JP3012742B2 - Electrophotographic equipment - Google Patents
Electrophotographic equipmentInfo
- Publication number
- JP3012742B2 JP3012742B2 JP4234611A JP23461192A JP3012742B2 JP 3012742 B2 JP3012742 B2 JP 3012742B2 JP 4234611 A JP4234611 A JP 4234611A JP 23461192 A JP23461192 A JP 23461192A JP 3012742 B2 JP3012742 B2 JP 3012742B2
- Authority
- JP
- Japan
- Prior art keywords
- unit
- developing
- voltage
- power supply
- transfer
- 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
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- Dry Development In Electrophotography (AREA)
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、電子写真プロセスによ
り画像の記録を行う電子写真装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus for recording an image by an electrophotographic process.
【０００２】[0002]
【従来の技術】図６は従来の電子写真装置の概略構成を
示す図である。図中、１は感光ドラムである。この感光
ドラム１の周辺にはその周面に沿って、帯電装置２、露
光装置３、現像装置４、転写装置５およびクリーニング
装置６が設けられている。2. Description of the Related Art FIG. 6 is a diagram showing a schematic configuration of a conventional electrophotographic apparatus. In the figure, reference numeral 1 denotes a photosensitive drum. Around the photosensitive drum 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are provided along the peripheral surface.
【０００３】この電子写真装置では、帯電装置２によっ
て例えば−５００Ｖに帯電された感光ドラム１の感光面
を露光装置３によって記録すべき画像に応じて露光し、
静電潜像を形成する。そして、この感光ドラム１の感光
面に形成された静電潜像の現像を現像装置４で行う。現
像装置４は、現像スリーブ４１に感光ドラム１の帯電電
位と同極性に帯電したトナーを担持し、このトナーを感
光ドラム１に接触させる。現像スリーブ４１には現像バ
イアス電源４２から感光ドラム１の帯電電位と同極性か
つ低電圧（例えば−２００Ｖ）な現像バイアスを印加し
てあり、静電潜像と現像バイアスとの作用により、感光
ドラム１に選択的にトナーを付着させる。すなわち、感
光ドラム１上の帯電部分には、感光ドラム１側が高電位
であるためにトナーが付着せず、また露光され除電され
た部分には、感光ドラム１側が低電位であるためにトナ
ーが付着する。In this electrophotographic apparatus, a photosensitive surface of a photosensitive drum 1 charged to, for example, -500 V by a charging device 2 is exposed by an exposure device 3 in accordance with an image to be recorded.
An electrostatic latent image is formed. Then, the developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photosensitive drum 1. The developing device 4 carries a toner charged to the same polarity as the charged potential of the photosensitive drum 1 on the developing sleeve 41, and brings the toner into contact with the photosensitive drum 1. A developing bias having the same polarity as the charging potential of the photosensitive drum 1 and a low voltage (for example, -200 V) is applied to the developing sleeve 41 from a developing bias power supply 42, and the photosensitive drum is operated by the action of the electrostatic latent image and the developing bias. 1 is made to adhere toner selectively. That is, no toner adheres to the charged portion on the photosensitive drum 1 because the photosensitive drum 1 has a high potential, and toner does not adhere to the exposed and neutralized portion because the photosensitive drum 1 has a low potential. Adhere to.
【０００４】次に、感光ドラム１の感光面に記録紙Ｐを
重ねる。そして、感光ドラム１に付着したトナーを転写
装置５より記録紙Ｐに転写する。転写装置５は、感光ド
ラム１に当接され、感光ドラム１との間に記録紙Ｐを挟
持する転写ローラ５１と、この転写ローラ５１にトナー
の帯電電荷と逆極性の電圧（例えば＋５００Ｖ）を与え
る転写電源５２とからなり、転写電源５２で発生したト
ナーと逆極性の電圧を転写ローラ５１を介して記録紙Ｐ
の背面に与えることによって、前記感光ドラム１の感光
面に付着したトナーを記録紙へと転写する。その後、感
光ドラム１の感光面は、記録紙が剥離された後、転写さ
れずに残留しているトナーがクリーニング装置６で除去
される。Next, the recording paper P is overlaid on the photosensitive surface of the photosensitive drum 1. Then, the toner attached to the photosensitive drum 1 is transferred to the recording paper P by the transfer device 5. The transfer device 5 is in contact with the photosensitive drum 1 and holds the recording paper P between the transfer roller 51 and the transfer roller 51. The transfer roller 51 applies a voltage (for example, +500 V) having a polarity opposite to the charge of the toner to the transfer roller 51. And a transfer power supply 52 for applying a voltage having a polarity opposite to that of the toner generated by the transfer power supply 52 via the transfer roller 51 to the recording paper P.
