JP3566468B2

JP3566468B2 - Photoconductor life detecting method, image forming apparatus, and process cartridge

Info

Publication number: JP3566468B2
Application number: JP21317896A
Authority: JP
Inventors: 寛明緒方; 令久星加
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1996-07-23
Filing date: 1996-07-23
Publication date: 2004-09-15
Anticipated expiration: 2016-07-23
Also published as: JPH1039691A

Description

【０００１】
【発明の属する技術分野】
本発明は、電子写真画像形成装置に用いる感光体寿命検知方法、前記感光体寿命方法を用いた画像形成装置、及び前記画像形成装置に用いるプロセスカートリッジ、及び前記プロセスカートリッジを着脱可能な電子写真画像形成装置に関する。
【０００２】
ここで電子写真画像形成装置としては、例えば電子写真複写機、電子写真プリンター（例えば、ＬＥＤプリンター、レーザービームプリンター等）、電子写真ファクシミリ装置、及び、電子写真ワードプロセッサー等が含まれる。
【０００３】
またプロセスカートリッジとは、帯電手段、現像手段またはクリーニング手段と電子写真感光体とを一体的にカートリッジ化し、このカートリッジを電子写真画像形成装置本体に対して着脱可能とするものであるか、又は帯電手段、現像手段、クリーニング手段の少なくとも一つと電子写真感光体とを一体的にカートリッジ化して電子写真画像形成装置本体に着脱可能とするものであるか、更に少なくとも現像手段と電子写真感光体とを一体的にカートリッジ化して電子写真画像形成装置本体に着脱可能とするものをいう。
【０００４】
【従来の技術】
従来、電子写真画像形成装置において、電子写真感光体（一般には感光ドラムが多い）の寿命を検知するためには、以下の方法があった。
【０００５】
従来例１：プリント（複写）枚数を積算する方法
最も簡便な方法は、プリント（複写）するサイズが異なる場合であっても、例えば、Ａ４サイズとＡ３サイズの場合も同じ１枚とカウントしてしまうので寿命検知の精度が良くないという欠点があった。又、１ジョブ当りに何枚プリントするかによって１枚当りのドラム回転時間が異なるので寿命検知の精度が良くなかった。
【０００６】
従来例２：帯電量を表面電位センサで検出する方法
この方法は、特開平４−５１２５９号公報の従来技術に開示されている。実際に感光ドラムの帯電電位の低下或いは潜像コントラストの減少を直接表面電位センサにより検知できるので、従来例１に比較して出力画像の状態を反映させた精度の良い寿命検知が可能である。
【０００７】
しかしながら、表面電位センサ及びその出力を処理する電気回路等が必要となり、コストが高くなる。又、長手方向については、センサ位置に対応したドラム上の情報しか判断材料が無いので、部分的な不良に対して弱く、又、センサのばらつき、経時変化等の不安定さも考えると必ずしも正確な寿命検知方法とは言いきれない。
【０００８】
上記従来例１の問題点を解決し、検知精度を上げる方法として以下の方法がある。
【０００９】
特開平５−１８８６７４号公報には、プリント（複写）枚数を積算する代わりに感光ドラムの回転数を積算する方法が開示されている。同様な内容で感光ドラムの回転時間を積算する方法もある。どちらも、プリント枚数を積算する場合に比べて、１回のプリントに対して紙サイズに対応して、紙サイズが大きければ回転数が多くなり、紙サイズが小さければ回転数が少なくなるので紙サイズの違いによる寿命検知の誤差が小さくなる。又、１ジョブ当りのプリント枚数に拘わらず直接ドラムの回転数（回転時間）を積算するので、寿命検知の精度は良いというメリットがある。
【００１０】
この方法をさらに発展させた方法もある。即ち、特開平４−９８２６５号公報には、転写チャージャーが作動したときのみのドラム回転数を積算することにより、実際の画像形成が行われているときのドラム回転数が積算されているので、より正確な寿命検知が可能であることが開示されている。
【００１１】
又、特開平６−１８０５１８号公報によれば、帯電が実行されている間のドラム回転数とクリーニング部材が当接している間のドラム回転数とをそれぞれ積算して、それぞれの設定値（寿命）に対して寿命の判断を行うことが開示されている。
【００１２】
一方、プロセスカートリッジの交換タイミングをユーザに事前に知らせる方法として、以下のものもある。
【００１３】
特開平５−３３３６２６号公報によれば、先ず、プロセスカートリッジをクリーナーと像担持体より構成し、このプロセスカートリッジに記憶素子を設ける。加えて、像担持体の寿命に基づく交換表示動作は、プリント枚数を積算して、像担持体の保証寿命が来たら、使用不可とするために装置を停止させるものであり、保証寿命までの間に、交換時期がせまっていることを表示して準備を促すことと、更に続けて使用すると装置を停止させるときが近付いていることを促す表示をする。
【００１４】
又、トナー収納部内の容量に基づく交換表示動作は、トナー補給用の駆動モーターのオン時間を積算していき、諸々のバラツキを配慮した最悪条件で最も早くくると思われる積算時間で装置を停止させる。この場合も装置を停止させるまでの間に積算時間のある値で交換を促す表示と、又、更に進んだ積算時間で装置を停止させるときが近付いていることを促す表示を出す。又、像担持体寿命に基づく動作とトナー収納部容量に基づく動作は、通常は、プリント枚数が優先されるように設定されているが万が一、像密度が異常に多くて、トナー補給が頻繁に行われて像担持体の保証枚数より早く満杯になってしまいそうな時に、後者の作用が機能するようになっている。
【００１５】
加えて、プロセスカートリッジの交換時に、記憶素子に画像形成装置の一次帯電器の通算通電時間を画像形成装置内に装備したＣＰＵより一括して書き込むと共に、その後の一次帯電器の通算時間を書き込み保存するようにして、使用済みのプロセスカートリッジの記憶素子を回収、解析することにより、この使用済みのプロセスカートリッジを用いていた画像形成装置の現在における像担持体（感光ドラム）の回転数やコロトロンの放電時間等の通算の量が正確に把握でき、プロセスカートリッジ交換のインターバルで、画像形成装置に対する情報収集を行うことができるとしている。
【００１６】
具体的には、プロセスカートリッジ交換時における画像形成装置の像担持体の作動サイクル数、オゾンフィルタの交換時期、像担持体の磨耗データ予測等を把握することができる。しかしながら、この公報においての像担持体の寿命判断はあくまで、プリント枚数によっているので、上述したように、寿命予測の精度は良くない点に変わりはない。
【００１７】
【発明が解決しようとする課題】
近年、一次帯電装置においては、従来用いられてきたコロナ帯電装置に代わり、接触帯電装置が広く用いられるようになってきている。接触帯電装置は従来のコロナ帯電装置に比べて低い印加バイアスで済むこと、オゾンの発生が非常に少ないこと、帯電装置を構成する部品が少なくて済み、安価に提供できるなどの点でメリットが大きい。
【００１８】
その接触帯電装置は、その使用部材の形状により、ブラシ帯電装置とローラ帯電装置に大きく２つに分けられる。ブラシ帯電装置は、ブラシの刷毛目、長期にわたって感光体と当接された場合の毛の倒れ等に問題がある。
【００１９】
一方、ローラ帯電装置においては、均一な帯電を得るためのローラの抵抗調節が必要なこと、ローラを構成するゴムからのブリードによるドラム汚染を防止しなければならないこと、均一な帯電を得るためにローラの形状、表面性等に厳しい制約があることなどの難しい問題がある。
【００２０】
又、帯電部材に印加する電圧には、ＤＣバイアスのみ印加されるもの（以下、ＤＣ帯電という）、ＤＣバイアスにＡＣバイアスを重畳したもの（以下、ＡＣ帯電という）がある。一般に、ＡＣ帯電はＤＣ帯電に比べて均一帯電が可能であるという特徴がある。
【００２１】
更に、ＡＣ帯電には、帯電部材としてローラを用い印加バイアスを放電開始電圧の２倍以上のＡＣ電圧にＤＣ電圧を重畳するもの（特開昭６３−１４９６６９号公報、特開平１−２６７６６７号公報）、帯電部材として導電性ブラシを用い印加バイアスを放電開始電圧の２倍以下のＡＣ電圧にＤＣ電圧を重畳するもの（特開平６−１３０７３２号公報）等がある。
【００２２】
接触帯電のメリットとして、オゾンの発生量が少ない、帯電装置を構成する部品が少なくて済み、安価に提供できることは既に述べたが、反面コロナ帯電に比べて感光ドラムに与えるダメージが大きく、特にＯＰＣドラムにおいてはその傾向が顕著である。
【００２３】
又、同じ接触帯電方法においても、感光ドラムに与えるダメージは、印加電圧によって異なり印加電圧が大きいほどダメージが大きく、ＤＣ電圧のみを印加した場合でもバイアス印加無しでＯＰＣドラムを回転させた場合に比べ増加し、又、ＡＣ電圧を印加すると更にそのダメージ（特にＯＰＣドラムの削れ量）はＤＣ電圧のみを印加した場合の数倍程度に及ぶことが判明した。
【００２４】
特に、放電開始電圧の２倍以上のＡＣ電圧を印加するとこの現象は顕著であるが、放電開始電圧の２倍以下のＡＣ電圧であってもやはりＤＣ電圧のみに比べて数倍程度のダメージはある。
【００２５】
又、ＡＣ電圧の周波数を大きくした場合にもＯＰＣドラムのダメージが増加する傾向にある。
【００２６】
よって、帯電手段としてＡＣ電圧とＤＣ電圧を併用し、又、画像形成中に複数の帯電条件を備えた接触帯電を用いた画像形成装置において感光ドラムの寿命を検知しようとした場合、従来のドラム回転数を用いる寿命検知の方法では、正確な感光ドラムの寿命予測が困難になり、寿命がきていて画像不良が発生していても警告がでなかったり、まだ寿命が来ていないときに警告を出してしまう不都合が生じる恐れがある。
【００２７】
従って、本発明の主な目的は、感光体の正確な寿命検知を行なうための感光体寿命検知方法、前記検知方法を用いた画像形成装置、前記画像形成装置に装着されるプロセスカートリッジ、及びこのプロセスカートリッジを備えた画像形成装置を提供することである。
【００２８】
本発明の他の目的は、電子写真感光体の寿命による交換時期が近いことを正確に検知するための感光体寿命検知方法、前記検知方法を用いた画像形成装置、前記画像形成装置に装着されるプロセスカートリッジ、このプロセスカートリッジを備えた画像形成装置を提供することである。
【００２９】
【課題を解決するための手段】
上記目的は本発明に係る電子写真感光体の寿命検知方法、この検知方法を用いた画像形成装置及びプロセスカートリッジ、このプロセスカートリッジを備えた画像形成装置にて達成される。要約すれば、本発明は、記録媒体に画像を形成する画像形成装置の感光体の寿命検知方法において、
前記感光体を帯電する帯電手段が印加される電圧は、前記感光体が帯電されるときＤＣバイアス成分及びＡＣバイアス成分を含み、前記感光体が除電されるときＤＣバイアス成分なしのＡＣバイアス成分を含み、且つ前記感光体の回転中において、帯電手段へのバイアス印加条件として、ＤＣバイアス成分があるとき及びＤＣバイアス成分がないとき、ＡＣバイアスを印加する第１のバイアス印加条件と、バイアス印加無し、ＤＣバイアスのみ印加、前記ＡＣバイアスの、電圧値又は電流値又は周波数を変化させて印加、の３つのうちの少なくとも１つの第２のバイアス印加条件と、を備えるｎ種類（ｎ≧２）のバイアス印加条件を持ち、
前記画像形成装置本体は、前記バイアス印加条件ｎにおけるそれぞれの時間ｔ１、ｔ２・・・ｔｎと予め決められた係数ｋ１、ｋ２・・・ｋｎを用いて、前記感光体のダメージ指数Ｄを
Ｄ＝ｋ１×ｔ１＋ｋ２×ｔ２＋・・・＋ｋｎ×ｔｎ
（但し、ｔ１はＡＣバイアス印加時間、ｋ１＞０、ｋ２＞０、ｋ３≧０、・・・、ｋｎ≧０）
の式に基づき演算し、前記感光体のダメージ指数Ｄを感光体ダメージ積算値に積算し、積算された積算値と予め定めておいた前記感光体の寿命とする寿命情報とを比較し、該比較結果に基づいて、積算された感光体ダメージ積算値が予め定めておいた前記感光体の寿命とする積算時間以上であるとき、前記感光体の寿命を警告或いは表示することを特徴とする感光体の寿命検知方法である。
【００３１】
本発明の他の態様によれば、記録媒体に画像を形成する画像形成装置の感光体の寿命検知方法において、
前記感光体を帯電する帯電手段が印加される電圧は、前記感光体が帯電されるときＤＣバイアス成分及びＡＣバイアス成分を含み、前記感光体が除電されるときＤＣバイアス成分なしのＡＣバイアス成分を含み、且つ前記感光体の回転中において、帯電手段へのバイアス印加条件として、ＤＣバイアス成分があるとき及びＤＣバイアス成分がないとき、ＡＣバイアスを印加する第１のバイアス印加条件と、バイアス印加無し、ＤＣバイアスのみ印加、前記ＡＣバイアスの、電圧値又は電流値又は周波数を変化させて印加、の３つのうちの少なくと１つの第２のバイアス印加条件と、を備えるｎ種類（ｎ≧２）のバイアス印加条件を持ち、
前記画像形成装置本体は、前記バイアス印加条件ｎにおけるそれぞれの時間ｔ１、ｔ２・・・ｔｎを積算値Ｓ１、Ｓ２・・・Ｓｎに積算し、積算された積算値Ｓ１、Ｓ２・・・Ｓｎと予め決められた係数ｋ１、ｋ２・・・ｋｎを用いて、前記感光体のダメージ指数Ｄを
Ｄ＝ｋ１×Ｓ１＋ｋ２×Ｓ２＋・・・＋ｋｎ×Ｓｎ
（但し、ｔ１はＡＣバイアス印加時間、ｋ１＞０、ｋ２＞０、ｋ３≧０、・・・、ｋｎ≧０）
の式に基づき演算し、前記ダメージ指数Ｄと予め定めておいた前記感光体の寿命とする寿命情報Ｒを比較し、該比較結果に基づいて前記ダメージ指数Ｄが予め定めておいた前記感光体の寿命とする積算時間以上であるとき、前記感光体の寿命を警告或いは表示することを特徴とする感光体の寿命検知方法が提供される。
【００３３】
本発明の他の態様によれば、記録媒体に画像を形成する画像形成装置において、
感光体を帯電する帯電手段を有し、前記帯電手段が印加される電圧は、前記感光体が帯電されるときＤＣバイアス成分及びＡＣバイアス成分を含み、前記感光体が除電されるときＤＣバイアス成分なしのＡＣバイアス成分を含み、且つ前記感光体の回転中において、帯電手段へのバイアス印加条件として、ＤＣバイアス成分があるとき及びＤＣバイアス成分がないとき、ＡＣバイアスを印加する第１のバイアス印加条件と、バイアス印加無し、ＤＣバイアスのみ印加、前記ＡＣバイアスの、電圧値又は電流値又は周波数を変化させて印加、の３つのうちの少なくと１つの第２のバイアス印加条件と、を備えるｎ種類（ｎ≧２）のバイアス印加条件を持ち、前記画像形成装置本体は、前記バイアス印加条件ｎにおけるそれぞれの時間ｔ１、ｔ２・・・ｔｎと予め決められた係数ｋ１、ｋ２・・・ｋｎを用いて、前記感光体のダメージ指数Ｄを
Ｄ＝ｋ１×ｔ１＋ｋ２×ｔ２＋・・・＋ｋｎ×ｔｎ
（但し、ｔ１はＡＣバイアス印加時間、ｋ１＞０、ｋ２＞０、ｋ３≧０、・・・、ｋｎ≧０）
の式に基づき演算する手段と、前記感光体のダメージ指数Ｄを感光体ダメージ積算値に積算する積算手段と、該積算手段により積算された積算値と予め定めておいた前記感光体の寿命とする寿命情報とを比較する手段と、該比較手段の結果に基づいて前記積算手段により積算された感光体ダメージ積算値が予め定めておいた前記感光体の寿命とする寿命情報以上であるとき、前記感光体の寿命を警告或いは表示する警告手段或いは報知手段と、前記記録媒体を搬送する搬送手段と、を有することを特徴とする画像形成装置が提供される。
【００３４】
本発明の他の態様によれば、記録媒体に画像を形成する画像形成装置において、
前記感光体を帯電する帯電手段を有し、前記帯電手段が印加される電圧は、前記感光体が帯電されるときＤＣバイアス成分及びＡＣバイアス成分を含み、前記感光体が除電されるときＤＣバイアス成分なしのＡＣバイアス成分を含み、且つ前記感光体の回転中において、帯電手段へのバイアス印加条件として、ＤＣバイアス成分があるとき及びＤＣバイアス成分がないとき、ＡＣバイアスを印加する第１のバイアス印加条件と、バイアス印加無し、ＤＣバイアスのみ印加、前記ＡＣバイアスの、電圧値又は電流値又は周波数を変化させて印加、の３つのうちの少なくと１つの第２のバイアス印加条件と、を備えるｎ種類（ｎ≧２）のバイアス印加条件を持ち、
前記画像形成装置本体は、前記バイアス印加条件ｎにおけるそれぞれの時間ｔ１、ｔ２・・・ｔｎを積算値Ｓ１、Ｓ２・・・Ｓｎに積算する積算手段と、積算された積算値Ｓ１、Ｓ２・・・Ｓｎと予め決められた係数ｋ１、ｋ２・・・ｋｎを用いて、前記感光体のダメージ指数Ｄを
Ｄ＝ｋ１×Ｓ１＋ｋ２×Ｓ２＋・・・＋ｋｎ×Ｓｎ
（但し、ｔ１はＡＣバイアス印加時間、ｋ１＞０、ｋ２＞０、ｋ３≧０、・・・、ｋｎ≧０）
の式に基づき演算する手段と、該演算手段により演算された感光体ダメージ指数Ｄと予め定めておいた前記感光体の寿命とする寿命情報とを比較する比較手段と、該比較手段の結果に基づいて前記演算手段により演算された感光体ダメージ指数が予め定めておいた前記感光体の寿命とする寿命情報以上であるとき、前記感光体の寿命を警告或いは表示する警告手段或いは報知手段と、前記記録媒体を搬送する搬送手段と、
を有することを特徴とする画像形成装置が提供される。
【００３６】
本発明の他の態様によれば、画像形成装置本体に着脱可能なプロセスカートリッジであって、感光体と、前記感光体を帯電する帯電手段と、を有するプロセスカートリッジにおいて、
前記帯電手段が印加される電圧は、前記感光体が帯電されるときＤＣバイアス成分及びＡＣバイアス成分を含み、前記感光体が除電されるときＤＣバイアス成分なしのＡＣバイアス成分を含み、且つ前記感光体の回転中において、帯電手段へのバイアス印加条件として、ＤＣバイアス成分があるとき及びＤＣバイアス成分がないとき、ＡＣバイアスを印加する第１のバイアス印加条件と、バイアス印加無し、ＤＣバイアスのみ印加、前記ＡＣバイアスの、電圧値又は電流値又は周波数を変化させて印加、の３つのうちの少なくと１つの第２のバイアス印加条件と、を備えるｎ種類（ｎ≧２）のバイアス印加条件を持ち、
前記画像形成装置本体は、前記バイアス印加条件ｎにおけるそれぞれの時間ｔ１、ｔ２・・・ｔｎと予め決められた係数ｋ１、ｋ２・・・ｋｎを用いて、前記感光体のダメージ指数Ｄを
Ｄ＝ｋ１×ｔ１＋ｋ２×ｔ２＋・・・＋ｋｎ×ｔｎ
（但し、ｔ１はＡＣバイアス印加時間、ｋ１＞０、ｋ２＞０、ｋ３≧０、・・・、ｋｎ≧０）
の式に基づき演算する手段と、前記感光体のダメージ指数Ｄを感光体ダメージ積算値に積算する積算手段と、該積算手段により積算された積算値と予め定めておいた前記感光体の寿命とする寿命情報とを比較する手段と、該比較手段の結果に基づいて前記積算手段により積算された感光体ダメージ積算値が予め定めておいた前記感光体の寿命とする寿命情報以上であるとき、前記感光体の寿命を警告或いは表示する警告手段或いは報知手段と、が設けられるとともに、
前記プロセスカートリッジは、前記積算値を記憶する記憶手段を有することを特徴とするプロセスカートリッジが提供される。
【００３７】
本発明の他の態様によれば、画像形成装置本体に着脱可能なプロセスカートリッジであって、感光体と、前記感光体を帯電する帯電手段と、を有するプロセスカートリッジにおいて、
前記帯電手段が印加される電圧は、前記感光体が帯電されるときＤＣバイアス成分及びＡＣバイアス成分を含み、前記感光体が除電されるときＤＣバイアス成分なしのＡＣバイアス成分を含み、且つ前記感光体の回転中において、帯電手段へのバイアス印加条件として、ＤＣバイアス成分があるとき及びＤＣバイアス成分がないとき、ＡＣバイアスを印加する第１のバイアス印加条件と、バイアス印加無し、ＤＣバイアスのみ印加、前記ＡＣバイアスの、電圧値又は電流値又は周波数を変化させて印加、の３つのうちの少なくと１つの第２のバイアス印加条件と、を備えるｎ種類（ｎ≧２）のバイアス印加条件を持ち、
前記画像形成装置本体は、前記バイアス印加条件ｎにおけるそれぞれの時間ｔ１、ｔ２・・・ｔｎを積算値Ｓ１、Ｓ２・・・Ｓｎに積算する積算手段と、積算された積算値Ｓ１、Ｓ２・・・Ｓｎと予め決められた係数ｋ１、ｋ２・・・ｋｎを用いて、前記感光体のダメージ指数Ｄを
Ｄ＝ｋ１×Ｓ１＋ｋ２×Ｓ２＋・・・＋ｋｎ×Ｓｎ
（但し、ｔ１はＡＣバイアス印加時間、ｋ１＞０、ｋ２＞０、ｋ３≧０、・・・、ｋｎ≧０である。）
の式に基づき演算する手段と、該演算手段により演算された感光体ダメージ指数と予め定めておいた前記感光体の寿命とする寿命情報とを比較する比較手段と、該比較手段の結果に基づいて前記演算手段により演算された感光体ダメージ指数が予め定めておいた前記感光体の寿命とする寿命情報以上であるとき、前記感光体の寿命を警告或いは表示する警告手段或いは報知手段と、が設けられると共に、
前記プロセスカートリッジは、前記積算値を記憶する記憶手段を有することを特徴とするプロセスカートリッジが提供される。
【００４２】
【発明の実施の形態】
以下、本発明に係る電子写真感光体の寿命検知方法、画像形成装置、及びプロセスカートリッジを図面に即して更に詳しく説明する。
【００４３】
実施例１
本発明の実施例１について、図１〜図４を参照して説明する。図１に、本実施例の画像形成装置である、レーザー光を用いて露光を行うプリンター（ＬＢＰ）が示される。
【００４４】
本実施例のプリンターは、感光ドラムである電子写真感光体１、帯電ローラ２、現像装置７、及びクリーニング装置１４のプロセス手段が組み込まれているプロセスカートリッジ１７、転写ローラ１３、定着装置１５、光学系としてレーザースキャナ４、ミラー６等が配設されている。尚プロセスカートリッジ１７は、装置本体に対して装着ガイド手段８０により交換自在に装着されている。
【００４５】
このプリンターの画像形成工程を以下に示す。
【００４６】
感光体１は、外径が３０ｍｍであり、アルミニウム製の導電性基体１ｂの表面に光導電性の感光層１ａを積層して構成し、図中矢印Ａ方向に１００ｍｍ／ｓｅｃの周速をもって回転駆動される。
【００４７】
又、感光体１は、帯電ローラ２により負極性の均一帯電を受け、次いで、レーザースキャナ４により出力される、ビデオコントローラ（不図示）から送られれる画像情報の時系列電気デジタル画像信号に対応したレーザー露光５により、６００ｄｐｉの解像度をもって走査露光がなされ、画像形成装置本体に設置されているミラー６を介して、表面に静電潜像が形成される。
【００４８】
感光体１の静電潜像は、現像装置７内の現像スリーブ１１上に担持されたトナー８により反転現像され、トナー像として顕像化される。
【００４９】
該トナー像は転写ローラ１３によって転写紙Ｐ上に転写される。そして、トナー像の転写を受けた転写紙Ｐは、感光体１から分離されて搬送手段７０を介して定着装置１５へ導入され、そこでトナー像の定着を受けた後、画像形成装置本体から排出される。転写工程を経た後の感光体１は、残トナーをクリーニング装置１４にてクリーニングされ再度帯電工程に供される。
【００５０】
ところで、現像装置７は、非接触現像方式を採用したものでトナー８を担持してこれを感光体１へと搬送する回動可能に支持されたトナー担持体である現像スリーブ１１と現像スリーブ１１内に固定された磁界発生手段１０と、トナー収容室３とを有している。
【００５１】
現像スリーブ１１は、ＡＣバイアス及びＤＣバイアスが印加できる電源１６と接続されており、本実施例では、ピーク間電圧１２００Ｖの矩形波に−５００ＶのＤＣ成分が供給されると現像スリーブ１１上に薄層に塗布されたトナー８は、感光体１との対向部において感光体１上に現像される。
【００５２】
本実施例において、トナー８は、磁性一成分トナーを使用しており、トナー収容室３に収容されている。
【００５３】
帯電ローラ２は、芯金２ａの上にスポンジ層２ｂと表層２ｃとが巻装された２層構成になっている。芯金２ａは直径６ｍｍ、ローラの外径は１２ｍｍであり、ローラ長は約２２０ｍｍである。また、芯金２ａの両端は、図示矢印ｃの方向にそれぞれ５００ｇｆずつ加圧されており、感光体１に１．５ｍｍ程度のニップをもって接している。
【００５４】
帯電ローラ２は、駆動されておらず、感光体１に対して従動回転する構成とされている。
【００５５】
また、帯電ローラ２は芯金２ａを介して一次バイアス印加電源１２に接続されており、本実施例においては感光体回転中、バイアス印加条件１として画像形成領域を含む一部分でＡＣバイアス（ピーク間電圧１６００Ｖ、周波数１０００Ｈｚ、正弦波）にＤＣバイアス−７００Ｖを重畳したバイアスを印加し、感光体１表面を約−６８０Ｖに均一帯電する。又、感光体回転中その他の部分において、バイアス印加条件２として−１２５０Ｖのみを印加し、感光体１表面を約−６８０Ｖに帯電する部分と、バイアス印加条件３としてバイアスを印加しない部分とが存在する（図３参照）。
【００５６】
ここで本実施例においては、バイアス印加条件１；画像領域において均一な良好画像を得るため、又、プリント終了時に表面電位を除電するためにＡＣバイアスを用いる、バイアス印加条件２；特に均一表面電位は必要としないが現像器からのトナーの不必要な現像の防止、転写部材のクリーニング等のための一定の表面電位が必要であり、感光ドラムのダメージの少ないＤＣバイアスのみを用いる、バイアス印加条件３；特に一定の表面電位を必要としないためバイアスは印加しない、という目的により切り替えられている。
【００５７】
バイアス印加条件２と同じ目的において、ＡＣバイアスの電圧値（又は電流値）を下げる、周波数を落す等の方法もあり、同様に有効である。
【００５８】
次に、本発明の特徴部である電子写真感光体の寿命検知方法について説明する。図３にプリント動作シーケンス、図４に感光体の寿命検知方法に関するフローチャートを示す。
【００５９】
図１において、感光体１は感光体回転指示部２２により回転動作を制御されており、接触帯電部材である帯電ローラ２には、一次バイアス印加電源１２より適宜、ＡＣバイアス、ＤＣバイアスが一次ＡＣ電圧出力指示部２１と一次ＤＣ電圧出力指示部２０により独立に制御され印加される。一次ＡＣ電圧出力指示部２１、一次ＤＣ電圧出力指示部２０及び感光体回転指示部２２はバイアス印加時間検出部２３に連結されており、プリント動作の１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３が検出される。
【００６０】
ここで、図３のプリント動作シーケンスに示すように、ｔ１は一次ＡＣ電圧出力指示部２１からの印加時間情報Ｔａｃ（ｔ１＝Ｔａｃ＝Ｔａｃ１＋Ｔａｃ２）、ｔ２は一次ＤＣ電圧出力指示部２０からの印加時間情報ｔｄｃから一次ＡＣ電圧を重畳している時間Ｔａｃｄｃを引いたもの（ｔ２＝Ｔｄｃ−Ｔａｃｄｃ）、ｔ３は感光体回転指示部２２からの感光体回転時間情報Ｔｄｒからｔ１、ｔ２を引いたもの（ｔ１＝Ｔｄｒ−（ｔ１＋ｔ２））として求められる。
【００６１】
上記のように、バイアス印加時間検出部２３にて各バイアス印加条件での印加時間ｔ１、２ｔ、ｔ３が検出される（ステップ１（Ｓ１））。
【００６２】
プリント動作の１ジョブが終了後、各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３は感光体ダメージ演算部２４に引き渡され、感光体ダメージ指数Ｄが次の式▲１▼により演算される（Ｓ２）。
【００６３】
Ｄ＝ｋ１×ｔ１＋ｋ２×ｔ２＋ｋ３×ｔ３・・・ ▲１▼
上式にて、各係数は、ｋ１＝１、ｋ２＝０．３、ｋ３＝０．１である。
【００６４】
