JP4035279B2 - Developing method, developing device, and image forming apparatus - Google Patents

Description

（式中のＲ^１、Ｒ^２、Ｒ^３、Ｒ^４は、各々、置換基を有しても良いアルキル基、置換基を有しても良いアリール基、アルアルキル基を表し、Ｒ^１〜Ｒ^４は各々同一でもあるいは異なっていてもよい。Ｘ⁻は酸の陰イオンを表す。）
これに対し、例えば下記式（２）で表されるような、鉄粉に対して負帯電性を有する含フッ素４級アンモニム塩化合物についても検討を行ったが、該化合物の添加では、本発明の所期の目的が達成されないことがわかった。下記式（２）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鉄粉に対して負帯電性を有する。本発明の場合と同様に、該化合物を被覆層用結着樹脂に分散させた樹脂組成物を加熱乾燥させてキャリア芯材に樹脂被覆層を形成した現像剤担持体を用いても、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ほどには、効果は得られなかった。
【００３３】
【化２】

また、前記シリカ粉の添加や代表的な負帯電制御剤である３，５−ジ−ｔ−ブチルサリチル酸のＣｒ錯体を被覆層用結着樹脂中に添加したものを現像剤担持体の樹脂被覆層に用いても本発明に相応する効果は得られなかった。
【００３４】
本発明に好適に用いられる、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、下記式（３）〜（１０）の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。
【００３５】
【化３】

【００３６】
【化４】

【００３７】
【化５】

【００３８】
【化６】

【００３９】
【化７】

【００４０】
【化８】

【００４１】
【化９】

【００４２】
【化１０】

本発明における現像剤担持体の樹脂被覆層に使用する上記に示したような第４級アンモニウム塩化合物の添加量は、被覆層用結着樹脂１００質量部に対して１〜２００質量部とすることが好ましい。より好ましくは、被覆層用結着樹脂１００質量部に対して２〜１００質量部である。１質量部未満では添加による帯電性制御の効果が見られず、２００質量部を超えると被覆層用結着樹脂中での存在量が過剰となって元の樹脂の特性を損ない被膜強度の低下を招きやすい。
【００４３】
本発明の被覆層に用いられる被覆層用結着樹脂としては、特に限定はされないが、被覆層用結着樹脂の一部又は全部がその分子構造中に少なくとも−ＮＨ₂基、＝ＮＨ基、もしくは−ＮＨ−結合のいずれかの構造を有していることが好ましい。このような樹脂を用いて被覆層を形成することで、本発明の効果が容易に発揮可能である。本発明において、現像剤担持体の樹脂被覆層として上記のような構成のものを用いると、樹脂被覆層自身が負帯電付与性へと変化することについての明確な理由は定かではないが、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及び、−ＮＨ₂基、＝ＮＨ基、もしくは−ＮＨ−結合の少なくとも一つの構造を有している被覆層用結着樹脂を用いて樹脂被覆層を形成することにより被覆層用結着樹脂の構造中に第４級アンモニウム塩が取り込まれる。その際、正極性を有する第４級アンモニウム塩の元の構造が失われ、これらを取り込んだ被覆層用結着樹脂の帯電性が均一且つ十分な負帯電性を有するようになり帯電の安定化に寄与するためではないかと考えられる。
【００４４】
−ＮＨ₂基を有する物質としては、Ｒ−ＮＨ₂で表される第１アミンもしくはそれらを有するポリアミン、ＲＣＯ−ＮＨ₂で表される第１アミドもしくはそれらを有するポリアミド等、＝ＮＨ基を有する物質としては、Ｒ＝ＮＨで表される第２アミンもしくはそれらを有するポリアミン、（ＲＣＯ）₂＝ＮＨで表される第２アミドもしくはそれらを有するポリアミド等、−ＮＨ−結合を有する物質としては、前述したポリアミン、ポリアミド等の他に−ＮＨＣＯＯ−結合を有するポリウレタン等が挙げられ、以上の物質を１種又は２種以上、あるいは共重合体として含有し、工業的に合成された樹脂が好適に用いられる。具体的には、汎用性等の面から、触媒として含窒素化合物を用いて、フェノール類とアルデヒド類を付加・縮合させて製造したフェノール樹脂、ポリアミド樹脂あるいはウレタン樹脂等が特に好ましい。
【００４５】
本発明で触媒として用いられる含窒素化合物としては、酸性触媒と塩基性触媒が挙げられ、酸性触媒としては、例えば、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等のアンモニウム塩またはアミン塩類が挙げられる。塩基性触媒としては、例えば、アンモニア、或いはジメチルアミン、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、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が挙げられる。
【００４６】
その他の被覆層用結着樹脂材料としては、一般に公知の樹脂が使用可能である。例えば、スチレン系樹脂、ビニル系樹脂、ポリエーテルスルホン樹脂、ポリカーボネート樹脂、ポリフェニレンオキサイド樹脂、ポリアミド樹脂、フッ素樹脂、繊維素系樹脂、アクリル系樹脂等の熱可塑性樹脂、エポキシ樹脂、ポリエステル樹脂、アルキッド樹脂、フェノール樹脂、メラミン樹脂、ポリウレタン樹脂、尿素樹脂、シリコーン樹脂、ポリイミド樹脂等の熱あるいは光硬化性樹脂等を使用することができる。なかでもシリコーン樹脂、フッ素樹脂のような離型性のあるもの、或いはポリエーテルスルホン、ポリカーボネート、ポリフェニレンオキサイド、ポリアミド、フェノール、ポリエステル、ポリウレタン、スチレン系樹脂、アクリル系樹脂のような機械的性質に優れたものがより好ましい。ただし、本発明の構成を容易に達成するためには、前述のごとく、−ＮＨ_２基、＝ＮＨ基、もしくは−ＮＨ−結合の少なくとも一つの構造を有している被覆層用結着樹脂を用いることが好ましい。また、−ＮＨ_２基、＝ＮＨ基、もしくは−ＮＨ−結合の少なくとも一つの構造を有している被覆層用結着樹脂を上記一般的な被覆層用結着樹脂と混合して用いることも可能である。
【００４７】
本発明に用いられる現像剤担持体は該樹脂被覆層の体積抵抗を調整する為、被覆層用結着樹脂中に導電性微粉末を分散含有させても良い。このような導電性微粉末としては、個数平均粒径が２０μｍ以下が好ましく、１０μｍ以下がより好ましい。樹脂表面に形成される凹凸を避けるためには、個数平均粒径１μｍ以下のものを用いる。
【００４８】
本発明で使用される導電性微粉末としては、ファーネスブラック、ランプブラック、サーマルブラック、アセチレンブラック、チャンネルブラック等のカーボンブラック；酸化チタン、酸化スズ、酸化亜鉛、酸化モリブデン、チタン酸カリウム、酸化アンチモン及び酸化インジウム等の金属酸化物等；アルミニウム、銅、銀、ニッケル等の金属；グラファイト、金属繊維、炭素繊維等の無機系充填剤等が挙げられる。上述した樹脂被覆層中の導電性微粉末の添加量としては、被覆層用結着樹脂１００質量部に対して２００質量部以下の範囲が好ましい結果を与える。より好ましい添加量は、１００質量部以下である。添加量が２００質量部を越えると被膜強度の低下が起こり易く、また多量の導電性微粉末の添加は、現像剤の帯電量の低下が生じうる。
【００４９】
本発明に用いられる現像剤担持体の樹脂被覆層は、潤滑性物質を被覆樹脂層中に分散させることで、より本発明の効果が促進されるので好ましい。潤滑性物質としては、例えばグラファイト、二硫化モリブデン、窒化硼素、雲母、フッ化グラファイト、銀−セレン化ニオブ、塩化カルシウム−グラファイト、滑石、ステアリン酸亜鉛等の脂肪酸金属塩等が挙げられ、特にグラファイトが被覆層の導電性を損なわないので好ましく用いられる。これらの潤滑性物質は、個数平均粒径が好ましくは０．２〜２０μｍ程度、より好ましくは０．３〜１５μｍのものを使用するのがよい。上記潤滑性物質の添加量としては、被覆層用結着樹脂１００質量部に対して１０〜１２０質量部の範囲で特に好ましい結果を与える。添加量が１２０質量部を越える場合は被膜強度の低下が生じ易く、また非帯電性の添加物を多量に添加することは、現像剤の帯電量の低下が発生する。逆に１０質量部未満では現像剤担持体への現像剤付着防止に対する添加効果を得られにくい。
【００５０】
次に本発明に用いられる現像剤担持体の構成について説明する。
【００５１】
現像剤担持体は基体と、それを取り巻いて被覆する樹脂被覆層とからなる。基体の形状としては、円筒状部材、円柱状部材、ベルト状部材等がある。ドラムに非接触の現像方法においては円筒状部材が好ましく用いられ、具体的には金属製の円筒管が好ましく用いられる。前記金属は、主としてステンレススチール、アルミニウムおよびその合金等の非磁性のものが好適に用いられる。また、ドラムに直接接触させる現像方法の場合の基体としては、ウレタン、ＥＰＤＭ、シリコーン等のゴムやエラストマーを含む層構成を有する円筒状部材が好ましく用いられる。
【００５２】
また、磁性現像剤を用いる場合は、現像剤を現像剤担持体上に磁気的に吸引かつ保持するために、磁石が内設されているマグネットローラ等を現像剤担持体内に配置する。その場合、基体を円筒状としその内部にマグネットローラを配置すればよい。一方、非磁性現像剤を用いる場合は、磁石を内包する必要はない。
【００５３】
現像剤担持体の樹脂被覆層は、前述した導電性微粉末、潤滑性物質等の添加物質に加えて、個数平均粒径が０．３〜３０μｍの球状粒子を被覆樹脂層中に分散させることも好ましい。それによって、表面粗さを安定化させ、現像剤担持体上の現像剤のコート量を最適化することが可能である。該球状粒子は、現像剤担持体の樹脂被覆層表面に均一な表面粗度を保持させると同時に、樹脂被覆層表面が摩耗した場合でも樹脂被覆層の表面粗度の変化が少なく、且つ現像剤汚染や現像剤融着を発生しにくくする効果がある。
【００５４】
本発明に使用される球状粒子としては、個数平均粒径が０．３〜３０μｍ、好ましくは２〜２０μｍである。球状粒子の個数平均粒径が０．３μｍ未満では表面に均一な粗さを付与する効果とそれにより帯電性能を安定化させる効果が少なく、現像剤への迅速且つ均一な帯電が不十分となる傾向がある。さらに、現像剤の搬送が不安定となることや、被覆層の磨耗による搬送性のさらなる低下で現像剤のチャージアップ、現像剤汚染及び現像剤融着が発生し、ゴーストの悪化、画像濃度低下を生じやすくなるため好ましくない。個数平均粒径が３０μｍを越える場合には、被覆層表面の粗さが大きくなり過ぎ、現像剤の搬送量が大きくなり、現像剤規制部での規制が十分に行われにくくなり、現像剤の帯電が十分に行われにくくなって画質の低下反転カブリの増加など不具合が起こる。さらには、被覆層の機械的強度が低下し膜の耐久性が低下するため好ましくない。
【００５５】
さらに好ましくは、球状粒子の真密度は、３ｇ／ｃｍ³以下、好ましくは２．７ｇ／ｃｍ³以下、より好ましくは０．９〜２．３ｇ／ｃｍ³であることが良い。即ち、球状粒子の真密度が３ｇ／ｃｍ³を越える場合には、被覆層中での球状粒子の分散性が不十分となる為、被覆層表面に均一な粗さを付与しにくくなる。また、塗料の保存安定性が良くないため、ここでも均一表面凹凸を有する摩擦帯電付与部材表面が得にくくなる。球状粒子の真密度が０．９ｇ／ｃｍ³より小さい場合にも、被覆層中での球状粒子の分散性および保存安定性が不十分となる。
【００５６】
本発明に於いて、球状粒子における球状とは、粒子の長径／短径の比が１．０〜１．５程度の物を意味しており、本発明において好ましくは、長径／短径の比が１．０〜１．２の粒子を使用することが良い。球状粒子の長径／短径の比が１．５を越える場合には、被覆層表面粗さの不均一化が発生し、現像剤の迅速且つ均一な帯電化及び導電性樹脂被覆層の強度の点で好ましくない。
【００５７】
本発明に用いられる球状粒子は、公知の球状粒子が使用可能である。例えば、球状の樹脂粒子、球状の金属酸化物粒子、球状の炭素化物粒子などがある。球状の粒子としては、例えば、懸濁重合、分散重合法等によって製造された球状の樹脂粒子などが用いられる。球状の樹脂粒子は、より少ない添加量で好適な表面粗さが得られ、更に均一な表面形状が得られやすい。球状の樹脂粒子として具体的には、ポリアクリレート、ポリメタクリレート等のアクリル系樹脂粒子、ナイロン等のポリアミド系樹脂粒子、ポリエチレン、ポリプロピレン等のポリオレフィン系樹脂粒子、シリコーン系樹脂粒子、フェノール系樹脂粒子、ポリウレタン系樹脂粒子、スチレン系樹脂粒子、ベンゾグアナミン粒子等が挙げられる。また、粉砕法により得られた樹脂粒子を熱的にあるいは物理的な球形化処理を行ってから用いてもよい。
【００５８】
また、該球状粒子の表面に無機微粉体を付着させる、あるいは固着させて用いてもよい。この様な無機微粉体としては、ＳｉＯ₂，ＳｒＴｉＯ₃，ＣｅＯ₂，ＣｒＯ，Ａｉ₂Ｏ₃，ＺｎＯ，ＭｇＯ等の酸化物、Ｓｉ₃Ｎ₄等の窒化物、ＳｉＣ等の炭化物、ＣａＳＯ₄，ＢａＳＯ₄，ＣａＣＯ₃等の硫酸塩、炭酸塩等が挙げられる。このような無機微粉体は、カップリング剤により処理して用いても良い。無機微粉体をカップリング剤処理することにより、球状粒子を被覆層用結着樹脂との密着性を向上させたり、球状粒子に疎水性を与えたりすることができる。
【００５９】
このようなカップリング剤としては、例えば、シランカップリング剤、チタンカップリング剤、ジルコアルミネートカップリング剤等がある。より具体的には、例えばシランカップリング剤としては、ヘキサメチルジシラザン、トリメチルシラン、トリメチルクロルシラン、トリメチルエトキシシラン、ジメチルジクロルシラン、メチルトリクロルシラン、アリルジメチルクロルシラン、アリルフェニルジクロルシラン、ベンジルジメチルクロルシラン、ブロムメチルジメチルクロルシラン、α−クロルエチルトリクロルシラン、β−クロルエチルトリクロルシラン、クロルメチルジメチルクロルシラン、トリオルガノシリルメルカプタン、トリメチルシリルメルカプタン、トリオルガノシリルアクリレート、ビニルジメチルアセトキシシラン、ジメチルジエトキシシラン、ジメチルジメトキシシラン、ジフェニルジエトキシシラン、ヘキサメチルジシロキサン、１，３−ジビニルテトラメチルジシロキサン、１，３−ジフェニルテトラメチルジシロキサン及び１分子当たり２から１２個のシロキサン単位を有し末端に位置する単位にそれぞれ１個宛の硅素原子に結合した水酸基を含有したジメチルポリシロキサン等が挙げられる。
【００６０】
このように球状粒子表面に対して無機微粉体で処理することにより、被覆層中への分散性、被覆層表面の均一性、被覆層の耐汚染性、現像剤への帯電付与性、被覆層の耐磨耗性等を向上させることができる。
【００６１】
また、本発明に使用する球状粒子は、導電性であることが好ましい。即ち、球状粒子に導電性を持たせることによって、その導電性のゆえに粒子表面にチャージが蓄積しにくく、現像剤付着の軽減や現像剤への帯電付与性を向上させることができるからである。本発明において、球状粒子の導電性としては、体積抵抗値が１０^６Ω・ｃｍ以下、より好ましくは１０^−３〜１０^６Ω・ｃｍの粒子であることが好ましい。球状粒子の体積抵抗値が１０^６Ω・ｃｍを超えると、摩耗によって被覆層表面に露出した球状粒子を核として現像剤の汚染や融着を発生しやすくなるとともに、迅速且つ均一な帯電が行われにくくなるため、好ましくない。
【００６２】
このような導電性球状粒子を得る方法としては、以下に示す様な方法が好ましいが、必ずしもこれらの方法に限定されるものではない。
【００６３】
本発明に使用される特に好ましい導電性球状粒子を得る方法としては、例えば、樹脂系球状粒子やメソカーボンマイクロビーズを焼成して炭素化及び／又は黒鉛化して得た低密度且つ良導電性の球状炭素粒子を得る方法が挙げられる。樹脂系球状粒子に用いられる樹脂としては、例えば、フェノール樹脂、ナフタレン樹脂、フラン樹脂、キシレン樹脂、ジビニルベンゼン重合体、スチレン−ジビニルベンゼン共重合体、ポリアクリロニトリル等が挙げられる。また、メソカーボンマイクロビーズは、通常、中ピッチを加熱焼成していく過程で生成する球状結晶を多量のタール、中油、キノリン等の溶剤で洗浄することによって製造することができる。
【００６４】
より好ましい導電性球状粒子を得る方法としては、フェノール樹脂、ナフタレン樹脂、フラン樹脂、キシレン樹脂、ジビニルベンゼン重合体、スチレン−ジビニルベンゼン共重合体、ポリアクリロニトリル等の球状樹脂粒子表面に、メカノケミカル法によってバルクメソフェーズピッチを被覆し、被覆された粒子を酸化性雰囲気化で熱処理した後に不活性雰囲気下又は真空下で焼成して炭素化及び／又は黒鉛化し、導電性球状炭素粒子を得る方法が挙げられる。この方法で得る球状炭素粒子は、黒鉛化すると得られる球状炭素粒子の被覆部の結晶化が進んだものとなるので導電性が向上し、より好ましい。
【００６５】
上記した方法で得られる導電性の球状炭素粒子は、いずれの方法でも、焼成条件を変化させることによって、得られる球状炭素粒子の導電性を制御することが可能であり、本発明において好ましく使用される。又、上記の方法で得られる球状炭素粒子は、場合によっては、更に導電性を高めるために導電性球状粒子の真密度が３ｇ／ｃｍ³を越えない範囲で、導電性の金属及び／または金属酸化物のメッキを施していても良い。
【００６６】
本発明で使用される導電性球状粒子を得る他の方法としては、球状の樹脂粒子からなる芯粒子に対して、芯粒子の粒径より小さい粒径の導電性微粒子を適当な配合比で機械的に混合することによって、ファンデルワールス力及び静電気力の作用により、芯粒子の周囲に均一に導電性微粒子を付着した後、例えば機械的衝撃力を付与することによって生ずる局部的温度上昇により芯粒子表面を軟化させ、芯粒子表面に導電性微粒子を成膜して導電化処理した球状樹脂粒子を得る方法が挙げられる。
【００６７】
本発明に使用される導電性球状粒子を得る更に他の方法としては、球状樹脂粒子中に導電性微粒子を均一に分散させることにより、導電性微粒子が分散された導電性球状粒子を得る方法が挙げられる。球状樹脂粒子中に導電性微粒子を均一に分散させる方法としては、例えば、球状粒子用の結着樹脂と導電性微粒子とを混練して導電性微粒子を分散させた後、冷却固化し、所定の粒径に粉砕し、機械的処理及び熱的処理により球形化して導電性球状粒子を得る方法；又は、球状粒子用の重合性単量体中に重合開始剤、導電性微粒子及びその他の添加剤を加え、分散機によって均一に分散させた単量体組成物を、分散安定剤を含有する水相中に攪拌機等によって所定の粒子径になるように懸濁させて重合を行い、導電性微粒子が分散された球状粒子を得る方法；が挙げられる。
【００６８】
本発明の樹脂被覆層を形成する方法については、特に限定されず、通常の方法によって行える。例えば、現像剤担持体の基体に、上記被覆層用結着樹脂及び上記第４級アンモニウム塩化合物等を含有する塗布液をディッピング法、スプレー法、はけ塗り法などの方法で塗布し乾燥させれば、本発明の現像剤担持体が得られる。
【００６９】
本発明に用いられる現像剤は、結着樹脂および着色剤を少なくとも有し、且つ、フロー式粒子像測定装置で計測される平均円形度が０．９２０〜０．９９５であり、円形度標準偏差が０．０４５以下である。
【００７０】
また、フォロー式粒子像測定装置で計測される個数基準の円相当径−円形度スキャッタグラムにおける円相当個数平均径Ｄ１は２〜１０μｍである。
【００７１】
本発明における現像剤の円相当径、円形度及びそれらの粒度分布は、現像剤粒子の形状を定量的に表現する簡便な方法として用いたものであり、本発明では東亜医用電子（株）製フロー式粒子像測定装置ＦＰＩＡ−１０００型を用いて測定を行い、下式（I）および下式（II）を用いて算出したものである。
【００７２】
【数１】

ここで粒子投影面積とは二値化された現像剤粒子像の面積であり、粒子投影像の周囲長とは該現像剤粒子像のエッジ点を結んで得られる輪郭線の長さと定義する。
【００７３】
本発明における円形度は現像剤粒子の凹凸の度合いを示す指標であり、現像剤粒子が完全な球形の場合に１．０００を示し、表面形状が複雑になる程、円形度は小さな値となる。
【００７４】
本発明において、現像剤の個数基準の粒径頻度分布の平均値を意味する円相当個数平均径Ｄ１と粒径標準偏差ＳＤｄは、粒度分布の分割点ｉでの粒径（中心値）をｄｉ、頻度をｆｉとすると次式（III）と式（IV）から算出される。
【００７５】
【数２】

また、円形度頻度分布の平均値を意味する平均円形度ｃと円形度標準偏差ＳＤｃは、粒度分布の分割点ｉでの円形度（中心値）をｃｉ、頻度をｆｃｉとすると、次式（V）、（VI）から計算される。
【００７６】
【数３】

