JPH04212183A - Developing method and its device - Google Patents
Developing method and its deviceInfo
- Publication number
- JPH04212183A JPH04212183A JP3015778A JP1577891A JPH04212183A JP H04212183 A JPH04212183 A JP H04212183A JP 3015778 A JP3015778 A JP 3015778A JP 1577891 A JP1577891 A JP 1577891A JP H04212183 A JPH04212183 A JP H04212183A
- Authority
- JP
- Japan
- Prior art keywords
- electric field
- developer
- developing
- developing roller
- carrier
- 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
- 238000000034 method Methods 0.000 title claims abstract description 19
- 230000005684 electric field Effects 0.000 claims description 100
- 108091008695 photoreceptors Proteins 0.000 description 41
- 230000002123 temporal effect Effects 0.000 description 28
- 238000010586 diagram Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 230000001105 regulatory effect Effects 0.000 description 5
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 229920006311 Urethane elastomer Polymers 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000010186 staining Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 230000005685 electric field effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Dry Development In Electrophotography (AREA)
- Developing For Electrophotography (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、電子写真複写機、プリ
ンタあるいはファクシミリ等の画像形成装置に採用され
る現像方法及びその装置に係り、詳しくは現像剤を現像
剤担持体上に担持し、静電潜像担持体と対向する現像部
に搬送して現像を行なう現像方法及びその装置に関する
ものである。TECHNICAL FIELD The present invention relates to a developing method and device used in image forming apparatuses such as electrophotographic copying machines, printers, and facsimile machines, and more specifically, the present invention relates to a developing method and apparatus for use in image forming apparatuses such as electrophotographic copying machines, printers, and facsimile machines. The present invention relates to a developing method and apparatus in which a latent electrostatic image carrier is conveyed to a developing section opposite to it and developed.
【０００２】0002
【従来の技術】この種の現像方法としては、表面に現像
剤の薄層を形成した現像剤担持体と静電潜像担持体とを
、現像部において対向させ、この現像部に現像剤担持体
上の現像剤を静電潜像担持体へ転移させ得るような電界
を形成して、静電潜像担持体上の静電潜像を現像するも
のが知られている。そして、この現像方法においては、
現像剤担持体から静電潜像担持体に現像剤が転移するた
めの閾値があり、この閾値を超える表面電位を有する画
像部には、現像剤付着が生じるが、逆に閾値以下の表面
電位を有する画像部にはほとんど現像剤付着が生じない
ので、所謂γの立った階調性の悪い画像になるという不
具合がある。しかし、この不具合は、現像部に比較的低
周波の交互電界を形成することによって解決できること
が知られている（例えば、特公昭６４−１０１３号公報
参照）。[Prior Art] In this type of developing method, a developer carrier with a thin layer of developer formed on its surface and an electrostatic latent image carrier are placed opposite each other in a developing section, and the developing section carries the developer. It is known to develop an electrostatic latent image on an electrostatic latent image carrier by forming an electric field that can transfer the developer on the body to the electrostatic latent image carrier. In this developing method,
There is a threshold value for developer to transfer from the developer carrier to the electrostatic latent image carrier, and developer adhesion occurs in image areas with a surface potential exceeding this threshold value, but conversely, when the surface potential is below the threshold value, developer adhesion occurs. Since there is almost no developer adhesion in the image area having .gamma., there is a problem that the image has so-called γ and poor gradation. However, it is known that this problem can be solved by forming an alternating electric field of relatively low frequency in the developing section (see, for example, Japanese Patent Publication No. 1013/1983).
【０００３】ところが、単に現像部に低周波の交互電界
を印加するだけでは、交互電界の条件を階調性を向上さ
せ得るものにすると画像濃度が低下し、逆に交互電界の
条件を画像濃度を上げるものにすると画像の線部が太っ
てしまうという問題点があった。又、この種の現像方法
においては、特に現像剤として非磁性トナーを使用する
と、非磁性トナーの往復運動を生じさせた際、トナーが
パウダークラウド化して画像濃度の低下が著しいという
問題点もあった（例えば、特公昭２−１４７０６号公報
参照）。そして、近年、画像形成装置で作成される画像
の出力情報が多様化するに伴い、従来よりも更に高画質
化が望まれている。However, simply applying a low-frequency alternating electric field to the developing section results in a decrease in image density if the conditions of the alternating electric field are set to improve gradation; There was a problem in that when the line was raised, the lines in the image became thicker. In addition, in this type of development method, there is a problem that, especially when non-magnetic toner is used as a developer, when the non-magnetic toner is caused to reciprocate, the toner becomes a powder cloud, resulting in a significant decrease in image density. (For example, see Japanese Patent Publication No. Sho 2-14706). In recent years, as the output information of images created by image forming apparatuses has become more diverse, there has been a demand for higher image quality than ever before.
【０００４】0004
【発明が解決しようとする課題】本発明は従来技術の有
するこのような問題点に鑑みなされたものであり、その
目的とするところは、階調性を維持しつつ画像濃度を向
上させ且つ画像の線部の太りも防止することが出来、こ
れにより、高画質の画像を得ることを可能とする現像方
法及びその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-mentioned problems of the prior art, and its objects are to improve image density while maintaining gradation, and to improve image quality. It is an object of the present invention to provide a developing method and an apparatus thereof, which can prevent the line portions from becoming thick and thereby make it possible to obtain high-quality images.
【０００５】[0005]
【課題を解決するための手段】上記の目的を達成するた
めに、本発明は、現像剤担持体上に現像剤を担持し、該
現像剤担持体と静電潜像担持体が互いに対向する現像部
において現像を行なう現像装置において、該現像剤担持
体として表面に多数の電界配置を形成した現像剤担持体
と、該現像部に電界を形成するための電圧印加手段とを
有し、該静電潜像担持体上の電位と、該現像剤担持体上
の電位と、該電圧印加手段によって形成される電界との
相互関係で決定される電界により現像剤の移動を制御す
ることを特徴とするものである。[Means for Solving the Problems] In order to achieve the above object, the present invention carries a developer on a developer carrier, and the developer carrier and the electrostatic latent image carrier face each other. A developing device that performs development in a developing section includes a developer carrier having a plurality of electric field arrangements formed on its surface as the developer carrier, and voltage application means for forming an electric field in the developing section, The movement of the developer is controlled by an electric field determined by the interaction between the potential on the electrostatic latent image carrier, the potential on the developer carrier, and the electric field formed by the voltage application means. That is.
【０００６】[0006]
【作用】本発明は、現像剤を担持する現像剤担持体とし
て、表面に多数の電界配置を形成した現像剤担持体を用
い、且つ、この現像剤担持体と静電潜像担持体が互いに
対向する現像部に電圧印加手段で電界を形成して、該静
電潜像担持体上の電位と、該現像剤担持体上の電位と、
該電圧印加手段によって形成される電界との相互関係で
決定される電界により現像剤の移動を制御し、これによ
り、静電潜像担持体上の静電潜像に適量の現像剤を付着
させるように作用するものである。[Operation] The present invention uses a developer carrier having a large number of electric field arrangements formed on its surface as a developer carrier, and furthermore, the developer carrier and the electrostatic latent image carrier are connected to each other. An electric field is formed in the opposing developing sections by a voltage applying means to increase the potential on the electrostatic latent image carrier and the potential on the developer carrier,
The movement of the developer is controlled by an electric field determined by the interaction with the electric field formed by the voltage applying means, thereby causing an appropriate amount of developer to adhere to the electrostatic latent image on the electrostatic latent image carrier. It works like this.
