery of the cross section of the toner particles. If it does not have, the island tends to fall off from the toner particles, and the problem of the present invention tends to be difficult to find.
[0092]
The colorant used in the toner of the present invention is a fine particle dispersion that is made into a fine particle state having a weight average particle diameter of 30 to 500 nm in the toner production process, and is added to the toner particles. A specific description of the production method in which the colorant fine particles have the weight average particle diameter will be described later.
[0093]
Next, the shape of the toner of the present invention will be described in detail.
The toner particles used in the present invention have a shape coefficient variation coefficient of 16% or less, and toner composed of toner particles having a number variation coefficient of 27% or less in the number particle size distribution is used. The presence of the external additive becomes uniform, the charge amount distribution becomes sharp, and high fluidity is obtained. As a result, it is excellent in developability and fine line reproducibility, and stable cleaning properties can be formed over a long period of time.
[0094]
Further, as a result of investigations by paying attention to the minute shape of each toner particle, the present inventors have changed the shape of the corner portion of the toner particle to become round inside the developing device, and this portion becomes an external additive. As a result, it was found that the change in charge amount, fluidity and cleaning properties were reduced.
[0095]
In addition, when charge is applied to the toner particles by frictional charging, it is presumed that the external additive tends to be buried particularly in the corner portions, and the toner particles are likely to be non-uniformly charged. That is, by using toner composed of toner particles in which the number of toner particles having no corners is 50% by number or more and the number variation coefficient in the number particle size distribution is controlled to 27% or less, developability and fine line reproduction are also achieved. It has been found that a high-quality image can be formed over a long period of time.
[0096]
Further, it has been found that even when the toner is made to have a specific shape, the external additive is not buried and the charge amount distribution becomes sharp. That is, even when toner having a shape factor of 1.2 to 1.6 in which the proportion of toner particles is 65% by number or more and the variation coefficient of the shape factor is 16% or less, developability, fine line It has been found that images with excellent reproducibility and high image quality can be formed over a long period of time.
[0097]
Here, the number particle size distribution and the number variation coefficient of the toner of the present invention will be described. The number particle size distribution and the number variation coefficient of the toner of the present invention are measured by a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, a Coulter multisizer was used, and an interface (manufactured by Nikka Kisha Co., Ltd.) for outputting the particle size distribution and a personal computer were connected. The aperture used in the Coulter Multisizer was 100 μm, and the volume diameter and number diameter of 2 μm or more were measured to calculate the particle size distribution and average particle size. The number particle size distribution represents the relative frequency of toner particles with respect to the particle size, and the number average particle size represents a cumulative 50% diameter in the number particle size distribution, that is, Dn50.
[0098]
The number variation coefficient in the toner number particle size distribution is calculated from the following equation.
Number variation coefficient = [S / Dn] × 100 (%)
[In the formula, S represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm). ]
[0099]
The number variation coefficient of the toner of the present invention is 27% or less, preferably 25% or less. When the number variation coefficient is 27% or less, voids in the transferred toner layer are reduced, fixing properties are improved, and offset is less likely to occur. In addition, the charge amount distribution becomes sharp, the transfer efficiency is increased, and the image quality is improved.
[0100]
The method for controlling the number variation coefficient of the present invention is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of using a centrifuge and controlling the number of revolutions to separate and adjust the toner particles according to the difference in sedimentation speed caused by the difference in toner particle diameter.
[0101]
Next, the shape factor of the toner of the present invention will be described. In the toner of the present invention, the proportion of toner particles having a shape factor in the range of 1.2 to 1.6 is 65 number% or more, the variation coefficient of the shape factor is 16% or less, and the number in the number particle size distribution. The coefficient of variation is 27% or less. Here, the shape factor of the toner of the present invention is represented by the following formula, and indicates the degree of roundness of the toner particles.
Shape factor = ((maximum diameter / 2)²× π) / projection area
[0102]
Here, the maximum diameter refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines. The projected area refers to the area of the projected image of the toner particles on the plane. In the present invention, this shape factor is obtained by taking a photograph in which the toner particles are magnified 2000 times with a scanning electron microscope, and then using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. It was measured by performing analysis. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.
[0103]
Next, toner particles having no corners will be described for the toner of the present invention. Here, the toner particles having no corners are toner particles that do not substantially have protrusions that concentrate electric charges or protrusions that easily wear due to stress. That is, as shown in FIG. When the major axis of the toner particle T is L, the circle C having a radius (L / 10) rolls inward while touching the inner line at one point with respect to the peripheral line of the toner particle T. A case where the toner does not substantially protrude outside the toner T is referred to as “toner particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less.
[0104]
The “major diameter of toner particles” refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on a plane is sandwiched between two parallel lines. 8B and 8C show projection images of toner particles having corners, respectively.
[0105]
The measurement of toner without corners was performed as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000-fold photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 1000 toner particles.
[0106]
In the toner of the present invention, the proportion of toner particles having no corners is 50% by number or more, preferably 70% by number or more. When the ratio of toner particles having no corners is 50% by number or more, generation of fine particles is less likely to occur due to stress with the developer conveying member and the like, and so-called contamination on the surface of the developer conveying member is suppressed. In addition, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.
[0107]
A method for obtaining toner having no corners is not particularly limited. For example, as described above as a method for controlling the shape factor, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy by impact force in a gas phase, or a toner is dissolved. It can be obtained by adding in a solvent that does not, and applying a swirling flow.
[0108]
In the toner of the present invention, when the particle diameter of the toner particles is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the distribution, the sum (M) of the relative frequency (m1) of the toner particles contained in the most frequent class and the relative frequency (m2) of the toner particles contained in the next most frequent class after the most frequent class. The toner is preferably 70% or more.
[0109]
When the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow. Therefore, selective development can be performed by using the toner in the image forming process. Can be reliably suppressed.
[0110]
In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to a computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.
〔Measurement condition〕
1: Aperture: 100 μm
2: Sample preparation method: Electrolytic solution [ISOTON II (manufactured by Coulter Scientific Japan)] A suitable amount of a surfactant (neutral detergent) is added to 50 to 100 ml and stirred, and 10 to 20 mg of a measurement sample is added thereto. This system is prepared by dispersing for 1 minute with an ultrasonic disperser.
[0111]
Next, the particle diameter of the toner of the present invention will be described. The toner used in the present invention has a number average particle diameter of 3 to 9 μm, preferably 4.5 to 8.5 μm, and more preferably 5 to 8 μm. This particle size can be controlled by the concentration of the flocculant (salting-out agent), the amount of organic solvent added, the fusing time, and the polymer composition in the toner production method.
[0112]
When the number average particle diameter is 3 to 9 μm, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved. Calculation of the particle size distribution of the toner and measurement of the number average particle size are performed using a Coulter Counter TA-II, Coulter Multisizer (both manufactured by Coulter), SLAD1100 (Laser diffraction type particle size measuring device manufactured by Shimadzu Corporation) and the like. Can be measured. In the present invention, a Coulter Multisizer is used to measure and calculate an interface (manufactured by Nikkaki Co., Ltd.) that outputs a particle size distribution and a personal computer.
[0113]
Next, a method for producing the toner of the present invention will be described.
The toner of the present invention is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. In this production method, resin particles are prepared by polymerizing a polymerizable monomer by a suspension polymerization method. Alternatively, the emulsion resin of the required additives is added (in an aqueous medium), and the monomer is emulsion polymerized or miniemulsion polymerized to prepare fine resin particles, and charged as necessary. After adding the controllable resin particles, an organic solvent, an aggregating agent such as a salt, and the like are added to produce the resin particles by agglomeration and fusion.
[0114]
<Suspension polymerization method>
As an example of a method for producing the toner of the present invention, a charge control resin is dissolved in a polymerizable monomer, and various constituent materials such as a colorant, a mold release agent, and a polymerization initiator are added. Then, various constituent materials are dissolved or dispersed in the polymerizable monomer using a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction device (stirring device) which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare the toner of the present invention. In the present invention, the “aqueous medium” refers to a medium containing at least 50% by mass of water.
[0115]
<Emulsion polymerization method>
Further, as a method for producing the toner of the present invention, a method in which resin particles are prepared by salting out / fusion in an aqueous medium can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of salting out, agglomerating, and fusing a plurality of fine particles composed of resin particles and colorants, or a constituent material such as resin particles and a colorant, and in particular using an emulsifier in water Then, a coagulant with a critical coagulation concentration or higher is added for salting out, and at the same time, the formed polymer is heated and fused at a temperature higher than the glass transition temperature of the polymer itself to gradually grow the particle size while forming fused particles. When the desired particle size is reached, a large amount of water is added to stop 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.
[0116]
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 at least dissolving the crystalline substance in the polymerizable monomer are salted out / It is obtained by fusing. The toner of the present invention dissolves a crystalline substance in a polymerizable monomer, but it may be dissolved and dissolved or melted and dissolved.
[0117]
The toner production method of the present invention is to salt out / fuse the composite resin fine particles obtained by the multistage polymerization method and the colorant particles. The multistage polymerization method will be described below.
[0118]
<Method for producing composite resin particles obtained by multistage polymerization method>
The toner manufacturing method of the present invention comprises the following steps.
1: Multistage polymerization process
2: A salting out / fusing step for obtaining toner particles by salting out / fusing the composite resin particles and the colorant particles.
3: Filtration / washing step of separating the toner particles from the toner particle dispersion and removing the surfactant from the toner particles.
4: a drying process for drying the washed toner particles;
5: Step of adding an external additive to the dried toner particles
Consists of
Hereinafter, each step will be described in detail.
[0119]
[Multistage polymerization process]
The multi-stage polymerization step is a polymerization method performed for expanding the molecular weight distribution of the resin particles so as to obtain a toner in which offset generation 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.