具体的な測定法としては、容器中に予め不純固形物などを除去したイオン交換水１０ｍｌを用意し、その中に分散剤として界面活性剤、好ましくはアルキルベンゼンスルホン酸塩を加えた後、更に測定試料（現像剤）を０．０２ｇを加え、均一に分散させる。分散させる手段としては、超音波分散機「ＵＨ−５０型」（エスエムテー社製）に振動子として直径５ｍｍのチタン合金チップを装着したものを用い、５分間分散処理を用い、測定用の分散液とする。その際、該分散液の温度が４０℃以上とならない様に適宜冷却する。
【００７７】
現像剤粒子の形状測定には、前記フロー式粒子像測定装置を用い、測定時の現像剤粒子濃度が３０００〜１万個／μｌとなる様に該分散液濃度を再調整し、現像剤粒子を１０００個以上計測する。計測後、このデータを用いて、現像剤粒子の円相当径や円形度頻度分布等を求める。
【００７８】
従来、１．０μｍ以下の粒径を測定可能な装置はいくつか存在するが、１．０μｍ以下の領域はノイズが大きく影響し、データの再現性に問題がある。この装置は１．０μｍ以下の領域でも再現性が良く、また実際に粒子画像としての情報が同時に得られるため、粒子の確認もできるという点で優れている。
【００７９】
フロー式粒子像測定装置で計測される該現像剤の個数基準の円相当径−円形度スキャッタグラムにおいて、該現像剤の円相当個数平均径Ｄ１が２〜１０μｍであり、且つ、該現像剤の平均円形度が０．９２０〜０．９９５で、円形度標準偏差が０．０４０未満が好ましい。より好ましくは平均円形度が０．９６５〜０．９９０で、円形度標準偏差が０．０３５未満であることが良い。前記フロー式粒子像測定装置で計測される現像剤の個数基準の円相当径−円形度スキャッタグラムにおいて、該現像剤が円形度０．９５０未満の現像剤粒子が１５個数％以下であることが好ましい。
【００８０】
現像剤の円相当個数平均径Ｄ１を２〜１０μｍと小粒径化することにより、画像の輪郭部分、特に文字画像やラインパターンの現像での再現性が良好なものとなる。しかし、一般に現像剤粒子を小粒径化すると必然的に微小粒子の現像剤の存在率が高くなるため、現像剤を均一に帯電させることが困難となり画像カブリを生じるばかりか、静電潜像担持体表面や現像剤担持体への付着力が高くなりやすい。
【００８１】
本発明に用いる現像剤を製造する方法は、特に制限はないが、特公昭３６−１０２３１号公報、特開昭５９−５３８５６号公報、特開昭５９−６１８４２号公報に述べられている懸濁重合法を用いて直接現像剤を生成する方法、単量体には可溶な水溶性重合開始剤の存在下で直接重合させて現像剤粒子を生成するソープフリー重合法に代表される乳化重合法による現像剤粒子の製造が挙げられる。また、マイクロカプセル製法のような界面重合法、in site重合法、コアセルベーション法などの製造も挙げられる。さらに、特開昭６２−１０６４７３号公報や特開昭６３−１８６２５３号公報に開示されているような、少なくとも１種以上の微粒子を凝集させ所望の粒径のものを得る界面重合法なども挙げられる。これらの中で小粒径の現像剤が容易に得られる懸濁重合法が特に好ましい。さらに一旦得られた重合粒子に更に単量体を吸着させた後、重合開始剤を用い重合させるシード重合方法も好適に利用することができる。このときは吸着させる単量体中に、極性を有する化合物を分散あるいは溶解させて使用することも可能である。
【００８２】
現像剤粒子の製造方法として懸濁重合法を利用する場合には、具体的には以下の製造方法によって直接的に現像剤粒子を製造することが可能である。結着樹脂となりうる重合性単量体中にワックス等の離型剤、着色剤、重合開始剤、架橋剤、その他の添加剤を加え、ホモジナイザー、超音波分散機等によって均一に溶解又は分散させた重合性単量体組成物を、分散安定剤を含有する水系媒体中に通常の攪拌機またはホモミキサー、ホモジナイザー等により分散させる。
【００８３】
好ましくは重合性単量体組成物の液滴が所望の現像剤粒子のサイズを有するように攪拌速度・時間を調整し、造粒する。その後は、分散安定剤の作用により、粒子状態が維持され、且つ粒子の沈降が防止される程度の攪拌を行えばよい。重合温度は４０℃以上、通常５０〜９０℃（好ましくは５５〜８５℃）の温度に設定して重合を行う。重合反応後半ばに昇温しても良く、必要に応じてｐＨ変更しても良い。更に、現像剤の定着時の臭いの原因となる未反応の重合性単量体、副生成物を除去するために反応後半、又は、反応終了後に一部水系媒体を留去してもよい。反応終了後、生成した現像剤粒子を洗浄・ろ過により収集し、乾燥する。
【００８４】
以下に重合法現像剤の材料に関して記載する。
【００８５】
本発明に用いる現像剤を重合方法で製造する際に用いられる重合性単量体としては、ラジカル重合が可能なビニル系重合性単量体が挙げられる。該ビニル系重合性単量体としては、単官能性重合性単量体或いは多官能性重合性単量体を使用することができる。
【００８６】
単官能性重合性単量体としては、スチレン；α−メチルスチレン、β−メチルスチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、２、４−ジメチルスチレン、ｐ−ｎ−ブチルスチレン、ｐ−ｔ−ブチルスチレン、ｐ−ｎ−ヘキシルスチレン、ｐ−ｎ−オクチルスチレン、ｐ−ｎ−ノニルスチレン、ｐ−ｎ−デシルスチレン、ｐ−ｎ−ドデシルスチレン、ｐ−メトキシスチレン、ｐ−フェニルスチレン等のスチレン誘導体；メチルアクリレート、エチルアクリレート、ｎ−プロピルアクリレート、ｉｓｏ−プロピルアクリレート、ｎ−ブチルアクリレート、ｉｓｏ−ブチルアクリレート、ｔ−ブチルアクリレート、ｎ−アミルアクリレート、ｎ−ヘキシルアクリレート、２−エチルヘキシルアクリレート、ｎ−オクチルアクリレート、ｎ−ノニルアクリレート、シクロヘキシルアクリレート、ベンジルアクリレート、ジメチルフォスフェートエチルアクリレート、ジエチルフォスフェートエチルアクリレート、ジブチルフォスフェートエチルアクリレート、２−ベンゾイルオキシエチルアクリレート等のアクリル系重合性単量体；メチルメタクリレート、エチルメタクリレート、ｎ−プロピルメタクリレート、ｉｓｏ−プロピルメタクリレート、ｎ−ブチルメタクリレート、ｉｓｏ−ブチルメタクリレート、ｔ−ブチルメタクリレート、ｎ−アミルメタクリレート、ｎ−ヘキシルメタクリレート、２−エチルヘキシルメタクリレート、ｎ−オクチルメタクリレート、ｎ−ノニルメタクリレート、ジエチルフォスフェートエチルメタクリレート、ジブチルフォスフェートエチルメタクリレート等のメタクリル系重合性単量体；メチレン脂肪族モノカルボン酸エステル；酢酸ビニル、プロピオン酸ビニル、安息香酸ビニル、ギ酸ビニル等のビニルエステル；ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテル等のビニルエーテル、ビニルメチルケトン、ビニルヘキシルケトン、ビニルイソプロピルケトン等のビニルケトンが挙げられる。
【００８７】
多官能性重合性単量体としては、ジエチレングリコールジアクリレート、トリエチレングリコールジアクリレート、テトラエチレングリコールジアクリレート、ポリエチレングリコールジアクリレート、１、６−ヘキサンジオールジアクリレート、ネオペンチルグリコールジアクリレート、トリプロピレングリコールジアクリレート、ポリプロピレングリコールジアクリレート、２、２’−ビス（４−（アクリロキシ・ジエトキシ）フェニル）プロパン、トリメチロールプロパントリアクリレート、テトラメチロールメタンテトラアクリレート、エチレングリコールジメタクリレートジエチレングリコールジメタクリレート、トリエチレングリコールジメタクリレート、テトラエチレングリコールジメタクリレート、ポリエチレングリコールジメタクリレート、１、３−ブチレングリコールジメタクリレート、１、６−ヘキサンジオールジメタクリレート、ネオペンチルグリコールジメタクリレート、ポリプロピレングリコールジメタクリレート、２、２’−ビス（４−（メタクリロキシ・ジエトキシ）フェニル）プロパン、２、２’−ビス（４−（メタクリロキシ・ポリエトキシ）フェニル）プロパン、トリメチロールプロパントリメタクリレート、テトラメチロールメタンテトラメタクリレート、ジビニルベンゼン、ジビニルナフタリン、ジビニルエーテル等が挙げられる。
【００８８】
上記した単官能性重合性単量体を単独或いは２種以上組み合わせて、又は、上記した単官能性重合性単量体と多官能性重合性単量体を組み合わせて使用することができる。多官能性重合性単量体は架橋剤として使用することも可能である。
【００８９】
また本発明に用いられる重合開始剤としては、油溶性開始剤及び／又は水溶性開始剤が用いられる。例えば、油溶性開始剤としては、２、２’−アゾビスイソブチロニトリル、２、２’−アゾビス−２、４−ジメチルバレロニトリル、１、１’−アゾビス（シクロヘキサン−１−カルボニトリル）、２、２’−アゾビス−４−メトキシ−２、４−ジメチルバレロニトリル等のアゾ化合物；アセチルシクロヘキシルスルホニルパーオキサイド、ジイソプロピルパーオキシカーボネート、デカノニルパーオキサイド、ラウロイルパーオキサイド、ステアロイルパーオキサイド、プロピオニルパーオキサイド、アセチルパーオキサイド、ｔ−ブチルパーオキシイソブチレート、シクロヘキサノンパーオキサイド、メチルエチルケトンパーオキサイド、ジクミルパーオキサイド、ｔ−ブチルヒドロパーオキサイド、ジ−ｔ−ブチルパーオイキサイド、クメンヒドロパーオキサイド等のパーオキサイド系開始剤が挙げられる。水溶性開始剤としては、過硫酸アンモニウム、過硫酸カリウム、２、２’−アゾビス（Ｎ，Ｎ’−ジメチレンイソブチロアミジン）塩酸塩、２、２’−アゾビス（２−アミノジノプロパン）塩酸塩、アゾビス（イソブチルアミジン）塩酸塩、２、２’−アゾビスイソブチロニトリルスルホン酸ナトリウム、硫酸第一鉄又は過酸化水素が挙げられる。更に重合性単量体の重合度を制御するために、連鎖移動剤、重合禁止剤等を添加し用いることが可能である。
【００９０】
架橋剤としては、上記多官能性重合性単量体の他に、２個以上の重合可能な二重結合を有する化合物が用いられる。例えば、ジビニルベンゼン、ジビニルナフタレンのような芳香族ジビニル化合物；エチレングリコールジアクリレート、エチレングリコールジメタクリレート、１、３−ブタンジオールジメタクリレートのような二重結合を２個有するカルボン酸エステル；ジビニルアニリン、ジビニルエーテル、ジビニルスルフィド、ジビニルスルホン等のジビニル化合物；及び３個以上のビニル基を有する化合物が挙げられる。これらは単独もしくは混合物として用いられる。
【００９１】
本発明に用いられる分散安定剤としては、無機系化合物と有機系化合物が使用可能であるが、無機系化合物としては、リン酸三カルシウム、リン酸マグネシウム、リン酸アルミニウム、リン酸亜鉛、炭酸カルシウム、炭酸マグネシウム、水酸化カルシウム、水酸化マグネシウム、水酸化アルミニウム、メタケイ酸カルシウム、硫酸カルシウム、硫酸バルイム、ベントナイト、シリカ、アルミナ、ヒドロキシアパタイト等が挙げられる。通常重合性単量体１００質量部に対して、水３００〜３０００質量部を分散媒体として使用するのが好ましい。有機系化合物としては、例えばポリビニルアルコール、ゼラチン、メチルセルロース、メチルヒドロキシプロピルセルロース、エチルセルロース、カルボキシメチルセルロースのナトリウム塩、デンプン等が使用される。これらの分散安定剤は、重合性単量体１００質量部に対して０．２〜２．０質量部を使用することが好ましい。
【００９２】
本発明においてより好ましく用いられる分散安定剤としては、硫酸、炭酸、リン酸、ピロリン酸、ポリリン酸の難水溶性金属塩があり、これらは分散媒中で高速攪拌下において酸アルカリ金属塩とハロゲン化金属塩との反応によって調製されることが好ましい。これらの分散剤の微細化のため、重合性単量体１００質量部に対して０．００１〜０．１質量部の界面活性剤を併用してもよい。具体的には市販のノニオン、アニオン、カチオン型の界面活性剤が利用できる。例えばドデシル硫酸ナトリウム、テトラデシル硫酸ナトリウム、ペンタデシル硫酸ナトリウム、オクチル硫酸ナトリウム、オレイン酸ナトリウム、ラウリル酸ナトリウム、ステアリン酸カリウム、オレイン酸カルシウム等が好ましく用いられる。
【００９３】
現像剤を重合して製造する際、重合性単量体中に加える離型剤としては、重量平均分子量（Ｍｗ）が３５０〜４０００、数平均分子量（Ｍｎ）が２００〜４０００であることが好ましく、より好ましくはＭｗが４００〜３５００、Ｍｎが２５０〜３５００であるものがよい。Ｍｗが３５０未満であり、Ｍｎが２００未満の場合には、現像剤の耐ブロッキング性が低下する傾向がある。Ｍｗが４０００を超え、Ｍｎが４０００を超える場合には、離型剤自体の結晶性が発現し、定着画像の透明性が低下する傾向がある。
【００９４】
本発明において、離型剤の分子量分布はＧＰＣにより次の条件で測定される。
装置：ＧＰＣ−１５０Ｃ（ウォーターズ社）
カラム：ＧＭＨ−ＭＴ３０ｃｍ２連（東ソー社製）
温度：１３５℃
溶媒：ｏ−ジクロロベンゼン（０．１％アイオノール添加）
流速：１．０ｍｌ／ｍｉｎ
試料：０．１５％の試料を０．４ｍｌ注入
以上の条件で測定し、試料の分子量算出にあたっては単分散ポリスチレン標準試料により作成した分子量較正曲線を使用する。さらにＭａｒｋ−Ｈｏｕｗｉｎｋ粘度式から導き出される換算式でポリエチレン換算することによって算出される。
【００９５】
離型剤は、融点（温度２０〜２００℃の範囲におけるＤＳＣ吸熱曲線の最大吸熱ピークに対応する温度）が３０〜１２０℃、より好ましくは５０〜９０℃であるものがよい。離型剤としては、室温で固体状態のワックスが好ましく、特に融点４０〜１００℃の固体ワックスが現像剤の耐ブロッキング性、多数枚耐久性、低温定着性、耐オフセット性の点で良い。ワックスとしては、パラフィンワックス、ケトンワックス、ポリオレフィンワックス、マイクロクリスタリンワックス、フィッシャートロプシュワックス等のポリメチレンワックス、アミドワックス、高級脂肪酸、長鎖アルコール、エステルワックス及びこれらのグラフト化合物、ブロック化合物等の誘導体が挙げられ、これらの低分子量成分が除去されたＤＳＣ吸熱曲線の最大吸熱ピークがシャープなものが好ましい。
【００９６】
好ましく用いられるワックスとしては、炭素数１０〜１００個の直鎖状のアルキルアルコール、直鎖状脂肪酸、直鎖状酸アミド、直鎖状エステルあるいは、モンタン系誘導体が挙げられる。これらワックスから液状脂肪酸の様な不純物を予め除去してあるものも好ましい。さらに好ましく用いられるワックスは、アルキレンを高圧下でラジカル重合あるいは低圧下でチーグラー触媒又は、その他の触媒を用いて重合した低分子量のアルキレンポリマー；アルキレンを重合する際に副生する低分子量アルキレンポリマーを分離精製したもの；一酸化炭素及び水素からなる合成ガスからアーゲ法により得られる炭化水素ポリマーの蒸留残分から、あるいは、蒸留残分を水素添加して得られる合成炭化水素から、特定の成分を抽出分別したポリメチレンワックスが挙げられる。これらワックスには酸化防止剤が添加されていても良い。本発明に用いられるエステル系ワックスは、下記一般式（１１）〜（１５）で示される化合物から形成され、融点４０〜１００℃を有するものが用いられる。
【００９７】
【化１１】

（式中、ａ及びｂは０〜４の整数であり、ａ＋ｂは４である。Ｒ⁵及びＲ⁶は炭素数が１〜４０の有機基であり、Ｒ⁵とＲ⁶との炭素数差が３以上である。ｍ及びｎは０〜２５の整数であり、ｍとｎは同時に０になることはない。）
【００９８】
【化１２】

（式中、ｃ及びｄは０〜３の整数であり、ｃ＋ｄは１〜３である。Ｒ⁸及びＲ⁹は炭素数が１〜４０の有機基であり、Ｒ⁸とＲ⁹との炭素数差が３以上である。Ｒ⁷は水素原子、炭素数が１以上の有機基である。但し、ｃ＋ｄ＝２のとき、Ｒ⁷のどちらか一方は、炭素数が１以上の有機基である。ｋは１〜３の整数である。ｍ及びｎは０〜２５の整数であり、ｍとｎは同時に０になることはない。）
【００９９】
【化１３】

（式中、Ｒ¹⁰及びＲ¹²は炭素数６〜３２を有する有機基であり、Ｒ¹⁰とＲ¹²は同じものであってもなくてもよい。Ｒ¹¹は炭素数１〜２０を有する有機基を示す。）
【０１００】
【化１４】

（式中、Ｒ¹³及びＲ¹⁴は炭素数６〜３２を有する有機基であり、Ｒ¹³とＲ¹⁵は同じものであってもなくてもよい。
Ｒ¹⁴は−ＣＨ₂ＣＨ₂ＯＣ₆Ｈ₄ＯＣＨ₂ＣＨ₂−、

又は−(ＣＨ₂)_f−である。ｅは１〜１０の整数、ｆは１〜２０の整数を示す。）
【０１０１】
【化１５】

（式中、ｇは０〜４の整数であり、ｈは１〜４の整数であり、ｇ＋ｈは４である。Ｒ¹⁶は炭素数が１〜４０の有機基である。ｍ及びｎは０〜２５の整数であり、ｍとｎが同時に０になることはない。）
エステル化合物からなる離型剤としてのエステルワックスとしては以下の離型剤Ｎｏ．１〜Ｎｏ．１２のものが例示される。
【０１０２】
【化１６】