【０００７】[0007]
【実施例】以下、本発明の実施例を図面に基づいて詳細
に説明する。図１は、本発明による現像方法を実施する
ために適した本発明による現像装置の一実施例の全体構
成を示す図である。現像装置２のケーシングには感光体
ドラム３に対向する部分に現像用の開口が設けられてお
り、現像ローラ１はこの開口を介して感光体ドラム３に
所定の間隙を保持してケーシング内に回転可能に設けら
れている。現像ローラ１の周囲には、該ローラ１に担持
搬送されるトナー層の層厚を規制するブレード部材４が
ローラ１の上方に弾発的に圧接するように設けられてお
り、これによりケーシング内に形成されたトナータンク
５からアジテータ６及びトナー供給ローラ８の回転にと
もない供給されたトナー７を層厚規制するようにされて
いる。このブレード部材４に代え、規制ローラや規制ベ
ルトを用いても良い。アジテータ６は矢印で示す時計方
向に回転し、その先端部分の抵抗でトナー７を撹拌する
と共に図において左方に移動させる。上記のトナー供給
ローラ８は、ウレタンゴムを発泡させて作られたスポン
ジ材料や、ポリエステル、４弗化エチレン樹脂等を繊維
にしてブラシ状にしたものにより構成される。このトナ
ー供給ローラ８はアジテータ６により搬送されてきたト
ナー７を現像ローラ１の表面に順方向あるいは逆方向に
こすり付けて供給すると共に、現像に使用されずに現像
ローラ１上に残って戻ってきたトナー７を掻き落す作用
をするものである。トナー供給ローラ８により現像ロー
ラ１の表面に供給されたトナー７は、トナー供給ローラ
８又は現像ローラ１との相互摩擦により発生する摩擦帯
電作用によりトナー７自体も帯電して現像ローラ１の表
面に静電的に担持される。かくして現像ローラ１に担持
搬送されるトナー７は、現像ローラ１の上方に弾発的に
圧接するブレード部材４により層厚規制され、感光体ド
ラム３と現像ローラ１とが対向する現像部に搬送される
。ブレード部材４は、弾性を有する板ばねにウレタンゴ
ム等のトナー帯電性能を有する材料を貼り合わせて製作
しても、あるいは弾性を有する部材をそのまま用いても
良い。ブレード部材４は、現像ローラ１の回転方向に対
して図に示すごとくトレーリング方向に設けても良いし
、逆方向のリーディング方向に設けても良い。現像ロー
ラ１及びトナー供給ローラ８には、現像バイアス印加手
段９が接続されている。又、ブレード部材４にバイアス
印加手段９を接続しても良い。感光体ドラム３上に形成
された静電潜像の現像は、現像ローラ１にバイアス電圧
印加の下に静電潜像に応じて所要量のトナー７を現像ロ
ーラ１から静電潜像に転移させることにより行なわれる
。現像ローラ１は感光体ドラム３と実質的に接触しない
位置関係として３０〜５００μｍ、好ましくは５０〜２
５０μｍの間隙を保持して配置されている。その結果、
現像ローラ１を感光体ドラム３に接触させて静電潜像を
現像するときのような過大な負荷を必要としなくなり、
駆動モータを小型のものにすることが可能となる。
感光体ドラム３の周速度と、現像ローラ１の周速度とを
ほぼ等しくすれば、さらに駆動トルクの減少を図ること
が出来る。現像バイアス印加手段９による現像バイアス
としては、直流電界に加えて交流電界を組み合わせて用
いることが出来る。交流電界としては、矩形波のパルス
電界を、低周波である周波数３００〜２０００Ｈｚ、好
ましくは５００〜１５００Ｈｚの範囲に設定すると共に
、その高電圧部の時間と低電圧部の時間との１サイクル
の時間に対する比率を異なる比率とした波形にして用い
ると、低電圧部分のシャープ性も良く、高電圧部分の画
像濃度が高く、しかも地肌汚れの少ない優れた現像画像
を得ることが出来る。上記の高電圧部の時間と低電圧部
の時間との比率（デューティー比という）としては、静
電潜像の極性とトナー７の極性によってその最適比率が
異なるが、例えば負の静電潜像を負極性トナー７で反転
現像する場合、高電圧部（−１００Ｖ以上）の時間と低
電圧部（−８００Ｖ以下）の時間との比率を５〜１８：
２〜８とすれば良い。正規現像の際は、概ねこの比率を
逆転して用いれば同様の低電位部分のシャープ性も良く
、高電位部分の画像濃度が高く、しかも地肌汚れの少な
い優れた現像画像を得ることが出来る。Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the overall configuration of an embodiment of a developing apparatus according to the present invention suitable for carrying out the developing method according to the present invention. A developing opening is provided in the casing of the developing device 2 at a portion facing the photosensitive drum 3, and the developing roller 1 is inserted into the casing while maintaining a predetermined gap to the photosensitive drum 3 through this opening. It is rotatably provided. A blade member 4 that regulates the thickness of the toner layer carried and conveyed by the developing roller 1 is provided around the developing roller 1 so as to elastically press against the upper part of the roller 1. The layer thickness of the toner 7 supplied from the toner tank 5 formed in the toner tank 5 as the agitator 6 and toner supply roller 8 rotate is regulated. Instead of this blade member 4, a regulating roller or a regulating belt may be used. The agitator 6 rotates in the clockwise direction indicated by the arrow, and the resistance at its tip agitates the toner 7 and moves it to the left in the figure. The above-mentioned toner supply roller 8 is made of a sponge material made by foaming urethane rubber, polyester, tetrafluoroethylene resin, or the like into a fiber made into a brush shape. This toner supply roller 8 supplies the toner 7 conveyed by the agitator 6 by rubbing it on the surface of the developing roller 1 in the forward or reverse direction, and also returns the toner 7 remaining on the developing roller 1 without being used for development. This serves to scrape off the toner 7 that has been removed. The toner 7 supplied to the surface of the developing roller 1 by the toner supply roller 8 is also charged by the frictional charging effect generated by mutual friction with the toner supply roller 8 or the developing roller 1, and is applied to the surface of the developing roller 1. Electrostatically supported. In this way, the toner 7 carried and conveyed by the developing roller 1 is regulated in layer thickness by the blade member 4 that is elastically pressed against the upper side of the developing roller 1, and is conveyed to the developing section where the photosensitive drum 3 and the developing roller 1 face each other. be done. The blade member 4 may be manufactured by bonding a material having toner charging performance such as urethane rubber to an elastic leaf spring, or may be made by using an elastic member as is. The blade member 4 may be provided in a trailing direction as shown in the figure with respect to the rotational direction of the developing roller 1, or may be provided in a leading direction in the opposite direction. A developing bias applying means 9 is connected to the developing roller 1 and the toner supply roller 8 . Further, a bias applying means 9 may be connected to the blade member 4. The electrostatic latent image formed on the photoreceptor drum 3 is developed by applying a bias voltage to the developing roller 1 and transferring a required amount of toner 7 from the developing roller 1 to the electrostatic latent image according to the electrostatic latent image. It is done by letting The developing roller 1 has a positional relationship of 30 to 500 μm, preferably 50 to 2 μm, so as not to substantially contact the photoreceptor drum 3.
They are arranged with a gap of 50 μm maintained. the result,
This eliminates the need for an excessive load such as when developing an electrostatic latent image by bringing the developing roller 1 into contact with the photoreceptor drum 3.
It becomes possible to make the drive motor small. If the circumferential speed of the photosensitive drum 3 and the circumferential speed of the developing roller 1 are made approximately equal, the driving torque can be further reduced. As the developing bias by the developing bias applying means 9, an alternating current electric field can be used in combination in addition to a direct current electric field. As for the alternating current electric field, a rectangular wave pulse electric field is set at a low frequency of 300 to 2000 Hz, preferably 500 to 1500 Hz, and one cycle of the time of the high voltage part and the time of the low voltage part is set. By using waveforms with different ratios to time, it is possible to obtain an excellent developed image with good sharpness in the low voltage part, high image density in the high voltage part, and less background staining. The optimum ratio of the time in the high voltage section and the time in the low voltage section (called a duty ratio) differs depending on the polarity of the electrostatic latent image and the polarity of the toner 7. For example, when a negative electrostatic latent image When performing reversal development with negative polarity toner 7, the ratio of the time in the high voltage part (-100V or more) to the time in the low voltage part (-800V or less) is 5 to 18:
It may be set to 2 to 8. During regular development, by reversing this ratio, it is possible to obtain an excellent developed image with similarly good sharpness in low potential areas, high image density in high potential areas, and less background staining.
