JPH087503B2 - Development device - Google Patents
Development deviceInfo
- Publication number
- JPH087503B2 JPH087503B2 JP1168750A JP16875089A JPH087503B2 JP H087503 B2 JPH087503 B2 JP H087503B2 JP 1168750 A JP1168750 A JP 1168750A JP 16875089 A JP16875089 A JP 16875089A JP H087503 B2 JPH087503 B2 JP H087503B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- developing
- developer
- sleeve
- image
- 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.)
- Expired - Lifetime
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- Magnetic Brush Developing In Electrophotography (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、電子写真複写機・電子写真式レーザビーム
プリンタ・LEDプリンタ・LCSプリンタ・マルチスタイラ
ス式静電プリンタ等の画像形成装置に於いて、像保持体
に形成された静電潜像を現像する現像装置に関する。The present invention relates to an image forming apparatus such as an electrophotographic copying machine, an electrophotographic laser beam printer, an LED printer, an LCS printer, and a multi-stylus electrostatic printer. , A developing device for developing an electrostatic latent image formed on an image carrier.
（従来の技術） 現像装置として、現像剤担持部材に担持された現像剤
の層厚を現像領域に於いて現像剤担持部材と像保持体と
の最小間隔よりも小として、像保持体に現像剤を飛翔さ
せて潜像を現像する方式の装置は公知である。(Prior Art) As a developing device, the layer thickness of the developer carried by the developer carrying member is set to be smaller than the minimum distance between the developer carrying member and the image carrying body in the developing area, and the developing is carried out on the image carrying body. An apparatus of a type in which a latent image is developed by flying an agent is known.
斯かる現像装置としては、内部に不動に位置固定され
た磁界発生部材（磁石）を有し、該磁界発生部材の外周
りを回動駆動される非磁性材製の現像剤担持部材を像保
持体に対向配設し、該現像剤担持部材面に現像剤を供給
して像保持体と対向する現像領域に担持・搬送させるこ
とにより像保持体面の潜像を現像する方式の現像装置が
多用されている。As such a developing device, there is a magnetic field generating member (magnet) that is fixedly fixed inside, and a non-magnetic material developer holding member that is rotationally driven around the magnetic field generating member holds an image. A developing device of a type that is disposed so as to face the body and develops the latent image on the surface of the image carrier by supplying the developer to the surface of the developer carrying member and carrying and carrying the developer in a developing area facing the image carrier is often used. Has been done.
本発明は上記のような方式・構成の現像装置の改良に
関するものである。The present invention relates to an improvement of the developing device having the above-described system and configuration.
（発明が解決しようとする課題） 従来、上記のような方式・構成の現像装置について改
良の望まれている問題点として下記のような事項があ
る。(Problems to be Solved by the Invention) Conventionally, there are the following matters as problems that are desired to be improved in the developing device having the above-described system and configuration.
（１） 顕画像の「尾引き」現象 第８図（Ａ）・（Ｂ）において（Ａ）図の100を良好
な顕画像（現像画像）の拡大パターンであるとすると、
このような顕画像に対して尾引き顕画像は（Ｂ）図の不
良顕画像の拡大パターン101のように被現像部材である
像保持体の移動方向ｄと逆方向に現像剤粒子（トナー）
が線状もしくは点状に連なり尾101Aを引いている状態と
なる現象である。(1) Phenomenon of "tailing" of a visible image If it is assumed that 100 in FIGS. 8A and 8B is a magnified pattern of a good visible image (developed image),
In contrast to such a visible image, the trailing visible image is a developer particle (toner) in a direction opposite to the moving direction d of the image carrier, which is the member to be developed, as in the enlarged pattern 101 of the defective visible image in FIG.
Is a phenomenon in which the tail 101A is drawn in a linear or dotted pattern.
（２） 「とびちり」現象 第８図（Ｂ）の101Bのように顕画像101の周辺又は周
囲に現像剤粒子が細かく飛び散った状態となる現象であ
る。(2) "Split" phenomenon This is a phenomenon in which the developer particles are finely scattered around or around the visible image 101 as shown by 101B in FIG. 8 (B).
上記のような現象は画像品位を低下させるもので、前
記のような方式・構成の従来の現像装置におおいて大な
り小なりみられる、或はあらわれやすい。特に現像剤と
して所謂一成分磁性現像剤を用いる系の現像装置にあっ
ては上記のような現象が顕著にあらわれやすい。The phenomenon as described above deteriorates the image quality, and is more or less significant or is likely to appear in the conventional developing device having the above-described system and configuration. In particular, in a developing device of a system that uses a so-called one-component magnetic developer as the developer, the above phenomenon is likely to appear remarkably.
本発明の目的は、前記従来技術に於ける問題点を解決
できる現像装置を提供することである。An object of the present invention is to provide a developing device capable of solving the above-mentioned problems in the prior art.
本発明の他の目的は、尾引き・飛び散り現象による画
像劣化を防止できる現像装置を提供することである。Another object of the present invention is to provide a developing device capable of preventing image deterioration due to the phenomenon of tailing / scattering.
本発明の更に他の目的は、潜像をより忠実に現像して
鮮明・高品位の現像画像を形成できる現像装置を提供す
ることである。Still another object of the present invention is to provide a developing device capable of more faithfully developing a latent image to form a clear and high-quality developed image.
（課題を解決するための手段） 本発明は下記の構成を特徴とする現像装置である。(Means for Solving the Problems) The present invention is a developing device having the following configuration.
（１） 静電潜像が形成される像保持体と対向して現像
領域を形成し、この現像領域に現像剤を搬送する現像剤
担持部材と、この現像剤担持部材内の現像領域と対向す
る位置に設けられた現像磁極と、を有する現像装置にお
いて、 現像剤担持部材表面の法線方向の磁束密度のピーク位
置が現像領域内に存在し、磁気拘束力のピーク位置は現
像領域の終端近傍に存在し、磁束密度のピーク位置から
像保持体の移動方向下流側にむかって磁気拘束力が大き
くなることを特徴とする現像装置。(1) A developer carrying member that forms a developing area facing the image carrier on which the electrostatic latent image is formed and conveys the developer to the developing area, and a developing area in the developer carrying member. In a developing device having a developing magnetic pole provided at a position where the magnetic flux density peaks in the normal direction of the surface of the developer carrying member exists in the developing area, the peak position of the magnetic binding force is the end of the developing area. A developing device which is present in the vicinity and has a large magnetic binding force from a peak position of magnetic flux density toward a downstream side in a moving direction of an image carrier.
（２） 上記磁束密度のピーク位置は現像領域の略中央
であることを特徴とする（１）に記載の現像装置。(2) The developing device according to (1), wherein the peak position of the magnetic flux density is substantially in the center of the developing area.
（３） 現像領域の始端近傍にも磁気拘束力のピーク位
置が存在することを特徴とする（１）もしくは（２）に
記載の現像装置。(3) The developing device according to (1) or (2), wherein a peak position of the magnetic restraining force exists near the starting end of the developing area.
