JPH07306568A

JPH07306568A - Electrifying device

Info

Publication number: JPH07306568A
Application number: JP9938394A
Authority: JP
Inventors: Masahiko Nakamura; 政彦中村; Hajime Yamamoto; 肇山本; Hiroshi Terada; 浩寺田
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1994-05-13
Filing date: 1994-05-13
Publication date: 1995-11-21

Abstract

PURPOSE:To provide an electrifying device whose constitution is simple and which realizes stable electrification. CONSTITUTION:This device is provided with a photoreceptor 1, and an electrifying electrode roller 2 set on the outer periphery of the photoreceptor 1 through a gap, including a positionally fixed magnet 3 and rotating and moving in a reverse direction to the photoreceptor 1. The fixed magnet 3 is installed inside the roller 2 and has the peak of magnetic flux density on the downstream side of the roller 2 with respect to the most closest part of the photoreceptor 1 to the electrode 2 and does not have the peak of the magnetic flux density on the upstream side thereof. By impressing voltage on the roller 2 while moving magnetic particles 5 forming particle bank 4 between the photoreceptor 1 and the roller 2 by magnetic force and the carrying force of the roller 2, the photoreceptor 1 is electrified in the electrifying device. Since the photoreceptor 1 is electrified by using the magnetic particles 5, the production quantity of ozone is small. The adhesion of the magnetic particles 5 to the photoreceptor 1 is prevented by the carrying force of the roller 2 and the magnetic force with simple constitution.

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、プリンタやファクシミ
リ等に応用できる帯電装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device applicable to printers, facsimiles and the like.

【０００２】[0002]

【従来の技術】従来から電子写真方法においては、感光
体を帯電させる方法が種々考案されている。たとえば代
表的なものとしては、コロナ帯電器がある。コロナ帯電
器は安定した帯電機能を有し広く実用化されているが、
多量のオゾンを発生するので、事務所内の環境保持の観
点から、近年はコロナ放電を用いない帯電器が開発され
つつある（電子写真学会誌，２７．４，５７３（１９８
８））。それらには弾性ローラを用いるもの（特開平１
−２６７６６７号公報）、導電性粒子を用いた接触帯電
法（Ｊ．Ａｐｐｌ．Ｐｈｙｓ．６２，２６６５（１９８
７））などがある。2. Description of the Related Art Conventionally, various electrophotographic methods have been devised for charging a photoreceptor. For example, a typical one is a corona charger. Although the corona charger has a stable charging function and is widely used,
Since a large amount of ozone is generated, a charger that does not use corona discharge is being developed in recent years from the viewpoint of maintaining the environment in the office (Electrophotographic Society, 27.4, 573 (198).
8)). Those that use elastic rollers
No. 267667), a contact charging method using conductive particles (J. Appl. Phys. 62, 2665 (198).
7)) etc.

【０００３】そのなかで導電性粒子を用いた接触帯電法
を、図１２を用いて少し詳しく説明する。図１２におい
て、１０１は導電性基体１０２の上に形成された感光体
である。１０３は前記感光体１０１の面に対向するよう
に設けられ、矢印の方向、つまり感光体１０１の移動方
向と同方向に回転移動する帯電電極ローラである。この
担持帯電電極ローラ１０３内には固定磁石１０４が固定
されその外周には導電性の磁性粒子１０５を担持させて
いる。そして帯電電極ローラ１０３には、高圧電源１０
６より高圧を印加するようにしている。Among them, the contact charging method using conductive particles will be described in some detail with reference to FIG. In FIG. 12, 101 is a photoconductor formed on the conductive substrate 102. A charging electrode roller 103 is provided so as to face the surface of the photoconductor 101 and rotates in the direction of the arrow, that is, in the same direction as the moving direction of the photoconductor 101. A fixed magnet 104 is fixed inside the carrying charging electrode roller 103, and conductive magnetic particles 105 are carried on the outer periphery thereof. The charging electrode roller 103 is connected to the high voltage power source 10
A higher voltage than 6 is applied.

【０００４】以上のように構成された帯電装置につい
て、その動作について説明する。帯電電極ローラ１０３
を回転させると磁性粒子１０５は矢印の方向に移動す
る。高圧電源１０６で帯電電極ローラ１０３に電圧を印
加すると、磁性粒子１０５と感光体１０１の微少な空間
で放電を起こし、感光体１０１は帯電される。The operation of the charging device configured as described above will be described. Charging electrode roller 103
When is rotated, the magnetic particles 105 move in the direction of the arrow. When a voltage is applied to the charging electrode roller 103 by the high voltage power supply 106, electric discharge is caused in the minute space between the magnetic particles 105 and the photoconductor 101, and the photoconductor 101 is charged.

【０００５】[0005]

【発明が解決しようとする課題】しかしながら上記のよ
うな構成では、磁性粒子１０５が感光体１０１側に付着
し持ち去られてしまう、いわゆるキャリア付着現象が発
生し、後の露光や現像工程に悪影響を与えていた。ま
た、帯電電極ローラ１０３はローラ全周に磁性粒子１０
５を担持するため、磁性粒子１０５は重力および遠心力
などの影響で帯電電極ローラ１０３からこぼれ落ち、装
置内を汚すとともに帯電電位にも悪影響を与えていた。
この現象は特に帯電電極ローラ１０３を速く回転させた
ときや、装置が大きく振動したときに顕著に発生した。However, in the above structure, a so-called carrier adhesion phenomenon occurs in which the magnetic particles 105 adhere to the photoreceptor 101 side and are carried away, which adversely affects the subsequent exposure and development processes. I was giving. Further, the charging electrode roller 103 has magnetic particles 10 around the entire circumference of the roller.
In order to carry No. 5, the magnetic particles 105 spilled from the charging electrode roller 103 under the influence of gravity, centrifugal force, etc., thereby polluting the inside of the apparatus and adversely affecting the charging potential.
This phenomenon remarkably occurred especially when the charging electrode roller 103 was rotated rapidly or when the apparatus vibrated significantly.

【０００６】本発明は上記問題点に鑑み、構成が簡単で
しかも安定した帯電を与えることのできる帯電装置を提
供することを目的とするものである。In view of the above problems, it is an object of the present invention to provide a charging device having a simple structure and capable of providing stable charging.

【０００７】[0007]

【課題を解決するための手段】上記問題点を解決するた
めに本発明は、少なくとも移動する電子写真用の感光体
の表面と所定の間隙を有した位置に設置され、進行方向
が前記感光体の進行方向と逆方向に回転する帯電電極ロ
ーラと、前記感光体と前記帯電電極ローラの隙間で粒子
溜まりを形成しながら移動する導電性の磁性粒子と、前
記帯電電極ローラ内部に固定された固定磁石と、前記帯
電電極ローラに電圧を印加する手段と、を有する帯電装
置であって、前記固定磁石が前記感光体と前記帯電電極
ローラの最近接部に対し前記最近接部を含む前記帯電電
極ローラ回転方向の下流側に磁束密度のピークを有し、
かつ上流側に磁束密度のピークを持たない帯電装置の構
成とする。In order to solve the above-mentioned problems, the present invention is installed at a position having a predetermined gap with at least the surface of a moving electrophotographic photosensitive member, and the advancing direction is the photosensitive member. Charging roller that rotates in the direction opposite to the moving direction, conductive magnetic particles that move while forming a particle pool in the gap between the photoconductor and the charging electrode roller, and a fixed member that is fixed inside the charging electrode roller. A charging device comprising a magnet and means for applying a voltage to the charging electrode roller, wherein the fixed magnet includes the closest portion to the closest portion of the photoconductor and the charging electrode roller. Has a peak of magnetic flux density on the downstream side in the roller rotation direction,
In addition, the charging device is configured so that there is no peak of magnetic flux density on the upstream side.

【０００８】さらに本発明は、少なくとも移動する電子
写真用の感光体の表面と所定の間隙を有した位置に設置
され、進行方向が前記感光体の進行方向と逆方向に回転
する帯電電極ローラと、前記感光体と前記帯電電極ロー
ラの隙間で粒子溜まりを形成しながら移動する導電性の
磁性粒子と、前記帯電電極ローラ内部に固定された固定
磁石と、前記帯電電極ローラに電圧を印加する手段を備
え、前記帯電電極ローラの回転にともなって移動する前
記磁性粒子を前記帯電電極ローラ上から除去するスクレ
ーパを設けたを帯電装置の構成とする。Further, according to the present invention, there is provided a charging electrode roller which is installed at a position having a predetermined gap from at least the surface of a moving electrophotographic photosensitive member and which rotates in a traveling direction opposite to the traveling direction of the photosensitive member. , Conductive magnetic particles that move while forming a particle pool in the gap between the photoconductor and the charging electrode roller, a fixed magnet fixed inside the charging electrode roller, and means for applying a voltage to the charging electrode roller And a scraper for removing from the charging electrode roller the magnetic particles that move with the rotation of the charging electrode roller.

