JPH0876559A - Charging method for photoreceptor and image forming device - Google Patents

Charging method for photoreceptor and image forming device

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Publication number
JPH0876559A
JPH0876559A JP23960394A JP23960394A JPH0876559A JP H0876559 A JPH0876559 A JP H0876559A JP 23960394 A JP23960394 A JP 23960394A JP 23960394 A JP23960394 A JP 23960394A JP H0876559 A JPH0876559 A JP H0876559A
Authority
JP
Japan
Prior art keywords
photoconductor
electric field
photoreceptor
image forming
light
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.)
Withdrawn
Application number
JP23960394A
Other languages
Japanese (ja)
Inventor
Tomoko Takahashi
朋子 高橋
Masafumi Kadonaga
雅史 門永
Tomoki Kato
知己 加藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP23960394A priority Critical patent/JPH0876559A/en
Publication of JPH0876559A publication Critical patent/JPH0876559A/en
Withdrawn legal-status Critical Current

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  • Electrophotography Configuration And Component (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)

Abstract

PURPOSE: To charge a photoreceptor while hardly producing ozone by applying an electric field in the direction that the carrier can move on a photoreceptor while irradiating the photoreceptor with light so that the carrier produced is moved to the surface to charge the photoreceptor. CONSTITUTION: An electric field is applied to a photoreceptor 5 comprising a conductive base body 3 and a photosensitive layer 4 by applying voltage from an external power supply to a transparent electrode 2 formed on a transparent supporting body 1,/while the photoreceptor 5 is irradiated with light 6. When the photoreceptor 5 is irradiated with light in a photosensitive wavelength region, pairs of holes and electrons are produced in the photoreceptor 5. When an electric field is applied to the photoreceptor 5 in this state, the carrier (holes or electrons) according to the direction of the electric field moves to the surface of the photoreceptor 5 and charges the surface of the photoreceptor 5. It is enough when the carrier mobility of the photoreceptor 5 under an electric field applied is in such a degree that the carrier reaches the surface of the photoreceptor 5 during the photoreceptor passes the area where the electric field is applied. By selectively irradiating the photoreceptor with light according to the image information, an electrostatic latent image can be formed.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、複写機、ファクシミ
リ、プリンター等の画像形成装置における感光体に係
り、詳しくは、感光体に静電潜像を形成して画像を形成
する画像形成装置における感光体帯電方法及び画像形成
装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor in an image forming apparatus such as a copying machine, a facsimile or a printer, and more particularly to an image forming apparatus for forming an electrostatic latent image on the photoconductor to form an image. The present invention relates to a photoconductor charging method and an image forming apparatus.

【０００２】[0002]

【従来の技術】従来、電子写真方式の一つであるカール
ソンプロセスを用いた一般的な画像形成装置では、感光
体を一様に初期帯電した後に、画像パタ−ンを露光して
感光体上に静電潜像を形成し、現像部でトナーを付着さ
せることにより静電潜像を顕像化し、転写部で紙などに
トナー像を転写し、その後定着でトナー像を定着して画
像を形成していた。この初期帯電の方法としては、コロ
ナ帯電方式が従来から最も一般的に用いられている。し
かし、このコロナ帯電方式は感光体から離れたところ位
置する電極からの放電で帯電を行うため多量のオゾンが
発生してしまう。また、コロナ放電を行わせるために
は、約４ｋＶ以上という高電圧の印加が必要である。そ
こで、このような不具合が解消できるものとして、ロー
ラ帯電方式が近年用いられてきているが、ローラ帯電方
式の場合も放電を利用するため、コロナ帯電方式と比較
すれば少量ではあるが、オゾンが発生し環境に悪影響を
及ぼす。2. Description of the Related Art Conventionally, in a general image forming apparatus using the Carlson process, which is one of electrophotographic methods, after the photoconductor is uniformly initially charged, the image pattern is exposed to expose the photoconductor. An electrostatic latent image is formed on the surface, the toner is attached at the developing unit to visualize the electrostatic latent image, the toner image is transferred to paper or the like at the transfer unit, and then the toner image is fixed by fixing to form the image. Had formed. As a method of this initial charging, the corona charging method has been most commonly used conventionally. However, in this corona charging method, a large amount of ozone is generated because charging is performed by discharge from an electrode located away from the photoconductor. Further, in order to perform corona discharge, it is necessary to apply a high voltage of about 4 kV or higher. Therefore, the roller charging method has been used in recent years as a solution to such a problem, but since the discharge is also used in the roller charging method, ozone is generated in a small amount compared to the corona charging method. Occurs and adversely affects the environment.

【０００３】また、小型化、低コスト化等の要求から前
述のカールソンプロセスに比して少ない工程で画像形成
するためのプロセスも種々提案されている。例えば、初
期帯電を省略できるものとして、フォトチャージ法があ
る。この方法は酸化亜鉛−樹脂感光層を電界なしで選択
的に露光し、感光層の光照射側が正に分極した状態をさ
せて静電潜像を形成するものである。ところが、この方
法により形成された静電潜像は電位が２００ｍＶ程度し
かなく利用できる現像方式が制限され、また光感度はカ
ールソンプロセスの千分の１程度しかない。Further, various processes have been proposed for forming an image in a smaller number of steps as compared with the above-mentioned Carlson process in order to reduce the size and cost. For example, there is a photo charge method that can omit the initial charging. According to this method, the zinc oxide-resin photosensitive layer is selectively exposed without an electric field so that the light irradiation side of the photosensitive layer is positively polarized to form an electrostatic latent image. However, the electrostatic latent image formed by this method has a potential of only about 200 mV, which limits the developing method that can be used, and the photosensitivity is only about one thousandth of that of the Carlson process.

【０００４】[0004]

【発明が解決しようとする課題】本発明は以上の背景に
鑑みなされたものであり、その目的とするところは、コ
ロナ帯電方式に比して小さな電圧を利用しオゾンをほと
んど発生させることなく感光体を帯電でき、しかも、静
電潜像形成工程の簡略化にも使用できる新規な感光体帯
電方法及び該帯電方法を実施するための画像形成装置を
提供することである。SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and an object of the present invention is to use a small voltage as compared with a corona charging method and generate almost no ozone. It is an object of the present invention to provide a novel photoreceptor charging method that can charge the body and can also be used for simplifying the electrostatic latent image forming process, and an image forming apparatus for carrying out the charging method.

【０００５】[0005]

【課題を解決するための手段】本発明の感光体帯電方法
においては、感光体に対しキャリアが移動可能な方向に
電界を作用させると共に光を照射する。感光体に感光波
長域の光が照射されると、感光体内部では、正孔と電子
の対が発生する。この時感光体内部に電界が作用してい
ると電界の方向にしたがったキャリア（正孔あるいは電
子）が、感光体表面に到達する。例えば、図１におい
て、透明支持体１に設けられた透明電極２に外部電源か
ら電圧を印加することで導電性基体３と感光体層４とか
らなる感光体５に電界を作用させる。電界を作用させて
いる間に、光６を照射し、感光体表面を帯電させてい
る。電界作用下での感光体内のキャリア移動度は、電界
作用領域幅を感光体が通過する間に、キャリアが感光体
表面に到達する程度であれば良い。In the method of charging a photosensitive member according to the present invention, an electric field is applied to the photosensitive member in a direction in which a carrier can move and light is emitted. When the photosensitive member is irradiated with light in the photosensitive wavelength range, holes and electron pairs are generated inside the photosensitive member. At this time, if an electric field is acting inside the photoconductor, carriers (holes or electrons) that follow the direction of the electric field reach the surface of the photoconductor. For example, in FIG. 1, by applying a voltage from an external power source to the transparent electrode 2 provided on the transparent support 1, an electric field is applied to the photoconductor 5 composed of the conductive substrate 3 and the photoconductor layer 4. While the electric field is applied, the light 6 is irradiated to charge the surface of the photoconductor. The carrier mobility in the photoconductor under the action of an electric field may be such that the carriers reach the surface of the photoconductor while the photoconductor passes through the width of the electric field acting region.

