JP3647253B2 - Developing device, developer carrier and developing method - Google Patents

Description

（式中のＲ₁、Ｒ₂、Ｒ₃、Ｒ₄は、夫々置換基を有してもよいアルキル基、置換基を有してもよいアリール基、アルアルキル基を表わし、Ｒ₁〜Ｒ₄は夫々同一でも或いは異なっていてもよい。Ｘ^-は、酸の陰イオンを表わす。）
上記の一般式において、Ｘ^-の酸イオンの具体例としては、有機硫酸イオン、有機スルホン酸イオン、有機リン酸イオン、モリブデン酸イオン、タングステン酸イオン、モリブデン原子或いはタングステン原子を含むヘテロポリ酸等が挙げられる。
【００１３】
これに対し、例えば、下記式で表わされるような、それ自身が鉄粉に対して負帯電性を有する含フッ素第４級アンモニウム塩化合物についても検討を行ったが、該化合物の添加によっては本発明の所期の目的が達成されないことがわかった。即ち、下記式で表される化合物は、電子吸引性の強いフッ素原子が構造中にあるので、それ自身が鉄粉に対して負帯電性を有するが、本発明の場合と同様に、該化合物をフェノール樹脂中に分散させた樹脂組成物を結着樹脂とし、これを加熱硬化させて現像剤担持体上の被覆層を形成しても、それ自身が鉄粉に対して正帯電性である第４級アンモニウム塩化合物を含有させたフェノール樹脂を結着樹脂に用いる本発明の場合ほどには、正帯電性の現像剤に対する高い正摩擦帯電付与性は得られなかった。
【００１４】
【化２】

【００１５】
又、被覆層の形成に用いられる被膜形成材料であるフェノール樹脂の正帯電性現像剤に対する正帯電付与性を向上させる添加剤としては、本発明で使用する自身が鉄粉に対して正帯電性である第４級アンモニウム塩化合物以外のものとしては、例えば、ネガ性シリカ或はネガ性テフロン等の粒子も考えられるが、この場合には、所望の正帯電付与性を得るにはこれらを大量に添加する必要があり、被覆層としての強度低下を招き易い。又、負帯電制御剤であるクロルフェノールを含むアゾナフトールのクロム錯体、クロルフェノールとアニリドを含むアゾナフトールの鉄錯体、ジターシャリーブチルサリチル酸クロム錯体等を添加した場合も、フェノール樹脂製被膜の帯電付与性を多少は向上させ得るが、本発明で用いる第４級アンモニウム塩化合物ほどの顕著な効果はない。更に、上記に挙げた負帯電制御剤は、材料によってはフェノール樹脂中に分散されにくく、その結果、上記と同様に被覆層の強度低下を招き易いものがある。
【００１６】
これに対し、フェノール樹脂に、本発明で用いる特定の第４級アンモニウム塩化合物を添加した樹脂組成物を使用して被覆層を形成すると、先に述べたように、結着樹脂であるフェノール樹脂を加熱硬化させて被覆層を形成した場合に、該第４級アンモニウム塩化合物がフェノール樹脂の構造中に取り込まれる。このため、前記したネガ性シリカ粒子或いはネガ性テフロン粒子等のような粒子添加系の場合と異なり、部分的にではなく、被覆層全体として正帯電性現像剤に対する正摩擦帯電付与性が向上する。更に、粒子添加系の被膜と異なり、加工性が損なわれたり、被覆層の強度低下を生じることもない。
従って、上記した結着樹脂を用いて形成された被覆層が設けられている現像剤担持体を有する現像装置を用いることによって、常温常湿下においては勿論のこと、高温高湿下、或いは低湿下においても良好な画像を提供することが可能となる。更に、長期耐久においても安定した画像の提供ができる。
【００１７】
本発明に好適に用いられる、それ自身が鉄粉に対して正帯電性である第４級アンモニウム塩化合物としては、具体的には、以下のようなものが挙げられるが、勿論、本発明は、これらに限定されるものではない。
【化３】

【化４】

【化５】

【００１８】
【化６】

【化７】

【化８】

【化９】

【化１０】

【００１９】
上記に例示したような本発明で使用する第４級アンモニウム塩化合物の添加量は、フェノール樹脂１００部に対して１〜１００部とすることが好ましい。１部未満では添加による帯電付与性の向上が見られず、１００部を超えると結着樹脂中への分散不良となり被膜強度の低下を招き易い。
【００２０】
又、本発明者らが鋭意検討を重ねた結果、本発明において使用する結着樹脂を構成するフェノール樹脂として、その製造工程において、触媒として含窒素化合物を用いて製造されたものを用いると、特に、加熱硬化時に第４級アンモニウム塩化合物がフェノール樹脂の構造中に取り込まれ易く、好ましいことがわかった。従って、本発明においては、このような作用を有する、その製造工程において触媒として含窒素化合物を用いて製造されたフェノール樹脂を現像剤担持体上の被覆層を構成する材料の１つとして用いれば、良好な正帯電付与性を有する現像装置の実現が可能となる。
【００２１】
本発明で好適に使用し得る、フェノール樹脂の製造工程において触媒として用いられる含窒素化合物としては、例えば、酸性触媒としては、硫酸アンモニウム、燐酸アンモニウム、スルファミド酸アンモニウム、炭酸アンモニウム、酢酸アンモニウム、マレイン酸アンモニウムといったアンモニウム塩又はアミン塩類が挙げられ、塩基性触媒としては、アンモニア、或は、ジメチルアミン、ジエチルアミン、ジイソプロピルアミン、ジイソブチルアミン、ジアミルアミン、トリメチルアミン、トリエチルアミン、トリｎ−ブチルアミン、トリアミルアミン、ジメチルベンジルアミン、ジエチルベンジルアミン、ジメチルアニリン、ジエチルアニリン、Ｎ，Ｎ−ジｎ−ブチルアニリン、Ｎ，Ｎ−ジアミルアニリン、Ｎ，Ｎ−ジｔ−アミルアニリン、Ｎ−メチルエタノールアミン、Ｎ−エチルエタノールアミン、ジエタノールアミン、トリエタノールアミン、ジメチルエタノールアミン、ジエチルエタノールアミン、エチルジエタノールアミン、ｎ−ブチルジエタノールアミン、ジｎ−ブチルエタノールアミン、トリイソプロパノールアミン、エチレンジアミン、ヘキサメチレンテトラミン等のアミノ化合物、ピリジン、α−ピコリン、β−ピコリン、γ−ピコリン、２，４−ルチジン、２，６−ルチジン等のピリジン及びその誘導体、キノリン化合物、イミダゾール、２−メチルイミダゾール、２，４−ジメチルイミダゾール、２−エチル−４−メチルイミダゾール、２−フェニルイミダゾール、２−フェニル−４−メチルイミダゾール、２−ヘプタデシルイミダゾール等のイミダゾール及びその誘導体等の含窒素複素環式化合物等が挙げられる。
【００２２】
本発明において、上記した形成材料によって現像剤担持体上に形成される被覆層は、チャージアップによる現像剤の現像剤担持体上への固着や、現像剤のチャージアップに伴って生じる現像剤担持体の表面から現像剤への帯電付与不良を防ぐためには、導電性であることが望ましい。又、被覆層の体積抵抗値としては、好ましくは１０⁴Ω・ｃｍ以下、より好ましくは１０³Ω・ｃｍ以下である。即ち、被覆層の体積抵抗値が、１０⁴Ω・ｃｍを超えると現像剤への帯電付与不良が発生し易く、その結果、ブロッチが発生し易い。
【００２３】
本発明において、被覆層の抵抗値を、上記の値に調整するためには、下記に挙げる導電性物質を被覆層中に含有させることが好ましい。この際に使用される導電性物質としては、例えば、アルミニウム、銅、ニッケル、銀等の金属粉体、酸化アンチモン、酸化インジウム、酸化スズ等の金属酸化物、カーボンファイバー、カーボンブラック、グラファイト等の炭素物等が挙げられる。本発明においては、これらのうち、カーボンブラック、とりわけ導電性のアモルファスカーボンは、特に電気伝導性に優れ、高分子材料に充填して導電性を付与したり、その添加量をコントロールするだけで、ある程度任意の導電度を得ることができるため好適に用いられる。又、本発明において好適なこれらの導電性物質の添加量は、結着樹脂１００部に対して１〜１００部の範囲とすることが好ましい。
【００２４】
更に、本発明においては、現像剤担持体表面への現像剤の付着をより軽減化するため、被覆層中に固体潤滑剤を混合させることもできる。この際に使用し得る固体潤滑剤としては、例えば、二硫化モリブデン、窒化硼素、グラファイト、フッ化グラファイト、銀−セレンニオブ、塩化カルシウム−グラファイト、滑石が挙げられる。又、本発明で使用することのできるこれらの固体潤滑剤の添加量は、結着樹脂１００部に対して１〜１００部の範囲とすることが好ましい。
【００２５】
本発明で好適に使用される上記のような構成を有する現像剤担持体表面の被覆層の表面粗さは、ＪＩＳ中心線平均粗さ（Ｒａ）で０．１〜３．５μｍの範囲にあることが好ましい。即ち、Ｒａが０．１μｍ未満では、現像剤担持体上におけるトナーの帯電量が高くなり過ぎ現像性が不充分となるし、又、現像領域への現像剤の搬送性に劣り、充分な画像濃度が得られにくくなる。一方、Ｒａが３．５μｍを超えると、現像剤担持体上に形成されるトナーコート層にムラが生じ、画像上での濃度ムラの原因となる。
【００２６】
次に、上記したような優れた効果を発揮し得る現像剤担持体が組み込まれて構成される本発明の現像装置の一例を、図を参照しながら説明する。
図２は、本発明の現像装置の一例を示す概略構成図である。図２において、公知のプロセスにより形成された静電潜像を担持する像担持体、例えば、電子写真感光ドラム７は、矢印Ｂ方向に回転される。現像剤担持体としての現像スリーブ１４は、ホッパー９によって供給された一成分磁性現像剤である磁性トナー１０を担持して、矢印Ａ方向に回転することによって、現像スリーブ１４と感光ドラム７とが対向している現像部Ｄ（現像領域）に磁性トナー１０を搬送する。この現像スリーブ１４内には、磁性トナー１０を現像スリーブ１４上に磁気的に吸引・保持するための磁石１１が配置されている。このような現像スリーブ１４上に担持された磁性トナー１０は、現像スリーブ１４との摩擦によって、感光ドラム７上の静電潜像を現像可能にする摩擦帯電電荷を得る。
【００２７】
又、図１に例示した現像装置では、現像部Ｄに搬送されていく磁性トナー１０の層厚を規制するために、強磁性金属からなる現像剤層厚規制部材である規制ブレード８が、ホッパー９から、現像スリーブ１４の表面から約２００〜３００μｍのギャップ幅をもって現像スリーブ１４に臨むように垂下されている。この結果、現像スリーブ１４内の磁石１１の磁極Ｎ１からの磁力線がブレード８に集中することにより、現像スリーブ１４上に磁性トナー１０の薄層が形成される。尚、ブレード８としては、非磁性ブレードを使用することもできる。
【００２８】
本発明においては、上記のようにして現像スリーブ１４上に形成される磁性トナー１０の薄層の厚みは、現像部Ｄにおける現像スリーブ１４と感光ドラム７との間の最小間隙よりも、更に薄いものであることが好ましい。このようなトナー薄層により静電潜像を現像する方式の現像装置、即ち、非接触型現像装置に、本発明は特に効果的である。
しかし、勿論、現像部において、トナー層の厚みが現像スリーブ１４と感光ドラム７との間の最小間隙以上の厚みである現像装置、即ち、接触型現像装置にも、本発明は適用することができる。以下、説明の煩雑さを避けるため、非接触型の現像装置を例にとって、更に説明する。
【００２９】
上記構成を有する本発明に好適な現像スリーブ１４では、その表面に担持された磁性トナー１０を飛翔させるために、電源１５により現像バイアス電圧が印加される。本発明においては、この現像バイアス電圧として直流電圧を使用するときは、静電潜像の画像部（磁性トナー１０が付着して可視化される領域）の電位と背景部の電位との間の値の電圧を現像スリーブ１４に印加されることが好ましい。一方、現像画像の濃度を高め或いは階調性を向上させるためには、現像スリーブ１４に交番バイアス電圧を印加し、現像部Ｄに向きが交互に反転する振動電界を形成してもよい。この場合には、上記画像部の電位と背景部の電位の間の値を有する直流電圧成分が重畳された交番バイアス電圧を、現像スリーブ１４に印加することが好ましい。
【００３０】
又、高電位部と低電位部とを有する静電潜像の高電位部にトナーを付着させて可視化する所謂正規現像では、静電潜像の極性と逆極性に帯電するトナーを使用し、一方、静電潜像の低電位部にトナーを付着させて可視化する所謂反転現像では、トナーは静電潜像の極性と同極性に帯電するトナーを使用することが好ましい。尚、高電位、低電位というのは、絶対値による表現である。いずれにしても磁性トナー１０は、現像スリーブ１４との摩擦により静電潜像を現像するための極性に帯電される。磁性トナー１０に外添したシリカも、現像スリーブ１４との摩擦により帯電する。
【００３１】
【実施例】
以下に、実施例及び比較例を挙げて本発明をより具体的に説明する。表１に、実施例及び比較例で得られた現像剤担持体（現像スリーブ）の構成をまとめて示した。
（実施例１）
下記の材料を混合し、φ２ｍｍのジルコニア粒子を充填剤として、サンドミルにて３時間の分散処理を行った後、ジルコニア粒子を篩いで分離し、ＩＰＡで固形分を３０％に調整して、フェノール樹脂中に鉄粉に対して正帯電性である第４級アンモニウム塩化合物を添加した樹脂組成物を得た。

