JPH04281486A - Transfer device for image forming device - Google Patents

Transfer device for image forming device

Info

Publication number
JPH04281486A
JPH04281486A JP3104957A JP10495791A JPH04281486A JP H04281486 A JPH04281486 A JP H04281486A JP 3104957 A JP3104957 A JP 3104957A JP 10495791 A JP10495791 A JP 10495791A JP H04281486 A JPH04281486 A JP H04281486A
Authority
JP
Japan
Prior art keywords
transfer
paper
bias
voltage
transfer roller
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP3104957A
Other languages
Japanese (ja)
Inventor
Takayasu Yunamochi
貴康 弓納持
Koichi Tanigawa
谷川 耕一
Akihiko Takeuchi
昭彦 竹内
Hideyuki Yano
秀幸 矢野
Hideo Nanataki
秀夫 七瀧
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP3104957A priority Critical patent/JPH04281486A/en
Publication of JPH04281486A publication Critical patent/JPH04281486A/en
Pending legal-status Critical Current

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  • Control Or Security For Electrophotography (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)

Abstract

PURPOSE:To prevent a transfer current from being increased and to execute the excellent transfer even when transfer is executed on a transfer paper which is humidified under a high humid environment and whose resistance value is lowered by obtaining such constitution that an electrode member on which a bias is impressed is provided near a transfer member and the current is made to flow to the electrode member from the transfer member under the state of the high humid environment. CONSTITUTION:A toner image formed and carried on the surface of an electrophotographic photosensitive drum 1 is transferred on the transfer paper which is made to abut on the drum 1 and passed through the drum 1 and a transfer roller 5 on which the bias is impressed. Then, the bias impressed on the roller 5 when the paper is passed and the transfer is executed is controlled to a constant voltage by impressing the bias of the constant current on the roller 5 abutting on the dark potential part of the drum 1 when the paper is not passed and deciding the transfer voltage when the paper is passed and the transfer is executed based on the voltage generated at that time. Besides, an electrode plate 21 on which the bias voltage is impressed is arranged at a position near the roller 5 where the current from the roller 5 is made to flow in when the bias of the constant current is impressed on the roller 5 when the paper is not passed under the high humid environment.

Description

【発明の詳細な説明】[Detailed description of the invention]

【0001】0001

【産業上の利用分野】本発明は電子写真装置・静電記録
装置等の画像形成装置における転写装置に関する。より
詳しくは、電子写真感光体・静電記録誘電体等の画像担
持体面に、該画像担持体面を所定の暗電位に帯電(一次
帯電)する工程を含む作像プロセスにより可転写画像を
形成担持させ、該可転写画像を、該画像担持体と該画像
担持体に当接させてバイアスを印加した転写部材との間
に通紙した転写材へ転写させる画像形成装置の転写装置
に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus. More specifically, a transferable image is formed and carried on the surface of an image carrier such as an electrophotographic photoreceptor or an electrostatic recording dielectric material by an image forming process that includes a step of charging the image carrier surface to a predetermined dark potential (primary charging). The present invention relates to a transfer device of an image forming apparatus that transfers the transferable image to a transfer material passed between the image carrier and a transfer member that is brought into contact with the image carrier and applied with a bias.

【0002】0002

【従来の技術】図9は転写部材として転写ローラを用い
た画像形成装置の一例の概要図で、本例は電子写真プロ
セス利用のプリンタ又は複写機である。
2. Description of the Related Art FIG. 9 is a schematic diagram of an example of an image forming apparatus using a transfer roller as a transfer member, and this example is a printer or a copying machine using an electrophotographic process.

【0003】1は画像担持体としての回転ドラム型の電
子写真感光体(以下、ドラムと略記する)である。この
ドラム1の周辺には一次帯電器2、画像露光装置3、現
像装置4、転写部材としての転写ローラ5、クリーニン
グ装置6の等の電子写真プロセス機器が配設されている
Reference numeral 1 denotes a rotating drum-type electrophotographic photosensitive member (hereinafter abbreviated as drum) as an image carrier. Electrophotographic process equipment such as a primary charger 2, an image exposure device 3, a developing device 4, a transfer roller 5 as a transfer member, and a cleaning device 6 are arranged around the drum 1.

【0004】14は給紙トレイ、15は該トレイ上に積
載した転写材(以下、紙と記す)、13はその積載紙を
不図示の分離爪等との共働で1枚宛分離して装置内へ給
搬送する給紙ローラであり、装置内へ給送された紙15
はガイド12a→レジストローラ対10・11→転写ガ
イド8・9を経由してドラム1と転写ローラ5との当接
ニップ部(転写部)Nへ搬送される。そして転写部Nを
通った紙はガイド12b→定着器7を経由して排紙トレ
イ16ヘ排出される。17は装置外装である。
14 is a paper feed tray, 15 is a transfer material (hereinafter referred to as paper) stacked on the tray, and 13 is a transfer material that separates the stacked paper into individual sheets by working with a separating claw (not shown) or the like. This is a paper feed roller that feeds and conveys paper into the device, and the paper 15 that is fed into the device.
is conveyed to the abutment nip portion (transfer portion) N between the drum 1 and the transfer roller 5 via the guide 12a → registration roller pair 10 and 11 → transfer guides 8 and 9. Then, the paper that has passed through the transfer section N is discharged to the paper discharge tray 16 via the guide 12b and the fixing device 7. 17 is the exterior of the device.

【0005】本例の画像形成装置は反転現像式のもので
あり、ドラム1の帯電はマイナス帯電、現像剤としての
トナーの電荷(トリボ)も同様にマイナス帯電とする。
The image forming apparatus of this embodiment is of a reversal development type, and the drum 1 is charged with a negative charge, and the charge (triboelectric charge) of the toner as a developer is also charged with a negative charge.

