JP2000305359A - Developing device and image forming device - Google Patents

Developing device and image forming device

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Publication number
JP2000305359A
JP2000305359A JP11109812A JP10981299A JP2000305359A JP 2000305359 A JP2000305359 A JP 2000305359A JP 11109812 A JP11109812 A JP 11109812A JP 10981299 A JP10981299 A JP 10981299A JP 2000305359 A JP2000305359 A JP 2000305359A
Authority
JP
Japan
Prior art keywords
developer
conveying member
stirring
developer stirring
developing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP11109812A
Other languages
Japanese (ja)
Other versions
JP4093677B2 (en
Inventor
Satohiko Baba
聡彦 馬場
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
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 Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP10981299A priority Critical patent/JP4093677B2/en
Publication of JP2000305359A publication Critical patent/JP2000305359A/en
Application granted granted Critical
Publication of JP4093677B2 publication Critical patent/JP4093677B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can make the quantity of toner electrification uniform and can maintain the toner concentration on a developing sleeve constant, and to provide an image forming device with no unevenness in image density and that can stably obtain a good image. SOLUTION: In this device, the handing over of developer from a 2nd developer agitating and carrying member 3 side to a 1st developer agitating and carrying member 2 side is prompted by distribution of magnetic density of a fixed magnet 4a of a developer carrier 4, circulation of the developer between the 2 pieces of developer agitating and carrying members 2 and 3 is realized and at the same time, a developer carrying path where the developer on the developing sleeve 4b which developer is passed a developing range is dropped to the 2nd developer agitating and carrying member 3 side is provided. The toner electrification quantity and the tone concentration on the developing sleeve 4 are made uniform by the above 2 developer circulating paths.

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、複写機、プリンタ
ー、ファクシミリ等に用いられ、トナーとキャリアとか
ら成る二成分現像剤によって静電潜像の現像を行う現像
装置、並びにこのような現像装置を有し、画像形成を行
う画像形成装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for use in a copying machine, a printer, a facsimile, etc., for developing an electrostatic latent image with a two-component developer comprising a toner and a carrier, and such a developing device. And an image forming apparatus for forming an image.

【０００２】[0002]

【従来の技術】一般にトナーとキャリアとから成る二成
分現像剤を用いる現像方法では、トナー粒子と磁性体か
ら成るキャリア粒子とを機械的に攪拌することにより、
トナー粒子とキャリア粒子とを互いに逆の極性に帯電さ
せる。これらの粒子は、静電気的付着力により一体とな
っているが、感光体上の静電潜像に接近すると、トナー
粒子とキャリア粒子とが引き合う静電気力よりも強い静
電気力によって、トナー粒子が静電潜像側へ引かれ、潜
像が可視像化される。この時、トナー濃度は形成される
画像に大きな影響を与える。トナー濃度が低い場合、画
像濃度の低下を引き起こす。逆に、トナー濃度が高い場
合は、画像濃度が高くなると同時に地肌汚れが発生しや
すくなる。また、現像を行うと、トナーのみが感光体に
転移して消費され、キャリアは現像装置内にとどまるた
め、消費された分のトナーを新たに補給して現像装置内
のトナー濃度を一定に保つ必要がある。2. Description of the Related Art Generally, in a developing method using a two-component developer composed of a toner and a carrier, a toner particle and a carrier particle composed of a magnetic material are mechanically stirred.
The toner particles and the carrier particles are charged to polarities opposite to each other. These particles are united by electrostatic adhesion, but when approaching the electrostatic latent image on the photoreceptor, the toner particles become static due to the electrostatic force stronger than the electrostatic force attracting the toner particles and the carrier particles. The latent image is drawn to the electro-latent image side, and the latent image is visualized. At this time, the toner density has a great effect on the formed image. When the toner density is low, the image density is reduced. Conversely, when the toner density is high, the background density is easily generated at the same time as the image density increases. Further, when the development is performed, only the toner is transferred to the photoconductor and consumed, and the carrier remains in the developing device. Therefore, the consumed toner is newly replenished and the toner concentration in the developing device is kept constant. There is a need.

【０００３】また、上述した現像では、静電潜像が形成
された感光体と電気的バイアスが印加された現像スリー
ブとの間の電界により、感光体上の潜像形成部に帯電さ
れたトナーが選択的に付着して現像が行われるため、ト
ナーの帯電量が画像の形成に大きな影響を与える。トナ
ーの帯電量が低いと、キャリアとの静電的付着力が小さ
いため、現像剤の中でトナーが浮遊しやすく、また、静
電潜像と現像バイアスとから受ける拘束力も小さいた
め、地肌汚れの発生する割合は増加する。逆に、トナー
の帯電量が高すぎると、トナーとキャリアとの静電的付
着力は強化され、静電潜像に付着するトナー量は少なく
なり、このため画像濃度が低下する。したがって、上記
のような二成分現像剤を用いる画像形成装置において高
画質の画像を形成するには、トナーを均一に帯電し、且
つ均一なトナー濃度の現像剤を現像領域に搬送する必要
がある。In the above-described development, the toner charged on the latent image forming portion on the photoconductor by an electric field between the photoconductor on which the electrostatic latent image is formed and the developing sleeve to which an electric bias is applied. Is selectively adhered and development is performed, so that the charge amount of the toner has a great effect on image formation. If the charge amount of the toner is low, the toner is likely to float in the developer because the electrostatic adhesion to the carrier is small, and the binding force received from the electrostatic latent image and the developing bias is also small. The rate of occurrence increases. Conversely, if the charge amount of the toner is too high, the electrostatic adhesion between the toner and the carrier is strengthened, and the amount of toner adhering to the electrostatic latent image is reduced, thereby lowering the image density. Therefore, in order to form a high-quality image in the image forming apparatus using the two-component developer as described above, it is necessary to uniformly charge the toner and transport the developer having a uniform toner concentration to the developing area. .

【０００４】ここで、従来の現像装置によるトナーの帯
電方法及びトナー濃度調整方法について説明する。図１
１及び図１２に、従来の現像装置を示す。この現像装置
５９においては、スクリュー形状から成る第１現像剤攪
拌搬送部材５２と第２現像剤攪拌搬送部材５３とが仕切
り板５５を挟んで平行に配置され、トナーとキャリアと
から成る現像剤を混合攪拌しながら互いに反対の方向に
搬送し、循環させる。第１現像剤攪拌搬送部材５２と第
２現像剤攪拌搬送部材５３との対向部の反対側には、現
像剤担持体５４が２つの現像剤攪拌部材５２、５３と平
行に配置されており、第１現像剤攪拌搬送部材５２側か
ら汲み上げた現像剤を表面に付着させ、回転に伴い搬送
する。現像剤担持体５４は、内部に磁界発生手段である
固定された磁石５４ａ及びその外側に非磁性材料で構成
され、矢印の方向に回転可能に支持された現像スリーブ
５４ｂとを有する。現像剤担持体５４の周囲の、現像剤
担持体５４が感光体と対向する現像領域の上流には、ア
ルミニウム、ＳＵＳ等の非磁性材料で構成された現像ド
クタ５６が現像スリーブ５４ｂと所定の間隔を設けて取
り付けられており、現像スリーブ５４ｂ上の現像剤は、
現像スリーブ５４ｂの回転によって現像ドクタ５６との
対向位置を通過する時所定の量に規制される。現像剤
は、現像ドクタ５６通過の際強いストレスを受けてトナ
ーが帯電され、現像領域に搬送される。現像領域では、
表面に静電潜像が形成された感光体と電気的バイアスが
印加された現像スリーブ５４ｂとの間の電界の作用で、
感光体上の静電潜像が帯電されたトナーにより顕像化さ
れる。Here, a description will be given of a toner charging method and a toner density adjusting method using a conventional developing device. FIG.
1 and 12 show a conventional developing device. In the developing device 59, a first developer stirring and conveying member 52 having a screw shape and a second developer stirring and conveying member 53 are arranged in parallel with a partition plate 55 interposed therebetween. While mixing and agitating, they are transported in opposite directions and circulated. On the opposite side of the facing portion between the first developer stirring and conveying member 52 and the second developer stirring and conveying member 53, a developer carrier 54 is arranged in parallel with the two developer stirring members 52 and 53, The developer pumped up from the first developer stirring and transporting member 52 is adhered to the surface, and transported with rotation. The developer carrier 54 has a fixed magnet 54a, which is a magnetic field generating means, inside, and a developing sleeve 54b, which is made of a non-magnetic material and is rotatably supported in the direction of the arrow, outside thereof. A developing doctor 56 made of a non-magnetic material such as aluminum or SUS is provided with a predetermined distance from the developing sleeve 54b around the developer carrier 54 and upstream of a developing area where the developer carrier 54 faces the photoconductor. The developer on the developing sleeve 54b is
By the rotation of the developing sleeve 54b, the amount is regulated to a predetermined amount when passing through the position facing the developing doctor 56. The developer receives a strong stress when passing through the developing doctor 56, charges the toner, and is conveyed to the developing area. In the development area,
By the action of an electric field between the photoreceptor having an electrostatic latent image formed on the surface and the developing sleeve 54b to which an electric bias has been applied,
The electrostatic latent image on the photoconductor is visualized by the charged toner.

【０００５】贋造領域を通過した後消費されなかったト
ナーを含む現像剤は、現像剤担持体５４の内部に固定さ
れた磁石５４ａにより形成された現像剤剥離極で現像ス
リーブ５４ｂから脱落し、第１現像剤攪拌搬送部材５２
に戻され、第１現像剤攪拌搬送部材５２上を現像剤循環
下流方向へ搬送される。そして、現像剤は上記と同様の
課程を繰り返しながら、第１現像剤攪拌搬送部材５２と
第２現像剤攪拌搬送部材５３との間を循環し、再び現像
スリーブ５４ｂ上に汲み上げられる。第２現像剤攪拌搬
送部材５３側にはトナー濃度検知センサ５７が設置さ
れ、現像装置内のトナー濃度を検知する。このトナー濃
度の検知結果が設定されたトナー濃度より低い場合は、
図示しないトナー補給装置から矢印Ａの経路で第２現像
剤攪拌搬送部材５３の循環上流側にトナーを補給する。
補給されたトナーは、第２現像剤攪拌搬送部材５３と第
１現像剤攪拌搬送部材５２とにより現像剤搬送路内を循
環しながら、現像装置内の現像剤と混合攪拌される。ト
ナー補給部からのトナーの補給量は、トナー濃度検知セ
ンサ５７からの信号に基づいて制御され、現像装置内の
トナー濃度が設定濃度付近に維持される。そして、この
行程を繰り返すことにより、現像装置内のトナー濃度を
常に設定濃度付近に維持するように構成されている。The developer containing toner that has not been consumed after passing through the counterfeit area falls off the developing sleeve 54 b at a developer peeling pole formed by a magnet 54 a fixed inside the developer carrier 54, 1 developer stirring transport member 52
And is conveyed on the first developer stirring and conveying member 52 in the developer circulation downstream direction. Then, the developer circulates between the first developer stirring and conveying member 52 and the second developer stirring and conveying member 53 while repeating the same process as described above, and is again pumped onto the developing sleeve 54b. A toner concentration detection sensor 57 is provided on the side of the second developer stirring and conveying member 53 to detect the toner concentration in the developing device. If this toner density detection result is lower than the set toner density,
The toner is supplied from a toner supply device (not shown) to the upstream side of the circulation of the second developer stirring / conveying member 53 along a path indicated by an arrow A.
The replenished toner is mixed and stirred with the developer in the developing device while being circulated in the developer conveying path by the second developer stirring and conveying member 53 and the first developer stirring and conveying member 52. The toner replenishment amount from the toner replenishment unit is controlled based on a signal from the toner density detection sensor 57, and the toner density in the developing device is maintained near the set density. By repeating this process, the toner density in the developing device is always maintained near the set density.

