JPH04110970A - Image forming device - Google Patents
Image forming deviceInfo
- Publication number
- JPH04110970A JPH04110970A JP2230811A JP23081190A JPH04110970A JP H04110970 A JPH04110970 A JP H04110970A JP 2230811 A JP2230811 A JP 2230811A JP 23081190 A JP23081190 A JP 23081190A JP H04110970 A JPH04110970 A JP H04110970A
- Authority
- JP
- Japan
- Prior art keywords
- image
- bias voltage
- developing bias
- toner
- density
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 108091008695 photoreceptors Proteins 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 4
- 238000001514 detection method Methods 0.000 abstract description 11
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 230000007423 decrease Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Landscapes
- Developing For Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
- Control Or Security For Electrophotography (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、複写装置、プリンタ等の二成分現像装置を具
備した画像形成装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus equipped with a two-component developing device, such as a copying machine or a printer.
感光体上に静電潜像を形成し、該潜像を現像剤により可
視像化し、可視像化された像を転写材に転写し、定着さ
せることにより画像形成を行う画像形成装置は広く知ら
れている。An image forming apparatus that forms an electrostatic latent image on a photoreceptor, visualizes the latent image using a developer, transfers the visualized image to a transfer material, and fixes it to form an image. widely known.
従来の電子写真複写機では、一般にユーザーが任意の画
像濃度を選択できるように、操作パネル上に画像濃度調
整装置(ボタン、レバー等)が設置されている。この画
像濃度調整機構により、画像濃度を濃くするために、ラ
ンプ電圧を低くするように露光ランプ電圧を制御するか
、現像バイアス電圧を低くするように現像バイアス電圧
を制御することが行われている。In conventional electrophotographic copying machines, an image density adjustment device (button, lever, etc.) is generally installed on the operation panel so that the user can select an arbitrary image density. With this image density adjustment mechanism, in order to increase the image density, the exposure lamp voltage is controlled to lower the lamp voltage, or the developing bias voltage is controlled to lower the developing bias voltage. .
上記の画像濃度調整は現像装置内の現像剤のトナー濃度
の高低にかかわらず、常に実施できる状態にある。The above-mentioned image density adjustment can always be carried out regardless of the level of toner concentration of the developer in the developing device.
ところで、二成分現像剤を用いた電子写真複写機におい
て、現像剤のキャリアが現像されて、転写剤に付着する
という現象がある。By the way, in an electrophotographic copying machine using a two-component developer, there is a phenomenon in which the carrier of the developer is developed and adheres to the transfer agent.
特に、トナー濃度の低い時、現像バイアス電圧が高いと
、現像ローラと感光体の間に逆電界が生じてこのキャリ
ア付着が発生しやすくなる。キャリア付着が発生すると
、感光体と転写材の密着不良により転写、定着不良が発
生するだけでなく、感光体、定着ローラ、クリーニング
ブレード等にもキズ発生等の悪影響を及ぼす。Particularly, when the toner concentration is low and the developing bias voltage is high, a reverse electric field is generated between the developing roller and the photoreceptor, which tends to cause carrier adhesion. When carrier adhesion occurs, it not only causes transfer and fixing failure due to poor adhesion between the photoreceptor and the transfer material, but also has an adverse effect on the photoreceptor, fixing roller, cleaning blade, etc., such as the occurrence of scratches.
感光体上の画像間の非画像部に対する現像ローラバイア
ス電圧を、感光体上の画像部に対する値よりも低くなる
ように切り換えることにより、非画像部へのキャリアの
付着および画像背景部へのトナーの付着を防止すること
が、例えば特開昭6(1−6966号公報により知られ
ているが、トナー濃度の変化によるキャリア付着の問題
については考慮されていない。By switching the developing roller bias voltage for the non-image area between images on the photoreceptor so that it is lower than the value for the image area on the photoreceptor, carrier adhesion to the non-image area and toner to the image background area can be reduced. It is known, for example, from Japanese Unexamined Patent Publication No. 1-6966, to prevent the adhesion of carriers, but the problem of carrier adhesion due to changes in toner concentration is not considered.
