JP2004333962A - Cleaning unit, image-forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: satisfactory cleaning performance to a spherical small-diameter toner is not ensured only by applying vibration to a cleaning blade. <P>SOLUTION: A cleaning blade 20 to which vibration is applied in the cleaning unit 16 comprises a blade member 21, a vibration member 22 to which the blade member 21 is attached, a vibration applying means 23 attached to the vibration member 22, and a driving circuit 28 which drives the vibration applying means 23 according to a driving signal Pv with a resonance frequency of the blade member 21 and an image carrier 11 as a driving frequency, whereby a vibration amount of the blade member 21 is secured and cleaning performance is improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１５０】
（転写率評価）
転写率の評価（測定）には、像担持体表面にべたの画像を出力している途中で、動作を止め、現像部と転写部との間、及び転写クリーニング部との間のトナー像をスコッチテープ（住友３Ｍ株式会社製、商品名）で白い紙に転写させて、それをマクベス反射濃度計ＲＤ５１４型（商品名）で測定した。
【０１５１】
このとき、
現像部―転写部間のテープ濃度：Ｄｄｔ
転写部―クリーニング部間のテープ濃度：Ｄｔｃ
白い紙にスコッチテープを転写しただけの濃度：Ｄｒｅｆ
とし、転写効率を、次の（１）式で算出した。
【０１５２】
【数１】

【０１５３】
（クリーニング性評価）
クリーニング性評価についても、先の転写率と同じように、スコッチテープを使って評価した。
像担持体である感光体表面上の転写工程後のトナー（転写残留トナー）をスコッチテープ（住友３Ｍ株式会社製、商品名）で白い紙に転写させて、それを同じようにマクベス反射濃度計ＲＤ５１４型（商品名）で測定し、ブランク（白い紙にスコッチテープだけを貼ったもの）との差が、０．０１以下のものを良好（評価結果の表では「○」と記載）とし、それを超えるもの（濃度が高いもの）をＮＧ（不良）とした。
【０１５４】
実際の出力は、感光体上に付着量が０．１ｍｇ／ｃｍ^２となるような画像パターンを用意し、これをＡ３用紙縦方向で５００００枚分出力させる。５００００枚の出力が終了した段階で、先の転写率、クリーニング率の測定方法で示したように、べた画像となるような画像パターンを途中まで出力させ評価した。
【０１５５】
（共振周波数の測定）
図９に示すように、共振周波数を診るための振動計測装置４１を配置し、この振動計測装置４１の出力信号を振動解析用パソコン４２に取り込んだ。この振動計測装置４１は、レーザドップラ測定と呼ばれる測定原理で振動時の周波数特性を計測する。実際に使用したレーザドップラ振動計は、次のとおりである。
レーザドップラ振動計 ： （ピーアイ）ポリテック社製
レーザドップラ変位計 ＯＦＶ−３０３（商品名）
【０１５６】
そして、振動解析用パソコン５２の振動解析ソフトによって、ＦＦＴ解析を行うことによって、どの周波数に共振周波数があるか測定した。
【０１５７】
共振周波数を検知測定する時間を短縮するために、圧電素子に印加する波形としてある程度の振幅を持ったノイズを入力することがある。通常のクリーニング動作時は正弦波や矩形波を入力して駆動させているが、共振周波数を検知する場合にはノイズ（ホワイトノイズを呼ばれていることが多い）を入力する。
【０１５８】
（摩擦抵抗力と共振周波数）
上述したレーザドップラ振動計を含めた画像形成装置において、意図的に摩擦抵抗力を変化させたときの共振周波数の変化について説明する。
摩擦抵抗力の測定装置を実際の画像形成装置に組み込んで、ブレードと像担持体との摩擦抵抗力を直接測定することは困難である。そこで、ここでは、比較的測定が容易な像担持体の摩擦係数、あるいは、像担持体の回転トルクに基づいて加振手段の駆動周波数を設定制御する構成について説明する。なお、摩擦係数、トルクともに摩擦抵抗力と相関があり、根本的な意味では２つとも同値である。
【０１５９】
（１）感光体（像担持体）摩擦係数
初期の感光体摩擦係数の値を測定し（紙に対するオイラーベルト法）、これに対して図３に示す加振クリーニングブレード２０を一定の条件下（ホワイトノイズの振幅量が同じ）で駆動させたときの共振周波数の測定結果を図１０に示している。
【０１６０】
この図１０に示すように、２４ｋＨｚ付近（このときの正確な周波数を周波数ｂとする。）に振動変位量が大きくなる共振周波数を持つことが分かる。しかし、感光体摩擦係数の違いにより、その変位が最大の周波数が１ｋＨｚ程度の幅（周波数ａ、ｂ、ｃ）で変化していることが分かる。この原因についての詳細は未だ明らかではないが、感光体の摩擦係数が上がることによって、ブレード先端であって、クリーニングを行うニップ部が下流側に持っていかれ、結果的に圧電素子の駆動条件が同じでも、ブレード、感光体との組み合わせで共振周波数を変化させるため、このような結果になったと推測される。
【０１６１】
次に、各摩擦係数の値に対して、先に得られた共振周波数を駆動周波数とし、波形として正弦波を入力したときの感光体上のクリーニング性を判定した結果と、周波数ｂで固定して、感光体摩擦係数の値だけを変化させたときの結果を合わせて表１に示している。
【０１６２】
【表１】

【０１６３】
この表１によれば、感光体摩擦係数が変化しても、そのときに発生する共振周波数で圧電素子を駆動させればクリーニング性は良好であるが、感光体摩擦係数が変化しても固定の周波数で駆動させれば、クリーニング性が良好にはならないことが分かる。
【０１６４】
この原因としては、上述したように、加振クリーニングブレードでクリーニングする場合、ある程度の振動変位量が必要であり、これを実現するためには共振周波数を使ったほうが良い。仮に、共振周波数を使うことができない場合、一定の駆動条件で加振することは可能であるが、非常に微小であり、駆動させるに必要な電圧も大きくなりやすいため、圧電素子への負荷となったり、駆動させるに必要な電源も容量の大きなものが余計に必要なため好ましくない。
【０１６５】
この感光体の摩擦係数によって、共振周波数を変化させる方法は、実際に画像形成装置で作像させるような場合であって、途中から共振周波数を変えることが装置の関係上、たとえばコストを抑えるために周波数を変化させることができない駆動回路を搭載する場合や、共振周波数の広がりが割合大きい場合（中心位置である周波数に対し、裾が大きくなるようなブレード）では、共振周波数近傍で圧電素子を駆動させれば、ある程度の振動変位量を確保でき、クリーニング性も良好になるため、初期の感光体表面と加振クリーニングブレードの組み合わせで決まる共振周波数を検出（測定）しておき、その共振周波数で圧電素子を駆動させる構成が好ましい。
【０１６６】
（２）像担持体回転トルク
図２に示す画像形成装置内に取り付けられるドラム状の像担持体の軸に回転トルクメータを取り付け、回転動作時にトルクを測定した。この測定の際に、像担持体に当接するのは加振手段を設けたクリーニングブレード２３のみとして回転トルクを測定した。なお、クリーニング性の評価は、前述したように、帯電工程、現像工程、転写工程の顕像化させるために必要な工程を組み込んだ。ブレードと像担持体との摩擦抵抗力に相当する測定手段（検出手段）としては、このトルクメータを画像形成装置に取り込むことが、直接的に摩擦抵抗力を診る、という点で最適である。
【０１６７】
ここでは、ドラム状のＯＰＣについて行ったが、ベルト状の感光体についても同じように測定が可能である。しかし、ブレードが当接し、トナーをクリーニングするためには、感光体との接触が必要であるため、できるだけブレードに近い位置にトルクメータを配置させることが好ましい。ベルト感光体の場合、クリーニングにはある程度のベルトとブレードとの圧力が必要であるため、ベルトを懸架させるローラ等が設けられている場合が多い。トルクメータの配置箇所は、このブレードに最も近接する懸架ローラの軸に取りつけることが好ましい。
【０１６８】
先の感光体摩擦係数の変化と同じように、感光体回転トルクを意図的に変化させたときであって、加振クリーニングブレード２０を動作させたときの振動解析とクリーニング性を評価した。これも、前述したと同様に、ホワイトノイズを圧電素子に入力しパソコン上での振動解析を行った。
【０１６９】
振動解析の結果は図示はしないがに示すように、先の結果と同じようにトルクの違いによって、２４ｋＨｚ付近（このときの正確な周波数を周波数ｅとすると、ここでの周波数ｅは前述した周波数ｂと同じ値となった。）に振動変位量が大きくなる共振周波数を持つことが分かった。しかし、トルクの違いにより、その変位が最大の周波数がやはり先と同じように１ｋＨｚ程度の幅（ｄ、ｅ、ｆ）で変化していることが分かった。
【０１７０】
この原因についての詳細は、先の感光体そのものの摩擦係数と同じ理由であると考えられる。すなわち、トルクが上がる、という現象をブレードニップと感光体表面とでの負荷が増加することによって、引き起こされると考えられる。その負荷は、クリーニングを行うニップ部が下流側に持っていかれることにより発生すると推測される。
【０１７１】
次に、各トルクの値に対して、先に得られた共振周波数を駆動周波数とし、波形として正弦波を入力した時の感光体上のクリーニング性を判定した結果と、周波数ｅで固定して、トルクの値だけを変化させたときの結果も合わせて表２に示している。
【０１７２】
【表２】

【０１７３】
この表２によれば、感光体回転のトルクが変化しても、そのときに発生する共振周波数で圧電素子を駆動させればクリーニング性は良好であるが、感光体回転のトルクが変化しても固定の周波数で駆動させた場合、クリーニング性が良好にはならないことが分かる。この原因としては、先に記載した理由と同じであると考えられる。
【０１７４】
このように、感光体が回転する時のトルクの変化によって、共振周波数を変化させる方法は、実際に画像形成装置で作像させるような場合であって、ある程度の耐久性を持たせる場合、すなわち感光体の表面がトナーの付着などによって変化しやすく、ブレードと感光体の摩擦力が変化しやすい場合に、トルク計の変化から共振周波数の変化を見積もって振動変位量をある程度確保できる最適な共振周波数に駆動条件を変化させ、クリーニングを最適にすることが可能となる。
【０１７５】
（クリーニング性と共振周波数）
これまでの加振クリーニングブレードを構成する圧電素子の駆動を制御する方法は、画像形成装置内に設けられた検知方法にレーザドップラ振動計を使用しているが、さらにコストを抑える必要がある場合にはクリーニング性そのものから共振周波数を見積もって最適なクリーニング状態にすることが可能である。その方法について説明する。
【０１７６】
これまで、表１及び表２に示すように加振クリーニングブレードと感光体との相関で決まる共振周波数以外ので圧電素子を駆動させても振動変位量が得られず、クリーニング性が不良になることが分かった。そこで、クリーニング性の評価結果から共振周波数の変化を読み取り、クリーニング性が悪く、出力される画像上に影響が出る傾向がある場合（たとえば、出力される画像上であって、非画像部にもトナーが付着する等）に圧電素子を駆動する周波数を共振周波数に近い値まで制御し、振動変位量を確保することでクリーニング性を向上することができる。
【０１７７】
この場合、図１０に示すように共振周波数に対して、前後のどちらかに周波数が移動しているか分からないが（ほぼ同じクリーニング性のレベルであった場合、共振周波数に対し、高い周波数、低い周波数ともに変化した可能性があるため）、数枚を出力し、クリーニング性がさらに悪化するようだったら、反対側に駆動周波数を制御すれば良い。このとき、操作する人間が実際に出力された画像を直接みて、クリーニング性の判定結果を画像形成装置へ反映させる方法が簡単である。
【０１７８】
また、画像形成装置がプリンタである場合には、プリンタにデータを転送するホスト側のプリンタドライバによって設定条件を変化させることもできる。
【０１７９】
さらに、自動化させたい場合には、多少のコストはかかるが、感光体の回転方向であって、加振クリーニングブレードの下流側に残トナーを検知するラインセンサを配置させ、感光体表面上のクリーニング性を検知し、この結果を信号として主制御部に入力して、加振手段の駆動周波数を変化させることで、クリーニング性を向上あるいは維持することが可能となる。
【０１８０】
このように、自動化、あるいは人間の設定が必要な非自動化いずれもクリーニングの結果から圧電素子の駆動周波数を変化させ、クリーニングに最適な条件にすることが可能になる。
【０１８１】
このように、駆動手段は駆動周波数を変化可能とすることによって、共振周波数に対応した駆動周波数で加振手段を駆動することができるようになる。
【０１８２】
そして、駆動周波数をブレード部材と像担持体との摩擦抵抗力に基づいて設定することで、装置内では実際に測定しにくい共振周波数に相関する摩擦抵抗力を用いることができて、容易に共振周波数に対応する駆動周波数で駆動することができ、クリーニングに最適な条件に設定することができる。
【０１８３】
この場合、摩擦抵抗力に相関する像担持体表面の摩擦係数に基づいて駆動周波数が設定（自動的あるいは半自動的、若しくは手動で設定）されるようにすることで、摩擦抵抗力を簡易的に把握する（低耐久性の像担持体での簡易的な把握：膜剥がれが進行する像担持体について検知する）ことができるようようになり、大掛かりな測定装置を備えることなく、簡単な構成で、容易に共振周波数に対応する駆動周波数に設定、制御して駆動することができ、クリーニングに最適な条件に設定することができる。
【０１８４】
また、摩擦抵抗力に相関する像担持体の回転トルクに基づいて駆動周波数が設定されるようにすることで、摩擦抵抗力の経時的な変化に対する追従性の向上を図る（及び、耐久性の高い像担持体における摩擦抵抗力を検知する）ことができ、経時的に像担持体表面状態の変動の大きい画像形成装置、あるいは、像担持体の交換がなく高耐久性の像担持体を有する画像形成装置であっても、正確に回転トルクで回転負荷を把握し、その負荷変動に応じて、駆動する駆動周波数の設定制御が可能で、クリーニングに最適な条件に設定することができる。
【０１８５】
さらに、駆動周波数をクリーニング性の検出結果に基づいて設定されるようにすることで、画像形成装置内での加振手段によるクリーニングブレードの共振周波数変化を検知することができ、クリーニングに最適な条件に設定することが可能となる。なお、一般にクリーニング性はブレード通過後の感光体上のトナー量で評価される。
【０１８６】
次に、クリーニング装置１６の加振クリーニングブレード２０の他の例について図１１及び図１２を参照して説明する。
この実施形態では、振動部材２２に振動を与える加振手段３３として積層型圧電素子を用いている。積層型圧電素子は、それ自体の固有振動数が５０〜１００ｋＨｚと高く、また発生変位力が非常に大きいので、積層型圧電素子を用いることで、振動部材２２の板厚を厚くしても高い振動数まで応答が可能な構成が容易となる。
【０１８７】
ここでは、加振手段３３を構成する積層型圧電素子は、例えば一層あたり１００μｍの圧電層３３ａと内部電極３３ｂとを交互に積層し、内部電極３３ｂは交互に両端面に引き出して端面電極（外部電極）に接続したものであり、その積層方向の変位であるｄ３３方向変位を利用する構成としている。
【０１８８】
なお、積層型圧電素子を用いて複数層積層した積層方向に対して直角となる面方向の変位、即ちｄ３１方向変位を利用する構成とすることもでき、この場合変位量が大きくとれ、低電圧化を図れ、ドライバ（駆動回路）コストの低減を図れる。この構成を採用する場合、加振手段２３を構成する積層型圧電素子以外図９と同様の構成である。
【０１８９】
ここで、振動部材２２は弾性変形可能な薄板状であり、この振動部材２２と対向しする支持部３５ａを有する剛性の高いホルダである固定部材３５に振動部材２２の固定端を固定し、固定部材３５の支持部３５ａと振動部材２２との間に加振手段３３である積層型圧電素子が挟まれるように配置している。ブレード部材２１は加振手段３３からの振動が振動部材２２を介して伝わるように、振動部材２２の加振手段２３３とは反対面の先端領域に配置している。
【０１９０】
このように、加振手段を固定部と振動部材との間に設けた構成とすることで、効率的に振動部材に振動を伝えることができる。
【０１９１】
また、加振手段３３は、図１２に示すように、像担持体１の幅方向で複数個設けている。加振手段３３は、比較的幅が狭いブレード部材２１の場合、積層圧電素子の断面積の大きいものを使用すれば、１個とする構成も可能である。
【０１９２】
次に、本発明に係るクリーニング装置を含む本発明に係るプロセスカ−トリッジについて図１３を参照して説明する。なお、同図は同プロセスカートリッジの概略構成断面図である。
【０１９３】
このプロセスカートリッジ５０は、像担持体５１、帯電手段５２、現像手段５４、本発明に係るクリーニング装置５６等の構成要素のうち、複数のものをプロセスカ−トリッジとして一体に結合して構成し、このプロセスカ−トリッジを複写機やプリンタ等の画像形成装置本体に対して着脱可能に構成している。
【０１９４】
クリ−ニング装置５６を着脱自在であるプロセスカ−トリッジ内に具備させることにより、メンテナンス性の向上、他の装置との一体交換が容易に行うことができるようになる。
【０１９５】
