JP3399933B2 - Brush charging device - Google Patents
Brush charging deviceInfo
- Publication number
- JP3399933B2 JP3399933B2 JP2002019105A JP2002019105A JP3399933B2 JP 3399933 B2 JP3399933 B2 JP 3399933B2 JP 2002019105 A JP2002019105 A JP 2002019105A JP 2002019105 A JP2002019105 A JP 2002019105A JP 3399933 B2 JP3399933 B2 JP 3399933B2
- Authority
- JP
- Japan
- Prior art keywords
- brush
- charged
- bristles
- curvature
- support
- 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
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、例えば電子写真装
置等に係るブラシ帯電装置に関する。The present invention relates to, for example about the brush band electrical location of the electrophotographic apparatus.
【０００２】[0002]
【従来の技術】従来、電子写真の帯電装置としては、ス
コロトロンを用いたコロナ放電器が主流であった。しか
しコロナ帯電は放電現象を利用するため、特にマイナス
帯電では人体に有害なオゾンを多量に発生する。また、
印加電圧が−４〜−５ｋｖと比較的高く、電流もほとん
どがケ−スに流れてしまうため、エネルギーロスが大き
いという欠点があった。近年ではコロナ帯電にかわり、
オゾンがほとんど発生しない接触帯電技術が進歩してい
る。その代表的なものが導電性ローラを用いたローラ帯
電方式とブラシ帯電方式である。両者とも、オゾン発生
量はコロナ帯電器の１００分の１以下であると言われ、
また印加電圧も−１ｋｖ程度と比較的低く、電流もケー
スに流れることがないのでロスも少ない。2. Description of the Related Art Conventionally, as a charging device for electrophotography, a corona discharger using a scorotron has been the mainstream. However, since corona charging utilizes a discharging phenomenon, a large amount of ozone, which is harmful to the human body, is generated particularly when negatively charging. Also,
The applied voltage was relatively high at -4 to -5 kv, and most of the current also flowed into the case, resulting in a large energy loss. In recent years, instead of corona charging,
Contact charging technology, in which ozone is hardly generated, has advanced. Typical examples are a roller charging method using a conductive roller and a brush charging method. Both of them are said to generate ozone less than 1/100 that of corona chargers.
In addition, the applied voltage is relatively low at about -1 kv, and no current flows to the case, so there is little loss.
【０００３】[0003]
【発明が解決しようとする課題】しかし、ロ−ラ帯電方
式は、トナーや紙粉などのゴミに弱く、それがすぐに帯
電むらとなって画像に現れてしまう。また導電性ローラ
自体の値段を考えてもコスト的に不利である。一方ブラ
シ帯電器は、ローラよりはトナーや紙粉などの汚れに強
く、また値段も安いことから小型で安価な装置において
有効な帯電手段である。しかし、ブラシ帯電器はその形
状故、複写械、プリンタなど、特に反転現像方式を用い
た電子写真プロセスにおいてハーフトーンを印字する
と、被帯電体の面移動方向にそって、白筋が多数発生し
てしまう。マイナス帯電の反転現像方式において白筋に
なるのは、被帯電体の表面電位が局部的にマイナス側に
高くなっていることを意味している。これはブラシ特有
の帯電むらで、固定型の導電性ブラシでは特に顕著であ
る。固定型のブラシは、基盤に導電性の接触子を植毛し
たもので、金属細線や導電性繊維が知られているが、後
者の方が一般的で、柔軟なレーヨンやナイロンにカーボ
ンを分散させた繊維が主流である。そしてそのブラシ表
面は、一般に平面状のものが多い。一方それに接触する
被帯電体面は、ドラムを使用する場合は曲率をもった面
となる。すなわち平面状のブラシを曲率を持った被帯電
体面に当接させることで、ブラシ毛が均一に被帯電体面
に当接せず、それが異常な帯電状態をつくりだし、電位
が局部的にマイナス側に高くなって筋を増やす要因にな
っているのである。そして、その問題を解決するために
は、ブラシ自体に被帯電体とほぼ同じ曲率を与えて、毛
先が被帯電体表面に均一に当接するようにすればよい
が、製造上難しく生産コストを考慮すると量産に適した
方法が知られていない。However, the roller charging method is vulnerable to dust such as toner and paper dust, and it immediately appears in the image as uneven charge. Further, considering the price of the conductive roller itself, it is disadvantageous in terms of cost. On the other hand, the brush charger is more effective than a roller against dirt such as toner and paper dust, and is cheap in price. Therefore, the brush charger is an effective charging means in a small and inexpensive device. However, because of the shape of the brush charger, many half-streaks are generated along the surface movement direction of the body to be charged when printing halftones in copying machines, printers, etc., especially in the electrophotographic process using the reversal development method. Will end up. The white streak in the negative charging reversal development method means that the surface potential of the body to be charged locally becomes higher on the negative side. This is a charging unevenness peculiar to the brush, and is particularly remarkable in the fixed conductive brush. Fixed brushes are made by implanting conductive contacts on the base.Metal fine wires and conductive fibers are known, but the latter is more common, with carbon dispersed in flexible rayon or nylon. Fibers are the mainstream. The surface of the brush is generally flat. On the other hand, the surface of the body to be charged in contact with it becomes a surface having a curvature when a drum is used. That is, by bringing a flat brush into contact with the surface of the charged body having a curvature, the brush bristles do not uniformly contact the surface of the charged body, which creates an abnormal charged state, and the potential is locally on the negative side. It is becoming a factor to increase the muscle. Then, in order to solve the problem, it is sufficient to give the brush itself substantially the same curvature as the charged body so that the tips of the brushes uniformly contact the surface of the charged body, but this is difficult to manufacture and the production cost is reduced. Considering it, there is no known method suitable for mass production.
【０００４】本発明は、このような課題を解決するため
のもので、簡単にブラシ帯電器特有のハーフトーンの白
筋の発生を減少させることのできるブラシ帯電装置を提
供するものである。[0004] The present invention is intended to solve such problems, simply Hisage <br/> subjected brush band electrical location that can reduce the occurrence of brush charger white muscle specific halftone It is a thing.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
に、本発明のブラシ帯電装置は、バイアス電圧を印加し
た固定型のブラシを被帯電体の表面に当接させて帯電を
行うブラシ帯電装置であり、さらに、前記ブラシが植毛
されたブラシ支持面を有するブラシ支持体を備えている
とともに、前記ブラシの毛先が前記被帯電体の表面に当
接するように前記ブラシ支持体が配置され、且つ前記被
帯電体の回転によりこの被帯電体の表面が前記回転の方
向へ移動するとともに、前記被帯電体の表面の前記ブラ
シとの当接部位が前記ブラシ側に膨出しその当接部位が
曲率を有するブラシ帯電装置において、上記ブラシの毛
先が前記被帯電体の表面の移動方向に対して順方向にな
びくように、前記ブラシの毛に斜毛処理を施し、この斜
毛処理を前記被帯電体の回転の軸方向からみた断面で考
えた場合、前記ブラシ支持面と前記ブラシの毛とがなす
鋭角の値をθ1、前記被帯電体の表面の前記ブラシとの
当接部位の曲率半径をａ、前記ブラシの毛の長さをｂ、
前記曲率半径の曲率中心より前記ブラシ支持体のブラシ
支持面に引いた垂線の該ブラシ支持面との交点から、前
記被帯電体の表面の移動方向を基準とした場合の最上流
側の前記ブラシの毛の基端を支持する前記ブラシ支持面
上の点までの距離をｃとしたとき、ｃｏｓθ1＞ｃ／
（ａ＋ｂ）を満たすように設定したものである。In order to achieve the above object, the brush charging device of the present invention charges a fixed brush to which a bias voltage is applied to the surface of a member to be charged.
It is a brush charging device, and further, the brush is flocked.
A brush support having a brush support surface
At the same time, the bristles of the brush contact the surface of the charged body.
