JP2004029531A - Method, unit, and apparatus for image formation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method which has a speed condition of a transfer member for avoiding a void of a transfer image and image elongation and speed conditions of a conveyance part and a fixing part. <P>SOLUTION: The image forming method having a rotatable image carrier 8, image forming means 17 and 16 of forming toner images on the image carrier, and a transfer member 9 which comes into contact with the surface of a transfer material, sent to between a transfer member and the image carrier, on the opposite side from the surface on the image carrier as the transfer member which transfers the toner images from the image carries to the transfer material 11 and also having the conveyance part 12 which is positioned in front of the image carrier in the conveying direction of the transfer material and conveys the transfer material in timing to the transfer of the toner images and the fixing part 13 which is positioned behind the image carrier and thermally fixes the toner images on the transfer material, is characterized in that, when the images are transferred, the speed of the transfer member 9 is 1.0 to 4.0 % faster than the peripheral speed of the image carrier 8 and the speeds of the conveyance part 12 and fixing part 13 is faster than the peripheral speed of the image carrier 8. <P>COPYRIGHT: (C)2004,JPO

Description

【００２２】
さらに、定着部１３の速度を感光体８の周速度に対し３．０％増速のまま固定しておき、レジスト部１２の速度を感光体８の周速度に対し、２．０％から５．０％まで変えたときのシミュレーション結果を図４および図５に示す。図４，５より、転写ローラ９の速度が感光体８の周速度に対して０．５％、および４．０％増速しているときに、転写材１１の接触部１０における速度がすべて感光体８の周速度に対して−３．０％から＋３．０％の範囲内に収まっているのは、レジスト部の速度が２．５％から４．５％である。画像出し実験においては、レジスト部の速度が２．５％から４．５％の間で、ただし転写ローラ９の速度が感光体８の周速度に対し１．０％から４．０％増速しているときに、転写像の中抜け、画像伸びがないことを確認した（図示せず）。
【００２３】
同様のシミュレーションおよび画像出し実験を、定着部の速度を変えても行った。感光体８の周速度に対し２．５％から３．５％範囲であれば、前記した定着部の速度が３．０％増速した場合と同様の結果を得た（図示せず）。このようにレジスト部、および定着部の速度は、感光体８の周速度に対しそれぞれ、２．５％から４．５％、２．５％から３．５％の範囲に設定することで、転写像の中抜け、画像伸びが回避される（請求項２）。
【００２４】
また、感光体８および転写ローラ９の各回転駆動源のうち少なくとも一つが、ステッピングモーターであれば、前記感光体８の周速度、あるいはまた転写ローラ９の速度の精度が向上する。ここで、図６は感光体８および転写ローラ９の各回転駆動源のうち少なくとも一つをステッピングモーターとした場合の構成例を示す図である。図６（ａ）は、ステッピングモーター２２ａを感光体８の回転駆動源とし、図中のギヤを介し感光体８を回転させる例であり、この場合には、転写ローラ９は感光体８の回転により連れ回る。また、図６（ｂ）は、感光体８の回転駆動源としてステッピングモーター２２ｂを有し、さらに転写ローラ９の回転駆動源としてステッピングモーター以外の例えばサーボ式のモーター３６ｂを用いた例になっている。あるいはまた図６（ｃ）のように、感光体８の回転駆動源としてステッピングモーター以外のモーター３６ｃを有し、さらに転写ローラ９の回転駆動源としてステッピングモーター２２ｃを用いた例であっても構わない。感光体８の周速度、あるいはまた転写ローラ９の速度精度が向上することで、請求項１，２に記載したような速度条件に対し確実に設定され、延いては転写像の中抜け、および画像伸び回避が高い信頼性の元で達成される（請求項３）。
【００２５】
ステッピングモーターを用いる他の例では、感光体８と転写ローラ９とをギヤで連結し同期させることで、一つのステッピングモーターにより、感光体８と転写ローラ９の回転精度が向上するようにしてもよい。図７は、感光体８と転写ローラ９をギヤ３７ａ，３７ｂを介して連結させ、感光体８の回転駆動源としてステッピングモーター３８を設けた構成であり、この場合、感光体８および転写ローラ９ともにステッピングモーター３８による高い精度で速度が請求項１，２に記載したような速度条件に設定され、延いては転写像の中抜け、および画像伸び回避が高い信頼性の元に達成される（請求項４）。
【００２６】
また、感光体８および転写ローラ９をそれぞれ独立のステッピングモーターにより回転駆動させても構わない。この場合、図８に示すように、二つのステッピングモーター３９ａ，３９ｂがそれぞれ感光体８および転写ローラ９の回転駆動源となる。このとき請求項４の方式よりも感光体８および転写ローラ９の速度設定が仲介しているギヤ歯数に関わりなく独立に設定でき、延いては自由度の高い、かつ高い精度の速度設定の元で、転写像の中抜け、および画像伸び回避が達成される（請求項５）。
一方レジスト部１２、および定着部１３の回転駆動源のいずれか一方、もしくはその両方をステッピングモーターにしても構わない。この場合、請求項２に記載したレジスト部１２および定着部１３の速度設定の精度が向上し、延いては転写像の中抜け、および画像伸び回避の信頼性がさらに向上する（請求項６）。
【００２７】
以上の第一実施例では、転写ローラ９の導電性弾性体層の硬度がＡＳＫＥＲ−Ｃ硬度で４２°の元で実施していた。これをＡＳＫＥＲ−Ｃ硬度で２０°から４５°まで変え、請求項１，２に記載する転写ローラ９、レジスト部１２、定着部１３の速度条件で、シミュレーションおよび画像出し実験を行ったところ、感光体８と転写ローラ９との圧接力を５０ｇ／ｃｍ^２〜４００ｇ／ｃｍ^２にする事でほぼ同様の結果を得た（図示せず）。このように、転写ローラ９の硬度がＡＳＫＥＲ−Ｃ硬度で２０°から４５°の範囲であって、かつ圧接力が５０ｇ／ｃｍ^２から４００ｇ／ｃｍ^２までの範囲である場合、請求項１，２に記載の転写ローラ９、レジスト部１２、定着部１３の速度設定のとき、転写像の中抜け、および画像伸び回避が達成される（請求項７）。
【００２８】
さらに転写ローラ９に関して言えば、転写バイアスが印加され転写が実施される。ここで、図９（ａ）〜（ｃ）は転写ローラの構成例を示す図であり、図９（ａ）に示す転写ローラ９のように、転写ローラ９の芯金４１の周囲を、フェニール系シリコンゴムの発泡性スポンジゴム材料４０で構成することにより、酸化、あるいは絶縁破壊の抑制がなされ、転写劣化寿命が延び、延いては転写像の中抜け、および画像伸び回避の高耐久化が達成される（請求項８）。
【００２９】
一方、図９（ｂ）に示す転写ローラ９は、芯金４１の周囲の層が、表面層４２ａと中層４２ｂのように二層あり、表面層４２ａが中層４２ｂよりも硬度が高く、かつ摩擦係数が１．０以上を有する構成になっている。このような転写ローラ９の構成では、表面層４２ａの高硬度によって対磨耗性が高まり、さらに、例えば中層４２ｂの硬度が、請求項７に記載の硬度を有し、かつ表面層４２ａの厚さがごく薄い場合、中層４２ａが一様に構成されている場合の請求項７に記載の画像形成方法と同等レベルが得られ、かつ高磨耗性を有する。また、表面層４２ａの厚さがある程度厚い場合でも、表面層４２ａと中層４２ｂとの合成した硬度が請求項７に記載の硬度を有すれば、請求項７に記載の画像形成方法と同等レベルが得られ、かつ高磨耗性を有する（請求項９）。上記は、芯金４１の周囲の層が二層で構成された場合を説明したが、三層以上の多層であっても構わない。
【００３０】
転写ローラ９の芯金についてさらに言えば、図９（ｃ）に示す転写ローラ９のように、芯金は、軸方向に対し一様に、芯金４１ａ（図中の白部分）と４１ｂ（図中の黒部分）の二層に分かれる構成を有し、例えば転写ローラ９の周囲が劣化した場合には、その部分のみの交換がなされる。すなわち芯金４１ａと芯金４１ｂは軸方向に稼動し、また芯金４１ｂは転写ローラ表面４３に対し接着してあるため、芯金４１ａと、芯金４１ｂに密着した転写ローラ表面４３が着脱される。さらに芯金４１ａ，４１ｂには凹凸があり、これより転写材１１の搬送に対し芯金４１ａの回転と、芯金４１ｂ延いては転写ローラ表面４３の回転は一体となって、前述の請求項１〜９に記載した画像形成方法が実施できる（請求項１０）。
【００３１】
請求項１０に記載する画像形成方法において、例えば、転写ローラ表面４３の寿命、あるいは予め設定しておいた転写ローラ表面４３の利用規定期間が経過した場合、請求項１０に記載したように芯金４１ａは共通部品として流用し、かつ芯金４１ｂと転写ローラ表面４３を一体とした部品を交換することで、芯金４１ａにおけるリユース性を備えた、前記した請求項１〜９に記載した画像形成方法が達成される（請求項１１）。
【００３２】
以上までのシミュレーションおよび画像出し実験では、図１０に示すように、レジスト部１２における転写材１１の狭持方向より感光体８側への延長方向である方向Ａと、感光体８と転写ローラ９とにおける転写材１１の狭持方向よりレジスト部１２側への延長方向である方向Ｂとの成す角度ＡＢを５０°とし、かつ方向Ｂと方向Ａの交わり部分近傍で搬送ガイド４９ａを施して実施していた。そして、角度ＡＢを変え、前記する結果と同様の結果となる角度はおよそ４０°から６０°の範囲にあった。従って、角度ＡＢは以下の範囲、
４０°≦角度ＡＢ≦６０°
に設定することが望ましい（請求項１２）。
【００３３】
さらに、このとき図１１に示すように、感光体８と転写ローラ９とにおける転写材１１の狭持方向より定着部１３への延長方向である方向Ｃと、定着部１３における転写材１１の狭持方向より感光体８側への延長方向である方向Ｄとの成す角度ＣＤを３５°とし、かつ方向Ｃと方向Ｄとの交わり部分近傍に搬送ガイド４９ｂを施して実施していた。そして、角度ＣＤを変更し、前記する結果と同様の結果となる角度は、以下の範囲となった。
