JP3700263B2 - One-component developer and image forming method - Google Patents

Description

（式中、Ｒは炭素数１〜３のアルキル基を表し、Ｒ’はアルキル基、ハロゲン変性アルキル基、フェニル基、変性フェニル基を表し、Ｒ”は炭素数１〜３のアルキル基又はアルコキシ基を表し、ｍ、ｎは整数を表す。）
【００２８】
これらのシリコーンオイルとしては、例えば、ジメチルシリコーンオイル、アルキル変性シリコーンオイル、α−メチルスルホン変性シリコーンオイル、クロルフェニルシリコーンオイル、フッ素変性シリコーンオイル、アミノ変性シリコーンオイル等が挙げられる。
また、本発明に用いるシリコーンワニスとしては、例えば、メチルシリコーンレジンからなるワニス、メチルフェニルシリコーンレジンからなるワニス等が挙げられる。
【００２９】
また、これらのオイル又はワニスで処理されるシリカは、ケイ素ハロゲン化合物の蒸気相酸化により生成された乾式シリカや水ガラスから生成された湿式シリカのいずれも使用可能である。シリコーンオイル又はシリコーンワニスの処理方法としては、公知の技術が使用できる。例えば、シリカ粉末とシリコーンオイル又はシリコーンワニスを混合機を用いて混合する方法、シリカ粉末中にシリコーンオイルを噴霧器を用いて噴霧する方法、溶液中にシリコーンオイル又はシリコーンワニスを溶解させた後、シリカ粉末を混合する方法等が挙げられる。
処理量は、シリカ粉末１００重量部に対して５乃至３０重量部が好ましく用いられる。シリコーンオイル又はシリコーンワニスで処理された後のシリカは、ＢＥＴ比表面積で２０乃至３００ｍ² ／ｇの範囲のものが好ましく用いられる。特に３０乃至２００ｍ² ／ｇの範囲のものが好ましい。比表面積が２０ｍ² ／ｇ未満では、トナー表面に十分に付着することが困難となりやすく、転写中抜けの防止効果は発揮されにくく、３００ｍ² ／ｇを超えると、凝集性が高くなり、トナー表面への分散性が弱く、流動性が低下しやすい。
【００３０】
また、トナーに添加されるシリコーン処理シリカの量は、トナー粒径、現像剤担持体の組成等により異なるが、トナー１００重量部に対して、処理シリカ０．１〜５．０重量部、より好ましくは０．２〜２．０重量部である。処理シリカの量が０．１重量部未満の場合は、十分な流動性が得られず転写性が悪化し、画像中抜けが生じ、また、処理シリカの量が５．０重量部を越える場合では、環境安定性が悪化し環境により画像濃度の違いが生じるだけでなく、現像機の各部材に融着し帯電不良、画質欠陥の原因となる。また、定着像の強度が弱くなったり、光沢性が低下するといった問題が生じる。
【００３１】
本発明における添加剤中に含有されるチタン化合物とシリコーン処理シリカとの混合割合（重量部）は１：０．２〜１：５、望ましくは、１：０．３〜１：３、より望ましくは１：０．５〜１：２である。チタン化合物１重量部に対して、シリコーン処理シリカの量が０．２重量部よりも少ないと、感光体への付着性、トナー凝集性が増加し、画像中抜けが生じやすくなり、一方、チタン化合物１重量部に対して、シリコーン処理シリカの量が５重量部を超えると、環境安定性が悪化し、環境により画像濃度が変化し、安定した画像が得られない。
【００３２】
本発明の一成分系現像剤は、上記した添加剤と共にトナー粒子とからなる。トナー粒子は、非磁性一成分系現像剤の場合、結着樹脂と着色剤を主要成分とし、磁性一成分系現像剤の場合、結着樹脂と着色剤と磁性体とを主要成分とする。
トナー粒子に使用される結着樹脂としては、従来使用されている公知の合成樹脂，天然樹脂を用いることができる。例えば、スチレン、クロロスチレン等のスチレン類、エチレン、プロピレン、ブチレン、イソプレン等のモノオレフィン、酢酸ビニル、プロピオン酸ビニル、安息香酸ビニル、酪酸ビニル等のビニルエステル、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸ドデシル、アクリル酸オクチル、アクリル酸フェニル、メタクリル酸メチル、メタクリル酸エチル、メタクリル酸ブチル、メタクリル酸ドデシル等のαーメチレン脂肪族モノカルボン酸エステル類、ビニルメチルエーテル、ビニルエチルエーテル、ビニルブチルエーテル等のビニルエーテル類、ビニルメチルケトン、ビニルヘキシルケトン、ビニルイソプロペニルケトン等のビニルケトン類、それら単独重合体あるいは共重合体を例示することができ、特に代表的な結着樹脂としては、ポリスチレン、スチレンーアクリル酸アルキル共重合体、スチレンーメタクリル酸アルキル共重合体、スチレンーアクリルニトリル共重合体、スチレンーブタジエン共重合体、スチレンー無水マレイン酸共重合体、ポリエチレン、ポリプロピレン等をあげることができる。さらに、ポリエステル、ポリウレタン、エポキシ樹脂、シリコーン樹脂、ポリアミド、変性ロジン、パラフィンワックス等を挙げることができる。
【００３３】
本発明におけるトナー粒子に含有される着色剤としては、カーボンブラック、アニリンブルー、カルコイルブルー、クロムイエロー、ウルトラマリンブルー、ヂュポンオイルレッド、キノリンイエロー、メチレンブルークロリド、銅フタロシアニン、マラカイトグリーンオキサレート、ランプブラック、ローズベンガル、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ４８：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ １２２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｒｅｄ ５７：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ９７、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １２、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ １７、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １５：１、Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ １５：３等の公知の着色剤が使用可能である。
【００３４】
本発明における磁性一成分現像剤のトナー粒子の磁性体としては、従来から一般的に使われている公知の磁性体であれば如何なるものでも使用することができる。例えば、鉄、コバルト、ニッケル等の金属およびこれらの合金、Ｆｅ₃ Ｏ₄ 、γ−Ｆｅ₂ Ｏ₃ 、コバルト添加参加鉄等の金属酸化物、ＭｎＺｎフェライト、ＮｉＺｎフェライト等の各種フェライトにより形成されるものが使用される。これらの磁性体は、シランカップリング剤やチタネートカップリング剤等のカップリング剤や、シリカ、アルミナなどの無機微粒子、脂肪酸化合物、樹脂等の有機化合物が表面に処理されていてもよく、粒径は、一般に０．０５〜０．５μｍの範囲が適当である。これらの磁性体の形状は、八面体、六面体、球形のものが使用される。また、本発明において、磁性体の含有量は、３０〜７０重量％の範囲で用いられ、好ましくは４０〜６０重量％である。含有量が３０重量％未満であると、特に低温低湿環境下では、画像濃度の低下やカブリが生じ、７０重量％を越えると、トナーの定着性が悪化し、実用上不都合を生じる。
また、トナー粒子には、グロス、オフセット性をより良好にするために、離型剤を添加しても良い。離型剤としては、炭素数８以上のパラフィン、ポリオレフィン等が好ましく、例えばパラフィンワックス、パラフィンラテックス、マイクロクリスタリンワックス等、又はポリプロピレン、ポリエチレン等が挙げられ、これらを単独あるいは併用して用いる。離型剤の添加量はトナー粒子中に０．３〜１０重量部の範囲が好ましく用いられる。添加量が０．３重量部未満の場合は定着時に十分に離型剤として作用しない。また、１０重量部を越えるとトナー表面上の離型剤露出が多くなるため、帯電不良を生じ現像剤担持体からのトナー飛散や画質低下を生じる。また、トナー相互間付着力もしくは層形成部材や現像剤担持体との相互作用が大きくなるためにクリーニング性に問題が生じる。
【００３５】
本発明において、必要に応じてトナー粒子中に帯電制御剤を添加してもよい。帯電制御剤としては、公知のものを使用できるが、フッ素系界面活性剤、サリチル酸金属錯体、アゾ系金属化合物のような含金属染料、マレイン酸を単量体成分として含む共重合体のごとき高分子酸、第四級アンモニウム塩、ニグロシン等のアジン系染料、カーボンブラック、あるいは帯電制御樹脂等が用いられ、トナー１００重量部に対し０．１〜１０重量部の範囲で添加することが好ましい。
【００３６】
本発明に用いるトナー粒子の粒径は、体積平均粒径で５〜１３μｍが好ましい。体積平均粒径が５μｍ未満では流動性が著しく悪化するため層形成がうまく出来ず、カブリやダートの原因となり、１３μｍを越えると、解像度が低下し高画質が得られなくなる。さらに、現像剤の単位重量当たりの帯電量が低下するため、層形成維持性が悪くカブリやダートが発生し易くなる。
本発明に用いるトナーは、公知の如何なる方法によっても製造できるが、特に、混練、粉砕方式が好ましい。即ち、結着樹脂と着色剤、離型剤等をニーダーやエクストルーダーなどの混練機にて溶融混練し、冷却後粉砕、分級を行う方法が好ましい。
【００３７】
