JPH0743984A - Electrostatic charging member, process cartridge and image forming device - Google Patents
Electrostatic charging member, process cartridge and image forming deviceInfo
- Publication number
- JPH0743984A JPH0743984A JP5208810A JP20881093A JPH0743984A JP H0743984 A JPH0743984 A JP H0743984A JP 5208810 A JP5208810 A JP 5208810A JP 20881093 A JP20881093 A JP 20881093A JP H0743984 A JPH0743984 A JP H0743984A
- Authority
- JP
- Japan
- Prior art keywords
- tube
- charging
- image
- foaming
- charging roller
- 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.)
- Granted
Links
Landscapes
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
- Electrophotography Configuration And Component (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、振動電圧（時間ととも
に電圧値が周期的に変化する電圧）が印加されるととも
に、像担持体に当接または近接されて該像担持体を帯電
する帯電部材、該帯電部材を備えたプロセスカートリッ
ジ、画像形成装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging which applies an oscillating voltage (a voltage whose voltage value changes periodically with time) and charges the image carrier by coming into contact with or in proximity to the image carrier. The present invention relates to a member, a process cartridge including the charging member, and an image forming apparatus.
【０００２】[0002]
【従来の技術】画像形成装置等の帯電装置において、接
触方式のものが知られている。この接触方式の帯電装置
は、電圧を印加した導電性の帯電部材を被帯電体として
の像担持体に当接させ、帯電部材から感光ドラムに直接
的に電荷を転移させることによって像担持体表面を所定
の電位に帯電するものである。このような接触帯電装置
は、従来から広く利用されている非接触方式のコロナ放
電装置に比べて、印加電圧の低減が可能で電源の簡略化
がれること、帯電過程で発生するオゾン量がごく微量で
あること、このためオゾン除去フィルター等をなくして
排気系の構成の簡便化がれること、メンテナンスフリー
であること、等の長所を有している。このため、接触帯
電方式の帯電装置は、電子写真装置（複写機、レーザビ
ームプリンタ）、静電記録装置等の画像形成装置におい
て、感光体、誘電体等の像担持体をはじめ、その他感光
ドラム（以下単に「感光ドラム」という。）を帯電処理
する手段としてコロナ放電装置に代わるものとして注目
され、また実用化されている。2. Description of the Related Art A contact type charging device is known as a charging device such as an image forming apparatus. In this contact type charging device, a conductive charging member to which a voltage is applied is brought into contact with an image carrier as a member to be charged, and the charge is directly transferred from the charging member to the photosensitive drum to thereby transfer the surface of the image carrier. Is charged to a predetermined potential. Such a contact charging device can reduce the applied voltage, simplify the power supply, and reduce the amount of ozone generated during the charging process as compared with the non-contact type corona discharge device which has been widely used in the past. It has a merit that it is a very small amount, that is, the structure of the exhaust system can be simplified by eliminating the ozone removal filter, and that it is maintenance-free. For this reason, the contact charging type charging device is used in an image forming apparatus such as an electrophotographic apparatus (copier, laser beam printer), electrostatic recording device, etc., including an image carrier such as a photoconductor and a dielectric, and other photosensitive drums. As a means for charging (hereinafter, simply referred to as "photosensitive drum"), it has attracted attention as a substitute for a corona discharge device and has been put into practical use.
【０００３】上述の接触帯電装置においては、感光ドラ
ム表面をむらなく均一に帯電処理するために、交流電圧
に直流電圧を重畳した振動電圧を導電性の接触帯電部材
に印加し、この帯電部材を感光ドラムに当接させて帯電
を行う帯電方式が知られている（例えば、特開始６３−
１４９６６９号公報）。In the above-mentioned contact charging device, in order to uniformly and uniformly charge the surface of the photosensitive drum, an oscillating voltage in which a DC voltage is superimposed on an AC voltage is applied to a conductive contact charging member, and this charging member is charged. A charging method is known in which charging is performed by bringing the photosensitive drum into contact with the photosensitive drum.
149669).
【０００４】しかし、上述の帯電方式においては、振動
電圧に起因する、帯電音と呼ばれる振動音が発生し、大
きな問題となっている。However, in the above-mentioned charging system, a vibration noise called a charging noise is generated due to the vibration voltage, which is a serious problem.
【０００５】この帯電音を軽減させる対策として、これ
まで硬めのソリッドであった帯電部材の弾性体を、非常
に柔軟な発泡部材によって構成することにより、帯電部
材と感光ドラムとの振動を抑えることができ、帯電音も
気にならないレベルまで軽減することが可能である。As a measure for reducing the charging noise, the elastic body of the charging member, which has been hard so far, is made of a very flexible foam member to suppress the vibration between the charging member and the photosensitive drum. It is possible to reduce the charging noise to a level that does not bother you.
【０００６】しかしながら、発泡部材を主構成部材とす
る帯電部材においては、発泡部材それ自体の硬度が低
く、また温度、湿度等の外部環境によってその硬度が大
きく変化するため、帯電部材は外部から力を受けたとき
に、その力によって永久変形が発生してしまい、画像上
に帯電不良等が現れるおそれがある。However, in a charging member having a foamed member as a main constituent member, the hardness of the foamed member itself is low, and the hardness thereof greatly changes depending on the external environment such as temperature and humidity. When receiving the force, permanent deformation may occur due to the force, and charging failure or the like may appear on the image.
【０００７】これを防止する対策として、発泡部材の外
周面を、発泡部材によりも硬度の高い抵抗層であるチュ
ーブ部材（以下単に「チューブ」という。）で被覆する
方法が考えられている。これにより帯電音を大きくする
ことなく、発泡部材が受ける外力を緩和させることがで
きる。さらに発泡部材は表面性に劣るため、表面性に優
れたチューブで覆うことにより、画像むら等の問題をも
解消することができる。As a measure to prevent this, a method of covering the outer peripheral surface of the foam member with a tube member (hereinafter simply referred to as "tube") which is a resistance layer having a hardness higher than that of the foam member has been considered. This makes it possible to reduce the external force applied to the foam member without increasing the charging noise. Further, since the foamed member has a poor surface property, the problem such as image unevenness can be solved by covering it with a tube having a good surface property.
【０００８】図７に、その一実施例を示す。同図中、１
は感光ドラム（像担持体）であり、例えば、矢印Ｒ１方
向に所定の周速度（プロセススピード）にて回転駆動さ
れるドラム型の電子写真感光体、静電記録誘電体等であ
る。FIG. 7 shows an embodiment thereof. 1 in the figure
Is a photosensitive drum (image bearing member), and is, for example, a drum type electrophotographic photosensitive member that is rotationally driven in the direction of arrow R1 at a predetermined peripheral speed (process speed), an electrostatic recording dielectric, or the like.
【０００９】２は接触帯電部材としての導電性の帯電ロ
ーラであり、芯金（支持部材）２ａとその外周に形成し
た弾性体２Ｂとからなる。この帯電ローラ２は芯金２ａ
の両端部をそれぞれ感光ドラム１に向けて付勢する加圧
ばね３によって、感光ドラム１表面に対して所定の押圧
力をもって圧接されており、感光ドラム１の矢印Ｒ１方
向の回転に伴って矢印Ｒ２方向に従動回転する。Reference numeral 2 denotes a conductive charging roller as a contact charging member, which comprises a cored bar (supporting member) 2a and an elastic body 2B formed on the outer periphery thereof. The charging roller 2 has a core metal 2a.
