JPH07181815A - Electrophotographic method and electrophotographic apparatus - Google Patents
Electrophotographic method and electrophotographic apparatusInfo
- Publication number
- JPH07181815A JPH07181815A JP5328231A JP32823193A JPH07181815A JP H07181815 A JPH07181815 A JP H07181815A JP 5328231 A JP5328231 A JP 5328231A JP 32823193 A JP32823193 A JP 32823193A JP H07181815 A JPH07181815 A JP H07181815A
- Authority
- JP
- Japan
- Prior art keywords
- image receiving
- transfer
- receiving paper
- image
- paper
- 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.)
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- Control Or Security For Electrophotography (AREA)
- Electrostatic Charge, Transfer And Separation In Electrography (AREA)
Abstract
(57)【要約】
【目的】 転写ローラ等による接触式の転写方法を用い
る場合、転写ローラによる圧力ため画像に中抜け現象が
生じる。これを、従来のコロナ転写並にすると同時に、
低オゾン化を達成する。
【構成】 接触圧を３００ｇ／ｃｍ2以下にして、転写
に先立ち予め帯電して転写部に導き転写を行う。受像紙
の帯電は、接地した導電性の金属板と半導電性のフィル
ム間に挟み込み低電圧印加による微小放電を利用する。
この帯電方法では、受像紙の種類や厚みの影響を受ける
ので、受像紙の種類を予め検知して、この検知に従い転
写電圧を可変させることによって良好な画像が得られ
る。
(57) [Summary] [Purpose] When a contact type transfer method using a transfer roller or the like is used, a hollow phenomenon occurs in the image due to the pressure of the transfer roller. While making this the same as the conventional corona transfer,
Achieve low ozone. [Structure] A contact pressure is set to 300 g / cm 2 or less, and the toner is charged in advance and transferred to a transfer portion before transfer to perform transfer. The image receiving paper is charged by utilizing a minute discharge by sandwiching it between a grounded conductive metal plate and a semiconductive film and applying a low voltage.
Since this charging method is affected by the type and thickness of the image receiving paper, a good image can be obtained by detecting the type of the image receiving paper in advance and varying the transfer voltage according to this detection.
Description
【０００１】[0001]
【産業上の利用分野】本発明は複写機、ファクシミリ、
プリンターに係り、特に電子写真方法及び電子写真装置
に関するものである。BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a facsimile,
The present invention relates to a printer, and more particularly to an electrophotographic method and an electrophotographic apparatus.
【０００２】[0002]
【従来の技術】近年、画像形成装置はオフィスユースの
目的からパーソナルユースへと移行しつつあり小型化、
メンテフリー等を実現する技術が求められている。パー
ソナルユースを目的とする小型のプリンターは、配置さ
れる場所が机上の隅であったり、一般の家庭で使用され
る場合が想定され、メンテンンス性やオゾン排気が少な
い等の条件が満たされることが普及のポイントとなる。2. Description of the Related Art In recent years, image forming apparatuses have been shifting from the purpose of office use to personal use, and have been downsized.
There is a demand for a technology that realizes maintenance-free operation. Small printers intended for personal use are expected to be placed in a corner of a desk or used in a general household, and may meet conditions such as maintenance and low ozone emissions. It becomes a point of popularization.
【０００３】電子写真方式の複写機、プリンターの印字
プロセスを説明する。先ず、画像形成のために感光体を
帯電する。帯電方法としては、従来から多く用いられて
いるコロナ放電器を使用するもの、また、近年では発生
オゾンの低減を狙って導電性ローラを感光体に直接押圧
した接触型の帯電方法等によって感光体表面を均一に帯
電する。感光体を帯電後、複写機であれば、複写原稿に
光を照射し反射光をレンズ系を通して感光体に照射す
る。或いは、プリンターであれば露光光源としての発光
ダイオードやレーザーダイオードに画像信号を送り光の
ＯＮ−ＯＦＦによって感光体に潜像を形成する。感光体
に潜像（表面電位の高低）が形成されると感光体は予め
帯電された着色粉体であるトナー（直径が５μｍ〜１５
μｍ位）によって顕像化される。トナーは感光体の表面
電位の高低に従って感光体表面に付着し複写用紙に電気
的に転写される。即ち、トナーは予め正または負に帯電
しており複写用紙の背面からトナー極性と反対の極性の
電荷を付与して電気的に吸引する。これまで、この電荷
付与方法としては帯電方法と同じくコロナ放電器が広く
用いられてきたが、オゾン発生の低減のため近年では導
電性ローラを用いた転写装置が実用化されている。A printing process of an electrophotographic copying machine or printer will be described. First, the photoreceptor is charged to form an image. As a charging method, a corona discharger which has been widely used in the past is used, and in recent years, a photoreceptor is applied by a contact-type charging method in which a conductive roller is directly pressed against the photoreceptor in order to reduce ozone generated. Charge the surface uniformly. After the photoconductor is charged, in the case of a copying machine, the copy original is irradiated with light and the reflected light is irradiated onto the photoconductor through a lens system. Alternatively, in the case of a printer, an image signal is sent to a light emitting diode or a laser diode as an exposure light source to form a latent image on the photoconductor by turning the light ON-OFF. When a latent image (high or low surface potential) is formed on the photosensitive member, the photosensitive member is pre-charged with colored toner (5 μm to 15 μm in diameter).
It is visualized by (μm position). The toner adheres to the surface of the photoconductor according to the level of the surface potential of the photoconductor, and is electrically transferred to the copy sheet. That is, the toner is charged positively or negatively in advance, and a charge having a polarity opposite to the polarity of the toner is applied from the back surface of the copy sheet and is electrically attracted. Up to now, a corona discharger has been widely used as the charge applying method as in the charging method, but in recent years, a transfer device using a conductive roller has been put into practical use in order to reduce ozone generation.
【０００４】図４は特開平１−１７７０６３号公報や特
開平２−２２６２８２号公報に開示されたトナー像転写
装置の構成を示す概略図である。図４において、２０は
発泡性または固体状態のゴムなどからなり、体積抵抗値
１０8〜１０13Ωｃｍに調整された転写ローラ、２１は
転写ローラに電圧印加のための電源、２２は感光体、２
３は受像紙（複写用紙）、２４は受像紙を転写ローラ２
０と感光体２２の接触部に導くための導電性のガイド、
２５は抵抗体である。以上のように構成された転写装置
の動作を説明する。FIG. 4 is a schematic diagram showing the structure of the toner image transfer device disclosed in Japanese Patent Application Laid-Open No. 1-177063 and Japanese Patent Application Laid-Open No. 2-226282. In FIG. 4, 20 is a transfer roller made of foamed or solid rubber and adjusted to a volume resistance value of 10 8 to 10 13 Ωcm, 21 is a power source for applying voltage to the transfer roller, 22 is a photoconductor, Two
3 is an image receiving paper (copying paper), 24 is an image receiving paper transfer roller 2
0, a conductive guide for guiding to the contact portion of the photosensitive member 22,
Reference numeral 25 is a resistor. The operation of the transfer device configured as described above will be described.
