JP2004069834A

JP2004069834A - Color image forming apparatus

Info

Publication number: JP2004069834A
Application number: JP2002226166A
Authority: JP
Inventors: Takuo Nada; 名田　卓生; Ichiro Yasumaru; 安丸　一郎
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2002-08-02
Filing date: 2002-08-02
Publication date: 2004-03-04

Abstract

<P>PROBLEM TO BE SOLVED: To prevent both color slurring detection operation and correction operation after continuous printing, or one of them according to a condition. <P>SOLUTION: In this color image forming apparatus equipped with an optical unit for correcting color slurring by operating a part thereof, and a means for detecting the color slurring, the color slurring detecting operation is performed after the completion of continuous printing. The correction operation is performed regardless of the size of the detected color slurring, or the correction operation is not performed according to the condition to save on power and lessen the operation time. After the continuous printing, the color slurring detection and correction operation are not performed according to the condition to save on power consumption and lessen the operation time. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、光源から照射された光で感光体上に潜像を形成し、各異なるトナーにより現像し、それを被転写材に転写し定着して画像を形成するカラープリンターに関するものである。
【０００２】
【従来の技術】
従来、各色ごとに現像器と感光体を持つカラー画像形成装置では、連続印字の際に光学ユニット内に設置されたモータが発熱して光学の特性が変化したり、本体の各種モータや電気素子が発熱して本体内の温度が上昇することで、中間転写体を駆動させるローラの径が変化して中間転写体の周速度が変化したり、感光体ドラムの位置決め部材が熱膨張し感光体ドラムの位置がずれることで、色ずれが発生してくる。
【０００３】
これらは連続印字の途中で所定枚数に達すると、印字を中断させ色ずれの検知・補正動作を実施し、連続印字を再開する。これによって連続印字中の画像が色ズレのない安定したものとなる。
【０００４】
そして、上記の連続印字の途中での色ずれの検知・補正動作に加えて、連続印字が終了すると色ずれの検知・補正動作を実施して、いつでも安定して美しい画像を得ていた。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記従来の構成では、連続印字が終了する度に色ズレの検知動作と補正動作を実施する必要があり、これには時間と電力がかかる。特に検知動作には時間が掛かりユーザーに不満をもたらしていた。また、連続印字が終了した際に発生する色ズレ量がわずかであっても、色ズレの検知・補正動作をおこなっていた。
【０００６】
本出願に係る発明の目的は、連続印字の後の色ズレ検知動作及び補正動作を両方とも、あるいは片方のみを条件に応じて動作させない物である。これによって連続印字時後の色ズレ検知・補正動作に掛かる時間を短縮でき、これらに要される電力を省くことが出来る。
【０００７】
【課題を解決するための手段】
本出願に係る発明の目的を実現する第１の構成は、少なくとも、複数の感光体とこれに相対する帯電手段及び現像手段とトナー等を有するプロセスカートリッジ１０と、該感光体に画像形成させる光学系を有する複数の光学ユニット２０とを保持する容器筐体で形成されていて、順次画像を形成していくカラー画像形成装置において、中間転写ベルト３１を支持する駆動ローラ３２の上方に色ずれ検知装置１００が配置され、該光学ユニット２０は回折格子２４が自由に揺動するように構成されている。
【０００８】
前記光学ユニット２０は、光源から出たレーザー光が折り返しミラー２３によって反射され回折格子２４を経て感光体ドラム１２に照射される。回折格子２４は図示しないモータとギアユニットによって光路に対して略直角方向に作動することが可能となっている。これにより常に色ズレの補正が可能となる。
【０００９】
前記色ずれ検知装置１００は、投光部１０１と受光部１０２を備えており、投光部１０１から出た投射光１０１ａは中間転写ベルト３１上に照射される。投射光１０１ａは、前記中間転写体ベルト３１上に転写された色ずれを検知するための特殊なパターンに反射して反射光１０２ａとして受光部１０２で受光される。受光されたデータをもとに演算装置にて色ずれ量を算出して、前記光学ユニット２０内の前記回折格子２４を動作させて色ずれを補正する。
【００１０】
上記の構成によれば、連続印字後に色ズレ検知動作を実施して、所定の色ズレ量内であれば補正動作を実施しない、あるいは、ユーザーが補正動作を実行するか否かを選択可能になる。
【００１１】
また、連続印字の枚数に対応させて、最初に実施した連続印字後に色ズレ検知・補正動作を実施して検知した色ズレ量を本体内に記憶させておくことで、次回以降に略同枚数の連続印字が終了した際に、色ズレの検知動作を行うことなく、本体内に記憶されている色ズレ量に対応した分だけ補正動作が可能となる。
【００１２】
また、連続印字の開始前と終了後の温度変化を測定することで、所定の温度変化内であれば色ズレの検知・補正動作を行わない。
【００１３】
また、直前の連続印字終了時から次の印字指示までの時間経過が所定の時間内の場合で、且つ直前の連続印字終了時から次の印字指示までの温度変化が所定の温度変化内であれば色ズレの検知・補正動作を実施させない。
【００１４】