【０００６】上記感光体としては感光体層が積層型のも
のと単層型のものいずれも使用できる。図２（ａ），
（ｂ）は積層型のものについての説明図、図２（ｃ），
（ｄ）は単層型のものについての説明図である。図２
（ａ）中、７は電荷輸送層、８は電荷発生層、９は導電
性基体である。また図２（ｃ）中、７は単一の感光体
層、８は模式的に示した感光材料部分である。そして１
０が電界形成のための対向電極を示す。本発明において
は、感光体に電界を作用させると共に光を照射するが、
これらの説明図では説明の便宜上のため光を当てるの
と、電界を作用させるのを別々に示した。図２（ａ）や
（ｃ）に示すように、光が照射されると両者とも電荷発
生層８や感光材料部分８で電荷が発生する。そして、図
示の例では、積層型では正孔が、単層型では電子が、そ
れぞれ電界の作用を受けて感光体表面に移動して感光体
表面は帯電する。As the above-mentioned photoconductor, either a multi-layer photoconductor layer or a single photoconductor layer can be used. 2 (a),
(B) is an explanatory view of a laminated type, FIG. 2 (c),
(D) is an explanatory view of a single layer type. Figure 2
In (a), 7 is a charge transport layer, 8 is a charge generation layer, and 9 is a conductive substrate. Further, in FIG. 2C, 7 is a single photoconductor layer, and 8 is a photosensitive material portion schematically shown. And 1
Reference numeral 0 indicates a counter electrode for forming an electric field. In the present invention, an electric field is applied to the photoreceptor and light is emitted,
For convenience of explanation, in these explanatory diagrams, the application of light and the application of an electric field are shown separately. As shown in FIGS. 2A and 2C, when light is irradiated, charge is generated in the charge generation layer 8 and the photosensitive material portion 8 in both cases. In the illustrated example, holes in the stacked type and electrons in the single layer type are moved to the surface of the photoconductor by the action of the electric field, and the surface of the photoconductor is charged.

【０００７】よって、上記光照射を感光体表面に均一に
おこなうことにより、感光体表面の一様帯電が可能であ
り、また、上記光の照射を画像情報に基づいて選択的に
行うことにより、静電潜像の形成が可能である。Therefore, by uniformly irradiating the surface of the photoconductor with the light, it is possible to uniformly charge the surface of the photoconductor, and by selectively irradiating the light based on image information, It is possible to form an electrostatic latent image.

【０００８】そして、本発明の光照射は、感光体の背面
側から行うこともできる。この場合には、例えば図３に
示すように、感光体１１を、透支持体１２上に透明電極
層１３及び感光層１４を形成して構成し、透明支持体１
２の側から光を照射する。ここで、透明とは、露光光波
長を透過することを意味する。また、光１３を照射する
際に感光体には電界が作用している必要があるため透明
電極１４と感光体層１５を挾んで反対の側には、対向電
極１６が配設する。そして、両電極間に電界を作用させ
るために、透明電極に電圧を印加する又は対向電極に電
圧を印加する。ここで、他のプロセス（現像・転写な
ど）との関係上、対向電極１６に電圧を印加し、透明電
極１４を接地することが望ましい。The light irradiation of the present invention can be performed from the back side of the photoconductor. In this case, for example, as shown in FIG. 3, the photosensitive member 11 is configured by forming the transparent electrode layer 13 and the photosensitive layer 14 on the transparent support 12, and the transparent support 1
Irradiate light from the side of 2. Here, “transparent” means transmitting the wavelength of exposure light. Further, since an electric field needs to be applied to the photoconductor when the light 13 is irradiated, the counter electrode 16 is provided on the opposite side of the transparent electrode 14 and the photoconductor layer 15. Then, in order to apply an electric field between both electrodes, a voltage is applied to the transparent electrode or a voltage is applied to the counter electrode. Here, in consideration of other processes (development, transfer, etc.), it is desirable to apply a voltage to the counter electrode 16 and ground the transparent electrode 14.

【０００９】そして、本発明の帯電方法では、上記光を
感光体表面に選択的に照射すれば、部分的にキャリアが
発生させて表面を部分的に帯電させことにより、感光体
表面に静電潜像を形成できる。ここで、キャリアは、移
動中に多少感光体面方向に拡がるので、シャ−プな潜像
を形成するためには、感光体は薄い方が望ましい。In the charging method of the present invention, when the surface of the photoconductor is selectively irradiated with the above light, carriers are partially generated and the surface is partially charged, so that the surface of the photoconductor is electrostatically charged. A latent image can be formed. Here, since the carrier spreads in the direction of the surface of the photosensitive member to some extent during movement, it is desirable that the photosensitive member is thin in order to form a sharp latent image.

【００１０】そして、本発明の感光体帯電方法を用いる
画像形成装置は、上記電界を形成するための電極部材
を、感光体表面に対向配置して構成する。この感光体表
面に対向した電極部材（以下、対向電極部材という）の
表面には、高抵抗層を設けることが望ましい。ここで、
高抵抗とは、感光体上に帯電した電荷の対向電極部材へ
の注入が起こらない程度に高い抵抗値を意味し、実用的
には、体積抵抗率が１０12Ωcm以上程度で十分である。
高抵抗層の誘電率は、電界の効率から高い方が望まし
い。なお、この感光体上に帯電した電荷の対向電極部材
への注入は、対向電極部材を感光体に接触配置する場合
のみならず、これを感光体と近接させた場合にも装置振
動などによる両者の接触で発生する可能性がある。よっ
て高抵抗層を設けることはいずの場合にも有効である。An image forming apparatus using the method for charging a photoconductor of the present invention is constructed such that the electrode member for forming the electric field is arranged opposite to the surface of the photoconductor. It is desirable to provide a high resistance layer on the surface of the electrode member (hereinafter referred to as the counter electrode member) facing the surface of the photoconductor. here,
The high resistance means a resistance value that is high enough to prevent the charge charged on the photoconductor from being injected into the counter electrode member, and a volume resistivity of about 10 12 Ωcm or more is practically sufficient.
The dielectric constant of the high resistance layer is preferably high in view of electric field efficiency. The charge charged on the photoconductor is injected into the counter electrode member not only when the counter electrode member is placed in contact with the photoconductor, but also when the counter electrode member is brought close to the photoconductor due to vibration of the device or the like. May occur on contact with. Therefore, providing the high resistance layer is effective in all cases.

【００１１】また、感光体に作用する電界強度は、感光
体の支持体側の電極と、支持体側の電極と感光体とを挾
んで反対側の対向電極部材との距離で決まるので、この
対向電極部材は、感光体に作用する電界の安定化のた
め、感光体表面に対するある程度の位置精度をもって配
置することが必要である。支持体側の電極から感光体表
面までの距離はほぼ一定であるので、感光体の表面に対
して、電極部材の位置を決めれば良い。The strength of the electric field acting on the photoconductor is determined by the distance between the electrode on the support side of the photoconductor and the counter electrode member on the opposite side of the support side electrode and the photoconductor. The members need to be arranged with a certain degree of positional accuracy with respect to the surface of the photoconductor in order to stabilize the electric field acting on the photoconductor. Since the distance from the electrode on the support side to the surface of the photoconductor is substantially constant, the position of the electrode member may be determined with respect to the surface of the photoconductor.

【００１２】ここで、上記対向電極部材を感光体に接触
するように配設すれば、電極と感光体表面との位置関係
を固定し、感光体に作用する電界の状態を安定化させる
ことができる。このときいくらかの接触幅を持つことが
望ましい。そのために、電極側の高抵抗層を弾性体とす
る。あるいは感光体側が弾性を持つことも可能である。
この場合、高抵抗層材質としてはゴムが好敵である。ま
たこの高抵抗層材質としては発砲ウレタン等も使用でき
るが、この材質からなる表面の凹凸が大きいときは、表
面を平滑化するコ−ト層を持つことが好ましい。By disposing the counter electrode member so as to contact the photoconductor, the positional relationship between the electrode and the photoconductor surface can be fixed and the state of the electric field acting on the photoconductor can be stabilized. it can. It is then desirable to have some contact width. Therefore, the high resistance layer on the electrode side is made of an elastic body. Alternatively, the photoconductor side may have elasticity.
In this case, rubber is a good enemy for the material of the high resistance layer. Foamed urethane or the like can be used as the material of the high resistance layer, but if the surface of this material has large irregularities, it is preferable to have a coat layer for smoothing the surface.

【００１３】更に、感光体と電極部材の接触状態を安定
化させるという点で、対向電極部材は、感光体に対して
やや加圧状態に設置することが望ましい。加圧の大きさ
は、ゴムの形状・弾性率にもよるが、感光体と電極部材
との接触幅が０．２mmから１．０mm程度であるようにす
る。０．２mm以下であると、機械の振動等によるノイズ
によって、感光体と電極部材が非接触状態になる可能性
がある。また、１．０mm以上であると、接触部において
ずり力が大きく、両者の表面の劣化に悪影響を及ぼす。Further, from the viewpoint of stabilizing the contact state between the photoconductor and the electrode member, it is desirable that the counter electrode member is set in a slightly pressurized state with respect to the photoconductor. The amount of pressure applied depends on the shape and elastic modulus of the rubber, but the contact width between the photosensitive member and the electrode member should be about 0.2 mm to 1.0 mm. If it is 0.2 mm or less, noise due to mechanical vibration or the like may cause the photoconductor and the electrode member to be in a non-contact state. If it is 1.0 mm or more, the shearing force is large at the contact portion, which adversely affects the deterioration of the surfaces of both.