該離型剤が、上記構造式を有するエステル化合物を有するエステルワックスの場合、良好な透明性を発現するとともに、現像剤粒子中に含有させた場合には良好な定着性を示すものである。
【０１０３】
重合性単量体組成物を使用して、水系媒体中で直接的に現像剤粒子を生成する場合には、離型剤は重合性単量体１００質量部に対して１〜４０質量部、より好ましくは３〜３０質量部を配合し、現像剤粒子に含有されるのがよい。
【０１０４】
溶融混練粉砕法による乾式現像剤製法に比べ重合法による現像剤製法においては、現像剤粒子内部の極性樹脂に、より多量の離型剤を内包化させ易いので、乾式現像剤製法と比較し、一般に多量の離型剤を用いることが可能となり、定着時のオフセット防止効果に有効である。該離型剤の添加量が下限より少ないとオフセット防止効果が低下しやすく、上限を超える場合では耐ブロッキング効果が低下し、耐オフセット効果にも悪影響を与えやすく、現像剤のドラム融着、現像剤の現像スリーブ融着を起こしやすく、重合法により現像剤粒子を生成する場合には粒度分布の広い現像剤粒子が生成する傾向にある。
【０１０５】
着色剤としては、公知のものが使用でき、例えば、カーボンブラック、鉄黒の他、Ｃ．Ｉ．ダイレクトレッド１、Ｃ．Ｉ．ダイレクトレッド４、Ｃ．Ｉ．アシッドレッド１、Ｃ．Ｉ．ベーシックレッド１、Ｃ．Ｉ．モーダントレッド３０、Ｃ．Ｉ．ダイレクトブルー１、Ｃ．Ｉ．ダイレクトブルー２、Ｃ．Ｉ．アシッドブルー９、Ｃ．Ｉ．アシッドブルー１５、Ｃ．Ｉ．ベーシックブルー３、Ｃ．Ｉ．ベーシックブルー５、Ｃ．Ｉ．モーダントブルー７、Ｃ．Ｉ．ダイレクトグリーン６、Ｃ．Ｉ．ベーシックグリーン４、Ｃ．Ｉ．ベーシックグリーン６等の染料、黄鉛、カドミウムイエロー、ミネラルファストイエロー、ネーブルイエロー、ナフトールイエローＳ、ハンザイエローＧ、パーマネントイエローＮＣＧ、タートラジンレーキ、モリブデンオレンジ、パーマネントオレンジＧＴＲ、ベンジジンオレンジＧ、カドミウムレツド、パーマネントレッド４Ｒ、ウォッチングレッドカルシウム塩、ブリリアントカーミン３Ｂ、ファストバイオレットＢ、メチルバイオレットレーキ、紺青、コバルトブルー、アルカリブルーレーキ、ビクトリアブルーレーキ、キナクリドン、ローダミンレーキ、フタロシアニンブルー、ファーストスカイブルー、ピグメントグリーンＢ、マラカイトグリーンレーキ、ファイナルイエローグリーンＧ等の顔料がある。
【０１０６】
重合法を用いて現像剤を得る場合は、着色剤の持つ重合阻害性や水相移行性に注意を払う必要があり、好ましくは、表面改質をしておくことが良い。例えば、重合阻害のない物質による疎水化処理を施しておいたほうが良い。特に、染料系やカーボンブラックは、重合阻害性を有しているものが多いので使用の際に注意を要する。染料系を表面処理する好ましい方法としては、あらかじめこれら染料の存在下に重合性単量体を重合させる方法が挙げられ、得られた着色重合体を重合性単量体組成物に添加する。
【０１０７】
また、カーボンブラックについては、上記染料と同様の処理の他、カーボンブラックの表面官能基と反応する物質、例えば、ポリオルガノシロキサン等でグラフト処理を行っても良い。該着色剤の添加量は、結着樹脂１００質量部に対し１〜２０質量部添加して用いられる。黒色着色剤として磁性体を用いた場合には、他の着色剤と異なり、結着樹脂１００質量部に対し３０〜２００質量部添加して用いられる。
【０１０８】
現像剤における各種の特性付与を目的とする上記以外の添加剤としては、耐久性の点から、現像剤粒子の体積平均粒径の１／５以下の粒径であることが好ましい。この添加剤の粒径とは、電子顕微鏡における現像剤粒子の表面観察により求めたその平均粒径を意味する。これらの特性付与を目的とした添加剤としては、例えば、流動性付与剤、研磨剤、滑剤などが用いられる。
【０１０９】
現像剤の体積平均粒径は、下記方法により測定できる。
【０１１０】
測定装置として、コールカウンターＴＡ−II型あるいはコールターマルチサイザーII（コールター社製）を用いる。電解液は１級塩化ナトリウムを用いて１％ＮａＣｌ水溶液を調製する。例えば、ＩＳＯＴＯＮＲ−II（コールターサイエンティフィックジャパン社製）が使用できる。
【０１１１】
測定方法としては、前記電界水溶液１００〜１５０ｍｌ中に分散剤として界面活性剤（好ましくはアルキルベンゼンスルフォン酸塩）を０．１〜５ｍｌ加え、さらに測定試料を２〜２０ｍｇ加える。試料を懸濁下電解液は超音波分散機で約１〜３分間分散処理を行い、前記測定装置により、アパーチャーとして１００μｍアパーチャーを用い、現像剤の体積及び個数を測定して体積分布と個数分布とを算出する。測定された体積分布から体積平均粒径を算出する。測定に際しては、各チャンネルの中央値をチャンネル毎の代表値とする。
【０１１２】
流動性付与剤としては、カーボンブラック、フッ化カーボンなどが挙げられる。それぞれ疎水化処理を行ったものがより好ましい。研磨剤としては、窒化物（窒化ケイ素など）、炭化物（炭化ケイ素など）、金属塩（硫酸カルシウム、硫酸バリウム、炭酸カルシウムなど）が挙げられる。滑剤としては、フッ素系樹脂粉末（フッ化ビニリデン、ポリテトラフルオロエチレンなど）、脂肪酸金属塩（ステアリン酸亜鉛、ステアリン酸カルシウムなど）などが挙げられる。
【０１１３】
これらの添加剤は、現像剤粒子１００質量部に対し０．１〜１０質量部が用いられ、好ましくは０．１〜５質量部が用いられる。これらの添加剤は、単独で用いても、また、複数併用してもよい。
【０１１４】
また、現像剤を磁性を有する現像剤として用いる場合には、現像剤の中に磁性体を含有させるが、このような磁性体としては、磁場の中におかれて磁化される物質が用いられる。
【０１１５】
磁性体としては、鉄、コバルト、ニッケル、銅、マグネシウム、マンガン、アルミニウム、硅素などの元素を含む金属酸化物などがある。中でも四三酸化鉄、γ−酸化鉄など、酸化鉄を主成分とするものが好ましい。また、現像剤帯電性コントロールの観点から硅素元素またはアルミニウム元素など、他の金属元素を含有していてもよい。これら磁性体は、窒素吸着法によるＢＥＴ比表面積が好ましく２〜３ｍ²／ｇ、特に３〜２８ｍ²／ｇ、更にモース硬度が５〜７の磁性体が好ましい。
【０１１６】
磁性体の形状としては、８面体、６面体、球状、針状、鱗片状などがあるが、８面体、６面体、球体、不定形型の異方性の少ないものが画像濃度を高める上で好ましい。磁性体の個数平均粒径としては０．０５〜１．０μｍが好ましく、さらに好ましくは０．１〜０．６μｍ、さらには０．１〜０．４μｍが好ましい。
【０１１７】
磁性体量は結着樹脂１００質量部に対し３０〜２００質量部、好ましくは４０〜２００質量部、更には５０〜１５０質量部が好ましい。３０質量部未満では現像剤搬送に磁気力を用いる現像装置においては、搬送性が不十分で現像剤担持体上の現像剤層にむらが生じ画像むらとなる傾向であり、さらに現像剤トリボの上昇に起因する画像濃度の低下が生じやすい傾向がある。一方、２００質量部を越えると定着性に問題が生ずる傾向がある。
【０１１８】
また、本発明においては、現像剤の帯電性を制御する目的で材料中に荷電制御剤を添加しておくことが好ましい。これら荷電制御剤としては、公知のもののうち、重合阻害性、水相移行性の殆ど無いものが用いられるのが好ましく、例えば、正荷電制御剤としてニグロシン系染料、トリフェニルメタン系染料、四級アンモニウム塩、アミン系及びポリアミン系化合物が挙げられ、負荷電制御剤としては、含金属サリチル酸系化合物、含金属モノアゾ系染料化合物、スチレン−アクリル酸共重合体、スチレン−メタクリル酸共重合体等が挙げられる。
＜３＞本発明の現像方法、現像装置および画像形成装置
本発明の現像方法は上記したような現像剤担持体を用いる方法であり、本発明の現像装置および画像形成装置は、上記したような現像剤担持体が組み込まれた装置である。図を用いて詳細に説明するが、本発明はこれらに限定されない。
【０１１９】
図１は、磁性一成分現像剤を用いた際の本発明の現像装置の一実施形態の模式図を示す。図１において、公知のプロセスにより形成された静電潜像を保持する像担持体である電子写真感光ドラム１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８は、現像剤容器としてのホッパー３によって供給された磁性を有する一成分現像剤４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８と感光ドラム１とが対向している現像領域Ｄに現像剤４を搬送する。現像スリーブ８内には、現像剤４を現像スリーブ８上に磁気的に吸引且つ保持する為に、磁石が内接されているマグネットローラ５が配置されている。
【０１２０】
本発明の現像装置で用いられる現像スリーブ８は、基体としての金属円筒管６上に被覆された導電性樹脂被覆層７を有する。ホッパー３中には、現像剤４を攪拌するための攪拌翼１０が設けられている。１１は現像スリーブ８とマグネットローラー５とが非接触状態にあることを示す間隙である。
【０１２１】
現像剤４は、現像剤相互間及び現像スリーブ８上の導電性樹脂被覆層７との摩擦により、感光ドラム１上の静電潜像を現像することが可能な摩擦帯電電荷を得る。図１の例では、現像領域Ｄに搬送される現像剤４の層厚を規制するために、現像剤層厚規制部材としての強磁性金属製の磁性規制部材２が、現像スリーブ８の表面から約５０〜５００μｍのギャップ幅を有する様に、ホッパー３から垂下されている。マグネットローラ５の磁極Ｎ１からの磁力線が磁性規制部材２に集中することにより、現像スリーブ８上に現像剤４の薄層が形成される。本発明においては、この磁性規制部材２にかえて非磁性部材を使用することもできる。
現像剤層厚規制部材により、現像スリーブ８上に形成される現像剤４の薄層の厚みは、現像領域Ｄにおける現像スリーブ８と感光ドラム１との間の最小間隙よりも更に薄いものとなるようにする。
【０１２２】
本発明の現像剤担持体は、上記の様に現像剤の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組み込むのが特に有効であるが、現像領域Ｄにおいて、現像剤層の厚みが現像スリーブ８と感光ドラム１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の現像剤担持体を適用することができる。
【０１２３】
説明の煩雑を避けるため、非接触型現像装置を例にして以下説明する。
【０１２４】
上記現像スリーブ８に担持された磁性を有する一成分現像剤４を飛翔させる為、上記現像スリーブ８にはバイアス手段としての現像バイアス電源９により現像バイアス電圧が印加される。この現像バイアス電圧として直流電圧を使用するときに、静電潜像の画像部（現像剤４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８に印加するのが好ましい。
【０１２５】
現像された画像の濃度を高め、或は階調性を向上するためには、現像スリーブ８に交番バイアス電圧を印加し、現像領域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、上記した現像画像部の電位と背景部の電位の中間の値を有する直流電圧成分を重畳した交番バイアス電圧を現像スリーブ８に印加するのが好ましい。
【０１２６】
高電位部と低電位部を有する静電潜像の高電位部に現像剤を付着させて可視化する、所謂、正規現像の場合には、静電潜像の極性と逆極性に帯電する現像剤を使用する。
【０１２７】
高電位部と低電位部を有する静電潜像の低電位部に現像剤を付着させて可視化する、所謂、反転現像の場合には、静電潜像の極性と同極性に帯電する現像剤を使用する。
【０１２８】
高電位、低電位というのは、絶対値による表現である。これらいずれの場合にも、現像剤４は少なくとも現像スリーブ８との摩擦により帯電する。
【０１２９】
図２は、本発明の現像装置の他の実施形態を示す構成模式図であり、図３は、本発明の現像装置の更に他の実施形態を示す構成模式図である。
【０１３０】
図２及び図３に示した現像装置では、現像スリーブ８上の現像剤４の層厚を規制する現像剤層厚規制部材１２および１２’として、ウレタンゴム、シリコーンゴムの如きゴム弾性を有する材料、或いはリン青銅、ステンレス鋼の如き金属弾性を有する材料の弾性板からなる現像剤層厚規制部材を使用する。図２の現像装置では、この現像剤層厚規制部材１２を現像スリーブ８の回転方向と逆方向の向きで圧接させており、図３の現像装置では、この現像剤層厚規制１２’を現像スリーブ８の回転方向と順方向の向きで圧接させているのが特徴である。
【０１３１】
これらの現像装置では、現像スリーブ８に対して、現像剤層を介して現像剤層厚規制部材１２または１２’を弾性的に圧接することによって、現像スリーブ上に現像剤の薄層を形成することから、現像スリーブ８上に、上記した図１の引用例の場合よりも更に薄い現像剤層を形成することができる。現像スリーブ８に対する現像剤層厚規制部材１２および１２’の当接圧力は、線圧５〜５０ｇ／ｃｍであることが、現像剤の規制を安定化させ、現像剤層厚を好適にさせることが出来る点で好ましい。現像剤層厚規制部材の当接圧力が線圧５ｇ／ｃｍ未満の場合には、現像剤の規制が弱くなり、カブリや現像剤もれの原因となり、線圧５０ｇ／ｃｍを超える場合には、現像剤へのダメージが大きくなり、現像剤劣化やスリーブ及びブレードへの融着の原因となり易い。
【０１３２】
図２及び図３の現像装置の他の基本的構成は図１に示した現像装置と同じである。図１〜３はあくまでも本発明の現像装置を模式的に例示したものであり、現像剤容器（ホッパー３）の形状、攪拌翼１０の有無、磁極の配置に様々な形態があることは言うまでもない。
【０１３３】
また図４に非磁性現像剤を用いた際の本発明の一実施形態の現像装置の模式図を示す。図４の現像装置は図１の現像装置と異なり、非磁性現像剤１３を用いるために現像スリーブとして、金属棒１４の表面に導電性樹脂被覆層７が設けられたものが用いられており、従って磁石は内設されていない。ホッパー３内の非磁性現像剤１３は、現像剤層厚規制部材１２によって現像剤層厚が規制され、更に現像剤層厚規制部材１２或いは現像スリーブの導電性被覆層７との摩擦により摩擦帯電された状態で現像スリーブ表面に担持され、該現像スリーブによって現像領域へと搬送される。
【０１３４】
図５においては、現像剤層厚規制部材１２として先に説明した図２に示したタイプのものが用いられている。また現像スリーブには、中空の金属円筒管１５の表面に導電性樹脂被覆層７が設けられたものが用いられているが、図５に示した現像装置では現像スリーブ内に磁石が内設されていない。また、ホッパー３内には現像領域で感光ドラム上に現像移行されなかった現像剤を、現像スリーブ上から剥ぎ取り、新たに現像剤を供給するための現像剤供給剥ぎ取り部材１６が設置されている。
【０１３５】
供給剥ぎ取り部材１６としては、例えば樹脂、ゴム、スポンジなどのローラ部材や、ベルト部材、ブラシ部材等が用いられる。このような供給剥ぎ取り部材１６を設けることによって、感光ドラム１上に現像移行されなかった現像剤を、一旦現像スリーブ表面から剥ぎ取ることで、現像スリーブ上に発生する恐れのある不動現像剤を防いだり、現像剤の帯電を均一化させる働きをする。
【０１３６】
供給剥ぎ取り部材１６に弾性ローラを用いる場合、供給剥ぎ取りローラの周速は、現像スリーブの移動に対してカウンター方向（矢印Ｘ方向）に回転する場合、現像スリーブ８の周速１００％に対して、好ましくは２０〜１２０％、より好ましくは３０〜１００％であることがよい。供給剥ぎ取りローラ１６の周速が２０％未満の場合には、現像剤の供給が不足し、ベタ画像の追従性が低下し、ゴースト画像の原因となり、１２０％を超える場合には現像剤の供給量が多くなり、現像剤層厚の規制不良や帯電量不足によるカブリの原因となり、さらに現像剤にダメージを与えやすいため、現像剤劣化によるカブリや現像剤融着の原因となり易い。供給剥ぎ取りローラの回転方向が現像スリーブの表面と同（順）方向の場合には、周速はスリーブ周速に対して、好ましくは１００〜３００％、より好ましくは１０１〜２００％であることが上記の現像剤供給量の点で良い。供給剥ぎ取りローラの回転方向は、現像スリーブの表面とカウンター方向に回転することが、剥ぎ取り性及び供給性の点でより好ましい。
【０１３７】
現像スリーブ８に対する供給剥ぎ取り部材１６の侵入量は、０．５〜２．５ｍｍであることが、現像剤の供給及び剥ぎ取りの点で好ましい。供給剥ぎ取り部材の侵入量が０．５ｍｍ未満の場合には、剥ぎ取り不足により、ゴーストが発生し易くなり、侵入量が２．５ｍｍを超える場合には、現像剤のダメージが大きくなり、現像剤劣化により融着やカブリの原因となり易い。
【０１３８】
上記のようにして現像スリーブ上にトナー層を形成する図１〜図５に示したような現像装置は、磁性現像剤においても非磁性現像剤においても使用することができる。
【０１３９】
次に図６を参照しながら、図３で例示した本発明の現像装置を使用した画像形成装置の一例について説明する。
【０１４０】
先ず、一次帯電手段としての接触（ローラ）帯電手段１７により、像担持体としての感光ドラム１の表面を負極性に帯電し、レーザ光の露光１８によるイメージスキャニングによりデジタル潜像が感光ドラム１上に形成される。次に、現像剤層厚規制部材１２’を有し、現像剤担持体としての現像スリーブ８が具備されている現像装置によって、上記のデジタル潜像が、現像容器としてのホッパー３内の負帯電性一成分現像剤４によって反転現像される。図６に示す様に、現像領域Ｄにおいて感光ドラム１の導電性基体は接地されている。現像スリーブ８にはバイアス印加手段９により交番バイアス電圧、振動電界及び／又は直流電圧が印加されている。
【０１４１】
次に、被記録材Ｐが搬送されて転写部に来ると、転写手段としての接触（ローラ）転写手段１９により被記録材Ｐの背面（感光ドラム側と反対面）から電圧印加手段２０で帯電されることにより、感光ドラム１の表面上に形成されている現像画像が接触転写手段１９で被記録材Ｐ上へ転写される。次に、感光ドラム１から分離された被記録材Ｐは、定着手段としての加熱加圧ローラ定着装置２１に搬送され、該定着装置によって被記録材Ｐ上の現像画像の定着処理がなされる。
【０１４２】
転写工程後の感光ドラム１に残留する一成分現像剤４は、クリーニングブレード２２を有するクリーニング手段２３で除去される。残留する一成分現像剤４が少ない場合には、クリーニング工程を省くことも可能である。クリーニング後の感光ドラム１は、必要によりイレース露光２４により除電され、再度、一次帯電手段としての接触（ローラ）帯電手段１７による帯電工程から始まる上記工程が繰り返される。
【０１４３】
感光ドラム（即ち、像担持体）１は、感光層及び導電性基体を有するものであり、矢印Ｂ方向に動く。現像スリーブ８は、現像領域Ｄにおいて感光ドラム１の表面と同方向（矢印Ａ方向）に進む様に回転する。ホッパー３内の一成分現像剤４は、現像スリーブ８上に担持され、且つ現像スリーブ８の表面との摩擦及び／又現像剤同士の摩擦によって、例えば、マイナスのトリボ電荷が与えられる。更に、現像剤規制規制部材１２’により、現像剤層の厚さを薄く（３０μｍ〜３００μｍ）且つ均一に規制して、現像領域Ｄにおける感光ドラム１と現像スリーブ８との間隙よりも薄い現像剤層を形成させる。現像スリーブ８の回転速度を調整することによって、現像スリーブ８の表面速度が感光ドラム１の表面の速度と実質的に等速、もしくはそれに近い速度となる様にする。
【０１４４】
現像領域Ｄにおいて、現像スリーブ８に現像バイアス電圧として、交番バイアス電圧または振動電界をバイアス印加手段９により印加してもよい。この交番バイアス電圧はｆが２００〜４，０００Ｈｚ、Ｖｐｐが５００〜３，０００Ｖであればよい。現像領域Ｄにおける現像剤の転移に際し、感光ドラム１の表面の静電気力、及び交番バイアス電圧又は振動電界の如き現像バイアス電圧の作用によって、現像剤は静電潜像側に転移する。
【０１４５】
一次帯電手段としては、上記に接触帯電手段として帯電ローラ１７を用いて説明したが、帯電ブレード、帯電ブラシの様な接触帯電手段でもよく、更に非接触のコロナ帯電手段でもよい。しかしながら、帯電によるオゾンの発生が少ない点で接触帯電手段の方が好ましい。
【０１４６】
転写手段としては、上記に転写ローラ１９の如き接触転写手段を用いて説明したが、非接触のコロナ転写手段でもよい。しかしながら、こちらも転写によるオゾンの発生が少ない点で接触転写手段の方が好ましい。
【０１４７】
【実施例】
以下に、実施例により本発明をより具体的に説明する。本発明はこれら実施例に限定されるものではない。なお、以下の配合における部数は全て質量部である。
【０１４８】
【実施例１】
＜磁性現像剤１の製造＞
反応容器のイオン交換水５００質量部に０．１Ｍ−Ｎａ₃ＰＯ₄水溶液３２０質量部を投入し、６０℃に加温した後、１Ｍ−ＣａＣｌ₂水溶液を４７質量部を徐々に添加してＣａ₃（ＰＯ₄）₂を含む水系媒体を得た。
【０１４９】
下記材料をアトライターを用いて均一に分散混合した。
・スチレン ８０質量部
・n-ブチルアクリレート ２０質量部
・不飽和ポリエステル樹脂 ２質量部
・飽和ポリエステル樹脂 ３質量部
・モノアゾ染料系のＦｅ化合物 １質量部
・疎水化処理磁性体 ９０質量部
この単量体組成物を６０℃に加温し、そこにエステルワックス（ＤＳＣにおける吸熱ピークの極大値７２℃）６質量部を添加混合溶解し、これに重合開始剤２，２’−アゾビス（２，４−ジメチルバレロニトリル）５質量部を溶解した。前記水系媒体中に上記重合性単量体組成物を投入し、６０℃、Ｎ₂パージ下において、ＴＫ式ホモミキサー（特殊機化工業製）にて１００００ｒｐｍで１５分間攪拌し、造粒した。その後、パドル攪拌翼にて攪拌しつつ６０℃で６時間反応させた。その後、液温を８０℃とし、更に４時間攪拌を続けた。反応終了後、８０℃で更に２時間蒸留を行い、その後、懸濁液を冷却し、塩酸を加えてＣａ₃（ＰＯ₄）₂を溶解し、濾過、水洗、乾燥を行い、現像剤粒子を得た。この現像剤粒子１００質量部にヘキサメチルジシラザンで処理した疎水性シリカ１．２質量部をヘンシェルミキサー（三井三池化工機（株））で混合し、磁性現像剤１を得た。現像剤の物性を表１に示す。
【０１５０】
【表１】

＜現像剤担持体１の製造＞
次に現像担持体の製造について述べる。
【０１５１】
まず、上記式（３）で表される第４級アンモニウム塩化合物の鉄粉との摩擦帯電量は、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求めたところ、正極性であった。
【０１５２】
また、導電性球状粒子として、導電性球状炭素粒子Ａを用いた。物性を表２に示す。個数平均粒径５．０μｍ、真密度１．５０ｇ／ｃｍ^３、体積抵抗値７．５×１０^−２Ω・ｃｍ、長径／短径の比が１．１５であった。
【０１５３】
【表２】

下記材料を直径２ｍｍのジルコニア粒子にて３時間サンドミルを用いて分散を行った。
・カーボン １０質量部
・グラファイト ９０質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％）５００質量部
・第４級アンモニウム塩化合物 ４０質量部
・上記球状炭素粒子Ａ ４０質量部
・メタノール １３０質量部
その後ジルコニア粒子を篩で分離し、メタノールで固形分を３２％に調整し塗料１を得た。この塗料をスプレー法にて直径２４．５ｍｍのアルミニウム円筒体上に約１２μｍの被膜を形成させ、次いで熱風乾燥器により１５０℃／３０分間加熱・硬化させ、樹脂被膜層を有する現像剤担持体１を作製した。表３に塗料処方及び現像剤担持体の物性を示す。
【０１５４】
【表３】

この現像剤担持体をＮＰ６３５０（キヤノン製複写機）に組込み、上記現像剤を用いて、画出しを行い評価した。結果を表４及び表５に示す。
＜画出し評価方法＞
下記に挙げる評価項目について耐久試験を行い、評価した。
（１）画像濃度
画出しは、２４℃、１０％ＲＨの常温低湿（Ｎ／Ｌ）、及び３０℃、８０％ＲＨの高温高湿（Ｈ／Ｈ）環境下にて、ＮＰ６３５０については１０万枚（１００ｋ）、クリエイティブプロセッサー６６０については１万７千枚（１７ｋ）まで行った。画像比率５．５％のテストチャート上の直径５ｍｍ黒丸の画像濃度を反射濃度ＲＤ９１８（マクベス社製）で測定して５点の平均値をとって画像濃度とした。
（２）現像剤帯電量（Ｑ／Ｍ）及び現像剤搬送量（Ｍ／Ｓ）
現像剤担持体上に担持された現像剤を金属円筒管と円筒フィルターにより吸引捕集し、その際金属円筒管を通じてコンデンサーに蓄えられた電荷量Ｑ、捕集された現像剤重量Ｍと、現像剤を吸引した面積Ｓから、単位重量当たりの電荷量Ｑ／Ｍ（ｍＣ／ｋｇ）と及び単位重量当たりの現像剤重量Ｍ／Ｓ（ｍｇ／ｃｍ²）を計算し、それぞれ現像剤帯電量（Ｑ／Ｍ）、現像剤搬送量（Ｍ／Ｓ）とした。
（３）スジ、ムラ
ベタ黒、ハーフトーン、ライン画像等の各種画像を確認し、その際、現像剤担持体上のスジ、波状ムラ等、現像剤担持体上での現像剤コート不良の目視による観察を参考にして、評価結果を下記の指標で示した。
◎：画像にも現像剤担持体上にも全く確認できない。
○：現像剤担持体上でわずかに確認できるが、画像ではほとんど確認できない。
○△：数枚〜数十枚に１枚程度画像を透かしてみると確認できる。
△○：ハーフトーン画像又はベタ黒画像の１枚目で、現像剤担持体周期の１周目に確認できる。
△：ハーフトーン画像又はベタ黒画像で確認できる。実用レベル下限。
△×：ベタ黒画像全体で画像不良が確認できる。実用不可レベル。
×：ベタ白画像上にも確認できる。
（４）ブロッチ
ベタ黒、ハーフトーン等の各種画像を確認し、その際、現像剤担持体上のブロッチ等の現像剤担持体上での現像剤コート不良の目視による観察を参考にして、評価結果を下記の指標で示した。
◎：画像にも現像剤担持体上にも全く確認できない。
○：現像剤担持体上でわずかに確認できるが、画像ではほとんど確認できない。
○△：数枚〜数十枚に１枚程度画像を透かしてみると確認できる。
△○：ハーフトーン画像又はベタ黒画像の１枚目で、現像剤担持体周期の１周目に確認できる。
△：ハーフトーン画像又はベタ黒画像で確認できる。実用レベル下限。
△×：ベタ黒画像全体で画像不良が確認できる。実用不可レベル。
×：ベタ白画像上にも確認できる。
（５）ゴースト
ベタ白部とベタ黒部が隣り合う画像を現像した現像剤担持体の位置が現像剤担持体の次の回転時に現像位置に来て、ハーフトーン画像を現像するようにして、ハーフトーン画像上に現れる濃淡差を目視で下記の基準で評価した。
○：濃淡差が全く見られない。
○△：軽微な濃淡差が見られる。
△：濃淡差がやや見られるが実用可。
×：濃淡差が顕著に見られ、実用不可。
（６）樹脂被覆層の耐汚染性
耐久後の現像剤担持体表面をＳＥＭで観察し、現像剤汚染の程度を下記の基準で評価した。
○：軽微な汚染が観察される。
○△：やや汚染が観察される。
△：部分的に汚染が観察される。
×：著しい汚染が観察される。
（７）導電性樹脂被覆層の削れ量（膜削れ）
ＫＥＹＥＮＣＥ社製レーザ寸法測定器を用いた。コントローラＬＳ−５５００およびセンサーヘッドＬＳ−５０４０Ｔを用い、現像剤担持体固定治具および現像剤担持体送り機構を取り付けた装置にセンサー部を別途固定し、現像剤担持体の外径寸法の平均値から測定を行った。測定は現像剤担持体長手方向に対し、３０分割して３０箇所、計６０箇所の測定を行い、その平均値をとった。表面に樹脂被覆層塗布前の現像剤担持体の外径を予め測定しておき、表面に樹脂被覆層形成後の外径、さらに耐久使用後の外径を測定し、その差分をコート膜厚および削れ量とした。
（８）転写率
評価法としては、耐久前後におけるドラム潜像上及び紙上のトナー量を測定し、その比から転写率を算出した。また耐久前後、転写率の比より転写性維持を算出した。評価の指標は以下の通りとした。
○：耐久前後で９０％以上の転写維持率を維持したもの
△：耐久前後で８０〜９０％に転写維持率が低下したもの
×：耐久前後で８０％以下に転写維持率が低下したもの
【０１５５】
【表４】

