JPH1152731A - Developing device - Google Patents
Developing deviceInfo
- Publication number
- JPH1152731A JPH1152731A JP22071197A JP22071197A JPH1152731A JP H1152731 A JPH1152731 A JP H1152731A JP 22071197 A JP22071197 A JP 22071197A JP 22071197 A JP22071197 A JP 22071197A JP H1152731 A JPH1152731 A JP H1152731A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- magnetic pole
- developer
- magnet plate
- 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
Links
Landscapes
- Magnetic Brush Developing In Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電子写真方式ある
いは静電記録方式を採用した画像形成で用いられる現像
装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for image formation employing an electrophotographic system or an electrostatic recording system.
【０００２】[0002]
【従来の技術】従来より、電子写真方式や静電記録方式
により、像担持体上に静電潜像を形成し、その潜像を現
像装置により１成分現像剤あるいは２成分現像剤を用い
て現像することが行なわれている。このような現像装置
としては、従来から種々のものが提案されているが、そ
の代表例を図８に示す。2. Description of the Related Art Conventionally, an electrostatic latent image is formed on an image carrier by an electrophotographic method or an electrostatic recording method, and the latent image is formed by a developing device using a one-component developer or a two-component developer. Developing is being done. Various such developing devices have been conventionally proposed, and a typical example is shown in FIG.
【０００３】図８に示す現像装置１は、現像剤を収容し
た現像容器２を備え、この現像容器２内にスクリュー
４、６が配設され、これらのスクリュー４、６によって
現像剤が現像容器２内で往復循環される。現像剤は、磁
性粒子を含む現像剤、すなわち樹脂中に磁性粒子を混練
した磁性トナーからなる１成分現像剤、または磁性粒子
を主成分とする磁性キャリアと非磁性トナーを混合した
２成分現像剤とされる。A developing device 1 shown in FIG. 8 includes a developing container 2 containing a developer, and screws 4 and 6 are disposed in the developing container 2, and the developer is conveyed by the screws 4 and 6. It is reciprocated in 2. The developer is a developer containing magnetic particles, that is, a one-component developer composed of a magnetic toner in which magnetic particles are kneaded in a resin, or a two-component developer in which a magnetic carrier containing magnetic particles as a main component and a non-magnetic toner are mixed. It is said.
【０００４】現像装置１は、像担持体１００と対面した
開口部に現像スリーブ１０を有し、この現像スリーブ１
０は、図９に示すように、その両端の軸１０ａを現像容
器２の両側の側壁２ａ（図９には片側のみ図示した）に
軸受け１６を介して取り付けることにより、回転自在に
支持されている。現像スリーブ１０の内側にはマグネッ
トローラ１２が配置され、このマグネットローラ１２
は、その一端の図示しない軸部を側壁２ａに固定するこ
とにより、現像スリーブ１０内で非回転とされている。
現像スリーブ１０上の現像容器２の部分には、現像スリ
ーブ１０と所定の間隙を開けて磁性材料製の規制ブレー
ド１４が設けられている。[0004] The developing device 1 has a developing sleeve 10 at an opening facing the image carrier 100.
9 is supported rotatably by attaching shafts 10a at both ends thereof to side walls 2a (only one side is shown in FIG. 9) of both sides of the developing container 2 as shown in FIG. I have. A magnet roller 12 is disposed inside the developing sleeve 10.
Is fixed in the developing sleeve 10 by fixing a shaft (not shown) at one end thereof to the side wall 2a.
A regulating blade 14 made of a magnetic material is provided at a part of the developing container 2 on the developing sleeve 10 with a predetermined gap from the developing sleeve 10.
【０００５】マグネットローラ１２は、その周囲に５つ
の磁極Ｎ1 〜Ｎ3 、Ｓ1 〜Ｓ2 を有する。このうち、磁
極Ｓ1 は現像主極で、像担持体１００と現像スリーブ１
０とが対向した現像部に位置し、同極の磁極Ｎ3 、Ｎ2
は反撥磁極で、現像スリーブ１０の矢印の回転方向に関
して現像部よりも下流の現像容器２内に位置する。この
反撥磁極のうちの上流側の磁極Ｎ3 は現像剤取り込み
極、下流側の磁極Ｎ2 は現像剤汲み上げ極である。[0005] The magnet roller 12 has five magnetic poles N1 to N3 and S1 to S2 around it. The magnetic pole S1 is a main developing pole, and the image carrier 100 and the developing sleeve 1
0 is located in the developing section opposite to the magnetic poles N3 and N2 of the same polarity.
Denotes a repelling magnetic pole, which is located in the developing container 2 downstream of the developing unit in the rotation direction of the arrow of the developing sleeve 10. Of the repelling magnetic poles, the upstream magnetic pole N3 is a developer intake pole, and the downstream magnetic pole N2 is a developer pumping pole.
【０００６】現像容器２内の現像剤は、回転する現像ス
リーブ１０の表面上に磁極Ｎ2 の作用により汲み上げら
れ、汲み上げられた現像剤は、現像スリーブ１０の回転
にともない、磁極Ｓ2 →磁極Ｎ1 →磁極Ｓ1 と搬送さ
れ、その途上で、規制ブレード１４により層厚が規制さ
れて、現像剤薄層に形成される。現像部に搬送された現
像剤は、磁極Ｓ1 の磁力により穂立ちして像担持体１０
０の表面に接触し、像担持体１００上に形成された静電
潜像を現像する。現像部を経て現像を終了した現像剤
は、現像スリーブ１０の回転に従い現像容器２内に取り
込まれ、磁極Ｎ3 およびＮ2 による反撥磁界で現像スリ
ーブ１０上から剥離されて、現像容器２内に落下し回収
される。The developer in the developing container 2 is pumped up on the surface of the rotating developing sleeve 10 by the action of the magnetic pole N 2, and the pumped up developer is rotated by the magnetic pole S 2 → magnetic pole N 1 → The toner is conveyed to the magnetic pole S1, and on the way, the layer thickness is regulated by the regulating blade 14 to form a thin developer layer. The developer conveyed to the developing section is raised by the magnetic force of the magnetic pole S1 and rises up.
The electrostatic latent image formed on the image carrier 100 is developed by contacting the surface of the image carrier 100. The developer, which has been developed through the developing section, is taken into the developing container 2 according to the rotation of the developing sleeve 10, is separated from the developing sleeve 10 by the repelling magnetic field generated by the magnetic poles N3 and N2, and falls into the developing container 2. Collected.
【０００７】ところで、現像容器２内の現像剤は、容器
２内での循環移動によって、現像スリーブ１０の表面に
沿って軸受け１６の部分へ移送される。このため、現像
剤が軸受け１６の部分に侵入して、軸受け１６内に溜っ
てその機能を阻害し、現像スリーブ１０の円滑な回転を
不可能としたり、現像剤が軸受け１６の部分を通過し
て、現像容器２外に現像剤が漏れたり、飛散することが
あった。By the way, the developer in the developing container 2 is transferred to the bearing 16 along the surface of the developing sleeve 10 by the circulating movement in the container 2. As a result, the developer enters the bearing 16 and accumulates in the bearing 16 to inhibit its function, making it impossible for the developing sleeve 10 to rotate smoothly, or causing the developer to pass through the bearing 16. As a result, the developer may leak or scatter outside the developing container 2.
【０００８】そこで、これを防ぐために、図９に示すよ
うに、現像容器２の両側の各側壁２ａの内面に、現像ス
リーブ１０の端部の周面を非接触に包囲する磁性板１８
を取り付けている。In order to prevent this, as shown in FIG. 9, a magnetic plate 18 surrounding the peripheral surface of the end of the developing sleeve 10 in a non-contact manner is provided on the inner surface of each side wall 2a on both sides of the developing container 2.
Is installed.
【０００９】この磁性板１８は、鉄、ニッケル、コバル
ト、またはそれらの合金等の強磁性材料で作製するのが
好ましく、厚さは０．２〜１ｍｍ程度とされる。これら
の強磁性材料は、（１／２）・（ＢＨ）max が０．７Ｊ
／ｍ2 以下である。ただし、Ｂは残留磁束密度、Ｈは保
磁力で、（ＢＨ）max はエネルギー積（Ｂ×Ｈ）の最大
値である最大エネルギー積を示す。The magnetic plate 18 is preferably made of a ferromagnetic material such as iron, nickel, cobalt, or an alloy thereof, and has a thickness of about 0.2 to 1 mm. These ferromagnetic materials have a (1/2) · (BH) max of 0.7 J
/ M 2 or less. Here, B is the residual magnetic flux density, H is the coercive force, and (BH) max indicates the maximum energy product which is the maximum value of the energy product (B × H).