感光体ダメージ積算記憶部２５は記憶している感光体ダメージ積算値Ｓに１ジョブ間の感光体ダメージ指数Ｄを加算して、感光体ダメージ積算値Ｓを更新する（Ｓｎｅｗ＝Ｓｏｌｄ＋Ｄ、Ｓ３）。この作業は、プリント動作の１ジョブ毎に繰り返される。１ジョブが終了し、感光体ダメージ積算記憶部２５に記憶している積算値Ｓの更新が終了すると、比較部２６は、感光体寿命情報記憶部２７から予め設定された寿命情報Ｒを読み込み、更新された感光体ダメージ積算値Ｓとの大小関係を比較する（Ｓ４、Ｓ６）。
【００６５】
その結果、更新された積算値Ｓが寿命情報Ｒよりも大きい場合には警告部（表示部）２８に信号を送り、寿命であることを警告あるいは表示する（Ｓ５）。
【００６６】
ステップ４（Ｓ４）にて、感光体ダメージ積算値Ｓが警告（寿命）情報より小さい場合には、特に警告等を表示せず、通常動作に戻る（Ｓ７）。
【００６７】
図３のシーケンスに示すように、感光体回転時間、一次ＤＣ印加時間、一次ＡＣ印加時間、又は、転写バイアス印加時間はそれぞれ異なっている。
【００６８】
本発明者等が、シーケンス中のそれぞれの状態における感光体１へのダメージ、特にドラム削れに着目して検討した結果、バイアスが印加されていない状態でのドラム削れを１とした場合、一次ＤＣバイアスが印加された状態でのドラム削れは２〜３、一次ＡＣバイアスが印加された状態でのドラム削れは８〜１０と大きな差があることが判明した。この結果は、感光体としてポリカーボ樹脂をメインバインダーとした表層を持つＯＰＣ感光体を用い、感光体クリーニングとしてブレードクリーニングを用いた系にて検討した結果得られた。
【００６９】
以上の検討結果より、感光体１の寿命がドラム削れによって支配的に決定されると考えられると、各バイアス印加条件毎の印加時間にそれぞれ係数をかけ、合計した演算値を積算してドラム削れ量を推測し、寿命を判断することで精度良い寿命検知が可能となる。
【００７０】
従来提案されている方法では、ドラム回転時間とドラム削れ量がほぼ比例するコロナ帯電を用いたものであったので、ドラム回転数あるいはドラム回転時間を積算することで、精度良い寿命検知が可能であったが、上述してきたように、帯電手段として接触帯電を用い、且つＡＣバイアスを印加した系においては、ドラム回転時間とドラム削れ量は比例せず精度良い寿命検知とはならない。
【００７１】
又、転写バイアスを印加している時間を積算することで、ある程度ＡＣ印加している時間を推測することが可能であるが、図３のシーケンスに示すとおり、ＡＣバイアスは画像領域より多めの時間印加されており、又、プリント動作終了時にも印加されているため、ほぼ画像領域にのみ印加されている転写バイアスの印加時間Ｔｔｒとは差があり、この差が寿命検知に対して精度を落してしまうことになる。
【００７２】
本実施例においては、バイアス印加時間検出部２３によりプリント動作の１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３を検出し、感光体ダメージ演算部２４により感光体ダメージ指数Ｄを前出の式▲１▼、及び各係数を用いて演算し、感光体ダメージ積算値Ｓを最新の積算値で更新することにより、感光体１のドラム削れ量を推定し、正確な寿命検知が可能となる。
【００７３】
本実施例においては、接触帯電部材としてスポンジ帯電ローラを用いたが、ソリッドゴムのローラであってもよく、又、ローラ形状に限定されるものでもなく、ブレード形状、ブラシ形状、ブラシローラ等であってもかまわない。
【００７４】
又、本実施例においては、感光体ダメージの演算係数は、
ｋ１＝１、ｋ２＝０．３、ｋ３＝０．１
としたが、感光体材料、バイアス印加条件の組み合わせ、クリーニング方式等により変化するものなので、各系において、最適値を適宜選択すればよい。又、シーケンスにおいて特に感光ドラムの削れに大きく影響を及ぼさない（演算係数ｋｎがｋ１に対して著しく小さい、印加時間ｔｎがｔ１に対して著しく小さい等）バイアス印加条件の項は、必要とされる精度を落さない程度で省略してもよい。
【００７５】
本実施例においては、感光体と帯電ローラ、現像装置、クリーニング装置を一体化したプロセスカートリッジを用いた例について述べているが、感光体単品を消耗品として交換するような画像形成装置においても同様な効果があることは言うまでもない。
【００７６】
実施例２
以下に本発明の実施例２を、図５及び前出の図１に基づいて説明する。
【００７７】
本実施例においては、図１の感光体寿命情報記憶部２７において、感光体寿命を判定するための情報を２段階に設定している。即ち、ユーザに感光体寿命が近づいたので、交換の準備をするように促すことを指示するための警告情報Ｙと、真の感光体寿命である寿命情報Ｒとの２段階に設定している。当然ながら、警告情報Ｙ＜感光体寿命Ｒなる関係である。
【００７８】
図１において、感光体１は感光体回転指示部２５により回転動作を制御されており、接触帯電部材である帯電ローラ２には、一次バイアス印加電源１２より適宜ＡＣバイアス、ＤＣバイアスが一次ＡＣ電圧出力指示部２１と一次ＤＣ出力指示部２０により独立して制御され印加される。
【００７９】
一次ＡＣ電圧出力指示部２１、一次ＤＣ電圧出力指示部２０、及び感光体回転指示部２２はバイアス印加時間検出部２３に連結されており、プリント動作の１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３が検出される（Ｓ１１）。
【００８０】
プリント動作の１ジョブが終了後、各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３は感光体ダメージ演算部２４に引き渡され、感光体ダメージ指数Ｄが実施例１にて示した次の式▲１▼、
Ｄ＝ｋ１×ｔ１＋ｋ２×ｔ２＋ｋ３×ｔ３・・・ ▲１▼
（上式にて、各係数は、ｋ１＝、ｋ２＝０．３、ｋ３＝０．１である。）
により演算される。
【００８１】
感光体ダメージ積算記憶部２５は記憶している感光体ダメージ積算値Ｓに１ジョブ間の感光体ダメージ指数Ｄを加算して、感光体ダメージ積算値Ｓを更新する（Ｓｎｅｗ＝Ｓｏｌｄ＋Ｄ、Ｓ１３）。
【００８２】
この作業は、プリント動作の１ジョブ毎に繰り返される。１ジョブが終了し、感光体ダメージ積算記憶部２５に記憶している積算値Ｓの更新が終了すると、比較部２６は、感光体寿命記憶部２７から予め設定された警告情報Ｙ及び寿命情報Ｒを読み込み（Ｓ１６）、感光体ダメージ積算記憶部２５からは、更新された積算値Ｓを読み込む。
【００８３】
先ず、積算値Ｓと警告情報Ｙとを比較し（Ｓ１４）、その結果、更新された積算値Ｓが警告情報Ｙより小さい場合は、通常のプリントシーケンスに戻し、感光体１の寿命情報は表示しない（Ｓ１７）。
【００８４】
積算値Ｓと警告情報Ｙとを比較した結果が、Ｓ≧Ｙであれば、積算値Ｓと寿命情報Ｒとを比較する（Ｓ１５）。Ｓ＜Ｒであれば、警告部（表示部）にユーザに感光体寿命が近づいたので、通常動作は継続しつつ交換の準備をするように促すように指示する（Ｓ１８）。
【００８５】
Ｓ≧Ｒであれば、感光体寿命警告部（表示部）２８にユーザに感光体の寿命であることを伝え、感光体の交換をするように促すように指示すると共にプリント動作を阻止する（Ｓ１９）。感光体１が新しく交換されたことが確認されたら、再びプリント動作を許可する。
【００８６】
本実施例においては、感光体寿命を判定するための情報を警告情報と寿命情報の２段階に設定しているが、それ以上細かく設定して、詳細な感光体の寿命情報をユーザに提示してもよいことは言うまでもない。
【００８７】
上記により、ユーザーが感光体の寿命が近くなって交換する時期が近いことを感知できて、予め新しい感光体を準備して寿命になったときに直ちに交換でき、又、感光体が寿命になったときには、装置を停止するので、寿命になった後にプリントを行なうことによる本体のダメージを防止することができる。
【００８８】
実施例３
以下に、本発明の実施例３を図６及び図７に基づいて説明する。画像形成装置の概略構成は、実施例１と同様であるので、変更点のみについて説明する。
【００８９】
実施例１においては、プロセスカートリッジは、電子写真感光体１、帯電ローラ２、現像装置３、及びクリーニング装置１４を一体化したものであったが、本実施例においては、電子写真感光体１、帯電ローラ２、及びクリーニング装置を一体化したドラムユニット（プロセスカートリッジ）２９を一体化し、装置本体に対して装着ガイド手段８０により交換自在とされており、現像装置７は別ユニットとしている。ドラムユニット２９内には、記憶手段である記憶素子３０を搭載し、又、ドラムユニット２９の容器には、画像形成装置に装着された際に本体の制御部と通信可能なように接続端子（不図示）が設けられている。
【００９０】
画像形成工程は、実施例１と同じであるので省略する。
【００９１】
図６においては、感光体１は感光体回転指示部２２により回転動作を制御されており、接触帯電部材である帯電ローラ２には、一次バイアス印加電源１２より適宜ＡＣバイアス、ＤＣバイアスが一次ＡＣ電圧出力指示部２１と一次ＤＣ電圧出力指示部２０により独立に制御され印加される。
【００９２】
一次ＡＣ電圧出力指示部２１、一次ＤＣ電圧出力指示部２０及び感光体回転指示部２２はバイアス印加時間検出部２３に連結されており、プリント動作の１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３が検出される（Ｓ２１）。
【００９３】
プリント動作の１ジョブが終了後、各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３は感光体ダメージ演算部２４に引き渡され、感光体ダメージ指数Ｄが次の式▲１▼、
Ｄ＝ｋ１×ｔ１＋ｋ２×ｔ２＋ｋ３×ｔ３・・・ ▲１▼
（ここで、上記各係数は、ｋ１＝、ｋ２＝０．３、ｋ３＝０．１である。）
により演算される。
【００９４】
又、感光体ダメージ演算部２４はドラムユニット２９内の記憶素子３０に連結されており、１ジョブ毎に記憶素子３０から感光体ダメージ積算値Ｓを読み込んで感光体ダメージ積算値Ｓを更新する（Ｓ２２）。
【００９５】
この作業は、プリント動作の１ジョブが終了し、ドラムユニット２９の記憶素子３０に記憶している積算値Ｓの更新が終了すると（Ｓ２３）、比較部２６は、ドラムユニット２９の記憶素子３０から、更新された積算値Ｓ及び予め設定され記憶されている寿命情報Ｒを読み込み、両者の大小関係を比較する（Ｓ２４）。その結果、更新された積算値Ｓが寿命情報Ｒよりも大きい場合（Ｓ≧Ｒ）には警告部（表示部）２８に信号を送り寿命であることを警告あるいは表示し、本体のプリント行為を禁止する（Ｓ２５）。
【００９６】
積算値Ｓが寿命情報Ｒより小さい場合（Ｓ＜Ｒ）には、特に警告表示をせず通常動作に戻る（Ｓ２６）。
【００９７】
本実施例では、ドラムユニット２９に記憶素子３０を設けたことにより、ユニット毎に記憶されている感光体ダメージ指数が異なるので、ユニットの判別が容易にできる。即ち、新品のユニットに交換した際、誤ってユーザが古いユニットを装着しても、特別に識別手段を設けることなく判断できるので、ユーザの交換ミスを防止でき、誤って寿命を越えたドラムユニットを使用し、不良画像を出力するなどの不具合を防止できる。
【００９８】
又、感光ドラムの寿命に関する情報Ｒをドラムユニット２９の記憶素子３０に予め記憶させることにより、寿命の異なるドラムユニットを装着した場合においてもそれぞれの寿命に応じて、適切に寿命を検知し警告等を行うことができる。
【００９９】
実施例４
次に、本発明の実施例４について図８及び図９により説明する。画像形成装置の概略構成は、実施例１と同じであるので、変更点のみについて説明する。
【０１００】
本実施例は、実施例３と同様に、電子写真感光体１、帯電ローラ２、及びクリーニング装置１４を一体化してドラムユニット（プロセスカートリッジ）２９とし、現像装置７は別ユニットとし、ドラムユニット２９内には、記憶素子３０を搭載した例である。又、ドラムユニット２９の容器には、画像形成装置本体に装着された際に本体の制御部と通信可能なように接続端子（不図示）が設けられていることも同様である。
【０１０１】
本実施例の特徴部は、実施例１〜３の感光体の寿命検知方法が、プリント動作の１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３を検知し、感光体ダメージ演算部により感光体ダメージ指数を演算した後、本体の感光体ダメージ積算記憶部又はドラムユニットの記憶素子に感光体ダメージ積算値を記憶していたのに対し、各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３そのものを各積算値Ｓ１、Ｓ２、Ｓ３に積算記憶し、任意のタイミングにおいて積算値Ｓ１、Ｓ２、Ｓ３を読み出し、感光体ダメージ演算部において係数ｋ１、ｋ２、ｋ３を用いてトータルの感光体ダメージ指数Ｄを式▲２▼、
Ｄ＝ｋ１×Ｓ１＋ｋ２×Ｓ２＋ｋ３×Ｓ３・・・ ▲２▼
により求める点、更には、係数ｋ１、ｋ２、ｋ３の値を、各バイアス印加条件の印加時間の積算値Ｓ１、Ｓ２、Ｓ３の比率により可変とする点である。
【０１０２】
図８及び図９のフローチャートに基づき、本発明の特徴部分である感光体の寿命検知方法について説明する。
【０１０３】
図８において、感光体１は感光体回転指示部２２により回転動作を制御されており、接触帯電部材である帯電ローラ２には、一次バイアス印加電源１２より適宜ＡＣバイアス、ＤＣバイアスが一次ＡＣ電圧出力指示部２１と一次ＤＣ電圧出力指示部２０により独立に制御され印加される。
【０１０４】
一次ＡＣ電圧出力指示部２１、一次ＤＣ出力指示部２０及び感光体回転指示部２２はバイアス印加時間検出部２３に連結されており、プリント動作の１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３が検出される（Ｓ３１）。
【０１０５】
プリント動作の１ジョブが終了後、各バイアス印加条件の印加条件ｔ１、ｔ２、ｔ３は感光体ダメージ演算部２４に引き渡され、感光体ダメージ演算部２４は連結されているドラムユニット２９内の記憶素子３０から、記憶している感光体各バイアス印加条件の印加時間の積算値Ｓ１、Ｓ２、Ｓ３を読み込み、その値に１ジョブ間の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３を加算して、記憶素子３０に記憶している各バイアス印加条件の印加時間の積算値Ｓ１、Ｓ２、Ｓ３を更新する（Ｓ３２、Ｓ３３）。
【０１０６】
その後、更新された各バイアス印加条件の印加時間の積算値Ｓ１、Ｓ２、Ｓ３を用いて、感光体ダメージ指数Ｄが式▲２▼、
Ｄ＝ｋ１×Ｓ１＋ｋ２×Ｓ２＋ｋ３×Ｓ３・・・ ▲２▼
により演算される（Ｓ３４）。
【０１０７】
このとき係数ｋ１、ｋ２、ｋ３の値は各バイアス印加条件の印加時間の積算値Ｓ１、Ｓ２、Ｓ３の比率によって適宜調整される。本実施例では、感光体ドラム削れに対する影響度の最も大きいバイアス印加条件１（正弦波、周波数１０００Ｈｚ、ピーク間電圧１６００ＶのＡＣバイアスにＤＣバイアス−７００Ｖを重畳したバイアス）の印加時間の積算値Ｓ１に注目し、感光ドラム回転時間（Ｓ１＋Ｓ２＋Ｓ３）に対するバイアス印加時間条件１の印加時間積算値Ｓ１の割合ρを演算し、割合ρにより、
ｋ１＝１、ｋ２＝０．５×ρ、ｋ３＝０．２×ρ
としている。
【０１０８】
感光体ダメージ指数の演算が終了すると、比較部２６は、ドラムユニット２９の記憶素子３０から、予め設定され記憶されている寿命情報Ｒを読み込み、演算された感光体ダメージ指数Ｄと大小関係を比較する（Ｓ３５）。
【０１０９】
その結果、演算された感光体ダメージ指数Ｄが寿命情報Ｒより大きい場合（Ｄ≧Ｒ）には警告部（表示部）２８に信号を送り寿命であることを警告あるいは表示する（Ｓ３６）。
【０１１０】
感光体ダメージ指数Ｄが寿命情報Ｒより小さい場合には、特に警告等の表示をせず、通常動作に戻る（Ｓ３７）。
【０１１１】
本実施例のようにバイアス印加条件１の印加時間積算値Ｓ１の感光ドラム回転時間（Ｓ１＋Ｓ２＋Ｓ３）に対する割合により、バイアス印加条件２、３の印加時間積算値Ｓ２、Ｓ３に関する係数ｋ２、ｋ３を変化させた理由は、次のような実験結果に基づいている。
【０１１２】
即ち、実施例１にて述べたように、ＡＣバイアス印加、ＤＣバイアス印加のみの印加、バイアス印加無し等のバイアス印加条件の違いにより感光ドラムのダメージ（主に削れ量）に違いがある。特に、ＡＣバイアス印加時の感光ドラムの削れ量は、その他の場合に比べ多くなることが実験により確認された。
【０１１３】
更に本発明者等は、感光ドラムの回転時間中のＡＣバイアスの印加時間の程度により、それ以外のバイアス印加条件時の感光ドラムの削れ量にも影響があると考え、感光ドラムの回転時間中のＡＣバイアスの印加時間割合を５０％→７０％と変えて単位時間当りの感光ドラムの削れ量を測定する実験をした。
【０１１４】
その結果、ＡＣバイアスの印加時間割合が大きい程、その他のバイアス印加条件時の感光ドラムの削れ量を１としてＤＣバイアスのみの印加時で０．２０→０．４程度、バイアス印加無し時において０．１→０．１５程度と増加していることが判明した。この実験も実施例１同様に、感光体１としてポリカーボ樹脂をメインバインダーとした表層を持つＯＰＣ感光体を用い、感光体クリーニングとしてブレードクリーニングを用いた系にて行った。
【０１１５】
以上の結果に基づき、本実施例において感光ドラムのダメージ指数の演算係数ｋ１、ｋ２、ｋ３を、感光ドラム回転時間（Ｓ１＋Ｓ２＋Ｓ３）に対するバイアス印加条件１の印加時間積算値Ｓ１の割合ρにより簡易的に
ｋ１＝１、ｋ２＝０．５×ρ、ｋ３＝０．２×ρ
と設定した。
【０１１６】
感光ドラムの寿命が短い（例えば通紙可能枚数１万枚程度）場合、実施例１〜３のように感光ドラムのダメージ指数の演算係数ｋ１、ｋ２、ｋ３を定数としても従来方式に対し、十分精度を上げることができるが、感光ドラムの寿命が長い（例えば通紙可能枚数５万枚程度）場合、耐久枚数の増加に比例して誤差も大きくなるため本実施例のように演算係数を変化させた方がより精度を上げることができる。
【０１１７】
本実施例のように、ドラムユニット２９に記憶素子３０を設け、各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３そのものを各積算値Ｓ１、Ｓ２、Ｓ３に積算して記憶素子３０に記憶し、任意のタイミングにおいて積算値Ｓ１、Ｓ２、Ｓ３を読み出し、感光体ダメージ演算部２４において積算値Ｓ１、Ｓ２、Ｓ３の比率により決まる係数ｋ１、ｋ２、ｋ３を用いてトータルの感光体ダメージ指数Ｄを求める方式を用いることにより、感光体の寿命を精度よく推測することができる。
【０１１８】
その上、使用後のドラムユニット２９を回収することにより実際の市場の使用状況に関する情報を多く収集することができ、そのデータに基づき演算係数を微調整する等を行い、更なる高精度化を図ることができる。
【０１１９】
但し、感光体の寿命を精度良く推測するという目的に関しては、各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３の積算値Ｓ１、Ｓ２、Ｓ３は画像形成装置本体に記憶してもよく、又、実施例１〜３のように１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３を検知し、感光体ダメージ演算部により感光体ダメージ指数を演算した後、本体の感光体ダメージ積算記憶部又はドラムユニットの記憶素子に感光体ダメージ積算値を記憶する方式において、１ジョブ毎に感光体ダメージ指数を演算する際に、１ジョブ中の各バイアス印加条件の印加時間ｔ１、ｔ２、ｔ３の比率から係数ｋ１、ｋ２、ｋ３を変化させ、１ジョブでの感光体ダメージ指数を求めても、同様に効果がある。
【０１２０】
また、本実施例においては、感光体ダメージの演算係数の簡易的な式により、係数を、ｋ１＝１、ｋ２＝０．５×ρ、ｋ３＝０．２×ρ
としたが、感光体材料、バイアス印加条件の組み合わせ、クリーニング方式等により変化するものなので、各系において最適値及び可変方法を適宜選択すればよい。
【０１２１】
更に、環境変動、耐久変動等による帯電部材の抵抗変動、感光ドラム削れによる感光ドラムの容量変動により、ＡＣバイアスの電圧値、電流値を変化し、感光ドラムが受けるダメージ量も変化するような場合、ＡＣバイアスの電圧値又は電流値を検知する手段を設け、それによりＡＣバイアス印加時の演算係数を変化させる方法も効果的である。
【０１２２】
実施例５
実施例１〜４においては、図１、図６、図８にそれぞれ示したモノカラーレーザビームプリンタに本発明を適用した場合について説明したが、実施例５においては、本発明を図１０及び図１１に示す、イエロー、マゼンタ、シアン、ブラックのフルカラーレーザビームプリンタに適用する。
【０１２３】
図１０において、感光ドラム７１は、不図示の駆動手段によって図時矢印方向に駆動され、ローラー帯電器７２により所定の電位に均一に帯電される。次いで、イエローの画像模様に従った信号が入力された露光装置７３により、レーザ光が感光ドラム７１に照射され、感光ドラム７１上に潜像が形成される。
【０１２４】
更に感光ドラム７１が矢印方向に進むと支持体７５に支持された現像装置７４ａ、７４ｂ、７４ｃ、７４ｄのうち、例えばイエロートナーが収容された現像装置７４ａが感光ドラム７１に対向するように支持体５が回転され、上記の潜像は現像装置７４ａによって可視化される。次いで、現像されたトナー像は中間転写体である中間転写ベルト６６上に転写される。
【０１２５】
中間転写ベルト６６は３本の支持ローラー６１、６２、６３上に張設され、不図示の駆動源に連結された支持ローラー６２が回転することにより、図中矢印方向に移動する。又、中間転写ベルト６６の内側の感光ドラム対向部には、一次転写ローラ６４が設けられ、不図示の高圧電源から所定のバイアスが印加され、感光ドラム７１上のトナーは中間転写ベルト６６上に転写される。
【０１２６】
以上の工程を更に例えばマゼンタ、シアン、黒の順に現像装置７４ｂ、７４ｃ、７４ｄにより実施することによって中間転写ベルト６６上に４色のトナー像が形成される。
【０１２７】
この４色のトナー像は、中間転写ベルト６６の移動と同期をとって給紙装置７６から搬送手段７７を介して搬送された転写紙上に、２次転写ローラー６５により一括転写される。更に、転写紙は、加熱・加圧定着装置７８によって溶融固着されカラー画像が得られる。
【０１２８】
感光ドラム７１上の転写残トナーはブレード手段を備えたクリーニング装置７９によって清掃される。
【０１２９】
又、本実施例においては、帯電ローラー７２、感光ドラム７１、及びクリーニング装置７９が一体のプロセスカートリッジ９０として、図１１に示すような外観を有するように構成され、装置本体に対して装着ガイド手段８０により脱着自在とされている。更に、上記の実施例のカートリッジメモリ部４と同様に機能する記憶手段８４を備えている。
【０１３０】
尚、４色の各現像器７４ａ〜７４ｄもプロセスカートリッジと同様に、装置本体と脱着可能な構成とされている。これらの構成により、従来サービスマンが行なっていた上記部材の交換、メンテナンスをユーザが簡単に行なうことができる。
【０１３１】
上記のような構成のフルカラー画像形成装置に、実施例１、２、３及び４にて説明した本発明を適用することにより、上記と同様の作用効果を得ることができる。
【０１３２】
【発明の効果】
以上の説明から明らかなように、本発明によれば、電子写真感光体の正確な寿命検知を行なうことができ、装置本体の作動を停止できることにより、寿命後のプリントによる本体ダメージを防止でき、又、電子写真感光体の寿命による交換時期が近いことを正確に検知できる電子写真感光体の寿命検知方法、この寿命検知方法を用いた画像形成装置及びプロセスカートリッジ、このプロセスカートリッジを備えた画像形成装置を得ることができる。
【図面の簡単な説明】
【図１】実施例１の画像形成装置を示す概略構成図である。
【図２】図１の画像形成装置に装着されるプロセスカートリッジを示す構成図である。
【図３】実施例１の画像形成のタイミングチャートを示す図である。
【図４】実施例１の寿命検知のフローチャートである。
【図５】実施例２の画像形成装置の寿命検知のフローチャートである。
【図６】実施例３の画像形成装置を示す概略構成図である。
【図７】実施例３の画像形成装置の寿命検知フローチャートである。
【図８】実施例４の画像形成装置を示す概略構成図である。
【図９】実施例４の画像形成装置の寿命検知フローチャートである。
【図１０】実施例５の画像形成装置を示す概略構成図である。
【図１１】実施例５の画像形成装置に装着されたプロセスカートリッジの外観図である。
【符号の説明】
１感光ドラム（電子写真感光体）
２帯電ローラ（帯電手段）
７、７５現像装置（現像手段）
１０現像スリーブ
１４クリーニング手段
１７、２９、９０プロセスカートリッジ
２３バイアス印加時間検出部（検出手段）
２４感光体ダメージ演算部（演算手段）
２５感光体ダメージ積算記憶部（積算手段）
２６比較部（比較手段）
２８警告部（表示部・警告手段・報知手段）
３０、８４記憶素子（記憶手段）
７０、７７搬送手段
８０装着手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photoconductor life detecting method used in an electrophotographic image forming apparatus, an image forming apparatus using the photoconductor life method, a process cartridge used in the image forming apparatus, and an electrophotographic image in which the process cartridge is detachable. It relates to a forming apparatus.
[0002]
Here, examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, and the like), an electrophotographic facsimile machine, an electrophotographic word processor, and the like.
[0003]
The process cartridge is a unit in which a charging unit, a developing unit, or a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is detachable from the main body of the electrophotographic image forming apparatus. Means, a developing means, a cleaning means and an electrophotographic photosensitive member are integrally made into a cartridge so as to be detachable from an electrophotographic image forming apparatus main body, or at least a developing means and an electrophotographic photosensitive member are It refers to an integrated cartridge that can be attached to and detached from the main body of the electrophotographic image forming apparatus.
