JP4006325B2 - Developer carrier, developing device, and process cartridge - Google Patents

Description

【００３７】
〔上記式（１）において、Ｒ₁、Ｒ₂、Ｒ₃、Ｒ₄、Ｒ₅、Ｒ₆は水素原子、またはメチル基等のアルキル基或いはフェニル残基等の脂肪族または芳香族炭化水素残基、メチロール基、ブチロール基等の低級アルカノール残基、またはメトキシメチル基、ブトキシメチル基等のアルコキシアルキル残基であり、夫々同一であっても異なってもかまわない。〕
【００３８】
グアナミン系樹脂は、一般に下記式（２）にて示されるグアナミンまたはその誘導体にホルムアルデヒドとの付加重合反応（脱水、脱アルコール反応）により縮合した樹脂であり、必要に応じてメタノールやブタノール等で変性してもかまわない。例として、ベンゾグアナミン樹脂、アセトグアナミン樹脂、フタログアナミン樹脂等が挙げられる。
【００３９】
【化２】

【００４０】
〔上記式（２）式において、Ｘ₁は水素原子またはメチル基等のアルキル基或いはフェニル残基等の脂肪族または芳香族炭化水素残基であり、Ｘ₂、Ｘ₃、Ｘ₄、Ｘ₅は水素原子またはメチロール基、ブチロール基等の低級アルカノール残基、またはメトキシメチル基、ブトキシメチル基等のアルコキシアルキル残基であり、夫々同一であっても異なってもかまわない。〕
【００４１】
アニリン系樹脂は、アニリンとアルデヒドとの縮合反応により得られる樹脂であり、特に本発明においては、アニリンとホルムアルデヒドとを塩酸触媒下において反応させ、酸を中和することによって得られるアニリンホルムアルデヒド樹脂を好ましく使用することができる。
【００４２】
尿素樹脂は、尿素とホルムアルデヒドを加熱させ、付加反応によりメチロール尿素、ジメチロール尿素を生成し、脱水縮合反応させることによって得られる樹脂である。本発明においては、ジメチロール尿素、ジアルコキシメチル尿素環状トリマー、アルコキシルメチル尿素環状トリマー等を特に好ましく使用することができる。
【００４３】
上記の正帯電性樹脂は、重量平均分子量（Ｍｗ）としては５００〜３，０００が好ましい。重量平均分子量（Ｍｗ）が５００より少ないと、硬化後の樹脂被覆層の機械的強度が得られず、満足した耐摩耗性が得られない場合がある。また、重量平均分子量（Ｍｗ）が３，０００を超えると、黒鉛化粒子或いはその他の成分を分散させたとき、塗料粘度が増大し、現像スリーブ上に好適な樹脂被覆層を形成することができなくなることがある。
【００４４】
上記に挙げたような正帯電性樹脂は、樹脂被覆層を構成するために必要に応じて他の樹脂と混合させて用いても良い。この樹脂としては、一般に公知の樹脂が使用可能であるが、特に主鎖もしくは側鎖末端にヒドロキシル基（水酸基）を含有する樹脂を用いた場合、上記正帯電性樹脂と架橋反応し、耐摩耗性の向上（強度アップ）や感光体汚染の防止、基体との密着性、表面層膜のひび割れ防止に有効であり、例えば、フェノール樹脂、エポキシ樹脂、ポリアミド系樹脂、ポリエステル系樹脂、ポリカーボネート系樹脂、ポリオレフィン系樹脂、シリコーン系樹脂、フッ素系樹脂、スチレン系樹脂、ビニル系樹脂、セルロース系樹脂、ポリウレタン系樹脂、ポリイミド系樹脂、アクリル系樹脂などが挙げられる。機械的強度を考慮すると硬化性の樹脂がより好ましいが、十分な機械的強度を有するものであれば、熱可塑性樹脂も適用可能である。本発明において、上記した形成材料によって現像剤担持体上に形成される樹脂被覆層は、チャージアップによる現像剤の現像剤担持体上への固着や、現像剤のチャージアップに伴って生じる現像剤担持体の表面から現像剤への帯電付与不良を防ぐためには、導電性であることが望ましい。また、樹脂被覆層の体積抵抗値としては、好ましくは１０⁴Ω・ｃｍ以下、より好ましくは１０³Ω・ｃｍ以下である。現像剤担持体表面の樹脂被覆層の体積抵抗値が１０⁴Ω・ｃｍを超えると、現像剤への帯電付与不良が発生し易く、その結果、現像剤担持体上で、所謂ブロッチの発生に伴う斑点画像や波模様画像が発生し易くなる。
【００４５】
次に、本発明の現像剤担持体において、樹脂被覆層に含有されている黒鉛化粒子について説明する。
【００４６】
本発明の現像剤担持体は、金属基体表面に有する樹脂被覆層中に、メソカーボンマイクロビーズ粒子またはバルクメソフェーズピッチ粒子を焼成して得られた黒鉛化粒子を含有していることを特徴とする。
【００４７】
該黒鉛化粒子は、従来、現像剤担持体表面の樹脂被覆層中に用いられていた、コークスなどの骨剤をタールピッチ等により固めて成形後１０００℃〜１３００℃程度で焼成してから２５００℃〜３０００℃程度で黒鉛化して得た人造黒鉛、或いは天然黒鉛からなる結晶性のグラファイトとは、該黒鉛化粒子の原材料及び製造工程が異なる。そのため、該黒鉛化粒子は従来用いていた結晶性グラファイトより黒鉛化度は若干低いものの、従来に用いられていた結晶性グラファイトと同様に高い導電性や潤滑性を有しており、さらに粒子の形状が従来に用いられていた結晶性グラファイトの燐片状或いは針状とは異なりほぼ球状であり、しかも粒子自身の硬度が比較的高いのが特徴である。従って、本発明で用いられる黒鉛化粒子は樹脂被覆層中で均一に分散しやすくなるため、均一な表面粗度と耐摩耗性を樹脂被覆層表面に与え、且つ粒子自身の形状が変化しがたいために樹脂被覆層の削れ、或いはその影響による粒子自身の脱落が生じたとしても、樹脂被覆層中から粒子が再度突出或いは露出してくることもあり、表面形状の変化を小さく抑えることができる上に、現像剤担持体表面の樹脂被覆層中に該黒鉛化粒子を用いると、トナーのチャージアップを発生させることなく、従来の結晶性グラファイトを用いた場合よりもトナーへの摩擦帯電付与能を向上することが可能となる。
【００４８】
通常、沸点が５００℃以上の有機化合物は、常圧下、不活性気相中で加熱すれば固相または液相を経由して炭素化されるが、２００℃付近までの温度で分解を始め、残留物中では環化が起こり、次いで４００℃までの間に芳香族化する。この温度を超えると、芳香族同士の重縮合が進む。中でも縮合多環芳香族やそれらの混合物であるピッチ類等のように、この温度で液状を示すものは、４００℃以上で縮合多環芳香族の平面分子からなる液晶状態をつくる。この液晶のことをメソフェーズと呼ぶ。メソフェーズは５００℃までの間でさらに高分子化が進んで層状構造を作ったまま固化する。該層状構造は、選択的な配向性の高いものであり、高温処理で黒鉛化になりやすい性質を有している。
【００４９】
本発明で用いられる黒鉛化粒子は、上記メソフェーズの状態の粒子である、メソカーボンマイクロビーズ粒子或いはバルクメソフェーズピッチ粒子を用いる。これら粒子は光学的に異方性で、しかも単一の相からなる粒子であるため、該粒子を黒鉛化してなる黒鉛化粒子においては、黒鉛化度を高め且つ球状の形状を保持させることができる。メソカーボンマイクロビーズ粒子及びバルクメソフェーズピッチ粒子の光学的異方性は、芳香族分子の積層から生じるものであり、その秩序性が黒鉛化処理でさらに発達し、高度の黒鉛化度を有する黒鉛化粒子が得られる。
【００５０】
本発明に用いられる黒鉛化粒子を得る原材料としてメソカーボンマイクロビーズ粒子を用いる場合、該メソカーボンマイクロビーズ粒子得る方法として代表的なものは、例えば、石炭系重質油または石油系重質油を３００℃〜５００℃の温度で熱処理し、重縮合させて粗メソカーボンマイクロビーズ粒子を生成し、反応生成物を濾過、静置沈降、遠心分離などの処理に供することによりメソカーボンマイクロビーズ粒子を分離した後、ベンゼン、トルエン、キシレン等の溶剤で洗浄し、さらに乾燥することによって得る方法が挙げられる。
【００５１】
また、該メソカーボンマイクロビーズ粒子を用いて黒鉛化する方法としては、まず乾燥を終えたメソカーボンマイクロビーズ粒子を、破壊させない程度の温和な力で機械的に一次分散させておくことが黒鉛化後の粒子の合一防止や均一な粒度を得るために好ましい。この一次分散を終えたメソカーボンマイクロビーズ粒子は、不活性雰囲気下において２００℃〜１５００℃の温度で一次加熱処理され、炭化される。一次加熱処理を終えた炭化物は、やはり炭化物を破壊させない程度の温和な力で炭化物を機械的に分散させることが黒鉛化後の粒子の合一防止や均一な粒度を得るために好ましい。
【００５２】
二次分散処理を終えた炭化物は、不活性雰囲気下において約２０００℃〜３５００℃で二次加熱処理することにより所望の黒鉛化粒子が得られる。
【００５３】
次に、本発明に用いられる黒鉛化粒子を得る原材料として、バルクメソフェーズピッチ粒子を用いる場合について説明する。
【００５４】
バルクメソフェーズピッチ粒子を得る方法として代表的なものは、例えば、コールタールピッチ等から溶剤分別によりβ−レジンを抽出し、これを水素添加、重質化処理を行うことによってメソフェーズピッチ粒子を得る方法、さらに、前記重質化処理後、微粉砕し、次いでベンゼンまたはトルエン等により溶剤可溶分を除去することでメソフェーズピッチ粒子を得る方法が挙げられる。本発明で用いられるバルクメソフェーズピッチ粒子はキノリン可溶分が９５質量％以上であることが好ましい。９５質量％未満のものを用いると、粒子内部が液相炭化しにくく、固相炭化するため粒子が破砕状のままとなり、球状のものが得られないことがある。
【００５５】
メソフェーズピッチ粒子を用いて黒鉛化する方法としては、先ず、前記のバルクメソフェーズピッチ粒子を２μｍ〜２５μｍに微粉砕して、これを空気中で約２００℃〜３５０℃で熱処理することにより、軽度に酸化処理する。この酸化処理によって、バルクメソフェーズピッチ粒子は表面のみ不融化され、次工程の黒鉛化熱処理時の溶融、融着が防止される。この酸化処理されたバルクメソフェーズピッチ粒子は酸素含有量が５質量％〜１５質量％であることが好ましい。５質量％未満であると熱処理時の粒子同士の融着が促進されることがあり、また１５質量％を超えると粒子内部まで酸化されてしまい、形状が破砕状のまま黒鉛化してしまい、球状のものが得られにくい場合がある。
【００５６】
次に上記の酸化処理したバルクメソフェーズピッチ粒子を窒素、アルゴン等の不活性雰囲気下にて、約２０００℃〜３５００℃で熱処理することにより所望の黒鉛化粒子が得られる。
【００５７】
上記いずれの原材料を用いた黒鉛化粒子の生成方法においても、黒鉛化粒子の焼成温度は２０００℃〜３５００℃が好ましく、２３００℃〜３２００℃がより好ましい。焼成温度が２０００℃未満の場合は、黒鉛化粒子の黒鉛化度が不十分であり、導電性や潤滑性が低下してトナーのチャージアップを発生する場合があり、スリーブゴースト、カブリ、画像濃度等の画質が悪化しやすくなり、さらに弾性ブレードを使用した場合にブレード傷が発生する場合があり、画像にスジ・濃度ムラ等が発生しやすくなる。焼成温度が３５００℃を超える場合は黒鉛化粒子の黒鉛化度が高すぎてしまう場合があり、そのため黒鉛化粒子の硬度が下がり、黒鉛化粒子の耐摩耗性の悪化により樹脂被覆層表面の耐摩耗性、樹脂被覆層の機械的強度及びトナーへの帯電付与性が低下することがある。
【００５８】
さらに、本発明に用いられる黒鉛化粒子は、黒鉛化度ｐ（００２）が、０．２０≦ｐ（００２）≦０．９５であることが好ましい。
【００５９】
上記の黒鉛化度ｐ（００２）とは、Ｆｒａｎｋｌｉｎのｐ値といわれるもので、黒鉛のＸ線回折図から得られる格子間隔ｄ（００２）を測定することで、ｄ（００２）＝３．４４０−０．０８６（１−ｐ²）で求められる。このｐ値は、炭素の六方網目平面積み重なりのうち、無秩序な部分の割合を示すもので、ｐ値が小さいほど黒鉛化度は大きい。
【００６０】
ｐ（００２）が０．９５を超える場合は、耐摩耗性には優れているが、導電性や潤滑性が低下してトナーのチャージアップを発生する場合があり、スリーブゴースト、カブリ、画像濃度等の画質が悪化しやすくなり、さらに弾性ブレードを使用した場合にはブレード傷が発生したり、画像にスジ・濃度ムラ等が発生しやすくなる。ｐ（００２）が０．２０未満の場合は、黒鉛化粒子の耐摩耗性の悪化により樹脂被覆層表面の耐摩耗性、樹脂被覆層の機械的強度及びトナーへの帯電付与性が低下してしまう場合がある。
【００６１】
また、前記のいずれの原材料から得られた黒鉛化粒子は、いずれの製法にかかわらず、分級により粒度分布をある程度均一にしておくことが、樹脂被覆層の表面形状を均一にするために好ましい。
【００６２】
本発明に使用される黒鉛化粒子としては、個数平均粒径が０．５μｍ〜２５μｍであることが好ましく、１μｍ〜２０μｍであることがより好ましい。
【００６３】
黒鉛化粒子の個数平均粒径が０．５μｍ未満では表面に均一な粗さを付与する効果と帯電性能を高める効果が少なく、現像剤への迅速且つ均一な帯電が不十分となると共に、樹脂被覆層の摩耗によるトナーのチャージアップ、トナー汚染及びトナー融着が発生し、ゴーストの悪化、画像濃度低下を生じやすくなる。個数平均粒径が２５μｍを超える場合には、樹脂被覆層表面の粗さが大きくなり過ぎ、トナーの帯電が十分に行なわれにくくなってしまうと共に、樹脂被覆層の機械的強度が低下してしまうことがある。
【００６４】
本発明においては、樹脂被覆層の体積抵抗値を調整する目的で、樹脂被覆層中に前記の黒鉛化粒子と併用して、導電剤を分散含有させても良い。本発明に用いられる導電剤としては、例えば個数平均粒径が１μｍ以下、好ましくは０．０１〜０．８μｍの導電性微粒子が挙げられる。該導電性微粒子の個数平均粒径が１μｍを超える場合には、樹脂被覆層の体積抵抗を低く制御しづらくなり、トナーのチャージアップによるトナー汚染が発生しやすくなる。
【００６５】
また、導電剤としては、アルミニウム、銅、ニッケル、銀等の金属粉体の微粉末、酸化アンチモン、酸化インジウム、酸化スズ、酸化チタン、酸化亜鉛、酸化モリブデン、チタン酸カリウム等の金属酸化物、各種カーボンファイバー、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、チャネルブラック等のカーボンブラック、グラファイト等の炭化物、さらには金属繊維等が挙げられる。
【００６６】
本発明においては、これらのうち、カーボンブラック、とりわけ導電性のアモルファスカーボンが、特に電気伝導性に優れ、高分子材料に充填して導電性を付与したり、その添加量をコントロールするだけで、ある程度任意の導電性を得ることができるため好適に用いられる。塗料にした場合の分散安定性も良好となりうる。また、本発明において好適なこれらの導電性物質の添加量は、結着樹脂１００質量部に対して１質量部〜１００質量部の範囲とすることが好ましい。１質量部未満では樹脂被覆層の抵抗値を所望のレベルに下げることは、通常困難であり、また、現像剤担持体表面の樹脂被覆層に用いられる結着樹脂に対するトナー付着が発生する可能性がある。１００質量部を超える場合は、特にサブミクロンオーダーの粒度を有する微粉体を用いた場合、樹脂被覆層の強度（耐摩耗性）が低下することがある。
【００６７】
本発明に使用することのできる樹脂被覆層中には、樹脂被覆層表面に凹凸を形成するための固体粒子を含有させることが可能である。このような固体粒子としては、例えば、ポリメチルメタクリレート、ポリエチルアクリレート、ポリブタジエン、ポリエチレン、ポリプロピレン、ポリスチレン等のビニル系重合体や共重合体、フェノール樹脂、ポリアミド樹脂、フッ素系樹脂、シリコーン樹脂、ポリエステル樹脂等の樹脂粒子、アルミナ、酸化亜鉛、シリコーン、酸化チタン、酸化錫等の酸化物粒子、炭素化粒子、導電処理を施した樹脂粒子等の導電性粒子、その他、例えばイミダゾール化合物のような有機化合物を粒子状にして用いることも可能である。この場合にイミダゾール化合物は、トナーに摩擦帯電電荷を付与する役割も果たす。
【００６８】
特に、上記固体粒子としては球状粒子が好ましく用いられ、球状の樹脂粒子としては、例えば、懸濁重合法、分散重合法等によって製造された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、さらに均一な表面形状が得られやすい。このような球状の樹脂粒子としては、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等が挙げられる。粉砕法により得られた樹脂粒子を熱的に或いは物理的な球形化処理を行ってから用いても良い。
【００６９】
その他、例えば球状の樹脂粒子の表面に無機微粉末を付着させる、或いは固着させて用いてもよい。このような無機微粉末としては、ＳｉＯ₂、ＳｒＴｉＯ₃、ＣｅＯ₂、ＣｒＯ、Ａｌ₂Ｏ₃、ＺｎＯ、ＭｇＯ、ＴｉＯ₂の如き酸化物、Ｓｉ₃Ｎ₄の如き窒化物、ＳｉＣの如き炭化物、ＣａＳＯ₄、ＢａＳＯ₄、ＣａＣＯ₃の如き硫酸塩・炭酸塩等が挙げられる。このような無機微粉末は、カップリング剤により処理して用いても良い。特に結着樹脂との密着性を向上させる目的、或いは粒子に疎水性を与える等の目的では好ましく用いることが可能である。
【００７０】
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２〜１２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個宛のケイ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。
【００７１】
このように球状樹脂粒子表面に対して無機微粉末で処理することにより、塗料中への分散性、塗工表面の均一性、樹脂被覆層の耐汚染性、トナーへの帯電付与性、樹脂被覆層の耐摩耗性等を向上させることができる。
【００７２】
球状粒子に耐汚染性、耐摩耗性などを持たせるために導電性の球状粒子を用いることもよい。導電性の球状粒子としては、例えば、導電処理された球状粒子として、酸化チタン、酸化ニオブ、酸化マンガン、酸化鉛等の金属酸化物や硫酸バリウム等の顔料の表面に、酸化スズ等の良導電性物質をコートしたもの；或いは酸化亜鉛、酸化銅、酸化イリジウム等の絶縁性金属酸化物中に、酸化数の異なる金属をドーピングして導電性を持たせたものがある。
【００７３】
導電性球状粒子の体積抵抗は１０⁶Ω・ｃｍ以下であることが好ましい。１０⁶Ω・ｃｍを超えるとトナーのチャージアップ等の弊害をもたらす場合がある。
【００７４】
添加される球状粒子の真密度は、３ｇ／ｃｍ³以下のものが好ましい。真密度が３ｇ／ｃｍ³を超えると、樹脂被覆層中で球状粒子の分散性が不十分になることがあるため、樹脂被覆層表面に均一な粗さを付与しにくくなり、トナーへの均一な帯電付与や樹脂被覆層の強度が不十分となり、さらにこれらの粒子の利点である耐汚染性や耐摩耗性が発揮できなくなる可能性がある。このような条件を満たす導電性球状粒子の種類としては、球状炭素粒子、導電性物質で表面処理された球状樹脂粒子、導電性微粒子が分散された球状樹脂粒子などが挙げられる。
【００７５】
これらの粒子の中では特に導電性の粒子を用いることが好ましい。このような粒子としては、本発明者らが先に提案した導電性球状粒子がある。即ち、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、トナー付着の軽減やトナー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、粒子の導電性としては、体積抵抗値が１０⁶Ω・ｃｍ以下、より好ましくは１０^-3〜１０⁶Ω・ｃｍの粒子であることが好ましい。このような粒子の体積抵抗が１０⁶Ω・ｃｍを超えると、摩耗によって樹脂被覆層表面に露出した球状粒子を核としてトナー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。さらには粒子の真密度としては３ｇ／ｃｍ³程度以下であることがより好ましい。導電性であっても、粒子の真密度が高すぎる場合、同じ粗さを形成するために添加量を増やさなければならず、また、樹脂または樹脂組成物と真密度差が大きくなるため、製造時の粒子の分散状態が非均一となりやすく、従って形成された樹脂被覆層においても分散状態が不均一になることがある。また粒子が球状であると、圧接される現像剤層厚規制部材等との接触面積が低減されるので、摩擦力によるスリーブ回転トルクの増加や、トナーの付着などを軽減することができるのでより好ましい。特に下記に示すような導電性の球状粒子を用いた場合には、より良い効果が得られる。
【００７６】
このような球状粒子の粒径は、個数平均粒径で０．３μｍ〜３０μｍが好ましい。０．３μｍ未満では均一に樹脂被覆層表面に凹凸を形成することが難しく、表面粗さを大きくしようとした場合添加量が過大になり、樹脂被覆層が脆くなり耐摩耗性が極端に低下することがある。逆に３０μｍより大きくなると、粒子が現像剤担持体表面から突出しすぎるため、現像剤層の厚みが大きくなり過ぎて現像剤の帯電が低下したり、不均一になりやすく、バイアスをかけた際に静電潜像担持体（感光ドラム）へリークするポイントになる場合がある。
【００７７】
さらに本発明の樹脂被覆層中には、必要に応じて荷電制御剤を含有させることができる。荷電制御剤としては、後述のトナー粒子形成に用いるものと同様なものが使用可能である。
【００７８】
本発明で好適に使用される上記のような構成を有する現像剤担持体表面の樹脂被覆層の表面粗さは、一般的には、ＪＩＳ中心線平均粗さ（Ｒａ）で０．３μｍ〜３．５μｍの範囲にあることが好ましい。ただし、その現像方式によって好ましい表面粗さは異なる。例えば、図５に示されるような、磁性トナーを用い、現像剤層厚規制部材として現像剤担持体と間隙をもって配置された磁性ブレードを有するような現像装置では、Ｒａが０．３μｍ〜２．５μｍ程度にあることが好ましい。Ｒａが０．３μｍ未満の場合には、現像剤の十分な搬送性が得られず、トナー不足による画像濃度薄や、トナーの過剰な帯電による飛び散りやブロッチなどが発生しやすい。また、２．５μｍより大きい場合には、トナーの摩擦帯電が不均一となり、スジむらや、反転カブリ、帯電不足による画像濃度薄などが発生しやすい。また例えば、図６に示されるような、弾性部材が現像剤担持体に圧接して用いられる現像装置の場合には、Ｒａが０．５μｍ〜３．５μｍ程度にあることが好ましい。Ｒａが０．５μｍより小さい場合には、現像剤の十分な搬送性が得られず、トナー不足による画像濃度薄や、トナーの過剰な帯電による飛び散りやブロッチなどが発生することがあり、また、現像剤担持体へのトナー融着も発生しやすい。また、３．５μｍより大きい場合には、トナーの摩擦帯電が不均一となり、スジむらや、反転カブリ、帯電不足による画像濃度薄などを発生しやすい。
【００７９】
さらに、本発明においては、現像剤担持体表面への現像剤の付着をより軽減化するため、樹脂被覆層中に固体潤滑剤を混合させることもできる。この際に使用し得る固体潤滑剤としては、例えば、二硫化モリブデン、窒化硼素、グラファイト、フッ化グラファイト、銀−セレンニオブ、塩化カルシウム−グラファイト、滑石等が挙げられる。また、本発明で使用することのできるこれらの固体潤滑剤の添加量は、結着樹脂１００質量部に対して１質量部〜１００質量部の範囲とすることが好ましい。１質量部未満では樹脂被覆層の結着樹脂表面に対する現像剤の付着性の改善効果は少なく、１００質量部を超えると、特にサブミクロンオーダーの粒度を有する微粉体が多く含まれる材料を用いた場合、樹脂被覆層の強度（摩耗性）が低下しうる。これらの固体潤滑剤は、個数平均粒径が好ましくは０．２μｍ〜２０μｍ程度、より好ましくは１μｍ〜１５μｍのものを使用するのが良い。固体潤滑剤の個数平均粒径が０．２μｍ未満の場合には、潤滑性が十分に得られ難くなり、個数平均粒径が２０μｍを超える場合には、樹脂被覆層表面の形状への影響が大きく表面性が不均一となりやすく、トナーの均一な帯電化、及び樹脂被覆層の強度の点で不十分になることがある。
【００８０】
本発明の現像剤担持体の樹脂被覆層を得る方法としては、例えば、各成分を溶剤中に分散混合して塗料化し、前記基体上に塗工することにより得る方法が挙げられる。塗料の各成分の分散混合には、サンドミル、ペイントシェーカー、ダイノミル、パールミル等のビーズを利用した公知の分散装置が好適に利用可能である。また塗工方法としては、ディッピング法、スプレー法、ロールコート法等公知の方法が適用可能である。
【００８１】
次に本発明の現像装置について説明する。
【００８２】
本発明の現像装置は、現像剤を収容するための現像容器、該現像容器に収容されている現像剤を担持し、現像領域に搬送するための現像剤担持体、及び該現像剤担持体上に担持される現像剤の層厚を規制するための現像剤層厚規制部材を少なくとも有する現像装置であって、該現像剤担持体として、上記した本発明の現像剤担持体を用いることを特徴とする。
【００８３】
図５は、本発明の現像装置の一実施形態の模式図である。
【００８４】
図５において、公知のプロセスにより形成された静電潜像を担持する静電潜像担持体、例えば、感光ドラム５１は、矢印Ｂ方向に回転する。現像剤担持体としての現像スリーブ５８は、現像容器５３に供給された磁性トナーを有する一成分系現像剤を担持して、矢印Ａ方向に回転することによって、現像剤担持体たる現像スリーブ５８と感光ドラム５１とが対向している現像領域Ｄに現像剤を搬送する。図５に示すように、現像ローラー６０においては、現像スリーブ５８内に、現像剤を現像スリーブ５８上に磁気的に吸引且つ保持するために、磁石（マグネットローラー）５９が配置されている。
【００８５】
本発明の現像装置で用いられる現像スリーブ５８は、基体としての金属円筒管５６上に被覆された樹脂被覆層５７を有する。現像容器５３中には、ここには図示されていない現像剤補給容器から現像剤供給部材（スクリューなど）６２を経由して現像剤が送り込まれてくる。現像容器は、第一室６４、第二室６５に分割されており、第一室６４に送り込まれた現像剤は攪拌搬送部材５５により現像容器５３及び仕切り部材５４により形成される隙間を通過して第二室６５に送られる。現像剤はマグネットローラー５９による磁力の作用により現像スリーブ５８上に担持される。第二室６５中には現像剤が滞留するのを防止するための攪拌部材６１が設けられている。
【００８６】
現像剤は、磁性トナー相互間及び現像スリーブ５８上の樹脂被覆層５７との摩擦により、感光ドラム５１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５の例では、現像領域Ｄに搬送される現像剤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ブレード（ドクターブレード）５２が、現像スリーブ５８の表面から約５０μｍ〜５００μｍの間隙を有して現像スリーブ５８に対向するように現像容器５３に装着されている。マグネットローラー５９の磁極Ｎ１からの磁力線が磁性規制ブレード５２に集中することにより、現像スリーブ５８上に現像剤の薄層が形成される。本発明においては、この磁性規制ブレード５２にかえて非磁性の規制ブレードを使用することもできる。
【００８７】
この様にして、現像スリーブ５８上に形成される現像剤の薄層の厚みは、現像領域Ｄにおける現像スリーブ５８と感光ドラム５１との間の最小間隙よりもさらに薄いものであることが好ましい。
【００８８】
本発明の現像剤担持体は、以上の様な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５８と感光ドラム５１との間の最小間隙以上の厚みである現像装置、所謂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。尚、説明の煩雑を避けるため、以下の説明では先に説明した非接触型現像装置を例にとって行なう。
【００８９】
上記現像スリーブ５８に担持された磁性トナーを有する一成分系現像剤を飛翔させるため、上記現像スリーブ５８にはバイアス手段としての現像バイアス電源６３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５８に印加するのが好ましい。
【００９０】
現像された画像の濃度を高め、且つ階調性を向上させるためには、現像スリーブ５８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５８に印加するのが好ましい。
【００９１】
この時、高電位部と低電位部を有する静電潜像の高電位部にトナーを付着させて可視化する、所謂正規現像の場合には、静電潜像の極性と逆極性に帯電するトナーを使用し、高電位部と低電位部を有する静電潜像の低電位部にトナーを付着させて可視化する、所謂反転現像の場合には、静電潜像の極性と同極性に帯電するトナーを使用する。この場合、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（トナー）は少なくとも現像スリーブ５８表面（樹脂被覆層５７）との摩擦により帯電する。
【００９２】
図５においては、現像スリーブ５８上の現像剤の層厚を規制する現像剤層厚規制部材として、現像スリーブから離間されて配置された磁性ブレードの例を示したが、図６に示される如く、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弾性規制ブレードを使用し、この弾性規制ブレード６７を現像スリーブに対して、トナーを介して接触或いは圧接させて用いても良く、本発明においては特にこの形態を有する系において、従来技術と比較して、耐摩耗性及び帯電付与能の面で格段の効果を得ることができる。これは、規制ブレードを接触または圧接させるタイプの現像装置では、トナー層はさらに強い規制を受けながら現像スリーブ５８上に現像剤の薄層を形成することから、現像スリーブ５８上に、上記した図５の引用例の場合よりもさらに薄い現像剤層を形成することができるため、現像スリーブ５８表面の樹脂被覆層への負荷が大きくなり、樹脂被覆層が摩耗し易くなる。本発明では、このような系においても樹脂被覆層の摩耗を軽減することができるため、高耐久化を達成することができる。尚、現像スリーブ５８に対する弾性規制ブレード６７の当接圧力は、線圧５ｇ／ｃｍ〜５０ｇ／ｃｍであることが、トナーの規制を安定化させ、トナー層厚を好適にさせることができる点で好ましい。弾性規制ブレード６７の当接圧力が線圧５ｇ／ｃｍ未満の場合には、トナーの規制が弱くなり、カブリやトナーもれの原因となり、線圧５０ｇ／ｃｍを超える場合には、トナーへのダメージが大きくなり、トナー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。
【００９３】
図５及び図６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、前記した層厚規制部材以外にも、現像容器５３（ホッパー）の形状、攪拌翼５５、６１の有無、磁極の配置、供給部材６２の形状、補給容器の有無、などに様々な形態があることは言うまでもない。
【００９４】
図７に、本発明のプロセスカートリッジの一実施形態を示す。本発明のプロセスカートリッジは、少なくとも現像手段と静電潜像保持体とが一体的にカートリッジ化されたものであり、画像形成装置本体（例えば、複写機、レーザービームプリンター、ファクシミリ装置）に着脱可能に構成されている。
【００９５】
図７に示した実施形態では、現像手段７１、ドラム状の静電潜像担持体（感光ドラム）５１、クリーニングブレード７２ａを有するクリーニング手段７２、一次帯電手段としての接触（ローラー）帯電手段７３を一体としたプロセスカートリッジ７０が例示される。本実施形態では、現像手段７１は、現像スリーブ５８と、弾性規制ブレード６７と現像容器５３内に磁性トナーを有する一成分系現像剤（トナー）Ｔとを有し、該トナーＴを用い、現像時にはバイアス印加手段からの現像バイアス電圧により感光ドラム５１と現像スリーブ５８との間に所定の電界が形成されて現像工程が実施される。この現像工程を好適に実施するためには、感光ドラム５１と現像スリーブ５８との間の距離が非常に大切である。
【００９６】
上記では、現像手段７１、静電潜像担持体５１、クリーニング手段７２及び一次帯電手段７３の４つの構成要素を一体的にカートリッジ化した実施形態について説明したが、本発明においては、現像手段と静電潜像担持体との少なくも２つの構成要素が一体的にカートリッジ化されたものであればよく、現像手段、静電潜像担持体及びクリーニング手段の３つの構成要素、現像手段、静電潜像担持体及び一次帯電手段の３つの構成要素、或いは、その他の構成要素を加えて一体的にカートリッジ化することも可能である。
【００９７】
次に、本発明の現像装置で用いられる現像剤について説明する。
【００９８】
本発明にて使用できる現像剤は、少なくとも結着樹脂と着色剤、必要に応じて各種添加剤を含有するトナー粒子に、さらに必要に応じて、各種添加剤を外添したトナーからなる。尚、一成分系現像剤においては、実質的にトナーが現像剤を意味する。該トナーの重量平均粒径は４μｍ〜１１μｍであることが好ましい。このようなものを使用すれば、トナーの帯電量或いは画質及び画像濃度等がバランスのとれたものとなる。
【００９９】
トナーの結着樹脂としては、一般に公知の樹脂が使用可能であり、例えばビニル系樹脂、ポリエステル樹脂、ポリウレタン樹脂、エポキシ樹脂、フェノール樹脂等が挙げられるが、この中でも特にビニル系樹脂、ポリエステル樹脂が好ましい。
【０１００】
ビニル系樹脂において用いることのできるカルボン酸含有モノマーとしては、特にジカルボン酸の半エステルモノマーが好ましく、例えばマレイン酸モノメチル、マレイン酸モノエチル、マレイン酸モノブチル、マレイン酸モノオクチル、マレイン酸モノアリル、マレイン酸モノフェニル、フマル酸モノメチル、フマル酸モノエチル、フマル酸モノブチル、フマル酸モノフェニルなどのようなα，β−不飽和ジカルボン酸の半エステル類；ｎ−ブテニルコハク酸モノブチル、ｎ−オクテニルコハク酸モノメチル、ｎ−ブテニルマロン酸モノエチル、ｎ−ドデセニルグルタン酸モノメチル、ｎ−ブテニルアジピン酸モノブチルなどのようなアルケニルジカルボン酸の半エステル類；フタル酸モノメチルエステル、フタル酸モノエチルエステル、フタル酸モノブチルエステルなどのような芳香族ジカルボン酸の半エステル類；などが挙げられる。
【０１０１】
さらに本発明に用いることのできるビニル系樹脂を得るためのカルボン酸含有モノマー以外のコモノマーとしては、次のようなものが挙げられる。
【０１０２】
例えばスチレン、ｏ−メチルスチレン、ｍ−メチルスチレン、ｐ−メチルスチレン、ｐ−メトキシスチレン、ｐ−フェニルスチレン、ｐ−クロルスチレン、３，４−ジクロルスチレン、ｐ−エチルスチレン、２，４−ジメチルスチレン、ｐ−ｎ−ブチルスチレン、ｐ−ｔｅｒｔ−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−ドデシルスチレン等のスチレン及びその誘導体；エチレン、プロピレン、ブチレン、イソブチレンなどのエチレン不飽和モノオレフィン類；ブタジエン等の不飽和ポリエン類；塩化ビニル、塩化ビニリデン、臭化ビニル、弗化ビニルなどのハロゲン化ビニル類；酢酸ビニル、プロピオン酸ビニル、ベンゾエ酸ビニルなどのビニルエステル類；メタクリル酸メチル、メタクリル酸エチル、メタクリル酸プロピル、メタクリル酸ｎ−ブチル、メタクリル酸イソブチル、メタクリル酸ｎ−オクチル、メタクリル酸ドデシル、メタクリル酸−２−エチルヘキシル、メタクリル酸ステアリル、メタクリル酸フェニル、メタクリル酸ジメチルアミノエチル、メタクリル酸ジエチルアミノエチルなどのα−メチレン脂肪族モノカルボン酸エステル類；アクリル酸メチル、アクリル酸エチル、アクリル酸ｎ−ブチル、アクリル酸イソブチル、アクリル酸プロピル、アクリル酸ｎ−オクチル、アクリル酸ドデシル、アクリル酸２−エチルヘキシル、アクリル酸ステアリル、アクリル酸２−クロルエチル、アクリル酸フェニルなどのアクリル酸エステル類；ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソブチルエーテルなどのビニルエーテル類；ビニルメチルケトン、ビニルヘキシルケトン、メチルイソプロペニルケトンなどのビニルケトン類；Ｎ−ビニルピロール、Ｎ−ビニルカルバゾール、Ｎ−ビニルインドール、Ｎ−ビニルピロリドンなどのＮ−ビニル化合物；ビニルナフタリン類；アクリロニトリル、メタクリロニトリル、アクリルアミドなどのアクリル酸もしくはメタクリル酸誘導体；のビニル系モノマーが単独もしくは２つ以上で用いられる。
【０１０３】
これらの中でもスチレン系共重合体、スチレン−アクリル系共重合体となるようなモノマーの組み合わせが好ましい。
【０１０４】
また架橋性モノマーとしては主として２個以上の重合可能な二重結合を有するモノマーが用いられる。
【０１０５】
本発明に用いることのできるビニル系重合体は、以下に例示する様な架橋性モノマーで架橋された重合体であってもよい。
【０１０６】
芳香族ジビニル化合物、例えば、ジビニルベンゼン、ジビニルナフタレン等；アルキル鎖で結ばれたジアクリレート化合物類、例えば、エチレングリコールジアクリレート、１，３−ブチレングリコールジアクリレート、１，４−ブタンジオールジアクリレート、１，５−ペンタンジオ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、及び以上の化合物のアクリレートをメタクリレートに代えたもの；エーテル結合を含むアルキル鎖で結ばれたジアクリレート化合物類、例えば、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＃４００ジアクリレート、ポリエチレングリコール＃６００ジアクリレート、ジプロピレングリコールジアクリレート、及び以上の化合物のアクリレートをメタアクリレートに代えたもの；芳香族基及びエーテル結合を含む鎖で結ばれたジアクリレート化合物類、例えば、ポリオキシエチレン（２）−２，２−ビス（４−ヒドロキシフェニル）プロパンジアクリレート、ポリオキシエチレン（４）−２，２−ビス（４−ヒドロキシフェニル）プロパンジアクリレート、及び、以上の化合物のアクリレートをメタクリレートに代えたもの；さらには、ポリエステル型ジアクリレート化合物類、例えば、商品名ＭＡＮＤＡ（日本化薬）が挙げられる。多官能の架橋剤としては、ペンタエリスリトールトリアクリレート、トリメチロールエタントリアクリレート、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、オリゴエステルアクリレート、及び以上の化合物のアクリレートをメタクリレートに代えたもの；トリアリルシアヌレート、トリアリルトリメリテート；等が挙げられる。
【０１０７】
これらの架橋剤は、他のモノマー成分１００質量部に対して、０．０１質量部〜５質量部（好ましくは０．０３質量部〜３質量部）用いることが好ましい。
【０１０８】
これらの中でも特に、芳香族ジビニル化合物（特にジビニルベンゼン）、芳香族基及びエーテル結合を含む鎖で結ばれたジアクリレート化合物類が好ましく用いることができる。
【０１０９】
また、現像剤が負帯電性である場合、ポリエステル樹脂を使用することは好例の一つであり、該ポリエステル樹脂としては、多塩基酸成分及び多価アルコール成分の縮重合体よりなるポリエステル樹脂が好ましい。
【０１１０】
本発明に用いることのできるポリエステル樹脂の組成は以下の通りである。
【０１１１】
２価のアルコール成分としては、エチレングリコール、プロピレングリコール、１，３−ブタンジオール、１，４−ブタンジオール、２，３−ブタンジオール、ジエチレングリコール、トリエチレングリコール、１，５−ペンタンジオール、１，６−ヘキサンジオール、ネオペンチルグリコール、２−エチル−１，３−ヘキサンジオール、水素化ビスフェノールＡ、また下記式（Ａ）で表わされるビスフェノール及びその誘導体；
【０１１２】
【化３】

