JP3666323B2 - Full color image forming method - Google Patents

Description

【００３１】
（式中、Ｒ₁ 〜Ｒ₄ は炭化水素基を示し、Ｘ⁺ はカチオンを示す。）
一般式［Ｉ］で表される化合物の内、Ｒ₁ 〜Ｒ₄ は置換されていてもよい炭化水素基を表すが、該炭化水素基の具体例としては、メチル基、エチル基、プロピレン基、イソプロピル基等のアルキル基、シクロヘキシル基、シクロペンチル基等のシクロアルキル基、ビニル基、アリル基等のアルケニル基、フェニル基、ナフチル基等の芳香族炭化水素基が挙げられる。また、これら炭化水素は置換されていてもよいが、該置換基としては、ハロゲン原子、水酸基、シアル基、アルキル基、アルケニル基、アルコキシ基が好ましい。
【００３２】
Ｒ₁ 〜Ｒ₄ のうち、少なくとも２つが芳香族炭化水素基であり、Ｘ⁺ がアルカリ金属イオンであるものが好ましい、更に、市販のものとしては、日本カーリット社製ＬＲ−１４７として知られている化合物、即ちＲ₁ 〜Ｒ₄ がすべてフェニル基であり、Ｘ⁺ がカリウムイオンであるのが特に好ましい。
これら、ホウ素化合物の帯電制御剤の添加量としては、結着樹脂１００重量部に対して０．０５から８重量部が好ましく、更に好適には０．１〜５重量部がよい。
【００３３】
前述の黒色トナーの帯電制御剤に用いられるアゾ系金属化合物の金属成分としては、クロムまたは鉄が好ましい。
これらアゾ系金属化合物の帯電制御剤の添加量としては、結着樹脂１００重量部に対して０．０５〜１０重量部が好ましく、更に好適には０．１〜６重量部がよい。
また、本発明に使用されるクロム・アゾ系化合物としては、下記一般式［II］で表されるものが好ましく、市販されているものとしては、例えば、オリエント化学工業社製ボントロンＳ−３４、Ｓ−５４、保土谷化学工業社製Ｔ−９５等が知られている。
【００３４】
【化５】

【００３５】
（式中、Ａ〜Ｄは同一であっても異なっていてもよく、置換されていてもよいベンゼン環を表す。また、Ｘ⁺ はカチオンを表す。）
一般式［II］においてＡ〜Ｄのベンゼン環の置換基としては、アルキル基、ハロゲン原子、シアノ基、ニトロ基、水酸基、アルコキシ基が好ましく、塩素原子が更に好ましい。
また、Ｘ⁺ はカチオンを表すが、水素イオン、アルカリ金属イオン、アンモニウムイオンが好ましい。
また、本発明に使用される鉄・アゾ系化合物としては、下記一般式［III ］で表される化合物が好ましく、市販されているものとしては、例えば、保土谷化学工業社製Ｔ−７７などが知られている。
【００３６】
【化６】

【００３７】
（式中、Ｅ〜Ｊは同一でも異なっていてもよく、置換されていてもよいベンゼン環を表す。また、Ｘ⁺ はカチオンを表す。）
一般式［III ］において、Ｅ〜Ｊのベンゼン環に置換基を有している場合、その置換基として、ハロゲン原子、スルホンアミド基、メシル基、スルホン酸基、水酸基、アミノ基、アルコキシカルボニル基、アセチルアミノ基、ベンゾイルアミノ基、置換されていてもよい炭化水素基、置換されていてもよいアルコキシ基を表し、該置換基は、アルキル基、アルケニル基、ハロゲン原子、シアノ基、水酸基、アミノ基、ニトロ基が好ましく、ハロゲン原子、アルコキシ基が更に好ましく、塩素原子、メトキシ基が特に好ましい。
また、Ｘ⁺ はカチオンを表すが、水素イオン、アルカリ金属イオン、アンモニウムイオンが好ましく、ナトリウムイオン、カリウムイオンが更に好ましい。
【００３８】
着色剤や帯電制御剤は、トナー中での分散性、相溶性を改良するためにあらかじめ樹脂との前混練などによって予備分散処理、いわゆるマスターバッチ処理や、顔料生成反応後の顔料分散液に樹脂を投入し顔料生成時の分散媒と樹脂を置換し混合することによる高濃度の顔料分散処理、いわゆるフラッシング処理を行ってもよい。これら処理品中の顔料粒子径は、可視光の半波長（２００ｎｍ）程度に分散させることで、カラー画像の透明性などを有利にすることができる。また、これら処理品自体の粒径は結着樹脂と同じ程度の粒径が好ましく、粒径が大きすぎると連続製造時にトナー中の着色剤の偏在を引き起こしやすくなる。通常、マスターバッチ処理品、フラッシング処理品の粒径としては３ｍｍ目開きの篩いをパス、好ましくは２ｍｍ以下の目開きの篩いをパスさせたものがよい。
本発明ではその他添加剤として、公知の各種有機又は無機の微粒子粉末をトナーの粘着性、凝集性、流動性、帯電性、表面抵抗などを改質の目的で使用してもよい。
【００３９】
トナー表面に添加する微粉末、いわゆる外添剤としては、少なくともシランカップリング剤、シリコンオイルで表面処理された無機微粉末がよい。これら表面処理剤では無機微粉末に疎水性、流動性、帯電性が付加され、非磁性１成分トナーでの負荷電性の帯電立ち上がりがよく、良好な帯電特性を得ることができるのでよい。
無機微粉末のコアとしては、公知の湿式或いは乾式で作製されるシリカ、チタニア、アルミナ、酸化亜鉛、酸化マグネシウム、マグネタイト、フェライト等より選択して使用できるが、好ましくはシリカ、チタニア、アルミナが好適であり、更に好ましくはシリカが最も好適である。
【００４０】
非磁性１成分系トナーの場合、無機微粉末は１種でもよいが、好ましくは粒子の大きさの異なる２種以上を併用した方が好適である。
特に、非磁性１成分系負荷電性トナーで無機微粉末を２種以上を併用する場合には、比較的粗い無機微粉末（ａ）と比較的細かい無機微粉末（ｂ）とを用い、少なくとも無機微粉末のどちらか一方をシリコンオイルで表面処理すればよい。粗い無機微粉末（ａ）の大きさはＢＥＴ法比表面積８０ｍ² ／ｇ未満が好ましく、より好ましくは５〜７９ｍ² ／ｇが好適であり、細かい無機微粉末（ｂ）の大きさはＢＥＴ法比表面積８０ｍ² ／ｇ以上が好ましく、より好ましくは８０〜５００ｍ² ／ｇが好適である。更には、無機微粉末（ａ）の表面処理剤がシリコンオイルで、無機微粉末（ｂ）の表面処理剤がシリコンオイル又はカップリング剤であることがより好適に使用される。
【００４１】
比較的粗い無機粉末（ａ）はトナーの耐ブロッキング性を向上し、及び現像槽内でのトナー粒子同士の及びトナー粒子と現像槽構成部材（壁、現像ロール、層厚み規制部材など）との凝集抑制、機械的衝撃緩和によるトナーの微粉砕化の抑制、外添剤の埋まり込み抑制、感光体へのフィルミング防止、トナー層厚み規制部材への付着現象の抑制、などの効果があると推定しており、これらの効果により貯蔵安定性に優れ、連続印字で使用しても画像劣化、トナー飛散・漏れによる機内汚れが起こりにくいなど耐久性性能が向上する。ＢＥＴ比表面積が８０ｍ² ／ｇ以上の場合には、トナー同士及び現像槽部材との隔壁としての無機微粉末（ａ）の役割が発揮されにくく、耐ブロッキング性が悪化し、連続印字時の耐久性能が悪化する傾向にある。無機微粉末（ａ）の表面処理剤としてシリコンオイルを使用することは、疎水化機能を付与して環境依存性を改善すると共に、トナーの帯電性を阻害しにくいので好ましく、特に未処理に対してシリコンオイル処理した無機微粉末（ａ）では負荷電性トナーの帯電の立ち上がりが良くなり、感光体上のかぶり、普通紙白地部のかぶりが向上する。シリコンオイル以外の表面処理剤では、トナーへの帯電特性を阻害しやすい傾向にある。
【００４２】
比較的細かい無機微粉末（ｂ）は、トナー流動性の改善、及び現像槽内でのトナー搬送性の向上などの効果があると推定しており、これらの効果によりトナーの補給性が優れ、現像部でのトナー層が均一化し、画像部が緻密で均一で良好であるなど高画質印字物を得られる。ＢＥＴ比表面積が８０ｍ² ／ｇ未満の場合には、無機微粉末（ｂ）のトナー流動性の改善効果が弱まり、ひいてはトナー補給性の悪化し、高画質印字物が得られなくなる傾向にある。無機微粉末（ｂ）の表面処理剤としては、シランカップリング剤またはシリコンオイルを使用する疎水性機能を付与し、環境依存性を改善すると共に、無機微粉末の流動性改善機能に優れている。シランカップリング剤またはシリコンオイル以外の表面処理剤では、流動性改善機能が劣る傾向にある。
【００４３】
無機微粉末（ａ）及び無機微粉末（ｂ）のコアは、同じ種類でも、異なった種類でもよい。
無機微粉末のシリコンオイルによる表面処理は従来公知の方法が用いられ、例えばシリコンオイルとしては、一般的なストレートシリコンオイルであるジメチルシリコンオイル、メチルフェニルシリコンオイル、メチルハイドロジェンシリコンオイル、及び変性シリコンオイルであるメタクリル酸変性シリコンオイル、エポキシ変性シリコンオイル、フッ素変性シリコンオイル、ポリエーテル変性シリコンオイル、アミノ変性シリコンオイル等があり、１種又は２種以上の混合物で用いられる。シリコンオイルとして好ましくは、ストレートシリコンオイルで、その中でもジメチルシリコンオイルが好適である。
【００４４】
無機微粉末のシランカップリング剤による表面処理も従来公知の方法が用いられ、例えばシランカップリング剤には、オルガノアルコキシラン（メトキシトリメチルシラン、ジメトキシアルコキシラン、トリメトキシメチルシラン、エトキシトリメチルシランなど）、オルガノクロルシラン（トリクロルメチルシラン、ジクロルジメチルシラン、クロルトリメチルシラン、、トリクロルエチルシラン、ジクロルジエチルシラン、クロルトリエチルシラン、トリクロルフェニルシランなど）、オルガノシラザン（トリエチルシラザン、トリプロピルシラザン、トリフェニルシラザン、ヘキサメチルジシラザン、ヘキサエチルジシラザン、ヘキサフェニルジシラザンなど）、オルガノジシラザン、オルガノシラン等があり、これらは１種或いは２種以上の混合物で用いられる。シランカップリング剤として好ましくは、オルガノクロルシラン、オルガノシラザンである。また、シランカップリング剤で処理した後にシリコンオイルの表面処理したりして、シランカップリング剤とシリコンオイルの表面処理は併用してもよい。
【００４５】
なお、無機微粉末のＢＥＴ法比表面積は市販されている窒素吸着によるＢＥＴ比表面積測定装置を用いて測定することができ、例えば、（株）島津製作所製流動式比表面積自動測定装置（フローソープ２３００形）などがある。また、無機微粉末の平均粒径は、透過型電子顕微鏡で粒子が識別できる高倍率（例えば、５万倍以上）で撮影した画像より粒子径を測定すればよい。
【００４６】
外添剤としての無機微粉末の添加重量部（Ｗ₀ ）は、トナー粒子を１００重量部とした際の被覆率ｆが２０〜４００％が好ましく、更には３０〜３００％が好適である。２種の無機微粉末を併用する場合には、粗い無機微粉末（ａ）の添加重量部（Ｗ_a ）と細かい無機微粉末（ｂ）の添加重量部（Ｗ_b ）の和が総添加重量部をＷ₀ とすればよい。総添加重量部（Ｗ₀ ）が、この範囲より少ないと無機微粉末の本来の効果を発揮せず好ましくなく、また、多過ぎると感光体フィルミングが発生し易く、感光体上かぶり、普通紙白地かぶりが悪化しやすいなど画像欠陥を引き起こし易くなり好ましくない。更に、無機微粉末（ａ）の添加重量部（Ｗ_a ）と無機微粉末（ｂ）の添加重量部（Ｗ_b ）は、Ｗ_a がＷ_b より多い方が非磁性１成分系トナーで比較的粗い無機微粉末の効果を強く発揮でき好ましく、特にＷ_a がＷ_b より０．２重量部多目でることがより好ましい。無機微粉末（ａ) と無機微粉末（ｂ）それぞれの添加重量部としては、各々単独での被覆率ｆを算出し、それぞれの被覆率がｆ≦３００、好適にはｆ≦２００であることが好ましく、これ以上であると無機微粉末（ａ）と（ｂ）のそれぞれの効果を発揮しにくく、画像欠陥など引き起こし易くなる傾向にある。
トナー粒子に１種の無機微粉末で混合した場合の被覆率ｆは、次式［Ｉ］で算出する。
【００４７】
【数１】

【００４８】
なお、式［Ｉ］中ｆは被覆率（％）、Ｄ_t はトナー粒子の体積平均粒径（μｍ）、ｄ_a 、ｄ₀ は無機微粉末の平均粒径（μｍ）、ρ_t 、ρ₀ はトナー粒子、無機微粉末のそれぞれの真比重とする。
また、トナー粒子に２種の無機微粉末（ａ）と（ｂ）で混合した場合の被覆率ｆは、次式［II］で算出する。
【００４９】
【数２】