【０１５６】
【表５】

【０１５７】
【実施例２】
上記式（４）で表される第４級アンモニウム塩化合物を実施例１と同様に鉄粉を用いたブローオフ法により帯電量を測定したところ、正極性であった。上記式（４）で表される第４級アンモニウム塩化合物とした以外は、実施例１と同様にして塗料を作製し、現像剤担持体２を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１５８】
【実施例３】
上記式（５）で表される第４級アンモニウム塩化合物を実施例１と同様に鉄粉を用いたブローオフ法により帯電量を測定したところ、正極性であった。上記式（５）で表される第４級アンモニウム塩化合物とした以外は、実施例１と同様にして塗料を作製し、現像剤担持体３を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１５９】
【実施例４】
実施例１において、上記式（３）で表される第４級アンモニウム塩化合物の添加量を４０質量部から１０質量部に変えて塗料を作製した以外は、実施例１と同様にして現像剤担持体４を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１６０】
【実施例５】
実施例１において、上記式（３）で表される第４級アンモニウム塩化合物の添加量を４０質量部から６０質量部に変えて塗料を作製した以外は、実施例１と同様にして現像剤担持体５を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１６１】
【実施例６】
実施例５において、上記式（３）で表される第４級アンモニウム塩化合物を上記式（４）で表される第４級アンモニウム塩化合物に変えて塗料を作製した以外は、現像剤担持体６を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１６２】
【実施例７】
実施例４において、上記式（３）で表される第４級アンモニウム塩化合物を上記式（４）で表される第４級アンモニウム塩化合物に代えて塗料を作製した以外は、現像剤担持体７を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１６３】
【実施例８】
実施例１において用いた、個数平均粒径５．０μｍの球状炭素粒子Ａの代わりに、個数平均粒径５．１μｍのＰＭＭＡ（ポリメタクリル酸メチル）粒子Ｂを用いた以外は、実施例１と同様にして現像剤担持体８を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１６４】
このＰＭＭＡ粒子Ｂは、真密度１．１９ｇ／ｃｍ^３、体積抵抗値１０^１５Ω・ｃｍ以上、長径／短径の比が１．１２であった。
【０１６５】
【実施例９】
実施例１の現像剤担持体の製造において、樹脂被膜層に用いるグラファイトの代わりに窒化硼素を用いて、以下の処方により塗料を作製し、実施例１と同様にして現像剤担持体９を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
・カーボン １０質量部
・窒化硼素 ９０質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％）５００質量部
・第４級アンモニウム塩化合物 ４０質量部
・上記球状炭素粒子Ａ ４０質量部
・メタノール １５０質量部
【０１６６】
【実施例１０】
実施例１の現像剤担持体の製造において、樹脂被膜層に用いるグラファイトの代わりに二硫化モリブテンを用いて以下の処方により塗料を作製し、実施例１と同様にして現像剤担持体１０を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
・カーボン １０質量部
・二硫化モリブテン １００質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％）５００質量部
・第４級アンモニウム塩化合物（式３） ４０質量部
・上記球状炭素粒子Ａ ４０質量部
・メタノール １７０質量部
【０１６７】
【実施例１１】
実施例１の現像剤担持体の製造において、樹脂被膜層に用いる塗料を以下の処方により作製し、実施例１と同様にして現像剤担持体１１を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
・６６ナイロンを主成分とする ８３３質量部
ナイロン共重合物
・カーボン １０質量部
・グラファイト ９０質量部
・第４級アンモニウム塩化合物（式３） ４０質量部
・上記球状炭素粒子Ａ ４０質量部
・メタノール １３０質量部
【０１６８】
【実施例１２】
実施例１の現像剤担持体の製造において、樹脂被膜層に用いる塗料を以下の処方により作製し、実施例１と同様にして現像剤担持体１２を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
・ウレタン樹脂（固形分４０％） ６２５質量部
・カーボン １０質量部
・グラファイト ９０質量部
・第４級アンモニウム塩化合物（式３） ４０質量部
・上記球状炭素粒子Ａ ４０質量部
・メタノール １３０質量部
【０１６９】
【実施例１３】
実施例１の現像剤担持体の製造において、樹脂被膜層に用いる塗料を以下の処方により作製し、実施例１と同様にして現像剤担持体１３を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
・カーボン １０質量部
・グラファイト ９０質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％）５００質量部
・第４級アンモニウム塩化合物（式３） ４０質量部
・メタノール １００質量部
【０１７０】
下記材料を実施例１と同様に分散し、ＩＰＡ（イソプロピルアルコール）で固形分を３１％に調整し塗料を得た。
・カーボン １０質量部
・グラファイト ９０質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％）５００質量部
・球状炭素粒子Ａ ４０質量部
・ＩＰＡ １００質量部
この塗料を実施例１と同様にして現像担持体１４を作製し、実施例１と同様に画出し評価を行った。表３に塗料処方及び現像剤担持体の物性を示す。また、画出し評価結果を表４及び表５に示す。
【０１７１】
【比較例２】
実施例１において、上記式（３）で表される第４級アンモニウム塩化合物を上記式（２）で表される第４級アンモニウム塩化合物に変えて塗料を作製した以外は、現像剤担持体１５を得た。表３に塗料処方及び現像剤担持体の物性を示す。これを実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１７２】
なお、上記式（２）で表される第４級アンモニウム塩化合物について、実施例１と同様に鉄粉を用いたブローオフにより帯電量を測定したところ、負極性を示した。
【０１７３】
【比較例３】
クロルフェノールを含むアゾナフトールのクロム錯体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求めたところ、負極性であった。実施例１において、上記式（３）で表される第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とした以外は実施例１と同様にして、現像剤担持体（１６）を作製し、実施例１と同様に画出し評価を行った。表３に塗料処方及び現像剤担持体の物性を示す。画出し評価結果を表４及び表５に示す。
【０１７４】
【実施例１４〜１６】
＜磁性現像剤２の製造＞
磁性現像剤１の製造において、疎水化処理磁性体に代えて疎水化処理を行っていない磁性体９０質量部を用いた以外は同様にして磁性現像剤２を得た。磁性現像剤２の物性を表１に示す。
【０１７５】
実施例１〜３で作製した現像剤担持体１〜３を上記で得た磁性現像剤２を用いて、実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１７６】
【比較例４】
比較例１で用いた現像剤担持体１４と上記磁性現像剤２を用いて、実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１７７】
【比較例５】
比較例２で用いた現像剤担持体１５と上記磁性現像剤２を用いて、実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１７８】
【実施例１７〜１９】
＜磁性現像剤３の製造＞磁性現像剤２の製造において、ＴＫホモミキサーでの造粒後、６５℃で６時間、パドル攪拌翼にて攪拌後、８０℃に昇温させた後、懸濁液をアトライター（三井三池化工機（株））にて攪拌処理を行い、その後更に４時間反応させた後、８０℃で蒸留を行った。磁性現像剤１の製造と同様にして、負帯電性の磁性現像剤３を得た。得られた磁性現像剤３の物性を表１に示す。
【０１７９】
実施例１〜３で作製した現像剤担持体１〜３を上記で得た磁性現像剤３を用いて、実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１８０】
【比較例６および７】
比較例１で用いた現像剤担持体１４と上記磁性現像剤３を用いて、実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１８１】
【比較例８、９】
＜磁性現像剤４の製造＞下記材料をブレンダーにて混合し、１３０℃に加熱した二軸エクストルーダーで溶融混練した。
・スチレン−ブチルアクリレート共重合樹脂 １００質量部
・不飽和ポリエステル樹脂 ２質量部
・飽和ポリエステル樹脂 ３質量部
・モノアゾ染料系のＦｅ化合物 １質量部
・疎水化処理磁性体 ９０質量部
冷却した混練物をハンマーミルで粗粉砕し、粗粉砕を気流分級機と衝突式気流粉砕機を有する粉砕手段で微粉砕した。得られた微粉砕物を粉体供給部に圧縮エアを用いた強制粉体分散装置を内蔵しているコアンダ効果を用いた多分割分級機にて、１．９６×１０^-1ＭＰａの圧縮エアで強制的に分散させながら供給し、厳密に分級して磁性現像剤４を得た。磁性現像剤４の物性を表１に示す。
【０１８２】
実施例１および２で作製した現像剤担持体１、２を上記磁性現像剤４を用いて実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１８３】
【比較例１０および１１】
比較例１で用いた現像剤担持体１４または比較例２で用いた現像剤担持体１５と、上記磁性現像剤４とを用いて、実施例１と同様に画出し評価を行った。結果を表４及び表５に示す。
【０１８４】
【実施例２０】
＜現像剤５の製造＞反応容器のイオン交換水１００００質量部に０．１Ｍ−Ｎａ₃ＰＯ₄水溶液１０００質量部ならびに１Ｍ−ＨＣｌ水溶液８５質量部を投入し、Ｎ₂パージしながら６５℃で６０分保温した。ＴＫ式ホモミキサーを用いて、１２００
０ｒｐｍにて撹拌しながら、１０Ｍ−ＣａＣｌ₂水溶液６０質量部を一括投入し、ｐＨ６
．５のＣａ₃（ＰＯ₄）₂を含む水系媒体を調製した。
【０１８５】
別容器中で下記材料を６５℃に保温し、ＴＫ式ホモミキサーを用いて、１２０００ｒｐｍにて均一に溶解、分散した。
・スチレン ８０質量部
・n-ブチルアクリレート ２０質量部
・カーボンブラック ７質量部
・ポリエステル樹脂 ５．５質量部
・サリチル酸金属化合物 １質量部
・エステルワックス １５質量部
・架橋剤（ジビニルベンゼン） ０．２５質量部
これに重合開始剤２，２’−アゾビス（２，４−ジメチルバレロニトリル）４質量部を溶解し、重合性単量体組成物を調製した。反応容器中の前記水系媒体中に上記重合性単量体組成物を投入し、６５℃、Ｎ₂パージ下において、ＴＫ式ホモミキサー（特殊機化工業製）にて１００００ｒｐｍで１０分間攪拌し、重合性単量体組成物を造粒した。その後、パドル攪拌翼にて攪拌しつつ６５℃で６時間反応させた。その後、液温を８０℃に昇温し、更に９時間攪拌を続けた。反応終了後、８５℃で蒸留を行った。重合反応終了後、懸濁液を冷却し、塩酸を加えてＣａ₃（ＰＯ₄）₂を溶解し、濾過、水洗、乾燥を行い、現像剤粒子を得た。
【０１８６】
この現像剤粒子の断面をＴＥＭにより観察したところ、離型剤は外殻樹脂に良好に内包されていた。得られた現像剤粒子１００質量部に疎水性酸化チタン微粉体１．５質量部を混合し、負帯電性の現像剤５を得た。得られた現像剤の円相当個数平均径Ｄ１は４．９μｍであった。現像剤５の物性を表１に示す。
＜現像剤担持体１７の製造＞
下記材料を実施例１と同様にして直径２ｍｍのジルコニア粒子にて３時間サンドミルを用いて分散を行い、塗料を得た。
・カーボン ２０質量部
・グラファイト ８０質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％）４００質量部
・第４級アンモニウム塩化合物（式（３））４０質量部
・メタノール １５０質量部
この塗料をスプレー法にて直径２０ｍｍのアルミニウム円筒体上に約１１μｍの被膜を形成させ、次いで熱風乾燥器により１５０℃／３０分間加熱・硬化させ、樹脂被膜層を有する現像剤担持体１７を作製した。表３に塗料処方及び現像剤担持体の物性を示す。
【０１８７】
この現像剤担持体をクリエイティブプロセッサー６６０（キヤノン製複写機）の改造機に組込み、上記現像剤５を用いて画出し評価を行った。結果を表６及び表７に示す。
【０１８８】
【表６】