【化１１】

上記式（１）で表される第４級アンモニウム塩化合物について、鉄粉との摩擦帯電量を市販の摩擦帯電量測定器（東芝ケミカル製ＴＢ−２００型）を用いてブローオフ法により測定したところ、正極性であった。
【００３２】
上記で得られた樹脂組成物は、塗料状をしており、その組成は、Ｃ（カーボン）／ＧＦ（グラファイト）／Ｂ（フェノール樹脂）／Ｐ（第４級アンモニウム塩化合物）＝０．２／０．８／２．５／０．５であった。次に、この樹脂組成物をスプレー法にて、φ２０ｍｍのアルミニウム製の円筒体上に塗布して１０μｍの被膜を形成させ、その後、熱風乾燥機により１５０℃で３０分間加熱・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ１を作製した。上記で使用した樹脂組成物の体積抵抗値を、絶縁シート上に塗料状の樹脂組成物をバーコーターにてコートして乾燥させた後、これを定形にカットし、低抵抗率計ロレスター（三菱油化社製）を用いて測定した。この結果、１．５×１０Ω・ｃｍであった。
【００３３】
上記で得られた現像スリーブ１を、キヤノン社製の複写機ＮＰ６０３５（商品名）に組み込み、２４℃／６５％ＲＨの常温常湿（Ｎ／Ｎ）、２４℃／１０％ＲＨの常温低湿（Ｎ／Ｌ）、及び３０℃／８０％ＲＨの高温高湿（Ｈ／Ｈ）の３環境において画出しを行った。
その際、画出しに用いた現像剤としては、下記の構成材料を溶融混練、粉砕及び分散して得られた、重量平均粒径６μｍの正帯電トナーに正帯電性外添剤として、トリメトキシシリル−γ−プロピルベンジルアミンでカップリング処理したコロイダルシリカを０．９％外添した正帯電性一成分系磁性現像剤を用いた。
・スチレン−アクリル系樹脂（Ｔｇ５６℃） １００質量部
・マグネタイト ８０質量部
・正電荷制御剤 ２質量部
・低分子量ポリプロピレン ４質量部
【００３４】
（評価）
Ａ．画像特性
画出し耐久における、ブロッチ（現像剤担持体上のトナーコート層のコートムラ）の発生、ゴーストの発生及びφ５画像濃度の変化について、常温常湿（Ｎ／Ｎ）、常温低湿（Ｎ／Ｌ）及び高温高湿（Ｈ／Ｈ）の３環境下で、以下の方法及び基準にて評価を行い、反転カブリについては、常温低湿（Ｎ／Ｌ）環境で、以下の方法及び基準にて評価した。
【００３５】
▲１▼ブロッチ
画出し試験によって得られたベタ黒及びハーフトーン画像を目視にて観察し、１枚後、１０００枚後及び１０万枚後の画像について、ブロッチを以下の基準で評価した。その結果、表２に示した様に、良好な結果が得られた。
◎：優秀
○：良好
△：普通
×：悪い
【００３６】
▲２▼ゴースト
画出し試験によって得られたゴーストチャートのハーフトーン画像を目視にて観察し、１枚後、１０００枚後及び１０万枚後の画像についてゴーストを以下の基準で評価した。その結果、表３に示した様に、良好な結果が得られた。
◎：優秀
○：良好
△：普通
×：悪い
【００３７】
▲３▼φ５画像濃度
φ５画像について、１枚、５万枚、１０万枚、１５万枚、２０万枚、２５万枚及び３０万枚画出し後における、画像比率５．５％のテストチャート上のφ５黒丸の画像濃度を、反射濃度計ＲＤ９１８（マクベス社製）で測定して、画像濃度の耐久について調べた。その結果、図３（１）に示した様に、長期耐久についても、安定した画像濃度が得られた。
【００３８】
▲４▼反転カブリ
１枚、１０枚、１００枚及び１０００枚画出しして、反転カブリについて調べた。反転カブリは、複写機本体の濃度補正キーを最も濃度薄になるように設定して画像を形成した１２８ｇ／ｍ²の厚紙のベタ白部の反射率（Ｄ₁）を測定し、更に、画像形成に用いた厚紙と同一カットの未使用の厚紙の反射率（Ｄ₂）を測定し、Ｄ₂−Ｄ_１の値を５点求め、その平均値をカブリ濃度とした。その際の反射率は、ＴＣ−６ＤＳ（東京電色製）で測定した。その結果、図３（２）に示した様に、良好な結果が得られた。
【００３９】
▲５▼トリボ
現像剤担持体上の吸引法トリボ値の測定については、以下の方法で行った。即ち、現像剤担持体表面の形状に沿った金属製の吸引口を取付けた、円筒濾紙を有する測定容器を用いて、画像形成直後（５分以内）の現像剤担持体表面上の現像剤層を過不足なく一様に吸引できるように吸引圧を調整して、現像剤担持体表面上の現像剤を吸引する。このとき吸引された現像剤の電荷Ｑを６１６ディジタルエレクトロメーター（ＫＥＩＴＨＬＥＹ製）で測定し、又、この現像剤の質量Ｍを測定し、Ｑ／Ｍ（ｍＣ／ｋｇ）により現像剤のトリボ値を計算した。測定は１０００枚後に行った。その結果、表１に示した様に、良好な結果が得られた。
【００４０】
▲６▼白筋
画出し試験によって得られたベタ黒及びハーフトーン画像を目視にて観察し、１枚後、１０００枚後及び１０万枚後の画像について白筋を以下の基準で評価した。その結果、表４に示した様に、良好な結果が得られた。
◎：優秀
○：良好
△：普通
×：悪い
【００４１】
（実施例２）
実施例１で用いた式（１）で表される第４級アンモニウム塩化合物の代わりに、下記式（２）で表される第４級アンモニウム塩化合物を用いた以外は、実施例１と同様の処方及び操作で、塗料状の樹脂組成物を得た。尚、下記式（２）で表される第４級アンモニウム塩化合物についても、鉄粉との摩擦帯電量をブローオフ法により測定したところ、実施例１と同様に正極性であった。
【化１２】

