JP3281139B2 - Charging device - Google Patents
Charging deviceInfo
- Publication number
- JP3281139B2 JP3281139B2 JP23902693A JP23902693A JP3281139B2 JP 3281139 B2 JP3281139 B2 JP 3281139B2 JP 23902693 A JP23902693 A JP 23902693A JP 23902693 A JP23902693 A JP 23902693A JP 3281139 B2 JP3281139 B2 JP 3281139B2
- Authority
- JP
- Japan
- Prior art keywords
- charging
- magnet body
- magnet
- magnetic
- charging device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は粒子帯電によりベルト状
若しくはドラム状感光体を帯電させる電子写真装置に於
け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 in an electrophotographic apparatus for charging a belt-shaped or drum-shaped photosensitive member by particle charging.
【０００２】[0002]
【従来の技術】従来より感光体ドラム外周面上に、露
光、現像、転写、クリーニング（残留トナー除去）、除
電、及び帯電の各プロセス手段を配置し、所定の電子写
真プロセスにより画像形成を行なう、いわゆるカールソ
ンプロセスに基づく画像形成装置は周知である。2. Description of the Related Art Conventionally, respective process means of exposure, development, transfer, cleaning (removal of residual toner), charge elimination and charging are arranged on the outer peripheral surface of a photosensitive drum, and an image is formed by a predetermined electrophotographic process. Image forming apparatuses based on the so-called Carlson process are well known.
【０００３】又近年、円筒状の透光性支持体上に透光性
導電層と光導電体層を積層して感光体ドラムを形成する
と共に、該ドラム内に、画像情報に対応した光出力を生
成する露光手段（例えばＬＥＤヘッド）を内挿し、所定
の帯電手段を用いて帯電させた感光体ドラム上に前記露
光手段の光出力を集束レンズを通して露光すると同時若
しくはその直後に前記感光体ドラムと対面配置させた現
像スリーブを介して前記潜像をトナー像化（現像）した
後、該トナー像を転写ローラその他の転写手段を介して
記録紙に転写可能に構成した画像形成装置（特開昭５８
−１５３９５７号他）も公知である。In recent years, a photoconductive drum is formed by laminating a light-transmitting conductive layer and a photoconductive layer on a cylindrical light-transmitting support, and a light output corresponding to image information is formed in the drum. Exposure means (e.g., an LED head) for generating an image is interpolated and the light output of the exposure means is exposed through a converging lens onto the photosensitive drum charged using a predetermined charging means at the same time as or immediately after the exposure. An image forming apparatus configured to transfer (transfer) the toner image to a recording sheet via a transfer roller or other transfer means after forming the latent image into a toner image (development) via a developing sleeve arranged to face the image forming apparatus 1958
153957) are also known.
【０００４】この種の装置に用いる帯電手段は一般に細
いタングステン線に高電圧を印加してコロナ放電を行な
うコロトロン方式、又導電ローラに数百ボルトの電圧を
かけて感光体ドラムと接触帯電させるもの、又導電性ブ
ラシに電圧を印加して感光体ドラムに接触させながら帯
電を行なうもの等が存在する。しかしながらコロトロン
方式は高電圧を使用し、又オゾンを発生する等安全上、
環境上の問題が多い。又帯電ローラは感光体ドラムとの
接触が線接触であるために帯電が不安定である。更にブ
ラシ帯電方式はドラムとブラシが接触して帯電を行なう
為に、ブラシの帯電劣化が生じやすい。The charging means used in this type of apparatus is generally a corotron type in which a high voltage is applied to a thin tungsten wire to perform corona discharge, or a charging means in which a voltage of several hundred volts is applied to a conductive roller to contact and charge a photosensitive drum. In addition, there is a type in which a voltage is applied to a conductive brush while being brought into contact with a photosensitive drum to charge the conductive brush. However, the corotron method uses high voltage and generates ozone for safety reasons.
Many environmental problems. Further, the charging roller is unstable in charging because the contact with the photosensitive drum is a line contact. Further, in the brush charging method, the charging of the brush is likely to occur because the drum and the brush are in contact with each other to perform charging.
【０００５】かかる欠点を解消するために、図５に示す
ように、感光体ドラム１０１と磁石集成体１０２を内挿
した非磁性スリーブ１０３を用い、該スリーブ１０３に
帯電バイアス１０８を印加した状態で、該スリーブ１０
３に磁性粒子群１０４を付着させて刷子状の磁気穂を感
光体ドラム１０１に摺擦させてスリーブ１０３を介して
帯電バイアス１０８を磁性粒子群１０４に印加させて帯
電を行なう、いわゆる粒子帯電法が提案されている。
（特開昭５９ー１３３５６９、特開昭６３ー１８７２６
７他）In order to eliminate such a defect, as shown in FIG. 5, a non-magnetic sleeve 103 having a photosensitive drum 101 and a magnet assembly 102 inserted therein is used, and a charging bias 108 is applied to the sleeve 103. , The sleeve 10
3 is a so-called particle charging method in which a magnetic particle group 104 is adhered to the brush 3 and a brush-shaped magnetic spike is rubbed against the photosensitive drum 101 to apply a charging bias 108 to the magnetic particle group 104 via a sleeve 103 to perform charging. Has been proposed.
(JP-A-59-133569, JP-A-63-18726)
7 others)
【０００６】かかる帯電法において導電性微粒子により
感光体ドラム１０１を均一帯電させるには前記帯電領域
における磁性粒子群１０４と感光体ドラム１０１との接
触面積及び接触密度を十分な条件にする必要があるが、
磁気刷子の接触面積は感光体ドラム１と磁石集成体１０
２を内挿した非磁性スリーブ１０３の外径によって決っ
てしまい、この為前記感光体ドラム１０１やスリーブ１
０３を小型にすればするほど接触ニップが狭くなり、而
も感光体ドラム１０１の回転速度も大になるために、接
触ニップが不安定化しやすい。In order to uniformly charge the photosensitive drum 101 with the conductive fine particles in such a charging method, the contact area and the contact density between the magnetic particle group 104 and the photosensitive drum 101 in the charged area must be set to sufficient conditions. But,
The contact area of the magnetic brush depends on the photosensitive drum 1 and the magnet assembly 10.
2 is determined by the outer diameter of the non-magnetic sleeve 103 in which the photosensitive drum 101 and the sleeve 1 are inserted.
The smaller the size of 03, the narrower the contact nip and the higher the rotation speed of the photosensitive drum 101, the more easily the contact nip becomes unstable.