[0120]
In the present invention, it is preferable to employ a multi-stage polymerization method of three-stage polymerization or more from the viewpoint of production stability and crushing strength of the resulting toner. Hereinafter, the two-stage polymerization method and the three-stage polymerization method, which are representative examples of the multistage polymerization method, will be described. The toner obtained by such a multistage polymerization reaction preferably has a lower molecular weight as the surface layer from the viewpoint of crushing strength.
[0121]
<Two-stage polymerization method>
The two-stage polymerization method is a method for producing composite resin particles composed of a central portion (core) formed from a high molecular weight resin containing a crystalline substance and an outer layer (shell) formed from a low molecular weight resin. is there.
[0122]
This method will be described in detail. First, a crystalline substance is dissolved in a monomer to prepare a monomer solution, and the monomer solution is added to oil droplets 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 containing a crystalline substance.
[0123]
Next, a polymerization initiator and a monomer for obtaining a low molecular weight resin are added to the dispersion of the resin particles, and the monomer is polymerized in the presence of the resin particles (second-stage polymerization). Thus, a coating layer made of a low molecular weight resin (monomer polymer) is formed on the surface of the resin particles.
[0124]
<Three-stage polymerization method>
The three-stage polymerization method produces composite resin particles composed of a central part (core) formed from a high molecular weight resin, an intermediate layer containing a crystalline substance, and an outer layer (shell) formed from a low molecular weight resin. Is the method. The toner of the present invention exists as the composite resin particles as described above.
[0125]
This method will be specifically described. First, a dispersion of resin particles obtained by a polymerization process (first-stage polymerization) according to a conventional method is added to an aqueous medium (for example, an aqueous solution of a surfactant). In the aqueous medium, a monomer solution obtained by dissolving a crystalline substance in a monomer is dispersed in oil droplets, and then this system is polymerized (second-stage polymerization) to obtain resin particles (cores). A coating layer (intermediate layer) made of a resin (monomer polymer) containing a crystalline substance is formed on the surface of the particles, and a dispersion of composite resin particles (high molecular weight resin-intermediate molecular weight resin) is prepared. Prepare.
[0126]
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). ), A coating layer made of a low molecular weight resin (monomer polymer) is formed on the surface of the composite resin particles. In the above method, the incorporation of the intermediate layer is preferable because the crystalline substance can be finely and uniformly dispersed.
[0127]
One feature of the toner production method according to the present invention is that the polymerizable monomer is polymerized in an aqueous medium. That is, when forming resin particles (core particles) or a coating layer (intermediate layer) containing a crystalline substance, the crystalline substance is dissolved in the monomer, and the resulting monomer solution is oiled in an aqueous medium. It is a method of obtaining latex particles by dispersing in drops and adding a polymerization initiator to this system for polymerization treatment.
[0128]
The aqueous medium as used in the field of this invention means the medium which consists of 50-100 mass% of water and 0-50 mass% of water-soluble organic solvents. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, and an alcohol-based organic solvent that does not dissolve the obtained resin is preferable.
[0129]
As a suitable polymerization method for forming resin particles or a coating layer containing a crystalline substance, the crystalline substance is 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. A method (hereinafter referred to as “mini-emulsion method” in the present invention), and the effects of the present invention can be exhibited more preferably. In the above method, an oil-soluble polymerization initiator may be used instead of or together with the water-soluble polymerization initiator.
[0130]
According to the mini-emulsion method that mechanically forms oil droplets, unlike the usual emulsion polymerization method, the crystalline substance dissolved in the oil phase has little detachment and is sufficient in the formed resin particles or coating layer. Any amount of crystalline material can be introduced.
[0131]
Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, the stirring device “CLEARMIX” (M technique (M Co., Ltd.), ultrasonic disperser, mechanical homogenizer, manton gorin, pressure homogenizer, and the like. The dispersed particle diameter is 10 to 1000 nm, preferably 50 to 1000 nm, and more preferably 30 to 300 nm. Here, by providing a distribution of the dispersed particle diameter, the phase separation structure of the crystalline substance in the toner particles is controlled uniformly so that a specific value does not have a peak in the distance between the nearest walls. .
[0132]
In addition, as other polymerization methods for forming resin particles or a coating layer containing a crystalline substance, known methods such as an emulsion polymerization method, a suspension polymerization method, and a seed polymerization method can be employed. These polymerization methods can also be employed to obtain resin particles (core particles) or coating layers constituting the composite resin particles that do not contain a crystalline substance.
[0133]
The particle diameter of the composite resin particles obtained in this polymerization step is in the range of 10 to 1000 nm in terms of mass average particle diameter measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). Is preferred.
[0134]
Moreover, it is preferable that the glass transition temperature (Tg) of a composite resin particle exists in the range of 48-74 degreeC, More preferably, it is 52-64 degreeC.
The softening point of the composite resin particles is preferably in the range of 95 to 140 ° C.
[0135]
The toner of the present invention is obtained by forming a resin layer formed by fusing resin particles on the surface of the resin and colored particles by a salting-out / fusing method. This will be described below.
[0136]
[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 toner particles.
[0137]
In the present invention, salting out / fusion means that salting out (aggregation of particles) and fusion (disappearance of the interface between particles) occur simultaneously, or act of causing salting out and fusion at the same time. . In order to perform salting-out and fusion at the same time, it is necessary to agglomerate particles (composite resin particles, colorant particles) under a temperature condition higher than the glass transition temperature (Tg) of the resin constituting the composite resin particles. .
[0138]
In this salting-out / fusion process, 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.
[0139]
[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 crystalline substance, preferably the melting point ± 20 ° C., and stirring is continued at a constant strength. This is a step of phase-separating the crystalline substance. Also in this step, it is possible to control the dispersibility of the crystalline substance in the toner particles.
[0140]
[Colorant fine particles]
The colorant fine particles used for obtaining the toner of the present invention are formed using a dispersing device for finely dispersing the colorant fine particles in an aqueous medium containing a surfactant. That is, the dispersing apparatus shown in FIG. 3 is an example of a dispersing apparatus that finely disperses the fine colorant particles preferably used in the toner of the present invention, and includes a screen that forms a stirring chamber and a rotor that rotates at high speed in the stirring chamber. A shearing force is generated, and fine particles are obtained by finely dispersing the colorant in an aqueous medium containing a surfactant by the action of the shearing force (further impact force, pressure fluctuation, cavitation, potential core action). It is.
[0141]
Here, the surfactant contained in the aqueous medium in which the colorant fine particles are dispersed is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC), and the surfactant used is used in the polymerization step. The same one can be used.
[0142]
The weight average particle diameter (dispersion particle diameter) of the colorant fine particles is 30 to 500 nm, preferably 50 to 300 nm. When the weight average particle diameter of the colorant fine particles is less than 30 nm, the colorant floats in the aqueous system severely, and when the weight average particle diameter exceeds 500 nm, the colorant particles are moderately contained in the aqueous system. Since it is easy to settle without being dispersed, it is difficult to introduce the colorant into the toner particles. Under such conditions, the colorant particles are not preferred because they remain free in the aqueous system without being taken into the toner particles. The weight average particle diameter of the colorant fine particles is measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).
[0143]
The fine colorant particles used in the toner of the present invention are prepared by first adding a colorant into an aqueous medium containing a surfactant and then preliminarily dispersing (coarse dispersion) with a propeller stirrer or the like. A dispersed predispersion is produced. A preferable dispersion state is obtained by supplying the preliminary dispersion to a stirrer including a screen that forms a stirrer chamber and a rotor that rotates at a high speed in the stirrer chamber, and performing a dispersion process (fine dispersion process) using the stirrer. A dispersion of colorant fine particles having the following is prepared:
[0144]
In the present invention, “CLEARMIX” (manufactured by M Technique Co., Ltd.) can be mentioned as a stirring device for dispersion treatment for obtaining colorant fine particles having a preferable dispersion state. This “Clearmix” has a rotor (stirring blade) that rotates at a high speed and a fixed screen (fixed ring) that surrounds the rotor, and a shearing force, collision force, pressure fluctuation, cavitation and It has a structure that imparts the action of a potential core, and these actions function synergistically to effectively emulsify and disperse the liquid to be treated.
[0145]
That is, this “Clear mix” is originally used for the production of emulsion (dispersion of liquid fine particles), but the present inventors use it as an apparatus for dispersing solid colorant fine particles in an aqueous medium. Thus, it has been found that a dispersion of colorant fine particles having a preferable average particle size and a sharp particle size distribution can be obtained.
[0146]
FIG. 3A is a schematic diagram showing a rotor that rotates at a high speed and a fixed screen that surrounds the rotor. In FIG. 3, 101 is a screen, M is a stirring chamber partitioned by the screen 101, 102. Indicates a rotor rotating at high speed in the stirring chamber M.
[0147]
The rotor 102 is a stirring blade that rotates at a high speed, and its rotation speed is usually 4,500 to 22,000 rpm, preferably 10,000 to 21,500 rpm. The tip peripheral speed of the rotor 2 is normally 10 to 40 m / sec, preferably 15 to 30 m / sec.
[0148]
The screen 101 arranged so as to surround the rotor 102 is formed of a fixed ring composed of a large number of slits (not shown). The width of the slit is 0.5 to 5 mm, preferably 0.8 to 2 mm. Moreover, the number of slits is 10-50, Preferably it is 15-30. The gap (clearance) between the rotor 102 and the screen 101 is usually 0.1 to 1.5 mm, preferably 0.2 to 1.0 mm.
[0149]
The average particle size and particle size distribution of the colorant fine particles are adjusted by controlling the number of revolutions of the rotor 102, and can be adjusted by selecting the shapes of the screen 101 and the rotor 102. Specifically, the screen (S1.0-24, S1.5-24, S1.5-18, S2.0-18, S3.0-9) and the rotor (R1), which are standard equipment in “CLEARMIX”, are provided. Although a preferable dispersion state is obtained by combination with ~ R4), it may be produced in-house to obtain a more preferable dispersion state.
