Nothing Special   »   [go: up one dir, main page]

JPH10171252A - Image forming device - Google Patents

Image forming device

Info

Publication number
JPH10171252A
JPH10171252A JP34243396A JP34243396A JPH10171252A JP H10171252 A JPH10171252 A JP H10171252A JP 34243396 A JP34243396 A JP 34243396A JP 34243396 A JP34243396 A JP 34243396A JP H10171252 A JPH10171252 A JP H10171252A
Authority
JP
Japan
Prior art keywords
developing
developer
developing chamber
carrier
magnetic
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.)
Pending
Application number
JP34243396A
Other languages
Japanese (ja)
Inventor
Tsuneji Masuda
恒司 桝田
Yuji Sakami
裕二 酒見
Takao Ogata
隆雄 尾形
Kazuhiro Hasegawa
和弘 長谷川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP34243396A priority Critical patent/JPH10171252A/en
Publication of JPH10171252A publication Critical patent/JPH10171252A/en
Pending legal-status Critical Current

Links

Landscapes

  • Magnetic Brush Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing a scavenging phenomenon where carriers in a developer scrape an image, while improving developability and preventing the problems of a void, etc., by a multistage developing system. SOLUTION: A developing device 40 is provided with two developing chambers 42A and 43A in the rotational direction of a photoreceptor drum 39. The developing chamber 42A on the upstream side is provided with a developing sleeve 42 incorporating a magnet 42a, a stirring screw, etc., houses a two-component developer and develops an electrostatic latent image formed on the drum 39 by a two-component magnetic brush developing system. The developing chamber 43A on the downstream side adopts a nonmagnetic one- component developing system, for preventing the scavenging phenomenon. Further, the developing chamber 43A is provided with a developing sleeve 43, an elastic roller as a toner supplying member, etc., houses nonmagnetic toner of a one-component developer and superimposes/develops the same latent image on the drum 39 by the nonmagnetic one-component developing system.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は、複写装置、画像記
録装置、プリンター、ファクシミリ等の電子写真を用い
た画像形成装置に関し、特に同一の静電潜像を2回の現
像工程で可視化する多段現像方式を採用した画像形成装
置に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, an image recording apparatus, a printer, a facsimile, etc. The present invention relates to an image forming apparatus employing a developing method.

【0002】[0002]

【従来の技術】従来より、磁性キャリアと非磁性トナー
からなる2成分現像剤を内部に磁石を固定配設した現像
スリーブ上に磁気的に担持させ、現像スリーブの回転に
より感光ドラムと現像スリーブとの間の現像領域を通過
させることによって、感光ドラム上の静電潜像を現像し
可視化する、いわゆる2成分磁気ブラシ現像装置が知ら
れている。
2. Description of the Related Art Conventionally, a two-component developer composed of a magnetic carrier and a non-magnetic toner has been magnetically carried on a developing sleeve in which a magnet is fixedly arranged, and the photosensitive drum and the developing sleeve are rotated by rotation of the developing sleeve. A so-called two-component magnetic brush developing device is known in which an electrostatic latent image on a photosensitive drum is developed and visualized by passing through a developing area between the two.

【0003】このような2成分磁気ブラシ現像装置に、
感光ドラムの回転方向にそって上流側と下流側に2本の
現像スリーブを備えさせ、上流側の現像スリーブを用い
た第1の現像工程と、下流側の現像スリーブを用いた第
2の現像工程とにより、感光ドラム上の同一の静電潜像
を重ねて現像して、現像性を向上させたり、画像後端部
の白抜け防止等を図った、多段現像方式を採用した画像
形成装置が提案されている。
In such a two-component magnetic brush developing device,
A first developing step using the upstream developing sleeve, and a second developing using the downstream developing sleeve, in which two developing sleeves are provided on the upstream side and the downstream side along the rotation direction of the photosensitive drum. An image forming apparatus adopting a multi-stage developing method, in which the same electrostatic latent image on the photosensitive drum is overlaid and developed depending on the process, to improve developability, to prevent white spots at the rear end of the image, and the like. Has been proposed.

【0004】[0004]

【発明が解決しようとする課題】しかしながら、かかる
現像方法においては、上流側の現像スリーブによって現
像された感光ドラム上のトナー像のうち、ハーフトーン
部のようなトナーの少ない部分が、下流側の現像スリー
ブによって再び現像される際に、いわゆるキャリアによ
る画像のスキャベジング現象、すなわちキャリアが機械
的或いは静電気的に画像を掻きとって、画像を乱す現象
が生じることがあった。
However, in such a developing method, in the toner image on the photosensitive drum developed by the upstream developing sleeve, a portion having a small amount of toner, such as a halftone portion, is formed on the downstream side. When the image is developed again by the developing sleeve, a so-called scavenging phenomenon of the image by the carrier, that is, a phenomenon that the carrier mechanically or electrostatically scrapes the image and disturbs the image sometimes occurs.

【0005】従って、本発明の目的は、多段現像方式に
より現像性の向上と白抜けなどの問題を防止しつつ、ス
キャベジング現象を防ぐことを可能とした画像形成装置
を提供することである。
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus capable of preventing a scavenging phenomenon while improving a developing property and preventing problems such as white spots by a multi-stage developing method.