【０１１３】
（上記式中、Ｒはエチレンまたはプロピレン基であり、ｘ，ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）
【０１１４】
また、下記式（Ｂ）で示されるジオール類；
【０１１５】
【化４】

等のジオール類、が挙げられる。
【０１１６】
２価の酸成分としては、フタル酸、テレフタル酸、イソフタル酸、無水フタル酸などのベンゼンジカルボン酸類またはその無水物、低級アルキルエステル；こはく酸、アジピン酸、セバシン酸、アゼライン酸などのアルキルジカルボン酸類またはその無水物、低級アルキルエステル；ｎ−ドデセニルコハク酸、ｎ−ドデシルコハク酸等のアルケニルコハク酸もしくはアルキルコハク酸、またはその酸の無水物、低級アルキルエステル；フマル酸、マレイン酸、シトラコン酸、イタコン酸などの不飽和ジカルボン酸またはその無水物、低級アルキルエステル等のジカルボン酸類及びその誘導体が挙げられる。
【０１１７】
また、架橋成分としても働く３価以上のアルコール成分と３価以上の酸成分を併用することができる。
【０１１８】
３価以上の多価アルコール成分としては、ソルビトール、１，２，３，６−ヘキサンテトロール、１，４−ソルビタン、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、１，２，４−ブタントリオール、１，２，５−ペンタントリオール、グリセロール、２−メチルプロパントリオール、２−メチル−１，２，４−ブタントリオール、トリメチロールエタン、トリメチロールプロパン、１，３，５−トリヒドロキシベンゼン、等の３価以上の多価アルコール類が挙げられる。
【０１１９】
また３価以上の多価カルボン酸成分としては、トリメリット酸、ピロメリット酸、１，２，４−ベンゼントリカルボン酸、１，２，５−ベンゼントリカルボン酸、２，５，７−ナフタレントリカルボン酸、１，２，４−ナフタレントリカルボン酸、１，２，４−ブタントリカルボン酸、１，２，５−ヘキサントリカルボン酸、１，３−ジカルボキシル−２−メチル−２−メチレンカルボキシプロパン、テトラ（メチレンカルボキシル）メタン、１，２，７，８−オクタンテトラカルボン酸、エンポール三量体酸、及びこれらの無水物、低級アルキルエステル、下記式（Ｃ）で表わされるテトラカルボン酸等、及びこれらの無水物、低級アルキルエステル等の多価カルボン酸類及びその誘導体が挙げられる。
【０１２０】
【化５】

