JP3627122B2

JP3627122B2 - Charging device and image forming apparatus using the charging device

Info

Publication number: JP3627122B2
Application number: JP06917797A
Authority: JP
Inventors: 貞夫高橋; 岳郎榑沼; 武男須田; 勝田中
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1997-03-06
Filing date: 1997-03-06
Publication date: 2005-03-09
Anticipated expiration: 2017-03-06
Also published as: JPH10254220A

Description

【０００１】
【発明の属する技術分野】
本発明は、帯電装置及びその帯電装置を使用する画像形成装置に関するものである。更に詳しくは、帯電部材により被帯電体に振動電圧を印加して被帯電体を帯電する帯電装置及びその帯電装置を使用する電子写真方式を用いた複写機、プリンタ、ファクシミリ装置あるいはそれらの複合機に関するものである。
【０００２】
【従来の技術】
従来の帯電装置及びその帯電装置を使用する画像形成装置として、帯電部材を被帯電体に接触又は離間させた状態で振動電圧を被帯電体に印加するに際し、振動電界の周波数の範囲や空間周波数、或は被帯電体の移動速度や基材の振動の対数減衰率等を特定することによって、被帯電体の帯電を均一に行うと共にオゾンや振動音の発生を低減するようにした技術は公知である（特開平３−１００６７４号、特開平３−１００６７５号、特開平３−１０１７６４号、特開平４−６７０７２号等の公報を参照）。
振動電圧を被帯電体に印加するに際し、被帯電体が振動して帯電音による異音を生成することを防止するために、被帯電体の質量を大きくしたり、或は重量物により負荷を与えて被帯電体の振動による変形を少なくするようにした技術も公知である（特開平５−３５０４８号、特開平５−３５０５１号、特開平８−１７９６５６号等の公報を参照）。
然し、これらの従来技術にあっては、被帯電体の振動により発生する帯電音による異音の発生を防止するために、重量の増加ばかりでなく、コスト高という問題も生じていた。
又、被帯電体が振動した時の帯電音による異音の発生を防止するために、被帯電体の剛性をヤング率（縦弾性係数）や肉厚の調整により高くすることにより、被帯電体の振動による変形を少なくするようにした技術も公知であるが、前述と同様にコスト高であった（特開平５−３５０５０号公報を参照）。
従って、従来の帯電装置及びその帯電装置を使用する画像形成装置は、帯電部材からの振動電圧の印加によって被帯電体を帯電する際に、被帯電体が振動したときの帯電音による異音の発生を防止するために、制振用の錘を用いるとその分だけ重量が増加するだけでなく、コスト高にもなると言う不具合が生じていた。
【０００３】
【発明が解決しようとする課題】
前述した従来の帯電装置及びその帯電装置を使用する画像形成装置は、帯電部材が振動電圧を印加して被帯電体を帯電する際に、被帯電体の振動による帯電音による異音の発生を防止するために制振用の錘を用いると、重量が増加するだけでなく、コスト高にもなると言う問題があった。
そこで本発明の課題は、このような問題点を解決するものである。即ち、帯電部材が振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置及びその帯電装置を使用する画像形成装置を提供することを目的にしている。
【０００４】
【課題を解決するための手段】
上記目的を達成するために、請求項１の発明は、帯電部材により被帯電体に振動電圧を印加して被帯電体を帯電させる帯電装置において、周波数（ｆ₀）の振動電圧を有する帯電部材と、固有振動数（ｆ₁）を有する被帯電体と、該被帯電体を構成するシリンダの両端開口部に夫々嵌合され、その開口内部を支持する支持部材の支持点間の距離によって決定される被帯電体の長さ（ｌ）を変更することにより上記固有振動数（ｆ₁）を調整する調整手段とを有し、ｆ₁≦２ｆ₀である場合の上記被帯電体の固有振動数（ｆ₁）を上記帯電部材の振動電圧の周波数（ｆ₀）と（２ｆ₀）の中間の値の周波数とし、ｆ₁≧２ｆ₀である場合の上記被帯電体の固有振動数（ｆ₁）を（２ｆ₀）と（３ｆ₀）の中間の値の周波数にすることにより異音の発生を防止することを特徴とする。
請求項２の発明は、請求項１記載の帯電装置において、上記調整手段により、帯電部材により周波数（ｆ₀）の振動電圧が印加される固有振動数（ｆ₁）を有する被帯電体を支持する支持部材の支持位置を移動させることにより、上記被帯電体の長さ（ｌ）を変更して、ｆ₁≦２ｆ₀である場合の上記被帯電体の固有振動数（ｆ₁）をｆ₁＝（ｆ₀＋２ｆ₀）／２とし、ｆ₁≧２ｆ₀である場合の上記被帯電体の固有振動数（ｆ₁）がｆ₁＝（２ｆ₀＋３ｆ₀）／２となるように上記被帯電体の固有振動数（ｆ₁）を調整して異音の発生を防止するようにしたことを特徴とする。
請求項３の発明は、請求項１又は２記載の帯電装置において、上記帯電部材と上記被帯電体とを接触させた状態で上記振動電圧を印加させるようにしたことを特徴とする。
請求項４の発明は、請求項１又は２記載の帯電装置において、上記帯電部材と上記被帯電体とを非接触状態にした状態で上記振動電圧を印加させるようにしたことを特徴とする。
請求項５の発明は、請求項１、２、３又は４記載の帯電装置において、上記帯電部材を帯電ローラとしたことを特徴とする。
請求項６の発明は、請求項１、２、３、４又は５記載の帯電装置において、被帯電体を像担持体としたことを特徴とする。
請求項７の発明は、上記帯電装置と、上記帯電装置の帯電部材により均一に帯電された被帯電体上を露光して静電潜像を形成する露光手段と、上記露光手段により形成された静電潜像を現像してトナー画像を形成する現像手段とを有し、上記帯電装置が、請求項１、２、３、４、５又は６記載の帯電装置とを備えていることを特徴とする。
【０００５】
【作用】
上記のように構成された帯電装置及びその帯電装置を使用する画像形成装置は、請求項１においては、周波数（ｆ₀）の振動電圧を有する帯電部材によって、固有振動数（ｆ₁）を有する被帯電体を、調整手段による調整により、上記被帯電体の長さ（ｌ）の変更で固有振動数（ｆ ₁ ）を調整出来るようにして、ｆ ₁ ≦２ｆ ₀ の場合の上記被帯電体の固有振動数（ｆ ₁ ）は、上記帯電部材の振動電圧の周波数（ｆ ₀ ）と（２ｆ ₀ ）の中間の周波数になるように、ｆ ₁ ≧２ｆ ₀ の場合の上記被帯電体の固有振動数（ｆ ₁ ）は、（２ｆ ₀ ）と（３ｆ ₀ ）の中間の周波数で帯電するようにしたので、簡単な調整作業により、上記帯電部材が振動電圧を印加して上記被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