【０００６】画像濃度を安定化する方法としては、現像
剤攪拌搬送手段の始端部の現像剤搬送力を他の部分の現
像剤搬送力よりも大きくし、２つの現像剤攪拌搬送手段
間での現像剤の受け渡し効率を向上させることにより、
濃度変動の少ない画像を得る技術が、特開平３−２８２
４８８号公報に開示されている。As a method of stabilizing the image density, the developer conveying force at the start end of the developer agitating / conveying means is made larger than the developer conveying force of the other portions, so that the developer agitating / conveying means is moved between the two developer agitating / conveying means. By improving developer delivery efficiency,
A technique for obtaining an image with little density fluctuation is disclosed in Japanese Patent Laid-Open No. 3-282.
No. 488.

【０００７】[0007]

【発明が解決しようとする課題】しかしながら、上述の
従来の技術には次のような問題がある。従来の現像装置
では、第１現像剤攪拌搬送部材５２の上流側から下流側
へ現像剤が搬送される間にトナーが消費されていくた
め、トナー濃度は第１現像剤攪拌搬送部材５２の下流側
で上流側よりも低くなる。したがって、現像スリーブ５
４ｂに汲み上げられた現像剤のトナー濃度が、現像装置
の長手方向で不均一となり、形成画像の画像濃度ムラが
生じる。特に、画像濃度が高くトナー消費が多い画像で
は、画像濃度ムラは顕著となる。また、現像剤の帯電
は、主として現像スリーブ５４ｂ上に担持され、現像ス
リーブ５４ｂの回転に伴って現像ドクタ５６との間を通
過する時に行われる。この時、第１現像剤攪拌搬送部材
５２側には、現像スリーブ５４ｂ上に汲み上げられ、現
像ドクタ５６と現像スリーブ５４ｂとの間を通過して帯
電量が上昇した現像剤と、現像スリーブ５４ｂ上に汲み
上げられず、帯電量の低い現像剤とが混在する。そし
て、第１現像剤攪拌搬送部材５２の下流側では、上流側
に比べ現像ドクタ５６と現像スリーブ５４ｂとの間の通
過回数の多い現像剤と、通過回数の少ない現像剤との差
が大きくなり、トナー帯電量のバラツキが大きくなる。
前述のように、トナーの帯電量は形成される画像に大き
な影響を与えるため、帯電量の高いトナーと帯電量の低
いトナーとが混在すると、均一な画像が得られなくな
る。However, the above-mentioned prior art has the following problems. In the conventional developing device, the toner is consumed while the developer is conveyed from the upstream side to the downstream side of the first developer agitating / conveying member 52. Side is lower than the upstream side. Therefore, the developing sleeve 5
The toner concentration of the developer pumped up by the developer 4b becomes non-uniform in the longitudinal direction of the developing device, resulting in uneven image density of the formed image. In particular, in an image having a high image density and consuming a large amount of toner, the image density unevenness becomes remarkable. The charge of the developer is mainly carried on the developing sleeve 54b, and is performed when the developer passes between the developing doctor 56 and the developing sleeve 54b. At this time, on the first developer stirring and conveying member 52 side, the developer that has been pumped up onto the developing sleeve 54b and has passed between the developing doctor 56 and the developing sleeve 54b and has an increased charge amount, and And a developer with a low charge amount is mixed. Then, on the downstream side of the first developer stirring and conveying member 52, the difference between the developer having a larger number of passages and the developer having a smaller number of passages between the developing doctor 56 and the developing sleeve 54b is larger than that on the upstream side. As a result, the variation in the toner charge amount increases.
As described above, the charge amount of the toner has a great effect on an image to be formed. Therefore, if a toner having a high charge amount and a toner having a low charge amount coexist, a uniform image cannot be obtained.

【０００８】本発明は、上記のような問題に鑑みて成さ
れたものであり、その目的は、トナー帯電量の均一化を
計り、且つ現像スリーブ上でのトナー濃度を一定に維持
することにより、濃度ムラのない画像を形成することが
可能な現像装置および画像形成装置を提供することであ
る。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make the toner charge amount uniform and maintain the toner concentration on the developing sleeve constant. Another object of the present invention is to provide a developing device and an image forming apparatus capable of forming an image without density unevenness.

【０００９】[0009]

【課題を解決するための手段】上記問題点を解決するた
めに、請求項１に記載の発明は、トナーとキャリアとか
ら成る二成分現像剤を仕切り板を挟んで互いに逆の方向
に攪拌搬送する第１現像剤攪拌搬送部材と第２現像剤攪
拌搬送部材とから成る現像剤攪拌搬送手段と、該現像剤
攪拌搬送手段と平行に配設され、内部に固定された磁石
と、周面上に回転可能に支持された現像スリーブとを備
え、表面に前記二成分現像剤を担持する現像剤担持体と
を有し、像担持体上の静電潜像を可視化する現像装置に
おいて、前記現像剤攪拌搬送手段は、前記第１現像剤攪
拌搬送部材と前記第２現像剤攪拌搬送部材との中間部で
前記現像剤担持体と対向し、前記第１現像剤攪拌搬送部
材が、前記第２現像剤攪拌搬送部材に対して前記現像ス
リーブの回転の下流側に位置するように回転可能に支持
され、 前記磁石は、前記第１現像剤攪拌搬送部材から
現像剤を汲み上げると共に、前記像担持体と対向する現
像領域を通過した現像剤を前記第２現像剤攪拌搬送部材
上に落下させる磁気拘束力を有する現像装置を提供す
る。According to a first aspect of the present invention, a two-component developer comprising a toner and a carrier is agitated and conveyed in opposite directions with a partition plate interposed therebetween. A developer stirring / conveying means comprising a first developer stirring / conveying member and a second developer stirring / conveying member; a magnet disposed in parallel with the developer stirring / conveying means and fixed inside; A developing sleeve rotatably supported by the developing device, and a developer carrier carrying the two-component developer on the surface thereof, wherein the developing device visualizes an electrostatic latent image on the image carrier. A developer agitating / conveying unit that faces the developer carrier at an intermediate portion between the first developer agitating / conveying member and the second developer agitating / conveying member; Under the rotation of the developing sleeve with respect to the developer stirring and conveying member The magnet is adapted to be rotatably supported so as to be positioned on the side, and the magnet pumps up the developer from the first developer stirring / conveying member, and transfers the developer passing through a development area facing the image carrier to the second developer. Provided is a developing device having a magnetic restraining force for dropping on a developer stirring and conveying member.

【００１０】このような現像装置では、現像領域を通過
した現像剤がすべて第２現像剤攪拌搬送部材側に戻され
るため、第１現像剤攪拌搬送部材側の現像剤はすべて現
像に使用されていないリフレッシュ（初期化）状態であ
り、トナー濃度が低下していない。したがって、第１現
像剤攪拌搬送部材側のトナー濃度は、上流側から下流側
にかけて常に一定であり、現像スリーブ上のトナー濃度
に差がなくなるため、濃度差がなく濃度追従性の良い均
一な画像を得ることができる。また、現像領域へ搬送さ
れる現像剤は、充分に攪拌されて第１現像剤攪拌搬送部
材側から汲み上げられ、現像ドクタと対向する領域を一
回だけ通過してきた現像剤であるため、帯電条件が等し
く、帯電量のバラツキが小さくなる。したがって、トナ
ーが均一に帯電されているためトナー飛散や地肌汚れが
なく、細部の画像バラツキのない良質な画像を形成する
ことができる。In such a developing device, all of the developer passing through the developing area is returned to the second developer stirring and conveying member, so that all the developer on the first developer stirring and conveying member is used for development. There is no refresh (initialization) state, and the toner density has not decreased. Therefore, the toner concentration on the first developer stirring and conveying member side is always constant from the upstream side to the downstream side, and there is no difference in the toner concentration on the developing sleeve. Can be obtained. Further, since the developer conveyed to the developing area is sufficiently stirred and pumped up from the first developer stirring and conveying member side, and has passed only once through the area facing the developing doctor, the charging condition And the variation of the charge amount is small. Therefore, since the toner is uniformly charged, it is possible to form a high-quality image free of toner scattering and background contamination, and having no variation in detail.

【００１１】請求項２に記載の発明は、前記第２現像剤
攪拌搬送部材から前記第１現像剤攪拌搬送部材へ現像剤
を受け渡す領域を領域Ｌ、前記現像剤攪拌搬送部材の軸
方向へ現像剤を搬送し、第１現像剤攪拌搬送部材から第
２現像剤攪拌搬送部材へ現像剤を受け渡す領域を領域Ｍ
とするとき、 前記磁石は、前記領域Ｌに対向する領域
に、現像剤を第２現像剤攪拌搬送部材から現像スリーブ
へ汲み上げた後、前記第１現像剤攪拌搬送部材へ受け渡
す磁気拘束力を有し、前記領域Ｍに対向する領域では、
現像剤を保持しないように配置されている請求項１に記
載の現像装置を提供する。According to a second aspect of the present invention, a region for transferring the developer from the second developer stirring and conveying member to the first developer stirring and conveying member is defined as a region L, in the axial direction of the developer stirring and conveying member. A region for conveying the developer and transferring the developer from the first developer stirring and conveying member to the second developer stirring and conveying member is a region M
When the magnet is in a region opposed to the region L, the magnet constrains the magnetic binding force that is transferred to the first developer stirring and conveying member after the developer is pumped from the second developer stirring and conveying member to the developing sleeve. And in a region opposed to the region M,
The developing device according to claim 1, wherein the developing device is arranged so as not to hold the developer.

【００１２】上記のように、領域Ｌ及び領域Ｍの磁束密
度分布が得られるように設定することにより、第１現像
剤攪拌搬送部材−領域Ｌ−第２現像剤攪拌搬送部材−領
域Ｍの現像剤循環経路及び現像スリーブ−第２現像剤攪
拌搬送部材の現像剤循環経路を形成する。このように、
２つの現像剤循環経路を形成することにより、現像領域
を通過した現像剤は直接第１現像剤攪拌搬送部材側に戻
らず、このため、第１現像剤攪拌搬送部材上のトナー濃
度並びに現像スリーブ上のトナー濃度は均一となり、濃
度ムラのない均一な画像を形成することができる。ま
た、第２現像剤攪拌搬送部材上に増量した現像剤を第１
現像剤攪拌搬送部材側へオーバーフローさせ、第２現像
剤攪拌搬送部材側での現像剤詰まりを防止することがで
きる。As described above, by setting so as to obtain the magnetic flux density distribution in the region L and the region M, the development of the first developer stirring and conveying member-region L-the second developer stirring and conveying member-region M is performed. A developer circulation path and a developer circulation path for the developing sleeve and the second developer stirring and conveying member are formed. in this way,
By forming the two developer circulation paths, the developer that has passed through the developing area does not directly return to the first developer stirring and conveying member, and therefore, the toner concentration on the first developer stirring and conveying member and the developing sleeve The upper toner density becomes uniform, and a uniform image without density unevenness can be formed. Further, the increased amount of the developer is put on the second developer stirring and conveying member.
It is possible to prevent the developer from being clogged on the side of the second developer stirring and conveying member by overflowing to the side of the developer stirring and conveying member.

【００１３】請求項３に記載の発明は、前記領域Ｌに前
記現像スリーブから離脱した現像剤を前記第１現像剤攪
拌搬送部材へ誘導する誘導部材を備えた請求項１又は請
求項２に記載の現像装置を提供する。According to a third aspect of the present invention, in the first or second aspect, a guide member for guiding the developer detached from the developing sleeve to the first developer stirring and conveying member is provided in the region L. And a developing device.

【００１４】このように、領域Ｌに現像剤誘導部材を設
けることにより、領域Ｌでの第２現像剤攪拌搬送部材側
から第１現像剤攪拌搬送部材側への現像剤の搬送を確実
に行うことができる。また、領域Ｍでは、現像剤担持体
内部の固定磁石の磁束密度分布を上記のように設定する
ことにより、現像領域通過後の現像剤を現像スリーブか
ら第２攪拌搬送部材上へ落下させる。これにより、２つ
の現像剤循環経路が形成され、第１現像剤攪拌搬送部材
上のトナー濃度及び現像スリーブ上のトナー濃度を均一
化し、濃度ムラのない均一な画像を形成すると共に、第
２現像剤攪拌搬送部材上に増量した現像剤を第１現像剤
攪拌搬送部材側へオーバーフローさせ、第２現像剤攪拌
搬送部材側での現像剤詰まりを防止することができる。As described above, by providing the developer guiding member in the region L, the developer is reliably transferred from the second developer stirring and conveying member side to the first developer stirring and conveying member in the region L. be able to. In the region M, the magnetic flux density distribution of the fixed magnet inside the developer carrier is set as described above, so that the developer after passing through the developing region is dropped from the developing sleeve onto the second stirring and conveying member. As a result, two developer circulation paths are formed, the toner density on the first developer stirring and conveying member and the toner density on the developing sleeve are made uniform, and a uniform image without density unevenness is formed. The increased amount of the developer on the developer agitating / conveying member overflows to the first developer agitating / conveying member side, thereby preventing the developer from being clogged on the second developer agitating / conveying member side.