【０１２１】
（上記式中、Ｘは炭素数３以上の側鎖を１個以上有する炭素数５〜３０のアルキレン基またはアルケニレン基を示す。）
【０１２２】
本発明に用いられるアルコール成分としては４０モル％〜６０モル％、好ましくは４５モル％〜５５モル％、酸成分としては６０モル％〜４０モル％、好ましくは５５モル％〜４５モル％であることが好ましい。
【０１２３】
また３価以上の多価の成分は、全成分中の５モル％〜６０モル％であることが好ましい。
【０１２４】
本発明において好ましいポリエステル樹脂のアルコール成分としては、前記式（Ａ）で示されるビスフェノール誘導体であり、酸成分としては、フタル酸、テレフタル酸、イソフタル酸またはその無水物；こはく酸、ｎ−ドデセニルコハク酸またはその無水物、フマル酸、マレイン酸、無水マレイン酸等のジカルボン酸類、トリメリット酸またはその無水物のトリカルボン酸類が挙げられる。
【０１２５】
これらの酸、アルコールで得られたポリエステル樹脂を有する負帯電性現像剤は、帯電特性に優れており、本発明において好ましく用いられる。
【０１２６】
このようにして得られた結着樹脂のガラス転移温度（Ｔｇ）は、４５℃〜７５℃好ましくは５０℃〜７０℃、さらに数平均分子量（Ｍｎ）１，５００〜３０，０００好ましくは２，０００〜１５，０００、重量平均分子量（Ｍｗ）６，０００〜８００，０００好ましくは１０，０００〜５００，０００であることが、本発明の現像装置に用いられる現像剤に好適である。
【０１２７】
本発明の現像装置に用いられる現像剤においては、帯電特性を向上させる目的で、荷電制御剤をトナー粒子に配合（内添）、またはトナー粒子と混合（外添）して用いることができる。これは、荷電制御剤によって、現像システムに応じた最適の荷電量コントロールが可能となるためである。
【０１２８】
例えば、正の荷電制御剤としては、ニグロシン、トリアミノトリフェニルメタン系染料及び脂肪酸金属塩等による変性物；トリブチルベンジルアンモニウム−１−ヒドロキシ−４−ナフトスルフォン酸塩、テトラブチルアンモニウムテトラフルオロボレートなどの四級アンモニウム塩；ジブチルスズオキサイド、ジオクチルスズオキサイド、ジシクロヘキシルスズオキサイドなどのジオルガノスズオキサイド；ジブチルスズボレート、ジオクチルスズボレード、ジシクロヘキシルスズボレートなどのジオルガノスズボレートを単独或いは２種類以上組み合わせて用いることができる。これらの中でも、ニグロシン系化合物、トリアミノトリフェニルメタン系染料、有機四級アンモニウム塩の如き荷電制御剤が特に好ましく用いられる。
【０１２９】
また負の荷電制御剤としては、例えば有機金属化合物、キレート化合物が有効である。その例としてはアルミニウムアセチルアセトナート、鉄（ＩＩ）アセチルアセトナート、３，５−ジ−ｔｅｒｔ−ブチルサリチル酸クロム等があり、特にアセチルアセトン金属錯体、モノアゾ金属錯体、ナフトエ酸或いはサリチル酸系の金属錯体または塩が好ましく、特にサリチル酸系金属錯体、モノアゾ金属錯体またはサリチル酸系金属塩が好ましい。
【０１３０】
上述した荷電制御剤は、微粒子状として用いることが好ましい。この場合、この荷電制御剤の個数平均粒径は、具体的には４μｍ以下、さらには３μｍ以下が好ましい。
【０１３１】
上記荷電制御剤をトナー粒子に内添する際には、トナー粒子を構成する結着樹脂１００質量部に対して０．１質量部〜２０質量部用いることが好ましく、より好ましくは０．２質量部〜１０質量部用いる。
【０１３２】
また、本発明に用いることのできる現像剤が磁性現像剤である場合、トナー粒子に配合される磁性材料としては、マグネタイト、マグヘマイト、フェライト等の酸化鉄、及び他の金属酸化物を含む酸化鉄；Ｆｅ、Ｃｏ、Ｎｉのような金属、或いは、これらの金属とＡｌ、Ｃｏ、Ｃｕ、Ｐｂ、Ｍｇ、Ｎｉ、Ｓｎ、Ｚｎ、Ｓｂ、Ｂｅ、Ｂｉ、Ｃｄ、Ｃａ、Ｍｎ、Ｓｅ、Ｔｉ、Ｗ、Ｖのような金属との合金、及びこれらの混合物等が挙げられる。
【０１３３】
磁性材料としては、従来、四三酸化鉄（Ｆｅ₃Ｏ₄）、三二酸化鉄（γ−Ｆｅ₂Ｏ₃）、酸化鉄亜鉛（ＺｎＦｅ₂Ｏ₄）、酸化鉄イットリウム（Ｙ₃Ｆｅ₅Ｏ₁₂）、酸化鉄カドミウム（ＣｄＦｅ₂Ｏ₄）、酸化鉄ガドリニウム（Ｇｄ₃Ｆｅ₅−Ｏ₁₂）、酸化鉄銅（ＣｕＦｅ₂Ｏ₄）、酸化鉄鉛（ＰｂＦｅ₁₂−Ｏ₁₉）、酸化鉄ニッケル（ＮｉＦｅ₂Ｏ₄）、酸化鉄ネオジム（ＮｄＦｅ₂Ｏ₃）、酸化鉄バリウム（ＢａＦｅ₁₂Ｏ₁₉）、酸化鉄マグネシウム（ＭｇＦｅ₂Ｏ₄）、酸化鉄マンガン（ＭｎＦｅ₂Ｏ₄）、酸化鉄ランタン（ＬａＦｅＯ₃）、鉄粉（Ｆｅ）、コバルト粉（Ｃｏ）、ニッケル粉（Ｎｉ）等が知られているが、本発明の現像装置に使用可能な現像剤には、上述した磁性材料を単独で或いは２種以上の組合せで選択使用する。上記に挙げた中でも、特に好適な磁性材料は四三酸化鉄またはγ−三二酸化鉄の微粉末である。これらの強磁性体は、平均粒径が０．１μｍ〜２μｍ程度で、７９５８ｋＡ／ｍ（１０ｋエルステッド）印加での磁気特性が、保磁力（Ｈ_c）１．６ｋＡ／ｍ〜１６ｋＡ／ｍ、飽和磁化（σ_s）５０Ａｍ²／ｋｇ〜２００Ａｍ²／ｋｇ、残留磁化（σ_r）２Ａｍ²／ｋｇ〜２０Ａｍ²／ｋｇのものが好ましい。
【０１３４】
結着樹脂１００質量部に対して、磁性体１０質量部〜２００質量部、好ましくは２０質量部〜１５０質量部使用するのが良い。
【０１３５】
尚、上記磁性体に、着色剤としての役目を兼用させて使用してもかまわない。
【０１３６】
本発明に用いることのできる現像剤において、トナー粒子に含有させうる着色剤としては、任意の適当な顔料または染料が挙げられる。
【０１３７】
例えば顔料としてカーボンブラック、アニリンブラック、アセチレンブラック、ナフトールイエロー、ハンザイエロー、ローダミンレーキ、アリザリンレーキ、ベンガラ、フタロシアニンブルー、インダンスレンブルーが挙げられる。これら顔料は、結着樹脂１００質量部に対し、０．１質量部〜２０質量部、好ましくは１質量部〜１０質量部で使用することが好ましい。同様の目的で、さらに染料が用いられる。例えばアゾ系染料、アントラキノン系染料、キサンテン系染料、メチン系染料があり、結着樹脂１００質量部に対し、０．１質量部〜２０質量部、好ましくは０．３質量部〜１０質量部で使用することが好ましい。
【０１３８】
また、本発明に用いられる現像剤には、必要に応じて一種または二種以上の離型剤を、トナー粒子中に含有させてもかまわない。
【０１３９】
離型剤としては、低分子量ポリエチレン、低分子量ポリプロピレン、マイクロクリスタリンワックス、パラフィンワックスなどの脂肪族炭化水素系ワックス、また、酸化ポリエチレンワックスなどの脂肪族炭化水素系ワックスの酸化物、または、それらのブロック共重合物；カルナバワックス、フィッシャートロプシュワックス、サゾールワックス、モンタン酸エステルワックスなどの脂肪酸エステルを主成分とするワックス類、及び脱酸カルナバワックスなどの脂肪酸エステル類を一部または全部を脱酸化したものなどが挙げられる。さらに、パルミチン酸、ステアリン酸、モンタン酸などの、飽和直鎖脂肪酸類、ブランジン酸、エレオステアリン酸、バリナリン酸などの不飽和脂肪酸類、ステアリルアルコール、アラルキルアルコール、ベヘニルアルコール、カルナウビルアルコール、セリルアルコール、メリシルアルコールなどの飽和アルコール類、ソルビトールなどの多価アルコール類、リノール酸アミド、オレイン酸アミド、ラウリン酸アミドなどの脂肪酸アミド類、メチレンビスステアリン酸アミド、エチレンビスカプリン酸アミド、エチレンビスラウリン酸アミド、ヘキサメチレンビスステアリン酸アミドなどの飽和脂肪酸ビスアミド類、エチレンビスオレイン酸アミド、ヘキサメチレンビスオレイン酸アミド、Ｎ，Ｎ’−ジオレイルアジピン酸アミド、Ｎ，Ｎ’−ジオレイルセバシン酸アミドなどの、不飽和脂肪酸アミド類、ｍ−キシレンビスステアリン酸アミド、Ｎ，Ｎ’−ジステアリルイソフタル酸アミドなどの芳香族系ビスアミド類、ステアリン酸カルシウム、ラウリン酸カルシウム、ステアリン酸亜鉛、ステアリン酸マグネシウムなどの脂肪酸金属塩（一般に金属石けんといわれているもの）、また、脂肪族炭化水素系ワックスにスチレンやアクリル酸などのビニル系モノマーを用いてグラフト化させたワックス類、また、ベヘニン酸モノグリセリドなどの脂肪酸と多価アルコールの部分エステル化物、また、植物性油脂の水素添加などによって得られるヒドロキシル基を有するメチルエステル化合物などが挙げられる。
【０１４０】
上記離型剤は、結着樹脂１００質量部あたり０．１質量部〜２０質量部、好ましくは０．５質量部〜１０質量部用いることが好ましい。
【０１４１】
また、これらの離型剤は、通常、樹脂を溶剤に溶解し、樹脂溶液温度を上げ、撹拌しながら添加混合する方法や、混練時に混合する方法で結着樹脂に含有させられる。
【０１４２】
本発明に使用できる現像剤には、環境安定性、帯電安定性、現像性、流動性、保存性向上及びクリーニング性向上のために、シリカ微粉体、酸化チタン、アルミナ等の無機微粉体を外添、即ちトナー粒子表面近傍に存在させていることが好ましい。特にこの中でも、シリカ微粉体が好ましい。
【０１４３】
例えば、かかるシリカ微粉体はケイ素ハロゲン化物の蒸気相酸化により生成されたいわゆる乾式法またはヒュームドシリカと称される乾式シリカ、及び水ガラス等から製造されるいわゆる湿式シリカの両者が使用可能であるが、表面及びシリカ微粉体の内部にあるシラノール基が少なく、またＮａ₂Ｏ、ＳＯ₃ ^2-等の製造残滓の少ない乾式シリカの方が好ましい。また乾式シリカにおいては、製造工程において例えば、塩化アルミニウム、塩化チタン、等他の金属ハロゲン化合物をケイ素ハロゲン化合物と共に用いることによって、シリカと他の金属酸化物の複合微粉体を得ることも可能でありそれらも包含する。
【０１４４】
本発明で用いることのできる無機微粉体としては、有機処理された無機微粉体を用いることもできる。このような有機処理方法としては、前記無機微粉体と反応或いは物理吸着するシランカップリング剤、チタンカップリング剤等の有機金属化合物で処理する方法がある。このような処理を施すことにより、無機微粉体の疎水化が促進でき、特に高湿度下での環境安定性により優れたトナーを得ることができるため、好ましく用いることができる。有機処理に使用されるシランカップリング剤としては、例えば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分子当り２〜１２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個宛のケイ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。
【０１４５】
また、窒素原子を有するアミノプロピルトリメトキシシラン、アミノプロピルトリエトキシシラン、ジメチルアミノプロピルトリメトキシシラン、ジエチルアミノプロピルトリメトキシシラン、ジプロピルアミノプロピルトリメトキシシラン、ジブチルアミノプロピルトリメトキシシラン、モノブチルアミノプロピルトリメトキシシラン、ジオクチルアミノプロピルジメトキシシラン、ジブチルアミノプロピルジメトキシシラン、ジブチルアミノプロピルモノメトキシシラン、ジメチルアミノフェニルトリエトキシシラン、トリメトキシシリル−γ−プロピルフェニルアミン、トリメトキシシリル−γ−プロピルベンジルアミン等のシランカップリング剤も単独或いは併用して使用される。好ましい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（ＨＭＤＳ）、アミノプロピルトリメトキシシランが挙げられる。
【０１４６】
上記シランカップリング剤により無機微粉体を処理する方法としては、例えば、スプレー法、有機溶媒法、水溶液法等があるが、特に限定されるものではない。
【０１４７】
他の有機処理として、シリコーンオイルで処理された微粉体を用いることも可能である。好ましいシリコーンオイルとしては、２５０℃における粘度が０．５ｍｍ²／ｓ〜１００００ｍｍ²／ｓ、好ましくは１ｍｍ²／ｓ〜１０００ｍｍ²／ｓのものが用いられ、例えば、メチルハイドロジェンシリコーンオイル、ジメチルシリコーンオイル、フェニルメチルシリコーンオイル、クロルメチルシリコーンオイル、アルキル変性シリコーンオイル、脂肪酸変性シリコーンオイル、ポリオキシアルキレン変性シリコーンオイル、フッ素変性シリコーンオイル等が挙げられる。
【０１４８】
本発明に用いられる無機微粉体は、ＢＥＴ法で測定した窒素吸着による比表面積が３０ｍ²／ｇ以上、特に５０ｍ²／ｇ〜４００ｍ²／ｇの範囲のものが良好な結果を与え、また本発明に用いられる無機微粉体はトナー粒子１００質量部に対して０．０１質量部〜８質量部使用されるのが良く、好ましくは０．１質量部〜５質量部、特に好ましくは０．２質量部〜３質量部が良い。０．０１質量部未満では、現像剤の凝集を改善する効果が乏しくなり、また８質量部を超える場合では、上記無機微粉体がトナー粒子表面に付着せずに、遊離した状態で存在するものが生じやすくなり、現像剤が均一で且つ適切な帯電量を維持することが困難になり、現像特性の低下等の弊害をもたらす場合がある。
【０１４９】
本発明に用いることのできる現像剤には、上記無機微粉体以外の外添剤をさらに加えて用いても良い。例えば、テフロン（登録商標）、ステアリン酸亜鉛、ポリフッ化ビニリデンの如き滑剤、中でもポリフッ化ビニリデンが好ましい。或いは酸化セリウム、チタン酸ストロンチウム、ケイ酸ストロンチウム等の研磨剤、中でもチタン酸ストロンチウムが好ましい。その他ケーキング防止剤、或いは、例えばカーボンブラック、酸化亜鉛、酸化アンチモン、酸化スズ等の導電性付与剤、または逆極性の白色微粒子及び黒色微粒子を現像性向上剤として少量用いることもできる。
【０１５０】
これらの外添剤は、トナー粒子１００質量部に対して、０．０１質量部〜１０質量部（好ましくは０．１質量部〜７質量部）使用するのが良い。
【０１５１】
現像剤を作成するには、結着樹脂、着色剤としての顔料または染料、磁性体、離型剤、必要に応じて荷電制御剤、その他の添加剤をヘンシェルミキサー、ボールミキサー等の混合機により充分に混合してから加熱ロール、ニーダー、エクストルーダーのごとき熱混練機を用いて溶融して樹脂類を互いに相溶せしめた中に離型剤、顔料、染料、磁性体を分散または溶解せしめ、冷却固化後、粉砕及び分級を行なってトナー粒子を得ることができる。さらに、必要に応じて所望の添加剤をヘンシェルミキサー等の混合機により充分に混合し、トナー（現像剤）を得ることができる。
【０１５２】
このようなトナーは、種々の方法で、球形化処理、表面平滑化処理を施して用いると、転写性が良好となり好ましい。そのような方法としては、攪拌羽根またはブレードなど、及びライナーまたはケーシングなどを有する装置で、例えば、トナーをブレードとライナーの間の微小間隙を通過させる際に、機械的な力により表面を平滑化したりトナーを球形化したりする方法、温水中にトナーを懸濁させ球形化する方法、熱気流中にトナーを曝し、球形化する方法等がある。また、球状のトナーを直接作る方法としては、水中にトナー結着樹脂となる単量体を主成分とする混合物を懸濁させ、重合してトナー化する方法がある。一般的な方法としては、重合性単量体、着色剤、重合開始剤、さらに必要に応じて架橋剤、荷電制御剤、離形剤、その他の添加剤を均一に溶解または分散せしめて単量体組成物とした後、この単量体組成物を分散安定剤を含有する連続層、例えば水相中に適当な攪拌機を用いて適度な粒径に分散し、さらに重合反応を行わせ、所望の粒径を有する現像剤を得る方法である。
【０１５３】
以下に本発明に関わる物性の測定方法について述べる。
【０１５４】
（１）樹脂被覆層の形成に使用される結着樹脂の帯電極性の測定
サンプル板の作製方法：帯電極性を測定する樹脂被覆層（導電性物質を除いたもの）の形成に使用する樹脂を有機溶剤に溶解或いは分散させた溶液をＳＵＳ板上にバーコーター（＃６０）にて塗布し、これを乾燥・加熱等によって成膜させ（乾燥・加熱温度及び時間は、熱可塑性樹脂の場合は溶液が完全に蒸発するまで、熱硬化性樹脂の場合は樹脂の架橋が完全に行われるまで）、サンプル板を作製する。このサンプル板を接地した状態で、２３℃、６０％ＲＨ環境下にて一晩以上放置する。
【０１５５】
粒子の調整方法：鉄粉（粒径約１００μｍ）を接地した状態で、２３℃、６０％ＲＨ環境下にて一晩以上放置する。
【０１５６】
測定方法：測定は２３℃、６０％ＲＨ環境下で行う。先ず、上記で作製したサンプル板を図８に示す表面帯電量測定装置ＴＳ−１００ＡＳ（東芝ケミカル（株）製）にセットし、電位計８５を接地して値を０にする。上記で調湿した鉄粉８１を滴下器８２に入れ、ＳＴＡＲＴスイッチを押して２０秒間鉄粉８１をサンプル板８３上に滴下し、予め接地を施した受容器８４で受ける。この時の電位計８５の示す極性を読み取って、鉄粉に対する結着樹脂の帯電極性とした。尚、８６はコンデンサーである。
【０１５７】
（２）樹脂被覆層の形成に使用される結着樹脂の重量平均分子量
測定は、ＴＨＦを展開溶媒としたＧＰＣにて以下の条件で測定した。
測定装置：ＨＬＣ８１２０ＧＰＣ
測定条件：測定温度４０℃、流量０．６ｍｌ／分、サンプル注入量２０μｌ、サンプル濃度０．５％
検出器：屈折率計
カラム条件：ＴＳＫｇｅｌ Ｓｕｐｅｒ２０００
ＴＳＫｇｅｌ Ｓｕｐｅｒ３０００
ＴＳＫｇｅｌ Ｓｕｐｅｒ４０００
ＴＳＫｇｅｌ Ｓｕｐｅｒ５０００
ＴＳＫｇｅｌ Ｓｕｐｅｒ６０００
ＴＳＫ Ｇｕａｒｄ Ｃｏｌｕｍ Ｈ−Ｈを連結した。
【０１５８】
（３）黒鉛化粒子の黒鉛化度ｐ（００２）
黒鉛化度ｐ（００２）は、マックサイエンス社製の強力型全自動Ｘ線回折装置「ＭＸＰ１８」システムにより、黒鉛のＸ線回折スペクトルから得られる格子間隔ｄ（００２）を測定することで、ｄ（００２）＝３．４４０−０．０８６（１−ｐ²）で求めた。
【０１５９】
尚、格子間隔ｄ（００２）は、ＣｕＫαをＸ線源とし、ＣｕＫβ線はニッケルフィルターにより除去している。標準物質に高純度シリコンを使用し、Ｃ（００２）及びＳｉ（１１１）回折パターンのピーク位置から算出した。主な測定条件は以下のとおりである。
Ｘ線発生装置：１８ｋＷ
ゴニオメータ：横型ゴニオメータ
モノクロメータ：使用
管電圧：３０．０ｋＶ
管電流：１０．０ｍＡ
測定法：連続法
スキャン軸：２θ／θ
サンプリング間隔：０．０２０ｄｅｇ
スキャン速度：６．０００ｄｅｇ／ｍｉｎ
発散スリット：０．５０ｄｅｇ
散乱スリット：０．５０ｄｅｇ
受光スリット：０．３０ｍｍ
【０１６０】
（４）トナー及び樹脂粒子の粒径測定
測定装置としては、コールターカウンターＴＡ−ＩＩ型、或いはコールターマルチサイザーＩＩまたはコールターマルチサイザーＩＩＩ（いずれもべックマン・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、約１％ＮａＣｌ水溶液を調製する。例えば、ＩＳＯＴＯＮ−ＩＩ（べックマン・コールター社製）が使用できる。測定方法としては、前記電解水溶液１００ｍｌ〜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ホン酸塩を、０．１ｍｌ〜５ｍｌ加え、さらに測定試料を２ｍｇ〜２０ｍｇ加える。試料を懸濁した電解液は、超音波分散器で約１分〜３分間分散処理を行ない、前記測定装置により、アパーチャーとして１００μｍアパーチャー或いは３０μｍアパーチャーを用いて、測定試料の体積、個数を測定して体積分布と個数分布とを算出した。この結果より、体積分布から求めた重量基準の重量平均粒径（Ｄ４）及び個数分布から求めた個数基準の長さ平均粒径（Ｄ１）（共に各チャンネルの中央値をチャンネル毎の代表値とする）を求めた。
【０１６１】
（５）１μｍ以上の導電性粒子の粒径測定
黒鉛化粒子等の導電性粒子の粒径はレーザー回折型粒度分布計のコールターＬＳ−１３０型或いはＬＳ−２３０型粒度分布計（ベックマン・コールター社製）を用いて測定した。測定方法としては、水系モジュールを用い、測定溶媒としては純水を使用する。純水にて粒度分布計の測定系内を約５分間洗浄し、消泡剤として測定系内に亜硫酸ナトリウムを１０ｍｇ〜２５ｍｇ加えて、バックグラウンドファンクションを実行した。
【０１６２】
次に純水１０ｍｌ中に界面活性剤３滴〜４滴を加え、さらに測定試料を５ｍｇ〜２５ｍｇ加えた。試料を懸濁した水溶液は超音波分散器で１分間〜３分間分散処理を行なって試料液とし、前記測定装置の測定系内に試料液を徐々に加えて、装置の画面上のＰＩＤＳが４５％〜５５％になるように測定系内の試料濃度を調整して測定を行い、個数分布から算術した個数平均粒径を求めた。
【０１６３】
（６）１μｍ未満の導電性微粒子の粒径測定
電子顕微鏡を用いて、導電性微粒子の粒径を測定した。撮影倍率は６万倍にしたが、難しい場合は低倍率で撮影した後に６万倍となるように写真を拡大プリントした。写真上で１次粒子の粒径を測る。この際、長軸と短軸を測り、平均した値を粒径とする。これを、１００サンプルについて測定し、５０％値をもって平均粒径とした。
【０１６４】
（７）現像剤担持体表面の中心線平均粗さ（Ｒａ）の測定
ＪＩＳ Ｂ０６０１（２００１）の表面粗さに基づき、小坂研究所製表面粗度計ＳＥ−３４００にて、軸方向３点×周方向３点＝９点について各々測定し、その平均値をとった。測定条件としては、カットオフ０．８ｍｍ、測定距離８．０ｍｍ、送り速度０．１ｍｍ／ｓｅｃにて行なった。
【０１６５】
（８）樹脂被覆層の体積抵抗の測定
１００μｍの厚さのＰＥＴシート上に７μｍ〜２０μｍの厚さの樹脂被覆層を形成し、ＡＳＴＭ規格（Ｄ−９９１−８２）及び日本ゴム協会標準規格ＳＲＩＳ（２３０１−１９６９）に準拠した、導電性ゴム及びプラスチックの体積抵抗測定用の４端子構造の電極を設けた電圧降下式デジタルオーム計（川口電機製作所製）を使用して測定した。尚、測定環境は２０℃〜２５℃、５０％ＲＨ〜６０％ＲＨとした。
【０１６６】
（９）粒子の体積抵抗の測定
粒状試料を４０ｍｍφのアルミリングに入れ、２５００Ｎで加圧成型し、抵抗率計ロレスタＡＰ、またはハイレスタＩＰ（共に、三菱油化製）にて４端子プローブを用いて体積抵抗値を測定した。尚、測定環境は、２０℃〜２５℃、５０％ＲＨ〜６０％ＲＨとした。
【０１６７】
（１０）球状粒子の真密度の測定
本発明で使用する球状粒子の真密度は、乾式密度計アキュピック１３３０（島津製作所製）を用いて測定した。
【０１６８】
（１１）樹脂被覆層の膜厚（削れ量）の測定
被覆層の削れ量（膜削れ）の測定としてはＫＥＹＥＮＣＥ社製レーザー寸法測定器を用いた。コントローラＬＳ−５５００及びセンサーヘッドＬＳ−５４０Ｔを用い、スリーブ固定治具及びスリーブ送り機構を取り付けた装置にセンサー部を別途固定し、スリーブの外径寸法の平均値から測定を行った。測定はスリーブ長手方向に対し３０分割して３０箇所測定し、さらにスリーブを周方向に９０°回転させた後さらに３０箇所、計６０箇所の測定を行い、その平均値をとった。表面被覆層形成前のスリーブの外径を予め測定しておき、表面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及び削れ量とした。
【０１６９】
以下に本発明の実施態様を示す。
【０１７０】
〔実施態様１〕
潜像担持体上に形成された潜像を、現像剤担持体表面に搬送担持された現像剤により現像し可視化するための現像装置に用いられる現像剤担持体であって、
円筒状もしくは円柱状の金属基体表面に樹脂被覆層を有し、該樹脂被覆層が、正帯電性樹脂及びメソカーボンマイクロビーズ粒子またはバルクメソフェーズピッチ粒子を焼成して得られた黒鉛化粒子を少なくとも含有していることを特徴とする現像剤担持体。
【０１７１】
〔実施態様２〕
現像剤を収容するための現像容器、該現像容器に収容されている現像剤を担持し、現像領域に搬送するための現像剤担持体、及び該現像剤担持体上に担持される現像剤の層厚を規制するための現像剤層厚規制部材を少なくとも有する現像装置であって、上記現像剤担持体が、実施態様１の現像剤担持体であることを特徴とする現像装置。
【０１７２】
〔実施態様３〕
潜像担持体上に形成された静電潜像を現像剤によって現像剤像として可視化し、可視化された現像剤像を転写材に転写することにより画像形成をするための、画像形成装置本体に対して着脱可能に装着されるプロセスカートリッジであって、
静電潜像を担持するための潜像担持体と、該潜像担持体を帯電するための帯電手段と、該記潜像担持体に形成された静電潜像を、現像剤を用いて現像を行なうことにより現像剤像として可視化するとともに、該現像剤像が記録媒体たる転写材に転写された後に、前記潜像担持体上に残留した現像剤を回収するための現像手段とを少なくとも有し、該現像手段は、現像剤を収容する現像剤容器、及び該現像剤容器内に収容されている現像剤を担持し、且つ該現像剤を現像領域へ搬送するための現像剤担持体を有し、前記潜像担持体及び現像手段が一体化され、該現像剤担持体が、実施態様１の現像剤担持体であることを特徴とするプロセスカートリッジ。
【０１７３】
〔実施態様４〕
実施態様１〜３のいずれかにおいて、正帯電性樹脂がアミノ樹脂である。
【０１７４】
〔実施態様５〕
実施態様４において、アミノ樹脂がメラミン系樹脂、グアナミン系樹脂、アニリン系樹脂または尿素樹脂である。
【０１７５】
〔実施態様６〕
実施態様１〜５のいずれかにおいて、黒鉛化粒子の黒鉛化度ｐ（００２）が、０．２０≦ｐ（００２）≦０．９５である。
【０１７６】
〔実施態様７〕
実施態様１〜６のいずれかにおいて、黒鉛化粒子の個数平均粒径が０．５μｍ〜２５μｍである。
【０１７７】
【実施例】
次に、具体的実施例をもって、本発明をさらに詳しく説明するが、本発明は何らこれらに限定されるものではない。尚、以下の配合における「部」及び「％」は、特にことわらない限りすべて「質量部」及び「質量％」である。
【０１７８】
〔現像剤担持体の製造例１〕
樹脂被覆層を形成するための樹脂として、表１に挙げたメチルエーテル化メラミン樹脂（Ａ−１）とビスフェノール型ポリエステル樹脂（Ａ−８）を選択した。先ず、Ａ−１：３０部とＡ−８：７０部、及びメタノール２２０部（樹脂溶液中のメタノール込み）をφ２ｍｍのガラス粒子にて１時間サンドミル分散を行ない、その後ガラス粒子を篩いで分離し、この樹脂溶液を、ＳＵＳ板上にバーコーター（＃６０）にて塗布し、これを１５０℃／３０分で加熱・硬化させ、サンプル板を作製した。このサンプル板を接地した状態で、２３℃、６０％ＲＨ環境下にて一晩放置させた。これを前述した方法によって鉄粉との摩擦帯電極性を測定したところ、正帯電性を示した。なお、表１に挙げた各々の樹脂（単独）の帯電極性も、上記と同様の方法によって測定した結果を記載した。
【０１７９】
次に、黒鉛化粒子として、メソカーボンマイクロビーズ粒子を酸化性雰囲気下で熱安定化処理した後に２８００℃で焼成することにより黒鉛化して得た個数平均径５．５μｍの黒鉛化粒子Ｂ−１を用いた。黒鉛化粒子Ｂ−１の物性は表２に示した。さらに、表３には樹脂被覆層に凹凸を付与するための粒子の物性を記載した。
【０１８０】
樹脂Ａ−１（メタノール５０％含有溶液） ６０部
樹脂Ａ−８（メタノール５０％含有溶液） １４０部
黒鉛化粒子Ｂ−１ ３６部
導電性カーボンブラック ４部
凹凸形成粒子Ｃ−１ １２部
メタノール １２０部
上記材料に直径１ｍｍのガラスビーズをメディア粒子として加え、サンドミルにて２時間分散し、フルイを用いてビーズを分離し、メタノールで固形分を３５％に調整し塗工液を得た。この塗工液を用い、外径２０ｍｍφ、中心線平均粗さＲａ＝０．２μｍの研削加工したアルミニウム製円筒管を垂直に立て、一定速度で回転させるとともに、上下端部にマスキングを施し、スプレーガンを一定速度で下降させながら塗布することによって樹脂被覆層を形成させた。続いて熱風乾燥炉により１５０℃、３０分間加熱して樹脂被覆層を硬化させ現像剤担持体（現像スリーブ）Ｓ−１を作成した。表４に該現像剤担持体Ｓ−１の樹脂被覆層の処方と物性を挙げた。
【０１８１】
〔現像剤担持体の製造例２〜１０及び比較製造例１〜７〕
表４に記載した処方により、現像剤担持体の製造例１と同様にしてメタノールにて固形分を３５％に調整した塗工液を作成した後、表面に樹脂被覆層を有する現像剤担持体Ｓ−２〜Ｓ−１７を製造した。尚、樹脂層の帯電極性に関しても現像剤担持体の製造例１と同様に、樹脂以外の成分を除いた溶液を作成し、ＳＵＳ板上にバーコーターした後に鉄粉との摩擦帯電極性を測定した。
【０１８２】
【表１】

