JPH0731449B2 - Development method - Google Patents
Development methodInfo
- Publication number
- JPH0731449B2 JPH0731449B2 JP60097822A JP9782285A JPH0731449B2 JP H0731449 B2 JPH0731449 B2 JP H0731449B2 JP 60097822 A JP60097822 A JP 60097822A JP 9782285 A JP9782285 A JP 9782285A JP H0731449 B2 JPH0731449 B2 JP H0731449B2
- Authority
- JP
- Japan
- Prior art keywords
- developer
- voltage
- electrode
- bias
- 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.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/065—Arrangements for controlling the potential of the developing electrode
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Magnetic Brush Developing In Electrophotography (AREA)
- Developing For Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Description
【発明の詳細な説明】 〔発明の利用分野〕 本発明は電子写真や静電記録における現像装置に係り、
特に、磁性キャリアとトナーとから成る現像剤を用いる
場合に好適な現像方法に関する。Description: FIELD OF THE INVENTION The present invention relates to a developing device in electrophotography and electrostatic recording,
Particularly, the present invention relates to a developing method suitable when a developer including a magnetic carrier and a toner is used.
従来かかる現像装置には、現像特性を調整する目的で、
特開昭54-157628号に記載されているように、現像剤に
外部からバイアス電圧を印加する方法がとられている。
しかし、現像剤は使用期間につれて変わっていくにも拘
らず、常に、適正な値となるように配慮されていなかっ
た。画像を目視することにより、バイアス電圧を変える
方法も見受けられるが、この方法では果して適正なのか
どうかは何ら補償の限りではなく、経験や感に頼ること
になり、煩らわしかった。In the conventional developing device, in order to adjust the developing characteristics,
As described in JP-A-54-157628, a method of applying a bias voltage to the developer from the outside is adopted.
However, even though the developer changes with the period of use, it has not always been considered to have an appropriate value. There is also a method of changing the bias voltage by visually observing the image, but whether or not this method is proper is not limited to compensation but depends on experience and feeling, which is troublesome.
本発明の目的は、常に、適正なバイアス電圧を印加させ
るようになし、長期間にわたり安定な画像がだれにでも
得られるようにすることにある。An object of the present invention is to always apply an appropriate bias voltage so that a stable image can be obtained by anyone for a long period of time.
〔発明の概要〕 本発明の要点は、現像剤搬送ロール上に磁気的に吸着し
た現像剤の電気抵抗を現像剤搬送ロールに対置させた電
極により検知ないし監視し、その結果により、バイアス
電圧を調整し、現像剤の抵抗値変化にもとづく画像変化
を補償するようにしたことにある。[Summary of the Invention] The main point of the present invention is to detect or monitor the electric resistance of the developer magnetically adsorbed on the developer transport roll by means of an electrode opposed to the developer transport roll, and as a result, to detect the bias voltage. The adjustment is made to compensate for the image change due to the change in the resistance value of the developer.
第１図は本発明の実施例である。記録体１に形成した電
荷潜像を現像機２で現像し、現像剤３に含まれているト
ナーを記録体１上に付着させる。現像剤３は磁性キャリ
アとトナーとから成り、トナーは磁性キャリアに静電的
に吸着し、磁性キャリアはマグネットロール４の磁力に
よりスリーブ（現像ロール）５上に吸引させられる。マ
グネットロールを固定しておき、スリーブを矢印の方向
に回転すると、それにつれ現像剤２も回動搬送される。
このとき、規制板８で、一定量の現像剤が記録体の電荷
潜像の現像に寄与するように制限する。現像工程を経た
現像剤は一担スリーブ５からスクレーパ６で引きはが
し、再び使用する。このとき一部は検出コイル７内を通
過し、キャリアとトナーとの混合比を検出する。これ
は、現像につれて消費するトナーを補給する必要がある
ためである。トナーは補給装置（図示せず）から補充さ
れる。キャリアとトナーとの混合比を一定に保つことは
画濃度を一定に保持するためのみならず後述する現像剤
の抵抗を測定する際の精度保持にも必要である。FIG. 1 shows an embodiment of the present invention. The charge latent image formed on the recording body 1 is developed by the developing device 2, and the toner contained in the developer 3 is attached to the recording body 1. The developer 3 is composed of a magnetic carrier and toner. The toner is electrostatically adsorbed on the magnetic carrier, and the magnetic carrier is attracted onto the sleeve (developing roll) 5 by the magnetic force of the magnet roll 4. When the magnet roll is fixed and the sleeve is rotated in the direction of the arrow, the developer 2 is also rotated and conveyed.
