JP2001117317A - Image forming device - Google Patents

Image forming device

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Publication number
JP2001117317A
JP2001117317A JP30150899A JP30150899A JP2001117317A JP 2001117317 A JP2001117317 A JP 2001117317A JP 30150899 A JP30150899 A JP 30150899A JP 30150899 A JP30150899 A JP 30150899A JP 2001117317 A JP2001117317 A JP 2001117317A
Authority
JP
Japan
Prior art keywords
intermediate transfer
image
primary intermediate
transferred
transfer member
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
JP30150899A
Other languages
Japanese (ja)
Inventor
Toshihiko Mihashi
利彦 三橋
Tadashi Kaeriyama
忠士 歸山
Ryuichi Yamamoto
隆一 山本
Yusuke Kitagawa
裕介 北河
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.)
Fujifilm Business Innovation Corp
Original Assignee
Fuji Xerox Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fuji Xerox Co Ltd filed Critical Fuji Xerox Co Ltd
Priority to JP30150899A priority Critical patent/JP2001117317A/en
Publication of JP2001117317A publication Critical patent/JP2001117317A/en
Pending legal-status Critical Current

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  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Color Electrophotography (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device that the occurrence of a 'transfer ghost' or a variation in density is surely prevented and a color image of a high image quality is formed by greatly improving transfer efficiency even when a driving system is simplified, the device is made smaller or a service life of an image carrier such as a photoreceptor is prolonged. SOLUTION: The device is constituted so that a resistance value of a secondary intermediate transfer body where a toner image is transferred from a primary intermediate transfer body is set to be higher than a resistance value of the primary intermediate transfer body where the toner image is transferred from the image carrier.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】この発明は、電子写真記録方
式、静電記録方式、イオノグラフィー、磁気記録方式等
の画像形成方式を採用する画像形成装置に係り、特に、
各々色の異なる単色トナー像を形成する複数の画像形成
ユニットを備え、これら複数の画像形成ユニットで形成
された各々色の異なる単色トナー像を、中間転写体上に
一旦転写した後、最終的に記録媒体上に重ね合わせた状
態で一括して転写・定着することによりカラー画像を形
成する画像形成装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus employing an image forming system such as an electrophotographic recording system, an electrostatic recording system, an ionography, and a magnetic recording system.
A plurality of image forming units each forming a single-color toner image of a different color are provided, and the single-color toner images of the different colors formed by the plurality of image forming units are once transferred onto an intermediate transfer body, and finally, The present invention relates to an image forming apparatus that forms a color image by collectively transferring and fixing in a state of being superimposed on a recording medium.

【０００２】[0002]

【従来の技術】従来、上記電子写真記録方式等を採用し
た画像形成装置において、カラー画像を高速かつ高画質
に形成可能とした装置としては、イエロー、マゼンタ、
シアン、黒の各単色トナー像を形成する４つの画像形成
ユニットを、互いに並列的に配置し、これらの各画像形
成ユニットで順次形成されるイエロー、マゼンタ、シア
ン、黒の各単色トナー像を、転写材搬送ベルト上に担持
された転写用紙上に直接多重に転写するか、中間転写ベ
ルト上に一旦多重に転写した後、この中間転写ベルトか
ら転写用紙上に一括して転写し、転写用紙上にトナー像
を定着することによって、カラー画像を形成するように
構成された画像形成装置が、種々提案されており、実際
に製品化されてきてもいる。2. Description of the Related Art Heretofore, in an image forming apparatus employing the above-described electrophotographic recording method, devices capable of forming a color image with high speed and high image quality include yellow, magenta, and the like.
Four image forming units that form cyan and black single-color toner images are arranged in parallel with each other, and yellow, magenta, cyan, and black single-color toner images sequentially formed by these image forming units are formed. After multiple transfer directly onto the transfer paper carried on the transfer material transport belt, or once on the intermediate transfer belt, the image is transferred collectively onto the transfer paper from this intermediate transfer belt. Various image forming apparatuses configured to form a color image by fixing a toner image to a toner image have been proposed and actually commercialized.

【０００３】ところで、かかる画像形成装置の場合に
は、可撓性部材からなる転写材搬送ベルトや、同じく可
撓性部材からなる中間転写ベルトを使用するものである
が、これらの転写材搬送ベルトや中間転写ベルトは、イ
エロー、マゼンタ、シアン、黒の４つの画像形成ユニッ
トに渡って循環駆動されるように、複数のロール間に張
架されるため、駆動系が複雑となるとともに、可撓性部
材からなるため、蛇行が生じたり、温度変化等によって
伸縮が生じ、画像の位置ずれを防止するための技術が必
須となり、更に、転写材搬送ベルトや中間転写ベルト
は、４つの画像形成ユニットに渡って張架されるため、
装置が大型化するという課題を有していた。In the case of such an image forming apparatus, a transfer material transport belt made of a flexible member or an intermediate transfer belt made of a flexible member is used. The intermediate transfer belt and the intermediate transfer belt are stretched between a plurality of rolls so as to be circulated and driven across four image forming units of yellow, magenta, cyan, and black. Since it is made of a flexible material, meandering occurs, expansion and contraction occurs due to temperature change, etc., and a technique for preventing image displacement is indispensable. Further, the transfer material transport belt and the intermediate transfer belt have four image forming units. To be stretched over,
There was a problem that the device became large.

【０００４】そこで、本出願人は、特開平１０−７８６
８６号公報に開示されているように、上記の課題を解決
し、駆動系の構成を簡易化することができるとともに、
装置の小型化が可能であり、しかも複雑な画像の位置ず
れを防止技術を用いることなく、高画質のカラー画像を
形成することが可能な画像形成装置について、既に提案
している。Accordingly, the present applicant has disclosed in Japanese Patent Application Laid-Open No. H10-786.
As disclosed in Japanese Patent Publication No. 86, the above problems can be solved, and the configuration of the drive system can be simplified.
An image forming apparatus that can be downsized and that can form a high-quality color image without using a technique for preventing a complicated image misalignment has already been proposed.

【０００５】この特開平１０−７８６８６号公報に開示
された画像形成装置は、種々の実施の形態を含むもので
あるが、その実施の形態の１つとして、図１１に示すよ
うに、２つの感光体１１０、１２０と１つの転写中間体
１５１とからなる単位構成体と、２つの感光体１３０、
１４０と１つの転写中間体１５２とからなる単位構成体
が備えられており、２つの転写中間体１５１、１５２
は、さらにもう１つの転写中間体１５３に接するように
構成したものが提案されている。ここに示された４つの
感光体は共通の接線を有しており、したがって、これら
の４つの感光体の周囲に配置された帯電装置、露光装
置、現像装置、クリーニング装置は、それぞれの感光体
に対し同一位置に配置されており、各装置種類毎に装置
の共通化が図られている。The image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 10-78686 includes various embodiments. One of the embodiments is, as shown in FIG. A unit structure composed of 110 and 120 and one transfer intermediate 151;
A unit structure including a transfer intermediate 140 and one transfer intermediate 152 is provided, and two transfer intermediates 151 and 152 are provided.
Has been proposed so as to be in contact with yet another transfer intermediate 153. The four photoconductors shown here have a common tangent line, and therefore, a charging device, an exposure device, a developing device, and a cleaning device disposed around these four photoconductors are respectively provided with respective photoconductors. Are arranged at the same position, and devices are shared for each device type.

【０００６】この図１１に示す実施の形態の場合、感光
体１１０〜１４０上に形成された各トナー画像は、転写
中間体１５１に転写された後転写中間体１５３に転写さ
れ、感光体１２０〜１３０上に形成された各トナー画像
は転写中間体１５２に転写された後転写中間体１５３に
転写され、中間転写体１５３に転写されたトナー画像が
搬送されてきた用紙Ｐ上に一括して転写される。用紙Ｐ
上に転写されたトナー画像は、図示しない定着装置によ
り用紙上に定着される。転写中間体１５１、１５２、１
５３は、ドラム型であって剛体からなるため、トナー画
像どうしの位置ずれは生じにくい。In the case of the embodiment shown in FIG. 11, each toner image formed on the photoconductors 110 to 140 is transferred to the transfer intermediate body 153 after being transferred to the transfer intermediate body 151, and is transferred to the photoconductors 120 to 140. Each toner image formed on 130 is transferred to transfer intermediate body 152 and then transferred to transfer intermediate body 153, and the toner image transferred to intermediate transfer body 153 is collectively transferred onto conveyed paper P. Is done. Paper P
The transferred toner image is fixed on a sheet by a fixing device (not shown). Transfer intermediates 151, 152, 1
53 is a drum type and is made of a rigid body, so that it is unlikely that a positional shift between toner images occurs.

【０００７】[0007]

【発明が解決しようとする課題】しかしながら、上記従
来技術の場合には、次のような問題点を有している。す
なわち、上記特開平１０−７８６８６号公報に開示され
た画像形成装置においては、図１１に示すように、感光
体１１０〜１４０上に残留したトナーを除去するため、
当該感光体１１０〜１４０の表面から残留トナーを除去
するクリーニング装置を使用している。このクリーニン
グ装置は、感光体の表面にクリーニングブレードを圧接
し、当該クリーニングブレードによって感光体表面に残
留したトナーを除去するように構成されている。However, the prior art described above has the following problems. That is, in the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. H10-78686, as shown in FIG. 11, the toner remaining on the photoconductors 110 to 140 is removed.
A cleaning device that removes residual toner from the surfaces of the photoconductors 110 to 140 is used. This cleaning device is configured so that a cleaning blade is pressed against the surface of the photoconductor and the toner remaining on the surface of the photoconductor is removed by the cleaning blade.

【０００８】しかし、感光体の表面にクリーニングブレ
ードを圧接し、当該クリーニングブレードによって感光
体表面に残留したトナーを除去するように構成した場合
には、感光体表面の感光層がクリーニングブレードによ
って磨耗され、感光体の寿命が短くなるという問題点を
有している。However, when the cleaning blade is pressed against the surface of the photoreceptor to remove toner remaining on the surface of the photoreceptor, the photosensitive layer on the surface of the photoreceptor is worn by the cleaning blade. In addition, there is a problem that the life of the photosensitive member is shortened.

【０００９】そこで、感光体の寿命を延ばすために、感
光体からクリーニング装置を取り外したタイプの所謂”
クリーナーレス”の画像形成装置が提案されている。Therefore, in order to extend the life of the photosensitive member, a so-called "type" in which a cleaning device is removed from the photosensitive member.
A "cleanerless" image forming apparatus has been proposed.

【００１０】しかしながら、上記特開平１０−７８６８
６号公報に開示された画像形成装置において、感光体の
寿命を延ばすために、感光体からクリーニング装置を取
り外すと、次のような問題点が生じる。However, Japanese Patent Application Laid-Open No.
In the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 6-106, if the cleaning device is removed from the photoconductor in order to extend the life of the photoconductor, the following problems occur.

【００１１】すなわち、上記特開平１０−７８６８６号
公報に開示された画像形成装置では、中間転写ユニット
を構成する転写中間体上に形成された、例えばイエロ
ー、マゼンタの二色のトナー像は、転写中間体との接触
部で静電的に転写中間体上に転写される。さらに、中間
転写ユニットを構成する転写中間体上に形成された、例
えばシアン、ブラックの二色のトナー像は、転写中間体
との接触部で静電的に転写中間体上に転写される。この
とき、転写中間体と転写中間体は、それぞれの表面速度
が、等速度で回転するように構成されている。That is, in the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 10-78686, for example, a two-color toner image of yellow and magenta formed on a transfer intermediate constituting an intermediate transfer unit is transferred. It is electrostatically transferred onto the transfer intermediate at a contact portion with the intermediate. Further, the toner images of two colors, for example, cyan and black, formed on the transfer intermediate constituting the intermediate transfer unit, are electrostatically transferred to the transfer intermediate at a contact portion with the transfer intermediate. At this time, the transfer intermediate and the transfer intermediate are configured so that their respective surface speeds rotate at a constant speed.