【０００９】また本発明は前記固定磁石の前記帯電電極
ローラ表面における磁束密度のピークが１つであるこ
と、あるいは前記固定磁石が前記帯電電極ローラ表面に
おいて少なくとも隣合う２つの互いに異なる極性の磁束
密度のピークを持つ構成とする。また本発明は前記帯電
電極ローラの周速が前記感光体の周速より速くする構成
とする。また本発明は前記電圧印加手段による電圧の印
加を前記感光体の移動中のみ行うこと、あるいは前記電
圧印加手段による電圧の印加が所定の電圧値に制御され
た直流定電圧であること、あるいは前記電圧印加手段に
よる電圧の印加が所定の電流値に制御された直流定電流
であること、あるいは前記電圧印加手段による電圧の印
加が交流成分を有するようにする。According to the present invention, the magnetic flux density of the fixed magnet on the surface of the charging electrode roller is one, or the fixed magnet has at least two magnetic flux densities of different polarities adjacent to each other on the surface of the charging electrode roller. It has a peak of. Further, in the present invention, the peripheral speed of the charging electrode roller is set to be higher than the peripheral speed of the photoconductor. Further, the present invention applies the voltage by the voltage applying means only while the photosensitive member is moving, or applies the voltage by the voltage applying means with a constant DC voltage controlled to a predetermined voltage value, or The voltage applied by the voltage applying means is a direct current constant controlled to a predetermined current value, or the voltage applied by the voltage applying means has an AC component.

【００１０】本発明は、さらに前記スクレーパが前記感
光体と前記帯電電極ローラの最近接部から前記帯電電極
ローラ回転方向に対する下流側に９０゜以内の位置で前
記帯電電極ローラと接触する構成とする。According to the present invention, the scraper further comes into contact with the charging electrode roller at a position within 90 ° from the closest portion of the photosensitive member and the charging electrode roller to the downstream side in the rotation direction of the charging electrode roller. .

【００１１】[0011]

【作用】図１２で示した従来例の構成では、帯電電極ロ
ーラ１０３内の固定磁石１０４は、帯電電極ローラ１０
３の表面において感光体１０１と帯電電極ローラ１０３
の最近接部より感光体移動方向下流側に磁束密度のピー
クを有する。この下流側の磁束密度のピークによる磁力
は、感光体１０１と帯電電極ローラ１０３の最近接部付
近の磁性粒子１０５を感光体移動方向下流側に引く力と
して磁性粒子１０５に作用するため、磁性粒子１０５は
感光体１０１の移動とともに感光体に持ち去られる。こ
のような磁力は図１２で示したような固定磁石１０４の
場合だけでなく、固定磁石を回転移動させた場合でも磁
力の方向と大きさは変化するが同様に発生する。In the configuration of the conventional example shown in FIG. 12, the fixed magnet 104 in the charging electrode roller 103 is the charging electrode roller 10
On the surface of No. 3, the photoconductor 101 and the charging electrode roller 103
Has a peak of the magnetic flux density on the downstream side in the moving direction of the photoconductor from the closest portion of. The magnetic force due to the peak of the magnetic flux density on the downstream side acts on the magnetic particles 105 as a force pulling the magnetic particles 105 near the closest portion of the photoconductor 101 and the charging electrode roller 103 to the downstream side in the moving direction of the photoconductor. 105 is carried away by the photoconductor as the photoconductor 101 moves. Such magnetic force is generated not only in the case of the fixed magnet 104 as shown in FIG. 12, but also in the case where the fixed magnet is rotationally moved, although the direction and magnitude of the magnetic force change, but similarly.

【００１２】本発明の構成では、固定磁石は帯電電極ロ
ーラ表面において感光体と帯電電極ローラの最近接部よ
り感光体移動方向下流側に磁束密度のピークを持たない
ため、磁性粒子がこの磁力の影響で感光体に持ち運ばれ
ることを防ぐことができる。In the structure of the present invention, since the fixed magnet does not have a peak of magnetic flux density on the surface of the charging electrode roller on the downstream side in the moving direction of the photosensitive member from the closest portion of the photosensitive member and the charging electrode roller, the magnetic particles have this magnetic force. It can be prevented from being carried to the photoconductor due to the influence.

【００１３】また、固定磁石の磁極が１極の場合には、
磁束密度のピークを感光体と帯電電極ローラの最近接部
より感光体移動方向下流側にずらすと、前記の従来例と
同様に磁性粒子が感光体に持ち去られるとともに帯電電
位のバラツキが大きくなることがわかった。特にずらす
角度を５゜以上にするとこの傾向は顕著になる。逆に磁
束密度のピークを最近接部より感光体移動方向上流側に
ずらすと、従来例のように磁性粒子が感光体に持ち去ら
れることはない。しかし、この角度を大きくしすぎると
帯電電極ローラ上の磁性粒子の穂立ちの位置が最近接部
より上流側にずれすぎるため、最近接部に磁束密度のピ
ークがあるときより感光体と磁性粒子の接触効率が悪く
なる。その結果、帯電電極ローラの印加電圧に対する帯
電電位が低くなってしまう。特にずらす角度を５゜以上
にするとこの傾向は顕著になる。When the fixed magnet has only one magnetic pole,
If the peak of the magnetic flux density is shifted to the downstream side of the moving direction of the photoconductor from the closest portion of the photoconductor and the charging electrode roller, the magnetic particles are carried away to the photoconductor and the variation of the charging potential becomes large as in the conventional example. I understood. This tendency becomes remarkable especially when the shift angle is 5 ° or more. On the contrary, if the peak of the magnetic flux density is shifted to the upstream side in the moving direction of the photoconductor from the closest portion, magnetic particles will not be carried away by the photoconductor as in the conventional example. However, if this angle is made too large, the position of the spikes of the magnetic particles on the charging electrode roller will shift too far upstream from the closest portion, so that when the peak of the magnetic flux density is present at the closest portion, the photoconductor and the magnetic particles will not move. Contact efficiency will deteriorate. As a result, the charging potential with respect to the applied voltage of the charging electrode roller becomes low. This tendency becomes remarkable especially when the shift angle is 5 ° or more.

【００１４】本発明の構成では、感光体と帯電電極ロー
ラの最近接部に磁束密度のピークを持たせることによ
り、前記最近接部での磁性粒子の穂立ちが安定するた
め、磁性粒子と感光体の接触が安定する。その結果、帯
電電位のバラツキを小さくできる。さらに、前記最近接
部の磁束密度のピークによる磁力は、従来例とは逆に磁
性粒子に対して最近接部方向に戻す力となって作用する
ため、感光体の移動にともなって感光体に持ち去られよ
うとしている磁性粒子を最近接部方向に引き戻すことが
できる。In the structure of the present invention, the peak of the magnetic flux density is provided at the closest portion of the photoconductor and the charging electrode roller, so that the spikes of the magnetic particles at the closest portion are stabilized, so that the magnetic particles and the photosensitive electrode roller are exposed. Body contact is stable. As a result, variations in charging potential can be reduced. Further, the magnetic force due to the peak of the magnetic flux density at the closest portion acts as a force to return to the magnetic particles in the direction of the closest portion, contrary to the conventional example, so that the photoreceptor moves as the photoreceptor moves. The magnetic particles that are about to be carried away can be pulled back toward the closest point.

【００１５】さらに、帯電電極ローラを感光体の移動方
向とは逆の方向に移動させると、感光体の移動にともな
って感光体に持ち去られようとしている磁性粒子を最近
接部方向に機械的に搬送する力も加わるため、前記の感
光体が磁性粒子を持ち去ることを防ぐ力はより一層強く
なる。Further, when the charging electrode roller is moved in the direction opposite to the moving direction of the photoconductor, the magnetic particles which are about to be carried away by the photoconductor along with the movement of the photoconductor are mechanically moved toward the closest point. Since the conveying force is also added, the force for preventing the photoconductor from taking away the magnetic particles becomes stronger.

