JP3759400B2

JP3759400B2 - Photoconductor deterioration acceleration test equipment

Info

Publication number: JP3759400B2
Application number: JP2000343392A
Authority: JP
Inventors: 紀保齋藤; 潔増田
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2000-11-10
Filing date: 2000-11-10
Publication date: 2006-03-22
Anticipated expiration: 2020-11-10
Also published as: JP2002149005A

Description

【０００１】
【発明の属する技術分野】
本発明は、電子写真方式で用いる感光体の特性判断方法および診断装置に関する。
【０００２】
【従来の技術】
電子写真プロセスで使用される感光体は繰り返し使用されるため、繰り返し使用による感光体の寿命を予測するための試験・評価方法は極めて重要な技術である。この寿命試験方法としては、▲１▼電子写真プロセスを実行する複写機、あるいはプリンタを使って繰り返し紙に印字させ、出力された画像の品質で感光体の寿命を判断したり、繰り返し印字テスト中の、帯電電位、露光後電位を計測し、これら電位の変動で寿命を予測することが行われる、この方法は感光体が搭載される実施機で行われることが普通であるので，確実な寿命予測ができる一方、実施機が完成するまで寿命試験ができない、試験に多大な時間が必要となる。例えば、Ａ４サイズのプリントアウト能力が１０枚／分とすると、１００，０００枚プリントアウトするのに１０，０００分…１日１０時間試験して１６．６日かかる計算となる。
【０００３】
このため、別の方法として、▲２▼感光体を高速で回転させた状態（１，０００〜２，０００ｒ．ｐ．ｍ）で感光体の周囲に配置された帯電器、露光装置で帯電、露光を繰り返し、寿命を予測する方法がある。この方法は、さらに二つの試験方法に分かれる。その一つは、帯電器の出力と露光装置の光量を予め決めた条件で固定し、決められた時間だけ試験を行い、その後、感光体の特性を評価する測定を行い、劣化状態を判定するものである。二つめの方法は、試験中の感光体露光後電位Ｖと感光体を通して流れる通過電流Ｉを計測し、この二つが常に決められたレベルにあるように、帯電器の出力と露光装置の光量を調整しながら行う方法である。
【０００４】
▲２▼の二つの方法で重要な点は、試験中に感光体に流れた通過電流を計測し、これを電荷量（単位面積当りの値）Ｑに変換し、一方、Ａ４サイズ１枚を実施機でプリントアウトする時、感光体のサイズは、Ａ４サイズ１枚が感光体上を重なることなく印字されるサイズであるとすると、感光体を流れる通過電流が、感光体の静電容量をＣ（単位面積当りの値）、帯電電位Ｖとして、「Ｃ・Ｖ」で求まることから、「Ｑ／Ｃ・Ｖ」とすることで寿命試験時間を実施機のプリント枚数に対応させることができる点である。
【０００５】
もう一つ重要な点は、この試験が加速寿命試験になっていることである。具体的に示すと、感光体に５．６μＡ／１９．６cm²の試料通過電流を流し、２０Ｈｒ試験すると（１日１０時間の試験とすると２日間）、５．６／１９．６×１０^-6×２０×６０×６０＝０．０２０５７（Ｃ／cm²）の電荷が感光体を通過したことになる。そして、Ａ４用紙縦送りで印字する場合を想定すると、感光体の静電容量を１００（ｐＦ／cm²）、帯電電位−７００（Ｖ）、除電後も含めた露光後電位を０（Ｖ）とすると、１００×１０^-12×７００＝７×１０^-6（Ｃ／cm²）がＡ４サイズ１枚をプリントアウトする時に感光体を通過する電荷であるので、０．０２０５７／（７×１０^-6）≒２９４，０００（枚）をプリントアウトしたことになり、寿命試験を大幅に加速して行うこととなる。このため、▲２▼の方法で寿命試験が行われることが多い。
【０００６】
しかしながら、前述の具体的な計算で分かるように、試験中に感光体を通過する電流が一定であれば、プリントアウト何枚相当の試験を行ったのか、計算がしやすい。そのため、試験は通過電流を一定にして実施する方法が一般的に採られる。（その本質は通過電荷量を知ることにある。）また、感光体によっては、帯電電位がどのレベルにあるかによって寿命試験の結果が異なることがあり、帯電電位も一定にして試験を行うことが要求される。
【０００７】
そこで、帯電電位および通過電流を一定にするために、帯電器の高圧電源出力調整、および露光装置の光量調整を行うシステムが必要となり、従来の寿命試験装置が構築された。
【０００８】
この種の装置として関連するものには、特願平５−１９７３号がある。
【０００９】
【発明が解決しようとする課題】
しかしながら、前述のシステムでは、二つの測定量、表面電位Ｘ、通過電流Ｙと、二つの操作量、帯電器高圧電源の出力制御値Ａ、除電露光ランプ光量の出力制御値Ｂの関係は、Ａが増加するとＸ、Ｙは増加し、Ａが減少するとＸ、Ｙも減少し、Ｂが増加すると、Ｘは減少して、Ｙは増加し、Ｂが減少すると、Ｘは増加して、Ｙは減少するというものであり、仮にＸが目標値からはずれ、これを目標範囲に入れようとＡまたはＢを操作すると、もう１つの測定量Ｙが変化してしまい、Ｙにとっては外乱が作用することになり、これを目標範囲に維持しようとＡまたはＢを操作すると、今度はＸが変化するという状態になってしまい、非常に複雑な制御を行わなければならなかった。また、前記システムでは、劣化加速試験中に感光体表面電位・通過電流の瞬間的なバラツキがあった場合でも、それらが瞬間的な誤差として通過電荷量算出に反映されない。
【００１０】
そこで、本発明の目的は、このような問題点を改善し、電子写真方式で用いる感光体の劣化試験に好適であって、構成および操作が単純でかつ精度の高い感光体劣化加速試験装置を提供することにある。
【００１１】
【課題を解決するための手段】
請求項１に記載の発明は、電子写真感光体を高速で回転させ、帯電装置による静電気帯電工程と露光装置による光放電工程とを含むサイクルを、繰り返し実行して前記電子写真感光体の劣化を加速させる感光体劣化加速試験装置において、前記電子写真感光体の通過電流と表面電位を計測する計測手段と、この計測手段による計測結果に基づいて前記表面電位を一定条件に保つように制御する制御手段とを備えたことに特徴がある。
【００１２】
電子写真感光体（電子写真像形成部材）を高速で回転させ、静電気帯電工程と光放電工程を含むサイクルを繰り返しかけて感光体の劣化を加速させる試験システムにおいて、感光体の通過電流・表面電位を計測し、電位を一定条件に保つように制御することにより、劣化加速状況を的確に判断できることとなる。
【００１３】
請求項２に記載の発明は、請求項１において、前記制御手段は、電子写真感光体の通過電流と表面電位の計測結果に基づき、前記電子写真感光体を帯電させるコロナ帯電器の出力を変動させることで、前記表面電位を一定条件に保つように制御することに特徴がある。
【００１４】
電子写真感光体の通過電流と表面電位を計測し、電子写真感光体を帯電させるコロナ帯電器の出力のみ制御し、表面電位を一定条件に保つようにすることにより、劣化加速試験のシステム構築が容易になる。
【００１５】
請求項３に記載の発明は、請求項２において、前記制御手段は、電子写真感光体の通過電流と表面電位の計測結果に基づき、前記電子写真感光体を帯電させるコロナ帯電器の出力を自動的に変動させることで、前記表面電位を一定条件に保つように制御することに特徴がある。
【００１６】
電子写真感光体の通過電流と表面電位を計測し、感光体を帯電させるコロナ帯電器の出力を自動で制御させ、表面電位を一定条件に保つようにすることにより、人手によるバラツキを無くして、無人化による劣化加速試験の精度および効率を向上させることとなる。
【００１７】
請求項４に記載の発明は、請求項１において、前記制御手段は、電子写真感光体の通過電流と表面電位の計測結果に基づき、前記電子写真感光体を露光させる露光装置の出力を変動させることで、前記表面電位を一定条件に保つように制御することに特徴がある。
【００１８】
電子写真感光体の通過電流と表面電位を計測し、前記電子写真感光体を露光させる露光装置の出力のみを制御し、表面電位を一定条件に保つようにすることにより、劣化加速試験のシステム構築を容易にする。
【００１９】
請求項５に記載の発明は、請求項４において、前記制御手段で、電子写真感光体の通過電流と表面電位の計測結果に基づき、前記電子写真感光体を露光させる露光装置の出力を自動的に変動させることで、前記表面電位を一定条件に保つように制御することに特徴がある。
【００２０】
電子写真感光体の通過電流と表面電位を計測し、前記電子写真感光体を露光させる露光装置の出力を自動で制御し、表面電位を一定条件に保つようにすることにより、人手によるバラツキを無くし、無人化による劣化加速試験の精度および効率が向上することとなる。
【００２１】
請求項６に記載の発明は、請求項３または５において、前記電子写真感光体の通過電流の計測結果から、前記電子写真感光体の通過電荷量を算出する電荷算出手段を備えたことに特徴がある。
【００２２】
劣化加速試験中、計測した通過電流から電子写真感光体の通過電荷量を算出するシステムを備えたことにより、電子写真感光体の正確な劣化加速状況が判断可能となる。
【００２３】
請求項７に記載の発明は、請求項６において、前記電子写真感光体の通過電荷量が予め設定した条件を満たした時点で、自動的に劣化試験を終了することに特徴がある。
【００２４】
感光体劣化加速試験装置において、必要とする通過電荷量が満たされた時点で、自動的に劣化試験が終了することにより、正確な試験を実施することとなる。
【００２５】
請求項８に記載の発明は、請求項７において、前記制御手段で、電子写真感光体の特性を測定することに特徴がある。
【００２６】
感光体劣化加速試験装置において、感光体の特性（帯電特性、感度など）も測定することができる事により、時間効率の向上と評価・試験装置をコンパクト化できることとなる。
【００２７】
請求項９に記載の発明は、請求項８において、前記帯電装置は、特性測定用の帯電装置と加速劣化試験用の帯電装置に分かれていることに特徴がある。
【００２８】
感光体劣化加速試験装置において、帯電装置が特性測定用と加速劣化試験用とでそれぞれ分かれていることにより、帯電装置を長寿命化すると共に時間効率を向上させることとなる。
【００２９】
請求項１０に記載の発明は、請求項９において、前記特性測定用の帯電装置と加速劣化試験用の帯電装置を切り替える切替手段を設けたことに特徴がある。
【００３０】