【０００７】この為、本出願人は先に特願平５ー１３９
８３１号において、図４（図４は本発明が開示されてい
る。）に示すように、感光体ドラム１の帯電領域背面側
に、感光体ドラム回転方向に沿って極性の異なる第１及
び第２の磁石体５Ａ、５Ｂを隣接配置し、該２つの磁石
体５Ａ、５Ｂ間の感光体ドラム１上に水平磁場を形成さ
せるとともに、感光体ドラム１回転方向下流側に位置す
る第１の磁石体５Ａとほぼ対向させて感光体ドラム１上
方位置に帯電スリーブ３を介して前記第１の磁石体５Ａ
と逆極性の固定磁石体２Ａを配設した帯電装置を提案し
ている。かかる先願技術によれば、前記水平磁場によ
り、前記磁性粒子群４を感光体ドラム１上に密着させて
帯電させることが出来、前記対向配置される第１の磁石
体５Ａと非磁性の帯電スリーブ３に内包された磁石集成
体２の固定磁石体２Ａを感光体１移動方向における帯電
領域下流側に配することにより、いわゆる垂直磁気バリ
アが帯電領域の下流側に形成できるために、感光体ドラ
ム１に静電的に付着した磁性粒子４が帯電領域外へ洩出
するのを防ぐ事が出来るものである。[0007] For this reason, the present applicant has previously filed Japanese Patent Application No. 5-139.
No. 831, as shown in FIG. 4 (FIG. 4 discloses the present invention), on the back side of the charged area of the photosensitive drum 1, first and second polarities different in polarity along the photosensitive drum rotation direction. Two magnet bodies 5A and 5B are arranged adjacent to each other to form a horizontal magnetic field on the photosensitive drum 1 between the two magnet bodies 5A and 5B, and a first magnet positioned downstream of the photosensitive drum 1 in the rotation direction. The first magnet body 5A is located at a position above the photosensitive drum 1 through the charging sleeve 3 so as to be substantially opposed to the body 5A.
A charging device provided with a fixed magnet body 2A having a polarity opposite to that of the charging device is proposed. According to the prior art, the magnetic field group 4 can be brought into close contact with the photosensitive drum 1 and charged by the horizontal magnetic field, and the non-magnetic charging can be performed with the first magnet body 5A disposed opposite to the first magnet body 5A. By disposing the fixed magnet body 2A of the magnet assembly 2 contained in the sleeve 3 on the downstream side of the charged area in the moving direction of the photoreceptor 1, a so-called vertical magnetic barrier can be formed on the downstream side of the charged area. It is possible to prevent the magnetic particles 4 electrostatically attached to the drum 1 from leaking out of the charged area.
【０００８】[0008]
【発明が解決しようとする課題】従って前記の装置にお
いては磁性粒子の磁気保持を行なう磁石体が現像ギャッ
プの片側にのみ配置されているのではなく、両側に配置
されている為に、帯電ギャップ間の磁化力（ΔＨ／Δ
ｔ）をほぼ均一に設定でき、、安定した磁性粒子群４の
磁気保持力を維持でき、更には垂直磁気バリアにより帯
電領域位置における磁性粒子の洩出は阻止することは出
来るが、感光体背面側に磁石体５Ａ、５Ｂを配設する構
成を取るために、前記磁石体の軸端側における感光体ド
ラム１上の帯電領域と非帯電領域間の境界線上に形成さ
れる電位差が、垂直に立ち下がるように形成されるため
に、その部分で感光体の移動方向に沿って粒子引きとよ
ばれる漏洩現象が生じ、次工程の露光及び現像等に悪影
響を及ぼす。かかる欠点を解消するために、図５に示す
従来技術の帯電領域の感光体移動方向下流側にブレード
を配して磁性粒子を回収するように構成する事も考えら
れるが、かかる構成を取ると、長期使用を可能にする為
に前記ブレードに付着した磁性粒子を回収する機構が必
要になり、構成が煩雑化する。Therefore, in the above-described apparatus, the magnet body for holding the magnetic particles is not disposed only on one side of the developing gap but on both sides thereof. Magnetization force (ΔH / Δ
t) can be set substantially uniform, the stable magnetic coercive force of the magnetic particle group 4 can be maintained, and the leakage of the magnetic particles at the charged area position can be prevented by the perpendicular magnetic barrier. In order to adopt a configuration in which the magnets 5A and 5B are disposed on the side, the potential difference formed on the boundary between the charged region and the non-charged region on the photosensitive drum 1 on the shaft end side of the magnet is vertically Since the photoreceptor is formed so as to fall, a leakage phenomenon called particle pulling occurs in the portion along the moving direction of the photoreceptor, which adversely affects the exposure and development in the next step. In order to solve such a drawback, it is conceivable to employ a configuration in which a blade is disposed on the downstream side of the photosensitive member in the moving direction of the photoconductor in the prior art shown in FIG. 5 to collect the magnetic particles. In order to enable long-term use, a mechanism for collecting the magnetic particles attached to the blade is required, and the configuration becomes complicated.
【０００９】本発明はかかる従来技術の欠点に鑑み、前
記磁石体軸端側における粒子引きを有効に阻止し得る帯
電装置を提供する事を目的とする。SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to provide a charging device capable of effectively preventing particle pulling at the shaft end of the magnet body.
