JP2005017381A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can enough suppress irregular density in stripes and realize both of improvement in picture quality and a higher speed of image formation even when a surface light emitting laser which increases the number of laser beams is used. <P>SOLUTION: The apparatus is equipped with an electrophotographic photoreceptor 12 having a conductive substrate and a photosensitive layer, an electrifying apparatus 14, an exposure apparatus 16, a developing apparatus 18 and a transfer apparatus 32. The exposure apparatus 16 has a configuration employing a multi-beam system. The photosensitive layer has a first metal phthalocyanine-containing layer containing a metal phthalocyanine and showing ≥0.5 absorbance A<SB>1</SB>expressed by formula (1): A<SB>1</SB>=log<SB>10</SB>(T<SB>0</SB>/T), wherein T<SB>0</SB>and T represent the quantities of incident light and transmitted light, respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

［一般式（ＩＩ） 中、Ａｒ^３〜Ａｒ^６は、それぞれ独立に置換あるいは未置換のアリール基を表し、Ａｒ^７は置換若しくは未置換のアリール基又はアリーレン基を表し、ｋは０又は１を表し、Ａｒ^３〜Ａｒ^７のうちｂ個は−Ｄ−ＳｉＲ^１ _３−ａ（ＯＲ^２）_ａで表される基に結合する結合手を有する。］
【０１３５】
上記一般式（ＩＩ）中のＡｒ^３〜Ａｒ^６としては、下記式（ＩＩ−１）〜（Ｉ−７）のうちのいずれかであることが好ましい。
【０１３６】
【化２】

【０１３７】
【化３】

【０１３８】
【化４】

【０１３９】
【化５】

【０１４０】
【化６】

【０１４１】
【化７】

−Ａｒ−Ｚ’_ｓ−Ａｒ−Ｘ_ｍ （ＩＩ−７）
【０１４２】
［式中、Ｒ^３は水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルキル基若しくは炭素数１〜４のアルコキシ基で置換されたフェニル基、又は未置換のフェニル基、炭素数７〜１０のアラルキル基からなる群より選ばれる１種を表し、Ｒ^４〜Ｒ^６はそれぞれ水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルキル基若しくは炭素数１〜４のアルコキシ基で置換されたフェニル基、又は未置換のフェニル基、炭素数７〜１０のアラルキル基、ハロゲン原子からなる群より選ばれる１種を表し、Ａｒは置換又は未置換のアリーレン基を表し、Ｘは一般式（Ｉ）中の−Ｄ−ＳｉＲ^１ _３−ａ（ＯＲ^２）_ａを表し、ｍ及びｓは０又は１を表し、ｔは１〜３の整数を表す。］
【０１４３】
ここで、式（ＩＩ−７）中のＡｒとしては、下記式（ＩＩ−８）又は（ＩＩ−９）で表されるものが好ましい。
【０１４４】
【化８】

【０１４５】
【化９】

【０１４６】
［式中、Ｒ^７及びＲ^８はそれぞれ水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基若しくは炭素数１〜４のアルコキシ基で置換されたフェニル基又は未置換のフェニル基、炭素数７〜１０のアラルキル基、ハロゲン原子からなる群より選ばれる１種を表し、ｔは１〜３の整数を表す。］
【０１４７】
また、式（ＩＩ−７）中のＺ’としては、下記式（ＩＩ−１０）〜（ＩＩ−１７）のうちのいずれかで表されるものが好ましい。
−（ＣＨ_２）_ｑ− （ＩＩ−１０）
−（ＣＨ_２ＣＨ_２Ｏ）_ｒ− （ＩＩ−１１）
【０１４８】
【化１０】

【０１４９】
【化１１】

【０１５０】
【化１２】

【０１５１】
【化１３】

【０１５２】
【化１４】

【０１５３】
【化１５】

【０１５４】
［式中、Ｒ^９及びＲ^１０はそれぞれ水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアルコキシ基若しくは炭素数１〜４のアルコキシ基で置換されたフェニル基又は未置換のフェニル基、炭素数７〜１０のアラルキル基、ハロゲン原子からなる群より選ばれる１種を表し、Ｗは２価の基を表し、ｑ及びｒはそれぞれ１〜１０の整数を表し、ｔはそれぞれ１〜３の整数を表す。］
【０１５５】
上記式（ＩＩ−１６）、（ＩＩ−１７）中のＷとしては、下記（ＩＩ−１８）〜（ＩＩ−２６）で表される２価の基のうちのいずれかであることが好ましい。−ＣＨ_２− （ＩＩ−１８）
−Ｃ（ＣＨ_３）_２− （ＩＩ−１９）
−Ｏ− （ＩＩ−２０）
−Ｓ− （ＩＩ−２１）
−Ｃ（ＣＦ_３）_２− （ＩＩ−２２）
−Ｓｉ（ＣＨ_３）_２− （ＩＩ−２３）
【０１５６】
【化１６】

【０１５７】
【化１７】

【０１５８】
【化１８】

［式中、ｕは０〜３の整数を表す］
【０１５９】
また、一般式（ＩＩ）中、Ａｒ^５は、ｋが０のときはＡｒ^１〜Ａｒ^４の説明で例示されたアリール基であり、ｋが１のときはかかるアリール基から所定の水素原子を除いたアリーレン基である。一般式（ＩＩ）で表される化合物の具体例としては、例えば、特開２００１−８３７２８号公報における表１〜表５５に記載の化合物番号１〜２７４のものが使用できる。
【０１６０】
一般式（Ｉ）で表される化合物は、１種を単独で用いてもよく、また、２種以上を組み合わせて用いてもよい。
【０１６１】
また、一般式（Ｉ）で表される化合物と共に、硬化膜の機械的強度をさらに向上させる目的で、一般式（Ｉ）で表される化合物と結合可能な基を有する化合物を併用してもよい。一般式（Ｉ）で表される化合物と結合可能な基とは、一般式（Ｉ）で表される化合物を加水分解した際に生じるシラノール基と結合可能な基を意味する。具体的には、−ＳｉＲ^１ _３−ａ（ＯＲ^２）_ａで表される基、エポキシ基、イソシアネート基、カルボキシル基、ヒドロキシ基、ハロゲン原子等が挙げられる。これらのうち、−ＳｉＲ^１ _３−ａ（ＯＲ^２）_ａで表される基、エポキシ基、イソシアネート基を有する場合、一般式（Ｉ）で表される化合物はより強い機械的強度を有するため好ましい。さらに、これらの基を分子内に２つ以上持つものは、硬化膜の架橋構造が３次元的になり、より強い機械的強度を有するため好ましい。
【０１６２】
これらの内、最も好ましい化合物として一般式（ＩＩＩ）で示される化合物が挙げられる。
Ｂ−Ａ_ｎ （ＩＩＩ）
［一般式（ＩＩＩ）中、Ａは−ＳｉＲ^１ _３−ａ（ＯＲ^２）_ａで表される基であり、Ｒ^１、Ｒ^２、ａは一般式（Ｉ）中のＲ^１、Ｒ^２、ａと同一の定義内容を表す。Ｂは、ｎ価の炭化水素基及び−ＮＨ−から選択される少なくとも１種から構成されるｎ価の基を表し、ｎは２以上の整数を表す。］
【０１６３】
一般式（ＩＩＩ）において、Ｂがｎ価の炭化水素基である場合又は当該炭化水素基を含んで構成される場合、当該炭化水素基は、アルキル基、アリール基、アルキルアリール基、アリールアルキル基のいずれであってもよい。また、当該炭化水素基が有するアルキル基は直鎖状、分岐鎖状のいずれであってもよい。さらに、当該炭化水素基は置換基を有していてもよい。
【０１６４】
一般式（ＩＩＩ）で表される化合物は、−ＳｉＲ^１ _３−ａ（ＯＲ^２）_ａで表される加水分解性基を有する置換ケイ素基を有している化合物である。一般式（ＩＩＩ）で表される化合物は、一般式（Ｉ）で表される化合物との反応又は一般式（ＩＩＩ）で表される化合物同士の反応により、Ｓｉ−Ｏ−Ｓｉ結合を形成して３次元的な架橋硬化膜を与える。一般式（ＩＩＩ）で表される化合物と一般式（Ｉ）で表される化合物とを併用すると、硬化膜の架橋構造が３次元的になり易く、また、硬化膜に適度な可とう性が付与されるため、より強い機械的強度が得られる。一般式（ＩＩＩ）で表される化合物としては、下記式（ＩＩＩ−１）〜（ＩＩＩ−５）で表される化合物が好ましい。
【０１６５】
【化１９】

【０１６６】
【化２０】

【０１６７】
【化２１】

【０１６８】
【化２２】

【０１６９】
【化２３】

［式中、Ｔ^１，Ｔ^２はそれぞれ独立に枝分かれしていてもよい２価又は３価の炭化水素基、Ａは先に述べた加水分解性を有する置換ケイ素基を表す。ｈ，ｉ，ｊはそれぞれ独立に１〜３の整数であるが分子内のＡの数が２以上となるように選ばれる。］
【０１７０】
下記式（ＩＩＩ−１）〜（ＩＩＩ−５）で表される化合物の具体例を表１に示す。
【０１７１】
【表１】