感光体劣化加速試験装置において、帯電装置を特性測定用と加速劣化試験用に切り替えるための切替スイッチを設けることにより、特性測定用・劣化加速試験用それぞれの帯電装置の電源が必要無くなり、装置をコンパクト化する事を目的とする。
【００３１】
請求項１１に記載の発明は、請求項１０において、前記露光装置は、特性測定用の露光装置と加速劣化試験用の露光装置に分かれていることに特徴がある。
【００３２】
感光体劣化加速試験装置において、露光装置が特性測定用と加速劣化試験用とでそれぞれ分かれていることにより、測定用光源の多様化に対応可能となる。
【００３３】
請求項１２に記載の発明は、請求項１１において、前記特性測定用の露光装置で使用する波長を切り換えるためのフィルタ交換装置を備えたことに特徴がある。
【００３４】
感光体劣化加速試験装置において、測定用露光装置にフィルタ交換機能を設けたことにより、様々な波長に対する光応答性が確認可能となる。
【００３５】
請求項１３に記載の発明は、請求項１２において、前記電子写真感光体の劣化加速試験終了後、前記電子写真感光体の特性を自動的に測定することに特徴がある。
【００３６】
感光体劣化加速試験装置において、電子写真感光体の劣化加速試験終了後、自動的に感光体の特性を測定することにより、劣化加速試験終了直後の正確な特性を測定することができる。
【００３７】
【発明の実施の形態】
以下、本発明の実施の一形態を図面を用いて説明するが、本発明はこれに限定されるものではなく、電子写真感光体を高速で回転させ、静電気帯電工程と光放電工程とを含むサイクルを繰り返し実行する感光体劣化加速試験装置であって、前記電子写真感光体の通過電流と表面電位を計測し、計測結果に基づいて電位を一定条件に保つように制御する感光体劣化加速試験装置の広範囲な応用を含むものである。
【００３８】
図１に、本発明の実施の一形態に係る劣化加速試験装置の概略を示し、図２にその劣化加速試験装置のターンテーブル下の配置を示す。
【００３９】
図１において、ターンテーブル１は、コントローラ９の制御で軸周りに回転可能であって、前記ターンテーブル１には、開口部３を設け、この開口部３を覆うように感光面を下向きに載置した試料片を、試料押え板２で押さえてセットするように構成されている。こうして、試料片をセットした後、テーブル下部から開口部３を通して帯電・露光処理することとなる。
【００４０】
また、ターンテーブル１の下部には、特性測定用および劣化加速試験用に分かれたコロナ帯電器４と、表面電位計７の電極部５および特性測定用および劣化試験用に分かれた露光装置（図２に示す）が配置されている。図２に示すように、コロナ帯電器４、電極部５および前記露光装置の配置は、ターンテーブル１の回転軸を中心として、特性測定用コロナ帯電器１０と特性測定用露光装置１２が対向し、また、劣化加速試験用コロナ帯電器１１と劣化加速試験用露光装置１３が対向するようになされている。また、特性測定用コロナ帯電器１０と劣化加速試験用コロナ帯電器１１の切り替えは、切替スイッチ１４で切り替えるように構成している。さらに、本実施形態では、特性測定用露光装置１２が測定目的に応じて様々な波長に切り替え可能なように、フィルタ交換装置を具備している。
【００４１】
なお、本実施形態において、切替スイッチ１４によるりコロナ帯電器１０、１１の切り替え、および前記フィルタ交換装置による波長の切り替えは、コントローラ９からの指令で自動的に行うが、これに限らず、マニュアル操作で任意に切り替えるようにしてもよい。
【００４２】
また、コントローラ９は、Ａ／Ｄ変換器８などのインタフェースを介し、電流計測・平滑化回路などを備えた電流計６、表面電位計７の本体などと接続され、電流計６、表面電位計７などの計測結果（感光体の通過電流と表面電位など）に基づき、電位を一定に保つように制御する。例えば、電流計６、表面電位計７から特性測定情報を取得し、ターンテーブル１の回転駆動や帯電・露光動作を制御する（コロナ帯電器または露光装置の出力を制御する）。
【００４３】
この構成により、特性測定を行う場合は、前述のように感光体試料片をその感光面が下向きになるようにターンテーブル１の開口部３にセットし、コントローラ９の制御で、コロナ帯電器４（特性測定用コロナ帯電器１０）により試料片の感光面を帯電処理する。この間、感光体の試料片がコロナ帯電器４に対向静止するような位置でターンテーブル１を停止することができる。また、実施機と同程度のスピードでターンテーブル１を回転することができる。また、試料片を帯電させて帯電の立ちあがりの様子を観察するため、ターンテーブル１を高速で回転させ、前記試料片をセットした開口部３がコロナ帯電器４上を何度も通過させることができる。
【００４４】
ここで、コロナ帯電器４から試料片に与えられ、試料片を充電するパルス電流は、電流計６に送られ、その中の平滑化回路で平滑化などの処理がなされた後、Ａ／Ｄ変換器８でＡ／Ｄ変換され、コントローラ９に送られて演算処理される。
【００４５】
また、試料片の表面電位は、コロナ帯電器４と別の位置に配置された表面電位計７のモニタ部（本体）でモニタされ、モニタされた信号は、表面電位計７に送られ、その中の増幅器で増幅処理などがなされた後、Ａ／Ｄ変換器８でＡ／Ｄ変換され、コントローラー９に送られて演算処理される。
【００４６】
また、劣化加速試験を行う場合は、ターンテーブル１を高速で回転させ、劣化試験用コロナ帯電器１１で試料片の感光面を帯電処理し（静電気帯電工程）、その後、露光装置１３によって光放電処理を実施する（光放電工程）。これらの処理を繰り返し行うことによって、感光層中の電荷を強制的に通過させ、実施機よりも早く寿命を判断するものである。
【００４７】
本実施形態では、電流計６、表面電位計７、コントローラ９などが前記計測手段を構成し、コントローラ９などが前記制御手段を構成し、コントローラ９などが前記電荷算出手段を構成し、切替スイッチ１４、コントローラ９などが前記切替手段を構成する。
【００４８】
【実施例】
［第１の実施例］
本実施例では、ターンテーブル（図１の１に相当）を持つ測定器として、（株）川口電気製作所製の静電気帯電試験装置（ＥＰＡ８１００）を利用した。また、電子写真感光体の試料片として、リコーＳＰ２０００用感光体と同じ材料・処方構成の試料片を用いた。
【００４９】
前記静電気帯電試験装置を利用して前述の実施形態に相当する感光体劣化加速試験装置を構成し、まず、試料片をターンテーブル開口部（図１の３に相当）にセットし、ターンテーブルを１０００ｒ．ｐ．ｍまで回転させ、安定した所で劣化加速試験を行った。露光装置（図２の１３に相当）の出力を一定（３０μＷ／ｃｍ²）にし、コロナ帯電器（図１の４に相当）の出力を制御して感光体の表面電位を一定にし、試験中の計測した通過電流から通過電荷量を算出させるようにした。
【００５０】
ここで、本実施例の劣化加速試験中の制御方法は、感光体の表面電位がそれぞれの水準において５Ｖ以上小さくなった場合、コロナ帯電器（図２の１１）の電源電圧の出力を上げ、感光体の表面電位がそれぞれの水準において５Ｖ以上大きくなった場合には、コロナ帯電器の電源電圧の出力を下げるというものである。
【００５１】
図３に、本実施例の劣化加速試験中における感光体の表面電位を４水準に振った時の、通過電荷量と残留電位の関係グラフを示す。この関係グラフから、劣化加速試験中の電位の違いにより劣化加速試験後の残留電位に差が出てくることがわかる。よって、劣化加速試験中の電位を所定の値に決定しないと、劣化加速試験の正確性を欠くこととなり、劣化加速試験中の電位は、一定にするよう制御しなければいけないことがわかる。また、制御方法は一つの因子をフィードバック制御するだけで、劣化加速試験を行えるため、二つの因子を制御する従来の技術に比べて、システム構築が簡単になることがわかる。
【００５２】
さらに、通過電荷量を算出する機能により、実際にプリントアウトした枚数を容易に計算でき、感光体の正確な劣化加速状況を判断することができる。具体的には、実際の複写機においてのＡ４サイズ１枚の通過電荷量Ｑは、静電容量をＣ、帯電後の電位をＶｄ、露光後の電位をＶｒとした時、Ｑ＝Ｃ×（Ｖｄ−Ｖｒ）からＡ４サイズ１枚の通過電荷量が求まり、劣化加速試験で算出された通過電荷量Ｑａはわかっているので、算出された通過電荷量ＱａからＡ４サイズ１枚の通過電荷量Ｑを除算することで、実際のプリントアウト枚数が容易に求まる。本実施例の場合、通過電荷量が２．０７（ｍＣ／cm²）の時は、約３０，０００枚プリントアウトしたことになる。
【００５３】
［第２の実施例］
本実施例では、ターンテーブル（図１の１に相当）を持つ測定器として、（株）川口電気製作所製の静電気帯電試験装置（ＥＰＡ８１００）を利用した。また、電子写真感光体の試料片として、サンプル１（リコーＩＰＳＩＯＣＯＬＯＲ５０００用感光体）、サンプル２（リコーＳＰ１０用感光体）、サンプル３（リコーＳＰ２０００用感光体）を用いた。
【００５４】
前記静電気帯電試験装置を利用し、感光体劣化加速試験を行うにあたり、コロナ帯電器（図２の１１に相当）の出力を一定（電源電圧：−６ｋＶ）として、露光装置の出力を適宜、変更するように制御し、感光体の通過電流、表面電位を計測し、感光体の表面電位が一定になるようにして、試験中の通過電流から通過電荷量を算出し、必要とする通過電荷量が満たされた時に自動的に劣化加速試験が終了するようにした感光体劣化加速試験装置を使用した場合を「実施例２」とした。この実施例２の制御方法は、感光体の表面電位が−８０５Ｖ以下になった場合、露光装置の出力を上げ、感光体の表面電位が−７９５Ｖ以上になった場合、露光装置の出力を下げるというものである。
【００５５】
また、実施例２と比較するため、他の制御方法によるものを実施した。すなわち、露光装置の出力を一定（照度：２５ｌｕｘ）として、コロナ帯電器の出力を適宜、変更するように制御し、感光体の通過電流、表面電位を計測し、感光体の表面電位が一定になるように制御して、試験中の通過電流から通過電荷量を算出し、必要とする通過電荷量が満たされた時に自動的に劣化加速試験が終了する感光体劣化加速試験装置を使用した場合を「実施例２ａ」とした。この実施例２ａの制御方法は、感光体の表面電位が−８０５Ｖ以下になった場合、コロナ帯電器の電源電圧を小さくし、感光体の表面電位が−７９５Ｖ以上になった場合、コロナ帯電器の電源電圧を上げるというものである。
【００５６】
前記実施例２および実施例２ａにおいて、感光体の種類の違い（特性の違い）による、劣化加速試験に費やした時間を表１に示し、劣化加速試験終了後の残留電位の結果を表２に示す。ここで、前述のサンプル１〜３をターンテーブル開口部にセットし、ターンテーブルの回転（１０００ｒ．ｐ．ｍ）終了後、劣化加速試験をスタートさせた。また、劣化加速試験中の表面電位：−８００Ｖ、劣化加速試験終了条件：通過電荷量１．０３ｍＣ／cm²であった。
【表１】