【００１０】[0010]
【課題を解決する為の手段】本発明は、感光体背面側に
一又は複数の磁石体を配置し、該磁石体若しくは他の磁
石体との協動作用で感光体表面の帯電領域上に保持され
た磁性粒子群を介して感光体を帯電可能に構成した感光
体の帯電装置において、感光体ドラムの帯電領域内に対
向させて、非磁性の帯電スリーブの背面側に固定磁石体
を固定配置するとともに、これと逆極性である感光体帯
電領域下流側の感光体背面側に位置する磁石体（以下第
１の磁石体という）の少なくとも軸端側の、前記感光ド
ラムと帯電スリーブ間に形成される空間上に前記第１の
磁石体と同極性の第２の磁石体を配設し、該第２の磁石
体が前記帯電スリーブを挟んで固定磁石体と、及び感光
体を挟んで第１の磁石体と夫々ほぼ対向するごとく配置
した事を特徴とし、好ましくは感光体ドラムと帯電スリ
ーブの回転方向が逆方向である請求項１記載の感光体の
帯電装置において、前記第２の磁石体が帯電ローラ回転
方向の帯電位置下流側の感光体ドラム表面上空間に配置
されている事を特徴とする。感光体背面側に一又は複数
の磁石体を配置し、該磁石体若しくは他の磁石体との協
動作用で感光体表面の帯電領域上に保持された磁性粒子
群を介して感光体を帯電可能に構成した感光体の帯電装
置に適用されるもので、その特徴とするところは、感光
体ドラムの帯電領域内に所定ギャップを介して感光ドラ
ム１に対向する帯電スリーブ３の背面側に固定磁石体を
固定配置するとともに、これと逆極性である感光体帯電
領域下流側の感光体背面側に位置する磁石体（以下第１
の磁石体という）の少なくとも軸端側に、前記磁石体と
感光体を挟んでほぼ対向するごとく前記第１の磁石体と
同極性の第２の磁石体を配設した事にある。これにより
一対の同極性の磁極からなる反発磁界により帯電領域軸
端側の磁性粒子の漏洩（粒子引き）を阻止し帯電領域側
に粒子を維持することが可能である。この場合前記粒子
引きは帯電領域と非帯電領域の境界線上に発生するため
に、前記第２の磁石体が、感光体軸端側の帯電領域とそ
の外側の非帯電領域との間の境界線上を跨がって配置さ
せ、更にその軸端が第１の磁石体の外端面より僅かに外
方に位置するまで感光体軸方向全域に亙って延在させる
のがよい。According to the present invention, one or a plurality of magnets are arranged on the back side of a photoreceptor, and the magnets or other magnets cooperate with the magnets on a charged area on the surface of the photoreceptor. In a photoconductor charging device configured to be capable of charging the photoconductor via the held magnetic particles, a fixed magnet body is fixed to the back side of the non-magnetic charging sleeve so as to face the charging area of the photoconductor drum. And a magnet body (hereinafter, referred to as a first magnet body) located on the back side of the photoconductor downstream of the photoconductor charging area having the opposite polarity to at least the shaft end between the photoconductor drum and the charging sleeve. A second magnet body having the same polarity as the first magnet body is disposed on the space formed, and the second magnet body is fixed to the fixed magnet body with the charging sleeve interposed therebetween and the second magnet body with the photoconductor interposed therebetween. Characterized in that they are arranged so as to be substantially opposed to the first magnet body, respectively. 2. The photoconductor charging device according to claim 1, wherein the rotation direction of the photoconductor drum and the charging sleeve is opposite to each other, wherein the second magnet is disposed on the surface of the photoconductor drum downstream of the charging position in the rotation direction of the charging roller. It is characterized by being arranged in space. One or a plurality of magnets are arranged on the back side of the photoreceptor, and the photoreceptor is charged through magnetic particles held on a charged area on the surface of the photoreceptor for cooperating with the magnet or another magnet. The present invention is applied to a photoconductor charging device configured to be capable of being fixed to a rear surface of a charging sleeve 3 facing the photoconductor drum 1 with a predetermined gap in a charging area of the photoconductor drum. A magnet body is fixedly disposed, and a magnet body (hereinafter referred to as a first body) located on the back side of the photosensitive body downstream of the photosensitive body charging area having the opposite polarity to the magnet body.
At least at the shaft end of the second magnet body, a second magnet body having the same polarity as the first magnet body is disposed so as to be substantially opposed to the magnet body with the photoconductor interposed therebetween. This makes it possible to prevent leakage (particle pulling) of the magnetic particles on the axial end side of the charged area by the repulsive magnetic field composed of a pair of magnetic poles of the same polarity, and maintain the particles on the charged area side. In this case, since the particle pulling occurs on the boundary between the charged region and the non-charged region, the second magnet body is positioned on the boundary between the charged region on the photoconductor shaft end side and the non-charged region outside the charged region. It is preferable that the shaft end is extended over the entire area in the axial direction of the photoconductor until the shaft end is located slightly outside the outer end surface of the first magnet body.
【００１１】又前記第２の磁石体を、感光体軸端側の帯
電領域とその外側の非帯電領域との間の境界線上を跨が
って配置させ、更にその軸端が第１の磁石体の外端面よ
り僅かに外方に位置するまで感光体軸方向全域に亙って
延在させる事により、感光体軸方向全幅に亙る感光体ド
ラム下流側への磁性粒子の漏洩を阻止し帯電領域側に粒
子を維持することが可能であるために、ブレード等を用
いなくても帯電領域からの洩出を有効に阻止し得る。更
にこの場合、前記第２の磁石体の磁力密度は前記第１の
磁石体の感光体ドラム１表面上における磁力密度より大
で且つ固定磁石体では帯電スリーブ上での磁力密度より
小になるように構成し、具体的には前記固定磁石体、前
記第１の磁石体、及び第２の磁石体の磁力密度を夫々下
記の範囲に設定するのが良い。 Ｎ＞Ｓ2＞Ｓ1、 非磁性スリーブ上における固定磁石体の磁力密度：Ｎ1 感光体上における第一の磁石体の磁力密度：Ｓ1 第二の磁石体の磁力密度：Ｓ2 Further, the second magnet body is disposed so as to straddle a boundary between a charged region on the photosensitive member shaft end side and a non-charged region outside the photosensitive member shaft end. By extending over the entire area in the axial direction of the photoconductor until it is located slightly outside the outer end surface of the body, leakage of magnetic particles to the downstream side of the photoconductor drum over the entire width in the axial direction of the photoconductor is prevented, and charging is performed. Since particles can be maintained on the region side, leakage from the charged region can be effectively prevented without using a blade or the like. Further, in this case, the magnetic force density of the second magnet body is larger than the magnetic force density of the first magnet body on the surface of the photosensitive drum 1 and smaller than the magnetic force density of the fixed magnet body on the charging sleeve. Specifically, the magnetic force densities of the fixed magnet body, the first magnet body, and the second magnet body are preferably set in the following ranges, respectively. N> S 2 > S 1 , the magnetic density of the fixed magnet on the non-magnetic sleeve: N 1 The magnetic density of the first magnet on the photoreceptor: S 1 The magnetic density of the second magnet: S 2
【００１２】即ち、前記磁力密度の設定により感光体ド
ラム表面上で帯電領域外への洩出を阻止された磁性粒子
は磁力差により固定磁石体側、即ち非磁性スリーブ側に
向い、帯電領域内での循環が可能となる。That is, the magnetic particles, which are prevented from leaking out of the charged area on the surface of the photosensitive drum by the setting of the magnetic force density, turn to the fixed magnet side, that is, the non-magnetic sleeve side due to a difference in magnetic force, and in the charged area. Circulation becomes possible.
