JP4172161B2 - Image forming method and image forming apparatus - Google Patents

Description

【００７８】
と示される。
この固着率は２５％以上１００％未満が好ましい。特に、４０〜８０％が好ましい。固着率が２５％未満であると樹脂粒子に対する無機微粒子の固着程度が低くなり、表面に存在する無機微粒子の遊離が発生する。このため、長期に亘って使用を繰り返すと無機微粒子の遊離により感光体に対する傷の問題を発生する。固着率の調整は固着を行う製造装置に於いてその条件を種々に制御することで行うことができる。
【００７９】
なお、オーダードミクスチャーを形成する場合、本発明では樹脂粒子の表面を構成する樹脂のガラス転移温度Ｔｇ以下の雰囲気温度で作製するとよい。すなわち、Ｔｇ以上の温度でオーダードミクスチャーを形成した場合は、樹脂粒子の合一が発生するためである。
【００８０】
複合粒子を構成する無機微粒子と核となる樹脂粒子との比率はそれぞれの粒径に依存し、核となる樹脂粒子を均一に覆うだけ無機微粒子を添加すればよい。一般には、樹脂粒子に対して無機微粒子が５〜３０質量％が好ましい。
【００８１】
なお、オーダードミクスチャーを形成する場合には核となる樹脂粒子表面に均一に静電気的に無機微粒子を付着することのできる装置であれば全て使用することができる。例えば、ヘンシェルミキサー、ＯＭダイザー、タービュラーミキサー、レーディゲミキサー、Ｖ型混合器等をあげることができる。
【００８２】
表面に静電気的に付着した無機微粒子を固着させるための機械的エネルギー付与装置としては、衝撃式粉砕機を改造した「ハイブリダイザー」（奈良機械製作所製）、「自由ミル」（奈良機械製作所製）、「オングミル」（ホソカワミクロン社製）、「クリプトロン」（川崎重工社製）等を使用することができる。本装置を用いて樹脂粒子表面に無機微粒子を固着する場合には単なる機械的エネルギーを付与するのみならず、外部より加温あるいは冷却することも可能である。すわなわち、高速度で回転する装置内で機械的衝撃力を付与すると、その衝突のエネルギーによって発熱がおこり内部の温度は上昇する。樹脂粒子のＴｇよりも高い温度に装置内部がなった場合には、樹脂粒子の内部に対する融着を発生し、凝集粒子を発生する問題がある。このためには冷却を行い制御することが必要となる。一方で内部の温度がＴｇよりも３０℃以上低い場合には固着するためのエネルギーが過多に必要となり、衝突エネルギーが大きくなり、樹脂粒子の粉砕等の問題を発生する。この問題を解消するためには温度をＴｇ程度にまで上昇する必要があり、この場合には外部から加温することが必要となる。
【００８３】
外部から温度を制御する方法としては加温された媒体を外部に設置したジャケットに循環し、制御する方法が好ましい。内部の温度は樹脂粒子と無機微粒子を固着するための部位に設置された温度計により測定された循環空気の温度により測定される。なお、循環するための媒体としては水あるいはオイルがある。
【００８４】
複合粒子の帯電量は、絶対値で１〜４０μＣ／ｇが好ましい。この帯電量の制御は表面に固着する無機微粒子の帯電性を制御すること及び核となる樹脂粒子の帯電性を制御することよって行うことができる。
【００８５】
尚、複合粒子の数平均粒径は１００〜２０００ｎｍの範囲が好ましく、更に２００〜１２００ｎｍの範囲が最も好ましく用いられる。１００ｎｍ未満だとクリーニングブレードのトナーや感光体に対する緩衝効果が小さくフィルミング等の発生防止効果が小さい。又、２０００ｎｍより大きいと複合粒子がトナーから遊離してしまう問題があり、飛散した粒子により帯電極の汚染や転写極の汚染が引き起こされ、白スジ等の画像欠陥を引き起こす原因となる。又複合粒子の添加量はトナー中に０．１〜５．０質量％が好ましい（ここで、トナーの総質量は複合粒子や後記する微粒子を含めた総質量を指す）。特に好ましくは０．２〜３．０質量％であり、最も好ましくは０．４〜１．５質量％である。
【００８６】
以下に複合粒子の作製例を示す。
数平均一次粒子径が０．３μｍのスチレン／アクリル樹脂粒子（メチルメタクリレート：スチレンが９：１）を使用し、無機微粒子としてオクチルトリメトキシシランにて疎水化処理を行った酸化チタン１（数平均一次粒子径＝１５ｎｍ）を使用した。樹脂粒子１００質量部に対して無機微粒子１７質量部を添加し、ＯＭダイザー（奈良機械製作所製）へ投入し、無機微粒子と樹脂粒子が混合されている装置の外部より媒体として３０℃の循環水を流しながら５００ｒｐｍにて３分混合した。混合時に於ける品温は３０℃であった。得られたオーダードミクスチャーは走査型電子顕微鏡によって観察すると樹脂粒子表面に無機微粒子は均一に静電気的に付着していることが分かった。
【００８７】
次いでこのオーダードミクスチャーをハイブリダイザー（奈良機械製作所製）へ投入し、無機微粒子と樹脂粒子に繰り返し機械的衝撃力が付与される装置の外部より媒体として４５℃の循環水で加温しながら周速１００ｍ／ｓｅｃの条件で３分処理し本発明の複合粒子を得た。なお、内部の温度（品温）は５６℃であった。さらに、機械内部の付着の状態を観察したが、特に付着が無く良好であった。また、樹脂粒子の合一物も存在していないことが走査型電子顕微鏡観察によって確認された。
【００８８】
又、上記複合粒子と共に、５〜４９ｎｍの微粒子の流動化剤を併用することが好ましい。このような流動化剤として好ましく用いられるものはシリカ、アルミナ、チタニア、ジルコニア等である。
【００８９】
上記流動化剤の添加量はトナー中に０．１〜３．０質量％、好ましくは０．３〜２．５質量％である。この範囲を越えて添加すると、微粒子自体が遊離してしまう問題があり、飛散した粒子により帯電極の汚染や転写極の汚染が引き起こされ、白スジ等の画像欠陥を引き起こす原因となる。さらには微粒子が遊離した状態でトナー中に存在しているために、感光体に対して傷を誘発する原因となり、感光体に傷をつけ、いわゆる黒ポチや白ポチを誘発する。また、過小の場合には、トナーの流動性が不十分となり、良好な画像を形成しにくい。
【００９０】
上記粒径は、数平均一次粒子径であり、透過型電子顕微鏡観察によって２０００倍に拡大し、１００個の粒子を観察し、画像解析によって測定されたものを示す。
【００９１】
又、上記複合粒子の無機微粒子や流動化剤は疎水化処理が行われたものが好ましい。疎水化処理を行う場合には、各種チタンカップリング剤、シランカップリング剤等のいわゆるカップリング剤やシリコーンオイル等によって疎水化処理することが好ましく、さらに、ステアリン酸アルミニウム、ステアリン酸亜鉛、ステアリン酸カルシウム等の高級脂肪酸金属塩によって疎水化処理することも好ましく使用される。
【００９２】
上記微粒子外添剤の他に本発明のトナーには滑剤を添加することもできる。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。これら滑剤の添加量は、トナーに対して０．１〜５質量％程度が好ましい。
〔トナー化工程〕
外添剤の添加方法としては、タービュラーミキサー、ヘンシェルミキサー、ナウターミキサー、Ｖ型混合機などの種々の公知の混合装置を使用することができる。
【００９３】
トナーは、着色剤、離型剤以外にトナー用材料として種々の機能を付与することのできる材料を加えてもよい。具体的には荷電制御剤等が挙げられる。これらの成分は外添剤を添加する前のトナー（着色粒子とも云う）の段階で着色粒子の製造段階で添加することが出来る。該着色粒子は従来の粉砕法により作製しても良く、重合法により作製してもよい。
【００９４】
粉砕法で着色粒子を作製する場合は離型剤や荷電制御剤は樹脂と顔料の混練段階で添加できる。一方、重合法で作製する場合は樹脂重合の段階で添加する方法、樹脂粒子作製後の樹脂粒子凝集段階で顔料等と同時に添加する方法等が挙げられる。
【００９５】
尚、重合法での離型剤としては、種々の公知のもので、且つ水中に分散することができるものを使用することが好ましい。具体的には、ポリプロピレン、ポリエチレン等のオレフィン系ワックスや、これらの変性物、カルナウバワックスやライスワックス等の天然ワックス、脂肪酸ビスアミドなどのアミド系ワックスなどをあげることができる。これらは離型剤粒子として加えられ、樹脂や着色剤と共に塩析／融着させることが好ましいことはすでに述べた。
【００９６】
又重合法での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。
【００９７】
これら離型剤や荷電制御剤の粒子は、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。
【００９８】
以下、本発明で好ましく用いられる重合法によるトナー（着色粒子）について記載する。
【００９９】
本発明に適用されるトナーとしては、個々のトナー粒子の粒度分布、及び形状が比較的均一な重合トナーが好ましい。ここで、重合トナーとはトナー用バインダーの樹脂の生成とトナー形状が、バインダー樹脂の原料モノマーの重合及びその後の化学的処理により形成されて得られるトナーを意味する。より具体的には懸濁重合、乳化重合等の重合反応と必要により該重合反応後に行われる粒子同志の融着工程を経て得られるトナーを意味する。
【０１００】
本発明に用いられる重合トナーとしては特定の形状を有するトナーが好ましい。以下、本発明に好ましく用いることのできる重合トナーについて記載する。
【０１０１】
本発明に適用される好ましい重合トナーとしては、形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上であり、形状係数の変動係数が１６％以下であるトナーを使用することである。このような特性の重合トナーを使用すると、クリーニングブレードの振動を安定させることができ、優れたクリーニング性能を発揮することを見出した。
【０１０２】
又、クリーニングブレードの振動の安定性は、トナー粒子の粒径によっても異なり、粒子径の小さいものの方が像担持体への付着力が高いために、振動が過大となりやすく、且つトナーがクリーニングブレードをすり抜ける確率が高い。しかしながら、トナー粒子径が大きいものでは、このようなすり抜けは減少するが、解像度等の画質が低下する問題が発生する。
【０１０３】
以上の観点より検討を加えた結果、トナーの形状係数の変動係数が１６％以下であり、且つトナーの個数粒度分布における個数変動係数が２７％以下であるトナーを使用することにより、クリーニング性、細線再現性に優れ、高品位な画質を長期にわたって形成することができることを見出した。
【０１０４】
また、角がないトナー粒子を５０個数％以上とし、個数粒度分布における個数変動係数を２７％以下に制御したものを使用することにより、クリーニング性、細線再現性に優れ、高品位な画質を長期にわたって形成することができる。
【０１０５】
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。
【０１０６】
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。
【０１０７】
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。
【０１０８】
重合トナーとしては、この形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上が好ましく、より好ましくは、７０個数％以上である。
【０１０９】
この形状係数が１．２〜１．６の範囲にあるトナー粒子が６５個数％以上であることにより、現像剤搬送部材などでの摩擦帯電性がより均一となり、過度に帯電したトナーの蓄積が無く、現像剤搬送部材表面よりトナーがより交換しやすくなるために、現像ゴースト等の問題も発生しにくくなる。さらに、トナー粒子が破砕しにくくなって帯電付与部材の汚染が減少し、トナーの帯電性が安定する。
【０１１０】
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１．２〜１．６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整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同様に通常のトナーへ添加して調整する方法がある。
【０１１１】
重合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。〕
この形状係数の変動係数は１６％以下が好ましく、更に好ましくは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。
【０１１２】
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。
【０１１３】
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。
【０１１４】
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（東亜医用電子社製）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。
【０１１５】
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。
【０１１６】
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。〕
トナーの個数変動係数は２７％以下でありが好ましく、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。
【０１１７】
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。
【０１１８】
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水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。
【０１１９】
角がないトナー粒子とは、電荷の集中するような突部またはストレスにより摩耗しやすいような突部を実質的に有しないトナー粒子を言い、すなわち、図３（ａ）に示すように、トナー粒子Ｔの長径をＬとするときに、半径（Ｌ／１０）の円Ｃで、トナー粒子Ｔの周囲線に対し１点で内側に接しつつ内側をころがした場合に、当該円ＣがトナーＴ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箇所以下である場合をいう。また、「トナー粒子の長径」とは、当該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。なお、図３（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示している。
【０１２０】
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。
【０１２１】
角がないトナー粒子の割合は５０個数％以上が好ましく、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。
【０１２２】
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。
【０１２３】
また、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、攪拌翼の回転数および攪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。
【０１２４】
本発明のトナーの粒径は、個数平均粒径で３〜８μｍ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。
【０１２５】
個数平均粒径が３〜８μｍ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。
【０１２６】
本発明に好ましく用いられる重合トナーとしては、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。
【０１２７】
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。
【０１２８】
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。
【０１２９】
〔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）を適量加えて攪拌し、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。
【０１３０】
形状係数を制御する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。
【０１３１】
重合トナーは、懸濁重合法や、必要な添加剤の乳化液を加えた液中にて単量体を乳化重合し、微粒の重合粒子を製造し、その後に、有機溶媒、凝集剤等を添加して会合する方法で製造することができる。会合の際にトナーの構成に必要な離型剤や着色剤などの分散液と混合して会合させて調製する方法や、単量体中に離型剤や着色剤などのトナー構成成分を分散した上で乳化重合する方法などがあげられる。ここで会合とは樹脂粒子および着色剤粒子が複数個融着することを示す。
【０１３２】
即ち、重合性単量体中に着色剤や必要に応じて離型剤、荷電制御剤、さらに重合開始剤等の各種構成材料を添加し、ホモジナイザー、サンドミル、サンドグラインダー、超音波分散機などで重合性単量体に各種構成材料を溶解あるいは分散させる。この各種構成材料が溶解あるいは分散された重合性単量体を分散安定剤を含有した水系媒体中にホモミキサーやホモジナイザーなどを使用しトナーとしての所望の大きさの油滴に分散させる。その後、攪拌機構が後述の攪拌翼である反応装置へ移し、加熱することで重合反応を進行させる。反応終了後、分散安定剤を除去し、濾過、洗浄し、さらに乾燥することでトナーを調製する。
【０１３３】
また、本発明のトナーを製造する方法として樹脂粒子を水系媒体中で会合あるいは融着させて調製する方法も挙げることができる。この方法としては、特に限定されるものではないが、例えば、特開平５−２６５２５２号公報や特開平６−３２９９４７号公報、特開平９−１５９０４号公報に示す方法を挙げることができる。すなわち、樹脂粒子と着色剤などの構成材料の分散粒子、あるいは樹脂および着色剤等より構成される微粒子を複数以上会合させる方法、特に水中にてこれらを乳化剤を用いて分散した後に、臨界凝集濃度以上の凝集剤を加え塩析させると同時に、形成された重合体自体のガラス転移点温度以上で加熱融着させて融着粒子を形成しつつ徐々に粒径を成長させ、目的の粒径となったところで水を多量に加えて粒径成長を停止し、さらに加熱、攪拌しながら粒子表面を平滑にして形状を制御し、その粒子を含水状態のまま流動状態で加熱乾燥することにより、トナーを形成することができる。なお、ここにおいて凝集剤と同時に水に対して無限溶解する有機溶媒を加えてもよい。
【０１３４】
なお、本発明でいうところの水系媒体とは、少なくとも水が５０質量％以上含有されたものを示す。
【０１３５】
樹脂を構成する重合性単量体として使用されるものは、スチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、α−メチルスチレン、ｐ−クロロスチレン、３，４−ジクロロスチレン、ｐ−フェニルスチレン、ｐ−エチルスチレン、２，４−ジメチルスチレン、ｐ−ｔｅｒｔ−ブチルスチレン、ｐ−ｎ−ヘキシルスチレン、ｐ−ｎ−オクチルスチレン、ｐ−ｎ−ノニルスチレン、ｐ−ｎ−デシルスチレン、ｐ−ｎ−ドデシルスチレンの様なスチレンあるいはスチレン誘導体、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ｎ−ブチル、メタクリル酸イソプロピル、メタクリル酸イソブチル、メタクリル酸ｔ−ブチル、メタクリル酸ｎ−オクチル、メタクリル酸２−エチルヘキシル、メタクリル酸ステアリル、メタクリル酸ラウリル、メタクリル酸フェニル、メタクリル酸ジエチルアミノエチル、メタクリル酸ジメチルアミノエチル等のメタクリル酸エステル誘導体、アクリル酸メチル、アクリル酸エチル、アクリル酸イソプロピル、アクリル酸ｎ−ブチル、アクリル酸ｔ−ブチル、アクリル酸イソブチル、アクリル酸ｎ−オクチル、アクリル酸２−エチルヘキシル、アクリル酸ステアリル、アクリル酸ラウリル、アクリル酸フェニル等の、アクリル酸エステル誘導体、エチレン、プロピレン、イソブチレン等のオレフィン類、塩化ビニル、塩化ビニリデン、臭化ビニル、フッ化ビニル、フッ化ビニリデン等のハロゲン系ビニル類、プロピオン酸ビニル、酢酸ビニル、ベンゾエ酸ビニル等のビニルエステル類、ビニルメチルエーテル、ビニルエチルエーテル等のビニルエーテル類、ビニルメチルケトン、ビニルエチルケトン、ビニルヘキシルケトン等のビニルケトン類、Ｎ−ビニルカルバゾール、Ｎ−ビニルインドール、Ｎ−ビニルピロリドン等のＮ−ビニル化合物、ビニルナフタレン、ビニルピリジン等のビニル化合物類、アクリロニトリル、メタクリロニトリル、アクリルアミド等のアクリル酸あるいはメタクリル酸誘導体がある。これらビニル系単量体は単独あるいは組み合わせて使用することができる。
【０１３６】