To transfer the toner adhered to the photosensitive surface of the photosensitive drum 1 onto recording paper. Thereafter, the toner remaining on the photosensitive surface of the photosensitive drum 1 without being transferred is removed by the cleaning device 6 after the recording paper is peeled off.
【０００５】ところで以上のように構成された電子写真
装置において、動作停止時に着目すると、感光ドラム１
表面の電位は不定となっている。このように感光ドラム
１の電位が不定である状態では、記録開始時において現
像装置４の位置を通過する際に、電位が低くなっている
部分ではトナーが付着してしまう。In the electrophotographic apparatus configured as described above, when attention is paid to the operation stop, the photosensitive drum 1
The surface potential is undefined. In the state where the potential of the photosensitive drum 1 is indefinite as described above, when passing through the position of the developing device 4 at the start of recording, toner adheres to a portion where the potential is low.
【０００６】そこで、感光ドラム１の回転を開始すると
同時に帯電装置２による帯電を開始し、感光ドラム１表
面の電位が不定となっている部分を可能な限り小さくし
ている。Accordingly, the charging by the charging device 2 is started at the same time as the rotation of the photosensitive drum 1 is started, so that the portion of the surface of the photosensitive drum 1 where the potential is unstable is made as small as possible.
【０００７】しかし、感光ドラム１の停止時に帯電装置
２での帯電位置（図６中のＡ点）と現像装置４での現像
位置（図６中のＢ点）との間は帯電させることができ
ず、この部分（図６中にイで示す部分）にトナーが付着
することを防止することができない。このような感光ド
ラム１へのトナーの付着が生じると、感光ドラム１に付
着したトナーはクリーニング装置６で回収されて廃トナ
ーとなるため、トナーの浪費となる。また転写装置５に
ローラやブラシのような接触式のものを用いた場合に
は、感光ドラム１に付着したトナーが転写装置にまで付
着してしまい、記録紙の背面を汚してしまったり、また
転写効率が低下して転写不良を起こしてしまうという不
具合があった。However, when the photosensitive drum 1 is stopped, charging can be performed between the charging position of the charging device 2 (point A in FIG. 6) and the developing position of the developing device 4 (point B in FIG. 6). Therefore, it is impossible to prevent toner from adhering to this portion (the portion indicated by a in FIG. 6). When toner adheres to the photosensitive drum 1 as described above, the toner adhered to the photosensitive drum 1 is collected by the cleaning device 6 and becomes waste toner, so that the toner is wasted. Further, when a contact type device such as a roller or a brush is used as the transfer device 5, the toner adhered to the photosensitive drum 1 adheres to the transfer device, and stains the back surface of the recording paper. There has been a problem that the transfer efficiency is lowered to cause transfer failure.
【０００８】[0008]
【発明が解決しようとする課題】以上のように従来の電
子写真装置は、記録動作の開始時において、停止時に帯
電位置と現像位置との間に位置していた感光体上の部分
が電位不定となっているため、この部分に多量の現像剤
付着が生じるという不具合があった。As described above, in the conventional electrophotographic apparatus, at the start of the recording operation, the portion on the photoreceptor located between the charging position and the developing position at the time of the stop is indeterminate in potential. Therefore, there is a problem that a large amount of developer adheres to this portion.
【０００９】本発明はこのような事情を考慮してなされ
たものであり、その目的とするところは、感光体への無
駄な現像剤付着を極力抑え、これにより経済的かつ高画
質に記録を行うことができる電子写真装置を提供するこ
とにある。The present invention has been made in view of such circumstances, and an object of the present invention is to minimize wasteful adhesion of a developer to a photoreceptor, thereby achieving economical and high-quality recording. An object of the present invention is to provide an electrophotographic apparatus that can perform the electrophotographic apparatus.
【００１０】[0010]
【課題を解決するための手段】本発明は、例えば感光ド
ラムなどの感光体の回転開始時に、帯電手段による前記
感光体の帯電が開始された時点に前記帯電手段の帯電位
置に位置していた前記感光体上の所定点が現像手段の現
像位置に至るのに要する時間が経過するまでは例えばス
リーブ駆動系などの担持体回転手段による例えば現像ス
リーブなどの現像剤担持体の回転駆動を停止させてお
き、こののちに前記担持体回転手段による前記現像剤担
持体の回転駆動を行わせる例えば制御部などの現像制御
手段と、前記現像剤の帯電極性と同極性の電圧を発生す
る例えば高圧電源などの第２電源手段と、前記現像剤の
帯電極性と逆極性の電圧を発生する例えば転写電源など
の第１電源手段が発生する電圧および前記第２電源手段
が発生する電圧のいずれかを前記電圧印加手段に与える
例えばスイッチなどの切換手段と、少なくとも前記感光
体の回転が開始された時点に前記現像位置に位置してい
た前記感光体上の所定点が前記転写手段の転写位置を通
過する際には前記電圧印加手段に前記第２電源手段が発
生する電圧を前記電圧印加手段に与えるよう前記切換手
段を制御する例えば制御部などの転写制御手段とを具備
した。According to the present invention, when a photosensitive member such as a photosensitive drum starts to rotate, the photosensitive member is positioned at a charging position of the charging member when charging of the photosensitive member by the charging device is started. Until the time required for the predetermined point on the photoconductor to reach the developing position of the developing means elapses, the rotation driving of the developer carrier such as the developing sleeve by the carrier rotating means such as the sleeve driving system is stopped. A developing control unit such as a control unit for rotating the developer carrier by the carrier rotating unit, and a high-voltage power supply for generating a voltage having the same polarity as the charged polarity of the developer. And a voltage generated by the first power supply such as a transfer power supply and a voltage generated by the second power supply. Switching means such as a switch for providing the voltage to the voltage applying means, and a predetermined point on the photosensitive body which is located at the developing position at least when the rotation of the photosensitive body is started is transferred by the transfer means. A transfer control unit such as a control unit for controlling the switching unit so as to apply the voltage generated by the second power supply unit to the voltage application unit when passing through the position is provided.
