JP2004212561A - Electrophotographic photoreceptor, process cartridge, and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor excellent in electrophotographic properties, image stability after repeated use and wear resistance by using a coating material for a surface layer in which inorganic fine particles are reduced in particle diameter and liquid stability is maintained, and to provide a process cartridge with the electrophotographic photoreceptor, and an electrophotographic apparatus. <P>SOLUTION: The electrophotographic photoreceptor contains inorganic fine particles having a volume average particle diameter of 0.01-5.0μm in a surface layer. Inorganic fine particles used for the surface layer are pressurized with a solvent to a high pressure, and by liquid collision under the high pressure, the inorganic fine particles are pulverized and dispersed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００４６】
［実施分散液３］
疎水化シリカパウダー（商品名：ＫＭＰＸ−１００、平均粒径０．１μｍ、信越化学工業（株）製）２０部と熱可塑性樹脂としてポリカーボネート樹脂（商品名：ユーピロンＺ４００、三菱瓦斯化学（株）製）２０部をモノクロロベンゼン２００部に混合し、撹拌した以外は、実施分散液１と同様に分散し、粒度分布を測定した（更に高圧処理を続けたが５回以降、粒径に変化がなかった）。結果を表２に示す。
【００４７】
［比較分散液３］
疎水化シリカパウダー（商品名：ＫＭＰＸ−１００、平均粒径０．１μｍ、信越化学工業（株）製）２０部と熱可塑性樹脂としてポリカーボネート樹脂（商品名：ユーピロンＺ４００、三菱瓦斯化学（株）製）２０部をモノクロロベンゼン２００部に混合し、撹拌した以外は、比較分散液１と同様に分散し、粒度分布を測定した（更に超音波分散を続けたが１２０分以降、粒径に変化がなかった）。結果を表２に示す。
【００４８】
［実施分散液４］
実施分散液３の分散液を２週間静置保存した以外は、実施分散液１の測定条件に従い粒度分布を測定した。結果を表２に示す（ただし高圧処理５回品の２週間後の粒径のみ表記）。
【００４９】
［比較分散液４］
比較分散液３の分散液を２週間静置保存した以外は、実施分散液１との測定条件に従い粒度分布を測定した。結果を表２に示す（ただし超音波分散１２０分品の２週間後の粒径のみ表記）。
【００５０】
【表２】

【００５１】
［実施分散液５］
実施分散液３において熱可塑性樹脂を以下に示される構造式（１）で示されるポリアリレート樹脂（重量平均分子量：１００，０００）に代えた以外は全て同じで、分散し、粒度分布を測定した。結果を表３に示す。なお表３に記載の実施分散液の平均粒径は５回品の粒径を記載する。
【００５２】
【化１】

【００５３】
［比較分散液５］
比較分散液３において熱可塑性樹脂を式（１）で示されるポリアリレート樹脂（に代えた以外は全て同じで、分散し、粒度分布を測定した。結果を表３に示す。なお表３に記載の比較分散液の平均粒径は１２０分品の粒径を記載する。
【００５４】
［実施分散液６、７］
実施分散液５において疎水化シリカパウダーをそれぞれ疎水化シリカパウダー（商品名：Ｘ−１２０、平均粒径０．０２μｍ、信越化学工業（株）製）、シリカドール（商品名：３０Ｇ−１００、平均粒径０．１μｍ、日本化学工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００５５】
［比較分散液６、７］
比較分散液５において疎水化シリカパウダーをそれぞれ疎水化シリカパウダー（商品名：Ｘ−１２０、平均粒径０．０２μｍ、信越化学工業（株）製）、シリカドール（商品名：３０Ｇ−１００、平均粒径０．１μｍ、日本化学工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００５６】
［実施分散液８、９］
実施分散液５において疎水化シリカパウダーをそれぞれアルミナ（商品名：ＬＳ−２３５、平均粒径０．１μｍ、日本軽金属（株）製）、酸化亜鉛（商品名：ＦＩＮＥＸ−２５ＬＰ、平均粒径０．１μｍ、堺化学工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００５７】
［比較分散液８、９］
比較分散液５において疎水化シリカパウダーそれぞれアルミナ（商品名：ＬＳ−２３５、平均粒径０．１μｍ、日本軽金属（株）製）、酸化亜鉛（商品名：ＦＩＮＥＸ−２５ＬＰ、平均粒径０．１μｍ、堺化学工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００５８】
［実施分散液１０、１１］
実施分散液５において疎水化シリカパウダー（商品名：ＫＭＰ−１１０、平均粒径１．９μｍ、信越化学工業（株）製、）に代えた以外は全て同じで、結果を表３に示す。
【００５９】
［比較分散液１０］
比較分散液５において疎水化シリカパウダーを疎水化シリカパウダー（商品名：ＫＭＰ−１１０、平均粒径１．９μｍ、信越化学工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００６０】
［実施分散液１１］
実施分散液５において熱可塑性樹脂を以下に示される構造式（２）（重量平均分子量：７２，０００）に代えた以外は全て同じで、結果を表３に示す。
【００６１】
【化２】

【００６２】
［比較分散液１１］
比較分散液５において熱可塑性樹脂を式（２）で示されるポリカーボネ−ト樹脂に代えた以外は全て同じで、結果を表３に示す。
【００６３】
［実施分散液１２］
実施分散液５において熱可塑性樹脂を以下に示される構造式（３）（重量平均分子量：６９，０００）に代えた以外は全て同じで、結果を表３に示す。
【００６４】
【化３】

【００６５】
［比較分散液１２］
比較分散液５において熱可塑性樹脂を式（３）で示される樹脂（に代えた以外は全て同じで、結果を表３に示す（。
【００６６】
［比較分散液１３］
実施分散液５において疎水化シリカパウダーを合成シリカ（商品名：アエロジル３００ＣＦ、平均粒径０．００７μｍ、土屋カオリン工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００６７】
［比較分散液１４］
実施分散液５において疎水化シリカパウダーをアルミナ（商品名：ＡＬ４３Ｍ、平均粒径２．２μｍ、土屋カオリン工業（株）製）に代えた以外は全て同じで、結果を表３に示す。
【００６８】
【表３】

【００６９】
比較分散液の平均粒子径は実施分散液に比べ、高い。また比較分散液は安定性が悪い。更に比較分散液１３においては分散過程において、多量の気砲が発生し、その気砲が圧力の低下を招き、分散不良になった。さらに分散３時間後にはゲル状になってしまった。また比較分散液１４においては他の液と比較して最も沈降の度合いが大きいということがわかった。
【００７０】
［実施例１］
直径３０ｍｍ×長さ３５７．５ｍｍのアルミニウムシリンダーを支持体とし、それに、以下の材料より構成される塗料を支持体上に浸漬コーティング法で塗布し１４０℃で３０分熱硬化して１５μｍの導電層を形成した。
【００７１】
導電性顔料：ＳｎＯ_２コート処理硫酸バリウム １０部
抵抗調節用顔料：酸化チタン ２部
バインダー樹脂：フェノール樹脂 ６部
レベリング材：シリコーンオイル ０．００１部
溶剤：メタノール、メトキシプロパノール０．２／０．８ ２０部
【００７２】
次に、この上にＮ−メトキシメチル化ナイロン３部及び共重合ナイロン３部をメタノール６５部及びｎ−ブタノール３０部の混合溶媒に溶解した溶液を浸漬コーティング法で塗布し、１００℃で１０分乾燥して、膜厚が０．５μｍの中間層を形成した。
【００７３】
次に、ＣｕＫα特性Ｘ線回折におけるブラッグ角２θ±０．２°の９．０°、１４．２°、２３．９°及び２７．１°に強いピークを有するオキシチタニウムフタロシアニン（ＴｉＯＰｃ）４部とポリビニルブチラール（商品名：エスレックＢＭ２、積水化学（株）製）２部及びシクロヘキサノン６０部を直径１ｍｍガラスビーズを用いたサンドミル装置で４時間分散した後、酢酸エチル１００部を加えて電荷発生層用分散液を調製した。これを浸漬コーティング法で塗布し、１００℃で１０分乾燥して、膜厚が０．２μｍの電荷発生層を形成した。
【００７４】
次に、実施分散液１で得られた疎水化シリカパウダー分散液（高圧処理５回品）１５０部にバインダー樹脂としてポリカーボネート樹脂（商品名：ユーピロンＺ４００、三菱瓦斯化学（株）製）５０部をモノクロロベンゼン８０部とジクロロメタン４０部と共に加え、溶解させ、この溶解液に下記構造式で示される電荷輸送材料の質量比が（４）：（５）＝８：１となるように合計４０部
下記構造式（４）で示されるトリアリールアミン化合物
【００７５】
【化４】

