JPS60194476A

JPS60194476A - Method for stopping feed of developer in electrophotographic copying machine

Info

Publication number: JPS60194476A
Application number: JP59048060A
Authority: JP
Inventors: Isao Katsuta; 勝田　勇生; Kaneyoshi Miura; 三浦　兼能
Original assignee: Fuji Xerox Co Ltd
Current assignee: Fujifilm Business Innovation Corp
Priority date: 1984-03-15
Filing date: 1984-03-15
Publication date: 1985-10-02
Also published as: JPH0222384B2

Abstract

PURPOSE:To prevent the surface of a photosensitive body from being contacted with developer after the end of development by reversing a developing roll after stopping a developing machine, and after opposing the developer unadhering part of the developing roll to the photosensitive body, stopping the developing roll. CONSTITUTION:When development starts, the developer 6 mixed by a blender 5 is carried to the developing roll 3 by a transport roll 4 and magnetized on the periphery of the roll 3 to form a magnetic brush and the magnetic brush is slided on the surface of the photosensitive body 2 to develop an electrostatic image on the photosensitive body 2. After the development of the electrostatic image, the residual developer 6 at the part B of the developing roll 3 provided with internal magnets adjoining the same magnetic poles each other is dropped by the magnetic force. Therefore, no developer is adhered to the part between a part A starting to magnetize the developer 6 and the part B dropping the developer. After the end of the development, the developing roll 3 is reversed until the developer unadhered part is opposed to the photosensitive body 2 and then the developing roll 3 is stopped.

Description

【発明の詳細な説明】産業上の利用分野本発明は電子複写機の現像機に関するものである。[Detailed description of the invention] Industrial applications The present invention relates to a developing machine for an electronic copying machine.

従来技術電子複写機において現像機は感光体に近接して配設され
ており、複写終了時には、現像ロールはその周面に未使
用の現像剤が感光体に接触した状態で停止しているが、
長時間このような状態が続くと、複写中に発生したオゾ
ン等によって現像剤が化学反応を起こし、感光体表面に
付着してしまうことがある。このような状態で次の複写
を行なうと、得ら・れた複写物上に像抜けが生じたり像
かにじんだりして良質の複写物が得られない。このため
複写が終了した後に現像ロールを感光体から離して感光
体に現像剤が接触しないようにする方法が提案されてい
る。In conventional electronic copying machines, the developing machine is disposed close to the photoreceptor, and at the end of copying, the developing roll is stopped with unused developer on its circumferential surface in contact with the photoreceptor. ,
If this condition continues for a long time, the developer may cause a chemical reaction due to ozone or the like generated during copying, and may adhere to the surface of the photoreceptor. If the next copy is made in such a state, the resulting copy will have missing images or blurred images, making it impossible to obtain a good quality copy. For this reason, a method has been proposed in which the developing roll is separated from the photoreceptor after copying is completed to prevent the developer from coming into contact with the photoreceptor.

またカラー複写機のように現像機が複数備えられている
ものでは、１色ごとに現像を行ない、使用されていない
現像機は常に感光体から離れていなければならない。な
ぜならある色の静電像を現像するときに、それζこ関与
しない他の現像ロールに付着している現像剤によってこ
の静電像が破壊される恐れがあるからである。Furthermore, in a color copying machine equipped with a plurality of developing machines, development is performed for each color, and developing machines that are not in use must always be kept away from the photoreceptor. This is because when an electrostatic image of a certain color is developed, there is a risk that this electrostatic image may be destroyed by the developer adhering to other developing rolls that are not involved in the development.

従来はソレノイドやスプリングの作用で現像機を移動さ
せ、現像時には現像ロールが感光体と一定の距離を保っ
て近接するように、また現像後には現像ロールが感光体
から離れるようにしていた。しかしこのように構成した
装置は機構が複雑であるため製造コストが高くなり、ま
た現像ロールと感光体の距離を一定に保つようにソレノ
イドやスプリングを調節することは困難であり、この距
離が変わり易く、現像剤が均一に感光体に付着せず、得
られた複写物に濃度ムラが発生するという問題があった
。Conventionally, a developing machine was moved using a solenoid or a spring so that the developing roll came close to the photoreceptor at a certain distance during development, and moved away from the photoreceptor after development. However, devices configured in this way have a complicated mechanism, which increases manufacturing costs.Also, it is difficult to adjust the solenoid and spring to maintain a constant distance between the developing roll and the photoreceptor, and this distance does not change. However, there is a problem in that the developer does not adhere uniformly to the photoreceptor, resulting in density unevenness in the obtained copies.