【００１６】図４に帯電電極ローラを感光体の移動方向
と逆の方向に移動させた場合の帯電電極ローラと感光体
の周速比（帯電電極ローラ：感光体）と帯電電位のバラ
ツキの関係を示す。図４から帯電電位のバラツキは、帯
電電極ローラと感光体の周速比を１：１よりも大きくす
ることにより極めて小さくできることがわかる。このよ
うに帯電電極ローラを感光体の移動方向と逆の方向に回
転移動させ、かつその周速比を大きくすることにより、
感光体と帯電電極ローラの最近接部付近の磁性粒子の運
動が活発になり感光体の帯電電位のバラツキを低減でき
る。FIG. 4 shows the relationship between the peripheral speed ratio (charging electrode roller: photosensitive member) of the charging electrode roller and the photosensitive member when the charging electrode roller is moved in the direction opposite to the moving direction of the photosensitive member and the variation of the charging potential. Indicates. It can be seen from FIG. 4 that the variation in the charging potential can be made extremely small by setting the peripheral speed ratio between the charging electrode roller and the photosensitive member to be larger than 1: 1. In this way, by rotating the charging electrode roller in the direction opposite to the moving direction of the photoconductor and increasing the peripheral speed ratio,
The movement of the magnetic particles in the vicinity of the closest portion between the photoconductor and the charging electrode roller becomes active, and the variation in the charging potential of the photoconductor can be reduced.

【００１７】さらに本発明の構成のように、固定磁石の
帯電電極ローラ表面における磁束密度のピークを２つの
互いに異なる極性のピークにすると、感光体と帯電電極
ローラの最近接部付近の磁性粒子に感光体の移動とは反
対の向きに磁力を作用させることができる。こうする
と、最近接部付近の磁性粒子の循環が活発になり帯電電
位はより一層均一にかつ安定化する。Further, when the peak of the magnetic flux density on the surface of the charging electrode roller of the fixed magnet is set to two peaks of polarities different from each other as in the constitution of the present invention, magnetic particles near the closest portion of the photosensitive member and the charging electrode roller are formed. The magnetic force can be applied in the direction opposite to the movement of the photoconductor. By doing so, the circulation of the magnetic particles in the vicinity of the closest portion becomes active, and the charging potential becomes more uniform and stable.

【００１８】さらに本発明では、帯電電極ローラ上の磁
性粒子を一旦除去するスクレーパを設けることにより、
より安定した帯電が得られる。こうすると、帯電電極ロ
ーラ上での帯電に関与しない表面には、帯電電極ローラ
は磁性粒子を担持しないので、装置に振動が加わったと
きなどに磁性粒子の帯電電極ローラへの付着状態が変わ
ったり、こぼれ落ちたりすることを防止できる。さら
に、磁性粒子の必要量を少なくでき装置を小型化できる
効果もある。また、感光体と帯電電極ローラの最近接部
から帯電電極ローラの回転移動方向下流側の９０゜以内
の位置でスクレーパを帯電電極ローラに接触させると、
図５の矢印Ａで示すように、磁性粒子Ｂの循環を小さく
できる。その結果、スクレーパで帯電電極ローラから除
去された磁性粒子を容易に最近接部方向に戻すことがで
きる。こうすると、磁性粒子の循環はスムーズに行われ
るので、磁性粒子の量が少ない場合でも感光体の帯電電
位を安定させることができる。Further, in the present invention, by providing a scraper for temporarily removing the magnetic particles on the charging electrode roller,
More stable charging can be obtained. By doing this, since the charging electrode roller does not carry magnetic particles on the surface of the charging electrode roller that is not involved in charging, the adhesion state of the magnetic particles to the charging electrode roller may change when the device is vibrated. It can prevent spillage. Further, there is an effect that the required amount of magnetic particles can be reduced and the device can be downsized. When the scraper is brought into contact with the charging electrode roller at a position within 90 ° on the downstream side in the rotational movement direction of the charging electrode roller from the closest portion of the photosensitive member and the charging electrode roller,
As shown by the arrow A in FIG. 5, the circulation of the magnetic particles B can be reduced. As a result, the magnetic particles removed from the charging electrode roller by the scraper can be easily returned to the closest contact direction. By doing so, the circulation of the magnetic particles is performed smoothly, so that the charging potential of the photoconductor can be stabilized even when the amount of the magnetic particles is small.

【００１９】図６および図７に本発明で帯電電極ローラ
に直流電圧を印加した場合と交流電圧を印加した場合の
帯電電位の比較を示す。図６は印加する交流電圧の周波
数を変えた場合の帯電電位の変化を、図７は印加する交
流電圧の振幅を変えた場合の帯電電位の変化を示す。こ
のように、帯電電極ローラへの印加電圧を交流電圧にす
ることにより直流電圧を印加した場合より帯電開始電圧
を低くできる。FIGS. 6 and 7 show a comparison of charging potentials when a DC voltage is applied to the charging electrode roller and when an AC voltage is applied in the present invention. FIG. 6 shows changes in the charging potential when the frequency of the applied AC voltage is changed, and FIG. 7 shows changes in the charging potential when the amplitude of the applied AC voltage is changed. In this way, by changing the voltage applied to the charging electrode roller to an AC voltage, the charging start voltage can be made lower than when a DC voltage is applied.

【００２０】また、感光体と帯電電極ローラが停止して
いるときに帯電電極ローラに電圧を印加すると、感光体
に傷がある場合その傷の部分で連続的にリークが発生
し、傷周辺の感光層を著しく損傷することがある。本発
明では、電圧印加を感光体移動時に行う構成である。こ
れにより、電圧印加時には常に磁性粒子が活発に動いて
いるので、前記のように感光体に傷がある場合でも連続
的なリークによる過大な感光層の損傷は発生しない。Further, when a voltage is applied to the charging electrode roller while the photosensitive member and the charging electrode roller are stopped, if the photosensitive member has a scratch, a leak is continuously generated at the scratched portion, and the leakage around the scratch occurs. It may seriously damage the photosensitive layer. In the present invention, the voltage is applied when the photoconductor is moved. As a result, since the magnetic particles are actively moving when a voltage is applied, even if the photoconductor is scratched as described above, excessive damage to the photosensitive layer due to continuous leakage does not occur.

【００２１】[0021]

【実施例】本発明に使用する感光体には、酸化亜鉛、セ
レン、硫化カドミウム、アモルファスシリコン、さらに
フタロシアニンやアゾ顔料による有機感光体等を用いる
ことができる。EXAMPLES As the photoreceptor used in the present invention, an organic photoreceptor containing zinc oxide, selenium, cadmium sulfide, amorphous silicon, phthalocyanine or an azo pigment can be used.

【００２２】本発明に用いる磁性粒子は、鉄粉、マグネ
タイトやフェライトなどの粉、ニッケル粒子などを用い
ることができる。それらをそのまま用いてもよいし、さ
らには表面を酸化鉄で覆ったもの、高抵抗のたとえばテ
フロンやシリコン樹脂の薄膜で覆ったものでもよい。ま
た導電性粒子の中に少量の絶縁性粒子を混合したもので
もよい。粒子の抵抗値は印加する電圧にもよるが、１０
³〜１０⁸Ωｃｍ程度の抵抗値が好ましい。またその粒径
は１０μｍから２００μｍが適当で、さらに好ましくは
２０μｍから１００μｍである。As the magnetic particles used in the present invention, iron powder, powder of magnetite or ferrite, nickel particles and the like can be used. They may be used as they are, or may be those whose surface is covered with iron oxide or whose surface is covered with a thin film of high resistance such as Teflon or silicon resin. Also, a small amount of insulating particles may be mixed in the conductive particles. The resistance value of the particles depends on the applied voltage, but is 10
A resistance value of about ³ to 10 ⁸ Ωcm is preferable. The particle size is suitably 10 μm to 200 μm, more preferably 20 μm to 100 μm.

【００２３】本発明に使用する帯電電極ローラと感光体
の距離は磁性粒子の粒径や抵抗値にもよるが、２００μ
ｍ〜１．５ｍｍ程度が好ましい。また、帯電電極ローラ
表面は磁性粒子の搬送を促進するためにサンドブラスト
等で粗面化してもよい。The distance between the charging electrode roller and the photosensitive member used in the present invention depends on the particle diameter of the magnetic particles and the resistance value, but is 200 μm.
It is preferably about m to 1.5 mm. Further, the surface of the charging electrode roller may be roughened by sandblasting or the like in order to accelerate the transportation of the magnetic particles.