３０°≦角度ＣＤ≦４０°
従って、角度ＣＤを以上の範囲に設定することが望ましい（請求項１３）。
【００３４】
請求項１に記載したように、転写材１１の速度は感光体８に対しおよそ−３．０％から＋３．０％以内であることが望ましい。このとき、前記の表１に寄れば、感光体８と転写ローラ９とにおける転写材１１の狭持位置よりレジスト部１２側近傍にある転写材１１、もしくはその一部は、感光体８と転写ローラ９とにおける転写材１１の狭持方向よりレジスト部１２側への延長上に有している（接している）。逆に転写材１１の速度が感光体８に対し−３．０％から＋３．０％以内にない場合、転写材１１もしくはその一部は、前記延長上より外れる（接していない）。
【００３５】
図１２に示すように、転写材１１の速度が感光体８の周速度より−３．０％から＋３．０％以内である場合、転写材１１は転写材１１ｂのような形状になる。ただし転写材１１ｂは、前記方向Ａおよび方向Ｂに接する形状を有する。一方、−３．０％から＋３．０％以内にない場合は、例えば転写材１１ａのような形状になる。この場合、転写材１１ａは方向Ａおよび方向Ｂに接していない。この転写材１１ａのような形状は、主にレジスト部１２の速度が請求項２に記載された速度条件範囲よりも大きい場合に生じる典型的な形状である。一枚の転写材１１の搬送中においては、多少なりとも速度変動が生じる。このため感光体８と転写ローラ９の上流近傍に、転写材１１の形状を検知する転写材たわみ量検知手段５１ａを付加し、およびこれと接続した制御手段５０ａによりレジスト部１２の速度を変えることにより、搬送状況に応じた転写材１１の速度制御をすることがより望ましい（請求項１４）。
【００３６】
さらに前記転写材たわみ量をＬとし、このＬに対し、感光体８と転写ローラ９とにおける転写材１１の狭持位置よりレジスト部側近傍にある転写材１１、もしくは転写材１１の一部が、感光体８と転写ローラ９とにおける転写材１１の狭持方向より前記搬送部側への延長上に有するときをゼロとし、かつレジスト部における転写材１１の狭持位置から感光体８と転写ローラ９とにおける転写材１１の狭持位置を結ぶ線分Ｅに対し近づくときを正値、かつ離れるときを負値とするとき、転写材たわみ量Ｌが正の場合にはレジスト部１２の速度を増加し、かつ負の場合には減少する制御手段５０ａを有することで、転写材１１の速度が常に感光体８に対し−３．０％から＋３．０％以内に制御され、延いては安定した請求項２に記載の画像形成方法が実施される（請求項１５）。尚、転写材たわみ量検知手段５１ａとしては、発光ダイオード（ＬＥＤ）あるいはレーザータイプの変位センサや、メカニカルフィラーを転写材１１面の上下に備える構成などがある。このときメカニカルフィラーは、転写材１１と接触する部分の摩擦係数は低い事が望ましい。
【００３７】
前述したように、レジスト部１２の速度に応じ前記転写材たわみ量Ｌは変化する。このとき、始めに、レジスト部１２における転写材１１の狭持位置より感光体８側近傍にある転写材１１、もしくは転写材１１の一部の形状が変化しだす。従って、図１３に示すように、転写材たわみ量検知手段５１ｂがこの部分の転写材たわみ量（これをＬ’とする）を検知し、制御手段５０ｂに送り、これによりレジスト部１２の速度を制御することで、転写材１１の速度変動に対し応答性の高い制御が実施される（請求項１６）。さらに、転写材たわみ量Ｌ’に対し、レジスト部１２における転写材１１の狭持位置より感光体８側近傍にある転写材１１、もしくは転写材１１の一部が、レジスト１２における転写材１１の狭持方向より感光体８側への延長上に有するときをゼロとし、かつ前記線分Ｅに対し近づくときを正値、かつ離れるときを負値とするとき、転写材たわみ量Ｌ’が正の場合にはレジスト部１２の速度を増加し、かつ負の場合には減少する制御手段５０ｂを有することで、転写材１１の速度が常に感光体８に対し−３．０％から＋３．０％以内に制御され、延いては安定した、かつ即応性に優れた請求項２に記載の画像形成方法が実施される（請求項１７）。
また、前記転写材たわみ量Ｌ，Ｌ’を同時に検知し、これに基づき制御手段がレジスト部１２の速度を制御しても構わない（図示せず）（請求項１８）。
【００３８】
以上に記載した第一実施例に基づく構成（図１）は、そのまま転写部材がローラである画像形成ユニットに適用される（請求項１９）。また、感光体８上の可視像（トナー像）が、複数色を有するカラー可視像であっても構わない（請求項２２）。さらに、本画像形成ユニットは、レジスト部１２、感光体８および転写ローラ９、および定着部１３が順に鉛直上方に配置されるレイアウトであっても、安定に転写像の中抜け、画像伸びの回避がなされる（図示せず）（請求項２１）。
【００３９】
［実施例２］
本発明の第二実施例を、図１４に基づいて説明する。図１４は、転写部材として、転写搬送用のベルト３０および電極ローラ３３を使用した画像形成ユニットに本発明を適用した場合の概略構成を示す図である（請求項２０）。尚、像担持体としての感光体２３の周囲には帯電器、現像器、クリーナー等が配設されているが図示を省略している。
図１４において、感光体２３は、支持ローラ３２と図示しない駆動手段によって駆動される駆動ローラ３１に懸架されて図中の矢印方向に走行するベルト３０に当接している。図示しない給紙部から給紙された転写材２６は、レジスト部２４より、感光体２３の表面の可視像（トナー像）とのタイミングが合わされて搬送され、感光体２３とベルト３０とが接触して形成される接触部（転写位置）２７を通過する。転写材２６には、接触部２７において感光体２３と反対側に配設される電極ローラ３３へ電源２８から供給される電圧によって転写バイアスが印加され、感光体２３上から転写材２６上に可視像（トナー像）が転写される。その後、可視像（トナー像）が転写された転写材２６は定着部２５に搬送され、定着部２５の一対のローラ（例えば加熱ローラと加圧ローラ）により可視像（トナー像）が転写材２６に熱定着される。一方、転写材搬送後のベルト３０はクリーニングブレード２９によりクリーニングされる。
【００４０】
本実施例の場合においても、感光体２３の周速度に対し、転写部材であるベルト３０の速度を１．０％から４．０％増速させ、かつレジスト部２４の速度を２．５％から４．５％増速させ、かつ定着部２５の速度を２．５％から３．５％増速させることで、転写像の中抜け、および画像伸びが確認できず、良好な画像が得られた（請求項２０）。尚、上記の実施例において、感光体２３上の可視像（トナー像）は、単色に限らず複数色を有するカラー可視像（カラートナー像）であっても構わない（請求項２２）。
【００４１】
［実施例３］
本発明の第三の実施例を図１５に基づいて説明する。図１５は画像形成装置の概略構成例を示す図であり、この画像形成装置は画像形成部に例えば図１４に示したような構成（請求項２０）の画像形成ユニット５２を備えており、該画像形成ユニット５２により感光体２３上に可視像（トナー像）が形成される。そして、給紙部の多段の給紙トレイのうちの一つの給紙トレイ５３から給紙され、レジスト部２４を介して搬送される記録紙等の転写材に、感光体２３上に形成された可視像（トナー像）が転写される。このとき本実施例では第二の実施例と同様に、転写材上に画像の中抜けおよび画像伸びがなく可視像（トナー像）が転写され、かつ定着部２５で定着され、排出部５４より排出されて、画像形成された転写材が生成される（請求項２３）。
尚、ここでは画像形成ユニット５２は図１４と同様の構成としたが、この他、図１に示した構成の画像形成ユニット等、請求項１９〜２２に記載のいずれの画像形成ユニットであっても構わない。
【００４２】
【発明の効果】
以上説明したように、請求項１に係る発明では、回転自在の像担持体と、この像担持体上にトナー像を形成する像形成手段と、前記像担持体から転写材へトナー像を転写する転写部材であって該転写部材と前記像担持体との間に送られた転写材の前記像担持体側の面とは反対側の面に接触する転写部材とを有するとともに、転写材搬送方向において像担持体前段に位置し前記トナー像の転写とのタイミングをとって転写材を搬送する搬送部と、同様に像担持体後段に位置し前記転写材上のトナー像を熱定着させる定着部を有する画像形成方法において、前記転写時に、前記転写部材の速度が前記像担持体の周速度よりも１．０％から４．０％速く、かつ前記搬送部および前記定着部の速度が前記像担持体の周速度よりも速いことを特徴とするので、転写に伴う異常画像である、中抜け、および画像伸びを安定して回避できる転写条件を提供できる。
【００４３】
請求項２に係る発明では、請求項１記載の画像形成方法において、前記搬送部の速度が前記像担持体周速度よりも２．５％から４．５％速く、かつ前記定着部の速度が前記像担持体周速度よりも２．５％〜３．５％速いことを特徴とするので、搬送部および定着部における速度条件範囲が明示され、設計が可能となる。また、請求項３に係る発明では、請求項１または２記載の画像形成方法において、前記像担持体および前記転写部材の各回転駆動源のうち、少なくとも一つはステッピングモーターであることを特徴とするので、像担持体もしくは転写部材の速度精度が向上し、請求項１または２に記載の作用効果の信頼性が向上する。さらに請求項４に係る発明では、請求項３記載の画像形成方法において、前記像担持体の回転駆動源がステッピングモーターであり、かつ像担持体の駆動と同期し転写部材を駆動することを特徴とするので、請求項３の作用効果に加え、一つのステッピングモーターを使い、低コストで、像担持体および転写部材の速度精度が向上し、より信頼性を高くして、転写に伴う異常画像が回避できる。
さらに請求項５に係る発明では、請求項３記載の画像形成方法において、前記像担持体および前記転写部材の各回転駆動源は、各々独立なステッピングモーターであることを特徴とするので、像担持体および転写部材に対し、それぞれ独立にステッピングモーターによる回転駆動が付与できるため、両者の速度設定が従属しなく、速度設定の自由度が増し、延いては設計マージンが向上する。
さらに請求項６に係る発明では、請求項３，４または５記載の画像形成方法において、前記搬送部、もしくは前記定着部、もしくはそれら両方の回転駆動源が、ステッピングモーターであることを特徴とするので、搬送部もしくは定着部、もしくはその両方の回転駆動源にステッピングモーターを用いるため、搬送部および定着部の速度精度が向上し、請求項２に記載の作用効果の信頼性がさらに向上する。
【００４４】
請求項７に係る発明では、請求項１〜６のいずれか一つに記載の画像形成方法において、前記転写部材の硬度がＡＳＫＥＲ−Ｃ硬度で２０°〜４５°、前記像担持体への圧接力が５０ｇ／ｃｍ^２〜４００ｇ／ｃｍ^２であることを特徴とするので、従来よりも高硬度の転写部材のための設計条件が提示され、これより耐久性に富んだ高硬度の転写部材が利用可能になり、高寿命化、高耐久化の達成が可能になる。
また、請求項８に係る発明では、請求項１〜７のいずれか一つに記載の画像形成方法において、前記転写部材の材質がフェニール系シリコンゴムの発泡性スポンジゴム材料であることを特徴とするので、転写部材に、抗酸化および抗絶縁破壊性に富んだ材質を利用するため、高寿命化、高耐久化が図れる。
さらに請求項９に係る発明では、請求項１〜８のいずれか一つに記載の画像形成方法において、前記転写部材は少なくとも二層以上の材質で構成され、かつ表面層が他層の厚さよりも薄く、かつ他層の硬度よりも高く、かつ摩擦係数が１．０以上であることを特徴とするので、転写部材において、対磨耗性の高い（一般に比較的高い硬度を有する）材質で表面層が構成されるため、対磨耗性が向上する。