【0006】ドラム1は矢示の時計方向に所定の周速度
(プロセススピード)をもって回転駆動され、この回転
ドラムの表面が一次帯電器2によって所定の暗電位VD
に帯電され、次いでレーザスキャナ等の露光装置3によ
って画像露光がなされて、ドラム1上の露光された部分
は電位VDの絶対値が小さくなり、明電位VLとなって
静電潜像が形成される。
The drum 1 is rotated clockwise as indicated by an arrow at a predetermined circumferential speed (process speed), and the surface of the rotating drum is charged with a predetermined dark potential VD by a primary charger 2.
Then, image exposure is performed by an exposure device 3 such as a laser scanner, and the exposed portion of the drum 1 has a small absolute value of the potential VD, becomes a bright potential VL, and an electrostatic latent image is formed. Ru.

【0007】この潜像は現像装置4によりトナー像とし
て反転現像される。本例の現像装置4は、回転自在に取
り付けられたスリーブ4a上にマイナス帯電されたトナ
ーが薄層コートされており、このスリーブ4aにはドラ
ム1の暗電位VDよりも小さく明電位VLよりも大きな
電圧が印加されていて、スリーブ4a上のトナーはドラ
ム1の明電位VLの部分にのみ転移して潜像が顕像化さ
れる。
[0007] This latent image is reversely developed as a toner image by a developing device 4. In the developing device 4 of this embodiment, a thin layer of negatively charged toner is coated on a rotatably mounted sleeve 4a, and the sleeve 4a has a dark potential VD of the drum 1 which is smaller than the bright potential VL. A large voltage is applied, and the toner on the sleeve 4a is transferred only to the bright potential VL portion of the drum 1, and the latent image is visualized.

【0008】ドラム1上の形成トナー像は、給紙トレイ
14から給紙ローラ13、搬送ガイド12a、一対の上
下レジストローラ10・11、一対の上下転写ガイド8
・9を経て転写部Nへ給搬送された紙15に、プラスの
バイアスを印加された転写ローラ5によって転写される
。トナー像の転写を受けた紙15は、ドラム1から分離
されてガイド12bで定着器7へ導入されてトナー像が
紙面に加熱定着され、排紙トレイ16へ排出される。
The toner image formed on the drum 1 is transferred from a paper feed tray 14 to a paper feed roller 13, a conveyance guide 12a, a pair of upper and lower registration rollers 10 and 11, and a pair of upper and lower transfer guides 8.
- The image is transferred onto the paper 15 fed and conveyed to the transfer unit N via the transfer roller 5 by the transfer roller 5 to which a positive bias is applied. The paper 15 to which the toner image has been transferred is separated from the drum 1 and introduced into the fixing device 7 by the guide 12b, where the toner image is heated and fixed on the paper surface, and then discharged to the paper discharge tray 16.

【0009】一方、ドラム1上に転写されずに残ったト
ナーはクリーニング装置6によって回収され、ドラム1
は清掃されて繰り返して作像に使用される。
On the other hand, the toner remaining on the drum 1 without being transferred is collected by the cleaning device 6 and removed from the drum 1.
is cleaned and used repeatedly for imaging.

【0010】転写ローラ5は、芯金5aと、該芯金に同
心一体に金型成形等でローラ状に形成した弾性層5bと
からなり、ドラム1に対して平行に所定の当接圧をもっ
て当接させてあり、ドラム1と略同じ周速度をもって順
方向に回転する。
The transfer roller 5 is made up of a core metal 5a and an elastic layer 5b formed concentrically with the core metal into a roller shape by molding or the like, and is applied parallel to the drum 1 with a predetermined contact pressure. The drum 1 is brought into contact with the drum 1 and rotates in the forward direction at approximately the same circumferential speed as the drum 1.

【0011】本例の転写ローラ5は、芯金5aは外径φ
8.0、弾性層5bは外径φ20.0mm、ローラ長2
2cmである。弾性層5bは発泡EPDMのゴム材中に
カーボンや酸化亜鉛を添加分散して抵抗値を調整してあ
り、抵抗値は2.5×103Ωcm程度、ゴム硬度は3
0°(アスカC)である。ドラム1に総圧1.5kgで
当接させたときにドラム1と転写ローラ5が形成するニ
ップ部Nの幅は約2.5mmであり、該ニツプ部Nと転
写ローラ芯金5aとの間の抵抗は2×108 Ωである
In the transfer roller 5 of this example, the core metal 5a has an outer diameter φ.
8.0, the outer diameter of the elastic layer 5b is 20.0 mm, and the roller length is 2.
It is 2cm. The elastic layer 5b has a resistance value adjusted by adding and dispersing carbon and zinc oxide into a foamed EPDM rubber material, and the resistance value is approximately 2.5×10 3 Ωcm and the rubber hardness is 3.
0° (Asuka C). The width of the nip N formed between the drum 1 and the transfer roller 5 when they are brought into contact with the drum 1 with a total pressure of 1.5 kg is approximately 2.5 mm, and the width between the nip N and the transfer roller core 5a is approximately 2.5 mm. The resistance of is 2×108 Ω.