【００１２】このとき、転写中間体と転写中間体との間
の転写電界を最適化した場合でも、トナー像を形成する
トナー粒子は、その帯電分布が経時変化等によって当初
のものからブロードに広がったり、一部逆極性に帯電し
たトナーが生じ、又、転写中間体表面との間に静電気力
以外にファンデルワールス力等の分子間力が作用し、転
写効率が不十分で転写残りが発生してしまう場合があ
る。すると、転写中間体と転写中間体の転写部で発生し
た転写残りは、転写中間体が一周した後に、再度転写中
間体との転写部を通過することになり、この時に転写中
間体側に転写され、最終的にこの転写残りは、用紙上に
転写されてしまい、所謂”転写ゴースト”としてプリン
トアウトされてしまうという問題点が発生する。この問
題点は、転写中間体でも同様に発生する。At this time, even when the transfer electric field between the transfer intermediates is optimized, the toner particles forming the toner image have their charge distribution spread from the initial one to the broad one due to a change with time or the like. Or partially charged toner with reverse polarity, and intermolecular force such as van der Waals force acts on the surface of the transfer intermediate in addition to electrostatic force, resulting in insufficient transfer efficiency and transfer residue In some cases. Then, the transfer residue generated in the transfer intermediate and the transfer portion of the transfer intermediate passes through the transfer portion with the transfer intermediate again after the transfer intermediate makes one round, and is transferred to the transfer intermediate side at this time. Finally, there arises a problem that the transfer residue is transferred onto a sheet of paper and printed out as a so-called "transfer ghost". This problem also occurs in the transfer intermediate.

【００１３】また、かかる”転写ゴースト”を防止する
ため、転写中間体にクリーニング装置（図示せず）を設
けた場合であっても、各色のトナー像の転写効率が不十
分で、しかも各色のトナー像毎にバラツキがあると、各
色のトナー像の転写効率が不十分であることによる混色
や、濃度バラツキや濃度ムラを生じ、カラー画像の発色
性が変化し、画質が低下するという問題点を生じる。同
時に、転写中間体に設けたクリーニング装置に未転写ト
ナーが多量に滞留することになり、クリーニング装置の
トナー漏れ対策や、クリーニングされたトナーの回収機
構などが必要となり、コストアップとなるという問題点
をも生じる。Further, in order to prevent such "transfer ghost", even when a cleaning device (not shown) is provided in the transfer intermediate, the transfer efficiency of the toner image of each color is insufficient, and furthermore, the transfer efficiency of each color is insufficient. If there is variation in each toner image, color transfer due to insufficient transfer efficiency of each color toner image, density variation and density unevenness occur, and the color developing property of the color image changes, and the image quality deteriorates. Is generated. At the same time, a large amount of untransferred toner stagnates in the cleaning device provided in the transfer intermediate body, which requires a countermeasure for toner leakage of the cleaning device and a mechanism for collecting the cleaned toner, resulting in an increase in cost. Also occurs.

【００１４】このように、上記特開平１０−７８６８６
号公報に開示されている画像形成装置においては、感光
体から転写中間体への転写工程、転写中間体から転写中
間体への転写工程、転写中間体から用紙への転写工程と
いうように、三回の転写工程が必要となるのと同時に、
感光体の寿命を延ばすためにクリーニング装置をなくす
と、接触方式の転写中間体の汚れ防止や、混色防止等の
ために、特に、高い転写効率が求められ、転写効率の大
幅な向上が重要な技術的課題となっている。As described above, Japanese Patent Application Laid-Open No. H10-78686 describes
In the image forming apparatus disclosed in Japanese Patent Application Laid-Open Publication No. H11-163, a transfer step from a photoconductor to a transfer intermediate, a transfer step from a transfer intermediate to a transfer intermediate, and a transfer step from a transfer intermediate to a sheet are performed in three steps. Times transfer process is required,
If the cleaning device is eliminated to extend the life of the photoconductor, a high transfer efficiency is particularly required to prevent contamination of the contact-type transfer intermediate and prevent color mixing, and it is important to greatly improve the transfer efficiency. It is a technical issue.

【００１５】そこで、この発明は、上記従来技術の問題
点を解決するためになされたものであり、その目的とす
るところは、駆動系の簡易化や装置の小型化を可能と
し、又感光体等の像担持体の長寿命化を可能とした場合
であっても、転写効率を大幅に向上させることによ
り、”転写ゴースト”や濃度変動などの発生を確実に防
止し、高画質のカラー画像を形成することが可能な画像
形成装置を提供することにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to make it possible to simplify a drive system and downsize an apparatus. Even if it is possible to extend the life of the image carrier, such as by using a high-quality color image, the transfer efficiency is greatly improved to prevent "transfer ghosts" and density fluctuations. An object of the present invention is to provide an image forming apparatus capable of forming an image.

【００１６】[0016]

【課題を解決するための手段】上記の課題を解決するた
め、請求項１に記載された発明は、互いに色の異なった
トナー像が形成される複数の像担持体と、これら複数の
像担持体のうちの少なくとも一部からトナー像が転写さ
れる一次中間転写体と、少なくとも当該一次中間転写体
からトナー像が転写される二次中間転写体とを備え、前
記複数の像担持体上に形成された色の異なったトナー像
のうち少なくとも一部のトナー像は、一次中間転写体を
介して二次中間転写体上に多重に転写することにより、
カラーの画像を形成する画像形成装置において、前記像
担持体からトナー像が転写される一次中間転写体の抵抗
値より、当該一次中間転写体からトナー像が転写される
二次中間転写体の抵抗値を高く設定するように構成され
ている。In order to solve the above-mentioned problems, the invention described in claim 1 comprises a plurality of image carriers on which toner images of different colors are formed, and a plurality of these image carriers. A primary intermediate transfer member to which a toner image is transferred from at least a part of the body, and a secondary intermediate transfer member to which a toner image is transferred from at least the primary intermediate transfer member; At least a part of the formed toner images of different colors is transferred in a multiplex manner onto the secondary intermediate transfer body via the primary intermediate transfer body,
In an image forming apparatus for forming a color image, a resistance value of a secondary intermediate transfer body on which a toner image is transferred from the primary intermediate transfer body is determined based on a resistance value of a primary intermediate transfer body on which a toner image is transferred from the image carrier. It is configured to set a high value.

【００１７】上記複数の像担持体としては、例えば、シ
アン（Ｃ）、マゼンタ（Ｍ）、イエロー（Ｙ）、及びブ
ラック（Ｋ）の各色のトナー像を形成するものが用いら
れるが、これらの色の順番や種類は、他のものであって
も勿論よい。As the plurality of image carriers, for example, those which form toner images of respective colors of cyan (C), magenta (M), yellow (Y), and black (K) are used. The order and type of the colors may be other.

【００１８】また、上記複数の像担持体としては、例え
ば、シアン（Ｃ）、マゼンタ（Ｍ）、イエロー（Ｙ）、
及びブラック（Ｋ）の各色のトナー像を形成する４つの
感光体ドラムが用いられるが、他の静電潜像を形成する
静電潜像担持体等からなるものであっても良い。The plurality of image carriers include, for example, cyan (C), magenta (M), yellow (Y),
Although four photosensitive drums for forming toner images of respective colors of black and black (K) are used, the photosensitive drum may be formed of an electrostatic latent image carrier for forming another electrostatic latent image.

【００１９】さらに、上記一次中間転写体は、例えば、
２つ設けられるが、これに限定されるものではなく、１
つであっても良いし、３つ以上設けても良い。Further, the primary intermediate transfer member is, for example,
Two are provided, but are not limited to this.
Or three or more.

【００２０】また更に、上記二次中間転写体は、通常、
１つのみ設けられるが、当該二次中間転写体を２つ以上
設け、これら複数の二次中間転写体上に転写されたトナ
ー像を、当該複数の二次中間転写体に接触する三次中間
転写体に転写するように構成しても良い。Further, the secondary intermediate transfer member is usually
Although only one is provided, two or more secondary intermediate transfer bodies are provided, and the toner images transferred onto the plurality of secondary intermediate transfer bodies are transferred to the tertiary intermediate transfer contacting the plurality of secondary intermediate transfer bodies. You may comprise so that it may transfer to a body.

【００２１】また、請求項２に記載された発明は、互い
に色の異なったトナー像が形成される複数の像担持体
と、これら複数の像担持体からトナー像が転写される複
数の一次中間転写体と、これら複数の一次中間転写体か
らトナー像が多重に転写される二次中間転写体とを備
え、前記複数の像担持体上に形成された色の異なったト
ナー像を、複数の一次中間転写体を介して二次中間転写
体上に多重に転写することにより、カラーの画像を形成
する画像形成装置において、前記像担持体からトナー像
が転写される一次中間転写体の抵抗値より、当該一次中
間転写体からトナー像が転写される二次中間転写体の抵
抗値を高く設定するように構成される。According to a second aspect of the present invention, there are provided a plurality of image carriers on which toner images of different colors are formed, and a plurality of primary intermediate members onto which toner images are transferred from the plurality of image carriers. A transfer member, and a secondary intermediate transfer member in which toner images are transferred from the plurality of primary intermediate transfer members in a multiplex manner, and a plurality of toner images of different colors formed on the plurality of image carriers are transferred to a plurality of In an image forming apparatus that forms a color image by transferring multiple images onto a secondary intermediate transfer member via a primary intermediate transfer member, a resistance value of a primary intermediate transfer member onto which a toner image is transferred from the image bearing member Thus, the resistance value of the secondary intermediate transfer member onto which the toner image is transferred from the primary intermediate transfer member is set to be high.

【００２２】さらに、請求項３に記載された発明は、互
いに色の異なったトナー像が形成される複数の像担持体
と、これら複数の像担持体のうちの少なくとも一部から
トナー像が転写される一次中間転写体と、少なくとも当
該一次中間転写体からトナー像が転写される二次中間転
写体とを備え、前記複数の像担持体上に形成された色の
異なったトナー像のうち少なくとも一部のトナー像は、
一次中間転写体を介して二次中間転写体上に多重に転写
することにより、カラーの画像を形成する画像形成装置
において、前記像担持体からトナー像が転写される一次
中間転写体の抵抗値より、当該一次中間転写体からトナ
ー像が転写される二次中間転写体の抵抗値を高く設定す
るとともに、前記一次中間転写体と二次中間転写体の接
触転写部で、一次中間転写体の表面速度と二次中間転写
体の表面速度に差を設けるように構成される。Further, according to the present invention, a plurality of image carriers on which toner images of different colors are formed, and a toner image is transferred from at least a part of the plurality of image carriers. A primary intermediate transfer member, and a secondary intermediate transfer member on which a toner image is transferred from at least the primary intermediate transfer member, and at least one of the toner images of different colors formed on the plurality of image carriers. Some toner images are
In an image forming apparatus that forms a color image by transferring multiple images onto a secondary intermediate transfer member via a primary intermediate transfer member, a resistance value of a primary intermediate transfer member onto which a toner image is transferred from the image bearing member Accordingly, the resistance value of the secondary intermediate transfer body on which the toner image is transferred from the primary intermediate transfer body is set to be high, and the contact transfer section between the primary intermediate transfer body and the secondary intermediate transfer body, It is configured to provide a difference between the surface speed and the surface speed of the secondary intermediate transfer member.

【００２３】また更に、請求項４に記載された発明は、
互いに色の異なったトナー像が形成される複数の像担持
体と、これら複数の像担持体のうちの少なくとも一部か
らトナー像が転写される一次中間転写体と、少なくとも
当該一次中間転写体からトナー像が転写される二次中間
転写体とを備え、前記複数の像担持体上に形成された色
の異なったトナー像のうち少なくとも一部のトナー像
は、一次中間転写体を介して二次中間転写体上に多重に
転写することにより、カラーの画像を形成する画像形成
装置において、前記像担持体よりも一次中間転写体の表
面速度を速く設定し、二次中間転写体の表面速度を一次
中間転写体の表面速度よりも遅く設定するように構成さ
れる。Still further, the invention described in claim 4 is:
A plurality of image carriers on which toner images of different colors are formed, a primary intermediate transfer body on which a toner image is transferred from at least a part of the plurality of image carriers, and at least a primary intermediate transfer body And a secondary intermediate transfer member onto which a toner image is transferred. At least a part of the toner images of different colors formed on the plurality of image carriers is transferred to the secondary intermediate transfer member via the primary intermediate transfer member. In an image forming apparatus that forms a color image by performing multiple transfers on the secondary intermediate transfer member, the surface speed of the primary intermediate transfer member is set higher than that of the image carrier, and the surface speed of the secondary intermediate transfer member is set. Is set to be lower than the surface speed of the primary intermediate transfer member.