【００５０】
なお、式［II］中ｆは被覆率（％）、Ｄ_t はトナー粒子の体積平均粒径（μｍ）、ｄ_a 、ｄ_b は無機微粉末（ａ）、無機微粉末（ｂ）のそれぞれの平均粒径（μｍ）、ρ_t 、ρ_a 、ρ_b はトナー粒子、無機微粉末（ａ）、無機微粉末（ｂ）のそれぞれの真比重とする。
トナーのその他外添剤としては、抵抗調整剤、研磨剤、帯電性調整剤などの目的で公知の各種有機および無機微粒子が挙げられ、例えばポリフッ化ビニリデン、ポリテトラフルオロエチレンなどのフッ素系樹脂粉末、ステアリン酸亜鉛、ステアリン酸カルシウムなどの脂肪酸金属塩、ポリメチルメタクリレートやシリコーン樹脂などを主成分とする樹脂ビーズ類、タルク、ハイドロタルサイトなどの鉱物類、チタン酸ストロンチウム等の強誘電体微粉末、導電性チタニアなどの導電性微粉末などが挙げられる。これらの量は、トナー粒子１００重量部に対し０．０１〜１０重量部が好ましい。
【００５１】
本発明に用いられるトナーは、従来公知の方法を含めて各種製造法で製造可能だが、一般的製造法としては次の例が挙げられる。
(1) 樹脂、帯電制御物質、着色剤および必要に応じて加えられる添加剤を機内に羽根、スクリューなどの回転部を有する混合装置で均一に分散する。混合装置としては、三井鉱山社製ヘンシェルミキサー、マツボー社製レーディゲーミキサー、ホソカワミクロン社製ナウターミキサー、カワタ社製スーパーミキサーなど、また容器自体が回転する一般のＶ型混合機等が使用できる。
【００５２】
(2) 分散物をニーダー、エクストルーダー、ロールミルなどで溶融混練する。混練装置としては、連続式の押出機、例えばＷ＆Ｐ社製ＺＳＰ型押出機、ＢＵＳＳ社製コニーダー、東芝機械社製ＴＥＭ型押出機、池貝社製ＰＣＭ型押出機、三井鉱山社製ニーデックスなど、一般のバッチ式混練機も使用できる。混練後の冷却装置としては、三井鉱山社／三菱化学エンジニアリング社製ドラムクーラー、ＮＢＣ社製ベルトクーラーなどが使用できる。
(3) 混練物を粗粉砕機で粗粉砕した後、微粉砕機で微粉砕する。粉砕機としては、ＮＰＫ社製Ｉ型・ＩＤＳ型ジェットミル、ホソカワミクロン社製ＡＦＧ・ＴＪＭなどのなどのジェットミル；、ホソカワミクロン社製ハンマーミル・ファッツミル・フェザーミル・イノマイザー・ＡＣＭパルペライザー、ターボ工業社製ターボミル、川崎重工業社製ＫＴＭ、日清エンジニアリング社製スーパーローター、ＮＰＫ社製ファインミルなどの衝撃式粉砕機などを使用して段階的に所定トナー粒度まで粉砕する。
【００５３】
(4) 微粉砕物を分級機で分級する。分級機としては、アルピネ／ホソカワミクロン社製ＴＳＰ、日清エンジニアリング社製ターボクシファイア、コンダックス／三井鉱山社製ＣＦＳ−ＨＤ、ドナルドソン社製ドナセレックス等の機内に回転ローターを有する気流式分級機、ＮＰＫ社製ＤＳ型・ＤＳＸ型分級機、日鉄鉱業社製エルボジェット分級機、ホソカワミクロン社製ミクロンセパレーターなどを使用して段階的に所定トナー粒度まで分級する。分級工程で発生した粗粉は粉砕工程、又は１段目の分級工程にもどして再利用してもよい。また、トナー微粉は原料混合工程、混練工程に戻して再利用してもよい。
(5) 更に外添処理する場合には、分級物と公知の各種外添剤を所定量配合して、ヘンシェルミキサー、スーパーミキサーなどの粉体にせん断力を与える高速攪拌機などで攪拌・混合する。
【００５４】
(6) 異物および粗大粒子除去の為、ジャイロシフター、佐藤式振動篩、超音波式篩などの振動篩、ターボスクリーナーなどの回転式篩を用いて篩別を行った後、最終トナーを得ることができる。
また、上記の製造法とは全く異なる方法として、例えば、懸濁重合法、乳化重合法による製造、いわゆる重合トナー法によってトナー粒子を形成させてもよい。
得られたトナーの軟化温度が８０〜１６０℃、及びガラス転移温度が５０〜７５℃の範囲が好ましい。軟化温度が８０℃未満ではホットオフセット性が悪化し、機械的強度が弱くなり好ましくなく、一方１６０℃を超えると定着性が悪化し好ましくない。ガラス転移温度が５０℃未満ではトナー凝集や固着を生じ易く、一方７５℃を超えると定着強度が低下し好ましくない。
【００５５】
本発明においては、フルカラー３原色トナーの軟化温度（Ｔｃ、Ｔｍ、Ｔｙ）が８０〜１６０℃で、且つ、黒色トナーの軟化温度（Ｔｂ）が８０〜１６０℃であり、並びにＴｃ、Ｔｍ、ＴｙがＴｂより低く、好ましくは、３℃以上差があるのがより好適であり、更には、３℃以上〜３０℃以下の差が好適である。黒トナーの軟化温度の方が低い場合は高光沢のカラー画像と低光沢の黒色画像が得られなくなり好ましくない。
【００５６】
トナーの軟化温度は、フローテスター（ＣＦＴ−５００、島津製作所製）を用いて約１ｇの試料を昇温速度６℃／ｍｉｎ．で加熱しながら、面積１ｃｍ² のプランジャーにより２０ｋｇ／ｃｍ² の荷重を与え、孔径１ｍｍ、高さ１ｍｍのダイから押し出し、プランジャーの降下開始温度と降下終了温度の中間点に対応する温度を軟化温度としたものである。
また、トナーのガラス転移温度（以下、Ｔｇと云う）は、示差走査熱量計（ＤＳＣ）を用い、昇温速度１０℃／ｍｉｎで１００℃以上に一度昇温した後、ファンによる空冷で室温まで冷却し、再度、昇温した時の変曲点（ショルダー）に接線を引いた交点に対応する温度としたものである。
【００５７】
本発明のトナーが、優れた効果を発揮する理由は必ずしも明確ではないが、以下のように考えている。まず、カラートナーは複数色の混合によって色彩を出すこと及びＯＨＰ投影時の透過性を確保することがあるために透明性が要求され、従って、比較的軟化温度が低いトナーとすることが有利である。一方黒色は、単色で黒色を出すため透明性が要求されず、むしろ低光沢の黒色を出すために比較的軟化温度が高いトナーとすることが有利である。そして、軟化温度が高い黒色トナーワックスにおいては、ポリプロピレンワックスの分子量が比較的高く、融点が比較的高い場合に、混練時にシェアがかかりやすく、カーボンブラック、帯電制御剤などの分散が良くなって均質な組成になりやすく、その為逆極性が少なく感光体上かぶりや白地かぶりが少なくなるものと考えられる。
すなわち、本発明の構成は、フルカラー画像を形成する上で、カラートナーと黒色トナーに要求される性能をバランスして満足しているものということができる。
【００５８】
本発明フルカラー画像形成方法に用いるトナーは、トナーと磁性キャリアを混合して成る２成分系現像剤として用いてもよく、また磁性キャリアを使用しない１成分系トナーとして用いてもよいが、特に、好適には１成分系トナーで用いるのが好ましく、より好適には非磁性１成分系トナーに用いるのが好ましい。
本発明のフルカラー画像形成方法は、接触または非接触の非磁性一成分現像方式により現像し、次いで熱ヒーターを内蔵した定着ロールにトナーを接触させて定着する熱定着方式により画像を形成する電子写真記録装置に使用する場合に、特に有効である。即ち、複数色のカラートナーを定着ロールで一度に定着する場合があるため、カラートナーの軟化温度を低めに設定することが一層要求されるが、本発明の構成によれば十分な定着強度を有し、低温・高温側のオフセット現象がなく、熱ロールに記録紙が巻き付く現象もないなど有用な定着効果を発揮するものである。
特に、タンデム方式のフルカラー画像形成方法では、中間転写方式、多重転写方式などに比し、印字速度を早くすることができる特徴がある。その為、タンデム方式に用いられるのトナーとして、帯電立ち上がり性が早く適切な帯電量が確保でき、感光体へのトナーかぶりが少なく、ベタ画像の均質性が良く、トナー消費量が悪化しないトナーが望まれているが、必ずしも十分なものではなかった。そこで、本発明のトナーをタンデム方式で使用することで上記の課題は解決することができる。
【００５９】
以下に本発明のフルカラー画像形成方法の一例である非磁性１成分系トナーを使用する電子写真記録装置について説明するが、この一例に限定されるものではない。図１は電子写真記録装置の要部構成の概略図であり、感光体１、帯電装置２、露光装置３、現像装置４、転写装置５、クリーニング装置６、及び定着装置７を有している。
感光体１は、例えばアルミニウムなどの導電体により形成され、外周面に感光導電材料を塗布して感光層を形成したものである。感光体１の外周面に沿って帯電装置２、露光装置３、現像装置４、転写装置５及び、クリーニング装置６がそれぞれ配置されている。
【００６０】
帯電装置２は、例えば周知のスコロトロン帯電器、ローラー帯電器などよりなり、感光体１の表面を所定電位に均一帯電する。 露光装置３は、感光体１の感光面にＬＥＤ、レーザー光などで露光を行って感光体１の感光面に静電潜像を形成するものである。
現像装置４は、アジテータ４２、供給ローラー４３、現像ローラー４４、規制部材４５からなり、その内部にトナーＴを貯留している。また、必要に応じ、現像装置にはトナーを補給する補給装置４１を付帯させてもよく、補給装置にはボトル、カートリッジなどの容器からトナーを補給することができるものである。
【００６１】
供給ローラー４３は導電性スポンジ等からなるもので、現像ローラー４４に当接している。現像ローラー４４は、感光体１と供給ローラー４３との間に配置されている。現像ローラー４４は、感光体１及び供給ローラー４３に各々当接している。供給ローラー４３及び現像ローラー４４は、回転駆動機構によって回転される。供給ローラー４３は、貯留されているトナーを担持して現像ローラー４４に供給する。現像ローラー４４は、供給ローラー４３によって供給されるトナーを担持して感光体１の表面に接触させる。
現像ローラー４４は、鉄、ステンレス鋼、アルミニウム、ニッケルなどの金属ロール、又は金属ロールにシリコン樹脂、ウレタン樹脂、フッ素樹脂などを被覆した樹脂ロールなどからなる。現像ロール表面は、必要に応じ平滑加工したり、粗面加工したりしてもよい。
【００６２】
規制部材４５は、シリコーン樹脂やウレタン樹脂などの樹脂ブレード、ステンレス鋼、アルミニウム、銅、真鍮、リン青銅などの金属ブレード、金属ブレードに樹脂を被覆したブレード等により形成されている。この規制部材４５は、現像ローラー４４に当接し、ばね等によって現像ローラー４４側に所定の力で押圧（一般的なブレード線圧は５〜５００ｇ／ｃｍ）されており、必要に応じトナーとの摩擦帯電によりトナーに帯電を付与する機能を具備させてもよい。
アジテーター４２は、回転駆動機構によってそれぞれ回転されており、トナーを攪拌するとともに、トナーを供給ローラー４３側に搬送する。アジテータは、羽根形状、大きさ等を違えて複数設けてもよい。
転写装置５は、感光体１に対向して配置された転写チャージャー、転写ローラー、転写ベルトなどよりなる。この転写装置５は、トナーの帯電電位とは逆極性で所定電圧値（転写電圧）を印加し、感光体１に形成されたトナー像を記録紙Ｐに転写するものである。
【００６３】
クリーニング装置６は、ウレタン等のブレード、ファーブラシなどのクリーニング部材からなり、感光体１に付着している残留トナーをクリーニング部材で掻き落とし、残留トナーを回収するものである。
定着装置７は、上部定着部材７１と下部定着部材７２とからなり、上部又は下部の定着部材の内部には加熱装置７３を有している。定着部材はステンレス、アルミニウムなどの金属素管にシリコンゴムを被覆した定着ロール、更にテフロン樹脂で被覆した定着ロール、定着シートなどが公知の熱定着部材を使用することができる。更に、定着部材には離型性を向上させる為にシリコンオイル等の離型剤を供給してもよい。また、上部定着部材と下部定着部材にはバネ等により強制的に圧力を加わえる機構としてもよい。
用紙Ｐ上に転写されたトナーは、所定温度に加熱された上部定着部材７１と下部定着部材７２の間を通過する際、トナーが溶融状態まで熱加熱され、通過後冷却されて記録紙Ｐ上にトナーが定着される。
【００６４】
以上のように構成された電子写真現像装置では、次のようにして画像の記録が行われる。即ち、まず感光体１の表面（感光面）は、帯電装置２によって所定の電位（例えば−６００Ｖ）に帯電される。続いて、帯電されたのちの感光体１の感光面を記録すべき画像に応じて露光装置３によって露光し、感光面に静電潜像を形成する。そして、その感光体１の感光面に形成された静電潜像の現像を現像装置４で行う。
現像装置４は、供給ローラー４３により供給されるトナーを現像ブレード４５により薄層化されるとともに、所定の極性（ここでは感光体１の帯電電位と同極性であり、負極性）に摩擦帯電されて、現像ローラー４４に担持し、搬送して感光体１の表面に接触させる。
【００６５】
現像ローラー４４からいわゆる反転現像法により感光体１の表面に静電潜像に対応するトナー像が形成される。そしてこのトナー像は、転写装置５によって用紙Ｐに転写される。この後、感光体１の感光面は転写されずに残留しているトナーがクリーニング装置６で除去される。
記録紙Ｐ上の転写後トナーは定着装置７を通過させて熱定着することで、最終的な画像が得られる。
【００６６】
次に、非磁性１成分系トナーをフルカラーとして使用するタンデム方式電子写真記録装置の一例について説明する。図２はフルカラータンデム方式の主要構成の概略図であり、感光体１、帯電装置２、露光装置３、ブラック現像装置４k 、シアン現像装置４c 、イエロー現像装置４y 、マゼンタ現像装置４m 、転写装置５、及び定着装置７を有し、ここではクリーニング装置は省略した。カラー画像はマゼンタ、イエロー、シアン、及びブラックの各トナーを多層に重ねて所望する色に調整することでカラー画像を得ることができる。タンデム方式の場合、カラー現像部がブラック現像部より前に位置する方がブラックトナーの逆転写などによる混色が少なくなりよいこと、及びブラック現像部がカラー現像部より後ろに位置する方がブラックだけの単色で画像形成する場合にカラートナーの感光体カブリによる混色が少なくなること、及びカラー現像部をショートパスして記録紙を搬送することでブラック画像形成の速度アップすることができるので好ましい。本発明のトナーは、この様なシアン、マゼンタ、イエローのカラー現像部が前の位置にあり、ブラック現像部がカラー現像部より後に位置するタンデム方式に好適である。なお、シアン、マゼンタ、イエローのカラー現像部の位置する順番は適時自由に変更することができる。
【００６７】
【実施例】
以下、実施例により本発明を更に詳細に説明するが、本発明はその要旨を超えない限り下記の実施例により限定されるものではない。なお、各実施例および比較例中、単に「部」とあるのはいずれも「重量部」を表すものとする。
【００６８】
【表１】
[ 実施例１]
＜ブラックトナーＫ１の作製＞
・非線形ポリエステル樹脂Ａ１ １００部
Ｓｐ：１５０℃、 Ｔｇ：６５℃
ＴＨＦ不溶分：２０％
酸価：８ＫＯＨｍｇ／ｇ、
水酸基価：３０ＫＯＨｍｇ／ｇ
Ｍｎ：２，４００、 Ｍｗ：８７, ０００
・ポリプロピレンワックスｐ ２部
［Ｍｎ：３，０００、融点：１４４℃、密度：０．８９ｋｇ／ｍ³ 、
酸価：０ＫＯＨｍｇ／ｇ］
・ポリエチレンワックスｂ １部
［Ｍｎ：３，０００、融点：１２９℃、密度：０．９５ｋｇ／ｍ³ ］
・カーボンブラック 三菱化学社製 ＭＡ−７７ ４．５部
・帯電制御剤 保土谷化学工業社製 Ｔ−７７ １部
【００６９】
上記組成を高速攪拌機で予混合し、２軸の連続押出機で混練した後、２本ロールで圧延しながら速やかに冷却する。冷却物はフェザーミルで２ｍｍ目をパスするまで粗粉し、次いでジェット式粉砕機・気流式分級機にて体積平均粒子径８．７μｍ程度に調整し、分級トナーを得た。このトナーの軟化温度（Ｔｂ）は１４０℃、Ｔｇは６５℃であった。
次いで、分級トナー１００部と日本アエロジル社製ＲＹ５０シリカ１．８部をヘンシェルミキサーで混合し、更にキャボット社製ＴＧ−３０８Ｆシリカ０．２部を加えて追加混合し、ブラックトナーＫ１を調整した。
【００７０】
【表２】
＜シアントナーＣ１の作製＞
・非線形ポリエステル樹脂Ａ２ １００部
Ｓｐ：１３５℃、 Ｔｇ：６３℃
ＴＨＦ不溶分：１０％
酸価：５ＫＯＨｍｇ／ｇ、
水酸基価：３３ＫＯＨｍｇ／ｇ
Ｍｎ：７，２００、 Ｍｗ：８１, ０００
・ポリプロピレンワックスｑ ２部
［Ｍｎ：３，０００、融点：１３２℃、密度：０．８９ｋｇ／ｍ³ 、
酸価：０ＫＯＨｍｇ／ｇ］
・シアン色マスターバッチ顔料 １０部
予め、シアン顔料Ｃ．Ｉ．ピグメント・ブルー１５：３を
４０部とポリエステル樹脂Ｂ１を６０部でマスターバッチ
処理を施したもの
但し、ポリエステル樹脂Ｂ１は次のものである。
Ｓｐ：１１０℃、Ｔｇ：６５℃
酸価：７ＫＯＨｍｇ／ｇ
水酸基価：３０ＫＯＨｍｇ／ｇ
Ｍｎ：４，４００ Ｍｗ：４５，０００
・帯電制御剤 日本カーリット社製 ＬＲ−１４７ １部
【００７１】
ブラックＫ１の配合処方を上記とした以外はブラックＫ１と同じ操作で分級トナーを作製し、次いで、分級トナー１００部と日本アエロジル社製ＲＹ５０シリカ１．８部をヘンシェルミキサーで混合し、更に日本アエロジル社製Ｒ８１２シリカ０．２部を加えて追加混合し、シアントナーＣ１を調整した。このトナーの軟化温度（Ｔｃ）は１２５℃、Ｔｇは６４℃であった。
【００７２】
【表３】
＜マゼンタトナーＭ１の作製＞
・マゼンタ色マスターバッチ顔料 １０部
予め、マゼンタ顔料Ｃ．Ｉ．ピグメント・レッド５７：１を
４０部とポリエステル樹脂Ｂ１を６０部でマスターバッチ
処理を施したもの
【００７３】
シアンＣ１のマスターバッチ顔料をシアン色から上記のマゼンタ色とした以外はシアンＣ１と同じ操作でマゼンタトナーＭ１を調整した。このトナーの軟化温度（Ｔｍ）は１２７℃、Ｔｇは６４℃であった。
【００７４】
【表４】
＜イエロートナーＹ１の作製＞
・イエロー色マスターバッチ顔料 １０部
予め、イエロー顔料Ｃ．Ｉ．ピグメント・イエロー１７を
４０部とポリエステル樹脂Ｂ１を６０部でマスターバッチ
処理を施したもの
【００７５】
シアンＣ１のマスターバッチ顔料をシアン色から上記のイエロー色とした以外はシアンＣ１と同じ操作でイエロートナーＹ１を調整した。このトナーの軟化温度（Ｔｙ）は１２５℃、Ｔｇは６３℃であった。
これらＫ１、Ｃ１、Ｍ１、Ｙ１のトナーを用いて市販のタンデム機構のフルカラープリンタＡ（Ａ４普通紙のカラー速度１２枚／分；３原色・黒色トナー共に非磁性１成分接触現像方式；現像部の順番はマゼンタ、シアン、イエロー、ブラックの順；感光体が有機光導電体；熱ロール定着方式で普通紙の定着温度が１９０℃）で画像特性を評価した結果を表１に、ブラックＫ１と３原色トナーの内シアンＣ１を用いて外部定着機でのオフセット性を評価した結果を表にそれぞれ示すが全てにおいて優れており、良好であった。
【００７６】
【表５】