Are pressed against the surface of the photosensitive drum 1 with a predetermined pressing force by pressing springs 3 that urge both ends of the photosensitive drum 1 toward the photosensitive drum 1. It is driven to rotate in the R2 direction.
【００１０】４は帯電ローラ２に対する電圧印加用の電
源であり、帯電ローラ２は、この電源４により、芯金２
ａに接触させた接点板ばね（不図示）を介して所定の帯
電電圧が印加され、回転駆動されている感光ドラム１表
面を均一に帯電する。このときの所定の帯電電圧とは、
感光ドラム１の帯電開始電圧の２倍以上のピーク間電圧
Ｖｐｐを有する振動電圧Ｖａｃと直流電圧Ｖｄｃとを重
畳した重畳電圧（Ｖａｃ＋Ｖｄｃ）である。Reference numeral 4 denotes a power source for applying a voltage to the charging roller 2, and the charging roller 2 is driven by the power source 4 to make the core metal 2
A predetermined charging voltage is applied via a contact leaf spring (not shown) brought into contact with a to uniformly charge the surface of the photosensitive drum 1 that is being rotationally driven. The predetermined charging voltage at this time is
It is a superposed voltage (Vac + Vdc) obtained by superposing the oscillating voltage Vac having the peak-to-peak voltage Vpp that is at least twice the charging start voltage of the photosensitive drum 1 and the DC voltage Vdc.
【００１１】図８は、帯電ローラ２の構成を詳細に示す
縦断面図である。帯電ローラ２は、芯金２ａとその周囲
を囲繞する弾性体２Ｂとによって構成されている。この
弾性体２Ｂは、内側から順に積層した、カーボンなどの
導電性粉体を分散させたポリウレタン等の発泡部材２
ｂ、抵抗層としてのチューブ２ｃ、さらにその外周の導
電層２ｄ、中抵抗層２ｅ、保護層２ｆによって構成され
ている。この帯電ローラ２において、発泡部材２ｂをチ
ューブ２ｃで被覆する方法としては、図９に示すよう
に、先に原料としての例えば導電ゴムを発泡させた発泡
部材２ｂを作製し、それに芯金２ａを挿入される方法
や、図１０に示すように、チューブ２ｃの内側に芯金２
ａを立て、発泡部材２ｂの原料を芯金２ａに差し込み、
固定させた状態で発泡させて作製する方法等がある。し
かし、表面性、精度、コストの面を考慮すると、後者の
方が優れている。FIG. 8 is a vertical sectional view showing the structure of the charging roller 2 in detail. The charging roller 2 is composed of a core metal 2a and an elastic body 2B surrounding the core metal 2a. This elastic body 2B is a foamed member 2 made of polyurethane or the like in which conductive powder such as carbon is dispersed, which is sequentially laminated from the inside.
b, a tube 2c as a resistance layer, a conductive layer 2d on the outer periphery thereof, a medium resistance layer 2e, and a protective layer 2f. In this charging roller 2, as a method of covering the foaming member 2b with the tube 2c, as shown in FIG. 9, a foaming member 2b in which, for example, conductive rubber is foamed as a raw material is first prepared, and the core metal 2a is attached thereto. As shown in FIG. 10 and the insertion method, the core metal 2 is placed inside the tube 2c.
a, stand up, insert the raw material of the foam member 2b into the core metal 2a,
There is a method of foaming in a fixed state. However, the latter is superior in view of surface property, accuracy, and cost.
【００１２】上述の帯電ローラ２を備えた画像形成装置
の動作を図７を参照して簡単に説明すると、次の通りで
ある。The operation of the image forming apparatus provided with the above charging roller 2 will be briefly described with reference to FIG.
【００１３】感光ドラム１を矢印Ｒ１方向に回転駆動
し、帯電ローラ２を矢印Ｒ２方向に従動回転させる。電
源４により、芯金２ａ、弾性体２Ｂを介して感光ドラム
１表面を均一に帯電する。表面が均一に帯電された感光
ドラム１は、その後、表面に露光手段５の露光を受けて
静電潜像が形成される。この静電潜像は、現像装置６に
よってトナー（現像剤）が付着されてトナー像となり、
このトナー像は、不図示の搬送装置によって搬送された
転写材７に、転写装置８によって転写される。トナー像
が転写された転写材７は、その後、定着装置（不図示）
によってトナー像が固着され、最終的なコピーとして装
置本体外部に排出される。The photosensitive drum 1 is rotationally driven in the direction of arrow R1, and the charging roller 2 is driven to rotate in the direction of arrow R2. The power source 4 uniformly charges the surface of the photosensitive drum 1 via the core metal 2a and the elastic body 2B. The surface of the photosensitive drum 1 whose surface is uniformly charged is then exposed to the exposure means 5 to form an electrostatic latent image on the surface. Toner (developer) is attached to the electrostatic latent image by the developing device 6 to form a toner image,
This toner image is transferred by the transfer device 8 to the transfer material 7 which is transferred by a transfer device (not shown). The transfer material 7 on which the toner image is transferred is then fixed to a fixing device (not shown).
Then, the toner image is fixed and discharged as a final copy to the outside of the apparatus main body.
【００１４】一方、トナー像転写後の感光ドラム１は、
表面に残った残留トナーがクリーニング装置９によって
除去され、次の画像形成プロセスに供される。On the other hand, the photosensitive drum 1 after the toner image transfer is
The residual toner remaining on the surface is removed by the cleaning device 9 and is subjected to the next image forming process.
【００１５】[0015]
【発明が解決しようとする課題】しかしながら、上述の
従来の技術によると、チューブ２ｃの内側に芯金２ａを
立て、発泡部材２ｂの原料を芯金２ａに差し込み、固定
させた状態で発泡させて作製する方法において、次のよ
うな問題が発生した。However, according to the above-mentioned conventional technique, the core metal 2a is erected inside the tube 2c, the raw material of the foaming member 2b is inserted into the core metal 2a, and foamed in a fixed state. The following problems occurred in the manufacturing method.
【００１６】図１０に示すように、発泡部材２ｂの原料
をチューブ２ｃ内にて発泡させた場合、チューブの両端
開口部から外側に向かって発泡の圧力が逃げてしまうた
め、発泡部材２ｂは、長手方向中央部に比べて両端部の
発泡密度が低くなってしまう。この結果、帯電ローラ２
の感光ドラム１に対する当接圧が中央部と両端部とでは
異なったり、発泡部材２ｂの体積低効率が長手方向で不
均一になったりして、画像むらなどの問題が発生した。As shown in FIG. 10, when the raw material of the foaming member 2b is foamed in the tube 2c, the foaming pressure escapes outward from the openings at both ends of the tube, so that the foaming member 2b is The foaming densities at both ends are lower than those in the central part in the longitudinal direction. As a result, the charging roller 2
The contact pressure with respect to the photosensitive drum 1 is different between the central portion and the both end portions, and the low volume efficiency of the foaming member 2b becomes non-uniform in the longitudinal direction, so that problems such as image unevenness occur.
【００１７】そこで、本発明は、チューブの両端部に内
側に向かって（芯金に向けて）減縮するテーパ部を設け
ることによって、発泡部材の長手方向について、発泡密
度や体積低効率が均一になるようにした帯電部材、プロ
セスカートリッジ、画像形成装置を提供することを目的
とするものである。Therefore, according to the present invention, by providing taper portions which contract inwardly (toward the core metal) at both ends of the tube, the foaming density and volume low efficiency are made uniform in the longitudinal direction of the foaming member. It is an object of the present invention to provide a charging member, a process cartridge, and an image forming apparatus that are configured as described above.
