JPH04347878A - Developing device - Google Patents
Developing deviceInfo
- Publication number
- JPH04347878A JPH04347878A JP3151119A JP15111991A JPH04347878A JP H04347878 A JPH04347878 A JP H04347878A JP 3151119 A JP3151119 A JP 3151119A JP 15111991 A JP15111991 A JP 15111991A JP H04347878 A JPH04347878 A JP H04347878A
- Authority
- JP
- Japan
- Prior art keywords
- developing
- latent image
- toner
- developing device
- image 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.)
- Withdrawn
Links
- 238000011161 development Methods 0.000 claims abstract description 51
- 230000005684 electric field Effects 0.000 claims abstract description 21
- 238000001514 detection method Methods 0.000 claims description 4
- 230000007613 environmental effect Effects 0.000 claims description 4
- 230000018109 developmental process Effects 0.000 description 47
- 108091008695 photoreceptors Proteins 0.000 description 25
- 238000006073 displacement reaction Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000011144 upstream manufacturing Methods 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
Landscapes
- Magnetic Brush Developing In Electrophotography (AREA)
- Developing For Electrophotography (AREA)
- Dry Development In 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、ファ
クシミリ、プリンター等の静電記録装置に係り、詳しく
は、潜像担持体表面に現像剤やトナーを搬送する、現像
装置の現像剤搬送手段に関するものである。[Field of Industrial Application] The present invention relates to electrostatic recording devices such as electrophotographic copying machines, facsimiles, printers, etc., and more specifically, the present invention relates to electrostatic recording devices such as electrophotographic copying machines, facsimiles, printers, etc. This relates to conveyance means.
【０００２】0002
【従来の技術】従来の現像装置においては、現像剤担持
部材である現像スリーブを回転し、現像スリーブ表面に
担持した現像剤（一成分現像方式においてはトナー、二
成分現像方式においてはトナー及びキャリア）を潜像担
持体である感光体との対向部の現像領域に搬送して感光
体上の潜像の現像に供し、感光体に転写しなかった現像
剤をそのまま現像スリーブで現像装置内に回収し、新た
に現像剤を現像スリーブに担持して現像領域に搬送して
いた。又、このような現像装置においては、現像スリー
ブを導電性材料で構成し、該スリーブに電源装置から現
像バイアスを印加して該スリーブを潜像担持体に対する
対向電極として用いて現像を行なっていた。[Prior Art] In a conventional developing device, a developing sleeve, which is a developer carrying member, is rotated, and the developer carried on the surface of the developing sleeve (toner in a one-component developing system, toner and carrier in a two-component developing system) is rotated. ) is conveyed to a developing area opposite to the photoreceptor, which is a latent image carrier, to develop the latent image on the photoreceptor, and the developer that has not been transferred to the photoreceptor is directly transferred to the developing device using a developing sleeve. The developer was collected, and the developer was newly carried on a developing sleeve and conveyed to the developing area. In addition, in such a developing device, the developing sleeve is made of a conductive material, a developing bias is applied to the sleeve from a power supply, and the sleeve is used as a counter electrode to the latent image carrier to perform development. .
【０００３】0003
【発明が解決しようとする課題】ところが、上記構成に
よれば現像スリーブが回転することにより、現像スリー
ブとこれを支持する現像装置側板間にトナーが進入し、
トナーが擦れてトナー固着等が起こり、画像に悪影響を
及ぼしていた。又、現像スリーブ内に磁石ローラを内蔵
したものにおいては、該磁石ローラの磁界を現像スリー
ブが横切ることによって渦電流が発生し、これにより現
像スリーブのトルクの増大や現像スリーブが熱を帯びて
トナーが現像装置内で溶けてしまうこともあった。又、
画像品質を左右する、地汚れ防止、潜像の低濃度部の再
現性、潜像の中電位部の再現性（所謂中間調の再現性）
、高濃度の再現性等の夫々はこれを良好にするのに有利
な現像電界が異っている。ところが、上記構成によれば
導電性材料からなる一体の現像スリーブに現像バイアス
を印加するので、対向電極と潜像の電位差である現像電
界が現像領域内で一通りに決定される為に、これら全て
を満足させることが出来ず、結局、画質の優劣に最も影
響をおよぼす地汚れを防止できる現像特性を得ることを
優先して現像バイアス値を設定せざるを得ずにいつくか
の再現性については不十分な点が残されていた。そこで
、例えば、接触現像方式を採用する現像装置と非接触現
像方式を採用する現像装置というように、互いに現像特
性が異なる現像装置を併用して所謂γ補正を行なうこと
も提案されているが、これによれば装置が大型化すると
いう不具合が生じていた。更に、二成分現像方式の現像
装置の場合、現像領域通過後の現像スリーブ上には現像
領域進入前の略４０％のトナーが現像に使用されずに残
っており、潜像担持体に対するトナー供給効率が悪く、
画像形成動作の高速化に対応するには現像剤中のトナー
濃度を高めたり現像スリーブの回転速度を高速化する必
要があるので、トナー飛散や騒音が発生していた。
一成分現像方式の現像装置においても画像形成動作の高
速化に対応するには上記トナー供給効率が不十分であり
、現像スリーブ上のトナー層厚を厚くしたり現像スリー
ブの回転速度の高速化を行なう必要があるので、トナー
飛散や騒音が発生していた。現像スリーブの回転数を高
速に設定したり、二成分現像剤における現像剤のトナー
濃度を高めに設定し或いは一成分現像剤における現像ス
リーブ上のトナー層を厚く設定して、トナー供給率を高
めている現像装置においては、例えば、感光体の特性が
変化してトナーが付着しやすい電位になったときや、湿
度が比較的高い為にトナーの帯電量（Ｑ／Ｍ）が低下し
てトナー供給率が高まったときには、潜像に対する過剰
のトナー供給になって逆に画質が劣化してしまうとこと
もあった。本発明は以上の問題点に鑑みなされたもので
あり、第１の目的は現像スリーブ等の現像剤担持部材を
回転させずに現像剤を現像領域に搬送することが出来る
現像装置を提供することであり、第２の目的は簡易な構
成で良好な現像特性を得ることが出来る現像装置を提供
することであり、第３の目的は潜像担持体に対するトナ
ー供給効率を向上させた現像装置を提供することであり
、第４の目的は、潜像担持体に対するトナー供給率を変
化させることが出来る現像装置を提供することである。However, according to the above structure, as the developing sleeve rotates, toner enters between the developing sleeve and the side plate of the developing device that supports it.
The toner rubbed and toner sticking occurred, which adversely affected the image. In addition, in a developing sleeve with a built-in magnetic roller, eddy currents are generated when the developing sleeve crosses the magnetic field of the magnetic roller, which increases the torque of the developing sleeve and heats up the developing sleeve, causing toner to flow. sometimes melted inside the developing device. or,
Prevention of background smearing, reproducibility of low-density areas of the latent image, and reproducibility of medium-potential areas of the latent image (so-called halftone reproducibility), which affect image quality.