【００１４】そして、感光体と電極部材との対向領域
で、両者の接触部近傍に近接部も生じるような場合に
は、上記光照射は、相対位置関係がより確実で感光体に
作用する電界をより安定している接触部にて行うことが
望ましい。これにより、より安定した帯電（選択的な光
照射により静電潜像形成のための選択帯電を行うもので
は、潜像形成）が可能になる。Then, in the area where the photoconductor and the electrode member are opposed to each other, in the case where a proximity portion is also formed in the vicinity of the contact portion between the two, the above-mentioned light irradiation has a more reliable relative positional relationship and acts on the photoconductor. It is desirable to carry out at a more stable contact part. As a result, more stable charging (latent image formation in the case of performing selective charging for electrostatic latent image formation by selective light irradiation) becomes possible.

【００１５】また、上記対向電極部材は、導電性の電極
を軸として周囲に高抵抗層を付着させたローラ形状に形
成できる。このローラは、感光体の回転にともなって連
れ回るように支持することが望ましく。これによれば、
感光体と電極部材との間に摺擦力が作用せず摩耗を避け
ることができる。更に、連れ回りをスム−ズに行うため
に、対向電極部材と感光体とのいずれか少なくとも一方
にに弾性を持たせることが望ましい。Further, the counter electrode member can be formed in a roller shape with a high resistance layer attached to the periphery of the conductive electrode as an axis. It is desirable to support this roller so that it rotates with the rotation of the photoconductor. According to this
Since the rubbing force does not act between the photoconductor and the electrode member, wear can be avoided. Further, it is desirable that at least one of the counter electrode member and the photoconductor has elasticity in order to smoothly perform the accompanying rotation.

【００１６】また、上記対向電極部材を感光体表面に位
置決めするのには、感光体と対向電極との間にスペ−サ
を設け、これを感光体に突き当てる突き当て構造を採用
することもできる。このスペ−サは、感光体を傷つけな
い材質（樹脂など）や形状を採用することが望ましい。
なお、このスペーサを感光体層の一部分に接触させてギ
ャップを保持する場合、感光体層の摩耗、汚れによる位
置精度の悪化の心配がある。このような悪化を回避する
には、感光体層の表面ではなく、感光体層の表面には接
触せず、感光体層の位置を決めている部材にスペーサを
接触させれば良い。また、側板に対して感光体の位置を
設定する構成になっている場合、側板に対しての対向電
極部材の位置を決めれば良い。In order to position the counter electrode member on the surface of the photoconductor, it is also possible to employ a butting structure in which a spacer is provided between the photoconductor and the counter electrode and the spacer is abutted against the photoconductor. it can. This spacer is preferably made of a material (resin or the like) or shape that does not damage the photoreceptor.
When the spacer is brought into contact with a part of the photoconductor layer to maintain the gap, there is a concern that the photoconductor layer may be worn or soiled to deteriorate the positional accuracy. In order to avoid such deterioration, the spacer may be brought into contact with the member that determines the position of the photoconductor layer, not with the surface of the photoconductor layer, not with the surface of the photoconductor layer. Further, when the position of the photoconductor is set with respect to the side plate, the position of the counter electrode member with respect to the side plate may be determined.

【００１７】また、感光体を含むプロセス部がカ−トリ
ッジ構成になっているような場合は、カ−トリッジの構
造体に対して対向電極部材の位置を決める。例えば該構
造体の感光体に対向する内面自体に対向電極部材を設け
る。When the process portion including the photoconductor has a cartridge structure, the position of the counter electrode member is determined with respect to the structure of the cartridge. For example, a counter electrode member is provided on the inner surface itself of the structure facing the photoconductor.

【００１８】ここで、本発明の帯電方法では、感光体に
電界を作用させると共に光を照射することによって感光
体表面に現れた電荷は、電界の作用を外れると拡散を始
め、表面の電位は減衰し始める。従って、電界の作用を
外れてから帯電電荷を現像し顕像化するまでの時間はで
きるだけ短いことが望ましい。このためには、電界を作
用させる対向電極部材を光照射部に加えて該光照射部と
現像部の間にも配置し、光照射時と同じ方向の電界を作
用させるようにしても良い。例えば一つの対向電極で感
光体の光照射部から現像部までを覆うような構造にして
も良い。Here, in the charging method of the present invention, the electric charges appearing on the surface of the photoconductor by applying an electric field to the photoconductor and irradiating it with light start diffusion when the action of the electric field is deviated, and the potential of the surface changes. Begins to decay. Therefore, it is desirable that the time from when the action of the electric field is removed to when the charged charge is developed and visualized is as short as possible. For this purpose, the counter electrode member for applying an electric field may be arranged between the light irradiation unit and the developing unit in addition to the light irradiation unit, and the electric field in the same direction as that at the time of light irradiation may be applied. For example, the structure may be such that one counter electrode covers from the light irradiation part of the photoconductor to the developing part.

【００１９】なお、感光体に光照射する光照射手段とし
てＬＥＤヘッドを用いることができる。これはＬＥＤを
感光体軸方向に並べた状態のアレイに、レンズを組み合
わせたものであり潜像形成部の小型化が可能である。そ
して、感光体の表面側に対向電極部材を配置し、感光体
に電界を作用させつつこの対向電極部材側より光を照射
するのに、このＬＥＤヘッドを用いる場合、ＬＥＤヘッ
ドの感光体と対向する部分に透明の電極を形成して、こ
れを対向電極として利用し、この透明電極を通して感光
体に光を照射することが望ましい。この透明電極は、蒸
着ＩＴＯ等で形成できる。このようなＬＥＤヘッドは通
常焦点距離が短く、余裕度も広くないために感光体に対
して近接し、精度良く配置される。これは電極部材の設
定に対する要求と重なるため、ＬＥＤヘッドに対し一体
に対向電極を作れば、電極部材の単独の位置決め部材が
不要になり、構成が簡素化できる。また、正規現像の場
合、この透明電極には、帯電しようとする電位と逆極性
の電圧を印加するので、透明電極がトナーと同極性の電
位を持つ。このため、機械内の浮遊トナーのＬＥＤヘッ
ドへの付着も同時に防ぐことができる。An LED head can be used as the light irradiating means for irradiating the photosensitive member with light. This is a combination of a lens and an array in which LEDs are arranged in the axial direction of the photoconductor, and the latent image forming portion can be miniaturized. When the counter electrode member is disposed on the surface side of the photoconductor and the LED head is used for irradiating light from the counter electrode member side while applying an electric field to the photoconductor, the counter electrode member faces the photoconductor of the LED head. It is desirable that a transparent electrode is formed in the portion to be used, this is used as a counter electrode, and light is irradiated to the photoconductor through this transparent electrode. This transparent electrode can be formed of vapor-deposited ITO or the like. Since such an LED head usually has a short focal length and a wide margin, it is close to the photoconductor and is accurately arranged. Since this overlaps with the requirement for the setting of the electrode member, if the counter electrode is formed integrally with the LED head, a separate positioning member for the electrode member is not required, and the configuration can be simplified. Further, in the case of regular development, a voltage having the opposite polarity to the potential to be charged is applied to this transparent electrode, so that the transparent electrode has the same potential as the toner. Therefore, it is possible to prevent the floating toner in the machine from adhering to the LED head at the same time.

【００２０】また、上記感光体を繰り返し使用する場合
には、次回の潜像形成のために、感光体を初期状態に復
帰させる必要がある。この方法としては、単層型感光体
の場合、両極性のキャリア移動が可能であるため、帯電
部に光照射を行えば帯電の除去が可能である。すなわ
ち、この光照射により、既に帯電されている電荷と、基
体のアースされた電極との間に電界が生じているので、
光照射により、既に帯電されている電荷逆極性のキャリ
アが層中を移動し帯電電荷を除電できる。より積極的に
除電するため、帯電している極性と同極性のバイアスを
印加した電極を帯電部側に設けても良い。一方、積層が
他感光体の場合、キャリア輸送層中を移動するキャリア
は、正孔あるいは電子のどちらか一方であるため、光照
射のみによる除電はできない。よって、コロナ放電装置
を設けて交流を印加したり、導電性部材を感光体表面に
接触させて交流バイアスを印加したりすることにより除
電する。この導電性部材としては中抵抗の弾性ローラ
（例えばゴムローラ）が最適である。印加バイアスは交
流に代え、帯電極性と逆極性の直流バイアスを用いても
よういが、この場合逆極性の帯電過多になる恐れがある
ので交流が望ましい。 （以下、余白）When the photoconductor is repeatedly used, it is necessary to restore the photoconductor to the initial state for the next latent image formation. As for this method, in the case of a single-layer type photosensitive member, since carriers of both polarities can be moved, it is possible to remove the charge by irradiating the charging section with light. That is, because of this light irradiation, an electric field is generated between the already charged electric charge and the grounded electrode of the substrate,
By irradiation with light, already charged carriers of opposite polarity can move in the layer and eliminate the charged charges. An electrode to which a bias having the same polarity as the charged polarity is applied may be provided on the charging unit side for more positive charge removal. On the other hand, in the case where the layered structure is another photoreceptor, the carriers moving in the carrier transport layer are either holes or electrons, and therefore charge removal by light irradiation alone cannot be performed. Therefore, a corona discharge device is provided to apply an alternating current, or a conductive member is brought into contact with the surface of the photoconductor to apply an alternating current bias to remove electric charge. An elastic roller having a medium resistance (for example, a rubber roller) is optimal as the conductive member. The applied bias may be a direct current bias having a polarity opposite to the charging polarity instead of the alternating current, but in this case, an alternating current is preferable because there is a possibility of excessive charging of the opposite polarity. (Hereafter, margin)