【００１８】[0018]
【課題を解決するための手段】本発明は、上述事情に鑑
みてなされたものであって、支持部材によって保持され
た弾性体を像担持体に接触させ、前記支持部材に帯電電
圧を印加して前記弾性体を介して像担持体を帯電する帯
電部材において、前記弾性体が、前記支持部材によって
支持された発泡部材と、該発泡部材を囲繞するとともに
前記像担持体に直接または他層を介して接触する抵抗層
としてのチューブ部材とを備え、該チューブ部材は、長
手方向両端部にそれぞれ内側に向けて減縮するテーパ部
を有することを特徴とする帯電部材。The present invention has been made in view of the above circumstances, and an elastic body held by a supporting member is brought into contact with an image carrier to apply a charging voltage to the supporting member. In the charging member for charging the image carrier via the elastic body, the elastic body surrounds the foamed member supported by the support member and directly or on another layer on the image carrier. A charging member comprising: a tube member as a resistance layer that is in contact with the tube member via the tube member. The tube member has tapered portions at both ends in the longitudinal direction, which taper toward the inside.
【００１９】この場合、前記チューブ部材の表面に、複
数の３００μｍ以下の孔を設ける、または、前記チュー
ブ部材の内面を粗面化することができる。In this case, a plurality of holes of 300 μm or less can be provided on the surface of the tube member, or the inner surface of the tube member can be roughened.
【００２０】また、プロセスカートリッジは、少なくと
も、前記像担持体と、上述の帯電部材と、これら像担持
体及び帯電部材を一体的に収容するカートリッジ容器と
を備え、画像形成装置の装置本体に対して着脱自在に装
着することを特徴とする。Further, the process cartridge includes at least the image carrier, the above-mentioned charging member, and a cartridge container for accommodating the image carrier and the charging member in an integrated manner. The feature is that it is detachably attached.
【００２１】さらに、画像形成装置は、前記像担持体
と、上述の帯電部材と、前記像担持体を露光して静電潜
像を形成する露光手段と、該静電潜像にトナーを付着さ
せてトナー像を形成する現像装置と、該トナー像を転写
材に転写する転写装置とを備えることを特徴とする。Further, the image forming apparatus includes the image carrier, the above-mentioned charging member, exposing means for exposing the image carrier to form an electrostatic latent image, and toner attached to the electrostatic latent image. It is characterized in that it is provided with a developing device for forming a toner image by means of this and a transfer device for transferring the toner image onto a transfer material.
【００２２】画像形成装置は、また、上述のプロセスカ
ートリッジを着脱自在に装着するための装着手段を有す
るものであってもよい。The image forming apparatus may also have a mounting means for removably mounting the above process cartridge.
【００２３】[0023]
【作用】以上構成に基づき、チューブの両端部に内側に
向けて減縮するテーパ部を設けることによって、チュー
ブの両端開口部から外側に向かって発泡の圧力が逃げる
ことを抑え、長手方向全域にわたって、発泡部材を均一
に発泡させることができるので、長手方向についての発
泡密度や体積低効率を均一にすることができる。According to the above structure, by providing tapered portions on both ends of the tube that contract toward the inside, it is possible to prevent the foaming pressure from escaping from the openings at both ends of the tube to the outside, Since the foaming member can be uniformly foamed, the foaming density in the longitudinal direction and the low volume efficiency can be made uniform.
【００２４】[0024]
【実施例】以下、図面に沿って、本発明の実施例につい
て説明する。 〈実施例１〉図１は、本発明に係る帯電部材としての帯
電ローラ２の縦断面を示す模式図、また図２は一端側
の、芯金２ａに沿った方向の断面を示す模式図である。Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a schematic view showing a vertical section of a charging roller 2 as a charging member according to the present invention, and FIG. 2 is a schematic view showing a section of one end side in a direction along a cored bar 2a. is there.
【００２５】これらの図中、１は被帯電体（像担持体）
としての帯電極性がマイナスまたはプラスの回転式の感
光ドラムである。２は接触帯電部材としての帯電ローラ
であり、この帯電ローラ２は、支持部材としてのステン
レス等の金属でできた芯金２ａとその周囲を囲繞する弾
性体２Ｂとによって構成されている。弾性体２Ｂは、上
述の芯金２ａの外周に同心一体にローラ状に形成された
発泡部材（発泡層）２ｂと、この発泡部材２ｂの外周面
を囲繞するようにして被覆するチューブ２ｃと、チュー
ブ２ｃを覆う導電層２ｄと、導電層２ｄを覆う中抵抗層
と２ｅと、そしてさらに中抵抗層２ｅを覆う保護層２ｆ
とによって構成されている。In these figures, 1 is a member to be charged (image carrier)
Is a rotary type photosensitive drum having a negative or positive charging polarity. Reference numeral 2 denotes a charging roller as a contact charging member. The charging roller 2 is composed of a core metal 2a made of metal such as stainless steel as a supporting member and an elastic body 2B surrounding the core metal 2a. The elastic body 2B includes a foam member (foam layer) 2b which is concentrically and integrally formed on the outer periphery of the core metal 2a in the shape of a roller, and a tube 2c which covers the outer peripheral surface of the foam member 2b so as to surround it. The conductive layer 2d that covers the tube 2c, the medium resistance layer and 2e that covers the conductive layer 2d, and the protective layer 2f that further covers the middle resistance layer 2e.
It is composed of and.
【００２６】発泡部材２ｂは、例えば、ポリスチレン、
ポリオレフィン、ポリエステル、ポリウレタン、ポリア
ミド系等の発泡部材や、ＥＰＤＭやウレタンを発泡させ
た柔軟な部材に、カーボン、酸化錫などの導電性粉体を
分散させて体積抵抗率を低くした部材である。The foam member 2b is made of polystyrene, for example.
It is a member in which conductive powder such as carbon or tin oxide is dispersed in a foamed member made of polyolefin, polyester, polyurethane, polyamide or the like, or a flexible member made by foaming EPDM or urethane to have a low volume resistivity.
【００２７】チューブ２ｃは、ウレタン、ステンレスゴ
ム、ハイパロン等の熱可塑性エラストマーを用いてお
り、帯電ローラ２の全体の抵抗が適当な値になるよう
に、チューブ２ｃの抵抗値を決めればよい。The tube 2c is made of a thermoplastic elastomer such as urethane, stainless rubber, and Hypalon, and the resistance value of the tube 2c may be determined so that the overall resistance of the charging roller 2 becomes an appropriate value.
【００２８】上述の発泡部材２ｂは、本実施例では発泡
させたポリウレタンにカーボンを分散させている。２
ｂ′はこの発泡部材２ｂの気泡部（空気、窒素、アルゴ
ンガスなどの封入気泡）である。In the foaming member 2b described above, carbon is dispersed in foamed polyurethane in this embodiment. Two
Reference numeral b'denotes a bubble portion (filled bubble of air, nitrogen, argon gas, etc.) of the foam member 2b.
【００２９】本実施例における帯電ローラ２の具体的な
仕様は下記の通りである。The specific specifications of the charging roller 2 in this embodiment are as follows.