【００１０】磁性板１８と現像スリーブ１０の周面との
間の空隙は、限定されるものではないが、０．３〜２ｍ
ｍの範囲で適当に設定される。磁性板１８は、現像スリ
ーブ１０の周面全周にわたって配置するのが好ましい
が、図８に示すように、現像容器２内側の現像スリーブ
１０の部分だけとすることもできる。また磁性板１８
は、現像スリーブ１０と同心の環状板に形成したが、現
像スリーブ１０との間に一様な空隙を設けることができ
れば、必ずしも環状でなくてもよく、種々の形状を取る
ことができる。磁性板１８の板面が現像スリーブ１０の
軸の直交面に対してなす角度は、現像剤の漏出をより確
実に防ぐ点から２０°以下とすることが好ましい。The gap between the magnetic plate 18 and the peripheral surface of the developing sleeve 10 is not limited, but may be 0.3 to 2 m.
It is set appropriately within the range of m. The magnetic plate 18 is preferably disposed over the entire peripheral surface of the developing sleeve 10, but may be provided only on the developing sleeve 10 inside the developing container 2 as shown in FIG. The magnetic plate 18
Is formed in an annular plate concentric with the developing sleeve 10. However, as long as a uniform gap can be provided between the developing sleeve 10 and the developing sleeve 10, the annular shape is not necessarily required. The angle formed by the plate surface of the magnetic plate 18 with respect to the plane orthogonal to the axis of the developing sleeve 10 is preferably 20 ° or less in order to more reliably prevent leakage of the developer.
【００１１】この現像スリーブ１０の端部に配置した磁
性板１８は、現像スリーブ１０内のマグネットローラ８
の磁力によって磁化され、磁性板１８とマグネットロー
ラ８との間に磁気回路が形成されて、現像スリーブ１０
側の磁性板１８の先端部に磁界が集中し、この磁界によ
り、磁性板１８と現像スリーブ１０との間の空隙に現像
剤による密な磁気ブラシが形成される。この磁気ブラシ
は端部シールとしての機能を有し、現像容器２内での往
復循環により、現像スリーブ１０の表面に沿って現像容
器２内から移送されてくる現像剤を、磁気ブラシが磁性
板１８と現像スリーブ１０との間で遮断する作用をな
す。The magnetic plate 18 disposed at the end of the developing sleeve 10
And a magnetic circuit is formed between the magnetic plate 18 and the magnet roller 8 so that the developing sleeve 10
The magnetic field concentrates on the tip of the magnetic plate 18 on the side, and this magnetic field forms a dense magnetic brush of the developer in the gap between the magnetic plate 18 and the developing sleeve 10. The magnetic brush has a function as an end seal. The magnetic brush transfers the developer transferred from the inside of the developing container 2 along the surface of the developing sleeve 10 by reciprocating circulation in the developing container 2. The function of blocking between the developing sleeve 18 and the developing sleeve 10 is achieved.
【００１２】しかしながら、上記の磁性板１８とマグネ
ットローラ８とによる磁気ブラシでは、現像剤が現像容
器２の側壁２ａと現像スリーブ１０との間の隙間を通過
するのを完全に遮断することができず、現像剤が軸受け
１６の部分を経て現像容器２外に漏れたり、飛散したり
することが少なからず生じる。However, the magnetic brush formed by the magnetic plate 18 and the magnet roller 8 can completely block the developer from passing through the gap between the side wall 2a of the developing container 2 and the developing sleeve 10. In other words, the developer leaks or scatters out of the developing container 2 via the bearing 16 to some extent.
【００１３】図１０に、非接触式の磁束密度測定器によ
り測定した、現像スリーブ１０表面の磁束密度の周方向
上の分布を示す。磁束密度は、現像スリーブ１０の長手
方向の中央部付近で測定した。図に示すように、磁束密
度分布には、現像スリーブ１０内のマグネットローラ８
の磁極Ｓ1 、Ｓ2 、Ｎ1 、Ｎ2 、Ｎ3 に対応したピーク
が現れ、また反撥磁極Ｎ2 とＮ3 に対応したピークの間
には、これら反撥磁極Ｎ2 とＮ3 による磁束密度が低い
反撥磁界領域が現れる。反撥磁界領域の磁束密度がほぼ
０の中心位置をＲで示す。FIG. 10 shows a circumferential distribution of the magnetic flux density on the surface of the developing sleeve 10 measured by a non-contact type magnetic flux density measuring device. The magnetic flux density was measured near the longitudinal center of the developing sleeve 10. As shown in the figure, the magnetic flux density distribution includes the magnet roller 8 in the developing sleeve 10.
Peaks corresponding to the magnetic poles S1, S2, N1, N2, and N3 appear, and between the peaks corresponding to the repulsive magnetic poles N2 and N3, a repulsive magnetic field region having a low magnetic flux density due to the repulsive magnetic poles N2 and N3 appears. The center position where the magnetic flux density in the repelling magnetic field region is almost 0 is indicated by R.
【００１４】図１１に、非接触式の磁束密度測定器によ
り測定した、現像スリーブ１０表面の磁束密度の軸方向
上の分布を示す。磁束密度は、現像スリーブ１０の両端
部に磁性板１８を配置しない状態で測定した。図１１
（ａ）は磁極Ｎ3 の位置（Ｎ3極位相）における磁束密
度分布、図１１（ｂ）は反撥磁界領域の中心位置Ｒ（Ｒ
位相）における磁束密度分布である。FIG. 11 shows the axial distribution of the magnetic flux density on the surface of the developing sleeve 10 measured by a non-contact type magnetic flux density measuring device. The magnetic flux density was measured in a state where the magnetic plates 18 were not disposed at both ends of the developing sleeve 10. FIG.
(A) is a magnetic flux density distribution at the position of the magnetic pole N3 (N3 pole phase), and (b) is a center position R (R
(Phase).
【００１５】図１１（ｂ）に示すように、反撥磁界領域
の中心位置Ｒでは、磁力（Ｎ極）は元々弱いことに加え
て、磁性板１８の外方で磁力が逆極性（Ｓ極）に反転す
るため、反撥磁界領域の中心位置Ｒ上における磁性板１
８の対向部分では、現像スリーブ１０表面の磁束密度は
ほぼ０となる。このため、反撥磁界領域の中心位置Ｒが
位置した部分の、磁性板１８と現像スリーブ１０との間
の空隙は、磁性板１８が設けられている現像スリーブ１
０の周方向の他の部分における空隙と比べて、現像剤の
磁気ブラシが弱く形成されるか、磁気ブラシの形成がほ
とんどない。従って、反撥磁界領域の中心位置Ｒ近辺
の、磁性板１８と現像スリーブ１０との間の空隙部分か
ら、現像剤が漏れもしくは飛散してしまうことがあっ
た。As shown in FIG. 11B, at the center position R of the repulsion magnetic field region, the magnetic force (N pole) is originally weak, and the magnetic force is opposite to the polarity (S pole) outside the magnetic plate 18. The magnetic plate 1 on the center position R of the repulsion magnetic field region.
8, the magnetic flux density on the surface of the developing sleeve 10 becomes almost zero. For this reason, the gap between the magnetic plate 18 and the developing sleeve 10 in the portion where the center position R of the repelling magnetic field region is located is the developing sleeve 1 on which the magnetic plate 18 is provided.
The magnetic brush of the developer is formed weaker or hardly formed as compared with the gap in the other portion of the circumferential direction of 0. Therefore, the developer may leak or scatter from the gap between the magnetic plate 18 and the developing sleeve 10 near the center position R of the repelling magnetic field region.
【００１６】反撥磁界領域の中心位置Ｒ以外、たとえば
磁極Ｎ3 のところでも、現像スリーブ１０と磁性板１８
との間で磁気ブラシが形成されるものの、磁極Ｎ3 の外
側の現像スリーブ１０の端部部分（最端部）では、逆極
の磁力が発生するために、現像剤の漏れ等が発生するこ
とがあった。The developing sleeve 10 and the magnetic plate 18 are located at a position other than the center position R of the repelling magnetic field region, for example, at the magnetic pole N3.
