JP4046325B2 - Image forming apparatus and process cartridge - Google Patents

Description

【０２１２】
また、本発明に係る前記加振ブレードの加振手段を構成する圧電素子に対する駆動電圧の印加は、上述したように、パルス信号を発生させるための、ファンクションジェネレータと、これから発生した信号を増幅させる電源を通して行い、実際に圧電素子に印加される電圧を確認するため、増幅された電圧を分岐させ、これをオシロスコープによってモニタした。
【０２１３】
本発明が目的とするクリーニング性の評価、及び球形トナーを使用したときに向上される転写率について次のように評価を行った。
（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）で白い紙に転写させて、それをマクベス反射濃度計ＲＤ５１４型で測定した。
【０２１４】
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。
【０２１５】
【数１】

【０２１６】
（クリーニング評価）
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）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。
【０２１７】
（トナーの円形度の違いによる比較）
前述した第２実施形態に係る加振ブレード２０（図８及び図９）を搭載した画像形成装置で評価を行った。クリーニング性は、作像動作時の初期では、その良否の判断が困難であるため、従来のブレードクリーナと溶解懸濁重合で作られたトナーＣでクリーニング不良の発生が明らかに確認されたＡ３用紙相当で５００００枚後での評価を先に記載したトナーＡ〜Ｇで評価を行った。
【０２１８】
なお、ブレードクリーナとしては、従来ブレード（ブレード部厚み：３ｍｍ）と第２実施形態に係る加振ブレード２０（振動部材厚み：０．３ｍｍ、ブレード部材厚み：０．２ｍｍとした。）を用いて、共に感光体（像担持体１１）に対する押し当ての圧力（当接圧）を７０ｇ／ｃｍ²で統一した。また、共にブレード部材はポリウレタンゴムとした。バルクとしての硬度は、ＪＩＳ-Ａで約７０°であった。第２実施形態に係る加振ブレード２０の積層型圧電素子３３には、全て電圧Ｖｐｐ：２０Ｖ、周波数：２０ｋＨｚの駆動電圧を印加した。
【０２１９】
実際の出力は、感光体上に付着量が０．１ｍｇ/ｃｍ²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。
【０２２０】
以上の評価結果を表１に示している。なお、表１のクリーニング性の欄における「本発明ブレード」は上記のとおり第２実施形態に係る加振ブレード２０を意味している。また、「ＮＧ１」は約１０００枚の出力で、紙上にクリーニング不良による地汚れが発生したことを、「ＮＧ２」は約３０００枚の出力で、紙上にクリーニング不良による地汚れが発生したことを、「ＮＧ３」は約２５００枚の出力で、紙上にクリーニング不良による地汚れが発生したことを、それぞれ意味している。
【０２２１】
【表１】

【０２２２】
この表１より、粉砕トナーであるトナーＤ及びＥについては、振動のない従来のブレードでもクリーニング性は維持されていること分かるが、機械処理、あるいは加熱処理で円形度を高くしたものでは、従来ブレードではクリーニングの機能が維持されないことが分かる。
【０２２３】
また、転写率に関しては、先に記載したように、円形度の高いものは転写効率が９５％前後と高い値を示し、この点から高画質であることが予測できるが、円形度の低いものは９０％前後と低くなっている。クリーニング性の点から良好であった、トナーＤ及びＥはクリーニング性は良好であるものの、転写率を比較すると低く、画質の点からは好ましくないことが分かる。
【０２２４】
この表１から明らかなように、第１の発明では高い円径度をもつ球形トナーに対し、ブレード部の振動があることによって、従来のブレードクリーニングと比較し、クリーニング不良の発生を防止することができ、また、繰り返し使用によってもクリーニング性を維持することが可能となることが分かる。
【０２２５】
次に、上記評価で最も転写率の高かった溶解懸濁重合法で作られたトナーＣを用いて、従来のブレードクリーニングを含め、第１ないし第３実施形態に係る各加振ブレードのクリーニング性を評価した。
【０２２６】
先ず、印加する電圧Ｖｐｐの大きさについての評価について説明する。
上述した評価実験と同じように、各ブレードで５００００枚相当の出力を行った後にクリーニング性の評価を行った。このとき、駆動電圧の周波数は２０ｋＨｚで固定し、第１ないし第３実施形態の加振ブレードについては、圧電素子に印加する駆動電圧の電圧Ｖｐｐを５，２０，３０Ｖと変化させてそれぞれ評価し、同時にレーザドップラ変位計でブレード部の先端部の変位量を測定した。
【０２２７】
なお、加振時のブレードの変動量については、クリーニング装置の上であって、振動部材あるいは、ブレード部材の上から、上述したようにレーザドップラ変位計を使い、光学的に変位量を測定した。測定には、いずれも次のグラフテック株式会社製の装置を使用した。
レーザドップラ振動復調ユニット ＡＴ３５００
センサユニット ＡＴ００２１
【０２２８】
この結果を表２に示している。なお、表２中、「ＮＧ４」は出力初めから紙上にクリーニング不良による地汚れが発生したこと、「ＮＧ５」は約１００枚の出力で紙上にクリーニング不良による地汚れが発生したことをそれぞれ意味する。
【０２２９】
【表２】

【０２３０】
この表２に示すように、第１の発明に係る加振ブレード（ブレードクリーニング）でも、加振手段である圧電素子への印加電圧が低い場合、クリーニング性を維持することができず、従来ブレードとほぼ同等になる。また、第１ないし第３実施形態の加振ブレードの場合、印加電圧の増加に伴って変位量も増加することが分かる。従来ブレードについても変位量を測定したが、計測器の測定下限値である０．０１μｍ以下の変位量であった。
【０２３１】
第１ないし第３実施形態の加振ブレードの場合、圧電素子に対する印加電圧を上げていけば、いずれの構成であってもクリーニング性は維持される。これを、レーザドップラ変位計による変位量と関係付けて推察する。
【０２３２】
先のメカニズム及び従来出願されていた公知技術によると、従来のブレードでもスティック―スリップ現象が発生し、微小な振動がクリーニング性に寄与するとされているが、球形トナーでは、その振動量が小さいためにトナーのすり抜けが起こり結果的にクリーニング不良を発生させると考えられる（トナー壁ができない）。
【０２３３】
レーザドップラ変位計の結果からも分かるように、振動による変位量が小さい場合には、球形トナーのクリーニングは不可能と考えられる。圧電素子へ印加する電圧も、球形トナーをクリーニングさせるに必要な振動量の下限値があることが表２から分かる。
【０２３４】
したがって、表２から明らかなように、第１の発明では高い円形度をもつ球形トナーに対し、ブレード部に対してある一定量以上の振動を与えることによって、従来のブレードクリーニングと比較し、クリーニング不良の発生を防止することができる。また、繰り返し使用によってもクリーニング性を維持することが可能となる。
【０２３５】
次に、感光体（像担持体）に対するダメージという点で評価した。
先の評価実験と同じように、各ブレードで５００００枚相当の出力を行った後にクリーニング性の評価を行った。この時、印加する電圧Ｖｐｐは２０Ｖ、周波数は２０ｋＨｚとして固定した。また、トナーは溶解懸濁重合法で作られたトナーＣを用いた。
【０２３６】
この評価では、ブレードの感光体へのダメージをより顕著に明らかにするために、ＯＰＣを使って、５００００枚出力後にその感光層の削れ量を測定した（アモルファスシリコン系感光体は、削れにくいため、感光体へのダメージ評価が明らかにならないためである。）。この結果を表３に示している。
【０２３７】
【表３】

【０２３８】
この表３に示すように、第１の発明に係る加振ブレードでは膜削れ量が２μｍ程度であったのに対し、従来ブレードでは、その約倍の４μｍ程度と増加していることが分かる。
【０２３９】
この理由としては、従来ブレードではスティック―スリップ現象で微小な振動はあるが、振動量としては小さく、感光体への接触時間が本発明に係る加振ブレードに比べて長いため、結果としてブレードと感光体との摺擦力（時間的に積分した摺擦力、と考えても良い。）が増加して、感光層の膜削れ量が増えたものと考えられる。
【０２４０】
また、以上の比較をアモルファスシリコン系感光体で行った場合、第１実施形態に係る加振ブレード、従来ブレードいずれも膜削れ量としての変化は１μｍ以下と計測器の測定限界以下であったため比較は困難であった。しかし、表面が硬質のアモルファスシリコン系感光体であっても、従来のＯＰＣと比較し微小とはいえ、膜削れ、傷の発生は生じているため、第１の発明に係る加振ブレードでは従来のブレードに比べて、感光体の耐久性を向上させるという点で効果があると推測される。
【０２４１】
このように、振動量が多い第１の発明に係る加振ブレードでは、感光体の膜厚の変化、言いかえれば削れ量も低く、像担持体へのダメージと言う点で、有効であり結果的に耐久性を向上させることができる。
【０２４２】
次に、加振ブレードの加振手段の動作タイミング及び振動幅について説明する。
像担持体上のトナーをクリーニングすることで、ブレード部材先端には、クリーニング時のトナーの溜まりができることになる。なお、この場合は、円形度の高い球形に近いトナーのブレードによるクリーニングが可能か、否かのメカニズムで述べたことよりも、もっと広い幅でのトナーの溜まりであって、量が多くなればブレード表面に乗り上げることもある。このトナー溜まりは場合によってはブレードの動きを制約したりすることがある。
【０２４３】
例えば、トナー固着の起きにくいトナーであってもブレードと感光体との間で圧接により、固着の可能性があったり、トナーに内包される添加剤、例えばワックスがブレードにより引き伸ばされて感光体表面のフィルミングといったことも起きる。このため、定期的にトナー溜まりを解除し、できるだけ少なくするほうが耐久性向上の面では好ましい。そのため、加振手段によるブレード部材の振動量（変位量）を変化させることが好ましい。
【０２４４】
そこで、前述したように、作像の条件、例えば、トナー消費量、環境条件、像担持体上のトナー付着量、印刷枚数（作像回数）を検出して、この検出結果に基づいて加振手段を駆動制御する。
【０２４５】
この場合、通常の作像のタイミングで圧電素子の振動量を変化させるとクリーニングの条件が変わってしまうためクリーニング不良を起こすことが予測される。そこで、非作像時には振動量が大きくなるように制御して、トナー溜まりを解消し、作像時にはクリーニング条件を維持してクリーニング不良の発生を防止するため振動量が小さくなるように制御する。なお、この振動量の制御は上述したように加振手段に印加する駆動信号の電圧値を変化させればよい。
【０２４６】
また、高速で出力される画像形成装置の場合にはトナー消費量も多いことが予測されるため、ブレードの振動量を大きくさせるだけではなく、トナー溜まりを解消するための補助部材を配置して行うこともできる。前記評価実験ではブレードの先端にブラシ（φ８）を配置してトナー溜まりを解消させた。
【０２４７】
次に、第２の発明に係る実施形態について説明する。
先ず、画像形成装置の構成は、第１の発明の実施形態（図２参照）の画像形成装置の構成において、出力される画像でトナーで顕像化させるに必要な面積（画像面積）をカウントし、単位面積当たりのトナーを量を見積もるための信号を主制御部に取り込んでいる。
【０２４８】
また、主制御部には、像担持体１１を回転させるために必要なモータの回転トルクを検出する検出手段の信号、あるいは当該モータに対する駆動電流を検出する検出手段の信号をも入力している。
【０２４９】
また、クリーニング装置１６の構成については、第１の発明のクリーニング装置１６の第１実施形態及び第２実施形態として説明した構成を用いている。
【０２５０】
さらに、クリーニング装置１６を構成する加振ブレード２０の加振手段２３に対する駆動制御に関しても第１発明の実施形態で説明したとおりである。
【０２５１】
そこで、第２の発明が目的とするブレード部材と像担持体との摩擦抵抗の低減によるクリーニング性の維持、向上について説明する。
まず、トナーとしては、前記第１の発明の実施形態で説明した「トナーＣ」を用いた。なお、第２の発明は球形トナーを用いる画像形成装置、クリーニング装置等に限るものではない。
【０２５２】
摩擦抵抗力の測定について説明する。第２の発明に係る加振ブレードを用いた場合、振動部材２２に対する加振手段２３による加振によって、ブレード部材２１と像担持体１１間との摩擦抵抗力が変化する。
【０２５３】
ここで、直接的に摩擦抵抗力を測定する方法として、実験的に表面性試験機を使って評価した。用いた試験機は、表面性試験機：トライボギア HEIDON TYPE:14DR（新東科学製）である。
【０２５４】
この装置を用い、実験的に加振によるブレード部材と像担持体１１との間の摩擦抵抗力を測定した。この実験の際の模式図を図１３に示している。
ここでは、表面性試験機に取り付ける加振ブレードは、第１の発明の第２実施形態で説明したように、加振手段２３として圧電素子３３を振動部材２２の背面に取り付けたものを用いている。ブレード部材２１に当接する部材としては、表面が洗浄されたガラス面５１を用いた。通常の作像工程では、ブレード部材２１と像担持体１１の感光層とが接触するが、まずブレード部材２１に振動を与えることが摩擦抵抗力とどのように関係があるのか明らかにするため、また、洗浄することによって均一表面を維持することで摩擦抵抗力の測定環境が安定するため、表面性試験機にはガラスを採用し、ブレード部材２１とガラス面５１との摩擦抵抗力を測定した。
【０２５５】
表面性試験機は、ブレード部材２１に一定の加重（ガラス面に対して垂直方向）を掛けた時に、一定方向及び速度でガラス面５１を取り付けたステージ５２を動かしたときに横方向に掛かる力を試験機に取り付けられた歪ゲージ５３によって、摩擦力として測定する。この時、歪ゲージ５３に掛かる力、ブレードとガラス面との摩擦抵抗力は、リアルタイムでアラナイジングレコーダ５４に記録される。
【０２５６】
このアラナイジングレコーダ５４に記録された（以下、チャートとする）一例を図１４に示している。同図では、ステージ５２が停止した状態から摩擦抵抗力の測定例を示している。最初、ステージ５２が停止した状態（Ａ領域）では、摩擦抵抗力が０であるため、チャート中も０の値を示している。ステージ５２が動き始めると同図中のＢ領域ではステージ５２が動き始め、摩擦抵抗力が上がることがチャート上でも現れている。Ｃ領域では、動き始め、ブレード部材２１とガラス面５２との摩擦抵抗力がほぼ一定値を維持しながら動いている状態である。しばらくすると、ステージ５２は所定の移動距離に達した後、停止する。
【０２５７】
このチャート上の各領域において、Ｂ領域の最初の段階であって、摩擦抵抗力が最大になるところは静止摩擦係数に相当する箇所で、Ｃ領域のほぼ摩擦抵抗力が一定になるところは、動摩擦係数に相当する箇所である。
【０２５８】
実際の作像工程では、ブレード部材２１と像担持体１１とは相対的に移動しているため、Ｃ領域の摩擦抵抗力の値をもって、クリーニングブレードとガラス面との摩擦抵抗力とした。
【０２５９】
以上の方法によって、実際に加振手段２３を備えたクリーニングブレード部材２１を使って、加振条件を変化させた時の摩擦抵抗力を測定した結果を次に説明する。
表面性試験機の測定条件は、次のとおりとし、一定値とした。
ステージ移動速度 １０ｍｍ/ｓｅｃ
ブレード加重 ２５ｇ/ｃｍ
ブレード長さ ３ｃｍ（トータルの加重としては７５ｇ）
【０２６０】
加振手段２３を構成する圧電素子に印加するバイアス（駆動バイアス）を、周波数、交番電圧（Ｖｐｐ）を変えたときのＣ領域の摩擦抵抗力の値の変化を図１５及び図１６に示している。摩擦抵抗力の値としては、Ｃ領域であってステージの動作が安定した時間（図１４では、ステージの動き始めから２秒後から４秒後まで）の値を持って摩擦抵抗力の値とした。
【０２６１】
先ず、図１５によれば、電圧Ｖｐｐが一定のとき、周波数を変化させたときには、周波数が大きくなると摩擦抵抗力が少なくなることが分かる。図１５において、周波数が０の時は、加振させない、つまり従来のクリーニングブレードの条件である。従来のブレードに比べ、圧電素子で加振させることによって摩擦抵抗力が下がることが分かる。
【０２６２】
次に、図１６は、各周波数ａ〜ｅで、電圧Ｖｐｐを変化させた時の結果を示している。同図において、周波数ａ〜ｅの大きさは、ａ＞ｂ＞ｃ＞ｄ＞ｅの関係に設定している。
【０２６３】
この図１６によれば、いずれの周波数でも電圧Ｖｐｐを上げることで摩擦抵抗力が下がることが分かる。周波数ａ、ｂではこれら２つの周波数の大きさが違うものの、電圧Ｖｐｐに対する変化はほとんど同じであることが分かる。
【０２６４】
以上、表面性試験機を使って、加振手段を設けたブレードとガラス面との摩擦抵抗力について評価を行った結果、ブレードに振動があることによって、摩擦抵抗力が下がることが判明した。
【０２６５】
後述するが、画像形成装置において、加振手段を設けたブレード部材を用いた場合、図１５及び図１６にクリーニングが良好な領域として図示する部分では、周波数が大きく、電圧Ｖｐｐが大きい領域ではクリーニング性が良好であることが分かっており、摩擦抵抗力を下げることでクリーニング性に効果があることが分分かる。従来ブレードと比較し、ブレード部材２１と像担持体１１との摩擦抵抗力が下がることによって、クリーニング性が向上したものと推測される。
【０２６６】
次に、上記本発明に係る画像形成装置におけるクリーニング性と、ブレードと像担持体との摩擦抵抗力との関係について説明する。
第２の発明に係る加振ブレードを備えたクリーニング装置（第１の発明の実施形態で説明したものと同様であることは前述したとおりである。）を搭載して、転写性、クリーニング性及び感光体、ブレード間の摩擦抵抗力を評価・測定した。
【０２６７】
帯電及び現像の条件は、次のとおりとし、評価時は一定とした。

【０２６８】
また、本発明に係る前記加振ブレードの加振手段を構成する圧電素子に対する駆動電圧の印加は、上述したように、パルス信号を発生させるための、ファンクションジェネレータと、これから発生した信号を増幅させる電源を通して行い、実際に圧電素子に印加される電圧を確認するため、増幅された電圧を分岐させ、これをオシロスコープによってモニタした。
【０２６９】
転写率について次のように評価を行った。
（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）で白い紙に転写させて、それをマクベス反射濃度計ＲＤ５１４型で測定した。
【０２７０】
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。
【０２７１】
【数２】