【０００５】感光体２２の表面には上述したトナーによ
る像が形成されている。今、感光体２２の極性を負、ト
ナーの極性が正の正規現像を想定する。転写ローラ２０
は感光体２２に所定の押圧力で接している。受像紙２３
は感光体２２と転写ローラ２０の接触点（ニップ）に供
給され、転写ローラ２０によって感光体２２に押し当て
られトナーと接触する。転写ローラ２０にはトナーの極
性と反対の負電圧が電源装置２１から印加されているの
でトナーは受像紙２３転写される。転写ローラ２０が受
像紙２３に接触しているので電源２１から印加する電圧
は１．０ｋＶ〜５．０ｋＶである。導電性のガイド２４
は、転写ニップに到達する以前に、受像紙に電界が作用
しトナーが飛翔し、飛び散りの多い画像になることを避
けるために設けられている。また、ガイド２４を抵抗体
２５を介して接地し、不用意な電流の漏洩を防止し転写
性能を確保している。さらに、特開平１−１７７０６３
号公報には、画像中の一部が転写されない、いわゆる”
中抜け”を回避するため、転写ローラ２０の硬度及び圧
接力を規定している。また、受像紙２３が何らかの異常
によって詰まり、転写部に搬送されいと転写ローラ２０
がトナーによって汚れ、受像紙２３の裏汚れの原因とな
る。この場合は、転写ローラ２０に印加する電圧の極性
をトナーと同極性にして、静電的に感光体２２に転写ロ
ーラ２０上のトナーを戻す処置がとられる。トナー像を
転写された受像紙２３は感光体２０と転写ローラ２２の
接触点を過ぎ定着部（図示せず）に搬送される。An image is formed on the surface of the photoconductor 22 by the toner described above. Now, it is assumed that the photoconductor 22 has a negative polarity and the toner has a positive polarity. Transfer roller 20
Is in contact with the photoconductor 22 with a predetermined pressing force. Image receiving paper 23
Is supplied to the contact point (nip) between the photoconductor 22 and the transfer roller 20, and is pressed against the photoconductor 22 by the transfer roller 20 to come into contact with the toner. Since a negative voltage opposite to the polarity of the toner is applied to the transfer roller 20 from the power supply device 21, the toner is transferred to the image receiving paper 23. Since the transfer roller 20 is in contact with the image receiving paper 23, the voltage applied from the power source 21 is 1.0 kV to 5.0 kV. Conductive guide 24
Is provided to prevent the toner from flying due to an electric field acting on the image receiving paper before reaching the transfer nip, resulting in an image with a lot of scattering. Further, the guide 24 is grounded via the resistor 25 to prevent unintentional leakage of current and ensure transfer performance. Furthermore, Japanese Patent Laid-Open No. 1-177063
In the publication, a so-called "part of the image is not transferred"
In order to avoid "middle-out", the hardness and the pressure contact force of the transfer roller 20 are regulated. Further, if the image receiving paper 23 is jammed due to some abnormality and is not conveyed to the transfer portion, the transfer roller 20.
Stains the toner with the toner, and causes the back stain of the image receiving paper 23. In this case, the polarity of the voltage applied to the transfer roller 20 is set to be the same as that of the toner, and the toner on the transfer roller 20 is electrostatically returned to the photoconductor 22. The image receiving paper 23 to which the toner image is transferred passes through the contact point between the photoconductor 20 and the transfer roller 22 and is conveyed to a fixing unit (not shown).
【０００６】[0006]
【発明が解決しようとする課題】上述した転写方法は以
下に示す課題が生じる。The above-mentioned transfer method has the following problems.
【０００７】転写ローラ方式は、これまでのコロナ転写
方式と異なり、オゾン発生が無く、また、装置の小型化
にも適している。しかしながら、コロナ方式に比較して
受像紙からトナーにかかる力は大きいためトナーが凝集
したり、感光体表面に押しつけられたりして画像の中央
部が転写されない”中抜け”現象が避けられない。前述
したように、転写ローラ硬度をできる限り低くし、ま
た、圧接力も小さくして中抜けの発生を極力抑えるが、
完全ではなく、厚紙や葉書用紙に複写する場合は現象が
顕著になる。また、特開平１−１７７０６３号公報にも
記載があるように転写ローラの導電性を向上させるには
導電性のフィラーをゴム材に混ぜなければならないが、
一方、フィラーを混入させると転写ローラの硬度が高く
なり作製が難しくなる。従って、転写ローラ間の品質の
バラツキや、一本の中でも抵抗バラツキが大きくなる等
の問題点がある。Unlike the conventional corona transfer method, the transfer roller method does not generate ozone and is suitable for downsizing of the apparatus. However, since the force exerted on the toner from the image receiving paper is larger than that in the corona system, the "middle void" phenomenon in which the central portion of the image is not transferred due to the toner agglomerating or being pressed against the surface of the photoconductor is inevitable. As described above, the hardness of the transfer roller is made as low as possible, and the pressure contact force is also made small to suppress the occurrence of hollows as much as possible.
The phenomenon is remarkable when copying on a thick paper or a postcard paper, which is not perfect. Further, as described in JP-A No. 1-177063, in order to improve the conductivity of the transfer roller, a conductive filler must be mixed with the rubber material.
On the other hand, if a filler is mixed, the hardness of the transfer roller becomes high, which makes the manufacturing difficult. Therefore, there is a problem that the quality of the transfer rollers varies, and the resistance varies among the transfer rollers.