以上により、連続印字後の色ズレ検知動作や補正動作を条件に応じて動作させないことで、時間の短縮と省電力が可能な装置を提供できる。
【００１５】
【発明の実施の形態】
〔第１の実施例〕
図１から図９は、本発明の第１の実施の形態を示したものである。まず、図１により本発明の実施例が具現化されるカラー画像形成装置の一実施例について説明する。
【００１６】
本実施例のカラー画像形成装置は４色分のプロセスカートリッジ１０ｙ、１０ｍ、１０ｃ、１０ｋを対応する各現像形成ステーションに着脱可能であって、レーザー光を照射可能な光学ユニット２０ｙ、２０ｍ、２０ｃ、２０ｋ、中間転写体ユニット３０、被転写材搬送ユニット４０、および定着ユニット５０などを備えている。
【００１７】
各プロセスカートリッジ１０ｙ、１０ｍ、１０ｃ、１０ｋは同一構造とされ、それぞれ電子写真感光体である感光体ドラム１２、帯電手段１３、現像装置１４及びクリーニング装置１５が一体的に構成されている。
【００１８】
中間転写体ユニット３０は、無端ベルト体である中間転写ベルト３１、中間転写ベルト３１を回転可能に支持する３つのローラー駆動ローラ３２，テンションローラ３３，二次転写対向ローラ３４、各感光体ドラム１２に形成されたトナー像を中間転写ベルト３１に転写する一次転写ローラー３５、及び中間転写ベルト３１上に転写されたトナー像を更に被転写材ｐに転写する二次転写ローラー３６を備えている。被転写材搬送ユニット４０は、各給紙カセット４１あるいは給紙トレイ４２から非転写材ｐを二次転写領域に搬送するピックアップローラー４３、給紙ローラー４４、搬送ローラー４５、およびレジストローラー４６などを備えている。
【００１９】
定着ユニット５０は、定着ローラー５１および加圧ローラー５２を備え、被転写材ｐ上のトナー像に熱と圧を加えることで定着を行う。
【００２０】
上記構成において、まず１色目例えばブラックのプロセスカートリッジ１０ｋにおいて、感光体ドラム１２が帯電手段１３によって一様に帯電された後光学ユニット２０ｋから照射されたレーザー光２９によって潜像が形成され、この潜像が現像装置１４によって現像されてトナー像が形成される。
【００２１】
感光体ドラム１２上に形成されたトナー像は、一次転写ローラー３５の作用によって中間転写ベルト３１上に一次転写される。一次転写が終了した感光体ドラム１２はクリーニング装置１５によってクリーニングされ、次の画像形成に供される。
【００２２】
同様の画像形成工程がｙ、ｍ、ｃ用の各プロセスカートリッジ１０ｙ、１０ｍ、１０ｃにおいても行われて各色のトナー像が形成され、先に形成されたトナー像に順番に重ね転写される。
【００２３】
一方、被転写材ｐが給紙カセット４１または給紙トレイ４２から被転写材搬送ユニット４０によって２次転写領域に搬送され、２次転写ローラー３６の作用によって中間転写ベルト３１上に形成されたトナー像が被転写材ｐに転写される。トナー像を転写された被転写材ｐは定着ユニット５０に搬送され、定着ローラー５１と加圧ローラー５２のニップ部にてトナー像が定着され、排紙ローラー５５によって排紙トレイ５６上に排紙される。
【００２４】
次に図２と図３により、色ズレの検知・補正機構について説明する。
【００２５】
図２は光学ユニット２０の概略構成を示した断面図であり、２１が光学箱、２２が光源、２３が折り返しミラー、２４が回折格子である。
【００２６】
光源２２から出たレーザー光２９は折り返しミラー２３によって反射され回折格子２４を経て感光体ドラム１２に照射される。回折格子２４は、図示しない駆動モータやギアユニットを備えており、光路に対して略直角方向に作動することが可能となっている。これによって色ズレの補正が可能となる。
【００２７】
図３は色ズレ検知装置１００の概略構成を説明する図で、３１が中間転写ベルト、３２が駆動ローラ、１００が色ズレ検知装置を表す。
【００２８】
色ズレ検知装置１００は、中間転写ベルト３１を支持する駆動ローラ３２の図中上方に配置されている。駆動ローラ３２の回転軸３２ａと同軸上にローラ駆動ギア３６が固定されており、ローラ駆動ギア３６には図示しないモータなどの駆動源から駆動力を受けて回転するモータギア３７が係合している。これにより、駆動ローラ３２はモータからの駆動力によってモータギア３７、ローラ駆動ギア３６、回転軸３２ａを介して回転駆動される。
【００２９】
色ズレ検知装置１００は投光部１０１と受光部１０２を備えている。投光部１０１からの投射光１０１ａは中間転写ベルト３１を目標に投射される。中間転写ベルト３１上には感光体ドラム１２上に作像されたトナー像が転写され、中間転写ベルト３１は駆動ローラ３２によって作動し転写されたトナー像が投射光１０１ａの投射点を通過する。通常、中間転写ベルト３１はカーボンなどが含まれることで黒色をしているので、色ズレ検知装置１００から投射された投射光１０１ａは中間転写ベルト３１にあたるとその反射光１０２ａは光量が少なく検出されない。ここに前述したトナー像が通過すると投射光１０１ａはトナーに反射して反射光１０２ａとして受光部１０２で受光される。
【００３０】
受光されたデータをもとに、図示しない演算装置によって色ズレ量を検知する。検知した結果から色ズレ補正を実施し、必要であれば光学ユニット２０内の回折格子２４を動作させる。
【００３１】
ここで色ズレの検知・補正動作について説明する。最初に色ズレが判別出来る特殊なパターンを中間転写ベルト３１上に印字する。次にこの特殊なパターンを前記色ズレ検知装置１００によって検知して色ズレを検出する。そして電気的にレーザー光の照射する位置と発光するタイミングを調整したり、光学ユニット２０に設けられた回折格子２４を動作させたりして色ズレを補正する。最後に紙には転写せずに図示しないクリーニング装置によって中間転写ベルト３１上のトナー像を除去する。
【００３２】
次に連続印字時の途中の色ズレ検知・補正動作について説明する。連続印字時では光学ユニット２０はユニット内に設置された図示しないモータの回転により昇温したり、その他のモータ、定着ユニット５０、電気素子などの発熱により本体内の温度が上昇したりする。これにより光学ユニット２０の特性の変化、駆動ローラ３２径の変化による中間転写ベルト３１の速度変化や、感光体ドラム１２の位置決め部材（図示せず）の膨張による感光体ドラム１２の位置ズレなどによって、色ズレが発生する。
【００３３】
この色ズレを補正し常に安定した画像を得るために、例えば連続印字の途中に所定枚数に達した場合に、印字を中断し色ズレ検知・補正動作を実施する。色ズレの補正が完了した時点で連続印字を再開する。これによって連続印字中において色ズレのない美しい画像が得られる。
【００３４】
次に図４から図９により、本発明の特徴的動作である連続印字後の色ズレの検知・補正動作について説明する。
【００３５】
連続印字の途中で所定の枚数に達すると、印字を中断させ色ズレの検知動作を行い、補正を行う。補正が終了後、連続印字を再開する。そして連続印字が終了すると色ズレの検知動作を開始する。その後の補正動作について次の３つのパターンを説明する。