Although a magnetic brush is formed between the two, a magnetic force of the opposite polarity is generated at the end portion (outmost end) of the developing sleeve 10 outside the magnetic pole N3, so that leakage of the developer occurs. was there.
【００１７】そこで、その対策として、先の図９に同時
に示したように、磁性板１８の外側において、現像スリ
ーブ１０の両端部の周面を非接触に覆うように磁石板２
０を設けて、磁石板１８の外側に漏れもしくは飛散した
現像剤が、さらに外部に行かないように磁力で拘束する
ことが行なわれる。Therefore, as a countermeasure, as shown in FIG. 9, the magnet plate 2 is provided outside the magnetic plate 18 so as to cover the peripheral surfaces of both ends of the developing sleeve 10 in a non-contact manner.
By providing 0, the developer that is leaked or scattered outside the magnet plate 18 is restrained by magnetic force so as not to go outside further.
【００１８】[0018]
【発明が解決しようとする課題】しかしながら、磁性板
１８の外側に配置された磁石板２０は、現像スリーブ１
０内のマグネットローラ８の磁極との相互作用が大き
く、現像スリーブ１０の両端部での磁気ブラシによる現
像剤の漏れや飛散の防止を安定して実現することができ
ない。However, the magnet plate 20 disposed outside the magnetic plate 18 is provided with the developing sleeve 1.
The interaction with the magnetic poles of the magnet roller 8 within 0 is large, and the leakage and scattering of the developer by the magnetic brushes at both ends of the developing sleeve 10 cannot be stably realized.
【００１９】つまり、マグネットローラ８の現像剤取り
込み極Ｎ3 の端部が位置した現像スリーブ１０の表面部
分と、磁石板２０の現像スリーブ１０と対向したＳ極の
内面部分の、磁極Ｎ3 に対応した部分との間に磁気ブラ
シが形成され、この磁気ブラシにより現像スリーブ１０
の端部において、現像スリーブ１０の回転により現像容
器２内に取り込まれくる現像剤が堰き止められ、滞留す
る。この新たな要因により、現像剤が現像容器２外に溢
れ出、また磁気ブラシの穂がばたついて現像剤が現像容
器２外に飛散する。In other words, the surface of the developing sleeve 10 where the end of the developer take-up pole N3 of the magnet roller 8 is located and the inner surface of the S pole of the magnet plate 20 facing the developing sleeve 10 correspond to the magnetic pole N3. A magnetic brush is formed between the developing sleeve 10 and the developing sleeve 10.
At the end, the developer taken into the developing container 2 by the rotation of the developing sleeve 10 is blocked and stays. Due to this new factor, the developer overflows outside the developing container 2, and the magnetic brush flaps and the developer scatters outside the developing container 2.
【００２０】さらに、現像容器２内から現像スリーブ１
０の端部に移送されてくる現像剤の漏れ、飛散について
も、次のように防止が完全でない。Further, the developing sleeve 1 is removed from the inside of the developing container 2.
The leakage or scattering of the developer transferred to the end of the zero is not completely prevented as follows.
【００２１】図１２、特に同図（ｂ）に示すように、現
像スリーブ１０の最端部での磁束密度の極性逆転（Ｎ極
→Ｓ極）が大きい場合には、磁石板２０を用いても、現
像スリーブ１０の軸方向（スラスト方向）の磁界が支配
的となり、反撥磁界領域の中心位置Ｒ近辺で、現像剤が
現像容器２外への漏れを生じる。If the polarity reversal (N pole → S pole) of the magnetic flux density at the extreme end of the developing sleeve 10 is large, as shown in FIG. Also, the magnetic field in the axial direction (thrust direction) of the developing sleeve 10 becomes dominant, and the developer leaks out of the developing container 2 near the center position R of the repelling magnetic field region.
【００２２】なお、図１２は、両端部に磁性板１８と磁
石板２０も配設せずに、現像スリーブ１０の表面の磁束
密度の軸方向上の分布を測定した結果で、図１２（ａ）
は磁極Ｎ3 の位置（Ｎ3 極位相）における磁束密度分
布、図１２（ｂ）は反撥磁界領域の中心位置Ｒ（Ｒ位
相）における磁束密度分布である。FIG. 12 shows the results of measuring the distribution of the magnetic flux density on the surface of the developing sleeve 10 in the axial direction without disposing the magnetic plate 18 and the magnet plate 20 at both ends. )
FIG. 12B shows the magnetic flux density distribution at the position of the magnetic pole N3 (N3 pole phase), and FIG. 12B shows the magnetic flux density distribution at the center position R (R phase) of the repelling magnetic field region.
【００２３】以上のようなことから、従来は、画像端部
にトナー汚れが発生したり、端部での帯電器汚れによる
異常放電で、画像にキャリア付着が発生したりして、長
期に亙って安定した画像を得ることは困難であった。ま
た、駆動ギヤや機内を汚し、機械の安定性を著しく低下
させてしまう問題もあった。As described above, conventionally, toner contamination occurs at the end of an image, and carrier adhesion occurs to an image due to abnormal discharge caused by contamination of a charger at the end. Therefore, it was difficult to obtain a stable image. There is also a problem that the drive gear and the inside of the machine are soiled, and the stability of the machine is significantly reduced.
【００２４】本発明の目的は、現像剤担持体の両端部に
設けた磁性板、磁石板および現像剤担持体内マグネット
ローラによる磁気ブラシにより、現像剤担持体の両端部
における磁性現像剤の漏れを確実にした防止した現像装
置を提供することである。An object of the present invention is to prevent leakage of magnetic developer at both ends of a developer carrying member by a magnetic plate provided at both ends of the developer carrying member, a magnetic plate and a magnetic brush formed by a magnet roller in the developer carrying member. An object of the present invention is to provide a developing device in which a reliable and prevented development is provided.
【００２５】[0025]
【課題を解決するための手段】上記目的は、本発明にか
かる現像装置にて達成される。要約すれば、本発明は、
磁性粒子を含む現像剤を収容した現像容器と、前記現像
剤を担持して回転する現像容器の開口部に配設された、
内側に磁界発生手段を非回転に配置した現像剤担持体
と、現像剤担持体の軸方向の各端部において現像剤担持
体の周面を非接触に囲む磁性部材と、前記各磁性部材の
外側で現像剤担持体の周面を非接触に囲む磁石板とを備
え、前記磁界発生手段は現像容器内の部分に反撥磁極を
有する現像装置において、前記磁石板の現像剤担持体と
対向する内面部分の、現像剤担持体軸方向に沿った磁極
構成は、前記反撥磁極のうちの一方の現像剤担持体回転
方向に関して上流側の磁極が位置した現像剤担持体の表
面部分と、前記磁石板のこれに対応した部分との間、お
よび前記現像剤担持体の軸方向最端部の表面部分と、前
記磁石板のこれに対応した部分との間に、現像剤の磁気
ブラシを形成しない磁極配置であることを特徴とする現
像装置である。The above object is achieved by a developing apparatus according to the present invention. In summary, the present invention provides:
A developing container containing a developer containing magnetic particles, and disposed at the opening of the developing container that rotates while carrying the developer,
A developer carrying member in which a magnetic field generating means is arranged non-rotatably on the inside, a magnetic member surrounding the peripheral surface of the developer carrying member in a non-contact manner at each axial end of the developer carrying member, and A magnet plate surrounding the peripheral surface of the developer carrier in a non-contact manner on the outside, wherein the magnetic field generating means faces the developer carrier of the magnet plate in a developing device having a repelling magnetic pole in a portion inside the developing container. The magnetic pole configuration of the inner surface portion along the developer carrier axis direction includes a surface portion of the developer carrier on which one of the repulsion magnetic poles is located on the upstream side with respect to the rotation direction of the developer carrier, and the magnet No magnetic brush of developer is formed between the corresponding portion of the plate, and between the axially outermost surface portion of the developer carrier and the corresponding portion of the magnet plate. A developing device having a magnetic pole arrangement.