また、樹脂を構成する重合性単量体としてイオン性解離基を有するものを組み合わせて用いることがさらに好ましい。例えば、カルボキシル基、スルフォン酸基、リン酸基等の置換基を単量体の構成基として有するもので、具体的には、アクリル酸、メタクリル酸、マレイン酸、イタコン酸、ケイ皮酸、フマール酸、マレイン酸モノアルキルエステル、イタコン酸モノアルキルエステル、スチレンスルフォン酸、アリルスルフォコハク酸、２−アクリルアミド−２−メチルプロパンスルフォン酸、アシッドホスホオキシエチルメタクリレート、３−クロロ−２−アシッドホスホオキシプロピルメタクリレート等が挙げられる。
【０１３７】
さらに、ジビニルベンゼン、エチレングリコールジメタクリレート、エチレングリコールジアクリレート、ジエチレングリコールジメタクリレート、ジエチレングリコールジアクリレート、トリエチレングリコールジメタクリレート、トリエチレングリコールジアクリレート、ネオペンチルグリコールジメタクリレート、ネオペンチルグリコールジアクリレート等の多官能性ビニル類を使用して架橋構造の樹脂とすることもできる。
【０１３８】
これら重合性単量体はラジカル重合開始剤を用いて重合することができる。この場合、懸濁重合法では油溶性重合開始剤を用いることができる。この油溶性重合開始剤としては、２，２′−アゾビス−（２，４−ジメチルバレロニトリル）、２，２′−アゾビスイソブチロニトリル、１，１′−アゾビス（シクロヘキサン−１−カルボニトリル）、２，２′−アゾビス−４−メトキシ−２，４−ジメチルバレロニトリル、アゾビスイソブチロニトリル等のアゾ系またはジアゾ系重合開始剤、ベンゾイルパーオキサイド、メチルエチルケトンペルオキサイド、ジイソプロピルペルオキシカーボネート、クメンヒドロペルオキサイド、ｔ−ブチルヒドロペルオキサイド、ジ−ｔ−ブチルペルオキサイド、ジクミルペルオキサイド、２，４−ジクロロベンゾイルペルオキサイド、ラウロイルペルオキサイド、２，２−ビス−（４，４−ｔ−ブチルペルオキシシクロヘキシル）プロパン、トリス−（ｔ−ブチルペルオキシ）トリアジンなどの過酸化物系重合開始剤や過酸化物を側鎖に有する高分子開始剤などを挙げることができる。
【０１３９】
また、乳化重合法を用いる場合には水溶性ラジカル重合開始剤を使用することができる。水溶性重合開始剤としては、過硫酸カリウム、過硫酸アンモニウム等の過硫酸塩、アゾビスアミノジプロパン酢酸塩、アゾビスシアノ吉草酸およびその塩、過酸化水素等を挙げることができる。
【０１４０】
分散安定剤としては、リン酸三カルシウム、リン酸マグネシウム、リン酸亜鉛、リン酸アルミニウム、炭酸カルシウム、炭酸マグネシウム、水酸化カルシウム、水酸化マグネシウム、水酸化アルミニウム、メタケイ酸カルシウム、硫酸カルシウム、硫酸バリウム、ベントナイト、シリカ、アルミナ等を挙げることができる。さらに、ポリビニルアルコール、ゼラチン、メチルセルロース、ドデシルベンゼンスルフォン酸ナトリウム、エチレンオキサイド付加物、高級アルコール硫酸ナトリウム等の界面活性剤として一般的に使用されているものを分散安定剤として使用することができる。
【０１４１】
本発明において優れた樹脂としては、ガラス転移点が２０〜９０℃のものが好ましく、軟化点が８０〜２２０℃のものが好ましい。ガラス転移点は示差熱量分析方法で測定されるものであり、軟化点は高化式フローテスターで測定することができる。さらに、これら樹脂としては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る分子量が数平均分子量（Ｍｎ）で１０００〜１０００００、重量平均分子量（Ｍｗ）で２０００〜１００００００のものが好ましい。さらに、分子量分布として、Ｍｗ／Ｍｎが１．５〜１００、特に１．８〜７０のものが好ましい。
【０１４２】
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。
【０１４３】
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。
【０１４４】
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。
【０１４５】
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、ｔ−ブタノール、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。
【０１４６】
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。
【０１４７】
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はかられやすいものと考えられる。
【０１４８】
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。
【０１４９】
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。
【０１５０】
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。
【０１５１】
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。
【０１５２】
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。
【０１５３】
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。
【０１５４】
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。
【０１５５】
いわゆる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。すなわち、形状係数が１．２以上の形状を有するトナー粒子を多く形成させる場合には、反応容器中での媒体の流れを乱流とし、重合が進行して懸濁状態で水系媒体中に存在している油滴が次第に高分子化することで油滴が柔らかい粒子となった時点で、粒子の衝突を行うことで粒子の合一を促進させ、形状が不定形となった粒子が得られる。また、形状係数が１．２より小さい球形のトナー粒子を形成させる場合には、反応容器中での媒体の流れを層流として、粒子の衝突を避けることにより球形の粒子が得られる。この方法により、トナー形状の分布を本発明の範囲内に制御できるものである。以下、本発明に好ましく用いられる重合トナーの反応装置について記載する。
【０１５６】
まず、重合トナーの製造に好ましく用いられる反応装置について説明する。図４および図５は、それぞれ、重合トナー反応装置の一例を示す斜視図および断面図である。図４および図５に示す反応装置において、熱交換用のジャケット１を外周部に装着した縦型円筒状の攪拌槽２内の中心部に回転軸３を垂設し、該回転軸３に攪拌槽２の底面に近接させて配設された下段の攪拌翼４０と、より上段に配設された攪拌翼５０とが設けられている。上段の攪拌翼５０は、下段に位置する攪拌翼４０に対して回転方向に先行した交差角αをもって配設されている。本発明のトナーを製造する場合において、交差角αは９０度（°）未満であることが好ましい。この交差角αの下限は特に限定されるものでは無いが、５°程度以上であることが好ましく、更に、好ましくは１０°以上である。なお、三段構成の攪拌翼を設ける場合には、それぞれ隣接している攪拌翼間で交差角αが９０度未満であることが好ましい。
【０１５７】
このような構成とすることで、上段に配設されている攪拌翼５０によりまず媒体が攪拌され、下側への流れが形成される。ついで、下段に配設された攪拌翼４０により、上段の攪拌翼５０で形成された流れがさらに下方へ加速されるとともにこの攪拌翼５０自体でも下方への流れが別途形成され、全体として流れが加速されて進行するものと推定される。この結果、乱流として形成された大きなズリ応力を有する流域が形成されるために、得られるトナー粒子の形状を制御できるものと推定される。
【０１５８】
なお、図４および図５中、矢印は回転方向を示し、７は上部材料投入口、８は下部材料投入口、９は攪拌を有効にするための乱流形成部材である。
【０１５９】
ここにおいて攪拌翼の形状については、特に限定はないが、方形板状のもの、翼の一部に切り欠きのあるもの、中央部に一つ以上の中孔部分、いわゆるスリットがあるものなどを使用することができる。これらの具体例を図６に記載する。図６（ａ）に示す攪拌翼５ａは中孔部のないもの、同図（ｂ）に示す攪拌翼５ｂは中央に大きな中孔部６ｂがあるもの、同図（ｃ）に示す攪拌翼５ｃは横長の中孔部６ｃ（スリット）があるもの、同図（ｄ）に示す攪拌翼５ｄは縦長の中孔部６ｄ（スリット）があるものである。また、三段構成の攪拌翼を設ける場合において、上段の攪拌翼に形成される中孔部と、下段の攪拌翼に形成される中孔部とは異なるものであっても、同一のものであってもよい。
【０１６０】
なお、上記の構成を有する上段と下段の攪拌翼の間隙は特に限定されるものでは無いが、少なくとも攪拌翼の間に間隙を有していることが好ましい。この理由としては明確では無いが、その間隙を通じて媒体の流れが形成されるため、攪拌効率が向上するものと考えられる。但し、間隙としては、静置状態での液面高さに対して０．５〜５０％の幅、好ましくは１〜３０％の幅である。
【０１６１】
さらに、攪拌翼の大きさは特に限定されるものでは無いが、全攪拌翼の高さの総和が静置状態での液面高さの５０％〜１００％、好ましくは６０％〜９５％である。
【０１６２】
一方、樹脂粒子を水系媒体中で会合あるいは融着させる重合法トナーでは、融着段階での反応容器内の媒体の流れおよび温度分布を制御することで、さらには融着後の形状制御工程において加熱温度、攪拌回転数、時間を制御することで、トナー全体の形状分布および形状を任意に変化させることができる。
【０１６３】
すなわち、樹脂粒子を会合あるいは融着させる重合法トナーでは、反応装置内の流れを層流とし、内部の温度分布を均一化することができる攪拌翼および攪拌槽を使用して、融着工程および形状制御工程での温度、回転数、時間を制御することにより、所期の形状係数および均一な形状分布を有するトナーを形成することができる。この理由は、層流を形成させた場で融着させると、凝集および融着が進行している粒子（会合あるいは凝集粒子）に強いストレスが加わらず、かつ流れが加速された層流においては攪拌槽内の温度分布が均一である結果、融着粒子の形状分布が均一になるからであると推定される。さらに、その後の形状制御工程での加熱、攪拌により融着粒子は徐々に球形化し、トナー粒子の形状を任意に制御できる。
【０１６４】
樹脂粒子を会合あるいは融着させる重合法トナーを製造する際に使用される攪拌槽としては、前述の懸濁重合法と同様のものが使用できる。この場合、攪拌槽内には乱流を形成させるような邪魔板等の障害物を設けないことが必要である。
【０１６５】
この攪拌翼の形状についても、層流を形成させ、乱流を形成させないものであれば特に限定されないが、図６（ａ）に示した方形板状のもの等、連続した面により形成されるものが好ましく、曲面を有していてもよい。
《現像剤》
本発明に用いられるトナーは、一成分現像剤でも二成分現像剤でもよいが、好ましくは二成分現像剤である。
【０１６６】
一成分現像剤として用いる場合は、非磁性一成分現像剤として前記トナーをそのまま用いる方法もあるが、通常はトナー粒子中に０．１〜５μｍ程度の磁性粒子を含有させ磁性一成分現像剤として用いる。その含有方法としては、着色剤と同様にして非球形粒子中に含有させるのが普通である。
【０１６７】
又、キャリアと混合して二成分現像剤として用いることができる。この場合は、キャリアの磁性粒子として、鉄、フェライト、マグネタイト等の金属、それらの金属とアルミニウム、鉛等の金属との合金等の従来から公知の材料を用いる。特にフェライト粒子が好ましい。上記磁性粒子は、その体積平均粒径としては１５〜１００μｍ、より好ましくは２５〜６０μｍのものがよい。
【０１６８】
キャリアの体積平均粒径の測定は、代表的には湿式分散機を備えたレーザ回折式粒度分布測定装置「ヘロス（ＨＥＬＯＳ）」（シンパティック（ＳＹＭＰＡＴＥＣ）社製）により測定することができる。
【０１６９】
キャリアは、磁性粒子が更に樹脂により被覆されているもの、あるいは樹脂中に磁性粒子を分散させたいわゆる樹脂分散型キャリアが好ましい。コーティング用の樹脂組成としては、特に限定は無いが、例えば、オレフィン系樹脂、スチレン系樹脂、スチレン／アクリル系樹脂、シリコーン系樹脂、エステル系樹脂或いはフッ素含有重合体系樹脂等が用いられる。また、樹脂分散型キャリアを構成するための樹脂としては、特に限定されず公知のものを使用することができ、例えば、スチレンアクリル樹脂、ポリエステル樹脂、フッ素系樹脂、フェノール樹脂等を使用することができる。
【０１７０】
【実施例】
以下、実施例をあげて本発明を詳細に説明するが、本発明の様態はこれに限定されない。なお、文中「部」とは「質量部」を表す。
【０１７１】
実施例に用いる感光体として以下の感光体を作製した。
感光体１の作製
〈下引き層〉
チタンキレート化合物（ＴＣ−７５０：松本製薬製） ３０ｇ
シランカップリング剤（ＫＢＭ−５０３：信越化学社製） １７ｇ
２−プロパノール １５０ｍｌ
上記塗布液を用いてφ１００ｍｍの円筒形の導電性支持体上に、乾燥膜厚０．５μｍとなるよう塗布した。
【０１７２】
〈電荷発生層〉
Ｙ型チタニルフタロシアニン（Ｃｕ−Ｋα特性Ｘ線によるＸ線回折の最大ピーク角度が２θで２７．３） ６０ｇ
シリコーン変性ブチラール樹脂（Ｘ−４０−１２１１Ｍ：信越化学社製）７００ｇ
２−ブタノン ２０００ｍｌ
を混合し、サンドミルを用いて１０時間分散し、電荷発生層塗布液を調製した。この塗布液を前記下引き層の上に浸漬塗布法で塗布し、乾燥膜厚０．２μｍの電荷発生層を形成した。
【０１７３】
〈電荷輸送層〉
電荷輸送物質〔Ｎ−（４−メチルフェニル）−Ｎ−｛４−
（β−フェニルスチリル）フェニル｝−ｐ−トルイジン〕 ２２５ｇ
ポリカーボネート（粘度平均分子量３０，０００） ３００ｇ
酸化防止剤（サノールＬＳ２６２６：三共社製） ６ｇ
ジクロロメタン ２０００ｍｌ
を混合し、溶解して電荷輸送層塗布液を調製した。この塗布液を前記電荷発生層の上に浸漬塗布法で塗布し、乾燥膜厚２０μｍの電荷輸送層を形成し感光体１を作製した。
【０１７４】
感光体２の作製
感光体１の電荷輸送層のポリカーボネートを粘度平均分子量８０，０００のポリカーボネートに代えた以外は感光体１と同様にして感光体２を作製した。
【０１７５】
以下に本発明に用いるトナーを作製した。
着色粒子１、２の作製（乳化重合法の例）
ｎ−ドデシル硫酸ナトリウム０．９０ｋｇと純水１０．０ｌを入れ攪拌溶解する。この溶液に、リーガル３３０Ｒ（キャボット社製カーボンブラック）１．２０ｋｇを徐々に加え、１時間よく攪拌した後に、サンドグラインダー（媒体型分散機）を用いて、２０時間連続分散した。このものを「着色剤分散液１」とする。また、ドデシルベンゼンスルホン酸ナトリウム０．０５５ｋｇとイオン交換水４．０ｌからなる溶液を「アニオン界面活性剤溶液Ａ」とする。
【０１７６】
ノニルフェノールポリエチレンオキサイド１０モル付加物０．０１４ｋｇとイオン交換水４．０ｌからなる溶液を「ノニオン界面活性剤溶液Ｂ」とする。過硫酸カリウム２２３．８ｇをイオン交換水１２．０ｌに溶解した溶液を「開始剤溶液Ｃ」とする。
【０１７７】
温度センサー、冷却管、窒素導入装置を付けた１００ｌのＧＬ（グラスライニング）反応釜に、ＷＡＸエマルジョン（数平均分子量３０００のポリプロピレンエマルジョン：数平均一次粒子径＝１２０ｎｍ／固形分濃度＝２９．９％）３．４１ｋｇと「アニオン界面活性剤溶液Ａ」全量と「ノニオン界面活性剤溶液Ｂ」全量とを入れ、攪拌を開始する。次いで、イオン交換水４４．０ｌを加える。
【０１７８】
加熱を開始し、液温度が７５℃になったところで、「開始剤溶液Ｃ」全量を滴下して加えた。その後、液温度を７５℃±１℃に制御しながら、スチレン１２．１ｋｇとアクリル酸ｎ−ブチル２．８８ｋｇとメタクリル酸１．０４ｋｇとｔ−ドデシルメルカプタン５４８ｇとを滴下しながら投入する。滴下終了後、液温度を８０℃±１℃に上げて、６時間加熱攪拌を行った。ついで、液温度を４０℃以下に冷却し攪拌を停止し、ポールフィルターで濾過し、これを「ラテックス▲１▼−Ａ」とする。
【０１７９】
なお、ラテックス▲１▼−Ａ中の樹脂粒子のガラス転移温度は５７℃、軟化点は１２１℃、分子量分布は、重量平均分子量＝１．２７万、重量平均粒径は１２０ｎｍであった。
【０１８０】
また、ドデシルベンゼンスルホン酸ナトリウム０．０５５ｋｇをイオン交換純水４．０ｌに溶解した溶液を「アニオン界面活性剤溶液Ｄ」とする。また、ノニルフェノールポリエチレンオキサイド１０モル付加物０．０１４ｋｇをイオン交換水４．０ｌに溶解した溶液を「ノニオン界面活性剤溶液Ｅ」とする。
【０１８１】
過硫酸カリウム（関東化学社製）２００．７ｇをイオン交換水１２．０ｌに溶解した溶液を「開始剤溶液Ｆ」とする。
【０１８２】
温度センサー、冷却管、窒素導入装置、櫛形バッフルを付けた１００ｌのＧＬ反応釜に、ＷＡＸエマルジョン（数平均分子量３０００のポリプロピレンエマルジョン：数平均一次粒子径＝１２０ｎｍ／固形分濃度２９．９％）３．４１ｋｇと「アニオン界面活性剤溶液Ｄ」全量と「ノニオン界面活性剤溶液Ｅ」全量とを入れ、攪拌を開始する。次いで、イオン交換水４４．０ｌを投入する。加熱を開始し、液温度が７０℃になったところで、「開始剤溶液Ｆ」を添加する。ついで、スチレン１１．０ｋｇとアクリル酸ｎ−ブチル４．００ｋｇとメタクリル酸１．０４ｋｇとｔ−ドデシルメルカプタン９．０２ｇとをあらかじめ混合した溶液を滴下する。滴下終了後、液温度を７２℃±２℃に制御して、６時間加熱攪拌を行った。さらに、液温度を８０℃±２℃に上げて、１２時間加熱攪拌を行った。液温度を４０℃以下に冷却し攪拌を停止する。ポールフィルターで濾過し、この濾液を「ラテックス▲１▼−Ｂ」とした。
【０１８３】
なお、ラテックス▲１▼−Ｂ中の樹脂粒子のガラス転移温度は５８℃、軟化点は１３２℃、分子量分布は、重量平均分子量＝２４．５万、重量平均粒径は１１０ｎｍであった。
【０１８４】
塩析剤としての塩化ナトリウム５．３６ｋｇをイオン交換水２０．０ｌに溶解した溶液を「塩化ナトリウム溶液Ｇ」とする。
【０１８５】
フッ素系ノニオン界面活性剤１．００ｇをイオン交換水１．００ｌに溶解した溶液を「ノニオン界面活性剤溶液Ｈ」とする。
【０１８６】
温度センサー、冷却管、窒素導入装置、粒径および形状のモニタリング装置を付けた１００ｌのＳＵＳ反応釜に、上記で作製したラテックス▲１▼−Ａ＝２０．０ｋｇとラテックス▲１▼−Ｂ＝５．２ｋｇと着色剤分散液１＝０．４ｋｇとイオン交換水２０．０ｋｇとを入れ攪拌する。ついで、４０℃に加温し、塩化ナトリウム溶液Ｇ、イソプロパノール（関東化学社製）６．００ｋｇ、ノニオン界面活性剤溶液Ｈをこの順に添加する。その後、１０分間放置した後に、昇温を開始し、液温度８５℃まで６０分で昇温し、８５±２℃にて０．５〜３時間加熱攪拌して塩析／融着させながら粒径成長させる。次に純水２．１ｌを添加して粒径成長を停止する。
【０１８７】
温度センサー、冷却管、粒径および形状のモニタリング装置を付けた５ｌの反応容器に、上記で作製した融着粒子分散液５．０ｋｇを入れ、液温度８５℃±２℃にて、０．５〜１５時間加熱攪拌して形状制御した。その後、４０℃以下に冷却し攪拌を停止する。次に遠心分離機を用いて、遠心沈降法により液中にて分級を行い、目開き４５μｍの篩いで濾過し、この濾液を会合液▲１▼とする。ついで、ヌッチェを用いて、会合液▲１▼よりウェットケーキ状の非球形状粒子を濾取した。その後、イオン交換水により洗浄した。
【０１８８】
この非球形状粒子をフラッシュジェットドライヤーを用いて吸気温度６０℃にて乾燥させ、ついで流動層乾燥機を用いて６０℃の温度で乾燥させた。前記塩析／融着段階および形状制御工程のモニタリングにおいて、攪拌回転数、および加熱時間を制御することにより、形状および形状係数の変動係数を制御し、さらに液中分級により、粒径および粒度分布の変動係数を調整して、表１に示す着色粒子１、及び２を得た。
【０１８９】
着色粒子３の作製（懸濁重合法の例）
スチレン＝１６５ｇ、ｎ−ブチルアクリレート＝３５ｇ、カーボンブラック＝１０ｇ、ジ−ｔ−ブチルサリチル酸金属化合物＝２ｇ、スチレン−メタクリル酸共重合体＝８ｇ、パラフィンワックス（ｍｐ＝７０℃）＝２０ｇを６０℃に加温し、ＴＫホモミキサー（特殊機化工業社製）にて１２０００ｒｐｍで均一に溶解、分散した、これに重合開始剤として２，２′−アゾビス（２，４−バレロニトリル）＝１０ｇを加えて溶解させ、重合性単量体組成物を調製した。ついで、イオン交換水７１０ｇに０．１Ｍ燐酸ナトリウム水溶液４５０ｇを加え、ＴＫホモミキサーにて１３０００ｒｐｍで攪拌しながら１．０Ｍ塩化カルシウム６８ｇを徐々に加え、燐酸三カルシウムを分散させた懸濁液を調製した。この懸濁液に上記重合性単量体組成物を添加し、ＴＫホモミキサーにて１００００ｒｐｍで２０分間攪拌し、重合性単量体組成物を造粒した。その後、攪拌翼の構成が図４に示したような構成の反応装置（交差角αは４５°）を使用し、７５〜９５℃にて５〜１５時間反応させた。塩酸により燐酸三カルシウムを溶解除去し、次に遠心分離機を用いて、遠心沈降法により液中にて分級を行い、ついで濾過、洗浄、乾燥させた。
【０１９０】
前記重合時にモニタリングを行い、液温度、攪拌回転数、および加熱時間を制御することにより、形状および形状係数の変動係数を制御し、さらに液中分級により、粒径および粒度分布の変動係数を調整して、下記表１に示す着色粒子３を得た。
【０１９１】
【表１】

