JPH06202492A - Image forming device - Google Patents

Image forming device

Info

Publication number
JPH06202492A
JPH06202492A JP4361256A JP36125692A JPH06202492A JP H06202492 A JPH06202492 A JP H06202492A JP 4361256 A JP4361256 A JP 4361256A JP 36125692 A JP36125692 A JP 36125692A JP H06202492 A JPH06202492 A JP H06202492A
Authority
JP
Japan
Prior art keywords
intermediate transfer
transfer roller
photosensitive drum
image
color
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
JP4361256A
Other languages
Japanese (ja)
Inventor
Akihiko Takeuchi
竹内　　昭彦
Koichi Tanigawa
耕一 谷川
Toshio Miyamoto
敏男 宮本
Kazuro Ono
和朗 小野
Minoru Matsukuma
稔 松隈
Takayasu Yunamochi
貴康 弓納持
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 JP4361256A priority Critical patent/JPH06202492A/en
Publication of JPH06202492A publication Critical patent/JPH06202492A/en
Pending legal-status Critical Current

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

Abstract

PURPOSE:To prevent a change in the tone of a color image caused by the irregu lar overlapping of the nonuniformity of a density due to a photosensitive drum and a transfer roller on a transfer material. CONSTITUTION:The photosensitive drum 1 is abutted on an intermediate transfer roller 6, to form a transfer nip part N. The toner images of each color of magenta M, cyan C, yellow Y and black B successively formed on the photosensitive drum 1 are successively transferred on the transfer roller 6 via the transfer nip part N, to laminate the toner images of four colors. At this time, the revolving speeds per unit-time of the photosensitive drum 1 and the intermediate transfer roller 5 are set so as to make one be the integral multiple of the other. Thus, on the toner images of four colors laminated on the transfer roller 6, gradation irregularities in the image caused by each of the thickness and irregularities in sensitivity of the photosensitive drum 1 and the resistance unevenness of the intermediate transfer roller 6 are never irregularly overlapped with each other on the transfer roller 6.

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、電子写真方式の複写機
やプリンタ等の画像形成装置に係り、詳しくは、画像担
持体上に形成したトナー像を、一旦、中間転写ローラ上
に中間転写し、その後、中間転写ローラ上から転写材上
に最終転写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 such as an electrophotographic copying machine or a printer. More specifically, the toner image formed on an image carrier is temporarily transferred onto an intermediate transfer roller. Then, the present invention relates to an image forming apparatus that performs final transfer from the intermediate transfer roller onto the transfer material.

【０００２】[0002]

【従来の技術】従来、電子写真方式を採用した複写機、
プリンタ等の画像形成装置としては、紙等の転写材上
に、直接、シアン（Ｃ）、マゼンタ（Ｍ）、イエロー
（Ｙ）、ブラック（Ｂ）などのトナー像を順番に重ねて
ゆく方式が一般に知られている。この方式では、１つの
感光ドラムを用いて順次画像形成を行い、このトナー像
をしっかりと支持された転写紙上に順次重ね合わせて行
くことにより、色ズレの生じない良好な画像が得られる
という利点がある。反面、この方式は、転写材を支持す
るのに、円筒状の転写ドラムなどの表面に転写材を巻き
つけて支持する必要があるため、腰の強い厚紙や薄手の
紙、特殊紙が扱えないという欠点があった。この欠点を
解決するための１つの方法として、誘電体ベルトの中間
転写体上に、上述Ｃ、Ｍ、Ｙ、Ｂなどのトナー像を順次
転写して行き、これを転写材上に一括転写するという方
法が知られている。2. Description of the Related Art Conventionally, a copying machine using an electrophotographic system,
As an image forming apparatus such as a printer, there is a method in which toner images of cyan (C), magenta (M), yellow (Y), black (B), etc. are directly superposed on a transfer material such as paper in order. Is generally known. In this method, an image is sequentially formed using one photosensitive drum, and the toner images are sequentially superposed on a firmly supported transfer paper, so that a good image without color misregistration can be obtained. There is. On the other hand, in this method, it is necessary to wind the transfer material around the surface of a cylindrical transfer drum or the like to support the transfer material, so that it is not possible to handle thick paper, thin paper, or special paper that has strong rigidity. There was a drawback. As one method for solving this drawback, the above-mentioned toner images of C, M, Y, B, etc. are sequentially transferred onto the intermediate transfer member of the dielectric belt, and are transferred at one time onto the transfer material. That method is known.