〔発明が解決しようとする課題]
本発明は、従来の上記の問題を解消し、トナー濃度が低
下してもキャリア付着を生しない画像形成装置を提供す
ることを課題とする。[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned conventional problems and provide an image forming apparatus that does not cause carrier adhesion even when the toner concentration decreases.
本発明は、上記の課題を、感光体上に静電潜像を形成し
、該潜像を現像剤により可視像化し、可視像化された像
を転写材に転写し、定着させることにより画像形成を行
う画像形成装置において、現像剤のトナー濃度を検出す
るトナー濃度センサと、現像バイアス電圧を制御する制
御手段とを備え、前記トナー濃度センサで検出された検
出値によって、調整画像濃度に関する上記現像バイアス
電圧の可変範囲の限界値を変えることを特徴とする画像
形成装置に礪り解決した。The present invention solves the above problem by forming an electrostatic latent image on a photoreceptor, making the latent image visible using a developer, and transferring the visualized image to a transfer material and fixing it. An image forming apparatus that performs image formation includes a toner density sensor that detects the toner density of a developer and a control unit that controls a developing bias voltage, and adjusts the adjusted image density based on the detected value detected by the toner density sensor. The problem was solved by an image forming apparatus characterized by changing the limit value of the variable range of the developing bias voltage.
〔作用]
本発明により、トナー濃度センサで現像剤のトナー濃度
を検出し、検出した値によって現像バイアス電圧の可変
範囲を設定する。例えばトナー濃度が低いと検知した時
に、現像バイアス電圧の可変範囲内で上限の値を低く設
定することによりユーザーの誤操作等で画像濃度調整を
“明る目″すなわち現像バイアス電圧を高目にセットし
てもキャリア付着が発生しないようにする。[Operation] According to the present invention, the toner concentration of the developer is detected by the toner concentration sensor, and the variable range of the developing bias voltage is set based on the detected value. For example, when it is detected that the toner density is low, by setting the upper limit value within the variable range of the developing bias voltage low, the image density adjustment may be set to "bright", that is, the developing bias voltage may be set to a high value due to user error. Prevent carrier adhesion from occurring.
本発明の詳細を図に示す実施例に基づいて説明する。 The details of the present invention will be explained based on embodiments shown in the drawings.
第1図は本発明に係るトナー濃度センサ及び現像バイア
ス電圧制御装置を実装してなる電子写真複写機の構成を
概念的に示したものであり、プラテンガラス1を支持す
るプラテンサポート2にトナー濃度検知用パターン3が
設けられる。原稿を照明する光源ランプ4によりトナー
濃度検知用パターン3が照明される。FIG. 1 conceptually shows the structure of an electrophotographic copying machine equipped with a toner concentration sensor and a developing bias voltage control device according to the present invention. A detection pattern 3 is provided. The toner density detection pattern 3 is illuminated by a light source lamp 4 that illuminates the original.
まず複写のための前段階としてプラテンガラス1上の複
写すべき原稿1日の載置が完了し、コピーサイクルの動
作指令がなされると光源ランプ4が点灯され、最初にプ
ラテンサポート2の下に配置されたトナー濃度検知用パ
ターン(以下パターンと称する)3の走査が行われる。First, as a preliminary step for copying, the original to be copied for the first day has been placed on the platen glass 1, and when a copy cycle operation command is issued, the light source lamp 4 is turned on, and the original is placed under the platen support 2. The arranged toner density detection pattern (hereinafter referred to as pattern) 3 is scanned.
このパターン3は、基準濃度を有する反射板からなり、
その走査光はミラー5、レンズ6、ミラー7の光学系を
通して帯電チャージ中10によって帯電された感光体8
上に静電潜像を形成する。パターン3の静電潜像は次い
で現像器9により現像され、所定濃度のトナーが吸着さ
れたパターン像となり、前記感光体8の周回に伴って転
写、分離チャージ中12、トナー濃度センサ13上を順
次通過する。This pattern 3 consists of a reflector having a standard density,
The scanning light passes through an optical system of a mirror 5, a lens 6, and a mirror 7 to a photoreceptor 8 charged by a charging member 10.
forming an electrostatic latent image thereon. The electrostatic latent image of the pattern 3 is then developed by the developing device 9 to become a pattern image with toner of a predetermined density adsorbed, which is transferred as the photoreceptor 8 rotates, and is transferred onto the toner density sensor 13 during separation charging 12. Pass sequentially.