[0004]
[Prior art]
Conventionally, in an electrophotographic image forming apparatus, the following methods have been used to detect the life of an electrophotographic photosensitive member (generally, a photosensitive drum is often used).
[0005]
Conventional example 1: Method of integrating the number of prints (copies)
The simplest method has the drawback that even if the print (copy) size is different, for example, A4 size and A3 size are counted as the same one, so the accuracy of life detection is not good. Was. Further, the accuracy of life detection is not good because the drum rotation time per sheet varies depending on how many sheets are printed per job.
[0006]
Conventional example 2: A method of detecting the charge amount with a surface potential sensor
This method is disclosed in Japanese Patent Application Laid-Open No. 4-51259. Actually, a decrease in the charged potential of the photosensitive drum or a decrease in the contrast of the latent image can be directly detected by the surface potential sensor, so that the life can be detected more accurately by reflecting the state of the output image as compared with the first conventional example.
[0007]
However, a surface potential sensor, an electric circuit for processing its output, and the like are required, which increases costs. In the longitudinal direction, only information on the drum corresponding to the sensor position can be determined, so it is vulnerable to partial failure, and it is not always accurate in consideration of instability such as sensor variation and aging. It cannot be said that it is a life detection method.
[0008]
As a method of solving the problem of the above-described conventional example 1 and increasing the detection accuracy, there is the following method.
[0009]
Japanese Patent Application Laid-Open No. Hei 5-188677 discloses a method of integrating the number of rotations of a photosensitive drum instead of integrating the number of prints (copies). There is also a method of integrating the rotation time of the photosensitive drum with the same contents. In both cases, as compared with the case of integrating the number of prints, the number of rotations increases when the paper size is large, and the number of rotations decreases when the paper size is small. An error in life detection due to a difference in size is reduced. In addition, since the number of rotations (rotation time) of the drum is directly integrated irrespective of the number of prints per job, there is a merit that the accuracy of life detection is good.
[0010]
There are also methods that have further developed this method. That is, in Japanese Patent Application Laid-Open No. 4-98265, the drum rotation speed during actual image formation is integrated by integrating the drum rotation speed only when the transfer charger is operated. It is disclosed that more accurate life detection is possible.
[0011]
According to Japanese Patent Application Laid-Open No. Hei 6-180518, the number of rotations of the drum while charging is performed and the number of rotations of the drum while the cleaning member is in contact with each other are integrated, and each set value (lifetime) is calculated. ) Is disclosed for determining the life.
[0012]
On the other hand, there is the following method for notifying the user of the replacement timing of the process cartridge in advance.
[0013]
According to JP-A-5-333626, first, a process cartridge is composed of a cleaner and an image carrier, and a storage element is provided in this process cartridge. In addition, the replacement display operation based on the life of the image carrier is to add up the number of prints and stop the apparatus to make it unusable when the guaranteed life of the image carrier comes. In the meantime, a message is displayed to indicate that the replacement time is running short and to prompt the user to prepare, and to display that the time to stop the apparatus when the device is to be used further is approaching.
[0014]
In addition, the replacement display operation based on the capacity in the toner storage unit accumulates the ON time of the drive motor for toner replenishment, and stops the device at the accumulated time that seems to come first under the worst conditions taking into account various variations Let it. In this case as well, a display prompting replacement with a certain value of the integration time until the device is stopped, and a display prompting that the time to stop the device with a further advanced integration time is approaching. In addition, the operation based on the life of the image carrier and the operation based on the capacity of the toner storage unit are usually set so that the number of prints is prioritized. The latter operation is intended to be performed when the image carrier is likely to be filled earlier than the guaranteed number of images.
[0015]
In addition, when the process cartridge is replaced, the total energizing time of the primary charger of the image forming apparatus is collectively written into the storage element by the CPU provided in the image forming apparatus, and the total time of the subsequent primary charger is written and saved. By collecting and analyzing the storage elements of the used process cartridge, the rotation speed of the image carrier (photosensitive drum) and the corotron of the current image forming apparatus using the used process cartridge are collected. It is described that the total amount such as the discharge time can be accurately grasped, and information can be collected for the image forming apparatus at intervals of replacing the process cartridge.
[0016]
Specifically, the number of operation cycles of the image carrier of the image forming apparatus at the time of replacing the process cartridge, the replacement time of the ozone filter, the wear data prediction of the image carrier, and the like can be grasped. However, since the life determination of the image carrier in this publication is based solely on the number of prints, the accuracy of the life prediction is not good as described above.
[0017]
[Problems to be solved by the invention]
In recent years, as a primary charging device, a contact charging device has been widely used instead of a conventionally used corona charging device. The contact charging device has a great advantage in that it requires a lower applied bias compared to the conventional corona charging device, generates very little ozone, requires fewer components constituting the charging device, and can be provided at low cost. .
[0018]
The contact charging device is roughly classified into a brush charging device and a roller charging device depending on the shape of the member used. The brush charging device has a problem with brush brushes, falling down of hair when the brush is in contact with the photoconductor for a long time, and the like.
[0019]
On the other hand, in the roller charging device, it is necessary to adjust the resistance of the roller to obtain uniform charging, to prevent drum contamination from bleeding from rubber constituting the roller, and to obtain uniform charging. There are difficult problems such as severe restrictions on the shape and surface properties of the roller.
[0020]
Further, the voltage applied to the charging member includes a voltage to which only a DC bias is applied (hereinafter, referred to as DC charging) and a voltage in which an AC bias is superimposed on the DC bias (hereinafter, referred to as AC charging). Generally, AC charging has a feature that uniform charging is possible as compared with DC charging.
[0021]
Further, in the AC charging, a roller is used as a charging member, and a DC voltage is superimposed on an AC bias having an applied bias of twice or more of a discharge starting voltage (JP-A-63-149669 and JP-A-1-267667). ), And a device in which a conductive brush is used as a charging member and a DC voltage is superimposed on an AC voltage having an applied bias of twice or less of a discharge starting voltage (Japanese Patent Laid-Open No. 6-130732).
[0022]
The advantages of contact charging are that the amount of ozone generated is small, that the number of parts constituting the charging device is small, and that it can be provided at low cost. The tendency is remarkable in the drum.
[0023]
Further, even with the same contact charging method, the damage to the photosensitive drum depends on the applied voltage, and the larger the applied voltage, the greater the damage. Even when only the DC voltage is applied, the damage is larger than when the OPC drum is rotated without applying the bias. It has been found that when the AC voltage is applied, the damage (particularly, the amount of scraping of the OPC drum) is several times larger than when only the DC voltage is applied.
[0024]
In particular, this phenomenon is remarkable when an AC voltage that is twice or more the discharge starting voltage is applied. However, even when the AC voltage is twice or less the discharge starting voltage, damage that is several times as large as that of only the DC voltage is still caused. is there.
[0025]
Also, when the frequency of the AC voltage is increased, the damage of the OPC drum tends to increase.
[0026]
Accordingly, when an attempt is made to detect the life of a photosensitive drum in an image forming apparatus using contact charging with a plurality of charging conditions during image formation using both an AC voltage and a DC voltage as charging means, a conventional drum is used. With the life detection method using the number of rotations, it is difficult to accurately predict the life of the photosensitive drum, and no warning is issued even if the life has expired and an image defect has occurred, or a warning has been issued when the life has not yet come. There is a risk that inconveniences may occur.
[0027]
Accordingly, a main object of the present invention is to provide a photoconductor life detecting method for accurately detecting the life of a photoconductor, an image forming apparatus using the detecting method, a process cartridge mounted on the image forming apparatus, and a process cartridge. An object of the present invention is to provide an image forming apparatus provided with a process cartridge.
[0028]
Another object of the present invention is to provide a photoconductor life detecting method for accurately detecting that a replacement time due to the life of an electrophotographic photoconductor is near, an image forming apparatus using the detection method, and a photoreceptor mounted on the image forming apparatus. And an image forming apparatus provided with the process cartridge.
[0029]
[Means for Solving the Problems]
The above object is achieved by a method for detecting the life of an electrophotographic photosensitive member according to the present invention, an image forming apparatus and a process cartridge using the method, and an image forming apparatus including the process cartridge. In summary, the present invention relates to a method for detecting the life of a photoconductor of an image forming apparatus for forming an image on a recording medium,
The voltage applied to the charging unit for charging the photoconductor includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged. The DC bias component and the absence of the DC bias component as the bias application conditions to the charging unit during the rotation of the photoconductor. , Apply AC bias First At least one of the following three conditions: bias application condition, no bias application, only DC bias application, and the AC bias applied by changing the voltage value or current value or frequency. Second Bias application conditions, Have It has n kinds (n ≧ 2) of bias application conditions,
The image forming apparatus main body calculates the damage index D of the photoreceptor using the respective times t1, t2... Tn under the bias application condition n and predetermined coefficients k1, k2.