, high density reproducibility, etc., each of which has a different development electric field that is advantageous for improving the reproducibility. However, according to the above configuration, since a developing bias is applied to the integrated developing sleeve made of a conductive material, the developing electric field, which is the potential difference between the counter electrode and the latent image, is determined uniformly within the developing area. We were unable to satisfy all of the requirements, and in the end, we had no choice but to set the development bias value with priority on obtaining development characteristics that can prevent background smearing, which has the greatest impact on image quality. There were still some deficiencies left. Therefore, it has been proposed to perform so-called γ correction by using developing devices with different development characteristics, such as a developing device that uses a contact developing method and a developing device that uses a non-contact developing method. According to this, a problem arises in that the device becomes larger. Furthermore, in the case of a two-component developing type developing device, approximately 40% of the toner before entering the developing area remains on the developing sleeve after passing through the developing area without being used for development, and the toner supply to the latent image carrier is Inefficient,
In order to cope with faster image forming operations, it is necessary to increase the toner concentration in the developer and to increase the rotational speed of the developing sleeve, resulting in toner scattering and noise. Even in a one-component developing type developing device, the toner supply efficiency described above is insufficient to cope with the increased speed of image forming operations. This caused toner scattering and noise. To increase the toner supply rate, set the rotation speed of the developing sleeve to a high speed, set the toner concentration of the developer high in a two-component developer, or set the toner layer on the developing sleeve thick in a single-component developer. For example, when the characteristics of the photoconductor change and the potential becomes such that toner tends to adhere, or when the humidity is relatively high, the amount of charge (Q/M) of the toner decreases and the toner is damaged. When the supply rate increases, excessive toner is supplied to the latent image, resulting in deterioration of image quality. The present invention has been made in view of the above problems, and the first object is to provide a developing device that can transport developer to a developing area without rotating a developer carrying member such as a developing sleeve. The second objective is to provide a developing device that can obtain good developing characteristics with a simple configuration, and the third objective is to provide a developing device that improves the efficiency of toner supply to the latent image carrier. A fourth object is to provide a developing device that can change the toner supply rate to the latent image carrier.
【０００４】0004
【課題を解決するための手段】上記第１の目的を達成す
るために、請求項１の発明は、装置内から露出して潜像
担持体表面と対向する現像領域に装置内の現像剤を搬送
する現像剤搬送手段を超音波搬送部材を用いて構成し、
該現像剤搬送手段の該現像領域に在る部分に導電性の対
向電極を設けたことを特徴とするものである。上記第２
の目的を達成するために、請求項２の発明は、請求項１
の現像装置において、上記現像領域における上記潜像担
持体表面の移動方向にならべて上記対向電極を互いに絶
縁状態で複数設け、該複数の対向電極に電圧を印加する
電源装置を、該複数の対向電極のうち少なくとも２以上
が互いに異なる強度の現像電界を形成するように構成し
たことを特徴とするものである。上記第２及び第３の目
的を達成するために、請求項３の発明は、請求項２の画
像形成装置において、上記電源装置を、上記潜像担持体
表面の移動方向下流側に設けられた上記対向電極ほど強
度の大きな現像電界を形成するように構成したことを特
徴とするものである。上記第４の目的を達成するために
、請求項６の発明は、請求項１の現像装置において、上
記現像領域における上記潜像担持体表面の移動方向にな
らべて上記対向電極を互いに絶縁状態で複数設け、該対
向電極のうちの少なくとも１以上に、他の対向電極への
電圧印加状態のときに電圧遮断状態にし得るスイッチ手
段を設け、該スイッチ手段を制御する制御手段を設けた
ことを特徴とするものである。[Means for Solving the Problems] In order to achieve the above first object, the invention of claim 1 is directed to discharging the developer in the device into a developing area exposed from inside the device and facing the surface of a latent image carrier. A developer conveying means for conveying is configured using an ultrasonic conveying member,
The present invention is characterized in that a conductive counter electrode is provided in a portion of the developer transport means located in the development area. 2nd above
In order to achieve the objective of claim 2, the invention of claim 1
In the developing device, a plurality of the opposed electrodes are provided insulated from each other in the direction of movement of the surface of the latent image carrier in the development area, and a power supply device for applying a voltage to the plurality of opposed electrodes is provided between the plurality of opposed electrodes. The present invention is characterized in that at least two of the electrodes are configured to form developing electric fields of mutually different intensities. In order to achieve the second and third objects, the invention according to claim 3 provides the image forming apparatus according to claim 2, in which the power supply device is provided downstream in the moving direction of the surface of the latent image carrier. The present invention is characterized in that the opposite electrode is configured to form a developing electric field with greater strength. In order to achieve the fourth object, in the developing device according to claim 1, the opposing electrodes are insulated from each other in the developing area in the direction of movement of the surface of the latent image carrier. A plurality of counter electrodes are provided, and at least one of the counter electrodes is provided with a switch means that can turn off a voltage when a voltage is applied to another counter electrode, and a control means is provided for controlling the switch means. That is.
【０００５】[0005]
【作用】請求項１の発明は、現像剤搬送手段として超音
波搬送手段を用い、これにより、現像剤担持部材を回転
させることなく現像剤の現像領域へ搬送し、該現像剤搬
送手段の該現像領域に在る部分に設けた導電性の対向電
極で現像領域に現像電界を形成し、これにより、該現像
剤を潜像に応じて付着させて現像を行なうように作用す
るものである。請求項２の発明は、上記現像領域におけ
る上記潜像担持体表面の移動方向にならべて上記対向電
極を互いに絶縁状態で複数設け、且つ、電源装置により
該複数の対向電極のうち少なくとも２以上が互いに異な
る強度の現像電界を形成し、これにより、２種以上の異
なる現像特性による現像を行なうように作用するもので
ある。請求項３の発明は、上記電源装置により上記潜像
担持体表面の移動方向下流側に設けられた上記対向電極
ほど強度の大きな現像電界を形成し、これにより、現像
領域を通過する間に比較的上流側の対向電極で一部のト
ナーを潜像担持体側に供給してトナー存在率が低下した
状態で現像を行なう、比較的下流側の対向電極において
も、潜像担持体側への充分なトナー供給を行ない得るよ
うに作用するものである。請求項６の発明は、上記現像
領域における上記潜像担持体表面の移動方向にならべて
互いに絶縁状態で設けた複数の対向電極のうちの少なく
とも１以上に、他の対向電極への電圧印加状態のときに
電圧遮断状態にし得るスイッチ手段を設け、該スイッチ
手段を制御手段で制御して、対向電極効果を発揮しえる
対向電極の個数を変え、これにより、有効な現像領域幅
を変えてトナー供給率を変化させるように作用するもの
である。[Operation] The invention according to claim 1 uses an ultrasonic conveying means as the developer conveying means, whereby the developer is conveyed to the developing area without rotating the developer carrying member, and the developer is conveyed to the developing area of the developer carrying member. A developing electric field is formed in the developing area by a conductive counter electrode provided in a portion in the developing area, and this acts to cause the developer to adhere to the latent image and perform development. The invention according to claim 2 is characterized in that a plurality of the opposing electrodes are arranged in a mutually insulated state in a direction in which the surface of the latent image carrier is moved in the developing area, and at least two or more of the plurality of opposing electrodes are connected by a power supply device. They form developing electric fields of mutually different intensities, thereby acting to perform development with two or more different developing characteristics. The invention according to claim 3 is characterized in that the power supply device forms a developing electric field that is stronger as the opposing electrode is provided on the downstream side in the moving direction of the surface of the latent image carrier. The counter electrode on the relatively downstream side supplies some toner to the latent image carrier side to perform development with the toner abundance ratio reduced. It functions to supply toner. The invention according to claim 6 provides a method of applying a voltage to at least one of a plurality of opposing electrodes arranged in a mutually insulated state in the direction of movement of the surface of the latent image carrier in the developing area, and applying a voltage to the other opposing electrodes. A switch means is provided which can set the voltage to a cutoff state when It acts to change the supply rate.
