JPH04338781A - Developing device - Google Patents
Developing deviceInfo
- Publication number
- JPH04338781A JPH04338781A JP11023791A JP11023791A JPH04338781A JP H04338781 A JPH04338781 A JP H04338781A JP 11023791 A JP11023791 A JP 11023791A JP 11023791 A JP11023791 A JP 11023791A JP H04338781 A JPH04338781 A JP H04338781A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic pole
- developing device
- developer
- photoreceptor
- 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
Links
- 230000005291 magnetic effect Effects 0.000 claims abstract description 118
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 7
- 108091008695 photoreceptors Proteins 0.000 claims description 26
- 239000000696 magnetic material Substances 0.000 description 4
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Landscapes
- Magnetic Brush Developing In Electrophotography (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、複写機、プリンタ、フ
ァクシミリなどの画像形成装置に使用する現像装置、特
に感光体に対向する現像ローラの構成に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine, a printer, or a facsimile, and particularly to the structure of a developing roller facing a photoreceptor.
【０００２】0002
【従来の技術】従来、図５に示す現像ローラを備えた現
像装置が提案されている。この現像装置において、感光
体１０に対向する現像ローラ１は、非回転状態に固定さ
れた円柱状の磁石体２と、この磁石体２に外装されたス
リーブ３とで構成されている。前記磁石体２の外周部に
は軸方向に延在する複数の磁極Ｓ１，Ｎ１，Ｎ２，Ｓ２
，…が着磁され、隣接した同一極性の磁極Ｎ１，Ｎ２が
感光体１０の対向部に配置されている。2. Description of the Related Art Conventionally, a developing device equipped with a developing roller shown in FIG. 5 has been proposed. In this developing device, a developing roller 1 facing a photoreceptor 10 is composed of a cylindrical magnet body 2 fixed in a non-rotating state and a sleeve 3 wrapped around the magnet body 2. A plurality of magnetic poles S1, N1, N2, S2 extending in the axial direction are provided on the outer periphery of the magnet body 2.
, . . . are magnetized, and adjacent magnetic poles N1 and N2 of the same polarity are arranged on the opposing portion of the photoreceptor 10.
【０００３】前記現像装置では、トナーとキャリアとか
らなる二成分現像剤が磁石体２の磁力によってスリーブ
３の外周部に保持される。この現像剤はスリーブ３の回
転と共に矢印ａ方向に搬送され、スリーブ３に微小ギャ
ップを隔てて対向するブレード４の対向部で搬送量が一
定に規制されたのち磁極Ｎ１，Ｎ２の対向部に搬送され
る。磁極Ｎ１，Ｎ２の対向部では、現像剤は磁界Ｈ１，
Ｈ２の磁力線に沿って磁気ブラシを形成し、磁界Ｈ１，
Ｈ２の間に形成された反発磁界Ｈ０の影響によって磁極
Ｎ１の対向部で現像剤は溜まりを形成して、ここで三次
元方向に撹乱される。したがって、矢印ｂ方向から移動
してくる感光体１０の静電潜像に現像剤が接触すると、
この静電潜像に対して前記溜まり部分の現像剤からトナ
ーが供給されてトナー像が形成される。[0003] In the developing device, a two-component developer consisting of toner and carrier is held on the outer periphery of the sleeve 3 by the magnetic force of the magnet body 2 . This developer is conveyed in the direction of arrow a as the sleeve 3 rotates, and after the amount of conveyance is regulated to a constant by the opposing part of the blade 4 that faces the sleeve 3 with a small gap in between, it is conveyed to the opposing part of the magnetic poles N1 and N2. be done. At the opposing portions of magnetic poles N1 and N2, the developer is exposed to magnetic fields H1,
A magnetic brush is formed along the magnetic field line of H2, and the magnetic field H1,
Due to the influence of the repulsive magnetic field H0 formed during H2, the developer forms a pool at the opposing portion of the magnetic pole N1, where it is disturbed in a three-dimensional direction. Therefore, when the developer comes into contact with the electrostatic latent image on the photoreceptor 10 moving from the direction of arrow b,
Toner is supplied from the developer in the pooled portion to this electrostatic latent image to form a toner image.
