JPS6187172A - Forming method of picture - Google Patents

Forming method of picture

Info

Publication number
JPS6187172A
JPS6187172A JP59209065A JP20906584A JPS6187172A JP S6187172 A JPS6187172 A JP S6187172A JP 59209065 A JP59209065 A JP 59209065A JP 20906584 A JP20906584 A JP 20906584A JP S6187172 A JPS6187172 A JP S6187172A
Authority
JP
Japan
Prior art keywords
density
image
exposure
voltage
developing bias
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP59209065A
Other languages
Japanese (ja)
Inventor
Yasushi Takagi
高木　保至
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP59209065A priority Critical patent/JPS6187172A/en
Publication of JPS6187172A publication Critical patent/JPS6187172A/en
Pending legal-status Critical Current

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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
    • G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
    • G03G15/5025—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control by measuring the original characteristics, e.g. contrast, density
    • 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

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Control Or Security For Electrophotography (AREA)

Abstract

PURPOSE:To obtain a recorded picture prevented from dirt on its ground and having sufficient contrast against a black part by setting up the quantity of exposure so as not to lose the contrast of a copied picture even if a developing bias is increased so that the density of the ground becomes required density in case of high ground density. CONSTITUTION:In case of an automatic mode, operation moves to a process P6 through a process P2, an exposing voltage which is a fixed value is set up in the process P6 and then a process P7 related to the measurement of original density is executed. A fiber cable 23 for measuring the density of an original is arranged on the moving direction side of an optical scanner unit 21. The surface of the original is successively irradiated by light guided through a hole 5a formed on a reflecting plate 5 and the reflected light is detected by a detector through a fiber cable 23 to measure the ground density of the original. The detected output from the detector is inputted to a microcomputer through an A/D converter, a process P8 related to operation is executed. Consequently, a developing bias voltage is set up to the calculated value, and under the condition, a developing process is executed.

Description

【発明の詳細な説明】 （技術分野） 本発明は画像形成方法に関し、よシ詳細には、原稿の地
肌濃度を検出して複写画像濃度を自動的に調整する画像
形成装置に適用し得る画像形成装置に関するものである
。[Detailed Description of the Invention] (Technical Field) The present invention relates to an image forming method, and more particularly, to an image forming method that can be applied to an image forming apparatus that detects the background density of a document and automatically adjusts the density of a copied image. The present invention relates to a forming device.

（従来技術） 従来、例えば次の画像形成方式が知られている。(Conventional technology) Conventionally, for example, the following image forming method is known.

それは、所謂、電子写真方式と称されるもので、光導電
性の感光体を原稿からの光像で露光することによシ静電
潜像を得、然る後、この静電潜像に静電現像方式によシ
トナーを付着させてトナー像を得、このトナー像を記録
紙上に転写し、定着工程を経て複写画像を得るのである
。This is the so-called electrophotographic method, in which an electrostatic latent image is obtained by exposing a photoconductive photoreceptor to a light image from an original, and then an electrostatic latent image is formed on this electrostatic latent image. Toner is deposited using an electrostatic development method to obtain a toner image, this toner image is transferred onto recording paper, and a copy image is obtained through a fixing process.

上記において、静電潜像上であって、原稿の地肌部に相
当する部分にトナーが付着すると地肌が汚れた記録画像
となり好ましくない。In the above, if toner adheres to a portion of the electrostatic latent image that corresponds to the background portion of the document, the recorded image will have a dirty background, which is undesirable.

そこで、静電潜像の地肌部にトナーを付着させない、所
謂、地肌を抜くために、感光体に現像バイアス電圧を与
え、トナーに電気的な力を作用させて上記地肌部に対す
るトナーの付着を妨げる方策が採られている。Therefore, in order to prevent the toner from adhering to the background part of the electrostatic latent image, or to remove the so-called background part, a developing bias voltage is applied to the photoreceptor, and an electric force is applied to the toner to prevent the toner from adhering to the background part. Measures are being taken to prevent this.

しかし、その際、感光体上に結像される原稿からの光像
の光強度、即ち、露光光量は地肌部と黒部とのコントラ
ストを出すという観点からは配慮されていない。このた
め、地肌が白くない場合、つまシ濃い地肌を有する原稿
について、きれいな地肌の記録像を得るべく、原稿地肌
に対応する静電潜像上での地肌部分の現像バイアスを高
く制御すると、原稿黒部に対応する静電潜像部との間に
。However, in this case, no consideration is given to the light intensity of the light image from the document formed on the photoreceptor, that is, the amount of exposure light from the viewpoint of creating a contrast between the background portion and the black portion. For this reason, when the background is not white, in order to obtain a recorded image with a clear background for a document with a dark background, if the development bias of the background part on the electrostatic latent image corresponding to the document background is controlled to be high, between the electrostatic latent image area corresponding to the black area.

画像として必要なコントラストを得るために必要とされ
る電位差がとれなくなり、コントラストが出なくなると
いう問題を生ずる。A problem arises in that the potential difference necessary to obtain the contrast necessary for the image cannot be maintained, and the contrast is no longer produced.

（目　　的） 従って、この発明の目的は、地肌の濃い原稿についても
コントラストを出すことのできる画像形成方法を提供す
ることにある。(Objective) Therefore, an object of the present invention is to provide an image forming method that can produce contrast even on a document with a dark background.