【００１１】[0011]
【作用】このような手段を講じたことにより、感光体の
回転開始時に、帯電手段による前記感光体の帯電が開始
された時点に前記帯電手段の帯電位置に位置していた前
記感光体上の所定点が現像手段の現像位置に至るのに要
する時間が経過するまでは現像剤担持体は回転されな
ず、当該期間には感光体への現像剤の供給がなされな
い。By taking such means, when the photosensitive member is started to rotate, the charging means starts charging the photosensitive member by the charging means. The developer carrier is not rotated until the time required for the predetermined point to reach the developing position of the developing unit elapses, and the developer is not supplied to the photoconductor during this period.
【００１２】また少なくとも前記感光体の回転が開始さ
れた時点に前記現像位置に位置していた前記感光体上の
所定点が前記転写手段の転写位置を通過する際には第２
電源手段が発生する電圧が電圧印加手段に与えられ、感
光体に付着したトナーが電圧印加手段から反発する。At least when a predetermined point on the photosensitive member located at the developing position at the time when the rotation of the photosensitive member is started passes through the transfer position of the transfer means,
The voltage generated by the power supply is applied to the voltage application unit, and the toner attached to the photoreceptor is repelled from the voltage application unit.
【００１３】[0013]
【実施例】以下、図面を参照して本発明の一実施例に付
き説明する。図１は本実施例に係る電子写真装置の要部
構成を模式的に示す図である。なお、図６と同一部分に
は同一符号を付し、その詳細な説明は省略する。An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically illustrating a main configuration of an electrophotographic apparatus according to the present embodiment. The same parts as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.
【００１４】図中、７は現像装置である。この現像装置
７は、現像スリーブ４１、現像バイアス電源４２、スリ
ーブ駆動系７１およびスイッチ７２を具備して構成され
る。現像スリーブ４１は、感光ドラム１の帯電電位と同
極性（ここでは負極性）に帯電したトナー（図示せず）
を担持し、スリーブ駆動系７１によって回転駆動されて
トナーの搬送を行う。現像スリーブ４１は感光ドラム１
に対向して配置されており、担持したトナーを感光ドラ
ム１に接触させる。現像バイアス電源４２は、感光ドラ
ム１の帯電電位と同極性（ここでは負極性）で、かつ感
光ドラム１の帯電電位（例えば−５００Ｖ）よりも低電
圧（例えば−２００Ｖ）な現像バイアスを発生し、スイ
ッチ７２を介して現像スリーブ４１に印加する。スイッ
チ７２は、現像スリーブ４１への現像バイアスの印加を
ＯＮ／ＯＦＦする。In FIG. 1, reference numeral 7 denotes a developing device. The developing device 7 includes a developing sleeve 41, a developing bias power supply 42, a sleeve driving system 71, and a switch 72. The developing sleeve 41 is a toner (not shown) charged to the same polarity (here, negative polarity) as the charged potential of the photosensitive drum 1.
And is rotated by a sleeve drive system 71 to carry the toner. The developing sleeve 41 is a photosensitive drum 1
And makes the carried toner contact the photosensitive drum 1. The developing bias power supply 42 generates a developing bias having the same polarity (here, negative polarity) as the charging potential of the photosensitive drum 1 and a voltage (for example, -200 V) lower than the charging potential of the photosensitive drum 1 (for example, -500 V). , To the developing sleeve 41 via the switch 72. The switch 72 turns on / off the application of the developing bias to the developing sleeve 41.