【０００８】また、、受像紙が環境によって抵抗が変化
したり、或いは、厚みによって転写に必要な電圧は変化
する。特に、オーバーヘッドプロジェクター（ＯＨＰ）
用の受像紙は、普通紙に比べ誘電率が小さいため、普通
紙と同等の電圧では転写が十分に行われない。このた
め、転写に必要な電圧に調整しなければならないが、通
常の転写装置では、感光体に直接影響がでて、画像上の
カブリなどの異常となり良好な性能が得られないという
問題点がある。Further, the resistance of the image receiving paper changes depending on the environment, or the voltage required for transfer changes depending on the thickness. Especially, overhead projector (OHP)
Since the image receiving paper for use has a smaller dielectric constant than plain paper, transfer cannot be sufficiently performed at a voltage equivalent to that of plain paper. For this reason, it is necessary to adjust the voltage required for transfer, but in a normal transfer device, there is a problem in that the photoconductor is directly affected and abnormalities such as fog on the image occur and good performance cannot be obtained. is there.
【０００９】[0009]
【課題を解決するための手段】上記問題点を解決するた
めに本発明は下記の構成を特徴とする電子写真方法及び
電子写真装置である。In order to solve the above problems, the present invention is an electrophotographic method and an electrophotographic apparatus characterized by the following constitutions.
【００１０】本発明は、静電潜像担持体上に現像像を形
成する現像手段と、受像紙を予め帯電した後、前記静電
潜像担持体との間に挟持し、前記現像像を前記受像紙に
転写する導電性電極とを具備し、前記受像紙の種類を検
知し、予め帯電する帯電量を可変する電子写真方法であ
る。According to the present invention, the developing image is formed on the electrostatic latent image carrier and the image receiving paper is pre-charged and then sandwiched between the electrostatic latent image carrier and the developed image. An electrophotographic method comprising a conductive electrode for transferring onto the image receiving paper, detecting the type of the image receiving paper, and varying the amount of charge to be charged in advance.
【００１１】または、静電潜像担持体上に現像像を形成
する現像手段と、受像紙種類の検知手段と、前記受像紙
を前記静電潜像担持体との間に挟持するための直接また
は抵抗を介して接地した導電性電極と、前記受像紙を前
記導電性電極に導くための直接または抵抗を介して接地
した導電性のガイドと、前記受像紙を前記ガイドに押し
つけ帯電させるための半導電性電極と、該半導電性電極
に電圧印加するための電源手段とを具備し、検知手段の
信号に応じて、前記電源手段の印加電圧を可変すること
を特徴とする電子写真装置である。Alternatively, a developing means for forming a developed image on the electrostatic latent image carrier, a means for detecting the type of the image receiving paper, and a direct means for sandwiching the image receiving paper with the electrostatic latent image carrier. Alternatively, a conductive electrode grounded via a resistance, a conductive guide for guiding the image receiving paper to the conductive electrode directly or via a resistance, and a conductive electrode grounded by pressing the image receiving paper against the guide. An electrophotographic apparatus comprising a semi-conductive electrode and a power supply means for applying a voltage to the semi-conductive electrode, wherein the applied voltage of the power supply means is varied according to a signal from the detection means. is there.
【００１２】[0012]
【作用】画像の中央部の転写不良（中抜け）に関して考
察してみる。中抜けは、転写ローラの圧力によって、ト
ナー同士の凝集、感光体表面への付着が起こり発生す
る。特に、転写ローラの長手方向に対して、直角方向の
ライン画像を書いた場合に発生しやすい。これは、トナ
ーの存在する部分としない部分では圧力差が生じるため
で、受像紙が厚紙なるほど顕著となる。中抜けを低減さ
せるためには、トナーへの圧力集中を避ければよいの
で、 １）転写ローラの硬度を下げる ２）感光体上のトナーの厚みを下げる ３）トナーの凝集力を下げる ４）感光体表面の離型性を向上させる ５）感光体と受像紙の速度差を設ける 等の対策が考えられる。しかしながら、１）に示した転
写ローラ硬度を低下させる方法でも、前述したように葉
書等の厚紙には効果が少ない。また、４）感光体表面は
クリーニングなどによって常に摺擦されており、経時変
化は避けられない。 これらの点を改良する方法を次の
ように考えた。[Function] Let us consider the transfer failure (blank area) at the center of the image. Due to the pressure of the transfer roller, hollow defects occur due to aggregation of toner particles and adhesion to the surface of the photoconductor. In particular, it tends to occur when a line image is written in a direction perpendicular to the longitudinal direction of the transfer roller. This is because a pressure difference occurs between the portion where toner is present and the portion where toner is not present, and becomes more noticeable as the image receiving paper becomes thicker. In order to reduce hollow defects, it is sufficient to avoid pressure concentration on the toner, so 1) reduce the hardness of the transfer roller 2) reduce the thickness of the toner on the photoconductor 3) reduce the cohesive force of the toner 4) exposure Improving the releasability of the body surface 5) Measures such as providing a speed difference between the photoconductor and the image receiving paper can be considered. However, even the method of reducing the hardness of the transfer roller described in 1) has little effect on thick paper such as postcards as described above. In addition, 4) the surface of the photoconductor is constantly rubbed by cleaning or the like, so that the change over time cannot be avoided. The method of improving these points was considered as follows.
【００１３】転写時の圧力は極力低く、コロナ転写時程
度がよい。しかし、転写圧力を低下させると、受像紙へ
かかる電界が不安定となり転写ムラとなる。特に、転写
ローラの場合、印加電圧が低圧であるため発生し易い。
そこで、転写に必要な電荷を予め受像紙に付与し、転写
ローラは、受像紙を感光体に軽く押しつける目的で用い
る。この時転写ローラは、帯電した受像紙の通過による
不用意な帯電を避けるため導電性のものがよく、接地す
る。転写に先立つ受像紙帯電は、方法はどんなものでも
よいが、コロナ放電器等を用いるとオゾン発生の原因と
なる。そこで発明者らは、低オゾンの帯電方法を考案し
た。これは、接地された金属板の上に半導電性のフィル
ムを向かい合わせ軽く接触させ、半導電性のフィルムは
電圧発生電源に接続する。金属板と半導電性フィルムの
接触圧は、両者間を受像紙が通過するときほぼ半導電性
のフィルムの一部が受像紙に接触する程度でよい。電圧
発生電源より約５００〜１０００Ｖの電圧を印加し、金
属板と半導電性のフィルム間に受像紙を通過させると、
受像紙と半導電性のフィルム間で微小な放電が起き受像
紙が帯電する。コロナ放電器等を用いると受像紙が帯電
しすぎて転写位置前に感光体上のトナーが受像紙に飛翔
する、いわゆる”前飛び”が起きやすいが、前述した微
小放電を利用するとこの心配も無い。The pressure at the time of transfer is as low as possible, and the pressure at the time of corona transfer is good. However, when the transfer pressure is lowered, the electric field applied to the image receiving paper becomes unstable, resulting in uneven transfer. In particular, in the case of a transfer roller, it easily occurs because the applied voltage is low.