（構　成） 本発明は上記の目的を達成させるため、通常画調の原稿
の中、地肌濃度が高いものに対し、該地肌部が所望の複
写濃度になる様に現像バイアスを高めた場合にも複写画
像のコントラストが損なわれない様に露光光量を設定す
ることを特徴とする。(Structure) In order to achieve the above-mentioned object, the present invention provides a method for increasing the development bias so that the background part has a desired copy density for a document with a high background density among originals with a normal image tone. Also, the exposure light amount is set so that the contrast of the copied image is not impaired.

以下１本発明の一実施例に基づいて具体的に説明する。A detailed description will be given below based on one embodiment of the present invention.

第１図は、画像形成装置の露光ランプに、一定の露光電
圧をかけて露光した際の原稿濃度と、感光体上この原稿
像に対応する静電潜像電位との関係を示したものである
。この図は任意に設定された露光電圧の下で各種の濃度
の原稿を露光し、感光体上に担持された静電潜像電位を
計測したデータに基づいて作成したものである。Figure 1 shows the relationship between the original density and the electrostatic latent image potential corresponding to this original image on the photoreceptor when a constant exposure voltage is applied to the exposure lamp of the image forming apparatus. be. This figure was created based on data obtained by exposing originals of various densities under arbitrarily set exposure voltages and measuring the potential of the electrostatic latent image carried on the photoreceptor.

図示の各露光電圧ＥＯ＋　ＥＯＩ　ｍ　Ｅｌ　ｅ　ＥＯ
３＋　Ｅ３はＥ。Each exposure voltage EO+ EOI m El e EO shown in the figure
3+ E3 is E.

＜　ＥＯＩ　＜　Ｅｓ　＜　Ｅ６３　＜　Ｅ３なる関係
を有し、静電潜像電位（原稿画像濃度）が低い時程、変
化率が大きく、高くなる程、変化率が小さくなるという
傾向を示す。<EOI<Es<E63<E3, which shows a tendency that the lower the electrostatic latent image potential (original image density), the larger the rate of change, and the lower the electrostatic latent image potential (original image density), the smaller the rate of change.

従って、原稿濃度が低い原稿地肌の範囲、例えば、任意
の原稿画像濃度（Ｉ　−Ｄ＝　０．３５　）に着目した
とき、Ｅ、　）　Ｅ、なる関係にある各露光光量につい
ての潜像電位を地肌部と黒部との差について調べると、
露光電圧Ｅ１についての地肌部（ＩＤ＝０．３５）と黒
部（ＩＤ＝１．２）との潜像電位差Ｖ５−■３−△Ｖ及
び露光電圧Ｅ、についての地肌部（ＩＤ−０，３５）と
黒部（ＩＤ＝１．２＞との潜像電位差ｖ７−ｖ４−△Ｖ
ｏに違いがあられれることになる。Therefore, when focusing on the range of the original background where the original density is low, for example, an arbitrary original image density (I - D = 0.35), the latent image potential for each exposure light amount with the relationship E, ) E, When examining the difference between the background and black areas,
The latent image potential difference V5-■3-ΔV between the background area (ID=0.35) and the black area (ID=1.2) for the exposure voltage E1 and the background area (ID-0,35 for the exposure voltage E) ) and the black part (ID=1.2>) latent image potential difference v7-v4-△V
There will be a difference in o.

即ち、露光光量を一定の値に固定し、原稿画像濃度に応
じて現像バイアスを変化させて自動的に濃度調整する場
合、露光電圧Ｅ１に関しては、　通常の原稿の中、比較
的濃度が高い、原稿画像濃度（Ｉ　Ｄ　＝　０．３５　
）の地肌にトナーを付着させない様にするのに要するバ
イアス電圧は潜像電位ｖ３と同じ値かそれ以上となる。That is, when fixing the exposure light amount to a constant value and automatically adjusting the density by changing the developing bias according to the original image density, the exposure voltage E1 is set when the density is relatively high among normal originals. Original image density (I D = 0.35
) The bias voltage required to prevent toner from adhering to the background of the image is equal to or higher than the latent image potential v3.

又、同原稿黒部（ＩＤ＝１．２）での潜像電位はｖ６で
あるので、コントラストに寄与する電位差は最大△Ｖで
ある。Furthermore, since the latent image potential in the black portion of the original (ID=1.2) is v6, the potential difference contributing to the contrast is at most ΔV.

一方、もし、露光電圧をＥｌよシ低い露光電圧Ｅ。On the other hand, if the exposure voltage is lower than El, the exposure voltage E is lower than El.

に設定したとすると、上記と同じ原稿を用いた場合、コ
ントラストに寄与する電位差は△ｖ０であシ、上記露光
電圧曲線の性質によシ△ｖｏ＜ΔＶとなるから、コント
ラストを大きくするには露光電圧は高い方が有利といえ
る。If the same original as above is used, the potential difference contributing to the contrast is △v0, and depending on the nature of the exposure voltage curve, △vo<ΔV. Therefore, in order to increase the contrast, It can be said that a higher exposure voltage is advantageous.