【００１５】８は転写装置である。この転写装置８は、
転写ローラ５１、転写電源５２、高圧電源８１およびス
イッチ８２を具備して構成される。高圧電源８１は、ト
ナーの帯電電荷と同極性の電圧、すなわち転写電源５２
が発生する電圧とは逆極性の電圧を発生する。スイッチ
８２は、転写ローラ５１への電圧供給のＯＮ／ＯＦＦお
よび供給する電圧の選択（転写電源５２が発生する電圧
および高圧電源８１が発生する電圧のいずれかの選択）
を行う。Reference numeral 8 denotes a transfer device. This transfer device 8
It comprises a transfer roller 51, a transfer power supply 52, a high-voltage power supply 81 and a switch 82. The high-voltage power supply 81 is a voltage having the same polarity as the charge of the toner, that is, the transfer power supply 52.
Generates a voltage having a polarity opposite to that of the voltage generated. The switch 82 turns ON / OFF the voltage supply to the transfer roller 51 and selects the voltage to be supplied (selection of either the voltage generated by the transfer power supply 52 or the voltage generated by the high-voltage power supply 81).
I do.
【００１６】９は感光ドラム駆動系である。この感光ド
ラム駆動系９は、例えばモータおよびギヤなどより構成
され、感光ドラム１を回転駆動する。１０は本電子写真
装置を総括的に制御する制御部である。Reference numeral 9 denotes a photosensitive drum drive system. The photosensitive drum drive system 9 includes, for example, a motor and a gear, and drives the photosensitive drum 1 to rotate. Reference numeral 10 denotes a control unit that controls the electrophotographic apparatus as a whole.
【００１７】次に以上のように構成された電子写真装置
の動作を制御部１０の制御手順に従って説明する。まず
制御部１０は、記録動作の開始時において、感光ドラム
駆動系９に対して感光ドラム１の回転駆動の開始を指示
する。これに応じ感光ドラム駆動系９は、感光ドラム１
の回転駆動を開始し、感光ドラム１が回転する（図２中
のＴ１時点）。また制御部１０は、感光ドラム駆動系９
に対して感光ドラム１の回転駆動の開始を指示するのと
同時に、帯電装置２に動作開始を指示する。帯電装置２
は、例えば周知のスコロトロン帯電器などより構成され
ており、動作開始が指示されると感光ドラム１の表面を
所定の電位（例えば−５００Ｖ）に均一帯電する。Next, the operation of the electrophotographic apparatus configured as described above will be described according to the control procedure of the control unit 10. First, at the start of the recording operation, the control unit 10 instructs the photosensitive drum drive system 9 to start rotating the photosensitive drum 1. In response to this, the photosensitive drum drive system 9 moves the photosensitive drum 1
Starts, and the photosensitive drum 1 rotates (at time T1 in FIG. 2). The control unit 10 also controls the photosensitive drum driving system 9.
At the same time as instructing the photosensitive drum 1 to start rotating, the charging device 2 is also instructed to start operation. Charging device 2
Is constituted by, for example, a well-known scorotron charger, and when the operation start is instructed, the surface of the photosensitive drum 1 is uniformly charged to a predetermined potential (for example, -500 V).
【００１８】続いて制御部１０は、Ｔ１時点から時間Ｔ
Ａ（感光ドラム１上の任意の点が帯電装置２による帯電
位置Ａから現像装置７による現像位置Ｂまで移動するの
に要する時間）が経過した時点（図２中のＴ５時点）
に、スリーブ駆動系７１に対して現像スリーブ４１の回
転駆動の開始を指示するとともに、スイッチ７２をＯＮ
する。すなわち、帯電の開始時に帯電位置Ａに位置して
いた感光ドラム１上の所定点が現像位置Ｂに到達した時
点に現像装置７の動作を開始する。これにより、現像ス
リーブ４１に現像バイアス電源４２が発生する現像バイ
アスが印加され、従来と同様な作用により現像が開始さ
れる。Subsequently, the control unit 10 determines the time T from the time T1.
A (time required for an arbitrary point on the photosensitive drum 1 to move from the charging position A by the charging device 2 to the developing position B by the developing device 7) has elapsed (time T5 in FIG. 2).
Next, the start of the rotational driving of the developing sleeve 41 is instructed to the sleeve driving system 71, and the switch 72 is turned on.
I do. That is, the operation of the developing device 7 is started when a predetermined point on the photosensitive drum 1 located at the charging position A at the time of starting charging reaches the developing position B. As a result, a developing bias generated by the developing bias power supply 42 is applied to the developing sleeve 41, and development is started by the same operation as in the related art.
【００１９】このように、記録動作の開始時においては
感光ドラム１上の電位が不定である部分が現像位置Ｂを
通過する期間には現像スリーブ４１の回転は停止状態と
しているので、当該期間には感光ドラム１の電位が不定
であっても感光ドラム１上にトナーが供給されることが
なく、感光ドラム１へのトナー付着を防止できる。As described above, at the start of the recording operation, the rotation of the developing sleeve 41 is stopped during the period in which the portion on the photosensitive drum 1 where the potential is indeterminate passes the developing position B. The toner is not supplied onto the photosensitive drum 1 even when the potential of the photosensitive drum 1 is undefined, and the toner can be prevented from adhering to the photosensitive drum 1.