【０１９２】
以上の着色粒子１〜３と下記表２、表３、表４に示す外添剤を添加し、ヘンシェルミキサーにて３０ｍ／ｓｅｃの回転条件で混合してトナー１〜９を作製した。
【０１９３】
【表２】

【０１９４】
【表３】

【０１９５】
＊酸化チタン１：オクチルトリメトキシシラン処理酸化チタン
（数平均一次粒子径＝１５ｎｍ）
＊酸化チタン２：ステアリン酸亜鉛処理酸化チタン
（数平均一次粒子径＝２０ｎｍ）
＊酸化チタン３：ステアリン酸亜鉛処理酸化チタン
（数平均一次粒子径＝４０ｎｍ）
【０１９６】
【表４】

【０１９７】
現像剤の作製
下記トナーとキャリアよりなる現像剤を作製した。
【０１９８】
また、前記これら「トナー１」〜「トナー９」のそれぞれとシリコーン樹脂を被覆した体積平均粒径が６０μｍのフェライトキャリアを混合してトナー濃度が６％の現像剤を作製し印字評価に使用した。この現像剤をトナーに対応して「現像剤１」〜「現像剤９」とする。
【０１９９】
クリーニングブレードとプラスチック部材の組み合わせの作製
クリーニング装置に用いるクリーニングブレードとプラスチック部材の組み合わせを表５のように１４種類作製した。クリーニングブレードとプラスチック部材は両面テープで接着した。
【０２００】
【表５】