【０２７２】
（クリーニング評価）
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（住友スリーエム株式会社製）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以下のものを良好とし、それを超えるもの（濃度が高いもの）を不良とした。
【０２７３】
実際の出力は、感光体上に付着量が０．１ｍｇ/ｃｍ²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。
【０２７４】
次に、画像形成装置における摩擦抵抗力の見積もりは、次のようにして行った。
画像形成装置内に取り付けられるドラム状の像担持体１１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１１に当接するのは加振手段２３を設けたクリーニングブレード部材２１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、上述したように、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。ブレード部材２１と像担持体１１との摩擦抵抗力に相当する測定器としては、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。
【０２７５】
また、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。ただし、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。
【０２７６】
そこで、先ず、加振手段に対する駆動バイアスの電圧Ｖｐｐを２０Ｖ一定とし、駆動周波数を変化させたときの回転トルクの変化を図１７に示している。また、同図には、同時に、その各駆動バイアス条件でクリーニング動作を行わせたとき、つまり実際に残留トナーをクリーニングさせながら、５００００枚相当の出力を行った後の前述したクリーニング性の評価において、クリーニングが可能、良好であった領域も示している。
【０２７７】
この図１７から分かるように、回転トルクについても、駆動周波数を上げると回転トルクが下がり、前述した図１５に示したと同じような傾向を示している。クリーニング性との関係をみると、駆動周波数が高いところでクリーニングが可能、良好であることが分かる。加振がない場合は回転トルクも大きく、像担持体の回転に大きな負荷になっていることが予測され、かつクリーニング性も非常に悪い。
【０２７８】
従来の粉砕型トナーでは、ブレードに加振を与えなくてもクリーニングは可能であったが、高画質を狙うための球形に近いトナーを用いる場合には、前記第１の発明で説明したように加振の有無がクリーニング性に大きく影響を与える。
【０２７９】
次に、加振手段に対する駆動バイアスの駆動周波数を周波数ａ〜ｅと変化させ、各周波数での電圧Ｖｐｐを変えたときの回転トルクの変化を図１８に示している。また、同図には、同時に、その各駆動バイアス条件でクリーニング動作を行わせたとき、つまり実際に残留トナーをクリーニングさせながら、５００００枚相当の出力を行った後の前述したクリーニング性の評価において、クリーニングが可能、良好であった領域も示している。なお、周波数ａ〜ｅの大きさは、ａ＞ｂ＞ｃ＞ｄ＞ｅの関係に設定している。
【０２８０】
この図１８から分かるように、電圧Ｖｐｐを上げると回転トルクが下がり、前述した図１６と同じような傾向を示している。クリーニング性との関係を診ると、電圧Ｖｐｐが高いところでクリーニングが可能、良好であることが分かるが、低い周波数ｃ〜ｅではクリーニング性が悪い。電圧Ｖｐｐが０、つまり加振手段がない従来のブレードに比べ、電圧Ｖｐｐを上げて加振させることにより回転トルクを下げることが可能（ｃ、ｄ）であるが、クリーニング性の関係から、圧電素子への駆動バイアスはある程度の周波数の振動が必要であることが分かる。なお、周波数ｅでは、ブレード加振しても従来のブレードと回転トルクはほとんど変わらなかった。
【０２８１】
これらの駆動バイアスの条件を変化させた結果とクリーニング性との関係から、回転トルクを下げる、言い換えればブレードと像担持体との摩擦抵抗力を下げることによってクリーニング性が向上することが分かる。
【０２８２】
次に、画像形成装置の像担持体を回転させるモータとしてＤＣモータとし、このモータに対する駆動電流の電流値を検出測定した。この場合、摩擦抵抗力が低い、つまりモータへの負荷が小さい時には、ＤＣモータに流れる電流が低くなることが予測される。実際に、先の回転トルクメータの評価と同じように、ドラム状の像担持体を駆動させるモータをＤＣモータに変えて実験を行ない、加振手段である圧電素子に対する駆動信号の周波数を変化させた結果及び電圧Ｖｐｐを変化させたときの結果を図１９及び図２０に示している。
【０２８３】
駆動バイアスとモータの駆動電流の変化の傾向としては、これまでの回転トルクを見た結果と同じであるが、各周波数ａ〜ｅにおける電圧Ｖｐｐの変化は線形で変化していることが分かる。同じようにクリーニング性との関係をみると、モータの駆動電流が小さい場合にはクリーニング性が向上することが分かる。
【０２８４】
したがって、駆動電流を検出し、この検出結果に基づいて摩擦抵抗力を見積もる方法では、摩擦抵抗力を直接的に把握することはできないが、回転トルクメータのように機械的な装置を備えることなく、画像形成装置を構成することが可能となる。
【０２８５】
そして、駆動バイアスを変化させた結果とクリーニング性との関係から、ＤＣモータを駆動するための駆動電流を下げる、言い換えればブレードと像担持体との負荷つまり摩擦抵抗力を下げることによってクリーニング性が向上することが分かる。
【０２８６】
以上より、像担持体の回転トルク、あるいは、ＤＣモータの駆動電流の検出結果に基づいて、作像の条件（トナー消費量、環境条件、印刷枚数）から加振手段を構成する圧電素子をフィードバック制御して、ブレード部材と像担持体との摩擦抵抗力を変化させることによって、安定した良好なクリーニング性を得ることができる。
【０２８７】
クリーニング性の評価は、初期では判断が困難であり、ある程度の出力枚数後のクリーニング性の評価が実際のトナークリーニングでは必要となる（前述したしたように、評価では５００００枚の出力後のクリーニング性を評価し、これと加振条件とで比較を行っている。）。
【０２８８】
さらに、実際の画像形成装置を使用して作像を行わせる際に、像担持体の表面は、トナーのフィルミングや感光層の膜削れ等の変化が起きる（これは、摩擦抵抗力を下げた第２の発明でも少なからず起きていると容易に推測される。）。そのため、クリーニングに最適な条件、ここではブレードと像担持体との摩擦抵抗力が変化していると考えられる。
【０２８９】
そこで、加振手段による加振条件を何らかの手段で制御することが必要になるが、そのために圧電素子を使うことが最も有効であることは前述した通りである。圧電素子の駆動バイアスを変化させることで、摩擦抵抗力、回転トルク、ＤＣモータの駆動電流を下げることが可能になり、ある程度の画像の出力でこれらの条件が変化しても最適な条件でクリーニングを行うことが可能になる。
【０２９０】
ここで、加振条件変化の指標について説明すると、フィルミングはトナーがブレードにより像担持体表面で引き伸ばされることにより起こる不具合である。トナーがフィルミングすることにより、ブレードと像担持体との間の摩擦抵抗力はトナーの種類によって下がることや上がることがある。いずれにしても、正常なクリーニングを確保するためには、トナーをクリーニングするに必要な最低限の摩擦抵抗力を維持することが必要である。
【０２９１】
トナーのフィルミングはトナーの消費量や出力される画像面積比率に対し、完全な線形性はもたないまでも、消費量が多い、画像面積比率が高い場合にフィルミングは助長されるという傾向がある。この理由としては、像担持体と接触するトナー量が多くなればそれだけブレードでフィルミングを引き起こしやすいからと推測される。
【０２９２】
そこで、画像データに基づいて画像面積比率を求めて、この画像面積比率に基づいて、ブレードの加振条件を変化させることで、摩擦抵抗力、あるいは回転トルク、ＤＣモータ使用時の駆動電流を制御する上で最適なクリーニング条件にすることが可能である。また、環境条件が変化した場合、ブレード部の環境に対する変形もクリーニングブレード当接条件を変化させるため、摩擦抵抗力、回転トルク、ＤＣモータ駆動電流も変化することが予測されるため、環境変化に応じて、これらの値を検出し、検出結果に応じて適切な加振条件に設定することによって最適なクリーニングを行うこともできる。
【０２９３】
次に、前記第１の発明及び第２の発明における、加振ブレード２０のブレード部材２１の像担持体１１に対する押し付け量及び当接角について図２１を参照して説明する。なお、同図はブレード部材２１と像担持体１１の当接状態を示す要部拡大説明図である。
先ず、ブレード部材２１は像担持体１１の回転方向（矢示Ａ方向）に対して、カウンタ方向で当接している。すなわち、ブレード部材２１と像担持体１１とが当接する角度θが開く方向へ像担持体１１が移動する設定としている。
【０２９４】
これにより、ブレード部材２１のカット面２１ａのめくれを無くし、くさび形状が形成されたとしても非常に小い形状を維持することが可能となり、ニップ部へのトナーの入り込みを防止することができる。
【０２９５】
そして、ブレード部材２１は、上述した押し付け力によってニップ部先端において像担持体１１に押し付けられるが、このときの像担持体１１表面からブレード部材２１の高さ方向で押付け量をｄとしている。つまり、ブレード部材２１の先端の接触位置からさらに押し付け量ｄの高さだけ像担持体１１の方向へ押し付けた状態を初期設定とする。ここで、初期設定とは、加振しない状態でのブレード押し付け量であり、前記単板圧電素子を加振手段２３に用いた加振ブレード２０では、押し付け量ｄは弾性のブレードニップ部の変形と圧電素子を含む振動部材２２の撓み変形の量に相当する。
【０２９６】
この押し付け量ｄの値は、ブレード部材２１の厚さ、硬度にもよるが、厚さ１００〜３００μｍ、硬度がＪＩＳＡ７５〜１００°の場合、押し付け量ｄは、１０〜１００μｍの範囲内とすることが好ましい。ブレード部材２１の厚さが薄く、硬い方向の場合押し付け量ｄは小さく、厚く、硬度が小さい場合押し付け量ｄは大きい値とする。
【０２９７】
また、ブレード部材２１の像担持体１１に対する当接角度θは、０〜５０°の範囲内とすることで、ブレード部材２１のカット面２１ａのめくれを無くし、くさび形状が形成されたとしても非常に小い形状を維持することが可能となり、ニップ部へのトナーの入り込みを防止することができ、クリーニング性能が得られる。
【０２９８】
この当接角度θが０〜１０°のときは、振動部材２２に貼り付けているブレード部材２１の長さ寸法Ｌ（図２参照）は２〜５ｍｍと短くして実際に像担持体１１との接触する長さを短くした場合に好ましい構成であり、ブレード部材２１の長さ寸法Ｌが５ｍｍ以上と長い場合は１０〜５０°の範囲内で傾斜させてブレードエッジ部２１ｂ（図４参照）が接触する構成とすることが好ましい。
【０２９９】
次に、振動板部材２２に対するブレード部材２１の突き出し量について上述した図２１及び図２２を参照して説明する。
まず、図２１に示す例では、ブレード部材２１の剛性より振動部材２２の剛性が高い構成とし、且つ、ブレード部材２１と振動部材２２の先端突き出し量の関係を両者ほぼ同じ（又はブレード部材２１の先端を振動部材２２より短く、つまり振動部材２２先端より後退した）構成としている。
【０３００】
このような構成とすることで、加振手段２３による振動部材２２の振動の伝搬がニップ部で減衰することが抑えられて、トナーのクリーニングに直接作用するブレードニップ部にほぼ同レベルで伝えることができ、より効率の良いクリーニングが可能となる。
【０３０１】
また、図２２に示す他の例では、前同様に、ブレード部材２１の剛性より振動部材２２の剛性が高い構成とするが、ブレード部材２１の先端を振動部材２２の先端より突き出し量ｈだけ突き出した関係の構成としている。ただし、微小量の高周波数の振動はゴム弾性部材のブレードに吸収されやすい。実験の結果、ブレードの硬さがＪＩＳＡ硬度で８０〜１００°の範囲内のものを使用し、ニップ部変位量の減衰が７０％以下にするためには、振動部材２２に対するブレード２１の先端の突き出し量ｈをブレード厚さの２倍以下の設定にすれば良いことが判明した。
【０３０２】
これによって、加振手段２３による振動部材２２の振動の伝搬がニップ部で減衰することが抑えられて、トナーのクリーニングに直接作用するブレードニップ部にほぼ同レベルで伝えることができ、より効率の良いクリーニングが可能となるとともに、加振手段２３の駆動条件を圧電素子の発熱が問題にならない範囲の電圧、周波数設定が可能となり、球形、小径トナーのクリーニングが可能となる。
【０３０３】
次に、クリーニング装置１６の加振ブレード２０の第４実施形態について図２３及び図２４を参照して説明する。
この実施形態では、加振手段２３として前記実施形態と同様に板状圧電素子を用い、振動部材２２には圧電素子を接合する領域に対応した部分を薄くした薄肉部２２ｂを形成して、その部分だけが弾性変形しやすい構造としている。なお、ブレード部材２１はウレタンブレード部材であり、振動部材２２は先端領域にブレード部材２１が接合され、像担持体１１へのブレード部材２１の当接角度θ、食い込み量（押し付け量）ｄを決める構成としていることは前記図２の構成と同様である。
【０３０４】
これによって、振動部材２２のブレード部材２１を取り付ける先端領域の剛性を高くすることができ、固有振動数を高く設定できるため、ブレード部材２１の幅方向において振動部材２２の先端部を高周波数領域まで均一に振動させることができるようになり、クリーニングムラのない高性能クリーニングが可能となる。そして、圧電素子を接合した領域に対応した部分のみ振動部材２２を薄くしているので、加振ブレード２０全体の固有振動数を高く維持でき、高い周波数までの加振が可能となる。
【０３０５】
また、振動部材２２は、複数の加振手段２３の間には幅方向に複数箇所の抜き領域（肉抜き部）２２ｄを設けている。これにより、圧電素子（加振手段２３）による振動部材２２の先端方向への撓み変形の効率がより向上し、より効率的にブレード部材２１を振動させることができる。
【０３０６】
ここで、この実施形態の加振ブレード２０（クリーニングブレード）について、実際のニップ部の振動変位量を測定した結果について図２５、図２６を参照して説明する。
【０３０７】
図２５に示すブレードニップ面変位量の測定条件としては、ブレード部材２１の幅をＡ３サイズ横幅とし、像担持体１１へのニップ部押付け量ｄ：５０μｍ、複数の各圧電素子（加振手段２３）へは共通の駆動信号Ｐｖを印加し、駆動信号Ｐｖは、電圧２２０Ｖ、周波数１０〜４０ｋＨｚの４段階とした。使用した圧電素子は、厚さ０．３ｍｍ、縦横寸法７×１０ｍｍとした。測定に使用した振動変位計は、グラフテック社製ＡＴ００２１レーザドップラ振動計、ビーム径Φ１２μｍによる。
【０３０８】
この結果から、Ａ３幅対応のクリーニングブレードで、幅方向においてほぼ均一な変位が得られることが分かる。
【０３０９】
また、図２６は上記と同様に測定した結果であるが、圧電素子に印加する駆動信号Ｐｖの駆動電圧を８０Ｖにしている。この場合も、前記より変位量は低いが比較的像担持体の線速が遅い場合においては摩擦力を低下させるには十分な性能である。
【０３１０】
次に、クリーニング装置１６の加振ブレード２０の第５実施形態について図２７を参照して説明する。
この実施形態では、加振手段２３として板状圧電素子を用い、２枚の圧電素子（加振手段２３）を振動部材２２の両面に設けている。２つの圧電素子（加振手段２３）は電圧を印加することによって、一方は面方向に伸び、他方は面方向に縮む方向の変形を与えるように設定している。
【０３１１】
これにより、振動部材２２を２倍の力で撓ませることができ、また、全体の剛性が高くなるので、固有振動数を高くできる。
【０３１２】
次に、クリーニング装置１６の加振ブレード２０の第６実施形態について図２８を参照して説明する。
この実施形態では、振動部材３２を厚くして剛性を高くし、積層型圧電素子を用いた加振手段３３を挟み込むようなコ字型の凹部３２ａを形成し、この凹部３２ａに前記第４実施形態と同様なｄ３３方向の変位を利用する積層型圧電素子を配置している。
【０３１３】
そして、加振手段３３によって振動部材３２の先端部が効率良く振動するように、振動溝３２ｃを設けて一部分３２ｂが薄くなるように形成している。また、ブレード部材２１は、振動部材３２からの振動が伝わりやすいように薄層化している。
【０３１４】
これにより、振動部材３２のブレード部材２１を取り付ける部分の剛性を高めることができ、より効率的にブレード部材２１に振動を伝搬することができるようになる。
【０３１５】
次に、第１の発明あるいは第２の発明に係るクリーニング装置を含む第１の発明あるいは第２の発明に係るプロセスカ−トリッジについて図２９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。
【０３１６】
このプロセスカートリッジ７０は、像担持体７１、帯電手段７２、現像手段７４、第１の発明又は第２の発明に係るクリーニング装置７６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。
【０３１７】
クリ−ニング装置７６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。
【０３１８】
次に、第１の発明或いは第２の発明に係るプロセスカートリッジを用いた第１の発明或いは第２の発明に係るカラー画像形成装置について図３０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）８１に沿って、各色の上述したプロセスカ−トリッジ７０を並置したタンデム方式のカラー画像形成装置である。
【０３１９】
プロセスカ−トリッジ７０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７０で現像された像担持体７１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８１に順次転写される。
【０３２０】
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８１上に多重に転写され、転写手段８２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７０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。
【０３２１】
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。
【０３２２】
そこで、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７０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。
【０３２３】
さらに、プロセスカートリッジ７０を第１の発明のプロセスカートリッジとすることで、球形トナーを用いてもクリーニング不良の発生がなく、高画質画像を形成することができる。
【０３２４】
また、第２の発明に係るプロセスカートリッジとすることで、カラートナーは各種の色材の材料によって特性が変化することがあるが、この場合でも摩擦抵抗力（像担持体の回転トルク、ＤＣモータの駆動電流）を画像形成時で最適化することができ、クリーニング性を維持し、耐久性を向上させる画像形成装置を得ることができる。
【０３２５】
なお、上記実施形態においては、球形トナーで説明した、小径トナーであっても同様であり、第１の発明については、球形トナー、小径トナーのいずれも含まれ、第２の発明については、更に不定形トナーも含まれるものである。
【０３２６】
【発明の効果】
以上説明したように、本発明に係る画像形成装置によれば、円形度が０．９６〜１．００のトナーを使用しても、クリーニング不良を生じることなく残留トナーをクリーニングすることができるので、高画質画像を形成することができる。
【０３２８】
本発明に係るプロセスカートリッジによれば、高画質画像を形成することが可能になる。
【０３２９】
本発明に係る他の画像形成装置によれば、本発明に係るプロセスカートリッジを複数備えているので、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】 本発明に係る画像形成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加振ブレードの第１実施形態の説明に供する要部拡大説明図
【図４】 図３の要部拡大説明図
【図５】 同加振ブレードの正面説明図
【図６】 同加振ブレードを先端側から見た説明図
【図７】 同クリーニング装置に対する駆動系の一例を説明する説明図
【図８】 同クリーニング装置の加振ブレードの第２実施形態の説明に供する説明図
【図９】 同加振ブレードの像担持体幅方向の説明図
【図１０】 同クリーニング装置の加振ブレードの第３実施形態の説明に供する説明図
【図１１】 同加振ブレードを先端側から見た説明図
【図１２】 トナーの円形度の説明に供する説明図
【図１３】 ブレード部材と像担持体との摩擦抵抗力に関する測定実験の説明に供する模式図
【図１４】 同測定結果の一例を示す説明図
【図１５】 加振ブレードに対する駆動信号の周波数と摩擦抵抗力の関係及びクリーニング性の説明に供する説明図
【図１６】 加振ブレードに対する駆動信号の周波数、駆動電圧と摩擦抵抗力の関係及びクリーニング性の説明に供する説明図
【図１７】 加振ブレードに対する駆動信号の周波数と像担持体の回転トルクの関係及びクリーニング性の説明に供する説明図
【図１８】 加振ブレードに対する駆動信号の周波数、駆動電圧と像担持体の回転トルクの関係及びクリーニング性の説明に供する説明図
【図１９】 加振ブレードに対する駆動信号の周波数と像担持体の駆動モータの駆動電流の関係及びクリーニング性の説明に供する説明図
【図２０】 加振ブレードに対する駆動信号の周波数、駆動電圧と像担持体の駆動モータの駆動電流の関係及びクリーニング性の説明に供する説明図
【図２１】 ブレード部材の当接角度及び押し付け量の説明に供する説明図
【図２２】 振動部材とブレード部材の突き出し量の説明に供する説明図
【図２３】 同クリーニング装置の加振ブレードの第４実施形態の説明に供する説明図
【図２４】 同クリーニング装置の像担持体幅方向の説明図
【図２５】 同クリーニング装置におけるブレードニップ部の変位量の測定結果を説明する説明図
【図２６】 同クリーニング装置におけるブレードニップ部の変位量の他の測定結果を説明する説明図
【図２７】 同クリーニング装置の加振ブレードの第５実施形態の説明に供する説明図
【図２８】 同クリーニング装置の加振ブレードの第６実施形態の説明に供する説明図
【図２９】 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３０】 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３１】 従来のクリーニングブレードの説明に供する説明図
【図３２】 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３３】 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３４】 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３５】 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３６】 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…加振ブレード、２１…ブレード部材、２２…振動部材、２３…加振部材、７０…プロセスカートリッジ。[0001]
The present invention Is a picture The present invention relates to an image forming apparatus and a process cartridge.
[0002]
[Prior art]
[Patent Document 1]
JP 2001-188452 A
[Patent Document 2]
JP 2000-267536 A
[Patent Document 3]
JP-A-60-131547
[Patent Document 4]
Japanese Patent Laid-Open No. 6-148941
[Patent Document 5]
JP-A-8-254873
[0003]
The In electrophotographic image forming apparatuses such as printers, facsimiles, and copying machines, the electrostatic latent image formed by charging and exposing the surface of the image carrier is developed with colored toner to form a toner image as a visible image. The toner image is transferred to a transfer medium such as transfer paper, and fixed with a heat roll or the like to form an image. On the other hand, since untransferred toner generally remains on the surface of the image carrier after the toner image has been transferred, it is necessary to remove this residual toner by a cleaning unit prior to the next image forming process. In general, other foreign matters attached to the surface of the image carrier are also removed together with the residual toner by the cleaning means.
[0004]
As the cleaning means for removing the residual toner after the transfer, various types such as those using a fur brush, a magnetic brush, etc., and those using a cleaning blade made of an elastic material are used. A means for scraping off the toner by rubbing the image carrier with a blade is generally used because it is inexpensive and has high performance stability. For the elastic body used as a material for the cleaning blade, polyurethane rubber having excellent wear resistance is often used.
[0005]
Also, In recent years, high image quality has progressed especially in full-color image forming apparatuses, and as one direction for achieving high image quality, toner particle size reduction and spheroidization have been promoted. By reducing the particle size, it is possible to improve the reproducibility of the dots of the toner image formed on the surface of the image carrier, and it is possible to improve the developability and transferability by making it spherical.
[0006]
As a method for spheroidizing the toner for improving the image quality, a method for producing a polymerized toner with a polymerization reaction which is a chemical reaction has been adopted instead of the conventional pulverization method. There are several types of production methods for this polymerized toner, even if they are in the same polymerization reaction category, but there is no need for a pulverization classification process as seen with pulverized toner, or this process can be greatly reduced. Has the advantage.
[0007]
However, when a small-diameter toner or a spherical toner is used, a conventional cleaning device using a cleaning blade has a problem in that it is difficult to completely remove the transfer residual toner on the surface of the image carrier and a cleaning failure occurs. .
[0008]
It is clear that this cleaning performance defect and poor cleaning occur even when the conventional pulverized toner is subjected to mechanical processing (re-pulverization) or heat treatment to reduce the particle size or spheroidize, Regardless of the toner manufacturing method, when the toner has a small particle size or a spherical shape, there is a problem that good cleaning performance cannot be obtained by blade cleaning.
[0009]
The toner that has caused such a cleaning defect becomes an image quality defect when the next output image is formed. In particular, when the charging device is a roller-type contact charger, the toner cannot be removed by the cleaning blade (not cleaned). It has a great influence because toner may accumulate on the roll-shaped charger and cause charging failure. In particular, the toner whose circularity (details of circularity will be described later) of the toner is close to 1, that is, a toner close to a spherical shape (true sphere), the cleaning property is remarkably deteriorated. Even a toner with a circularity of 0.95 or less has a shape distribution, so that a substantially spherical toner exists, and the cleaning properties tend to deteriorate over time.
[0010]
In addition, this cleaning property tends to deteriorate as the particle size of the toner used for development decreases. Furthermore, the image forming apparatus is used in a temperature range of about 10 ° C. to 30 ° C., but the deterioration of the cleaning property is noticeable particularly at low temperatures.
[0011]
Causes of the occurrence of poor cleaning when using small toner or spherical toner.
In general, there are reasons as described in [Patent Document 1], but it is considered to be due to the following reasons.
[0012]
That is, in the cleaning method using the cleaning blade, the toner is scraped off by rubbing the image carrier with the rubber blade as described above, and therefore the edge of the rubber blade is caused by the frictional resistance between the image carrier and the rubber blade. The tip is deformed to form a minute wedge-shaped space between the two. In this space, the smaller the diameter of the toner, the easier it is to enter the edge tip, and the toner that has entered the edge tip is not easily replaced, and forms a non-flow region.
[0013]
In addition, since the spherical toner is more easily packed closer than the irregular toner, the spherical toner is easily compacted in a minute space near the contact point between the edge of the cleaning blade and the image carrier. In the state where the friction resistance between the toner in the non-flow region and the image carrier is relatively small and the toner is sliding with respect to the image carrier, cleaning failure does not occur, but the external additive by rubbing with the image carrier When the frictional force between the toner and the image carrier increases due to the separation of the toner, the rolling friction of the spherical toner is smaller than that of the conventional pulverized amorphous toner, so that the roller starts to roll between the cleaning blade and the image carrier and slips through. It is possible. This point will be described later because it has been elucidated as a result of intensive studies by the present inventors.
[0014]
Therefore, in the above [Patent Document 1], in order to efficiently remove the residual toner on the image carrier of the image forming apparatus using the spherical toner produced by the polymerization method, the residual toner on the surface of the photosensitive member after transfer is removed. A cleaning device is disclosed that includes a cleaning blade that scrapes off and a cleaning brush that is disposed upstream of the cleaning blade in the direction of movement of the photosensitive member and that pulverizes residual toner and generates fine toner on the photosensitive member.
[0015]
In addition, in Patent Document 2, in order to improve the cleaning performance for the spherical toner of the image carrier cleaning blade of the image forming apparatus, the surface carrying the toner image formed by the spherical toner has the transfer region and the cleaning region. A toner image carrier that rotates and moves through, a transfer device that transfers the toner image on the surface of the toner image carrier that passes through the transfer region to a transfer material, and a toner image carrier surface that passes through the cleaning region. A cleaning blade made of an elastic member having a blade edge for removing residual toner on the surface of the toner image carrier, a powder lubricant applied to the blade edge, and an amorphous toner having an average particle size smaller than that of the spherical toner And an image forming apparatus comprising a toner image carrier cleaner having a mixed powder material That.
[0016]
Examples of using a mixture of spherical toner and irregular toner in this way include those described in [Patent Document 3], [Patent Document 4], and [Patent Document 5].
[0017]
Mentioned above In the cleaning device described in Patent Document 1, since the cleaning brush that pulverizes the residual toner and generates fine toner on the photosensitive member is provided, the size of the device is increased, and the resin toner is pulverized. This is very difficult, and even if it can be pulverized, the surface of the image carrier is damaged, and the image quality is lowered.
[0018]
Further, in the cleaning device described in [Patent Document 2], since the mixed powder material with the amorphous toner having an average particle size smaller than that of the spherical toner is used, the image quality is improved by using the spherical toner. This results in a reduction in the image quality.
[0019]
Therefore, the present inventors first studied and elucidated the cause of the occurrence of poor cleaning with a counter-type cleaning blade when spherical toner was used.
[0020]
That is, as shown in FIG. 31, in the cleaning device using a typical counter type cleaning blade, the tip of the cleaning blade 101 held by the metal holder 100 is moved toward the image carrier 111. The abdominal surface 101c of the cleaning blade 101 and the surface of the image carrier 111 are brought into contact with each other at an angle θ so as to be a counter with respect to the rotation direction A, and the tip (free end) of the cleaning blade 101 is pressed with a pressing amount d. Residual toner on the image carrier 111 is cleaned by pressing the image carrier 111.
[0021]
Thus, 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. 32, the cleaning blade 101 is an elastic member. Due to the movement in the direction A, the edge portion 101b of the cut surface 101a of the blade 101 is pulled in the direction indicated by the arrow 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. It becomes a state. By turning 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.
[0022]
In this case, when the toner to be used is a pulverized toner, as shown in FIG. 33, the pulverized toner Ta is distorted in shape, so that a wedge-shaped nip formed by the cleaning blade 101 and the image carrier 111 is formed. As a result, the edge portion of the toner Ta is caught. At this time, a repulsive force for returning the deformed portion of the tip surface of the blade 101 to its original state works, and so-called stick-slip motion occurs.
[0023]
This stick-slip motion will be described with reference to FIG. When the blade nip is in a stick state (fixed) on the moving image carrier surface, the blade nip is forcibly extended in the rotational direction of the image carrier 111 as indicated by a broken line in FIG. When the blade nip is stretched to a certain position, the repulsive force of the blade increases, and the blade nip slides with respect to the image carrier surface when the static frictional force and the repulsive force are balanced. In a state where slip occurs between the blade nip and the image carrier, the dynamic friction coefficient is smaller than the static friction coefficient, so that the blade nip returns to the original direction (direction indicated by the solid line) while sliding on the surface of the image carrier. The toner Ta staying at the wedge-shaped nip portion is returned in the direction opposite to the traveling direction of the image carrier 111 by the return force of the stick-slip repetitive motion (the range is indicated by SP). Clean with force.
[0024]
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.
[0025]
When the spherical toner Tb is used, since the toner does not have a distorted portion like the pulverized toner Ta and does not get caught at the tip of the blade 101, the toner enters the wedge-shaped nip, and the cleaning blade 101 and the image carrier 111. The spherical toner Tb in a state of being sandwiched between the toners receives a moment of rotation using the contact portion as a drive source due to a frictional force with the image carrier 111. Accordingly, 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 slips between the blade 101 and the image carrier 111. The cleaning becomes defective.
[0026]
At this time, once the spherical toner Tb slips through, the spherical toner Tb functions like a lubricant between the cleaning blade 101 and the image carrier 111 as shown in FIG. The frictional force of the carrier 111 is reduced, and the tip (cut) surface of the blade 101 is released from turning (returning the blade 101 to its initial shape). Therefore, the stick-slip motion described above, which is a basic cleaning function by the blade 101, does not occur, and a phenomenon in which toner cleaning failure occurs continuously.
[0027]
Although the mechanism of occurrence of poor cleaning of spherical toner has been described above, small-diameter toner also easily enters the wedge-shaped nip portion shown in FIG. It was confirmed that the smaller the diameter of the toner, the less the catch at the edge portion, and thus the slip-through is likely to occur.
[0028]
As a result of further earnest research based on the occurrence of defective cleaning of spherical and small-diameter toners as clarified as described above, the present inventors have cleaned spherical and small-diameter toners by a new mechanism different from conventional cleaning mechanisms. I found out that I can do it.
[0029]
In addition, In the blade cleaning method (cleaning method using a cleaning blade) as described above, the toner cleaning property is improved, in other words, the rubbing ability is increased, so that the frictional resistance between the blade and the image carrier tends to be increased. It is generally known that there are.
[0030]
In particular, when there is no residual toner after transfer on the image carrier, the frictional resistance between the blade (edge) portion and the image carrier becomes very high, and in severe cases, the blade is pulled to the image carrier. The phenomenon of so-called “warping back” occurs, and the cleaning function may not be brought out.
[0031]
In the cleaning method using a blade, as described above, the image carrier is rubbed and scraped off with the rubber blade, and the edge of the rubber blade is deformed by the frictional resistance between the image carrier and the rubber blade. However, a minute wedge-shaped space is formed between them. Since it is important for cleaning to create this wedge-shaped region, the formation of the blade edge portion greatly affects the cleaning performance.
[0032]
However, if the frictional resistance between the blade edge portion and the image carrier is too large, the edge portion necessary for cleaning may be lost in addition to the above-mentioned “warping back”. Therefore, it is preferable to maintain the edge portion while ensuring and maintaining the minimum frictional resistance necessary for toner cleaning as much as possible from the viewpoint of durability. However, the conventional cleaning means using the cleaning blade has a problem that it is impossible to ensure and maintain the minimum frictional resistance necessary for cleaning the toner.
[0033]
Furthermore, it has been clarified by the inventor's earnest research that the trouble caused by the increased frictional resistance between the blade edge portion and the image carrier occurs not only on the blade edge chip but also on the image carrier. .
[0034]
As an example, the toner is stretched by a blade on the surface of the image carrier, and a filming that forms a toner layer on the film on the image carrier and a film scraping of the photosensitive layer constituting the image carrier are caused. That's what it means. Since filming is formed on the photosensitive layer, it hinders accurate image formation as much as possible, and film scraping reduces the durability as an image carrier, and neither of them causes such a phenomenon as much as possible. It is necessary to do so. In some cases, film scraping proceeds while filming occurs, and as a result, only the phenomenon of film scraping may appear to occur.
[0035]
It has been found that these are phenomena that occur due to the large frictional resistance between the blade and the image carrier in the image forming apparatus using the cleaning blade.
[0036]
The present invention has been made in view of the above problems. , An object of the present invention is to provide an image forming apparatus and a process cartridge with improved cleaning properties, and an image forming apparatus provided with the process cartridge.
[0038]
[Means for Solving the Problems]
In order to solve the above problems, an image forming apparatus according to the present invention forms a latent image on the surface of an image carrier, develops the latent image with toner, forms a toner image, and transfers the toner image to a transfer target. In an image forming apparatus that removes toner remaining on the surface of the image carrier after being transferred to the body with a cleaning unit, the cleaning unit has a blade member that comes into contact with the surface of the image carrier and one end fixed, and is free A plate-like vibration member having a blade member attached to one surface of the other end serving as an end, and attached to a surface opposite to the blade member attachment surface of the other end of the vibration member, Perpendicular to the blade member mounting surface And a vibration means that vibrates the other end of the vibration member in the direction, and is configured to clean the toner by vibration of a portion of the blade member in contact with the image carrier.
[0039]
Here, the toner is preferably a toner prepared by a polymerization method. Further, the surface of the blade member including at least the contact portion with the image carrier is formed of a material having a low affinity with the toner material, or an external additive added to the outside of the toner is used for the blade member. It is preferable that the affinity with the member forming the surface is small. Furthermore, it is preferable that the vibration amount at the nip portion of the blade member is smaller than the average particle diameter of the toner.
[0040]
In addition, it is preferable to be able to control the amount of displacement due to vibration in the nip portion of the blade member. In this case, it is preferable to include means for electrically controlling the amount of displacement of the blade member. Furthermore, the vibration means is preferably a piezoelectric element, and in this case, it is preferable that a means for applying an alternating voltage to the piezoelectric element is provided.
[0041]
Furthermore, it is preferable to provide means for differentiating the displacement amount due to the vibration of the blade member between image formation and non-image formation. In addition, it is preferable to include means for changing the amount of displacement caused by the vibration of the blade member based on at least one of the number of times of toner adhesion image formation on the image carrier, environmental conditions, and the amount of toner replenishment.
[0048]
The process cartridge according to the present invention is a process cartridge including at least an image carrier and a cleaning unit. The cleaning unit has a blade member for contacting the surface of the image carrier and one end fixed to be a free end. A plate-like vibration member having a blade member attached to one surface of the other end portion, and attached to the surface opposite to the blade member attachment surface of the other end portion of the vibration member, Perpendicular to the blade member mounting surface And a vibration means that vibrates the other end portion of the vibration member in the direction, and is configured to clean the toner by vibration of a portion of the blade member that contacts the image carrier.
[0049]
According to the present invention Another image forming apparatus includes a plurality of process cartridges according to the present invention.
[0058]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, a novel cleaning mechanism for small-diameter, spherical toner employed in the first invention will be described with reference to FIG.
As shown in FIG. 1, the cleaning device according to the first aspect of the present invention applies vibration from the blade member 1 to the wedge-shaped toner T formed by the blade member 1 and the image carrier 11, so that the toner T Rotation due to frictional force is prevented, and defective cleaning of spherical toner is prevented.
[0059]
These vibration operations can prevent the spherical toner and small-diameter toner from entering the blade nip portion by vibrating the nip portion of the blade member 1 so as to have a shape and movement different from those of the conventional cleaning blade. It is possible to eliminate defective cleaning of spherical toner and small-diameter toner.
[0060]
That is, FIG. 1 shows a state in which the blade member 1 is in a vibrating state, and the vibration is transmitted to the spherical toner T by the vibration, and the toner T is vibrated actively (indicated by a white arrow in the figure). FIG. This shows the result of observation by a high-speed video camera through a high-magnification microscope. In the figure, 1a is a cut surface, 1b is an edge portion 1b, and 1c is an abdominal surface of the blade member 1 (a surface facing the surface of the image carrier 11).
[0061]
At this time, it is found that the spherical toner T in the vicinity of the front end cut surface 1a of the blade member 1 and the image carrier 11 vibrates over a range of several toners (range B in the drawing). did.
[0062]
In such a state, the vibrating toner group (B portion toner) in the vicinity of the nip portion acts as a barrier (vibrating toner wall), and the subsequent toner T on the image carrier 11 (C portion in the figure). Intrusion of toner) is prevented, and even a spherical toner close to a true sphere is in a state where no cleaning failure occurs.
[0063]
At this time, the vibration of the blade member 1 and the transmission of vibration from the blade member 1 to the image carrier 11 also reduce the frictional force between the blade member 1 and the image carrier 2. It has been found that there is a condition that eliminates the phenomenon that the cut surface 1a of the blade member 1 that has occurred is not turned up. The "turning of the cut surface" here is usually a blade member that is cut in the thickness direction of a molded elastic member and finished with a sharp shape with no burrs or chips on the edge. This means that the surface is deformed with the movement of the image carrier and comes into contact with the surface of the image carrier (the state shown in FIG. 23 described above).
[0064]
By eliminating the occurrence of turning of the cut surface of the blade member 1, stress from the blade member 1 to the image carrier 11 is also reduced, and as a result, the durability of the blade member 1 and the image carrier 11 is remarkably increased. It has also been found that a very large effect of improvement can be obtained.
[0065]
Accordingly, an image forming apparatus according to the first invention, which includes the cleaning device according to the first invention and to which the cleaning method according to the first invention is applied, will be described below with reference to FIG. FIG. 2 is a schematic configuration diagram of the image forming apparatus.
[0066]
The 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 unit 16, and a charge eliminating unit 17 are disposed 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 arranged.
[0067]
Here, the charging unit 12 is arranged on the surface of the image carrier 11 at a predetermined distance so as to be in contact with or non-contact with the image carrier 11, and applying a bias to the charging unit 12 causes the image carrier 11 to have a predetermined polarity. Charge to a predetermined potential.
[0068]
The exposure 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.
[0069]
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 toner and carrier as a developer. As another developing method, a one-component developing method that does not use a carrier may be used.
[0070]
A voltage is applied to the developer carrier 14A from a developing bias power source. 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, development is performed by attaching a charged toner to the electrostatic latent image in the developing region.
[0071]
The transfer unit 15 contacts the surface of the image carrier 11 with a predetermined pressing force at the time of transfer, and a voltage is applied, whereby the surface of the image carrier 11 is transferred at the transfer nip portion between the image carrier 11 and the transfer unit 15. The toner image is transferred onto the transfer material 18. In this image forming apparatus, transfer is performed using a transfer roller, but transfer means such as a corotron and a transfer belt may be used.
[0072]
The cleaning device 16 is a cleaning device according to the first aspect of the invention, and includes a blade member 21, a vibration member 22, and a vibration means 23 (a portion constituted by these members is referred to as a “vibration blade 20”). And the necessary vibration is applied to the blade member 21 as described above to remove the residual toner on the surface of the image carrier 11. The toner cleaned from the image carrier 11 by the cleaning device 16 is stored as waste toner in a waste toner bottle (not shown) by a toner conveying member and collected by a service person or transported to a developing device as recycled toner. Used for development.
[0073]
The neutralization unit 17 neutralizes the residual charge of the image carrier 11 from which the residual toner has been removed by the cleaning device 16, and uses a static neutralization device using an LED or the like.
[0074]
Further, the image forming apparatus is provided with a density sensor 19 for optically detecting the toner adhesion amount after the development process of the image carrier 11 is completed. The detection signal from the density sensor 19 is taken into a main control unit including a CPU that controls the entire image forming apparatus, and is converted from an optical reflectance into a toner adhesion amount.
[0075]
As the operation timing, the operation is determined to output in advance a set patch (a pattern of 1 cm × 1 cm square) immediately below the density sensor 19 at the time of non-image formation. In the image forming process, the development conditions are controlled to be the best. The size of the patch is very large as the amount of toner consumed on the entire surface of the image carrier 11, and is preferably as small as possible with a size necessary for detection by the density sensor 19.
[0076]
In addition, when the image carrier 11 is small, a density sensor composed of an optical sensor may not be arranged. In this case, it is possible to estimate the amount of toner consumed by passing a part of the developer through the cylinder and arranging a sensor for detecting a change in magnetic permeability in this passage. The detection signal of this sensor can be taken into the main control unit and converted into toner consumption.
[0077]
Further, when no sensor is arranged or when there is no problem even if the detection accuracy is lowered, for example, the toner consumption can be estimated by counting the number of output sheets (number of times of image formation) without providing any sensor. .
[0078]
Although not shown, since the developer changes according to environmental conditions, a temperature / humidity sensor for detecting the environmental conditions is provided. The output of the temperature / humidity sensor is taken into the main control unit described above, and the developer agitation condition is changed or the development bias is changed based on the environmental conditions.
[0079]
Based on the detection results of these various sensors, the vibration means 23 of the cleaning device 16 is feedback controlled to change the vibration amount of the blade member 21 and the like. As a result, the blade member 21 deteriorates at the tip depending on the amount of toner (image area) input thereto and the degree of rubbing (number of output sheets). Therefore, the optimum cleaning conditions can be set according to this state. it can. Also, the optimum cleaning condition can be set for the change in the mechanical contact condition of the blade member 21 due to the environmental condition.
[0080]
Next, details of the configuration of the cleaning device 16 according to the first embodiment will be described with reference to FIGS. 3 to 6. 3 is an enlarged explanatory view of the main part of the vibration blade of the cleaning device, FIG. 4 is an enlarged explanatory view of the main part of FIG. 3, FIG. 5 is an explanatory front view of the vibration blade, and FIG. It is explanatory drawing which looked at from the front end side.
[0081]
As described above, the vibration blade 20 of the cleaning device 16 includes the blade member 21, the vibration member 22 attached with the blade member 21, and the vibration means 23 attached to the vibration member 22. .
[0082]
The blade member 21 is an elastic body made of, for example, polyurethane rubber and has a thickness in the range of 50 to 1500 μm, preferably in the range of 100 to 500 μm. If the thickness is too thin, it becomes difficult to ensure the amount of pressing of the blade member 21 against the image carrier 11 due to the undulation of the surface of the image carrier 11 and the blade member 21 itself. If the thickness is too thick, the vibration from the vibration member 22 is absorbed, and the vibration to the tip of the blade member 21 is not sufficiently transmitted, so that the toner cleaning property is deteriorated. When the blade member 21 is thick, vibration transmission efficiency can be improved by using a hard member having a JIS hardness in the range of 85 to 100 ° as the material of the blade member 21.
[0083]
Here, depending on the manufacturing method of the thin urethane blade, a structure in which one member or two or more members are interposed between the blade member 21 and the vibration member 22 may be employed. For example, when a thin urethane blade is molded, it is integrally formed by molding on an existing resin film such as PET having a higher hardness than urethane. As a result, the nip portion of the flade member needs a sharp edge, but the handling of the cutting work for that purpose is improved. In this case, after integrally cutting PET and urethane, the PFT side is bonded and attached to the vibration member 22.
[0084]
The blade member 21 is preferably formed of a material having at least a low affinity with the toner used. This prevents the toner from adhering to and sticking to the surface of the blade member 21 and can reduce the occurrence of poor cleaning over time.
[0085]
In this case, conversely, by using a material having a low affinity with the surface of the blade member 21 as an external additive added to the outside of the toner, the external additive of the toner adheres to and adheres to the surface of the blade member 21. Thus, the occurrence of poor cleaning over time can be reduced, and when wax necessary for fixing is externally added to the toner surface, filming due to this can be reduced.
[0086]
The vibration member 22 is made of a material that can vibrate and has higher rigidity than the elastic blade member 21, for example, a metal member such as a mild steel plate or a SUS plate, or a resin molded member in which carbon or glass fiber is mixed. Yes. The vibration member 22 has one end fixed to the fixing portion 24 and the other end as a free end 23a, and the blade member 21 is attached to the free end. The fixing unit 24 is fixed to the housing 25 of the cleaning device as shown in FIG.
[0087]
The vibration member 22 functions as a holder for the blade member 21 and is also a member that determines the pressing force and contact angle of the blade member 21 against the image carrier 11. That is, in the conventional blade, the pressing force of the blade nip portion to the image carrier is applied by the restoring force of the elastic blade itself. On the other hand, in this cleaning device, the blade member 21 has a thin member configuration to increase the propagation efficiency of vibration, and the pressing force of the blade member 21 alone cannot be secured. The pressing force to the image carrier 11 is applied to the image carrier 21. A member (auxiliary member) for separately applying a pressing force can also be used.
[0088]
As a result, the vibration propagation efficiency is increased while using a thin elastic blade member, and a nip corresponding to the warpage of the blade member and the waviness of the surface of the image carrier can be stably formed, and a reliable cleaning performance can be obtained. It is done.
[0089]
The vibration means 23 applies vibration to the vibration member 22, and here, a piezoelectric element as an electromechanical conversion element, particularly a plate-like (single plate) piezoelectric element is used. By using a plate-like piezoelectric element as the vibration means 23, it is possible to constitute a vibration means that can easily obtain a displacement amount at low cost and can electrically change the vibration amount of the blade member 21. .
[0090]
As shown in FIGS. 5 and 6, a plurality of the vibration means 23 are arranged in the axial direction (width direction) of the image carrier 11. The number of vibration means 23 may be one, but by arranging a plurality of vibration means 23 at intervals, it is easy to obtain uniformity of vibration in the width direction of the vibration member 22. Although it is conceivable to provide one long piezoelectric element, in the case of a plate-like piezoelectric element, it is preferable to dispose a plurality of piezoelectric elements at intervals because of bending deformation caused by expansion and contraction in the plate surface direction. .
[0091]
The vibration means 23 is provided near the tip of the vibration member 22 on the image carrier 1 side, that is, on the surface opposite to the blade member 21 and the attachment surface of the free end 22b. Depending on the configuration of the vibration member 22, the attachment position of the vibration means 23 is not particularly limited as long as the vibration member 23 can vibrate the vibration member 22 between the fixed end of the vibration member 23 and the blade tip (free end). .
[0092]
As shown in FIG. 4, the single-plate piezoelectric element constituting the vibration means 23 is printed and fired on both surfaces of the piezoelectric layer 23a such as lead zirconate titanate, that is, on the joint surface with the vibration member 22 and on the opposite surface. Electrodes 23b and 23c made of Ag or the like. When a voltage of 100 to 300 V is applied to a piezoelectric element (piezoelectric layer 23 a) having a thickness of 0.3 to 0.5 mm polarized using the electrodes 23 b and 23 c, shrinkage deformation in the plate surface direction is caused. As a result, it is possible to apply deformation vibration that bends the vibration member 22. This bending vibration has a good deformation efficiency when the rigidity of the piezoelectric element (vibration means 23) and the vibration member 22 is substantially the same, for example, a metal vibration member 22 having a thickness of 0.2 to 0.4 mm, or a thickness of 0. It is preferable to use a resin vibration member of 3 to 1.0 mm.
[0093]
As shown in FIG. 7, the cleaning device 16 includes a drive circuit 28 for applying a drive signal Pv in common to the piezoelectric elements constituting the plurality of vibration means 23 of the vibration blade 20. ing. In this way, when a plurality of vibration means are provided in the width direction of the blade member, driving with a common drive circuit can improve the uniformity of vibration in the width direction of the blade member.
[0094]
The drive circuit 28 is controlled by the main control unit 29 of the image forming apparatus, and supplies the drive signal Pv to the vibration means 23 at a predetermined timing. In this embodiment, the entire width in the width direction of the image carrier 11 is cleaned with one vibration blade 20, but a plurality of vibration blades 20 are provided to cover the entire width in the width direction. In this case, each of the vibration means of the plurality of vibration blades 20 can be driven by a common drive circuit.
[0095]
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 to the vibration member 22 to electrically By connecting, the electrodes 23c of the plurality of vibration means 23 are commonly connected through the vibration member 22. As a result, the drive signal can be applied 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 it to the vibration member 22 with a thin adhesive layer. Alternatively, the direct contact may be performed using a conductive adhesive. Good.
[0096]
In the cleaning device 16 configured as described above, a drive signal Pv having a required frequency is given from the drive circuit 28 to the plurality of vibration means 23 to bend and deform the piezoelectric elements constituting the plurality of vibration means 23. Thus, the vibrating member 22 vibrates, and the blade member 21 vibrates due to the vibration of the vibrating member 22.
[0097]
Here, the vibration member 22 is vibrated by the vibration means 23 to vibrate the tip of the blade member 21, thereby preventing the spherical toner from rotating due to frictional force and vibrating the toner near the blade nip portion. The vibration toner wall is formed, and the spherical member and the small-diameter toner are prevented from entering the blade nip portion by preventing the blade member 21 from being turned up in the moving direction (arrow A direction) of the image carrier 11. It is possible to prevent the defective cleaning of the spherical toner and the small diameter toner. Further, the stress from the blade member to the image carrier is also reduced, and as a result, a very great effect is obtained that the durability of the blade member and the image carrier is remarkably improved.
