JPH0352059B2 - - Google Patents
Info
- Publication number
- JPH0352059B2 JPH0352059B2 JP55147122A JP14712280A JPH0352059B2 JP H0352059 B2 JPH0352059 B2 JP H0352059B2 JP 55147122 A JP55147122 A JP 55147122A JP 14712280 A JP14712280 A JP 14712280A JP H0352059 B2 JPH0352059 B2 JP H0352059B2
- Authority
- JP
- Japan
- Prior art keywords
- potential
- image density
- image
- photoreceptor
- 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
- 108091008695 photoreceptors Proteins 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 15
- 238000011161 development Methods 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- 238000007796 conventional method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
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)
- Developing For Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Description
【発明の詳細な説明】
技術分野
本発明は、帯電された感光体の表面に画像露光
を施して静電潜像を形成し、形成された静電潜像
を、現像電極に対して現像バイアス電圧が印加さ
れた状態で反転現像する電子写真法における画像
濃度制御方法に関するものである。Detailed Description of the Invention Technical Field The present invention applies imagewise exposure to the surface of a charged photoreceptor to form an electrostatic latent image, and transfers the formed electrostatic latent image to a developing electrode with a developing bias. The present invention relates to an image density control method in electrophotography in which reverse development is performed while a voltage is applied.
従来技術
前記電子写真法は、電子写真複写機、レーザビ
ームプリンタ等において実用化されており、現像
画像濃度を調整する方法として、現像電極に対し
て印加される現像バイアス電圧、即ち、現像電極
の電圧を変化させる方法が知られている。Prior Art The electrophotographic method has been put to practical use in electrophotographic copying machines, laser beam printers, etc., and as a method of adjusting the developed image density, the development bias voltage applied to the development electrode, that is, the development electrode Methods of varying the voltage are known.
ところで、この様な画像濃度制御方法に関して
は、第１図に示される実験データから明らかな様
に、下記の如く問題点がある。なお、ここで、第
１図は、450Vに帯電された感光体の表面に画像
露光を施して静電潜像を形成し、この形成された
静電潜像を、現像電極として機能する現像スリー
ブに対して現像バイアス電圧を印加し、現像スリ
ーブの電位０〜300Vの下で現像することにより
得られる現像画像濃度を示すグラフである。 However, as is clear from the experimental data shown in FIG. 1, such an image density control method has the following problems. Here, FIG. 1 shows that an electrostatic latent image is formed by performing image exposure on the surface of a photoreceptor charged to 450V, and this formed electrostatic latent image is transferred to a developing sleeve that functions as a developing electrode. 2 is a graph showing the density of a developed image obtained by applying a developing bias voltage to the developing sleeve and developing under a potential of 0 to 300 V.
即ち、第１図に示される実験データから明らか
な様に、前記画像濃度制御方法に関しては、ライ
ン画像の画像濃度変化幅が狭く、また、ライン画
像とソリツド画像とでは画像濃度変化特性が大き
く異なつており、例えば、レーザビームプリンタ
の様に、複写画像のほとんどがライン画像からな
る場合の画像濃度調整には余り有効ではない。加
えて、画像濃度調整に伴い、ライン画像とソリツ
ド画像の画像濃度バランスが崩れ、画質の安定し
た現像画像が得られない。 That is, as is clear from the experimental data shown in FIG. 1, with regard to the image density control method, the image density change range for line images is narrow, and the image density change characteristics are significantly different between line images and solid images. Therefore, it is not very effective in adjusting image density when most of the copied image consists of line images, such as in a laser beam printer, for example. In addition, as the image density is adjusted, the image density balance between the line image and the solid image is disrupted, making it impossible to obtain a developed image with stable image quality.
目 的
本発明は、ライン画像の画像濃度変化幅が広
く、しかも、ライン画像とソリツド画像との画像
濃度変化特性の略同一な画像濃度制御方法を提供
することを目的とするものである。OBJECTS The present invention aims to provide an image density control method in which a line image has a wide range of image density change, and the image density change characteristics of a line image and a solid image are substantially the same.
要 旨
本発明は、感光体の帯電電位と現像電極の電位
との電位差を略一定に保ちつつ、現像電極の電位
および感光体の帯電電位を変化させて現像画像濃
度を調整することを要旨とするものである。SUMMARY OF THE INVENTION The gist of the present invention is to adjust the developed image density by changing the potential of the developing electrode and the charged potential of the photoreceptor while keeping the potential difference between the charged potential of the photoreceptor and the potential of the developing electrode substantially constant. It is something to do.