【０１７２】
一般式（Ｉ）で示される化合物は単独で使用しても良いし、膜の成膜性、可とう性を調整する等の目的から、一般式（ＩＩＩ）で示される化合物や、他のカップリング剤、フッ素化合物と混合して用いても良い。このような化合物として、各種シランカップリング剤、および市販のシリコーン系ハードコート剤を用いることができる。
【０１７３】
シランカップリング剤としては、ビニルトリクロロシラン、ビニルトリメトキシシラン、ビニルトリエトキシシラン、γ−グリシドキシプロピルメチルジエトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、γ−アミノプロピルトリメトキシシラン、γ−アミノプロピルメチルジメトキシシラン、Ｎ−β（アミノエチル）γ−アミノプロピルトリエトキシシラン、テトラメトキシシラン、メチルトリメトキシシラン、ジメチルジメトキシシラン、等を用いることができる。市販のハードコート剤としては、ＫＰ−８５、Ｘ−４０−９７４０、Ｘ−４０−２２３９（以上、信越シリコーン社製）、およびＡＹ４２−４４０、ＡＹ４２−４４１、ＡＹ４９−２０８（以上、東レダウコーニング社製）、等を用いることができる。また、撥水製等の付与のために、（トリデカフルオロ−１，１，２，２−テトラヒドロオクチル）トリエトキシシラン、（３，３，３−トリフルオロプロピル）トリメトキシシラン、３−（ヘプタフルオロイソプロポキシ）プロピルトリエトキシシラン、１Ｈ，１Ｈ，２Ｈ，２Ｈ−パーフルオロアルキルトリエトキシシラン、１Ｈ，１Ｈ，２Ｈ，２Ｈ−パーフルオロデシルトリエトキシシラン、１Ｈ，１Ｈ，２Ｈ，２Ｈ−パーフルオロオクチルトリエトシキシラン、等の含フッ素化合物を加えても良い。シランカップリング剤は任意の量で使用できるが、含フッ素化合物の量は、フッ素を含まない化合物に対して重量で０．２５以下とすることが望ましい。これを越えると、架橋膜の成膜性に問題が生じる場合がある。
【０１７４】
これらのコーティング液の調整は、無溶媒で行うか、必要に応じてメタノール、エタノール、プロパノール、ブタノール等のアルコール類；アセトン、メチルエチルケトン等のケトン類；テトラヒドロフラン、ジエチルエーテル、ジオキサン等のエーテル類等が使用できるが、好ましくは沸点が１００℃以下のものであり、任意に混合しての使用もできる。また、溶剤量は任意に設定できるが、少なすぎると一般式（Ｉ）で示される化合物が析出しやすくなるため、一般式（Ｉ）で示される化合物１部に対し、好ましくは０．５〜３０重量部、より好ましくは１〜２０重量部の割合で使用される。反応温度および時間は原料の種類によっても異なるが、通常、０〜１００℃、好ましくは１０〜７０℃、特に好ましくは１５０〜５０℃で行うことが好ましい。反応時間に特に制限はないが、反応時間が長くなるとゲル化を生じ易くなるため、１０分から１００時間の範囲で行うことが好ましい。
【０１７５】
コーティング液調整のために、系に不溶な固体触媒として以下のような触媒を用い、あらかじめ加水分解することができる。
陽イオン交換樹脂：アンバーライト１５、アンバーライト２００Ｃ、アンバーリスト１５（以上、ローム・アンド・ハース社製）；ダウエックスＭＷＣ−１−Ｈ、ダウエックス８８、ダウエックスＨＣＲ−Ｗ２（以上、ダウ・ケミカル社製）；レバチットＳＰＣ−１０８、レバチットＳＰＣ−１１８（以上、バイエル社製）；ダイヤイオンＲＣＰ−１５０Ｈ（三菱化成社製）；スミカイオンＫＣ−４７０、デュオライトＣ２６−Ｃ、デュオライトＣ−４３３、デュオライト−４６４（以上、住友化学工業社製）；ナフィオン−Ｈ（デュポン社製）等。
陰イオン交換樹脂：アンバーライトＩＲＡ−４００、アンバーライトＩＲＡ−４５（以上、ローム・アンド・ハース社製）等。
プロトン酸基を含有する基が表面に結合されている無機固体：Ｚｒ（Ｏ_３ＰＣＨ_２ＣＨ_２ＳＯ_３Ｈ）_２，Ｔｈ（Ｏ_３ＰＣＨ_２ＣＨ_２ＣＯＯＨ）_２等。
プロトン酸基を含有するポリオルガノシロキサン：スルホン酸基を有するポリオルガノシロキサン等。
【０１７６】
ヘテロポリ酸：コバルトタングステン酸、リンモリブデン酸等。
イソポリ酸：ニオブ酸、タンタル酸、モリブデン酸等。
単元系金属酸化物：シリカゲル、アルミナ、クロミア、ジルコニア、ＣａＯ、ＭｇＯ等。
複合系金属酸化物：シリカ−アルミナ、シリカ−マグネシア、シリカ−ジルコニア、ゼオライト類等。
粘土鉱物：酸性白土、活性白土、モンモリロナイト、カオリナイト等。
金属硫酸塩：ＬｉＳＯ_４，ＭｇＳＯ_４等。
金属リン酸塩：リン酸ジルコニア、リン酸ランタン等。
金属硝酸塩：ＬｉＮＯ_３，Ｍｎ（ＮＯ_３）_２等。
アミノ基を含有する基が表面に結合されている無機固体：シリカゲル上にアミノプロピルトリエトキシシランを反応させて得られた固体等。
アミノ基を含有するポリオルガノシロキサン：アミノ変性シリコーン樹脂等。
【０１７７】
これらの触媒のうち、少なくとも１種を用いて加水分解縮合反応を行わせる。これらの触媒は、固定床中に設置し反応を流通式に行うこともできるし、バッチ式に行うこともできる。触媒の使用量は、特に限定されないが、加水分解性ケイ素置換基を含有する材料の合計量に対して０．１〜２０ｗｔ％が好ましい。
【０１７８】
加水分解縮合させる際の水の添加量は特に限定されないが、生成物の保存安定性やさらに重合に供する際のゲル化抑制に影響するため、好ましくは一般式（Ｉ）で示される化合物の加水分解性基をすべて加水分解するのに必要な理論量に対して、好ましくは３０〜５００％、さらに好ましくは５０〜３００％の範囲の割合で使用することが好ましい。水の量が５００％よりも多い場合、生成物の保存安定性が悪くなったり、生成物が析出しやすくなったりする傾向がある。一方、水の量が３０％より少ない場合、未反応の化合物が増大してコーティング液を塗布、硬化時に相分離を起こしたり、強度低下を起こしたりする傾向がある。
【０１７９】
さらに、硬化触媒としては、以下の様なものを挙げることができる。塩酸、酢酸、リン酸、硫酸等のプロトン酸、アンモニア、トリエチルアミン等の塩基、ジブチル錫ジアセテート、ジブチル錫ジオクトエート、オクエ酸第一錫等の有機錫化合物、テトラ−ｎ−ブチルチタネート、テトライソプロピルチタネート等の有機チタン化合物、アルミニウムトリブトキシド、アルミニウムトリアセチルアセトナート等の有機アルミニウム化合物、有機カルボン酸の鉄塩、マンガン塩、コバルト塩、亜鉛塩、ジルコニウム塩等が挙げられる。中でも、保存安定性の点で金属化合物が好ましく、さらに、金属のアセチルアセトナート、あるいは、アセチルアセテートが好ましく、特にアルミニウムトリアセチルアセトナートが好ましい。
【０１８０】
硬化触媒の使用量は任意に設定できるが、保存安定性、特性、強度等の点で加水分解性ケイ素置換基を含有する材料の合計量に対して０．１〜２０ｗｔ％が好ましく、０．３〜１０ｗｔ％がより好ましい。硬化温度は、任意に設定できるが、所望の強度を得るためには６０℃以上、より好ましくは８０℃以上に設定される。硬化時間は、必要に応じて任意に設定できるが、１０分〜５時間が好ましい。また、硬化反応を行ったのち、高湿度状態に保ち、特性の安定化を図ることも有効である。さらに、用途によっては、ヘキサメチルジシラザンや、トリメチルクロロシラン等を用いて表面処理を行い、疎水化することもできる。
【０１８１】
電子写真感光体の表面架橋硬化膜には、帯電器で発生するオゾン等の酸化性ガスによる劣化を防止する目的で、酸化防止剤を添加することが好ましい。感光体表面の機械的強度を高め、感光体が長寿命になると、感光体が酸化性ガスに長い時間接触することになるため、従来のものより強い酸化耐性が要求される。酸化防止剤としては、ヒンダードフェノール系またはヒンダードアミン系が望ましく、有機イオウ系酸化防止剤、フォスファイト系酸化防止剤、ジチオカルバミン酸塩系酸化防止剤、チオウレア系酸化防止剤、ベンズイミダゾール系酸化防止剤、等の公知の酸化防止剤を用いてもよい。酸化防止剤の添加量としては２０重量％以下が望ましく、１０重量％以下がさらに望ましい。
【０１８２】
ヒンダードフェノール系酸化防止剤としては、２，６−ジ−ｔ−ブチル−４−メチルフェノール、２，５−ジ−ｔ−ブチルヒドロキノン、Ｎ，Ｎ’−ヘキサメチレンビス（３，５−ジ−ｔ−ブチル−４−ヒドロキシヒドロシンナマイド）、３，５−ジ−ｔ−ブチル−４−ヒドロキシ−ベンジルフォスフォネート−ジエチルエステル、２，４−ビス［（オクチルチオ）メチル］−ｏ−クレゾール、２，６−ジ−ｔ−ブチル−４−エチルフェノール、２，２’−メチレンビス（４−メチル−６−ｔ−ブチルフェノール）、２，２’−メチレンビス（４−エチル−６−ｔ−ブチルフェノール）、４，４’−ブチリデンビス（３−メチル−６−ｔ−ブチルフェノール）、２，５−ジ−ｔ−アミルヒドロキノン、２−ｔ−ブチル−６−（３−ブチル−２−ヒドロキシ−５−メチルベンジル）−４−メチルフェニルアクリレート、４，４’−ブチリデンビス（３−メチル−６−ｔ−ブチルフェノール）、等が挙げられる。
【０１８３】
また、放電ガス耐性、機械的強度、耐傷性、粒子分散性、粘度コントロール、トルク低減、磨耗量コントロール、ポットライフの延長等の目的でアルコールに溶解する樹脂を加えることもできる。アルコール系溶剤に可溶な樹脂としては、ポリビニルブチラール樹脂、ポリビニルホルマール樹脂、ブチラールの一部がホルマールやアセトアセタール等で変性された部分アセタール化ポリビニルアセタール樹脂等のポリビニルアセタール樹脂（例えば、積水化学社製エスレックＢ、Ｋ等）、ポリアミド樹脂、セルロ−ス樹脂、フェノール樹脂等が挙げられる。特に、電気特性上ポリビニルアセタール樹脂が好ましい。上記樹脂の分子量は２０００〜１０００００が好ましく、５０００〜５００００がさらに好ましい。分子量が２０００未満の場合は所望の効果が得られなくなる傾向があり、１０００００を超えると溶解度が低くなり添加量が限られてしまったり、塗布時に製膜不良の原因になったりする傾向がある。樹脂の添加量は１〜４０重量％が好ましく、さらに好ましくは１〜３０重量％であり、５〜２０重量％が最も好ましい。１重量％未満の場合は所望の効果が得られにくくなる傾向にあり、他方、４０重量％を超えると高温高湿下での画像ボケが発生しやすくなる傾向にある。
【０１８４】
更に、電子写真感光体表面の耐汚染物付着性、潤滑性を改善するために、各種微粒子を添加することもできる。それらは、単独で用いることもできるが、２種以上を併用してもよい。微粒子の一例として、ケイ素含有微粒子を挙げることができる。ケイ素含有微粒子とは、構成元素にケイ素を含む微粒子であり、具体的には、コロイダルシリカおよびシリコーン微粒子等が挙げられる。ケイ素含有微粒子として用いられるコロイダルシリカは、平均粒子径１〜１００ｎｍ、好ましくは１０〜３０ｎｍの酸性もしくはアルカリ性の水分散液、又はアルコール、ケトン、エステル等の有機溶媒中に分散させたものから選ばれ、一般に市販されているものを使用することができる。最表面層中のコロイダルシリカの固形分含有量は、特に限定されるものではないが、製膜性、電気特性、強度の面から最表面層の全固形分を基準として、０．１〜５０重量％の範囲、より好ましくは０．１〜３０重量％の範囲で用いられる。
【０１８５】
ケイ素含有微粒子として用いられるシリコーン微粒子は、球状で、平均粒子径１〜５００ｎｍ、好ましくは１０〜１００ｎｍのシリコーン樹脂粒子、シリコーンゴム粒子、シリコーン表面処理シリカ粒子から選ばれ、一般に市販されているものを使用することができる。シリコーン微粒子は、化学的に不活性で、樹脂への分散性に優れる小径粒子であり、さらに十分な特性を得るために必要とされる含有量が低いため、架橋反応を阻害することなく、電子写真感光体の表面性状を改善することができる。即ち、強固な架橋構造中に均一に取り込まれた状態で、電子写真感光体表面の潤滑性、撥水性を向上させ、長期間にわたって良好な耐摩耗性、耐汚染物付着性を維持することができる。電子写真感光体における最表面層中のシリコーン微粒子の含有量は、最表面層の全固形分を基準として、０．１〜３０重量％の範囲であり、好ましくは０．５〜１０重量％の範囲である。
【０１８６】
また、その他の微粒子としては、４弗化エチレン、３弗化エチレン、６弗化プロピレン、弗化ビニル、弗化ビニリデン等のフッ素系微粒子や”第８回ポリマー材料フォーラム講演予稿集ｐ８９”に示される様な、フッ素樹脂と水酸基を有するモノマーを共重合させた樹脂からなる微粒子、ＺｎＯ−Ａｌ_２Ｏ_３、ＳｎＯ_２−Ｓｂ_２Ｏ_３、Ｉｎ_２Ｏ_３−ＳｎＯ_２、ＺｎＯ−ＴｉＯ_２、ＺｎＯ−ＴｉＯ_２、ＭｇＯ−Ａｌ_２Ｏ_３、ＦｅＯ−ＴｉＯ_２、ＴｉＯ_２、ＳｎＯ_２、Ｉｎ_２Ｏ_３、ＺｎＯ、ＭｇＯ等の半導電性金属酸化物を挙げることができる。
【０１８７】
また、同様の目的でシリコーンオイル等のオイルを添加することもできる。シリコーンオイルとしては、ジメチルポリシロキサン、ジフェニルポリシロキサン、フェニルメチルシロキサン等のシリコーンオイル、アミノ変性ポリシロキサン、エポキシ変性ポリシロキサン、カルボキシル変性ポリシロキサン、カルビノール変性ポリシロキサン、メタクリル変性ポリシロキサン、メルカプト変性ポリシロキサン、フェノール変性ポリシロキサン等の反応性シリコーンオイル、ヘキサメチルシクロトリシロキサン、オクタメチルシクロテトラシロキサン、デカメチルシクロペンタシロキサン、ドデカメチルシクロヘキサシロキサン等の環状ジメチルシクロシロキサン類、１，３，５−トリメチル−１，３，５−トリフェニルシクロトリシロキサン、１，３，５，７−テトラメチル−１，３，５，７−テトラフェニルシクロテトラシロキサン、１，３，５，７，９−ペンタメチル−１，３，５，７，９−ペンタフェニルシクロペンタシロキサン等の環状メチルフェニルシクロシロキサン類、ヘキサフェニルシクロトリシロキサン等の環状フェニルシクロシロキサン類、３−（３，３，３−トリフルオロプロピル）メチルシクロトリシロキサン等のフッ素含有シクロシロキサン類、メチルヒドロシロキサン混合物、ペンタメチルシクロペンタシロキサン、フェニルヒドロシクロシロキサン等のヒドロシリル基含有シクロシロキサン類、ペンタビニルペンタメチルシクロペンタシロキサン等のビニル基含有シクロシロキサン類等の環状のシロキサン等を挙げることができる。
【０１８８】
また、可塑剤、表面改質剤、酸化防止剤、光劣化防止剤等の添加剤を使用することもできる。可塑剤としては、ビフェニル、塩化ビフェニル、ターフェニル、ジブチルフタレート、ジエチレングリコールフタレート、ジオクチルフタレート、トリフェニル燐酸、メチルナフタレン、ベンゾフェノン、塩素化パラフィン、ポリプロピレン、ポリスチレン、各種フルオロ炭化水素等が挙げられる。
【０１８９】
電荷輸送性を有し、架橋構造を有するシロキサン系樹脂は、優れた機械的強度を有する上に光電特性も十分であるため、これをそのまま積層型感光体の電荷輸送層として用いることもできる。その場合、ブレードコーティング法、マイヤーバーコーティング法、スプレーコーティング法、浸漬コーティング法、ビードコーティング法、エアーナイフコーティング法、カーテンコーティング法等の通常の方法を用いることができる。ただし、１回の塗布により必要な膜厚が得られない場合、複数回重ね塗布することにより必要な膜厚を得ることができる。複数回の重ね塗布を行なう場合、加熱処理は塗布の度に行なっても良いし、複数回重ね塗布した後でも良い。
【０１９０】
次に単層型感光層について説明する。単層型感光層は、電荷発生物質、電荷輸送物質及び結着樹脂を含有して構成される。この単層型感光層は、上記式（１）で表される吸光度Ａ_１又は上記式（２）で表される吸光度Ａ_２が０．５以上のものである。このような吸光度は、上記電荷発生層５と同様の方法で測定することができる。
【０１９１】
また、電荷発生物質、電荷輸送物質及び結着樹脂としては、上記電荷発生層５、上記電荷輸送層６に用いられる電荷発生物質、電荷輸送物質及び結着樹脂と同様のものを用いることができる。単層型感光層中の電荷発生物質の含有量は、電荷発生物質と結着樹脂との合計量を基準として、好ましくは２０重量％以上、より好ましくは３０重量％以上である。また、電荷輸送物質の含有量は、感光層の構成材料の合計量を基準として、５〜５０重量％とすることが好ましい。塗布に用いる溶剤や塗布方法は、上記電荷発生層５と同様の方法で行うことができる。
【０１９２】
この単層型感光層の膜厚は、上記吸光度の条件を満たせば特に制限されないが、５〜５０μｍが好ましく、１０〜４０μｍがより好ましい。
【０１９３】
このように第１実施形態においては、吸光度が特定条件を満たす第一又は第二の金属フタロシアニン含有層を備える電子写真感光体１２を用いることによって、キャビティーの容積が小さく、アパーチャーを使用するために発光量が少ないマルチビーム方式の露光装置１４を用いた場合であっても、画像形成プロセスの高速化と画質の向上との双方が実現可能となる。
【０１９４】
また、第１実施形態の画像形成装置には、一成分系、二成分系の正規現像剤又は反転現像剤とも合わせて用いることができ、粉砕法、重合法により製造された現像剤（所定の平均形状指数のトナーを用いることが好ましい）も使用できる。また、帯電ローラーや帯電ブラシを用いた接触帯電方式、及び中間転写体を用いた転写方式においても、良好な電子写真特性、画質特性を得ることができる。
【０１９５】
次に本発明の第２実施形態について説明する。図１１は本発明の画像形成装置の第２実施形態を示す概略構成図である。図１１に示す画像形成装置２００は中間転写方式の画像形成装置であり、ハウジング４００内において４つの電子写真感光体４０１ａ〜４０１ｄ（例えば、電子写真感光体４０１ａがイエロー、電子写真感光体４０１ｂがマゼンタ、電子写真感光体４０１ｃがシアン、電子写真感光体４０１ｄがブラックの色からなる画像をそれぞれ形成可能である）が中間転写ベルト４０９に沿って相互に並列に配置されている。ここで、画像形成装置２００に搭載されている電子写真感光体４０１ａ〜４０１ｄは、それぞれドラム状の導電性基体の外周面に感光層を備えるものであり、感光層における電荷発生層（単層型の場合は、感光層）の吸光度が特定条件を満たすものである。
【０１９６】
電子写真感光体４０１ａ〜４０１ｄのそれぞれは所定の方向（紙面上は反時計回り）に回転可能であり、その回転方向に沿って帯電ロール４０２ａ〜４０２ｄ、現像装置４０４ａ〜４０４ｄ、１次転写ロール４１０ａ〜４１０ｄ、クリーニングブレード４１５ａ〜４１５ｄが配置されている。現像装置４０４ａ〜４０４ｄのそれぞれにはトナーカートリッジ４０５ａ〜４０５ｄに収容されたブラック、イエロー、マゼンタ、シアンの４色のトナーが供給可能であり、また、１次転写ロール４１０ａ〜４１０ｄはそれぞれ中間転写ベルト４０９を介して電子写真感光体４０１ａ〜４０１ｄに当接している。
【０１９７】
さらに、ハウジング４００内の所定の位置には面発光レーザアレイを光源に用いた露光装置４０３が配置されており、露光装置４０３から出射されたレーザー光を帯電後の電子写真感光体４０１ａ〜４０１ｄの表面に照射することが可能となっている。これにより、電子写真感光体４０１ａ〜４０１ｄの回転工程において帯電、露光、現像、１次転写、クリーニングの各工程が順次行われ、各色のトナー像が中間転写ベルト４０９上に重ねて転写される。
【０１９８】
中間転写ベルト４０９は駆動ロール４０６、バックアップロール４０８及びテンションロール４０７により所定の張力をもって支持されており、これらのロールの回転によりたわみを生じることなく回転可能となっている。また、２次転写ロール４１３は、中間転写ベルト４０９を介してバックアップロール４０８と当接するように配置されている。バックアップロール４０８と２次転写ロール４１３との間を通った中間転写ベルト４０９は、例えば駆動ロール４０６の近傍に配置されたクリーニングブレード４１６により清浄面化された後、次の画像形成プロセスに繰り返し供される。
【０１９９】
また、ハウジング４００内の所定の位置にはトレイ（被転写体トレイ）４１１が設けられており、トレイ４１１内の紙等の被転写体５００が移送ロール４１２により中間転写ベルト４０９と２次転写ロール４１３との間、さらには相互に当接する２個の定着ロール４１４の間に順次移送された後、ハウジング４００の外部に排紙される。
【０２００】
なお、上述の説明においては中間転写体として中間転写ベルト４０９を使用する場合について説明したが、中間転写体は、上記中間転写ベルト４０９のようにベルト状であってもよく、ドラム状であってもよい。
【０２０１】
【実施例】
以下、実施例及び比較例に基づいて本発明を更に具体的に説明するが、本発明は以下の実施例に何ら限定されるものではない。
【０２０２】
（実施例１）
酸化亜鉛（平均粒子径７０ｎｍ：テイカ社製試作品）１００重量部とトルエン５００重量部とを混合攪拌し、シランカップリング剤（ＫＢＭ６０３：信越化学社製）１．５重量部を添加してさらに２時間攪拌した。その後、トルエンを減圧蒸留で留去し、１５０℃で２時間焼き付けを行った。
【０２０３】
上記表面処理を施した酸化亜鉛６０重量部、硬化剤であるブロック化イソシアネート（スミジュール３１７５：住友バイエルンウレタン社製）１５重量部、及びブチラール樹脂（ＢＭ−１：積水化学社製）１５重量部をメチルエチルケトン８５重量部に溶解した。その溶液３８重量部とメチルエチルケトン２５重量部とを混合し、１ｍｍφのガラスビーズを用いてサンドミルにて２時間の分散し、分散液を得た。
【０２０４】
得られた分散液に触媒としてジオクチルスズジラウレート０．００５重量部を添加し、下引き層形成用塗布液を得た。この塗布液を浸漬塗布法にて直径３０ｍｍ、長さ３４０ｍｍ、肉厚１ｍｍのアルミニウム基材上に塗布し、１６０℃で１００分の乾燥硬化を行い、厚さ２０μｍの下引き層を得た。
【０２０５】
電荷発生物質としてＣｕＫα線を用いたＸ線回折スペクトルのブラッグ角（２θ±０．２°）において少なくとも７．６°及び２８．２°の位置に回折ピークを有するヒドロキシガリウムフタロシアニン顔料４重量部、結着樹脂として塩化ビニル・酢酸ビニル共重合体樹脂（ＶＭＣＨ、日本ユニカー社製）６重量部、及びｎ−ブチルアルコール３００重量部からなる混合物を、１ｍｍφのガラスビーズを用いてサンドミルにて４時間分散した。得られた分散液を電荷発生層形成用塗布液として下引き層上に浸漬塗布して乾燥し、半導体レーザー（波長：７８０ｎｍ）での吸光度が０．５の電荷発生層を形成した。この電荷発生層の膜厚は、０．２μｍであった。電荷発生層に関する各データを表２に示す。
【０２０６】
上記電荷発生層の吸光度の測定に際し、先ず、透明基材（ガラスプレート）上に上記と同様の電荷発生層形成用塗布液を用いて０．２μｍの電荷発生層を形成した。次に、分光光度計Ｕ−２０００（ＨＩＴＡＣＨＩ社製）を用いて透明基材と電荷発生層からなる積層体の透過光量Ｔ_ｂ（＝Ｔ）を測定し、その透過光量Ｔと入射光量Ｔ_０を上記式（１）に当てはめて吸光度を求めた。なお、透明基材は、波長７８０ｎｍの光の吸収がほとんどないものであった。
【０２０７】
次に、電荷輸送物質として下記式（ＩＶ）で示される化合物４重量部と結着樹脂としてビスフェノールＺ型ポリカーボネート樹脂（分子量４万）６重量部との混合物に、テトラヒドロフラン８０重量部及び２，６−ジ−ｔ−ブチル−４−メチルフェノール０．２重量部を加えて溶解した。この溶液を電荷発生層上に塗布して１２０℃で４０分の乾燥し、膜厚２８μｍの電荷輸送層を形成し、電子写真感光体を作製した。
【０２０８】
【化２４】