[0098]
Here, in the configuration shown in FIG. 7, the main control unit 29 detects the toner adhesion amount on the surface of the image carrier 11 based on the detection signal of the density sensor 19, and drives the drive circuit 28 based on the detection result. By controlling, the vibration amount of the blade member 21 can be changed. In this case, since the toner condition close to the tip of the blade member 21 can be detected, the cleaning condition can be optimized so that a good cleaning state is maintained.
[0099]
In addition, by making it possible to change the vibration amount of the blade member 21 in this way, for example, foreign matter and toner collected on the blade member 21 by changing the vibration amount during and without image formation. Can be removed.
[0100]
Further, in addition to the toner adhesion amount on the image carrier 11, the amount of vibration can be changed based on the number of output sheets (number of times of image formation), environmental conditions, and toner replenishment amount, so that optimum cleaning conditions can be maintained. Become.
[0101]
In this case, by changing the amount of vibration of the blade member 21 based on the count value of the number of output sheets (number of image formations), the deterioration of the blade member 21 can be predicted with a simple configuration, so that the cleaning conditions can be optimized. become. Furthermore, by changing based on the detection result of the environmental condition, the mechanical contact condition of the blade member 21 can be changed, and the cleaning condition can be optimized. Furthermore, by changing based on the detection result of the toner replenishment amount, the cleaning condition can be optimized without arranging a sensor near the image carrier.
[0102]
Next, a second embodiment of the vibration blade 20 of the cleaning device 16 will be described with reference to FIGS.
In this embodiment, a multilayer piezoelectric element is used as the excitation means 33 that applies vibration to the vibration member 22. Since the multilayer piezoelectric element has a high natural frequency of 50 to 100 kHz and a large displacement force, the multilayer piezoelectric element is high even if the plate thickness of the vibrating member 22 is increased by using the multilayer piezoelectric element. A configuration capable of responding up to the frequency becomes easy.
[0103]
Here, the laminated piezoelectric element constituting the excitation means 33 is formed by alternately laminating, for example, 100 μm piezoelectric layers 33a and internal electrodes 33b per layer, and the internal electrodes 33b are alternately drawn to both end faces to end face electrodes (external electrodes). In this case, the displacement in the d33 direction, which is the displacement in the stacking direction, is used.
[0104]
It is also possible to adopt a configuration utilizing a displacement in the plane direction perpendicular to the stacking direction in which a plurality of layers are stacked using stacked piezoelectric elements, that is, a displacement in the d31 direction. The cost of the driver (driving 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 that constitutes the vibration means 23.
[0105]
Here, the vibration member 22 has a thin plate shape that can be elastically deformed, and a fixed end of the vibration member 22 is fixed to a fixing member 35 that is a highly rigid holder having a support portion 35a facing the vibration member 22. The laminated piezoelectric element which is the vibration means 33 is disposed between the support portion 35 a of the member 35 and the vibration member 22. The blade member 21 is disposed in the tip region of the surface of the vibration member 22 opposite to the vibration means 233 so that vibration from the vibration means 33 is transmitted through the vibration member 22.
[0106]
As described above, by providing the excitation means between the fixed portion and the vibration member, vibration can be efficiently transmitted to the vibration member.
[0107]
Further, as shown in FIG. 9, 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 narrow width, the vibration means 33 may be configured to be one if a multilayer piezoelectric element having a large cross-sectional area is used.
[0108]
Next, a third embodiment of the vibration blade 20 of the cleaning device 16 will be described with reference to FIGS. 10 and 11.
In this embodiment, the holder 44 is fixed to the side end surface of the vibration member 42 to which the blade member 21 is attached, and the stacked piezoelectric element 43 is fixed between the support portion 44 a of the holder 44 and the side end surface of the vibration member 42. . In this case, the vibration member 42 vibrates in the same direction due to the displacement of the piezoelectric element 43 in the direction of the arrow in the figure.
[0109]
Here, in order to apply a drive signal to the piezoelectric elements constituting the excitation means 23, 33, 43 according to the first to third embodiments, the drive circuit is configured by a common drive circuit as described above. This drive circuit can be composed of a function generator for generating a pulse signal and a power source (driver) for amplifying the signal generated therefrom.
[0110]
As described above, when a plurality of piezoelectric elements are arranged and operated, or when it is necessary to arrange a plurality of color image carriers and cleaning blades as in a tandem machine, a plurality of function generators and power supplies are used. Alternatively, the same power supply may be divided into a plurality of branches, and each may be applied to the piezoelectric element. However, if the number of branches is large, use a power supply with a sufficient output.
[0111]
In addition, when used in an image forming apparatus or a process cartridge described later, a power supply with a smaller space is often preferable. Therefore, it is preferable to use a driver in which a function generator and a power supply are integrated as described above. At this time, as described above, drive control is performed from the main control unit for operating the image forming apparatus and the entire process cartridge, and the drive condition is changed according to the situation, image formation, or non-operation is performed. The operation of the piezoelectric element can be controlled in synchronization with the operation sequence during image formation.
[0112]
Next, the toner that is the image forming particle used in the first invention will be described.
First, 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, an average circularity of less than 0.95, and an irregular shape that is too far from the spherical shape. With the shape, a high-quality image without transferability and dust cannot be obtained. Accordingly, the circularity of the spherical toner is preferably 0.95 or more.
[0113]
As a method for measuring the shape, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. is there. A toner with an average circularity of 0.95 or more, which is a value obtained by dividing the perimeter of an equivalent circle with the same projected area obtained by this method by the perimeter of the actual particle, is a high-definition image with a reproducibility of an appropriate density. It was found to be effective in forming. The definition of circularity is shown in FIG.
[0114]
The circularity of the toner is more preferably an average circularity of 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 measurement method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is obtained by performing a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes and measuring the shape and distribution of the toner with the above apparatus with a dispersion concentration of 3000 to 10,000 / μl. .
[0115]
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 (trade name, manufactured by Coulter), connected to a personal computer (IBM), and using dedicated analysis software (Coulter). The Kd value was set using standard particles of 10 μm, and the aperture current was set at an automatic setting. As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. In addition, ISOTON-II (manufactured by Coulter Scientific Japan, trade name) can be used.
[0116]
As a measuring method, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous 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 a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and a weight average particle diameter was determined by measuring 50,000 counts of toner having a size of 2 μm or more using a 100 μm aperture tube.
[0117]
Next, a method for producing the polymerized / spherical toner will be described.
Examples of a method for producing a toner having a circularity of 0.960 to 0.998 used in the image forming apparatus include suspension polymerization, emulsion aggregation, dispersion polymerization, interfacial polymerization, dissolution suspension, and phase inversion emulsification. The manufacturing method by wet granulation, such as these, is mentioned. A toner having a high degree of circularity can also be produced by pulverizing and classifying the melt-kneaded product by heat treatment of the toner, but this is not preferable in terms of energy efficiency.
[0118]
Among the wet granulation methods described above, suspension polymerization and dispersion polymerization methods are superior in that a toner with a high degree of circularity can be obtained stably, a sharp particle size distribution can be obtained, and in terms of toner charge control. ing. Further, the dissolution suspension method is excellent in that a polyester resin 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.
[0119]
(Suspension polymerization method)
For a specific monomer described later, a dispersion stabilizer, a colorant, and, if necessary, a crosslinking agent, a charge control agent, a release agent, and the like are uniformly dispersed by a ball mill or the like, and then a polymerization initiator is added thereto. In addition, a monomer phase is obtained, and the aqueous dispersion medium phase prepared by stirring with the monomer phase in advance is placed in a stirring tank, stirred with a homogenizer, etc., and the resulting suspension is heated after nitrogen substitution and subjected to a polymerization reaction. By completing the above, colored resin particles are obtained. By washing and drying, colored toner particles can be obtained.
[0120]
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 such as styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, butyl styrene, octyl styrene and the like, and styrene monomers are most preferable. .
[0121]
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, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, n methacrylate Α-methylene aliphatic monocarboxylic esters such as octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, acrylic acid or methacrylic acid such as 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 such as vinyl naphthalene and the like can be used, and these monomers can be used alone or in combination.
[0122]
In the suspension polymerization method, in order to form a crosslinked polymer in the monomer composition, the following crosslinking agent may be present for suspension polymerization. As a 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.
[0123]
When the amount of the crosslinking agent used is too large, the toner is difficult to be melted by heat, and heat fixability and heat pressure fixability are inferior. In addition, if the amount of the crosslinking agent used is too small, properties such as blocking resistance and durability required for the toner are deteriorated, and in heat roll fixing, a part of the toner does not completely adhere to the paper and does not adhere to the roll surface. A cold offset occurs in which it 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 with respect to 100 parts by weight of the polymerizable monomer.
[0124]
The following can be used as the dispersion stabilizer in the suspension polymerization method. That is, water-soluble polymers such as polyvinyl alcohol, starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, sodium polyacrylate, sodium polymethacrylate, barium sulfate, calcium sulfate, barium carbonate, magnesium carbonate, calcium phosphate, talc, clay Diatomaceous earth, metal oxide powder, etc. are used. These are preferably used in the range of 0.1 to 10% by weight based on water.
[0125]
In the suspension polymerization method, the polymerization initiator may be added to the dispersion containing the monomer composition after granulation, but the polymerization initiator is uniformly applied to the individual monomer composition particles. Is preferably contained in the monomer composition before granulation. Such polymerization initiators include 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis- (cyclohexane-1- Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo or diazo polymerization initiators such as azobisbutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxide , Peroxide polymerization initiators such as 2,4-dichloroylbenzoyl peroxide and lauryl peroxide.
[0126]
In the suspension polymerization method, a magnetic toner containing a magnetic material is possible. In order to obtain a magnetic toner, magnetic particles may be added to the monomer composition. Examples of the magnetic material 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.
[0127]
As the magnetic particles, particles having a particle size of 0.05 to 5 μm, preferably 0.1 to 1 μm are used. When producing a small particle toner, magnetic particles having a particle size of 0.8 μm or less are used. It is preferable to do. The magnetic particles are preferably contained in 10 to 60 parts by weight in 100 parts by weight of the monomer composition. These magnetic particles may be treated with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, or an appropriate reactive resin. In this case, although depending on the surface area of the magnetic particles or the density of hydroxyl groups present on the surface, the surface treatment agent is usually 5 parts by weight or less, preferably 0.1 to 3 parts by weight with respect to 100 parts by weight of the magnetic particles. Thus, sufficient dispersibility in the polymerizable monomer is obtained, and the toner physical properties are not adversely affected.
[0128]
(Emulsion polymerization method)
Next, a method for producing spherical toner particles by the emulsion polymerization method will be described.
The emulsion polymerization method is a method capable of producing a particle size suitable as a toner by agglomerating while controlling particles of submicron order. The toner produced by this production method is characterized by a tendency that the distribution of particle size (toner particle size) tends to be quite narrow. As a method for spheroidizing a toner, a method for producing completely spherical toner particles by spray drying a latex obtained by an emulsion polymerization method has been proposed for a long time.
[0129]
(Dispersion polymerization)
A polymer dispersant that dissolves in the hydrophilic organic liquid is added to the hydrophilic organic liquid, and the polymer that is dissolved in the hydrophilic liquid is swollen by the hydrophilic liquid, or It is produced by adding one or two or more kinds of vinyl monomers which are hardly dissolved and polymerizing. Also included is a reaction in which polymer particles having a particle size distribution smaller than the target particle size and having a narrow particle size distribution are used to grow in the above-described system. 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.
[0130]
The hydrophilic organic liquid as a monomer diluent used during the formation of the particles and during the seed particle growth reaction includes methyl alcohol, ethyl alcohol, modified ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, s-butyl alcohol, t-amyl alcohol, 3-pentanol, octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, alcohols such as ethylene glycol, glycerin and diethylene glycol, methyl Cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monome Ethers, such as ether alcohols such as diethylene glycol monoethyl ether as a representative.
[0131]
These organic liquids can be used alone or in a mixture of two or more. In addition, by using the organic liquid other than alcohols and ether alcohols together with the above-described alcohols and ether alcohols, the organic liquid can be used under the condition that the organic liquid is not soluble in the generated polymer particles. It is possible to suppress the size of the generated particles, the coalescence of the seed particles, and the generation of new particles by carrying out the polymerization while changing the SP value of each.
[0132]
The organic liquid used in this case includes hydrocarbons such as hexane, octane, petroleum ether, cyclohexane, benzene, toluene, xylene, halogenated hydrocarbons such as carbon tetrachloride, trichloroethylene, tetrabromoethane, and ethyl ether. , Ethers such as dimethyl glycol, siloxane and tetrahydrofuran, acetals 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, formic acid, acetic acid, propionic acid, nitropropene, nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethyl sulfoxide, dimethylforma Sulfur, such as de, nitrogen-containing organic compounds, other water is also included.
[0133]
Further, the type and composition of the mixed solvent can be changed at the start of polymerization, during polymerization, and at the end of polymerization, respectively, and the average particle size, particle size distribution, drying conditions and the like of the produced polymer particles can be adjusted.
[0134]
Suitable examples of the polymer dispersant used at the time of producing seed particles or growing particles include 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 acrylic monomers containing hydroxyl groups such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-methacrylic acid β- Hydroxypropyl, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate Glycerol monoacrylate, glycerol 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, etc. Esters of compounds containing vinyl alcohol and carboxyl groups, 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 , Vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, etc. Limer or copolymer, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene laurylphenyl Polyoxyethylenes such as ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester, and celluloses such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, or the hydrophilic monomer and styrene, α-methylstyrene, vinyl Those having a benzene nucleus such as toluene or derivatives thereof, acrylonitrile, methacrylonitrile, Copolymers with acrylic acid or methacrylic acid derivatives such as chloramide, and copolymers with crosslinkable monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, divinylbenzene and the like can also be used.
[0135]
These polymer dispersants are appropriately selected depending on the hydrophilic organic liquid to be used, the seeds of the intended polymer particles, and the production of the seed particles or the growth particles. In order to prevent stericity mainly, a material having high affinity and adsorbability to the surface of the polymer particles and high affinity and solubility to the hydrophilic organic liquid is selected. Further, in order to enhance the repulsion between particles in a three-dimensional manner, a molecular chain having a certain length, preferably a molecular weight of 10,000 or more is selected. However, if the molecular weight is too high, the viscosity of the liquid is remarkably increased, the operability and the stirrability are deteriorated, and the precipitation probability of the produced polymer on the particle surface varies. In addition, it is effective for stabilization to allow a part of the monomer of the polymer dispersant mentioned above to coexist with the monomer constituting the target polymer particle.
[0136]
Further, together with these polymer dispersants, metals such as cobalt, iron, nickel, aluminum, copper, tin, lead, magnesium or alloys thereof (particularly those having a particle size of 1 μm or less are preferable), iron oxide, copper oxide, nickel oxide, Inorganic compound fine powders of oxides such as zinc oxide, titanium oxide, silicon oxide, higher alcohol sulfate ester salts, alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters and other anionic surfactants, alkylamine salts, Amine salt types such as amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, and quaternary ammonia such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridium salt, alkylisoquinolinium salt, benzethonium chloride Um salt-type cationic surfactants, fatty acid amide derivatives, nonionic surfactants such as polyhydric alcohol derivatives, for example amino acids such as alanine type "for example dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine" Even when the amphoteric surfactant of the type or betaine type is used in combination, the stability of the produced polymer particles and the improvement of the particle size distribution can be further enhanced.
[0137]
In general, the amount of the polymer dispersant used for producing the seed particles varies depending on the type of the polymerizable monomer for forming the target polymer particles, but is 0.1% by weight to 10% by weight with respect to 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, there is little effect on diameter reduction.
[0138]
The vinyl monomer is soluble in a hydrophilic organic liquid. For example, styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, α-methyl styrene, p-ethyl. Ethylene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene Styrenes such as pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, 3,4-dichloro styrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic Isobutyl acid, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, acrylic 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, 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 , Vinyl halides such as acrylic acid or methacrylic acid derivatives such as methacrylonitrile and acrylamide, 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.
[0139]
In addition, 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 improve offset resistance. Preferred crosslinking agents include divinylbenzene, divinylnaphthalene and their aromatic divinyl compounds, 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 compounds having the above vinyl groups can be mentioned, and these are used alone or as a mixture.
[0140]
When the growth polymerization reaction is subsequently performed using the seed particles thus crosslinked, the inside of the growing polymer particles is crosslinked. 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 can be obtained.
[0141]
Examples of the purpose of adjusting the average molecular weight include compounds having a large chain transfer constant in the presence of polymerization, such as low molecular compounds having a mercapto group, carbon tetrachloride, and carbon tetrabromide.
[0142]
Examples of the polymerization initiator for the monomer include azo polymerization initiators such as 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile), and lauryl. Peroxide polymerization initiators such as peroxide, benzoyl peroxide and t-butyl peroctoate, peroxide polymerization initiators such as potassium persulfate, and systems using sodium thiosulfate, amine, etc. in combination with this Used. The polymerization initiator concentration is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the vinyl monomer.
[0143]
The polymerization conditions for obtaining seed particles are determined by the polymer dispersant in the hydrophilic organic liquid, the concentration of the vinyl monomer, and the compounding ratio according to the target average particle size and target particle size distribution of the polymer particles. Is done. Generally, if the average particle size of the particles is to be reduced, the concentration of the polymer dispersant is set high, and if the average particle size is to be increased, the concentration of the polymer dispersant is set low. On the other hand, if the particle size distribution is to be very sharp, the vinyl monomer concentration is set low, and if a relatively wide distribution may be used, the vinyl monomer concentration is set high.
[0144]
Particles are produced by completely dissolving the polymer dispersion stabilizer in a hydrophilic organic liquid, and then one or more vinyl monomers, a polymerization initiator, and other inorganic fine powders, surfactants, dyes if necessary. Add pigment, etc., and stir at normal speed of 30 to 300 rpm, preferably at low speed, and at a speed that makes the flow in the tank uniform using a turbine type stirring blade rather than a paddle type However, the polymerization is carried out by heating at a temperature corresponding to the polymerization rate of the polymerization initiator used.
[0145]
In addition, since the temperature at the initial stage of polymerization has a great influence on the particle type to be generated, it is preferable to increase the temperature to the polymerization temperature after adding the monomer and to dissolve the polymerization initiator in a small amount of solvent. In the 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. In order to perform the polymerization in a high polymerization rate range, a polymerization time of 5 to 40 hours is required, but the polymerization is stopped in a desired particle size, particle size distribution state, or a polymerization initiator is sequentially added, The polymerization rate can be increased by carrying out the reaction under high pressure.
[0146]
After completion of the polymerization, the polymer slurry may be used as it is in the dyeing process, or after removing unnecessary fine particles, residual monomers, polymer dispersion stabilizer, etc. by operations such as sedimentation separation, centrifugation, and decantation. However, if the dispersion stabilizer is not removed, the stability of the dyeing is higher and unnecessary aggregation is suppressed.
[0147]
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, the dye is dissolved in the solvent before or after this, the dye is infiltrated into the resin particles and colored, and then the organic solvent is removed. In the method for producing a dyed toner, the relationship between the solubility of the dye in the organic solvent (D1) and the solubility of the dye in the resin of the resin particle A (D2) is (D1) / (D2) A dye satisfying ≦ 0.5 is selectively used. As a result, a toner in which the dye has penetrated (diffused) to the deep part of the resin particles can be efficiently produced.
[0148]
Solubility herein is defined as measured at a temperature of 25 ° C. The solubility of the dye in the resin has the same definition as the solubility of the dye in the solvent, and means the maximum amount that the dye can be contained in the resin in a compatible state. Observation of the dissolved state or the deposited 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 direct observation method described above. In this method, a liquid having a solubility coefficient close to that of the resin, that is, a solvent that dissolves the resin well, may be used, and the solubility of the dye in this solvent may be determined as the solubility in the resin.
[0149]
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 from the solubility (D1) of the dye in the organic solvent used as described above. Need to be. Further, (D1) / (D2) is preferably 0.2 or less. The dye is not particularly limited as long as it satisfies the above-mentioned solubility characteristics, but water-soluble dyes such as cationic dyes and anionic dyes may have a large environmental fluctuation, and the electrical resistance of the toner is lowered, resulting in a decrease in transfer rate. Since there is a possibility, use of a vat dye, a disperse dye, and an oil-soluble dye is preferable, and an oil-soluble dye is particularly preferable. Also, several kinds of dyes can be used in combination depending on the desired color tone.
[0150]
The ratio (weight) between the dye to be dyed and the resin particles is arbitrarily selected according to the degree of coloring, but is usually used in a ratio of 1 to 50 parts by weight of the dye with respect to 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 the dyeing solvent and a styrene-acrylic resin having an SP value of about 9 is used as the resin particle, examples of the dye that can be used include the following: And dyes such as
[0151]
CI SOLVENT YELLOW (6,9,17,31,35,1,102,103,105)
CI SOLVENT ORANGE (2,7,13,14,66)
CI SOLVENT RED (5,16,17,18,19,22,23,143,145,146,149,150,151,157,158)
CI SOLVENT VIOLET (31,32,33,37)
CI SOLVENT BLUE (22,63,78,83-86,91,94,95,104)
CI SOLVENT GREEN (24,25)
CI SOLVENT BROWN (3,9) etc.
[0152]
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 Co., Ltd. 2, Violet-1, Green-1,2,3, Black-1,4,6,8, Sudan dyes manufactured by BASF, Yellow-140, 150, Orange-220, Red-290, 380, 460, Blue -670 and Mitsubishi Kasei's Dial Resin, Yellow-3G, F, H2G, HG, HC, HL, Orange-HS, G, Red-GG, S, HS, A, K, H5B, Violet-D, Blue- Oil color made by J, G, N, K, P, H3G, 4G, Green-C, Brown-A and Orient Chemical, 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, Sumitomo Chemical's Sumiplast, Blue GP, OR, Red FB, 3B, Yellow FL7G, GC, Nippon Kayaku Kayalon, Polyester Black EX-SH3, Kaya Set Red-B Blue 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 at the time of dyeing, and is not limited to the above example.
[0153]
As an organic solvent for dyeing used for dyeing a resin particle, one in which the resin particle to be used does not dissolve or that slightly swells, specifically, the difference in solubility parameter (SP value) is 1. 0.0 or more, preferably 2.0 or more is used. For example, for styrene-acrylic resin particles, alcohols such as methanol, ethanol and n-propanol having a high SP value, or n-hexane and n-heptane having a low SP value are used. If the SP value difference is too large, wetting with respect to the resin particles becomes poor, and good dispersion of the resin particles cannot be obtained. Therefore, the optimum SP value difference is preferably 2 to 5.
[0154]
After dispersing the resin particles in the organic solvent in which the dye is dissolved, it is preferable to keep the liquid temperature below the glass transition temperature of the resin particles and stir. Thereby, it becomes possible to dye while preventing aggregation of the resin particles. The stirring method 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 conditions. When the heating temperature exceeds the glass transition temperature, fusion between the resin particles occurs. The method for drying the slurry after dyeing is not particularly limited, and may be directly dried under reduced pressure without filtering or filtering after filtration. In the present invention, the colored particles obtained by air-drying or drying under reduced pressure after filtering are reproduced with almost no aggregation and almost no deterioration in the particle size distribution of the charged resin particles.
[0155]
(Dissolution suspension method)
Next, a method for producing spherical toner particles by the dissolution suspension method will be described.
The dissolution suspension method is a method in which a resin is dissolved in a solvent to prepare 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.
[0156]
As the aqueous medium, water alone may be used, but a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), and the like.
[0157]
As the resin to be used, styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and a polymer of a substituted product thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, 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 copolymers such as lene-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 resins, chlorinated paraffin, paraffin wax and the like can be mentioned, and these can be used alone or in combination.
[0158]
As a solvent that can be used for oil phase preparation, it is preferable that the boiling point is volatile with a temperature of less than 100 ° C. from the viewpoint of easy removal. 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 preferable. The amount of solvent used with respect to 100 parts of the toner composition is usually 10 to 900 parts.
[0159]
In the oil phase preparation, a colorant (or colorant masterbatch), a release agent, and a charge control agent, which are other toner compositions, are simultaneously added and mixed when forming a dispersion in an aqueous medium. However, it is more preferable to mix in the oil phase in advance.
[0160]
Further, other toner raw materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, and may be added after the particles are formed. Good. For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method.
[0161]
For the dispersion of the oil phase and the aqueous phase, all ordinary stirring mixers can be used, but more preferably a homogenizer having a high-speed rotating body and a stator, a high-pressure homogenizer, a ball mill, a bead mill, and a sand mill. Etc. are used.
[0162]
The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, 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 preferable. The emulsifier having rotating blades is not particularly limited, and any emulsifier and disperser that are generally commercially available can be used. For example, Ultra Thalax (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 homomic line flow (manufactured by Special Machine Industries Co., Ltd.), colloid mill (manufactured by Shinko Pantech Co., Ltd.), slasher, trigonal wet pulverizer (manufactured by Mitsui Miike Chemical Co., Ltd.), Cavitron (Eurotech Co., Ltd.) ), Fine flow mill (manufactured by Taiheiyo Kiko Co., Ltd.), and other continuous emulsifiers, CLEARMIX (manufactured by M Technique Co., Ltd.), fill mix (manufactured by Koki Kogyo Co., Ltd.) Etc.
[0163]
When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 10 to 98 ° C. The high temperature condition method is preferred in that the dispersion has a reasonably low viscosity and is easy to disperse.
[0164]
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.
[0165]
Furthermore, 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 emulsification of the toner composition or when volatile components are removed after emulsification.
[0166]
(Sphericalizing of pulverized toner)
The toner by the pulverization / classification method is indefinite as it is, and depending on the pulverization method, the circularity is 0.930 to 0.950, and the circularity is not 0.960 to 0.998. The degree of circularity can be increased by mechanical spheroidization treatment or heat treatment as described below, and toner with a circularity of 0.960 to 0.998 can be obtained.
[0167]
[Mechanical processing]
For example, as described in JP 09-087441 A, a method using a turbo mill (manufactured by Turbo Industry), a kryptron (manufactured by Kawasaki Heavy Industries), a Q-type mixer (manufactured by Mitsui Mine), a hybridizer (Nara Machinery) ) And mechano-fusion device (made by Hosokawa Micron etc.), the shape of the pulverized toner can be made spherical.
[0168]
[Heat treatment (dry type)]
For example, the shape of the pulverized toner can be made spherical by semi-melting the surface of the toner particles with hot air of 100 to 300 ° C. using a surffusion system (Nippon Pneumatic Industry).
[0169]
[Heat treatment (wet)]
The shape of the pulverized toner can be made spherical by immersing the toner obtained by the pulverization method in a high-temperature liquid at a temperature (about 200 ° C.) at which the toner has plasticity.
[0170]
(Carrier for two-component developer)
In the first invention, the toner can be used as a two-component developer. In this case, the toner may be mixed with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is 100 parts by weight of the carrier. The amount of toner is preferably 1 to 10 parts by weight.
[0171]
As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used.
[0172]
Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, 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.
[0173]
Moreover, you may make conductive powder etc. contain in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
[0174]
In the first invention, the toner can also be used as a one-component magnetic toner that does not use a carrier or a non-magnetic toner.
[0175]
Next, the cleaning property evaluation for the first invention will be described.
First, specific examples (examples) of toner used for evaluation will be described. The toner used in the first invention is not limited to these examples. Further, among the descriptions relating to toner production shown in the following examples, the amounts (parts) of each component are based on weight.
[0176]
[Toner A] (Example of suspension polymerization, high circularity)
Add 40 parts by weight of styrene monomer, 20 parts by weight of carbon black MA100 (manufactured by Mitsubishi Kasei Co., Ltd.) and 0.5 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator. Into a 500 ml four-necked separable flask equipped with a gas introduction tube and a thermometer, the mixture was stirred for 30 minutes at room temperature under a nitrogen stream, and the inside of the flask was replaced with nitrogen. Then, it stirred at 60 rpm in a 70 degreeC hot water bath for 6 hours, and graft carbon black was obtained.
[0177]
The following mixture was then dispersed on a ball mill for 10 hours.
50.0 parts by weight of styrene monomer
14.5 parts by weight of n-butyl methacrylate
1,3-butanediol dimethacrylate 0.5 parts by weight
3.0 parts by weight of t-butylacrylamide sulfonic acid
Low molecular weight polyethylene 2.0 parts by weight
(Mitsui Petrochemical, Mitsui High Wax 210P)
Graft carbon black 30.0 parts by weight
[0178]
After dissolving 1 part by weight of 2,2'-azobisisobutyronitrile and sodium nitrite in this dispersion, it was added to 250 parts by weight of a 2% aqueous solution of polyvinyl alcohol and added to a TK homomixer (Special Machine Co., Ltd.). The mixture was stirred at 6000 rpm for 10 minutes to obtain a suspension.
[0179]
Put the above suspension into a 500 ml four-necked separable flask equipped with a three-one motor driven stirring blade, cooler, gas inlet tube, and thermometer, and stir at room temperature for 30 minutes under a nitrogen stream. Replaced with nitrogen. Thereafter, the mixture was stirred in a hot water bath at 70 ° C. for 8 hours at 90 rpm to complete the polymerization, thereby producing suspended polymer particles. 100 parts by weight of these particles are redispersed in a mixed solution of water / methanol = 1/1 (weight ratio) so that the solid content is 30%, and 3 parts by weight of ditertiary butylsalicylic acid zinc salt is added as a charge control agent and stirred. Thereafter, filtration and drying were performed to obtain colored particles.
[0180]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0181]
This toner is referred to as “toner A”. The circularity of the toner A was 0.985. The weight average particle diameter of the toner A was 5.81 μm.
[0182]
Then, 5 parts by weight of toner A was mixed with a rocking mixer to 95 parts by weight of a silicone-coated carrier (magnetite core material) having a weight average particle diameter of 50 μm to obtain a two-component developer.
[0183]
[Toner B] (dispersion polymerization example, high circularity)
A 500 ml four-necked flask equipped with a stirring blade and a condenser was charged with 3.5 parts by weight of methyl vinyl ether-maleic anhydride copolymer (molecular weight 40,000, manufactured by GAF) and 100 parts by weight of methanol. The mixture was stirred at 0 ° C. for 2 hours to completely dissolve the methyl vinyl ether-maleic anhydride copolymer to prepare a dispersion stabilizer. Then, it cooled to room temperature and injected the following.
[0184]
60.0 parts by weight of styrene
40.0 parts by weight of methyl methacrylate
0.06 parts by weight of t-dodecyl mercaptan
1,3-butanediol dimethacrylate 0.5 parts by weight
[0185]
While stirring these, the inside of the flask was purged with nitrogen gas, and stirring (100 rpm) was continued gently for about 1 hour until the residual oxygen concentration in the system reached 0.1%. Thereafter, the temperature of the thermostatic water bath was raised to 60 ° C., and then 0.2 part by weight of 2,2′-azobisisobutyronitroyl was used as an initiator, and polymerization was continued for 24 hours. The solution began to become cloudy 15 minutes after heating, and was a stable dispersion that became cloudy even after polymerization for 24 hours. As a result of partial sampling and measurement by gas chromatography using an internal standard method, it was confirmed that the polymerization rate was 95%.
[0186]
When the obtained dispersion was cooled and centrifuged at 2000 rpm with a centrifuge, the polymer particles were completely settled and the upper liquid was transparent. The supernatant was removed, and 200 g of methanol was newly added, followed by stirring and washing for 1 hour. The operation of centrifuging and washing with methanol was repeatedly filtered. The product separated by filtration was dried under reduced pressure at 50 ° C. for 24 hours to obtain white powdery resin particles in a yield of 90%.
[0187]
Next, 2 parts by weight of oil black 860 (manufactured by Orienten Chemical Co., Ltd.) was dissolved in 100 parts by weight of methanol by heating, then cooled and filtered through an about 1 μm filter to prepare a dye solution.
[0188]
Next, 30 parts by weight of polymer particles were added to the filtrate and dispersed, and the mixture was heated and stirred at 50 ° C. for 1 hour. Thereafter, the dispersion was cooled to room temperature and filtered to obtain a colored resin fine particle dispersion. Subsequently, ditertiary butylsalicylic acid zinc salt as a charge control agent was dissolved in a water / methanol (1/1) mixed solvent, and 2 parts by weight was added to 100 parts by weight of the colored resin particles. After stirring for 1 hour, it was filtered and dried to obtain colored particles.
[0189]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0190]
This toner is referred to as “toner B”. The circularity of the toner B was 0.983. Toner B had a weight average particle diameter of 5.52 μm. A two-component developer was prepared in the same manner as toner A.
[0191]
[Toner C] (Example of dissolution suspension method with high circularity)
(Toner binder synthesis)
724 parts of bisphenol A ethylene oxide 2-mole adduct, 276 parts of terephthalic acid and 2 parts of dibutyltin oxide are placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and polycondensed at 230 ° C. for 8 hours at normal pressure. The reaction was further carried out 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 an ethyl acetate solution of a toner binder.
[0192]
(Create toner)
In a sealed pot, put 200 parts of the ethyl acetate solution of the toner binder, 5 parts of carnauba wax, 4 parts of copper phthalocyanine blue pigment, 1 part of ditertiary butylsalicylic acid zinc salt, 24 parts using 5 mmφ zirconia beads. Ball mill dispersion was performed for a time to obtain a toner composition.
[0193]
In a beaker, 600 parts of ion-exchanged water, 6 parts of partially saponified polyvinyl alcohol, and 0.3 part of sodium dodecylbenzenesulfonate were uniformly dissolved and dispersed.
[0194]
Next, while maintaining the beaker internal temperature at 20 ° C., the toner composition was charged while stirring at 12000 rpm with a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and the mixture was stirred and emulsified for 3 minutes. Next, this mixed solution was transferred to a flask equipped with a stir bar and a thermometer, 0.3 parts of sodium lauryl sulfate was added, and the mixture was stirred and dissolved at room temperature for 30 minutes. Subsequently, the solvent was removed under reduced pressure at 30 ° C. and 50 mmHg. When the dispersion was analyzed by gas chromatography, the residual ethyl acetate was 50 ppm with respect to the toner particles. 120 parts of 35% concentrated hydrochloric acid was added to dissolve the tricalcium phosphate, followed by filtration. The operation of redispersing the resulting cake in distilled water and filtering was repeated three times, followed by drying under reduced pressure at 40 ° C. for 24 hours. Colored particles were obtained.
[0195]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0196]
This toner is referred to as “toner C”. The circularity of the toner C was 0.980. The weight average particle diameter of the toner C was 5.41 μm. A two-component developer was prepared in the same manner as toner A.
[0197]
[Toner D] (Comparison example with pulverized toner, low circularity)
The following raw materials were sufficiently mixed with a Henschel mixer, and then kneaded with a small two-roll mill at 150 ° C. for 2 hours.
Binder resin (styrene-methyl acrylate copolymer) 100.0 parts by weight
Colorant (carbon black # 44, manufactured by Mitsubishi Carbon Corporation) 10.0 parts by weight
Charge control agent (ditertiary butylsalicylic acid zinc salt) 2.0 parts by weight
(Orient Chemical Bontron E-84)
Carnauba wax 5.0 parts by weight
[0198]
The obtained kneaded product was coarsely pulverized with a pulverizer equipped with a 2 mm screen, then pulverized with a lab jet, and classified with 100 MZR to obtain colored particles.
[0199]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0200]
This toner is referred to as “toner D”. The circularity of the toner D was 0.930. Toner D had a weight average particle diameter of 5.73 μm. A two-component developer was prepared in the same manner as toner A.
[0201]
[Toner E] (Comparison example by mechanical treatment of pulverized toner, circularity is slightly low)
The colored particles obtained in the production example of the toner D were processed at 12,000 rpm for 10 minutes using a hybridizer manufactured by Nara Machinery, to obtain colored particles.
[0202]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0203]
This toner is designated as Toner E. The circularity of the toner E was 0.945.
Toner E had a weight average particle diameter of 5.21 μm. A two-component developer was prepared in the same manner as toner A.
[0204]
[Toner F] (Example of mechanical processing of pulverized toner, circularity is slightly high)
The colored particles obtained in the production example of the toner D were processed at 12,000 rpm for 30 minutes using a hybridizer manufactured by Nara Machinery, to obtain colored particles.
[0205]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0206]
This toner is referred to as “toner F”. The circularity of the toner F was 0.968. Toner F had a weight average particle diameter of 5.26 μm. A two-component developer was prepared in the same manner as toner A.
[0207]
[Toner G] (Example of heat treatment of ground toner, high circularity)
The colored particles obtained in the production example of Toner D are treated twice with a heat treatment temperature of 250 ° C., a hot air flow rate of 1000 l / min, and a supply air flow rate of 100 l / min using a Nippon Pneumatic Surffusion System to obtain colored particles. It was.
[0208]
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 for 2 minutes with a Henschel mixer and sieved to obtain a toner.
[0209]
This toner is referred to as “toner G”. The circularity of the toner G was 0.970. The weight average particle size of the toner G was 5.56 μm. A two-component developer was prepared in the same manner as toner A.
[0210]
Using the toners A to G described above, the transferability and the cleaning property in the image forming apparatus according to the present invention were evaluated.
[0211]
The charging and developing conditions were as follows, and were constant during the evaluation.