【0012】上記のような転写ローラ5を使用して転写
を行う場合には、転写ローラ5に印加するバイアスは2
.8KV程度が適当である。しかし、このような転写ロ
ーラ5は製造時の抵抗値管理が難しく、製造時にその抵
抗値が若干変動する。また、環境、特に雰囲気中の水分
量によって抵抗値が変動する。この抵抗値変動によって
、転写時に転写ローラ5に印加する適正バイアスも変化
する。
When transferring using the transfer roller 5 as described above, the bias applied to the transfer roller 5 is 2.
.. Approximately 8KV is appropriate. However, it is difficult to control the resistance value of such a transfer roller 5 during manufacture, and the resistance value varies slightly during manufacture. Further, the resistance value varies depending on the environment, especially the amount of moisture in the atmosphere. Due to this resistance value variation, the appropriate bias applied to the transfer roller 5 during transfer also changes.

【0013】このような変化のある転写ローラ5につい
ての有効なバイアス制御手段として本出願人は先に特願
昭63−276106号に開示したような制御方法を提
案している。
As an effective bias control means for the transfer roller 5 which undergoes such changes, the present applicant has previously proposed a control method as disclosed in Japanese Patent Application No. 1983-276106.

【0014】この制御方法は、例えば暗電位−700V
の乗っているドラム1に転写ローラ5を当接させ、この
転写ローラ5に定電流バイアスを印加し、このとき発生
する電圧をもとに転写時(通紙時)に転写ローラ5に印
加するバイアスを決定するものである(以下、この制御
方法をATVC法と称する)。転写ローラ5に印加する
定電流バイアスの電流値は、必要に応じて決定すれば良
いが、プロセススピードを94mm/secとして10
〜20μA程度であれば良く、ここでは特に20μAで
行うものとする。
[0014] This control method uses, for example, a dark potential of -700V.
The transfer roller 5 is brought into contact with the drum 1 on which the paper is placed, and a constant current bias is applied to the transfer roller 5. Based on the voltage generated at this time, the voltage is applied to the transfer roller 5 during transfer (when paper passes). This control method is used to determine the bias (hereinafter, this control method will be referred to as the ATVC method). The current value of the constant current bias applied to the transfer roller 5 may be determined as necessary, but it is determined that the current value of the constant current bias applied to the transfer roller 5 is
It is sufficient if the current is about 20 μA, and in this case, 20 μA is used in particular.

【0015】この場合の転写ローラ5に印加するバイア
スと電流の関係を図10に示す。この図10は通常環境
(20℃・60%RH)における転写ローラ5に印加す
るバイアス電圧Vと電流Iの関係を示す図(V−I特性
図)であり、図中のIDは非通紙時の転写ローラ電圧に
対する転写ローラ電流、IPは通紙時の転写ローラ電流
である。非通紙時の転写ローラ電流IDが20μAのと
き、電圧Vは2.8KVとなり、通紙時の転写ローラ電
流IPは7μAとなる。この転写ローラ電流が7μA以
上であれば、電流不足による転写不良は発生しない。
FIG. 10 shows the relationship between the bias applied to the transfer roller 5 and the current in this case. FIG. 10 is a diagram (VI characteristic diagram) showing the relationship between the bias voltage V applied to the transfer roller 5 and the current I in a normal environment (20° C., 60% RH), and ID in the diagram is a non-paper-passing diagram. The transfer roller current with respect to the transfer roller voltage at the time, IP is the transfer roller current at the time of paper passing. When the transfer roller current ID when the paper is not passing is 20 μA, the voltage V is 2.8 KV, and the transfer roller current IP when the paper is passing is 7 μA. If this transfer roller current is 7 μA or more, transfer failures due to insufficient current will not occur.

【0016】図11の(a)と(b)は夫々非通紙時と
通紙時の転写装置の等価回路を示すもので、R1はドラ
ム1の抵抗(ドラムの感光体のVD電位の抵抗)、R5
は転写ローラ5の芯金5aと転写ローラ5とドラム1で
形成するニップ部Nの間の抵抗(転写ローラのゴム材の
抵抗)である。
FIGS. 11(a) and 11(b) show equivalent circuits of the transfer device when paper is not passing and when paper is passing, respectively, and R1 is the resistance of the drum 1 (the resistance of the VD potential of the photoreceptor of the drum). ), R5
is the resistance between the core metal 5a of the transfer roller 5 and the nip portion N formed by the transfer roller 5 and the drum 1 (resistance of the rubber material of the transfer roller).

【0017】R15は転写材である紙15の抵抗、Vは
転写ローラ5に給電する電源電圧、20はアース、ID
は非通紙時の転写電圧を決定するための定電流バイアス
印加時の電流であり、ここでは20μA、IPは転写時
の電流で7μAである。
R15 is the resistance of the paper 15 that is the transfer material, V is the power supply voltage that supplies power to the transfer roller 5, 20 is the ground, and ID
is the current when a constant current bias is applied to determine the transfer voltage when paper is not passing, and is 20 μA here, and IP is the current during transfer, which is 7 μA.

【0018】ここで、上記抵抗R1は2×107 Ω、
抵抗R5はV=2.8KVとすると約1.2×108 
Ω、抵抗R15=2.6×108 Ωである。まず、図
11の(a)に示すように非通紙時に電流ID=20μ
Aの定電流バイアスを転写ローラ5に印加して電圧をホ
ールドすると、通紙時には(b)に示すように紙15が
抵抗R15として作用し、電流IPは7μAとなる。
Here, the resistance R1 is 2×10 7 Ω,
Resistor R5 is approximately 1.2×108 when V=2.8KV
Ω, and resistance R15=2.6×10 8 Ω. First, as shown in FIG. 11(a), the current ID=20μ when paper is not passing.
When a constant current bias of A is applied to the transfer roller 5 and the voltage is held, the paper 15 acts as a resistor R15 as shown in (b) during paper passing, and the current IP becomes 7 μA.