【００２４】さらに、請求項５に記載された発明は、互
いに色の異なったトナー像が形成される複数の像担持体
と、これら複数の像担持体のうちの少なくとも一部から
トナー像が転写される一次中間転写体と、少なくとも当
該一次中間転写体からトナー像が転写される二次中間転
写体とを備え、前記複数の像担持体上に形成された色の
異なったトナー像のうち少なくとも一部のトナー像は、
一次中間転写体を介して二次中間転写体上に多重に転写
することにより、カラーの画像を形成する画像形成装置
において、前記像担持体よりも一次中間転写体の表面速
度を遅く設定し、二次中間転写体の表面速度を一次中間
転写体の表面速度よりも速く設定するように構成され
る。Further, according to the present invention, a plurality of image carriers on which toner images of different colors are formed, and a toner image is transferred from at least a part of the plurality of image carriers. A primary intermediate transfer member, and a secondary intermediate transfer member on which a toner image is transferred from at least the primary intermediate transfer member, and at least one of the toner images of different colors formed on the plurality of image carriers. Some toner images are
In the image forming apparatus that forms a color image by transferring multiple images onto the secondary intermediate transfer body through the primary intermediate transfer body, the surface speed of the primary intermediate transfer body is set to be lower than that of the image carrier, The surface speed of the secondary intermediate transfer member is set to be higher than the surface speed of the primary intermediate transfer member.

【００２５】[0025]

【作用】請求項１に記載された発明においては、像担持
体からトナー像が転写される一次中間転写体の抵抗値よ
り、当該一次中間転写体からトナー像が転写される二次
中間転写体の抵抗値を高く設定するように構成したの
で、像担持体から一次中間転写体上に転写されたトナー
像を、二次中間転写体に転写する際に、相対的に抵抗値
が高く設定された二次中間転写体から一次中間転写体に
対する電荷の注入が抑制され、逆極性トナーの発生を防
止し、リトランスファーによる転写残り量を極力少なく
することができ、駆動系の簡易化や装置の小型化を可能
とし、又感光体等の像担持体の長寿命化を可能とした場
合であっても、転写効率を大幅に向上させることによ
り、”転写ゴースト”や濃度変動などの発生を確実に防
止し、高画質のカラー画像を形成することが可能とな
る。According to the first aspect of the present invention, the secondary intermediate transfer member onto which the toner image is transferred from the primary intermediate transfer member is determined based on the resistance value of the primary intermediate transfer member onto which the toner image is transferred from the image carrier. The resistance value is set to be relatively high when the toner image transferred from the image carrier onto the primary intermediate transfer member is transferred to the secondary intermediate transfer member. Injection of electric charge from the secondary intermediate transfer member to the primary intermediate transfer member is suppressed, generation of reverse polarity toner can be prevented, the transfer remaining amount by retransfer can be reduced as much as possible, and the drive system can be simplified and the device can be simplified. Even if it is possible to reduce the size and extend the life of the image carrier such as the photoconductor, the transfer efficiency is greatly improved to ensure the occurrence of "transfer ghost" and density fluctuation. High quality color It is possible to form an image.

【００２６】また、請求項２に記載された発明は、像担
持体からトナー像が転写される一次中間転写体の抵抗値
より、当該一次中間転写体からトナー像が転写される二
次中間転写体の抵抗値を高く設定するように構成したの
で、請求項１に記載された発明と同様の作用を奏する。According to a second aspect of the present invention, there is provided a secondary intermediate transfer device for transferring a toner image from a primary intermediate transfer member based on a resistance value of the primary intermediate transfer member on which a toner image is transferred from an image carrier. Since the configuration is such that the resistance value of the body is set to be high, the same effect as the invention described in claim 1 is exerted.

【００２７】さらに、請求項３に記載された発明は、像
担持体からトナー像が転写される一次中間転写体の抵抗
値より、当該一次中間転写体からトナー像が転写される
二次中間転写体の抵抗値を高く設定するとともに、前記
一次中間転写体と二次中間転写体の接触転写部で、一次
中間転写体の表面速度と二次中間転写体の表面速度に差
を設けるように構成したので、請求項１に記載された発
明に加えて、一次中間転写体と二次中間転写体の接触転
写部で、一次中間転写体の表面速度と二次中間転写体の
表面速度に差を設けることにより、一次中間転写体から
二次中間転写体へのトナー像の転写効率を一層向上させ
ることができ、駆動系の簡易化や装置の小型化を可能と
し、又感光体等の像担持体の長寿命化を可能とした場合
であっても、転写効率をより一層大幅に向上させること
により、”転写ゴースト”や濃度変動などの発生を確実
に防止し、高画質のカラー画像を形成することが可能と
なる。Further, according to the third aspect of the present invention, the secondary intermediate transfer in which the toner image is transferred from the primary intermediate transfer member is determined based on the resistance value of the primary intermediate transfer member in which the toner image is transferred from the image carrier. And the contact transfer section between the primary intermediate transfer member and the secondary intermediate transfer member is configured to provide a difference between the surface speed of the primary intermediate transfer member and the surface speed of the secondary intermediate transfer member. Therefore, in addition to the invention described in claim 1, the difference between the surface speed of the primary intermediate transfer member and the surface speed of the secondary intermediate transfer member in the contact transfer portion between the primary intermediate transfer member and the secondary intermediate transfer member. By providing this, the transfer efficiency of the toner image from the primary intermediate transfer member to the secondary intermediate transfer member can be further improved, the drive system can be simplified, the apparatus can be downsized, and the image bearing member such as a photoreceptor can be supported. Even if it is possible to extend the life of the body, transfer A more possible to further significantly improve the rate, and reliably prevent the occurrence of "transfer ghosts" and density variations, it is possible to form a color image of high quality.

【００２８】また更に、請求項４に記載された発明は、
像担持体よりも一次中間転写体の表面速度を速く設定
し、二次中間転写体の表面速度を一次中間転写体の表面
速度よりも遅く設定するように構成したので、像担持体
と一次中間転写体の間、及び二次中間転写体と一次中間
転写体の間に、それぞれ表面速度の差を設定することに
より、請求項３に記載された発明と同様に、像担持体か
ら一次中間転写体、及び一次中間転写体から二次中間転
写体へのトナー像の転写効率を一層向上させることがで
きるのは勿論のこと、像担持体よりも一次中間転写体の
表面速度を速く設定して、トナー像がプロセス方向に拡
大されても、二次中間転写体の表面速度を一次中間転写
体の表面速度よりも遅く設定することにより、トナー像
がプロセス方向に縮小して、本来の倍率でトナー像を二
次中間転写体に多重に転写して、画像を形成することが
可能となる。Still further, the invention described in claim 4 is:
The surface speed of the primary intermediate transfer member is set higher than that of the image carrier, and the surface speed of the secondary intermediate transfer member is set lower than the surface speed of the primary intermediate transfer member. By setting a difference in surface speed between the transfer members and between the secondary intermediate transfer member and the primary intermediate transfer member, the primary intermediate transfer from the image bearing member is performed in the same manner as the invention described in claim 3. Body, and of course, it is possible to further improve the transfer efficiency of the toner image from the primary intermediate transfer member to the secondary intermediate transfer member by setting the surface speed of the primary intermediate transfer member higher than that of the image carrier. Even if the toner image is enlarged in the process direction, the toner image is reduced in the process direction by setting the surface speed of the secondary intermediate transfer member to be lower than the surface speed of the primary intermediate transfer member, and the original image is enlarged at the original magnification. Multiplex toner image on secondary intermediate transfer body Transfer to, images can be formed.

【００２９】さらに、請求項５に記載された発明は、像
担持体よりも一次中間転写体の表面速度を遅く設定し、
二次中間転写体の表面速度を一次中間転写体の表面速度
よりも速く設定するように構成したので、像担持体と一
次中間転写体の間、及び二次中間転写体と一次中間転写
体の間に、それぞれ表面速度の差を設定することによ
り、請求項３に記載された発明と同様に、像担持体から
一次中間転写体、及び一次中間転写体から二次中間転写
体へのトナー像の転写効率を一層向上させることができ
るのは勿論のこと、像担持体よりも一次中間転写体の表
面速度を遅く設定して、トナー像がプロセス方向に縮小
されても、二次中間転写体の表面速度を一次中間転写体
の表面速度よりも速く設定することにより、トナー像が
プロセス方向に拡大して、本来の倍率でトナー像を二次
中間転写体に多重に転写して、画像を形成することが可
能となる。Further, according to the present invention, the surface speed of the primary intermediate transfer member is set lower than that of the image carrier,
Since the surface speed of the secondary intermediate transfer member is set to be higher than the surface speed of the primary intermediate transfer member, the surface speed between the image bearing member and the primary intermediate transfer member, and between the secondary intermediate transfer member and the primary intermediate transfer member are set. In the same manner as in the invention described in claim 3, by setting a difference between the surface velocities between them, the toner image from the image bearing member to the primary intermediate transfer member and from the primary intermediate transfer member to the secondary intermediate transfer member Of course, the surface speed of the primary intermediate transfer member is set lower than that of the image carrier, so that even if the toner image is reduced in the process direction, the secondary intermediate transfer member can be further improved. By setting the surface speed of the toner image higher than the surface speed of the primary intermediate transfer member, the toner image is enlarged in the process direction, and the toner image is transferred to the secondary intermediate transfer member at the original magnification in multiples, and the image is formed. It can be formed.

【００３０】[0030]

【発明の実施の形態】以下、実施例に基づいて、この発
明の好適な実施の形態を図面を参照して具体的に説明す
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings based on examples.

【００３１】〔実施例１〕図１はこの発明の実施例１に
係るタンデム型フルカラー画像形成装置を示すものであ
る。Embodiment 1 FIG. 1 shows a tandem type full-color image forming apparatus according to Embodiment 1 of the present invention.

【００３２】この実施例１のフルカラー画像形成装置
は、図１に示すように、シアン（Ｃ）用、マゼンタ
（Ｍ）用、イエロー（Ｙ）用、及びブラック（Ｋ）用の
４つの感光体ドラム（像担持体）10, 20, 30, 40と、こ
れら感光体ドラム10, 20, 30, 40に接触する一次帯電用
の帯電ロール（接触型帯電装置）11, 21, 31, 41と、露
光装置12, 22, 32, 42と、現像装置13, 23, 33, 43と、
上記４つの感光体ドラム10,20, 30, 40のうちの２つの
感光体10, 20に接触する一方の一次中間転写ドラム（中
間転写体）51及び他の２つの感光体ドラム30, 40に接触
する他方の一次中間転写ドラム（中間転写体）52と、上
記一対の一次中間転写ドラム（中間転写体）51, 52に接
触する二次中間転写ドラム（中間転写体）53と、この二
次中間転写ドラム53に接触する最終転写ロール61と、搬
送ロール91と、定着装置70とを備えている。As shown in FIG. 1, the full-color image forming apparatus of the first embodiment includes four photosensitive members for cyan (C), magenta (M), yellow (Y), and black (K). Drums (image carriers) 10, 20, 30, 40; and charging rolls (contact-type charging devices) 11, 21, 31, 41 for primary charging that contact these photosensitive drums 10, 20, 30, 40; Exposure devices 12, 22, 32, 42 and developing devices 13, 23, 33, 43,
One of the primary intermediate transfer drums (intermediate transfer members) 51 and the other two photosensitive drums 30, 40, which are in contact with two of the four photosensitive drums 10, 20, 30, 40, The other primary intermediate transfer drum (intermediate transfer member) 52 that comes into contact, the secondary intermediate transfer drum (intermediate transfer member) 53 that contacts the pair of primary intermediate transfer drums (intermediate transfer members) 51 and 52, A final transfer roll 61 that comes into contact with the intermediate transfer drum 53, a transport roll 91, and a fixing device 70 are provided.

