JPH01581A - Developer carrier in dry developing device - Google Patents
Developer carrier in dry developing deviceInfo
- Publication number
- JPH01581A JPH01581A JP63-39048A JP3904888A JPH01581A JP H01581 A JPH01581 A JP H01581A JP 3904888 A JP3904888 A JP 3904888A JP H01581 A JPH01581 A JP H01581A
- Authority
- JP
- Japan
- Prior art keywords
- developer
- developer carrier
- developing device
- conductive filler
- average particle
- 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
- 239000011347 resin Substances 0.000 claims description 23
- 229920005989 resin Polymers 0.000 claims description 23
- 239000002245 particle Substances 0.000 claims description 15
- 239000011231 conductive filler Substances 0.000 claims description 14
- 239000011247 coating layer Substances 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 6
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical group 0.000 claims description 2
- 239000004065 semiconductor Substances 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 15
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 10
- 229920000728 polyester Polymers 0.000 description 7
- 239000000945 filler Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000010186 staining Methods 0.000 description 4
- 230000007613 environmental effect Effects 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- 239000004593 Epoxy Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 206010047571 Visual impairment Diseases 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 108091008695 photoreceptors Proteins 0.000 description 1
- 210000004761 scalp Anatomy 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
（技術分野）
この発明は電子写真複写機や静電記録装置における一成
分現像剤を用いた乾式現像装置の現像剤担持体に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a developer carrier for a dry type developing device using a one-component developer in an electrophotographic copying machine or an electrostatic recording device.
（従来技術）
感光体ドラムなどの静電潜像担持体上の静電潜像に一成
分現像剤を接触させて静電潜像を現像する手段として用
いられている現像ローラなどの現像剤担持体の周面に電
気絶縁性の樹脂層を設けたものが知られている。このよ
うな現像剤担持体では、現像後の現像剤担持体上の現像
剤層における電気残像を除去するために、現像剤担持体
上の樹脂層を構成する樹脂として、電気伝導度が比較的
高いウレタン、エポキシ等の極性の強い材料を選定する
必要があった。これらの材料は、温湿度の環境の変化に
よってその電気伝導度が大きく変動し、安定した現像特
性を得ることが困難であるという問題点があった。(Prior art) A developer carrying device such as a developing roller is used as a means for developing an electrostatic latent image by bringing a one-component developer into contact with the electrostatic latent image on an electrostatic latent image carrier such as a photoreceptor drum. It is known that an electrically insulating resin layer is provided on the circumferential surface of the body. In such a developer carrier, in order to remove the electrical afterimage in the developer layer on the developer carrier after development, the resin constituting the resin layer on the developer carrier has a relatively low electrical conductivity. It was necessary to select highly polar materials such as high-quality urethane and epoxy. These materials have a problem in that their electrical conductivity fluctuates greatly depending on environmental changes in temperature and humidity, making it difficult to obtain stable development characteristics.
また現像剤担持体上の樹脂層を絶縁性の高いアクリル系
樹脂などで形成し、その樹脂層に現像剤粒径よりも大き
い電極を島状に点在させたものにおいては、低帯電現像
剤に対し現像阻止方向のバイアス電圧が大きい場合に上
記電極から現像剤への電荷の移動が起こり、逆極性帯電
現像剤が発生して現像剤の消費量が増大するという開運
点があった４
上述の環境変化による現像特性の変動は、樹脂の水分の
吸収、発散に起因する現像剤担持体上の樹脂層の電気抵
抗変動によることがわかった。In addition, in the case where the resin layer on the developer carrier is formed of a highly insulating acrylic resin, etc., and the resin layer is dotted with island-like electrodes larger than the developer particle size, it is possible to use a low-charge developer. On the other hand, when the bias voltage in the development blocking direction is large, charge transfer from the electrode to the developer occurs, and there is a turning point where oppositely charged developer is generated and the amount of developer consumed increases.4 As mentioned above. It was found that fluctuations in development characteristics due to environmental changes are due to fluctuations in the electrical resistance of the resin layer on the developer carrier due to the absorption and release of moisture by the resin.
（目 的）
この発明は、上述の問題点を解消した一成分現像剤を用
いる乾式現像装置における現像剤担持体を提供すること
にある。(Objective) The present invention provides a developer carrier in a dry type developing device using a one-component developer that solves the above-mentioned problems.
