JP3914646B2 - Toner for electrostatic charge development - Google Patents

Description

【０００９】
【数３】

【００１０】
【数４】

」、（２）「前記微粒子の体積固有抵抗が１×１０ ^８ 〜１×１０ ^１１ Ωｃｍの範囲であることを特徴とする前記（１）項に記載のトナー」、（３）「前記微粒子の含有率が０．１〜２重量％の範囲であることを特徴とする前記第（１）項に記載のトナー」により解決される。
【００１１】
以下、本発明を詳細に説明する。
即ち、必要十分な量の添加剤により被覆されたトナーにおいて、トナーの電気的特性のみならず、表面に存在する添加剤の電気的特性がトナー全体の帯電性に支配的影響を及ぼすことから、添加剤において適正な領域の誘電特性、及び電気抵抗特性を付与することが肝要である。特に複数種の添加剤を用い、異なる誘電特性の粒子を組み合わせて用いることにより、単体の添加剤にはない、際だった帯電の安定性が得られ、
【００１２】
【数５】

の関係にあるものは好ましく用いられる。この値が４を下回るとき、トナーはその表面層を低誘電体で被覆されるため、また、比誘電率差の少ないため添加剤相互の電荷の授受が乏しいためか、現像剤中のトナーの電荷量が徐々に上昇し、経時使用時に画像濃度の低下等の不具合を生ずることを見い出した。
【００１３】
一方で、この値が１６を上回るとき、現像剤中の帯電量が十分得られず、帯電量の保持能力が低いため、使用時において画像濃度の異常上昇や、地肌汚れなどの不具合を生ずる。さらに、転写性においてもトナー粒子の電荷保持能力が低いために好ましい結果を示さない。
【００１４】
また、少なくとも着色剤、結着樹脂、微粒子からなるトナーにおいて、微粒子の１ＫＨｚにおける交流法による比誘電率の測定値ε_βが下記一般式（ｂ）の関係を満たす粉体を混合してなるトナーであれば、際立った帯電特性を得られる。
【００１５】
【数６】

【００１７】
さらに、複数の添加剤を使用する場合においては、その混合物としての電気特性は重要であり、１ＫＨｚにおける交流法による比誘電率の測定値が２〜６の範囲であるときに好ましい画像を安定して得られる。また、この微粒子の体積固有抵抗が１×１０⁸〜１×１０¹¹Ωｃｍである場合に好ましい．
【００１８】
さらに、これらの微粒子の粒子径はトナーの粒径より十分に小さいことでトナーの流動性に効果が認められ、高い画像再現性を実現できる。そのときの添加剤の個数平均粒子径Ｄｎは１０〜５００ｎｍが好ましく用いられる。さらに、微粒子中に凝集体等の粗大粒子が混入するなど、広い粒径分布を持つときには画像上の抜け等の異常が発生するため、体積平均粒径をＤｖとするとき、Ｄｎ／Ｄｖの値が２．０以下であることが肝要である。また、これらの添加剤の含有量はトナー粒径５μｍ〜１０μｍのトナーにおいて、その流動性を十分に発現するためには該添加剤の含有量が０．１重量％〜２重量％の比率で含有されていることが好ましい。
トナー粒径が５μｍより小さいとき、必要な流動性を得るために要する添加剤の含有率はさらに増加するが、一方で定着性の低下や感光体の損傷等の不具合も発生しやすい。また、トナー粒径１０μｍ以上では一般に添加剤の必要な含有率は低下するが、画像の精細性に欠ける。
【００１９】
用いる添加剤としては前記のとおり、従来公知の金属酸化物微粒子の疎水化物において流動性に優れたものが見い出されるが、特に疎水性酸化チタン微粒子表面が下記一般式の化学構造を有する化合物及びその縮合物により表面が疎水化処理され、実質的に被覆されている場合には、
【００２０】
【化３】