Therefore, the charge necessary for transfer is applied to the image receiving paper in advance, and the transfer roller is used for the purpose of lightly pressing the image receiving paper against the photoconductor. At this time, the transfer roller is preferably a conductive one and is grounded in order to avoid inadvertent charging due to the passage of the charged image receiving paper. Any method may be used for charging the image receiving paper prior to transfer, but if a corona discharger or the like is used, ozone will be generated. Therefore, the inventors have devised a low ozone charging method. In this method, a semiconductive film is faced to and lightly contacted with a grounded metal plate, and the semiconductive film is connected to a voltage generating power source. The contact pressure between the metal plate and the semiconductive film may be such that a part of the substantially semiconductive film comes into contact with the image receiving paper when the image receiving paper passes between them. When a voltage of about 500 to 1000 V is applied from a voltage generating power source and an image receiving paper is passed between the metal plate and the semiconductive film,
A minute discharge occurs between the image receiving paper and the semiconductive film, and the image receiving paper is charged. When a corona discharger is used, the image receiving paper is charged too much, and the toner on the photoconductor flies to the image receiving paper before the transfer position, so-called "front jump" is likely to occur, but when using the minute discharge described above, this concern also occurs. There is no.
【００１４】しかしながら、上述したように接地または
電圧印加された電極間に受像紙を通過させて帯電する方
法では、受像紙の厚みや、誘電率によって電極間にかか
る電界が変化する。例えば、普通受像紙と葉書用紙、普
通受像紙とＯＨＰ用紙などである。電界が変化すると微
小放電の状態が変化して帯電状況が変化する。特に、受
像紙が厚くなると電界の不足によって帯電低下を起こし
転写不良となる。これを回避するためには、受像紙が給
紙カセットやトレイにセットされた時点て受像紙の幅か
らおおよその厚みを検知して、電極間にかける電圧を変
化させることである。或いは、ＯＨＰなどは透明である
ので、作業者が給紙の時点で手動にてスイッチを切り替
え電圧を変化させることも可能である。何らかの方法で
受像紙の種類を検知し、転写に必要な電荷を与えるべく
電圧を変化させることで適正な転写画像が得られる。However, as described above, in the method of charging the image receiving sheet by passing the image receiving sheet between the electrodes to which the ground or the voltage is applied, the electric field applied between the electrodes changes depending on the thickness of the image receiving sheet and the dielectric constant. For example, ordinary image receiving paper and postcard paper, ordinary image receiving paper and OHP paper, and the like. When the electric field changes, the state of minute discharge changes and the charging state changes. In particular, when the image receiving paper becomes thick, the charge is lowered due to the lack of an electric field, resulting in a transfer failure. To avoid this, when the image receiving paper is set in the paper feed cassette or tray, the approximate thickness is detected from the width of the image receiving paper, and the voltage applied between the electrodes is changed. Alternatively, since the OHP or the like is transparent, it is possible for the operator to manually switch the switch at the time of paper feeding to change the voltage. An appropriate transfer image can be obtained by detecting the type of the image receiving paper by some method and changing the voltage so as to give an electric charge required for transfer.
【００１５】[0015]
【実施例】図１は本発明に従う実施例の画像形成装置の
構成構成図である。1 is a block diagram showing the arrangement of an image forming apparatus according to an embodiment of the present invention.
【００１６】図１において、１は静電潜像保持体として
の感光体で、導電性の基材上に電荷発生層としてフタロ
シアニン系の顔料を樹脂に分散したものを用い、電荷発
生層上に電荷輸送層としてヒドラゾンを樹脂に混合して
感光層の膜厚を２０μｍとした有機感光体を用いた。感
光体１の外径は３０ｍｍ、導電性の基材はアルミニウム
で厚み１ｍｍの負帯電有機感光体を用いた。２は感光体
１を帯電するコロナ放電装置、３は感光体に像露光に行
うための露光装置、４は露光後の潜像を顕像化するため
の現像装置で、感光体１に磁性の現像剤であるトナーを
付着させるために感光体１に内包した固定の磁場発生用
磁石４ａと、電圧を印加して画像部以外の余分なトナー
を回収するための導電性部材からなる現像電極４ｂ、現
像電極４ｂに電圧印加と保持電界印加が可能な電源装置
４ｃからなる。現像電極４ｂには交流（ＡＣ）と直流
（ＤＣ）が単独または重畳し、電源装置４ｃによって印
加される。５は感光体１に接触するように設定された転
写ローラである。転写ローラ５は導電性の部材からなる
軸の周囲に導電性ゴムを設けた弾性のローラである。感
光体１への押圧力は、画像の中抜け発生率から設定す
る。図２は、アスカーＣで６０度と高硬度の転写ローラ
５とアスカーＣで３０度と低硬度の転写ローラ５を用
い、葉書用紙９０ｇ／ｍ2紙を用いて押圧力と画像の中
抜け発生率との関係を示したものである。ここで、中抜
け発生率とは、転写ローラ５の長手方向と直角方向のラ
イン幅約０．２ｍｍの線画の中抜け発生量を単位面積当
たりで比較して割り出したものである。図２中一点鎖線
は、普通紙６０ｇ／ｍ2紙の中抜け発生率を示すライン
である。葉書用紙を用いた場合の中抜け発生率を普通紙
並に抑えるためには高硬度ローラでは約１８５ｇ／ｃｍ
2、低硬度ローラでは約３００ｇ／ｃｍ2となる。従っ
て、現在製造可能なローラを用いて、画像中抜けの無い
転写を行うには押圧力は３００ｇ／ｃｍ2以下が適切で
ある。感光体１と転写ローラ５との接触ニップは約２ｍ
ｍであった。転写ローラ５の感光体１への押圧力は押圧
するのバネの縮み量から割り出した。本実施例では、転
写ローラ５は直径６ｍｍのシャフトの周囲に発泡性の導
電性ウレタンエラストマーを抵抗値１０7Ω（軸と表面
に電極を設け、両者に５００Ｖ印加する）にしたものを
用いた。転写ローラ５全体の外径は１８．７ｍｍで、硬
度はアスカーＣで６５度であった。押圧力は約１８５ｇ
／ｃｍ2で用いた。６は受像紙を予め帯電するための転
写帯電部材で、受像紙表面に接触して帯電を行う半導電
性電極６ａと、受像紙に半導電性電極６ａを押しつける
ための押圧スポンジ６ｂと、半導電性電極６ａに電圧印
加するための電源６ｃからなる。半導電性電極６ａの構
造を図３に示す。基材は樹脂フィルム１８で、膜厚は約
７０〜１００μｍである。本実施例ではポリエチレンテ
レフタレート（ＰＥＴ）を用いた。表面の導電層１９は
樹脂中に導電性フィラーを分散させスプレーや浸漬法に
よって塗布したもので、抵抗は約１０6〜１０7Ω／□で
ある。用いる樹脂はポリカーボネート樹脂や、ウレタン
樹脂、シリコーン樹脂、フッ素樹脂など高絶縁性であれ
ば何でもよい。本実施例ではポリカーボネート樹脂を用
いた。塗布膜厚は約２０μｍである。７は受像紙を転写
ローラ５に導入、及び、半導電性電極６ａとともに受像
紙を挟み込み帯電させるため導電性部材からなる突入ガ
イドで、直接接地してもよいし、１００ＭΩ以上の抵抗
を介して接地してもよい。半導電性電極６ａは、押圧ス
ポンジ６ｂによってガイド７または受像紙に押しつけら
れるが、その線圧は１ｋｇ／ｍｍ以下で、本実施例で
は、約１００ｇ／ｍｍで用いた。６ｃの電源は、半導電