At this time, the regulating plate 8 limits a certain amount of the developer so as to contribute to the development of the charge latent image on the recording medium. The developer that has undergone the developing process is peeled off from the supporting sleeve 5 by the scraper 6 and used again. At this time, a part passes through the detection coil 7 to detect the mixture ratio of the carrier and the toner. This is because it is necessary to replenish the toner consumed during development. Toner is replenished from a replenishing device (not shown). Keeping the mixing ratio of the carrier and the toner constant is necessary not only for keeping the image density constant, but also for keeping the accuracy when measuring the resistance of the developer described later.
スリーブ５にはバイアス電源13に接続されており直流電
圧ないしは直流電圧に交流電圧を重畳させた電圧を印加
する。このバイアス電圧は現像される画質を調整するも
ので、画像の印字濃度や背景濃度（カブリ）を改善す
る。例えば、記録体上の電荷のある所を現像する場合
（正規現像）にはトナーの帯電極性を潜像電荷に対し反
対極性とするが、このときはカブリが生じやすいため、
バイアス電圧の極性は記録体潜像電荷と同極性となし、
100〜200Vの電圧を印加する。一方、記録体上の電荷の
ない所を現像する場合（反転現像）には、トナーの帯電
極性を潜像電荷と同極性となし、バイアス電圧も同極性
とし現像に必要な電圧を外部から加える。この場合、印
加電圧は300〜800V程度と正規現像の場合に比しはるか
に大きな電圧を印加する。A bias power supply 13 is connected to the sleeve 5, and a DC voltage or a voltage in which an AC voltage is superimposed on a DC voltage is applied. This bias voltage adjusts the developed image quality and improves the print density and background density (fogging) of the image. For example, when developing a charged area on the recording medium (normal development), the charging polarity of the toner is set to the opposite polarity to the latent image charge, but at this time, fogging is likely to occur,
The polarity of the bias voltage is not the same as the latent image charge on the recording medium,
Apply a voltage of 100-200V. On the other hand, when developing an area on the recording medium where there is no electric charge (reverse development), the charging polarity of the toner is set to the same polarity as the latent image charge, the bias voltage is also set to the same polarity, and the voltage required for development is applied from the outside . In this case, the applied voltage is about 300 to 800 V, which is much higher than that in the case of regular development.
ところで現像剤はくり返し現像機内を回動するため、使
用につれてその特性が変化する。とくに、バイアス効果
が有効である現像剤抵抗が低い場合、その電気抵抗が大
きく変わる。これはキャリアの外側に絶縁体であるトナ
ー成分が付着するためと考えられている。電気抵抗の増
大はバイアス効果の低下につながる。そのため、現像剤
の使用程度に従い、バイアス電圧を調整し、良好な画
像、即ち、印字部の画濃度が高く、カブリの少ない状態
に保つことが必要である。By the way, since the developer repeatedly rotates in the developing machine, its characteristics change as it is used. In particular, when the developer resistance for which the bias effect is effective is low, the electric resistance changes greatly. It is considered that this is because the toner component, which is an insulator, adheres to the outside of the carrier. An increase in electric resistance leads to a decrease in bias effect. Therefore, it is necessary to adjust the bias voltage according to the degree of use of the developer so as to maintain a good image, that is, a state in which the image density of the printing portion is high and the fog is small.
本発明は、現像剤の電気抵抗を複雑な装置を用いること
なく測定或いは監視し、バイアス電圧を調整し良好な画
像をうるものである。電気抵抗測定のため本発明は測定
用電極を現像剤搬送ロール（第１図ではスリーブ５）に
対向して設け、その間を通過する現像剤の電気抵抗を測
定する。もちろん測定電極は必ずしも搬送ロールと対抗
する必要はないが安定測定のためには本法は好ましい。The present invention measures or monitors the electric resistance of the developer without using a complicated device and adjusts the bias voltage to obtain a good image. In order to measure the electric resistance, in the present invention, a measuring electrode is provided so as to face a developer carrying roll (sleeve 5 in FIG. 1), and the electric resistance of the developer passing between them is measured. Of course, the measuring electrode does not necessarily have to oppose the carrier roll, but this method is preferable for stable measurement.
第１図では現像剤の回動量を制限する規制板８を測定電
極としても使用している。この場合、規制板８の上手
（現像剤の流れに対向する側）には余分の現像剤が接す
るため、測定精度低下の原因となる。このような場合に
は、絶縁体９を取り付け、この面からの電流を阻止する
のが好ましい。In FIG. 1, the regulating plate 8 that limits the amount of rotation of the developer is also used as the measuring electrode. In this case, the excess developer comes into contact with the upper side of the regulation plate 8 (the side facing the flow of the developer), which causes a decrease in measurement accuracy. In such a case, it is preferable to attach the insulator 9 to block the current from this surface.