【０００６】
請求項２においては、周波数（ｆ₀）の振動電圧を有する帯電部材によって、固有振動数（ｆ₁）を有する被帯電体を、調整手段で上記被帯電体の長さ（ｌ）の変更で固有振動数（ｆ₁）を調整出来るようにして、ｆ₁≦２ｆ₀の場合に、上記被帯電体の固有振動数（ｆ₁）を、ｆ₁＝（ｆ₀＋２ｆ₀）／２に、ｆ₁≧２ｆ₀の場合に、上記被帯電体の固有振動数（ｆ₁）を、ｆ₁＝（２ｆ₀＋３ｆ₀）／２で帯電するようにしたので、簡単な調整で上記帯電部材が振動電圧を印加して上記被帯電体を帯電する際の、異音の発生を容易に確実に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
請求項３においては、周波数（ｆ₀）の振動電圧を有する帯電部材によって、上記帯電部材と接触する固有振動数（ｆ₁）を有する被帯電体を、ｆ₁≦２ｆ₀の場合の上記被帯電体の固有振動数（ｆ₁）は、上記帯電部材の振動電圧の周波数（ｆ₀）と（２ｆ₀）の中間の周波数になるように、ｆ₁≧２ｆ₀の場合の上記被帯電体の固有振動数（ｆ₁）は、（２ｆ₀）と（３ｆ₀）の中間の周波数で帯電するようにしたので、上記帯電部材が低い振動電圧を印加して上記被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
【０００７】
請求項４の発明においては、周波数（ｆ₀）の振動電圧を有する帯電部材によって、上記帯電部材と離間する固有振動数（ｆ₁）を有する被帯電体を、ｆ₁≦２ｆ₀の場合の上記被帯電体の固有振動数（ｆ₁）は、上記帯電部材の振動電圧の周波数（ｆ₀）と（２ｆ₀）の中間の周波数になるように、ｆ₁≧２ｆ₀の場合の上記被帯電体の固有振動数（ｆ₁）は、（２ｆ₀）と（３ｆ₀）の中間の周波数で帯電するようにしたので、上記帯電部材が上記被帯電体表面を損傷することなく振動電圧を印加して上記被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
請求項５においては、周波数（ｆ₀）の振動電圧を有する帯電ローラによって、固有振動数（ｆ₁）を有する被帯電体を、ｆ₁≦２ｆ₀の場合の上記被帯電体の固有振動数（ｆ₁）は、上記帯電ローラの振動電圧の周波数（ｆ₀）と（２ｆ₀）の中間の周波数になるように、ｆ₁≧２ｆ₀の場合の上記被帯電体の固有振動数（ｆ₁）は、（２ｆ₀）と（３ｆ₀）の中間の周波数で帯電するようにしたので、上記帯電ローラが振動電圧を印加して上記被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
【０００８】
請求項６においては、周波数（ｆ₀）の振動電圧を有する帯電部材によって、固有振動数（ｆ₁）を有する像担持体を、ｆ₁≦２ｆ₀の場合の上記像担持体の固有振動数（ｆ₁）は、上記帯電部材の振動電圧の周波数（ｆ₀）と（２ｆ₀）の中間の周波数になるように、ｆ₁≧２ｆ₀の場合の上記像担持体の固有振動数（ｆ₁）は、（２ｆ₀）と（３ｆ₀）の中間の周波数で帯電するようにして、上記帯電部材が振動電圧を印加して上記像担持体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
請求項７においては、周波数（ｆ₀）の振動電圧を有する帯電ローラによって、固有振動数（ｆ₁）を有する像担持体を、ｆ₁≦２ｆ₀の場合の上記像担持体の固有振動数（ｆ₁）は、上記帯電ローラの振動電圧の周波数（ｆ₀）と（２ｆ₀）の中間の周波数になるように、ｆ₁≧２ｆ₀の場合の上記像担持体の固有振動数（ｆ₁）は、（２ｆ₀）と（３ｆ₀）の中間の周波数で帯電するようにしたので、上記帯電ローラが振動電圧を印加して上記像担持体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を使用して画像を形成する画像形成装置を提供することが出来る。
【０００９】
【発明の実施の形態】
次に、本発明の実施の形態について図面を参照して説明する。
図１は本発明の一形態例の帯電装置の構成例を示す断面図であり、この帯電装置は、例えば電子写真方式を用いた複写機、プリンタ、ファクシミリ装置あるいはそれらの複合機等の画像形成装置に使用され、周波数（ｆ_０）の振動電圧を有する帯電部材１である帯電ローラ１ａを、固有振動数（ｆ_１）を有する被帯電体２である像担持体２ａに接触させた状態で、周波数（ｆ_０）の振動電圧を印加して像担持体２ａを帯電させる。
尚、図示していないが、周波数（ｆ_０）の振動電圧を有する帯電ローラ１ａを、固有振動数（ｆ_１）を有する像担持体２ａから離間させた非接触状態で、周波数（ｆ_０）の振動電圧を印加して像担持体２ａを帯電するように構成してもよく、この場合には像担持体２ａ表面は接触により発生する損傷を回避出来る。
帯電ローラ１ａが像担持体２ａを帯電する印加電圧は、例えば直流電圧を−８００Ｖ、交流電圧のピーク間電圧を２０００Ｖ、周波数（ｆ_０）を５５０Ｈｚとする。
像担持体２ａは、中空円筒状のシリンダ２ｂの表面に、厚さ２０μｍの０ＰＣの感光層２ｃを塗布したものであり、シリンダ２ｂの両端開口部内に夫々支持部材４を嵌合することにより支持している。支持部材４は、外周面に駆動力伝達歯車８を有する一方側軸受４ａと、他方側軸受４ｂとから成り、一方側軸受４ａの内側端部に位置する支持部４ａ_１と、他方側軸受４ｂの内側端部に位置する支持部４ｂ_１の外周面によってシリンダ２ｂの内周面を支持している。
【００１０】
支持部材４を構成する一方側軸受４ａと他方側軸受４ｂは、例えばポリカーボネイト等の樹脂により構成することにより、一層軽量で生産性に優れた低コストの帯電装置を提供出来る。一方側軸受４ａの支持部４ａ₁及び他方側軸受４ｂの支持部４ｂ₁は、シリンダ２ｂの軸方向両端側開口内に夫々軽圧入等により軸方向へ移動可能な状態で仮に固定される。調整手段３は、各軸受４ａ，４ｂを同期して軸方向内外へ等距離移動させる為の手段である。或は、各軸受４ａ，４ｂはシリンダ２ｂ内の適所に接着等によって固定してもよい。シリンダ２ｂは、例えばアルミニウム材等の金属材料で構成し、例えばその外径は３０ｍｍ、厚さは０．７５ｍｍ、長さは２６０ｍｍで上記駆動力伝達用歯車８を介して伝達される図示しないモータからの駆動力により、周速９０ｍｍ／ｓｅｃで回転駆動される。
被帯電体２である像担持体２ａの固有振動数（ｆ₁）は、シリンダ２ｂの形状、重量等により決まり、次式で求められる。
（ｆ₁）＝λ²／２πｌ²・（ＥＩ／Ａρ）^1/2