【０００３】しかしながら、この方法によれば、中間転
写体である誘電体ベルト上への転写時に、ベルト背面か
ら高電圧を印加しなければならず、これによる細線の飛
びちりやハーフトーン画像の乱れ、あるいは誘電体ベル
トの絶縁破損、といった問題が生じ、また、誘電体ベル
トの厚みをある程度薄くしなければならないが、このた
めにベルト駆動時のよりを防止する必要が生じるなど、
困難な点が多く存在した。However, according to this method, a high voltage must be applied from the back surface of the belt at the time of transfer onto the dielectric belt, which is an intermediate transfer member, and as a result, fine lines are scattered and halftone images are disturbed. , Or dielectric damage of the dielectric belt occurs, and the thickness of the dielectric belt must be reduced to some extent, but for this reason, it is necessary to prevent the belt from being driven.
There were many difficulties.

【０００４】そこで、もう１つの方法として、中抵抗の
弾性ローラで構成された、中間転写体を用い、これを感
光ドラムに当接させて、Ｃ、Ｍ、Ｙ、Ｂなどのトナー像
を順次転写してゆき、これを転写材上に一括転写すると
いう方法が考案された。この方法によれば、トナー飛び
散りのない良好な画像が得られ、駆動方式も簡易化でき
るとともに、バイアス電圧の印加で中間転写体を簡単に
清掃できるという利点がある。Therefore, as another method, an intermediate transfer member composed of an elastic roller having a medium resistance is used, and the intermediate transfer member is brought into contact with a photosensitive drum to sequentially form toner images of C, M, Y, B and the like. A method was devised in which transfer was carried out and this was collectively transferred onto a transfer material. This method has the advantages that a good image without toner scattering can be obtained, the driving system can be simplified, and the intermediate transfer member can be easily cleaned by applying a bias voltage.

【０００５】図３および図４にこの方法による画像形成
装置の一列を示す。FIG. 3 and FIG. 4 show one row of the image forming apparatus according to this method.

【０００６】図３において、感光ドラム（画像担持体）
１は、矢印Ｒ１方向に回転し、１次帯電ローラ２により
一様に帯電され、露光３により静電潜像が形成された
後、第１現像器５Ｍにより第１色（マゼンタ）のトナー
が静電潜像に応じて感光ドラム１に付与される。この
際、第２、第３、第４現像器５Ｃ、５Ｙ、５Ｂは、作動
オフしており、第１色のトナー像は第２、第３、第４現
像器５Ｃ、５Ｙ、５Ｂに影響を受けることなく、中間転
写体である中間転写ローラ６と感光ドラム１のなす転写
ニップ部に到達し、中間転写ローラ６のパイプ状芯金６
ａに印加された第１色のトナーと逆極性の電圧７ａによ
って、転写ニップ部域に形成された電界により第１色の
トナー像は、中間転写ローラ６上に中間転写される。第
１色のトナー像の転写を終えた感光ドラム１の表面は、
クリーニング装置９により表面を清掃された後、第２色
（シアン）の画像形成工程に入る。第２色目の工程にお
いては、第２現像器５Ｃのみが作動し、他の現像器５
Ｍ、５Ｙ、５Ｂは作動オフしており、以下、上述した手
順と同様の手順によって、第２色のトナー像が中間転写
ローラ６上に中間転写される。以下、第３色（イエロ
ー）、第４色（ブラック）が中間転写ローラ６上に順次
中間転写され、中間転写ローラ６上に４色の重ね合わせ
カラー画像が形成される。In FIG. 3, a photosensitive drum (image carrier)
1 rotates in the direction of arrow R1 and is uniformly charged by the primary charging roller 2, and after an electrostatic latent image is formed by exposure 3, the toner of the first color (magenta) is discharged by the first developing device 5M. It is applied to the photosensitive drum 1 according to the electrostatic latent image. At this time, the second, third, and fourth developing units 5C, 5Y, and 5B are off, and the toner image of the first color affects the second, third, and fourth developing units 5C, 5Y, and 5B. Without reaching the transfer nip portion formed by the photosensitive drum 1 and the intermediate transfer roller 6 as an intermediate transfer member, the pipe-shaped core metal 6 of the intermediate transfer roller 6
The toner image of the first color is intermediately transferred onto the intermediate transfer roller 6 by the electric field formed in the transfer nip area by the voltage 7a having a polarity opposite to that of the toner of the first color applied to a. The surface of the photosensitive drum 1 after the transfer of the toner image of the first color is
After the surface is cleaned by the cleaning device 9, the second color (cyan) image forming process is started. In the second color process, only the second developing device 5C operates and the other developing devices 5C
M, 5Y, and 5B are off, and the second color toner image is intermediately transferred onto the intermediate transfer roller 6 by the same procedure as described above. Thereafter, the third color (yellow) and the fourth color (black) are sequentially intermediate-transferred onto the intermediate transfer roller 6, and a four-color superimposed color image is formed on the intermediate transfer roller 6.