【表２】

表１、表２から、露光装置の出力を制御させて、感光体の表面電位を一定に制御させる場合においても、一つの因子をフィードバック制御するだけで、劣化加速試験を行えるため、第１の実施例と同様に二つの因子を制御する前記従来の技術に比べて、システム構築が簡単になることがわかる。また、表２から、露光装置の出力を制御して、感光体の表面電位を一定に制御する場合と、コロナ帯電器の出力を制御して、感光体の表面電位を一定に制御する場合による劣化加速度の違いは見られないことがわかる。つまり、どちらの試験方法（あるいは試験装置）で劣化加速試験を行っても、同じように劣化を加速することができ、結果の違いは発生しないことがわかる。なお、実施例２と実施例２ａで、残留電位に違いがあるが、これは装置上の誤差である。
【００５７】
また、表１、表２の結果から、感光体の特性の違いにより劣化加速試験が終了する時間が変化することがわかる。よって、試験中に通過電流から通過電荷量を算出し、必要とする通過電荷量が満たされた時点で自動的に劣化加速試験が終了するシステムであれば、終了時間に拘らず、劣化加速試験を行うことができ、人手をかけずに試験を正確に行うことができる。さらに、感光体の特性の違いにより劣化加速試験が終了する時間が変化するため、劣化加速試験終了後、自動的に測定が行われるように構成した装置では、試験者が終了時間を見計らって確認したりすることが不要となり、人手をかけずに試験を正確に行うことができる。
【００５８】
［第３の実施例］
本実施例では、ターンテーブル（図１の１に相当）を持つ測定器として、（株）川口電気製作所製の静電気帯電試験装置（ＥＰＡ８１００）を利用し、感光体劣化加速試験装置を構成した。この構成により、感光体劣化加速試験を行うにあたって、コロナ帯電器の出力を適宜、変動可能に制御して、露光装置の出力を一定（２５ｌｕｘ）に制御し、感光体の通過電流、通過電流を計測して、感光体の表面電位を一定にさせるよう制御し、試験中に通過電流から通過電荷量を算出して、必要とする通過電荷量が満たされた時には、自動的に劣化加速試験が終了するようにした。
【００５９】
ここで、信号に瞬間的なバラツキが無く、劣化加速試験が行われた場合を「実施例３」とし、強制的に露光装置の出力に変化（露光量を上げ）を与えた場合を「実施例３ａ」とし、その時の劣化加速試験に費やした時間と劣化加速試験終了後の残留電位の結果を表３に示す。前記劣化加速試験では、サンプルをターンテーブル開口部にセットし、ターンテーブル１０００ｒｐｍ終了後、劣化加速試験をスタートさせた。また、前記サンプルとしては、「リコーＩＰＳＩＯＣＯＬＯＲ５０００用感光体」を用い、劣化加速試験中の表面電位を−８００Ｖとし、劣化加速試験終了条件を通過電荷量：１．０３ｍＣ／cm²とした。
【表３】