【００２１】[0021]

【実施例】【Example】

〔実施例１〕以下、本発明の一実施例に係る画像形成装
置について説明する。図４（ａ）において、１７が感光
体、１８が対向電極、１９が図示しない光書込装置から
の照射光、２０が現像部、２１が転写部である。感光体
１７は通常のカールソンプロセスにおいて負極性帯電用
として用いられる積層型有機感光体であり、矢印の方向
に回転する。この感光体１７の表面に対向配置された電
極部材１８は、透明の基体２２上に透明電極２３を付着
させたものである。この透明基体２２は、アクリル製で
あるが他の樹脂あるいはガラス等でも良い。透明電極２
３はＩＴＯ（インジウムティンオキサイド）の蒸着膜や
酸化錫膜など、電圧を印加でき、かつ上記照射光に対し
て透明であればどのようなものでもよい。静電潜像形成
部において、対向電極１８の表面は感光体表面から５０
０μm離れている。この対向電極１８に−２．５ｋＶの
電圧が印加され、感光体１７の支持体の導体は接地され
ている。[Embodiment 1] An image forming apparatus according to an embodiment of the present invention will be described below. In FIG. 4A, 17 is a photoconductor, 18 is a counter electrode, 19 is irradiation light from an unillustrated optical writing device, 20 is a developing section, and 21 is a transfer section. The photoconductor 17 is a laminated organic photoconductor used for negative charging in the usual Carlson process, and rotates in the direction of the arrow. The electrode member 18 arranged so as to face the surface of the photoconductor 17 has a transparent substrate 23 and a transparent electrode 23 attached thereto. The transparent substrate 22 is made of acrylic, but other resin, glass, or the like may be used. Transparent electrode 2
3 may be any film such as a vapor deposition film of ITO (indium tin oxide) or a tin oxide film as long as it can apply a voltage and is transparent to the irradiation light. In the electrostatic latent image forming portion, the surface of the counter electrode 18 is 50
0 μm apart. A voltage of -2.5 kV is applied to the counter electrode 18, and the conductor of the support of the photoconductor 17 is grounded.

【００２２】以上の構成において、図示しない画像信号
処理部で処理された画像信号にしたがって変調された照
射光１９は、感光体１７に照射される。光により生じた
正孔と電子の対のうちの正孔が電界に引かれて感光体１
７の感光層中を移動する。このようにして、感光体表面
には画像信号に応じた静電潜像が形成される。感光体の
初期状態の帯電電位は約＋１５０Ｖ程度であり、形成さ
れた静電潜像は約＋６００Ｖ程度である。ここで、本実
施例の積層型有機感光体は正孔移動型であり、通常のカ
ールソンプロセスにおいては、外部から与えられるマイ
ナス帯電電荷により、負極性帯電するが、本実施例では
前述の電界下における光照射で正孔を移動させて表面を
プラスに帯電させる。このようにして形成された静電潜
像は、感光体１７の回転にともなって移動し、現像部２
０で着色トナーにより現像される。このトナーの極性は
マイナスであり、現像部２０で使用される現像バイアス
は非画像部電位と画像部電位との間の電位に設定する。
この実施例の場合には、約＋２００Ｖ程度である。感光
体１７上のトナー像は感光体１７の回転にともなって移
動し、転写部２１において紙に転写され、図示を省略し
た定着部を通過して排紙トレイなどに排出される。In the above structure, the photoconductor 17 is irradiated with the irradiation light 19 modulated according to the image signal processed by the image signal processing unit (not shown). The holes of the hole-electron pair generated by the light are attracted to the electric field, and the photoconductor 1
7 through the photosensitive layer. In this way, an electrostatic latent image corresponding to the image signal is formed on the surface of the photoconductor. The charging potential of the photoconductor in the initial state is about + 150V, and the electrostatic latent image formed is about + 600V. Here, the laminated organic photoreceptor of the present example is a hole transfer type, and in the usual Carlson process, it is negatively charged by the negatively charged charge given from the outside. The light irradiation in (1) moves holes to positively charge the surface. The electrostatic latent image formed in this way moves as the photoconductor 17 rotates, and the developing unit 2
0 develops with colored toner. The polarity of this toner is negative, and the developing bias used in the developing unit 20 is set to a potential between the non-image portion potential and the image portion potential.
In the case of this embodiment, it is about + 200V. The toner image on the photoconductor 17 moves along with the rotation of the photoconductor 17, is transferred to paper at the transfer unit 21, passes through a fixing unit (not shown), and is discharged to a paper discharge tray or the like.

【００２３】なお、図示を省略した光書込装置としては
レーザー書込装置やＬＥＤヘッドを用いたものを使用で
きる。このうち、ＬＥＤヘッドを用いたものを使用する
場合、このＬＥＤヘッドと透明電極２３を一体化しても
良い。図４（ｂ）はその構成例を示すものである。図
中、２４はＬＥＤアレイ、２５はセルフォーカスレンズ
（等倍結像レンズ）、２６はケ−シングである。透明電
極２７が感光体に対するＬＥＤの光射出側の面に設けら
れている。この透明電極２７に電圧を印加し、接地され
た感光体の支持体との間に電界を作用させると共に、Ｌ
ＥＤを点灯させ、静電潜像を感光体表面に形成する。通
常ＬＥＤを使用し、画像形成を行う場合と同様に、感光
体上にＬＥＤヘッドを設置することによって、電極に位
置精度も確保できる。As the optical writing device (not shown), a device using a laser writing device or an LED head can be used. Of these, when the one using the LED head is used, the LED head and the transparent electrode 23 may be integrated. FIG. 4B shows an example of the configuration. In the figure, 24 is an LED array, 25 is a cell focus lens (equal magnification imaging lens), and 26 is a casing. The transparent electrode 27 is provided on the surface of the light emitting side of the LED with respect to the photoconductor. A voltage is applied to the transparent electrode 27 to cause an electric field to act between the transparent electrode 27 and the grounded support of the photoconductor, and L
The ED is turned on to form an electrostatic latent image on the surface of the photoconductor. Similar to the case where an image is formed by using a normal LED, by installing an LED head on the photoconductor, the positional accuracy of the electrodes can be secured.

【００２４】上記感光体を繰り返し使用する場合には、
感光体を初期状態に復帰させるための例えば交流バイア
ス印加の中抵抗弾性ローラを、転写と潜像形成の間に設
ける。When the above photoreceptor is repeatedly used,
A medium resistance elastic roller for applying an AC bias, for example, for returning the photoconductor to the initial state is provided between the transfer and the latent image formation.

【００２５】〔実施例２〕本発明の他の実施例に係る画
像形成装置について説明する。本実施例の画像形成装置
は、感光体１７に支持体側から光を照射するものであ
る。図５（ａ）において、感光体２８はドラム状にされ
た感光体であり、図４（ａ）の装置におけると同様に、
その周囲には図示を省略した現像部や転写部が設けられ
ている。図中、２９が透明の支持体、３０が透明電極、
３１が感光層である。対向電極３２はロ−ラ形状で、感
光体２８に接触して感光体２８表面の移動にともなって
連れ回りする構成になっている。この対向電極ローラ３
２は電極としてのステンレス製の軸３３上にシリコ−ン
ゴム層３４を設けたものである。この軸３３には外部電
源３５より電圧が印加され、接地された感光体２８の支
持体側電極３０との間で電界を形成している。３６はＬ
ＥＤヘッドである。ＬＥＤヘッドから選択的に光が照射
され、発生した電荷は電界の作用で移動し、感光体表面
に正の電位を生じる。[Embodiment 2] An image forming apparatus according to another embodiment of the present invention will be described. The image forming apparatus of the present embodiment irradiates the photoconductor 17 with light from the support side. In FIG. 5A, the photoconductor 28 is a drum-shaped photoconductor, and as in the apparatus of FIG. 4A,
A developing portion and a transfer portion (not shown) are provided around the periphery. In the figure, 29 is a transparent support, 30 is a transparent electrode,
Reference numeral 31 is a photosensitive layer. The counter electrode 32 has a roller shape and is configured to come into contact with the photoconductor 28 and rotate along with the movement of the surface of the photoconductor 28. This counter electrode roller 3
Reference numeral 2 denotes a silicone rubber layer 34 provided on a stainless steel shaft 33 as an electrode. A voltage is applied to the shaft 33 from an external power source 35, and an electric field is formed between the shaft 33 and the support-side electrode 30 of the photoconductor 28 that is grounded. 36 is L
It is an ED head. Light is selectively emitted from the LED head, and the generated charges move due to the action of the electric field to generate a positive potential on the surface of the photoconductor.