（構 成）
この発明は乾式現像装置を構成する現像剤担持体に、体
積固有抵抗“が１００Ωｃｍ以下の材料からなる導電性
フィラーを分散した樹脂コート層を設けたものである。(Structure) This invention provides a developer carrier constituting a dry developing device with a resin coating layer in which a conductive filler made of a material having a volume resistivity of 100 Ωcm or less is dispersed.
第１図において、符号１は電子写真法によって得られた
静電潜像を表面に有する潜像担持体たる感光体ドラムを
示す。上記静電潜像は、現像剤担持体としての現像ロー
ラ２によって一成分現像剤が供給されることによって現
像される。現像ローラ２には、現像剤を摩擦帯電する機
能をもったスポンジゴムローラ３によって現像剤槽内の
現像剤が供給される。一成分現像剤としては、摩擦帯電
し得る程度の高抵抗トナーが用いられる。In FIG. 1, reference numeral 1 denotes a photosensitive drum which is a latent image carrier having an electrostatic latent image obtained by electrophotography on its surface. The electrostatic latent image is developed by supplying a one-component developer by a developing roller 2 serving as a developer carrier. The developing roller 2 is supplied with developer in a developer tank by a sponge rubber roller 3 having a function of frictionally charging the developer. As the one-component developer, a high-resistance toner that can be triboelectrically charged is used.
現像ローラ２は芯金軸４．この芯金軸４の設けられたゴ
ム層５及びゴム層５に設けられた樹脂コート層６で構成
されており、芯金軸４の直径は８１、ゴム層５は厚さ６
ａ＋ｍ、アクリロニトリルゴム（ＮＢＲ−ｆム）であり
、樹脂コート層としては、体積平均粒径１μｍ以下のフ
ィラーをポリエステルウレタンに０．１０〜１．６の割
合で分散した層厚５〜１００μｍのフィラー分散樹脂が
用いられている。The developing roller 2 has a core metal shaft 4. It is composed of a rubber layer 5 on which the core metal shaft 4 is provided and a resin coating layer 6 provided on the rubber layer 5.The diameter of the core metal shaft 4 is 81, and the thickness of the rubber layer 5 is 6.
a+m, acrylonitrile rubber (NBR-f), and the resin coating layer is a filler with a layer thickness of 5 to 100 μm, in which filler with a volume average particle diameter of 1 μm or less is dispersed in polyester urethane at a ratio of 0.10 to 1.6. Dispersion resin is used.
感光体ドラム１上の静電潜像の現像は、現像ローラ２の
樹脂コート層６を接触させた状態で行わわる。ゴム層５
は、実質的に剛体である感光体ドラム１と現像ローラ２
との良好な接触状態を保たせるのに有効である。Development of the electrostatic latent image on the photosensitive drum 1 is performed with the resin coat layer 6 of the developing roller 2 in contact with the developing roller 2 . rubber layer 5
The photosensitive drum 1 and the developing roller 2 are substantially rigid bodies.
This is effective in maintaining good contact with the
実施例１
体積平均粒径１μｍ以下１体積固有抵抗が１００Ωｃｍ
以下のＴｉＯ・（チタンブラック、三菱金属株式会社製
２０Ｍ）からなるフィラーを、フィラー／ポリエステル
ウレタン比＝１．４で分散した層厚３０μ■の樹脂コー
トをＮＢＲゴムロールに設けた現像剤担持体。Example 1 Volume average particle diameter 1 μm or less 1 volume resistivity 100 Ωcm
A developer carrier comprising an NBR rubber roll coated with a resin coat having a thickness of 30 μι in which a filler made of TiO (Titanium Black, 20M manufactured by Mitsubishi Metals Corporation) as shown below is dispersed at a filler/polyester urethane ratio of 1.4.
２、実施例２
体積平均粒径１μｍ以下１体積固有抵抗が１００Ωａｍ
以下の５ｎＯｚ （Ｓｂ３０ｚ含有）からなるフィラー
を、フィラー／ポリエステルウレタン比＝０．６で分散
した層厚３０μ田の樹脂コートをＮＩＩＲゴムロールに
設けた現像剤担持体。2. Example 2 Volume average particle diameter 1 μm or less 1 volume resistivity 100 Ωam
A developer carrier in which a NIIR rubber roll is coated with a resin coat having a layer thickness of 30 μm in which a filler consisting of the following 5 nOz (containing Sb30z) is dispersed at a filler/polyester urethane ratio of 0.6.