【0006】[0006]

【課題を解決するための手段】上記目的は、本発明にか
かる画像形成装置にて達成される。要約すれば、本発明
は、現像装置が像担持体の移動方向にそって、現像剤担
持体を備えた2つの現像室を有し、像担持体に形成した
静電潜像を一方の現像室により現像し、その同一静電潜
像を他方の現像室により更に現像する画像形成装置にお
いて、前記一方の現像室による現像は、非磁性トナーと
磁性キャリアとを混合した2成分現像剤による2成分磁
気ブラシ現像方式であり、他方の現像室による現像は、
非磁性トナーのみからなる1成分現像剤による非磁性1
成分現像方式であることを特徴とする画像形成装置であ
る。
The above object is achieved by an image forming apparatus according to the present invention. In summary, according to the present invention, the developing device has two developing chambers provided with a developer carrier along the moving direction of the image carrier, and the electrostatic latent image formed on the image carrier is developed by one of the developing chambers. In an image forming apparatus in which the same electrostatic latent image is further developed in the other developing chamber, the development in the one developing chamber is performed by a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed. It is a component magnetic brush development method, and the development by the other developing chamber is
Non-magnetic 1 by one-component developer consisting of only non-magnetic toner
An image forming apparatus using a component developing method.

【0007】本発明によれば、前記他方の現像室に非磁
性トナーのみからなる1成分現像剤が収容され、前記他
方の現像室は現像剤供給弾性部材を有し、この弾性部材
が現像剤担持体に当接して移動することにより、前記非
磁性トナーを現像剤担持体に担持させる。或いは、前記
他方の現像室に非磁性トナーと磁性キャリアとを混合し
た2成分現像剤が収容され、前記他方の現像室は磁石を
内蔵した現像剤供給部材を有し、この他方の現像室の現
像剤供給部材が現像剤を担持すると共に、現像剤中の非
磁性トナーを磁気ブラシ方式により前記他方の現像室の
現像剤担持体に担持させる。もしくは、前記他方の現像
室に非磁性トナーと磁性キャリアとを混合した2成分現
像剤が収容され、前記他方の現像室の現像剤担持体は、
前記一方の現像室の現像剤担持体との対向部に少なくと
も反撥磁極を有する磁石を内蔵し、この他方の現像室の
現像剤担持体が現像剤を担持すると共に、前記一方の現
像室の現像剤担持体との対向部において現像剤中のキャ
リアに対する磁気拘束力を弱め、現像剤中の非磁性トナ
ーだけを残留しキャリアを前記一方の現像室の現像剤担
持体に移行させることにより、前記他方の現像室の現像
剤担持体が非磁性トナーを担持する。
According to the present invention, the other developing chamber contains a one-component developer consisting of only non-magnetic toner, and the other developing chamber has a developer supply elastic member, and the elastic member is The non-magnetic toner is carried on the developer carrier by moving while contacting the carrier. Alternatively, a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed is accommodated in the other developing chamber, and the other developing chamber has a developer supply member having a built-in magnet. The developer supply member carries the developer, and the non-magnetic toner in the developer is carried on the developer carrying member of the other developing chamber by a magnetic brush method. Alternatively, a two-component developer in which a nonmagnetic toner and a magnetic carrier are mixed is stored in the other developing chamber, and a developer carrier of the other developing chamber is
A magnet having at least a repelling magnetic pole is built in a portion of the one developing chamber facing the developer carrying member, and the developer carrying body of the other developing chamber carries the developer, and the developing of the one developing chamber is carried out. By weakening the magnetic binding force on the carrier in the developer at the portion facing the developer carrier, leaving only the non-magnetic toner in the developer and transferring the carrier to the developer carrier in the one developing chamber, The developer carrier in the other developing chamber carries the non-magnetic toner.

【0008】好ましくは、前記一方の現像室が像担持体
の移動方向の上流側に設置され、他方の現像室が像担持
体の移動方向の下流側に設置される。また、前記一方の
現像室による現像時、その現像剤担持体にDCバイアス
にACバイアスを重畳した現像バイアスが印加され、前
記他方の現像室の現像時、その現像剤担持体にDCバイ
アスにACバイアスを重畳した現像バイアスが印加され
る。
Preferably, the one developing chamber is provided on the upstream side in the moving direction of the image carrier, and the other developing chamber is provided on the downstream side in the moving direction of the image carrier. Further, at the time of development by the one developing chamber, a developing bias in which an AC bias is superimposed on a DC bias is applied to the developer carrier, and at the time of development of the other developing chamber, an AC bias is applied to the developer carrier by the DC bias. A developing bias on which a bias is superimposed is applied.

【0009】[0009]

【発明の実施の形態】以下、図面を参照して本発明の実
施例を詳細に説明する。
Embodiments of the present invention will be described below in detail with reference to the drawings.

【0010】実施例1 先ず、本発明の実施例を図1及び図2に基づいて説明す
る。図1は、本発明の画像形成装置の一実施例の概略構
成を示す断面図である。本実施例の画像形成装置は、原
稿台固定、光学系移動、回転ドラム型の転写式の電子写
真複写装置である。
Embodiment 1 First, an embodiment of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a sectional view showing a schematic configuration of an embodiment of the image forming apparatus of the present invention. The image forming apparatus of this embodiment is a transfer type electrophotographic copying apparatus of a fixed original platen, moving optical system, and rotating drum type.