【０２０９】
このようにして得られた感光層が下引き層、電荷発生層及び電荷輸送層の三層からなる電子写真感光体を用いて、図１に示す構成を有する画像形成装置（富士ゼロックス社製、ＤｏｃｕＣｅｎｔｒｅ５００増速改造機（白黒１１０Ｐｒｉｎｔ／分・Ａ４））を作製した。なお、露光装置としては、面発光レーザアレイの発光点が６×６に二次元に配列され、レーザビーム数が３２本であり、走査線数が２４００ｄｐｉのものを用いた。また、トナーには形状係数ＳＦ１の平均値が１１８のものを用いた。
【０２１０】
（実施例２）
実施例１において、電荷発生物質の使用量を５重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度が０．７の電荷発生層を形成したこと以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１１】
（実施例３）
実施例１において、電荷発生物質の使用量を６重量部、結着樹脂の使用量を４重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度が１．０の電荷発生層を形成したこと以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１２】
（実施例４）
実施例１において、電荷発生物質の使用量を６重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度０．５の電荷発生層を形成した以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１３】
（実施例５）
実施例１において、電荷発生物質をＣｕＫα線を用いたＸ線回折スペクトルのブラッグ角（２θ±０．２°）において、少なくとも７．４°、１６．６°、２５．５°、２８．３°の位置に回折ピークを有するクロロガリウムフタロシアニン顔料とし、半導体レーザー（波長：７８０ｎｍ）での吸光度０．５の電荷発生層を形成した以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１４】
（実施例６）
実施例５において、電荷発生物質の使用量を５重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度０．７の電荷発生層を形成した以外は実施例５と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１５】
（実施例７）
実施例５において、電荷発生物質の使用量を６重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度１．０の電荷発生層を形成した以外は実施例５と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１６】
（実施例８）
実施例５において、電荷発生物質の使用量を６重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度０．５の電荷発生層を形成した以外は実施例５と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１７】
（実施例９）
実施例１において、電荷発生物質をＣｕＫα線を用いたＸ線回折スペクトルのブラッグ角（２θ±０．２°）において、少なくとも２７．３°の位置に回折ピークを有するオキシチタニルフタロシアニン顔料とし、半導体レーザー（波長：７８０ｎｍ）での吸光度０．５の電荷発生層を形成した以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１８】
（実施例１０）
実施例９において、電荷発生物質の使用量を５重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度０．７の電荷発生層を形成した以外は実施例９と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２１９】
（実施例１１）
実施例９において、電荷発生物質の使用量を６重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度が１．０の電荷発生層を形成した以外は実施例９と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２０】
（実施例１２）
実施例９において、電荷発生物質の使用量を６重量部、結着樹脂の使用量を５重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度が０．５の電荷発生層を形成した以外は実施例９と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表２に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２１】
（比較例１）
実施例１において、電荷発生物質３重量部、結着樹脂７重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度が０．４の電荷発生層を形成したこと以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを表３に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２２】
（比較例２）
実施例１において、電荷発生層の膜厚を変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度が０．４の電荷発生層を形成したこと以外は実施例１と同様にして感光体を作製した。電荷発生層に関する各データを表３に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２３】
（比較例３）
実施例５において、電荷発生物質３重量部、結着樹脂７重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度０．４の電荷発生層を形成したこと以外は実施例５と同様にして感光体を作製した。電荷発生層に関する各データを実施例１と同様に表３に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２４】
（比較例４）
実施例５において、電荷発生層の膜厚を変え、半導体レーザー（波長：７８０ｎｍ）での吸光度０．４の電荷発生層を形成したこと以外は実施例５と同様にして感光体を作製した。電荷発生層に関する各データを表３に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２５】
（比較例５）
実施例９において、電荷発生物質３重量部、結着樹脂７重量部に変更し、半導体レーザー（波長：７８０ｎｍ）での吸光度０．４の電荷発生層を形成したこと以外は実施例９と同様にして感光体を作製した。電荷発生層に関する各データを表３に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２６】
（比較例６）
実施例９において、電荷発生層の膜厚を変え、半導体レーザー（波長：７８０ｎｍ）での吸光度０．４の電荷発生層を形成したこと以外は実施例９と同様にして感光体を作製した。電荷発生層に関する各データを表３に示す。また、その電子写真感光体を用いて、実施例１と同様の画像形成装置を作製した。
【０２２７】
［画質の評価］
実施例１〜１３及び比較例１〜６の画像形成装置を用いて、プロセス速度１２０ｍｍ／ｓで印字テストを常温常湿（２０℃、４０％ＲＨ）で行った。画質は以下の基準：
Ａ：筋状濃度むらの発生が見えないもの、
Ｂ：筋状濃度むらの発生が見えないか軽微なもの、
Ｃ：筋状濃度むらの発生が顕著なもの、
に基づいて目視で評価した。得られた結果を表２及び表３に示す。このときの用紙としては、富士ゼロックス株式会社製ＰＰＣ用紙（Ｌ、Ａ４）を用いた。
【０２２８】
【表２】