次に、本発明に係るプロセスカートリッジを用いたカラー画像形成装置について図１４を参照して説明する。
この画像形成装置は、水平に延在する転写ベルト（像担持体）６１に沿って、各色の上述したプロセスカ−トリッジ５０を並置した形式のカラー画像形成装置である。
【０１９６】
プロセスカ−トリッジ５０は、イエロー、マゼンタ、シアン、ブラックの各色ごとに４つ配置されている。各プロセスカ−トリッジ５０で現像された像担持体６１上の現像トナーは水平に延在する転写電圧が印加された転写ベルト６１に順次転写される。
【０１９７】
このようにイエロー、マゼンタ、シアン、ブラックと画像の形成が行なわれ、転写ベルト６１上に多重に転写され、転写手段６２で転写材１８にまとめて転写される。そして、転写材１８上の多重トナー像は図示しない定着装置によって定着される。プロセスカ−トリッジ５０は、イエロー、マゼンタ、シアン、ブラックの順で説明したが、この順番に特定されるものではなく、どの順番で並置してもよい。
【０１９８】
通常、カラーの画像形成装置は複数の画像形成部を有するため装置が大きくなってしまう。また、クリーニングや帯電などの各ユニットが個別で故障したり、寿命による交換時期がきた場合は、装置が複雑でユニットの交換に非常に手間がかかっていた。
【０１９９】
そこで、本実施形態のように、像担持体、帯電手段、現像手段の構成要素をプロセスカ−トリッジ５０として一体に結合して構成することによって、ユーザーによる交換も可能な小型で高耐久のカラー画像形成装置を提供することができる。
【０２００】
【発明の効果】
以上説明したように、本発明に係るクリーニング装置によれば、クリーニングブレード部材を振動させるための加振手段を共振周波数を駆動周波数として駆動するようにしたので、振動量を確保することができてクリーニング性を維持することができる。
【０２０１】
本発明に係る画像形成装置によれば、本発明に係るクリーニング装置を備えているので、クリーニング不良がなく、高画質画像を形成することができる。
【０２０２】
本発明に係るプロセスカートリッジによれば、本発明に係るクリーニング装置を備えているので、クリーニング不良がなく、高画質画像を形成することが可能になる。
【０２０３】
本発明に係る画像形成装置によれば、本発明に係る複数のプロセスカートリッジを備えているので、クリーニング不良がなく、高画質カラー画像を形成することが可能になる。
【図面の簡単な説明】
【図１】本発明に係るクリーニング装置のクリーニングメカニズムを説明するための説明図
【図２】本発明に係るクリーニング装置を備えた本発明に係る画像形成装置の概略構成図
【図３】同画像形成装置のクリーニング装置の一例を示す加振クリーニングブレードの要部拡大説明図
【図４】図３の要部拡大説明図
【図５】同加振クリーニングブレードの正面説明図
【図６】同加振クリーニングブレードを先端側から見た説明図である。
【図７】同クリーニング装置の駆動制御系の一例を説明する説明図
【図８】トナーの円形度の説明に供する説明図
【図９】共振周波数の測定の説明に供する説明図
【図１０】周波数と変位量の関係の測定結果の一例を示す説明図
【図１１】本発明に係るクリーニング装置の加振クリーニングブレードの他の例の説明に供する説明図
【図１２】同加振クリーニングブレードの像担持体幅方向の説明図
【図１３】本発明に係るプロセスカートリッジの説明に供する説明図
【図１４】本発明に係るプロセスカートリッジを備えた本発明に係る画像形成装置の概略構成図
【図１５】従来のクリーニングブレードの説明に供する説明図
【図１６】同クリーニングブレードの像担持体が移動しているときの状態を示す要部拡大説明図
【図１７】同クリーニングブレードを用いた粉砕トナーのクリーニングメカニズムの説明に供する説明図
【図１８】同クリーニングブレードを用いた粉砕トナーのクリーニングメカニズムにおけるスティック・スリップ運動の説明に供する説明図
【図１９】同クリーニングブレードを用いた球形トナーのクリーニング不良の発生メカニズを説明する説明図
【図２０】同クリーニングブレードを用いた球形トナーのクリーニング不良の発生メカニズを説明する説明図
【符号の説明】
１…ブレード部材、１１…像担持体、２０…加振クリーニングブレード、２１…ブレード部材、２２…振動部材、２３…加振手段、２８…駆動回路、５０…プロセスカートリッジ。[0001]
[Industrial applications]
The present invention relates to a cleaning device, an image forming apparatus, and a process cartridge.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-188452
[Patent Document 2] JP-A-2000-267536
[Patent Document 3] JP-A-62-111489
[Patent Document 4] JP-A-6-51673
[Patent Document 5] JP-A-11-30938
[0003]
2. Description of the Related Art In an image forming apparatus using an electrophotographic method, such as a printer, a facsimile, and a copier, an electrostatic latent image formed by charging and exposing an image carrier surface is developed with a colored toner to form a toner image as a visible image. The toner image is formed and transferred to a transfer target such as transfer paper, or once transferred to an intermediate transfer member, and then transferred to a transfer target such as transfer paper, and fixed with a hot roll or the like to form an image. Has formed.
[0004]
Since untransferred toner generally remains on the surface of the image carrier after the transfer of the toner image, it is necessary to remove the residual toner by some cleaning means prior to the next image forming process. . In general, other foreign substances adhering to the surface of the image carrier are removed together with the residual toner by a cleaning unit.
[0005]
Various methods such as a method using a fur brush, a magnetic brush and the like, and a method using a cleaning blade made of an elastic material are used as cleaning means for removing the residual toner and the like of the transfer. Means for scraping off the toner by rubbing the image carrier with a cleaning blade is generally used because of its low cost and high performance stability. As an elastic body used as a material of the cleaning blade, polyurethane rubber is often used because of its excellent wear resistance.
[0006]
On the other hand, in recent years, in order to improve the image quality of a full-color image forming apparatus, toner particles have been reduced in particle size and made spherical. By reducing the diameter, the reproducibility of the dots of the toner image formed on the surface of the image carrier can be improved, and by making the particles spherical, the developability and transferability can be improved.
[0007]
As described above, instead of the conventional pulverization method, a method of producing a polymerized toner accompanied by a polymerization reaction, which is a chemical reaction, has been performed as a method of forming a toner into a spherical shape for improving image quality. As a method for producing this polymerized toner, even if it is in the same category of the polymerization reaction, there are some differences in the production method, but there is no need for a pulverizing and classification step as in the case of a pulverized toner, or this step can be greatly reduced. This is advantageous.
[0008]
[Problems to be solved by the invention]
However, in the case of using the above-described spherical toner having a small particle diameter (hereinafter, these may be referred to as “spherical toner”), a problem that good cleaning performance cannot be obtained, particularly in a blade cleaning system. May occur.
[0009]
It has been clarified that this cleaning performance defect and cleaning defect occur even when the conventional pulverized toner is reduced in particle size and sphere by mechanical treatment (re-pulverization) or heat treatment. Regardless of the manufacturing method, when the toner has a small particle size and a spherical shape, good cleaning performance cannot be obtained by blade cleaning.
[0010]
The toner having such a cleaning defect becomes an image quality defect at the time of forming the next output image. In particular, when the charging device is a roller-type contact type charger, the toner cannot be removed by the cleaning blade (not cleaned). ) The effect is large because toner may accumulate on the roll-shaped charger and cause charging failure.
[0011]
In particular, in the case of a toner in which the circularity of the toner (the details of the circularity will be described later) is close to 1, that is, in the case of a toner having a spherical shape (true sphere), the cleaning property is significantly deteriorated. Even a toner having a circularity of 0.95 or less has a shape distribution, and therefore has a substantially spherical toner, and the cleaning property tends to deteriorate over time.
[0012]
In addition, the cleaning property tends to deteriorate as the particle size of the toner used for development decreases. The image forming apparatus is used in a temperature range of about 10 ° C. to 30 ° C., and especially at a low temperature, the deterioration of the cleaning property becomes remarkable.
[0013]
In the cleaning method using a cleaning blade, since the toner is scraped off by rubbing the image carrier with the rubber blade as described above, the edge tip of the rubber blade is caused by frictional resistance between the image carrier and the rubber blade. It is deformed, forming a small wedge-shaped space between the two. In this space, the smaller the diameter of the toner is, the more easily the toner enters the edge tip, and the toner that has entered the edge tip is hard to be replaced, and forms a non-flow area.
[0014]
Further, since spherical toner is more likely to be packed closest than irregular toner, it is likely to be compacted in a minute space near the contact point between the edge of the cleaning blade and the image carrier. In a state where the frictional resistance between the toner in the non-flow area and the image carrier is relatively small and the toner is slipping on the image carrier, no cleaning failure occurs, but the external additive due to the rubbing with the image carrier. When the frictional force between the toner and the image carrier increases due to separation of the toner, the spherical toner starts to roll between the cleaning blade and the image carrier and slips through because the rolling friction is smaller than that of the conventional crushed irregular-shaped toner. Conceivable.