【００２４】帯電電極ローラに印加する電圧としては直
流電圧でも直流電圧を重畳した交流電圧でも良い。直流
電圧を印加する場合、磁性粒子の抵抗値や感光体と帯電
電極ローラとの距離にもよるが、−５００Ｖ以下（絶対
値で５００Ｖより大きい電圧）を印加することが好まし
い。また、交流電圧を印加する場合は１００Ｈｚ〜２ｋ
Ｈｚ、振幅はピーク・ツー・ピークで１ｋＶ以上を印加
することが好ましい。The voltage applied to the charging electrode roller may be a DC voltage or an AC voltage on which a DC voltage is superimposed. When applying a DC voltage, it is preferable to apply −500 V or less (absolute voltage greater than 500 V), although it depends on the resistance value of the magnetic particles and the distance between the photoconductor and the charging electrode roller. When applying an AC voltage, 100 Hz to 2 k
It is preferable to apply a peak-to-peak frequency of 1 kV or more in Hz and amplitude.

【００２５】以下本発明の帯電装置について、図面を参
照しながら説明する。（実施例１）図１は本発明の帯電装置の一実施例を示す
ものである。図１において、１はフタロシアニンをポリ
エステル系バインダ樹脂に分散した有機のドラム状の感
光体（外径３０ｍｍ）、２は前記感光体１の外周面に対
し間隙をもたせて設置されたステンレス製の帯電帯電電
極ローラ（外径１６ｍｍ、内径１５ｍｍ）である。前記
帯電電極ローラ２には同軸に固定された固定磁石３（外
周半径７ｍｍ）を設けてあり、帯電電極ローラ２の発光
体１に対向する部分には、表面をシリコンコートした粒
径３０μｍの磁性粒子５が形成する粒子溜まり４が形成
されている。６は帯電電極ローラ２に電圧を印加する交
流高圧電源である。前記帯電電極ローラ２の外周部には
磁性粒子５を内包するホッパ７と、磁性粒子５がホッパ
７からのこぼれを防ぐ薄いポリエステルフィルム製のシ
ール材８を設けてあり、シール材８は、その一方の先端
が感光体１表面に接触するようにホッパ７の先端部分に
取り付けられている。なお帯電電極ローラ２と感光体１
との距離は３５０μｍに設定し、感光体１は、周速６０
ｍｍ／ｓで図１の矢印方向に回転させるようにした。ま
た、帯電電極ローラ２は周速１２０ｍｍ／ｓで、感光体
１の進行方向とは逆方向（図１の矢印方向）に回転させ
るようにした。The charging device of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 shows an embodiment of a charging device of the present invention. In FIG. 1, reference numeral 1 is an organic drum-shaped photosensitive member (outer diameter: 30 mm) in which phthalocyanine is dispersed in a polyester binder resin, and 2 is a stainless steel charging device provided with a gap from the outer peripheral surface of the photosensitive member 1. It is a charging electrode roller (outer diameter 16 mm, inner diameter 15 mm). The charging electrode roller 2 is provided with a fixed magnet 3 coaxially fixed (outer radius 7 mm), and the surface of the charging electrode roller 2 facing the light emitting body 1 is coated with silicon and has a magnetism of a particle size of 30 μm. A particle pool 4 formed by particles 5 is formed. Reference numeral 6 is an AC high-voltage power supply that applies a voltage to the charging electrode roller 2. A hopper 7 containing the magnetic particles 5 and a sealing material 8 made of a thin polyester film for preventing the magnetic particles 5 from spilling from the hopper 7 are provided on the outer peripheral portion of the charging electrode roller 2. It is attached to the tip portion of the hopper 7 so that one tip is in contact with the surface of the photoconductor 1. The charging electrode roller 2 and the photoconductor 1
Is set to 350 μm, and the photoconductor 1 has a peripheral speed of 60 μm.
It was made to rotate in the arrow direction of FIG. 1 at mm / s. Further, the charging electrode roller 2 was rotated at a peripheral speed of 120 mm / s in the direction opposite to the traveling direction of the photoconductor 1 (the direction of the arrow in FIG. 1).

【００２６】図８に固定磁石３による帯電電極ローラ２
表面の垂直方向の磁束密度の分布を示す。図８では磁束
密度がピーク値を示す部分を０゜として、帯電電極ロー
ラ２の回転移動方向の上流側を−側、下流側を＋側とし
て示している。磁石３による帯電電極ローラ２表面での
ピーク磁束密度は６００Ｇs（Ｎ極）であった。本実施
例では前記した固定磁石３の帯電電極ローラ２表面での
磁束密度のピーク位置が感光体１と帯電電極ローラ２の
最近接位置になるように固定磁石３を固定した。FIG. 8 shows a charging electrode roller 2 using a fixed magnet 3.
The distribution of magnetic flux density in the vertical direction of the surface is shown. In FIG. 8, the portion where the magnetic flux density shows a peak value is 0 °, the upstream side in the rotational movement direction of the charging electrode roller 2 is the − side, and the downstream side is the + side. The peak magnetic flux density on the surface of the charging electrode roller 2 by the magnet 3 was 600 Gs (N pole). In this embodiment, the fixed magnet 3 is fixed so that the peak position of the magnetic flux density of the fixed magnet 3 on the surface of the charging electrode roller 2 is the closest position between the photoconductor 1 and the charging electrode roller 2.

【００２７】また、図１において９は感光体１に投射さ
れる信号光、１０は感光体１外周でかつ、帯電電極ロー
ラ２より下流側に設けた現像剤溜め、１１はその現像剤
溜め１０に充填された絶縁性磁性１成分現像剤、１２は
感光体１と３００μｍのギャップを開けて設定し、カラ
ー部が絶縁性磁性１成分現像剤１１に接する現像電極ロ
ーラ、１３は現像電極ローラ１２の内部に設置された磁
石である。１４は感光体１内部に固定された磁石、１５
は現像電極ローラ１２に電圧を印加する交流高圧電源、
１６は現像電極ローラ上の現像剤をかきおとすポリエス
テルフィルム製のスクレーパ、１７は感光体上のトナー
像を紙に転写する転写ローラである。なお現像電極ロー
ラ１２は周速６０ｍｍ／ｓで感光体１の進行方向とは逆
方向（図１の矢印方向）に回転させるようにした。また
磁性１成分現像剤１１には粒径５μｍの微粒子絶縁性磁
性１成分トナーを用いた。磁性１成分トナーの構成は、
ポリエステル樹脂７０％、フェライト２５％、カーボン
ブラック３％、オキシカルボン酸金属錯体２％からな
り、さらにコロイダルシリカを１％外添して用いた（い
ずれも重量％）。Further, in FIG. 1, 9 is signal light projected on the photoconductor 1, 10 is a developer reservoir provided on the outer periphery of the photoconductor 1 and on the downstream side of the charging electrode roller 2, and 11 is the developer reservoir 10. Insulating magnetic one-component developer filled in 1 is set with a gap of 300 μm from the photoconductor 1, and a developing electrode roller in which the color portion is in contact with the insulating magnetic one-component developer 11 is a developing electrode roller 12 It is a magnet installed inside. 14 is a magnet fixed inside the photoconductor 1;
Is an AC high voltage power source for applying a voltage to the developing electrode roller 12,
Reference numeral 16 is a scraper made of a polyester film for scraping off the developer on the developing electrode roller, and 17 is a transfer roller for transferring the toner image on the photoconductor to paper. The developing electrode roller 12 was rotated at a peripheral speed of 60 mm / s in the direction opposite to the traveling direction of the photoconductor 1 (direction of arrow in FIG. 1). As the magnetic one-component developer 11, a fine particle insulating magnetic one-component toner having a particle diameter of 5 μm was used. The structure of the magnetic one-component toner is
A polyester resin 70%, ferrite 25%, carbon black 3%, and oxycarboxylic acid metal complex 2% were used, and 1% of colloidal silica was externally added and used (all are weight%).