【００３６】
第１のパターンである図４では、連続印字終了後に検知した色ズレ量の大小に関わらず光学ユニット２０内に設置された図示しないモータを駆動させて必要な量だけ回折格子２４を動作させて色ズレを補正する。（通常モード）これにより常に色ズレの無い安定した画像を得ることができる。
【００３７】
第２のパターンである図５では、連続印字終了後に検知した色ズレ量が所定の値以下の場合には色ズレ補正を行わない。（省エネ、時間短縮モード）これにより光学ユニット２０内に設置された図示しないモータを駆動させて回折格子２４を動作させる電力と時間を省くことができる。なお検知した色ズレ量が所定の値以上の場合には、必要量だけ光学ユニット２０内に設置された図示しないモータを駆動させて回折格子２４を動作させ、色ズレを補正し色ズレの無い安定した画像を得ることが出来る。
【００３８】
第３のパターンである図６では、連続印字終了後に検知した色ズレ量が所定の値以下の場合には、図示しないオペレーションパネルあるいはパソコン等のモニターなどを介してユーザーに告知し、ユーザーが色ズレ補正を実施するか否かを選択可能な構成となっている。（ユーザー選択モード）これにより、色ズレ補正を実施しない場合には図示しない光学ユニット２０内に設置されたモータを駆動させて回折格子２４を動作させる電力と時間を省くことができ、かつユーザーの用途に応じた印字品質を提供可能となる。なお検知した色ズレ量が所定の値以上の場合には、必要量だけ光学ユニット２０内に設置された図示しないモータを駆動させて回折格子２４を動作させ、色ズレを補正し色ズレのない画像を得ることが出来る。
【００３９】
以上３つの実施例では、連続印字が終了した後に色ズレの検知をし、その後に光学ユニット２０内に設置された図示しないモータを駆動させて回折格子２４を動作させないことで省電力と時間短縮を図るものを説明した。次に、連続印字の終了後に色ズレの検知動作をさせずに省電力と時間短縮を図る３つのパターンについて説明する。
【００４０】
まず、図７ではＡ枚の連続印字の指示があったときに、連続印字の途中で所定の枚数に達すると、印字を中断させ色ズレの検知動作を行い、補正を行う。補正が終了後、連続印字を再開する。
【００４１】
そして連続印字が終了すると色ズレの検知動作を開始して検知した色ズレ量Ｂだけ、回折格子２４を動作させて色ズレを補正する。この色ズレ検出量Ｂを連続印字の指示枚数Ａ枚と対応させて本体内に記憶させておく。その後、ほぼ同枚数のＡ’枚の連続印字を実施し、連続印字が終了した際に色ズレ検知動作を実施せず、記憶させておいた色ズレ補正量Ｂだけ色ズレを補正する。これにより、例えば５００枚の連続印字後の色ズレ検知動作が最初の１回だけですみ、その後のほぼ同一枚数、例えば４５０枚から５５０枚の連続印字後に色ズレ検知動作を行う必要はなく、省電力と時間の短縮ができる。
【００４２】
次に、図１に示す６０は温度測定装置を示し本体内の温度を測定できる。図８では温度測定装置６０を用いて連続印字開始前の機体内の温度を測定しておく。この温度をＣ１とする。
【００４３】
次に連続印字の途中で所定の枚数に達すると、印字を中断させ色ズレの検知動作を行い、回折格子２４を動作させて補正を行う。補正が終了後、連続印字を再開する。そして連続印字が終了すると、温度測定装置６０にて再び機体内の温度を測定する。この温度をＣ２とする。そして連続印字開始前の温度Ｃ１から連続印字終了後の温度Ｃ２の温度差Ｃ２−Ｃ１が所定の温度以下の場合には、色ずれの検地・補正を動作させない。これによって、色ずれの検知・補正動作に必要な電力を省けてかつ時間の短縮となる。なお、温度差Ｃ２−Ｃ１が所定の値以上の場合には、色ずれの検地・補正動作を実施させ色ズレの無い画像を得ることができる。
【００４４】
次に、図１に示す６０は温度測定装置を示し本体内の温度を測定できる。また、図示しない本体のコントローラには時計機能が備わっており、常に時間の経過をモニタできる。
【００４５】
連続印字の途中で所定の枚数に達すると、印字を中断させ色ズレの検知動作を行い、光学ユニット２０内に設置された図示しないモータによって回折格子を動作させて補正を行う。補正が終了後、連続印字を再開し所定の枚数の印字が終了して連続印字を終了する。このとき、時計機能にて時刻、温度測定装置６０にて機内の温度を測定して記憶させておく。記憶させた時刻をＤ１、温度をＥ１とする。
【００４６】
連続印字が終了した後には、光学ユニット２０や機体内の温度は降下していく。それに伴い、光学特性や、中間転写ベルト３１の駆動ローラ３２の径の変化に伴う周速度の変化、感光体ドラム１２の位置決め部材（図示せず）の収縮による感光体ドラム１０の位置ズレ、などにより色ズレが変化していく。
【００４７】
そこで次回の印字指示があったときの時刻をＤ２、機内の温度をＥ２とすると、最初に先ほどの連続印字終了時に記憶させた時刻Ｄ１から計算して、直前の連続印字終了時からの時間経過Ｄ２−Ｄ１が所定の時間内か時間外かを判断する。次に所定の時間内ならば先ほどの連続印字終了時に記憶させた機内の温度Ｅ１から計算して、直前の連続印字終了時からの温度変化Ｅ２−Ｅ１が所定の温度変化内であれば色ズレの検知・補正動作を実施させない。これにより、色ズレ検知・補正を動作させるための電力を省けてかつ、時間の短縮になる。なお機内の温度変化Ｅ２−Ｅ１が所定の値を越えている場合には、色ズレの検知・補正動作を実行させて色ズレのない画像を出力できるようになる。また、直前の連続印字終了時からの時間経過Ｄ２−Ｄ１が所定の時間外ならば、機内の温度変化には関係なく、色ズレの検知・補正動作を実施させて色ズレの無い画像を出力できる。
【００４８】
なお、上記実施例では色ズレ検知装置１００が駆動ローラー３２の上方に配置されていると説明したが、これに限定されず画像形成に支障を与えずに、色ズレを検知できれば配置場所にこだわらない。
【００４９】
また、上記実施例では光学ユニット２０に設置された回折格子２４を光路と略直角方向に動作させて色ズレを補正すると説明したが、例えば折り返しミラー２３の角度や位置を変化させて色ズレを補正してもよい。
【００５０】
また、上記実施例では連続印字の途中での色ずれ検知・補正動作について、所定枚数に達すると連続印字を中断し色ずれの検知動作、補正動作を実施して連続印字を再開すると説明したが、これに限定せず、例えば温度測定装置６０にて機内の温度を測定し、所定の温度に達したら連続印字を中断し色ずれの検知・補正動作を実施してもよい。
【００５１】
また、上記実施例では連続印字の途中での色ずれ検知・補正動作について、所定枚数に達すると連続印字を中断し色ずれの検知動作、補正動作を実施して連続印字を再開すると説明したが、予め印字枚数毎に補正する量が決まっていて、所定の枚数に達すると色ズレの検知をせずに補正動作のみを実施してもかまわない。
【００５２】
