JPH04268574A - Contact electrostatic charging method - Google Patents

Abstract

PURPOSE:To prevent an electrostatic charging sound from being produced while maintaining the evening effect of electrostatic charging by impressing AC voltage in a contact electrostatic charging method in which a body to be electrostatically charged is uniformly electrostatically charged by impressing DC voltage and AC voltage on the electrostatic charging member. CONSTITUTION:A 1st conductive part 1a which comes in contact with a rotating photosensitive drum(body to be electrostatically charged) 2 directly or through a high resistance layer 1b, and a 2nd conductive part 1d which is close to the 1st conductive part 1a in a non-conducting state on the upstream side or/and the downstream side of the conductive part 1a in the rotating direction of the photosensitive drum and opposed to the photosensitive drum 2 in a non-contact state are provided, and only the DC voltage Vdc is impressed on the 1st conductive part 1a and the AC voltage Vac or the voltage obtained by superposing the AC voltage Vac on the DC voltage Vdc is impressed on the 2nd conductive part 1d.

Description

【発明の詳細な説明】[Detailed description of the invention]

【０００１】0001

【産業上の利用分野】本発明は、電圧を印加した帯電部
材を被帯電体に当接させ、両者を相対的移動させて被帯
電体を所定の極性・電位に帯電（除電も含む）する接触
帯電方法に関するものである。[Industrial Application Field] The present invention involves bringing a charging member to which a voltage is applied into contact with an object to be charged, and moving the two relative to each other to charge (including removing static electricity) the object to be charged to a predetermined polarity and potential. This invention relates to a contact charging method.

【０００２】0002

【従来の技術】例えば、電子写真装置（複写機・レーザ
ービームプリンタ・画像表示装置など）・静電記録装置
等の画像形成装置において、感光体・誘電体等の像担持
体（被帯電体）面を帯電処理する装置としては従来より
コロナ放電装置が広く利用されている。[Prior Art] For example, in image forming devices such as electrophotographic devices (copying machines, laser beam printers, image display devices, etc.) and electrostatic recording devices, image carriers (charged objects) such as photoreceptors and dielectric materials are used. Corona discharge devices have been widely used as devices for charging surfaces.

【０００３】コロナ放電装置は被帯電体面を所定の極性
・電位に均一に帯電処理する装置として有効である。し
かし、高圧電源を必要とする、帯電効率が低い、コロナ
放電により好ましくないオゾン等のコロナ生成物が比較
的多く発生する、放電ワイヤの汚れによる放電ムラの発
生などの問題を有している。A corona discharge device is effective as a device for uniformly charging the surface of an object to be charged to a predetermined polarity and potential. However, it has problems such as requiring a high-voltage power supply, low charging efficiency, relatively large amounts of undesirable corona products such as ozone generated by corona discharge, and uneven discharge due to dirt on the discharge wire.

【０００４】一方、前記のように電圧を印加した帯電部
材を被帯電体に接触させて被帯電体面を帯電処理する接
触帯電方法もしくは装置は、電源の低圧化が図れ、オゾ
ン等の発生は殆どない等の長所を有していることから、
上記コロナ放電装置に代わる帯電処理手段として注目さ
れ、その実用化研究が進められている（特開昭５７−１
７８２６７・５６−１０４３５１・５８−４０５６６・
５８−１３９１５６・５８−１５０９７５号公報等）。On the other hand, the contact charging method or device in which a charging member to which a voltage is applied is brought into contact with an object to be charged to charge the surface of the object to be charged as described above can reduce the voltage of the power source and generate almost no ozone or the like. Because it has the advantage of not having
It has attracted attention as a charging treatment means to replace the above-mentioned corona discharge device, and research into its practical use is progressing (Japanese Patent Laid-Open No. 57-1
78267・56-104351・58-40566・
58-139156, 58-150975, etc.).