[0150]
FIG.3 (b) is a schematic diagram which shows the continuous processing apparatus (Clear mix) provided with the rotor and the screen. The predispersed dispersion liquid (preliminary dispersion liquid) is supplied from a preliminary dispersion liquid inlet 104 shown in FIG. 3B to a stirring chamber between the screen 101 and the rotor. The screen 101 and the rotor are surrounded by a pressurized vacuum attachment 103, and a temperature sensor 106, a cooling jacket 107, and a cooling coil 108 are disposed. The agglomerated particles of the colorant in the preliminary dispersion are crushed (finely dispersed) by applying a shearing force generated by the rotor rotating at high speed and the screen 101.
[0151]
That is, the colorant-aggregated particles in the preliminary dispersion supplied to the band-shaped stirring chamber located between the screen 101 and the rotor are subjected to shear force (mechanical energy) generated by high-speed rotation of the screen 101 and the rotor. In addition to the shearing force, it is crushed (finely dispersed) into fine colorant particles by the action of impact force, pressure fluctuation, cavitation and potentio core. The dispersion liquid of the colorant fine particles is ejected from the slit of the screen 101 into the pressurized vacuum attachment 103 to obtain a dispersion liquid of the colorant fine particles having a preferable average particle diameter and sharp particle diameter distribution. The dispersion liquid containing the colorant fine particles is sent to the next process from the dispersion liquid outlet 105.
[0152]
In the stirrer due to the action of the rotor and the screen, the colorant agglomerated particles are crushed to form fine colorant particles (dispersed particles) having a preferred average particle size and sharp particle size distribution. The formation mechanism is as follows. This is due to the multiple actions shown.
[0153]
(1) Near the surface of the rotor (stirring blade) that rotates at high speed, the velocity gradient is large, so a high-speed shear rate region is formed near the surface, and the colorant aggregated particles are crushed by the shearing force generated in this region. .
[0154]
(2) Behind the rotor (stirring blade), if the rotational speed is high, a vacuum part (cavitation) is generated, and the bubbles generated by the rotation disappear at the stage where the flow rate of the dispersion liquid is reduced. Along with this, an impact pressure is generated, and the aggregated particles of the colorant are crushed by the impact pressure.
[0155]
(3) The rotor (stirring blade) imparts pressure energy to the preliminary dispersion by its high-speed rotation. However, if the pressure energy is suddenly released, the kinetic energy of the preliminary dispersion increases, and the preliminary dispersion flowing by the rotor is a screen. When repeatedly passing between the open portion (slit portion) and the sealed portion (non-slit portion), pressure energy is changed to generate pressure waves to break up the aggregated particles of the colorant.
[0156]
(4) When the pre-dispersion liquid having a large kinetic energy collides with the screen or other walls, the aggregated particles of the colorant subjected to the collision force are crushed and become colorant fine particles having a sharp particle size distribution.
[0157]
(5) When the dispersion having velocity energy passes through the slit portion of the screen, it becomes a jet (jet flow). In the potential core (velocity region not affected by the viscous flow) in the jet, the surrounding fluid is sucked at a high speed. The agglomerated particles of the colorant that have received this energy are crushed and become fine colorant particles having a sharp particle size distribution.
[0158]
The dispersion time for obtaining the colorant fine particle dispersion is not particularly limited, but is 5 to 30 minutes, preferably 7 to 25 minutes. Moreover, when circulating, 5 paths or more are preferable, More preferably, it is 5-20 paths. If the dispersion time is too long, the dispersion becomes excessive and the abundance of fine particles increases, which is not preferable.
[0159]
Further, in order to obtain colorant fine particles preferably used for the toner of the present invention, a dispersion container having a stirring device equipped with a screen and a rotor is used, and the stirring is performed in an aqueous medium accommodated in the dispersion container. You may perform the batch-type dispersion | distribution process which ejects a coloring agent (aqueous medium containing a coloring agent) from the stirring chamber of an apparatus.
[0160]
FIG.3 (c) is a schematic diagram which shows the dispersion | distribution container provided with such a stirring apparatus (Clear mix), and a dispersion process is performed by such an apparatus. In FIG. 3C, 111 is a dispersion vessel, 112 is a stirring device, and 113 is a stirring shaft for driving the stirring device 112. The stirring device 112 has the same configuration (screen and rotor) as that shown in FIG.
[0161]
The preliminary dispersion (dispersion of the colorant aggregated particles) enters the stirring chamber from the upper part of the stirring device 112 and is stirred by the strong shearing force, impact force and turbulence generated between the rotor rotating at high speed and the screen. Colorant fine particles having a weight average particle diameter of 30 to 300 nm are formed and ejected into the dispersion container 111 from the slits of the screen. In the dispersion step of the colorant fine particles, the dispersion container 111 may have a jacket structure, and the temperature in the dispersion container 111 may be controlled by flowing warm water or steam into the jacket, and if necessary, cold water.
[0162]
In the case of performing batch-type dispersion processing using the dispersion container shown in FIG. 3C, the colorant ejection direction from the stirring chamber of the stirring device 112 (the ejection direction of the colorant fine particles into the aqueous medium) Is preferably in the downward or horizontal direction. By ejecting the colorant (colorant fine particles) downward or in the horizontal direction, the aqueous medium in the dispersion container 111 flows as indicated by an arrow F. As a result, the colorant is ejected downward, and the flow follows the wall. And then recirculates into the Claremix. For this reason, a dispersion | distribution process can be repeated reliably and dispersion | distribution energy can be provided uniformly. As a result, it is estimated that the dispersion diameter of the colorant can be made uniform. Thereby, the colorant fine particles having a sharp particle size distribution can be efficiently formed.
[0163]
In this way, the colorant particles preferably used in the present invention are crushed by the action of shearing force generated by the screen and the rotor, and the suitable average particle diameter (weight average particle diameter: 30 to 30). 500 nm) and a dispersion of colorant fine particles (fine particles close to primary particles) having a sharp particle size distribution (standard deviation (σ) of 30 or less) is obtained, and such colorant fine particles (dispersed particles) are obtained as resin fine particles. By subjecting the toner particles to salting out / fusion, colorant fine particles are surely introduced into the toner particles to be formed, and the introduced colorant particles are not released, and the colorant is contained between the toner particles. There is no variation in the ratio.
[0164]
As a result, even when the toner of the present invention is used for image formation under high temperature and high humidity or after a long period of non-use of the apparatus, image defects such as fogging due to toner charge amount fluctuations and fine dot dust are generated. There is no. Furthermore, in the present invention, since the colorant fine particles are dispersed in the toner particles without using the medium, image defects caused by the remaining fine impurities such as the fragmented pieces of the medium in the toner do not occur.
[0165]
The colorant particles are subjected to a salting out / fusion process in a state of being dispersed in an aqueous medium. The aqueous medium in which the colorant particles are dispersed is preferably an aqueous solution in which the surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC).
[0166]
The disperser used for the dispersion treatment of the colorant particles is not particularly limited, but preferably a stirring device “CLEARMIX” (manufactured by M Technique Co., Ltd.) equipped with a rotor rotating at high speed, ultrasonic dispersion And pressure dispersers such as a mechanical homogenizer, manton gourin, and pressure homogenizer, and medium dispersers such as a Getzman mill and a diamond fine mill.
[0167]
In order to salt out / fuse the composite resin particles and the colorant particles, a salting-out agent (flocculating agent) having a critical aggregation concentration or more is added to the dispersion in which the composite resin particles and the colorant particles are dispersed. In addition, it is necessary to heat the dispersion to a temperature higher than the glass transition temperature (Tg) of the composite resin particles.
[0168]
The temperature range suitable for salting out / fusion is (Tg + 10) to (Tg + 50 ° C.), and particularly preferably (Tg + 15) to (Tg + 40 ° C.). In addition, an organic solvent that is infinitely soluble in water may be added in order to effectively perform fusion.
[0169]
In the present invention, resin particles and a colorant are salted out, aggregated, and fused in an aqueous medium to obtain colored particles (referred to as toner particles in the present invention), and then the toner particles are separated from the aqueous medium. When performing, it is preferable to carry out at the temperature more than the craft point of the surfactant which exists in an aqueous medium, More preferably, it is carrying out in the temperature range of a craft point-(craft point +20 degreeC).
[0170]
The Kraft point is a temperature at which an aqueous solution containing a surfactant starts to become cloudy, and the Kraft point is measured as follows.
<Measurement of craft point>
A solution was prepared by adding the actual amount of the flocculant to the aqueous medium, that is, the surfactant solution used in the salting out, agglomeration and fusion processes, and this solution was stored at 1 ° C. for 5 days. The solution was then gradually heated with stirring until clear. The temperature at which the solution becomes clear is defined as the Kraft point.
[0171]
The toner for developing an electrostatic charge image of the present invention is described above in order to stabilize and maintain the chargeability particularly with respect to the environment from the viewpoint of suppressing excessive charge to the toner particles and imparting uniform chargeability. It is preferable to contain 250 to 20000 ppm, more preferably 800 to 5000 ppm in the toner.
[0172]
Moreover, in this invention, it is preferable that the total value of the bivalent (trivalent) metal element used for a coagulant | flocculant and the monovalent | monohydric metal element added as an aggregation terminator mentioned later is 350-35000 ppm. The residual amount of metal ions in the toner is measured 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 toners having a known content ratio of the flocculant metal salt are prepared, each toner 5g is pelletized, the content ratio (mass ppm) of the flocculant metal salt, and the metal species of the metal salt The relationship (calibration curve) with the fluorescent X-ray intensity (peak intensity) is measured. Next, the toner (sample) whose content of the flocculant metal salt is to be measured is similarly pelletized, and the fluorescent X-ray intensity from the metal species of the flocculant metal salt is measured. Amount "can be determined.