[0212]
In addition, as described above, the application of the drive voltage to the piezoelectric element constituting the vibration means of the vibration blade according to the present invention amplifies the function generator for generating the pulse signal and the signal generated from the function generator. In order to confirm the voltage actually applied to the piezoelectric element through a power source, the amplified voltage was branched and monitored by an oscilloscope.
[0213]
The evaluation of the cleaning property intended by the present invention and the transfer rate improved when using spherical toner were evaluated as follows.
(Evaluation of transfer rate)
In the evaluation (measurement) of the transfer rate, the operation is stopped while a solid image is being output on the surface of the image carrier, and toner images between the developing unit and the transfer unit and between the transfer cleaning unit and It was made to transfer on white paper with the Scotch tape (made by Sumitomo 3M Co., Ltd.), and it was measured with the Macbeth reflection densitometer RD514 type | mold.
[0214]
At this time,
Tape density between developer and transfer area: Ddt
Tape density between transfer part and cleaning part: Dtc
Density just transferred scotch tape on white paper: Dref
And the transfer efficiency was calculated by the following equation (1).
[0215]
[Expression 1]

[0216]
(Cleaning evaluation)
The cleaning property was also evaluated using a scotch tape in the same manner as the previous 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 Scotch tape (manufactured by Sumitomo 3M Co., Ltd.), and it is similarly transferred with the Macbeth reflection densitometer RD514. Measured, the difference from the blank (only white paper with scotch tape only) is 0.01 or less as good (indicated as “O” in the evaluation result table), and exceeds that (concentration is NG (defective).
[0217]
(Comparison by difference in circularity of toner)
Evaluation was performed with an image forming apparatus equipped with the vibration blade 20 (FIGS. 8 and 9) according to the second embodiment described above. Since it is difficult to judge the quality of the cleaning performance at the initial stage of the image forming operation, the A3 paper in which the occurrence of the cleaning failure is clearly confirmed with the toner C produced by the conventional blade cleaner and the solution suspension polymerization. The evaluation after 50,000 sheets was evaluated with the toners A to G described above.
[0218]
As the blade cleaner, a conventional blade (blade portion thickness: 3 mm) and the vibration blade 20 according to the second embodiment (vibration member thickness: 0.3 mm, blade member thickness: 0.2 mm) were used. Both the pressure (contact pressure) for pressing against the photosensitive member (image carrier 11) is 70 g / cm. ² Unified. In both cases, the blade member was made of polyurethane rubber. The hardness as a bulk was about 70 ° according to JIS-A. A driving voltage having a voltage Vpp of 20 V and a frequency of 20 kHz was applied to all the laminated piezoelectric elements 33 of the vibration blade 20 according to the second embodiment.
[0219]
Actual output is 0.1mg / cm on the photoconductor ² An image pattern is prepared, and this is output for 50000 sheets in the vertical direction of A3 paper. At the stage where the output of 50,000 sheets was completed, as shown in the method for measuring the transfer rate and the cleaning rate, an image pattern that gave a solid image was output halfway and evaluated.
[0220]
The above evaluation results are shown in Table 1. Note that “the blade of the present invention” in the column of the cleaning property in Table 1 means the vibration blade 20 according to the second embodiment as described above. In addition, “NG1” indicates that the background contamination due to poor cleaning occurred on the paper with about 1000 sheets of output, and “NG2” indicates that the background contamination due to poor cleaning occurred on the paper with about 3000 sheets of output. “NG3” means that about 2,500 sheets of output were generated, and background contamination due to poor cleaning occurred on the paper.
[0221]
[Table 1]