【０２２９】
【表３】

【０２３０】
【発明の効果】
以上説明した通り、本発明の画像形成装置によれば、レーザの本数を数多くできる面発光レーザアレイを用いた場合であっても筋状の濃度ムラの発生を十分に抑制することができ、画像形成速度の高速化と画質の向上との双方が実現可能となる。
【図面の簡単な説明】
【図１】本発明の画像形成装置の第１実施形態を示す概略構成図である。
【図２】本発明にかかる露光装置（光走査装置）の一例を示す概略構成図である。
【図３】発光点が２次元的に配列されたレーザアレイを示す平面図である。
【図４】本発明にかかる制御装置の一例を示す概略構成図である。
【図５】本発明にかかる電子写真感光体の一例を示す模式断面図である。
【図６】本発明にかかる電子写真感光体の一例を示す模式断面図である。
【図７】本発明にかかる電子写真感光体の一例を示す模式断面図である。
【図８】本発明にかかる電子写真感光体の一例を示す模式断面図である。
【図９】機能分離型感光体の電荷発生層の吸光度と、当該感光体の一重露光領域と多重露光領域との電位差と、の相関の一例を示すグラフである。
【図１０】機能分離型感光体の電荷発生層における電荷発生物質と結着樹脂との比と、当該感光体の一重露光領域と多重露光領域との電位差と、の相関の一例を示すグラフである。
【図１１】本発明の画像形成装置の第２実施形態を示す概略構成図である。
【図１２】電子写真感光体の移動方向（副走査方向）に沿った露光エネルギーの分布を示すグラフである。
【図１３】一重露光領域と多重露光領域との濃度ムラを示す模式図である。
【符号の説明】
２…導電性支持体、３…感光層、４…下引き層、５…電荷発生層、６…電荷輸送層、７…保護層、１００…画像形成装置、１２…電子写真感光体、１４…帯電器、１６…露光装置、１８…現像装置、２４…中間転写ベルト、３２，４２…転写器、４４…定着器、５０…面発光レーザアレイ、５１…発光点、５２…コリメートレンズ、５４…ハーフミラー、５６…レンズ、５８…光量センサ、６０…アパーチャ、６２…シリンダレンズ、６４…折り返しミラー、６６…回転多面鏡、６８，７０…Ｆθレンズ、７２，７４…シリンダミラー、７６…ピックアップミラー、７８…ビーム位置検出センサ、８０…制御部、８２…記憶部、８４…変調信号生成手段、８８…駆動量制御手段、９２…レベル変更手段、９４…光量差設定手段、２００…画像形成装置、４００…ハウジング、４０２ａ〜４０２ｄ…帯電ロール、４０３…露光装置、４０４ａ〜４０４ｄ・・・現像装置、４０５ａ〜４０５ｄ…トナーカートリッジ、４０６…駆動ロール、４０７…テンションロール、４０８…バックアップロール、４０９…中間転写ベルト、４１０ａ〜４１０ｄ…１次転写ロール、４１１…トレイ（被転写体トレイ）、４１２…移送ロール、４１３…２次転写ロール、４１４…定着ロール、４１５ａ〜４１５ｄ…クリーニングブレード、４１６…クリーニングブレード、５００…被転写体。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms an image by an electrophotographic process including charging, exposure, development, transfer, and the like.
[0002]
[Prior art]
In an electrophotographic image forming apparatus, as a method of forming an electrostatic latent image on a charged electrophotographic photosensitive member, a method of scanning a plurality of light beams on the electrophotographic photosensitive member (hereinafter referred to as “multi-beam method”). )It has been known. (For example, see Patent Documents 1 to 4).
[0003]
[Patent Document 1]
JP 2002-303997 A
[Patent Document 2]
JP 2002-107988 A
[Patent Document 3]
JP 2002-251023 A
[Patent Document 4]
JP 11-188922 A
[0004]
[Problems to be solved by the invention]
Such a multi-beam type image forming apparatus is considered to be effective for speeding up the image forming process, but it is not always sufficient in terms of image quality, and in particular, a surface emitting laser array that can increase the number of lasers. It becomes a problem when used. That is, in the electrostatic latent image formed on the electrophotographic photosensitive member, there are mixed regions where the number of times the light beam is scanned (irradiation number) until the end of exposure, and the difference in the number of irradiation times between the regions is different on the image. May be visually recognized as streaky density unevenness.
[0005]
FIG. 12 shows scanning of 30 scanning lines (scanning line density of 2600 dpi) at the same time by scanning 30 laser beams each having a spot diameter of 50 μm on the electrophotographic photosensitive member. Is a graph showing the distribution of exposure energy along the moving direction (sub-scanning direction) of the electrophotographic photosensitive member when the electrophotographic photosensitive member is moved and the scanning lines are shifted by 30 lines each time. is there.
[0006]
As shown in the drawing, the exposure energy distribution in each main scanning is substantially trapezoidal. Of the exposure energy distribution given to the electrophotographic photosensitive member by each main scanning, the flat portion of the energy distribution corresponding to the top of the trapezoid is a region where the entire exposure energy is applied by one exposure (single exposure region). On the other hand, the portion corresponding to the skirt of the trapezoid is a region (multiple exposure region) where the total exposure energy is applied by two exposures.
[0007]
According to the study by the present inventors, even in the case where the total exposure energy of the multiple exposure region is equal to the total exposure energy of the single exposure region, the multiple exposure region is more than the single exposure region in the actually obtained image. Also, the image density becomes high and streaky density unevenness as shown in FIG. 13 occurs.
[0008]
The present invention has been made in view of the above-described problems of the prior art, and sufficiently suppresses the occurrence of streaky density unevenness even when a surface emitting laser array capable of increasing the number of lasers is used. An object of the present invention is to provide an image forming apparatus that can achieve both improvement in image quality and increase in image forming speed.
[0009]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors generate streak density unevenness when a conventional electrophotographic photosensitive member is used in an image forming apparatus equipped with a multi-beam exposure apparatus. It has been found that the problem is caused by the potential difference between the single exposure region and the multiple exposure region after exposure. Even if the potential difference is of a level that does not cause a problem when the multi-beam method is not applied, the potential difference becomes apparent as stripe-like density unevenness when the multi-beam method is applied.
[0010]
Accordingly, the present inventors have further studied a technique for suppressing a potential difference between a single exposure region and a multiple exposure region of a photosensitive member applied to a multi-beam type image forming apparatus. As a result, a metal phthalocyanine-containing layer was provided on the photoreceptor, and the light-absorbing property of the metal phthalocyanine-containing layer was found to satisfy the specific condition, and the present invention was completed. .
[0011]
That is, the image forming apparatus of the present invention exposes an electrophotographic photosensitive member having a conductive substrate and a photosensitive layer formed on the substrate, a charging device for charging the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member. An exposure device for forming an electrostatic latent image, a developing device for developing the electrostatic latent image with toner to form a toner image, a transfer device for transferring the toner image from the electrophotographic photosensitive member to a transfer medium, The exposure apparatus is equipped with a surface emitting laser array having three or more light emitting elements as an exposure light source, and adopts a multi-beam method in which a plurality of light beams are scanned on an electrophotographic photosensitive member to form an electrostatic latent image. The photosensitive layer contains a metal phthalocyanine and has an absorbance A represented by the following formula (1):₁It has the 1st metal phthalocyanine content layer which is 0.5 or more.
A₁= Log₁₀(T₀/ T) (1)
[T in formula (1)₀And T represent the incident light amount and transmitted light amount of the light beam, respectively. ]
[0012]
Further, the first metal phthalocyanine-containing layer in the photosensitive layer contains an absorbance A containing metal phthalocyanine and represented by the following formula (2).₂The second metal phthalocyanine-containing layer may be 0.5 or more.
A₂= (1/2) · log₁₀(R₀/ R) (2)
[In the formula (2), R represents a light beam from the side of the second metal phthalocyanine-containing layer to the first irradiated object except the layer farther from the substrate than the second metal phthalocyanine-containing layer from the photoreceptor. Indicates the amount of reflected light when irradiated, R₀Represents the amount of reflected light when the second irradiated object obtained by removing the second metal phthalocyanine-containing layer from the first irradiated object is irradiated with the light beam from the side where the second metal phthalocyanine-containing layer is provided. . ]
[0013]
In addition, by using an electrophotographic photosensitive member provided with the first metal phthalocyanine-containing layer or the second metal phthalocyanine-containing layer, the potential difference between the single exposure region and the multiple exposure region when performing multi-beam exposure can be suppressed. Although the reason is not necessarily clear, the present inventors infer as follows.
[0014]
That is, by providing the first metal phthalocyanine-containing layer or the second metal phthalocyanine-containing layer whose absorbance satisfies the above-mentioned specific conditions, the ratio of absorbing light is sufficiently increased, so that an exposure beam for obtaining the same sensitivity Can reduce the energy. As a result, the amount of charge separation (carrier generation) per unit charge generating substance is reduced, and the probability of recombination of the generated carriers is reduced. Therefore, it is considered that the potential difference between the single exposure region and the multiple exposure region is suppressed. .
[0015]
In the present invention, in the first metal phthalocyanine-containing layer or the second metal phthalocyanine-containing layer, the content of the charge generating material containing metal phthalocyanine is 40% by weight based on the total amount of the charge generating material and the binder resin. % Or more is preferable. In this case, the potential difference between the single exposure region and the multiple exposure region can be further suppressed.
[0016]
The preferred embodiment described above is an embodiment in which the first metal phthalocyanine-containing layer or the second metal phthalocyanine-containing layer is formed by vapor deposition of a charge generating material, that is, the first metal phthalocyanine-containing layer or the second metal. An embodiment in which the phthalocyanine-containing layer does not contain a binder resin (an embodiment in which the content of the charge generation material in the metal phthalocyanine-containing layer is 100%) is included.
[0017]
Moreover, in this invention, it is preferable that a 1st metal phthalocyanine containing layer or a 2nd metal phthalocyanine containing layer is set to 0.1-0.5 micrometer.
[0018]
In the present invention, the metal phthalocyanine is preferably at least one selected from hydroxygallium phthalocyanine, chlorogallium phthalocyanine, and oxytitanyl phthalocyanine. By using the specific metal phthalocyanine, the sensitivity of the electrophotographic photosensitive member can be further increased, and the image forming speed can be increased and the image quality can be improved at a higher level.
[0019]
In the present invention, it is preferable that the resolution is 1200 dpi or more and the process speed is 100 mm / s or more. When the resolution or process speed is increased, the density unevenness tends to occur normally. However, by adopting the configuration of the present invention, such a problem does not occur, and both improvement in image quality and increase in image formation speed can be realized.
[0020]
In the present invention, the average value of the shape factor SF1 of the toner is preferably 115 to 140. This toner is excellent in faithful image quality reproducibility, and it is possible to further improve the image quality.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.
[0022]
FIG. 1 is a schematic configuration diagram showing a first embodiment according to the image forming apparatus of the present invention. The image forming apparatus 100 shown in FIG. 1 includes an electrophotographic electrophotographic photosensitive member 12, and the electrophotographic photosensitive member 12 can be rotated in the direction of arrow A at a predetermined rotational speed by a driving device (not shown). ing. The electrophotographic photosensitive member 12 has a photosensitive layer provided on the outer peripheral surface of a drum-shaped conductive substrate. The photosensitive layer contains metal phthalocyanine and is represented by the following formula (1) or (2). The first or second metal phthalocyanine layer having an absorbance of 0.5 or more is included.
A₁= Log₁₀(T₀/ T) (1)
[T in formula (1)₀And T represent the incident light amount and transmitted light amount of the light beam, respectively. ]
A₂= (1/2) · log₁₀(R₀/ R) (2)
[In Formula (2), R irradiates a light beam from the second metal phthalocyanine layer side to the first object to be irradiated, excluding the layer farther from the substrate than the second metal phthalocyanine layer from the photoreceptor. Represents the amount of reflected light, and R₀Represents the amount of reflected light when the second irradiated object obtained by removing the second metal phthalocyanine layer from the first irradiated object is irradiated with the light beam from the side where the second metal phthalocyanine layer is provided. ]
[0023]
As will be described later, the electrophotographic photoreceptor 12 is a function-separated photoreceptor in which a charge generation layer and a charge transport layer are separately provided as long as the first or second metal phthalocyanine-containing layer is provided. Alternatively, it may be a single layer type photoreceptor provided with a layer containing both a charge generating substance and a charge transporting substance. In the case of a function-separated type photoreceptor, the first or second metal phthalocyanine layer functions as a charge generation layer. On the other hand, in the case of a single-layer type photoreceptor, the metal phthalocyanine layer functions as a photosensitive layer by further containing a charge transport material in the first or second metal phthalocyanine layer.
[0024]
A charger 14 for charging the outer peripheral surface of the electrophotographic photosensitive member 12 is provided substantially above the electrophotographic photosensitive member 12.
[0025]
An exposure device (light beam scanning device) 16 is disposed substantially above the charger 14. Although details will be described later, the exposure device 16 modulates three or more light beams (laser beams) emitted from a light source using a surface emitting laser array in accordance with an image to be formed, and in the main scanning direction. The outer peripheral surface of the electrophotographic photosensitive member 12 that has been deflected and charged by the charger 14 is scanned in parallel with the axis of the electrophotographic photosensitive member 12.
[0026]
A developing device 18 is disposed on the side of the electrophotographic photosensitive member 12. The developing device 18 includes a roller-shaped container that is rotatably arranged. Four containers are formed inside the container, and developing units 18Y, 18M, 18C, and 18K are provided in each container. Each of the developing units 18Y, 18M, 18C, and 18K includes a developing roller 20, and stores therein yellow (Y), magenta (M), cyan (C), and black (K) toners.
[0027]
Further, this toner preferably has an average value of the shape factor SF1 of 115 to 140. This shape factor SF1 can be obtained by the following equation.
SF1 = (π / 4) × (ML²/ A) × 100
(However, ML represents the maximum length of the toner particle diameter, and A represents the projected area.)
[0028]
This shape factor is obtained by dispersing toner on a slide glass, taking an image observed with an optical microscope into a Luzex image analyzer through a video camera, measuring the maximum length and projected area of 100 or more toner particles, and substituting them into the above formula. The average value was taken as the average value of the shape factor. When the toner having such a shape is used, developability, transferability, and image quality can be improved.
[0029]
An endless intermediate transfer belt 24 is disposed substantially below the electrophotographic photosensitive member 12. The intermediate transfer belt 24 is wound around rollers 26, 28, and 30, and is disposed so that the outer peripheral surface is in contact with the outer peripheral surface of the electrophotographic photosensitive member 12. The rollers 26 to 30 are rotated by the driving force of a motor (not shown) being transmitted, and rotate the intermediate transfer belt 24 in the direction of arrow B.
[0030]
A transfer device 32 is disposed on the opposite side of the electrophotographic photosensitive member 12 with the intermediate transfer belt 24 interposed therebetween. The toner image formed on the outer peripheral surface of the electrophotographic photosensitive member 12 is transferred to the image forming surface of the intermediate transfer belt 24 by the transfer device 32.
[0031]
A tray 34 is disposed below the intermediate transfer belt 24, and a large number of sheets P as recording materials are accommodated in the tray 34 in a stacked state. In FIG. 1, a take-out roller 36 is disposed obliquely above and to the left of the tray 34, and a roller pair 38 and a roller 40 are sequentially arranged on the downstream side in the take-out direction of the paper P by the take-out roller 36. The uppermost recording paper in the stacked state is taken out of the tray 34 by the rotation of the take-out roller 36 and is conveyed by the roller pair 38 and the roller 40.
[0032]
A transfer device 42 is disposed on the opposite side of the roller 30 with the intermediate transfer belt 24 in between. The paper P conveyed by the roller pair 38 and the roller 40 is sent between the intermediate transfer belt 24 and the transfer device 42, and the toner image formed on the image forming surface of the intermediate transfer belt 24 is transferred by the transfer device 42. . A fixing device 44 having a pair of fixing rollers is arranged downstream of the transfer device 42 in the conveyance direction of the paper P. The paper P on which the toner image is transferred is transferred to the paper P by the fixing device 44. After being fused and fixed, the sheet is discharged out of the image forming apparatus 100 and placed on a discharge tray (not shown). The fixing device 44 corresponds to the fixing means described in claim 1.
[0033]
Further, on the opposite side of the developing device 18 across the electrophotographic photosensitive member 12, there is a function of removing static electricity on the outer peripheral surface of the electrophotographic photosensitive member 12 and a function of removing unnecessary toner remaining on the outer peripheral surface. A cleaner 22 is disposed. When the toner image formed on the outer peripheral surface of the electrophotographic photosensitive member 12 is transferred to the intermediate transfer belt 24, the region carrying the transferred toner image on the outer peripheral surface of the electrophotographic photosensitive member 12 is neutralized. -It is cleaned by the cleaner 22.
[0034]
Thus, every time the electrophotographic photosensitive member 12 rotates, toner images of Y, M, C, and K are sequentially formed on the outer peripheral surface of the electrophotographic photosensitive member 12 so as to overlap each other. When the electrophotographic photosensitive member 12 rotates four times, a full-color toner image is formed on the outer peripheral surface of the electrophotographic photosensitive member 12.
[0035]
In this way, together with the multi-beam type exposure device 14 that scans a plurality of light beams on the electrophotographic photosensitive member to form an electrostatic latent image, the absorbance of the metal phthalocyanine-containing layer satisfies the above specific condition. By using the body 12, even if there are regions where the number of times of irradiation of the light beam is different in the electrostatic latent image, the density is sufficiently uniformed, so that the occurrence of streaky density unevenness can be sufficiently suppressed. Thus, both speeding up of the image forming process and improvement of image quality can be realized.
[0036]
Next, preferred examples of the exposure device 16 and the electrophotographic photoreceptor 12 will be described in detail.
[0037]
(Exposure equipment)
First, a preferred example of the exposure apparatus 16 will be described in detail with reference to FIG. The exposure apparatus 16 includes a surface emitting laser array 50 that emits m (m is at least 3) laser beams. In FIG. 2, only three laser beams are shown for simplification, but a surface emitting laser array 50 formed by arraying surface emitting lasers is configured to emit several tens of laser beams. In addition, the arrangement of the surface emitting lasers (arrangement of the laser beams emitted from the surface emitting laser array 50) may be arranged two-dimensionally (for example, in a matrix) in addition to the arrangement in one column. Is also possible.
[0038]
FIG. 3 is a plan view showing a laser array 50 in which light emitting points are two-dimensionally arranged. As shown in the drawing, a total of 16 light emitting points 51 are arranged two-dimensionally in the laser array 50 at predetermined intervals, four in the main scanning direction and four in the sub-scanning direction. Further, the light emitting points 51 arranged in the main scanning direction are arranged so that the distance obtained by dividing the distance from the light emitting point 51 adjacent in the sub scanning direction into four equal parts is one step, and the step is shifted step by step in the sub scanning direction. Has been. That is, when viewed in the sub-scanning direction, the light emission points 51 are arranged for each step. In this way, by arranging the light emitting points 51 while being shifted stepwise in the sub-scanning direction, all the light emitting points 51 can scan different scanning lines. As a result, the laser array 50 scans 16 scanning lines simultaneously.
[0039]
Returning to FIG. 2, a collimating lens 52 and a half mirror 54 are sequentially arranged on the laser beam emission side of the surface emitting laser array 50. The laser beam emitted from the surface emitting laser array 50 is made into a substantially parallel light beam by the collimator lens 52 and then incident on the half mirror 54, and a part of the laser beam is separated and reflected by the half mirror 54. A lens 56 and a light amount sensor 58 are arranged in this order on the laser beam reflecting side of the half mirror 54, and a part of the laser beam separated and reflected from the main laser beam (laser beam used for exposure) by the half mirror 54 is The light passes through the lens 56 and enters the light quantity sensor 58, and the light quantity is detected by the light quantity sensor 58.
[0040]
In addition, since the surface emitting laser does not emit a laser beam from the side opposite to the side from which the laser beam used for exposure is emitted (in the case of an edge emitting laser, it is emitted from both sides). Therefore, it is necessary to separate a part of the laser beam used for exposure as described above and use it for light quantity detection.
[0041]
An aperture 60, a cylinder lens 62 having power only in the sub-scanning direction, and a folding mirror 64 are arranged in this order on the main laser beam emission side of the half mirror 54, and the main laser beam emitted from the half mirror 54 is emitted from the aperture 60. Then, the light is refracted by the cylinder lens 62 so as to form a long linear image in the main scanning direction in the vicinity of the reflection surface of the rotary polygon mirror 66, and reflected by the folding mirror 64 to the rotary polygon mirror 66 side. Note that the aperture 60 is desirably disposed in the vicinity of the focal position of the collimating lens 52 in order to uniformly shape a plurality of laser beams.
[0042]
The rotating polygon mirror 66 is rotated in the direction of arrow C in FIG. 2 by the driving force of a motor (not shown), and deflects and reflects the incident laser beam reflected by the folding mirror 64 along the main scanning direction. . Fθ lenses 68 and 70 having power only in the main scanning direction are arranged on the laser beam emission side of the rotary polygon mirror 66, and the laser beam deflected and reflected by the rotary polygon mirror 66 is applied to the electrophotographic photosensitive member 12. It is refracted by the Fθ lenses 68 and 70 so that it moves on the outer peripheral surface at a substantially constant speed and the image forming position in the main scanning direction coincides with the outer peripheral surface of the electrophotographic photosensitive member 12.
[0043]
Cylinder mirrors 72 and 74 having power only in the sub-scanning direction are sequentially arranged on the laser beam emission side of the Fθ lenses 68 and 70, and the laser beams transmitted through the Fθ lenses 68 and 70 are connected in the sub-scanning direction. The image position is reflected by the cylinder mirrors 72 and 74 so as to coincide with the outer peripheral surface of the electrophotographic photosensitive member 12 and is irradiated on the outer peripheral surface of the photosensitive drum 12. The cylinder mirrors 72 and 74 also have a surface tilt correction function that conjugates the outer peripheral surfaces of the rotary polygon mirror 66 and the electrophotographic photosensitive member 12 in the sub-scanning direction.
[0044]
A pickup mirror 76 is disposed on the laser beam emission side of the cylinder mirror 72 at a position corresponding to an end (SOS: Start Of Scan) of the scanning range of the laser beam. A beam position detection sensor 78 is arranged on the laser beam emission side. When the laser beam emitted from the surface emitting laser array 50 reflects the incident beam in a direction corresponding to the SOS, the reflecting surface of the rotary polygon mirror 66 reflects the laser beam. Then, it is reflected by the pickup mirror 76 and enters the beam position detection sensor 78 (see also the imaginary line in FIG. 2).
[0045]
The signal output from the beam position detection sensor 78 modulates the laser beam scanned on the outer peripheral surface of the electrophotographic photosensitive member 12 as the rotary polygon mirror 66 rotates to form an electrostatic latent image each time. This is used to synchronize the modulation start timing in the main scanning.
[0046]
In the exposure apparatus 16 according to this embodiment, the collimator lens 52, the cylinder lens 62, and the two cylinder mirrors 72 and 74 are arranged so as to be afocal in the sub-scanning direction. This is to suppress the difference in the scanning line curvature (BOW) of the plurality of laser beams and the variation in the scanning line interval due to the plurality of laser beams.
[0047]
Next, in the control device of the image forming apparatus 100, the configuration of a portion that controls the emission of the laser beam from the surface emitting laser array 50 of the exposure device 16 (hereinafter, this portion is referred to as a control unit 80) is shown in FIG. Will be described with reference to FIG. The control device includes a storage unit 82 for storing image data representing an image to be formed by the image forming apparatus 100, and the image data stored in the storage unit 82 is formed by the image forming apparatus 100. Is input to the modulation signal generating means 84 of the control unit 80.
[0048]
Although not shown, a beam position detection sensor 78 is connected to the modulation signal generation means 84. The modulation signal generation unit 84 decomposes the image data input from the storage unit 82 into m pieces of image data respectively corresponding to any of the m laser beams emitted from the surface emitting laser array 50 and decomposes the image data. Based on the m pieces of image data, the timing at which each of the m laser beams emitted from the surface emitting laser array 50 is turned on and off is based on the SOS timing detected by the signal input from the beam position detection sensor 78. M modulation signals to be defined are generated and output to a laser driving circuit (LDD) 86.
[0049]
The LDD 86 is connected with drive amount control means 88 (details will be described later), and the m laser beams emitted from the surface emitting laser array 50 are timed according to the modulation signal input from the modulation signal generation means 84. And turning on and off, and generating m number of drive currents for making the light amount of the laser beam at the time of on the light amount corresponding to the drive amount setting signal inputted from the drive amount control means 88, so that the surface emitting laser array 50 Each is supplied to m surface emitting lasers.
[0050]
As a result, the surface emitting laser array 50 emits m laser beams that are turned on and off at a timing corresponding to the modulation signal, and whose light amount when turned on is a light amount corresponding to the drive amount setting signal. Each of the laser beams is scanned and exposed on the outer peripheral surface of the electrophotographic photosensitive member 12, whereby an electrostatic latent image is formed on the outer peripheral surface of the electrophotographic photosensitive member 12. The electrostatic latent image is developed as a toner image by the developing device 18, the toner image is transferred to the paper P after being transferred by the transfer devices 32 and 42, and is fused and fixed to the paper P by the fixing device 44. An image is recorded in P.
[0051]
On the other hand, the image forming apparatus 10 is one of a toner image formed on the outer peripheral surface of the electrophotographic photosensitive member 12, a toner image transferred on the outer peripheral surface of the intermediate transfer belt 24, and an image recorded on the paper P. A density sensor (not shown) for detecting the density of the liquid is provided, and this density sensor is connected to the control unit 80. In the case where an image (specifically, an electrostatic latent image) is formed by simultaneously scanning and exposing a large number (m) of laser beams on the outer peripheral surface of the electrophotographic photosensitive member 12 as in the present embodiment, each time The laser beam is irradiated (exposed) twice near the boundary of the scanning region by m laser beams in the main scanning.
[0052]
(Electrophotographic photoreceptor)
Next, a preferred example of the electrophotographic photoreceptor 12 will be described in detail. 5 to 8 are schematic cross-sectional views each showing a preferred example of the electrophotographic photosensitive member 12. The electrophotographic photosensitive member shown in FIGS. 5 to 8 includes a layer containing a charge generating substance (charge generating layer 5) and a charge. The photosensitive layer 3 is separated in function from a layer containing a transport material (charge transport layer 6).
[0053]
The electrophotographic photoreceptor 12 shown in FIG. 5 has a structure in which a charge generation layer 5 and a charge transport layer 6 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 12 shown in FIG. 6 has a structure in which an undercoat layer 4, a charge generation layer 5, and a charge transport layer 6 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 12 shown in FIG. 7 has a structure in which a charge generation layer 5, a charge transport layer 6, and a protective layer 7 are sequentially laminated on a conductive support 2. An electrophotographic photoreceptor 12 shown in FIG. 8 has a structure in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are sequentially laminated on a conductive support 2. In these electrophotographic photoreceptors 12, the charge generation layer 5 corresponds to a first or second metal phthalocyanine layer.
[0054]
Next, each element of the electrophotographic photoreceptor 12 will be described in detail.
[0055]
As the conductive substrate 2, a metal drum made of aluminum, copper, iron, zinc, nickel or the like; on a substrate such as sheet, paper, plastic or glass, aluminum, copper, gold, silver, platinum, palladium, titanium, nickel-chromium , Stainless steel, copper-indium or other metal deposited; conductive metal compound such as indium oxide or tin oxide deposited on the substrate; metal foil laminated on the substrate; carbon black, oxidized Indium, tin oxide-antimony oxide powder, metal powder, copper iodide and the like are dispersed in a binder resin and applied on the substrate to conduct a conductive treatment. The shape of the conductive substrate 2 may be a drum shape, a sheet shape, a plate shape, or the like.
[0056]
When a metal pipe substrate is used as the conductive substrate 2, the surface of the substrate may be a raw tube, and in advance, mirror cutting, etching, anodizing, rough cutting, centerless grinding, sandblasting, wet Processing such as honing and coloring may be performed. By roughening the surface of the base material, it is possible to prevent grain-like density spots caused by interference light in the photoconductor, which may occur when a coherent light source is used.
[0057]
The undercoat layer 4 prevents injection of charges from the substrate 2 to the photosensitive layer 2 when the photosensitive layer 2 having a laminated structure is charged, and allows the photosensitive layer 2 to be bonded and held integrally with the substrate 2. It has an action as an adhesive layer. In addition, the undercoat layer 4 exhibits a light reflection preventing action of the base 2 depending on the case.
[0058]