こうして露光電圧が定まったならば、これを固定して原
稿画像濃度を測定し、その原稿画像濃度情報に基づいて
現像バイアスを変化させて現像すれば、適正コントラス
トの記録画像を得ることができる。Once the exposure voltage is determined in this way, a recorded image with appropriate contrast can be obtained by fixing the exposure voltage, measuring the original image density, and performing development by changing the developing bias based on the original image density information.

ところで、上記の如く、原稿画像濃度情報に基づき現像
バイアス電圧を自動的に変化させて（露光光量は一定値
に固定）画像調整を行なう自動調整モードの他に、手動
により露光光量を変化させて（現像バイアス電圧は一定
値に固定）画像調整を行なう手動調整モードを有し、こ
れらの各モードを選択的に切換え自在の画像形成装置に
おいては、オペレータが自動調整モードから手動調整モ
ードに選択した場合、雑光光量を何らかの値に設定しな
ければならない。この設定されるべき露光光量は、操作
の簡便さからすれば、一般に多く用いられる通常の画像
濃度の原稿（以下、標準原稿という）についての地肌（
例えばＩＤ＝０．１程度）を抜く、即ちトナーの付着を
避けることができる値とするのが好ましい。そこで、こ
の様な標準原稿についての地肌を抜き得る手動モードに
おける露光光量を標準露光光量、これに対応する露光電
圧を標準露光電圧と称すれば、標準露光電圧を決定する
ことによシ、これに応じて固定値たる現像バイアス電圧
の値を決定することができる。By the way, as mentioned above, in addition to the automatic adjustment mode in which image adjustment is performed by automatically changing the developing bias voltage based on the document image density information (the exposure light amount is fixed at a constant value), there is also a mode in which the exposure light amount is manually changed. (Development bias voltage is fixed at a constant value) Image forming apparatuses that have a manual adjustment mode for image adjustment and can selectively switch between these modes have the ability to switch from automatic adjustment mode to manual adjustment mode when the operator selects manual adjustment mode. In this case, the amount of miscellaneous light must be set to some value. From the viewpoint of ease of operation, the exposure light amount to be set should be determined based on the background (hereinafter referred to as standard document) of a commonly used document with a normal image density (hereinafter referred to as a standard document).
For example, it is preferable to set the value to ID=0.1), that is, to a value that can avoid toner adhesion. Therefore, if we call the exposure light amount in manual mode that can extract the background for such standard originals the standard exposure light amount, and the corresponding exposure voltage the standard exposure voltage, then by determining the standard exposure voltage, The value of the developing bias voltage, which is a fixed value, can be determined according to.

その場合、自動調整モード時において固定値として設定
されていた露光電圧例えば、上記例にて説明した露光電
圧Ｅ１例えば７０Ｖをそのまま当該手動モード時におけ
る標準露光電圧として採用することができれば、標準原
稿を用いる限シにおいて、自動モード、手動モード相互
の切換え時に露光電圧に変化を生じないので操作が容易
であると同時にプログラム制御上においても簡単である
といえる。In that case, if the exposure voltage that was set as a fixed value in the automatic adjustment mode, for example, the exposure voltage E1, for example 70V, explained in the above example, could be adopted as the standard exposure voltage in the manual mode, it would be possible to convert the standard document into In use, there is no change in exposure voltage when switching between automatic mode and manual mode, so it can be said that it is easy to operate and also easy to program control.

しかし、手動モードにおいて標準原稿用として自動的に
設定される標準露光電圧と、自動モードにおいて固定さ
れた値として設定される固定露光電圧とを同じ値にする
ことは、次の理由によシ、できない。However, setting the standard exposure voltage that is automatically set for standard documents in manual mode and the fixed exposure voltage that is set as a fixed value in automatic mode to the same value is not recommended for the following reasons. Can not.

その理由というのは、例えば、自動モードでの固定露光
電圧をＥ、とすると、この露光電圧でようやく標準原稿
の地肌（ＩＤ＝０．１）を現像バイアス（””Ｖ２）で
抜（ことができたのであるから、仮にこの露光電圧Ｅ１
を適用したままで手動モードに切換えた場合には、上記
現像バイアス電圧（−”Ｖｚ）も固定されるので、仮に
標準原稿よシも地肌濃度が濃い原稿（ＩＤ＝０．３５）
についての地肌を抜くには、露光電圧を変化させてＥｌ
よりもかなり大きい露光電圧Ｅ３に設定しなければなら
ない。The reason for this is, for example, if the fixed exposure voltage in automatic mode is E, then at this exposure voltage it is possible to finally remove the background (ID=0.1) of a standard document using the developing bias (""V2). Therefore, if this exposure voltage E1
If you switch to manual mode with the above applied, the developing bias voltage (-”Vz) will also be fixed, so even if the original is a standard original or an original with a high background density (ID=0.35)
To remove the background, change the exposure voltage and increase El.
It is necessary to set the exposure voltage E3 to be considerably larger than that.

しかし、露光電圧をそのように高めることは、露光光源
部の発熱を増すことから種々の制約を受け、事実上不可
能である。However, increasing the exposure voltage to such a degree is subject to various restrictions due to increased heat generation in the exposure light source, and is virtually impossible.