【０００６】[0006]
【実施例】本発明を画像形成装置である電子写真複写機
の現像装置に適用した実施例について説明する。図１（
ａ）において、像担持体であるドラム状の感光体１が時
計向きに回転駆動される。感光体ドラム１の周囲には現
像装置１６の他に図示しない、感光体表面を例えば正極
性の所定電位に一様に帯電するための帯電器、照明装置
で照射された複写すべき原稿からの反射光を感光体上に
結像照射して静電潜像を形成するための光学系、現像装
置１６で静電潜像が現像されて形成された感光体上のト
ナー像を給紙装置から送られてきた転写紙に転写するた
めの転写装置、転写後の感光体ドラム１上の残留トナー
を除去するクリーニング装置、感光体ドラム１を除電す
る除電装置などが配設されている。この例における現像
装置１６は、負極性に帯電させる一成分非磁性トナーを
用いた一成分現像方式を採用しており、装置内に現像ロ
ーラ１６１、トナーを負極性に摩擦帯電させると共に現
像ローラ上で薄層化する薄層化ブレード１６２、現像ロ
ーラ１６１表面にトナーを供給する弾性回転ローラ１６
７、及び、トナーを撹拌、搬送するためのアジテータ１
６３を備えている。このアジテータ１６３は回転トルク
が図示しない検出器で検出され、このトルクが所定以下
に低減したときに現像装置１６のケーシングで形成して
いるトナーホッパー部内のトナーが無くなったことを検
知するトナーエンド検知にも用いられている。尚、この
例は現像ローラ表面と感光体表面とがトナー層の厚みよ
りも大きな間隔をおいて対向し、非接触現像を行なうも
のであるが、現像ローラ表面上のトナー層を感光体表面
に接触させながら現像を行なう接触現像にしても良い。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing device of an electrophotographic copying machine, which is an image forming apparatus, will be described. Figure 1 (
In a), the drum-shaped photoreceptor 1, which is an image carrier, is rotated clockwise. Around the photoreceptor drum 1, in addition to the developing device 16, there is a charger (not shown) for uniformly charging the surface of the photoreceptor to a predetermined potential of positive polarity, for example, and a charger (not shown) for uniformly charging the surface of the photoreceptor to a predetermined potential of positive polarity, and a charger (not shown) for uniformly charging the surface of the photoreceptor to a predetermined potential of positive polarity. An optical system for forming an electrostatic latent image by irradiating reflected light onto the photoconductor, and a toner image on the photoconductor formed by developing the electrostatic latent image in the developing device 16 from the paper feeding device. A transfer device for transferring the toner onto a transferred transfer paper, a cleaning device for removing residual toner on the photoreceptor drum 1 after the transfer, a static eliminator for removing static from the photoreceptor drum 1, and the like are provided. The developing device 16 in this example employs a one-component developing method using a one-component non-magnetic toner that is charged to a negative polarity. a thinning blade 162 that thins the layer with the elastic rotating roller 16 that supplies toner to the surface of the developing roller 161;
7, and an agitator 1 for stirring and transporting toner
It is equipped with 63. This agitator 163 detects rotational torque with a detector (not shown), and when this torque is reduced to a predetermined value or less, toner end detection detects that the toner in the toner hopper section formed by the casing of the developing device 16 has run out. It is also used in In this example, the surface of the developing roller and the surface of the photoconductor face each other with an interval larger than the thickness of the toner layer, and non-contact development is performed. Contact development may be used, in which development is performed while contacting.
【０００７】現像ローラ１６１は現像ローラ軸１６０上
に超音波搬送部材を設けて構成されている。この超音波
搬送部材は、固定現像ローラ軸１６０上の複数の電極１
６４と、その外側の圧電部材１６５（例えば、圧電セラ
ミックス）と、更にその外側の弾性部材１６６とからな
っている。この複数の電極１６４は図示しない電源装置
に接続されており、この電源装置から後述する動作原理
に基づいて複数の定在波が印加される。そして、現像ロ
ーラ１６１の周面のうち感光体ドラム１と対向する現像
領域に在る部分には図１（ｂ）に示すように互い絶縁さ
れている例えば４つの対向電極１６１ａ，１６１ｂ，１
６１ｃ，１６１ｄ（以下、感光体ドラム移動方向上流側
から順に第１〜第４対向電極という）が設けられている
。この例では各対向電極は感光体ドラム表面移動方向の
幅が互いに同一になるように設定されている。そして、
それぞれの対向電極に独立に異なる電圧を印加し得るよ
うに第１乃至第４電源２０ａ，２０ｂ，２０ｃ，２０ｄ
が接続されている。このうち感光体移動方向で最上流側
の第１対向電極１６１ａ以外の対向電極１６１ｂ，１６
１ｃ，１６１ｄについては後述する使用対向電極制御に
よって現像動作中にも電圧印加を行なわないように出来
るように電源２０ｂ，２０ｃ，２０ｄとの間にスイッチ
手段２１ｂ，２１ｃ，２１ｄが設けられている。この例
では各電源２０ａ，２０ｂ，２０ｃ，２０ｄは、感光体
表面移動方向下流側の対向電極に現像バイアスを印加す
るものほど小さな電位を印加するように設定してある。
これは後述するように同下流側の対向電極ほど大きな現
像電界を形成するようにするためである。従って、正確
には現像電界が潜像の電位と対向電極の電位との電位差
及び潜像担持体表面と対向電極との距離等で決定されて
いることから、図１（ｂ）に示すように感光体ドラム１
と現像ローラ１６１の曲率が異なることにより、該距離
が各対向電極について互いに異なるこの例においては、
この距離の影響も考慮して現像バイアスを設定すべきで
あるが、ここでは、この距離の影響を無視できるものと
する。このように現像ローラ１６１の周面に互いに絶縁
されている複数の対向電極を設けるには、図１（ａ）に
示す弾性部材１６６を絶縁性材料で構成し、これに対向
電極１６１ａ，１６１ｂ，１６１ｃ，１６１ｄを間隔を
あけて埋め込むようにしても良いし、弾性部材１６６が
導電性材料からなる場合にはその外側に絶縁体層を設け
この絶縁体層に同様にして対向電極１６１ａ，１６１ｂ
，１６１ｃ，１６１ｄを埋め込むようにしても良い。The developing roller 161 is constructed by providing an ultrasonic conveying member on the developing roller shaft 160. This ultrasonic conveying member includes a plurality of electrodes 1 on the fixed developing roller shaft 160.
64, a piezoelectric member 165 (for example, piezoelectric ceramic) on the outside thereof, and an elastic member 166 on the outside thereof. The plurality of electrodes 164 are connected to a power supply device (not shown), and a plurality of standing waves are applied from this power supply device based on the operating principle described later. As shown in FIG. 1(b), for example, four counter electrodes 161a, 161b, 1 are provided on a portion of the circumferential surface of the developing roller 161 located in a developing area facing the photoreceptor drum 1.