【０１８９】
【表７】

【０１９０】
【比較例１２】
＜現像剤６の製造＞現像剤６の製造において、ＴＫホモミキサーでの造粒後、６５℃で６時間、パドル攪拌翼にて攪拌後、８５℃に昇温させた後、懸濁液をアトライター（三井三池化工機（株））にて攪拌処理を行い、その後更に９時間反応させた後、８５℃で蒸留を行った。磁性現像剤３の製造と同様にして、得られた現像剤粒子１００質量部に疎水性酸化チタン微粉体１．５質量部を混合し、負帯電性の現像剤６を得た。得られた現像剤６の円相当個数平均径Ｄ１は５．１μｍであった。現像剤６の物性を表１に示す。
【０１９１】
実施例２０で作製した現像剤担持体１７を上記で得た現像剤６を用いて、実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９２】
【実施例２１】
実施例２０において、上記式（３）で表される第４級アンモニウム塩化合物の添加量を４０質量部から６０質量部に変えて塗料を作製した以外は、実施例２０と同様にして現像剤担持体１８を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体１８と現像剤５を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９３】
【比較例１３】
現像剤担持体１８と現像剤６を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９４】
【実施例２２】
実施例２０において、上記式（３）で表される第４級アンモニウム塩化合物の添加量を４０質量部から１０質量部に変えて塗料を作製した以外は、実施例２０と同様にして現像剤担持体１９を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体１９と現像剤５を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９５】
【比較例１４】
現像剤担持体１９と現像剤６を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９６】
【実施例２３】
実施例１の現像剤担持体の製造において、樹脂被膜層に用いる塗料を以下の処方により作製し、実施例１と同様にして現像剤担持体２０を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体２０と現像剤５を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
・カーボン ２０質量部
・グラファイト ８０質量部
・アンモニアを触媒として製造された
フェノール樹脂中間体（固形分５０％） ４００質量部
・第４級アンモニウム塩化合物（式３） ４０質量部
・上記球状炭素粒子Ａ ４０質量部
・メタノール １５０質量部
【０１９７】
【実施例２４】
実施例２０において、上記式（３）で表される第４級アンモニウム塩化合物の代わりに上記式（４）で表される第４級アンモニウム塩化合物を用いて塗料を作製した以外は、実施例２０と同様にして現像剤担持体２１を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体２１と現像剤５を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９８】
【比較例１５】
実施例２０において、上記式（３）で表される第４級アンモニウム塩化合物の代わりに上記式（６）で表される第４級アンモニウム塩化合物を用いて塗料を作製した以外は、実施例２０と同様にして現像剤担持体２２を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体２２と現像剤５を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０１９９】
【比較例１６】
実施例２０において、上記式（３）で表される第４級アンモニウム塩化合物の代わりに比較例３で用いたクロルフェノールを含むアゾナフトールのクロム錯体を用いて塗料を作製した以外は、実施例２０と同様にして現像剤担持体２３を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体２３と現像剤５を用いて実施例２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０２００】
【比較例１７】
実施例２０において、上記式（３）で表される第４級アンモニウム塩化合物の代わりに比較例３で用いたクロルフェノールを含むアゾナフトールのクロム錯体を用いて塗料を作製した以外は、実施例２０と同様にして現像剤担持体２３を得た。表３に塗料処方及び現像剤担持体の物性を示す。現像剤担持体２３と現像剤５を用いて実施例
２０と同様に画出し評価を行った。結果を表６及び表７に示す。
【０２０１】
【比較例１８】
導電性樹脂被覆層を形成しないで、粒径＃３００のガラスビーズを用いて基体表面をブラストした直径２０ｍｍＦＧＢスリーブを現像剤担持体２５として用いた以外は、実施例２０と同様にして現像剤５を用いて画出し評価を行った。結果を表６及び表７に示す。
【０２０２】
【発明の効果】
以上説明したように、本発明によれば、フロー式粒子像測定装置で計測される現像剤の平均円形度が０．９２０〜０．９９５であり、円形度標準偏差が０．０４５以下である負帯電性現像剤を用いる場合において、現像剤担持体基体上に形成された樹脂被覆層を、少なくとも被覆層用結着樹脂と、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含有し、前記樹脂被覆層は少なくとも被覆層用結着樹脂からなり、前記被覆層用結着樹脂の一部又は全てが、その分子構造中に、−ＮＨ ₂ 基、＝ＮＨ基、も
しくは−ＮＨ−結合のいずれかを少なくとも有する被覆層用結着樹脂であることを特徴とすることで、現像剤に対して過剰帯電（チャージアップ）させることなく安定して適切な帯電付与を行うことができ、負帯電性現像剤を好適なトリボにコントロールすることのできる現像方法、現像装置および画像形成装置が提供できる。
【０２０３】
さらには重合法により製造されたチャージアップしやすく、従来安定した帯電付与が困難であった現像剤を用いた場合においても、好適なトリボにコントロールすることのできる現像方法、現像装置および画像形成装置が提供できる。
【０２０４】
また、現像剤に対して電荷をチャージアップさせにくく、異なる環境下においても安定して適切な帯電付与を行うことができる構成であるため、現像剤担持体表面への融着防止など耐汚染性に優れ、スジムラやゴースト、ブロッチの現れない高品位な画像を長期の画出し耐久においても、安定して提供することができる。
【図面の簡単な説明】
【図１】一成分磁性現像剤を用いる本発明の現像装置の構成例を示す模式図である。
【図２】一成分磁性現像剤を用いる本発明の現像装置の構成例を示す模式図である。
【図３】一成分磁性現像剤を用いる本発明の現像装置の構成例を示す模式図である。
【図４】一成分非磁性現像剤を用いる本発明の現像装置の構成例を示す模式図である。
【図５】一成分非磁性現像剤を用いる本発明の現像装置の構成例を示す模式図である。
【図６】一成分非磁性現像剤を用いる本発明の画像形成装置の構成例を示す模式図である。
【符号の説明】
１ 電子写真感光ドラム（像担持体）
２ 磁性規制部材
３ ホッパー
４ 現像剤
６ 金属製円筒管（基体）
７ 導電性樹脂被膜層
８ 現像スリーブ（現像剤担持体）
９ 電源
１０ 攪拌翼
１１ 間隙
１２ 現像剤層厚規制部材
１２’現像剤層厚規制部材
１３ 非磁性現像剤
１４ 金属棒
１５ 金属円筒管
１６ 供給剥ぎ取り部材
１７ 接触帯電手段
１８ 露光
１９ 接触転写手段
２０ 電圧印加手段
２１ 加熱加圧ローラ定着装置
２２ クリーニングブレード
２３ クリーニング手段
２４ イレース露光[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a developing method for developing a latent image formed on an image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric to make it visible.Development deviceAnd an image forming apparatus using the same.
[0002]
[Prior art]
Conventionally, many methods are known as electrophotographic methods. Generally, a photoconductive substance is used to form an electrostatic latent image on an image carrier (photosensitive member) by various means, and then the electrophotographic method is performed. The latent image is developed with a developer to make it visible, and if necessary, the toner image is transferred to a transfer material such as paper. Then, the toner image is fixed on the transfer material by heat, pressure, etc. To get.
[0003]
Development methods in electrophotography are mainly divided into a one-component development method using a one-component developer and a two-component development method using a two-component developer. In recent years, since it is necessary to reduce the size of a copying apparatus for the purpose of reducing the weight and size of an electrophotographic apparatus, a developing apparatus using a one-component developer is often used.
[0004]
The one-component development method does not require carrier particles such as glass beads or iron powder unlike the two-component development method, and therefore the development device itself can be reduced in size and weight. Furthermore, since the two-component development method needs to keep the toner concentration in the developer constant, a device for detecting the toner concentration and supplying a necessary amount of toner is necessary. Therefore, the developing device is also large and heavy here. Since such a device is not necessary in the one-component development method, it is preferable because it can be made small and light.
[0005]
For example, as developing means using a one-component developer, an electrostatic latent image is formed on the surface of a photosensitive drum as an image carrier, and the friction between the developing sleeve and the developer as the developer carrier and / or the developing sleeve. The developer is applied with a positive or negative charge by friction between the developer regulating member for regulating the developer coating amount and the developer, and the developer is applied thinly on the developing sleeve so that the photosensitive drum and the developing sleeve are separated from each other. It is known that the developer is transported to an opposing development area, and the developer is developed by flying and adhering to the electrostatic latent image on the surface of the photosensitive drum in the development area to develop the electrostatic latent image as a toner image. .
[0006]
Also, LED and LBP printers are the mainstream in the recent market as printer devices, and the direction of technology is higher resolution, that is, the conventional 300, 400 dpi has become 600, 800, 1200 dpi. Accordingly, the development method is required to have a higher definition. In addition, copying machines are becoming more sophisticated, and thus are moving toward digitalization. In this direction, the method of forming an electrostatic latent image with a laser is the main method, so it is also proceeding in the direction of high resolution. Here, as with printers, a high-resolution and high-definition development method has been required. In JP-A-1-112253, JP-A-2-284158, and the like, a developer having a small particle size is proposed, and the particle size of the developer is further reduced with the recent further improvement in image quality. Is needed.
[0007]
However, as the particle size measured with a Coulter counter becomes 9 μm or less, it is extremely possible to classify the developer into uniform dispersion of raw materials used, high pulverization efficiency, and sharp particle size distribution, which were not problematic in the past. It tends to be difficult.
[0008]
  In order to overcome the problems of the developer due to the pulverization method, it was produced by a suspension polymerization method disclosed in Japanese Patent Publication No. 36-10231, Japanese Patent Publication No. 43-10799, Japanese Patent Publication No. 51-14895, and the like. Developers have come into practical use. Suspension polymerizationIsAfter the polymerizable monomer, colorant, polymerization initiator and, if necessary, the crosslinking agent, charge control agent, and other additives are uniformly dissolved or dispersed to form a monomer composition, this monomer In this method, a composition having a desired particle size is obtained by dispersing the composition in a continuous phase containing a dispersion stabilizer, such as an aqueous phase, using a suitable stirrer and simultaneously carrying out a polymerization reaction.
[0009]
Since this manufacturing method does not go through a pulverization step, it is not necessary to impart brittleness to the developer, and further, a material that can use a large amount of a low softening point material that could not be used in the conventional pulverization method. The range of choices expands.
[0010]
The polymerization method also has an excellent characteristic that a developer having a sharp particle size distribution and a fine particle size can be produced relatively easily.
[0011]
However, in a developing device using a developer by a polymerization method, a relatively thin and uniform toner layer must be formed on the developer carrier. However, the formation of the toner layer depends on the environmental conditions, the physical properties of the developer, the developer Depending on the state of the surface of the carrier, etc., unevenness is often generated particularly in a low humidity environment.
[0012]
Further, as the copying is repeated, the developer is repeatedly rubbed against the developer carrier, so that a non-developing substance such as an additive for improving the fluidity of the developer is deposited on the developing sleeve or in the developer. Since the low softening point material is deposited on the developer carrying member, the surface state of the developer carrying member changes, and the developability of the developer changes.
[0013]
Further, when the developer obtained by the direct polymerization method is used in such a developing apparatus, the developer obtained by the direct polymerization method has extremely good fluidity compared to the developer obtained by the pulverization method, so that the developer is There may be a phenomenon in which the developer carrying member and the regulating member slip through. For this reason, the charge amount between the developer particles tends to be non-uniform, and as a result of not being able to obtain a uniform coating, a defective image with background fog and image unevenness may occur. Furthermore, in repeated endurance image forming experiments, the developer enters the bearing and the like, and a fused product of the developer is generated, so that transfer defects are likely to occur during transfer.
[0014]
  In general, since the developer using direct polymerization is substantially spherical, it is easy to close-pack the developer in the developing device. In some cases, the developer is downstream of the developer layer thickness regulating member in the developing device.DenseTherefore, the mechanical load on the developer increases, and so-called sleeve contamination occurs in which the developer is fused on the developer carrying member. Sleeve contamination is undesirable because it causes a reduction in image density and fogging.
[0015]
In the case of using a polymerization method, it is difficult to adjust the developer charge, and various efforts have been made with the developer, but it is related to durability stability such as non-uniformity of developer charge and occurrence of fusion to the sleeve surface. The problem is not fully resolved.
[0016]
Furthermore, as the developing sleeve rotates repeatedly, the charge amount of the developer coated on the developing sleeve becomes too high due to the contact with the developing sleeve, and the developer is reflected by the mirror surface with the developing sleeve surface. When the so-called charge-up phenomenon occurs, the developer on the upper layer is less likely to be charged when it attracts and becomes immobile on the surface of the developing sleeve and does not move from the developing sleeve to the latent image on the electrostatic latent image holding member (drum). As a result, the development amount of the developer is reduced, which causes problems such as thin line images and thin image density of solid images.
[0017]
Further, since the toner layer formation state of the image portion (developer consumption portion) and the non-image portion is changed and the charging state is different, for example, the position where a solid image having a high image density is developed is next to the developing sleeve. When a halftone image is developed when the developing position is reached during rotation, a phenomenon that a solid image appears on the image, that is, a so-called sleeve ghost phenomenon is likely to occur.
[0018]
As a method for solving such a phenomenon, as disclosed in Japanese Patent Application Laid-Open No. 3-200986, as a developer carrier, a conductive fine powder such as a solid lubricant and carbon, and further spherical particles are dispersed in a resin. A method of using a developing sleeve provided with a conductive coating layer on a metal substrate in a developing device has been proposed. Although this method is effective in preventing the charge-up phenomenon and improving the uniformity of charging, the addition of a large amount of such a fine powder has the adverse effect of lowering the durability due to scraping of the developing sleeve surface layer. When the developer obtained by the polymerization method used in the present invention is used, even when this developing sleeve is used, the effect of preventing the charge-up phenomenon and improving the uniformity of charging is insufficient. Furthermore, in order to reduce the chargeability of the developer, a proposal has been made to add a material having the same polarity as that of the developer to the sleeve, but there is no one that can obtain a sufficiently satisfactory result. Therefore, further improvements such as prevention of charge-up phenomenon, improvement of charging uniformity, improvement of sleeve ghost phenomenon, suppression of developer contamination and developer fusion are desired.
[0019]
[Problems to be solved by the invention]
  Therefore, the object of the present invention is to solve the above-mentioned problems and to have a substantially spherical shape.PresentIt is an object to provide a developing method, a developing device, and an image forming apparatus that prevent a charge-up phenomenon when an image agent is used and have a quick and uniform charge imparting ability to the developer.
[0020]
Another object of the present invention is to provide a developing method, a developing apparatus, and an image capable of stably obtaining a high-quality image free from problems such as line image thinning, solid image density thinning, and sleeve ghost. A forming apparatus is provided.
[0021]
A further object of the present invention is to provide a developing method, a developing apparatus, and a developer device that can reduce the contamination of the developer and the fusion of the developer, have good durability, stabilize the charge level even during long-term image output, and stabilize the image performance. An image forming apparatus is provided.
[0022]
[Means for Solving the Problems]
The above object is achieved by the present invention described below.
[0023]
  That is, the present invention includes a step of supporting a developer contained in a developer container on a developer carrier, a step of regulating the layer thickness of the developer on the developer carrier by a developer layer thickness regulating member, A step of carrying and transporting the developer having a regulated layer thickness to a developing region where the developer carrying member and the image carrying member face each other; an electrostatic latent image on the image carrying member using the developer on the developer carrying member; And developing a visible image, wherein the developer has at least a binder resin and a colorant, and has an average circularity measured by a flow type particle image measuring device. Is 0.920 to 0.995, and the circularity standard deviation isA negatively chargeable developer of 0.045 or lessThe developer carrier comprises a substrate and a resin coating layer formed on the substrate, and the resin coating layer contains a quaternary ammonium salt compound that is positively charged with respect to at least iron powder.The resin coating layer is composed of at least a binder resin for the coating layer, and a part or all of the binder resin for the coating layer contains —NH ₂ At least one of the group, ═NH group, and —NH— bond
A binder resin for the coating layerThe developing method is characterized by the above.
[0024]
  Further, the present invention provides a developer, a developer carrier that carries and conveys the developer, a developer layer thickness regulating member that regulates the thickness of the developer layer on the developer carrier, and the layer thickness is regulated. A means for carrying and transporting the developer to a development area where the developer carrying body and the image carrying body face each other, and transferring the developer on the developer carrying body to an electrostatic latent image on the image carrying body, And a developing device having a visualizing means, wherein the developer has at least a binder resin and a colorant, and has an average circularity of 0.920 to 0 measured by a flow-type particle image measuring device. .995 and the circularity standard deviation isA negatively chargeable developer of 0.045 or lessThe developer carrier comprises a substrate and a resin coating layer formed on the substrate, and the resin coating layer contains a quaternary ammonium salt compound that is positively charged with respect to at least iron powder.The resin coating layer is composed of at least a binder resin for the coating layer, and a part or all of the binder resin for the coating layer contains —NH ₂ Group, = N
A binder resin for a coating layer having at least either an H group or an —NH— bondThis is a developing device.
[0025]
Furthermore, the present invention provides an image carrier for carrying an electrostatic latent image,
Charging means for applying a voltage to the charging member to charge the image carrier;
An electrostatic latent image forming means for forming an electrostatic latent image on a charged image carrier;
Developing means for transferring a developer carried on the developer carrier to an electrostatic latent image formed on the image carrier to form a toner image on the image carrier;
Transfer means for electrostatically transferring a toner image formed on the surface of the image carrier to a transfer material;
An image forming apparatus comprising: a fixing unit that heats and fixes the toner image transferred onto the transfer material;
The developing means is an image forming apparatus which is a developing device of the present invention.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
<1> Developer carrier in the present invention
Prior to the present invention, the inventors of the present invention disclosed a quaternary ammonium salt compound known as a positive charge control agent of a developer in JP-A-10-3204040 and JP-A-11-052711. That is, as a quaternary ammonium salt compound that is positively charged with respect to iron powder and a coating resin for a coating layer, a part or all of the coating resin for the coating layer is at least − in its molecular structure. NH₂When the resin coating layer of the triboelectric charging member is formed using a group having any of a group, ═NH group, and —NH— bond, a quaternary ammonium salt compound is incorporated into the binder resin for the coating layer, It has been found that the resin (resin layer) itself exhibits a strong negative chargeability and a good charge imparting property with respect to a positively chargeable developer. By using this as a friction charging member in a developing device, a very good image is obtained. We are proposing to obtain
[0027]
The advantage of this method is that it is used to form a resin layer, for example, compared to a conventional system in which silica, fluororesin powder, and a negative charge control agent are added to impart positive chargeability to the developer. Since the quaternary ammonium salt compound dissolves in the solvent of the binder resin for the coating layer and can be uniformly present in the resin, the entire resin coating layer becomes a uniform negatively chargeable material, like the silica addition system Compared to those dispersed in a matrix, the entire sleeve exhibits a uniform and good negative charge imparting property, and further, since it is not a powder addition system, it has a good mechanical strength, that is, durability. .
[0028]
In view of these points, as a result of various investigations, as a resin coating layer used for a development carrier, a quaternary ammonium salt compound known as a positive charge control agent of the conventional developer, that is, By adding an appropriate amount to the resin coating layer of the quaternary ammonium salt compound that itself is positively charged with respect to the iron powder, the coating layer binding resin can be further used as a coating layer binding resin. Some or all of the resin has -NH in its molecular structure₂A developer having a negative chargeability produced by a direct polymerization method by forming a resin coating layer of a developer carrier using a group having any of a group, ═NH group, and —NH— bond, It has been found that it is possible to effectively prevent the generation of an excessively charged developer and the strong adhesion of the developer to the surface of the developer carrying member, and to charge the triboelectric charge to a suitable level.
[0029]
In general, the developer produced by the direct polymerization method has the advantage that the transferability of the developer is greatly improved and the transfer efficiency is improved when compared with the developer produced by the conventional jet milling method. However, since a colorant such as carbon or a magnetic material used for a magnetic developer is taken into the inside of the particle, charges cannot be released on the surface of the developer particle, and it is easy to charge up. Therefore, development unevenness, blotches, and density reduction due to fixing of the developer sleeve are likely to occur. As a result of studies for improving the development characteristics of a developer produced by the direct polymerization method having the above-mentioned advantages, the charge amount of the developer is increased by configuring the resin coating layer of the developer carrier as described above. The inventors have found that it is possible to prevent the occurrence of image density reduction due to uneven development, blotch, and fog charge-up.
[0030]
  That is, the present invention is the development method, wherein the developer has at least a binder resin and a colorant, and the average circularity measured by a flow type particle image measuring device is 0.920 to 0.995,
Circularity standard deviation is0.045 or lessThe developer carrying member comprises a substrate and a resin coating layer formed on the substrate, and the resin coating layer is positively charged with respect to at least iron powder and contains a quaternary ammonium salt compound. This is a characteristic developing method.
[0031]
As the quaternary ammonium salt compound suitably used in the present invention, those having positive chargeability with respect to iron powder are used. For example, the compound represented by following formula (1) is mentioned.
[0032]
[Chemical 1]

(R in the formula¹, R², R³, R⁴Each represents an alkyl group which may have a substituent, an aryl group which may have a substituent, and an aralkyl group, and R¹~ R⁴May be the same or different. X⁻Represents an anion of an acid. )
  On the other hand, for example, a fluorine-containing quaternary ammonium salt compound that is negatively charged with respect to iron powder, as represented by the following formula (2), was also examined. It was found that the intended purpose was not achieved. The compound represented by the following formula (2) has a strong electron withdrawing property.SourceSince the child is in the structure, it has a negative chargeability with respect to the iron powder. Similarly to the case of the present invention, even if a developer carrying body in which a resin coating layer is formed on a carrier core material by heating and drying a resin composition in which the compound is dispersed in a binder resin for a coating layer, iron powder is used. However, the effect was not obtained to the extent that a quaternary ammonium salt compound that is positively charged was contained.
[0033]
[Chemical formula 2]

In addition, a resin coating of a developer carrier is obtained by adding the silica powder or a 3,5-di-t-butylsalicylic acid Cr complex, which is a typical negative charge control agent, into a binder resin for a coating layer. Even if it was used for the layer, the effect corresponding to the present invention was not obtained.
[0034]
Specific examples of the quaternary ammonium salt compound that is suitably used for the present invention and positively charged with respect to iron powder include those represented by the following formulas (3) to (10). The present invention is not limited to these.
[0035]
[Chemical Formula 3]

[0036]
[Formula 4]

[0037]
[Chemical formula 5]

[0038]
[Chemical 6]

[0039]
[Chemical 7]

[0040]
[Chemical 8]

[0041]
[Chemical 9]

[0042]
Embedded image

The addition amount of the quaternary ammonium salt compound as described above used for the resin coating layer of the developer carrying member in the present invention is 1 to 200 parts by mass with respect to 100 parts by mass of the binder resin for the coating layer. It is preferable. More preferably, it is 2-100 mass parts with respect to 100 mass parts of binder resin for coating layers. If the amount is less than 1 part by mass, the effect of controlling the chargeability by addition is not observed. If the amount exceeds 200 parts by mass, the existing amount in the binder resin for the coating layer becomes excessive and the properties of the original resin are impaired, resulting in a decrease in coating strength. It is easy to invite.
[0043]
The binder resin for the coating layer used in the coating layer of the present invention is not particularly limited, but a part or all of the binder resin for the coating layer has at least —NH in its molecular structure.₂It preferably has any structure of a group, ═NH group, or —NH— bond. By forming the coating layer using such a resin, the effects of the present invention can be easily exhibited. In the present invention, if the resin coating layer having the above-described configuration is used as the resin coating layer of the developer carrier, the clear reason for the resin coating layer itself changing to a negative charge imparting property is not clear, but iron A quaternary ammonium salt compound that is positively charged to the powder and -NH₂In the structure of the binder resin for coating layers, a resin coating layer is formed using a binder resin for coating layers having at least one structure of a group, = NH group, or -NH- bond. A quaternary ammonium salt is incorporated. At that time, the original structure of the quaternary ammonium salt having positive polarity is lost, and the charging property of the coating layer binder resin incorporating these becomes uniform and sufficiently negatively charged, so that the charging is stabilized. It is thought to contribute to this.
[0044]
-NH₂As the substance having a group, R-NH₂Or a polyamine having them, RCO-NH₂As the substance having ═NH group, such as a primary amide represented by the formula (I) or a polyamide having them, a secondary amine represented by R═NH or a polyamine having them,₂Examples of substances having —NH— bonds such as secondary amides represented by ═NH or polyamides having them include polyurethanes having —NHCOO— bonds in addition to the polyamines and polyamides described above. An industrially synthesized resin containing one or more of these as a copolymer or a copolymer is suitably used. Specifically, from the viewpoint of versatility, a phenol resin, a polyamide resin, or a urethane resin produced by adding and condensing phenols and aldehydes using a nitrogen-containing compound as a catalyst is particularly preferable.
[0045]
Examples of the nitrogen-containing compound used as a catalyst in the present invention include acidic catalysts and basic catalysts. Examples of acidic catalysts include ammonium sulfate, ammonium phosphate, ammonium sulfamate, ammonium carbonate, ammonium acetate, and ammonium maleate. Examples thereof include ammonium salts and amine salts. 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 , Amination of diethylethanolamine, ethyldiethanolamine, n-butyldiethanolamine, di-n-butylethanolamine, triisopropanolamine, ethylenediamine, hexamethylenetetramine, etc. Pyridine, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine and other pyridines and their derivatives, quinoline compounds, imidazole, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl Examples include imidazole such as -4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecylimidazole, and derivatives thereof.
[0046]
  As other binder resin materials for the coating layer, generally known resins can be used. For example, thermoplastic resins such as styrene resins, vinyl resins, polyethersulfone resins, polycarbonate resins, polyphenylene oxide resins, polyamide resins, fluororesins, fiber resins, acrylic resins, epoxy resins, polyester resins, alkyd resins , Phenolic resin, melamine resin, polyurethane resin, urea resin,Silicone resinFurther, heat or photo-curing resin such as polyimide resin can be used. Above allSilicone resinThose having releasability such as fluororesin, or those having excellent mechanical properties such as polyethersulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin, acrylic resin, etc. preferable. However, in order to easily achieve the configuration of the present invention, as described above, —NH₂It is preferable to use a binder resin for a coating layer having at least one structure of a group, ═NH group, or —NH— bond. Also, -NH₂A binder resin for a coating layer having at least one structure of a group, ═NH group, or —NH— bond may be used by mixing with the above general binder resin for a coating layer.
[0047]
In the developer carrier used in the present invention, conductive fine powder may be dispersed and contained in the binder resin for the coating layer in order to adjust the volume resistance of the resin coating layer. As such a conductive fine powder, the number average particle diameter is preferably 20 μm or less, and more preferably 10 μm or less. In order to avoid unevenness formed on the resin surface, the one having a number average particle diameter of 1 μm or less is used.
[0048]
  The conductive fine powder used in the present invention includes carbon black such as furnace black, lamp black, thermal black, acetylene black, channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide, potassium titanate, antimony oxide. And metal oxides such as indium oxide; metals such as aluminum, copper, silver and nickel; and inorganic fillers such as graphite, metal fibers and carbon fibers. As an addition amount of the conductive fine powder in the resin coating layer described above, a preferable range is 200 parts by mass or less with respect to 100 parts by mass of the binder resin for coating layer. A more preferable addition amount is 100 parts by mass or less. When the addition amount exceeds 200 parts by mass, the film strength is likely to decrease, and a large amountConductive fine powderThe addition of may reduce the charge amount of the developer.
[0049]
The resin coating layer of the developer carrying member used in the present invention is preferable because the effect of the present invention is further promoted by dispersing a lubricating substance in the coating resin layer. Examples of the lubricating substance include graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, and fatty acid metal salts such as zinc stearate. Is preferably used because it does not impair the conductivity of the coating layer. These lubricating substances preferably have a number average particle diameter of preferably about 0.2 to 20 μm, more preferably 0.3 to 15 μm. As the addition amount of the lubricating substance, a particularly preferable result is given in the range of 10 to 120 parts by mass with respect to 100 parts by mass of the binder resin for the coating layer. When the addition amount exceeds 120 parts by mass, the coating strength is likely to be reduced, and when a large amount of non-chargeable additive is added, the charge amount of the developer is reduced. On the other hand, if it is less than 10 parts by mass, it is difficult to obtain the effect of preventing the developer from adhering to the developer carrying member.
[0050]
Next, the configuration of the developer carrying member used in the present invention will be described.
[0051]
  The developer carrier comprises a substrate and a resin coating layer surrounding and covering the substrate. Examples of the shape of the substrate include a cylindrical member, a columnar member, and a belt-like member. In the developing method without contact with the drum, a cylindrical member is preferably used, and specifically, a metal cylindrical tube is preferably used. As the metal, nonmagnetic materials such as stainless steel, aluminum and alloys thereof are preferably used. Further, as a substrate in the development method in which the drum is brought into direct contact, urethane, EPDM,siliconeA cylindrical member having a layer structure including rubber or elastomer such as is preferably used.
[0052]
When a magnetic developer is used, a magnet roller or the like in which a magnet is provided is disposed in the developer carrying body in order to magnetically attract and hold the developer on the developer carrying body. In that case, the substrate may be cylindrical and a magnet roller may be disposed inside the substrate. On the other hand, when a nonmagnetic developer is used, it is not necessary to enclose a magnet.
[0053]
The developer-carrying resin coating layer is obtained by dispersing spherical particles having a number average particle size of 0.3 to 30 μm in the coating resin layer in addition to the above-mentioned additive substances such as the conductive fine powder and the lubricating substance. Is also preferable. Thereby, it is possible to stabilize the surface roughness and optimize the coating amount of the developer on the developer carrying member. The spherical particles maintain a uniform surface roughness on the surface of the resin coating layer of the developer carrying member, and at the same time, even when the surface of the resin coating layer is worn, there is little change in the surface roughness of the resin coating layer. This has the effect of making it difficult for contamination and developer fusion to occur.
[0054]
The spherical particles used in the present invention have a number average particle size of 0.3 to 30 μm, preferably 2 to 20 μm. If the number average particle size of the spherical particles is less than 0.3 μm, the effect of imparting uniform roughness to the surface and the effect of stabilizing the charging performance thereby are small, and the rapid and uniform charging to the developer becomes insufficient. Tend. In addition, developer transport becomes unstable, and transportability is further reduced by coating layer wear, resulting in developer charge-up, developer contamination, and developer fusion, resulting in ghost deterioration and image density reduction. This is not preferable because When the number average particle diameter exceeds 30 μm, the surface roughness of the coating layer becomes too large, the developer transport amount becomes large, and it is difficult to sufficiently regulate the developer regulating section. Charging is difficult to perform sufficiently, causing problems such as image quality degradation and inversion fog. Furthermore, it is not preferable because the mechanical strength of the coating layer decreases and the durability of the film decreases.
[0055]
More preferably, the true density of the spherical particles is 3 g / cm.^ThreeOr less, preferably 2.7 g / cm^ThreeOr less, more preferably 0.9 to 2.3 g / cm^ThreeIt is good to be. That is, the true density of the spherical particles is 3 g / cm.^ThreeIn the case where it exceeds 1, the dispersibility of the spherical particles in the coating layer becomes insufficient, so that it becomes difficult to impart uniform roughness to the surface of the coating layer. Also, since the storage stability of the paint is not good, it is difficult to obtain the surface of the triboelectric charge imparting member having uniform surface irregularities. The true density of the spherical particles is 0.9 g / cm^ThreeEven if it is smaller, the dispersibility and storage stability of the spherical particles in the coating layer become insufficient.
[0056]
In the present invention, the spherical shape in the spherical particles means a particle having a major axis / minor axis ratio of about 1.0 to 1.5. In the present invention, the ratio of major axis / minor axis is preferred. It is preferable to use particles having a particle size of 1.0 to 1.2. When the ratio of the major axis / minor axis of the spherical particles exceeds 1.5, the coating layer surface roughness becomes uneven, the developer is rapidly and uniformly charged, and the strength of the conductive resin coating layer is increased. It is not preferable in terms.
[0057]
As the spherical particles used in the present invention, known spherical particles can be used. Examples include spherical resin particles, spherical metal oxide particles, and spherical carbonized particles. As the spherical particles, for example, spherical resin particles produced by suspension polymerization, dispersion polymerization, or the like are used. Spherical resin particles can obtain a suitable surface roughness with a smaller addition amount, and a uniform surface shape can be easily obtained. Specifically as spherical resin particles, acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, phenolic resin particles, Examples include polyurethane resin particles, styrene resin particles, and benzoguanamine particles. The resin particles obtained by the pulverization method may be used after thermally or physically spheroidizing.
[0058]
In addition, inorganic fine powder may be adhered or fixed to the surface of the spherical particles. Such inorganic fine powders include SiO₂, SrTiO_Three, CeO₂, CrO, Ai₂O_Three, ZnO, MgO and other oxides, Si_ThreeN_FourNitride such as SiC, carbide such as SiC, CaSO_Four, BaSO_Four, CaCO_ThreeAnd sulfates, carbonates and the like. Such inorganic fine powder may be used after being treated with a coupling agent. By treating the inorganic fine powder with a coupling agent, the adhesion of the spherical particles to the binder resin for the coating layer can be improved, or the spherical particles can be made hydrophobic.
[0059]
Examples of such a coupling agent include a silane coupling agent, a titanium coupling agent, and a zircoaluminate coupling agent. More specifically, for example, as a silane coupling agent, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, Benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyl Diethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltet Lamethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane containing 2 to 12 siloxane units per molecule and containing hydroxyl groups bonded to one silicon atom at each terminal unit Examples thereof include siloxane.
[0060]
By treating the surface of the spherical particles with the inorganic fine powder in this way, dispersibility in the coating layer, uniformity of the coating layer surface, stain resistance of the coating layer, charge imparting property to the developer, coating layer It is possible to improve the wear resistance and the like.
[0061]
  In addition, the spherical particles used in the present invention are preferably conductive. That is, by imparting conductivity to the spherical particles, it is difficult to accumulate charges on the particle surface due to the conductivity, and it is possible to reduce the adhesion of the developer and improve the charge imparting property to the developer. In the present invention, the volume resistance value is 10 as the conductivity of the spherical particles.⁶Ω · cm or less, more preferably 10^-3-10⁶The particles are preferably Ω · cm. Volume resistance of spherical particlesvalue10⁶If it exceeds Ω · cm, the developer is likely to be contaminated and fused with spherical particles exposed on the surface of the coating layer due to wear, and it becomes difficult to perform rapid and uniform charging.
[0062]
As a method for obtaining such conductive spherical particles, the following methods are preferable, but are not necessarily limited to these methods.
[0063]
As a method for obtaining particularly preferable conductive spherical particles used in the present invention, for example, low density and good conductive properties obtained by carbonizing and / or graphitizing by firing resin-based spherical particles and mesocarbon microbeads. The method of obtaining spherical carbon particles is mentioned. Examples of the resin used for the resin-based spherical particles include phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile, and the like. In addition, mesocarbon microbeads can be usually produced by washing spherical crystals formed in the process of heating and firing the medium pitch with a large amount of solvents such as tar, medium oil, and quinoline.
[0064]
More preferable methods for obtaining conductive spherical particles include a mechanochemical method on the surface of spherical resin particles such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile. And a method of obtaining conductive spherical carbon particles by coating the bulk mesophase pitch with, and heat-treating the coated particles in an oxidizing atmosphere, followed by firing in an inert atmosphere or vacuum to carbonize and / or graphitize. It is done. Spherical carbon particles obtained by this method are more preferred because they improve the conductivity because the crystallization of the coating of the spherical carbon particles obtained by the graphitization proceeds.
[0065]
The conductive spherical carbon particles obtained by the above-described method can control the conductivity of the obtained spherical carbon particles by changing the firing conditions in any method, and are preferably used in the present invention. The In addition, in some cases, the spherical carbon particles obtained by the above method have a true density of the conductive spherical particles of 3 g / cm in order to further increase the conductivity.^ThreeThe conductive metal and / or metal oxide may be plated within a range not exceeding.
[0066]
As another method for obtaining the conductive spherical particles used in the present invention, the conductive fine particles having a particle size smaller than the particle size of the core particles with respect to the core particles made of the spherical resin particles are machined at an appropriate blending ratio. When the conductive particles are uniformly mixed around the core particles by the action of van der Waals force and electrostatic force, the core is increased due to a local temperature rise caused by, for example, applying mechanical impact force. Examples thereof include a method of obtaining spherical resin particles obtained by softening the particle surface, forming conductive fine particles on the core particle surface, and conducting the conductive treatment.
[0067]
Still another method for obtaining the conductive spherical particles used in the present invention is to obtain conductive spherical particles in which the conductive fine particles are dispersed by uniformly dispersing the conductive fine particles in the spherical resin particles. Can be mentioned. As a method for uniformly dispersing the conductive fine particles in the spherical resin particles, for example, the binder resin for spherical particles and the conductive fine particles are kneaded to disperse the conductive fine particles, and then cooled and solidified, A method of obtaining conductive spherical particles by pulverizing to a particle size and spheronizing by mechanical treatment and thermal treatment; or a polymerization initiator, conductive fine particles and other additives in a polymerizable monomer for spherical particles The monomer composition uniformly dispersed by a disperser is suspended in an aqueous phase containing a dispersion stabilizer so as to have a predetermined particle diameter by a stirrer or the like, and polymerization is performed. To obtain spherical particles in which is dispersed.
[0068]
  The method for forming the resin coating layer of the present invention is not particularly limited, and can be performed by a normal method. For example, the developer carrierSubstrateIn addition, the developer of the present invention can be obtained by applying a coating solution containing the binder resin for a coating layer and the quaternary ammonium salt compound by a method such as dipping, spraying or brushing and drying. A carrier is obtained.
[0069]
  The developer used in the present invention has at least a binder resin and a colorant, and has an average circularity of 0.920 to 0.995 measured by a flow-type particle image measuring device, with a circularity standard deviation. But0.045 or lessIt is.
[0070]
In addition, the number-based circle equivalent diameter-circularity scattergram measured by the follow-type particle image measuring apparatus has a circle-equivalent number average diameter D1 of 2 to 10 μm.
[0071]
The equivalent circle diameter, circularity, and particle size distribution of the developer in the present invention are used as a simple method for quantitatively expressing the shape of the developer particles. In the present invention, manufactured by Toa Medical Electronics Co., Ltd. Measurement is performed using a flow type particle image measuring apparatus FPIA-1000, and calculation is performed using the following formula (I) and the following formula (II).
[0072]
[Expression 1]