この実施例において、５ｎＯ２（Ｓｂｓ ０２含有）は
、正の温度係数をもった抵抗体で、いわゆるＰＴＣと呼
ばれる金属酸化物半導体である。第２図は、５ｎＯｚ（
Ｓｂ＋ｓＯｚ含有）からなる導電性フィラーとポリエス
テルウレタンとの比Ｆ／Ｐを０．４から０．８に変化さ
せたときの大気中の水蒸気分圧Ｐａ （ｍｍｌ１ｇ）に
対するローラ表層の抵抗（Ω）の変化を示しており、こ
のグラフかられかるように、Ｆ／ＰがＯおよび０．８の
ときローラ表層抵抗が急激な変化を示し、従ってＦ／Ｐ
がＯおよび０．８以上では所期の目的が達成されず、０
．５〜０．７が好適な範囲である。In this example, 5nO2 (containing Sbs02) is a resistor having a positive temperature coefficient, and is a metal oxide semiconductor called PTC. Figure 2 shows 5nOz (
Resistance (Ω) of the roller surface layer against atmospheric water vapor partial pressure Pa (mml 1g) when the ratio F/P of the conductive filler (containing Sb + sOz) and polyester urethane is changed from 0.4 to 0.8. As can be seen from this graph, when F/P is O and 0.8, the roller surface resistance shows a rapid change, and therefore F/P
If it is 0 or more than 0.8, the intended purpose will not be achieved, and 0.
．． A suitable range is 5 to 0.7.
ところで５ｎＯｚ （Ｓｂ９０２含有）などのＰＴＣか
らなる導電性フィラーとポリエステルウレタンとの比、
すなわちＦ／Ｐが大きくなると、この導電性フィラーの
電気的性質が支配的となって、Ｆ／Ｐが比較的小さい場
合に、低温低湿環境下で高抵抗を示したものが、これと
は逆に低抵抗となる。By the way, the ratio of conductive filler made of PTC such as 5nOz (containing Sb902) and polyester urethane,
In other words, when F/P becomes large, the electrical properties of this conductive filler become dominant, and when F/P is relatively small, the material that showed high resistance in a low temperature and low humidity environment becomes opposite to this. has low resistance.
このような結果は、導電性フィラーとポリエステルウレ
タンの他、アクリルウレタンなどのウレタン系、フッ素
系、エポキシ系の樹脂Ｒとの比Ｆ／Ｒを０．５〜０．７
に選ぶことによっても得られ、環境依存性の小さい樹脂
コート層を実現することができる。このような効果は、
一般に知られている起伝導材料についても見られる。た
だしその最適なＦ／Ｒは、上記０．５〜０．７の値から
材質の組合せで多少前後する。These results indicate that the ratio F/R of the conductive filler and polyester urethane, urethane-based resin such as acrylic urethane, fluorine-based resin, and epoxy-based resin R is 0.5 to 0.7.
It is also possible to achieve a resin coating layer with low environmental dependence. Such an effect is
This can also be seen in commonly known conductive materials. However, the optimum F/R varies somewhat from the above value of 0.5 to 0.7 depending on the combination of materials.
実施例３
体積平均粒径１μｍ以下、体積固有抵抗が１００Ωｃｎ
ｌ以下のカーボンブラック（キャボット社製。Example 3 Volume average particle diameter 1 μm or less, volume resistivity 100 Ωcn
1 or less carbon black (manufactured by Cabot).
ブラックパールＬ、リーガル＄４００）からなるフィラ
ーを、フィラー／ポリエステルウレタン比＝０．１３で
分散した層厚３０μｌの樹脂コートをＮＢ［！ゴムロー
ルに設けた現像剤担持体。NB [! A developer carrier mounted on a rubber roll.
上記の各実施例における現像剤担持体を、 １０℃。The developer carrier in each of the above examples was heated to 10°C.
１５％円１の環境下に２４時間放置したときの該担持体
の表層抵抗は略ｌＸｌ０”Ωを示した。この現像剤担持
体によって、静電潜像担持体上の画像部電位が−２００
Ｖ、非画像部電位（地肌部）が−９００Ｖ、そして、現
像剤担持体へのバイアス印加電圧が−５００Ｖという条
件下で反転現像を行ったところ地肌汚れは生じなかった
。さらに現像剤担持体に対するバイアス電圧を一８５０
ｖにして、該担持体と地肌部との間の電位差、すなわち
現像電位差を５０Ｖに下げて現像を行っても地肌汚れは
生じなかった・
しかし、導電性フィラーとポリエステルウレタンとの比
が各実施例の値以下では現像剤担持体の表層抵抗が１０
１２Ωを越え、地肌汚れを生じた。そして上記の比が各
実施例の値以上の現像剤担持体では表層抵抗がｌＸｌ０
’ Ω以下になり、これまた地肌汚れが生じた。The surface resistance of the carrier when left for 24 hours in an environment of 15% yen 1 was approximately 1X10''Ω.With this developer carrier, the potential of the image area on the electrostatic latent image carrier was -200Ω.