本発明において、シリコーンオイル又はシリコーンワニス処理シリカ、チタン化合物はトナー粒子に添加し、混合されるが、これらの混合は、例えばＶ型ブレンダーやヘンシェルミキサー、レディゲミキサー等によって行うことができる。また、この際必要に応じて種々の添加剤を添加しても良い。これらの添加剤としては、酸化セリウム、マグネタイト等の研磨材やポリスチレン微粒子、ポリメチルメタクリレート微粒子、ポリフッ化ビニリデン微粒子等のクリーニング助剤もしくは転写助剤等が挙げられる。更に必要に応じ、振動篩分機、風力篩分機などを使って、トナーの粗大粒子を取り除いても一向にかまわない。
【００３８】
次に本発明の一成分系現像剤を用いた画像形成方法について説明する。
本発明の一成分系現像剤は、例えば、潜像担持体上に潜像を形成する工程、該潜像担持体上に現像剤担持体上に層形成された一成分系現像剤を用いてトナー像を形成する工程、該トナー像を転写体上に転写する工程、および転写体上のトナー画像を熱定着する定着工程を有するガス形成装置に用いられる。
潜像形成工程は、従来公知の方法が適用でき、電子写真法あるいは静電記録法によって、感光層あるいは誘電体層等の潜像保持体の上に静電潜像を形成する。本発明に用いる潜像保持体の感光層としては、有機系、アモルファスシリコン等公知のものが使用できる。また、その円筒状保持体としては、アルミニウム又はアルミニウム合金を押出し成型後、表面加工する等の公知の製法により得られる。
【００３９】
現像工程は、トナー担持体（現像ロール）としての回転円筒体上に、トナーを弾性ブレード等にて薄層形成して現像まで搬送し、現像ロールと静電潜像を保持する潜像保持体とを現像部にて接触の状態で配置し、又は一定の間隙を設けて非接触の状態で配置し、現像ロールと潜像保持体との間にバイアスを印加しながら静電潜像をトナーで現像する。磁性一成分系現像剤の場合、トナー担持体として内部には磁石が内蔵された回転円筒体が使用される。
【００４０】
本発明に用いるトナー担持体としては、シリコンゴムなどの弾性体スリーブ、アルミ、ＳＵＳ、ニッケル等の金属やセラミックスを引き抜きしたスリーブおよびトナーの搬送性や帯電性を制御するため基体表面の酸化または金属メッキ、研磨、ブラスト処理等の表面処理や樹脂によるコーティングなどを施したものが使用され、特にアルミ、ＳＵＳ、ニッケル等の金属やセラミックスを引き抜きしたスリーブを使用したときには、本発明の効果は著しいものとなる。現像ロールにおけるトナー層形成は弾性ブレードをスリーブ表面に当接させて行う。弾性ブレードの材質はシリコーンゴム、ウレタンゴム等のゴム弾性体が好ましく用いられ、トナー帯電量をコントロールするために弾性体中に有機物または無機物を添加・分散させてもよい。
【００４１】
転写工程は、潜像保持体上のトナー画像を転写体（例えば、紙等）に転写する。本発明における転写手段としては、潜像保持体に転写ローラーや転写ベルトなどを圧接させる接触型のものと、コロトロンを用いる非接触型のもの等公知のものがあげられるが、装置の小型化オゾン発生防止の点で接触型が好ましい。
【００４２】
クリーニング工程は、転写工程にて転写されずに潜像保持体に残ったトナーを、クリーナーにより除去する。本発明におけるクリーニング手段としては、ブレードクリーニングまたはローラークリーニングなどの公知のものがあげられる。ブレードクリーニングは、シリコーンゴムやウレタンゴムなどの弾性ゴムが用いられる。
定着工程は、転写体に転写されたトナー画像を定着器にて定着する。定着手段としては、ヒートロールを用いる熱定着方式が一般に使用されている。
【００４３】
【実施例】
以下、実施例により本発明をさらに具体的に説明するが、本発明はこれらの実施例に限定されるものではない。なお、以下の説明において、特に断りのない限り、『部』はすべて『重量部』を意味する。
本特許は、湿式法で生成される酸化チタン、即ち硫酸法、塩酸法が適用されるが、実施例で用いるチタン化合物はイルメナイトを鉱石として用い、硫酸に溶解させ鉄分を分離し、ＴｉＯＳＯ₄ を加水分解してＴｉＯ（ＯＨ）₂ を生成させる湿式沈降法を用いた。
本調整でのキー技術は核生成のための加水分解と分散調整及び水洗であり、特に分散処理におけるｐＨ調整（酸の中和）、スラリー濃度の調整は、後のチタン化合物の一次粒子を決めるものであり、高いレベルの制御が必要である。
【００４４】
（チタン化合物Ａの調整）
上記手法で生成されたＴｉＯ（ＯＨ）₂ １００部に対し、イソブチルトリメトキシシラン４０重量部を混合し、熱をかけて反応させた。その後、水洗、ろ過を行い１２０℃で乾燥させた後、ピンミルでソフト凝集をほぐし平均粒径５０ｎｍ、抵抗５．９×１０⁹ Ω・ｃｍのチタン化合物Ａを得た。
（チタン化合物Ｂの調整）
粒径調整のためｐＨ調整、分散調整を換え、イソブチルトリメトキシシラン５０重量部を混合した以外は同様な手法で平均粒径３０ｎｍ、抵抗３．６×１０⁸ Ω・ｃｍのチタン化合物Ｂを得た。
（チタン化合物Ｃの調整）
イソブチルトリメトキシシランをテトラメトキシシラン４０部に変えた以外は、外添剤Ａと同様な手法で．平均粒径５０ｎｍ、抵抗４．２×１０⁹ Ω・ｃｍのチタン化合物Ｃを得た。
【００４５】
（チタン化合物Ｄの調整）
イソブチルトリメトキシシランをジフェニルジクロロシラン４０部に変えた以外は、外添剤Ｂと同様な手法で平均粒径３０ｎｍ、抵抗８．４×１０¹⁰Ω・ｃｍのチタン化合物Ｄを得た。
（チタン化合物Ｅの調整）
イソブチルトリメトキシシランをデシルトリメトキシシラン４０部に変えた以外は、外添剤Ａと同様な手法で平均粒径５０ｎｍ、抵抗２．４×１０¹⁰Ω・ｃｍのチタン化合物Ｅを得た。
（チタニア粒子Ｆの調整）
上記手法で調整されたＴｉＯ（ＯＨ）₂ を水洗、ろ過後、焼成し、平均粒径５０ｎｍ、抵抗４．３×１０⁶ Ω・ｃｍの酸化チタンを得た。この後、ジェットミルにて粉砕し、外添剤Ｆを得た。
【００４６】
（チタニア粒子Ｇの調整）
外添剤Ｆをメタノール中に分散し、チタニア１００重量部に対し、イソブチルトリメトキシシラン４０重量部を混入、サンドグラインダーにて湿式粉砕後、ニーダーにて撹拌しながら溶剤を除き、乾燥して抵抗５．４×１０⁸ Ω・ｃｍの外添剤Ｇを得た。
（チタニア粒子Ｈの調整）
上記手法で調整されたＴｉＯ（ＯＨ）₂ を水洗、ろ過後、焼成し、平均粒径３０ｎｍの酸化チタンを得た。この後再び水中に分散し、サンドグラインダーにて湿式粉砕し、その後水中にて、イソブチルトリメトキシシラン５０重量を混入させ、撹拌、熱かけ乾燥を行い、ジェットミルにて粉砕し、抵抗３．４×１０⁸ Ω・ｃｍの外添剤Ｈを得た。
【００４７】
シリカ粒子Ｉの調整
ジメチルシリコーンオイル２０部をエタノール３００部に溶解し、平均一次粒子径１２ｎｍのシリカ微粒子１００部と攪拌混合した後、エバポレーターを用いてエタノールを除き、乾燥後、乳鉢を用いてシリカ微粒子を解砕し１０５μｍのふるいで篩分してＢＥＴ比表面積１２０ｍ² ／ｇシリコーンオイル処理シリカ粒子Ｉを調整した。
シリカ粒子Ｊの調整
ジメチルシリコーンオイル１０部をエタノール３００部に溶解し、平均一次粒子径６０ｎｍのシリカ微粒子１００部と攪拌混合した後、エバポレーターを用いてエタノールを除き、乾燥後、乳鉢を用いてシリカ微粒子を解砕し１０５μｍのふるいで篩分してＢＥＴ比表面積５０ｍ² ／ｇシリコーンオイル処理シリカ粒子Ｊを調整した。
【００４８】
次にトナー粒子を製造した。このトナーの粒度は、コールターカウンター社製粒度測定器ＴＡＩＩ、アパーチャー径１００μｍで測定した。
＜磁性トナー粒子１の製造＞

上記材料をヘンシェルミキサーで混合した後、エクストルーダーにて溶融混練した。冷却後、粗粉砕した後、ジェットミルにて微粉砕し、さらにこの粉砕物を風力分級して体積平均粒径Ｄ５０が８．８μｍの分級品を得た。
【００４９】
＜非磁性トナー粒子２の製造＞

上記材料をヘンシェルミキサーで混合した後、エクストルーダーにて溶融混練した。冷却後、粗粉砕した後、ジェットミルにて微粉砕し、さらにこの粉砕物を風力分級して体積平均粒径Ｄ５０が９．２μｍの分級品を得た。
【００５０】
実施例１
トナー粒子１：１００部に対して、シリカ粒子Ｉ：０．５部、チタン化合物Ａ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤１を得た。
実施例２
トナー粒子１：１００部に対して、シリカ粒子Ｉ：０．５部、チタン化合物Ｂ：０．８部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤２を得た。
実施例３
トナー粒子１：１００部に対してシリカ粒子Ｊ：０．５部、チタン化合物Ｃ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤３を得た。
【００５１】
実施例４
トナー粒子１：１００部に対して、シリカ粒子Ｊ：０．５部、チタン化合物Ｄ：０．８部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤４を得た。
実施例５
トナー粒子１：１００部に対して、シリカ粒子Ｉ：０．７５部、チタン化合物Ｅ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤５を得た。
【００５２】
比較例１
トナー粒子１：１００部に対して、シリカ粒子Ｉ：０．５部、チタニア粒子Ｆ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤６を得た。
比較例２
トナー粒子１：１００部に対して、シリカ粒子Ｉ：０．５部、チタニア粒子Ｇ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤７を得た。