【0011】本実施例において、固定の原稿台ガラス2
0上に原稿19を載置し、所要の複写条件を設定した
後、コピースタートキーを押すと、感光ドラム39が矢
印で示す時計方向に所定の周速度で回転駆動される。ま
た、往復動自在に設置した光源21(反射笠22を被せ
てある)と第1ミラー23が、原稿台ガラス20の下面
に沿ってガラス左辺側のホームポジションからガラス右
辺側へ所定の速度Vで移動し(往動)、第2ミラー2
4、第3ミラー25が同方向にV/2の速度で往動する
ことにより、原稿台ガラス20上に載置した原稿19の
下を向いた画像面が左辺側から右辺側に照明走査され、
その照明走査光の原稿面の反射光が結像レンズ29、固
定第4ミラー26、固定第5未ミラー27、固定第6ミ
ラー28を介して感光ドラム39の面に結像露光(スリ
ット露光)される。
In this embodiment, a fixed platen glass 2
When the copy 19 is pressed after the original 19 is placed on the document 0 and the necessary copy conditions are set, the photosensitive drum 39 is driven to rotate at a predetermined peripheral speed in a clockwise direction indicated by an arrow. Further, the light source 21 (which covers the reflection shade 22) and the first mirror 23, which are reciprocally movable, move at a predetermined speed V from the home position on the left side of the glass to the right side of the glass along the lower surface of the platen glass 20. To move (forward) and the second mirror 2
4. When the third mirror 25 moves in the same direction at a speed of V / 2, the image surface of the original 19 placed on the original platen glass 20 facing downward is illuminated and scanned from the left side to the right side. ,
The reflected light of the illumination scanning light from the document surface is imaged on the surface of the photosensitive drum 39 via the imaging lens 29, the fixed fourth mirror 26, the fixed fifth unmirror 27, and the fixed sixth mirror 28 (slit exposure). Is done.

【0012】回転する感光ドラム39は、上記の露光前
に一次帯電器30により正または負の所定電位に一様に
帯電処理されており、この帯電面に対して上記の露光が
なされることにより、感光ドラム39の面に原稿画像に
対応したパターンの静電潜像が順次形成される。感光ド
ラム39に形成された静電潜像は、現像装置40の現像
スリーブ42、43で現像してトナー像として可視化さ
れる。
The rotating photosensitive drum 39 is uniformly charged to a predetermined positive or negative potential by the primary charger 30 before the above-described exposure, and the above-described exposure is performed on this charged surface. Then, an electrostatic latent image having a pattern corresponding to the original image is sequentially formed on the surface of the photosensitive drum 39. The electrostatic latent image formed on the photosensitive drum 39 is developed by the developing sleeves 42 and 43 of the developing device 40 and is visualized as a toner image.

【0013】一方、図示しない給紙手段により記録材シ
ートPが感光ドラム39に向けて送給され、この記録材
シートPは、ガイド33を通って所定のタイミングで感
光ドラム39と転写帯電器34との間の転写部に導入さ
れる。転写部に導入された記録材シートPは、転写帯電
器34から転写コロナを受けることにより感光ドラム3
9に接し、転写部を通過する間に感光ドラム39の面上
のトナー像が記録材シートPの面に順次転写される。
On the other hand, a recording material sheet P is fed toward a photosensitive drum 39 by a paper supply means (not shown), and the recording material sheet P passes through a guide 33 and a photosensitive drum 39 and a transfer charger 34 at a predetermined timing. And is introduced into the transfer section between them. The recording material sheet P introduced into the transfer unit receives the transfer corona from the transfer charger 34, and the photosensitive drum 3
9, the toner image on the surface of the photosensitive drum 39 is sequentially transferred to the surface of the recording material sheet P while passing through the transfer portion.

【0014】このように転写部を通過してトナー像を転
写された記録材シートPは、分離手段、たとえばドラム
端部に配設した図示しない分離ベルトによって感光ドラ
ム39の面から順次分離され、除電針35によって背面
電荷の除電を受けた後、搬送ガイド38、ガイド18に
より定着器60へ導入され、トナー像の定着を受けて画
像形成物、つまりプリント画像として、画像形成装置の
機外へ排出される。
The recording material sheet P on which the toner image has been transferred by passing through the transfer section is sequentially separated from the surface of the photosensitive drum 39 by separation means, for example, a separation belt (not shown) provided at the end of the drum. After the charge on the back surface is removed by the charge removing needle 35, the toner is introduced into the fixing device 60 by the transport guide 38 and the guide 18, and is fixed to the toner image to form an image-formed product, that is, a print image, out of the image forming apparatus. Is discharged.

【0015】転写が終了した感光ドラム39の面は、ク
リーニング器36のクリーニングブレード37によって
転写残りトナー等の汚れが清掃除去され、繰り返して画
像形成に供される。上述のように往動した移動光学部、
すなわち光源21、反射笠22、第1ミラー23、第2
ミラー24、第3ミラー25は、所定の往動終点に到達
すると復動に転じられ、初めのホームポジションへ戻
り、次のコピーサイクルの開始まで待機する(光学系の
バック工程)。
The surface of the photosensitive drum 39 on which the transfer has been completed is cleaned and removed by the cleaning blade 37 of the cleaning device 36, and is repeatedly used for image formation. The moving optical unit that has moved forward as described above,
That is, the light source 21, the reflection shade 22, the first mirror 23, the second
When the mirror 24 and the third mirror 25 reach the predetermined forward movement end point, they are turned backward, return to the initial home position, and wait for the start of the next copy cycle (optical system back process).