【００２６】ここで、上記ステンレス製軸３３の径は８
mmであり、表面のシリコ−ンゴム層３４の厚さは、非接
触状態において１mmである。この軸３３に対して約１kg
wの力を感光体２８方向に加えており、感光体２８と電
極部材３２との接触幅は、約０．５mmである。軸３３は
ステンレス製に限らず、剛体の導電体であれば良い。表
面のコ−ト層３４はシリコ−ンゴムに限らず、ナイロン
等の絶縁膜であっても良い。Here, the diameter of the stainless steel shaft 33 is 8
mm, and the thickness of the silicone rubber layer 34 on the surface is 1 mm in the non-contact state. About 1kg for this shaft 33
The force of w is applied in the direction of the photoconductor 28, and the contact width between the photoconductor 28 and the electrode member 32 is about 0.5 mm. The shaft 33 is not limited to stainless steel and may be a rigid conductor. The surface coat layer 34 is not limited to silicone rubber, but may be an insulating film such as nylon.

【００２７】図５（ｂ），（ｃ）はそれぞれ対向電極ロ
ーラの他の構成例を示すものである。図５（ｂ）の例
は、ＳＵＳ製の軸３７上に順次、発砲ウレタン層３８と
ルミフロン層（フッ素化ウレタン樹脂である旭硝子社製
ルミフロン６１０Ｃからなる層）３９を設けたものであ
る。図５（ｃ）の例ではアルミ製の軸４０上にシリコ−
ン膜４１を設けたものである。いずれの例でも機能は同
じであるが、発砲ウレタン層など弾性層を持つ場合に
は、比較的広い感光体との接触幅を得られやすく、接触
の安定性の点で有利である。また、発砲性の材質を使用
する場合、感光体と接触する表面は比較的凹凸が大き
く、電界が不均一になる恐れがある。そのため、表面に
平滑な層を設けることが好ましい。更に、二層構成の場
合、導体の電極と感光体との距離が離れてしまい、印加
した電圧に対する感光体に作用する電界強度が小さくな
り効率が落ちるのを防止するため、下層は導電性を有
し、実質的に下層まで電極として機能するようにするこ
とが望ましい。5 (b) and 5 (c) show another example of the structure of the counter electrode roller. In the example of FIG. 5B, a foamed urethane layer 38 and a Lumiflon layer (a layer made of a Lumiflon 610C manufactured by Asahi Glass Co., Ltd., which is a fluorinated urethane resin) 39 are sequentially provided on a SUS shaft 37. In the example shown in FIG. 5 (c), the aluminum shaft 40 has a silicone
The film 41 is provided. Although the function is the same in any of the examples, when an elastic layer such as a foamed urethane layer is provided, it is easy to obtain a relatively wide contact width with the photoconductor, which is advantageous in terms of contact stability. In addition, when a foaming material is used, the surface in contact with the photoconductor has relatively large irregularities, and the electric field may become uneven. Therefore, it is preferable to provide a smooth layer on the surface. Furthermore, in the case of a two-layer structure, the conductive layer and the photoconductor are separated from each other, and the electric field strength acting on the photoconductor with respect to the applied voltage is reduced to prevent the efficiency from being lowered. It is desirable to have it so that it substantially functions as an electrode to the lower layer.

【００２８】以下の構成で、好ましい潜像が得られた。
すなわち、ＳＵＳ製の直径８mmの軸上に、体積抵抗率約
１０7Ωcmのウレタン弾性層を設け、その上に約２０μm
のルミフロン樹脂をコ−トしたローラを対向電極ローラ
として感光体に接触させ、−４００Ｖの電圧を印加し、
約＋３００Ｖ程度の電位の静電潜像が得られた。また、
直径１０mmのアルミ軸上に約１００μmのナイロンをコ
−トし、感光体に接触させた状態で、−４００Ｖ印加し
た場合、約２５０Ｖ程度の潜像電位が得られた。また、
ローラ形状の対向電極部材が感光体に連れ回りするた
め、感光体に接触しているにも拘らず、摩耗を少なく長
寿命であった。A preferable latent image was obtained with the following constitution.
That is, a urethane elastic layer having a volume resistivity of about 10 7 Ωcm is provided on a shaft made of SUS having a diameter of 8 mm, and about 20 μm is formed on the urethane elastic layer.
The roller coated with Lumiflon resin is used as a counter electrode roller and brought into contact with the photoconductor, and a voltage of -400 V is applied,
An electrostatic latent image with a potential of about +300 V was obtained. Also,
When nylon of about 100 μm was coated on an aluminum shaft having a diameter of 10 mm and applied at -400 V in a state of being in contact with the photoreceptor, a latent image potential of about 250 V was obtained. Also,
Since the roller-shaped counter electrode member rotates along with the photoconductor, it has little wear and has a long life despite being in contact with the photoconductor.

【００２９】なお、以上の各対向電極ローラは、感光体
に対して非接触に配置して使用することも可能である。
この場合には、表面を高抵抗にする必要は無く導体でも
良い。但し、表面が高抵抗、導体いずれの場合にも、感
光体との空隙幅は印加電圧との関係で放電が起こらない
ような値に設定する必要がある。It should be noted that each of the above-mentioned counter electrode rollers can also be arranged and used in a non-contact manner with the photoconductor.
In this case, the surface does not need to have a high resistance and may be a conductor. However, regardless of whether the surface has a high resistance or a conductor, it is necessary to set the gap width with respect to the photosensitive member to a value that does not cause discharge in relation to the applied voltage.

【００３０】〔変形例１〕次に、図６や図７を用いて上
記各実施例の画像形成装置における対向電極部材の変形
例について説明する。図６（ａ）は、対向電極部材をブ
レ−ド形状にした例を示すものである。この電極ブレ−
ド４２は透明アクリルゴム板４３における感光体４４に
接触しない側の面に電極としての酸化錫膜４５を付着さ
せたものである。この電極膜４５と感光体４４の導電性
支持体４６との間に外部電源４７により電界を形成す
る。光４８照射は、ブレ−ドと感光体との接触部Ｌにて
行う。このように接触部Ｌで光を照射することで、機械
の振動などにより図中上下方向に感光体表面の数百μm
程度のずれが生じた場合でも、電極ブレード４２の弾性
でこのずれ吸収して、電極ブレード４２と感光体表面と
の接触を良好に維持させ、安定した潜像形成が行えた。
これとは異なり、電極ブレード４２と感光体４４との非
接触部で光照射を行った場合には、変動による電界の変
化が大きく安定性に欠けた。[Modification 1] Next, a modification of the counter electrode member in the image forming apparatus of each of the above embodiments will be described with reference to FIGS. 6 and 7. FIG. 6A shows an example in which the counter electrode member has a blade shape. This electrode blur
The lead 42 is formed by attaching a tin oxide film 45 as an electrode to the surface of the transparent acrylic rubber plate 43 which is not in contact with the photosensitive member 44. An electric field is formed between the electrode film 45 and the conductive support 46 of the photoconductor 44 by an external power supply 47. The irradiation of the light 48 is performed at the contact portion L between the blade and the photoconductor. By irradiating light at the contact portion L in this manner, several hundred μm of the surface of the photoconductor is vertically moved in the drawing due to mechanical vibration or the like.
Even if a slight deviation occurs, the deviation is absorbed by the elasticity of the electrode blade 42, the contact between the electrode blade 42 and the surface of the photosensitive member is maintained well, and stable latent image formation can be performed.
In contrast to this, when light irradiation is performed in the non-contact portion between the electrode blade 42 and the photoconductor 44, the change in the electric field due to the change is large and the stability is lacking.