【０００５】本出願人も、均一な帯電処理等を目的とし
て、帯電部材に対する印加電圧を直流電圧Ｖｄｃと交流
電圧Ｖａｃの重畳電圧（振動電圧）とすることを基本と
する接触帯電方法ないし装置の提案をしている（特開昭
６３−１４９６６８号・６３−１４９６６９号広報等）
。The present applicant has also developed a contact charging method or device which is based on applying a voltage to a charging member as a superimposed voltage (oscillating voltage) of a DC voltage Vdc and an AC voltage Vac for the purpose of uniform charging processing. We are making proposals (Japanese Patent Application Publication No. 63-149668 and 63-149669, etc.)
.

【０００６】具体的には図４に示すように被帯電体とし
ての例えば回転駆動される電子写真感光体ドラム２（以
下、感光ドラムと記す）に帯電部材としての例えばロー
ラ型の導電性部材１０（以下、帯電ローラと記す）を接
触させ、この帯電ローラ１０に電源１４により、直流電
圧Ｖｄｃと、感光体の帯電開始電圧の２倍以上のピーク
間電圧Ｖｐｐを有する交流電圧Ｖａｃとを重畳した電圧
を印加して帯電ローラ１０と感光ドラム２間に振動電界
を作用させることで感光ドラム２面を均一に帯電するこ
とができる。感光ドラム２の帯電電位は印加直流電圧に
よって決定される。交流電圧はその帯電電位の均し作用
をする。なお本例の帯電ローラ１０は、電圧の印加され
る導電性芯金１１と、該芯金に同心一体に金型成形等で
ローラ状に成形した導電性ゴムなどでできている低抵抗
層１２と、更にその外周に形成したトレジン等のナイロ
ンでできている高抵抗層１３とからなる複合層構造のも
のであり、感光ドラム２の回転に従動回転する。Specifically, as shown in FIG. 4, a rotationally driven electrophotographic photosensitive drum 2 (hereinafter referred to as a photosensitive drum) as an object to be charged, for example, and a roller-shaped conductive member 10 as a charging member. (hereinafter referred to as a charging roller) was brought into contact with the charging roller 10, and a DC voltage Vdc and an AC voltage Vac having a peak-to-peak voltage Vpp that is more than twice the charging start voltage of the photoreceptor were superimposed on the charging roller 10 by a power source 14. By applying a voltage and causing an oscillating electric field to act between the charging roller 10 and the photosensitive drum 2, the surface of the photosensitive drum 2 can be uniformly charged. The charged potential of the photosensitive drum 2 is determined by the applied DC voltage. The alternating voltage acts to equalize the charged potential. The charging roller 10 of this example includes a conductive core metal 11 to which a voltage is applied, and a low-resistance layer 12 made of conductive rubber or the like molded into a roller shape by molding or the like concentrically with the core metal. and a high-resistance layer 13 made of nylon such as resin formed on the outer periphery of the photosensitive drum 2. The photosensitive drum 2 rotates as the photosensitive drum 2 rotates.

【０００７】[0007]

【発明が解決しようとする課題】しかしながら、このよ
うに帯電部材１０に交流成分を含む電圧を印加して被帯
電体を接触帯電する手段の問題点として「帯電音」と呼
ばれる耳障りとなる振動騒音の発生が挙げられる。。[Problems to be Solved by the Invention] However, a problem with this method of contact charging the object to be charged by applying a voltage containing an alternating current component to the charging member 10 is that it produces an unpleasant vibration noise called "charging noise". The occurrence of .