【0019】[0019]

【発明が解決しようとする課題】しかしながら上記従来
装置ではAVTC法で環境による転写ローラ5の抵抗値
変化に伴う電圧制御はできても、転写材、特に紙15の
抵抗値R15の変化に対応した電圧の制御がなされない
ため、高湿環境では必要以上の電圧を印加することにな
るという問題があった。
[Problems to be Solved by the Invention] However, in the above-mentioned conventional apparatus, although it is possible to control the voltage according to changes in the resistance value of the transfer roller 5 due to the environment using the AVTC method, it is difficult to cope with changes in the resistance value R15 of the transfer material, especially the paper 15. Since the voltage is not controlled, there is a problem in that a voltage higher than necessary is applied in a high humidity environment.

【0020】例えば、高温高湿32℃・85%の環境で
抵抗値2×108 Ω(抵抗測定電圧2KV)の転写ロ
ーラ5を使用し、この環境に長期間放置して充分吸湿し
た紙15に転写を行う場合のV−I特性を図12に示す
。 IHは吸湿紙に転写を行う場合のV−I特性である。紙
15が吸湿している場合、紙の抵抗が下るので転写電流
7μAを得るための電圧は2KV程度で良いのに、この
場合には通紙時10μA以上の電流が流れている。これ
は図11の(b)に示す等価回路で抵抗R15が小さく
なったことに等しい。
For example, if a transfer roller 5 with a resistance value of 2×10 8 Ω (resistance measurement voltage 2 KV) is used in an environment of high temperature and high humidity of 32° C. and 85%, the paper 15 that has been left in this environment for a long period of time and has sufficiently absorbed moisture is transferred. FIG. 12 shows the VI characteristics when transferring. IH is the VI characteristic when transferring to moisture-absorbing paper. When the paper 15 absorbs moisture, the resistance of the paper decreases, so the voltage required to obtain a transfer current of 7 μA may be about 2 KV, but in this case, a current of 10 μA or more flows during paper passing. This is equivalent to the resistance R15 becoming smaller in the equivalent circuit shown in FIG. 11(b).

【0021】このように高湿環境においては必要以上に
電圧を上げるので高圧電源の負担が大きくなる。また、
画像担持体としてのドラム1に大きな電流を流すことに
なるので、ドラム1の電気的な劣化を早く招来すること
になる。しかも、転写電流によりドラム電位を下げてし
まうために発生する地カブリ(紙跡)のマージンも小さ
くなるといった不都合があった。
[0021] In this way, in a high-humidity environment, the voltage is increased more than necessary, which increases the burden on the high-voltage power supply. Also,
Since a large current is passed through the drum 1 as an image carrier, electrical deterioration of the drum 1 is caused quickly. Moreover, since the drum potential is lowered by the transfer current, the margin for background fog (paper traces) that occurs is also disadvantageously reduced.

【0022】本発明は同じくATVC法で転写部材に対
する電圧制御をするものであるが、転写材が吸湿して抵
抗が低下していても上記のような不具合なく画像転写を
実行させることができるようにした画像形成装置の転写
装置を提供することを目的とする。
The present invention similarly uses the ATVC method to control the voltage applied to the transfer member, but it is possible to perform image transfer without the above-mentioned problems even if the transfer material absorbs moisture and its resistance decreases. An object of the present invention is to provide a transfer device for an image forming apparatus.

【0023】[0023]

【課題を解決しようとする手段】本発明は、画像担持体
面に、該画像担持体面を所定の暗電位に帯電する工程を
含む作像プロセスにより可転写画像を形成担持させ、該
可転写画像を、該画像担持体と該画像担持体に当接させ
てバイアスを印加した転写部材との間に通紙した転写材
へ転写させ、この通紙転写時の転写部材に対するバイア
ス印加を、非通紙時に画像担持体面の暗電位部に当接の
転写部材に定電流のバイアスを印加し、そのとき発生す
る電圧をもとに通紙転写時の転写電圧を決定して定電圧
制御する画像形成装置の転写装置において、高湿環境の
非通紙時に前記転写部材に定電流のバイアスを印加した
ときに該転写部材から電流の流れ込みを生じるような転
写部材近傍位置にバイアス電圧(0Vも含む)を印加し
た電極部材を配置したことを特徴とする画像形成装置の
転写装置である。
[Means for Solving the Problems] The present invention forms and carries a transferable image on the surface of an image carrier by an image forming process that includes a step of charging the surface of the image carrier to a predetermined dark potential, and the transferable image is , the image is transferred to a transfer material that passes between the image carrier and a transfer member that is in contact with the image carrier and a bias is applied, and the bias application to the transfer member at the time of paper passing transfer is changed to a non-paper passing transfer member. An image forming apparatus that controls a constant voltage by applying a constant current bias to a transfer member that is in contact with the dark potential portion of the image carrier surface, and determining the transfer voltage during paper transfer based on the voltage generated at that time. In this transfer device, a bias voltage (including 0 V) is applied to a position near the transfer member such that a current flows from the transfer member when a constant current bias is applied to the transfer member when paper is not passing in a high humidity environment. This is a transfer device of an image forming apparatus characterized by disposing an electrode member to which an applied voltage is applied.