【００２０】ただし、感光ドラム１の回転が停止してい
る状態において感光ドラム１と現像スリーブ４１との間
（感光ドラム１と現像スリーブ４１とのニップ部：現像
ニップ部）に位置しているトナー（現像ニップトナー）
については感光ドラム１に付着してしまうことが防止で
きない。このように感光ドラム１に付着した現像ニップ
トナーは、転写ローラ５１に付着し、さらに記録紙の背
面に付着してしまう。However, the toner located between the photosensitive drum 1 and the developing sleeve 41 (nip portion between the photosensitive drum 1 and the developing sleeve 41: developing nip portion) when the rotation of the photosensitive drum 1 is stopped. (Development nip toner)
Cannot be prevented from adhering to the photosensitive drum 1. The developing nip toner adhered to the photosensitive drum 1 adheres to the transfer roller 51 and further adheres to the back surface of the recording paper.
【００２１】このため制御部１０は、Ｔ１時点から時間
ＴＢ（感光ドラム１上の任意の点が現像位置Ｂから転写
装置８による転写位置Ｃまで移動するのに要する時間）
が経過した時点（図２中のＴ３時点）を含む所定期間
（図２中にＴＣで示す期間）に、スイッチ８２を高圧電
源８１側にＯＮする。そしてこの期間ＴＣの終了後、制
御部１０はスイッチ８２を転写電源５２側に切換える。For this reason, the control unit 10 determines the time TB from the time T1 (the time required for an arbitrary point on the photosensitive drum 1 to move from the developing position B to the transfer position C by the transfer device 8).
During a predetermined period (period indicated by TC in FIG. 2) including the point in time (T3 in FIG. 2), the switch 82 is turned on to the high voltage power supply 81 side. After the end of this period TC, the control unit 10 switches the switch 82 to the transfer power supply 52 side.
【００２２】ここで期間ＴＣは、現像ニップトナーの幅
（現像ニップ幅）および感光ドラム１と転写ローラ５１
とのニップ部（転写ニップ部）の幅（転写ニップ幅）を
考慮して、少なくとも回転停止時における現像ニップト
ナーが転写ニップ部を通過する期間に設定される。Here, the period TC is the width of the developing nip toner (developing nip width), the photosensitive drum 1 and the transfer roller 51.
In consideration of the width of the nip portion (transfer nip portion) (transfer nip width), at least a period in which the developing nip toner passes through the transfer nip portion when the rotation is stopped is set.
【００２３】具体的には、例えば現像ニップ幅および転
写ニップ幅をそれぞれ２mm、プロセススピードを３２mm
/sec、現像位置Ｂから転写位置Ｃまでの距離を２４mmと
すると、感光ドラム１の回転開始時において現像ニップ
トナーの先端が転写ニップ部に到達するのに要する時間
は約０．６８８sec となる。また現像ニップトナーが転
写ニップ部を通過するのに要する時間は０．１２５sec
となり、感光ドラム１の回転開始時において現像ニップ
トナーが転写ニップ部を通過し切るまでに要する時間は
約０．８１３sec となる。従って、スイッチ８２を高圧
電源８１側に切換えるタイミングＴ２は、Ｔ１時点から
０．６８８sec 以下の時間が経過した時点に、またスイ
ッチ８２を転写電源５２側に切換えるタイミングＴ４
は、Ｔ１時点から０．８１３sec 以上の時間が経過した
時点にそれぞれ設定される。ただしさらに具体的には、
スイッチ８２を高圧電源８１側に切換えてから転写ロー
ラ５１の電位が所定値に到達するまでには、図３に示す
ように時間ＴＤの遅れが生じる。このため好ましくは、
この遅れＴＤを考慮して、Ｔ２時点を上記よりもＴＤ分
早める。すなわちタイミングＴ２は、ＴＤを例えば０．
０５sec とすると、好ましくはＴ１時点から０．６３８
sec 以下の時間が経過した時点に設定する。Specifically, for example, the developing nip width and the transfer nip width are each 2 mm, and the process speed is 32 mm.
Assuming that the distance from the development position B to the transfer position C is 24 mm, the time required for the leading end of the development nip toner to reach the transfer nip portion at the start of rotation of the photosensitive drum 1 is about 0.688 seconds. The time required for the developing nip toner to pass through the transfer nip is 0.125 sec.
Thus, the time required for the development nip toner to completely pass through the transfer nip at the start of rotation of the photosensitive drum 1 is about 0.813 sec. Therefore, the timing T2 at which the switch 82 is switched to the high voltage power supply 81 is a timing T4 at which 0.688 sec or less has elapsed from the time T1, and the timing T4 at which the switch 82 is switched to the transfer power supply 52.