（４） 法線方向の磁束密度のピークとゼロ間の角度と
ピークとピークの1/2の点間の角度の比は0.5以上である
ことを特徴とする（１）乃至（３）の何れか１つに記載
の現像装置。(4) The ratio of the angle between the peak and zero of the magnetic flux density in the normal direction and the angle between the peak and the half point of the peak is 0.5 or more, which is one of (1) to (3) The developing device according to one.
（作用） 一般に、現像剤担持部材から像保持体に現像剤粒子を
転移しやすくする為に、現像剤の磁気ブラシを現像剤担
持部材面に起立させる磁界を現像領域に形成し、これに
よって現像剤粒子を現像剤担持部材から離脱させやすく
している。このように現像剤粒子を現像剤担持部材から
離脱させやすくしていることが前記の尾引きや飛び散り
現象による画質劣化の主要な原因と思料される処、本発
明者は種々検討の結果、前記尾引きや飛び散り現象を惹
き起こす現像剤粒子の多くは、現像過程の後半以降で現
像剤担持部材から像保持体に転移してしまったものであ
ることを見出した。(Function) In general, in order to facilitate the transfer of the developer particles from the developer carrying member to the image carrier, a magnetic field that erects the magnetic brush of the developer on the surface of the developer carrying member is formed in the developing region, and thereby the development is performed. The developer particles are easily separated from the developer carrying member. It is considered that facilitating the separation of the developer particles from the developer carrying member in this manner is the main cause of the image quality deterioration due to the tailing and scattering phenomenon, and the present inventor has conducted various studies, It has been found that most of the developer particles that cause the tailing and scattering phenomenon are transferred from the developer carrying member to the image carrier in the latter half of the developing process.
そこで本発明では前記（１）乃至（４）のように、現
像剤担持部材面に対する法線方向の磁気拘束力を、像保
持体と現像剤担持部材の最近接位置、もしくは磁束密度
のピーク位置よりも、像保持体移動方向下流側で大であ
る。もしくは下流側及び上流側で大であるような磁界分
布態様にし、これによって現像剤粒子の尾引きや飛び散
り現象を惹き起こすような現像剤担持部材からの現像剤
粒子離脱を抑制し、また像保持体に尾引きや飛び散りと
して付着してしまった現像剤粒子を現像剤担持部材に戻
しやすくした。Therefore, in the present invention, as in the above (1) to (4), the magnetic restraining force in the direction normal to the surface of the developer carrying member is set to the closest position between the image carrier and the developer carrying member or the peak position of the magnetic flux density. Is larger on the downstream side in the moving direction of the image carrier. Alternatively, the magnetic field distribution is set to be large on the downstream side and the upstream side, thereby suppressing the separation of the developer particles from the developer carrying member which causes the trailing and scattering of the developer particles, and also the image holding. The developer particles that have adhered to the body as tails or splatters can be easily returned to the developer carrying member.
尚、上記法線方向についての磁気拘束力の現像剤担持
部材周方向についての分布形状は、磁気ブラシを現像剤
担持部材上に起立させるための上記法線方向についての
磁束密度の現像剤担持体周方向についての分布形状と相
似とはならない。The distribution shape of the magnetic restraining force in the circumferential direction of the developer carrying member in the normal direction is the developer carrying member of the magnetic flux density in the normal direction for standing the magnetic brush on the developer carrying member. It is not similar to the distribution shape in the circumferential direction.
上記において、磁気拘束力は垂直磁界により発生する
拘束力（磁界の２乗に関係する）と水平磁界により発生
する拘束力の合力であり、現像剤担持部材面に担持形成
される現像剤の磁気ブラシの形とは対称するものではな
い。In the above description, the magnetic restraining force is the resultant force of the restraining force generated by the vertical magnetic field (related to the square of the magnetic field) and the restraining force generated by the horizontal magnetic field, and is the magnetic force of the developer carried on the surface of the developer carrying member. It is not symmetrical to the brush shape.
より詳しい作用・考察は次の実施例の項において具体
例に基づいて述べる。More detailed action and consideration will be described based on a concrete example in the section of the next embodiment.
（実施例） 第５図は一成分磁性現像剤（キャリア粒子を含まず磁
性トナーを含む）を使用する現像装置である。(Embodiment) FIG. 5 shows a developing device using a one-component magnetic developer (containing magnetic toner but not carrier particles).
ドラム状電子写真感光体等の像保持体Ｂは矢示ｄ方向
に所定の周速度で回転駆動され、不図示の潜像形成工程
機器により目的画像に対応した静電潜像が周面に形成さ
れ、その形成潜像面が現像装置Ａにより順次にトナーで
顕画化される。顕画像は不図示の転写工程部で転写材面
に転写され、次いでその転写像が不図示の定着工程部で
転写材面に永久固着像として定着処理され、該転写材が
複写物（コピー）・記録物として出力される。The image carrier B such as a drum-shaped electrophotographic photosensitive member is rotationally driven in the direction of arrow d at a predetermined peripheral speed, and an electrostatic latent image corresponding to the target image is formed on the peripheral surface by a latent image forming process device (not shown). The formed latent image surface is sequentially visualized with toner by the developing device A. The visible image is transferred onto the surface of the transfer material in a transfer step (not shown), and then the transferred image is fixed as a permanently fixed image on the surface of the transfer material in a fixing step (not shown), and the transfer material is a copy. -It is output as a recorded matter.
現像装置Ａにおいて、１は現像剤収納容器、２は現像
剤担持部材としての現像スリーブ（円筒）であり、現像
剤収納容器１の前面側に左側のほぼ半周面を容器１外へ
露呈させ、右側のほぼ半周面を容器１内に入り込ませて
回転自由に横設してある。該現像スリーブ２はアルミニ
ウム・ステンレス（SUS）等の非磁性材製のもので、不
図示の動力伝達系から回転駆動力を受けてスリーブ２の
幾何学的中心線を軸として矢示Ｃ方向に所定の周速度で
回転駆動される。像保持体Ｂ面と現像スリーブ２の外部
露呈面は所定の僅小な間隔（最小間隔が50乃至1000μ
ｍ）を存して対向しており、その対向部が現像領域ａで
ある。In the developing device A, 1 is a developer accommodating container, 2 is a developing sleeve (cylindrical) as a developer carrying member, and a substantially semi-circular surface on the left side of the developer accommodating container 1 is exposed outside the container 1. The right half of the circumferential surface is inserted into the container 1 and laid freely rotatably. The developing sleeve 2 is made of a non-magnetic material such as aluminum and stainless steel (SUS), and receives a rotational driving force from a power transmission system (not shown) in the direction of arrow C with the geometric center line of the sleeve 2 as an axis. It is rotationally driven at a predetermined peripheral speed. The surface of the image carrier B and the externally exposed surface of the developing sleeve 2 have a predetermined small gap (the minimum gap is 50 to 1000 μm).
m), and the opposing portion is the developing area a.
現像領域ａに於いてスリーブ２から像保持体にトナー
が供給され、潜像が現像される。In the developing area a, toner is supplied from the sleeve 2 to the image carrier to develop the latent image.