なお、λは振動数係数、Ｅはアルミニウムのヤング率で６．８６×１０¹⁰Ｎ／ｍ²、Ｉは断面２次モーメント、Ａは断面積、ρはアルミニウムの比重で２８００Ｋｇ／ｍ³、λは両端支持で一次振動とするとλ＝πである。
【００１１】
すなわち、像担持体２ａの固有振動数（ｆ_１）は、１１９０Ｈｚであり、帯電ローラ１ａの印加電圧の周波数（ｆ_０）は５５０Ｈｚであるため、ｆ_１（１１９０Ｈｚ）はｆ_０の２倍の値である１１００Ｈｚに近くなる。つまり、帯電部材１の印加電圧の周波数（ｆ_０）及びその整数倍の周波数ｎ（ｆ_０）に対して、像担持体２ａの固有振動数（ｆ_１）が共振して共鳴による帯電音が異常音となって発生する。
【００１２】
これに対して本形態例では、ｆ₁≧２ｆ₀の関係にある場合には、シリンダ２ｂの一端開口内部を支持する一方側軸受４ａ（支持部４ａ₁）及び他方側軸受４ｂ（支持部４ｂ₁）を夫々シリンダ２ｂの両端側からそれぞれ図示の矢印Ａ又は矢印Ｂ方向の内部方向に等距離づつ移動させて、支持部４ａ₁と支持部４ｂ₁との間の支持点間距離、つまり支持部４ａ ₁ の左端面と支持部４ｂ ₁ の右端面との間の距離によって決定される像担持体２ａの長さ（ｌ）を２４０ｍｍに変更することにより、像担持体２ａの固有振動数（ｆ₁）を１４００Ｈｚに変更することができ、帯電ローラ１ａの印加電圧の２倍周波数と３倍周波数より最も離れた中間値の周波数に近づけることができる。即ち、固有振動数（ｆ₁）を、（２倍周波数１１００Ｈｚ＋３倍周波数１６５０Ｈｚ）／２＝１３７５Ｈｚに隣接して、共振、共鳴による異常音の発生しない中間の周波数にすることにより、異音の発生を防止する帯電装置を提供することが出来るようになった。
つまり、この形態例は、ｆ₁≧２ｆ₀の場合に、像担持体２ａの固有振動数（ｆ₁）を、ｆ₁＝（２ｆ₀＋３ｆ₀）／２となるように構成した点が特徴的である。
【００１３】
次に、シリンダ２ｂを長さ３４０ｍｍにすると、像担持体２ａの固有振動数（ｆ₁）は、シリンダ２ｂの構造により決まり、次式で求められる。
（ｆ₁）＝λ２／２πｌ ²・（ＥＩ／Ａρ） ^1/2
ここで、λは振動数係数、Ｅはアルミニウムのヤング率で６．８６×１０¹⁰Ｎ／ｍ²、Ｉは断面２次モーメント、Ａは断面積、ρはアルミニウムの比重で２８００Ｋｇ／ｍ³、λは両端支持で一次振動とするとλ＝πである。
この式によれば、像担持体２ａの固有振動数（ｆ₁）は７００Ｈｚであり、この値は帯電ローラ１ａの印加電圧の周波数（ｆ₀）の５５０Ｈｚに近い為に、帯電ローラ１ａの印加電圧の周波数（ｆ₀）及びその整数倍の周波数ｎ（ｆ₀）に像担持体２ａの固有振動数（ｆ₁）が近いことにより共振して共鳴による帯電音が異常音となって発生する。
【００１４】
これに対して、本発明の他の形態例では、ｆ₁≦２ｆ₀の場合には、シリンダ２ｂを支持する一方側軸受４ａ（支持部４ａ₁）及び他方側軸受４ｂ（支持部４ｂ₁）をシリンダ２ｂの両端側からそれぞれ等距離ずつ図示の矢印Ａ又は矢印Ｂ方向の内部方向に移動して、支持部４ａ₁と支持部４ｂ₁との支持点間距離、つまり像担持体２ａの長さ（ｌ）を３１０ｍｍとする。すると、像担持体２ａの固有振動数（ｆ₁）は、８３６Ｈｚとなり、帯電部材１の印加電圧の１倍周波数と２倍周波数より最も離れた中間値の周波数となる。つまり、像担持体２ａの固有振動数（ｆ₁）を（１倍周波数５５０Ｈｚ＋２倍周波数１１００Ｈｚ）／２＝８２５Ｈｚに隣接して、共振、共鳴による異常音の発生しない中間の周波数にすることにより、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。即ち、この形態例は、ｆ₁≦２ｆ₀の場合に、像担持体２ａの固有振動数（ｆ₁）が、ｆ₁＝（ｆ₀＋２ｆ₀）／２となるようにした点が特徴的である。
【００１５】
尚、上記形態例ではシリンダ２ｂが、アルミニウム材でその外径が３０ｍｍの場合について説明したが、外径が６０ｍｍ、その他の場合と同様に、像担持体２ａの固有振動数（ｆ_１）は、帯電ローラ１ａの印加電圧の各整数倍周波数と最も離れた周波数に隣接して、共振、共鳴による異常音の発生しない中間の周波数にすることにより、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来る。
調整手段３は、各軸受４ａ，４ｂの軸心孔に形成した雌螺子部４ａ_２，４ｂ_２に螺合した状態で貫通配置された送り螺子３ａと、送り螺子３ａの一端部に設けた調整部材３ｂ（操作ノブ）とから成り、送り螺子３ａの両端側に設けた捻れ方向が逆方向の螺子部３ａ１と螺子部３ａ２を、夫々一方側軸受４ａの雌螺子部４ａ_２と他方側軸受４ｂの雌螺子部４ｂ_２に螺合させ、手動又は自動的に上記送り螺子３ａと一体の調整部材３ｂを回動することによって、像担持体２ａの長さ（ｌ）を変更出来るようになっている。
【００１６】
本形態例では、調整手段３の調整部材３ｂを正逆いずれかの方向に所定角度（回数）回動することによって、帯電ローラ１ａにより周波数（ｆ_０）の振動電圧が印加される固有振動数（ｆ_１）を有する像担持体２ａを支持する支持部材４の支持部４ａ_１と支持部４ｂ_１の支持位置を移動することができ、この支持位置の移動によって像担持体２ａの長さ（ｌ）を変更して、ｆ_１ ≦２ｆ_０の場合に、像担持体２ａの固有振動数（ｆ_１）を、ｆ_１＝（ｆ_０＋２ｆ_０）／２に、ｆ_１ ≧２ｆ_０の場合に、像担持体２ａの固有振動数（ｆ_１）を、ｆ_１＝（２ｆ_０＋３ｆ_０）／２となるように像担持体２ａの固有振動数（ｆ_１）を調整して、共振して共鳴による異常音の発生しない中間の周波数にすることにより、異音の発生を防止することが出来るようになっている。
【００１７】
図２は本発明の帯電装置を電子写真方式を用いた複写機、プリンタ、ファクシミリ装置あるいはそれらの複合機等に適用した場合の概略構成図であって、高圧電源９により周波数（ｆ_０）の振動電圧を有する帯電ローラ１ａにより、固有振動数（ｆ_１）を有する像担持体２ａに、周波数（ｆ_０）の振動電圧を印加して、像担持体２ａ上を、上述のように帯電するようになっている。
帯電ローラ１ａにより均一に帯電された像担持体２ａ上は、露光手段６により露光されて静電潜像が形成された後、現像手段７により上記露光手段６により形成された静電潜像を現像したトナー画像を、転写手段１０により転写紙（Ｐ）に転写され、その転写紙（Ｐ）は定着手段１１でトナー像が定着後に装置外に排紙されて収納されるようになっている。
従って、帯電ローラ１ａが振動電圧を印加して像担持体１ａを帯電する際の、異音の発生を容易に防止すると共に軽量で低コストで、帯電して画像を形成する画像形成装置を提供することが出来るようになった。
【００１８】
【発明の効果】