そこで、自動モードから手動モードへ切換えた時に、ｎ
光電圧を標準露光電圧Ｅ１よシも低いところの露光電圧
Ｅｅｌに切換えたとすれば、標準原稿の地肌（ＩＤ＝０
．１）を抜くのに必要な現像バイアス電圧はＶＯ２とな
るから、この現像バイアス電圧ＶＯ２を手動モード時に
おける固定現像バイアス電圧に設定したとすれば、標準
原稿よシも地肌濃度が濃い原稿（ＩＤ＝０．３５）につ
いての地肌を抜（には、露光電圧Ｅ３よシも低い露光電
圧ＥＯ３で十分となり、上記発熱に伴なう制約から解放
される訳である。Therefore, when switching from automatic mode to manual mode, n
If the photovoltage is switched to the exposure voltage Eel, which is lower than the standard exposure voltage E1, the background of the standard original (ID=0
．． The development bias voltage required to remove 1) is VO2, so if this development bias voltage VO2 is set as the fixed development bias voltage in manual mode, it will be possible to handle originals with a high background density (ID) as well as standard originals. =0.35), the exposure voltage EO3, which is lower than the exposure voltage E3, is sufficient, and the above-mentioned restrictions associated with heat generation are released.

従って１例えば自動モードにおいて固定露光電圧が露光
電圧Ｅｌで設定されたとすると、手動モードでは標準露
光電圧として上記露光電圧Ｅ１よシも低い露光電圧ＥＯ
Ｉに設定すればよい。Therefore, 1. For example, if the fixed exposure voltage is set at exposure voltage El in automatic mode, then in manual mode, the standard exposure voltage is set to exposure voltage EO, which is lower than the above exposure voltage E1.
Just set it to I.

このように、自動モードから手動モードに切換える場合
は、光源の発熱を低くする観点から、手動モードにおけ
る固定露光電圧は自動モードにおける標準露光電圧よシ
も小さく設定されるべきこととなる。In this way, when switching from automatic mode to manual mode, the fixed exposure voltage in manual mode should be set lower than the standard exposure voltage in automatic mode, from the viewpoint of reducing heat generation of the light source.

上記と逆に、手動モードから自動モードに切換える場合
を考えると、自動モードでは現像バイアスが可変とされ
、露光電圧が固定される。従って。Contrary to the above, if we consider the case of switching from manual mode to automatic mode, in automatic mode the developing bias is variable and the exposure voltage is fixed. Therefore.

地肌の濃い原稿から地肌汚れのない接写画像を得るだめ
の現像バイアス電圧は、黒部とのコントラストを出すと
の観点からすると、その可変域の上限を一定値以下に抑
えて地肌部と黒部との潜像電位差に巾をもたせることが
必要となる。The developing bias voltage required to obtain a close-up image without background stains from an original with a dark background is, from the perspective of creating contrast with the black area, the upper limit of its variable range is kept below a certain value and the difference between the background area and the black area is It is necessary to give a range to the latent image potential difference.

ここで、現像バイアス電圧の可変域の上限を所定の一定
値以下に抑えることとしたのは、原稿黒部の濃度を一定
（ＩＤ＝１．０）以上に維持しつつ、そのような黒部に
対して所要のコントラストを維持するには黒部の潜像電
位よシ低い一定の電位中以上を確保した地肌部の潜像電
位となす必要があり、結局、そのような地肌部の潜像電
位から定まる現像バイアス電圧も所定の一定値よシ低く
設定しなければコントラストを出せないからである。Here, the reason why we decided to suppress the upper limit of the variable range of the developing bias voltage to below a predetermined constant value is to maintain the density of the black part of the document above a certain level (ID = 1.0) and to In order to maintain the required contrast, it is necessary to ensure that the latent image potential of the background area is a certain level lower than the latent image potential of the black area.In the end, it is determined from the latent image potential of the background area. This is because contrast cannot be produced unless the developing bias voltage is also set lower than a predetermined constant value.

このように、コントラストに寄与する黒部と地肌部との
潜像電位差を大きくとるには、第１図に示す如く原稿画
像濃度ＩＤ＝１．０以上の黒部に対応する潜像電位が露
光光量の大小にさほど影響を受けないことから、はぼ一
定の黒部溜像電位に対し、地肌部潜像電位を低（する程
有効である。そのためには、又、第１図の各露光電圧曲
線の性質から、よシ大きな露光電圧を自動モードにおけ
る固定露光電圧に選定するのが望ましく、そのような固
定露光電圧から得られる固定露光光量は手動モードにお
ける標準露光光量と比べれば、それよシも大きくなるの
である。In this way, in order to increase the latent image potential difference between the black part and the background part, which contribute to the contrast, the latent image potential corresponding to the black part with the original image density ID = 1.0 or more is lower than the amount of exposure light, as shown in Fig. 1. Since it is not affected by the magnitude, it is more effective to lower the latent image potential of the background area compared to the almost constant black area image potential. Due to its nature, it is desirable to select a higher exposure voltage as the fixed exposure voltage in automatic mode, and the fixed exposure light amount obtained from such a fixed exposure voltage is much larger than the standard exposure light amount in manual mode. It will become.

従って、自動モード、手動モード相互の切換え時におい
ては、露光電圧の切換えが不可欠となる。Therefore, when switching between automatic mode and manual mode, it is essential to switch the exposure voltage.

次に、画像形成装置の一例として自動モード、手動モー
ド切換機能付の電子写真複写機について、実施例を説明
する。Next, an embodiment of an electrophotographic copying machine with an automatic mode/manual mode switching function will be described as an example of an image forming apparatus.

