JP3569640B2 - Non-magnetic one-component toner and developing method thereof - Google Patents

Description

本発明はさらに、層規制部材により、電荷の付与された非磁性一成分トナーの薄層を現像ローラまたは現像ベルトの表面に形成し、該現像ローラまたは現像ベルト表面のトナーを静電潜像を保持する感光体ドラムに接触させて静電潜像を現像し、ついで該トナーを被転写材に転写を行う接触型の非磁性一成分現像方法において、該非磁性一成分トナーが、結着樹脂および着色剤を主成分とし、かつ上記式（１）で示される構成単位を含むポリオレフィン系炭化水素化合物を含有し、該ポリオレフィン系炭化水素化合物は７０℃から１５０℃の範囲に融点を有するものであり、かつ結着樹脂の溶融粘度が８×１０^５poise未満の低粘度となる温度で溶融混練させて得られることを特徴とする非磁性一成分現像方法を提供する。
【０００７】
【発明の実施の形態】
本発明者らは、非磁性一成分トナーにおける前記の問題を解決すべく鋭意研究に努めた結果、トナーの帯電量の安定化、帯電量分布のシャープ化、帯電立ち上がり特性の向上が、前記問題の解決に重要な影響を与えることを見いだした。
カブリの発生には、主としてトナーの帯電不良が影響する。すなわち、極端に低い帯電量もしくは逆帯電したトナー粒子が原因となる場合がある。これらは、荷電制御剤や着色剤のトナー中での分散不良等が原因で含有量に偏りが存在し、それに伴って帯電不良が発生したり、あるいは主に粒子径分布における極端な大粒径及び小粒径のトナー粒子が、摩擦帯電、電荷注入等によって得られる帯電が不均一となり、十分な帯電量が得られない場合に多く発生する。従って、より均一な荷電効果もしくは帯電補助を目的とした場合、より均質分散の状態で荷電制御剤や着色剤をトナー中に存在させる必要性がある。しかし、トナー中に荷電制御剤、着色剤を分散させた場合、それらはトナー中において粒子状態で存在するため、分散性において限りがあるため、帯電を均一化することは難しい。
【０００８】
したがって本発明では、従来の荷電制御剤、着色剤に加えて、もしくはそれに代わって、均質な分散状態もしくは良好な混合状態でトナー中に存在可能な特定の材料、すなわち式（１）に示す構成単位を含有するポリオレフィン系炭化水素化合物を含有させることにより本発明の目的を達成できるトナーの提供に成功した。
本発明における特定のポリオレフィン系炭化水素化合物（以下荷電補助剤ともいう）の使用は、平均帯電量を大きく変化させることなく、低帯電量のトナーを減少し、かぶり、中抜けをなくし、細線再現性を向上し、トナー飛散を無くし、トナー消費量の悪化を防止でき、耐久性を向上させるのに有効性を発揮する。また、荷電補助剤の熱特性を変化させることで、トナーの定着特性をより向上させることもできる。
【０００９】
本発明の非磁性一成分トナーおよび該トナーを使用する現像方法に使用される現像装置の一例を図１に示す。
すなわち図１は、本発明の接触型現像の非磁性一成分トナーの現像方法に使用する現像装置の概略構成図である。図中、１は円筒状の静電潜像保持体である感光体ドラム、２はホッパー、３は非磁性一成分トナー、４はドクターブレードなどの層規制部材、５は現像ローラ、６はトナー供給ロール、７は撹拌機である。この現像装置において、感光体ドラム１の表面には、電子写真法によって静電潜像が形成される。ホッパー２内には非磁性一成分トナー３が収容されている。層規制部材４によって現像ローラ５の表面に形成されるトナー層は一定の層厚となるように制御され、かつ該トナーに電荷が付与される。現像ローラ５の表面に担持されたトナーは、感光体ドラムの表面に搬送される。その際非磁性一成分トナーは層規制部材４によって摩擦帯電される。この場合、層規制部材を直流または交流電源に接続し、現像ローラ５と層規制部材との間に電界が発生するようにしてもよい。現像ローラ５の表面に担持された非磁性一成分トナーは、現像ローラ５の回転により搬送されて、静電潜像を有する感光体ドラム１と接触し、静電潜像を顕像化する。その後、感光体ドラム１表面上に顕像化された非磁性一成分トナーは、紙などの被転写材に転写される。なお、図１では感光体ドラム１が円筒状のものであるがこれをベルト状の弾性を有するものとしてもよい。
【００１０】
被転写材に転写された非磁性一成分トナーは、図２に示す接触型加熱定着装置で定着することが好ましい。図２は接触型加熱定着装置の概略構成図であり、図中８は定着ローラ、９はヒータローラ、１０はヒートランプ、１１は剥離づめ、１２は被転写材である。被転写材１２に転写された非磁性一成分トナー３は、定着ローラ８とヒータローラ９との間で圧接され転写材に溶融固化される。
【００１１】
現像ローラ５は、ローラ全体がアルミニウム等の金属でできたものでもよいし、このような金属の表面にトナー担持層を形成したもの、またローラ全体が弾性体でできたもの、更にまたこのような弾性体の表面にトナー担持層を形成したものでもよい。
前記トナー担持層としては、適度の弾性を備えた、肉薄樹脂層、例えば、含フッ素樹脂、シリコーン系樹脂、ポリエステル樹脂、ポリカーボネート樹脂などの膜形成性を有する樹脂、各種ゴムが使用される。トナー担持層の厚さは、１０〜２００μm の範囲に形成される。また、トナー担持層は導電性塗料が塗布されたものであってもよい。また、トナー担持層は、バイアス電圧が印加できるように導電性の塗料よりなるか、または導電性の材料を含有させたものが好ましい。前記弾性材料としては、シリコーンゴム等の各種ゴム、スポンジゴム、ウレタンフォーム等が使用され、これらには導電性粉末が含有されていてもよい。また、図１では現像ローラ５がローラ状のものであるがこれをベルト状のものとしてもよい。
【００１２】
本発明の非磁性一成分トナーは結着樹脂、着色剤、荷電補助剤、必要に応じて、荷電制御剤、離型剤、その他の物質を含有した微粒子である。
上記結着樹脂としては、通常トナー用として使用される結着樹脂は、特に限定されることなく使用される。これらを例示すると次のとおりである。