【０２０１】
表中ＰＥＴ：ポリエチレンテレフタレートフィルム
ポリイミド：ポリイミドフィルムを示す。
【０２０２】
クリーニング条件
自由長９ｍｍのクリーニングブレードを感光体に回転方向に対してカウンター方向に線圧２０（Ｎ／ｍ）となるように重り荷重方式で当接した。
【０２０３】
評価
評価機としてコニカ社製デジタル複写機Ｋｏｎｉｃａ７０７５（コロナ帯電、レーザ露光、反転現像、静電転写、爪分離、クリーニングブレード、クリーニング補助ブラシローラー採用プロセスを有する）を用い、該複写機に表６に記載した感光体、現像剤、及びクリーニングブレードの組み合わせを搭載して評価した。クリーニング性及び画像評価は、画素率が７％の文字画像、人物顔写真、ベタ白画像、ベタ黒画像がそれぞれ１／４等分にあるオリジナル画像をＡ４中性紙にコピーした。環境条件は最も厳しいと思われる高温高湿環境（３０℃、８０％ＲＨ）にて連続１０万枚コピー行い、文字画像、ハーフトーン、ベタ白画像、ベタ黒画像を用いて評価した。評価項目及び評価基準を下記に示す。
【０２０４】
【表６】

【０２０５】
評価基準
画像ボケ（文字画像の解像度の低下により評価した）
○：１０万枚コピー終了まで画像ボケ発生なし
△：１０万枚コピー終了までに軽微な画像ボケが発生（文字の解読は可能）
×：１０万枚コピー終了までに顕著な画像ボケが発生（文字の解読が不可能）
クリーニング性（３万、５万及び１０万枚コピー終了後にＡ３紙に連続１０枚コピーを行い、ベタ白部でのクリーニング不良の発生の有無で判定）
○：１０万枚までトナーすり抜け等によるフィルミング発生なし
△：５万枚までトナーすり抜け等によるフィルミング発生なし
×：３万枚未満でトナーすり抜け等によるフィルミング発生
ブレードめくれ
○：１０万枚コピー中ブレードめくれ発生なし
×：１０万枚コピー中ブレードめくれ発生
総合画質（初期と１０万枚コピー後に評価した。）
○：初期及び１０万枚コピー後共に文字画像は鮮明に、ハーフトーン画像はなめらかに再現されて良好
△：初期は良好だが１０万枚コピー後の文字画像、又はハーフトーン画像に画像ボケやざらつきが若干見られる。
【０２０６】
×：１０万枚コピー後の文字画像、又はハーフトーン画像に画像ボケやざらつきが顕著。
【０２０７】
クリーニングブレードの振動の大きさ
振動の大きさ測定方法
クリーニングブレードが接合された支持部材に小野測器社製加速度検出器ＮＰ−３２１０のセンサーを取り付け、感光体が一定回転になったときの振動を前記センサーにより１０秒間読取り、該センサーからの出力データーを「ＯＮＯ ＳＯＫＫＩ ＣＦ６４００ ４チャンネルインテリジェントＦＦアナライザ」で演算処理して前記振動の振幅の平均値を得、これを前記ブレードの振動の大きさ（ｎｍ）で表した。
【０２０８】
感光体膜厚減耗量
感光体膜厚減耗量は実写評価開始時と１０万枚コピー終了時に測定した感光体の平均膜厚の差分を求め、膜厚減耗量とした。
【０２０９】
膜厚測定法
感光層の膜厚は均一膜厚部分をランダムに１０ケ所測定し、その平均値を感光層の膜厚とする。膜厚測定器は渦電流方式の膜厚測定器ＥＤＤＹ５６０Ｃ（ＨＥＬＭＵＴ ＦＩＳＣＨＥＲ ＧＭＢＴＥ ＣＯ社製）を用いて行った。
【０２１０】
その他評価条件
尚、上記デジタル複写機Ｋｏｎｉｃａ７０７５を用いたその他の評価条件は下記の条件に設定した。
【０２１１】
帯電条件
帯電器；スコロトロン帯電器、初期帯電電位を−７５０Ｖ
露光条件
露光部電位を−５０Ｖにする露光量に設定。
【０２１２】
現像条件
ＤＣバイアス；−５５０Ｖ
転写条件
転写極；コロナ帯電方式
評価結果を表７に示した。
【０２１３】
【表７】