【0016】図1の画像形成装置に設置された現像装置
40を図2に基づいて説明する。本実施例において、現
像装置40は、感光ドラム39の回転方向にそって上下
2つに区画された現像室40A、40Bを有し、それぞ
れ現像スリーブ42、43と、現像剤循環及び撹拌のた
めのスペースとが設けられており、上流側の現像室40
Aのスペースには撹拌スクリュー44が、下流側の現像
室40Bのスペースには搬送ローラ45と弾性ローラ4
8とが設置されている。
The developing device 40 installed in the image forming apparatus shown in FIG. 1 will be described with reference to FIG. In this embodiment, the developing device 40 has two upper and lower developing chambers 40A and 40B along the rotation direction of the photosensitive drum 39, and the developing chambers 40A and 40B, respectively, for developing circulation and stirring. And the upstream developing chamber 40 is provided.
A, a stirring screw 44 is provided in the space A, and a transport roller 45 and an elastic roller 4 are provided in the space of the developing chamber 40B on the downstream side.
8 are installed.

【0017】上流側の現像室40Aでは、粒径8μmの
ネガトナーと粒径50μmのフェライトキャリアを混合
した2成分現像剤4を収容して、2成分磁気ブラシ現像
が行なわれ、下流側の現像室40Bでは、粒径8μmの
ネガートナーからなる非磁性1成分現像剤5を収容し
て、非磁性1成分現像が行なわれる。
In the upstream developing chamber 40A, a two-component developer 4 in which a negative toner having a particle diameter of 8 μm and a ferrite carrier having a particle diameter of 50 μm are mixed is accommodated, and two-component magnetic brush development is performed. At 40B, a non-magnetic one-component developer 5 containing a negative toner having a particle diameter of 8 μm is accommodated, and non-magnetic one-component development is performed.

【0018】以下、それぞれの現像工程を説明する。先
ず、上流側の現像室40Aでは、撹拌スクリュー44に
よって現像剤4を撹拌して、内部に磁石42aを固定配
設した現像スリーブ42に供給し、その現像剤4を現像
スリーブ42の表面に担持して感光ドラム39に向けて
搬送し、その搬送途上においてドクターブレード46に
より適正な現像剤量に規制する。感光ドラム39に向け
て搬送された現像剤4は、感光ドラム39との対向位置
の近傍でDCバイアスにACバイアスを重畳した現像バ
イアスを現像スリーブ42に印加することにより、周知
の2成分磁気ブラシ現像法により感光ドラム39の静電
潜像を現像する。これにより現像剤4中の非磁性トナー
が潜像に付着し、潜像がトナー像として可視化される。
The respective developing steps will be described below. First, in the upstream developing chamber 40A, the developer 4 is stirred by the stirring screw 44 and supplied to the developing sleeve 42 in which the magnet 42a is fixedly arranged, and the developer 4 is carried on the surface of the developing sleeve 42. Then, the developer is conveyed toward the photosensitive drum 39, and the amount of the developer is regulated to an appropriate amount by the doctor blade 46 during the conveyance. The developer 4 conveyed toward the photosensitive drum 39 is applied to the developing sleeve 42 by applying a developing bias in which an AC bias is superimposed on a DC bias in the vicinity of a position facing the photosensitive drum 39, thereby forming a known two-component magnetic brush. The electrostatic latent image on the photosensitive drum 39 is developed by a developing method. As a result, the non-magnetic toner in the developer 4 adheres to the latent image, and the latent image is visualized as a toner image.

【0019】次に、下流側の現像室40Bでは、搬送ロ
ーラ45によって非磁性1成分現像剤、つまり非磁性ト
ナー5を弾性ローラ48に向けて搬送し、その非磁性ト
ナー5を付着とはぎ取りを兼ねた弾性ローラ48により
非磁性の現像スリーブ43の表面に担持させ、現像スリ
ーブ43により感光ドラム39に向けて搬送する。トナ
ー5はその搬送途上において弾性ブレード47により適
正なトナー量に規制される。感光ドラム39に向けて搬
送された非磁性トナー5は、感光ドラム39との対向位
置の近傍でDCバイアスにACバイアスを重畳した現像
バイアスを現像スリーブ43に印加することにより、周
知の非磁性1成分現像法により感光ドラム39の一度現
像された静電潜像を現像する。これによりトナー5が潜
像に付着し、潜像が更に現像される。
Next, in the downstream developing chamber 40B, the non-magnetic one-component developer, that is, the non-magnetic toner 5 is conveyed toward the elastic roller 48 by the conveying roller 45, and the non-magnetic toner 5 is adhered and stripped. It is carried on the surface of the non-magnetic developing sleeve 43 by the elastic roller 48 which also serves as a carrier, and is conveyed toward the photosensitive drum 39 by the developing sleeve 43. The toner 5 is regulated to an appropriate amount by the elastic blade 47 during the conveyance. The non-magnetic toner 5 conveyed toward the photosensitive drum 39 is applied to the developing sleeve 43 by applying a developing bias in which an AC bias is superimposed on a DC bias in the vicinity of a position facing the photosensitive drum 39, thereby obtaining a known non-magnetic toner 5. The electrostatic latent image once developed on the photosensitive drum 39 is developed by the component developing method. As a result, the toner 5 adheres to the latent image, and the latent image is further developed.