[0222]
From Table 1, it can be seen that toners D and E, which are pulverized toners, maintain the cleanability even with a conventional blade that does not vibrate. However, when the circularity is increased by mechanical treatment or heat treatment, It can be seen that the blade does not maintain the cleaning function.
[0223]
As for the transfer rate, as described above, when the circularity is high, the transfer efficiency shows a high value of around 95%. From this point, it can be predicted that the image quality is high, but the circularity is low. Is as low as around 90%. It can be seen that toners D and E, which were good in terms of cleaning properties, have good cleaning properties, but are low in comparison with transfer rates and are not preferable in terms of image quality.
[0224]
As is apparent from Table 1, in the first invention, the spherical toner having a high circularity has vibration of the blade portion, thereby preventing the occurrence of poor cleaning as compared with the conventional blade cleaning. It can be seen that the cleaning property can be maintained even by repeated use.
[0225]
Next, using the toner C produced by the dissolution suspension polymerization method having the highest transfer rate in the above evaluation, the cleaning performance of each vibration blade according to the first to third embodiments including the conventional blade cleaning is used. Evaluated.
[0226]
First, evaluation on the magnitude of the applied voltage Vpp will be described.
In the same manner as in the evaluation experiment described above, the cleaning performance was evaluated after outputting 50,000 sheets of output with each blade. At this time, the frequency of the driving voltage is fixed at 20 kHz, and the vibration blades of the first to third embodiments are evaluated by changing the voltage Vpp of the driving voltage applied to the piezoelectric element to 5, 20, and 30 V, respectively. Simultaneously, the amount of displacement of the tip of the blade was measured with a laser Doppler displacement meter.
[0227]
The amount of fluctuation of the blade at the time of vibration was measured on the cleaning device optically using the laser Doppler displacement meter as described above from the vibrating member or the blade member. . For the measurement, the following equipment manufactured by Graphtec Co., Ltd. was used.
Laser Doppler vibration demodulation unit AT3500
Sensor unit AT0021
[0228]
The results are shown in Table 2. In Table 2, “NG4” means that the background stain has occurred on the paper from the beginning of the output, and “NG5” means that the background stain has occurred on the paper after about 100 sheets of output. .
[0229]
[Table 2]