また、上記実施例を説明ずる図では機内温度を測定する温度測定装置６０が駆動ローラ３２の上方に設置されているように記したが、これに限定されず機内の温度変化に対する色ズレの変化が一対一で判別できれば設置場所は問わない。
【００５３】
【発明の効果】
以上説明したように、本出願に係る発明によれば、連続印字後に色ズレ検知動作を実施して、所定の色ズレ量内であれば補正動作を実施しない、あるいは、ユーザーが補正動作を実行するか否かを選択可能になる。
【００５４】
また、連続印字の枚数に対応させて、最初に実施した連続印字後に色ズレ検知・補正動作を実施して検知した色ズレ量を本体内に記憶させておくことで、次回以降にほぼ同枚数の連続印字が終了した際に、色ズレの検知動作を行うことなく、本体内に記憶されている色ズレ量に対応した分だけ補正動作が可能となる。
【００５５】
また、連続印字の開始前と終了後の温度変化を測定することで、所定の温度変化内であれば色ズレの検知・補正動作を行わない。
【００５６】
また、直前の連続印字終了時から次の印字指示までの時間経過が所定の時間内の場合で、且つ直前の連続印字終了時から次の印字指示までの温度変化が所定の温度変化内であれば色ズレの検知・補正動作を実施させない。
【００５７】
以上により、連続印字後の色ズレ検知動作や補正動作を条件に応じて動作させないことで、時間の短縮と省電力が可能な装置を提供できる。
【図面の簡単な説明】
【図１】カラー画像形成装置を説明する図。
【図２】光学ユニットを説明する図。
【図３】色ずれ検知装置を説明する図。
【図４】連続印字後の色ずれ検知・補正動作を説明する図。
【図５】連続印字後の色ずれ検知・補正動作を説明する図。
【図６】連続印字後の色ずれ検知・補正動作を説明する図。
【図７】連続印字後の色ずれ検知・補正動作を説明する図。
【図８】連続印字後の色ずれ検知・補正動作を説明する図。
【図９】連続印字後の色ずれ検知・補正動作を説明する図。
【符号の説明】
１０　プロセスカートリッジ
１２　感光体ドラム
２０　光学ユニット
２４　回折格子
３１　中間転写ベルト
３２　駆動ローラー
６０　温度測定装置
１００　色ズレ検知装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a color printer that forms a latent image on a photoreceptor with light emitted from a light source, develops the latent image with different toners, transfers the latent image to a material to be transferred, and fixes the image to form an image.
[0002]
[Prior art]
Conventionally, in a color image forming apparatus having a developing unit and a photoreceptor for each color, during continuous printing, a motor installed in an optical unit generates heat to change optical characteristics, and various types of motors and electric elements in the main body. When the temperature inside the main body rises due to heat generation, the diameter of the roller that drives the intermediate transfer body changes, the peripheral speed of the intermediate transfer body changes, and the positioning member of the photoconductor drum thermally expands, causing the photoconductor to expand. When the position of the drum is shifted, a color shift occurs.
[0003]
When the number of sheets reaches a predetermined number in the middle of continuous printing, printing is interrupted, color shift detection / correction operation is performed, and continuous printing is restarted. As a result, the image during continuous printing becomes stable without color shift.
[0004]
Then, in addition to the operation for detecting and correcting the color misregistration in the middle of the continuous printing, the operation for detecting and correcting the color misregistration is performed when the continuous printing is completed, so that a stable and beautiful image is always obtained.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, it is necessary to perform the color misregistration detection operation and the correction operation each time the continuous printing is completed, which requires time and power. In particular, the detection operation was time-consuming and was causing user dissatisfaction. Further, even if the amount of color misregistration generated when continuous printing is completed is small, the operation of detecting and correcting color misregistration has been performed.