誘電特性と流動性を両立するに有効である。具体的には、トリメトキシパーフルオロプロピルシランにより表面を疎水化処理された酸化チタンやトリメトキシパーフルオロプロピルシラン及びメチルトリメトキシシランの混合物で疎水化処理された酸化チタン等である。
【００２１】
本発明に使用されるトナーとしては一般公知の粉砕法、重合法等の各種のトナー製法により作成されたトナーを用いることができ、このようなトナーはバインダー樹脂としての熱可塑性樹脂を主成分とし、着色剤、微粒子、帯電制御剤、離型剤等を含むものである。
【００２２】
本発明に使用されるバインダー樹脂としては、アクリル系としては、ポリスチレン、ポリビニルトルエン等のスチレン及びその置換体の単重合体、スチレン−ｐ−クロルスチレン共重合体、スチレン−プロピレン共重合体、スチレン−ビニルトルエン共重合体、スチレン−アクリル酸メチル共重合体、スチレン−アクリル酸エチル共重合体、スチレン−アクリル酸ブチル共重合体、スチレン−メタアクリル酸メチル共重合体、スチレン−メタアクリル酸エチル共重合体、スチレン−メタアクリル酸ブチル共重合体、スチレン−α−クロルメタアクリル酸メチル共重合体、スチレン−アクリロニトリル共重合体、スチレン−ビニルメチルエーテル共重合体、スチレン−ビニルメチルケトン共重合体、スチレン−ブタジエン共重合体、スチレン−イソプレン共重合体、スチレン−マレイン酸共重合体、スチレン−マレイン酸エステル共重合体等のスチレン系共重合体、ポリメチルメタクリレート、ポリブチルメタクリレート、ポリ塩化ビニル、ポリ酢酸ビニル、ポリエチレン、ポリプロピレン、ポリエステル、ポリウレタン、エポキシ樹脂、ポリビニルブチラール、ポリアクリル酸樹脂、ロジン、変性ロジン、テルペン樹脂、フェノール樹脂、脂肪族または脂肪族炭化水素樹脂、芳香族系石油樹脂、塩素化パラフィン、パラフィンワックスなどが単独あるいは混合して使用できる。
【００２３】
ポリエステル樹脂としては、アルコールと酸との重縮合反応によって得られ、例えばアルコールとしては、ポリエチレングリコール、ジエチレングリコール、トリエチレングリコール、１，２−プロピレングリコール、１，３−プロピレングリコール、１，４−プロピレングリコール、ネオペンチルグリコール、１，４−ブテンジオールなどのジオール類、１，４−ビス（ヒドロキシメチル）シクロヘキサン、ビスフェノールＡ、水素添加ビスフェノールＡ、ポリオキシエチレン化ビスフェノールＡ、ポリオキシプロピレン化ビスフェノーＡなどのエーテル化ビスフェノール類、これらを炭素数３〜２２の飽和もしくは不飽和の炭化水素基で置換した２価のアルコール単位体、その他の２価のアルコール単位体、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−ソルビタン、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、蔗糖、１，２，４−ブタントリオール、１，２，５−ペンタントリオール、グリセロール、２−メチルプロパントリオール、２−メチル−１，２，４−ブタントリオール、トリメチロールエタン、トリメチロールプロパン、１，３，５−トリヒドロキシメチルベンゼン等の三価以上の高アルコール単量体を挙げることができる。
【００２４】
また、ポリエステル樹脂を得るために用いられるカルボン酸としては、例えばパルミチン酸、ステアリン酸、オレイン酸等のモノカルボン酸、マレイン酸、フマール酸、メサコン酸、シトラコン酸、テレフタル酸、シクロヘキサンジカルボン酸、コハク酸、アジピン酸、セバチン酸、マロン酸、これらを炭素数３〜２２の飽和もしくは不飽和の炭化水素基で置換した２価の有機酸単量体、これらの酸の無水物、低級アルキルエステルとリノレイン酸からの二量体、１，２，４−ベンゼントリカルボン酸、１，２，５−ベンゼントリカルボン酸、２，５，７−ナフタレントリカルボン酸、１，２，４−ナフタレントリカルボン酸、１，２，４−ブタントリカルボン酸、１，２，５−ヘキサントリカルボン酸、１，３−ジカルボキシル−２−メチル−２−メチレンカルボキシプロパン、テトラ（メチレンカルボキシル）メタン、これらの酸の無水物等の三価以上の多価カルボン酸単量体を挙げることができる。
【００２５】
さらにまた、本発明で使用されるエポキシ樹脂としては、ビスフェノールＡとエポクロルヒドリンとの重縮合物等があり、例えば、エポミックＲ３６２、Ｒ３６４、Ｒ３６５、Ｒ３６６、Ｒ３６７、Ｒ３６９（以上三井石油化学工業（株）製）、エポトートＹＤ−０１１、ＹＤ−０１２、ＹＤ−０１４、ＹＤ−９０４、ＹＤ−０１７、（以上東都化成（株）製）エポコ−ト１００２、１００４、１００７（以上シェル化学社製）等の市販のものがある。
【００２６】
本発明に使用される着色剤としては、カーボンブラック、ランプブラック、鉄黒、群青、ニグロシン染料、アニリンブルー、フタロシアニンブルー、ハンザイエローＧ、ローダミン６Ｇ、レーキ、カルコオイルブルー、クロムイエロー、キナクリドン、ベンジジンイエロー、ローズベンガル、トリアリルメタン系染料、モノアゾ系、ジスアゾ系、染顔料など、従来公知のいかなる染顔料をも単独あるいは混合して使用し得る。
【００２７】
また、トナーは通常使用されるトナーと同様に摩擦帯電性を制御する目的で含有せしめる薬剤を含有していてもなんら不都合はない。そうした、いわゆる極性制御剤としては、例えばモノアゾ染料の金属錯塩、ニトロフミン酸およびその塩、サリチル酸、ナフトエ塩、ジカルボン酸のＣｏ、Ｃｒ、Ｆｅ等の金属錯体アミノ化合物、第４級アンモニウム化合物、有機染料などがある。
【００２８】
さらにまた、本発明のトナーは必要に応じて離型剤を添加してもよい。本発明で使用される離型材料としては、低分子量ポリプロピレン、低分子量ポリエチレン、カルナウバワックス、マイクロクリスタリンワックス、ホホバワックス、ライスワックス、モンタン酸ワックス等を単独または混合して用いることができるが、これらに限定されるものではない。トナー全体に占める割合は、結着樹脂が７５％〜９３％、着色剤が３％〜１０％、微粒子は０．１％〜３％、その他の成分は１％〜７％である。
【００２９】
本発明のトナーは、キャリアを用いない一成分現像剤や二成分系乾式現像剤としてキャリア粉と混合して用いられる。本発明に使用し得るキャリアとしては、公知のものがすべて使用可能であり、例えば鉄粉、フェライト粉、ニッケル粉のごとき磁性を有する粉体、ガラスビーズ等およびこれらの表面を樹脂などで処理したもの（例えばシリコーン樹脂で被覆したもの）などが挙げられる。シリコーン樹脂としては従来より知られるいずれのシリコーン樹脂であってもよい。シリコーン樹脂層の形成方法としては従来同様、キャリア核体粒子の表面に噴霧法、浸漬法などの手段でシリコーン樹脂を塗布すればよい。シリコーン樹脂溶液中に添加物を含有させることも可能であり、例えば導電性微粉末や帯電制御性薬剤として先に列記したごとき顔料、染料、磁性材料、導電性材料など無機物、有機物をそれぞれすべて単独もしくは混合して添加することができる。
【００３０】
さらにシリコーン樹脂と添加物の分散性、相溶性を向上させるために、一般公知のシランカップリング剤を含めることができる。シランカップリング剤としては、
【００３１】
【化４】
Ｘ−Ｓｉ（ＯＲ）ｎ ・・・一般式（II)
（式中、ｎは１〜３の整数である。）
一般式（II）で表わされるすべての物質を意味し、Ｘは有機物、無機物との反応性、吸着性を有する各種の官能基、および官能基を有する飽和、不飽和の炭化水素鎖を意味する。ＯＲはアルコキシ基を意味する。
特にＸにアミノ基を有する、いわゆるアミノシランカップリング剤は好ましく用いられる。トナーとキャリアの混合割合は、トナーとキャリアの平均粒径や比重にもよるが、一般にキャリア１００重量部に対し、トナー０．５〜１５．０重量部程度が適当である。
【００３２】
【実施例】
以下、本発明を実施例を用いてさらに具体的に説明するが、これら実施例は本発明の一態様にすぎず、本発明はこれら実施例に制限されない。また、本実施例においては、二種類の微粒子についての態様を示しているが、三種類やそれ以上の微粒子を添加することも可能である。なお、以下実施例に示す各成分量（部）はいずれも重量基準である。粒子径の測定はコールター社製コールターカウンタにより測定した。
《トナー母粒子１の製造例》
以下の方法でトナー１を得た。
ポリエステル樹脂 ７０部
スチレンアクリル樹脂 １５部
カルナウバワックス ５部
カーボンブラック １０部
サリチル酸誘電体金属塩 ３部
以上の物質をブレンダーにて十分に混合した後、２軸式押出し機にて溶融混練し、放冷後カッターミルで粗粉砕し、ついでジェット気流式微粉砕機で微粉砕し、さらに風力分級機で体積平均粒径１２．０μｍのトナー母粒子１を得た。
【００３３】
《トナー母粒子２の製造例》
上記製造例と同様に作成した粗粉砕粒子をジェット気流式粉砕機で微粉砕し、さらに風力分級機で分級し、体積平均粒径８．２μｍのトナー母粒子２を得た。
【００３４】
《流動性改質剤微粒子の製造例》
作成する芯材とする微粒子ａの１００部を各種表面処理剤ｂの処方量をトルエンに溶解した溶液に分散しスラリーを作成した後、ボールミル分散機に入れ、約２４時間混合分散する。その後、十分な撹拌、専断を加えながら減圧乾燥を行ない、得られた粉体を１００〜３００℃の高温下で焼成し、冷却後、粉砕機で粉砕し、微粉体１〜５を得た。
各微粒子の比誘電率は以下のようにして求めた。
各微粒子を、不導体の円筒の上下に良好な導電性の金属電極を有する内径約２ｃｍの測定セル内に０．５ｍｍ〜１．０ｍｍの厚みになるように充填した。交流ブリッジ法により２５℃、大気中、室内において測定し、１ＫＨｚの測定周波数から各微粒子の比誘電率を求めた。各微粒子の詳細は表１に示す。
【００３５】
【表１】