[0230]
As shown in Table 2, even in the vibration blade (blade cleaning) according to the first invention, when the voltage applied to the piezoelectric element as the vibration means is low, the cleaning performance cannot be maintained, and the conventional blade Is almost the same. In addition, in the case of the vibration blade of the first to third embodiments, it can be seen that the amount of displacement increases as the applied voltage increases. The displacement amount of the conventional blade was also measured, but the displacement amount was 0.01 μm or less which is the measurement lower limit value of the measuring instrument.
[0231]
In the case of the vibration blades of the first to third embodiments, the cleaning performance is maintained in any configuration as long as the voltage applied to the piezoelectric element is increased. This is inferred in relation to the amount of displacement by the laser Doppler displacement meter.
[0232]
According to the previous mechanism and the publicly known technology that has been filed in the past, the stick-slip phenomenon occurs even with the conventional blade, and minute vibrations contribute to cleaning properties. However, with spherical toner, the amount of vibration is small. It is considered that toner slips through and results in defective cleaning (toner wall cannot be formed).
[0233]
As can be seen from the result of the laser Doppler displacement meter, when the amount of displacement due to vibration is small, it is considered impossible to clean the spherical toner. It can be seen from Table 2 that the voltage applied to the piezoelectric element also has a lower limit value of the vibration amount necessary for cleaning the spherical toner.
[0234]
Therefore, as apparent from Table 2, in the first invention, the spherical toner having a high degree of circularity is given a certain amount or more of vibration to the blade portion, so that the cleaning is performed in comparison with the conventional blade cleaning. The occurrence of defects can be prevented. Further, the cleaning property can be maintained even by repeated use.
[0235]
Next, evaluation was made in terms of damage to the photoreceptor (image carrier).
As in the previous evaluation experiment, the cleaning performance was evaluated after outputting 50000 sheets of output with each blade. At this time, the applied voltage Vpp was fixed at 20 V and the frequency was 20 kHz. As the toner, toner C made by a solution suspension polymerization method was used.
[0236]
In this evaluation, the amount of abrasion of the photosensitive layer was measured after outputting 50000 sheets using OPC in order to make the damage to the photoreceptor of the blade more prominent (because amorphous silicon photoreceptors are difficult to scrape). This is because the damage evaluation on the photoconductor is not clear.) The results are shown in Table 3.
[0237]
[Table 3]