比較例３
トナー粒子１：１００部に対して、シリカ粒子Ｊ：０．５部、チタニア粒子Ｈ：０．８部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し、現像剤８を得た。
比較例４
トナー粒子１：１００部に対して、疎水性シリカＲ９７２（アエロジル社製）０．５部、チタニア粒子Ｈ：０．８部をヘンシェルミキサーにて外添混合し、更風力篩分機にて１０６μｍで篩分し、現像剤９を得た。
【００５３】
図１に、磁性一成分現像剤の画質評価に用いた画像形成装置を示す。
潜像保持体１をローラー帯電器２で帯電させた後、レーザー光で露光し静電潜像を形成し、内部にマグネットを有するアルミ製現像剤担持体３上にウレタンゴム製の層形成ブレード４にて薄層形成された現像剤にて感光体と非接触で現像する。潜像保持体１上に現像されたトナーは接触型の転写ローラー５により転写紙に転写され定着器６で熱定着される。潜像保持体上の残留トナーのクリーニングはブレード式クリーナー７を用いた。ここで感光体（潜像保持体）１の周速は１００ｍｍ／ｓ、現像剤担持体３の周速は１５０ｍｍ／ｓとし、現像剤担持体３には交流電圧と直流電圧とをかけて静電潜像を現像するようにした。
図１の画像形成装置を用いて、得られた現像剤１〜９を２８℃、８５％ＲＨの高温高湿環境下および１０℃、３０％ＲＨの低温低湿環境下にて１万枚のプリントテストを行った。その結果を、表１に示す。
【００５４】
実施例６
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部、チタン化合物Ａ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１０を得た。
実施例７
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部、チタン化合物Ｂ０．８部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１１を得た。
実施例８
トナー粒子２：１００部に対して、シリカ粒子Ｊ：１．５部、チタン化合物Ａ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１２を得た。
実施例９
トナー粒子２：１００部に対して、シリカ粒子Ｊ：１．５部、チタン化合物Ｃ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１３を得た。
実施例１０
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部、チタン化合物Ｅ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１４を得た。
【００５５】
比較例５
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部、チタニア粒子Ｆ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１５を得た。
比較例６
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部、チタニア粒子Ｇ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１６を得た。
比較例７
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部、チタニア粒子Ｈ：０．８部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１７を得た。
比較例８
トナー粒子２：１００部に対して、疎水性シリカＲ９７２（アエロジル社製）１．３部、チタニア粒子Ｇ：１．０部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１８を得た。
比較例９
トナー粒子２：１００部に対して、シリカ粒子Ｉ：１．３部をヘンシェルミキサーにて外添混合し、更に風力篩分機にて１０６μｍで篩分し現像剤１９を得た。
【００５６】
図２に、非磁性一成分現像剤の画質評価に用いた画像形成装置を示す。
潜像保持体１をローラー帯電器２で帯電させた後、レーザー光で露光し静電潜像を形成し、アルミ製現像剤担持体３上にウレタンゴム製の層形成ブレード４にて薄層形成された現像剤にて感光体と非接触で現像する。ここでトナーの搬送を安定化させるために、現像剤担持体３と逆方向に回転する現像剤供給ローラー８を現像剤担持体３に接触して配置した。潜像保持体１上に現像されたトナーは接触型の転写ローラー５により転写紙に転写され定着器６にて熱定着される。潜像保持体上の残留トナーのクリーニングはブレード式クリーナー７を用いた。ここで感光体１の周速は１００ｍｍ／ｓ、現像剤担持体３の周速は１７０ｍｍ／ｓとし、現像剤担持体３と現像剤供給ローラー５には交流電圧と直流電圧とをかけて静電潜像を現像するようにした。
図２の画像形成装置を用いて、得られた現像剤１０〜１９を２８℃、８５％ＲＨの高温高湿環境下および１０℃、３０％ＲＨの低温低湿環境下にて１万枚のプリントテストを行った。その結果を、表２に示す。
【００５７】
＜トナー流動性＞
オフラインオーガーデイスペンサーを用いトナーの流動性を評価した。デイスペンス量≧７００ｍｇ／ｓｅｃの場合は○、それ以外は×とした。
＜帯電性環境差＞
高温高湿帯電量／低温低湿帯電量を求めその数値が０．７以上の場合を○、０．５以上０．７未満の場合を△、０．５未満の場合を×と評価した。
〔トナーの帯電量〕
東芝ケミカル社製ブローオフ帯電量測定器を使用し、１００μｍの鉄粉３０ｇとトナー１．２ｇをターブラミキサーにて６０秒攪拌後測定した。測定環境は、温度２２℃／湿度５５％ＲＨで行った。
【００５８】
〔チタン化合物の比重〕
ルシャテリエ比重瓶を用いＪＩＳ−Ｋ−００６１，５−２−１に準拠し測定した。操作は次の通りである。
ルシェテリエ比重瓶に約２５０ｍｌの水を入れ、メニスカスが目盛りの位置にくるように調整する。比重瓶を恒温水槽に浸し、液温が２０．０±０．２℃になったとき、メニスカスの位置を比重瓶の目盛りで正確に読み取る（精度０．０２５ｍｌとする）。試料約１００ｇを１ｍｇの桁まで量り取り、その質量をＷとする。量り取った試料を比重瓶に入れ泡を除く。比重瓶を恒温水槽に浸し、液温を２０．０±０．２℃に保ち、メニスカスの位置を比重瓶の目盛りで正確に読み取る（精度０．０２５ｍｌとする）。
比重は次の方法で算出される。
Ｄ＝Ｗ／（Ｌ₂ −Ｌ₁ ）
Ｓ＝Ｄ／０．９９８２
ここに、
Ｄ：試料の密度（２０℃）（ｇ／ｃｍ³ ）
Ｓ：試料の比重（２０／２０℃）
Ｗ：試料の見かけの質量（ｇ）
Ｌ₁ ：試料を比重瓶に入れる前のメニスカスの読み（２０℃）（ｍｌ）
Ｌ₂ ：試料を比重瓶に入れた後のメニスカスの読み（２０℃）（ｍｌ）
０．９９８２：２０℃における水の密度（ｇ／ｃｍ³ ）
【００５９】
＜カブリ＞
５０倍のルーペで背景部観察して感応評価した。全くなし、若干あり、かなりありをそれぞれ○、△、×と評価した。
＜濃度維持性＞
Ｘ−ＲＩＴＥ社製の濃度測定器Ｘ−ＲＩＴＥ４０４Ａにより、濃度測定を行った。○は１．３以上、△は１．３未満１．１以上、×は１．１未満を示す。
＜スリーブ筋・画像中抜け・フィルミング・トナー飛散、ゴースト＞
それぞれの状態を目視にて評価した。全くなし、若干あり、かなりありをそれぞれ○、△、×と評価した。
【００６０】
【表１】

【００６１】
【表２】

【００６２】
【発明の効果】
以上説明したように、本発明の一成分現像剤は、帯電性、帯電速度、環境依存性、帯電分布、現像剤担持体上のトナーの帯電維持性、スリーブ汚染、感材傷・汚染等の一成分トナーに要求されるすべての特性を満足する為、長期に渡り画像濃度変動、低現像性、カブリ、画像中抜け画質結果等の問題を発生しない優れた画質を得ることが可能である。
【図面の簡単な説明】
【図１】本発明が適用される磁性一成分系現像装置の好ましい一実施の形態を示す概略的構成図である。
【図２】本発明が適用される非磁性一成分系現像装置の好ましい一実施の形態を示す概略的構成図である。
【符号の説明】
１ 潜像担持体（感光体）
２ ローラー帯電器
３ 現像剤担持体
４ 層形成ブレード
５ 転写ローラ
６ 定着器
７ クリーナー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a one-component developer and an image forming method. More specifically, the developer is formed into a thin layer on a developer carrying member, conveyed to a developing unit, and an electrostatic latent image on a latent image holding member is developed. The present invention relates to an image forming method using a one-component image forming apparatus having a process of developing and a developer used in the method.