【０００８】この帯電音の発生するメカニズムを図５を
用いて説明する。帯電部材１０には、交流電圧が印加さ
れているため、ある瞬間には、図５の（Ａ）中の破線で
示すように、被帯電体としての感光ドラム２の感光層２
ａを挟んで、帯電部材１０側にプラス、感光ドラム２の
ドラム基板２ｂ側にマイナスの電荷が誘起される。これ
らの電荷は互いに引き合うので、帯電部材表面は感光ド
ラムに引きつけられ、図中、実線の位置から破線の位置
に移動する。The mechanism by which this charging noise is generated will be explained with reference to FIG. Since an alternating current voltage is applied to the charging member 10, at a certain moment, as shown by the broken line in FIG.
A positive charge is induced on the charging member 10 side, and a negative charge is induced on the drum substrate 2b side of the photosensitive drum 2, with the distance a being sandwiched therebetween. Since these charges attract each other, the surface of the charging member is attracted to the photosensitive drum and moves from the position indicated by the solid line to the position indicated by the broken line in the figure.

【０００９】ついで、交流電界が逆転を始めると、帯電
部材１０のプラス電荷、ドラム基板２ｂ側のマイナス電
荷はそれぞれ誘起してきた逆極性の電荷によって打ち消
され始める。そして交流電界がちょうどプラスからマイ
ナスに変わるときには、帯電部材１０上のプラス電荷と
ドラム基板２ｂ上のマイナス電荷は消滅する。その結果
、帯電部材１０の表面は図５の（Ｂ）中の破線で示す位
置に戻ることになる。Next, when the alternating current electric field starts to reverse, the positive charges on the charging member 10 and the negative charges on the drum substrate 2b begin to be canceled by the induced charges of opposite polarity. Then, when the AC electric field just changes from positive to negative, the positive charges on the charging member 10 and the negative charges on the drum substrate 2b disappear. As a result, the surface of the charging member 10 returns to the position shown by the broken line in FIG. 5(B).

【００１０】さらに、交流電界がマイナスのピークを向
かえるときには、図５の（Ｃ）に示されるように、帯電
部材１０側にはマイナス、ドラム基板２ｂ側にはプラス
の電荷が誘起される。したがって帯電部材１０は再び実
線の位置から破線の位置にまで移動することになる。Furthermore, when the AC electric field reaches a negative peak, negative charges are induced on the charging member 10 side and positive charges on the drum substrate 2b side, as shown in FIG. 5C. Therefore, the charging member 10 moves again from the position indicated by the solid line to the position indicated by the broken line.

【００１１】以上の現象が繰り返し行なわれるため、帯
電部材１０に交流電圧を印加すると振動を始め、その結
果、帯電音が発生するものと考えられる。Since the above phenomenon occurs repeatedly, it is thought that when an alternating current voltage is applied to the charging member 10, it begins to vibrate, and as a result, charging noise is generated.

【００１２】交流電圧の周波数をｆ、帯電部材１０の振
動周波数をＦとすると、上記の説明で明らかなように、
交流電圧の１周期の間に帯電部材１０は２回振動するこ
とになり、両者ｆとＦの間には次の関係がある。Assuming that the frequency of the AC voltage is f and the vibration frequency of the charging member 10 is F, as is clear from the above explanation,
The charging member 10 vibrates twice during one cycle of the AC voltage, and the following relationship exists between f and F.

【００１３】２ｆ（Ｈｚ）＝Ｆ（ｃ／ｓ　）そこで、印
加交流成分のピーク間電圧Ｖｐｐを帯電開始電圧の２倍
の値より小さくすれば、帯電音をかなり改善することが
できる。しかしながら、その場合、感光ドラム２上には
、均一な帯電を得ることが困難となり、斑点状の帯電ム
ラを生じることになる。これは、帯電部材１０と感光ド
ラム２との接触面には微視的には凹凸があり、理想的な
接着面が得られないためである。2f (Hz)=F (c/s) Therefore, if the peak-to-peak voltage Vpp of the applied AC component is made smaller than twice the charging start voltage, charging noise can be considerably improved. However, in that case, it becomes difficult to obtain uniform charging on the photosensitive drum 2, resulting in spot-like charging unevenness. This is because the contact surface between the charging member 10 and the photosensitive drum 2 is microscopically uneven, making it impossible to obtain an ideal bonding surface.