[0015]
Therefore,
In Japanese Patent Application Laid-Open Publication No. H10-157, cleaning is performed by scraping off residual toner on the surface of a photoreceptor after transfer in order to efficiently remove residual toner on an image carrier of an image forming apparatus using a spherical toner manufactured by a polymerization method. There is disclosed a cleaning device that includes a blade and a cleaning brush that is disposed upstream of the cleaning blade in the moving direction of the photoconductor and that crushes residual toner to generate fine toner on the photoconductor.
[0016]
Also,
In Japanese Patent Application Laid-Open No. H11-163, in order to improve the cleaning performance of an image carrier cleaning blade of an image forming apparatus for spherical toner, a surface carrying a toner image formed by spherical toner passes through a transfer area and a cleaning area. A rotatable toner image carrier, a transfer device for transferring a toner image on the surface of the toner image carrier passing through the transfer area to a transfer material, and a frictional contact with the toner image carrier surface passing through the cleaning area. A cleaning blade made of an elastic member having a blade edge for removing residual toner on the surface of the toner image carrier; and a powder lubricant applied to the blade edge and an irregular toner having an average particle diameter smaller than the spherical toner. There is disclosed an image forming apparatus including a toner image carrier cleaner having a mixed powder material.
[0017]
On the other hand, as a cleaning device for an image forming apparatus,
As disclosed in Japanese Patent Application Laid-Open No. H11-163, the cleaning blade is forcibly applied to drop toner or foreign matter that is to adhere to the cleaning blade and to prevent squeal due to solid contact between the cleaning blade and the photoconductor. Some are made to vibrate dynamically.
[0018]
Also,
As disclosed in Japanese Patent Application Laid-Open No. H10-157, the photosensitive member is brought into contact with the photosensitive member and shaken.
There is one provided with a vibration means capable of adding motion. further,
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-157, the vibration blade is provided with vibration means for applying vibration to a fixed end (non-cleaning portion) of a cleaning blade to float particles on the surface and remove the particles from the surface. There is also.
[0019]
[Problems to be solved by the invention]
However,
The cleaning device described in Patent Document 1 has a cleaning brush that crushes residual toner to generate fine toner on a photoreceptor, thus not only increasing the size of the device, but also cleaning the resin toner. It is very difficult to pulverize, and even if it can be pulverized, damage to the surface of the image carrier occurs, and the image quality deteriorates.
[0020]
Also,
In the cleaning device described in Patent Document 2, since a mixed powder material with an irregular toner having an average particle diameter smaller than that of the spherical toner is used, the image quality is improved by using the spherical toner. Is reduced, and as a result, image quality is reduced.
[0021]
further,
[Patent Document 3],
[Patent Document 4] and
In the cleaning device described in Japanese Patent Application Laid-Open No. H11-163, only a vibration for dropping toner or the like adhering to a cleaning blade or a vibration for floating toner from the surface of an image carrier is applied, and a spherical toner is used. Since the vibration corresponding to the mechanism of the occurrence of the cleaning failure is not given, the cleaning failure occurs for the spherical toner.
[0022]
Therefore, the present inventors first studied the mechanism of the cause of the occurrence of cleaning failure in the counter-type cleaning blade when spherical toner was used, and clarified the mechanism.
[0023]
That is, as shown in FIG. 15, in a typical cleaning apparatus using a counter-type cleaning blade, the tip of the cleaning blade 101 held by the metal holder 100 is moved relative to the image carrier 111. An abutment surface 101c of the cleaning blade 101 and the surface of the image carrier 111 are brought into contact with each other so as to form a counter with respect to the rotation direction A, and the tip (free end) of the cleaning blade 101 is pressed by a pressing amount d. By pressing against the image carrier 111, the residual toner on the image carrier 111 is cleaned.
[0024]
Here, the conventional cleaning blade 101 is usually a rubber elastic member mainly composed of polyurethane rubber, and has a JIS hardness of 65 to 70 °, a thickness of about 1.5 to 2.0 mm, and a free length of the blade from the metal holder 100. Generally, the protrusion amount is 8 to 15 mm, and the contact angle θ is 20 to 30 °.
[0025]
When the image carrier 111 rotates in a state where the image carrier 111 and the cleaning blade 101 are in contact with each other, as shown in FIG. 16, the cleaning blade 101 is an elastic member. By moving in the direction A, the edge 101b of the cut surface 101a of the blade 101 is pulled in the direction A by the frictional force with the image carrier 111, and the cut surface 101a (tip surface) of the blade 101 is deformed and turned up. State. By turning up the cut surface 101a, a wedge-shaped nip portion N is formed between the cut surface 101a at the tip of the blade 101 and the image carrier 111.
[0026]
In this case, when the toner to be used is the pulverized toner, as shown in FIG. 17, the pulverized toner Ta has a distorted shape, and thus the wedge-shaped nip formed by the cleaning blade 101 and the image carrier 111 is used. As a result, the edge of the toner Ta is caught. At this time, a repelling force acts to return the deformed portion of the tip end surface of the blade 101 to the original state, and a so-called stick-slip motion occurs.
[0027]
This stick-slip motion will be described with reference to FIG. When the blade nip becomes sticky (fixed) on the surface of the moving image carrier, the blade nip is forcibly stretched in the rotation direction of the image carrier 111 as shown by a broken line in FIG. When the blade nip is extended to a certain position, the repulsive force of the blade increases, and when the static friction force and the repulsive force are balanced, the blade nip slides on the surface of the image carrier. In a state in which slippage occurs between the blade nip and the image carrier, the blade nip returns to the original direction (the direction shown by the solid line) while sliding on the surface of the image carrier because the dynamic friction coefficient is smaller than the static friction coefficient. Due to the returning force of the repetitive motion of the stick-slip (the range is indicated by SP), the toner Ta staying in the wedge-shaped nip portion is returned in the direction opposite to the traveling direction of the image carrier 111. It is cleaned by receiving force.
[0028]
In contrast, a case where spherical toner is used as the toner will be described with reference to FIG. This figure shows the behavior when the spherical toner Tb enters the wedge-shaped nip formed by the cleaning blade 101 and the image carrier 111.
[0029]
When the spherical toner Tb is used, since the toner does not have a distorted portion unlike the pulverized toner Ta, the toner does not catch on the tip of the blade 101, so that the toner enters the wedge-shaped nip portion, and the cleaning blade 101 and the image carrier 111. The spherical toner Tb sandwiched between the rollers receives a moment of rotation using the contact portion as a drive source due to frictional force with the image carrier 111. Therefore, the spherical toner Tb moves in the same direction as the rotation direction of the image carrier 111 while rotating in the direction opposite to the traveling direction of the image carrier 111, and passes through between the blade 101 and the image carrier 111. Cleaning failure occurs.
[0030]
At this time, once the spherical toner Tb slips through, the spherical toner Tb functions as a lubricant between the cleaning blade 101 and the image carrier 111 as shown in FIG. It functions to reduce the frictional force of the carrier 111 and release the curl of the tip (cut) surface of the blade 101 (return the blade 101 to its initial shape). Therefore, the above-described stick-slip motion, which is a basic function of cleaning by the blade 101, does not occur, and a phenomenon that toner cleaning failure occurs continuously occurs.
[0031]
Although the mechanism of the occurrence of defective cleaning of the spherical toner has been described above, the small-diameter toner is more likely to enter the wedge-shaped nip portion shown in FIG. It has been confirmed that the smaller the diameter of the toner is, the less the toner is caught at the edge portion, so that the toner easily passes through.
[0032]
The present invention has been made based on the above problems and knowledge, and provides a cleaning device having improved cleaning properties, an image forming apparatus and a process cartridge including the cleaning device, and an image forming apparatus including the process cartridge. The purpose is to do.
[0033]
[Means for Solving the Problems]
In order to solve the above problem, a cleaning device according to the present invention includes a vibration member that is long in the width direction to which one or a plurality of vibration units are attached, and a vibration member that is long in the width direction attached to at least a distal end region of the vibration member. A blade member and driving means for driving the vibrating means at the resonance frequency are provided, and the vibration member applies vibration to the blade member and presses the blade member against the image carrier.
[0034]
Here, it is preferable that the driving means can change the driving frequency. In this case, the driving frequency is preferably set based on the frictional resistance between the blade member and the image carrier. In this case, the drive frequency is set based on the friction coefficient of the surface of the image carrier, or set based on the rotational torque of the image carrier, or set based on the detection result of the cleaning property. Is preferred.
[0035]
Preferably, the vibrating means is a piezoelectric element. Further, it is preferable that the toner is a polymerized toner produced by a polymerization method.
[0036]
The process cartridge according to the present invention includes an image carrier, a charging unit, a developing unit, and a transfer unit, and a cleaning unit, and is detachable from an image forming apparatus main body. It was configured as a cleaning device.
[0037]
An image forming apparatus according to the present invention is configured to include the cleaning device according to the present invention or the process cartridge according to the present invention for cleaning toner remaining on the surface of an image carrier.
[0038]
An image forming apparatus according to the present invention is configured to include a plurality of process cartridges according to the present invention.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, a cleaning mechanism by the cleaning device according to the present invention will be described with reference to FIG.
The cleaning device according to the present invention has a configuration in which vibration is efficiently applied to a tip region of a blade member (hereinafter, also referred to as a “cleaning blade”) 1. Then, the vibration of the blade member 1 is transmitted to the toner T between the tip of the blade member 1 and the image carrier 11, and the vibration of the tip region of the blade member 1 is transmitted to the image carrier 1. Vibration is also transmitted from the image carrier 1 to the toner T.
[0040]
These vibrating operations are performed by vibrating the nip portion of the blade member 1 so that the nip portion has a shape and movement different from those of a conventional cleaning device using vibration, so that spherical toner and small-diameter toner enter the blade nip portion. Thus, it is possible to eliminate defective cleaning of the spherical toner and the small-diameter toner.
[0041]
That is, FIG. 1 illustrates a state in which the blade member 1 is in a vibrating state, the vibration is transmitted to the spherical toner T, and the toner T is actively vibrating (indicated by a white arrow in the figure). FIG. This illustrates the result of observation with a high-speed video camera through a high-power microscope. At this time, as shown in the figure, the blade member 1 is not turned up in the cut surface, and the edge 1b of the cut surface 1a may be in a state of maintaining the initial shape with respect to the surface of the image carrier 11. I understand. Incidentally, reference numeral 1c in the figure denotes an abdominal surface of the blade member 1 (a surface facing the surface of the image carrier 11).
[0042]
Then, at this time, it is found that the spherical toner T in the vicinity of the tip cut surface 1a of the blade member 1 and the image carrier 11 oscillates over a range of several toners (range B in the drawing). did.
[0043]
In such a state, the vibrating toner group (toner of the portion B) near the nip portion acts like a barrier (oscillating toner wall), and the toner T (the portion C in FIG. ) Is prevented, and cleaning failure does not occur at all even for a spherical toner that is close to a true sphere.
[0044]
At this time, the frictional force between the blade member 1 and the image carrier 2 is reduced by vibrating the blade member 1 and transmitting the vibration from the blade member 1 to the image carrier 11. It has been found that there is a condition that eliminates the phenomenon in which the cut surface 1a of the blade member 1 that has occurred is eliminated. The term "turning of the cut surface" used here means that a molded elastic member is usually cut in the thickness direction and its edge is finished with a sharp shape without burrs, chips, etc. This means that the surface is deformed as the image carrier moves and comes into contact with the surface of the image carrier (the state shown in FIG. 23 described above).
[0045]
Eliminating the occurrence of the turning of the cut surface of the blade member 1 reduces the stress from the blade member 1 to the image carrier 11, and as a result, the durability of the blade member 1 and the image carrier 11 is significantly improved. It was also found that a very great effect of improvement was obtained.
[0046]
As described above, the cleaning operation is performed by vibrating the blade member to generate a contact portion between the surface of the blade member and the image carrier. As a “vibration cleaning blade”). This portion is called a nip portion. The inventor's earnest research has shown that the cleaning blade (blade member) is vibrated by the vibrating means, and the amount of vibration displacement has a correlation with the cleaning performance. The correlation means that the greater the vibration displacement of the cleaning blade, the better the cleaning performance.
[0047]
However, as long as the vibration means vibrates under any vibration conditions, the cleaning property is not improved. Depending on the conditions, a phenomenon in which the effect of the vibration does not appear at all has also been found by the inventors' earnest research.
[0048]
By the way, when the cleaning blade and the image carrier are assembled, it is known that the cleaning blade and the image carrier have natural vibrations at frequencies different from the natural frequencies of the respective members. This is not limited to the blade and the image carrier, and is an event that always occurs between the two bodies. The natural frequency at this time is called a “resonance frequency”.
[0049]
As described above, in the cleaning property, it has been described that the larger the vibration displacement amount by the vibrating means, the better the cleaning property. In order to secure the vibration displacement amount with as little energy as possible, it has been found that the vibration means should be driven at the resonance frequency at the time of the cleaning operation, that is, when the cleaning blade and the image carrier are assembled. Therefore, in one example of the present invention, by using a piezoelectric element, which is easy to drive and control, as a vibration means, and driving at a resonance frequency, a larger vibration displacement can be obtained with a small driving voltage. I have. .
