JP3882526B2 - Heat fixing toner and image forming method - Google Patents

Description

【００９６】
【化２】

【００９７】
〈離型剤の含有割合〉
本発明に係るトナーを構成する離型剤の含有割合としては、通常１〜３０質量％であり、好ましくは２〜２０質量％、更に好ましくは３〜１５質量％である。
【００９８】
〈複合樹脂粒子における離型剤の含有領域〉
本発明に係る複合樹脂粒子を用いたトナーにおいて、これを構成する複合樹脂粒子における離型剤は、当該複合樹脂粒子の最外層以外の領域（中心部または中間層）に含有されるのがよい。
【００９９】
これにより、複合樹脂粒子の最外層には、粒子間接着力を低下させる離型剤が含有されていないので、当該複合樹脂粒子同士は、塩析／融着工程において強固に接着し、破砕強度の高い融着粒子（請求項４に係る本発明のトナーを構成するトナー粒子）が形成される。
【０１００】
又、塩析により融着をおこさせるために使用される凝集剤としては特に限定されるものではないが、金属塩から選択されるものが好適に使用される。具体的には、一価の金属として例えばナトリウム、カリウム、リチウム等のアルカリ金属の塩、二価の金属として例えばカルシウム、マグネシウム等のアルカリ土類の金属塩、マンガン、銅等の二価の金属の塩、鉄、アルミニウム等の三価の金属の塩等が挙げられ、具体的な塩としては、塩化ナトリウム、塩化カリウム、塩化リチウム、塩化カルシウム、塩化亜鉛、硫酸銅、硫酸マグネシウム、硫酸マンガン等を挙げることができる。これらは組み合わせて使用してもよい。
【０１０１】
これらの凝集剤は臨界凝集濃度以上添加することが好ましい。この臨界凝集濃度とは、水性分散物の安定性に関する指標であり、凝集剤を添加して凝集が発生する濃度を示すものである。この臨界凝集濃度は、乳化された成分および分散剤自体によって大きく変化するものである。例えば、岡村誠三他著「高分子化学１７、６０１（１９６０）高分子学会編」等に記述されており、詳細な臨界凝集濃度を求めることができる。また、別な手法として、目的とする粒子分散液に所望の塩を濃度を変えて添加し、その分散液のζ（ゼータ）電位を測定し、この値が変化する塩濃度を臨界凝集濃度として求めることもできる。
【０１０２】
本発明の凝集剤の添加量は、臨界凝集濃度以上であればよいが、好ましくは臨界凝集濃度の１．２倍以上、さらに好ましくは、１．５倍以上添加することがよい。
【０１０３】
無限溶解する溶媒とは、すなわち水に対して無限溶解する溶媒を示し、この溶媒は、本発明においては形成された樹脂を溶解させないものが選択される。具体的には、メタノール、エタノール、プロパノール、イソプロパノール、メトキシエタノール、ブトキシエタノール等のアルコール類、アセトニトリル等のニトリル類、ジオキサン等のエーテル類を挙げることができる。特に、エタノール、プロパノール、イソプロパノールが好ましい。
【０１０４】
この無限溶解する溶媒の添加量は、凝集剤を添加した重合体含有分散液に対して１〜１００体積％が好ましい。
【０１０５】
なお、形状を均一化させるためには、着色粒子を調製し、濾過した後に粒子に対して１０質量％以上の水が存在したスラリーを流動乾燥させることが好ましいが、この際、特に重合体中に極性基を有するものが好ましい。この理由としては、極性基が存在している重合体に対して、存在している水が多少膨潤する効果を発揮するために、形状の均一化が特に図られやすいものと考えられる。
【０１０６】
本発明のトナーは少なくとも樹脂と着色剤を含有するものであるが、必要に応じて定着性改良剤である離型剤や荷電制御剤等を含有することもできる。さらに、上記樹脂と着色剤を主成分とするトナー粒子に対して無機微粒子や有機微粒子等で構成される外添剤を添加したものであってもよい。
【０１０７】
〈着色剤〉
本発明のトナーに使用する着色剤としてはカーボンブラック、磁性体、染料、顔料等を任意に使用することができ、カーボンブラックとしてはチャンネルブラック、ファーネスブラック、アセチレンブラック、サーマルブラック、ランプブラック等が使用される。磁性体としては鉄、ニッケル、コバルト等の強磁性金属、これらの金属を含む合金、フェライト、マグネタイト等の強磁性金属の化合物、強磁性金属を含まないが熱処理する事により強磁性を示す合金、例えばマンガン−銅−アルミニウム、マンガン−銅−錫等のホイスラー合金と呼ばれる種類の合金、二酸化クロム等を用いる事ができる。
【０１０８】
染料としてはＣ．Ｉ．ソルベントレッド１、同４９、同５２、同５８、同６３、同１１１、同１２２、Ｃ．Ｉ．ソルベントイエロー１９、同４４、同７７、同７９、同８１、同８２、同９３、同９８、同１０３、同１０４、同１１２、同１６２、Ｃ．Ｉ．ソルベントブルー２５、同３６、同６０、同７０、同９３、同９５等を用いる事ができ、またこれらの混合物も用いる事ができる。顔料としてはＣ．Ｉ．ピグメントレッド５、同４８：１、同５３：１、同５７：１、同１２２、同１３９、同１４４、同１４９、同１６６、同１７７、同１７８、同２２２、Ｃ．Ｉ．ピグメントオレンジ３１、同４３、Ｃ．Ｉ．ピグメントイエロー１４、同１７、同９３、同９４、同１３８、Ｃ．Ｉ．ピグメントグリーン７、Ｃ．Ｉ．ピグメントブルー１５：３、同６０等を用いる事ができ、これらの混合物も用いる事ができる。数平均一次粒子径は種類により多様であるが、概ね１０〜２００ｎｍ程度が好ましい。
【０１０９】
着色剤の添加方法としては、乳化重合法で調製した重合体粒子を、凝集剤を添加することで凝集させる段階で添加し重合体を着色する方法や、単量体を重合させる段階で着色剤を添加し、重合し、着色粒子とする方法等を使用することができる。なお、着色剤は重合体を調製する段階で添加する場合はラジカル重合性を阻害しない様に表面をカップリング剤等で処理して使用することが好ましい。
【０１１０】
さらに、定着性改良剤としての低分子量ポリプロピレン（数平均分子量＝１５００〜９０００）や低分子量ポリエチレン等を添加してもよい。
【０１１１】
荷電制御剤も同様に種々の公知のもので、且つ水中に分散することができるものを使用することができる。具体的には、ニグロシン系染料、ナフテン酸または高級脂肪酸の金属塩、アルコキシル化アミン、第４級アンモニウム塩化合物、アゾ系金属錯体、サリチル酸金属塩あるいはその金属錯体等が挙げられる。なお、これら荷電制御剤や定着性改良剤の粒子は、分散した状態で数平均一次粒子径が１０〜５００ｎｍ程度とすることが好ましい。前述した重合性単量体中に着色剤などのトナー構成成分を分散あるいは溶解したものを水系媒体中に懸濁し、ついで重合せしめてトナーを得る懸濁重合法トナーでは、重合反応を行う反応容器中での媒体の流れを制御することによりトナー粒子の形状を制御することができる。この様な方法によるいわゆる懸濁重合法トナーにおいても本発明は有用である。
【０１１２】
更に結着樹脂を別途調製した後、着色剤などのトナー構成成分と共に混練し、粉砕、シリカ等の外添剤と混合分散し、粉砕トナーを得る等の方法によって得られたいわゆる粉砕トナーにおいても同様に有用である。粉砕トナー粒子の製造法は、従来から用いられる各種トナー製造方法が適用できるが、例えば一般的な例として、まず樹脂、着色剤、ワックス、帯電制御剤等を混合機で均一に分散混合し、次いで混合物を密閉式ニーダー、或いは１軸または２軸の押出機等で溶融混練し、冷却後、クラッシャー、ハンマーミル等で粗粉砕し、ジェットミル、高速ローター回転式ミル等で微粉砕し、風力分級機（例えば、慣性分級方式のエルボジェット、遠心力分級方式のミクロプレックス、ＤＳセパレーターなど）等で分級する事によって製造してもよい。トナーの平均粒径は、３〜２０μｍが好適である。上記の溶融混練工程において、最終的トナーとしての帯電性能・定着性能を損なわないような範囲内において、本発明の微量成分を調整することも好ましい。本発明者らの検討においては、振れはあるものの溶融混練工程によって本発明の微量成分は、２〜４割程度減少する。
【０１１３】
本発明の熱定着用トナーにおいては、高い定着性を得るために形状係数の変動係数が１６％以下であり、個数粒度分布における個数変動係数が２７％以下であることが好ましい。すなわち、トナー自体の形状の分布を均一化することにより、定着時の熱伝導、熱変形を均一にし定着不良の発生を防止することができる。
【０１１４】
又、本発明者等が更に検討した結果、角がないトナー粒子ではその表面の平滑性により、形状のバラツキが多少大きくても、同様の効果を発揮する。すなわち、角がないトナー粒子が５０個数％以上であるトナーを使用することが好ましい。
【０１１５】
さらに、本発明者等の検討の結果、特定の形状についてその形状を揃えた場合にも、トナーの熱変形を均一化することができ、同様の効果を発揮することを見出した。すなわち、形状係数が１．０〜１．６、好ましくは１．２〜１．６の範囲にあるトナー粒子が６５個数％以上であるトナーを使用することが好ましい。
【０１１６】
本発明においてトナーの形状係数は、下記式により示されるものであり、トナー粒子の丸さの度合いを示す。
【０１１７】
形状係数＝（（最大径／２）²×π）／投影面積
ここに、最大径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。また、投影面積とは、トナー粒子の平面上への投影像の面積をいう。
【０１１８】
本発明では、この形状係数は、走査型電子顕微鏡により２０００倍にトナー粒子を拡大した写真を撮影し、ついでこの写真に基づいて「ＳＣＡＮＮＩＮＧ ＩＭＡＧＥ ＡＮＡＬＹＺＥＲ」（日本電子社製）を使用して写真画像の解析を行うことにより測定した。この際、１００個のトナー粒子を使用して本発明の形状係数を上記算出式にて測定したものである。
【０１１９】
この形状係数を制御する方法は特に限定されるものではない。例えばトナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し旋回流を付与する方法等により、形状係数を１．０〜１．６、または１．２〜１．６にしたトナーを調製し、これを通常のトナー中へ本発明の範囲内になるように添加して調整する方法がある。また、いわゆる重合法トナーを調製する段階で全体の形状を制御し、形状係数を１．０〜１．６、または１．２〜１．６に調整したトナーを調製する方法がある。
【０１２０】
上記方法の中では重合法トナーが製造方法として簡便である点と、粉砕トナーに比較して表面の均一性に優れる点等で好ましい。
【０１２１】
本発明において、トナーの形状係数の変動係数は下記式から算出される。
変動係数＝（Ｓ／Ｋ）×１００（％）
式中、Ｓは１００個のトナー粒子の形状係数の標準偏差を示し、Ｋは形状係数の平均値を示す。
【０１２２】
この形状係数の変動係数は１６％以下であり、好ましくは１４％以下である。形状係数の変動係数が１６％以下であることにより、転写されたトナー層の空隙が減少して定着性が向上し、オフセットが発生しにくくなる。また、帯電量分布がシャープとなり、画質が向上する。
【０１２３】
このトナーの形状係数および形状係数の変動係数を、極めてロットのバラツキなく均一に制御するために、樹脂粒子（重合体粒子）を重合、融着、形状制御させる工程において、形成されつつあるトナー粒子（着色粒子）の特性をモニタリングしながら適正な工程終了時期を決めてもよい。
【０１２４】
モニタリングするとは、インラインに測定装置を組み込みその測定結果に基づいて、工程条件の制御をするという意味である。すなわち、形状などの測定をインラインに組み込んで、例えば樹脂粒子を水系媒体中で会合あるいは融着させることで形成する重合法トナーでは、融着などの工程で逐次サンプリングを実施しながら形状や粒径を測定し、所望の形状になった時点で反応を停止する。
【０１２５】
モニタリング方法としては、特に限定されるものではないが、フロー式粒子像分析装置ＦＰＩＡ−２０００（シスメック社製）を使用することができる。本装置は試料液を通過させつつリアルタイムで画像処理を行うことで形状をモニタリングできるため好適である。すなわち、反応場よりポンプなどを使用し、常時モニターし、形状などを測定することを行い、所望の形状などになった時点で反応を停止するものである。
【０１２６】
本発明において、トナーの個数粒度分布および個数変動係数はコールターカウンターＴＡ−IIあるいはコールターマルチサイザー（コールター社製）で測定されるものである。本発明においてはコールターマルチサイザーを用い、粒度分布を出力するインターフェース（日科機社製）、パーソナルコンピューターを接続して使用した。前記コールターマルチサイザーにおいて使用するアパーチャーとしては１００μｍのものを用いて、２μｍ以上のトナーの体積、個数を測定して粒度分布および平均粒径を算出した。個数粒度分布とは、粒子径に対するトナー粒子の相対度数を表すものであり、個数平均粒径とは、個数粒度分布におけるメジアン径を表すものである。
【０１２７】
トナーの個数粒度分布における個数変動係数は下記式から算出される。
個数変動係数＝（Ｓ／Ｄｎ）×１００（％）
式中、Ｓは個数粒度分布における標準偏差を示し、Ｄｎは個数平均粒径（μｍ）を示す。
【０１２８】
本発明において、トナーの個数変動係数は２７％以下が好ましく、更に好ましくは２５％以下である。個数変動係数が２７％以下であることにより、転写されたトナー層の空隙が減少して定着性が向上し、オフセットが発生しにくくなる。また、帯電量分布がシャープとなり、転写効率が高くなって画質が向上する。
【０１２９】