【００３１】〔変形例２〕図６（ｂ）は、板状の対向電
極部材４９をスペ−サ−５０を介して感光体に近接させ
た例である。このスペ−サ−５０は感光体（５１が感光
層、５２が導電性基体）の軸方向の両端の非画像部（潜
像形成に使用しない部分）で感光体に接している。スペ
−サ−５０の材質・形状は、感光体の表面を傷つけない
ものにすることが望ましく、例えば感光体表面が樹脂製
の場合は、スペーサー５０も樹脂製であることが望まし
い。例えばポリアセタ−ルを用いる。このスペ−サ−の
厚さを、感光体との接触状態における感光体表面との対
向電極部材４９表面とのギャップが約３００μmになる
ように設定しておき、外部電源５３により対向電極部材
４９（具体的にはその電極５４）に−１．５ｋＶ程度の
電圧を印加しながら、図示のように対向電極部材４９を
透過させて感光体に光５５を照射することで、約４００
Ｖ程度の静電潜像が得られた。[Modification 2] FIG. 6B shows an example in which the plate-shaped counter electrode member 49 is brought close to the photosensitive member via the spacer 50. The spacer 50 is in contact with the photoconductor (non-image portions (portions not used for latent image formation)) at both axial ends of the photoconductor (51 is a photosensitive layer and 52 is a conductive substrate). The spacer 50 is preferably made of a material and shape that does not damage the surface of the photoconductor. For example, when the photoconductor surface is made of resin, the spacer 50 is also preferably made of resin. For example, polyacetal is used. The thickness of this spacer is set so that the gap between the surface of the photoconductor and the surface of the counter electrode member 49 in contact with the photoconductor is about 300 μm, and the counter electrode member 49 is supplied by the external power source 53. By applying a voltage of about −1.5 kV to the electrode 54 (specifically, the electrode 54), the counter electrode member 49 is transmitted and the photoconductor 55 is irradiated with the light 55, as shown in FIG.
An electrostatic latent image of about V was obtained.

【００３２】なお、図示の例は、対向電極部材４９を透
過させて光を感光体に照射するため、透明支持体５６上
に透明電極５４を設けて対向電極部材４９を照射光に関
して透明にしているが、図５（ａ）の実施例のように感
光体の支持体側から光を照射する場合にも、同様のスペ
ーサー５０を用いた構造を使用できる。この場合には、
対向電極部材４９は透明である必要はなく、例えば電極
５４としは、金属製（例えば銅製）の電極を使用でき
る。In the illustrated example, since the photoconductor is irradiated with light through the counter electrode member 49, the transparent electrode 54 is provided on the transparent support 56 to make the counter electrode member 49 transparent with respect to the irradiation light. However, the same structure using the spacer 50 can also be used when light is irradiated from the support side of the photoconductor as in the embodiment of FIG. In this case,
The counter electrode member 49 does not need to be transparent, and for example, a metal (for example, copper) electrode can be used as the electrode 54.

【００３３】〔変形例３〕図７（ａ）は、感光体６３を
覆うように板状の対向電極部材５７を構成した例であ
る。この対向電極部材５７に電圧を印加し、接地された
感光体６３の透明な支持体５８上の透明電極５９との間
で外部電源６０により電界を作用させる。電界の作用下
でＬＥＤヘッド６１から光を照射し、感光体表面に静電
潜像を形成する。ここで、本発明の帯電方法は、光によ
って発生したキャリアが電界に引かれて感光体表面に現
れることで帯電しているもので、電界の作用が無くなっ
たときには逆方向に電荷が移動し、電位減衰が開始す
る。この減衰が現像部６２までの移動中に生じると、現
像するときの静電潜像のコントラストが、形成されたと
きのコントラストに比して低いくなってしまう。そこ
で、この例では、現像部６２近傍にまで対向電極部材５
７を延在させて電界を作用させ、潜像のコントラストを
保持できるようにしている。[Modification 3] FIG. 7A shows an example in which a plate-shaped counter electrode member 57 is formed so as to cover the photoconductor 63. A voltage is applied to the counter electrode member 57, and an external electric power source 60 causes an electric field to act between the counter electrode member 57 and the transparent electrode 59 on the transparent support 58 of the grounded photoreceptor 63. Light is emitted from the LED head 61 under the action of an electric field to form an electrostatic latent image on the surface of the photoconductor. Here, the charging method of the present invention is that the carriers generated by light are charged by being attracted to the electric field and appearing on the surface of the photoconductor, and when the action of the electric field disappears, the charges move in the opposite direction, Potential decay begins. If this attenuation occurs during the movement to the developing unit 62, the contrast of the electrostatic latent image at the time of development becomes lower than the contrast at the time of being formed. Therefore, in this example, the counter electrode member 5 is extended to the vicinity of the developing unit 62.
7 is extended to apply an electric field so that the contrast of the latent image can be maintained.

【００３４】以上の構成によれば、感光体６３を覆うよ
うな対向電極構成を採らなかった場合には、静電潜像の
電位は現像部に到達するまでに、一割から二割程度減衰
するのと異なり、現像部６１に到達するまでほとんど電
位減衰が生じないようにできた。また、例えば負極性の
静電潜像を、正極性のトナーで顕像化する場合、対向電
極部材５７に印加する電圧の極性は正であるため、対向
電極部材５７にトナーは付着しにくく性能保持の点から
も有利である。According to the above structure, when the counter electrode structure covering the photoconductor 63 is not adopted, the potential of the electrostatic latent image is attenuated by 10 to 20% before reaching the developing portion. Unlike this, it was possible to prevent the potential from being attenuated almost until it reached the developing section 61. Further, for example, when the negative electrostatic latent image is visualized with the positive toner, the polarity of the voltage applied to the counter electrode member 57 is positive, so that the toner hardly adheres to the counter electrode member 57 and the performance is improved. It is also advantageous in terms of retention.

【００３５】なお、図示の例は、透明感光体を用いてそ
の背面側に配置したＬＥＤ６０により光照射している
が、上記電位減衰を防止するため上記現像部６１近傍ま
で延在させた対向電極構造は、感光体の表面側から光照
射する例えば図４（ａ）の装置にも適用できる。In the illustrated example, the transparent photoconductor is used and light is emitted from the LED 60 arranged on the back side thereof. However, in order to prevent the potential attenuation, the counter electrode extending to the vicinity of the developing section 61 is provided. The structure can also be applied to, for example, the device of FIG. 4A in which light is irradiated from the surface side of the photoconductor.

【００３６】〔変形例４〕図７（ｂ）は、プロセス主要
部を一体的に構成し、カ−トリッジ状にした場合の例で
ある。図示の例では、感光体６４、現像部６５、クリ−
ニング部６６、感光体内ＬＥＤ６７、及び、対向電極部
材６８が、ケーシング６９内に設けられ、カートリッジ
になっている。この例でも対向電極部材６８に電圧を印
加し、感光体６４に電界を作用させ、ＬＥＤヘッド６７
で光照射し、静電潜像を形成する。そして、この例では
対向電極部材６８を感光体６４と対向するカ−トリッジ
のケーシング内面に設けている。図示の対向電極部材６
８は、前述の図７（ａ）の例におけるものと同一の機能
を発揮できるよう、現像部６５近傍まで延在している。[Modification 4] FIG. 7B shows an example in which the main part of the process is integrally formed into a cartridge shape. In the illustrated example, the photoconductor 64, the developing unit 65, and the clear
The inner part 66, the photoconductor LED 67, and the counter electrode member 68 are provided in a casing 69 to form a cartridge. In this example as well, a voltage is applied to the counter electrode member 68 to cause an electric field to act on the photoconductor 64, and the LED head 67
To irradiate light to form an electrostatic latent image. In this example, the counter electrode member 68 is provided on the inner surface of the casing of the cartridge facing the photoconductor 64. The illustrated counter electrode member 6
Reference numeral 8 extends to the vicinity of the developing unit 65 so that the same function as that in the example of FIG.

【００３７】以上の構成によれば、感光体６４が位置決
めされているカ−トリッジ構造体としてのケーシング６
９に対向電極部材６８を装着するので、対向電極部材６
８と感光体６４との距離の位置決めが容易になってい
る。According to the above construction, the casing 6 as the cartridge structure in which the photoconductor 64 is positioned.
Since the counter electrode member 68 is attached to the counter electrode 9,
The distance between the photosensitive drum 64 and the photosensitive member 64 can be easily positioned.

【００３８】なお、図示の例は、感光体６４に設けたＬ
ＥＤ６７により背面からの光照射行うものであるが、上
記ケーシング６９の所定箇所に照射光通過用の開口部や
照射光に関する透明部を形成するとともに、少なくとも
これに対応する対向電極部材６８部分を照射光に関して
透明に構成し、装置本体側に配置した光書込装置からの
光を、上記開口部又は透明部、及び、対向電極部材６８
を介して感光体表面に照射するようにしても良い。In the illustrated example, L provided on the photoconductor 64 is
Light is emitted from the back surface by the ED 67. An opening for passing the irradiation light and a transparent portion for the irradiation light are formed in a predetermined portion of the casing 69, and at least the corresponding counter electrode member 68 is irradiated. Light from the optical writing device that is transparent with respect to the light and is arranged on the device main body side is transmitted through the opening or the transparent portion and the counter electrode member 68.
The surface of the photoconductor may be irradiated with the light.