【００３３】また、この実施例１において、２つの感光
体ドラム10, 20で形成された各単色トナー像は、一次中
間転写ドラム51に転写された後に二次中間転写ドラム53
に転写され、また、２つの感光体ドラム30, 40で形成さ
れた各単色トナー像は、一次中間転写ドラム52に転写さ
れた後に二次中間転写ドラム53に転写され、この二次中
間転写ドラム53上で重ね合わされ、次いで搬送ロール91
により上記二次中間転写ドラム53に接触する最終転写ロ
ール61との間に搬送されてきた記録用紙（記録シート）
Ｐ上に一括して転写され、この記録用紙Ｐ上に転写され
たトナー像は定着装置70により定着される。In the first embodiment, each single-color toner image formed on the two photosensitive drums 10 and 20 is transferred to the primary intermediate transfer drum 51, and then transferred to the secondary intermediate transfer drum 53.
The single-color toner images formed on the two photosensitive drums 30 and 40 are transferred to a primary intermediate transfer drum 52 and then to a secondary intermediate transfer drum 53. 53 and then transport roll 91
The recording paper (recording sheet) conveyed between the second intermediate transfer drum 53 and the final transfer roll 61 that contacts the secondary intermediate transfer drum 53
The toner image transferred collectively onto the recording paper P and transferred onto the recording paper P is fixed by the fixing device 70.

【００３４】そして、この実施例１において、上記感光
体ドラム10, 20, 30, 40の表面は、図２に示すように、
接触型帯電装置としての帯電ロール11, 21, 31, 41に、
−１０００Ｖ程度の電圧を印加することによって、−５
００Ｖ程度に帯電され、また、露光装置12, 22, 32, 42
で静電潜像が書き込まれた際に、その画像露光部の表面
電位は−１００Ｖ以下程度にまで除電される。In the first embodiment, the surfaces of the photosensitive drums 10, 20, 30, and 40 are, as shown in FIG.
The charging rolls 11, 21, 31, 41 as contact-type charging devices
By applying a voltage of about -1000 V, -5
It is charged to about 00V, and the exposure devices 12, 22, 32, 42
When the electrostatic latent image is written, the surface potential of the image exposed portion is eliminated to about -100 V or less.

【００３５】また、この実施例１において、現像装置1
3, 23, 33, 43は、現像ロール131 、現像剤量規制部材1
32 、現像剤搬送部材133 、及び現像剤を搬送し、ま
た、攪拌するオーガー134 を備えた磁気ブラシ接触型二
成分現像方式の現像装置である。上記現像剤量規制部材
132 によって規制されて現像部に搬送される現像剤量は
約３０〜４０ｇ／ｍ2 であり、この時に現像ロール131
上に存在するトナーの帯電量は概ね−２０〜−３０μＣ
／ｇ程度である。この現像装置13, 23, 33, 43には、Ａ
Ｃ＋ＤＣの現像電圧を印加して現像が実施されるが、こ
の現像電圧はＡＣが４ｋＨｚ、１．６ｋＶppで、ＤＣが
−２３０Ｖ程度である。In the first embodiment, the developing device 1
3, 23, 33 and 43 are a developing roll 131 and a developer amount regulating member 1
32, a developer transporting member 133, and a magnetic brush contact type two-component developing type developing device including an auger 134 for transporting and agitating the developer. The developer amount regulating member
The amount of the developer conveyed to the developing unit while being regulated by 132 is about 30 to 40 g / m 2.
The charge amount of the toner existing on the surface is approximately −20 to −30 μC.
/ G. The developing devices 13, 23, 33, 43 have A
The development is carried out by applying a C + DC development voltage. The development voltage is 4 kHz for AC, 1.6 kVpp, and about -230 V for DC.

【００３６】更に、この実施例１で用いる一次中間転写
ドラム51, 52は、芯金としての金属パイプ51a,52ａの上
にシリコンゴム層51b,52b を設け、更にその上にフッ素
系樹脂からなる高離型層51c,52c をコーティングし焼成
することによって形成されており、その抵抗値について
は、通常１０6 〜１０9 Ωの範囲のものを使用できる
が、ここでは１０8 Ω程度に設定されている。なお、上
記一次中間転写ドラム51, 52の抵抗値は、例えば、フッ
素系樹脂からなる高離型層51c,52c の焼成温度を制御す
ることによって調整される。そして、上記感光体ドラム
10, 20, 30, 40からこの一次中間転写ドラム51, 52にト
ナー像を転写するのに必要な表面電位は、通常＋２５０
〜５００Ｖ程度の範囲であり、トナーの帯電状態、雰囲
気温度、湿度等により最適値を設定することになるが、
ここでは図２に示すように表面電位が＋３００Ｖ程度に
設定されている。Further, the primary intermediate transfer drums 51 and 52 used in the first embodiment are provided with silicon rubber layers 51b and 52b on metal pipes 51a and 52a as metal cores, and further made of a fluorine-based resin thereon. It is formed by coating and firing the high release layers 51c and 52c, and the resistance value thereof is usually in the range of 10 6 to 10 9 Ω, but here it is set to about 10 8 Ω. ing. The resistance values of the primary intermediate transfer drums 51 and 52 are adjusted by controlling the firing temperature of the high release layers 51c and 52c made of a fluororesin, for example. And the photoconductor drum
The surface potential required to transfer a toner image from 10, 20, 30, 40 to these primary intermediate transfer drums 51, 52 is usually +250
It is in the range of about 500 V, and the optimum value is set according to the charged state of the toner, the ambient temperature, the humidity, and the like.
Here, the surface potential is set at about +300 V as shown in FIG.

【００３７】また、この実施例１で用いる二次中間転写
ドラム53も、上記一次中間転写ドラム51, 52と同様に、
金属パイプの上にシリコンゴム層を設け、更にその上に
高離型層をコーティングして形成されており、その抵抗
値については、通常１０8 〜１０12Ωの範囲のものを使
用できるが、ここでは１０9 Ω程度とされている。そし
て、上記一次中間転写ドラム51, 52からこの二次中間転
写ドラム53にトナー像を転写するのに必要な表面電位
は、通常＋６００〜１２００Ｖ程度の範囲であり、トナ
ーの帯電状態、雰囲気温度、湿度等により最適値を設定
することになるが、ここでは図２に示すように表面電位
が＋８００Ｖ程度に設定され、電位差が＋５００Ｖ程度
になっている。この一次中間転写ドラム51, 52と二次中
間転写ドラム53との電位差は、ある程度高い方が二次転
写効率が向上するが、＋５００Ｖを超えると、放電現象
が生じやすくなるため、電位差＋５００Ｖ程度が条件に
よっては限界となるが、これに限定されるものではな
い。The secondary intermediate transfer drum 53 used in the first embodiment is also similar to the primary intermediate transfer drums 51 and 52 described above.
A silicon rubber layer is provided on a metal pipe, and a high release layer is further coated thereon. The resistance value of the silicon rubber layer is usually in the range of 10 8 to 10 12 Ω. Here, it is set to about 10 9 Ω. The surface potential required for transferring the toner image from the primary intermediate transfer drums 51 and 52 to the secondary intermediate transfer drum 53 is usually in the range of about +600 to 1200 V, and the charged state of the toner, the ambient temperature, The optimum value is set according to the humidity and the like. Here, as shown in FIG. 2, the surface potential is set to about +800 V, and the potential difference is about +500 V. The potential difference between the primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 increases the secondary transfer efficiency if the potential is higher to some extent. However, if the potential difference exceeds +500 V, a discharge phenomenon is likely to occur. It may be limited depending on conditions, but is not limited to this.

【００３８】更に、この実施例１において、最終転写ロ
ール61は、金属パイプの上にウレタンゴム層を設け、更
にその上にコーティングが施されており、その抵抗値に
ついては、通常１０6 〜１０9 Ωの範囲のものを使用で
きるが、ここでは１０8 Ω程度とされている。そして、
上記二次中間転写ドラム53から記録用紙Ｐ上にトナー像
を転写するのに、この最終転写ロール61に印加する転写
電圧は、通常＋１２００〜５０００Ｖ程度の範囲であ
り、雰囲気温度、湿度、用紙Ｐの種類（抵抗値等）等に
より最適値を設定することになるが、ここでは定電流方
式を採用して常温常湿環境下で約＋６μＡを印加し、ほ
ぼ適正な転写電圧＋１６００〜２０００Ｖ程度を得てい
る。Further, in the first embodiment, the final transfer roll 61 is provided with a urethane rubber layer on a metal pipe and further coated thereon, and the resistance value thereof is usually 10 6 to 10. Although a range of 9 Ω can be used, it is set to about 10 8 Ω here. And
The transfer voltage applied to the final transfer roll 61 for transferring the toner image from the secondary intermediate transfer drum 53 onto the recording paper P is generally in the range of about +1200 to 5000 V. The optimum value is set according to the type (resistance value, etc.) of the device, but here, a constant current method is adopted, and about +6 μA is applied in a normal temperature and normal humidity environment, and an approximately appropriate transfer voltage of about 1600 to 2000 V is applied. It has gained.

【００３９】さらに、この実施例１では、一次中間転写
体と二次中間転写体の接触転写部で、一次中間転写体の
表面速度と二次中間転写体の表面速度に差を設けるよう
に構成されている。Further, in the first embodiment, a difference is made between the surface speed of the primary intermediate transfer member and the surface speed of the secondary intermediate transfer member in the contact transfer portion between the primary intermediate transfer member and the secondary intermediate transfer member. Have been.

【００４０】すなわち、この実施例１では、一次中間転
写ドラム51, 52の表面速度を、二次中間転写ドラム53の
表面速度より速く設定するか、又は遅く設定することに
よって、一次中間転写ドラム51, 52の表面速度と二次中
間転写ドラム53の表面速度に差を設けるように構成され
ている。That is, in the first embodiment, the surface speeds of the primary intermediate transfer drums 51 and 52 are set to be higher or lower than the surface speed of the secondary intermediate transfer drum 53, so that the primary intermediate transfer drum 51 , 52 and the surface speed of the secondary intermediate transfer drum 53.

【００４１】なお、この実施例１のフルカラー画像形成
装置では、上記最終転写ロール61に対して、クリーニン
グブレード72を有するブレードクリーニング装置71が付
設され、また、上記各帯電ロール11, 21, 31, 41、各一
次中間転写ドラム51, 52、二次中間転写ドラム53、及び
最終転写ロール61には、クリーニング工程において、所
定の電圧を印加して各帯電ロール11, 21, 31, 41、各感
光体ドラム10, 20, 30, 40、各一次中間転写ドラム51,
52、二次中間転写ドラム53、及び最終転写ロール61の間
に所定の電位勾配を形成せしめ、一次中間転写ドラム5
1, 52や二次中間転写ドラム53の表面等のクリーニング
を行うようになっている。In the full-color image forming apparatus according to the first embodiment, a blade cleaning device 71 having a cleaning blade 72 is attached to the final transfer roll 61, and the charging rolls 11, 21, 31, and 31 are also provided. 41, a predetermined voltage is applied to each of the primary intermediate transfer drums 51, 52, the secondary intermediate transfer drum 53, and the final transfer roll 61 in the cleaning step to charge the respective charging rolls 11, 21, 31, 41, Body drums 10, 20, 30, 40, each primary intermediate transfer drum 51,
A predetermined potential gradient is formed between the secondary intermediate transfer drum 53 and the final transfer roll 61, and the primary intermediate transfer drum 5
Cleaning of the surfaces of the first and second 52 and the secondary intermediate transfer drum 53 is performed.