【００３６】
《トナーの製造例》
トナー母粒子１の１００部に対し、表１における微粒子を表２の処方量にて添加し、ヘンシェルミキサーにて一定時間の撹拌を行ない、得られた粉体を目開き２００μｍのメッシュにより篩い、粗大粒子を取り除いてトナーを得た。それぞれのトナーの詳細は表２に示す。特にトナー６〜１１においては、用いる流動性改質剤微粒子を篩がけし、粗大粒子を除去した後に使用した。
【００３７】
また、無機微粒子の評価は以下のように行なった。結果は表２に併記する。
粒子径測定：トナー適当量をメタノール、水の等量混合液に投入し、緩やかに撹拌を行なう。必要に応じて適宜ＰＨ調整を行なった後、上澄み液を採取する。この分散液を大塚電子（株）製ＤＬＳ７００にて動的光散乱測定を行ない、ＣＵＭＬＡＮＴ法により粒子径を決定する。
比誘電率および体積固有抵抗：微粒子を、不導体の円筒の上下に良好な導電性の金属電極を有する内径約２ｃｍの測定セル内に０．５ｍｍ〜１．０ｍｍの厚みになるように充填した。交流ブリッジ法により２５℃、大気中、室内において測定し、１ＫＨｚの測定周波数における微粒子の比誘電率を求めた。
【００３８】
【数７】