３は現像スリーブ２の内空に挿入内蔵させた磁界発生
部材としてのマグネットローラである。このマグネット
ローラは非回転の不動ローラであり、現像スリーブ２は
このローラ３の外周りを回転駆動される。3a・3b・3c・
3dは該ローラ３の周囲の所定位置に磁極として設けた磁
石である。Reference numeral 3 denotes a magnet roller as a magnetic field generating member which is inserted and built in the inner space of the developing sleeve 2. The magnet roller is a non-rotating stationary roller, and the developing sleeve 2 is rotationally driven around the outer periphery of the roller 3. 3a / 3b / 3c /
3d is a magnet provided as a magnetic pole at a predetermined position around the roller 3.
磁石3aは現像極として現像領域部ａに対応位置してい
る。この磁極3aは現像領域ａに於いて現像剤の磁気ブラ
シをスリーブ２の表面に起立させる磁界を形成する。こ
の磁界の、スリーブ２の周面に対する法線方向の磁束密
度、即ち上記磁気ブラシをスリーブ２の表面に起立させ
る磁束密度のピークは領域ａ内にある。The magnet 3a is located at the developing area a as a developing pole. The magnetic pole 3a forms a magnetic field that causes the magnetic brush of the developer to stand on the surface of the sleeve 2 in the developing area a. The magnetic flux density of this magnetic field in the direction normal to the circumferential surface of the sleeve 2, that is, the peak of the magnetic flux density that causes the magnetic brush to stand on the surface of the sleeve 2 is within the region a.
磁石3bは現像剤規制極（カット極）として、現像スリ
ーブ２の上方に下辺エッジ部を現像スリーブ上面に所定
の僅小な間隔を存して対向させた現像剤層厚規制ブレー
ド４の下辺エッジ部に対応位置している。The magnet 3b serves as a developer regulating pole (cutting pole), and the lower edge of the developer layer thickness regulating blade 4 having the lower edge portion above the developing sleeve 2 opposed to the upper surface of the developing sleeve at a predetermined small interval. It is located corresponding to the department.
このブレード４は鉄等の磁性体であることが好まし
い。この場合、磁極3bの形成する磁界がブレード４に集
中し、この集中磁界によって磁性現像剤の薄層が形成さ
れる（特公昭59-8831号公報参照）。また現像剤の層厚
を規制する部材としては、スリーブ２に圧接された弾性
ブレードも使用できる（特公昭63-16736号公報参照）。This blade 4 is preferably made of a magnetic material such as iron. In this case, the magnetic field formed by the magnetic pole 3b is concentrated on the blade 4, and the concentrated magnetic field forms a thin layer of the magnetic developer (see Japanese Patent Publication No. 59-8831). An elastic blade pressed against the sleeve 2 can be used as a member for controlling the layer thickness of the developer (see Japanese Patent Publication No. 63-16736).
磁石3c・同3dは夫々現像剤搬送極として現像スリーブ
２の右側面側と下面側とに対応位置している。The magnets 3c and 3d are respectively located on the right side surface and the lower surface side of the developing sleeve 2 as developer carrying poles.
５は容器１内に収納された一成分磁性現像剤である。 Reference numeral 5 is a one-component magnetic developer housed in the container 1.
６・７は容器１内に配設され、夫々矢示方向に回転駆
動される現像剤攪拌棒と補助攪拌棒である。容器１内の
現像剤５は攪拌棒６の回転で十分な攪拌混合を受けると
共に、現像スリーブ２の右半周面側への寄せ搬送を受け
る。補助攪拌棒７は容器内奥側の現像剤を攪拌棒６側へ
寄せ搬送する。Denoted at 6 and 7 are a developer stirring rod and an auxiliary stirring rod, which are arranged in the container 1 and are rotationally driven in the directions indicated by the arrows. The developer 5 in the container 1 is sufficiently agitated and mixed by the rotation of the agitating rod 6, and is also conveyed to the right half circumferential surface side of the developing sleeve 2. The auxiliary stirring rod 7 moves the developer on the inner side of the container to the stirring rod 6 side and conveys it.
現像スリーブ２はその右側のほぼ半周面が常に容器１
内の現像剤５に接触して現像剤の供給を受け、現像スリ
ーブ面近傍の現像剤がスリーブ内部のマグネットロール
３の磁気力でスリーブ２面に磁気吸着層として付着担持
される。その担持現像剤層はスリーブ２の回転に伴ない
スリーブ２とブレード４との間を通ることにより層厚規
制を受けて均一な薄コート層として整層化され、その現
像剤薄コート層が引続くスリーブ２の回転で現像領域ａ
へ担持搬送されることにより、現像スリーブ２面側の担
持現像剤が像保持体Ｂ面側の潜像パターンに対応して像
保持体面へ移行付着し、像保持体Ｂ面が現像領域ａを通
過していくことにより潜像の顕画（現像）が順次に実行
されていく。The developing sleeve 2 always has a container 1 with a substantially semi-circular surface on the right side.
The developer in the vicinity of the surface of the developing sleeve is attached and carried on the surface of the sleeve 2 as a magnetic attraction layer by the magnetic force of the magnet roll 3 inside the sleeve, by contacting the developer 5 inside and receiving the supply of the developer. The carried developer layer is regulated as a uniform thin coat layer by passing between the sleeve 2 and the blade 4 as the sleeve 2 rotates, and is formed into a uniform thin coat layer. Subsequent rotation of the sleeve 2 causes development area a
By being carried to the surface of the developing sleeve 2, the carried developer on the surface of the developing sleeve 2 moves and adheres to the surface of the image carrier corresponding to the latent image pattern on the surface of the image carrier B, and the surface of the image carrier B moves to the developing area a. By passing, the latent image development (development) is sequentially executed.
現像剤層厚規制部材４は現像剤層の厚みが現像領域ａ
に於いてスリーブ２と像保持体Ｂの最小間隔よりも薄く
なるように現像剤層厚を規制する。In the developer layer thickness regulating member 4, the thickness of the developer layer is the development area a.
In this case, the developer layer thickness is regulated so as to be thinner than the minimum distance between the sleeve 2 and the image carrier B.
そしてスリーブ２には正弦波・短形波・三角波等の交
流電圧、又は交流電圧に直流電圧を重畳した電圧が電源
８から印加されており、これにより現像領域ａに交番電
界が形成される。An AC voltage such as a sine wave, a rectangular wave, or a triangular wave, or a voltage obtained by superimposing a DC voltage on an AC voltage is applied to the sleeve 2 from a power source 8, and an alternating electric field is formed in the developing area a.
上記交流電圧のピーク・トゥ・ピーク値（Vpp）は潜
像の最大電位と最小電位の差の絶対値より大であること
が好ましく、上記直流電圧の値（バイアス電圧の振動中
心値）は上記最大電位と最小電位の間の値であることが
好ましい。The peak-to-peak value (Vpp) of the AC voltage is preferably larger than the absolute value of the difference between the maximum potential and the minimum potential of the latent image, and the value of the DC voltage (the oscillation center value of the bias voltage) is the above. It is preferably a value between the maximum potential and the minimum potential.
そしてバイアス電圧の最大値・最小値は、前記潜像の
最大電位と最小電位の範囲内にあるのではなく、この範
囲の外にある値であることが好ましい。The maximum and minimum values of the bias voltage are preferably not within the range between the maximum potential and the minimum potential of the latent image but outside the range.