[0173]
[Filtering and washing process]
In this filtration / washing step, a filtration treatment for filtering the toner particles from the toner particle dispersion obtained in the above step, and a surfactant or salt from the filtered toner particles (cake-like aggregate). A cleaning process for removing deposits such as a depositing agent is performed. 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.
[0174]
[Drying process]
This step is a step of drying the washed toner particles.
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.
[0175]
The water content of the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.
In addition, when the toner particles that have been dried are aggregated due to weak interparticle attraction, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
[0176]
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.
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. Therefore, according to the toner of the present invention, the excellent offset resistance is not impaired, and the fixing device is not contaminated or the image is not stained due to the accumulation of toner.
[0177]
In addition, as a result of the polymerization reaction for obtaining the composite resin particles being reliably performed, no monomer or oligomer remains in the obtained toner particles, and the heat fixing step of the image forming method using the toner In this case, no odor is generated.
Furthermore, since the surface characteristics of the obtained toner particles are uniform and the charge amount distribution is sharp, an image with excellent sharpness can be formed over a long period of time. According to such a toner having a uniform composition, molecular weight, and surface characteristics between toner particles, an image forming method including a fixing process using a contact heating method maintains good adhesion (high fixing strength) to an image support. However, it is possible to improve the anti-offset property and the anti-winding property, and an image having an appropriate gloss can be obtained.
[0178]
Next, each component used in the toner manufacturing process will be described in detail.
(Polymerizable monomer)
As a polymerizable monomer for producing the resin (binder) used in the present invention, a hydrophobic monomer is an essential constituent, and a crosslinkable monomer is used as necessary. Moreover, it is desirable to contain at least one monomer having an acidic polar group or a monomer having a basic polar group in the structure as described below.
[0179]
(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.
[0180]
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.
[0181]
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.
[0182]
Examples of (meth) acrylic acid ester monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, Examples include ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. It is done.
[0183]
Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl benzoate, and examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, and the like. It is done.
[0184]
Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene, and the diolefin monomer includes butadiene, isoprene, Examples include chloroprene.
[0185]
(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.
[0186]
(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).
[0187]
Examples of the α, β-ethylenically unsaturated compound having a carboxyl group (a) include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid Examples thereof include monooctyl esters and metal salts thereof such as Na and Zn.
[0188]
Examples of the α, β-ethylenically unsaturated compound having a sulfone group (b) include sulfonated styrene and its Na salt, allylsulfosuccinic acid, allylsulfosuccinic acid octyl, and their Na salts. it can.
[0189]
(4) Monomers having basic polar groups
As the monomer having a basic polar group, (a) 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. , (B) (meth) acrylic acid amide or (meth) acrylic acid amide mono- or disubstituted with an alkyl group having 1 to 18 carbon atoms optionally on N, (c) a heterocyclic ring having N as a ring member Examples thereof include a vinyl compound substituted with a group and (d) N, N-diallyl-alkylamine or a quaternary ammonium salt thereof. Among them, (a) (meth) acrylic acid ester of an aliphatic alcohol having an amine group or a quaternary ammonium group is preferable as a monomer having a basic polar group.
[0190]
Examples of (meth) acrylic acid esters of aliphatic alcohols having an amine group or quaternary ammonium group (a) 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.
[0191]
(B) (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.
[0192]
Examples of the vinyl compound substituted with a heterocyclic group having N as a ring member in (c) include vinylpyridine, vinylpyrrolidone, vinyl-N-methylpyridinium chloride, vinyl-N-ethylpyridinium chloride and the like.
[0193]
Examples of N, N-diallyl-alkylamine in (d) include N, N-diallylmethylammonium chloride, N, N-diallylethylammonium chloride and the like.
[0194]
(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. By using a redox initiator, the polymerization activity can be increased, the polymerization temperature can be lowered, and the polymerization time can be shortened.
[0195]
The polymerization temperature is not particularly limited as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but it is, for example, in the range of 50 ° C to 90 ° C. However, it is also possible to polymerize at room temperature or higher by using a polymerization initiator that starts at room temperature in combination with a hydrogen peroxide-reducing agent (such as ascorbic acid).
[0196]
(Chain transfer agent)
A known chain transfer agent can be used for the purpose of adjusting the molecular weight. Although it does not specifically limit as a chain transfer agent, For example, the compound which has mercapto groups, such as an octyl mercaptan, a dodecyl mercaptan, a tert- dodecyl mercaptan, is used. In particular, a compound having a mercapto group is preferably used because it suppresses odor during heat-fixing, gives a toner having a sharp molecular weight distribution, and is excellent in storage stability, fixing strength, and offset resistance. Preferable examples include ethyl thioglycolate, propyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate , A compound having a mercapto group of ethylene glycol, a compound having a mercapto group of neopentyl glycol, and a compound having a mercapto group of pentaerythritol. Among these, n-octyl-3-mercaptopropionic acid ester is particularly preferable from the viewpoint of suppressing odor during toner heat fixing.
[0197]
(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.
[0198]
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).
[0199]
In the present invention, surfactants represented by the following general formulas (1) and (2) are particularly preferably used.
General formula (1) R¹(OR²)_nOSO_ThreeM
General formula (2) R¹(OR²)_nSO_ThreeM
[0200]
In the general formulas (1) and (2), R¹Represents an alkyl group or arylalkyl group having 6 to 22 carbon atoms, preferably an alkyl group or arylalkyl group having 8 to 20 carbon atoms, more preferably an alkyl group or arylalkyl group having 9 to 16 carbon atoms. is there.
[0201]
R¹Examples of the alkyl group having 6 to 22 carbon atoms represented by: n-hexyl group, n-heptyl group, n-octyl group, n-decyl group, n-undecyl group, n-hexadecyl group, cyclopropyl group , Cyclopentyl group, cyclohexyl group and the like, and R¹Examples of the arylalkyl group represented by the formula include a benzyl group, a diphenylmethyl group, a cinnamyl group, a styryl group, a trityl group, and a phenethyl group.
[0202]
In the general formulas (1) and (2), R²Represents an alkylene group having 2 to 6 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms. R²Examples of the alkylene group having 2 to 6 carbon atoms represented by: ethylene group, trimethylene group, tetramethylene group, propylene group, ethylethylene group and the like.
[0203]
In general formula (1), (2), n is an integer of 1-11, Preferably it is 2-10, More preferably, it is 2-5, Most preferably, it is 2-3.
[0204]
In the general formulas (1) and (2), examples of the monovalent metal element represented by M include sodium, potassium, and lithium. Of these, sodium is preferably used.
[0205]
Specific examples of the surfactant represented by the general formulas (1) and (2) are shown below, but the present invention is not limited thereto.
Compound (101): C_TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeNa
Compound (102): C_TenH_{twenty one}(OCH₂CH₂)_ThreeOSO_ThreeNa
Compound (103): C_TenH_{twenty one}(OCH₂CH₂)₂SO_ThreeNa
Compound (104): C_TenH_{twenty one}(OCH₂CH₂)_ThreeSO_ThreeNa
Compound (105): C₈H₁₇(OCH₂CH (CH_Three))₂OSO_ThreeNa
Compound (106): C₁₈H₃₇(OCH₂CH₂)₂OSO_ThreeNa
[0206]
In the present invention, from the viewpoint of maintaining the charge holding function of the toner in a good state, suppressing fogging under high temperature and high humidity, and improving transferability, and suppressing the increase in charge amount under low temperature and low humidity, developing From the viewpoint of stabilizing the amount, the content of the surfactant represented by the general formulas (1) and (2) in the toner for developing an electrostatic charge image is preferably 1 to 1000 ppm, more preferably 5 It is -500 ppm, Most preferably, it is 7-100 ppm.
[0207]
In the present invention, by setting the amount of the surfactant to be contained in the toner within the above described range, the chargeability of the electrostatic image developing toner of the present invention is always uniform without being influenced by environmental influences. It can be applied and maintained in a stable state.
[0208]
Further, the content of the surfactant represented by the above general formulas (1) and (2) contained in the toner for developing an electrostatic charge image of the present invention is calculated by the following method.
1 g of toner is dissolved in 50 ml of chloroform, and the surfactant is extracted from the chloroform layer with 100 ml of ion exchange water. Further, the extracted chloroform layer is extracted once again with 100 ml of ion-exchanged water to obtain a total of 200 ml of extract (water layer), and this extract is diluted to 500 ml.
Using this diluted solution as a test solution, in accordance with the method defined in JIS 33636, color was developed with methylene blue, the absorbance was measured, and the surfactant content in the toner was measured from a separately prepared calibration curve. is there.
[0209]
Moreover, the structure of the surfactant represented by the general formulas (1) and (2) was determined by analyzing the above extract using 1H-NMR.
[0210]
In the present invention, a metal salt can be preferably used as an aggregating agent in a step of salting out, agglomerating, and fusing resin particles from a dispersion of resin particles prepared in an aqueous medium. More preferably, a metal salt is used as the flocculant. The reason is that a divalent or trivalent metal salt is preferable to a monovalent metal salt because the critical aggregation concentration (coagulation value or coagulation point) is smaller.
[0211]
In the present invention, a nonionic surfactant can also be used. Specifically, polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, Examples include higher fatty acid and polyethylene glycol esters, higher fatty acid and polypropylene oxide esters, and sorbitan esters.
[0212]
In the present invention, these surfactants are mainly used as an emulsifier during emulsion polymerization, but may be used for other steps or for other purposes.
[0213]
(Molecular weight distribution of resin particles and toner)
The toner of the present invention preferably has a molecular weight distribution peak or shoulder at 100,000 to 1,000,000 and 1,000 to 50,000, and further has a molecular weight distribution peak or shoulder of 100. It is preferable that it exists in 1,000,000,000, 25,000-150,000, and 1,000-50,000.