[0050]
In the vibrating cleaning blade, a resonance frequency (a natural frequency determined by the blade and the image carrier) that changes during the cleaning operation or is determined to some extent when the blade and the image carrier are assembled is applied. The cleaning property can be maintained by using the driving frequency of the vibration means and securing the vibration displacement amount.
[0051]
Here, it is preferable that the driving frequency for driving the piezoelectric element is outside the audible range. The reason for this is that if the driving frequency is in the audible range, unpleasant sounds for humans will enter the cleaning operation, which is not preferable. It is preferable to drive as much as possible outside the audible range, specifically at a frequency other than 20 Hz to 17 kHz. However, if a configuration capable of soundproofing the entire vibrating cleaning blade can be mounted on the image forming apparatus, The drive frequency may be in the audible range.
[0052]
Thus, an image forming apparatus according to the present invention including the cleaning device according to the present invention will be described below with reference to FIG. FIG. 1 is a schematic configuration diagram of the image forming apparatus.
[0053]
This image forming apparatus includes an image carrier 11 that rotates in the direction of arrow A, and a charging unit 12, an exposure unit 13, a developing unit 14, a transfer unit 15, a cleaning device 16, and a charge removing unit 17 are arranged around the image carrier 11. . Further, a fixing device (not shown) for fixing the toner image on the transfer material 18 transferred from the image carrier 11 is provided.
[0054]
Here, the charging unit 12 is disposed on the surface of the image carrier 11 at a predetermined distance in contact with or not in contact with the image carrier 11. By applying a bias to the charging unit 12, the image carrier 11 has a predetermined polarity, It is charged to a predetermined potential.
[0055]
The exposing unit 13 uses an LD or LED as a light emitting element, and irradiates the image carrier 11 with light based on image data to form an electrostatic latent image.
[0056]
The developing means 14 includes a magnet roller fixed inside and a rotatable developer carrier 14A, and holds the developer on the developer carrier 14A. In this image forming apparatus, two-component magnetic brush development is performed using a two-component developer composed of a toner and a carrier as a developer. As another developing method, a one-component developing method using no carrier may be used.
[0057]
A voltage is applied to the developer carrier 14A from a developing bias power supply. Due to the potential difference between the developing bias and the potential of the electrostatic latent image formed on the surface of the image carrier 11, the charged toner is attached to the electrostatic latent image in the developing area to perform development.
[0058]
The transfer means 15 comes into contact with the surface of the image carrier 11 with a predetermined pressing force at the time of transfer, and a voltage is applied, so that the surface of the image carrier 11 is transferred at a transfer nip portion between the image carrier 11 and the transfer means 15. Is transferred to the transfer material 18. In this image forming apparatus, transfer is performed using a transfer roller, but transfer means such as a corotron or a transfer belt may be used.
[0059]
The cleaning device 16 is a cleaning device according to the present invention, and includes a blade member 21, a vibrating member 22, a vibrating means 23, and a portion composed of these members is referred to as a "vibrating cleaning blade 20". By driving the vibrating means 23 to vibrate the vibration member 22 and apply a required vibration to the blade member (hereinafter referred to as “blade”) 21, the residual toner on the surface of the image carrier 11 is removed.
[0060]
The toner cleaned from the image carrier 11 by the cleaning device 16 is stored in a waste toner bottle (not shown) as waste toner by a toner transport member, collected by a service person or the like, or transported to a developing device or the like as recycled toner. Used for development.
[0061]
The charge removing means 17 removes the residual charge of the image carrier 11 from which the residual toner has been removed by the cleaning device 16, and uses an optical charge removing device using an LED or the like.
[0062]
Next, details of an example of the configuration of the cleaning device 16 will be described with reference to FIGS. 3 is an enlarged view of a main part of the vibrating cleaning blade of the cleaning device, FIG. 4 is an enlarged explanatory view of a main part of FIG. 3, FIG. 5 is a front view of the vibrating cleaning blade, and FIG. FIG. 4 is an explanatory view of the vibration cleaning blade viewed from a tip end side.
[0063]
As described above, the vibrating cleaning blade 20 of the cleaning device 16 includes a blade 21 having substantially the same width as the axial direction of the image carrier 11, and the same image carrier 11 having the blade 21 attached to the distal end region. A vibration member 22 having substantially the same width as the axial width of the vibration member 22 and vibration means 23 attached to the vibration member 22.
[0064]
The blade 21 is arranged in contact with the rotating direction of the image carrier 11 in a leading (counter) direction.
[0065]
The blade 21 is an elastic body made of, for example, polyurethane rubber and has a thickness in the range of 50 to 2000 μm, preferably in the range of 100 to 500 μm. If the thickness is too small, it is difficult to secure the pressing amount of the blade 21 against the image carrier 11 due to the undulation of the surface of the image carrier 11 and the blade 21 itself. If the thickness is too large, the vibration from the vibration member 22 will be absorbed, and the vibration to the tip of the blade 21 will not be sufficiently transmitted, and the cleaning property of the toner will decrease. When the thickness of the blade 21 is large, the vibration transmission efficiency can be increased by using a hard member having a JISA hardness in the range of 85 to 100 ° as the material of the blade 21.
[0066]
Here, depending on the method of manufacturing the thin urethane blade, a structure in which one or more members are interposed between the blade 21 and the vibration member 22 may be employed. For example, when molding a thin urethane blade, it is integrally joined to an existing resin film such as PET having a higher hardness than urethane. As a result, the nip portion of the flade 21 needs a sharp edge, but the handling of the cutting operation for that purpose is improved. In this case, after integrally cutting PET and urethane, the PFT side is joined to the vibration member 22 and attached.
[0067]
The vibrating member 22 is formed of a material that can vibrate and has higher rigidity than the elastic blade 21, such as a metal member such as a soft steel plate or a SUS plate, or a resin molded member mixed with carbon or glass fiber. . The vibrating member 22 has one end fixed to the fixing portion 24 and the other end as a free end 23a, and the blade 21 is attached to the free end. The fixing portion 24 is fixed to a housing 25 of the cleaning device as shown in FIG.
[0068]
The vibrating member 22 also functions as a holder for the blade 21 and is a member that determines a pressing force of the blade 21 against the image carrier 11 and a contact angle. That is, in the conventional blade, the pressing force of the blade nip against the image carrier is given by the restoring force of the elastic blade itself. On the other hand, in the present invention, the blade 21 has a thin member configuration in order to increase the propagation efficiency of vibration, and the pressing force of the blade alone cannot be secured. It is configured to apply a pressing force to the image carrier 11.
[0069]
As a result, the vibration propagation efficiency can be increased while using a thin elastic blade member, and the nip corresponding to the warpage of the blade member and the undulation of the surface of the image carrier can be formed stably, and the reliable cleaning performance can be obtained. Can be
[0070]
The vibration means 23 applies vibration to the vibration member 22, and here uses a piezoelectric element as an electromechanical conversion element, particularly a plate-like (single-plate) piezoelectric element. By using a plate-shaped piezoelectric element as the vibration means 23, a vibration means capable of easily obtaining a displacement amount at low cost can be configured.
[0071]
As shown in FIGS. 5 and 6, the vibrating means 23 has a configuration in which the blade 21 and the vibration member 22 are long in the axial direction (width direction) of the image carrier 11 and a plurality of vibration members 22 are arranged on the vibration member 22. I have. The number of the vibrating means 23 may be one, but by arranging a plurality of them at intervals, it is easy to obtain the uniformity of the vibration of the vibration member 22 in the width direction. Although it is conceivable to provide one long piezoelectric element, in the case of a plate-shaped piezoelectric element, it is preferable to arrange a plurality of piezoelectric elements at an interval in order to use bending deformation due to expansion and contraction in the plate surface direction. .
[0072]
The vibrating means 23 is provided near the tip of the vibrating member 22 on the image carrier 1 side, that is, on the surface of the free end 22b opposite to the blade and the mounting surface. Depending on the configuration of the vibration member 22, the mounting position is not particularly limited as long as the vibration means 23 can vibrate the vibration member 22 between the fixed end of the vibration member 23 and the tip (free end) of the blade 21. Absent.
[0073]
As shown in FIG. 4, the single-plate piezoelectric element constituting the vibration means 23 is formed by printing and firing on both surfaces of a piezoelectric layer 23a of lead zirconate titanate or the like, that is, on the bonding surface with the vibration member 22 and the opposite surface. Electrodes 23b and 23c made of Ag or the like. By applying a voltage of 100 to 300 V to a piezoelectric element (piezoelectric layer 23a) having a thickness of 0.3 to 0.5 mm, which is polarized by using the electrodes 23b and 23c, the contraction deformation in the plate surface direction is reduced. As a result, deformation vibration that causes the vibration member 22 to bend can be given. This bending vibration has a high deformation efficiency when the rigidity of the piezoelectric element (vibration means 23) and the vibration member 22 are substantially the same. For example, the metal vibration member 22 having a thickness of 0.2 to 0.4 mm or the thickness of 0 is used. It is preferable to use a resin vibration member having a thickness of 0.3 to 1.0 mm.
[0074]
As shown in FIG. 7, in the cleaning device 16, as shown in FIG. 7, a driving signal (driving waveform) is commonly applied to the piezoelectric elements constituting the plurality of vibrating means 23 of the vibrating blade 20. There is provided a drive circuit 28 which is a drive unit according to the present invention for applying Pv.
[0075]
As described above, when a plurality of vibrating units are provided in the width direction of the blade member, by driving with a common drive circuit, the uniformity of vibration in the width direction of the blade member can be improved.
[0076]
The driving circuit 28 is controlled by the main control unit 29 of the image forming apparatus, and supplies a driving signal Pv having a required driving frequency, here a resonance frequency, to the vibration means 23 at a predetermined timing. Further, in this embodiment, one vibration cleaning blade 20 is used to clean the entire width of the image carrier 11 in the width direction. However, a plurality of vibration cleaning blades 20 are provided to cover the entire width in the width direction. (In this case, the blade 21 and the vibration member 22 have a length obtained by dividing the width of the image carrier 11 in the axial direction into a plurality of parts.) In this case as well, each of the plurality of vibrating cleaning blades 20 is provided. It is preferable that the vibration means is driven by a common driving circuit.
[0077]
Here, in this embodiment, a metallic member (conductive member) is used as the vibration member 22, and the electrodes 23 c of the piezoelectric elements constituting the plurality of vibration means 23 are directly contacted with the vibration member 22 to electrically connect the vibration members 22. By connecting, the electrodes 23c of the plurality of vibrating means 23 are commonly connected via the vibrating member 22. This makes it possible to apply the drive signal with a simple circuit configuration. The direct contact can be easily obtained by finishing the bonding surface side of the electrode 23c to a rough surface and bonding the electrode 23c to the vibration member 22 with a thin adhesive layer. Alternatively, the direct contact may be performed using a conductive adhesive. Good.
[0078]
In the cleaning device 16 configured as described above, the driving circuit 28 supplies the driving signal Pv having the resonance frequency determined by the correlation between the vibration cleaning blade 20 and the image carrier 11 to the plurality of vibration means 23. The vibrating member 22 vibrates by giving bending deformation to the piezoelectric elements constituting the plurality of vibrating means 23, and the blade 21 vibrates at the resonance frequency by the vibration of the vibrating member 22.
[0079]
In this way, by driving the vibration means at the resonance frequency to apply the vibration to the blade member and the pressing force of the blade member against the image carrier by the vibration member, the vibration displacement amount can be secured, High cleaning performance of the vibrating cleaning blade for toner remaining on the surface of the carrier can be ensured. In this case, the drive at the resonance frequency can be easily performed by using the piezoelectric element as the vibration means.
[0080]
Therefore, embodiments of the present invention will be described more specifically.
(How to drive the vibrating cleaning blade)
A driving waveform (driving signal) for causing a constant vibration of a set voltage value to be applied to the piezoelectric element serving as the vibration means 23 from a driving power supply. The drive power supply was experimentally constituted by a function generator for generating a pulse signal, and was applied to the piezoelectric element through a power supply for amplifying a signal generated from the function generator. Then, in order to observe the voltage actually applied to the piezoelectric element, the amplified voltage was branched and monitored by an oscilloscope.
[0081]
As described above, when a plurality of piezoelectric elements are arranged and operated, or when a plurality of color image carriers and cleaning blades need to be arranged as in a tandem machine, a plurality of function generators and power However, the same power supply may be divided into a plurality of power supplies, and each of them may be applied to the piezoelectric element. However, if the number of branches is large, a power supply having a sufficient output is required.
[0082]
In the image forming apparatus of the above-described embodiment and a process cartridge described later, a power supply in a smaller space is preferable. Therefore, the vibration means 23 is driven using a driver (drive circuit 28) in which a function generator and a power supply are integrated. . At this time, the main control unit 29, which controls the entire image forming apparatus and the process cartridge, changes the driving condition of the driver according to the situation, or synchronizes the driving condition with the operation sequence at the time of image formation or non-image formation. The driving of the vibration means 23 can be controlled.