性電極６ａに接続し、定電圧または定電流方法によって
印加する。In FIG. 1, reference numeral 1 denotes a photosensitive member as an electrostatic latent image holding member, which uses a conductive base material in which a phthalocyanine-based pigment is dispersed in a resin as a charge generating layer. As the charge transport layer, an organic photoconductor was used in which hydrazone was mixed with resin so that the thickness of the photoconductive layer was 20 μm. The outer diameter of the photoconductor 1 was 30 mm, the conductive base material was aluminum, and a negatively charged organic photoconductor having a thickness of 1 mm was used. Reference numeral 2 is a corona discharge device for charging the photoconductor 1, 3 is an exposure device for performing image exposure on the photoconductor, and 4 is a developing device for visualizing a latent image after exposure. A fixed magnetic field generating magnet 4a included in the photoreceptor 1 for adhering toner as a developer, and a developing electrode 4b made of a conductive member for applying a voltage to collect excess toner other than the image portion. , A power supply device 4c capable of applying a voltage and a holding electric field to the developing electrode 4b. Alternating current (AC) and direct current (DC) are singly or superposed on the developing electrode 4b, and are applied by the power supply device 4c. Reference numeral 5 denotes a transfer roller set so as to come into contact with the photoconductor 1. The transfer roller 5 is an elastic roller in which a conductive rubber is provided around a shaft made of a conductive member. The pressing force on the photoconductor 1 is set based on the occurrence rate of the image dropout. 2, using a transfer roller 5 of 30 degrees and a low hardness transfer roller 5 and the Asker C 60 ° and high hardness in Asker C, missing in the pressing force to the image using the postcard paper 90 g / m 2 paper generated It shows the relationship with the rate. Here, the dropout occurrence rate is calculated by comparing the dropout occurrence amount of a line image having a line width of about 0.2 mm in the direction perpendicular to the longitudinal direction of the transfer roller 5 per unit area. In FIG. 2, the alternate long and short dash line is a line showing the occurrence rate of hollow defects of 60 g / m 2 plain paper. Approximately 185 g / cm with a high hardness roller in order to suppress the occurrence of voids when using postcard paper to the same level as plain paper.
2, the low hardness roller is about 300 g / cm 2. Thus, using current manufacturable roller, the pressing force to effect transfer without omission in the image is appropriate 300 g / cm 2 or less. The contact nip between the photoconductor 1 and the transfer roller 5 is about 2 m.
It was m. The pressing force of the transfer roller 5 on the photosensitive member 1 was calculated from the amount of contraction of the pressing spring. In the present embodiment, the transfer roller 5 used is one in which a foaming conductive urethane elastomer has a resistance value of 10 7 Ω (a shaft and a surface are provided with electrodes and 500 V is applied to both of them) around a shaft having a diameter of 6 mm. . The entire outer diameter of the transfer roller 5 was 18.7 mm and the hardness of Asker C was 65 degrees. Pressing force is about 185g
/ Cm 2 was used. Reference numeral 6 denotes a transfer charging member for precharging the image receiving paper, a semi-conductive electrode 6a for contacting with the surface of the image receiving paper for charging, a pressing sponge 6b for pressing the semi-conductive electrode 6a against the image receiving paper, and a semi-conductive electrode 6b. It comprises a power supply 6c for applying a voltage to the conductive electrode 6a. The structure of the semiconductive electrode 6a is shown in FIG. The base material is the resin film 18, and the film thickness is about 70 to 100 μm. In this example, polyethylene terephthalate (PET) was used. The conductive layer 19 on the surface is obtained by dispersing a conductive filler in a resin and applying it by spraying or dipping, and has a resistance of about 10 6 to 10 7 Ω / □. Any resin may be used as long as it has a high insulating property such as a polycarbonate resin, a urethane resin, a silicone resin, or a fluororesin. In this example, a polycarbonate resin was used. The coating film thickness is about 20 μm. Reference numeral 7 denotes a rush guide formed of a conductive member for introducing the image receiving paper to the transfer roller 5 and sandwiching the image receiving paper together with the semi-conductive electrode 6a for charging, which may be directly grounded or through a resistance of 100 MΩ or more. You may ground it. The semiconductive electrode 6a is pressed against the guide 7 or the image receiving paper by the pressing sponge 6b, and the linear pressure is 1 kg / mm or less, and in this embodiment, it was used at about 100 g / mm. The power source of 6c is connected to the semiconductive electrode 6a and is applied by a constant voltage or constant current method.