61c and 161d (hereinafter referred to as first to fourth opposing electrodes in order from the upstream side in the direction of movement of the photoreceptor drum) are provided. In this example, each of the opposing electrodes is set to have the same width in the direction of movement of the photoreceptor drum surface. and,
First to fourth power supplies 20a, 20b, 20c, 20d so as to be able to independently apply different voltages to each counter electrode.
is connected. Among these, the counter electrodes 161b and 16 other than the first counter electrode 161a on the most upstream side in the photoreceptor movement direction
As for 1c and 161d, switch means 21b, 21c, and 21d are provided between them and power supplies 20b, 20c, and 20d so that voltage application is not performed even during the developing operation by controlling the counter electrode used, which will be described later. In this example, each of the power supplies 20a, 20b, 20c, and 20d is set to apply a smaller potential to the opposite electrode located downstream in the direction of movement of the surface of the photoreceptor that applies a developing bias. This is because, as will be described later, a larger developing electric field is formed at the opposite electrode on the downstream side. Therefore, to be precise, since the developing electric field is determined by the potential difference between the potential of the latent image and the potential of the counter electrode, the distance between the surface of the latent image carrier and the counter electrode, etc., as shown in FIG. 1(b), Photosensitive drum 1
In this example, the distances are different for each opposing electrode due to the different curvatures of the developing roller 161 and the developing roller 161.
Although the developing bias should be set in consideration of the influence of this distance, it is assumed here that the influence of this distance can be ignored. In order to provide a plurality of opposing electrodes that are insulated from each other on the circumferential surface of the developing roller 161, the elastic member 166 shown in FIG. 161c and 161d may be embedded with a space between them, or if the elastic member 166 is made of a conductive material, an insulating layer is provided on the outside thereof and the counter electrodes 161a and 161b are similarly formed on this insulating layer.
, 161c, and 161d may be embedded.
【０００８】ここで、本実施例の超音波搬送部材で用い
ている超音波振動を駆動源とする搬送動作の原理につい
て説明する。超音波とは、人が聞くことが可能な周波数
５０Ｈｚ〜２０ＫＨｚを越える周波数の空気の弾性振動
であり、広義には空気の可聴音を除く気体、液体、固体
の弾性振動全般を意味する。この場合は固体の弾性振動
に相当する。一般的な動作原理としては、厚さＴ、幅Ｗ
、長さＬ、密度ρ、ヤング率Ｙの矩形板は、両端（Ｘ＝
０，Ｙ＝Ｌ）に於ける変位が等しい場合、 Ｔ《
Ｌ ， Ｗ《Ｌ
…（１）として、厚さＴ方向の変位ξ１は、
ξ１＝ξ０Ｓｉｎ（ｎＸ）・Ｓｉｎ（ω０ｔ）
…（２）
である。
ｎ４＝１２ω０２ρ／（ＹＴ２）
…（３） ｎＬ＝２πＳ
Ｓ＝１，２，３
…（４） ｌ＝Ｌ／Ｓ
ω０＝（２π／ｌ）２×Ｔ（Ｙ／１２ρ）１／２
…（５）
ｌは波長である。同様に、位置的に且つ時間的にπ
／２の位相を変えると、 ξ２＝ξ０ｃｏｓ（ｎ
Ｘ）×ｃｏｓ（ω０ｔ）
…（６） この２つの振動が加え合わ
されると、撓み振動の進行波が得られる。
ξ＝ξ１＋ξ２＝ξ０ｃｏｓ（ｎＸ−ω０ｔ）
…（７
） 位相速度ｖは、
ｖ＝ω０／ｎ＝（２π／ｌ）Ｔ（Ｙ／１２ρ）
１／２ …（８）と求
まる。この振動は中性面に対するものであり、厚さＴの
表面においては（中性面からＴ／２離れた位置では）、
ζ＝ξ０ｎ（Ｔ／２）×ｓｉｎ（ｎＸ−ω０ｔ
）＝πξ０（Ｔ／ｌ）×ｓｉｎ（ｎＸ−ω０ｔ）
…（９）
で示される横方向（長さＬ方向）の変位が生じる。
（７）式と（９）式は表面上の質点が、縦方向と横方向
の比を１：πＴ／ｌとする楕円運動をしていることを示
す。縦方向変位ξが最大の場合（ｎＸ＝ω０ｔ）、横方
向変位ζは最小である。横方向変位ζの速度Ｕも最大と
なり、次式となる。
Ｕ＝ｄζ／ｄｔ＝−πω０ξ０（Ｔ／ｌ）×ｃ
ｏｓ（ｎＸ−ω０ｔ） Ｕｍａｘ＝−πω０ξ０
Ｔ／ｌ
…（１０）進行波であるから縦方
向変位ξの最大点は位相速度ｖで移行するが、その頂点
に接触する物体は上式の速度で一定方向に移動する。[0008] Here, the principle of the transport operation using ultrasonic vibration as a driving source used in the ultrasonic transport member of this embodiment will be explained. Ultrasonic waves are elastic vibrations of air with a frequency exceeding 50 Hz to 20 KHz that can be heard by humans, and in a broad sense, it refers to all elastic vibrations of gases, liquids, and solids, excluding audible sounds of air. In this case, it corresponds to elastic vibration of a solid. The general principle of operation is that the thickness T, width W
, length L, density ρ, Young's modulus Y, both ends (X=
0, Y=L) are equal, then T《
L, W《L
...(1), the displacement ξ1 in the thickness T direction is ξ1=ξ0Sin(nX)・Sin(ω0t)
...(2)
It is. n4=12ω02ρ/(YT2)
...(3) nL=2πS
S=1,2,3
...(4) l=L/S
ω0=(2π/l)2×T(Y/12ρ)1/2
...(5)
l is the wavelength. Similarly, positionally and temporally π
By changing the phase of /2, ξ2=ξ0cos(n
X)×cos(ω0t)
...(6) When these two vibrations are added together, a traveling wave of bending vibration is obtained. ξ=ξ1+ξ2=ξ0cos(nX−ω0t)
…(7
) The phase velocity v is v=ω0/n=(2π/l)T(Y/12ρ)
1/2...(8) is found. This vibration is with respect to the neutral surface, and on a surface with thickness T (at a position T/2 away from the neutral surface), ζ=ξ0n(T/2)×sin(nX-ω0t
)=πξ0(T/l)×sin(nX−ω0t)
…(9)
A displacement in the lateral direction (length L direction) occurs. Equations (7) and (9) indicate that a mass point on the surface moves in an ellipse with a ratio of vertical to horizontal directions of 1:πT/l. When the longitudinal displacement ξ is maximum (nX=ω0t), the lateral displacement ζ is minimum. The speed U of the lateral displacement ζ also becomes maximum, and the following equation is obtained. U=dζ/dt=-πω0ξ0(T/l)×c
os(nX-ω0t) Umax=-πω0ξ0
T/l
...(10) Since it is a traveling wave, the maximum point of the longitudinal displacement ξ moves at the phase velocity v, but the object that comes into contact with the peak moves in a constant direction at the speed expressed by the above equation.