【０１８３】
【表２】

【０１８４】
【表３】

【０１８５】
【表４】

【０１８６】
〔現像剤の製造例１〕
スチレン ６８．５部
アクリル酸２−エチルヘキシル ２０部
マレイン酸モノブチル １０部
ジビニルベンゼン １．５部
ベンゾイルパーオキサイド １部
ジ−ｔｅｒｔ−ブチルパーオキシ−２−エチルヘキサノエート ０．５部
上記混合物にポリビニルアルコール部分ケン化物０．８部を溶解した水２００部を加え、激しく攪拌させて懸濁分散液とした。さらに、水５０部を加え、窒素置換した反応器に上記懸濁分散液を添加し、反応温度８０℃にて９時間懸濁重合反応させた。反応終了後、水洗し、脱水、乾燥工程を経て、ビニル系樹脂（１）を得た。
【０１８７】
上記ビニル系樹脂（１） １００部
マグネタイト ９０部
アゾ系鉄錯体化合物（負帯電性荷電制御剤） ２部
低分子量エチレン−プロピレン共重合体 ３部
上記混合物を１３０℃に加熱した２軸混練押し出し機にて混練した。得られた混練物を冷却した後、ハンマーミルで粗粉砕し、該粗粉砕物をジェット気流を用いた微粉砕機を用いて微粉砕し、得られた微粉砕粉をコアンダ効果を利用した多分割分級装置で、超微粉及び粗粉を同時に分級除去して、重量平均粒径（Ｄ４）が７．３μｍのトナー粒子を得た。
【０１８８】
このトナー粒子１００部に対し、ヘキサメチルジシラザン及びジメチルシリコーンオイル処理を施した負帯電性疎水性シリカ微粉末（ＢＥＴ比表面積：３００ｍ²／ｇ）を１．５部、チタン酸ストロンチウム４．５部を加え、ヘンシェルミキサーにて混合し、本発明に使用する一成分系負帯電性磁性現像剤（トナー１）を得た。
【０１８９】
〔実施例１〕
前述の現像剤担持体Ｓ−１にマグネットローラを挿入し、両端にフランジを取り付けた。この現像剤担持体Ｓ−１を、静電潜像担持体としてＯＰＣドラムを使用したキヤノン製デジタル複写機ＩＲ２０００（２３０Ｖ機仕様）の現像器に組み込み、上記トナー１を用いて１枚／１０秒の間欠モードで５万枚画出しを行った。画像評価は、常温常湿度環境（２３℃、５０％ＲＨ；Ｎ／Ｎ）、低温低湿度環境（１５℃、１０％ＲＨ；Ｌ／Ｌ）及び高温高湿度環境（３２℃、８５％ＲＨ；Ｈ／Ｈ）において実施した。尚、現像装置の概略は、図６に挙げたようなものであり、現像剤層厚規制部材としては、ウレタンゴムからなる弾性ブレードを使用した。画像評価の結果は表５に挙げたように、いずれの環境下においても終始良好な現像性を得ることができた。評価方法及び評価基準は以下の通りである。
【０１９０】
（１）画像濃度
画像比率５．５％であるテストチャート上の５ｍｍφ丸部のコピー画像濃度を、反射濃度計ＲＤ９１８（マクベス製）により反射濃度測定を行い、１０点の平均値をとって画像濃度とした。
【０１９１】
（２）カブリ
適正画像におけるベタ白画像の反射率を測定し、さらに未使用の転写紙の反射率を測定し、（ベタ白画像の反射率の最悪値−未使用転写紙の反射率の平均値）をカブリ濃度とし、評価結果を下記の指標にて示した。（但し、反射率の測定はランダムに１０点の測定を行なった。）反射率はＴＣ−６ＤＳ（東京電色製）によって測定を行なった。
Ａ：１．０％以下（目視ではカブリは認められない）
Ｂ：１．０〜２．０％（注視しなければカブリは認められない）
Ｃ：２．０〜３．０％（カブリはあるものの実用上問題なし）
Ｄ：３．０％以上（カブリが目立ちＮＧレベル）
【０１９２】
（３）スリーブゴースト
ベタ白部とベタ黒部が隣り合う画像を現像した現像スリーブの位置が、現像スリーブの次の回転時には現像位置に来て、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に基づいて評価した。
Ａ：濃淡差が全く見られない。
Ｂ：軽微な濃淡差が見られる。
Ｃ：濃淡差がやや見られるが実用可。
Ｄ：実用上問題となる濃淡差がスリーブ１周分以上出る。
【０１９３】
（４）ブロッチ（画像不良）
ベタ黒、ハーフトーン、ライン画像等の各種画像及び、その際、現像スリーブ上の波状ムラ、及びブロッチ（斑点状ムラ）等、スリーブ上でのトナーコート不良の目視による観察を参考にして、評価結果を下記の基準に基づいて評価した。
Ａ：画像にもスリーブ上にも全く確認できない。
Ｂ：スリーブ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。
Ｃ：ハーフトーン画像またはベタ黒画像で確認できるが実用可。
Ｄ：ベタ黒画像全体で実用上問題となる画像不良が確認できる。
Ｅ：ベタ白画像上にも実用上問題となる画像不良が確認できる。
【０１９４】
（５）ハーフトーン均一性（白スジ、白帯）
特にハーフトーンに発生する、画像進行方向に走る、線状、帯状のスジについて、下記基準にて評価した。
Ａ：画像にもスリーブ上にも全く確認できない。
Ｂ：ハーフトーンでは確認できるが、ベタ黒では問題ないレベル。
Ｃ：ベタ黒画像でも濃淡差が確認できるが、実用可
Ｄ：ベタ黒画像全体で実用上問題となる濃淡差が目立つ。
Ｅ：濃度が低く、スジの非常に多い画像。
【０１９５】
（６）画質
Ａ：倍率が１０倍のルーペで見ても飛び散りのない鮮明な画像である。
Ｂ：目視で見る限り鮮明な画像である。
Ｃ：若干飛び散りが見られるものの実用上問題ない。
Ｄ：飛び散り以外に文字のカスレが目立つ。
【０１９６】
（７）樹脂被覆層の耐摩耗性
耐久前後の現像剤担持体表面の中心線平均粗さ（Ｒａ）と樹脂被服層の膜厚の削れ量を測定した。
【０１９７】
（８）樹脂被覆層の耐汚染性
耐久後の現像剤担持体表面をＫＥＹＥＮＣＥ社製の超深度形状測定顕微鏡を用いて、約２００倍で観察し、トナー汚染の程度を下記の基準に基づいて評価した。
Ａ：軽微な汚染しか観察されない。
Ｂ：やや汚染が観察される。
Ｃ：部分的に汚染が観察される。
Ｄ：著しい汚染が観察される。
【０１９８】
〔実施例２〜１０及び比較例１〜７〕
現像剤担持体Ｓ−１〜Ｓ−１７を用い、実施例１と同様の評価方法にて、画像評価を行なった。結果は表５、表６に挙げた。
【０１９９】
【表５】

【０２００】
【表６】

【０２０１】
〔現像剤担持体の製造例１１〜１５及び比較製造例８〜１０〕
表７に記載した処方により、現像剤担持体の製造例１と同様にしてメタノールにて固形分を３５％に調整した塗工液を作成した後、表面に樹脂被覆層を有する現像剤担持体Ｓ−１８〜Ｓ−２５を製造した。但し、スリーブ素管としては、外径２４．５ｍｍφ、中心線平均粗さＲａ＝０．３μｍの研削加工したアルミニウム製円筒管を用いた。尚、樹脂層の帯電極性に関しても現像剤担持体（現像スリーブ）の製造例１と同様に、樹脂以外の成分を除いた溶液を作成し、ＳＵＳ板上にバーコーターした後に鉄粉との摩擦帯電極性を測定した。
【０２０２】
〔現像剤の製造例２〕
エチレンオキサイド付加ビスフェノールＡ ３３モル％
プロピレンオキサイド付加ビスフェノールＡ ２４モル％
テレフタル酸 ２６モル％
ｎ−ドデセニルコハク酸 １２モル％
トリメリット酸 ５モル％
上記原料を５リットル４口フラスコに仕込み、還流冷却器、水分離装置、Ｎ₂ガス導入管、温度計及び撹拌装置を付し、フラスコ内にＮ₂ガスを導入しながら１８０℃で縮合重合反応を行い、反応終了後、水洗し、脱水、乾燥工程を経て、ポリエステル樹脂（２）を得た。
【０２０３】
上記ポリエステル系樹脂（２） １００部
マグネタイト ９０部
アゾ系鉄錯体化合物（負帯電性荷電制御剤） ２部
フィッシャートロプシュワックス ５部
上記材料を用い、現像剤の製造例１と同様の方法にて重量平均粒径（Ｄ４）が６．３μｍのトナー粒子を得た。
【０２０４】
このトナー粒子１００部に対し、ヘキサメチルジシラザンで処理を施した負帯電性疎水性シリカ微粉末（ＢＥＴ比表面積：３００ｍ²／ｇ）を１．２部、チタン酸ストロンチウム４．０部を加え、ヘンシェルミキサーにて混合し、本発明に使用する一成分系負帯電性磁性現像剤（トナー２）を得た。
【０２０５】
〔実施例１１〜１５及び比較例８〜１０〕
前述の現像剤担持体Ｓ−１８〜Ｓ−２５にマグネットローラを挿入し、両端にフランジを取り付けた。この現像剤担持体を、静電潜像担持体としてアモルファスシリコンドラムを使用したキヤノン製デジタル複写機ＩＲ６０００の現像器に組み込み、上記トナー２を用いて連続モードで１０万枚画出しを行った。画像評価は、常温常湿度環境（２３℃、５０％ＲＨ；Ｎ／Ｎ）、低温低湿度環境（１５℃、１０％ＲＨ；Ｌ／Ｌ）及び高温高湿度環境（３２℃、８５％ＲＨ；Ｈ／Ｈ）において実施した。尚、現像装置の概略は、図５に挙げたようなものであり、現像剤層厚規制部材としては、磁性ブレードを使用した。画像評価の結果は表８に挙げた。
【０２０６】
〔現像剤担持体の製造例１６〜２０及び比較製造例１１〜１３〕
表７に記載した処方により、現像剤担持体の製造例１と同様にしてメタノールにて固形分を３５％に調整した塗工液を作成した後、表面に樹脂被覆層を有する現像剤担持体Ｓ−２６〜Ｓ−３３を製造した。但し、スリーブ素管としては、外径１６ｍｍφ、中心線平均粗さＲａ＝０．２μｍの研削加工したアルミニウム製円筒管を用いた。尚、樹脂層の帯電極性に関しても現像剤担持体（現像スリーブ）の製造例１と同様に、樹脂以外の成分を除いた溶液を作成し、ＳＵＳ板上にバーコーターした後に鉄粉との摩擦帯電極性を測定した。
【０２０７】
〔現像剤の製造例３〕
高速撹拌装置ＴＫ−ホモミキサーを備えた２リットル用四つ口フラスコ中に、イオン交換水８８０部と０．１モル／リットル−Ｎａ₃ＰＯ₄水溶液４５０部を添加し、回転数を１２０００ｒｐｍに調整し、５８℃に加温せしめた。ここに１．０モル／リットル−ＣａＣｌ₂水溶液６８部を徐々に添加し、微小な難水溶性分散剤Ｃａ₃（ＰＯ₄）₂を含む分散媒系を調製した。
【０２０８】
一方、分散質系は、
スチレンモノマー １７０部
ｎ−ブチルアクリレートモノマー ４０部
Ｃ．Ｉ．ピグメンブルー１５：３ １４部
飽和ポリエステル樹脂 １６部
（テレフタル酸とエチレンオキサイド付加ビスフェノールＡをモル比で５５０で混合し、縮重合して得られたもの）
ジ−ｔｅｒｔ−ブチルサリチル酸クロム化合物（負帯電性荷電制御剤） ２部
エステル系ワックス ２０部
上記混合物をアトライターを用い３時間分散させた後、重合開始剤である２，２’−アゾビス（２，４−ジメチルバレロニトリル）１０部を添加し分散物を得た。これを上記分散媒中に投入し回転数を維持しつつ１２分間造粒した。その後高速撹拌器からプロペラ撹拌羽根に撹拌器を変え、内温を８０℃に昇温させ５０ｒｐｍで重合を１０時間継続させた。重合終了後スラリーを冷却し、希塩酸を添加し分散剤を除去せしめた。さらに洗浄及び乾燥してシアントナー粒子を得た。該シアントナーの重量平均粒径（Ｄ４）は７．３μｍであった。このトナー粒子１００部に対し、ヘキサメチルジシラザン処理を施した負帯電性疎水性シリカ微粉末（ＢＥＴ比表面積：３００ｍ²／ｇ）を１．３部、チタン酸ストロンチウム０．５部を加え、ヘンシェルミキサーにて混合した。該現像剤をトナー３とする。
【０２０９】
〔実施例１６〜２０及び比較例１１〜１３〕
現像剤担持体Ｓ−２６〜Ｓ−３３を、静電潜像担持体としてＯＰＣドラムを使用したキヤノン製カラーレーザービームプリンターＬＢＰ２０３０改造機のシアントナー用現像器に組み込み、上記トナー３を用いて連続モードで３万枚画出しを行った。画像評価は、常温常湿度環境（２３℃、５０％ＲＨ；Ｎ／Ｎ）、低温低湿度環境（１５℃、１０％ＲＨ；Ｌ／Ｌ）及び高温高湿度環境（３２℃、８５％ＲＨ；Ｈ／Ｈ）において実施した。尚、現像装置の概略は、図６に挙げたようなものを非磁性現像剤用に改造したものであり、現像剤層厚規制部材としては、リン青銅薄板上にショアーＤ硬度４０度のポリアミドポリエーテルエラストマーを射出成形にて設けて改造した弾性規制部材を用いた。画像評価の結果は表９に挙げた。
【０２１０】
【表７】