下記構造式（５）で示されるスチルベン化合物
【００７６】
【化５】

を溶解させ電荷輸送層用塗料とし、前記電荷発生層上に浸漬コーティング法で塗布し、１２０℃で１時間乾燥して、膜厚が２９μｍの電荷輸送層を形成し、電子写真感光体とした。
【００７７】
［比較例１］
疎水化シリカパウダー分散液として比較分散液１で示した中で１２０分の条件の分散液を用いた以外は、実施例１と全く同様な感光体を作成した。
【００７８】
［実施例２］
実施例１で得られた電荷輸送層用塗料を２週間静置保存したものを使用した以外は、実施例１と全く同様な感光体を作成した。
【００７９】
［比較例２］
比較例１で得られた電荷輸送層用塗料を２週間静置保存したものを使用した以外は、実施例１と全く同様な感光体を作成した。
【００８０】
［比較例３］
実施例１の電荷輸送層用塗料において、実施分散液１を除き、モノクロロベンゼン１８０部とジクロロメタン８０部に代えた以外は、実施例１と全く同様な感光体を作成した。
【００８１】
このようにして得られた実施例１、２の感光体及び比較例１、２、３の感光体について複写機「ＧＰ−４０」（キヤノン（株）製）を用いて評価した。評価方法を以下に示し、評価結果を表４に示す。
【００８２】
作成した電子写真感光体をＡＣ電圧を重畳したローラー接触帯電手段（ＡＣ／ＤＣローラー接触帯電手段）を有する複写機でプロセススピード２１０ｍｍ／ｓｅｃを有する「ＧＰ−４０」（キヤノン（株）製）に取り付け、温度２３℃、湿度５０％ＲＨの常温常湿環境（Ｎ／Ｎ）下で測定した。なおＧＰ−４０には、電子写真感光体の電位特性を測定するため、現像位置にプローブを取り付けた電位測定冶具を用いて測定した。 『電位』は、帯電電位Ｖｄ、感度ＥΔ５００及び残留電位Ｖｒを初期と連続通紙耐久４０，０００枚後に測定したものである。なお帯電電位Ｖｄは絶対値が大きい程帯電能がよいことを示し、感度ＥΔ５００は−７００Ｖから−２００Ｖに電位を減衰させるのに必要な光量で、値が小さい程感度がよいことを示す。
【００８３】
『感光体欠陥』は、感光体表面の目視観察による疎水化シリカパウダーの凝集物を意味する。
【００８４】
『耐久削れ性』では連続通紙耐久４０，０００枚後の感光体削れ量を示す。なお膜厚の測定にはフィッシャー社製渦電流式膜厚測定機（パーマスコープタイプＥ１１１）を用いた。 『耐久画像』では４０，０００枚後の画像品位を示し、ハーフトーン画像上に現われる画像欠陥を目視により、評価した。なお画像欠陥の種類としては凝集物そのものによる画像欠陥、感光体の周方向に対して凝集物を起点とした傷による画像欠陥などが見られる場合がある。
【００８５】
画像はＡ４で、印字率４％の格子パターンとした。また、シーケンスはプリント１枚毎に１回停止する間欠モードとした。トナーがなくなったならば補給した。
【００８６】
【表４】

【００８７】
［実施例３、４］
実施分散液１で示した疎水化シリカパウダー分散液（高圧処理５回品）の量をそれぞれ７０部、１１０部に代えた以外は、実施例１と同様に電子写真感光体を作成し評価した。なお、実施例３〜実施例１３までの配合比を表．５にまた結果を表６に示す。
【００８８】
［実施例５］
電荷輸送層用バインダー樹脂を式（１）で示されるポリアリレート樹脂に代えた以外は、実施例１と同様に電子写真感光体を作成し評価した。
【００８９】
［実施例６］
実施分散液３で示した疎水化シリカパウダー分散液（高圧処理５回品）量を１６０部とし、更にポリカーボネート樹脂量を３５部に変えた以外は、実施例１と同様に電子写真感光体を作成し評価した。
【００９０】
［実施例７］
実施分散液５で示した疎水化シリカパウダー分散液（高圧処理５回品）量を１６０部とし、更に電荷輸送用バインダーを式（１）で示されるポリアリレート樹脂に代え、樹脂量を３５部に変えた以外は実施例１と同様に電子写真感光体を作成し評価した。
【００９１】
［実施例８〜１１］
電荷輸送層として、それぞれ実施分散液６、８、９、１０において得られた分散液（高圧処理５回品）と配合比、電荷輸送層用バインダーについては表５記載の通りに使用した以外は、実施例１と同様に電子写真感光体を作成し評価した。
【００９２】
［実施例１２］
実施分散液１１で示した疎水化シリカパウダー分散液（高圧処理５回品）量を１６０部とし、更に電荷輸送用バインダーとして構造式（３）で示されるバインダーに代え、樹脂量を３５部に変えた以外は、実施例１と同様に電子写真感光体を作成し評価した。
【００９３】
［実施例１３］
実施例１の電子写真感光体において電荷輸送層を変え、更に保護層を設けた。即ち、電荷輸送層としてポリカーボネート樹脂（商品名：ユーピロンＺ４００、三菱瓦斯化学（株）製）５０部と実施例１で示した電荷輸送材料４０部をモノクロロベンゼン２００部とジクロロメタン８０部と共に加え、溶解させ、電荷輸送層用塗料とし、浸漬コーティング法で塗布し、１２０℃で６０分間乾燥して、膜厚が２１μｍの電荷輸送層を設けた。
【００９４】
次に、保護層として実施分散液１で得られた疎水化シリカパウダー分散液（高圧処理５回品）２５部、電荷輸送層で用いた式（４）で示される電荷輸送材料４部、ポリカーボネート樹脂（商品名：ユーピロンＺ８００、三菱瓦斯化学（株）製）４部、モノクロロベンゼン２００部及びジクロルメタン２５０部を混合し、溶解して表面保護層用塗料とした。この塗料を上記電荷輸送層上に霧化塗布し、１２０℃で６０分間乾燥して、膜厚が５．０μｍの保護層を形成し、電子写真感光体を作成し、評価した。
【００９５】
［比較例４〜８］
電荷輸送層として、それぞれ比較分散液５、６、８、９、１３において得られた分散液（１２０分品）と配合比及び電荷輸送層用バインダーについては表５の通りに使用した以外は、実施例１と同様に電子写真感光体を作成し、評価した。その結果を表６に示す。
【００９６】
［比較例９］
実施例１３において、保護層を以下のように変更した。
【００９７】
すなわち保護層として比較分散液１を用いた以外は実施例１３と同様に作成し、評価した。
【００９８】
【表５】