【００４２】
得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｐ＝０．２／０．８／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を、実施例１と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ２を作製した。
更に、得られた現像スリーブ２を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図４に示した通り良好な結果が得られた。
【００４３】
（実施例３）
実施例１で用いた式（１）の第４級アンモニウム塩化合物の代わりに、下記式（３）で表される第４級アンモニウム塩化合物を用いた以外は、実施例１と同様の処方及び操作で、塗料状の樹脂組成物を得た。下記式（３）で表される第４級アンモニウム塩化合物についても、鉄粉との摩擦帯電量をブローオフ法により測定したところ、実施例１と同様に正極性であった。
【化１３】

【００４４】
得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｐ＝０．２／０．８／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を、実施例１と同様にして、アルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ３を作製した。
更に、得られた現像スリーブ３を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図５に示した通り良好な結果が得られた。
【００４５】
（実施例４）
実施例１で用いた式（１）の第４級アンモニウム塩化合物の代わりに、下記式（４）で表される第４級アンモニウム塩化合物を用いた以外は、実施例１と同様の処方及び操作で、塗料状の樹脂組成物を得た。下記式（４）で表される第４級アンモニウム塩化合物も、鉄粉との摩擦帯電量をブローオフ法により測定したところ、実施例１と同様に正極性であった。
【化１４】

【００４６】
得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｐ＝０．２／０．８／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を、実施例１と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ４を作製した。
更に、得られた現像スリーブ４を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図６に示した通り良好な結果が得られた。
【００４７】
（実施例５）
下記の材料を混合し、φ２ｍｍのジルコニア粒子を充填剤として、サンドミルにて３時間の分散処理を行った後、ジルコニア粒子を篩いで分離し、ＩＰＡで固形分を３０％に調整して、フェノール樹脂中に、鉄粉に対して正帯電性である第４級アンモニウム塩化合物を添加した樹脂組成物を得た。

【００４８】
上記で得られた樹脂組成物は、塗料状をしており、その組成は、Ｃ（カーボン）／ＢＮ（窒化硼素）／Ｂ（フェノール樹脂）／Ｐ（第４級アンモニウム塩化合物）＝０．２／１．６／２．５／０．５であった。本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
次に、この樹脂組成物をスプレー法にて、φ２０ｍｍのアルミニウム製の円筒体上に塗布し、１０μｍの被膜を形成させ、その後、熱風乾燥機により１５０℃で３０分間加熱・硬化させて表面に導電性樹脂被覆層を有する現像スリーブ５を作製した。
更に、得られた現像スリーブ５を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図７に示した通り良好な結果が得られた。
【００４９】
（実施例６）
実施例５で用いた式（１）の第４級アンモニウム塩化合物の代わりに、実施例２で用いた式（２）で表される鉄粉との帯電極性が正極性である第４級アンモニウム塩化合物を用い、更に、ヘキサメチレンテトラミンを触媒として製造されたフェノール樹脂の代わりに、トリメチルアミンを触媒として用いたフェノール樹脂を使用する以外は実施例５と同様の処方及び操作で、塗料状の樹脂組成物を得た。
得られた樹脂組成物の組成は、Ｃ／ＢＮ／Ｂ／Ｐ＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を用いて、実施例５と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ６を作製した。
更に、得られた現像スリーブ６を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図８に示した通り良好な結果が得られた。
【００５０】
（実施例７）
実施例５で用いた式（１）の第４級アンモニウム塩化合物の代わりに、実施例３で用いた式（３）の第４級アンモニウム塩化合物を用い、更に、ヘキサメチレンテトラミンを触媒として製造されたフェノール樹脂の代わりに、トリエチルアミンを触媒として用いたフェノール樹脂を使用する以外は実施例５と同様の処方及び操作で、塗料状の樹脂組成物を得た。
得られた樹脂組成物の組成は、Ｃ／ＢＮ／Ｂ／Ｐ＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を用いて、実施例５と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ７を作製した。
更に、得られた現像スリーブ７を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図９に示した通り良好な結果が得られた。
【００５１】
（実施例８）
実施例５で用いた式（１）の第４級アンモニウム塩化合物の代わりに、実施例４で用いた式（４）の第４級アンモニウム塩化合物を用い、更に、ヘキサメチレンテトラミンを触媒として製造されたフェノール樹脂の代わりに、ピリジンを触媒として用いたフェノール樹脂を使用する以外は実施例５と同様の処方及び操作で、塗料状の樹脂組成物を得た。
得られた樹脂組成物の組成は、Ｃ／ＢＮ／Ｂ／Ｐ＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を用いて、実施例５と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ８を作製した。
更に、得られた現像スリーブ８を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１０に示した通り、良好な結果が得られた。
【００５２】
（実施例９）
下記の材料を混合し、φ２ｍｍのジルコニア粒子を充填剤として、サンドミルにて３時間の分散処理を行った後、ジルコニア粒子を篩いで分離し、ＩＰＡで固形分を３５％に調整して、フェノール樹脂と鉄粉に対して正帯電性である第４級アンモニウム塩化合物とを少なくとも有する樹脂組成物を得た。

上記で得られた樹脂組成物は、塗料状をしており、その組成は、Ｃ（カーボン）／ＭｏＳ₂（二硫化モリブデン）／Ｂ（フェノール樹脂）／Ｐ（第４級アンモニウム塩化合物）＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
【００５３】
次に、この樹脂組成物をスプレー法にて、φ２０ｍｍのアルミニウム製の円筒体上に塗布し、１０μｍの被膜を形成させ、その後、熱風乾燥機により１５０℃で３０分間加熱・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ９を作製した。
更に、得られた現像スリーブ９を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１１に示した通り、良好な結果が得られた。
【００５４】
（実施例１０）
実施例９で用いた式（１）の第４級アンモニウム塩化合物の代わりに、実施例２で用いた式（２）で表される、鉄粉との帯電極性が正極性である第４級アンモニウム塩化合物を用い、更に、ヘキサメチレンテトラミンを触媒として製造されたフェノール樹脂の代わりに、トリメチルアミンを触媒として用いたフェノール樹脂を使用する以外は実施例９と同様の処方及び操作で、塗料状の樹脂組成物を得た。
得られた樹脂組成物の組成は、Ｃ／ＭｏＳ₂／Ｂ／Ｐ＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を用いて、実施例９と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ１０を作製した。
更に、得られた現像スリーブ１０を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１２に示した通り、良好な結果が得られた。
【００５５】
（実施例１１）
実施例９で用いた式（１）の第４級アンモニウム塩化合物の代わりに、実施例３で用いた式（３）で表される、鉄粉との帯電極性が正極性である第４級アンモニウム塩化合物を用い、更に、ヘキサメチレンテトラミンを触媒として製造されたフェノール樹脂の代わりに、トリエチルアミンを触媒として用いたフェノール樹脂を使用する以外は、実施例９と同様の処方及び操作で、塗料状の樹脂組成物を得た。
得られた樹脂組成物の組成は、Ｃ／ＭｏＳ₂／Ｂ／Ｐ＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を用いて、実施例９と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ１１を作製した。
更に、得られた現像スリーブ１１を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１３に示した通り良好な結果が得られた。
【００５６】
（実施例１２）
実施例９で用いた式（１）の第４級アンモニウム塩化合物の代わりに、実施例４で用いた式（４）で表される、鉄粉との摩擦帯電極性が正極性である第４級アンモニウム塩化合物を用い、更に、ヘキサメチレンテトラミンを触媒として製造されたフェノール樹脂の代わりに、ピリジンを触媒として用いたフェノール樹脂を使用する以外は、実施例９と同様の処方及び操作で、塗料状の樹脂組成物を得た。
得られた樹脂組成物の組成は、Ｃ／ＭｏＳ₂／Ｂ／Ｐ＝０．２／１．６／２．５／０．５であった。又、本実施例で使用した塗料状の樹脂組成物についても、実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。この樹脂組成物を用いて、実施例９と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する現像スリーブ１２を作製した。
更に、得られた現像スリーブ１２を用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１４に示した通り良好な結果が得られた。
【００５７】
（比較例１）
実施例で使用したと同様のφ２０ｍｍのアルミニウム製円筒体の表面に、ＦＧＢ＃３００でサンドブラストしただけのものを比較例１の現像スリーブとした。これを用いて、実施例１と同様の方法で画出し評価を行った。その結果、表２及び表３に示したように、ブロッチがひどく、これ以外の画像評価をすることは不可能であった。
【００５８】
（比較例２）
下記の処方とした以外は実施例１と同様にして塗料状の樹脂組成物を得た。得られた樹脂組成物は、塗料状をしており、その組成は、Ｃ／ＧＦ／Ｂ／Ｐ＝０．２／０．８／２．５／０であった。