【００７７】
【表６】

【００７８】
【表７】
[ 実施例２]
＜ブラックトナーＫ２の作製＞
・ポリプロピレンワックス（酸化型）ｒ ２部
［Ｍｎ：３，０００、融点：１４５℃、密度：０．８９ｋｇ／ｍ³ 、
酸価：３．５ＫＯＨｍｇ／ｇ］
【００７９】
実施例１のブラックトナーＫ１のポリプロピレンワックスｐを上記のポリプロピレンワックスｒに変更した以外はＫ１と同様な操作でブラックトナーＫ２を作製した。このトナーの軟化温度（Ｔｂ）は１４１℃、Ｔｇが６４℃であった。
このブラックトナーＫ２の定着性は良好であり、３原色トナーＣ１，Ｍ１，Ｙ１と一緒に用いてフルカラープリンタＡで画像特性を評価したが、全てにおいて優れており、良好であった。
【００８０】
【表８】
[ 実施例３]
＜ブラックトナーＫ３の作製＞
・ポリプロピレンワックスｓ ２部
［Ｍｎ：４，０００、融点：１４７℃、密度：０．８９ｋｇ／ｍ³ 、
酸価：０ＫＯＨｍｇ／ｇ］
【００８１】
実施例１のブラックトナーＫ１のポリプロピレンワックスｐを上記のポリプロピレンワックスｓに変更した以外はＫ１と同様な操作でブラックトナーＫ３を作製した。このトナーの軟化温度（Ｔｂ）は１４０℃、Ｔｇが６４℃であった。
このブラックトナーＫ３の定着性は良好であり、３原色トナーＣ１，Ｍ１，Ｙ１と一緒に用いてフルカラープリンタＡで画像特性を評価したが、全てにおいて優れており、良好であった。
【００８２】
【表９】
[ 比較例１]
＜ブラックトナーＫ４の作製＞
実施例１のブラックトナーＫ１のポリプロピレンワックスｐを無し（添加部数０）とした以外はトナーＫ１と同様な操作でブラックトナーＫ４を作製した。このトナーの軟化温度（Ｔｂ）が１４１℃、Ｔｇが６５℃であった。このブラックトナーＫ４と実施例１の３原色トナーＣ１，Ｍ１，Ｙ１を用いてフルカラープリンタＡで画像特性を評価した結果、感光体上かぶり、白地かぶりが悪であり、また、外部定着機での低温側オフセット発生温度が１４０℃と高めで好ましくなかった。
【００８３】
【表１０】
[ 比較例２]
＜ブラックトナーＫ５の作製＞
・ポリプロピレンワックスｑ ２部
［Ｍｎ：３，０００、融点：１３２℃、密度：０．８９ｋｇ／ｍ³ 、
酸価：０ＫＯＨｍｇ／ｇ］
【００８４】
実施例１のブラックトナーＫ１のポリプロピレンワックスｐを上記のポリプロピレンワックスｑに変更した以外はＫ１と同様な操作でブラックトナーＫ５を作製した。このトナーの軟化温度（Ｔｂ）は１４０℃、Ｔｇが６４℃であった。
このブラックトナーＫ５と実施例１の３原色トナーＣ１，Ｍ１，Ｙ１と一緒に用いてフルカラープリンタＡで画像特性を評価した結果、感光体上かぶりが著しく悪く、白地かぶりも悪く、好ましくなかった。
【００８５】
【表１１】
[ 比較例３]
＜シアンＣ２，マゼンタＭ２，イエローＹ２トナーの作製＞
・ポリプロピレンワックスｔ ２部
［Ｍｎ：４，０００、融点：１４７℃、密度：０．８９ｋｇ／ｍ³ 、
酸価：０ＫＯＨｍｇ／ｇ］
【００８６】
実施例１の３原色トナーのシアンＣ１、マゼンタＭ１、イエローＹ１のポリプロピレンワックスｑを上記ポリプロピレンｔに変更した以外はそれぞれの対応色と同じ操作でシアンＣ２、マゼンタＭ２、イエローＹ２を作製した。これらトナーの軟化温度／Ｔｇは、Ｃ２が１２５℃／６４℃、Ｍ２が１２７℃／６４℃、Ｙ２が１２６℃／６４℃であった。３原色トナーの内シアンＣ２を用いて外部定着機での評価した結果、高温側オフセット発生温度が２１０℃と低く、また、これら３原色トナーＣ２，Ｍ２，Ｙ２と実施例１のブラックトナーＫ１を用いてフルカラープリンタＡで画像特性を評価した結果、３原色トナーの画像濃度が低くなり、好ましくなかった。
【００８７】
【表１２】
[ 実施例４]
・帯電制御剤 オリエント化学工業社製 Ｓ−３４ １部
【００８８】
実施例１の帯電制御剤をＴ−７７に代えて上記のＳ−３４とした以外は実施例１と同じ操作でブラックトナーＫ６を調整した。このトナーの軟化温度（Ｔｍ）１４０℃、Ｔｇ６４℃であった。
このトナーＫ６の定着性は良好であり、３原色トナーＣ１，Ｍ１，Ｙ１と一緒に用いてフルカラープリンタＡで画像特性を評価した結果、感光体上かぶりが２．０とやや高めであった以外はほぼ良好であった。
【００８９】
［評価方法］ 各評価項目の試験方法は次の通りとした。
１．画像濃度
所定のフルカラープリンタで普通紙を用いてプリントした画像部を日本平版機材社製分光測色濃度計Ｘ−Ｒｉｔｅ９３８（光源：Ｄ65光源、視野角度２゜、レスポンス：Ｔ）で反射濃度を測定し、画像濃度とした。
２．白地かぶり
所定のフルカラープリンタで普通紙を用いてプリントし、非画像部である白地部を日本電色工業社製色差計Ｚ−Σ８０でＸＹＺを測定し、プリント前後の白地部Ｚ値から次式により白地かぶりを求めた。
【００９０】
【数３】
白地かぶり（ΔＺ_w ）＝Ｚ_p −Ｚ_i
Ｚ_i ：プリント前の白地部Ｚ値
Ｚ_p ：プリント後の白地部Ｚ値
【００９１】
３．感光体上かぶり
所定フルカラープリンタのトナーを入れて普通紙を用いて白紙モードでプリントし、プリント途中で強制的に停止させ、感光体上のかぶり（感光体上の現像部より後で転写部より前の位置するトナー）を３Ｍ社製メンディングテープで採取し、採取後に普通紙（白紙）に貼り付ける。貼り付けたテープのかぶり部を日本平版機材社製分光測色濃度計Ｘ−Ｒｉｔｅ９３８（光源：Ｄ65光源、視野角度２゜、レスポンス：Ｔ）でＬ^* ａ^* ｂ^* を測定し、かぶり採取前後のＬ^* ａ^* ｂ^* から次式により色差（△Ｅ₂ ）を求め、白地かぶりとした。
【００９２】
【数４】
色差（△Ｅ₂ ）＝［（Ｌ^* _j −Ｌ^* _q ）² ＋（ａ^* _j −ａ^* _q ）² ＋（ｂ^* _j −ｂ^* _q ）² ］^1/2
Ｌ^* _j 、ａ^* _j 、ｂ^* _j ：かぶり採取前のテープ値
Ｌ^* _q 、ａ^* _q 、ｂ^* _q ：かぶり採取後のテープ値
【００９３】
４．光沢度
所定のフルカラープリンタでベタ画像を普通紙にプリントし、日本電色工業社製光沢度計ＶＧ−２０００（角度７５°）で測定したグロス値を光沢度とした。
５．外部定着でのオフセット性
予めフルカラープリンタＡで四角いベタ画像を未定着の状態（以下、未定着画像と云う）で採取する。
次いで、テフロンで最上層が被覆された直径２５ｍｍの上部定着ローラ（内部に温度制御可能なヒータを内蔵する）とシリコンゴムで最上層が被覆された直径１８ｍｍの下部定着ローラより構成された外部定着機でもって、上部定着ローラの表面温度を放射温度計で測定しながら５℃キザミで温度を変化させる。この際、上部と下部の定着ローラニップ幅は３ｍｍ程度とし、シリコンオイル等の離型剤の供給は無しとする。なお、普通紙を用いた場合の通過速度は５６ｍｍ／ｓｅｃとした。
各温度に対して未定着画像を通過させ定着画像を得、オフセットの発生状態から低温側オフセット及び高温側オフセットが発生する温度を測定した。
【００９４】
【発明の効果】
本発明によれば、電子写真記録装置などで用いるフルカラー画像形成方法において、トナー帯電特性が良好で、画像濃度、かぶりなどの画像特性が良く、連続印字した場合でも耐久特性が安定して良好であり、熱定着での定着性も良好であり優れた効果を奏するものである。
【図面の簡単な説明】
【図１】本発明のフルカラー画像形成方法の一例である非磁性１成分系トナー使用する電子写真記録装置の要部構成の概略図を示すものである。
【図２】本発明のフルカラー画像形成方法の一例であるフルカラータンデム方式で使用する電子写真記録装置の主要構成の概略図を示すものである。
【符号の説明】
１ 感光体
２ 帯電装置
３ 露光装置
４ 現像装置
５ 転写装置
６ クリーニング装置
７ 定着装置
４k ブラック現像装置
４y イエロー現像装置
４c シアン現像装置
４m マゼンタ現像装置
４１ 補給装置
４２ アジテータ
４３ 供給ローラ
４４ 現像ローラ
４５ 規制部材
７１ 上部定着部材
７２ 下部定着部材
７３ 加熱装置
Ｔ トナー
Ｐ 記録紙[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming method for forming an electrostatic charge image in electrophotography, electrostatic charge recording, electrostatic printing, and the like, and in particular, forms a color image using three primary color toners of cyan, magenta and yellow and a black toner. The present invention relates to a full color image forming method.
[0002]
[Prior art]
Conventionally, as described in the specifications of U.S. Pat. Nos. 2,217,762, 2,297,691, and 2,357,809 as electrophotographic methods, the photoconductive insulating layer is uniformly charged (charging step), and then The layer is exposed (exposure process), an electrostatic latent image is formed by dissipating the charge of the exposed portion, and a colored charged fine powder called toner is added to the electrostatic latent image. It is visualized by adhering (development process), and the obtained visible image is transferred onto a transfer material such as transfer paper (transfer process), and then permanently fixed by heating, pressure or other suitable means (fixing) Process). After the toner image is transferred, the residual toner on the photoconductor is scraped to clean the surface of the photoconductor (cleaning step). Further, as described in U.S. Pat. No. 2,962,374, as a full-color electrophotographic method for obtaining a color multicolor image, at least an image is decomposed into color signals of three primary colors of cyan, magenta, and yellow and exposed. The above process is repeated at least several times using process colors such as cyan, magenta, and yellow to obtain a multicolor image in which toner images are superimposed.
[0003]
In recent years, optical information processing such as masking processing and UCR processing (under color removal), which has been difficult in the conventional analog system, can be easily performed by adopting a digital system. Conventionally, a portion expressing black by overlapping toners of three primary colors of cyan, magenta, and yellow can be replaced with black toner alone, so that the gray balance of the image is improved and the thickness of the toner layer is reduced. This is advantageous in terms of cost and image curl development at the time of fixing. Therefore, as a recent full-color toner, a four-color toner obtained by adding a black toner to a toner of three primary colors of cyan, magenta, and yellow is used, but other color toners may be added as necessary. .
[0004]
As a method for forming a full-color image using an electrophotographic method, various known methods can be used. For example, a toner image formed on a photoreceptor is wound on a recording sheet wound around a transfer drum for each color. Transfer drum system that transfers and superimposes four colors on recording paper, intermediate transfer system that superimposes four color toner images on an intermediate transfer body such as a belt or drum, and then transfers the four colors onto the recording paper. There are a tandem system that has a photoconductor and a developing device for each color, and sequentially superimposes four colors on the recording paper in one pass, and a multiple transfer system that superimposes the four colors on the photoconductor and then transfers them onto the recording paper.
On the other hand, digital full-color copying machines, printers, and the like are still mainly black and white images for general office use, and black toners having a low gloss on the surface of the image are preferred. In addition, high-quality glossy images are preferred for full-color images such as presentations and photographs, and further, it is desired that images on an overhead projector (hereinafter referred to as OHP) sheet have good light transmittance.
[0005]
In particular, in a miniaturized digital full-color printer that has been actively developed in recent years, the specifications of U.S. Pat. Nos. 2,895,847 and 3,515,2012, Japanese Patent Publication Nos. 41-9475, 45-2877, A non-magnetic one-component developing method described in JP-A No. 54-3624 is used, and a tandem method is attracting attention as a full-color image forming method corresponding to high speed.
As printers become smaller and faster, developing devices, photoconductors, fixing devices, and the like become smaller, and the process speed tends to increase. Therefore, in the developing device, the charging of the toner is reduced, the charge rising property is deteriorated, the toner fog is increased on the photosensitive member, the white background fog of the printed matter is generated, and the toner charge amount is reduced. If the density is too high, toner consumption may be deteriorated. Further, in the fixing device, the fixing member is reduced in size and the sheet passing speed is increased, so that the fixing strength is lowered, and the fixing property is deteriorated, for example, the phenomenon that the paper curls and winds around the fixing roll occurs.
[0006]
For these improvements, it has been proposed in Japanese Patent No. 2841332 etc. that the viscoelasticity of the three primary color toners and the black toner is different, and in Japanese Patent No. 2768181 etc., when forming a monochrome image and when forming a color image. Different fixing heat amounts are proposed, and Japanese Patent Application Laid-Open No. 8-23491 proposes that the softening points of the color toner and the black toner are different. Add polyolefin waxes such as polypropylene and polyethylene to JP-A-49-65231, JP-A-58-16250, JP-A-50-27546, JP-A-55-153944, JP-A-9-73187, etc. Has been proposed, but it was not enough.
[0007]
[Problems to be solved by the invention]
Accordingly, the first object of the present invention is to provide a sufficient charging effect to the toner with a small-sized developing device, and it is possible to secure an appropriate amount of charge by quickly raising the charge, and extra toner fog on the photoreceptor is prevented. It is an object of the present invention to provide a full-color image forming method that has little and no white background stain on the printed matter and good solid image uniformity. A second object is to provide a full-color image forming method that has good durability when continuously printed by a printer or the like, and image characteristics such as image density and fogging and toner consumption are stabilized. The third object is to provide a full-color image forming method with good fixing performance, such as a heat roll such as a heating roll, which has no offset and curling phenomenon and can provide a sufficient fixing strength.
[0008]
[Means for Solving the Problems]
  As a result of intensive studies in view of the above circumstances, the present inventors have solved the problems of conventional full-color image forming methods by making the softening point of color toner and black toner different from the melting point of polyolefin wax, and have excellent characteristics. As a result, the present invention has been completed. That is, the gist of the present invention is to provide a plurality of color toners and black toners in a full-color image forming method for forming a color image using a plurality of color toners and black toners.ConcludeLanding resin,Polypropylene waxA colorant and a charge control agent, the softening temperatures of the plurality of color toners are all lower than the softening temperature of the black toner, and the melting points of the polypropylene wax in the plurality of color toners are all in the black toner. A full-color image forming method characterized by being lower than the melting point of the polypropylene wax.
[0009]
  Another aspect of the present invention is a full color image forming method for forming a color image using a plurality of color toners and black toners, and the plurality of color toners and black toners.ConcludeLanding resin,Polypropylene waxA colorant and a charge control agent, the softening temperatures of the plurality of color toners are all lower than the softening temperature of the black toner, and the number average molecular weight of the polypropylene wax in the plurality of color toners is all black. The present invention resides in a full-color image forming method characterized by being lower than the number average molecular weight of polypropylene wax in the toner.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the full-color image forming method, at least three colors of cyan, magenta, and yellow are used as color toners, but a plurality of color toners of four or more colors can be used by adding other colors. Hereinafter, a case where three color toners of cyan, magenta, and yellow are used will be described.
The toner particles used in the present invention are finely divided powders containing a polyester resin, a colorant, a negative charge control agent, and other additives as required, and the average particle size of the toner particles is 4 to 20 μm. It is preferably 4 to 12 μm. The toner particle size can be measured, for example, with a Coulter counter manufactured by Beckman Coulter, Multisizer, or the like.
[0011]
As the binder resin used in the present invention, various known styrene / acrylic resins, polyester resins, epoxy resins and urethane resins suitable for toners can be used, and linear or nonlinear polyester resins are particularly preferable. Furthermore, it is preferable that the binder resin for the three primary color toners is a linear or nonlinear polyester resin and the binder resin for the black toner is a nonlinear polyester resin, more preferably tetrahydrofuran (hereinafter referred to as THF) of the polyester resin of the three primary colors. It is preferable that the insoluble content is less than that of the black polyester resin. The polyester resin is particularly excellent in terms of both mechanical strength and fixability when used as a non-magnetic one-component toner, and the non-linear one in which the polyester resin for black toner contains a THF-insoluble component has low gloss. It is preferable that the polyester resin for the three primary colors is linear without a THF-insoluble component or a non-linear one containing a small amount of a THF-insoluble component because of high glossiness. Note that linear and non-linear polyester resins may be mixed and used for both the color three primary color toner and the black toner polyester resin, and the toner molecular weight, softening point, and the like are in a suitable range by adjusting the mixing ratio thereof. Can be freely controlled.
[0012]
The polyester resin is composed of a polyhydric alcohol and a polybasic acid, and if necessary, at least one of the polyhydric alcohol and the polybasic acid polymerizes a monomer composition containing a trifunctional or higher polyfunctional component (crosslinking component). Can be obtained. In the above, examples of the divalent alcohol used in the synthesis of the polyester resin include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and neopentyl. Diols such as glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, etc. Bisphenol A alkylene oxide adducts and others can be mentioned. Among these monomers, it is particularly preferable to use a bisphenol A alkylene oxide adduct as the main component monomer, and among them, an adduct having an average addition number of alkylene oxide of 2 to 7 per molecule is preferable.
[0013]
Examples of the trihydric or higher polyhydric alcohol involved in the crosslinking of polyester include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, and sucrose. 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1, Mention may be made of 3,5-trihydroxymethylbenzene and others.
[0014]