【００１５】請求項４に記載の発明は、前記第２現像剤
攪拌搬送部材から前記第１現像剤攪拌搬送部材へ現像剤
を受け渡す領域に、現像剤搬送部材を備えた請求項１に
記載の現像装置を提供する。According to a fourth aspect of the present invention, a developer conveying member is provided in an area where the developer is transferred from the second developer stirring and conveying member to the first developer stirring and conveying member. And a developing device.

【００１６】このように、第２現像剤攪拌搬送部材から
第１現像剤攪拌搬送部材への現像剤受け渡し部に搬送部
材を設けることにより、領域Ｌでの第２現像剤攪拌搬送
部材側から第１現像剤攪拌搬送部材側への現像剤の搬送
を円滑に行うことができる。また、領域Ｍでは、現像剤
担持体内部の固定磁石の磁束密度分布を上記のように設
定することにより、現像領域通過後の現像剤を現像スリ
ーブから第２現像剤攪拌搬送部材上へ落下させる。この
ように、２つの現像剤循環経路を形成することにより、
第１現像剤攪拌搬送部材上のトナー濃度及び現像スリー
ブ上のトナー濃度を均一化し、濃度ムラのない均一な画
像を形成すると共に、第２現像剤攪拌搬送部材上に増量
した現像剤を第１現像剤攪拌搬送部材側へオーバーフロ
ーさせ、第２現像剤攪拌搬送部材側での現像剤詰まりを
防止することができる。As described above, by providing the transport member at the developer transfer portion from the second developer agitating / transporting member to the first developer agitating / transporting member, the second developer agitating / transporting member in the region L is moved from the second developer agitating / transporting member side to the first developer agitating / transporting member side. (1) The developer can be smoothly transported to the developer stirring and transporting member side. Further, in the region M, by setting the magnetic flux density distribution of the fixed magnet inside the developer carrying member as described above, the developer after passing through the developing region is dropped from the developing sleeve onto the second developer stirring and conveying member. . Thus, by forming two developer circulation paths,
The toner concentration on the first developer stirring and conveying member and the toner concentration on the developing sleeve are made uniform to form a uniform image without density unevenness, and the increased amount of the developer is transferred onto the second developer stirring and conveying member. It is possible to prevent the developer from being clogged on the side of the second developer stirring and conveying member by overflowing to the side of the developer stirring and conveying member.

【００１７】請求項５に記載の発明は、表面に静電潜像
を形成する感光体と、該感光体の表面を一様に帯電する
帯電手段と、該感光体の表面に露光する露光手段と、ト
ナーとキャリアとから成る二成分現像剤によって前記静
電潜像を現像し、トナー像を形成する現像装置と、該ト
ナー像を記録媒体上に転写する転写装置と、前記記録媒
体上に転写されたトナー像を定着する定着装置と有する
画像形成装置において、 前記現像装置は、トナーとキ
ャリアとから成る二成分現像剤を仕切り板を挟んで互い
に逆の方向に攪拌搬送する第１現像剤攪拌搬送部材と第
２現像剤攪拌搬送部材とから成る現像剤攪拌搬送手段
と、該現像剤攪拌搬送手段と平行に配設され、内部に固
定された磁石と、周面上に回転可能に支持された現像ス
リーブとを備え、表面に前記二成分現像剤を担持する現
像剤担持体とを有し、 前記現像剤攪拌搬送手段は、前
記第１現像剤攪拌搬送部材と前記第２現像剤攪拌搬送部
材との中間部で前記現像剤担持体と対向し、前記第１現
像剤攪拌搬送部材が、前記第２現像剤攪拌搬送部材に対
して前記現像スリーブの回転の下流側に位置するように
回転可能に支持され、 前記磁石は、前記第１現像剤攪
拌搬送部材から現像剤を汲み上げると共に、前記像担持
体と対向する現像領域を通過した現像剤を前記第２現像
剤攪拌搬送部材上に落下させる磁気拘束力を有する画像
形成装置を提供する。According to a fifth aspect of the present invention, there is provided a photoreceptor for forming an electrostatic latent image on a surface thereof, a charging unit for uniformly charging the surface of the photoreceptor, and an exposing unit for exposing the surface of the photoreceptor. A developing device that develops the electrostatic latent image with a two-component developer including a toner and a carrier to form a toner image; a transfer device that transfers the toner image onto a recording medium; An image forming apparatus having a fixing device for fixing a transferred toner image, wherein the developing device stirs and conveys a two-component developer including a toner and a carrier in directions opposite to each other across a partition plate. A developer stirring / conveying means comprising a stirring / conveying member and a second developer stirring / conveying member; a magnet disposed in parallel with the developer stirring / conveying means, fixed inside; and rotatably supported on a peripheral surface. Surface with a developing sleeve A developer carrying member for carrying the two-component developer, wherein the developer stirring and conveying means is configured to perform the developing at an intermediate portion between the first developer stirring and conveying member and the second developer stirring and conveying member. Facing the developer carrier, the first developer stirring and conveying member is rotatably supported with respect to the second developer stirring and conveying member such that the first developer stirring and conveying member is positioned on the downstream side of the rotation of the developing sleeve. Forming an image having a magnetic binding force that draws the developer from the first developer stirring and conveying member and drops the developer that has passed through a developing area facing the image carrier onto the second developer stirring and conveying member; Provide equipment.

【００１８】このような画像形成装置によれば、現像ス
リーブ上のトナー濃度が均一化されているため、均一な
画像形成が可能となる。また、トナーの帯電量が均一で
あるため、トナー飛散や地肌汚れが防止され、濃度ムラ
のない良質の画像形成を行うことが可能となる。さら
に、現像剤担持体と２つの現像剤攪拌搬送部材とが並列
配置されないため、画像形成装置の幅方向の寸法増大を
抑制することができる。According to such an image forming apparatus, since the toner concentration on the developing sleeve is made uniform, a uniform image can be formed. In addition, since the charge amount of the toner is uniform, scattering of the toner and contamination of the background can be prevented, and a high quality image can be formed without density unevenness. Further, since the developer carrier and the two developer stirring and conveying members are not arranged in parallel, it is possible to suppress an increase in the width of the image forming apparatus in the width direction.

【００１９】請求項６に記載の画像形成装置は、前記第
２現像剤攪拌搬送部材から前記第１現像剤攪拌搬送部材
へ現像剤を受け渡す領域を領域Ｌ、前記現像剤攪拌搬送
部材の軸方向へ現像剤を搬送し、第１現像剤攪拌搬送部
材から第２現像剤攪拌搬送部材へ現像剤を受け渡す領域
を領域Ｍとするとき、 前記磁石は、前記領域Ｌに対向
する領域に、現像剤を前記第２現像剤攪拌搬送部材から
汲み上げ、前記第１現像剤攪拌搬送部材へ受け渡す磁気
拘束力を有し、前記領域Ｍに対向する領域では、現像剤
を保持しないように配置されている請求項５に記載の画
像形成装置を提供する。The image forming apparatus according to claim 6, wherein a region for transferring the developer from the second developer stirring and conveying member to the first developer stirring and conveying member is a region L, and a shaft of the developer stirring and conveying member is provided. When the region that conveys the developer in the direction and transfers the developer from the first developer stirring and conveying member to the second developer stirring and conveying member is defined as a region M, the magnet is disposed in a region opposed to the region L. It has a magnetic binding force for pumping up the developer from the second developer stirring and conveying member and transferring it to the first developer stirring and conveying member, and is arranged so as not to hold the developer in a region facing the region M. An image forming apparatus according to claim 5 is provided.

【００２０】このような画像形成装置は、２つの現像剤
循環系を有するため、第１現像剤攪拌搬送部材上のトナ
ー濃度が均一化されると共に現像スリーブ上のトナー濃
度が均一化され、これにより、濃度ムラのない均一な画
像を形成することができる。また、第２現像剤攪拌搬送
部材上の現像剤を第１現像剤攪拌搬送部材側へオーバー
フローさせることにより、第２現像剤攪拌搬送部材上で
増量した現像剤による現像剤詰まりを防止し、現像剤の
均一な帯電量を維持して良好な画像形成を行うことがで
きる。さらに、現像剤担持体と２つの現像剤攪拌搬送部
材とが並列配置されないため、画像形成装置の幅方向の
寸法増大を抑制することができる。Since such an image forming apparatus has two developer circulation systems, the toner concentration on the first developer stirring and conveying member is made uniform and the toner concentration on the developing sleeve is made uniform. Thereby, a uniform image without density unevenness can be formed. Further, by causing the developer on the second developer stirring and conveying member to overflow toward the first developer stirring and conveying member, it is possible to prevent the developer from being clogged with the increased amount of developer on the second developer stirring and conveying member, and Good image formation can be performed while maintaining a uniform charge amount of the agent. Further, since the developer carrier and the two developer stirring and conveying members are not arranged in parallel, it is possible to suppress an increase in the width of the image forming apparatus in the width direction.

【００２１】請求項７に記載の発明は、前記領域Ｌに前
記現像スリーブから離脱した現像剤を前記第１現像剤攪
拌搬送部材へ誘導する誘導部材を備えた請求項５又は請
求項６に記載の画像形成装置を提供する。また、請求項
８に記載の発明は、前記第２現像剤攪拌搬送部材から前
記第１現像剤攪拌搬送部材へ現像剤を受け渡す領域に、
現像剤搬送部材を備えた請求項５に記載の画像形成装置
を提供する。According to a seventh aspect of the present invention, in the region L, a guide member for guiding the developer detached from the developing sleeve to the first developer stirring and conveying member is provided. Image forming apparatus. Further, the invention according to claim 8 is characterized in that an area for transferring a developer from the second developer stirring and conveying member to the first developer stirring and conveying member is provided.
An image forming apparatus according to claim 5, further comprising a developer conveying member.

【００２２】このような構成とすることにより、領域Ｌ
では第２現像剤攪拌搬送部材から第１現像剤攪拌搬送部
材への現像剤の搬送を円滑に行い、領域Ｍでは現像スリ
ーブ上で現像領域を通過した現像剤を第２現像剤攪拌搬
送部材側へ落下させる。このように、２つの現像剤循環
経路を形成することにより、現像スリーブ上のトナー濃
度を均一化し、濃度ムラのない均一な画像を形成すると
共に、第２現像剤攪拌搬送部材での現像剤詰まりを防止
し、均一に帯電させたトナーによる良好な画像形成を行
うことが可能となる。また、このような画像形成装置で
は、現像剤担持体と２つの現像剤攪拌搬送部材とが並列
配置されないため、画像形成装置の幅方向の寸法増大を
抑制することができる。With such a configuration, the area L
Then, the developer is smoothly transported from the second developer agitating / conveying member to the first developer agitating / conveying member. In a region M, the developer passing through the developing area on the developing sleeve is transferred to the second developer agitating / conveying member. Drop to As described above, by forming the two developer circulation paths, the toner density on the developing sleeve is made uniform, a uniform image without density unevenness is formed, and the developer is clogged with the second developer stirring and conveying member. , And a good image can be formed with the uniformly charged toner. Further, in such an image forming apparatus, since the developer carrier and the two developer stirring and conveying members are not arranged in parallel, it is possible to suppress an increase in the width of the image forming apparatus in the width direction.