【0024】[0024]

【作用】即ち、高湿環境下では転写部材から該転写部材
に近接の電極部材に電流が流れることで転写時の電圧が
低くなり、ATVC制御を行なったときにホールド電圧
を下げて必要以上に転写電流を増大させることがなくな
り、これにより転写材が高湿環境下で吸湿して抵抗の低
下した紙でも過大電流を流さずにを転写することができ
、高圧電源の負荷が小さくできる、像担持体の劣化の進
行を遅くすることができるようになる。
[Operation] In other words, in a high humidity environment, current flows from the transfer member to the electrode member close to the transfer member, which lowers the voltage during transfer, and when ATVC control is performed, the hold voltage is lowered and the voltage is lowered than necessary. This eliminates the need to increase the transfer current, making it possible to transfer images even on paper whose resistance has decreased due to moisture absorption in a high-humidity environment, without passing an excessive current, reducing the load on the high-voltage power supply. This makes it possible to slow down the progress of deterioration of the carrier.

【0025】[0025]

【実施例】〈第1実施例〉(図1〜3)図1は第1実施
例装置の要部の概略図であり、19は画像担持体として
のドラム1に当接させた転写部材としての転写ローラ5
の芯金5aにバイアス電圧を印加する電源、21は転写
ローラ5に近接配置した電極板、22は該電極板21に
バイアス電圧を印加する電源である。転写ローラ5の外
径は20mm、長さは22cm、転写ローラ5と電極板
21との対向面積は20cm2 、電極板21は転写ロ
ーラ5とのギャップ2mmで保持されている。電極板2
1の転写ローラ5に対する対向面積、電源22の電圧V
22は実験等により任意に設定すれば良い。本実施例で
は、転写ローラ5から電極板21への電流リークを促進
するために、電極板21には転写ローラに対する対向表
面に先端の尖った突起部21aを形成してあるが、この
突起21aは特には無くても良い。
[Example] <First Example> (Figs. 1 to 3) Fig. 1 is a schematic diagram of the main parts of the apparatus of the first example, and 19 is a transfer member brought into contact with the drum 1 as an image carrier. transfer roller 5
21 is an electrode plate disposed close to the transfer roller 5; 22 is a power source that applies a bias voltage to the electrode plate 21; The outer diameter of the transfer roller 5 is 20 mm, the length is 22 cm, the opposing area between the transfer roller 5 and the electrode plate 21 is 20 cm 2 , and the electrode plate 21 is held with a gap of 2 mm from the transfer roller 5. Electrode plate 2
1 facing the transfer roller 5, the voltage V of the power supply 22
22 may be arbitrarily set by experiment or the like. In this embodiment, in order to promote current leakage from the transfer roller 5 to the electrode plate 21, a sharp protrusion 21a is formed on the surface of the electrode plate 21 facing the transfer roller. It doesn't really need to be.

【0026】なお、ドラム1の周囲や所要部所には前述
図9と同様に所要の作像プロセス機器が配設されて画像
形成装置が構成されているが図1にはそれらは省略した
It should be noted that the image forming apparatus is constructed by disposing necessary image forming process equipment around the drum 1 and at necessary parts as shown in FIG. 9, but these are omitted in FIG.

【0027】本実施例では高湿環境32℃・85%とし
、ドラム1の電位VD−700V、2KVのバイアス電
圧印加時における転写ローラ5の抵抗を2.0×108
 Ωとする。ここで、転写ローラ5のバイアス電圧を印
加するために、非通紙時に電源19より定電流バイアス
(20μA)が転写ローラ5の芯金5aに印加されるが
、転写ローラ5の近傍には電極板21があり、この電極
板21には転写ローラ5のバイアス電源19とは反対の
極性のバイアス電圧−2KV程度が電源22より印加さ
れている。この状態を等価回路に示すと図2のようにな
る。
In this embodiment, the high humidity environment is 32° C. and 85%, and the resistance of the transfer roller 5 is 2.0×10 8 when the potential of the drum 1 is VD-700V and a bias voltage of 2KV is applied.
Let it be Ω. Here, in order to apply a bias voltage to the transfer roller 5, a constant current bias (20 μA) is applied from the power supply 19 to the core bar 5a of the transfer roller 5 when the paper is not passing. There is a plate 21, to which a bias voltage of approximately -2 KV of polarity opposite to that of the bias power source 19 of the transfer roller 5 is applied from a power source 22. This state is shown in an equivalent circuit as shown in FIG.

【0028】図2において、R21は転写ローラ5の芯
金5aと電極板21との間の抵抗であり、転写ローラ5
のゴム材及び転写ローラ5と電極板21の空間ギャップ
の抵抗を含むものである。V22は電源22のバイアス
電圧、IDは転写ローラ5からドラム1に流れる電流、
Iaは転写ローラ5から電極板21に流れる電流である
In FIG. 2, R21 is the resistance between the core metal 5a of the transfer roller 5 and the electrode plate 21, and
This includes the resistance of the rubber material and the space gap between the transfer roller 5 and the electrode plate 21. V22 is the bias voltage of the power supply 22, ID is the current flowing from the transfer roller 5 to the drum 1,
Ia is a current flowing from the transfer roller 5 to the electrode plate 21.

【0029】通常環境(20℃・60%)の場合には抵
抗R21は非常に大きく、電流Iaは0に近いが、高湿
環境の場合には抵抗R21は小さくなり、電流Iaが大
きくなってくる。この高湿環境における通紙時、非通紙
時のV−I特性を図3に示す。ID+Iaは非通紙時に
電極板21にバイアス電圧が印加された状態でのV−I
特性で、このとき転写ローラ5に20μA流れるときの
電圧がホールドされる。この場合は2KVとなる。
In a normal environment (20° C., 60%), the resistance R21 is very large and the current Ia is close to 0, but in a high humidity environment, the resistance R21 becomes small and the current Ia becomes large. come. FIG. 3 shows the VI characteristics when paper is passed and when paper is not passed in this high humidity environment. ID+Ia is V-I when a bias voltage is applied to the electrode plate 21 when paper is not passed.
As a characteristic, the voltage at which 20 μA flows through the transfer roller 5 at this time is held. In this case, it is 2KV.