本発明において個数変動係数を制御する方法は特に限定されるものではない。例えば、トナー粒子を風力により分級する方法も使用できるが、個数変動係数をより小さくするためには液中での分級が効果的である。この液中で分級する方法としては、遠心分離機を用い、回転数を制御してトナー粒子径の違いにより生じる沈降速度差に応じてトナー粒子を分別回収し調製する方法がある。
【０１３０】
特に懸濁重合法によりトナーを製造する場合、個数粒度分布における個数変動係数を２７％以下とするためには分級操作が必須である。懸濁重合法では、重合前に重合性単量体を系媒体中にトナーとしての所望の大きさの油滴に分散させることが必要である。すなわち、重合性単量体の大きな油滴に対して、ホモミキサーやホモジナイザーなどによる機械的な剪断を繰り返して、トナー粒子程度の大きさまで油滴を小さくすることとなるが、このような機械的な剪断による方法では、得られる油滴の個数粒度分布は広いものとなり、従って、これを重合してなるトナーの粒度分布も広いものとなる。このために分級操作が必須となる。
【０１３１】
本発明において、角がないトナー粒子とは、電荷の集中するような突部またはストレスにより摩耗しやすいような突部を実質的に有しないトナー粒子をいい、具体的には以下のトナー粒子を角がないトナー粒子という。すなわち、図１（ａ）、（ｂ）、（ｃ）に示すように、トナー粒子の長径をＬ、Ｌ／１０を半径Ｒとする円で、トナー粒子周囲線に対し１点で内側に接しつつ内側をころがした場合に、全く円がトナーの外側に実質的にはみださない場合を角がないトナー粒子という。実質的にはみ出さない場合とは、はみ出す円が存在する突起が１箇所以下をいう。また、トナー粒子の長径とは、トナー粒子の平面上への投影像を２本の平行線ではさんだとき、その平行線の間隔が最大となる粒子の幅をいう。
【０１３２】
角がないトナーの測定は次のようにして行った。先ず、走査型電子顕微鏡によりトナー粒子を拡大した写真を撮影し、さらに拡大して１５，０００倍の写真像を得る。次いでこの写真像について前記の角の有無を測定する。この測定を１００個のトナー粒子について行った。
【０１３３】
本発明のトナーにおいて、角がないトナー粒子の割合は５０個数％以上であることが好ましく、更に好ましくは７０個数％以上である。角がないトナー粒子の割合が５０個数％以上であることにより、現像剤搬送部材などとのストレスにより微細な粒子の発生などがおこりにくくなり、いわゆる現像剤搬送部材表面に対する付着性の過度なトナーの存在を防止することができるとともに、現像剤搬送部材に対する汚染を抑制することができ、帯電量もシャープにすることができる。また、摩耗、破断しやすいトナー粒子および電荷の集中する部分を有するトナー粒子が減少することとなり、帯電量分布がシャープとなって、帯電性も安定し、良好な画質を長期にわたって形成できる。
【０１３４】
角がないトナーを得る方法は特に限定されるものではない。例えば、形状係数を制御する方法として前述したように、トナー粒子を熱気流中に噴霧する方法、またはトナー粒子を気相中において衝撃力による機械的エネルギーを繰り返して付与する方法、あるいはトナーを溶解しない溶媒中に添加し、旋回流を付与することによって得ることができる。
【０１３５】
又、樹脂粒子を会合あるいは融着させることで形成する重合法トナーにおいては、融着停止段階では融着粒子表面には多くの凹凸があり、表面は平滑でないが、形状制御工程での温度、撹拌翼の回転数および撹拌時間等の条件を適当なものとすることによって、角がないトナーが得られる。これらの条件は、樹脂粒子の物性により変わるものであるが、例えば、樹脂粒子のガラス転移点温度以上で、より高回転数とすることにより、表面は滑らかとなり、角がないトナーが形成できる。
【０１３６】
本発明のトナーの粒径は、個数平均粒径で２〜８μｍのものが好ましい。この粒径は、重合法によりトナー粒子を形成させる場合には、凝集剤の濃度や有機溶媒の添加量、または融着時間、さらには重合体自体の組成によって制御することができる。
【０１３７】
個数平均粒径が２〜８μｍであることにより、定着工程において、現像剤搬送部材に対する付着性の過度なトナーや付着力の低いトナー等の存在を少なくすることができ、現像性を長期に亘って安定化することができるとともに、転写効率が高くなってハーフトーンの画質が向上し、細線やドット等の画質が向上する。
【０１３８】
本発明のトナーとしては、トナー粒子の粒径をＤ（μｍ）とするとき、自然対数ｌｎＤを横軸にとり、この横軸を０．２３間隔で複数の階級に分けた個数基準の粒度分布を示すヒストグラムにおいて、最頻階級に含まれるトナー粒子の相対度数（ｍ１）と、前記最頻階級の次に頻度の高い階級に含まれるトナー粒子の相対度数（ｍ２）との和（Ｍ）が７０％以上であるトナーであることが好ましい。相対度数（ｍ１）と相対度数（ｍ２）との和（Ｍ）が７０％以上であることにより、トナー粒子の粒度分布の分散が狭くなるので、当該トナーを画像形成工程に用いることにより選択現像の発生を確実に抑制することができる。
【０１３９】
本発明において、前記の個数基準の粒度分布を示すヒストグラムは、自然対数ｌｎＤ（Ｄ：個々のトナー粒子の粒径）を０．２３間隔で複数の階級（０〜０．２３：０．２３〜０．４６：０．４６〜０．６９：０．６９〜０．９２：０．９２〜１．１５：１．１５〜１．３８：１．３８〜１．６１：１．６１〜１．８４：１．８４〜２．０７：２．０７〜２．３０：２．３０〜２．５３：２．５３〜２．７６・・・）に分けた個数基準の粒度分布を示すヒストグラムであり、このヒストグラムは、下記の条件に従って、コールターマルチサイザーにより測定されたサンプルの粒径データを、Ｉ／Ｏユニットを介してコンピュータに転送し、当該コンピュータにおいて、粒度分布分析プログラムにより作成されたものである。
【０１４０】
測定条件
（１）アパーチャー：１００μｍ
（２）サンプル調製法：電解液（ＩＳＯＴＯＮ Ｒ−１１（コールターサイエンティフィックジャパン社製））５０〜１００ｍｌに界面活性剤（中性洗剤）を適量加えて撹拌し、これに測定試料１０〜２０ｍｇを加える。この系を超音波分散機にて１分間分散処理することにより調製する。
【０１４１】
次に、本発明に係わる数値について、従来知られているトナーの数値を説明する。この数値は製造方法により異なるものである。
【０１４２】
粉砕法トナーの場合、形状係数が１．２〜１．６であるトナー粒子の割合は６０個数％程度である。このものの形状係数の変動係数は２０％程度である。また、粉砕法では破砕を繰り返しながら粒径を小さくするために、トナー粒子に角部分が多くなり、角がないトナー粒子の割合は３０個数％以下である。従って、形状を揃えて、角部分がなく、丸みのあるトナーを得ようとする場合には、形状係数を制御する方法として前記した様に熱等により球形化する処理が必要となる。また、個数粒度分布における個数変動係数は、粉砕後の分級操作が１回である場合には、３０％程度であり、個数変動係数を２７％以下とするためには、さらに分級操作を繰り返す必要がある。
【０１４３】
懸濁重合法によるトナーの場合、従来は層流中において重合されるため、ほぼ真球状のトナー粒子が得られ、例えば特開昭５６−１３０７６２号公報に記載されたトナーでは、形状係数が１．２〜１．６であるトナー粒子の割合が２０個数％程度となり、また形状係数の変動係数も１８％程度となり、更に角がないトナー粒子の割合も８５個数％程度となる。また、個数粒度分布における個数変動係数を制御する方法に前記した様に、重合性単量体の大きな油滴に対して、機械的な剪断を繰り返して、トナー粒子程度の大きさまで油滴を小さくするため、油滴径の分布は広くなり、従って得られるトナーの粒度分布は広く、個数変動係数は３２％程度と大きいものであり、個数変動係数を小さくするためには上記公報記載の技術に基づいてトナーを作製するのであれば分級操作が必要である。
【０１４４】
樹脂粒子を会合あるいは融着させることで形成する重合法トナーにおいては、例えば特開昭６３−１８６２５３号公報に記載されたトナーでは、形状係数が１．２〜１．６であるトナー粒子の割合は６０個数％程度であり、また形状係数の変動係数は１８％程度であり、更に角がないトナー粒子の割合も４４個数％程度である。さらに、トナーの粒度分布は広く、個数変動係数は３０％であり、個数変動係数を小さくするためには分級操作が必要である。
【０１４５】
〈外添剤〉
本発明においては、着色粒子に流動性を付与する観点から従来公知の無機微粒子および有機微粒子を使用することができる。かかる無機微粒子を構成する化合物としては、各種の無機酸化物、窒化物、ホウ化物等を挙げることができ、その具体例としては、シリカ、アルミナ、チタニア、ジルコニア、チタン酸バリウム、チタン酸アルミニウム、チタン酸ストロンチウム、チタン酸マグネシウム、酸化亜鉛、酸化クロム、酸化セリウム、酸化アンチモン、酸化タングステン、酸化スズ、酸化テルル、酸化マンガン、酸化ホウ素、炭化ケイ素、炭化ホウ素、炭化チタン、窒化ケイ素、窒化チタン、窒化ホウ素等が挙げられる。これら無機微粒子としては疎水性のものが好ましく、具体的には、シリカ微粒子として、例えば日本アエロジル社製の市販品Ｒ−８０５、Ｒ−９７６、Ｒ−９７４、Ｒ−９７２、Ｒ−８１２、Ｒ−８０９、ヘキスト社製のＨＶＫ−２１５０、Ｈ−２００、キャボット社製の市販品ＴＳ−７２０、ＴＳ−５３０、ＴＳ−６１０、Ｈ−５、ＭＳ−５等が挙げられる。チタン微粒子としては、例えば、日本アエロジル社製の市販品Ｔ−８０５、Ｔ−６０４、テイカ社製の市販品ＭＴ−１００Ｓ、ＭＴ−１００Ｂ、ＭＴ−５００ＢＳ、ＭＴ−６００、ＭＴ−６００ＳＳ、ＪＡ−１、富士チタン社製の市販品ＴＡ−３００ＳＩ、ＴＡ−５００、ＴＡＦ−１３０、ＴＡＦ−５１０、ＴＡＦ−５１０Ｔ、出光興産社製の市販品ＩＴ−Ｓ、ＩＴ−ＯＡ、ＩＴ−ＯＢ、ＩＴ−ＯＣ等が挙げられる。アルミナ微粒子としては、例えば、日本アエロジル社製の市販品ＲＦＹ−Ｃ、Ｃ−６０４、石原産業社製の市販品ＴＴＯ−５５等が挙げられる。また、有機微粒子としては数平均一次粒子径が１０〜２０００ｎｍ程度の球形の有機微粒子を使用することができる。このものとしては、スチレンやメチルメタクリレートなどの単独重合体やこれらの共重合体を使用することができる。
【０１４６】
〈外添剤としての滑剤〉
滑剤としては、例えばステアリン酸の亜鉛、アルミニウム、銅、マグネシウム、カルシウム等の塩、オレイン酸の亜鉛、マンガン、鉄、銅、マグネシウム等の塩、パルミチン酸の亜鉛、銅、マグネシウム、カルシウム等の塩、リノール酸の亜鉛、カルシウム等の塩、リシノール酸の亜鉛、カルシウムなどの塩等の高級脂肪酸の金属塩が挙げられる。これらの外添剤の添加量は、トナーに対して０．１〜５質量％程度が好ましい。
【０１４７】
本発明のトナーは、磁性体を含有する磁性トナーとして単独で使用すること、磁性体を含有しない非磁性トナーとして単独で使用すること、キャリアと混合して二成分現像剤として使用することの何れであってもよいが、二成分現像剤としての使用態様が好ましい。
【０１４８】
本発明のトナーに混合されるキャリアとしては、鉄、フェライト等の磁性材料粒子のみで構成されるキャリア、芯材粒子の表面が樹脂により被覆されてなる樹脂被覆キャリアの何れであってもよいが、耐久性等の観点から樹脂被覆キャリアを使用することが好ましい。
【０１４９】
キャリアの粒子径としては、体積平均粒径で１０〜１００μｍ、好ましくは１５〜８０μｍである。
【０１５０】
キャリアが有する磁化特性としては、飽和磁化で１０〜１００ｅｍｕ／ｇであることが好ましい。
【０１５１】
樹脂被覆キャリアを構成する芯材粒子としては、鉄粉、マグネタイト、各種フェライト等を挙げることができ、これらのうち、マグネタイトおよびフェライトが好ましい。
【０１５２】
〈画像形成装置〉
図２は定着器を内蔵した本発明に係わる画像形成装置の概略構成図である。
【０１５３】
１は画像形成装置の側板であり、給紙カセット２内に収納する転写紙（転写材）３を給紙ローラ４及び重送防止手段５により１枚ずつ送り出し、図示しないガイド板に導かれて搬送ローラ６に到達する。搬送ローラ６から送り出された転写紙３は、レジストローラ７に達し、画像形成とタイミングを合わせて転写領域に送り出される。転写紙３には転写器９により感光体ドラム８よりトナー像を転写された後、未定着トナー像を担持した転写紙は分離器１０により感光体ドラム８から引き離され、定着器１３へと送り込まれる。
【０１５４】
未定着トナー像を担持した転写紙は、定着器１３において、加熱ローラ１４と加圧ローラ１５に狭持搬送される間にトナー像は定着され、排紙ローラを経て画像形成装置外へ排紙される。
【０１５５】
一方、トナー像を転写した後の感光体ドラムは、ドラム表面の残留トナーをクリーニングした後、再び、画像形成に供される。
【０１５６】
図３は、本発明に係わる定着器１３の内部を示した一例の断面図である。
熱源１６を有する加熱ローラ１４と、加圧ローラ１５の間にトナー像を担持した転写紙３が狭持搬送され、２つの排紙ローラ１７と１８の間を通って排紙される。
【０１５７】
実際の定着器では、定着器の樹脂ハウジング２０とその一部を成す天板２１がある。また、加熱ローラ１４と加圧ローラ１５の周囲には、必要に応じて分離爪め２２、２３やクリーニングローラ２４、温度検知センサー２５等が配置されているのが普通である。
【０１５８】
【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るものではない。
【０１５９】
調製例１
（１）核粒子の調製（第１段重合）