On the other hand, polybasic acids include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malon Examples include acids, anhydrides of these acids, lower alkyl esters, or alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid and n-dodecyl succinic acid, and other divalent organic acids.
Examples of the tribasic or higher polybasic acid involved in the crosslinking of polyester include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2, 5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) Mention may be made of methane, 1,2,7,8-octanetetracarboxylic acid, and anhydrides thereof.
[0015]
These polyester resins can be synthesized by a usual method. Specifically, conditions such as reaction temperature (170 to 250 ° C.) and reaction pressure (5 mmHg to normal pressure) are determined according to the reactivity of the monomer, and the reaction may be terminated when predetermined physical properties are obtained. .
In these polyester resins, the softening temperature (Sp) is 80 to 160 ° C, and among them, those having 90 to 150 ° C are more preferable. Moreover, the glass transition temperature (Tg) is 50-75 degreeC, Among these, the thing of 55-70 degreeC is more suitable. In this case, when Sp is lower than the above range, an offset phenomenon at the time of fixing is likely to occur. When Sp is higher than the above range, the fixing energy increases, and color toner tends to deteriorate glossiness and transparency. . Further, when Tg is lower than the above range, toner agglomerates and fixation are likely to occur, and when Tg is higher than the above range, the fixing strength at the time of thermal fixing tends to be low, such being undesirable. Sp can be adjusted mainly by the molecular weight of the resin, and the number average molecular weight is preferably 2,000 to 20,000, more preferably 3,000 to 12,000. Further, Tg can be adjusted mainly by selecting a monomer component constituting the resin. Specifically, Tg can be increased by using an aromatic polybasic acid as a main component as an acid component. That is, among the polybasic acids described above, phthalic acid, isophthalic acid, terephthalic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid and the like, and anhydrides thereof, lower alkyl esters, etc. It is desirable to use it as a main component.
[0016]
The THF-insoluble content (%) of the polyester resin is determined using a Soxhlet extractor.₁ ) Was removed by extraction with THF for 6 hours, and then the remaining amount without extraction was weighed (W₂ ) To obtain the formula (W₂ / W₁ ) × 100 (%).
Sp of the polyester resin was measured using a flow tester described in JIS K7210 and K6719. Using a flow tester (CFT-500, manufactured by Shimadzu Corporation), a sample of about 1 g was heated at a rate of temperature increase of 3 ° C./min. 1cm area while heating with² 30kg / cm with a plunger² The temperature corresponding to the midpoint between the descending start temperature and the descending end temperature of the plunger is set as the softening temperature by extruding from a die having a hole diameter of 1 mm and a height of 10 mm.
In addition, Tg is measured using a differential scanning calorimeter (DSC) at a temperature rising rate of 10 ° C./min, and a temperature corresponding to an intersection obtained by drawing a tangent to the inflection point (shoulder).
[0017]
On the other hand, in general, when the acid value of the polyester resin is too high, it is difficult to obtain a stable high charge amount, and the charge stability at high temperature and high humidity tends to deteriorate. Therefore, in the present invention, the acid value is set to 30 KOHmg. / G or less, more preferably 25 KOH mg / g or less. As a method for adjusting the acid value within the above-mentioned range, in addition to a method of controlling the addition ratio of alcohol-based and acid-based monomers used at the time of resin synthesis, for example, the acid monomer component is previously converted into a lower alkyl ester by transesterification. Examples include a method of synthesizing using an acid group and a method of neutralizing residual acid groups by adding a basic component such as an amino group-containing glycol to the composition. It goes without saying that can be adopted. The acid value and hydroxyl value of the polyester resin are measured according to the method of JIS K0070. However, if the resin is difficult to dissolve in the solvent, a good solvent such as dioxane may be used.
[0018]
These polyester resins can be used alone or in combination of two or more kinds of resins having different components from known polyester resins, or different resins having different viscoelastic properties and thermal properties such as different molecular weight distribution even with the same kind of resins. You may use together and use a seed | species or more. Further, known resins such as styrene resins other than polyester resins, styrene / acrylic copolymer resins, epoxy resins, and urethane resins may be used in combination, but the total amount of the polyester resin is 50% by weight or more. preferable.
[0019]
Next, the polypropylene wax used in the present invention will be described.
In this specification, polypropylene wax includes not only pure polypropylene but also what is commonly called polypropylene wax and is commercially available, such as ethylene-propylene copolymer, copolymer of propylene and other olefins. Including coalescence, oxidation type, and modification type. In this case, the proportion of the propylene monomer unit in the polypropylene wax is usually 50% or more, preferably 70% or more, and more preferably 80% or more.
Moreover, in this invention, other polyolefin wax can be used together besides a polypropylene wax.
[0020]
Examples of polyolefin waxes other than polypropylene used in the present invention include polypropylene, polyethylene, polybutene, polyhexene, and ethylene-butene copolymer.
The melting point of these polypropylenes and other polyolefin waxes used in the present invention is preferably 70 to 180 ° C, more preferably 80 to 160 ° C. At a high melting point exceeding 180 ° C., the polyolefin is not sufficiently melted even when heated in a toner kneader or the like, and the compatibility and dispersibility in the resin tend to deteriorate, and the minimum fixing temperature of the toner is low. It tends to get worse. Further, when the melting point is lower than 70 ° C., the toner is less likely to be sheared when manufactured with a toner kneader or the like, and the dispersibility of the colorant and other internal additives tends to deteriorate.
As the polypropylene wax, those having a melting point of 90 to 160 ° C. are particularly preferable.
[0021]
In the present invention, when the polypropylene wax and other polyolefin wax are used in combination, the polypropylene wax is preferably 50% by weight or more, more preferably 65% or more, based on the whole wax.
The polyolefin wax used in combination with the polypropylene wax is particularly preferably a polyethylene wax having a melting point of 80 to 160 ° C.
The number average molecular weight (Mn) of the polypropylene wax is preferably 1,000 to 10,000, and more preferably 2,000 to 10,000. Moreover, when the polyolefin wax used together is a polyethylene wax, the number average molecular weight is preferably 1,000 to 7,000. If Mn is significantly lower than the above range, filming phenomenon on the photosensitive member or developing member tends to occur easily. If Mn is extremely high, the one-component charging characteristic is inferior, and fogging on the photosensitive member or white paper stains on plain paper There is a tendency that the improvement effect is hardly exhibited.
[0022]
The molecular weight of the polyolefin wax is measured by a high-temperature gel permeation chromatograph method (hereinafter referred to as GPC). Although there are some differences depending on the measurement conditions, it can be measured, for example, under the following conditions. That is, at a temperature of 135 ° C., O-dichlorobenzene (with 0.1% ionomer added) is used as a solvent, and flowed at a flow rate of 1 ml per minute, and 400 μl of a 0.1 wt% concentration sample solution is injected and measured. In measuring the molecular weight of the sample, a polystyrene equivalent value is used from a calibration curve prepared using a monodisperse polystyrene standard sample. In addition, although the column to be used is not limited at all, for example, there is A-80M manufactured by Shodex.
[0023]
The melting point of the polyolefin wax is determined from the endothermic pattern of thermal analysis (differential thermal analyzer, differential scanning calorimeter, etc.), and the peak position temperature is taken as the melting point.
The added amount of the polyolefin wax is preferably 0.1 to 6 parts by weight, more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the binder resin. If the addition amount is less than 0.1 parts by weight, the fog on the photoreceptor and the white background stain of the plain paper are deteriorated, and if it exceeds 6 parts by weight, filming phenomenon on the photoreceptor and the developing member tends to occur. It is not preferable because poor transportability due to poor fluidity is likely to occur.
[0024]
In the toner used in the present invention, the melting point (MPc) of the polypropylene wax contained in the cyan toner and the magenta toner included in the polypropylene wax contained in the cyan, magenta and yellow primary toners and the polypropylene wax contained in the black toner. The melting point (MPm) of polypropylene wax and the melting point (MPy) of polypropylene wax contained in yellow toner are both lower than the melting point (MPb) of polypropylene wax contained in black toner, or cyan. Number average molecular weight (Mnc) of polypropylene wax contained in toner, number average molecular weight (Mnm) of polypropylene wax contained in magenta toner, and number average molecular weight of polypropylene wax contained in yellow toner ( Any of ny) is the number average molecular weight of polypropylene wax included in the black toner (that or those less than Mnb) is a requirement.
[0025]
As the colorant used in the black toner of the present invention, various known dyes and pigments such as carbon black, magnetite, and aniline black can be used, but when used in a non-magnetic toner, carbon black is good, Magnetite is preferred for use with magnetic toners. In particular, when used in a non-magnetic one-component negatively charged toner, acidic carbon black is preferable, and the acidity is 6 when the pH of the suspension after boiling carbon black and pure water is measured. The following are mentioned, More preferably, 5 or less is suitable. Other than acidic carbon black, the negative chargeability is not improved, which is not preferable. The carbon black of the present invention is preferably produced by a furnace method. Specific surface area of carbon black by nitrogen adsorption by BET method is 20-500m² It is preferable that the oil absorption of dibutyl phthalate (DBP) is about 30 to 150 ml / 100 g / g. BET specific surface area is 20m² If the particle size is less than / g, the particles become too large and the dispersibility of the carbon black deteriorates.² If it is higher than / g, the particles are finely kneaded and are less likely to be sheared, resulting in poor dispersion of carbon black.
[0026]
Further, for the purpose of surface modification, the curve black may be subjected to a surface treatment with a metal soap or the like as necessary, or an untreated one and a surface treated one may be used in combination.
Various known dyes and pigments can be used as the colorant for the three primary colors (cyan, magenta, yellow) of the present invention, and the following are listed as examples. Examples of yellow toner include C.I. I. Acetoacetic acid arylamide monoazo yellow pigments such as CI Pigment Yellow 1, 3, 74, 97, 98; I. C.I. Pigment Yellow 12, 13, 13, 17, etc. acetoacetic acid arylamide disazo yellow pigments; I. Condensed monoazo yellow pigments such as CI Pigment Yellow 93 and 155; I. Other yellow pigments such as C.I. Pigment Yellow 180, 150 and 185; I. Solvent Yellow 19, 77, 79, C.I. I. Examples include yellow dyes such as Disperse Yellow 164. Examples of magenta toner include C.I. I. Pigment Red 48, 49: 1, 53: 1, 57, 57: 1, 81, 122, 5, 146, 184, 238; I. Red or red pigments such as CI Pigment Violet 19; I. Examples thereof include red dyes such as Solvent Red 49, 52, 58 and 8. Examples of cyan toner include C.I. I. Pigment Blue 15: 3, 15: 4, and the like, and blue dyes and pigments of copper phthalocyanine and derivatives thereof; C.I. I. And green pigments such as CI Pigment Green 7 and 36 (phthalocyanine green).
[0027]
Among these, cyan toner is C.I. I. Pigment Blue 15: 3 and 15: 4 blue pigments are suitable. For magenta toner, magenta: C.I. I. Pigment Red 57: 1, 122, 146, 184, 238, and Pigment Violet 19 red or red pigments are preferred, and yellow: C.I. I. Pigment Yellow 13, 17, 74, 93, 150, 155, 180, and 185 are preferred. These colorants for color may be used alone or in combination of two or more.
The amount of the colorant used is preferably about 1 to 15 parts by weight, and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
[0028]
In the toner of the present invention, a charge control agent may be used to further impart charge. As a charge control agent for negatively charged toner, a chromium azo complex dye, an iron azo complex dye, a cobalt azo complex dye, salicylic acid or its Chromium / zinc / aluminum / boron complexes or salt compounds of derivatives, chromium / zinc / aluminum / boron complexes or salt compounds of naphtholic acid or derivatives thereof, chromium / zinc / aluminum / boron complexes or salt compounds of benzylic acid or derivatives thereof, Surfactants such as long chain alkyls / carboxylates, long chain alkylsulphonates, etc., as charge control agents for positively charged toners, nigrosine dyes and their derivatives, triphenylmethane derivatives, quaternary ammonium salts , Quaternary phosphonium salt, quaternary pyridinium salt, guanidi Salts, derivatives such as amidine salts are exemplified. These charge control agents may be used singly or in combination of two or more. However, as the charge control agent used for the three primary color toners, a colorless or light-colored one that does not affect the color tone is preferable.
[0029]
The addition amount of the charge control agent is preferably 0.05 to 8 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the binder resin.
Further, as the charge control agent, a negatively charged charge control agent is preferable because the effects of the present invention can be effectively exhibited.
The charge control agent in the present invention is a boron-based charge control agent, particularly a compound represented by the following general formula [I], as a charge control agent for cyan, magenta, and yellow primary color toners, and a black toner charge control agent. As such, an azo metal compound is advantageously used.
[0030]
[Formula 4]