表３から、本実施例の感光体劣化加速試験装置では通過電荷量を算出しているため、電流の変化に対応できることがわかる。また、残留電位の結果（違いが見られるが、装置上の誤差である。）を見てわかるように、劣化試験も正しく行われていることがわかる。よって、前記従来の技術で示した感光体劣化加速試験システム（帯電装置、露光装置の両方を制御することにより、感光体の表面電位、感光体の通過電流を一定にさせ、ある一定時間行う劣化加速試験システム）では、バラツキなどに対応できなかったが、本実施例の劣化加速試験装置では対応できるシステムになっていることがわかる。
【００６０】
[第４の実施例]
本実施例では、前述の実施形態に準じ、特性測定用の帯電装置（図２の１０に相当）および露光装置（図２の１２に相当）と、劣化加速試験用の帯電装置（図２の１１に相当）および露光装置（図２の１３に相当）とがそれぞれ分かれている測定器を使用した場合「実施例４」と、帯電装置が特性測定用、劣化加速試験用とも共通で、露光装置が特性測定用と劣化加速試験用とで分かれている場合「比較例４」と、帯電装置が特性測定用と劣化加速試験用とで分かれており、露光装置が特性測定用、劣化加速試験用とも共通の場合「比較例４ａ」と、帯電装置、露光装置とも特性測定用と劣化加速試験用とで共通（露光装置のフィルタ交換不可）の場合「比較例４ｂ」と、特性測定用と劣化加速試験用とでそれぞれ別の測定器を使用する場合「比較例４ｃ」について、試験を行った。この場合、サンプルとしては、「リコーＩＰＳＩＯＣＯＬＯＲ５０００用感光体の試料片を使用した。
【００６１】
ここで、前述の実施例４および比較例４、４ａ、４ｂ、４ｃの違いを表４に示す。表４において、「実験１」は、コロナ帯電器の出力を一定として露光装置を制御し、感光体の通過電流、表面電位を計測して、感光体の表面電位が一定−８００Ｖになるよう制御し、試験中の通過電流から通過電荷量を算出して、必要とする通過電荷量が満たされた時点で劣化加速試験が終了するような劣化加速試験において、通過電荷量が２．０７ｍＣ／cm²となるまでに費やす時間を示す。この時間は、測定器の立ち上げから立ち下げまでに費やす時間と、劣化加速試験以外に４回特性測定を行った時間との合計の時間である。
【表４】