ポリスチレン、ポリクロロスチレン、ポリ−α−メチルスチレン、スチレン−クロロスチレン共重合体、スチレン−プロピレン共重合体、スチレン−ブタジエン共重合体、スチレン−塩化ビニル共重合体、スチレン−酢酸ビニル共重合体、スチレン−マレイン酸共重合体、スチレン−アクリル酸エステル共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−アクリル酸オクチル共重合体、スチレン−アクリル酸フェニル共重合体等）、スチレン−メタクリル酸共重合体（スチレン−メタクリル酸メチル共重合体、スチレンーメタクリル酸エチル共重合体、スチレン−メタクリル酸ブチル共重合体、スチレン−メタクリル酸オクチル共重合体、スチレン−メタクリル酸フェニル共重合体等）、スチレン−α−クロルアクリル酸メチル共重合体およびスチレン−アクリロニトリル−アクリル酸共重合体等のスチレン系樹脂（スチレンまたはスチレン置換体を含む単独重合体または共重合体）、塩化ビニル樹脂、ロジン変性マレイン酸樹脂、フェノール樹脂、エポキシ樹脂、飽和ポリエステル樹脂、不飽和ポリエステル樹脂、低分子量ポリエチレン、低分子量ポリプロピレン、アイオノマー樹脂、ポリウレタン樹脂、シリコーン樹脂、ケトン樹脂、エチレン−エチルアクリレート共重合体、キシレン樹脂並びにポリビニルブチラール樹脂等。本発明において、特に好ましく使用される樹脂としては、スチレン系樹脂、飽和もしくは不飽和ポリエステル樹脂、および エポキシ樹脂等が挙げられる。これらの樹脂は、適宜２種以上混合して使用することもできる。
【００１３】
本発明で使用される結着樹脂としては、ゲルパーミエイションクロマトグラフィ（以後ＧＰＣという）により測定した分子量分布として下記の特性を有するものが特に好ましい。結着樹脂のテトラヒドロフラン（以下ＴＨＦと略す）可溶分の分子量が、ＧＰＣによって測定されるクロマトグラムにおいて、ピークが１つ以上存在し、その１つ以上のピークの内、最大のピークにおける分子量（以下ピークトップ分子量と略す）が１０，０００以下であるものが好ましい。
また、１つのピークは３，０００〜２０，０００、特に４，０００〜１５，０００にあるものが好ましい（以下このピークをＬピークと略す）。更にＬピークよりも高分子量側にピーク又はショルダーが１つ以上あり（以下このピークをＨピーク又はＨショルダーと略す）、更にＨピーク又はＨショルダーの位置は７，０００〜５００，０００、特に１２，０００〜２００，０００にあるものが好ましい。
Ｌピークの位置が３，０００より低いとブレード融着や現像ローラへのフィルミングが発生しやすくなり、耐久性が低下する。また、Ｌピークが２０，０００より高いと低温領域での定着性が悪化しやすくなる傾向にある。
Ｈピーク又はＨショルダーの位置が７，０００より低いと定着性は良好であるが、ホットオフセットが発生しやすくなり使用可能な定着温度幅がせまくなる。
なお、本発明において、結着樹脂の分子量分布は、ＧＰＣによって次の条件で測定された値である。すなわち、温度２５℃においてＴＨＦを毎分１ｍｌの流速で流し、濃度０．４ｇ／ｄｌのＴＨＦ試料溶液を試料重量として８ｍｇ注入し測定する。また、試料の分子量測定にあたっては、該試料の有する分子量分布が、数種の単分散ポリスチレン標準試料により作製された検量線の分子量の対数とカウント数が直線となる範囲内に包含される測定条件を選択する。また、本測定にあたり、測定の信頼性は上記の測定条件で行ったＮＢＳ７０６ポリスチレン標準試料（Ｍｗ＝２８．８×１０⁴、Ｍｎ＝１３．７×１０⁴、Ｍｗ／Ｍｎ＝２．１１）のＭｗ／Ｍｎが２．１１±０．１０となることにより確認できる。
【００１４】
着色剤としては、従来から用いられているものであれば、任意の適当な顔料や染料が使用できる。それらを例示すると次の通りである。
カーボンブラック、アニリンブルー、カルコオイルブルー、クロムイエロー、ウルトラマリンブルー、デュポンオイルレッド、キノリンイエロー、メチレンブルークロライド、フアロシアニンブルー、マラカイトグリーンオクサレート、ランプブラック、ローズベンガル、ローダミン系染顔料、アントラキノン染料、モノアゾおよびジスアゾ系染料等。着色剤の含有量が、現像により可視像を形成するに十分な量であればよく、例えば結着樹脂１００重量部に対し２〜２０重量部の量が好ましく使用される。
本発明で使用される荷電補助剤、すなわちポリオレフィン系炭化水素化合物としては、式（１）に示す構成単位を含むものであればよい。
このような化合物としては市販品として容易に入手でき、三井化学社製の商品名 ハイワックス１１１０Ｈ、１１２０Ｈ、１１４０Ｈ、１１６０Ｈ、２２３５Ｈ、４１１０Ｈ等を挙げることができる。
【００１５】
荷電補助剤は、融点が７０℃から１５０℃、好ましくは、９０℃から１３０℃であることがより好適である。融点が上記範囲の下限より低いと、低温領域での定着特性を悪化させる傾向にあり、融点が上記範囲の上限より高いと、トナー中での分散性が悪化し、帯電補助の効果が低下するばかりでなく、それ自体が脱離しやすくなり、画像不良を引き起こす傾向にある。
荷電補助剤は、結着樹脂１００重量部に対して０より多く２０重量部より少ない範囲で含有されていることが好ましく、更に３から１０重量部の範囲で含有させることが好ましい。含有量が上記範囲の下限では本発明の目的を達成することができなく、上限より多い場合ではトナー粒子の保存安定性に問題が生じる場合がある。
【００１６】
電荷を制御するための材料（荷電制御剤）を必要に応じ適宜配合することもできる。荷電制御剤としては次のものが例示される。
含金属アゾ染料、ニグロシン染料、第４級アンモニウム塩、トリフェニルメタン系制御剤、オイルブラック等の油溶性染料、ナフテン酸、サリチル酸、オクチル酸、およびこれらのマンガン、コバルト、鉄、亜鉛、アルミニウム、鉛等の金属塩、アルキルサリチル酸の金属キレート等。
トナーの熱特性や物理特性を改良する目的でトナー中に内添しうる助剤としては、公知のものが使用可能である。例えば、離型剤として、低分子量ポリプロピレン、低分子量ポリエチレン等のポリアルキレンワックス、パラフィンワックス、高級脂肪酸、脂肪酸アミド等が挙げられる。その添加量は、結着樹脂１００重量部に対して、０．１から１０重量部が好ましい。
また、感光体を保護すると共に、現像特性を劣化させることなく、高品質の画像を得るために、高級脂肪酸、高級脂肪酸金属塩類、オレフィン−無水マレイン酸共重合体類などを適宜添加してもよい。
【００１７】
本発明の非磁性一成分トナーは、結着樹脂、着色剤、荷電補助剤およびその他必要に応じて配合する物質を熱溶融混練、粉砕した後、分級することにより得ることができる。この場合、結着樹脂の溶融粘度が８×１０⁵poiseより低粘度となる温度で溶融混練させることが荷電補助剤を均質な分散状態で結着樹脂に含有させることができる。更に混練機中で先に溶融粘度が８×１０⁵poiseより高粘度となる温度で溶融混練させた後、溶融粘度が８×１０⁵poiseより低粘度となる温度まで昇温させ更に溶融混合して得た非磁性一成分トナーが極めて荷電補助剤を均質な分散状態で結着樹脂に含有させることができる。