このパターン像の通過位置上に配置されるもののうち、
前記トナー濃度センサ13は、例えば前記感光体8の表
面に所定光量の光を照射する発光素子と、その反射光を
受光する受光素子から成り、当該受光素子により受光さ
れた光をその受光量に応じた電気信号に変換して出力す
る。このトナー濃度センサ13の光電変換出力は濃度検
出回路15に入力され、該入力レベルに応じた濃度信号
として検出される。従って前記濃度検出回路15の検出
値は、前記パターン像の濃度を示すことになる。次いで
前記濃度検出回路15の検出濃度信号は制御回路16へ
入力され、ここで当該制御回路16は前記パターン像の
検出濃度にもとづき電源供給回路17から現像器9への
現像バイアス供給電圧の設定を行う、一方前記トナー濃
度センサ13上を通過したパターン像はその後通過する
クリニング14によって当該怒光体8上から完全に消去
される。斯かる処理のなされた前記感光体8は引き続き
駆動されて次のコピーサイクルのための周回に入り、こ
の回のコピーサイクルの最初の動作としてその表面に対
する帯電工程が実行される。またこのコピーサイクルの
開始に伴い前記走査光学系では、前記ミラー5、レンズ
6、ミラー7を通して上記帯電工程後の感光体8上に露
光される。該露光により、前記感光体8上に形成された
静電潜像は、次に現像器9によって現像されトナー像化
される。斯かるタイミングで前記制御回路16では前記
パターン像の濃度に応して、予め設定しておいた電圧値
にもとづき、前記電源供給回路17から現像器9の現像
ローラへの供給制御を開始し、現像バイアス電圧を印加
する。Among those placed on the passing position of this pattern image,
The toner concentration sensor 13 includes, for example, a light emitting element that irradiates the surface of the photoreceptor 8 with a predetermined amount of light, and a light receiving element that receives the reflected light, and converts the light received by the light receiving element into the received light amount. It converts into a corresponding electrical signal and outputs it. The photoelectric conversion output of the toner density sensor 13 is input to a density detection circuit 15, and detected as a density signal according to the input level. Therefore, the detection value of the density detection circuit 15 indicates the density of the pattern image. Next, the detected density signal of the density detection circuit 15 is input to the control circuit 16, and the control circuit 16 sets the developing bias supply voltage from the power supply circuit 17 to the developing device 9 based on the detected density of the pattern image. On the other hand, the pattern image that has passed on the toner density sensor 13 is completely erased from the photosensitive body 8 by the cleaning 14 that passes thereafter. The photoreceptor 8 that has been subjected to such treatment is continuously driven and begins to rotate for the next copy cycle, and as the first operation of this copy cycle, a charging process is performed on the surface of the photoreceptor 8. At the start of this copy cycle, the scanning optical system exposes the photoreceptor 8 that has undergone the charging process through the mirror 5, lens 6, and mirror 7. The electrostatic latent image formed on the photoreceptor 8 by the exposure is then developed by a developing device 9 to form a toner image. At this timing, the control circuit 16 starts controlling the supply from the power supply circuit 17 to the developing roller of the developing device 9 based on a preset voltage value according to the density of the pattern image, Apply developing bias voltage.
−船釣に前述の現像工程では、前記感光体8の表面電位
と、現像ローラに印加された現像バイアス電圧の電位差
により、現像ローラ表面のトナー粒子(+)が前記感光
体8に静電吸着するが、現像剤のトナー濃度が低くなる
につれて、高い現像バイアス電圧を印加した際に、前記
感光体8の非画像部と現像ローラの間隙に逆電界が生し
、キャリア粒子(−)が前記感光体8に静電吸着してし
まう。- In the above-mentioned developing process, the toner particles (+) on the surface of the developing roller are electrostatically attracted to the photoconductor 8 due to the potential difference between the surface potential of the photoconductor 8 and the developing bias voltage applied to the developing roller. However, as the toner concentration of the developer decreases, when a high developing bias voltage is applied, a reverse electric field is generated in the gap between the non-image area of the photoreceptor 8 and the developing roller, and the carrier particles (-) are It is electrostatically attracted to the photoreceptor 8.