【００３０】芯金２ａ ；直径６ｍｍ、長さ２５０ｍ
ｍのステンレス丸棒 発泡部材２ｂ；カーボン分散の発泡エピクロルヒドリン
ゴム 比重量０．４ｇ／ｃｍ3 体積抵抗値１０3 Ω・cm 層厚２．６ｍｍ、長さ２３０ｍｍ チューブ２ｃ；ポリウレタン熱可塑性エラストマー 体積抵抗値１０7 Ω・cm 層厚２５０μｍ 導電層２ｄ ；ＥＰＤＭやウレタンに多量のカーボン、
酸化錫等の導電性粉体を分散させたもの 体積抵抗値１０5 Ω・cm 層厚１０μｍ 中抵抗層２ｅ；エピクロルヒドリンゴム 体積抵抗値１０9 Ω・cm 層厚１８０μｍ 保護層２ｆ ；Ｎ−メトキシメチル化ナイロン 体積抵抗値１０9 Ω・cm 層厚５μｍ 帯電ローラ２の重量７０ｇ、硬度４５°（アスカーＣ） 感光ドラム１に対する押圧力 総圧１０００ｇ 上述帯電ローラ２において、芯金２ａからチューブ２ｃ
へ電荷が一様に供給できずに、チューブ２ｃ表面上での
帯電量が不均一になるのを防止するため、チューブ２ｃ
の外周面に体積抵抗値の低い導電層２ｄを設けてある。
また、中抵抗層２ｅの外周面に設けた保護層２ｆは、感
光ドラム１の表層に対し相性の良い材料を使用すること
で、感光ドラム１、帯電ローラ２の表層の汚染を防ぐこ
とができる。Core metal 2a; diameter 6 mm, length 250 m
m Stainless round bar Foaming member 2b; Carbon-dispersed foamed epichlorohydrin rubber Specific weight 0.4 g / cm 3 Volume resistance value 10 3 Ω · cm Layer thickness 2.6 mm, Length 230 mm Tube 2c; Polyurethane thermoplastic elastomer Volume resistance value 10 7 Ω · cm Layer thickness 250 μm Conductive layer 2d; Large amount of carbon in EPDM and urethane,
Conductive powder such as tin oxide dispersed Volume resistance value 10 5 Ω · cm Layer thickness 10 μm Medium resistance layer 2e; epichlorohydrin rubber Volume resistance value 10 9 Ω · cm Layer thickness 180 μm Protective layer 2f; N-methoxymethyl Nylon nylon Volume resistance value 10 9 Ω · cm Layer thickness 5 μm Charging roller 2 weight 70 g, hardness 45 ° (Asker C) Total pressure 1000 g on the photosensitive drum 1 In the charging roller 2 described above, the core 2 a to the tube 2 c
In order to prevent the charge from being uniformly supplied to the tube 2c and the charge amount on the surface of the tube 2c from becoming uneven,
A conductive layer 2d having a low volume resistance value is provided on the outer peripheral surface of the.
The protective layer 2f provided on the outer peripheral surface of the medium resistance layer 2e can prevent the surface layer of the photosensitive drum 1 and the charging roller 2 from being contaminated by using a material having a good compatibility with the surface layer of the photosensitive drum 1. .
【００３１】本発明の特徴とするところは、図２に示す
ように、チューブ２ｃの長手方向両端部に、長手方向内
側に向けて減縮するテーパ部２ｃ′を設けたことである
（ただし図２には、一方のテーパ部２ｃ′のみを図
示。）。A feature of the present invention is that, as shown in FIG. 2, tapered portions 2c 'are provided at both ends in the longitudinal direction of the tube 2c so as to reduce inward in the longitudinal direction (however, in FIG. 2). Shows only one tapered portion 2c '.)
【００３２】テーパ部のないチューブ２ｃ内で発泡部材
２ｂの原料を発泡させた場合、発泡部材２ｂの発泡圧力
はチューブ２ｃの長手方向中央部に比べて両端部では著
しく低くなっていた。これは、チューブ２ｃの長手方向
中央部での発泡が閉ざされた空間内での発泡であるのに
対して、両端部ではチューブ２ｃの開口部から外側に向
かって発泡しようとする力が働くため、その分チューブ
２ｃの発泡圧力が低下するからである。発泡圧力が低い
状態で発泡した発泡部材２ｂは、内部に形成される気泡
の大きさが大きくなる傾向にあり、その結果、発泡部材
２ｂの硬度が小さくなったり体積低効率が大きくなった
りしてしまう。When the raw material of the foaming member 2b was foamed in the tube 2c having no taper portion, the foaming pressure of the foaming member 2b was remarkably lower at both end portions than the central portion in the longitudinal direction of the tube 2c. This is because the foaming at the central portion in the longitudinal direction of the tube 2c is the foaming in the closed space, whereas the force acting to foam outward from the opening of the tube 2c acts at both ends. This is because the foaming pressure of the tube 2c decreases accordingly. The foamed member 2b foamed in a state where the foaming pressure is low tends to have a large size of bubbles formed therein, and as a result, the foamed member 2b has a reduced hardness and a reduced volume efficiency. I will end up.
【００３３】チューブ２ｃの長手方向両端部にテーパ部
２ｃ′を設けると、チューブ２ｃの開口部が小さくなる
ので、発泡部材２ｂの原料が外側に逃げることを抑えら
れるとともに、テーパ部２ｃ′の内壁によって、長手方
向中央部に向かって発泡を押し戻そうとする力が生まれ
る。こうして発泡部材２ｂの原料は、長手方向両端部に
テーパ部２ｃ′を設けたチューブ２ｃ内で発泡させる
と、長手方向両端部にあっても長手方向中央部と同程度
の発泡圧力を得ることができ、発泡部材２ｂの内部に形
成される気泡の大きさが長手方向全域で均一になる。内
部に形成される気泡の大きさが均一な発泡部材２ｂは、
その硬度や体積低効率が均一である。こうした発泡部材
２ｂによって構成された帯電ローラ２を用いて感光ドラ
ム１を帯電することにより、感光ドラム１上の表面電位
が一様になり、その結果帯電むらのない良好な画像が得
られる。When the tapered portions 2c 'are provided at both ends in the longitudinal direction of the tube 2c, the opening of the tube 2c becomes smaller, so that the raw material of the foaming member 2b is prevented from escaping to the outside and the inner wall of the tapered portion 2c' is suppressed. This creates a force that pushes the foam back towards the longitudinal center. In this way, when the raw material of the foaming member 2b is foamed in the tube 2c having the tapered portions 2c 'at both ends in the longitudinal direction, even at both ends in the longitudinal direction, a foaming pressure similar to that in the central portion in the longitudinal direction can be obtained. Therefore, the size of the bubbles formed inside the foam member 2b becomes uniform in the entire longitudinal direction. The foam member 2b in which the size of the bubbles formed inside is uniform,
Its hardness and volume efficiency are uniform. By charging the photosensitive drum 1 with the charging roller 2 constituted by the foaming member 2b, the surface potential on the photosensitive drum 1 becomes uniform, and as a result, a good image without uneven charging can be obtained.