【０００８】ところで、本実施例では、現像ローラ１の
表面を微細に分割された導電性領域面と絶縁性領域面と
により構成している。図２（ａ）に、このような現像ロ
ーラ１の１例の外観を示す。図２（ｂ）はその表面部の
拡大断面図である。現像ローラ１は、抵抗又は誘電率の
異なる複数の材料で構成されている。図２（ａ）、（ｂ
）に示す例では導電性材料、例えばアルミニウム等の金
属素材あるいは導電性ゴムや導電性プラスチック２１の
ローラの表面に網目状にローレット加工を施し、その条
痕にポリカーボネート、アクリル、ポリエステル、４弗
化エチレン等の誘電体樹脂を摺り込んで充てんし、微細
な網目状の絶縁性領域面２２を形成すると共に、これに
接して微細な導電性領域面２１を形成している。微細な
導電性領域面２１と絶縁性領域面２２を形成する方法は
上記の例に限られるものではなく、各種の方法が採用可
能である。絶縁性領域の大きさは平均直径として３０〜
２０００μｍ、好ましくは５０〜１０００μｍである。
絶縁性領域面２２の形状が例えば円形であるときは、そ
の径Ｄ１（図３参照）を３０乃至２０００μｍ、好まし
くは１００乃至４００μｍ程度に設定し、その中心間距
離Ｐ１を、適宜バランス良く設定する。又絶縁性領域面
２２の形状が矩形であるときは、その一番短い辺の長さ
を３０乃至２０００μｍ程度とする。同様に、絶縁性領
域面２２の形状が長円形乃至は楕円形であるときは、そ
の短軸側の幅を３０乃至２０００μｍ程度とする。絶縁
性領域面２２の形状が他の形状のときも、これらに準じ
て、その幅を３０乃至２０００μｍ程度とする。又、そ
の占有面積比率としては、現像ローラ１表面積の５０〜
８０％、好ましくは６５〜７５％とすれば良い。現像ロ
ーラ１の構造をこのようにすることによって、トナー供
給ローラ８でトナー７を現像ローラ１にこすりつける時
に生ずる摩擦帯電作用によりトナー７を帯電して現像ロ
ーラ１の表面に充分な量のトナー７を担持することが出
来る。By the way, in this embodiment, the surface of the developing roller 1 is constituted by a conductive area surface and an insulating area surface which are finely divided. FIG. 2(a) shows the appearance of an example of such a developing roller 1. FIG. 2(b) is an enlarged sectional view of the surface portion. The developing roller 1 is made of a plurality of materials having different resistances or dielectric constants. Figure 2(a),(b)
), the surface of the roller is made of a conductive material, such as a metal material such as aluminum, conductive rubber, or conductive plastic 21, and the surface of the roller is knurled in a mesh pattern, and the grooves are coated with polycarbonate, acrylic, polyester, tetrafluoride, etc. A dielectric resin such as ethylene is rubbed and filled to form a fine mesh-like insulating region surface 22 and a fine conductive region surface 21 in contact therewith. The method of forming the fine conductive region surface 21 and the insulating region surface 22 is not limited to the above example, and various methods can be employed. The size of the insulating area is 30~ as an average diameter
It is 2000 μm, preferably 50 to 1000 μm. When the shape of the insulating region surface 22 is, for example, circular, its diameter D1 (see FIG. 3) is set to 30 to 2000 μm, preferably about 100 to 400 μm, and the center-to-center distance P1 is set appropriately and in a well-balanced manner. . When the shape of the insulating region surface 22 is rectangular, the length of the shortest side is about 30 to 2000 μm. Similarly, when the shape of the insulating region surface 22 is oval or elliptical, the width on the minor axis side is set to about 30 to 2000 μm. Even when the shape of the insulating region surface 22 is other shapes, the width is set to about 30 to 2000 μm according to these. In addition, its occupied area ratio is 50 to 50% of the surface area of the developing roller 1.
It may be set to 80%, preferably 65 to 75%. By configuring the developing roller 1 in this way, the toner 7 is charged by the frictional charging effect that occurs when the toner supply roller 8 rubs the toner 7 against the developing roller 1, and a sufficient amount of toner is deposited on the surface of the developing roller 1. 7 can be carried.
【０００９】この点について更に詳述する。現像ローラ
１の絶縁性領域面２２は、トナー供給ローラ６との摩擦
によってトナー７の帯電極性と反対の正極性に帯電され
る。一方、トナー供給ローラ８の周面に接触しながら現
像ローラ１に運ばれるトナー７は、トナー供給ローラ８
との摩擦によって負極性に摩擦帯電され、現像ローラ１
に供給されるが、このときこの現像ローラ１、特にその
絶縁性領域面２２との摩擦により更に負極性に強く摩擦
帯電され、現像ローラ１の周面に静電的に付着する。こ
のとき、現像ローラ１の各絶縁性領域面２２は正極性に
摩擦帯電していて、各絶縁性領域面２２に接して導電性
領域面２１が存在するので、現像ローラ１の表面は、多
数の絶縁性領域面２２のところだけに選択的に正極性の
電荷が付与された状態となっている。これにより図３に
示すように、正に帯電した各絶縁性領域面２２とそれに
接した導電性領域面２１との間に閉電界が形成され、現
像ローラ１の表面の近傍には無数の微小閉電界（マイク
ロフィールド）が形成される。即ち、電界の状態を表す
電気力線を考えた場合、現像ローラ１の表面近傍の空間
には、図３に円弧状の多数の線で表したように現像ロー
ラ１から出て同一の現像ローラ１に戻る電気力線が形成
され、各絶縁性領域面２２と導電性領域面２１との間に
閉電界が形成されるのである。各絶縁性領域面２２の面
積は前述のように微小であるため、各閉電界はフリンジ
ング効果（周辺電場効果）によってその強度が大変強く
なる。かかる閉電界によって、負に帯電したトナー７は
絶縁性領域面２２に強く引かれ、該ローラ１上に多量に
離れがたい状態で保持される。しかも、現像ローラ１に
保持されたトナー７がブレード部材４によって層厚を規
制されるとき、帯電の充分なトナー７は微小閉電界によ
って現像ローラ１の表面に強く保持されるが、帯電量の
小さなトナー７はブレード部材４との接触圧によって除
去され、結局、帯電量の大なるトナー７、例えば、５乃
至２０（好ましくは１０乃至１５）μＣ／ｇ程度に帯電
されたトナー７だけが現像間隙９へ運ばれる。[0009] This point will be explained in more detail. The insulating area surface 22 of the developing roller 1 is charged to a positive polarity opposite to the charging polarity of the toner 7 due to friction with the toner supply roller 6 . On the other hand, the toner 7 that is conveyed to the developing roller 1 while contacting the circumferential surface of the toner supply roller 8 is transferred to the toner supply roller 8.
The developing roller 1 is frictionally charged to a negative polarity by friction with the developing roller 1.
However, at this time, due to friction with the developing roller 1, especially its insulating region surface 22, it is triboelectrically charged to a stronger negative polarity and electrostatically adheres to the circumferential surface of the developing roller 1. At this time, each insulating area surface 22 of the developing roller 1 is frictionally charged to a positive polarity, and since the conductive area surface 21 exists in contact with each insulating area surface 22, the surface of the developing roller 1 is A positive charge is selectively applied only to the insulating region surface 22 of FIG. As a result, as shown in FIG. A closed electric field (microfield) is formed. That is, when considering electric lines of force that represent the state of the electric field, in the space near the surface of the developing roller 1, as shown by the many arc-shaped lines in FIG. 1 is formed, and a closed electric field is formed between each insulating region surface 22 and conductive region surface 21. Since the area of each insulating region surface 22 is minute as described above, the strength of each closed electric field becomes very strong due to the fringing effect (marginal electric field effect). Due to this closed electric field, the negatively charged toner 7 is strongly attracted to the insulating region surface 22 and is held on the roller 1 in large quantities in a state where it is difficult to separate. Moreover, when the layer thickness of the toner 7 held on the developing roller 1 is regulated by the blade member 4, the sufficiently charged toner 7 is strongly held on the surface of the developing roller 1 by a minute closed electric field, but the amount of charge is The small toner 7 is removed by the contact pressure with the blade member 4, and in the end, only the toner 7 with a large amount of charge, for example, the toner 7 charged to about 5 to 20 (preferably 10 to 15) μC/g, is developed. It is carried to gap 9.
【００１０】尚、本現像装置２においては、現像ローラ
１の表面に導電性領域面２１と絶縁性領域面２２とを混
在させたことにより、現像ローラ１とトナー供給ローラ
８のチャージアップは防止される。その理由としては、
絶縁性領域面２２ではトナーを帯電し、導電性領域面２
１ではトナー供給ローラの除電を行ない、全体としてバ
ランスのとれた帯電状態を維持する為と考えられる。こ
こでは現像バイアスとして印加する矩形波パルス電界が
現像ローラ１表面に存在する導電性領域面２１と絶縁性
領域面２２との間の微小電界と、帯電したトナーとに作
用し静電潜像の現像に好適な力学的エネルギーを与える
ものと考えられる。In the present developing device 2, the conductive area surface 21 and the insulating area surface 22 are mixed on the surface of the developing roller 1, thereby preventing the developing roller 1 and the toner supply roller 8 from being charged up. be done. The reason is that
The toner is charged on the insulating region surface 22, and the toner is charged on the conductive region surface 2.
In No. 1, the charge is removed from the toner supply roller to maintain a balanced charge state as a whole. Here, a rectangular wave pulsed electric field applied as a developing bias acts on the minute electric field between the conductive area surface 21 and the insulating area surface 22 on the surface of the developing roller 1 and on the charged toner, thereby forming an electrostatic latent image. It is thought that this provides suitable mechanical energy for development.
【００１１】以下、本発明のより具体的な実施例につい
て説明する。図４の（ａ）、（ｂ）、（ｃ）は夫々、現
像ローラ１の表面がローレット加工により導電性領域面
２１と絶縁性領域面２２が形成された例を示すものであ
る。これらの例ではローレットのピッチＰを０．３ｍｍ
とし、絶縁性領域面２２の巾Ｗを夫々、Ｗ１＝０．０７
５ｍｍ、Ｗ２＝０．１５ｍｍ、Ｗ３＝０．２２５ｍｍと
し、現像ローラ１表面に絶縁性領域面２２と導電性領域
面２１とが混在するように構成している。そして、これ
らの現像ローラ１を後述する実施例に用いた。More specific embodiments of the present invention will be described below. 4A, 4B, and 4C show examples in which the surface of the developing roller 1 is knurled to form a conductive region surface 21 and an insulating region surface 22, respectively. In these examples, the knurling pitch P is 0.3 mm.
and the width W of the insulating region surface 22 is W1=0.07.