そこで、本実施例では、トナー濃度に対応して現像バイ
アス電圧を次のように設定する。Therefore, in this embodiment, the developing bias voltage is set in accordance with the toner density as follows.
通常の制御レベルのトナー濃度の時は、第2図に示す操
作パネル上の画像濃度調整装!20のボタン操作により
濃度ステップ表示目盛り21で所望の濃度を選定し、露
光ラランプ電圧及び現像ノ\イアス電圧を表1及び第3
図及び第4図に示すように濃度に応して設定して、任意
の画像濃度が得られるようにする。When the toner density is at the normal control level, the image density adjustment device on the operation panel shown in Figure 2! Select the desired density on the density step display scale 21 by operating the button 20, and then set the exposure lamp voltage and development current voltage as shown in Tables 1 and 3.
As shown in the figure and FIG. 4, settings are made according to the density so that an arbitrary image density can be obtained.
表 1
第3図は横軸にノツチを縦軸にバイアス電圧を示し、第
4図は横軸にノツチを、縦軸はランプ電圧を示す。Table 1 In FIG. 3, the horizontal axis shows the notch, and the vertical axis shows the bias voltage, and in FIG. 4, the horizontal axis shows the notch, and the vertical axis shows the lamp voltage.
トナーニアエンドやトナーエンド(低トナー濃度)を検
知した時は、表2及び第5図に示すようにノツチ6.7
に対応するバイアス電圧の絶対値を下げる0図で横軸は
ノツチを、縦軸はバイアス電圧を示す。When toner near-end or toner end (low toner density) is detected, turn the notch 6.7 as shown in Table 2 and Figure 5.
In the diagram, the horizontal axis shows the notch and the vertical axis shows the bias voltage.
表 2
第5図では一点鎖線はa≦v、、<bの場合の現像バイ
アス電圧を実線はb<v、、の場合の現像バイアス電圧
を示すeV!Fはトナー濃度センサの出力を示す。Table 2 In Fig. 5, the dashed line indicates the developing bias voltage when a≦v, , <b, and the solid line indicates the developing bias voltage when b<v, eV! F indicates the output of the toner concentration sensor.
ノツチ6及び7の現像バイアス電圧を通常の第3図に示
す電圧よりも低い電圧に設定して、キャリア付着の発生
を防止する。第6図はトナー濃度、トナー濃度センサ出
力及び現像バイアス電圧の関係を示す、トナー濃度が低
下するとAとBを境にして、現像バイアス電圧を例えば
ノツチ6では240Vから一200Vに、ノツチ7では
一280■から一240■に、更に一200■に低下す
る低下する。自回に示す実施例では、感光体を(−)帯
電させる電子写真複写機に関する。The developing bias voltages of the notches 6 and 7 are set to a voltage lower than the normal voltage shown in FIG. 3 to prevent carrier adhesion. FIG. 6 shows the relationship between toner concentration, toner concentration sensor output, and developing bias voltage. When the toner concentration decreases, the developing bias voltage is changed from 240 V to -200 V for notch 6, for example, from 240 V to -200 V for notch 7, and It decreases from -280■ to -1240■ and further to -1200■. The embodiment shown here relates to an electrophotographic copying machine in which a photoreceptor is charged (-).
コピーサイクル開始直後のデッドサイクル中にパターン
像の濃度を検出する手段は、例えばトナー濃度制御を現
像剤の透磁率を検知して行うセンサー等の構成要素とし
て既設されている機種もあり、これを兼用することで構
成の簡略化を図ることもできる。Some models already have a means for detecting the density of the pattern image during the dead cycle immediately after the start of the copy cycle as a component such as a sensor that controls toner density by detecting the magnetic permeability of the developer. By using the same function, the configuration can be simplified.