【０２１１】
【表８】

【０２１２】
【表９】

【０２１３】
【発明の効果】
以上詳細に説明したように、本発明によれば、いかなる環境下においても、濃度低下、画像濃度ムラ、スリーブゴースト及びカブリの如き問題点が発生せず、均一で濃度ムラが無く、画像濃度が高い高精細な画像を安定して得ることのできる現像剤担持体、現像装置及びプロセスカートリッジを提供することが可能になる。
【０２１４】
また本発明によって、粒径の小さいトナーや球形のトナーを用いた場合等に見られる、現像剤担持体表面へのトナー付着を軽減させることにとり、トナーの不均一な帯電を制御すると共にトナーに十分な帯電を与えることのできる現像剤担持体、現像装置及びプロセスカートリッジを提供することが可能になる。
【０２１５】
さらに本発明によって、長期にわたる耐久による現像剤担持体表面の樹脂被覆層の劣化が生じ難く、高耐久性を有し、終始安定した画質が得られる現像剤担持体、現像装置及びプロセスカートリッジを提供することが可能になる。
【０２１６】
またさらに、本発明によって、長期間にわたる連続複写においても現像剤担持体上の現像剤に高くて均一な帯電を付与するとともに、チャージアップ現象の発生もなく安定した電荷を常時付与することで、耐久中の画像濃度低下や均一で濃度ムラやカブリのない高品位の画像を得ることのできる現像剤担持体、現像装置及びプロセスカートリッジを提供することが可能になる。
【図面の簡単な説明】
【図１】本発明の現像剤担持体の一実施形態の部分断面を示す模式図である。
【図２】本発明の現像剤担持体の一実施形態の部分断面を示す模式図である。
【図３】本発明の現像剤担持体の一実施形態の部分断面を示す模式図である。
【図４】本発明の現像剤担持体の一実施形態の部分断面を示す模式図である。
【図５】本発明の現像装置の一実施形態の概略的説明図である。
【図６】本発明の現像装置の一実施形態の概略的説明図である。
【図７】本発明のプロセスカートリッジの一実施形態の概略説明図である。
【図８】本発明の現像剤担持体の樹脂被覆層を形成する結着樹脂の帯電極性を測定するための表面帯電量測定装置の概略的説明図である。
【符号の説明】
１ 樹脂被覆層
２ 基体
３ マグネットローラ
１１ 黒鉛化粒子
１２ 結着樹脂
１３ 導電剤
１４ 固体潤滑剤
１５ 球状粒子
５１ 感光ドラム
５２ 磁性規制ブレード
５３ 現像容器
５４ 仕切部材
５５ 攪拌搬送部材
５６ 金属円筒管
５７ 樹脂被覆層
５８ 現像スリーブ（現像剤担持体）
５９ 磁石
６０ 現像ローラー
６１ 攪拌部
６２ 現像剤供給部材
６３ 現像バイアス電源
６４ 第一室
６５ 第二室
６７ 弾性規制ブレード
７０ プロセスカートリッジ
７１ 現像手段
７２ クリーニング手段
７２ａ クリーニングブレード
７３ 接触帯電手段
８１ 鉄粉
８２ 滴下器
８３ サンプル
８４ 受容器
８５ 電位計
８６ コンデンサー[0001]
BACKGROUND OF THE INVENTION
The present invention develops and visualizes a latent image formed on an electrostatic latent image carrier in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet recording method, or the like. The present invention relates to a developer carrying member used in a developing device, a developing device using the developer carrying member, and a process cartridge.
[0002]
[Prior art]
As conventional electrophotographic methods, various methods are described in Patent Documents 1, 2 (3), 4 (5), etc., but generally, a photoconductive substance is used and electrostatic latent is obtained by various means. An electrostatic latent image is formed on an image carrier (photoconductor), and then the electrostatic latent image is developed using a developer (toner), and the toner image is transferred to a transfer material such as paper as necessary. Thereafter, the image is fixed by heating, pressure, solvent vapor or the like to obtain a copy.
[0003]
In recent years, there are a large number of devices using electrophotography such as printers and facsimiles in addition to conventional copying machines. The development methods are roughly classified into a two-component development method using carrier particles and a one-component development method using no carrier particles. The one-component development method includes a one-component magnetic development method in which magnetic particles are encapsulated in toner and the developer is carried and conveyed by the action of magnetic force, and the developer is caused by the action of the triboelectric charge of the developer without using magnetic particles. There is a one-component non-magnetic development system in which a developer is carried on a developer carrier. In the one-component magnetic development method, a colorant such as carbon black is not used, and magnetic particles can also be used as a colorant.
[0004]
The two-component development method requires carrier particles such as glass beads and iron powder, or the toner concentration in the developer must be kept constant. Therefore, the developing device is large, heavy, and has a complicated configuration. Further, in the two-component development method, the toner component is likely to adhere to the carrier (spent), and therefore the carrier replacement frequency increases. In this one-component development method, such a carrier and the above-described complicated configuration are unnecessary, the developing device itself can be reduced in size and weight, and further, since the carrier does not need to be replaced, maintenance can be performed for a long time. There is no need. On the other hand, since the one-component magnetic development method uses dark black magnetic particles for the toner, it is difficult to colorize the two-component development method, and the two-component development method can adjust the fine development state with a density detection device. It is preferably used for color development. In recent years, there has been a demand for reducing the size of a copying apparatus for the purpose of reducing the weight and size of an electrophotographic apparatus. For this reason, a developing apparatus using a one-component developing system has been increasingly used. .
[0005]
However, when such a one-component development method is used, it is difficult to adjust the toner charge amount, and various contrivances with the toner have been made, but problems related to toner non-uniformity and charge durability stability are, It is not fully resolved.
[0006]
In particular, while the developer carrying member (developing sleeve) is repeatedly rotated, the charge amount of the toner coated on the developing sleeve becomes too high due to contact with the developing sleeve, and the toner is mirrored with the surface of the developing sleeve. The so-called charge-up phenomenon that is attracted by the imaging force and becomes immobile on the surface of the developing sleeve and does not move from the developing sleeve to the latent image on the latent image carrier (photosensitive drum) is likely to occur particularly in a low humidity environment. . When such a charge-up phenomenon occurs, the toner in the upper layer becomes difficult to be charged, and the development amount of the toner is reduced, which causes problems such as thin line images and thin image density of solid images. Furthermore, a so-called blotch phenomenon occurs in which toner that is not properly charged due to charge-up becomes poorly regulated and flows out onto the developing sleeve, causing spots and irregularities on the waves. Furthermore, since the toner layer formation state of the image part (toner consumption part) and the non-image part (toner non-consumption part) changes and the charging state changes, for example, a position where a solid image having a high image density is once developed. However, when the halftone image is developed when the developing sleeve is rotated at the next rotation, a so-called sleeve ghost phenomenon that a solid image appears on the image is likely to occur.
[0007]
Recently, LED (light-emitting diode) printers and LBP (laser beam printers) have become mainstream in the market, and the direction of technology is higher resolution, that is, the conventional 300 dpi, 400 dpi, 600 dpi, 800 dpi, It has become 1200 dpi. Accordingly, the development method is also required to have higher definition. Also, digitalization of copiers has become the mainstream, and designs aiming at so-called multi-functions that can be used simultaneously as facsimiles and printers are becoming main. For this reason, the difference between a copying machine and a printer is gradually disappearing, and a high-resolution and high-definition developing method is also required here. For example, Patent Documents 6 and 7 propose toners having a small particle size, and as high resolution is required, toner particles having a central particle size of about 5 μm to 9 μm are mainstream. .
[0008]
Further, from the viewpoint of ecology and for the purpose of further reducing the weight and size of the apparatus, the toner transfer efficiency is improved in order to reduce waste toner. For example, a transfer efficiency improver having an average particle size of 0.1 μm to 3 μm and a BET specific surface area of 50 m²/ G-300m²/ G of hydrophobic silica fine powder reduces the volume resistance of the toner, improves the transfer efficiency by forming a thin film layer of the transfer efficiency improver on the photosensitive drum, and further reduces the toner itself. A method of improving the transfer efficiency by performing a spheroidizing process by a mechanical impact force is known. Also, the set temperature of the fixing device tends to be lowered for the purpose of shortening the first copy time and saving power. Under such circumstances, toner in particular under low temperature and low humidity increases the amount of charge per unit mass, and thus becomes more likely to adhere electrostatically onto the developing sleeve. Toner under high temperature and high humidity is physically exposed from the outside. As a result of using a material that is easy to fluidize and fluidize, it is easy to change its quality, and the toner is easily contaminated with the sleeve and the sleeve is fused.
[0009]
As a developer carrying member (developing sleeve) used in the above-described development, for example, a metal, an alloy thereof or a compound thereof is molded into a cylindrical shape, and the surface thereof is made to have a predetermined surface roughness by electrolysis, blasting, file processing or the like What was processed in this way has been used conventionally. However, in this case, the developer present in the vicinity of the surface of the developer carrier in the developer layer formed on the surface of the developer carrier by the regulating member has a very high charge, and is reflected on the surface of the developer carrier. The developer is strongly attracted by the force, so that it is not possible to have a chance of friction between the toner and the developer carrying member, so that the developer cannot hold a suitable charge. Under such circumstances, sufficient development and transfer are not performed, and the obtained image has many density unevenness and character scattering.
[0010]
Resin in which a conductive material such as carbon or crystalline graphite or a solid lubricant such as graphite is dispersed in the resin in order to prevent the occurrence of such an excessively charged developer and the strong adhesion of the developer. Patent Documents 8 to 12 propose a method for forming a coating layer on the developer carrier.
[0011]
When such a resin coating layer in which crystalline graphite is dispersed is used, the surface of the resin coating layer has lubricity due to the scaly structure of crystalline graphite. However, the shape of the resin coating layer is non-uniform because of its flake shape, and the hardness of the crystalline graphite is low. Wear and detachment itself tends to occur, and when the durability is promoted, the surface roughness and surface composition of the resin coating layer change, and it is easy to cause poor toner conveyance and non-uniform charge application to the toner. Become.
[0012]
On the other hand, when the addition amount is small, the effect of the conductive fine powder such as crystalline graphite and carbon is thin, and there remains a problem that it is insufficient for charge-up and sleeve ghost.
[0013]
Patent Document 13 proposes a developing sleeve in which a conductive resin coating layer in which spherical fine particles are dispersed in a conductive fine powder such as crystalline graphite and carbon in a resin is provided on a metal substrate. In this developing sleeve, the wear resistance of the resin coating layer is improved to some extent, the shape of the surface of the resin coating layer is made uniform, and the change in surface roughness due to durability is relatively small, so the toner coating on the sleeve is stable. The charge of the toner can be made uniform, and there is a tendency to stabilize the image quality without problems such as sleeve ghost, image density, and image density unevenness. However, this developing sleeve is also insufficient for abrasion resistance, uniform charging to the toner, and stabilization of the ability to impart charge to the toner, and for further long-term durability, the spherical shape dispersed in the resin coating layer is insufficient. In such cases, changes in the surface roughness or unevenness of the surface of the resin coating layer caused by wear or drop of particles or crystalline graphite, resulting in toner contamination and toner fusion of the resin coating layer. In this case, the toner is unstablely charged, causing image defects.
[0014]
Alternatively, in Patent Document 14, the spherical particles dispersed in the conductive resin coating layer are low specific gravity and conductive spherical particles, whereby the conductive spherical particles are uniformly dispersed in the conductive resin coating layer. As a result, the wear resistance of the resin coating layer and the shape of the surface of the coating layer are made uniform to improve the uniform chargeability to the toner, and toner contamination and toner fusion are suppressed even when the resin coating layer is worn slightly. Possible developing sleeves have been proposed. However, this developing sleeve is not perfect in terms of wear resistance, uniform charging to the toner and ability to impart charge to the toner, and the conductive spherical particles on the surface of the resin coating layer are not suitable for further long-term durability. Conductive particles such as crystalline graphite are likely to be worn or dropped from the non-existing portion, and the wear of the resin coating layer is promoted from the worn and dropped portion, resulting in toner contamination and toner fusion, so that the toner is not charged. It becomes stable and causes image defects. Further, when this developing sleeve is used, the ability to impart high charge to the toner is also insufficient, and it is sufficient to obtain a high image density for a toner or the like that has deteriorated due to repeated frictional charging on the developing sleeve. In some cases, the charge amount cannot be applied.
[0015]
On the other hand, the approach from resin which comprises a resin coating layer is also carried out. For example, Patent Document 15 proposes a method for reducing the friction of the surface of the developing sleeve by coating the surface of the conductive elastic layer with a resin component different from that of the conductive elastic layer. However, according to this method, the ability to impart triboelectric charge to the toner is likely to be lowered, and as a result, the charge amount of the toner is lowered, and problems such as density reduction and fog deterioration are liable to occur on the image surface.
[0016]
Attempts have also been made to improve wear resistance by hardening the resin coating layer itself. For example, Patent Document 16 proposes a film in which a film containing melamine-modified phenolic resin and crystalline graphite is formed on the surface of the developing sleeve. In Patent Document 17, a film containing a melamine resin and / or urea resin containing graphite and / or carbon black is formed on the surface of the developing sleeve. Further, in Patent Document 18, a component having a molecular weight of 500 or less is 3.5% or less. A developing sleeve in which molybdenum disulfide is dispersed in a resin layer obtained by adding a melamine resin or a guanamine resin to an acrylic resin is disclosed. Melamine resins and guanamine resins have been used as crosslinking agents for thermosetting resins, and are effective in increasing the strength of the resin coating layer. Further, since they contain amino groups, they are particularly useful for negatively chargeable toners. It is expected to work effectively for charging. However, it is difficult to stabilize the chargeability, and the environment dependency is particularly noticeable, and it is likely to cause adverse effects such as charge-up of the toner in a low humidity environment and a decrease in the charge amount in a high humidity environment. . Furthermore, in terms of strength, for example, a developing device that employs a system that applies a large load to the developing sleeve such as an elastic blade as a member that regulates the toner layer thickness on the developing sleeve has high durability / long life. However, it is still insufficient.
[0017]
[Patent Document 1]
US Pat. No. 2,297,691
[Patent Document 2]
Japanese Patent Publication No.42-23910
[Patent Document 3]
US Pat. No. 3,666,363
[Patent Document 4]
Japanese Patent Publication No.43-24748
[Patent Document 5]
U.S. Pat. No. 4,071,361
[Patent Document 6]
Japanese Patent Laid-Open No. 01-112253
[Patent Document 7]
Japanese Patent Laid-Open No. 02-284158
[Patent Document 8]
JP-A-01-277265
[Patent Document 9]
Japanese Unexamined Patent Publication No. 03-036570
[Patent Document 10]
Japanese Patent Laid-Open No. 02-105181
[Patent Document 11]
JP 05-006089 A
[Patent Document 12]
Japanese Patent Laid-Open No. 05-066660
[Patent Document 13]
Japanese Patent Laid-Open No. 03-200986
[Patent Document 14]
Japanese Patent Laid-Open No. 08-240981
[Patent Document 15]
Japanese Patent Application Laid-Open No. 10-115979
[Patent Document 16]
JP-A-6-194940
[Patent Document 17]
JP-A-9-146362
[Patent Document 18]
Japanese Patent Laid-Open No. 9-230690
[0018]
[Problems to be solved by the invention]
The object of the present invention is to stabilize a high-definition image that is uniform, free of unevenness of density, and high in image density, without causing problems such as density reduction, image density unevenness, sleeve ghosting and fogging in any environment. Another object is to provide a developer carrying member, a developing device, and a process cartridge that can be obtained.
[0019]
A further object of the present invention is to control toner non-uniform charging by reducing toner adhesion to the surface of the developer carrying member, which is seen when using a toner having a small particle diameter or a spherical toner. It is an object of the present invention to provide a developer carrier, a developing device, and a process cartridge that can sufficiently charge toner.
[0020]
Another object of the present invention is to provide a developer carrying body, a developing device, and a process cartridge that are resistant to deterioration of the resin coating layer on the surface of the developer carrying body due to long-term durability, have high durability, and provide a stable image quality throughout. Is to provide.
[0021]
Another object of the present invention is to provide a high and uniform charge to the developer on the developer carrying member even during continuous copying over a long period of time, and always to provide a stable charge without the occurrence of a charge-up phenomenon. Accordingly, it is an object of the present invention to provide a developer carrying member, a developing device, and a process cartridge that can obtain a high-quality image that has a reduced image density and is uniform and free from unevenness in density and fogging.
[0022]
[Means for solving the problems]
  The above problem can be achieved by the following configuration. That is,
(1) The latent image formed on the latent image carrier is developed and visualized with a one-component negatively charged magnetic developer or a one-component negatively charged nonmagnetic developer conveyed and supported on the surface of the developer carrier. A developer carrying member used in a developing device for
  It has a resin coating layer on the surface of a cylindrical or columnar metal substrate,
  The resin coating layer is obtained by dispersing graphitized particles in a resin layer in which the triboelectric charge polarity with respect to iron powder is positive.
  The graphitized particles have a graphitization degree p (002) of 0.22 or more and 0.93 or less.And obtained by heat treatment of mesocarbon microbeads or mesophase pitch at 2300 to 3150 ° C. in an inert atmosphere,
  The resin coating layer can be achieved by a developer carrying member containing the graphitized particles in an amount of 25 wt% to 45 wt% with respect to the resin component in the resin coating layer.
[0023]
  (2) Also, the above purpose is to contain developeris doingDeveloper container,
  A developer carrier for carrying the developer contained in the developer container and transporting it to the development area, and a developer layer for regulating the layer thickness of the developer carried on the developer carrier A developing device having at least a thickness regulating member,
  The developer is a one-component negatively chargeable magnetic developer or a one-component negatively chargeable nonmagnetic developer,
  The developer carrying member is achieved by the developing device which is the developer carrying member of the above (1).
[0024]
  (3) Further, the above object is to form an image by visualizing the electrostatic latent image formed on the latent image carrier as a developer image with a developer and transferring the visualized developer image onto a transfer material. A process cartridge detachably attached to the image forming apparatus main body,
  A latent image carrier for carrying an electrostatic latent image;
  Charging means for charging the latent image carrier;
  The electrostatic latent image formed on the latent image bearing member is visualized as a developer image by developing with a developer, and after the developer image is transferred to a transfer material as a recording medium, Developing means for recovering the developer remaining on the latent image carrier;
Having at least
  The developing means contains a developer.is doingPresentImageAnd the presentImageA developer carrier for carrying the developer contained in the container and transporting the developer to the development area, the latent image carrier and the developing means are integrated;
  The developer carrier is a one-component negatively chargeable magnetic developer or a one-component negatively chargeable nonmagnetic developer, and
  The developer carrier isAbove (1)This is achieved by a process cartridge which is a developer carrier.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
As a result of intensive studies on the above problems, the inventors of the present invention can obtain the resin coating layer on the surface of the developer carrying member by containing a specific resin and baking a specific material as described above. By adopting a configuration in which graphitized particles are dispersed in a resin, a resin coating layer having excellent chargeability and mechanical strength for the toner and having a uniform surface shape is formed, and from the surface of the resin coating layer. The graphitized particles are less likely to be worn or detached, and even if the resin coating layer is worn, the graphitized particles are exposed again from within the resin coating layer, so that the surface coating layer of the developer carrier has a rough and uniform surface. The present inventors have found an effect that the surface shape and the material composition of the surface are difficult to change even when a large number of images are drawn. Furthermore, the present inventors have found that the resin coating layer containing the resin component and the graphitized particles has an effect of imparting uniform and high charge to the toner without causing toner contamination or toner charge-up.
[0026]
Next, the developer carrier of the present invention, the developing device using the developer carrier, and the process cartridge using the developer carrier will be described in more detail.
[0027]
First, the structure of the resin coating layer in the developer carrier of the present invention will be described. 1 to 4 are partial cross-sectional views of an embodiment of a developer carrying member of the present invention, and are schematic views showing a state in which a resin coating layer 1 is formed on a base 2 made of a metal cylindrical tube. In the figure, 3 is a magnet roller.
[0028]
In the developer carrying member of FIG. 1, graphitized particles 11 are dispersed in a binder resin 12 having a positively chargeable resin, forming irregularities on the surface of the resin coating layer 1, imparting conductivity, and releasing property to toner. In addition, it contributes to the charge imparting property to the toner.
[0029]
In the developer carrying member of FIG. 2, the graphitized particles 11 form irregularities on the surface of the resin coating layer 1, and in addition to the graphitized particles 11 in the binder resin 12 having a positively chargeable resin, a conductive agent. The conductivity is increased by adding 13 and the conductive agent 13 itself does not contribute much to the formation of substantial unevenness. However, not only the conductive agent 13 but also a form in which minute irregularities are formed by another added solid particle is included.
[0030]
In the developer carrying member of FIG. 3, the graphitized particles 11 form irregularities on the surface of the resin coating layer 1, and in addition to the graphitized particles 11 in the binder resin 12 having a positively chargeable resin, solid lubrication is performed. The lubricant 14 is improved by adding the agent 14, and the releasability with respect to the toner is further improved.
[0031]
In the developer carrying member of FIG. 4, in addition to the graphitized particles 11, in addition to the graphitized particles 11 in the binder resin 12 having a positively chargeable resin, in order to control the surface roughness by forming irregularities on the surface of the resin coating layer 1. A model diagram in which spherical particles 15 are added is shown, and the unevenness on the surface of the resin coating layer 1 can be more easily controlled by the particle size and added amount of the spherical particles 15. Such a configuration is effective when an elastic blade is used as the developer layer thickness regulating member, that is, when it is used for a developing device that is elastically pressed against the developer carrying member (via toner). It is. That is, when the particle diameter of the spherical particles 15 is larger than the particle diameter of the graphitized particles 11, the pressure contact force of the elastic regulating member is regulated by the spherical particles 15 on the surface of the resin coating layer 1, and the graphitized particles 11 are small. Forming irregularities also serves to adjust the contact charging opportunity between the toner and the binder resin 12 of the resin coating layer and the graphitized particles 11 and the releasability with the toner. In addition, when both the graphitized particles 11 and the spherical particles 15 contribute to the formation of irregularities on the surface of the resin coating layer 1, in addition to imparting irregularities to the surface of the spherical particles 15, conductivity, charge imparting properties, and wear resistance. By providing other functions such as properties, the triboelectric charging property to the toner is further improved. Although not shown, the resin coating layer 1 is made of a binder resin 12 having two or more, preferably all, positively chargeable resins of graphitized particles 11, conductive agent 13, solid lubricant 14 and spherical particles 15. It is particularly preferable that the composition is dispersed in the inside because each additive effect is exhibited synergistically.
[0032]
Next, the positively chargeable resin contained in the resin coating layer in the developer carrying member of the present invention will be described.
[0033]
Examples of the positively chargeable resin used in the present invention include nitrogen-containing polymers such as amino resins, silicone resins, polyamide resins, 4-vinylpyridine, 2-vinylpyridine, and polyvinylpyridine, methyl methacrylate, dimethylaminoethyl methacrylate, N- Methacrylate resins such as methyl-N-phenylaminoethyl methacrylate, diethylaminoethyl methacrylate amide, dimethylaminoethyl methacrylate amide, terpolymers of methacrylates such as polystyrene / n-butyl methacrylate / silane terpolymers, styrene-butadiene copolymers, Polycaprolactone and the like can be mentioned, among which amino resin is preferable. These resins have relatively high solubility in organic solvents, are excellent in dispersibility of other components such as graphitized particles, can be easily made thin, and have excellent adhesion to substrates and resistance. Not only is the wear resistance excellent, but in particular, when the developer is negatively charged, it can impart an appropriate charge to the developer, or with other resins, prepolymers, polymers, etc. By modifying by cross-linking reaction, the wear resistance can be further improved, and the solvent resistance and flexibility can be improved.
[0034]
An amino resin is a resin obtained by a condensation reaction between an amino group-containing compound and an aldehyde, and in the present invention, a melamine resin, a guanamine resin, an aniline resin, or a urea resin is preferably used. it can.
[0035]
Melamine resins generally form methylene bonds or methylene ether bonds formed between molecules by reacting melamine represented by the following formula (1) or a derivative thereof with methylol by reacting them under basic conditions and then dehydrating and condensing them. Obtained by crosslinking with, for example, methyl etherified melamine resin, (n- or i-) butyl etherified melamine resin, (n- or i-) butyl etherified trimethylol melamine resin, (n- or i-) butyl ether Hexamethylol melamine resin.
[0036]
[Chemical 1]

[0037]
[In the above formula (1), R₁, R₂, R_Three, R_Four, R_Five, R₆Is a hydrogen atom, an alkyl group such as a methyl group or an aliphatic or aromatic hydrocarbon residue such as a phenyl residue, a lower alkanol residue such as a methylol group or a butyrole group, or an alkoxy such as a methoxymethyl group or a butoxymethyl group These are alkyl residues, which may be the same or different. ]
[0038]
Guanamin resins are generally resins condensed by guanamine or its derivatives represented by the following formula (2) by addition polymerization reaction (dehydration, dealcoholization reaction) with formaldehyde, and modified with methanol or butanol as necessary. It doesn't matter. Examples include benzoguanamine resin, acetoguanamine resin, phthaloguanamine resin, and the like.
[0039]
[Chemical 2]