5 mm, W2=0.15 mm, and W3=0.225 mm, and the surface of the developing roller 1 is configured to have an insulating region surface 22 and a conductive region surface 21 mixedly. These developing rollers 1 were used in Examples described later.
【００１２】先ず、第１実施例について説明する。
この実施例は、感光体ドラム３としてＯＰＣを用い、地
肌部の表面電位を−９００Ｖ、露光部の電位を−１００
Ｖとして、図４（ｂ）に示す表面形状を備えた現像ロー
ラ１を感光体ドラム３の表面と１００μｍの間隙をおい
て対向配置して反転現像を行なったものである。この現
像ローラ１表面の絶縁性領域面２２は、トナー供給ロー
ラ８でこすられて接地を基準とした電位が＋２００Ｖに
なる量の電荷を保持し、これにより、負極性に帯電した
トナー７を約１．０〜１．２ｍｇ／ｃｍ２担持した。そ
して、この現像ローラ１に現像バイアス印加手段９でピ
ーク・ツウ・ピーク（以下、Ｐ−Ｐという）１０００Ｖ
、最高電位０Ｖ、周波数５００Ｈｚ、デューティー比３
０％（Ｔ２／Ｔ１）のパルス電圧を印加した。First, a first embodiment will be explained. In this embodiment, an OPC is used as the photoreceptor drum 3, the surface potential of the background part is -900V, and the potential of the exposed part is -100V.
As V, a developing roller 1 having the surface shape shown in FIG. 4(b) is placed opposite to the surface of the photoreceptor drum 3 with a gap of 100 μm to perform reversal development. The insulating area surface 22 on the surface of the developing roller 1 holds an amount of charge such that the electrical potential becomes +200V with respect to the ground when rubbed by the toner supply roller 8, and thereby the negatively charged toner 7 is 1.0 to 1.2 mg/cm2 was supported. Then, the developing roller 1 is applied with a developing bias applying means 9 at a peak-to-peak (hereinafter referred to as P-P) voltage of 1000 V.
, maximum potential 0V, frequency 500Hz, duty ratio 3
A pulse voltage of 0% (T2/T1) was applied.
【００１３】図５は接地を基準とした現像ローラ１の表
面電位の時間的変化を示したものであり、（ａ）は絶縁
性領域面２２の表面電位について、（ｂ）は導電性領域
面２１の表面電位について示している。これらの図中に
は、感光体ドラム３表面の地肌部の表面電位のレベル（
−９００Ｖ）及び露光部の表面電位のレベル（−１００
Ｖ）を水平線として夫々示している。図５（ａ）中の絶
縁性領域面２２の表面電位の時間的変化を示す矩形連続
線から判るように、絶縁性領域面２２の表面電位は、現
像バイアス印加手段９による印加電圧が保持した電荷で
＋２００Ｖだけ偏倚された電位になる。一方、導電性領
域面２１の表面電位は、図５（ｂ）中のこの領域面２１
の表面電位の時間的変化を示す矩形連続線から判るよう
に、現像バイアス印加手段９による印加電圧そのものに
なる。FIG. 5 shows temporal changes in the surface potential of the developing roller 1 with reference to grounding, where (a) shows the surface potential of the insulating region surface 22, and (b) shows the surface potential of the conductive region surface. The surface potential of No. 21 is shown. In these figures, the level of surface potential (
-900V) and the surface potential level of the exposed area (-100V)
V) are shown as horizontal lines. As can be seen from the rectangular continuous line showing temporal changes in the surface potential of the insulating region surface 22 in FIG. 5(a), the surface potential of the insulating region surface 22 was maintained by the voltage applied by the developing bias applying means 9. The potential is biased by +200V due to the charge. On the other hand, the surface potential of the conductive region surface 21 is
As can be seen from the continuous rectangular line showing the temporal change in surface potential of , the voltage applied by the developing bias applying means 9 is itself.
【００１４】次に以上のように現像ローラ１表面の電位
が変化する場合の現像ローラ１表面と感光体ドラム３と
の間の電界について説明する。この電界は現像ローラ１
表面の絶縁性領域面２２上と導電性領域面２１上との何
れであるかによって、更に、夫々の領域面２２，２２に
ついて感光体ドラム３の画像部と地肌部との何れに対向
しているかによって異なる。Next, the electric field between the surface of the developing roller 1 and the photosensitive drum 3 when the potential on the surface of the developing roller 1 changes as described above will be explained. This electric field is the developing roller 1
Depending on whether it is on the insulating region surface 22 or the conductive region surface 21 of the surface, the region surface 22, 22 may be opposed to either the image area or the background area of the photoreceptor drum 3. It depends on the species.
【００１５】図６は、これらのうち図５（ｂ）に示すよ
うな表面電位の時間的変化を生じる導電性領域面２１上
の電界を説明するためのものであり、図６（ａ）はこの
領域面２１が感光体ドラム３の画像部（露光部）に対向
している場合の両者の電位差の時間的変化を示し、図６
（ｂ）はこの領域面２１が感光体ドラム３の非画像部（
未露光部）に対向している場合の両者の電位差の時間的
変化を示す。又、図７は図５（ａ）に示すような表面電
位の時間的変化を生じる絶縁性領域面２２上の電界を説
明するためのものであり、図７（ａ）はこの領域面２２
が感光体ドラム３の画像部（露光部）に対向している場
合の両者の電位差の時間的変化を示し、図７（ｂ）はこ
の領域面２２が感光体ドラム３の非画像部（未露光部）
に対向している場合の両者の電位差の時間的変化を示す
。FIG. 6 is for explaining the electric field on the conductive region surface 21 that causes the temporal change in surface potential as shown in FIG. 5(b), and FIG. 6(a) FIG. 6 shows a temporal change in the potential difference between the area surface 21 and the image area (exposed area) of the photoreceptor drum 3.
(b) shows that this area surface 21 is the non-image area of the photoreceptor drum 3 (
It shows the temporal change in the potential difference between the two when facing the unexposed area). Further, FIG. 7 is for explaining the electric field on the insulating region surface 22 that causes a temporal change in surface potential as shown in FIG. 5(a).
7(b) shows a temporal change in the potential difference between the two faces when the surface 22 faces the image area (exposed area) of the photoreceptor drum 3, and FIG. exposure area)
It shows the temporal change in the potential difference between the two when they are facing each other.
【００１６】これらの図においては、電界が現像ローラ
１表面に担持されたトナー７あるいは感光体ドラム３の
表面に担持されたトナー７に静電気力を及ぼすものであ
ることから、この静電気力の方向を区別するためにトナ
ー７が感光体ドラム３に向かう方向の電界に対応する上
記電位差を正、現像ローラ１に向かう方向の電界に対応
する上記電位差を負として表わしている。又、実験によ
って確認された、現像ローラ１上のトナー７が感光体ド
ラム３へ転移する上記電位差の閾値＋１００Ｖのレベル
と、感光体ドラム３上のトナー７が現像ローラ１の方へ
転移する電界の閾値−１００Ｖのレベルとを夫々水平線
で示し、且つ、この閾値を越えてトナー７の転移に寄与
する電界に対応する部分を斜線で表している。In these figures, since the electric field exerts an electrostatic force on the toner 7 carried on the surface of the developing roller 1 or the toner 7 carried on the surface of the photoreceptor drum 3, the direction of this electrostatic force is In order to distinguish between them, the potential difference corresponding to the electric field in the direction in which the toner 7 is directed toward the photosensitive drum 3 is expressed as positive, and the potential difference corresponding to the electric field in the direction in which the toner 7 is directed toward the developing roller 1 is expressed as negative. In addition, the level of the above-mentioned potential difference threshold value +100V at which the toner 7 on the developing roller 1 is transferred to the photoreceptor drum 3 and the electric field at which the toner 7 on the photoreceptor drum 3 is transferred toward the developing roller 1 were confirmed through experiments. The threshold value -100V level is shown by horizontal lines, and the portion corresponding to the electric field that exceeds this threshold value and contributes to the transfer of toner 7 is shown by diagonal lines.