【００２８】上記構成において、画像出力開始とともに
感光体１が回転を開始してから高圧電源６により帯電電
極ローラ２に、周波数１ｋＨｚ、電圧１ｋＶ（ピーク・
ツー・ピーク）、重畳直流電圧−６００Ｖの電圧を印加
したところ、感光体１は−５００Ｖに帯電した。このと
き、感光体１の表面電位のバラツキは±２０Ｖ程度であ
り、安定した均一な帯電が得られた。この感光体１に信
号光９を照射し静電潜像を形成した。このとき感光体１
の露光電位は−９０Ｖであった。この感光体１表面上
に、現像剤１１を現像剤溜め１０内で磁力により付着さ
せた。次に高圧電源１５により周波数１．８ｋＨｚ、電
圧１．５ｋＶ（ピーク・ツー・ピーク）、重畳直流電圧
−３００Ｖの電圧を印加し感光体１と逆方向に回転して
いる現像電極ローラ１２の前に感光体１を通過させた。
すると感光体１の帯電部分に付着したトナーは現像電極
ローラ１２に回収され、感光体１上には画像部にのみネ
ガポジ反転したトナー像が残った。こうして感光体１上
に得られたトナー像を、紙（図示せず）に、転写ローラ
１７によって転写した後、定着器（図示せず）により熱
定着した。このとき、帯電電極ローラ２近傍からのオゾ
ン発生はほとんど観察されなかった。また、帯電電極ロ
ーラ２から磁性粒子が感光体１に付着する現象も発生し
なかった。（実施例２）図２の構成は図１の構成と、帯電電極ロー
ラ２０表面に接触して帯電電極ローラ２０上の磁性粒子
２３を取り除くスクレーパ１８を付加した点が異なる。
以下、図２に示した帯電装置について説明する。In the above structure, after the photoconductor 1 starts to rotate at the same time as the image output starts, the charging electrode roller 2 is supplied to the charging electrode roller 2 by the high voltage power source 6 at a frequency of 1 kHz and a voltage of 1 kV (peak
Two-peak), and a voltage of -600V superimposed DC voltage was applied, and the photoreceptor 1 was charged to -500V. At this time, the variation in the surface potential of the photoconductor 1 was about ± 20 V, and stable and uniform charging was obtained. The photoconductor 1 was irradiated with signal light 9 to form an electrostatic latent image. At this time, the photoconductor 1
Had an exposure potential of -90V. The developer 11 was magnetically adhered to the surface of the photoreceptor 1 in the developer reservoir 10. Next, a voltage of 1.8 kHz, a voltage of 1.5 kV (peak-to-peak), and a superimposed DC voltage of -300 V are applied by the high-voltage power supply 15 in front of the developing electrode roller 12 rotating in the opposite direction to the photoconductor 1. Then, the photoconductor 1 was passed through.
Then, the toner attached to the charged portion of the photoconductor 1 was collected by the developing electrode roller 12, and the negative-positive inverted toner image remained only on the image portion on the photoconductor 1. The toner image thus obtained on the photosensitive member 1 was transferred onto paper (not shown) by the transfer roller 17, and then heat-fixed by a fixing device (not shown). At this time, almost no ozone generation was observed from the vicinity of the charging electrode roller 2. Further, the phenomenon that magnetic particles adhered to the photoconductor 1 from the charging electrode roller 2 did not occur. (Embodiment 2) The configuration of FIG. 2 differs from the configuration of FIG. 1 in that a scraper 18 for contacting the surface of the charging electrode roller 20 and removing the magnetic particles 23 on the charging electrode roller 20 is added.
The charging device shown in FIG. 2 will be described below.

【００２９】図２において、１９はフタロシアニンをポ
リエステル系バインダ樹脂に分散した有機のドラム状の
感光体（外径３０ｍｍ）、２０はステンレス製の帯電電
極ローラ（外径１６ｍｍ、内径１５ｍｍ）、２１は帯電
電極ローラ２０と同軸で固定された固定磁石（外周半径
７ｍｍ）、２２は表面をシリコンコートした粒径３０μ
ｍの磁性粒子２３が形成する粒子溜まり、２４は帯電電
極ローラ２０に電圧を印加する交流高圧電源である。２
５は磁性粒子２３を内包するホッパ、２６は磁性粒子２
３がホッパ２５からのこぼれを防ぐ薄いポリエステルフ
ィルム製のシール材で、一方の先端が感光体１９表面に
接触するようにホッパ２５の先端部分に取り付けられて
いる。帯電電極ローラ２０と感光体１９との距離は３５
０μｍに設定した。感光体１９は、周速６０ｍｍ／ｓで
図２の矢印方向に回転させるようにした。帯電電極ロー
ラ２０は周速１２０ｍｍ／ｓで感光体の進行方向とは逆
方向（図２の矢印方向）に回転させるようにした。In FIG. 2, 19 is an organic drum-shaped photosensitive member (outer diameter 30 mm) in which phthalocyanine is dispersed in polyester binder resin, 20 is a charging electrode roller (outer diameter 16 mm, inner diameter 15 mm) made of stainless steel, and 21 is A fixed magnet (outer radius 7 mm) fixed coaxially with the charging electrode roller 20, 22 is a silicon-coated particle size 30 μ
A particle pool formed by m magnetic particles 23, and 24 is an AC high-voltage power supply for applying a voltage to the charging electrode roller 20. Two
5 is a hopper containing magnetic particles 23, and 26 is magnetic particles 2
3 is a sealing material made of a thin polyester film for preventing spillage from the hopper 25, and is attached to the tip portion of the hopper 25 so that one end thereof contacts the surface of the photoconductor 19. The distance between the charging electrode roller 20 and the photoconductor 19 is 35
It was set to 0 μm. The photoconductor 19 was rotated in the direction of the arrow in FIG. 2 at a peripheral speed of 60 mm / s. The charging electrode roller 20 was rotated at a peripheral speed of 120 mm / s in the direction opposite to the traveling direction of the photoconductor (the direction of the arrow in FIG. 2).

【００３０】図９に固定磁石２１による帯電電極ローラ
２０表面の垂直方向の磁束密度の分布を示す。図９では
磁束密度がピーク値を示す部分を０゜として、帯電電極
ローラ２０の回転移動方向の上流側を−側、下流側を＋
側として示している。磁石２１による帯電電極ローラ２
０表面でのピーク磁束密度は６００Ｇs（Ｎ極）であっ
た。本実施例では前記した固定磁石２１の帯電電極ロー
ラ２０表面での磁束密度のピーク位置が感光体１９と帯
電電極ローラ２０の最近接位置になるように固定磁石２
１を固定した。FIG. 9 shows the distribution of the magnetic flux density in the vertical direction on the surface of the charging electrode roller 20 by the fixed magnet 21. In FIG. 9, the portion where the magnetic flux density shows a peak value is set to 0 °, the upstream side in the rotational movement direction of the charging electrode roller 20 is −, and the downstream side is +.
Shown as the side. Charging electrode roller 2 with magnet 21
The peak magnetic flux density on the 0 surface was 600 Gs (N pole). In this embodiment, the fixed magnet 2 is set so that the peak position of the magnetic flux density of the fixed magnet 21 on the surface of the charging electrode roller 20 is the closest position between the photoconductor 19 and the charging electrode roller 20.
Fixed 1

【００３１】１８は本実施例の特徴とする部材で、すな
わち帯電電極ローラ２０上の磁性粒子２３を帯電電極ロ
ーラ２０上から取り除くために設けられたポリエステル
フィルム製のスクレーパ（厚さ１５０μｍ、先端部自由
長３ｍｍ）であり、図２に示すように帯電電極ローラ２
０表面で感光体１９と帯電電極ローラ２０の最近接位置
から帯電電極ローラ２０の移動方向下流側に４５゜回転
した位置に接線方向に対して３０゜の角度になるように
取り付けられている。Reference numeral 18 denotes a member characteristic of this embodiment, that is, a scraper made of a polyester film (thickness 150 μm, tip end portion) provided for removing the magnetic particles 23 on the charging electrode roller 20 from the charging electrode roller 20. The free length is 3 mm), and as shown in FIG.
It is attached at a position rotated by 45 ° to the downstream side in the moving direction of the charging electrode roller 20 from the closest position of the photosensitive member 19 and the charging electrode roller 20 on the 0 surface so as to form an angle of 30 ° with respect to the tangential direction.

【００３２】２７は信号光、２８は現像剤溜め、２９は
絶縁性磁性１成分現像剤、３０は感光体１９と３００μ
ｍのギャップを開けて設定した現像電極ローラ、３１は
現像電極ローラ３０の内部に設置された磁石、３２は感
光体１９内部に固定された磁石、３３は現像電極ローラ
３０に電圧を印加する交流高圧電源、３４は現像電極ロ
ーラ上の現像剤をかきおとすポリエステルフィルム製の
スクレーパ、３５は感光体上のトナー像を紙に転写する
転写ローラである。現像電極ローラ３０は周速６０ｍｍ
／ｓで感光体の進行方向とは逆方向（図２の矢印方向）
に回転させるようにした。27 is a signal light, 28 is a developer reservoir, 29 is an insulating magnetic one-component developer, 30 is a photoconductor 19 and 300 μm.
A developing electrode roller set with a gap of m, 31 is a magnet installed inside the developing electrode roller 30, 32 is a magnet fixed inside the photoconductor 19, and 33 is an alternating current for applying a voltage to the developing electrode roller 30. A high-voltage power source, 34 is a scraper made of a polyester film for scraping off the developer on the developing electrode roller, and 35 is a transfer roller for transferring the toner image on the photoconductor onto paper. The developing electrode roller 30 has a peripheral speed of 60 mm.
/ S is the direction opposite to the direction of travel of the photoconductor (the direction of the arrow in Fig. 2)
I made it rotate.