[0006]
An object of the invention according to the present application is to prevent both the color misregistration detection operation and the correction operation after continuous printing or only one of them from operating according to conditions. As a result, the time required for the color misregistration detection / correction operation after continuous printing can be reduced, and the power required for these operations can be saved.
[0007]
[Means for Solving the Problems]
A first configuration for realizing the object of the invention according to the present application is a process cartridge 10 including at least a plurality of photoconductors, a charging unit and a developing unit, a toner, and the like opposed thereto, and an optical device for forming an image on the photoconductor. In a color image forming apparatus that is formed of a container housing that holds a plurality of optical units 20 having a system and sequentially forms an image, a color shift detection is performed above a driving roller 32 that supports an intermediate transfer belt 31. The device 100 is arranged and the optical unit 20 is configured such that the diffraction grating 24 swings freely.
[0008]
The optical unit 20 irradiates the photosensitive drum 12 with laser light emitted from a light source, reflected by a folding mirror 23 and passing through a diffraction grating 24. The diffraction grating 24 can be operated in a direction substantially perpendicular to the optical path by a motor and a gear unit (not shown). As a result, color shift can always be corrected.
[0009]
The color misregistration detection device 100 includes a light projecting unit 101 and a light receiving unit 102, and the projection light 101 a emitted from the light projecting unit 101 is irradiated onto the intermediate transfer belt 31. The projection light 101a is reflected by a special pattern for detecting color misregistration transferred onto the intermediate transfer belt 31 and received by the light receiving unit 102 as reflected light 102a. The color shift amount is calculated by an arithmetic unit based on the received data, and the color shift is corrected by operating the diffraction grating 24 in the optical unit 20.
[0010]
According to the above configuration, the color misregistration detecting operation is performed after continuous printing, and the correction operation is not performed if the color misregistration amount is within the predetermined amount, or the user can select whether to perform the correction operation. Become.
[0011]
In addition, the color misregistration detection / correction operation is performed after the first continuous printing, and the detected color misregistration amount is stored in the main unit in accordance with the number of continuous prints. When the continuous printing is completed, the correction operation can be performed by an amount corresponding to the color shift amount stored in the main body without performing the color shift detecting operation.
[0012]
Further, by measuring the temperature change before and after the end of the continuous printing, the color shift detection / correction operation is not performed within the predetermined temperature change.
[0013]
Also, if the time elapsed from the end of the previous continuous printing to the next printing instruction is within a predetermined time, and the temperature change from the end of the previous continuous printing to the next printing instruction is within the predetermined temperature change. In this case, the operation for detecting and correcting color misregistration is not performed.
[0014]
As described above, a device capable of reducing time and saving power can be provided by not operating the color misregistration detection operation and the correction operation after continuous printing according to the conditions.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
[First embodiment]
1 to 9 show a first embodiment of the present invention. First, an embodiment of a color image forming apparatus in which an embodiment of the present invention is embodied will be described with reference to FIG.
[0016]
In the color image forming apparatus of the present embodiment, the process cartridges 10y, 10m, 10c, and 10k for four colors can be detachably attached to the corresponding development forming stations, and optical units 20y, 20m, and 20c that can irradiate laser light. 20k, an intermediate transfer body unit 30, a transfer material transporting unit 40, a fixing unit 50, and the like.
[0017]
Each of the process cartridges 10y, 10m, 10c, and 10k has the same structure, and a photosensitive drum 12, which is an electrophotographic photosensitive member, a charging unit 13, a developing device 14, and a cleaning device 15, are integrally formed.
[0018]
The intermediate transfer unit 30 is an endless belt, an intermediate transfer belt 31, three roller driving rollers 32 rotatably supporting the intermediate transfer belt 31, a tension roller 33, a secondary transfer opposing roller 34, and each of the photosensitive drums 12. A primary transfer roller 35 for transferring the toner image formed on the intermediate transfer belt 31 to the toner image formed on the intermediate transfer belt 31, and a secondary transfer roller 36 for further transferring the toner image transferred on the intermediate transfer belt 31 to the transfer material p. The transfer target material transport unit 40 includes a pickup roller 43, a feed roller 44, a transport roller 45, a registration roller 46, and the like that transport the non-transfer material p from each paper feed cassette 41 or the paper feed tray 42 to the secondary transfer area. Have.
[0019]
The fixing unit 50 includes a fixing roller 51 and a pressure roller 52, and performs fixing by applying heat and pressure to the toner image on the transfer material p.
[0020]
In the above configuration, first, in the process cartridge 10k of the first color, for example, black, the photosensitive drum 12 is uniformly charged by the charging means 13 and then a latent image is formed by the laser light 29 emitted from the optical unit 20k. The image is developed by the developing device 14 to form a toner image.
[0021]
The toner image formed on the photosensitive drum 12 is primarily transferred onto the intermediate transfer belt 31 by the action of the primary transfer roller 35. The photoconductor drum 12 after the primary transfer is cleaned by the cleaning device 15 and is used for the next image formation.
[0022]
A similar image forming process is also performed in each of the process cartridges 10y, 10m, and 10c for y, m, and c to form a toner image of each color, which is sequentially transferred to the previously formed toner image.
[0023]
On the other hand, the transfer material p is transported from the paper feed cassette 41 or the paper feed tray 42 to the secondary transfer area by the transfer material transport unit 40, and the toner formed on the intermediate transfer belt 31 by the operation of the secondary transfer roller 36. The image is transferred to the transfer material p. The transfer material p to which the toner image has been transferred is conveyed to the fixing unit 50, where the toner image is fixed at the nip portion between the fixing roller 51 and the pressure roller 52, and is discharged onto the discharge tray 56 by the discharge roller 55. Is done.