本発明により、画像形成装置においては、現像剤のトナ
ー濃度に応じて、現像時に現像ローラに印加するバイア
ス電圧の画像濃度調整装置によって可変できる範囲を規
制するので、ユーザーの誤操作等による異常画像の発生
、例えば低トナー濃度時に高バイアス電圧を印加した時
に発生するキャリア付着の発生を防止することができる
。According to the present invention, in an image forming apparatus, the range that can be varied by the image density adjustment device of the bias voltage applied to the developing roller during development is regulated according to the toner density of the developer. For example, carrier adhesion that occurs when a high bias voltage is applied at a low toner concentration can be prevented.
第1図は本発明に係る画像形成装置の概略説明図、第2
図は操作パ茅ル上の画像濃度調整装置を示す略図、第3
凹は画像濃度調整時の現像バイアス電圧の可変範囲を示
す図、第4図は露光ランプ電圧の可変範囲を示す図、第
5図は濃度低下時の現像バイアス電圧の可変範囲の限界
値の変化を示す図、第6図はトナー濃度と現像バイアス
電圧の関係を示す図である。
】・・・コンタクトガラス
3・・・トナー濃度検知用パターン
4・・・光源ランプ
9・・・現像器
13・・・トナー濃度センサ
15・・・トナー濃度検知回路
第3
(ノッ斗つFIG. 1 is a schematic explanatory diagram of an image forming apparatus according to the present invention, and FIG.
The figure is a schematic diagram showing the image density adjustment device on the operation panel.
The depression shows the variable range of the developing bias voltage when adjusting the image density, Figure 4 shows the variable range of the exposure lamp voltage, and Figure 5 shows the change in the limit value of the variable range of the developing bias voltage when the density decreases. FIG. 6 is a diagram showing the relationship between toner density and developing bias voltage. ]...Contact glass 3...Toner density detection pattern 4...Light source lamp 9...Developer 13...Toner density sensor 15...Toner density detection circuit 3rd
Claims (1)
視像化し、可視像化された像を転写材に転写し、定着さ
せることにより画像形成を行う画像形成装置において、
現像剤のトナー濃度を検出するトナー濃度センサと、現
像バイアス電圧を制御する制御手段とを備え、前記トナ
ー濃度センサで検出された検出値によって、調整画像濃
度に関する上記現像バイアス電圧の可変範囲の限界値を
変えることを特徴とする画像形成装置。In an image forming apparatus that forms an electrostatic latent image on a photoreceptor, visualizes the latent image with a developer, transfers the visualized image to a transfer material, and fixes it to form an image. ,
It includes a toner density sensor that detects the toner density of the developer and a control means that controls a developing bias voltage, and the limit of the variable range of the developing bias voltage regarding the adjusted image density is determined based on the detected value detected by the toner density sensor. An image forming device characterized by changing values.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2230811A JP3016580B2 (en) | 1990-08-31 | 1990-08-31 | Image forming device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2230811A JP3016580B2 (en) | 1990-08-31 | 1990-08-31 | Image forming device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04110970A true JPH04110970A (en) | 1992-04-13 |
JP3016580B2 JP3016580B2 (en) | 2000-03-06 |
Family
ID=16913646
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2230811A Expired - Fee Related JP3016580B2 (en) | 1990-08-31 | 1990-08-31 | Image forming device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP3016580B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005128514A (en) * | 2003-10-23 | 2005-05-19 | Samsung Electronics Co Ltd | Electrophotographic image forming apparatus and print density control method for it |
US8488984B2 (en) | 2010-03-19 | 2013-07-16 | Sharp Kabushiki Kaisha | Toner concentration controller and image forming apparatus including the toner concentration controller |
-
1990
- 1990-08-31 JP JP2230811A patent/JP3016580B2/en not_active Expired - Fee Related
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005128514A (en) * | 2003-10-23 | 2005-05-19 | Samsung Electronics Co Ltd | Electrophotographic image forming apparatus and print density control method for it |
US8488984B2 (en) | 2010-03-19 | 2013-07-16 | Sharp Kabushiki Kaisha | Toner concentration controller and image forming apparatus including the toner concentration controller |
Also Published As
Publication number | Publication date |
---|---|
JP3016580B2 (en) | 2000-03-06 |
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