【００１７】予め、受像紙の種類を検知して、印加する
電圧、電流を決定してもよい。受像紙の種類を検知する
には、受像紙幅より類推することができる。通常、葉書
はＡ４やＢ５等のプリント用紙と比べＡ４サイズの半分
と幅が狭い。これを利用して葉書と普通受像紙との厚み
比、約２〜３倍の電圧を予め印加する。また、ＯＨＰ用
紙の場合は、普通の受像紙とは異なり透明であるため、
作業者の手動によってスイッチ切り替えを行ってもよ
い。さらに、何らかの方法で受像紙の抵抗を検知し、印
加する電圧を可変させてもよい。本実施例では、定電圧
印加方法を用い、また、トナーは負極性の反転現像方式
を用いたので、印加電圧はプラス約１〜１．５ｋＶであ
った。ＯＨＰ用紙への適正な転写を行うため、転写電圧
を切り換える手動のスイッチを設けた。普通の受像紙に
転写をおこう場合は、転写電圧約０．５ｋＶ、ＯＨＰ用
紙に転写を行う場合は、約１．５ｋＶとした。８は樹脂
部材からなる搬送ガイドである。受像紙が感光体１と転
写ローラ５と分離する近傍に、接地または電圧印加した
針や導電ブラシ等の除電手段を配置してもよい。９は定
着装置で、導電性の管材上にフッ素またはシルコーン系
の樹脂中に導電性粉末を分散した導電性塗料を塗布した
ヒートーローラ９ａとシリコーン系のゴムからなる加圧
用バックアップローラ９ｂからなる。ヒートローラ９ａ
の中にはハロゲンランプを配置し加熱できる。また、ヒ
ートローラ９ａの軸受けは導電性のもの用い、定着装置
９の匡体と電気的に導通させ、匡体を１００ＭΩ以上の
抵抗を介して接地する。本実施例では、感光体１と転写
ローラ５との接触ニップと突入ガイド先端との距離は約
５ｍｍ、また、定着装置９のヒートローラ９ａと加圧ロ
ーラ９ｂとの接触ニップと転写部位間の距離は約９０ｍ
ｍである。突入ガイド７と接地間に挿入した抵抗値は２
００ＭΩ、また、定着装置９と接地間に挿入した抵抗も
２００ＭΩであった。１０は受像紙、１１は感光体１表
面に転写後残留するトナーをクリーニングするためのク
リーニング装置、１２はトナーである。トナー１２は平
均粒径が約１２μｍで、磁性絶縁性で負電荷を帯びてい
る。１５は、受像紙１０に印加する電圧を切り換える転
写電圧切り替えスイッチである。The applied voltage and current may be determined in advance by detecting the type of image receiving paper. In order to detect the type of image receiving paper, it is possible to make an analogy from the width of the image receiving paper. Usually, a postcard is half the width of an A4 size sheet, which is narrower than the width of an A4 or B5 print sheet. Utilizing this, a voltage of about 2 to 3 times the thickness ratio between the postcard and the ordinary image receiving paper is applied in advance. Also, in the case of OHP paper, unlike ordinary image receiving paper, it is transparent, so
The switch may be switched manually by the operator. Furthermore, the resistance of the image receiving paper may be detected by some method and the applied voltage may be varied. In this embodiment, the constant voltage application method was used and the negative polarity reversal development method was used for the toner, so the applied voltage was about 1 to 1.5 kV plus. A manual switch for switching the transfer voltage was provided in order to perform proper transfer to the OHP paper. The transfer voltage was set to about 0.5 kV when transferring to ordinary image receiving paper, and about 1.5 kV when transferring to OHP paper. Reference numeral 8 is a conveyance guide made of a resin member. A static eliminator such as a grounded or voltage-applied needle or a conductive brush may be arranged in the vicinity of where the image receiving paper separates the photoreceptor 1 and the transfer roller 5. A fixing device 9 is composed of a heat roller 9a in which a conductive coating material in which conductive powder is dispersed in fluorine or silcon resin is applied on a conductive tube material, and a pressure backup roller 9b made of silicone rubber. Heat roller 9a
A halogen lamp can be placed inside and heated. Further, the bearing of the heat roller 9a is made of a conductive material, and is electrically connected to the casing of the fixing device 9, and the casing is grounded via a resistance of 100 MΩ or more. In this embodiment, the distance between the contact nip between the photoconductor 1 and the transfer roller 5 and the tip of the entry guide is about 5 mm, and the contact nip between the heat roller 9a and the pressure roller 9b of the fixing device 9 and the transfer portion. Distance is about 90m
m. The resistance value inserted between the plunge guide 7 and the ground is 2
The resistance inserted between the fixing device 9 and the ground was also 200 MΩ. Reference numeral 10 is an image receiving paper, 11 is a cleaning device for cleaning the toner remaining on the surface of the photosensitive member 1 after transfer, and 12 is toner. The toner 12 has an average particle size of about 12 μm, is magnetically insulating, and is negatively charged. Reference numeral 15 is a transfer voltage selector switch for switching the voltage applied to the image receiving paper 10.
【００１８】上述した装置を用いて動作を説明する。印
字動作を開始する前に転写電圧切り替えスイッチを動作
させる。もしも、ＯＨＰ用紙に印字したい場合は、転写
電圧切り替えスイッチ１５を高圧側（Ａ）にする。普通
の受像紙１０を用いる場合は転写電圧切り替えスイッチ
１５を（Ｂ）側にする。本実施例では、（Ａ）に接続下
場合は１．５ｋＶ、（Ｂ）に接続した場合は、０．５ｋ
Ｖの転写電圧が発生する。The operation will be described using the apparatus described above. Operate the transfer voltage selector switch before starting the printing operation. If it is desired to print on OHP paper, the transfer voltage selector switch 15 is set to the high voltage side (A). When using the ordinary image receiving paper 10, the transfer voltage changeover switch 15 is set to the (B) side. In this embodiment, 1.5 kV when connected to (A) and 0.5 kV when connected to (B).
A transfer voltage of V is generated.