第１図において、規制板８は電流検出用抵抗10を通して
接地されているので、バイアス電源から現像剤を介して
規制板に流れ込む電流を検出することができる。抵抗10
に発生した電圧と基準電圧源12との差電圧をアンプ11を
通して増幅し、バイアス電源13の電圧をコントロールす
る。このようにしてバイアスの効果をほぼ一定に保持で
きる。例えば、使用始めでは300Vのバイアス電圧に対
し、500kp印刷使用後では600Vとすることができる。な
お、アンプ11の出力にモニタ14を接続し、その指示値に
従い、バイアス電源13を手動で切り変えて調整すること
も可能である。In FIG. 1, since the regulating plate 8 is grounded through the current detecting resistor 10, the current flowing from the bias power source to the regulating plate via the developer can be detected. Resistance 10
The difference voltage between the voltage generated at 1 and the reference voltage source 12 is amplified through the amplifier 11 to control the voltage of the bias power supply 13. In this way, the effect of bias can be maintained almost constant. For example, the bias voltage can be 300 V at the beginning of use and 600 V after the use of 500 kp printing. It is also possible to connect the monitor 14 to the output of the amplifier 11 and manually switch the bias power supply 13 for adjustment according to the indicated value.
このように本発明は現像ロールに対向して測定電極を設
けたものであるので、現像機の構造を大幅に変更するこ
となく、正確に現像剤の抵抗を測定できる長所がある。As described above, according to the present invention, since the measuring electrode is provided so as to face the developing roll, there is an advantage that the resistance of the developer can be accurately measured without significantly changing the structure of the developing machine.
この測定電極は、第２図に示すように測定の安定性、装
置間のバラツキを少くするために、搬送ロール17と測定
電極16のギャップは、現像剤の流れ方向に対し狭くして
おくのが良い。このようにすると、電極測定面に均一に
現像剤が接触し、測定値の変動が少ない。As shown in FIG. 2, in this measuring electrode, the gap between the transport roll 17 and the measuring electrode 16 is made narrower in the flow direction of the developer in order to reduce the measurement stability and the variation between the devices. Is good. By doing so, the developer uniformly contacts the electrode measurement surface, and the fluctuation of the measured value is small.
なお、第１図の説明では現像ロールと搬送ロールが同一
のものであるが、現像ロールと搬送ロールが別個のもの
では電極はどちらに対向させても良い。また、規制板と
測定電極を別々に設けても良い。In the description of FIG. 1, the developing roll and the transporting roll are the same, but if the developing roll and the transporting roll are separate, the electrodes may face each other. Further, the regulation plate and the measurement electrode may be separately provided.
第２図は、他の測定法及びバアス電圧コントロール法を
示すもので、この場合、抵抗測定用電源と、バイアス電
源とを別個に設けたものである。第１図のように両者兼
用とした場合、現像剤の種類や印加電圧により、検出電
流を一定としても同一のバイアス効果が得られないこと
がある。第２図では、このような弊害をさけ、制御効果
を大きくしたものである。FIG. 2 shows another measuring method and a bias voltage control method. In this case, a resistance measuring power source and a bias power source are separately provided. When both are used as shown in FIG. 1, the same bias effect may not be obtained depending on the type of the developer and the applied voltage even if the detection current is constant. In FIG. 2, such an adverse effect is avoided and the control effect is increased.
測定電極16には、測定電源15が接続され、電極から現像
剤に流れ込む電流を抵抗10に発生する電圧により検出す
る。印加電圧は通常100V程度である。抵抗10は測定電源
15と搬送ロール17とに接続されているのでバイアス電源
13とは独立に作動する。従って、電圧や電源の種類を最
適なものに選定できる。抵抗10に発生した電圧はアンプ
11で増幅し、バイアス電源13の電圧をコントロールす
る。また、モニタ14で監視することもできる。バイアス
電圧のコントロールは、例えば、電流10μＡのときバイ
アス600V、100μＡのとき400Vであるように設定する。
この値は予め、決められた現像剤の使用初期から末期ま
での検出電流値と適正なバイアス電圧を求めておきプロ
グラムしておけば良い。A measurement power supply 15 is connected to the measurement electrode 16, and the current flowing from the electrode into the developer is detected by the voltage generated in the resistor 10. The applied voltage is usually about 100V. Resistance 10 is the measurement power supply
Bias power supply because it is connected to 15 and transport roll 17.