[0083]
Next, the toner as the visualized particles used in the examples of the present invention will be described. (Example of Toner)
In this embodiment, a polymer toner having a high sphericity and produced by a solution suspension method was used in order to improve the image quality. The characteristics are as follows.
Circularity 0.980
Weight average particle size 5.41 μm
Carrier Silicon coated carrier with a weight average particle size of 50 μm
(Magnetite core material)
[0084]
Here, the circularity of the toner will be described. In order to form a high-quality image in an image forming apparatus using a spherical toner, it is important that the toner has a specific shape, the average circularity is less than 0.95, and the irregular shape is too far from the spherical shape. With the shape, a high quality image without transferability and dust cannot be obtained. Therefore, the circularity of the spherical toner is preferably 0.95 or more.
[0085]
As a method of measuring the shape, a method of an optical detection zone in which a suspension containing particles is passed through an imaging unit detection zone on a flat plate, and a particle image is optically detected and analyzed by a CCD camera is appropriate. is there. A toner having an average circularity of 0.95 or more, which is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of an actual particle, has a reproducible high-definition image with an appropriate density. It has been found to be effective in forming. FIG. 8 shows the definition of the circularity.
[0086]
More preferably, the average circularity of the toner is 0.960 to 0.998. This value can be measured as an average circularity by a flow type particle image analyzer FPIA-2000 (trade name, manufactured by Toa Medical Electronics Co., Ltd.). As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of water from which impurity solids have been removed in advance in a container. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the concentration of the dispersion is set to 3000 to 10,000 / μl, and the shape and distribution of the toner are measured by the above apparatus. .
[0087]
Further, the toner particle size can be measured as follows. The average particle size and particle size distribution of the toner were analyzed using a Coulter Multisizer III (manufactured by Coulter, trade name), connected to a personal computer (manufactured by IBM), and using dedicated analysis software (manufactured by Coulter). The Kd value was set using 10 μm standard particles, and the aperture current was set by automatic setting. As the electrolyte, a 1% NaCl aqueous solution is prepared using primary sodium chloride. In addition, ISOTON-II (trade name, manufactured by Coulter Scientific Japan) can be used.
[0088]
As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the aqueous electrolytic solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and 50,000 counts of toner of 2 μm or more were measured using a 100 μm aperture tube to obtain a weight average particle diameter.
[0089]
Next, a method for producing the polymerized and spherical toner will be described.
Examples of the method for producing the toner having a circularity of 0.960 to 0.998 include wet granulation such as suspension polymerization, emulsion aggregation, dispersion polymerization, interfacial polymerization, dissolution suspension, and phase inversion emulsification. Manufacturing method. In the case of a toner obtained by pulverizing and classifying a melt-kneaded product, a toner having a high circularity can be produced by heat treatment of the toner, but this is not preferable in terms of energy efficiency.
[0090]
Among the above-mentioned wet granulation methods, the suspension polymerization method and the dispersion polymerization method are superior in that a toner having a high circularity is stably obtained, a sharp particle size distribution is obtained, and the charge of the toner is controlled. ing. Further, the dissolution suspension method is excellent in that a polyester resin which is advantageous in terms of low-temperature fixability of the toner can be used. Hereinafter, the suspension polymerization method, the dispersion polymerization method, and the dissolution suspension method will be described in detail.
[0091]
(Suspension polymerization method)
For a specific monomer described below, a dispersion stabilizer, and a coloring agent, and further, if necessary, a crosslinking agent, a charge control agent, and a release agent are uniformly dispersed by a ball mill or the like, and then a polymerization initiator is added thereto. In addition, a monomer phase was obtained, and the aqueous dispersion medium phase prepared in advance by stirring with the monomer phase was placed in a stirring tank, stirred by a homogenizer, etc., and the resulting suspension was heated after replacement with nitrogen to carry out a polymerization reaction. Is completed to obtain colored resin particles, which are washed and dried to obtain toner particles having a high circularity.
[0092]
The polymerizable monomer used for suspension polymerization is a monomer having a vinyl group, and specific examples thereof include the following monomers. That is, styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, butyl styrene, styrene such as octyl styrene, and derivatives thereof, among which styrene monomers are most preferred .
[0093]
Other vinyl monomers include ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride, vinyl acetate, and vinyl propionate. , Vinyl esters such as vinyl benzoate and vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid-2 -Ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, n-methacrylic acid Acrylic acid or methacrylic acid such as octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, etc., α-methylene aliphatic monocarboxylic esters, acrylonitrile, methacrylonitrile, acrylamide Derivatives, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone N-vinyl compounds, vinyl naphthalene, and the like, and these monomers can be used alone or in combination.
[0094]
In the suspension polymerization method, in order to form a crosslinked polymer in the monomer composition, the following crosslinker may be used to carry out suspension polymerization. As the crosslinking agent, divinylbenzene, divinylnaphthalene, polyethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol diacrylate, Dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate , Trimethylol methane tetraacrylate, dibromoneopentyl glycol dimethacrylate, diallyl phthalate and the like.
[0095]
If the amount of the cross-linking agent is too large, the toner is less likely to be melted by heat, and the heat fixing property and the heat pressure fixing property are inferior. If the amount of the cross-linking agent is too small, the properties required for the toner, such as blocking resistance and durability, are reduced. A cold offset occurs in which the toner adheres and is transferred to the next paper. Therefore, the amount of the crosslinking agent used is 0.001 to 15 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer.
[0096]
The following can be used as the dispersion stabilizer in the suspension polymerization method. That is, polyvinyl alcohol, starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, water-soluble polymers such as sodium polyacrylate, sodium polymethacrylate, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay Diatomaceous earth, metal oxide powder and the like are used. These are preferably used in the range of 0.1 to 10% by weight based on water.
[0097]
In the suspension polymerization method, the polymerization initiator may be added to the dispersion liquid containing the monomer composition after granulation, but the point of imparting the polymerization initiator uniformly to the individual monomer composition particles. Therefore, it is preferable to include the monomer composition in the monomer composition before granulation. Examples of such a polymerization initiator include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, and 1,1'-azobis- (cyclohexane-1-yl). Azo-based or diazo-based polymerization initiators such as carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisbutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, and isopropyl peroxide And peroxide polymerization initiators such as 2,4-dichlorylbenzoyl peroxide and lauryl peroxide.
[0098]
In the suspension polymerization method, a magnetic toner containing a magnetic substance can be used. In order to obtain a magnetic toner, magnetic particles may be added to the monomer composition. Examples of the magnetic substance that can be used in the present invention include powders of ferromagnetic metals such as iron, cobalt, and nickel, and powders of alloys and compounds such as magnetite, hematite, and ferrite.
[0099]
As the magnetic particles, particles having a particle size of 0.05 to 5 μm, preferably 0.1 to 1 μm are used. In the case of producing a small particle size toner, magnetic particles having a particle size of 0.8 μm or less are used. Is preferred. The magnetic particles are preferably contained in an amount of 10 to 60 parts by weight based on 100 parts by weight of the monomer composition. Further, these magnetic particles may be treated with a surface treating agent such as a silane coupling agent or a titanium coupling agent, or an appropriate reactive resin. In this case, although it depends on the surface area of the magnetic particles or the density of the hydroxyl group present on the surface, usually, the surface treatment agent is used in an amount of 5 parts by weight or less, preferably 0.1 to 3 parts by weight per 100 parts by weight of the magnetic particles. Thus, sufficient dispersibility in the polymerizable monomer can be obtained, and the physical properties of the toner are not adversely affected.
[0100]
(Dispersion polymerization)
To the hydrophilic organic liquid, a polymer dispersant that dissolves in the hydrophilic organic liquid is added, and the polymer is dissolved in the hydrophilic liquid, but the resulting polymer is swollen by the hydrophilic liquid, or It is produced by adding one or more vinyl monomers that hardly dissolve and polymerizing. In addition, a reaction in which polymer particles having a particle size smaller than a target particle size and having a narrow particle size distribution are grown in the above-described system is also included. The monomer used for the growth reaction may be the same monomer as that used to produce the seed particles or another monomer, but the polymer must not be dissolved in the hydrophilic organic liquid.
[0101]
As the hydrophilic organic liquid as a diluent for the monomer used during the formation of the particles and during the growth reaction of the seed particles, methyl alcohol, ethyl alcohol, denatured ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, alcohols such as t-butyl alcohol, s-butyl alcohol, t-amyl alcohol, 3-pentanol, octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, glycerin, diethylene glycol, methyl Cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomer Ethers, such as ether alcohols such as diethylene glycol monoethyl ether as a representative.
[0102]
These organic liquids can be used alone or as a mixture of two or more. In addition, by using an organic liquid other than alcohols and ether alcohols in combination with the above-mentioned alcohols and ether alcohols, the organic liquid can be used under the condition that the organic liquid does not have solubility in the produced polymer particles. By varying the SP value of the polymer in various ways, it is possible to suppress the size of the produced particles, the union of seed particles and the generation of new particles.
[0103]
Examples of the organic liquid used in this case include hydrocarbons such as hexane, octane, petroleum ether, cyclohexane, benzene, toluene, and xylene; carbon tetrachloride, halogenated hydrocarbons such as trichloroethylene and tetrabromoethane, and ethyl ether. , Ethers such as dimethyl glycol, silioxane and tetrahydrofuran, acetales such as methylal and diethyl acetal, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexane, esters such as butyl formate, butyl acetate, ethyl propionate and cellosolve acetate , Acids such as formic acid, acetic acid, propionic acid, nitropropene, nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethylsulfoxide, dimethylforma Sulfur, such as de, nitrogen-containing organic compounds, other water is also included.
[0104]
In addition, the type and composition of the mixed solvent may be changed at the start of polymerization, during the polymerization, and at the end of the polymerization to adjust the average particle size, particle size distribution, drying conditions, and the like of the polymer particles to be produced.
[0105]
Suitable examples of the polymer dispersant used in producing seed particles or in producing grown particles include, for example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, Acids such as fumaric acid, maleic acid or maleic anhydride, or an acrylic monomer containing a hydroxyl group, for example, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-methacrylic acid Hydroxypropyl, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate Glycerin monoacrylate, glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or Esters of compounds containing a vinyl alcohol and a carboxyl group, for example, vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride and methacrylic acid chloride , Vinylpyridine, vinylpyrrolidone, vinylimidazole, ethyleneimine, etc. Limmer or copolymer, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene laurylphenyl Ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene series such as polyoxyethylene nonyl phenyl ester, and celluloses such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, or the hydrophilic monomer and styrene, α-methylstyrene, vinyl Those having a benzene nucleus such as toluene or derivatives thereof, or acrylonitrile, methacrylonitrile, Copolymers with acrylic acid or methacrylic acid derivatives such as acrylamide, and copolymers with crosslinkable monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, and divinylbenzene can also be used.
[0106]
These polymer dispersants are appropriately selected depending on the hydrophilic organic liquid to be used, the seed of the target polymer particles, and whether the seed particles or the grown particles are to be produced. In order to mainly prevent steric effects, those having high affinity and adsorptivity to the polymer particle surface and high affinity and solubility to the hydrophilic organic liquid are selected. Further, in order to three-dimensionally increase the repulsion between the particles, those having a certain length of the molecular chain, preferably those having a molecular weight of 10,000 or more are selected. However, if the molecular weight is too high, the viscosity of the solution will increase significantly, the operability and the agitation properties will be poor, and the resulting polymer will have a variation in the probability of precipitation on the particle surface, so care must be taken. It is also effective to stabilize that a part of the above-mentioned monomer of the polymer dispersant coexists with the monomer constituting the target polymer particle.
[0107]
Further, together with these polymer dispersants, metals such as cobalt, iron, nickel, aluminum, copper, tin, lead and magnesium or alloys thereof (particularly those having a particle size of 1 μm or less are preferable), iron oxide, copper oxide, nickel oxide, Inorganic oxide fine powders of oxides such as zinc oxide, titanium oxide and silicon oxide, higher alcohol sulfates, alkylbenzene sulfonates, α-olefin sulfonates, anionic surfactants such as phosphates, alkylamine salts, Amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, and quaternary ammonium salts such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridium salt, alkylisoquinolinium salt, and benzethonium chloride Nonionic surfactants such as cation salt surfactants, fatty acid amide derivatives and polyhydric alcohol derivatives of um salt type, for example, amino acids such as alanine type "for example dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine" The stability of the resulting polymer particles and the improvement in the particle size distribution can be further improved by using a combination of a type and a betaine type amphoteric surfactant.
[0108]
In general, the amount of the polymer dispersant used during the production of the seed particles varies depending on the type of the polymerizable monomer for forming the desired polymer particles, but is preferably 0.1% by weight to 10% by weight based on the hydrophilic organic liquid. , Preferably 1 to 5% by weight. When the concentration of the polymer dispersion stabilizer is low, the resulting polymer particles have a relatively large particle size, and when the concentration is high, a small particle size is obtained. Even if it is used beyond this, the effect on reducing the diameter is small.