【００９９】
【表６】

【０１００】
実施例は感光体は凝集物もなく、表面が平滑であり均一であった。さらに良好な電子写真特性を示し、かつ画質も良好であった。
【０１０１】
［実施例１４］
実施例１において、支持体を直径３０ｍｍ×長さ２６０．５ｍｍのアルミニウムシリンダーに代えた以外は、実施例１と同様に電子写真感光体を作製し、以下の評価機を用いて測定した以外は実施例１と同様である。
【０１０２】
・評価機
ＬＢＰ−ＳＸ（レーザービームプリンター）（キヤノン（株）製）
帯電方式：コロナ帯電
プロセススピード：４７ｍｍ／ｓｅｃ
クリーニングブレード：感光体に対する線圧を通常の１．４倍に設定
暗部電位Ｖｄ：−５００
レーザー光量：波長８０２ｎｍのレーザー光を照射したときに明部電位Ｖｌが−１００Ｖとなる光量に設定
なお、現像位置にプローブを取り付けた電位測定治具を用いて電子写真特性を測定した。
【０１０３】
また、耐久枚数を５，０００枚とした。
【０１０４】
以下、表７に結果を示す。
【０１０５】
［実施例１５］
実施例１における電子写真感光体において、以下の評価機を用いて測定した以外は、実施例１と同様に評価した。
【０１０６】
・評価機
ＮＰ−６０３０（普通紙複写機）（キヤノン（株）製）
帯電方式：直流電圧印加（ＤＣ帯電）
プロセススピード：２００（ｍｍ／ｓｅｃ）
クリーニングブレード：感光体に対する線圧を通常の１．４倍に設定
暗部電位Ｖｄ：−４００
レーザー光量：明部電位Ｖｌが−７０Ｖとなる光量に設定
なお、現像位置にプローブを取り付けた電位測定治具を用いて電子写真特性を測定した。
【０１０７】
また、耐久枚数は４０，０００枚とした。
【０１０８】
以下、表７に結果を示す。
【０１０９】
［比較例１０］
比較例１において、支持体を直径３０ｍｍ×長さ２６０．５ｍｍのアルミニウムシリンダーに代えた以外は比較例１と同様に電子写真感光体を作製し、実施例１４と同様に測定した。
【０１１０】
［比較例１１］
比較例１における電子写真感光体において、実施例１５と同様に測定した。
【０１１１】
【表７】