このような装置とは別に、現像終了後に現像機内のトラ
ンスポートロールまたは現像ロールにスクレーバーを圧
接し、それらの表面の現像剤を掻き落とすものも提案さ
れているが、スクレーパーをロールに均一に密接させる
ためには高精度が要求され、現像剤を完全に掻き落とす
ことは困難であった。Apart from such a device, there has also been proposed a device in which a scraper is pressed into contact with the transport roll or developing roll in the developing machine after development is completed to scrape off the developer on the surface of the transport roll or developing roll in the developing machine. This requires high precision, and it is difficult to completely scrape off the developer.

発明の目的本発明の目的は上記従来の問題点を解消して、現像が終
了した後に感光体表面に現像剤が接触することのない現
像剤の供給停止方法を提供することにある。OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a method for stopping the supply of developer in which the developer does not come into contact with the surface of a photoreceptor after development is completed.

発明の構成本発明は、感光体に近接して回転しながら感光体に現像
剤を供給する現像ロールと、この現像ロールに近接して
回転しながら現像ロールに現像剤を搬送するトランスポ
ートロールとを備えた電子複写機の現像機において、現
像機を停止させた後に現像ロールを逆転させ、現像ロー
ルの現像剤無付着部が感光体に対向した後に現像ロール
を停止させて感光体への現像剤供給を停止する方法であ
る。Structure of the Invention The present invention comprises a developing roll that rotates close to the photoreceptor and supplies developer to the photoreceptor, and a transport roll that rotates close to the developer roll and transports the developer to the developer roll. In the developing machine of an electronic copying machine equipped with the above, after the developing machine is stopped, the developing roll is reversed, and after the developer-free part of the developing roll faces the photoreceptor, the developing roll is stopped and the development on the photoreceptor is performed. This is a method of stopping the agent supply.

現像ロールの現像を終えた部分は現像ロール内の磁石の
反発作用で現像剤がすべて落下するようになっており、
次の現像ではまた新たにトランスポートロールから搬送
されてきた現像剤が磁着する。したがってずでに現像剤
が落下した部分が感光体に対向するように現像ロールを
逆転すれば、感光体表面には現像剤は接触しないので現
像剤の付着は確実に防止できる。The part of the developing roll that has finished development is designed so that all the developer falls off due to the repulsion of the magnet inside the developing roll.
In the next development, the developer newly conveyed from the transport roll is magnetically attached. Therefore, if the developing roll is reversed so that the part where the developer has fallen faces the photoreceptor, the developer will not come into contact with the surface of the photoreceptor, so that adhesion of the developer can be reliably prevented.

実施例添付図面を参照しながら、本発明を実施例に則して説明
する。Embodiments The present invention will be explained based on embodiments with reference to the accompanying drawings.