D = k1 × t1 + k2 × t2 +... + Kn × tn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
The damage index D of the photoreceptor is integrated with the integrated value of the photoreceptor damage, and the integrated value is compared with a predetermined lifetime information of the photoreceptor, and When the integrated photoconductor damage integrated value is equal to or longer than a predetermined integrated time as the photoconductor life based on the comparison result, the life of the photoconductor is warned or displayed. This is a method for detecting the life of the body.
[0031]
According to another aspect of the present invention, there is provided a method for detecting the life of a photosensitive member of an image forming apparatus for forming an image on a recording medium,
The voltage applied to the charging unit for charging the photoconductor includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged. The DC bias component and the absence of the DC bias component as the bias application conditions to the charging unit during the rotation of the photoconductor. , Apply AC bias First At least one of the following three conditions: bias application conditions, no bias application, only DC bias application, and application of the AC bias by changing the voltage value or current value or frequency. Second Bias application conditions, Have It has n kinds (n ≧ 2) of bias application conditions,
The image forming apparatus main body integrates the respective times t1, t2... Tn under the bias application condition n into integrated values S1, S2... Sn, and obtains the integrated values S1, S2. Using predetermined coefficients k1, k2,... Kn, the damage index D of the photoreceptor is calculated.
D = k1 × S1 + k2 × S2 +... + Kn × Sn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
The damage index D is compared with a predetermined life information R which is a predetermined life of the photoconductor, and the damage index D is determined based on the comparison result. The life of the photoconductor is warned or displayed when the life of the photoconductor is equal to or longer than the integrated time.
[0033]
According to another aspect of the present invention, in an image forming apparatus for forming an image on a recording medium,
A charging unit for charging the photoconductor, wherein the voltage applied to the charging unit includes a DC bias component and an AC bias component when the photoconductor is charged, and a DC bias component when the photoconductor is discharged. When the DC bias component is included and the DC bias component is not included as the bias application condition to the charging unit during the rotation of the photoconductor, the AC bias component is included. , Apply AC bias First At least one of the following three conditions: bias application conditions, no bias application, only DC bias application, and application of the AC bias by changing the voltage value or current value or frequency. Second Bias application conditions, Have The image forming apparatus main body has n types (n ≧ 2) of bias application conditions, and the main body of the image forming apparatus described above has respective times t1, t2... tn under the bias application conditions n and predetermined coefficients k1, k2. The damage index D of the photoreceptor is calculated using kn
D = k1 × t1 + k2 × t2 +... + Kn × tn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
Means for calculating the damage index D of the photoreceptor to an integrated value of the photoreceptor damage, and a life of the photoreceptor predetermined by the integrated value integrated by the integrating means. Means for comparing the life information to be performed, and when the photosensitive member damage integrated value integrated by the integrating means based on the result of the comparing means is equal to or longer than the predetermined life information for the life of the photosensitive member, An image forming apparatus comprising: a warning unit or a notification unit that warns or displays the life of the photoconductor, and a conveyance unit that conveys the recording medium.
[0034]
According to another aspect of the present invention, in an image forming apparatus for forming an image on a recording medium,
A charging unit for charging the photoconductor, wherein the voltage applied to the charging unit includes a DC bias component and an AC bias component when the photoconductor is charged, and a DC bias component when the photoconductor is discharged. When the DC bias component is included and the DC bias component is not included as the bias application condition to the charging unit during the rotation of the photoconductor, the AC bias component including no component is included. , Apply AC bias First At least one of the following three conditions: bias application conditions, no bias application, only DC bias application, and application of the AC bias by changing the voltage value or current value or frequency. Second Bias application conditions, Have It has n kinds (n ≧ 2) of bias application conditions,
The image forming apparatus main body includes integrating means for integrating the respective times t1, t2... Tn under the bias application condition n into integrated values S1, S2... Sn, and integrated integrated values S1, S2. Using the Sn and predetermined coefficients k1, k2,.
D = k1 × S1 + k2 × S2 +... + Kn × Sn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
Means for calculating based on the following formula; comparing means for comparing the photoreceptor damage index D calculated by the calculating means with predetermined life information as the life of the photoreceptor; When the photoconductor damage index calculated by the calculation unit based on the life information is a predetermined life of the photoconductor or longer, a warning unit or a notification unit that warns or displays the life of the photoconductor, Conveying means for conveying the recording medium,
An image forming apparatus characterized by having:
[0036]
According to another aspect of the present invention, there is provided a process cartridge detachably mountable to an image forming apparatus main body, the process cartridge including: a photosensitive member; and a charging unit configured to charge the photosensitive member.
The voltage applied to the charging means includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged, and During the rotation of the body, when there is a DC bias component and when there is no DC bias component, , Apply AC bias First At least one of the following three conditions: bias application conditions, no bias application, only DC bias application, and application of the AC bias by changing the voltage value or current value or frequency. Second Bias application conditions, Have It has n kinds (n ≧ 2) of bias application conditions,
The image forming apparatus main body calculates the damage index D of the photoreceptor using the respective times t1, t2... Tn under the bias application condition n and predetermined coefficients k1, k2.
D = k1 × t1 + k2 × t2 +... + Kn × tn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
Means for calculating the damage index D of the photoreceptor to an integrated value of the photoreceptor damage, and a life of the photoreceptor which is predetermined by the integrated value integrated by the integration means. Means for comparing the life information to be performed, and when the photosensitive member damage integrated value integrated by the integrating means based on the result of the comparing means is equal to or longer than the life information to be a predetermined life of the photosensitive member, A warning means or a notification means for warning or displaying the life of the photoconductor, and
The process cartridge includes a storage unit that stores the integrated value.
[0037]
According to another aspect of the present invention, there is provided a process cartridge detachably mountable to an image forming apparatus main body, the process cartridge including: a photosensitive member; and a charging unit configured to charge the photosensitive member.
The voltage applied to the charging means includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged, and During the rotation of the body, when there is a DC bias component and when there is no DC bias component, , Apply AC bias First At least one of the following three conditions: bias application conditions, no bias application, only DC bias application, and application of the AC bias by changing the voltage value or current value or frequency. Second Bias application conditions, Have It has n kinds (n ≧ 2) of bias application conditions,
The image forming apparatus main body includes integrating means for integrating the respective times t1, t2... Tn under the bias application condition n into integrated values S1, S2... Sn, and integrated integrated values S1, S2. Using the Sn and predetermined coefficients k1, k2,.
D = k1 × S1 + k2 × S2 +... + Kn × Sn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,..., Kn ≧ 0)
Means for calculating based on the following formula: a comparing means for comparing the photoreceptor damage index calculated by the calculating means with a predetermined life information of the photoreceptor, based on the result of the comparing means When the photoconductor damage index calculated by the calculation unit is equal to or longer than the predetermined life information of the life of the photoconductor, a warning unit or a notification unit that warns or displays the life of the photoconductor includes: Be provided,
The process cartridge includes a storage unit that stores the integrated value.
[0042]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for detecting the life of an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge according to the present invention will be described in more detail with reference to the drawings.
[0043]
Example 1
First Embodiment A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a printer (LBP) that performs exposure using laser light, which is an image forming apparatus of the present embodiment.
[0044]
The printer of the present embodiment includes a process cartridge 17 in which process means of an electrophotographic photosensitive member 1, which is a photosensitive drum, a charging roller 2, a developing device 7, and a cleaning device 14, are incorporated, a transfer roller 13, a fixing device 15, an optical device. A laser scanner 4, a mirror 6, and the like are provided as a system. The process cartridge 17 is exchangeably mounted on the apparatus main body by the mounting guide means 80.
[0045]
The image forming process of this printer will be described below.
[0046]
The photoreceptor 1 has an outer diameter of 30 mm, is formed by laminating a photoconductive photosensitive layer 1a on the surface of a conductive base 1b made of aluminum, and rotates at a peripheral speed of 100 mm / sec in the direction of arrow A in the figure. Driven.
[0047]
The photoreceptor 1 receives a negative uniform charge by a charging roller 2 and then responds to a time-series electric digital image signal of image information output from a laser scanner 4 and sent from a video controller (not shown). With the laser exposure 5 described above, scanning exposure is performed at a resolution of 600 dpi, and an electrostatic latent image is formed on the surface via a mirror 6 installed in the image forming apparatus main body.
[0048]
The electrostatic latent image on the photoreceptor 1 is reversely developed by the toner 8 carried on the developing sleeve 11 in the developing device 7, and is visualized as a toner image.
[0049]
The toner image is transferred onto the transfer paper P by the transfer roller 13. Then, the transfer paper P to which the toner image has been transferred is separated from the photoreceptor 1 and introduced into the fixing device 15 through the conveying means 70, where the toner image is fixed, and then discharged from the image forming apparatus main body. Is done. After the transfer process, the photoreceptor 1 is cleaned of residual toner by the cleaning device 14 and is subjected to the charging process again.