[0031]
(Wherein R₁ ~R_FourIsHydrocarbon groupX⁺Represents a cation. )
Of the compounds represented by the general formula [I], R₁~ R_FourRepresents an optionally substituted hydrocarbon group. Specific examples of the hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, a propylene group and an isopropyl group, and a cycloalkyl group such as a cyclohexyl group and a cyclopentyl group. , Alkenyl groups such as vinyl group and allyl group, and aromatic hydrocarbon groups such as phenyl group and naphthyl group. These hydrocarbons may be substituted, and as the substituent, a halogen atom, a hydroxyl group, a sialic group, an alkyl group, an alkenyl group, and an alkoxy group are preferable.
[0032]
R₁~ R_FourOf which at least two are aromatic hydrocarbon groups and X⁺Is preferably an alkali metal ion. Further, as a commercially available product, a compound known as LR-147 manufactured by Nippon Carlit Co., ie, R₁~ R_FourAre all phenyl groups and X⁺Is particularly preferably a potassium ion.
The amount of the boron compound charge control agent added is preferably 0.05 to 8 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the binder resin.
[0033]
As the metal component of the azo metal compound used in the black toner charge control agent, chromium or iron is preferable.
The addition amount of the charge control agent of these azo-based metal compounds is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 6 parts by weight with respect to 100 parts by weight of the binder resin.
Moreover, as a chromium azo type compound used for this invention, what is represented by the following general formula [II] is preferable, As what is marketed, for example, Bontron S-34 by Orient Chemical Industry Co., Ltd., S-54, Hodogaya Chemical Co., Ltd. T-95, etc. are known.
[0034]
[Chemical formula 5]

[0035]
(In the formula, A to D may be the same or different and represent an optionally substituted benzene ring.⁺Represents a cation. )
In the general formula [II], the substituent on the benzene ring of A to D is preferably an alkyl group, a halogen atom, a cyano group, a nitro group, a hydroxyl group, or an alkoxy group, and more preferably a chlorine atom.
X⁺Represents a cation, preferably a hydrogen ion, an alkali metal ion or an ammonium ion.
The iron / azo compound used in the present invention is preferably a compound represented by the following general formula [III]. Examples of commercially available compounds include T-77 manufactured by Hodogaya Chemical Co., Ltd. It has been known.
[0036]
[Chemical 6]