撹拌装置、温度センサー、冷却管、窒素導入装置を取り付けた５０００ｍｌのセパラブルフラスコに、アニオン系界面活性剤（ドデシルスルフォン酸ナトリウム：ＳＤＳ）７．０８ｇをイオン交換水３０１０ｇに溶解させた界面活性剤溶液（水系媒体）を仕込み、窒素気流下２３０ｒｐｍの撹拌速度で撹拌しながら、内温を８０℃に昇温させた。
【０１６０】
この界面活性剤溶液に、重合開始剤（過硫酸カリウム：ＫＰＳ）９．２ｇをイオン交換水２００ｇに溶解させた開始剤溶液を添加し、温度を７５℃とした後、スチレン７０．１ｇ、ｎ−ブチルアクリレート１９．９ｇ、メタクリル酸１０．９ｇからなる単量体混合液を１時間かけて滴下し、この系を７５℃にて２時間にわたり加熱、撹拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（１Ｈ）」とする。
【０１６１】
（２）中間層の形成（第２段重合）
撹拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．４ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル５．６ｇからなる単量体混合液に、前記離型剤〔例示化合物１９）〕を７２．０ｇ添加し、８０℃に加温し溶解させて単量体溶液を調製した。
【０１６２】
一方、アニオン系界面活性剤（ＳＤＳ）１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、核粒子の分散液である前記ラテックス（１Ｈ）を固形分換算で２８ｇ添加した後、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム−テクニック社製）により、前記例示化合物１９）の単量体溶液を混合分散させ、均一な分散粒子径（２８４ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０１６３】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を８０℃にて３時間にわたり加熱撹拌することにより重合（第２段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の表面が中間分子量樹脂により被覆された構造の複合樹脂粒子の分散液）を得た。これを「ラテックス（１ＨＭ）」とする。
【０１６４】
（３）外層の形成（第３段重合）
上記のようにして得られたラテックス（１ＨＭ）に、重合開始剤（ＫＰＳ）７．４ｇをイオン交換水２００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン３００ｇ、ｎ−ブチルアクリレート９５ｇ、メタクリル酸１５．３ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル１０．４ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱撹拌することにより重合（第３段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、中間分子量樹脂からなる中間層と、低分子量樹脂からなる外層とを有し、前記中間層に例示化合物１９）が含有されている複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（１ＨＭＬ）」とする。
【０１６５】
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（ゲルパーミエーションクロマトグラフィーにより測定された）、また、この複合樹脂粒子の重量平均粒径は１２２ｎｍであった。
【０１６６】
調製例２
（１）核粒子の調製（第１段重合）
撹拌装置を取り付けたフラスコ内において、スチレン１０５．６ｇ、ｎ−ブチルアクリレート３０．０ｇ、メタクリル酸６．４ｇからなる単量体混合液に、前記例示化合物１６）７２．０ｇを添加し、８０℃に加温し溶解させて単量体溶液を調製した。
【０１６７】
一方、アニオン系界面活性剤（ＳＤＳ）１．６ｇをイオン交換水２７００ｍｌに溶解させた界面活性剤溶液を８０℃に加熱し、この界面活性剤溶液に、循環経路を有する機械式分散機「クレアミックス（ＣＬＥＡＲＭＩＸ）」（エム−テクニック社製）により、前記例示化合物１６）の単量体溶液を混合分散させ、均一な分散粒子径（２６８ｎｍ）を有する乳化粒子（油滴）を含む分散液（乳化液）を調製した。
【０１６８】
次いで、この分散液（乳化液）に、重合開始剤（ＫＰＳ）５．１ｇをイオン交換水２４０ｍｌに溶解させた開始剤溶液と、イオン交換水７５０ｍｌとを添加し、この系を８０℃にて３時間にわたり加熱撹拌することにより重合（第１段重合）を行い、ラテックス（高分子量樹脂からなる樹脂粒子の分散液）を調製した。これを「ラテックス（２Ｈ）」とする。
【０１６９】
（２）外層の形成（第２段重合）
上記のようにして得られたラテックス（２Ｈ）に、重合開始剤（ＫＰＳ）１４．８ｇをイオン交換水４００ｍｌに溶解させた開始剤溶液を添加し、８０℃の温度条件下に、スチレン６００ｇ、ｎ−ブチルアクリレート１９０ｇ、メタクリル酸３０．０ｇ、ｎ−オクチル−３−メルカプトプロピオン酸エステル２０．８ｇからなる単量体混合液を１時間かけて滴下した。滴下終了後、２時間にわたり加熱撹拌することにより重合（第２段重合）を行った後、２８℃まで冷却しラテックス（高分子量樹脂からなる中心部と、低分子量樹脂からなる外層とを有し、前記中心部に例示化合物１６）が含有されている複合樹脂粒子の分散液）を得た。このラテックスを「ラテックス（２ＨＬ）」とする。
【０１７０】
このラテックス（２ＨＬ）を構成する複合樹脂粒子は、１６８，０００および１１，０００にピーク分子量を有するものであり、また、この複合樹脂粒子の重量平均粒径は１２６ｎｍであった。
【０１７１】
トナー１Ｂｋ
ｎ−ドデシル硫酸ナトリウム５９．０ｇをイオン交換水１６００ｍｌに撹拌溶解した。この溶液を撹拌しながら、カーボンブラック「リーガル３３０」（キャボット社製）４２０．０ｇを徐々に添加し、次いで、「クレアミックス」（エム−テクニック社製）を用いて分散処理することにより、着色剤粒子の分散液（以下、「着色剤分散液（Ｂｋ）」という。）を調製した。この着色剤分散液（Ｂｋ）における着色剤粒子の粒子径を、電気泳動光散乱光度計「ＥＬＳ−８００」（大塚電子社製）を用いて測定したところ、重量平均粒子径で９８ｎｍであった。
【０１７２】
調製例１で得られたラテックス（１ＨＭＬ）４２０．７ｇ（固形分換算）と、イオン交換水９００ｇと、着色剤分散液（Ｂｋ）１６６ｇとを、温度センサー、冷却管、窒素導入装置、撹拌装置を取り付けた反応容器（四つ口フラスコ）に入れ撹拌した。内温を３０℃に調整した後、この溶液に５ｍｏｌ／リットルの水酸化ナトリウム水溶液を加えてｐＨを９．０に調整した。
【０１７３】
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、及びメチルビニルケトン０．７ｍｌを、撹拌下、３０℃にて添加した。
【０１７４】
３分後に昇温を開始し、この系を６分間かけて９０℃まで昇温した（昇温速度＝１０℃／分）。その状態で、「コールターカウンターＴＡ−II」にて会合粒子の粒径を測定し、個数平均粒径が５．５μｍになった時点で、塩化ナトリウム８０．４ｇをイオン交換水１０００ｍｌに溶解した水溶液を添加して粒子成長を停止させ、さらに、熟成処理として液温度８５℃にて２時間にわたり加熱撹拌することにより融着を継続させた。その後、８℃／分の条件で３０℃まで冷却し、塩酸を添加してｐＨを２．０に調整し、撹拌を停止した。生成した会合粒子を濾過し、イオン交換水で繰り返し洗浄し、その後、４０℃の温風で乾燥した後、１０リットルヘンシェルミキサーに移し、疎水性シリカ０．８質量％を添加混合することでトナーを得た。このようにして得られたトナーを「トナー１Ｂｋ」とする。
【０１７５】
トナー２Ｂｋ
トナー１Ｂｋにおいてメチルビニルケトンに代えて、ベンジルメチルケトン２ｍｌを加えた以外は同様にしてトナーを得た。このようにして得られたトナーを「トナー２Ｂｋ」とする。
【０１７６】
トナー３Ｂｋ
トナー１Ｂｋにおいてにメチルビニルケトン代えて、エチルビニルケトンを加えた以外は同様にしてトナーを得た。このようにして得られたトナーを「トナー３Ｂｋ」とする。
【０１７７】
トナー４Ｂｋ
トナー１Ｂｋにおいてラテックス（１ＨＭＬ）に代えて、調製例２で得られたラテックス（２ＨＬ）４２０．７ｇ（固形分換算）を使用し、メチルビニルケトン１ｍｌを使用した以外は同様にしてトナーを得た。このようにして得られたトナーを「トナー４Ｂｋ」とする。
【０１７８】
比較用トナー１Ｂｋ
トナー１Ｂｋにおいてビニルケトンを０．１ｍｌ加えた以外は同様にしてトナーを得た。このようにして得られたトナーを「比較用トナー１Ｂｋ」とする。
【０１７９】
比較用トナー２Ｂｋ
トナー１Ｂｋにおいてビニルケトン２０ｍｌを加えた以外は同様にしてトナーを得た。このようにして得られたトナーを「比較用トナー２Ｂｋ」とする。
【０１８０】
各々のトナーについて、粒度及び形状係数等を測定した結果を表１に示した。又、ヘッドスペース法を用いた各微量成分の含有量と、以下の評価項目について評価した結果を表２に示す。
【０１８１】
【表１】

【０１８２】
【表２】

【０１８３】
評価（接触現像方式）
コニカ製デジタル複写機Ｋｏｎｉｃａ７０５０を改造して５００万枚の実写評価を実施した。感光体としては積層型有機感光体を使用した。
【０１８４】
また、定着方法としては、熱ロール定着を使用し、オイル塗布機構、オフセットトナーの清掃機構は取り外して評価した。定着器ハウジングの天板は、厚さ３ｍｍのＡＢＳ製とした。
【０１８５】
また、画像形成条件としては常温常湿環境（２５℃／５５％ＲＨ）にて実施した。
【０１８６】
〈定着率〉
定着率は、付着量０．６ｍｇ／ｃｍ²の１インチ角ベタ画像を採取し、スコッチメンディングテープ（住友３Ｍ社製）で剥離する前後の画像濃度から求めた。
【０１８７】
８０％以上が合格である。
〈ハウジングの変形〉
目視観察により、複写機の定着器側の側板の反り、割れを観察した。
【０１８８】
〈定着器部品のリサイクル〉
５００万枚時点での定着器ハウジング天板の寸法が、評価開始時に対しプラスマイナス１％以内に収まっていれば、リサイクル「可」、それ以上の変形があったとき「不可」とした。
【０１８９】
【発明の効果】
本発明により、定着性の高いトナーを提供することが出来、トナー中に含有される特定の揮発性の成分による装置部品の劣化防止、特に定着器ハウジングや定着器周辺の樹脂部品の変形や割れ等の樹脂劣化を起こさない熱定着用トナーと、それを用いた画像形成方法を提供することが出来る。
【図面の簡単な説明】
【図１】角のないトナー粒子を説明する概略図。
【図２】本発明に係わる画像形成装置の概略構成図。
【図３】本発明に係わる定着器の内部を示した一例の断面図。
【符号の説明】
１ 画像形成装置の側板
２ 給紙カセット
３ 転写紙（転写材）
４ 給紙ローラ
５ 重送防止手段
６ 搬送ローラ
７ レジストローラ
８ 感光体ドラム
１３ 定着器
１４ 加熱ローラ
１５ 加圧ローラ
２０ 樹脂ハウジング
２１ 天板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat fixing toner used in an electrophotographic method and an electrostatic recording method for developing and fixing an electrostatic latent image, and an image forming method using the toner.
[0002]
[Prior art]
In the developing process, the electrostatic latent image developing toner temporarily adheres to the electrostatic latent image formed on the photosensitive member or the like to form a toner image, and then transferred to the transfer material in the transfer process, and then the fixing process. And fixed on the transfer material.
[0003]
In the fixing process, how to produce a robust fixed image is still a big problem. In the study in this field, in recent years, it has been known that a trace amount component in the toner remaining or added in the process of producing the toner affects the fixing property.
[0004]