【０１１２】
以上本発明の実施例について説明したが、本発明の好適な実施の態様を以下のとおり列挙する。
【０１１３】
［実施態様１］
表面層に体積平均粒径０．０１〜２．０μｍの無機微粒子を含有する電子写真感光体において、該表面層に用いられる無機微粒子が、溶剤と共に高圧状態に昇圧され、該高圧の液衝突により粉砕及び分散されたものであることを特徴とする電子写真感光体。
【０１１４】
［実施態様２］
前記昇圧、粉砕及び分散が、前記無機微粒子及び溶剤を微細な流路に圧送し、該微細な流路での高圧の液衝突により行われる実施態様１に記載の電子写真感光体。
【０１１５】
［実施態様３］
前記昇圧、粉砕及び分散が、前記無機微粒子及び溶剤を微細な流路に圧送し、該流路の吐出口直後の障害壁への液衝突により行われる実施態様１に記載の電子写真感光体。
【０１１６】
［実施態様４］
表面層に体積平均粒径０．０１〜２．０μｍの無機微粒子を含有する電子写真感光体において、該表面層に用いられる無機微粒子が、熱可塑性樹脂及び溶剤と共に高圧状態に昇圧され、該高圧の液衝突により粉砕及び分散されたものであることを特徴とする電子写真感光体。
【０１１７】
［実施態様５］
前記昇圧、粉砕及び分散が、前記無機微粒子、熱可塑性樹脂及び溶剤を微細な流路に圧送し、該微細な流路での高圧の液衝突により行われる実施態様４に記載の電子写真感光体。
【０１１８】
［実施態様６］
前記昇圧、粉砕及び分散が、前記無機微粒子、熱可塑性樹脂及び溶剤を微細な流路に圧送し、該流路の吐出口直後の障害壁への液衝突により行われる実施態様４に記載の電子写真感光体。
【０１１９】
［実施態様７］
前記感光体の表面層が電荷輸送層である実施態様１乃至６のいずれかに記載の電子写真感光体。
【０１２０】
［実施態様８］
前記熱可塑性樹脂がポリカーボネート樹脂あるいはポリアリレート樹脂である実施態様４乃至７のいずれかに記載の電子写真感光体。
【０１２１】
［実施態様９］
前記無機微粒子がシリカ微粒子である実施態様１乃至８のいずれかに記載の電子写真感光体。
【０１２２】
［実施態様１０］
前記無機微粒子が疎水化されたシリカ微粒子である実施態様１乃至９のいずれかに記載の電子写真感光体。
【０１２３】
［実施態様１１］
接触帯電方式に使用される実施態様１乃至１０のいずれかに記載の電子写真感光体。
【０１２４】
【発明の効果】
本発明によれば、高圧状態に昇圧され、該高圧の液衝突による粉砕及び分散により、無機微粒子を微小径に分散でき、かつ長期にわたり液安定性が維持できる表面層用塗料が得られ、この表面層塗料を用いた電子写真感光体表面は、凝集物のない均一な表面を形成し、かつ電気的感度も良好で帯電特性、感度、残留電位の繰り返し電位安定性が優れ、更には表面滑り性及び耐傷性、耐摩耗性の優れた電子写真感光体を得、画質画像欠陥のない優れた画像を提供することが可能である。
【図面の簡単な説明】
【図１】本発明に用いる液衝突型高速分散機の概略構成を示す図である。
【図２】本発明に用いる液衝突型高速分散機における液衝突治具の外観図である。
【図３】本発明の電子写真感光体を有するプロセスカートリッジを有する電子写真装置の概略構成を示す図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus. Specifically, in an electrophotographic photoreceptor containing inorganic fine particles, particularly inorganic fine particles and a thermoplastic resin in the surface layer, the surface layer in which the inorganic fine particles are reduced in particle size by a specific dispersion method and the liquid stability is maintained The present invention relates to an electrophotographic photoreceptor having excellent electrophotographic characteristics and image stability due to repeated use and excellent abrasion resistance by using a coating material, and a process cartridge and an electrophotographic apparatus having the electrophotographic photoreceptor.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as a material used for an electrophotographic photoreceptor, an organic photoconductive substance has been widely used because of its advantages such as non-pollution and high productivity. These electrophotographic photoconductors are often used as function-separated photoconductors in which a charge generation layer and a charge transport layer are laminated in order to satisfy both electrical and mechanical properties.
[0003]
On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the applied electrophotographic process.
[0004]
In particular, since various electrical and mechanical external forces such as charging, exposure, toner development, transfer to paper, and cleaning are directly applied to the surface layer of the photoreceptor used repeatedly, durability is required for them. . Specifically, a reduction in sensitivity, a reduction in charging ability, an increase in residual potential, and durability against abrasion and scratches on the surface are required. In addition, it is required that the transferability of the toner image and the cleaning property of the residual toner after transfer are excellent, and for that purpose, it is necessary that the surface energy is low and the slip property is high, and this is used repeatedly. Sometimes it is desired that the performance does not decrease.
[0005]
It has been difficult for an electrophotographic photosensitive member using an organic photoconductive material to satisfy the above-mentioned characteristics, particularly durability.
[0006]
The surface layer of an electrophotographic photosensitive member using an organic photoconductive substance is generally a thin resin layer, and the characteristics of the resin are very important. In recent years, acrylic resins, polycarbonate resins, polyarylate resins, and the like have been put to practical use as resins that satisfy the above-described various properties to some extent. However, not all of the above-mentioned properties are satisfied by these resins, and it is hard to say that the hardness of the resins is sufficiently high particularly for further increasing the durability. That is, even when the resin is used as a resin for the surface layer, the surface layer may be worn, scratched, or deteriorated in slipperiness with repeated use. In addition, due to recent demand for higher sensitivity, a relatively large amount of a low molecular weight component such as a charge transporting substance is often added, and a resin having more durability is desired.
[0007]
Specifically, fluorine-containing resin fine particles (for example, see Patent Literatures 1 to 4) and inorganic fine particles (for example, Patent Literature 5) as wear reducing agents for the purpose of reducing the friction coefficient and the surface energy of the photoreceptor surface. To 11) have been proposed. However, if the fluorine-containing resin fine particles agglomerate or settle in the surface layer paint, they become non-uniform in the photoreceptor surface layer, resulting in a difference in abrasion amount, a difference in cleaning performance, etc., which causes image defects. . As a countermeasure, it is possible to add a surfactant or the like as a dispersing aid in order to improve the dispersion stability of the fluorine-containing resin fine particles. It will be accompanied by a drop.
[0008]
On the other hand, as for the inorganic fine particles, hydrophobic particles of silica fine particles and zinc oxide do not require a dispersing aid, so that there is no problem that the electric potential characteristics are lowered by the aid. Further, by adding the inorganic fine particles to the surface layer, the surface hardness is increased and the external impact surrounding the photoreceptor is increased. Further, by using inorganic fine particles having a small particle size, higher image quality and higher durability due to an increase in surface hardness can be expected. However, by reducing the diameter, the total surface area of the fine particles increases, the cohesive force between the particles increases, and the liquid stability deteriorates. However, there are problems such as deterioration of image quality and image quality.
[0009]
In order to solve such a problem, a method for increasing the stability of a dispersion in a coating material has been attempted.
[0010]
However, as a means for dispersing powders and the like, ultrasonic dispersion, roll mill, ball mill, sand mill, attritor, and the like are known, but have advantages and disadvantages in dispersion efficiency and dispersion capacity, and are also the same. If the dispersing method is slightly changed in the dispersing means, problems may occur in the particle size and the liquid stability. Further, even when there is no such problem, there is a possibility that a problem such as a scratch may occur when the electrophotographic photosensitive member is used.
[0011]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 50-23231
[Patent Document 2]
JP-A-61-116362
[Patent Document 3]
JP-A-61-204633
[Patent Document 4]
JP-A-61-270768
[Patent Document 5]
JP-A-56-117245
[Patent Document 6]
JP-A-59-223443
[Patent Document 7]
JP 08-202062 A
[Patent Document 8]
JP 08-262756 A
[Patent Document 9]
JP 08-320588 A
[Patent Document 10]
JP 2002-131964 A
[Patent Document 11]
JP 2002-182409 A
[0012]
[Problems to be solved by the invention]
An object of the present invention is to provide a surface layer coating in which inorganic fine particles are reduced in particle size and liquid stability is maintained, so that electrophotographic characteristics and image stability due to repeated use are excellent, and scratch resistance and abrasion resistance are improved. An object of the present invention is to provide an excellent electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.
[0013]
[Means for Solving the Problems]
That is, the present invention provides an electrophotographic photosensitive member containing inorganic fine particles having a volume average particle diameter of 0.01 to 2.0 μm in a surface layer, wherein the inorganic fine particles used in the surface layer are pressurized together with a solvent to a high pressure state, An electrophotographic photoreceptor characterized by being pulverized and dispersed by the high-pressure liquid collision.
[0014]
Further, the present invention provides an electrophotographic photoreceptor containing inorganic fine particles having a volume average particle diameter of 0.01 to 2.0 μm in a surface layer, wherein the inorganic fine particles used in the surface layer are in a high pressure state together with a thermoplastic resin and a solvent. The electrophotographic photoreceptor is characterized in that it is pressurized and pulverized and dispersed by the high-pressure liquid collision.
[0015]
Further, the present invention is a process cartridge and an electrophotographic apparatus including the above electrophotographic photosensitive member.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
As means for pumping a fluid to a fine flow path in the present invention and pulverizing and dispersing an object to be dispersed by high-pressure liquid collision in the fine flow path, a high-pressure pump and a plurality of small diameter pipes connected to the high-pressure pump are used. And a jig machined so that the liquids collide with each other when the liquid is discharged from the orifice. In the present invention, the high pressure means the discharge amount of the high-pressure pump, It is generally determined from the pressure, orifice system and length, and the viscosity of the material to be dispersed, and is 50 to 1400 kgf / cm. ² (About 5,000 kPa to 140,000 kPa: 1 kgf / cm ² = 100 kPa). FIG. 1 shows a schematic example of such an apparatus. Briefly describing the apparatus with reference to FIG. 1, the material to be dispersed charged from the non-dispersed material charging container 31 is filled in the pipe during the suction-discharge process of the high-pressure pump 32. As the high-pressure pump, a pump using a hydraulic cylinder, a plunger pump, or the like is used. The object to be dispersed is pressure-fed to the liquid impingement jig 34 in the compression step of the pump, and moves in a jig having one or several orifices 37 (50 μm to 2 mm in diameter, 2 to 10 mm in length) in a high-pressure state. Liquid collision occurs. If necessary, the sample received in the sample receiving container 35 can be further charged into the non-dispersed material input container 31 to repeat the process until desired physical properties are obtained. Furthermore, it is also possible to control the temperature of the liquid in the pipe by a heat exchange system. In the drawing, reference numeral 33 denotes a high-pressure pipe, 36 denotes a pressure gauge, and 38 denotes a three-way valve. FIG. 2 shows an external view of the liquid collision jig 34.
[0017]
The inorganic fine particles used in the present invention include oxides such as silica, alumina, zinc oxide and zirconium oxide, nitrides such as carbon nitride, aluminum nitride and silicon nitride, carbides such as silicon carbide, strontium titanate and barium titanate. And the like. Preferably, silica is used. Examples of the silica particles include those obtained by finely pulverizing or spheroidizing natural silica or quartz, or performing hollow processing, and synthetic silica. These fine particles have a volume average particle size of 0.01 to 2.0 μm. When the particle diameter is larger than 2.0 μm, the surface layer (fine particle-containing layer) itself is brittle, and the intended improvement in durability is not sufficiently exhibited. In addition, the cleaning mechanism may be damaged due to the presence of large particles. Conversely, if the particle size is smaller than 0.01 μm, the dispersion liquid tends to be gelled, and when used as a charge transport coating liquid, it is difficult to prevent air bubbles mixed during dispersion, resulting in poor coating properties. Cause problems. Further, the hardness cannot be sufficiently improved, and the intended improvement in durability cannot be obtained.
[0018]
When the inorganic fine particles are hygroscopic, the electrical resistance of the surface of the photoreceptor decreases in a high humidity environment, which may cause image defects such as image bleeding. Therefore, the inorganic fine particles are preferably hydrophobic. In the case of hydrophilic inorganic fine particles, it is preferable to perform a hydrophobic treatment by a known method. The electric resistance required for the fine particles varies depending on the electric resistance required for the outermost surface layer. ⁸ It is preferable that the resistance is Ω · cm or more. If it is smaller than this, problems tend to occur in the charge retention of the photoconductor, image quality, and the like.
[0019]
In the electrophotographic photoreceptor manufacturing process, examples of the solvent to be used include chlorobenzene, tetrahydrofuran, 1,4-dioxane, toluene, xylene, and the like. A single solvent or a plurality of solvents may be used.
[0020]
Further, a thermoplastic resin is preferable as the resin added before the dispersion, and a polycarbonate resin or a polyarylate resin having a bisphenol A skeleton or a Z skeleton is more preferable.
[0021]
The resin used in the surface layer of the photoreceptor of the present invention is generally appropriately mixed during or after dispersion. Examples of such a resin include a polycarbonate resin having a bisphenol A skeleton, a polycarbonate having a bisphenol Z skeleton, other polycarbonate resins, a polyarylate resin having a bisphenol A skeleton, a polyarylate resin having a bisphenol Z skeleton, other polyarylate resins, and acrylic. Resins, styrene resins, acryl-styrene copolymer resins, polyester resins, polyurethane resins, polysulfone resins, etc., may be used alone or in combination with a plurality of resins.
[0022]
Further, a photosensitive material and additives such as a sensitizer and an antioxidant can be added to the surface layer of the photoreceptor of the present invention.
[0023]
Inorganic fine particles used for the surface layer of the photoreceptor of the present invention are pressurized to a high pressure state together with a solvent or together with a solvent and a thermoplastic resin, and in a surface layer paint using those crushed and dispersed by the high-pressure liquid collision, In addition, the diameter of the inorganic fine particles can be reduced, and the liquid stability can be maintained for a long time. In addition, the surface of the photoreceptor can contain the inorganic fine particles to an effective amount in a uniform dispersion state without aggregation or the like, and therefore, have an appropriate surface slip property, lubricity, scratch resistance, and wear resistance. it can.
[0024]
Hereinafter, the configuration of the electrophotographic photosensitive member used in the present invention will be described.
[0025]
The electrophotographic photoreceptor in the present invention may be a single-layer type in which the photosensitive layer contains a charge transport material and a charge generation material in the same layer, or may be a stacked type in which a charge transport layer and a charge generation layer are separated. In terms of electrophotographic characteristics, a laminated type is preferable.
[0026]
The support used in the present invention may be any support as long as it has electrical conductivity.For example, aluminum, copper, chromium, nickel, zinc, stainless and other metals formed into a drum or sheet, aluminum Examples thereof include those obtained by laminating a metal foil such as copper or copper on a plastic film, those obtained by depositing aluminum, indium oxide, tin oxide, or the like on a plastic film.
[0027]
When an image input such as LBP is a laser beam, a conductive layer may be provided for the purpose of preventing interference fringes due to scattering or covering a scratch on the support. This can be formed by dispersing a conductive powder such as carbon black or metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, more preferably 10 to 30 μm.
[0028]
An intermediate layer having an adhesive function is provided thereon. Examples of the material for the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are applied by dissolving in an appropriate solvent. The thickness of the intermediate layer is preferably 0.05 to 5 μm, more preferably 0.3 to 1 μm.
[0029]
A charge generation layer is formed on the intermediate layer. Examples of the charge generating material used in the present invention include selenium-tellurium, pyrylium, thiapyrylium dyes, phthalocyanine, anthantrone, dibenzapyrene quinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone and asymmetric quinocyanine pigments. And more preferably phthalocyanine pigments, such as oxytitanium phthalocyanine and hydroxyphthalocyanine. Among them, 9.0 °, 14.2 °, and 23.9 with a Bragg angle 2θ ± 0.2 ° in X-ray diffraction of CuKα. Oxytitanium phthalocyanine in crystalline form having strong peaks at 25 ° and 27.1 °, and 7.5 °, 9.9 °, 16.3 ° and 18.3 at Bragg angle 2θ ± 0.2 ° in X-ray diffraction of CuKα. A crystal form having strong peaks at 6 °, 25.1 ° and 28.3 °. If b carboxymethyl phthalocyanine is in contact with preferably these inorganic fine particles, it does not interfere with the dispersion stability.
[0030]
In the case of the function separation type, the charge generation layer is a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, a roll mill and a liquid containing the charge generation material together with a binder resin and a solvent in an amount of 0.3 to 4 times by mass. It is formed by dispersing well by a method such as a collision type high-speed disperser, applying a dispersion, and drying. The thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.1 to 2 μm.
[0031]
The charge transport layer is formed by applying a paint in which a binder resin and a charge transport material are dissolved in a solvent, and drying. The charge transport material is applied together with a binder resin in an amount of 0.5 to 2 times by mass and dried to form a charge transport layer. The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 10 to 30 μm.
[0032]
FIG. 3 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention.
[0033]
In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 2 at a predetermined peripheral speed in a direction indicated by an arrow. In the rotation process, the photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the primary charging means 3, and then the image from an exposure means (not shown) such as a slit exposure or a laser beam scanning exposure. Receives exposure light 4. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.
[0034]
The formed electrostatic latent image is then subjected to toner development by the developing unit 5, and the developed toner image is synchronized between the photosensitive member 1 and the transfer unit 6 between the photosensitive member 1 and the transfer unit 6 from a paper supply unit (not shown). The transfer material 6 is sequentially transferred to the transferred and transferred transfer material 7.
[0035]
The transfer material 7 that has undergone the image transfer is separated from the photoreceptor surface, introduced into the fixing means 8 and subjected to image fixing to be printed out of the apparatus as a copy.
[0036]
The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the untransferred toner by a cleaning unit 9, and further subjected to a charge removal process by a pre-exposure light 10 from a pre-exposure unit (not shown). Used for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.
[0037]
In the present invention, among the above-mentioned components such as the electrophotographic photosensitive member 1, the primary charging unit 3, the developing unit 5, and the cleaning unit 9, a plurality of components are integrally connected as a process cartridge. May be detachably attached to a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, a process in which at least one of the primary charging unit 3, the developing unit 5 and the cleaning unit 9 is integrally supported together with the photoreceptor 1 to form a cartridge, and which can be attached to and detached from the apparatus main body using guide means such as the rail 12 of the apparatus main body. The cartridge 11 can be used.
[0038]
When the electrophotographic apparatus is a copier or a printer, the image exposure light 4 is reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal, and a laser beam is emitted according to the signal. Light emitted by scanning, driving of an LED array, driving of a liquid crystal shutter array, and the like.
[0039]
The electrophotographic photoreceptor of the present invention can be widely used not only for electrophotographic copying machines but also for electrophotographic applications such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.
[0040]
Hereinafter, the present invention will be described in more detail with reference to Examples. In the examples, "parts" indicates parts by mass.
[0041]
【Example】
[Execution dispersion liquid 1]
20 parts of hydrophobized silica powder (trade name: KMPX-100, average particle size: 0.1 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed with 200 parts of monochlorobenzene, stirred, and dispersed by the apparatus shown in FIG. Processing was performed. The processing pressure during dispersion is 600 kgf / cm ² (60,000 kPa) was adjusted by the pump stroke. The liquid obtained from the discharge port was added again to obtain a dispersion liquid subjected to high-pressure treatment up to a total of 5 times (the high-pressure treatment was continued, but the particle size did not change after 5 times). Table 1 shows the results of the measurement of the dispersion average particle size and the particle size distribution of the hydrophobized silica powder with respect to the number of times of the high-pressure treatment using a product made by Leads and Northrup (trade name: Microtrac UPA particle size analyzer).
[0042]
[Comparative Dispersion 1]
Exactly the same treatment as in Example 1 was performed, except that the dispersion method was ultrasonic dispersion instead of the high-pressure treatment used in the dispersion liquid 1. The ultrasonic disperser had a 20 kHz oscillator, an oscillation output of 1 kW, and processing times of 30, 60, and 120 minutes, respectively. The particle size distribution of the dispersion obtained under each of these conditions was measured in the same manner as in Working dispersion 1. The results are shown in Table 1 (further ultrasonic dispersion was continued, but the particle size did not change after 120 minutes).
[0043]
[Execution dispersion liquid 2]
The particle size distribution was measured according to the measurement conditions of the working dispersion 1, except that the working dispersion 1 was kept standing for 2 weeks. The results are shown in Table 1 (however, only the particle size after 2 weeks for the high-pressure-treated product 5 times is shown).
[0044]
[Comparative dispersion liquid 2]
The particle size distribution was measured in accordance with the measurement conditions of the working dispersion 1, except that the dispersion of the comparative dispersion 1 was kept standing for 2 weeks. The results are shown in Table 1 (however, only the particle size after two weeks of the ultrasonic dispersion 120-minute product is shown).
[0045]
[Table 1]