以上のように請求項１の発明によれば、周波数（ｆ_０）の振動電圧を有する帯電部材によって、固有振動数（ｆ_１）を有する被帯電体を、ｆ_１ ≦２ｆ_０の場合には、被帯電体の固有振動数（ｆ_１）が、帯電部材の振動電圧の周波数（ｆ_０）と（２ｆ_０）の中間の周波数になるように、ｆ_１ ≧２ｆ_０の場合には、被帯電体の固有振動数（ｆ_１）が、（２ｆ_０）と（３ｆ_０）の中間の周波数で帯電するようにしたので、帯電部材が振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
請求項２の発明によれば、周波数（ｆ_０）の振動電圧を有する帯電部材によって、固有振動数（ｆ_１）を有する被帯電体を、調整手段を用いた調整によって被帯電体の長さ（ｌ）を変更して固有振動数（ｆ_１）を調整出来るようにしたので、簡単な調整で、帯電部材が振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
請求項３の発明によれば、周波数（ｆ_０）の振動電圧を有する帯電部材によって、固有振動数（ｆ_１）を有する被帯電体を、調整手段による調整によって被帯電体の長さ（ｌ）の変更で固有振動数（ｆ_１）を調整出来るようにして、ｆ_１ ≦２ｆ_０の場合に被帯電体の固有振動数（ｆ_１）を、ｆ_１＝（ｆ_０＋２ｆ_０）／２に、ｆ_１ ≧２ｆ_０の場合に被帯電体の固有振動数（ｆ_１）を、ｆ_１＝（２ｆ_０＋３ｆ_０）／２になるように帯電させたので、簡単な調整で帯電部材が振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に確実に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
請求項４の発明によれば、請求項１、２又は３において、帯電部材と非帯電体とを接触させるようにしたので、帯電部材が低い振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
【００１９】
請求項５の発明によれば、請求項１、２又は３において、帯電部材が被帯電体表面を損傷することなく振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
請求項６の発明によれば、請求項１、２、３、４、又は５において、帯電部材を帯電ローラとしたので、帯電ローラが振動電圧を印加して被帯電体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
請求項７の発明によれば、請求項１、２、３、４、５又は６において、被帯電体を像担持体としたので、帯電部材が振動電圧を印加して像担持体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を提供することが出来るようになった。
請求項８の発明によれば、周波数（ｆ_０）の振動電圧を有する帯電ローラによって、固有振動数（ｆ_１）を有する像担持体を、ｆ_１ ≦２ｆ_０の場合の像担持体の固有振動数（ｆ_１）は、帯電ローラの振動電圧の周波数（ｆ_０）と（２ｆ_０）の中間の周波数になるように、ｆ_１ ≧２ｆ_０の場合の像担持体の固有振動数（ｆ_１）は、（２ｆ_０）と（３ｆ_０）の中間の周波数で帯電するようにしたので、帯電ローラが振動電圧を印加して像担持体を帯電する際の、異音の発生を容易に防止すると共に軽量で低コストの帯電装置を使用して画像を形成する画像形成装置を提供することが出来るようになった。
【図面の簡単な説明】
【図１】本発明の実施の形態例の帯電装置の要部を説明する説明図である。
【図２】本発明の実施の形態例の画像形成装置の要部を説明する説明図である。
【符号の説明】
１帯電部材、１ａ帯電ローラ、２被帯電体、２ａ像担持体、２ｂシリンダ、２ｃ感光層、３調整手段、３ａ送り螺子、３ａ１螺子部、３ａ２螺子部、３ｂ調整部材、４支持部材、４ａ一方側軸受、４ａ_１支持部、４ａ_２螺子部、４ｂ他方側軸受、４ｂ_１支持部、４ｂ_２螺子部、５帯電装置、６露光手段、７現像手段、８駆動力伝達用歯車、９高圧電源、１０転写手段、１１定着手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a charging device and an image forming apparatus using the charging device. More specifically, a charging device that charges a member to be charged by applying a vibration voltage to the member to be charged by a charging member, and a copier, printer, facsimile machine using the electrophotographic method using the charging device, or a complex machine thereof. It is about.
[0002]
[Prior art]
As a conventional charging device and an image forming apparatus using the charging device, when applying a vibration voltage to a charged body while a charging member is in contact with or separated from the charged body, the frequency range or spatial frequency of the vibrating electric field Also known is a technique for uniformly charging the charged body and reducing the generation of ozone and vibration noise by specifying the moving speed of the charged body and the logarithmic attenuation rate of the vibration of the substrate. (See Japanese Patent Laid-Open Nos. 3-100694, 3-100675, Japanese Patent Laid-Open No. 3-101764, Japanese Patent Laid-Open No. 4-67072, etc.).