【００２３】[0023]

【発明の実施の形態】次に、本発明の実施の形態を図に
基づいて説明する。図１は、本発明の画像形成装置の一
実施形態が用いられる複写機を示す概略構成図である。
この複写機は、画像読取装置６０、画像書込装置７０、
画像形成装置８０及び給紙装置９０から構成される。上
記画像形成装置８０は、感光体８１、現像装置８９、転
写手段８５及び定着手段８７から主として構成される。
感光体８１の周りに帯電手段８３、現像剤担持体８４を
含む現像装置８９、転写手段８５、図示しないクリーニ
ング装置及び除電ランプ８２が配置されている。また、
感光体８１の表面には、レーザ駆動装置７１からレーザ
ビーム７３が照射される。上記給紙装置９０は画像形成
装置８０の下側に設置され、着脱可能な給紙カセット９
１内の用紙Ｐは中板で支えられ、図示しないスプリング
によってアームを介して給紙ローラ９２に押し付けられ
る。なお、この画像形成装置８０の裏側には、図示しな
い電源やプリント板（エンジンドライバーボード）等の
電装及び制御装置、あるいはコントローラボードが収容
される。また、現像装置８９の近くには、トナー補給部
が設けられている。Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a copying machine in which an embodiment of the image forming apparatus of the present invention is used.
This copier includes an image reading device 60, an image writing device 70,
It comprises an image forming apparatus 80 and a paper feeder 90. The image forming apparatus 80 mainly includes a photoconductor 81, a developing device 89, a transfer unit 85, and a fixing unit 87.
Around the photoreceptor 81, a charging device 83, a developing device 89 including a developer carrier 84, a transfer device 85, a cleaning device (not shown), and a discharging lamp 82 are arranged. Also,
The surface of the photoconductor 81 is irradiated with a laser beam 73 from a laser driving device 71. The paper feeding device 90 is installed below the image forming apparatus 80 and is detachable from the paper feeding cassette 9.
The sheet P in 1 is supported by a middle plate, and is pressed against the sheet feeding roller 92 via an arm by a spring (not shown). The back side of the image forming apparatus 80 accommodates a power supply, a printed board (engine driver board), and other electrical equipment and a control device, or a controller board (not shown). A toner supply unit is provided near the developing device 89.

【００２４】このような画像形成装置を用いて画像を形
成する場合、まず、帯電手段８３によって感光体８１の
表面が均一に帯電された後、レーザビーム７３が照射さ
れ、静電潜像が形成される。現像装置８９内には、トナ
ーとキャリアとから成る二成分現像剤が収容され、この
現像剤を現像剤担持体８４の表面に担持して感光体８１
と対向する現像領域に搬送し、感光体８１上に形成され
た静電潜像に転移させて可視像を形成する。給紙装置９
０内では、図示しない制御部からの指令により給紙ロー
ラ９２が回転し、給紙カセット９１内の最上位置の記録
紙Ｐが分離パッドで重送されながら下流側のレジストロ
ーラ９６まで搬送され、感光体８１上に形成されたトナ
ー画像と同期するようなタイミングで転写手段８５側に
搬送される。転写手段８５によって感光体８１上の画像
が転写された記録紙Ｐは、さらに搬送されて定着手段８
７の位置に至り、ヒータを内蔵した加熱ローラ８７ａ
と、加熱ローラ８７ａに圧接対向される加圧ローラ８７
ｂとの間を通過し、加熱及び加圧されてトナー像が定着
される。このようにして画像が形成された記録紙Ｐは、
その後排紙ローラによって排紙口から排紙トレイ部８８
上に排出され載置される。When an image is formed by using such an image forming apparatus, first, the surface of the photoreceptor 81 is uniformly charged by the charging means 83 and then irradiated with the laser beam 73 to form an electrostatic latent image. Is done. A two-component developer composed of a toner and a carrier is accommodated in the developing device 89.
Is transferred to a developing area opposite to the photosensitive member 81, and is transferred to an electrostatic latent image formed on the photoconductor 81 to form a visible image. Paper feeder 9
0, the paper feed roller 92 is rotated by a command from a control unit (not shown), and the recording paper P at the uppermost position in the paper feed cassette 91 is conveyed to the downstream registration roller 96 while being multi-fed by the separation pad. The toner is conveyed to the transfer unit 85 at a timing synchronized with the toner image formed on the photoconductor 81. The recording paper P on which the image on the photoreceptor 81 has been transferred by the transfer unit 85 is further conveyed to the fixing unit 8.
7 and a heating roller 87a with a built-in heater
And a pressure roller 87 pressed against the heating roller 87a
b, and is heated and pressed to fix the toner image. The recording paper P on which an image is formed in this way is
Then, the paper is discharged from the paper discharge port to the paper discharge
It is discharged above and placed.

【００２５】（第１の実施形態）上記の画像形成装置に
用いられる本発明の現像装置であり、請求項１に記載の
現像装置の一実施形態について説明する。図２にこの現
像装置の概略構成図を、また、図３には図２に示す現像
装置のＳ−Ｓにおける断面図を示す。この現像装置９
は、開口を有するハウジング内に現像剤担持体４及び現
像剤攪拌搬送手段が収容され、この開口が感光体１と対
向するように設置されている。現像剤担持体４は、内部
に複数の磁石を有し、固定支持されたマグネットローラ
４ａと、その周面上に形成され、矢印の方向に回転可能
に支持された現像スリーブ４ｂとから成り、感光体１と
近接対向するようにハウジングの開口部に配置されてい
る。現像剤担持体４の周面付近の、現像スリーブ４ｂと
感光体１とが対向する現像領域の上流側には、現像スリ
ーブ４ｂ上の現像剤を帯電させる現像ドクタ６が現像ス
リーブ４ｂに近接配置されている。現像剤攪拌搬送手段
は、仕切り板５を隔てて平行に配設されたスクリュー形
状の第１現像剤攪拌搬送部材２と第２現像剤攪拌搬送部
材３とから成る。第１現像剤攪拌搬送部材２は、長手方
向の寸法が現像スリーブ４ｂの長手方向の寸法に一致す
るように形成され、第２現像剤攪拌搬送部材３は、第１
現像剤攪拌搬送部材２よりも長手方向に長く形成されて
おり、いずれも現像スリーブ４ｂの回転方向と同方向に
回転可能に支持され、互いに現像剤を軸の逆方向に搬送
する。現像剤担持体４は、仕切り板５と対向する位置で
現像剤攪拌搬送部材２、３と平行に配設されている。ま
た、第２現像剤攪拌搬送部材３の下流側には、トナー濃
度検知センサ７が取り付けられている。(First Embodiment) An embodiment of the developing device according to the present invention, which is a developing device of the present invention used in the above image forming apparatus, will be described. FIG. 2 is a schematic configuration diagram of the developing device, and FIG. 3 is a cross-sectional view of the developing device shown in FIG. This developing device 9
The developer carrier 4 and the developer stirring / conveying means are accommodated in a housing having an opening, and the opening is opposed to the photoconductor 1. The developer carrier 4 has a plurality of magnets inside, and includes a fixedly supported magnet roller 4a, and a developing sleeve 4b formed on the peripheral surface thereof and supported rotatably in the direction of the arrow, It is arranged in the opening of the housing so as to be in close proximity to the photoconductor 1. A developing doctor 6 for charging the developer on the developing sleeve 4b is disposed near the developing sleeve 4b near the peripheral surface of the developer carrier 4 and upstream of a developing area where the developing sleeve 4b and the photoconductor 1 face each other. Have been. The developer stirring / conveying means includes a first developer stirring / conveying member 2 and a second developer stirring / conveying member 3 having a screw shape and arranged in parallel with a partition plate 5 therebetween. The first developer stirring and conveying member 2 is formed such that its length in the longitudinal direction matches the length in the longitudinal direction of the developing sleeve 4b.
It is formed longer in the longitudinal direction than the developer agitating and conveying member 2, and each is rotatably supported in the same direction as the rotation direction of the developing sleeve 4b, and conveys the developer in the direction opposite to the axis of each other. The developer carrier 4 is disposed in parallel with the developer stirring and conveying members 2 and 3 at a position facing the partition plate 5. Further, a toner concentration detection sensor 7 is attached downstream of the second developer stirring and conveying member 3.

【００２６】現像装置９内の現像剤は、２つの異なる現
像剤循環経路によって搬送される。第１の現像剤循環経
路は、図３に示す矢印Ｃ→Ｄ→Ｅ→Ｆ→Ｃに従う循環経
路である。矢印Ｃ及びＥの現像剤の搬送は、それぞれ第
２現像剤攪拌搬送部材３及び第１現像剤攪拌搬送部材２
の回転により行われる。また、矢印Ｄの現像剤の搬送
は、現像スリーブ４ｂの回転で第２現像剤攪拌搬送部材
３側から第１現像剤攪拌搬送部材２側へ現像剤を汲み上
げることにより行われ、矢印Ｆの搬送は重力落下であ
る。第２の現像剤循環経路では、現像剤を矢印Ｇのよう
に、第１現像剤攪拌搬送部材２側から、図２に示すよう
に第１現像剤攪拌搬送部材２と第２現像剤攪拌搬送部材
３とからほぼ等距離で、仕切り板５をまたぐ位置に配置
された現像剤担持体４の現像スリーブ４ｂ上に汲み上げ
ることにより成立する。The developer in the developing device 9 is transported by two different developer circulation paths. The first developer circulation path is a circulation path according to arrows C → D → E → F → C shown in FIG. The transport of the developer indicated by arrows C and E is performed by the second developer stirring transport member 3 and the first developer stirring transport member 2 respectively.
The rotation is performed. The transport of the developer indicated by the arrow D is performed by pumping the developer from the second developer stirring / conveying member 3 to the first developer stirring / conveying member 2 by the rotation of the developing sleeve 4b. Is gravity drop. In the second developer circulation path, the developer is conveyed from the first developer stirring and conveying member 2 side as shown by an arrow G to the first developer stirring and conveying member 2 as shown in FIG. This is achieved by pumping the developer onto the developing sleeve 4b of the developer carrier 4 disposed at a position that straddles the partition plate 5 at substantially the same distance from the member 3.

【００２７】現像スリーブ４ｂ上に汲み上げられた現像
剤は、現像スリーブ４ｂの回転により、現像ドクタ６の
位置を通過するときに現像剤の量が規制されると共にト
ナーが帯電され、現像領域に搬送される。現像領域で
は、静電潜像が形成された感光体１と、電気的バイアス
が印加された現像スリーブ４ｂとの間の電界によりトナ
ーが感光体１側へ移動し、感光体１の静電潜像を顕像化
する。現像領域を通過した現像剤は、仕切り板５の長手
方向の寸法に一致した寸法を有し、仕切り板５に取り付
けられた現像剤剥離部材８により、第２現像剤攪拌搬送
部材３の上方で現像スリーブ４ｂ表面から離れ、第２現
像剤攪拌搬送部材３側へ落下する。このように、現像剤
を現像スリーブ４ｂから放出する方法として、本実施形
態では仕切り板５に現像剤剥離部材８を取り付けること
により行ったが、これ以外の方法、例えば仕切り板と現
像スリーブとの間隔を狭くして現像剤を通過させないよ
うにする方法を用いることもできる。The amount of the developer pumped onto the developing sleeve 4b is regulated by the rotation of the developing sleeve 4b when passing the position of the developing doctor 6, the toner is charged, and the developer is conveyed to the developing area. Is done. In the developing area, the toner moves toward the photoconductor 1 due to an electric field between the photoconductor 1 on which the electrostatic latent image is formed and the developing sleeve 4 b to which an electric bias is applied, and the electrostatic latent image on the photoconductor 1 is moved. Visualize the image. The developer that has passed through the developing region has a size corresponding to the size of the partition plate 5 in the longitudinal direction, and is separated from the second developer stirring and conveying member 3 by the developer peeling member 8 attached to the partition plate 5. The developer leaves the surface of the developing sleeve 4b and drops toward the second developer stirring and conveying member 3. As described above, the method of discharging the developer from the developing sleeve 4b is performed by attaching the developer peeling member 8 to the partition plate 5 in the present embodiment. It is also possible to use a method of narrowing the interval so that the developer does not pass therethrough.