Materials for the undercoat layer 4 include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate resin. , Vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, polymer resin compound such as melamine resin, zirconium chelate compound, titanium chelate compound, aluminum chelate compound, titanium alkoxide compound, An organic titanium compound, a silane coupling agent, etc. are mentioned. In addition, a charge transporting resin having a charge transporting group, a conductive resin such as polyaniline, or the like can be used. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, a resin insoluble in a solvent contained in the coating solution for forming the upper layer (for example, the charge generation layer 5), particularly a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, an epoxy resin, or the like is preferably used. Further, zirconium chelate compounds and silane coupling agents are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.
[0059]
As silane coupling agents, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ -Aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like. Among such silicon compounds, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl- Silane coupling agents such as 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are particularly preferably used.
[0060]
Zirconium chelate compounds include: zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthenic acid Zirconium, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.
[0061]
Titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium Examples include lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.
[0062]
Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).
[0063]
In the undercoat layer 4, a conductive substance can be contained in order to improve the photoreceptor characteristics. Examples of the conductive material include metal oxides such as titanium oxide, zinc oxide, and tin oxide, and any known material can be used as long as desired photoreceptor characteristics can be obtained.
[0064]
These metal oxides can be surface treated. By performing the surface treatment, resistance value control, dispersibility control, and improvement in photoreceptor characteristics can be achieved. As the surface treatment agent, known materials such as a zirconium chelate compound, a titanium chelate compound, an aluminum chelate compound, a titanium alkoxide compound, an organic titanium compound, and a silane coupling agent can be used. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, the silane coupling agent is excellent in performance such as low residual potential, little potential change due to environment, little potential change due to repeated use, and excellent image quality characteristics.
[0065]
Examples of the silane coupling agent, zirconium chelate compound, titanium chelate compound, and aluminum chelate compound include the same substances as described above.
[0066]
As the surface treatment method, any known method can be used, but a dry method or a wet method can be used. When surface treatment is performed by a dry method, a silane coupling agent dissolved directly or in an organic solvent is dropped while stirring the metal oxide fine particles with a mixer having a large shearing force, and the mixture is dried air or Uniform treatment is achieved by spraying with nitrogen gas. The dropping of the silane coupling agent and the spraying of the mixture are preferably performed at a temperature not higher than the boiling point of the solvent. When the dropping and spraying are performed at a temperature equal to or higher than the boiling point of the solvent, the solvent evaporates before being uniformly stirred, and the silane coupling agent is locally aggregated, making it difficult to perform uniform treatment.
[0067]
The surface-treated metal oxide particles can be further baked at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained.
[0068]
When surface treatment is performed by a wet method, the metal oxide fine particles are dispersed in a solvent by stirring or using an ultrasonic wave, a sand mill, an attritor, a ball mill or the like, and a silane coupling agent solution is added and stirred or dispersed. After that, it is processed uniformly by removing the solvent. The solvent is preferably distilled off by distillation. The removal method by filtration is not preferable because unreacted silane coupling agent tends to flow out and it is difficult to control the amount of silane coupling agent for obtaining desired characteristics. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, as a method for removing the metal oxide fine particle-containing water, a method of removing with stirring and heating in a solvent used for surface treatment, or a method of removing by azeotropic distillation with a solvent can be used.
[0069]
The amount of the silane coupling agent relative to the metal oxide fine particles in the undercoat layer 4 can be any amount as long as desired electrophotographic characteristics can be obtained. Further, the ratio between the gold image oxide fine particles and the resin used in the undercoat layer 4 can be arbitrarily set as long as desired electrophotographic characteristics can be obtained.
[0070]
Various organic or inorganic fine powders can be mixed in the undercoat layer 4 for the purpose of improving light scattering properties. Preferred examples of such fine powder include white pigments such as titanium oxide, zinc oxide, zinc sulfide, lead white, and lithopone, inorganic pigments such as extender pigments such as alumina, calcium carbonate, and barium sulfate, and Teflon (registered trademark) resin particles. , Benzoguanamine resin particles, styrene resin particles, and the like. The particle size of these fine powders is preferably 0.01 to 2 μm. The fine powder is added as necessary, but when added, it is preferably 10 to 80% by weight, and 30 to 70% by weight, based on the solid content contained in the undercoat layer 4 It is more preferable that
[0071]
Further, various additives can be used in the coating solution for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′-tetra- Examples thereof include electron transporting substances such as diphenoquinone compounds such as t-butyldiphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems.
[0072]
When preparing the coating solution for the undercoat layer, when the fine powder such as the conductive material or the light scattering material described above is mixed, the fine powder may be added to the solution in which the resin component is dissolved to perform the dispersion treatment. preferable. As a method for dispersing the fine powder in the resin, methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used. As a coating method for the coating solution for forming the undercoat layer, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.
[0073]
The thickness of the undercoat layer 4 is preferably 0.01 to 50 μm, and more preferably 0.05 to 30 μm.
[0074]
As described above, the charge generation layer 5 corresponds to the first or second metal phthalocyanine-containing layer according to the present invention, contains metal phthalocyanine as a charge generation material, and is represented by the above formula (1). Absorbance A₁Or absorbance A represented by the above formula (2)₂Is 0.5 or more. Absorbance A₁, A₂Can be controlled by appropriately selecting the type and amount of use of metal phthalocyanine, other charge generating materials, binder resin, and the like described later.
[0075]
The configuration of the present invention in which an electrophotographic photosensitive member having a first or second metal phthalocyanine-containing layer is applied to a multi-beam type image forming apparatus, and the single-exposure region and multiple-exposure region of the photosensitive member by such a configuration. The effect of the present invention that the potential difference can be suppressed is based on the inventors' knowledge that the absorbance of the metal phthalocyanine-containing layer is useful as an indicator of the potential difference. FIG. 9 shows an example of the correlation between the absorbance of the charge generation layer of the function separation type photoconductor and the potential difference between the single exposure region and the multiple exposure region of the photoconductor. In FIG. 9, although the potential difference shows a high value in the vicinity of the absorbance of 0.1, there is a critical point where the potential difference sharply decreases in the vicinity of the absorbance of 0.4, and streaky density unevenness occurs in the vicinity of the absorbance of 0.5. It can be seen that the potential difference is suppressed to the extent that it does not occur.
[0076]
Absorbance A₁Is the amount of incident light T on the charge generation layer 5₀And the measured value of the transmitted light amount T. More specifically, first, the transmitted light amount T of a transparent substrate (preferably having a low light absorption property to a light beam)._aMeasure. Next, the charge generation layer 5 having a predetermined film thickness is formed on the transparent base material, and the transmitted light amount T of the laminate comprising the transparent base material and the charge generation layer 5 is measured._bMeasure. Transmitted light amount T of this transparent substrate_aAnd the amount of transmitted light T_bIs the transmitted light amount T of the charge generation layer. The transmitted light amount T and the incident light amount T thus obtained.₀From the above equation (1), the absorbance A₁Is required. In the case where the transparent substrate does not absorb the light beam or does not substantially absorb the light beam, the transmitted light amount T of the laminated body_bCan be the transmitted light amount T.
[0077]
On the other hand, absorbance A₂Irradiates a light beam from the side of the charge generation layer 5 to the first irradiated body excluding the layer (charge transport layer 6 and protective layer 7) farther from the substrate 2 than the charge generation layer 5 from the photoconductor 12. Reflected light amount R, and reflected light amount R when the second irradiated body obtained by removing the charge generating layer 5 from the first irradiated body is irradiated with a light beam from the side where the charge generating layer 5 is provided.₀It is obtained from the measured value. More specifically, first, the amount of reflected light R of the second object to be irradiated (the conductive substrate 2 or the conductive substrate 2 and the undercoat layer 4) is reflected.₀Measure. Next, the first irradiated body is produced by forming the charge generation layer 5 having a predetermined thickness on the second irradiated body, and the reflected light amount R of the first irradiated body is measured. The amount of reflected light R thus obtained.₀And the reflected light amount R, the absorbance A based on the above equation (2)₂Is required.
[0078]
Absorbance A₂Can be measured from, for example, an electrophotographic photosensitive member 12 in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6, and a protective layer 7 are sequentially laminated on the conductive support 2. In this case, the charge transport layer 6 and the protective layer 7 are peeled off from the photoreceptor 12 to form a first irradiated body comprising the conductive support 2, the undercoat layer 4, and the charge generation layer 5, and the first coated The amount of reflected light R of the irradiated body is measured. Next, the charge generation layer 5 is peeled off to form a second irradiated body composed of the conductive support 2 and the undercoat layer 4, and the reflected light amount R of the second irradiated body.₀Measure. The amount of reflected light R thus obtained.₀And the amount of reflected light R, the absorbance A based on the above equation (2)₂Can also be requested.
[0079]
As the metal phthalocyanine according to the present invention, it is preferable to use at least one selected from hydroxygallium phthalocyanine, chlorogallium phthalocyanine and oxytitanyl phthalocyanine;
[0080]
Hydroxygallium phthalocyanine having diffraction peaks at least at positions of 7.6 ° and 28.2 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using CuKα rays, at least 7.4 °, 16 It should be at least one selected from chlorogallium phthalocyanine having diffraction peaks at positions of .6 °, 25.5 ° and 28.3 ° and oxytitanyl phthalocyanine having diffraction peaks at a position of at least 27.3 °. More preferred. By using the above metal phthalocyanine, it is possible to more reliably suppress the occurrence of stripe-like density unevenness due to the potential difference between the single exposure region and the multiple exposure region in the multi-beam type image forming apparatus.
[0081]
As a method for producing metal phthalocyanine, pigment crystals (hydroxygallium phthalocyanine pigment, chlorogallium phthalocyanine pigment, oxytitanyl phthalocyanine pigment, etc.) produced by a known method are used in an automatic mortar, planetary mill, vibration mill, CF mill, roller mill. And a method of mechanically dry pulverizing with a sand mill, a kneader or the like, or a method of performing a wet pulverization treatment using a ball mill, a mortar, a sand mill, a kneader or the like together with a solvent after the dry pulverization.
[0082]
Solvents used in the above treatment are aromatics (toluene, chlorobenzene, etc.), amides (dimethylformamide, N-methylpyrrolidone, etc.), halogenated hydrocarbons (dichloromethane, chloroform, trichloroethane, etc.), aliphatic alcohols (Methanol, ethanol, butanol, etc.), aliphatic polyhydric alcohols (ethylene glycol, glycerin, polyethylene glycol, etc.), aromatic alcohols (benzyl alcohol, phenethyl alcohol, etc.), esters (acetate ester, butyl acetate, etc.) , Ketones (acetone, methyl ethyl ketone, etc.), dimethyl sulfoxide, ethers (diethyl ether, tetrahydrofuran, etc.), a mixed solvent of two or more of the above solvents, and a mixed solvent of the above solvent and water. The usage-amount of a solvent is 1-200 weight part with respect to 1 weight part of pigment crystals, Preferably it is 10-100 weight part. The treatment temperature is in the range of 0 ° C to the boiling point of the solvent, preferably in the range of 10 to 60 ° C.
[0083]
In addition, grinding aids such as sodium chloride and sodium nitrate can be used during grinding. The amount of the grinding aid used is 0.5 to 20 times, preferably 1 to 10 times in weight ratio to the pigment crystals.
[0084]
In addition, the pigment crystal produced by a known method can be controlled by combining acid pasting or acid pasting with dry grinding or wet grinding as described above. The acid used for acid pasting is preferably sulfuric acid, more preferably 70 to 100% in concentration, and even more preferably 95 to 100%. The melting temperature is -20 to 100 ° C, preferably 0 to 60 ° C. The amount of sulfuric acid is 1 to 100 times, preferably 3 to 50 times, by weight ratio to the pigment crystals. As a solvent for depositing pigment crystals dissolved in sulfuric acid, water or a mixed solvent of water and an organic solvent is used in an arbitrary amount. The temperature for precipitation is not particularly limited, but it is preferably cooled with ice or the like in order to prevent heat generation.
[0085]
Chlorogallium phthalocyanine can be produced by the same method as described above, and is disclosed in detail in JP-A-5-98181. Hydroxygallium phthalocyanine can also be produced by the same method as described above except that the solvent treatment temperature is 0 to 150 ° C, preferably room temperature to 100 ° C. 279991.
[0086]
Oxytitanyl phthalocyanine also has a solvent usage of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 1 part by weight of pigment crystals, and a processing temperature of room temperature to 100 ° C., preferably 50. It can be produced by the same method as described above except that the temperature is -100 ° C, and is disclosed in detail in JP-A-4-189873 and JP-A-5-43813.
[0087]
The metal phthalocyanine can be subjected to a surface treatment for improving the stability of electric characteristics and preventing image quality defects. As the surface treatment agent, a coupling agent or the like can be used.
[0088]
As coupling agents used for the surface treatment, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxy Propyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like. Among these, silane coupling agents that are particularly preferably used include vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltri Examples include ethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.
[0089]
Zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, zirconium naphthenate, lauric acid Organic zirconium compounds such as zirconium, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like can also be used.
[0090]
Tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate Organic titanium compounds such as ethyl ester, titanium triethanolamate, polyhydroxytitanium stearate, aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) An organoaluminum compound such as can also be used.
[0091]
The charge generation layer 5 may be formed by vapor deposition of a charge generation material containing the metal phthalocyanine, or may be formed by dispersing the charge generation material in a binder resin. The binder resin can be selected from a wide range of insulating resins. It can also be selected from organic photoconductive polymers such as poly-N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene and polysilane. Preferred binder resins include polyvinyl acetal resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used singly or in combination of two or more. Among these, polyvinyl acetal resin is particularly preferably used.
[0092]
The charge generation layer 5 may further contain a charge generation material other than metal phthalocyanine as long as the absorbance satisfies the above conditions. Examples of such charge generating materials include metal-free phthalocyanine and azo pigments. The content of the charge generation material containing metal phthalocyanine is preferably 40% by weight or more, and more preferably 50% by weight or more based on the total amount of the charge generation material and the binder resin. In this case, the potential difference between the single exposure region and the multiple exposure region can be further suppressed.
[0093]
FIG. 10 is a graph showing an example of the correlation between the ratio between the charge generating material and the binder resin and the potential difference between the single exposure region and the multiple exposure region of the photoreceptor. In FIG. 10, the potential difference sharply decreases when the content of the charge generation material is about 25% by weight based on the total amount of the charge generation material and the binder resin, and no streak density unevenness occurs near 50% by weight. The potential difference is suppressed as much.
[0094]
Note that the reason why the effect of suppressing the potential difference is enhanced when the ratio between the charge generation material and the binder resin satisfies the above-described conditions is not necessarily clear, but the present inventors speculate as follows. That is, as the content ratio of the charge generation material in the charge generation layer increases, the distance that carriers generated by light irradiation move between the charge generation materials is shortened. As a result, carriers can be easily moved and the potential difference is suppressed.
[0095]
The charge generation layer 5 is formed using a charge generation layer forming coating solution containing a charge generation material and a binder resin, or using a vapor deposition method. In the case of vapor deposition, the charge generation layer 5 is composed only of a charge generation material.
[0096]
When the charge generation layer 5 is formed using a coating liquid for forming a charge generation layer, the content of the charge generation material in the charge generation layer 5 is 100 parts by weight with respect to the total amount of the charge generation material and the binder resin. The amount is preferably 40 to 80 parts by weight, more preferably 50 to 70 parts by weight.
[0097]
The charge generation layer 5 is formed by applying a charge generation layer forming coating solution in which a charge generation material and a binder resin are added to a predetermined solvent to a lower layer (undercoat layer, substrate, etc.) and drying. As a method for dispersing the charge generating substance in the coating solution, a usual method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used.
[0098]
In this dispersion, it is preferable to add particles, and the particle size is preferably 0.5 μm or less, more preferably 0.3 μm or less, and further preferably 0.15 μm or less.
[0099]
In order to obtain a good electrophotographic photosensitive member after the dispersion, a centrifugal separation process or a filtering process can be performed to remove foreign matters mixed during dispersion, coarse particles having poor dispersion, and the like.
[0100]
Centrifugation and filtering can be performed under any conditions that provide the desired electrophotographic photoreceptor characteristics, but care must be taken not to remove the necessary charge generating material. is there.
[0101]
As a coating method of the charge generation layer forming coating solution, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.
[0102]
Various additives may be added to the charge generation layer forming coating solution in order to improve electrical characteristics and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t-butyl Electron transporting materials such as diphenoquinone compounds such as diphenoquinone, electron transporting pigments such as polycyclic condensation systems and azo systems, zirconium chelate compounds, titanium Chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, there can be used a known material such as a silane coupling agent.
[0103]
As silane coupling agents, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ -Aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like.
[0104]
Zirconium chelate compounds include: zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthenic acid Zirconium, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.
[0105]
Titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium Examples include lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.
[0106]
Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).
[0107]
These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds.
[0108]
The film thickness of the charge generation layer 5 is set so as to satisfy the above-described absorbance condition, but is preferably 0.1 to 0.5 μm, and more preferably 0.1 to 0.3 μm.
[0109]
The charge transport layer 6 includes a charge transport material and a binder resin. Examples of the charge transport material include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenylpyrazoline, 1- [ Pyrazoline derivatives such as pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methylphenyl) amine, N, N′-bis ( Aromatic tertiary amino compounds such as 3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N′-di (p-tolyl) fluorenon-2-amine, N Aromatic tertiary diamino compounds such as N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1-biphenyl] -4,4'-diamine, 1,2,4-triazine derivatives such as-(4,4'-dimethylaminophenyl) -5,6-di- (4,4'-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde Hydrazone derivatives such as -1,1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl]-(1-naphthyl) phenylhydrazone, 2-phenyl-4-styrylquinazoline Quinazoline derivatives such as benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, and α-stilbene such as p- (2,2-diphenylvinyl) -N, N′-diphenylaniline Derivatives, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly Hole transport materials such as -N-vinylcarbazole and derivatives thereof; quinone compounds such as chloranil, bromoanil, anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5, Fluorenone compounds such as 7-tetranitro-9-fluorenone, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) ) -1,3,4-oxadiazole, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3, Electron transport materials such as diphenoquinone compounds such as 3 ′, 5,5′-tetra-t-butyldiphenoquinone; Polymers and the like having the main chain or side chain a group having a. These charge transport materials can be used alone or in combination of two or more.
[0110]
The binder resin used for the charge transport layer 6 is not particularly limited, but a resin that exhibits electrical insulation and can form a film is preferable. Examples of such binder resins include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, and vinylidene chloride. Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-carbazole , Polyvinyl butyral, polyvinyl formal, polysulfone, casein, gelatin, polyvinyl alcohol, ethyl cellulose, phenol resin, polyamide, carboxymethyl cellulose, vinylidene chloride Polymer waxes, polyurethanes, and the like. Among these, a polycarbonate resin, a polyester resin, a methacrylic resin, and an acrylic resin are preferable because they are excellent in compatibility with a charge transport material, solubility in a solvent, and strength. These binder resins can be used alone or in combination of two or more. The blending ratio (weight ratio) of the binder resin can be arbitrarily set, but from the viewpoint of suppressing the deterioration of the electrical characteristics and the film strength, the total amount of the binder resin and the charge transport material is preferably 100 parts by weight. 40 to 70 parts by weight.
[0111]
The charge transport layer 6 can be formed by applying a coating liquid obtained by adding a charge transport material and a binder resin to a predetermined solvent on the charge generation layer 5 and drying it. As a coating method, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used. As a solvent used for the coating solution, a common organic solvent such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene and the like can be used alone or in admixture of two or more.
[0112]
The film thickness of the charge transport layer 6 is preferably 5 to 50 μm, more preferably 10 to 35 μm.
[0113]
Furthermore, for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas, or light / heat generated in the electrophotographic apparatus, the electrophotographic photoreceptor contains an antioxidant / light stabilizer / heat stabilizer in each layer. Additives such as can be added.
[0114]
Antioxidants include hindered phenols, hindered amines, paraphenylenediamines, arylalkanes, hydroquinones, spirochromans, spiroidanones and their derivatives, organic sulfur compounds, and organic phosphorus compounds.
[0115]
Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxy Phenyl) -propionate, 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2-t-butyl-6- (3′-tert-butyl-5′-methyl-2′-) Hydroxybenzyl) -4-methylphenyl acrylate, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenol), 4,4′-thio-bis (3-methyl-6-tert-butylphenol), 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis [methylene-3- (3 ′, 5 ′,-di-t-butyl-4 ′ Hydroxyphenyl) propionate] -methane, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4 , 8,10-tetraoxaspiro [5,5] undecane and the like.
[0116]
Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl- N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.
[0117]
Examples of organic sulfur-based antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis. (Β-lauryl thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.
[0118]
Examples of the organic phosphorus-based antioxidant include trisnonylphenyl phosphite, triphenyl phosfeft, and tris (2,4-di-t-butylphenyl) phosphite.
[0119]
Organic sulfur-based and organic phosphorus-based antioxidants are said to be secondary antioxidants, and a synergistic effect can be obtained by using them together with primary antioxidants such as phenolic antioxidants and amine-based antioxidants. .
[0120]
Examples of the light stabilizer include benzophenone-based, benzotriazole-based, dithiocarbamate-based, and tetramethylpiperidine-based derivatives.
[0121]
Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and the like.
[0122]
Examples of the benzotriazole-based light stabilizer include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- [2′-hydroxy-3′-3 ″, 4 ″, 5 ″, 6 ″ -tetrahydro. Phthalimidomethyl) -5′-methylphenyl] benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3) '-T-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy -5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) -benzotriazole and the like. It is.
[0123]
Examples of other compounds include 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate and nickel dibutyldithiocarbamate.
[0124]
Further, at least one kind of electron accepting substance can be included for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like. Examples of the electron-accepting substance that can be used for the electrophotographic photosensitive member include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o- Examples include dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone, quinone, Cl, CN, NO₂Particularly preferred are benzene derivatives having electron-withdrawing substituents such as
[0125]
A small amount of silicone oil can be added to the coating solution as a leveling agent for improving the smoothness of the coating film.
[0126]
The electrophotographic photoreceptor can be provided with a protective layer 7 as necessary. By providing the protective layer 7, in the electrophotographic photosensitive member having a laminated structure, chemical change of the charge transport layer 6 during charging can be prevented, and the mechanical strength of the photosensitive layer 2 can be further improved. The protective layer 7 is constituted by containing a conductive material in an appropriate binder resin, for example.
[0127]
Examples of the conductive material used for the protective layer 7 include metallocene compounds such as N, N′-dimethylferrocene, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl, ] -4,4'-diamine and other aromatic amine compounds, molybdenum oxide, tungsten oxide, antimony oxide, tin oxide, titanium oxide, indium oxide, a solid solution carrier of tin oxide and antimony or antimony oxide, or a mixture thereof. Although what mixed these metal oxides in single particle, and what coat | covered are mentioned, It is not limited to these.
[0128]
The binder resin used for the protective layer 7 is polyamide resin, polyvinyl acetal resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, polyimide resin, polyamideimide resin. These can be used, and these can be used after being crosslinked. Furthermore, a siloxane-based resin having a charge transporting property and having a crosslinked structure can also be used as a protective layer. In the case of a cured siloxane resin film containing a charge transporting compound, any known material can be used as the charge transporting compound. For example, JP-A-10-95787, JP-A-10-251277, Examples thereof include, but are not limited to, compounds disclosed in JP-A-11-32716, JP-A-11-38656, and JP-A-11-236391. A specific example of the cured siloxane resin film containing a charge transporting compound can be represented by the general formula (I).
[0129]
F- [D-SiR¹ _3-a(OR²)_a]_b    (I)
[In General Formula (I), F represents an organic group derived from a photofunctional compound, D represents a divalent group, R¹Represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, and R²Represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, a represents an integer of 1 to 3, and b represents an integer of 1 to 4. ]
[0130]
In general formula (I), F is an organic group having photoelectric characteristics, more specifically, photocarrier transport characteristics, and the structure of a photofunctional compound conventionally known as a charge transport material can be used as it is. it can. Specific examples of the organic group represented by F include triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, and the like. Examples include a compound skeleton having a hole transporting property, and a compound skeleton having an electron transporting property such as a quinone compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, and an ethylene compound.
[0131]
In the general formula (I), -SiR¹ _3-a(OR²)_aAre groups for forming a three-dimensional Si—O—Si bond, that is, an inorganic vitreous network by cross-linking each other.
[0132]
In the general formula (I), the divalent group represented by D is for directly binding F for imparting charge transporting properties to a three-dimensional inorganic glassy network. In addition, the inorganic glassy network, which has firmness but is brittle, is imparted with appropriate flexibility and has an effect of improving the strength as a film. Specifically, -C_nH_2n-, -C_nH_2n-2-, -C_nH_2n-4A divalent hydrocarbon group represented by-(n is preferably 1 to 15), -COO-, -S-, -O-, -CH₂-C₆H₄-, -N = H-, -C₆H₄-C₆H₄-, And combinations thereof and those introduced with substituents.
[0133]
Preferable examples of the organic group represented by F include groups represented by the following general formula (II). When F is a group represented by the general formula (II), particularly excellent photoelectric characteristics and mechanical characteristics are exhibited.
[0134]
[Chemical 1]