【００３９】[0039]

【発明の効果】請求項１あるいは２の感光体表面帯電方
法によれば、感光体に電界を作用させると共に光を照射
することにより感光体表面を帯電できるので、コロナ帯
電方式に比して小さな電圧を利用しオゾンをほとんど発
生させることなく感光体を帯電できる。According to the photosensitive member surface charging method of the first or second aspect, since the photosensitive member surface can be charged by applying an electric field to the photosensitive member and irradiating it with light, it is smaller than the corona charging method. The voltage can be used to charge the photoreceptor without generating ozone.

【００４０】また、一様な初期帯電を別に行うことな
く、電界作用下での選択的な光照射のみにより静電潜像
を形成することもできるので、カールソンプロセスに比
して静電潜像形成工程を簡略化できる。Since the electrostatic latent image can be formed only by selective light irradiation under the action of an electric field without separately performing uniform initial charging, the electrostatic latent image can be formed as compared with the Carlson process. The forming process can be simplified.

【００４１】特に、請求項２の感光体帯電方法によれ
ば、透明電極支持体上に感光体層が形成された感光体を
用い、上記光の照射を該感光体の支持体側から行うの
で、感光体として表面が無端移動するように駆動される
ドラム状あるはベルト状のものを使用する場合に、ドラ
ム状あるいはベルト状感光体の内部に光照射手段を配設
して装置全体の小型化を図ることができる。Particularly, according to the photoconductor charging method of the second aspect, since the photoconductor in which the photoconductor layer is formed on the transparent electrode support is used and the light irradiation is performed from the support side of the photoconductor, When using a drum-shaped or belt-shaped photosensitive member that is driven so that its surface moves endlessly, a light irradiation means is provided inside the drum-shaped or belt-shaped photosensitive member to reduce the size of the entire apparatus. Can be achieved.

【００４２】請求項３乃至１０の画像形成装置によれ
ば、請求項１の感光体表面帯電方法を用いるので、コロ
ナ帯電方式に比して小さな電圧を利用しオゾンをほとん
ど発生させることなく感光体を帯電できる。According to the image forming apparatus of claims 3 to 10, the method of charging the surface of the photosensitive member according to claim 1 is used. Therefore, a voltage smaller than that of the corona charging method is used and almost no ozone is generated. Can be charged.

【００４３】特に、請求項３乃至６の画像形成装置によ
れば、上記電界を形成するため感光体表面に対向配置し
た電極部材の表面に高抵抗層を設けて、感光体上に帯電
した電荷の対向電極部材への注入が起こらないようにす
るので、このような注入による静電潜像の不良発生を防
止できる。In particular, according to the image forming apparatus of claims 3 to 6, a high resistance layer is provided on the surface of the electrode member arranged to face the surface of the photosensitive member to form the electric field, and the charge charged on the photosensitive member is provided. Since the injection into the counter electrode member does not occur, it is possible to prevent the occurrence of a defect in the electrostatic latent image due to such injection.

【００４４】更に、請求項４の画像形成装置によれば、
上記電極部材が感光体表面に弾発的に接触し、ある程度
の機械の振動等がによっても両者の接触状態が維持され
るので、感光体と上記電極部材との距離に左右される感
光体に作用する電界の安定化を図ることができる。Further, according to the image forming apparatus of claim 4,
The electrode member elastically contacts the surface of the photoconductor, and the contact state between the two is maintained even if the mechanical vibration or the like occurs to some extent. It is possible to stabilize the electric field that acts.

【００４５】更に、請求項５の画像形成装置によれば、
請求項１の光照射を、互いの距離が一定で、上記電界が
安定している上記電極部材と感光体表面との接触部にて
行うので、安定した帯電を行うことができる。Further, according to the image forming apparatus of claim 5,
Since the light irradiation according to the first aspect is performed at the contact portion between the electrode member and the surface of the photosensitive member, where the distance between them is constant and the electric field is stable, stable charging can be performed.

【００４６】更に、請求項６の画像形成装置によれば、
周囲に高抵抗層を有するローラ形状の上記電極部材を、
感光体の回転にともなって連れ回らせるので、感光体と
電極部材との間に摺擦力が作用せず摩耗を避けることが
できる。Further, according to the image forming apparatus of claim 6,
The roller-shaped electrode member having a high resistance layer around the periphery,
Since the photoconductor is rotated along with the rotation of the photoconductor, the frictional force does not act between the photoconductor and the electrode member, so that abrasion can be avoided.

【００４７】また特に、請求項７の画像形成装置によれ
ば、上記電界を形成するため感光体表面に対向配置した
電極部材の、少なくとも上記光の照射がされる感光体部
分に対する相対位置を、突き当て構造により一定にでき
るので、上記電界が安定している上記電極部材と感光体
表面との接触部にて光の照射を行って安定した帯電を行
うことができる。In particular, according to the image forming apparatus of the seventh aspect, the relative position of the electrode member arranged facing the surface of the photoconductor for forming the electric field is at least relative to the photoconductor portion to which the light is irradiated. Since it can be made constant by the butting structure, stable charging can be performed by irradiating light at the contact portion between the electrode member where the electric field is stable and the surface of the photosensitive member.

【００４８】また特に、請求項８の画像形成装置によれ
ば、感光体が位置決めされているカ−トリッジ構造体の
感光体表面と対向する部分に上記電界を形成するための
電極部材を設けて、感光体と該電極部材とのの相対的な
位置決めを行っているので、両者の距離が一定になり、
該距離に左右される感光体に作用する電界の安定化を図
ることができる。Further, according to the image forming apparatus of the present invention, in particular, an electrode member for forming the electric field is provided at a portion of the cartridge structure, on which the photoconductor is positioned, facing the photoconductor surface. Since the relative positioning of the photoconductor and the electrode member is performed, the distance between the two becomes constant,
It is possible to stabilize the electric field acting on the photoconductor depending on the distance.

【００４９】また特に、請求項９の画像形成装置によれ
ば、光照射による帯電を行う帯電部から現像部近傍まで
の範囲で、感光体に対向するように設けた上記電界を形
成するための電極部材により、該帯電部で感光体表面に
現れた電荷が拡散して感光体表面の電位が減衰するのを
防止しながら、感光体表面が現像部まで移動できるよう
にしているので、該電荷の拡散の少ない静電潜像を現像
部で顕像化して良好な画像を得ることができる。Further, according to the image forming apparatus of the ninth aspect, in order to form the electric field provided so as to face the photoconductor in the range from the charging section for charging by light irradiation to the vicinity of the developing section. The electrode member prevents the charge appearing on the surface of the photoconductor from diffusing at the charging portion from attenuating the potential on the surface of the photoconductor, while allowing the surface of the photoconductor to move to the developing portion. It is possible to obtain a good image by visualizing the electrostatic latent image with less diffusion in the developing section.

【００５０】また特に、請求項１０の画像形成装置によ
れば、感光体に光照射する光照射手段としてＬＥＤヘッ
ドを用いるので、潜像形成部の小型化が可能である。ま
た、感光体に対して精度良く配置される該ＬＥＤヘッド
の露光光路上における感光体と対向する面に、該光に関
して透明な材質からなる上記電界を形成するための電極
部材を設けるので、該電極部材と感光体との距離も精度
よく保たれる。よって、感光体と上記電極部材との距離
に左右される感光体に作用する電界の安定化を図ること
ができる。なお、正規現像の場合、この透明電極には、
帯電しようとする電位と逆極性の電圧を印加するので、
透明電極がトナーと同極性の電位を持ち、機械内の浮遊
トナーのＬＥＤヘッドへの付着も同時に防ぐことができ
る。Further, according to the image forming apparatus of the tenth aspect, since the LED head is used as the light irradiating means for irradiating the photosensitive member with light, the size of the latent image forming portion can be reduced. Further, since an electrode member made of a material transparent with respect to the light is provided on the surface of the LED head, which is accurately arranged with respect to the photoconductor, on the exposure optical path facing the photoconductor, the electrode member is provided. The distance between the electrode member and the photoconductor can be maintained accurately. Therefore, it is possible to stabilize the electric field that acts on the photoconductor depending on the distance between the photoconductor and the electrode member. In the case of regular development, this transparent electrode
Since a voltage with the opposite polarity to the potential to be charged is applied,
Since the transparent electrode has the same electric potential as the toner, it is possible to prevent the floating toner in the machine from adhering to the LED head at the same time.

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

【図１】本発明の感光体表面帯電方法の一例を示す模式
図。FIG. 1 is a schematic view showing an example of a photosensitive member surface charging method of the present invention.