【００１９】感光体１はコロナ放電装置２を用いて表面
を負帯電する。帯電後、露光装置３で感光体１表面電荷
による潜像を現像装置４によって顕像化する。顕像化
は、感光体１の基材内部に内包した磁石４ａによって感
光体１表面に磁性現像剤としてのトナー１２を付着させ
る。感光体１の表面電位と近似の現像バイアスを回収ロ
ーラ４ｂに電源装置４ｃにより印加する反転現像法を用
いると、露光装置３によって露光された部分の感光体表
面電位は低くなり、この部分に負極性に帯電したトナー
１２が付着し、感光体表面電位の高い非画像部のトナー
１２は回収ローラ１９ｂに回収される。感光体１上の現
像像が転写ローラ５との接触位置にさしかかる前に、画
像部が合うように受像紙１０は給紙トレイ（図示せず）
から半導電性電極６ａとガイド７との間に供給される。
受像紙１０の供給と同時に、電源６ｃから電圧が印加さ
れて、受像紙１０表面はプラス、背面はマイナスに分極
して帯電する。帯電した受像紙１０は、接地された転写
ローラ５位置にさしかかると、受像紙１０の帯電電荷に
誘起され接地部より転写ローラ５にプラス電荷が流れ、
受像紙１０背面の電荷を相殺し、同時に感光体１上のト
ナー像を転写する。転写を終了すると、受像紙１０の背
面電荷と転写ローラ５に流入した電荷との引き合いによ
って受像紙１０は感光体１から分離する。受像紙１０は
搬送ガイド８を経て定着装置９を通り、トナー１２は受
像紙１０上に固着される。転写工程後の感光体１上の転
写せずに残留するトナー１２はクリーニング装置１１に
で廃トナーボックスに回収される。The surface of the photoreceptor 1 is negatively charged by using the corona discharge device 2. After charging, the developing device 4 visualizes the latent image formed by the surface charges of the photoconductor 1 by the exposure device 3. For visualization, the toner 12 as a magnetic developer is attached to the surface of the photoconductor 1 by the magnet 4a contained inside the base material of the photoconductor 1. When the reversal developing method in which a developing bias similar to the surface potential of the photoconductor 1 is applied to the collection roller 4b by the power supply device 4c, the photoconductor surface potential of the portion exposed by the exposure device 3 becomes low, and the negative electrode is applied to this portion. The electrically charged toner 12 adheres to the toner 12, and the toner 12 in the non-image portion having a high photoreceptor surface potential is collected by the collecting roller 19b. Before the developed image on the photoconductor 1 reaches the contact position with the transfer roller 5, the image receiving paper 10 is placed in a paper feed tray (not shown) so that the image portions are aligned.
Is supplied between the semiconductive electrode 6a and the guide 7.
Simultaneously with the supply of the image receiving paper 10, a voltage is applied from the power supply 6c, and the surface of the image receiving paper 10 is polarized positively and the rear surface is negatively charged. When the charged image receiving paper 10 reaches the position of the transfer roller 5 which is grounded, a positive charge is caused to flow from the grounding portion to the transfer roller 5 by being induced by the charge of the image receiving paper 10.
The charges on the back surface of the image receiving paper 10 are offset, and at the same time, the toner image on the photoconductor 1 is transferred. When the transfer is completed, the image receiving paper 10 is separated from the photoconductor 1 by the attraction of the back surface charge of the image receiving paper 10 and the charge flowing into the transfer roller 5. The image receiving paper 10 passes through the conveyance guide 8 and the fixing device 9, and the toner 12 is fixed on the image receiving paper 10. After the transfer process, the toner 12 remaining on the photosensitive member 1 without being transferred is collected by the cleaning device 11 in the waste toner box.
【００２０】[0020]
【発明の効果】以上のように本発明は、静電潜像担持体
上に現像像を形成する現像手段と、受像紙を予め帯電し
た後、前記静電潜像担持体との間に挟持し、前記現像像
を前記受像紙に転写する導電性電極とを具備し、前記受
像紙の種類を検知し、予め帯電する帯電量を可変する電
子写真方法である。As described above, according to the present invention, the developing means for forming a developed image on the electrostatic latent image carrier and the electrostatic latent image carrier after the image receiving paper is pre-charged are sandwiched. The electrophotographic method comprises a conductive electrode for transferring the developed image onto the image receiving paper, detecting the type of the image receiving paper, and varying the amount of charge to be charged in advance.
【００２１】または、静電潜像担持体上に現像像を形成
する現像手段と、受像紙種類の検知手段と、前記受像紙
を前記静電潜像担持体との間に挟持するための直接また
は抵抗を介して接地した導電性電極と、前記受像紙を前
記導電性電極に導くための直接または抵抗を介して接地
した導電性のガイドと、前記受像紙を前記ガイドに押し
つけ帯電させるための半導電性電極と、該半導電性電極
に電圧印加するための電源手段とを具備し、検知手段の
信号に応じて、前記電源手段の印加電圧を可変すること
を特徴とする電子写真装置によって、良好な画像を得る
ことができる。Alternatively, a developing means for forming a developed image on the electrostatic latent image carrier, a means for detecting the type of the image receiving paper, and a direct means for sandwiching the image receiving paper with the electrostatic latent image carrier. Alternatively, a conductive electrode grounded via a resistance, a conductive guide for guiding the image receiving paper to the conductive electrode directly or via a resistance, and a conductive electrode grounded by pressing the image receiving paper against the guide. An electrophotographic apparatus comprising a semiconductive electrode and power supply means for applying a voltage to the semiconductive electrode, wherein the applied voltage of the power supply means is varied according to a signal from the detection means. , A good image can be obtained.
【００２２】前述したように、転写ローラ方式の転写で
は、受像紙にかかる圧力が大きいため、中抜けが発生し
易い。しかしながら、単に接触圧を低下させただけで
は、転写電界が不均一となり転写がムラとなる。そこ
で、接触圧を３００ｇ／ｃｍ2以下にして、転写に先立
ち予め帯電して転写部に導き転写を行う。受像紙の帯電
は、接地した導電性の金属板と半導電性のフィルム間に
挟み込み低電圧印加による微小放電を利用する。このよ
うな帯電方法を用いると、受像紙の種類や厚みによっ
て、受像紙の帯電状況が変化するので、予め受像紙の状
況を検知して転写電圧を可変させることによって良好な
画像が得られる。As described above, in the transfer using the transfer roller system, since the pressure applied to the image receiving paper is large, the hollow portion is likely to occur. However, if the contact pressure is simply reduced, the transfer electric field becomes non-uniform and the transfer becomes uneven. Therefore, the contact pressure is set to 300 g / cm 2 or less, and the particles are precharged prior to the transfer and guided to the transfer portion to perform the transfer. The image receiving paper is charged by utilizing a minute discharge by sandwiching it between a grounded conductive metal plate and a semiconductive film and applying a low voltage. When such a charging method is used, the charged state of the image receiving sheet changes depending on the type and thickness of the image receiving sheet. Therefore, a good image can be obtained by previously detecting the state of the image receiving sheet and varying the transfer voltage.
【図１】本発明の実施例における画像形成装置の構成概
略図FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.
【図２】高硬度転写ローラと低硬度転写ローラを用いた
場合の、転写押圧力と画像中抜け率の関係を示す示す図FIG. 2 is a diagram showing a relationship between a transfer pressing force and an image dropout rate when a high hardness transfer roller and a low hardness transfer roller are used.