【００４２】以上の構成において、この実施例１に係る
フルカラー画像形成装置においては、次に示すようにし
て、駆動系の簡易化や装置の小型化を可能とし、又感光
体等の像担持体の長寿命化を可能とした場合であって
も、転写効率を大幅に向上させることにより、”転写ゴ
ースト”や濃度変動などの発生を確実に防止し、高画質
のカラー画像を形成することが可能となっている。With the above arrangement, in the full-color image forming apparatus according to the first embodiment, the driving system can be simplified and the apparatus can be reduced in size as described below. Even if it is possible to extend the life of the printer, the transfer efficiency can be greatly improved to prevent "transfer ghosts" and density fluctuations, thereby forming high-quality color images. It is possible.

【００４３】すなわち、この実施例１に係るフルカラー
画像形成装置においては、図１に示すように、感光体ド
ラム10, 20, 30, 40の表面が、接触型帯電装置としての
帯電ロール11, 21, 31, 41に、−１０００Ｖ程度の電圧
を印加することによって、−５００Ｖ程度に帯電された
後、露光装置12, 22, 32, 42によって画像部が露光され
ることで静電潜像が書き込まれ、その画像露光部の表面
電位は−１００Ｖ以下程度にまで除電される。その際、
上記感光体ドラム10, 20, 30, 40の表面には、それぞれ
露光装置12, 22, 32, 42によってシアン、マゼンタ、イ
エロー、黒の各色に対応した静電潜像が順次形成され
る。That is, in the full-color image forming apparatus according to the first embodiment, as shown in FIG. 1, the surfaces of the photosensitive drums 10, 20, 30, and 40 are charged with the charging rolls 11, 21 as contact-type charging devices. , 31, 41 are charged to about -500 V by applying a voltage of about -1000 V, and then the image portions are exposed by the exposure devices 12, 22, 32, 42 to write an electrostatic latent image. Then, the surface potential of the image exposed portion is discharged to about -100 V or less. that time,
On the surfaces of the photosensitive drums 10, 20, 30, and 40, electrostatic latent images corresponding to cyan, magenta, yellow, and black are sequentially formed by the exposure devices 12, 22, 32, and 42, respectively.

【００４４】上記感光体ドラム10, 20, 30, 40の表面に
形成された静電潜像は、現像装置13, 23, 33, 43によっ
て現像され、当該感光体ドラム10, 20, 30, 40の表面に
は、シアン、マゼンタ、イエロー、黒の各色のトナー像
が順次形成される。感光体ドラム10, 20の表面に形成さ
れたシアン及びマゼンタ色のトナー像は、一次中間転写
ドラム51上に一次転写され、感光体ドラム30, 40の表面
に形成されたイエロー及び黒色のトナー像は、一次中間
転写ドラム51, 52上に一次転写される。The electrostatic latent images formed on the surfaces of the photosensitive drums 10, 20, 30, and 40 are developed by developing devices 13, 23, 33, and 43, and the photosensitive drums 10, 20, 30, and 40 are developed. , Toner images of respective colors of cyan, magenta, yellow, and black are sequentially formed. The cyan and magenta toner images formed on the surfaces of the photoconductor drums 10 and 20 are primarily transferred onto the primary intermediate transfer drum 51, and the yellow and black toner images formed on the surfaces of the photoconductor drums 30 and 40 are formed. Is primarily transferred onto the primary intermediate transfer drums 51 and 52.

【００４５】その際、一次中間転写ドラム51, 52の芯金
には、感光体ドラム10, 20, 30, 40上に形成されたシア
ン及びマゼンタ色、並びにイエロー及び黒色の各トナー
像を、当該一次中間転写ドラム51, 52上に静電的に転写
するために、一次転写電圧が印加される。この時、一次
中間転写ドラム51, 52の抵抗値（２２℃／５５％ＲＨ環
境 １００Ｖ印加時；以下、特に明示しない場合の抵抗
値は、この測定条件で測定したものとする。）が、１×
１０8.5 Ω程度より高いと、一次転写を行うために感光
体ドラムと一次中間転写ドラムとのニップ部に注入する
電荷を維持するために、一次中間転写ドラム51, 52に印
加する一次転写電圧を高く設定しなければならない。し
かし、一次中間転写ドラム51, 52に高い一次転写電圧を
印加すると、一次中間転写ドラム51, 52上に転写された
トナー像の転写ブラー（転写像のまわりにトナーが飛び
散る現象）が悪化する。そこで、一次中間転写ドラム5
1,52の抵抗値を１×１０6 Ω程度から１×１０8 Ω程度
の抵抗値に設定することで、一次転写電圧を低く設定
し、転写ブラーを抑制することが可能となる。At this time, the cyan and magenta, yellow, and black toner images formed on the photosensitive drums 10, 20, 30, and 40 are formed on the metal cores of the primary intermediate transfer drums 51 and 52, respectively. A primary transfer voltage is applied to transfer electrostatically onto the primary intermediate transfer drums 51 and 52. At this time, the resistance values of the primary intermediate transfer drums 51 and 52 (when applying 100 V at 22 ° C./55% RH environment; hereinafter, the resistance values unless otherwise specified are measured under these measurement conditions). ×
When it is higher than about 10 8.5 Ω, the primary transfer voltage applied to the primary intermediate transfer drums 51 and 52 is maintained in order to maintain the charge injected into the nip between the photosensitive drum and the primary intermediate transfer drum for performing the primary transfer. Must be set high. However, when a high primary transfer voltage is applied to the primary intermediate transfer drums 51 and 52, transfer blur of the toner images transferred on the primary intermediate transfer drums 51 and 52 (toner scatter around the transfer images) is deteriorated. Therefore, the primary intermediate transfer drum 5
By setting the resistance values of 1,52 to about 1 × 10 6 Ω to about 1 × 10 8 Ω, the primary transfer voltage can be set low, and the transfer blur can be suppressed.

【００４６】なお、この実施例１では、一次中間転写ド
ラム51, 52の表面電位が＋３００Ｖ程度に設定されてい
るが、当該一次中間転写ドラム51, 52は、その芯金に＋
３５０Ｖ程度の電圧が印加され、電圧減衰によって表面
電位が＋３００Ｖ程度になるように構成されている。In the first embodiment, the surface potentials of the primary intermediate transfer drums 51 and 52 are set to about +300 V. However, the primary intermediate transfer drums 51 and 52 are provided with +
A voltage of about 350 V is applied, and the surface potential becomes about +300 V due to the voltage decay.

【００４７】次に、上記一次中間転写ドラム51上に多重
に転写されたシアン及びマゼンタ色のトナー像と、一次
中間転写ドラム52上に多重に転写されたイエロー及び黒
色のトナー像は、二次中間転写ドラム53と接触する二次
転写位置において、当該二次中間転写ドラム53上に転写
される。その際、上記二次中間転写ドラム53の表面電位
を所定の電位に設定するために、当該二次中間転写ドラ
ム53の芯金に所定の電圧を印加したり、二次中間転写ド
ラム53の表面に当該二次中間転写ドラム53を帯電させる
部材を押し当てるなどの手段が採られる。Next, the cyan and magenta toner images multiplexed on the primary intermediate transfer drum 51 and the yellow and black toner images multiplexed on the primary intermediate transfer drum 52 are At a secondary transfer position in contact with the intermediate transfer drum 53, the image is transferred onto the secondary intermediate transfer drum 53. At this time, in order to set the surface potential of the secondary intermediate transfer drum 53 to a predetermined potential, a predetermined voltage is applied to the metal core of the secondary intermediate transfer drum 53, or the surface potential of the secondary intermediate transfer drum 53 is changed. For example, means for pressing the member for charging the secondary intermediate transfer drum 53 may be employed.

【００４８】ところで、この実施例１では、二次中間転
写ドラム53の抵抗値を、一次中間転写ドラム51, 52より
高く設定するように構成されている。これは、二次中間
転写ドラム53の抵抗値を高く設定することにより、二次
転写ニップ部でのトナーに対する電荷の注入を抑制し、
逆極性トナーの発生を防止し、リトランスファーによる
転写残り量を極力少なくするためである。例えば、一次
中間転写ドラム51, 52の抵抗値を１×１０8 Ωに設定す
るとき、二次中間転写ドラム53の抵抗値は、それよりも
高い１×１０9 Ωに設定することになる。In the first embodiment, the resistance value of the secondary intermediate transfer drum 53 is set higher than that of the primary intermediate transfer drums 51 and 52. This is because by setting the resistance value of the secondary intermediate transfer drum 53 high, the injection of electric charge to the toner in the secondary transfer nip portion is suppressed,
This is to prevent generation of toner of the opposite polarity and minimize the transfer remaining amount by retransfer. For example, when the resistance values of the primary intermediate transfer drums 51 and 52 are set to 1 × 10 8 Ω, the resistance value of the secondary intermediate transfer drum 53 is set to 1 × 10 9 Ω, which is higher than that.

【００４９】さらに説明すると、二次中間転写ドラム53
の抵抗値を、一次中間転写ドラム51, 52より高く設定す
ることにより、図４に示すように、一次中間転写ドラム
51,52上に多重に転写されたマイナス極性のシアン及び
マゼンタ色のトナー像Ｔと、同じくマイナス極性のイエ
ロー及び黒色のトナー像Ｔを、二次中間転写ドラム53上
に転写する際に、相対的に抵抗値が高く設定された二次
中間転写ドラム53から一次中間転写ドラム51, 52に対す
る電荷の注入が抑制される。そのため、二次中間転写ド
ラム53から一次中間転写ドラム51, 52に注入される電荷
によって、一次中間転写ドラム51, 52上のトナー像Ｔが
逆極性（プラス極性）に帯電され、逆極性トナーＴ’が
発生するのを防止することができ、この逆極性に帯電さ
れたトナーＴ’が、再度一次中間転写ドラム51, 52側に
転写される、所謂”リトランスファー”による転写残り
量を極力少なくすることができ、駆動系の簡易化や装置
の小型化を可能とし、又クリーニング装置を設けずに感
光体ドラム10, 20, 30, 40の長寿命化を可能とした場合
であっても、転写効率を大幅に向上させることによ
り、”転写ゴースト”や濃度変動などの発生を確実に防
止し、高画質のカラー画像を形成することが可能とな
る。More specifically, the secondary intermediate transfer drum 53
Is set higher than that of the primary intermediate transfer drums 51 and 52, as shown in FIG.
When the negative polarity cyan and magenta toner images T multiplexly transferred onto 51 and 52 and the same negative polarity yellow and black toner images T are transferred onto the secondary intermediate transfer drum 53, The injection of charges from the secondary intermediate transfer drum 53, which has a relatively high resistance value, to the primary intermediate transfer drums 51, 52 is suppressed. Therefore, the toner image T on the primary intermediate transfer drums 51 and 52 is charged to the opposite polarity (positive polarity) by the electric charge injected from the secondary intermediate transfer drum 53 to the primary intermediate transfer drums 51 and 52, and the opposite polarity toner T Is generated, and the toner T ′ charged to the opposite polarity is transferred to the primary intermediate transfer drums 51 and 52 again, so that the remaining transfer amount due to the so-called “retransfer” is minimized. Even if the simplification of the drive system and the miniaturization of the device are possible, and the life of the photosensitive drums 10, 20, 30, and 40 can be extended without providing a cleaning device, By greatly improving the transfer efficiency, the occurrence of “transfer ghost” and density fluctuation can be reliably prevented, and a high-quality color image can be formed.

【００５０】また、一次中間転写ドラム51, 52や二次中
間転写ドラム53には、シリコンゴム等からなるゴム層の
表面にフッ素ラテックスを塗布し焼成したものや、シリ
コンゴム等からなるゴム層の表面にアクリル系樹脂を塗
布したものを使用することにより、これら一次中間転写
ドラム51, 52や二次中間転写ドラム53の表面とトナー像
との間に作用するファンデルワールス力等の分子間力が
低減させることができ、静電気的な作用とともに転写効
率をより一層向上させることができる。The primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 may be formed by applying fluorine latex to the surface of a rubber layer made of silicon rubber or the like and baking it, or by forming a rubber layer made of silicon rubber or the like. By using an acrylic resin applied on the surface, the intermolecular force such as van der Waals force acting between the surface of the primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 and the toner image is used. Can be reduced, and the transfer efficiency can be further improved together with the electrostatic action.