さらに請求項１０に係る発明では、請求項１〜９のいずれか一つに記載の画像形成方法において、前記転写部材の芯金部分は少なくとも二層以上の構造を有し、かつ軸方向に着脱し、かつ転写材における搬送方向に対しては固定されることを特徴とするので、転写部材に対し、芯金部分を共用部品、すなわちリユース品として利用可能になる。
さらに請求項１１に係る発明では、請求項１０記載の画像形成方法において、前記転写部材を、その寿命、または規定期間ごとに交換することを特徴とするので、転写部材に対し、保守・メンテナンス体制が整い、顧客満足度の向上につながる。
【００４５】
請求項１２に係る発明では、請求項１〜１１のいずれか一つに記載の画像形成方法において、前記搬送部における転写材狭持方向より前記像担持体側への延長方向Ａと、前記像担持体と前記転写部材とにおける転写材狭持方向より前記搬送部側への延長方向Ｂとの角度ＡＢが以下の範囲にあって、
４０°≦角度ＡＢ≦６０°
かつ方向Ａと方向Ｂとの交わり部分近傍に少なくとも転写材搬送ガイドを設けることを特徴とするので、請求項１，２を満足する、搬送部から像担持体および転写部材間の設計条件が整い、実際の設計が容易に可能になる。
また、請求項１３に係る発明では、請求項１〜１２のいずれか一つに記載の画像形成方法において、前記定着部における転写材狭持方向より前記像担持体側への延長方向Ｃと、前記像担持体と前記転写部材とにおける転写材狭持方向より前記定着部側への延長方向Ｄとの角度ＣＤが以下の範囲にあって、
３０°≦角度ＣＤ≦４０°
かつ方向Ｃと方向Ｄとの交わり部分近傍に少なくとも転写材搬送ガイドを設けることを特徴とするので、請求項１，２を満足する、像担持体および転写部材から定着部間の設計条件が整い、実際の設計が容易に可能になる。
さらに請求項１４に係る発明では、請求項１〜１３のいずれか一つに記載の画像形成方法において、前記像担持体と前記転写部材とにおける転写材狭持位置より前記搬送部側近傍に少なくとも一つ転写材たわみ量検知手段を有し、かつ前記転写材たわみ量検知手段からの転写材たわみ量Ｌに応じて前記搬送部の速度を変える制御手段を有することを特徴とするので、転写材搬送中に生じる速度変動に応じ、これを除去する手段が整い、転写に伴う異常画像回避の信頼性がさらに向上する。
さらに請求項１５に係る発明では、請求項１４記載の画像形成方法において、前記転写材たわみ量Ｌを、前記像担持体と前記転写部材とにおける転写材狭持位置より前記搬送部側近傍にある前記転写材、もしくは前記転写材の一部が、前記像担持体と前記転写部材とにおける転写材狭持方向より前記搬送部側への延長上に有するときをゼロとし、かつ前記搬送部における転写材狭持位置から前記像担持体と前記転写部材とにおける転写材狭持位置を結ぶ線分Ｅに対し近づくときを正値、かつ離れるときを負値とするとき、前記転写材たわみ量Ｌが正の場合には前記搬送部の速度を増加し、かつ負の場合には減少する制御手段を有することを特徴とするので、請求項１４の作用効果において、速度変動除去手順が具体的に示され、容易に具現化できる。
【００４６】
請求項１６に係る発明では、請求項１〜１５のいずれか一つに記載の画像形成方法において、前記搬送部における転写材狭持位置より前記像担持体側近傍に少なくとも一つ転写材たわみ量検知手段を有し、かつ前記転写材たわみ量検知手段からの転写材たわみ量Ｌ’に応じて前記搬送部の速度を変える制御手段を有することを特徴とするので、請求項１４の作用効果に対し、転写材搬送中に生じる速度変動をより速く検知および除去する手段が整い、転写に伴う異常画像回避の信頼性がさらに向上する。
また、請求項１７に係る発明では、請求項１６記載の画像形成方法において、前記転写材たわみ量Ｌ’を、前記搬送部における転写材狭持位置より前記像担持体側近傍にある前記転写材、もしくは前記転写材の一部が、前記搬送部における転写材狭持方向より前記像担持体側への延長上に有するときをゼロとし、かつゼロより前記線分Ｅに対し近づくときを正値、かつ離れるときを負値とするとき、前記転写材たわみ量Ｌ’が正の場合には前記搬送部の速度を増加し、かつ負の場合には減少する制御手段を有することを特徴とするので、請求項１６の作用効果において、速度変動除去手段が具体的に示され、容易に具現化できる。
さらに請求項１８に係る発明では、請求項１４〜１７のいずれか一つに記載の画像形成方法において、前記転写材たわみ量Ｌ、および前記転写材たわみ量Ｌ’に応じて、前記搬送部の速度を変える制御手段を有することを特徴とするので、請求項１４〜１７のいずれか一つの作用効果を持ち、延いては転写に伴う異常画像回避の高信頼性が達成できる。
【００４７】
請求項１９に係る発明では、回転自在の像担持体と、この像担持体上にトナー像を形成する像形成手段と、前記像担持体から転写材へトナー像を転写する転写部材であって該転写部材と前記像担持体との間に送られた転写材の前記像担持体側の面とは反対側の面に接触する転写部材とを有するとともに、転写材搬送方向において像担持体前段に位置し前記トナー像の転写とのタイミングをとって転写材を搬送する搬送部と、同様に像担持体後段に位置し前記転写材上のトナー像を熱定着させる定着部を有する画像形成ユニットにおいて、請求項１〜１８のいずれか一つに記載の画像形成方法を用い、かつ前記転写部材は、ローラであることを特徴とするので、ローラ転写方式の画像形成ユニットの設計が容易に可能になる。
【００４８】
請求項２０に係る発明では、回転自在の像担持体と、この像担持体上にトナー像を形成する像形成手段と、前記像担持体から転写材へトナー像を転写する転写部材であって該転写部材と前記像担持体との間に送られた転写材の前記像担持体側の面とは反対側の面に接触する転写部材とを有するとともに、転写材搬送方向において像担持体前段に位置し前記トナー像の転写とのタイミングをとって転写材を搬送する搬送部と、同様に像担持体後段に位置し前記転写材上のトナー像を熱定着させる定着部を有する画像形成ユニットにおいて、請求項１〜１８のいずれか一つに記載の画像形成方法を用い、かつ前記転写部材は、前記像担持体に接触するベルトと、このベルトの像担持体側と逆側に接触するローラとを有することを特徴とするので、ベルト転写方式の画像形成ユニットの設計が容易に可能になる。
【００４９】
請求項２１に係る発明では、請求項１９または２０記載の画像形成ユニットにおいて、前記像担持体および前記転写部材は、前記搬送部よりも鉛直上方にあって、かつ前記定着部は前記像担持体および前記転写部材よりも鉛直上方にあることを特徴とするので、比較的転写材搬送における安定性が低い、搬送部から定着部までが縦搬送画像形成ユニットであっても、転写に伴う異常画像の安定した回避が達成できる。
また、請求項２２に係る発明では、請求項１９〜２１のいずれか一つに記載の画像形成ユニットを複数有することを特徴とするので、転写に伴う異常画像が回避できるカラー画像形成ユニットの設計が可能になる。
さらに請求項２３に係る発明では、像担持体上にトナー像を形成し、該トナー像を転写材に転写し定着して出力する画像形成装置において、請求項１９〜２２のいずれか一つに記載の画像形成ユニットを有することを特徴とするので、請求項１９〜２２のいずれか一つに記載の画像形成ユニットを搭載する画像形成装置の設計が可能になる。
【図面の簡単な説明】
【図１】本発明に係る画像形成方法を適用する画像形成装置（画像形成ユニット）の概略要部構成を示す図である。
【図２】本発明の一実施例における感光体と転写材とのスリップ率（実験値）を示す図である。
【図３】本発明の一実施例における感光体と転写材とのスリップ率（シミュレーション結果）を示す図である。
【図４】本発明の一実施例における感光体と転写材のスリップ率（レジスト部の速度を変えた場合のシミュレーション結果）を示す図である。
【図５】本発明の一実施例における感光体と転写材のスリップ率（レジスト部の速度を変えた場合のシミュレーション結果）を示す図である。
【図６】本発明の一実施例における感光体および転写ローラの各回転駆動源のうち少なくとも一つをステッピングモーターとした場合の構成例を示す図である。
【図７】本発明の一実施例における感光体および転写ローラのステッピングモーターによる回転駆動（感光体および転写ローラをギヤ駆動とした場合）の構成例を示す図である。
【図８】本発明の一実施例における感光体および転写ローラのステッピングモーターによる回転駆動（感光体および転写ローラ共に独立のステッピングモーター駆動とした場合）の構成例を示す図である。
【図９】本発明の一実施例における転写ローラの構成例を示す図である。
【図１０】本発明の一実施例におけるレジスト部と感光体および転写ローラのレイアウトを示す図である。
【図１１】本発明の一実施例における感光体および転写ローラと定着部のレイアウトを示す図である。
【図１２】本発明の一実施例における感光体および転写ローラ近傍に設置した紙たわみ量検知手段および制御手段の一例を示す図である。
【図１３】本発明の一実施例におけるレジスト部近傍に設置した紙たわみ量検知手段および制御手段の一例を示す図である。
【図１４】本発明の別の実施例を示す図であって、転写部材にベルトを用いた画像形成ユニットの概略要部構成図である。
【図１５】本発明が実施される画像形成装置の一例を示す概略構成図である。
【図１６】レジスト部から転写部を介して定着部に搬送される転写材の搬送過程の形状例を示す図である。
【図１７】従来の画像形成装置における転写装置およびその前後の装置の概略構成例を示す図である。
【符号の説明】
１：像担持体
２：転写部材
３：接触部
４：転写材
５：搬送部
６：定着部
７：転写装置
８：感光体（像担持体）
９：転写ローラ（転写部材）
１０：接触部
１１：転写材
１２：レジスト部
１３：定着部
１５：帯電ローラ
１６：現像器
１７：レーザー光
１８：クリーナー
１９ａ：搬送路
１９ｂ：搬送路
２０：電源
２１：低スリップ率範囲
２２ａ，２２ｂ，２２ｃ：ステッピングモーター
２３：感光体（像担持体）
２４：レジスト部
２５：定着部
２６：転写材
２７：接触部
２８：電源
２９：クリーニングブレード
３０：転写搬送用のベルト（転写部材）
３１：駆動ローラ
３２：支持ローラ
３３：電極ローラ
３６ｂ，３６ｃ：モーター
３７ａ，３７ｂ：ギヤ
３８：ステッピングモータ−
３９ａ，３９ｂ：ステッピングモータ−
４０：フィニール系シリコンゴムの発泡性スポンジゴム材の転写部材
４１，４１ａ，４１ｂ：芯金
４２ａ：表面層
４２ｂ：中層
４３：転写ローラ表面
４９ａ，４９ｂ：搬送ガイド
５０ａ，５０ｂ：制御手段
５１ａ，５１ｂ：紙たわみ量検知手段
５２：画像形成ユニット
５３：給紙トレイ
５４：排出部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming method and apparatus using an electrophotographic method such as a copying machine, a facsimile, a laser printer, and the like, and more particularly, to an image forming method characterized by a transfer material conveying method involving image forming, and an image forming method thereof. The present invention relates to an image forming unit used and an image forming apparatus having the image forming unit.