実施例
第２図は、本発明に係る画像濃度制御方法を実
施するための電子写真複写機の一例の概略を示
す。Embodiment FIG. 2 schematically shows an example of an electrophotographic copying machine for implementing the image density control method according to the present invention.
１は感光体ドラムで、複写時において図中反時
計回り方向に回動駆動される。２は帯電チヤージ
ヤ、３は画像露光装置である。４はいわゆる磁気
ブラシ現像方式を採用した現像装置であり、固定
された磁気ロール６を内蔵した現像スリーブ５の
外周面上に形成された絶縁性のキヤリアを含む２
成分系磁性現像剤の磁気ブラシにて感光体１の表
面に形成された静電潜像を摺擦して反転現像す
る。現像スリーブ５は現像バイアス電圧の印加さ
れる現像電極として機能するものであつて、図中
時計回り方向に回転駆動され、現像剤は専ら現像
スリーブ５の回転に基づいて現像スリーブ５上を
時計回り方向に搬送される。 Reference numeral 1 denotes a photosensitive drum, which is rotated counterclockwise in the figure during copying. 2 is an electrostatic charger, and 3 is an image exposure device. Reference numeral 4 denotes a developing device that employs a so-called magnetic brush developing method, and includes an insulating carrier formed on the outer peripheral surface of a developing sleeve 5 containing a fixed magnetic roll 6.
The electrostatic latent image formed on the surface of the photoreceptor 1 is rubbed with a magnetic brush of a component-based magnetic developer to perform reversal development. The developing sleeve 5 functions as a developing electrode to which a developing bias voltage is applied, and is rotationally driven in the clockwise direction in the figure, and the developer is exclusively moved clockwise on the developing sleeve 5 based on the rotation of the developing sleeve 5. conveyed in the direction.
７は転写チヤージヤ、８は複写機の分離チヤー
ジヤ、９は残留トナーのクリーニングブレード、
１０は残留電荷のイレーサランプである。 7 is a transfer charger, 8 is a separation charger of a copying machine, 9 is a residual toner cleaning blade,
10 is a residual charge eraser lamp.
１１はコントロール回路、１２は現像バイアス
電力供給回路、１３は帯電電力供給回路、１４は
感光体帯電電位検出器である。コントロール回路
１１は現像スリーブ電位と感光体帯電電位を制御
するもので、該コントロール回路１１による制御
の下に適正な電力が供給回路１２，１３を介し現
像スリーブ５と帯電チヤージヤ２とにそれぞれ供
給される。検出器１４は帯電チヤージヤ２にて帯
電された感光体帯電電位を直接検出するもので、
検出値はコントロール回路１１にフイードバツク
され、現実の帯電電位がコントロール回路１１に
よつて制御されるべき電位と同じかどうかをチエ
ツクし、必要であれば帯電チヤージヤ２への供給
電力を補正する。 11 is a control circuit, 12 is a developing bias power supply circuit, 13 is a charging power supply circuit, and 14 is a photoreceptor charging potential detector. The control circuit 11 controls the developing sleeve potential and the photoreceptor charging potential, and under the control of the control circuit 11, appropriate power is supplied to the developing sleeve 5 and the charging charger 2 through the supply circuits 12 and 13, respectively. Ru. The detector 14 directly detects the charged potential of the photoreceptor charged by the charger 2.
The detected value is fed back to the control circuit 11, and it is checked whether the actual charging potential is the same as the potential to be controlled by the control circuit 11, and if necessary, the power supplied to the charging charger 2 is corrected.
具体的には、画像濃度調整に際し、コントロー
ル回路１１があらかじめ所定の現像スリーブ電位
を選定し、この選定電位に対応した供給電力を供
給回路１２により現像スリーブ５に供給する。同
時に、コントロール回路１１にて前記選定電位と
の電位差が略一定である感光体帯電電位を選定
し、感光体ドラム１の表面がこの選定電位にまで
帯電されるのに必要な供給電力を供給回路１３に
より帯電チヤージヤ２に供給して感光体帯電電位
を制御するのである。この場合、感光体帯電電位
が前記選定電位と異なつている際には、帯電チヤ
ージヤ２への供給電力が検出器１４からのフイー
ドバツクにて補正されることは勿論である。 Specifically, when adjusting the image density, the control circuit 11 selects a predetermined developing sleeve potential in advance, and the supply circuit 12 supplies the developing sleeve 5 with power corresponding to the selected potential. At the same time, the control circuit 11 selects a photoreceptor charging potential with a substantially constant potential difference from the selected potential, and supplies the power necessary to charge the surface of the photoreceptor drum 1 to this selected potential. 13 to the charging charger 2 to control the charging potential of the photoreceptor. In this case, when the photoreceptor charging potential is different from the selected potential, the power supplied to the charging charger 2 is of course corrected based on the feedback from the detector 14.