[In the general formula (II), Ar³~ Ar⁶Each independently represents a substituted or unsubstituted aryl group, Ar⁷Represents a substituted or unsubstituted aryl group or arylene group, k represents 0 or 1, Ar³~ Ar⁷B of them are -D-SiR¹ _3-a(OR²)_aHaving a bond bonded to the group represented by ]
[0135]
Ar in the above general formula (II)³~ Ar⁶Is preferably any one of the following formulas (II-1) to (I-7).
[0136]
[Chemical formula 2]

[0137]
[Chemical Formula 3]

[0138]
[Formula 4]

[0139]
[Chemical formula 5]

[0140]
[Chemical 6]

[0141]
[Chemical 7]

-Ar-Z '_s-Ar-X_m    (II-7)
[0142]
[Wherein R³Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, or an unsubstituted phenyl group, or a group having 7 to 10 carbon atoms Represents one selected from the group consisting of aralkyl groups, R⁴~ R⁶Are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, or an unsubstituted phenyl group, or 7 to 10 carbon atoms. Represents an aralkyl group of formula (1) selected from the group consisting of a halogen atom, Ar represents a substituted or unsubstituted arylene group, and X represents -D-SiR in the general formula (I).¹ _3-a(OR²)_a, M and s represent 0 or 1, and t represents an integer of 1 to 3. ]
[0143]
Here, as Ar in Formula (II-7), what is represented by following formula (II-8) or (II-9) is preferable.
[0144]
[Chemical 8]

[0145]
[Chemical 9]

[0146]
[Wherein R⁷And R⁸Are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, or an unsubstituted phenyl group, and 7 to 10 carbon atoms. 1 type selected from the group which consists of an aralkyl group and a halogen atom is represented, and t represents the integer of 1-3. ]
[0147]
Moreover, as Z 'in Formula (II-7), what is represented by either of following formula (II-10)-(II-17) is preferable.
-(CH₂)_q-(II-10)
-(CH₂CH₂O)_r-(II-11)
[0148]
[Chemical Formula 10]

[0149]
Embedded image

[0150]
Embedded image

[0151]
Embedded image

[0152]
Embedded image

[0153]
Embedded image

[0154]
[Wherein R⁹And R¹⁰Are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, or an unsubstituted phenyl group, and 7 to 10 carbon atoms. 1 type selected from the group consisting of an aralkyl group and a halogen atom, W represents a divalent group, q and r each represent an integer of 1 to 10, and t represents an integer of 1 to 3, respectively. ]
[0155]
W in the above formulas (II-16) and (II-17) is preferably any one of divalent groups represented by the following (II-18) to (II-26). -CH₂-(II-18)
-C (CH₃)₂-(II-19)
-O- (II-20)
-S- (II-21)
-C (CF₃)₂-(II-22)
-Si (CH₃)₂-(II-23)
[0156]
Embedded image