[0024]
Next, a color misregistration detection / correction mechanism will be described with reference to FIGS.
[0025]
FIG. 2 is a sectional view showing a schematic configuration of the optical unit 20, in which 21 is an optical box, 22 is a light source, 23 is a folding mirror, and 24 is a diffraction grating.
[0026]
Laser light 29 emitted from the light source 22 is reflected by the turning mirror 23 and is irradiated on the photosensitive drum 12 via the diffraction grating 24. The diffraction grating 24 includes a drive motor and a gear unit (not shown), and can operate in a direction substantially perpendicular to the optical path. Thereby, the color shift can be corrected.
[0027]
FIG. 3 is a view for explaining a schematic configuration of the color misregistration detecting device 100. Reference numeral 31 denotes an intermediate transfer belt, 32 denotes a driving roller, and 100 denotes a color misregistration detecting device.
[0028]
The color misregistration detecting device 100 is disposed above a driving roller 32 that supports the intermediate transfer belt 31 in the drawing. A roller drive gear 36 is fixed coaxially with the rotation shaft 32a of the drive roller 32, and a motor gear 37 that rotates by receiving a driving force from a drive source such as a motor (not shown) is engaged with the roller drive gear 36. . Thus, the driving roller 32 is driven to rotate by the driving force from the motor via the motor gear 37, the roller driving gear 36, and the rotating shaft 32a.
[0029]
The color misregistration detection device 100 includes a light projecting unit 101 and a light receiving unit 102. The projection light 101a from the light projection unit 101 is projected on the intermediate transfer belt 31 as a target. The toner image formed on the photosensitive drum 12 is transferred onto the intermediate transfer belt 31, and the intermediate transfer belt 31 is operated by the drive roller 32, and the transferred toner image passes through the projection point of the projection light 101a. Normally, since the intermediate transfer belt 31 is black due to the inclusion of carbon or the like, when the projection light 101a projected from the color misregistration detection device 100 hits the intermediate transfer belt 31, the reflected light 102a has a small amount of light and is not detected. . When the above-described toner image passes here, the projection light 101a is reflected by the toner and is received by the light receiving unit 102 as reflected light 102a.
[0030]
Based on the received data, the amount of color misregistration is detected by an arithmetic unit (not shown). The color shift is corrected based on the detected result, and the diffraction grating 24 in the optical unit 20 is operated if necessary.
[0031]
Here, the operation of detecting and correcting a color shift will be described. First, a special pattern on which the color shift can be determined is printed on the intermediate transfer belt 31. Next, the special pattern is detected by the color shift detecting device 100 to detect a color shift. Then, the position where the laser light is irradiated and the timing at which the light is emitted are electrically adjusted, and the color shift is corrected by operating the diffraction grating 24 provided in the optical unit 20. Finally, the toner image on the intermediate transfer belt 31 is removed by a cleaning device (not shown) without transferring to the paper.
[0032]
Next, a description will be given of an operation for detecting and correcting color misregistration during continuous printing. During continuous printing, the temperature of the optical unit 20 rises due to rotation of a motor (not shown) installed in the unit, and the temperature inside the main body rises due to heat generated by other motors, the fixing unit 50, electric elements, and the like. As a result, a change in the characteristics of the optical unit 20, a change in the speed of the intermediate transfer belt 31 due to a change in the diameter of the driving roller 32, a displacement of the photosensitive drum 12 due to expansion of a positioning member (not shown) of the photosensitive drum 12, and the like. Color shift occurs.
[0033]
In order to correct this color shift and always obtain a stable image, for example, when a predetermined number of sheets is reached during continuous printing, printing is interrupted and a color shift detection / correction operation is performed. Continuous printing is resumed when the color shift correction is completed. As a result, a beautiful image without color shift during continuous printing can be obtained.
[0034]
Next, with reference to FIGS. 4 to 9, the operation of detecting and correcting a color shift after continuous printing, which is a characteristic operation of the present invention, will be described.
[0035]
When a predetermined number of sheets is reached during continuous printing, printing is interrupted, a color shift detection operation is performed, and correction is performed. After the correction is completed, continuous printing is restarted. Then, when the continuous printing is completed, a color shift detecting operation is started. The following three patterns will be described for the subsequent correction operation.
[0036]
In FIG. 4, which is the first pattern, the diffraction grating 24 is operated by a required amount by driving a motor (not shown) provided in the optical unit 20 irrespective of the magnitude of the color misregistration detected after the continuous printing. Correct the color shift. (Normal mode) This makes it possible to always obtain a stable image without color shift.
[0037]
In FIG. 5, which is the second pattern, if the color shift amount detected after the end of continuous printing is equal to or smaller than a predetermined value, the color shift correction is not performed. (Energy saving, time reduction mode) By this means, it is possible to save power and time for operating the diffraction grating 24 by driving a motor (not shown) provided in the optical unit 20. When the detected color shift amount is equal to or more than a predetermined value, the diffraction grating 24 is operated by driving a motor (not shown) provided in the optical unit 20 by a required amount, and the color shift is corrected and there is no color shift. A stable image can be obtained.
[0038]
In FIG. 6, which is the third pattern, when the color misregistration amount detected after the end of the continuous printing is equal to or less than a predetermined value, the user is notified via an operation panel (not shown) or a monitor of a personal computer or the like, and the user is allowed to perform color adjustment. It is configured to be able to select whether or not to perform the displacement correction. (User selection mode) By this means, when color misregistration correction is not performed, it is possible to save power and time for operating the diffraction grating 24 by driving a motor installed in the optical unit 20 (not shown), and It is possible to provide printing quality according to the application. If the detected color shift amount is equal to or more than a predetermined value, the diffraction grating 24 is operated by driving a motor (not shown) provided in the optical unit 20 by a required amount, and the color shift is corrected to eliminate the color shift. Images can be obtained.