【００１４】ここで、ピーク間電圧を下げると言うこと
は、交流電圧を印加することで均一な帯電を行なう、い
わゆる電位の「均し効果」がなくなることを示している
。斑点状の帯電ムラが生じた感光ドラム表面に通常の電
子写真画像形成プロセスを適用しても、出力画像は斑点
状ムラに対応した斑点状の黒点画像になり、高品位な画
像を得ることはできない。[0014] Here, lowering the peak-to-peak voltage means that the so-called "leveling effect" of the potential, which achieves uniform charging by applying an alternating current voltage, is eliminated. Even if a normal electrophotographic image forming process is applied to the surface of a photosensitive drum with spotty charging unevenness, the output image will be a spotty black dot image corresponding to the spotty unevenness, making it impossible to obtain a high-quality image. Can not.

【００１５】また、上記帯電音を解消すべく、感光ドラ
ム２の内部に、ゴムなどでできた防振部材を入れること
が提案されているが、感光ドラム２の変形、重量化、製
造コストの点で何れも未だ実用化されていない。Furthermore, in order to eliminate the above-mentioned charging noise, it has been proposed to insert a vibration isolating member made of rubber or the like inside the photosensitive drum 2, but this method causes deformation of the photosensitive drum 2, weight increase, and manufacturing cost. None of these methods have yet been put into practical use.

【００１６】本発明は同じく帯電部材に直流電圧と交流
電圧とを印加して被帯電体面を均一に接触帯電させるも
のであるが、帯電音の発生はなくするように工夫した接
触帯電方法を提供するものである。The present invention also provides a contact charging method that applies a DC voltage and an AC voltage to a charging member to uniformly contact charge the surface of the object to be charged, but is devised to eliminate the generation of charging noise. It is something to do.

【００１７】[0017]

【課題を解決するための手段】本発明は、被帯電体に直
接または抵抗層を介して接触して被帯電体と相対移動す
る第１の導電部と、該第１の導電部の前記被帯電体との
相対移動方向の上流側または下流側或いは上流側と下流
側とに該第１の導電部に非導通に近接させて且つ被帯電
体とは非接触に対向させて第２の導電部を具備させ、前
記第１の導電部には直流電圧のみを、前記第２の導電部
には交流電圧又は交流電圧と直流電圧の重畳電圧を印加
して被帯電体面を接触帯電することを特徴とする接触帯
電方法、である。[Means for Solving the Problems] The present invention provides a first conductive portion that contacts an object to be charged directly or through a resistance layer and moves relative to the object to be charged; A second conductive portion is disposed adjacent to the first conductive portion in a non-conducting manner on the upstream side or downstream side in the direction of relative movement with respect to the charged body, or on the upstream side and the downstream side, and is opposed to the charged body without contacting the first conductive portion. The surface of the object to be charged is contact-charged by applying only a DC voltage to the first conductive part and applying an AC voltage or a superimposed voltage of an AC voltage and a DC voltage to the second conductive part. This is a contact charging method characterized by:

【００１８】[0018]

【作用】（１）即ち、直流電圧と交流電圧を印加する帯
電部材を上記のように被帯電体に接触させた第１の導電
部と、被帯電体に非接触の第２の導電部の２部構成とな
し、第１の導電部には直流電圧のみを、第２の導電部に
は交流電圧（直流電圧を含んでもよい）を分けて印加す
る構成でも、被帯電体にはこれに接触の第１の導電部に
印加した直流電圧が作用して被帯電体の帯電電位はこの
印加直流電圧によって決定されるとともに、非接触とし
た第２の導電部に印加した交流電圧の電界が作用して、
被帯電体に接触させた帯電部材に交流電圧を印加した場
合と同様に、被帯電体に対して交流電流が流れて交流電
流による被帯電体表面電位の均らし効果が認められ、被
帯電体に接触した帯電部材に直流電圧と交流電圧との重
畳電圧を印加した場合と同様の均一帯電効果が維持され
る。[Function] (1) That is, the first conductive part has a charging member that applies DC voltage and AC voltage in contact with the object to be charged as described above, and the second conductive part does not contact the object to be charged. Even with a two-part configuration in which only DC voltage is applied to the first conductive part and AC voltage (which may include DC voltage) separately applied to the second conductive part, the object to be charged is The DC voltage applied to the first conductive part in contact acts, and the charged potential of the charged object is determined by this applied DC voltage, and the electric field of the AC voltage applied to the second conductive part in non-contact is act,
Similar to when an AC voltage is applied to a charging member that is in contact with a charged object, an alternating current flows to the charged object, and the alternating current has an effect of leveling the surface potential of the charged object. The same uniform charging effect as when a superimposed voltage of DC voltage and AC voltage is applied to the charging member in contact with the charging member is maintained.