この樹脂組成物を用いて、実施例１と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する比較例２の現像スリーブを作製した。この現像スリーブを用いて実施例１と同様にして画出し評価した。その結果、表２、表３、表４及び図１５に示したように、カブリについては初期のみ若干悪いだけであったが、耐久での画像濃度の低下がみられた。又、本比較例で使用した塗料状の樹脂組成物についても実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
【００５９】
（比較例３）
実施例１で用いた式（１）の第４級アンモニウム塩化合物の代わりに、クロルフェノールを含むアゾナフトールのクロム錯体（Ｓ）を用いた以外は実施例１と同様の処方及び操作で樹脂組成物を作製した。得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｓ＝０．２／０．８／２．５／０．５であった。ここで、クロルフェノールを含むアゾナフトールのクロム錯体（Ｓ）の、鉄粉との摩擦帯電量を、実施例１と同様にブローオフ法により測定したところ、負極性であった。又、本比較例で使用した塗料状の樹脂組成物についても実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
この樹脂組成物を用いて、実施例１と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する比較例３の現像スリーブを作製した。
更に、得られた現像スリーブを用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１６に示した通り、カブリについては５０枚位までのカブリが悪く、又、耐久で画像濃度の低下がみられた。
【００６０】
（比較例４）
実施例１で用いた式（１）の第４級アンモニウム塩化合物の代わりにニグロシン（Ｎ）を用いた以外は実施例１と同様の処方及び操作で樹脂組成物を作製した。得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｎ＝０．２／０．８／２．５／０．５）であった。ここで、ニグロシンの鉄粉との摩擦帯電量を、実施例１と同様にブローオフ法により測定したところ正極性であった。又、本比較例で使用した塗料状の樹脂組成物についても実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
この樹脂組成物を用いて、実施例１と同様のアルミニウム基体上に塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する比較例３の現像スリーブを作製した。
更に、得られた現像スリーブを用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１７に示したように、カブリについては１０００枚位までのカブリが悪く、又、耐久の早い段階で画像濃度の低下がみられた。
【００６１】
（比較例５）
実施例１で用いた式（１）の第４級アンモニウム塩化合物の代わりに、下記式（９）の第４級アンモニウム塩化合物を用いた以外は実施例１と同様の処方及び操作で樹脂組成物を得た。得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｐ＝０．２／０．８／２．５／０．５であった。下記式（９）の第４級アンモニウム塩化合物についても、鉄粉との摩擦帯電量を実施例１と同様にブローオフ法により測定したが、実施例１とは異なり負極性であった。又、本比較例で使用した塗料状の樹脂組成物についても実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
【化１５】

この樹脂組成物を用い、実施例１と同様のアルミニウム基体上に、塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する比較例５の現像スリーブを作製した。
更に、得られた現像スリーブを用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１８に示した通り、カブリについては１０枚以降は良好であったが、画像濃度の低下がみられた。
【００６２】
（比較例６）
実施例１において、アンモニアを触媒として製造されたフェノールの代わりに、ＰＭＭＡ樹脂を用いた以外は実施例１と同様の処方及び操作で樹脂組成物を得た。得られた樹脂組成物の組成は、Ｃ／ＧＦ／Ｂ／Ｐ＝０．２／０．８／２．５／０．５であった。又、本比較例で使用した塗料状の樹脂組成物についても実施例１と同様にして体積抵抗値を求めたところ、その値は表１に示したようであった。
この樹脂組成物を用い、実施例１と同様のアルミニウム基体上に、塗布・乾燥・硬化させて、表面に導電性の樹脂被覆層を有する比較例６の現像スリーブを作製した。
更に、得られた現像スリーブを用いて実施例１と同様にして、画出し評価を行った。その結果、表２、表３、表４及び図１９に示した通り、カブリについては１０００枚まで悪く、画像濃度は初期から悪かった。
【００６３】
表１：現像剤担持剤の構成

注） ＊１：鉄粉に対する摩擦帯電極性
【００６４】
表２：評価結果（ブロッチ）

【００６５】
表３：評価結果（ゴースト）

【００６６】
表４：評価結果（白筋）

【００６７】
【発明の効果】
以上説明したように、本発明によれば、現像剤担持体の外周に設ける被覆層の形成材料として、導電性物質と、フェノール樹脂と、鉄粉に対して自身が正帯電性である第４級アンモニウム塩化合物を少なくとも含有する樹脂組成物を用いることによって、上記樹脂組成物を加熱硬化してフェノール樹脂被膜を形成した場合に、従来行われている帯電付与粒子を添加した場合と異なり、第４級アンモニウム塩化合物がフェノール樹脂中に分散するのではなくその構造中に取り込まれるため、被覆層の耐磨耗性が格段に向上し、長期耐久に耐え得るものとなる。
【００６８】
更に、本発明によれば、現像剤担持体の外周に設けられる被覆層が、第４級アンモニウム塩化合物がフェノール樹脂の構造中に取り込まれて形成されるため、フェノール樹脂自身の正帯電性トナーを有する現像剤に対する正摩擦帯電付与性が向上する。
従って、上記の樹脂組成物を、正帯電性トナーを有する現像剤を用いる現像剤担持体の表面上に形成する導電性被覆層の結着樹脂材料として用いることで、現像剤への帯電付与性が安定となり、且つ該被覆層の耐磨耗性が向上する。この結果、常温常湿下においては勿論のこと、高温高湿や低湿度下においても、画像濃度の低下、ゴースト、ブロッチ、及びベタカブリといった画質不良の発生しない高品位の画像を長期に亘って得ることができ、安定した高品位の画像の提供が可能となる。
【００６９】
更に、本発明においては、現像剤担持体の外周に設ける被覆層を形成する結着樹脂にフェノール樹脂を用いているので、正帯電性トナーを有する現像剤に対する正摩擦帯電付与性のあるテフロン等のような各種溶媒に溶け難い樹脂に比べ、現像剤担持体への塗工が容易である。
【図面の簡単な説明】
【図１】本発明における現像剤担持体の一例を示す概略部分断面図である。
【図２】 本発明の現像装置の一例を示す概略図である。
【図３】実施例１の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図４】実施例２の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図５】実施例３の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図６】実施例４の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図７】実施例５の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図８】実施例６の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図９】実施例７の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１０】実施例８の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１１】実施例９の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１２】実施例１０の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１３】実施例１１の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１４】実施例１２の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１５】比較例２の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１６】比較例３の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１７】比較例４の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１８】比較例５の耐久画像濃度推移及びカブリ推移を示すグラフ。
【図１９】比較例６の耐久画像濃度推移及びカブリ推移を示すグラフ。
【符号の説明】
１：被覆層
２：導電性物質
３：結着樹脂
４：固体潤滑剤
５：円筒状基体
７：感光ドラム
８：規制ブレード
９：ホッパー
１０：トナー
１１：磁石
１２：円筒状基体
１３：被覆層
１４：現像スリーブ
１５：電源
１６：攪拌器
１７：弾性板
Ａ：現像スリーブの回転方向
Ｂ：感光ドラムの回転方向
Ｄ：現像部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device and a developing method for developing a latent image formed on an image carrier such as an electrophotographic photosensitive member or an electrostatic recording derivative to visualize the latent image.
[0002]
[Prior art]
Conventionally, for example, as a developing device that visualizes an electrostatic latent image formed on the surface of a photosensitive drum as an image carrier with toner as a one-component developer, friction between toner particles, developer carrier The toner particles are positively or negatively charged by the friction between the developing sleeve and the toner particles and the friction between the toner sleeve and the member (developer layer thickness regulating member) that regulates the toner application amount on the developing sleeve. Then, the charged toner is applied very thinly on the developing sleeve, conveyed to a developing area where the photosensitive drum and the developing sleeve face each other, and the toner flies to the electrostatic latent image on the surface of the photosensitive drum in the developing area. And an electrostatic latent image on the photosensitive drum is made visible as a toner image.
[0003]
The developer carrier used in the conventional development system as described above is formed by, for example, molding a metal, an alloy, or a metal compound into a cylindrical shape, and the surface thereof has a predetermined surface roughness by electrolysis, blast, file, or the like. What was processed in this way is used.
However, when such a developer carrying member is used, in the developer layer formed on the surface of the developer carrying member by the developer layer thickness regulating member, the developer layer existing in the vicinity of the surface of the developer carrying member. The developer inside has a very high charge, and is attracted to the surface of the developer carrier strongly by the mirroring force, so that there is no opportunity for friction between the toner and the developer carrier, and the toner is suitable. It becomes impossible to have a good charge. For this reason, when an image is formed under such circumstances, sufficient development and transfer are not performed, and the image has many image density unevenness and character scattering.
[0004]
In recent years, in order to realize low-temperature fixing of a developer and high-definition image formation required for energy saving, it is desired to reduce the particle size of toner. When a conventional developer carrier as described above is used in a model using such a toner having a small particle diameter, as described below, sufficiently low temperature fixing of the developer and high-definition image It was difficult to realize the formation. For example, for low-temperature fixing of the developer, the glass transition temperature Tg of the developer tends to be set lower, or a low-melting substance such as wax is added to the developer in a larger amount. These developers are affected by the temperature rise of the main body of an electrophotographic apparatus or the like, and are easily fused on the developer carrying member, which may cause a decrease in image density, white streaks, blotches, or the like.
[0005]
Japanese Patent Application Laid-Open No. 1-112253, Japanese Patent Application Laid-Open No. 2-284158, and the like propose to use a toner having a small particle diameter in order to improve image quality and high definition. In such a toner having a small particle diameter, the surface area per unit weight is large, so that the surface charge tends to be large, and the toner is fixed to the developer carrying member by a so-called charge-up phenomenon. The developer supplied on the carrier becomes difficult to be charged, and the charge amount of the developer tends to be non-uniform. For this reason, a sleeve ghost is likely to occur on the image, and the obtained image tends to be a non-uniform image such as a streak-like image or a haze-like image such as a solid image or a halftone image.
[0006]
On the other hand, in JP-A-1-277256, JP-A-3-36570, etc., the generation of the developer having such an excessive charge and the strong adhesion of the developer to the developer carrier are prevented. Therefore, a method has been proposed in which a film made of a resin composition in which a conductive material such as carbon or graphite or a solid lubricant is dispersed in a resin is formed on a developer carrier.
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to prevent the toner from being overcharged in the developing device, to keep the toner charge amount high, and to prevent toner fusion on the developer carrier. It is an object of the present invention to provide a developing device and a developing method capable of effectively preventing a decrease in image density, white streaks and blotches caused by the above.
Another object of the present invention is to provide a developing apparatus and a developing method capable of obtaining a good image not only in an environment of normal temperature and humidity but also in an environment of high temperature and high humidity or low humidity.
It is another object of the present invention to provide a developing device and a developing method that can provide a stable image even in a long-term durability under any environment by providing a developing sleeve having excellent wear resistance.
Furthermore, another object of the present invention is to provide a developing device and a developing method capable of eliminating a sleeve ghost.
[0008]
[Means for Solving the Problems]
The above object is achieved by the present invention described below. That is, according to the present invention, a developer having a positively chargeable toner accommodated in a developer container is carried on a developer carrier, and a thin layer of developer is formed on the developer carrier by a developer layer thickness regulating member. The developer is transported to a developing area where the developer carrying member and the latent image carrying member are opposed to each other, and the latent image on the latent image carrying member is developed with the developer to make a visible image. In the device
A resin coating layer formed of a resin composition containing at least a conductive substance, a phenol resin, and a quaternary ammonium salt compound that is positively charged with respect to iron powder on the surface of the developer carrying member. A developing device, a developer carrier, and a developing method are provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments.
First, the developer carrier characterizing the present invention will be described. The developer carrier used in the present invention has a cylindrical substrate made of metal similar to the conventional one. In the present invention, a conductive substance, a phenol resin, and iron powder are formed on the surface of the substrate. On the other hand, a resin coating layer formed of a resin composition containing at least a quaternary ammonium salt compound that is positively charged is provided.
Hereinafter, an example of a resin coating layer (hereinafter also simply referred to as a coating layer) on the surface of the developer carrying member used in the present invention will be described with reference to FIG. As shown in FIG. 1, a coating layer 1 formed on a cylindrical substrate 5 made of metal or the like is formed on the outer periphery of the cylindrical substrate 5 by a phenol resin which is a binder resin 3. 1 contains a conductive substance, and in some cases, a solid lubricant 4 may be contained together with the conductive substance as illustrated in FIG.
[0010]
As a result of intensive studies on the configuration of the coating layer 1, the present inventors have used a quaternary ammonium salt compound that itself has a positive chargeability with respect to iron powder as a binder resin that is a film forming material. If the contained phenol resin is used, the charge imparting property of the binder resin itself can be improved, so that the charge amount of the toner can be kept high, and by using a conductive substance and a solid lubricant, an excessive amount can be obtained. Generation of a charged developer and strong adhesion of the developer to the developer carrying member can be effectively prevented, and the coating layer itself can be compared with the case where conventional charge imparting particles are added. Therefore, the present inventors have found that it is possible to withstand long-term durability and stably provide a good image for a long period of time.
[0011]
In the present invention, when the binder resin for forming the coating layer on the developer carrying member is configured as described above, the coating layer is a good charge imparting substance for the developer having a positively chargeable toner. The clear reason for becoming is not clear, but the quaternary ammonium salt compound used in the present invention, which is itself positively charged with respect to iron powder, is uniformly dispersed in the phenolic resin when added. Furthermore, when the film is formed by heating and curing, it is taken into the structure of the phenol resin, and as a result, the phenol resin composition itself having the above compound changes to a negatively charged substance. Therefore, if a developer carrier having a coating layer formed using such a material is used, the developer can be suitably charged positively.
[0012]
As the quaternary ammonium salt compound having the above-mentioned function suitably used in the present invention, any compound may be used as long as it has a positive chargeability with respect to iron powder. And the compounds represented.
[Chemical 1]