第２図におりて符号ｌは透明な原稿載置台を示し、この
上に原稿が載置された上、圧板２で抑えられて露光走査
が行なわれる。符号３は感光体ドラムを示し、上記露光
走査に際しては、光源４からの光が原稿に反射されて、
この反射光が、光源４と共に示矢２２方向に移動する反
射板５、第１ミラーＭｌ、第２ミラーＭ２、第３ミラー
Ｍ３を介し、さらに、結像レンズ６及び第４ミラーＭ４
を介して、回転している当該感光体ドラム３上に結像、
露光される。感光体ドラム３の周囲にはよく知られる様
だ、主帯電器７．現像ユニット８．ガイド板９、転写・
分離帯電器１０．ガイド板１１．クリーニングユニ、ト
１２、除電ランプ１３等が配設されている。なお、露光
光は主帯電器７と現像ユニット８との間の一様に帯電さ
れた感光体上に結像され静電潜像が担持される。この静
電潜像は現像ユニット８にてトナー現像によシ顕像化さ
れ、カセット１４からガイド板９を介して送給される記
録紙Ｓ上に転写・分離帯電器１０の働きで転写され１次
いで該記録紙Ｓはガイド板１１上に分離される。そして
該記録紙Ｓは定着ユニ、ト１５を経て定着操作が施され
、トレイ１６に排出される。In FIG. 2, reference numeral 1 denotes a transparent document mounting table, on which the document is placed and held down by a pressure plate 2 for exposure scanning. Reference numeral 3 indicates a photosensitive drum, and during the exposure scanning, light from a light source 4 is reflected by the original,
This reflected light passes through the reflecting plate 5, the first mirror Ml, the second mirror M2, and the third mirror M3, which move in the direction of the arrow 22 together with the light source 4, and further through the imaging lens 6 and the fourth mirror M4.
An image is formed on the rotating photoreceptor drum 3 via
exposed to light. Surrounding the photoreceptor drum 3 is a main charger 7, which seems to be well known. Developing unit 8. Guide plate 9, transfer/
Separation charger 10. Guide plate 11. A cleaning unit 12, a static elimination lamp 13, etc. are provided. Note that the exposure light forms an image on a uniformly charged photoreceptor between the main charger 7 and the developing unit 8, so that an electrostatic latent image is carried thereon. This electrostatic latent image is visualized by toner development in the developing unit 8, and transferred onto the recording paper S fed from the cassette 14 via the guide plate 9 by the function of the transfer/separation charger 10. First, the recording paper S is separated onto a guide plate 11. Then, the recording paper S is subjected to a fixing operation through a fixing unit, tray 15, and is discharged to a tray 16.

一方、転写後の感光体はクリーニングユニット１２で残
留トナーを除去されてから除電ランプ１３にて残留電荷
が除電されて、主帯電器７による次の帯電に備えられる
。On the other hand, residual toner is removed from the photoreceptor after the transfer by a cleaning unit 12, and residual charges are removed by a charge removal lamp 13, so that the photoreceptor is prepared for the next charge by the main charger 7.

この電子写真複写機の操作部は第３図に示す如きスイッ
チ配列になっている。図において、符号１７はモード選
択キーを示し、これを押す毎に自動モードと手動モード
とが順次交互に切換わる様になっている。このモード選
択キー１７の操作と連動して、自動モードが選択された
ときには「自動濃度調整」と表示されたランプ１８が点
灯し１手動モードが選択された場合には、消灯してオペ
レータにモードの選択状態を知らせる。符号１８．１９
は各々手動キーを示し、手動キー１８を押すと、押す毎
に濃い複写画像が得られる傾向に露光電圧のレベルが段
階的に移動し１手動キー１９を押すと、上記と逆の傾向
に移動する。符号２０は手動キー１８゜１９による操作
に際してのゲージ鉢な示し１手動キー１８又は１９を押
圧する毎に発光表示部りの点灯位置が移動する様になっ
てｂる。The operation section of this electrophotographic copying machine has a switch arrangement as shown in FIG. In the figure, reference numeral 17 indicates a mode selection key, and each time the key is pressed, automatic mode and manual mode are sequentially and alternately switched. In conjunction with the operation of this mode selection key 17, when the automatic mode is selected, the lamp 18 displaying "Auto Density Adjustment" lights up, and when the 1 manual mode is selected, the lamp 18 turns off and prompts the operator to select the mode. Indicates the selection status of. Code 18.19
each indicates a manual key, and each time the manual key 18 is pressed, the exposure voltage level moves step by step in a manner that tends to produce a darker copy image, and when the manual key 19 is pressed, the exposure voltage level moves in the opposite direction to the above. do. Reference numeral 20 indicates a gauge pot when operating the manual keys 18 and 19.1 The lighting position of the light emitting display portion moves every time the manual key 18 or 19 is pressed.

当該電子写真複写機のメインスイッチの投入がなされる
と、予めプログラムされた通シ、自動モード或いは手動
モードに設定される。この設定モードが、オペレータの
希望するモードと異なっていれば、オペレータによるモ
ード選択キー１７の指示操作によシモードが再設定され
る。When the main switch of the electrophotographic copying machine is turned on, it is set to a preprogrammed mode, automatic mode, or manual mode. If this setting mode is different from the mode desired by the operator, the mode is reset by the operator's instruction operation of the mode selection key 17.