[0039]
In the above three embodiments, the color misregistration is detected after the continuous printing is completed, and then the motor (not shown) installed in the optical unit 20 is driven to operate the diffraction grating 24, thereby saving power and reducing time. What was aimed at was explained. Next, three patterns for saving power and reducing time without performing a color shift detection operation after the end of continuous printing will be described.
[0040]
First, in FIG. 7, when an instruction for continuous printing of A sheets is given, if a predetermined number of sheets are reached during continuous printing, printing is interrupted, a color shift detection operation is performed, and correction is performed. After the correction is completed, continuous printing is restarted.
[0041]
When the continuous printing is completed, a color shift detection operation is started, and the color shift is corrected by operating the diffraction grating 24 by the detected color shift amount B. The color misregistration detection amount B is stored in the main body in correspondence with the designated number A of the continuous printing. After that, continuous printing of substantially the same number of A 'sheets is performed, and when the continuous printing is completed, the color shift detection operation is not performed, and the color shift is corrected by the stored color shift correction amount B. Thus, for example, the color misregistration detection operation after continuous printing of 500 sheets only needs to be performed once at the first time, and it is not necessary to perform the color misregistration detection operation after substantially continuous printing of approximately the same number of sheets, for example, 450 to 550 sheets. Power saving and time reduction can be achieved.
[0042]
Next, reference numeral 60 shown in FIG. 1 indicates a temperature measuring device, which can measure the temperature inside the main body. In FIG. 8, the temperature inside the machine before the start of continuous printing is measured using the temperature measuring device 60. This temperature is defined as C1.
[0043]
Next, when the predetermined number of sheets is reached during the continuous printing, the printing is interrupted, a color shift detecting operation is performed, and the diffraction grating 24 is operated to perform correction. After the correction is completed, continuous printing is restarted. Then, when the continuous printing is completed, the temperature inside the machine is measured again by the temperature measuring device 60. This temperature is defined as C2. If the temperature difference C2-C1 between the temperature C1 before the start of continuous printing and the temperature C2 after the end of continuous printing is equal to or lower than a predetermined temperature, the detection and correction of color misregistration is not performed. As a result, the power required for the operation of detecting and correcting the color misregistration can be saved and the time can be reduced. When the temperature difference C2-C1 is equal to or larger than a predetermined value, a color misregistration detection and correction operation can be performed to obtain an image without color shift.
[0044]
Next, reference numeral 60 shown in FIG. 1 indicates a temperature measuring device, which can measure the temperature inside the main body. The controller of the main body (not shown) has a clock function, and can constantly monitor the passage of time.
[0045]
When a predetermined number of sheets is reached during continuous printing, printing is interrupted to detect a color shift, and correction is performed by operating a diffraction grating by a motor (not shown) installed in the optical unit 20. After the correction is completed, continuous printing is restarted, printing of a predetermined number of sheets is completed, and continuous printing is completed. At this time, the time and the temperature inside the device are measured by the clock function and the temperature measuring device 60 and stored. Let D1 be the stored time and E1 be the temperature.
[0046]
After the end of the continuous printing, the temperature inside the optical unit 20 and the inside of the apparatus decreases. Accordingly, changes in the optical characteristics, changes in the peripheral speed due to changes in the diameter of the drive roller 32 of the intermediate transfer belt 31, changes in the position of the photosensitive drum 10 due to contraction of a positioning member (not shown) of the photosensitive drum 12, and the like. The color shift changes.
[0047]
Then, assuming that the time when the next printing instruction is issued is D2 and the temperature in the machine is E2, the time is calculated from the time D1 stored at the end of the previous continuous printing first, and the time elapsed from the end of the immediately preceding continuous printing is calculated. It is determined whether D2-D1 is within the predetermined time or outside the predetermined time. Next, if within a predetermined time, calculation is performed from the in-machine temperature E1 stored at the end of the previous continuous printing, and if the temperature change E2-E1 from the immediately preceding continuous printing end is within the predetermined temperature change, the color shift is performed. Detection / correction operation is not performed. This saves power for operating the color misregistration detection / correction and shortens the time. If the temperature change E2-E1 in the apparatus exceeds a predetermined value, a color shift detection / correction operation is executed to output an image without color shift. If the time lapse D2-D1 from the end of the immediately preceding continuous printing is outside the predetermined time, the color shift detection / correction operation is performed and an image free of color shift is output irrespective of the temperature change in the apparatus. it can.
[0048]
In the above embodiment, the color misregistration detection device 100 is described as being disposed above the drive roller 32. However, the present invention is not limited to this. Absent.
[0049]
Further, in the above-described embodiment, it has been described that the color shift is corrected by operating the diffraction grating 24 provided in the optical unit 20 in a direction substantially perpendicular to the optical path. However, for example, the angle and the position of the folding mirror 23 are changed to reduce the color shift. It may be corrected.
[0050]
Further, in the above-described embodiment, it has been described that, regarding the color misregistration detection / correction operation in the middle of the continuous printing, the continuous printing is interrupted when the predetermined number of sheets is reached, the color misregistration detection operation and the correction operation are performed, and the continuous printing is resumed. However, the present invention is not limited to this. For example, the temperature inside the apparatus may be measured by the temperature measuring device 60, and when the temperature reaches a predetermined temperature, the continuous printing may be interrupted and the operation of detecting and correcting a color shift may be performed.
[0051]
Further, in the above-described embodiment, it has been described that, regarding the color misregistration detection / correction operation in the middle of the continuous printing, the continuous printing is interrupted when the predetermined number of sheets is reached, the color misregistration detection operation and the correction operation are performed, and the continuous printing is resumed. However, the correction amount is determined in advance for each number of printed sheets, and when the number of printed sheets reaches the predetermined number, only the correction operation may be performed without detecting the color shift.