このようなバイアス電圧をスリーブ２に印加すること
によって、現像剤は現像領域ａに於いて振動運動し潜像
を現像する。交番電界によって現像剤は像保持体に付着
・離脱することを繰り返すが、最終的には像保持体には
潜像を電位に対応した量のトナーが付着残存する（特公
昭58-32377号公報参照）。By applying such a bias voltage to the sleeve 2, the developer vibrates in the developing area a and develops the latent image. The developer repeatedly attaches to and detaches from the image carrier by the alternating electric field, but finally, the toner corresponding to the potential of the latent image remains on the image carrier (Japanese Patent Publication No. 58-32377). reference).
尚、潜像の最大電位部にトナーを付着させて顕画化す
る正規現像に於いては潜像の電位極性と逆極性に帯電し
たトナーを使用する。潜像の最低電位部にトナーを付着
させて顕画化する反転現像に於いては潜像の電位極性と
同極性に帯電したトナーを使用する。一成分現像剤を使
用する場合、トナーはスリーブ２との摩擦で上記極性に
帯電する。Incidentally, in the normal development in which the toner is made visible by adhering the toner to the maximum potential portion of the latent image, the toner charged to the opposite polarity to the potential polarity of the latent image is used. In reversal development in which toner is made visible by attaching toner to the lowest potential portion of the latent image, toner charged to the same polarity as the potential polarity of the latent image is used. When a one-component developer is used, the toner is charged to the above polarity by friction with the sleeve 2.
上述のような交番電界はスリーブから現像剤を容易に
離脱させるので、前述の尾引き・飛び散り現象が発生し
やすい。一方、過剰に帯電したトナー、帯電量が不足し
たトナー、正規の極性と逆の極性に帯電したトナーは、
潜像の背景部に付着すると、交番電界によっても像保持
体から離脱しにくく、尾引き部や飛び散り部として残留
しやすい。本発明はこのような問題点の解決に効果があ
る。The alternating electric field as described above easily releases the developer from the sleeve, so that the above-mentioned tailing / scattering phenomenon easily occurs. On the other hand, excessively charged toner, insufficiently charged toner, and toner charged with a polarity opposite to the regular polarity are
When it adheres to the background portion of the latent image, it is difficult to separate from the image carrier even by an alternating electric field, and tends to remain as a tailing portion or a scattering portion. The present invention is effective in solving such problems.
いずれにせよ、現像に供されなかった残りの現像剤は
現像スリーブ２面に担持され、引続くスリーブの回転に
伴ない容器１内へ戻し搬送される。In any case, the remaining developer that has not been used for development is carried on the surface of the developing sleeve 2 and is returned and conveyed into the container 1 as the sleeve subsequently rotates.
像保持体Ｂ面の顕画像は次いで不図示の転写工程部を
通過することにより転写材面へ順次に転写される。The developed images on the surface of the image carrier B are then sequentially transferred to the transfer material surface by passing through a transfer process unit (not shown).
第６図はマグネットロール３の４つの固定磁極3a・3b
・3c・3dに対応したスリーブ表面上での磁束密度の、現
像スリーブ表面に対する法線方向の成分（法線方向磁束
密度）の分布を示している。即ち、9a・9b・9c・9dが夫
々現像極3a、カット極3b、搬送極3c、同3dの法線方向磁
束密度分布である。Ｑは０（ゼロ）ガウス線である。FIG. 6 shows four fixed magnetic poles 3a and 3b of the magnet roll 3.
The distribution of the magnetic flux density on the sleeve surface corresponding to 3c and 3d in the direction normal to the developing sleeve surface (normal direction magnetic flux density) is shown. That is, 9a, 9b, 9c, and 9d are magnetic flux density distributions in the normal direction of the developing pole 3a, the cutting pole 3b, the transporting pole 3c, and 3d, respectively. Q is a 0 (zero) Gaussian line.
分布9aは現像領域ａに於いて現像剤の磁気ブラシをス
リーブ表面上に起立させる法線方向磁束密度の分布であ
り、そのピークｅは領域ａ内にある。The distribution 9a is the distribution of the magnetic flux density in the normal direction that causes the magnetic brush of the developer to stand on the sleeve surface in the developing area a, and its peak e is in the area a.
第１図に現像領域ａ付近の法線方向磁束密度分布、及
びこの法線方向についての磁気拘束力の分布Ｆを示し
た。Ｑは上記磁束密度・磁気拘束力が０になる位置であ
る。上記磁気拘束力は現像剤粒子をスリーブ２の中心2a
の方向に磁気的に引き付ける力である。図示の如く磁気
拘束力のスリーブ円周方向についての分布形状と法線分
布磁束密度のスリーブ円周方向についての分布形状とは
相似形ではない。FIG. 1 shows a magnetic flux density distribution in the normal direction in the vicinity of the developing region a, and a magnetic binding force distribution F in the normal direction. Q is a position where the magnetic flux density and the magnetic binding force become zero. The magnetic binding force causes the developer particles to move to the center 2a of the sleeve 2.
Is a magnetically attractive force in the direction of. As shown in the figure, the distribution shape of the magnetic binding force in the sleeve circumferential direction and the distribution shape of the normal distribution magnetic flux density in the sleeve circumferential direction are not similar figures.
而して、上記磁気拘束力がスリーブ２と像保持体Ｂと
の最近接部（線ｂ上）に於けるよりも、像保持体移動方
向ｄに関して線ｂより下流側で大となる時、尾引き・飛
び散りのない良好な現像画像が得られた。Thus, when the magnetic restraining force is greater on the downstream side of the line b in the image carrier moving direction d than on the closest portion (on the line b) between the sleeve 2 and the image carrier B, A good developed image without tailing and scattering was obtained.
実施例で、前記磁気拘束力のスリーブ円周方向分布形
状が第１図のＦで示すような分布形状のとき、つまり磁
気拘束力が現像極3aの磁束密度9aのピーク位置ｅに於い
てよりも、現像領域ａの下流部側ｆにおいて強くなって
いる分布形状のとき、前述画像上の欠陥のない鮮明・高
品位の良好な画像が得られることを見出した。図示例で
は磁束密度9aのピーク位置ｅは像保持体Ｂの回動中心
（ドラムの幾何学的中心でもある）と現像スリーブ２の
中心軸線2aを結ぶ線ｂ上にある。In the embodiment, when the distribution shape of the magnetic binding force in the sleeve circumferential direction is as shown by F in FIG. 1, that is, the magnetic binding force is more at the peak position e of the magnetic flux density 9a of the developing pole 3a. It was also found that when the distribution shape is stronger on the downstream side f of the developing area a, a clear and high-quality image free of defects on the image can be obtained. In the illustrated example, the peak position e of the magnetic flux density 9a is on the line b connecting the center of rotation of the image carrier B (which is also the geometric center of the drum) and the central axis 2a of the developing sleeve 2.
第９図は従来例のこの種現像装置についての現像領域
部ａにおける法線方向磁気拘束力のスリーブ周方向分布
形状Ｆ′の例を示している。FIG. 9 shows an example of the sleeve circumferential direction distribution shape F'of the magnetic restraining force in the normal direction in the developing area a in this type of developing device of the prior art.