It operates independently of 13. Therefore, the voltage and the type of power supply can be selected optimally. The voltage generated in resistor 10 is the amplifier
It is amplified by 11 and the voltage of the bias power supply 13 is controlled. It can also be monitored by the monitor 14. The control of the bias voltage is set so that the bias is 600 V when the current is 10 μA and 400 V when the current is 100 μA, for example.
This value can be programmed in advance by obtaining a predetermined detection current value and an appropriate bias voltage from the initial stage to the final stage of use of the developer.
ところで、測定用電源は、第１図では直流であるが、よ
り好ましい電源は低周波の交流である。By the way, the power source for measurement is direct current in FIG. 1, but a more preferable power source is low frequency alternating current.
直流で測定する場合の問題は、測定電極16と搬送ロール
17間には一定方向の電界が印加されるため電極やロール
にトナーが吸着、蓄積し、長期的な測定精度を低下させ
る。また、トナーが電荷量をもっているため電極へのト
ナーの吸脱着にともなう検出値変動が生じ、抵抗値の直
流電圧依存性が大きい。これらの弊害は測定に交流電圧
を使用することにより解決される。The problem when measuring with DC is the measurement electrode 16 and the carrier roll.
Since an electric field in a fixed direction is applied between 17, toner adheres to and accumulates on the electrodes and rolls, which lowers long-term measurement accuracy. Further, since the toner has a charge amount, the detection value fluctuates due to the adsorption and desorption of the toner on the electrode, and the resistance value has a large DC voltage dependency. These adverse effects are solved by using an alternating voltage for the measurement.
第３図は交流電圧で測定したときの現像剤抵抗値であ
る。使用した現像剤は平均粒形75μｍの球形に近い不定
形キャリアである。本発明に適した現像剤キャリアは、
この例のように、不定形で平均粒径25〜150μｍの鉄粉
キャリア、あるいは、フェライトキャリアで、現像剤と
したときバイアス印加効果が生じるに足る現像剤抵抗
（現像磁気ブラシを形成した状態で1011Ωcm、望ましく
は109Ωcm以下）であることが必要である。FIG. 3 shows the resistance value of the developer when measured with an AC voltage. The developer used is an irregular carrier having an average particle shape of 75 μm, which is close to a sphere. The developer carrier suitable for the present invention is
As shown in this example, an iron powder carrier having an irregular particle size and an average particle size of 25 to 150 μm or a ferrite carrier is used as a developer, and a developer resistance sufficient to produce a bias application effect (in a state where a developing magnetic brush is formed) 10 11 Ωcm, preferably 10 9 Ωcm or less).
この現像剤の抵抗値は第３図のように、測定周波数によ
り変り、使用前後の抵抗値差は低周波の方が大きくな
る。この結果から測定周波数は103Hz以下望ましくは、1
02Hz以下が好ましい。As shown in FIG. 3, the resistance value of this developer changes depending on the measurement frequency, and the difference in resistance value before and after use becomes larger at low frequencies. From this result, the measurement frequency is 10 3 Hz or less, preferably 1
0 2 Hz or less is preferable.
第４図は、第３図の現像剤を用い、印刷速度90cm/sで反
転現像した結果を示す。使用前、つまり、現像剤が新し
い場合は、抵抗値が低いのでバイアス効果が顕著で、30
0〜400Vで、カブリが生じることなく高濃度の画像が得
られる。しかし、更にバイアス電圧を上げていくと、現
像剤の耐圧電圧に達して短絡する。この現像剤を用いて
500kp印刷に供した後のバイアス効果は点線で示すよう
に、使用前に比し低下している。バイアス電圧500〜600
Vでほぼ使用前に近い画像濃度が得られる。しかし、600
V以上になるとカブリ濃度が増加し、実用に耐えない。FIG. 4 shows the result of reversal development using the developer of FIG. 3 at a printing speed of 90 cm / s. Before use, that is, when the developer is new, the bias effect is remarkable because the resistance value is low.
At 0 to 400V, high density images can be obtained without fogging. However, when the bias voltage is further increased, the withstand voltage of the developer is reached and a short circuit occurs. With this developer
The bias effect after being subjected to 500 kp printing is lower than that before use as shown by the dotted line. Bias voltage 500 to 600
With V, an image density close to that before use can be obtained. But 600
If it exceeds V, the fog density will increase and it will not be practical.