【００２６】本発明によれば、前記磁石板の内面部分
の、前記現像剤担持体の軸方向最端部の表面部分に対応
した部分の磁極の極性が、前記上流側の磁極と同極性で
あり、前記磁石板の内面部分の、前記上流側の磁極の外
側の現像剤担持体の表面部分に対応した部分の磁極の極
性が、前記上流側の磁極と異極性であるとすることがで
きる。According to the present invention, the polarity of the magnetic pole at the portion corresponding to the axially outermost surface portion of the developer carrier on the inner surface of the magnet plate is the same as the polarity of the upstream magnetic pole. The polarity of the magnetic pole at the portion of the inner surface of the magnet plate corresponding to the surface portion of the developer carrier outside the magnetic pole on the upstream side may be different from the polarity of the magnetic pole on the upstream side. .
【００２７】また、前記磁石板の内面部分の、前記上流
側の磁極が位置した現像剤担持体の表面部分に対応した
部分が、前記上流側の磁極と同極性でかつ矩形の磁極に
形成され、前記磁石板の内面部分の残りの部分が、前記
上流側の磁極と異極性である。前記磁石板の内面部分
の、前記上流側の磁極が位置した現像剤担持体の表面部
分に対応した部分が、前記上流側の磁極と同極性でかつ
三角形の磁極に形成され、前記磁石板の内面部分の残り
の部分が、前記上流側の磁極と異極性であるとすること
ができる。A portion of the inner surface of the magnet plate corresponding to the surface portion of the developer carrier on which the upstream magnetic pole is located is formed as a rectangular magnetic pole having the same polarity as the upstream magnetic pole. The remaining portion of the inner surface portion of the magnet plate has a different polarity from the upstream magnetic pole. The portion of the inner surface of the magnet plate corresponding to the surface portion of the developer carrier on which the upstream magnetic pole is located is formed as a triangular magnetic pole having the same polarity as the upstream magnetic pole and the triangular magnetic pole. The remaining portion of the inner surface portion may be different in polarity from the magnetic pole on the upstream side.
【００２８】あるいは、前記磁石板の内面部分の、前記
上流側の磁極が位置した現像剤担持体の表面部分に対応
した部分を含む、前記現像剤担持体の周方向に沿った矩
形部分の全域が、前記上流側の磁極と同極性であり、前
記磁石板の内面部分の残りの矩形部分の全域が、前記上
流側の磁極と異極性であるとすることができる。Alternatively, the entire area of the rectangular portion along the circumferential direction of the developer carrying member, including the portion of the inner surface of the magnet plate corresponding to the surface portion of the developer carrying member on which the upstream magnetic pole is located May have the same polarity as the magnetic pole on the upstream side, and the entire area of the remaining rectangular portion of the inner surface of the magnet plate may have a different polarity from the magnetic pole on the upstream side.
【００２９】[0029]
【発明の実施の形態】以下、図面を参照して本発明の実
施例を詳細に説明する。Embodiments of the present invention will be described below in detail with reference to the drawings.
【００３０】図１は、本発明の現像装置の一実施例を示
す断面図、図２は、図１の現像装置の端部を示す断面図
である。FIG. 1 is a sectional view showing an embodiment of the developing device of the present invention, and FIG. 2 is a sectional view showing an end of the developing device of FIG.
【００３１】本発明の現像装置１は、カラー画像形成装
置に設けられるものである。本現像装置は、現像スリー
ブ１０の両端部に設置した磁石板の構成が、図８および
図９に示した従来の現像装置の場合と異なるので、本発
明では磁石板に符号２２を付与した。本現像装置のその
他の構成は従来と基本的に同じなので、図１〜２におい
て図８〜１１と同一の要素は同一の符号を付し、以下、
本現像装置の基本構成および作用を簡単に説明する。The developing device 1 of the present invention is provided in a color image forming apparatus. In the present developing device, the configuration of the magnet plates provided at both ends of the developing sleeve 10 is different from that of the conventional developing device shown in FIGS. 8 and 9. Other configurations of the present developing device are basically the same as those of the conventional developing device. Therefore, in FIGS. 1 and 2, the same elements as those in FIGS.
The basic configuration and operation of the developing device will be briefly described.
【００３２】本発明の現像装置１は、図示しない現像剤
を収容した現像容器２を備え、現像容器２内に配設され
たスクリュー４、６によって、現像剤が現像容器２内で
往復循環される。現像剤は磁性粒子を含む現像剤であ
り、樹脂中に磁性粒子を混練した磁性トナーからなる１
成分現像剤、または磁性粒子を主成分とする磁性キャリ
アと非磁性トナーを混合した２成分現像剤とされる。The developing device 1 of the present invention includes a developing container 2 containing a developer (not shown), and the developer is reciprocated in the developing container 2 by screws 4 and 6 disposed in the developing container 2. You. The developer is a developer containing magnetic particles, and is composed of a magnetic toner in which magnetic particles are kneaded in a resin.
It is a component developer or a two-component developer in which a magnetic carrier containing magnetic particles as a main component and a non-magnetic toner are mixed.
【００３３】現像装置１は、像担持体１００と対面した
開口部に現像スリーブ１０を有し、現像スリーブ１０
は、図２に示すように、その両端の軸１０ａを現像容器
２の両側の側壁２ａに軸受け１６を介して取り付けるこ
とにより、回転自在に支持されている。現像スリーブ１
０の内側にはマグネットローラ１２が設置され、その一
方の端部を図示しない軸部を側壁２ａに固定して、現像
スリーブ１０内に非回転に配置される。現像スリーブ１
０上の現像容器２の部分には、現像スリーブ１０と所定
の間隙を開けて磁性材料製の規制ブレード１４が設けら
れている。The developing device 1 has a developing sleeve 10 at an opening facing the image carrier 100.
As shown in FIG. 2, the shafts 10 a are rotatably supported by attaching shafts 10 a at both ends to side walls 2 a on both sides of the developing container 2 via bearings 16. Developing sleeve 1
A magnet roller 12 is provided inside the inside of the developing sleeve 10, and one end of the magnet roller 12 is fixed to a side wall 2 a with a shaft (not shown) so as to be non-rotatably disposed in the developing sleeve 10. Developing sleeve 1
A regulating blade 14 made of a magnetic material is provided at a part of the developing container 2 above the developing sleeve 10 with a predetermined gap from the developing sleeve 10.
【００３４】マグネットローラ１２は、その周囲に、現
像主極Ｓ１、同極の反撥磁極Ｎ3 、Ｎ2 を含む５つの磁
極Ｎ1 〜Ｎ3 、Ｓ1 〜Ｓ2 を有し、そのうちの現像主極
Ｓ１は、像担持体１００と現像スリーブ１０とが対向し
た現像部に位置し、反撥磁極Ｎ3 、Ｎ2 は、現像スリー
ブ１０の回転方向に関して現像部よりも下流の現像容器
２内に位置する。上流側の磁極Ｎ3 は現像剤取り込み
極、下流側の磁極Ｎ2 は現像剤汲み上げ極である。The magnet roller 12 has a main developing pole S1 and five magnetic poles N1 to N3 and S1 to S2 including the repulsive magnetic poles N3 and N2 of the same polarity around the main developing pole S1. The carrier 100 and the developing sleeve 10 are located in the developing section facing each other, and the repelling magnetic poles N3 and N2 are located in the developing container 2 downstream of the developing section in the rotation direction of the developing sleeve 10. The upstream magnetic pole N3 is a developer take-in pole, and the downstream magnetic pole N2 is a developer pumping pole.
【００３５】現像容器２内の現像剤は、現像スリーブ１
０の表面上に磁極Ｎ2 の作用により汲み上げられ、現像
スリーブ１０の回転にともない、磁極Ｓ2 →磁極Ｎ1 →
磁極Ｓ1 と搬送され、その途上で、規制ブレード１４に
より現像剤薄層に規制される。そして現像剤は、現像部
で磁極Ｓ1 の磁力により穂立ちして像担持体１００の表
面に接触し、像担持体１００上の静電潜像を現像し、つ
いで現像スリーブ１０の回転に従い現像容器２内に取り
込まれ、磁極Ｎ3 およびＮ2 による反撥磁界で現像スリ
ーブ１０上から剥離されて、現像容器２内に落下し回収
される。The developer in the developing container 2 is filled with the developing sleeve 1
The magnetic pole N2 is drawn by the action of the magnetic pole N2 on the surface of the developing sleeve 10, and the magnetic pole S2 → magnetic pole N1 →
It is conveyed to the magnetic pole S1, and is regulated by the regulating blade 14 to a thin layer of the developer on the way. Then, the developer rises due to the magnetic force of the magnetic pole S1 in the developing section and comes into contact with the surface of the image carrier 100 to develop the electrostatic latent image on the image carrier 100. 2 and is separated from the developing sleeve 10 by a repelling magnetic field generated by the magnetic poles N3 and N2, and falls into the developing container 2 to be collected.