(R in the formula ₁ , R ₂ , R _Three , R _Four Represents an alkyl group which may have a substituent, an aryl group which may have a substituent, and an aralkyl group, respectively. ₁ ~ R _Four May be the same or different. X ^- Represents the anion of the acid. )
In the above general formula, X ^- Specific examples of the acid ion include organic sulfate ion, organic sulfonate ion, organic phosphate ion, molybdate ion, tungstate ion, heteropolyacid containing molybdenum atom or tungsten atom.
[0013]
On the other hand, for example, a fluorine-containing quaternary ammonium salt compound having a negative chargeability with respect to iron powder as represented by the following formula was also examined. It has been found that the intended purpose of the invention is not achieved. That is, since the compound represented by the following formula has a fluorine atom having a strong electron-withdrawing property in its structure, it itself has a negative chargeability with respect to iron powder. Even if a resin composition in which a resin is dispersed in a phenol resin is used as a binder resin and this is heat-cured to form a coating layer on the developer-carrying member, it is positively charged with respect to iron powder. High positive triboelectric chargeability to a positively chargeable developer could not be obtained as in the case of the present invention using a phenol resin containing a quaternary ammonium salt compound as a binder resin.
[0014]
[Chemical formula 2]

[0015]
In addition, as an additive for improving the positive charge imparting property of the phenol resin, which is a film forming material used for forming the coating layer, to the positively chargeable developer, the additive used in the present invention itself is positively charged with respect to the iron powder. In addition to the quaternary ammonium salt compound, for example, particles such as negative silica or negative Teflon may be considered. In this case, a large amount of these particles may be used to obtain a desired positive charge imparting property. Therefore, the strength of the coating layer is likely to decrease. Addition of azonaphthol chromium complex containing chlorophenol as negative charge control agent, iron complex of azonaphthol containing chlorophenol and anilide, chromium ditertiary butylsalicylate complex, etc. Although the properties can be improved to some extent, they are not as effective as the quaternary ammonium salt compounds used in the present invention. Furthermore, the negative charge control agents listed above are difficult to disperse in the phenolic resin depending on the material, and as a result, there are those that tend to cause a decrease in the strength of the coating layer as described above.
[0016]
In contrast, when a coating layer is formed using a resin composition obtained by adding a specific quaternary ammonium salt compound used in the present invention to a phenol resin, as described above, the phenol resin that is a binder resin. When the coating layer is formed by heat curing, the quaternary ammonium salt compound is incorporated into the structure of the phenol resin. For this reason, unlike the case of the particle addition system such as the negative silica particles or the negative Teflon particles described above, the positive triboelectric charge imparting property to the positively chargeable developer as a whole is improved, not partially. . Further, unlike the particle-added coating, the processability is not impaired and the strength of the coating layer is not reduced.
Therefore, by using a developing device having a developer carrying member provided with a coating layer formed using the above-described binder resin, not only at normal temperature and normal humidity, but also at high temperature and high humidity, or low humidity. It is possible to provide a good image even underneath. Furthermore, a stable image can be provided even in long-term durability.
[0017]
Specific examples of the quaternary ammonium salt compound that is preferably used in the present invention and is positively charged with respect to iron powder include the following. However, it is not limited to these.
[Chemical 3]

[Formula 4]

[Chemical formula 5]

[0018]
[Chemical 6]

[Chemical 7]

[Chemical 8]

[Chemical 9]

[Chemical Formula 10]