【００１７】尚、上記の実験は現像ローラ１と感光体ド
ラム３との間隙を１００μｍとして、現像ローラ１に直
流電圧を印加し、この直流電圧の値を変化させながらト
ナーの転移を観察したものである。この例では現像電界
の閾値は１Ｖ／μｍであることが判った。又、この時用
いたトナー７の帯電電荷量を調べたところ約１０μＣ／
ｇであった。In the above experiment, the gap between the developing roller 1 and the photosensitive drum 3 was 100 μm, a DC voltage was applied to the developing roller 1, and the toner transfer was observed while changing the value of this DC voltage. It is. In this example, the threshold value of the developing electric field was found to be 1 V/μm. Also, when I checked the amount of charge of the toner 7 used at this time, it was about 10 μC/
It was g.
【００１８】現像ローラ１の導電性領域面２１上に存在
するトナー７は、感光体ドラム３の画像部と対向する場
合には、図６（ａ）の斜線部で示されるように＋９００
Ｖの電位差に対応する現像電界（以下、現像電界という
）になったときに感光体ドラム３の方向に転移するもの
と考えられ、感光体ドラム３の地肌部と対向する場合に
は、図６（ｂ）の斜線部で示されるように−９００Ｖの
現像電界になったときに現像ローラ１の方向に転移して
いるものと考えられる。When the toner 7 existing on the conductive area surface 21 of the developing roller 1 faces the image area of the photoreceptor drum 3, the toner 7 has a temperature of +900 as shown by the hatched area in FIG.
It is thought that the developing electric field (hereinafter referred to as developing electric field) corresponding to the potential difference of V is transferred in the direction of the photoreceptor drum 3, and when facing the background part of the photoreceptor drum 3, as shown in FIG. As shown by the hatched area in (b), it is considered that the particles are transferred in the direction of the developing roller 1 when the developing electric field reaches -900V.
【００１９】同様に、現像ローラ１の絶縁性領域面２２
上に存在するトナー７は、この絶縁性領域面２２が元々
＋２００Ｖに帯電しているので、感光体ドラム３の画像
部と対向する場合には、図７（ａ）の斜線部で示される
ように−３００Ｖの負電界と＋７００Ｖの正電界が交互
に現われ、正電界のときは現像ローラ１から感光体ドラ
ム３へ、負電界のときは感光体ドラム３から現像ローラ
１へ転移しているものと考えられる。又、感光体ドラム
３の地肌部と対向する場合には、図７（ｂ）の斜線部で
示すように、−１１００Ｖの負の電界で感光体ドラム３
から現像ローラ１へ転移し、交互に転移することはない
と考えられる。Similarly, the insulating area surface 22 of the developing roller 1
Since this insulating area surface 22 is originally charged to +200V, when the toner 7 existing on the upper surface faces the image area of the photoreceptor drum 3, the toner 7 is charged as shown by the hatched area in FIG. 7(a). A negative electric field of -300V and a positive electric field of +700V appear alternately, and when the electric field is positive, the electric field is transferred from the developing roller 1 to the photosensitive drum 3, and when the electric field is negative, the electric field is transferred from the photosensitive drum 3 to the developing roller 1. it is conceivable that. In addition, when facing the background part of the photoreceptor drum 3, as shown by the hatched area in FIG. 7(b), the photoreceptor drum 3 is
It is considered that the particles are transferred from the to the developing roller 1, and that they are not transferred alternately.
【００２０】以上のように現像ローラ１に担持されたト
ナー７は現像ローラ１表面に形成された電界で選択的に
その転移が制御されるのである。As described above, the transfer of the toner 7 carried on the developing roller 1 is selectively controlled by the electric field formed on the surface of the developing roller 1.
【００２１】このようにして得られた画像を、表面が全
てアルミニウムである現像ローラ１を用い、この結果図
６（ａ）及び（ｂ）に示すような現像電界のみで現像し
た画像と比較したところ、地肌汚れがなく濃度の高い画
像が得られ、しかも線図の再現性も優れていた。又、こ
の表面が全てアルミニウムである現像ローラを用い、本
実施例と同程度の線図の再現性を得ようとしたが画像濃
度が低下してしまった。The image thus obtained was compared with an image developed using only a developing electric field as shown in FIGS. 6(a) and 6(b) using a developing roller 1 whose surface was entirely made of aluminum. However, images with high density and no background stains were obtained, and the reproducibility of line drawings was also excellent. Further, an attempt was made to obtain the same level of line drawing reproducibility as in this embodiment by using a developing roller whose surface was entirely made of aluminum, but the image density was reduced.
【００２２】本実施例によれば、現像ローラ１の表面に
局部的に異なる現像バイアスが作用する領域を設けてお
り、この為、静電潜像を有する感光体ドラム３と表面に
トナーを担持した現像ローラ１との間にバイアスを印加
して現像を行なうときに、表面に選択的に電荷を保持せ
しめた現像ローラ１によって選択的にトナーの転移が制
御できるので、上記の効果を得ることが出来るものと考
えられる。即ち、絶縁性領域面２２上に存在するトナー
７には、その電界が図７（ａ）に示されるように、閾値
を超える正負の電界が作用しており、過剰なトナー付着
が抑制される一方、導電性領域面２１上に存在するトナ
ーは、その電界が図６（ａ）に示されるようにトナー７
の現像能力は絶縁性領域面２２に比べて高い。更に、こ
の部分は導電性であるためエッジ効果を抑えて画像濃度
を均一化するように作用する。According to this embodiment, areas are provided on the surface of the developing roller 1 where locally different developing biases act, and therefore the photosensitive drum 3 having the electrostatic latent image and the toner carrying surface are formed on the surface of the developing roller 1. When performing development by applying a bias between the toner and the developing roller 1, the toner transfer can be selectively controlled by the developing roller 1 whose surface is selectively charged, so that the above effect can be obtained. It is thought that this can be done. That is, as shown in FIG. 7A, a positive and negative electric field exceeding a threshold is acting on the toner 7 existing on the insulating region surface 22, and excessive toner adhesion is suppressed. On the other hand, the toner existing on the conductive region surface 21 has an electric field that is
The developing ability is higher than that of the insulating area surface 22. Furthermore, since this portion is conductive, it acts to suppress edge effects and make the image density uniform.
【００２３】更に詳述すると、画像濃度は低いものの線
図の再現性や階調性に優れているが、そのまま濃度を上
げると線図の再現性や階調性は損なわれてしまう性質の
ある、表面が絶縁性の現像ローラの特長と、その電極効
果によってベタ部の均一性に優れた濃度の高い画像を得
ることが出来るものの線図の再現性や階調性が劣る性質
の、表面が導電性の現像ローラの特長とを、本実施例に
かかる現像ローラ３は同時に合わせ持っている。More specifically, although the image density is low, it has excellent line drawing reproducibility and gradation, but if the density is increased as it is, the line drawing reproducibility and gradation will be impaired. Although it is possible to obtain high-density images with excellent uniformity of solid areas due to the features of the developing roller with an insulating surface and its electrode effect, it is possible to obtain high-density images with excellent uniformity of solid areas. The developing roller 3 according to this embodiment also has the characteristics of a conductive developing roller.
【００２４】次に、この現像ローラ１と感光体ドラム３
との間隙を２００μｍにしてトナー７の転移を調べたと
ころ、現像電界が２００Ｖを越えたときにトナー７の転
移が生じることが判った。即ち、現像電界の閾値はやは
り１Ｖ／μｍと一定になることが判った。現像間隙を更
に広げてテストしたところ、バイアス電圧を共に変更し
ながら５００μｍ程度までは画像を出すことが可能であ
ったが実用に耐えるものとするには３００μｍ以内とす
るのが望ましい。又、この３００μｍにおいては、現像
バイアスとして４５００Ｖを超えるＰ−Ｐのパルス電圧
を印加すると現像ローラ１と感光体ドラム３との間にリ
ークを生じた。即ち１５Ｖ／μｍ以下の電界とすること
が必要である。Next, the developing roller 1 and the photosensitive drum 3
When the transfer of the toner 7 was investigated with a gap of 200 μm, it was found that the transfer of the toner 7 occurred when the developing electric field exceeded 200V. That is, it has been found that the threshold value of the developing electric field remains constant at 1 V/μm. When the development gap was further widened and tested, it was possible to produce an image up to about 500 .mu.m while changing the bias voltage, but it is desirable to keep it within 300 .mu.m for practical use. Further, at this 300 μm, leakage occurred between the developing roller 1 and the photosensitive drum 3 when a P-P pulse voltage exceeding 4500 V was applied as a developing bias. That is, it is necessary to set the electric field to 15 V/μm or less.
【００２５】現像ローラ１の表面の絶縁性領域面２２の
巾Ｗが小さい、例えば図４（ａ）の現像ローラ１は感光
体より速い速度で移動することにより導電性領域面２１
の模様が画像に現われないようにすることが出来る。絶
縁性領域面２２の巾が導電性領域面２１の巾以上の場合
には感光体ドラム３とほぼ等速か若干速い速度で移動し
てやれば良い。いずれにしても１．０〜２．０倍、好ま
しくは１．０〜１．２倍の範囲で良好な結果を得ること
が出来た。The width W of the insulating area surface 22 on the surface of the developing roller 1 is small, for example, in the developing roller 1 shown in FIG.