【０００９】以上の構成において、現像装置動作時には
上記電源装置から超音波搬送部材の電源１６７に所定の
電圧が印加され、これにより、電極１６７が設けられた
圧電部材１６５が超音波振動を起こして波打つ状態にな
り、これと共に波打つ弾性部材１６６の表面が反時計向
きに進行する波打ち状態となり、現像ローラ１６１表面
上で反時計向きにトナーを超音波搬送することが出来る
ようになる。このような状態にある現像ローラ１６１に
向けてアジテータ１６３がトナーホッパー内のトナーを
搬送する。搬送されたトナーは弾性補給ローラ１６７で
負極性に摩擦帯電されて現像ローラ１６１表面上に付着
し、超音波搬送で現像ローラ１６１表面を上方に移動し
、薄層化ブレード１６２によって更に負極性に摩擦帯電
されて現像ローラ１６１上で薄層化される。薄層化され
たトナーは超音波搬送されて感光体ドラム１との対向部
である現像領域に至り、感光体ドラム１上の静電潜像に
付着してトナー像化される。感光体表面に付着しなかっ
たトナーはそのまま超音波搬送されつづけて再び現像装
置内に戻る。以上、本実施例によれば、超音波搬送の原
理を用いてトナーを現像ローラ１６１を廻す事なく搬送
し、これにより、現像ローラ１６１の回転によって擦れ
る部分がなくなり、このような部分に進入したトナーに
ストレスが掛かってトナー固着を起こすことが無くなる
。又、現像ローラ１６１が回転しないので渦電流の発生
によるトルクの増大や熱の発生が抑えられ、現像装置内
のトナーが溶解することがない。In the above configuration, when the developing device is in operation, a predetermined voltage is applied from the power supply device to the power supply 167 of the ultrasonic conveying member, whereby the piezoelectric member 165 provided with the electrode 167 causes ultrasonic vibration. At the same time, the surface of the wavy elastic member 166 becomes wavy, progressing counterclockwise, and the toner can be ultrasonically transported counterclockwise on the surface of the developing roller 161. The agitator 163 conveys the toner in the toner hopper toward the developing roller 161 in this state. The conveyed toner is frictionally charged to negative polarity by the elastic replenishing roller 167 and adheres to the surface of the developing roller 161, moved upward on the surface of the developing roller 161 by ultrasonic conveyance, and further changed to negative polarity by the thinning blade 162. It is triboelectrically charged and formed into a thin layer on the developing roller 161. The thinned toner is transported by ultrasonic waves to a development area that is opposite to the photoreceptor drum 1, and is attached to the electrostatic latent image on the photoreceptor drum 1 to form a toner image. The toner that has not adhered to the surface of the photoreceptor continues to be transported by ultrasonic waves and returns to the developing device. As described above, according to the present embodiment, the principle of ultrasonic transport is used to transport the toner without rotating the developing roller 161, thereby eliminating the portions that are rubbed by the rotation of the developing roller 161 and preventing the toner from entering such portions. This prevents toner from being stuck due to stress on the toner. Further, since the developing roller 161 does not rotate, the increase in torque and the generation of heat due to the generation of eddy currents are suppressed, and the toner in the developing device does not dissolve.
【００１０】ここで、現像領域を通過する間の感光体ド
ラム上の潜像へのトナー付着の進行について説明と、ま
ず、第１対向電極１６１ａを通過した直後では、縦軸に
単位面積当たりの付着トナー量（ｍｇ／ｃｍ２）を取り
且つ横軸に潜像電位を取って現像特性を示した図２（ａ
）（図２（ｂ），（ｃ），（ｄ）においても同様）中の
実線Ｄ１で示すように比較的高電位部の現像が行なわれ
る。これは、第１対向電極１６１ａへの印加現像バイア
スを比較的高めに設定して小さな現像電界が形成される
ようにしているので、潜像の比較的低電位部にはトナー
が供給されないためである。次いで、第２対向電極１６
１ｂを通過した直後では、図２（ｂ）中の一点鎖線Ｔ２
で示すように潜像の中電位部まで現像され且つ比較的高
電位部には更に多量のトナーが付着する。これは、現像
バイアスを第１対向電極よりは低めに設定して比較的大
きな現像電界が形成されるようにした第２対向電極１６
１ｂによる現像分が加えられた為である。同図中の実線
Ｄ２はこの第２対向電極１６１ｂのみを用いて現像した
場合の現像特性を示すものであり、これによれば中電位
部まで現像が行なわれる。更に、第３対向電極１６１ｃ
を通過した直後では、同様にして更に低電位部まで現像
が進み、それ以前の対向電極で現像されている潜像部分
には更に多量のトナーが付着し、最終的に第４対向電極
１６１ｄを通過して現像を終了したときには図２（ｃ）
中の二点鎖線で示すように、低電位部、中電位部、高電
位部の何れも良好に現像された理想的な現像が行なわれ
た状態になる。同図中の実線Ｔ４は第４対向電極１６１
ｄのみを用いて現像した場合の現像特性を示すものであ
る。以上のように、本実施例によれば、第１乃至第４対
向電極に互いに異なる異なる現像バイアスを印加して互
いに異なる現像電界を形成するようにし、これにより、
低電位部、中電位部、高電位部夫々の再現性に有利な互
いに異なる現像を重ねて行なうので、理想的な現像特性
を得ることができる。しかも、この例によれば、第１乃
至第４対向電極に順次小さな現像バイアスを印加して順
次大きな現像電界を形成するようにし、これにより、現
像領域を通過する間に比較的上流側の対向電極で一部の
トナーを潜像担持体側に供給してトナー存在率が低下し
た状態で現像を行なう、比較的下流側の対向電極ほど大
きな現像電界を形成するようにしているので、比較的下
流側の対向電極でも充分な量のトナーを潜像へ供給する
ことが出来、現像装置のトナー供給率が高くなる。従っ
て、コピースピードを高速にするために感光体ドラム１
の周速を速くする場合にも容易に対応することが出来る
。[0010] Here, we will explain the progress of toner adhesion to the latent image on the photoreceptor drum while passing through the development area, and firstly, immediately after passing the first counter electrode 161a, the vertical axis shows Figure 2 (a) shows the development characteristics by taking the amount of adhered toner (mg/cm2) and the latent image potential on the horizontal axis.
) (the same applies to FIGS. 2(b), 2(c), and 2(d)), as shown by the solid line D1, the relatively high potential portion is developed. This is because the developing bias applied to the first counter electrode 161a is set relatively high to form a small developing electric field, so toner is not supplied to the relatively low potential areas of the latent image. be. Next, the second counter electrode 16
Immediately after passing through 1b, the dashed line T2 in Fig. 2(b)
As shown in , the latent image is developed up to the middle potential portion, and a larger amount of toner adheres to the relatively high potential portion. This is because the second counter electrode 16 has a developing bias set lower than that of the first counter electrode so that a relatively large developing electric field is formed.
This is because the amount of development by 1b was added. A solid line D2 in the figure shows the development characteristics when development is performed using only this second opposing electrode 161b, and according to this, development is performed up to the middle potential portion. Furthermore, the third counter electrode 161c
Immediately after passing through the fourth counter electrode 161d, development progresses further to the lower potential area in the same way, and a larger amount of toner adheres to the latent image area that was previously developed with the counter electrode, and finally the fourth counter electrode 161d. When the image passes through and the development is completed, it is shown in Fig. 2(c).