【００２８】このように、本実施形態の現像装置４は２
つの現像剤循環経路を有し、現像領域を通過した現像剤
が直接第１現像剤攪拌搬送部材２側に戻らないため、第
１現像剤攪拌搬送部材２上流側と下流側とでトナー濃度
差がなくなり、濃度差がなく濃度追従性の良い均一な画
像を得ることができる。また、現像領域へ搬送される現
像剤は、攪拌されて第１現像剤攪拌搬送部材２側から汲
み上げられ、現像ドクタ６を一回だけ通過してきた現像
剤であり、現像剤の帯電条件が等しく、現像剤の帯電量
のバラツキが小さい。したがって、トナーが均一に帯電
されているため、トナー飛散や地肌汚れがなく、画像の
細部でのバラツキのない良質な画像を得ることができ
る。As described above, the developing device 4 of the present embodiment
Since the developer passing through the developing area does not return directly to the first developer stirring and conveying member 2 side, the toner concentration difference between the upstream side and the downstream side of the first developer stirring and conveying member 2 is provided. Is eliminated, and a uniform image with no density difference and good density followability can be obtained. The developer conveyed to the developing area is agitated and pumped up from the first developer agitating / conveying member 2 side, and has passed through the developing doctor 6 only once. In addition, the variation in the charge amount of the developer is small. Therefore, since the toner is uniformly charged, it is possible to obtain a high-quality image free from toner scattering and background contamination, and from variations in image details.

【００２９】（第２の実施形態）請求項２に記載の現像
装置の一実施形態について説明する。図４は、この現像
装置内部の配置及び現像剤の循環方向を示す上面図であ
り、図５及び図６は、それぞれ図４中の１４ｌ及び１４
ｍにおける各部材の配置及び磁束密度分布を示す断面図
である。現像剤を現像剤攪拌搬送部材１２、１３の軸方
向に搬送し、第１現像剤攪拌搬送部材１２側から第２現
像剤攪拌搬送部材１３側へ受け渡す領域である１４ｍに
対応する領域における固定磁石の磁束密度分布を図５に
示す。この領域の現像装置１９内部に固定された磁石１
４ａは、第２現像剤攪拌搬送部材１３に面した領域で磁
気拘束力が弱いため、この領域で現像スリーブ１４ｂ上
に現像剤を保持できなくなる。このため、現像領域を通
過してきた現像剤は、仕切り板１５と現像スリーブ１４
ｂとの間を通過して第１現像剤攪拌搬送部材１２側へ運
ばれることなく第２現像剤攪拌搬送部材１３上に落下
し、矢印Ｃの下流側端部へ運ばれる。同時にこの領域で
は、固定磁石１４ａのＳ２極により第１現像剤攪拌搬送
部材１２側から現像剤が汲み上げられ、Ｎ２極、Ｓ１極
及びＮ１極により現像領域へ運ばれる。(Second Embodiment) An embodiment of the developing device according to claim 2 will be described. FIG. 4 is a top view showing the arrangement inside the developing device and the direction in which the developer circulates, and FIGS. 5 and 6 show 141 and 14 in FIG. 4, respectively.
It is sectional drawing which shows arrangement | positioning of each member in m and magnetic flux density distribution. The developer is conveyed in the axial direction of the developer stirring and conveying members 12 and 13, and is fixed in an area corresponding to 14 m, which is an area where the developer is conveyed from the first developer stirring and conveying member 12 to the second developer stirring and conveying member 13. FIG. 5 shows the magnetic flux density distribution of the magnet. Magnet 1 fixed inside developing device 19 in this region
In the area 4a, the magnetic binding force is weak in the area facing the second developer stirring and conveying member 13, so that the developer cannot be held on the developing sleeve 14b in this area. For this reason, the developer that has passed through the developing area is separated from the partition plate 15 and the developing sleeve 14.
b, falls on the second developer stirring and conveying member 13 without being conveyed to the first developer stirring and conveying member 12 side, and is conveyed to the downstream end of arrow C. At the same time, in this area, the developer is pumped up from the first developer stirring and conveying member 12 side by the S2 pole of the fixed magnet 14a, and is carried to the developing area by the N2 pole, the S1 pole, and the N1 pole.

【００３０】第２現像剤攪拌搬送部材１３から第１現像
剤攪拌搬送部材１２への現像剤受け渡し部である１４ｌ
の領域における磁束密度分布は、図６に示すとおりであ
る。この領域では、第２現像剤攪拌搬送部材１３側の現
像剤がＮ３により汲み上げられ、Ｓ２極と現像スリーブ
１４ｂの回転により第１現像剤攪拌搬送部材１２側へ搬
送される。搬送された現像剤は、Ｎ２極を経てＳ１極の
領域で現像ドクタ１６により現像剤量が規制されると共
にトナーが帯電される。この時、余分な現像剤は第１現
像剤攪拌搬送部材１２側へ落とされる。仕切り板１５
は、第２現像剤攪拌搬送部材の下流側は図４に示すよう
に現像装置の側面まで延長し、第２現像剤攪拌搬送部材
１３側から第１現像剤攪拌搬送部材１２側への現像剤受
け渡し部では、現像スリーブ１４ｂ上の現像剤の搬送を
妨げない程度に、現像スリーブ１４ｂとのギャップが設
定される。また、１４ｌの範囲には、図４及び図５に示
すように、第１現像剤攪拌搬送部材１２側へ搬送された
現像剤の第２現像剤攪拌搬送部材１３側への落下を防止
するための現像剤落下防止部材１８が仕切り板１５に具
備されている。現像剤落下防止部材１８は、マイラ等の
弾性部材によって形成し、現像スリーブ１４ｂのトレー
リングに当たるように仕切り板１５に取り付けられてい
る。A developer transfer portion 14l from the second developer stirring and conveying member 13 to the first developer stirring and conveying member 12
The magnetic flux density distribution in the region is as shown in FIG. In this area, the developer on the second developer stirring and conveying member 13 side is pumped up by N3, and is conveyed to the first developer stirring and conveying member 12 side by the rotation of the S2 pole and the developing sleeve 14b. The amount of the transported developer is regulated by the developing doctor 16 in the region of the S1 pole through the N2 pole, and the toner is charged. At this time, excess developer is dropped to the first developer stirring and conveying member 12 side. Partition plate 15
4, the downstream side of the second developer stirring and conveying member extends to the side of the developing device as shown in FIG. 4, and the developer from the second developer stirring and conveying member 13 side to the first developer stirring and conveying member 12 side. In the transfer section, a gap with the developing sleeve 14b is set so as not to hinder the transport of the developer on the developing sleeve 14b. Further, in the range of 14 l, as shown in FIGS. 4 and 5, in order to prevent the developer conveyed to the first developer stirring and conveying member 12 from dropping to the second developer stirring and conveying member 13 side. Is provided on the partition plate 15. The developer drop preventing member 18 is formed of an elastic member such as a mylar, and is attached to the partition plate 15 so as to hit the trailing of the developing sleeve 14b.

【００３１】この時、矢印Ｇ方向の現像剤搬送量Ｇ’
は、現像スリーブ１４ｂの現像ドクタ１６を通過後の現
像剤汲み上げ量と回転数、つまり現像条件によって規定
される。矢印Ｄ方向の現像剤搬送量Ｄ’は、図４に示す
現像スリーブ１４ｂの１４ｌの領域で第２現像剤攪拌搬
送部材１３側から第１現像剤攪拌搬送部材１２側へ汲み
上げられる現像剤の量であり、この現像剤量は図６に示
す固定磁石１４ａの磁力分布と図４に示す１４ｌの長さ
により規定される。また、現像剤搬送量Ｆ’は、現像装
置内の現像剤量により決定される。この現像装置におい
て現像剤の循環を円滑に行うためには、現像剤搬送量
Ｄ’＝現像剤搬送量Ｇ’＋現像剤搬送量Ｆ’とならなけ
ればならない。現像剤搬送量Ｄ’＜現像剤搬送量Ｇ’＋
現像剤搬送量Ｆ’となった場合には、第２現像剤攪拌搬
送部材１３側で現像剤量が増え続け、第２現像剤攪拌搬
送部材１３側で現像剤詰まりが生じてしまう。現像剤詰
まりが発生しないようにするためには、現像条件と現像
剤量を決定した後、現像剤搬送量Ｄ’＝現像剤搬送量
Ｇ’＋現像剤搬送量Ｆ’の関係が成立するように図６の
固定磁石１４ａの磁力分布と、１４ｌの長さを設定す
る。また、現像剤搬送量Ｇ’＋現像剤搬送量Ｆ’を搬送
できるように、第２現像剤攪拌搬送部材１３のスクリュ
ー径、スクリューピッチ及びスクリュー回転数を設定す
る。また、図５の現像スリーブ１４ｂと仕切り板１５と
の間にギャップを設け、現像剤搬送量Ｄ’＜現像剤搬送
量Ｇ’＋現像剤搬送量Ｆ’となった場合、第２現像剤攪
拌搬送部材１３側で増量した現像剤をギャップを通して
矢印Ｈのように第１現像剤攪拌搬送部材１２側へオーバ
ーフローさせ、第２現像剤攪拌搬送部材１３側での現像
剤詰まりを防止する。At this time, the developer conveyance amount G 'in the direction of arrow G
Is determined by the developer pumping amount and the rotation speed of the developing sleeve 14b after passing through the developing doctor 16, that is, the developing conditions. The amount D ′ of developer transported in the direction of arrow D is the amount of developer pumped from the side of the second developer agitating and transporting member 13 to the side of the first developer agitating and transporting member 12 in the area 14l of the developing sleeve 14b shown in FIG. This developer amount is defined by the magnetic force distribution of the fixed magnet 14a shown in FIG. 6 and the length of 141 shown in FIG. Further, the developer transport amount F ′ is determined by the developer amount in the developing device. In order to smoothly circulate the developer in this developing device, the developer transport amount D ′ must be equal to the developer transport amount G ′ + the developer transport amount F ′. Developer transport amount D ′ <Developer transport amount G ′ +
When the developer transport amount F ′ is reached, the developer amount continues to increase on the second developer agitating and transporting member 13 side, and the developer is clogged on the second developer agitating and transporting member 13 side. In order to prevent the developer from being clogged, after determining the developing condition and the amount of the developer, the relationship of the developer transport amount D ′ = the developer transport amount G ′ + the developer transport amount F ′ is established. In FIG. 6, the magnetic force distribution of the fixed magnet 14a and the length of 141 are set. Further, the screw diameter, screw pitch, and screw rotation speed of the second developer stirring and conveying member 13 are set so that the amount of developer conveyance G ′ + the amount of developer conveyance F ′ can be conveyed. In addition, when a gap is provided between the developing sleeve 14b and the partition plate 15 in FIG. 5 and the developer transport amount D ′ <the developer transport amount G ′ + the developer transport amount F ′, the second developer stirring is performed. The increased amount of the developer on the side of the conveying member 13 is caused to overflow to the first developer stirring and conveying member 12 through the gap as shown by the arrow H, thereby preventing the second developer stirring and conveying member 13 from being clogged.

【００３２】以上のように、この現像装置では、現像剤
を第２現像剤攪拌搬送部材側から第１現像剤攪拌搬送部
材側へ受け渡す領域での現像剤の移動を促すことによっ
て、第２現像剤攪拌搬送部材−現像剤受け渡し部−第１
現像剤攪拌搬送部材−現像剤受け渡し部−第２現像剤攪
拌搬送部材のように現像剤を循環させる循環経路と、上
記以外の領域で、現像領域を通過した現像スリーブ上の
現像剤を第２現像剤攪拌搬送部材上に落下させる経路の
２つの現像剤循環経路を形成し、これにより、現像スリ
ーブ上のトナー濃度を均一にすると共に、第２現像剤攪
拌搬送部材上での現像剤詰まりを防止し、良好な現像を
行うことができる。As described above, in this developing device, the movement of the developer in the area where the developer is transferred from the side of the second developer agitating and conveying member to the side of the first developer agitating and conveying member is promoted, whereby the second developer is moved. Developer stirring / conveying member-developer transfer section-first
A circulation path for circulating the developer like a developer stirring / conveying member-developer transfer section / second developer stirring / conveying member; Two developer circulation paths, which are paths for dropping onto the developer stirring and conveying member, are formed, whereby the toner concentration on the developing sleeve is made uniform, and the developer clogging on the second developer stirring and conveying member is prevented. Prevention and good development can be performed.