本実施例の結果を示す表４から、帯電装置が特性測定用と劣化加速試験用とで共通である場合、帯電装置の寿命が短くなってしまうことがわかる。また、測定の度に校正を行わなければならないため、劣化加速試験終了後の測定を即座に開始することができず、特性値の正確性に欠けることが有り得る。
【００６２】
ここで、露光装置が特性測定用と劣化加速試験用とで同じである場合は、光源が白色光であるため（リコーＩＰＳＩＯＣＯＬＯＲ５０００用感光体の試料片の感度測定は７８０ｎｍの単色光測定のため）、感度測定ができず、他の光源に関しても対応できない、つまり光源を切り替える機構がついていないと測定できない。また、特性測定用と劣化加速試験用とでそれぞれが別の測定器を用いた場合は、装置が大型化し、コストが高くなる問題だけでなく、劣化加速試験に費やす時間にまでも影響が出てしまうこととなる。
【００６３】
【発明の効果】
請求項１に記載の発明によれば、電子写真感光体を高速で回転させ、静電気帯電工程と光放電工程を含むサイクルを繰り返しかけて感光体の劣化を加速させる試験システムにおいて、感光体の通過電流と表面電位を計測し、表面電位を一定条件に保つように制御させることにより、劣化加速状況を判断できる劣化加速システムを構築できる。
【００６４】
請求項２に記載の発明によれば、感光体を帯電させるコロナ帯電器の出力のみ制御させ、感光体の通過電流と表面電位を計測し、表面電位を一定条件に保つように制御させることにより、劣化加速試験のシステム構築を容易に行うことができる。
【００６５】
請求項３に記載の発明によれば、感光体を帯電させるコロナ帯電器の出力を自動で制御させ、感光体の通過電流と表面電位を計測し、表面電位を一定条件に保つように制御させることにより、人手によるバラツキを無くし、無人化による劣化加速試験の効率を向上させることができる。
【００６６】
請求項４に記載の発明によれば、感光体を露光させる露光装置の出力のみを制御させ、感光体の通過電流と表面電位を計測し、表面電位を一定条件に保つように制御させることにより、劣化加速試験のシステム構築を容易に行うことができる。
【００６７】
請求項５に記載の発明は、感光体を露光させる露光装置の出力を自動で制御させ、感光体の通過電流と表面電位を計測し、表面電位を一定条件に保つように制御させることにより、人手によるバラツキを無くし、無人化による劣化加速試験の効率を向上させることができる。
【００６８】
請求項６に記載の発明によれば、劣化加速試験中、計測した通過電流から感光体の通過電荷量を算出するシステムを備えたことにより、感光体の正確な劣化加速状況が判断できる。
【００６９】
請求項７に記載の発明によれば、必要とする通過電荷量が満たされた時点で、自動的に劣化試験が終了されることにより、正確な試験を行うとことができる。
【００７０】
請求項８に記載の発明は、感光体の特性（帯電特性、感度）も測定することができ、時間効率の向上と装置のコンパクト化が可能である。
【００７１】
請求項９に記載の発明によれば、帯電装置が特性測定用、加速劣化試験用でそれぞれ分かれていることにより、帯電装置の長寿命化と時間効率向上が可能である。
【００７２】
請求項１０に記載の発明によれば、帯電装置を特性測定用と加速劣化試験用に切り替えるためのスイッチを設けることにより、特性測定用、劣化加速試験用それぞれの帯電装置の電源が必要無くなり装置のコンパクト化が可能である。
【００７３】
請求項１１に記載の発明によれば、露光装置が特性測定用、加速劣化試験用でそれぞれ分かれていることにより、測定用光源の多様化が可能である。
【００７４】
請求項１２に記載の発明によれば、複写機に高画質化が求められ、それに伴い露光用ビームの波長も短波長化されてきている。そこで測定用の露光装置にフィルタ交換機能が設けられていることにより、様々な波長の光応答性の確認が可能である。
【００７５】
請求項１３に記載の発明によれば、感光体の劣化加速試験終了後、自動的に感光体の特性を測定できることにより、劣化加速試験終了直後の正確な特性を測定することが可能である。
【００７６】
以上説明したように、本発明によれば、電子写真感光体の劣化試験に好適であって、構成および操作が単純でかつ精度の高い感光体劣化加速試験装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の実施の一形態に係る感光体劣化加速試験装置の全体構成図である。
【図２】本発明の実施の一形態に係る感光体劣化加速試験装置でターンテーブル下部の帯電器および露光装置の配置を示す図である。
【図３】本発明の実施の一形態に係る感光体劣化加速試験で通過電荷量と残留電位の関係を示す図である。
【符号の説明】
１ターンテーブル
２押え板
３開口部
４、１０、１１コロナ帯電器
５電極部
６電流計
７表面電位計
８Ａ／Ｄ変換器
９コントローラ
１２、１３露光装置
１４切替スイッチ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a characteristic determination method and a diagnostic apparatus for a photoreceptor used in an electrophotographic system.
[0002]
[Prior art]
Since a photoreceptor used in an electrophotographic process is used repeatedly, a test / evaluation method for predicting the lifetime of the photoreceptor due to repeated use is an extremely important technique. The life test method is as follows: (1) A photocopier or printer that performs an electrophotographic process is used to repeatedly print on paper, and the life of the photoconductor is judged based on the quality of the output image. The charging potential and post-exposure potential are measured, and the lifetime is predicted by fluctuations in these potentials. Since this method is usually performed in an implementation machine on which a photoconductor is mounted, a reliable lifetime is achieved. While it can be predicted, a life test cannot be performed until the implementation machine is completed. For example, assuming that the A4 size printout capacity is 10 sheets / minute, it takes 16.6 days to test 10,000 minutes ... 10 hours a day to print out 100,000 sheets.
[0003]
For this reason, as another method, (2) charging with a charger or exposure device disposed around the photosensitive member in a state where the photosensitive member is rotated at a high speed (1,000 to 2,000 rpm), There is a method for predicting the lifetime by repeating exposure. This method is further divided into two test methods. One is that the output of the charger and the amount of light from the exposure device are fixed under predetermined conditions, the test is performed for a predetermined time, and then the characteristics of the photoconductor are measured to determine the deterioration state. Is. The second method is to measure the post-exposure potential V and the passing current I flowing through the photoconductor during the test, and adjust the output of the charger and the light quantity of the exposure device so that these two are always at a predetermined level. This is a method performed while adjusting.
[0004]
The important point in the two methods (2) is that the current passing through the photoconductor during the test is measured and converted into a charge amount (value per unit area) Q, while one A4 size sheet is converted. Assuming that the size of the photoconductor is the size that allows one A4 size sheet to be printed without overlapping the photoconductor when printing out by the execution machine, the passing current flowing through the photoconductor will cause the electrostatic capacity of the photoconductor to increase. Since C (value per unit area) and charging potential V are obtained by “C · V”, the life test time can be made to correspond to the number of printed sheets of the machine by setting “Q / C · V”. Is a point.
[0005]
Another important point is that this test is an accelerated life test. Specifically, the photoreceptor is 5.6 μA / 19.6 cm. ² When a 20 Hr test was conducted (2 days for a test of 10 hours per day), 5.6 / 19.6 × 10 ^-6 × 20 × 60 × 60 = 0.02057 (C / cm ² ) Has passed through the photoconductor. Assuming that printing is performed with A4 paper longitudinal feed, the electrostatic capacity of the photoreceptor is 100 (pF / cm). ² ), A charging potential of −700 (V), and a post-exposure potential including after neutralization of 0 (V), 100 × 10 ^-12 × 700 = 7 × 10 ^-6 (C / cm ² ) Is a charge passing through the photoconductor when printing out one A4 size sheet, so 0.02057 / (7 × 10 ^-6 ) ≈294,000 (sheets) have been printed out, and the life test will be greatly accelerated. For this reason, the life test is often performed by the method (2).
[0006]
However, as can be seen from the specific calculation described above, if the current passing through the photosensitive member is constant during the test, it is easy to calculate how many printouts of the test have been performed. For this reason, the test is generally performed with a constant passing current. (The essence is to know the passing charge amount.) Also, depending on the level of the charged potential, depending on the photoreceptor, the result of the life test may differ, and the test should be performed with the charged potential kept constant. Is required.
[0007]
Therefore, in order to make the charging potential and the passing current constant, a system for adjusting the high voltage power supply output of the charger and adjusting the light amount of the exposure apparatus is required, and a conventional life test apparatus has been constructed.
[0008]
Japanese Patent Application No. 5-1973 is related to this type of apparatus.
[0009]
[Problems to be solved by the invention]
However, in the above-described system, the relationship between the two measured amounts, the surface potential X, the passing current Y, the two manipulated variables, the output control value A of the charger high-voltage power supply, and the output control value B of the discharge exposure lamp light amount is A When X increases, X and Y increase, when A decreases, X and Y also decrease, when B increases, X decreases, Y increases, when B decreases, X increases, Y is If X deviates from the target value, and if A or B is manipulated so that it falls within the target range, another measurement amount Y changes, and disturbances act on Y. Then, if A or B is manipulated to maintain this within the target range, X will change this time, and very complicated control must be performed. In the above system, even if there is an instantaneous variation in the photoreceptor surface potential and the passing current during the deterioration acceleration test, these are not reflected in the calculation of the passing charge amount as an instantaneous error.
[0010]
Accordingly, an object of the present invention is to improve a photoconductor deterioration acceleration test apparatus which is suitable for a deterioration test of a photoconductor used in an electrophotographic method and which has a simple configuration and operation and high accuracy. It is to provide.
[0011]
[Means for Solving the Problems]
According to the first aspect of the present invention, the electrophotographic photosensitive member is rotated at a high speed, and a cycle including an electrostatic charging step by a charging device and a photodischarge step by an exposure device is repeatedly executed to deteriorate the electrophotographic photosensitive member. In the acceleration test apparatus for accelerating photoreceptor deterioration, a control means for measuring a passing current and a surface potential of the electrophotographic photoreceptor, and a control for controlling the surface potential to be maintained at a constant condition based on a measurement result by the measurement means. And a means.
[0012]
In a test system that rotates an electrophotographic photosensitive member (electrophotographic image forming member) at high speed and accelerates deterioration of the photosensitive member by repeating a cycle including an electrostatic charging step and a photodischarge step, the passing current and surface potential of the photosensitive member are accelerated. By measuring the above and controlling the potential so as to keep it at a constant condition, it is possible to accurately determine the deterioration acceleration state.
[0013]
According to a second aspect of the present invention, in the first aspect, the control unit varies the output of the corona charger that charges the electrophotographic photosensitive member based on the measurement result of the passing current and the surface potential of the electrophotographic photosensitive member. Thus, the surface potential is controlled to be maintained at a constant condition.
[0014]
By measuring the passing current and surface potential of the electrophotographic photosensitive member, controlling only the output of the corona charger that charges the electrophotographic photosensitive member, and maintaining the surface potential at a constant condition, a system for accelerated deterioration testing can be constructed. It becomes easy.
[0015]
According to a third aspect of the present invention, in the second aspect, the control unit automatically outputs the output of the corona charger for charging the electrophotographic photosensitive member based on the measurement result of the passing current and the surface potential of the electrophotographic photosensitive member. It is characterized in that the surface potential is controlled so as to be maintained at a constant condition by changing the surface potential.
[0016]
By measuring the passing current and surface potential of the electrophotographic photosensitive member, automatically controlling the output of the corona charger that charges the photosensitive member, and maintaining the surface potential at a constant condition, eliminating manual variations, This will improve the accuracy and efficiency of the accelerated acceleration test due to unmanned operation.
[0017]
According to a fourth aspect of the present invention, in the first aspect, the control unit varies an output of an exposure apparatus that exposes the electrophotographic photosensitive member based on a measurement result of a passing current and a surface potential of the electrophotographic photosensitive member. Thus, the surface potential is controlled to be maintained at a constant condition.
[0018]
Establishing a system for accelerated degradation testing by measuring the passing current and surface potential of the electrophotographic photosensitive member, controlling only the output of the exposure device that exposes the electrophotographic photosensitive member, and maintaining the surface potential at a constant condition To make it easier.
[0019]
According to a fifth aspect of the present invention, in the fourth aspect, the output of the exposure apparatus for exposing the electrophotographic photosensitive member is automatically controlled by the control means based on the measurement result of the passing current and the surface potential of the electrophotographic photosensitive member. It is characterized in that the surface potential is controlled so as to be kept at a constant condition by changing the surface potential.
[0020]
By measuring the passing current and surface potential of the electrophotographic photosensitive member, and automatically controlling the output of the exposure apparatus that exposes the electrophotographic photosensitive member to keep the surface potential at a constant condition, there is no manual variation. Therefore, the accuracy and efficiency of the deterioration acceleration test due to unmanned operation will be improved.
[0021]
The invention described in claim 6 is characterized in that in