【０００４】0004
【発明が解決しようとする課題】しかしながら、前記現
像装置では、使用する現像剤の種類によっては磁極Ｎ１
の対向部に十分な大きさの現像剤溜まりを形成すること
ができないという問題点があった。また、前記現像装置
では、磁極Ｎ１，Ｎ２は磁石体２を直接磁化して形成さ
れているので、小径の現像ローラでは、互いに近接した
これらの磁極を高磁力に設定することは勿論、それらに
磁力差を設けることは殆ど不可能であった。具体的に説
明すると、直径約２０〜３０ｍｍの磁石体では、磁極Ｎ
１と磁極Ｎ２の中心角αを３０゜に設定した場合、磁極
Ｎ１，Ｎ２を７００〜８００ガウス程度までしか磁化す
ることができなかった。そのため、磁極Ｎ１，Ｎ２の周
囲では現像剤の拘束力が弱く、キャリアがスリーブから
離脱して感光体１０に付着し、その結果画質不良を招く
という問題点を有していた。[Problems to be Solved by the Invention] However, in the above-mentioned developing device, depending on the type of developer used, the magnetic pole N1
There was a problem in that a sufficiently large developer reservoir could not be formed in the opposing portion. In addition, in the developing device, the magnetic poles N1 and N2 are formed by directly magnetizing the magnet body 2. Therefore, in the case of a small-diameter developing roller, it is necessary to set these magnetic poles close to each other to a high magnetic force. It was almost impossible to create a magnetic force difference. To explain specifically, in a magnet body with a diameter of about 20 to 30 mm, the magnetic pole N
When the central angle α between the magnetic pole N1 and the magnetic pole N2 was set to 30°, the magnetic poles N1 and N2 could only be magnetized to about 700 to 800 Gauss. Therefore, the restraint force of the developer is weak around the magnetic poles N1 and N2, resulting in a problem in that the carrier detaches from the sleeve and adheres to the photoreceptor 10, resulting in poor image quality.
【０００５】[0005]
【課題を解決するための手段】そこで、本発明は前記問
題点を解決するためになされたもので、磁石体の感光体
対向領域に同一極性の二つの磁極を隣接して設け、前記
二つの磁極はスリーブ回転方向上流側の第１磁極を下流
側の第２磁極よりも高磁力に設定し、前記第１磁極に保
持された現像剤を感光体に接触させてある。また、前記
二つの磁極の少なくともいずれか一方が前記磁石体に埋
め込まれた別部材の磁性体を着磁して形成されている。[Means for Solving the Problems] Therefore, the present invention has been made to solve the above-mentioned problems. Two magnetic poles of the same polarity are provided adjacently in the area of the magnet body facing the photoreceptor, and the two magnetic poles are As for the magnetic poles, a first magnetic pole on the upstream side in the rotational direction of the sleeve is set to have a higher magnetic force than a second magnetic pole on the downstream side, and the developer held by the first magnetic pole is brought into contact with the photoreceptor. Further, at least one of the two magnetic poles is formed by magnetizing a separate magnetic body embedded in the magnet body.