As shown by the two-dot chain line in the middle, ideal development is achieved in which all of the low potential area, medium potential area, and high potential area are well developed. The solid line T4 in the figure indicates the fourth counter electrode 161
This figure shows the development characteristics when developing using only d. As described above, according to this embodiment, different developing biases are applied to the first to fourth opposing electrodes to form different developing electric fields, and thereby,
Since different developments are carried out one after another, which are advantageous for the reproducibility of each of the low-potential area, medium-potential area, and high-potential area, ideal development characteristics can be obtained. Moreover, according to this example, a smaller developing bias is applied to the first to fourth opposing electrodes to form a sequentially larger developing electric field, and thereby, while passing through the developing area, the opposing electrodes on the relatively upstream side The electrode supplies some of the toner to the latent image carrier side and develops with the toner presence rate reduced.The counter electrode located relatively downstream forms a larger developing electric field. A sufficient amount of toner can be supplied to the latent image even with the opposing electrode on the side, increasing the toner supply rate of the developing device. Therefore, in order to increase the copy speed, the photosensitive drum 1
This can easily be applied to cases where the circumferential speed of the cylinder is increased.
【００１１】次に、使用対向電極制御について説明する
。周知のように、操作者の選択により、又は、感光体特
性の経時変化を例えば基準潜像を現像して得た基準トナ
ー像の光学濃度等を光学センサ等で自動的に検出して予
め設定されている該検出の結果と現像装置の現像バイア
ス値等の現像条件との関係に従って自動的に、現像装置
の現像バイアス、二成分現像方式のものにおいては設定
トナー濃度等の現像条件を変化させることにより、所望
の画像を得るようにすることが出来る。又、デジタル式
の複写機等においては、画像データから画像の黒部面積
を演算して現像器で使用するトナー量を求め、これに応
じてトナーを補給等することも知られている。更に、環
境によるトナー供給率の変化に対応する為に現像条件を
変化させることも考えられる。例えば、湿度が変化する
とトナー帯電量が変化して潜像に対するトナー付着量が
変化し（高湿度になるほどトナー帯電量が低下して潜像
に対するトナー付着量が増加する）、これにより、トナ
ー供給過多やトナー供給不足になって画質が劣化するこ
とがあるので、このような環境変化を自動的に検出して
現像条件を変化させることも、所望の画像を得るために
は、有効である。Next, control of the counter electrode used will be explained. As is well known, preset settings can be made by the operator's selection or by automatically detecting the optical density of a reference toner image obtained by developing a reference latent image using an optical sensor or the like to detect changes over time in photoreceptor characteristics. Automatically changes development conditions such as the development bias of the development device and the set toner density in the case of a two-component development method, according to the relationship between the detection result and the development conditions such as the development bias value of the development device. By doing so, it is possible to obtain a desired image. Furthermore, in digital copying machines and the like, it is also known to calculate the black area of an image from image data to determine the amount of toner to be used in a developing device, and replenish the toner accordingly. Furthermore, it is also conceivable to change the developing conditions in order to respond to changes in the toner supply rate due to the environment. For example, when the humidity changes, the toner charge amount changes and the toner adhesion amount to the latent image changes (the higher the humidity, the toner charge amount decreases and the toner adhesion amount to the latent image increases), and this causes the toner supply. Since image quality may deteriorate due to excess toner or insufficient toner supply, it is also effective to automatically detect such environmental changes and change the developing conditions in order to obtain a desired image.
【００１２】そこで、本実施例においては、現像領域の
有効現像電極幅を変化させて現像能力を変化させること
が出来るように構成している。即ち、上記のように第２
乃至第４対向電極１６１ｂ，１６１ｃ，１６１ｄについ
ては現像動作中にも電圧印加を行なわないように出来る
ように電源２０ｂ，２０ｃ，２０ｄとの間にスイッチ手
段２１ｂ，２１ｃ，２１ｄを設け、該スイッチ手段を図
示しない制御部でＯＮ／ＯＦＦ制御するように構成して
いる。この制御部は、操作者のキー入力信号により、各
スイッチ手段を制御するものであっても良いし、上記の
ような基準トナー像や環境を自動的に検出した結果に基
づいて各スイッチ手段を制御するものであっても良い。
そして、各スイッチ手段のＯＮ／ＯＦＦは、現像能力を
高める必要があるとき、例えば、操作者が全体的に濃度
が濃いコピーを得たいと希望したとき、基準トナー像の
検出濃度が薄い場合、画像データから求めた黒部面積が
大きいとき、湿度等の環境が現像装置の現像能力を低下
させるものであるとき（例えば、低湿度であるとき）に
は、比較的多数の対向電極を現像バイアス印加状態にす
るように各スイッチ手段を制御し、これにより、有効対
向電極幅を増大させて現像能力を高める。逆に現像能力
を低下させる必要が在るときには、この例においては、
比較的少数の対向電極のみ現像バイアス印加状態にする
ように各スイッチ手段を制御する。Therefore, in this embodiment, the developing capacity can be changed by changing the effective developing electrode width of the developing area. That is, the second
To the fourth opposing electrodes 161b, 161c, and 161d, switch means 21b, 21c, and 21d are provided between the power supplies 20b, 20c, and 20d so that no voltage is applied even during the developing operation. It is configured to be ON/OFF controlled by a control section (not shown). This control section may control each switch means based on a key input signal from the operator, or may control each switch means based on the results of automatically detecting the reference toner image and environment as described above. It may be something that is controlled. The ON/OFF of each switch means is determined when it is necessary to increase the developing ability, for example, when the operator desires to obtain a copy with a high overall density, or when the detected density of the reference toner image is low. When the black area calculated from the image data is large, or when the environment such as humidity reduces the developing ability of the developing device (for example, when the humidity is low), a relatively large number of counter electrodes are applied with developing bias. Each switch means is controlled so as to increase the effective width of the opposing electrode, thereby increasing the developing ability. Conversely, when it is necessary to reduce the developing ability, in this example,
Each switch means is controlled so that only a relatively small number of opposing electrodes are placed in a developing bias applied state.
【００１３】そして、本実施例は上述のように感光体表
面移動方向で下流側の対向電極ほど現像電界が大きくな
るように設定し、これにより、潜像の比較的低電位部の
現像を下流側の対向電極に主に依存させているので、現
像能力を低下させるためにいくつかの対向電極について
のスイッチ手段をＯＦＦにして現像バイアスを印加しな
い状態にする（以下、対向電極をＯＦＦにするという）
ときには、より下流側に位置する対向電極からＯＦＦに
する。換言すれば、いくつかの対向電極のみを現像バイ
アス印加状態にするときには、より下流側に位置する対
向電極から現像バイアス印加状態にする。例えば、１つ
の対向電極をＯＦＦにして現像能力を低下させるときは
、最下流の第４対向電極１６１ｄをＯＦＦにし、２つの
対向電極をＯＦＦにして現像能力を低下させるときは第
４及び第３対向電極１６１ｄ，ｃをＯＦＦにする。これ
は、このように現像能力を低下させる必要が在るときは
、環境変化で現像能力が高くなり過ぎたりして、例えば
、図２（ｄ）中の実線Ｔ４に示すようにトナー付着量が
全体的に増加し、特に低濃度のトナー付着過多による地
汚れの発生を防止する必要が在るときであることから、
潜像の比較的低電位部を主に現像している対向電極から
ＯＦＦするためである。逆にこの場合に上流側の対向電
極をＯＦＦしても、潜像の比較的低電位部は下流側の対
向電極で主に現像されているのであるから、何ら地汚れ
防止に寄与することが出来ない。ここで、第１対向電極
１６１ａのみは現像中に常時現像バイアス印加状態にす
るのは、少なくとも１つの対向電極が現像バイアス印加
状態になければ現像を行なえないからである。In this embodiment, as described above, the developing electric field is set to be larger as the opposing electrode is located downstream in the direction of movement of the surface of the photoreceptor. Since the developing ability is mainly dependent on the opposite electrode on the side, in order to reduce the developing ability, the switch means for some of the opposite electrodes are turned OFF and no developing bias is applied (hereinafter, the opposite electrode is turned OFF). )
Sometimes, the counter electrode located further downstream is turned off. In other words, when only some of the counter electrodes are placed in the developing bias application state, the developing bias is applied from the counter electrodes located on the downstream side. For example, when one opposing electrode is turned OFF to reduce the developing ability, the fourth opposing electrode 161d at the most downstream side is turned OFF, and when two opposing electrodes are turned OFF to reduce the developing ability, the fourth and third opposing electrodes are turned OFF. Turn off the counter electrodes 161d and 161c. This is because when it is necessary to reduce the developing ability in this way, the developing ability may become too high due to environmental changes, and for example, the amount of toner adhesion may decrease as shown by the solid line T4 in FIG. 2(d). This is a time when it is necessary to prevent background smudges caused by excessive adhesion of low-concentration toner.