ここでいう均質な分散状態とは、荷電補助剤であるオレフィン系炭化水素化合物と結着樹脂とを１対３の重量比でスライドグラス上で混合し、ホットプレートに載せ加温し、更に溶融攪拌後、放冷した際、肉眼で見える１ｍｍ以上の荷電補助剤によるボイドが２個以下となる状態をいい、このような均質な分散状態となる溶融混練温度で製造することが好ましい。
【００１８】
前記、製造方法において溶融混練する前に結着樹脂、着色剤、荷電補助剤及びその他必要に応じて配合する物質を下記の混合装置で撹拌・混合することが好ましい。混合装置の一例としては、Ｖ型混合機、ドラム型ミキサー、スーパーミキサー、ヘンシェルミキサー、ナウターミキサー、コーンミキサー等が挙げられる。また、結着樹脂と荷電補助剤の一部または全部を予め混合（予備混合）または、予備混合に続いて予備混練したものを用いてもよい。この際、予備混合は、上記公知の混合装置を用いる。また、予備混練は、一軸または二軸押出し式ニーダー、二本ロール等の加温可能な溶融混練可能な装置を用いる。
溶融混練は、結着樹脂、着色剤、荷電補助剤及びその他必要に応じて配合する物質を上記の装置で混合し、密閉式ニーダー、一軸または二軸の押し出し式混練機、二本ロール等で溶融混練し、冷却後、クラッシャー、ハンマーミル等で粗粉砕し、ジェットミル、クリプトロン等で微粉砕する。そして、風力分級機（例えば、エルボージェット、ＤＳセパレーター等）で分級すればよい。非磁性一成分トナーの体積平均粒径は、３〜１０μｍが細線再現性等高画質な画像が得られ好適である。非磁性一成分トナーの平均粒径は、コールターカウンター（コールター社製）等を用いて測定し、体積換算の平均粒子径として求めることができる。
また、非磁性一成分トナーはその表面に疎水性シリカ等の流動性向上剤等を付着させていてもよい。
【００１９】
【実施例】
以下、実施例及び比較例により本発明を更に詳細に説明する。尚、下記実施例中、単に「部」とあるものはいずれも「重量部」を意味するものである。
＜実施例１＞
ポリエステル系樹脂 …１００部
〔三井化学社製 ＸＰＥ−１９５４、ＧＰＣにより測定したＴＨＦ可溶分の分子量、ピークトップ分子量：６，５００、その他のピーク分子量：５０，０００、溶融粘度が８×１０⁵となる温度：１１５℃〕
含金属染料 … ２部
〔保土谷化学社製 ＴＲＨ〕
カーボンブラック … １０部
〔三菱化学社製 ＭＡ−１００〕
荷電補助剤 … ５部
〔三井化学社製 ハイワックス １１６０Ｈ、融点：７５℃〕
ポリプロピレン … ２部
〔三洋化成工業社製 ビスコール３３０Ｐ〕
上記材料をスーパーミキサーで混合後、エクストルーダーを用いて１２５℃で溶融混合し、冷却固化後、ジェットミル、風力分級機にて粉砕分級して平均粒子径＝８．５μｍの母体トナー粒子を作製した。この母体トナー粒子１００部に対して、シリカ粉末（日本アエロジル社製 Ｒ−８１２）１部をヘンシェルミキサーを用いて外添処理し、本発明のトナーを得た。
【００２０】
＜実施例２＞
実施例１において、荷電補助剤ハイワックス １１６０Ｈの含有量を５部から２部に変更し、更に、ワックス ＰＥ−１３０〔クラリアントジャパン社製〕２部を追加した以外は実施例１と同様にして本発明のトナーを得た。
【００２１】
【００２２】
【００２３】
＜実施例３＞
実施例１において、荷電補助剤ハイワックス １１６０Ｈの含有量を５部から２部に変更し、更に、ハイワックス ＮＬ８００〔三井化学社製〕を２部を追加した以外は実施例１と同様にして本発明のトナーを得た。
【００２４】
＜比較例１＞
実施例１において、荷電補助剤を使用しなかった以外は実施例１と同様にして比較用のトナーを得た。
【００２５】
＜比較例２＞
実施例２において、荷電補助剤ハイワックス１１６０Ｈのみを使用しなかった以外は実施例２と同様にして比較用のトナーを得た。
【００２６】
これらの実施例及び比較例で得られたトナーを図１および図２に示す構成の電子写真方式のレーザープリンター（セイコーエプソン株式会社製 ＬＰ−８３００）で８０００枚までの実写評価を行った。評価方法を次に示す。
画像濃度：直径３ｃｍのベタ画像をマクベス社製の反射濃度計ＲＤ−９１４で測定した。
細線再現性：２００ライン／インチのライン画像を５０倍のルーペで観察した。ライン画像の細り（カスレ）が５ケ所以内のものを良好、６ケ所以上のものを不良とした。
中抜け：ベタ画像を直径３ｃｍ視野の１０倍のルーペで観察し、白く抜けた部分が３個以下ならば無し、４個以上では有りとした。
汚れ：非画像部を直径３個視野の１０倍のルーペで観察し、黒斑状物の汚れが３個以下ならば無し、４個以上では有りとした。
実写評価の結果を表１に示す。
【００２７】
【表１】

【００２８】
本発明の実施例１〜３の非磁性一成分トナーは、白地部である非画像部の汚れおよびカブリが少なく、中抜けおよび細線再現性も良好な優れた画像を多数枚印字できた。これに対し、比較例１では、８０００枚後のカブリが多く、比較例２では初期画像から汚れ、カブリ、中抜けおよび細線再現性が悪く、実用に耐え得るものではなかった。
【００２９】
【発明の効果】
本発明によると、特定の接触型現像、接触加熱定着を行う非接触一成分現像方法において、白地部画像のカブリ、感光体上のカブリ、細線再現性、中抜けおよび耐久性が良好な非磁性一成分トナーおよび該トナーを使用した非磁性一成分現像方法が提供される。
【図面の簡単な説明】
【図１】接触型現像方法に使用する現像装置の説明図である。
【図２】接触型加熱定着装置の説明図である。
【符号の説明】
１ 感光体ドラム
３ 非磁性一成分トナー
４ 層規制部材
５ 現像ローラ
８ 定着ローラ
９ ヒータローラ