When reversal development was performed under the following conditions: V, the non-image area potential (background area) was -900V, and the bias voltage applied to the developer carrier was -500V, no background staining occurred. Furthermore, the bias voltage to the developer carrier is set to -850.
Even when the development was carried out by lowering the potential difference between the carrier and the background part, that is, the development potential difference, to 50 V, no background staining occurred. Below the example value, the surface resistance of the developer carrier is 10
It exceeded 12Ω, causing staining of the background. In a developer carrier in which the above ratio is greater than the value of each example, the surface resistance is lXl0
' Ω or less, and the scalp became dirty again.
表層抵抗がＩ×１０１２Ωを越えた場合の地肌汚れは、
現像剤担持体へのバイアス電圧を調整することによっで
ある程度軽減できたが１表層抵抗がＩ×１０９ Ωを下
まわる場合の地肌汚れはバイアス電圧の：１１ｖｌで軽
減することは回置であった。これは表層抵抗の比較的低
い現像剤担持体から現像剤への電荷の移動が発生し、そ
のために現像剤の帯電極性が反転したものと考えられる
。If the surface resistance exceeds I x 1012 Ω, the skin stains are as follows:
Although it was possible to reduce the problem to some extent by adjusting the bias voltage to the developer carrier, the background staining when the surface resistance was less than I×109 Ω could be reduced by adjusting the bias voltage to 11vl. Ta. This is thought to be due to the transfer of charge from the developer carrier, which has a relatively low surface resistance, to the developer, which caused the charge polarity of the developer to be reversed.
現像剤担持体上に形成される一成分現像剤の薄層の表面
はできる限り滑かであることが望しい。It is desirable that the surface of the thin layer of one-component developer formed on the developer carrier be as smooth as possible.
従って、現像剤担持体の樹脂コート層の厚さは。Therefore, the thickness of the resin coating layer of the developer carrier is.
導電性フィラーの体積平均粒径よりも大きい方がよい。It is better that the particle size is larger than the volume average particle size of the conductive filler.
また導電性フィラーの体積平均粒径は現像剤粒子の体積
平均粒径以下、好ましくは１／４以下であることが望し
い。Further, it is desirable that the volume average particle size of the conductive filler is equal to or less than the volume average particle diameter of the developer particles, preferably 1/4 or less.
（効 果）
本発明によれば、温度、湿度の変化する環境下において
も、表層抵抗の変動幅が小さく、地汚れのない安定した
画質のコピーが得られる。(Effects) According to the present invention, even in an environment where temperature and humidity change, the range of variation in surface layer resistance is small, and copies with stable image quality without background smear can be obtained.
第１図は本発明による現像剤担持体を用いた乾式現像装
置の一例を示す側面図、第２図は導電性フィラーとポリ
エステルウレタンとの比を変化させたときの大気中の水
蒸気分圧に対するローラ表層の抵抗の変化を示すグラフ
である。
１・・・・静電潜像担持体、２・・・・現像剤担持体。
６・・・・樹脂コート層。FIG. 1 is a side view showing an example of a dry developing device using the developer carrier according to the present invention, and FIG. 2 is a diagram showing the partial pressure of water vapor in the atmosphere when the ratio of conductive filler to polyester urethane is varied. It is a graph showing the change in resistance of the roller surface layer. 1... Electrostatic latent image carrier, 2... Developer carrier. 6...Resin coat layer.