【０００７】次に、カセット１０より転写材Ｐが１枚、
給紙ローラ１１により取り出され、転写ガイド１２を経
て、感光ドラム１と中間転写体である中間転写ローラ６
の転写ニップ部域に挿通される。このとき、中間転写ロ
ーラ６の芯金６ａにトナーと同極性の電圧７ａが印加さ
れ、転写材Ｐ上に中間転写ローラ６上に第１〜第４色の
トナー像が転写される。Next, one transfer material P from the cassette 10
The sheet is taken out by a sheet feeding roller 11, passed through a transfer guide 12, and then the photosensitive drum 1 and an intermediate transfer roller 6 which is an intermediate transfer member.
Of the transfer nip. At this time, a voltage 7a having the same polarity as the toner is applied to the core metal 6a of the intermediate transfer roller 6, and the toner images of the first to fourth colors are transferred onto the transfer material P onto the intermediate transfer roller 6.

【０００８】図４は、中間転写ローラ６に中間転写され
たトナー像が転写材Ｐに転写されるようすを示すもので
ある。FIG. 4 shows how the toner image intermediately transferred to the intermediate transfer roller 6 is transferred to the transfer material P.

【０００９】転写ニップ部域を出た未定着カラー像を載
せた転写材Ｐは、搬送ガイド１３を経て定着器１５に到
達し、加熱加圧されて永久定着画像が得られる。The transfer material P, which has left the unfixed color image and has left the transfer nip area, reaches the fixing device 15 via the transport guide 13 and is heated and pressed to obtain a permanently fixed image.

【００１０】転写材Ｐへのトナー像転写終了後に、中間
転写ローラ６の芯金６ａにはトナーと同極性のクリーニ
ングバイアス電圧７ａが印加され、中間転写ローラ６上
の転写残りトナーは感光ドラム１に戻され、クリーニン
グ装置９に回収される。After the transfer of the toner image onto the transfer material P, a cleaning bias voltage 7a having the same polarity as the toner is applied to the core metal 6a of the intermediate transfer roller 6, and the transfer residual toner on the intermediate transfer roller 6 is the photosensitive drum 1. And is collected in the cleaning device 9.

【００１１】中間転写体である中間転写ローラ６は、パ
イプ上の芯金６ａの上に、シリコーンゴム、テフロンゴ
ム、クロロプレンゴム、ウレタンゴム、ＥＰＤＭ等より
なる弾性材ソリッド、あるいは発泡状に形成していて、
さらに、弾性材にカーボンまたは金属粉等を分散させて
抵抗調整した中抵抗弾性層６ｂを被覆したものであり、
弾性層６ｂは１０5 〜１０11Ω・cmの体積抵抗率を持
つ。中抵抗の弾性ローラを中間転写体に用いることで、
中間転写体への転写時の画像乱れを防ぎ、かつクリーニ
ングバイアスを印加することでクリーニングをすること
ができるので、クリーニング装置が不用であるなどの利
点を持つ。The intermediate transfer roller 6, which is an intermediate transfer member, is formed on the cored bar 6a on the pipe in the form of a solid elastic material made of silicone rubber, Teflon rubber, chloroprene rubber, urethane rubber, EPDM or the like, or a foamed material. And
Further, an elastic material is coated with a medium resistance elastic layer 6b in which carbon or metal powder or the like is dispersed to adjust the resistance,
The elastic layer 6b has a volume resistivity of 10 5 to 10 11 Ω · cm. By using a medium resistance elastic roller for the intermediate transfer body,
Since the image can be prevented from being disturbed at the time of transfer to the intermediate transfer member and cleaning can be performed by applying the cleaning bias, there is an advantage that a cleaning device is unnecessary.