[0019]
The amount of the quaternary ammonium salt compound used in the present invention as exemplified above is preferably 1 to 100 parts with respect to 100 parts of the phenol resin. If the amount is less than 1 part, the charge imparting property is not improved by addition, and if it exceeds 100 parts, the dispersion in the binder resin becomes poor and the film strength tends to be lowered.
[0020]
In addition, as a result of repeated extensive studies by the present inventors, as a phenol resin constituting the binder resin used in the present invention, in the production process, a product produced using a nitrogen-containing compound as a catalyst, In particular, it was found that the quaternary ammonium salt compound is preferably incorporated into the structure of the phenol resin at the time of heat curing, which is preferable. Therefore, in the present invention, if a phenol resin having such an action and produced using a nitrogen-containing compound as a catalyst in the production process is used as one of the materials constituting the coating layer on the developer carrier. Thus, it is possible to realize a developing device having a good positive charge imparting property.
[0021]
Examples of the nitrogen-containing compound used as a catalyst in a phenol resin production process that can be suitably used in the present invention include, for example, ammonium sulfate, ammonium phosphate, ammonium sulfamate, ammonium carbonate, ammonium acetate, and ammonium maleate. Examples of the basic catalyst include ammonia, dimethylamine, diethylamine, diisopropylamine, diisobutylamine, diamylamine, trimethylamine, triethylamine, tri-n-butylamine, triamylamine, dimethylbenzylamine. , Diethylbenzylamine, dimethylaniline, diethylaniline, N, N-di-n-butylaniline, N, N-diamilaniline, N, N-di-t-amylaniline N-methylethanolamine, N-ethylethanolamine, diethanolamine, triethanolamine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, n-butyldiethanolamine, di-n-butylethanolamine, triisopropanolamine, ethylenediamine, hexamethylene Amino compounds such as tetramine, pyridine, α-picoline, β-picoline, γ-picoline, pyridine such as 2,4-lutidine, 2,6-lutidine and derivatives thereof, quinoline compounds, imidazole, 2-methylimidazole, 2, Imidazo such as 4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole And nitrogen-containing heterocyclic compounds such as derivatives.
[0022]
In the present invention, the coating layer formed on the developer carrier by the above-described forming material is fixed on the developer carrier due to charge-up, or the developer carrying that occurs when the developer is charged up. In order to prevent poor charging from the surface of the body to the developer, it is desirable to be conductive. The volume resistance value of the coating layer is preferably 10 ^Four Ω · cm or less, more preferably 10 ^Three Ω · cm or less. That is, the volume resistance value of the coating layer is 10 ^Four If it exceeds Ω · cm, poor charging of the developer is likely to occur, and as a result, blotch is likely to occur.
[0023]
In this invention, in order to adjust the resistance value of a coating layer to said value, it is preferable to contain the electroconductive substance mentioned below in a coating layer. Examples of the conductive material used at this time include metal powders such as aluminum, copper, nickel, and silver, metal oxides such as antimony oxide, indium oxide, and tin oxide, carbon fiber, carbon black, and graphite. Examples include carbon materials. In the present invention, among these, carbon black, in particular conductive amorphous carbon, is particularly excellent in electrical conductivity, and it is filled with a polymer material to impart conductivity, or just by controlling the amount of addition, Since arbitrary conductivity can be obtained to some extent, it is preferably used. Moreover, it is preferable that the addition amount of these electroconductive substances suitable in the present invention is in the range of 1 to 100 parts with respect to 100 parts of the binder resin.
[0024]
Furthermore, in the present invention, a solid lubricant can be mixed in the coating layer in order to further reduce the adhesion of the developer to the surface of the developer carrying member. Examples of the solid lubricant that can be used in this case include molybdenum disulfide, boron nitride, graphite, graphite fluoride, silver-selenium niobium, calcium chloride-graphite, and talc. The amount of these solid lubricants that can be used in the present invention is preferably in the range of 1 to 100 parts with respect to 100 parts of the binder resin.
[0025]
The surface roughness of the coating layer on the surface of the developer carrying member preferably used in the present invention is in the range of 0.1 to 3.5 μm in terms of JIS centerline average roughness (Ra). It is preferable. That is, if Ra is less than 0.1 μm, the charge amount of the toner on the developer carrying member becomes too high, and the developability becomes insufficient, and the transportability of the developer to the development area is inferior, so that a sufficient image is obtained. It becomes difficult to obtain the concentration. On the other hand, when Ra exceeds 3.5 μm, unevenness occurs in the toner coat layer formed on the developer carrying member, causing density unevenness on the image.
[0026]
Next, an example of the developing device of the present invention constituted by incorporating a developer carrier capable of exhibiting the above-described excellent effects will be described with reference to the drawings.
FIG. 2 is a schematic configuration diagram showing an example of the developing device of the present invention. In FIG. 2, an image carrier that carries an electrostatic latent image formed by a known process, for example, an electrophotographic photosensitive drum 7 is rotated in the direction of arrow B. The developing sleeve 14 as a developer carrying member carries the magnetic toner 10 which is a one-component magnetic developer supplied by the hopper 9 and rotates in the direction of arrow A, whereby the developing sleeve 14 and the photosensitive drum 7 are connected. The magnetic toner 10 is conveyed to the developing section D (development area) facing each other. A magnet 11 for magnetically attracting and holding the magnetic toner 10 on the developing sleeve 14 is disposed in the developing sleeve 14. The magnetic toner 10 carried on the developing sleeve 14 obtains a triboelectric charge that enables the electrostatic latent image on the photosensitive drum 7 to be developed by friction with the developing sleeve 14.
[0027]
Further, in the developing device illustrated in FIG. 1, in order to regulate the layer thickness of the magnetic toner 10 conveyed to the developing unit D, a regulating blade 8 that is a developer layer thickness regulating member made of a ferromagnetic metal is provided with a hopper. 9 from the surface of the developing sleeve 14 so as to face the developing sleeve 14 with a gap width of about 200 to 300 μm. As a result, the magnetic lines of force from the magnetic pole N 1 of the magnet 11 in the developing sleeve 14 concentrate on the blade 8, whereby a thin layer of the magnetic toner 10 is formed on the developing sleeve 14. As the blade 8, a nonmagnetic blade can be used.
[0028]
In the present invention, the thickness of the thin layer of the magnetic toner 10 formed on the developing sleeve 14 as described above is thinner than the minimum gap between the developing sleeve 14 and the photosensitive drum 7 in the developing portion D. It is preferable. The present invention is particularly effective for a developing device that develops an electrostatic latent image with such a thin toner layer, that is, a non-contact developing device.
However, of course, the present invention can also be applied to a developing device in which the thickness of the toner layer is equal to or greater than the minimum gap between the developing sleeve 14 and the photosensitive drum 7 in the developing unit, that is, a contact type developing device. it can. Hereinafter, in order to avoid complicated explanation, a non-contact type developing device will be further described as an example.
[0029]
In the developing sleeve 14 having the above-described configuration suitable for the present invention, a developing bias voltage is applied by the power source 15 in order to fly the magnetic toner 10 carried on the surface thereof. In the present invention, when a DC voltage is used as the developing bias voltage, a value between the potential of the image portion of the electrostatic latent image (the region visualized by the adhesion of the magnetic toner 10) and the potential of the background portion. Is preferably applied to the developing sleeve 14. On the other hand, in order to increase the density of the developed image or improve the gradation, an alternating bias voltage may be applied to the developing sleeve 14 to form an oscillating electric field whose direction is alternately reversed in the developing portion D. In this case, it is preferable to apply to the developing sleeve 14 an alternating bias voltage in which a DC voltage component having a value between the image portion potential and the background portion potential is superimposed.
[0030]
Further, in so-called regular development in which toner is attached to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion for visualization, toner that is charged with a polarity opposite to that of the electrostatic latent image is used. On the other hand, in the so-called reversal development in which the toner is made visible by attaching the toner to the low potential portion of the electrostatic latent image, it is preferable to use the toner charged with the same polarity as the polarity of the electrostatic latent image. The high potential and the low potential are expressed by absolute values. In any case, the magnetic toner 10 is charged to a polarity for developing the electrostatic latent image by friction with the developing sleeve 14. Silica externally added to the magnetic toner 10 is also charged by friction with the developing sleeve 14.
[0031]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Table 1 summarizes the configurations of the developer carriers (developing sleeves) obtained in the examples and comparative examples.
(Example 1)
After mixing the following materials, using a zirconia particle of φ2 mm as a filler and dispersing for 3 hours in a sand mill, the zirconia particles are separated by sieving, and the solid content is adjusted to 30% with IPA. A resin composition in which a quaternary ammonium salt compound that is positively charged with respect to iron powder was added to the resin was obtained.

Embedded image

About the quaternary ammonium salt compound represented by the above formula (1), the triboelectric charge amount with iron powder was measured by a blow-off method using a commercially available triboelectric charge measuring device (TB-200 type manufactured by Toshiba Chemical). It was positive polarity.
[0032]
The resin composition obtained above is in the form of a paint, and the composition is C (carbon) / GF (graphite) / B (phenol resin) / P (quaternary ammonium salt compound) = 0.2. /0.8/2.5/0.5. Next, this resin composition is applied by spraying onto a φ20 mm aluminum cylinder to form a 10 μm film, and then heated and cured at 150 ° C. for 30 minutes with a hot air dryer. A developing sleeve 1 having a conductive resin coating layer was prepared. The volume resistivity of the resin composition used above was coated with a paint resin composition on an insulating sheet with a bar coater and dried, then cut into a regular shape, and a low resistivity meter Lorester (Mitsubishi) (Manufactured by Yuka Co., Ltd.). As a result, it was 1.5 × 10Ω · cm.
[0033]
The developing sleeve 1 obtained as described above is incorporated into a copying machine NP6035 (trade name) manufactured by Canon Inc., and is at room temperature and humidity (N / N) of 24 ° C./65% RH and room temperature and low humidity of 24 ° C./10% RH N / L) and 3 environments of 30 ° C./80% RH high temperature and high humidity (H / H).
At this time, as a developer used for image output, a positively charged toner having a weight average particle diameter of 6 μm obtained by melt-kneading, pulverizing, and dispersing the following constituent materials is used as a positively chargeable external additive. A positively chargeable one-component magnetic developer to which 0.9% of colloidal silica coupled with methoxysilyl-γ-propylbenzylamine was externally added was used.
・ 100 parts by mass of styrene-acrylic resin (Tg 56 ° C.)
・ 80 parts by mass of magnetite
・ 2 parts by mass of positive charge control agent
・ Low molecular weight polypropylene 4 parts by mass
[0034]
(Evaluation)
A. Image characteristics
In image endurance, the occurrence of blotches (coating unevenness of the toner coat layer on the developer carrying member), the generation of ghosts, and the change in φ5 image density are normal temperature normal humidity (N / N), normal temperature low humidity (N / L) And the following methods and standards under three environments of high temperature and high humidity (H / H), and reversal fog was evaluated under the following methods and standards in a room temperature and low humidity (N / L) environment. .
[0035]
▲ 1 ▼ Blotch
The solid black and halftone images obtained by the image drawing test were visually observed, and the blotch was evaluated on the basis of the following criteria for the images after 1, 1000 and 100,000 images. As a result, good results were obtained as shown in Table 2.
A: Excellent
○: Good
Δ: Normal
×: Bad
[0036]
(2) Ghost
The halftone image of the ghost chart obtained by the image drawing test was visually observed, and the ghost was evaluated with respect to the image after 1, 1000 and 100,000 images according to the following criteria. As a result, good results were obtained as shown in Table 3.
A: Excellent
○: Good
Δ: Normal
×: Bad
[0037]
(3) φ5 image density
For φ5 images, after printing 1 image, 50,000 images, 100,000 images, 150,000 images, 200,000 images, 250,000 images, and 300,000 images, The image density was measured with a reflection densitometer RD918 (manufactured by Macbeth), and the durability of the image density was examined. As a result, as shown in FIG. 3A, a stable image density was obtained for long-term durability.
[0038]
(4) Inverted fog
1 sheet, 10 sheets, 100 sheets, and 1000 sheets were printed out and examined for reversal fog. The reverse fog is 128 g / m in which an image is formed by setting the density correction key of the copying machine main body to be the lightest density. ² Reflectivity of solid white part of thick paper (D ₁ ), And the reflectance (D of unused cardboard that has the same cut as the cardboard used for image formation) ₂ ) And D ₂ -D ₁ The five values were obtained, and the average value was taken as the fog density. The reflectance at that time was measured with TC-6DS (manufactured by Tokyo Denshoku). As a result, good results were obtained as shown in FIG.
[0039]
(5) Tribo
The measurement of the suction method tribo value on the developer carrying member was carried out by the following method. That is, the developer layer on the surface of the developer carrying member immediately after image formation (within 5 minutes) using a measuring container having a cylindrical filter paper attached with a metal suction port along the shape of the surface of the developer carrying member. The developer on the surface of the developer carrying member is sucked by adjusting the suction pressure so that the toner can be sucked uniformly without excess or deficiency. The charge Q of the developer sucked at this time is measured with a 616 digital electrometer (manufactured by KEITHLEY), the mass M of the developer is measured, and the tribo value of the developer is calculated by Q / M (mC / kg). Calculated. The measurement was performed after 1000 sheets. As a result, good results were obtained as shown in Table 1.
[0040]
▲ 6 ▼ White streaks
The solid black and halftone images obtained by the image drawing test were visually observed, and the white streaks of the images after 1, 1000 and 100,000 images were evaluated according to the following criteria. As a result, good results were obtained as shown in Table 4.
A: Excellent
○: Good
Δ: Normal
×: Bad
[0041]
(Example 2)
The same as Example 1 except that the quaternary ammonium salt compound represented by the following formula (2) was used instead of the quaternary ammonium salt compound represented by the formula (1) used in Example 1. A paint-like resin composition was obtained by the following formulation and operation. The quaternary ammonium salt compound represented by the following formula (2) was also positive as in Example 1 when the triboelectric charge amount with the iron powder was measured by the blow-off method.
Embedded image