This is to turn off the counter electrode which is mainly developing the relatively low potential portion of the latent image. Conversely, in this case, even if the upstream counter electrode is turned off, the relatively low potential portion of the latent image is mainly developed by the downstream counter electrode, so it does not contribute to preventing background smearing in any way. Can not. Here, the reason why only the first counter electrode 161a is always kept in a developing bias applied state during development is that development cannot be performed unless at least one counter electrode is in a developing bias applied state.
【００１４】尚、上記実施例においては、現像ローラ１
６１の表面曲率が感光体ドラム１の表面曲率と異なるも
のであるが、これに代え、図３に示すように両曲率が同
じになるように現像ローラ１６１の感光体ドラム表面対
向領域の形状を設定し、各対向電極と感光体ドラム表面
の距離が同一になるようにしても良い。又、図３の例で
は第１乃至第４対向電極に同一の現像バイアス値を電圧
を印加している。これにおいても、下流側の２つの対向
電極１６１ｃ，１６１ｄをＯＮ／ＯＦＦ可能なようにス
イッチ手段を介して電源に接続しているので、上記実施
例と同様の使用対向電極制御によって現像能力を変化さ
せることが出来る。更に、以上の各実施例においては、
一成分現像装置を例に取って説明したが、二成分現像装
置についても適用することが出来る。In the above embodiment, the developing roller 1
The surface curvature of the developing roller 161 is different from the surface curvature of the photoreceptor drum 1, but instead, the shape of the area of the developing roller 161 facing the photoreceptor drum surface is changed so that both curvatures are the same, as shown in FIG. The distance between each counter electrode and the surface of the photoreceptor drum may be set to be the same. Further, in the example shown in FIG. 3, the same developing bias value is applied to the first to fourth opposing electrodes. In this case as well, since the two downstream opposing electrodes 161c and 161d are connected to the power source via a switch so that they can be turned on and off, the developing ability can be changed by controlling the opposing electrodes used in the same manner as in the above embodiment. I can do it. Furthermore, in each of the above embodiments,
Although the description has been made using a one-component developing device as an example, the present invention can also be applied to a two-component developing device.
【００１５】[0015]
【発明の効果】以上のように請求項１の発明によれば、
現像剤担持部材を回転させることなく現像剤を現像領域
へ搬送して該現像剤を潜像に応じて付着させて現像を行
なうので、現像スリーブが回転する従来のもののように
現像スリーブとこれを支持する現像装置側板間にトナー
が進入してトナーが擦れてトナー固着等が起こり、画像
に悪影響を及ぼすような等不具合を防止することが出来
る。請求項２の発明によれば、２以上の互いに異なる現
像電界が形成される対向電極で２種以上の異なる現像特
性による現像を行なうので、単一の現像剤搬送手段で所
謂γ補正を行なうことが出来、これにより、簡易な構成
で良好な現像特性を得ることが出来る。請求項３乃至５
の発明によれば、上記電源装置により上記潜像担持体表
面の移動方向下流側に設けられた上記対向電極ほど強度
の大きな現像電界を形成し、比較的下流側の対向電極に
おいても、潜像担持体側への充分なトナー供給を行ない
得るようにするので、潜像担持体に対するトナー供給効
率を向上させることが出来、これにより、トナー飛散や
騒音を発生することも無く画像形成動作の高速化に対応
することが出来る。請求項６乃至９の発明によれば、複
数の対向電極のうちの少なくとも１以上に電圧遮断状態
にし得るスイッチ手段を設け、制御手段で該スイッチを
制御して対向電極効果を発揮しえる対向電極の個数を変
え、有効な現像領域幅を変えてトナー供給率を変化させ
るので、操作者の選択により、又は、画像や現像能力に
影響する環境変動を検出して所望の現像能力になるよう
に制御することが出来る。[Effect of the invention] As described above, according to the invention of claim 1,
Since the developer is conveyed to the developing area and attached to the latent image without rotating the developer carrying member, development is carried out by attaching the developer to the latent image. It is possible to prevent problems such as toner sticking between the side plates of the supporting developing device due to the toner rubbing and toner sticking, which would adversely affect the image. According to the invention of claim 2, since development is performed using two or more different development characteristics with the opposing electrodes where two or more different development electric fields are formed, so-called γ correction can be performed with a single developer conveying means. As a result, good development characteristics can be obtained with a simple configuration. Claims 3 to 5
According to the invention, the power supply device forms a developing electric field that is stronger as the counter electrode is provided downstream in the direction of movement of the surface of the latent image carrier, and even in the counter electrode located relatively downstream, the latent image is Since sufficient toner is supplied to the carrier side, the efficiency of toner supply to the latent image carrier can be improved, thereby increasing the speed of image forming operations without toner scattering or noise. It is possible to respond to According to the invention of claims 6 to 9, at least one of the plurality of counter electrodes is provided with a switch means capable of setting a voltage cutoff state, and the control means controls the switch to provide the counter electrode effect. Since the toner supply rate is changed by changing the number of toners and changing the effective development area width, the desired development performance can be achieved by the operator's selection or by detecting environmental changes that affect the image or development performance. It can be controlled.
【図１】（ａ）は本発明の一実施例に係る現像装置の概
略構成図、（ｂ）は同現像装置の現像ローラの対向電極
配置の説明図。FIG. 1(a) is a schematic configuration diagram of a developing device according to an embodiment of the present invention, and FIG. 1(b) is an explanatory diagram of the arrangement of opposing electrodes of a developing roller of the developing device.
【図２】同現像装置の現像特性を説明するための特性図
であり、（ａ）は第１対向電極通過後、（ｂ）は第２対
向電極通過後、（ｃ）は第４対向電極通過後、（ｄ）は
比較低湿度における現像で第４対向電極通過後の現像特
性を示す特性図。FIG. 2 is a characteristic diagram for explaining the development characteristics of the developing device, in which (a) is after passing through the first counter electrode, (b) is after passing through the second counter electrode, and (c) is after passing through the fourth counter electrode. After passing, (d) is a characteristic diagram showing the development characteristics after passing through the fourth counter electrode in development at relatively low humidity.