【００３３】（第３の実施形態）請求項３に記載の現像
装置の一実施形態について説明する。図７は、この現像
装置内部の配置及び現像剤の循環方向を示す上面図であ
り、図８は、図７中の２４ｌにおける各部材の配置及び
磁束密度分布を示す断面図である。この現像装置２９の
図７に示す領域２４ｍでは、仕切り板２５の先端が、図
８のように固定磁石２４ａの反発磁極部（Ｓ２極−Ｓ３
極間）より現像スリーブ２４ｂの回転方向下流に位置す
る。これにより、現像スリーブ２４ｂの反発磁極部で現
像スリーブ２４ｂから離れた現像剤は、仕切り板２５に
よって妨げられることなく、すべて第２現像剤攪拌搬送
部材２３側へ落下する。したがって、２４ｍの範囲で
は、現像領域を通過した現像剤が仕切り板２５と現像ス
リーブ２４ｂとの間を通過して第１現像剤攪拌搬送部材
２２側へ運ばれることはない。また、この範囲では、Ｓ
２極で第２現像剤攪拌搬送部材２２側から現像剤を汲み
上げ、Ｎ２、Ｓ１及びＮ１極により現像領域へ搬送す
る。第２現像剤攪拌搬送部材２３側へ落とされた現像剤
は、矢印Ｃの下流側端部へ運ばれる。(Third Embodiment) An embodiment of the developing device according to claim 3 will be described. FIG. 7 is a top view showing the arrangement inside the developing device and the direction of circulation of the developer, and FIG. 8 is a sectional view showing the arrangement of each member and the magnetic flux density distribution at 24l in FIG. In the region 24m of the developing device 29 shown in FIG. 7, the leading end of the partition plate 25 is connected to the repulsive magnetic pole portion (S2-pole-S3) of the fixed magnet 24a as shown in FIG.
(Between the gaps), and is located downstream of the developing sleeve 24b in the rotation direction. As a result, all the developer separated from the developing sleeve 24b at the repulsive magnetic pole portion of the developing sleeve 24b falls to the second developer stirring and conveying member 23 without being hindered by the partition plate 25. Therefore, within the range of 24 m, the developer that has passed through the developing area does not pass between the partition plate 25 and the developing sleeve 24b and is not carried to the first developer stirring and conveying member 22 side. In this range, S
The developer is pumped up from the second developer stirring and conveying member 22 side by two poles, and is conveyed to the developing area by the N2, S1, and N1 poles. The developer dropped to the second developer stirring and conveying member 23 is conveyed to the downstream end of arrow C.

【００３４】また、２４ｌの領域では、図８中の斜線部
で示したように、仕切り板２５の先端をカットし、この
端部にカット部の幅と等しい幅（２４ｌ）を有する現像
剤誘導部材２８が当接されている。この現像剤誘導部材
２８は、マイラ等の弾性材料から形成され、先端が現像
スリーブ２４ｂとの接触点より突き出すように現像スリ
ーブ２４ｂに当接されているため、現像剤誘導部材２８
により現像スリーブ２４ｂ上の現像剤が掻き落とされる
ことはない。これにより、２４ｌの領域で現像スリーブ
２４ｂから離れた現像剤は、現像剤誘導部材２８上に落
ち、第１現像剤攪拌搬送部材２２側へ戻される。In the region of 24 l, as shown by the hatched portion in FIG. 8, the leading end of the partition plate 25 is cut, and a developer guide having a width (24 l) equal to the width of the cut portion at this end. The member 28 is in contact. The developer guiding member 28 is formed of an elastic material such as Mylar, and its tip is in contact with the developing sleeve 24b so as to protrude from a contact point with the developing sleeve 24b.
As a result, the developer on the developing sleeve 24b is not scraped off. As a result, the developer separated from the developing sleeve 24b in the area of 24l falls on the developer guide member 28 and returns to the first developer stirring and conveying member 22 side.

【００３５】したがって、この現像装置によれば、第２
現像剤攪拌搬送部材２３側から第１現像剤攪拌搬送部材
２２側へ現像剤を受け渡す領域に誘導部材を配置するこ
とにより、第２現像剤攪拌部材２３側から第１現像剤攪
拌搬送部材２２側への現像剤の受け渡しを促し、これ以
外の領域では、仕切り板２５の先端を固定磁石２４ａの
反発磁極部より現像スリーブ２４ｂの回転方向下流に位
置させることにより、現像領域を通過した現像剤をすべ
て第２現像剤攪拌搬送部材２３側へ落下させる。これに
より、現像スリーブ上のトナー濃度を均一化し、濃度ム
ラのない均一な画像を形成すると共に、第２現像剤攪拌
搬送部材での現像剤詰まりを防止し、均一に帯電させた
トナーによる良好な画像形成を行うことが可能となる。Therefore, according to this developing device, the second
By arranging the guide member in an area where the developer is transferred from the developer stirring and conveying member 23 to the first developer stirring and conveying member 22, the first developer stirring and conveying member 22 is moved from the second developer stirring member 23 to the first developer stirring and conveying member 22. In the other region, the tip of the partition plate 25 is positioned downstream of the repulsion magnetic pole portion of the fixed magnet 24a in the rotation direction of the developing sleeve 24b, so that the developer passing through the developing region is Are all dropped to the second developer stirring and conveying member 23 side. As a result, the toner density on the developing sleeve is made uniform, a uniform image with no density unevenness is formed, the developer is prevented from being clogged by the second developer stirring and conveying member, and good toner is uniformly charged. Image formation can be performed.

【００３６】（第４の実施形態）請求項４に記載の現像
装置の一実施形態について説明する。図９は、この現像
装置内部の配置及び現像剤の循環方向を示す上面図であ
り、図１０は、図９中の３４ｌにおける各部材の配置を
示す断面図である。この現像装置３９は、第２現像剤攪
拌搬送部材３３側から第１現像剤攪拌搬送部材３２側へ
現像剤を受け渡す領域（領域３４ｌ）の第２現像剤攪拌
搬送部材３３及び第１現像剤攪拌搬送部材３２の端部
に、第２現像剤攪拌搬送部材３３側の現像剤を第１現像
剤攪拌搬送部材３２側へ搬送する現像剤搬送部材４０が
設けられている。現像剤搬送部材４０は、複数の突起部
４０ａを有するキャタピラ（登録商標）形状から成り、
第２現像剤攪拌搬送部材３３の中心軸と第１現像剤攪拌
搬送部材３２の中心軸とを取り巻くように取り付けられ
ており、第１現像剤攪拌搬送部材３２又は第２現像剤攪
拌搬送部材３３の駆動を受けて回転し、もう一方の現像
剤攪拌搬送部材に駆動を伝達する。この現像装置３９の
仕切り板３５の現像剤搬送部材４０側の端部は、現像装
置３９の内側面まで延長されているが、現像剤搬送部材
４０と交叉する部分には図１０に示すような切り欠きを
有し、これにより、現像剤搬送部材４０が仕切り板３５
の切り欠き部を通過して回転することができるように構
成されている。また、現像剤搬送部材４０は、各突起部
４０ａ間に貫通穴４０ｂを備え、現像剤はこの突起部４
０ａによって汲み上げられ、第２現像剤攪拌搬送部材３
３側から第１現像剤攪拌搬送部材３２側へ搬送される。
そして、現像剤は第１現像剤攪拌搬送部材３２の上方付
近まで搬送されて、突起部４０ａの間の貫通穴４０ｂか
ら仕切り板３５上へ落下し、第１現像剤攪拌搬送部材３
２へ取り込まれる。(Fourth Embodiment) An embodiment of the developing device according to the fourth aspect will be described. FIG. 9 is a top view showing the arrangement inside the developing device and the direction of circulation of the developer, and FIG. 10 is a cross-sectional view showing the arrangement of each member at 34l in FIG. The developing device 39 includes the second developer stirring and conveying member 33 and the first developer in an area (area 341) for transferring the developer from the second developer stirring and conveying member 33 to the first developer stirring and conveying member 32. At an end of the stirring and conveying member 32, a developer conveying member 40 for conveying the developer on the second developer stirring and conveying member 33 side to the first developer stirring and conveying member 32 side is provided. The developer transport member 40 has a caterpillar (registered trademark) shape having a plurality of protrusions 40a,
It is attached so as to surround the central axis of the second developer stirring / conveying member 33 and the central axis of the first developer stirring / conveying member 32, and is provided with the first developer stirring / conveying member 32 or the second developer stirring / conveying member 33. Rotates in response to the drive, and transmits the drive to the other developer stirring and conveying member. An end of the partition plate 35 of the developing device 39 on the side of the developer conveying member 40 is extended to the inner side surface of the developing device 39, and a portion intersecting with the developer conveying member 40 as shown in FIG. The developer conveying member 40 is provided with a notch so that the partition plate 35
It is configured to be able to rotate by passing through the notch portion of. Further, the developer conveying member 40 includes a through hole 40b between each of the protrusions 40a, and the developer is supplied to the protrusions 4a.
0a, the second developer stirring and conveying member 3
The developer is conveyed from the third side to the first developer stirring and conveying member 32 side.
Then, the developer is conveyed to a position near the upper portion of the first developer stirring and conveying member 32 and falls from the through hole 40b between the protrusions 40a onto the partition plate 35, and the first developer stirring and conveying member 3
2

【００３７】この時、矢印Ｇの現像剤搬送量Ｇ’は、現
像スリーブ３４ｂの現像ドクタ３６を通過した後の汲み
上げ量と回転数、すなわち現像条件によって決定され
る。また、矢印Ｄの現像剤搬送量Ｄ’は、現像剤搬送部
材４０による第２現像剤攪拌搬送部材３３側から第１現
像剤攪拌搬送部材３２側への現像剤汲み上げ量であり、
この量は、現像剤搬送部材４０を駆動する第１現像剤攪
拌搬送部材３２又は第２現像剤攪拌搬送部材３３の回転
数と現像剤搬送部材４０の形状により決定される。矢印
Ｆの現像剤搬送量Ｆ’は、この現像装置内の現像剤量に
より規定される。このような現像装置において現像剤循
環を円滑にし、良好な現像を行うためには、現像剤搬送
量Ｄ’＝現像剤搬送量Ｇ’＋現像剤搬送量Ｆ’の関係が
維持されることが望ましいが、現像剤搬送量Ｄ’＜現像
剤搬送量Ｇ’＋現像剤搬送量Ｆ’のような変動が生じた
場合は、第２現像剤攪拌搬送部材３３側で現像剤量が増
加し、第２現像剤攪拌搬送部材３３側で現像剤詰まりが
発生する。そこで、このような現像剤詰まりの発生を防
止するためには、現像条件を決定した後、現像剤搬送量
Ｄ’＝現像剤搬送量Ｇ’＋現像剤搬送量Ｆ’の関係が成
立するように、現像剤搬送部材４０の形状と、第２現像
剤攪拌搬送部材３３のスクリュー径、スクリューピッチ
及びスクリューの回転数を設定する。さらに、図１０の
現像スリーブ３４ｂと仕切り板３５との間にギャップを
設け、現像剤搬送量Ｄ’＜現像剤搬送量Ｇ’＋現像剤搬
送量Ｆ’となった場合に、第２現像剤攪拌搬送部材３３
側に増量した現像剤をギャップを通して第１現像剤攪拌
搬送部材３２側へ矢印Ｈのようにオーバーフローさせ、
これにより第２現像剤攪拌搬送部材３３側での現像剤詰
まりを防止する。At this time, the developer transfer amount G 'indicated by the arrow G is determined by the pumping amount and the rotation speed of the developing sleeve 34b after passing through the developing doctor 36, that is, the developing conditions. Further, a developer transport amount D ′ indicated by an arrow D is an amount of developer pumped up by the developer transport member 40 from the second developer agitating and transporting member 33 side to the first developer agitating and transporting member 32 side,
This amount is determined by the rotation speed of the first developer stirring and conveying member 32 or the second developer stirring and conveying member 33 for driving the developer conveying member 40 and the shape of the developer conveying member 40. The developer transport amount F ′ indicated by an arrow F is defined by the developer amount in the developing device. In such a developing device, in order to make the developer circulation smooth and perform good development, the relationship of developer transport amount D ′ = developer transport amount G ′ + developer transport amount F ′ must be maintained. Desirably, when a variation such as the developer transport amount D ′ <the developer transport amount G ′ + the developer transport amount F ′ occurs, the developer amount increases on the second developer stirring transport member 33 side, Developer clogging occurs on the side of the second developer stirring and conveying member 33. Therefore, in order to prevent the occurrence of such developer clogging, after the developing conditions are determined, the relationship of developer transport amount D ′ = developer transport amount G ′ + developer transport amount F ′ is established. Next, the shape of the developer conveying member 40, the screw diameter of the second developer stirring and conveying member 33, the screw pitch, and the number of rotations of the screw are set. Further, a gap is provided between the developing sleeve 34b and the partition plate 35 in FIG. 10, and when the developer transport amount D ′ <the developer transport amount G ′ + the developer transport amount F ′, the second developer Stir and transport member 33
The amount of the developer increased to the first side is caused to overflow through the gap toward the first developer stirring and conveying member 32 as shown by the arrow H,
This prevents the developer from being clogged on the side of the second developer stirring and conveying member 33.