[0037]
(Wherein E to J may be the same or different and represent an optionally substituted benzene ring.⁺Represents a cation. )
In the general formula [III], when the benzene rings represented by E to J have a substituent, the substituent includes a halogen atom, a sulfonamide group, a mesyl group, a sulfonic acid group, a hydroxyl group, an amino group, and an alkoxycarbonyl group. , An acetylamino group, a benzoylamino group, an optionally substituted hydrocarbon group, an optionally substituted alkoxy group, the alkyl group, alkenyl group, halogen atom, cyano group, hydroxyl group, amino Group and nitro group are preferable, halogen atom and alkoxy group are more preferable, and chlorine atom and methoxy group are particularly preferable.
X⁺Represents a cation, preferably a hydrogen ion, an alkali metal ion or an ammonium ion, more preferably a sodium ion or a potassium ion.
[0038]
In order to improve the dispersibility and compatibility in the toner, the colorant and the charge control agent are pre-dispersed by pre-kneading with the resin in advance, so-called masterbatch treatment, and the resin is added to the pigment dispersion after the pigment formation reaction. May be added to the dispersion medium and the resin at the time of pigment production to mix and disperse the pigment at a high concentration, so-called flushing treatment. The pigment particle diameter in these processed products can be made advantageous in terms of transparency of a color image by dispersing the pigment particle diameter to about a half wavelength (200 nm) of visible light. In addition, the particle size of these processed products is preferably the same as that of the binder resin. If the particle size is too large, uneven distribution of the colorant in the toner tends to occur during continuous production. Usually, the particle size of the master batch processed product and the flushed processed product is a product having passed a sieve having an opening of 3 mm, preferably passing a sieve having an opening of 2 mm or less.
In the present invention, various other known organic or inorganic fine particle powders may be used as other additives for the purpose of modifying the adhesiveness, cohesiveness, fluidity, chargeability, surface resistance, etc. of the toner.
[0039]
The fine powder added to the toner surface, so-called external additive, is preferably an inorganic fine powder surface-treated with at least a silane coupling agent and silicon oil. In these surface treatment agents, hydrophobicity, fluidity, and chargeability are added to the inorganic fine powder, the negative charge buildup in the non-magnetic one-component toner is good, and good charge characteristics can be obtained.
As the core of the inorganic fine powder, it can be selected from silica, titania, alumina, zinc oxide, magnesium oxide, magnetite, ferrite, etc. prepared by a known wet or dry method, preferably silica, titania, and alumina are preferable. More preferably, silica is most preferable.
[0040]
In the case of a non-magnetic one-component toner, one kind of inorganic fine powder may be used, but it is preferable to use two or more kinds having different particle sizes in combination.
In particular, when two or more inorganic fine powders are used in combination in a non-magnetic one-component negatively charged toner, a relatively coarse inorganic fine powder (a) and a relatively fine inorganic fine powder (b) are used. Any one of the inorganic fine powders may be surface-treated with silicon oil. The coarse inorganic fine powder (a) has a BET specific surface area of 80 m.² / G is preferred, more preferably 5 to 79 m.² / G is preferred, and the fine inorganic fine powder (b) has a BET specific surface area of 80 m.² / G or more, more preferably 80 to 500 m² / G is preferred. Furthermore, it is more preferable that the surface treatment agent of the inorganic fine powder (a) is silicon oil and the surface treatment agent of the inorganic fine powder (b) is silicon oil or a coupling agent.
[0041]
The relatively coarse inorganic powder (a) improves the toner blocking resistance, and between the toner particles in the developing tank and between the toner particles and the developing tank constituent members (wall, developing roll, layer thickness regulating member, etc.). There are effects such as suppression of aggregation, suppression of toner pulverization by mechanical impact relaxation, suppression of embedding of external additives, prevention of filming on the photoreceptor, suppression of adhesion phenomenon to the toner layer thickness regulating member, etc. As a result of these estimations, these effects provide excellent storage stability and improve durability performance, such as image deterioration and in-machine contamination due to toner scattering and leakage, even when used in continuous printing. BET specific surface area is 80m² / G or more, the role of the inorganic fine powder (a) as a partition wall between the toner and the developing tank member is hardly exhibited, blocking resistance deteriorates, and durability performance during continuous printing tends to deteriorate. is there. The use of silicon oil as the surface treatment agent for the inorganic fine powder (a) is preferable because it imparts a hydrophobizing function to improve the environment dependency and hardly hinders the chargeability of the toner. In the case of the inorganic fine powder (a) treated with silicon oil, the rising of the charge of the negatively charged toner is improved, and the fog on the photoreceptor and the fog on the plain paper white background are improved. Surface treatment agents other than silicone oil tend to hinder the charging characteristics of the toner.
[0042]
It is estimated that the relatively fine inorganic fine powder (b) has an effect such as an improvement in toner fluidity and an improvement in toner transportability in the developing tank. A high-quality printed matter can be obtained, such as a uniform toner layer at the developing portion and a dense, uniform and good image portion. BET specific surface area is 80m² If it is less than / g, the effect of improving the toner fluidity of the inorganic fine powder (b) is weakened, and as a result, the toner replenishment property is deteriorated, and there is a tendency that a high-quality printed matter cannot be obtained. As a surface treatment agent for the inorganic fine powder (b), a hydrophobic function using a silane coupling agent or silicon oil is imparted to improve the environment dependency, and the fluidity improving function of the inorganic fine powder is excellent. . Surface treatment agents other than silane coupling agents or silicone oil tend to have poor fluidity improving functions.
[0043]
The cores of the inorganic fine powder (a) and the inorganic fine powder (b) may be the same type or different types.
Conventionally known methods are used for the surface treatment of inorganic fine powder with silicon oil. For example, as silicon oil, dimethyl silicone oil, methyl phenyl silicone oil, methyl hydrogen silicone oil, and modified silicone, which are general straight silicone oils, are used. There are methacrylic acid-modified silicone oil, epoxy-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, amino-modified silicone oil, etc., which are oils, and they are used in one kind or a mixture of two or more kinds. The silicone oil is preferably straight silicone oil, and dimethyl silicone oil is particularly preferable.
[0044]
Conventionally known methods are also used for surface treatment of inorganic fine powder with a silane coupling agent. For example, organoalkoxylane (methoxytrimethylsilane, dimethoxyalkoxylane, trimethoxymethylsilane, ethoxytrimethylsilane, etc.) is used as the silane coupling agent. , Organochlorosilanes (trichloromethylsilane, dichlorodimethylsilane, chlorotrimethylsilane, trichloroethylsilane, dichlorodiethylsilane, chlorotriethylsilane, trichlorophenylsilane, etc.), organosilazanes (triethylsilazane, tripropylsilazane, triphenyl) Silazane, hexamethyldisilazane, hexaethyldisilazane, hexaphenyldisilazane, etc.), organodisilazane, organosilane and the like. It used a mixture of more. The silane coupling agent is preferably organochlorosilane or organosilazane. Alternatively, the surface treatment of the silicon oil may be performed after the treatment with the silane coupling agent, and the surface treatment of the silane coupling agent and the silicon oil may be used in combination.
[0045]
The BET specific surface area of the inorganic fine powder can be measured using a commercially available BET specific surface area measuring apparatus by nitrogen adsorption, for example, a flow type automatic specific surface area measuring apparatus (flow soap) manufactured by Shimadzu Corporation. 2300). The average particle size of the inorganic fine powder may be measured from an image taken at a high magnification (for example, 50,000 times or more) that allows the particles to be identified with a transmission electron microscope.
[0046]
Part by weight of inorganic fine powder added as external additive (W₀ ) Is preferably 20 to 400%, more preferably 30 to 300% when the toner particles are 100 parts by weight. When two kinds of inorganic fine powders are used in combination, the added parts by weight of coarse inorganic fine powder (a) (W_a) And added parts by weight of fine inorganic fine powder (b) (W_b) Is the total added weight part W₀ And it is sufficient. Total parts by weight (W₀ However, if the amount is less than this range, the original effect of the inorganic fine powder is not exerted, which is not preferable. If the amount is too large, the filming of the photoconductor is likely to occur, and the fog on the photoconductor and the fog on plain paper are likely to deteriorate. Image defects are likely to occur, which is not preferable. Furthermore, the addition weight part (W of inorganic fine powder (a)_a) And an added weight part of inorganic fine powder (b) (W_b) W_aIs W_bA larger amount is preferable because the effect of a relatively coarse inorganic fine powder can be exerted strongly with a non-magnetic one-component toner._aIs W_bMore preferably 0.2 parts by weight. As the added weight parts of each of the inorganic fine powder (a) and the inorganic fine powder (b), the coverage rate f is calculated individually, and each coverage rate is f ≦ 300, preferably f ≦ 200. If it is more than this, the effects of the inorganic fine powders (a) and (b) are hardly exhibited, and image defects and the like tend to be caused easily.
The coverage f when the toner particles are mixed with one kind of inorganic fine powder is calculated by the following formula [I].
[0047]
[Expression 1]

[0048]
In the formula [I], f is the coverage (%), D_tIs the volume average particle diameter (μm) of the toner particles, d_a, D₀ Is the average particle size (μm) of the inorganic fine powder, ρ_t, Ρ₀ Is the true specific gravity of each of the toner particles and inorganic fine powder.
Further, the coverage f when the toner particles are mixed with two kinds of inorganic fine powders (a) and (b) is calculated by the following formula [II].
[0049]
[Expression 2]