【0020】このように、本実施例では、下流側の現像
室40Bによる第2の現像工程を非磁性1成分現像法と
したので、従来、第2の現像工程で発生していたスキャ
ベジング現象、つまりキャリアによる画像の機械的、静
電気的な掻き取り自体を生じることがない。従って、多
段現像方式による現像性の向上と画像後端部の白抜けな
どを防ぐ効果を維持したまま、画像乱れを防いで、高品
質な画像を得ることができる。
As described above, in the present embodiment, since the second developing step in the downstream developing chamber 40B is a non-magnetic one-component developing method, the scavenging phenomenon which has conventionally occurred in the second developing step can be achieved. That is, mechanical and electrostatic scraping of the image itself by the carrier does not occur. Therefore, it is possible to obtain a high-quality image by preventing image disorder while maintaining the effect of improving the developability by the multi-stage developing method and preventing the occurrence of white spots at the rear end of the image.

【0021】実施例2 本発明の他の実施例を図3に基づいて説明する。図1〜
図2に示した実施例1では、現像装置40の現像室40
Aに2成分現像剤4、現像室40Bに1成分現像剤5と
いうように、2種類の現像剤を用いたが、本実施例で
は、現像室40Bにも2成分現像剤4を用いた。下流側
の現像室40Bには、実施例1の弾性ローラ48の代わ
りに、内部に図示しない磁石が固定配設されたトナー供
給スリーブ50が設置され、また現像スリーブ43に対
する弾性ブレード47の代わりに、トナー供給スリーブ
50に対する磁性のドクターブレード49が設置されて
いる。
Embodiment 2 Another embodiment of the present invention will be described with reference to FIG. Figure 1
In the first embodiment shown in FIG.
Although two types of developers were used, such as a two-component developer 4 for A and a one-component developer 5 for the developing chamber 40B, the two-component developer 4 was also used for the developing chamber 40B in this embodiment. In the downstream developing chamber 40B, instead of the elastic roller 48 of the first embodiment, a toner supply sleeve 50 in which a magnet (not shown) is fixedly provided is installed. Further, instead of the elastic blade 47 for the developing sleeve 43, a toner supply sleeve 50 is provided. A magnetic doctor blade 49 for the toner supply sleeve 50 is provided.

【0022】本実施例において、上流側の現像室40A
による第1の現像工程は、実施例1と同様の過程を経て
行なわれる。
In this embodiment, the upstream developing chamber 40A
Is performed through the same process as in the first embodiment.

【0023】下流側の現像室40Bによる第2の現像工
程は、次のように行なわれる。すなわち、下流側の現像
室40Bでは、搬送ローラ45によって2成分現像剤4
をトナー供給スリーブ50に搬送し、その現像剤4を磁
石を内蔵したトナー供給スリーブ50の表面に担持し
て、現像スリーブ43に向けて搬送する。その搬送途上
においてドクターブレード49により、現像剤4を適正
な現像剤量に規制した後、周知の2成分磁気ブラシ法に
よりその現像剤4中の非磁性トナー5を非磁性の現像ス
リーブ43に供給し、担持させる。現像スリーブ43に
担持された非磁性トナー5は感光ドラム39に向けて搬
送され、感光ドラム39との対向位置の近傍でDCバイ
アスにACバイアスを重畳した現像バイアスを現像スリ
ーブ43に印加することにより、非磁性1成分現像法に
より感光ドラム39の一度現像された静電潜像を現像す
る。これによりトナー5が潜像に付着し、潜像が更に現
像される。
The second developing step in the downstream developing chamber 40B is performed as follows. That is, in the downstream developing chamber 40 </ b> B, the two-component developer 4
Is transported to the toner supply sleeve 50, and the developer 4 is carried on the surface of the toner supply sleeve 50 having a built-in magnet, and is transported toward the developing sleeve 43. After regulating the developer 4 to an appropriate amount by the doctor blade 49 during the conveyance, the non-magnetic toner 5 in the developer 4 is supplied to the non-magnetic developing sleeve 43 by a well-known two-component magnetic brush method. And carry it. The non-magnetic toner 5 carried on the developing sleeve 43 is conveyed toward the photosensitive drum 39, and a developing bias in which an AC bias is superimposed on a DC bias is applied to the developing sleeve 43 in the vicinity of a position facing the photosensitive drum 39. The electrostatic latent image once developed on the photosensitive drum 39 is developed by a non-magnetic one-component developing method. As a result, the toner 5 adheres to the latent image, and the latent image is further developed.