[0214]
The molecular weight of the resin particles is both a high molecular weight component having a peak or shoulder in the region of 100,000 to 1,000,000 and a low molecular weight component having a peak or shoulder in the region of 1,000 to less than 50,000. Is preferable, and it is preferable to use an intermediate molecular weight resin having a peak or a shoulder at a portion of 15,000 to 100,000.
[0215]
As a method for measuring the molecular weight of the toner or resin described above, GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a solvent is preferable. That is, 1.0 ml of THF is added to 0.5 to 5 mg of a measurement sample, more specifically 1 mg, and the mixture is sufficiently dissolved by stirring at room temperature using a magnetic stirrer or the like. Subsequently, after processing with a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., flowing THF at a flow rate of 1.0 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. The column is preferably used in combination with a commercially available polystyrene gel column. For example, Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 made by Showa Denko KK, TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be mentioned. As a detector, a refractive index detector (IR detector) or a UV detector may be used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points may be used as polystyrene for preparing a calibration curve.
[0216]
(Flocculant)
In the present invention, a metal salt can be preferably used as an aggregating agent in a step of salting out, agglomerating, and fusing resin particles from a dispersion of resin particles prepared in an aqueous medium. More preferably, a metal salt is used as the flocculant. The reason is that a divalent or trivalent metal salt is preferable to a monovalent metal salt because the critical aggregation concentration (coagulation value or coagulation point) is smaller.
[0217]
The flocculant used in the present invention is a monovalent metal salt which is a salt of an alkali metal such as sodium, potassium or lithium, for example, a salt of an alkaline earth metal such as calcium or magnesium, or a divalent such as manganese or copper. Examples thereof include metal salts and trivalent metal salts such as iron and aluminum.
[0218]
Specific examples of these metal salts are shown below. Examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride, and examples of the divalent metal salt include calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. Examples thereof include aluminum chloride and iron chloride. These are appropriately selected according to the purpose, but divalent or trivalent metal salts having a small critical aggregation concentration are preferable.
[0219]
The critical flocculation concentration referred to in the present invention is an index relating to the stability of the dispersion in the aqueous dispersion, and indicates the concentration of the flocculating agent added when the flocculating agent 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.
[0220]
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.
[0221]
In the present invention, the metal salt concentration 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.
[0222]
(Coloring agent)
The toner of the present invention is obtained by salting out / fusion-bonding the composite resin particles and the colorant particles. Examples of the colorant constituting the toner of the present invention (colorant particles used for salting out / fusion with 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.
[0223]
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.
[0224]
These inorganic pigments can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably 3-15 mass% is selected.
[0225]
When used as a magnetic toner, the above-mentioned magnetite can be added. In this case, it is preferable to add 20 to 60% by mass in the toner from the viewpoint of imparting predetermined magnetic properties.
[0226]
Conventionally known organic pigments and dyes can also be used, and specific organic pigments and dyes are exemplified below.
[0227]
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.
[0228]
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.
[0229]
Examples of the pigment for green or cyan 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.
[0230]
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.
[0231]
These organic pigments and dyes can be used alone or in combination as required. Moreover, the addition amount of a pigment is 2-20 mass% with respect to a polymer, Preferably it is 3-15 mass%.
[0232]
The colorant (colorant particles) constituting the toner of the present invention may be surface-modified. A conventionally well-known thing can be used as a surface modifier, Specifically, a silane coupling agent, a titanium coupling agent, an aluminum coupling agent etc. can be used preferably. Examples of the silane coupling agent include alkoxysilanes such as methyltrimethoxysilane, phenyltrimethoxysilane, methylphenyldimethoxysilane, and diphenyldimethoxysilane, siloxanes such as hexamethyldisiloxane, γ-chloropropyltrimethoxysilane, vinyltrimethyl. Chlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureido Examples thereof include propyltriethoxysilane. Examples of titanium coupling agents include TTS, 9S, 38S, 41B, 46B, 55, 138S, and 238S, which are commercially available under the trade name “Plenact” manufactured by Ajinomoto Co., Inc. -1, B-1, TOT, TST, TAA, TAT, TLA, TOG, TBSTA, A-10, TBT, B-2, B-4, B-7, B-10, TBSTA-400, TTS, TOA -30, TSDMA, TTAB, TTOP and the like. Examples of the aluminum coupling agent include “Plenact AL-M” manufactured by Ajinomoto Co., Inc.
[0233]
The addition amount of these surface modifiers is preferably 0.01 to 20% by mass, more preferably 0.1 to 5% by mass with respect to the colorant. Examples of the surface modification method for 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 and reacted. The colorant particles whose surface has been modified in this manner are obtained by filtration, and after drying and filtering with the same solvent are repeated, drying is performed.
[0234]
(Crystalline substance)
The toner used in the present invention is preferably a toner in which resin particles containing a crystalline substance are fused in an aqueous medium and the crystalline substance is appropriately aggregated by an aging step to form a sea-island structure. . As described above, the resin particles containing the crystalline substance in the resin particles are salted out / fused in the aqueous medium with the colorant particles, whereby a toner in which the crystalline substance is finely dispersed can be obtained. Here, the aging step refers to a step in which stirring is continued in the range of the melting point of the crystalline substance ± 20 ° C. even after the resin particles are fused.
[0235]
In the toner of the present invention, low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyethylene, and the like are preferable as the crystalline substance having a releasing function, and particularly preferably an ester compound represented by the following formula: is there.
R₁-(OCO-R₂)_n
In the formula, n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and 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.
[0236]
Next, the example of a typical compound is shown below.
[Chemical 1]

[0237]
[Chemical formula 2]

[0238]
In the present invention, crystalline polyester can also be used as the crystalline substance. As the crystalline polyester, aliphatic diol and aliphatic dicarboxylic acid (including acid anhydride and acid chloride) are used. Polyester obtained by reaction is preferred.
[0239]
Examples of the diol used to obtain the crystalline polyester include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,4-butenediol. , Neopentyl glycol, 1,5-pentane glycol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A and the like.
[0240]
Dicarboxylic acids used to obtain crystalline polyesters include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, citraconic acid , Itaconic acid, glutamic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, acid anhydrides or acid chlorides thereof Can be mentioned.
[0241]
Particularly preferred crystalline polyesters include polyesters obtained by reacting 1,4-cyclohexanedimethanol and adipic acid, polyesters obtained by reacting 1,6-hexanediol and sebacic acid, ethylene glycol and succinic acid. And polyester obtained by reacting ethylene glycol and sebacic acid, polyester obtained by reacting 1,4-butanediol and succinic acid, among these, Most preferred is a polyester obtained by reacting 1,4-cyclohexanedimethanol and adipic acid.
[0242]
The amount of the compound added is 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass with respect to the whole toner.
[0243]
(Developer)
The toner of the present invention may be used as a one-component developer or a two-component developer. When used as a one-component developer, the non-magnetic one-component developer or about 0.1 to 0.5 μm in the toner is used. Examples thereof include a magnetic one-component developer containing magnetic particles.
[0244]
It can also be mixed with a carrier and used as a two-component developer. In this case, as magnetic particles of the carrier, metals such as iron, ferrite and magnetite, alloys of these metals with metals such as aluminum and lead, etc. Conventionally known materials can be used. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.
[0245]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0246]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.
[0247]
Next, an image forming apparatus used in the image forming method using the toner of the present invention will be described.
[0248]
FIG. 4 is a sectional view showing an example of the image forming apparatus of the present invention. Reference numeral 4 denotes a photosensitive drum as a member to be charged, which is formed by forming an organic photoconductor (OPC) as a photosensitive layer on the outer peripheral surface of an aluminum drum base, and rotates at a predetermined speed in the direction of an arrow. .
[0249]
In FIG. 4, exposure light is emitted from the semiconductor laser light source 1 based on information read by a document reading device (not shown). This is distributed in the direction perpendicular to the paper surface of FIG. 4 by the polygon mirror 2 and irradiated onto the surface of the photoreceptor through an fθ lens 3 that corrects image distortion to form an electrostatic latent image. The photosensitive drum 4 is uniformly charged in advance by the charger 5 and starts to rotate clockwise in accordance with the timing of image exposure.
[0250]
The electrostatic latent image on the surface of the photosensitive drum is developed by the developing device 6, and the formed developed image is transferred to the transfer paper 8 that has been conveyed in time by the action of the transfer device 7. Further, the photosensitive drum 4 and the transfer paper 8 are separated by a separator (separation pole) 9, but the developed image is transferred and supported on the transfer paper 8 and led to the fixing device 10 to be fixed.
[0251]
Untransferred toner or the like remaining on the surface of the photoreceptor is cleaned by a cleaning device 11 of a cleaning blade type, removed residual charge by pre-charge exposure (PCL) 12, and again by the charger 5 for the next image formation. Uniformly charged.
[0252]
The method for recycling the toner is not particularly limited. For example, the toner collected by the cleaning unit is mixed with a replenishing toner hopper, a developing device or a replenishing toner by an intermediate chamber by a conveying conveyor or a conveying screw. And a method for supplying the developer to the developing device. Preferably, a method of returning directly to the developing unit or a method of mixing and supplying the replenishing toner and the recycled toner in the intermediate chamber can be given.
[0253]
Next, in FIG. 5, an example of a perspective configuration diagram of a toner recycling member is given. In this method, the recycled toner is directly returned to the developing unit.
[0254]
The untransferred toner collected by the cleaning blade 13 is collected on the toner recycling pipe 14 by the conveying screw in the toner cleaning device 11, and further returned to the developing device 6 from the receiving port 15 of the recycling pipe and used again as a developer. .