第１図は現像機の概略図であり、現像機１はその内部に
現像ロール３、トランスポートロール４およびブレンダ
ー５が回転可能に設けられ、感光体２の下部に現像ロー
ル３が近接するように配設されている。ここで矢印は現
像中の回転方向を表わす。現像が始まるとブレンダー５
によってよく攪拌された現像剤６は、トランスポートロ
ール４によって現像ロール３まで搬送され、現像ロール
３の局面に磁着して磁気ブラシを形成する。この磁気ブ
ラシは現像ロール３の回転によって感光体２の表面を摺
擦して感光体２上の静電像を現像し顕像化する。感光体
２上の静電像の現像が終了すると、内部磁石が同極どう
し隣接して備えられている現像ロール３のＢ部において
、残留した現像剤６は磁石の反発力により強制的に落下
させられる。したがって現像ロール３の下部の、現像剤
６が磁着し始めるＡ部と現像剤６が落下するＢ部との間
は、現像剤６がまったく付着していない状態となる。FIG. 1 is a schematic diagram of a developing machine, in which a developing roll 3, a transport roll 4, and a blender 5 are rotatably provided, and the developing roll 3 is placed close to the bottom of the photoreceptor 2. It is located in Here, the arrow represents the direction of rotation during development. When development starts, blender 5
The developer 6 well stirred by the developer 6 is conveyed to the developing roll 3 by the transport roll 4, and is magnetically attached to the surface of the developing roll 3 to form a magnetic brush. This magnetic brush rubs the surface of the photoreceptor 2 as the developing roll 3 rotates to develop and visualize the electrostatic image on the photoreceptor 2. When the development of the electrostatic image on the photoreceptor 2 is completed, the remaining developer 6 is forcibly dropped by the repulsive force of the magnets in the B part of the developing roll 3, where internal magnets with the same polarity are adjacent to each other. I am made to do so. Therefore, at the lower part of the developing roll 3, between the part A where the developer 6 begins to be magnetically attached and the part B where the developer 6 falls, no developer 6 is attached at all.

ここで第２図に示すように、現像が終了した後に現像ロ
ール３を矢印で示す如く逆転させて、現像剤無付着部分
が感光体２に対向する位置まで回転した後現像ロール３
の回転を停止させる。Here, as shown in FIG. 2, after the development is completed, the developing roll 3 is reversed as shown by the arrow, and after the developing roll 3 has rotated to a position where the developer-free portion faces the photoreceptor 2, the developing roll 3
stop the rotation.

従って、感光体２は現像ロール３上の現像剤６と接触し
ない状態で停止し、ていることができ、現像剤６の影響
を受けることはない。Therefore, the photoreceptor 2 can be stopped without contacting the developer 6 on the developing roll 3, and is not affected by the developer 6.

発明の効果本発明によれば、現像機は現像終了後、現像ロールが逆
転して現像剤無付着部分が感光体に対向して停止するの
で、現像時以外、すなわち転写中あるいは停止中には感
光体表面に現像剤はまったく接触しない。したがって感
光体表面に現像剤が付着して次の複写に悪影響を及ぼす
ことがなくなる。また、本発明は現像機を感光体から離
隔させる手段を用いずに、現像ロールを逆転させるだけ
なので、複雑な機構を必要としない等の特長がある。Effects of the Invention According to the present invention, in the developing machine, after the development is completed, the developing roll is reversed and stops with the developer-free area facing the photoreceptor, so that there is The developer never comes into contact with the surface of the photoreceptor. This prevents developer from adhering to the surface of the photoreceptor and adversely affecting subsequent copying. Further, the present invention has the advantage that it does not require a complicated mechanism because the developing roll is simply reversed without using any means for separating the developing device from the photoreceptor.

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

第１図は現像中の現像機の概略断面図、第２図は停止中
の現像機の断面図である。図中符号：１・・・現像機；２・・・感光体；３・・・現像ロール
；４・・・トランスポートロール；５・・・ブレンダー
；６・・・現像剤。 −７＋−FIG. 1 is a schematic sectional view of the developing machine during development, and FIG. 2 is a sectional view of the developing machine while it is stopped. Symbols in the figure: 1... Developing machine; 2... Photoreceptor; 3... Developing roll; 4... Transport roll; 5... Blender; 6... Developer. -7+-

Claims

【特許請求の範囲】[Claims]

感光体に近接して回転しながら感光体に現像剤を供給す
る現像ロールと、この現像ロールに近接して回転しなが
ら現像剤を搬送するトランスボートロールとを備えた電
子複写機の現像機において、現像機を停止させた後に現
像ロールを逆転させて現像ロールの現像剤無付着部が感
光体に対向した後に現像ロールを停止させることを特徴
とする感光体への現像剤供給停止方法。In a developing machine of an electronic copying machine, which is equipped with a developing roll that rotates close to a photoconductor and supplies developer to the photoconductor, and a transport roll that rotates close to the developer roll and conveys the developer. A method for stopping the supply of developer to a photoconductor, which comprises stopping the developing machine, then reversing the development roll so that the developer-free portion of the development roll faces the photoconductor, and then stopping the development roll.