【００１２】[0012]

【発明が解決しようとする課題】しかしながら、上述の
従来技術のように、中抵抗弾性ローラによる中間転写ロ
ーラ６を用いた場合、製造時における抵抗制御が難し
く、１本のローラ内においても不均一な抵抗分布を有す
る場合が生じる。一方感光ドラム１は、製造時における
感光層の厚さのムラや、耐久による削れムラなどによ
り、やはり部分的な電位ムラを生じることがある。この
ような場合、ハーフトーン画像の微妙なムラとなって、
画像上に現れる場合があるが、中間転写ローラ６と、感
光ドラム１のムラが重なると、周期性のない濃度ムラが
発生し、この結果、カラー画像においてはＣ、Ｍ、Ｙ、
Ｂの画像のハーフトーン画像における上記濃淡ムラが異
なる位置にずれて生じるため、最終的にその部分の色味
が変わってしまって、単なる濃さの変化以上に著しい画
質の劣化を招くおそれがある。However, when the intermediate transfer roller 6 of the medium resistance elastic roller is used as in the above-mentioned conventional technique, it is difficult to control the resistance at the time of manufacturing, and the unevenness is caused even in one roller. There are cases where the resistance distribution is different. On the other hand, the photosensitive drum 1 may still have partial potential unevenness due to unevenness of the thickness of the photosensitive layer at the time of manufacture, scraping unevenness due to durability, and the like. In such a case, there will be subtle unevenness in the halftone image,
Although it may appear on the image, when the unevenness of the intermediate transfer roller 6 and the photosensitive drum 1 overlap, density unevenness having no periodicity occurs, and as a result, C, M, Y, and
Since the unevenness of light and shade in the halftone image of the image of B occurs at different positions, the tint of that portion may be changed eventually, which may cause a remarkable deterioration in image quality beyond a simple change in darkness. .

【００１３】[0013]

【課題を解決するための手段】本発明は、上述事情に鑑
みてなされたものであって、回転可能な画像担持体上に
形成したトナー像を、該画像担持体との間に転写ニップ
部を形成する中抵抗の弾性体からなる中間転写ローラ上
に中間転写し、さらに該中間転写ローラ上のトナー像を
転写材上に最終転写してなる画像形成装置において、前
記画像担持体の単位時間当たりの回転数と、前記中間転
写ローラの単位時間当たりの回転数とについて、一方が
他方の整数倍となるように設定する、ことを特徴とす
る。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a toner image formed on a rotatable image carrier is transferred to a transfer nip portion between the toner image and the image carrier. In the image forming apparatus in which the intermediate transfer is performed on the intermediate transfer roller made of an elastic medium having a medium resistance, and the toner image on the intermediate transfer roller is finally transferred onto the transfer material, the unit time of the image carrier is The number of rotations per hit and the number of rotations per unit time of the intermediate transfer roller are set so that one is an integral multiple of the other.

【００１４】[0014]

【作用】以上構成に基づき、例えばカラー画像形成時の
部分的な色味の変化が生じるのを防止することができ
る。Based on the above construction, it is possible to prevent a partial change in tint when a color image is formed.

【００１５】[0015]

【実施例】以下、図面に沿って、本発明の実施例につい
て説明する。 〈実施例１〉図１および図２は本発明の実施例１の画像
形成装置の縦断面図であり、前出と同符号は同部材を示
す。Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIGS. 1 and 2 are longitudinal sectional views of an image forming apparatus according to Embodiment 1 of the present invention, in which the same reference numerals as those used above denote the same members.

【００１６】中間転写体である中間転写ローラ６はパイ
プ状の芯金６ａ上に、ＥＰＤＭなどよりなる弾性体に微
細カーボンまたは金属粉体を均一に分散させて、体積抵
抗率１０5 〜１０11Ω・cmに調整した厚さほぼ６ｍｍの
弾性層６ｂで被覆したものを使用している。The intermediate transfer roller 6 as an intermediate transfer member has a volume resistivity of 10 5 to 10 11 on a pipe-shaped core metal 6 a in which fine carbon or metal powder is uniformly dispersed in an elastic body made of EPDM or the like. It is coated with an elastic layer 6b having a thickness of about 6 mm adjusted to Ω · cm.