【０２１４】
表７から明らかなように本発明の要件を満足した組み合わせＮｏ．１〜８、１０〜１４、及び１７〜１９は、画像ボケの発生もなく、クリーニング性も良好であり、膜厚減耗量も少ない。一方、本発明外のトナーを用いた組み合わせＮｏ．９は画像ボケが著しく発生しており、又、本発明外のクリーニングブレードとプラスチック部材の組み合わせのＮｏ．１５、２１及び２２はクリーニングブレードの振動が効果的に吸収されず、クリーニング性が低下したり、画像ボケが発生しており、組み合わせＮｏ．１６及び２０ではクリーニングブレードの振動が過大になり、ブレードめくれが発生している。
【０２１５】
【発明の効果】
前記実施例からも明らかなように、プラスチック部材を有するクリーニングブレードと現像剤を組み合わせた本発明を実施することにより、有機感光体上の残留トナーをブレードめくれや、トナーすり抜けの発生もなく、効果的に除去することができ、総合画質が良好な画像形成方法、画像形成装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の画像形成装置の全体の構成を示す概要構成図である。
【図２】本発明のクリーニングブレードを用いたクリーニング装置の構成図である。
【図３】（ａ）は、角のないトナー粒子の投影像を示す説明図であり、（ｂ）および（ｃ）は、それぞれ角のあるトナー粒子の投影像を示す説明図である。
【図４】重合トナー反応装置の一例を示す斜視図である。
【図５】重合トナー反応装置の一例を示す断面図である。
【図６】攪拌翼の形状の具体例を示す概略図である。
【符号の説明】
１２１ 感光体
１２２ 帯電器
１２３ 現像装置
１２４ 転写器
１２５ 分離器
１２６ クリーニング装置
１２６Ａ クリーニングブレード
１２６Ｂ プラスチック部材
１２７ ＰＣＬ（プレチャージランプ）
１３０ 露光光学系
１９１ 支持部材
ａ クリーニングブレードの自由長
ｂ プラスチック部材の自由長
ｔ₁ クリーニングブレードの厚さ
ｔ₂ プラスチック部材の厚さ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming method and an image forming apparatus used for an electrophotographic copying machine, a printer, and the like.
[0002]
[Prior art]
In recent years, an organic photoreceptor containing an organic photoconductive substance (hereinafter also simply referred to as a photoreceptor) has been most widely used as an image carrier used in an electrophotographic image forming apparatus. Organic photoconductors have advantages over other photoconductors, such as easy development of materials suitable for various exposure light sources from visible light to infrared light, the ability to select materials without environmental pollution, and low manufacturing costs. It is.
[0003]
However, the image forming method using an organic photoreceptor has various problems associated with the organic photoreceptor.
[0004]
(1) For example, as the number of times of image formation increases, cleaning defects become apparent, filming occurs due to deposition of paper dust or toner on an organic photoreceptor, and transfer performance is further reduced. Cause image unevenness.
[0005]
{Circle around (2)} When a cleaning blade is used as a cleaning device, contact friction between the organic photoreceptor and the cleaning blade is often unstable, and blade deterioration such as blade turning and blade squealing is likely to occur.
[0006]
On the other hand, in the electrophotographic image forming method, digital image forming has become mainstream due to the recent progress of digital technology. The digital image forming method is based on visualizing small dot images of one pixel such as 400 dpi (number of dots per inch), and high image quality technology that faithfully reproduces these small dot images is required. Has been.
[0007]
One such high image quality technology is a technology related to toner manufacturing technology. That is, an electrophotographic developer using a polymerized toner or an image forming method has been proposed as means for achieving uniform particle size distribution and shape of toner particles. Since the polymerized toner is produced by uniformly dispersing the raw material monomer in an aqueous system to produce a toner, a toner having a uniform toner particle size distribution and shape can be obtained. When development using these toners is used, an original image is obtained. Is easy to faithfully reproduce.
[0008]
However, new technical problems have arisen when the polymerized toner is employed in an image forming apparatus using an organic photoreceptor. That is, as described above, the polymerized toner is formed in a substantially spherical shape because the toner shape is formed by the polymerization process of the monomer. As already well known, spherical residual toner is liable to cause poor cleaning and subsequent filming. This causes deterioration in transfer performance and image unevenness.
[0009]
In order to prevent the above-mentioned filming of the organic photoreceptor, it is known to add a fluidizing agent such as hydrophobic silica to the toner. However, since these fluidizing agents have a small primary particle size, they are easily embedded in the toner surface, and the effects do not last long.
[0010]
On the other hand, in order to prevent filming, if an external additive having a large abrasive particle size is added, the surface wear of the organic photoconductor is increased due to friction with the cleaning blade, etc. There was a problem that the durability of the resin was reduced. Therefore, there has been a demand for technical development for solving these problems, a stable cleaning method and a method for using an external additive, in which the surface of the organophotoreceptor is small and scratches are not easily generated.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems, and even when an organic photoreceptor is used, an image forming method and an image forming method that can maintain a good cleaning performance for a long period of time and can form a good electrophotographic image without image defects. A forming apparatus is provided.
[0012]
[Means for Solving the Problems]
As a result of repeated studies to solve the above problems, the present inventors have effectively controlled the abrasiveness of the toner and the external additive using a fine particle external additive in which inorganic fine particles are fixed on the surface of the resin particle. It has been found that the filming can be effectively removed by using a cleaning method that does not substantially damage the surface of the organic photoreceptor.
[0013]
That is, the object of the present invention is achieved by taking any one of the following configurations.
1. The electrostatic latent image formed on the organic photoreceptor is developed with a developer containing toner, and the toner image visualized by the development is transferred from the organic photoreceptor to a transfer material. In the image forming method in which the toner remaining on the surface is removed using a urethane rubber cleaning blade having a JISA hardness of 55 to 90 at 25 ± 5 ° C., the cleaning blade has a rebound resilience of 25 to 80, and its tip is organic. The cleaning blade is pressed in the opposite direction (counter direction) to the rotation direction of the photosensitive member, and the cleaning blade has a thickness of 0.0 on the surface opposite to the pressed surface. 4 ~ 2mm polyethylene terephthalate or polyimide plastic member Adhesion The free length a of the cleaning blade and the free length b of the plastic member satisfy the relationship of Equation 1, and the thickness t of the cleaning blade ₁ And thickness t of plastic parts ₂ Is an image forming method characterized by satisfying the relationship of Formula 2 and the toner used in the developer is a toner obtained by adding fine particles in which inorganic fine particles are fixed to at least the surface of resin particles to colored particles.
[0014]
Formula 1
0.1 <b / a ≦ 0.9 (where a is 6 to 15 mm)
Formula 2
1 / 50 ≦ t ₂ / T ₁ ≦ 1 (however, t ₁ Is 0.5-10mm)
[0015]
2 . The number average particle diameter of fine particles obtained by fixing inorganic fine particles on the surface of the resin particles is 100 nm to 2000 nm. 1 The image forming method described.
[0016]
3 . The fine particles are added in an amount of 0.1 to 3.0% by mass in the toner. Or 2 The image forming method described.
[0017]
4 . The toner further comprises a fluidizing agent having a number average primary particle size of 5 to 49 nm added to the toner in an amount of 0.1 to 3.0% by mass. 3 The image forming method according to any one of the above.
[0018]
5 . 1 to 4 An image forming apparatus using the image forming method according to claim 1.
[0019]
The present invention will be described in more detail.
FIG. 1 is a schematic configuration diagram showing the overall configuration of the image forming apparatus of the present invention.
[0020]
The image forming apparatus shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B (not shown), an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. It is configured.
[0021]
The upper part of the image reading unit A is provided with automatic document feeding means for automatically conveying the document. The document placed on the document placing table 111 is separated and conveyed by the document conveying roller 112 to the reading position 113a. The image is read. The document after the document reading is completed is discharged onto the document discharge tray 114 by the document transport roller 112.
[0022]
On the other hand, the image of the original when placed on the platen glass 113 is read at a speed v of the first mirror unit 115 including the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by moving the second mirror unit 116 composed of the two mirrors and the third mirror in the same direction at the speed v / 2.
[0023]
The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 117. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.
[0024]
In the image forming unit C, as an image forming unit, a drum-shaped photosensitive member (hereinafter also referred to as a photosensitive drum) 121 that is an image carrier, a charger 122 that is a charging unit, and a developing unit that is a developing unit are provided on the outer periphery thereof. A device 123, a transfer device 124 as transfer means, a separator 125 as separation means, a cleaning device 126 and a PCL (precharge lamp) 127 are arranged in the order of operation. The photoconductor 121 is formed by coating a photoconductive compound on a drum base. For example, an organic photoconductor (OPC) is preferably used, and is driven to rotate in the clockwise direction shown in the drawing.
[0025]
After the rotating photosensitive member 121 is uniformly charged by the charger 122, the exposure optical system 130 performs image exposure based on the image signal called from the memory of the image processing unit B. The exposure optical system 130 as writing means uses a laser diode (not shown) as a light source, passes through a rotating polygon mirror 131, an fθ lens (no symbol), and a cylindrical lens (no symbol), and the optical path is bent by a reflection mirror 132 to perform main scanning. Thus, image exposure is performed on the photoconductor 121 at the position Ao, and a latent image is formed by rotation (sub-scanning) of the photoconductor 121. In one example of the present embodiment, the character portion is exposed to form a latent image.
[0026]
The latent image on the photoconductor 121 is reversely developed by the developing device 123, and a visible toner image is formed on the surface of the photoconductor 121. In the transfer paper transport section D, paper feed units 141 (A), 141 (B), and 141 (C) are provided below the image forming unit as transfer paper storage means for storing transfer paper P of different sizes. Further, a manual paper feed unit 142 that performs manual paper feed is provided on the side, and the transfer paper P selected from any of these is fed along the transport path 140 by the guide roller 143 and fed. The transfer paper P is temporarily stopped by a pair of registration rollers 144 that corrects the inclination and bias of the transfer paper to be transferred, and then is re-feeded. The toner image on the photoconductor 121 is transferred to the transfer paper P by the transfer device 124 at the transfer position Bo, and then the charge is removed by the separator 125. Separated, it is conveyed to the fixing device 150 by a conveying device 145.
[0027]
The fixing device 150 has a fixing roller 151 and a pressure roller 152. By passing the transfer paper P between the fixing roller 151 and the pressure roller 152, the toner is fused by heating and pressing. . After the toner image has been fixed, the transfer paper P is discharged onto a paper discharge tray 164.
[0028]
FIG. 2 is a configuration diagram of a cleaning device using the cleaning blade of the present invention.
[0029]
In the cleaning device, a cleaning blade 126A and a plastic member 126B are attached to a support member (generally a metal plate is used) 191. As the material of the cleaning blade, a rubber elastic body is used, and as the material, urethane rubber, silicon rubber, fluorine rubber, chloroprene rubber, butadiene rubber, etc. are known. Of these, urethane rubber is used as another rubber. It is particularly preferable in that it has superior wear characteristics. For example, urethane rubber obtained by reacting and curing polycaprolactone ester and polyisocyanate described in JP-A-59-30574 is preferable.
[0030]
The plastic member of the present invention means a member having a cleaning blade shape produced using a polymer material that can be plasticized to an arbitrary shape by heating. As the polymer material, both a thermoplastic resin and a thermosetting resin can be used. As the plastic member of the present invention, a commercially available plastic sheet cut into a blade shape can be used. Alternatively, a plastic sheet having a specific physical property value may be ordered from the manufacturer and manufactured using these plastic sheets.
[0031]
Polymer materials used for plastic members include polyethylene terephthalate, polystyrene, polyacrylate, polyethylene, polypropylene, polyarylate, styrene acrylate copolymer and other thermoplastic resins, glass fiber reinforced plastic, carbon fiber reinforced plastic and other reinforced plastics, Alternatively, a thermosetting polymer material having a small rubber elasticity cured by three-dimensional crosslinking is preferably used.
[0032]
In the present invention, when the plastic member 126B and the cleaning blade 126A are fixed to the support member 191, the plastic member is disposed so that the cleaning blade is in close contact with the photosensitive member on the surface opposite to the contact surface, and is attached to the support member. Hold. At this time, the portion where the cleaning blade is in contact with the plastic member has a mechanism that can reliably propagate and absorb the vibration generated by the blade to the plastic member. By adopting such a holding method, the vibration of the cleaning blade can be effectively absorbed by the plastic member, and the vibration of the blade can be stabilized.
[0033]
The proper pressure contact condition of the cleaning blade to the surface of the photoreceptor is determined by a delicate balance of various characteristics and is quite narrow. The setting varies depending on characteristics such as the thickness of the cleaning blade, and requires precision. However, the thickness of the cleaning blade is inevitably varied at the time of manufacture, so it cannot always be set under appropriate conditions. It may be out of the proper area. In particular, when combined with an organic photosensitive layer using a high molecular weight binder resin, it may cause blade turning or toner slipping if it is out of the proper area.
[0034]
Therefore, the present invention is also an effective means for canceling the variation in the characteristics of the cleaning blade. Even if there is a variation in the thickness of the cleaning blade, the vibration of the blade is effectively absorbed by the plastic member. The setting condition of the cleaning blade on the photosensitive member surface can be stably maintained in the appropriate region.
[0035]
In the present invention, it is preferable that the tip of the cleaning blade that is in pressure contact with the surface of the photoconductor is in pressure contact with a load applied in a direction opposite to the rotation direction of the photoconductor (counter direction). As shown in FIG. 2, it is preferable to form a pressure contact surface when the tip of the cleaning blade is pressed against the photosensitive member.
[0036]
The positional relationship between the cleaning blade and the plastic member of the present invention is such that a step is provided between the tips of both as shown in FIG. Furthermore, the free length of the plastic member is shorter than the free length of the cleaning blade. With this configuration, the cleaning blade vibration is absorbed by the plastic member without hindering deformation at the tip of the cleaning blade (deformation caused by pressure contact with the photosensitive member), and the cleaning blade vibration is absorbed. It can be stabilized.
[0037]
The cleaning device of the present invention is configured so that the ratio of the free length of the cleaning blade to the plastic member satisfies the formula 1 when the free length of the cleaning blade is a and the free length of the plastic member is b as shown in FIG. ing. The free length is the length of the portion where the cleaning blade and the plastic member are not held by the support member 191. As shown in FIG. 2, the cleaning blade and the plastic member before deformation from the end B of the support member 191 are shown. The length to each tip point is shown.
[0038]
Formula 1
0.1 <b / a ≦ 0.9
Deformation at the tip of the cleaning blade (deformation caused by pressure contact with the photosensitive member) by configuring so that b / a is in the above range, that is, b / a exceeds 0.1 and is 0.9 or less. It has been found that the cleaning blade can absorb the vibration of the cleaning blade with a plastic member without hindering the toner, and can realize a stable cleaning property without causing blade turning or toner slippage. Furthermore, in the present invention, the range of 0.3 to 0.7 is more preferable. On the other hand, if b / a is 0.1 or less, toner slip occurs easily, and if b / a is greater than 0.9, blade turning tends to occur.
[0039]
In the cleaning apparatus of the present invention, the thickness ratio of the cleaning blade to the plastic member is set to the thickness of the cleaning blade t as shown in FIG. ₁ , The thickness of the plastic member is t ₂ Then, it is preferable to be configured to satisfy the following formula.
[0040]
1/50 ≦ t ₂ / T ₁ ≦ 1
t ₂ / T ₁ Within the above range, i.e. t ₂ / T ₁ The cleaning blade is stably held on the support member, and the vibration of the cleaning blade is absorbed by the plastic member so that the blade is not turned over or slipped out of the toner. We found that it was possible to achieve the cleanability. Furthermore, t ₂ / T ₁ The value of is preferably in the range of 1/50 to 1/4. On the other hand, t ₂ / T ₁ Is less than 1/50, toner passes easily. ₂ / T ₁ If is larger than 1, blade turning is likely to occur.
[0041]
In the present invention, preferable values of the contact load P and the contact angle θ of the cleaning blade to the photosensitive member are P = 5 to 40 N / m and θ = 5 to 35 °.
[0042]
The contact load P is a normal vector value of the pressure contact force P ′ when the blade 126A is brought into contact with the photosensitive drum 121.
[0043]
The contact angle θ represents an angle formed between the tangent line X at the contact point A of the photosensitive member and the blade before deformation (shown by a dotted line in the drawing). Reference numeral 172 denotes a fixing screw for fixing the support member, and 193 denotes a load spring.
[0044]
The cleaning blade free length a represents the length of the tip point of the blade before deformation from the position of the end B of the support member 191 as shown in FIG. A preferable value of the free length is a = 6 to 15 mm. The thickness of the cleaning blade is preferably 0.5 to 10 mm. Here, the thickness of the cleaning blade and the plastic member of the present invention indicates a direction perpendicular to the bonding surface of the support member 191 as shown in FIG.
[0045]
The cleaning blade used in the present invention is preferably a rubber elastic body. By simultaneously controlling the physical properties of the cleaning blade and the plastic member, the cleaning conditions of the present invention can be adjusted better, and the toner cleaning performance can be controlled more effectively.
[0046]
Further, as another physical property of the cleaning blade, the hardness is preferably in the range of 55-90 JIS hardness at 25 ± 5 ° C. When it is smaller than 55, the cleaning performance tends to be lowered, and when it is larger than 90, the blade is easily reversed. The rebound resilience of the cleaning blade is preferably in the range of 25-80. When the impact resilience exceeds 80, the blade is easily reversed, and when it is less than 25, the cleaning performance is deteriorated. Young's modulus is 294-588 N / cm ² The thing of the range of is preferable.
[0047]
If necessary, the cleaning blade may be sprayed with a fluorine-based lubricant on the edge of the cleaning blade that is in contact with the photosensitive member, or further, a fluorine-based lubricant may be applied to the tip over the entire width direction. It is preferable to apply a dispersion in which a polymer and fluorine resin powder are dispersed in a fluorine solvent.
[0048]
Next, the organic photoreceptor of the present invention will be described.
In the present invention, an organic electrophotographic photoreceptor (organic photoreceptor) is an electrophotographic structure in which an organic compound has at least one of a charge generation function and a charge transport function essential to the construction of an electrophotographic photoreceptor. It means a photoreceptor, and all known organic electrophotographic photoreceptors such as a photoreceptor composed of a known organic charge generating material or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generating function and a charge transport function, etc. contains.
[0049]
The constitution of the organic photoreceptor used in the present invention is described below.
Conductive support
As the conductive support used in the photoreceptor of the present invention, either a sheet or a cylindrical support may be used, but a cylindrical conductive support is preferable in order to make the image forming apparatus compact.
[0050]
The cylindrical conductive support of the present invention means a cylindrical support necessary for forming an endless image by rotating, and the straightness is in the range of 0.1 mm or less and the deflection is 0.1 mm or less. A conductive support is preferred. Exceeding the roundness and shake range makes it difficult to form a good image.
[0051]
As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. As a conductive support, the specific resistance is 10 at room temperature. ^Three Ωcm or less is preferable.
[0052]
As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.
[0053]
Middle class
In the present invention, an intermediate layer having a barrier function may be provided between the conductive support and the photosensitive layer.
[0054]
In the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer, or to prevent charge injection from the support, an intermediate layer (including an undercoat layer) is provided between the support and the photosensitive layer. Including) can also be provided. Examples of the material for the intermediate layer include polyamide resins, vinyl chloride resins, vinyl acetate resins, and copolymer resins containing two or more of these resin repeating units. Of these subbing resins, a polyamide resin is preferable as a resin capable of reducing the increase in residual potential due to repeated use. The film thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.
[0055]
The intermediate layer most preferably used in the present invention includes an intermediate layer using a curable metal resin obtained by thermally curing an organometallic compound such as a silane coupling agent or a titanium coupling agent. As for the film thickness of the intermediate | middle layer using curable metal resin, 0.1-2 micrometers is preferable.
[0056]
Photosensitive layer
The photosensitive layer configuration of the photoreceptor of the present invention may be a single layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer. It is preferable that the generation layer (CGL) and the charge transport layer (CTL) be separated. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor. The most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.
[0057]
The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.
Charge generation layer
The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.
[0058]
A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, the CGM that can minimize the increase in residual potential due to repeated use has a three-dimensional and potential structure that can form a stable aggregate structure among a plurality of molecules. Specifically, a phthalocyanine having a specific crystal structure. CGM of pigments and perylene pigments. For example, CGMs such as titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays and benzimidazole perylene having a maximum peak at 2θ of 12.4 have little deterioration due to repeated use. Potential increase can be reduced.
[0059]
When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 μm to 2 μm.
[0060]
Charge transport layer
The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. Other substances may contain additives such as antioxidants as necessary.
[0061]
A known charge transport material (CTM) can be used as the charge transport material (CTM). For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM capable of minimizing the increase in residual potential due to repeated use has a high mobility and an ionization potential difference from the combined CGM of 0.5 (eV) or less, preferably 0 .25 (eV) or less.
[0062]
The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).
[0063]
Examples of the resin used for the charge transport layer (CTL) include polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate. Resin, silicone resin, melamine resin, and copolymer resin containing two or more of repeating units of these resins. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used.
[0064]
Most preferred as a binder for these CTLs is a polycarbonate resin. The polycarbonate resin is most preferable in improving the dispersibility and electrophotographic characteristics of CTM. The ratio of the binder resin to the charge transport material is preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. The thickness of the charge transport layer is preferably 10 to 40 μm.
[0065]
Examples of the solvent or dispersion medium used for layer formation of the intermediate layer and photosensitive layer of the present invention include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, and methyl ethyl ketone. , Methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane , Tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. And the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.
[0066]
Next, as a coating processing method for producing the organic electrophotographic photoreceptor of the present invention, a coating processing method such as dip coating, spray coating, circular amount regulation type coating or the like is used. In order to prevent the lower layer film from being dissolved as much as possible, it is preferable to use a coating method such as spray coating or circular amount regulation type (circular slide hopper type is a typical example) coating in order to achieve uniform coating processing. It is most preferable that the protective layer of the present invention uses the circular amount regulation type coating method. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.
[0067]
In the present invention, image blurring, streak-like, or spot-like image defects in a high-temperature and high-humidity environment that occurs when an organic photoreceptor is used, use a cleaning blade to which the plastic member is bonded and a resin in the toner. It has been found that it is effective to add a fine particle external additive having inorganic fine particles fixed to the surface of the particle, and to carry the external additive on the surface of a cleaning member (cleaning blade or the like) during cleaning. That is, by externally adding fine particles (hereinafter also referred to as composite particles) in which inorganic fine particles are fixed to the surface of resin particles to the toner, the adsorbed component on the surface of the photoreceptor can be effectively removed, and image flow, streaks, or spots The inventors have found that the problem of occurrence of image defects can be solved, and have completed the present invention.
[0068]
Hereinafter, the toner used in the present invention will be described.
The toner of the present invention is a toner obtained by adding fine particles (composite particles) in which inorganic fine particles are fixed at least on the surface of resin particles to colored particles.
[0069]
Since the surface of the composite particle has the inorganic fine particles fixed thereto, it has a high charge imparting ability due to its effect. Further, due to the inorganic fine particles on the surface, there is also a polishing force of the photoreceptor, and the cleaning property is high. In addition, since resin particles are used as the core, it has a flexible structure, can relieve stress on the photoreceptor and toner during cleaning, etc. Since burying can be suppressed, a stable image can be formed over a long period of time.
[0070]
Examples of the resin particles of the composite particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.
[0071]
The composition of the resin particles is not particularly limited. In general, vinyl-based organic fine particles are preferable. This is because it can be easily produced by a production method such as an emulsion polymerization method or a suspension polymerization method. Specifically, such as styrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pt-butylstyrene, etc. Styrene or styrene derivatives, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, methacrylic acid ester derivatives such as 2-ethylhexyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid n-butyl, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, acrylic acid ester derivatives such as 2-ethylhexyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, bromide Bini , Vinyl halides such as vinyl fluoride and vinylidene fluoride, vinyl esters such as vinyl propionate and vinyl acetate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone Vinyl ketones such as N-vinyl carbazole, N-vinyl indole, N-vinyl compounds such as N-vinyl pyrrolidone, vinyl compounds such as vinyl naphthalene and vinyl pyridine, acrylonitrile, methacrylonitrile, acrylamide, N-butyl acrylamide, There are acrylic acid or methacrylic acid derivatives such as N, N-dibutylacrylamide, methacrylamide, N-butylmethacrylamide, and N-octadecylacrylamide. These vinyl monomers can be used alone or in combination.
[0072]
The resin particles can be produced by an emulsion polymerization method or a suspension polymerization method. The emulsion polymerization method is a method in which the above monomer is added and emulsified in water containing a surfactant, followed by polymerization. As the surfactant, sodium dodecylbenzenesulfonate, polyvinyl alcohol, ethylene oxide adduct, Any substance used as a surfactant such as sodium alcohol sulfate can be used without any particular limitation. Furthermore, the use of reactive emulsifiers, polymerization with hydrophilic monomers such as persulfate-based initiators such as vinyl acetate and methyl acrylate, methods of copolymerizing water-soluble monomers, So-called non-emulsification polymerization methods such as a method using an oligomer, a method using a decomposable emulsifier, and a method using a cross-linked emulsifier are also suitable. Examples of reactive emulsifiers include sulfonates of acrylic amides and salts of maleic acid derivatives. The non-emulsification polymerization method is not affected by the residual emulsifier and is suitable when the organic fine particles are used alone.
[0073]
Polymerization initiators required for synthesizing resin particles include peroxides such as benzoyl peroxide and lauryl peroxide, and azo polymerization initiators such as azobisisobutyronitrile and azobisisovaleronitrile. It is done. These addition amounts are preferably 0.1 to 2% by mass with respect to the monomer. If it is less than this amount, the polymerization reaction will be insufficient, causing the problem of the monomer itself remaining. Further, if the amount is excessive, a decomposition product of the polymerization initiator remains, which affects the chargeability. Further, since the polymerization reaction is too early, the molecular weight is reduced. Furthermore, in the emulsion polymerization method and the like, potassium persulfate, sodium thiosulfate and the like can be used as a polymerization initiator.
[0074]
The composite particles are produced by adding and mixing inorganic fine particles to the resin particles. Next, an ordered mixture is formed and inorganic fine particles are electrostatically attached to the surface of the resin particles, and then mechanical energy is applied to fix the inorganic fine particles to the surface of the resin particles. Here, the term “adhesion” refers to a state in which the adhesion rate described in JP-A-4-291352 is 25% or more.
[0075]
That is, the fixation rate defines the state of fixing of the inorganic fine particles, and defines the embedded state of the inorganic fine particles with respect to the core resin particles. This sticking rate is specifically calculated by the following formula.
[0076]
When the specific surface area of the resin particles is Sa, the specific surface area of the inorganic fine particles is Sb, the specific surface area of the composite particles after fixing the inorganic fine particles on the surface of the resin particles is Sh, and the addition rate of the inorganic fine particles to the resin particles is x,
[0077]
[Expression 1]