１２ 被転写材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a non-magnetic one-component toner containing a polyolefin-based hydrocarbon compound containing a specific structural unit, and a developing method using the toner. More specifically, the present invention relates to a non-magnetic one-component toner capable of providing a transferred image with less stain and fogging of a white background portion, less voids in an image portion, and excellent reproducibility of fine lines, and a developing method using the toner.
[0002]
[Prior art]
Development methods used in electrophotography and the like include a two-component development method and a one-component development method. The two-component developing method involves forming a magnetic brush by frictionally charging an insulating powder containing a binder resin as a main component, that is, an insulating toner and a magnetic carrier, and developing the electrostatic latent image formed on the photoconductor. How to The one-component developing method includes a magnetic one-component developing method and a non-magnetic one-component developing method. The magnetic one-component developing method is a method of developing with a magnetic one-component toner, and the non-magnetic one-component developing method is to form a non-magnetic one-component toner in a thin layer on a developing sleeve and contact or non-contact with a photoconductor. This is a development method.
[0003]
In the non-magnetic one-component developing method, similarly to the two-component developing method, it is necessary to impart a sufficient amount of charge to the toner in order to obtain a good image. It is also important to uniformly control the thickness of the non-magnetic one-component toner on the developing roller. In order to make the thickness of the toner on the developing roller uniform and to provide a sufficient amount of charge, a rubber or metal blade member is often pressed against the developing roller. In addition, a technique has been proposed in which a non-magnetic one-component toner is provided with a relatively high charge by including a charge control agent such as a metal-containing azo dye.
[0004]
However, if the pressing force of the blade member against the developing roller is weak, insufficient charging of the toner occurs. Insufficient charging of the toner causes problems such as low image density and high fog. Conversely, if the pressing force is too strong, the charge amount of the toner will be sufficient, but the blade member and the developing roller will be significantly worn. As a result, unevenness is generated on these surfaces, and the unevenness causes a problem that the force applied while the toner passes between the blade member and the developing roller becomes uneven, or that the developed layer becomes partially thick. . This problem results in a shortage of the partial charge amount of the toner, unevenness of image density and fog. There is also a problem that the toner is fused to the developing roller by a pressing force or heat.