【００１７】感光ドラム１は、負極性のＯＰＣ感光ドラ
ムを用い、直径を３２ｍｍ、プロセススピードは周速１
００ｍｍ／秒とした。これに対し、中間転写ローラ６は
外周をＡ４判縦長さ２９７ｍｍよりも長くするため外径
を９６．４ｍｍとし、硬度を２８°（Ａｓｋｅｒ−Ｃ測
定法による）として、感光ドラム１に対し、総圧１００
０ｇで当接させて従動回転させた。この結果、当接部に
おける、転写ニップ部Ｎの中間転写ローラ６の外径が実
質的に９６．０ｍｍとなり（すなわち、半径４８．０ｍ
ｍとなり）、感光ドラム１の外径に対し、中間転写ロー
ラ６の外径が３倍となって、単位時間当たりの回転数で
は、転写ローラ６に対し、感光ドラム１を３倍となるよ
うに設定している。また、現像器５Ｍ、５Ｃ、５Ｙ、５
Ｂには、各々、Ｍ、Ｃ、Ｙ、Ｂ色の１成分非磁性ネガ現
像剤が用いられており、レーザ光（露光）３により露光
を受けた、感光ドラム１上の露光部分を反転現像法によ
り順次現像を行った。そして、各色のトナー像を中間転
写ローラ６上に転写するために、バイアス電圧が可変の
定電圧電源３０を用いた。The photosensitive drum 1 is a negative polarity OPC photosensitive drum, has a diameter of 32 mm and a process speed of 1 peripheral speed.
It was set to 00 mm / sec. On the other hand, the intermediate transfer roller 6 has an outer diameter of 96.4 mm in order to make the outer circumference longer than the A4 size length 297 mm, and has a hardness of 28 ° (by Asker-C measurement method), and the total length of the photosensitive drum 1 is larger than that of the photosensitive drum 1. Pressure 100
It was abutted at 0 g and driven to rotate. As a result, the outer diameter of the intermediate transfer roller 6 in the transfer nip portion N at the contact portion becomes substantially 96.0 mm (that is, the radius of 48.0 m).
Therefore, the outer diameter of the intermediate transfer roller 6 becomes 3 times the outer diameter of the photosensitive drum 1, and the photosensitive drum 1 becomes 3 times as large as the transfer roller 6 in the number of rotations per unit time. Is set to. Further, the developing devices 5M, 5C, 5Y, 5
For B, one-component non-magnetic negative developers of M, C, Y, and B colors are used, respectively, and the exposed portion on the photosensitive drum 1 exposed by the laser beam (exposure) 3 is reversely developed. Development was carried out sequentially by the method. Then, in order to transfer the toner image of each color onto the intermediate transfer roller 6, a constant voltage power source 30 having a variable bias voltage was used.

【００１８】具体的には、図１のように、感光ドラム１
上のトナー像を中間転写ローラ６に転写する際に、第１
色目には、中間転写ローラ６に電圧Ｖ0 を印加し、第２
色目にはＶ0 ＋ｇ（ｇは定数）、第３色目にはＶ0 ＋２
ｇ、第４色目にはＶ0 ＋３ｇの電圧を印加するように、
第１色から第４色のトナー像を感光ドラム１から中間転
写ローラ６に中間転写する際に順次、転写電圧をｇずつ
中間転写ローラ６に印加する転写電圧を大きくすること
で、感光ドラム１と中間転写ローラ６間に介在するトナ
ーの抵抗の増大による転写電流の低下を補正することが
でき、良好なトナー像の転写をすることができる。Specifically, as shown in FIG. 1, the photosensitive drum 1
When transferring the upper toner image to the intermediate transfer roller 6, the first
For the second color, the voltage V 0 is applied to the intermediate transfer roller 6, and the second
V 0 + g (g is a constant) for the color and V 0 +2 for the third color
g, so that a voltage of V 0 +3 g is applied to the fourth color,
When the toner images of the first to fourth colors are intermediately transferred from the photosensitive drum 1 to the intermediate transfer roller 6, the transfer voltage applied to the intermediate transfer roller 6 is sequentially increased by g. It is possible to correct the decrease in the transfer current due to the increase in the resistance of the toner interposed between the intermediate transfer roller 6 and the intermediate transfer roller 6, and it is possible to transfer a good toner image.

【００１９】そして、中間転写ローラ６上のトナー像を
転写材Ｐ上に転写する際には、図２に示すごとく、トナ
ーと同極性の電圧７ｂを印加して、転写材Ｐ上にトナー
像を一括して最終転写する。When the toner image on the intermediate transfer roller 6 is transferred onto the transfer material P, a voltage 7b having the same polarity as that of the toner is applied to transfer the toner image onto the transfer material P as shown in FIG. The final transfer is done collectively.