第９図の磁気拘束力パターンを有するマグネツトロー
ルを用いた場合には尾引き・飛び散りのある画像（第８
図（Ｂ））をみやすかった。In the case of using the magnetroll having the magnetic restraint force pattern shown in FIG.
It was easy to see the figure (B)).
このように現像極3aの法線方向磁束密度9aのピーク位
置ｅに対し、像保持体移動方向に関するその下流側にお
いて法線方向磁気拘束力がピーク位置ｅに於ける拘束力
より大きくなっていると、尾引き・飛び散りのない鮮鋭
な画像が常に安定に得られることがわかった。このこと
は、一成分磁性現像剤の１つ１つの粒子に働くスリーブ
表面に対する法線方向の力が上記条件を満していると
き、尾引き・飛び散りのない鮮鋭な画像が得られること
を意味している。Thus, with respect to the peak position e of the magnetic flux density 9a in the normal direction of the developing pole 3a, the magnetic force in the normal direction in the downstream side in the moving direction of the image carrier is larger than the binding force in the peak position e. It was found that a sharp image with no trailing or splattering is always stable. This means that when the force in the direction of the normal to the sleeve surface acting on each particle of the one-component magnetic developer satisfies the above conditions, a sharp image without tailing or scattering can be obtained. are doing.
第１図のような法線方向磁気拘束力分布形状Ｆを有す
るときは、現像領域ａにて像保持体Ｂと現像スリーブ２
の最近接位置より下流側ｆに於いて、法線方向の磁気拘
束力が大きくなっている為、現像剤は該下流側ｆにてよ
り強く現像スリーブ２側に引き戻される力を受ける。そ
の結果、現像領域ａの下流側ｆでは、現像磁極部3aによ
り形成された現像剤の穂がすぐに現像スリーブ２側に引
きつけられる。従って、尾引きや飛び散りのもととなる
余計な現像剤が像保持体Ｂ面側に行きにくくなっている
と考えられる。又一方、現像領域ａの像保持体Ｂと現像
スリーブ２との最近接点より上流側において尾引きや飛
び散りのもととなる余計に像保持体に付着した現像剤が
上記磁気拘束力により現像スリーブ側に引き戻され、尾
引き・飛び散りがなくなると考えられる。When the magnetic binding force distribution shape F in the normal direction as shown in FIG. 1 is present, the image holding member B and the developing sleeve 2 in the developing area a.
Since the magnetic restraining force in the normal direction is larger on the downstream side f than the closest position to the developer, the developer receives a stronger force to be returned to the developing sleeve 2 side on the downstream side f. As a result, on the downstream side f of the developing area a, the ears of the developer formed by the developing magnetic pole portion 3a are immediately attracted to the developing sleeve 2 side. Therefore, it is considered that the extra developer that causes tailing and splattering does not easily reach the surface of the image carrier B. On the other hand, on the upstream side of the closest contact point between the image holding member B and the developing sleeve 2 in the developing area a, the developer attached to the image holding member excessively, which causes tailing and scattering, is generated by the magnetic binding force. It is thought that it will be pulled back to the side and there will be no trailing or scattering.
以上は、現像磁極3aの方線方向磁束密度のピーク位置
ｅが、回動する像保持体Ｂの中心と現像スリーブ２の中
心を結ぶ線ｂ上にある場合について述べたが、該ピーク
位置ｅを現像領域ａ内で、線ｂの上流側・下流側に若干
ずらして使う場合についても同様にあてはまる。つま
り、法線方向磁気拘束力Ｆが、回動する像保持体Ｂの中
心と現像スリーブ２の中心を結ぶ線ｂ、つまり像保持体
と現像スリーブの最近接点より下流側に於いて大きくな
っている条件を満たすとき尾引きや飛び散りのない鮮鋭
な顕画像が安定に得られる。The case has been described above where the peak position e of the magnetic flux density in the direction of the developing magnetic pole 3a is on the line b connecting the center of the rotating image carrier B and the center of the developing sleeve 2. The peak position e The same applies to the case where is used in the developing area a with a slight shift to the upstream side / downstream side of the line b. That is, the magnetic force F in the normal direction becomes larger on the line b connecting the center of the rotating image carrier B and the center of the developing sleeve 2, that is, on the downstream side than the closest contact point of the image carrier and the developing sleeve. When the condition is satisfied, a sharp visible image without tailing or scattering can be stably obtained.
次に、更に改良した例について述べる。 Next, a further improved example will be described.
第２図で、法線方向磁気拘束力Ｆは像保持体とスリー
ブの最近接部、即ち線ｂの位置に於いてよりも、像保持
体移動方向に関して線ｂの位置より上流側及び下流側で
夫々大きくなっている。In FIG. 2, the magnetic force F in the normal direction is the upstream side and the downstream side of the position of line b with respect to the moving direction of the image carrier, rather than at the closest position of the image carrier and the sleeve, that is, at the position of line b. And they are getting bigger.
現像領域ａ近傍の磁気拘束力分布が第２図の実線Ｆの
ような形状であるときは、現像開始域近傍での磁気拘束
力が強くなっているので、像保持体Ｂ面上に移動しよう
とする現像スリーブ２側に担持されている一成分磁性現
像剤の動きが該磁気拘束力により規制され、必要以上の
現像剤が像保持体Ｂ側に付着することがなくなる。つま
り、尾引きや飛び散りの原因となる必要以上の現像剤の
像保持体Ｂ面側への以降付着を規制する作用をする。When the magnetic binding force distribution in the vicinity of the development area a has a shape as shown by the solid line F in FIG. 2, the magnetic binding force in the vicinity of the development start area is strong, so move to the surface of the image carrier B. The movement of the one-component magnetic developer carried on the side of the developing sleeve 2 is regulated by the magnetic restraining force, and the unnecessary amount of developer does not adhere to the image carrier B side. In other words, it has a function of restricting the excessive adhesion of the excessive amount of developer, which causes tailing and scattering, to the surface of the image carrier B.
また、現像終了域近傍においても、磁気拘束力が強く
なっている為、像保持体Ｂ面上に必要以上に付着してい
る現像剤を現像スリーブ２面側へ引き戻す作用がある。
その結果、尾引きや飛び散りのない、従って潜像即ち原
稿に忠実な鮮明な高品位画像が得られることになる。Further, since the magnetic binding force is strong even in the vicinity of the developing end area, there is an action of pulling back the developer adhering more than necessary on the surface of the image carrier B to the surface of the developing sleeve 2.
As a result, it is possible to obtain a clear high-quality image without tailing or splattering, and thus with a latent image, that is, a document faithful to the original.
一方、現像領域ａの中央部近傍（線ｂの近傍）におい
ても磁気拘束力が強すぎると、現像剤に対する規制が強
くなりすぎ、画像濃度が薄くなってしまうことがある。
従って、該現像領域中央部近傍においては、現像開始域
近傍および現像終了域近傍における磁気拘束力よりも低
い磁気拘束力になっていることが好ましい。On the other hand, if the magnetic binding force is too strong even in the vicinity of the central portion of the development area a (in the vicinity of the line b), the restriction on the developer may become too strong, and the image density may become low.