When applying an oscillating voltage to an object to be charged, the mass of the object to be charged is increased or a load is applied by a heavy object in order to prevent the object to be charged from vibrating and generating abnormal noise due to charging noise. There are also known techniques for reducing deformation caused by vibration of the charged body (see Japanese Patent Laid-Open Nos. 5-35048, 5-35051, and 8-179656, etc.).
However, in these prior arts, not only an increase in weight but also a problem of high cost has arisen in order to prevent the generation of abnormal noise due to the charging sound generated by the vibration of the charged body.
In addition, in order to prevent the generation of abnormal noise due to the charged sound when the charged body vibrates, the rigidity of the charged body is increased by adjusting the Young's modulus (longitudinal elastic modulus) and the thickness of the charged body. A technique for reducing the deformation due to the vibration is also known, but the cost is high as described above (see Japanese Patent Laid-Open No. 5-35050).
Therefore, the conventional charging device and the image forming apparatus using the charging device are charged with the abnormal sound due to the charging sound when the charged body vibrates when the charged body is charged by applying the vibration voltage from the charging member. In order to prevent the occurrence, if a weight for vibration control is used, not only the weight increases, but also a problem that the cost increases is caused.
[0003]
[Problems to be solved by the invention]
The conventional charging device and the image forming apparatus using the charging device described above generate abnormal noise due to the charging sound caused by the vibration of the charged body when the charging member applies the vibration voltage to charge the charged body. If a vibration damping weight is used to prevent this, not only the weight increases but also the cost increases.
Therefore, an object of the present invention is to solve such problems. That is, it is possible to easily prevent the generation of abnormal noise when a charging member applies an oscillating voltage to charge an object to be charged, and to provide a lightweight and low-cost charging device and an image forming apparatus using the charging device. It is aimed at that.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, a first aspect of the present invention is a charging device for applying a vibration voltage to a member to be charged by a charging member to charge the member to be charged, and having a vibration voltage having a frequency (f ₀ ). And a body to be charged having a natural frequency (f ₁ ), and a distance between support points of a support member that is fitted into each end opening of a cylinder constituting the body to be charged and supports the inside of the opening. Adjusting means for adjusting the natural frequency (f ₁ ) by changing the length (l) of the charged body to be charged, and the natural vibration of the charged body when f ₁ ≦ 2f ₀ The number (f ₁ ) is a frequency having an intermediate value between the frequency (f ₀ ) and (2f ₀ ) of the vibration voltage of the charging member, and the natural frequency (f of the charged body when f ₁ ≧ 2f ₀ is satisfied. ₁ ) by setting the frequency to a value intermediate between (2f ₀ ) and (3f ₀ ) It is characterized by preventing the occurrence.
According to a second aspect of the present invention, in the charging device according to the first aspect, the adjusting member supports a member to be charged having a natural frequency (f ₁ ) to which a vibration voltage having a frequency (f ₀ ) is applied by the charging member. The length (l) of the member to be charged is changed by moving the support position of the supporting member to change the natural frequency (f ₁ ) of the member to be charged when f ₁ ≦ 2f ₀ to f ₁ = (f ₀ + 2f ₀ ) / 2, and when f ₁ ≧ 2f ₀ , the natural frequency (f ₁ ) of the charged body is such that f ₁ = (2f ₀ + 3f ₀ ) / 2. The natural frequency (f ₁ ) of the member to be charged is adjusted to prevent the generation of abnormal noise.
According to a third aspect of the present invention, in the charging device according to the first or second aspect, the oscillating voltage is applied in a state where the charging member and the member to be charged are in contact with each other.
According to a fourth aspect of the present invention, in the charging device according to the first or second aspect, the vibration voltage is applied in a state where the charging member and the member to be charged are in a non-contact state.
According to a fifth aspect of the present invention, in the charging device according to the first, second, third, or fourth aspect, the charging member is a charging roller.
According to a sixth aspect of the present invention, in the charging device according to the first, second, third, fourth, or fifth aspect, the member to be charged is an image carrier.
The invention according to claim 7 is formed by the charging device, an exposure unit that forms an electrostatic latent image by exposing a charged object uniformly charged by a charging member of the charging device, and the exposure unit. Developing means for developing an electrostatic latent image to form a toner image, and the charging device includes the charging device according to claim 1, 2, 3, 4, 5, or 6. And
[0005]
[Action]
The charging apparatus configured as described above and the image forming apparatus using the charging apparatus have a natural frequency (f ₁ ) according to claim 1 due to a charging member having an oscillating voltage having a frequency (f ₀ ). The charged body can be adjusted by adjusting means so that the natural frequency (f ₁ ) can be adjusted by changing the length (l) of the charged body, and the charged body in the case of f ₁ ≦ 2f _0. natural frequency (f ₁₎ is such that the intermediate frequency of the oscillating voltage of said charging member and _{_{(f 0) (2f 0)}} , intrinsic of the member to be charged in the case of f ₁ ≧ 2f ₀ Since the frequency (f ₁ ) is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ), the charging member applies a vibration voltage and the object to be charged is easily adjusted. A lightweight, low-cost charging device that easily prevents abnormal noise when charging Can be provided.
[0006]
According to a second aspect of the present invention, a charging member having a natural frequency (f ₁ ) is changed by a charging member having an oscillating voltage having a frequency (f ₀ ) by changing the length (l) of the charged body by an adjusting means. The natural frequency (f ₁ ) can be adjusted, and when f ₁ ≦ 2f ₀ , the natural frequency (f ₁ ) of the charged body is set to f ₁ = (f ₀ + 2f ₀ ) / 2. In the case of f ₁ ≧ 2f _0, the charged member is charged with the natural frequency (f ₁ ) of f ₁ = (2f ₀ + 3f ₀ ) / 2. When charging the object to be charged by applying an oscillating voltage, it is possible to easily and surely prevent the generation of abnormal noise and to provide a charging device that is light in weight and low in cost.
According to a third aspect of the present invention, an object to be charged having a natural frequency (f ₁ ) in contact with the charging member is charged by the charging member having an oscillating voltage having a frequency (f ₀ ), and the object to be charged when f ₁ ≦ 2f ₀ is satisfied. The charged body in the case of f ₁ ≧ 2f ₀ so that the natural frequency (f ₁ ) of the charged body is an intermediate frequency between the vibration voltage frequency (f ₀ ) and (2f ₀ ) of the charging member. The natural frequency (f ₁ ) is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ), so that the charging member applies a low vibration voltage to charge the object to be charged. Thus, it is possible to easily prevent the generation of abnormal noise and to provide a lightweight and low-cost charging device.