Further, in recent years, there is a strong demand for higher definition of images in copiers, printers and the like. In order to meet the demand for higher definition, it has been proposed to reduce the toner particle diameter to 4 to 8 μm. However, when the toner particle diameter is reduced, various problems such as dirt and fog occur.
[0005]
[Problems to be solved by the invention]
When the toner particle diameter is reduced, smearing and fogging due to the toner adhering to a white background portion where no image is formed, a portion where toner particles are not present in an image when mainly forming a character or a line, a hollow defect phenomenon, and Problems such as deterioration of toner consumption, deterioration of toner scattering and durability, and deterioration of fixing characteristics due to the adhesion of toner to a portion of the body where no image is formed have been remarkable.
SUMMARY OF THE INVENTION An object of the present invention is to provide a toner which does not cause these problems and has excellent fine line reproducibility even if the toner particle diameter is reduced in a contact type non-magnetic one-component developing method.
[0006]
[Means for Solving the Problems]
According to the present invention, an electric charge is applied to a non-magnetic one-component toner by a layer regulating member, a thin layer of the toner is formed on the surface of a developing roller or a developing belt, and the toner on the surface of the developing roller or the developing belt is electrostatically charged. A non-magnetic one-component toner used in a contact-type non-magnetic one-component developing method in which an electrostatic latent image is developed by being brought into contact with a photosensitive drum that holds an image, and then the toner is transferred to a material to be transferred. The non-magnetic one-component toner contains a polyolefin-based hydrocarbon compound containing a binder resin and a colorant as main components and containing a structural unit represented by the following formula (1). A non-magnetic one-component toner having a melting point in the range of 150 ° C. and obtained by melt-kneading at a temperature at which the binder resin has a low viscosity of less than 8 × 10 ⁵ poise.
Embedded image

In the present invention, further, a thin layer of non-magnetic one-component toner to which electric charge is applied is formed on the surface of the developing roller or the developing belt by the layer regulating member, and the toner on the surface of the developing roller or the developing belt is formed into an electrostatic latent image. In a contact-type non-magnetic one-component developing method in which the electrostatic latent image is developed by contacting the photoreceptor drum to be held and then the toner is transferred to a transfer material, the non-magnetic one-component toner includes a binder resin and A polyolefin-based hydrocarbon compound containing a coloring agent as a main component and a structural unit represented by the above formula (1), wherein the polyolefin-based hydrocarbon compound has a melting point in the range of 70 ° C to 150 ° C. And a non-magnetic one-component developing method characterized by being obtained by melt-kneading at a temperature at which the binder resin has a low melt viscosity of less than 8 × 10 ⁵ poise.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors have conducted intensive studies to solve the above-mentioned problems in the non-magnetic one-component toner, and as a result, stabilization of the charge amount of the toner, sharpening of the charge amount distribution, and improvement of the charge start-up characteristics have been described. Has a significant effect on the solution of the problem.
The occurrence of fogging is mainly affected by poor charging of the toner. That is, an extremely low charge amount or a reversely charged toner particle may be a cause. These have a bias in the content due to poor dispersion of the charge control agent or the colorant in the toner, etc., resulting in poor charging, or an extremely large particle size mainly in the particle size distribution. In addition, toner particles having a small particle diameter are often generated when the charge obtained by frictional charging, charge injection, or the like becomes non-uniform and a sufficient charge amount cannot be obtained. Therefore, in order to achieve a more uniform charge effect or charge assist, it is necessary to make the charge control agent and the colorant exist in the toner in a more homogeneously dispersed state. However, when the charge control agent and the colorant are dispersed in the toner, they are present in a particle state in the toner, and therefore, the dispersibility is limited. Therefore, it is difficult to make the charge uniform.
[0008]
Accordingly, in the present invention, in addition to or instead of the conventional charge control agent and colorant, a specific material that can be present in the toner in a homogeneously dispersed state or in a good mixed state, that is, the structure represented by the formula (1) The present invention succeeded in providing a toner capable of achieving the object of the present invention by containing a polyolefin-based hydrocarbon compound containing a unit.
The use of a specific polyolefin-based hydrocarbon compound (hereinafter also referred to as a charge auxiliary) in the present invention reduces the amount of low-charged toner, eliminates fogging, voids, and reproduces fine lines without significantly changing the average charged amount. In addition, the toner can be prevented from scattering, the toner consumption can be prevented from deteriorating, and it is effective in improving the durability. Further, by changing the thermal characteristics of the charge auxiliary agent, the fixing characteristics of the toner can be further improved.
[0009]
FIG. 1 shows an example of the developing device used in the non-magnetic one-component toner of the present invention and a developing method using the toner.