【００１３】尚、前記粒子引きは前記したように感光体
背面側の磁石体の軸端側における感光体ドラム１上の帯
電領域と非帯電領域間の境界線上に形成される電位差が
大きくなればなるほど現れやすい。そこで請求項６及び
７記載の発明は、前記前記磁性粒子群に印加する帯電バ
イアスを４００Ｖ以下に設定して前記電位差を小さくす
ると共に、前記磁気粒子の保持を行う一又は複数の磁石
体の内、逆極性で隣接する少なくとも一の磁石体の軸端
面に磁性体を設け、磁気的エッジ効果をもたせるか、若
しくは前記少なくとも一の磁石体の軸端面と対面させて
反発磁極を設けて粒子引きを阻止するようにしている。As described above, the particle pulling is performed when the potential difference formed on the boundary between the charged region and the non-charged region on the photosensitive drum 1 at the axial end of the magnet on the back surface of the photosensitive member increases. It is easy to appear. Therefore, the invention according to claims 6 and 7 is characterized in that the charging bias applied to the magnetic particle group is set to 400 V or less to reduce the potential difference, and one or a plurality of magnet bodies for holding the magnetic particles. A magnetic body is provided on the axial end face of at least one magnet body that is adjacent in the opposite polarity, and a magnetic edge effect is provided, or a repulsive magnetic pole is provided by facing the axial end face of the at least one magnet body to perform particle pulling. I try to prevent it.
【００１４】[0014]
【実施例】以下、図面に基づいて本発明の実施例を例示
的に詳しく説明する。但しこの実施例に記載されている
構成部品の寸法、材質、形状、その相対配置などは特に
特定的な記載がない限りは、この発明の範囲をそれのみ
に限定する趣旨ではなく単なる説明例に過ぎない。図４
は本発明の実施例にかかる帯電装置の一例を示し、その
構成について説明すると、帯電装置２０は前記したよう
に図上右方向に回転する感光体ドラム１に対し帯電ギャ
ップ（０．５ｍｍ）を介して前記感光体ドラム１の回転
方向とアゲインスト方向（図上左方向）に回転可能によ
り非磁性の帯電スリーブ３を配設すると共に、該帯電ス
リーブ３の背面側の帯電領域下流側に固定配置した固定
磁石体２Ａと、該固定磁石体２Ａの帯電領域上流方向、
言換えればスリーブ回転方向下流側に、前記固定磁石体
２Ａと同極性の反発磁石体２Ｂを配設する。尚、８は不
図示の導電ブレード若しくは帯電スリーブ３を介して導
電性磁性粒子群４に帯電バイアスを印加させるバイアス
電源で、前記帯電スリーブ３を介して例えば１５０Ｖ前
後の直流帯電電位が印加される。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Not just. FIG.
1 shows an example of a charging device according to an embodiment of the present invention. The configuration of the charging device 20 will be described. As described above, the charging device 20 has a charging gap (0.5 mm) with respect to the photosensitive drum 1 rotating rightward in FIG. A non-magnetic charging sleeve 3 is disposed rotatably in the rotational direction of the photosensitive drum 1 and in the opposite direction (left direction in the figure) via the photosensitive drum 1 and fixed to the downstream side of the charging area on the back side of the charging sleeve 3. A fixed magnet body 2A disposed, a charging area upstream direction of the fixed magnet body 2A,
In other words, a repulsion magnet body 2B having the same polarity as the fixed magnet body 2A is disposed downstream of the sleeve in the rotation direction. Reference numeral 8 denotes a bias power supply for applying a charging bias to the conductive magnetic particle group 4 via a conductive blade or charging sleeve 3 (not shown). A DC charging potential of, for example, about 150 V is applied via the charging sleeve 3. .
【００１５】そして前記帯電領域上には導電性磁性粒子
群４を介在させる。該磁性粒子は導電性であれば特に限
定されないが、フェライトや鉄粉、マグネタイト等の磁
性コアの表面に導電性樹脂で被覆した導電性磁性粒子で
構成するか若しくは導電性粒子と磁性粒子の混合粒子群
４で構成してもよい。例えば平均粒径が３０μｍ前後の
磁性粒子母材と、平均粒径が１５μｍ前後の導電粒子材
を適宜割合で配合したものを用いても良い。尚、本装置
においては平均粒径が２０〜３５μｍ、抵抗率１０5〜
１０6Ω・ｃｍのフェライトコア粒子を用い、磁気特性
を６０〜７０emu／ｇ（1k Oe）に設定したものを用い
る。The conductive magnetic particles 4 are interposed on the charged area. The magnetic particles are not particularly limited as long as they are conductive.However, the magnetic particles may be made of conductive magnetic particles coated with a conductive resin on the surface of a magnetic core such as ferrite, iron powder, magnetite, or a mixture of conductive particles and magnetic particles. The particle group 4 may be used. For example, a mixture of a magnetic particle base material having an average particle size of about 30 μm and a conductive particle material having an average particle size of about 15 μm may be used. In this apparatus, the average particle size is 20 to 35 μm, and the resistivity is 10 5 to
Use is made of ferrite core particles of 10 6 Ω · cm with magnetic properties set to 60 to 70 emu / g (1 k Oe).
【００１６】一方、感光体ドラム１の背面側には、帯電
領域下流側に位置する前記固定磁石体２Ａとほぼ対向さ
せて第１の磁石体５Ａと、前記第１の磁石体５Ａに隣接
させて帯電領域上流側にＮ極の磁石体５Ｂとを隣接配置
すると共に、第１の磁石体５Ａは前記固定磁石体２Ａと
逆極性のＳ極に設定し、Ｎ極の磁石体５Ｂは該第１の磁
石体５Ａと逆極性のＮ極に設定する。この結果、前記対
向配置される第１の磁石体５Ａと固定磁石体２を感光体
ドラム１回転方向における帯電領域下流側に配し、両磁
石体２Ａ、５Ａ間に垂直磁場４Ａにより前記磁性粒子群
４Ａを磁気保持させ、又Ｎ極の磁石体５Ｂは前記第１の
磁石体５Ａに隣接させて帯電領域上流側に配置させ、前
記第１の磁石体５ＡとＮ極の磁石体５Ｂ間に主として形
成される水平磁場により前記磁性粒子群４Ｂを感光体ド
ラム１上に密着させる。On the other hand, on the back side of the photoreceptor drum 1, a first magnet body 5A is substantially opposed to the fixed magnet body 2A located on the downstream side of the charging area, and is adjacent to the first magnet body 5A. And the N-pole magnet body 5B is arranged adjacent to the upstream side of the charging area, the first magnet body 5A is set to the S-pole of the opposite polarity to the fixed magnet body 2A, and the N-pole magnet body 5B is The N pole is set to the opposite polarity to that of the first magnet body 5A. As a result, the first magnet body 5A and the fixed magnet body 2 arranged opposite to each other are arranged on the downstream side of the charging area in the rotation direction of the photosensitive drum 1, and the magnetic particles are generated between the two magnet bodies 2A and 5A by the vertical magnetic field 4A. The group 4A is magnetically held, and the N-pole magnet body 5B is arranged adjacent to the first magnet body 5A on the upstream side of the charging area, and is disposed between the first magnet body 5A and the N-pole magnet body 5B. The magnetic particle group 4B is brought into close contact with the photosensitive drum 1 by a horizontal magnetic field mainly formed.