For example, Japanese Patent Application Laid-Open No. 11-249334 describes an invention in which the amount of residual monomer in a toner is measured by gas chromatography to make it 500 ppm or less. Japanese Patent Laid-Open Nos. 7-104514 and 7-104515 disclose inventions that specify the amount of volatile components of toner using a styrene resin.
[0005]
The above-mentioned trace amount component functions as a plasticizer in the toner and has a preferable function of contributing to improvement of the fixing rate, but on the other hand, it volatilizes by heating and generates a characteristic odor. And chemical attack on resin parts around the fuser. As a result, there arises a problem of causing deformation and cracking of the members of the apparatus.
[0006]
As a method for fixing toner, a method that does not use heat, such as a pressure fixing method, is currently being tried. However, in order to obtain a sufficient fixing strength, a thermal fixing method in which the binder resin in the toner is melted and fixed by heat, such as a hot roll fixing method or a flash fixing method, is used.
[0007]
However, the fixing temperature is about 160 to 220 ° C. in the case of the heat roll fixing method, and in such a temperature environment, as described above, trace components such as raw material monomers remaining in the toner are vaporized to cause odor. In the long-term use, the device members are deformed and cracked, making it difficult to recycle the parts.
[0008]
Resin parts that make up the housing of copiers and the like use resins having excellent moldability, such as ABS resin and polycarbonate resin, as well as excellent resistance to deterioration and chemicals. In the presence of a characteristic trace component (impurity), the deterioration of the resin is accelerated, and the life of the resin is shortened.
[0009]
[Problems to be solved by the invention]
Until now, the existence of the volatile impurities in the toner has not been studied in terms of what is preferable as a component that contributes to the improvement of the thermal fixing rate. None of them focused on measures against durability deterioration.
[0010]
The present invention has been made to solve the above problems.
That is, a first object of the present invention is to provide a toner having high fixability, and a second object of the present invention is to prevent deterioration of apparatus parts due to a specific volatile component contained in the toner. In particular, it is an object of the present invention to provide a heat fixing toner that does not cause resin deterioration such as deformation and cracking of resin parts around the fixing device housing and the fixing device, and an image forming method using the same.
[0011]
[Means for Solving the Problems]
The above-described object of the present invention is achieved by adopting any one of the following configurations.
[0012]
[1] A heat-fixing toner comprising at least 0.2 to 24 ppm of vinyl ketones in a heat-fixing toner comprising at least a resin and a colorant.
[0013]
[2] The heat fixing toner according to [1], wherein the vinyl ketone component is methyl vinyl ketone.
[0014]
[3] The heat fixing toner according to [1] or [2], wherein the variation coefficient of the shape factor is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less.
[0015]
[4] The heat fixing toner according to any one of [1] to [3], wherein the number of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more. .
[0016]
[5] The heat fixing toner according to any one of [1] to [4], wherein the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more. .
[0017]
[6] The heat fixing toner according to any one of [1] to [5], wherein the toner particles having no corners are 50% by number or more.
[0018]
[7] The heat fixing toner according to any one of [1] to [6], wherein the number average particle diameter is 2 to 8 μm.
[0019]
[8] When the particle diameter of the toner particles is D (μm), a natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is a histogram showing the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of the toner particles 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. The heat fixing toner according to any one of [1] to [7], wherein the toner is for heat fixing.
[0020]
[9] The heat fixing toner according to any one of [1] to [8], which is produced by polymerizing a polymerizable monomer in an aqueous medium.
[0021]
[10] The heat fixing toner according to any one of [1] to [9], wherein the toner particles are obtained by salting out / fusing resin particles in an aqueous medium.
[0022]
[11] A toner obtained by salting out / fusion of composite resin particles obtained by a multistage polymerization method and colorant particles, wherein a release agent is contained in a region other than the outermost layer of the composite resin particles. The toner for heat fixing according to any one of [1] to [10], wherein the toner is for heat fixing.
[0023]
[12] An electrostatic latent image is developed using a toner composed of at least a resin and a colorant and containing a vinyl ketone component having 4 to 24 carbon atoms in an amount of 0.2 to 24 ppm, transferred onto a transfer material, and then thermally fixed. An image forming method.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
[0025]
The present invention pays attention to the volatile component contained in the toner component as described above, and improves the fixing property of the toner and the like, and causes less deterioration of the apparatus due to these components. This is based on the fact that components that do not cause deformation or cracking of the resin parts around the fixing device are identified and an appropriate amount is found.
[0026]
In the present invention, in a toner for heat fixing containing at least a binder resin and a colorant, the toner has a vinyl ketone component, and when the vinyl ketone component is measured by the headspace method defined below, the content thereof Is a total of 0.2 to 24 ppm based on the toner particle mass.