【００３６】現像容器２内での循環移動によって、現像
剤が現像スリーブ１０の表面に沿って軸受け１６の部分
へ移送され、そこを通って容器２外へ漏れる。そこで、
図２に示すように、現像容器２の両側の各側壁２ａの内
面に、現像スリーブ１０の端部の周面を非接触に包囲す
る磁性板１８を取り付け、さらに磁性板１８の外側にお
いて、現像スリーブ１０の端部の周面を非接触に覆うよ
うに磁石板２２を設けている。これにより、磁性板１８
と現像スリーブ１０の表面の間に現像剤の磁気ブラシを
形成し、また磁石板２２と磁性板１８との間に現像剤の
磁気ブラシを形成している。Due to the circulating movement in the developing container 2, the developer is transferred along the surface of the developing sleeve 10 to the portion of the bearing 16, and leaks out of the container 2 therethrough. Therefore,
As shown in FIG. 2, a magnetic plate 18 surrounding the peripheral surface of the end portion of the developing sleeve 10 in a non-contact manner is attached to the inner surface of each side wall 2a on both sides of the developing container 2, and the developing plate is further provided outside the magnetic plate 18. The magnet plate 22 is provided so as to cover the peripheral surface of the end of the sleeve 10 in a non-contact manner. Thereby, the magnetic plate 18
A magnetic brush of the developer is formed between the magnetic plate 22 and the surface of the developing sleeve 10, and a magnetic brush of the developer is formed between the magnet plate 22 and the magnetic plate 18.
【００３７】しかしながら、前述したように、図９に示
した従来の磁石板２０の場合、現像スリーブ１０内のマ
グネットローラ８の磁極との相互作用が大きく、現像ス
リーブ１０の両端部での磁気ブラシによる現像剤漏れや
トナー飛散の防止を安定して実現することができなかっ
た。However, as described above, in the case of the conventional magnet plate 20 shown in FIG. 9, the interaction with the magnetic pole of the magnet roller 8 in the developing sleeve 10 is large, and the magnetic brushes at both ends of the developing sleeve 10 are used. Thus, it was impossible to stably prevent the developer from leaking and the toner from scattering.
【００３８】そこで、本発明では、図３（ａ）、（ｂ）
に示すように、磁石板２２の現像スリーブ１０に対向す
る内面部分の磁極構成を、マグネットローラ８の磁極Ｎ
3 に対向する部分ではＮ極、それ以外では全てＳ極であ
るように配置した。これにより、現像スリーブ１０の両
端部で現像剤が現像容器２の外側に漏れたり、トナーが
飛散することがなくなり、その結果、画質の安定性低下
の問題が全くなくなった。Therefore, in the present invention, FIGS. 3 (a) and 3 (b)
As shown in FIG. 3, the magnetic pole configuration of the inner surface of the magnet plate 22 facing the developing sleeve 10 is changed to the magnetic pole N of the magnet roller 8.
3 was arranged so as to be an N-pole at a portion opposed thereto and to an S-pole at all other portions. As a result, the developer does not leak to the outside of the developing container 2 at both ends of the developing sleeve 10 and the toner does not scatter, and as a result, the problem of deterioration in image quality stability is completely eliminated.
【００３９】以下、図４および図５を用いて説明する。Hereinafter, description will be made with reference to FIGS.
【００４０】まず、図４は、マグネットローラ８の磁極
Ｎ3 近傍の現像剤の様子を拡大して示すもので、図４
（ａ）は本発明の場合で、磁極Ｎ3 の対向部に磁石板２
２のＮ極を位置させてあり、図４（ｂ）は比較例の場合
で、磁極Ｎ3 の対向部に磁石板２２のＳ極を位置させて
ある。First, FIG. 4 is an enlarged view showing a state of the developer near the magnetic pole N3 of the magnet roller 8. FIG.
(A) shows the case of the present invention, in which the magnetic plate 2 is provided at a portion facing the magnetic pole N3.
FIG. 4B shows a comparative example, in which the S pole of the magnet plate 22 is located at a portion facing the magnetic pole N3.
【００４１】先の図１１から分かるように、マグネット
ローラ８の磁極Ｎ3 による現像スリーブ１０の表面の磁
力は、磁極Ｎ3 の端部に対応した部分近くまでＮ極を示
す。このため、図４（ｂ）の場合には、マグネットロー
ラ８の磁極Ｎ3 の端部が位置した現像スリーブ１０の表
面部分と、磁石板２２の現像スリーブ１０と対向したＳ
極の内面部分の、磁極Ｎ3 に対応した部分との間に磁気
ブラシが形成される。磁極Ｎ3 は、現像部を経て現像容
器２内に戻した現像剤の取り込み部に位置しており、現
像スリーブ１０の回転により現像容器２内に戻された現
像剤は、上記の磁石板２２のＳ極と磁極Ｎ3 による磁気
ブラシにより堰き止められるが、その内側には、現像ス
リーブ１０と磁性板１８との間に、磁性板１８とＮ3 極
による磁気ブラシが形成されているので、堰き止められ
た現像剤は、現像スリーブ１０の端部外側へはみ出し、
やがて軸受け１６の部分を通って現像容器２外に溢れ出
る。また磁極Ｎ3 と磁性板２２のＳ極による磁気ブラシ
は、現像スリーブ１０で搬送されてくる現像剤によりば
たつくので、現像容器２外へのトナーの飛散も生じる。As can be seen from FIG. 11, the magnetic force on the surface of the developing sleeve 10 due to the magnetic pole N3 of the magnet roller 8 indicates an N pole near the portion corresponding to the end of the magnetic pole N3. For this reason, in the case of FIG. 4B, the surface of the developing sleeve 10 where the end of the magnetic pole N3 of the magnet roller 8 is located, and the S
A magnetic brush is formed between the inner surface of the pole and a portion corresponding to the magnetic pole N3. The magnetic pole N3 is located at a portion where the developer returned to the developing container 2 via the developing portion is taken in. The developer returned to the developing container 2 by the rotation of the developing sleeve 10 The magnetic brush is formed by the S pole and the magnetic pole N3. However, the magnetic brush formed by the magnetic plate 18 and the N3 pole is formed between the developing sleeve 10 and the magnetic plate 18 inside the magnetic brush. The developing agent protrudes outside the end of the developing sleeve 10,
Eventually, the liquid will overflow the developing container 2 through the bearing 16. Further, the magnetic brush formed by the magnetic pole N3 and the S pole of the magnetic plate 22 fluctuates due to the developer conveyed by the developing sleeve 10, so that toner is scattered out of the developing container 2.
【００４２】これが、本実施例では、図４（ａ）のよう
に、磁石板２２の内面部分の磁極Ｎ3 と対向した部分の
磁極をＮ極としたので、Ｎ3 極およびＮ極からの磁力線
は反発しあって、現像スリーブ１０の表面と磁石板２２
との間で互に閉じる。このため、現像スリーブ１０の表
面と磁石板２２との間に磁気ブラシが形成されない部分
ができるので、現像スリーブ１０の端部で現像スリーブ
１０により搬送されて来る現像剤が堰き止められること
がなく、滞留することがない。In this embodiment, however, as shown in FIG. 4A, the magnetic pole at the portion facing the magnetic pole N3 on the inner surface of the magnet plate 22 is set to the N pole, so that the magnetic force lines from the N3 pole and the N pole are The surface of the developing sleeve 10 and the magnet plate 22
And close each other. For this reason, a portion where the magnetic brush is not formed is formed between the surface of the developing sleeve 10 and the magnet plate 22, so that the developer conveyed by the developing sleeve 10 at the end of the developing sleeve 10 is not blocked. , Does not stay.