[0002]
[Prior art]
Conventionally, in an image forming apparatus using an electrophotographic method such as a copying machine, a facsimile, and a laser printer, a visible image is formed on an image carrier such as a photoconductor, and then the visible image on the image carrier is formed. Although a fixed image is formed on the transfer material by transferring and fixing it on a sheet-like transfer material such as a recording paper, as a transfer device for transferring a visible image on an image carrier to the transfer material, for example, FIG. As shown in FIG. 17, there is a type in which an image carrier 1 and a roller-type transfer member 2 are arranged in contact with a contact portion 3. That is, in FIG. 17, a visible image formed by a toner image on the surface of the image carrier 1 is transferred to the contact portion 3 between the image carrier 1 and the transfer member 2 at the transfer position by rotating the image carrier 1 in the arrow direction. Then, the image is transferred onto the transfer material 4 conveyed in a timely manner from the conveyance unit 5, and the visible image is thermally fixed on the transfer material 4 later by the fixing unit 6. In such a transfer device 7, the transfer image may drop out when the peripheral speed of the transfer member 2 is lower than the peripheral speed of the image carrier 1, or conversely, the transfer member 2 may be over the peripheral speed of the image carrier 1. , A chronic problem such as image stretching that occurs when the peripheral speed is too high has occurred.
[0003]
In order to solve such a problem, for example, in the prior art described in Japanese Patent No. 2880873, the transfer means has an ASKER-C hardness of 20 ° to 40 ° elasticity and a pressing force against the image carrier. Is 50g / cm ² ~ 200g / cm ² For the transfer member, the speed of the transfer member at the contact portion between the image carrier and the transfer member is set to be faster than the peripheral speed of the image carrier, specifically, 1.0% to 3.0%. By doing so, he aims to avoid it.
[0004]
[Problems to be solved by the invention]
As described above, in the related art described in Japanese Patent No. 2808173, the transfer image is missing when the speed of the transfer member is lower than the peripheral speed of the image carrier, or the transfer speed is higher than the peripheral speed of the image carrier. Chronic problems such as image elongation that occur when the speed of the member is too high can be avoided by setting the speed of the transfer member at the contact portion between the image carrier and the transfer member to be 1.0% to 3.0% lower than the peripheral speed of the image carrier. Avoidance by making% faster.
However, the hollowness of the transferred image and the image elongation are essentially due to the speed of the transfer material. For this reason, the speed of the image carrier, the transport unit located before and after the transfer member, and the speed of the fixing unit must be considered. I can't really decide. In addition, in the prior art, the ASKER-C hardness of the transfer member does not cover 40 ° or more in terms of increasing the durability of parts due to the reduction in environmental load, which has recently been pointed out, and the application range needs to be expanded. As described above, the above-mentioned conventional technology cannot be an essential solution or a technology in consideration of recent needs.
[0005]
The present invention has been made in view of the above problems, and has a rotatable image carrier, an image forming unit that forms a toner image on the image carrier, and a method of forming a toner image on the transfer material from the image carrier. A transfer member for transferring, the transfer member being provided between the transfer member and the image carrier, the transfer member being in contact with a surface of the transfer material opposite to the surface on the image carrier side; A transport unit that is located in the front of the image carrier in the direction and transports the transfer material at the timing of the transfer of the toner image, and is also located in the rear of the image carrier and thermally fixes the toner image on the transfer material. In the image forming method having a transfer portion, the transfer image includes a speed condition of a transfer member for avoiding a hollow image, and an image elongation, and a speed condition of a conveyance portion and a fixing portion, and a transfer member for realizing this. Providing an image forming method having a configuration Are intended for purposes of Rukoto, further it is an object to provide an image forming unit and an image forming apparatus using the image forming method.
[0006]
[Means for Solving the Problems]
As means for achieving the above object, the invention according to claim 1 includes a rotatable image carrier, an image forming means for forming a toner image on the image carrier, and a method for transferring the image from the image carrier to a transfer material. A transfer member that transfers a toner image, the transfer member having a transfer member that is in contact with a surface opposite to the image carrier side of the transfer material sent between the transfer member and the image carrier, A transport section that is located at the preceding stage of the image carrier in the transfer material transport direction and transports the transfer material at the timing of the transfer of the toner image; similarly, the transport section that is located at the later stage of the image carrier and heats the toner image on the transfer material. In the image forming method having a fixing unit for fixing, at the time of the transfer, the speed of the transfer member is 1.0% to 4.0% faster than the peripheral speed of the image carrier, and the transfer unit and the fixing unit are fixed. Speed is faster than the peripheral speed of the image carrier. The features.
[0007]
According to a second aspect of the present invention, in the image forming method according to the first aspect, the speed of the transport unit is 2.5% to 4.5% faster than the peripheral speed of the image carrier, and the speed of the fixing unit is higher. It is characterized in that it is 2.5% to 3.5% faster than the peripheral speed of the image carrier.
According to a third aspect of the present invention, in the image forming method according to the first or second aspect, at least one of the rotation driving sources of the image carrier and the transfer member is a stepping motor. I do.
According to a fourth aspect of the present invention, in the image forming method according to the third aspect, the rotation driving source of the image carrier is a stepping motor, and the transfer member is driven in synchronization with the driving of the image carrier. And
According to a fifth aspect of the present invention, in the image forming method of the third aspect, each of the rotation driving sources of the image carrier and the transfer member is an independent stepping motor.
According to a sixth aspect of the present invention, in the image forming method of the third, fourth or fifth aspect, the transport unit, the fixing unit, or both of them are stepping motors. .
[0008]
According to a seventh aspect of the present invention, in the image forming method according to any one of the first to sixth aspects, the hardness of the transfer member is 20 ° to 45 ° in ASKER-C hardness, and the transfer member is pressed against the image carrier. Force 50g / cm ² ~ 400g / cm ² It is characterized by being. The invention according to claim 8 is the image forming method according to any one of claims 1 to 7, wherein the material of the transfer member is a foamable sponge rubber material of phenyl silicone rubber. I do.
According to a ninth aspect of the present invention, in the image forming method according to any one of the first to eighth aspects, the transfer member is made of at least two or more layers of material, and the surface layer has a thickness smaller than that of another layer. Characterized by being thinner, higher in hardness than the other layers, and having a coefficient of friction of 1.0 or more.
According to a tenth aspect of the present invention, in the image forming method according to any one of the first to ninth aspects, the core portion of the transfer member has a structure of at least two layers and is detachable in the axial direction. And is fixed in the transport direction of the transfer material.
Further, according to an eleventh aspect of the present invention, in the image forming method according to the tenth aspect, the transfer member is replaced every service life thereof or every specified period.
[0009]
According to a twelfth aspect of the present invention, in the image forming method according to any one of the first to eleventh aspects, an extension direction A from the holding direction of the transfer material to the image carrier side in the transport unit and the image carrier The angle AB between the body and the transfer member in the direction of extension B from the transfer material holding direction to the transport unit side in the following range,
40 ° ≤ angle AB ≤ 60 °
In addition, at least a transfer material transport guide is provided near the intersection of the direction A and the direction B.
According to a thirteenth aspect of the present invention, in the image forming method according to any one of the first to twelfth aspects, an extension direction C from the holding direction of the transfer material in the fixing unit to the image carrier side, The angle CD between the image carrier and the transfer member and the direction of extension D from the transfer material holding direction to the fixing unit side is in the following range,
30 ° ≦ angle CD ≦ 40 °
In addition, at least a transfer material transport guide is provided near the intersection of the direction C and the direction D.
According to a fourteenth aspect of the present invention, in the image forming method according to any one of the first to thirteenth aspects, at least a portion of the image carrier and the transfer member that is closer to the transport unit than a transfer material holding position between the image carrier and the transfer member. One transfer material deflection amount detecting means is provided, and a control means for changing the speed of the transport unit in accordance with the transfer material deflection amount L from the transfer material deflection amount detection means is provided.
According to a fifteenth aspect of the present invention, in the image forming method according to the fourteenth aspect, the transfer material deflection amount L is closer to the transport unit than a transfer material holding position between the image carrier and the transfer member. The transfer material, or a part of the transfer material, is set to zero when the transfer material or the transfer member has an extension on the transfer member side from the transfer material holding direction in the image carrier and the transfer member, and the transfer in the transfer portion is performed. When the distance from the material holding position to a line E connecting the transfer material holding position between the image carrier and the transfer member approaches a positive value, and the distance from the material is a negative value, the transfer material deflection amount L Control means is provided for increasing the speed of the transport unit when the value is positive and decreasing the speed when the value is negative.
[0010]
According to a sixteenth aspect of the present invention, in the image forming method according to any one of the first to fifteenth aspects, at least one transfer material deflection amount is detected closer to the image carrier than a transfer material holding position in the transport unit. And a control means for changing the speed of the transport section in accordance with the transfer material deflection amount L 'from the transfer material deflection amount detection means.
According to a seventeenth aspect of the present invention, in the image forming method according to the sixteenth aspect, the transfer material deflection amount L ′ is closer to the image carrier side than the transfer material holding position in the transport unit. Or, when a part of the transfer material has an extension on the image carrier side from the transfer material holding direction in the transport unit, the value is zero, and a positive value when approaching the line segment E from zero, and When the moving distance is set to a negative value, a control means for increasing the speed of the transport unit when the transfer material deflection amount L 'is positive and decreasing the speed when the transfer material deflection amount L' is negative is provided.
According to an eighteenth aspect of the present invention, in the image forming method according to any one of the fourteenth to seventeenth aspects, according to the transfer material deflection amount L and the transfer material deflection amount L ′, It has a control means for changing the speed.
[0011]
The invention according to claim 19 is a rotatable image carrier, image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material. A transfer member that is in contact with a surface of the transfer material sent between the transfer member and the image carrier opposite to the surface on the image carrier side, and at a stage preceding the image carrier in the transfer material transport direction. An image forming unit having a transport unit that transports the transfer material at a timing that is located at the timing of transferring the toner image, and a fixing unit that is similarly located at the subsequent stage of the image carrier and thermally fixes the toner image on the transfer material. An image forming method according to any one of claims 1 to 18, wherein the transfer member is a roller.
[0012]
The invention according to claim 20 is a rotatable image carrier, image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material. A transfer member that is in contact with a surface of the transfer material sent between the transfer member and the image carrier opposite to the surface on the image carrier side, and at a stage preceding the image carrier in the transfer material transport direction. An image forming unit having a transport unit that transports the transfer material at a timing that is located at the timing of transferring the toner image, and a fixing unit that is similarly located at the subsequent stage of the image carrier and thermally fixes the toner image on the transfer material. The image forming method according to any one of claims 1 to 18, wherein the transfer member includes a belt that contacts the image carrier, and a roller that contacts the belt opposite to the image carrier side of the belt. It is characterized by having.
[0013]
The invention according to claim 21 is the image forming unit according to claim 19 or 20, wherein the image carrier and the transfer member are vertically above the transport section, and the fixing section is the image carrier. And vertically above the transfer member.
According to a twenty-second aspect of the present invention, there is provided the image forming unit according to any one of the nineteenth to twenty-first aspects.
According to a twenty-third aspect of the present invention, there is provided an image forming apparatus for forming a toner image on an image carrier, transferring the toner image to a transfer material, fixing and outputting the toner image. An image forming unit according to any one of the preceding claims.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration, operation, and operation of the present invention will be described in detail with reference to the drawings.