【００３８】以上のように、この現像装置では、第２現
像剤攪拌搬送部材から第１現像剤攪拌搬送部材への現像
剤受け渡し部に搬送部材を設けることにより、第２現像
剤攪拌搬送部材側から第１現像剤攪拌搬送部材側への現
像剤の搬送を円滑に行うことができる。また、現像剤担
持体内部の固定磁石の磁束密度分布を上記のように設定
することにより、現像領域通過後の現像剤を現像スリー
ブから第２現像剤攪拌搬送部材上へ落下させる。このよ
うに、２つの現像剤循環経路を形成することにより、第
１現像剤攪拌搬送部材上のトナー濃度及び現像スリーブ
上のトナー濃度を均一化し、濃度ムラのない均一な画像
を形成すると共に、第２現像剤攪拌搬送部材上に増量し
た現像剤を第１現像剤攪拌搬送部材側へオーバーフロー
させ、第２現像剤攪拌搬送部材側での現像剤詰まりを防
止することができる。As described above, in this developing device, the transfer member is provided at the developer transfer portion from the second developer stirring and conveying member to the first developer stirring and conveying member, so that the second developer stirring and conveying member side is provided. The developer can be smoothly transported from the first developer agitating and transporting member side. Further, by setting the magnetic flux density distribution of the fixed magnet inside the developer carrier as described above, the developer after passing through the developing area is dropped from the developing sleeve onto the second developer stirring and conveying member. As described above, by forming the two developer circulation paths, the toner concentration on the first developer stirring and conveying member and the toner concentration on the developing sleeve are made uniform, and a uniform image without density unevenness is formed. The increased amount of the developer on the second developer stirring and conveying member overflows toward the first developer stirring and conveying member, thereby preventing the developer from being clogged on the second developer stirring and conveying member.

【００３９】[0039]

【発明の効果】以上説明したように、本発明の現像装置
では、現像領域を通過した現像剤がすべて第２現像剤攪
拌搬送部材側に戻されるため、第１現像剤攪拌搬送部材
側の現像剤は、すべて現像に使用されていないリフレッ
シュ（初期化）状態であり、トナー濃度が低下していな
い。したがって、第１現像剤攪拌搬送部材側のトナー濃
度は、上流側から下流側にかけて常に一定であり、現像
スリーブ上のトナー濃度に差がなくなるため、濃度差が
なく濃度追従性の良い均一な画像を得ることができる。
また、現像領域へ搬送される現像剤は、充分に攪拌され
て第１現像剤攪拌搬送部材側から汲み上げられ、現像ド
クタと対向する領域を一回だけ通過してきた現像剤であ
るため、帯電条件が等しく、帯電量のバラツキが小さく
なる。したがって、トナーが均一に帯電されているた
め、トナー飛散や地肌汚れがなく細部の画像バラツキの
ない良質な画像を形成することができる。As described above, in the developing device of the present invention, since all the developer that has passed through the developing area is returned to the second developer stirring and conveying member side, the developing agent on the first developer stirring and conveying member side is developed. All of the agents are in a refreshed (initialized) state not used for development, and the toner concentration is not reduced. Therefore, the toner concentration on the first developer stirring and conveying member side is always constant from the upstream side to the downstream side, and there is no difference in the toner concentration on the developing sleeve. Can be obtained.
Further, since the developer conveyed to the developing area is sufficiently stirred and pumped up from the first developer stirring and conveying member side, and has passed only once through the area facing the developing doctor, the charging condition And the variation of the charge amount is small. Accordingly, since the toner is uniformly charged, it is possible to form a high-quality image free from toner scattering and background contamination and without image variations in detail.

【００４０】また、前記現像剤担持体の固定磁石を、第
２現像剤攪拌搬送部材側から第１現像剤攪拌搬送部材側
へ現像剤を受け渡す領域に対向する領域に、前記第１現
像剤攪拌搬送部材へ現像剤を汲み上げる磁気拘束力を有
し、その他の領域では、現像剤を保持しないように配置
することにより、現像剤を第１現像剤攪拌搬送部材と第
２現像剤攪拌搬送部材との間で循環させる経路及び現像
領域通過後の現像剤を現像スリーブから第２現像剤攪拌
搬送部材側へ直接落下させる経路の２つの経路を成立さ
せ、これにより、第１現像剤攪拌搬送部材上のトナー濃
度並びに現像スリーブ上のトナー濃度を均一化し、濃度
ムラのない均一な画像を形成することができる。また、
第２現像剤攪拌搬送部材上に増量した現像剤を第１現像
剤攪拌搬送部材側へオーバーフローさせ、第２現像剤攪
拌搬送部材側での現像剤詰まりを防止することができ
る。The fixed magnet of the developer carrying member is provided in a region opposed to a region for transferring the developer from the side of the second developer stirring and conveying member to the side of the first developer stirring and conveying member. It has a magnetic binding force for pumping up the developer to the stirring / conveying member, and is arranged so as not to hold the developer in the other areas, so that the developer is moved between the first developer stirring / conveying member and the second developer stirring / conveying member. And a path for directly dropping the developer after passing through the developing area from the developing sleeve to the second developer stirring and conveying member side, thereby establishing a first developer stirring and conveying member. The above toner concentration and the toner concentration on the developing sleeve can be made uniform, and a uniform image without density unevenness can be formed. Also,
The increased amount of the developer on the second developer stirring and conveying member overflows toward the first developer stirring and conveying member, thereby preventing the developer from being clogged on the second developer stirring and conveying member.

【００４１】さらに、第２現像剤攪拌搬送部材から第１
現像剤攪拌搬送部材への現像剤受け渡し部に現像剤誘導
部材を設けることにより、第２現像剤攪拌搬送部材側か
ら第１現像剤攪拌搬送部材側への現像剤の搬送を確実に
行う。また、現像剤担持体内部の固定磁石の磁束密度分
布を上記のように設定することにより、現像領域通過後
の現像剤を現像スリーブから第２攪拌搬送部材上へ落下
させる。これにより、２つの現像剤循環経路が形成さ
れ、第１現像剤攪拌搬送部材上のトナー濃度及び現像ス
リーブ上のトナー濃度を均一化し、濃度ムラのない均一
な画像を形成すると共に、第２現像剤攪拌搬送部材上に
増量した現像剤を第１現像剤攪拌搬送部材側へオーバー
フローさせ、第２現像剤攪拌搬送部材側での現像剤詰ま
りを防止することができる。Further, the first developer agitating and conveying member
By providing the developer guiding member at the developer transfer portion to the developer stirring and conveying member, the developer is reliably conveyed from the second developer stirring and conveying member to the first developer stirring and conveying member. Also, by setting the magnetic flux density distribution of the fixed magnet inside the developer carrier as described above, the developer after passing through the developing area is dropped from the developing sleeve onto the second stirring and conveying member. As a result, two developer circulation paths are formed, the toner density on the first developer stirring and conveying member and the toner density on the developing sleeve are made uniform, and a uniform image without density unevenness is formed. The increased amount of the developer on the developer agitating / conveying member overflows to the first developer agitating / conveying member side, thereby preventing the developer from being clogged on the second developer agitating / conveying member side.

【００４２】さらに、第２現像剤攪拌搬送部材から第１
現像剤攪拌搬送部材への現像剤受け渡し部に搬送部材を
設けることにより、第２現像剤攪拌搬送部材側から第１
現像剤攪拌搬送部材側への現像剤の搬送を円滑に行うこ
とができる。また、これ以外の領域では、現像剤担持体
内部の固定磁石の磁束密度分布を上記のように設定する
ことにより、現像領域通過後の現像剤を現像スリーブか
ら第２現像剤攪拌搬送部材上へ落下させる。このよう
に、２つの現像剤循環経路を形成することにより、第１
現像剤攪拌搬送部材上のトナー濃度及び現像スリーブ上
のトナー濃度を均一化し、濃度ムラのない均一な画像を
形成すると共に、第２現像剤攪拌搬送部材上に増量した
現像剤を第１現像剤攪拌搬送部材側へオーバーフローさ
せ、第２現像剤攪拌搬送部材側での現像剤詰まりを防止
することができる。Further, the first developer agitating and conveying member
By providing a transport member at a developer transfer portion to the developer agitating / transporting member, the first developer agitating / transporting member side can receive the first
The developer can be smoothly transported to the developer stirring and transporting member. In the other area, by setting the magnetic flux density distribution of the fixed magnet inside the developer carrier as described above, the developer after passing the developing area is transferred from the developing sleeve to the second developer stirring and conveying member. Let it fall. Thus, by forming two developer circulation paths, the first
The toner concentration on the developer stirring and conveying member and the toner concentration on the developing sleeve are made uniform to form a uniform image without density unevenness, and the increased amount of the developer is transferred onto the second developer stirring and conveying member by the first developer. It is possible to prevent the developer from being clogged on the side of the second developer stirring and conveying member by overflowing to the stirring and conveying member side.

【００４３】また、上記のような現像装置を有する画像
形成装置を用いることにより、トナー飛散や地肌汚れが
なく、細部のバラツキのない画像を均一な濃度で安定し
て得ることが可能となる。Further, by using the image forming apparatus having the developing device as described above, it is possible to stably obtain an image with no unevenness in detail without toner scattering or background contamination.

【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形態が用いられ
る複写機を示す概略構成図である。FIG. 1 is a schematic configuration diagram illustrating a copying machine in which an embodiment of an image forming apparatus according to the present invention is used.

【図２】請求項１に記載の現像装置を示す概略構成図で
ある。FIG. 2 is a schematic configuration diagram showing a developing device according to the first embodiment.

【図３】図２に示す現像装置のＳ−Ｓにおける断面図で
ある。FIG. 3 is a cross-sectional view of the developing device shown in FIG. 2 taken along line S-S.

【図４】請求項２に記載の現像装置の一実施形態を示す
上面図である。FIG. 4 is a top view showing an embodiment of the developing device according to claim 2;

【図５】図４中の１４ｌにおける各部材の配置及び磁束
密度分布を示す断面図である。FIG. 5 is a sectional view showing the arrangement of each member and the magnetic flux density distribution at 14l in FIG. 4;

【図６】図４中の１４ｍにおける各部材の配置及び磁束
密度分布を示す断面図である。6 is a cross-sectional view showing the arrangement of each member and the magnetic flux density distribution at 14m in FIG.

【図７】請求項３に記載の現像装置の一実施形態を示す
上面図である。FIG. 7 is a top view showing an embodiment of the developing device according to claim 3;

【図８】図７中の２４ｌにおける各部材の配置及び磁束
密度分布を示す断面図である。8 is a cross-sectional view showing the arrangement of each member and the magnetic flux density distribution at 24l in FIG.

【図９】請求項４に記載の現像装置の一実施形態を示す
上面図である。FIG. 9 is a top view showing an embodiment of the developing device according to claim 4;

【図１０】図９中の３４ｌにおける各部材の配置を示す
断面図である。FIG. 10 is a cross-sectional view showing an arrangement of each member at 34l in FIG.

【図１１】従来の現像装置を示す概略構成図である。FIG. 11 is a schematic configuration diagram showing a conventional developing device.