【００１７】そして固定磁石体２Ａと同極性のＮ極に設
定した反発磁石体２Ｂは、両者間で形成される反発磁界
による無磁力帯が帯電領域上流側に位置するようにレイ
アウトし、これにより前記帯電スリーブ３に担持されて
垂直磁場４位置より帯電領域上流側に搬送された磁性粒
子群４を磁気的に開放し、感光体ドラム１側に落下する
ように構成する。そして前記夫々の磁石体の磁力は、前
記固定磁石体２Ａではスリーブ３上で８００〜１０００
ガウスの磁力が、又前記第１の磁石体５Ａは感光体ドラ
ム１表面で３００〜５００ガウス前後の磁力を得る事が
出来るように夫々設定する。又Ｎ極の磁石体５Ｂの磁力
を第１の磁石体５Ａとほぼ同等に設定する事により感光
体ドラム１表面で３００〜５００ガウス前後の磁力を得
る事が出来、更に反発磁石体２Ｂの磁力はその直上位置
でのスリーブ３上で８００〜１０００ガウスの磁力が得
られるように設定する。The repulsive magnet 2B, which is set to have the same polarity as the fixed magnet 2A and has the N pole, is laid out such that the non-magnetic force zone formed by the repulsive magnetic field formed therebetween is located on the upstream side of the charging area. The magnetic particle group 4 carried on the charging sleeve 3 and conveyed to the charging area upstream from the position of the vertical magnetic field 4 is magnetically released and falls to the photosensitive drum 1 side. The magnetic force of each of the magnet bodies is 800 to 1000 on the sleeve 3 in the fixed magnet body 2A.
The magnetic force of Gauss is set so that the first magnet body 5A can obtain a magnetic force of about 300 to 500 Gauss on the surface of the photosensitive drum 1. Further, by setting the magnetic force of the N-pole magnet body 5B to be substantially equal to that of the first magnet body 5A, a magnetic force of about 300 to 500 gauss can be obtained on the surface of the photosensitive drum 1, and the magnetic force of the repulsive magnet body 2B can be obtained. Is set so that a magnetic force of 800 to 1000 gauss can be obtained on the sleeve 3 at the position immediately above.
【００１８】この場合第１及びＮ極の磁石体５Ａ、５Ｂ
の感光体表面磁力は均一帯電と密着性の向上の為に出来
る限り大きくしたほうがよいが、垂直磁場４Ａ上で感光
体ドラム１側から帯電スリーブ３側への粒子の移動を円
滑にするために、感光体ドラム１側よりスリーブ３側の
磁力を強くする必要がある。In this case, the first and N-pole magnet bodies 5A, 5B
It is preferable to increase the surface magnetic force of the photosensitive member as much as possible to improve uniform charging and adhesion, but in order to smoothly move particles from the photosensitive drum 1 to the charging sleeve 3 on the vertical magnetic field 4A. Therefore, it is necessary to make the magnetic force on the sleeve 3 side stronger than that on the photosensitive drum 1 side.
【００１９】かかる実施例によれば、前記感光体ドラム
１上の水平磁場上で磁性粒子群４を密着させながら感光
体ドラム１表面を円滑に帯電させた微粒子群４は、感光
体ドラム１の回転に従って垂直磁場位置まで移動し、こ
こで該垂直磁場により微粒子群４Ａが磁気的に封止さ
れ、帯電領域外への漏洩を阻止すると共に、磁力差によ
り、感光体ドラム１側よりスリーブ３側へ向け磁性粒子
群が吸着され、そして帯電スリーブ３のアゲインスト回
転により該スリーブ３に担持されたまま帯電領域上流側
に移動する。ここで反発磁石体２Ｂとの間の反発磁界に
よる無磁力帯上に磁性粒子群４が達すると、前記帯電ス
リーブ３に担持されて磁性粒子群４が磁気的に開放さ
れ、感光体ドラム１側に落下し、以下前記動作を繰り返
す。According to this embodiment, the fine particle group 4 having the surface of the photosensitive drum 1 smoothly charged while keeping the magnetic particle group 4 in close contact with the horizontal magnetic field on the photosensitive drum 1 The particles move to the position of the vertical magnetic field according to the rotation, where the vertical magnetic field magnetically seals the fine particle group 4A to prevent the particles from leaking out of the charged area. The magnetic particles are adsorbed toward the surface of the charging sleeve 3, and move toward the upstream side of the charging area while being carried by the sleeve 3 by the against rotation of the charging sleeve 3. Here, when the magnetic particle group 4 reaches the non-magnetic force zone due to the repulsive magnetic field between the magnetic particle group and the repulsive magnet body 2B, the magnetic particle group 4 is carried on the charging sleeve 3 and is magnetically released, and the photosensitive drum 1 side And the above operation is repeated.