手動モードで複写開始された場合には、第４図。FIG. 4 when copying is started in manual mode.

第５図に示す如く、複写開始に係るプロセスＰ１を経て
モード判定に係るプロセスＰ２でモードの設定状態が判
断され、現像バイアス電圧の設定に係るプロセスＰ３に
いく。そして、予め定められて−る固定値たる現像バイ
アス電圧がプロセスＰ３において設定され１次いで、オ
ペレータによシ予め指示された発光表示部りの指示発光
位置に対応した露光電圧設定用のノツチの位置がノツチ
判定に係るプロセスＰ４にて判定され、この判定結果に
基づいて露光電圧が露光光量制御に係るプロセスＰ５に
て設定される。As shown in FIG. 5, after a process P1 relating to the start of copying, a mode setting state is determined in a process P2 relating to mode determination, and the process proceeds to process P3 relating to setting the developing bias voltage. A developing bias voltage, which is a predetermined fixed value, is set in process P3. Next, the notch for setting the exposure voltage is positioned in accordance with the designated light emitting position of the light emitting display section, which has been previously designated by the operator. is determined in a process P4 related to notch determination, and based on this determination result, an exposure voltage is set in a process P5 related to exposure light amount control.

一方、自動モードが選択された場合には、第４図、第６
図に示す如くプロセスｈを経て露光光量制御に係るプロ
セスＰ６にいき、ここで固定値たる露光電圧が設定され
る。On the other hand, if the automatic mode is selected,
As shown in the figure, the process goes through process h to process P6 related to exposure light amount control, where an exposure voltage as a fixed value is set.

次に、原稿濃度（地肌）測定に係るプロセスＰ７が行な
われる。つまシ、第２図における第１ミラー　Ｍｌ、第
２ミラーＭ２　、第３ミラーＭ３、光源４゜反射板５等
からなる光学スキャナユニット２１が示矢２２方向に移
動して露光走査が行なわれるのであるが、当該光学スキ
ャナーユニット２１の移動方向側には原稿濃度測定用の
ファイバケーブル２３が設けてあり、第７図に示す如く
、反射板５に設けた光の通過穴５ａより導いた光によシ
原稿載置台１上の原稿面が順次照射され、その反射光が
該ファイバーケーブル２３を通して検知器で受光されて
原稿の地肌濃度が測定されるのである。Next, a process P7 related to document density (background) measurement is performed. The optical scanner unit 21 consisting of the first mirror Ml, the second mirror M2, the third mirror M3, the light source 4°, the reflector 5, etc. in FIG. 2 moves in the direction of the arrow 22 to perform exposure scanning. However, a fiber cable 23 for measuring the original density is provided on the moving direction side of the optical scanner unit 21, and as shown in FIG. The surface of the document on the document table 1 is sequentially irradiated, and the reflected light is received by a detector through the fiber cable 23 to measure the background density of the document.

この検知器の検出出力は、　Ａ／Ｄ変換回路を経てマイ
クロコンピュータ−に入力され、演算に係るプロセスＰ
８が実行される。このプロセスＰ８においては、予じめ
備えであるデータと上記検出出力が比較されて、原稿地
肌を最適条件で抜くことのできる現像バイアス電圧が算
出される。そして、現像バイアス制御係るプロセスＰ９
において、上記により算出された現像バイアス電圧に設
定され、この条件で現像プロセスが行なわれる訳である
。The detection output of this detector is input to the microcomputer via the A/D conversion circuit, and the process P related to calculation is performed.
8 is executed. In this process P8, the above-mentioned detection output is compared with data prepared in advance, and a developing bias voltage that can remove the background of the original under optimal conditions is calculated. And process P9 related to development bias control
In this case, the developing bias voltage calculated above is set, and the developing process is performed under these conditions.

ここで１手動モードから自動モードへ変換した際、現像
バイアス電圧の制御範囲及び設定されるべき固定露光光
量をどのようにすべきかについて具体的に説明する。Here, when converting from 1 manual mode to automatic mode, the control range of the developing bias voltage and the fixed exposure light amount to be set will be specifically explained.

先ず、現像バイアス電圧の制御範囲は第８図に示す如く
、複写像黒部の濃度が約１．０以下になると地肌部との
濃度差が少なくなり、見かけ上、非常にコントラストが
悪くなるため、現像バイアスの値の上限を４００ｖ以下
にする必要がある。First, as shown in FIG. 8, the control range of the developing bias voltage is as shown in FIG. It is necessary to set the upper limit of the developing bias value to 400 V or less.

一方、第９図（ａ）において、直線２４は手動モード時
における原稿地肌濃度に対応した露光電圧の変化特性を
示し、標準露光光量を得るための標準露光電圧は符号Ｅ
ｘで示されている。On the other hand, in FIG. 9(a), a straight line 24 indicates the change characteristic of the exposure voltage corresponding to the background density of the original in manual mode, and the standard exposure voltage for obtaining the standard exposure light amount is marked E.
Indicated by x.

そして、この標準露光電圧Ｅｘに対応する固定現像バイ
アス電圧は第９図（ｂ）に符号Ｖｘで示す値であるとす
る。It is assumed that the fixed developing bias voltage corresponding to this standard exposure voltage Ex is a value indicated by the symbol Vx in FIG. 9(b).