[0027]
Examples of the vinyl ketone include methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, normal butyl ketone, t-butyl vinyl ketone, and benzyl vinyl ketone, and methyl vinyl ketone is particularly preferable.
[0028]
Other components constituting the toner such as a binder resin component and a colorant will be described later. When the vinyl ketone component is contained in the toner within the above range, these components function as preferred plasticizers in the toner. And has a preferable effect of contributing to improvement of the fixing rate. When the amount of volatilization is particularly large due to the volatilization of the plasticizer due to heat, chemical attack may be performed on the fixing device housing and resin parts (made of ABS resin or polycarbonate) around the fixing device. However, the present inventors have found that the above compound does not cause the problem of causing deformation and cracking of the members of the apparatus.
[0029]
The trace components composed of the vinyl ketones of the present invention can be used for chemical attack on resin parts, such as when the raw material monomer, polymerization initiator, synthesis solvent, etc. remain in the resin as an impurity, and deformation or cracks in equipment members. Will not cause.
[0030]
These trace components may be added directly in the toner production process, may be used as a by-product during polymerization, or may be supplied from a constituent material such as a colorant. Among these, it is more preferable to add directly in the toner production process.
[0031]
The headspace method used for the determination of vinyl ketone according to the present invention is to enclose toner in an openable / closable container, heat it at the time of heat fixing in a copying machine, and promptly in a state where the container is filled with volatile components. The gas in the container is injected into a gas chromatograph apparatus and a mass spectrometer connected thereto, and the amount of volatile components is measured.
[0032]
Below, the measurement by the head space method is demonstrated in detail.
<Measuring method>
1. Sample collection
Take 0.8 g of sample in a 20 ml headspace vial. The sample amount is weighed to 0.01 g (necessary for calculating the area per unit mass). The vial is then sealed using a septum.
[0033]
2. Sample heating
Place the sample in a 130 ° C. constant temperature bath and heat for 30 minutes.
[0034]
3. Setting gas chromatography separation conditions
A carrier coated with silicone oil SE-30 so as to have a mass ratio of 15% packed in a column having an inner diameter of 3 mm and a length of 3 m is used as a separation column. The separation column is attached to a gas chromatograph, and He is used as a carrier to flow at a rate of 50 ml / min. The temperature of the separation column is set to 40 ° C., and measurement is performed while the temperature is increased to 260 ° C. at 15 ° C./min. Hold for 5 minutes after reaching 260 ° C.
[0035]
4). Sample introduction
Remove the vial from the thermostat and immediately inject 1 ml into the separation column with a gas tight syringe.
[0036]
5. Calculation
For quantitative determination of vinyl ketone components, a calibration curve is prepared in advance using ethyl vinyl ketone as a reference substance, and the concentration of each component is determined.
[0037]
6). equipment
1) Headspace conditions
Headspace equipment
HP 7694 Head Space Sampler manufactured by HP
Temperature condition
Transfer line: 200 ° C
Loop temperature: 200 ° C
Sample volume: 0.8g / 20ml vial
2) GC / MS conditions
HP 5890 made by GC HP
HP 5971 made by MS HP
Column: HP-624 30m x 0.25mm
Oven temperature: 40 ° C (3min) -15 ° C / min-260 ° C
Measurement mode: SIM
Next, the toner of the present invention will be described.
[0038]
The toner of the present invention is produced by subjecting a monomer to emulsion polymerization in a suspension polymerization method or a liquid obtained by adding an emulsified liquid of necessary additives to produce fine polymer particles. Etc. can be produced by an emulsion associating method in which these are added and associated. A method of preparing by mixing with a dispersion liquid such as a release agent and a colorant necessary for the composition of the toner at the time of association, and a toner component such as a release agent and a colorant dispersed in the monomer And a method of emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.
[0039]
In addition, in order to add the vinyl ketone component according to the present invention to the toner, it may be mixed with a dispersion liquid of a release agent or a colorant necessary for the constitution of the toner at the time of the association, or a single amount A method may be employed in which these vinyl ketone components are added and dispersed together with toner constituents such as a release agent and a colorant in the body, followed by emulsion polymerization.
[0040]
In suspension polymerization and emulsion polymerization, it is preferable to use an aqueous medium, and the aqueous medium indicates that at least 50% by mass of water is contained.
[0041]
That is, for example, in the suspension polymerization method, a colorant in a polymerizable monomer, various constituent materials such as a release agent, a charge control agent, and a polymerization initiator as necessary, and further, if necessary, The vinyl ketone component of the invention is added, and 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 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.
[0042]
Further, as a method for producing the toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can 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.
[0043]
That is, for example, a dispersion particle composed of resin particles emulsion-polymerized with an emulsifier and a constituent material such as a colorant, or a dispersion particle obtained by associating fine particles composed of a resin and a colorant is used. At the same time as adding an agent for salting out, the resin particles are heated to a temperature higher than the glass transition point of the polymer and fused to gradually grow the particle size while forming fused particles. When the target particle size is reached, a large amount of water is added to stop particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated and dried in a fluid state while containing water. There is a method of forming toner by doing so.
[0044]
The alcohol component according to the present invention may be added in this association step. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the flocculant.
[0045]
As the polymerizable monomer constituting the resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decyl Styrene, styrene such as pn-dodecylstyrene or styrene derivatives, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, Methacrylic acid ester derivatives such as lauryl tacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylates such as isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, Halogenated vinyls such as vinyl bromide, vinyl fluoride, vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate, vinyl benzoate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as Tell, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. There are acrylic acid or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, acrylamide and the like. These vinyl monomers can be used alone or in combination.
[0046]
Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.
[0047]
Furthermore, polyfunctionality such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.
[0048]
These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris The (t-butylperoxy) triazine peroxide polymerization initiator or a peroxide, such as and the like polymeric initiator having a side chain.
[0049]
Moreover, when using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.
[0050]
Dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate , Bentonite, silica, alumina and the like. Furthermore, those generally used as surfactants such as polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as the dispersion stabilizer.
[0051]
As the resin excellent in the present invention, those having a glass transition point of 20 to 90 ° C. are preferred, and those having a softening point of 80 to 220 ° C. are preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Further, these resins preferably have a molecular weight measured by gel permeation chromatography of 1,000 to 100,000 in terms of number average molecular weight (Mn) and 2000 to 1,000,000 in terms of weight average molecular weight (Mw). Further, the molecular weight distribution is preferably such that Mw / Mn is 1.5 to 100, particularly 1.8 to 70.
[0052]
However, in the present invention, it is preferable to use composite resin particles obtained by a multistage polymerization method as the resin particles prepared by the emulsion polymerization. In the present invention, the composite resin particles and the colorant particles are preferably salted out / fused with an aggregating agent to obtain a toner, and a release agent is contained in a region other than the outermost layer of the composite resin particles. It is preferable to obtain a heat fixing toner using the composite resin particles.
[0053]
In particular, a toner obtained by salting out / fusion-bonding composite resin particles obtained by a two-stage polymerization method and colorant particles, wherein the composite resin particles have a peak or shoulder molecular weight of 100,000 to 1, A center part (core) formed from a high molecular weight resin having a molecular weight of 1,000,000 and an outer layer (shell) formed from a low molecular weight resin having a peak or shoulder molecular weight of 1,000 to 50,000, It is preferable that a release agent is contained in the center (core).
[0054]
Also, a toner obtained by salting out / fusion-bonding composite resin particles obtained by a three-stage polymerization method and colorant particles, wherein the composite resin particles have a peak or shoulder molecular weight of 100,000 to 1, A central portion (core) formed from a high molecular weight resin having a molecular weight of 1,000,000, an intermediate layer formed from a resin having a peak or shoulder molecular weight of 25,000 to 150,000, and a peak or shoulder molecular weight of 1,000 to 50 And an outer layer (shell) formed from a low molecular weight resin having a molecular weight of 1,000, and a release agent is preferably contained in the intermediate layer.
[0055]
The “composite resin particles” constituting the toner preferably used in the present invention are made of a resin having a different molecular weight and / or composition from the resin forming the core particles so as to cover the surface of the core particles made of resin. It shall mean the resin particle of the multilayer structure in which the 1 or 2 or more coating layer is formed.
[0056]
Further, the “central part (core)” of the composite resin particle refers to “core particle” constituting the composite resin particle.
[0057]
The “outer layer (shell)” of the composite resin particle refers to the outermost layer among “one or more coating layers” constituting the composite resin particle.
[0058]
The “intermediate layer” of the composite resin particles refers to a coating layer formed between the central portion (core) and the outer layer (shell).
[0059]
The molecular weight distribution of the composite resin particles is not monodisperse, and the composite resin particles usually have a molecular weight gradient from the center (core) to the outer layer (shell).
[0060]
In the present invention, the “multi-stage polymerization method” for obtaining composite resin particles means that in the presence of resin particles (n) obtained by polymerizing monomer (n) (n-th stage), The monomer (n + 1) is polymerized (step n + 1), and the polymer of the monomer (n + 1) is dispersed on the surface of the resin particle (n) (the constituent resin of the resin particle (n) is dispersed and / or Or a method of forming a coating layer (n + 1) made of resins having different compositions.
[0061]
Here, when the resin particle (n) is a core particle (n = 1), it becomes “two-stage polymerization method”, and when the resin particle (n) is a composite resin particle (n ≧ 2), It becomes a multistage polymerization method of three or more stages.
[0062]
In the present invention, “salting out / fusing” means that salting out (aggregation of particles) and fusing (disappearance of the interface between particles) occur simultaneously or salting out and fusing occur simultaneously. Say.
[0063]
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. .
[0064]
A plurality of resins having different compositions and / or molecular weights are present in the composite resin particles obtained by the multistage polymerization method. Accordingly, the toner obtained by salting out / fusion-bonding the composite resin particles and the colorant particles has extremely small variations in composition, molecular weight, and surface characteristics among the toner particles.
[0065]
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.
[0066]
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.
[0067]
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.
[0068]
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.
[0069]
<Chain transfer agent>
Generally used chain transfer agents can be used for the purpose of adjusting the molecular weight of the resin constituting the composite resin particles.
[0070]
The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, n-octyl-3-mercaptopropionate, terpinolene, carbon tetrabromide and α-methyl. Styrene dimer or the like is preferably used.
[0071]
<Polymerization initiator>
The radical polymerization initiator for obtaining the composite resin particles can be appropriately used as long as it is a water-soluble radical polymerization initiator.
[0072]
Specific examples of the radical polymerization initiator include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis ( 2-amidinopropane) salts, etc.), peroxide compounds and the like.
[0073]
Furthermore, the above 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 is increased, the polymerization temperature can be lowered, and the polymerization time can be further shortened.
[0074]
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, and is, for example, in the range of 50 to 90 ° C. However, it is possible to polymerize at room temperature or a temperature slightly higher by using a polymerization initiator that starts at room temperature such as a combination of hydrogen peroxide and a reducing agent (such as ascorbic acid).
[0075]
<Surfactant>
In order to perform polymerization using the above-mentioned radical polymerizable monomer, it is necessary to perform oil droplet dispersion in an aqueous medium using a surfactant. Although it does not specifically limit as surfactant which can be used in this case, The following ionic surfactant can be mentioned as an example of a suitable thing.