The brush support is arranged so as to be in contact with the
Due to the rotation of the charged body, the surface of this charged body is
While moving in the direction of the
The contact portion with the bulge bulges toward the brush side and the contact portion
In a brush charging device having a curvature, as fluttering in the forward bristle tips of the brush to the moving direction of the surface of the member to be charged is subjected to Hasuke treatment the hair of the brush, the swash
Consider hair treatment with a cross section viewed from the axial direction of rotation of the charged body.
The brush support surface and the bristles of the brush form
The value of the acute angle is θ 1 , the surface of the charged body and the brush
The radius of curvature of the contact portion is a, the length of the bristles of the brush is b,
The brush of the brush support from the center of curvature of the radius of curvature
From the intersection of the perpendicular drawn to the supporting surface with the brush supporting surface,
The uppermost stream based on the moving direction of the surface of the charged body
Side brush supporting surface that supports the proximal end of the bristles of the brush
When the distance to the upper point is c, cos θ 1 > c /
It is set so as to satisfy (a + b).
【０００６】また、本発明のブラシ帯電装置は、バイア
ス電圧を印加した固定型のブラシを被帯電体の表面に当
接させて帯電を行うブラシ帯電装置であり、さらに、前
記ブラシが植毛された第１及び第２の支持面からなるブ
ラシ支持面を有するブラシ支持体を備え、前記第１及び
第２の支持面の境界部分を折曲部として前記ブラシ支持
体が前記被帯電体側に折曲されているとともに、前記ブ
ラシの毛先が前記被帯電体の表面に当接するように前記
ブラシ支持体が配置され、且つ前記被帯電体の回転によ
りこの被帯電体の表面が前記回転の方向へ移動するとと
もに、前記被帯電体の表面の前記ブラシとの当接部位が
前記ブラシ側に膨出しその当接部位が曲率を有するブラ
シ帯電装置において、前記ブラシを支持する前記ブラシ
支持体と前記被帯電体との配置関係を、前記被帯電体の
回転の軸方向からみた断面で考えた場合、前記被帯電体
の表面の前記ブラシとの当接部位の曲率半径をａ、前記
ブラシの毛の長さをｂ、前記被帯電体の表面の移動方向
を基準とした場合の最上流側の前記ブラシの毛の基端を
支持する前記ブラシ支持面上の点から、前記折曲部まで
の距離をｄ、前記被帯電体の表面の移動方向を基準とし
た場合の最上流側の前記ブラシの毛の基端を支持する前
記ブラシ支持面上の点と前記折曲部とを結ぶ線と、前記
曲率半径の曲率中心と前記折曲部とを結ぶ線と、がなす
鋭角の値をθ2としたとき、ｔａｎθ2＜（ａ＋ｂ）／ｄ
を満たすように設定したものである。Further, in the brush charging device of the present invention, a fixed brush to which a bias voltage is applied is applied to the surface of the member to be charged.
It is a brush charging device that charges by contacting it.
Brush consisting of first and second supporting surfaces on which brushes are implanted
A brush support having a brush support surface, the first and
The brush support with the boundary portion of the second support surface as a bent portion
The body is bent toward the charged body, and
Make sure that the hair tips of the brush touch the surface of the charged body.
A brush support is arranged, and rotation of the charged body causes
When the surface of the charged object of Riko moves in the direction of rotation,
Mostly, the contact portion of the surface of the charged body with the brush is
A bra that bulges toward the brush side and has a contact portion with a curvature
In the charging device, the brush that supports the brush
The positional relationship between the support and the body to be charged is determined by
Considering the section viewed from the axial direction of rotation, the charged body
A curvature radius of the contact portion between the brush surface, the
The length of the bristles of the brush is b, and the moving direction of the surface of the charged body
The base end of the bristles of the brush on the most upstream side when
From the point on the brush support surface that supports to the bent portion
The distance is d, and the moving direction of the surface of the body to be charged is a reference
Before supporting the base end of the bristles of the brush on the most upstream side when
A line connecting a point on the brush support surface and the bent portion,
A line connecting the center of curvature of the radius of curvature and the bent portion is formed.
When the acute angle value is θ 2 , tan θ 2 <(a + b) / d
It is set to satisfy.
【０００７】[0007]
【０００８】[0008]
【０００９】[0009]
【作用】したがって、本発明によれば、画像形成装置特
有の帯電むらによる白筋の発生を減少させることが可能
となる。Therefore, according to the present invention, it is possible to reduce the occurrence of white streaks due to the uneven charging characteristic of the image forming apparatus.
【００１０】[0010]
【発明の実施の形態】以下、この発明の実施の形態を図
面に基づいて説明する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.
【００１１】図１（ａ）は、ブラシの製造過程におい
て、ブラシの毛先をカットする方法である。ブラシの毛
の材質はレーヨンにカーボンを分散させたものやナイロ
ンなどがあげられ、それら繊維は導電性の基布に縫い付
けられた状態になったところで、仕上げ工程として、ブ
ラシ表面のカットを行う。そこで、導電性の繊維１を植
毛された基布２は、基布側の面から、ブラシ帯電器が被
帯電体表面に当接する部分での被帯電体表面とほぼ同じ
曲率を持った部材３にセットされる。そして図１（ｂ）
のように、カッター４で水平に毛先をカットすることに
より、導電性繊維１はそれぞれ所定の長さにカットされ
る。その後、ブラシを曲率部材３から取り外し、基布を
もとの水平な状態に戻すと、図１（ｃ）のようにブラシ
毛は取り付けてあった曲率部材とは反対方向の曲率にカ
ットされる。すなわち、きわめて簡単な方法で、被帯電
体とほぼ同曲率のブラシ面のカットがおこなえるわけで
ある。また、このときに得られる導電性繊維の先端面の
曲率は、支持部材３の曲率よりも繊維の長さ分だけ大き
くなるので、支持部材の曲率を、被帯電体曲率よりも若
干小さく設定してやることで、さらに被帯電体に近い曲
率の導電性繊維面をつくることができる。FIG. 1 (a) shows a method of cutting the tips of the brushes in the process of manufacturing the brush. Examples of the material of the brush bristles include those in which carbon is dispersed in rayon and nylon, and when those fibers are sewn to the conductive base fabric, the brush surface is cut as a finishing process. . Therefore, the base cloth 2 on which the conductive fibers 1 are implanted has a member 3 having substantially the same curvature as the surface of the charged body at the portion where the brush charger contacts the surface of the charged body from the surface of the base cloth side. Is set to. And FIG. 1 (b)
As described above, by horizontally cutting the hair tips with the cutter 4, the conductive fibers 1 are each cut into a predetermined length. After that, when the brush is removed from the curvature member 3 and the base cloth is returned to the original horizontal state, the brush bristles are cut into a curvature in the opposite direction to the attached curvature member as shown in FIG. 1 (c). . That is, it is possible to cut the brush surface having substantially the same curvature as that of the body to be charged by an extremely simple method. Further, since the curvature of the tip end surface of the conductive fiber obtained at this time is larger than the curvature of the support member 3 by the length of the fiber, the curvature of the support member is set to be slightly smaller than the charged body curvature. By doing so, it is possible to form a conductive fiber surface having a curvature closer to that of the charged body.