[0046]
[Execution dispersion liquid 3]
20 parts of hydrophobic silica powder (trade name: KMPX-100, average particle size 0.1 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) and polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a thermoplastic resin ) 20 parts were mixed with 200 parts of monochlorobenzene, and dispersed, and the particle size distribution was measured in the same manner as in the dispersion 1, except that the mixture was stirred. (The high pressure treatment was continued, but the particle size did not change after 5 times.) T). Table 2 shows the results.
[0047]
[Comparative dispersion 3]
20 parts of hydrophobic silica powder (trade name: KMPX-100, average particle size 0.1 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) and polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a thermoplastic resin 20) Monochlorobenzene was mixed with 200 parts of monochlorobenzene and dispersed, and the particle size distribution was measured in the same manner as in Comparative Dispersion Liquid 1 except for stirring (further ultrasonic dispersion was continued, but the particle size changed after 120 minutes). Did not.) Table 2 shows the results.
[0048]
[Execution dispersion liquid 4]
The particle size distribution was measured according to the measurement conditions of the working dispersion 1, except that the working dispersion 3 was kept standing for 2 weeks. The results are shown in Table 2 (however, only the particle size after two weeks of the high-pressure treated product five times) is shown.
[0049]
[Comparative dispersion liquid 4]
The particle size distribution was measured in accordance with the measurement conditions for the working dispersion 1 except that the dispersion of the comparative dispersion 3 was left standing for 2 weeks. The results are shown in Table 2 (however, only the particle size after two weeks of the ultrasonic dispersion 120-minute product is shown).
[0050]
[Table 2]