【図１２】図１１に示す現像装置の上面図である。12 is a top view of the developing device shown in FIG.

【符号の説明】[Explanation of symbols]

１、１１、２１、３１、８１ 感光体 ２、１２、２２、３２、５２ 第１現像剤攪拌搬送部材 ３、１３、２３、３３、５３ 第２現像剤攪拌搬送部材 ４、１４、２４、３４、５４、８４ 現像剤担持体 ４ａ、１４ａ、２４ａ、３４ａ、５４ａ 固定磁石 ４ｂ、１４ｂ、２４ｂ、３４ｂ、５４ｂ 現像スリーブ ５、１５、２５、３５、５５ 仕切り板 ６、１６、２６、３６、５６、８６ 現像ドクタ ７、１７、２７、３７、５７ トナー濃度検知センサ ８ 現像剤剥離部材 ９、１９、２９、３９、５９、８９ 現像装置 １８ 現像剤落下防止部材 ２８ 現像剤誘導部材 ６０ 画像読み取り装置 ６１ 排風装置 ７０ 画像書込装置 ７１ レーザ駆動装置 ７２ 反射鏡 ７３ レーザビーム ８０ 画像形成装置 ８２ 除電ランプ ８３ 帯電手段 ８５ 転写手段 ８７ 定着手段 ８７ａ 加熱ローラ ８７ｂ 加圧ローラ ８８ 排紙トレイ部 ９０ 給紙装置 ９１ 給紙カセット ９２ 給紙ローラ ９３ 反転用カセット ９４ 反転用給紙ローラ ９５ 紙搬送ローラ ９６ レジストローラ Ａ トナー補給経路 Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈ 現像剤循環経路 1, 11, 21, 31, 81 Photoconductor 2, 12, 22, 32, 52 First developer stirring and conveying member 3, 13, 23, 33, 53 Second developer stirring and conveying member 4, 14, 24, 34 , 54, 84 Developer carrier 4a, 14a, 24a, 34a, 54a Fixed magnet 4b, 14b, 24b, 34b, 54b Developing sleeve 5, 15, 25, 35, 55 Partition plate 6, 16, 26, 36, 56 , 86 developing doctor 7, 17, 27, 37, 57 toner density detecting sensor 8 developer peeling member 9, 19, 29, 39, 59, 89 developing device 18 developer falling prevention member 28 developer guiding member 60 image reading device 61 exhaust device 70 image writing device 71 laser driving device 72 reflecting mirror 73 laser beam 80 image forming device 82 static elimination lamp 83 charging means 85 transfer means 87 constant Means 87a Heating roller 87b Pressure roller 88 Discharge tray unit 90 Paper supply device 91 Paper supply cassette 92 Paper supply roller 93 Reversing cassette 94 Reversing paper supply roller 95 Paper transport roller 96 Registration roller A Toner supply paths C, D, E, F, G, H Developer circulation path

Claims (8)

【特許請求の範囲】[Claims] 【請求項１】 トナーとキャリアとから成る二成分現像
剤を仕切り板を挟んで互いに逆の方向に攪拌搬送する第
１現像剤攪拌搬送部材と第２現像剤攪拌搬送部材とから
成る現像剤攪拌搬送手段と、該現像剤攪拌搬送手段と平
行に配設され、内部に固定された磁石と、周面上に回転
可能に支持された現像スリーブとを備え、表面に前記二
成分現像剤を担持する現像剤担持体とを有し、像担持体
上の静電潜像を可視化する現像装置において、 前記現像剤攪拌搬送手段は、前記第１現像剤攪拌搬送部
材と前記第２現像剤攪拌搬送部材との中間部で前記現像
剤担持体と対向し、前記第１現像剤攪拌搬送部材が、前
記第２現像剤攪拌搬送部材に対して前記現像スリーブの
回転の下流側に位置するように回転可能に支持され、 前記磁石は、前記第１現像剤攪拌搬送部材から現像剤を
汲み上げると共に、前記像担持体と対向する現像領域を
通過した現像剤を前記第２現像剤攪拌搬送部材上に落下
させる磁気拘束力を有することを特徴とする現像装置。1. A developer agitator comprising a first developer agitator / conveyer member and a second developer agitator / conveyer member for agitating and transporting a two-component developer comprising a toner and a carrier in directions opposite to each other across a partition plate. Transport means, a magnet fixed inside, and a developing sleeve rotatably supported on the peripheral surface, which is provided in parallel with the developer stirring and transporting means, and carries the two-component developer on the surface. A developer carrying member for visualizing an electrostatic latent image on the image carrying member, wherein the developer stirring / conveying means comprises the first developer stirring / conveying member and the second developer stirring / conveying member. The first developer stirring and conveying member is opposed to the developer carrier at an intermediate portion between the members, and is rotated such that the first developer stirring and conveying member is positioned downstream of the rotation of the developing sleeve with respect to the second developer stirring and conveying member. And the magnet is provided with the first developer.拌搬 with the feed member pumping a developer, developing apparatus is characterized by having a magnetic binding force for dropping the developer having passed through the image bearing member opposed to the developing region to the second developer stirring and conveying member. 【請求項２】 前記第２現像剤攪拌搬送部材から前記第
１現像剤攪拌搬送部材へ現像剤を受け渡す領域を領域
Ｌ、前記現像剤攪拌搬送部材の軸方向へ現像剤を搬送
し、第１現像剤攪拌搬送部材から第２現像剤攪拌搬送部
材へ現像剤を受け渡す領域を領域Ｍとするとき、 前記磁石は、前記領域Ｌに対向する領域に、現像剤を前
記第２現像剤攪拌搬送部材から前記現像スリーブに汲み
上げた後、前記第１現像剤攪拌搬送部材へ受け渡す磁気
拘束力を有し、前記領域Ｍに対向する領域では、現像剤
を保持しないように配置されていることを特徴とする請
求項１に記載の現像装置。2. An area L for transferring the developer from the second developer stirring and conveying member to the first developer stirring and conveying member, and the developer is conveyed in the axial direction of the developer stirring and conveying member. When a region where the developer is transferred from the first developer stirring and conveying member to the second developer stirring and conveying member is defined as a region M, the magnet moves the developer to the second developer stirring and conveying member in a region opposed to the region L. After being pumped from the transfer member to the developing sleeve, it has a magnetic binding force to be transferred to the first developer stirring and transfer member, and is arranged so as not to hold the developer in a region facing the region M. The developing device according to claim 1, wherein: 【請求項３】 前記領域Ｌに前記現像スリーブから離脱
した現像剤を前記第１現像剤攪拌搬送部材へ誘導する誘
導部材を備えたことを特徴とする請求項１又は請求項２
に記載の現像装置。3. The device according to claim 1, further comprising a guide member for guiding the developer detached from the developing sleeve to the first developer stirring and conveying member in the region L.
3. The developing device according to claim 1. 【請求項４】 前記第２現像剤攪拌搬送部材から前記第
１現像剤攪拌搬送部材へ現像剤を受け渡す領域に、現像
剤搬送部材を備えたことを特徴とする請求項１に記載の
現像装置。4. The developing device according to claim 1, wherein a developer conveying member is provided in a region for transferring the developer from the second developer stirring and conveying member to the first developer stirring and conveying member. apparatus. 【請求項５】 表面に静電潜像を形成する感光体と、該
感光体の表面を一様に帯電する帯電手段と、該感光体の
表面に露光する露光手段と、トナーとキャリアとから成
る二成分現像剤によって前記静電潜像を現像し、トナー
像を形成する現像装置と、該トナー像を記録媒体上に転
写する転写装置と、前記記録媒体上に転写されたトナー
像を定着する定着装置と有する画像形成装置において、 前記現像装置は、トナーとキャリアとから成る二成分現
像剤を仕切り板を挟んで互いに逆の方向に攪拌搬送する
第１現像剤攪拌搬送部材と第２現像剤攪拌搬送部材とか
ら成る現像剤攪拌搬送手段と、該現像剤攪拌搬送手段と
平行に配設され、内部に固定された磁石と、周面上に回
転可能に支持された現像スリーブとを備え、表面に前記
二成分現像剤を担持する現像剤担持体とを有し、 前記現像剤攪拌搬送手段は、前記第１現像剤攪拌搬送部
材と前記第２現像剤攪拌搬送部材との中間部で前記現像
剤担持体と対向し、前記第１現像剤攪拌搬送部材が、前
記第２現像剤攪拌搬送部材に対して前記現像スリーブの
回転の下流側に位置するように回転可能に支持され、 前記磁石は、前記第１現像剤攪拌搬送部材から現像剤を
汲み上げると共に、前記像担持体と対向する現像領域を
通過した現像剤を前記第２現像剤攪拌搬送部材上に落下
させる磁気拘束力を有することを特徴とする画像形成装
置。5. A photoconductor for forming an electrostatic latent image on a surface thereof, a charging unit for uniformly charging the surface of the photoconductor, an exposure unit for exposing the surface of the photoconductor, a toner and a carrier. A developing device for developing the electrostatic latent image with a two-component developer to form a toner image, a transfer device for transferring the toner image onto a recording medium, and fixing the toner image transferred on the recording medium A developing device comprising: a first developer stirring and conveying member that stirs and conveys a two-component developer including a toner and a carrier in directions opposite to each other across a partition plate; A developer agitating / conveying means comprising a developer agitating / conveying member; a magnet arranged in parallel with the developer agitating / conveying means, fixed inside; and a developing sleeve rotatably supported on a peripheral surface. Carrying the two-component developer on the surface. A developer carrying member, wherein the developer stirring and conveying means faces the developer carrying member at an intermediate portion between the first developer stirring and conveying member and the second developer stirring and conveying member, A first developer stirring and conveying member rotatably supported so as to be positioned downstream of the rotation of the developing sleeve with respect to the second developer stirring and conveying member; An image forming apparatus having a magnetic binding force that draws up the developer from a member and drops the developer that has passed through a development area facing the image carrier onto the second developer stirring and conveying member. 【請求項６】 前記第２現像剤攪拌搬送部材から前記第
１現像剤攪拌搬送部材へ現像剤を受け渡す領域を領域
Ｌ、前記現像剤攪拌搬送部材の軸方向へ現像剤を搬送
し、第１現像剤攪拌搬送部材から第２現像剤攪拌搬送部
材へ現像剤を受け渡す領域を領域Ｍとするとき、 前記磁石は、前記領域Ｌに対向する領域に、現像剤を第
２現像剤攪拌搬送部材から現像スリーブへ汲み上げた
後、前記第１現像剤攪拌搬送部材へ現像剤を受け渡す磁
気拘束力を有し、前記領域Ｍに対向する領域では、現像
剤を保持しないように配置されていることを特徴とする
請求項５に記載の画像形成装置。6. A region L for transferring the developer from the second developer stirring and conveying member to the first developer stirring and conveying member, and conveying the developer in an axial direction of the developer stirring and conveying member. When a region where the developer is transferred from the first developer stirring and conveying member to the second developer stirring and conveying member is defined as a region M, the magnet moves the developer to the region opposite to the region L and transfers the developer to the second developer stirring and conveying member. After being pumped from the member to the developing sleeve, it has a magnetic binding force to transfer the developer to the first developer stirring and conveying member, and is arranged so as not to hold the developer in the region facing the region M. The image forming apparatus according to claim 5, wherein: 【請求項７】 前記領域Ｌに前記現像スリーブから離脱
した現像剤を前記第１現像剤攪拌搬送部材へ誘導する誘
導部材を備えたことを特徴とする請求項５又は請求項６
に記載の画像形成装置。7. The area L further comprises a guide member for guiding the developer detached from the developing sleeve to the first developer stirring and conveying member.
An image forming apparatus according to claim 1. 【請求項８】 前記第２現像剤攪拌搬送部材から前記第
１現像剤攪拌搬送部材へ現像剤を受け渡す領域に、現像
剤搬送部材を備えたことを特徴とする請求項５に記載の
画像形成装置。8. The image according to claim 5, wherein a developer conveying member is provided in an area where the developer is transferred from the second developer stirring and conveying member to the first developer stirring and conveying member. Forming equipment.
JP10981299A 1999-04-16 1999-04-16 Developing device and image forming apparatus Expired - Fee Related JP4093677B2 (en)

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