【図３】転写帯電部材の内、半導電性電極の構成を示す
図FIG. 3 is a diagram showing a configuration of a semiconductive electrode of a transfer charging member.
【図４】従来の転写ローラ方法を説明するための概略図FIG. 4 is a schematic diagram for explaining a conventional transfer roller method.
１ 感光体 ２ コロナ放電装置 ３ 露光装置 ４ 現像装置 ４ａ 磁場発生用磁石 ４ｂ 現像電極 ４ｃ 電源装置 ５ 転写ローラ ６ａ 半導電性電極 ６ｂ 押圧スポンジ ６ｃ 電源 ７ ガイド ９ 定着装置 ９ａ ヒートローラ ９ｂ 加圧ローラ １５ 転写電圧切り替えスイッチ DESCRIPTION OF SYMBOLS 1 photoconductor 2 corona discharge device 3 exposure device 4 developing device 4a magnetic field generating magnet 4b developing electrode 4c power supply device 5 transfer roller 6a semi-conductive electrode 6b pressing sponge 6c power supply 7 guide 9 fixing device 9a heat roller 9b pressure roller 15 Transfer voltage switch
Claims (2)
手段と、受像紙を予め帯電した後、前記静電潜像担持体
との間に挟持し、前記現像像を前記受像紙に転写する導
電性電極とを具備し、 前記受像紙の種類を検知し、予め帯電する帯電量を可変
する電子写真方法。1. A developing means for forming a developed image on an electrostatic latent image carrier, and an image receiving paper which has been charged in advance and is sandwiched between the electrostatic latent image carrier and the developed image. An electrophotographic method, comprising: a conductive electrode for transferring onto paper, detecting the type of the image receiving paper, and varying a precharge amount.
手段と、受像紙種類の検知手段と、前記受像紙を前記静
電潜像担持体との間に挟持するための直接または抵抗を
介して接地した導電性電極と、前記受像紙を前記導電性
電極に導くための直接または抵抗を介して接地した導電
性のガイドと、前記受像紙を前記ガイドに押しつけ帯電
させるための半導電性電極と、該半導電性電極に電圧印
加するための電源手段とを具備し、 検知手段の信号に応じて、前記電源手段の印加電圧を可
変することを特徴とする電子写真装置。2. A developing means for forming a developed image on an electrostatic latent image carrier, a means for detecting the type of image receiving paper, and a direct means for sandwiching the image receiving paper with the electrostatic latent image carrier. Alternatively, a conductive electrode grounded via a resistance, a conductive guide for guiding the image receiving paper to the conductive electrode directly or via a resistance, and a conductive electrode grounded by pressing the image receiving paper against the guide. An electrophotographic apparatus comprising a semiconductive electrode and a power supply means for applying a voltage to the semiconductive electrode, wherein the applied voltage of the power supply means is varied according to a signal from the detection means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5328231A JPH07181815A (en) | 1993-12-24 | 1993-12-24 | Electrophotographic method and electrophotographic apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5328231A JPH07181815A (en) | 1993-12-24 | 1993-12-24 | Electrophotographic method and electrophotographic apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07181815A true JPH07181815A (en) | 1995-07-21 |
Family
ID=18207912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5328231A Pending JPH07181815A (en) | 1993-12-24 | 1993-12-24 | Electrophotographic method and electrophotographic apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07181815A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6856782B2 (en) | 1997-01-31 | 2005-02-15 | Seiko Epson Corporation | Intermediate transfer unit having a primary and a secondary transfer member |
| US6957032B2 (en) | 1997-01-31 | 2005-10-18 | Seiko Epson Corporation | Intermediate transfer unit having a primary transfer member and a secondary transfer roller |
| US7203447B2 (en) * | 2002-06-24 | 2007-04-10 | Canon Kabushiki Kaisha | Image forming apparatus with first and second openable portions |
| US7539448B2 (en) | 2005-01-28 | 2009-05-26 | Brother Kogyo Kabushiki Kaisha | Image-forming device for suppressing vibration of guide plate and jams of recording sheet |
| US7539447B2 (en) | 2005-01-28 | 2009-05-26 | Brother Kogyo Kabushiki Kaisha | Image-forming device for absorbing vibration of guide plate |
| US7539446B2 (en) | 2005-01-28 | 2009-05-26 | Brother Kogyo Kabushiki Kaisha | Process cartridge and image forming apparatus with flexible guide members |
| US7542709B2 (en) | 2005-01-28 | 2009-06-02 | Brother Kogyo Kabushiki Kaisha | Image-forming device for suppressing recording sheet from flapping when transferring toner images thereon |
| JP2018136383A (en) * | 2017-02-20 | 2018-08-30 | キヤノン株式会社 | Image forming apparatus |
-
1993
- 1993-12-24 JP JP5328231A patent/JPH07181815A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6856782B2 (en) | 1997-01-31 | 2005-02-15 | Seiko Epson Corporation | Intermediate transfer unit having a primary and a secondary transfer member |
| US6957032B2 (en) | 1997-01-31 | 2005-10-18 | Seiko Epson Corporation | Intermediate transfer unit having a primary transfer member and a secondary transfer roller |
| US7187893B2 (en) | 1997-01-31 | 2007-03-06 | Seiko Epson Corporation | Image transfer unit having an intermediate transfer belt to which a toner image is applied |
| US7203447B2 (en) * | 2002-06-24 | 2007-04-10 | Canon Kabushiki Kaisha | Image forming apparatus with first and second openable portions |
| US7539448B2 (en) | 2005-01-28 | 2009-05-26 | Brother Kogyo Kabushiki Kaisha | Image-forming device for suppressing vibration of guide plate and jams of recording sheet |
| US7539447B2 (en) | 2005-01-28 | 2009-05-26 | Brother Kogyo Kabushiki Kaisha | Image-forming device for absorbing vibration of guide plate |
| US7539446B2 (en) | 2005-01-28 | 2009-05-26 | Brother Kogyo Kabushiki Kaisha | Process cartridge and image forming apparatus with flexible guide members |
| US7542709B2 (en) | 2005-01-28 | 2009-06-02 | Brother Kogyo Kabushiki Kaisha | Image-forming device for suppressing recording sheet from flapping when transferring toner images thereon |
| JP2018136383A (en) * | 2017-02-20 | 2018-08-30 | キヤノン株式会社 | Image forming apparatus |
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