【００２０】そしてかかる帯電装置の軸端側では図１に
示すようなレイアウト構成を取るのがよい。即ち（Ａ）
は斜視図、（Ｂ）はその平面図で、現像領域下流端より
僅かに感光体ドラム１移動方向下流側の帯電スリーブと
感光体ドラム間の空域に前記固定磁石体２Ａ及び第１の
磁石体５Ａと対向する位置に先端を楔状に形成した略台
形状の第２の磁石体５ＣをＳ極を第１の磁石体５Ａ側に
対向させて配設する。即ち前記台形状の第２の磁石体５
Ｃは、磁性粒子４が接触している部分（帯電領域１０
Ａ）と、磁性粒子４が接触していない部分（非帯電領域
１０Ｂ）との間の境界線上を跨がって配置されており、
そして第２の磁石体５Ｃの磁力密度は前記第１の磁石体
５Ａの感光体ドラム１表面上における磁力密度より大で
且つ固定磁石体２Ａではスリーブ３上での磁力密度より
小になるように、例えば６００〜７００ガウス程度に設
定する。さて前記固定磁石体２Ａと第１及びＮ極の磁石
体５Ａ、５Ｂの軸端は同一垂直線上に沿って垂直に切断
されており、そして前記帯電スリーブ３を介して１５０
Ｖ前後の直流帯電電位が印加される。そして感光体ドラ
ム１軸端側の帯電電位は、図６に示すように磁性粒子４
が接触している部分（帯電領域１０Ａ）では前記帯電電
位に相当するＶ0の電位が印加され、又磁性粒子４が接
触していない部分（非帯電領域１０Ｂ）では０Ｖの電位
となる。従ってこの状態で感光体ドラム１を矢印方向に
回転させると帯電領域１０Ａと非帯電領域１０Ｂの境界
線で前記（Ｖ0−０）の電位差により感光体ドラム１の
回転に従って粒子引きが生じてしまうが、その下流端に
おいて第２の磁石体５Ｃの反発磁界が形成されているた
めに、帯電領域下流側に搬送されることなく、固定磁石
体２Ａと第１の磁石体５Ａとにより形成される垂直磁場
６Ｂにより垂直方向に逃げる。It is preferable to adopt a layout configuration as shown in FIG. 1 on the shaft end side of such a charging device. That is, (A)
3B is a perspective view, and FIG. 3B is a plan view of the fixed magnet body 2A and the first magnet body in an empty space between the charging sleeve and the photosensitive drum slightly downstream in the moving direction of the photosensitive drum 1 from the downstream end of the developing area. A substantially trapezoidal second magnet body 5C whose tip is formed in a wedge shape is provided at a position facing the first magnet body 5A at a position facing the first magnet body 5A. That is, the trapezoidal second magnet body 5
C is the portion where the magnetic particles 4 are in contact (the charged area 10
A) and a portion where the magnetic particles 4 are not in contact (uncharged region 10B), and are arranged so as to extend over the boundary line.
The magnetic density of the second magnet 5C is larger than the magnetic density of the first magnet 5A on the surface of the photosensitive drum 1 and smaller than the magnetic density of the fixed magnet 2A on the sleeve 3. For example, it is set to about 600 to 700 Gauss. The shaft ends of the fixed magnet body 2A and the first and N-pole magnet bodies 5A and 5B are cut vertically along the same vertical line, and
A DC charging potential of around V is applied. As shown in FIG. 6, the electric potential of the photosensitive drum 1 at the axial end is changed to the magnetic particles 4
Is applied to the portion where the magnetic particles 4 are in contact (charged region 10A), and the potential is 0 V in the portion where the magnetic particles 4 are not in contact (the non-charged region 10B). Therefore, if the photosensitive drum 1 is rotated in the direction of the arrow in this state, particles are drawn according to the rotation of the photosensitive drum 1 due to the potential difference (V 0 −0) at the boundary between the charged region 10A and the non-charged region 10B. Is formed by the fixed magnet body 2A and the first magnet body 5A without being conveyed to the downstream side of the charging area because the repulsive magnetic field of the second magnet body 5C is formed at the downstream end. Escape in the vertical direction due to the vertical magnetic field 6B.
【００２１】そして垂直方向に向った磁性粒子群４は、
今度は逆に第２の磁石体５Ｃと固定磁石体２Ａとの吸引
力によりスリーブ３側に付着し、その後スリーブ３の回
転に従って帯電領域上流側の水平磁場６Ａ側に引戻さ
れ、以下繰り返し循環を行なう。The magnetic particle group 4 oriented in the vertical direction is
This time, on the contrary, it adheres to the sleeve 3 side by the attraction force of the second magnet body 5C and the fixed magnet body 2A, and then is returned to the horizontal magnetic field 6A side on the upstream side of the charging area according to the rotation of the sleeve 3; Perform
【００２２】従ってかかる実施例によれば帯電領域下流
側に磁性粒子４が漏洩することなく円滑な帯電が行なわ
れる。Therefore, according to this embodiment, the smooth charging is performed without the magnetic particles 4 leaking to the downstream side of the charging area.
【００２３】尚、前記第２の磁石体５Ｃは両軸端側にの
み配設することなく、図１（Ａ）（Ｂ）の想像線に示す
ように、第１の磁石体の軸方向全域に亙って第２の磁石
体５Ｃ’配設することにより、軸方向全域に亙って帯電
領域下流側に磁性粒子４が漏洩することが阻止される。
さて前記実施例のように磁石体５Ｃを用いて磁性粒子の
帯電領域の保持を行う構成では、その軸端側で図３
（Ａ）に示すように軸方向に広がった磁力線が形成され
てしまい、結果として該磁力線に沿って粒子群のはみ出
しが大きくなってしまう。そこで、このような場合は、
図３（Ｂ）及び図２（Ａ）に示すように隣接する逆極性
の磁石体５Ａ、２Ａ、の内、１の磁石体、本実施例にお
いては固定磁石体２Ａの磁石端に薄板状の磁性体５１を
張り付けて磁気的閉回路を構成してエッジ効果をもたせ
ることにより、前記欠点の解消と共に、前記第１の磁石
体５Ａ軸端よりのはみ出しを少なくする事が出来る。又
図２（Ｂ）に示すように、隣接する第１及びＮ極の磁石
体５Ａ、５Ｂの内、Ｎ極の磁石体５Ｂの磁石端に薄板状
の磁性体５１を張り付けて磁気的閉回路を構成してエッ
ジ効果をもたせることにより、軸端よりのはみ出しを少
なくする事が出来る。更に図２（Ｃ）に示すように、前
記第１の磁石体５Ａ及びＮ極の磁石体５Ｂの軸端側に反
発磁極５２を対面させても同様な効果をえることが出来
る。即ち前記の理由を具体的に説明すると前記の様に粒
子引きの原因は前記したように、 帯電領域１０Ａと非
帯電領域１０Ｂの境界線で前記（Ｖ0−０）の電位差が
存在する事にある。従って前記電位差を小さくするとと
もに、前記磁性体５１若しくは反発磁極５２で軸端側へ
の広がりを押え、前記第１の磁石体２Ａ及び５Ａの軸端
間で磁気的閉回路等を形成することにより粒子引きを阻
止することが出来るものである。Incidentally, the second magnet body 5C is not disposed only on both ends of the shaft, but as shown by the imaginary lines in FIGS. 1A and 1B, the entire area of the first magnet body in the axial direction. The magnetic particles 4 are prevented from leaking to the downstream side of the charged region over the entire region in the axial direction by disposing the second magnet body 5C ′ over the entire length of the magnetic body.
In the configuration in which the charged area of the magnetic particles is held by using the magnet body 5C as in the above-described embodiment, the shaft end side of FIG.