【００３４】以下に、テーパ部２ｃ′の大きさを変えた
ときの効果を調べた実験について述べる。実験結果は図
３にまとめる。ここで、テーパ部２ｃ′の大きさは、チ
ューブ２ｃの長手方向中央部での横断面積に対する端部
開口部の面積の比、及び感光ドラム１表面に対するテー
パ部２ｃ′の角度α（図２参照）で表し、効果について
は、チューブ２ｃの長手方向端部で発泡した発泡部材２
ｂの硬度と体積低効率、さらに画出しによる確認を示し
た。図３からわかるように、チューブ２ｃの長手方向両
端部の開口部の面積は長手方向中央部での横断面積に対
して９０％以下であればむらのない画像を得ることがで
き、好ましくは８０％以下にすることにより、発泡部材
２ｂの硬度、体積抵抗率が長手方向中央部とほぼ同じと
みなすことができ、より安定した帯電が可能となる。ま
た、感光ドラム１表面に対するテーパ部２ｃ′の角度α
については、５°以上であればむらのない画像を得るこ
とができ、好ましくは２０°以上にすることで、発泡部
材２ｂの硬度、体積抵抗率が長手方向中央部とほぼ同じ
とみなすことができ、より安定した帯電が可能となる。 〈実施例２〉以下に、本発明の実施例２を示す。接触帯
電装置の帯電ローラ２は、両端にテーパ部を有するチュ
ーブ内で発泡させて形成したものであることは、実施例
１の場合と同様である。本実施例の特徴は、図４に示す
ように、長手方向両端部にテーパ部２ｈ′を設けたチュ
ーブ２ｈ表面に微小な孔２ｇを複数穿設したところにあ
る。An experiment for investigating the effect of changing the size of the tapered portion 2c 'will be described below. The experimental results are summarized in FIG. Here, the size of the tapered portion 2c 'is the ratio of the area of the end opening to the cross-sectional area of the tube 2c at the center in the longitudinal direction, and the angle α of the tapered portion 2c' with respect to the surface of the photosensitive drum 1 (see FIG. 2). ), For the effect, the foam member 2 foamed at the longitudinal end of the tube 2c.
The hardness of b, low volumetric efficiency, and confirmation by image formation are shown. As can be seen from FIG. 3, if the area of the openings at both ends in the longitudinal direction of the tube 2c is 90% or less of the cross-sectional area at the central portion in the longitudinal direction, an even image can be obtained, and preferably 80. By setting the content to be equal to or less than%, it can be considered that the foaming member 2b has substantially the same hardness and volume resistivity as those in the central portion in the longitudinal direction, and more stable charging is possible. In addition, the angle α of the taper portion 2c ′ with respect to the surface of the photosensitive drum 1
With respect to the above, it is possible to obtain an even image if the angle is 5 ° or more, and it is possible to assume that the hardness and volume resistivity of the foam member 2b are substantially the same as those in the central portion in the longitudinal direction by setting the angle to 20 ° or more. As a result, more stable charging is possible. <Example 2> Example 2 of the present invention will be described below. As in the first embodiment, the charging roller 2 of the contact charging device is formed by foaming in a tube having tapered portions at both ends. As shown in FIG. 4, the present embodiment is characterized in that a plurality of minute holes 2g are formed on the surface of the tube 2h having the tapered portions 2h 'at both ends in the longitudinal direction.
【００３５】図４のように、長手方向両端部にテーパ部
２ｈ′を設けたチューブ２ｈ内で発泡部材２ｂの原料を
発泡させた場合、発泡部材２ｂとチューブ２ｈとの界面
に、逃げ道を失った空気が溜り、そのまま大きな気泡と
して残ってしまう。この帯電ローラ２が感光ドラム１と
当接し、感光ドラム１が回転した場合、クリーニング装
置をすり抜けてきた残留トナーが帯電ローラ２と感光ド
ラム１との間に入り込み、帯電ローラ２のチューブ２ｈ
内側で逃げ道を失った空気による大きな気泡のある部分
にこの残留トナーが溜りやすくなり、画像上に帯電不良
となって黒い斑点のようなものが現れてしまう。As shown in FIG. 4, when the raw material of the foaming member 2b is foamed in the tube 2h having the tapered portions 2h 'at both ends in the longitudinal direction, the escape route is lost at the interface between the foaming member 2b and the tube 2h. The air that collects remains as large bubbles. When the charging roller 2 comes into contact with the photosensitive drum 1 and the photosensitive drum 1 rotates, the residual toner that has slipped through the cleaning device enters between the charging roller 2 and the photosensitive drum 1, and the tube 2h of the charging roller 2
The residual toner is likely to accumulate in a portion having large air bubbles due to the air that has escaped from the inner side, resulting in poor charging on the image and black spots appear.
【００３６】本実施例の具体例として、長手方向両端部
にテーパ部２ｈ′を設けたチューブ２ｈの表面に長手方
向に１５個、周方向に６箇所の微小な孔２ｇをあけた。
孔２ｇの大きさは、直径２０μｍである。As a specific example of this embodiment, 15 minute holes 2g are formed in the longitudinal direction and 6 minute holes 2g are formed in the circumferential direction on the surface of a tube 2h having tapered portions 2h 'at both longitudinal ends.
The size of the hole 2g is 20 μm in diameter.
【００３７】以上のようなチューブ２ｈ内で発泡部材２
ｂを発泡させた場合には、チューブ２ｈの長手方向両端
部での発泡圧力を長手方向中央部と同等にする効果は損
なわずに、発泡部材２ｂとチューブ２ｈとの界面に溜っ
た空気を、チューブ２ｈの表面にあけられた微小な孔２
ｇから逃がすことが可能となった。発泡部材２ｂとチュ
ーブ２ｈとの界面に大きな気泡が形成されなくなったた
め、この帯電ローラ２を感光ドラム１に当接させ、回転
した場合にも残留トナーが溜ることなく、良好な画像が
得られるようになった。In the tube 2h as described above, the foam member 2
When b is foamed, the air accumulated at the interface between the foaming member 2b and the tube 2h is retained without impairing the effect of equalizing the foaming pressure at both longitudinal ends of the tube 2h. Microscopic holes 2 on the surface of tube 2h
It became possible to escape from g. Since large bubbles are no longer formed at the interface between the foaming member 2b and the tube 2h, even if the charging roller 2 is brought into contact with the photosensitive drum 1 and rotated, residual toner does not accumulate and a good image can be obtained. Became.
【００３８】孔２ｇの大きさについては、３５０μｍの
場合にはその部分での凹みが生じ、チューブ２ｈの外周
面を導電層２ｄ、中抵抗層２ｅ、保護層２ｆで覆ったと
しても、その凹みが消えないため帯電むらとなってしま
う。このため、孔２ｇの大きさは３００μｍ以下、好ま
しくは２００μｍ以下であることが望ましい。また、孔
２ｇの数については、チューブ２ｈの表面積で１０ｃｍ
2 当り１個の場合には、発泡部材２ｂとチューブ２ｈと
の界面に溜った空気の逃げ道が足りずに大きな気泡がで
きてしまった。逆に、１０ｃｍ2 当り３５０個の孔２ｇ
をあけると、相互に隣接する孔２ｇと孔２ｇとの間隔が
狭くなり、チューブ２ｈの外周面を導電層２ｄ、中抵抗
層２ｅ、保護層２ｆで覆ったとしても、表面の平滑性が
損なわれるため、帯電むらとなった。そこで、孔２ｇの
数としては、１０ｃｍ2 当り２個以上３００個以下、好
ましくは１０ｃｍ2 当り５個以上１００個以下であるこ
とが望ましい。 〈実施例３〉以下に、本発明の実施例３を示すが、接触
帯電装置の帯電ローラ２を、両端にテーパ部を有するチ
ューブ内で発泡部材２ｂを発泡させて形成したものであ
ることは、実施例１と同様である。本実施例の特徴は、
図５に示すように、チューブ２ｉの内面を予め粗してあ
るところにある。Regarding the size of the hole 2g, when the size is 350 μm, a dent is formed at that portion, and even if the outer peripheral surface of the tube 2h is covered with the conductive layer 2d, the medium resistance layer 2e, and the protective layer 2f, the dent is formed. Does not disappear, resulting in uneven charging. Therefore, it is desirable that the size of the hole 2g is 300 μm or less, preferably 200 μm or less. Also, regarding the number of holes 2g, the surface area of the tube 2h is 10 cm.