[0109]
The vinyl monomer is soluble in a hydrophilic organic liquid and includes, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, and p-ethyl. Ethylene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene Styrenes such as pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic Isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl methyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl Α-methyl fatty acid monocarboxylic acid esters such as n-octyl acid, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylonitrile , Acrylic acid such as methacrylonitrile and acrylamide, or methacrylic acid derivatives, vinyl chloride such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride Mixtures of singly or cross made of and their containing more than 50 wt% means a mixture of mutual with monomers capable of copolymerizable therewith.
[0110]
Further, the polymer in the present invention may be polymerized in the presence of a so-called cross-linking agent having two or more polymerizable double bonds in order to enhance the offset resistance. Preferred crosslinking agents include divinylbenzene, divinylnaphthalene and aromatic divinyl compounds which are derivatives thereof, other ethylene glycol dimethacrylate, diethylene glycol methacrylate, triethylene glycol methacrylate, trimethylolpropane triacrylate, allyl methacrylate, tert-butyl. Diethylenic carboxylic acid esters such as aminoethyl methacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, all divinyl compounds such as N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone, and three The above-mentioned compounds having a vinyl group are mentioned, and these are used alone or in a mixture.
[0111]
When the growth polymerization reaction is subsequently performed using the seed particles thus cross-linked, the inside of the growing polymer particles is cross-linked. On the other hand, when the above-mentioned crosslinking agent is contained in the vinyl monomer solution used for the growth reaction, a polymer having a cured particle surface is obtained.
[0112]
In addition, for the purpose of adjusting the average molecular weight, polymerization may be performed in the presence of a compound having a large chain transfer constant, for example, a low molecular compound having a mercapto group, carbon tetrachloride, or carbon tetrabromide.
[0113]
Examples of the polymerization initiator for the monomer include azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile), and lauryl. Peroxide, benzoyl peroxide, peroxide-based polymerization initiators such as t-butyl peroctoate, peroxide-based polymerization initiators such as potassium persulfate, and those using sodium thiosulfate, amine, etc. Used. The concentration of the polymerization initiator is preferably from 0.1 to 10 parts by weight based on 100 parts by weight of the vinyl monomer.
[0114]
The polymerization conditions for obtaining the seed particles are determined according to the target average particle size and the target particle size distribution of the polymer particles, the concentration of the polymer dispersant and the vinyl monomer in the hydrophilic organic liquid, and the mixing ratio. Is done. In general, the concentration of the polymer dispersant is set high when the average particle size of the particles is to be reduced, and the concentration of the polymer dispersant is set low when the average particle size is to be increased. On the other hand, if the particle size distribution is to be made very sharp, the vinyl monomer concentration is set low, and if a relatively wide distribution is acceptable, the vinyl monomer concentration is set high.
[0115]
Particles are produced by completely dissolving a polymer dispersion stabilizer in a hydrophilic organic liquid, and then adding one or more vinyl monomers, a polymerization initiator, and, if necessary, an inorganic fine powder, a surfactant, and a dye. Add a pigment, etc., and stir with normal stirring at 30 to 300 rpm, preferably at a low speed as much as possible, and at a speed such that the flow in the tank becomes uniform using turbine-type stirring blades rather than paddle-type stirring blades. While heating, the polymerization is carried out at a temperature corresponding to the polymerization rate of the polymerization initiator used.
[0116]
In addition, since the temperature at the initial stage of polymerization has a great effect on the type of particles to be generated, it is preferable to raise the temperature to the polymerization temperature after adding the monomer, and to dissolve the polymerization initiator in a small amount of a solvent and then feed it. At the time of polymerization, it is necessary to sufficiently expel oxygen in the air in the reaction vessel with an inert gas such as nitrogen gas or argon gas. If the oxygen purge is insufficient, fine particles are likely to be generated. A polymerization time of 5 to 40 hours is required to carry out the polymerization in a high polymerization rate region, but the desired particle size, or stopping the polymerization in the state of the particle size distribution, or adding a polymerization initiator sequentially, The polymerization rate can be increased by performing the reaction under high pressure.
[0117]
After the completion of the polymerization, the polymer slurry may be used as it is in the dyeing step, or may be subjected to operations such as sedimentation, centrifugation, and decantation to remove unnecessary fine particles, residual monomers, a polymer dispersion stabilizer, and the like. The dye may be collected and dyed. However, when the dispersion stabilizer is not removed, the stability of the dyeing is high, and unnecessary aggregation is suppressed.
[0118]
The dyeing in the dispersion polymerization method is as follows. That is, the resin particles are dispersed in an organic solvent that does not dissolve the resin particles, and before or after dissolving the dye in the solvent, penetrating the dye into the resin particles and coloring, and then removing the organic solvent. In the method for producing a dyed toner, the relationship between the liquid solubility (D1) of the dye in the organic solvent and the solubility (D2) of the dye in the resin of the resin particles A is (D1) / (D2). A dye satisfying ≦ 0.5 is selectively used. This makes it possible to efficiently manufacture a toner in which the dye has penetrated (diffused) to the deep portion of the resin particles.
[0119]
Solubility herein is defined as measured at a temperature of 25 ° C. The solubility of the dye in the resin has exactly the same definition as the solubility of the dye in the solvent, and means the maximum amount of the dye that can be contained in the resin in a compatible state. The observation of the dissolution state or the precipitation state of the dye can be easily performed by using a microscope. In order to know the solubility of the dye in the resin, an indirect observation method may be used instead of the above-described direct observation method. In this method, a liquid having a solubility coefficient similar to that of the resin, that is, a solvent that dissolves the resin well may be used, and the solubility of the dye in the solvent may be determined as the solubility in the resin.
[0120]
As the dye used for coloring, the ratio (D1) / (D2) of the dye to the resin constituting the resin particles is 0.5 or less based on the solubility (D1) of the dye in the organic solvent used as described above. Need to be Further, it is preferable that (D1) / (D2) be 0.2 or less. The dye is not particularly limited as long as it satisfies the above-mentioned dissolving properties, but a water-soluble dye such as a cationic dye or an anionic dye may have a large environmental change, and the electrical resistance of the toner is lowered, and the transfer rate is lowered. Since there is a possibility that vat dyes, disperse dyes, and oil-soluble dyes are used, oil-soluble dyes are particularly preferable. Further, several kinds of dyes can be used in combination depending on a desired color tone.
[0121]
The ratio (weight) between the dye to be dyed and the resin particles is arbitrarily selected according to the degree of coloring, but usually 1 to 50 parts by weight of the dye is used per 1 part by weight of the resin particles. Is preferred. For example, when an alcohol such as methanol or ethanol having a high SP value is used as a dyeing solvent, and a styrene-acrylic resin having an SP value of about 9 is used as the resin particles, examples of the dye that can be used include the following. And the like.
[0122]
C. I. SOLVENT YELLOW (6, 9, 17, 31, 35, 1, 102, 103, 105)
C. I. SOLVENT ORANGE (2, 7, 13, 14, 66)
C. I. SOLVENT RED (5, 16, 17, 18, 19, 22, 23, 143, 145, 146, 149, 150, 151, 157, 158)
C. I. SOLVENT VIOLET (31, 32, 33, 37)
C. I. SOLVENT BLUE (22, 63, 78, 83-86, 91, 94, 95, 104)
C. I. SOLVENT GREEN (24, 25)
C. I. SOLVENT BROWN (3, 9).
[0123]
Commercially available dyes include, for example, Aizen SOT dyes Yellow-1,3,4, Orange-1,2,3, Scarlet-1, Red-1,2,3, Brown-2, Blue-1, manufactured by Hodogaya Chemical Industry Co., Ltd. 2, Violet-1, Green-1,2,3, Black-1,4,6,8, sudan dye manufactured by BASF, Yellow-140,150, Orange-220, Red-290,380,460, Blue -670 or a dialegin manufactured by Mitsubishi Kasei Corporation, Yellow-3G, F, H2G, HG, HC, HL, Orange-HS, G, Red-GG, S, HS, A, K, H5B, Violet-D, Blue- J, G, N, K, P, H3G, 4G, Green-C, Brown-A and Orient Chemical oil color, Yellow-3 , GG-S, # 105, Orange-PS, PR, # 201, Scarlet- # 308, Red-5B, Brown-GR, # 416, Green-BG, # 502, Blue-BOS, HN, Black-HBB, # 803, EE, EX, Sumiplast manufactured by Sumitomo Chemical Co., Ltd., Blue GP, OR, Red FB, 3B, Yellow FL7G, GC, Kayaron manufactured by Nippon Kayaku, Polyester Black EX-SH3, Blue of Kayaset Red-B A-2R or the like can be used. Of course, the dye is appropriately selected depending on the combination of the resin particles and the solvent used for dyeing, and is not limited to the above examples.
[0124]
The dyeing organic solvent used for dyeing the dye on the resin particles may be one in which the resin particles used do not dissolve or slightly swells. Specifically, the difference in the solubility parameter (SP value) is one. 0.0 or more, preferably 2.0 or more. For example, for styrene-acrylic resin particles, use is made of an alcohol such as methanol, ethanol or n-propanol having a high SP value, or n-hexane or n-heptane having a low SP value. If the difference between the SP values is too large, the wetting of the resin particles becomes poor, and good dispersion of the resin particles cannot be obtained. Therefore, the optimum difference between the SP values is preferably 2 to 5.
[0125]
After dispersing the resin particles in the organic solvent in which the dye is dissolved, it is preferable to stir while maintaining the liquid temperature at or below the glass transition temperature of the resin particles. This makes it possible to dye while preventing aggregation of the resin particles. The stirring may be performed using a commercially available stirrer such as a homomixer or a magnetic stirrer. Alternatively, a dye may be directly added to a slurry obtained at the end of polymerization by dispersion polymerization or the like, that is, a dispersion in which polymer resin particles are dispersed in an organic solvent, and heated and stirred under the above-described conditions. When the heating temperature is higher than the glass transition temperature, fusion between resin particles occurs. The method of drying the slurry after dyeing is not particularly limited, but may be filtration and then dried under reduced pressure or directly dried under reduced pressure without filtering. In the present invention, the colored particles obtained by air-drying or drying under reduced pressure after filtration are hardly agglomerated and are reproduced without substantially impairing the particle size distribution of the charged resin particles.
[0126]
(Dissolution suspension method)
Next, a method for producing spherical toner particles by a solution suspension method will be described.
The solution suspension method is a method in which a resin is dissolved in a solvent to form an oil phase, emulsified in an aqueous phase composed of an aqueous medium, and then the solvent in the emulsified dispersion is removed to obtain resin particles.
[0127]
As the aqueous medium, water alone may be used, or a water-miscible solvent may be used in combination. Examples of miscible solvents include alcohols (eg, methanol, isopropanol, ethylene glycol), dimethylformamide, tetrahydrofuran, cellosolves (eg, methylcellosolve), lower ketones (eg, acetone, methylethylketone), and the like.
[0128]
Examples of the resin used include polymers of styrene such as polystyrene, poly p-chlorostyrene and polyvinyltoluene and their substituted polymers; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, and styrene-vinyltoluene copolymer. Styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate Copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-based copolymers such as len-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polychlorinated Vinyl, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, Aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like can be mentioned, and they can be used alone or as a mixture.
[0129]
As a solvent that can be used for preparing an oil phase, a volatile solvent having a boiling point of less than 100 ° C. is preferable because it is easily removed. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred. The amount of the solvent to be used is usually 10 to 900 parts with respect to 100 parts of the toner composition.
[0130]
The oil phase is prepared by simultaneously adding and mixing a colorant (or a colorant masterbatch), a release agent, and a charge control agent, which are other toner compositions, when forming a dispersion in an aqueous medium. However, it is more preferable to mix them in the oil phase in advance.
[0131]
Further, other toner raw materials such as a colorant, a release agent, and a charge control agent do not necessarily need to be mixed when forming particles in an aqueous medium, and may be added after forming the particles. Good. For example, after forming particles containing no coloring agent, a coloring agent can be added by a known dyeing method.
[0132]
For dispersing the oil phase and the aqueous phase, all mixers with ordinary stirring can be used, but more preferably a homogenizer having a high-speed rotating body and a stator, a high-pressure homogenizer, and a disperser using media such as a ball mill, a bead mill, and a sand mill. Are used.
[0133]
The dispersing method is not particularly limited, but known equipment such as a low-speed shearing type, a high-speed shearing type, a friction type, a high-pressure jet type, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferred. The emulsifier having a rotating blade is not particularly limited, and any emulsifier or disperser that is generally commercially available can be used. For example, Ultra Turrax (manufactured by IKA), Polytron (manufactured by Kinematica), TK Auto Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Ebara Milder (manufactured by Ebara Corporation), TK Pipeline Homomixer TK homomix line flow (manufactured by Tokushu Kika Kogyo Co., Ltd.), colloid mill (manufactured by Shinko Pantech Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Kakoki Co., Ltd.) Batch or continuous emulsifying machine such as Fine Flow Mill (manufactured by Taiheiyo Kiko Co., Ltd.), CLEARMIX (manufactured by M-Technic), Fillmix (manufactured by Tokushu Kika Kogyo) And the like.