の値を求める。
【００３９】
【表２】

【００４０】
実施例、参考例及び比較例
製造例で作成したトナー５部をリコー製シリコンコートキャリア１００部と混合し、リコー製ｉｍａｇｉｏ ＭＦ２００に装填して画像面積率６％の文字画像チャートで１万枚のランニング評価を行なった。
ランニングの経時において、逐次画像の評価を次のように行なった。
・細線再現性：主走査、副走査方向ともに６００ｄｏｔ／ｉｎｃｈ、１５０ｌｉｎｅ／ｉｎｃｈのドット格子ライン画像を出力し、ライン画像の切れ、かすれを３段階で目視評価した。
◎：大変良好
○：良好
△：若干不良
Ｘ：不良（許容不可のレベル）
・解像力：主走査、副走査方向ともに６００ｄｏｔ／ｉｎｃｈ、１５０ｌｉｎｅ／ｉｎｃｈの１ドット独立網点画像を出力し、ドット抜け、画像濃度ムラを３段階で目視評価した。
◎：大変良好
○：良好
△：若干不良
Ｘ：不良（許容不可のレベル）
・転写性：画像面積率６％の文字画像を出力し、文字部の転写抜けを３段階で目視評価した。
◎：大変良好
○：良好
△：若干不良
Ｘ：不良（許容不可のレベル）
また、現像部から現像剤を取り出し、トナーの帯電量を測定した。帯電量の測定は一般公知のブローオフ法によった。画像濃度はマクベス反射濃度計により測定した。評価の結果を表３に示す。
【００４１】
【表３】