Therefore, it is preferable that the magnetic binding force in the vicinity of the central portion of the developing area is lower than the magnetic binding force in the vicinity of the developing start area and in the vicinity of the developing end area.
特に該磁気拘束力のスリーブ周方向分布形状Ｆが像保
持体Ｂと現像剤担持部材としての現像スリーブ２との最
近接部を結ぶ線ｂに関してほぼ対称をなしているとき最
も好ましい効果が得られた。In particular, the most preferable effect can be obtained when the sleeve circumferential distribution shape F of the magnetic restraining force is substantially symmetrical with respect to the line b connecting the closest portion between the image carrier B and the developing sleeve 2 as the developer carrying member. It was
もっとも、方線方向磁気拘束力のスリーブ周方向分布
形状Ｆが第３図例のように線ｂに対し対称になっていな
い場合でも、ｂ線の位置よりも、ｂ線の上流側と下流側
で磁気拘束力が大きくなっていれば、尾引きや飛び散り
現象による画像劣化防止効果がある。However, even when the sleeve circumferential distribution shape F of the magnetic force in the direction of the direction is not symmetrical with respect to the line b as in the example of FIG. 3, the upstream side and the downstream side of the b line from the position of the b line. If the magnetic restraining force is large, there is an effect of preventing image deterioration due to tailing and scattering phenomenon.
第２図・第３図に於いては、法線方向磁束密度9aのピ
ークｅが線ｂ上に位置しているが、このピークｅは現像
領域ａ内であれば線ｂよりも若干上流側又は下流側にず
れた位置に設定してもよい。In FIGS. 2 and 3, the peak e of the magnetic flux density 9a in the normal direction is located on the line b, but this peak e is slightly upstream of the line b in the developing area a. Alternatively, it may be set at a position shifted to the downstream side.
いずれにせよ、この磁束密度ピークｅの位置での磁気
拘束力よりも、像保持体移動方向に関してピークｅ位置
の上流側、下流側で磁気拘束力が強くなっている。In any case, the magnetic restraint force is stronger on the upstream side and the downstream side of the peak e position in the image carrier moving direction than the magnetic restraint force at the position of the magnetic flux density peak e.
第１・２・３図に於いて、線ｂよりも下流側の磁気拘
束力のピークｇの位置は、現像領域の終端a2の近傍の位
置にあることが望ましい。即ち、線ｂからa2点までの距
離をl2とすると、ピークｇはa2点から像保持体移動方向
に関して上流側と下流側に夫々l2Ｘ（1/3）の距離の範
囲に設定することが望ましい。In FIGS. 1, 2, and 3, it is desirable that the position of the peak g of the magnetic binding force on the downstream side of the line b is near the end a 2 of the developing area. That is, assuming that the distance from the line b to the point a 2 is l 2 , the peak g is in the range of distance l 2 X (1/3) from the point a 2 to the upstream side and the downstream side with respect to the moving direction of the image carrier. It is desirable to set.
また、第２・３図に於いて、線ｂよりも上流側の磁気
拘束力のピークｈの位置は現像領域の始端a1の近傍にあ
ることが望ましい。Further, in FIGS. 2 and 3, it is desirable that the position of the peak h of the magnetic binding force on the upstream side of the line b is near the starting end a 1 of the developing area.
即ち線ｂからa1点までの距離をl1とすると、ピークｈ
はa1点から像保持体移動方向に関し上流側と下流側に夫
々l1Ｘ（1/3）の距離の範囲に設定することが望まし
い。That is, if the distance from the line b to the point a 1 is l 1 , the peak h
Is preferably set within a range of a distance of l 1 X (1/3) from the point a 1 to the upstream side and the downstream side in the moving direction of the image carrier.
尚、第１・２・３図のように、法線方向磁束密度のピ
ークｅの位置よりも像保持体移動方向に関して下流側で
磁気拘束力がピークｇを有するような磁界を形成するに
は、法線方向磁束密度分布がW2＝β2／α2が0.5以上で
あるような分布であることが必要である。また、第２・
３図のように法線方向磁束密度のピークｅの位置よりも
像保持体移動方向に関して上流側で磁気拘束力がピーク
ｈを有するような磁界を形成するには、法線方向磁束密
度分布がW1＝β1／α1が0.5以上であるような分布であ
ることが必要である。W1・W2は夫々0.65以上であること
がより好ましい。Incidentally, as shown in FIGS. 1, 2 and 3, in order to form a magnetic field having a magnetic binding force having a peak g on the downstream side in the moving direction of the image carrier with respect to the position of the peak e of the magnetic flux density in the normal direction, The distribution of the magnetic flux density in the normal direction must be such that W 2 = β 2 / α 2 is 0.5 or more. Also, the second
As shown in FIG. 3, in order to form a magnetic field in which the magnetic binding force has a peak h on the upstream side of the position of the peak e of the magnetic flux density in the normal direction in the moving direction of the image carrier, the magnetic flux density distribution in the normal direction is It is necessary that the distribution is such that W 1 = β 1 / α 1 is 0.5 or more. It is more preferable that W 1 and W 2 are respectively 0.65 or more.
α1・α2・β1・β2はスリーブの回転中心から見た角
度である。第４図に示すようにα1はｉ点・ｅ点間の角
度、α2はｅ点・ｊ点間の角度、β1はｋ点・ｅ点間の角
度、β2はｅ点・ｌ点間の角度である。そしてｉ点はｅ
点に対し像保持体移動方向に関して上流側で法線方向磁
束密度9aが０になる点であり、ｊ点はｅ点に対し像保持
体移動方向下流側で法線方向磁束密度9aが０になる点で
ある。またｋ点・ｌ点は夫々法線方向磁束密度9aがピー
ク点ｅのそれの1/2となる点である。α 1 · α 2 · β 1 · β 2 are the angles seen from the rotation center of the sleeve. As shown in FIG. 4, α 1 is the angle between the points i and e, α 2 is the angle between the points e and j, β 1 is the angle between the points k and e, and β 2 is the point e / l. The angle between the points. And the point i is e
The point 9 is a point where the magnetic flux density 9a in the normal direction becomes 0 on the upstream side with respect to the moving direction of the image carrier with respect to the point, and the point j is 0 for the magnetic flux density 9a in the normal direction on the downstream side in the moving direction of the image carrier with respect to the point e. That is the point. The points k and l are points at which the magnetic flux density 9a in the normal direction is half that of the peak point e.
尚、以上の実施例では、スリーブ２は像保持体Ｂと領
域ａに於いて同方向に回転しているが、逆方向に回転し
てもよい。またスリーブ２と像保持体Ｂの周速比は所望
の現像画像濃度が得られるように任意に設定できる。Although the sleeve 2 rotates in the same direction as the image carrier B in the area a in the above embodiment, it may rotate in the opposite direction. Further, the peripheral speed ratio between the sleeve 2 and the image carrier B can be arbitrarily set so that a desired developed image density can be obtained.