【0024】以上のように、本実施例では、下流側の現
像室40Bに2成分現像剤4を用いたが、その2成分現
像剤から非磁性トナーを現像スリーブ43に供給して、
第2の現像工程を非磁性1成分現像法で行なわせたの
で、実施例1のときと同様、キャリアによるスキャベジ
ング現象がなく、多段現像方式による現像性の向上と画
像後端部の白抜けなどを防ぐ効果を維持したまま、画像
乱れを防いで、高品質な画像を得ることができる。ま
た、本実施例では、2成分現像剤のみを使用したので、
現像装置40への現像剤補給機構を簡易な構成にするこ
とができ、上記の効果を実施例1と比べて低コストで達
成することができる。
As described above, in this embodiment, the two-component developer 4 is used in the downstream developing chamber 40B, but the non-magnetic toner is supplied to the developing sleeve 43 from the two-component developer.
Since the second developing step was performed by the non-magnetic one-component developing method, there was no scavenging phenomenon due to the carrier, as in the case of Example 1, and the multi-stage developing method improved the developability and caused a white spot at the rear end of the image. It is possible to obtain a high-quality image by preventing image disturbance while maintaining the effect of preventing the image. In this embodiment, since only the two-component developer was used,
The mechanism for supplying the developer to the developing device 40 can be simplified, and the above effects can be achieved at lower cost than in the first embodiment.

【0025】実施例3 図4は、本発明の他の実施例における現像装置を示す概
略構成図である。本実施例は、図3の現像装置におい
て、トナー供給スリーブ50を省略し、その代わりに、
図4に示すように、下流側の現像室40Bの現像スリー
ブ43の内部に磁石43aを固定配設し、上流側の現像
室40Aの現像スリーブ42内の磁石42aと対向する
磁石43aの対向位置の近傍に、反撥磁極(本例では磁
極S、S)を設けたことが大きな特徴である。ドクター
ブレード49は現像スリーブ43に対し配設した。また
現像スリーブ43の表面は、トナーを担持しやすいよう
に、表面粗さRz=3μm程度の粗面としている。
Embodiment 3 FIG. 4 is a schematic structural view showing a developing device according to another embodiment of the present invention. In the present embodiment, the toner supply sleeve 50 is omitted in the developing device of FIG.
As shown in FIG. 4, a magnet 43a is fixedly arranged inside the developing sleeve 43 of the downstream developing chamber 40B, and the facing position of the magnet 43a facing the magnet 42a in the developing sleeve 42 of the upstream developing chamber 40A. Is characterized by providing repelling magnetic poles (magnetic poles S, S in this example) in the vicinity of. The doctor blade 49 was provided for the developing sleeve 43. Further, the surface of the developing sleeve 43 is a rough surface having a surface roughness Rz of about 3 μm so as to easily carry the toner.

【0026】本実施例において、上流側の現像室40A
による第1の現像工程は、実施例2(従って、実施例
1)と同様の過程を経て行なわれる。次に、第2の現像
工程を行なう下流側の現像室40Bでは、搬送ローラ4
5により搬送された2成分現像剤4を、磁石43aを内
蔵した現像スリーブ43に担持して搬送する。現像剤4
は、ドクターブレード49により現像剤量を規制された
後、上流側の現像室40Aの現像スリーブ42との対向
位置の近傍において、現像スリーブ43内の磁石43a
の反撥磁極S、Sにより、現像剤4中のキャリアの担持
力が緩められ、キャリアが上流側の現像スリーブ42に
引き付けられて移行する。従って、下流側の現像スリー
ブ43には現像剤4中の非磁性トナー5のみが残り、感
光ドラム39の潜像の更なる現像を非磁性1成分現像法
で行なうことができる。
In this embodiment, the upstream developing chamber 40A
Is carried out through the same process as in Example 2 (accordingly, Example 1). Next, in the developing chamber 40B on the downstream side where the second developing step is performed, the transport rollers 4
The two-component developer 4 conveyed by 5 is carried on a developing sleeve 43 containing a magnet 43a. Developer 4
After the amount of the developer is regulated by the doctor blade 49, the magnet 43a in the developing sleeve 43 is located near the position where the upstream developing chamber 40A faces the developing sleeve 42.
Due to the repelling magnetic poles S, the carrier holding force in the developer 4 is relaxed, and the carrier is attracted to the upstream developing sleeve 42 and shifts. Therefore, only the non-magnetic toner 5 in the developer 4 remains on the downstream developing sleeve 43, and the latent image on the photosensitive drum 39 can be further developed by the non-magnetic one-component developing method.

【0027】以上のように、本実施例では、実施例2の
ようなトナー供給ローラ50を用いないで済むので、実
施例2と同等の効果を得ることができるとともに、装置
の小型化、より低コスト化が可能となる。
As described above, in this embodiment, it is not necessary to use the toner supply roller 50 as in the second embodiment, so that the same effects as those of the second embodiment can be obtained, and the size of the apparatus can be reduced. The cost can be reduced.

【0028】[0028]

【発明の効果】以上説明したように、本発明によれば、
像担持体の移動方向にそって、現像剤担持体を備えた2
つの現像室を有する現像装置により、像担持体に形成し
た同一静電潜像を重ねて現像するに際し、一方の現像室
による2成分現像剤を用いた2成分磁気ブラシ現像方式
の現像後、他方の現像室による現像を、非磁性トナーの
みからなる非磁性1成分現像方式で行なったので、第2
の現像工程で発生していたキャリアが画像を機械的、静
電気的に掻き取るスキャベジング自体を生じることがな
く、多段現像方式による現像性の向上と画像後端部の白
抜けなどを防ぐ効果を維持したまま、画像乱れを防い
で、高品質な画像を得ることができる。
As described above, according to the present invention,
2 provided with a developer carrier along the moving direction of the image carrier.
When the same electrostatic latent image formed on the image bearing member is superimposed and developed by a developing device having two developing chambers, after the development using a two-component magnetic brush developing method using a two-component developer in one developing chamber, the other is performed. Since the development in the developing chamber was performed by the non-magnetic one-component developing method including only the non-magnetic toner,
The carrier generated during the development process does not cause scavenging itself, which mechanically and electrostatically scrapes the image, maintaining the effect of improving the developability by multi-stage development and preventing white spots at the trailing edge of the image As a result, a high-quality image can be obtained while preventing image disturbance.