In the case of one per two, large air bubbles were formed because the escape route of the air accumulated at the interface between the foam member 2b and the tube 2h was insufficient. Conversely, 2 holes of 350 holes per 10 cm 2
When the holes are opened, the distance between the holes 2g adjacent to each other is narrowed, and even if the outer peripheral surface of the tube 2h is covered with the conductive layer 2d, the medium resistance layer 2e, and the protective layer 2f, the surface smoothness is impaired. As a result, it became unevenly charged. Therefore, as the number of holes 2 g, 10 cm 2 per two or more 300 or less, preferably 100 or less 2 per 5 or more 10 cm. <Embodiment 3> Hereinafter, Embodiment 3 of the present invention will be described. It is to be understood that the charging roller 2 of the contact charging device is formed by foaming the foaming member 2b in a tube having tapered portions at both ends. The same as in Example 1. The feature of this embodiment is that
As shown in FIG. 5, the inner surface of the tube 2i is preliminarily roughened.
【００３９】長手方向両端部にテーパ部を設けたチュー
ブ内で発泡部材２ｂを発泡させた場合、発泡部材２ｂと
チューブとの界面において逃げ道を失った空気が溜り、
そのまま大きな気泡として残ってしまう。この帯電ロー
ラ２が感光ドラム１と当接し、感光ドラム１が回転した
場合、クリーニング装置をすり抜けてきた残留トナー
が、帯電ローラ２と感光ドラム１との間に入り込み、帯
電ローラ２の内側で逃げ道を失った空気による大きな気
泡のある部分にこの残留トナーが溜りやすくなり、画像
上に帯電不良となって黒い斑点のようなものが現れてし
まう。When the foaming member 2b is foamed in the tube having the tapered portions at both ends in the longitudinal direction, the air which has lost the escape route is accumulated at the interface between the foaming member 2b and the tube.
It remains as a large bubble. When the charging roller 2 comes into contact with the photosensitive drum 1 and the photosensitive drum 1 rotates, the residual toner that has slipped through the cleaning device enters between the charging roller 2 and the photosensitive drum 1 and escapes inside the charging roller 2. The residual toner is likely to accumulate in a portion having large bubbles due to the lost air, resulting in poor charging on the image and black spots appearing.
【００４０】本実施例の具体例として、長手方向両端部
にテーパ部を設けたチューブ２ｉの内面にチューブ２ｉ
の長手方向に沿ったスジを付けた。スジの深さは、Ｒｚ
で２０μｍである。As a specific example of this embodiment, the tube 2i is provided on the inner surface of the tube 2i having tapered portions at both ends in the longitudinal direction.
Streaks along the longitudinal direction of the. The stripe depth is Rz
Is 20 μm.
【００４１】以上のようなチューブ２ｉ内で発泡部材２
ｂを発泡させた場合には、チューブ２ｉの長手方向両端
部での発泡圧力を長手方向中央部と同等にする効果は損
なわずに、発泡部材２ｂとチューブ２ｉとの界面に溜っ
た空気を、チューブ２ｉの内面に付けたスジを通して逃
がすことが可能となった。発泡部材２ｂとチューブ２ｈ
との界面に大きな気泡が形成されなくなったため、この
帯電ローラ２を感光ドラム１に当接させ、回転させた場
合にも残留トナーが溜ることなく、良好な画像が得られ
るようになった。In the tube 2i as described above, the foam member 2
When b is foamed, the air accumulated at the interface between the foaming member 2b and the tube 2i is retained without impairing the effect of making the foaming pressure at both longitudinal ends of the tube 2i equal to that at the central portion in the longitudinal direction. It became possible to escape through the streak attached to the inner surface of the tube 2i. Foam member 2b and tube 2h
Since no large bubbles are formed at the interface between the charging roller 2 and the photosensitive drum 1, the residual toner is not accumulated even when the charging roller 2 is brought into contact with the photosensitive drum 1 and rotated, and a good image can be obtained.
【００４２】スジの深さについては、Ｒｚが０．０５μ
ｍのときにはチューブ２ｉ内で発泡部材２ｂの原料を発
泡させるときに、発泡部材２ｂとチューブ２ｉとの界面
に溜った空気を十分に逃がすことができずに、大きな気
泡となって残ってしまう空気がある。逆に、Ｒｚが１５
０μｍのときには、帯電ローラ２の硬度が周方向で不均
一となり、その結果、帯電ローラ２を感光ドラム１に当
接させ、回転させたときに帯電むらを生じる。このた
め、スジの深さは、Ｒｚで０．１μｍ以上１２０μｍ以
下、好ましくは０．５μｍ以上１００μｍ以下であるこ
とが望ましい。Regarding the depth of the streak, Rz is 0.05 μm.
In the case of m, when foaming the raw material of the foaming member 2b in the tube 2i, the air accumulated at the interface between the foaming member 2b and the tube 2i cannot be sufficiently escaped, and remains as large bubbles. There is. On the contrary, Rz is 15
When the thickness is 0 μm, the hardness of the charging roller 2 becomes uneven in the circumferential direction, and as a result, uneven charging occurs when the charging roller 2 is brought into contact with the photosensitive drum 1 and rotated. For this reason, it is desirable that the depth of the streak is 0.1 μm or more and 120 μm or less, preferably 0.5 μm or more and 100 μm or less in Rz.
【００４３】なお、チューブ２ｉの内面をすことは、発
泡部材２ｂとチューブ２ｉとの界面に溜った空気を逃が
すことが目的であり、チューブ２ｉの長手方向に沿った
スジ以外に、ランダムにすことでも同様の効果が得られ
た。 〈実施例４〉図６を参照して、実施例４を説明する。The purpose of cleaning the inner surface of the tube 2i is to allow the air accumulated at the interface between the foam member 2b and the tube 2i to escape, and in addition to the streaks along the longitudinal direction of the tube 2i, random cleaning is performed. The same effect was obtained with this. <Fourth Embodiment> A fourth embodiment will be described with reference to FIG.
【００４４】本実施例は、実施例１ないし実施例３のい
ずれかで説明した接触式の帯電部材もしくは帯電装置を
像担持体の帯電手段として用いている画像形成装置のプ
ロセスカートリッジである。The present embodiment is a process cartridge of an image forming apparatus using the contact type charging member or the charging device described in any of the first to third embodiments as a charging means of the image carrier.
【００４５】本実施例のプロセスカートリッジは、像担
持体としてのドラム状の電子写真感光体（感光ドラム）
１、接触帯電部材としての帯電ローラ２、現像装置６、
クリーニング装置９の４つのプロセス機器をカートリッ
ジ容器Ｃに一体的に組み込んで構成されている。また、
プロセスカートリッジの装着先となる画像形成装置の装
置本体には、プロセスカートリッジを着脱自在に装着す
るための装着手段が設けられている（不図示）。The process cartridge of this embodiment is a drum-shaped electrophotographic photosensitive member (photosensitive drum) as an image bearing member.