第３図は以上の装置及び方法を用いた実験にて
得られた現像画像濃度の変化を示すグラフで、横
軸にとつた現像スリーブ５の電位に対して電位差
（Ｖ）；
Ｖ＝VO−VB
但し、VO：感光体帯電電位
VB：現像スリーブ電位
が200Vとなるように、感光体帯電電位を制御し
たもので、現像スリーブ５を100rpmで回転させ
た場合の実験データである。 FIG. 3 is a graph showing changes in developed image density obtained in experiments using the above apparatus and method, where the horizontal axis is the potential difference (V) with respect to the potential of the developing sleeve 5; V=V O -V B However, V O : Photoconductor charging potential V B : The photoconductor charging potential is controlled so that the developing sleeve potential is 200V, and this is experimental data when the developing sleeve 5 is rotated at 100 rpm. .
第３図から明らかなように、本実施例によつて
現像画像濃度を調整する場合、ライン画像の画像
濃度可変幅は十分に大きい。しかも、その際の画
像濃度変化特性は、ライン画像、ソリツド画像共
に近似している。このため、第１図に示される場
合と異なり、現像スリーブの電位の変動によつて
もライン画像とソリツド画像の画像濃度バランス
が崩れることもない。ここで、ライン画像の画像
濃度可変幅が大きくなつているのは、感光体帯電
電位と現像スリーブ電位との電位差が略一定にな
る様に制御されていることにより、現像の際に生
じるエツジ効果の影響が減少しているためと考え
られる。 As is clear from FIG. 3, when adjusting the developed image density according to this embodiment, the image density variable width of the line image is sufficiently large. Moreover, the image density change characteristics at that time are similar for both the line image and the solid image. Therefore, unlike the case shown in FIG. 1, the image density balance between the line image and the solid image is not disrupted even by fluctuations in the potential of the developing sleeve. Here, the reason why the image density variable width of the line image is large is that the potential difference between the photoreceptor charging potential and the developing sleeve potential is controlled to be approximately constant, and this is due to the edge effect that occurs during development. This is thought to be because the influence of
ところで、画像濃度調整のための具体的な態様
としては、コントロール回路１１中に現像画像濃
度調整用として、現像スリーブ電位を連続的に可
変とする回路を設けるか、所定の画像濃度が得ら
れる感光体電電位と現像スリーブ電位とをあらか
じめ複数断選定し、コントロール回路１１中に各
選定段階への切換回路を設けること等が考えられ
る。 By the way, as a specific mode for adjusting the image density, a circuit for continuously varying the developing sleeve potential is provided in the control circuit 11 for adjusting the developed image density, or a photosensitive circuit that can obtain a predetermined image density is provided. It is conceivable to select a plurality of body potentials and developing sleeve potentials in advance and provide a switching circuit for each selection stage in the control circuit 11.
なお、上記実施例においては、現像電極の電位
を変化させて現像画像濃度を調整する際に、現像
電極電位を基準として略一定の電位差を保つ様に
感光体帯電電位を制御する方法を示したが、逆
に、感光体帯電電位を変化させて現像画像濃度を
調整する様にしても良い。この場合、現像電極電
位は、感光体帯電電位を基準として制御されるこ
ととなる。 In addition, in the above example, when adjusting the developed image density by changing the potential of the developing electrode, a method was shown in which the photoreceptor charging potential is controlled so as to maintain a substantially constant potential difference based on the developing electrode potential. However, conversely, the density of the developed image may be adjusted by changing the charging potential of the photoreceptor. In this case, the developing electrode potential is controlled based on the photoreceptor charging potential.