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

【図1】本発明の画像形成装置の一実施例の概略構成を
示す断面図である。
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an embodiment of an image forming apparatus according to the present invention.

【図2】図1の画像形成装置に設置された現像装置の概
略構成を示す断面図である。
FIG. 2 is a cross-sectional view illustrating a schematic configuration of a developing device installed in the image forming apparatus of FIG.

【図3】本発明の他の実施例における現像装置の概略構
成を示す断面図である。
FIG. 3 is a cross-sectional view illustrating a schematic configuration of a developing device according to another embodiment of the present invention.

【図4】本発明の更に他の実施例における現像装置の概
略構成を示す断面図である。
FIG. 4 is a cross-sectional view illustrating a schematic configuration of a developing device according to still another embodiment of the present invention.

【符号の説明】[Explanation of symbols]

4 2成分現像剤 5 非磁性トナー 39 感光ドラム 40 現像装置 42、43 現像スリーブ 42a、43a 磁石 42A、43A 現像室 47 弾性ブレード 48 弾性ローラ 49 ドクターブレード 50 トナー供給スリーブ Reference Signs List 4 two-component developer 5 nonmagnetic toner 39 photosensitive drum 40 developing device 42, 43 developing sleeve 42a, 43a magnet 42A, 43A developing chamber 47 elastic blade 48 elastic roller 49 doctor blade 50 toner supply sleeve

───────────────────────────────────────────────────── フロントページの続き (72)発明者 長谷川 和弘 東京都大田区下丸子3丁目30番2号 キヤ ノン株式会社内 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Hasegawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (6)

【特許請求の範囲】[Claims] 【請求項1】 現像装置が像担持体の移動方向にそっ
て、現像剤担持体を備えた2つの現像室を有し、像担持
体に形成した静電潜像を一方の現像室により現像し、そ
の同一静電潜像を他方の現像室により更に現像する画像
形成装置において、前記一方の現像室による現像は、非
磁性トナーと磁性キャリアとを混合した2成分現像剤に
よる2成分磁気ブラシ現像方式であり、他方の現像室に
よる現像は、非磁性トナーのみからなる1成分現像剤に
よる非磁性1成分現像方式であることを特徴とする画像
形成装置。
A developing device has two developing chambers provided with a developer carrier along a moving direction of the image carrier, and develops an electrostatic latent image formed on the image carrier by one developing chamber. In the image forming apparatus for further developing the same electrostatic latent image by the other developing chamber, the developing by the one developing chamber may be performed by a two-component magnetic brush using a two-component developer obtained by mixing a non-magnetic toner and a magnetic carrier. An image forming apparatus, wherein the image forming apparatus is a non-magnetic one-component developing method using a one-component developer made of only a non-magnetic toner.
【請求項2】 前記他方の現像室に非磁性トナーのみか
らなる1成分現像剤が収容され、前記他方の現像室は弾
性部材からなる現像剤供給部材を有し、この現像剤供給
部材が現像剤担持体に当接して移動することにより、前
記非磁性トナーを現像剤担持体に担持させる請求項1の
画像形成装置。
2. The one-component developer containing only non-magnetic toner is contained in the other developing chamber, and the other developing chamber has a developer supply member composed of an elastic member. The image forming apparatus according to claim 1, wherein the nonmagnetic toner is carried on the developer carrier by moving while contacting the developer carrier.
【請求項3】 前記他方の現像室に非磁性トナーと磁性
キャリアとを混合した2成分現像剤が収容され、前記他
方の現像室は磁石を内蔵した現像剤供給部材を有し、こ
の現像剤供給部材が前記現像剤を担持すると共に、現像
剤中の非磁性トナーを磁気ブラシ方式により前記他方の
現像室の現像剤担持体に担持させる請求項1の画像形成
装置。
3. The other developing chamber contains a two-component developer in which a non-magnetic toner and a magnetic carrier are mixed, and the other developing chamber has a developer supply member having a built-in magnet. 2. The image forming apparatus according to claim 1, wherein a supply member carries the developer, and a non-magnetic toner in the developer is carried on a developer carrier of the other developing chamber by a magnetic brush method.
【請求項4】 前記他方の現像室に非磁性トナーと磁性
キャリアとを混合した2成分現像剤が収容され、前記他
方の現像室の現像剤担持体は、前記一方の現像室の現像
剤担持体との対向部に少なくとも反撥磁極を有する磁石
を内蔵し、この他方の現像室の現像剤担持体が現像剤を
担持すると共に、前記一方の現像室の現像剤担持体との
対向部において現像剤中のキャリアに対する磁気拘束力
を弱め、現像剤中の非磁性トナーを残留してキャリアだ
けを前記一方の現像室の現像剤担持体に移行させること
により、前記他方の現像室の現像剤担持体が非磁性トナ
ーを担持する請求項1の画像形成装置。
4. The two-component developer in which a non-magnetic toner and a magnetic carrier are mixed is accommodated in the other developing chamber, and the developer carrying member of the other developing chamber carries the developer carrying material of the one developing chamber. A magnet having at least a repelling magnetic pole is built in a portion facing the body, and the developer carrier of the other developing chamber carries the developer, and the developer is developed at the portion of the one developing chamber facing the developer carrier. By weakening the magnetic binding force on the carrier in the developer, leaving the non-magnetic toner in the developer and transferring only the carrier to the developer carrying member in the one developing chamber, the developer carrying in the other developing chamber is reduced. The image forming apparatus according to claim 1, wherein the body carries a non-magnetic toner.
【請求項5】 前記一方の現像室が像担持体の移動方向
の上流側に設置され、他方の現像室が像担持体の移動方
向の下流側に設置された請求項1〜4のいずれかの項に
記載の画像形成装置。
5. The image forming apparatus according to claim 1, wherein said one developing chamber is installed on the upstream side in the moving direction of the image carrier, and the other developing chamber is installed on the downstream side in the moving direction of the image carrier. The image forming apparatus according to the item.
【請求項6】 前記一方の現像室による現像時、その現
像剤担持体にDCバイアスにACバイアスを重畳した現
像バイアスが印加され、前記他方の現像室の現像時、そ
の現像剤担持体にDCバイアスにACバイアスを重畳し
た現像バイアスが印加される請求項1〜5のいずれかの
項に記載の画像形成装置。
6. A developing bias in which an AC bias is superimposed on a DC bias is applied to the developer carrying member during development by the one developing chamber, and a DC bias is applied to the developer carrying member during development in the other developing chamber. The image forming apparatus according to claim 1, wherein a developing bias in which an AC bias is superimposed on the bias is applied.
JP34243396A 1996-12-06 1996-12-06 Image forming device Pending JPH10171252A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP34243396A JPH10171252A (en) 1996-12-06 1996-12-06 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP34243396A JPH10171252A (en) 1996-12-06 1996-12-06 Image forming device