【００４２】
【発明の効果】
以上、詳細かつ具体的な説明により明らかなように、本発明によって、経時使用にも安定し、解像性に富む高濃度の画像が得られ、また、転写性に優れた良好な画像を永続的に再現する静電荷現像用トナーが提供されるという極めて優れた効果を発揮する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic image developing toner used in electrophotography, electrostatic printing, and the like.
[0002]
[Prior art]
In general, in an electrophotographic method based on the Carlson process, or an electrostatic recording method or the like, in order to develop an electrostatic latent image formed on a latent image carrier made of a photoconductive photoreceptor or dielectric, There are two main methods. One is a two-component development system in which a desired charge amount is imparted to a toner using a mixture of toner and carrier as disclosed in JP-A-61-147261, and the other is a development sleeve in which toner is used alone. This is a one-component developing system in which a toner is charged by a blade on an equal toner supply roller. As the toner used in this way, it is common to use a fine powder in which a synthetic or natural thermoplastic resin is the main component and a colorant such as carbon or other dyes is dispersed and contained. In order to stably carry out appropriate electrostatic charge development over a long period of time, studies have been made to contain various chemicals.
[0003]
In so-called two-component development in which a carrier and toner are mixed and a toner is given a desired charge amount for development, it is desirable that the charge amounts of the toner and developer always show stable values over time of use. Needless to say, from the viewpoints of image stability and reliability. In particular, the charge amount of a normal toner is balanced by the chargeability of the toner and the ability to hold the generated charge because the toner which is substantially a dielectric is charged by friction and contact. It is known that the charge amount has a considerable influence on the characteristics. The ratio of the surface area to the toner volume is generally inversely proportional to the toner particle size, and the required amount of chargeability and fluidity improving agent varies depending on the size of the toner surface area ratio. There is a distribution, and the consumption over time varies depending on the particle size, and the change in particle size distribution over time also occurs for fluidity improvers, so the change in charge amount and fluidity after use over time. It becomes difficult to prevent.
[0004]
On the other hand, in order to obtain a recent high-definition and high-reproducibility image, the toner must have a higher fluidity than conventional ones. As shown in JP-A Nos. 52-30437 and 60-238847, hydrophobicity is required. Although a method of adding fine powders is widely used, the addition of these fine powders is not necessarily sufficient for charging stability. In particular, with the recent reduction in toner particle diameter, the amount of flowability modifier added to the toner tends to increase.
[0005]
In addition, as seen in Japanese Patent Application Laid-Open No. 59-46664, an image carrier such as a photoconductor and a transfer material such as transfer paper are directly brought into contact with a transfer material without using a conventional corona charging method. The method of providing a potential difference between the image carrier and the transfer material by the electrode to transfer the toner by the potential difference and the pressure is preferably used because it does not generate ozone as compared with the conventional method. By using the transfer method, there is a problem that a partial transfer failure occurs inside the fine line of the transfer image. Although this can be avoided to some extent by improving the fluidity of the toner, a large amount of additive is inevitably required for this purpose. The necessity of an increase in the amount of additive in the toner has an influence on the stability of the toner charge amount over time, and problems such as a decrease in image density due to an increase in the developer charge amount during use have occurred. Examples of toners characterized by such additives include, for example, oxidation treated with a surface treatment using a hydrophobizing agent such as silane, silica, or silicone compound in JP-A-7-56380 and JP-A-7-230179. Although a method using titanium is disclosed, these surface-treated titanium oxide particles cannot be said to have sufficient fluidity modifying ability as compared with hydrophobic silica and the like, and the above-mentioned transfer failure cannot be improved. . Further, due to the conductivity and high dielectric property of the base material, there are problems such as causing a decrease in chargeability depending on the state of the surface treatment.
[0006]
[Problems to be solved by the invention]
A first object of the present invention is to provide a toner that maintains the chargeability of the toner, particularly stable chargeability over time, has a high density, and has little fluctuation in image density. The second problem is to provide a toner with high fine line reproducibility and high resolution, and the third problem is to provide a good image with no transfer omission.
[0007]
The above-described problem is (1) “a toner comprising at least a colorant, a binder resin, and fine particles, wherein the fine particles are a mixture of hydrophobic titanium oxide fine particles and hydrophobic silica fine particles, and the surface of the hydrophobic titanium oxide fine particles. Is substantially covered with a compound having the chemical structure of the following general formula (I) and / or a condensate thereof, and the measured value of the relative dielectric constant of each fine particle by the alternating current method at 1 KHz is represented by the following general formula (a) of satisfying the relationship, further toner, wherein the measured value of the dielectric constant by the AC method at 1KHz of the two particulate mixture satisfies the following formula (b) epsilon _beta is 2-6.
[0008]
[Chemical 2]

[0009]
[Equation 3]

[0010]
[Expression 4]

(2) “ The toner according to (1) above, wherein the specific volume resistivity of the fine particles is in the range of 1 × 10 ⁸ to 1 × 10 ¹¹ Ωcm”, (3) “ The problem is solved by the toner according to item (1), wherein the content is in the range of 0.1 to 2% by weight .
[0011]
Hereinafter, the present invention will be described in detail.
That is, in the toner coated with a necessary and sufficient amount of additive, not only the electrical characteristics of the toner but also the electrical characteristics of the additive present on the surface has a dominant influence on the charging property of the whole toner. It is important to provide dielectric properties and electric resistance characteristics in an appropriate region in the additive. In particular, by using multiple types of additives and combining particles with different dielectric properties, outstanding charge stability that is not found in a single additive can be obtained.
[0012]
[Equation 5]