Here, the particle projected area is the area of the binarized developer particle image, and the peripheral length of the particle projected image is defined as the length of the contour line obtained by connecting the edge points of the developer particle image.
[0073]
In the present invention, the circularity is an index indicating the degree of unevenness of the developer particles, and is 1.000 when the developer particles are completely spherical. The more complicated the surface shape, the smaller the circularity. .
[0074]
In the present invention, the circle-equivalent number average diameter D1 and the particle size standard deviation SDd, which mean the average value of the number-based particle size frequency distribution of the developer, are expressed as di (center value) at the dividing point i of the particle size distribution. When the frequency is fi, it is calculated from the following equations (III) and (IV).
[0075]
[Expression 2]

In addition, the average circularity c and the circularity standard deviation SDc, which mean the average value of the circularity frequency distribution, are expressed by the following equation when the circularity (center value) at the dividing point i of the particle size distribution is ci and the frequency is fci: Calculated from V) and (VI).
[0076]
[Equation 3]

As a specific measurement method, 10 ml of ion-exchanged water from which impure solids and the like have been removed in advance is prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, followed by further measurement. Add 0.02 g of sample (developer) and disperse uniformly. As a means for dispersion, an ultrasonic disperser “UH-50 type” (manufactured by SMT Corporation) equipped with a titanium alloy chip having a diameter of 5 mm as a vibrator is used. And In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more.
[0077]
To measure the shape of the developer particles, the flow particle image measuring device is used, and the dispersion concentration is readjusted so that the developer particle concentration at the time of measurement is 3000 to 10,000 particles / μl. 1000 or more are measured. After the measurement, the data is used to determine the equivalent circle diameter of the developer particles, the circularity frequency distribution, and the like.
[0078]
Conventionally, there are several apparatuses that can measure a particle size of 1.0 μm or less, but noise is greatly affected in a region of 1.0 μm or less, and there is a problem in data reproducibility. This apparatus is excellent in that reproducibility is good even in an area of 1.0 μm or less, and since information as a particle image can be obtained at the same time, particles can be confirmed.
[0079]
In the developer-based number equivalent circle diameter-circularity scattergram measured by the flow type particle image measuring device, the circle equivalent number average diameter D1 of the developer is 2 to 10 μm, and the developer The average circularity is preferably 0.920 to 0.995, and the circularity standard deviation is preferably less than 0.040. More preferably, the average circularity is 0.965 to 0.990, and the circularity standard deviation is less than 0.035. In the developer-based circle equivalent diameter-circularity scattergram measured by the flow type particle image measuring device, the developer may have 15 or less number of developer particles having a circularity of less than 0.950. preferable.
[0080]
By reducing the circle-equivalent number average diameter D1 of the developer to 2 to 10 μm, the reproducibility in the development of the contour portion of the image, particularly the character image or the line pattern is improved. However, in general, when the developer particle size is reduced, the abundance of the fine particle developer inevitably increases, so that it is difficult to uniformly charge the developer, causing image fogging, and electrostatic latent image. Adhesive force to the surface of the carrier and the developer carrier tends to increase.
[0081]
The method for producing the developer used in the present invention is not particularly limited, but the suspensions described in JP-B-36-10231, JP-A-59-53856, and JP-A-59-61842 are described. A method of directly producing a developer using a polymerization method, an emulsion weight represented by a soap-free polymerization method in which a monomer is directly polymerized in the presence of a water-soluble polymerization initiator soluble in a monomer to produce developer particles. Examples include the production of developer particles by a legal method. In addition, production by an interfacial polymerization method such as a microcapsule production method, an in-site polymerization method, a coacervation method, or the like is also included. Furthermore, as disclosed in JP-A-62-106473 and JP-A-63-186253, an interfacial polymerization method for aggregating at least one kind of fine particles to obtain a particle having a desired particle diameter is also mentioned. It is done. Among these, the suspension polymerization method is particularly preferable because a developer having a small particle diameter can be easily obtained. Further, a seed polymerization method in which a monomer is further adsorbed to the polymer particles once obtained and then polymerized using a polymerization initiator can be suitably used. In this case, a polar compound can be dispersed or dissolved in the monomer to be adsorbed.
[0082]
When the suspension polymerization method is used as a method for producing developer particles, specifically, developer particles can be produced directly by the following production method. Add a release agent such as wax, a colorant, a polymerization initiator, a crosslinking agent, and other additives to the polymerizable monomer that can be a binder resin, and dissolve or disperse it uniformly with a homogenizer, ultrasonic disperser, etc. The polymerizable monomer composition thus obtained is dispersed in an aqueous medium containing a dispersion stabilizer by a usual stirrer, homomixer, homogenizer or the like.
[0083]
Preferably, granulation is performed by adjusting the stirring speed and time so that the droplets of the polymerizable monomer composition have the desired developer particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained by the action of the dispersion stabilizer and the sedimentation of the particles is prevented. The polymerization is carried out at a polymerization temperature of 40 ° C. or higher, usually 50 to 90 ° C. (preferably 55 to 85 ° C.). The temperature may be raised in the latter half of the polymerization reaction, and the pH may be changed as necessary. Further, in order to remove unreacted polymerizable monomers and by-products that cause odor during fixing of the developer, a part of the aqueous medium may be distilled off in the latter half of the reaction or after the completion of the reaction. After completion of the reaction, the produced developer particles are collected by washing and filtration and dried.
[0084]
The following describes the materials of the polymerization method developer.
[0085]
Examples of the polymerizable monomer used when the developer used in the present invention is produced by a polymerization method include vinyl polymerizable monomers capable of radical polymerization. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.
[0086]
Monofunctional polymerizable monomers include styrene; α-methyl styrene, β-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, pn-butyl. Styrene, pt-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p -Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, t-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate, n-octyl Acrylic polymerizable monomers such as acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, Ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, t-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n- Nonyl methacrylate, diethyl phosphate ethyl methacrylate, dibutyl phosphate Methacrylic polymerizable monomers such as ethethyl methacrylate; Methylene aliphatic monocarboxylic acid ester; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl formate; Vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether And vinyl ketones such as vinyl ether, vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropyl ketone.
[0087]
  Multifunctional polymerizationsexAs monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol Diacrylate, 2,2'-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol Dimethacrylate, polyethylene glycol dimethacrylate 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxy-diethoxy) phenyl) propane, 2, Examples thereof include 2′-bis (4- (methacryloxy / polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, and divinyl ether.
[0088]
The above-mentioned monofunctional polymerizable monomers can be used alone or in combination of two or more, or the above-mentioned monofunctional polymerizable monomers and polyfunctional polymerizable monomers can be used in combination. The polyfunctional polymerizable monomer can also be used as a crosslinking agent.
[0089]
  Moreover, as a polymerization initiator used for this invention, an oil-soluble initiator and / or a water-soluble initiator are used. For example, as the oil-soluble initiator, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) Azo compounds such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile; acetylcyclohexylsulfonyl peroxide, diisopropylperoxycarbonate, decanonyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide Oxide, acetyl peroxide, t-butyl peroxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, Peroxide initiators such as Men hydroperoxide peroxide. Water-soluble initiators include ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-dimethyleneisobutyroamidine) hydrochloride, 2,2'-azobis (2-aminodinopropane) hydrochloric acidsalt,Azobis (isobutylamidine) hydrochloride, sodium 2,2'-azobisisobutyronitrile sulfonate, ferrous sulfate or hydrogen peroxide. Furthermore, in order to control the degree of polymerization of the polymerizable monomer, it is possible to add and use a chain transfer agent, a polymerization inhibitor or the like.
[0090]
As the cross-linking agent, in addition to the polyfunctional polymerizable monomer, a compound having two or more polymerizable double bonds is used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline; And divinyl ether, divinyl sulfide, divinyl sulfone and other divinyl compounds; and compounds having three or more vinyl groups. These are used alone or as a mixture.
[0091]
As the dispersion stabilizer used in the present invention, inorganic compounds and organic compounds can be used. As inorganic compounds, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate can be used. , Magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, hydroxyapatite and the like. Usually, it is preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the polymerizable monomer. As the organic compound, for example, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used. These dispersion stabilizers are preferably used in an amount of 0.2 to 2.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
[0092]
As the dispersion stabilizer more preferably used in the present invention, there are poorly water-soluble metal salts of sulfuric acid, carbonic acid, phosphoric acid, pyrophosphoric acid, and polyphosphoric acid, which are acid alkali metal salts and halogens under high-speed stirring in a dispersion medium. It is preferably prepared by reaction with a metal halide salt. In order to refine these dispersants, 0.001 to 0.1 parts by mass of a surfactant may be used in combination with 100 parts by mass of the polymerizable monomer. Specifically, commercially available nonionic, anionic and cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like are preferably used.
[0093]
  The release agent added to the polymerizable monomer when polymerizing the developer is preferably a weight average molecular weight (Mw) of 350 to 4000 and a number average molecular weight (Mn) of 200 to 4000. More preferably, Mw is 400-3500 and Mn is 250-3500. When Mw is less than 350 and Mn is less than 200, the blocking resistance of the developer tends to decrease. If Mw exceeds 4000 and Mn exceeds 4000, the crystallinity of the release agent itself is developed, and the transparency of the fixed image tends to decrease.The
[0094]
In the present invention, the molecular weight distribution of the release agent is measured by GPC under the following conditions.
Apparatus: GPC-150C (Waters)
Column: GMH-MT 30 cm 2 series (manufactured by Tosoh Corporation)
Temperature: 135 ° C
Solvent: o-dichlorobenzene (0.1% ionol added)
Flow rate: 1.0 ml / min
Sample: 0.4ml injection of 0.15% sample
Measurement is performed under the above conditions, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample is used in calculating the molecular weight of the sample. Furthermore, it is calculated by converting to polyethylene using a conversion formula derived from the Mark-Houwink viscosity formula.
[0095]
  The mold release agent has a melting point (temperature corresponding to the maximum endothermic peak of the DSC endothermic curve in the temperature range of 20 to 200 ° C) of 30 to 120 ° C, more preferably 50 to 90 ° C. As the mold release agent, a wax in a solid state at room temperature is preferable, and a solid wax having a melting point of 40 to 100 ° C. is particularly preferable in terms of blocking resistance of the developer, durability of a large number of sheets, low-temperature fixability, and offset resistance. Examples of waxes include paraffin wax, ketone wax, polyolefin wax, microcrystalline wax, and Fischer-Tropsch wax.Polymethylene wax,Examples thereof include amide waxes, higher fatty acids, long chain alcohols, ester waxes and derivatives thereof such as graft compounds and block compounds, and those having a sharp maximum endothermic peak in the DSC endothermic curve from which these low molecular weight components have been removed are preferred.
[0096]
Preferred examples of the wax include linear alkyl alcohols having 10 to 100 carbon atoms, linear fatty acids, linear acid amides, linear esters, and montan derivatives. Those from which impurities such as liquid fatty acids have been previously removed from these waxes are also preferred. More preferably, the wax used is a low molecular weight alkylene polymer obtained by polymerizing alkylene by radical polymerization under high pressure or by using a Ziegler catalyst or other catalyst under low pressure; a low molecular weight alkylene polymer by-produced when polymerizing alkylene. Separation and purification: Extract specific components from a hydrocarbon polymer distillation residue obtained by the age method from synthesis gas consisting of carbon monoxide and hydrogen, or from a synthetic hydrocarbon obtained by hydrogenating the distillation residue Examples include fractionated polymethylene wax. These waxes may contain an antioxidant. The ester wax used in the present invention is formed from compounds represented by the following general formulas (11) to (15) and has a melting point of 40 to 100 ° C.
[0097]
Embedded image

(Wherein, a and b are integers of 0 to 4, and a + b is 4. R^FiveAnd R⁶Is an organic group having 1 to 40 carbon atoms, R^FiveAnd R⁶And the carbon number difference is 3 or more. m and n are integers of 0 to 25, and m and n are not 0 at the same time. )
[0098]
Embedded image

(In the formula, c and d are integers of 0 to 3, and c + d is 1 to 3. R⁸And R⁹Is an organic group having 1 to 40 carbon atoms, R⁸And R⁹And the carbon number difference is 3 or more. R⁷Is a hydrogen atom or an organic group having 1 or more carbon atoms. However, when c + d = 2, R⁷One of these is an organic group having 1 or more carbon atoms. k is an integer of 1 to 3. m and n are integers of 0 to 25, and m and n are not 0 at the same time. )
[0099]
Embedded image

(Wherein R^TenAnd R¹²Is an organic group having 6 to 32 carbon atoms, R^TenAnd R¹²May or may not be the same. R¹¹Represents an organic group having 1 to 20 carbon atoms. )
[0100]
Embedded image

(Wherein R¹³And R¹⁴Is an organic group having 6 to 32 carbon atoms, R¹³And R¹⁵May or may not be the same.
R¹⁴Is -CH₂CH₂OC₆H_FourOCH₂CH₂−,

Or-(CH₂)_f-. e represents an integer of 1 to 10, and f represents an integer of 1 to 20. )
[0101]
Embedded image

(In the formula, g is an integer of 0 to 4, h is an integer of 1 to 4, and g + h is 4. R¹⁶Is an organic group having 1 to 40 carbon atoms. m and n are integers of 0 to 25, and m and n are not 0 at the same time. )
As an ester wax as a mold release agent comprising an ester compound, the following mold release agents No. 1-No. Twelve are illustrated.
[0102]
Embedded image