[0157]
Embedded image

[0158]
Embedded image

[Wherein u represents an integer of 0 to 3]
[0159]
In general formula (II), Ar⁵Is Ar when k is 0¹~ Ar⁴And when k is 1, the aryl group is an arylene group in which a predetermined hydrogen atom is removed from the aryl group. As specific examples of the compound represented by the general formula (II), for example, compounds having compound numbers 1 to 274 described in Tables 1 to 55 in JP-A-2001-83728 can be used.
[0160]
The compound represented by general formula (I) may be used individually by 1 type, and may be used in combination of 2 or more type.
[0161]
In addition to the compound represented by the general formula (I), a compound having a group capable of binding to the compound represented by the general formula (I) may be used in combination for the purpose of further improving the mechanical strength of the cured film. Good. The group capable of binding to the compound represented by the general formula (I) means a group capable of binding to a silanol group generated when the compound represented by the general formula (I) is hydrolyzed. Specifically, -SiR¹ _3-a(OR²)_a, An epoxy group, an isocyanate group, a carboxyl group, a hydroxy group, a halogen atom, and the like. Of these, -SiR¹ _3-a(OR²)_aIn the case of having a group represented by general formula (I), an epoxy group, and an isocyanate group, the compound represented by the general formula (I) is preferable because it has higher mechanical strength. Furthermore, those having two or more of these groups in the molecule are preferable because the crosslinked structure of the cured film becomes three-dimensional and has higher mechanical strength.
[0162]
Among these, the most preferred compound is a compound represented by the general formula (III).
B-A_n      (III)
[In the general formula (III), A represents —SiR.¹ _3-a(OR²)_aAnd a group represented by R¹, R², A is R in the general formula (I)¹, R², A represents the same definition content as a. B represents an n-valent group composed of at least one selected from an n-valent hydrocarbon group and —NH—, and n represents an integer of 2 or more. ]
[0163]
In the general formula (III), when B is an n-valent hydrocarbon group or includes the hydrocarbon group, the hydrocarbon group is an alkyl group, an aryl group, an alkylaryl group, an arylalkyl group. Any of these may be used. Further, the alkyl group of the hydrocarbon group may be either linear or branched. Further, the hydrocarbon group may have a substituent.
[0164]
The compound represented by the general formula (III) is -SiR.¹ _3-a(OR²)_aIt is a compound which has a substituted silicon group which has a hydrolyzable group represented by these. The compound represented by the general formula (III) forms a Si—O—Si bond by the reaction with the compound represented by the general formula (I) or the reaction between the compounds represented by the general formula (III). To give a three-dimensional crosslinked cured film. When the compound represented by the general formula (III) and the compound represented by the general formula (I) are used in combination, the crosslinked structure of the cured film tends to be three-dimensional, and the cured film has an appropriate flexibility. As a result, stronger mechanical strength is obtained. As the compound represented by the general formula (III), compounds represented by the following formulas (III-1) to (III-5) are preferable.
[0165]
Embedded image

[0166]
Embedded image

[0167]
Embedded image

[0168]
Embedded image

[0169]
Embedded image

[Where T¹, T²Represents a divalent or trivalent hydrocarbon group which may be independently branched, and A represents a substituted silicon group having hydrolyzability described above. h, i, and j are each independently an integer of 1 to 3, but are selected so that the number of A in the molecule is 2 or more. ]
[0170]
Specific examples of the compounds represented by the following formulas (III-1) to (III-5) are shown in Table 1.
[0171]
[Table 1]

[0172]
The compound represented by the general formula (I) may be used alone, or for the purpose of adjusting the film formability and flexibility of the film, the compound represented by the general formula (III) and other cups You may mix and use a ring agent and a fluorine compound. As such a compound, various silane coupling agents and commercially available silicone hard coat agents can be used.
[0173]
As silane coupling agents, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, tetramethoxysilane, methyltrimethoxysilane, Dimethyldimethoxysilane and the like can be used. Commercially available hard coat agents include KP-85, X-40-9740, X-40-2239 (manufactured by Shin-Etsu Silicone), and AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning). Etc.) can be used. In addition, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- ( Heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoro Fluorine-containing compounds such as octyltriethoxysilane may be added. The silane coupling agent can be used in any amount, but the amount of the fluorine-containing compound is desirably 0.25 or less by weight with respect to the compound not containing fluorine. Beyond this, there may be a problem with the film formability of the crosslinked film.
[0174]
These coating solutions are prepared without solvent or, if necessary, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, diethyl ether and dioxane. Although it can be used, it preferably has a boiling point of 100 ° C. or less, and can be used by arbitrarily mixing. Further, the amount of the solvent can be arbitrarily set, but if it is too small, the compound represented by the general formula (I) is likely to be precipitated, and therefore preferably 0.5 to 1 part relative to 1 part of the compound represented by the general formula (I). It is used in a proportion of 30 parts by weight, more preferably 1 to 20 parts by weight. Although the reaction temperature and time vary depending on the type of raw material, it is usually 0-100 ° C, preferably 10-70 ° C, particularly preferably 150-50 ° C. Although there is no restriction | limiting in particular in reaction time, Since it will become easy to produce gelation when reaction time becomes long, it is preferable to carry out in 10 minutes to 100 hours.
[0175]
In order to adjust the coating solution, the following catalyst can be used as a solid catalyst insoluble in the system, and hydrolysis can be performed in advance.
Cation exchange resin: Amberlite 15, Amberlite 200C, Amberlist 15 (above, manufactured by Rohm and Haas); Dowex MWC-1-H, Dowex 88, Dowex HCR-W2 (above, Dow Chemical Company); Lebatit SPC-108, Lebatit SPC-118 (above, Bayer); Diaion RCP-150H (Mitsubishi Kasei); Sumikaion KC-470, Duolite C26-C, Duolite C-433 Duolite-464 (manufactured by Sumitomo Chemical Co., Ltd.); Nafion-H (manufactured by DuPont) and the like.
Anion exchange resin: Amberlite IRA-400, Amberlite IRA-45 (above, manufactured by Rohm and Haas) and the like.
Inorganic solid having a group containing a protonic acid group bonded to the surface: Zr (O₃PCH₂CH₂SO₃H)₂, Th (O₃PCH₂CH₂COOH)₂etc.
Polyorganosiloxane containing a protonic acid group: polyorganosiloxane having a sulfonic acid group.
[0176]
Heteropoly acid: cobalt tungstic acid, phosphomolybdic acid, etc.
Isopolyacid: niobic acid, tantalum acid, molybdic acid, etc.
Unitary metal oxides: silica gel, alumina, chromia, zirconia, CaO, MgO and the like.
Composite metal oxides: silica-alumina, silica-magnesia, silica-zirconia, zeolites and the like.
Clay minerals: acid clay, activated clay, montmorillonite, kaolinite, etc.
Metal sulfate: LiSO₄, MgSO₄etc.
Metal phosphate: zirconia phosphate, lanthanum phosphate, etc.
Metal nitrate: LiNO₃, Mn (NO₃)₂etc.
Inorganic solid in which a group containing an amino group is bonded to the surface: a solid obtained by reacting aminopropyltriethoxysilane on silica gel or the like.
Polyorganosiloxane containing amino groups: amino-modified silicone resin and the like.
[0177]
Of these catalysts, at least one kind is used to cause the hydrolysis condensation reaction. These catalysts can be installed in a fixed bed and the reaction can be carried out in a flow system or batchwise. Although the usage-amount of a catalyst is not specifically limited, 0.1-20 wt% is preferable with respect to the total amount of the material containing a hydrolysable silicon substituent.
[0178]
The amount of water added during the hydrolytic condensation is not particularly limited. However, since it affects the storage stability of the product and further the suppression of gelation when subjected to polymerization, it is preferable to add water of the compound represented by the general formula (I). It is preferably used in a proportion of 30 to 500%, more preferably 50 to 300%, based on the theoretical amount necessary to hydrolyze all the degradable groups. When the amount of water is more than 500%, the storage stability of the product tends to deteriorate or the product tends to precipitate. On the other hand, when the amount of water is less than 30%, unreacted compounds increase, and there is a tendency to cause phase separation or decrease in strength at the time of applying and curing the coating liquid.
[0179]
Further, examples of the curing catalyst include the following. Protic acids such as hydrochloric acid, acetic acid, phosphoric acid and sulfuric acid, bases such as ammonia and triethylamine, organotin compounds such as dibutyltin diacetate, dibutyltin dioctoate and stannous oxalate, tetra-n-butyl titanate, tetraisopropyl titanate Organic titanium compounds such as aluminum tributoxide, aluminum triacetylacetonate, and the like, and iron salts, manganese salts, cobalt salts, zinc salts, zirconium salts and the like of organic carboxylic acids. Among them, a metal compound is preferable from the viewpoint of storage stability, and further, metal acetylacetonate or acetylacetate is preferable, and aluminum triacetylacetonate is particularly preferable.
[0180]
The amount of the curing catalyst used can be arbitrarily set, but is preferably 0.1 to 20 wt% with respect to the total amount of the material containing hydrolyzable silicon substituents in terms of storage stability, characteristics, strength, and the like. 3-10 wt% is more preferable. The curing temperature can be arbitrarily set, but is set to 60 ° C. or higher, more preferably 80 ° C. or higher in order to obtain a desired strength. Although hardening time can be arbitrarily set as needed, 10 minutes-5 hours are preferable. It is also effective to stabilize the characteristics after the curing reaction by maintaining a high humidity state. Further, depending on the application, it can be hydrophobized by surface treatment with hexamethyldisilazane, trimethylchlorosilane, or the like.
[0181]
An antioxidant is preferably added to the surface cross-linked cured film of the electrophotographic photosensitive member for the purpose of preventing deterioration due to an oxidizing gas such as ozone generated by a charger. When the mechanical strength of the surface of the photoconductor is increased and the photoconductor has a long life, the photoconductor is in contact with an oxidizing gas for a long time, and therefore, stronger oxidation resistance is required than the conventional one. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by weight or less, and more preferably 10% by weight or less.
[0182]
Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide), 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) ), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 2,5-di-tert-amylhydroquinone, 2-tert-butyl-6- (3-butyl-2) Hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol), and the like.
[0183]
Also, a resin that dissolves in alcohol can be added for the purposes of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like. Examples of resins soluble in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral is modified with formal or acetoacetal (for example, Sekisui Chemical Co., Ltd.) S-Rec B, K, etc.), polyamide resin, cellulose resin, phenol resin and the like. In particular, polyvinyl acetal resin is preferable in terms of electrical characteristics. The molecular weight of the resin is preferably 2000-100000, more preferably 5000-50000. If the molecular weight is less than 2,000, the desired effect tends to be lost, and if it exceeds 100,000, the solubility tends to be low and the amount added is limited, or the film formation tends to be poor during application. The addition amount of the resin is preferably 1 to 40% by weight, more preferably 1 to 30% by weight, and most preferably 5 to 20% by weight. If the amount is less than 1% by weight, the desired effect tends to be difficult to obtain. On the other hand, if the amount exceeds 40% by weight, image blurring tends to occur under high temperature and high humidity.
[0184]
Furthermore, various fine particles can be added in order to improve the antifouling substance adhesion and lubricity on the surface of the electrophotographic photosensitive member. They can be used alone or in combination of two or more. Examples of the fine particles include silicon-containing fine particles. Silicon-containing fine particles are fine particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone fine particles. The colloidal silica used as the silicon-containing fine particles is selected from acidic or alkaline aqueous dispersions having an average particle diameter of 1 to 100 nm, preferably 10 to 30 nm, or those dispersed in organic solvents such as alcohols, ketones and esters. A commercially available product can be used. The solid content of colloidal silica in the outermost surface layer is not particularly limited, but is 0.1 to 50 based on the total solid content of the outermost surface layer in terms of film forming properties, electrical characteristics, and strength. It is used in the range of wt%, more preferably in the range of 0.1-30 wt%.
[0185]
The silicone fine particles used as the silicon-containing fine particles are spherical and have an average particle diameter of 1 to 500 nm, preferably selected from silicone resin particles, silicone rubber particles, and silicone surface-treated silica particles having a particle size of 10 to 100 nm. Can be used. Silicone fine particles are small particles that are chemically inert and excellent in dispersibility in resin, and since the content required to obtain sufficient characteristics is low, the electron does not hinder the crosslinking reaction, The surface properties of the photographic photoreceptor can be improved. In other words, it is possible to improve the lubricity and water repellency of the surface of the electrophotographic photosensitive member while being uniformly incorporated into a strong cross-linked structure, and to maintain good wear resistance and adherence to contaminants over a long period of time. it can. The content of the silicone fine particles in the outermost surface layer in the electrophotographic photosensitive member is in the range of 0.1 to 30% by weight, preferably 0.5 to 10% by weight, based on the total solid content of the outermost surface layer. It is a range.
[0186]
Other fine particles include fluorine fine particles such as ethylene tetrafluoride, trifluoride ethylene, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and the 8th Polymer Materials Forum Lecture Proceedings p89. ZnO-Al, a fine particle made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group₂O₃, SnO₂-Sb₂O₃, In₂O₃-SnO₂ZnO-TiO₂ZnO-TiO₂MgO-Al₂O₃, FeO-TiO₂TiO₂, SnO₂, In₂O₃And semiconductive metal oxides such as ZnO and MgO.
[0187]
For the same purpose, an oil such as silicone oil can be added. Silicone oils include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, and mercapto-modified polysiloxane. Reactive silicone oils such as siloxane and phenol-modified polysiloxane, cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, 1,3,5- Trimethyl-1,3,5-triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclo Cyclosiloxane, cyclic methylphenylcyclosiloxanes such as 1,3,5,7,9-pentamethyl-1,3,5,7,9-pentaphenylcyclopentasiloxane, and cyclic phenylcyclosiloxanes such as hexaphenylcyclotrisiloxane , Fluorine-containing cyclosiloxanes such as 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane, hydrosilyl group-containing cyclosiloxanes such as methylhydrosiloxane mixture, pentamethylcyclopentasiloxane, and phenylhydrocyclosiloxane And cyclic siloxanes such as vinyl group-containing cyclosiloxanes such as pentavinylpentamethylcyclopentasiloxane.
[0188]
In addition, additives such as plasticizers, surface modifiers, antioxidants, and photodegradation inhibitors can also be used. Examples of the plasticizer include biphenyl, biphenyl chloride, terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphate, methyl naphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, and various fluorohydrocarbons.
[0189]
A siloxane-based resin having a charge transporting property and having a cross-linked structure has excellent mechanical strength and sufficient photoelectric characteristics. Therefore, it can be used as it is as a charge transport layer of a multilayer photoreceptor. In that case, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used. However, when a required film thickness cannot be obtained by a single application, the necessary film thickness can be obtained by applying a plurality of times. When performing multiple times of repeated application, the heat treatment may be performed every time of application, or after multiple times of repeated application.
[0190]
Next, the single layer type photosensitive layer will be described. The single-layer type photosensitive layer includes a charge generation material, a charge transport material, and a binder resin. This single-layer type photosensitive layer has an absorbance A represented by the above formula (1).₁Or absorbance A represented by the above formula (2)₂Is 0.5 or more. Such absorbance can be measured by the same method as that for the charge generation layer 5.
[0191]
As the charge generation material, charge transport material and binder resin, the same charge generation material, charge transport material and binder resin as those used for the charge generation layer 5 and the charge transport layer 6 can be used. . The content of the charge generation material in the single-layer type photosensitive layer is preferably 20% by weight or more, more preferably 30% by weight or more, based on the total amount of the charge generation material and the binder resin. The content of the charge transport material is preferably 5 to 50% by weight based on the total amount of the constituent materials of the photosensitive layer. The solvent and coating method used for coating can be performed by the same method as that for the charge generation layer 5.
[0192]
The thickness of the single-layer type photosensitive layer is not particularly limited as long as it satisfies the above absorbance condition, but is preferably 5 to 50 μm, and more preferably 10 to 40 μm.
[0193]
As described above, in the first embodiment, by using the electrophotographic photosensitive member 12 including the first or second metal phthalocyanine-containing layer whose absorbance satisfies the specific condition, the cavity volume is small and the aperture is used. Even when the multi-beam type exposure apparatus 14 with a small amount of light emission is used, it is possible to realize both speeding up of the image forming process and improvement of image quality.
[0194]
Further, the image forming apparatus of the first embodiment can be used together with a one-component or two-component regular developer or a reversal developer, and a developer manufactured by a pulverization method or a polymerization method (predetermined It is also preferable to use a toner having an average shape index. Also, excellent electrophotographic characteristics and image quality characteristics can be obtained by a contact charging method using a charging roller or a charging brush and a transfer method using an intermediate transfer member.
[0195]
Next, a second embodiment of the present invention will be described. FIG. 11 is a schematic configuration diagram showing a second embodiment of the image forming apparatus of the present invention. An image forming apparatus 200 shown in FIG. 11 is an intermediate transfer type image forming apparatus. In the housing 400, four electrophotographic photoreceptors 401a to 401d (for example, the electrophotographic photoreceptor 401a is yellow and the electrophotographic photoreceptor 401b is magenta). The electrophotographic photosensitive member 401c can form an image of cyan and the electrophotographic photosensitive member 401d can form a black color) are arranged in parallel along the intermediate transfer belt 409. Here, each of the electrophotographic photoreceptors 401a to 401d mounted on the image forming apparatus 200 includes a photosensitive layer on the outer peripheral surface of a drum-shaped conductive substrate, and a charge generation layer (single layer type) in the photosensitive layer. In this case, the absorbance of the photosensitive layer) satisfies a specific condition.
[0196]
Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toner of four colors of black, yellow, magenta and cyan accommodated in the toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are respectively intermediate transfer belts. 409 is in contact with the electrophotographic photoreceptors 401a to 401d.
[0197]
Further, an exposure device 403 using a surface emitting laser array as a light source is disposed at a predetermined position in the housing 400, and the electrophotographic photoreceptors 401a to 401d after charging the laser light emitted from the exposure device 403 are arranged. It is possible to irradiate the surface. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.
[0198]
The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409. The intermediate transfer belt 409 passing between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed in the vicinity of the drive roll 406 and then repeatedly used for the next image forming process. Is done.
[0199]
Further, a tray (transfer object tray) 411 is provided at a predetermined position in the housing 400, and the transfer object 500 such as paper in the tray 411 is transferred by the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.
[0200]
In the above description, the case where the intermediate transfer belt 409 is used as the intermediate transfer member has been described. However, the intermediate transfer member may have a belt shape like the intermediate transfer belt 409 or a drum shape. Also good.
[0201]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.
[0202]
(Example 1)
100 parts by weight of zinc oxide (average particle size 70 nm: prototype manufactured by Teika) and 500 parts by weight of toluene are mixed and stirred, and 1.5 parts by weight of a silane coupling agent (KBM603: manufactured by Shin-Etsu Chemical Co., Ltd.) is further added. Stir for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours.
[0203]
60 parts by weight of zinc oxide subjected to the above surface treatment, 15 parts by weight of blocked isocyanate (Sumijoule 3175: manufactured by Sumitomo Bayern Urethane Co., Ltd.) as a curing agent, and 15 parts by weight of butyral resin (BM-1: manufactured by Sekisui Chemical Co., Ltd.) Was dissolved in 85 parts by weight of methyl ethyl ketone. 38 parts by weight of the solution and 25 parts by weight of methyl ethyl ketone were mixed and dispersed in a sand mill for 2 hours using 1 mmφ glass beads to obtain a dispersion.
[0204]
As a catalyst, 0.005 part by weight of dioctyltin dilaurate was added to the obtained dispersion to obtain a coating solution for forming an undercoat layer. This coating solution was applied onto an aluminum substrate having a diameter of 30 mm, a length of 340 mm, and a thickness of 1 mm by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to obtain an undercoat layer having a thickness of 20 μm.
[0205]
4 parts by weight of a hydroxygallium phthalocyanine pigment having diffraction peaks at positions of at least 7.6 ° and 28.2 ° in a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using CuKα rays as a charge generating material, A mixture of 6 parts by weight of vinyl chloride / vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin and 300 parts by weight of n-butyl alcohol was used for 4 hours in a sand mill using 1 mmφ glass beads. Distributed. The obtained dispersion was dip-coated on the undercoat layer as a charge generation layer forming coating solution and dried to form a charge generation layer having an absorbance of 0.5 with a semiconductor laser (wavelength: 780 nm). The thickness of this charge generation layer was 0.2 μm. Table 2 shows data relating to the charge generation layer.
[0206]
When measuring the absorbance of the charge generation layer, first, a 0.2 μm charge generation layer was formed on the transparent substrate (glass plate) using the same charge generation layer forming coating solution as described above. Next, the transmitted light amount T of the laminate composed of the transparent substrate and the charge generation layer using a spectrophotometer U-2000 (manufactured by HITACHI)._b(= T) is measured, the transmitted light amount T and the incident light amount T₀Was applied to the above formula (1) to determine the absorbance. In addition, the transparent base material had little absorption of light with a wavelength of 780 nm.
[0207]
Next, to a mixture of 4 parts by weight of a compound represented by the following formula (IV) as a charge transport material and 6 parts by weight of a bisphenol Z-type polycarbonate resin (molecular weight 40,000) as a binder resin, 80 parts by weight of tetrahydrofuran and 2,6 -0.2 part by weight of di-t-butyl-4-methylphenol was added and dissolved. This solution was applied onto the charge generation layer and dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 28 μm, thereby producing an electrophotographic photoreceptor.
[0208]
Embedded image