【００１２】また、ブラシ製造方法におけるブラシ毛の
カット工程では、多くの場合、図２（ａ）のように金属
などでできたドラム５に、支持部材３を設けその上に繊
維１を植毛済みの基布２を取付け、ドラム５を回転させ
ることで、ドラム５の外側に設置されたカッター４によ
り導電性繊維をカットし、ほぼ平坦なブラシ面を得てい
た。しかし、この方法では、ブラシカット面は、厳密に
は凸型になってしまい、これではブラシの毛先が被帯電
体表面に対して均一に当接することは望めない。そこ
で、毛先のカット工程において、図２（ｂ）に示すよう
に、繊維１を植毛済みの基布２を支持部材３を両側に設
けたドラム５の内側に取付け、ドラム５を回転させ、ド
ラム５の内側に設置したカッター４により毛先をカット
することにより、導電性繊維面を凹型にする。またさら
にここで、繊維１を植毛済みの基布２を取り付ける支持
部材３をドラム５とは反対の曲率にすることで、導電性
繊維面の曲率を大きくすることができ、被帯電体表面と
ほぼ同曲率のブラシ面を得ることが可能となる。同様に
図２（ａ）においても、支持部材３の曲率を大きくする
ことで同じ効果が得られる。また円筒形ドラムではなく
ガターを回転させることでも同様な効果が得られること
は言うまでもない。In the brush bristle cutting step in the brush manufacturing method, in many cases, the supporting member 3 is provided on the drum 5 made of metal as shown in FIG. The base fabric 2 was attached and the drum 5 was rotated to cut the conductive fibers by the cutter 4 installed outside the drum 5, thereby obtaining a substantially flat brush surface. However, in this method, the brush cut surface is strictly a convex shape, and thus it is not possible to evenly contact the bristle tips of the brush with the surface of the body to be charged. Therefore, in the step of cutting the hair tips, as shown in FIG. 2B, the base cloth 2 on which the fibers 1 have been planted is attached to the inside of the drum 5 provided with the support members 3 on both sides, and the drum 5 is rotated. The tip of the hair is cut by the cutter 4 installed inside the drum 5 to make the conductive fiber surface concave. Furthermore, here, the curvature of the conductive fiber surface can be increased by making the support member 3 to which the base fabric 2 on which the fibers 1 have been transplanted attached have a curvature opposite to that of the drum 5. It is possible to obtain brush surfaces having almost the same curvature. Similarly, also in FIG. 2A, the same effect can be obtained by increasing the curvature of the support member 3. It goes without saying that the same effect can be obtained by rotating the gutter instead of the cylindrical drum.
【００１３】続いて、導電性繊維面を凹型にカットする
ことなく、同じような効果を得る方法について説明す
る。ブラシ帯電におけるハーフトーン画像での白筋の原
因のひとつに、被帯電体表面に対する繊維の毛先の当接
状態が大きく影響していることは既に述べた。これまで
の帯電ブラシは、図３（ａ）に示すように、導電性繊維
の表面が平面状になっていて、それを曲率を持った被帯
電体表面に所定の食い込み量をもって当接させると、図
３（ｂ）に示すように、導電性繊維１と被帯電体７との
接触域で、被帯電体の面移動方向の上流側の毛先が被帯
電体の回転に対して逆毛立った状態になってしまう。こ
の状態で、反転現像方式の電子写真プロセスを用いてハ
ーフトーンの画出しをおこなうと、白筋が多数発生し、
特にブラシ帯電器を被帯電体に当接したまま放置した後
に印字を行うと白筋が顕著である。白筋が発生するのは
おもに多湿環境（ＲＨ８５％）と、低湿環境（ＲＨ２０
％）で、多湿では連続的な白筋になり、低湿では短い鋭
い白筋となる。低温環境における白筋の発生を防ぐには
被帯電体へのブラシ繊維の食い込み量をできるだけ小さ
くすると効果がある。被帯電体表面と同じ曲率を持った
ブラシ帯電器は、食い込み量を接触幅全域において小さ
く安定させることができ、さらに見かけの繊維密度も上
昇するため、筋の減少に効果が得られる。またこの白筋
は、ブラシ帯電器を被帯電体表面に当接した後の最初の
数十枚の印字で特に顕著である。これは逆毛立った繊維
が被帯電体の回転により面移動方向の下流側になびこう
とするために生じると思われ、数百枚印字した後では目
立たなくなる。そこで、初期状態における逆毛立った状
態の繊維をなくすため、固定型導電性ブラシの繊維を、
毛先が被帯電体７の面移動方向に対して順方向に一様に
なびくように、予め斜毛処理した。斜毛角度は、図４
（ａ）に示すように、被帯電体７の面移動方向に対して
一番上流側の繊維が、被帯電体表面と当接するときに、
被帯電体７の面移動方向の下流側になびけばよい。すな
わち図４（ａ）において、基布とブラシ繊維とのなす角
をθ1、被帯電体の半径をａ、ブラシの毛の長さをｂ、
被帯電体の中心からブラシ面に引いた垂線とブラシ基布
との交点からブラシの被帯電体上流側の端部との距離、
いわゆる上流側のブラシの植毛幅をｃのしたとき、ｃｏ
ｓθ1＞ｃ／（ａ＋ｂ）のような関係を満たせばよい。
これによって図４（ｂ）に示すように、ブラシ毛は被帯
電体７の面移動方向の下流側に揃ってなびくことにな
り、逆毛立つ繊維は存在しなくなる。実験では、斜毛処
理をおこなわないブラシに比べ、放置後の低湿での白筋
が著しく減少することが確認できた。この斜毛処理の方
法であるが、図５（ａ）のように、円筒形の容器８と、
それよりも小さい径の円柱状の部材９の間に導電性繊維
１を植毛した基布２を挟み込み、両部材のうちのどちら
が、または両方を回転させることで可能である。また図
５（ｂ）に示すように、固定型導電性ブラシに斜毛する
上流側から徐々に板状の部材１０を押し当てることによ
っても可能である。Next, a method for obtaining the same effect without cutting the conductive fiber surface in a concave shape will be described. As described above, one of the causes of white streaks in the halftone image during brush charging is that the contact state of the tips of the fibers with respect to the surface of the charged body has a great influence. In the conventional charging brush, as shown in FIG. 3 (a), the surface of the conductive fiber is flat, and when it is brought into contact with the surface of the charged object having a curvature with a predetermined bite amount. As shown in FIG. 3 (b), in the contact area between the conductive fiber 1 and the body to be charged 7, the hair tips on the upstream side in the surface movement direction of the body to be charged are opposite to the rotation of the body to be charged. You will be standing. In this state, when halftone images are output using the electrophotographic process of the reversal development method, many white streaks occur,
White streaks are particularly noticeable when printing is performed after leaving the brush charger in contact with the member to be charged. White streak mainly occurs in a high humidity environment (RH85%) and a low humidity environment (RH20
%), High humidity results in continuous white streaks, and low humidity results in short sharp white streaks. In order to prevent the generation of white streaks in a low temperature environment, it is effective to minimize the amount of brush fibers that bite into the body to be charged. The brush charger having the same curvature as the surface of the body to be charged can stabilize the amount of bite to be small in the entire contact width and further increase the apparent fiber density, which is effective in reducing streaks. The white streaks are particularly noticeable on the first several tens of prints made after the brush charger is brought into contact with the surface of the member to be charged. This is considered to occur because the reversely fluffed fibers try to flow to the downstream side in the surface movement direction due to the rotation of the body to be charged, and become inconspicuous after printing several hundred sheets. Therefore, in order to eliminate the fibers in the state of reverse fluffing in the initial state, the fibers of the fixed conductive brush are
Inclination treatment was performed in advance so that the tips of the hairs were uniformly fluttered in the forward direction with respect to the surface moving direction of the charged body 7. The angle of slant is shown in Fig. 4.
As shown in (a), when the fiber on the most upstream side with respect to the surface moving direction of the charged body 7 contacts the surface of the charged body,
It only has to flow to the downstream side in the surface movement direction of the charged body 7. That is, in FIG. 4A, the angle formed by the base cloth and the brush fiber is θ 1 , the radius of the body to be charged is a, the length of the bristles of the brush is b,
The distance from the intersection of the vertical line drawn from the center of the charged body to the brush surface and the brush base cloth to the end of the brush on the upstream side of the charged body,
When the flock width of the so-called upstream brush is c, co
It suffices to satisfy the relationship such as sθ 1 > c / (a + b).
As a result, as shown in FIG. 4 (b), the brush bristles flow uniformly on the downstream side of the surface-to-be-charged body 7 in the direction of surface movement, and there is no reverse bristling fiber. In the experiment, it was confirmed that the white streaks in the low humidity after being left were remarkably reduced as compared with the brush not subjected to the bristling treatment. This slanted hair treatment method includes a cylindrical container 8 as shown in FIG.
It is possible by sandwiching the base cloth 2 in which the conductive fibers 1 are planted between the cylindrical members 9 having a diameter smaller than that, and rotating either or both of the members. Alternatively, as shown in FIG. 5B, it is also possible to gradually press the plate-shaped member 10 against the fixed conductive brush from the upstream side where the bristles are slanted.