【０００６】[0006]
【作用】前記構成の現像装置では、第１磁極に保持され
た現像剤が感光体に接触して現像が行われる。ここでの
現像剤は磁極間に存在する反発磁界の影響によって溜ま
りを形成しており、この溜まりの中で現像剤は三次元方
向に撹乱される。また、第１磁極を第２磁極よりも高磁
力に設定することで、現像剤の種類に拘わらず前記現像
剤溜まりが大きくなり、感光体への現像剤接触効率が良
く、静電潜像は高濃度状態で現像される。さらに、現像
剤は高磁力の第１磁極によって保持されるので、現像剤
の中からキャリアが分離して感光体に付着することはな
い。そして、第１磁極、第２磁極の少なくともいずれか
一方を埋め込み磁石に形成すれば、小径の磁石体であっ
ても両磁極間に必要な磁力差を確保することができる。[Operation] In the developing device having the above structure, the developer held by the first magnetic pole comes into contact with the photoreceptor to perform development. The developer here forms a pool under the influence of the repulsive magnetic field existing between the magnetic poles, and the developer is disturbed in three dimensions within this pool. Furthermore, by setting the first magnetic pole to have a higher magnetic force than the second magnetic pole, the developer pool becomes larger regardless of the type of developer, the developer contacts the photoreceptor with better efficiency, and the electrostatic latent image is Developed in a high density state. Furthermore, since the developer is held by the first magnetic pole with high magnetic force, the carrier does not separate from the developer and adhere to the photoreceptor. If at least one of the first magnetic pole and the second magnetic pole is formed as an embedded magnet, a necessary difference in magnetic force between the two magnetic poles can be ensured even if the magnet body has a small diameter.
【０００７】[0007]
【実施例】以下、添付図面を参照して本発明の実施例に
ついて説明する。
（１）第１実施例
図１に示す本実施例の現像ローラ１では、磁石体２の感
光体対向部に軸方向に沿って溝５が形成され、この溝５
に磁極Ｎ１を着磁した磁石６が埋め込まれている。ここ
で、磁石体２は等方性酸化物の磁性体で、磁極Ｓ１，Ｎ
２，Ｓ２，…は磁石体２の周囲を直接磁化して形成され
、磁極Ｎ２の磁力は７００〜１０００ガウス、磁極Ｓ１
の磁力は６００ガウス、磁極Ｓ２の磁力は８００ガウス
に設定されている。一方、埋め込み磁石６は異方性酸化
物または希土類の磁性体で、磁極Ｎ１の磁力は１２００
〜１５００ガウスに設定されている。これにより、現像
ローラ１の感光体対向領域における磁束は、図１におい
て点線で示す状態に分布している。その他の構成は図５
に示す従来の現像装置と同一であり、同一部材等には同
一符号を付して説明を省略する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. (1) First Example In the developing roller 1 of this example shown in FIG.
A magnet 6 with a magnetic pole N1 magnetized is embedded in the. Here, the magnet body 2 is an isotropic oxide magnetic body, and the magnetic poles S1, N
2, S2, .
The magnetic force of the magnetic pole S2 is set to 600 Gauss, and the magnetic force of the magnetic pole S2 is set to 800 Gauss. On the other hand, the embedded magnet 6 is made of an anisotropic oxide or rare earth magnetic material, and the magnetic force of the magnetic pole N1 is 1200
It is set to ~1500 Gauss. As a result, the magnetic flux in the area of the developing roller 1 facing the photoreceptor is distributed as shown by the dotted line in FIG. Other configurations are shown in Figure 5.
The developing device is the same as the conventional developing device shown in FIG.
【０００８】前記現像装置では、図２に示すように、感
光体対向部に搬送されてきた現像剤は磁極Ｎ１の対向部
で溜まりを形成し、三次元方向に撹乱されながら感光体
１０に接触する。また、磁極Ｎ１が磁極Ｎ２に比べて高
磁力に設定されているので前記現像剤溜まり量が多く、
感光体１０に対する現像剤の接触幅が広いので、静電潜
像は効率良く現像される。一方、磁極Ｎ１の磁力は高磁
力に設定されているので、現像剤からキャリアが分離し
て感光体１０に付着することはない。In the developing device, as shown in FIG. 2, the developer conveyed to the photoreceptor facing portion forms a pool at the portion facing the magnetic pole N1, and comes into contact with the photoreceptor 10 while being disturbed in three-dimensional directions. do. In addition, since the magnetic pole N1 is set to have a higher magnetic force than the magnetic pole N2, the amount of developer accumulated is large.
Since the contact width of the developer with respect to the photoreceptor 10 is wide, the electrostatic latent image is efficiently developed. On the other hand, since the magnetic force of the magnetic pole N1 is set to a high magnetic force, the carrier does not separate from the developer and adhere to the photoreceptor 10.