[0078]
It is shown.
This fixing rate is preferably 25% or more and less than 100%. In particular, 40 to 80% is preferable. If the fixation rate is less than 25%, the degree of fixation of the inorganic fine particles to the resin particles becomes low, and liberation of the inorganic fine particles present on the surface occurs. For this reason, if the use is repeated for a long period of time, a problem of scratches on the photoreceptor occurs due to the liberation of the inorganic fine particles. The adjustment of the fixing rate can be performed by variously controlling the conditions in the manufacturing apparatus for fixing.
[0079]
In addition, when forming an ordered mixture, in this invention, it is good to produce at the atmospheric temperature below the glass transition temperature Tg of resin which comprises the surface of a resin particle. That is, when the ordered mixture is formed at a temperature of Tg or higher, coalescence of the resin particles occurs.
[0080]
The ratio between the inorganic fine particles constituting the composite particles and the resin particles serving as nuclei depends on the respective particle diameters, and the inorganic fine particles may be added so as to uniformly cover the resin particles serving as the nuclei. Generally, the inorganic fine particles are preferably 5 to 30% by mass with respect to the resin particles.
[0081]
In order to form an ordered mixture, any apparatus capable of uniformly and electrostatically adhering inorganic fine particles to the core resin particle surface can be used. For example, a Henschel mixer, an OM dither, a turbuler mixer, a Roedige mixer, a V-type mixer, and the like can be given.
[0082]
As a mechanical energy imparting device for fixing inorganic particles adhering electrostatically to the surface, “Hybridizer” (manufactured by Nara Machinery Co., Ltd.) and “Free Mill” (manufactured by Nara Machinery Co., Ltd.), modified impact-type crushers. "Angmill" (manufactured by Hosokawa Micron Corporation), "Kryptron" (manufactured by Kawasaki Heavy Industries, Ltd.) and the like can be used. When the inorganic fine particles are fixed to the surface of the resin particles using this apparatus, not only simple mechanical energy but also heating or cooling from the outside is possible. That is, when a mechanical impact force is applied in a device that rotates at a high speed, heat is generated by the energy of the collision, and the internal temperature rises. When the inside of the apparatus reaches a temperature higher than the Tg of the resin particles, there is a problem that fusion occurs with the inside of the resin particles and aggregated particles are generated. This requires cooling and control. On the other hand, when the internal temperature is lower than Tg by 30 ° C. or more, excessive energy is required for fixing, the collision energy increases, and problems such as pulverization of resin particles occur. In order to solve this problem, it is necessary to raise the temperature to about Tg. In this case, it is necessary to heat from the outside.
[0083]
As a method for controlling the temperature from the outside, a method in which a heated medium is circulated through a jacket installed outside and controlled is preferable. The internal temperature is measured by the temperature of the circulating air measured by a thermometer installed at a site for fixing the resin particles and the inorganic fine particles. As a medium for circulation, there is water or oil.
[0084]
The charge amount of the composite particles is preferably 1 to 40 μC / g in absolute value. This charge amount can be controlled by controlling the chargeability of the inorganic fine particles adhering to the surface and by controlling the chargeability of the resin particles serving as the nucleus.
[0085]
The number average particle size of the composite particles is preferably in the range of 100 to 2000 nm, and more preferably in the range of 200 to 1200 nm. If the thickness is less than 100 nm, the buffering effect of the cleaning blade on the toner and the photoreceptor is small, and the effect of preventing filming and the like is small. On the other hand, if it is larger than 2000 nm, there is a problem that the composite particles are separated from the toner, and the scattered particles cause contamination of the band electrode and the transfer electrode, thereby causing image defects such as white stripes. The addition amount of the composite particles is preferably 0.1 to 5.0% by mass in the toner (here, the total mass of the toner indicates the total mass including the composite particles and fine particles described later). Especially preferably, it is 0.2-3.0 mass%, Most preferably, it is 0.4-1.5 mass%.
[0086]
An example of producing composite particles is shown below.
Titanium oxide 1 having a number average primary particle size of 0.3 μm (methyl methacrylate: 9: 1 styrene) and hydrophobized with octyltrimethoxysilane as inorganic fine particles 1 (number average) Primary particle size = 15 nm) was used. 17 parts by mass of inorganic fine particles are added to 100 parts by mass of the resin particles, put into an OM dizer (manufactured by Nara Machinery Co., Ltd.), and circulating water at 30 ° C. as a medium from the outside of the apparatus in which the inorganic fine particles and the resin particles are mixed. The mixture was mixed at 500 rpm for 3 minutes. The product temperature during mixing was 30 ° C. When the obtained ordered mixture was observed with a scanning electron microscope, it was found that inorganic fine particles were uniformly and electrostatically adhered to the surface of the resin particles.
[0087]
Next, this ordered mixture is put into a hybridizer (manufactured by Nara Machinery Co., Ltd.) and heated while circulating with circulating water at 45 ° C. as a medium from the outside of the apparatus where mechanical impact force is repeatedly applied to the inorganic fine particles and resin particles. The composite particles of the present invention were obtained by treating for 3 minutes under conditions of a speed of 100 m / sec. The internal temperature (product temperature) was 56 ° C. Furthermore, the state of adhesion inside the machine was observed, and it was good without any particular adhesion. Further, it was confirmed by observation with a scanning electron microscope that there was no coalescence of resin particles.
[0088]
Further, it is preferable to use a fluidizing agent of fine particles of 5 to 49 nm in combination with the composite particles. Examples of such fluidizers that are preferably used include silica, alumina, titania, zirconia, and the like.
[0089]
The amount of the fluidizing agent added is 0.1 to 3.0% by mass, preferably 0.3 to 2.5% by mass in the toner. If added beyond this range, there is a problem that the fine particles themselves are liberated, and the scattered particles cause contamination of the band electrode and the transfer electrode, leading to image defects such as white stripes. Furthermore, since the fine particles are present in the toner in a free state, it causes damage to the photosensitive member, and damages the photosensitive member to induce so-called black spots and white spots. On the other hand, if it is too small, the fluidity of the toner becomes insufficient and it is difficult to form a good image.
[0090]
The above particle diameter is a number average primary particle diameter, which is magnified 2000 times by observation with a transmission electron microscope, observed 100 particles, and measured by image analysis.
[0091]
In addition, it is preferable that the inorganic fine particles and the fluidizing agent of the composite particles have been subjected to a hydrophobic treatment. In the case of performing the hydrophobizing treatment, it is preferable to hydrophobize with a so-called coupling agent such as various titanium coupling agents and silane coupling agents, or silicone oil, and further, aluminum stearate, zinc stearate, calcium stearate. Hydrophobic treatment with a higher fatty acid metal salt such as is also preferably used.
[0092]
In addition to the fine particle external additive, a lubricant may be added to the toner of the present invention. For example, zinc stearate, aluminum, copper, magnesium, calcium salt, zinc oleate, manganese, iron, copper, magnesium salt, zinc palmitate, copper, magnesium, calcium salt, linoleic acid Examples thereof include metal salts of higher fatty acids such as zinc and calcium salts, and zinc and calcium ricinoleic acid salts. The addition amount of these lubricants is preferably about 0.1 to 5% by mass with respect to the toner.
[Tonerization process]
As a method for adding the external additive, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.
[0093]
In addition to the colorant and the release agent, the toner may be added with a material that can provide various functions as a toner material. Specific examples include charge control agents. These components can be added in the production stage of the colored particles at the stage of the toner (also referred to as colored particles) before adding the external additive. The colored particles may be prepared by a conventional pulverization method or a polymerization method.
[0094]
When producing colored particles by a pulverization method, a release agent and a charge control agent can be added at the kneading stage of the resin and the pigment. On the other hand, in the case of producing by a polymerization method, a method of adding at the stage of resin polymerization, a method of adding simultaneously with a pigment or the like at the stage of resin particle aggregation after the production of resin particles, and the like can be mentioned.
[0095]
In addition, as a mold release agent in the polymerization method, it is preferable to use various known ones that can be dispersed in water. Specific examples include olefinic waxes such as polypropylene and polyethylene, modified products thereof, natural waxes such as carnauba wax and rice wax, and amide waxes such as fatty acid bisamides. It has already been mentioned that these are added as release agent particles and are preferably salted out / fused together with resin and colorant.
[0096]
Similarly, various known charge control agents in the polymerization method 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.
[0097]
These release agent and charge control agent particles preferably have a number average primary particle size of about 10 to 500 nm in a dispersed state.
[0098]
Hereinafter, the toner (colored particles) by the polymerization method preferably used in the present invention will be described.
[0099]
As the toner applied to the present invention, a polymerized toner having a relatively uniform particle size distribution and shape of individual toner particles is preferable. Here, the polymerized toner means a toner obtained by forming a binder resin for toner and forming the toner shape by polymerization of a raw material monomer of the binder resin and subsequent chemical treatment. More specifically, it means a toner obtained through a polymerization reaction such as suspension polymerization or emulsion polymerization and, if necessary, a fusing step between particles carried out after the polymerization reaction.
[0100]
The polymerized toner used in the present invention is preferably a toner having a specific shape. The polymerized toner that can be preferably used in the present invention will be described below.
[0101]
As a preferred polymerized toner applied to the present invention, a toner having 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6 and a coefficient of variation of the shape factor of 16% or less is used. It is to be. It has been found that when a polymerized toner having such characteristics is used, the vibration of the cleaning blade can be stabilized and excellent cleaning performance can be exhibited.
[0102]
Also, the vibration stability of the cleaning blade varies depending on the particle size of the toner particles. The smaller the particle size, the higher the adhesion force to the image carrier, so that the vibration is likely to be excessive and the toner is contained in the cleaning blade. There is a high probability of passing through. However, when the toner particle diameter is large, such slip-through is reduced, but there is a problem that image quality such as resolution is lowered.
[0103]
As a result of studying from the above viewpoint, the toner having a variation coefficient of the toner shape factor of 16% or less and a toner having a number variation coefficient of 27% or less in the number particle size distribution of the toner, It has been found that high-quality image quality can be formed over a long period of time with excellent fine line reproducibility.
[0104]
In addition, by using toner particles with no corners at 50% by number or more and controlling the number variation coefficient in the number particle size distribution to 27% or less, excellent cleaning properties and fine line reproducibility, and high quality image quality for a long time Can be formed over.
[0105]
The shape factor of the toner is expressed by the following formula and indicates the degree of roundness of the toner particles.
[0106]
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.
[0107]
This shape factor is obtained by taking a photograph in which toner particles are magnified 2000 times with a scanning electron microscope, and then analyzing a photographic image using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. Was measured. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.
[0108]
As the polymerized toner, the number of toner particles having a shape factor in the range of 1.2 to 1.6 is preferably 65% by number or more, and more preferably 70% by number or more.
[0109]
When 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 triboelectric chargeability on the developer conveying member and the like becomes more uniform, and excessively charged toner is accumulated. In addition, since it becomes easier to replace the toner from the surface of the developer conveying member, problems such as development ghost are less likely to occur. Further, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and the chargeability of the toner is stabilized.
[0110]
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. Thus, there is a method in which a toner having a shape factor of 1.2 to 1.6 is prepared and added to a normal toner so as to be within the range of the present invention. In addition, the overall shape is controlled at the stage of adjusting the so-called polymerization method toner, and the toner whose shape factor is adjusted to 1.0 to 1.6 or 1.2 to 1.6 is similarly added to the normal toner. There is a way to adjust.
[0111]
The variation coefficient of the shape factor of the polymerized 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. ]
The variation coefficient of the shape factor is preferably 16% or less, and more 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.
[0112]
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).
[0113]
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.
[0114]
Although it does not specifically limit as a monitoring method, The flow type particle image analyzer FPIA-2000 (made by Toa Medical Electronics Co., Ltd.) 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.
[0115]
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). In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikkaki Co., Ltd.) that outputs a 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.
[0116]
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). ]
The number variation coefficient of the toner is preferably 27% or less, and 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.
[0117]
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.
[0118]
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 an aqueous medium before polymerization. In other words, repeated mechanical shearing by a homomixer, homogenizer, etc. on large oil droplets of a polymerizable monomer reduces 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.
[0119]
The toner particles having no corners are toner particles that do not substantially have a protrusion that concentrates charges or a protrusion that easily wears due to stress. That is, as shown in FIG. When the major axis of the particle T is L, a circle C having a radius (L / 10) is rolled into the toner T when the inner side is rolled in contact with the peripheral line of the toner particle T at one point. The case where the toner particles do not substantially protrude outside is referred to as “toner particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less. The “major diameter of toner particles” refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on a plane is sandwiched between two parallel lines. FIGS. 3B and 3C show projection images of toner particles having corners.
[0120]
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.
[0121]
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.
[0122]
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.
[0123]
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 the conditions such as the number of revolutions of the stirring blade and the stirring time appropriate, 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.
[0124]
The toner of the present invention preferably has a number average particle diameter of 3 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.
[0125]
When the number average particle diameter is 3 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 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.
[0126]
As the polymerized toner preferably used in the present invention, when the particle diameter of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the particle size distribution of toner particles, the relative frequency of toner particles contained in the most frequent class (m ₁ ) And the relative frequency (m of toner particles contained in the next most frequent class after the most frequent class) ₂ ) And the toner (M) is preferably 70% or more.
[0127]
Relative frequency (m ₁ ) And relative frequency (m ₂ ) Is 70% or more, the dispersion of the particle size distribution of the toner particles is narrowed. Therefore, the use of the toner in the image forming process can reliably suppress the occurrence of selective development. .
[0128]
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.
[0129]
〔Measurement condition〕
(1) Aperture: 100 μm
(2) Sample preparation method: Electrolyte [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and a measurement sample 10-20 mg was added thereto. Add This system is prepared by dispersing for 1 minute with an ultrasonic disperser.
[0130]
Among the methods for controlling the shape factor, the polymerization toner is preferable because it is simple as a production method and has excellent surface uniformity as compared with the pulverized toner.
[0131]
The polymerized toner is produced by emulsion polymerization of monomers in a suspension polymerization method or a liquid obtained by adding an emulsion of necessary additives to produce fine polymer particles, and then an organic solvent, an aggregating agent, etc. It can manufacture by the method of adding and associating. 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.
[0132]
That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer. Various constituent materials are dissolved or dispersed in the polymerizable monomer. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction apparatus which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare a toner.
[0133]
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 also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of associating a plurality of fine particles composed of resin particles and a coloring material, or dispersed particles of resin particles and a coloring agent, in particular, after dispersing them in water using an emulsifier, the critical aggregation concentration The above flocculant is added for salting out, and at the same time, the formed polymer itself is heated and fused at a temperature equal to or higher than the glass transition temperature to gradually grow the particle size while forming fused particles. Then, a large amount of water is added to stop the particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated and dried in a fluidized state while containing water, whereby toner Can be formed. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the flocculant.