[0015]
[Example 1]
First Embodiment A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus to which an image forming method according to the present invention is applied. In FIG. 1, reference numeral 8 denotes a photoreceptor as an image carrier. The photoreceptor 8 includes a photosensitive layer, and is rotated in a direction indicated by an arrow in FIG. The photoreceptor 8 is charged by a charging roller 15 connected to a power supply 20 which is an example of a charging unit, and is then charged by an optical writing device (not shown) (for example, a laser light source, a laser deflector, and a laser scanning optical system including an image forming optical system). The image-modulated laser light 17 from the optical writing device using the device is projected to form an electrostatic latent image on the surface. The electrostatic latent image is visualized by a toner (not shown) in a developing unit 16 with the rotation of the photoconductor 8, and a contact portion 10 with a transfer roller 9 as a transfer member, that is, a transfer is performed. Move to position. On the other hand, a transfer material 11 such as a recording sheet fed from a paper feed unit (not shown) to the registration unit 12 in accordance with the image formation is conveyed from the registration unit 12 to the transfer position through the conveyance path 19a at a proper timing. Then, a transfer bias, which is a DC voltage having a polarity opposite to that of the toner, is applied to the transfer roller 9 from the power supply 20, and the visible image (toner image) on the photoconductor 8 is transferred onto the transfer material 11. Thereafter, the transfer material 11 is transported to the fixing unit 13 through the transport path 19b, and heated and pressed by a pair of rollers (for example, a heating roller and a pressure roller) of the fixing unit 13 to transfer a visible image (toner image). It is fixed to the material 11. Further, the toner remaining on the photoreceptor 8 is scraped off by the cleaner 18 to prepare for the subsequent image formation.
[0016]
Here, the transfer roller 9 as a transfer member has a structure in which a conductive elastic layer is provided on the outer periphery of a core bar, and the core bar is biased by a biasing means such as a spring at the longitudinal end of the transfer roller 9. It is urged toward the photoconductor 8. Also, foamed EPDM rubber is used as the material of the conductive elastic layer. The hardness of this conductive elastic body layer is 42 ° in ASKER-C hardness, and the pressing force against the photoreceptor 8 is 320 g / cm. ² And However, the pressing force here corresponds to a pressure obtained by dividing the load applied to the transfer roller 9 by the area of the contact portion 10.
[0017]
1, the peripheral speed of the photoconductor 8 is increased by 110.3 mm / s, the speed of the resist unit 12 is increased by 3.5% with respect to the peripheral speed of the photoconductor 8, and the fixing unit is fixed. The speed of the transfer roller 9 is increased by 0.5%, 4.0%, and 7.5 with respect to the peripheral speed of the photoconductor 8 by increasing the speed of the photoconductor 13 by 3.0% with respect to the peripheral speed of the photoconductor 8. %, The transfer material was divided by a finite element and a transfer simulation from the resist unit 12 to the fixing unit 13 was performed, and the other was actually an image output experiment (in the experiment, a transfer roller was used). 9 was shaken more than the simulation). In the former case, the speed of the transfer material 11 and the shape of the transfer material 11 were confirmed, and in the latter case, the void in the transferred image and the image elongation were evaluated. In particular, in the former case, the calculation is made in consideration of the individual slip characteristics of the respective rollers of the registration unit 12, the photoconductor 8, the transfer roller 9, and the fixing unit 13 with respect to the transfer material 11. The individual slip characteristics are obtained by measuring the relative error of the speed of the transfer material 11 with respect to the peripheral speed of the single roller by holding the transfer material 11 with a single roller and applying a conveyance resistance to the transfer material 11 ( Not shown). Note that this relative error is defined as a slip ratio, and hereinafter, the term "slip ratio" is used exclusively.
[0018]
FIG. 2 shows the slip characteristic of the photoconductor 8. In FIG. 2, the horizontal axis indicates a value obtained by dividing the conveyance resistance applied to the transfer material 11 by the pressing force, and the vertical axis indicates the slip ratio of the speed of the transfer material 11 to the peripheral speed of the photoconductor 8. However, in FIG. 2, the values on the horizontal axis and the vertical axis both indicate negative values. That is, when a force that promotes the transfer of the transfer material 11 is applied to the transfer of the transfer material 11, the speed of the transfer material 11 decreases. 3 shows the slip ratio characteristics when the peripheral speed is higher than the peripheral speed. Although not shown in FIG. 2, when the horizontal axis is positive, that is, when the conveyance resistance acts on the transfer material 11, the slip ratio becomes a positive value, and therefore, the speed of the transfer material 11 is reduced. It becomes slower than the peripheral speed. At this time, the negative side and the positive side of the slip ratio are drawn as point symmetrical shapes with the origin at the center. According to FIG. 2, the slip ratio monotonically changes from approximately −3.0% to (not shown in FIG. 2) + 3.0% (low slip ratio range 21), but −3.0% or less, or When the value is + 3.0% or more, a sharp change in the slip ratio is exhibited. In the latter rapid change of the slip ratio, a large image elongation may be caused on the image. Therefore, from FIG. 2, the transfer material 11 is conveyed so that the slip ratio is kept between -3.0% and + 3.0%. It is necessary to suppress resistance (including positive and negative).
[0019]
FIG. 3 shows the simulation results. FIG. 3 shows the speed of the transfer material 11 at the contact portion 10, which is expressed as a slip ratio with the photoconductor 8. The horizontal axis of the graph shown in FIG. 3 is sequentially shown at three representative times in the course of the passage of the contact portion 10 from the leading end to the trailing end of the transfer material 11. The vertical axis of the graph, that is, the slip ratio is all negative, that is, higher than the peripheral speed of the photoconductor 8. According to FIG. 3, when the speed of the transfer roller 9 is increased by 0.5% and 4.0% with respect to the peripheral speed of the photoconductor 8, the speed of the transfer material 11 gradually increases at the contact portion 10, and In addition, the slip ratio is within the range of -3.0% to + 3.0% in all the courses. (If the speed of the transfer material 11 is increased by 4.0% with respect to the peripheral speed of the photoconductor 8, Barely-about 3.0%). At this time, the shape of the transfer material 11 is, as shown in FIG. 16, substantially at a position 57 immediately upstream of the photoconductor 8 and the transfer roller 9 in a direction in which the transfer material 11 is sandwiched between the photoconductor 8 and the transfer roller 9. And at the same time, at a position 56 immediately downstream of the resist section 12, substantially along the direction in which the transfer material 11 is held in the resist section 12. When the speed of the transfer roller 9 is increased by 7.5% with respect to the peripheral speed of the photoconductor 8, the slip ratio of the transfer material 11 is about -4.0% to -5.0%. Movement is occurring. In the image output experiment results, image elongation was confirmed when the speed of the transfer roller 9 was increased by 7.5% with respect to the peripheral speed of the photoreceptor 8, and when the speed was 1.0% or less, the image was missing. Was confirmed.
[0020]
Table 1 below summarizes the results of the above simulations and image output experiments. According to Table 1, the speed range of the transfer roller 9 in which there is no image dropout and no image expansion is a case where the peripheral speed of the photoconductor 8 is increased by 1.0% to 4.0%. The case where both the speeds of the resist unit 12 and the fixing unit 13 are lower than the peripheral speed of the photoconductor 8 was performed (the speed of the resist unit 12 was reduced by 3.5%, and the speed of the fixing unit 13 was reduced by 2.5%). % Deceleration), the speed of the transfer material 11 is not within ± 3.0% of the speed of the photoconductor 8 in the simulation with respect to the speeds of the three patterns of the transfer roller 9, and the image is stretched in the image output experiment. Were observed (not shown). As described above, the speed of the transfer roller 9 is increased from 1.0% to 4.0% with respect to the peripheral speed of the photoconductor 8, and the speed of the transport unit and the fixing unit is set to the peripheral speed of the photoconductor 8. By increasing the speed more than the above, it is possible to avoid image dropout and image expansion (claim 1).
[0021]
[Table 1]

[0022]
Further, the speed of the fixing unit 13 is fixed at 3.0% higher than the peripheral speed of the photoconductor 8, and the speed of the resist unit 12 is 2.0% to 5% higher than the peripheral speed of the photoconductor 8. FIGS. 4 and 5 show the simulation results when changing to 0.0%. 4 and 5, when the speed of the transfer roller 9 is increased by 0.5% and 4.0% with respect to the peripheral speed of the photoreceptor 8, the speed of the transfer material 11 at the contact portion 10 is all increased. The peripheral speed of the photoconductor 8 falls within the range of -3.0% to + 3.0% when the speed of the resist portion is 2.5% to 4.5%. In the image output experiment, the speed of the resist portion was between 2.5% and 4.5%, but the speed of the transfer roller 9 was increased by 1.0% to 4.0% with respect to the peripheral speed of the photoconductor 8. During the operation, it was confirmed that there was no void in the transferred image and no image expansion (not shown).
[0023]
Similar simulations and image output experiments were performed even when the speed of the fixing unit was changed. When the peripheral speed of the photosensitive member 8 was in the range of 2.5% to 3.5%, the same result as that when the speed of the fixing unit was increased by 3.0% was obtained (not shown). As described above, the speeds of the resist unit and the fixing unit are set in the range of 2.5% to 4.5% and 2.5% to 3.5% with respect to the peripheral speed of the photoconductor 8, respectively. It is possible to avoid a hollow image and an image expansion in a transferred image (claim 2).
[0024]
If at least one of the rotation driving sources of the photoconductor 8 and the transfer roller 9 is a stepping motor, the accuracy of the peripheral speed of the photoconductor 8 or the speed of the transfer roller 9 is improved. Here, FIG. 6 is a diagram showing a configuration example in which at least one of the rotation driving sources of the photoconductor 8 and the transfer roller 9 is a stepping motor. FIG. 6A shows an example in which the stepping motor 22a is used as a rotation drive source of the photoconductor 8 and the photoconductor 8 is rotated via a gear in the drawing. In this case, the transfer roller 9 rotates the photoconductor 8 Take me around. FIG. 6B shows an example in which a stepping motor 22 b is used as a rotation driving source of the photoconductor 8, and a servo-type motor 36 b other than the stepping motor is used as a rotation driving source of the transfer roller 9. I have. Alternatively, as shown in FIG. 6C, an example may be used in which a motor 36c other than the stepping motor is provided as the rotation drive source of the photoconductor 8 and the stepping motor 22c is used as the rotation drive source of the transfer roller 9. Absent. By improving the peripheral speed of the photoreceptor 8 or the speed accuracy of the transfer roller 9, the speed condition is reliably set to the speed condition as described in claim 1 or 2, and furthermore, a hollow image in a transferred image, and The image stretch avoidance is achieved with high reliability (claim 3).
[0025]
In another example using a stepping motor, the rotation accuracy of the photoconductor 8 and the transfer roller 9 can be improved by connecting the photoconductor 8 and the transfer roller 9 with gears and synchronizing them by one stepping motor. Good. FIG. 7 shows a configuration in which the photoconductor 8 and the transfer roller 9 are connected via gears 37a and 37b and a stepping motor 38 is provided as a rotation drive source of the photoconductor 8. In this case, the photoconductor 8 and the transfer roller 9 are used. In both cases, the speed is set with high accuracy by the stepping motor 38 to the speed conditions as described in the first and second aspects, so that the center defect of the transferred image and the avoidance of the image elongation are achieved with high reliability. Claim 4).
[0026]
Further, the photoconductor 8 and the transfer roller 9 may be driven to rotate by independent stepping motors. In this case, as shown in FIG. 8, two stepping motors 39a and 39b serve as rotation driving sources for the photoconductor 8 and the transfer roller 9, respectively. At this time, the speed setting of the photosensitive member 8 and the transfer roller 9 can be set independently of the number of gear teeth which are mediated by the method of the fourth aspect, and thus the speed setting with a high degree of freedom and high accuracy can be achieved. In this way, it is possible to avoid a hollow image in the transferred image and to avoid the image expansion (claim 5).