【００２０】実際の中間転写では、第１色目には、中間
転写ローラ６にトナーと逆極性の電圧１ｋＶを印加し、
第２色目には１．５ｋＶ、第３色目には２．０ｋＶ、第
４色目には２．５ｋＶを印加するように、１回のトナー
転写ごとに０．５ｋＶずつ中間転写ローラに印加する電
圧値を大きくすることによって、４色の多重転写を良好
に行うことができた。In the actual intermediate transfer, a voltage of 1 kV having a polarity opposite to that of the toner is applied to the intermediate transfer roller 6 for the first color,
Voltage applied to the intermediate transfer roller by 0.5 kV for each toner transfer so that 1.5 kV is applied to the second color, 2.0 kV is applied to the third color, and 2.5 kV is applied to the fourth color. By increasing the value, it was possible to favorably perform multiple transfer of four colors.

【００２１】なお、第１色目にはＶ0 、第２色目にはＶ
0 ＋ｇ、第３色目にはＶ0 ＋ｈ、第４色目にはＶ0 ＋ｉ
（ｈ、ｉは定数）というように、中間転写ローラ６に印
加する電圧の増加分を定数ｇとせずに、増加分の電圧値
の値を、それぞれトナーの抵抗値や添加物によって変化
させることにより、色ごとの適正転写電圧値を中間転写
ローラ６に印加することによって、さらに良好な多重転
写をすることが可能となる。It should be noted that V 0 is the first color and V is the second color.
0 + g, V 0 + h for the third color, V 0 + i for the fourth color
(H and i are constants), the value of the voltage value of the increase is changed according to the resistance value of the toner or the additive without increasing the voltage applied to the intermediate transfer roller 6 to the constant g. Thus, by applying the proper transfer voltage value for each color to the intermediate transfer roller 6, it becomes possible to perform more favorable multiple transfer.

【００２２】以上のようにして、中間転写ローラ６上に
形成された４色のトナー像を転写材Ｐ上に最終転写した
ところ、感光ドラム１と中間転写ローラ６の各々の有す
るムラ部分が１つの画面上においては、４色で完全に同
一の場所に生ずるようになり、従来のように各色の濃淡
ムラが、別々の場所に生じることにより、色味の変化が
生じるのを防止することができた。As described above, when the four color toner images formed on the intermediate transfer roller 6 are finally transferred onto the transfer material P, the uneven portion of each of the photosensitive drum 1 and the intermediate transfer roller 6 is 1 On four screens, four colors will be generated at exactly the same place, and it is possible to prevent changes in tint due to uneven density of each color occurring at different places as in the past. did it.

【００２３】なお、上述の実施例で、中間転写ローラ６
の感光ドラム１に対する外径比は３倍である必要はな
く、適当な整数倍としてよいのはいうまでもない。In the above embodiment, the intermediate transfer roller 6
It is needless to say that the outer diameter ratio with respect to the photosensitive drum 1 need not be 3 times, and may be an appropriate integral multiple.

【００２４】例えば、Ａ３判を縦送りするような場合、
感光ドラム１の外径を３４ｍｍ、転写ニップ部Ｎにおけ
る中間転写ローラ６の外径を１３６ｍｍなどとするとよ
い。 〈実施例２〉前述の実施例１では、転写ニップ部Ｎにお
ける感光ドラム１の外径に対し、中間転写ローラ６の外
径を整数倍した場合の例を説明したが、逆に、中間転写
ローラ６の外径に対し、感光ドラム１の外径を整数倍と
してもよい。この場合、中間転写ローラ６の外周は最大
通紙長さ以上とする必要があるため、感光ドラム１の外
周はさらに、この整数倍となる。このように構成するこ
とで感光ドラム１の寿命を延長することができる。具体
的には、感光ドラム１の外径を９６ｍｍまたは１９２ｍ
ｍ、転写ニップ部Ｎにおける中間転写ローラ６の外径を
９６ｍｍ（当接による縮みを含む）などとすればよい。 〈実施例３〉前述の実施例１または実施例２において
は、感光ドラム１と中間転写ローラ６とを当接従動回転
させる場合の説明を行ったが、図５に示すごとく、感光
ドラム１の端部にギア５１を設け、中間転写ローラ６側
のギア５２に噛合してこれを駆動するようにすれば、両
者の回転比を厳密に制御することが可能となる。For example, when feeding A3 size vertically,
The outer diameter of the photosensitive drum 1 may be 34 mm, and the outer diameter of the intermediate transfer roller 6 in the transfer nip portion N may be 136 mm. <Embodiment 2> In the above-described Embodiment 1, an example in which the outer diameter of the intermediate transfer roller 6 is an integral multiple of the outer diameter of the photosensitive drum 1 in the transfer nip portion N has been described. The outer diameter of the photosensitive drum 1 may be an integral multiple of the outer diameter of the roller 6. In this case, the outer circumference of the intermediate transfer roller 6 needs to be equal to or longer than the maximum sheet passing length, so that the outer circumference of the photosensitive drum 1 is further an integral multiple. With this configuration, the life of the photosensitive drum 1 can be extended. Specifically, the outer diameter of the photosensitive drum 1 is 96 mm or 192 m.
m, the outer diameter of the intermediate transfer roller 6 at the transfer nip portion N may be set to 96 mm (including contraction due to contact). <Embodiment 3> In the above-described Embodiment 1 or Embodiment 2, the case where the photosensitive drum 1 and the intermediate transfer roller 6 are rotated in contact with each other has been described. However, as shown in FIG. If the gear 51 is provided at the end portion and meshes with the gear 52 on the intermediate transfer roller 6 side to drive the gear 52, it is possible to strictly control the rotation ratio of the both.