When the release agent is an ester wax having an ester compound having the above structural formula, it exhibits good transparency, and when it is contained in developer particles, it exhibits good fixability.
[0103]
When using the polymerizable monomer composition to produce developer particles directly in an aqueous medium, the release agent is 1 to 40 parts by weight with respect to 100 parts by weight of the polymerizable monomer, More preferably, 3 to 30 parts by mass are blended and contained in the developer particles.
[0104]
Compared with the dry developer manufacturing method, in the developer manufacturing method by the polymerization method compared to the dry developer manufacturing method by the melt-kneading pulverization method, it is easy to encapsulate a larger amount of the release agent in the polar resin inside the developer particles. In general, a large amount of release agent can be used, which is effective for preventing the offset at the time of fixing. When the addition amount of the release agent is less than the lower limit, the effect of preventing offset is likely to be lowered, and when the upper limit is exceeded, the anti-blocking effect is lowered, and the anti-offset effect is liable to be adversely affected. The developer is likely to fuse with the developing sleeve. When the developer particles are produced by the polymerization method, developer particles having a wide particle size distribution tend to be produced.
[0105]
As the colorant, known ones can be used. For example, carbon black, iron black, C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Dyes such as basic green 6, yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, tartrazine lake, molybdenum orange, permanent orange GTR, benzidine orange G, cadmium red , Permanent Red 4R, Watching Red Calcium Salt, Brilliant Carmine 3B, Fast Violet B, Methyl Violet Lake, Bitumen, Cobalt Blue, Alkaline Blue Lake, Victoria Blue Lake, Quinacridone, Rhodamine Lake, Phthalocyanine Blue, Fast Sky Blue, Pigment Green B , Pigments such as Malachite Green Lake and Final Yellow Green G.
[0106]
  When a developer is obtained using a polymerization method, it is necessary to pay attention to the polymerization inhibitory property and water phase transferability of the colorant, and it is preferable to modify the surface. For example, it is better to perform a hydrophobic treatment with a substance that does not inhibit polymerization. In particular, dyes and carbon blacks have many polymerization inhibiting properties, so care must be taken when using them. As a preferable method for surface-treating the dye system, a method in which a polymerizable monomer is polymerized in the presence of these dyes in advance is exemplified, and the obtained colored polymer is obtained.Polymerizable monomer compositionAdd to.
[0107]
In addition to carbon black, the carbon black may be grafted with a substance that reacts with the surface functional groups of the carbon black, such as polyorganosiloxane. The colorant is added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin. When a magnetic material is used as the black colorant, 30 to 200 parts by mass are added to 100 parts by mass of the binder resin, unlike other colorants.
[0108]
Additives other than those described above for the purpose of imparting various properties in the developer are preferably 1/5 or less of the volume average particle diameter of the developer particles from the viewpoint of durability. The particle size of the additive means the average particle size obtained by observing the surface of the developer particles with an electron microscope. As additives for the purpose of imparting these properties, for example, fluidity imparting agents, abrasives, lubricants, and the like are used.
[0109]
The volume average particle diameter of the developer can be measured by the following method.
[0110]
As a measuring device, a call counter TA-II type or Coulter Multisizer II (manufactured by Coulter Inc.) is used. As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTONR-II (manufactured by Coulter Scientific Japan) can be used.
[0111]
As a measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electric field aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte solution was suspended in an ultrasonic disperser for about 1 to 3 minutes while the sample was suspended, and the volume and number distribution of the developer were measured by measuring the volume and number of the developer using the 100 μm aperture as the aperture. And calculate. The volume average particle diameter is calculated from the measured volume distribution. In measurement, the median value of each channel is used as a representative value for each channel.
[0112]
Examples of the fluidity imparting agent include carbon black and carbon fluoride. Those subjected to hydrophobic treatment are more preferred. Examples of the abrasive include nitrides (such as silicon nitride), carbides (such as silicon carbide), and metal salts (such as calcium sulfate, barium sulfate, and calcium carbonate). Examples of the lubricant include fluorine-based resin powder (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.) and the like.
[0113]
These additives are used in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the developer particles. These additives may be used alone or in combination.
[0114]
Further, when a developer is used as a magnetic developer, a magnetic substance is included in the developer. As such a magnetic substance, a substance that is magnetized in a magnetic field is used. .
[0115]
Examples of the magnetic material include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. Among them, those containing iron oxide as a main component such as triiron tetroxide and γ-iron oxide are preferable. Further, from the viewpoint of developer chargeability control, other metal elements such as silicon element or aluminum element may be contained. These magnetic materials preferably have a BET specific surface area of 2 to 3 m by a nitrogen adsorption method.²/ G, especially 3 to 28m²/ G, and a magnetic material having a Mohs hardness of 5 to 7 is preferred.
[0116]
The shape of the magnetic material includes octahedron, hexahedron, spherical shape, needle shape, scale shape, etc., but octahedron, hexahedron, sphere, and amorphous type with less anisotropy increase the image density. preferable. The number average particle diameter of the magnetic material is preferably 0.05 to 1.0 μm, more preferably 0.1 to 0.6 μm, and further preferably 0.1 to 0.4 μm.
[0117]
The amount of the magnetic material is 30 to 200 parts by mass, preferably 40 to 200 parts by mass, and more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the binder resin. If it is less than 30 parts by mass, in a developing device that uses magnetic force for developer conveyance, the transferability is insufficient, and the developer layer on the developer carrying member tends to be uneven, resulting in image unevenness. There is a tendency for the image density to decrease due to the increase. On the other hand, when the amount exceeds 200 parts by mass, there is a tendency that a problem occurs in fixability.
[0118]
In the present invention, it is preferable to add a charge control agent to the material for the purpose of controlling the chargeability of the developer. As these charge control agents, it is preferable to use those which are hardly known to have polymerization inhibition and aqueous phase transfer properties. For example, as the positive charge control agent, nigrosine dyes, triphenylmethane dyes, quaternary dyes are used. Examples of the negative charge control agent include metal-containing salicylic acid compounds, metal-containing monoazo dye compounds, styrene-acrylic acid copolymers, and styrene-methacrylic acid copolymers. Can be mentioned.
<3> Development method, development apparatus and image forming apparatus of the present invention
The developing method of the present invention is a method using the developer carrier as described above, and the developing device and the image forming apparatus of the present invention are devices incorporating the developer carrier as described above. Although it demonstrates in detail using figures, this invention is not limited to these.
[0119]
  FIG. 1 is a schematic view of an embodiment of the developing device of the present invention when a magnetic one-component developer is used. In FIG. 1, an electrophotographic photosensitive drum 1 that is an image carrier that holds an electrostatic latent image formed by a known process is rotated in the direction of arrow B. As a developer carrierDevelopment sleeve8 is a development in which the developing sleeve 8 and the photosensitive drum 1 face each other by carrying the magnetic one-component developer 4 supplied by a hopper 3 as a developer container and rotating in the direction of arrow A. The developer 4 is conveyed to the area D. In the developing sleeve 8, a magnet roller 5 in which a magnet is inscribed is disposed in order to magnetically attract and hold the developer 4 on the developing sleeve 8.
[0120]
The developing sleeve 8 used in the developing device of the present invention has a conductive resin coating layer 7 coated on a metal cylindrical tube 6 as a base. In the hopper 3, a stirring blade 10 for stirring the developer 4 is provided. Reference numeral 11 denotes a gap indicating that the developing sleeve 8 and the magnet roller 5 are in a non-contact state.
[0121]
The developer 4 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1 by friction between the developers and the conductive resin coating layer 7 on the developing sleeve 8. In the example of FIG. 1, in order to regulate the layer thickness of the developer 4 transported to the development area D, a ferromagnetic metal magnetic regulating member 2 as a developer layer thickness regulating member is provided from the surface of the developing sleeve 8. It is suspended from the hopper 3 so as to have a gap width of about 50 to 500 μm. A magnetic force line from the magnetic pole N 1 of the magnet roller 5 concentrates on the magnetic restriction member 2, whereby a thin layer of the developer 4 is formed on the developing sleeve 8. In the present invention, a nonmagnetic member can be used instead of the magnetic regulating member 2.
Due to the developer layer thickness regulating member, the thickness of the thin layer of the developer 4 formed on the developing sleeve 8 is further thinner than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing region D. Like that.
[0122]
The developer carrying member of the present invention is particularly effective when incorporated in a developing device that develops an electrostatic latent image with a thin layer of developer as described above, that is, a non-contact developing device. In D, the developer carrier of the present invention can be applied to a developing device in which the thickness of the developer layer is equal to or greater than the minimum gap between the developing sleeve 8 and the photosensitive drum 1, that is, a contact type developing device. .
[0123]
In order to avoid complicated explanation, a non-contact type developing apparatus will be described below as an example.
[0124]
A developing bias voltage is applied to the developing sleeve 8 by a developing bias power source 9 as a biasing means in order to cause the magnetic one-component developer 4 carried on the developing sleeve 8 to fly. When a DC voltage is used as the developing bias voltage, a voltage having a value between the potential of the image portion of the electrostatic latent image (the region visualized with the developer 4 attached) and the potential of the background portion is developed. 8 is preferably applied.
[0125]
In order to increase the density of the developed image or to improve the gradation, an alternating bias voltage may be applied to the developing sleeve 8 to form an oscillating electric field whose direction is alternately reversed in the developing region D. . In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage in which a DC voltage component having an intermediate value between the potential of the developed image portion and the potential of the background portion is superimposed.
[0126]
In the case of so-called regular development, a developer charged with a polarity opposite to that of the electrostatic latent image is visualized by attaching a developer to the high potential portion of the electrostatic latent image having a high potential portion and a low potential portion. Is used.
[0127]
In the so-called reversal development, a developer charged with the same polarity as the polarity of the electrostatic latent image is visualized by attaching the developer to the low potential portion of the electrostatic latent image having a high potential portion and a low potential portion. Is used.
[0128]
High potential and low potential are expressions based on absolute values. In any of these cases, the developer 4 is charged at least by friction with the developing sleeve 8.
[0129]
FIG. 2 is a schematic configuration diagram showing another embodiment of the developing device of the present invention, and FIG. 3 is a schematic configuration diagram showing still another embodiment of the developing device of the present invention.
[0130]
2 and 3, the developer layer thickness regulating members 12 and 12 'for regulating the layer thickness of the developer 4 on the developing sleeve 8 are materials having rubber elasticity such as urethane rubber and silicone rubber. Alternatively, a developer layer thickness regulating member made of an elastic plate made of a material having metal elasticity such as phosphor bronze or stainless steel is used. In the developing device shown in FIG. 2, the developer layer thickness regulating member 12 is pressed against the developing sleeve 8 in the direction opposite to the rotation direction. In the developing device shown in FIG. 3, the developer layer thickness regulating member 12 ′ is developed. It is characterized in that the sleeve 8 is pressed in the forward direction and the rotational direction.
[0131]
  In these developing devices, the developer layer thickness regulating member 12 is provided to the developing sleeve 8 via the developer layer.OrSince a thin layer of developer is formed on the developing sleeve by elastically pressing 12 ′, a thinner developer layer is formed on the developing sleeve 8 than in the case of the above-mentioned reference example of FIG. can do. The contact pressure of the developer layer thickness regulating members 12 and 12 ′ with respect to the developing sleeve 8 is a linear pressure of 5 to 50 g / cm to stabilize the developer regulation and to make the developer layer thickness suitable. It is preferable at the point which can do. When the contact pressure of the developer layer thickness regulating member is less than the linear pressure of 5 g / cm, the regulation of the developer becomes weak, causing fog and developer leakage, and when the linear pressure exceeds 50 g / cm. The damage to the developer is increased, and the developer is likely to be deteriorated and fused to the sleeve and the blade.
[0132]
2 and 3 is the same as that of the developing device shown in FIG. 1 to 3 merely schematically illustrate the developing device of the present invention, and it goes without saying that there are various forms in the shape of the developer container (hopper 3), the presence or absence of the stirring blade 10, and the arrangement of the magnetic poles. .
[0133]
  FIG. 4 is a schematic diagram of a developing device according to an embodiment of the present invention when a nonmagnetic developer is used. Unlike the developing device of FIG. 1, the developing device of FIG. 4 uses a non-magnetic developer 13 as a developing sleeve in which a conductive resin coating layer 7 is provided on the surface of a metal rod 14, Therefore, no magnet is provided. The nonmagnetic developer 13 in the hopper 3 is separated by the developer layer thickness regulating member 12.DeveloperThe layer thickness is regulated, and is further carried on the surface of the developing sleeve by being frictionally charged by friction with the developer layer thickness regulating member 12 or the conductive coating layer 7 of the developing sleeve, and is conveyed to the developing region by the developing sleeve. The
[0134]
In FIG. 5, the developer layer thickness regulating member 12 of the type shown in FIG. 2 described above is used. As the developing sleeve, a hollow metal cylindrical tube 15 provided with a conductive resin coating layer 7 is used. In the developing device shown in FIG. 5, a magnet is provided in the developing sleeve. Not. Also, a developer supply stripping member 16 is installed in the hopper 3 for stripping off the developer that has not been transferred to the photosensitive drum in the developing region from the developing sleeve and newly supplying the developer. Yes.
[0135]
As the supply stripping member 16, for example, a roller member such as resin, rubber, or sponge, a belt member, a brush member, or the like is used. By providing such a supply stripping member 16, the developer that has not been transferred to the photosensitive drum 1 is temporarily removed from the surface of the developing sleeve, so that an immobile developer that may be generated on the developing sleeve is removed. It works to prevent or make the developer charge uniform.
[0136]
When an elastic roller is used as the supply stripping member 16, the peripheral speed of the supply stripping roller is 100% of the peripheral speed of the developing sleeve 8 when rotating in the counter direction (arrow X direction) with respect to the movement of the developing sleeve. Thus, it is preferably 20 to 120%, more preferably 30 to 100%. When the peripheral speed of the supply peeling roller 16 is less than 20%, the supply of the developer is insufficient, the followability of the solid image is deteriorated, which causes a ghost image. The supply amount is increased, causing fogging due to poor regulation of the developer layer thickness and insufficient charge amount. Further, since the developer is easily damaged, fogging due to developer deterioration and developer fusion are likely to occur. When the rotation direction of the supply peeling roller is the same (forward) direction as the surface of the developing sleeve, the peripheral speed is preferably 100 to 300%, more preferably 101 to 200% with respect to the sleeve peripheral speed. However, the above-mentioned developer supply amount is sufficient. The rotation direction of the supply peeling roller is more preferably rotated in the counter direction with respect to the surface of the developing sleeve from the viewpoint of the peeling property and the supply property.
[0137]
The penetration amount of the supply stripping member 16 with respect to the developing sleeve 8 is preferably 0.5 to 2.5 mm from the viewpoint of supplying and stripping the developer. When the amount of penetration of the supply stripping member is less than 0.5 mm, ghosting is likely to occur due to insufficient stripping, and when the amount of penetration exceeds 2.5 mm, the developer damage increases and development It tends to cause fusion and fogging due to deterioration of the agent.
[0138]
The developing device as shown in FIGS. 1 to 5 which forms the toner layer on the developing sleeve as described above can be used for both a magnetic developer and a non-magnetic developer.
[0139]
Next, an example of an image forming apparatus using the developing device of the present invention illustrated in FIG. 3 will be described with reference to FIG.
[0140]
First, the surface of the photosensitive drum 1 as an image carrier is negatively charged by contact (roller) charging means 17 as primary charging means, and the digital latent image is transferred onto the photosensitive drum 1 by image scanning by laser light exposure 18. Formed. Next, the above-mentioned digital latent image is negatively charged in the hopper 3 as a developing container by a developing device having a developer layer thickness regulating member 12 ′ and provided with a developing sleeve 8 as a developer carrying member. Reversal development is performed by the sex one-component developer 4. As shown in FIG. 6, in the development area D, the conductive substrate of the photosensitive drum 1 is grounded. An alternating bias voltage, an oscillating electric field, and / or a DC voltage is applied to the developing sleeve 8 by a bias applying means 9.
[0141]
Next, when the recording material P is conveyed and arrives at the transfer portion, the contact (roller) transfer means 19 as a transfer means charges the back surface of the recording material P (the surface opposite to the photosensitive drum side) by the voltage application means 20. As a result, the developed image formed on the surface of the photosensitive drum 1 is transferred onto the recording material P by the contact transfer means 19. Next, the recording material P separated from the photosensitive drum 1 is conveyed to a heat and pressure roller fixing device 21 as a fixing unit, and a fixing process of the developed image on the recording material P is performed by the fixing device.
[0142]
The one-component developer 4 remaining on the photosensitive drum 1 after the transfer process is removed by a cleaning unit 23 having a cleaning blade 22. When the remaining one-component developer 4 is small, the cleaning step can be omitted. The photosensitive drum 1 after cleaning is neutralized by erase exposure 24 as necessary, and the above process starting from the charging process by the contact (roller) charging unit 17 as the primary charging unit is repeated again.
[0143]
The photosensitive drum (that is, the image carrier) 1 has a photosensitive layer and a conductive substrate, and moves in the direction of arrow B. The developing sleeve 8 rotates so as to proceed in the same direction (arrow A direction) as the surface of the photosensitive drum 1 in the developing region D. The one-component developer 4 in the hopper 3 is carried on the developing sleeve 8 and is given, for example, negative triboelectric charge by friction with the surface of the developing sleeve 8 and / or friction between the developers. Further, the developer regulation regulating member 12 ′ regulates the thickness of the developer layer to be thin (30 μm to 300 μm) and uniformly, so that the developer is thinner than the gap between the photosensitive drum 1 and the development sleeve 8 in the development region D. A layer is formed. By adjusting the rotation speed of the developing sleeve 8, the surface speed of the developing sleeve 8 is made substantially equal to or close to the speed of the surface of the photosensitive drum 1.
[0144]
In the developing region D, an alternating bias voltage or an oscillating electric field may be applied to the developing sleeve 8 by the bias applying unit 9 as a developing bias voltage. The alternating bias voltage may be such that f is 200 to 4,000 Hz and Vpp is 500 to 3,000 V. When the developer is transferred in the development region D, the developer is transferred to the electrostatic latent image side due to the electrostatic force on the surface of the photosensitive drum 1 and the action of the developing bias voltage such as an alternating bias voltage or an oscillating electric field.
[0145]
As the primary charging unit, the charging roller 17 is used as the contact charging unit. However, a contact charging unit such as a charging blade or a charging brush may be used, and a non-contact corona charging unit may be used. However, the contact charging means is preferable in that ozone generation due to charging is small.
[0146]
As the transfer unit, the contact transfer unit such as the transfer roller 19 has been described above, but a non-contact corona transfer unit may be used. However, the contact transfer means is also preferable in that it generates less ozone due to transfer.
[0147]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to these examples. In addition, all the parts in the following mixing | blending are a mass part.
[0148]
[Example 1]
<Manufacture of magnetic developer 1>
To 500 parts by mass of ion-exchanged water in the reaction vessel, 0.1M Na_ThreePO_FourAfter charging 320 parts by mass of the aqueous solution and heating to 60 ° C., 1M-CaCl₂Gradually add 47 parts by weight of aqueous solution and add Ca._Three(PO_Four)₂An aqueous medium containing was obtained.
[0149]
The following materials were uniformly dispersed and mixed using an attritor.
・ 80 parts by mass of styrene
・ 20 parts by mass of n-butyl acrylate
・ Unsaturated polyester resin 2 parts by mass
・ 3 parts by weight of saturated polyester resin
-Monoazo dye-based Fe compound 1 part by mass
・ 90 parts by mass of hydrophobized magnetic material
This monomer composition was heated to 60 ° C., and 6 parts by mass of ester wax (maximum endothermic peak 72 ° C. in DSC) was added and dissolved therein, and then the polymerization initiator 2,2′-azobis ( 2,5 parts by mass of 2,4-dimethylvaleronitrile) was dissolved. The polymerizable monomer composition is charged into the aqueous medium, 60 ° C., N₂Under purge, the mixture was stirred for 15 minutes at 10,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) and granulated. Then, it was made to react at 60 degreeC for 6 hours, stirring with a paddle stirring blade. Thereafter, the liquid temperature was set to 80 ° C., and stirring was further continued for 4 hours. After completion of the reaction, distillation is further performed at 80 ° C. for 2 hours, after which the suspension is cooled, hydrochloric acid is added and Ca is added._Three(PO_Four)₂Was dissolved, filtered, washed with water, and dried to obtain developer particles. A magnetic developer 1 was obtained by mixing 100 parts by mass of the developer particles with 1.2 parts by mass of hydrophobic silica treated with hexamethyldisilazane using a Henschel mixer (Mitsui Miike Chemical Co., Ltd.). Table 1 shows the physical properties of the developer.
[0150]
[Table 1]

<Manufacture of developer carrier 1>
Next, the production of the development carrier will be described.
[0151]
First, the triboelectric charge amount with the iron powder of the quaternary ammonium salt compound represented by the above formula (3) is determined by a blow-off method using a commercially available triboelectric charge measuring device (TB-200 type manufactured by Toshiba Chemical). As a result, it was positive polarity.
[0152]
  In addition, conductive spherical carbon particles A were used as the conductive spherical particles. The physical properties are shown in Table 2. Number average particle diameter 5.0 μm, true density 1.50 g / cm³, Volume resistancevalue7.5 × 10^-2The ratio of Ω · cm and major axis / minor axis was 1.15.
[0153]
[Table 2]

The following materials were dispersed with zirconia particles having a diameter of 2 mm using a sand mill for 3 hours.
・ 10 parts by mass of carbon
・ 90 parts by mass of graphite
・ Manufactured using ammonia as a catalyst
500 parts by mass of phenol resin intermediate (solid content 50%)
・ 40 parts by mass of quaternary ammonium salt compound
・ 40 parts by mass of the spherical carbon particles A
・ 130 parts by mass of methanol
Thereafter, the zirconia particles were separated with a sieve, and the solid content was adjusted to 32% with methanol to obtain a paint 1. This paint is formed by spraying a coating of about 12 μm on an aluminum cylinder having a diameter of 24.5 mm, and then heated and cured by a hot air dryer at 150 ° C. for 30 minutes to provide a developer carrier 1 having a resin coating layer. Was made. Table 3 shows the paint formulation and the physical properties of the developer carrier.
[0154]
[Table 3]

This developer carrier was incorporated into NP6350 (Canon copier), and imaged using the above developer, and evaluated. The results are shown in Tables 4 and 5.
<Image output evaluation method>
Durability tests were conducted and evaluated for the evaluation items listed below.
(1) Image density
The image was printed at 100 ° C for NP6350 in a low temperature (N / L) environment at 24 ° C and 10% RH, and a high temperature and high humidity (H / H) environment of 30 ° C and 80% RH. The number of creative processors 660 was up to 17,000 (17k). The image density of a black circle with a diameter of 5 mm on a test chart with an image ratio of 5.5% was measured with a reflection density RD918 (manufactured by Macbeth), and an average value of five points was taken as the image density.
(2) Developer charge amount (Q / M) and developer transport amount (M / S)
The developer carried on the developer carrying member is sucked and collected by a metal cylindrical tube and a cylindrical filter. At that time, the charge amount Q stored in the condenser through the metal cylindrical tube, the collected developer weight M, and development From the area S where the agent is sucked, the charge amount per unit weight Q / M (mC / kg) and the developer weight per unit weight M / S (mg / cm²) Were calculated, respectively, as the developer charge amount (Q / M) and the developer transport amount (M / S).
(3) Streaks, unevenness
Check various images such as solid black, halftone, and line images, referring to the visual observation of developer coat defects on the developer carrier such as streaks and wavy unevenness on the developer carrier. The evaluation results are shown by the following indices.
A: Neither the image nor the developer carrier can be confirmed at all.
○: Slightly confirmed on the developer carrying member, but hardly confirmed on the image.
○ △: About one to several tens of images can be confirmed by looking through the image.
Δ: First halftone image or solid black image can be confirmed on the first round of the developer carrier cycle.
(Triangle | delta): It can confirm with a halftone image or a solid black image. Practical level lower limit.
Δ: Image defect can be confirmed in the entire solid black image. Unusable level.
X: It can confirm also on a solid white image.
(4) Blotch
Confirm various images such as solid black, halftone, etc., in that case, referring to the visual observation of the developer coat failure on the developer carrier such as a blotch on the developer carrier, the evaluation results are as follows: Indicated by indicators.
A: Neither the image nor the developer carrier can be confirmed at all.
○: Slightly confirmed on the developer carrying member, but hardly confirmed on the image.
○ △: About one to several tens of images can be confirmed by looking through the image.
Δ: First halftone image or solid black image can be confirmed on the first round of the developer carrier cycle.
(Triangle | delta): It can confirm with a halftone image or a solid black image. Practical level lower limit.
Δ: Image defect can be confirmed in the entire solid black image. Unusable level.
X: It can confirm also on a solid white image.
(5) Ghost
The position of the developer carrying member that developed the image in which the solid white portion and the solid black portion are adjacent comes to the developing position at the next rotation of the developer carrying member, and the halftone image is developed so that the halftone image is developed. The appearing shade difference was visually evaluated according to the following criteria.
○: No difference in density is observed.
○ △: A slight difference in density is observed.
Δ: A slight difference in shading is seen, but practical use is possible.
X: A difference in shading is noticeable and impractical.
(6) Contamination resistance of the resin coating layer
The surface of the developer carrying member after durability was observed with an SEM, and the degree of developer contamination was evaluated according to the following criteria.
○: Slight contamination is observed.
○ △: Some contamination is observed.
Δ: Contamination is partially observed.
X: Significant contamination is observed.
(7) Abrasion amount of conductive resin coating layer (film scraping)
A laser dimension measuring device manufactured by KEYENCE was used. Using the controller LS-5500 and sensor head LS-5040T, the sensor unit is separately fixed to an apparatus equipped with a developer carrier fixing jig and a developer carrier feed mechanism, and the average value of the outer diameter dimensions of the developer carrier Measurements were made from The measurement was divided into 30 parts in the longitudinal direction of the developer carrying member, 30 points were measured, and a total of 60 points were measured, and the average value was taken. Measure the outer diameter of the developer carrier before applying the resin coating layer on the surface in advance, measure the outer diameter after forming the resin coating layer on the surface, and further measure the outer diameter after durable use. And the amount of scraping.
(8) Transfer rate
As an evaluation method, the toner amount on the drum latent image and on the paper before and after the endurance was measured, and the transfer rate was calculated from the ratio. Also, transferability maintenance was calculated from the ratio of transfer rate before and after endurance. The evaluation index was as follows.
○: Maintaining a transfer maintenance rate of 90% or more before and after endurance
Δ: Transfer retention decreased to 80-90% before and after endurance
X: The transfer maintenance rate decreased to 80% or less before and after durability.
[0155]
[Table 4]

[0156]
[Table 5]