[0238]
As shown in Table 3, it can be seen that the amount of film scraping was about 2 μm in the vibration blade according to the first invention, whereas the conventional blade increased to about 4 μm, which is about twice that.
[0239]
This is because the conventional blade has a minute vibration due to the stick-slip phenomenon, but the vibration amount is small and the contact time with the photosensitive member is longer than that of the vibration blade according to the present invention. It is considered that the rubbing force with the photoconductor (which may be considered as the rubbing force integrated with time) is increased, and the film scraping amount of the photosensitive layer is increased.
[0240]
In addition, when the above comparison is performed with an amorphous silicon photoconductor, the change in the film scraping amount for both the vibration blade according to the first embodiment and the conventional blade is 1 μm or less, which is less than the measurement limit of the measuring instrument. Was difficult. However, even if the surface of the amorphous silicon photoconductor is hard, although it is small compared to the conventional OPC, film scraping and scratches are generated, so the vibration blade according to the first invention is conventional. It is presumed that there is an effect in that the durability of the photoreceptor is improved as compared with the above blade.
[0241]
As described above, the vibration blade according to the first aspect of the present invention having a large amount of vibration is effective in that the change in the film thickness of the photosensitive member, in other words, the amount of shaving is low, and the damage to the image carrier is effective. Thus, durability can be improved.
[0242]
Next, the operation timing and vibration width of the vibration means of the vibration blade will be described.
By cleaning the toner on the image carrier, toner at the time of cleaning can be accumulated at the tip of the blade member. In this case, it is possible to perform cleaning with a blade of toner having a nearly circular shape with a high degree of circularity, and it is a toner accumulation in a wider width than described in the mechanism of whether or not, and the amount increases. Sometimes it rides on the blade surface. This toner accumulation may restrict the movement of the blade in some cases.
[0243]
For example, even if the toner hardly adheres to the toner, there is a possibility that the toner may be fixed due to pressure contact between the blade and the photoreceptor, or an additive such as wax contained in the toner is stretched by the blade and the surface of the photoreceptor Things like filming also happen. For this reason, it is preferable in terms of improving durability that the toner accumulation is periodically released and reduced as much as possible. Therefore, it is preferable to change the vibration amount (displacement amount) of the blade member by the vibration means.
[0244]
Therefore, as described above, image forming conditions such as toner consumption, environmental conditions, toner adhesion amount on the image carrier, and the number of printed sheets (number of times of image forming) are detected, and vibration is generated based on the detection result. Drive control of the means.
[0245]
In this case, if the amount of vibration of the piezoelectric element is changed at the normal image formation timing, the cleaning condition changes, so that it is predicted that a cleaning failure will occur. Therefore, control is performed so that the amount of vibration is increased during non-image formation to eliminate toner accumulation, and during image formation, control is performed so as to reduce the amount of vibration in order to maintain cleaning conditions and prevent the occurrence of poor cleaning. The amount of vibration may be controlled by changing the voltage value of the drive signal applied to the vibration means as described above.
[0246]
In addition, in the case of an image forming apparatus that outputs at high speed, it is predicted that the amount of toner consumption is also large. Therefore, in addition to increasing the vibration amount of the blade, an auxiliary member for eliminating toner accumulation is arranged. It can also be done. In the evaluation experiment, a brush (φ8) was disposed at the tip of the blade to eliminate toner accumulation.
[0247]
Next, an embodiment according to the second invention will be described.
First, in the configuration of the image forming apparatus, in the configuration of the image forming apparatus according to the embodiment of the first invention (see FIG. 2), the area (image area) necessary for visualizing the output image with toner is counted. Then, a signal for estimating the amount of toner per unit area is taken into the main control unit.
[0248]
The main control unit also receives a signal from a detection means for detecting the rotational torque of the motor necessary for rotating the image carrier 11, or a signal from a detection means for detecting a drive current for the motor. .
[0249]
As for the configuration of the cleaning device 16, the configuration described as the first embodiment and the second embodiment of the cleaning device 16 of the first invention is used.
[0250]
Further, the drive control for the vibration means 23 of the vibration blade 20 constituting the cleaning device 16 is as described in the embodiment of the first invention.
[0251]
Accordingly, the maintenance and improvement of the cleaning performance by reducing the frictional resistance between the blade member and the image carrier, which is the object of the second invention, will be described.
First, “toner C” described in the first embodiment is used as the toner. The second invention is not limited to an image forming apparatus, a cleaning apparatus, or the like that uses spherical toner.
[0252]
The measurement of the frictional resistance will be described. When the vibration blade according to the second invention is used, the frictional resistance between the blade member 21 and the image carrier 11 is changed by the vibration of the vibration member 22 by the vibration means 23.
[0253]
Here, as a method of directly measuring the frictional resistance force, it was experimentally evaluated using a surface property tester. The tester used was a surface property tester: Tribogear HEIDON TYPE: 14DR (manufactured by Shinto Kagaku).
[0254]
Using this apparatus, the frictional resistance between the blade member and the image carrier 11 due to vibration was experimentally measured. A schematic diagram in this experiment is shown in FIG.
Here, as described in the second embodiment of the first invention, the vibration blade attached to the surface property testing machine uses a vibration element 23 having a piezoelectric element 33 attached to the back surface of the vibration member 22. Yes. As a member that contacts the blade member 21, a glass surface 51 whose surface was cleaned was used. In the normal image forming process, the blade member 21 and the photosensitive layer of the image carrier 11 are in contact with each other. First, in order to clarify how vibration is applied to the blade member 21 is related to the frictional resistance. Moreover, since the measurement environment of the frictional resistance is stabilized by maintaining a uniform surface by washing, glass is used for the surface property testing machine, and the frictional resistance between the blade member 21 and the glass surface 51 is measured. .
[0255]
The surface property tester is a force applied in the lateral direction when the stage 52 attached with the glass surface 51 is moved at a constant direction and speed when a constant load (perpendicular to the glass surface) is applied to the blade member 21. Is measured as a frictional force by a strain gauge 53 attached to the testing machine. At this time, the force applied to the strain gauge 53 and the frictional resistance between the blade and the glass surface are recorded in real time on the alanizing recorder 54.
[0256]
An example (hereinafter referred to as a chart) recorded in the analyzing recorder 54 is shown in FIG. In the figure, an example of measuring the frictional resistance is shown from the state where the stage 52 is stopped. Initially, in a state where the stage 52 is stopped (A region), the frictional resistance is zero, and therefore the value is also shown in the chart. When the stage 52 starts to move, in the region B in the figure, the stage 52 starts to move, and the frictional resistance force also appears on the chart. In the region C, the movement starts, and the frictional resistance between the blade member 21 and the glass surface 52 moves while maintaining a substantially constant value. After a while, the stage 52 stops after reaching a predetermined moving distance.
[0257]
In each area on the chart, the first stage of the B area, where the frictional resistance is maximized is a portion corresponding to the static friction coefficient, and where the frictional resistance is almost constant in the C area. This is the location corresponding to the dynamic friction coefficient.
[0258]
In the actual image forming process, since the blade member 21 and the image carrier 11 are relatively moved, the friction resistance force between the cleaning blade and the glass surface is determined by the value of the friction resistance force in the C region.
[0259]
Next, the results of measuring the frictional resistance when the vibration conditions are changed by using the cleaning blade member 21 actually provided with the vibration means 23 by the above method will be described.
The measurement conditions of the surface property tester were as follows and set to a constant value.
Stage moving speed 10mm / sec
Blade load 25g / cm
Blade length 3cm (total weight is 75g)
[0260]
FIG. 15 and FIG. 16 show changes in the frictional resistance value in the C region when the bias (drive bias) applied to the piezoelectric element constituting the vibration means 23 is changed in frequency and alternating voltage (Vpp). Yes. As the value of the frictional resistance force, the value of the frictional resistance force has a value in the region C in which the stage operation is stable (in FIG. 14, from 2 seconds to 4 seconds after the start of the stage movement). did.
[0261]
First, FIG. 15 shows that when the frequency is changed when the voltage Vpp is constant, the frictional resistance decreases as the frequency increases. In FIG. 15, when the frequency is 0, no vibration is applied, that is, the condition of the conventional cleaning blade. It can be seen that the frictional resistance is reduced by exciting the piezoelectric element as compared with the conventional blade.
[0262]
Next, FIG. 16 shows a result when the voltage Vpp is changed at each of the frequencies a to e. In the figure, the magnitudes of the frequencies a to e are set to a>a>b>c>d> e.
[0263]
According to FIG. 16, it can be seen that the frictional resistance is reduced by increasing the voltage Vpp at any frequency. Although the magnitudes of these two frequencies are different at the frequencies a and b, it can be seen that the changes with respect to the voltage Vpp are almost the same.
[0264]
As described above, as a result of evaluating the frictional resistance between the blade provided with the vibration means and the glass surface using the surface property tester, it has been found that the frictional resistance is lowered by the vibration of the blade.
[0265]
As will be described later, when a blade member provided with a vibrating means is used in the image forming apparatus, the portion shown in FIG. 15 and FIG. 16 as the region where the cleaning is good is cleaned in the region where the frequency is high and the voltage Vpp is large. It can be seen that the cleaning performance is good, and that the cleaning performance is effective by reducing the frictional resistance. It is presumed that the cleaning performance is improved by reducing the frictional resistance between the blade member 21 and the image carrier 11 as compared with the conventional blade.
[0266]
Next, the relationship between the cleaning property and the frictional resistance between the blade and the image carrier in the image forming apparatus according to the present invention will be described.
Mounted with a cleaning device provided with the vibration blade according to the second invention (same as described in the embodiment of the first invention is as described above), transferability, cleaning properties and The frictional resistance between the photoconductor and the blade was evaluated and measured.
[0267]
The charging and developing conditions were as follows, and were constant during the evaluation.

[0268]
In addition, as described above, the application of the drive voltage to the piezoelectric element constituting the vibration means of the vibration blade according to the present invention amplifies the function generator for generating the pulse signal and the signal generated from the function generator. In order to confirm the voltage actually applied to the piezoelectric element through a power source, the amplified voltage was branched and monitored by an oscilloscope.
[0269]
The transfer rate was evaluated as follows.
(Evaluation of transfer rate)
In the evaluation (measurement) of the transfer rate, the operation is stopped while a solid image is being output on the surface of the image carrier, and toner images between the developing unit and the transfer unit and between the transfer cleaning unit and It was made to transfer on white paper with the Scotch tape (made by Sumitomo 3M Co., Ltd.), and it was measured with the Macbeth reflection densitometer RD514 type | mold.
[0270]
At this time,
Tape density between developer and transfer area: Ddt
Tape density between transfer part and cleaning part: Dtc
Density just transferred scotch tape on white paper: Dref
And the transfer efficiency was calculated by the following equation (1).
[0271]
[Expression 2]