On the other hand, one or both of the rotation drive sources of the registration unit 12 and the fixing unit 13 may be a stepping motor. In this case, the accuracy of the speed setting of the registration unit 12 and the fixing unit 13 described in claim 2 is improved, and furthermore, the reliability of avoiding a hollow image in a transferred image and avoiding image elongation is further improved (claim 6). .
[0027]
In the first embodiment, the hardness of the conductive elastic layer of the transfer roller 9 is set to ASKER-C hardness of 42 °. This was changed from 20 ° to 45 ° in ASKER-C hardness, and simulations and image output experiments were performed under the speed conditions of the transfer roller 9, the registration unit 12, and the fixing unit 13 according to claim 1 and 2, and Pressing force between the body 8 and the transfer roller 9 is 50 g / cm. ² ~ 400g / cm ² , Almost the same result was obtained (not shown). Thus, the hardness of the transfer roller 9 is in the range of 20 ° to 45 ° in ASKER-C hardness, and the pressing force is 50 g / cm. ² To 400g / cm ² In the case where the transfer roller 9, the registration unit 12, and the fixing unit 13 are set to the speeds according to the first and second aspects, it is possible to achieve the omission of the transferred image and the avoidance of the image elongation (claim 7). ).
[0028]
Further, regarding the transfer roller 9, a transfer bias is applied and transfer is performed. Here, FIGS. 9A to 9C are diagrams illustrating a configuration example of the transfer roller, and like the transfer roller 9 shown in FIG. By using the foamable sponge rubber material 40 made of a silicone rubber, oxidation or dielectric breakdown is suppressed, the transfer deterioration life is prolonged, and the durability of the transferred image is reduced and the image is prevented from being stretched. Is achieved (claim 8).
[0029]
On the other hand, the transfer roller 9 shown in FIG. 9B has two layers around the cored bar 41, such as a surface layer 42a and an intermediate layer 42b. The surface layer 42a has a higher hardness than the intermediate layer 42b, The configuration is such that the coefficient has 1.0 or more. With such a configuration of the transfer roller 9, the high hardness of the surface layer 42 a enhances abrasion resistance, and further, for example, the hardness of the middle layer 42 b has the hardness according to claim 7 and the thickness of the surface layer 42 a. When the thickness is extremely thin, the same level as that of the image forming method according to claim 7 in which the middle layer 42a is formed uniformly is obtained, and the abrasion resistance is high. Further, even when the surface layer 42a is thick to some extent, if the combined hardness of the surface layer 42a and the middle layer 42b has the hardness described in claim 7, the same level as the image forming method in claim 7 is attained. Is obtained and has high abrasion properties (Claim 9). In the above description, the case where the layer around the cored bar 41 is composed of two layers has been described, but a multilayer structure of three or more layers may be used.
[0030]
More specifically, regarding the core of the transfer roller 9, like the transfer roller 9 shown in FIG. 9C, the core is uniformly distributed in the axial direction with the cores 41 a (white portions in the figure) and 41 b ( (A black portion in the figure). When, for example, the periphery of the transfer roller 9 is deteriorated, only that portion is replaced. That is, since the metal core 41a and the metal core 41b operate in the axial direction and the metal core 41b is adhered to the transfer roller surface 43, the metal core 41a and the transfer roller surface 43 which is in close contact with the metal core 41b are detached. You. Furthermore, the cores 41a and 41b have irregularities, so that the rotation of the core 41a and the rotation of the core 43b and thus the surface of the transfer roller 43 for the transfer of the transfer material 11 are integrated with each other. The image forming methods described in 1 to 9 can be implemented (claim 10).
[0031]
In the image forming method according to claim 10, for example, when the life of the transfer roller surface 43 or a predetermined use period of the transfer roller surface 43 has elapsed, the core metal as described in claim 10. The image forming apparatus according to any one of claims 1 to 9, wherein the core 41a is reused as a common component, and the core 41b is replaced with a component integrating the transfer roller surface 43, thereby providing reusability in the core 41a. A method is achieved (claim 11).
[0032]
In the above-described simulation and image output experiment, as shown in FIG. 10, the direction A, which is the direction in which the transfer material 11 extends in the resist portion 12 from the holding direction of the transfer material 11 to the photoconductor 8 side, the photoconductor 8 and the transfer roller 9 In this case, the angle AB formed by the direction B, which is the direction in which the transfer material 11 extends from the holding direction of the transfer material 11 to the resist portion 12 side, is set to 50 °, and the conveyance guide 49a is provided near the intersection of the direction B and the direction A. Was. Then, by changing the angle AB, the angle that achieves the same result as that described above was in the range of about 40 ° to 60 °. Therefore, the angle AB is in the following range:
40 ° ≤ angle AB ≤ 60 °
It is desirable to set to (claim 12).
[0033]
Further, at this time, as shown in FIG. 11, a direction C which is an extending direction of the transfer material 11 between the photoconductor 8 and the transfer roller 9 from the holding direction of the transfer material 11 to the fixing unit 13, and a narrowing of the transfer material 11 in the fixing unit 13. The angle CD between the holding direction and the direction D, which is an extension direction from the holding direction to the photoconductor 8, is set to 35 °, and the conveyance guide 49b is provided near the intersection of the direction C and the direction D. Then, the angle at which the angle CD was changed and a result similar to the result described above was obtained was within the following range.
30 ° ≦ angle CD ≦ 40 °
Therefore, it is desirable to set the angle CD in the above range (claim 13).
[0034]
As described in the first aspect, it is desirable that the speed of the transfer material 11 be within a range of about −3.0% to + 3.0% with respect to the photoconductor 8. At this time, according to Table 1, the transfer material 11 located in the vicinity of the registration unit 12 from the sandwiched position of the transfer material 11 between the photosensitive member 8 and the transfer roller 9 or a part thereof is transferred to the photosensitive member 8. The transfer material 11 is provided (extended) in the direction from the holding direction of the transfer material 11 to the registration portion 12 side with respect to the roller 9. Conversely, when the speed of the transfer material 11 is not within the range of -3.0% to + 3.0% with respect to the photoconductor 8, the transfer material 11 or a part thereof is disengaged from the extension (not in contact with).
[0035]
As shown in FIG. 12, when the speed of the transfer material 11 is within −3.0% to + 3.0% of the peripheral speed of the photoconductor 8, the transfer material 11 has a shape like the transfer material 11b. However, the transfer material 11b has a shape in contact with the directions A and B. On the other hand, when it is not within the range of -3.0% to + 3.0%, the shape becomes, for example, the transfer material 11a. In this case, the transfer material 11a is not in contact with the directions A and B. The shape of the transfer material 11a is a typical shape mainly generated when the speed of the resist portion 12 is higher than the speed condition range described in claim 2. During the conveyance of one transfer material 11, the speed fluctuates to some extent. For this reason, a transfer material deflection amount detection means 51a for detecting the shape of the transfer material 11 is added near the upstream of the photoconductor 8 and the transfer roller 9, and the speed of the resist section 12 is changed by a control means 50a connected thereto. Therefore, it is more desirable to control the speed of the transfer material 11 according to the transport condition (claim 14).
[0036]
Further, the amount of deflection of the transfer material is defined as L, and the transfer material 11 or a part of the transfer material 11 which is closer to the resist portion than the holding position of the transfer material 11 between the photosensitive member 8 and the transfer roller 9 is defined as L. The time when the transfer material 11 is extended from the direction in which the transfer material 11 is sandwiched between the photosensitive member 8 and the transfer roller 9 toward the transport unit is set to zero, and the transfer between the photosensitive material 8 and the transfer portion 11 is performed in the registration portion. When the distance to the line E connecting the holding position of the transfer material 11 with the roller 9 is set to a positive value and the distance to the separation is set to a negative value, the speed of the registration unit 12 is set when the transfer material deflection amount L is positive. Is increased, and the control means 50a is decreased in the case of a negative value, so that the speed of the transfer material 11 is always controlled within a range of -3.0% to + 3.0% with respect to the photosensitive member 8, and The image forming method according to claim 2, which is stable. There is performed (claim 15). The transfer material deflection amount detecting means 51a may be a light emitting diode (LED) or a laser type displacement sensor, or may be provided with a mechanical filler above and below the transfer material 11 surface. At this time, it is desirable that the mechanical filler has a low coefficient of friction at a portion that comes into contact with the transfer material 11.
[0037]
As described above, the transfer material deflection amount L changes according to the speed of the resist unit 12. At this time, first, the shape of the transfer material 11 or a part of the transfer material 11 near the photoconductor 8 side from the holding position of the transfer material 11 in the resist unit 12 starts to change. Therefore, as shown in FIG. 13, the transfer material deflection amount detection means 51b detects the transfer material deflection amount (this is L ′) in this portion and sends it to the control means 50b, whereby the speed of the registration unit 12 is reduced. By performing the control, the control with high response to the speed fluctuation of the transfer material 11 is performed (claim 16). Further, with respect to the transfer material deflection amount L ′, the transfer material 11 or a part of the transfer material 11 that is closer to the photoconductor 8 than the holding position of the transfer material 11 in the resist unit 12 becomes less than the transfer material 11 in the resist 12. The transfer material deflection amount L ′ is positive when it is zero when it extends on the photoconductor 8 side from the holding direction, when it is close to the line segment E, and when it is away from it, it is negative. In the case of (1), the speed of the transfer material 11 is always -3.0% to +3.0 with respect to the photosensitive member 8 by having the control means 50b which increases the speed of the resist section 12 and decreases the speed in the case of negative. % Is controlled, and furthermore, the image forming method according to claim 2 which is stable and excellent in responsiveness is implemented (claim 17).
Further, the transfer material deflection amounts L and L 'may be detected at the same time, and the control means may control the speed of the resist unit 12 based on the detection (not shown).
[0038]
The configuration (FIG. 1) based on the first embodiment described above is applied to an image forming unit in which a transfer member is a roller as it is (Claim 19). Further, the visible image (toner image) on the photoconductor 8 may be a color visible image having a plurality of colors (claim 22). Further, even if the present image forming unit has a layout in which the registration unit 12, the photoconductor 8 and the transfer roller 9, and the fixing unit 13 are sequentially arranged vertically above, it is possible to stably avoid a defect in a transferred image and avoid image expansion. (Not shown) (claim 21).
[0039]
[Example 2]
A second embodiment of the present invention will be described with reference to FIG. FIG. 14 is a diagram showing a schematic configuration in a case where the present invention is applied to an image forming unit using a transfer / conveying belt 30 and an electrode roller 33 as a transfer member (claim 20). A charger, a developing device, a cleaner, and the like are arranged around the photoconductor 23 as an image carrier, but are not shown.