【００５１】さらに、この実施例１では、一次中間転写
ドラム51, 52の表面速度と二次中間転写ドラム53の表面
速度に差を設けるように構成したので、一次中間転写ド
ラム51, 52と二次中間転写ドラム53の接触転写部で、一
次中間転写ドラム51, 52の表面速度と二次中間転写ドラ
ム53の表面速度に差を設けることにより、一次中間転写
ドラム51, 52から二次中間転写ドラム53へのトナー像の
転写効率を一層向上させることができる。Further, in the first embodiment, since the surface speeds of the primary intermediate transfer drums 51 and 52 and the surface speed of the secondary intermediate transfer drum 53 are set to be different, the primary intermediate transfer drums 51 and 52 are By providing a difference between the surface speeds of the primary intermediate transfer drums 51 and 52 and the surface speed of the secondary intermediate transfer drum 53 at the contact transfer section of the secondary intermediate transfer drum 53, the secondary intermediate transfer from the primary intermediate transfer drums 51 and 52 is performed. The transfer efficiency of the toner image to the drum 53 can be further improved.

【００５２】実験例１ 次に、本発明者等は、一次中間転写体と二次中間転写体
の接触転写部で、一次中間転写体の表面速度と二次中間
転写体の表面速度に差を設けることにより、トナー像の
転写効率がどのように向上するかを確認するため、一次
中間転写体と二次中間転写体を回転駆動するため、これ
らの中間転写体に取り付けられた駆動ギアの歯数を変
え、一次中間転写体と二次中間転写体の表面速度を変化
させ、一次中間転写体上の転写残りのトナー量を測定す
る実験を行った。Experimental Example 1 Next, the present inventors made a difference between the surface speed of the primary intermediate transfer member and the surface speed of the secondary intermediate transfer member at the contact transfer portion between the primary intermediate transfer member and the secondary intermediate transfer member. In order to confirm how the transfer efficiency of the toner image is improved by the provision, the rotation of the primary intermediate transfer member and the secondary intermediate transfer member is performed. An experiment was conducted in which the number of toner particles was changed and the surface speeds of the primary intermediate transfer member and the secondary intermediate transfer member were changed to measure the amount of untransferred toner on the primary intermediate transfer member.

【００５３】実験条件は、一次中間転写ドラム51, 52と
して、外径；４２ｍｍ、ゴム厚；５ｍｍ、シリコンゴム
層の表面にフッ素ラテックスを塗布し焼成したものを用
いた。この一次中間転写ドラム51, 52の抵抗値は、１×
１０8 Ωであった。また、二次中間転写ドラム53として
は、外径；４２ｍｍ、ゴム厚；１ｍｍ、シリコンゴム層
の表面にフッ素ラテックスを塗布し焼成したものを用い
た。この一次中間転写ドラム51, 52の抵抗値は、１×１
０9 Ωであった。さらに、プロセススピード（一次中間
転写ドラム51, 52の表面速度）は、１００ｍｍ／ｓｅ
ｃ、一次中間転写ドラム51, 52と二次中間転写ドラム53
の食い込み量は、０．５ｍｍ、現像トナー量は０．５ｍ
ｇ／ｃｍ2 にそれぞれ設定した。The experimental conditions were such that the primary intermediate transfer drums 51 and 52 had an outer diameter of 42 mm, a rubber thickness of 5 mm, and a surface of a silicone rubber layer coated with fluorine latex and fired. The resistance value of the primary intermediate transfer drums 51 and 52 is 1 ×
It was 10 8 Ω. The secondary intermediate transfer drum 53 used had an outer diameter of 42 mm, a rubber thickness of 1 mm, and a surface of a silicone rubber layer coated with fluorine latex and fired. The resistance value of the primary intermediate transfer drums 51 and 52 is 1 × 1
It was 9 Ω. Further, the process speed (the surface speed of the primary intermediate transfer drums 51 and 52) is 100 mm / sec.
c, primary intermediate transfer drums 51 and 52 and secondary intermediate transfer drum 53
The amount of bite is 0.5 mm and the amount of developed toner is 0.5 m
g / cm 2 .

【００５４】実験方法は、一次中間転写ドラム51, 52上
のトナー像のパッチを静電的に二次中間転写ドラム53に
転写させ、この時一次中間転写ドラム51, 52上に残った
未転写トナー像をメンデイングテープで採取し、メンデ
イングテープに転写されたトナー像の濃度を光学式濃度
計Ｘ−Ｒｉｔｅ９３８（Ｘ−Ｒｉｔｅ社製）で測定し
た。The experimental method is that the toner image patches on the primary intermediate transfer drums 51 and 52 are electrostatically transferred to the secondary intermediate transfer drum 53, and the untransferred portions remaining on the primary intermediate transfer drums 51 and 52 at this time. The toner image was collected with a mending tape, and the density of the toner image transferred to the mending tape was measured with an optical densitometer X-Rite938 (manufactured by X-Rite).

【００５５】二次中間転写ドラム53の速度は、９６．９
ｍｍ／ｓｅｃ、９８．４ｍｍ／ｓｅｃ、９９．２ｍｍ／
ｓｅｃ、１００ｍｍ／ｓｅｃ、１００．２ｍｍ／ｓｅ
ｃ、１０１．６ｍｍ／ｓｅｃ、１０３．３ｍｍ／ｓｅｃ
にそれぞれ変化させた。The speed of the secondary intermediate transfer drum 53 is 96.9.
mm / sec, 98.4 mm / sec, 99.2 mm /
sec, 100mm / sec, 100.2mm / sec
c, 101.6 mm / sec, 103.3 mm / sec
Was changed respectively.

【００５６】図５は上記実験の結果を示すものである。FIG. 5 shows the results of the above experiment.

【００５７】この図５から明らかなように、一次中間転
写ドラム51, 52と二次中間転写ドラム53の表面速度差を
１％以上つければ、転写残りはほとんどなくなることが
わかった。また、速度差を付けた時の転写残りをメンデ
イングテープに転写したトナー像は、目視ではほとんど
判別できないレベルであった。さらに、一次中間転写ド
ラム51, 52と二次中間転写ドラム53の表面速度差を＋
３．０％程度に設定することにより、転写残りをほとん
ど０％にすることができることがわかる。As is apparent from FIG. 5, it is found that when the surface speed difference between the primary intermediate transfer drums 51, 52 and the secondary intermediate transfer drum 53 is set to 1% or more, almost no transfer residue remains. Further, the toner image obtained by transferring the transfer residue at the time of applying the speed difference to the mending tape was at a level which could hardly be discriminated visually. Further, the surface speed difference between the primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 is increased by +
It can be seen that the transfer residue can be reduced to almost 0% by setting the value to about 3.0%.

【００５８】以上、説明したように、一次中間転写ドラ
ム51, 52の抵抗値より二次中間転写ドラム53の抵抗値を
高く設定し、これらの接触部で一次中間転写ドラム51,
52と二次中間転写ドラム53の表面速度に、−０．５％か
ら−５．０％もしくは＋０．５％から＋５．０％の速度
差を設けることにより、二次転写効率を極力高めること
ができ、転写残りによる転写ゴーストのプリントアウト
の抑制を行うことができることがわかる。転写効率を高
めることができるので、同時に転写のための電位差を低
く抑えることができ、転写ブラーも同時に抑制すること
ができる。As described above, the resistance value of the secondary intermediate transfer drum 53 is set higher than the resistance value of the primary intermediate transfer drums 51 and 52, and the primary intermediate transfer drum 51,
By providing a speed difference between -0.5% and -5.0% or + 0.5% and + 5.0% between the surface speeds of the secondary transfer drum 52 and the secondary intermediate transfer drum 53, the secondary transfer efficiency is increased as much as possible. It can be seen that printout of transfer ghost due to transfer residue can be suppressed. Since the transfer efficiency can be increased, the potential difference for transfer can be suppressed at the same time, and transfer blur can be suppressed at the same time.

【００５９】また、感光体ドラムにクリーニング装置が
ない場合の画像形成装置において、感光体ドラムに戻る
転写残りトナーを極力少なくすることができるので、感
光体ドラムに接触する帯電部材の汚れ抑制や現像機にお
ける混色抑制をすることができる。In an image forming apparatus in which a cleaning device is not provided on a photosensitive drum, transfer residual toner returning to the photosensitive drum can be reduced as much as possible. It is possible to suppress color mixing in the machine.

【００６０】〔実施例２〕この発明の実施例２につい
て、前記実施例と同一の部分には同一の符号を付して説
明すると、この実施例２では、像担持体よりも一次中間
転写体の表面速度を速く設定し、二次中間転写体の表面
速度を一次中間転写体の表面速度よりも遅く設定するよ
うに構成されている。[Second Embodiment] The second embodiment of the present invention will be described by assigning the same reference numerals to the same parts as those of the first embodiment. In the second embodiment, a primary intermediate transfer member is used rather than an image carrier. Is set to be high, and the surface speed of the secondary intermediate transfer member is set to be lower than the surface speed of the primary intermediate transfer member.

【００６１】すなわち、この実施例２のフルカラー画像
形成装置は、一次中間転写ドラム51, 52の表面速度を感
光体ドラム10, 20, 30, 40の表面速度よりも速く設定し
た場合、さらに二次中間転写ドラム53の表面速度を一次
中間転写ドラム51, 52よりも速めると、像が伸び切って
しまい、像抜けや細線画像の抜けなどが発生してしまう
虞れがある。That is, in the full-color image forming apparatus of the second embodiment, when the surface speed of the primary intermediate transfer drums 51 and 52 is set higher than the surface speed of the photosensitive drums 10, 20, 30, and 40, the secondary If the surface speed of the intermediate transfer drum 53 is set higher than that of the primary intermediate transfer drums 51 and 52, the image may be stretched completely, and image missing or thin line image missing may occur.

【００６２】そこで、この実施例２では、これを防ぐた
めに、二次中間転写ドラム53の表面速度を一次中間転写
ドラム51, 52の表面速度よりも遅く設定することによ
り、一次中間転写ドラム51, 52と二次中間転写ドラム53
との間に速度差を付け、像が伸びて像抜けや細線画像の
抜けなどが発生するのを防止することができる。Therefore, in the second embodiment, in order to prevent this, the surface speed of the secondary intermediate transfer drum 53 is set lower than the surface speed of the primary intermediate transfer drums 51, 52, so that the primary intermediate transfer drum 51, 52 and secondary intermediate transfer drum 53
And a speed difference can be provided to prevent the image from being stretched to cause image omission or omission of a fine line image.

【００６３】例えば、プロセススピード（感光体の表面
速度）を１００ｍｍ／ｓｅｃとし、一次中間転写ドラム
51, 52の表面速度を１０１．５ｍｍ／ｓｅｃと設定する
場合、二次中間転写ドラム53の表面速度を１００ｍｍ／
ｓｅｃに設定すると、二次中間転写ドラム53の表面速度
差は約−１．５％となる。この場合、二次中間転写ドラ
ム53上に転写された像の感光体ドラム10, 20, 30, 40上
に形成された像に対する伸びを解消することができる。For example, the process speed (surface speed of the photosensitive member) is set to 100 mm / sec, and the primary intermediate transfer drum
When the surface speeds of 51 and 52 are set to 101.5 mm / sec, the surface speed of the secondary intermediate transfer drum 53 is set to 100 mm / sec.
When set to sec, the surface speed difference of the secondary intermediate transfer drum 53 is about -1.5%. In this case, the extension of the image transferred on the secondary intermediate transfer drum 53 to the image formed on the photosensitive drums 10, 20, 30, and 40 can be eliminated.