[0050]
In the formula [II], f is the coverage (%), D_tIs the volume average particle diameter (μm) of the toner particles, d_a, D_bIs the average particle size (μm) of each of the inorganic fine powder (a) and the inorganic fine powder (b), ρ_t, Ρ_a, Ρ_bIs the true specific gravity of each of the toner particles, inorganic fine powder (a), and inorganic fine powder (b).
Other external additives for toner include various organic and inorganic fine particles known for the purpose of resistance adjusting agents, abrasives, chargeability adjusting agents, and the like, for example, fluorine resin powders such as polyvinylidene fluoride and polytetrafluoroethylene. , Fatty acid metal salts such as zinc stearate and calcium stearate, resin beads mainly composed of polymethyl methacrylate and silicone resin, minerals such as talc and hydrotalcite, ferroelectric fine powder such as strontium titanate, Examples thereof include conductive fine powders such as conductive titania. These amounts are preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the toner particles.
[0051]
The toner used in the present invention can be produced by various production methods including conventionally known methods, and examples of general production methods include the following.
(1) Disperse the resin, charge control substance, colorant, and additives added as needed, uniformly in a mixing device having rotating parts such as blades and screws in the machine. As the mixing apparatus, a Henschel mixer manufactured by Mitsui Mining Co., Ltd., a Ladige mixer manufactured by Matsubo Co., a Nauter mixer manufactured by Hosokawa Micron Co., a super mixer manufactured by Kawata Co., or a general V-type mixer in which the container itself rotates can be used. .
[0052]
(2) The dispersion is melt-kneaded with a kneader, an extruder, a roll mill or the like. As a kneading apparatus, a continuous extruder, for example, a ZSP extruder manufactured by W & P, a Kneader manufactured by BUSS, a TEM extruder manufactured by Toshiba Machine Co., a PCM extruder manufactured by Ikegai, a kneedex manufactured by Mitsui Mining Co., etc. A general batch kneader can also be used. As a cooling device after kneading, a drum cooler manufactured by Mitsui Mining Co., Ltd./Mitsubishi Chemical Engineering, a belt cooler manufactured by NBC, or the like can be used.
(3) The kneaded product is coarsely pulverized with a coarse pulverizer and then finely pulverized with a fine pulverizer. As pulverizers, jet mills such as NPK I / IDS jet mill, Hosokawa Micron AFG / TJM, etc .; Hosokawa Micron Hammer Mill, Fats Mill, Feather Mill, Inomizer, ACM Pulperizer, Turbo Industries Using an impact mill such as a turbo mill, a KTM manufactured by Kawasaki Heavy Industries, Ltd., a super rotor manufactured by Nissin Engineering Co., Ltd., or a fine mill manufactured by NPK, the toner is pulverized stepwise to a predetermined toner particle size.
[0053]
(4) Classify the finely pulverized product with a classifier. Classifiers include Alpine / Hosokawa Micron TSP, Nisshin Engineering Turboxifier, Condux / Mitsui Mining CFS-HD, Donaldson Donaselex etc. Using a DS / DSX classifier manufactured by NPK, an elbow jet classifier manufactured by Nippon Steel & Mining Co., a micron separator manufactured by Hosokawa Micron, etc., the toner particles are classified stepwise in stages. The coarse powder generated in the classification process may be recycled by returning to the pulverization process or the first classification process. The toner fine powder may be reused after returning to the raw material mixing step and the kneading step.
(5) In the case of further external treatment, a predetermined amount of the classified product and various known external additives are blended, and the mixture is stirred and mixed with a high-speed stirrer that gives shearing force to the powder, such as a Henschel mixer or a super mixer. .
[0054]
(6) Final particles are obtained after sieving using a rotary sieve such as a gyro shifter, a vibrating sieve such as a Sato-type vibrating sieve or an ultrasonic sieve, or a rotary sieve such as a turbo screener to remove foreign matter and coarse particles. be able to.
Further, as a method completely different from the above production method, for example, toner particles may be formed by a suspension polymerization method or an emulsion polymerization method, that is, a so-called polymerization toner method.
The resulting toner preferably has a softening temperature of 80 to 160 ° C. and a glass transition temperature of 50 to 75 ° C. When the softening temperature is less than 80 ° C., the hot offset property is deteriorated and the mechanical strength is unfavorable, and when it exceeds 160 ° C., the fixability is deteriorated. If the glass transition temperature is less than 50 ° C., toner aggregation and fixing are likely to occur, while if it exceeds 75 ° C., the fixing strength is lowered, which is not preferable.
[0055]
In the present invention, the softening temperature (Tc, Tm, Ty) of the full-color three primary color toner is 80 to 160 ° C., the softening temperature (Tb) of the black toner is 80 to 160 ° C., and Tc, Tm, Ty. Is lower than Tb, preferably 3 ° C. or more, and more preferably 3 ° C. or more to 30 ° C. or less. When the softening temperature of the black toner is lower, it is not preferable because a high-gloss color image and a low-gloss black image cannot be obtained.
[0056]
The softening temperature of the toner was determined by using a flow tester (CFT-500, manufactured by Shimadzu Corp.) about 1 g of a sample at a heating rate of 6 ° C./min. 1cm area while heating with² 20kg / cm with a plunger of² The temperature corresponding to the midpoint between the descending start temperature and the descending end temperature of the plunger is set as the softening temperature.
The glass transition temperature (hereinafter referred to as Tg) of the toner is raised to 100 ° C. or higher at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter (DSC) and then cooled to room temperature by air cooling with a fan. The temperature corresponds to the intersection obtained by drawing a tangent to the inflection point (shoulder) when the temperature is raised again.
[0057]
The reason why the toner of the present invention exhibits an excellent effect is not necessarily clear, but is considered as follows. First, color toners are required to be transparent because they may produce colors by mixing multiple colors and ensure transparency during OHP projection. Therefore, it is advantageous to use a toner with a relatively low softening temperature. is there. On the other hand, black does not require transparency because it produces a single black color, but it is advantageous to use a toner having a relatively high softening temperature in order to produce a low gloss black. In black toner wax with a high softening temperature, when the molecular weight of polypropylene wax is relatively high and the melting point is relatively high, shearing tends to occur during kneading, and dispersion of carbon black, charge control agent, etc. is improved and homogeneous. Therefore, it is considered that the reverse polarity is small and the fog on the photoreceptor and the fog on the white background are reduced.
That is, it can be said that the configuration of the present invention satisfies the performance required for the color toner and the black toner in balance when forming a full-color image.
[0058]
The toner used in the full-color image forming method of the present invention may be used as a two-component developer obtained by mixing a toner and a magnetic carrier, or may be used as a one-component toner that does not use a magnetic carrier. It is preferably used as a one-component toner, and more preferably used as a non-magnetic one-component toner.
The full-color image forming method of the present invention is an electrophotographic method in which an image is formed by a thermal fixing method in which development is performed by a contact or non-contact non-magnetic one-component development method and then a toner is brought into contact with a fixing roll having a built-in heater. This is particularly effective when used in a recording apparatus. That is, since a plurality of color toners may be fixed at once with a fixing roll, it is further required to set the softening temperature of the color toner lower. However, according to the configuration of the present invention, sufficient fixing strength can be obtained. It exhibits a useful fixing effect such as no offset phenomenon on the low temperature / high temperature side and no phenomenon of the recording paper being wound around the heat roll.
In particular, the tandem full-color image forming method is characterized in that the printing speed can be increased as compared with the intermediate transfer method and the multiple transfer method. Therefore, as a toner used in the tandem method, a toner having a quick charge rising property, an appropriate charge amount can be secured, a toner fog on the photoreceptor is small, a solid image has good homogeneity, and toner consumption does not deteriorate. It was hoped but not always enough. Therefore, the above problem can be solved by using the toner of the present invention in a tandem system.
[0059]
An electrophotographic recording apparatus using a non-magnetic one-component toner, which is an example of the full-color image forming method of the present invention, will be described below, but is not limited to this example. FIG. 1 is a schematic view of the main configuration of an electrophotographic recording apparatus, which includes a photoreceptor 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6, and a fixing device 7. .
The photoreceptor 1 is formed of a conductor such as aluminum, and a photosensitive layer is formed by applying a photosensitive conductive material to the outer peripheral surface. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the photoreceptor 1.
[0060]
The charging device 2 includes, for example, a well-known scorotron charger, a roller charger, and the like, and uniformly charges the surface of the photoreceptor 1 to a predetermined potential. The exposure device 3 exposes the photosensitive surface of the photoreceptor 1 with an LED, laser light, or the like to form an electrostatic latent image on the photosensitive surface of the photoreceptor 1.
The developing device 4 includes an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and stores toner T therein. If necessary, the developing device may be provided with a replenishing device 41 for replenishing toner, and the replenishing device can replenish toner from a container such as a bottle or a cartridge.
[0061]
The supply roller 43 is made of a conductive sponge or the like and is in contact with the developing roller 44. The developing roller 44 is disposed between the photoreceptor 1 and the supply roller 43. The developing roller 44 is in contact with the photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism. The supply roller 43 carries the stored toner and supplies it to the developing roller 44. The developing roller 44 carries the toner supplied by the supply roller 43 and contacts the surface of the photoreceptor 1.
The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating a metal roll with a silicon resin, a urethane resin, a fluororesin, or the like. The developing roll surface may be smoothed or roughened as necessary.
[0062]
The regulating member 45 is formed of a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating a metal blade with a resin. The regulating member 45 is in contact with the developing roller 44 and pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). The toner may be provided with a function of charging the toner by frictional charging.
The agitator 42 is rotated by a rotation drive mechanism, respectively, and agitates the toner and conveys the toner to the supply roller 43 side. A plurality of agitators may be provided with different blade shapes and sizes.
The transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like disposed so as to face the photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner, and transfers the toner image formed on the photoreceptor 1 onto the recording paper P.
[0063]
The cleaning device 6 is composed of a cleaning member such as a blade such as urethane and a fur brush, and scrapes the residual toner adhering to the photoreceptor 1 with the cleaning member and collects the residual toner.
The fixing device 7 includes an upper fixing member 71 and a lower fixing member 72, and has a heating device 73 inside the upper or lower fixing member. As the fixing member, a known heat fixing member such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon resin is coated, or a fixing sheet can be used. Further, a release agent such as silicone oil may be supplied to the fixing member in order to improve the release property. Further, a mechanism for forcibly applying pressure to the upper fixing member and the lower fixing member by a spring or the like may be used.
When the toner transferred onto the paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated up to a molten state and cooled after passing through the recording paper P. The toner is fixed on the surface.
[0064]
In the electrophotographic developing apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. Subsequently, the photosensitive surface of the photoreceptor 1 after being charged is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, development of the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1 is performed by the developing device 4.
In the developing device 4, the toner supplied by the supply roller 43 is thinned by the developing blade 45 and is triboelectrically charged to a predetermined polarity (here, the same polarity as the charging potential of the photoreceptor 1 and negative polarity). Then, it is carried on the developing roller 44, conveyed, and brought into contact with the surface of the photoreceptor 1.
[0065]
A toner image corresponding to the electrostatic latent image is formed on the surface of the photoreceptor 1 from the developing roller 44 by a so-called reversal developing method. The toner image is transferred onto the paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photosensitive member 1 without being transferred is removed by the cleaning device 6.
The transferred toner on the recording paper P is passed through the fixing device 7 and thermally fixed, so that a final image is obtained.
[0066]
Next, an example of a tandem electrophotographic recording apparatus that uses a non-magnetic one-component toner as a full color will be described. FIG. 2 is a schematic diagram of the main components of the full-color tandem system. The photosensitive member 1, the charging device 2, the exposure device 3, the black developing device 4k, the cyan developing device 4c, the yellow developing device 4y, the magenta developing device 4m, and the transfer device 5. And a fixing device 7, and the cleaning device is omitted here. A color image can be obtained by adjusting magenta, yellow, cyan, and black toners to a desired color by superposing them in multiple layers. In the case of the tandem method, the color development part located before the black development part may reduce color mixing due to reverse transfer of black toner, and the black development part located behind the color development part is only black. In the case of forming an image with a single color, it is preferable that the color mixture of the color toner due to the photoreceptor fog is reduced, and the speed of the black image formation can be increased by short-passing the color developing unit and transporting the recording paper. The toner of the present invention is suitable for a tandem system in which such a cyan, magenta, and yellow color developing portion is in the front position, and the black developing portion is located behind the color developing portion. It should be noted that the order in which the cyan, magenta, and yellow color developing units are positioned can be freely changed in a timely manner.
[0067]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by the following Example, unless the summary is exceeded. In the examples and comparative examples, “parts” simply means “parts by weight”.
[0068]
[Table 1]
[Example 1]
<Preparation of Black Toner K1>
・ Nonlinear polyester resin A1 100 parts
Sp: 150 ° C., Tg: 65 ° C.
THF insoluble matter: 20%
Acid value: 8 KOH mg / g,
Hydroxyl value: 30 KOHmg / g
Mn: 2,400, Mw: 87,000
・ Polypropylene wax p 2 parts
[Mn: 3,000, melting point: 144 ° C., density: 0.89 kg / m^Three ,
Acid value: 0 KOHmg / g]
・ Polyethylene wax b 1 part
[Mn: 3,000, melting point: 129 ° C., density: 0.95 kg / m^Three ]
・ Carbon black Mitsubishi Chemical MA-77 4.5 parts
-Charge control agent T-77 1 part made by Hodogaya Chemical Co., Ltd.
[0069]
The above composition is premixed with a high-speed stirrer, kneaded with a twin-screw continuous extruder, and then rapidly cooled while being rolled with two rolls. The cooled product was coarsely ground with a feather mill until it passed the second mm, and then adjusted to a volume average particle size of about 8.7 μm with a jet pulverizer / airflow classifier to obtain a classified toner. The toner had a softening temperature (Tb) of 140 ° C. and Tg of 65 ° C.
Next, 100 parts of the classified toner and 1.8 parts of RY50 silica manufactured by Nippon Aerosil Co., Ltd. were mixed with a Henschel mixer, and 0.2 part of TG-308F silica manufactured by Cabot Co. was further added and mixed to prepare black toner K1.
[0070]
[Table 2]
<Preparation of Cyan Toner C1>
・ Nonlinear polyester resin A2 100 parts
Sp: 135 ° C., Tg: 63 ° C.
THF insoluble matter: 10%
Acid value: 5 KOH mg / g,
Hydroxyl value: 33 KOHmg / g
Mn: 7,200, Mw: 81,000
・ Polypropylene wax q 2 parts
[Mn: 3,000, melting point: 132 ° C., density: 0.89 kg / m^Three ,
Acid value: 0 KOHmg / g]
・ 10 parts of cyan masterbatch pigment
Cyan pigment C.I. I. Pigment Blue 15: 3
40 parts and 60 parts polyester resin B1 masterbatch
Processed
However, the polyester resin B1 is as follows.
Sp: 110 ° C., Tg: 65 ° C.
Acid value: 7KOHmg / g
Hydroxyl value: 30 KOHmg / g
Mn: 4,400 Mw: 45,000
-Charge control agent LR-147 1 part made by Nippon Carlit
[0071]
A classified toner is prepared in the same manner as Black K1, except that the formulation of Black K1 is as described above, and then 100 parts of the classified toner and 1.8 parts of RY50 silica manufactured by Nippon Aerosil Co., Ltd. are mixed with a Henschel mixer, and further Nippon Aerosil Cyan Toner C1 was prepared by adding 0.2 part of R812 silica manufactured by the company and further mixing. The toner had a softening temperature (Tc) of 125 ° C. and Tg of 64 ° C.
[0072]
[Table 3]
<Preparation of Magenta Toner M1>
・ Magenta master batch pigment 10 parts
In advance, magenta pigment C.I. I. Pigment Red 57: 1
40 parts and 60 parts polyester resin B1 masterbatch
Processed
[0073]
Magenta toner M1 was adjusted by the same operation as cyan C1, except that the master batch pigment of cyan C1 was changed from cyan to the above magenta color. The toner had a softening temperature (Tm) of 127 ° C. and Tg of 64 ° C.
[0074]
[Table 4]
<Preparation of Yellow Toner Y1>
・ 10 parts of yellow color master batch pigment
In advance, yellow pigment C.I. I. Pigment Yellow 17
40 parts and 60 parts polyester resin B1 masterbatch
Processed
[0075]
The yellow toner Y1 was adjusted by the same operation as cyan C1, except that the master batch pigment of cyan C1 was changed from cyan to yellow as described above. The toner had a softening temperature (Ty) of 125 ° C. and Tg of 63 ° C.
Using these K1, C1, M1, and Y1 toners, a commercially available full color printer A with a tandem mechanism (A4 plain paper color speed of 12 sheets / minute; non-magnetic one-component contact development system for both three primary colors and black toners; Table 1 shows the results of image characteristics evaluation in the order of magenta, cyan, yellow, and black; the photoconductor is an organic photoconductor; and the fixing temperature of plain paper is 190 ° C. in the heat roll fixing method. The results of evaluating the offset property in the external fixing machine using cyan C1 of the primary color toner are shown in the table, but all were excellent and good.
[0076]
[Table 5]

[0077]
[Table 6]