[0002]
[Prior art]
In recent years, the electrophotographic dry development system has been used not only with an electrostatic copying machine, but also with a printer, a facsimile, or a multifunction machine having both a copying machine and a printer and a facsimile. In particular, as a recent trend, ecological measures such as stronger downsizing, lighter weight, resource saving and recycling are required. In order to cope with this, improvement and new development of an image forming method and a developer used in the image forming method have been performed. As dry development methods in various electrostatic copying systems that are currently in practical use, a two-component development method using a carrier such as toner and iron powder and a development method using a one-component developer not using a carrier are known. Yes.
[0003]
The two-component development method is the most widely used method at present, but only the toner is consumed, and the concentration ratio of the toner in the developer is lowered. Therefore, the mixing ratio with the carrier must be kept constant. Therefore, an apparatus such as a controller is required for this purpose, and there is a disadvantage that the developing device is enlarged. Therefore, the one-component development method that does not use a carrier does not have the above-described drawbacks, and is advantageous for reducing the size and weight of the apparatus.
[0004]
The one-component toner developing method is classified into a magnetic one-component developing method using magnetic toner and a non-magnetic one-component developing method using non-magnetic toner.
In the magnetic one-component development method, a magnetic toner is held on a developer carrier having a magnetic field generating means such as a magnet inside, and a thin layer of magnetic toner is formed using an elastic blade such as silicone rubber, so that electrostatic latent It is developed by attaching toner to the electrostatic latent image on the image carrier, and has been put into practical use in recent years because of easy toner conveyance control and low internal contamination of copying machines, printers, etc. . However, the magnetic toner used in the magnetic one-component developing system has a disadvantage that it cannot cope with the full color which has been increasingly demanded in the market in recent years because it contains a black or brown colored magnetic material such as magnetite. .
[0005]
On the other hand, in the non-magnetic one-component development system, non-magnetic toner is supplied onto the developer carrying member by a toner supply roller and an agitator adjacent to the developer carrying member, a toner layer is formed by a layer regulating blade, and then a static layer is formed. Development is performed by attaching toner to the electrostatic latent image on the electrostatic latent image holding member, and is a development method suitable for colorization because the toner does not require a colored magnetic material. Further, since a magnet is not used for the developer carrying member, it is possible to reduce the weight and cost, and in recent years it has begun to be put into practical use in a small full color printer or the like.
[0006]
By the way, the one-component toner developing system does not have a stable toner charging / conveying means called a carrier as compared with the two-component developing system, and therefore, the toner is required to have stricter characteristics. In particular, non-magnetic one-component development has no magnetic force for toner conveyance / layer formation, so it is necessary to hold the toner on the developer carrier mainly by electrostatic force, and the toner is charged more quickly and uniformly. There is also a demand for good fluidity to form a stable layer. If these required characteristics are not sufficient, image density reduction, fogging, development ghost, in-machine contamination and the like due to continuous use tend to be problems.
[0007]
In addition to these characteristics related to toner development, various characteristics have been required for toners in recent years to reduce the size and weight of the apparatus, to improve image quality, and to support ecology. For example, in order to prevent the generation of ozone, contact-type bias rolls and the like are becoming mainstream in place of conventional corotrons for charging of photoreceptors and toners. In order to prevent fusing, high transfer efficiency / high cleaning properties are required, and in order to prevent character streaking with a contact-type transfer roll, toner must have good adhesion / aggregation characteristics, fluidity, etc. The
[0008]
Conventionally, in one-component development, means for adding fine inorganic oxide powder such as silica to a toner has been used for the purpose of improving fluidity and chargeability in order to stabilize the charging and conveyance of the toner. However, in the case of generally used silica-based fine powders, the toner fluidity improvement effect is particularly excellent, but the negative polarity is strong, and the charge of the negatively charged toner is excessively increased particularly under low temperature and low humidity. Even if a positive charge such as nitrogen-containing compound treatment is applied, it is not suitable for a positively charged toner, and further, it takes in moisture under high temperature and high humidity to reduce the chargeability, so there is a large difference in chargeability in each environment. It will occur. As a result, the transportability and chargeability of the toner onto the developer carrying member cannot be optimized at both high temperature and high humidity and low temperature and low humidity, resulting in poor image density reproduction, background fog, and toner blur. There was a problem that it would fall and cause in-flight contamination. For example, JP-A-46-5782, JP-A-48-47345, JP-A-48-47346, JP-A-59-34539, JP-A-59-198470, JP-A-59. JP-A No. 231550 discloses hydrophobizing the surface of silica fine particles. However, only using these inorganic fine powders does not provide a sufficient effect especially in chargeability.
[0009]
Further, as a method for alleviating the negative chargeability of the toner particles, silica fine particles surface-treated with amino-modified silicone oil are externally added (Japanese Patent Laid-Open No. 64-73354) and aminosilane and / or amino-modified silicone oil. A method of externally adding surface-treated silica fine particles (JP-A-1-237561) is known. However, although treatment with these amino compounds can suppress an excessive charge increase of the negatively chargeable toner particularly under low temperature and low humidity, the environmental dependency of the silica fine powder itself cannot be sufficiently improved.
Furthermore, as described above, particularly in the non-magnetic one-component development method, it is necessary that the developer has a high charging speed. However, when an amount that gives the developer sufficient fluidity is added, the high resistance of the silica fine powder, Mainly due to high chargeability, slow charging speed, etc., the distribution of charge on the developer carrier is widened, and there are many negative polarity toners even if the charge amount falls within the suitable range It also has reverse fog and toner cloud (dirt inside the machine).
As described above, even if the silica fine particles are subjected to a hydrophobizing treatment, a treatment for reducing negative chargeability, etc., they have not yet improved the environmental dependency of the charge, the charging speed, and the poor charge distribution of silica. Is the current situation.
[0010]
On the other hand, it has been proposed to add silica fine powder treated with silicone oil to the toner as a method for preventing the character dropout phenomenon caused by the contact-type transfer roll. Although this method improves the character dropout phenomenon, the toner charge distribution cannot be improved as described above, and it is difficult to achieve compatibility with fog, toner cloud, and the like.
[0011]
On the other hand, if the inorganic oxide added for the purpose of charging and fluidity is titania, which is generally used, the charging speed is faster than that of silica, and the charge distribution is sharp because of the low resistance of titania. Has characteristics. Further, these additions suppress the developer charge-up, and the ghost phenomenon is also suppressed. However, when titania is added, high charge cannot be imparted to the toner, and it is easy to cause a decrease in the transport amount due to continuous use, a decrease in density reproducibility due to a decrease in charge, background fogging, and in-machine contamination.
[0012]
In order to improve the charging property, a method of externally adding hydrophobic titanium oxide to the toner has been proposed. (Japanese Patent Laid-Open Nos. 58-216252, 60-123862, and 60-238847). Hydrophobic titanium oxide can be obtained by treating the surface with a silane compound, a silane coupling agent, silicone oil or the like. Although this method can certainly increase the chargeability of untreated hydrophilic titania, the charge level can be improved to some extent depending on the type and amount of the treatment agent in one-component toner. The level is not yet satisfactory, and there are limits to environmental dependence. In addition, by increasing the hydrophobicity of titanium oxide with the treatment agent, the improvement of the charge level and the environment dependency are certainly superior to the conventional hydrophilic titanium oxide, but conversely the charging speed of titanium oxide The actual situation is that the speed and the sharpness of the charge distribution are greatly inferior to those of conventional titanium oxide.
[0013]
Titanium oxide is mainly obtained by extracting titanium oxide crystals from ilmenite ore by the sulfuric acid method or hydrochloric acid method. These are purified by a wet method and obtained through heating and firing. Naturally, the resulting chemical bonds also exist, and it is not easy to redisperse such agglomerated particles with existing techniques. That is, the titanium oxide taken out as fine powder formed secondary and tertiary aggregates, and the effect of improving the fluidity of the toner was significantly inferior to that of silica. In particular, there is an increasing demand for high image quality in the market, such as color, and attempts have been made to reduce the particle size of the toner to achieve high image quality. The liquidity will be deteriorated.
[0014]
Therefore, in order to achieve both improvement in fluidity and environmental dependence of charging, addition of a combination of hydrophobic titanium oxide and hydrophobic silica has been attempted. (Japanese Unexamined Patent Publication No. 60-136755). Although this method temporarily suppresses the respective disadvantages of hydrophobic silica and hydrophobic titanium oxide, it is easily affected by either additive depending on the dispersion state. In particular, in consideration of maintainability, it is difficult to stably suppress the dispersion structure on the toner surface, and the characteristics of hydrophobic silica or hydrophobic titanium oxide are likely to appear due to stress on the sleeve. That is, it has been difficult to stably control each defect over a long period of time. Therefore, in a method of purifying titanium oxide by a wet method, there is a method in which a silane compound is hydrolyzed in an aqueous medium, the surface of titanium oxide is treated, titanium oxide is taken out in a state where aggregation is suppressed, and added to the toner. It has been proposed (Japanese Patent Laid-Open No. 5-188633). When this method is used, silane compound treatment reduces the amount of agglomerated particles compared to the conventional method of hydrophobizing titanium oxide. In other words, the toner fluidity is improved, but the charge level and environmental dependence of the negatively charged toner are obtained. Is not different from conventional ones, and is not sufficient in the intended high negative chargeability and environment dependency, and further has an adverse effect on the charge rate and charge distribution.