[0051]
[Execution dispersion liquid 5]
The dispersion was measured in the same manner as in Working Dispersion 3, except that the thermoplastic resin was replaced with a polyarylate resin (weight average molecular weight: 100,000) represented by the following structural formula (1), and the particle size distribution was measured. . Table 3 shows the results. In addition, the average particle diameter of the working dispersion described in Table 3 is the particle diameter of a five-time product.
[0052]
Embedded image

[0053]
[Comparative dispersion liquid 5]
In Comparative Dispersion Liquid 3, the dispersion was the same except that the thermoplastic resin was replaced with the polyarylate resin (represented by the formula (1), and the particle size distribution was measured. The results are shown in Table 3. The results are shown in Table 3. The average particle size of the comparative dispersion is the particle size of the 120-minute product.
[0054]
[Execution dispersions 6 and 7]
The hydrophobized silica powder in the working dispersion 5 was converted to a hydrophobized silica powder (trade name: X-120, average particle size: 0.02 μm, manufactured by Shin-Etsu Chemical Co., Ltd.), silica doll (trade name: 30G-100, average) The results are shown in Table 3 except that the particle size was changed to 0.1 μm, manufactured by Nippon Chemical Industry Co., Ltd.).
[0055]
[Comparative dispersions 6, 7]
In Comparative Dispersion 5, the hydrophobized silica powder was converted to a hydrophobized silica powder (trade name: X-120, average particle size: 0.02 μm, manufactured by Shin-Etsu Chemical Co., Ltd.), silica doll (trade name: 30G-100, average) The results are shown in Table 3 except that the particle size was changed to 0.1 μm, manufactured by Nippon Chemical Industry Co., Ltd.).
[0056]
[Execution dispersions 8, 9]
The hydrophobized silica powder in the working dispersion 5 was prepared by using alumina (trade name: LS-235, average particle size: 0.1 μm, manufactured by Nippon Light Metal Co., Ltd.), zinc oxide (trade name: FINEX-25LP, average particle size: 0.1 μm). 1 μm, manufactured by Sakai Chemical Industry Co., Ltd.), and the results are shown in Table 3.
[0057]
[Comparative dispersions 8, 9]
In Comparative Dispersion 5, the hydrophobized silica powder was alumina (trade name: LS-235, average particle size: 0.1 μm, manufactured by Nippon Light Metal Co., Ltd.), zinc oxide (trade name: FINEX-25LP, average particle size: 0.1 μm) , Manufactured by Sakai Chemical Industry Co., Ltd.), and the results are shown in Table 3.
[0058]
[Execution dispersions 10 and 11]
The results are shown in Table 3 except that Hydrophobized silica powder (trade name: KMP-110, average particle size: 1.9 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) was used in the working dispersion liquid 5, and the results are shown in Table 3.
[0059]
[Comparative dispersion 10]
Table 3 shows the results except that the hydrophobized silica powder was replaced with the hydrophobized silica powder (trade name: KMP-110, average particle size: 1.9 μm, manufactured by Shin-Etsu Chemical Co., Ltd.) in Comparative Dispersion 5. Shown in
[0060]
[Execution dispersion liquid 11]
The results are shown in Table 3 except that the thermoplastic resin in the working dispersion 5 was replaced with the structural formula (2) (weight average molecular weight: 72,000) shown below.
[0061]
Embedded image

[0062]
[Comparative dispersion liquid 11]
The results are shown in Table 3 except that the thermoplastic resin in Comparative Dispersion 5 was replaced with the polycarbonate resin represented by the formula (2).
[0063]
[Execution dispersion liquid 12]
The results are shown in Table 3 except that the thermoplastic resin in the working dispersion 5 was replaced with the structural formula (3) shown below (weight average molecular weight: 69000).
[0064]
Embedded image

[0065]
[Comparative dispersion 12]
All of the comparative dispersion 5 was the same except that the thermoplastic resin was replaced with the resin represented by the formula (3) (the results are shown in Table 3).
[0066]
[Comparative dispersion 13]
The results are shown in Table 3 except that the hydrophobized silica powder in the working dispersion 5 was replaced with synthetic silica (trade name: Aerosil 300CF, average particle size 0.007 μm, manufactured by Tsuchiya Kaolin Industries, Ltd.).
[0067]
[Comparative dispersion 14]
The results are shown in Table 3 except that the hydrophobized silica powder in the working dispersion 5 was replaced with alumina (trade name: AL43M, average particle size: 2.2 μm, manufactured by Tsuchiya Kaolin Industries, Ltd.).
[0068]
[Table 3]