claim

3 or 5, the apparatus further comprises charge calculating means for calculating a passing charge amount of the electrophotographic photosensitive member from a measurement result of a passing current of the electrophotographic photosensitive member. There is.
[0022]
By providing a system for calculating the passing charge amount of the electrophotographic photosensitive member from the measured passing current during the deterioration accelerating test, it is possible to determine an accurate deterioration acceleration state of the electrophotographic photosensitive member.
[0023]
A seventh aspect of the invention is characterized in that, in the sixth aspect, the deterioration test is automatically terminated when the passing charge amount of the electrophotographic photosensitive member satisfies a preset condition.
[0024]
In the photoconductor deterioration acceleration test apparatus, when the required passing charge amount is satisfied, the deterioration test is automatically ended, so that an accurate test is performed.
[0025]
The invention according to an eighth aspect is characterized in that, in the seventh aspect, the control means measures characteristics of the electrophotographic photosensitive member.
[0026]
In the photoconductor deterioration acceleration test apparatus, the characteristics (charging characteristics, sensitivity, etc.) of the photoconductor can be measured, so that the time efficiency can be improved and the evaluation / test apparatus can be made compact.
[0027]
The invention described in claim 9 is characterized in that, in claim 8, the charging device is divided into a charging device for characteristic measurement and a charging device for accelerated deterioration test.
[0028]
In the photosensitive member deterioration acceleration test apparatus, the charging device is divided for the characteristic measurement and the acceleration deterioration test, thereby extending the life of the charging device and improving the time efficiency.
[0029]
The invention described in claim 10 is characterized in that, in claim 9, switching means for switching between the charging device for characteristic measurement and the charging device for accelerated deterioration test is provided.
[0030]
In the photoconductor degradation acceleration test device, by providing a changeover switch for switching the charging device between the characteristic measurement and the accelerated degradation test, the power supply for each of the charging device for characteristic measurement and accelerated degradation test is not required, and the device is The purpose is to make it compact.
[0031]
The invention described in claim 11 is characterized in that, in claim 10, the exposure apparatus is divided into an exposure apparatus for characteristic measurement and an exposure apparatus for an accelerated deterioration test.
[0032]
In the photoconductor deterioration acceleration test apparatus, the exposure apparatus is divided for the characteristic measurement and the acceleration deterioration test, so that it is possible to cope with diversification of the measurement light source.
[0033]
A twelfth aspect of the invention is characterized in that, in the eleventh aspect, a filter exchange device for switching the wavelength used in the exposure apparatus for characteristic measurement is provided.
[0034]
In the photoconductor deterioration acceleration test apparatus, the optical response to various wavelengths can be confirmed by providing the measurement exposure apparatus with a filter replacement function.
[0035]
A thirteenth aspect of the present invention is characterized in that, in the twelfth aspect, after completion of the deterioration acceleration test of the electrophotographic photosensitive member, the characteristics of the electrophotographic photosensitive member are automatically measured.
[0036]
In the photoconductor degradation acceleration test apparatus, after the degradation acceleration test of the electrophotographic photoconductor is completed, the characteristics of the photoconductor are automatically measured, so that the accurate characteristics immediately after the degradation acceleration test is completed can be measured.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to this, and includes an electrostatic charging step and a photodischarge step by rotating an electrophotographic photosensitive member at high speed. A photoconductor deterioration acceleration test apparatus that repeatedly executes a cycle, and measures a passing current and a surface potential of the electrophotographic photoconductor, and controls the photoconductor deterioration acceleration test so that the electric potential is maintained at a constant condition based on the measurement result. Includes a wide range of applications for the device.
[0038]
FIG. 1 shows an outline of a deterioration acceleration test apparatus according to an embodiment of the present invention, and FIG. 2 shows an arrangement of the deterioration acceleration test apparatus under a turntable.
[0039]
In FIG. 1, the turntable 1 can be rotated around an axis under the control of a controller 9, and the turntable 1 is provided with an opening 3, and the photosensitive surface is placed downward so as to cover the opening 3. The placed sample piece is configured to be pressed and set by the sample holding plate 2. In this way, after setting the sample piece, charging / exposure processing is performed from the lower part of the table through the opening 3.
[0040]
Further, at the bottom of the turntable 1, a corona charger 4 separated for characteristic measurement and a deterioration acceleration test, an electrode portion 5 of a surface potentiometer 7, and an exposure apparatus separated for characteristic measurement and degradation test (FIG. 2) is arranged. As shown in FIG. 2, the corona charger 4, the electrode unit 5, and the exposure apparatus are arranged such that the characteristic measurement corona charger 10 and the characteristic measurement exposure apparatus 12 face each other about the rotation axis of the turntable 1. In addition, the deterioration acceleration test corona charger 11 and the deterioration acceleration test exposure device 13 face each other. Further, the changeover switch 14 is used to switch between the characteristic measurement corona charger 10 and the deterioration acceleration test corona charger 11. Furthermore, in the present embodiment, a filter replacement device is provided so that the characteristic measurement exposure device 12 can be switched to various wavelengths according to the measurement purpose.
[0041]
In the present embodiment, switching of the

corona chargers

10 and 11 by the changeover switch 14 and switching of the wavelength by the filter exchange device are automatically performed by a command from the controller 9. You may make it switch arbitrarily by operation.
[0042]
The controller 9 is connected to an ammeter 6 having a current measurement / smoothing circuit and the main body of the surface potential meter 7 through an interface such as an A / D converter 8. Control is performed so as to keep the potential constant on the basis of the measurement results such as 7 (passing current and surface potential of the photosensitive member). For example, the characteristic measurement information is acquired from the ammeter 6 and the surface potential meter 7, and the rotation drive and charging / exposure operation of the turntable 1 are controlled (the output of the corona charger or exposure apparatus is controlled).
[0043]
With this configuration, when performing characteristic measurement, the photoconductor sample piece is set in the opening 3 of the turntable 1 so that the photosensitive surface faces downward as described above, and the corona charger 4 is controlled by the controller 9. The photosensitive surface of the sample piece is charged by the (characteristic measuring corona charger 10). During this time, the turntable 1 can be stopped at a position where the sample piece of the photoconductor faces and stops against the corona charger 4. Moreover, the turntable 1 can be rotated at the same speed as the implementation machine. Further, in order to observe the state of rising of the charge by charging the sample piece, the turntable 1 is rotated at a high speed, and the opening 3 in which the sample piece is set passes through the corona charger 4 many times. it can.
[0044]
Here, the pulse current applied to the sample piece from the corona charger 4 and charged to the sample piece is sent to the ammeter 6, and after smoothing or the like is performed by the smoothing circuit therein, the A / D is performed. The signal is A / D converted by the converter 8 and sent to the controller 9 for arithmetic processing.
[0045]
Further, the surface potential of the sample piece is monitored by the monitor unit (main body) of the surface potential meter 7 arranged at a position different from the corona charger 4, and the monitored signal is sent to the surface potential meter 7. After amplification processing and the like are performed by the amplifier in the A / D converter, A / D conversion is performed by the A / D converter 8 and sent to the controller 9 for arithmetic processing.
[0046]
When performing the deterioration acceleration test, the turntable 1 is rotated at a high speed, the photosensitive surface of the sample piece is charged with the deterioration test corona charger 11 (electrostatic charging step), and then light discharge is performed by the exposure device 13. Processing is performed (photodischarge process). By repeating these processes, the charge in the photosensitive layer is forcibly passed, and the lifetime is judged earlier than the execution machine.
[0047]
In the present embodiment, the ammeter 6, the surface potential meter 7, the controller 9 and the like constitute the measurement means, the controller 9 and the like constitute the control means, the controller 9 and the like constitute the charge calculation means, and the changeover switch. 14, the controller 9 and the like constitute the switching means.
[0048]
【Example】
[First embodiment]
In this example, an electrostatic charge test apparatus (EPA8100) manufactured by Kawaguchi Electric Co., Ltd. was used as a measuring instrument having a turntable (corresponding to 1 in FIG. 1). Further, a sample piece having the same material and composition as the Ricoh SP2000 photoconductor was used as a sample piece of the electrophotographic photoconductor.
[0049]
The electrostatic charge test apparatus is used to constitute a photoreceptor deterioration acceleration test apparatus corresponding to the above-described embodiment. First, a sample piece is set in a turntable opening (corresponding to 3 in FIG. 1), and the turntable is set. 1000r. p. The sample was rotated to m and a deterioration acceleration test was conducted at a stable place. The output of the exposure apparatus (corresponding to 13 in FIG. 2) is constant (30 μW / cm ² ), The output of the corona charger (corresponding to 4 in FIG. 1) was controlled to make the surface potential of the photoreceptor constant, and the amount of passing charge was calculated from the passing current measured during the test.
[0050]
Here, the control method during the deterioration acceleration test of the present embodiment increases the output of the power supply voltage of the corona charger (11 in FIG. 2) when the surface potential of the photoreceptor becomes 5 V or more at each level. When the surface potential of the photoconductor becomes larger than 5 V at each level, the output of the power supply voltage of the corona charger is lowered.
[0051]
FIG. 3 is a graph showing the relationship between the passing charge amount and the residual potential when the surface potential of the photoconductor is shifted to four levels during the deterioration acceleration test of this example. From this relationship graph, it can be seen that a difference appears in the residual potential after the accelerated acceleration test due to the difference in potential during the accelerated acceleration test. Therefore, unless the potential during the deterioration acceleration test is determined to be a predetermined value, the accuracy of the deterioration acceleration test is lost, and it is understood that the potential during the deterioration acceleration test must be controlled to be constant. In addition, it can be seen that the control method can perform a deterioration acceleration test only by feedback control of one factor, so that the system construction is simpler than the conventional technique of controlling two factors.
[0052]
Further, the function of calculating the passing charge amount makes it possible to easily calculate the number of actually printed out sheets, and to determine the exact deterioration acceleration state of the photoreceptor. Specifically, the passing charge amount Q of one A4 size sheet in an actual copying machine is Q = C × ((capacitance is C, charged potential is Vd, and exposed potential is Vr). Since the passing charge amount of one A4 size is obtained from Vd−Vr) and the passing charge amount Qa calculated in the deterioration acceleration test is known, the passing charge amount Q of one A4 size sheet is calculated from the calculated passing charge amount Qa. By dividing, the actual number of printouts can be easily obtained. In this example, the passing charge amount is 2.07 (mC / cm ² ), About 30,000 sheets have been printed out.
[0053]
[Second Embodiment]
In this example, an electrostatic charge test apparatus (EPA8100) manufactured by Kawaguchi Electric Co., Ltd. was used as a measuring instrument having a turntable (corresponding to 1 in FIG. 1). Further, Sample 1 (Ricoh IPSIO COLOR5000 photoconductor), Sample 2 (Ricoh SP10 photoconductor), and Sample 3 (Ricoh SP2000 photoconductor) were used as sample pieces of the electrophotographic photoconductor.
[0054]
When performing the photoreceptor deterioration acceleration test using the electrostatic charge test apparatus, the output of the exposure apparatus is appropriately changed with the output of the corona charger (corresponding to 11 in FIG. 2) being constant (power supply voltage: −6 kV). Measure the passing current and surface potential of the photoconductor, calculate the passing charge amount from the passing current under test so that the surface potential of the photoconductor is constant, and the required passing charge amount The case where the photoconductor deterioration acceleration test apparatus in which the deterioration acceleration test is automatically ended when the condition is satisfied is referred to as “Example 2”. In the control method of the second embodiment, when the surface potential of the photosensitive member becomes −805 V or lower, the output of the exposure device is increased, and when the surface potential of the photosensitive member becomes −795 V or higher, the output of the exposure device is decreased. That's it.
[0055]
Further, in order to compare with the second embodiment, another control method was used. That is, the output of the exposure apparatus is constant (illuminance: 25 lux), the output of the corona charger is controlled to be changed as appropriate, the passing current and surface potential of the photoconductor are measured, and the surface potential of the photoconductor is constant. When using a photoreceptor deterioration acceleration test device that calculates the passing charge amount from the passing current under test and automatically completes the accelerated deterioration test when the required passing charge amount is satisfied. Was designated as “Example 2a”. In the control method of Example 2a, when the surface potential of the photoconductor becomes −805 V or less, the power supply voltage of the corona charger is reduced, and when the surface potential of the photoconductor becomes −795 V or more, the corona charger The power supply voltage is increased.
[0056]
In Example 2 and Example 2a, the time spent for the deterioration acceleration test due to the difference in the type (characteristic difference) of the photoreceptor is shown in Table 1, and the results of the residual potential after the deterioration acceleration test are shown in Table 2. Show. Here, the samples 1 to 3 described above were set in the opening of the turntable, and after the turntable rotation (1000 rpm), the deterioration acceleration test was started. Further, the surface potential during the deterioration acceleration test: −800 V, the condition for ending the deterioration acceleration test: a passing charge amount of 1.03 mC / cm ² Met.
[Table 1]