[0255]
FIG. 5 is also a perspective view of a process cartridge detachably attached to the image forming apparatus of the present invention. In FIG. 5, the photosensitive unit and the developer unit are separated for easy understanding of the perspective structure. However, the unit can be detachably mounted on the image forming apparatus as an integrated unit. In this case, the photosensitive member, the developing device, the cleaning device, and the recycling member are integrated to form a process cartridge.
[0256]
In addition, the image forming apparatus may be configured to include a photosensitive drum and a process cartridge including at least one of a charging device, a developing device, a cleaning device, and a recycling member.
[0257]
Next, the transfer paper is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and of course includes an OHP PET base.
[0258]
The cleaning blade 13 uses a rubber-like elastic body having a thickness of about 1 to 30 mm, and urethane rubber is most often used as the material. Since this is used in pressure contact with the photoconductor, it is easy to transfer heat. In the present invention, it is desirable to provide a release mechanism and keep it away from the photoconductor when no image forming operation is performed.
[0259]
The present invention can also be used in an electrophotographic image forming apparatus, particularly an apparatus for forming an electrostatic latent image on a photosensitive member with a modulated beam modulated with digital image data from a computer or the like. FIG. 6 is a schematic view showing a digital image forming apparatus applied to the toner of the present invention.
[0260]
In recent years, in the field of electrophotography where an electrostatic latent image is formed on a photosensitive member and the latent image is developed to obtain a visible image, image quality can be improved, converted, edited, etc., and high-quality image formation is possible. Research and development of image forming methods adopting various digital methods have been actively conducted.
[0261]
As a scanning optical system that optically modulates with a digital image signal from a computer or a copy original employed in the image forming method and apparatus, an optical optical modulator is interposed in the laser optical system, and the optical modulation is performed by the acoustooptic modulator. There is an apparatus that directly modulates the laser intensity using a semiconductor laser, and forms a dot image by spot exposure on a uniformly charged photoconductor from these scanning optical systems.
[0262]
The beam irradiated from the scanning optical system described above has a circular or elliptical luminance distribution that approximates a normal distribution with a skirt extending from side to side. For example, in the case of a laser beam, the main scanning direction or One or both in the sub-scanning direction is an extremely narrow circle or ellipse of 20 to 100 μm.
[0263]
The toner of the present invention is suitably used in an image forming method including a step of fixing an image forming support on which a toner image is formed between a heating roller and a pressure roller constituting a fixing device. The linear velocity can be used within a fixing speed range of 230 to 900 mm / sec.
[0264]
FIG. 7 is a cross-sectional view showing an example of a fixing device used in the image forming method using the toner of the present invention. The fixing device 10 shown in FIG. 7 includes a heating roller 71 and a pressure roller 72 in contact with the heating roller 71. And. In FIG. 7, T is a toner image formed on a transfer paper (image forming support).
[0265]
The heating roller 71 has a coating layer 82 made of a fluororesin or an elastic body formed on the surface of the cored bar 81 and includes a heating member 75 made of a linear heater.
The cored bar 81 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 81, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.
[0266]
The thickness of the cored bar 81 is set to 0.1 to 15 mm, and is determined in consideration of the balance between the demand for energy saving (thinning) and the strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.
[0267]
Examples of the fluororesin constituting the coating layer 82 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).
[0268]
The thickness of the coating layer 82 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm.
[0269]
When the thickness of the coating layer 82 made of a fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and the durability as the fixing device cannot be ensured. On the other hand, there is a problem that the surface of the coating layer exceeding 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched part, thereby causing image smearing.
[0270]
Further, as the elastic body constituting the covering layer 82, it is preferable to use silicone rubber, silicone sponge rubber, or the like having good heat resistance such as LTV, RTV, HTV.
[0271]
The Asker C hardness of the elastic body constituting the covering layer 82 is less than 80 °, preferably less than 60 °.
[0272]
Moreover, the thickness of the coating layer 82 made of an elastic body is 0.1 to 30 mm, preferably 0.1 to 20 mm.
[0273]
When the Asker C hardness of the elastic body constituting the coating layer 82 exceeds 80 ° and when the thickness of the coating layer 82 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is performed. (For example, the effect of improving the color reproducibility by the toner layer at the smoothed interface) cannot be exhibited.
[0274]
As the heating member 75, a halogen heater can be preferably used. The pressure roller 72 is formed by forming a coating layer 84 made of an elastic body on the surface of the cored bar 83. The elastic body constituting the covering layer 84 is not particularly limited, and examples thereof include various soft rubbers and sponge rubbers such as urethane rubber and silicone rubber. The silicone rubber exemplified as constituting the covering layer 84 and It is preferable to use silicone sponge rubber.
[0275]
The Asker C hardness of the elastic body constituting the coating layer 84 is less than 80 °, preferably less than 70 °, and more preferably less than 60 °.
[0276]
The thickness of the coating layer 84 is 0.1 to 30 mm, preferably 0.1 to 20 mm.
[0277]
When the Asker C hardness of the elastic body constituting the coating layer 84 exceeds 80 °, and when the thickness of the coating layer 84 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is not performed. The effect cannot be demonstrated.
[0278]
Although it does not specifically limit as a material which comprises the metal core 83, Metals, such as aluminum, iron, copper, or those alloys can be mentioned.
[0279]
The contact load (total load) between the heating roller 10 and the pressure roller 72 is usually 40 to 350 N, preferably 50 to 300 N, and more preferably 50 to 250 N. This contact load is defined in consideration of the strength of the heating roller 10 (the thickness of the cored bar 81). For example, in a heating roller having a cored bar made of iron of 0.3 mm, the contact load should be 250 N or less. Is preferred.
[0280]
From the viewpoint of offset resistance and fixing property, the nip width is preferably 4 to 10 mm, and the surface pressure of the nip is 0.6 × 10 6.^FivePa ~ 1.5 × 10^FivePa is preferred.
[0281]
If an example of the fixing conditions by the fixing device shown in FIG. 7 is shown, the fixing temperature (surface temperature of the heating roller 10) is 150 to 210 ° C., and the fixing linear velocity is 230 to 900 mm / sec.
[0282]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the text, “part” means “part by mass”.
[0283]
Production example of resin particles for toner
[Latex 1HML]
(1) Preparation of core particles (first stage polymerization):
Anionic surfactant in a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet
(101) C_TenH_{twenty one}(OCH₂CH₂)₂OSO_ThreeNa
A surfactant solution (aqueous medium) in which 7.08 g was dissolved in 3010 g of ion-exchanged water was charged, and the temperature in the flask was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0284]
To this surfactant solution, an initiator solution prepared by dissolving 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., and then 70.1 g of styrene, n -A monomer mixture consisting of 19.9 g of butyl acrylate and 10.9 g of methacrylic acid was added dropwise over 1 hour, and this system was polymerized by heating and stirring at 75 ° C for 2 hours (first stage polymerization). And a latex (a dispersion of resin particles made of a high molecular weight resin) was prepared. This is referred to as “latex (1H)”.
[0285]
(2) Formation of intermediate layer (second stage polymerization);
In a flask equipped with a stirrer, 105.6 g of styrene, 30.0 g of n-butyl acrylate, 6.2 g of methacrylic acid, 5.6 g of n-octyl-3-mercaptopropionic acid ester, As a crystalline substance, 98.0 g of a compound represented by the above formula (19) (hereinafter referred to as “Exemplary Compound (19)”) is added, heated to 90 ° C. and dissolved to prepare a monomer solution. did.
[0286]
On the other hand, a surfactant solution obtained by dissolving 1.6 g of an anionic surfactant (the above formula (101)) in 2700 ml of ion-exchanged water is heated to 98 ° C., and a dispersion of core particles is added to the surfactant solution. After adding 28 g of the latex (1H) in terms of solid content, the compound (19) of the exemplified compound (19) was simply added by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. The monomer solution was mixed and dispersed for 8 hours to prepare a dispersion (emulsion) containing emulsified particles (oil droplets).
[0287]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion exchange water and 750 ml of ion exchange water are added to this dispersion (emulsion). Polymerization (second-stage polymerization) was performed by heating and stirring for 12 hours to obtain latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin was covered with an intermediate molecular weight resin). This is referred to as “latex (1HM)”.
[0288]
When the latex (1HM) was dried and observed with a scanning electron microscope, particles (400 to 1000 nm) mainly composed of the exemplified compound (19) not surrounded by the latex were observed.
[0289]
(3) Formation of outer layer (third stage polymerization):
An initiator solution obtained by dissolving 7.4 g of a polymerization initiator (KPS) in 200 ml of ion-exchanged water is added to the latex (1HM) obtained as described above, and 300 g of styrene under a temperature condition of 80 ° C. A monomer mixture composed of 95 g of n-butyl acrylate, 15.3 g of methacrylic acid, and 10.4 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and latex (a central part made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, A dispersion of composite resin particles having an outer layer made of a molecular weight resin and containing the exemplary compound (19) in the intermediate layer was obtained, and this latex is referred to as “latex (1HML)”.
[0290]
The composite resin particles constituting the latex (1HML) had peak molecular weights of 138,000, 80,000 and 13,000, and the weight average particle size of the composite resin particles was 122 nm.
[0291]
[Latex 2HML]
Latex (center consisting of high molecular weight resin) in the same manner as in Preparation Example 1 except that 7.08 g of an anionic surfactant (sodium dodecylbenzenesulfonate: SDS) was used instead of the surfactant (101). Part, 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 “latex (2HML)”.
[0292]
The composite resin particles constituting the latex (2HML) had peak molecular weights of 138,000, 80,000 and 12,000, and the weight average particle size of the composite resin particles was 110 nm.