It is possible to prevent the pattern from appearing in the image. When the width of the insulating region surface 22 is greater than the width of the conductive region surface 21, it is sufficient to move at approximately the same speed as the photoreceptor drum 3 or at a slightly faster speed. In any case, good results were obtained in the range of 1.0 to 2.0 times, preferably 1.0 to 1.2 times.
【００２６】次に、第２実施例について説明する。
この例は、感光体ドラム３としてＯＰＣを用い、地肌部
の表面電位を−１０Ｖ、画像部の表面電位を−８５０Ｖ
として、図４（ｂ）に示す表面形状を備えた現像ローラ
１を感光体ドラム３の表面と１００μｍの間隙をおいて
対向配置して正規現像を行なったものである。この現像
ローラ１表面の絶縁性領域面２２は、トナー供給ローラ
８でこすられて接地を基準とした電位が−２００Ｖにな
る量の電荷を保持し、これにより、正に帯電したトナー
７を担持した。このトナーの帯電量は約１０μＣ／ｇで
あった。そして、この現像ローラ１に現像バイアス印加
手段９で最高電位が＋２００Ｖに偏倚したＰ−Ｐ７５０
Ｖ、周波数５００Ｈｚの正弦波交流を印加した。Next, a second embodiment will be explained. In this example, an OPC is used as the photoreceptor drum 3, the surface potential of the background part is -10V, and the surface potential of the image part is -850V.
A developing roller 1 having a surface shape as shown in FIG. 4(b) was disposed facing the surface of the photosensitive drum 3 with a gap of 100 μm to perform regular development. The insulating area surface 22 on the surface of the developing roller 1 holds an amount of charge such that the potential is -200V with respect to the ground when rubbed by the toner supply roller 8, thereby carrying the positively charged toner 7. did. The charge amount of this toner was about 10 μC/g. Then, the developing roller 1 is supplied with a P-P750 whose highest potential is biased to +200V by the developing bias applying means 9.
V, a sinusoidal alternating current with a frequency of 500 Hz was applied.
【００２７】図８は、第１実施例についての図５と同様
に、接地を基準とした現像ローラ１の表面電位の時間的
変化を示したものであり、（ａ）は絶縁性領域面２２の
表面電位について、（ｂ）は導電性領域面２１の表面電
位について示している。これらの図中には、感光体ドラ
ム３表面の地肌部の表面電位のレベル（−１０Ｖ）及び
画像部の表面電位のレベル（−８５０Ｖ）を水平線とし
て夫々示している。図８（ａ）中の絶縁性領域面２２の
表面電位の時間的変化を示す正弦波連続線から判るよう
に、絶縁性領域面２２の表面電位は、現像バイアス印加
手段９による印加電圧が保持した電荷で−２００Ｖだけ
偏倚された電位になる。一方、導電性領域面２１の表面
電位は、図８（ｂ）中のこの領域面２１の表面電位の時
間的変化を示す正弦波連続線から判るように、現像バイ
アス印加手段９による印加電圧そのものになる。Similar to FIG. 5 for the first embodiment, FIG. 8 shows temporal changes in the surface potential of the developing roller 1 with reference to grounding, and (a) shows the change in the surface potential of the developing roller 1 with respect to the surface of the insulating region 22. (b) shows the surface potential of the conductive region surface 21. In these figures, the surface potential level (-10V) of the background portion of the surface of the photosensitive drum 3 and the surface potential level (-850V) of the image area are shown as horizontal lines, respectively. As can be seen from the continuous sinusoidal line showing the temporal change in the surface potential of the insulating region surface 22 in FIG. 8(a), the surface potential of the insulating region surface 22 is maintained by the voltage applied by the developing bias applying means 9. The resulting charge results in a potential biased by -200V. On the other hand, the surface potential of the conductive region surface 21 is the same as the voltage applied by the developing bias applying means 9, as can be seen from the sinusoidal continuous line showing the temporal change in the surface potential of the region surface 21 in FIG. 8(b). become.
【００２８】次に以上のように現像ローラ１表面の電位
が変化する場合の現像ローラ１表面と感光体ドラム３と
の間の電界について説明する。この電界は、第１実施例
と同様に、現像ローラ１表面が絶縁性領域面２２上と導
電性領域面２１上との何れであるかによって、更に、夫
々の領域面２２，２１について感光体ドラム３の画像部
と地肌部との何れに対向しているかによって異なる。Next, the electric field between the surface of the developing roller 1 and the photosensitive drum 3 when the potential on the surface of the developing roller 1 changes as described above will be explained. As in the first embodiment, this electric field is further applied to the photoreceptor for each area surface 22 and 21 depending on whether the surface of the developing roller 1 is on the insulating area surface 22 or the conductive area surface 21. It differs depending on whether the drum 3 faces the image area or the background area.
【００２９】図９は、これらのうち図８（ｂ）に示すよ
うな表面電位の時間的変化を生じる導電性領域面２１上
の電界を説明するためのものであり、図９（ａ）はこの
領域面２１が感光体ドラム３の画像部（未露光部）に対
向している場合の両者の電位差の時間的変化を示し、図
９（ｂ）はこの領域面２１が感光体ドラム３の非画像部
（露光部）に対向している場合の両者の電位差の時間的
変化を示す。又、図１０は図８（ａ）に示すような表面
電位の時間的変化を生じる絶縁性領域面２２上の電界を
説明するためのものであり、図１０（ａ）はこの領域面
２２が感光体ドラム３の画像部（露光部）に対向してい
る場合の両者の電位差の時間的変化を示し、図１０（ｂ
）はこの領域面２２が感光体ドラム３の非画像部（未露
光部）に対向している場合の両者の電位差の時間的変化
を示す。FIG. 9 is for explaining the electric field on the conductive region surface 21 that causes the temporal change in surface potential as shown in FIG. 8(b), and FIG. FIG. 9B shows a temporal change in the potential difference between the area surface 21 and the image area (unexposed area) of the photoreceptor drum 3. FIG. It shows the temporal change in the potential difference between the two when facing the non-image area (exposed area). Furthermore, FIG. 10 is for explaining the electric field on the insulating region surface 22 that causes the temporal change in surface potential as shown in FIG. 8(a). Figure 10(b) shows the temporal change in the potential difference between the photosensitive drum 3 when it faces the image area (exposed area).
) shows a temporal change in the potential difference between the area surface 22 and the non-image area (unexposed area) of the photosensitive drum 3 when the area surface 22 faces the non-image area (unexposed area).
【００３０】これらの図においては、電界が現像ローラ
１表面に担持されたトナー７あるいは感光体ドラム３の
表面に担持されたトナー７に静電気力を及ぼすものであ
ることから、上記第１実施例にかかる図６及び図７と同
様に、この静電気力の方向を区別するためにトナー７が
感光体ドラム３に向かう方向の電界に対応する上記電位
差を正、現像ローラ１に向かう方向の電界に対応する上
記電位差を負として表わしている。又上記の第１実施例
と同様の実験によって確認された、現像ローラ１上のト
ナー７が感光体ドラム３へ転移する上記電位差の閾値＋
１００Ｖのレベルと、感光体ドラム３上のトナー７が現
像ローラ１の方へ転移する電界の閾値−１００Ｖのレベ
ルとを水平線で示し、且つ、この閾値を越えてトナー７
の転移に寄与する電界に対応する部分を斜線で表してい
る。この例においても現像電界の閾値は１Ｖ／μｍであ
った。In these figures, since the electric field exerts an electrostatic force on the toner 7 carried on the surface of the developing roller 1 or the toner 7 carried on the surface of the photosensitive drum 3, Similarly to FIGS. 6 and 7, in order to distinguish the direction of this electrostatic force, the electric potential difference corresponding to the electric field in the direction in which the toner 7 is directed toward the photoreceptor drum 3 is positive, and the electric field in the direction in which the toner 7 is directed toward the developing roller 1 is positive. The corresponding potential difference is expressed as negative. Further, the threshold value of the potential difference at which the toner 7 on the developing roller 1 is transferred to the photoreceptor drum 3, which was confirmed by an experiment similar to that of the first embodiment, is +
The level of 100V and the threshold value of the electric field at which the toner 7 on the photoreceptor drum 3 is transferred toward the developing roller 1 -100V level are shown by horizontal lines, and the level of the toner 7 exceeding this threshold value is indicated by a horizontal line.
The part corresponding to the electric field that contributes to the transition of is indicated by diagonal lines. In this example as well, the threshold value of the developing electric field was 1 V/μm.