[0015]
[Problems to be solved by the invention]
As described above, the conventional techniques have various problems, and it is difficult to overcome them.
The present invention has been made for the purpose of solving the problems all at once in view of the above circumstances.
That is, it is a first object of the present invention to provide a one-component developer which can obtain a high image quality with stable toner charge amount and transport amount and little fogging over a long period of use.
The second object of the present invention is to provide a one-component developer having excellent fluidity and environmental stability.
A third object of the present invention is to provide a one-component developer that is free from development ghosts and has good transferability and high image quality without voids.
A fourth object of the present invention is to provide an image forming method capable of obtaining a stable high image quality without density change, fogging, ghosting and image omission using a one-component developer having the above-described characteristics. .
[0016]
[Means for Solving the Problems]
As a result of various studies to solve the above problems, the present inventors, as a result, in a one-component developer comprising toner particles containing at least a binder resin and a colorant and an additive, a specific silica in the additive is included. It has been found that when a powder and a specific titanium compound are used in combination, a stable image can be obtained over a long period of time without problems of density change, fogging, ghosting and image omission.
The present invention has been achieved on the basis of the above knowledge, and the one-component developer of the present invention is a one-component system comprising toner particles containing a binder resin and a colorant and an additive. In the developer, the additive is TiO (OH)₂It contains a titanium compound obtained by the reaction of a silane compound and silica treated with silicone oil or silicone varnish.
The image forming method of the present invention includes a step of forming a latent image on a latent image carrier, a step of developing the latent image using a developer on the developer carrier, and a transfer of the developed toner image. In an image forming method having a step of transferring onto a body, the one-component developer described above is used as the developer.
The image forming method of the present invention further comprises a step of forming a latent image on a latent image carrier and a step of developing the latent image using a developer on the developer carrier. The carrier and the latent image carrier are developed in a non-contact state, and the one-component developer described above is used as the developer.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The one-component developer of the present invention is a one-component developer comprising toner particles containing a binder resin and a colorant and an additive, that is, a non-magnetic one-component developer and a magnetic one-component developer. In the agent, the additive is TiO (OH)₂And a titanium compound obtained by a reaction between the silane compound and silica treated with silicone oil or silicone varnish.
The titanium compound contained in the additive is TiO (OH)₂This TiO (OH) is obtained by the reaction of silane compound₂Is preferably a titanium compound produced by a wet method and having a specific gravity of 2.8 to 3.6. When the specific gravity of the titanium compound is less than 2.8, the titanium compound is less detached from the toner, but the reaction between the processing agents increases, so that the processing agent is easily peeled off from the titanium compound, so that The toner tends to be low-charged due to filming or sleeve contamination. Further, when the specific gravity of the titanium compound is larger than 3.6, the reaction between the processing agents hardly occurs, so that the processing agent does not peel off, but the titanium compound itself is easily peeled off from the toner, and the photosensitive material is likely to adhere. Become.
[0018]
In general, the production method of titanium oxide by an ordinary wet method is produced through a chemical reaction in a solvent, and can be divided into a sulfuric acid method and a hydrochloric acid method.
If the sulfuric acid method is simplified, the following reaction proceeds in the liquid phase, and insoluble TiO (OH)₂Is produced by hydrolysis.
FeTiO_Three+ 2H₂SO_Four  → FeSO_Four+ TiOSO_Four+ 2H₂O
TiOSO_Four+ 2H₂O → TiO (OH)₂+ H₂SO_Four
In addition, the hydrochloric acid wet method produces titanium tetrachloride by chlorination in the same manner as the dry method. It is then dissolved in water and hydrolyzed while adding a strong base, and TiO (OH)₂Is produced. The following is a simplified example.
TiCl_Four+ H₂O → TiOCl₂+ 2HCl
TiOCl₂+ 2H₂O → TiO (OH)₂+ 2HCl
[0019]
In the normal titanium oxide production process, washing with water and filtration are repeated thereafter, and titanium oxide is obtained by firing. Further, after pulverization and pulverization, a treatment such as a silane compound is performed as necessary. However, this conventional production of titanium oxide has a serious drawback in that particles are sintered due to the strength of bonding between Ti in the firing step, and a large number of agglomerates are generated. In order to solve this serious drawback, many contrivances have been made such as strengthening of wet pulverization and treatment agent reaction before drying. However, it is not possible to break up this agglomeration to primary particles. Even if this titanium oxide is applied as a toner additive, even if the coverage on the toner is combined with silica particles, fluidity similar to silica cannot be obtained, and this phenomenon seems to be caused by aggregation of particles, As a result, sensitive material scratches and filming occur.
[0020]
Further, titanium oxide treated by a conventional production method has a limit in the amount that can be treated in the treatment of a silane compound. In general, increasing the amount of the silane compound increases the chargeability-imparting ability, but the ability is saturated at a treatment amount of 15 to 20% with respect to the amount of titanium oxide. Therefore, even if the amount of the coupling agent is increased in order to give a high charge, not only high charge cannot be obtained, but also when there is a further increase in aggregated particles due to the reaction between excess coupling agents, and further when added to the toner This leads to a decrease in charging speed, broadening of the charge distribution, and the like. As described above, the conventional titanium oxide is not at a level that can satisfy all of the agglomerated particles, the high charging ability, the slow charging speed, and the charge distribution.
[0021]
However, the titanium compound in the present invention is TiO (OH) produced in the wet process described above.₂It is prepared by reacting and drying a silane compound. Therefore, since it does not pass through the firing process of several hundred degrees, a strong bond between Ti is not formed, there is no aggregation, and the particles can be taken out in a state of primary particles. Furthermore, the titanium compound in the present invention is TiO (OH).₂Since the silane compound is directly reacted with the silane compound, the amount that can be treated can be increased. In other words, the conventional treated titanium oxide has a low limit value of the treatment amount that contributes to the charging ability, but the titanium compound used in the present invention has a high limit value and depends on the particle size of the raw material, In general, the amount of treatment can be increased to about 3 times the amount of conventional products (about 50 to 70% of the titanium base). Therefore, the charge of the toner can be controlled by the amount of treatment with the silane compound, and the chargeability that can be imparted can be greatly improved over the conventional titanium oxide. Furthermore, since the excess silane compound is reduced, that is, the reaction between the silane compounds is small, high charge can be obtained without sacrificing the charge rate and charge distribution even when the treatment amount is increased.
[0022]
The titanium compound used in the present invention has a resistance of 10 for controlling toner charge distribution for improving fog and developing property.⁸-10¹²Ω · cm is used. Resistance is 10⁸If it is less than Ω · cm, the chargeability of the toner is remarkably reduced, causing fogging and toner scattering.¹²If it exceeds Ω · cm, the charge distribution of the toner becomes broad, and fogging due to the reverse polarity toner, two-layered toner layer on the developer carrying member due to the highly charged toner, and development ghost are likely to occur.
[0023]
In addition, the present titanium compound has an average primary particle diameter of 100 nm or less, preferably in the range of 10 nm to 70 nm. If the average primary particle diameter is less than 10 nm, the particles tend to aggregate and the dispersibility in the toner particles tends to be reduced. On the other hand, if the average primary particle diameter exceeds 100 nm, the imparting of fluidity to the toner may be reduced.
[0024]
  Examples of the silane compound used in the present invention include chlorosilane and alkoxysilane.NIt is also possible to use different types. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyl Triethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilanerun,Vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3.4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycol Sidoxypropylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane can be exemplified, but the treating agent in the present invention is not limited to these compounds.
[0025]
The amount of silane compound treated is TiO (OH)₂Generally, TiO (OH) varies depending on the primary particle size of₂The amount of the silane compound is in the range of 5 to 80 parts by weight, more preferably 10 to 50 parts by weight with respect to 100 parts by weight of the base. When the processing amount is less than 5 parts by weight, the function of the silane compound to be processed does not function, and when the processing amount exceeds 80 parts by weight, the excess silane compound is converted to oil and the toner fluidity is reduced. Starts to malfunction. However, the treatment with the silane compound is aimed at imparting high charge to the toner, improving the environment dependency, improving the toner fluidity, and reducing the photosensitive material interaction. , TiO (OH)₂It is necessary to adjust appropriately from the balance of the particle size of the raw material.