[0007]
In a fourth aspect of the present invention, an object to be charged having a natural frequency (f ₁ ) separated from the charging member by a charging member having an oscillating voltage having a frequency (f ₀ ) is obtained when f ₁ ≦ 2f ₀ . The natural frequency (f ₁ ) of the member to be charged is the object to be charged in the case of f ₁ ≧ 2f ₀ so that the frequency (f ₀ ) and (2f ₀ ) of the vibration voltage of the charging member are intermediate. The natural frequency (f ₁ ) of the charged body is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ), so that the charging member does not damage the surface of the body to be charged. It is possible to easily prevent the generation of abnormal noise when charging the charged body by applying, and to provide a lightweight and low-cost charging device.
According to a fifth aspect of the present invention, a charged body having a natural frequency (f ₁ ) is charged by a charging roller having an oscillating voltage having a frequency (f ₀ ), and the natural frequency of the charged body when f ₁ ≦ 2f ₀ is satisfied. (f ₁₎ is such that the intermediate frequency of the oscillating voltage of the charging roller frequency (f ₀₎ and _{_{(2f 0), f 1 ≧}} 2f natural frequency of the member to be charged in the case of ₀ (f ₁ ) is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ). Therefore, the charging roller applies an oscillating voltage to charge the object to be charged. It is possible to provide a charging device that can be easily prevented and that is light in weight and low in cost.
[0008]
In the sixth aspect, by a charging member having an oscillating voltage of a frequency (f _0), the image bearing member having a natural frequency (f _1), the natural frequency of the image carrier in the case of f ₁ ≦ 2f ₀ (F ₁ ) is an intermediate frequency between the frequency (f ₀ ) and (2f ₀ ) of the vibration voltage of the charging member, so that the natural frequency (f of the image carrier when f ₁ ≧ 2f ₀ is satisfied. ₁ ) makes it easy to generate abnormal noise when the charging member charges the image carrier by applying an oscillating voltage so as to be charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ). It is possible to provide a charging device that is light and low in cost.
In the claims 7, by a charging roller having an oscillating voltage of a frequency (f _0), the image bearing member having a natural frequency (f _1), the natural frequency of the image carrier in the case of f ₁ ≦ 2f ₀ (F ₁ ) is the frequency between the frequency (f ₀ ) and (2f ₀ ) of the vibration voltage of the charging roller, so that the natural frequency (f of the image carrier when f ₁ ≧ 2f ₀ is satisfied. ₁ ) is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ), so that the charging roller applies an oscillating voltage to charge the image carrier to generate abnormal noise. It is possible to provide an image forming apparatus that can easily prevent and form an image using a light-weight and low-cost charging device.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of the configuration of a charging device according to an embodiment of the present invention. This charging device is used for image forming such as a copying machine, a printer, a facsimile machine, or a composite machine using an electrophotographic system. A charging roller 1a, which is a charging member 1 having an oscillating voltage of frequency (f ₀ ) used in the apparatus, is in contact with an image carrier 2a, which is a charged body 2 having a natural frequency (f ₁ ). The image bearing member 2a is charged by applying a vibration voltage having a frequency (f ₀ ).
Although not shown, the frequency of the charging roller 1a having a vibration voltage (f _0), a non-contact state of being spaced from the image bearing member 2a having a natural frequency (f _1), the frequency (f ₀₎ Alternatively, the image carrier 2a may be charged by applying the vibration voltage. In this case, the surface of the image carrier 2a can be prevented from being damaged by contact.
The applied voltage at which the charging roller 1a charges the image carrier 2a is, for example, a DC voltage of −800 V, an AC voltage peak-to-peak voltage of 2000 V, and a frequency (f ₀ ) of 550 Hz.
The image carrier 2a is obtained by applying a 20 μm-thick 0PC photosensitive layer 2c to the surface of a hollow cylindrical cylinder 2b, and is supported by fitting support members 4 into the openings at both ends of the cylinder 2b. doing. The support member 4 has a one-side bearing 4a having a driving force transmission gear 8 on the outer peripheral surface, made the other side bearing 4b, whereas the support portion 4a ₁ located at the inner end of the side bearing 4a, the other side bearing 4b The inner peripheral surface of the cylinder 2b is supported by the outer peripheral surface of the support portion 4b ₁ located at the inner end of the cylinder 2b.
[0010]
The one-side bearing 4a and the other-side bearing 4b that constitute the support member 4 are made of a resin such as polycarbonate, for example, so that it is possible to provide a low-cost charging device that is lighter and more productive. One side bearing 4a supporting portions 4a ₁ and the support portion 4b ₁ of the other side bearing 4b of the is temporarily fixed movably in the axial direction in the axial direction end sides in the opening by respective light press-fitting of the cylinder 2b. The adjusting means 3 is means for moving the bearings 4a and 4b in equal distances in and out of the axial direction in synchronization. Alternatively, the bearings 4a and 4b may be fixed at appropriate positions in the cylinder 2b by adhesion or the like. The cylinder 2b is made of a metal material such as an aluminum material, for example, and has an outer diameter of 30 mm, a thickness of 0.75 mm, a length of 260 mm, and is transmitted through the driving force transmission gear 8 (not shown). Is driven to rotate at a peripheral speed of 90 mm / sec.
The natural frequency (f ₁ ) of the image carrier 2a, which is the charged body 2, is determined by the shape, weight, etc. of the cylinder 2b, and is obtained by the following equation.
(F ₁ ) = λ ² / 2πl ² · (EI / Aρ) ^1/2
Λ is the frequency coefficient, E is the Young's modulus of aluminum, 6.86 × 10 ¹⁰ N / m ² , I is the secondary moment of section, A is the cross-sectional area, ρ is the specific gravity of aluminum, 2800 Kg / m ³ , λ Is λ = π when supported at both ends and assumed to be primary vibration.
[0011]
That is, since the natural frequency (f ₁ ) of the image carrier 2a is 1190 Hz and the frequency (f ₀ ) of the voltage applied to the charging roller 1a is 550 Hz, f ₁ (1190 Hz) is twice that of f ₀ . The value is close to 1100 Hz. That is, the natural frequency (f ₁ ) of the image carrier 2a resonates with respect to the frequency (f ₀ ) of the voltage applied to the charging member 1 and the frequency n (f ₀ ) that is an integral multiple of the frequency (f ₀ ). Occurs as an abnormal sound.