That is, FIG. 1 is a schematic configuration diagram of a developing device used in the method for developing a non-magnetic one-component toner of the contact type development of the present invention. In the figure, 1 is a photosensitive drum which is a cylindrical electrostatic latent image holding member, 2 is a hopper, 3 is a non-magnetic one-component toner, 4 is a layer regulating member such as a doctor blade, 5 is a developing roller, 6 is a toner. The supply roll 7 is a stirrer. In this developing device, an electrostatic latent image is formed on the surface of the photosensitive drum 1 by electrophotography. The hopper 2 contains a non-magnetic one-component toner 3. The toner layer formed on the surface of the developing roller 5 by the layer regulating member 4 is controlled so as to have a constant thickness, and a charge is applied to the toner. The toner carried on the surface of the developing roller 5 is transported to the surface of the photosensitive drum. At this time, the non-magnetic one-component toner is frictionally charged by the layer regulating member 4. In this case, the layer regulating member may be connected to a DC or AC power source so that an electric field is generated between the developing roller 5 and the layer regulating member. The non-magnetic one-component toner carried on the surface of the developing roller 5 is conveyed by the rotation of the developing roller 5, comes into contact with the photosensitive drum 1 having an electrostatic latent image, and visualizes the electrostatic latent image. Thereafter, the non-magnetic one-component toner visualized on the surface of the photosensitive drum 1 is transferred to a transfer material such as paper. In FIG. 1, the photosensitive drum 1 has a cylindrical shape, but may have a belt-like elasticity.
[0010]
The non-magnetic one-component toner transferred to the transfer material is preferably fixed by a contact-type heat fixing device shown in FIG. FIG. 2 is a schematic configuration diagram of a contact-type heat fixing device. In the drawing, reference numeral 8 denotes a fixing roller, 9 denotes a heater roller, 10 denotes a heat lamp, 11 denotes a separation member, and 12 denotes a material to be transferred. The non-magnetic one-component toner 3 transferred to the transfer material 12 is pressed between the fixing roller 8 and the heater roller 9 to be melted and solidified on the transfer material.
[0011]
The developing roller 5 may be one in which the entire roller is made of a metal such as aluminum, one in which a toner carrying layer is formed on the surface of such a metal, one in which the entire roller is made of an elastic body, A toner carrying layer may be formed on the surface of a simple elastic body.
As the toner carrying layer, a thin resin layer having appropriate elasticity, for example, a film-forming resin such as a fluorine-containing resin, a silicone resin, a polyester resin, and a polycarbonate resin, and various rubbers are used. The thickness of the toner carrying layer is formed in the range of 10 to 200 μm. Further, the toner carrying layer may be coated with a conductive paint. Also, the toner carrying layer is preferably made of a conductive paint or containing a conductive material so that a bias voltage can be applied. As the elastic material, various rubbers such as silicone rubber, sponge rubber, urethane foam and the like are used, and these may contain a conductive powder. In FIG. 1, the developing roller 5 has a roller shape, but may have a belt shape.
[0012]
The non-magnetic one-component toner of the present invention is fine particles containing a binder resin, a colorant, a charge auxiliary, and if necessary, a charge control agent, a release agent, and other substances.
As the binder resin, a binder resin usually used for a toner is used without any particular limitation. These are exemplified as follows.
Polystyrene, polychlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer , Styrene-maleic acid copolymer, styrene-acrylate copolymer, styrene-methyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate Copolymers), styrene-methacrylic acid copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, Styrene-phenyl methacrylate copolymer), Styrene resins (homopolymers or copolymers containing styrene or styrene substituents) such as len-α-methyl methyl acrylate copolymer and styrene-acrylonitrile-acrylic acid copolymer, vinyl chloride resin, rosin-modified maleic Acid resin, phenol resin, epoxy resin, saturated polyester resin, unsaturated polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin and polyvinyl Butyral resin and the like. In the present invention, particularly preferably used resins include styrene resins, saturated or unsaturated polyester resins, and epoxy resins. These resins can be used as a mixture of two or more kinds.
[0013]
As the binder resin used in the present invention, those having the following characteristics as the molecular weight distribution measured by gel permeation chromatography (hereinafter referred to as GPC) are particularly preferable. In a chromatogram measured by GPC, one or more peaks are present in the molecular weight of the tetrahydrofuran (hereinafter abbreviated as THF) soluble component of the binder resin, and the molecular weight of the largest peak among the one or more peaks ( (Hereinafter abbreviated as peak top molecular weight) is preferably 10,000 or less.
One peak is preferably in the range of 3,000 to 20,000, particularly 4,000 to 15,000 (hereinafter, this peak is abbreviated as L peak). Furthermore, there is one or more peaks or shoulders on the higher molecular weight side than the L peak (hereinafter, this peak is abbreviated as H peak or H shoulder), and the position of the H peak or H shoulder is 7,000 to 500,000, particularly 12 Those in the range of 2,000 to 200,000 are preferred.
If the position of the L peak is lower than 3,000, blade fusion and filming on the developing roller are likely to occur, and the durability is reduced. On the other hand, if the L peak is higher than 20,000, the fixability in a low-temperature region tends to deteriorate.
If the position of the H peak or H shoulder is lower than 7,000, the fixability is good, but hot offset is apt to occur and the usable fixing temperature range is narrowed.
In the present invention, the molecular weight distribution of the binder resin is a value measured by GPC under the following conditions. That is, THF is allowed to flow at a flow rate of 1 ml per minute at a temperature of 25 ° C., and 8 mg of a THF sample solution having a concentration of 0.4 g / dl is injected as a sample weight for measurement. When measuring the molecular weight of the sample, the molecular weight distribution of the sample is within a range in which the logarithm of the molecular weight and the count number of a calibration curve prepared from several types of monodisperse polystyrene standard samples are linear. Select In this measurement, the reliability of the measurement was based on the NBS706 polystyrene standard sample (Mw = 28.8 × 10 ⁴ , Mn = 13.7 × 10 ⁴ , Mw / Mn = 2.11) performed under the above measurement conditions. It can be confirmed that Mw / Mn is 2.11 ± 0.10.