Claims (1)
する現像剤担持体に一成分現像剤を供給し、上記一成分
現像剤を静電潜像担持体に接触させることによって静電
潜像を現像する現像装置において、体積固有抵抗が１０
０Ωｃｍ以下の材料からなる導電性フィラーを分散した
樹脂コート層を周面に有する乾式現像装置における現像
剤担持体。 ２、導電性フィラーの体積平均粒径が現像剤の体積平均
粒径以下である請求項第１項記載の乾式現像装置におけ
る現像剤担持体。 ３、導電性フィラーの体積平均粒径が現像剤の体積平均
粒径の１／４以下である請求項第２項記載の乾式現像装
置における現像剤担持体。 ４、樹脂コート層を導電性フィラーの体積平均粒径以上
である請求項第１項又は第２項又は第３項記載の乾式現
像装置における現像剤担持体。 ５、導電性フィラーが正の温度係数をもった金属酸化物
半導体である請求項第１項又は第２項又は第３項又は第
４項記載の乾式現像装置における現像剤担持体。[Scope of Claims] 1. A one-component developer is supplied to a developer carrier having a resin coating layer on the circumference in which a conductive filler is dispersed, and the one-component developer is brought into contact with the electrostatic latent image carrier. In a developing device that develops an electrostatic latent image, the volume resistivity is 10
A developer carrier for a dry type developing device, which has a resin coating layer on its circumferential surface in which a conductive filler made of a material having a resistance of 0 Ωcm or less is dispersed. 2. The developer carrier in a dry developing device according to claim 1, wherein the volume average particle size of the conductive filler is equal to or less than the volume average particle size of the developer. 3. The developer carrier in a dry developing device according to claim 2, wherein the volume average particle size of the conductive filler is 1/4 or less of the volume average particle size of the developer. 4. The developer carrier in a dry developing device according to claim 1, 2 or 3, wherein the resin coating layer has a volume average particle diameter equal to or larger than that of the conductive filler. 5. The developer carrier in a dry developing device according to claim 1, 2, 3, or 4, wherein the conductive filler is a metal oxide semiconductor having a positive temperature coefficient.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63039048A JP2746370B2 (en) | 1987-02-23 | 1988-02-22 | Developer carrier in dry developing device |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62-39614 | 1987-02-23 | ||
| JP3961487 | 1987-02-23 | ||
| JP63039048A JP2746370B2 (en) | 1987-02-23 | 1988-02-22 | Developer carrier in dry developing device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JPS64581A JPS64581A (en) | 1989-01-05 |
| JPH01581A true JPH01581A (en) | 1989-01-05 |
| JP2746370B2 JP2746370B2 (en) | 1998-05-06 |
Family
ID=26378360
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63039048A Expired - Fee Related JP2746370B2 (en) | 1987-02-23 | 1988-02-22 | Developer carrier in dry developing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2746370B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4688933A (en) * | 1985-05-10 | 1987-08-25 | The Laitram Corporation | Electro-optical position determining system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54155050A (en) * | 1978-05-26 | 1979-12-06 | Ricoh Co Ltd | Device for developing electrostatic latent image |
| JPS60115964A (en) * | 1983-11-29 | 1985-06-22 | Ricoh Co Ltd | Manufacture of developer carrying body |
| JPS60254064A (en) * | 1984-05-30 | 1985-12-14 | Tokai Rubber Ind Ltd | Electrostatic charging control roller for toner supply |
| JPS61176959A (en) * | 1985-01-31 | 1986-08-08 | Ricoh Co Ltd | Developing device |
-
1988
- 1988-02-22 JP JP63039048A patent/JP2746370B2/en not_active Expired - Fee Related
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4908665A (en) | Developer carrier containing electrically conductive filler present in a resin coating layer for use in dry-type image developing device | |
| JPH0799442B2 (en) | Contact charging device | |
| JPH01581A (en) | Developer carrier in dry developing device | |
| JP2746370B2 (en) | Developer carrier in dry developing device | |
| JPH0836316A (en) | Contact transferring device | |
| JPS6219749B2 (en) | ||
| JP2927159B2 (en) | Electrophotographic charging roll | |
| JPH0410635B2 (en) | ||
| JP3279923B2 (en) | Electrophotographic equipment | |
| JP4574907B2 (en) | Conductive member, process cartridge, and electrophotographic apparatus | |
| JPS6356973B2 (en) | ||
| JP2746370C (en) | ||
| JP3277718B2 (en) | Electrophotographic charging roll | |
| JPS5887572A (en) | Roller transferring device | |
| JP3126636B2 (en) | Charging member, charging device, and image forming apparatus | |
| US5747207A (en) | Electrophotographic apparatus with charge injection layer on photosensitive member | |
| JP3330009B2 (en) | Electrophotographic equipment | |
| JPH1020633A (en) | Image forming device provided with developing bias control function | |
| JP2004086210A (en) | Long-life charging device | |
| JPH0415949B2 (en) | ||
| JP3714567B2 (en) | Electrophotographic equipment | |
| JPH09274358A (en) | Contact electrostatic charging member | |
| JPH09297464A (en) | Electrophotographic device | |
| JP2888949B2 (en) | Conductive roll | |
| JPH07261412A (en) | Electrostatic charge latent image bearing body |