【００６４】さらに、二次中間転写ドラム53の表面速度
を１００ｍｍ／ｓｅｃではなく、９８．５ｍｍ／ｓｅｃ
とすると、二次中間転写ドラム53の表面速度差は、約−
３．０％となる。この時の二次中間転写ドラム53上での
像の伸びは、約−１．５％となる。そこで、像の伸びを
調整するため、露光装置を調整し感光体ドラム10, 20,
30, 40上に＋１．５％に伸ばした像を形成させるか、最
終転写手段において記録用紙Ｐの速度をプロセススピー
ドに対して＋１．５％の速度差をつけて像の伸びを調整
するなどの手段を採ることにより、適正な画像を形成す
ることが可能となる。Further, the surface speed of the secondary intermediate transfer drum 53 is set to 98.5 mm / sec instead of 100 mm / sec.
Then, the surface speed difference of the secondary intermediate transfer drum 53 is about-
3.0%. At this time, the expansion of the image on the secondary intermediate transfer drum 53 is about -1.5%. Therefore, in order to adjust the elongation of the image, the exposure device is adjusted and the photosensitive drums 10, 20, 20 are adjusted.
For example, an image expanded to + 1.5% is formed on 30, 40 or the elongation of the image is adjusted by making the speed of the recording paper P + 1.5% different from the process speed in the final transfer means. By employing the means described above, an appropriate image can be formed.

【００６５】その他の構成及び作用は、前記実施例１と
同様であるので、その説明を省略する。The other configuration and operation are the same as those of the first embodiment, and the description thereof will be omitted.

【００６６】〔実施例３〕この発明の実施例３につい
て、前記実施例と同一の部分には同一の符号を付して説
明すると、この実施例３では、像担持体よりも一次中間
転写体の表面速度を遅く設定し、二次中間転写体の表面
速度を一次中間転写体の表面速度よりも速く設定するよ
うに構成されている。[Embodiment 3] A third embodiment of the present invention will be described by assigning the same reference numerals to the same parts as those in the above embodiment. In the third embodiment, a primary intermediate transfer member is used rather than an image carrier. Is set to be lower, and the surface speed of the secondary intermediate transfer member is set higher than the surface speed of the primary intermediate transfer member.

【００６７】すなわち、この実施例２のフルカラー画像
形成装置は、一次中間転写ドラム51, 52の表面速度を感
光体ドラム10, 20, 30, 40の表面速度よりも遅くする場
合、さらに二次中間転写ドラム53の表面速度を一次中間
転写ドラム51, 52よりも遅くすると、像が縮んでしま
い、像乱れや像濃度横縞ムラなどが発生してしまうこと
になる。これを防ぐために、この場合は二次中間転写ド
ラム53の表面速度を一次中間転写ドラム51, 52の表面速
度よりも速く設定することにより、二次中間転写体と一
次中間転写体表面間に速度差をつけるように構成されて
いる。That is, in the full-color image forming apparatus of the second embodiment, when the surface speeds of the primary intermediate transfer drums 51 and 52 are lower than the surface speeds of the photosensitive drums 10, 20, 30, and 40, the secondary intermediate transfer drums are further reduced. If the surface speed of the transfer drum 53 is lower than that of the primary intermediate transfer drums 51 and 52, the image will shrink, and image disturbance and image density horizontal stripe unevenness will occur. In order to prevent this, in this case, the surface speed of the secondary intermediate transfer drum 53 is set higher than the surface speed of the primary intermediate transfer drums 51 and 52, so that the speed between the secondary intermediate transfer body and the surface of the primary intermediate transfer body is reduced. It is configured to make a difference.

【００６８】例えば、プロセススピード（感光体の表面
速度）を１００ｍｍ／ｓｅｃとし、一次中間転写ドラム
51, 52の表面速度を９８．５ｍｍ／ｓｅｃに設定する場
合、二次中間転写ドラム53の表面速度を１００ｍｍ／ｓ
ｅｃに設定すると、二次中間転写ドラム53の表面速度差
は約＋１．５％となる。この場合、二次中間転写ドラム
53上に形成された像からの縮みはなくなる。For example, the process speed (surface speed of the photosensitive member) is set to 100 mm / sec, and the primary intermediate transfer drum
When setting the surface speed of 51, 52 to 98.5 mm / sec, the surface speed of the secondary intermediate transfer drum 53 is set to 100 mm / s.
When set to ec, the surface speed difference of the secondary intermediate transfer drum 53 is about + 1.5%. In this case, the secondary intermediate transfer drum
The shrinkage from the image formed on 53 disappears.

【００６９】さらに、二次中間転写ドラム53の表面速度
を１００ｍｍ／ｓｅｃではなく、１０１．５ｍｍ／ｓｅ
ｃとすると、二次中間転写ドラム53の表面速度差は、約
＋３．０％となる。一次中間転写ドラム51, 52と二次中
間転写ドラム53の表面速度差が、約＋３．０％である
と、図５から分かるように、転写残りは略０％となる。
この時の二次中間転写ドラム53上での像の伸びは、約＋
１．５％となる。像の伸びを調整するため、露光装置を
調整し感光体ドラム10, 20, 30, 40上に−１．５％に伸
ばした像を形成させるか、最終転写手段において記録用
紙Ｐの速度をプロセススピードに対して−１．５％の速
度差をつけて像の伸びを調整するなどの手段を採ること
により、適正な画像を形成することが可能となる。Further, the surface speed of the secondary intermediate transfer drum 53 is set to 101.5 mm / sec instead of 100 mm / sec.
Assuming that c, the surface speed difference of the secondary intermediate transfer drum 53 is about + 3.0%. When the surface speed difference between the primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 is about + 3.0%, as can be seen from FIG. 5, the transfer remainder is approximately 0%.
At this time, the extension of the image on the secondary intermediate transfer drum 53 is approximately +
1.5%. In order to adjust the elongation of the image, the exposure device is adjusted to form an image expanded to -1.5% on the photosensitive drums 10, 20, 30, and 40, or the speed of the recording paper P is controlled by the final transfer means. By taking measures such as adjusting the elongation of the image by giving a speed difference of -1.5% to the speed, it is possible to form an appropriate image.

【００７０】その他の構成及び作用は、前記実施例１と
同様であるので、その説明を省略する。The other configuration and operation are the same as those of the first embodiment, and the description thereof will be omitted.

【００７１】なお、前記実施例では、一次中間転写ドラ
ム51, 52と二次中間転写ドラム53として、同一径のもの
を使用したが、これに限定されるものではなく、図６に
示すように、一次中間転写ドラム51, 52の直径を二次中
間転写ドラム53よりも大きく設定しても良い。In the above embodiment, the primary intermediate transfer drums 51 and 52 and the secondary intermediate transfer drum 53 have the same diameter. However, the present invention is not limited to this. As shown in FIG. Alternatively, the diameter of the primary intermediate transfer drums 51 and 52 may be set larger than that of the secondary intermediate transfer drum 53.

【００７２】また、前記実施例では、４つの感光体ドラ
ム10, 20, 30, 40を垂直方向に配置したが、これらの感
光体ドラム10, 20, 30, 40を水平方向に沿って配置して
も良い。さらに、図７に示すように、２つの感光体ドラ
ム10,40 は、一次中間転写ドラム51, 52を介して二次中
間転写ドラム53上にトナー像を転写し、他の２つの感光
体ドラム20, 30は、一次中間転写ドラム51, 52を介さず
に直接二次中間転写ドラム53上にトナー像を転写するよ
うに構成しても、図８に示すように、２つの感光体ドラ
ム10,20 は、一次中間転写ドラム51, 52を介して二次中
間転写ドラム53上にトナー像を転写し、他の２つの感光
体ドラム30, 40は、一次中間転写ドラム51, 52を介さず
に直接二次中間転写ドラム53上にトナー像を転写するよ
うに構成しても良い。In the above embodiment, the four photosensitive drums 10, 20, 30, 40 are arranged vertically, but these photosensitive drums 10, 20, 30, 40 are arranged horizontally. May be. Further, as shown in FIG. 7, the two photosensitive drums 10 and 40 transfer the toner image onto the secondary intermediate transfer drum 53 via the primary intermediate transfer drums 51 and 52, and the other two photosensitive drums. Even if the toner image transfer units 20 and 30 are configured to directly transfer the toner image onto the secondary intermediate transfer drum 53 without going through the primary intermediate transfer drums 51 and 52, as shown in FIG. , 20 transfer the toner image onto the secondary intermediate transfer drum 53 via the primary intermediate transfer drums 51, 52, and the other two photosensitive drums 30, 40 are transferred without passing through the primary intermediate transfer drums 51, 52. May be configured to directly transfer the toner image onto the secondary intermediate transfer drum 53.

【００７３】又さらに、図９に示すように、感光体ドラ
ムを６つ設け、これら６つの感光体ドラムのうち、両端
部の２つの感光体ドラムは、一次中間転写ドラム51, 52
を介して二次中間転写ドラム53上にトナー像を転写し、
他の２つの感光体ドラム20,30は、一次中間転写ドラム5
1, 52を介さずに直接二次中間転写ドラム53上にトナー
像を転写するように構成しても良い。また、図１０に示
すように、感光体ドラムを８つ設け、これら８つの感光
体ドラムを２つずつ一次中間転写ドラムに接触させ、こ
れら４つの一次中間転写ドラムを介して２つの二次中間
転写ドラム上にトナー像を転写し、更に、これらの２つ
の二次中間転写ドラム上に転写されたトナー像を１つの
三次中間転写ドラム上に転写するように構成しても良
い。Further, as shown in FIG. 9, six photosensitive drums are provided, and two photosensitive drums at both ends of the six photosensitive drums are primary intermediate transfer drums 51 and 52.
Transfer the toner image onto the secondary intermediate transfer drum 53 via
The other two photosensitive drums 20 and 30 are the primary intermediate transfer drum 5
The toner image may be directly transferred onto the secondary intermediate transfer drum 53 without using the media 1 and 52. Further, as shown in FIG. 10, eight photosensitive drums are provided, and each of the eight photosensitive drums is brought into contact with the primary intermediate transfer drum two by two. The toner image may be transferred onto the transfer drum, and further, the toner image transferred onto these two secondary intermediate transfer drums may be transferred onto one tertiary intermediate transfer drum.

【００７４】[0074]

【発明の効果】この発明の画像形成装置によれば、駆動
系の簡易化や装置の小型化を可能とし、又感光体等の像
担持体の長寿命化を可能とした場合であっても、転写効
率を大幅に向上させることにより、”転写ゴースト”や
濃度変動などの発生を確実に防止し、高画質のカラー画
像を形成することが可能な画像形成装置を提供すること
ができる。According to the image forming apparatus of the present invention, the driving system can be simplified and the apparatus can be downsized, and even if the life of an image carrier such as a photoconductor can be extended. Further, by greatly improving the transfer efficiency, it is possible to provide an image forming apparatus capable of forming a high-quality color image by reliably preventing "transfer ghost" and density fluctuation.

【図面の簡単な説明】[Brief description of the drawings]

【図１】 図１は、この発明の実施例１に係るフルカラ
ー画像形成装置を示す構成説明図である。FIG. 1 is a configuration explanatory diagram illustrating a full-color image forming apparatus according to a first embodiment of the present invention.

【図２】 図２は、図１に示す実施例１の画像形成時の
電圧印加状態を示す説明図である。FIG. 2 is an explanatory diagram illustrating a voltage application state during image formation according to the first embodiment illustrated in FIG. 1;

【図３】 図３は、一次中間転写ドラムを示す構成図で
ある。FIG. 3 is a configuration diagram illustrating a primary intermediate transfer drum.

【図４】 図４は、一次中間転写ドラムと二次中間転写
ドラムとの電圧の印加状態を示す説明図である。FIG. 4 is an explanatory diagram illustrating a voltage application state of a primary intermediate transfer drum and a secondary intermediate transfer drum.

【図５】 図５は、一次中間転写ドラムと二次中間転写
ドラムとの表面速度の差による転写残りトナーを示すグ
ラフである。FIG. 5 is a graph showing transfer residual toner depending on a difference in surface speed between a primary intermediate transfer drum and a secondary intermediate transfer drum.