[0050]
Incidentally, the developing device 7 employs a non-contact developing method, and includes a developing sleeve 11 and a developing sleeve 11 which are rotatably supported toner carriers which carry the toner 8 and transport it to the photoreceptor 1. And a toner storage chamber 3 fixed therein.
[0051]
The developing sleeve 11 is connected to a power supply 16 to which an AC bias and a DC bias can be applied. In this embodiment, when a DC component of −500 V is supplied to a rectangular wave having a peak-to-peak voltage of 1200 V, the developing sleeve 11 is thinned on the developing sleeve 11. The toner 8 applied to the layer is developed on the photoconductor 1 at a portion facing the photoconductor 1.
[0052]
In this embodiment, the toner 8 uses a magnetic one-component toner and is stored in the toner storage chamber 3.
[0053]
The charging roller 2 has a two-layer structure in which a sponge layer 2b and a surface layer 2c are wound around a cored bar 2a. The core 2a has a diameter of 6 mm, the outer diameter of the roller is 12 mm, and the roller length is about 220 mm. Both ends of the core bar 2a are pressurized by 500 gf each in the direction of the arrow c in the drawing, and are in contact with the photoconductor 1 with a nip of about 1.5 mm.
[0054]
The charging roller 2 is not driven, and is configured to rotate following the photoconductor 1.
[0055]
Further, the charging roller 2 is connected to a primary bias application power supply 12 via a metal core 2a. In this embodiment, during the rotation of the photoconductor, an AC bias (peak-to-peak) is applied to a part including the image forming area as the bias application condition 1. A bias in which a DC bias of -700 V is superimposed on a voltage of 1600 V, a frequency of 1000 Hz, and a sine wave is applied to uniformly charge the surface of the photoconductor 1 to about -680 V. Further, in other portions during the rotation of the photoconductor, there are a portion where only -1250 V is applied as the bias application condition 2 and the surface of the photoconductor 1 is charged to about -680 V, and a portion where no bias is applied as the bias application condition 3. (See FIG. 3).
[0056]
Here, in the present embodiment, bias application condition 1; AC bias is used to obtain a uniform good image in the image area and to eliminate the surface potential at the end of printing. Bias application condition 2; Is not required, but a constant surface potential is required for preventing unnecessary development of toner from the developing device, cleaning of the transfer member, etc., and using only a DC bias that causes little damage to the photosensitive drum, a bias application condition 3: Switching is performed for the purpose of not applying a bias since a constant surface potential is not required.
[0057]
For the same purpose as the bias application condition 2, there is a method of lowering the voltage value (or current value) of the AC bias, lowering the frequency, and the like, and is similarly effective.
[0058]
Next, a method for detecting the life of the electrophotographic photosensitive member, which is a feature of the present invention, will be described. FIG. 3 shows a printing operation sequence, and FIG. 4 shows a flowchart relating to a method for detecting the life of the photoconductor.
[0059]
In FIG. 1, the rotation of the photoconductor 1 is controlled by a photoconductor rotation instructing unit 22, and an AC bias and a DC bias are applied to a charging roller 2 serving as a contact charging member from a primary bias application power supply 12 as appropriate. The voltage output instruction unit 21 and the primary DC voltage output instruction unit 20 independently control and apply the voltage. The primary AC voltage output instruction unit 21, the primary DC voltage output instruction unit 20, and the photoconductor rotation instruction unit 22 are connected to a bias application time detection unit 23, and the application time t1 of each bias application condition in one print operation job. , T2, t3 are detected.
[0060]
Here, as shown in the print operation sequence of FIG. 3, t1 is the application time information Tac (t1 = Tac = Tac1 + Tac2) from the primary AC voltage output instruction unit 21, and t2 is the application time from the primary DC voltage output instruction unit 20. The information Tdc is obtained by subtracting the time Tacdc during which the primary AC voltage is superimposed (t2 = Tdc−Tacdc), and t3 is obtained by subtracting t1 and t2 from the photoconductor rotation time information Tdr from the photoconductor rotation instruction unit 22 ( t1 = Tdr− (t1 + t2)).
[0061]
As described above, the application time t1, 2t, and t3 under each bias application condition is detected by the bias application time detection unit 23 (Step 1 (S1)).
[0062]
After one job of the printing operation is completed, the application time t1, t2, and t3 of each bias application condition is transferred to the photoconductor damage calculation unit 24, and the photoconductor damage index D is calculated by the following equation (1) (S2). ).
[0063]
D = k1 × t1 + k2 × t 2 + K3 × t3 (1)
In the above equations, each coefficient is k1 = 1, k2 = 0.3, and k3 = 0.1.
[0064]
The photoconductor damage accumulation storage unit 25 updates the photoconductor damage accumulation value S by adding the photoconductor damage index D for one job to the stored photoconductor damage accumulation value S (Snew = Sold + D, S3). This operation is repeated for each print job. When one job is completed and the update of the integrated value S stored in the photoconductor damage integration storage unit 25 is completed, the comparison unit 26 reads the preset life information R from the photoconductor life information storage unit 27, and The magnitude relationship with the updated photosensitive member damage integrated value S is compared (S4, S6).
[0065]
As a result, if the updated integrated value S is larger than the life information R, a signal is sent to the warning unit (display unit) 28 to warn or display that the life is reached (S5).
[0066]
If the photoconductor damage integrated value S is smaller than the warning (lifetime) information in step 4 (S4), the process returns to the normal operation without displaying any warning or the like (S7).
[0067]
As shown in the sequence of FIG. 3, the photoconductor rotation time, the primary DC application time, the primary AC application time, or the transfer bias application time are different from each other.
[0068]
As a result of the present inventors' studies focusing on damage to the photoconductor 1 in each state in the sequence, particularly on drum abrasion, if the drum abrasion in a state where no bias is applied is set to 1, the primary DC It has been found that there is a large difference between abrasion of the drum when the bias is applied and abrasion of the drum when the primary AC bias is applied, and between 8 and 10. These results were obtained by examining a system using an OPC photoconductor having a surface layer containing a polycarbonate resin as a main binder, and using blade cleaning as a photoconductor cleaning.
[0069]
From the above examination results, when it is considered that the life of the photoconductor 1 is determined to be dominantly determined by the drum scraping, the application time for each bias application condition is multiplied by a coefficient, and the total calculated value is integrated to integrate the drum scraping. By estimating the amount and judging the life, accurate life detection can be performed.
[0070]
The conventionally proposed method uses corona charging, in which the drum rotation time and the drum scraping amount are almost proportional.Accordingly, by integrating the drum rotation number or the drum rotation time, it is possible to detect the life accurately. However, as described above, in a system in which contact charging is used as the charging means and an AC bias is applied, the drum rotation time is not proportional to the drum scraping amount, and accurate life detection cannot be performed.
[0071]
Further, by integrating the time during which the transfer bias is applied, it is possible to estimate the time during which AC is applied to some extent. However, as shown in the sequence of FIG. 3, the AC bias is longer than the image area. Since the voltage is applied and the voltage is also applied at the end of the printing operation, there is a difference from the application time Ttr of the transfer bias applied almost only to the image area, and this difference lowers the accuracy of the life detection. Will be.
[0072]
In this embodiment, the application time t1, t2, and t3 of each bias application condition in one job of the printing operation is detected by the bias application time detection unit 23, and the photoconductor damage index D is calculated by the photoconductor damage calculation unit 24 in advance. By calculating using the formula (1) above and each coefficient, and updating the photoconductor damage integrated value S with the latest integrated value, it is possible to estimate the amount of drum scraping of the photoconductor 1 and accurately detect the life. It becomes.
[0073]
In the present embodiment, the sponge charging roller is used as the contact charging member, but may be a solid rubber roller, and is not limited to the roller shape, but may be a blade shape, a brush shape, a brush roller, or the like. It doesn't matter.
[0074]
In the present embodiment, the calculation coefficient of the photoconductor damage is:
k1 = 1, k2 = 0.3, k3 = 0.1
However, since it changes depending on the photoreceptor material, the combination of the bias application conditions, the cleaning method, and the like, the optimum value may be appropriately selected in each system. In the sequence, a term of the bias application condition which does not significantly affect the scraping of the photosensitive drum (the operation coefficient kn is significantly smaller than k1 and the application time tn is significantly smaller than t1) is required. It may be omitted to the extent that accuracy is not reduced.
[0075]
In this embodiment, an example is described in which a process cartridge is used in which a photosensitive member, a charging roller, a developing device, and a cleaning device are integrated, but the same applies to an image forming apparatus in which a single photosensitive member is replaced as a consumable item. Needless to say, there is an effect.
[0076]
Example 2
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 5 and FIG. 1 described above.
[0077]
In the present embodiment, information for determining the life of the photoconductor is set in two stages in the photoconductor life information storage unit 27 of FIG. That is, since the life of the photosensitive member is approaching, the warning information Y for instructing the user to prepare for replacement is set, and the life information R which is the true photosensitive member life is set in two stages. . Naturally, the relationship is such that the warning information Y <the photoconductor life R.
[0078]
In FIG. 1, the rotation of the photoconductor 1 is controlled by a photoconductor rotation instructing unit 25. The charging roller 2 serving as a contact charging member is supplied with an AC bias and a DC bias from a primary bias application power supply 12 as appropriate. It is controlled and applied independently by the output instruction unit 21 and the primary DC output instruction unit 20.
[0079]
The primary AC voltage output instruction unit 21, the primary DC voltage output instruction unit 20, and the photoreceptor rotation instruction unit 22 are connected to a bias application time detection unit 23, and the application time of each bias application condition in one job of the printing operation. t1, t2, and t3 are detected (S11).