[0209]
Using an electrophotographic photosensitive member having three layers of an undercoat layer, a charge generation layer, and a charge transport layer, the thus obtained photosensitive layer is an image forming apparatus (manufactured by Fuji Xerox Co., Ltd., A DocuCentre 500 speed-up modified machine (black and white 110 Print / min · A4)) was produced. As the exposure apparatus, a surface emitting laser array having light emitting points arranged in a two-dimensional array of 6 × 6, a laser beam number of 32, and a scanning line number of 2400 dpi was used. In addition, toner having an average shape factor SF1 of 118 was used.
[0210]
(Example 2)
In Example 1, the amount of charge generation material used was changed to 5 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 0.7 with a semiconductor laser (wavelength: 780 nm). A photoconductor was prepared in the same manner as in Example 1 except that. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0211]
(Example 3)
In Example 1, the amount of charge generation material used was changed to 6 parts by weight and the amount of binder resin used was changed to 4 parts by weight to form a charge generation layer having an absorbance of 1.0 with a semiconductor laser (wavelength: 780 nm). A photoconductor was prepared in the same manner as in Example 1 except that. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0212]
Example 4
In Example 1, the amount of charge generation material used was changed to 6 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 0.5 with a semiconductor laser (wavelength: 780 nm). A photoconductor was prepared in the same manner as in Example 1 except for the above. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0213]
(Example 5)
In Example 1, at least 7.4 °, 16.6 °, 25.5 °, 28.3 in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using the CuKα ray as the charge generation material. A photoconductor was prepared in the same manner as in Example 1 except that a chlorogallium phthalocyanine pigment having a diffraction peak at a position of ° and a charge generation layer having an absorbance of 0.5 with a semiconductor laser (wavelength: 780 nm) were formed. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0214]
(Example 6)
In Example 5, the amount of charge generation material used was changed to 5 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 0.7 with a semiconductor laser (wavelength: 780 nm). A photoreceptor was prepared in the same manner as in Example 5 except for the above. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0215]
(Example 7)
In Example 5, the amount of charge generation material used was changed to 6 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 1.0 with a semiconductor laser (wavelength: 780 nm). A photoreceptor was prepared in the same manner as in Example 5 except for the above. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0216]
(Example 8)
In Example 5, the amount of charge generation material used was changed to 6 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 0.5 with a semiconductor laser (wavelength: 780 nm). A photoreceptor was prepared in the same manner as in Example 5 except for the above. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0217]
Example 9
In Example 1, the charge generating material is an oxytitanyl phthalocyanine pigment having a diffraction peak at a position of at least 27.3 ° in the Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using CuKα rays, and a semiconductor. A photoconductor was prepared in the same manner as in Example 1 except that a charge generation layer having an absorbance of 0.5 with a laser (wavelength: 780 nm) was formed. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0218]
(Example 10)
In Example 9, the amount of charge generation material used was changed to 5 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 0.7 with a semiconductor laser (wavelength: 780 nm). A photoreceptor was prepared in the same manner as Example 9 except for the above. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0219]
Example 11
In Example 9, the amount of charge generation material used was changed to 6 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 1.0 with a semiconductor laser (wavelength: 780 nm). A photoreceptor was prepared in the same manner as in Example 9 except that. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0220]
Example 12
In Example 9, the amount of charge generation material used was changed to 6 parts by weight and the amount of binder resin used was changed to 5 parts by weight to form a charge generation layer having an absorbance of 0.5 with a semiconductor laser (wavelength: 780 nm). A photoreceptor was prepared in the same manner as in Example 9 except that. Each data related to the charge generation layer is shown in Table 2 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0221]
(Comparative Example 1)
Example 1 is different from Example 1 except that the charge generation material is changed to 3 parts by weight and the binder resin is 7 parts by weight, and a charge generation layer having an absorbance of 0.4 with a semiconductor laser (wavelength: 780 nm) is formed. A photoconductor was produced in the same manner. Table 3 shows data relating to the charge generation layer. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0222]
(Comparative Example 2)
In Example 1, the thickness of the charge generation layer was changed, and a photoconductor was produced in the same manner as in Example 1 except that a charge generation layer having an absorbance of 0.4 with a semiconductor laser (wavelength: 780 nm) was formed. did. Table 3 shows data relating to the charge generation layer. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0223]
(Comparative Example 3)
Example 5 was the same as Example 5 except that the charge generation material was changed to 3 parts by weight and the binder resin was 7 parts by weight, and a charge generation layer having an absorbance of 0.4 with a semiconductor laser (wavelength: 780 nm) was formed. Thus, a photoreceptor was produced. Each data regarding the charge generation layer is shown in Table 3 as in Example 1. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0224]
(Comparative Example 4)
A photoconductor was prepared in the same manner as in Example 5 except that in Example 5, the thickness of the charge generation layer was changed and a charge generation layer having an absorbance of 0.4 with a semiconductor laser (wavelength: 780 nm) was formed. Table 3 shows data relating to the charge generation layer. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0225]
(Comparative Example 5)
Example 9 is the same as Example 9 except that the charge generation material is changed to 3 parts by weight and the binder resin is 7 parts by weight, and a charge generation layer having an absorbance of 0.4 with a semiconductor laser (wavelength: 780 nm) is formed. Thus, a photoreceptor was produced. Table 3 shows data relating to the charge generation layer. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0226]
(Comparative Example 6)
A photoconductor was prepared in the same manner as in Example 9 except that the charge generation layer was changed in thickness and a charge generation layer having an absorbance of 0.4 with a semiconductor laser (wavelength: 780 nm) was formed. Table 3 shows data relating to the charge generation layer. Further, an image forming apparatus similar to that of Example 1 was produced using the electrophotographic photoreceptor.
[0227]
[Evaluation of image quality]
Using the image forming apparatuses of Examples 1 to 13 and Comparative Examples 1 to 6, printing tests were performed at a process speed of 120 mm / s and at normal temperature and humidity (20 ° C., 40% RH). Image quality is based on the following standards:
A: The occurrence of uneven stripe density is not visible,
B: The occurrence of uneven stripe density is not visible or slight,
C: The occurrence of uneven stripe density is significant,
Was evaluated visually. The obtained results are shown in Tables 2 and 3. As the paper at this time, Fuji Xerox Co., Ltd. PPC paper (L, A4) was used.
[0228]
[Table 2]

[0229]
[Table 3]

[0230]
【The invention's effect】
As described above, according to the image forming apparatus of the present invention, even when a surface emitting laser array capable of increasing the number of lasers is used, the occurrence of streaky density unevenness can be sufficiently suppressed, and the image Both an increase in the formation speed and an improvement in image quality can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a first embodiment of an image forming apparatus of the present invention.
FIG. 2 is a schematic block diagram that shows an example of an exposure apparatus (optical scanning apparatus) according to the present invention.
FIG. 3 is a plan view showing a laser array in which light emitting points are two-dimensionally arranged.
FIG. 4 is a schematic configuration diagram showing an example of a control device according to the present invention.
FIG. 5 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member according to the present invention.
FIG. 6 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member according to the present invention.
FIG. 7 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member according to the present invention.
FIG. 8 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member according to the present invention.
FIG. 9 is a graph showing an example of the correlation between the absorbance of the charge generation layer of the function-separated type photoconductor and the potential difference between the single exposure region and the multiple exposure region of the photoconductor.
FIG. 10 is a graph showing an example of the correlation between the ratio between the charge generation material and the binder resin in the charge generation layer of the function-separated type photoconductor and the potential difference between the single exposure region and the multiple exposure region of the photoconductor. is there.
FIG. 11 is a schematic configuration diagram illustrating a second embodiment of the image forming apparatus according to the invention.
FIG. 12 is a graph showing a distribution of exposure energy along the moving direction (sub-scanning direction) of the electrophotographic photosensitive member.
FIG. 13 is a schematic diagram showing density unevenness between a single exposure region and a multiple exposure region.
[Explanation of symbols]
2 ... conductive support, 3 ... photosensitive layer, 4 ... undercoat layer, 5 ... charge generation layer, 6 ... charge transport layer, 7 ... protective layer, 100 ... image forming apparatus, 12 ... electrophotographic photoreceptor, 14 ... Charger, 16 ... exposure device, 18 ... developing device, 24 ... intermediate transfer belt, 32, 42 ... transfer device, 44 ... fixing device, 50 ... surface emitting laser array, 51 ... light emitting point, 52 ... collimating lens, 54 ... Half mirror, 56 ... lens, 58 ... light quantity sensor, 60 ... aperture, 62 ... cylinder lens, 64 ... folding mirror, 66 ... rotating polygon mirror, 68, 70 ... Fθ lens, 72, 74 ... cylinder mirror, 76 ... pickup mirror 78 ... Beam position detection sensor, 80 ... Control unit, 82 ... Storage unit, 84 ... Modulation signal generation unit, 88 ... Drive amount control unit, 92 ... Level change unit, 94 ... Light quantity difference setting unit, 200 ... Image Forming device 400 ... housing 402a-402d charging roll 403 exposure device 404a-404d developing device 405a-405d toner cartridge 406 driving roll 407 tension roll 408 backup roll 409 ... Intermediate transfer belt, 410a to 410d ... Primary transfer roll, 411 ... Tray (transfer target tray), 412 ... Transfer roll, 413 ... Secondary transfer roll, 414 ... Fixing roll, 415a-415d ... Cleaning blade, 416 ... Cleaning blade, 500 ... Transfer object.

Claims (7)

An electrophotographic photosensitive member having a conductive substrate and a photosensitive layer formed on the substrate, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image An exposure device for developing, a developing device for developing the electrostatic latent image with toner to form a toner image, and a transfer device for transferring the toner image from the electrophotographic photosensitive member to a transfer medium,
The exposure apparatus includes a surface emitting laser array having three or more light emitting elements as an exposure light source, and employs a multi-beam method in which a plurality of light beams are scanned on the electrophotographic photosensitive member to form the electrostatic latent image. Having a configuration to
The photosensitive layer, the image forming apparatus characterized by absorbance A ₁ represented by and the following formula wherein the metal phthalocyanine (1) has a first metal phthalocyanine-containing layer is 0.5 or more.
A ₁ = log ₁₀ (T ₀ / T) (1)
Wherein (1), T ₀ and T is the amount of incident light and transmitted light amount of each light beam. ] An electrophotographic photosensitive member having a conductive substrate and a photosensitive layer formed on the substrate, a charging device for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image An exposure device for developing, a developing device for developing the electrostatic latent image with toner to form a toner image, and a transfer device for transferring the toner image from the electrophotographic photosensitive member to a transfer medium,
The exposure apparatus includes a surface emitting laser array having three or more light emitting elements as an exposure light source, and employs a multi-beam method in which a plurality of light beams are scanned on the electrophotographic photosensitive member to form the electrostatic latent image. Having a configuration to
The photosensitive layer, the image forming apparatus characterized by absorbance A ₂ represented by and the following formula wherein the metal phthalocyanine (2) has a second metal phthalocyanine-containing layer is 0.5 or more.
A ₂ = (1/2) · log ₁₀ (R ₀ / R) (2)
[In the formula (2), R represents a light beam from the side of the second metal phthalocyanine-containing layer to the first irradiated object except the layer farther from the substrate than the second metal phthalocyanine-containing layer from the photoreceptor. The amount of reflected light when irradiated is represented by R ₀ from the side where the second metal phthalocyanine-containing layer is provided on the second object to be irradiated except the second metal phthalocyanine-containing layer from the first object to be irradiated. It represents the amount of reflected light when irradiated with a light beam. ] In the first metal phthalocyanine-containing layer or the second metal phthalocyanine-containing layer, the content of the charge generating material containing the metal phthalocyanine is 40% by weight or more based on the total amount of the charge generating material and the binder resin. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 4. The film thickness of the first metal phthalocyanine-containing layer or the second metal phthalocyanine-containing layer is 0.1 to 0.5 μm, according to claim 1. Image forming apparatus. The image forming apparatus according to claim 1, wherein the metal phthalocyanine is at least one selected from hydroxygallium phthalocyanine, chlorogallium phthalocyanine, and oxytitanyl phthalocyanine. The image forming apparatus according to claim 1, wherein the resolution is 1200 dpi or more and the process speed is 100 mm / s or more. The image forming apparatus according to claim 1, wherein an average value of the shape factor of the toner is 115 to 140.

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