【００３３】磁性１成分現像剤２９には粒径５μｍの微
粒子絶縁性磁性１成分トナーを用いた。磁性１成分トナ
ーの構成は、ポリエステル樹脂７０％、フェライト２５
％、カーボンブラック３％、オキシカルボン酸金属錯体
２％からなり、さらにコロイダルシリカを１％外添して
用いた（いずれも重量％）。As the magnetic one-component developer 29, a fine particle insulating magnetic one-component toner having a particle diameter of 5 μm was used. The composition of the magnetic one-component toner is 70% polyester resin and 25 ferrite.
%, Carbon black 3%, oxycarboxylic acid metal complex 2%, and 1% of colloidal silica was added externally (all in weight%).

【００３４】上記構成において画像出力開始とともに感
光体１９が回転を開始してから高圧電源２４により帯電
電極ローラ２０に、周波数１ｋＨｚ、電圧１ｋＶ（ピー
ク・ツー・ピーク）、重畳直流電圧−６００Ｖの電圧を
印加したところ、感光体１９は−５００Ｖに帯電した。
このとき感光体１９の表面電位のバラツキは、スクレー
パがないときと比べて約半分の±１０Ｖ程度であった。
この感光体１９に信号光２７を照射し静電潜像を形成し
た。このとき感光体の露光電位は−９０Ｖであった。こ
の感光体１９表面上に、現像剤２９を現像剤溜め２８内
で磁力により付着させた。次に感光体１９を高圧電源３
３により周波数１．８ｋＨｚ、電圧１．５ｋＶ（ピーク
・ツー・ピーク）、重畳直流電圧−３００Ｖの電圧を印
加され感光体１９と逆方向に回転している現像電極ロー
ラ３０の前を通過させた。すると感光体１９の帯電部分
に付着したトナーは現像電極ローラ３０に回収され、感
光体１９上には画像部にのみネガポジ反転したトナー像
が残った。こうして感光体１９上に得られたトナー像
を、紙（図示せず）に、転写ローラ３５によって転写し
た後、定着器（図示せず）により熱定着した。このと
き、帯電電極ローラ２０近傍からのオゾン発生はほとん
ど観察されなかった。In the above structure, after the photoconductor 19 starts to rotate upon the start of image output, the charging electrode roller 20 is supplied to the charging electrode roller 20 by the high-voltage power source 24 at a frequency of 1 kHz, a voltage of 1 kV (peak-to-peak), and a superimposed DC voltage of -600 V. Then, the photoconductor 19 was charged to −500V.
At this time, the variation in the surface potential of the photoconductor 19 was about ± 10 V, which is about half that in the case without the scraper.
The photoconductor 19 was irradiated with the signal light 27 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -90V. The developer 29 was magnetically attached to the surface of the photoreceptor 19 in the developer reservoir 28. Next, the photoreceptor 19 is connected to the high voltage power source 3
3, a frequency of 1.8 kHz, a voltage of 1.5 kV (peak-to-peak), and a superimposed DC voltage of -300 V were applied and passed in front of the developing electrode roller 30 rotating in the opposite direction to the photoconductor 19. . Then, the toner adhering to the charged portion of the photoconductor 19 was collected by the developing electrode roller 30, and the negative-positive inverted toner image remained only on the image portion on the photoconductor 19. The toner image thus obtained on the photoconductor 19 was transferred onto paper (not shown) by the transfer roller 35, and then heat-fixed by a fixing device (not shown). At this time, almost no ozone generation was observed in the vicinity of the charging electrode roller 20.

【００３５】このようにスクレーパ１８を取り付ける
と、スクレーパがないときと比べて帯電電位が安定す
る。さらに、低温低湿下の悪条件で画像を出力したとき
でも磁性粒子が感光体１９に付着することがなく、特に
効果的であった。また、装置が振動したときでも、帯電
電極ローラ２０から磁性粒子２３がこぼれて装置内を汚
染することはなくなった。When the scraper 18 is attached in this manner, the charging potential becomes more stable than when the scraper is not provided. Furthermore, even when an image was output under adverse conditions of low temperature and low humidity, magnetic particles did not adhere to the photoconductor 19, which was particularly effective. Further, even when the device vibrates, the magnetic particles 23 do not spill from the charging electrode roller 20 and contaminate the inside of the device.

【００３６】なお、本発明ではスクレーパ１８の材料と
してポリエステルフィルムを用いたが、たとえば肉厚が
薄いリン青銅板やステンレス板のような金属でも本発明
の本質と作用効果は変わることはない。（実施例３）図３の構成は図２の構成と、帯電電極ロー
ラ３６内部に設けた固定磁石３７を帯電電極ローラ３６
表面で隣接する互いに異なる２つの磁束密度のピークを
発生する固定磁石３６に変更した点が異なる。以下、図
３に示した帯電装置について説明する。Although the polyester film is used as the material of the scraper 18 in the present invention, the essence and the function and effect of the present invention are not changed even if the metal is thin such as phosphor bronze plate or stainless plate. (Embodiment 3) The configuration of FIG. 3 differs from that of FIG. 2 in that the fixed magnet 37 provided inside the charging electrode roller 36
The difference is that a fixed magnet 36 that generates two different magnetic flux density peaks adjacent to each other on the surface is used. Hereinafter, the charging device shown in FIG. 3 will be described.

【００３７】図３において、３７はフタロシアニンをポ
リエステル系バインダ樹脂に分散した有機のドラム状の
感光体（外径３０ｍｍ）、３８はステンレス製の帯電電
極ローラ（外径１６ｍｍ、内径１５ｍｍ）、３６は帯電
電極ローラ３８と同軸で固定され互いに異なる２つの磁
束密度のピークを持つ固定磁石（外周半径７ｍｍ）、３
９は表面をシリコンコートした粒径３０μｍの磁性粒子
４０が形成する粒子溜まり、４１は帯電電極ローラ３８
に電圧を印加する交流高圧電源である。４２は磁性粒子
４０を内包するホッパ、４３は磁性粒子４０がホッパ４
２からのこぼれを防ぐ薄いポリエステルフィルム製のシ
ール材で、一方の先端が感光体３７表面に接触するよう
にホッパ４２の先端部分に取り付けられている。帯電電
極ローラ３８と感光体３７との距離は３５０μｍに設定
した。感光体３７は、周速６０ｍｍ／ｓで図３の矢印方
向に回転するようにした。帯電電極ローラ３８は周速１
２０ｍｍ／ｓで感光体の進行方向とは逆方向（図３の矢
印方向）に回転させるようにした。In FIG. 3, 37 is an organic drum-shaped photosensitive member (outer diameter 30 mm) in which phthalocyanine is dispersed in polyester binder resin, 38 is a charging electrode roller (outer diameter 16 mm, inner diameter 15 mm) made of stainless steel, and 36 is A fixed magnet (periphery radius 7 mm) which is fixed coaxially with the charging electrode roller 38 and has two different magnetic flux density peaks, 3
Reference numeral 9 denotes a particle pool formed by magnetic particles 40 having a particle size of 30 μm and having a surface coated with silicon, and 41 denotes a charging electrode roller 38.
It is an AC high voltage power supply that applies a voltage to. 42 is a hopper containing the magnetic particles 40, and 43 is the hopper 4 containing the magnetic particles 40.
A sealing material made of a thin polyester film that prevents spillage from the hopper 2, and is attached to the tip portion of the hopper 42 so that one tip is in contact with the surface of the photoconductor 37. The distance between the charging electrode roller 38 and the photoconductor 37 was set to 350 μm. The photoconductor 37 was rotated in the direction of the arrow in FIG. 3 at a peripheral speed of 60 mm / s. The peripheral speed of the charging electrode roller 38 is 1
At a speed of 20 mm / s, the photoconductor was rotated in the direction opposite to the traveling direction (direction of arrow in FIG. 3).