[0134]
In addition, the aqueous medium as used in the field of this invention shows what contained 50 mass% or more of water at least.
[0135]
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 or styrene derivatives such as pn-dodecylstyrene, 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 Isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc., acrylate derivatives, 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 compounds or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, and acrylamide. These vinyl monomers can be used alone or in combination.
[0136]
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.
[0137]
Furthermore, multifunctional 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.
[0138]
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.
[0139]
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.
[0140]
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.
[0141]
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.
[0142]
The flocculant used is not particularly limited, but those selected from metal salts are 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.
[0143]
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.
[0144]
The addition amount of the flocculant 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.
[0145]
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, t-butanol, methoxyethanol, and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. In particular, ethanol, propanol, and isopropanol are preferable.
[0146]
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.
[0147]
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 existing water slightly swells with respect to the polymer in which the polar group is present.
[0148]
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.
[0149]
As the colorant used in the toner, carbon black, magnetic material, dye, pigment and the like can be arbitrarily used. As the carbon black, channel black, furnace black, acetylene black, thermal black, lamp black and the like are 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.
[0150]
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.
[0151]
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.
[0152]
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.
[0153]
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.
[0154]
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.
[0155]
In a suspension polymerization method toner in which a toner component obtained by dispersing or dissolving a toner component such as a colorant in a so-called 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. That is, when a large amount of toner particles having a shape factor of 1.2 or more are formed, the flow of the medium in the reaction vessel is turbulent and the polymerization proceeds to exist in an aqueous medium in a suspended state. When the oil droplets gradually become polymerized, the oil droplets become soft particles. By colliding the particles, particle coalescence is promoted, and particles with an irregular shape are obtained. . When spherical toner particles having a shape factor smaller than 1.2 are formed, spherical particles can be obtained by using a laminar flow of the medium in the reaction vessel to avoid particle collision. By this method, the toner shape distribution can be controlled within the scope of the present invention. The polymerization toner reaction apparatus preferably used in the present invention will be described below.
[0156]
First, the reaction apparatus preferably used for the production of the polymerized toner will be described. 4 and 5 are a perspective view and a cross-sectional view, respectively, showing an example of the polymerized toner reaction device. In the reaction apparatus shown in FIGS. 4 and 5, a rotating shaft 3 is vertically suspended at the center of a vertical cylindrical stirring tank 2 in which a jacket 1 for heat exchange is mounted on the outer periphery, and stirring is performed on the rotating shaft 3. A lower stirrer blade 40 disposed close to the bottom surface of the tank 2 and a stirrer blade 50 disposed further upward are provided. The upper agitating blade 50 is disposed with a crossing angle α preceding the agitating blade 40 located in the lower stage in the rotational direction. In the production of the toner of the present invention, the crossing angle α is preferably less than 90 degrees (°). The lower limit of the intersection angle α is not particularly limited, but is preferably about 5 ° or more, and more preferably 10 ° or more. In the case where a three-stage stirring blade is provided, the crossing angle α is preferably less than 90 degrees between adjacent stirring blades.
[0157]
By setting it as such a structure, a medium is first stirred by the stirring blade 50 arrange | positioned in the upper stage, and the flow to the lower side is formed. Next, the flow formed by the upper stirring blade 50 is further accelerated downward by the stirring blade 40 disposed in the lower stage, and a downward flow is also separately formed in the stirring blade 50 itself, and the flow as a whole is increased. Presumed to be accelerated and proceed. As a result, a flow area having a large shear stress formed as a turbulent flow is formed, and it is estimated that the shape of the obtained toner particles can be controlled.
[0158]
4 and 5, arrows indicate the rotation direction, 7 is an upper material inlet, 8 is a lower material inlet, and 9 is a turbulent flow forming member for making stirring effective.
[0159]
Here, the shape of the stirring blade is not particularly limited, but it may be a rectangular plate, a notch in a part of the blade, one or more holes in the center, and a so-called slit. Can be used. Specific examples of these are shown in FIG. The stirring blade 5a shown in FIG. 6 (a) has no medium hole, the stirring blade 5b shown in FIG. 6 (b) has a large middle hole 6b in the center, and the stirring blade 5c shown in FIG. 6 (c). Has a horizontally elongated hole 6c (slit), and the stirring blade 5d shown in FIG. 4D has a vertically elongated hole 6d (slit). In addition, when a three-stage stirring blade is provided, the middle hole formed in the upper stirring blade and the middle hole formed in the lower stirring blade may be the same, even if they are different. There may be.
[0160]
The gap between the upper and lower stirring blades having the above-described configuration is not particularly limited, but it is preferable to have a gap at least between the stirring blades. Although the reason for this is not clear, it is considered that the stirring efficiency is improved because a medium flow is formed through the gap. However, the gap has a width of 0.5 to 50%, preferably 1 to 30%, with respect to the liquid surface height in the stationary state.
[0161]
Further, the size of the stirring blade is not particularly limited, but the total height of all the stirring blades is 50% to 100%, preferably 60% to 95% of the liquid surface height in the stationary state. is there.
[0162]
On the other hand, in a polymerization method toner that associates or fuses resin particles in an aqueous medium, by controlling the flow and temperature distribution of the medium in the reaction vessel at the fusing stage, and further in the shape control step after fusing. By controlling the heating temperature, the number of rotations of stirring, and the time, the shape distribution and shape of the entire toner can be arbitrarily changed.
[0163]
That is, in the polymerization method toner that associates or fuses the resin particles, the flow in the reaction apparatus is made into a laminar flow, and the agitation step and the agitation tank that can make the internal temperature distribution uniform are used. By controlling the temperature, the number of rotations, and the time in the shape control step, it is possible to form a toner having a desired shape factor and uniform shape distribution. The reason for this is that if the laminar flow is fused in a place where the laminar flow is formed, strong stress is not applied to the particles (aggregation or agglomerated particles) in which aggregation and fusion proceed, and in laminar flow where the flow is accelerated It is estimated that this is because the shape distribution of the fused particles becomes uniform as a result of the uniform temperature distribution in the stirring tank. Further, the fused particles gradually become spherical by heating and stirring in the subsequent shape control step, and the shape of the toner particles can be arbitrarily controlled.
[0164]
As the agitation tank used in the production of the polymerization method toner for associating or fusing the resin particles, those similar to the suspension polymerization method described above can be used. In this case, it is necessary not to provide an obstacle such as a baffle plate that forms a turbulent flow in the stirring tank.
[0165]
The shape of the stirring blade is not particularly limited as long as it forms a laminar flow and does not form a turbulent flow, but it is formed by a continuous surface such as the rectangular plate shown in FIG. Those are preferable, and may have a curved surface.
<Developer>
The toner used in the present invention may be a one-component developer or a two-component developer, but is preferably a two-component developer.
[0166]
When used as a one-component developer, there is a method in which the toner is used as it is as a non-magnetic one-component developer. Usually, however, the toner particles contain about 0.1 to 5 μm of magnetic particles as a magnetic one-component developer. Use. As a method for its inclusion, it is usually contained in non-spherical particles in the same manner as the colorant.
[0167]
Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead are used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 60 μm.
[0168]
The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.
[0169]
The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene / acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, a styrene acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like can be used. it can.
[0170]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the text, “part” means “part by mass”.
[0171]
The following photoreceptors were prepared as the photoreceptors used in the examples.
Production of photoreceptor 1
<Underlayer>
Titanium chelate compound (TC-750: manufactured by Matsumoto Pharmaceutical) 30g
Silane coupling agent (KBM-503: manufactured by Shin-Etsu Chemical Co., Ltd.) 17g
150 ml of 2-propanol
It apply | coated so that it might become a dry film thickness of 0.5 micrometer on the cylindrical electroconductive support body of (phi) 100mm using the said coating liquid.
[0172]
<Charge generation layer>
Y-type titanyl phthalocyanine (Maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 27.3 at 2θ) 60 g
700 g of silicone-modified butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co., Ltd.)
2-butanone 2000ml
Were mixed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the undercoat layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.2 μm.
[0173]
<Charge transport layer>
Charge transport material [N- (4-methylphenyl) -N- {4-
(Β-Phenylstyryl) phenyl} -p-toluidine] 225 g
Polycarbonate (viscosity average molecular weight 30,000) 300g
Antioxidant (Sanol LS2626: Sankyosha) 6g
Dichloromethane 2000ml
Were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 20 μm.
[0174]
Production of photoconductor 2
Photoreceptor 2 was produced in the same manner as Photoreceptor 1 except that the polycarbonate of the charge transport layer of Photoreceptor 1 was replaced with a polycarbonate having a viscosity average molecular weight of 80,000.
[0175]
A toner used in the present invention was prepared as follows.
Preparation of colored particles 1 and 2 (example of emulsion polymerization method)
Add 0.90 kg of sodium n-dodecyl sulfate and 10.0 l of pure water and dissolve with stirring. To this solution, 1.20 kg of Legal 330R (Cabot Black Carbon Black) was gradually added and stirred well for 1 hour, followed by continuous dispersion for 20 hours using a sand grinder (medium disperser). This is referred to as “colorant dispersion 1”. A solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 l of ion-exchanged water is referred to as “anionic surfactant solution A”.
[0176]
A solution composed of 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct and 4.0 l of ion-exchanged water is referred to as “nonionic surfactant solution B”. A solution obtained by dissolving 223.8 g of potassium persulfate in 12.0 l of ion-exchanged water is referred to as “initiator solution C”.
[0177]
Into a 100-liter GL (glass lining) reaction kettle equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device, a WAX emulsion (a polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration = 29.9%) ) Put 3.41 kg, the total amount of “anionic surfactant solution A” and the total amount of “nonionic surfactant solution B”, and start stirring. Then, 44.0 l of ion exchange water is added.
[0178]
Heating was started and when the liquid temperature reached 75 ° C., the entire amount of “Initiator Solution C” was added dropwise. Thereafter, while controlling the liquid temperature to 75 ° C. ± 1 ° C., 12.1 kg of styrene, 2.88 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 548 g of t-dodecyl mercaptan are added dropwise. After completion of the dropwise addition, the liquid temperature was raised to 80 ° C. ± 1 ° C. and stirring was performed for 6 hours. Next, the liquid temperature is cooled to 40 ° C. or lower, stirring is stopped, and the mixture is filtered through a pole filter, which is designated as “Latex (1) -A”.
[0179]
The glass transition temperature of the resin particles in the latex (1) -A was 57 ° C., the softening point was 121 ° C., the molecular weight distribution was weight average molecular weight = 17,000, and the weight average particle size was 120 nm.
[0180]
A solution obtained by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 l of ion-exchanged pure water is referred to as “anionic surfactant solution D”. Further, a solution obtained by dissolving 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct in 4.0 l of ion-exchanged water is referred to as “nonionic surfactant solution E”.
[0181]
A solution obtained by dissolving 200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) in 12.0 l of ion-exchanged water is referred to as “initiator solution F”.
[0182]
A WAL emulsion (polypropylene emulsion with a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration of 29.9%) was added to a 100-liter GL reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle. .41 kg, the total amount of “anionic surfactant solution D” and the total amount of “nonionic surfactant solution E” are added, and stirring is started. Next, 44.0 l of ion exchange water is added. Heating is started, and when the liquid temperature reaches 70 ° C., “initiator solution F” is added. Next, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 9.02 g of t-dodecyl mercaptan is dropped. After completion of the dropwise addition, the liquid temperature was controlled at 72 ° C. ± 2 ° C., and the mixture was heated and stirred for 6 hours. Furthermore, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature is cooled to 40 ° C. or lower and stirring is stopped. It filtered with the pole filter and this filtrate was set to "latex (1) -B".
[0183]
The glass transition temperature of the resin particles in latex {circle around (1)}-B was 58 ° C., the softening point was 132 ° C., the molecular weight distribution was weight average molecular weight = 245,000, and the weight average particle size was 110 nm.
[0184]
A solution obtained by dissolving 5.36 kg of sodium chloride as a salting-out agent in 20.0 l of ion-exchanged water is referred to as “sodium chloride solution G”.
[0185]
A solution obtained by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 l of ion-exchanged water is referred to as “nonionic surfactant solution H”.
[0186]
Into a 100 l SUS reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, a particle size and shape monitoring device, the latex {circle around (1)}-A = 20.0 kg and the latex {circle around (1)} − B = 5 prepared above. .2 kg, colorant dispersion 1 = 0.4 kg, and 20.0 kg of ion-exchanged water are added and stirred. Next, the mixture is heated to 40 ° C., and sodium chloride solution G, isopropanol (manufactured by Kanto Chemical Co.) 6.00 kg, and nonionic surfactant solution H are added in this order. Then, after standing for 10 minutes, the temperature rise was started, the temperature was raised to a liquid temperature of 85 ° C. in 60 minutes, and the particles were heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours while being salted out / fused. Grow. Next, 2.1 l of pure water is added to stop the particle size growth.
[0187]
In a 5 liter reaction vessel equipped with a temperature sensor, a cooling tube, a particle size and shape monitoring device, 5.0 kg of the fused particle dispersion prepared above was placed, and the liquid temperature was 85 ° C. ± 2 ° C. and 0.5 kg. The shape was controlled by heating and stirring for ˜15 hours. Then, it cools to 40 degrees C or less and stops stirring. Next, using a centrifugal separator, classification is performed in the liquid by a centrifugal sedimentation method, followed by filtration through a sieve having an opening of 45 μm. This filtrate is designated as an associated liquid (1). Subsequently, using a Nutsche, wet cake-like non-spherical particles were collected from the associated liquid (1) by filtration. Thereafter, it was washed with ion exchange water.
[0188]
The non-spherical particles were dried at a suction air temperature of 60 ° C. using a flash jet dryer and then dried at a temperature of 60 ° C. using a fluidized bed dryer. In the monitoring of the salting-out / fusion stage and the shape control process, by controlling the number of revolutions of stirring and the heating time, the coefficient of variation of the shape and the shape factor is controlled, and further the particle size and particle size distribution by subclassification By adjusting the coefficient of variation, colored particles 1 and 2 shown in Table 1 were obtained.
[0189]
Preparation of colored particles 3 (example of suspension polymerization method)
Styrene = 165 g, n-butyl acrylate = 35 g, carbon black = 10 g, di-t-butyl salicylic acid metal compound = 2 g, styrene-methacrylic acid copolymer = 8 g, paraffin wax (mp = 70 ° C.) = 20 g at 60 ° C. The mixture was uniformly dissolved and dispersed at 12000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and 2,2′-azobis (2,4-valeronitrile) = 10 g as a polymerization initiator was added thereto. In addition, it was dissolved to prepare a polymerizable monomer composition. Next, 450 g of 0.1 M sodium phosphate aqueous solution was added to 710 g of ion exchange water, and 68 g of 1.0 M calcium chloride was gradually added while stirring at 13,000 rpm with a TK homomixer to prepare a suspension in which tricalcium phosphate was dispersed. did. The polymerizable monomer composition was added to this suspension, and stirred at 10,000 rpm for 20 minutes with a TK homomixer to granulate the polymerizable monomer composition. Thereafter, the reaction was carried out at 75 to 95 ° C. for 5 to 15 hours using a reaction apparatus having a configuration of the stirring blade as shown in FIG. 4 (crossing angle α was 45 °). Tricalcium phosphate was dissolved and removed with hydrochloric acid, and then classified in a liquid by centrifugal sedimentation using a centrifugal separator, and then filtered, washed and dried.
[0190]
Monitoring during the polymerization, controlling the liquid temperature, stirring rotation speed, and heating time to control the variation coefficient of shape and shape factor, and further adjusting the variation coefficient of particle size and particle size distribution by classification in liquid Thus, colored particles 3 shown in Table 1 below were obtained.
[0191]
[Table 1]