[0052]
In the drawings describing the above-described embodiment, the temperature measuring device 60 for measuring the temperature inside the apparatus is described as being installed above the drive roller 32. However, the present invention is not limited to this. Is not limited as long as it can be determined one-to-one.
[0053]
【The invention's effect】
As described above, according to the invention of the present application, the color misregistration detecting operation is performed after continuous printing, and the correction operation is not performed if the color misregistration is within a predetermined amount, or the user performs the correction operation. It is possible to select whether or not to do so.
[0054]
In addition, the color misregistration detection / correction operation is performed after the first continuous printing, and the detected color misregistration amount is stored in the main unit according to the number of continuous prints. When the continuous printing is completed, the correction operation can be performed by an amount corresponding to the color shift amount stored in the main body without performing the color shift detecting operation.
[0055]
Further, by measuring the temperature change before and after the continuous printing, the color shift detection / correction operation is not performed within a predetermined temperature change.
[0056]
Also, if the time elapsed from the end of the previous continuous printing to the next printing instruction is within a predetermined time, and the temperature change from the end of the previous continuous printing to the next printing instruction is within the predetermined temperature change. In this case, the operation for detecting and correcting color misregistration is not performed.
[0057]
As described above, a device capable of reducing time and saving power can be provided by not operating the color misregistration detection operation and the correction operation after continuous printing according to the conditions.
[Brief description of the drawings]
FIG. 1 illustrates a color image forming apparatus.
FIG. 2 illustrates an optical unit.
FIG. 3 is a diagram illustrating a color misregistration detection device.
FIG. 4 is a diagram illustrating a color misregistration detection / correction operation after continuous printing.
FIG. 5 is a diagram illustrating a color misregistration detection / correction operation after continuous printing.
FIG. 6 is a diagram illustrating a color misregistration detection / correction operation after continuous printing.
FIG. 7 is a diagram illustrating a color misregistration detection / correction operation after continuous printing.
FIG. 8 is a diagram illustrating a color misregistration detection / correction operation after continuous printing.
FIG. 9 is a diagram illustrating a color misregistration detection / correction operation after continuous printing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Process cartridge 12 Photoreceptor drum 20 Optical unit 24 Diffraction grating 31 Intermediate transfer belt 32 Driving roller 60 Temperature measuring device 100 Color shift detecting device

Claims

It is formed of a container housing that holds a plurality of photoconductors, a process cartridge having a charging unit and a developing unit opposed thereto, a toner, and the like, and a plurality of optical units having an optical system for forming an image on the photoconductors. In a color image forming apparatus that sequentially forms images,
During continuous printing, a part of the optical unit is operated to perform color misregistration correction, and when a predetermined number of continuous printing is completed, the color misregistration amount is detected, and the optical unit is controlled regardless of the detected color misregistration amount. A color image forming apparatus, wherein the color shift correction is performed by operating the part, and the color shift correction is not performed according to conditions.

2. A printing method according to claim 1, wherein, when printing of a predetermined number of sheets is completed and color shift amount is detected in continuous printing, if the detected color shift amount is within a predetermined value, color shift correction is not performed. The color image forming apparatus as described in the above.

When the color misregistration amount is detected after printing of a predetermined number of sheets has been completed in continuous printing, if the detected color misregistration amount is within a predetermined value, the user must select whether or not to perform color misregistration correction. 2. The color image forming apparatus according to claim 1, wherein the color image forming apparatus is capable of performing the following.

It is formed of a container housing that holds a plurality of photoconductors, a process cartridge having a charging unit and a developing unit opposed thereto, a toner, and the like, and a plurality of optical units having an optical system for forming an image on the photoconductors. In a color image forming apparatus that sequentially forms images,
During the continuous printing, a part of the optical unit is operated to perform color misregistration correction, and when the printing of a predetermined number of sheets is completed and the color misregistration amount is detected and the color misregistration correction is performed, the detected color misregistration amount is calculated. A color image forming apparatus characterized by being stored in a main body in association with the number of continuous prints.

If the number of continuous prints matches the number of continuous prints stored in the main body with a deviation within a predetermined range, the color shift amount stored in the main body when the continuous printing is completed is corrected for color shift. 6. The color image forming apparatus according to claim 5, wherein color shift correction is performed as an amount.

It is formed of a container housing that holds a plurality of photoconductors, a process cartridge having a charging unit and a developing unit opposed thereto, a toner, and the like, and a plurality of optical units having an optical system for forming an image on the photoconductors. In a color image forming apparatus that sequentially forms images,
During continuous printing, a part of the optical unit is operated to perform color misregistration correction, and when printing of a predetermined number of sheets is completed, a temperature measurement device installed in the device detects a temperature change in the device from before the start of printing. A color image forming apparatus characterized in that detection and correction of an amount of color misregistration are not performed when a measured temperature change is not more than a predetermined temperature change.

It is formed of a container housing that holds a plurality of photoconductors, a process cartridge having a charging unit and a developing unit opposed thereto, a toner, and the like, and a plurality of optical units having an optical system for forming an image on the photoconductors. In a color image forming apparatus that sequentially forms images,
During continuous printing, a part of the optical unit is operated to perform color misregistration correction, and when a next printing instruction is given after printing a predetermined number of sheets, a controller having a clock function installed in the apparatus is provided. As a result of measuring the time change at, the temperature change within the device from the end of the last continuous printing is measured within a predetermined time from the end of the previous continuous printing and the temperature measuring device installed in the device. A color image forming apparatus characterized in that detection and correction of a color shift amount is not performed within a predetermined temperature change.

8. The color image forming apparatus according to claim 1, wherein the means for performing correction after detecting the amount of color shift is performed by operating a diffraction grating lens in the optical unit.