効 果
本発明においては、感光体の帯電電位と現像電
極の電位との電位差が略一定に保たれつつ、現像
電極の電位および感光体の帯電電位が変化され、
その結果として現像画像濃度の調整が行なわれる
ので、ライン画像の画像濃度変化幅も広く、この
ため、本発明は、例えば、レーザビームプリンタ
の様に、複写画像のほとんどがライン画像からな
る場合の画像濃度調整にも有効である。加えて、
ライン画像とソリツド画像との画像濃度変化特性
も略同一であり、ライン画像とソリツド画像の画
像濃度バランスを実質的に崩すことなく、本発明
によれば、画質が安定した状態で現像画像の画像
濃度調整を行なうことができる。Effects In the present invention, the potential difference between the charging potential of the photoreceptor and the developing electrode is kept substantially constant, while the potential of the developing electrode and the charging potential of the photoreceptor are changed,
As a result, the developed image density is adjusted, and the range of image density change for line images is also wide. Therefore, the present invention is suitable for applications where most of the copied image consists of line images, as in the case of a laser beam printer, for example. It is also effective for adjusting image density. In addition,
The image density change characteristics of the line image and the solid image are also approximately the same, and according to the present invention, the image density balance between the line image and the solid image is not substantially disturbed. Concentration adjustment can be performed.
第１図は従来方法による現像画像濃度の変化を
示すグラフ、第２図は本発明に係る画像濃度制御
方法を実施するための電子写真複写機の一例概略
図、第３図は本発明の実施例における現像画像濃
度の変化を示すグラフである。
１……感光体ドラム、２……帯電チヤージヤ、
３……画像露光装置、４……現像装置、５……現
像スリーブ、１１……コントロール回路、１２…
…現像バイアス電力供給回路、１３……帯電電力
供給回路、１４……表面電位検出器。
FIG. 1 is a graph showing changes in developed image density according to the conventional method, FIG. 2 is a schematic diagram of an example of an electrophotographic copying machine for implementing the image density control method according to the present invention, and FIG. 3 is a graph showing changes in developed image density according to the conventional method. It is a graph showing a change in developed image density in an example. 1...Photosensitive drum, 2...Electrostatic charger,
3... Image exposure device, 4... Developing device, 5... Developing sleeve, 11... Control circuit, 12...
...Development bias power supply circuit, 13...Charging power supply circuit, 14...Surface potential detector.
Claims (1)
静電潜像を形成し、形成された静電潜像を、現像
電極に対して現像バイアス電圧が印加された状態
で反転現像する電子写真法における画像濃度制御
方法であつて、感光体の帯電電位と現像電極の電
位との電位差を略一定に保ちつつ、現像電極の電
位および感光体の帯電電位を変化させて現像画像
濃度を調整することを特徴とする画像濃度制御方
法。1 Electrophotography in which an electrostatic latent image is formed by imagewise exposure on the surface of a charged photoreceptor, and the formed electrostatic latent image is reversely developed with a developing bias voltage applied to a developing electrode. An image density control method in the method, in which the developed image density is adjusted by changing the potential of the developing electrode and the charged potential of the photoreceptor while keeping the potential difference between the charged potential of the photoreceptor and the potential of the developing electrode substantially constant. An image density control method characterized by:
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55147122A JPS5770570A (en) | 1980-10-20 | 1980-10-20 | Method for controlling image density |
| US06/308,173 US4432634A (en) | 1980-10-20 | 1981-10-02 | Electrophotographic copying apparatus |
| DE3140853A DE3140853C2 (en) | 1980-10-20 | 1981-10-14 | Electrographic copier with a device for controlling the image density of the copies |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55147122A JPS5770570A (en) | 1980-10-20 | 1980-10-20 | Method for controlling image density |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5770570A JPS5770570A (en) | 1982-05-01 |
| JPH0352059B2 true JPH0352059B2 (en) | 1991-08-08 |
Family
ID=15423030
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55147122A Granted JPS5770570A (en) | 1980-10-20 | 1980-10-20 | Method for controlling image density |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5770570A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2769574B2 (en) * | 1989-08-02 | 1998-06-25 | 石原産業株式会社 | Electrophotographic image forming method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5529859A (en) * | 1978-08-24 | 1980-03-03 | Canon Inc | Image former |
| JPS56158349A (en) * | 1980-05-12 | 1981-12-07 | Fuji Xerox Co Ltd | Reverse copying method |
-
1980
- 1980-10-20 JP JP55147122A patent/JPS5770570A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5529859A (en) * | 1978-08-24 | 1980-03-03 | Canon Inc | Image former |
| JPS56158349A (en) * | 1980-05-12 | 1981-12-07 | Fuji Xerox Co Ltd | Reverse copying method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5770570A (en) | 1982-05-01 |
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