【０００９】次に、現像剤は磁極Ｎ２の対向部に移動す
る。ここで、磁極Ｎ１と磁極Ｎ２の中間領域における磁
力を磁極Ｎ１の５０〜９０％に設定すれば当該領域にも
磁気ブラシが形成される。したがって、この中間領域の
磁気ブラシを感光体に接触させて現像を行ってもよい。
この場合、中間領域の磁気ブラシは磁極Ｎ１の対向部に
おける磁気ブラシよりも柔らかく、感光体に対する接触
力も小さいので、磁極Ｎ１の対向部で形成されたトナー
像が離れ際の磁気ブラシによって乱されることがなく、
最終的に作成された画像上にかすれ模様等が現れること
もない。Next, the developer moves to a portion facing the magnetic pole N2. Here, if the magnetic force in the intermediate region between the magnetic poles N1 and N2 is set to 50 to 90% of that of the magnetic pole N1, a magnetic brush is also formed in that region. Therefore, development may be performed by bringing the magnetic brush in this intermediate region into contact with the photoreceptor. In this case, the magnetic brush in the intermediate region is softer than the magnetic brush in the opposing portion of the magnetic pole N1, and its contact force with respect to the photoreceptor is smaller, so the toner image formed in the opposing portion of the magnetic pole N1 is disturbed by the magnetic brush at the edge of separation. Without a problem,
No blurred pattern or the like will appear on the finally created image.
【００１０】一方、中間領域を無磁力状態にすると、磁
極Ｎ１の対向部を通過した現像剤は磁極Ｎ２の対向部に
飛翔して移動する。したがって、この飛翔する現像剤を
感光体に接触させて現像を行なうようにしてもよい。こ
の場合、いわゆるカスケードまたはパウダークラウド的
な現像が行われることになる。On the other hand, when the intermediate region is brought into a non-magnetic state, the developer that has passed through the portion facing the magnetic pole N1 flies and moves to the portion facing the magnetic pole N2. Therefore, development may be performed by bringing this flying developer into contact with the photoreceptor. In this case, so-called cascade or powder cloud type development is performed.
【００１１】なお、前記実施例では、スリーブ回転方向
上流側の磁極Ｎ１だけを埋め込み磁石６に形成するもの
としたが、磁極Ｎ１に代えて磁極Ｎ２の位置に磁性体を
埋め込み、この磁性体に磁極Ｎ２を形成するようにして
もよい。In the above embodiment, only the magnetic pole N1 on the upstream side in the rotational direction of the sleeve was formed in the embedded magnet 6, but instead of the magnetic pole N1, a magnetic material was embedded at the position of the magnetic pole N2, and this magnetic material A magnetic pole N2 may also be formed.
【００１２】（２）第２実施例
図３に第２実施例の現像装置を示す。この実施例では、
磁石体２の感光体対向部に溝５が形成されている。また
、埋め込み磁石６には軸方向に沿って溝６ａが形成され
、この溝６ａを挾む両端部分に磁極Ｎ１，Ｎ２が着磁さ
れており、磁石６は溝部６ａを感光体１０に対向させて
溝５に埋め込まれている。ここで、磁極Ｎ１，Ｎ２の磁
力はそれぞれ前記実施例と同様に、磁極Ｎ１が１２００
〜１５００ガウス、磁極Ｎ２が７００〜１０００ガウス
に設定されている。したがって、本実施例の現像装置も
、前記第１実施例の現像装置と同様に、静電潜像を効率
良く現像し、かつ感光体１０へのキャリア付着も防止す
ることができる。なお、磁極Ｎ１と磁極Ｎ２の磁力差は
、溝６ａを挾む着磁部分の大きさを違えるか、図４に示
すように磁極Ｎ２を着磁する部分の感光体対向領域６ｂ
を一部切除して確保されている。(2) Second Embodiment FIG. 3 shows a developing device of a second embodiment. In this example,
A groove 5 is formed in a portion of the magnet 2 facing the photoreceptor. Further, a groove 6a is formed in the embedded magnet 6 along the axial direction, and magnetic poles N1 and N2 are magnetized at both ends sandwiching the groove 6a. It is embedded in the groove 5. Here, the magnetic forces of the magnetic poles N1 and N2 are respectively similar to the above embodiment, and the magnetic force of the magnetic pole N1 is 1200
~1500 Gauss, and magnetic pole N2 is set to 700~1000 Gauss. Therefore, like the developing device of the first embodiment, the developing device of this embodiment can efficiently develop an electrostatic latent image and also prevent carrier adhesion to the photoreceptor 10. The difference in magnetic force between the magnetic poles N1 and N2 can be determined by changing the size of the magnetized portions that sandwich the groove 6a, or by changing the size of the magnetized portions that sandwich the groove 6a, or by changing the size of the photoreceptor facing region 6b of the portion where the magnetic pole N2 is magnetized, as shown in FIG.