[0076]
Examples of the ionic surfactant include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6 Sodium sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate, etc.), sulfuric acid Ester 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, potassium stearate) Beam, calcium oleate and the like).
[0077]
Nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester Etc.
[0078]
The weight average particle diameter (dispersed particle diameter) of the composite resin particles is preferably in the range of 10 to 1000 nm, more preferably in the range of 30 to 300 nm.
[0079]
This weight average particle diameter is a value measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).
[0080]
The glass transition temperature (Tg) of the resin component (resin introduced by the composite resin particles) constituting the toner of the present invention is preferably in the range of 48 to 74 ° C, more preferably 52 to 65 ° C.
[0081]
Moreover, it is preferable that the softening point of the said resin component exists in the range of 95-140 degreeC. Here, the glass transition point (Tg) of the resin component refers to a value measured by DSC, and the intersection of the base line and the endothermic peak slope is defined as the glass transition point. Specifically, using a differential scanning calorimeter, the temperature is raised to 100 ° C., left at that temperature for 3 minutes, and then cooled to room temperature at a temperature drop of 10 ° C./min. Next, when this sample was measured at a heating rate of 10 ° C./min, an extension of the baseline below the glass transition point and a tangent line indicating the maximum slope from the peak rising portion to the peak apex. The intersection point is shown as the glass transition point.
[0082]
Here, as a measuring device, DSC-7 manufactured by PerkinElmer, Inc. can be used.
[0083]
Moreover, the softening point of a resin component means the value measured using the flow tester. Specifically, using a flow tester “CFT-500” (manufactured by Shimadzu Corporation), the diameter of the pore of the die is 1 mm, the length is 1 mm, and the load is 20 kg / cm.²1 cm under the condition of a heating rate of 6 ° C./min^ThreeThe temperature corresponding to 1/2 of the height from the outflow start point to the outflow end point when the sample is melted out is shown as the softening point.
[0084]
<Release agent>
The toner according to the present invention is an association-type toner particle obtained by salting out / fusion-bonding composite resin particles containing a release agent in a region other than the outermost layer (center portion or intermediate layer) and colorant particles. Is preferred.
[0085]
Examples of the release agent constituting the toner of the present invention include various known ones that can be dispersed in water. Specific examples include olefin waxes such as polypropylene and polyethylene, modified products of these olefin waxes, natural waxes such as carnauba wax and rice wax, and amide waxes such as fatty acid bisamides.
[0086]
As a suitable release agent constituting the toner of the present invention, there may be mentioned those composed of a crystalline ester compound (hereinafter referred to as “specific ester compound”) represented by the following general formula (1).
[0087]
General formula (1)
R¹-(OCOR²)_n
Where R¹And R²Each represents a hydrocarbon group having 1 to 40 carbon atoms which may have a substituent, and n is an integer of 1 to 4.
[0088]
In general formula (1) showing a specific ester compound, R¹And R²Each represents a hydrocarbon group which may have a substituent.
[0089]
Hydrocarbon group R¹The number of carbon atoms is 1 to 40, preferably 1 to 20, and more preferably 2 to 5.
[0090]
Hydrocarbon group R²The number of carbon atoms is from 1 to 40, preferably from 16 to 30, and more preferably from 18 to 26.
[0091]
In the general formula (1), n is an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4.
[0092]
The specific ester compound can be suitably synthesized by a dehydration condensation reaction between an alcohol and a carboxylic acid.
[0093]
Specific examples of the specific ester compound include compounds represented by the following formulas 1) to 22).
[0094]
(Specific exemplified compounds)
[0095]
[Chemical 1]

[0096]
[Chemical formula 2]

[0097]
<Ratio of release agent>
The content of the release agent constituting the toner according to the present invention is usually 1 to 30% by mass, preferably 2 to 20% by mass, and more preferably 3 to 15% by mass.
[0098]
<Contained area of release agent in composite resin particles>
In the toner using the composite resin particle according to the present invention, the release agent in the composite resin particle constituting the toner may be contained in a region (central portion or intermediate layer) other than the outermost layer of the composite resin particle. .
[0099]
As a result, since the outermost layer of the composite resin particles does not contain a release agent that lowers the adhesion between particles, the composite resin particles adhere firmly in the salting-out / fusion process, and the crushing strength of the composite resin particles is reduced. High fusing particles (toner particles constituting the toner of the present invention according to claim 4) are formed.
[0100]
The flocculant used for fusing by salting out is not particularly limited, but a material selected from metal salts is preferably used. Specifically, as a monovalent metal, for example, an alkali metal salt such as sodium, potassium or lithium, as a divalent metal, for example, an alkaline earth metal salt such as calcium or magnesium, or a divalent metal such as manganese or copper. And salts of trivalent metals such as iron and aluminum, and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc. Can be mentioned. These may be used in combination.
[0101]
These flocculants are preferably added in an amount equal to or higher than the critical aggregation concentration. The critical flocculation concentration is an index relating to the stability of the aqueous dispersion, and indicates a concentration at which flocculation occurs when a flocculant is added. This critical aggregation concentration varies greatly depending on the emulsified components and the dispersant itself. For example, it is described in Seizo Okamura et al., “Polymer Chemistry 17, 601 (1960) edited by Polymer Society” and the like, and a detailed critical aggregation concentration can be obtained. As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is defined as the critical aggregation concentration. You can ask for it.
[0102]
The addition amount of the flocculant of the present invention may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.
[0103]
The solvent that dissolves infinitely means a solvent that dissolves infinitely in water, and in the present invention, a solvent that does not dissolve the formed resin is selected. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, methoxyethanol, and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. In particular, ethanol, propanol, and isopropanol are preferable.
[0104]
The addition amount of the infinitely soluble solvent is preferably 1 to 100% by volume with respect to the polymer-containing dispersion to which the flocculant is added.
[0105]
In order to make the shape uniform, it is preferable to fluidly dry a slurry in which 10% by mass or more of water is present after preparing and filtering colored particles. Those having a polar group are preferred. The reason for this is considered to be that it is particularly easy to make the shape uniform, in order to exhibit the effect that the water present is somewhat swollen with respect to the polymer in which the polar group is present.
[0106]
The toner of the present invention contains at least a resin and a colorant, but may contain a release agent, a charge control agent, or the like, which is a fixability improving agent, if necessary. Further, an external additive composed of inorganic fine particles or organic fine particles may be added to the toner particles containing the resin and the colorant as main components.
[0107]
<Colorant>
As the colorant used in the toner of the present invention, carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used. Examples of the carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black. used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.
[0108]
As the dye, 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 a mixture thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 93, 94, 138, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.
[0109]
As a method for adding the colorant, the polymer particles prepared by the emulsion polymerization method are added at the stage of agglomerating by adding an aggregating agent, and the polymer is colored, or at the stage of polymerizing the monomer. The method of adding, polymerizing, and making it a colored particle etc. can be used. In addition, when adding a coloring agent in the step which prepares a polymer, it is preferable to use it, treating the surface with a coupling agent etc. so that radical polymerization property may not be inhibited.
[0110]
Further, a low molecular weight polypropylene (number average molecular weight = 1500 to 9000), a low molecular weight polyethylene, or the like as a fixing property improving agent may be added.
[0111]
Similarly, various known charge control agents and those that can be dispersed in water can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof. In addition, it is preferable that the number average primary particle diameter of these charge control agent and fixability improving agent particles is about 10 to 500 nm in a dispersed state. In the above-described suspension polymerization method toner in which a toner component obtained by dispersing or dissolving a toner component such as a colorant in the polymerizable monomer is suspended in an aqueous medium and then polymerized. The shape of the toner particles can be controlled by controlling the flow of the medium therein. The present invention is also useful in so-called suspension polymerization toners by such a method.
[0112]
Further, in a so-called pulverized toner obtained by a method in which a binder resin is separately prepared, kneaded with a toner constituent such as a colorant, pulverized, mixed and dispersed with an external additive such as silica, and the like to obtain a pulverized toner. It is useful as well. Various conventional toner production methods can be applied as the method for producing the pulverized toner particles. For example, as a general example, first, a resin, a colorant, a wax, a charge control agent and the like are uniformly dispersed and mixed in a mixer, Next, the mixture is melt kneaded with a closed kneader or a single or twin screw extruder, cooled, coarsely pulverized with a crusher, hammer mill, etc., finely pulverized with a jet mill, high-speed rotor rotary mill, etc. You may manufacture by classifying with a classifier (For example, an inertia class elbow jet, a centrifugal classification microplex, DS separator etc.). The average particle diameter of the toner is preferably 3 to 20 μm. In the melt kneading step, it is also preferable to adjust the trace component of the present invention within a range that does not impair the charging performance and fixing performance as the final toner. In the study by the present inventors, although there is fluctuation, the trace component of the present invention is reduced by about 20 to 40% by the melt-kneading process.
[0113]
In the heat fixing toner of the present invention, in order to obtain high fixability, the variation coefficient of the shape factor is preferably 16% or less, and the number variation coefficient in the number particle size distribution is preferably 27% or less. That is, by making the shape distribution of the toner itself uniform, it is possible to make the heat conduction and heat deformation during fixing uniform and prevent the occurrence of fixing failure.
[0114]
Further, as a result of further investigation by the present inventors, toner particles having no corners exhibit the same effect even if the variation in shape is somewhat large due to the smoothness of the surface. That is, it is preferable to use a toner having 50% by number or more of toner particles having no corners.
[0115]
Further, as a result of the study by the present inventors, it has been found that even when the specific shape is made uniform, the thermal deformation of the toner can be made uniform and the same effect can be exhibited. That is, it is preferable to use a toner having 65% by number or more of toner particles having a shape factor in the range of 1.0 to 1.6, preferably 1.2 to 1.6.
[0116]
In the present invention, the shape factor of the toner is expressed by the following formula, and indicates the degree of roundness of the toner particles.
[0117]
Shape factor = ((maximum diameter / 2)²× π) / projection area
Here, the maximum diameter refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines. The projected area refers to the area of the projected image of the toner particles on the plane.
[0118]
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.
[0119]
The method for controlling the shape factor is not particularly limited. For example, 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 due to impact force in a gas phase, or a method in which a toner is not dissolved in a solvent and a swirl flow is applied. To prepare a toner having a shape factor of 1.0 to 1.6, or 1.2 to 1.6, and adding the toner into a normal toner so as to be within the range of the present invention. There is. Further, there is a method of preparing a toner having a shape factor adjusted to 1.0 to 1.6 or 1.2 to 1.6 by controlling the entire shape at the stage of preparing a so-called polymerization toner.
[0120]
Among the above methods, the polymerization toner is preferable because it is simple as a production method and has excellent surface uniformity as compared with the pulverized toner.
[0121]
In the present invention, the variation coefficient of the shape factor of the toner is calculated from the following equation.
Coefficient of variation = (S / K) x 100 (%)
In the formula, S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.
[0122]
The variation coefficient of the shape factor is 16% or less, preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, voids in the transferred toner layer are reduced, fixing property is improved, and offset is less likely to occur. In addition, the charge amount distribution becomes sharp and the image quality is improved.