【００２５】しかも、このとき、中間転写ローラ６の感
光ドラム１との転写ニップ部Ｎにおける外径を実施例１
で述べた場合よりも若干大きくしてやることで、感光ド
ラム１の周速をｖP （ｍｍ／秒）、転写ローラ６の周速
をｖT （ｍｍ／秒）、転写材Ｐの転写ニップ部Ｎにおけ
る走行速度をｖm （ｍｍ／秒）としたときに、 ｖP ＜ｖm ＜ｖT ……（１） なる関係を満たすようにすることができる。このよう
に、転写ニップ部Ｎにおいて速度差を設けることでトナ
ーの転写効率を向上させることができ、感光ドラム１か
ら中間転写ローラ６への中間転写時、および中間転写ロ
ーラ６から転写材Ｐへの最終転写時において、中抜け画
像等が生じるのを防止できる。 〈実験例１〉図１および図５において、感光ドラム１の
外径を３２．０ｍｍ、ギア５１の歯数を３２歯、中間転
写ローラ６の外径を９７．５ｍｍ、ギア５２の歯数を９
６歯とし、総圧１４００ｇで感光ドラム１と中間転写ロ
ーラ６とを当接させた。In addition, at this time, the outer diameter of the intermediate transfer roller 6 at the transfer nip portion N with the photosensitive drum 1 is set to the value in the first embodiment.
By slightly increasing the peripheral speed of the photosensitive drum 1 by v P (mm / sec), the peripheral speed of the transfer roller 6 by v T (mm / sec), and the transfer nip portion N of the transfer material P. It is possible to satisfy the relationship of v P <v m <v T (1), where v m (mm / sec) is the traveling speed in. In this way, by providing the speed difference in the transfer nip portion N, the transfer efficiency of the toner can be improved, and at the time of intermediate transfer from the photosensitive drum 1 to the intermediate transfer roller 6, and from the intermediate transfer roller 6 to the transfer material P. It is possible to prevent the occurrence of a hollow image or the like during the final transfer. <Experimental Example 1> In FIGS. 1 and 5, the outer diameter of the photosensitive drum 1 is 32.0 mm, the number of teeth of the gear 51 is 32, the outer diameter of the intermediate transfer roller 6 is 97.5 mm, and the number of teeth of the gear 52 is 9
The number of teeth is 6, and the photosensitive drum 1 and the intermediate transfer roller 6 are brought into contact with each other at a total pressure of 1400 g.