【００１４】また、ブラシ繊維自体を斜毛処理や曲率カ
ットせずにすむ方法としては、次のようなものがあげら
れる。これは図６（ａ）に示すように、導電性繊維１の
植毛された基布２を、被帯電体表面の湾曲に沿うような
方向に１箇所以上に角度を持たせた支持部材６に取り付
けるということで、この方法によれば、製造上問題とな
る曲率にカットや、斜毛処理などを必要しない。Further, as a method of eliminating the bristles and curving of the brush fiber itself, there are the following methods. As shown in FIG. 6 (a), this is a support member 6 in which the base fabric 2 in which the conductive fibers 1 are implanted is angled at one or more locations in a direction along the curvature of the surface of the body to be charged. By mounting, according to this method, there is no need to perform cutting or beveling on the curvature which is a problem in manufacturing.
【００１５】図６（ａ）において、被帯電体７の半径を
ａとして、ブラシの繊維の長さをｂ、ブラシ支持部材の
角度θ2の頂点から、ブラシの被帯電体７の面移動方向
の上流側への幅をｄとしたとき、その一番端の毛先が、
被帯電体の面移動方向の下流側になびくように角度θ2
を設定する。すなわち、ｔａｎθ2＜（ａ＋ｂ）／ｄを
満たすようにθ2の値を規定することによって、ブラシ
の毛先が被帯電体表面に対して、逆毛立って当接するこ
とがない。これによってブラシの上流側で逆毛立って被
帯電体に当接する毛先がなくなり、低湿の初期状態にお
ける白筋が減少する。また、この方法によると、図６
（ｂ）に示したように、導電性繊維１と被帯電体との接
触域の上流側の部分の繊維の被帯電体に対する食い込み
量が密度が大きくなるため、少ない帯電幅で安定した帯
電が可能になる。そしてまた、このようなブラシ帯電器
は、電子写真装置において使用する場合には、図７に示
すようにプロセスカートリッジの一部分にあらかじめ角
度を設けておき、そこにブラシ帯電器を基布ごと取り付
けることで簡単につくることも可能である。このような
方法においても、放置後に印字したハーフトーンの白筋
は著しく減少した。In FIG. 6A, the radius of the member 7 to be charged is a, the length of the fiber of the brush is b, and the surface movement direction of the member 7 to be charged of the brush is from the vertex of the angle θ 2 of the brush supporting member. When the width to the upstream side of is d,
The angle θ 2 flutters to the downstream side of the surface moving direction of the charged body.
To set. That is, by defining the value of θ 2 so as to satisfy tan θ 2 <(a + b) / d, the tip of the brush does not come into contact with the surface of the body to be charged in a reverse bristling manner. As a result, there are no bristles that are raised up against the charged body on the upstream side of the brush, and the white lines in the initial state of low humidity are reduced. Moreover, according to this method, as shown in FIG.
As shown in (b), since the density of the amount of the fibers at the upstream side of the contact area between the conductive fiber 1 and the member to be charged with respect to the member to be charged becomes large, stable charging can be performed with a small charging width. It will be possible. In addition, when such a brush charger is used in an electrophotographic apparatus, an angle is provided in advance in a part of the process cartridge as shown in FIG. 7, and the brush charger is attached to the base cloth together therewith. It is also possible to make easily with. Even in such a method, halftone white streaks printed after being left standing were significantly reduced.
【００１６】また、これまでのブラシと、ブラシ支持部
材を用いても、白筋を減少させることが可能である。こ
れはまず、前記したような従来のブラシ帯電装置におい
て、導電性ブラシが被帯電体表面と最初に当接するブラ
シ上流側においてのみ、帯電と同時に除電をおこなうこ
とによって可能となる。白筋の原因にブラシ上流側で
の、はみ出し毛が影響していることは既に説明した。そ
こで特に電子写真方式を用いた装置においては図８に示
すように、帯電部の前段に存在する除電ランプ１２によ
る除電光を故意にブラシ前半部分にも照射し、ブラシ上
流部分の帯電を除電してしまう。図８はそのように加工
した電子写真方式のプロセスカートリッジの例である。
ここでブラシ繊維１は基布２に高密度に植毛され、また
通常は黒色であるため、除電ランプ１２による除電光
は、ブラシ帯電器の内側に入ってくることなく、ブラシ
上流側を除いた部分で良好な帯電が行われる。それによ
ってブラシ上流側での帯電ムラは減少する。Further, it is possible to reduce white streaks by using the conventional brush and the brush supporting member. This can be achieved by first, in the conventional brush charging device as described above, removing charges simultaneously with charging only on the brush upstream side where the conductive brush first contacts the surface of the body to be charged. It has already been explained that the protruding hair on the upstream side of the brush affects the cause of the white streaks. Therefore, particularly in the apparatus using the electrophotographic method, as shown in FIG. 8, the static elimination light by the static elimination lamp 12 existing in the preceding stage of the charging section is intentionally applied to the first half of the brush to eliminate the static electricity in the upstream part of the brush. Will end up. FIG. 8 shows an example of an electrophotographic process cartridge processed as described above.
Here, since the brush fibers 1 are densely planted on the base cloth 2 and are usually black, the charge removal light by the charge removal lamp 12 does not enter the inside of the brush charger, but the brush upstream side is removed. Good charging is performed in the part. As a result, uneven charging on the upstream side of the brush is reduced.
【００１７】次に、同じように従来のブラシ帯電器を用
いて白筋を減少させる別方法について説明する。それ
は、固定型のブラシを帯電器として使用した画像形成装
置で、ブラシ帯電器をあらかじめ被帯電体表面に当接し
ておいて、装置の電源投入後、装置使用前に被帯電体を
数分間ブラシに対して面移動させ、ブラシ繊維に予め一
定方向の癖をつけてから使用するというものである。ま
た、そのときにブラシに所定のバイアスを印加するとさ
らに効果がある。Next, another method for reducing white streaks using a conventional brush charger will be described. It is an image forming device that uses a fixed brush as a charging device.The brush charging device is brought into contact with the surface of the charged object in advance, and the charged object is brushed for several minutes before the device is turned on after the power is turned on. With respect to the brush fiber, the brush fiber is moved in a plane, and the brush fiber is preliminarily used in a certain direction. Further, at that time, it is more effective to apply a predetermined bias to the brush.
【００１８】実験では、解像度３００dpi 、印心速度８
枚／分の反転現像方式のレーザプリンタを使用した。被
帯電体はマイナス帯電の有機感光体ドラムを使用してい
る。ブラシ帯電器は、レーヨンにカーボンを分散させた
繊維を使用し、ブラシ全体の抵抗値は１０5 Ω程度であ
る。低湿環境において、新しい固定ブラシ帯電器で初期
から印字したもの、また１２分間（約１００枚分）通紙
せずに、通電もしないで感光体を回転させた後に網点面
積率５０％のハーフトーン画像を印字したもの、そし
て、ブラシに−０．５〜−１．３ｋｖの定電圧バイアス
を印加しながら１２分間、通紙せずに感光体を回転させ
たもののハーフトーン画像における白筋の状態を示す。
また、これまでの説明で紹介した、被帯電体に曲率を合
わせたブラシ帯電器や、斜毛処理をおこなったブラシ、
除電光をブラシ上流側に故意に照射したブラシについて
の結果も同時に比較すると次表のようになる。In the experiment, the resolution was 300 dpi and the centering speed was 8
A reversal development type laser printer of sheets / minute was used. The member to be charged uses a negatively charged organic photosensitive drum. The brush charger uses a fiber in which carbon is dispersed in rayon, and the resistance value of the entire brush is about 10 5 Ω. Printed from the beginning with a new fixed brush charger in a low-humidity environment. Half of the halftone dot area ratio is 50% after rotating the photoconductor without passing electricity for 12 minutes (about 100 sheets) without passing electricity. White lines in the halftone image of the one printed with the tone image and the one rotating the photoconductor without passing the paper for 12 minutes while applying a constant voltage bias of -0.5 to -1.3 kv to the brush. Indicates the status.