第３図、第４図の結果から、50Hzで抵抗値を測定した場
合、108Ωcmから５×108Ωcmへと抵抗が変わるのに対
し、バイアス電圧を350Vから550Vへと変えることによ
り、ほぼ、一定の画像濃度のプリントが得られる。そこ
で、第２図において測定電源を50Hz100Vとし、これを測
定電極に印加し、抵抗10に発生する電圧を検出し、この
検出電圧に対応して、バイアス電圧源VBの電圧を、使用
前350V,500kp印刷時550VとなるようにVBの制御係数を設
定する。このようにすることで、長期間にわたり、画像
濃度の安定した印刷が得られる。From the results of Fig. 3 and Fig. 4, when the resistance value is measured at 50Hz, the resistance changes from 10 8 Ωcm to 5 × 10 8 Ωcm, but by changing the bias voltage from 350V to 550V, A print with almost constant image density is obtained. Therefore, in FIG. 2, the measurement power source is set to 50 Hz 100 V, this is applied to the measurement electrode, the voltage generated in the resistor 10 is detected, and the voltage of the bias voltage source V B is set to 350 V before use in accordance with the detected voltage. Set the V B control coefficient so that it will be 550 V when printing 500 kp. By doing so, printing with stable image density can be obtained for a long period of time.
本発明によれば、搬送ロールに対置した電極により現像
剤の抵抗を使用状況に応じ検出し、それに対応した最適
バイアス電圧を印加するため、検出装置を複雑化するこ
となく精度良く検出でき、長期間にわたり、ほぼ一定の
画像が得られる。According to the present invention, the resistance of the developer is detected according to the usage condition by the electrode opposite to the transport roll, and the optimum bias voltage corresponding thereto is applied, so that the detection device can be accurately detected without complicating, and An almost constant image is obtained over a period of time.
第１図は本発明による現像装置の一実施例の系統図、第
２図は、現像剤抵抗の検出およびバイアス印加法の他の
実施例の系統図、第３図は本発明現像装置に適した現像
剤の抵抗の周波数特性図、第４図はバイアス電圧と画像
特性の関係を示す図である。 １……記録体、３……現像剤、５……スリーブ、８……
規制板、10……抵抗、13……バイアス電源。FIG. 1 is a system diagram of an embodiment of the developing device according to the present invention, FIG. 2 is a system diagram of another embodiment of the method for detecting developer resistance and bias applying method, and FIG. 3 is suitable for the developing device of the present invention. FIG. 4 is a diagram showing the frequency characteristic of the resistance of the developer, and FIG. 4 is a diagram showing the relationship between the bias voltage and the image characteristic. 1 ... Recording material, 3 ... Developer, 5 ... Sleeve, 8 ...
Regulation plate, 10 ... Resistance, 13 ... Bias power supply.
Claims (1)
アとトナーから成る現像剤を磁気的に現像剤搬送ロール
に吸着させ搬送しながら現像するものにおいて、トナー
濃度制御下にあって、前記現像剤搬送ロールに対向させ
て前記現像剤の電気抵抗を測定する電極を設け、前記電
極に略103Hz以下の低周波の交流電源を接続し、前記電
極に流れる交流成分に基づく電気抵抗を検知ないしは監
視し、これに基づき現像バイアス電圧を制御することを
特徴とする現像方法。1. A developing device for developing a charge latent image formed on a recording medium while magnetically adsorbing a developer consisting of a magnetic carrier and a toner onto a developer carrying roll, which is under toner concentration control, An electrode for measuring the electric resistance of the developer is provided in opposition to the developer transport roll, and a low-frequency AC power supply of approximately 10 3 Hz or less is connected to the electrode, and an electric resistance based on an AC component flowing in the electrode. Is detected or monitored, and the developing bias voltage is controlled based on this.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60097822A JPH0731449B2 (en) | 1985-05-10 | 1985-05-10 | Development method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60097822A JPH0731449B2 (en) | 1985-05-10 | 1985-05-10 | Development method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61256356A JPS61256356A (en) | 1986-11-13 |
| JPH0731449B2 true JPH0731449B2 (en) | 1995-04-10 |
Family
ID=14202425
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60097822A Expired - Lifetime JPH0731449B2 (en) | 1985-05-10 | 1985-05-10 | Development method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0731449B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3877244B2 (en) * | 1997-02-20 | 2007-02-07 | 株式会社リコー | Image forming apparatus |
| JP4826172B2 (en) * | 2005-08-22 | 2011-11-30 | 富士ゼロックス株式会社 | Developing device and image forming apparatus using the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5662275A (en) * | 1979-10-25 | 1981-05-28 | Canon Inc | Developing method |
| JPS5960452A (en) * | 1982-09-30 | 1984-04-06 | Fuji Xerox Co Ltd | Developing device of electrophotographic copying machine |
-
1985
- 1985-05-10 JP JP60097822A patent/JPH0731449B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61256356A (en) | 1986-11-13 |
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