【００４３】一方、磁石板２２の内面部分の磁極Ｎ3 と
Ｎ2 の反撥磁界領域の中心位置Ｒの部分には、現像容器
２の内側からの現像剤が溜まるが、磁極Ｎ3 のところで
は、上記したように、現像スリーブ１０と磁石板２２と
の間に磁気ブラシが形成されない部分があり、現像剤の
堰き止め、滞留がないので、現像スリーブ１０により現
像剤が搬送されてきても、磁極Ｎ3 の端部で現像剤が現
像容器２内に円滑に取り込まれる。従って、現像剤の漏
れや飛散がない。On the other hand, the developer from the inside of the developing container 2 accumulates at the central position R of the magnetic repulsion magnetic field region of the magnetic poles N3 and N2 on the inner surface of the magnet plate 22, but at the magnetic pole N3 as described above. As described above, there is a portion where the magnetic brush is not formed between the developing sleeve 10 and the magnet plate 22 and there is no damming or stagnation of the developer. Therefore, even if the developer is conveyed by the developing sleeve 10, At the end, the developer is smoothly taken into the developing container 2. Therefore, there is no leakage or scattering of the developer.
【００４４】つぎに、図５は、現像スリーブ１０の磁極
Ｎ3 よりも外側の部分、つまり最端部における現像剤の
様子を拡大して示すもので、図５（ａ）は本発明の場合
で、現像スリーブ１０の最端部に磁石板２２のＮ極を位
置させてあり、図５（ｂ）は比較例の場合で、最端部に
磁石板２２のＳ極を位置させてある。Next, FIG. 5 is an enlarged view showing the state of the developer at a portion outside the magnetic pole N3 of the developing sleeve 10, that is, at the outermost end, and FIG. 5A shows the case of the present invention. The north pole of the magnet plate 22 is located at the extreme end of the developing sleeve 10, and FIG. 5B is a comparative example in which the south pole of the magnet plate 22 is located at the extreme end.
【００４５】先の図１１から分かるように、現像スリー
ブ１０の最端部１０ｂの部分では、マグネットローラ１
０の磁極Ｎ3 の部分も、反撥磁界領域の中央位置Ｒの部
分も、極性がＳ極側に反転している。このため、図５
（ｂ）の場合には、現像スリーブ１０の最端部１０ｂの
表面部分と、これに対向した磁石板２２のＮ極の内面部
分との間に磁気ブラシが形成され、長期間の現像を行な
う間、この磁気ブラシの穂を伝わって、現像スリーブ最
端部１０ｂの外側まで現像剤が漏れ、前述したと同様な
問題が発生する。As can be seen from FIG. 11, the end portion 10b of the developing sleeve 10 has the magnet roller 1
The polarity of both the zero magnetic pole N3 and the central position R of the repelling magnetic field region is reversed to the S pole. For this reason, FIG.
In the case of (b), a magnetic brush is formed between the surface of the outermost end 10b of the developing sleeve 10 and the inner surface of the N pole of the magnet plate 22 opposed thereto, thereby performing long-term development. During this time, the developer leaks to the outside of the outermost end portion 10b of the developing sleeve through the ears of the magnetic brush, and the same problem as described above occurs.
【００４６】これが、本発明では、現像スリーブ１０の
最端部１０ｂに対応する磁性板１８の端部を、図３のよ
うに全てＳ極としているので、図５（ａ）に示すよう
に、磁石板２２のＳ極の内面部分の端部と、磁極Ｎ3 の
端部が位置した現像スリーブ１０の表面部分との間に磁
気ブラシは形成されるが、現像スリーブ１０の最端部１
０ｂまで延びる磁気ブラシは形成されない。その結果、
長期間の現像により、磁気ブラシの穂を伝わって、現像
スリーブ最端部１０ｂの外側まで現像剤が漏れる問題が
なくなる。In the present invention, since the ends of the magnetic plate 18 corresponding to the outermost end 10b of the developing sleeve 10 are all S poles as shown in FIG. 3, as shown in FIG. A magnetic brush is formed between the end of the inner surface of the south pole of the magnet plate 22 and the surface of the developing sleeve 10 where the end of the magnetic pole N3 is located.
No magnetic brush extending to 0b is formed. as a result,
By the long-term development, the problem that the developer leaks to the outside of the outermost end portion 10b of the developing sleeve through the ears of the magnetic brush is eliminated.
【００４７】以上の実施例では、磁石板２２には、たと
えばフェライト磁性粉とゴムとを練り合せたマグネット
材料を用いたが、弾力性に富むマグネット材料であれ
ば、これに限定されることはない。また磁石板２２は、
シート状のラバーマグネットとしたが、３００〜６００
ガウス程度の磁力が得られるように、適切な厚さ、寸
法、形状を選択することが好ましい。現像スリーブ１０
と磁石板２２の距離は、少なくとも磁石板２２上に穂立
ちした現像剤（磁気ブラシ）が、現像スリーブ１０の外
周面と軽く接触して、軽度にシールすることが可能な範
囲が良く、０．３〜２．０ｍｍの範囲で選択することが
好ましい。In the above embodiment, the magnet plate 22 is made of, for example, a magnet material obtained by kneading ferrite magnetic powder and rubber. However, the material is not limited to this as long as the magnet material is highly elastic. Absent. Also, the magnet plate 22
Sheet-shaped rubber magnet, but 300-600
It is preferable to select an appropriate thickness, size, and shape so that a magnetic force of about Gauss can be obtained. Developing sleeve 10
The distance between the magnetic plate 22 and the magnet plate 22 is preferably such that at least the developer (magnetic brush) raised on the magnet plate 22 can be lightly contacted with the outer peripheral surface of the developing sleeve 10 and lightly sealed. It is preferable to select in the range of 0.3 to 2.0 mm.
【００４８】さらに、磁石板２２は現像スリーブ１０の
周面全周にわたって配設してもよいが、図１に示すよう
に、現像容器２の範囲内で、少なくとも磁極Ｎ3 とＮ2
間の反撥磁界領域付近の磁性板１８による磁気ブラシの
形成が弱い領域に対向して、部分的に配設するだけでも
よく、十分な効果が得られる。Further, the magnet plate 22 may be disposed over the entire peripheral surface of the developing sleeve 10, but as shown in FIG. 1, at least the magnetic poles N 3 and N 2 within the developing container 2.
A sufficient effect can be obtained by only partially disposing a magnetic brush formed by the magnetic plate 18 in the vicinity of the magnetic repulsion magnetic field region therebetween.
【００４９】また磁石板２２は、図６に示すように、内
面部分のＮ極を現像スリーブ１０の周方向上の内側寄り
に細くした三角形に設けてもよい。これによれば、Ｎ極
とＳ極の境が斜めになり、現像スリーブ１０による現像
剤の搬送力が内側に向かうので、図３のときよりも、現
像剤を現像容器２外へ漏れにくくすることができる。Further, as shown in FIG. 6, the magnet plate 22 may be provided in a triangular shape in which the N pole on the inner surface is narrowed toward the inner side in the circumferential direction of the developing sleeve 10. According to this, the boundary between the N-pole and the S-pole becomes oblique, and the developer conveyance force by the developing sleeve 10 moves inward, so that the developer is less likely to leak out of the developing container 2 than in FIG. be able to.
【００５０】また、本発明では、磁石板２２の現像スリ
ーブ１０に対向した内面部分の磁極構成は、現像スリー
ブ１０の軸方向に沿った磁極構成が重要であり、マグネ
ットローラ８の磁極Ｎ3 が位置した現像スリーブ１０の
部分と磁石板２２との間で磁気ブラシを形成しないこ
と、磁極Ｎ3 の外側の現像スリーブ１０の最端部と磁石
板２２との間で磁気ブラシを形成しないことの２つの条
件を要件とする。従って磁石板２２は、たとえば図７に
示すように、矩形のＮ極とＳ極を現像スリーブ１０の軸
方向に横に並べ、Ｓ極の部分を現像スリーブ１０の最端
部の対応部としたものでもよい。In the present invention, it is important that the magnetic pole configuration of the inner surface of the magnet plate 22 facing the developing sleeve 10 is a magnetic pole configuration along the axial direction of the developing sleeve 10, and the magnetic pole N3 of the magnet roller 8 is located at the position. A magnetic brush is not formed between the portion of the developing sleeve 10 and the magnet plate 22; and a magnetic brush is not formed between the outermost end of the developing sleeve 10 outside the magnetic pole N3 and the magnet plate 22. Conditions are required. Therefore, as shown in FIG. 7, for example, the magnet plate 22 has rectangular N and S poles arranged side by side in the axial direction of the developing sleeve 10, and the S pole portion is a corresponding portion of the endmost portion of the developing sleeve 10. It may be something.