In addition, the brush charger introduced in the explanation so far, which has a curvature matched to the body to be charged, and the brush that has been subjected to bevel treatment,
The following table shows the results of the brushes that were intentionally irradiated with the static elimination light on the upstream side, when compared at the same time.
【００１９】[0019]
【表１】
ブラシの幅は全て９mm、繊維の長さは４mmである。感光
体に対する食い込み量は、食毛したブラシ繊維全面が感
光体に当接する範囲で、できるだけ浅く設定した。感光
体径は３０mmφである。これによると、感光体と同曲率
の部材に取り付けたブラシを使用すると白筋が少ない
が、普通のブラシに通電しながら約１００枚分通紙せず
に感光体を回転させた後に印字をおこなうだけでも、ほ
ぼ同じように白筋が減少することがわかる。また、ブラ
シに通電処理をおこなわなくても、ある程度白筋が減少
することがわかる。すなわち、固定ブラシに対して感光
体表面を当接して、予め数分間回転させてやることで、
ブラシ毛に一定方向に癖がつき、斜毛処理した場合と同
じような効果が得られるわけである。通電するバイアス
については、０．５ｋｖ以下では通電処理しない場合と
大差は見られなかったが、０．８ｋｖ以上では、白筋が
さらに減少した。通常使用するバイアスは−１．０ｋｖ
程度なので、通常のおよそ８割以上の電圧を通電する
と、白筋減少に効果が見られる。[Table 1] The width of all the brushes is 9 mm and the length of the fibers is 4 mm. The amount of bite into the photoconductor was set as shallow as possible within the range in which the entire surface of the brushed brush fiber was in contact with the photoconductor. The photoconductor diameter is 30 mmφ. According to this, when a brush attached to a member having the same curvature as the photoconductor is used, there are few white stripes, but printing is performed after rotating the photoconductor without passing about 100 sheets while energizing a normal brush. It can be seen that the white streak is reduced almost in the same way. Further, it can be seen that the white stripes are reduced to some extent even if the brush is not energized. That is, by contacting the surface of the photoconductor with the fixed brush and rotating it for several minutes in advance,
The bristles have a certain tendency in a certain direction, and the same effect as that obtained when the bristles are treated can be obtained. Regarding the bias for energizing, no significant difference was observed at 0.5 kv or less as compared with the case where no energizing was performed, but at 0.8 kv or more, white streaks were further reduced. Normally used bias is -1.0 kv
Since it is only about 80% of the normal voltage, it is effective in reducing white streaks.
【００２０】斜毛処理をおこなったブラシについては、
斜毛角度の条件内に入っていると筋が少なく、範囲外の
条件では前者と比較すると白筋が多い。また角度をつけ
た部材に取り付けたブラシについても同様で、条件の範
囲に入っているものは、筋が減少するが、範囲外のもの
は範囲内のものに比べると筋が多く発生する。しかし、
いずれも、なにも対策を施さなかったブラシの初期状態
に比べると明らかに白筋が少なくなった。また除電光を
ブラシ上流側に照射したブラシ帯電器においても、無対
策のものに比べて白筋が少なく、効果が見られた。Regarding the brush that has been subjected to the bristling treatment,
The number of streaks is small when the angle is within the angle of slant, and the number of white lines is large when the condition is out of the range as compared with the former. The same applies to the brush attached to the angled member. When the brush is in the range of the condition, the streak is reduced, but when the brush is out of the range, the streak is generated more than in the range. But,
In all cases, white streaks were apparently reduced compared to the initial state of the brush without any measures. In addition, even in the brush charger in which the charge removing light was irradiated to the upstream side of the brush, the white streak was less than that in the case of no countermeasure, and the effect was seen.
【００２１】次に、ブラシ繊維を被帯電体に均一に当接
させる以外にも、白筋を減少させる方法がある。これは
ブラシ帯電器に、直流に加えて、被帯電体が一様に収束
帯電を開始する電圧未満の交流バイアスを重畳するとい
うものである。これについても前記した反転現像方式の
レーザプリンタを例にあげて説明する。被帯電体はマイ
ナス帯電の感光体ドラムであり、帯電はマイナス側に行
われ、感光体の表面電位がマイナス側に高ければ画像上
では白くなり、プラス側に近ければ画像上では黒くな
る。ここではマイナス側の電圧が高いほど、電位が高
い、大きい、という表現を用いて説明する。Next, there is a method of reducing white streaks other than uniformly contacting the brush fibers with the member to be charged. In this method, in addition to direct current, an AC bias less than the voltage at which the body to be charged uniformly starts convergent charging is superimposed on the brush charger. This will also be described by taking the above-described reversal development type laser printer as an example. The member to be charged is a negatively charged photosensitive drum, and the charging is performed on the negative side. If the surface potential of the photosensitive member is high on the negative side, it becomes white on the image, and if it is close to the positive side, it becomes black on the image. Here, the higher the negative voltage is, the higher the potential is, and the larger the potential is.
【００２２】ブラシ帯電器に直流バイアスを印加してい
くと、図９のようになる。これによると、感光体の表面
電位はブラシ印加電圧が−５００ｖ程度になったところ
で突然上昇し初め、ほぼ直線的に上昇し、ブラシ帯電器
に−１０００ｖ印加したときには感光体はおよそ−５０
０ｖに帯電する。すなわち、感光体の帯電が開始すると
きのブラシ印加電圧は−５００ｖ程度で、感光体はブラ
シ帯電器とこの程度の電位差があって、はじめて帯電
し、その電位差はブラシ印加電圧が変化してもほぼ一定
に保たれる。そしてこれは放電現像に特有な性質であ
る。さらにブラシ帯電においても、帯電器の極近傍から
は微量のオゾンが発生（コロナ法電気の約１０-3）して
おり、ブラシ帯電においても放電による帯電が支配的で
あると考えられる。ここで白筋というのは、ブラシ帯電
器のなかの不良な繊維やムダ毛などによる通常の放電に
よらない帯電現像により、表面電位が他の部分に比べて
局所的に高くなってしまった部分であることは既に説明
した。そして直流バイアスのみでは一度高くなってしま
った表面電位はもう下げることができない。When a DC bias is applied to the brush charger, it becomes as shown in FIG. According to this, the surface potential of the photoconductor starts to rise suddenly when the applied voltage of the brush becomes about −500 V, and rises almost linearly, and when the brush charger is applied −1000 V, the surface potential of the photoconductor is about −50.
It is charged to 0v. That is, the brush applied voltage at the start of charging of the photosensitive member is about -500 V, and the photosensitive member is charged for the first time with a potential difference of this level with the brush charger, and the potential difference is maintained even if the brush applied voltage changes. It is kept almost constant. And this is a characteristic peculiar to discharge development. Further, even in brush charging, a very small amount of ozone is generated in the immediate vicinity of the charger (about 10 −3 of corona electricity), and it is considered that charging by discharge is also dominant in brush charging. Here, the white streaks are the areas where the surface potential is locally higher than other areas due to the charge development that does not rely on normal discharge due to defective fibers or waste hair in the brush charger. That is already explained. And the surface potential, which has been once high, can no longer be reduced only by DC bias.