As shown in (A), the lines of magnetic force that spread in the axial direction are formed, and as a result, the protrusion of the particles along the lines of magnetic force increases. So, in such a case,
As shown in FIGS. 3 (B) and 2 (A), one of the adjacent magnet bodies 5A, 2A of opposite polarity has a thin plate shape on the magnet end of the fixed magnet body 2A in this embodiment. By attaching the magnetic body 51 to form a magnetically closed circuit to provide an edge effect, the above-described disadvantage can be eliminated and the protrusion from the shaft end of the first magnet body 5A can be reduced. As shown in FIG. 2 (B), a thin plate-shaped magnetic body 51 is attached to the magnet end of the N-pole magnet body 5B of the adjacent first and N-pole magnet bodies 5A and 5B, and a magnetic closed circuit is formed. And by providing the edge effect, the protrusion from the shaft end can be reduced. Further, as shown in FIG. 2 (C), the same effect can be obtained even if the repulsion magnetic pole 52 faces the shaft end side of the first magnet body 5A and the N-pole magnet body 5B. That is, the reason for the above will be specifically described. As described above, the cause of the particle pulling is that the potential difference (V 0 −0) exists at the boundary between the charged region 10A and the non-charged region 10B. is there. Therefore, the potential difference is reduced, and the magnetic body 51 or the repulsive magnetic pole 52 suppresses the spread toward the shaft end, thereby forming a magnetically closed circuit or the like between the shaft ends of the first magnet bodies 2A and 5A. Particle pulling can be prevented.
【００２４】[0024]
【効果】以上記載のごとく本発明によれば帯電領域の軸
端側において磁性体若しくは磁石体を効果的に配するこ
とで、帯電領域軸端側における粒子引きを有効に阻止し
得る。等の種々の著効を有す。As described above, according to the present invention, by effectively disposing the magnetic material or the magnet body on the axial end side of the charged area, it is possible to effectively prevent the particles from being attracted on the axial end side of the charged area. And so on.
【図１】本発明の第１実施例にかかる帯電装置の軸端側
の概略図で、（Ａ）は斜視図、（Ｂ）は要部平面図であ
る。FIG. 1 is a schematic view of a shaft end side of a charging device according to a first embodiment of the present invention, where (A) is a perspective view and (B) is a plan view of a main part.
【図２】本発明の第２実施例の帯電装置の概略図で、
（Ａ）は固定磁石体に磁性体を貼着した場合の感光体ド
ラムと帯電スリーブ間の磁性粒子分布の状態を、（Ｂ）
は感光体ドラム背面側の一対の磁石体の内１の磁石体に
磁性体を貼着した場合の磁性粒子分布の状態を、（Ｃ）
は感光体ドラム背面側の一対の磁石体に反発磁極を対面
させた場合の磁性粒子分布の状態を、夫々示す。FIG. 2 is a schematic view of a charging device according to a second embodiment of the present invention;
(A) shows the state of the magnetic particle distribution between the photosensitive drum and the charging sleeve when the magnetic body is attached to the fixed magnet body, and (B)
(C) shows the state of the magnetic particle distribution when the magnetic substance is attached to one of the pair of magnet bodies on the back side of the photosensitive drum.
Indicates the state of the magnetic particle distribution when the repulsive magnetic pole faces the pair of magnets on the back side of the photosensitive drum.
【図３】（Ａ）は従来技術の固定磁石体の磁力線分布の
状態を、（Ｂ）は固定磁石体に磁性体を貼着した場合の
固定磁石体の磁力線分布の状態を示す。FIG. 3A shows a state of a magnetic field distribution of a conventional fixed magnet body, and FIG. 3B shows a state of a magnetic field line distribution of the fixed magnet body when a magnetic body is attached to the fixed magnet body.
【図４】（Ａ）は本発明の実施例にかかる帯電装置の全
体概略図、（Ｂ）は要部拡大図である。FIG. 4A is an overall schematic diagram of a charging device according to an embodiment of the present invention, and FIG. 4B is an enlarged view of a main part.
【図５】従来技術にかかる帯電装置の全体概略図であ
る。FIG. 5 is an overall schematic diagram of a charging device according to the related art.
【図６】図１の帯電電位の状態を示すグラフ図である。FIG. 6 is a graph showing a state of a charged potential in FIG. 1;
１ 感光体 ２Ａ 固定磁石体 ３ 帯電スリーブ ４ 磁性粒子群 ５Ａ 第１の磁石体 ５Ｃ 第２の磁石体 ５１ 磁性体 ５２ 反発磁極 DESCRIPTION OF SYMBOLS 1 Photoconductor 2A Fixed magnet body 3 Charging sleeve 4 Magnetic particle group 5A First magnet body 5C Second magnet body 51 Magnetic body 52 Repulsive magnetic pole
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平５−181347（ＪＰ，Ａ) 特開 昭54−143652（ＪＰ，Ａ) 特開 昭55−65977（ＪＰ，Ａ) 実開 平２−87248（ＪＰ，Ｕ) 実公 昭42−6222（ＪＰ，Ｙ１) (58)調査した分野(Int.Cl.7，ＤＢ名) G03G 15/02 G03G 15/08 - 15/095 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-181347 (JP, A) JP-A-54-143652 (JP, A) JP-A-55-65977 (JP, A) 87248 (JP, U) Jikken 42-6222 (JP, Y1) (58) Fields investigated (Int. Cl. 7 , DB name) G03G 15/02 G03G 15/08-15/095
Claims (9)
置し、該磁石体若しくは他の磁石体との協動作用で感光
体表面の帯電領域上に保持された磁性粒子群を介して感
光体を帯電可能に構成した感光体の帯電装置において、 感光体ドラムの帯電領域内に対向させて、非磁性の帯電
スリーブの背面側に固定磁石体を固定配置するととも
に、これと逆極性である感光体帯電領域下流側の感光体
背面側に位置する磁石体（以下第１の磁石体という）の
少なくとも感光体軸端側の、前記感光ドラムと帯電スリ
ーブ間に形成される空間上に前記第１の磁石体と同極性
の第２の磁石体を配設し、該第２の磁石体が前記帯電ス
リーブを挟んで固定磁石体と、及び感光体を挟んで第１
の磁石体と夫々ほぼ対向するごとく配置した事を特徴と
する帯電装置。At least one magnet body is disposed on the back side of a photoreceptor, and a group of magnetic particles held on a charged area on the surface of the photoreceptor for cooperating with the magnet body or another magnet body is provided. In the photoreceptor charging device, the photoreceptor is configured to be able to be charged by charging the photoreceptor. At least on a space formed between the photosensitive drum and the charging sleeve, at least on the photosensitive member shaft end side of a magnet member (hereinafter, referred to as a first magnet member) located on the photosensitive member rear side downstream of the photosensitive member charging area. A second magnet body having the same polarity as the first magnet body is provided, and the second magnet body has a fixed magnet body with the charging sleeve interposed therebetween, and a first magnet body with the photoconductor interposed therebetween.