【００５１】[0051]
【発明の効果】以上説明したように、本発明によれば、
磁性粒子を含む現像剤を収容した現像容器の開口部に現
像剤担持体が配設され、その内側に非回転に配置した磁
界発生手段を有し、その磁界発生手段の現像容器内の部
分に反撥磁極を有する現像装置において、現像剤担持体
の両端部に、現像剤担持体の周面を非接触に囲む磁性部
材と、各磁性部材の外側で現像剤担持体の周面を非接触
に囲む磁石板とを設けて、これら磁性板、磁石板および
磁界発生手段による現像剤の磁気ブラシにより、現像剤
担持体の両端部をシールして、現像剤担持体の両端部で
の現像剤の現像容器外へ漏れおよび飛散を防止するに際
し、磁石板の現像剤担持体と対向する内面部分の、現像
剤担持体軸方向に沿った磁極構成を、反撥磁極のうちの
一方の現像剤担持体回転方向に関して上流側の磁極が位
置した現像剤担持体の表面部分と、前記磁石板のこれに
対応した部分との間、および現像剤担持体の軸方向の最
端部の表面部分と、磁石板のこれに対応した部分との間
に、現像剤の磁気ブラシを形成しない磁極配置としたの
で、現像剤担持体の両端部での現像剤の現像容器外へ漏
れおよび飛散を確実に防止することができる。As described above, according to the present invention,
A developer carrier is disposed at the opening of the developing container containing the developer containing the magnetic particles, and has a magnetic field generating means disposed non-rotatably inside the developing material carrier. In a developing device having a repelling magnetic pole, at both ends of the developer carrier, a magnetic member surrounding the peripheral surface of the developer carrier in a non-contact manner, and a peripheral surface of the developer carrier outside the respective magnetic members in a non-contact manner. An enclosing magnet plate is provided, and both ends of the developer carrier are sealed with the magnetic plate, the magnet plate and the magnetic brush of the developer by the magnetic field generating means, so that the developer at both ends of the developer carrier is sealed. When preventing leakage and scattering to the outside of the developing container, the magnetic pole configuration along the axial direction of the developer carrier of the inner surface portion of the magnet plate facing the developer carrier is changed to one of the repellent magnetic poles of the developer carrier. Developer loaded with the magnetic pole on the upstream side in the rotation direction Between the surface portion of the magnet plate and the corresponding portion of the magnet plate, and between the surface portion at the axial endmost portion of the developer carrier and the corresponding portion of the magnet plate. Since the magnetic poles are not formed, the leakage and scattering of the developer outside the developing container at both ends of the developer carrier can be reliably prevented.
【００５２】従って、画像端部にトナー汚れが発生した
り、端部での帯電器汚れによる異常放電で、画像にキャ
リア付着が発生することがなく、長期に亙って安定した
画像を得ることができ、また駆動ギヤや機内の汚れ、機
械の安定性低下も生じない。Accordingly, a stable image can be obtained for a long period of time without causing toner contamination on the image end portion or abnormal adhesion due to contamination of the charger at the end portion without causing carrier adhesion on the image. And no contamination of the drive gears and the inside of the machine, and no decrease in machine stability.
【図１】本発明の現像装置の一実施例を示す断面図であ
る。FIG. 1 is a sectional view showing one embodiment of a developing device of the present invention.
【図２】図１の現像装置の端部を示す断面図である。FIG. 2 is a sectional view showing an end of the developing device of FIG.
【図３】図１の現像装置の現像スリーブの各端部に設置
した磁性板および磁石板と、その磁石板の内面部分の磁
極構成を示す説明図である。FIG. 3 is an explanatory view showing a magnetic plate and a magnet plate installed at each end of a developing sleeve of the developing device of FIG. 1, and a magnetic pole configuration of an inner surface portion of the magnet plate.
【図４】図３の磁性板および磁石板を設けた現像スリー
ブのマグネットローラの磁極Ｎ3 近傍の現像剤の様子、
およびその磁石板を従来の磁石板に代えた場合の同様な
現像剤の様子を示す説明図である。FIG. 4 shows a state of a developer near a magnetic pole N3 of a magnet roller of a developing sleeve provided with the magnetic plate and the magnet plate of FIG. 3,
FIG. 9 is an explanatory view showing a state of a similar developer when the magnet plate is replaced with a conventional magnet plate.
【図５】図３の磁性板および磁石板を設けた現像スリー
ブのマグネットローラの磁極Ｎ3 よりも外側の最端部に
おける現像剤の様子、およびその磁石板を従来の磁石板
に代えた場合の同様な現像剤の様子を示す説明図であ
る。5 shows the state of the developer at the outermost end of the developing roller provided with the magnetic plate and the magnet plate of FIG. 3 outside the magnetic pole N3 of the magnet roller, and the case where the magnet plate is replaced with a conventional magnet plate; FIG. 4 is an explanatory diagram illustrating a similar state of a developer.
【図６】本発明で使用する磁石板の内面部分の他の磁極
構成例を示す斜視図である。FIG. 6 is a perspective view showing another example of the magnetic pole configuration of the inner surface portion of the magnet plate used in the present invention.
【図７】本発明で使用する磁石板の内面部分のさらに他
の磁極構成例を示す斜視図である。FIG. 7 is a perspective view showing still another example of the magnetic pole configuration of the inner surface portion of the magnet plate used in the present invention.
【図８】従来の現像装置を示す断面図である。FIG. 8 is a sectional view showing a conventional developing device.
【図９】図８の現像装置の端部を示す断面図である。FIG. 9 is a sectional view showing an end of the developing device of FIG. 8;
【図１０】図８の現像装置に設置された現像スリーブ表
面の磁束密度の周方向の分布を示す図である。FIG. 10 is a diagram illustrating a circumferential distribution of a magnetic flux density on the surface of a developing sleeve installed in the developing device of FIG. 8;
【図１１】図８の現像装置に設置された磁側板を配設し
た現像スリーブの表面の磁束密度の軸方向の分布を示す
図である。FIG. 11 is a diagram showing an axial distribution of a magnetic flux density on a surface of a developing sleeve provided with a magnetic side plate provided in the developing device of FIG. 8;
【図１２】図８の現像装置に設置された現像スリーブの
端部に磁側板を設置していないときの、現像スリーブ表
面の磁束密度の軸方向の分布を示す図である。12 is a diagram illustrating an axial distribution of a magnetic flux density on a surface of the developing sleeve when a magnetic side plate is not installed at an end of the developing sleeve installed in the developing device of FIG. 8;
１ 現像装置 ２ 現像容器 ２ａ 側壁 １０ 現像スリーブ １０ａ 軸 １０ｂ 現像スリーブの最端部 １２ マグネットローラ １６ 軸受け １８ 磁性板 ２２ 磁石板 DESCRIPTION OF SYMBOLS 1 Developing device 2 Developing container 2a Side wall 10 Developing sleeve 10a Shaft 10b End of developing sleeve 12 Magnet roller 16 Bearing 18 Magnetic plate 22 Magnet plate
Claims (5)
器と、前記現像剤を担持して回転する現像容器の開口部
に配設された、内側に磁界発生手段を非回転に配置した
現像剤担持体と、現像剤担持体の軸方向の各端部におい
て現像剤担持体の周面を非接触に囲む磁性部材と、前記
各磁性部材の外側で現像剤担持体の周面を非接触に囲む
磁石板とを備え、前記磁界発生手段は現像容器内の部分
に反撥磁極を有する現像装置において、前記磁石板の現
像剤担持体と対向する内面部分の、現像剤担持体軸方向
に沿った磁極構成は、前記反撥磁極のうちの一方の現像
剤担持体回転方向に関して上流側の磁極が位置した現像
剤担持体の表面部分と、前記磁石板のこれに対応した部
分との間、および前記現像剤担持体の軸方向の最端部分
の表面部分と、前記磁石板のこれに対応した部分との間
に、現像剤の磁気ブラシを形成しない磁極配置であるこ
とを特徴とする現像装置。A developing container containing a developer containing magnetic particles; and a developing device provided at an opening of a developing container which carries the developer and rotates, and a magnetic field generating means provided inside the developing container in a non-rotating manner. A magnetic member surrounding the peripheral surface of the developer carrier in a non-contact manner at each axial end of the developer carrier, and a non-contact peripheral surface of the developer carrier outside the magnetic member; Wherein the magnetic field generating means has a repelling magnetic pole at a portion inside the developing container, wherein the inner surface portion of the magnet plate facing the developer carrying member extends along the axial direction of the developer carrying member. The magnetic pole configuration is, between the surface portion of the developer carrier where the magnetic pole on the upstream side is located with respect to the direction of rotation of the developer carrier of one of the repulsive magnetic poles, between the corresponding portion of the magnet plate, and A surface portion of an axial endmost portion of the developer carrying member, A developing device having a magnetic pole arrangement in which a magnetic brush of developer is not formed between the magnet plate and a corresponding portion of the magnet plate.