[0080]
After one job of the printing operation is completed, the application time t1, t2, and t3 of each bias application condition is transferred to the photoconductor damage calculation unit 24, and the photoconductor damage index D is calculated by the following equation (1) shown in the first embodiment. ▼,
D = k1 × t1 + k2 × t2 + k3 × t3 (1)
(In the above equation, the coefficients are k1 =, k2 = 0.3, and k3 = 0.1.)
Is calculated by
[0081]
The photoconductor damage accumulation storage unit 25 updates the photoconductor damage accumulation value S by adding the photoconductor damage index D for one job to the stored photoconductor damage accumulation value S (Snew = Sold + D, S13).
[0082]
This operation is repeated for each job of the printing operation. When one job is completed and the update of the integrated value S stored in the photoconductor damage integration storage unit 25 is completed, the comparison unit 26 reads the preset warning information Y and the life information R from the photoconductor life storage unit 27. Is read (S16), and the updated integrated value S is read from the photoconductor damage integrated storage unit 25.
[0083]
First, the integrated value S is compared with the warning information Y (S14). If the updated integrated value S is smaller than the warning information Y, the process returns to the normal print sequence and the life information of the photoconductor 1 is displayed. No (S17).
[0084]
If the result of comparing the integrated value S with the warning information Y is S ≧ Y, the integrated value S is compared with the life information R (S15). If S <R, the warning unit (display unit) is instructed to prompt the user to prepare for replacement while continuing the normal operation because the life of the photoconductor is approaching (S18).
[0085]
If S.gtoreq.R, the user is notified of the life of the photoconductor to the photoconductor life warning unit (display unit) 28, and is instructed to prompt the user to replace the photoconductor. S19). When it is confirmed that the photoconductor 1 has been newly replaced, the printing operation is permitted again.
[0086]
In this embodiment, the information for determining the life of the photoconductor is set in two stages of the warning information and the life information. However, the information is set more finely and the detailed life information of the photoconductor is presented to the user. Needless to say, this may be done.
[0087]
By the above, the user can sense that the life of the photoconductor is near and the time to replace it is near, so that a new photoconductor can be prepared in advance and replaced immediately when the life of the photoconductor expires. In such a case, since the apparatus is stopped, it is possible to prevent the main body from being damaged by performing printing after the end of its life.
[0088]
Example 3
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS. Since the schematic configuration of the image forming apparatus is the same as that of the first embodiment, only the different points will be described.
[0089]
In the first embodiment, the process cartridge is configured by integrating the electrophotographic photosensitive member 1, the charging roller 2, the developing device 3, and the cleaning device 14, but in the present embodiment, the electrophotographic photosensitive member 1, A drum unit (process cartridge) 29 in which the charging roller 2 and the cleaning device are integrated is integrated, and can be exchanged with respect to the apparatus main body by the mounting guide means 80. The developing device 7 is a separate unit. A storage element 30 serving as a storage unit is mounted in the drum unit 29, and a connection terminal (not shown) is provided in a container of the drum unit 29 so as to communicate with a control unit of the main body when the drum unit 29 is mounted on the image forming apparatus. ) Is provided.
[0090]
The image forming process is the same as that in the first embodiment, and a description thereof will not be repeated.
[0091]
In FIG. 6, the rotation of the photoconductor 1 is controlled by a photoconductor rotation instructing unit 22, and the charging roller 2, which is a contact charging member, receives an AC bias and a DC bias from a primary bias application power supply 12 as appropriate. The voltage output instruction unit 21 and the primary DC voltage output instruction unit 20 independently control and apply the voltage.
[0092]
The primary AC voltage output instruction unit 21, the primary DC voltage output instruction unit 20, and the photoconductor rotation instruction unit 22 are connected to a bias application time detection unit 23, and the application time t1 of each bias application condition in one print operation job. , T2, t3 are detected (S21).
[0093]
After one job of the printing operation is completed, the application time t1, t2, and t3 of each bias application condition is passed to the photoconductor damage calculation unit 24, and the photoconductor damage index D is calculated by the following equation (1).
D = k1 × t1 + k2 × t2 + k3 × t3 (1)
(Here, the above coefficients are k1 =, k2 = 0.3, and k3 = 0.1.)
Is calculated by
[0094]
The photoconductor damage calculation unit 24 is connected to the storage element 30 in the drum unit 29, and reads the photoconductor damage integrated value S from the storage element 30 for each job to update the photoconductor damage integrated value S (S22). ).
[0095]
In this operation, when one job of the printing operation is completed and the update of the integrated value S stored in the storage element 30 of the drum unit 29 is completed (S23), the comparing unit 26 updates the integrated value S from the storage element 30 of the drum unit 29. The integrated value S and the life information R set and stored in advance are read, and the magnitude relation between the two is compared (S24). As a result, when the updated integrated value S is larger than the life information R (S ≧ R), a signal is sent to a warning unit (display unit) 28 to warn or display that the life is over, and the printing operation of the main body is performed. It is prohibited (S25).
[0096]
If the integrated value S is smaller than the life information R (S <R), the process returns to the normal operation without displaying a warning (S26).
[0097]
In the present embodiment, since the storage element 30 is provided in the drum unit 29, the photoconductor damage index stored for each unit is different, so that the unit can be easily identified. In other words, when a new unit is replaced, even if the user mistakenly installs an old unit, it can be determined without providing special identification means, so that a user's replacement mistake can be prevented, and a drum unit that has exceeded the life span can be mistakenly replaced. Use of the device can prevent problems such as outputting a defective image.
[0098]
In addition, by storing information R on the life of the photosensitive drum in the storage element 30 of the drum unit 29 in advance, even when drum units having different lifespans are mounted, the lifespan is appropriately detected according to the respective lifespans and a warning is issued. be able to.
[0099]
Example 4
Next, a fourth embodiment of the present invention will be described with reference to FIGS. Since the schematic configuration of the image forming apparatus is the same as that of the first embodiment, only the differences will be described.
[0100]
In the present embodiment, similarly to the third embodiment, the electrophotographic photosensitive member 1, the charging roller 2, and the cleaning device 14 are integrated into a drum unit (process cartridge) 29, and the developing device 7 is a separate unit. Is an example in which the storage element 30 is mounted. Similarly, the container of the drum unit 29 is provided with a connection terminal (not shown) so that it can communicate with a control unit of the main body of the image forming apparatus when the main body is mounted on the main body of the image forming apparatus.
[0101]
The feature of the present embodiment is that the life detecting method of the photoconductor of the first to third embodiments detects the application time t1, t2, t3 of each bias application condition in one job of the printing operation, and the photoconductor damage calculating unit. After calculating the photoreceptor damage index, the photoreceptor damage integrated value is stored in the photoreceptor damage integrated storage unit of the main body or the storage element of the drum unit, but the application time t1, t2, t3 of each bias application condition It is integrated and stored in each integrated value S1, S2, S3, and the integrated values S1, S2, S3 are read out at an arbitrary timing, and the total photosensitive member damage index is calculated using the coefficients k1, k2, and k3 in the photosensitive member damage calculation unit. D is expressed by equation (2),
D = k1 × S1 + k2 × S2 + k3 × S3 (2)
Further, the values of the coefficients k1, k2, and k3 are made variable by the ratio of the integrated values S1, S2, and S3 of the application time under each bias application condition.
[0102]
A method of detecting the life of the photoconductor, which is a feature of the present invention, will be described with reference to the flowcharts of FIGS.
[0103]
In FIG. 8, the rotation of the photoconductor 1 is controlled by a photoconductor rotation instructing unit 22, and an AC bias and a DC bias are appropriately applied to a charging roller 2 as a contact charging member from a primary bias application power supply 12. The output instruction unit 21 and the primary DC voltage output instruction unit 20 independently control and apply the voltage.
[0104]
The primary AC voltage output instructing unit 21, the primary DC output instructing unit 20, and the photoreceptor rotation instructing unit 22 are connected to a bias application time detecting unit 23, and the application time t1 of each bias application condition in one job of the printing operation, t2 and t3 are detected (S31).
[0105]
After one job of the printing operation is completed, the application conditions t1, t2, and t3 of the respective bias application conditions are transferred to the photoconductor damage calculation unit 24, and the photoconductor damage calculation unit 24 is connected to the storage element 30 in the connected drum unit 29. From the stored application times S1, S2, and S3 of the application time of each bias application condition of the photoconductor, and the application time t1, t2, and t3 of each bias application condition for one job are added to the read value. The integrated values S1, S2, S3 of the application time of each bias application condition stored in the storage element 30 are updated (S32, S33).
[0106]
Then, using the updated integrated values S1, S2, and S3 of the application time of each bias application condition, the photoconductor damage index D is calculated by the equation (2),
D = k1 × S1 + k2 × S2 + k3 × S3 (2)
Is calculated (S34).
[0107]
At this time, the values of the coefficients k1, k2, and k3 are appropriately adjusted by the ratio of the integrated values S1, S2, and S3 of the application time under each bias application condition. In this embodiment, the integrated value S1 of the application time of the bias application condition 1 (the bias in which the DC bias −700 V is superimposed on the AC bias having the sine wave, the frequency of 1000 Hz, and the peak-to-peak voltage of 1600 V) having the largest influence on the photoreceptor drum scraping is used. , The ratio ρ of the application time integrated value S1 of the bias application time condition 1 to the photosensitive drum rotation time (S1 + S2 + S3) is calculated, and
k1 = 1, k2 = 0.5 × ρ, k3 = 0.2 × ρ
And
[0108]