In FIG. 14, the photoconductor 23 is in contact with a belt 30 suspended in a direction indicated by an arrow in the figure by being suspended by a supporting roller 32 and a driving roller 31 driven by a driving unit (not shown). The transfer material 26 supplied from a paper supply unit (not shown) is conveyed from the registration unit 24 in synchronization with the timing of the visible image (toner image) on the surface of the photoconductor 23, and the photoconductor 23 and the belt 30 are conveyed. It passes through a contact portion (transfer position) 27 formed by contact. A transfer bias is applied to the transfer material 26 by a voltage supplied from a power supply 28 to the electrode roller 33 disposed on the opposite side of the contact portion 27 from the photoconductor 23, and the transfer bias is applied from the photoconductor 23 to the transfer material 26. A visual image (toner image) is transferred. Thereafter, the transfer material 26 onto which the visible image (toner image) has been transferred is conveyed to the fixing unit 25, and the visible image (toner image) is transferred by a pair of rollers (for example, a heating roller and a pressure roller) of the fixing unit 25. It is thermally fixed to the material 26. On the other hand, the belt 30 after the transfer of the transfer material is cleaned by the cleaning blade 29.
[0040]
Also in the case of the present embodiment, the speed of the belt 30 as a transfer member is increased from 1.0% to 4.0% and the speed of the registration unit 24 is increased by 2.5% with respect to the peripheral speed of the photoconductor 23. , And the speed of the fixing section 25 is increased from 2.5% to 3.5%. (Claim 20). In the above embodiment, the visible image (toner image) on the photoconductor 23 is not limited to a single color, but may be a color visible image (color toner image) having a plurality of colors. .
[0041]
[Example 3]
A third embodiment of the present invention will be described with reference to FIG. FIG. 15 is a view showing an example of a schematic configuration of an image forming apparatus. This image forming apparatus includes an image forming unit 52 having a configuration as shown in FIG. A visible image (toner image) is formed on the photoconductor 23 by the image forming unit 52. Then, a sheet is fed from one sheet feeding tray 53 of the multi-stage sheet feeding tray of the sheet feeding section, and is formed on the photosensitive member 23 on a transfer material such as a recording sheet conveyed through the registration section 24. A visible image (toner image) is transferred. At this time, in the present embodiment, as in the second embodiment, a visible image (toner image) is transferred onto the transfer material without image dropout and image expansion, and is fixed by the fixing unit 25, and is discharged by the discharge unit 54. Then, a transfer material on which an image is formed is discharged (claim 23).
Here, the image forming unit 52 has the same configuration as that of FIG. 14, but in addition, any of the image forming units according to claims 19 to 22, such as the image forming unit having the configuration shown in FIG. No problem.
[0042]
【The invention's effect】
As described above, according to the first aspect of the invention, a rotatable image carrier, image forming means for forming a toner image on the image carrier, and transfer of the toner image from the image carrier to a transfer material A transfer member that contacts a surface of the transfer material sent between the transfer member and the image carrier opposite to the surface on the image carrier side, and the transfer material transport direction A transport unit that is located at the preceding stage of the image carrier and transports the transfer material at the timing of the transfer of the toner image; and a fixing unit that is similarly located at the later stage of the image carrier and thermally fixes the toner image on the transfer material. Wherein the speed of the transfer member is 1.0% to 4.0% faster than the peripheral speed of the image carrier at the time of the transfer, and the speed of the transport unit and the fixing unit is the image speed. It is faster than the peripheral speed of the carrier In is an abnormal image due to the transfer, incomplete toner, and an image elongation can provide stably avoid possible transfer conditions.
[0043]
According to a second aspect of the present invention, in the image forming method according to the first aspect, the speed of the transport unit is 2.5% to 4.5% faster than the peripheral speed of the image carrier, and the speed of the fixing unit is higher than the peripheral speed. Since the peripheral speed is 2.5% to 3.5% faster than the peripheral speed of the image carrier, the range of the speed conditions in the conveying unit and the fixing unit is clearly specified, and the design becomes possible. According to a third aspect of the present invention, in the image forming method according to the first or second aspect, at least one of the rotation driving sources of the image carrier and the transfer member is a stepping motor. Therefore, the speed accuracy of the image carrier or the transfer member is improved, and the reliability of the operation and effect according to claim 1 or 2 is improved. According to a fourth aspect of the present invention, in the image forming method according to the third aspect, the rotation driving source of the image carrier is a stepping motor, and the transfer member is driven in synchronization with the driving of the image carrier. Therefore, in addition to the function and effect of claim 3, the speed accuracy of the image carrier and the transfer member is improved at a low cost using one stepping motor, the reliability is further improved, and the abnormal image accompanying the transfer is improved. Can be avoided.
According to a fifth aspect of the present invention, in the image forming method according to the third aspect, each of the rotation driving sources of the image carrier and the transfer member is an independent stepping motor. Since the rotational drive by the stepping motor can be independently applied to the body and the transfer member, the speed settings of the two do not depend on each other, so that the degree of freedom of the speed setting is increased, and the design margin is further improved.
According to a sixth aspect of the present invention, in the image forming method of the third, fourth or fifth aspect, the transporting unit, the fixing unit, or both of them are stepping motors. Therefore, since the stepping motor is used for the rotation drive source of the transport unit and / or the fixing unit, the speed accuracy of the transport unit and the fixing unit is improved, and the reliability of the operation and effect according to claim 2 is further improved.
[0044]
In the invention according to claim 7, in the image forming method according to any one of claims 1 to 6, the hardness of the transfer member is 20 ° to 45 ° in ASKER-C hardness, and the transfer member is pressed against the image carrier. Force 50g / cm ² ~ 400g / cm ² Therefore, the design conditions for a transfer member having a higher hardness than before are presented, and a transfer member having a higher hardness and higher durability can be used, and a longer life and a higher durability can be achieved. Can be achieved.
In the invention according to claim 8, in the image forming method according to any one of claims 1 to 7, the material of the transfer member is a foamable sponge rubber material of phenyl silicone rubber. Therefore, a long life and high durability can be achieved because the transfer member is made of a material having high antioxidant and anti-dielectric breakdown properties.
Further, according to the ninth aspect of the present invention, in the image forming method according to any one of the first to eighth aspects, the transfer member is formed of at least two or more layers, and the surface layer has a thickness smaller than that of another layer. The transfer member is made of a material having a high abrasion resistance (generally having a relatively high hardness). Since the layer is formed, abrasion resistance is improved.
According to a tenth aspect of the present invention, in the image forming method according to any one of the first to ninth aspects, the core portion of the transfer member has a structure of at least two layers and is detachably mounted in the axial direction. In addition, since the transfer material is fixed in the transport direction, the core portion can be used as a shared component, that is, a reused product, with respect to the transfer member.
According to an eleventh aspect of the present invention, in the image forming method according to the tenth aspect, the transfer member is replaced every service life or a prescribed period. And improve customer satisfaction.
[0045]
In the image forming method according to the twelfth aspect, in the image forming method according to any one of the first to eleventh aspects, an extending direction A from the holding direction of the transfer material to the image carrier side in the transporting unit; The angle AB between the body and the transfer member in the direction of extension B from the transfer material holding direction to the transport unit side in the following range,
40 ° ≤ angle AB ≤ 60 °
In addition, since at least a transfer material transport guide is provided in the vicinity of the intersection of the direction A and the direction B, the design conditions between the transport unit, the image bearing member, and the transfer member satisfy the requirements of claims 1 and 2. , The actual design becomes easier.
According to a thirteenth aspect of the present invention, in the image forming method according to any one of the first to twelfth aspects, an extension direction C from the holding direction of the transfer material in the fixing unit to the image carrier side, The angle CD between the image carrier and the transfer member and the direction of extension D from the transfer material holding direction to the fixing unit side is in the following range,
30 ° ≦ angle CD ≦ 40 °
In addition, since at least a transfer material transport guide is provided in the vicinity of the intersection of the direction C and the direction D, the design conditions between the image bearing member and the transfer member to the fixing unit satisfying claims 1 and 2 are satisfied. , The actual design becomes easier.
Further, in the invention according to Claim 14, in the image forming method according to any one of Claims 1 to 13, at least the image carrier and the transfer member are located at a position closer to the transport unit than a transfer material holding position between the image carrier and the transfer member. One transfer material deflection amount detecting means, and control means for changing the speed of the transport unit in accordance with the transfer material deflection amount L from the transfer material deflection amount detection means. According to the speed fluctuation occurring during the conveyance, a means for removing the speed fluctuation is prepared, and the reliability of avoiding the abnormal image accompanying the transfer is further improved.
According to a fifteenth aspect of the present invention, in the image forming method according to the fifteenth aspect, the transfer material deflection amount L is closer to the transport unit than a transfer material holding position between the image carrier and the transfer member. The transfer material, or a part of the transfer material, is set to zero when the transfer material or the transfer member has an extension on the transfer member side from the transfer material holding direction in the image carrier and the transfer member, and the transfer in the transfer portion is performed. When the distance from the material holding position to the line segment E connecting the transfer material holding position between the image carrier and the transfer member is a positive value when approaching and a negative value when the distance is away, the transfer material deflection amount L is A control means for increasing the speed of the transport unit in the case of a positive value and decreasing the speed in the case of a negative value is provided. And easily embodied Kill.
[0046]
According to a sixteenth aspect of the present invention, in the image forming method according to any one of the first to fifteenth aspects, at least one transfer material deflection amount is detected near the image carrier side from a transfer material holding position in the transport unit. Means, and control means for changing the speed of the transport section in accordance with the transfer material deflection amount L 'from the transfer material deflection amount detection means. In addition, the means for detecting and removing the speed fluctuation occurring during the transfer material conveyance more quickly is prepared, and the reliability of avoiding the abnormal image accompanying the transfer is further improved.
Further, in the image forming method according to the seventeenth aspect, in the image forming method according to the sixteenth aspect, the transfer material flexure amount L ′ is closer to the image carrier side than the transfer material holding position in the transport unit. Or, when a part of the transfer material has an extension on the image carrier side from the transfer material holding direction in the transport unit, the value is zero, and a positive value when approaching the line segment E from zero, and When the separation time is set to a negative value, when the transfer material deflection amount L ′ is positive, the transfer unit increases the speed, and when the transfer material deflection amount L ′ is negative, the control unit decreases the speed. In the operation and effect of the sixteenth aspect, the speed fluctuation removing means is specifically shown, and can be easily realized.
Further, in the image forming method according to the eighteenth aspect, in the image forming method according to any one of the fourteenth to seventeenth aspects, according to the transfer material deflection amount L and the transfer material deflection amount L ′, Since the control means for changing the speed is provided, it has the function and effect of any one of claims 14 to 17, and can achieve high reliability of avoiding abnormal images accompanying transfer.
[0047]
The invention according to claim 19 is a rotatable image carrier, image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material. A transfer member that is in contact with a surface of the transfer material sent between the transfer member and the image carrier opposite to the surface on the image carrier side, and is provided at a front stage of the image carrier in the transfer material transport direction. An image forming unit having a transport unit that transports the transfer material at a timing that is located at the timing of transferring the toner image, and a fixing unit that is similarly located at the subsequent stage of the image carrier and thermally fixes the toner image on the transfer material. The image forming method according to any one of claims 1 to 18, wherein the transfer member is a roller, so that a roller transfer type image forming unit can be easily designed. Become.
[0048]
According to a twentieth aspect of the present invention, there is provided a rotatable image carrier, image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material. A transfer member that is in contact with a surface of the transfer material sent between the transfer member and the image carrier opposite to the surface on the image carrier side, and at a stage preceding the image carrier in the transfer material transport direction. An image forming unit having a transport unit that transports the transfer material at a timing that is located at the timing of transferring the toner image, and a fixing unit that is similarly located at the subsequent stage of the image carrier and thermally fixes the toner image on the transfer material. The image forming method according to any one of claims 1 to 18, wherein the transfer member includes a belt that contacts the image carrier, and a roller that contacts the belt opposite to the image carrier side of the belt. Since it is characterized by having Design of the image forming units of belt transfer method is readily possible.