【図３】変形例にかかる現像ローラの概略図。FIG. 3 is a schematic diagram of a developing roller according to a modified example.
１ 感光体ドラム
， １６ 現像装置
２０ａ，ｂ，ｃ，ｄ 電源
２１ｂ，ｃ，ｄ スイッチ手段１６０
ローラ軸
， １６１ 現像ローラ
１６１ａ，ｂ，ｃ，ｄ 対向電極
１６２ 薄層化ブレード
， １６３ アジテータ
１６４ 電極
， １６５ 圧電部材
１６６ 弾性部材
， １６７ 回転弾性ローラ1 Photoreceptor drum
, 16 developing devices 20a, b, c, d power supplies 21b, c, d switching means 160
roller shaft
, 161 Developing rollers 161a, b, c, d Counter electrode 162 Thinning blade
, 163 agitator 164 electrode
, 165 piezoelectric member 166 elastic member
, 167 Rotating elastic roller
Claims (9)
する現像領域に装置内の現像剤を搬送する現像剤搬送手
段を超音波搬送部材を用いて構成し、該現像剤搬送手段
の該現像領域に在る部分に導電性の対向電極を設けたこ
とを特徴とする現像装置。1. A developer transporting means for transporting the developer inside the apparatus to a developing area exposed from inside the apparatus and facing the surface of the latent image carrier, comprising an ultrasonic transporting member, the developer transporting means A developing device characterized in that a conductive counter electrode is provided in a portion of the developing area.
の移動方向にならべて上記対向電極を互いに絶縁状態で
複数設け、該複数の対向電極に電圧を印加する電源装置
を、該複数の対向電極のうち少なくとも２以上が互いに
異なる強度の現像電界を形成するように構成したことを
特徴とする請求項１の現像装置。2. A plurality of the opposing electrodes are provided insulated from each other in the direction of movement of the surface of the latent image carrier in the development area, and a power supply device for applying a voltage to the plurality of opposing electrodes is arranged in a direction in which the surface of the latent image carrier is moved. 2. The developing device according to claim 1, wherein at least two of the electrodes are configured to form developing electric fields of mutually different intensities.
動方向下流側に設けられた上記対向電極ほど強度の大き
な現像電界を形成するように構成したことを特徴とする
請求項２の現像装置。3. The power supply device according to claim 2, wherein the power supply device is configured to form a developing electric field with a stronger intensity as the opposing electrode is provided downstream in the direction of movement of the surface of the latent image carrier. Developing device.
性に帯電した現像剤を用いて現像を行なう請求項２の現
像装置において、上記電源装置を、上記潜像担持体表面
の移動方向下流側に設けられた上記対向電極ほど、上記
対向電極と上記潜像担持体表面との距離に対する印加電
圧の絶対値の比が小さくなる電圧を印加するように構成
したことを特徴とする請求項２の現像装置。4. The developing device according to claim 2, wherein the development is carried out using a developer charged with a polarity different from the uniformly charged polarity of the surface of the latent image carrier. The counter electrode is configured to apply a voltage such that the ratio of the absolute value of the applied voltage to the distance between the counter electrode and the surface of the latent image carrier becomes smaller as the counter electrode is provided downstream in the moving direction. A developing device according to claim 2.
性に帯電した現像剤を用いて現像を行なう請求項２の現
像装置において、上記複数の対向電極を、上記潜像担持
体表面との距離が互いに等しくなるよう設け、上記電源
装置を、上記潜像担持体表面の移動方向下流側に設けら
れた上記対向電極ほど、上記対向電極と上記潜像担持体
表面との距離に対する印加電圧の絶対値の比が大きくな
る電圧を印加するように構成したことを特徴とする請求
項２の現像装置。5. The developing device according to claim 2, wherein the developing device performs development using a developer charged to the same polarity as the uniformly charged polarity of the surface of the latent image carrier, wherein the plurality of opposing electrodes are connected to the surface of the latent image carrier. The power supply device is arranged such that the distance between the counter electrode and the surface of the latent image carrier is equal to the distance between the counter electrode and the surface of the latent image carrier. 3. The developing device according to claim 2, wherein the developing device is configured to apply a voltage that increases the ratio of the absolute values of the applied voltages.
の移動方向にならべて上記対向電極を互いに絶縁状態で
複数設け、該対向電極のうちの少なくとも１以上に、他
の対向電極への電圧印加状態のときに電圧遮断状態にし
得るスイッチ手段を設け、該スイッチ手段を制御する制
御手段を設けたことを特徴とする請求項１の現像装置。6. A plurality of the opposing electrodes are provided insulated from each other in the direction of movement of the surface of the latent image carrier in the developing area, and at least one of the opposing electrodes is connected to a voltage applied to another opposing electrode. 2. The developing device according to claim 1, further comprising a switch means capable of turning off the voltage when the voltage is applied, and a control means for controlling the switch means.
装置を、上記潜像担持体表面の移動方向下流側に設けら
れた上記対向電極ほど強度の大きな現像電界を形成する
ように構成し、上記スイッチ手段は上記静電潜像表面の
移動方向下流側の上記対向電極から設け、上記制御手段
を、上記スイッチ手段のうち１以上について電圧を遮断
する場合に、上記静電潜像表面の移動方向下流側の上記
対向電極についての上記スイッチ手段から遮断するよう
に構成したことを特徴とする請求項６の現像装置。7. A power supply device for applying a voltage to the plurality of counter electrodes is configured to form a developing electric field with a stronger intensity as the counter electrodes are provided downstream in the direction of movement of the surface of the latent image carrier. , the switch means is provided from the counter electrode downstream in the moving direction of the electrostatic latent image surface, and when the control means cuts off the voltage for one or more of the switch means, 7. The developing device according to claim 6, wherein the opposing electrode on the downstream side in the moving direction is cut off from the switching means.
のうち少なくとも１つには設けないことを特徴とする請
求項６又は７の現像装置。8. The developing device according to claim 6, wherein said switch means is not provided on at least one of said plurality of opposing electrodes.
動を検出する検出手段を設け、上記制御手段を、該検出
手段の出力に基づいて上記スイッチ手段を制御するよう
に構成したことを特徴とする請求項６又は７の現像装置
。9. A detection means for detecting environmental changes that affect the image or the developing ability of the apparatus is provided, and the control means is configured to control the switch means based on the output of the detection means. 8. The developing device according to claim 6 or 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3151119A JPH04347878A (en) | 1991-05-26 | 1991-05-26 | Developing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3151119A JPH04347878A (en) | 1991-05-26 | 1991-05-26 | Developing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04347878A true JPH04347878A (en) | 1992-12-03 |
Family
ID=15511784
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3151119A Withdrawn JPH04347878A (en) | 1991-05-26 | 1991-05-26 | Developing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04347878A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809385A (en) * | 1997-06-30 | 1998-09-15 | Xerox Corporation | Reproduction machine including and acoustic scavengeless assist development apparatus |
-
1991
- 1991-05-26 JP JP3151119A patent/JPH04347878A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809385A (en) * | 1997-06-30 | 1998-09-15 | Xerox Corporation | Reproduction machine including and acoustic scavengeless assist development apparatus |
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