Is set at the time when a time of 0.813 sec or more has elapsed from the time T1. However, more specifically,
After the switch 82 is switched to the high-voltage power supply 81 side, a time TD is delayed as shown in FIG. 3 until the potential of the transfer roller 51 reaches a predetermined value. For this reason, preferably
In consideration of this delay TD, the time T2 is advanced by TD from the above. That is, at timing T2, TD is set to, for example,
Assuming that it is 05 sec, it is preferably 0.638 from the time T1.
Set when the time equal to or less than sec has elapsed.
【００２４】このように、感光ドラム１の回転停止時に
おける現像ニップトナーが感光ドラム１の回転開始時に
転写ニップ部を通過する期間には、高圧電源８１が発生
する電圧、すなわちトナーの帯電電圧と同極性の電圧が
転写ローラ５１に供給されている。かくして、感光ドラ
ム１に付着している現像ニップトナーは、電気的に反発
して転写ローラ５１には付着しない。従って、転写ロー
ラ５１に付着したトナーにより記録紙背面が汚れてしま
うこともない。As described above, during the period in which the developing nip toner passes through the transfer nip portion when the rotation of the photosensitive drum 1 is stopped when the rotation of the photosensitive drum 1 is started, the voltage generated by the high voltage power supply 81, that is, the charging voltage of the toner is the same. Polar voltage is supplied to the transfer roller 51. Thus, the developing nip toner adhered to the photosensitive drum 1 repels electrically and does not adhere to the transfer roller 51. Therefore, the back surface of the recording paper is not stained by the toner attached to the transfer roller 51.
【００２５】以上のように本実施例によれば、感光ドラ
ム１上の電位が不定である部分が現像位置Ｂを通過する
期間には現像スリーブ４１の回転は停止状態とすること
により、感光ドラム１のうちの電位が不定である部分へ
のトナーの供給を停止して、当該部分へのトナー付着を
防止でき、トナーの浪費が大幅に低減される。また感光
ドラム１の回転が停止している状態において現像ニップ
部に位置している現像ニップトナーが微少ながら感光ド
ラム１に付着してしまうが、転写ローラ５１にトナーの
帯電極性と同極性の電圧を印加していることにより現像
ニップトナーを転写ローラ５１から反発させているの
で、転写ローラ５１の汚れ、ひいては記録紙の背面の汚
れも確実に防止される。As described above, according to the present embodiment, the rotation of the developing sleeve 41 is stopped during the period when the portion on the photosensitive drum 1 where the potential is unfixed passes the developing position B, so that the photosensitive drum is stopped. By stopping the supply of toner to the portion of 1 where the potential is undefined, it is possible to prevent toner from adhering to the portion, and waste of toner is greatly reduced. Further, while the rotation of the photosensitive drum 1 is stopped, the developing nip toner located in the developing nip portion adheres to the photosensitive drum 1 though it is very small, but the transfer roller 51 is supplied with a voltage having the same polarity as the charged polarity of the toner. Since the developing nip toner is repelled from the transfer roller 51 by the application, the stain on the transfer roller 51 and, consequently, the stain on the back surface of the recording paper are reliably prevented.
【００２６】なお本発明は上記実施例に限定されるもの
ではない。例えば上記実施例では、期間ＴＣの前には転
写ローラ５１への電圧供給をＯＦＦとしておき、また期
間ＴＣの後には転写ローラ５１に転写電源５２が発生す
る電圧を供給しているが、期間ＴＣ以外における転写ロ
ーラ５１への電圧供給は上記実施例と同様でなくても良
い。例えば図４に示すように、期間ＴＣの後に転写ロー
ラ５１への電圧供給を一旦ＯＦＦとし、こののちに転写
ローラ５１に転写電源５２が発生する電圧を供給した
り、また図５に示すように、期間ＴＣの前において転写
ローラ５１に転写電源５２が発生する電圧を供給してお
くなどの変形が可能である。このほか、本発明の要旨を
逸脱しない範囲で種々の変形実施が可能である。The present invention is not limited to the above embodiment. For example, in the above embodiment, the voltage supply to the transfer roller 51 is turned off before the period TC, and the voltage generated by the transfer power supply 52 is supplied to the transfer roller 51 after the period TC. The voltage supply to the transfer roller 51 other than the above may not be the same as that in the above-described embodiment. For example, as shown in FIG. 4, the voltage supply to the transfer roller 51 is temporarily turned off after the period TC, and then the voltage generated by the transfer power supply 52 is supplied to the transfer roller 51, or as shown in FIG. For example, before the period TC, the voltage generated by the transfer power supply 52 may be supplied to the transfer roller 51. In addition, various modifications can be made without departing from the spirit of the present invention.