【図２】（ａ）及び（ｂ）は積層型感光体についての同
帯電方法の説明図。（ｃ）及び（ｄ）は積層型感光体に
ついての同帯電方法の説明図。FIG. 2A and FIG. 2B are explanatory views of the same charging method for a layered type photoconductor. (C) And (d) is explanatory drawing of the same charging method about a laminated type photoreceptor.

【図３】本発明の感光体表面帯電方法の他の例を示す模
式図。FIG. 3 is a schematic view showing another example of the photosensitive member surface charging method of the present invention.

【図４】（ａ）は本発明の実施例に係る画像形成装置の
概略構成を示す正面図。（ｂ）は同装置に適用できるＬ
ＥＤヘッドの斜視図。FIG. 4A is a front view showing a schematic configuration of an image forming apparatus according to an exemplary embodiment of the present invention. (B) is L applicable to the same device
The perspective view of an ED head.

【図５】（ａ）は本発明の他の実施例に係る画像形成装
置の一部の斜視図。（ｂ）及び（ｃ）はそれぞれ同装置
の対向電極ローラの構成例の説明図。FIG. 5A is a perspective view of a part of an image forming apparatus according to another embodiment of the present invention. (B) And (c) is explanatory drawing of the structural example of the counter electrode roller of the same apparatus, respectively.

【図６】（ａ）及び（ｂ）はそれぞれ対向電極部材の構
成例を示す斜視図。6A and 6B are perspective views showing a configuration example of a counter electrode member.

【図７】（ａ）及び（ｂ）はそれぞれ対向電極部材の他
の構成例を示す斜視図。7A and 7B are perspective views showing another configuration example of the counter electrode member.

【符号の説明】[Explanation of symbols]

１ 透明支持体 ２ 透明電極 ３ 導電性基体 ４ 感光体層 ５ 感光体 ６ 光 1 Transparent support 2 Transparent electrode 3 Conductive substrate 4 Photoconductor layer 5 Photoconductor 6 Light

フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ４１Ｊ 2/455 Ｇ０３Ｇ 21/16 Continuation of the front page (51) Int.Cl. 6 Identification number Office reference number FI technical display location B41J 2/455 G03G 21/16

Claims (10)

【特許請求の範囲】[Claims] 【請求項１】感光体に対しキャリアが移動可能な方向に
電界を作用させると共に光を照射し、感光体内で発生し
たキャリアを感光体表面に移動させることで、感光体表
面を帯電することを特徴とする感光体表面帯電方法。1. A surface of a photoconductor is charged by causing an electric field to act on the photoconductor in a direction in which the carrier can move and irradiating light to move the carrier generated in the photoconductor to the surface of the photoconductor. A characteristic method for charging the surface of a photoconductor. 【請求項２】透明電極支持体上に感光体層が形成された
感光体を用い、上記光の照射を該感光体の支持体側から
行うことを特徴とする請求項１の感光体表面帯電方法。2. A method for charging a surface of a photoconductor according to claim 1, wherein a photoconductor having a photoconductor layer formed on a transparent electrode support is used, and the irradiation of the light is performed from the support side of the photoconductor. . 【請求項３】請求項１の感光体表面帯電方法を用いる画
像形成装置であって、 上記電界を形成するための電極部材を感光体表面側に配
設し、かつ該電極部材の感光体に対向する表面に高抵抗
層を設けたことを特徴とする画像形成装置。3. An image forming apparatus using the photoconductor surface charging method according to claim 1, wherein an electrode member for forming the electric field is disposed on the photoconductor surface side, and the photoconductor of the electrode member is provided with the electrode member. An image forming apparatus characterized in that a high resistance layer is provided on opposing surfaces. 【請求項４】上記電極部材が感光体表面に弾発的に接触
するように構成したことを特徴とする請求項３の画像形
成装置。4. The image forming apparatus according to claim 3, wherein the electrode member is configured to elastically contact the surface of the photoconductor. 【請求項５】上記電極部材を感光体表面に接触させて設
け、請求項１の光照射を両者の接触部に行うよう構成し
たことを特徴とする請求項３の画像形成装置。5. The image forming apparatus according to claim 3, wherein the electrode member is provided in contact with the surface of the photoconductor, and the light irradiation according to claim 1 is performed on both contact portions. 【請求項６】上記帯電部材を、ローラ形状に構成し、か
つ上記高抵抗層を介して感光体表面に接して感光体の回
転に伴い連れ回るように設けたことを特徴とする請求項
３の画像形成装置。6. The charging member is formed in a roller shape and is provided so as to come into contact with the surface of the photoconductor through the high resistance layer so as to be rotated along with the rotation of the photoconductor. Image forming device. 【請求項７】請求項１の感光体表面帯電方法を用いる画
像形成装置であって、 上記電界を形成するための電極部材を感光体表面側に配
設し、かつ、少なくとも上記光の照射がされる感光体部
分に対する該電極部材の相対位置が、突き当て構造によ
り決まるよう構成したことを特徴とする画像形成装置。7. An image forming apparatus using the photoconductor surface charging method according to claim 1, wherein an electrode member for forming the electric field is disposed on the photoconductor surface side, and at least the light irradiation is performed. The image forming apparatus is configured such that the relative position of the electrode member with respect to the photosensitive member portion is determined by the butting structure. 【請求項８】請求項１の感光体表面帯電方法を用いる画
像形成装置であって、 感光体がそれを含むカ−トリッジ内に構成されて、感光
体に対向したカ−トリッジの構造体の感光体表面と対向
する部分に、上記電界を形成するための電極部材を設け
たことを特徴とする画像形成装置。8. An image forming apparatus using the photosensitive member surface charging method according to claim 1, wherein the photosensitive member is formed in a cartridge including the photosensitive member, and a structure of a cartridge facing the photosensitive member is provided. An image forming apparatus, wherein an electrode member for forming the electric field is provided in a portion facing the surface of the photoconductor. 【請求項９】請求項１の感光体表面帯電方法を用いる画
像形成装置であって、 光照射による帯電を行う帯電部に対して感光体表面の移
動方向下流側に、トナーを付着させる現像部を設け、か
つ、上記電界を形成するための電極部材を、該帯電部か
ら現像部近傍までの範囲で、感光体に対向するように設
けたことを特徴とする画像形成装置。9. An image forming apparatus using the method for charging the surface of a photosensitive member according to claim 1, wherein a developing unit for adhering toner on the downstream side in the moving direction of the surface of the photosensitive member with respect to the charging unit for charging by light irradiation. And an electrode member for forming the electric field is provided so as to face the photoconductor in a range from the charging section to the vicinity of the developing section. 【請求項１０】請求項１の感光体表面帯電方法を用いる
画像形成装置であって、 上記光を照射する手段としてＬＥＤヘッドを用い、か
つ、該ＬＥＤヘッドの露光光路上における感光体と対向
する面に、該光に関して透明な材質からなる上記電界を
形成するための電極部材を設けたことを特徴とする画像
形成装置。10. An image forming apparatus using the photoconductor surface charging method according to claim 1, wherein an LED head is used as a means for irradiating the light, and the LED head faces a photoconductor on an exposure optical path of the LED head. An image forming apparatus characterized in that an electrode member made of a material transparent to the light for forming the electric field is provided on the surface.
JP23960394A 1994-09-06 1994-09-06 Charging method for photoreceptor and image forming device Withdrawn JPH0876559A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP23960394A JPH0876559A (en) 1994-09-06 1994-09-06 Charging method for photoreceptor and image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP23960394A JPH0876559A (en) 1994-09-06 1994-09-06 Charging method for photoreceptor and image forming device

Publications (1)

Publication Number Publication Date
JPH0876559A true JPH0876559A (en) 1996-03-22

Family

ID=17047214

Family Applications (1)

Application Number Title Priority Date Filing Date
JP23960394A Withdrawn JPH0876559A (en) 1994-09-06 1994-09-06 Charging method for photoreceptor and image forming device

Country Status (1)

Country Link
JP (1) JPH0876559A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003065127A1 (en) * 2002-01-25 2003-08-07 Sharp Kabushiki Kaisha Charging system
US7710444B2 (en) 2005-02-09 2010-05-04 Seiko Epson Corporation Image forming apparatus for forming a latent image on an image carrier
JP2010197773A (en) * 2009-02-26 2010-09-09 Ricoh Co Ltd Image carrier, image-forming method, image forming apparatus, and process cartridge

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003065127A1 (en) * 2002-01-25 2003-08-07 Sharp Kabushiki Kaisha Charging system
US7015938B2 (en) 2002-01-25 2006-03-21 Sharp Kabushiki Kaisha Charging system
US7710444B2 (en) 2005-02-09 2010-05-04 Seiko Epson Corporation Image forming apparatus for forming a latent image on an image carrier
JP2010197773A (en) * 2009-02-26 2010-09-09 Ricoh Co Ltd Image carrier, image-forming method, image forming apparatus, and process cartridge

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