【0030】一方、吸湿紙の通紙時に電圧と転写ローラ
5からドラム1へ流れる電流のV−I特性はIHのよう
になり、転写ローラ5に印加されたバイアス電圧が2K
Vのときの電流は7μAとなり、過大な電流が流れるこ
とはない。
On the other hand, the V-I characteristic of the voltage and the current flowing from the transfer roller 5 to the drum 1 when the moisture-absorbing paper is passed is as shown by IH, and the bias voltage applied to the transfer roller 5 is 2K.
The current at V is 7 μA, and no excessive current flows.

【0031】また、通常環境の場合には抵抗R21は非
常に大きく、電流Iaはほぼ0なので、転写時の電圧降
下は起こらず、湿度が高くなった場合には、その湿度に
応じて転写ローラ5への印加電圧を下げることができる
Furthermore, in a normal environment, the resistance R21 is very large and the current Ia is almost 0, so no voltage drop occurs during transfer, and if the humidity becomes high, the transfer roller will change depending on the humidity. The voltage applied to 5 can be lowered.

【0032】〈第2実施例〉(図4〜7)転写部材に対
する近接電極部材は専用の電極部材を配設しなくとも画
像形成装置の構成部品として装置内にある機能パーツを
電極部材に兼用させてそれに転写ローラ5からの電流を
流し込ませて前記第1実施例における電極板21を設け
た場合と同様の制御を行なわせることもできる。
<Second Embodiment> (FIGS. 4 to 7) The electrode member close to the transfer member does not need to be provided with a dedicated electrode member, and a functional part inside the image forming apparatus can also be used as the electrode member. It is also possible to perform the same control as in the case where the electrode plate 21 in the first embodiment is provided by causing the current from the transfer roller 5 to flow therein.

【0033】図4はその例を示すもので、除電針を電極
部材に兼用させたものである。即ち24は転写ローラ5
の近傍(例えば近接距離1mm)に設けられた除電針、
25は除電針24を被覆している絶縁部材、26は除電
針25にバイアス電圧を印加する電源である。
FIG. 4 shows an example of this, in which the static eliminating needle is also used as an electrode member. That is, 24 is the transfer roller 5
A static elimination needle provided near (for example, a proximity distance of 1 mm)
25 is an insulating member covering the static eliminating needle 24, and 26 is a power source that applies a bias voltage to the static eliminating needle 25.

【0034】上記除電針24は本来、低湿環境での紙1
5の帯電により生じる紙搬送の不安定を改善するため、
紙15を除電する目的で設けられているので、一般に転
写バイアスと逆極性のバイアスが印加される(0Vも含
む)。本実施例はこの除電針25を高温時に転写ローラ
5から電流を流し込ませる電極部材に兼用させたもので
あり、この除電針24に電源26から−2.5KVの電
圧を印加した。
The static eliminating needle 24 is originally used for cleaning paper 1 in a low humidity environment.
In order to improve the instability of paper conveyance caused by electrification in step 5,
Since it is provided for the purpose of neutralizing the paper 15, a bias of polarity opposite to the transfer bias is generally applied (including 0 V). In this embodiment, the static eliminating needle 25 is also used as an electrode member through which a current flows from the transfer roller 5 at high temperatures, and a voltage of -2.5 KV is applied to the static eliminating needle 24 from the power source 26.

【0035】一般に除電針24は絶縁部材25によりそ
の先端部以外が覆われ、除電針先端部の紙15と対向す
る部分からのみ電流が流れ込むような構成となっている
が、本実施例では高湿環境において、転写ローラ5から
除電針24に積極的に電流を流し込むため、転写ローラ
5と対向する絶縁部材部分を2点鎖線示25aのように
大きく切り欠いてある。
Generally, the static eliminating needle 24 is covered with an insulating member 25 except for its tip, and is configured such that current flows only from the portion of the distal end of the static eliminating needle that faces the paper 15. In order to actively flow current from the transfer roller 5 to the static elimination needle 24 in a humid environment, the portion of the insulating member facing the transfer roller 5 is largely cut out as indicated by a two-dot chain line 25a.

【0036】図5は本実施例装置の非通紙時における等
価回路を示すもので、R24は除電針24と転写ローラ
5の芯金5aの間の抵抗、V26は除電針バイアス電源
26の電圧、Ibは転写ローラ5の芯金5aから除電針
24に流れる電流であり、この電流Ibは低湿環境・通
常環境では略0であるが、高湿環境になると大きくなっ
てくる。
FIG. 5 shows an equivalent circuit of the apparatus of this embodiment when paper is not passing, where R24 is the resistance between the static elimination needle 24 and the core bar 5a of the transfer roller 5, and V26 is the voltage of the static elimination needle bias power supply 26. , Ib is a current flowing from the core metal 5a of the transfer roller 5 to the static elimination needle 24. This current Ib is approximately 0 in a low humidity environment or a normal environment, but increases in a high humidity environment.

【0037】このため、32℃・85%の高湿環境下で
20μAの定電流制御を行った場合には図6に示すよう
なV−I特性となる。IDはドラム1に流れる電流、I
D+Ibは転写ローラ5の芯金5aからドラム1及び除
電針24に流れる電流の和であり、この電流の和ID+
Ib=20μのとき、転写ローラ5に印加されるバイア
ス電圧は2KVとなる。
Therefore, when a constant current control of 20 μA is performed in a high humidity environment of 32° C. and 85%, the V-I characteristic as shown in FIG. 6 is obtained. ID is the current flowing through drum 1, I
D+Ib is the sum of the currents flowing from the core metal 5a of the transfer roller 5 to the drum 1 and the static elimination needle 24, and the sum of this current ID+
When Ib=20μ, the bias voltage applied to the transfer roller 5 is 2KV.