【００２７】[0027]
【発明の効果】本発明によれば、例えば感光ドラムなど
の感光体の回転開始時に、帯電手段による前記感光体の
帯電が開始された時点に前記帯電手段の帯電位置に位置
していた前記感光体上の所定点が現像手段の現像位置に
至るのに要する時間が経過するまでは例えばスリーブ駆
動系などの担持体回転手段による例えば現像スリーブな
どの現像剤担持体の回転駆動を停止させておき、このの
ちに前記担持体回転手段による前記現像剤担持体の回転
駆動を行わせる例えば制御部などの現像制御手段と、前
記現像剤の帯電極性と同極性の電圧を発生する例えば高
圧電源などの第２電源手段と、前記現像剤の帯電極性と
逆極性の電圧を発生する例えば転写電源などの第１電源
手段が発生する電圧および前記第２電源手段が発生する
電圧のいずれかを前記電圧印加手段に与える例えばスイ
ッチなどの切換手段と、少なくとも前記感光体の回転が
開始された時点に前記現像位置に位置していた前記感光
体上の所定点が前記転写手段の転写位置を通過する際に
は前記電圧印加手段に前記第２電源手段が発生する電圧
を前記電圧印加手段に与えるよう前記切換手段を制御す
る例えば制御部などの転写制御手段とを具備したので、
感光体への無駄な現像剤付着を極力抑え、これにより経
済的かつ高画質に記録を行うことができる電子写真装置
となる。According to the present invention, for example, when the photosensitive member such as a photosensitive drum starts rotating, the photosensitive member positioned at the charging position of the charging unit at the time when the charging of the photosensitive member by the charging unit is started. Until the time required for the predetermined point on the body to reach the developing position of the developing means elapses, the rotation driving of the developer carrier such as the developing sleeve by the carrier rotating means such as the sleeve driving system is stopped. A developing control unit such as a control unit that causes the developer rotating unit to rotate the developer carrier by the carrier rotating unit; and a high-voltage power supply that generates a voltage having the same polarity as the charging polarity of the developer. A second power supply, and a voltage generated by the first power supply, such as a transfer power supply, for generating a voltage having a polarity opposite to the polarity of the developer, or a voltage generated by the second power supply. A switching unit, such as a switch, for applying a voltage to the voltage applying unit, and a predetermined point on the photoconductor, which is located at the developing position at least when the rotation of the photoconductor starts, passes through the transfer position of the transfer unit. When performing the transfer, a transfer control unit such as a control unit that controls the switching unit to apply the voltage generated by the second power supply unit to the voltage application unit to the voltage application unit is provided.
An electrophotographic apparatus capable of recording economically and with high image quality by minimizing wasteful developer adhesion to the photoreceptor is provided.
【図１】 本発明の一実施例に係る電子写真装置の要部
構成を模式的に示す図。FIG. 1 is a diagram schematically showing a main configuration of an electrophotographic apparatus according to an embodiment of the present invention.
【図２】 図１中の各部の動作タイミングを示すタイミ
ング図。FIG. 2 is a timing chart showing the operation timing of each unit in FIG. 1;
【図３】 図１中の転写ローラ５１の電位変化の状態を
示す図。FIG. 3 is a diagram showing a state of a potential change of a transfer roller 51 in FIG.
【図４】 図１中の転写ローラ５１への電圧供給のタイ
ミングの変形例を示す図。FIG. 4 is a diagram showing a modified example of the timing of voltage supply to the transfer roller 51 in FIG.
【図５】 図１中の転写ローラ５１への電圧供給のタイ
ミングの変形例を示す図。FIG. 5 is a diagram showing a modification of the timing of supplying a voltage to the transfer roller 51 in FIG.
【図６】 従来技術を説明する図。FIG. 6 is a diagram illustrating a conventional technique.
１…感光ドラム（感光体）、２…帯電装置（帯電手
段）、３…露光装置（露光手段）、６…クリーニング装
置、７…現像装置（現像手段）、４１…現像スリーブ
（現像剤担持体）、４２…現像バイアス電源、７１…ス
リーブ駆動系（担持体回転手段）、７２…スイッチ、８
…転写装置（転写手段）、５１…転写ローラ（電圧印加
手段）、５２…転写電源（第１電源手段）、８１…高圧
電源（第２電源手段）、８２…スイッチ（切換手段）、
９…感光ドラム駆動系（感光体回転手段）、１０…制御
部（転写制御手段）。1. Photosensitive drum (photoreceptor) 2. Charging device (charging hand)
Step) , 3 ... Exposure device (exposure means) , 6 ... Cleaning device, 7 ... Developing device (developing means) , 41 ... Developing sleeve
(Developer carrier) , 42: developing bias power supply, 71: sleeve drive system (carrier rotating means) , 72: switch, 8
... Transfer device (transfer means) , 51 ... Transfer roller (voltage application
Means , 52 ... transfer power supply (first power supply means) , 81 ... high voltage power supply (second power supply means) , 82 ... switch (switching means) ,
9: photosensitive drum drive system (photoconductor rotating means) ; 10: control unit (transfer control means) .