【００３８】図１０に磁石３６による帯電電極ローラ３
８表面の垂直方向の磁束密度の分布を示す。図１０では
感光体３７と帯電電極ローラ３８の最近接部分を０゜と
して、帯電電極ローラ３８の回転移動方向の上流側（感
光体３７の移動方向の下流側）を−側、帯電電極ローラ
３８の回転移動方向の下流側（感光体３７の移動方向の
上流側）を＋側として示している。固定磁石３６による
帯電電極ローラ３８表面でのピーク磁束密度は０゜の部
分に６００Ｇs（Ｎ極）、＋４０゜の部分に４００Ｇs
（Ｓ極）であった。FIG. 10 shows the charging electrode roller 3 using the magnet 36.
8 shows the distribution of the magnetic flux density in the vertical direction on the surface. In FIG. 10, the closest portion between the photoconductor 37 and the charging electrode roller 38 is set to 0 °, the upstream side in the rotational movement direction of the charging electrode roller 38 (downstream side in the moving direction of the photoconductor 37) is the − side, and the charging electrode roller 38 is. The downstream side (the upstream side in the moving direction of the photoconductor 37) in the rotational movement direction of is shown as the + side. The peak magnetic flux density on the surface of the charging electrode roller 38 by the fixed magnet 36 is 600 Gs (N pole) at 0 ° and 400 Gs at + 40 °.
(S pole).

【００３９】図３において４４は帯電電極ローラ３８上
の磁性粒子４０を帯電電極ローラ３８上から取り除くた
めに設けられたポリエステルフィルム製のスクレーパ
（厚さ１５０μｍ、先端部自由長３ｍｍ）で、帯電電極
ローラ３８表面で感光体３７と帯電電極ローラ３８の最
近接位置から帯電電極ローラ３８の移動方向下流側に４
５゜回転した位置に接線方向に対して３０゜の角度にな
るように取り付けられている。In FIG. 3, reference numeral 44 denotes a polyester film scraper (thickness 150 μm, free end length 3 mm) provided for removing the magnetic particles 40 on the charging electrode roller 38 from the charging electrode roller 38. 4 from the closest position of the photoconductor 37 and the charging electrode roller 38 on the surface of the roller 38 to the downstream side in the moving direction of the charging electrode roller 38.
It is attached at a position rotated by 5 ° to form an angle of 30 ° with respect to the tangential direction.

【００４０】４５は信号光、４６は現像剤溜め、４７は
絶縁性磁性１成分現像剤、４８は感光体３７と３００μ
ｍのギャップを開けて設定した現像電極ローラ、４９は
現像電極ローラ４８の内部に設置された磁石、５０は感
光体３７内部に固定された磁石、５１は現像電極ローラ
４８に電圧を印加する交流高圧電源、５２は現像電極ロ
ーラ上の現像剤をかきおとすポリエステルフィルム製の
スクレーパ、５３は感光体上のトナー像を紙に転写する
転写ローラである。現像電極ローラ４８は周速６０ｍｍ
／ｓで感光体の進行方向とは逆方向（図３の矢印方向）
に回転させるようにした。Reference numeral 45 is a signal light, 46 is a developer reservoir, 47 is an insulating magnetic one-component developer, 48 is a photoreceptor 37 and 300 μm.
A developing electrode roller set with a gap of m, 49 is a magnet installed inside the developing electrode roller 48, 50 is a magnet fixed inside the photoconductor 37, and 51 is an alternating current for applying a voltage to the developing electrode roller 48. A high-voltage power source, 52 is a scraper made of a polyester film for scraping off the developer on the developing electrode roller, and 53 is a transfer roller for transferring the toner image on the photoconductor to paper. The developing electrode roller 48 has a peripheral speed of 60 mm.
/ S is the direction opposite to the direction of travel of the photoconductor (the direction of the arrow in Fig. 3)
I made it rotate.

【００４１】磁性１成分現像剤４７には粒径５μｍの微
粒子絶縁性磁性１成分トナーを用いた。磁性１成分トナ
ーの構成は、ポリエステル樹脂７０％、フェライト２５
％、カーボンブラック３％、オキシカルボン酸金属錯体
２％からなり、さらにコロイダルシリカを１％外添して
用いた（いずれも重量％）。As the magnetic one-component developer 47, fine particle insulating magnetic one-component toner having a particle size of 5 μm was used. The composition of the magnetic one-component toner is 70% polyester resin and 25 ferrite.
%, Carbon black 3%, oxycarboxylic acid metal complex 2%, and 1% of colloidal silica was added externally (all in weight%).

【００４２】上記構成において画像出力開始とともに感
光体３７が回転を開始してから高圧電源４１により帯電
電極ローラ３８に、周波数１ｋＨｚ、電圧１ｋＶ（ピー
ク・ツー・ピーク）、重畳直流電圧−６００Ｖの電圧を
印加したところ、感光体３７は−５００Ｖに帯電した。
この感光体３７に信号光４５を照射し静電潜像を形成し
た。このとき感光体の露光電位は−９０Ｖであった。こ
の感光体３７表面上に、現像剤４７を現像剤溜め４６内
で磁力により付着させた。次に感光体３７を高圧電源５
１により周波数１．８ｋＨｚ、電圧１．５ｋＶ（ピーク
・ツー・ピーク）、重畳直流電圧−３００Ｖの電圧を印
加され感光体３７と逆方向に回転している現像電極ロー
ラ４８の前を通過させた。すると感光体３７の帯電部分
に付着したトナーは現像電極ローラ４８に回収され、感
光体３７上には画像部にのみネガポジ反転したトナー像
が残った。こうして感光体３７上に得られたトナー像
を、紙（図示せず）に、転写ローラ５３によって転写し
た後、定着器（図示せず）により熱定着した。このと
き、帯電電極ローラ３８近傍からのオゾン発生はほとん
ど観察されなかった。In the above-mentioned structure, the voltage of 1 kHz, voltage 1 kV (peak-to-peak), and superimposed DC voltage -600 V is applied to the charging electrode roller 38 by the high voltage power supply 41 after the photoconductor 37 starts to rotate at the same time when the image output is started. Then, the photoconductor 37 was charged to −500V.
The photoconductor 37 was irradiated with the signal light 45 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -90V. The developer 47 was magnetically attached to the surface of the photoconductor 37 in the developer reservoir 46. Next, the photoconductor 37 is connected to the high voltage power source 5
1, a frequency of 1.8 kHz, a voltage of 1.5 kV (peak-to-peak), and a superimposed DC voltage of -300 V were applied and passed in front of the developing electrode roller 48 rotating in the opposite direction to the photoconductor 37. . Then, the toner adhering to the charged portion of the photoconductor 37 was collected by the developing electrode roller 48, and a negative-positive inverted toner image remained only on the image portion on the photoconductor 37. The toner image thus obtained on the photoconductor 37 was transferred onto paper (not shown) by the transfer roller 53, and then heat-fixed by a fixing device (not shown). At this time, almost no ozone generation was observed from the vicinity of the charging electrode roller 38.

【００４３】このように、２つの磁束密度のピークを有
するようにすると、表面電位のバラツキがピークが１つ
のときと比べて半分の±５Ｖ程度に抑えられ効果的であ
る。さらに、磁性粒子を細かくしたときでも容易に搬送
することができ、特に効果的であった。Thus, having two peaks of the magnetic flux density is effective because the variation of the surface potential is suppressed to about ± 5 V, which is half that in the case where there is one peak. Furthermore, it was particularly effective because the magnetic particles could be easily transported even when they were made fine.

【００４４】なお、本発明では帯電電極ローラ内の固定
磁石に互いに異なる２つの極性の磁束密度のピークを有
する磁石を用いたが、この磁石の代わりに、たとえば図
１１に示す３つの磁束密度のピークを持つ磁石Ｃのよう
に、帯電電極ローラ表面上で感光体と帯電電極ローラと
の最近接部とスクレーパまでの間に３つ以上の磁束密度
のピークを持つ磁石を用いても本発明の本質と作用効果
は変わることはない。In the present invention, a magnet having two different magnetic flux density peaks is used as the fixed magnet in the charging electrode roller. Instead of this magnet, for example, three magnetic flux densities shown in FIG. 11 are used. Even if the magnet C having three or more peaks of magnetic flux density is used between the scraper and the closest portion of the photoconductor and the charging electrode roller on the surface of the charging electrode roller, like the magnet C having the peak, the present invention can be used. The essence and effects are unchanged.

【００４５】[0045]

【発明の効果】以上の実施例の説明より明らかなよう
に、本発明は帯電電極ローラ内部に固定した固定磁石を
改良し、スクレーパを設けることにより、磁性粒子に作
用する力を改善したため（１）感光体の機械的搬送力と静電引力に負けて磁性粒
子が持ち去られることがない。As is apparent from the above description of the embodiments, the present invention improves the fixed magnet fixed inside the charging electrode roller and improves the force acting on the magnetic particles by providing a scraper. ) Magnetic particles are not taken away due to the mechanical transport force and electrostatic attraction of the photoconductor.