[0014]
As the colorant, any suitable pigments and dyes can be used as long as they are conventionally used. Examples are as follows.
Carbon black, aniline blue, calco oil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, rhodamine dyes and pigments, anthraquinone dyes , Monoazo and disazo dyes. The content of the colorant may be an amount sufficient to form a visible image by development, and for example, an amount of 2 to 20 parts by weight based on 100 parts by weight of the binder resin is preferably used.
The charge auxiliary agent used in the present invention, that is, the polyolefin-based hydrocarbon compound may be any as long as it contains the structural unit represented by the formula (1).
Such a compound can be easily obtained as a commercial product, and may be, for example, high wax 1110H, 1120H, 1140H, 1160H, 2235H, 4110H, and the like manufactured by Mitsui Chemicals, Inc.
[0015]
It is more preferable that the charging auxiliary has a melting point of 70 to 150 ° C, preferably 90 to 130 ° C. When the melting point is lower than the lower limit of the above range, there is a tendency that the fixing characteristics in the low temperature region are deteriorated. When the melting point is higher than the upper limit of the above range, the dispersibility in the toner is deteriorated, and the effect of the charge assisting is reduced. Not only that, it tends to detach itself, which tends to cause image defects.
The charge auxiliary is preferably contained in a range of more than 0 and less than 20 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the binder resin. If the content is lower than the above range, the object of the present invention cannot be achieved. If the content is higher than the upper limit, a problem may occur in the storage stability of the toner particles.
[0016]
A material (charge control agent) for controlling electric charge can be appropriately compounded as needed. The following are examples of the charge control agent.
Metal-containing azo dyes, nigrosine dyes, quaternary ammonium salts, triphenylmethane-based control agents, oil-soluble dyes such as oil black, naphthenic acid, salicylic acid, octylic acid, and their manganese, cobalt, iron, zinc, aluminum, Metal salts such as lead, metal chelates of alkyl salicylic acid, and the like.
As an auxiliary agent that can be internally added to the toner for the purpose of improving the thermal characteristics and physical characteristics of the toner, known auxiliary agents can be used. For example, examples of the release agent include polyalkylene waxes such as low-molecular-weight polypropylene and low-molecular-weight polyethylene, paraffin wax, higher fatty acids, and fatty acid amides. The addition amount is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the binder resin.
Also, while protecting the photoreceptor, without deteriorating the development characteristics, in order to obtain a high quality image, higher fatty acids, higher fatty acid metal salts, olefin-maleic anhydride copolymers and the like may be appropriately added. Good.
[0017]
The non-magnetic one-component toner of the present invention can be obtained by hot-melt kneading, pulverizing, and then classifying a binder resin, a colorant, a charge auxiliary and other substances to be added as required. In this case, the charge assistant can be contained in the binder resin in a homogeneously dispersed state by melt-kneading at a temperature at which the melt viscosity of the binder resin becomes lower than 8 × 10 ⁵ poise. Furthermore, after melt-kneading at a temperature at which the melt viscosity is higher than 8 × 10 ⁵ poise in a kneader, the temperature is increased to a temperature at which the melt viscosity becomes lower than 8 × 10 ⁵ poise, and further melt-mixed. The non-magnetic one-component toner thus obtained can contain the charge auxiliary in the binder resin in a very homogeneously dispersed state.
The term "homogeneous dispersion state" as used herein means that an olefinic hydrocarbon compound as a charge auxiliary and a binder resin are mixed on a slide glass at a weight ratio of 1: 3, placed on a hot plate, heated, and further melted. After stirring, when left to cool, it refers to a state in which two or less voids due to a charge auxiliary agent having a size of 1 mm or more that are visible to the naked eye are obtained, and it is preferable to manufacture at a melting and kneading temperature at which such a homogeneous dispersion state is obtained.
[0018]
It is preferable to stir and mix the binder resin, the colorant, the charge auxiliary agent and other substances to be compounded as required before melt-kneading in the above-mentioned production method using the following mixing apparatus. Examples of the mixing device include a V-type mixer, a drum mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a cone mixer. Further, a binder resin and a part or all of the charge auxiliary agent may be preliminarily mixed (preliminary mixing) or may be preliminarily kneaded after the preliminary mixing. At this time, the above-mentioned known mixing device is used for the preliminary mixing. For the preliminary kneading, a device capable of melting and kneading which can be heated, such as a single-screw or twin-screw extruder, a twin roll, or the like is used.
Melt kneading is carried out by mixing the binder resin, colorant, charge auxiliary agent and other substances to be compounded as necessary with the above-mentioned device, and using a closed kneader, a single-screw or twin-screw extrusion kneader, a two-roll etc. After melt-kneading and cooling, the mixture is coarsely pulverized by a crusher, a hammer mill or the like, and finely pulverized by a jet mill, a kryptron or the like. Then, classification may be performed with an air classifier (for example, an elbow jet, a DS separator, or the like). The volume average particle diameter of the non-magnetic one-component toner is preferably 3 to 10 μm because high quality images such as fine line reproducibility can be obtained. The average particle diameter of the non-magnetic one-component toner can be measured using a Coulter counter (manufactured by Coulter Co., Ltd.) or the like, and can be determined as an average particle diameter in terms of volume.
The non-magnetic one-component toner may have a fluidity improver such as hydrophobic silica adhered to the surface thereof.
[0019]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, in the following Examples, all "part (s)" means "part (s) by weight".
<Example 1>
Polyester resin: 100 parts [XPE-1954, manufactured by Mitsui Chemicals, Inc., molecular weight of THF-soluble component measured by GPC, peak top molecular weight: 6,500, other peak molecular weight: 50,000, melt viscosity is 8 × 10 ⁵ Temperature: 115 ° C]
Metallic dyes: 2 parts [TRH made by Hodogaya Chemical Co., Ltd.]