【００２３】次に、直流バイアスを−５００ｖに固定し
て、そこに交流バイアスを徐々に重畳していくと感光体
の表面電位は図１０のように変化する。図１０による
と、交流電圧が４００ｖ程度までは、表面電位は一定の
傾きで上昇する。そしてこのときの表面電位は、直流の
みで、直流に交流を重畳したときの電圧の極大値をブラ
シ帯電器に印加したときの値にほぼ等しくなっている。
直流のみで帯電させたときの感光体の表面電位を点線で
示す。しかし交流電圧が４００ｖを越えるとその傾きは
非常に小さくなり、徐々には上昇していくものの、いわ
ゆる収束域にはいる。ここで、収束帯電域の領域内であ
る交流電圧が６００ｖの場合のブラシ印加バイアスと感
光体の表面電位の概念図を第１１図に示す。第１１図に
よれば、ブラシバイアスの極大値はおよそ−１３４０ｖ
（−５００−６００×１．４）であり、感光体はそのと
き、印加バイアスとおよそ５００ｖの差を持って−８０
０ｖ程度に帯電する。一方、ブラシバイアスの極小値は
およそ＋３４０ｖ（−５００＋６００×１．４）となり
同様な理論から感光体は−１５０ｖ程度に帯電する。す
なわち、プラス方向とマイナス方向の放電による帯電
が、ブラシ帯電器と感光体とが接触している全域に渡っ
て繰り返して行われることになる。そして最終的な感光
体の表面電位は、結局のところブラシ帯電器が感光体と
最後に当接していた部分におけるブラシバイアスによっ
て決定される。ブラシ帯電器が感光体と離れる最下流側
では、ブラシ繊維は感光体の軸方向に沿って完全な直線
状態にはなっておらず、場所によってはみ出した繊維が
存在している。すなわち表面電位はそれら繊維の影響を
受け、−１５０〜−８００ｖの範囲に散らばってしまい
均一になることはない。そのような条件でハーフトーン
画像を印字しても、表面電位の高い部分は白くなり、低
い部分は黒くなり良好な画像が得られない。Next, when the DC bias is fixed at -500 V and the AC bias is gradually superposed thereon, the surface potential of the photosensitive member changes as shown in FIG. According to FIG. 10, the surface potential rises with a constant inclination up to an AC voltage of about 400V. The surface potential at this time is only DC, and is almost equal to the value when the maximum value of the voltage when AC is superimposed on DC is applied to the brush charger.
The surface potential of the photoconductor when charged only with direct current is shown by a dotted line. However, when the AC voltage exceeds 400 V, the slope becomes very small and gradually rises, but within the so-called convergence range. Here, FIG. 11 shows a conceptual diagram of the brush application bias and the surface potential of the photoconductor when the AC voltage in the area of the convergent charging area is 600 v. According to FIG. 11, the maximum value of the brush bias is about -1340v.
(−500−600 × 1.4), and the photosensitive member then has a difference of about 500 v from the applied bias and −80.
It is charged to about 0v. On the other hand, the minimum value of the brush bias is about + 340v (-500 + 600x1.4), and the photoreceptor is charged to about -150v from the same theory. That is, the charging by the positive and negative discharges is repeatedly performed over the entire area where the brush charger and the photoconductor are in contact with each other. The final surface potential of the photoconductor is ultimately determined by the brush bias in the portion where the brush charger is finally in contact with the photoconductor. On the most downstream side where the brush charger separates from the photoconductor, the brush fibers are not in a completely linear state along the axial direction of the photoconductor, and some fibers protrude depending on the location. That is, the surface potential is affected by those fibers and is scattered in the range of −150 to −800 v, and is not uniform. Even if a halftone image is printed under such conditions, a portion having a high surface potential becomes white and a portion having a low surface potential becomes black, and a good image cannot be obtained.
【００２４】一方、図１０において傾きが大きい直線部
分、つまり収束域未満の領域である交流電圧が３５０ｖ
の場合は第１２図のようになる。第１２図は直流電圧−
５５０ｖに交流電圧３５０ｖを重畳させた場合で、これ
によれば、ブラシバイアスの極大値は−１０４０ｖ（−
５５０−３５０×１．４）であり、このとき感光体はお
よそ−５５０に帯電する。そこにブラシバイアスの極小
値である−６０ｖが印加されても感光体との電位差が既
におよそ５００ｖ程度で、ほとんどプラス側への放電が
発生しない。すなわち、ブラシバイアスが極大値のとき
に帯電された感光体の表面電位が、ブラシと被帯電体が
当接している間にほとんど変化せずそのまま保存され、
最終的な電位は−５５０ｖ程度に収束する。つまり直流
のみをブラシ帯電器に印加した場合と同じように、適当
な表面電位に帯電した部分の電位は下げられることな
い。図１０で示した交流電圧が４００ｖ未満の領域とい
うのは、プラス側の放電による帯電が発生しない、いわ
ゆる交流電圧が、感光体が収束帯電を開始する未満の領
域なのである。ここで白筋部分について考えると、白筋
というのは、表面電位が局所的に高くなっている部分な
ので、白筋部分のみがブラシバイアスの極小値のときに
電位差が５００ｖ、ここでいう放電開始電圧を越えるこ
とになる。そしてプラス側に放電され電位が下がり、電
位差５００ｖになるところで落ちつくことになる。すな
わち白筋部分だけが電位が下がり筋が減少する。また、
もしもこのとき通常の放電によらない帯電がプラス側に
発生し、表面電位が低い部分が発生したとしても、その
後に極大値である−１０４０ｖが印加されたときに正常
な電位に復活する。つまりブラシ最下流側で、そのよう
な異常な帯電が発生しさえしなければ帯電ムラになるこ
とはなく、白筋は勿論のこと、黒筋が増加するようなこ
ともほとんどない。On the other hand, in FIG. 10, a linear portion having a large inclination, that is, an AC voltage which is a region less than the convergence region is 350V.
In the case of, the result is as shown in FIG. Fig. 12 shows DC voltage
According to this, when the AC voltage 350v is superimposed on 550v, the maximum value of the brush bias is -1040v (-
550-350 × 1.4), at which time the photoreceptor is charged to approximately −550. Even if a minimum value of the brush bias of −60 V is applied thereto, the potential difference from the photoconductor is already about 500 V, and almost no discharge to the positive side occurs. That is, the surface potential of the photoconductor charged when the brush bias has the maximum value is almost unchanged during the contact between the brush and the charged body, and is stored as it is.
The final potential converges to about -550v. That is, as in the case where only the direct current is applied to the brush charger, the potential of the portion charged to an appropriate surface potential is not lowered. The region where the AC voltage is less than 400 V shown in FIG. 10 is a region where the charging due to discharge on the positive side does not occur, that is, the so-called AC voltage is less than when the photosensitive member starts convergent charging. Considering the white streak part here, since the white streak is a part where the surface potential is locally high, the potential difference is 500 v when only the white streak part has the minimum value of the brush bias, and the discharge start here is started. The voltage will be exceeded. Then, it is discharged to the positive side and the potential drops, and then it settles down when the potential difference reaches 500 v. That is, only the white streak part has a reduced potential and the streak decreases. Also,
At this time, even if charging which is not due to normal discharge is generated on the positive side and a portion having a low surface potential is generated, it is restored to a normal potential when a maximum value of -1040v is applied thereafter. That is, even if such abnormal charging does not occur on the most downstream side of the brush, uneven charging does not occur, and black streaks as well as white streaks hardly increase.
【００２５】実際にレーザプリンタを用いてハーフトー
ン画像を印字して評価した結果を次に示す。環境は高温
多湿で、ブラシ帯電器は従来タイプの新品を使用し、バ
イアスを各種かえて実験をおこなった。プリンタは上述
した方式のものを使用し、ブラシ帯電器を取り付けてか
ら５枚目の画像を評価した。The results of actually printing and evaluating a halftone image using a laser printer are shown below. The environment was hot and humid, and the brush charger used was a new type of conventional type, and various biases were changed and experiments were conducted. The printer used was the one described above, and the fifth image was evaluated after the brush charger was attached.
【００２６】[0026]
【表２】
直流に対して重畳する交流バイアスは実験に使用したブ
ラシ帯電器の場合、３００ｖ〜４００ｖが適正であっ
た。つまり感光体が収束帯電を開始する直前の条件がよ
い。これは図７における帯電開始電圧の−５００ｖとは
少しばかり食い違っている。これは白筋部分の帯電開始
電圧も、表面電位に含まれて測定されてしまうためで、
実際のところ白筋部分は通常の放電以外の帯電によっ
て、帯電開始電圧がプラス方向に２００ｖ程度シフトし
ている。収束帯電が開始する直前の領域というのは、す
なわち図１０において、直線の傾きが変化する直前部分
であり、この領域において白筋減少に大きな効果が見ら
れるのである。これはつまり、筋部分以外の領域を、放
電によって電位が下げられるほぼ境界の電位にすること
で、わずかに電位が上昇している微妙な白筋部分さえも
プラス側の放電により減少することができるためであ
る。[Table 2] In the case of the brush charger used in the experiment, 300 V to 400 V was appropriate for the AC bias superimposed on the DC. That is, the condition immediately before the photosensitive body starts the convergent charging is preferable. This is slightly different from the charging start voltage of −500 V in FIG. This is because the charging start voltage of the white streaks is also included in the surface potential and measured,
Actually, the charging start voltage of the white streak portion is shifted by about 200 V in the positive direction due to charging other than normal discharge. The area immediately before the start of the convergent charging is the area immediately before the inclination of the straight line changes in FIG. 10, and a great effect can be seen in reducing the white streaks in this area. In other words, by setting the areas other than the muscles to the potential at the boundary where the potential is lowered by the discharge, even the subtle white muscles where the potential is slightly increased can be reduced by the positive discharge. Because you can.