Those having the relationship are preferably used. When this value is less than 4, the surface layer of the toner is coated with a low dielectric material, and because the difference in relative permittivity is small, the charge transfer between the additives is poor. It has been found that the amount of charge gradually increases and causes problems such as a decrease in image density when used over time.
[0013]
On the other hand, when this value exceeds 16, the charge amount in the developer cannot be obtained sufficiently, and the ability to hold the charge amount is low, so that problems such as abnormal increase in image density and background contamination occur during use. Further, in terms of transferability, the toner particles have a low charge retention capability, and therefore do not show preferable results.
[0014]
Further, a toner comprising at least a colorant, a binder resin, and fine particles, and a powder in which the measured value ε _β of the specific dielectric constant of the fine particles by the alternating current method at 1 KHz satisfies the relationship of the following general formula (b) If so, outstanding charging characteristics can be obtained.
[0015]
[Formula 6]

[0017]
Furthermore, when a plurality of additives are used, the electrical characteristics of the mixture are important, and a preferable image is stabilized when the measured value of the relative dielectric constant by the AC method at 1 KHz is in the range of 2-6. Obtained. Moreover, it is preferable when the volume resistivity of the fine particles is 1 × 10 ⁸ to 1 × 10 ¹¹ Ωcm.
[0018]
Further, since the particle diameter of these fine particles is sufficiently smaller than the particle diameter of the toner, an effect on the fluidity of the toner is recognized, and high image reproducibility can be realized. The number average particle diameter Dn of the additive at that time is preferably 10 to 500 nm. Further, when the particle size has a wide particle size distribution such as coarse particles such as aggregates mixed in the fine particles, abnormalities such as omission on the image occur. Therefore, when the volume average particle size is Dv, the value of Dn / Dv Is important to be 2.0 or less. Further, the content of these additives is a ratio of 0.1% by weight to 2% by weight for the toner having a particle diameter of 5 μm to 10 μm in order to sufficiently exhibit the fluidity. It is preferably contained.
When the toner particle size is smaller than 5 μm, the content of the additive required for obtaining the required fluidity further increases, but on the other hand, problems such as a decrease in fixing property and damage to the photoreceptor tend to occur. Further, when the toner particle size is 10 μm or more, the necessary content of additives generally decreases, but the image definition is poor.
[0019]
As described above, as the additive to be used, a conventionally known hydrophobized metal oxide fine particle having excellent fluidity is found, and in particular, a compound having a chemical structure of the following general formula and its hydrophobic titanium oxide fine particle surface and its compound When the surface is hydrophobized by the condensate and is substantially covered,
[0020]
[Chemical 3]