【図６】 図６は、この発明の他の実施例に係るフルカ
ラー画像形成装置を示す構成説明図である。FIG. 6 is an explanatory diagram illustrating a configuration of a full-color image forming apparatus according to another embodiment of the present invention.

【図７】 図７は、この発明の他の実施例に係るフルカ
ラー画像形成装置を示す構成説明図である。FIG. 7 is a configuration explanatory view showing a full-color image forming apparatus according to another embodiment of the present invention.

【図８】 図８は、この発明の他の実施例に係るフルカ
ラー画像形成装置を示す構成説明図である。FIG. 8 is a structural explanatory view showing a full-color image forming apparatus according to another embodiment of the present invention.

【図９】 図９は、この発明の他の実施例に係るフルカ
ラー画像形成装置を示す構成説明図である。FIG. 9 is a structural explanatory view showing a full-color image forming apparatus according to another embodiment of the present invention.

【図１０】 図１０は、この発明の他の実施例に係るフ
ルカラー画像形成装置を示す構成説明図である。FIG. 10 is a configuration explanatory view showing a full-color image forming apparatus according to another embodiment of the present invention.

【図１１】 図１１は、従来のフルカラー画像形成装置
を示す構成説明図である。FIG. 11 is a configuration explanatory view showing a conventional full-color image forming apparatus.

【符号の説明】 10,20,30,40…感光体（像担持体）、 11,21,31,41…帯
電ロール（接触型帯電装置）、12,22,32,42 …露光装
置、 13,23,33,43…現像装置、 51,52…一次中間転写ド
ラム（中間転写体）、53…二次中間転写ドラム（中間転
写体）、61…最終転写ロール（最終転写体）、Ｐ…用紙
（記録シート）。[Description of Signs] 10, 20, 30, 40: Photoconductor (image carrier), 11, 21, 31, 41: Charging roll (contact type charging device), 12, 22, 32, 42: Exposure device, 13 , 23,33,43 ... Developing device, 51,52 ... Primary intermediate transfer drum (intermediate transfer member), 53 ... Secondary intermediate transfer drum (intermediate transfer member), 61 ... Final transfer roll (final transfer member), P ... Paper (recording sheet).

───────────────────────────────────────────────────── フロントページの続き (72)発明者 山本 隆一 埼玉県岩槻市府内３丁目７番１号、富士ゼ ロックス株式会社岩槻事業所内 (72)発明者 北河 裕介 埼玉県岩槻市府内３丁目７番１号、富士ゼ ロックス株式会社岩槻事業所内 Ｆターム(参考） 2H030 AA06 AB02 BB23 BB42 BB46 BB53 2H032 AA05 BA08 BA23  ──────────────────────────────────────────────────続 き Continuing on the front page (72) Ryuichi Yamamoto, Inventor 3-7-1, Fuuchi, Iwatsuki-shi, Saitama, Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Yusuke Kitagawa 3-7-1, Fuuchi, Iwatsuki-shi, Saitama No. 1, Fuji Xerox Co., Ltd. Iwatsuki Office F-term (reference) 2H030 AA06 AB02 BB23 BB42 BB46 BB53 2H032 AA05 BA08 BA23

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 互いに色の異なったトナー像が形成され
る複数の像担持体と、これら複数の像担持体のうちの少
なくとも一部からトナー像が転写される一次中間転写体
と、少なくとも当該一次中間転写体からトナー像が転写
される二次中間転写体とを備え、前記複数の像担持体上
に形成された色の異なったトナー像のうち少なくとも一
部のトナー像は、一次中間転写体を介して二次中間転写
体上に多重に転写することにより、カラーの画像を形成
する画像形成装置において、前記像担持体からトナー像
が転写される一次中間転写体の抵抗値より、当該一次中
間転写体からトナー像が転写される二次中間転写体の抵
抗値を高く設定したことを特徴とする画像形成装置。A plurality of image carriers on which toner images of different colors are formed; a primary intermediate transfer member onto which a toner image is transferred from at least a part of the plurality of image carriers; A secondary intermediate transfer member on which a toner image is transferred from the primary intermediate transfer member, wherein at least a part of the toner images of different colors formed on the plurality of image carriers is a primary intermediate transfer member. In an image forming apparatus that forms a color image by transferring multiple images onto a secondary intermediate transfer body via a body, the resistance value of the primary intermediate transfer body onto which a toner image is transferred from the image bearing member An image forming apparatus, wherein a resistance value of a secondary intermediate transfer member to which a toner image is transferred from a primary intermediate transfer member is set high. 【請求項２】 互いに色の異なったトナー像が形成され
る複数の像担持体と、これら複数の像担持体からトナー
像が転写される複数の一次中間転写体と、これら複数の
一次中間転写体からトナー像が多重に転写される二次中
間転写体とを備え、前記複数の像担持体上に形成された
色の異なったトナー像を、複数の一次中間転写体を介し
て二次中間転写体上に多重に転写することにより、カラ
ーの画像を形成する画像形成装置において、 前記像担持体からトナー像が転写される一次中間転写体
の抵抗値より、当該一次中間転写体からトナー像が転写
される二次中間転写体の抵抗値を高く設定したことを特
徴とする画像形成装置。2. A plurality of image carriers on which toner images of different colors are formed, a plurality of primary intermediate transfer members onto which toner images are transferred from the plurality of image carriers, and a plurality of primary intermediate transfer members And a secondary intermediate transfer member on which a toner image is transferred in a multiplex manner from the body, wherein the toner images of different colors formed on the plurality of image carriers are subjected to secondary intermediate transfer via a plurality of primary intermediate transfer members. In an image forming apparatus that forms a color image by performing multiple transfer on a transfer member, a toner image is transferred from the primary intermediate transfer member based on a resistance value of the primary intermediate transfer member onto which the toner image is transferred from the image carrier. An image forming apparatus, wherein the resistance value of a secondary intermediate transfer member onto which is transferred is set high. 【請求項３】 互いに色の異なったトナー像が形成され
る複数の像担持体と、これら複数の像担持体のうちの少
なくとも一部からトナー像が転写される一次中間転写体
と、少なくとも当該一次中間転写体からトナー像が転写
される二次中間転写体とを備え、前記複数の像担持体上
に形成された色の異なったトナー像のうち少なくとも一
部のトナー像は、一次中間転写体を介して二次中間転写
体上に多重に転写することにより、カラーの画像を形成
する画像形成装置において、 前記像担持体からトナー像が転写される一次中間転写体
の抵抗値より、当該一次中間転写体からトナー像が転写
される二次中間転写体の抵抗値を高く設定するととも
に、前記一次中間転写体と二次中間転写体の接触転写部
で、一次中間転写体の表面速度と二次中間転写体の表面
速度に差を設けたことを特徴とする画像形成装置。3. A plurality of image carriers on which toner images of different colors are formed, a primary intermediate transfer body onto which a toner image is transferred from at least a part of the plurality of image carriers, and A secondary intermediate transfer member on which a toner image is transferred from the primary intermediate transfer member, wherein at least a part of the toner images of different colors formed on the plurality of image carriers is a primary intermediate transfer member. In an image forming apparatus that forms a color image by performing multiple transfer onto a secondary intermediate transfer body via a body, the resistance value of the primary intermediate transfer body to which a toner image is transferred from the image carrier While the resistance value of the secondary intermediate transfer body to which the toner image is transferred from the primary intermediate transfer body is set to be high, the surface speed of the primary intermediate transfer body and the contact speed of the primary intermediate transfer body and the secondary intermediate transfer body Secondary intermediate transfer An image forming apparatus characterized in that a difference between the surface speed of the. 【請求項４】 互いに色の異なったトナー像が形成され
る複数の像担持体と、これら複数の像担持体のうちの少
なくとも一部からトナー像が転写される一次中間転写体
と、少なくとも当該一次中間転写体からトナー像が転写
される二次中間転写体とを備え、前記複数の像担持体上
に形成された色の異なったトナー像のうち少なくとも一
部のトナー像は、一次中間転写体を介して二次中間転写
体上に多重に転写することにより、カラーの画像を形成
する画像形成装置において、 前記像担持体よりも一次中間転写体の表面速度を速く設
定し、二次中間転写体の表面速度を一次中間転写体の表
面速度よりも遅く設定したことを特徴とする画像形成装
置。4. A plurality of image carriers on which toner images of different colors are formed, a primary intermediate transfer body onto which a toner image is transferred from at least a part of the plurality of image carriers, and A secondary intermediate transfer member on which a toner image is transferred from the primary intermediate transfer member, wherein at least a part of the toner images of different colors formed on the plurality of image carriers is a primary intermediate transfer member. In an image forming apparatus that forms a color image by performing multiple transfer onto a secondary intermediate transfer body via a body, the surface speed of the primary intermediate transfer body is set higher than that of the image carrier, An image forming apparatus, wherein the surface speed of a transfer member is set lower than the surface speed of a primary intermediate transfer member. 【請求項５】 互いに色の異なったトナー像が形成され
る複数の像担持体と、これら複数の像担持体のうちの少
なくとも一部からトナー像が転写される一次中間転写体
と、少なくとも当該一次中間転写体からトナー像が転写
される二次中間転写体とを備え、前記複数の像担持体上
に形成された色の異なったトナー像のうち少なくとも一
部のトナー像は、一次中間転写体を介して二次中間転写
体上に多重に転写することにより、カラーの画像を形成
する画像形成装置において、 前記像担持体よりも一次中間転写体の表面速度を遅く設
定し、二次中間転写体の表面速度を一次中間転写体の表
面速度よりも速く設定したことを特徴とする画像形成装
置。5. A plurality of image carriers on which toner images of different colors are formed, a primary intermediate transfer body onto which a toner image is transferred from at least a part of the plurality of image carriers, and A secondary intermediate transfer member on which a toner image is transferred from the primary intermediate transfer member, wherein at least a part of the toner images of different colors formed on the plurality of image carriers is a primary intermediate transfer member. In an image forming apparatus that forms a color image by performing multiple transfer onto a secondary intermediate transfer body via a body, the surface speed of the primary intermediate transfer body is set lower than that of the image carrier, An image forming apparatus wherein the surface speed of a transfer member is set higher than the surface speed of a primary intermediate transfer member.
JP30150899A 1999-10-22 1999-10-22 Image forming device Pending JP2001117317A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP30150899A JP2001117317A (en) 1999-10-22 1999-10-22 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP30150899A JP2001117317A (en) 1999-10-22 1999-10-22 Image forming device

Publications (1)

Publication Number Publication Date
JP2001117317A true JP2001117317A (en) 2001-04-27

Family

ID=17897773

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003337514A (en) * 2002-05-21 2003-11-28 Fuji Xerox Co Ltd Image forming apparatus and developer recovery container used for the same
US6993281B2 (en) 2002-09-19 2006-01-31 Ricoh Company, Ltd. Image forming apparatus and process cartridge including flexible member
JP2007193369A (en) * 2001-05-29 2007-08-02 Fuji Xerox Co Ltd Image forming apparatus
US7295796B1 (en) 2002-08-30 2007-11-13 Ricoh Company, Ltd. Image forming apparatus having a temporary toner holding device and a toner collecting device
US8983323B2 (en) 2012-01-27 2015-03-17 Ricoh Company, Limited Color image forming apparatus with a line velocity difference set between image carriers

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007193369A (en) * 2001-05-29 2007-08-02 Fuji Xerox Co Ltd Image forming apparatus
JP2003337514A (en) * 2002-05-21 2003-11-28 Fuji Xerox Co Ltd Image forming apparatus and developer recovery container used for the same
US7295796B1 (en) 2002-08-30 2007-11-13 Ricoh Company, Ltd. Image forming apparatus having a temporary toner holding device and a toner collecting device
US6993281B2 (en) 2002-09-19 2006-01-31 Ricoh Company, Ltd. Image forming apparatus and process cartridge including flexible member
US7110699B2 (en) 2002-09-19 2006-09-19 Ricoh Company, Ltd. Image forming apparatus and process cartridge for use in the same
US8983323B2 (en) 2012-01-27 2015-03-17 Ricoh Company, Limited Color image forming apparatus with a line velocity difference set between image carriers

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