【００２７】また周波数に関しては、ブラシの周波数の
追従性に関係してくるが、実験をおこなったブラシでは
１００Ｈｚ〜８００Ｈｚが適正値であった。ブラシの周
波数を２００Ｈｚにまで低くすると、ブラシ中にわずか
に混在する不良な繊維やムダ毛などの影響により電位が
高くなる部分が、筋状にはらずに網点状になる。そして
電位の高い網点部分どうしの間の領域は正常な表面電位
になり、結果的に電位の高い白筋部分の面積は減少する
ことになる。また、網点状になるため筋などの帯電ムラ
が肉眼ではとらえにくくなる。そして結果的には筋自体
が目立たなくなる。しかし、周波数が高くても効果がな
いわけではなく、白筋は直流バイアスのみを印加したと
きと比べてかなり減少しいている。Regarding the frequency, although it is related to the followability of the frequency of the brush, 100 Hz to 800 Hz was an appropriate value for the brush used in the experiment. When the frequency of the brush is lowered to 200 Hz, the portion where the electric potential becomes high due to the influence of defective fibers and waste bristles slightly mixed in the brush does not become streak-like but halftone dot-like. Then, the area between the high-potential halftone dot portions has a normal surface potential, and as a result, the area of the high-potential white streak portion decreases. In addition, since it becomes a halftone dot pattern, uneven charging such as streaks is difficult to catch with the naked eye. As a result, the muscles themselves become less noticeable. However, even if the frequency is high, it is not ineffective, and the white streak is considerably reduced as compared with the case where only the DC bias is applied.
【００２８】このように、適正な交流バイアスを直流バ
イアスに重畳することによって、感光体表面上に局所的
に電位が高い部分がなくなる。すなわち低湿環境におけ
る白筋に加えて、多湿環境で発生した連続的な白筋をも
大幅に減少させることができる。As described above, by superimposing the appropriate AC bias on the DC bias, there is no locally high potential portion on the surface of the photoconductor. That is, in addition to the white streak in the low humidity environment, continuous white streak generated in the high humidity environment can be significantly reduced.
【００２９】[0029]
【発明の効果】本発明により、固定型の導電性ブラシ帯
電器に特有の帯電むらによる、ハーフトーン画像上の白
筋を減少させることができる。According to the present invention, it is possible to reduce white streaks on a halftone image due to uneven charging peculiar to a fixed-type conductive brush charger.
【図１】（ａ）、（ｂ）、（ｃ）はそれぞれ本発明のー
実施例のブラシカットの順序を示す模式図。1A, 1B, and 1C are schematic views showing the order of brush cutting according to an embodiment of the present invention.
【図２】（ａ）は比較のため示した従来のブラシカット
の一例を示す模式図、（ｂ）は本発明のー実施例のブラ
シカット法の模式図。2A is a schematic view showing an example of a conventional brush cut shown for comparison, and FIG. 2B is a schematic view of a brush cut method according to an embodiment of the present invention.
【図３】（ａ）、（ｂ）は比較のため従来の固定ブラシ
の当接状態を示す模式図。3A and 3B are schematic diagrams showing a contact state of a conventional fixed brush for comparison.
【図４】（ａ）、（ｂ）は前記実施例において施される
斜毛処理条件を示す模式図。4 (a) and 4 (b) are schematic diagrams showing the conditions for the slanting treatment performed in the above-described embodiment.
【図５】（ａ）、（ｂ）は前記斜毛処理の方法のー例の
模式図。5 (a) and 5 (b) are schematic views of an example of the method of the above-mentioned slant treatment.
【図６】（ａ）、（ｂ）はブラシを角度をなす部材にと
りつけた場合の状態を示す模式図。6A and 6B are schematic views showing a state in which a brush is attached to an angled member.
【図７】角度をなす部材がプロセスカートリッジの一部
である実施例の正面図。FIG. 7 is a front view of an embodiment in which the angled member is part of a process cartridge.
【図８】プロセスカートリッジの他の実施例の正面図。FIG. 8 is a front view of another embodiment of the process cartridge.
【図９】直流バイアス印加時の固定ブラシの帯電特性を
示す線図。FIG. 9 is a diagram showing a charging characteristic of a fixed brush when a DC bias is applied.
【図１０】直流バイアスに交流バイアス重畳印加時の固
定ブラシの帯電特性を示す線図。FIG. 10 is a diagram showing a charging characteristic of a fixed brush when an alternating bias is applied to a direct bias.
【図１１】直流５００Ｖに交流６００Ｖを重畳印加した
場合の概念図。FIG. 11 is a conceptual diagram in the case where AC 600V is superimposed and applied to DC 500V.
【図１２】直流５５０Ｖに交流３５０Ｖを重畳印加した
場合の概念図。FIG. 12 is a conceptual diagram in the case where an alternating current of 350 V is superposed on a direct current of 550 V.
１…ブラシ、２…ブラシ基布、３…支持部材、４…カッ
ター、５…ドラム、６…ブラシ支持部材、７…被帯電
体、８…円筒ドラム、９…円筒ドラム、１０…押さえ
板、１１…プロセスカートリッジ、１２…除電ランプ。1 ... Brush, 2 ... Brush base cloth, 3 ... Support member, 4 ... Cutter, 5 ... Drum, 6 ... Brush support member, 7 ... Charged member, 8 ... Cylindrical drum, 9 ... Cylindrical drum, 10 ... Press plate, 11 ... Process cartridge, 12 ... Static elimination lamp.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 藤原 茂 神奈川県川崎市幸区柳町70番地 株式会 社東芝 柳町工場内 (72)発明者 高橋 雅司 神奈川県川崎市幸区柳町70番地 株式会 社東芝 柳町工場内 (56)参考文献 特開 昭63−210862（ＪＰ，Ａ) 特開 平５−241425（ＪＰ，Ａ) 特開 平５−204227（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G03G 15/02 G03G 15/16 103 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeru Fujiwara Shigeru Fujiwara 70 Yanagimachi, Sachi-ku, Kawasaki City, Kanagawa Stock Company Toshiba Yanagimachi Factory (72) Inventor Masashi Takahashi 70, Yanagicho, Kawasaki-shi, Kanagawa Stock Company Toshiba Corporation Yanagimachi Plant (56) Reference JP 63-210862 (JP, A) JP 5-241425 (JP, A) JP 5-204227 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G03G 15/02 G03G 15/16 103
Claims (2)
を被帯電体の表面に当接させて帯電を行うブラシ帯電装
置であり、さらに、前記ブラシが植毛されたブラシ支持
面を有するブラシ支持体を備えているとともに、前記ブ
ラシの毛先が前記被帯電体の表面に当接するように前記
ブラシ支持体が配置され、且つ前記被帯電体の回転によ
りこの被帯電体の表面が前記回転の方向へ移動するとと
もに、前記被帯電体の表面の前記ブラシとの当接部位が
前記ブラシ側に膨出しその当接部位が曲率を有するブラ
シ帯電装置において、 上記ブラシの毛先が前記被帯電体の表面の移動方向に対
して順方向になびくように、前記ブラシの毛に斜毛処理
を施し、この斜毛処理を前記被帯電体の回転の軸方向か
らみた断面で考えた場合、 前記ブラシ支持面と前記ブラシの毛とがなす鋭角の値を
θ1、前記被帯電体の表面の前記ブラシとの当接部位の曲率半
径 をａ、前記ブラシの毛 の長さをｂ、前記曲率半径の曲率中心より前記ブラシ支持体のブラシ
支持面に引いた垂線の該ブラシ支持面との交点から、前
記被帯電体の表面の移動方向を基準とした場合の最上流
側の前記ブラシの毛の基端を支持する前記ブラシ支持面
上の点 までの距離をｃとしたとき、 ｃｏｓθ1＞ｃ／（ａ＋ｂ） となるようにしたことを特徴とするブラシ帯電装置。1. A fixed brush to which a bias voltage is applied.