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G03G 15/08 G03G 15/16 103 G03G 21/14 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 7 , DB name) G03G 15/08 G03G 15/16 103 G03G 21/14
Claims (1)
転手段によって回転駆動される無端状の感光体の周面に
沿って、少なくとも帯電手段、露光手段、現像手段およ
び転写手段を配してなり、これらにより電子写真プロセ
スの各処理を行って画像の記録を行うものであり、 前記現像手段は、担持体回転手段によって回転駆動され
る無端状の現像剤担持体によって担持した、所定の極性
に帯電した現像剤を前記感光体に接触させて現像を行う
ものであり、 また前記転写手段は、前記現像剤の帯電極性とは逆極性
の電圧を発生する第１電源手段と、この第１電源手段に
より発生された前記電圧を前記感光体に重ねられた記録
紙の背面に与える電圧印加手段とを具備したものである
電子写真装置において、 前記感光体の回転開始時に、前記帯電手段による前記感
光体の帯電が開始された時点に前記帯電手段の帯電位置
に位置していた前記感光体上の所定点が前記現像手段の
現像位置に至るのに要する時間が経過するまでは前記担
持体回転手段による前記現像剤担持体の回転駆動を停止
させておき、こののちに前記担持体回転手段による前記
現像剤担持体の回転駆動を行わせる現像制御手段と、 前記現像剤の帯電極性と同極性の電圧を発生する第２電
源手段と、 前記第１電源手段が発生する電圧および前記第２電源手
段が発生する電圧のいずれかを前記電圧印加手段に与え
る切換手段と、 少なくとも前記感光体の回転が開始された時点に前記現
像位置に位置していた前記感光体上の所定点が前記転写
手段の転写位置を通過する際には前記電圧印加手段に前
記第２電源手段が発生する電圧を前記電圧印加手段に与
えるよう前記切換手段を制御する転写制御手段とを具備
したことを特徴とする電子写真装置。1. An image forming apparatus comprising at least a charging unit, an exposing unit, a developing unit, and a transferring unit arranged along a peripheral surface of an endless photoreceptor constituted by a photosensitive conductive member and rotated by a photoreceptor rotating unit. The recording means performs each processing of the electrophotographic process to record an image, and the developing means has a predetermined polarity carried by an endless developer carrier which is rotationally driven by the carrier rotating means. A developing unit that performs development by bringing a charged developer into contact with the photoconductor; and a transfer unit that generates a voltage having a polarity opposite to a polarity of the charged developer; Means for applying the voltage generated by the means to the back surface of the recording paper superimposed on the photosensitive member. Until the time required for a predetermined point on the photoconductor, which was located at the charging position of the charging means at the time when the charging of the photoconductor by the step was started, to reach the developing position of the developing means has elapsed, Development control means for stopping the rotation of the developer carrying member by the carrier rotating means, and thereafter performing the rotation of the developer carrying member by the carrier rotating means; and charging polarity of the developer. A second power supply unit for generating a voltage having the same polarity as the first power supply unit; a switching unit for applying one of a voltage generated by the first power supply unit and a voltage generated by the second power supply unit to the voltage application unit; When a predetermined point on the photoconductor, which is located at the developing position when the rotation of the body is started, passes through the transfer position of the transfer unit, the second power supply unit is generated in the voltage application unit. Voltage Electrophotographic apparatus being characterized in that includes a transfer control means for controlling said switching means to provide said voltage applying means.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4234611A JP3012742B2 (en) | 1992-09-02 | 1992-09-02 | Electrophotographic equipment |
| CA002105255A CA2105255C (en) | 1992-08-31 | 1993-08-31 | Electrophotographic apparatus that prevents toner from attaching to a contact member of a transfer device |
| US08/599,101 US5692232A (en) | 1992-08-31 | 1996-02-09 | Electrophotographic apparatus that prevents toner from attaching to a contact member of a transfer device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4234611A JP3012742B2 (en) | 1992-09-02 | 1992-09-02 | Electrophotographic equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0683176A JPH0683176A (en) | 1994-03-25 |
| JP3012742B2 true JP3012742B2 (en) | 2000-02-28 |
Family
ID=16973759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4234611A Expired - Lifetime JP3012742B2 (en) | 1992-08-31 | 1992-09-02 | Electrophotographic equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3012742B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009198841A (en) * | 2008-02-22 | 2009-09-03 | Ricoh Co Ltd | Image forming device |
| JP6071497B2 (en) | 2012-12-04 | 2017-02-01 | キヤノン株式会社 | Image forming apparatus |
-
1992
- 1992-09-02 JP JP4234611A patent/JP3012742B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0683176A (en) | 1994-03-25 |
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