[0069]
The average particle size of the comparative dispersion is higher than the working dispersion. Also, the comparative dispersion has poor stability. Further, in the comparative dispersion liquid 13, a large amount of air bubbles were generated during the dispersion process, and the air bubbles caused a decrease in pressure, resulting in poor dispersion. After 3 hours from the dispersion, the gel became gel-like. It was also found that the comparative dispersion liquid 14 had the largest degree of sedimentation as compared with the other liquid dispersions.
[0070]
[Example 1]
An aluminum cylinder having a diameter of 30 mm and a length of 357.5 mm is used as a support, and a coating composed of the following materials is applied on the support by a dip coating method and thermally cured at 140 ° C. for 30 minutes to form a 15 μm conductive layer. Was formed.
[0071]
Conductive pigment: SnO ₂ Coated barium sulfate 10 parts
Pigment for resistance adjustment: 2 parts of titanium oxide
Binder resin: 6 parts of phenolic resin
Leveling material: 0.001 part of silicone oil
Solvent: methanol, methoxypropanol 0.2 / 0.8 20 parts
[0072]
Next, a solution obtained by dissolving 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon in a mixed solvent of 65 parts of methanol and 30 parts of n-butanol was applied thereon by dip coating, and then 100 ° C. for 10 minutes. After drying, an intermediate layer having a thickness of 0.5 μm was formed.
[0073]
Next, 4 parts of oxytitanium phthalocyanine (TiOPc) having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° at Bragg angles 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. And 2 parts of polyvinyl butyral (trade name: Esrec BM2, manufactured by Sekisui Chemical Co., Ltd.) and 60 parts of cyclohexanone were dispersed in a sand mill using glass beads of 1 mm in diameter for 4 hours. A dispersion was prepared. This was applied by a dip coating method and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.
[0074]
Next, 50 parts of a polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as a binder resin in 150 parts of the hydrophobized silica powder dispersion (high-pressure treated 5 times product) obtained in Working dispersion 1. 80 parts of monochlorobenzene and 40 parts of dichloromethane are added and dissolved, and a total of 40 parts of the charge transporting material represented by the following structural formula is added to the solution so that the mass ratio of the charge transporting material is (4) :( 5) = 8: 1.
Triarylamine compound represented by the following structural formula (4)
[0075]
Embedded image

A stilbene compound represented by the following structural formula (5)
[0076]
Embedded image

Was dissolved to form a coating for a charge transport layer, applied on the charge generation layer by a dip coating method, and dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 29 μm, thereby obtaining an electrophotographic photoreceptor. .
[0077]
[Comparative Example 1]
A photoconductor was prepared in exactly the same manner as in Example 1, except that the dispersion under the condition of 120 minutes was used as the dispersion of hydrophobic silica powder in Comparative dispersion 1.
[0078]
[Example 2]
A photoreceptor was produced in exactly the same manner as in Example 1, except that the charge transport layer coating obtained in Example 1 was left standing for 2 weeks.
[0079]
[Comparative Example 2]
A photoconductor was prepared in exactly the same manner as in Example 1 except that the charge transport layer coating obtained in Comparative Example 1 was used by standing for 2 weeks.
[0080]
[Comparative Example 3]
A photoconductor was prepared in exactly the same manner as in Example 1 except that the dispersion for liquid charge transport layer in Example 1 was replaced with 180 parts of monochlorobenzene and 80 parts of dichloromethane, except for the dispersion liquid 1.
[0081]
The photoconductors of Examples 1 and 2 and the photoconductors of Comparative Examples 1, 2, and 3 thus obtained were evaluated using a copying machine “GP-40” (manufactured by Canon Inc.). The evaluation method is shown below, and the evaluation results are shown in Table 4.
[0082]
The produced electrophotographic photoreceptor was transferred to "GP-40" (manufactured by Canon Inc.) having a process speed of 210 mm / sec by a copying machine having a roller contact charging means (AC / DC roller contact charging means) on which an AC voltage was superimposed. The measurement was performed under a normal temperature and normal humidity environment (N / N) at a temperature of 23 ° C. and a humidity of 50% RH. GP-40 was measured using a potential measuring jig having a probe attached to the developing position in order to measure the potential characteristics of the electrophotographic photosensitive member. The “potential” is a value obtained by measuring the charging potential Vd, the sensitivity EΔ500, and the residual potential Vr at the initial stage and after 40,000 sheets of continuous paper endurance. The larger the absolute value of the charging potential Vd, the better the charging ability, and the sensitivity EΔ500 is the amount of light required to attenuate the potential from −700 V to −200 V, and the smaller the value, the better the sensitivity.
[0083]
“Photoconductor defect” means an aggregate of hydrophobized silica powder by visual observation of the photoconductor surface.
[0084]
“Durable scraping” indicates the amount of photoreceptor scrap after 40,000 continuous paper passes. The film thickness was measured using an eddy current film thickness measuring device (Permascope type E111) manufactured by Fischer. The "durable image" shows the image quality after 40,000 sheets, and the image defects appearing on the halftone image were visually evaluated. As the types of image defects, image defects due to aggregates themselves, image defects due to scratches originating from aggregates in the circumferential direction of the photoreceptor, and the like may be observed.
[0085]
The image was an A4 grid pattern with a printing rate of 4%. The sequence was an intermittent mode in which the printing was stopped once for each print. When the toner ran out, it was replenished.
[0086]
[Table 4]

[0087]
[Examples 3 and 4]
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1, except that the amount of the hydrophobized silica powder dispersion (high-pressure treated 5 times) shown in Working dispersion 1 was changed to 70 parts and 110 parts, respectively. . Table 3 shows the compounding ratios of Examples 3 to 13. 5 and Table 6 show the results.
[0088]
[Example 5]
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the charge transport layer binder resin was changed to the polyarylate resin represented by the formula (1).
[0089]
[Example 6]
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the amount of the hydrophobized silica powder dispersion (high-pressure treated 5 times) shown in Working dispersion 3 was changed to 160 parts, and the amount of the polycarbonate resin was changed to 35 parts. Created and evaluated.
[0090]
[Example 7]
The amount of the hydrophobized silica powder dispersion (five times of high pressure treatment) shown in Working dispersion 5 was 160 parts, and the charge transport binder was changed to the polyarylate resin represented by the formula (1), and the resin amount was 35 parts. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except that the composition was changed to.
[0091]
[Examples 8 to 11]
As the charge transport layer, the dispersions obtained in Working Dispersions 6, 8, 9, and 10 (five times of high pressure treatment) and the compounding ratio, and the binder for the charge transport layer were used as shown in Table 5, except that An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1.
[0092]
[Example 12]
The amount of the hydrophobized silica powder dispersion (five times of high pressure treatment) shown in Working dispersion 11 was 160 parts, and the amount of resin was 35 parts instead of the binder represented by the structural formula (3) as the charge transport binder. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in Example 1 except for changing.
[0093]
Example 13
The charge transport layer was changed in the electrophotographic photoreceptor of Example 1, and a protective layer was further provided. That is, 50 parts of a polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 40 parts of the charge transport material shown in Example 1 were added together with 200 parts of monochlorobenzene and 80 parts of dichloromethane as a charge transport layer, and dissolved. Then, a charge transport layer paint was applied, applied by a dip coating method, and dried at 120 ° C. for 60 minutes to provide a charge transport layer having a film thickness of 21 μm.
[0094]
Next, as a protective layer, 25 parts of the hydrophobized silica powder dispersion obtained in Working Dispersion 1 (high-pressure treated 5 times product), 4 parts of the charge transport material represented by the formula (4) used in the charge transport layer, and polycarbonate A resin (trade name: Iupilon Z800, manufactured by Mitsubishi Gas Chemical Co., Ltd.) (4 parts), monochlorobenzene (200 parts), and dichloromethane (250 parts) were mixed and dissolved to prepare a coating for a surface protective layer. This paint was applied on the charge transport layer by atomization and dried at 120 ° C. for 60 minutes to form a protective layer having a thickness of 5.0 μm, and an electrophotographic photosensitive member was prepared and evaluated.
[0095]
[Comparative Examples 4 to 8]
As the charge transport layer, the dispersions (120-minute products) obtained in Comparative Dispersions 5, 6, 8, 9, and 13 and the blending ratio and the binder for the charge transport layer were used as shown in Table 5, respectively. An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1. Table 6 shows the results.
[0096]
[Comparative Example 9]
In Example 13, the protective layer was changed as follows.
[0097]
That is, it was prepared and evaluated in the same manner as in Example 13 except that Comparative Dispersion Liquid 1 was used as the protective layer.
[0098]
[Table 5]