手動モードでは、上記電圧Ｖｘのもとに原稿に応じたオ
ペレータの判断によシ、直線２４ご示す特性に従りて露
光電圧が適宜調節される。In the manual mode, the exposure voltage is appropriately adjusted based on the voltage Vx and according to the characteristics shown by the straight line 24, depending on the operator's judgment depending on the document.

ここで仮に、手動モードにおける標準露光電圧ＥＸを自
動モードにおｈてそのまま固定露光電圧とし、且つ自動
モードのもとて可変の現像バイアス電圧の特性を上記手
動モード時の固定現像バイアス電圧ＶＸを含む直線２５
の特性に従う様に変化させるものとすると、次の不都合
を生ずる。Here, suppose that the standard exposure voltage EX in manual mode is changed to the fixed exposure voltage in automatic mode, and the characteristic of the variable developing bias voltage in automatic mode is changed to the fixed developing bias voltage VX in manual mode. 25 straight lines including
If it is changed so as to follow the characteristics of , the following inconvenience will occur.

自動モードにおいては、現像バイアス電圧のみが可変で
あるからこれだけで画像濃度を調節しようとすると、標
準原稿の地肌濃度範囲０．０７〜０．３５の地肌を抜く
には、現像バイアス電圧として最大５００Ｖ必要であり
、そのように設定すると、前記第８図に即して説明した
如く、原稿黒部の濃度を１．０以上とすることができな
（なり、結局コントラストを得ることができなくなる。In automatic mode, only the developing bias voltage is variable, so if you try to adjust the image density using only this, the maximum developing bias voltage will be 500 V to remove the background density range of standard originals from 0.07 to 0.35. If this setting is made, the density of the black portion of the document cannot be made greater than 1.0 (as explained above with reference to FIG. 8), and as a result, no contrast can be obtained.

このようなことをなくするには、自動モードに切換えた
ときに、標準原稿の地肌の濃度範囲（０，０７〜０．３
５）でも現像バイアス電圧を４００ｖ以下となし得るよ
うに標準露光電圧Ｅｘよりもステ、ブアップした値を固
定電圧として設定する。そのような固定の露光電圧値を
ＥＸＩとすれば、この固定露光電圧値ＥＸＩの下におけ
る現像バイアス電圧の特性は第９図（ｂ）Ｋ符号２６で
示す通りであり、比較的濃い地肌を抜くための現像バイ
アス電圧でも、４００Ｖ未満となって、地肌を抜き得る
と共に十分なコントラストも得ることができる。To eliminate this problem, when switching to automatic mode, set the background density range (0.07 to 0.3
In 5), a value stepped up from the standard exposure voltage Ex is set as the fixed voltage so that the developing bias voltage can be 400 V or less. If such a fixed exposure voltage value is EXI, the characteristics of the developing bias voltage under this fixed exposure voltage value EXI are as shown by K symbol 26 in FIG. 9(b), and the relatively dark background can be extracted. Even if the developing bias voltage is less than 400 V, the background can be removed and sufficient contrast can be obtained.

従って、自動モードでは現像バイアス電圧の変化だけで
画像濃度を制御できることとなり、原稿濃度検出のだめ
の所謂、プレスキャンが不要となる利点がある◎ 因に、現像バイアス電圧を変化させるのに必要なデータ
を得るだめの原稿濃度、（地肌）測定は、第７図におい
て光学スキャナー２１の助走距離ａをホームポジシ四ン
における反射板５による露光光の集光位置Ｂ１から原稿
先端位置８２までの距離とし、第１０図において感光体
ドラム３の周面上、原稿先端に対応する光像位置から現
像ローラ２４までの距離をｂとすれば、原稿濃度検知の
可能な（ａ＋ｂ）の距離の間で行なわれる。Therefore, in automatic mode, the image density can be controlled simply by changing the developing bias voltage, which has the advantage of eliminating the need for so-called pre-scanning, which is the only way to detect the original density. Incidentally, the data required to change the developing bias voltage is To measure the density of the original (background) in order to obtain the desired density, the approach distance a of the optical scanner 21 in FIG. In FIG. 10, if b is the distance from the optical image position corresponding to the leading edge of the document to the developing roller 24 on the circumferential surface of the photosensitive drum 3, then the detection is performed within the distance (a+b) where the document density can be detected. It will be done.

従って、上記の距離（ａ＋ｂ　）の間で濃度検知を行な
い、この検出データに基づいて演算処理を行ない、静電
潜像の先端位置が現像ローラ２４に移動する前に適切な
現像バイアス電圧を設定して現像プロセスを実行すれば
よい。Therefore, density detection is performed between the above distance (a+b), arithmetic processing is performed based on this detected data, and an appropriate developing bias voltage is set before the leading edge position of the electrostatic latent image moves to the developing roller 24. Then, the developing process can be performed.

（効　果） 本発明では固定露光光量を大きく設定することによシ、
地肌の濃い原稿についても地肌汚れな（かつ、黒部との
間に十分なコントラストを有する記録画像を得ることが
でき好都合である。(Effect) In the present invention, by setting a large fixed exposure light amount,
This is advantageous in that even for originals with dark backgrounds, it is possible to obtain recorded images with a clean background (and sufficient contrast with black areas).