When the calculation of the photoconductor damage index is completed, the comparing unit 26 reads the life information R which is set in advance and stored from the storage element 30 of the drum unit 29 and compares the calculated photoconductor damage index D with the magnitude relationship. (S35).
[0109]
As a result, if the calculated photoconductor damage index D is larger than the life information R (D ≧ R), a signal is sent to a warning unit (display unit) 28 to warn or display that the life is reached (S36).
[0110]
If the photoreceptor damage index D is smaller than the life information R, the process returns to the normal operation without displaying any warning or the like (S37).
[0111]
As in the present embodiment, the coefficients k2 and k3 relating to the integrated application time values S2 and S3 of the bias application conditions 2 and 3 are changed by the ratio of the integrated application time value S1 of the bias application condition 1 to the photosensitive drum rotation time (S1 + S2 + S3). The reason is based on the following experimental results.
[0112]
That is, as described in the first embodiment, there is a difference in the damage (mainly, the scraping amount) of the photosensitive drum due to a difference in the bias application conditions such as the application of the AC bias, the application of only the DC bias, and the absence of the bias. In particular, it was confirmed by experiments that the amount of scraping of the photosensitive drum when the AC bias was applied was larger than in other cases.
[0113]
Further, the present inventors believe that the degree of the AC bias application time during the rotation time of the photosensitive drum also affects the shaving amount of the photosensitive drum under other bias application conditions. An experiment was conducted in which the rate of application of the AC bias was changed from 50% to 70%, and the amount of scraping of the photosensitive drum per unit time was measured.
[0114]
As a result, as the AC bias application time ratio becomes larger, the amount of scraping of the photosensitive drum under other bias application conditions is set to 1, and 0.20 → 0.4 when only DC bias is applied, and 0 when no bias is applied. It was found that the number increased from 0.1 to about 0.15. This experiment was also performed in the same manner as in Example 1, using an OPC photoconductor having a surface layer using a polycarbonate resin as a main binder as the photoconductor 1, and using a blade cleaning as a photoconductor cleaning.
[0115]
Based on the above results, in the present embodiment, the calculation coefficients k1, k2, and k3 of the damage index of the photosensitive drum are simply determined by the ratio ρ of the integrated application time S1 of the bias application condition 1 to the photosensitive drum rotation time (S1 + S2 + S3).
k1 = 1, k2 = 0.5 × ρ, k3 = 0.2 × ρ
Was set.
[0116]
In the case where the life of the photosensitive drum is short (for example, about 10,000 sheets can be passed), even if the calculation coefficients k1, k2, and k3 of the damage index of the photosensitive drum are constants as in the first to third embodiments, the conventional method is sufficient. Although the accuracy can be improved, if the life of the photosensitive drum is long (for example, about 50,000 sheets can be passed), the error increases in proportion to the increase in the number of endurable sheets, so the calculation coefficient is changed as in this embodiment. It is possible to improve the accuracy more by doing.
[0117]
As in the present embodiment, the storage element 30 is provided in the drum unit 29, and the application times t1, t2, and t3 under each bias application condition are integrated into the integrated values S1, S2, and S3, and stored in the storage element 30, and At the timing (1), the integrated values S1, S2, and S3 are read, and the photosensitive member damage calculating unit 24 obtains the total photosensitive member damage index D using the coefficients k1, k2, and k3 determined by the ratio of the integrated values S1, S2, and S3. Is used, the life of the photoconductor can be accurately estimated.
[0118]
In addition, by collecting the used drum unit 29, it is possible to collect a lot of information on the actual market usage, and to fine-tune the operation coefficient based on the data to achieve higher accuracy. be able to.
[0119]
However, for the purpose of accurately estimating the life of the photoconductor, the integrated values S1, S2, and S3 of the application times t1, t2, and t3 of each bias application condition may be stored in the image forming apparatus main body. As in the first to third embodiments, the application time t1, t2, and t3 of each bias application condition in one job is detected, and the photoconductor damage index is calculated by the photoconductor damage calculation unit, and then the photoconductor damage integrated storage of the main body is stored. When the photosensitive member damage index is calculated for each job in the method of storing the photosensitive member damage integrated value in the storage element of the unit or the drum unit, the ratio of the application time t1, t2, t3 of each bias application condition in one job Even if the coefficients k1, k2, and k3 are changed to obtain the photoconductor damage index in one job, the same effect can be obtained.
[0120]
Further, in the present embodiment, the coefficients are calculated as k1 = 1, k2 = 0.5 × ρ, and k3 = 0.2 × ρ by a simple expression of the calculation coefficient of the photoconductor damage.
However, since it changes depending on the photoconductor material, the combination of bias application conditions, the cleaning method, etc., the optimum value and the variable method may be appropriately selected in each system.
[0121]
Further, when the resistance value of the charging member due to environmental fluctuations, durability fluctuations, etc., and the capacitance fluctuation of the photosensitive drum due to scraping of the photosensitive drum, the voltage value and current value of the AC bias are changed, and the amount of damage to the photosensitive drum is also changed. It is also effective to provide a means for detecting the voltage value or the current value of the AC bias, thereby changing the operation coefficient when the AC bias is applied.
[0122]
Example 5
In the first to fourth embodiments, the case where the present invention is applied to the monocolor laser beam printer shown in FIGS. 1, 6, and 8 has been described. In the fifth embodiment, the present invention is described with reference to FIGS. 11 is applied to a full-color laser beam printer of yellow, magenta, cyan, and black.
[0123]
In FIG. 10, the photosensitive drum 71 is driven in a direction indicated by an arrow by a driving unit (not shown), and is uniformly charged to a predetermined potential by a roller charger 72. Next, a laser beam is applied to the photosensitive drum 71 by the exposure device 73 to which a signal according to the yellow image pattern is input, and a latent image is formed on the photosensitive drum 71.
[0124]
When the photosensitive drum 71 further moves in the direction of the arrow, of the developing devices 74a, 74b, 74c, and 74d supported by the support 75, for example, the developing device 74a containing yellow toner is opposed to the photosensitive drum 71. 5 is rotated, and the latent image is visualized by the developing device 74a. Next, the developed toner image is transferred onto an intermediate transfer belt 66 which is an intermediate transfer body.
[0125]
The intermediate transfer belt 66 is stretched on three support rollers 61, 62, 63, and moves in the direction of the arrow in the figure by rotating the support roller 62 connected to a drive source (not shown). Further, a primary transfer roller 64 is provided at the photosensitive drum facing portion inside the intermediate transfer belt 66, and a predetermined bias is applied from a high voltage power supply (not shown), and the toner on the photosensitive drum 71 is transferred onto the intermediate transfer belt 66. Transcribed.
[0126]
The above steps are further performed, for example, in the order of magenta, cyan, and black by the developing devices 74b, 74c, and 74d, so that four-color toner images are formed on the intermediate transfer belt 66.
[0127]
The four color toner images are collectively transferred by the secondary transfer roller 65 onto transfer paper conveyed from the paper feeding device 76 via the conveying means 77 in synchronization with the movement of the intermediate transfer belt 66. Further, the transfer paper is melted and fixed by the heating / pressure fixing device 78 to obtain a color image.
[0128]
The transfer residual toner on the photosensitive drum 71 is cleaned by a cleaning device 79 having blade means.
[0129]
In this embodiment, the charging roller 72, the photosensitive drum 71, and the cleaning device 79 are configured as an integrated process cartridge 90 so as to have an appearance as shown in FIG. 80 makes it detachable. Further, a storage unit 84 that functions similarly to the cartridge memory unit 4 of the above-described embodiment is provided.
[0130]
Each of the four color developing units 74a to 74d is configured to be detachable from the apparatus main body, similarly to the process cartridge. With these configurations, the user can easily perform the replacement and maintenance of the above-described members, which has been conventionally performed by a service person.
[0131]
By applying the present invention described in Embodiments 1, 2, 3, and 4 to the full-color image forming apparatus having the above-described configuration, the same operation and effect as described above can be obtained.
[0132]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to accurately detect the life of the electrophotographic photosensitive member, and to stop the operation of the apparatus main body, thereby preventing the main body damage due to printing after the life, Further, a method for detecting the life of an electrophotographic photosensitive member, which can accurately detect that the replacement time due to the life of the electrophotographic photosensitive member is near, an image forming apparatus and a process cartridge using the life detecting method, and an image forming apparatus including the process cartridge A device can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment.
FIG. 2 is a configuration diagram illustrating a process cartridge mounted on the image forming apparatus of FIG. 1;
FIG. 3 is a diagram illustrating a timing chart of image formation according to the first exemplary embodiment.
FIG. 4 is a flowchart of life detection according to the first embodiment.
FIG. 5 is a flowchart for detecting the life of the image forming apparatus according to the second embodiment.
FIG. 6 is a schematic configuration diagram illustrating an image forming apparatus according to a third embodiment.
FIG. 7 is a flowchart for detecting the life of the image forming apparatus according to the third embodiment.
FIG. 8 is a schematic configuration diagram illustrating an image forming apparatus according to a fourth embodiment.
FIG. 9 is a flowchart for detecting the life of the image forming apparatus according to the fourth embodiment.
FIG. 10 is a schematic configuration diagram illustrating an image forming apparatus according to a fifth embodiment.
FIG. 11 is an external view of a process cartridge mounted on an image forming apparatus according to a fifth embodiment.
[Explanation of symbols]
1 Photosensitive drum (electrophotographic photoreceptor)
2 Charging roller (charging means)
7, 75 developing device (developing means)
10 Developing sleeve
14 Cleaning means
17, 29, 90 Process cartridge
23 Bias application time detection unit (detection means)
24 Photoconductor damage calculation unit (calculation means)
25 Photoconductor damage accumulation storage unit (accumulation means)
26 Comparison section (comparison means)
28 Warning part (display part, warning means, notification means)
30, 84 storage element (storage means)
70, 77 conveying means
80 Mounting means