It is effective to achieve both dielectric properties and fluidity. Specifically, a titanium oxide having hydrophobicized with a mixture of trimethoxy perfluoropropyl silane titanium oxide or trimethoxy perfluoropropyl surface was hydrophobized with a silane and methyl trimethoxy silane.
[0021]
As the toner used in the present invention, a toner prepared by various toner production methods such as a generally known pulverization method and polymerization method can be used, and such a toner is mainly composed of a thermoplastic resin as a binder resin. , Colorants, fine particles, charge control agents, release agents and the like.
[0022]
As the binder resin used in the present invention, acrylics include styrene such as polystyrene and polyvinyltoluene, and homopolymers of substituted styrene, styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene. -Vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate Copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylate methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer Polymer, styrene-butadiene copolymer, styrene Soprene copolymer, styrene copolymer such as styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester , Polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or aliphatic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. alone or Can be mixed and used.
[0023]
The polyester resin is obtained by a polycondensation reaction between an alcohol and an acid. For example, the alcohol includes polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene. Diols such as glycol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, etc. Etheric bisphenols, divalent alcohol units in which these are substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, other divalent alcohol units, sorbitol, 1,2,3, -Hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, Examples thereof include trihydric or higher alcohol monomers such as 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene.
[0024]
Examples of the carboxylic acid used to obtain the polyester resin include monocarboxylic acids such as palmitic acid, stearic acid, and oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. Acids, adipic acid, sebacic acid, malonic acid, divalent organic acid monomers in which these are substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, anhydrides of these acids, lower alkyl esters and Dimer from linolenic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1, 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl 2-methylene carboxy propane, tetra (methylene carboxyl) methane, can be mentioned trivalent or higher polycarboxylic acid monomers of anhydrides of these acids.
[0025]
Furthermore, the epoxy resin used in the present invention includes a polycondensate of bisphenol A and epochrohydrin. For example, Epomic R362, R364, R365, R366, R367, R369 (Mitsui Petrochemical Industries, Ltd.) Epototo YD-011, YD-012, YD-014, YD-904, YD-017 (above Toto Kasei) Epocote 1002, 1004, 1007 (above Shell Chemical Co., Ltd.) ) And other commercially available products.
[0026]
Examples of the colorant used in the present invention include carbon black, lamp black, iron black, ultramarine, nigrosine dye, aniline blue, phthalocyanine blue, Hansa Yellow G, rhodamine 6G, lake, calco oil blue, chrome yellow, quinacridone, and benzidine. Any conventionally known dyes such as yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, and dyes can be used alone or in combination.
[0027]
Further, the toner does not have any inconvenience even if it contains an agent to be contained for the purpose of controlling the triboelectric chargeability in the same manner as the toner that is usually used. Such so-called polarity control agents include, for example, metal complex salts of monoazo dyes, nitrohumic acid and salts thereof, salicylic acid, naphthoic salts, metal complexes of dicarboxylic acids such as Co, Cr, Fe, etc., quaternary ammonium compounds, organic dyes and so on.
[0028]
Furthermore, a release agent may be added to the toner of the present invention as necessary. As the release material used in the present invention, low molecular weight polypropylene, low molecular weight polyethylene, carnauba wax, microcrystalline wax, jojoba wax, rice wax, montanic acid wax and the like can be used alone or in combination. It is not limited to these. The proportion of the total toner is 75% to 93% for the binder resin, 3% to 10% for the colorant, 0.1% to 3% for the fine particles, and 1% to 7% for the other components.
[0029]
The toner of the present invention is used as a one-component developer not using a carrier or a two-component dry developer mixed with carrier powder. As the carrier that can be used in the present invention, any known carrier can be used. For example, magnetic powder such as iron powder, ferrite powder, nickel powder, glass beads, and the like, and their surfaces are treated with a resin or the like. And the like (for example, those coated with a silicone resin). Any conventionally known silicone resin may be used as the silicone resin. As a conventional method for forming the silicone resin layer, the silicone resin may be applied to the surface of the carrier core particles by means of spraying, dipping, or the like. It is also possible to add an additive to the silicone resin solution. For example, pigments, dyes, magnetic materials, conductive materials such as conductive fine powders and charge control agents listed above, and inorganic materials and organic materials are all individually used. Or it can mix and add.
[0030]
Furthermore, in order to improve the dispersibility and compatibility of the silicone resin and the additive, a generally known silane coupling agent can be included. As a silane coupling agent,
[0031]
[Formula 4]
X-Si (OR) n ... General formula (II)
(In the formula, n is an integer of 1 to 3.)
It means all substances represented by the general formula (II), and X means various functional groups having reactivity and adsorptivity with organic and inorganic substances, and saturated and unsaturated hydrocarbon chains having functional groups. . OR means an alkoxy group.
In particular, a so-called aminosilane coupling agent having an amino group in X is preferably used. The mixing ratio of the toner and the carrier depends on the average particle diameter and specific gravity of the toner and the carrier, but is generally about 0.5 to 15.0 parts by weight with respect to 100 parts by weight of the carrier.
[0032]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example, these Examples are only one aspect | mode of this invention, and this invention is not restrict | limited to these Examples. Further, in the present embodiment, an embodiment of two types of fine particles is shown, but three or more types of fine particles can be added. In addition, each component amount (part) shown in the following examples is based on weight. The particle size was measured with a Coulter counter manufactured by Coulter.
<< Production Example of Toner Base Particle 1 >>
Toner 1 was obtained by the following method.
Polyester resin 70 parts Styrene acrylic resin 15 parts Carnauba wax 5 parts Carbon black 10 parts Salicylic acid dielectric metal salt 3 parts or more of the materials are thoroughly mixed in a blender, melted and kneaded in a twin-screw extruder, and released. After cooling, coarsely pulverized by a cutter mill, then finely pulverized by a jet airflow fine pulverizer, and further toner base particles 1 having a volume average particle diameter of 12.0 μm were obtained by an air classifier.
[0033]
<< Production Example of Toner Base Particle 2 >>
The coarsely pulverized particles prepared in the same manner as in the above production example were finely pulverized with a jet airflow pulverizer and further classified with an air classifier to obtain toner base particles 2 having a volume average particle diameter of 8.2 μm.
[0034]
<Production example of fluidity modifier fine particles>
100 parts of the fine particles a as the core material to be prepared are dispersed in a solution in which the prescribed amounts of various surface treatment agents b are dissolved in toluene to prepare a slurry, which is then placed in a ball mill disperser and mixed and dispersed for about 24 hours. Thereafter, drying under reduced pressure was performed while adding sufficient stirring and dedication, and the obtained powder was fired at a high temperature of 100 to 300 ° C., cooled, and pulverized with a pulverizer to obtain fine powders 1 to 5.
The relative dielectric constant of each fine particle was determined as follows.
Each fine particle was filled to a thickness of 0.5 mm to 1.0 mm in a measuring cell having an inner diameter of about 2 cm and having a good conductive metal electrode above and below a non-conductive cylinder. Measurement was performed at 25 ° C. in the air and indoors by the AC bridge method, and the relative dielectric constant of each fine particle was determined from the measurement frequency of 1 KHz. Details of each fine particle are shown in Table 1.
[0035]
[Table 1]