前述の磁束密度分布・磁気拘束力分布を得るには、複
数のマグネットを夫々適宜の方向付けをして貼り合せた
り、ローラ状の磁性体に適宜のパターンで着磁したり、
或はこのようにして形成された磁石体の一部を削った
り、溝を入れたりする等の方法で実現できる。いずれに
せよ、磁気拘束力の分布形状は、磁束密度の分布形状に
依存すると考えられる。In order to obtain the above-mentioned magnetic flux density distribution / magnetic restraining force distribution, a plurality of magnets are appropriately oriented and bonded together, or magnetized in a suitable pattern on a roller-shaped magnetic body,
Alternatively, it can be realized by a method such as cutting a part of the magnet body formed in this way or forming a groove. In any case, it is considered that the distribution shape of the magnetic binding force depends on the distribution shape of the magnetic flux density.
また、磁性キャリアと非磁性トナーを含む２成分現像
剤を使用し、この現像剤の層を像保持体とスリーブとの
最小間隔よりも薄い層に形成して所謂非接触現像する現
像装置にも本発明は適用できる。この場合も現像領域に
は前述の如き交番電界が形成される。而して本発明を適
用すれば磁性キャリア粒子の挙動が好適に規制され、尾
引きや飛び散り現象を惹き起こするトナー量を低減でき
る。Also, a two-component developer containing a magnetic carrier and a non-magnetic toner is used, and a layer of this developer is formed in a layer thinner than the minimum gap between the image carrier and the sleeve, so-called non-contact developing device. The present invention can be applied. Also in this case, the alternating electric field as described above is formed in the developing area. Thus, by applying the present invention, the behavior of the magnetic carrier particles is suitably controlled, and the amount of toner that causes tailing or scattering phenomenon can be reduced.
第７図（Ａ）・（Ｂ）は磁気拘束力の測定法説明図で
ある。現像スリーブ２に近接して微小磁性体球10が配設
されている。該磁性体球10は非磁性体製の細いシャフト
11に固定されており、該シャフト11は現像スリーブ２の
回転軸を通る鉛直線上に配設されている。また該シャフ
ト11の他端は荷重変換器（ストレインゲージ）12に固定
接続されており、磁性体球10が現像スリーブ２内の磁界
発生部材３の磁界作用で受ける磁気的拘束力のうちスリ
ーブ表面に対する法線方向の成分力にのみ感応するよう
に調整されている。現像スリーブ２の内部には、前述の
固定磁石3a・3b・3c・3dがスリーブ２と同軸に回動可能
に配設されている。磁気拘束力のスリーブ周方向分布の
測定はスリーブ２と同軸に回動可能に配設された該固定
磁石を回動させることにより行う。荷重変換器12からの
出力はブリッジ13を介して増幅器14に接続される。ま
た、増幅器14は記録計15と接続されており垂直方向磁気
拘束力に応じた出力の周方向分布が記録できる。FIGS. 7 (A) and 7 (B) are explanatory views of a method for measuring the magnetic binding force. A minute magnetic material sphere 10 is arranged near the developing sleeve 2. The magnetic ball 10 is a thin shaft made of non-magnetic material.
It is fixed to 11, and the shaft 11 is arranged on a vertical line passing through the rotation axis of the developing sleeve 2. The other end of the shaft 11 is fixedly connected to a load transducer (strain gauge) 12, and the magnetic surface of the magnetic ball 10 is affected by the magnetic field action of the magnetic field generating member 3 in the developing sleeve 2. It is adjusted so that it is sensitive only to the component force in the normal direction to. Inside the developing sleeve 2, the above-mentioned fixed magnets 3a, 3b, 3c, 3d are arranged so as to be rotatable coaxially with the sleeve 2. The distribution of the magnetic restraining force in the sleeve circumferential direction is measured by rotating the fixed magnet that is rotatably arranged coaxially with the sleeve 2. The output from the weight converter 12 is connected to the amplifier 14 via the bridge 13. Further, the amplifier 14 is connected to the recorder 15 and can record the circumferential distribution of the output according to the vertical magnetic binding force.
実際の測定では磁性体球10としてフェライトの直径約
1mmの球状のものを用い、シャフト11としてはステンレ
ス綱の1mmφの丸棒を用いた（非磁性部材なら何でもよ
い）。磁性体球10とスリーブ２との間隔距離は約0.5mm
とした。また荷重変換器12は共和電業社製・型番120T-5
B、増幅器14は同社製・型番DPM-305A、記録計15はグラ
フテク社製・XY-PLOTTER、FP5301Rを用いた。In actual measurement, the diameter of the ferrite is about 10
A 1 mm spherical shape was used, and a 1 mmφ round rod made of stainless steel was used as the shaft 11 (any non-magnetic member may be used). The distance between the magnetic ball 10 and the sleeve 2 is about 0.5 mm
And The load converter 12 is a model number 120T-5 manufactured by Kyowa Denki Co., Ltd.
B, the amplifier 14 was manufactured by the same company, model number DPM-305A, and the recorder 15 was Graphtech's XY-PLOTTER, FP5301R.
第１・２・３・９図の、現像極近傍における法線方向
の磁気拘束力の周方向分布形状Ｆ・Ｆ′は上記の測定法
により求めたものである。The circumferential distribution shape F · F ′ of the magnetic binding force in the normal direction in the vicinity of the developing pole in FIGS. 1, 2, 3, and 9 is obtained by the above-described measuring method.
なお、磁性体球10としては現像剤たる実際のトナー粒
子を使うのが最善ではあるが、実際のトナー粒子では直
径が10μｍ前後で小さく、そのトナーが受ける力も微弱
である為、現時点では荷重変換器12として充分な感度を
有するものがなく実測は難しい。Although it is best to use actual toner particles as a developer as the magnetic balls 10, the actual toner particles have a small diameter of around 10 μm, and the toner receives a weak force. It is difficult to measure because there is no device with sufficient sensitivity as the container 12.
また本測定方法では、磁性体球10と現像スリーブ２と
の距離により出力値は変化するが、該距離を０〜2mm程
度変化させてもそのスリーブ周方向分布はほぼ相似形で
ある。In this measuring method, the output value changes depending on the distance between the magnetic ball 10 and the developing sleeve 2. Even if the distance is changed by about 0 to 2 mm, the sleeve circumferential distribution is almost similar.
上記の距離範囲において、距離0mmは、現像スリーブ
を外し内部のマグネットをむき出しの状態にて測定を行
なうものである。In the above distance range, the distance of 0 mm is measured with the developing sleeve removed and the internal magnet exposed.
従って実際の現像装置に於ける現像領域ａでは、像保
持体Ｂと現像剤保持体としての現像スリーブ２との距離
は約50μｍ〜約1mm程度であり、該測定条件によって測
定された磁気拘束力分布は、実際の現像時に現像剤たる
トナーが受ける相対的な力の分布を表わしていると考え
られる。即ち上記の実際の測定要領において磁性体球10
として直径約1mmのフェライト球を用い、該フェライト
球10と現像スリーブ２との距離間隔を0.5mmに設定して
磁気拘束力を測定してもトナーとして受ける力の絶対値
そのものではないにせよ、トナーが受ける力の相対的な
磁気拘束力の大きさ、相対的な周方向分布を表わしてい
ると考えて良い。Therefore, in the developing area a in the actual developing device, the distance between the image carrier B and the developing sleeve 2 as the developer carrier is about 50 μm to about 1 mm, and the magnetic binding force measured under the measurement conditions. The distribution is considered to represent the distribution of the relative force that the toner as the developer receives during the actual development. That is, in the above-mentioned actual measurement procedure, the magnetic sphere 10
As a result, a ferrite sphere with a diameter of about 1 mm is used, and even if the distance between the ferrite sphere 10 and the developing sleeve 2 is set to 0.5 mm and the magnetic binding force is measured, it is not the absolute value of the force received as toner itself. It can be considered that it represents the magnitude of the relative magnetic binding force of the force applied to the toner, and the relative circumferential distribution.