[0078]
[Table 7]
[Example 2]
<Preparation of Black Toner K2>
・ Polypropylene wax (oxidized type) r 2 parts
[Mn: 3,000, melting point: 145 ° C., density: 0.89 kg / m^Three ,
Acid value: 3.5 KOHmg / g]
[0079]
A black toner K2 was prepared in the same manner as K1, except that the polypropylene wax p of the black toner K1 of Example 1 was changed to the polypropylene wax r described above. The toner had a softening temperature (Tb) of 141 ° C. and Tg of 64 ° C.
The fixing property of the black toner K2 was good, and the image characteristics were evaluated with the full-color printer A by using it together with the three primary color toners C1, M1, and Y1, but they were all excellent and good.
[0080]
[Table 8]
[Example 3]
<Preparation of Black Toner K3>
・ 2 parts of polypropylene wax
[Mn: 4,000, melting point: 147 ° C., density: 0.89 kg / m^Three ,
Acid value: 0 KOHmg / g]
[0081]
A black toner K3 was produced in the same manner as in K1, except that the polypropylene wax p of the black toner K1 of Example 1 was changed to the polypropylene wax s described above. The toner had a softening temperature (Tb) of 140 ° C. and Tg of 64 ° C.
The fixing property of the black toner K3 was good, and the image characteristics were evaluated with the full-color printer A by using it together with the three primary color toners C1, M1, and Y1, but all were excellent and good.
[0082]
[Table 9]
[Comparative Example 1]
<Preparation of Black Toner K4>
A black toner K4 was produced in the same manner as the toner K1 except that the polypropylene wax p of the black toner K1 of Example 1 was omitted (the number of added parts was 0). The toner had a softening temperature (Tb) of 141 ° C. and Tg of 65 ° C. As a result of evaluating the image characteristics with the full color printer A using the black toner K4 and the three primary color toners C1, M1, and Y1 of Example 1, the fog on the photosensitive member and the fog on the white background are bad. The low temperature side offset generation temperature was not preferable because it was as high as 140 ° C.
[0083]
[Table 10]
[Comparative Example 2]
<Preparation of Black Toner K5>
・ Polypropylene wax q 2 parts
[Mn: 3,000, melting point: 132 ° C., density: 0.89 kg / m^Three ,
Acid value: 0 KOHmg / g]
[0084]
A black toner K5 was produced in the same manner as in K1, except that the polypropylene wax p of the black toner K1 of Example 1 was changed to the polypropylene wax q described above. The toner had a softening temperature (Tb) of 140 ° C. and Tg of 64 ° C.
The black toner K5 and the three primary color toners C1, M1, and Y1 of Example 1 were used to evaluate the image characteristics with the full color printer A. As a result, the fog on the photoreceptor was remarkably bad and the fog on the white background was bad, which was not preferable.
[0085]
[Table 11]
[Comparative Example 3]
<Production of Cyan C2, Magenta M2, Yellow Y2 Toner>
-Polypropylene wax t 2 parts
[Mn: 4,000, melting point: 147 ° C., density: 0.89 kg / m^Three ,
Acid value: 0 KOHmg / g]
[0086]
Cyan C2, magenta M2, and yellow Y2 were prepared in the same manner as the corresponding colors except that the three primary color toners cyan C1, magenta M1, and yellow Y1 of polypropylene wax q of Example 1 were changed to the polypropylene t. The softening temperature / Tg of these toners was 125 ° C./64° C. for C2, 127 ° C./64° C. for M2, and 126 ° C./64° C. for Y2. As a result of evaluation with an external fixing device using cyan C2 among the three primary color toners, the high temperature side offset generation temperature is as low as 210 ° C. Further, these three primary color toners C2, M2, Y2 and the black toner K1 of Example 1 were used. As a result of using the full color printer A and evaluating the image characteristics, the image density of the three primary color toners was lowered, which was not preferable.
[0087]
[Table 12]
[Example 4]
・ Charge control agent S-34 1 part, Orient Chemical Industry Co., Ltd.
[0088]
A black toner K6 was prepared by the same operation as in Example 1 except that the charge control agent in Example 1 was changed to S-34 instead of T-77. The toner had a softening temperature (Tm) of 140 ° C. and Tg of 64 ° C.
The fixability of the toner K6 is good, and the image characteristics were evaluated with the full-color printer A when used together with the three primary color toners C1, M1, and Y1. As a result, the fog on the photosensitive member was slightly higher than 2.0. Was almost good.
[0089]
[Evaluation Method] The test method for each evaluation item was as follows.
1. Image density
The reflection density of an image portion printed using plain paper with a predetermined full color printer is measured with a spectrocolorimetric densitometer X-Rite 938 (light source: D65 light source, viewing angle 2 °, response: T) manufactured by Nihon Hakusho Kaisha, The image density was used.
2. White background
Print with plain paper using a specified full-color printer, measure the XYZ of the white background, which is a non-image area, with a color difference meter Z-Σ80 manufactured by Nippon Denshoku Industries Co., Ltd. I asked for a cover.
[0090]
[Equation 3]
White ground fog (ΔZ_w) = Z_p-Z_i
Z_i: White background Z value before printing
Z_p: White background Z value after printing
[0091]
3. Cover on photoconductor
Put the toner of the specified full color printer and print in white paper mode using plain paper, forcibly stop in the middle of printing, fog on the photoconductor (position after the development part on the photoconductor and before the transfer part) Toner) is collected with a 3M company's mending tape, and is then affixed to plain paper (white paper). The cover part of the affixed tape is L with a spectrocolorimetric densitometer X-Rite 938 (light source: D65 light source, viewing angle 2 °, response: T) manufactured by Nihon Hakusho Kaisha.^*a^*b^*Measured before and after the fogging^*a^*b^*From the color difference (△ E₂ ) And made it a white background.
[0092]
[Expression 4]
Color difference (△ E₂ ) = [(L^* _j-L^* _q)² + (A^* _j-A^* _q)² + (B^* _j-B^* _q)² ]^1/2
L^* _j, A^* _j, B^* _j: Tape value before collecting fog
L^* _q, A^* _q, B^* _q: Tape value after collecting fog
[0093]
4). Glossiness
A solid image was printed on plain paper with a predetermined full-color printer, and the gloss value measured with a gloss meter VG-2000 (angle 75 °) manufactured by Nippon Denshoku Industries Co., Ltd. was taken as the glossiness.
5. Offset property with external fixing
A square solid image is previously collected by the full-color printer A in an unfixed state (hereinafter referred to as an unfixed image).
Next, an external fixing unit composed of an upper fixing roller having a diameter of 25 mm covered with a top layer with Teflon (with a temperature-controllable heater incorporated therein) and a lower fixing roller having a diameter of 18 mm with the uppermost layer covered with silicon rubber. Using the machine, the surface temperature of the upper fixing roller is measured with a radiation thermometer, and the temperature is changed with a 5 ° C scratch. At this time, the upper and lower fixing roller nip width is about 3 mm, and no release agent such as silicone oil is supplied. The passing speed when using plain paper was 56 mm / sec.
An unfixed image was passed for each temperature to obtain a fixed image, and the temperature at which the low temperature side offset and the high temperature side offset occurred was measured from the state of occurrence of the offset.
[0094]
【The invention's effect】
According to the present invention, in a full-color image forming method used in an electrophotographic recording apparatus or the like, toner charging characteristics are good, image characteristics such as image density and fog are good, and durability characteristics are stable and good even when continuously printed. In addition, the fixing property in heat fixing is also good, and an excellent effect is exhibited.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of the main configuration of an electrophotographic recording apparatus using a non-magnetic one-component toner, which is an example of a full-color image forming method of the present invention.
FIG. 2 is a schematic diagram showing the main configuration of an electrophotographic recording apparatus used in a full-color tandem method, which is an example of the full-color image forming method of the present invention.
[Explanation of symbols]
1 Photoconductor
2 Charging device
3 Exposure equipment
4 Development device
5 Transfer device
6 Cleaning device
7 Fixing device
4k black developing device
4y yellow developing device
4c Cyan developing device
4m magenta developing device
41 Supply device
42 Agitator
43 Supply roller
44 Developing roller
45 Restriction member
71 Upper fixing member
72 Lower fixing member
73 Heating device
T Toner
P Recording paper

Claims (27)

In a full-color image forming method for forming a color image using a plurality of color toners and black toners, the plurality of color toners and black toners contain a binder resin, polypropylene wax , a colorant, and a charge control agent, A full color wherein the softening temperatures of the plurality of color toners are all lower than the softening temperature of the black toner, and the melting point of the polypropylene wax in the plurality of color toners is lower than the melting point of the polypropylene wax in the black toner Image forming method. In a full-color image forming method for forming a color image using a plurality of color toners and black toners, the plurality of color toners and black toners contain a binder resin, polypropylene wax , a colorant, and a charge control agent, The softening temperatures of the plurality of color toners are all lower than the softening temperature of the black toner, and the number average molecular weight of the polypropylene wax in the plurality of color toners is lower than the number average molecular weight of the polypropylene wax in the black toner. A full color image forming method. In full-color image forming method for forming a color image using three primary toner and the black toner of cyan, magenta, yellow, the three primary toner and black toner, respectively it binding Chakujushi, polypropylene wax, a colorant, and a charge A cyan toner softening temperature (Tc), magenta toner softening temperature (Tm), and yellow toner softening temperature (Ty) are all lower than the black toner softening temperature (Tb). The melting point (MPc) of the polypropylene wax in the toner, the melting point (MPm) of the polypropylene wax in the magenta toner, and the melting point (MPy) of the polypropylene wax in the yellow toner are all lower than the melting point (MPb) of the polypropylene wax in the black toner. A full-color image forming method.  In a full-color image forming method for forming a color image using cyan, magenta, and yellow three primary color toners and a black toner, each of the three primary color toners and the black toner includes at least a binder resin, a polypropylene wax, a colorant, and charge control. The cyan toner softening temperature (Tc), the magenta toner softening temperature (Tm), and the yellow toner softening temperature (Ty) are all lower than the black toner softening temperature (Tb), and in the cyan toner. The number average molecular weight (Mnc) of the polypropylene wax, the number average molecular weight (Mnm) of the polypropylene wax in the magenta toner, and the number average molecular weight (Mny) of the polypropylene wax in the yellow toner are all the numbers of the polypropylene wax in the black toner. Characterized by lower than average molecular weight (Mnb) A full-color image forming method. Full-color image forming method according to any one of claims 1 to 4, characterized in that the range melting point of both 90 to 160 ° C. polypropylene wax of the color toner and the black toner. Full-color image forming method according to any one of claims 1 to 5, wherein the number-average molecular weight of the polypropylene wax of the color toner and the black toner is in the range of 2,000 to 10,000 both . The addition amount of the polypropylene wax of the color toner and the black toner is any one of claims 1 to 6, characterized in that both a 0.1 to 6 parts by weight per 100 parts by weight of the binder resin A full-color image forming method described in 1. The full-color image forming method according to any one of claims 1 to 7 , wherein the binder resin is a styrene resin or a polyester resin. Full-color image forming method according to any one of claims 1 to 7, wherein the binder resin is a linear or non-linear polyester resin. The binder resin for the color toner is a linear or nonlinear polyester resin,
The full-color image forming method according to claim 9, wherein the binder resin for black toner is a non-linear polyester resin. 11. The softening temperature (Tc, Tm, Ty) of the three primary color toners and the softening temperature (Tb) of the black toner are all in the range of 80 to 160 ° C. 11. A full-color image forming method described in 1. The three primary toner softening temperature (Tc, Tm, Ty) full color according to either one of claims 3 to 11, characterized in that 3 ° C. or more lower than any black toner softening temperature (Tb) Image forming method. The colorant of the cyan toner is at least cyan: C.I. I. The full-color image forming method according to any one of claims 3 to 12 , comprising a blue pigment of CI Pigment Blue 15: 3 or 15: 4. The colorant of the magenta toner is at least magenta: C.I. I. Pigment Red 57: 1, 122, 146, 184, 238, or to any one of claims 3 to 12, characterized in that it comprises either a red or bright red pigment Pigment Violet 19 The full-color image forming method described. The colorant of the yellow toner is at least yellow: C.I. I. Pigment Yellow 13, 17, 74, 93, 150, 155, 180, or to any one of claims 3 to 12, characterized in that it comprises one of the yellow pigment 185 The full-color image forming method described. Full-color image forming method according to any one of claims 1 to 15 colorant of the black toner is characterized in that it comprises at least carbon black or magnetite. Full-color image forming method according to any one of claims 1 to 16, wherein the charge control agent is negatively chargeable charge control agent. The charge control agent for the three primary color toners of cyan, magenta and yellow is at least a charge control agent of the following general formula [I], and the charge control agent for black toner is an azo metal compound. 15. The full-color image forming method according to any one of 1 to 14.

(In the formula, R ₁ to R ₄ represent hydrocarbon groups , and X ⁺ represents a cation.) The charge control agent for the three primary color toners is represented by the general formula [I] wherein R _{1 to} R ₄ are phenyl groups, X ⁺ is a potassium ion, and the metal component in the azo metal compound of the black toner is chromium, full-color image forming method according to any one of claims 1 to 18, characterized in that iron. The full-color image forming method according to claim 18 or 19, wherein the azo metal compound charge control agent of the black toner is a compound represented by the following general formula [II].

(In the formula, A to D may be the same or different and each represents an optionally substituted benzene ring. X ⁺ represents a cation.) The full-color image forming method according to claim 18 or 19, wherein the azo metal compound charge control agent of the black toner is a compound represented by the following general formula [III].

(Wherein E to J may be the same or different and represent an optionally substituted benzene ring, and X ⁺ represents a cation.) The full-color image forming method according to any one of claims 3 to 21 , wherein the three primary color toners and the black toner are fixed by a heating contact method. Full-color image forming method according to any one of claims 3 to 22, wherein the three primary toner and the black toner is developed by the one-component developing method.  24. The full-color image forming method according to claim 23, wherein the one-component developing method of the three primary color toners is a non-magnetic one-component developing method comprising at least a developing roll and a toner layer regulating member. Full-color image forming method according to any one of claims 1 to 24 wherein the full-color image forming method is characterized by being used in tandem.  26. In the tandem system, a developing unit for cyan, magenta, and yellow primary color toners is positioned in front, and a developing unit for black toner is positioned after the developing unit for three primary colors. Full color image forming method. Full-color image forming method according to any one of claims 1 to 26, wherein the colorant of the black toner is acidic carbon black.

Images