[0036]
<Example of toner production>
To 100 parts of the toner base particles 1, the fine particles in Table 1 are added in the prescribed amounts shown in Table 2, the mixture is stirred for a certain time with a Henschel mixer, and the obtained powder is sieved with a mesh having an opening of 200 μm. Coarse particles were removed to obtain a toner. Details of each toner are shown in Table 2. In particular, toners 6 to 11 were used after the fluidity modifier fine particles to be used were sieved to remove coarse particles.
[0037]
The inorganic fine particles were evaluated as follows. The results are also shown in Table 2.
Particle size measurement: An appropriate amount of toner is put into an equal volume of methanol and water and gently stirred. After adjusting the pH as necessary, collect the supernatant. The dispersion is subjected to dynamic light scattering measurement using DLS700 manufactured by Otsuka Electronics Co., Ltd., and the particle size is determined by the CUMLANT method.
Relative permittivity and volume resistivity: Fine particles were filled in a measuring cell having an inner diameter of about 2 cm having a good conductive metal electrode above and below a non-conducting cylinder so as to have a thickness of 0.5 mm to 1.0 mm. . Measurement was performed at 25 ° C. in the air and indoors by an AC bridge method, and the relative dielectric constant of the fine particles at a measurement frequency of 1 KHz was obtained.
[0038]
[Expression 7]

Find the value of.
[0039]
[Table 2]

[0040]
Examples, reference examples and comparative examples
5 parts of the toner prepared in the production example was mixed with 100 parts of Ricoh's silicon-coated carrier, loaded into Ricoh's imagio MF200, and 10,000 running evaluations were performed using a character image chart with an image area ratio of 6%.
As the running time elapses, the images were sequentially evaluated as follows.
Fine line reproducibility: A dot grid line image of 600 dots / inch and 150 lines / inch was output in both the main scanning direction and the sub-scanning direction, and the cut and blur of the line image were visually evaluated in three stages.
◎: Very good ○: Good △: Somewhat bad X: Bad (unacceptable level)
Resolution: A one-dot independent halftone dot image of 600 dots / inch and 150 line / inch was output in both the main scanning and sub-scanning directions, and dot omission and image density unevenness were visually evaluated in three stages.
◎: Very good ○: Good △: Somewhat bad X: Bad (unacceptable level)
Transferability: A character image with an image area ratio of 6% was output, and the missing transfer of the character portion was visually evaluated in three stages.
◎: Very good ○: Good △: Somewhat bad X: Bad (unacceptable level)
Further, the developer was taken out from the developing portion, and the charge amount of the toner was measured. The charge amount was measured by a generally known blow-off method. The image density was measured with a Macbeth reflection densitometer. Table 3 shows the evaluation results.
[0041]
[Table 3]

[0042]
【The invention's effect】
As described above, as is clear from the detailed and specific description, the present invention provides a high-density image that is stable over time, has high resolution, and is excellent in transferability. The electrostatic charge developing toner that is reproduced in a realistic manner can be provided.

Claims (3)

In a toner comprising at least a colorant, a binder resin, and fine particles, the fine particles are a mixture of hydrophobic titanium oxide fine particles and hydrophobic silica fine particles, and the surface of the hydrophobic titanium oxide fine particles has a chemical structure represented by the following general formula (I) The measured value of the relative dielectric constant by the alternating current method at 1 KHz of each fine particle satisfies the relationship of the following general formula (a), and is further covered with the following general formula (a): toner, wherein the measured value of the dielectric constant by the AC method at 1KHz of the two particulate mixture satisfies the relationship b) epsilon _beta is 2-6.

The toner according to claim 1, wherein the volume resistivity of the fine particles is in the range of 1 × 10 ⁸ to 1 × 10 ¹¹ Ωcm.   The toner according to claim 1, wherein the content of the fine particles is in the range of 0.1 to 2% by weight.