A brush charging device that charges the surface of the body to be charged by charging
And a brush support on which the brush is implanted.
A brush support having a surface, and
Make sure that the hair tips of the brush touch the surface of the charged body.
A brush support is arranged, and rotation of the charged body causes
When the surface of the charged object of Riko moves in the direction of rotation,
Mostly, the contact portion of the surface of the charged body with the brush is
A bra that bulges toward the brush side and has a contact portion with a curvature
In the electrostatic charging device, the bristles of the brush are subjected to slanting treatment so that the bristles of the brush flutter in the forward direction with respect to the moving direction of the surface of the electrified member. The axis of rotation of
Considering the cross section viewed from above, the value of the acute angle formed by the brush supporting surface and the bristles of the brush is θ 1 , and the curvature half of the contact portion of the surface of the charged body with the brush is half.
The diameter of the brush is b, the length of the bristles of the brush is b, and the brush of the brush support is defined by the center of curvature of the radius of curvature.
From the intersection of the perpendicular drawn to the supporting surface with the brush supporting surface,
The uppermost stream based on the moving direction of the surface of the charged body
Side brush supporting surface that supports the proximal end of the bristles of the brush
A brush charging device characterized in that cos θ 1 > c / (a + b), where c is the distance to the upper point .
を被帯電体の表面に当接させて帯電を行うブラシ帯電装
置であり、さらに、前記ブラシが植毛された第１及び第
２の支持面からなるブラシ支持面を有するブラシ支持体
を備え、前記第１及び第２の支持面の境界部分を折曲部
として前記ブラシ支持体が前記被帯電体側に折曲されて
いるとともに、前記ブラシの毛先が前記被帯電体の表面
に当接するように前記ブラシ支持体が配置され、且つ前
記被帯電体の回転によりこの被帯電体の表面が前記回転
の方向へ移動するとともに、前記被帯電体の表面の前記
ブラシとの当接部位が前記ブラシ側に膨出しその当接部
位が曲率を有するブラシ帯電装置において、 前記ブラシを支持する前記ブラシ支持体と前記被帯電体
との配置関係を、前記被帯電体の回転の軸方向からみた
断面で考えた場合、 前記被帯電体の表面の前記ブラシとの当接部位の曲率半
径 をａ、前記ブラシの毛 の長さをｂ、前記被帯電体の表面の移動方向を基準とした場合の最上
流側の前記ブラシの毛の基端を支持する前記ブラシ支持
面上の点から、前記折曲部までの距離を ｄ、前記被帯電体の表面の移動方向を基準とした場合の最上
流側の前記ブラシの毛の基端を支持する前記ブラシ支持
面上の点と前記折曲部とを結ぶ線と、前記曲率半径の曲
率中心と前記折曲部とを結ぶ線と、がなす鋭角の値を θ
2としたとき、 ｔａｎθ2＜（ａ＋ｂ）／ｄ となるようにしたことを特徴とするブラシ帯電装置。2. A fixed brush to which a bias voltage is applied.
A brush charging device that charges the surface of the body to be charged by charging
And the brushes have first and second bristles.
Brush support having a brush support surface composed of two support surfaces
And a bent portion at the boundary between the first and second support surfaces.
As the brush support is bent toward the charged body
The tip of the brush is the surface of the body to be charged.
The brush support is arranged so as to contact the
The surface of the charged body is rotated by the rotation of the charged body.
In the direction of the
The contact part with the brush bulges toward the brush side and its contact part
In a brush charging device in which the position has a curvature, the brush support for supporting the brush and the body to be charged
From the axial direction of rotation of the charged body
When considered in cross section, the half of the curvature of the contact surface of the charged body with the brush
When the diameter is a, the length of the bristles of the brush is b, and the moving direction of the surface of the charged body is a reference,
The brush support that supports the proximal ends of the bristles on the flow side
When the distance from the point on the surface to the bent portion is d and the moving direction of the surface of the charged body is a reference,
The brush support that supports the proximal ends of the bristles on the flow side
A line connecting a point on the surface and the bent portion, and a curve of the radius of curvature
The value of the acute angle formed by the line connecting the center of ratio and the bent portion is θ
The brush charging device is characterized in that tan θ 2 <(a + b) / d when 2 is set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002019105A JP3399933B2 (en) | 2002-01-28 | 2002-01-28 | Brush charging device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002019105A JP3399933B2 (en) | 2002-01-28 | 2002-01-28 | Brush charging device |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP06630293A Division JP3290743B2 (en) | 1993-03-25 | 1993-03-25 | Manufacturing method of charged brush |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003002436A Division JP3667733B2 (en) | 2003-01-08 | 2003-01-08 | Brush charging device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002236408A JP2002236408A (en) | 2002-08-23 |
| JP3399933B2 true JP3399933B2 (en) | 2003-04-28 |
Family
ID=19192113
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002019105A Expired - Fee Related JP3399933B2 (en) | 2002-01-28 | 2002-01-28 | Brush charging device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3399933B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7734223B2 (en) | 2005-09-15 | 2010-06-08 | Ricoh Company, Ltd. | Image forming apparatus and process cartridge employing the same having brush roller charger |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4868834B2 (en) * | 2005-11-28 | 2012-02-01 | 京セラミタ株式会社 | Image forming apparatus and image forming method |
| JP2007147983A (en) * | 2005-11-28 | 2007-06-14 | Kyocera Mita Corp | Image forming apparatus and method |
-
2002
- 2002-01-28 JP JP2002019105A patent/JP3399933B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7734223B2 (en) | 2005-09-15 | 2010-06-08 | Ricoh Company, Ltd. | Image forming apparatus and process cartridge employing the same having brush roller charger |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002236408A (en) | 2002-08-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4124988B2 (en) | Image forming apparatus | |
| JP3399933B2 (en) | Brush charging device | |
| JPH05107875A (en) | Recorder | |
| JP3290743B2 (en) | Manufacturing method of charged brush | |
| EP0642063B1 (en) | charging device and image forming apparatus containing the charging device | |
| US6014529A (en) | Charging apparatus | |
| US6909868B2 (en) | Brush charger for static-charging a photosensitive member and image forming apparatus | |
| KR100367265B1 (en) | Image forming apparatus | |
| JP3667733B2 (en) | Brush charging device | |
| JP2002169358A (en) | Contact electrifying device | |
| JP5062984B2 (en) | Image forming apparatus and image forming method | |
| JP3223007B2 (en) | Image forming device | |
| JP3140313B2 (en) | Multicolor image forming device | |
| JP4522172B2 (en) | Corona discharge device and image forming apparatus having the same | |
| JPH05150564A (en) | Contact electrification method and device therefor | |
| JP3397688B2 (en) | Image forming apparatus and process cartridge | |
| JP3261746B2 (en) | Charging device and image forming device | |
| JPH0483284A (en) | Image forming device | |
| JP3579359B2 (en) | Method for manufacturing contact charging member | |
| JP4868834B2 (en) | Image forming apparatus and image forming method | |
| JP2005173283A (en) | Proximity electrifying device | |
| JPH07301971A (en) | Method and device for electrostatically charging photoreceptor | |
| JP2000089543A (en) | Electrification member, electrification device and image forming device | |
| JPH086357A (en) | Brush charging mechanism | |
| JP2004287236A (en) | Contact electrification device and image forming apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20030204 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080221 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090221 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100221 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100221 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110221 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110221 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120221 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120221 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130221 Year of fee payment: 10 |
|
| LAPS | Cancellation because of no payment of annual fees |