[Table 2]

From Tables 1 and 2, even when the output of the exposure apparatus is controlled and the surface potential of the photoreceptor is controlled to be constant, the deterioration acceleration test can be performed by only feedback controlling one factor. It can be seen that the system construction is simplified compared to the conventional technique in which two factors are controlled as in the embodiment. Further, from Table 2, the output of the exposure apparatus is controlled to control the surface potential of the photosensitive member to be constant, and the output of the corona charger is controlled to control the surface potential of the photosensitive member to be constant. It can be seen that there is no difference in deterioration acceleration. That is, it can be seen that the deterioration acceleration can be accelerated in the same manner regardless of which test method (or test apparatus) is used for the deterioration acceleration test, and the difference in the results does not occur. There is a difference in residual potential between Example 2 and Example 2a, but this is an error on the apparatus.
[0057]
In addition, it can be seen from the results of Tables 1 and 2 that the time required to complete the deterioration acceleration test varies depending on the characteristics of the photoconductor. Therefore, if the system calculates the passing charge amount from the passing current during the test and automatically ends the deterioration acceleration test when the required passing charge amount is satisfied, the deterioration acceleration test is performed regardless of the end time. And the test can be performed accurately without human intervention. Furthermore, because the time at which the accelerated deterioration test ends depends on the characteristics of the photoconductor, the tester will check the end time for the device configured to automatically measure after the accelerated deterioration test. And the test can be performed accurately without human intervention.
[0058]
[Third embodiment]
In this example, an electrostatic charge test apparatus (EPA8100) manufactured by Kawaguchi Electric Co., Ltd. was used as a measuring instrument having a turntable (corresponding to 1 in FIG. 1) to constitute a photoreceptor deterioration acceleration test apparatus. With this configuration, when performing the photoreceptor deterioration acceleration test, the output of the corona charger is controlled to be appropriately variable, the output of the exposure apparatus is controlled to be constant (25 lux), and the passing current and passing current of the photoreceptor are controlled. Measure and control the surface potential of the photoconductor to be constant, calculate the passing charge amount from the passing current during the test, and when the required passing charge amount is satisfied, the deterioration acceleration test is automatically performed. I ended it.
[0059]
Here, the case where there is no instantaneous variation in the signal and the deterioration acceleration test is performed is referred to as “Example 3”, and the case where a change (increased exposure) is forcibly given to the output of the exposure apparatus is Table 3 shows the time spent in the deterioration acceleration test at that time and the residual potential after the deterioration acceleration test. In the deterioration acceleration test, the sample was set in the opening of the turntable, and after the turntable reached 1000 rpm, the deterioration acceleration test was started. As the sample, a “Ricoh IPSIO COLOR 5000 photoconductor” was used, the surface potential during the deterioration acceleration test was set to −800 V, and the condition for ending the deterioration acceleration test was passed charge amount: 1.03 mC / cm. ² It was.
[Table 3]

From Table 3, it can be seen that the photoconductor deterioration acceleration test apparatus of this example calculates the passing charge amount and can cope with a change in current. Further, as can be seen from the result of the residual potential (a difference is seen but it is an error on the apparatus), it can be seen that the deterioration test is correctly performed. Therefore, the photoreceptor deterioration acceleration test system shown in the above-mentioned prior art (controlling both the charging device and the exposure apparatus makes the surface potential of the photoreceptor and the current passing through the photoreceptor constant, and the deterioration performed for a certain period of time. In the acceleration test system), it was found that the system was not able to cope with variations and the like, but the deterioration acceleration test apparatus of the present example was able to cope with it.
[0060]
[Fourth embodiment]
In this example, according to the above-described embodiment, a charging device for characteristic measurement (corresponding to 10 in FIG. 2) and an exposure device (corresponding to 12 in FIG. 2), and a charging device for deterioration acceleration test (in FIG. 2). 11) and an exposure apparatus (corresponding to 13 in FIG. 2) are used. The exposure apparatus is the same as that of “Example 4” and the charging apparatus is used for characteristic measurement and deterioration acceleration test. When the apparatus is separated for characteristic measurement and degradation acceleration test, “Comparative Example 4” and the charging apparatus are separated for characteristic measurement and degradation acceleration test, and the exposure apparatus is for characteristic measurement and degradation acceleration test. “Comparative Example 4a” for both the charging device and the exposure device, and “Comparative Example 4b” for the characteristic measurement and the deterioration acceleration test for both the charging device and the exposure device (exposure device filter exchange not possible). When using separate measuring instruments for the accelerated acceleration test Comparative Example 4c ", was tested. In this case, a sample piece of a photoreceptor for Ricoh IPSIO COLOR5000 was used as a sample.
[0061]
Here, Table 4 shows differences between the above-described Example 4 and Comparative Examples 4, 4a, 4b, and 4c. In Table 4, “Experiment 1” controls the exposure apparatus with the output of the corona charger constant, measures the passing current and surface potential of the photoconductor, and controls the surface potential of the photoconductor to be constant −800V. Then, in the deterioration acceleration test in which the deterioration acceleration test is completed when the required passage charge amount is satisfied by calculating the passage charge amount from the passing current under test, the passage charge amount is 2.07 mC / cm. ² Indicates the time spent until This time is the total time of the time spent from the start-up to the start-up of the measuring instrument and the time when the characteristic measurement is performed four times in addition to the deterioration acceleration test.
[Table 4]