[0272]
(Cleaning evaluation)
The cleaning property was also evaluated using a scotch tape in the same manner as the previous 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 (manufactured by Sumitomo 3M Co., Ltd.), and it is similarly transferred with a Macbeth reflection densitometer RD514 type. The difference between the measured value and the blank (white paper with only the scotch tape applied) was 0.01 or less, and the difference (high density) was determined to be poor.
[0273]
Actual output is 0.1mg / cm on the photoconductor ² An image pattern is prepared, and this is output for 50000 sheets in the vertical direction of A3 paper. At the stage where the output of 50,000 sheets was completed, as shown in the method for measuring the transfer rate and the cleaning rate, an image pattern that gave a solid image was output halfway and evaluated.
[0274]
Next, the frictional resistance in the image forming apparatus was estimated as follows.
A rotational torque meter was attached to the shaft of the drum-shaped image carrier 11 attached in the image forming apparatus, and the torque was measured during the rotational operation. In this measurement, the rotational torque was measured with only the cleaning blade member 21 provided with the vibration means 23 being in contact with the image carrier 11. In the evaluation of the cleaning property, as described above, the steps necessary for visualizing the charging step, the developing step, and the transfer step were incorporated. As a measuring instrument corresponding to the frictional resistance force between the blade member 21 and the image carrier 11, it is optimal to incorporate this torque meter into the image forming apparatus in that the frictional resistance force is directly examined.
[0275]
In addition, although the drum-shaped OPC is performed here, the measurement can be similarly performed on the belt-shaped photosensitive member. However, in order to clean the toner by contacting the blade, it is necessary to make contact with the photosensitive member. Therefore, it is preferable to arrange 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 for suspending the belt is often provided. The location of the torque meter is preferably attached to the shaft of the suspension roller closest to the blade.
[0276]
First, FIG. 17 shows the change in rotational torque when the drive bias voltage Vpp for the vibration means is kept constant at 20 V and the drive frequency is changed. In the same figure, when the cleaning operation is performed under the respective driving bias conditions, that is, in the above-described evaluation of the cleaning performance after the output corresponding to 50,000 sheets is performed while actually cleaning the residual toner. Also shown is the area where cleaning was possible and good.
[0277]
As can be seen from FIG. 17, with respect to the rotational torque, when the drive frequency is increased, the rotational torque decreases and shows the same tendency as shown in FIG. From the relationship with the cleaning property, it can be seen that the cleaning is possible and good at a high driving frequency. When there is no vibration, the rotational torque is large, and it is predicted that a large load is applied to the rotation of the image carrier, and the cleaning property is very poor.
[0278]
The conventional pulverized toner can be cleaned without applying vibration to the blade. However, in the case of using a nearly spherical toner for high image quality, as described in the first invention, The presence or absence of vibration greatly affects the cleaning performance.
[0279]
Next, FIG. 18 shows changes in rotational torque when the drive frequency of the drive bias for the vibration means is changed from frequencies a to e and the voltage Vpp at each frequency is changed. In the same figure, when the cleaning operation is performed under the respective driving bias conditions, that is, in the above-described evaluation of the cleaning performance after the output corresponding to 50,000 sheets is performed while actually cleaning the residual toner. Also shown is the area where cleaning was possible and good. Note that the magnitudes of the frequencies a to e are set to a relationship of a>b>c>d> e.
[0280]
As can be seen from FIG. 18, when the voltage Vpp is increased, the rotational torque decreases, and the same tendency as in FIG. 16 described above is shown. Examining the relationship with the cleaning property, it can be seen that the cleaning is possible and good at a high voltage Vpp, but the cleaning property is poor at low frequencies c to e. The voltage Vpp is 0, that is, the rotational torque can be decreased by increasing the voltage Vpp and oscillating compared to a conventional blade without an oscillating means (c, d). It can be seen that the drive bias to the element needs to vibrate at a certain frequency. At the frequency e, the rotational torque was almost the same as that of the conventional blade even when the blade was vibrated.
[0281]
From the relationship between the results of changing these drive bias conditions and the cleaning performance, it can be seen that the cleaning performance is improved by reducing the rotational torque, in other words, reducing the frictional resistance between the blade and the image carrier.
[0282]
Next, a DC motor was used as a motor for rotating the image carrier of the image forming apparatus, and the current value of the drive current for this motor was detected and measured. In this case, when the frictional resistance is low, that is, when the load on the motor is small, it is predicted that the current flowing through the DC motor will be low. Actually, as in the previous evaluation of the rotational torque meter, the experiment was performed by changing the motor for driving the drum-shaped image carrier to a DC motor, and the frequency of the drive signal for the piezoelectric element as the vibration means was changed. FIG. 19 and FIG. 20 show the results obtained and the results when the voltage Vpp is changed.
[0283]
The tendency of the change in the drive bias and the drive current of the motor is the same as the result of the conventional rotational torque, but it can be seen that the change in the voltage Vpp at each of the frequencies a to e changes linearly. Similarly, when the relationship with the cleaning property is seen, it can be seen that the cleaning property is improved when the driving current of the motor is small.
[0284]
Therefore, the method of detecting the drive current and estimating the frictional resistance based on the detection result cannot directly grasp the frictional resistance, but without a mechanical device such as a rotational torque meter. An image forming apparatus can be configured.
[0285]
Then, from the relationship between the result of changing the drive bias and the cleaning performance, the cleaning current is lowered by lowering the driving current for driving the DC motor, in other words, lowering the load between the blade and the image carrier, that is, the frictional resistance. It turns out that it improves.
[0286]
As described above, based on the detection result of the rotation torque of the image carrier or the driving current of the DC motor, the piezoelectric elements constituting the vibration means are fed back from the image forming conditions (toner consumption, environmental conditions, number of printed sheets). By controlling and changing the frictional resistance between the blade member and the image carrier, a stable and good cleaning property can be obtained.
[0287]
The evaluation of the cleaning property is difficult to judge at the beginning, and the evaluation of the cleaning property after a certain number of output sheets is necessary for the actual toner cleaning (as described above, the cleaning property after the output of 50,000 sheets is necessary in the evaluation). Is compared with this and the excitation conditions.)
[0288]
Furthermore, when image formation is performed using an actual image forming apparatus, the surface of the image carrier undergoes changes such as toner filming and photosensitive layer film scraping (this reduces the frictional resistance). It is easily guessed that this is happening in the second invention as well.) For this reason, it is considered that the optimum conditions for cleaning, in this case, the frictional resistance between the blade and the image carrier are changing.
[0289]
Therefore, it is necessary to control the vibration conditions by the vibration means by some means. As described above, it is most effective to use a piezoelectric element for that purpose. By changing the drive bias of the piezoelectric element, it is possible to lower the frictional resistance, rotational torque, and DC motor drive current. Even if these conditions change with a certain level of image output, cleaning is performed under optimum conditions. It becomes possible to do.
[0290]
Here, the index of change in the excitation condition will be described. Filming is a problem caused by the toner being stretched on the surface of the image carrier by the blade. When the toner is filmed, the frictional resistance between the blade and the image carrier may be lowered or increased depending on the type of toner. In any case, in order to ensure normal cleaning, it is necessary to maintain the minimum frictional resistance necessary for cleaning the toner.
[0291]
Toner filming tends to be promoted when the amount of consumption is high and the image area ratio is high, even though the toner consumption and output image area ratio are not completely linear. There is. The reason for this is presumed that filming is more likely to occur with the blade as the amount of toner in contact with the image carrier increases.
[0292]
Therefore, the image area ratio is calculated based on the image data, and the frictional resistance force, the rotational torque, or the drive current when using the DC motor is controlled by changing the vibration condition of the blade based on the image area ratio. In this case, it is possible to set optimum cleaning conditions. In addition, when the environmental conditions change, deformation of the blade portion with respect to the environment also changes the cleaning blade contact conditions, so that it is predicted that the frictional resistance, rotational torque, and DC motor drive current will also change. Accordingly, it is possible to perform optimum cleaning by detecting these values and setting an appropriate vibration condition according to the detection result.
[0293]
Next, the pressing amount and contact angle of the blade member 21 of the vibration blade 20 against the image carrier 11 in the first and second inventions will be described with reference to FIG. FIG. 2 is an enlarged explanatory view of a main part showing a contact state between the blade member 21 and the image carrier 11.
First, the blade member 21 is in contact with the rotation direction (arrow A direction) of the image carrier 11 in the counter direction. That is, the image carrier 11 is set to move in the direction in which the angle θ at which the blade member 21 and the image carrier 11 abut is increased.
[0294]
As a result, the cut surface 21a of the blade member 21 is not turned over, and even when a wedge shape is formed, it is possible to maintain a very small shape and prevent toner from entering the nip portion.
[0295]
The blade member 21 is pressed against the image carrier 11 at the tip of the nip portion by the above-described pressing force, and the pressing amount is d in the height direction of the blade member 21 from the surface of the image carrier 11 at this time. That is, the initial setting is a state in which the blade member 21 is pressed toward the image carrier 11 by the height of the pressing amount d from the contact position of the tip of the blade member 21. Here, the initial setting is a blade pressing amount in a state where no vibration is applied. In the vibration blade 20 using the single plate piezoelectric element as the vibration means 23, the pressing amount d is a deformation of the elastic blade nip portion. This corresponds to the amount of bending deformation of the vibration member 22 including the piezoelectric element.
[0296]
The value of the pressing amount d depends on the thickness and hardness of the blade member 21, but when the thickness is 100 to 300 μm and the hardness is JISA 75 to 100 °, the pressing amount d is in the range of 10 to 100 μm. Is preferred. When the blade member 21 is thin and hard, the pressing amount d is small. When the blade member 21 is thick and low in hardness, the pressing amount d is large.
[0297]
In addition, the contact angle θ of the blade member 21 with respect to the image carrier 11 is in the range of 0 to 50 °, so that even if the wedge shape is formed by eliminating the turning of the cut surface 21 a of the blade member 21. In addition, it is possible to maintain a small shape, prevent the toner from entering the nip portion, and obtain a cleaning performance.
[0298]
When the contact angle θ is 0 to 10 °, the length L (see FIG. 2) of the blade member 21 affixed to the vibration member 22 is shortened to 2 to 5 mm so that the image carrier 11 is actually When the length L of the blade member 21 is as long as 5 mm or more, the blade edge 21b is inclined within a range of 10 to 50 ° (see FIG. 4). It is preferable to make it the structure which contacts.
[0299]
Next, the protrusion amount of the blade member 21 with respect to the diaphragm member 22 will be described with reference to FIGS. 21 and 22 described above.
First, in the example shown in FIG. 21, the rigidity of the vibration member 22 is higher than the rigidity of the blade member 21, and the relationship between the tip protrusion amounts of the blade member 21 and the vibration member 22 is substantially the same (or the blade member 21). The tip is shorter than the vibration member 22, that is, retracted from the tip of the vibration member 22.
[0300]
By adopting such a configuration, it is possible to suppress the propagation of vibration of the vibration member 22 by the vibration means 23 from being attenuated in the nip portion, and to transmit it to the blade nip portion that directly acts on the toner cleaning at substantially the same level. And more efficient cleaning becomes possible.
[0301]
In the other example shown in FIG. 22, the vibration member 22 has a higher rigidity than the blade member 21 as before, but the tip of the blade member 21 protrudes from the tip of the vibration member 22 by the protrusion amount h. The structure of the relationship. However, a minute amount of high-frequency vibration is easily absorbed by the blade of the rubber elastic member. As a result of the experiment, in order to use a blade having a JIS hardness in the range of 80 to 100 ° and to reduce the nip displacement amount to 70% or less, the tip of the blade 21 with respect to the vibrating member 22 It has been found that the protrusion amount h should be set to be not more than twice the blade thickness.
[0302]
As a result, the propagation of vibration of the vibrating member 22 by the vibration means 23 is suppressed from being attenuated at the nip portion, and can be transmitted to the blade nip portion that directly acts on toner cleaning at substantially the same level. In addition to being able to perform good cleaning, it is possible to set the voltage and frequency within the range in which the heat generation of the piezoelectric element does not matter as the driving condition of the vibration means 23, and it becomes possible to clean spherical and small-diameter toner.
[0303]
Next, a fourth embodiment of the vibration blade 20 of the cleaning device 16 will be described with reference to FIGS.
In this embodiment, a plate-like piezoelectric element is used as the vibration means 23 as in the previous embodiment, and the vibrating member 22 is formed with a thin portion 22b in which a portion corresponding to a region where the piezoelectric element is joined is thinned. Only the part is structured to be easily elastically deformed. The blade member 21 is a urethane blade member, and the vibration member 22 has the blade member 21 bonded to the tip region, and determines the contact angle θ of the blade member 21 to the image carrier 11 and the amount of biting (pressing amount) d. The configuration is the same as the configuration of FIG.
[0304]
As a result, the rigidity of the tip region to which the blade member 21 of the vibration member 22 is attached can be increased and the natural frequency can be set high, so that the tip portion of the vibration member 22 can reach the high frequency region in the width direction of the blade member 21. It becomes possible to vibrate uniformly, and high-performance cleaning without cleaning unevenness becomes possible. Since the vibration member 22 is thinned only in the portion corresponding to the region where the piezoelectric elements are joined, the natural frequency of the entire vibration blade 20 can be maintained high, and vibration up to a high frequency is possible.
[0305]
Further, the vibration member 22 is provided with a plurality of punching regions (thickening portions) 22 d in the width direction between the plurality of vibration means 23. Thereby, the efficiency of the bending deformation of the vibration member 22 in the distal direction by the piezoelectric element (vibration means 23) is further improved, and the blade member 21 can be vibrated more efficiently.
[0306]
Here, with respect to the vibration blade 20 (cleaning blade) of this embodiment, the result of measuring the vibration displacement amount of the actual nip portion will be described with reference to FIG. 25 and FIG.
[0307]
The measurement conditions of the displacement amount of the blade nip surface shown in FIG. 25 are as follows. The width of the blade member 21 is set to A3 size lateral width, the nip portion pressing amount d to the image carrier 11 is 50 μm, and a plurality of piezoelectric elements (excitation means 23 ) Is applied with a common drive signal Pv, and the drive signal Pv has four stages of voltage 220V and frequency 10 to 40 kHz. The used piezoelectric element had a thickness of 0.3 mm and a vertical and horizontal dimension of 7 × 10 mm. The vibration displacement meter used for the measurement is an AT0021 laser Doppler vibrometer manufactured by Graphtec Corp., with a beam diameter of Φ12 μm.
[0308]
From this result, it can be seen that a substantially uniform displacement can be obtained in the width direction with the cleaning blade corresponding to the A3 width.
[0309]
FIG. 26 shows the result of measurement similar to the above, but the drive voltage of the drive signal Pv applied to the piezoelectric element is 80V. In this case as well, the displacement is lower than the above, but the performance is sufficient to reduce the frictional force when the linear velocity of the image carrier is relatively slow.
[0310]
Next, a fifth embodiment of the vibration blade 20 of the cleaning device 16 will be described with reference to FIG.
In this embodiment, a plate-like piezoelectric element is used as the vibration means 23, and two piezoelectric elements (vibration means 23) are provided on both surfaces of the vibration member 22. The two piezoelectric elements (excitation means 23) are set so as to be deformed in such a direction that one extends in the surface direction and the other contracts in the surface direction by applying a voltage.
[0311]
Thereby, the vibration member 22 can be bent with a double force, and the overall rigidity is increased, so that the natural frequency can be increased.
[0312]
Next, a sixth embodiment of the vibration blade 20 of the cleaning device 16 will be described with reference to FIG.
In this embodiment, the vibration member 32 is thickened to increase its rigidity, and a U-shaped recess 32a is formed so as to sandwich the vibration means 33 using a laminated piezoelectric element. The fourth embodiment is formed in the recess 32a. A stacked piezoelectric element that utilizes the displacement in the d33 direction similar to the form is disposed.
[0313]
And the vibration groove | channel 32c is provided and it forms so that the part 32b may become thin so that the front-end | tip part of the vibration member 32 may vibrate efficiently by the vibration means 33. FIG. The blade member 21 is thinned so that vibration from the vibration member 32 is easily transmitted.
[0314]
Thereby, the rigidity of the part to which the blade member 21 of the vibration member 32 is attached can be increased, and vibration can be propagated to the blade member 21 more efficiently.
[0315]
Next, a process cartridge according to the first invention or the second invention including the cleaning device according to the first invention or the second invention will be described with reference to FIG. 2 is a schematic sectional view of the process cartridge.
[0316]
The process cartridge 70 includes a plurality of components, such as an image carrier 71, a charging unit 72, a developing unit 74, and a cleaning device 76 according to the first or second invention, 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.
[0317]
By providing the cleaning device 76 in a detachable process cartridge, it is possible to improve maintenance and easily replace the device with another device.
[0318]
Next, a color image forming apparatus according to the first or second invention using the process cartridge according to the first or second invention will be described with reference to FIG.
This image forming apparatus is a tandem type color image forming apparatus in which the above-described process cartridges 70 of the respective colors are juxtaposed along a transfer belt (image carrier) 81 extending horizontally.
[0319]
Four process cartridges 70 are arranged for each color of yellow, magenta, cyan, and black. The developed toner on the image carrier 71 developed by each process cartridge 70 is sequentially transferred to a transfer belt 81 to which a horizontally extending transfer voltage is applied.
[0320]
In this way, yellow, magenta, cyan, and black images are formed, transferred onto the transfer belt 81 in a multiple manner, and transferred onto the transfer material 18 by the transfer means 82. The multiple toner images on the transfer material 18 are fixed by a fixing device (not shown). The process cartridge 70 has been described in the order of yellow, magenta, cyan, and black. However, the process cartridge 70 is not specified in this order, and may be arranged in any order.
[0321]
Usually, since a color image forming apparatus has a plurality of image forming units, the apparatus becomes large. In addition, when each unit such as cleaning and charging fails individually or it is time to replace it due to its life, the apparatus is complicated and it takes a lot of time to replace the unit.
[0322]
Accordingly, a small and highly durable color image forming apparatus that can be replaced by a user is provided by integrally configuring the image carrier, the charging unit, and the developing unit as a process cartridge 70. Can do.
[0323]
Further, by using the process cartridge 70 as the process cartridge according to the first aspect of the present invention, even if spherical toner is used, no defective cleaning occurs and a high-quality image can be formed.
[0324]
In the process cartridge according to the second invention, the characteristics of the color toner may change depending on the materials of various color materials. Even in this case, the friction resistance (rotational torque of the image carrier, DC motor) Can be optimized at the time of image formation, and an image forming apparatus that can maintain the cleaning property and improve the durability can be obtained.
[0325]
In the above embodiment, the same applies to the small-diameter toner described in the spherical toner. The first invention includes both the spherical toner and the small-diameter toner, and the second invention further includes Amorphous toner is also included.
[0326]
【The invention's effect】
As explained above, According to the present invention According to the image forming apparatus, toner having a circularity of 0.96 to 1.00 is used. Also Since the residual toner can be cleaned without causing a cleaning failure, a high-quality image can be formed.
[0328]
According to the present invention According to the process cartridge, a high quality image can be formed.
[0329]
According to the present invention According to other image forming apparatuses, According to the present invention Since a plurality of process cartridges are provided, a high-quality color image can be formed.
[Brief description of the drawings]
[Figure 1] Image forming apparatus according to the present invention For explaining the cleaning mechanism of
[Figure 2] In the present invention Schematic configuration diagram of the image forming apparatus
FIG. 3 is an enlarged explanatory view of a main part for explaining the first embodiment of the vibration blade of the cleaning device of the image forming apparatus.
4 is an enlarged explanatory view of the main part of FIG.
FIG. 5 is an explanatory front view of the vibration blade.
FIG. 6 is an explanatory view of the vibration blade viewed from the tip side.
FIG. 7 is an explanatory diagram illustrating an example of a drive system for the cleaning device
[Fig. 8] same Explanatory drawing with which it uses for description of 2nd Embodiment of the vibration blade of a cleaning apparatus
FIG. 9 is an explanatory diagram of the vibration blade in the width direction of the image carrier.
FIG. 10 same Explanatory drawing with which it uses for description of 3rd Embodiment of the vibration blade of a cleaning apparatus
FIG. 11 is an explanatory view of the vibration blade viewed from the tip side.
FIG. 12 is an explanatory diagram for explaining the circularity of toner.
FIG. 13 is a schematic diagram for explaining a measurement experiment regarding frictional resistance between a blade member and an image carrier.
FIG. 14 is an explanatory diagram showing an example of the same measurement result
FIG. 15 is an explanatory diagram for explaining the relationship between the frequency of the drive signal and the frictional resistance force for the vibration blade and the cleaning performance.
FIG. 16 is an explanatory diagram for explaining the frequency of the drive signal for the vibration blade, the relationship between the drive voltage and the frictional resistance, and the cleaning performance.
FIG. 17 is an explanatory diagram for explaining the relationship between the frequency of the drive signal for the vibration blade and the rotational torque of the image carrier and the cleaning performance.
FIG. 18 is an explanatory diagram for explaining the frequency of the drive signal for the vibration blade, the relationship between the drive voltage and the rotational torque of the image carrier, and the cleaning performance.
FIG. 19 is an explanatory diagram for explaining the relationship between the frequency of the drive signal for the vibration blade and the drive current of the drive motor of the image carrier and the cleaning performance.
FIG. 20 is an explanatory diagram for explaining the relationship between the frequency of the drive signal for the vibration blade, the drive voltage, the drive current of the drive motor of the image carrier, and the cleaning performance.
FIG. 21 is an explanatory diagram for explaining a contact angle and a pressing amount of a blade member.
FIG. 22 is an explanatory diagram for explaining the protrusion amount of the vibration member and the blade member.
FIG. 23 same The vibration blade of the cleaning device 4 Explanatory drawing for explanation of embodiment
FIG. 24 is an explanatory view of an image carrier width direction of the cleaning device.
FIG. 25 is an explanatory view for explaining the measurement result of the displacement amount of the blade nip portion in the cleaning device.
FIG. 26 is an explanatory diagram for explaining another measurement result of the displacement amount of the blade nip portion in the cleaning device.
FIG. 27 same The vibration blade of the cleaning device 5 Explanatory drawing for explanation of embodiment
FIG. 28 same The vibration blade of the cleaning device 6 Explanatory drawing for explanation of embodiment
FIG. 29 is an explanatory diagram for explaining a process cartridge according to the present invention.
FIG. 30 is a schematic configuration diagram of an image forming apparatus according to the present invention including a process cartridge according to the present invention.
FIG. 31 is an explanatory diagram for explaining a conventional cleaning blade.
FIG. 32 is a main part enlarged explanatory view showing a state when the image carrier of the cleaning blade is moving.
FIG. 33 is an explanatory diagram for explaining a cleaning mechanism of pulverized toner using the cleaning blade.
FIG. 34 is an explanatory diagram for explaining stick-slip motion in a cleaning mechanism of pulverized toner using the cleaning blade.
FIG. 35 is an explanatory diagram for explaining a mechanism of occurrence of defective cleaning of spherical toner using the cleaning blade.
FIG. 36 is an explanatory view for explaining 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 ... Excitation blade, 21 ... Blade member, 22 ... Vibrating member, 23 ... Excitation member, 70 ... Process cartridge.

Claims (13)

A latent image is formed on the surface of the image carrier, the latent image is developed with toner to form a toner image, and the toner remaining on the surface of the image carrier after the toner image is transferred to the transfer body In the image forming apparatus to be removed by a cleaning unit, the cleaning unit includes a blade member that comes into contact with the surface of the image carrier, one end portion is fixed, and the blade member is provided on one surface of the other end portion that is a free end portion. A plate-like vibration member attached and the other end of the vibration member attached to a surface opposite to the blade member attachment surface of the other end of the vibration member in a direction perpendicular to the blade member attachment surface An image forming apparatus, wherein the toner is cleaned by vibration of a portion of the blade member in contact with the image carrier.   2. The image forming apparatus according to claim 1, wherein the toner is a toner prepared by a polymerization method.   3. The image forming apparatus according to claim 1, wherein a surface including at least a contact portion of the blade member with the image carrier is formed of a material having a low affinity with the toner material. Image forming apparatus.   4. The image forming apparatus according to claim 1, wherein the external additive added to the outside of the toner has a low affinity with a member forming the surface of the blade member. apparatus.   5. The image forming apparatus according to claim 1, wherein an amount of vibration in a nip portion of the blade member is smaller than an average particle diameter of the toner.   6. The image forming apparatus according to claim 1, wherein a displacement amount due to vibration in a nip portion of the blade member is controllable.   7. The image forming apparatus according to claim 6, further comprising means for electrically controlling a displacement amount of the blade member.   8. The image forming apparatus according to claim 1, wherein the vibrating means is a piezoelectric element.   9. The image forming apparatus according to claim 8, further comprising means for applying an alternating voltage to the piezoelectric element.   10. The image forming apparatus according to claim 1, further comprising means for differentiating a displacement amount due to vibration of the blade member between image forming and non-image forming. .   11. The image forming apparatus according to claim 1, wherein a displacement amount due to vibration of the blade member is set to at least one of a toner adhesion amount, an image forming frequency, an environmental condition, and a toner replenishment amount on the image carrier. An image forming apparatus comprising means for changing based on the image forming apparatus. In a process cartridge including at least an image carrier and a cleaning unit, the cleaning unit includes a blade member for contacting the surface of the image carrier, and one surface of the other end which is fixed and has a free end. A plate-like vibration member to which the blade member is attached, and the vibration member attached to a surface opposite to the blade member attachment surface of the other end of the vibration member in a direction perpendicular to the blade member attachment surface. And a vibration means for vibrating the other end of the blade member, wherein the toner is cleaned by vibration of a portion of the blade member in contact with the image carrier.   An image forming apparatus for forming a color image, comprising: a plurality of process cartridges according to claim 12.

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