[0026]
The amount of the additive (titanium compound) added to the toner varies depending on the toner particle size, developer carrier composition, etc., and is 0.1 to 3.0 parts by weight with respect to 100 parts by weight of the toner. More preferably, it is 0.2-2.0 weight part. If the amount is less than 0.1 parts by weight, the fluidity of the toner cannot be obtained. If the amount exceeds 3.0 parts by weight, in the fixing step, the fixing temperature is increased and the fixing strength is decreased. When it is used in full color, it interferes with the color developability of the overlaid base color due to a decrease in light transmittance, and when used for OHP or the like that transmits light, the transparency and color developability are lowered.
[0027]
Moreover, the silica processed by silicone oil or silicone varnish is used for the additive in this invention with the above-mentioned titanium compound. By using the silica, an appropriate fluidity can be imparted to the toner, and the adhesion between the toner and the photoreceptor can be reduced, and the toner can be transferred more favorably to prevent the image from being lost.
As a silicone oil used for this invention, what is represented by General formula (1) is preferable.
[Chemical 1]

(In the formula, R represents an alkyl group having 1 to 3 carbon atoms, R ′ represents an alkyl group, a halogen-modified alkyl group, a phenyl group, or a modified phenyl group, and R ″ represents an alkyl group having 1 to 3 carbon atoms or an alkoxy group. Represents a group, and m and n represent integers.)
[0028]
Examples of these silicone oils include dimethyl silicone oil, alkyl-modified silicone oil, α-methylsulfone-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil, and amino-modified silicone oil.
Moreover, as a silicone varnish used for this invention, the varnish which consists of a methylsilicone resin, the methylphenyl silicone resin, etc. are mentioned, for example.
[0029]
As the silica treated with these oils or varnishes, either dry silica produced by vapor phase oxidation of silicon halogen compounds or wet silica produced from water glass can be used. A well-known technique can be used as a processing method of silicone oil or silicone varnish. For example, a method of mixing silica powder and silicone oil or silicone varnish using a mixer, a method of spraying silicone oil into silica powder using a sprayer, and after dissolving silicone oil or silicone varnish in a solution, silica Examples include a method of mixing powder.
The treatment amount is preferably 5 to 30 parts by weight with respect to 100 parts by weight of silica powder. Silica after being treated with silicone oil or silicone varnish has a BET specific surface area of 20 to 300 m.²Those in the range of / g are preferably used. Especially 30 to 200m²Those in the range of / g are preferred. Specific surface area is 20m²If it is less than / g, it tends to be difficult to sufficiently adhere to the toner surface, and the effect of preventing transfer dropout is hardly exhibited.²When it exceeds / g, the cohesiveness becomes high, the dispersibility on the toner surface is weak, and the fluidity tends to be lowered.
[0030]
The amount of the silicone-treated silica added to the toner varies depending on the toner particle size, the composition of the developer carrier, etc., but the amount of treated silica is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the toner. Preferably it is 0.2-2.0 weight part. When the amount of the treated silica is less than 0.1 parts by weight, sufficient fluidity cannot be obtained, transferability is deteriorated, the image is lost, and the amount of the treated silica exceeds 5.0 parts by weight. However, not only does the environmental stability deteriorate and the image density varies depending on the environment, but it is fused to each member of the developing machine, causing charging defects and image quality defects. Further, there arises a problem that the strength of the fixed image becomes weak and the glossiness is lowered.
[0031]
The mixing ratio (parts by weight) of the titanium compound and the silicone-treated silica contained in the additive in the present invention is 1: 0.2 to 1: 5, preferably 1: 0.3 to 1: 3, more preferably. Is 1: 0.5 to 1: 2. If the amount of silicone-treated silica is less than 0.2 parts by weight relative to 1 part by weight of the titanium compound, adhesion to the photoreceptor and toner cohesion will increase, and image voids will easily occur. When the amount of the silicone-treated silica exceeds 5 parts by weight with respect to 1 part by weight of the compound, the environmental stability deteriorates, the image density changes depending on the environment, and a stable image cannot be obtained.
[0032]
The one-component developer of the present invention comprises toner particles together with the above-described additives. In the case of a non-magnetic one-component developer, the toner particles include a binder resin and a colorant as main components, and in the case of a magnetic one-component developer, the toner particles include a binder resin, a colorant, and a magnetic material as main components.
As the binder resin used for the toner particles, conventionally known synthetic resins and natural resins can be used. For example, styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, methyl acrylate, ethyl acrylate, acrylic Α-methylene aliphatic monocarboxylic acid esters such as butyl acid, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl methyl ether, vinyl ethyl ether, Examples include vinyl ethers such as vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone, and homopolymers or copolymers thereof. Examples of binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, Examples thereof include polyethylene and polypropylene. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.
[0033]
As the colorant contained in the toner particles in the present invention, carbon black, aniline blue, calcoyl blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Yellow 97, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 17, C.I. I. Pigment Blue 15: 1, C.I. I. A known colorant such as Pigment Blue 15: 3 can be used.
[0034]
As the magnetic material of the toner particles of the magnetic one-component developer in the present invention, any known magnetic material generally used in the past can be used. For example, metals such as iron, cobalt, nickel, and alloys thereof, Fe_ThreeO_Four, Γ-Fe₂O_ThreeIn addition, metal oxides such as cobalt-added iron, etc., and those formed of various ferrites such as MnZn ferrite and NiZn ferrite are used. These magnetic materials may have a surface treated with a coupling agent such as a silane coupling agent or a titanate coupling agent, an inorganic fine particle such as silica or alumina, an organic compound such as a fatty acid compound, or a resin. Is generally in the range of 0.05 to 0.5 μm. The shape of these magnetic bodies is octahedral, hexahedral, or spherical. Moreover, in this invention, content of a magnetic body is used in 30 to 70 weight%, Preferably it is 40 to 60 weight%. When the content is less than 30% by weight, the image density is lowered or fogged particularly in a low-temperature and low-humidity environment, and when it exceeds 70% by weight, the toner fixing property is deteriorated, resulting in practical inconvenience.
Further, a release agent may be added to the toner particles in order to improve gloss and offset properties. As the mold release agent, paraffin having 8 or more carbon atoms, polyolefin and the like are preferable, and examples thereof include paraffin wax, paraffin latex, microcrystalline wax and the like, or polypropylene and polyethylene, and these are used alone or in combination. The amount of release agent added is preferably in the range of 0.3 to 10 parts by weight in the toner particles. When the addition amount is less than 0.3 parts by weight, it does not sufficiently act as a release agent at the time of fixing. On the other hand, when the amount exceeds 10 parts by weight, the exposure of the release agent on the surface of the toner increases, so that charging failure occurs, causing toner scattering from the developer carrying member and image quality degradation. Further, since the adhesion force between the toners or the interaction between the layer forming member and the developer carrier increases, there arises a problem in the cleaning property.
[0035]
In the present invention, a charge control agent may be added to the toner particles as necessary. As the charge control agent, known ones can be used. However, a high charge such as a fluorosurfactant, a metal-containing dye such as a salicylic acid metal complex or an azo metal compound, or a copolymer containing maleic acid as a monomer component. Molecular acids, quaternary ammonium salts, azine dyes such as nigrosine, carbon black, charge control resins, and the like are used, and are preferably added in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the toner.
[0036]
The toner particles used in the present invention preferably have a volume average particle diameter of 5 to 13 μm. If the volume average particle size is less than 5 μm, the fluidity is remarkably deteriorated, so that the layer cannot be formed well, causing fog and dirt. If it exceeds 13 μm, the resolution is lowered and high image quality cannot be obtained. Further, since the charge amount per unit weight of the developer is lowered, the layer formation maintenance is poor and fog and dirt are likely to occur.
The toner used in the present invention can be produced by any known method, and a kneading and pulverizing method is particularly preferable. That is, a method in which a binder resin, a colorant, a release agent and the like are melt-kneaded with a kneader such as a kneader or an extruder, and pulverized and classified after cooling is preferable.
[0037]
In the present invention, silicone oil or silicone varnish-treated silica and a titanium compound are added to the toner particles and mixed. The mixing can be performed by, for example, a V-type blender, a Henschel mixer, a Redige mixer or the like. In this case, various additives may be added as necessary. Examples of these additives include abrasives such as cerium oxide and magnetite, cleaning aids such as polystyrene fine particles, polymethyl methacrylate fine particles, and polyvinylidene fluoride fine particles, or transfer aids. Further, if necessary, the toner particles may be removed by using a vibration sieving machine, a wind sieving machine, or the like.
[0038]
Next, an image forming method using the one-component developer of the present invention will be described.
The one-component developer of the present invention uses, for example, a step of forming a latent image on a latent image carrier, and a one-component developer layered on the developer carrier on the latent image carrier. It is used in a gas forming apparatus having a step of forming a toner image, a step of transferring the toner image onto a transfer body, and a fixing step of thermally fixing the toner image on the transfer body.
A conventionally known method can be applied to the latent image forming step, and an electrostatic latent image is formed on a latent image holding member such as a photosensitive layer or a dielectric layer by electrophotography or electrostatic recording. As the photosensitive layer of the latent image carrier used in the present invention, known ones such as organic and amorphous silicon can be used. Further, the cylindrical holding body can be obtained by a known production method such as surface processing after extrusion molding of aluminum or an aluminum alloy.