[0040]
[In the above formula (2), X₁Is an alkyl group such as a hydrogen atom or a methyl group or an aliphatic or aromatic hydrocarbon residue such as a phenyl residue, and X₂, X_Three, X_Four, X_FiveIs a hydrogen atom, a lower alkanol residue such as a methylol group or a butyrol group, or an alkoxyalkyl residue such as a methoxymethyl group or a butoxymethyl group, which may be the same or different. ]
[0041]
An aniline-based resin is a resin obtained by a condensation reaction between aniline and an aldehyde, and in the present invention, an aniline formaldehyde resin obtained by reacting aniline and formaldehyde in the presence of a hydrochloric acid catalyst to neutralize the acid is used. It can be preferably used.
[0042]
The urea resin is a resin obtained by heating urea and formaldehyde, generating methylolurea and dimethylolurea by an addition reaction, and performing a dehydration condensation reaction. In the present invention, dimethylol urea, dialkoxymethylurea cyclic trimer, alkoxymethylurea cyclic trimer, and the like can be used particularly preferably.
[0043]
The positively chargeable resin preferably has a weight average molecular weight (Mw) of 500 to 3,000. If the weight average molecular weight (Mw) is less than 500, the mechanical strength of the cured resin coating layer cannot be obtained, and satisfactory abrasion resistance may not be obtained. When the weight average molecular weight (Mw) exceeds 3,000, when the graphitized particles or other components are dispersed, the viscosity of the coating increases, and a suitable resin coating layer can be formed on the developing sleeve. It may disappear.
[0044]
The positively chargeable resins as mentioned above may be used by mixing with other resins as necessary in order to constitute the resin coating layer. As this resin, generally known resins can be used. In particular, when a resin containing a hydroxyl group (hydroxyl group) at the main chain or side chain terminal is used, the resin reacts with the positively chargeable resin and wear resistance. It is effective in improving the property (strength improvement), preventing photoconductor contamination, adhesion to the substrate, and preventing cracks in the surface layer film. For example, phenol resin, epoxy resin, polyamide resin, polyester resin, polycarbonate resin Polyolefin resin, silicone resin, fluorine resin, styrene resin, vinyl resin, cellulose resin, polyurethane resin, polyimide resin, acrylic resin, and the like. In view of mechanical strength, a curable resin is more preferable, but a thermoplastic resin is also applicable as long as it has sufficient mechanical strength. In the present invention, the resin coating layer formed on the developer carrier by the above-described forming material is a developer that is generated when the developer is fixed on the developer carrier by charge-up or the developer is charged up. In order to prevent poor charging from the surface of the carrier to the developer, it is desirable that it is conductive. The volume resistance value of the resin coating layer is preferably 10^FourΩ · cm or less, more preferably 10^ThreeΩ · cm or less. The volume resistance value of the resin coating layer on the surface of the developer carrying member is 10^FourIf it exceeds Ω · cm, poor charging of the developer is likely to occur, and as a result, a spot image and a wave pattern image accompanying the occurrence of so-called blotches are likely to occur on the developer carrying member.
[0045]
Next, graphitized particles contained in the resin coating layer in the developer carrying member of the present invention will be described.
[0046]
The developer carrier of the present invention is characterized in that the resin coating layer on the surface of the metal substrate contains graphitized particles obtained by firing mesocarbon microbead particles or bulk mesophase pitch particles. .
[0047]
The graphitized particles are 2500 after having been molded in a resin coating layer on the surface of the developer carrying member, such as coke and the like, solidified with tar pitch, etc., and fired at about 1000 ° C. to 1300 ° C. The raw material and manufacturing process of the graphitized particles are different from those of artificial graphite obtained by graphitization at about 3,000 ° C. to 3000 ° C. or crystalline graphite made of natural graphite. Therefore, although the graphitized particles have a slightly lower degree of graphitization than the previously used crystalline graphite, they have high conductivity and lubricity like the previously used crystalline graphite. Unlike the flakes or needles of crystalline graphite that have been used in the past, the shape is almost spherical, and the hardness of the particles themselves is relatively high. Accordingly, since the graphitized particles used in the present invention are easily dispersed uniformly in the resin coating layer, uniform surface roughness and abrasion resistance are given to the resin coating layer surface, and the shape of the particles themselves is not changed. Therefore, even if the resin coating layer is scraped or the particles themselves fall off due to the effect, the particles may protrude or be exposed again from the resin coating layer, and the change in the surface shape can be kept small. In addition, if the graphitized particles are used in the resin coating layer on the surface of the developer carrying member, the toner is not charged up, and the frictional charge is imparted to the toner more than when the conventional crystalline graphite is used. Performance can be improved.
[0048]
Usually, an organic compound having a boiling point of 500 ° C. or higher is carbonized via a solid phase or a liquid phase when heated in an inert gas phase under normal pressure, but begins to decompose at a temperature up to about 200 ° C., Cyclization occurs in the residue and then aromatizes up to 400 ° C. When this temperature is exceeded, polycondensation of aromatics proceeds. Among them, those that are liquid at this temperature, such as condensed polycyclic aromatics and pitches that are a mixture thereof, form a liquid crystal state composed of condensed polycyclic aromatic planar molecules at 400 ° C. or higher. This liquid crystal is called mesophase. In the mesophase, the polymer is further polymerized up to 500 ° C. and solidifies while forming a layered structure. The layered structure is highly selective and has a property of being easily graphitized by high-temperature treatment.
[0049]
As the graphitized particles used in the present invention, mesocarbon microbead particles or bulk mesophase pitch particles, which are particles in the above mesophase state, are used. Since these particles are optically anisotropic and composed of a single phase, graphitized particles obtained by graphitizing the particles can increase the degree of graphitization and maintain a spherical shape. it can. The optical anisotropy of mesocarbon microbead particles and bulk mesophase pitch particles arises from the lamination of aromatic molecules, and their ordering is further developed by graphitization, and graphitization with a high degree of graphitization. Particles are obtained.
[0050]
When using mesocarbon microbead particles as a raw material for obtaining graphitized particles used in the present invention, typical methods for obtaining the mesocarbon microbead particles include, for example, coal-based heavy oil or petroleum-based heavy oil. Heat treatment is performed at a temperature of 300 ° C. to 500 ° C., polycondensation produces crude mesocarbon microbead particles, and the reaction product is subjected to processing such as filtration, stationary sedimentation, and centrifugal separation. After separation, there is a method obtained by washing with a solvent such as benzene, toluene, xylene and drying.
[0051]
In addition, as a method of graphitizing using the mesocarbon microbead particles, first, the mesocarbon microbead particles that have been dried are first mechanically dispersed with a gentle force that does not cause destruction. It is preferable for preventing coalescence of subsequent particles and obtaining a uniform particle size. The mesocarbon microbead particles that have finished the primary dispersion are subjected to primary heat treatment at a temperature of 200 ° C. to 1500 ° C. in an inert atmosphere and carbonized. In order to prevent coalescence of the particles after graphitization and obtain a uniform particle size, it is preferable that the carbide after the primary heat treatment is mechanically dispersed with a mild force that does not destroy the carbide.
[0052]
The carbide after the secondary dispersion treatment is subjected to secondary heat treatment at about 2000 ° C. to 3500 ° C. in an inert atmosphere, whereby desired graphitized particles are obtained.
[0053]
Next, the case where bulk mesophase pitch particles are used as a raw material for obtaining graphitized particles used in the present invention will be described.
[0054]
A typical method for obtaining bulk mesophase pitch particles is, for example, a method of obtaining mesophase pitch particles by extracting β-resin from a coal tar pitch or the like by solvent fractionation, and performing hydrogenation and heavy processing. Further, there is a method in which mesophase pitch particles are obtained by finely pulverizing after the above-mentioned heavyening treatment and then removing solvent-soluble components with benzene or toluene. The bulk mesophase pitch particles used in the present invention preferably have a quinoline soluble content of 95% by mass or more. When the amount less than 95% by mass is used, the inside of the particles is difficult to be liquid phase carbonized, and solid phase carbonization causes the particles to remain in a crushed state, and a spherical shape may not be obtained.
[0055]
As a method of graphitizing using mesophase pitch particles, first, the bulk mesophase pitch particles are finely pulverized to 2 μm to 25 μm and heat-treated in air at about 200 ° C. to 350 ° C. Oxidize. By this oxidation treatment, the bulk mesophase pitch particles are infusible only on the surface, and melting and fusion during the graphitizing heat treatment in the next step are prevented. The oxidized mesophase pitch particles preferably have an oxygen content of 5% by mass to 15% by mass. If the amount is less than 5% by mass, the fusion of the particles during heat treatment may be promoted. If the amount exceeds 15% by mass, the inside of the particle is oxidized, and the shape is graphitized in a crushed state. It may be difficult to obtain.
[0056]
Next, desired graphitized particles are obtained by heat-treating the oxidized bulk mesophase pitch particles at about 2000 ° C. to 3500 ° C. in an inert atmosphere such as nitrogen or argon.
[0057]
In the method for producing graphitized particles using any of the above raw materials, the firing temperature of the graphitized particles is preferably 2000 ° C to 3500 ° C, and more preferably 2300 ° C to 3200 ° C. When the firing temperature is less than 2000 ° C., the graphitized particles are insufficiently graphitized, and the conductivity and lubricity may be reduced, resulting in toner charge-up, sleeve ghost, fog, image density. The image quality such as the image quality is likely to deteriorate, and when an elastic blade is used, a blade scratch may occur, and streaks, density unevenness, etc. are likely to occur in the image. When the firing temperature exceeds 3500 ° C., the graphitized particles may have a too high degree of graphitization. For this reason, the hardness of the graphitized particles decreases, and the wear resistance of the graphitized particles deteriorates. Wearability, mechanical strength of the resin coating layer, and chargeability to the toner may be reduced.
[0058]
Further, the graphitized particles used in the present invention preferably have a graphitization degree p (002) of 0.20 ≦ p (002) ≦ 0.95.
[0059]
The degree of graphitization p (002) is said to be Franklin's p value. By measuring the lattice spacing d (002) obtained from the X-ray diffraction diagram of graphite, d (002) = 3.440. -0.086 (1-p²). This p value indicates the proportion of the disordered portion of the carbon hexagonal mesh plane stack, and the smaller the p value, the greater the degree of graphitization.
[0060]
When p (002) exceeds 0.95, the wear resistance is excellent, but the conductivity and lubricity may be reduced and toner charge may occur, and sleeve ghost, fog, image density In the case of using an elastic blade, blade scratches are likely to occur, and streaks, density unevenness, etc. are likely to occur in the image. When p (002) is less than 0.20, the abrasion resistance of the graphitized particles is deteriorated, so that the wear resistance of the resin coating layer surface, the mechanical strength of the resin coating layer, and the charge imparting property to the toner are decreased. May end up.
[0061]
Moreover, in order to make the surface shape of the resin coating layer uniform, it is preferable that the graphitized particles obtained from any of the above raw materials have a uniform particle size distribution to some extent by classification, regardless of the production method.
[0062]
The graphitized particles used in the present invention preferably have a number average particle size of 0.5 μm to 25 μm, more preferably 1 μm to 20 μm.
[0063]
If the number average particle size of the graphitized particles is less than 0.5 μm, the effect of imparting uniform roughness to the surface and the effect of enhancing the charging performance are small, and the rapid and uniform charging to the developer becomes insufficient, and the resin Toner charge-up, toner contamination, and toner fusion due to wear of the coating layer are likely to occur, resulting in ghost deterioration and image density reduction. When the number average particle diameter exceeds 25 μm, the surface of the resin coating layer becomes too rough, and it becomes difficult to sufficiently charge the toner, and the mechanical strength of the resin coating layer decreases. Sometimes.
[0064]
In the present invention, for the purpose of adjusting the volume resistance value of the resin coating layer, a conductive agent may be dispersedly contained in the resin coating layer in combination with the graphitized particles. Examples of the conductive agent used in the present invention include conductive fine particles having a number average particle diameter of 1 μm or less, preferably 0.01 to 0.8 μm. When the number average particle diameter of the conductive fine particles exceeds 1 μm, it is difficult to control the volume resistance of the resin coating layer low, and toner contamination due to toner charge-up is likely to occur.
[0065]
In addition, as the conductive agent, fine metal powder such as aluminum, copper, nickel, silver, metal oxide such as antimony oxide, indium oxide, tin oxide, titanium oxide, zinc oxide, molybdenum oxide, potassium titanate, Various carbon fibers, furnace black, lamp black, thermal black, acetylene black, carbon black such as channel black, carbides such as graphite, metal fibers, and the like.
[0066]
In the present invention, among these, carbon black, in particular conductive amorphous carbon, is particularly excellent in electrical conductivity, and it is filled with a polymer material to impart conductivity, or just by controlling the amount of addition, Since arbitrary conductivity can be obtained to some extent, it is preferably used. Dispersion stability when used as a paint can also be good. Moreover, it is preferable to make the addition amount of these electroconductive substances suitable in this invention into the range of 1 mass part-100 mass parts with respect to 100 mass parts of binder resin. If it is less than 1 part by mass, it is usually difficult to lower the resistance value of the resin coating layer to a desired level, and toner adhesion to the binder resin used for the resin coating layer on the surface of the developer carrying member may occur. There is. When the amount exceeds 100 parts by mass, the strength (abrasion resistance) of the resin coating layer may be lowered particularly when a fine powder having a particle size of the order of submicron is used.
[0067]
The resin coating layer that can be used in the present invention can contain solid particles for forming irregularities on the surface of the resin coating layer. Examples of such solid particles include vinyl polymers and copolymers such as polymethyl methacrylate, polyethyl acrylate, polybutadiene, polyethylene, polypropylene, and polystyrene, phenol resins, polyamide resins, fluorine resins, silicone resins, and polyesters. Resin particles such as resin, oxide particles such as alumina, zinc oxide, silicone, titanium oxide and tin oxide, conductive particles such as carbonized particles, resin particles subjected to conductive treatment, and other organic materials such as imidazole compounds It is also possible to use the compound in the form of particles. In this case, the imidazole compound also serves to impart triboelectric charge to the toner.
[0068]
In particular, spherical particles are preferably used as the solid particles, and resin particles produced by a suspension polymerization method, a dispersion polymerization method, or the like are used as the spherical resin particles. Spherical resin particles can have a suitable surface roughness with a smaller addition amount, and a uniform surface shape can be easily obtained. Examples of such spherical resin particles include 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 and styrene resin particles. The resin particles obtained by the pulverization method may be used after thermally or physically spheroidizing.
[0069]
In addition, for example, an inorganic fine powder may be adhered or fixed to the surface of spherical resin particles. Examples of such inorganic fine powder include SiO.₂, SrTiO_Three, CeO₂, CrO, Al₂O_Three, ZnO, MgO, TiO₂Oxides such as Si_ThreeN_FourNitrides such as SiC, carbides such as SiC, CaSO_Four, BaSO_Four, CaCO_ThreeAnd sulfates and carbonates. Such inorganic fine powder may be used after being treated with a coupling agent. In particular, it can be preferably used for the purpose of improving the adhesion to the binder resin or for imparting hydrophobicity to the particles.
[0070]
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.
[0071]
By treating the spherical resin particle surface with inorganic fine powder in this way, dispersibility in the paint, uniformity of the coating surface, stain resistance of the resin coating layer, chargeability to the toner, resin coating The wear resistance of the layer can be improved.
[0072]
Conductive spherical particles may be used to impart spherical particles with stain resistance, wear resistance, and the like. As the conductive spherical particles, for example, as conductive spherical particles, the surface of a metal oxide such as titanium oxide, niobium oxide, manganese oxide, lead oxide, or a pigment such as barium sulfate is used. In some cases, an insulating metal oxide such as zinc oxide, copper oxide, iridium oxide or the like is doped with a metal having a different oxidation number to make it conductive.
[0073]
The volume resistivity of the conductive spherical particles is 10⁶It is preferable that it is below Ω · cm. 10⁶If it exceeds Ω · cm, it may cause problems such as toner charge-up.
[0074]
The true density of the added spherical particles is 3 g / cm^ThreeThe following are preferred. True density is 3g / cm^ThreeIf the average particle size exceeds 1, the dispersibility of the spherical particles may be insufficient in the resin coating layer, so that it becomes difficult to impart a uniform roughness to the surface of the resin coating layer. In addition, the strength of the particles may be insufficient, and the stain resistance and wear resistance, which are the advantages of these particles, may not be exhibited. Examples of the conductive spherical particles satisfying such conditions include spherical carbon particles, spherical resin particles surface-treated with a conductive substance, and spherical resin particles in which conductive fine particles are dispersed.
[0075]
Among these particles, it is particularly preferable to use conductive particles. Examples of such particles include conductive spherical particles previously proposed by the present inventors. That is, by imparting conductivity to the particles, it is difficult to accumulate charges on the particle surface due to the conductivity, and it is possible to reduce toner adhesion and improve the chargeability of the toner. In the present invention, the volume resistivity is 10 as the conductivity of the particles.⁶Ω · cm or less, more preferably 10^-3-10⁶The particles are preferably Ω · cm. The volume resistance of such particles is 10⁶If it exceeds Ω · cm, toner particles are likely to be contaminated and fused with spherical particles exposed on the surface of the resin coating layer due to wear, and rapid and uniform charging becomes difficult. Furthermore, the true density of the particles is 3 g / cm.^ThreeIt is more preferable that it is about or less. Even if conductive, if the true density of the particles is too high, the amount added must be increased to form the same roughness, and the difference in true density from the resin or resin composition will be large. The dispersion state of the particles at the time tends to be non-uniform, and therefore the dispersion state may be non-uniform even in the formed resin coating layer. Further, when the particles are spherical, the contact area with the developer layer thickness regulating member to be pressed is reduced, so the increase in sleeve rotation torque due to frictional force and the adhesion of toner can be reduced. preferable. In particular, when conductive spherical particles as shown below are used, a better effect can be obtained.
[0076]
The spherical particles preferably have a number average particle size of 0.3 μm to 30 μm. If it is less than 0.3 μm, it is difficult to form unevenness uniformly on the surface of the resin coating layer, and when trying to increase the surface roughness, the addition amount becomes excessive, the resin coating layer becomes brittle, and the wear resistance is extremely lowered. Sometimes. On the other hand, if it exceeds 30 μm, the particles protrude too much from the surface of the developer carrying member, so that the thickness of the developer layer becomes too large and the developer charge tends to decrease or become non-uniform. There may be a point of leakage to the electrostatic latent image carrier (photosensitive drum).
[0077]
Furthermore, in the resin coating layer of this invention, a charge control agent can be contained as needed. As the charge control agent, those similar to those used for toner particle formation described later can be used.
[0078]
The surface roughness of the resin coating layer on the surface of the developer carrying member preferably used in the present invention is generally 0.3 μm to 3 in terms of JIS centerline average roughness (Ra). Preferably it is in the range of 5 μm. However, the preferred surface roughness varies depending on the developing method. For example, in a developing apparatus using magnetic toner as shown in FIG. 5 and having a magnetic blade disposed with a gap between the developer carrier and the developer layer as a developer layer thickness regulating member, Ra is 0.3 μm to 2. It is preferably about 5 μm. When Ra is less than 0.3 μm, sufficient transportability of the developer cannot be obtained, and image density thin due to toner shortage, scattering or blotch due to excessive toner charging, etc. are likely to occur. On the other hand, when the thickness is larger than 2.5 μm, the frictional charge of the toner becomes non-uniform, and stripe unevenness, reversal fogging, and low image density due to insufficient charging are likely to occur. For example, in the case of a developing device in which an elastic member is used in pressure contact with a developer carrying member as shown in FIG. 6, Ra is preferably about 0.5 μm to 3.5 μm. When Ra is smaller than 0.5 μm, sufficient developer transportability may not be obtained, and image density thin due to toner shortage, scattering or blotch due to excessive toner charging may occur, Toner fusion to the developer carrier is also likely to occur. On the other hand, if it is larger than 3.5 μm, the frictional charge of the toner becomes non-uniform, and streak unevenness, reversal fogging, and low image density due to insufficient charging tend to occur.
[0079]
Furthermore, in the present invention, a solid lubricant can be mixed in the resin coating layer in order to further reduce the adhesion of the developer to the surface of the developer carrying member. Examples of the solid lubricant that can be used in this case include molybdenum disulfide, boron nitride, graphite, graphite fluoride, silver-selenium niobium, calcium chloride-graphite, talc and the like. The amount of these solid lubricants that can be used in the present invention is preferably in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the binder resin. When the amount is less than 1 part by mass, the effect of improving the adhesion of the developer to the surface of the binder resin of the resin coating layer is small. In this case, the strength (wearability) of the resin coating layer can be reduced. These solid lubricants preferably have a number average particle diameter of preferably about 0.2 to 20 μm, more preferably 1 to 15 μm. When the number average particle size of the solid lubricant is less than 0.2 μm, it is difficult to obtain sufficient lubricity, and when the number average particle size exceeds 20 μm, the shape of the resin coating layer surface is affected. The surface properties are likely to be uneven and the toner may be insufficiently charged in terms of uniform charging and the strength of the resin coating layer.
[0080]
Examples of the method for obtaining the resin coating layer of the developer-carrying member of the present invention include a method obtained by dispersing and mixing each component in a solvent to form a paint and coating on the substrate. For dispersion mixing of each component of the paint, a known dispersion apparatus using beads such as a sand mill, a paint shaker, a dyno mill, a pearl mill or the like can be suitably used. Moreover, as a coating method, well-known methods, such as a dipping method, a spray method, and a roll coat method, are applicable.
[0081]
Next, the developing device of the present invention will be described.
[0082]
The developing device of the present invention includes a developer container for containing a developer, a developer carrier for carrying the developer contained in the developer container and transporting the developer to a development region, and the developer carrier A developing device having at least a developer layer thickness regulating member for regulating the layer thickness of the developer carried on the substrate, wherein the developer carrying body of the present invention described above is used as the developer carrying body. And
[0083]
FIG. 5 is a schematic diagram of an embodiment of the developing device of the present invention.
[0084]
In FIG. 5, an electrostatic latent image carrier, for example, a photosensitive drum 51 that carries an electrostatic latent image formed by a known process, rotates in the direction of arrow B. The developing sleeve 58 as a developer carrying member carries a one-component developer having magnetic toner supplied to the developing container 53 and rotates in the direction of arrow A, thereby developing sleeve 58 as a developer carrying member. The developer is transported to the development area D where the photosensitive drum 51 faces. As shown in FIG. 5, in the developing roller 60, a magnet (magnet roller) 59 is disposed in the developing sleeve 58 in order to magnetically attract and hold the developer on the developing sleeve 58.
[0085]
The developing sleeve 58 used in the developing device of the present invention has a resin coating layer 57 coated on a metal cylindrical tube 56 as a base. Developer is fed into the developer container 53 from a developer supply container (not shown) via a developer supply member (such as a screw) 62. The developing container is divided into a first chamber 64 and a second chamber 65, and the developer fed into the first chamber 64 passes through a gap formed by the developing container 53 and the partition member 54 by the stirring and conveying member 55. To the second chamber 65. The developer is carried on the developing sleeve 58 by the action of magnetic force by the magnet roller 59. In the second chamber 65, a stirring member 61 for preventing the developer from staying is provided.
[0086]
The developer obtains a triboelectric charge that can develop the electrostatic latent image on the photosensitive drum 51 by friction between the magnetic toners and the resin coating layer 57 on the developing sleeve 58. In the example of FIG. 5, in order to regulate the layer thickness of the developer conveyed to the development area D, a magnetic regulation blade (doctor blade) 52 made of a ferromagnetic metal as a developer layer thickness regulating member is used as the developing sleeve 58. The developing container 53 is mounted so as to face the developing sleeve 58 with a gap of about 50 μm to 500 μm from the surface. A magnetic force line from the magnetic pole N <b> 1 of the magnet roller 59 concentrates on the magnetic regulation blade 52, whereby a thin layer of developer is formed on the developing sleeve 58. In the present invention, a nonmagnetic restriction blade can be used instead of the magnetic restriction blade 52.
[0087]
In this manner, the thickness of the thin developer layer formed on the developing sleeve 58 is preferably thinner than the minimum gap between the developing sleeve 58 and the photosensitive drum 51 in the developing region D.
[0088]
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 the developer as described above, that is, a non-contact developing device. The developer carrier of the present invention can also 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 58 and the photosensitive drum 51, ie, a so-called contact type developing device. In order to avoid complicated explanation, the following explanation will be made with the non-contact type developing device described above as an example.
[0089]
A developing bias voltage is applied to the developing sleeve 58 by a developing bias power source 63 as a biasing means in order to cause the one-component developer having magnetic toner carried on the developing sleeve 58 to fly. When a DC voltage is used as the developing bias voltage, the developing sleeve 58 has a voltage value between the potential of the image portion of the electrostatic latent image (the region visualized as the developer adheres) and the potential of the background portion. It is preferable to apply to.
[0090]
In order to increase the density of the developed image and improve the gradation, an alternating bias voltage may be applied to the developing sleeve 58 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 58 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.
[0091]
At this time, in the case of so-called regular development, toner is attached to the high potential portion of the electrostatic latent image having a high potential portion and a low potential portion, and in the case of so-called regular development, the toner is charged with a polarity opposite to that of the electrostatic latent image In the case of so-called reversal development, in which toner is attached to a low potential portion of an electrostatic latent image having a high potential portion and a low potential portion for visualization, the electrostatic latent image is charged to the same polarity as that of the electrostatic latent image. Use toner. In this case, the high potential and the low potential are expressed by absolute values. In any of these cases, the developer (toner) is charged by friction with at least the surface of the developing sleeve 58 (resin coating layer 57).
[0092]
FIG. 5 shows an example of a magnetic blade disposed away from the developing sleeve as the developer layer thickness regulating member for regulating the developer layer thickness on the developing sleeve 58, but as shown in FIG. An elastic restricting blade made of an elastic plate made of a rubber elastic material such as urethane rubber or silicone rubber, or a metal elastic material such as phosphor bronze or stainless steel is used. In the present invention, particularly in the system having this form, a remarkable effect can be obtained in terms of wear resistance and charge imparting ability as compared with the prior art. Can do. This is because in a developing device of the type in which the regulating blade is in contact with or pressed against, the toner layer forms a thin layer of the developer on the developing sleeve 58 while being subjected to stronger regulation. Since a thinner developer layer can be formed than in the case of the reference example 5, the load on the resin coating layer on the surface of the developing sleeve 58 is increased, and the resin coating layer is easily worn. In the present invention, wear of the resin coating layer can be reduced even in such a system, so that high durability can be achieved. Note that the contact pressure of the elastic regulating blade 67 with respect to the developing sleeve 58 is a linear pressure of 5 g / cm to 50 g / cm in that the toner regulation can be stabilized and the toner layer thickness can be made suitable. preferable. When the contact pressure of the elastic regulating blade 67 is less than the linear pressure of 5 g / cm, the regulation of the toner becomes weak, causing fogging and toner leakage. When the linear pressure exceeds 50 g / cm, Damage increases and tends to cause toner deterioration and fusion to the sleeve and blade.
[0093]
FIG. 5 and FIG. 6 are only schematic illustrations of the developing device of the present invention. In addition to the layer thickness regulating member described above, the shape of the developing container 53 (hopper), the presence / absence of the stirring blades 55 and 61, the magnetic pole Needless to say, there are various forms of the arrangement, the shape of the supply member 62, the presence or absence of a supply container, and the like.
[0094]
FIG. 7 shows an embodiment of the process cartridge of the present invention. The process cartridge of the present invention is a cartridge in which at least the developing means and the electrostatic latent image holding member are integrally formed, and can be attached to and detached from the image forming apparatus main body (for example, a copying machine, a laser beam printer, a facsimile machine). It is configured.
[0095]
In the embodiment shown in FIG. 7, the developing means 71, the drum-shaped electrostatic latent image carrier (photosensitive drum) 51, the cleaning means 72 having the cleaning blade 72a, and the contact (roller) charging means 73 as the primary charging means are provided. An integrated process cartridge 70 is illustrated. In the present embodiment, the developing means 71 includes a developing sleeve 58, an elastic regulating blade 67, and a one-component developer (toner) T having magnetic toner in the developing container 53. Sometimes a predetermined electric field is formed between the photosensitive drum 51 and the developing sleeve 58 by the developing bias voltage from the bias applying means, and the developing process is performed. The distance between the photosensitive drum 51 and the developing sleeve 58 is very important for suitably carrying out this developing process.
[0096]
In the above description, the embodiment in which the four constituent elements of the developing unit 71, the electrostatic latent image carrier 51, the cleaning unit 72, and the primary charging unit 73 are integrally formed into a cartridge has been described. It is sufficient that at least two components with the electrostatic latent image carrier are integrally formed into a cartridge. The three components of the developing means, the electrostatic latent image carrier and the cleaning means, the developing means, It is possible to integrally form a cartridge by adding three components of the electrostatic latent image carrier and the primary charging means, or other components.
[0097]
Next, the developer used in the developing device of the present invention will be described.
[0098]
The developer that can be used in the present invention is a toner in which at least a binder resin, a colorant, and, if necessary, various additives are further added to the toner particles. Incidentally, in the one-component developer, the toner substantially means the developer. The toner preferably has a weight average particle diameter of 4 μm to 11 μm. If such a toner is used, the toner charge amount or image quality and image density are balanced.
[0099]
As the binder resin for the toner, generally known resins can be used, and examples thereof include vinyl resins, polyester resins, polyurethane resins, epoxy resins, phenol resins, etc. Among them, vinyl resins and polyester resins are particularly preferable. preferable.
[0100]
As the carboxylic acid-containing monomer that can be used in the vinyl resin, a half-ester monomer of dicarboxylic acid is particularly preferable. For example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate, monoester maleate Half esters of α, β-unsaturated dicarboxylic acids such as phenyl, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate, etc .; monobutyl n-butenyl succinate, monomethyl n-octenyl succinate, n-butenylmalon Half-esters of alkenyldicarboxylic acids such as monoethyl acid, monomethyl n-dodecenyl glutamate, monobutyl n-butenyladipate; monomethyl phthalate, monoethyl phthalate, And half esters of aromatic dicarboxylic acids such as monobutyl ester of tartrate.
[0101]
Further, examples of the comonomer other than the carboxylic acid-containing monomer for obtaining the vinyl resin that can be used in the present invention include the following.
[0102]
For example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4- Dimethyl styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl Styrene such as styrene and its derivatives; Ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; Unsaturated polyenes such as butadiene; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride Vinyl acetate, vinyl propionate, vinyl benzoate, etc. Esters: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, Α-methylene aliphatic monocarboxylic acid esters such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate Acrylic acid esters such as dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, and phenyl acrylate; vinyl methyl ether, vinyl ester Vinyl ethers such as chill ether and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone and other N- Vinyl monomers; vinyl naphthalenes; acrylic monomers or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; are used alone or in combination of two or more.
[0103]
Among these, a combination of monomers that becomes a styrene copolymer or a styrene-acrylic copolymer is preferable.
[0104]
As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used.
[0105]
The vinyl polymer that can be used in the present invention may be a polymer crosslinked with a crosslinkable monomer as exemplified below.
[0106]
Aromatic divinyl compounds, such as divinylbenzene, divinylnaphthalene, etc .; diacrylate compounds linked by alkyl chains, such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylate of the above compound with a methacrylate; a diacrylate compound linked by an alkyl chain containing an ether bond For example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol 600 diacrylate, dipropylene glycol diacrylate, and those in which the acrylate of the above compound is replaced by methacrylate; diacrylate compounds linked by a chain containing an aromatic group and an ether bond, such as polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and acrylates of the above compounds were replaced with methacrylate. Further, polyester type diacrylate compounds, for example, trade name MANDA (Nippon Kayaku) can be mentioned. Examples of the polyfunctional cross-linking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds replaced with methacrylate; For example, lucyanurate and triallyl trimellitate;
[0107]
These crosslinking agents are preferably used in an amount of 0.01 to 5 parts by mass (preferably 0.03 to 3 parts by mass) with respect to 100 parts by mass of the other monomer components.
[0108]
Among these, aromatic divinyl compounds (particularly divinylbenzene) and diacrylate compounds linked by a chain containing an aromatic group and an ether bond can be preferably used.
[0109]
Further, when the developer is negatively charged, it is a good example to use a polyester resin. As the polyester resin, a polyester resin comprising a polybasic acid component and a polyhydric alcohol component condensation polymer is used. preferable.
[0110]
The composition of the polyester resin that can be used in the present invention is as follows.
[0111]
Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, and bisphenol and its derivatives represented by the following formula (A);
[0112]
[Chemical 3]