[0157]
[Example 2]
When the charge amount of the quaternary ammonium salt compound represented by the above formula (4) was measured by the blow-off method using iron powder in the same manner as in Example 1, it was positive. A coating material was prepared in the same manner as in Example 1 except that the quaternary ammonium salt compound represented by the above formula (4) was used, and a developer carrier 2 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0158]
[Example 3]
When the charge amount of the quaternary ammonium salt compound represented by the above formula (5) was measured by the blow-off method using iron powder in the same manner as in Example 1, it was positive. A coating material was prepared in the same manner as in Example 1 except that the quaternary ammonium salt compound represented by the above formula (5) was used, and a developer carrier 3 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0159]
[Example 4]
In Example 1, a developer was prepared in the same manner as in Example 1 except that the amount of addition of the quaternary ammonium salt compound represented by the above formula (3) was changed from 40 parts by mass to 10 parts by mass. A support 4 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0160]
[Example 5]
In Example 1, a developer was prepared in the same manner as in Example 1 except that the amount of addition of the quaternary ammonium salt compound represented by the above formula (3) was changed from 40 parts by mass to 60 parts by mass. A support 5 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0161]
[Example 6]
In Example 5, the developer carrying member except that the quaternary ammonium salt compound represented by the above formula (3) was changed to the quaternary ammonium salt compound represented by the above formula (4) to prepare a coating material. 6 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0162]
[Example 7]
In Example 4, the developer carrying member except that the quaternary ammonium salt compound represented by the above formula (3) was replaced with the quaternary ammonium salt compound represented by the above formula (4) to prepare a coating material. 7 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0163]
[Example 8]
Example 1 except that PMMA (polymethyl methacrylate) particles B having a number average particle diameter of 5.1 μm were used instead of the spherical carbon particles A having a number average particle diameter of 5.0 μm used in Example 1. Similarly, developer carrier 8 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0164]
  This PMMA particle B has a true density of 1.19 g / cm.³, Volume resistancevalue10¹⁵The ratio of major axis / minor axis was 1.12.
[0165]
[Example 9]
In the production of the developer carrier of Example 1, a paint was prepared according to the following formulation using boron nitride instead of graphite used for the resin coating layer, and a developer carrier 9 was obtained in the same manner as in Example 1. It was. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
・ 10 parts by mass of carbon
・ 90 parts by mass of boron nitride
・ Manufactured using ammonia as a catalyst
500 parts by mass of phenol resin intermediate (solid content 50%)
・ 40 parts by mass of quaternary ammonium salt compound
・ 40 parts by mass of the spherical carbon particles A
・ Methanol 150 parts by mass
[0166]
[Example 10]
In the production of the developer carrier of Example 1, a paint was prepared according to the following formulation using molybdenum disulfide instead of graphite used for the resin coating layer, and the developer carrier 10 was obtained in the same manner as in Example 1. It was. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
・ 10 parts by mass of carbon
・ 100 parts by mass of molybdenum disulfide
・ Manufactured using ammonia as a catalyst
500 parts by mass of phenol resin intermediate (solid content 50%)
・ 40 parts by mass of quaternary ammonium salt compound (Formula 3)
・ 40 parts by mass of the spherical carbon particles A
・ 170 parts by mass of methanol
[0167]
Example 11
In the production of the developer carrier of Example 1, a coating material used for the resin coating layer was prepared according to the following formulation, and a developer carrier 11 was obtained in the same manner as in Example 1. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
-833 parts by mass based on 66 nylon
Nylon copolymer
・ 10 parts by mass of carbon
・ 90 parts by mass of graphite
・ 40 parts by mass of quaternary ammonium salt compound (Formula 3)
・ 40 parts by mass of the spherical carbon particles A
・ 130 parts by mass of methanol
[0168]
Example 12
In the production of the developer carrier of Example 1, a paint used for the resin coating layer was prepared according to the following formulation, and a developer carrier 12 was obtained in the same manner as in Example 1. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
-625 parts by mass of urethane resin (solid content 40%)
・ 10 parts by mass of carbon
・ 90 parts by mass of graphite
・ 40 parts by mass of quaternary ammonium salt compound (Formula 3)
・ 40 parts by mass of the spherical carbon particles A
・ 130 parts by mass of methanol
[0169]
Example 13
In the production of the developer carrier of Example 1, a paint used for the resin coating layer was prepared according to the following formulation, and a developer carrier 13 was obtained in the same manner as in Example 1. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
・ 10 parts by mass of carbon
・ 90 parts by mass of graphite
・ Manufactured using ammonia as a catalyst
500 parts by mass of phenol resin intermediate (solid content 50%)
・ 40 parts by mass of quaternary ammonium salt compound (Formula 3)
・ Methanol 100 parts by mass
[0170]
  The following materials were dispersed in the same manner as in Example 1, and the IPWith A (isopropyl alcohol)The solid content was adjusted to 31% to obtain a paint.
・ 10 parts by mass of carbon
・ 90 parts by mass of graphite
・ Manufactured using ammonia as a catalyst
  500 parts by mass of phenol resin intermediate (solid content 50%)
・ Spherical carbon particle A 40 parts by mass
・ IPA 100 parts by mass
  A developing carrier 14 was produced from this paint in the same manner as in Example 1, and image formation was evaluated in the same manner as in Example 1. Table 3 shows the paint formulation and the physical properties of the developer carrier. In addition, Table 4 and Table 5 show the image output evaluation results.
[0171]
[Comparative Example 2]
In Example 1, the developer carrying member except that the quaternary ammonium salt compound represented by the above formula (3) was changed to the quaternary ammonium salt compound represented by the above formula (2) to prepare a coating material. 15 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. This was evaluated in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0172]
In addition, about the quaternary ammonium salt compound represented by the said Formula (2), when the charge amount was measured by the blow-off using iron powder similarly to Example 1, the negative polarity was shown.
[0173]
[Comparative Example 3]
When the triboelectric charge amount with the iron powder of the chromium complex of azonaphthol containing chlorophenol was determined by the blow-off method in the same manner as in Example 1, it was negative. In Example 1, in place of the quaternary ammonium salt compound represented by the above formula (3), an azonaphthol chromium complex containing chlorophenol was used in the same manner as in Example 1 except that the developer carrying member ( 16) was prepared, and image output evaluation was performed in the same manner as in Example 1. Table 3 shows the paint formulation and the physical properties of the developer carrier. Table 4 and Table 5 show the image evaluation results.
[0174]
Examples 14 to 16
<Manufacture of magnetic developer 2>
Magnetic developer 2 was obtained in the same manner except that 90 parts by mass of a magnetic material that had not been subjected to a hydrophobic treatment was used in place of the hydrophobized magnetic material in the production of magnetic developer 1. Table 1 shows the physical properties of Magnetic Developer 2.
[0175]
Using the magnetic developer 2 obtained above for the developer carriers 1 to 3 prepared in Examples 1 to 3, image evaluation was performed in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0176]
[Comparative Example 4]
Developer carrier used in Comparative Example 114And the magnetic developer 2 were used to evaluate image output in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0177]
[Comparative Example 5]
Developer carrier used in Comparative Example 215And the magnetic developer 2 were used to evaluate image output in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0178]
[Examples 17-19]
<Manufacture of magnetic developer 3> In the manufacture of magnetic developer 2, after granulation with a TK homomixer, after stirring with a paddle stirring blade at 65 ° C. for 6 hours, the temperature was raised to 80 ° C. and then suspended. The liquid was stirred with an attritor (Mitsui Miike Chemical Co., Ltd.), reacted for another 4 hours, and then distilled at 80 ° C. In the same manner as in the production of the magnetic developer 1, a negatively chargeable magnetic developer 3 was obtained. Table 1 shows the physical properties of the magnetic developer 3 obtained.
[0179]
Using the magnetic developer 3 obtained above for the developer carriers 1 to 3 produced in Examples 1 to 3, image evaluation was performed in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0180]
[Comparative Examples 6 and 7]
Developer carrier used in Comparative Example 114And the magnetic developer 3 were used to evaluate image output in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0181]
[Comparative Examples 8 and 9]
<Manufacture of Magnetic Developer 4> The following materials were mixed in a blender and melt-kneaded with a biaxial extruder heated to 130 ° C.
    ・ Styrene-butyl acrylateCopolymer resin   100 parts by mass
    ・ Unsaturated polyester resin 2 parts by mass
    ・ 3 parts by weight of saturated polyester resin
    -Monoazo dye-based Fe compound 1 part by mass
    ・ 90 parts by mass of hydrophobized magnetic material
  The cooled kneaded material was coarsely pulverized with a hammer mill, and the coarsely pulverized powder was finely pulverized by a pulverizing means having an airflow classifier and a collision type airflow pulverizer. The obtained finely pulverized product is 1.96 × 10 in a multi-division classifier using the Coanda effect that incorporates a forced powder dispersion device using compressed air in the powder supply unit.^-1The magnetic developer 4 was obtained by forcibly dispersing and supplying with compressed air of MPa and classifying strictly. Table 1 shows the physical properties of the magnetic developer 4.
[0182]
The developer carrying bodies 1 and 2 produced in Examples 1 and 2 were evaluated for image formation using the magnetic developer 4 in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0183]
[Comparative Examples 10 and 11]
Developer carrier used in Comparative Example 114Or developer carrier used in Comparative Example 215And the magnetic developer 4 were used to evaluate image output in the same manner as in Example 1. The results are shown in Tables 4 and 5.
[0184]
[Example 20]
<Manufacture of Developer 5> 0.1M Na in 10000 parts by mass of ion-exchanged water in a reaction vessel_ThreePO_Four1000 parts by mass of aqueous solution and 85 parts by mass of 1M HCl aqueous solution were added, and N₂The temperature was kept at 65 ° C. for 60 minutes while purging. 1200 using TK homomixer
While stirring at 0 rpm, 10M-CaCl₂60 parts by mass of an aqueous solution was added all at once, pH 6
. 5 Ca_Three(PO_Four)₂An aqueous medium containing was prepared.
[0185]
The following materials were kept at 65 ° C. in a separate container, and uniformly dissolved and dispersed at 12000 rpm using a TK homomixer.
・ 80 parts by mass of styrene
・ 20 parts by mass of n-butyl acrylate
・ 7 parts by mass of carbon black
・ 5.5 parts by mass of polyester resin
・ 1 parts by weight of metal salicylate
・ Ester wax 15 parts by mass
・ Crosslinking agent (divinylbenzene) 0.25 parts by mass
In this, 4 parts by mass of a polymerization initiator 2,2'-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition. The polymerizable monomer composition is charged into the aqueous medium in the reaction vessel,₂Under a purge, the polymerizable monomer composition was granulated by stirring at 10,000 rpm for 10 minutes with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Then, it was made to react at 65 degreeC for 6 hours, stirring with a paddle stirring blade. Thereafter, the liquid temperature was raised to 80 ° C., and stirring was further continued for 9 hours. After completion of the reaction, distillation was performed at 85 ° C. After completion of the polymerization reaction, the suspension is cooled, hydrochloric acid is added and Ca is added._Three(PO_Four)₂Was dissolved, filtered, washed with water, and dried to obtain developer particles.
[0186]
When the cross section of the developer particles was observed by TEM, the release agent was favorably contained in the outer shell resin. To 100 parts by mass of the obtained developer particles, 1.5 parts by mass of hydrophobic titanium oxide fine powder was mixed to obtain negatively chargeable developer 5. The obtained developer had a circle-equivalent number average diameter D1 of 4.9 μm. Table 1 shows the physical properties of Developer 5.
<Manufacture of developer carrier 17>
The following materials were dispersed in the same manner as in Example 1 with zirconia particles having a diameter of 2 mm using a sand mill for 3 hours to obtain a paint.
・ Carbon 20 parts by mass
・ Graphite 80 parts by mass
・ Manufactured using ammonia as a catalyst
400 parts by mass of phenol resin intermediate (solid content 50%)
-40 parts by mass of a quaternary ammonium salt compound (formula (3))
・ Methanol 150 parts by mass
The paint is formed by spraying an approximately 11 μm film on an aluminum cylinder having a diameter of 20 mm, and then heated and cured by a hot air dryer at 150 ° C. for 30 minutes to produce a developer carrier 17 having a resin film layer. did. Table 3 shows the paint formulation and the physical properties of the developer carrier.
[0187]
This developer carrying member was incorporated into a modified machine of Creative Processor 660 (Canon Copier), and image development was evaluated using the developer 5. The results are shown in Tables 6 and 7.
[0188]
[Table 6]

[0189]
[Table 7]

[0190]
[Comparative Example 12]
<Manufacture of Developer 6> In the manufacture of Developer 6, after granulation with a TK homomixer, the mixture was stirred at 65 ° C. for 6 hours with a paddle stirring blade and then heated to 85 ° C. The mixture was stirred with an attritor (Mitsui Miike Chemical Co., Ltd.), and further reacted for 9 hours, followed by distillation at 85 ° C. In the same manner as in the production of the magnetic developer 3, 1.5 parts by mass of hydrophobic titanium oxide fine powder was mixed with 100 parts by mass of the obtained developer particles, whereby a negatively chargeable developer 6 was obtained. The obtained developer 6 had a circle-equivalent number average diameter D1 of 5.1 μm. Table 1 shows the physical properties of Developer 6.
[0191]
  Example 20Using the developer 6 obtained above, the developer carrier 17 produced in Example20The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0192]
[Example 21]
Example20In Example 1, except that the amount of addition of the quaternary ammonium salt compound represented by the above formula (3) was changed from 40 parts by mass to 60 parts by mass.20In the same manner as described above, a developer carrying member 18 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 18 and developer 520The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0193]
[Comparative Example 13]
Example using developer carrier 18 and developer 620The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0194]
[Example 22]
Example20In Example 1, except that the amount of addition of the quaternary ammonium salt compound represented by the above formula (3) was changed from 40 parts by mass to 10 parts by mass.20In the same manner, a developer carrying member 19 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 19 and developer 520The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0195]
[Comparative Example 14]
Example using developer carrier 19 and developer 620The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0196]
[Example 23]
In the production of the developer carrier of Example 1, a coating material used for the resin coating layer was prepared according to the following formulation, and a developer carrier 20 was obtained in the same manner as in Example 1. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 20 and developer 520The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
    ・ Carbon 20 parts by mass
    ・ Graphite 80 parts by mass
    ・ Manufactured using ammonia as a catalyst
      Phenolic resin intermediate (solid content 50%) 400 parts by mass
    ・ 40 parts by mass of quaternary ammonium salt compound (Formula 3)
    ・ 40 parts by mass of the spherical carbon particles A
    ・ Methanol 150 parts by mass
[0197]
[Example 24]
Example20In Example 1, except that the paint was prepared using the quaternary ammonium salt compound represented by the above formula (4) instead of the quaternary ammonium salt compound represented by the above formula (3).20In the same manner, a developer carrying member 21 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 21 and developer 520The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0198]
[Comparative Example 15]
Example20In Example 1, except that the paint was prepared using the quaternary ammonium salt compound represented by the above formula (6) instead of the quaternary ammonium salt compound represented by the above formula (3).20In the same manner as described above, a developer carrying member 22 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 22 and developer 520The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0199]
[Comparative Example 16]
Example20In Example 1, except that a coating was prepared using a chromium complex of azonaphthol containing chlorophenol used in Comparative Example 3 instead of the quaternary ammonium salt compound represented by the above formula (3).20In the same manner, a developer carrying member 23 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 23 and developer 520The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0200]
[Comparative Example 17]
In Example 20, except that the paint was prepared using the chromium complex of azonaphthol containing chlorophenol used in Comparative Example 3 instead of the quaternary ammonium salt compound represented by the above formula (3), Example20In the same manner, a developer carrying member 23 was obtained. Table 3 shows the paint formulation and the physical properties of the developer carrier. Example using developer carrier 23 and developer 5
20The image output was evaluated in the same manner as above. The results are shown in Tables 6 and 7.
[0201]
[Comparative Example 18]
Example except that a conductive resin coating layer was not formed, and a 20 mm diameter FGB sleeve blasted on the substrate surface using glass beads having a particle size of # 300 was used as the developer carrier 25.20In the same manner as described above, the image output was evaluated using the developer 5. The results are shown in Tables 6 and 7.
[0202]
【The invention's effect】
As described above, according to the present invention, the average circularity of the developer measured by the flow type particle image measuring device is 0.920 to 0.995, and the circularity standard deviation isNegatively chargeable developer of 0.045 or lessThe resin coating layer formed on the developer carrier substrate contains at least a binder resin for the coating layer and a quaternary ammonium salt compound that is positively charged with respect to iron powder.The resin coating layer is composed of at least a binder resin for the coating layer, and a part or all of the binder resin for the coating layer contains —NH ₂ Group, = NH group,
Or a binder resin for a coating layer having at least one of —NH— bonds.With this characteristic, it is possible to stably and appropriately charge the developer without overcharging (charging up) the developer, and the negatively chargeable developer can be controlled to a suitable tribo. A developing method, a developing device, and an image forming apparatus can be provided.
[0203]
Furthermore, a developing method, a developing device, and an image forming apparatus that can be controlled to a suitable tribo even when using a developer that is easily charged up and that has been difficult to impart stable charge conventionally. Can be provided.
[0204]
In addition, it is difficult to charge up the developer, and it can be stably and appropriately charged even in different environments, so it is resistant to contamination, such as preventing adhesion to the surface of the developer carrier. It is possible to provide a high-quality image that is excellent in the image quality and has no stripes, ghosts, or blotches even in the long-term image output durability.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a configuration example of a developing device of the present invention using a one-component magnetic developer.
FIG. 2 is a schematic diagram illustrating a configuration example of a developing device of the present invention using a one-component magnetic developer.
FIG. 3 is a schematic diagram illustrating a configuration example of a developing device of the present invention using a one-component magnetic developer.
FIG. 4 is a schematic diagram illustrating a configuration example of a developing device of the present invention using a one-component nonmagnetic developer.
FIG. 5 is a schematic diagram illustrating a configuration example of a developing device of the present invention using a one-component nonmagnetic developer.
FIG. 6 is a schematic diagram illustrating a configuration example of an image forming apparatus of the present invention using a one-component nonmagnetic developer.
[Explanation of symbols]
1 Electrophotographic photosensitive drum (image carrier)
2 Magnetic restriction member
3 Hopper
4 Developer
6 Metal cylindrical tube (base)
7 Conductive resin coating layer
8 Development sleeve (developer carrier)
9 Power supply
10 Stirring blade
11 gap
12 Developer layer thickness regulating member
12 'developer layer thickness regulating member
13 Non-magnetic developer
14 Metal rod
15 Metal cylindrical tube
16 Supply stripping member
17 Contact charging means
18 Exposure
19 Contact transfer means
20 Voltage application means
21 Heating and pressure roller fixing device
22 Cleaning blade
23 Cleaning means
24 Erase exposure

Claims (17)

A step of supporting the developer contained in the developer container on the developer carrier, a step of regulating the layer thickness of the developer on the developer carrier by a developer layer thickness regulating member, and the layer thickness being regulated A step of carrying and transporting the developer to a development region where the developer carrying body and the image carrying body face each other, transferring the developer on the developer carrying body to an electrostatic latent image on the image carrying body, A developing method, wherein the developer has at least a binder resin and a colorant, and an average circularity measured by a flow type particle image measuring device is 0.920 to 0.995, a negatively chargeable developer having a circularity standard deviation of 0.045 or less, and the developer carrier comprises a substrate and a resin coating layer formed on the substrate, and the resin coating The layer is a quaternary ammonia that is at least positively charged to the iron powder. It contains salt-free compound, wherein the resin coating layer comprises a binder resin for at least the coating layer, a part or all of the coating layer for the binder resin, in its molecular structure, -NH ₂ group, = NH group , Or binding for coating layer having at least either —NH— bond
A developing method comprising a resin .   The developing method according to claim 1, wherein the binder resin for the coating layer of the resin coating layer contains at least a phenol resin. The phenol resin, using a nitrogen-containing compound as a catalyst, a phenol resin produced is engaged addition and condensation of phenol and an aldehyde, -NH ₂ group in its structure, = N
The developing method according to claim 2, which is a phenol resin having either an H group or an —NH— bond.   The developing method according to claim 1, wherein the resin coating layer is a conductive coating layer in which conductive fine powder is dispersed and contained in a binder resin for a coating layer.   5. The developer has an equivalent circle number average diameter D1 of 2 to 10 μm in a number-based equivalent circle diameter-circularity scattergram measured by a flow-type particle image measuring apparatus. The developing method as described.   The developing method according to claim 1, wherein the developer has an average circularity of 0.965 to 0.990 and a circularity standard deviation of less than 0.035.   7. The developer has 15% by number or less of developer particles having a circularity of less than 0.950 in a number-based equivalent circle diameter-circularity scattergram measured by a flow particle image measuring device. The developing method according to any one of the above.   The developing method according to claim 1, wherein the developer is a developer obtained by suspension polymerization of a polymerizable monomer composition in an aqueous medium. A developer, a developer carrier that carries and transports the developer, a developer layer thickness regulating member that regulates the thickness of the developer layer on the developer carrier, and the developer whose layer thickness is regulated Means for carrying and transporting the developer carrying body and the image carrying body to the opposite developing area, and means for transferring the developer on the developer carrying body to an electrostatic latent image on the image carrying body to make a visible image And the developer has at least a binder resin and a colorant, and has an average circularity of 0.920 to 0.995 measured by a flow particle image measuring device, A negatively chargeable developer having a circularity standard deviation of 0.045 or less , wherein the developer carrier comprises a substrate and a resin coating layer formed on the substrate, and the resin coating layer comprises at least iron powder. containing quaternary ammonium salt compound which is positively chargeable respect, the tree Coating layer is made of a binder resin for at least the coating layer, a part or all of the binder resin for the coating layer, in its molecular structure, -NH ₂ group, = NH group or,
A developing device, which is a binder resin for a coating layer having at least one of —NH— bonds .   The developing device according to claim 9, wherein the binder resin for the coating layer of the resin coating layer contains at least a phenol resin. The phenol resin, using a nitrogen-containing compound as a catalyst, a phenol resin produced is engaged addition and condensation of phenol and an aldehyde, -NH ₂ group in its structure, = N
The developing device according to claim 10, which is a phenol resin having either an H group or an —NH— bond.   The developing device according to claim 9, wherein the resin coating layer is a conductive coating layer in which conductive fine powder is dispersed and contained in a binder resin for a coating layer.   13. The developer according to claim 9, wherein the developer has a circle-based number-average diameter D1 of 2 to 10 μm in a number-based circle-equivalent diameter-circularity scattergram measured by a flow type particle image measuring device. The developing device described.   The developing device according to any one of claims 9 to 13, wherein the developer has an average circularity of 0.965 to 0.990 and a circularity standard deviation of less than 0.035.   15. The developer according to claim 9, wherein the number of developer particles having a circularity of less than 0.950 is 15% by number or less in a number-based equivalent circle diameter-circularity scattergram measured by a flow particle image measuring device. The developing device according to any one of the above.   The developing device according to claim 9, wherein the developer is a developer obtained by suspension polymerization of a polymerizable monomer composition in an aqueous medium. An image carrier for carrying an electrostatic latent image, a charging means for applying a voltage to the charging member to charge the image carrier, and an electrostatic latent image for forming an electrostatic latent image on the charged image carrier. An image forming unit; a developing unit configured to transfer a developer carried on the developer carrying member to an electrostatic latent image formed on the image carrying member to form a toner image on the image carrying member; and An image forming apparatus comprising: a transfer unit that electrostatically transfers a toner image formed on a body surface to a transfer material; and a fixing unit that heats and fixes the toner image transferred onto the transfer material. An image forming apparatus comprising the developing device according to claim 9.

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