Claims

In a method for detecting the life of a photoconductor of an image forming apparatus that forms an image on a recording medium,
The voltage applied to the charging unit for charging the photoconductor includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged. wherein, and during the rotation of the photosensitive member, as a bias applying condition to the charging means, when there is no time and DC bias component is a DC bias component, and a first bias application condition for applying an AC bias, without bias , it applied only DC bias, the AC bias, at least one second n type comprising a bias application conditions, the one of the application, three by varying the voltage or current value or frequency of the (n ≧ 2) With bias application conditions,
The image forming apparatus main body uses the respective times t1, t2... Tn under the bias application condition n and predetermined coefficients k1, k2. k1 × t1 + k2 × t2 +... + kn × tn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
The damage index D of the photoreceptor is integrated with the integrated value of the photoreceptor damage, and the integrated value is compared with a predetermined lifetime information of the photoreceptor, and When the integrated photoconductor damage integrated value is equal to or longer than a predetermined integrated time as the photoconductor life based on the comparison result, the life of the photoconductor is warned or displayed. Body life detection method.

2. The method according to claim 1, wherein, when calculating the damage index, the values of the coefficients k1, k2,... Kn are changed according to the ratio of the times t1, t2,.

In a method for detecting the life of a photoconductor of an image forming apparatus that forms an image on a recording medium,
The voltage applied to the charging unit for charging the photoconductor includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged. wherein, and during the rotation of the photosensitive member, as a bias applying condition to the charging means, when there is no time and DC bias component is a DC bias component, and a first bias application condition for applying an AC bias, without bias , applied only DC bias, said AC bias voltage or current value or applied by changing the frequency less when one of the second bias application conditions and, n type comprising of three (n ≧ 2) With bias application conditions of
The image forming apparatus main body integrates the respective times t1, t2... Tn under the bias application condition n into integrated values S1, S2... Sn, and obtains the integrated values S1, S2. Using predetermined coefficients k1, k2,... Kn, the damage index D of the photoconductor is calculated as D = k1 × S1 + k2 × S2 +.
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
The damage index D is compared with a predetermined life information R which is a predetermined life of the photoconductor, and the damage index D is determined based on the comparison result. A warning or display of the life of the photoconductor when the life of the photoconductor is equal to or longer than the integrated time.

4. The method according to claim 3, wherein when calculating the damage index, the values of the coefficients k1, k2,... Kn are changed according to the ratio of the integrated values S1, S2,.

5. The method according to claim 1, wherein the charging unit is provided in contact with the photoconductor.

In an image forming apparatus for forming an image on a recording medium,
A charging unit for charging the photoconductor, wherein the voltage applied to the charging unit includes a DC bias component and an AC bias component when the photoconductor is charged, and a DC bias component when the photoconductor is discharged. comprises an AC bias component without, and during the rotation of the photosensitive member, as a bias applying condition to the charging means, when there is no time and DC bias component is a DC bias component, the first bias application that applies an AC bias n with the condition, without bias application, applying DC bias only, of the AC bias, the least when one of the second bias application conditions of the application, three by varying the voltage or current value or frequency, the The image forming apparatus main body has different types of (n ≧ 2) bias application conditions. ... using a predetermined coefficient k1, k2 ... kn and tn, the damage index D of the photosensitive member D = k1 × t1 + k2 × t2 + ··· + kn × tn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
Means for calculating the damage index D of the photoreceptor to an integrated value of the photoreceptor damage, and a life of the photoreceptor which is predetermined by the integrated value integrated by the integration means. Means for comparing the life information to be performed, and when the photosensitive member damage integrated value integrated by the integrating means based on the result of the comparing means is equal to or longer than the life information to be a predetermined life of the photosensitive member, An image forming apparatus comprising: a warning unit or a notification unit that warns or displays the life of the photoconductor, and a conveyance unit that conveys the recording medium.

In order to prompt preparation for replacement of the photoconductor before the photoconductor reaches the end of its life, warning information smaller than at least one or more of the life information previously determined, and the life information and the photoconductor damage integrated value and Comparing means for comparing, and when the integrated value integrated by the integrating means is equal to or greater than predetermined warning information based on the result of the comparing means, warns or displays the preparation for replacing the photoconductor, and Means for warning or displaying the life of the photoconductor when the integrated value integrated by the integrating means based on the result of the means is equal to or longer than predetermined life information, and the warning means or display means 7. The image forming apparatus according to claim 6, wherein the image forming operation of the image forming apparatus main body is stopped when the life of the photoconductor is warned or displayed.

8. The image forming apparatus according to claim 6, wherein at the time of calculating the damage index, the values of the coefficients k1, k2... Kn are changed according to the ratio of the times t1, t2.

In an image forming apparatus for forming an image on a recording medium,
A charging unit for charging the photoconductor, wherein the voltage applied to the charging unit includes a DC bias component and an AC bias component when the photoconductor is charged, and a DC bias component when the photoconductor is discharged. comprises an AC bias component without components, and during the rotation of the photosensitive member, as a bias applying condition to the charging means, when there is no time and DC bias component is a DC bias component, a first bias applied an AC bias An application condition and at least one second bias application condition out of three of: no bias application, only DC bias application, and application of the AC bias by changing a voltage value or a current value or a frequency are provided. It has n kinds (n ≧ 2) of bias application conditions,
The image forming apparatus main body includes integrating means for integrating the respective times t1, t2... Tn under the bias application condition n into integrated values S1, S2... Sn, and integrated integrated values S1, S2. Using the Sn and predetermined coefficients k1, k2,... Kn, the damage index D of the photoreceptor is calculated as D = k1 × S1 + k2 × S2 +.
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
Means for calculating based on the following formula; comparing means for comparing the photoreceptor damage index D calculated by the calculating means with predetermined life information as the life of the photoreceptor; When the photoconductor damage index calculated by the calculation unit based on the life information is a predetermined life of the photoconductor or longer, a warning unit or a notification unit that warns or displays the life of the photoconductor, Conveying means for conveying the recording medium,
An image forming apparatus comprising:

In order to prompt the preparation for replacing the photoconductor before the photoconductor reaches the end of its life, warning information smaller than at least one or more of the life information previously determined, and the life information and the photoconductor damage index and Comparing means for comparing, and based on the result of the comparing means, when the photoreceptor damage index calculated by the calculating means is equal to or more than predetermined warning information, a warning or display is displayed for preparation for replacing the photoreceptor. Means for warning or displaying the life of the photoreceptor when the photoreceptor damage index calculated based on the result of the comparing means is equal to or longer than predetermined life information, the warning means or the display means 10. The image forming apparatus according to claim 9, wherein when the life of the photoconductor is warned or displayed, the image forming operation of the image forming apparatus main body is stopped.

11. The method according to claim 9, wherein, when calculating the damage index, the values of the coefficients k1, k2,... Kn are changed according to the ratio of the calculated integrated values S1, S2,. Image forming device.

A process cartridge detachable from an image forming apparatus main body, comprising: a photosensitive member; and a charging unit configured to charge the photosensitive member.
The voltage applied to the charging means includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged, and applied during rotation of the body, as a bias applying condition to the charging means, when there is no time and DC bias component is a DC bias component, and a first bias application condition for applying an AC bias, no bias application, DC bias only , And applying at least one of the second bias application conditions of the AC bias while changing the voltage value, the current value, or the frequency, of n types (n ≧ 2) of the bias application conditions. Holding
The image forming apparatus main body uses the respective times t1, t2... Tn under the bias application condition n and predetermined coefficients k1, k2. k1 × t1 + k2 × t2 +... + kn × tn
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,... Kn ≧ 0)
Means for calculating the damage index D of the photoreceptor to an integrated value of the photoreceptor damage, and a life of the photoreceptor which is predetermined by the integrated value integrated by the integration means. Means for comparing the life information to be performed, and when the photosensitive member damage integrated value integrated by the integrating means based on the result of the comparing means is equal to or longer than the life information to be a predetermined life of the photosensitive member, A warning means or a notification means for warning or displaying the life of the photoconductor, and
The process cartridge according to claim 1, further comprising a storage unit configured to store the integrated value.

The image forming apparatus main body includes warning information smaller than at least one or more of the predetermined life information, and the life information, in order to prompt preparation for replacement of the photoconductor before the life of the photoconductor reaches its life. Comparing means for comparing with the photosensitive member damage integrated value, and replacing the electrophotographic photosensitive member when the integrated value integrated by the integrating means is equal to or longer than predetermined life information based on the result of the comparing means. Warning means or display for warning or displaying the preparation, and warning or displaying the life of the photoconductor when the integrated value integrated by the integrating means based on the result of the comparing means is equal to or more than predetermined warning information. Means for stopping the image forming operation of the image forming apparatus main body when the life of the photosensitive member is warned or displayed by a warning means or a display means. 12 process cartridge.

14. The process cartridge according to claim 12, wherein said image forming apparatus main body has a unit for reading out the contents written in said storage unit.

15. The process cartridge according to claim 12, wherein the storage unit stores information on a life of the photoconductor.

16. The value of the coefficients k1, k2... Kn is changed according to the ratio of the times t1, t2... Tn when the damage index is calculated by the calculating means. Process cartridge.

17. The process cartridge according to claim 12, wherein the charging unit is provided in contact with the photoconductor.

A process cartridge detachable from an image forming apparatus main body, comprising: a photosensitive member; and a charging unit configured to charge the photosensitive member.
The voltage applied to the charging means includes a DC bias component and an AC bias component when the photoconductor is charged, and includes an AC bias component without the DC bias component when the photoconductor is discharged, and applied during rotation of the body, as a bias applying condition to the charging means, when there is no time and DC bias component is a DC bias component, and a first bias application condition for applying an AC bias, no bias application, DC bias only , And applying at least one of the second bias application conditions of the AC bias while changing the voltage value, the current value, or the frequency, of n types (n ≧ 2) of the bias application conditions. Holding
The image forming apparatus main body includes integrating means for integrating the respective times t1, t2... Tn under the bias application condition n into integrated values S1, S2... Sn, and integrated integrated values S1, S2. Using the Sn and predetermined coefficients k1, k2,... Kn, the damage index D of the photoreceptor is calculated as D = k1 × S1 + k2 × S2 +.
(However, t1 is the AC bias application time, k1> 0, k2> 0, k3 ≧ 0,..., Kn ≧ 0)
Means for calculating based on the following formula: a comparing means for comparing the photoreceptor damage index calculated by the calculating means with a predetermined life information of the photoreceptor, based on the result of the comparing means When the photoconductor damage index calculated by the calculation unit is equal to or longer than the predetermined life information of the life of the photoconductor, a warning unit or a notification unit that warns or displays the life of the photoconductor includes: Be provided,
The process cartridge according to claim 1, further comprising a storage unit configured to store the integrated value.

The image forming apparatus main body includes warning information smaller than at least one or more of the predetermined life information, and the life information, in order to prompt preparation for replacement of the photoconductor before the life of the photoconductor reaches its life. Comparing means for comparing the photoreceptor damage index with the photoreceptor damage index; and preparing the photoreceptor for replacement when the photoreceptor damage index calculated by the calculation means based on the result of the comparison means is equal to or greater than predetermined warning information. Means for warning or displaying the life of the photoconductor when the photoreceptor damage index calculated by the calculation means based on the result of the comparing means is equal to or longer than predetermined life information. Wherein when the warning means or the display means warns or displays the life of the photoconductor, the image forming operation of the image forming apparatus main body is stopped. The process cartridge of claim 18.

20. The process cartridge according to claim 18, wherein said image forming apparatus main body has means for reading out the contents written in said storage means.

21. The process cartridge according to claim 17, wherein the storage unit stores life information of the photoconductor.

22. When calculating the damage index by the calculating means, the values of the coefficients k1, k2... Kn are changed according to the ratio of the integrated values S1, S2. Or process cartridge.

23. The process cartridge according to claim 17, wherein the charging unit is provided in contact with the photoconductor.

24. The process cartridge according to claim 12, wherein the process cartridge includes a developing unit or a cleaning unit.