[0039]
In the development step, a latent image holding body that holds a developing roll and an electrostatic latent image by forming a thin layer on a rotating cylindrical body as a toner carrying body (developing roll) with an elastic blade and transporting the toner to development. Are arranged in contact with each other in the developing unit, or are arranged in a non-contact state with a certain gap, and the electrostatic latent image is transferred to the toner while applying a bias between the developing roll and the latent image holding member. Develop with. In the case of a magnetic one-component developer, a rotating cylinder having a magnet built therein is used as a toner carrier.
[0040]
Examples of the toner carrier used in the present invention include an elastic sleeve such as silicon rubber, a sleeve obtained by extracting a metal such as aluminum, SUS, or nickel, or a ceramic, and oxidation or metal on the surface of the substrate in order to control toner transportability and chargeability. Those with surface treatment such as plating, polishing, blasting, and coating with resin are used. Especially when using a sleeve from which metal such as aluminum, SUS, nickel, or ceramics is used, the effect of the present invention is remarkable. It becomes. The toner layer is formed on the developing roll by bringing an elastic blade into contact with the sleeve surface. A rubber elastic body such as silicone rubber or urethane rubber is preferably used as the material of the elastic blade, and an organic substance or an inorganic substance may be added and dispersed in the elastic body in order to control the toner charge amount.
[0041]
In the transfer step, the toner image on the latent image holding member is transferred to a transfer member (for example, paper). Examples of the transfer means in the present invention include known ones such as a contact type in which a transfer roller or a transfer belt is pressed against a latent image holding member, and a non-contact type using a corotron. The contact type is preferable in terms of prevention of occurrence.
[0042]
In the cleaning step, toner remaining on the latent image holding member without being transferred in the transfer step is removed by a cleaner. Examples of the cleaning means in the present invention include known means such as blade cleaning or roller cleaning. For blade cleaning, elastic rubber such as silicone rubber or urethane rubber is used.
In the fixing step, the toner image transferred to the transfer body is fixed by a fixing device. As the fixing means, a heat fixing method using a heat roll is generally used.
[0043]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the following description, “part” means “weight part” unless otherwise specified.
In this patent, a titanium oxide produced by a wet method, that is, a sulfuric acid method or a hydrochloric acid method is applied. The titanium compound used in the examples uses ilmenite as an ore, dissolves in sulfuric acid, and separates the iron content._FourIs hydrolyzed to TiO (OH)₂Wet precipitation method was used to produce
The key technologies in this adjustment are hydrolysis for nucleation, dispersion adjustment, and water washing. In particular, pH adjustment (acid neutralization) and slurry concentration adjustment in the dispersion process determine the primary particles of the titanium compound later. And requires a high level of control.
[0044]
(Adjustment of titanium compound A)
TiO (OH) produced by the above method₂To 100 parts, 40 parts by weight of isobutyltrimethoxysilane was mixed and reacted with heat. Then, after washing with water and filtering and drying at 120 ° C., soft aggregation is loosened with a pin mill, and the average particle size is 50 nm, resistance is 5.9 × 10.⁹A titanium compound A of Ω · cm was obtained.
(Adjustment of titanium compound B)
The average particle size is 30 nm and the resistance is 3.6 × 10, except that the pH adjustment and the dispersion adjustment are changed to adjust the particle size, and 50 parts by weight of isobutyltrimethoxysilane is mixed.⁸A titanium compound B of Ω · cm was obtained.
(Adjustment of titanium compound C)
Except for changing isobutyltrimethoxysilane to 40 parts of tetramethoxysilane, the same procedure as for external additive A was used. Average particle size 50 nm, resistance 4.2 × 10⁹A titanium compound C of Ω · cm was obtained.
[0045]
(Adjustment of titanium compound D)
Except for changing isobutyltrimethoxysilane to 40 parts of diphenyldichlorosilane, the average particle size is 30 nm and the resistance is 8.4 × 10, in the same manner as external additive B.^TenA titanium compound D of Ω · cm was obtained.
(Adjustment of titanium compound E)
The average particle size is 50 nm and the resistance is 2.4 × 10 6 in the same manner as the external additive A except that isobutyltrimethoxysilane is changed to 40 parts of decyltrimethoxysilane.^TenA titanium compound E of Ω · cm was obtained.
(Adjustment of titania particles F)
TiO (OH) adjusted by the above method₂After being washed with water, filtered and fired, the average particle size is 50 nm, and the resistance is 4.3 × 10.⁶An Ω · cm titanium oxide was obtained. Then, it grind | pulverized with the jet mill and the external additive F was obtained.
[0046]
(Adjustment of titania particles G)
Disperse external additive F in methanol, mix 40 parts by weight of isobutyltrimethoxysilane with 100 parts by weight of titania, wet pulverize with a sand grinder, remove the solvent while stirring with a kneader, dry and resist 5.4 × 10⁸An external additive G of Ω · cm was obtained.
(Adjustment of titania particles H)
TiO (OH) adjusted by the above method₂After being washed with water, filtered, and fired, titanium oxide having an average particle size of 30 nm was obtained. After that, it is dispersed again in water, wet pulverized with a sand grinder, then mixed with 50 weights of isobutyltrimethoxysilane in water, stirred and dried by heating, pulverized with a jet mill, and resistance 3.4. × 10⁸An external additive H of Ω · cm was obtained.
[0047]
Preparation of silica particles I
Dissolve 20 parts of dimethyl silicone oil in 300 parts of ethanol, stir and mix with 100 parts of silica fine particles having an average primary particle size of 12 nm, remove the ethanol using an evaporator, dry, and then crush the silica fine particles using a mortar. Sift through 105μm sieve and BET specific surface area 120m²/ G Silicone oil-treated silica particles I were prepared.
Adjustment of silica particles J
Dissolve 10 parts of dimethyl silicone oil in 300 parts of ethanol, stir and mix with 100 parts of silica fine particles having an average primary particle size of 60 nm, remove the ethanol using an evaporator, dry, and then crush the silica fine particles using a mortar. Sift through 105μm sieve and BET specific surface area 50m²/ G Silicone oil-treated silica particles J were prepared.
[0048]
Next, toner particles were produced. The particle size of the toner was measured with a particle size measuring device TAII manufactured by Coulter Counter and an aperture diameter of 100 μm.
<Manufacture of magnetic toner particles 1>

The above materials were mixed with a Henschel mixer and then melt kneaded with an extruder. After cooling, coarsely pulverized, finely pulverized by a jet mill, and further, this pulverized product was subjected to air classification to obtain a classified product having a volume average particle diameter D50 of 8.8 μm.
[0049]
<Production of non-magnetic toner particles 2>

The above materials were mixed with a Henschel mixer and then melt kneaded with an extruder. After cooling, coarsely pulverized, finely pulverized by a jet mill, and further, this pulverized product was classified by wind to obtain a classified product having a volume average particle diameter D50 of 9.2 μm.
[0050]
Example 1
To 100 parts of toner particles, silica particles I: 0.5 parts and titanium compound A: 1.0 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm, and developed. Agent 1 was obtained.
Example 2
To the toner particles 1: 100 parts, silica particles I: 0.5 parts and titanium compound B: 0.8 parts were externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm and developed. Agent 2 was obtained.
Example 3
Toner particles 1: 100 parts of silica particles J: 0.5 parts and titanium compound C: 1.0 parts were externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 3 was obtained.
[0051]
Example 4
Toner particle 1: To 100 parts, silica particles J: 0.5 part, titanium compound D: 0.8 part were externally added and mixed with a Henschel mixer, and further sieved with a wind sieving machine at 106 μm. Obtained.
Example 5
To the toner particles 1: 100 parts, silica particles I: 0.75 parts and titanium compound E: 1.0 parts were externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm and developed. Agent 5 was obtained.
[0052]
Comparative Example 1
Silica particles I: 0.5 parts and titania particles F: 1.0 parts are externally added and mixed with a Henschel mixer with respect to 1: 100 parts of toner particles, and further sieved at 106 μm with a wind sieving machine, and developed. Agent 6 was obtained.
Comparative Example 2
Silica particles I: 0.5 parts and titania particles G: 1.0 parts are externally added and mixed with a Henschel mixer with respect to 1: 100 parts of the toner particles, and further sieved at 106 μm with a wind sieving machine. Agent 7 was obtained.
Comparative Example 3
Silica particles J: 0.5 parts and titania particles H: 0.8 parts are externally added and mixed with a Henschel mixer with respect to 1: 100 parts of toner particles, and further sieved at 106 μm with a wind sieving machine, and developed. Agent 8 was obtained.
Comparative Example 4
To 100 parts of toner particles, 0.5 parts of hydrophobic silica R972 (Aerosil) and 0.8 parts of titania particles H are externally mixed using a Henschel mixer, and 106 μm using a further wind sieving machine. Sieving was performed to obtain developer 9.
[0053]
FIG. 1 shows an image forming apparatus used for image quality evaluation of a magnetic one-component developer.