【００４６】（２）感光体と磁性粒子の接触が安定する
ため均質で安定な帯電を行える。（３）装置が振動しても帯電電極ローラから磁性粒子が
こぼれ落ちないようになる。(2) Since the contact between the photosensitive member and the magnetic particles is stable, uniform and stable charging can be performed. (3) Magnetic particles are prevented from spilling from the charging electrode roller even when the device vibrates.

【００４７】その結果、小型でしかもオゾンの発生量が
少なく高画質の得られる帯電装置を得ることができる。As a result, it is possible to obtain a charging device which is small in size, produces a small amount of ozone, and can obtain high image quality.

【図面の簡単な説明】[Brief description of drawings]

【図１】本発明の第１の実施例の帯電装置の構成図FIG. 1 is a configuration diagram of a charging device according to a first embodiment of the present invention.

【図２】本発明の第２の実施例の帯電装置の構成図FIG. 2 is a configuration diagram of a charging device according to a second embodiment of the present invention.

【図３】本発明の第３の実施例の帯電装置の構成図FIG. 3 is a configuration diagram of a charging device according to a third embodiment of the present invention.

【図４】本発明の実施例における帯電電極ローラを感光
体の移動方向と逆の方向に移動させた場合の帯電電極ロ
ーラと感光体の周速比と帯電電位のバラツキの関係を示
す図FIG. 4 is a diagram showing the relationship between the peripheral speed ratio of the charging electrode roller and the photosensitive member and the variation of the charging potential when the charging electrode roller is moved in the direction opposite to the moving direction of the photosensitive member in the embodiment of the present invention.

【図５】本発明の実施例におけるスクレーパの位置と磁
性粒子の循環を示す図FIG. 5 is a diagram showing the position of a scraper and the circulation of magnetic particles in an example of the present invention.

【図６】本発明の実施例における帯電電極ローラに印加
する交流電圧の周波数と帯電電位の関係を示す図FIG. 6 is a diagram showing the relationship between the frequency of an AC voltage applied to the charging electrode roller and the charging potential in the embodiment of the present invention.

【図７】本発明の実施例における帯電電極ローラに印加
する交流電圧の振幅と帯電電位の関係を示す図FIG. 7 is a diagram showing the relationship between the amplitude of the alternating voltage applied to the charging electrode roller and the charging potential in the embodiment of the present invention.

【図８】本発明の第１の実施例において帯電に用いた固
定磁石の帯電電極ローラ表面での磁束密度分布を示す図FIG. 8 is a diagram showing a magnetic flux density distribution on the surface of the charging electrode roller of the fixed magnet used for charging in the first embodiment of the present invention.

【図９】本発明の第２の実施例において帯電に用いた固
定磁石の帯電電極ローラ表面での磁束密度分布を示す図FIG. 9 is a diagram showing the magnetic flux density distribution on the surface of the charging electrode roller of the fixed magnet used for charging in the second embodiment of the present invention.

【図１０】本発明の第３の実施例において帯電に用いた
固定磁石の帯電電極ローラ表面での磁束密度分布を示す
図FIG. 10 is a diagram showing the magnetic flux density distribution on the surface of the charging electrode roller of the fixed magnet used for charging in the third embodiment of the present invention.

【図１１】本発明の第３の実施例における帯電装置の構
成図FIG. 11 is a configuration diagram of a charging device according to a third embodiment of the present invention.

【図１２】従来の帯電装置の構成図FIG. 12 is a configuration diagram of a conventional charging device.

【符号の説明】[Explanation of symbols]

１感光体２帯電電極ローラ３固定磁石４粒子溜まり５磁性粒子６高圧電源 1 photoconductor 2 charging electrode roller 3 fixed magnet 4 particle pool 5 magnetic particles 6 high voltage power supply

Claims

【特許請求の範囲】[Claims]

【請求項１】少なくとも移動する電子写真用の感光体
の表面と所定の間隙を有した位置に設置され、進行方向
が前記感光体の進行方向と逆方向に回転する帯電電極ロ
ーラと、前記感光体と前記帯電電極ローラの隙間で粒子溜まりを
形成しながら移動する導電性の磁性粒子と、前記帯電電極ローラ内部に固定された固定磁石と、前記帯電電極ローラに電圧を印加する手段と、を有する帯電装置であって、前記固定磁石が前記感光体と前記帯電電極ローラの最近
接部に対し前記最近接部を含む前記帯電電極ローラ回転
方向の下流側に磁束密度のピークを有し、かつ上流側に
磁束密度のピークを持たないことを特徴とする帯電装
置。1. A charging electrode roller which is installed at a position having a predetermined gap from at least the surface of a moving electrophotographic photosensitive member and which rotates in a traveling direction opposite to the traveling direction of the photosensitive member. Conductive magnetic particles that move while forming a particle pool in the gap between the body and the charging electrode roller; a fixed magnet fixed inside the charging electrode roller; and means for applying a voltage to the charging electrode roller. A charging device having, wherein the fixed magnet has a peak of magnetic flux density on the downstream side in the rotation direction of the charging electrode roller including the closest portion to the closest portion of the photoconductor and the charging electrode roller, and A charging device characterized by having no peak of magnetic flux density on the upstream side.

【請求項２】固定磁石の帯電電極ローラ表面における
磁束密度のピークが１つであることを特徴とする請求項
１記載の帯電装置。2. The charging device according to claim 1, wherein there is one peak of magnetic flux density on the surface of the charging electrode roller of the fixed magnet.

【請求項３】固定磁石が帯電電極ローラ表面において
少なくとも隣合う２つの互いに異なる極性の磁束密度の
ピークを持つことを特徴とする請求項１記載の帯電装
置。3. The charging device according to claim 1, wherein the fixed magnet has at least two adjacent magnetic flux density peaks of different polarities on the surface of the charging electrode roller.

【請求項４】帯電電極ローラの周速が感光体の周速よ
り速いことを特徴とする請求項１記載の帯電装置。4. The charging device according to claim 1, wherein the peripheral speed of the charging electrode roller is faster than the peripheral speed of the photoconductor.

【請求項５】電圧印加手段による電圧の印加を感光体
の移動中のみ行うことを特徴とする請求項１記載の帯電
装置。5. The charging device according to claim 1, wherein the voltage is applied by the voltage applying means only while the photosensitive member is moving.

【請求項６】電圧印加手段による電圧の印加が所定の
電圧値に制御された直流定電圧であることを特徴とする
請求項１記載の帯電装置。6. The charging device according to claim 1, wherein the voltage applied by the voltage applying means is a constant DC voltage controlled to a predetermined voltage value.

【請求項７】電圧印加手段による電圧の印加が所定の
電流値に制御された直流定電流であることを特徴とする
請求項１記載の帯電装置。7. The charging device according to claim 1, wherein the voltage applied by the voltage applying means is a direct current constant controlled to a predetermined current value.

【請求項８】電圧印加手段による電圧の印加が交流成
分を有することを特徴とする請求項１記載の帯電装置。8. The charging device according to claim 1, wherein the voltage application by the voltage application means has an AC component.

【請求項９】少なくとも移動する電子写真用の感光体
の表面と所定の間隙を有した位置に設置され、進行方向
が前記感光体の進行方向と逆方向に回転する帯電電極ロ
ーラと、前記感光体と前記帯電電極ローラの隙間で粒子溜まりを
形成しながら移動する導電性の磁性粒子と、前記帯電電極ローラ内部に固定された固定磁石と、前記帯電電極ローラに電圧を印加する手段を備え、前記帯電電極ローラの回転にともなって移動する前記磁
性粒子を前記帯電電極ローラ上から除去するスクレーパ
を設けたことを特徴とする帯電装置。9. A charging electrode roller which is installed at a position having at least a predetermined gap from a surface of a moving electrophotographic photosensitive member and which rotates in a traveling direction opposite to a traveling direction of the photosensitive member, and the photosensitive member. Conductive magnetic particles that move while forming a particle pool in the gap between the body and the charging electrode roller; a fixed magnet fixed inside the charging electrode roller; and means for applying a voltage to the charging electrode roller, A charging device comprising a scraper for removing the magnetic particles, which move with the rotation of the charging electrode roller, from the charging electrode roller.

【請求項１０】スクレーパが感光体と帯電電極ローラ
の最近接部から前記電極ローラ回転方向に対する下流側
に９０゜以内の位置で前記電極ローラと接触することを
特徴とする請求項９記載の帯電装置。10. The charging device according to claim 9, wherein the scraper comes into contact with the electrode roller at a position within 90 ° from the closest portion of the photosensitive member and the charging electrode roller to the downstream side with respect to the rotation direction of the electrode roller. apparatus.