[0012]
On the other hand, in this embodiment, when f ₁ ≧ 2f ₀ , the one-side bearing 4a (support portion 4a ₁ ) and the other-side bearing 4b (support portion 4b) that support the inside of one end opening of the cylinder 2b. ₁ ) is moved from the both ends of the cylinder 2b by an equal distance in the direction indicated by the arrows A or B, respectively, so that the distance between the support points between the support portions 4a ₁ and 4b ₁ , that is, the support By changing the length (l) of the image carrier 2a determined by the distance between the left end surface of the portion 4a _{1 and} the right end surface of the support portion 4b ₁ to 240 mm, the natural frequency of the image carrier 2a ( f ₁ ) can be changed to 1400 Hz, and the frequency can be brought closer to the intermediate value farthest from the double frequency and triple frequency applied to the charging roller 1a. That is, the natural frequency (f ₁ ) is set to an intermediate frequency adjacent to (double frequency 1100 Hz + triple frequency 1650 Hz) / 2 = 1375 Hz so that abnormal sound due to resonance and resonance does not occur, thereby generating abnormal noise. It has become possible to provide a charging device that prevents the above-described problem.
That is, this embodiment is characterized in that the natural frequency (f ₁ ) of the image carrier 2a is configured to satisfy f ₁ = (2f ₀ + 3f ₀ ) / 2 when f ₁ ≧ 2f _0. Is.
[0013]
Next, when the length of the cylinder 2b is 340 mm, the natural frequency (f ₁ ) of the image carrier 2a is determined by the structure of the cylinder 2b and is obtained by the following equation.
(F ₁ ) = λ ² / 2π l ² · (EI / Aρ ) ^1/2
Where λ is the frequency coefficient, E is the Young's modulus of aluminum, 6.86 × 10 ¹⁰ N / m ² , I is the secondary moment of section, A is the cross-sectional area, ρ is the specific gravity of aluminum, 2800 Kg / m ³ , λ is λ = π when it is supported at both ends and is a primary vibration.
According to this equation, the natural frequency (f ₁ ) of the image carrier 2a is 700 Hz, and since this value is close to 550 Hz of the frequency (f ₀ ) of the voltage applied to the charging roller 1a, When the natural frequency (f ₁ ) of the image carrier 2a is close to the frequency (f ₀ ) of the voltage and the frequency n (f ₀ ) that is an integral multiple of the frequency (f ₀ ), resonance occurs and the charging sound due to resonance is generated as an abnormal sound. .
[0014]
On the other hand, in another embodiment of the present invention, when f ₁ ≦ 2f ₀ , the one-side bearing 4a (support portion 4a ₁ ) and the other-side bearing 4b (support portion 4b ₁ ) that support the cylinder 2b. Is moved equidistantly from the both ends of the cylinder 2b in the direction indicated by the arrow A or B in the direction shown in the figure, and the distance between the support points of the support 4a ₁ and the support 4b ₁ , ie, the length of the image carrier 2a. The length (l) is 310 mm. Then, the natural frequency (f ₁ ) of the image carrier 2a is 836 Hz, which is a frequency that is the farthest from the 1st frequency and the 2nd frequency of the applied voltage of the charging member 1. That is, by setting the natural frequency (f ₁ ) of the image carrier 2a to an intermediate frequency adjacent to (1 × frequency 550 Hz + 2 × frequency 1100 Hz) / 2 = 825 Hz and causing no abnormal sound due to resonance or resonance, It is possible to easily prevent the generation of abnormal noise and to provide a lightweight and low-cost charging device. That is, this embodiment is characterized in that the natural frequency (f ₁ ) of the image carrier 2a is f ₁ = (f ₀ + 2f ₀ ) / 2 when f ₁ ≦ 2f _0. It is.
[0015]
In the above embodiment, the case where the cylinder 2b is made of an aluminum material and has an outer diameter of 30 mm has been described. However, as in the other cases, the natural frequency (f ₁ ) of the image carrier 2a is 60 mm. Further, by making the frequency adjacent to each integer multiple frequency of the voltage applied to the charging roller 1a and the intermediate frequency that does not generate abnormal noise due to resonance and resonance, the generation of abnormal noise is easily prevented and light weight is achieved. And a low-cost charging device can be provided.
The adjusting means 3 includes a feed screw 3a that is threadedly engaged with the female screw portions 4a ₂ and 4b ₂ formed in the shaft holes of the bearings 4a and 4b, and an adjustment provided at one end of the feed screw 3a. become from the member 3b (operating knob), feed screw 3a is a direction twisted provided on both end sides of the reverse threaded portion 3a1 and the screw portion 3a2 of each whereas the side bearing 4a female screw portion 4a ₂ and the other side bearing 4b The length (l) of the image carrier 2a can be changed by screwing into the female screw portion 4b ₂ and manually or automatically turning the adjusting member 3b integrated with the feed screw 3a. Yes.
[0016]
In the present embodiment, the natural frequency at which the vibration voltage of the frequency (f ₀ ) is applied by the charging roller 1a by rotating the adjustment member 3b of the adjustment means 3 in a forward or reverse direction by a predetermined angle (number of times). The support positions of the support portion 4a ₁ and the support portion 4b ₁ of the support member 4 that supports the image carrier 2a having (f ₁ ) can be moved, and the length of the image carrier 2a ( 1), when f ₁ ≦ 2f ₀ , the natural frequency (f ₁ ) of the image carrier 2a is set to f ₁ = (f ₀ + 2f ₀ ) / 2, and f ₁ ≧ 2f ₀ Then, the natural frequency (f ₁ ) of the image carrier 2a is adjusted so that the natural frequency (f ₁ ) of the image carrier 2a is f ₁ = (2f ₀ + 3f ₀ ) / 2, and resonance occurs. By using an intermediate frequency that does not generate abnormal noise due to resonance, abnormal noise is prevented. Rukoto is made to be able to.
[0017]
FIG. 2 is a schematic configuration diagram when the charging device of the present invention is applied to a copying machine, a printer, a facsimile machine or a complex machine using the electrophotographic method, and the frequency (f ₀ ) of the high-voltage power source 9 is shown. The charging roller 1a having an oscillating voltage applies an oscillating voltage having a frequency (f ₀ ) to the image carrier 2a having the natural frequency (f ₁ ) to charge the image carrier 2a as described above. It is like that.
The image bearing member 2a uniformly charged by the charging roller 1a is exposed by the exposure means 6 to form an electrostatic latent image, and then the electrostatic latent image formed by the exposure means 6 is developed by the developing means 7. The developed toner image is transferred onto the transfer paper (P) by the transfer means 10, and the transfer paper (P) is discharged out of the apparatus and stored after the toner image is fixed by the fixing means 11. .
Accordingly, there is provided an image forming apparatus capable of easily preventing abnormal noise when the charging roller 1a applies an oscillating voltage to charge the image carrier 1a, and forming an image by charging with light weight at low cost. I can do it now.