Carbon black: 10 parts [MA-100 manufactured by Mitsubishi Chemical Corporation]
Charge auxiliary agent: 5 parts [Mitsui Chemicals high wax 1160H, melting point: 75 ° C]
Polypropylene: 2 parts (Viscol 330P manufactured by Sanyo Chemical Industries, Ltd.)
The above materials are mixed by a super mixer, melt-mixed at 125 ° C. using an extruder, cooled and solidified, and then pulverized and classified by a jet mill or an air classifier to produce base toner particles having an average particle size of 8.5 μm. did. One part of silica powder (R-812 manufactured by Nippon Aerosil Co., Ltd.) was externally added to 100 parts of the base toner particles using a Henschel mixer to obtain a toner of the present invention.
[0020]
<Example 2>
In Example 1, in the same manner as in Example 1 except that the content of the charging auxiliary high wax 1160H was changed from 5 parts to 2 parts, and 2 parts of wax PE-130 (manufactured by Clariant Japan Co.) were further added. The toner of the present invention was obtained.
[0021]
[0022]
[0023]
<Example 3 >
Example 1 In the same manner as in Example 1 except that the content of the charging aid High Wax 1160H was changed from 5 parts to 2 parts, and 2 parts of High Wax NL800 (manufactured by Mitsui Chemicals, Inc.) were added. The toner of the present invention was obtained.
[0024]
<Comparative Example 1>
A comparative toner was obtained in the same manner as in Example 1 except that the charge auxiliary agent was not used.
[0025]
<Comparative Example 2>
Comparative Example 2 A toner for comparison was obtained in the same manner as in Example 2 except that only the charge auxiliary agent High Wax 1160H was not used.
[0026]
The toners obtained in these Examples and Comparative Examples were evaluated for actual printing up to 8000 sheets using an electrophotographic laser printer (LP-8300, manufactured by Seiko Epson Corporation) having the configuration shown in FIGS. The evaluation method is shown below.
Image density: A solid image having a diameter of 3 cm was measured with a reflection densitometer RD-914 manufactured by Macbeth.
Fine line reproducibility: A line image of 200 lines / inch was observed with a 50 × loupe. Line images with less than 5 thin spots (blurring) were good, and those with more than 6 spots were bad.
Hollow-out: A solid image was observed with a loupe 10 times the visual field of 3 cm in diameter.
Stain: A non-image portion was observed with a loupe having a diameter of 3 and 10 times the visual field.
Table 1 shows the results of the actual shooting evaluation.
[0027]
[Table 1]

[0028]
The non-magnetic one-component toners of Examples 1 to 3 of the present invention were able to print a large number of excellent images with less stains and fog in the non-image portion, which is a white background portion, and with good hollow and fine line reproducibility. On the other hand, in Comparative Example 1, the fog after 8000 sheets was large, and in Comparative Example 2, the initial image was poor in stain, fog, hollow, and fine line reproducibility, and was not practically usable.
[0029]
【The invention's effect】
According to the present invention, in a non-contact one-component developing method in which specific contact-type development and contact heating and fixing are performed, a non-magnetic material having good fog on an image on a white background, fog on a photoreceptor, fine line reproducibility, hollowness, and durability is excellent. A one-component toner and a non-magnetic one-component developing method using the toner are provided.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a developing device used for a contact type developing method.
FIG. 2 is an explanatory diagram of a contact-type heat fixing device.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 photosensitive drum 3 non-magnetic one-component toner 4 layer regulating member 5 developing roller 8 fixing roller 9 heater roller 12 transfer material

Claims (3)

The layer regulating member applies a charge to the non-magnetic one-component toner, forms a thin layer of the toner on the surface of the developing roller or the developing belt, and holds the toner on the developing roller or the developing belt surface as an electrostatic latent image. A non-magnetic one-component toner used in a contact-type non-magnetic one-component developing method in which an electrostatic latent image is developed by being brought into contact with a photosensitive drum, and then the toner is transferred to a material to be transferred. The toner contains a polyolefin-based hydrocarbon compound containing a binder resin and a colorant as main components and containing a structural unit represented by the following formula (1), wherein the polyolefin-based hydrocarbon compound is in a temperature range of 70 ° C to 150 ° C. A non-magnetic one-component toner obtained by melt-kneading at a temperature at which the binder resin has a low viscosity of less than 8 × 10 ⁵ poise.

2. The non-magnetic one-component toner according to claim 1, wherein the polyolefin-based hydrocarbon compound is contained in an amount of more than 0 and less than 20 parts by weight based on 100 parts by weight of the binder resin. A photoreceptor drum that forms a thin layer of non-magnetic one-component toner to which a charge is applied by a layer regulating member on the surface of a developing roller or a developing belt, and holds the toner on the developing roller or the developing belt surface as an electrostatic latent image A non-magnetic one-component developing method of developing an electrostatic latent image by contacting the toner with a toner, and then transferring the toner to a material to be transferred, wherein the non-magnetic one-component toner contains a binder resin and a colorant as main components. And a polyolefin-based hydrocarbon compound containing a structural unit represented by the following formula (1), wherein the polyolefin-based hydrocarbon compound has a melting point in the range of 70 ° C. to 150 ° C .; A non-magnetic one-component developing method characterized by being obtained by melt-kneading at a temperature at which the melt viscosity of the compound is as low as less than 8 × 10 ⁵ poise.

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