【0038】図7は通紙時の等価回路を示すもので、R
15はドラム1と転写ローラ5のニップ部の紙15の抵
抗、IHはニップ部を流れる電流、R15′は転写ロー
ラ5と除電針24の間の紙15の抵抗、Icは転写ロー
ラ5と除電針24を流れる電流である。このように通紙
時の電流は紙15を介してドラム1へ流れるものと、空
気中を伝って除電針24の流れるものとに分けることが
できる。この場合のV−I特性を前記図6に示す。紙1
5を介してドラム1へ流れる電流IHは転写ローラ5に
2KVのバイアス電圧印加時7μAであるが、転写ロー
ラ5からの電流はIH(7μA)+Ib(8μA)+I
c(4μA)となるため、19μAとなっている。
FIG. 7 shows an equivalent circuit when paper is passed, and R
15 is the resistance of the paper 15 at the nip between the drum 1 and the transfer roller 5, IH is the current flowing through the nip, R15' is the resistance of the paper 15 between the transfer roller 5 and the static elimination needle 24, and Ic is the resistance between the transfer roller 5 and the static elimination This is the current flowing through the needle 24. In this way, the current during paper passing can be divided into one that flows to the drum 1 via the paper 15 and one that flows through the static eliminating needle 24 through the air. The VI characteristic in this case is shown in FIG. 6. paper 1
The current IH flowing to the drum 1 via the transfer roller 5 is 7 μA when a bias voltage of 2 KV is applied to the transfer roller 5, but the current from the transfer roller 5 is IH (7 μA) + Ib (8 μA) + I
c (4 μA), so the current is 19 μA.

【0039】以上のように除電針24が転写ローラ5に
対する近接電極として兼用されて、低湿環境での紙搬送
性を安定させながら、同時に高湿環境において、紙15
を介してドラム1に流れる電流を小さくできる。
As described above, the static eliminating needle 24 is also used as a proximal electrode for the transfer roller 5, and while stabilizing the paper conveyance in a low humidity environment, it also serves as a proximal electrode for the paper 15 in a high humidity environment.
The current flowing to the drum 1 through the drum 1 can be reduced.

【0040】〈第3実施例〉(図8)本実施例はレジス
トローラ対10・11からの紙15をドラム1と転写ロ
ーラ5との圧接ニップ部(転写部)Nへ案内する一対の
上下の転写ガイド8・9の一方の下転写ガイド8を転写
ローラ5に対する近接電極部材として利用したものであ
る。この転写下ガイド8は転写材である紙15をドラム
1と転写ローラ5のニップ部N近くまで導くためにその
先端部を転写ローラ5に近接させてある。本実施例では
その転写下ガイド8の先端部を、転写ローラ5との対向
面積を大きくするために転写ローラ5の弧に沿って下向
きに折曲げ成形8aしているが、この形状は図示の形状
に限定されるものではない。
Third Embodiment (FIG. 8) In this embodiment, a pair of upper and lower rollers guide the paper 15 from the pair of registration rollers 10 and 11 to the pressure nip (transfer section) N between the drum 1 and the transfer roller 5. The lower transfer guide 8 of one of the transfer guides 8 and 9 is used as a proximal electrode member for the transfer roller 5. The lower transfer guide 8 has its leading end close to the transfer roller 5 in order to guide the paper 15, which is the transfer material, close to the nip N between the drum 1 and the transfer roller 5. In this embodiment, the tip of the lower transfer guide 8 is bent downward along the arc of the transfer roller 5 in order to increase the area facing the transfer roller 5, but this shape is not the same as shown in the figure. It is not limited to the shape.

【0041】本実施例ではこの転写下ガイド8を接地し
たが、転写バイアスと異なる極性のバイアスを印加して
も良いことは勿論である。また転写下ガイド8は紙15
の搬送を円滑に行うとともに、高湿環境下で転写ローラ
5から電流が流れ込むように先端部をできるだけ転写ロ
ーラ5に近接させて配設する。ここでは転写下ガイド8
と転写ローラ5の距離は0.5mmとする。
In this embodiment, the lower transfer guide 8 is grounded, but it goes without saying that a bias having a polarity different from the transfer bias may be applied. Also, the lower transfer guide 8 is the paper 15
The tip is disposed as close to the transfer roller 5 as possible so that the transfer roller 5 can be smoothly conveyed and a current can flow from the transfer roller 5 in a high humidity environment. Here, lower transfer guide 8
The distance between the transfer roller 5 and the transfer roller 5 is 0.5 mm.

【0042】以上のような構成にすることにより、転写
下ガイド8が転写ローラ5に対する近接電極として兼用
されて、高湿環境において紙15を介してドラム1に流
れる電流を小さくできる。
With the above configuration, the lower transfer guide 8 is also used as a proximal electrode for the transfer roller 5, and the current flowing to the drum 1 through the paper 15 can be reduced in a high humidity environment.