【００１９】（２）この場合、被帯電体に接触させた第
１の導電部は印加電圧が直流電圧のみであるから、この
第１の導電部は被帯電体に対して印加電圧にもとづく振
動現象はなく、そして交流電圧を印加した第２の導電部
は被帯電体に対して非接触であるから、被帯電体との接
触振動にもとづく帯電音は発生しない。(2) In this case, since the voltage applied to the first conductive portion in contact with the charged object is only a DC voltage, the first conductive portion vibrates against the charged object based on the applied voltage. There is no such phenomenon, and since the second conductive portion to which the AC voltage is applied is not in contact with the object to be charged, no charging noise is generated due to contact vibration with the object to be charged.

【００２０】（３）なお第２の導電部に印加する交流電
圧の波形としては正弦波、矩形波、三角波等適宜使用可
能である。また例えば直流電源をオン・オフすることに
よって形成された矩形波の電圧も含む。このように交流
電圧は周期的にその電圧値が変化するバイアスが使用出
来る。(3) Note that as the waveform of the AC voltage applied to the second conductive part, a sine wave, a rectangular wave, a triangular wave, etc. can be used as appropriate. It also includes, for example, a rectangular wave voltage formed by turning on and off a DC power source. In this way, a bias whose voltage value changes periodically can be used as an AC voltage.

【００２１】[0021]

【実施例】〈実施例１〉（図１）図１は像担持体（被帯
電体）としての感光ドラム２を本発明の接触帯電方法を
用いて一次帯電処理するようにした電子写真プロセス利
用のレーザービームプリンタの一例の概略構成図である
。[Example] <Example 1> (Figure 1) Figure 1 shows the use of an electrophotographic process in which a photosensitive drum 2 as an image carrier (charged body) is subjected to primary charging treatment using the contact charging method of the present invention. 1 is a schematic configuration diagram of an example of a laser beam printer of FIG.

【００２２】感光ドラム２は矢示の時計方向に所定の周
速度（プロセススピード）で回転駆動される。The photosensitive drum 2 is rotated clockwise as indicated by an arrow at a predetermined circumferential speed (process speed).

【００２３】１ａは第１の導電部であり。感光ドラム２
との対向面にトレジン等のナイロンからなる高抵抗層１
ｂを形成して該高抵抗層を介して感光ドラム２面に所定
の押圧力をもって接触させて絶縁性支持体１ｃに取付け
て配設した金属電極である。本実施例はステンレス等の
金属でできた幅４ｍｍ，厚さ０．５ｍｍの金属電極であ
る。この第１の導電部たる金属電極１ａに対して電源３
からマイナス１．１ＫＶの直流バイアスを印加した。高
抵抗層１ｂは感光体上にピンホール等の低耐圧欠陥部が
あっても電極板１ａからそのピンホール等に向かって火
花放電が発生しないように設けたものである。[0023] 1a is a first conductive part. Photosensitive drum 2
A high-resistance layer 1 made of nylon such as Trezin is placed on the opposite surface of the
This is a metal electrode which is attached to the insulating support 1c and brought into contact with the surface of the photosensitive drum 2 with a predetermined pressing force through the high resistance layer. In this embodiment, a metal electrode is made of metal such as stainless steel and has a width of 4 mm and a thickness of 0.5 mm. A power source 3 is connected to the metal electrode 1a serving as the first conductive portion.
A DC bias of -1.1 KV was applied. The high-resistance layer 1b is provided to prevent spark discharge from occurring from the electrode plate 1a toward the pinhole or the like even if there is a low breakdown voltage defect such as a pinhole on the photoreceptor.