[0192]
Toners 1 to 9 were prepared by adding the above colored particles 1 to 3 and the external additives shown in Tables 2, 3 and 4 below, and mixing them with a Henschel mixer under a rotation condition of 30 m / sec.
[0193]
[Table 2]

[0194]
[Table 3]

[0195]
* Titanium oxide 1: Titanium oxide treated with octyltrimethoxysilane
(Number average primary particle size = 15 nm)
* Titanium oxide 2: Titanium oxide treated with zinc stearate
(Number average primary particle size = 20 nm)
* Titanium oxide 3: Titanium oxide treated with zinc stearate
(Number average primary particle size = 40 nm)
[0196]
[Table 4]

[0197]
Preparation of developer
A developer composed of the following toner and carrier was prepared.
[0198]
Further, each of the “toner 1” to “toner 9” and a ferrite carrier coated with a silicone resin and having a volume average particle diameter of 60 μm were mixed to prepare a developer having a toner concentration of 6% and used for printing evaluation. . This developer is designated as “Developer 1” to “Developer 9” corresponding to the toner.
[0199]
Fabrication of a combination of a cleaning blade and plastic parts
As shown in Table 5, 14 types of combinations of cleaning blades and plastic members used in the cleaning device were produced. The cleaning blade and the plastic member were bonded with a double-sided tape.
[0200]
[Table 5]

[0201]
PET in the table: Polyethylene terephthalate film
Polyimide: Indicates a polyimide film.
[0202]
Cleaning conditions
A cleaning blade having a free length of 9 mm was brought into contact with the photosensitive member by a weight load method so that the linear pressure was 20 (N / m) in the counter direction with respect to the rotation direction.
[0203]
Evaluation
As an evaluation machine, Konica digital copying machine Konica 7075 (corona charging, laser exposure, reversal development, electrostatic transfer, nail separation, cleaning blade, cleaning auxiliary brush roller adoption process) is used, and the copying machine is listed in Table 6 The combination of the photoconductor, developer, and cleaning blade was mounted for evaluation. For cleaning performance and image evaluation, a character image having a pixel rate of 7%, a human face photo, a solid white image, and a solid black image were each copied into 1/4 equal original images on A4 neutral paper. The environmental conditions were considered to be the severest in a high-temperature and high-humidity environment (30 ° C., 80% RH), and 100,000 copies were continuously printed and evaluated using character images, halftone images, solid white images, and solid black images. Evaluation items and evaluation criteria are shown below.
[0204]
[Table 6]

[0205]
Evaluation criteria
Image blur (evaluated by a decrease in resolution of text image)
○: Image blur does not occur until the end of 100,000 copies
△: Slight image blur occurs before the end of 100,000 copies (decoding of characters is possible)
×: Significant image blur occurs before the end of 100,000 copies (characters cannot be decoded)
Cleanability (After 30,000, 50,000 and 100,000 copies have been copied, 10 consecutive copies are made on A3 paper, and determined by the occurrence of poor cleaning in the solid white area)
○: No filming due to toner slipping up to 100,000 sheets
Δ: No filming due to toner slipping up to 50,000 sheets
X: Filming occurs due to toner slipping on less than 30,000 sheets
Blade turning
○: No blade turning occurred during 100,000 copies
×: Blade turning occurred during 100,000 copies
Overall image quality (Evaluated after initial copy and 100,000 copies)
○: The character image is clear and the halftone image is smoothly reproduced both at the initial stage and after copying 100,000 sheets.
Δ: Initially good, but some blurring and roughness are observed in the character image after copying 100,000 sheets or the halftone image.
[0206]
X: Image blur and roughness are remarkable in a character image or halftone image after 100,000 copies.
[0207]
Cleaning blade vibration magnitude
Measurement method of vibration magnitude
The sensor of the acceleration detector NP-3210 manufactured by Ono Sokki Co., Ltd. is attached to the support member to which the cleaning blade is bonded, the vibration when the photosensitive member rotates at a constant rotation is read by the sensor for 10 seconds, and the output data from the sensor Was processed by an “ONO SOKKI CF6400 4-channel intelligent FF analyzer” to obtain an average value of the vibration amplitude, and this was expressed by the vibration magnitude (nm) of the blade.
[0208]
Photoreceptor film thickness reduction
The amount of wear of the photoconductor was determined by calculating the difference in the average film thickness of the photoconductor measured at the start of the live-action evaluation and at the end of copying 100,000 copies.
[0209]
Film thickness measurement method
As for the film thickness of the photosensitive layer, 10 portions of the uniform film thickness are randomly measured, and the average value is defined as the film thickness of the photosensitive layer. The film thickness measuring device was an eddy current type film thickness measuring device EDDY560C (manufactured by HELMUT FISCHER GMBTE CO).
[0210]
Other evaluation conditions
The other evaluation conditions using the digital copying machine Konica 7075 were set to the following conditions.
[0211]
Charging conditions
Charger: Scorotron charger, initial charge potential of -750V
Exposure conditions
Set the exposure amount so that the potential of the exposed area is -50V.
[0212]
Development conditions
DC bias; -550V
Transcription conditions
Transfer pole; corona charging method
The evaluation results are shown in Table 7.
[0213]
[Table 7]

[0214]
As is apparent from Table 7, the combination No. satisfying the requirements of the present invention. Nos. 1-8, 10-14, and 17-19 have no image blur, good cleaning properties, and little film thickness loss. On the other hand, a combination No. using a toner other than the present invention was used. No. 9 has noticeable image blurring, and No. 9 of the combination of the cleaning blade and the plastic member outside the present invention. Nos. 15, 21 and 22 show that the vibration of the cleaning blade is not effectively absorbed, the cleaning performance is deteriorated, and the image is blurred. In 16 and 20, the vibration of the cleaning blade becomes excessive, and the blade is turned up.
[0215]
【The invention's effect】
As is clear from the above-described embodiments, the present invention in which a cleaning blade having a plastic member and a developer are combined is effective in that the residual toner on the organic photoreceptor is not turned over and no toner slips out. Therefore, it is possible to provide an image forming method and an image forming apparatus which can be removed in an effective manner and have a good overall image quality.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an overall configuration of an image forming apparatus according to the present invention.
FIG. 2 is a configuration diagram of a cleaning device using the cleaning blade of the present invention.
FIGS. 3A and 3B are explanatory diagrams showing projected images of toner particles having no corners, and FIGS. 3B and 3C are explanatory diagrams showing projected images of toner particles having corners, respectively. FIGS.
FIG. 4 is a perspective view showing an example of a polymerized toner reaction device.
FIG. 5 is a cross-sectional view showing an example of a polymerized toner reaction device.
FIG. 6 is a schematic view showing a specific example of the shape of a stirring blade.
[Explanation of symbols]
121 photoconductor
122 Charger
123 Developer
124 Transfer device
125 separator
126 Cleaning device
126A Cleaning blade
126B Plastic member
127 PCL (precharge lamp)
130 Exposure optical system
191 Support member
a Free length of the cleaning blade
b Free length of plastic parts
t ₁ Cleaning blade thickness
t ₂ Thickness of plastic parts

Claims (5)

The electrostatic latent image formed on the organic photoreceptor is developed with a developer containing toner, and the toner image visualized by the development is transferred from the organic photoreceptor to a transfer material. In the image forming method in which the toner remaining on the surface is removed using a urethane rubber cleaning blade having a JISA hardness of 55 to 90 at 25 ± 5 ° C., the cleaning blade has a rebound resilience of 25 to 80, and its tip is organic. toward the rotation direction opposite to the direction of the photosensitive member (counter direction) is pressed against, adhered to the piezoelectric surface in contact with the surface on the opposite side, a plastic member of a polyethylene terephthalate or polyimide of the cleaning blade thickness 0.0 4 to 2 mm The free length a of the cleaning blade and the free length b of the plastic member satisfy the relationship of Formula 1 and the cleaning blade The thickness t _{1 of the} roller and the thickness t ₂ of the plastic member satisfy the relationship of Formula 2, and the toner used for the developer is added with fine particles in which inorganic fine particles are fixed on the surface of the resin particles to the colored particles. An image forming method, wherein the toner is a toner.
Formula 1
0.1 <b / a ≦ 0.9 (where a is 6 to 15 mm)
Formula 2
_{1/50 ≦ t 2 / t} 1 ≦ 1 ( where, _{t 1} is 0.5 to 10 mm)   2. The image forming method according to claim 1, wherein the number average particle diameter of fine particles obtained by fixing inorganic fine particles on the surface of the resin particles is 100 nm to 2000 nm.   The image forming method according to claim 1, wherein the amount of the fine particles added is 0.1 to 3.0% by mass in the toner.   4. The toner according to claim 1, wherein the toner further comprises 0.1 to 3.0% by mass of a fluidizing agent having a number average primary particle size of 5 to 49 nm. The image forming method described.   An image forming apparatus using the image forming method according to claim 1.

Images