磁極が位置した現像剤担持体の表面部分に対応した部分
の磁極の極性が、前記上流側の磁極と同極性であり、前
記磁石板の内面部分の、前記上流側の磁極の外側の現像
剤担持体の表面部分に対応した部分の磁極の極性が、前
記上流側の磁極と異極性である請求項１の現像装置。2. The magnetic pole of an inner surface portion of the magnet plate corresponding to a surface portion of the developer carrier on which the upstream magnetic pole is located has the same polarity as the upstream magnetic pole. The developing device according to claim 1, wherein a polarity of a magnetic pole of an inner surface portion of the magnet plate corresponding to a surface portion of the developer carrier outside the magnetic pole on the upstream side is different in polarity from the magnetic pole on the upstream side.
磁極が位置した現像剤担持体の表面部分に対応した部分
が、前記上流側の磁極と同極性でかつ矩形の磁極に形成
され、前記磁石板の内面部分の残りの部分が、前記上流
側の磁極と異極性である請求項１の現像装置。3. A portion of the inner surface of the magnet plate corresponding to the surface portion of the developer carrier where the upstream magnetic pole is located is formed as a rectangular magnetic pole having the same polarity as the upstream magnetic pole. 2. The developing device according to claim 1, wherein the remaining portion of the inner surface of the magnet plate has a different polarity from the magnetic pole on the upstream side.
磁極が位置した現像剤担持体の表面部分に対応した部分
が、前記上流側の磁極と同極性でかつ三角形の磁極に形
成され、前記磁石板の内面部分の残りの部分が、前記上
流側の磁極と異極性である請求項１の現像装置。4. A portion of the inner surface of the magnet plate corresponding to the surface portion of the developer carrier on which the upstream magnetic pole is located is formed as a triangular magnetic pole having the same polarity as the upstream magnetic pole. 2. The developing device according to claim 1, wherein the remaining portion of the inner surface of the magnet plate has a different polarity from the magnetic pole on the upstream side.
磁極が位置した現像剤担持体の表面部分に対応した部分
を含む、前記現像剤担持体の周方向に沿った矩形部分の
全域が、前記上流側の磁極と同極性であり、前記磁石板
の内面部分の残りの矩形部分の全域が、前記上流側の磁
極と異極性である請求項１の現像装置。5. A whole area of a rectangular portion along a circumferential direction of the developer carrier, including a portion of an inner surface portion of the magnet plate corresponding to a surface portion of the developer carrier on which the upstream magnetic pole is located. 2. The developing device according to claim 1, wherein the magnetic pole has the same polarity as the magnetic pole on the upstream side, and the entire area of the remaining rectangular portion on the inner surface of the magnet plate has a different polarity from the magnetic pole on the upstream side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22071197A JP3507294B2 (en) | 1997-08-01 | 1997-08-01 | Developing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22071197A JP3507294B2 (en) | 1997-08-01 | 1997-08-01 | Developing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1152731A true JPH1152731A (en) | 1999-02-26 |
| JP3507294B2 JP3507294B2 (en) | 2004-03-15 |
Family
ID=16755316
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22071197A Expired - Fee Related JP3507294B2 (en) | 1997-08-01 | 1997-08-01 | Developing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3507294B2 (en) |
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|---|---|---|---|---|
| JP2001356601A (en) * | 2000-05-18 | 2001-12-26 | Nexpress Solutions Llc | Developing station for printing device |
| JP2006071796A (en) * | 2004-08-31 | 2006-03-16 | Kyocera Mita Corp | Developing apparatus and image forming apparatus equipped with the same |
| JP2008116723A (en) * | 2006-11-06 | 2008-05-22 | Fuji Xerox Co Ltd | Developing device and image forming apparatus |
| JP2008164942A (en) * | 2006-12-28 | 2008-07-17 | Konica Minolta Business Technologies Inc | Developing device and image forming unit |
| JP2009031590A (en) * | 2007-07-27 | 2009-02-12 | Kyocera Mita Corp | Developing device and image forming apparatus equipped with the same |
| JP2009244611A (en) * | 2008-03-31 | 2009-10-22 | Ricoh Co Ltd | Developing device, image forming apparatus equipped with the same, and process cartridge |
| JP2011164366A (en) * | 2010-02-10 | 2011-08-25 | Ricoh Co Ltd | Developing device and image forming apparatus provided with the same and process cartridge |
| US8548361B2 (en) | 2011-07-11 | 2013-10-01 | Canon Kabushiki Kaisha | Developing device |
| US8811854B2 (en) | 2011-08-30 | 2014-08-19 | Canon Kabushiki Kaisha | Developing apparatus having a magnetic seal |
| US8874009B2 (en) | 2010-10-20 | 2014-10-28 | Canon Kabushiki Kaisha | Developing device having dual feeding chambers |
| WO2015178505A1 (en) * | 2014-05-23 | 2015-11-26 | キヤノン株式会社 | Developing device, process cartridge, and image forming device |
| US9383685B2 (en) | 2013-07-10 | 2016-07-05 | Canon Kabushiki Kaisha | Developing apparatus |
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1997
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Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001356601A (en) * | 2000-05-18 | 2001-12-26 | Nexpress Solutions Llc | Developing station for printing device |
| JP4684467B2 (en) * | 2000-05-18 | 2011-05-18 | イーストマン コダック カンパニー | Development station for printing equipment |
| JP2006071796A (en) * | 2004-08-31 | 2006-03-16 | Kyocera Mita Corp | Developing apparatus and image forming apparatus equipped with the same |
| JP4574284B2 (en) * | 2004-08-31 | 2010-11-04 | 京セラミタ株式会社 | Developing device and image forming apparatus having the same |
| JP2008116723A (en) * | 2006-11-06 | 2008-05-22 | Fuji Xerox Co Ltd | Developing device and image forming apparatus |
| JP2008164942A (en) * | 2006-12-28 | 2008-07-17 | Konica Minolta Business Technologies Inc | Developing device and image forming unit |
| JP2009031590A (en) * | 2007-07-27 | 2009-02-12 | Kyocera Mita Corp | Developing device and image forming apparatus equipped with the same |
| JP2009244611A (en) * | 2008-03-31 | 2009-10-22 | Ricoh Co Ltd | Developing device, image forming apparatus equipped with the same, and process cartridge |
| JP2011164366A (en) * | 2010-02-10 | 2011-08-25 | Ricoh Co Ltd | Developing device and image forming apparatus provided with the same and process cartridge |
| US8874009B2 (en) | 2010-10-20 | 2014-10-28 | Canon Kabushiki Kaisha | Developing device having dual feeding chambers |
| US8548361B2 (en) | 2011-07-11 | 2013-10-01 | Canon Kabushiki Kaisha | Developing device |
| US8811854B2 (en) | 2011-08-30 | 2014-08-19 | Canon Kabushiki Kaisha | Developing apparatus having a magnetic seal |
| US9383685B2 (en) | 2013-07-10 | 2016-07-05 | Canon Kabushiki Kaisha | Developing apparatus |
| WO2015178505A1 (en) * | 2014-05-23 | 2015-11-26 | キヤノン株式会社 | Developing device, process cartridge, and image forming device |
| JP2015222403A (en) * | 2014-05-23 | 2015-12-10 | キヤノン株式会社 | Developing apparatus, process cartridge, and image forming apparatus |
| CN106415403A (en) * | 2014-05-23 | 2017-02-15 | 佳能株式会社 | Developing device, process cartridge, and image forming device |
| US10248050B2 (en) | 2014-05-23 | 2019-04-02 | Canon Kabushiki Kaisha | Developing device having magnetic sealing members |
| US10739703B2 (en) | 2018-08-23 | 2020-08-11 | Canon Kabushiki Kaisha | Developing apparatus having magnetic field generating portion |
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| Publication number | Publication date |
|---|---|
| JP3507294B2 (en) | 2004-03-15 |
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