A charging device, wherein the charging device is disposed so as to substantially face each of the magnet bodies.
が逆方向である請求項１記載の感光体の帯電装置におい
て、前記第２の磁石体が帯電ローラ回転方向の帯電位置
下流側の感光体ドラム表面上空間に配置されている事を
特徴とする請求項１記載の帯電装置。2. The photoconductor charging device according to claim 1, wherein the rotation direction of the photoconductor drum and the charging sleeve is opposite to each other, wherein the second magnet body is located downstream of the charging position in the rotation direction of the charging roller. The charging device according to claim 1, wherein the charging device is disposed in a space above the surface of the drum.
電領域とその外側の非帯電領域との間の境界線上を跨が
って配置されていることを特徴とする請求項１記載の帯
電装置。3. The image forming apparatus according to claim 2, wherein the second magnet body is disposed so as to extend over a boundary between a charged region on the photosensitive member shaft end side and a non-charged region outside the charged region. 2. The charging device according to 1.
置する非磁性の帯電スリーブ内に配置されている請求項
３記載の帯電装置において 前記第２の磁石体の磁力密度は前記第１の磁石体の感光
体ドラム１表面上における磁力密度より大で且つ固定磁
石体では帯電スリーブ上での磁力密度より小になるよう
に構成した事を特徴とする請求項３記載の帯電装置。4. The charging device according to claim 3, wherein the fixed magnet body is disposed in a non-magnetic charging sleeve located on a photosensitive body charging area. The magnetic force density of the second magnet body is the first magnetic body. 4. The charging device according to claim 3, wherein the magnetic body is configured to have a magnetic force density larger than the magnetic force density on the surface of the photosensitive drum 1 and to be smaller than the magnetic force density of the fixed magnet body on the charging sleeve.
電領域とその外側の非帯電領域との間の境界線上を跨が
って配置させ、更にその軸端が第１の磁石体の外端面よ
り僅かに外方に位置するまで感光体軸方向全域に亙って
延在させることを特徴とする請求項１記載の帯電装置。5. The image forming apparatus according to claim 1, wherein the second magnet body is disposed so as to straddle a boundary between a charged area on the photoconductor axis end side and a non-charged area outside the photoconductor axis end. 2. The charging device according to claim 1, wherein the magnet extends over the entire area in the axial direction of the photoconductor until it is located slightly outside the outer end surface of the magnet.
帯電領域上流側の感光体背面側に、第１の磁石体と逆極
性の磁石体を配設し、前記２つの磁石体により感光体の
電領域に水平磁場を形成した事を特徴とする請求項１記
載の帯電装置。6. A magnet body having a polarity opposite to that of the first magnet body is provided adjacent to the first magnet body and on the back side of the photosensitive body upstream of the photosensitive body charging area, and the two magnet bodies are provided. 2. The charging device according to claim 1, wherein a horizontal magnetic field is formed in an electric region of the photoconductor by the method.
帯電領域上流側の感光体背面側に、第１の磁石体と逆極
性の磁石体を配設し、前記２つの磁石体により感光体の
電領域に水平磁場を形成するとともに、前記２つの磁石
体の軸端と対面させて、夫々の磁石体と同極性の反発磁
極を形成したことを特徴とする請求項１記載の帯電装
置。7. A magnet body having a polarity opposite to that of the first magnet body is provided adjacent to the first magnet body and on the back side of the photosensitive body upstream of the photosensitive body charging area, and the two magnet bodies are provided. 2. A horizontal magnetic field is formed in an electric field of the photoconductor by means of a magnetic field, and a repulsion magnetic pole having the same polarity as each of the magnets is formed to face the axial ends of the two magnets. Charging device.
帯電領域上流側の感光体背面側に、第１の磁石体と逆極
性の磁石体を配設し、前記２つの磁石体により感光体の
電領域に水平磁場を形成するとともに、前記２つの磁石
体の内、少なくとも１つの磁石体の軸端面に磁性体を配
設し、磁気的エッジ効果をもたせるとともに、前記磁性
粒子群に印加する帯電バイアスを４００Ｖ以下に設定し
た事を特徴とする請求項１記載の帯電装置。8. A magnet body having a polarity opposite to that of the first magnet body is provided adjacent to the first magnet body and on the back side of the photosensitive body upstream of the photosensitive body charging area. Forming a horizontal magnetic field in the electric region of the photoconductor, and arranging a magnetic body on an axial end face of at least one of the two magnet bodies to have a magnetic edge effect and to form the magnetic particle group. 2. The charging device according to claim 1, wherein the charging bias applied to the charging device is set to 400 V or less.
帯電領域上流側の感光体背面側に、第１の磁石体と逆極
性の磁石体を配設し、前記２つの磁石体により感光体の
電領域に水平磁場を形成するとともに、前記２つの磁石
体の内少なくとも一の磁石体の軸端面と対面させて反発
磁極を設けるとともに、前記前記磁性粒子群に印加する
帯電バイアスを４００Ｖ以下に設定した事を特徴とする
請求項１記載の帯電装置。9. A magnet body having a polarity opposite to that of the first magnet body is provided adjacent to the first magnet body and on the back side of the photosensitive body upstream of the photosensitive body charging area, and the two magnet bodies are provided. A horizontal magnetic field is formed in the electric field of the photoreceptor, and a repulsion magnetic pole is provided facing the axial end face of at least one of the two magnet bodies, and a charging bias applied to the magnetic particle group is provided. 2. The charging device according to claim 1, wherein the voltage is set to 400 V or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23902693A JP3281139B2 (en) | 1993-08-31 | 1993-08-31 | Charging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23902693A JP3281139B2 (en) | 1993-08-31 | 1993-08-31 | Charging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0772714A JPH0772714A (en) | 1995-03-17 |
| JP3281139B2 true JP3281139B2 (en) | 2002-05-13 |
Family
ID=17038785
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23902693A Expired - Fee Related JP3281139B2 (en) | 1993-08-31 | 1993-08-31 | Charging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3281139B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6781613B2 (en) * | 2001-08-10 | 2004-08-24 | Ricoh Company, Ltd. | Electrification apparatus and image forming apparatus |
-
1993
- 1993-08-31 JP JP23902693A patent/JP3281139B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0772714A (en) | 1995-03-17 |
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