【００２４】１ｄは第２の導電部であり、第１の導電部
１ａよりも感光ドラム回転方向上流側において該第１の
導電部１ａに近接させて且つ感光ドラム２には非接触に
感光ドラム２に対向させて絶縁性支持体１ｃに取り付け
て配設したステンレス等でできた金属電極であり、第１
の導電部１ａとは非導通である。この第２の導電部たる
金属電極１ｄは電源４からピーク間電圧Ｖｐｐが２．０
ｋＶ、周波数が６００Ｈｚの交流バイアスを印加した。Reference numeral 1d denotes a second conductive portion, which is disposed close to the first conductive portion 1a on the upstream side of the first conductive portion 1a in the rotational direction of the photosensitive drum and without contacting the photosensitive drum 2. It is a metal electrode made of stainless steel or the like, which is attached to an insulating support 1c facing the first
There is no conduction with the conductive portion 1a. The metal electrode 1d serving as the second conductive portion has a peak-to-peak voltage Vpp of 2.0 from the power source 4.
An alternating current bias of kV and a frequency of 600 Hz was applied.

【００２５】上記のように電圧を印加した第１と第２の
導電部１ａ・１ｄにより回転感光ドラム２面が接触帯電
方式で均一に一次帯電処理された。感光ドラム２の帯電
電位は第１の導電部１ａに印加される直流バイアスによ
って決定される。本実施例では上記の条件でマイナス５
５０Ｖの表面電位が得られた。As described above, the surface of the rotating photosensitive drum 2 was uniformly primary charged by the contact charging method by the first and second conductive parts 1a and 1d to which a voltage was applied. The charging potential of the photosensitive drum 2 is determined by the DC bias applied to the first conductive portion 1a. In this example, minus 5 under the above conditions.
A surface potential of 50V was obtained.

【００２６】交流電流は感光ドラム２に対して本実施例
では２２０μＡ流れ、交流電流による感光ドラム表面電
位の均し効果が認められた。In this example, an alternating current of 220 μA was applied to the photosensitive drum 2, and the effect of the alternating current on the surface potential of the photosensitive drum was observed.

【００２７】交流バイアスを印加した第２の導電部１ｄ
は感光ドラム２に非接触であり、感光ドラム２に接触の
第２の導電部１ａは直流バイアスのみの印加であるから
振動せず、帯電音は発生しない。[0027] Second conductive part 1d to which AC bias is applied
is not in contact with the photosensitive drum 2, and the second conductive portion 1a in contact with the photosensitive drum 2 receives only a DC bias, so it does not vibrate and generate no charging noise.

【００２８】上記のように均一に一次帯電処理された感
光ドラム２面に対してレーザービーム５による画像情報
走査露光、現像装置６によるトナー現像、形成トナー像
の転写ローラ８による転写材７に対する転写の工程が実
行され、トナー像転写を受けて感光ドラム２面から分離
された転写材７が不図示の定着装置へ導入されて画像形
成物（プリント）として出力される。トナー像転写後の
感光ドラム面はクリーニング装置で転写残りトナー等の
付着汚損物の除去がなされて清浄面化され、繰り返して
作像に供される。Image information is scanned and exposed by a laser beam 5 to the two surfaces of the photosensitive drum which have been uniformly primary charged as described above, toner development is performed by a developing device 6, and the formed toner image is transferred onto a transfer material 7 by a transfer roller 8. The steps are executed, and the transfer material 7 separated from the surface of the photosensitive drum 2 after the toner image transfer is introduced into a fixing device (not shown) and output as an image formed product (print). After the toner image has been transferred, the surface of the photosensitive drum is cleaned by a cleaning device to remove adhered contaminants such as residual toner, and is used repeatedly for image formation.