[0042]
The composition of the obtained resin composition was C / GF / B / P = 0.2 / 0.8 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. This resin composition was applied, dried and cured on the same aluminum substrate as in Example 1 to produce a developing sleeve 2 having a conductive resin coating layer on the surface.
Furthermore, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 2. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0043]
(Example 3)
The same formulation as in Example 1 except that a quaternary ammonium salt compound represented by the following formula (3) was used instead of the quaternary ammonium salt compound of the formula (1) used in Example 1. By operation, a paint-like resin composition was obtained. The quaternary ammonium salt compound represented by the following formula (3) was also positive as in Example 1 when the triboelectric charge amount with the iron powder was measured by the blow-off method.
Embedded image

[0044]
The composition of the obtained resin composition was C / GF / B / P = 0.2 / 0.8 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. In the same manner as in Example 1, this resin composition was applied, dried and cured on an aluminum substrate to produce a developing sleeve 3 having a conductive resin coating layer on the surface.
Furthermore, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 3. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0045]
(Example 4)
The same formulation as in Example 1 except that a quaternary ammonium salt compound represented by the following formula (4) was used instead of the quaternary ammonium salt compound of the formula (1) used in Example 1. By operation, a paint-like resin composition was obtained. The quaternary ammonium salt compound represented by the following formula (4) was also positive as in Example 1 when the triboelectric charge with the iron powder was measured by the blow-off method.
Embedded image

[0046]
The composition of the obtained resin composition was C / GF / B / P = 0.2 / 0.8 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. This resin composition was applied, dried and cured on the same aluminum substrate as in Example 1 to produce a developing sleeve 4 having a conductive resin coating layer on the surface.
Furthermore, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 4. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0047]
(Example 5)
After mixing the following materials, using a zirconia particle of φ2 mm as a filler and dispersing for 3 hours in a sand mill, the zirconia particles are separated by sieving, and the solid content is adjusted to 30% with IPA. The resin composition which added the quaternary ammonium salt compound which is positively charged with respect to iron powder in resin was obtained.

[0048]
The resin composition obtained above is in the form of a paint, and the composition is C (carbon) / BN (boron nitride) / B (phenol resin) / P (quaternary ammonium salt compound) = 0. It was 2 / 1.6 / 2.5 / 0.5. For the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1. The value was as shown in Table 1.
Next, this resin composition is applied by spray method onto an aluminum cylinder of φ20 mm to form a 10 μm film, and then heated and cured at 150 ° C. for 30 minutes with a hot air drier on the surface. A developing sleeve 5 having a conductive resin coating layer was produced.
Furthermore, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 5. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0049]
(Example 6)
Instead of the quaternary ammonium salt compound of the formula (1) used in Example 5, the quaternary ammonium whose charging polarity with the iron powder represented by the formula (2) used in Example 2 is positive. In the same manner as in Example 5, except that a phenolic resin using trimethylamine as a catalyst is used instead of a phenolic resin prepared using a salt compound and hexamethylenetetramine as a catalyst, a paint-like resin is used. A composition was obtained.
The composition of the obtained resin composition was C / BN / B / P = 0.2 / 1.6 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. Using this resin composition, it was coated, dried and cured on the same aluminum substrate as in Example 5 to produce a developing sleeve 6 having a conductive resin coating layer on the surface.
Further, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 6. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0050]
(Example 7)
In place of the quaternary ammonium salt compound of the formula (1) used in Example 5, the quaternary ammonium salt compound of the formula (3) used in Example 3 is used, and further produced using hexamethylenetetramine as a catalyst. A paint-like resin composition was obtained by the same formulation and operation as in Example 5 except that a phenol resin using triethylamine as a catalyst was used instead of the phenol resin thus prepared.
The composition of the obtained resin composition was C / BN / B / P = 0.2 / 1.6 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. Using this resin composition, a developing sleeve 7 having a conductive resin coating layer on the surface was prepared by applying, drying and curing on the same aluminum substrate as in Example 5.
Further, using the developing sleeve 7 obtained, image output evaluation was performed in the same manner as in Example 1. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0051]
(Example 8)
In place of the quaternary ammonium salt compound of the formula (1) used in Example 5, the quaternary ammonium salt compound of the formula (4) used in Example 4 is used and further produced using hexamethylenetetramine as a catalyst. A paint-like resin composition was obtained by the same formulation and operation as in Example 5 except that a phenol resin using pyridine as a catalyst was used instead of the phenol resin thus prepared.
The composition of the obtained resin composition was C / BN / B / P = 0.2 / 1.6 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. Using this resin composition, it was applied, dried and cured on the same aluminum substrate as in Example 5 to produce a developing sleeve 8 having a conductive resin coating layer on the surface.
Further, using the obtained developing sleeve 8, image output evaluation was performed in the same manner as in Example 1. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0052]
Example 9
After mixing the following materials, using a zirconia particle of φ2 mm as a filler and dispersing for 3 hours in a sand mill, the zirconia particles are separated by sieving, and the solid content is adjusted to 35% with IPA. A resin composition having at least a resin and a quaternary ammonium salt compound that is positively charged with respect to iron powder was obtained.

The resin composition obtained above is in the form of a paint, and its composition is C (carbon) / MoS. ₂ (Molybdenum disulfide) / B (phenol resin) / P (quaternary ammonium salt compound) = 0.2 / 1.6 / 2.5 / 0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1.
[0053]
Next, this resin composition is applied by spray method onto an aluminum cylinder of φ20 mm to form a 10 μm film, and then heated and cured at 150 ° C. for 30 minutes with a hot air dryer, A developing sleeve 9 having a conductive resin coating layer was prepared.
Further, using the obtained developing sleeve 9, image output evaluation was performed in the same manner as in Example 1. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0054]
(Example 10)
Instead of the quaternary ammonium salt compound of the formula (1) used in Example 9, the quaternary which is positively charged in polarity with the iron powder represented by the formula (2) used in Example 2 In addition to using an ammonium salt compound and using a phenol resin using trimethylamine as a catalyst instead of a phenol resin produced using hexamethylenetetramine as a catalyst, the same procedure and operation as in Example 9 was followed. A resin composition was obtained.
The composition of the obtained resin composition was C / MoS. ₂ /B/P=0.2/1.6/2.5/0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. Using this resin composition, a developing sleeve 10 having a conductive resin coating layer on the surface was prepared by applying, drying and curing on the same aluminum substrate as in Example 9.
Furthermore, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 10. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0055]
(Example 11)
Instead of the quaternary ammonium salt compound of the formula (1) used in Example 9, the quaternary which is positively charged in polarity with the iron powder represented by the formula (3) used in Example 3 In the same formulation and operation as in Example 9, except that an ammonium salt compound was used and a phenol resin using triethylamine as a catalyst was used instead of the phenol resin produced using hexamethylenetetramine as a catalyst, A resin composition was obtained.
The composition of the obtained resin composition was C / MoS. ₂ /B/P=0.2/1.6/2.5/0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. Using this resin composition, a developing sleeve 11 having a conductive resin coating layer on its surface was prepared by applying, drying and curing on the same aluminum substrate as in Example 9.
Further, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 11. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0056]
(Example 12)
Instead of the quaternary ammonium salt compound of the formula (1) used in Example 9, the friction charge polarity with the iron powder represented by the formula (4) used in Example 4 is positive. In the same manner as in Example 9, except that a phenolic resin using a pyridine as a catalyst was used instead of a phenolic resin prepared using a quaternary ammonium salt compound and hexamethylenetetramine as a catalyst, A resin composition was obtained.
The composition of the obtained resin composition was C / MoS. ₂ /B/P=0.2/1.6/2.5/0.5. Further, for the paint-like resin composition used in this example, the volume resistance value was determined in the same manner as in Example 1, and the value was as shown in Table 1. Using this resin composition, it was applied, dried and cured on the same aluminum substrate as in Example 9 to produce a developing sleeve 12 having a conductive resin coating layer on the surface.
Furthermore, image development evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve 12. As a result, good results were obtained as shown in Table 2, Table 3, Table 4, and FIG.
[0057]
(Comparative Example 1)
The developing sleeve of Comparative Example 1 was obtained by sandblasting with FGB # 300 on the surface of an aluminum cylinder having a diameter of 20 mm similar to that used in the examples. Using this, image output evaluation was performed in the same manner as in Example 1. As a result, as shown in Tables 2 and 3, the blotch was so severe that it was impossible to evaluate other images.
[0058]
(Comparative Example 2)
A paint-like resin composition was obtained in the same manner as in Example 1 except that the following formulation was used. The obtained resin composition was in the form of a paint, and its composition was C / GF / B / P = 0.2 / 0.8 / 2.5 / 0.