【００３１】現像ローラ１の導電性領域面２１上に存在
するトナー７は、感光体ドラム３の画像部と対向する場
合には図９（ａ）の斜線部で示されるように常に＋１０
０〜＋１０５０Ｖの正電界になっており、感光体ドラム
３の方向に転移するものと考えられ、感光体ドラム３の
地肌部と対向する場合には、図９（ｂ）の斜線部で示さ
れるようにトナーの転移に寄与する電界として、−１０
０〜−５４０Ｖの負電界と＋１００〜＋２１０Ｖの正電
界が交互に現われ、正電界のときは現像ローラ１から感
光体ドラム３へ、負電界のときは感光体ドラム３から現
像ローラ１へ転移するが、負電界による感光体ドラム３
から現像ローラ１への転移が生じている期間の方が充分
長く、且つ、転移力も大きいので、正電界で感光体ドラ
ムに転移するトナー７が生じたとしても再び現像ローラ
１へ転移してるものと考えられる。When the toner 7 existing on the conductive area surface 21 of the developing roller 1 faces the image area of the photosensitive drum 3, the toner 7 is always +10 as shown by the hatched area in FIG. 9(a).
It is a positive electric field of 0 to +1050V, and is thought to be transferred in the direction of the photoreceptor drum 3, and when facing the background part of the photoreceptor drum 3, it is shown by the hatched area in FIG. 9(b). As the electric field contributing to toner transfer, -10
A negative electric field of 0 to -540V and a positive electric field of +100 to +210V appear alternately, and when the electric field is positive, the electric field is transferred from the developing roller 1 to the photoreceptor drum 3, and when the electric field is negative, the electric field is transferred from the photoreceptor drum 3 to the developing roller 1. However, due to the negative electric field, the photoreceptor drum 3
The period during which the toner is transferred from to the developing roller 1 is sufficiently long and the transfer force is also large, so even if the toner 7 is transferred to the photoreceptor drum due to the positive electric field, it is transferred to the developing roller 1 again. it is conceivable that.
【００３２】同様に、現像ローラ１の絶縁性領域面２２
上に存在するトナー７は、感光体ドラム３の画像部と対
向する場合には、図１０（ａ）の斜線部で示されるよう
に常に＋１００Ｖ〜＋８５０Ｖの正電界になっており、
現像ローラ１から感光体ドラム３へ転移するが、この絶
縁性領域面２２が元々−２００Ｖに帯電しているので、
その転移力は上記の導電正領域面２１上に存在するトナ
ー７よりは小さいと考えられる。又、感光体ドラム３の
地肌部と対向する場合には、図１０（ｂ）の斜線部で示
すように、トナーの転移に寄与する電界として、−１０
０〜−７４０Ｖの負電界のみが現われるので、交互に転
移することはないと考えられる。Similarly, the insulating area surface 22 of the developing roller 1
When the toner 7 existing above faces the image area of the photoreceptor drum 3, it is always in a positive electric field of +100V to +850V, as shown by the hatched area in FIG. 10(a).
It is transferred from the developing roller 1 to the photosensitive drum 3, but since this insulating area surface 22 is originally charged to -200V,
The transfer force is considered to be smaller than that of the toner 7 existing on the conductive positive region surface 21 described above. In addition, when facing the background part of the photosensitive drum 3, as shown by the hatched area in FIG. 10(b), the electric field contributing to the toner transfer is -10
Since only a negative electric field of 0 to -740V appears, it is thought that there is no alternating transition.
【００３３】以上のように現像ローラ１に担持されたト
ナー７は現像ローラ１表面に形成された電界で選択的に
その転移が制御されるのである。As described above, the transfer of the toner 7 carried on the developing roller 1 is selectively controlled by the electric field formed on the surface of the developing roller 1.
【００３４】この例においても、表面が全てアルミニウ
ムである現像ローラ１を用い、同様の正弦波の電圧を現
像ローラ１に印加した場合に比し、地肌汚れがなく濃度
の高い画像が得られ、しかも線図の再現性も優れていた
。In this example as well, compared to the case where a developing roller 1 whose surface is entirely made of aluminum is used and a similar sinusoidal voltage is applied to the developing roller 1, a high-density image with no background stains can be obtained. Furthermore, the reproducibility of the line diagrams was also excellent.
【００３５】以上の第１、第２実施例は図４の（ｂ）に
示す表面形状を備えた現像ローラ１を用いたものである
が、図４（ａ），（Ｃ）に示す表面形状を備えた現像ロ
ーラ１を用い、第１実施例のパルス電圧や第２実施例の
正弦波交流電圧を印加して実験したところ、同様に、地
肌汚れがなく濃度の高い画像が得られ、しかも線図の再
現性も優れた画像を得ることが出来た。The first and second embodiments described above use the developing roller 1 having the surface shape shown in FIG. 4(b), but the developing roller 1 having the surface shape shown in FIGS. When an experiment was conducted using the developing roller 1 equipped with the following, applying the pulse voltage of the first embodiment and the sinusoidal AC voltage of the second embodiment, images with high density and no background stains were similarly obtained. We were able to obtain images with excellent line drawing reproducibility.
【００３６】又、上記の各実施例においては、従来の現
像ローラ１と比し現像部周辺のトナー７による汚染が少
ないことが判った。即ち、画質を良くすることができる
のに加え、装置周辺のトナー７による汚染も少なくする
ことが出来るという効果を得ることが出来る。Furthermore, in each of the above embodiments, it was found that there was less contamination by the toner 7 around the developing section compared to the conventional developing roller 1. That is, in addition to improving the image quality, it is also possible to reduce contamination caused by the toner 7 around the device.
【００３７】[0037]
【発明の効果】本発明によれば、静電潜像担持体上の電
位と、現像剤担持体上の電位と、電圧印加手段によって
形成される電界との相互関係で決定される電界により現
像剤の移動を制御し、これにより、静電潜像担持体上の
静電潜像に適量の現像剤を付着させるので、画像濃度が
高く、しかも線図の再現性や階調性にも優れた現像画像
を得ることが出来るという優れた効果がある。According to the present invention, development is performed by an electric field determined by the mutual relationship between the potential on the electrostatic latent image carrier, the potential on the developer carrier, and the electric field formed by the voltage applying means. By controlling the movement of the developer, an appropriate amount of developer is attached to the electrostatic latent image on the electrostatic latent image carrier, resulting in high image density and excellent line reproducibility and gradation. This has the excellent effect of being able to obtain a developed image with a high quality.
【図１】本発明の実施例の現像装置の全体概略を示す側
断面図である。FIG. 1 is a side sectional view schematically showing a developing device according to an embodiment of the present invention.
【図２】（ａ）はその現像ローラの一例の外観を示す斜
視図であり、（ｂ）はその外層部の拡大断面図である。FIG. 2(a) is a perspective view showing the appearance of an example of the developing roller, and FIG. 2(b) is an enlarged sectional view of the outer layer portion thereof.
【図３】絶縁性領域面近傍に形成される微小閉電界の電
気力線を示す説明図である。FIG. 3 is an explanatory diagram showing lines of electric force of a minute closed electric field formed near the surface of an insulating region.
【図４】（ａ）乃至（ｃ）は互いに異なる幅の絶縁性領
域面を備えた３つの現像ローラの表面を拡大した様子を
示す図である。FIGS. 4(a) to 4(c) are enlarged views of the surfaces of three developing rollers each having insulating area surfaces of different widths; FIGS.
【図５】第１実施例における現像ローラの表面電位の時
間的変化を示したものであり、（ａ）は絶縁性領域面に
ついての電位の変化を、（ｂ）は導電性領域面について
の電位の変化を示したものである。FIG. 5 shows temporal changes in the surface potential of the developing roller in the first example, where (a) shows the change in potential on the insulating region surface, and (b) shows the change in the potential on the conductive region surface. This shows the change in potential.
【図６】同実施例における導電性領域面上の現像電界の
説明図であり、（ａ）は感光体ドラム上の画像部に対向
する場合の時間的変化を、（ｂ）は感光体ドラム上の地
肌部に対向する場合の時間的変化を示しものである。FIG. 6 is an explanatory diagram of the developing electric field on the surface of the conductive region in the same example, in which (a) shows the temporal change when facing the image area on the photoreceptor drum, and (b) shows the development electric field on the surface of the photoreceptor drum. It shows the temporal change when facing the upper skin part.
【図７】同実施例における絶縁性領域面上の現像電界の
説明図であり、（ａ）は感光体上の画像部に対向する場
合の時間的変化を、（ｂ）は感光体上の地肌部に対向す
る場合の時間的変化を示しものである。FIG. 7 is an explanatory diagram of the developing electric field on the insulating region surface in the same example, where (a) shows the temporal change when facing the image area on the photoreceptor, and (b) shows the development electric field on the photoreceptor. This shows the temporal change when facing the skin.