[0113]
(In the above formula, R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.)
[0114]
In addition, diols represented by the following formula (B);
[0115]
[Formula 4]

Diols such as
[0116]
Divalent acid components include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or their anhydrides, lower alkyl esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid. Or its anhydride, lower alkyl ester; alkenyl succinic acid or alkyl succinic acid such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or anhydride, lower alkyl ester of the acid; fumaric acid, maleic acid, citraconic acid, itacone Examples thereof include unsaturated dicarboxylic acids such as acids or anhydrides thereof, dicarboxylic acids such as lower alkyl esters, and derivatives thereof.
[0117]
In addition, a trivalent or higher alcohol component that also functions as a crosslinking component and a trivalent or higher acid component can be used in combination.
[0118]
Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, etc. And trihydric or higher polyhydric alcohols.
[0119]
Trivalent or higher polyvalent carboxylic acid components include trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid. 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra ( Methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, and anhydrides thereof, lower alkyl esters, tetracarboxylic acid represented by the following formula (C), and the like Examples thereof include polyvalent carboxylic acids such as anhydrides and lower alkyl esters and derivatives thereof.
[0120]
[Chemical formula 5]

[0121]
(In the above formula, X represents an alkylene group or alkenylene group having 5 to 30 carbon atoms having one or more side chains having 3 or more carbon atoms.)
[0122]
The alcohol component used in the present invention is 40 mol% to 60 mol%, preferably 45 mol% to 55 mol%, and the acid component is 60 mol% to 40 mol%, preferably 55 mol% to 45 mol%. It is preferable.
[0123]
The trivalent or higher polyvalent component is preferably 5 mol% to 60 mol% in all components.
[0124]
The alcohol component of the polyester resin preferred in the present invention is a bisphenol derivative represented by the above formula (A), and the acid component is phthalic acid, terephthalic acid, isophthalic acid or its anhydride; succinic acid, n-dodecenyl succinic acid Or the anhydride, dicarboxylic acids, such as fumaric acid, maleic acid, and maleic anhydride, trimellitic acid, or tricarboxylic acid of its anhydride is mentioned.
[0125]
Negatively chargeable developers having polyester resins obtained with these acids and alcohols are excellent in charging characteristics and are preferably used in the present invention.
[0126]
The binder resin thus obtained has a glass transition temperature (Tg) of 45 ° C. to 75 ° C., preferably 50 ° C. to 70 ° C., and number average molecular weight (Mn) 1,500 to 30,000, preferably 2, It is suitable for the developer used in the developing device of the present invention that the molecular weight is 000 to 15,000 and the weight average molecular weight (Mw) is 6,000 to 800,000, preferably 10,000 to 500,000.
[0127]
In the developer used in the developing device of the present invention, for the purpose of improving charging characteristics, a charge control agent can be blended (internally added) into toner particles or mixed (externally added) with toner particles. This is because the charge control agent enables optimal charge amount control according to the development system.
[0128]
For example, as a positive charge control agent, modified products such as nigrosine, triaminotriphenylmethane dyes and fatty acid metal salts; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, etc. Quaternary ammonium salts of: diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate, or a combination of two or more Can do. Among these, charge control agents such as nigrosine compounds, triaminotriphenylmethane dyes, and organic quaternary ammonium salts are particularly preferably used.
[0129]
As the negative charge control agent, for example, organometallic compounds and chelate compounds are effective. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, chromium 3,5-di-tert-butylsalicylate, and in particular, acetylacetone metal complex, monoazo metal complex, naphthoic acid or salicylic acid metal complex or A salt is preferable, and a salicylic acid metal complex, a monoazo metal complex, or a salicylic acid metal salt is particularly preferable.
[0130]
The above charge control agent is preferably used in the form of fine particles. In this case, the number average particle diameter of the charge control agent is specifically 4 μm or less, more preferably 3 μm or less.
[0131]
When the charge control agent is internally added to the toner particles, it is preferably used in an amount of 0.1 to 20 parts by weight, more preferably 0.2 parts by weight with respect to 100 parts by weight of the binder resin constituting the toner particles. Parts to 10 parts by mass.
[0132]
Further, when the developer that can be used in the present invention is a magnetic developer, the magnetic material blended in the toner particles includes iron oxides such as magnetite, maghemite, and ferrite, and iron oxides including other metal oxides. Metals such as Fe, Co, Ni, or these metals and Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W , Alloys with metals such as V, and mixtures thereof.
[0133]
Conventionally, as a magnetic material, triiron tetroxide (Fe_ThreeO_Four), Iron sesquioxide (γ-Fe₂O_Three), Zinc iron oxide (ZnFe₂O_Four), Iron yttrium oxide (Y_ThreeFe_FiveO₁₂), Cadmium oxide (CdFe₂O_Four), Gadolinium oxide (Gd)_ThreeFe_Five-O₁₂), Copper iron oxide (CuFe₂O_Four), Lead iron oxide (PbFe₁₂-O₁₉), Nickel iron oxide (NiFe)₂O_Four), Neodymium iron oxide (NdFe₂O_Three), Iron barium oxide (BaFe)₁₂O₁₉), Magnesium iron oxide (MgFe₂O_Four), Iron manganese oxide (MnFe₂O_Four), Iron lanthanum oxide (LaFeO)_Three), Iron powder (Fe), cobalt powder (Co), nickel powder (Ni), and the like are known. As the developer that can be used in the developing device of the present invention, the above-described magnetic materials may be used alone or 2 Select and use combinations of more than one species. Among the materials listed above, a particularly suitable magnetic material is a fine powder of iron trioxide or γ-iron trioxide. These ferromagnets have an average particle size of about 0.1 μm to 2 μm, and have a magnetic property when applied with 7958 kA / m (10 kOersted)._c) 1.6 kA / m to 16 kA / m, saturation magnetization (σ_s50 Am²/ Kg-200Am²/ Kg, remanent magnetization (σ_r) 2 Am²/ Kg-20Am²/ Kg is preferred.
[0134]
It is good to use 10 mass parts-200 mass parts of a magnetic body with respect to 100 mass parts of binder resin, Preferably it is 20 mass parts-150 mass parts.
[0135]
In addition, you may use the said magnetic body combining the role as a coloring agent.
[0136]
In the developer that can be used in the present invention, the colorant that can be contained in the toner particles includes any appropriate pigment or dye.
[0137]
Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, Bengala, phthalocyanine blue, and indanthrene blue. These pigments are preferably used in an amount of 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, with respect to 100 parts by mass of the binder resin. For the same purpose, further dyes are used. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, methine dyes, and 0.1 parts by mass to 20 parts by mass, preferably 0.3 parts by mass to 10 parts by mass with respect to 100 parts by mass of the binder resin. It is preferable to use it.
[0138]
Further, the developer used in the present invention may contain one or more release agents in the toner particles as necessary.
[0139]
Examples of the release agent include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax, and oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax. Block copolymer; waxes mainly composed of fatty acid esters such as carnauba wax, Fischer-Tropsch wax, sazol wax, and montanic acid ester wax, and part or all of fatty acid esters such as deoxidized carnauba wax And the like. In addition, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid, unsaturated fatty acids such as brandic acid, eleostearic acid, and valinalic acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, ceryl Saturated alcohols such as alcohol and merisyl alcohol, polyhydric alcohols such as sorbitol, fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide, methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis Saturated fatty acid bisamides such as lauric acid amide and hexamethylene bis stearic acid amide, ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl adipic acid amide, N, N -Unsaturated fatty acid amides such as dioleyl sebacic acid amide, m-xylene bis stearic acid amide, aromatic bisamides such as N, N'-distearylisophthalic acid amide, calcium stearate, calcium laurate, zinc stearate , Fatty acid metal salts such as magnesium stearate (generally referred to as metal soap), waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid, Examples include partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols, and methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable oils and the like.
[0140]
The release agent is used in an amount of 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.
[0141]
These release agents are usually contained in the binder resin by a method in which the resin is dissolved in a solvent, the temperature of the resin solution is increased, and the mixture is added and mixed while stirring, or by mixing during kneading.
[0142]
Developers that can be used in the present invention include inorganic fine powders such as silica fine powder, titanium oxide, and alumina in order to improve environmental stability, charging stability, developability, fluidity, storage stability and cleaning properties. In other words, it is preferably present in the vicinity of the toner particle surface. Among these, silica fine powder is preferable.
[0143]
For example, the silica fine powder can use both a so-called dry method produced by vapor phase oxidation of a silicon halide or dry silica called fumed silica, and so-called wet silica produced from water glass or the like. However, there are few silanol groups on the surface and inside the silica fine powder, and Na₂O, SO_Three ^2-For example, dry silica with less production residue is preferred. In dry silica, it is also possible to obtain composite fine powders of silica and other metal oxides by using other metal halogen compounds such as aluminum chloride and titanium chloride together with silicon halogen compounds in the production process. They are also included.
[0144]
As the inorganic fine powder that can be used in the present invention, an organically treated inorganic fine powder can also be used. As such an organic treatment method, there is a method of treating with an organic metal compound such as a silane coupling agent or a titanium coupling agent that reacts or physically adsorbs with the inorganic fine powder. By performing such treatment, the hydrophobicity of the inorganic fine powder can be promoted, and a toner excellent in environmental stability especially under high humidity can be obtained, so that it can be preferably used. Examples of silane coupling agents used for organic treatment include 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-divinyl Tetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethyl containing 2 to 12 siloxane units per molecule, each containing a hydroxyl group bonded to one silicon atom at the terminal unit Polysiloxane etc. are mentioned.
[0145]
In addition, aminopropyltrimethoxysilane having nitrogen atom, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyl Trimethoxysilane, dioctylaminopropyldimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ-propylbenzylamine, etc. These silane coupling agents are also used alone or in combination. Preferred silane coupling agents include hexamethyldisilazane (HMDS) and aminopropyltrimethoxysilane.
[0146]
Examples of the method for treating the inorganic fine powder with the silane coupling agent include a spray method, an organic solvent method, and an aqueous solution method, but are not particularly limited.
[0147]
As other organic treatment, it is also possible to use fine powder treated with silicone oil. As a preferable silicone oil, the viscosity at 250 ° C. is 0.5 mm.²/ S-10000mm²/ S, preferably 1 mm²/ S ~ 1000mm²For example, methyl hydrogen silicone oil, dimethyl silicone oil, phenylmethyl silicone oil, chloromethyl silicone oil, alkyl modified silicone oil, fatty acid modified silicone oil, polyoxyalkylene modified silicone oil, fluorine modified silicone An oil etc. are mentioned.
[0148]
The inorganic fine powder used in the present invention has a specific surface area of 30 m by nitrogen adsorption measured by the BET method.²/ G or more, especially 50m²/ G-400m²The inorganic fine powder used in the present invention is used in an amount of 0.01 to 8 parts by weight, preferably 0 to 100 parts by weight of toner particles. .1 part by mass to 5 parts by mass, particularly preferably 0.2 part by mass to 3 parts by mass. When the amount is less than 0.01 part by weight, the effect of improving the aggregation of the developer is poor. When the amount exceeds 8 parts by weight, the inorganic fine powder does not adhere to the toner particle surface and exists in a free state. Is likely to occur, it becomes difficult to maintain a uniform and appropriate charge amount of the developer, and may cause adverse effects such as deterioration in development characteristics.
[0149]
To the developer that can be used in the present invention, an external additive other than the inorganic fine powder may be further added. For example, lubricants such as Teflon (registered trademark), zinc stearate, and polyvinylidene fluoride, among which polyvinylidene fluoride is preferable. Alternatively, abrasives such as cerium oxide, strontium titanate, and strontium silicate, among which strontium titanate is preferable. Other anti-caking agents, or conductivity imparting agents such as carbon black, zinc oxide, antimony oxide and tin oxide, or white and black fine particles having opposite polarity can also be used in small amounts as developability improvers.
[0150]
These external additives may be used in an amount of 0.01 to 10 parts by mass (preferably 0.1 to 7 parts by mass) with respect to 100 parts by mass of toner particles.
[0151]
To create a developer, a binder resin, a pigment or dye as a colorant, a magnetic material, a release agent, if necessary, a charge control agent, and other additives are mixed with a mixer such as a Henschel mixer or a ball mixer. After thoroughly mixing, the release agent, pigment, dye, and magnetic substance are dispersed or dissolved in the resin mixed with each other by melting using a heat kneader such as a heating roll, kneader or extruder. After cooling and solidification, toner particles can be obtained by pulverization and classification. Furthermore, if necessary, desired additives can be sufficiently mixed by a mixer such as a Henschel mixer to obtain a toner (developer).
[0152]
Such a toner is preferably used after being subjected to a spheroidizing treatment and a surface smoothing treatment by various methods. As such a method, in a device having a stirring blade or a blade, and a liner or a casing, for example, when the toner is passed through a minute gap between the blade and the liner, the surface is smoothed by a mechanical force. Or a method of spheroidizing the toner, a method of suspending the toner in warm water to spheroidize, a method of exposing the toner to a hot air stream and spheroidizing. In addition, as a method for directly producing a spherical toner, there is a method in which a mixture containing a monomer as a toner binder resin as a main component is suspended in water and polymerized to form a toner. As a general method, a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, a release agent, and other additives are uniformly dissolved or dispersed in a single amount. After forming the body composition, the monomer composition is dispersed in a continuous layer containing a dispersion stabilizer, for example, an aqueous phase with an appropriate stirrer, and further subjected to a polymerization reaction to obtain a desired composition. This is a method for obtaining a developer having a particle size of.
[0153]
The physical property measurement method according to the present invention will be described below.
[0154]
(1) Measurement of the charging polarity of the binder resin used to form the resin coating layer
Sample plate production method: Bar coater (# 60) on a SUS plate with a solution in which a resin used for forming a resin coating layer (excluding a conductive substance) for measuring the charge polarity is dissolved or dispersed in an organic solvent (The drying and heating temperature and time are until the solution is completely evaporated in the case of a thermoplastic resin, and the resin is completely crosslinked in the case of a thermosetting resin.) To make a sample plate. With this sample plate grounded, it is left to stand overnight at 23 ° C. and 60% RH.
[0155]
Particle adjustment method: With iron powder (particle size of about 100 μm) in contact with the ground, leave it overnight at 23 ° C. and 60% RH.
[0156]
Measurement method: Measurement is performed in an environment of 23 ° C. and 60% RH. First, the sample plate produced above is set in a surface charge measuring device TS-100AS (manufactured by Toshiba Chemical Co., Ltd.) shown in FIG. 8, and the electrometer 85 is grounded to make the value zero. The iron powder 81 conditioned as described above is put in the dropping device 82, the START switch is pressed, the iron powder 81 is dropped on the sample plate 83 for 20 seconds, and is received by the receiver 84 which has been grounded in advance. At this time, the polarity indicated by the electrometer 85 was read and used as the charging polarity of the binder resin with respect to the iron powder. Reference numeral 86 denotes a condenser.
[0157]
(2) Weight average molecular weight of binder resin used for forming resin coating layer
The measurement was performed by GPC using THF as a developing solvent under the following conditions.
Measuring device: HLC8120GPC
Measurement conditions: measurement temperature 40 ° C., flow rate 0.6 ml / min, sample injection amount 20 μl, sample concentration 0.5%
Detector: Refractometer
Column condition: TSKgel Super2000
TSKgel Super3000
TSKgel Super4000
TSKgel Super5000
TSKgel Super6000
TSK Guard Column H-H was ligated.
[0158]
(3) Graphitization degree of graphitized particles p (002)
The degree of graphitization p (002) is determined by measuring the lattice spacing d (002) obtained from the X-ray diffraction spectrum of graphite using a powerful fully automatic X-ray diffractometer “MXP18” system manufactured by Mac Science. (002) = 3.440-0.086 (1-p²).
[0159]
The lattice interval d (002) is CuKα as an X-ray source, and the CuKβ line is removed by a nickel filter. High-purity silicon was used as a standard substance, and calculation was performed from the peak positions of the C (002) and Si (111) diffraction patterns. The main measurement conditions are as follows.
X-ray generator: 18kW
Goniometer: Horizontal goniometer
Monochromator: Use
Tube voltage: 30.0kV
Tube current: 10.0mA
Measurement method: Continuous method
Scan axis: 2θ / θ
Sampling interval: 0.020 deg
Scan speed: 6.000 deg / min
Divergence slit: 0.50deg
Scattering slit: 0.50deg
Receiving slit: 0.30mm
[0160]
(4) Measurement of toner and resin particle size
As a measuring device, Coulter counter TA-II type, Coulter multisizer II or Coulter multisizer III (both manufactured by Beckman Coulter, Inc.) are used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. For example, ISOTON-II (manufactured by Beckman Coulter) can be used. As a measuring method, 0.1 ml to 5 ml of a surfactant, preferably alkylbenzenesulfonate is added as a dispersant to 100 ml to 150 ml of the electrolytic aqueous solution, and 2 mg to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of measurement samples are measured using the 100 μm aperture or the 30 μm aperture as the aperture by the measuring device. The volume distribution and the number distribution were calculated. From this result, the weight-based weight average particle diameter (D4) obtained from the volume distribution and the number-based length average particle diameter (D1) obtained from the number distribution (both the median value of each channel is the representative value for each channel). Asked).
[0161]
(5) Measurement of particle size of conductive particles of 1 μm or more
The particle size of conductive particles such as graphitized particles was measured using a Coulter LS-130 or LS-230 particle size distribution meter (manufactured by Beckman Coulter, Inc.), a laser diffraction particle size distribution meter. As a measuring method, an aqueous module is used, and pure water is used as a measuring solvent. The measurement system of the particle size distribution meter was washed with pure water for about 5 minutes, and 10 mg to 25 mg of sodium sulfite was added to the measurement system as an antifoaming agent to execute the background function.
[0162]
Next, 3 to 4 drops of a surfactant was added to 10 ml of pure water, and 5 to 25 mg of a measurement sample was further added. The aqueous solution in which the sample is suspended is subjected to a dispersion treatment for 1 to 3 minutes with an ultrasonic disperser to obtain a sample solution. The sample solution is gradually added into the measurement system of the measurement device, and the PIDS on the screen of the device is 45. Measurement was carried out by adjusting the sample concentration in the measurement system so that it was in the range of% to 55%, and the number average particle diameter calculated from the number distribution was determined.
[0163]
(6) Measurement of particle size of conductive fine particles of less than 1 μm
The particle diameter of the conductive fine particles was measured using an electron microscope. The shooting magnification was set to 60,000 times, but when it was difficult, the photograph was enlarged and printed so as to be 60,000 times after shooting at a low magnification. Measure the primary particle size on the photo. At this time, the major axis and the minor axis are measured, and the average value is defined as the particle size. This was measured for 100 samples, and the 50% value was taken as the average particle size.
[0164]
(7) Measurement of centerline average roughness (Ra) of developer carrier surface
Based on the surface roughness of JIS B0601 (2001), the surface roughness meter SE-3400 manufactured by Kosaka Laboratories respectively measured 3 points in the axial direction × 3 points in the circumferential direction = 9 points, and took the average value. The measurement conditions were a cutoff of 0.8 mm, a measurement distance of 8.0 mm, and a feed rate of 0.1 mm / sec.
[0165]
(8) Measurement of volume resistance of resin coating layer
A resin coating layer having a thickness of 7 μm to 20 μm is formed on a PET sheet having a thickness of 100 μm, and is compliant with ASTM standard (D-991-82) and Japan Rubber Association standard SRIS (2301-1969). The measurement was performed using a voltage drop type digital ohmmeter (manufactured by Kawaguchi Electric Mfg. Co., Ltd.) provided with an electrode having a four-terminal structure for measuring volume resistance of rubber and plastic. The measurement environment was 20 ° C. to 25 ° C. and 50% RH to 60% RH.
[0166]
(9) Measurement of particle volume resistance
The granular sample was put in an aluminum ring of 40 mmφ, pressure-molded at 2500 N, and the volume resistance value was measured with a resistivity meter Loresta AP or Hiresta IP (both manufactured by Mitsubishi Yuka) using a 4-terminal probe. The measurement environment was 20 ° C. to 25 ° C. and 50% RH to 60% RH.
[0167]
(10) Measurement of true density of spherical particles
The true density of the spherical particles used in the present invention was measured using a dry density meter Accupic 1330 (manufactured by Shimadzu Corporation).
[0168]
(11) Measurement of resin coating layer thickness (scrap amount)
A laser dimension measuring device manufactured by KEYENCE Corp. was used to measure the amount of coating layer scraping (film scraping). Using the controller LS-5500 and the sensor head LS-540T, the sensor part was separately fixed to an apparatus equipped with a sleeve fixing jig and a sleeve feeding mechanism, and measurement was performed from the average value of the outer diameter of the sleeve. The measurement was divided into 30 with respect to the longitudinal direction of the sleeve and measured at 30 points. Further, after rotating the sleeve by 90 ° in the circumferential direction, measurements were further made at 30 points, a total of 60 points, and the average value was taken. The outer diameter of the sleeve before forming the surface coating layer was measured in advance, and the outer diameter after forming the surface coating layer and the outer diameter after durable use were measured, and the difference between them was taken as the coating film thickness and the amount of abrasion.
[0169]
Embodiments of the present invention are shown below.
[0170]
[Embodiment 1]
A developer carrier used in a developing device for developing and visualizing a latent image formed on a latent image carrier with a developer conveyed and carried on the surface of the developer carrier,
It has a resin coating layer on the surface of a cylindrical or columnar metal substrate, and the resin coating layer contains at least graphitized particles obtained by firing positively charged resin and mesocarbon microbead particles or bulk mesophase pitch particles. A developer carrier characterized by containing.
[0171]
[Embodiment 2]
A developer container for containing the developer, a developer carrier for carrying the developer contained in the developer container and transporting it to the development area, and a developer carried on the developer carrier A developing device having at least a developer layer thickness regulating member for regulating a layer thickness, wherein the developer carrying member is the developer carrying member of the first embodiment.
[0172]
[Embodiment 3]
The electrostatic latent image formed on the latent image carrier is visualized as a developer image with a developer, and the visualized developer image is transferred to a transfer material to form an image on the image forming apparatus main body. A process cartridge that is detachably attached to the cartridge,
Using a developer, a latent image carrier for carrying an electrostatic latent image, a charging means for charging the latent image carrier, and an electrostatic latent image formed on the latent image carrier At least developing means for visualizing a developer image by performing development, and for recovering the developer remaining on the latent image carrier after the developer image is transferred to a transfer material as a recording medium; And the developing means carries a developer container for containing the developer, and a developer carrier for carrying the developer contained in the developer container and transporting the developer to the development area. A process cartridge, wherein the latent image carrier and the developing means are integrated, and the developer carrier is the developer carrier of the first embodiment.
[0173]
[Embodiment 4]
In any one of Embodiments 1 to 3, the positively chargeable resin is an amino resin.
[0174]
[Embodiment 5]
In Embodiment 4, the amino resin is a melamine resin, a guanamine resin, an aniline resin or a urea resin.
[0175]
[Embodiment 6]
In any one of Embodiments 1-5, the graphitization degree p (002) of a graphitized particle is 0.20 <= p (002) <= 0.95.
[0176]
[Embodiment 7]
In any one of Embodiments 1-6, the number average particle diameter of a graphitized particle is 0.5 micrometer-25 micrometers.
[0177]
【Example】
Next, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto. Note that “parts” and “%” in the following formulations are all “parts by mass” and “% by mass” unless otherwise specified.
[0178]
[Production Example 1 of Developer Carrier]
As the resin for forming the resin coating layer, the methyl etherified melamine resin (A-1) and the bisphenol type polyester resin (A-8) listed in Table 1 were selected. First, A-1: 30 parts, A-8: 70 parts, and 220 parts of methanol (including methanol in the resin solution) were subjected to sand mill dispersion for 1 hour with φ2 mm glass particles, and then the glass particles were separated by sieving. This resin solution was applied onto a SUS plate with a bar coater (# 60), and this was heated and cured at 150 ° C./30 minutes to prepare a sample plate. The sample plate was allowed to stand overnight at 23 ° C. and 60% RH in a grounded state. When the triboelectric charge polarity with the iron powder was measured by the method described above, it showed positive chargeability. In addition, the result of measuring the charging polarity of each resin (single) listed in Table 1 by the same method as described above is also described.
[0179]
Next, as graphitized particles, mesocarbon microbead particles were thermally stabilized in an oxidizing atmosphere and then graphitized by firing at 2800 ° C. Graphitized particles B-1 having a number average diameter of 5.5 μm were obtained. Was used. The physical properties of graphitized particle B-1 are shown in Table 2. Further, Table 3 shows the physical properties of the particles for imparting irregularities to the resin coating layer.
[0180]
Resin A-1 (Methanol 50% solution) 60 parts
Resin A-8 (Methanol 50% solution) 140 parts
Graphite particles B-1 36 parts
Conductive carbon black 4 parts
Concave-forming particles C-1 12 parts
120 parts of methanol
Glass beads having a diameter of 1 mm were added as media particles to the above material, dispersed for 2 hours with a sand mill, the beads were separated using a sieve, and the solid content was adjusted to 35% with methanol to obtain a coating solution. Using this coating solution, an aluminum cylindrical tube with an outer diameter of 20 mmφ and a center line average roughness Ra = 0.2 μm is vertically set up, rotated at a constant speed, and masked at the upper and lower ends, and sprayed. The resin coating layer was formed by applying the gun while descending at a constant speed. Subsequently, the resin coating layer was cured by heating at 150 ° C. for 30 minutes in a hot air drying furnace to prepare a developer carrying member (developing sleeve) S-1. Table 4 lists the formulation and physical properties of the resin coating layer of the developer carrier S-1.
[0181]
[Production Examples 2 to 10 and Comparative Production Examples 1 to 7]
According to the formulation shown in Table 4, after preparing a coating liquid having a solid content adjusted to 35% with methanol in the same manner as in Production Example 1 of the developer carrier, the developer carrier having a resin coating layer on the surface S-2 to S-17 were produced. Regarding the charge polarity of the resin layer, as in Developer Production Example 1 of the developer carrier, a solution excluding components other than the resin was prepared, and the triboelectric charge polarity with the iron powder was measured after bar coating on the SUS plate. did.
[0182]
[Table 1]