Publications (1)

Publication Number Publication Date
JPH10171252A true JPH10171252A (en) 1998-06-26

Family

ID=18353707

Family Applications (1)

Application Number Title Priority Date Filing Date
JP34243396A Pending JPH10171252A (en) 1996-12-06 1996-12-06 Image forming device

Country Status (1)

Country Link
JP (1) JPH10171252A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006284966A (en) * 2005-03-31 2006-10-19 Canon Inc Image forming apparatus
US7653336B2 (en) 2005-09-07 2010-01-26 Canon Kabushiki Kaisha Developing apparatus featuring multiple magnetic rollers for developing a latent image multiple times
US8369754B2 (en) 2008-07-11 2013-02-05 Konica Minolta Business Technologies, Inc. Developing device and image forming apparatus
US8941901B2 (en) 2013-01-28 2015-01-27 Ricoh Company, Ltd. Electrophotographic image output device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006284966A (en) * 2005-03-31 2006-10-19 Canon Inc Image forming apparatus
JP4642529B2 (en) * 2005-03-31 2011-03-02 キヤノン株式会社 Development device
US7653336B2 (en) 2005-09-07 2010-01-26 Canon Kabushiki Kaisha Developing apparatus featuring multiple magnetic rollers for developing a latent image multiple times
US7853186B2 (en) 2005-09-07 2010-12-14 Canon Kabushiki Kaisha Developing apparatus featuring multiple magnetic rollers
US8369754B2 (en) 2008-07-11 2013-02-05 Konica Minolta Business Technologies, Inc. Developing device and image forming apparatus
US8941901B2 (en) 2013-01-28 2015-01-27 Ricoh Company, Ltd. Electrophotographic image output device

Similar Documents

Publication Publication Date Title
US4811046A (en) Tri-level highlight color printing apparatus with cycle-up and cycle-down control
JPS6212510B2 (en)
JPH09288426A (en) Image forming device
JP3057121B2 (en) Image forming device
EP0515053A2 (en) Colour electrophotographic method and apparatus employed therefor
JP2002082527A (en) Developing device and image forming device
US4609280A (en) Xerographic apparatus and process with backside photoconductor imaging
JPH10171252A (en) Image forming device
US6032014A (en) Method of using an image forming apparatus
US5140936A (en) Development apparatus having means for partially skiving magnetic developer
JP2006146216A (en) Carrier bead pickoff device
JPH05265271A (en) Color image forming device capable of switching driving speed
JP2004333709A (en) Developing device
JP4077202B2 (en) Image forming apparatus
JPS6232470B2 (en)
JPS6232469B2 (en)
JP3071672B2 (en) Developing device and image forming device
JPH07248705A (en) Image forming device
JPH11109756A (en) Image forming device
JPH11237772A (en) Electrophotographic device
JP3234164B2 (en) Image forming device
JPH1184882A (en) Image forming device
JP4312433B2 (en) Developer and image forming apparatus
JP2002372852A (en) Image forming device
JP4340406B2 (en) Image forming apparatus