【図８】第２実施例における現像ローラの表面電位の時
間的変化を示したものであり、（ａ）は絶縁性領域面に
ついての電位の変化を、（ｂ）は導電性領域面について
の電位の変化を示したものである。FIG. 8 shows temporal changes in the surface potential of the developing roller in Example 2, where (a) shows the change in potential on the insulating region surface, and (b) shows the change in the potential on the conductive region surface. This shows the change in potential.
【図９】同実施例における導電性領域面上の現像電界の
説明図であり、（ａ）は感光体ドラム上の画像部に対向
する場合の時間的変化を、（ｂ）は感光体ドラム上の地
肌部に対向する場合の時間的変化を示しものである。FIG. 9 is an explanatory diagram of the developing electric field on the surface of the conductive region in the same example, in which (a) shows the temporal change when facing the image area on the photoreceptor drum, and (b) shows the development electric field on the surface of the photoreceptor drum. It shows the temporal change when facing the upper skin part.
【図１０】同実施例における絶縁性領域面上の現像電界
の説明図であり、（ａ）は感光体上の画像部に対向する
場合の時間的変化を、（ｂ）は感光体上の地肌部に対向
する場合の時間的変化を示しものである。FIG. 10 is an explanatory diagram of the developing electric field on the surface of the insulating region in the same example, where (a) shows the temporal change when facing the image area on the photoreceptor, and (b) shows the development electric field on the photoreceptor. This shows the temporal change when facing the skin.
１ 現像ローラ ２ 現像装置 ３ 感光体ドラム ４ ブレード部材 ５ トナータンク ６ アジテータ ７ トナー ８ トナー供給ローラ ９ 現像バイアス印加手段 ２１ 導電性領域面 ２２ 絶縁性領域面 1 Developing roller 2 Developing device 3 Photoreceptor drum 4 Blade member 5 Toner tank 6 Agitator 7 Toner 8 Toner supply roller 9 Development bias application means 21 Conductive area surface 22 Insulating area surface
Claims (15)
剤担持体と静電潜像担持体が互いに対向する現像部にお
いて現像を行なう現像装置において、該現像剤担持体と
して表面に多数の電界配置を形成した現像剤担持体と、
該現像部に電界を形成するための電圧印加手段とを有し
、該静電潜像担持体上の電位と、該現像剤担持体上の電
位と、該電圧印加手段によって形成される電界との相互
関係で決定される電界により現像剤の移動を制御するこ
とを特徴とする現像装置。Claims: 1. A developing device in which a developer is carried on a developer carrier and development is carried out in a developing section where the developer carrier and the electrostatic latent image carrier face each other; a developer carrier in which a large number of electric field arrangements are formed;
a voltage applying means for forming an electric field in the developing section, the potential on the electrostatic latent image carrier, the potential on the developer carrier, and the electric field formed by the voltage applying means; A developing device characterized in that the movement of developer is controlled by an electric field determined by the mutual relationship between the following.
することを特徴とする請求項１記載の現像装置。2. The developing device according to claim 1, wherein the developer is supported by the plurality of electric field arrangements.
が交互電界であることを特徴とする請求項１又は２記載
の現像装置。3. The developing device according to claim 1, wherein the electric field formed by the voltage applying means is an alternating electric field.
上記静電潜像担持体との間を転移、逆転移するように現
像剤の移動を制御することを特徴とする請求項１、２又
は３記載の現像装置。4. In the developing section, movement of the developer is controlled so as to transfer and reverse transfer between the developer carrier and the electrostatic latent image carrier. 3. The developing device according to 2 or 3.
を互いに相対移動させることを特徴とする請求項１、２
、３又は４記載の現像装置。5. Claims 1 and 2, wherein the developer carrier and the electrostatic latent image carrier are moved relative to each other.
The developing device according to , 3 or 4.
体表面との間隙が、上記現像剤担持体上に担持される現
像剤の層厚以下であることを特徴とする請求項１、２、
３、４又は５記載の現像装置。6. A claim characterized in that a gap between the surface of the developer carrier and the surface of the electrostatic latent image carrier is equal to or less than the layer thickness of the developer supported on the developer carrier. 1, 2,
The developing device according to 3, 4 or 5.
体表面との間隙が、上記現像剤担持体上に担持される現
像剤の層厚よりも大きいことを特徴とする請求項１、２
、３、４又は５記載の現像装置。7. A claim characterized in that the gap between the surface of the developer carrier and the surface of the electrostatic latent image carrier is larger than the layer thickness of the developer supported on the developer carrier. 1, 2
, 3, 4 or 5.
表面の隣りあう領域と電位が異なる、多数の微細領域か
らなり、該微細領域間に閉電界が形成されることを特徴
とする請求項１、２、３、４、５、６又は７記載の現像
装置。8. The plurality of electric field arrangements are made up of a plurality of microscopic regions having different potentials from adjacent regions on the surface of the developer carrier, and a closed electric field is formed between the microscopic regions. The developing device according to claim 1, 2, 3, 4, 5, 6 or 7.
像担持体と対向する現像部に搬送して現像を行なう現像
方法において、該現像部内の該現像剤担持体表面に、電
荷を保持して所定電位に帯電された第１の領域と該第１
の領域よりも低い電位の第２の領域とを混在させるとと
もに、該現像部に電圧印加手段で電界を形成し、該第１
の領域上には、該第１の領域に保持されている電荷、該
静電潜像担持体上の電位及び該電圧印加手段による電界
により、第２の領域上とは異なる現像電界を形成するこ
とを特徴とする現像方法。9. A developing method in which a developer is carried on a developer carrier and transported to a developing section facing an electrostatic latent image carrier to perform development, wherein the developer is deposited on the surface of the developer carrier in the developing section. , a first region that holds charge and is charged to a predetermined potential;
A second region having a lower potential than the first region is mixed, and an electric field is formed in the developing section by a voltage applying means.
A developing electric field different from that on the second area is formed on the area by the charges held in the first area, the potential on the electrostatic latent image carrier, and the electric field by the voltage applying means. A developing method characterized by:
に形成される電界によって、現像剤担持体上に現像剤を
担持することを特徴とする請求項９記載の現像方法。10. The developing method according to claim 9, wherein the developer is supported on the developer carrier by an electric field formed between the first region and the second region.
であることを特徴とする請求項９又は１０記載の現像方
法。11. The developing method according to claim 9, wherein the electric field produced by the voltage applying means is an alternating electric field.
持体表面との間隙が、上記現像剤担持体上に担持される
現像剤の層厚よりも大きいことを特徴とする請求項９、
１０又は１１記載の現像方法。12. A claim characterized in that the gap between the surface of the developer carrier and the surface of the electrostatic latent image carrier is larger than the layer thickness of the developer supported on the developer carrier. 9,
10 or 11. The developing method according to 10 or 11.
電性領域とで構成し、該絶縁性領域を上記第１の領域と
して用い、該導電性領域を上記第２の領域として用いる
ことを特徴とする請求項９、１０、１１又は１２記載の
現像方法。13. The surface of the developer carrier is composed of an insulating region and a conductive region, the insulating region is used as the first region, and the conductive region is used as the second region. The developing method according to claim 9, 10, 11 or 12, characterized by:
擦帯電によって電荷を保持せしめることを特徴とする請
求項１３記載の現像方法。14. The developing method according to claim 13, wherein the insulating region on the surface of the developer carrier is caused to retain electric charge by triboelectric charging.
とを互いに相対移動させることを特徴とする請求項９、
１０、１１、１２、１３又は１４記載の現像方法。15. Claim 9, wherein the developer carrier and the electrostatic latent image carrier are moved relative to each other.
10, 11, 12, 13 or 14.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03015778A JP3078337B2 (en) | 1990-04-10 | 1991-01-16 | Developing method and apparatus |
| DE4128942A DE4128942C2 (en) | 1991-01-16 | 1991-08-30 | Development device which is provided in an image forming device |
| US07/753,234 US5239344A (en) | 1991-01-16 | 1991-08-30 | Developing roller having insulating and conductive areas |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-94268 | 1990-04-10 | ||
| JP9426890 | 1990-04-10 | ||
| JP03015778A JP3078337B2 (en) | 1990-04-10 | 1991-01-16 | Developing method and apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04212183A true JPH04212183A (en) | 1992-08-03 |
| JP3078337B2 JP3078337B2 (en) | 2000-08-21 |
Family
ID=26351983
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03015778A Expired - Lifetime JP3078337B2 (en) | 1990-04-10 | 1991-01-16 | Developing method and apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3078337B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5965329A (en) * | 1996-08-05 | 1999-10-12 | Canon Kabushiki Kaisha | Method of manufacturing a developing agent bearing member |
-
1991
- 1991-01-16 JP JP03015778A patent/JP3078337B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5965329A (en) * | 1996-08-05 | 1999-10-12 | Canon Kabushiki Kaisha | Method of manufacturing a developing agent bearing member |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3078337B2 (en) | 2000-08-21 |
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