[0018]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the charging member having the natural frequency (f ₁ ) is obtained by the charging member having the oscillating voltage of the frequency (f ₀ ), when f ₁ ≦ 2f ₀ When f ₁ ≧ 2f ₀ so that the natural frequency (f ₁ ) of the member to be charged is an intermediate frequency between the vibration voltage frequency (f ₀ ) and (2f ₀ ) of the charging member, Since the natural frequency (f ₁ ) of the charged body is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ), the charging member applies a vibration voltage to charge the charged body. Thus, it is possible to easily prevent the generation of abnormal noise and to provide a lightweight and low-cost charging device.
According to the second aspect of the present invention, the charged body having the natural frequency (f ₁ ) is adjusted by the charging member having the oscillating voltage of the frequency (f ₀ ), and the length of the charged body is adjusted by adjusting the adjusting means. Since the natural frequency (f ₁ ) can be adjusted by changing (l), it is possible to adjust the natural frequency (f ₁ ) with a simple adjustment to generate abnormal noise when the charging member applies the vibration voltage to charge the object to be charged. It has become possible to provide a charging device that can be easily prevented and that is light in weight and low in cost.
According to the third aspect of the present invention, the charged member having the natural frequency (f ₁ ) is adjusted by the charging member having the oscillating voltage of the frequency (f ₀ ), and the length (l of the charged member is adjusted by the adjusting means. ), The natural frequency (f ₁ ) can be adjusted, and when f ₁ ≦ 2f ₀ , the natural frequency (f ₁ ) of the charged body is expressed as f ₁ = (f ₀ + 2f ₀ ) / 2. In addition, since the natural frequency (f ₁ ) of the charged object is charged so that f ₁ = (2f ₀ + 3f ₀ ) / 2 when f ₁ ≧ 2f ₀ , the charging member can be easily adjusted. It has become possible to provide a charging device that can easily and reliably prevent the generation of abnormal noise when charging an object to be charged by applying an oscillating voltage, and that is light in weight and low in cost.
According to a fourth aspect of the present invention, since the charging member and the non-charged body are brought into contact with each other in the first, second, or third aspect, the charging member applies a low oscillating voltage to charge the object to be charged. Thus, it is possible to easily prevent the generation of abnormal noise and to provide a lightweight and low-cost charging device.
[0019]
According to a fifth aspect of the invention, in the first, second, or third aspect, abnormal noise is generated when the charging member charges the charged body by applying an oscillating voltage without damaging the surface of the charged body. It has become possible to provide a charging device that can be easily prevented and that is light in weight and low in cost.
According to the invention of claim 6, in claim 1, 2, 3, 4, or 5, since the charging member is a charging roller, the charging roller applies a vibration voltage to charge the object to be charged. It is possible to easily prevent the generation of abnormal noise and to provide a lightweight and low-cost charging device.
According to the seventh aspect of the invention, in the first, second, third, fourth, fifth or sixth aspect, since the member to be charged is the image carrier, the charging member applies the vibration voltage to charge the image carrier. At the same time, it is possible to easily prevent the generation of abnormal noise and to provide a lightweight and low-cost charging device.
According to the invention of claim 8, by a charging roller having an oscillating voltage of a frequency (f _0), the image bearing member having a natural frequency (f _1), specific image bearing member in the case of f ₁ ≦ 2f ₀ frequency _{(f 1),} the frequency of the oscillating voltage of the charging roller _{(f 0)} and (2f ₀₎ intermediate so that the frequency of the natural frequency of the image carrier in the case of _{f 1} ≧ 2f ₀ _(f ₁ ) is charged at an intermediate frequency between (2f ₀ ) and (3f ₀ ), so that it is easy to generate abnormal noise when the charging roller charges the image carrier by applying a vibration voltage. It is possible to provide an image forming apparatus that forms an image by using a charging device that is light in weight and low in cost.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a main part of a charging device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram illustrating a main part of an image forming apparatus according to an exemplary embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Charging member, 1a Charging roller, 2 To-be-charged body, 2a Image carrier, 2b Cylinder, 2c Photosensitive layer, 3 Adjustment means, 3a Feed screw, 3a1 Screw part, 3a2 screw part, 3b Adjustment member, 4 Support member, 4a One side bearing, 4a ₁ support part, 4a ₂ screw part, 4b The other side bearing, 4b ₁ support part, 4b ₂ screw part, 5 charging device, 6 exposure means, 7 developing means, 8 driving force transmission gear, 9 high pressure Power supply, 10 transfer means, 11 fixing means

Claims

In a charging device that applies a vibration voltage to a member to be charged by a charging member to charge the member to be charged, a charging member having a vibration voltage having a frequency (f ₀ ), and a member to be charged having a natural frequency (f ₁ ) And changing the length (l) of the body to be charged, which is determined by the distance between the support points of the support members that are fitted to both ends of the cylinder constituting the body to be charged and support the inside of the opening. And adjusting means for adjusting the natural frequency (f ₁ ), and when f ₁ ≦ 2f ₀ , the natural frequency (f ₁ ) of the member to be charged is set to the frequency of the vibration voltage of the charging member ( f ₀₎ and the frequency of the intermediate value _{_{(2f 0), f 1 ≧}} 2f natural frequency of the member to be charged when it is ₀ (f ₁₎ and (2f ₀₎ intermediate (3f ₀₎ A charging device that prevents occurrence of abnormal noise by setting a frequency of a value.

2. The charging device according to claim 1, wherein the adjusting means supports a supporting position of a supporting member that supports a member to be charged having a natural frequency (f ₁ ) to which an oscillating voltage having a frequency (f ₀ ) is applied by the charging member. By moving, the length (l) of the member to be charged is changed, and the natural frequency (f ₁ ) of the member to be charged when f ₁ ≦ 2f ₀ is set to f ₁ = (f ₀ + 2f _0). ) / 2, and the natural frequency (f ₁ ) of the member to be charged when f ₁ ≧ 2f ₀ is f ₁ = (2f ₀ + 3f ₀ ) / 2. A charging device characterized by adjusting (f ₁ ) to prevent the generation of abnormal noise.

3. The charging device according to claim 1, wherein the oscillating voltage is applied in a state where the charging member and the member to be charged are in contact with each other.

3. The charging device according to claim 1, wherein the vibration voltage is applied in a state where the charging member and the member to be charged are in a non-contact state.

5. The charging device according to claim 1, wherein the charging member is a charging roller.

6. The charging device according to claim 1, wherein the member to be charged is an image carrier.

Developing the electrostatic latent image formed by the charging device, an exposure unit that exposes a charged object uniformly charged by a charging member of the charging device to form an electrostatic latent image, and the exposure unit; An image forming apparatus comprising: a developing unit that forms a toner image; and the charging device includes the charging device according to claim 1.