【００２９】図１の系の帯電装置を無響室にセットし、
前記の条件において発生する騒音をＩＳＯ７７７９の６
項に従い測定した。その結果、前述図４に示す従来装置
では５５ｄＢ近くあった騒音が３３ｄＢにまで小さくな
っていた。The charging device of the system shown in FIG. 1 is set in an anechoic chamber,
The noise generated under the above conditions is classified into ISO 7779 6.
Measured according to the section. As a result, the noise, which was nearly 55 dB in the conventional device shown in FIG. 4, was reduced to 33 dB.

【００３０】また、第２の導電部としての金属電極１ｄ
に印加するバイアスは交流バイアスに限らず、直流成分
を含んだ交流バイアスであってもよい。この場合、該電
極１ｄによる感光ドラム２の均し効果はより顕著に認め
られた。[0030] Also, a metal electrode 1d as a second conductive part
The bias applied to is not limited to an alternating current bias, but may be an alternating current bias containing a direct current component. In this case, the leveling effect of the photosensitive drum 2 by the electrode 1d was more noticeable.

【００３１】〈実施例２〉（図２）図２の実施例は、前
述図１の帯電装置について第１の導電部１ａの感光ドラ
ム回転方向下流側にも第２の導電部１ｅを配置したもの
である。この導電部１ｅにも上流側の導電部１ｄと同じ
バイアスが印加されており、帯電音が発生しないばかり
か、感光ドラム２に対する電位の均し効果も倍増すると
いう利点がある。Embodiment 2 (FIG. 2) In the embodiment shown in FIG. 2, a second conductive portion 1e is also disposed on the downstream side of the first conductive portion 1a in the rotational direction of the photosensitive drum in the charging device shown in FIG. It is something. The same bias as that of the upstream conductive part 1d is applied to this conductive part 1e, which has the advantage that not only no charging noise is generated, but also the effect of leveling the potential on the photosensitive drum 2 is doubled.

【００３２】〈実施例３〉（図３）図３の実施例は感光
ドラム２に接触させて直流電圧のみを印加する第１の導
電部を感光ドラム２の回転に従動回転するローラ体１に
し、該ローラ体１の感光ドラム回転方向の上流側と下流
側との両方に、交流電圧を印加する、感光ドラム２に非
接触の第２の導電部１ｄ・１ｅを配設した構成である。Embodiment 3 (FIG. 3) In the embodiment shown in FIG. 3, the first conductive part that contacts the photosensitive drum 2 and applies only a DC voltage is replaced by a roller body 1 that rotates following the rotation of the photosensitive drum 2. , the photosensitive drum 2 is provided with non-contact second conductive portions 1d and 1e, which apply an alternating current voltage to both the upstream and downstream sides of the roller body 1 in the photosensitive drum rotation direction.

【００３３】第１の導電部としてのローラ体１は本実施
例は前述図４の帯電ローラと同様の層構成をもつ複合層
構成のものであり、１１は直流バイアスを印加するため
の芯金電極、１２は直流電圧が印加される導電性ゴム等
の電極、１３は感光体表面の欠陥に対し火花放電を起こ
させないために高抵抗層である。In this embodiment, the roller body 1 serving as the first conductive portion has a composite layer structure similar to that of the charging roller shown in FIG. The electrode 12 is an electrode made of conductive rubber or the like to which a DC voltage is applied, and the numeral 13 is a high resistance layer to prevent spark discharge from occurring due to defects on the surface of the photoreceptor.