[0049]
In the invention according to claim 21, in the image forming unit according to claim 19 or 20, the image carrier and the transfer member are vertically above the transport unit, and the fixing unit is the image carrier. And the transfer member is vertically above the transfer member, so that the stability of transfer material transfer is relatively low. Even if the transfer section to the fixing section is a vertical transfer image forming unit, an abnormal image due to transfer Stable avoidance can be achieved.
According to a twenty-second aspect of the present invention, since a plurality of the image forming units according to any one of the nineteenth to twenty-first aspects are provided, a design of a color image forming unit capable of avoiding an abnormal image due to transfer is provided. Becomes possible.
According to a twenty-third aspect of the present invention, there is provided an image forming apparatus for forming a toner image on an image carrier, transferring the toner image to a transfer material, fixing the toner image, and outputting the image. Since the image forming unit includes the image forming unit described above, it is possible to design an image forming apparatus including the image forming unit according to any one of claims 19 to 22.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a schematic main configuration of an image forming apparatus (image forming unit) to which an image forming method according to the present invention is applied.
FIG. 2 is a diagram showing a slip ratio (experimental value) between a photosensitive member and a transfer material in one embodiment of the present invention.
FIG. 3 is a diagram showing a slip ratio (simulation result) between a photosensitive member and a transfer material in one embodiment of the present invention.
FIG. 4 is a diagram showing a slip ratio (a simulation result when the speed of a resist portion is changed) between a photosensitive member and a transfer material in one embodiment of the present invention.
FIG. 5 is a diagram illustrating a slip ratio (a simulation result when the speed of a resist unit is changed) between a photosensitive member and a transfer material according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a configuration example in which at least one of the rotation driving sources of the photoconductor and the transfer roller is a stepping motor according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating a configuration example of a photoconductor and a transfer roller being rotationally driven by a stepping motor (when the photoconductor and the transfer roller are gear-driven) according to an embodiment of the present invention.
FIG. 8 is a diagram illustrating an example of a configuration in which a photoconductor and a transfer roller are rotationally driven by a stepping motor (when both the photoconductor and the transfer roller are driven by independent stepping motors) according to an embodiment of the present invention.
FIG. 9 is a diagram illustrating a configuration example of a transfer roller according to an embodiment of the present invention.
FIG. 10 is a diagram illustrating a layout of a registration unit, a photoconductor, and a transfer roller according to an embodiment of the present invention.
FIG. 11 is a diagram illustrating a layout of a photoconductor, a transfer roller, and a fixing unit according to an embodiment of the present invention.
FIG. 12 is a diagram illustrating an example of a paper deflection amount detection unit and a control unit provided near a photoconductor and a transfer roller according to an embodiment of the present invention.
FIG. 13 is a diagram illustrating an example of a paper deflection amount detection unit and a control unit installed near a registration unit according to an embodiment of the present invention.
FIG. 14 is a view showing another embodiment of the present invention, and is a schematic view of a main configuration of an image forming unit using a belt as a transfer member.
FIG. 15 is a schematic configuration diagram illustrating an example of an image forming apparatus in which the present invention is implemented.
FIG. 16 is a diagram illustrating an example of a shape of a transfer process of a transfer material conveyed from a resist unit to a fixing unit via a transfer unit.
FIG. 17 is a diagram illustrating a schematic configuration example of a transfer device and devices before and after the transfer device in a conventional image forming apparatus.
[Explanation of symbols]
1: Image carrier
2: Transfer member
3: Contact part
4: Transfer material
5: Transport unit
6: Fixing section
7: Transfer device
8: Photoreceptor (image carrier)
9: transfer roller (transfer member)
10: Contact part
11: transfer material
12: Resist part
13: Fixing section
15: Charging roller
16: Developing device
17: Laser light
18: Cleaner
19a: transport path
19b: transport path
20: Power supply
21: Low slip ratio range
22a, 22b, 22c: Stepping motor
23: Photoconductor (image carrier)
24: resist section
25: Fixing unit
26: transfer material
27: Contact part
28: Power supply
29: Cleaning blade
30: belt for transfer and transfer (transfer member)
31: drive roller
32: Support roller
33: Electrode roller
36b, 36c: Motor
37a, 37b: gear
38: Stepping motor
39a, 39b: Stepping motor
40: transfer member of foamable sponge rubber material of phenyl silicone rubber
41, 41a, 41b: core metal
42a: Surface layer
42b: Middle layer
43: Transfer roller surface
49a, 49b: transport guide
50a, 50b: control means
51a, 51b: paper deflection amount detecting means
52: Image forming unit
53: Paper tray
54: Discharge unit

Claims (23)

A rotatable image carrier, an image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material, wherein the transfer member and the image carrier And a transfer member that is in contact with a surface of the transfer material that is sent between the image carrier side and a surface opposite to the image carrier side. In the image forming method having a transport unit that transports the transfer material at the timing of, and a fixing unit that is similarly located at a later stage of the image carrier and thermally fixes the toner image on the transfer material.
During the transfer, the speed of the transfer member is 1.0% to 4.0% faster than the peripheral speed of the image carrier, and the speeds of the transport unit and the fixing unit are higher than the peripheral speed of the image carrier. An image forming method characterized by being fast. The image forming method according to claim 1,
The speed of the transport unit is 2.5% to 4.5% faster than the peripheral speed of the image carrier, and the speed of the fixing unit is 2.5% to 3.5% faster than the peripheral speed of the image carrier. An image forming method, comprising: The image forming method according to claim 1, wherein
An image forming method, wherein at least one of the rotation driving sources of the image carrier and the transfer member is a stepping motor. The image forming method according to claim 3,
An image forming method, wherein the rotation driving source of the image carrier is a stepping motor, and the transfer member is driven in synchronization with the driving of the image carrier. The image forming method according to claim 3,
The image forming method according to claim 1, wherein each rotation drive source of the image carrier and the transfer member is an independent stepping motor. The image forming method according to claim 3, 4 or 5,
An image forming method, wherein the transport unit, the fixing unit, or both of them are stepping motors. The image forming method according to any one of claims 1 to 6,
Image forming wherein the hardness of the transfer member 20 ° to 45 ° in ASKER-C hardness, pressing force to the image bearing member is ^{50g / cm 2 ~400g / cm 2} . 8. The image forming method according to claim 1, wherein the material of the transfer member is a foamable sponge rubber material of phenyl silicone rubber. The image forming method according to any one of claims 1 to 8,
The transfer member is made of at least two or more layers of material, and the surface layer is thinner than the thickness of the other layer, and higher than the hardness of the other layer, and has a friction coefficient of 1.0 or more. Image forming method. The image forming method according to any one of claims 1 to 9,
An image forming method, wherein the core portion of the transfer member has a structure of at least two layers, is attached and detached in the axial direction, and is fixed in the transport direction of the transfer material. The image forming method according to claim 10,
An image forming method, wherein the transfer member is replaced at every service life or a specified period. The image forming method according to any one of claims 1 to 11,
An angle AB between an extension direction A from the transfer material holding direction in the transfer unit to the image carrier side and an extension direction B from the transfer material holding direction in the image carrier and the transfer member to the transfer unit side. Is in the following range,
40 ° ≤ angle AB ≤ 60 °
And an image forming method, wherein at least a transfer material transport guide is provided in the vicinity of the intersection of the direction A and the direction B. The image forming method according to any one of claims 1 to 12,
An angle CD between an extension direction C of the fixing portion from the transfer material holding direction to the image carrier side and an extension direction D of the image carrier and the transfer member from the transfer material holding direction to the fixing portion side. Is in the following range,
30 ° ≦ angle CD ≦ 40 °
An image forming method comprising providing at least a transfer material transport guide near an intersection of the direction C and the direction D. The image forming method according to any one of claims 1 to 13,
At least one transfer material deflection amount detection means is provided near the transfer section between the transfer material holding position of the image carrier and the transfer member, and the transfer material deflection amount L from the transfer material deflection amount detection means is provided. An image forming method, comprising: a control unit that changes the speed of the transport unit according to the condition. The image forming method according to claim 14,
The transfer material deflection amount L may be set such that the transfer material or a part of the transfer material closer to the transport unit side than the transfer material holding position in the image carrier and the transfer member is the image carrier and the transfer material. When the transfer member is located on an extension from the transfer material holding direction to the transfer section side with respect to the transfer material, the transfer material is held between the image carrier and the transfer member from the transfer material hold position in the transfer section. When the distance to the line segment E connecting the positions is a positive value, and when the distance is a negative value, it is a negative value. When the deflection amount L of the transfer material is positive, the speed of the transport unit is increased. An image forming method, comprising: a control unit that reduces the number of images. The image forming method according to any one of claims 1 to 15,
The transfer unit has at least one transfer material deflection amount detecting means near the transfer material holding position from the transfer material holding position, and transfers the transfer material according to the transfer material deflection amount L ′ from the transfer material deflection amount detection unit. An image forming method, comprising: a control unit that changes a speed of a set. The image forming method according to claim 16,
The transfer material deflection amount L ′ may be set such that the transfer material or a part of the transfer material closer to the image carrier than the transfer material gripping position in the transport unit is in the transfer material gripping direction in the transport unit. When the transfer material deflection amount L 'is positive, when it is on the extension to the image carrier side, it is zero, when it approaches the line segment E from zero, and when it is away from it is a negative value, it is positive. The image forming method according to claim 1, further comprising control means for increasing the speed of the transport unit and decreasing the speed when the speed is negative. The image forming method according to any one of claims 14 to 17,
An image forming method comprising: a control unit that changes a speed of the transport unit according to the transfer material deflection amount L and the transfer material deflection amount L ′. A rotatable image carrier, an image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material, wherein the transfer member and the image carrier And a transfer member that is in contact with a surface of the transfer material that is sent between the image carrier side and a surface opposite to the image carrier side. In the image forming unit having a fixing unit for thermally fixing the toner image on the transfer material, which is similarly located at the subsequent stage of the image carrier, and
An image forming unit using the image forming method according to claim 1, wherein the transfer member is a roller. A rotatable image carrier, an image forming means for forming a toner image on the image carrier, and a transfer member for transferring a toner image from the image carrier to a transfer material, wherein the transfer member and the image carrier And a transfer member that is in contact with a surface of the transfer material that is sent between the image carrier side and a surface opposite to the image carrier side. In the image forming unit having a fixing unit for thermally fixing the toner image on the transfer material, which is similarly located at the subsequent stage of the image carrier, and
The image forming method according to claim 1, wherein the transfer member includes a belt that contacts the image carrier, and a roller that contacts the belt opposite to the image carrier side of the belt. An image forming unit comprising: The image forming unit according to claim 19, wherein
The image forming unit, wherein the image carrier and the transfer member are vertically above the transport unit, and the fixing unit is vertically above the image carrier and the transfer member. An image forming unit comprising a plurality of the image forming units according to any one of claims 19 to 21. An image forming apparatus for forming a toner image on an image carrier, transferring the toner image to a transfer material, fixing and outputting the same,
An image forming apparatus comprising the image forming unit according to any one of claims 19 to 22.

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