[0293]
[Production of colored particles 1 to 13 and comparative colored particles 1 to 4]
Anionic surfactant (101) 59.0 g was dissolved in 1600 ml of ion-exchanged water with stirring, and while stirring this solution, 420.0 g of carbon black “Regal 330” (manufactured by Cabot) was gradually added. A dispersion of colorant particles (hereinafter referred to as “colorant dispersion 1”) was prepared by dispersion treatment using “CLEAMIX” (manufactured by M Technique Co., Ltd.). When the particle diameter of the colorant particles in this colorant dispersion was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 89 nm.
[0294]
Latex 1HML 420.7g (solid content conversion), ion-exchanged water 900g, colorant dispersion 1 166g in a reaction vessel (four-necked flask) equipped with a temperature sensor, cooling tube, nitrogen introducing device, and stirring device. The mixture was stirred. After adjusting the temperature in the container to 30 ° C., a 5N sodium hydroxide aqueous solution was added to this solution to adjust the pH to 8 to 10.0.
[0295]
Next, an aqueous solution obtained by dissolving 12.1 g of magnesium chloride hexahydrate in 1000 ml of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. After standing for 3 minutes, the temperature was started to rise, and the system was heated to 90 ° C. over 6 to 60 minutes to produce associated particles. In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II”, and when the number average particle size became 4 to 7 μm, an aqueous solution in which 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. Was added to stop the particle growth, and further, as a ripening treatment, the mixture was heated and stirred at a liquid temperature of 85 to 98 ° C. for 2 to 12 hours to continue particle fusion and crystalline phase separation (aging). Process).
[0296]
Then, it cooled to 30 degreeC, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped. The produced associated particles were filtered, repeatedly washed with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to obtain colored particles.
[0297]
By controlling the pH of the agglomeration step, the temperature of the aging treatment step, the aging time, and the stirring strength, the coefficient of variation of the crystalline substance, the colorant dispersion state, the shape and the shape factor is controlled, Colored particles 1 to 13 consisting of colored particles having dispersion states, shape characteristics and particle size distribution characteristics, and sea-island structure characteristics shown in Tables 1 to 3 by arbitrarily adjusting the coefficient of variation of the toner particle size and particle size distribution. Comparative colored particles 1 to 4 were obtained.
[0298]
[Table 1]

[0299]
[Table 2]

[0300]
[Table 3]

[0301]
To each of the colored particles 1 to 13 and the comparative colored particles 1 to 4 obtained as described above, 0.8 part by weight of hydrophobic silica and 1.0 part by weight of hydrophobic titanium oxide are added, and 10 l of Henschel is added. The peripheral speed of the rotating blades of the mixer was set to 30 m / s and mixed for 25 minutes. In addition, the shape and particle size of these colored particles are not changed by the addition of an external additive.
[0302]
Carrier manufacturing
Manufacture of ferrite core material
18 mol% of MnO, 4 mol% of MgO, Fe₂O_Three78 mol% was pulverized, mixed and dried in a wet ball mill for 2 hours, and then temporarily calcined by maintaining at 900 ° C. for 2 hours, and this was pulverized in a ball mill for 3 hours to form a slurry. Dispersant and binder are added, granulated and dried with a spray dryer, followed by main firing at 1200 ° C. for 3 hours, resistance value 4.3 × 10⁸Ω · cm ferrite core material particles were obtained.
[0303]
Manufacture of coating resin
First, a cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5 /) was prepared by an emulsion polymerization method in which the concentration in an aqueous medium using sodium benzenesulfonate having an alkyl group having 12 carbon atoms as a surfactant was 0.3% by mass. 5), a volume average primary particle size of 0.1 μmm, a weight average molecular weight (Mw) of 200,000, a number average molecular weight (Mn) of 91,000, Mw / Mn = 2.2, a softening point temperature. Resin fine particles having (Tsp) 230 ° C. and glass transition temperature (Tg) 110 ° C. were obtained. The resin fine particles azeotroped with water in the emulsified state, and the residual monomer amount was 510 ppm.
[0304]
Next, 100 parts by mass of ferrite core material particles and 2 parts by mass of the resin fine particles are put into a high-speed agitator / mixer equipped with stirring blades, stirred and mixed at 120 ° C. for 30 minutes, and the mechanical impact force is applied to the volume. A resin-coated carrier having an average particle size of 61 μm was obtained.
[0305]
Production of developer
Each of colored particles 1 to 13 to which an external additive has been added and comparative colored particles 1 to 4 are mixed with a carrier to prepare a developer having a toner concentration of 6% by mass. Examples 1 to 13 and comparison It was set as Examples 1-4.
[0306]
Manufacture of photoreceptor P1
The following coating solution was applied onto a cylindrical conductive support having a length of 380 mm and a diameter of 60 mm to produce a photoreceptor P1.
<Underlayer>
Titanium chelate compound (TC-750, manufactured by Matsumoto Pharmaceutical) 30g
Silane coupling agent (KBM-503, Shin-Etsu Chemical Co., Ltd.) 17g
150 ml of 2-propanol
It apply | coated so that it might become a film thickness of 0.5 micrometer on the cylindrical conductive support body using the said coating liquid.
[0307]
<Charge generation layer>
Y-type titanyl phthalocyanine (titanyl phthalocyanine having a maximum peak at 27.2 ° with a Bragg angle 2θ (± 0.2 °) as measured by Cu-Kα characteristic X-ray diffraction spectrum) 60 g
700 g of silicone-modified butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co., Ltd.)
2-butanone 2000ml
Were mixed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the undercoat layer by a dip coating method to form a charge generation layer having a thickness of 0.2 μm.
[0308]
<Charge transport layer>
Charge transport material N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine 225 g
Polycarbonate (viscosity average molecular weight 30,000) 300g
Antioxidant (Exemplary Compound 1-3) 6 g
Dichloromethane 2000ml
Were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 20 μm.
[0309]
<Protective layer>
150g of methyltrimethoxysilane
Dimethyldimethoxysilane 30g
Reactive charge transport compound (Exemplary Compound B-1) 15 g
Polyvinylidene fluoride particles (volume average particle size 0.2 μm) 10 g
Antioxidant (Exemplary Compound 2-1) 0.75 g
2-propanol 75g
3% acetic acid 5g
Were mixed to prepare a coating solution for the resin layer. A 2 μm-thick resin layer is formed on the charge transport layer on the charge transport layer by using a circular amount-regulating coating apparatus, and heat-cured at 120 ° C. for 1 hour to form a siloxane resin layer. Produced.
[0310]
[Chemical 3]

[0311]
As an evaluation machine, a digital copying machine (having corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, and cleaning blade) having the image forming process shown in FIG. 6, a photoconductor (P1) and each developer And evaluated. The digital copying machine was evaluated under the following conditions.
[0312]
Charging conditions
Charger: Scorotron charger, initial charge potential of -750V
Exposure conditions
Set the exposure amount so that the potential of the exposed area is -50V.
Development conditions
DC bias; -550V
Transfer pole; corona charging method
[0313]
In addition, as a fixing device, a heating roller using iron as a core metal and having a surface roughness Ra of 0.8 μm coated with PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having a thickness of 25 μm. Was used, and an iron cored bar was used as a pressure roller, and a pressure roller having a surface roughness Ra of 0.8 μm, in which a PFA tube having a thickness of 120 μm was coated on HTV silicone rubber, was used. The nip width is 3.8 mm, and the linear velocity is 420 mm / sec.
[0314]
The cleaning mechanism for the fixing device and the silicon oil supply mechanism are not installed. The fixing temperature was controlled by the surface temperature of the heating roller, and was set to 165 ° C.
[0315]
Copying conditions were continuous 500,000 copies in a low-temperature and low-humidity environment (10 ° C., 20% RH). The life, halftone uniformity, and occurrence of character collapse were evaluated.
[0316]
<Non-visual offset>
10 g x 50 mm, 5 mm thick felt pad 50 g / cm²(5 × 10^-FivePa was applied with a load of Pa), and the smear after printing 10,000 sheets was observed.
Evaluation criteria
: There is no stain on the felt pad.
: Very slight dirt is generated on the felt pad (no problem in practical use).
X: Dirt is generated on the felt pad image (there is a problem in practical use).
[0317]
<Winding during high-speed fixing>
The line speed setting was changed from 420 mm / sec to 840 mm / sec while keeping the temperature setting of the heat roller at 165 ° C., a solid image was copied after printing 20,000 sheets, and the wrapping property and the fixing rate were evaluated. .
Evaluation criteria
: No paper jam occurs due to poor fixing separation, and no fixing separation claw mark is observed.
: No paper jam occurred due to poor fixing separation, but some fixing separation claw marks were observed (no problem in practical use).
×: Paper jam occurs due to poor fixing separation (practical problem).
The fixing rate was measured using A4 size plain paper (weighing 65 g / m²)It was used.
[0318]
<Fixing roller life>
Evaluation was based on the number of image stains caused by scratches on the fixing roller.
[0319]
<Cleaning performance>
Evaluation was made based on the number of images determined as image smearing because the toner slipped on the photosensitive member from the cleaning device on the white background of the image. The following items ◎ and ○ were accepted.
Evaluation criteria
: Not generated up to 500,000 sheets.
: Generated at 400,000 to 500,000 sheets.
X: Occurs in less than 400,000 sheets.
[0320]
<Dirt during bookbinding>
Double-sided copying was performed on 64 g / m 2 of plain paper to make 100 booklets per book, and then the stain on the white background was observed when turning 20 times.
Rank A: There is no stain on the image.
Rank B: Slight dirt was confirmed on the image, but it was at a level where there was no practical problem at all.
Rank C: Slight dirt was confirmed on the image, but there was no practical problem.
Rank D: The image has dirt and is not suitable for practical use.
Evaluation ranks A, B, and C were accepted, and D was rejected.
[0321]
<Photoconductor filming>
The presence or absence of filming was determined by visual observation of the surface of the photoreceptor after the above-mentioned continuous 500,000 copies.