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は各露光電圧において原稿画像濃度と潜像電位と
の関係を説明した特性図、第２図は本発明を適用した電
子写真複写機の構成図、第３図は同上図の電子写真複写
機の操作スイッチの一部を示した正面図、第４図は画像
濃度調整プロセスを説明した流れ図、第５図は同上図を
補足した手動モードにおける処理プロセスの説明図、第
６図は第４図を補足した自動モードにおける処理プロセ
スの説明図、第７図は光学スキャナーユニット及びその
近傍部の部分断面図、第９図は任意の露光電圧の下にお
ける現像バイアス電圧と複写像黒部との関係を説明した
図、第９図は画像濃度調整に係る諸因子の関係を説明し
た図、第１０図は感光体ドラム上における潜像位置と現
像ローラとの関係を説明した図である。 悌　１　図 悌す図 俤２図 ｔ 俤　５　図 俤石図 俤７図　　　覚１０図Figure 1 is a characteristic diagram explaining the relationship between original image density and latent image potential at each exposure voltage, Figure 2 is a configuration diagram of an electrophotographic copying machine to which the present invention is applied, and Figure 3 is an electrophotograph of the same figure as above. FIG. 4 is a flowchart explaining the image density adjustment process; FIG. 5 is a supplementary diagram of the processing process in manual mode; FIG. An explanatory diagram of the processing process in automatic mode supplementing Figure 4, Figure 7 is a partial cross-sectional view of the optical scanner unit and its vicinity, and Figure 9 shows the relationship between the developing bias voltage and the black part of the copied image under an arbitrary exposure voltage. FIG. 9 is a diagram explaining the relationship between various factors related to image density adjustment, and FIG. 10 is a diagram explaining the relationship between the latent image position on the photosensitive drum and the developing roller. 1 fig. 2 fig. t 5 fig. stone fig. 7 fig.

Claims (1)

【特許請求の範囲】 １、原稿情報に基づき、現像バイアスを変化させて自動
的に画像調整を行なう画像形成装置において、 通常画調の原稿の中、地肌濃度が高いものに対し、該地
肌部が所望の複写濃度になる様に現像バイアスを高めた
場合にも複写画像のコントラストが損なわれない様に露
光光量を設定することを特徴とする画像形成方法。 ２、特許請求の範囲第１項記載の画像形成装置は、原稿
画像濃度情報に基づき現像バイアスや露光光量を自動的
に変化させて画像調整を行なう自動調整モードと、手動
により露光光量を変化させて画像調整を行なう手動調整
モードとの相互の切換えが任意に選択自在であることを
特徴とする画像形成方法。[Scope of Claims] 1. In an image forming apparatus that automatically adjusts an image by changing a developing bias based on document information, for a document with a high background density among documents with normal image tone, An image forming method characterized in that the amount of exposure light is set so that the contrast of a copied image is not impaired even when a developing bias is increased so that a desired copy density is obtained. 2. The image forming apparatus according to claim 1 has an automatic adjustment mode in which image adjustment is performed by automatically changing the developing bias and exposure light amount based on document image density information, and an automatic adjustment mode in which image adjustment is performed by automatically changing the developing bias and exposure light amount based on document image density information, and an automatic adjustment mode in which image adjustment is performed by automatically changing the developing bias and exposure light amount based on document image density information. An image forming method characterized in that switching between a manual adjustment mode and a manual adjustment mode in which image adjustment is performed can be arbitrarily selected.
JP59209065A 1984-10-05 1984-10-05 Forming method of picture Pending JPS6187172A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59209065A JPS6187172A (en) 1984-10-05 1984-10-05 Forming method of picture

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59209065A JPS6187172A (en) 1984-10-05 1984-10-05 Forming method of picture

Publications (1)

Publication Number Publication Date
JPS6187172A true JPS6187172A (en) 1986-05-02

Family

ID=16566667

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59209065A Pending JPS6187172A (en) 1984-10-05 1984-10-05 Forming method of picture

Country Status (1)

Country Link
JP (1) JPS6187172A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8953010B2 (en) 2011-12-02 2015-02-10 Sharp Kabushiki Kaisha Light scanning device and image forming apparatus

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5436725A (en) * 1977-08-26 1979-03-17 Ricoh Co Ltd Zerographic copying method
JPS5794757A (en) * 1980-12-03 1982-06-12 Ricoh Co Ltd Copy density adjusting device
JPS5915264A (en) * 1982-07-19 1984-01-26 Konishiroku Photo Ind Co Ltd Picture control device of copying machine
JPS59135482A (en) * 1983-01-22 1984-08-03 Canon Inc Image forming device

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JPS5436725A (en) * 1977-08-26 1979-03-17 Ricoh Co Ltd Zerographic copying method
JPS5794757A (en) * 1980-12-03 1982-06-12 Ricoh Co Ltd Copy density adjusting device
JPS5915264A (en) * 1982-07-19 1984-01-26 Konishiroku Photo Ind Co Ltd Picture control device of copying machine
JPS59135482A (en) * 1983-01-22 1984-08-03 Canon Inc Image forming device

Cited By (1)

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Publication number Priority date Publication date Assignee Title
US8953010B2 (en) 2011-12-02 2015-02-10 Sharp Kabushiki Kaisha Light scanning device and image forming apparatus

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