It was secured by partially removing it.
【００１３】[0013]
【発明の効果】以上の説明で明らかなように、本発明は
、感光体対向領域に同一極性の二つの磁極を隣接して設
け、前記二つの磁極はスリーブ回転方向上流側の第１磁
極が下流側の第２磁極よりも高磁力に設定され、前記第
１磁極に保持された現像剤を感光体に接触させている。
したがって、現像剤の種類に拘わり無く第１磁極の対向
部に大きな現像剤溜まりが形成され、常に効率の良い現
像が行われる。また、強磁力の第１磁極に保持された現
像剤からキャリアが分離して感光体に付着することがな
く、キャリア付着の無い良質な画像を得ることができる
。As is clear from the above description, the present invention provides two magnetic poles of the same polarity adjacent to each other in the area facing the photoconductor, and the first magnetic pole on the upstream side in the direction of rotation of the sleeve is the first magnetic pole. The magnetic force is set higher than that of the second magnetic pole on the downstream side, and the developer held by the first magnetic pole is brought into contact with the photoreceptor. Therefore, regardless of the type of developer, a large developer pool is formed in the opposing portion of the first magnetic pole, and efficient development is always performed. In addition, the carrier does not separate from the developer held by the first magnetic pole of ferromagnetic force and adhere to the photoreceptor, making it possible to obtain high-quality images without carrier adhesion.
【００１４】また、第１磁極、第２磁極の少なくともい
ずれか一方を別部材の磁性体に形成することで、小径の
現像ローラにあっても第１磁極と第２磁極の間に十分な
磁力差を確保することができる。Furthermore, by forming at least one of the first magnetic pole and the second magnetic pole as a separate magnetic material, sufficient magnetic force can be maintained between the first magnetic pole and the second magnetic pole even in the case of a small-diameter developing roller. The difference can be secured.
【図１】 第１実施例の現像装置の部分断面図である
。FIG. 1 is a partial cross-sectional view of a developing device according to a first embodiment.
【図２】 第１実施例の現像装置の部分拡大断面図で
ある。FIG. 2 is a partially enlarged sectional view of the developing device of the first embodiment.
【図３】 第２実施例の現像装置の部分断面図である
。FIG. 3 is a partial cross-sectional view of a developing device according to a second embodiment.
【図４】 第２実施例の現像装置の部分拡大断面図で
ある。FIG. 4 is a partially enlarged sectional view of the developing device of the second embodiment.
【図５】 従来の現像装置の部分断面図である。FIG. 5 is a partial cross-sectional view of a conventional developing device.