[0322]
<Life of photoconductor>
Evaluation was made by the number of sheets when the fog density (relative density of the non-image area with respect to the transfer paper) when the exposure amount was maximized exceeded 0.01. The fog density was measured with a reflection density measuring device PDA-65 (manufactured by Konica Corporation).
[0323]
<Uniformity of halftone>
The uniformity of the halftone image accompanying the transferability variation such as photoconductor filming was evaluated. The evaluation criteria are as follows.
Rank A: A uniform image without unevenness.
Rank B: There are streaky thin irregularities, but there is no practical problem.
Rank C: There are several stripe-like thin irregularities, but there is no practical problem.
Rank D: Several or more streaky irregularities exist, and there is a problem in practical use.
[0324]
<Crushed characters>
3-point and 5-point character images were formed and evaluated according to the following evaluation criteria.
A: 3 points and 5 points are clear, easily readable and practically no problem.
◯: Some characters are illegible in 3 points, but 5 points are clear and easily readable, and there is no practical problem.
X: Most characters are unreadable at 3 points, and 5 points are practically problematic in a state where some or all of them are unreadable.
The results for the above evaluation items are shown in Table 4.
[0325]
[Table 4]

[0326]
As apparent from the results in Table 4, the toner for developing an electrostatic charge image of the present invention can suppress the occurrence of non-visual offset and the like, and it is not necessary to replace the fixing device for a long period of 300,000 sheets or more. It was confirmed that continuous use was possible. In addition, it is possible to obtain results that can significantly extend the life of the photosensitive member, and have a performance far superior to that of the conventional electrostatic image developing toner used as a comparative sample. Was confirmed.
[0327]
【The invention's effect】
According to the toner for developing an electrostatic charge image of the present invention, it is possible to suppress the occurrence of non-visual offset by enabling effective exudation of the crystalline substance in the toner during the fixing step, and from the low speed machine to the high speed machine. It has become possible to eliminate the oil application mechanism from the fixing device until it reaches the end, greatly extending the life of the fixing roller and preventing dirt from adhering to the paper during bookbinding. Further, as a result of suppressing the occurrence of photoconductor filming and the like, it is possible to extend the life of the photoconductor and to provide an image with excellent sharpness over a long period of time.
[0328]
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating toner particles having a sea-island structure according to the present invention, and a schematic diagram in which the distance between the nearest walls between the islands in the toner particles according to the present invention is indicated by arrows (← →) (island B is omitted). is there.
FIG. 2 is a schematic diagram in which toner particles having a sea-island structure according to the present invention are divided by Voronoi polygons.
FIG. 3 is a stirring device used for obtaining colorant particles contained in toner particles having a sea-island structure according to the present invention.
FIG. 4 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus applied to the present invention.
FIG. 5 is a perspective configuration diagram of a toner recycling member.
FIG. 6 is a schematic view of a digital image forming apparatus applied to the present invention.
FIG. 7 is a schematic sectional view of a fixing device applied to the present invention.
FIG. 8 is a schematic diagram illustrating a toner having no corners or corners.
[Explanation of symbols]
1 Semiconductor laser light source
2 Polygon mirror
3 fθ lens
4 Photosensitive drum
5 Charger
6 Developer
7 Transfer device
8 Transfer paper
9 Separator
10 Fixing device
11 Cleaning device
12 Pre-charge exposure
13 Cleaning blade
14 Toner recycling pipe
15 Recycling pipe receptacle
71 Heating roller
72 Pressure roller
75 Heating member
81 Core of heating roller
82 Heating roller coating layer
101 screen
102 rotor
103 Pressurized vacuum attachment
104 Preliminary dispersion outlet
105 Dispersion outlet
106 Temperature sensor
107 Cooling jacket
108 Cooling coil
111 Dispersion container
112 Stirrer
113 Stirring shaft

Claims (19)

In an electrostatic charge image developing toner containing at least a resin, a colorant, and a crystalline substance, the toner has an endothermic peak at 60 to 110 ° C. in a DSC curve, and an endothermic amount is 4 to 30 J / g. The toner contains a crystalline substance and is obtained by salting out / fusion-bonding resin particles and colorant particles obtained by a multistage polymerization method. The toner particles have a sea-island structure, and are contained in the toner particles. The average distance between the nearest walls between the islands is 100 to 1060 nm, and the number of the islands with the distance between the nearest walls is 1300 nm or more is 10% by number or less of the whole island. A toner for developing an electrostatic charge image. In an electrostatic charge image developing toner containing at least a resin, a colorant, and a crystalline substance, the toner has an endothermic peak at 60 to 110 ° C. in a DSC curve, and an endothermic amount is 4 to 30 J / g. The toner contains a crystalline substance and is obtained by salting out / fusing resin particles obtained by a multistage polymerization method and colorant particles, and the toner particles have a sea-island structure. Among the islands made of crystalline material, the average distance between the nearest walls between the islands is 260 to 820 nm, and the number of the islands whose distance between the nearest walls is 1300 nm or more is 4% by number of the whole islands. A toner for developing an electrostatic charge image.   3. The toner for developing an electrostatic charge image according to claim 1, wherein the toner particles have a sea-island structure, and the toner particles have 98% or more toner particles on which no islands are exposed. Toner for electrostatic image development. The toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein the toner particles have a sea-island structure, and bisect between the centroids of adjacent islands in the sea-island structure. An electrostatic charge image development characterized in that the average value of the area of the Voronoi polygon formed by the line is 20,000 to 120,000 nm ² and the coefficient of variation of the area of the Voronoi polygon is 25% or less. Toner. The toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein the toner particles have a sea-island structure, and bisect between vertical centers of adjacent islands in the sea-island structure. The average value of the area of the Voronoi polygon formed by the line is 40,000 to 100,000 nm ² and the coefficient of variation of the area of the Voronoi polygon is 20% or less. Toner. The toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein the toner particles have a sea-island structure, and bisect between the centroids of adjacent islands in the sea-island structure. An electrostatic charge comprising 3 to 20% of islands having an average area of Voronoi polygons formed by lines of 20,000 to 120,000 nm ² and an area of 160,000 nm ² or more. Toner for image development.   The toner for developing an electrostatic charge image according to claim 1, wherein the toner particles have a sea-island structure and exist outside a circle having a radius of 1000 nm centered on a center of gravity in a cross section of the toner particles. The average value of the area of the Voronoi polygon formed by the vertical bisector between the centroids of the islands is the value of the Voronoi polygon formed by the vertical bisector between the centroids of the islands existing inside the circle. An electrostatic charge image developing toner having a larger area average value. The electrostatic charge image developing toner according to claim 1, wherein the toner particles have a sea-island structure, and a perpendicular bisector between the centers of gravity of adjacent islands in the sea-island structure. Among the Voronoi polygons formed by the above method, there are 5 to 30 islands having a Voronoi polygon area of 160,000 nm ² or more with respect to the Voronoi polygon existing in contact with the outer periphery of the toner. Toner for electrostatic image development.   9. The electrostatic charge image developing toner according to claim 1, wherein the toner particles have a sea-island structure, and the islands are configured by islands having different luminances. Toner for electrostatic image development.   The toner for developing an electrostatic charge image according to any one of claims 1 to 9, wherein the toner has a number variation coefficient in a number particle size distribution of 27% or less and a variation coefficient of a shape factor of 16% or less. A toner for developing an electrostatic charge image.   The toner for developing an electrostatic charge image according to any one of claims 1 to 9, wherein the toner has a ratio of toner particles having a shape factor in the range of 1.2 to 1.6 of 65% by number or more. An electrostatic charge image developing toner having a variation coefficient of shape factor of 16% or less.   The electrostatic image developing toner according to claim 1, wherein the toner has a number average particle diameter of 3 to 9 μm.   13. The electrostatic image developing toner according to claim 1, wherein the toner has a natural logarithm lnD on the horizontal axis when the particle diameter of the toner particles is D (μm). The relative frequency (m1) of the toner particles included in the most frequent class in the histogram showing the number-based particle size distribution with the axis divided into a plurality of classes at intervals of 0.23 and the next most frequent class after the most frequent class A toner for developing an electrostatic charge image, wherein the sum (M) of the relative power (m2) of the toner particles contained is 70% or more.   The toner for developing an electrostatic charge image according to any one of claims 1 to 13, wherein the toner is subjected to a step of polymerizing the polymerizable monomer after dissolving the crystalline substance in at least the polymerizable monomer. A toner for developing an electrostatic charge image, which is obtained by salting out / fusion-bonding the formed composite resin fine particles and colored particles containing a colorant.   The toner for developing an electrostatic charge image according to any one of claims 1 to 14, wherein the toner is obtained by salting out / fusion-bonding at least composite resin particles obtained by a multistage polymerization method and colorant particles. An electrostatic charge image developing toner,   The electrostatic image developing toner according to any one of claims 1 to 15, wherein the toner is formed by fusing resin particles on a surface of colored particles containing a resin and a colorant by a salting-out / fusing method. An electrostatic charge image developing toner obtained by forming a resin phase.   17. A method for producing a toner for developing an electrostatic charge image, comprising producing the toner for developing an electrostatic charge image according to any one of claims 14 to 16.   17. An image forming method comprising the steps of: visualizing an electrostatic latent image formed on a photoconductor; transferring the visible image onto a recording medium; and heat-fixing the visible image. An image forming method, wherein the electrostatic charge image developing toner according to claim 1 is used and heat fixing at a linear speed of 230 to 900 mm / sec.   19. The image forming method according to claim 18, further comprising the steps of: visualizing the electrostatic latent image formed on the photoconductor; transferring the visible image onto a recording medium; and heat-fixing the image. An image forming method comprising forming an electrostatic latent image by performing exposure.

Images