After the latent image carrier 1 is charged by the roller charger 2, it is exposed to laser light to form an electrostatic latent image, and a urethane rubber layer forming blade is formed on the aluminum developer carrier 3 having a magnet inside. In step 4, the developer formed in a thin layer is developed without contact with the photoreceptor. The toner developed on the latent image holding member 1 is transferred to a transfer sheet by a contact type transfer roller 5 and thermally fixed by a fixing device 6. A blade type cleaner 7 was used to clean the residual toner on the latent image holding member. Here, the peripheral speed of the photosensitive member (latent image holding member) 1 is 100 mm / s, the peripheral speed of the developer carrier 3 is 150 mm / s, and the developer carrier 3 is subjected to static voltage by applying an AC voltage and a DC voltage. The electrostatic latent image was developed.
Using the image forming apparatus of FIG. 1, 10,000 sheets of the obtained developers 1 to 9 were printed in a high temperature and high humidity environment of 28 ° C. and 85% RH and in a low temperature and low humidity environment of 10 ° C. and 30% RH. Tested. The results are shown in Table 1.
[0054]
Example 6
To the toner particles 2: 100 parts, 1.3 parts of silica particles I and 1.0 parts of titanium compound A are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 10 was obtained.
Example 7
To toner particles 2: 100 parts, 1.3 parts of silica particles I and 0.8 parts of titanium compound B are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm to obtain developer 11. Obtained.
Example 8
To the toner particles 2: 100 parts, silica particles J: 1.5 parts and titanium compound A: 1.0 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 12 was obtained.
Example 9
To the toner particles 2: 100 parts, silica particles J: 1.5 parts and titanium compound C: 1.0 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 13 was obtained.
Example 10
To the toner particles 2: 100 parts, silica particles I: 1.3 parts and titanium compound E: 1.0 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 14 was obtained.
[0055]
Comparative Example 5
To the toner particles 2: 100 parts, silica particles I: 1.3 parts and titania particles F: 1.0 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 15 was obtained.
Comparative Example 6
To the toner particles 2: 100 parts, silica particles I: 1.3 parts and titania particles G: 1.0 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 16 was obtained.
Comparative Example 7
To the toner particles 2: 100 parts, silica particles I: 1.3 parts and titania particles H: 0.8 parts are externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm. 17 was obtained.
Comparative Example 8
To 100 parts of toner particles, 1.3 parts of hydrophobic silica R972 (manufactured by Aerosil Co., Ltd.) and 1.0 parts of titania particles G were externally added and mixed with a Henschel mixer, and further 106 μm with a wind sieving machine The developer 18 was obtained by sieving.
Comparative Example 9
With respect to 2: 100 parts of toner particles, 1.3 parts of silica particles I were externally added and mixed with a Henschel mixer, and further sieved with an air sieving machine at 106 μm to obtain developer 19.
[0056]
FIG. 2 shows an image forming apparatus used for image quality evaluation of a nonmagnetic one-component developer.
The latent image holder 1 is charged by a roller charger 2 and then exposed to a laser beam to form an electrostatic latent image. A thin layer is formed on an aluminum developer carrier 3 by a urethane rubber layer forming blade 4. Development is performed in a non-contact manner with the photoreceptor using the formed developer. Here, in order to stabilize toner conveyance, a developer supply roller 8 that rotates in the opposite direction to the developer carrier 3 is disposed in contact with the developer carrier 3. The toner developed on the latent image holding member 1 is transferred onto a transfer sheet by a contact type transfer roller 5 and thermally fixed by a fixing device 6. A blade type cleaner 7 was used to clean the residual toner on the latent image holding member. Here, the peripheral speed of the photosensitive member 1 is 100 mm / s, the peripheral speed of the developer carrier 3 is 170 mm / s, and the developer carrier 3 and the developer supply roller 5 are subjected to static voltage by applying an AC voltage and a DC voltage. The electrostatic latent image was developed.
Using the image forming apparatus of FIG. 2, 10,000 sheets of the obtained developers 10 to 19 were printed in a high temperature and high humidity environment of 28 ° C. and 85% RH and in a low temperature and low humidity environment of 10 ° C. and 30% RH. Tested. The results are shown in Table 2.
[0057]
<Toner fluidity>
The fluidity of the toner was evaluated using an offline auger dispenser. In the case of the amount of dispensation ≧ 700 mg / sec, it was evaluated as ◯, and otherwise.
<Charging environment difference>
The high-temperature high-humidity charge amount / low-temperature low-humidity charge amount was determined, and the case where the numerical value was 0.7 or more was evaluated as ◯, the case where it was 0.5 or more and less than 0.7 was evaluated as Δ, and the case where it was less than 0.5 was evaluated as ×.
[Charge amount of toner]
Using a blow-off charge measuring device manufactured by Toshiba Chemical Corporation, 30 g of 100 μm iron powder and 1.2 g of toner were measured after stirring for 60 seconds with a Turbula mixer. The measurement environment was a temperature of 22 ° C./humidity of 55% RH.
[0058]
[Specific gravity of titanium compound]
It measured based on JIS-K-0061 and 5-2-1 using a Le Chatelier specific gravity bottle. The operation is as follows.
Put about 250 ml of water into the Lecherteria specific gravity bottle, and adjust so that the meniscus is at the position of the scale. When the specific gravity bottle is immersed in a constant temperature water bath and the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy is 0.025 ml). About 100 g of a sample is weighed to the order of 1 mg, and its mass is defined as W. Place the weighed sample in a specific gravity bottle to remove bubbles. The specific gravity bottle is immersed in a constant temperature water bath, the liquid temperature is kept at 20.0 ± 0.2 ° C., and the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy is 0.025 ml).
The specific gravity is calculated by the following method.
D = W / (L₂-L₁)
S = D / 0.9982
here,
D: Sample density (20 ° C.) (g / cm^Three)
S: Specific gravity of the sample (20/20 ° C)
W: Apparent mass of sample (g)
L₁: Meniscus reading (20 ° C) (ml) before placing the sample in the density bottle
L₂: Reading of the meniscus after placing the sample in a specific gravity bottle (20 ° C.) (ml)
0.9982: density of water at 20 ° C. (g / cm^Three)
[0059]
<Fog>
The sensitivity was evaluated by observing the background with a 50 × magnifier. None, some, and some were evaluated as ◯, Δ, and X, respectively.
<Concentration maintenance>
Concentration measurement was performed with a concentration measuring device X-RITE 404A manufactured by X-RITE. ○ indicates 1.3 or more, Δ indicates less than 1.3, 1.1 or more, and x indicates less than 1.1.
<Sleeve streaks, image hollows, filming, toner scattering, ghost>
Each state was visually evaluated. None, some, and some were evaluated as ◯, Δ, and X, respectively.
[0060]
[Table 1]

[0061]
[Table 2]

[0062]
【The invention's effect】
As described above, the one-component developer of the present invention has such characteristics as chargeability, charging speed, environment dependency, charge distribution, toner charge retention on the developer carrier, sleeve contamination, photosensitive material scratches / contamination, etc. Since all the characteristics required for the one-component toner are satisfied, it is possible to obtain an excellent image quality that does not cause problems such as image density fluctuation, low developability, fogging, and image dropout image quality over a long period of time.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a preferred embodiment of a magnetic one-component developing device to which the present invention is applied.
FIG. 2 is a schematic configuration diagram showing a preferred embodiment of a non-magnetic one-component developing device to which the present invention is applied.
[Explanation of symbols]
1 Latent image carrier (photoreceptor)
2 Roller charger
3 Developer carrier
4 layer forming blade
5 Transfer roller
6 Fixing device
7 Cleaner

Claims (9)

In a one-component developer composed of toner particles containing a binder resin and a colorant and an additive, the additive is a titanium compound obtained by a reaction of TiO (OH) ₂ and a silane compound; A one-component developer comprising: silica treated with silicone oil or silicone varnish. _2. The one-component imaging agent according to claim 1, wherein the titanium compound is obtained by a reaction between TiO (OH) ₂ prepared by a wet method and a silane compound. The one-component system development according to claim 2, wherein the titanium compound is obtained by a reaction of 5 to 80 parts by weight of a silane compound with respect to 100 parts by weight of TiO (OH) ₂ prepared by a wet method. Agent. The weight ratio of the titanium compound and the silica treated with silicone oil or silicone varnish is 1: 0.2 to 1: 5, according to any one of claims 1 to 3 . One-component developer.   The one-component developer according to claim 1, wherein the toner particles are non-magnetic particles.   The one-component developer according to claim 1, wherein the toner particles are magnetic particles.   Image formation comprising a step of forming a latent image on a latent image carrier, a step of developing the latent image using a developer on a developer carrier, and a step of transferring the developed toner image onto a transfer member A method for forming an image, comprising using the one-component developer according to claim 1 as the developer. In an image forming method comprising a step of forming a latent image on a latent image carrier and a step of developing the latent image using a developer on the developer carrier, the developer carrier and the latent image carrier are The image forming method according to claim 7 , wherein the developing is performed in a non-contact state, and the one-component developer according to claim 1 is used as the developer. 9. The image forming method according to claim 8 , wherein in the transferring step, transfer is performed by bringing a transfer member into contact with the back surface of the transfer body.

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