[0183]
[Table 2]

[0184]
[Table 3]

[0185]
[Table 4]

[0186]
[Developer Production Example 1]
Styrene 68.5 parts
20 parts 2-ethylhexyl acrylate
10 parts monobutyl maleate
1.5 parts of divinylbenzene
Benzoyl peroxide 1 part
0.5 part of di-tert-butylperoxy-2-ethylhexanoate
200 parts of water in which 0.8 part of polyvinyl alcohol partially saponified product was dissolved was added to the above mixture and vigorously stirred to obtain a suspension dispersion. Furthermore, 50 parts of water was added, and the above suspension dispersion was added to a reactor purged with nitrogen, followed by suspension polymerization reaction at a reaction temperature of 80 ° C. for 9 hours. After completion of the reaction, it was washed with water, dehydrated and dried to obtain a vinyl resin (1).
[0187]
100 parts of the above vinyl resin (1)
90 parts of magnetite
Azo-based iron complex compound (negatively chargeable charge control agent) 2 parts
Low molecular weight ethylene-propylene copolymer 3 parts
The above mixture was kneaded with a biaxial kneading extruder heated to 130 ° C. After cooling the obtained kneaded product, it is coarsely pulverized with a hammer mill, the coarsely pulverized product is finely pulverized using a fine pulverizer using a jet stream, and the resulting finely pulverized powder is subjected to a Coanda effect. Ultrafine powder and coarse powder were classified and removed at the same time by a division classifier to obtain toner particles having a weight average particle diameter (D4) of 7.3 μm.
[0188]
To 100 parts of the toner particles, negatively charged hydrophobic silica fine powder (BET specific surface area: 300 m) treated with hexamethyldisilazane and dimethyl silicone oil.²/ G) and 1.5 parts of strontium titanate were added and mixed with a Henschel mixer to obtain a one-component negatively chargeable magnetic developer (toner 1) used in the present invention.
[0189]
[Example 1]
A magnet roller was inserted into the developer carrier S-1 described above, and flanges were attached to both ends. This developer carrier S-1 is incorporated into a developing unit of a Canon digital copying machine IR2000 (230V machine specification) using an OPC drum as an electrostatic latent image carrier, and the above toner 1 is used for 1 sheet / 10 seconds. 50,000 images were output in the intermittent mode. Image evaluation was performed at normal temperature and normal humidity environment (23 ° C., 50% RH; N / N), low temperature and low humidity environment (15 ° C., 10% RH; L / L), and high temperature and high humidity environment (32 ° C., 85% RH; H / H). The outline of the developing device is as shown in FIG. 6, and an elastic blade made of urethane rubber was used as the developer layer thickness regulating member. As a result of the image evaluation, as shown in Table 5, good developability was obtained from beginning to end under any environment. Evaluation methods and evaluation criteria are as follows.
[0190]
(1) Image density
The copy image density of a 5 mmφ circle on the test chart with an image ratio of 5.5% was measured for reflection density with a reflection densitometer RD918 (manufactured by Macbeth), and the average value of 10 points was taken as the image density.
[0191]
(2) fog
Measure the reflectivity of the solid white image in the proper image, measure the reflectivity of the unused transfer paper, and fog (the worst value of the reflectivity of the solid white image−the average value of the reflectivity of the unused transfer paper). The evaluation results are shown by the following indices. (However, the reflectance was measured at 10 points at random.) The reflectance was measured with TC-6DS (manufactured by Tokyo Denshoku).
A: 1.0% or less (fogging is not visually recognized)
B: 1.0 to 2.0% (Fog is not recognized unless watched)
C: 2.0 to 3.0% (although there is fog, there is no practical problem)
D: 3.0% or more (fogging is conspicuous NG level)
[0192]
(3) Sleeve ghost
The development sleeve that developed the image where the solid white portion and the solid black portion are adjacent to each other comes to the development position at the next rotation of the development sleeve, and develops the halftone image, so that the difference in density appears on the halftone image. Was visually evaluated based on the following criteria.
A: No difference in shading is observed.
B: A slight shading difference is observed.
C: Practical use is possible although there is a slight difference in shading.
D: The difference in light and shade, which is a problem in practical use, appears for one or more rounds of the sleeve.
[0193]
(4) Blotch (defective image)
Evaluation with reference to various images such as solid black, halftone and line images, and visual observation of defective toner coat on the sleeve such as wavy unevenness and blotch (spotted unevenness) on the developing sleeve The results were evaluated based on the following criteria.
A: Neither image nor sleeve can be confirmed at all.
B: Although it can be confirmed slightly on the sleeve, it can hardly be confirmed on the image.
C: Although it can be confirmed with a halftone image or a solid black image, it can be used practically.
D: An image defect that is a practical problem in the entire solid black image can be confirmed.
E: Image defects that are practically problematic can be confirmed on solid white images.
[0194]
(5) Halftone uniformity (white stripes, white belt)
In particular, the following criteria were evaluated for linear and strip-like streaks that occur in the halftone and run in the image traveling direction.
A: Neither image nor sleeve can be confirmed at all.
B: Level that can be confirmed with halftone, but no problem with solid black.
C: Difference in density can be confirmed even with solid black images, but practical use is possible
D: The density difference which is a practical problem in the whole solid black image is conspicuous.
E: An image having a low density and a large amount of streaks.
[0195]
(6) Image quality
A: A clear image that does not scatter even when viewed with a magnifying glass having a magnification of 10 times.
B: A clear image as long as it is visually observed.
C: Slight scattering is observed but there is no practical problem.
D: Character blurring is noticeable in addition to scattering.
[0196]
(7) Abrasion resistance of resin coating layer
The centerline average roughness (Ra) of the surface of the developer carrier before and after the endurance and the thickness of the resin coating layer were measured.
[0197]
(8) Resistant resistance of resin coating layer
The surface of the developer carrying member after durability was observed at about 200 times using an ultra-deep shape measuring microscope manufactured by KEYENCE, and the degree of toner contamination was evaluated based on the following criteria.
A: Only minor contamination is observed.
B: Some contamination is observed.
C: Contamination is partially observed.
D: Significant contamination is observed.
[0198]
[Examples 2 to 10 and Comparative Examples 1 to 7]
Image evaluation was performed by the same evaluation method as in Example 1 using developer carriers S-1 to S-17. The results are listed in Tables 5 and 6.
[0199]
[Table 5]

[0200]
[Table 6]

[0201]
[Production Examples 11-15 and Comparative Production Examples 8-10]
After preparing a coating liquid having a solid content adjusted to 35% with methanol in the same manner as in Production Example 1 of the developer carrier, the developer carrier having a resin coating layer on the surface was prepared according to the formulation described in Table 7. S-18 to S-25 were produced. However, as the sleeve tube, a cylindrical aluminum tube having an outer diameter of 24.5 mmφ and a center line average roughness Ra = 0.3 μm was used. Regarding the charging polarity of the resin layer, as in Developer Example (Development Sleeve) Production Example 1, a solution excluding components other than resin was prepared, and after bar coating on a SUS plate, friction with iron powder was made. The charging polarity was measured.
[0202]
[Developer Production Example 2]
Ethylene oxide-added bisphenol A 33 mol%
Propylene oxide addition bisphenol A 24 mol%
26 mol% terephthalic acid
n-dodecenyl succinic acid 12 mol%
Trimellitic acid 5 mol%
The above raw materials are charged into a 5-liter four-necked flask, a reflux condenser, a water separator, N₂Attach a gas inlet tube, thermometer, and stirrer, and put N in the flask.₂While introducing a gas, a condensation polymerization reaction was carried out at 180 ° C. After the reaction was completed, the polymer was washed with water, dehydrated and dried to obtain a polyester resin (2).
[0203]
100 parts of the above polyester resin (2)
90 parts of magnetite
Azo-based iron complex compound (negatively chargeable charge control agent) 2 parts
Fischer-Tropsch wax 5 parts
Using the above materials, toner particles having a weight average particle diameter (D4) of 6.3 μm were obtained in the same manner as in Developer Production Example 1.
[0204]
Negatively chargeable hydrophobic silica fine powder (BET specific surface area: 300 m) treated with hexamethyldisilazane on 100 parts of the toner particles²/ G) and 1.2 parts of strontium titanate were added and mixed with a Henschel mixer to obtain a one-component negatively chargeable magnetic developer (toner 2) used in the present invention.
[0205]
[Examples 11 to 15 and Comparative Examples 8 to 10]
Magnet rollers were inserted into the developer carriers S-18 to S-25 described above, and flanges were attached to both ends. This developer carrying member was incorporated into a developing unit of a Canon digital copying machine IR6000 using an amorphous silicon drum as an electrostatic latent image carrying member, and 100,000 images were printed in continuous mode using the toner 2. . Image evaluation was performed at normal temperature and normal humidity environment (23 ° C., 50% RH; N / N), low temperature and low humidity environment (15 ° C., 10% RH; L / L), and high temperature and high humidity environment (32 ° C., 85% RH; H / H). The outline of the developing device is as shown in FIG. 5, and a magnetic blade was used as the developer layer thickness regulating member. The results of image evaluation are listed in Table 8.
[0206]
[Production Examples 16 to 20 and Comparative Production Examples 11 to 13 of Developer Carrier]
According to the formulation described in Table 7, after preparing a coating liquid having a solid content adjusted to 35% with methanol in the same manner as in Production Example 1 of the developer carrier, the developer carrier having a resin coating layer on the surface S-26 to S-33 were produced. However, as the sleeve tube, a cylindrical aluminum tube having an outer diameter of 16 mmφ and a center line average roughness Ra = 0.2 μm was used. Regarding the charge polarity of the resin layer, as in Developer Example (Development Sleeve) Production Example 1, a solution excluding components other than the resin was prepared, and after bar coating on the SUS plate, friction with iron powder was made. The charging polarity was measured.
[0207]
[Developer Production Example 3]
In a 4-liter flask for 2 liters equipped with a high-speed stirring device TK-homomixer, 880 parts of ion-exchanged water and 0.1 mol / liter-Na_ThreePO_Four450 parts of an aqueous solution was added, the rotation speed was adjusted to 12000 rpm, and the mixture was heated to 58 ° C. Here 1.0 mol / liter-CaCl₂Gradually add 68 parts of an aqueous solution, and add a minute water-insoluble dispersant Ca_Three(PO_Four)₂A dispersion medium system containing was prepared.
[0208]
On the other hand, the dispersoid system is
170 parts of styrene monomer
40 parts of n-butyl acrylate monomer
C. I. Pigment Blue 15: 3 14 parts
16 parts of saturated polyester resin
(A product obtained by mixing terephthalic acid and ethylene oxide-added bisphenol A at a molar ratio of 550, followed by condensation polymerization)
Di-tert-butylsalicylic acid chromium compound (negatively chargeable charge control agent) 2 parts
20 parts of ester wax
The mixture was dispersed using an attritor for 3 hours, and then 10 parts of 2,2'-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added to obtain a dispersion. This was put into the dispersion medium and granulated for 12 minutes while maintaining the rotation speed. Thereafter, the high-speed stirrer was changed to a propeller stirring blade, the internal temperature was raised to 80 ° C., and the polymerization was continued at 50 rpm for 10 hours. After completion of the polymerization, the slurry was cooled and diluted hydrochloric acid was added to remove the dispersant. Further, the toner was washed and dried to obtain cyan toner particles. The cyan toner had a weight average particle diameter (D4) of 7.3 μm. Negatively chargeable hydrophobic silica fine powder (BET specific surface area: 300 m) subjected to hexamethyldisilazane treatment on 100 parts of the toner particles.²/ G) and 1.3 parts of strontium titanate were added and mixed with a Henschel mixer. This developer is toner 3.
[0209]
[Examples 16 to 20 and Comparative Examples 11 to 13]
The developer carriers S-26 to S-33 are incorporated into a cyan toner developer of a modified color laser beam printer LBP2030 manufactured by Canon using an OPC drum as an electrostatic latent image carrier, and the toner 3 is continuously used. 30,000 images were printed out in the mode. Image evaluation was performed at normal temperature and normal humidity environment (23 ° C., 50% RH; N / N), low temperature and low humidity environment (15 ° C., 10% RH; L / L), and high temperature and high humidity environment (32 ° C., 85% RH; H / H). The outline of the developing device is a modification of the one shown in FIG. 6 for a non-magnetic developer. As a developer layer thickness regulating member, a polyamide having a Shore D hardness of 40 degrees on a phosphor bronze thin plate is used. An elastic regulation member modified by providing a polyether elastomer by injection molding was used. The results of image evaluation are listed in Table 9.
[0210]
[Table 7]

[0211]
[Table 8]

[0212]
[Table 9]

[0213]
【The invention's effect】
As described above in detail, according to the present invention, problems such as density reduction, image density unevenness, sleeve ghosting and fogging do not occur in any environment, and there is no uneven density and image density is uniform. It is possible to provide a developer carrier, a developing device, and a process cartridge that can stably obtain a high-definition image.
[0214]
Further, according to the present invention, the toner adhesion to the surface of the developer carrying member, which is seen when using a toner having a small particle diameter or a spherical toner, is reduced. It is possible to provide a developer carrier, a developing device, and a process cartridge that can provide sufficient charge.
[0215]
Furthermore, according to the present invention, there is provided a developer carrier, a developing device, and a process cartridge that are resistant to deterioration of the resin coating layer on the surface of the developer carrier due to long-term durability, have high durability, and provide a stable image quality throughout. It becomes possible to do.
[0216]
Furthermore, according to the present invention, a high and uniform charge is imparted to the developer on the developer carrying member even in continuous copying over a long period of time, and a stable charge is always imparted without the occurrence of a charge-up phenomenon. It is possible to provide a developer carrying member, a developing device, and a process cartridge that can obtain a high-quality image that has a reduced image density and that is uniform and free from uneven density and fog.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a partial cross section of an embodiment of a developer carrying member of the present invention.
FIG. 2 is a schematic view showing a partial cross section of an embodiment of the developer carrying member of the present invention.
FIG. 3 is a schematic diagram showing a partial cross section of an embodiment of the developer carrying member of the present invention.
FIG. 4 is a schematic view showing a partial cross section of an embodiment of the developer carrying member of the present invention.
FIG. 5 is a schematic explanatory diagram of an embodiment of a developing device of the present invention.
FIG. 6 is a schematic explanatory diagram of an embodiment of a developing device of the present invention.
FIG. 7 is a schematic explanatory diagram of one embodiment of a process cartridge of the present invention.
FIG. 8 is a schematic explanatory view of a surface charge amount measuring apparatus for measuring the charge polarity of a binder resin forming a resin coating layer of a developer carrying member of the present invention.
[Explanation of symbols]
1 Resin coating layer
2 Base
3 Magnet roller
11 Graphitized particles
12 Binder resin
13 Conductive agent
14 Solid lubricant
15 Spherical particles
51 Photosensitive drum
52 Magnetic restriction blade
53 Developer Container
54 Partition members
55 Stirring conveying member
56 Metal cylindrical tube
57 Resin coating layer
58 Development sleeve (developer carrier)
59 Magnet
60 Developing roller
61 Stirrer
62 Developer supply member
63 Development bias power supply
64 Room 1
65 Room 2
67 Elastic regulating blade
70 Process cartridge
71 Developing means
72 Cleaning means
72a Cleaning blade
73 Contact charging means
81 Iron powder
82 Dropper
83 samples
84 Receptor
85 Electrometer
86 condenser

Claims (4)

For developing and visualizing a latent image formed on a latent image carrier with a one-component negatively chargeable magnetic developer or a one-component negatively charged nonmagnetic developer conveyed and supported on the surface of the developer carrier. A developer carrier used in the developing device,
It has a resin coating layer on the surface of a cylindrical or columnar metal substrate,
The resin coating layer is obtained by dispersing graphitized particles in a resin layer in which the triboelectric charge polarity with respect to iron powder is positive.
The graphitized particles have a graphitization degree p (002) of 0.22 or more and 0.93 or less, and are obtained by heat-treating mesocarbon microbeads or mesophase pitch at 2300 to 3150 ° C. in an inert atmosphere. And
The developer-carrying member, wherein the resin coating layer contains the graphitized particles in an amount of 25 wt% to 45 wt% with respect to the resin component in the resin coating layer.   2. The developer carrying member according to claim 1, wherein the graphitized particles have a number average particle diameter of 0.5 μm or more and 25 μm or less. A developer container containing a developer;
A developer carrier for carrying the developer contained in the developer container and transporting it to the development area, and a developer layer for regulating the layer thickness of the developer carried on the developer carrier A developing device having at least a thickness regulating member,
The developer is a one-component negatively chargeable magnetic developer or a one-component negatively chargeable nonmagnetic developer,
A developing device developing agent carrying member, characterized in that it is a developer carrying member according to claim 1 or 2. The electrostatic latent image formed on the latent image carrier is visualized as a developer image with a developer, and the visualized developer image is transferred to a transfer material to form an image on the image forming apparatus main body. A process cartridge that is detachably attached to the cartridge,
A latent image carrier for carrying an electrostatic latent image;
Charging means for charging the latent image carrier;
The electrostatic latent image formed on the latent image bearing member is visualized as a developer image by developing with a developer, and after the developer image is transferred to a transfer material as a recording medium, And at least developing means for recovering the developer remaining on the latent image carrier,
The developing means has a developer container containing a developer, and a developer carrier for carrying the developer contained in the developer container and transporting the developer to the development area. The latent image carrier and the developing means are integrated,
The developer carrier is a one-component negatively chargeable magnetic developer or a one-component negatively chargeable nonmagnetic developer, and the developer carrier is the developer carrier according to claim 1 or 2. Process cartridge characterized by being.

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