[0099]
[Table 6]

[0100]
In the examples, the photoreceptor had no aggregates, and the surface was smooth and uniform. Further, it showed good electrophotographic characteristics and also had good image quality.
[0101]
[Example 14]
In Example 1, an electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the support was replaced with an aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm, and the measurement was performed using the following evaluator. This is similar to the first embodiment.
[0102]
・ Evaluation machine
LBP-SX (laser beam printer) (manufactured by Canon Inc.)
Charging method: Corona charging
Process speed: 47mm / sec
Cleaning blade: Set linear pressure to photoreceptor to 1.4 times normal
Dark section potential Vd: -500
Laser light amount: set to a light amount at which the bright portion potential Vl becomes -100 V when irradiated with a laser beam having a wavelength of 802 nm.
The electrophotographic characteristics were measured using a potential measuring jig having a probe attached to the developing position.
[0103]
In addition, the number of durable sheets was 5,000.
[0104]
The results are shown in Table 7 below.
[0105]
[Example 15]
The electrophotographic photoreceptor in Example 1 was evaluated in the same manner as in Example 1 except that the measurement was performed using the following evaluator.
[0106]
・ Evaluation machine
NP-6030 (plain paper copier) (manufactured by Canon Inc.)
Charging method: DC voltage application (DC charging)
Process speed: 200 (mm / sec)
Cleaning blade: Set linear pressure to photoreceptor to 1.4 times normal
Dark part potential Vd: -400
Laser light intensity: set to the light intensity at which the bright part potential Vl becomes -70V
The electrophotographic characteristics were measured using a potential measuring jig having a probe attached to the developing position.
[0107]
The number of endurance sheets was 40,000.
[0108]
The results are shown in Table 7 below.
[0109]
[Comparative Example 10]
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that the support was replaced with an aluminum cylinder having a diameter of 30 mm and a length of 260.5 mm, and the measurement was conducted in the same manner as in Example 14.
[0110]
[Comparative Example 11]
The measurement was performed in the same manner as in Example 15 for the electrophotographic photosensitive member of Comparative Example 1.
[0111]
[Table 7]

[0112]
The embodiments of the present invention have been described above. Preferred embodiments of the present invention are listed below.
[0113]
[Embodiment 1]
In an electrophotographic photosensitive member containing a surface layer containing inorganic fine particles having a volume average particle diameter of 0.01 to 2.0 μm, the inorganic fine particles used for the surface layer are pressurized to a high pressure state together with a solvent, and An electrophotographic photoreceptor characterized by being pulverized and dispersed.
[0114]
[Embodiment 2]
2. The electrophotographic photoreceptor according to claim 1, wherein the pressurization, pulverization, and dispersion are performed by pressure-feeding the inorganic fine particles and the solvent to a fine flow path and performing high-pressure liquid collision in the fine flow path.
[0115]
[Embodiment 3]
2. The electrophotographic photoreceptor according to claim 1, wherein the pressurization, pulverization, and dispersion are performed by pressure-feeding the inorganic fine particles and the solvent to a fine channel, and liquid collision with an obstacle wall immediately after an outlet of the channel.
[0116]
[Embodiment 4]
In an electrophotographic photosensitive member containing a surface layer containing inorganic fine particles having a volume average particle diameter of 0.01 to 2.0 μm, the inorganic fine particles used in the surface layer are pressurized to a high pressure state together with a thermoplastic resin and a solvent. An electrophotographic photoreceptor characterized in that it is pulverized and dispersed by liquid collision.
[0117]
[Embodiment 5]
The electrophotographic photoreceptor according to embodiment 4, wherein the pressurization, pulverization, and dispersion are performed by pressure-feeding the inorganic fine particles, the thermoplastic resin, and the solvent to a fine flow path, and performing high-pressure liquid collision in the fine flow path. .
[0118]
[Embodiment 6]
The electron according to embodiment 4, wherein the pressurization, pulverization, and dispersion are performed by pressure-feeding the inorganic fine particles, the thermoplastic resin, and the solvent to a fine channel, and liquid collision with an obstacle wall immediately after a discharge port of the channel. Photoreceptor.
[0119]
[Embodiment 7]
The electrophotographic photosensitive member according to any one of embodiments 1 to 6, wherein the surface layer of the photosensitive member is a charge transport layer.
[0120]
[Embodiment 8]
The electrophotographic photoreceptor according to any one of embodiments 4 to 7, wherein the thermoplastic resin is a polycarbonate resin or a polyarylate resin.
[0121]
[Embodiment 9]
The electrophotographic photoreceptor according to any one of embodiments 1 to 8, wherein the inorganic fine particles are silica fine particles.
[0122]
[Embodiment 10]
The electrophotographic photosensitive member according to any one of embodiments 1 to 9, wherein the inorganic fine particles are hydrophobic silica fine particles.
[0123]
[Embodiment 11]
The electrophotographic photosensitive member according to any one of Embodiments 1 to 10, which is used in a contact charging system.
[0124]
【The invention's effect】
According to the present invention, a surface layer coating material which is pressurized to a high pressure state, and can be dispersed in a fine particle by inorganic particles by pulverization and dispersion by high-pressure liquid collision, and which can maintain liquid stability for a long time, is obtained. The surface of the electrophotographic photoreceptor using the surface layer paint forms a uniform surface without agglomerates, has good electrical sensitivity, and has excellent charging characteristics, sensitivity, and repetitive potential stability of residual potential. It is possible to obtain an electrophotographic photosensitive member having excellent scratch resistance, abrasion resistance and abrasion resistance, and to provide an excellent image having no image quality image defects.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a liquid collision type high-speed disperser used in the present invention.
FIG. 2 is an external view of a liquid collision jig in a liquid collision type high-speed dispersion machine used in the present invention.
FIG. 3 is a view showing a schematic configuration of an electrophotographic apparatus having a process cartridge having an electrophotographic photosensitive member according to the present invention.

Claims (4)

In an electrophotographic photosensitive member containing a surface layer containing inorganic fine particles having a volume average particle diameter of 0.01 to 2.0 μm, the inorganic fine particles used for the surface layer are pressurized to a high pressure state together with a solvent, and An electrophotographic photoreceptor characterized by being pulverized and dispersed. In an electrophotographic photosensitive member containing a surface layer containing inorganic fine particles having a volume average particle diameter of 0.01 to 2.0 μm, the inorganic fine particles used in the surface layer are pressurized to a high pressure state together with a thermoplastic resin and a solvent. An electrophotographic photoreceptor characterized in that it is pulverized and dispersed by liquid collision. 3. An electrophotographic photoreceptor according to claim 1, wherein at least one means selected from the group consisting of a charging means, a developing means and a cleaning means is integrally supported, and is detachably mountable to an electrophotographic apparatus main body. Process cartridge. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposing unit, a developing unit, and a transferring unit.

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