[0134]
When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is generally 1,000 to 30,000 rpm, preferably 5,000 to 20,000 rpm. The dispersion time is not particularly limited, but is usually 0.1 to 5 minutes in the case of a batch system. The temperature at the time of dispersion is usually 0 to 150 ° C (under pressure), preferably 10 to 98 ° C. The high temperature method is preferred because the viscosity of the dispersion becomes appropriately low and the dispersion is easy.
[0135]
In the dissolution suspension method, a method of previously dispersing solid fine particles in an aqueous medium is used for the purpose of stabilizing the dispersed oil phase.
[0136]
Further, other dispersants can be used in combination to adjust the adsorptivity of the solid fine particle dispersant to the droplets. Other dispersants can be added before emulsifying the toner composition or when removing volatile components after emulsification.
[0137]
Next, a carrier for a two-component developer when the toner is used as a two-component developer will be described.
In this case, the toner may be mixed with the magnetic carrier, and the content ratio of the carrier and the toner in the developer is preferably 1 to 10 parts by weight of the toner with respect to 100 parts by weight of the carrier.
[0138]
As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, and magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used.
[0139]
Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Also, polyvinyl and polyvinylidene resins, for example, acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins such as polystyrene resins and styrene acrylic copolymer resins, polychlorinated resins Halogenated olefin resin such as vinyl, polyester resin such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride And fluoro such as terpolymers of non-fluoride monomers including, and silicone resins.
[0140]
Further, if necessary, a conductive powder or the like may be contained in the coating resin. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide and the like can be used. These conductive powders preferably have an average particle size of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control the electric resistance.
[0141]
Next, a method for manufacturing the toner of the above-described embodiment will be described.
(Synthesis of toner binder)
724 parts of bisphenol A ethylene oxide 2 mol adduct, 276 parts of terephthalic acid and 2 parts of dibutyltin oxide are put in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introducing pipe, and subjected to polycondensation at 230 ° C. for 8 hours at normal pressure. The reaction was further performed at a reduced pressure of 10 to 15 mmHg for 5 hours to obtain a polyester resin having a peak molecular weight of 5300. 100 parts of this polyester resin was dissolved and mixed in 100 parts of ethyl acetate to obtain a solution of a toner binder in ethyl acetate.
[0142]
(Production of toner)
200 parts of the above ethyl acetate solution of the toner binder, 5 parts of carnauba wax, 4 parts of copper phthalocyanine blue pigment and 1 part of zinc ditertiary butylsalicylate were placed in a closed pot, and 1 part of zinc ditertiary butyl salicylate was added thereto using zirconia beads of 5 mm in diameter. The dispersion was dispersed in a ball mill for an hour to obtain a toner composition.
[0143]
In a beaker, 600 parts of ion-exchanged water, 6 parts of partially saponified polyvinyl alcohol, and 0.3 part of sodium dodecylbenzenesulfonate were added and uniformly dissolved and dispersed.
[0144]
Next, while maintaining the internal temperature of the beaker at 20 ° C. and stirring at 12,000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), the toner composition was charged and emulsified with stirring for 3 minutes. Then, the mixed solution was transferred to a flask equipped with a stir bar and a thermometer, and 0.3 parts of sodium lauryl sulfate was added, followed by stirring and dissolving at room temperature for 30 minutes. Then, the solvent was removed at 30 ° C. under a reduced pressure of 50 mmHg. Analysis of the dispersion by gas chromatography revealed that the residual ethyl acetate was 50 ppm based on the toner particles. 120 parts of 35% concentrated hydrochloric acid was added to dissolve the tricalcium phosphate, followed by filtration. The obtained cake was repeatedly re-dispersed in distilled water and filtered three times, and then dried under reduced pressure at 40 ° C. for 24 hours. Then, colored particles were obtained.
[0145]
To 95 parts by weight of the obtained colored particles, 3 parts by weight of silica and 2 parts by weight of titanium oxide particles were mixed with a Henschel mixer for 2 minutes and sieved to obtain a toner.
[0146]
Then, 5 parts by weight of the toner was mixed with 95 parts by weight of the silicone-coated carrier (magnetite core material) having a toner weight average particle diameter of 50 μm by a rocking mixer to obtain a two-component developer.
[0147]
As described above, by using the toner formed by the solution suspension method having a high sphericity, it is possible to configure an image forming apparatus with high image quality and reduced toner production cost.
[0148]
(Comparison of cleaning properties)
The vibration cleaning blade of the present invention was mounted, and the cleaning performance and the frictional resistance between the photoconductor (image carrier) and the blade (the surface friction coefficient of the photoconductor itself to be replaced, the photoconductor rotation torque) were evaluated and measured. .
[0149]
The conditions of charging and development were as follows, and were fixed at the time of evaluation.

[0150]
(Transfer rate evaluation)
In the evaluation (measurement) of the transfer rate, the operation is stopped while the solid image is being output on the surface of the image carrier, and the toner images between the developing section and the transfer section and between the transfer cleaning section are removed. The image was transferred to white paper with a scotch tape (trade name, manufactured by Sumitomo 3M Co., Ltd.), and measured with a Macbeth reflection densitometer RD514 (trade name).
[0151]
At this time,
Tape density between development part and transfer part: Ddt
Tape density between transfer part and cleaning part: Dtc
Density of scotch tape transferred to white paper: Dref
The transfer efficiency was calculated by the following equation (1).
[0152]
(Equation 1)

[0153]
(Cleaning evaluation)
The cleaning property was evaluated using a scotch tape in the same manner as the above-described transfer rate.
The toner (transfer residual toner) after the transfer process on the surface of the photoreceptor, which is an image carrier, is transferred to white paper with a scotch tape (trade name, manufactured by Sumitomo 3M Co., Ltd.), and the same is applied to the Macbeth reflection densitometer Measured with RD514 type (trade name), the difference between the blank (white paper with only scotch tape) and 0.01 or less is considered good ("○" in the evaluation result table). Those exceeding this (high concentration) were regarded as NG (poor).
[0154]
The actual output is 0.1 mg / cm ² Is prepared, and this is output for 50,000 A3 sheets in the vertical direction. When the output of 50,000 sheets has been completed, an image pattern that becomes a solid image is output and evaluated halfway as shown in the above-described methods of measuring the transfer rate and the cleaning rate.
[0155]
(Measurement of resonance frequency)
As shown in FIG. 9, a vibration measuring device 41 for examining a resonance frequency was arranged, and an output signal of the vibration measuring device 41 was taken into a personal computer for vibration analysis. The vibration measuring device 41 measures frequency characteristics during vibration using a measurement principle called laser Doppler measurement. The laser Doppler vibrometer actually used is as follows.
Laser Doppler Vibrometer: (PI) Polytec
Laser Doppler displacement meter OFV-303 (trade name)
[0156]
Then, FFT analysis was performed using vibration analysis software of the vibration analysis personal computer 52 to measure which frequency has a resonance frequency.
[0157]
In order to shorten the time for detecting and measuring the resonance frequency, noise having a certain amplitude may be input as a waveform applied to the piezoelectric element. During a normal cleaning operation, a sine wave or a rectangular wave is input and driven, but when a resonance frequency is detected, noise (often called white noise) is input.
[0158]
(Friction resistance and resonance frequency)
A description will be given of a change in resonance frequency when the frictional resistance is intentionally changed in the image forming apparatus including the laser Doppler vibrometer described above.
It is difficult to directly measure the frictional resistance between the blade and the image carrier by incorporating the frictional resistance measuring device into an actual image forming apparatus. Therefore, here, a configuration will be described in which the drive frequency of the vibrating means is set and controlled based on the friction coefficient of the image carrier, which is relatively easy to measure, or the rotational torque of the image carrier. Note that both the coefficient of friction and the torque have a correlation with the frictional resistance, and in the fundamental sense, both have the same value.
[0159]
(1) Coefficient of friction of photoconductor (image carrier)
The initial friction coefficient of the photosensitive member was measured (Euler belt method for paper), and the vibrating cleaning blade 20 shown in FIG. 3 was driven under a constant condition (the amplitude of white noise was the same). FIG. 10 shows the measurement results of the resonance frequency at that time.
[0160]
As shown in FIG. 10, it can be seen that there is a resonance frequency at which the amount of vibration displacement increases around 24 kHz (the exact frequency at this time is frequency b). However, it can be seen that the frequency at which the displacement is maximum changes within a width (frequency a, b, c) of about 1 kHz due to the difference in the friction coefficient of the photoconductor. Although the details of this cause are not yet clear, the increase in the coefficient of friction of the photoreceptor causes the cleaning nip at the blade tip to be brought downstream, and as a result, the driving conditions of the piezoelectric element are reduced. Even if the same, the resonance frequency is changed by the combination of the blade and the photoconductor, so it is presumed that such a result is obtained.
[0161]
Next, for each value of the coefficient of friction, the resonance frequency obtained earlier is used as the drive frequency, and the result of determining the cleaning property on the photoconductor when a sine wave is input as a waveform is fixed at the frequency b. Table 1 also shows the results when only the friction coefficient of the photosensitive member was changed.
[0162]
[Table 1]

[0163]
According to Table 1, even if the friction coefficient of the photosensitive member changes, the cleaning property is good if the piezoelectric element is driven at the resonance frequency generated at that time, but it is fixed even if the friction coefficient of the photosensitive member changes. It can be seen that the cleaning performance is not improved by driving at the frequency of.
[0164]
As described above, a certain amount of vibration displacement is required for cleaning with the vibrating cleaning blade as described above, and it is better to use the resonance frequency to achieve this. If the resonance frequency cannot be used, it is possible to vibrate under certain driving conditions.However, since the vibration is very small and the voltage required for driving tends to be large, the load on the piezoelectric element is reduced. In addition, the power source required for driving is not preferable because a large capacity is additionally required.
[0165]
The method of changing the resonance frequency based on the coefficient of friction of the photoreceptor is a case where an image is actually formed by an image forming apparatus. When a drive circuit that cannot change the frequency is mounted on the device, or when the resonance frequency spreads at a large rate (a blade whose skirt is larger than the frequency at the center position), the piezoelectric element is placed near the resonance frequency. When driven, a certain amount of vibration displacement can be secured and the cleaning property is also improved. Therefore, the resonance frequency determined by the combination of the initial photoreceptor surface and the vibration cleaning blade is detected (measured), and the resonance frequency is detected. It is preferable that the piezoelectric element is driven by the above.
[0166]
(2) Image carrier rotation torque
A rotating torque meter was attached to a shaft of a drum-shaped image carrier mounted in the image forming apparatus shown in FIG. 2, and torque was measured during a rotating operation. During this measurement, only the cleaning blade 23 provided with the vibrating means was in contact with the image carrier, and the rotational torque was measured. Note that, as described above, the evaluation of the cleaning property incorporated steps necessary for visualizing the charging step, the developing step, and the transfer step. As a measuring means (detecting means) corresponding to the frictional resistance between the blade and the image carrier, incorporating the torque meter into the image forming apparatus is optimal in that the frictional resistance is directly examined.
[0167]
Here, the measurement was performed on the drum-shaped OPC, but the measurement can be similarly performed on the belt-shaped photoconductor. However, in order for the blade to contact and clean the toner, contact with the photoreceptor is necessary. Therefore, it is preferable to dispose the torque meter as close to the blade as possible. In the case of a belt photoreceptor, since a certain amount of pressure between the belt and the blade is required for cleaning, a roller or the like for suspending the belt is often provided. The torque meter is preferably mounted on the shaft of the suspension roller closest to the blade.
[0168]
As in the case of the change in the friction coefficient of the photosensitive member, the vibration analysis and the cleaning performance were evaluated when the rotation torque of the photosensitive member was intentionally changed and when the vibration cleaning blade 20 was operated. Also in this case, white noise was input to the piezoelectric element and vibration analysis was performed on a personal computer in the same manner as described above.
[0169]
The results of the vibration analysis are not shown, but as shown in the figure, as in the previous results, due to the difference in torque, around 24 kHz (assuming that the exact frequency at this time is frequency e, the frequency e here is the frequency described above). It became the same value as b.) It was found that there was a resonance frequency at which the amount of vibration displacement increased. However, it was found that, due to the difference in torque, the frequency at which the displacement was the maximum changed in a width (d, e, f) of about 1 kHz, as before.
[0170]
It is considered that the reason for this cause is the same as the friction coefficient of the photoconductor itself. That is, it is considered that the phenomenon that the torque increases is caused by an increase in the load on the blade nip and the surface of the photoconductor. It is presumed that the load is caused by the nip portion for cleaning being brought downstream.
[0171]
Next, for each torque value, the resonance frequency obtained earlier is used as the drive frequency, and the result of determining the cleaning property on the photoconductor when a sine wave is input as a waveform is fixed at the frequency e. Table 2 also shows the results when only the torque value was changed.
[0172]
[Table 2]

[0173]
According to Table 2, even if the torque of the rotation of the photoconductor changes, the cleaning property is good if the piezoelectric element is driven at the resonance frequency generated at that time, but the torque of the rotation of the photoconductor changes. It can be seen that the cleaning performance is not improved when driven at a fixed frequency. The cause is considered to be the same as the reason described above.