[0123]
Toner particles that are being formed in the process of polymerizing, fusing, and controlling the shape of resin particles (polymer particles) in order to uniformly control the shape factor of the toner and the coefficient of variation of the shape factor without variation in lots. An appropriate process end time may be determined while monitoring the characteristics of the (colored particles).
[0124]
Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. In other words, in the case of a polymerization method toner that is formed by incorporating measurement such as shape in-line, for example, by associating or fusing resin particles in an aqueous medium, the shape and particle size are measured while performing sequential sampling in the fusing step. The reaction is stopped when the desired shape is obtained.
[0125]
The monitoring method is not particularly limited, but a flow type particle image analyzer FPIA-2000 (manufactured by Sysmec) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field and is constantly monitored to measure the shape and the like, and the reaction is stopped when the desired shape is obtained.
[0126]
In the present invention, the number particle size distribution and the number variation coefficient of the toner are measured by a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikka Kisha Co., Ltd.) for outputting the particle size distribution and a personal computer are connected. The aperture used in the Coulter Multisizer was 100 μm, and the volume and number of toners 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 the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution.
[0127]
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).
[0128]
In the present invention, the toner number variation coefficient is preferably 27% or less, more 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.
[0129]
In the present invention, the method for controlling the number variation coefficient 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 separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by using a centrifuge and controlling the rotation speed.
[0130]
In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to make the number variation coefficient in the number particle size distribution 27% or less. In the suspension polymerization method, it is necessary to disperse a polymerizable monomer in an oil droplet having a desired size as a toner in a system medium before polymerization. That is, mechanical shearing with a homomixer or homogenizer is repeated for large oil droplets of a polymerizable monomer to reduce the oil droplets to the size of toner particles. In the method using shearing, the number particle size distribution of the obtained oil droplets is wide, and therefore the particle size distribution of the toner obtained by polymerizing the oil droplets is also wide. For this reason, classification operation is essential.
[0131]
In the present invention, the toner particles having no corners refer to toner particles that do not substantially have protrusions that concentrate electric charges or that easily wear due to stress. Specifically, the following toner particles are used. Toner particles without corners. That is, as shown in FIGS. 1A, 1B, and 1C, a circle having a major axis of the toner particle L and a radius R of L / 10 is in contact with the toner particle peripheral line at one point. On the other hand, when the inside is rolled, the case where the circle does not substantially protrude outside the toner is referred to as toner particles having no corners. The case where it does not protrude substantially refers to one or less protrusions where the protruding circle exists. The major axis of the toner particles refers to the width of the particle that maximizes the interval between the parallel lines when the projected image of the toner particles on the plane is sandwiched between two parallel lines.
[0132]
The measurement of toner without corners was performed as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.
[0133]
In the toner of the present invention, the proportion of toner particles having no corners is preferably 50% by number or more, and 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 toner having excessive adhesion to the surface of the developer conveying member. In addition, the contamination of the developer conveying member can be suppressed, and the charge amount can be sharpened. In addition, toner particles that easily wear and break and toner particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.
[0134]
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.
[0135]
Further, in the polymerization toner formed by associating or fusing the resin particles, the fusing particle surface has many irregularities at the fusing stop stage, and the surface is not smooth, but the temperature in the shape control step, By making appropriate conditions such as the number of revolutions of the stirring blade and the stirring time, a toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles. For example, by setting the rotational speed to be higher than the glass transition temperature of the resin particles, the toner can be formed with a smooth surface and no corners.
[0136]
The toner of the present invention preferably has a number average particle diameter of 2 to 8 μm. When the toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and further the composition of the polymer itself.
[0137]
When the number average particle diameter is 2 to 8 μm, it is possible to reduce the presence of excessively adhering toner or low adhering toner on the developer conveying member in the fixing step, and developability can be maintained over a long period of time. And the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.
[0138]
As the toner of the present invention, when the particle size of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the number-based particle size distribution is divided into a plurality of classes at intervals of 0.23. In the histogram shown, the sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class and the relative frequency (m2) of the toner particles included in the next most frequent class after the most frequent class is 70. % Of the toner is preferable. 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.
[0139]
In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram was created by transferring the particle size data of the sample measured by the Coulter Multisizer to the computer via the I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.
[0140]
Measurement condition
(1) Aperture: 100 μm
(2) Sample preparation method: An appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml of an electrolytic solution (ISOTON R-11 (manufactured by Coulter Scientific Japan)) and stirred, and a measurement sample of 10 to 20 mg is added thereto. Add This system is prepared by dispersing for 1 minute with an ultrasonic disperser.
[0141]
Next, as for numerical values according to the present invention, conventionally known numerical values of toner will be described. This value varies depending on the manufacturing method.
[0142]
In the case of pulverized toner, the proportion of toner particles having a shape factor of 1.2 to 1.6 is about 60% by number. The variation coefficient of the shape factor of this is about 20%. Further, in the pulverization method, in order to reduce the particle size while repeating the crushing, the toner particles have more corners, and the proportion of toner particles without corners is 30% by number or less. Therefore, in order to obtain a rounded toner with uniform shapes and no corners, a process for spheroidizing with heat or the like as described above is required as a method for controlling the shape factor. In addition, the number variation coefficient in the number particle size distribution is about 30% when the classification operation after pulverization is one time, and in order to make the number variation coefficient 27% or less, it is necessary to repeat the classification operation. There is.
[0143]
In the case of a toner by suspension polymerization, since it is conventionally polymerized in a laminar flow, substantially spherical toner particles are obtained. For example, in the toner described in JP-A-56-130762, the shape factor is 1 The ratio of toner particles having a diameter of 2 to 1.6 is about 20% by number, the coefficient of variation of the shape factor is about 18%, and the ratio of toner particles without corners is about 85% by number. In addition, as described above in the method for controlling the number variation coefficient in the number particle size distribution, mechanical shearing is repeatedly performed on large oil droplets of the polymerizable monomer to reduce the oil droplets to the size of toner particles. Therefore, the distribution of the oil droplet diameter is widened, and therefore, the particle size distribution of the obtained toner is wide and the number variation coefficient is as large as about 32%. To reduce the number variation coefficient, the technique described in the above publication is used. If the toner is produced based on the classification, a classification operation is required.
[0144]
In the polymerization method toner formed by associating or fusing resin particles, for example, in the toner described in JP-A-63-186253, the ratio of toner particles having a shape factor of 1.2 to 1.6 Is about 60% by number, the coefficient of variation of the shape factor is about 18%, and the proportion of toner particles without corners is about 44% by number. Further, the particle size distribution of the toner is wide, the number variation coefficient is 30%, and classification operation is necessary to reduce the number variation coefficient.
[0145]
<External additive>
In the present invention, conventionally known inorganic fine particles and organic fine particles can be used from the viewpoint of imparting fluidity to the colored particles. Examples of the compound constituting the inorganic fine particles include various inorganic oxides, nitrides, borides and the like. Specific examples thereof include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, Strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, Examples thereof include boron nitride. These inorganic fine particles are preferably hydrophobic. Specifically, as silica fine particles, for example, commercially available products R-805, R-976, R-974, R-972, R-812, R manufactured by Nippon Aerosil Co., Ltd. -809, HVK-2150 and H-200 manufactured by Hoechst, and commercially available products TS-720, TS-530, TS-610, H-5, and MS-5 manufactured by Cabot. Examples of the titanium fine particles include commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, and JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc. are mentioned. Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd. As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. As this, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.
[0146]
<Lubricant as an external additive>
Examples of lubricants include, for example, zinc stearate, aluminum, copper, magnesium, calcium, etc., zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. And salts of higher fatty acids such as zinc of linoleic acid, salts of calcium, etc., zinc of ricinoleic acid, salts of calcium, etc. The amount of these external additives added is preferably about 0.1 to 5% by mass relative to the toner.
[0147]
The toner of the present invention can be used alone as a magnetic toner containing a magnetic substance, used alone as a non-magnetic toner containing no magnetic substance, or mixed with a carrier and used as a two-component developer. However, the use mode as a two-component developer is preferable.
[0148]
The carrier mixed with the toner of the present invention may be either a carrier composed only of magnetic material particles such as iron or ferrite, or a resin-coated carrier in which the surface of the core material particles is coated with a resin. From the viewpoint of durability and the like, it is preferable to use a resin-coated carrier.
[0149]
The particle diameter of the carrier is 10 to 100 μm, preferably 15 to 80 μm in volume average particle diameter.
[0150]
The magnetization characteristic of the carrier is preferably 10 to 100 emu / g in saturation magnetization.
[0151]
Examples of the core particles constituting the resin-coated carrier include iron powder, magnetite, and various ferrites. Among these, magnetite and ferrite are preferable.
[0152]
<Image forming device>
FIG. 2 is a schematic configuration diagram of an image forming apparatus according to the present invention having a built-in fixing device.
[0153]
Reference numeral 1 denotes a side plate of the image forming apparatus. The transfer paper (transfer material) 3 accommodated in the paper feed cassette 2 is fed one by one by the paper feed roller 4 and the double feed prevention means 5 and guided to a guide plate (not shown). It reaches the conveying roller 6. The transfer paper 3 sent out from the conveying roller 6 reaches the registration roller 7 and is sent out to the transfer area in synchronism with image formation. After the toner image is transferred from the photosensitive drum 8 to the transfer paper 3 by the transfer device 9, the transfer paper carrying the unfixed toner image is pulled away from the photosensitive drum 8 by the separator 10 and sent to the fixing device 13. It is.
[0154]
The transfer paper carrying the unfixed toner image is fixed by the fixing device 13 while being nipped and conveyed between the heating roller 14 and the pressure roller 15, and is discharged to the outside of the image forming apparatus via the discharge roller. Is done.
[0155]
On the other hand, the photosensitive drum after the toner image is transferred is subjected to image formation again after cleaning the residual toner on the drum surface.
[0156]
FIG. 3 is a sectional view showing an example of the inside of the fixing device 13 according to the present invention.
The transfer paper 3 carrying a toner image is sandwiched and conveyed between a heating roller 14 having a heat source 16 and a pressure roller 15, and discharged between two discharge rollers 17 and 18.
[0157]
In an actual fixing device, there are a resin housing 20 of the fixing device and a top plate 21 forming a part thereof. In addition, separation pawls 22 and 23, a cleaning roller 24, a temperature detection sensor 25, and the like are generally disposed around the heating roller 14 and the pressure roller 15 as necessary.
[0158]
【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.
[0159]
Preparation Example 1
(1) Preparation of core particles (first stage polymerization)
Surfactant prepared by dissolving 7.08 g of an anionic surfactant (sodium dodecyl sulfonate: SDS) in 3010 g of ion-exchanged water in a 5000 ml separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen introducing device The solution (aqueous medium) was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.
[0160]
To this surfactant solution, an initiator solution prepared by dissolving 9.2 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water was added, the temperature was adjusted to 75 ° C., and then 70.1 g of styrene, n -A monomer mixture composed of 19.9 g of butyl acrylate and 10.9 g of methacrylic acid was added dropwise over 1 hour, and this system was polymerized by heating and stirring at 75 ° C for 2 hours (first stage polymerization). And a latex (a dispersion of resin particles made of a high molecular weight resin) was prepared. This is referred to as “latex (1H)”.