From Table 4 showing the results of this example, it can be seen that when the charging device is common for the characteristic measurement and the deterioration acceleration test, the life of the charging device is shortened. Further, since calibration must be performed for each measurement, the measurement after the deterioration acceleration test cannot be started immediately, and the characteristic value may not be accurate.
[0062]
Here, when the exposure apparatus is the same for the characteristic measurement and the deterioration acceleration test, the light source is white light (sensitivity measurement of the sample piece of the photoreceptor for Ricoh IPSIO COLOR5000 is for measurement of monochromatic light at 780 nm. ), Sensitivity cannot be measured, and other light sources cannot be handled, that is, measurement cannot be performed unless a mechanism for switching the light source is provided. In addition, when separate measuring instruments are used for characteristic measurement and deterioration acceleration test, not only will the equipment become larger and the cost will be increased, but also the time spent on the deterioration acceleration test will be affected. Will end up.
[0063]
【The invention's effect】
According to the first aspect of the present invention, in the test system in which the electrophotographic photosensitive member is rotated at a high speed and the cycle including the electrostatic charging step and the photodischarge step is repeated to accelerate the deterioration of the photosensitive member, the passage of the photosensitive member is performed. By measuring the current and the surface potential and controlling the surface potential so as to maintain a constant condition, it is possible to construct a deterioration acceleration system that can determine the deterioration acceleration state.
[0064]
According to the second aspect of the present invention, by controlling only the output of the corona charger for charging the photoconductor, measuring the passing current and the surface potential of the photoconductor, and controlling the surface potential to be maintained at a constant condition. Therefore, it is possible to easily construct a system for an accelerated deterioration test.
[0065]
According to the third aspect of the present invention, the output of the corona charger for charging the photosensitive member is automatically controlled, the passing current and the surface potential of the photosensitive member are measured, and the surface potential is controlled to be maintained at a constant condition. As a result, it is possible to eliminate the manual variation and to improve the efficiency of the deterioration acceleration test by unmanned operation.
[0066]
According to the invention described in claim 4, by controlling only the output of the exposure apparatus for exposing the photosensitive member, measuring the passing current and the surface potential of the photosensitive member, and controlling the surface potential to be maintained at a constant condition. Therefore, it is possible to easily construct a system for an accelerated deterioration test.
[0067]
The invention according to claim 5 automatically controls the output of the exposure apparatus that exposes the photosensitive member, measures the passing current and the surface potential of the photosensitive member, and controls the surface potential to be maintained at a constant condition. It is possible to eliminate the manual variation and improve the efficiency of the accelerated deterioration test by unmanned operation.
[0068]
According to the sixth aspect of the present invention, an accurate deterioration acceleration state of the photosensitive member can be determined by providing a system for calculating the passing charge amount of the photosensitive member from the measured passing current during the deterioration acceleration test.
[0069]
According to the seventh aspect of the present invention, when the required passing charge amount is satisfied, the deterioration test is automatically terminated, so that an accurate test can be performed.
[0070]
The invention according to claim 8 can also measure the characteristics (charging characteristics, sensitivity) of the photoreceptor, and can improve the time efficiency and make the apparatus compact.
[0071]
According to the ninth aspect of the present invention, since the charging device is divided for the characteristic measurement and the accelerated deterioration test, the life of the charging device can be extended and the time efficiency can be improved.
[0072]
According to the invention described in claim 10, by providing the switch for switching the charging device between the characteristic measurement and the accelerated deterioration test, the power supply of the charging device for characteristic measurement and the accelerated deterioration test is not necessary, and the device Can be made compact.
[0073]
According to the eleventh aspect of the present invention, the exposure light source is divided for the characteristic measurement and the accelerated deterioration test, so that the measurement light source can be diversified.
[0074]
According to the twelfth aspect of the present invention, the copying machine is required to have high image quality, and accordingly, the wavelength of the exposure beam has been shortened. In view of this, it is possible to confirm the photoresponsiveness of various wavelengths by providing a filter replacement function in the exposure apparatus for measurement.
[0075]
According to the thirteenth aspect of the present invention, it is possible to automatically measure the characteristics of the photoconductor after the completion of the deterioration acceleration test of the photoconductor, so that it is possible to measure the accurate characteristics immediately after the end of the deterioration acceleration test.
[0076]
As described above, according to the present invention, it is possible to provide a photoconductor deterioration acceleration test apparatus that is suitable for an electrophotographic photoconductor deterioration test, has a simple configuration and operation, and has high accuracy.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a photoreceptor deterioration acceleration test apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing an arrangement of a charger and an exposure device under a turntable in the photoconductor deterioration acceleration test apparatus according to the embodiment of the present invention.
FIG. 3 is a diagram showing a relationship between a passing charge amount and a residual potential in a photoreceptor deterioration acceleration test according to an embodiment of the present invention.
[Explanation of symbols]
1 Turntable
2 Presser plate
3 openings
4, 10, 11 Corona charger
5 electrodes
6 Ammeter
7 Surface electrometer
8 A / D converter
9 Controller
12, 13 Exposure apparatus
14 changeover switch

Claims

In a photoreceptor deterioration acceleration testing apparatus that rotates an electrophotographic photoreceptor at high speed and repeatedly executes a cycle including an electrostatic charging process by a charging device and a photodischarge process by an exposure apparatus to accelerate the deterioration of the electrophotographic photoreceptor. ,
It comprises a measuring means for measuring a passing current and a surface potential of the electrophotographic photosensitive member, and a control means for controlling the surface potential to be maintained at a constant condition based on a measurement result by the measuring means. Photoconductor deterioration acceleration test equipment.

The control means varies the output of the corona charger for charging the electrophotographic photosensitive member based on the measurement result of the passing current and the surface potential of the electrophotographic photosensitive member so as to keep the surface potential at a constant condition. The photoconductor deterioration acceleration test apparatus according to claim 1, wherein the apparatus is controlled.

The control means automatically changes the output of a corona charger for charging the electrophotographic photosensitive member based on the measurement result of the passing current and the surface potential of the electrophotographic photosensitive member, thereby setting the surface potential to a constant condition. 3. The photoconductor deterioration acceleration test apparatus according to claim 2, wherein the photoconductor deterioration acceleration test apparatus is controlled so as to be maintained.

The control means controls the surface potential to be kept constant by varying the output of an exposure apparatus that exposes the electrophotographic photosensitive member based on the measurement result of the passing current and surface potential of the electrophotographic photosensitive member. The photoconductor deterioration acceleration test apparatus according to claim 1, wherein:

The control means automatically changes the output of the exposure apparatus for exposing the electrophotographic photosensitive member based on the measurement result of the passing current and the surface potential of the electrophotographic photosensitive member, thereby maintaining the surface potential at a constant condition. 5. The photoconductor deterioration acceleration test apparatus according to claim 4, wherein the photoconductor deterioration acceleration test apparatus is controlled as follows.

6. The photoconductor deterioration acceleration test apparatus according to claim 3, further comprising charge calculating means for calculating a passing charge amount of the electrophotographic photosensitive member from a measurement result of a passing current of the electrophotographic photosensitive member. .

The photoconductor deterioration acceleration test apparatus according to claim 6, wherein the deterioration test is automatically terminated when a passing charge amount of the electrophotographic photoconductor satisfies a preset condition.

8. The photoconductor deterioration acceleration test apparatus according to claim 7, wherein the control means measures characteristics of the electrophotographic photoconductor.

9. The photosensitive member deterioration acceleration test apparatus according to claim 8, wherein the charging apparatus is divided into a characteristic measurement charging apparatus and an accelerated deterioration test charging apparatus.

The photosensitive member deterioration acceleration test apparatus according to claim 9, further comprising a switching unit that switches between the characteristic measurement charging apparatus and the acceleration deterioration test charging apparatus.

11. The photoreceptor deterioration acceleration test apparatus according to claim 10, wherein the exposure apparatus is divided into an exposure apparatus for characteristic measurement and an exposure apparatus for an accelerated deterioration test.

12. The photoconductor deterioration acceleration test apparatus according to claim 11, further comprising a filter exchange device for switching a wavelength used in the exposure apparatus for characteristic measurement.

13. The photoconductor deterioration acceleration testing apparatus according to claim 12, wherein after the electrophotographic photoconductor deterioration acceleration test is completed, the characteristics of the electrophotographic photoconductor are automatically measured.