（発明の効果） 以上、本発明によれば、尾引き現象や飛び散り現象に
よる画質変化を防止する効果がある他に、像保持体移動
方向と直角方向の細線像の濃度が薄くかすれたようにな
る現象や、細線が細る現象、或はベタ画像部の後縁部の
濃度が高くなる現象等による画質劣化の防止にも効果を
奏する。(Effects of the Invention) As described above, according to the present invention, in addition to the effect of preventing a change in image quality due to the trailing phenomenon and the scattering phenomenon, the density of a thin line image in the direction perpendicular to the moving direction of the image carrier is thin and faint Also, it is effective in preventing the deterioration of image quality due to such a phenomenon, a phenomenon of thin lines, or a phenomenon in which the density of the trailing edge portion of a solid image portion becomes high.
第１図は本発明の一実施例装置の法線方向磁束密度分布
及び法線方向磁気拘束力分布の説明図。 第２図は他の実施例装置の同上説明図。 第３図は更に他の実施例装置の同上説明図。 第４図は法線方向磁束密度分布の説明図。 第５図は本発明の適用できる現像装置の説明図。 第６図は法線方向磁束密度分布の説明図。 第７図（Ａ）・（Ｂ）は法線方向磁気拘束力の測定法例
の説明図。 第８図（Ａ）は良質画像の説明図、同図（Ｂ）は不良画
像の説明図。 第９図は従来例装置の、法線方向磁束密度分布及び法線
方向磁気拘束力の説明図。 Ａは現像装置、Ｂは電子写真感光ドラム等の像保持体、
２は現像剤担持部材としての回転現像スリーブ、３は磁
界発生部材としての固定のマグネットローラ、3a・3b・
3c・3dは磁石（磁極）、9a・9b・9c・9dは法線方向磁束
密度分布、Ｆ・Ｆ′は法線方向磁気拘束力分布。FIG. 1 is an explanatory diagram of a magnetic flux density distribution in a normal direction and a magnetic binding force distribution in a normal direction of an apparatus according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the same as another embodiment. FIG. 3 is an explanatory view of the same as the apparatus of another embodiment. FIG. 4 is an explanatory diagram of the magnetic flux density distribution in the normal direction. FIG. 5 is an explanatory view of a developing device to which the present invention can be applied. FIG. 6 is an explanatory diagram of the magnetic flux density distribution in the normal direction. FIGS. 7 (A) and 7 (B) are explanatory views of an example of a method for measuring the magnetic restraining force in the normal direction. FIG. 8A is an explanatory diagram of a good quality image, and FIG. 8B is an explanatory diagram of a defective image. FIG. 9 is an explanatory view of the magnetic flux density distribution in the normal direction and the magnetic restraining force in the normal direction in the conventional device. A is a developing device, B is an image carrier such as an electrophotographic photosensitive drum,
2 is a rotary developing sleeve as a developer carrying member, 3 is a fixed magnet roller as a magnetic field generating member, 3a, 3b,
3c and 3d are magnets (magnetic poles), 9a, 9b, 9c and 9d are magnetic flux density distributions in the normal direction, and FF's are magnetic binding force distributions in the normal direction.
Claims (4)
現像領域を形成し、この現像領域に現像剤を搬送する現
像剤担持部材と、この現像剤担持部材内の現像領域と対
向する位置に設けられた現像磁極と、を有する現像装置
において、 現像剤担持部材表面の法線方向の磁束密度のピーク位置
が現像領域内に存在し、磁気拘束力のピーク位置は現像
領域の終端近傍に存在し、磁束密度のピーク位置から像
保持体の移動方向下流側にむかって磁気拘束力が大きく
なることを特徴とする現像装置。1. A developer carrying member which forms a developing area opposite to an image carrier on which an electrostatic latent image is formed, and which conveys a developer to the developing area, and a developing area in the developer carrying member. In a developing device having a developing magnetic pole provided at a position opposite to the developing magnetic pole, the peak position of the magnetic flux density in the normal direction of the surface of the developer carrying member exists in the developing region, and the peak position of the magnetic binding force is the developing region. Present in the vicinity of the end of the magnetic flux density, and the magnetic binding force increases from the peak position of the magnetic flux density toward the downstream side in the moving direction of the image carrier.
中央であることを特徴とする請求項１に記載の現像装
置。2. The developing device according to claim 1, wherein the peak position of the magnetic flux density is substantially in the center of the developing area.
ク位置が存在することを特徴とする請求項１もしくは請
求項２に記載の現像装置。3. The developing device according to claim 1, wherein a peak position of the magnetic restraining force is present near the start end of the developing area.
度とピークとピークの1/2の点間の角度の比は0.5以上で
あることを特徴とする請求項１乃至請求項３の何れか１
つに記載の現像装置。4. The ratio of the angle between the peak and zero of the magnetic flux density in the normal direction and the angle between the peak and the half point of the peak is 0.5 or more. One of
The developing device according to any one of the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1168750A JPH087503B2 (en) | 1988-07-01 | 1989-06-30 | Development device |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63-164141 | 1988-07-01 | ||
| JP16414088 | 1988-07-01 | ||
| JP63-164140 | 1988-07-01 | ||
| JP16414188 | 1988-07-01 | ||
| JP1168750A JPH087503B2 (en) | 1988-07-01 | 1989-06-30 | Development device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02176686A JPH02176686A (en) | 1990-07-09 |
| JPH087503B2 true JPH087503B2 (en) | 1996-01-29 |
Family
ID=27322277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1168750A Expired - Lifetime JPH087503B2 (en) | 1988-07-01 | 1989-06-30 | Development device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH087503B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4610861B2 (en) * | 2003-03-20 | 2011-01-12 | 株式会社リコー | Developing device, image forming apparatus, process cartridge |
| JP6019878B2 (en) * | 2012-07-24 | 2016-11-02 | 富士ゼロックス株式会社 | Developing device and image forming apparatus |
| JP6938167B2 (en) * | 2016-03-08 | 2021-09-22 | キヤノン株式会社 | Image forming device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54183Y2 (en) * | 1973-07-18 | 1979-01-08 | ||
| JPS5930917Y2 (en) * | 1980-01-10 | 1984-09-03 | 株式会社リコー | magnetic brush developing device |
| JPS5732463A (en) * | 1980-08-06 | 1982-02-22 | Fuji Xerox Co Ltd | Developing device |
| JPS589156A (en) * | 1981-07-09 | 1983-01-19 | Fuji Xerox Co Ltd | Developing method |
-
1989
- 1989-06-30 JP JP1168750A patent/JPH087503B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02176686A (en) | 1990-07-09 |
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