【００３４】而して第１の導電部としてのローラ体１は
、感光ドラム２と当接して従動回転するので、ローラ体
表面にトナー、紙粉等が付着しずらく、ローラ体表面に
汚れが発生しにくいという利点がある。Since the roller body 1 serving as the first conductive portion is driven to rotate while in contact with the photosensitive drum 2, it is difficult for toner, paper powder, etc. to adhere to the surface of the roller body, and dirt is prevented from forming on the surface of the roller body. It has the advantage of being less likely to occur.

【００３５】本実施例のように第１の導電部が従動ロー
ラである場合の被帯電体との相対移動は該ローラの軸と
被帯電体との相対移動運動のことである。When the first conductive portion is a driven roller as in this embodiment, the relative movement with respect to the object to be charged refers to the relative movement between the axis of the roller and the object to be charged.

【００３６】なお、被帯電体としての感光体の帯電極性
はマイナスに限定されることなくプラスであってもよい
ことはいうまでもない。[0036] It goes without saying that the charging polarity of the photoreceptor as the object to be charged is not limited to negative, but may be positive.

【００３７】[0037]

【発明の効果】上記のように、本発明によれば、帯電部
材に直流電圧と交流電圧を印加して被帯電体面を均一に
帯電する接触帯電方法において、交流電圧の印加による
帯電の均し効果は維持しつつ、帯電音の発生を防止する
ことが可能である。また帯電音を防止することができる
ようになった結果、印加交流電圧の周波数を大きな値に
設定することが可能になり、プロセススピードの高速化
に対応できる等の効果が得られる。As described above, according to the present invention, in a contact charging method in which the surface of a charged object is uniformly charged by applying a DC voltage and an AC voltage to a charging member, charging can be leveled by applying an AC voltage. It is possible to prevent the generation of charging noise while maintaining the effect. Furthermore, since charging noise can be prevented, the frequency of the applied alternating current voltage can be set to a large value, resulting in effects such as being able to cope with increased process speed.

【図面の簡単な説明】[Brief explanation of the drawing]

【図１】　　第１実施例の概略図[Figure 1] Schematic diagram of the first embodiment

【図２】　　第２実施例の要部図[Figure 2] Main part diagram of the second embodiment

【図３】　　第３実施例の要部図[Figure 3] Main part diagram of the third embodiment

【図４】　　従来例の概略図[Figure 4] Schematic diagram of conventional example

【図５】　　（Ａ）・（Ｂ）・（Ｃ）は夫々帯電音の発
生メカニズム説明図[Figure 5] (A), (B), and (C) are illustrations of the mechanism of generation of charging noise, respectively.

【符号の説明】[Explanation of symbols]

１ａ・１　　　　第１の導電部としての金属電極又はロ
ーラ体 １ｄ・１ｅ　　第２の導電部としての金属電極２　　　
　被帯電体としての感光ドラム３　　　　直流電源 ４　　　　交流電源1a/1 Metal electrode or roller body 1d/1e as the first conductive part Metal electrode 2 as the second conductive part
Photosensitive drum 3 as a charged object DC power supply 4 AC power supply

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】　　被帯電体に直接または抵抗層を介して
接触して被帯電体と相対移動する第１の導電部と、該第
１の導電部の前記被帯電体との相対移動方向の上流側ま
たは下流側或いは上流側と下流側とに該第１の導電部に
非導通に近接させて且つ被帯電体とは非接触に対向させ
て第２の導電部を具備させ、前記第１の導電部には直流
電圧のみを、前記第２の導電部には交流電圧又は交流電
圧と直流電圧の重畳電圧を印加して被帯電体面を接触帯
電することを特徴とする接触帯電方法。1. A first conductive part that moves relative to the charged body by contacting the charged body directly or through a resistance layer; and a first conductive part that moves relative to the charged body, and A second conductive part is provided on the upstream side or the downstream side, or on the upstream side and the downstream side, in a non-conducting manner close to the first conductive part and facing the charged body without contacting it, A contact charging method characterized in that the surface of the object to be charged is contact-charged by applying only a DC voltage to the conductive part and applying an AC voltage or a superimposed voltage of AC voltage and DC voltage to the second conductive part.