Using this resin composition, a developing sleeve of Comparative Example 2 having a conductive resin coating layer on its surface was prepared by coating, drying and curing on the same aluminum substrate as in Example 1. Using this developing sleeve, image output was evaluated in the same manner as in Example 1. As a result, as shown in Table 2, Table 3, Table 4, and FIG. 15, the fog was only slightly worse at the initial stage, but a decrease in the image density in durability was observed. Further, the volume resistance value of the paint-like resin composition used in this comparative example was determined in the same manner as in Example 1, and the value was as shown in Table 1.
[0059]
(Comparative Example 3)
Resin composition in the same formulation and operation as in Example 1 except that instead of the quaternary ammonium salt compound of formula (1) used in Example 1, a chromium complex (S) of azonaphthol containing chlorophenol was used. A product was made. The composition of the obtained resin composition was C / GF / B / S = 0.2 / 0.8 / 2.5 / 0.5. Here, when the triboelectric charge amount of the azonaphthol chromium complex (S) containing chlorophenol and the iron powder was measured by the blow-off method in the same manner as in Example 1, it was negative. Further, the volume resistance value of the paint-like resin composition used in this comparative example was determined in the same manner as in Example 1, and the value was as shown in Table 1.
Using this resin composition, a developing sleeve of Comparative Example 3 having a conductive resin coating layer on its surface was prepared by coating, drying and curing on the same aluminum substrate as in Example 1.
Furthermore, image output evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve. As a result, as shown in Table 2, Table 3, Table 4, and FIG. 16, the fog was poorly fogged up to about 50 sheets, and the durability and the image density decreased.
[0060]
(Comparative Example 4)
A resin composition was prepared in the same formulation and operation as in Example 1, except that nigrosine (N) was used instead of the quaternary ammonium salt compound of formula (1) used in Example 1. The composition of the obtained resin composition was C / GF / B / N = 0.2 / 0.8 / 2.5 / 0.5). Here, when the triboelectric charge amount of nigrosine with the iron powder was measured by the blow-off method in the same manner as in Example 1, it was positive. Further, the volume resistance value of the paint-like resin composition used in this comparative example was determined in the same manner as in Example 1, and the value was as shown in Table 1.
Using this resin composition, a developing sleeve of Comparative Example 3 having a conductive resin coating layer on its surface was prepared by coating, drying and curing on the same aluminum substrate as in Example 1.
Furthermore, image output evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve. As a result, as shown in Table 2, Table 3, Table 4 and FIG. 17, the fogging was poor up to about 1000 sheets, and the image density was lowered at the early stage of durability.
[0061]
(Comparative Example 5)
Resin composition with the same formulation and operation as in Example 1 except that the quaternary ammonium salt compound of the following formula (9) was used instead of the quaternary ammonium salt compound of the formula (1) used in Example 1. I got a thing. The composition of the obtained resin composition was C / GF / B / P = 0.2 / 0.8 / 2.5 / 0.5. Regarding the quaternary ammonium salt compound of the following formula (9), the triboelectric charge amount with the iron powder was measured by the blow-off method in the same manner as in Example 1. However, unlike Example 1, it was negative. Further, the volume resistance value of the paint-like resin composition used in this comparative example was determined in the same manner as in Example 1, and the value was as shown in Table 1.
Embedded image

Using this resin composition, a developing sleeve of Comparative Example 5 having a conductive resin coating layer on the surface was prepared by coating, drying and curing on the same aluminum substrate as in Example 1.
Furthermore, image output evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve. As a result, as shown in Table 2, Table 3, Table 4, and FIG. 18, fog was good after 10 sheets, but a decrease in image density was observed.
[0062]
(Comparative Example 6)
In Example 1, a resin composition was obtained by the same formulation and operation as in Example 1 except that PMMA resin was used instead of phenol produced using ammonia as a catalyst. The composition of the obtained resin composition was C / GF / B / P = 0.2 / 0.8 / 2.5 / 0.5. Further, the volume resistance value of the paint-like resin composition used in this comparative example was determined in the same manner as in Example 1, and the value was as shown in Table 1.
Using this resin composition, a developing sleeve of Comparative Example 6 having a conductive resin coating layer on the surface was produced by applying, drying and curing on the same aluminum substrate as in Example 1.
Furthermore, image output evaluation was performed in the same manner as in Example 1 using the obtained developing sleeve. As a result, as shown in Table 2, Table 3, Table 4, and FIG. 19, the fog was bad up to 1000 sheets, and the image density was bad from the beginning.
[0063]
Table 1: Composition of developer carrier

Note) * 1: Frictional charge polarity against iron powder
[0064]
Table 2: Evaluation result (blotch)

[0065]
Table 3: Evaluation results (ghost)

[0066]
Table 4: Evaluation results (white stripes)

[0067]
【The invention's effect】
As described above, according to the present invention, as the material for forming the coating layer provided on the outer periphery of the developer carrier, the conductive material, the phenol resin, and the iron powder itself are positively charged. By using a resin composition containing at least a quaternary ammonium salt compound, when the above resin composition is heated and cured to form a phenol resin film, unlike the case where a conventional charge imparting particle is added, Since the quaternary ammonium salt compound is not dispersed in the phenol resin but is incorporated in the structure thereof, the wear resistance of the coating layer is remarkably improved and it can withstand long-term durability.
[0068]
Furthermore, according to the present invention, since the coating layer provided on the outer periphery of the developer carrying member is formed by incorporating a quaternary ammonium salt compound into the structure of the phenol resin, the positively chargeable toner of the phenol resin itself. Improves positive triboelectric chargeability to a developer having
Therefore, by using the above resin composition as a binder resin material for a conductive coating layer formed on the surface of a developer carrier using a developer having a positively chargeable toner, charge imparting property to the developer is achieved. And the wear resistance of the coating layer is improved. As a result, it is possible to obtain a high-quality image over a long period of time, not only under normal temperature and normal humidity, but also under high temperature and high humidity and low humidity, such as image density reduction, ghost, blotch and solid fog. It is possible to provide a stable and high-quality image.
[0069]
Further, in the present invention, since a phenol resin is used as the binder resin for forming the coating layer provided on the outer periphery of the developer carrier, Teflon having a positive triboelectric charge-providing property for a developer having a positively chargeable toner, etc. Compared to a resin that is hardly soluble in various solvents, it is easier to apply to a developer carrier.
[Brief description of the drawings]
FIG. 1 is a schematic partial cross-sectional view showing an example of a developer carrier in the present invention.
FIG. 2 is a schematic diagram illustrating an example of a developing device of the present invention.
3 is a graph showing a durable image density transition and a fog transition of Example 1. FIG.
4 is a graph showing a durable image density transition and a fog transition of Example 2. FIG.
5 is a graph showing a durable image density transition and a fog transition of Example 3. FIG.
6 is a graph showing a durable image density transition and a fog transition of Example 4. FIG.
7 is a graph showing a durable image density transition and a fog transition of Example 5. FIG.
8 is a graph showing a durable image density transition and a fog transition of Example 6. FIG.
9 is a graph showing a durable image density transition and a fog transition of Example 7. FIG.
10 is a graph showing a durable image density transition and a fog transition of Example 8. FIG.
11 is a graph showing a durable image density transition and a fog transition of Example 9. FIG.
12 is a graph showing a durable image density transition and a fog transition of Example 10. FIG.
13 is a graph showing a durable image density transition and a fog transition of Example 11. FIG.
14 is a graph showing a durable image density transition and a fog transition of Example 12. FIG.
15 is a graph showing a durable image density transition and a fog transition of Comparative Example 2. FIG.
16 is a graph showing a durable image density transition and a fog transition of Comparative Example 3. FIG.
17 is a graph showing a durable image density transition and a fog transition of Comparative Example 4. FIG.
18 is a graph showing a durable image density transition and a fog transition of Comparative Example 5. FIG.
FIG. 19 is a graph showing a durable image density transition and a fog transition of Comparative Example 6;
[Explanation of symbols]
1: Coating layer
2: Conductive substance
3: Binder resin
4: Solid lubricant
5: Cylindrical substrate
7: Photosensitive drum
8: Regulatory blade
9: Hopper
10: Toner
11: Magnet
12: Cylindrical substrate
13: Coating layer
14: Development sleeve
15: Power supply
16: Stirrer
17: Elastic plate
A: Direction of rotation of developing sleeve
B: Direction of rotation of the photosensitive drum
D: Development part

Claims (6)

A developer having a positively charged toner contained in a developer container is carried on a developer carrying member, and a developer thin layer is formed on the developer carrying member by a developer layer thickness regulating member while developing. In a developing device for transporting a developer to a development area where the agent carrier and the latent image carrier are opposed to each other, and developing the latent image on the latent image carrier with a developer to make a visible image,
A resin coating layer formed of a resin composition containing at least a conductive substance, a phenol resin, and a quaternary ammonium salt compound that is positively charged with respect to iron powder on the surface of the developer carrying member. A developing device provided.   The developing device according to claim 1, wherein the phenol resin is a phenol resin produced using a nitrogen-containing compound as a catalyst. A developer having a positively charged toner contained in a developer container is carried on a developer carrying member, and a developer thin layer is formed on the developer carrying member by a developer layer thickness regulating member while developing. A developer used in a developing device that transports a developer to a developing area where the agent carrier and the latent image carrier are opposed to each other, and develops the latent image on the latent image carrier with the developer to make a visible image. A carrier,
A resin coating layer formed of a resin composition containing at least a conductive substance, a phenol resin, and a quaternary ammonium salt compound that is positively charged with respect to iron powder is provided on the surface. A developer carrying member. The developer carrying member according to claim 3, wherein the phenol resin is a phenol resin produced using a nitrogen-containing compound as a catalyst. A developer having a positively charged toner contained in a developer container is carried on a developer carrying member, and a developer thin layer is formed on the developer carrying member by a developer layer thickness regulating member while developing. In the developing method of transporting the developer to a development area where the agent carrier and the latent image carrier are opposed to each other, and developing the latent image on the latent image carrier with the developer to make a visible image,
A resin coating layer formed of a resin composition containing at least a conductive substance, a phenol resin, and a quaternary ammonium salt compound that is positively charged with respect to iron powder on the surface of the developer carrying member. A developing method characterized by being provided.   The developing method according to claim 5, wherein the phenol resin is a phenol resin produced using a nitrogen-containing compound as a catalyst.

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