[0174]
As described above, the method of changing the resonance frequency by changing the torque when the photoreceptor rotates is a case where an image is actually formed by an image forming apparatus, and when a certain degree of durability is provided, When the surface of the photoconductor changes easily due to toner adhesion, etc., and the frictional force between the blade and the photoconductor changes easily, the optimum resonance that can secure a certain amount of vibration displacement by estimating the resonance frequency change from the torque meter change It is possible to optimize the cleaning by changing the driving conditions to the frequency.
[0175]
(Cleaning and resonance frequency)
Conventional methods for controlling the driving of the piezoelectric element that constitutes the vibrating cleaning blade use a laser Doppler vibrometer for the detection method provided in the image forming apparatus, but it is necessary to further reduce the cost. It is possible to set the optimum cleaning state by estimating the resonance frequency from the cleaning performance itself. The method will be described.
[0176]
Until now, as shown in Table 1 and Table 2, even if the piezoelectric element is driven at a frequency other than the resonance frequency determined by the correlation between the vibrating cleaning blade and the photosensitive member, no vibration displacement amount can be obtained, resulting in poor cleaning performance. I understood. Then, the change in the resonance frequency is read from the evaluation result of the cleaning performance, and the cleaning performance is poor, and there is a tendency to affect the output image (for example, on the output image and also on the non-image portion). The cleaning property can be improved by controlling the frequency for driving the piezoelectric element to a value close to the resonance frequency (for example, when toner adheres) and securing the vibration displacement amount.
[0177]
In this case, as shown in FIG. 10, it is not known whether the frequency has moved to the front or the back of the resonance frequency. If there is a possibility that the frequency has changed), several sheets are output, and if the cleaning performance is further deteriorated, the drive frequency may be controlled to the opposite side. At this time, a method is simple in which the operating person directly looks at the actually output image and reflects the determination result of the cleaning property to the image forming apparatus.
[0178]
When the image forming apparatus is a printer, the setting conditions can be changed by a printer driver on the host side that transfers data to the printer.
[0179]
Further, if it is desired to automate the process, a small cost is required, but a line sensor for detecting the remaining toner is arranged in the rotation direction of the photoconductor and downstream of the vibration cleaning blade, and the cleaning on the photoconductor surface is performed. The cleaning performance can be improved or maintained by detecting the cleaning performance and inputting the result as a signal to the main control unit to change the driving frequency of the vibrating means.
[0180]
As described above, it is possible to change the driving frequency of the piezoelectric element based on the result of cleaning, whether it is automation or non-automation requiring human setting, and to set the optimum conditions for cleaning.
[0181]
As described above, the driving unit can change the driving frequency, so that the vibration unit can be driven at a driving frequency corresponding to the resonance frequency.
[0182]
Then, by setting the drive frequency based on the frictional resistance between the blade member and the image carrier, the frictional resistance that is correlated with the resonance frequency that is difficult to actually measure in the apparatus can be used, and the resonance can be easily performed. Driving can be performed at a driving frequency corresponding to the frequency, so that conditions optimal for cleaning can be set.
[0183]
In this case, the driving frequency is set (automatically, semi-automatically, or manually set) based on the friction coefficient of the surface of the image carrier that is correlated with the frictional resistance, so that the frictional resistance can be simplified. It is possible to grasp (simple grasp with low-durability image carrier: detect the image carrier where film peeling progresses), with a simple configuration without having a large-scale measuring device. It is possible to easily set and control the drive frequency to the drive frequency corresponding to the resonance frequency and to drive, and to set the optimum conditions for cleaning.
[0184]
Further, by setting the drive frequency based on the rotational torque of the image carrier that is correlated with the frictional resistance, it is possible to improve the responsiveness to the temporal change in the frictional resistance (and to improve the durability). A high image bearing member capable of detecting the frictional resistance of a high image bearing member and having a large variation in the surface state of the image bearing member over time, or a highly durable image bearing member without replacement of the image bearing member. Even in the image forming apparatus, the rotational load can be accurately grasped by the rotational torque, and the setting of the driving frequency to be driven can be controlled in accordance with the fluctuation of the load, so that the optimum conditions for cleaning can be set.
[0185]
Further, by setting the driving frequency based on the detection result of the cleaning property, it is possible to detect a change in the resonance frequency of the cleaning blade by the vibrating means in the image forming apparatus, and the optimum condition for cleaning is obtained. Can be set. In general, the cleaning performance is evaluated based on the amount of toner on the photoconductor after passing through the blade.
[0186]
Next, another example of the vibration cleaning blade 20 of the cleaning device 16 will be described with reference to FIGS.
In this embodiment, a laminated piezoelectric element is used as the vibration means 33 for applying vibration to the vibration member 22. Since the laminated piezoelectric element has a high natural frequency of 50 to 100 kHz and a very large displacement force, the laminated piezoelectric element is high even when the thickness of the vibration member 22 is increased by using the laminated piezoelectric element. A configuration capable of responding up to the frequency becomes easy.
[0187]
Here, the laminated piezoelectric element constituting the vibration means 33 has, for example, a 100 μm-per-layer piezoelectric layer 33 a and an internal electrode 33 b alternately laminated, and the internal electrodes 33 b are alternately drawn to both end faces and are connected to an end face electrode (external electrode). Electrodes), and uses a displacement in the d33 direction, which is a displacement in the laminating direction.
[0188]
It is to be noted that a configuration in which a displacement in a plane direction perpendicular to the laminating direction of the plurality of laminated layers using the laminated piezoelectric element, that is, a displacement in the d31 direction may be used. And the cost of the driver (drive circuit) can be reduced. When this configuration is adopted, the configuration is the same as that of FIG. 9 except for the laminated piezoelectric element constituting the vibration means 23.
[0189]
Here, the vibrating member 22 is a thin plate that can be elastically deformed, and the fixed end of the vibrating member 22 is fixed to a fixing member 35 that is a highly rigid holder having a support portion 35a that faces the vibrating member 22. The laminated piezoelectric element, which is the vibration means 33, is disposed between the supporting portion 35 a of the member 35 and the vibration member 22. The blade member 21 is disposed in the distal end region of the vibrating member 22 opposite to the vibrating means 233 so that the vibration from the vibrating means 33 is transmitted through the vibrating member 22.
[0190]
In this manner, by providing the vibration means between the fixed portion and the vibration member, vibration can be efficiently transmitted to the vibration member.
[0191]
Further, as shown in FIG. 12, a plurality of vibration means 33 are provided in the width direction of the image carrier 1. In the case of the blade member 21 having a relatively small width, a single vibrating means 33 may be used if a laminated piezoelectric element having a large sectional area is used.
[0192]
Next, a process cartridge according to the present invention including the cleaning device according to the present invention will be described with reference to FIG. FIG. 2 is a schematic sectional view of the process cartridge.
[0193]
The process cartridge 50 includes a plurality of components, such as an image carrier 51, a charging unit 52, a developing unit 54, and a cleaning device 56 according to the present invention, which are integrally connected as a process cartridge. The process cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.
[0194]
By providing the cleaning device 56 in a detachable process cartridge, the maintenance can be improved and the unit can be easily exchanged with another device.
[0195]
Next, a color image forming apparatus using the process cartridge according to the present invention will be described with reference to FIG.
This image forming apparatus is a color image forming apparatus in which the above-described process cartridges 50 of respective colors are juxtaposed along a transfer belt (image carrier) 61 extending horizontally.
[0196]
Four process cartridges 50 are arranged for each of yellow, magenta, cyan, and black. The developed toner on the image carrier 61 developed by each process cartridge 50 is sequentially transferred to a transfer belt 61 to which a horizontally extending transfer voltage is applied.
[0197]
In this manner, the images of yellow, magenta, cyan, and black are formed, transferred onto the transfer belt 61 in a multiplex manner, and transferred collectively to the transfer material 18 by the transfer unit 62. Then, the multiple toner image on the transfer material 18 is fixed by a fixing device (not shown). Although the process cartridges 50 have been described in the order of yellow, magenta, cyan, and black, they are not specified in this order and may be arranged in any order.
[0198]
Normally, a color image forming apparatus has a plurality of image forming units, so that the apparatus becomes large. In addition, when each unit such as cleaning or charging is broken down individually or when the replacement time comes due to the end of its life, the device is complicated and the replacement of the unit is very troublesome.
[0199]
Therefore, as in the present embodiment, the components of the image bearing member, the charging means, and the developing means are integrally connected as a process cartridge 50, so that a small and highly durable color which can be replaced by a user. An image forming apparatus can be provided.
[0200]
【The invention's effect】
As described above, according to the cleaning device of the present invention, the vibration unit for vibrating the cleaning blade member is driven with the resonance frequency as the drive frequency, so that the vibration amount can be secured. Cleaning performance can be maintained.
[0201]
According to the image forming apparatus of the present invention, since the cleaning device of the present invention is provided, it is possible to form a high-quality image without cleaning failure.
[0202]
According to the process cartridge of the present invention, since the cleaning device of the present invention is provided, it is possible to form a high-quality image without cleaning failure.
[0203]
According to the image forming apparatus of the present invention, since the plurality of process cartridges of the present invention are provided, it is possible to form a high-quality color image without cleaning failure.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a cleaning mechanism of a cleaning device according to the present invention.
FIG. 2 is a schematic configuration diagram of an image forming apparatus according to the present invention including the cleaning device according to the present invention.
FIG. 3 is an enlarged explanatory view of a main part of a vibrating cleaning blade showing an example of a cleaning device of the image forming apparatus.
FIG. 4 is an enlarged explanatory view of a main part of FIG. 3;
FIG. 5 is an explanatory front view of the vibrating cleaning blade.
FIG. 6 is an explanatory view of the vibrating cleaning blade as viewed from a distal end side.
FIG. 7 is an explanatory diagram illustrating an example of a drive control system of the cleaning device.
FIG. 8 is an explanatory diagram for explaining the circularity of the toner;
FIG. 9 is an explanatory diagram for explaining measurement of a resonance frequency;
FIG. 10 is an explanatory diagram showing an example of a measurement result of a relationship between a frequency and a displacement amount.
FIG. 11 is an explanatory view for explaining another example of the vibrating cleaning blade of the cleaning device according to the present invention.
FIG. 12 is an explanatory diagram of the vibrating cleaning blade in a width direction of an image carrier.
FIG. 13 is an explanatory diagram for explaining a process cartridge according to the present invention.
FIG. 14 is a schematic configuration diagram of an image forming apparatus according to the present invention including the process cartridge according to the present invention.
FIG. 15 is an explanatory diagram for explaining a conventional cleaning blade.
FIG. 16 is an enlarged explanatory view of a main part showing a state when the image carrier of the cleaning blade is moving.
FIG. 17 is an explanatory diagram for explaining a cleaning mechanism of pulverized toner using the cleaning blade;
FIG. 18 is an explanatory diagram for explaining a stick-slip motion in a cleaning mechanism of the pulverized toner using the cleaning blade.
FIG. 19 is an explanatory view for explaining the mechanism of occurrence of defective cleaning of spherical toner using the cleaning blade.
FIG. 20 is an explanatory diagram illustrating the mechanism of occurrence of defective cleaning of spherical toner using the cleaning blade.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Blade member, 11 ... Image carrier, 20 ... Vibration cleaning blade, 21 ... Blade member, 22 ... Vibration member, 23 ... Vibration means, 28 ... Drive circuit, 50 ... Process cartridge.

Claims (11)

A cleaning device for cleaning toner remaining on the surface of an image carrier of an image forming apparatus, comprising a vibrating member having one or more vibrating means attached thereto, the vibrating member being long in a width direction, and at least one of the vibrating members. A widthwise long blade member attached to the distal end region; and a driving unit for driving the vibrating unit at a driving frequency of a resonance frequency, wherein the vibration member vibrates the blade member and the image carrier of the blade member. A cleaning device for applying a pressing force to the cleaning device. 2. The cleaning device according to claim 1, wherein said driving means is capable of changing said driving frequency. 3. The cleaning device according to claim 2, wherein a driving frequency of the driving unit is set based on a frictional resistance between the blade member and the image carrier. 4. The cleaning device according to claim 3, wherein a driving frequency of the driving unit is set based on a friction coefficient of the surface of the image carrier. 4. The cleaning device according to claim 3, wherein a driving frequency of the driving unit is set based on a rotation torque of the image carrier. 4. The cleaning device according to claim 3, wherein the driving frequency of the driving unit is set based on a result of detecting the cleaning property. 7. The cleaning device according to claim 1, wherein said vibrating means is a piezoelectric element. 8. The cleaning device according to claim 1, wherein the toner is a polymerized toner produced by a polymerization method. 8. A process cartridge including at least one of an image carrier, a charging unit, a developing unit, and a transfer unit, and a cleaning unit, wherein the cleaning unit is detachable from the image forming apparatus main body, wherein the cleaning unit is any one of claims 1 to 7. A process cartridge characterized by being a cleaning device of (1). An image forming apparatus for forming an image by using an electrophotographic method, comprising a cleaning device according to any one of claims 1 to 7 for cleaning toner remaining on the surface of an image carrier. Image forming device. An image forming apparatus for forming a color image, comprising a plurality of the process cartridges according to claim 8.

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