1, a charging roller 2 as a contact charging member, a developing device 6,
The four process devices of the cleaning device 9 are integrally incorporated in the cartridge container C. Also,
The apparatus main body of the image forming apparatus to which the process cartridge is mounted is provided with mounting means for mounting the process cartridge in a detachable manner (not shown).
【００４６】帯電ローラ２は実施例１ないし実施例３に
て説明したものを使用することができる。As the charging roller 2, those described in Embodiments 1 to 3 can be used.
【００４７】現像装置６において、６０は現像スリー
ブ、６１はトナー（現像剤）Ｔの収容容器、６２は収容
容器６１内のトナー攪拌棒であり、トナーＴを攪拌する
とともに現像スリーブ６０に向けて送り出す。６３は現
像スリーブ６０上にトナーＴを均一な厚さにコートする
ための現像ブレードである。In the developing device 6, 60 is a developing sleeve, 61 is a container for storing toner (developer) T, and 62 is a toner stirring rod in the storing container 61. The toner T is stirred and is directed toward the developing sleeve 60. Send out. Reference numeral 63 is a developing blade for coating the developing sleeve 60 with the toner T to a uniform thickness.
【００４８】クリーニング装置９においては、９０はク
リーニングブレード、９１はクリーニングブレード９０
にて回収されたトナーＴを溜めるトナー溜めである。In the cleaning device 9, 90 is a cleaning blade, and 91 is a cleaning blade 90.
It is a toner reservoir for accumulating the toner T collected in.
【００４９】１１はプロセスカートリッジのドラムシャ
ッターであり、実線示の閉じ状態から点線にて示すよう
に開き状態に開閉自在である。ドラムシャッター１１
は、プロセスカートリッジを画像形成装置の装置本体
（不図示）から取り出した状態においては実線示の閉じ
状態にあり、感光ドラム１の外部露出部分面を隠蔽して
感光ドラム１表面を保護している。Reference numeral 11 denotes a drum shutter of the process cartridge, which can be opened and closed freely from a closed state shown by a solid line to an opened state as shown by a dotted line. Drum shutter 11
Is in the closed state shown by the solid line when the process cartridge is taken out from the apparatus main body (not shown) of the image forming apparatus, and the surface of the photosensitive drum 1 that is exposed to the outside is concealed to protect the surface of the photosensitive drum 1. .
【００５０】プロセスカートリッジを装置本体に接着す
るときは、ドラムシャッター１１を点線のような開き状
態にする、あるいはプロセスカートリッジの装着過程で
ドラムシャッター１１が自動的に開き動作し、プロセス
カートリッジが正規に装着されると、感光ドラム１の外
部露出部分面が画像形成装置本体側の転写ローラ（転写
装置、図７参照）８に圧接した状態になる。When the process cartridge is adhered to the main body of the apparatus, the drum shutter 11 is opened as shown by the dotted line, or the drum shutter 11 is automatically opened during the mounting process of the process cartridge so that the process cartridge is properly opened. When mounted, the externally exposed portion surface of the photosensitive drum 1 is in pressure contact with the transfer roller (transfer device, see FIG. 7) 8 on the image forming apparatus main body side.
【００５１】またプロセスカートリッジと装置本体とが
機械的、電気的にカップリングして、装置本体側の駆動
機構でプロセスカートリッジ側の感光ドラム１、現像ス
リーブ６０、攪拌棒６２等の駆動が可能となり、また装
置本体側の電気回路によりプロセスカートリッジ側の帯
電ローラ２への帯電バイアスの印加、現像スリーブ６０
への現像バイアスの印加等が可能となり、画像形成動作
を実行できる状態になる。Further, the process cartridge and the apparatus main body are mechanically and electrically coupled to each other, so that the drive mechanism on the apparatus main body side can drive the photosensitive drum 1, the developing sleeve 60, the stirring rod 62 and the like on the process cartridge side. The application of a charging bias to the charging roller 2 on the process cartridge side by the electric circuit on the apparatus main body side, the developing sleeve 60
A developing bias can be applied to the image forming apparatus, and the image forming operation can be executed.
【００５２】１２はプロセスカートリッジのクリーニン
グ装置９と現像装置６との間に設けた露出用窓であり、
装置本体側のレーザスキャナー（不図示）からの出力レ
ーザ光（露光手段）５が、この露出用窓１２を通過して
プロセスカートリッジ内に入光して、感光ドラム１表面
が走査露光される。Reference numeral 12 is an exposure window provided between the cleaning device 9 of the process cartridge and the developing device 6,
Output laser light (exposure means) 5 from a laser scanner (not shown) on the apparatus main body side passes through the exposure window 12 and enters the process cartridge, and the surface of the photosensitive drum 1 is scanned and exposed.
【００５３】帯電ローラ２は前述したように、チューブ
の両端部に、内側に向けて減縮するテーパ部を設けるこ
とによって、帯電不良のない高品位な画質が得られるプ
ロセスカートリッジを構成することが可能である。As described above, the charging roller 2 is provided with a taper portion which is inwardly contracted at both ends of the tube, so that a process cartridge capable of obtaining a high quality image without charging failure can be constructed. Is.
【００５４】[0054]
【発明の効果】以上説明したように、本発明によると、
帯電部材のチューブの長手方向両端部に、内側に向かっ
て減縮するテーパ部を設けることにより、発泡部材をチ
ューブ内で発泡させたときに、発泡の圧力が長手方向両
端部の開口部から外側に逃げることを防止することがで
きるので、帯電部材は長手方向の全域にわたって、発泡
部材の硬度や体積抵抗率が均一となり、その結果、帯電
むらによる画像むらのない良好な画像を得ることが可能
となった。As described above, according to the present invention,
By providing taper portions that contract toward the inner side at both ends of the tube of the charging member in the longitudinal direction, when the foaming member is foamed in the tube, the foaming pressure is outward from the openings at both ends in the longitudinal direction. Since it is possible to prevent escape, the charging member has uniform hardness and volume resistivity of the foaming member over the entire area in the longitudinal direction, and as a result, it is possible to obtain a good image without image unevenness due to uneven charging. became.
【図１】実施例１の帯電部材の縦断面を示す模式図。FIG. 1 is a schematic diagram illustrating a vertical cross section of a charging member according to a first exemplary embodiment.
【図２】同じく帯電部材の端部近傍の、芯金方向の断面
を示す模式図。FIG. 2 is a schematic view showing a cross section in the core bar direction in the vicinity of the end of the charging member.
【図３】同じくテーパ部の大きさ及び角度と、硬度及び
体積抵抗率との関係を示す図。FIG. 3 is a diagram showing the relationship between the size and angle of the taper portion and the hardness and volume resistivity.
【図４】実施例２の帯電部材の端部近傍の、芯金方向の
断面を示す模式図。FIG. 4 is a schematic diagram showing a cross section in the core bar direction in the vicinity of an end portion of a charging member of Example 2.
【図５】実施例３の帯電部材の縦断面を示す模式図。FIG. 5 is a schematic view showing a vertical cross section of a charging member of Example 3.
【図６】実施例４のプロセスカートリッジの構成を示す
縦断面。FIG. 6 is a vertical cross-sectional view showing the structure of a process cartridge of Example 4.