１…現像ローラ ２…磁石体 ３
…スリーブ ５…溝
６…埋め込み磁石 １０…感光体Ｎ１…上流側磁
極（第１磁極） Ｎ２…下流側磁極（第２磁
極）1...Developing roller 2...Magnet 3
...Sleeve 5...Groove 6...Embedded magnet 10...Photoreceptor N1...Upstream magnetic pole (first magnetic pole) N2...Downstream magnetic pole (second magnetic pole)
Claims (2)
ーブ外装し、該スリーブの回転に基づいてその外周に保
持された現像剤を感光体に接触させて現像を行なう現像
装置において、前記磁石体の感光体対向領域に同一極性
の二つの磁極を隣接して設け、前記二つの磁極はスリー
ブ回転方向上流側の第１磁極を下流側の第２磁極よりも
高磁力に設定し、前記第１磁極に保持された現像剤を感
光体に接触させたことを特徴とする現像装置。1. A developing device in which a magnet body fixed in a non-rotating state is covered with a sleeve, and development is performed by bringing the developer held on the outer periphery of the sleeve into contact with a photoreceptor based on the rotation of the sleeve, wherein the magnet body is Two magnetic poles of the same polarity are provided adjacently in a region of the body facing the photoconductor, and the first magnetic pole on the upstream side in the rotational direction of the sleeve is set to have a higher magnetic force than the second magnetic pole on the downstream side. A developing device characterized in that a developer held by one magnetic pole is brought into contact with a photoreceptor.
一方が前記磁石体に埋め込まれた別部材の磁性体を着磁
して形成されていることを特徴とする前記請求項１の現
像装置。2. The developing device according to claim 1, wherein at least one of the two magnetic poles is formed by magnetizing a separate magnetic body embedded in the magnet body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11023791A JPH04338781A (en) | 1991-05-15 | 1991-05-15 | Developing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11023791A JPH04338781A (en) | 1991-05-15 | 1991-05-15 | Developing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04338781A true JPH04338781A (en) | 1992-11-26 |
Family
ID=14530585
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11023791A Pending JPH04338781A (en) | 1991-05-15 | 1991-05-15 | Developing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04338781A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0693715A2 (en) | 1994-07-22 | 1996-01-24 | Hitachi, Ltd. | Developing apparatus |
| US5860049A (en) * | 1996-06-05 | 1999-01-12 | Hitachi, Ltd. | Developing apparatus and picture image forming apparatus |
-
1991
- 1991-05-15 JP JP11023791A patent/JPH04338781A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0693715A2 (en) | 1994-07-22 | 1996-01-24 | Hitachi, Ltd. | Developing apparatus |
| US5574546A (en) * | 1994-07-22 | 1996-11-12 | Hitachi, Ltd. | Developing apparatus for an electrophotographic machine |
| US5860049A (en) * | 1996-06-05 | 1999-01-12 | Hitachi, Ltd. | Developing apparatus and picture image forming apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6775505B2 (en) | Electrostatic image developing process with optimized setpoints | |
| US3952701A (en) | Electrostatic developing apparatus | |
| JPS58186768A (en) | Developing device | |
| EP0182630B1 (en) | Electrophotographic development device | |
| JPH04338781A (en) | Developing device | |
| US6785498B2 (en) | Development system for developing an image on an image bearing member | |
| JP2861681B2 (en) | Image forming device | |
| JPH04338782A (en) | Developing device | |
| JP3109314B2 (en) | Magnet roll and manufacturing method thereof | |
| JPH08305170A (en) | Image recorder | |
| JP2725686B2 (en) | Magnetic brush developing device | |
| JP2984193B2 (en) | Multicolor image forming device | |
| JPS6017470A (en) | Developing device | |
| JPS5926369Y2 (en) | Electrostatic recording magnet roll | |
| JP3142034B2 (en) | Apparatus and method for charging photoreceptor | |
| JPH06167887A (en) | Image forming device | |
| JPS62183478A (en) | Developing device | |
| JP3092427B2 (en) | Developing device | |
| JPH1039599A (en) | Developing device | |
| JPS5895370A (en) | Developing device | |
| JPH02219076A (en) | Dry developing device | |
| JPS60176071A (en) | Developing device | |
| JPH0527546A (en) | Multicolor image forming device | |
| JPH01257983A (en) | Carrier recovering device | |
| JP2003149945A (en) | Developing device |