【0043】[0043]

【発明の効果】以上のように本発明によれば、非通紙時
に転写部材に定電流バイアスを印加してこのとき発生す
る電圧をもとに転写時(通紙時)における転写部材の印
加電圧を決定する転写装置において、転写部材の近傍に
バイアスを印加した電極部材を設けて高湿環境下ではこ
の電極部材に転写部材から電流が流れ込むように構成し
たことで、高湿環境下で吸湿し抵抗値が低下した転写材
に転写する場合でも、転写時の電圧が低くなり過大電流
をが流さずに転写することができるとともに、電圧電源
の負荷を小さくでき、また感光体等の画像担持体の劣化
の進行を遅くすることができるという効果がある。
As described above, according to the present invention, a constant current bias is applied to the transfer member when paper is not passing, and the voltage applied to the transfer member during transfer (when paper is passing) is applied based on the voltage generated at this time. In the transfer device that determines the voltage, an electrode member to which a bias is applied is provided near the transfer member, and a current flows from the transfer member into this electrode member in a high humidity environment. However, even when transferring to a transfer material with a reduced resistance value, the voltage at the time of transfer is lowered, making it possible to transfer without excessive current flowing, reducing the load on the voltage power supply, and reducing the image bearing capacity of the photoreceptor, etc. It has the effect of slowing down the progression of body deterioration.

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

【図1】    第1実施例装置の概略図[Figure 1] Schematic diagram of the first embodiment device

【図2】  
  等価回路図
[Figure 2]
Equivalent circuit diagram

【図3】    高湿環境におけるV−I特性図[Figure 3] VI characteristic diagram in high humidity environment

【図4
】    第2実施例装置の概略図
[Figure 4
] Schematic diagram of the second embodiment device

【図5】    非
通紙時の等価回路図
[Figure 5] Equivalent circuit diagram when paper is not passing

【図6】    高湿環境における
V−I特性図
[Figure 6] VI characteristic diagram in high humidity environment

【図7】    通紙時の等価回路図[Figure 7] Equivalent circuit diagram when passing paper

【図8】    第3実施例装置の概略図[Figure 8] Schematic diagram of the third embodiment device

【図9】  
  画像形成装置の一例の概略図
[Figure 9]
Schematic diagram of an example of an image forming apparatus

【図10】  通常環
境におけるV−I特性図
[Figure 10] VI characteristic diagram in normal environment

【図11】  (a)・(b)
はそれぞれ非通紙時と通紙時の等価回路図
[Figure 11] (a) and (b)
are equivalent circuit diagrams when paper is not passing and when paper is passing, respectively.

【図12】  吸湿紙に転写する場合のV−I特性図[Figure 12] VI characteristic diagram when transferring to moisture absorbing paper

【符号の説明】[Explanation of symbols]

1  ドラム(画像担持体) 5  転写ローラ(転写部材) 8  転写下ガイド(電極部材兼用) 15  紙(転写材) 21  電極板(電極部材) 24  除電針(電極部材兼用) 1 Drum (image carrier) 5 Transfer roller (transfer member) 8 Lower transfer guide (also serves as electrode member) 15 Paper (transfer material) 21 Electrode plate (electrode member) 24 Static elimination needle (also serves as electrode member)

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】画像担持体面に、該画像担持体面を所定の
暗電位に帯電する工程を含む作像プロセスにより可転写
画像を形成担持させ、該可転写画像を、該画像担持体と
該画像担持体に当接させてバイアスを印加した転写部材
との間に通紙した転写材へ転写させ、この通紙転写時の
転写部材に対するバイアス印加を、非通紙時に画像担持
体面の暗電位部に当接の転写部材に定電流のバイアスを
印加し、そのとき発生する電圧をもとに通紙転写時の転
写電圧を決定して定電圧制御する画像形成装置の転写装
置において、高湿環境の非通紙時に前記転写部材に定電
流のバイアスを印加したときに該転写部材から電流の流
れ込みを生じるような転写部材近傍位置にバイアス電圧
を印加した電極部材を配置した、ことを特徴とする画像
形成装置の転写装置。
1. A transferable image is formed and carried on the surface of an image carrier by an image forming process that includes a step of charging the surface of the image carrier to a predetermined dark potential, and the transferable image is transferred between the image carrier and the image. The image is transferred to the transfer material passed between the transfer member that is brought into contact with the carrier and a bias is applied, and the bias applied to the transfer member during the paper transfer is applied to the dark potential portion of the image carrier surface when the paper is not passed. In a transfer device of an image forming apparatus, a constant current bias is applied to the transfer member in contact with the transfer member, and the transfer voltage during paper transfer is determined based on the voltage generated at that time to control the constant voltage. An electrode member to which a bias voltage is applied is arranged at a position near the transfer member such that a current flows from the transfer member when a constant current bias is applied to the transfer member when paper is not passing through the transfer member. Transfer device of image forming device.
JP3104957A 1991-03-08 1991-03-08 Transfer device for image forming device Pending JPH04281486A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3104957A JPH04281486A (en) 1991-03-08 1991-03-08 Transfer device for image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3104957A JPH04281486A (en) 1991-03-08 1991-03-08 Transfer device for image forming device

Publications (1)

Publication Number Publication Date
JPH04281486A true JPH04281486A (en) 1992-10-07

Family

ID=14394579

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3104957A Pending JPH04281486A (en) 1991-03-08 1991-03-08 Transfer device for image forming device

Country Status (1)

Country Link
JP (1) JPH04281486A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001265133A (en) * 2000-03-21 2001-09-28 Sharp Corp Image forming device
JP2012048235A (en) * 2010-08-26 2012-03-08 Xerox Corp Image transfer nip method and apparatus using constant current controls

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001265133A (en) * 2000-03-21 2001-09-28 Sharp Corp Image forming device
JP2012048235A (en) * 2010-08-26 2012-03-08 Xerox Corp Image transfer nip method and apparatus using constant current controls

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