【図７】従来の画像形成装置の感光ドラム近傍を示す模
式図。FIG. 7 is a schematic diagram showing the vicinity of a photosensitive drum of a conventional image forming apparatus.
【図８】従来の帯電ローラの構成を示す縦断面図。FIG. 8 is a vertical cross-sectional view showing the configuration of a conventional charging roller.
【図９】帯電ローラの作製方法を示す図。FIG. 9 is a diagram showing a method of manufacturing a charging roller.
【図１０】帯電ローラの他の作製方法を示す図。FIG. 10 is a diagram showing another method of manufacturing the charging roller.
１ 像担持体（被帯電体、感光ドラム） ２ 帯電部材（帯電ローラ） ２Ｂ 弾性体 ２ａ 支持部材（芯金） ２ｂ 発泡部材（弾性体） ２ｂ′ 気泡部 ２ｃ チューブ部材（チューブ） ２ｃ′ テーパ部 ２ｄ 導電層 ２ｅ 中抵抗層 ２ｆ 保護層 ２ｇ 孔 ２ｈ チューブ部材（チューブ） ２ｉ チューブ部材（チューブ） ３ 加圧ばね ４ 電源 ５ 露光手段（出力レーザ光） ６ 現像装置 ７ 転写材 ８ 転写装置 ９ クリーニング装置 Ｃ カートリッジ容器 1 image carrier (charged member, photosensitive drum) 2 charging member (charging roller) 2B elastic body 2a supporting member (core metal) 2b foaming member (elastic body) 2b 'bubble portion 2c tube member (tube) 2c' taper portion 2d conductive layer 2e medium resistance layer 2f protective layer 2g hole 2h tube member (tube) 2i tube member (tube) 3 pressure spring 4 power supply 5 exposure means (output laser light) 6 developing device 7 transfer material 8 transfer device 9 cleaning device C cartridge container
───────────────────────────────────────────────────── フロントページの続き (72)発明者 諏訪 貢一 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 居波 聡 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 尾島 磨佐基 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 佐野 哲也 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Koichi Suwa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Satoshi Inami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masaki Ojima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tetsuya Sano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation
Claims (6)
担持体に接触させ、前記支持部材に帯電電圧を印加して
前記弾性体を介して像担持体を帯電する帯電部材におい
て、 前記弾性体が、前記支持部材によって支持された発泡部
材と、 該発泡部材を囲繞するとともに前記像担持体に直接また
は他層を介して接触する抵抗層としてのチューブ部材と
を備え、 該チューブ部材は、長手方向両端部にそれぞれ内側に向
けて減縮するテーパ部を有する、 ことを特徴とする帯電部材。1. A charging member for bringing an elastic body held by a supporting member into contact with an image carrier and applying a charging voltage to the supporting member to charge the image carrier through the elastic body, wherein the elastic body is used. Includes a foam member supported by the support member, and a tube member surrounding the foam member and serving as a resistance layer that is in contact with the image carrier directly or through another layer, and the tube member has a longitudinal direction. A charging member characterized in that it has taper portions that contract toward the inside at both ends in the direction.
０μｍ以下の孔を設ける、 ことを特徴とする請求項１記載の帯電部材。2. A plurality of 30 is provided on the surface of the tube member.
The charging member according to claim 1, wherein a hole having a diameter of 0 μm or less is provided.
材。3. The charging member according to claim 1, wherein the inner surface of the tube member is roughened.
リッジ容器とを備え、 画像形成装置の装置本体に対して着脱自在に装着する、 ことを特徴とするプロセスカートリッジ。4. An image forming apparatus comprising at least the image carrier, the charging member according to claim 1, and a cartridge container that integrally houses the image carrier and the charging member. A process cartridge that is detachably attached to the main body of the apparatus.
と、 該静電潜像にトナーを付着させてトナー像を形成する現
像装置と、 該トナー像を転写材に転写する転写装置とを備える、 ことを特徴とする画像形成装置。5. The image carrier, the charging member according to claim 1, exposure means for exposing the image carrier to form an electrostatic latent image, and the electrostatic latent image. An image forming apparatus comprising: a developing device that adheres toner to an image to form a toner image; and a transfer device that transfers the toner image onto a transfer material.
着脱自在に装着するための装着手段を有する、 ことを特徴とする画像形成装置。6. An image forming apparatus, comprising: mounting means for detachably mounting the process cartridge according to claim 4.
Priority Applications (11)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05208810A JP3080125B2 (en) | 1993-07-30 | 1993-07-30 | Charging member, process cartridge, and image forming apparatus |
| EP98200185A EP0843231B1 (en) | 1993-07-30 | 1994-08-01 | Charging member, charging device and process cartridge detachably mountable to image forming apparatus |
| DE69428922T DE69428922T2 (en) | 1993-07-30 | 1994-08-01 | Charging part, charging device and process cassette which can be removed from an image-forming device |
| EP98200183A EP0840176B1 (en) | 1993-07-30 | 1994-08-01 | Charging member, charging device and process cartridge detachably mountable to image forming apparatus |
| EP94305709A EP0636949B1 (en) | 1993-07-30 | 1994-08-01 | Charging member, charging device and process cartridge detachably mountable to image forming apparatus |
| DE69428924T DE69428924T2 (en) | 1993-07-30 | 1994-08-01 | Charging part, charging device and process cassette removable from an image forming device |
| DE69414047T DE69414047T2 (en) | 1993-07-30 | 1994-08-01 | Charging part, charging device and process cassette removable from an image forming device |
| US08/629,081 US5765077A (en) | 1993-07-30 | 1996-04-08 | Charging member, charging device and process cartridge detachably mountable to image forming apparatus |
| HK98111775A HK1010583A1 (en) | 1993-07-30 | 1998-11-06 | Charging member, charging device and process cartridge detachably mountable to image forming apparatus |
| HK98112093A HK1010921A1 (en) | 1993-07-30 | 1998-11-17 | Charging member, charging device and process cartridge detrachably mountable to image forming apparatus |
| HK98112860A HK1011756A1 (en) | 1993-07-30 | 1998-12-05 | Charging member charging device and process cartridge detachably mountable to image forming apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05208810A JP3080125B2 (en) | 1993-07-30 | 1993-07-30 | Charging member, process cartridge, and image forming apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0743984A true JPH0743984A (en) | 1995-02-14 |
| JP3080125B2 JP3080125B2 (en) | 2000-08-21 |
Family
ID=16562503
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05208810A Expired - Lifetime JP3080125B2 (en) | 1993-07-30 | 1993-07-30 | Charging member, process cartridge, and image forming apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3080125B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0716354A2 (en) * | 1994-12-07 | 1996-06-12 | Canon Kabushiki Kaisha | Reconditioning method for charging roller |
| JPH09160350A (en) * | 1995-12-08 | 1997-06-20 | Seiko Epson Corp | Contact electrification device |
-
1993
- 1993-07-30 JP JP05208810A patent/JP3080125B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0716354A2 (en) * | 1994-12-07 | 1996-06-12 | Canon Kabushiki Kaisha | Reconditioning method for charging roller |
| EP0716354A3 (en) * | 1994-12-07 | 1997-07-09 | Canon Kk | Reconditioning method for charging roller |
| JPH09160350A (en) * | 1995-12-08 | 1997-06-20 | Seiko Epson Corp | Contact electrification device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3080125B2 (en) | 2000-08-21 |
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