[0161]
(2) Formation of intermediate layer (second stage polymerization)
In a flask equipped with a stirrer, 105.6 g of styrene, 30.0 g of n-butyl acrylate, 6.4 g of methacrylic acid, 5.6 g of n-octyl-3-mercaptopropionic acid ester, 72.0 g of the release agent [Exemplary Compound 19)] was added, and the mixture was heated to 80 ° C. and dissolved to prepare a monomer solution.
[0162]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (SDS) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and the latex (dispersed core particle) was added to the surfactant solution. 1H) was added in an amount of 28 g in terms of solid content, and then the monomer solution of Exemplified Compound 19) was mixed and dispersed with a mechanical disperser “CLEARMIX” (manufactured by M-Technique) having a circulation path. A dispersion (emulsion) containing emulsion particles (oil droplets) having a uniform dispersed particle diameter (284 nm) was prepared.
[0163]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to this dispersion (emulsion), and the system was heated at 80 ° C. Polymerization (second stage polymerization) was carried out by heating and stirring for 3 hours to obtain latex (a dispersion of composite resin particles having a structure in which the surface of resin particles made of a high molecular weight resin was coated with an intermediate molecular weight resin). This is referred to as “latex (1HM)”.
[0164]
(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 under a temperature condition of 80 ° C., 300 g of styrene, 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 portion made of a high molecular weight resin, an intermediate layer made of an intermediate molecular weight resin, A dispersion of composite resin particles) having an outer layer made of a molecular weight resin and containing the exemplary compound 19) in the intermediate layer was obtained. This latex is referred to as “latex (1HML)”.
[0165]
The composite resin particles constituting the latex (1HML) have peak molecular weights of 138,000, 80,000 and 13,000 (measured by gel permeation chromatography), and the composite resin particles The weight average particle size of was 122 nm.
[0166]
Preparation Example 2
(1) Preparation of core particles (first stage polymerization)
In a flask equipped with a stirrer, 72.0 g of the exemplified compound 16) was added to a monomer mixture composed of 105.6 g of styrene, 30.0 g of n-butyl acrylate, and 6.4 g of methacrylic acid, and 80 ° C. The monomer solution was prepared by heating and dissolving.
[0167]
On the other hand, a surfactant solution in which 1.6 g of an anionic surfactant (SDS) was dissolved in 2700 ml of ion-exchanged water was heated to 80 ° C., and a mechanical disperser “Claire having a circulation path was added to the surfactant solution. Mix (CLEARMIX) (manufactured by M-Technique) mixed and dispersed the monomer solution of Exemplified Compound 16), and a dispersion containing emulsified particles (oil droplets) having a uniform dispersed particle size (268 nm) ( Emulsified liquid) was prepared.
[0168]
Next, an initiator solution prepared by dissolving 5.1 g of a polymerization initiator (KPS) in 240 ml of ion-exchanged water and 750 ml of ion-exchanged water were added to this dispersion (emulsion), and the system was heated at 80 ° C. Polymerization (first stage polymerization) was carried out by heating and stirring for 3 hours to prepare latex (a dispersion of resin particles made of a high molecular weight resin). This is referred to as “latex (2H)”.
[0169]
(2) Formation of outer layer (second stage polymerization)
An initiator solution obtained by dissolving 14.8 g of a polymerization initiator (KPS) in 400 ml of ion-exchanged water is added to the latex (2H) obtained as described above, and 600 g of styrene under a temperature condition of 80 ° C. A monomer mixed solution consisting of 190 g of n-butyl acrylate, 30.0 g of methacrylic acid, and 20.8 g of n-octyl-3-mercaptopropionic acid ester was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (second-stage polymerization) is performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and having a latex (a central portion made of a high molecular weight resin and an outer layer made of a low molecular weight resin). A dispersion of composite resin particles) containing the exemplified compound 16) in the center was obtained. This latex is referred to as “latex (2HL)”.
[0170]
The composite resin particles constituting the latex (2HL) had peak molecular weights of 168,000 and 11,000, and the weight average particle size of the composite resin particles was 126 nm.
[0171]
Toner 1Bk
59.0 g of sodium n-dodecyl sulfate was dissolved in 1600 ml of ion-exchanged water with stirring. While stirring this solution, 420.0 g of carbon black “Regal 330” (Cabot Corporation) was gradually added, and then dispersed by using “Cleamix” (M-Technics Corporation) to give a coloring. A dispersion of agent particles (hereinafter referred to as “colorant dispersion (Bk)”) was prepared. When the particle diameter of the colorant particles in this colorant dispersion (Bk) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the weight average particle diameter was 98 nm. .
[0172]
420.7 g (in terms of solid content) of latex (1HML) obtained in Preparation Example 1, 900 g of ion-exchanged water, and 166 g of a colorant dispersion (Bk), a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device Was stirred in a reaction vessel (four-necked flask). After adjusting the internal temperature to 30 ° C., a 5 mol / liter aqueous sodium hydroxide solution was added to this solution to adjust the pH to 9.0.
[0173]
Next, an aqueous solution in which 12.1 g of magnesium chloride hexahydrate was dissolved in 1000 ml of ion-exchanged water and 0.7 ml of methyl vinyl ketone were added at 30 ° C. with stirring.
[0174]
After 3 minutes, temperature increase was started, and the system was heated to 90 ° C. over 6 minutes (temperature increase rate = 10 ° C./min). In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II”, and when the number average particle size became 5.5 μm, an aqueous solution in which 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. Was added to stop the particle growth, and the fusion was continued by heating and stirring at a liquid temperature of 85 ° C. for 2 hours as an aging treatment. Then, it cooled to 30 degreeC on the conditions of 8 degreeC / min, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped. The produced association particles are filtered, washed repeatedly with ion exchange water, then dried with hot air at 40 ° C., transferred to a 10 liter Henschel mixer, and added with 0.8% by mass of hydrophobic silica to be mixed with toner. Got. The toner thus obtained is referred to as “toner 1Bk”.
[0175]
Toner 2Bk
A toner was obtained in the same manner except that 2 ml of benzyl methyl ketone was added instead of methyl vinyl ketone in toner 1Bk. The toner thus obtained is referred to as “toner 2Bk”.
[0176]
Toner 3Bk
Toner 1Bk was obtained in the same manner except that ethyl vinyl ketone was added instead of methyl vinyl ketone. The toner thus obtained is referred to as “toner 3Bk”.
[0177]
Toner 4Bk
Instead of latex (1HML) in toner 1Bk, 420.7 g (converted to solid content) of latex (2HL) obtained in Preparation Example 2 was used, and a toner was obtained in the same manner except that 1 ml of methyl vinyl ketone was used. . The toner thus obtained is referred to as “toner 4Bk”.
[0178]
Comparative toner 1Bk
A toner was obtained in the same manner except that 0.1 ml of vinyl ketone was added to toner 1Bk. The toner thus obtained is referred to as “Comparative Toner 1Bk”.
[0179]
Comparative toner 2Bk
A toner was obtained in the same manner except that 20 ml of vinyl ketone was added to toner 1Bk. The toner thus obtained is referred to as “Comparative Toner 2Bk”.
[0180]
Table 1 shows the results of measuring the particle size and shape factor of each toner. Table 2 shows the content of each trace component using the headspace method and the results of evaluation on the following evaluation items.
[0181]
[Table 1]

[0182]
[Table 2]

[0183]
Evaluation (contact development method)
The Konica digital copying machine Konica 7050 was modified to evaluate 5 million shots. As the photoconductor, a laminated organic photoconductor was used.
[0184]
As the fixing method, hot roll fixing was used, and the oil application mechanism and the offset toner cleaning mechanism were removed for evaluation. The top plate of the fixing device housing was made of ABS having a thickness of 3 mm.
[0185]
The image forming conditions were performed in a normal temperature and normal humidity environment (25 ° C./55% RH).
[0186]
<Fixing rate>
Fixing rate is 0.6mg / cm²1 inch square solid images were collected and obtained from image densities before and after peeling with a scotch mending tape (manufactured by Sumitomo 3M).
[0187]
More than 80% pass.
<Deformation of housing>
By visual observation, warping and cracking of the side plate on the fixing device side of the copying machine were observed.
[0188]
<Recycling fuser parts>
If the dimensions of the top plate of the fuser housing at the time of 5 million sheets are within plus or minus 1% from the start of the evaluation, it was judged as “possible” for recycling and “impossible” when there was further deformation.
[0189]
【The invention's effect】
According to the present invention, it is possible to provide a toner having high fixability and prevent deterioration of apparatus parts due to specific volatile components contained in the toner, in particular, deformation and cracking of resin parts around the fuser housing and the fuser. It is possible to provide a heat fixing toner that does not cause resin degradation such as the above, and an image forming method using the same.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating toner particles without corners.
FIG. 2 is a schematic configuration diagram of an image forming apparatus according to the present invention.
FIG. 3 is a cross-sectional view of an example showing the inside of a fixing device according to the present invention.
[Explanation of symbols]
1 Side plate of image forming device
2 Paper cassette
3 Transfer paper (transfer material)
4 Paper feed roller
5 Double feed prevention measures
6 Transport roller
7 Registration roller
8 Photosensitive drum
13 Fixing device
14 Heating roller
15 Pressure roller
20 Resin housing
21 Top plate

Claims (12)

A heat fixing toner comprising at least 0.2-24 ppm of vinyl ketones in a heat fixing toner comprising at least a resin and a colorant. The heat fixing toner according to claim 1, wherein the vinyl ketone component is methyl vinyl ketone. The heat fixing toner according to claim 1, wherein the variation coefficient of the shape factor is 16% or less, and the number variation coefficient in the number particle size distribution is 27% or less. The heat fixing toner according to claim 1, wherein the number of toner particles having a shape factor in the range of 1.0 to 1.6 is 65% by number or more. The heat fixing toner according to claim 1, wherein the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more. The toner for thermal fixing according to claim 1, wherein the toner particles having no corners are 50% by number or more. The heat fixing toner according to claim 1, wherein the number average particle diameter is 2 to 8 μm. When the particle diameter of the toner particles is D (μm), the horizontal axis represents the natural logarithm lnD, and the histogram shows the number-based particle size distribution divided into a plurality of classes at intervals of 0.23. The sum (M) of the relative frequency (m1) of the toner particles contained in the class and the relative frequency (m2) of the toner particles contained in the next most frequent class after the most frequent class is 70% or more. The heat fixing toner according to claim 1, wherein the toner is heat fixing. The heat fixing toner according to any one of claims 1 to 8, wherein the toner is produced by polymerizing a polymerizable monomer in an aqueous medium. The heat fixing toner according to claim 1, wherein the toner particles are obtained by salting out / fusion-bonding resin particles in an aqueous medium. A toner obtained by salting out / fusion-bonding composite resin particles obtained by a multistage polymerization method and colorant particles, and containing a release agent in a region other than the outermost layer of the composite resin particles The heat fixing toner according to claim 1, wherein the toner is a heat fixing toner. The electrostatic latent image is developed using a toner composed of at least a resin and a colorant and containing 0.2 to 24 ppm of a vinyl ketone component having 4 to 24 carbon atoms, and is heat-fixed after being transferred onto a transfer material. An image forming method.

Images