【００２６】この結果、転写ニップ部Ｎにおける中間転
写ローラ６の外径は約９７．０ｍｍとなり、前述のｖP
に対し、ｖT は約１％速くなった。これに対し、ｖm は
ｖPに対し０．５％程度速い走行速度となった。このよ
うに、感光ドラム１、中間転写ローラ６、転写材Ｐの間
に互いに速度差をつけることで、中抜けのない良好な中
間転写、および最終転写像が得られた。また、ギア５
１、５２により、感光ドラム１と中間転写ローラ６の相
対的な回転数比を厳密に規制することで、濃淡ムラによ
る色味の変化を完全に防止することができた。 〈実験例２〉図１および図５において、感光ドラム１の
外径を３２．０ｍｍ、ギア５１の歯数を３２歯、中間転
写ローラ６の外径を９６．５ｍｍ、ギア５２の歯数を９
６歯とし、感光ドラム１から中間転写ローラ６への中間
転写時には、両者を総圧２００ｇで当接させ、一方、中
間転写ローラ６から転写材Ｐへの最終転写時には両者を
総圧２０００ｇで当接させた。As a result, the outer diameter of the intermediate transfer roller 6 at the transfer nip portion N becomes about 97.0 mm, and the above-mentioned v P
In contrast, v T was about 1% faster. On the other hand, v m became a running speed about 0.5% faster than v p . In this way, by providing a speed difference among the photosensitive drum 1, the intermediate transfer roller 6, and the transfer material P, a good intermediate transfer without a void and a final transfer image were obtained. Also, gear 5
By strictly controlling the relative rotational speed ratio between the photosensitive drum 1 and the intermediate transfer roller 6 by means of Nos. 1 and 52, it was possible to completely prevent the change of the tint due to the uneven density. <Experimental Example 2> In FIGS. 1 and 5, the outer diameter of the photosensitive drum 1 is 32.0 mm, the number of teeth of the gear 51 is 32, the outer diameter of the intermediate transfer roller 6 is 96.5 mm, and the number of teeth of the gear 52 is 9
When the intermediate transfer from the photosensitive drum 1 to the intermediate transfer roller 6 is made up of 6 teeth, they are brought into contact with each other at a total pressure of 200 g, while at the time of final transfer from the intermediate transfer roller 6 to the transfer material P, both are contacted at a total pressure of 2000 g. Contacted.

【００２７】この結果、中間転写時には、転写ニップ部
Ｎにおける中間転写ローラ６の外径は約９６．３ｍｍ、
最終転写時には転写ニップ部Ｎにおける中間転写ローラ
６の外径は約９５．８ｍｍとなり、 中間転写時において、ｖP ＜ｖT ……（２） 最終転写時において、ｖT ＜ｖm ……（３） とすることができた。この結果、中間転写時には、軽圧
化と中間転写ローラ６の周速アップによる転写性の向
上、および中抜け画像の防止がより効果的に行われ、一
方、最終転写時においては、転写材Ｐを中間転写ローラ
６の周速よりも速く動かすことができることにより、転
写性を一層向上することができ、かつ、色味の変化を防
止することができた。As a result, during intermediate transfer, the outer diameter of the intermediate transfer roller 6 in the transfer nip portion N is about 96.3 mm,
At the time of final transfer, the outer diameter of the intermediate transfer roller 6 in the transfer nip portion N is about 95.8 mm, and at the time of intermediate transfer, v P <v T (2) At the time of final transfer, v T <v m ...... ( 3) was possible. As a result, during the intermediate transfer, the transferability is improved by reducing the pressure and increasing the peripheral speed of the intermediate transfer roller 6, and the hollow image is prevented more effectively. On the other hand, during the final transfer, the transfer material P is By being able to move the intermediate transfer roller 6 faster than the peripheral speed of the intermediate transfer roller 6, it was possible to further improve the transferability and prevent a change in color.

【００２８】以上の実験例では、トナー像を転写させる
側の速度を速くする場合、および、遅くする場合（実験
例１の転写材Ｐ）について説明を行ったが、どちらの場
合においても、等速時に比べ、良好な転写性が得られる
のは、物理的な摺察効果によるものと思われる。なお、
これらの効果を用いて出力する画像は、感光ドラム１上
の画像に対し、伸び、あるいはちぢみの生じる場合があ
るが、転写画像の縮尺を最適化するように必要に応じて
レーザ光３の走査速度と感光ドラム１の周速の関係を調
整すれば良いのはもちろんである。 〈実施例４〉前述の実施例１ないし実施例３において
は、最終転写時は中間転写ローラ６と感光ドラム１との
間に転写材Ｐを通して最終転写を行う場合について説明
を行ったが、感光ドラム１の代わりに、最終転写専用の
ローラを用いてもよいのはもちろんである。この場合、
構成が若干複雑となるが、実施例３で説明したような、
中間転写時に感光ドラム１と中間転写ローラ６との周速
ｖP 、ｖT 間に周速差をつけ、また、最終転写時におい
ては、中間転写ローラ６と転写材Ｐとの周速ｖTおよび
速度ｖm の間に速度差を設けるような場合、ｖP 、ｖ
T 、ｖm が独立に設定できるという利点がある。図６
は、このような構成の一例を示すもので、導電性の転写
ローラ５３の芯金５４に再転写バイアス７ｂを印加した
ものである。なお、図中でこの他の部分の前述の実施例
１における場合と同一機能を有するものには同一の符号
を付してあり、感光ドラム１と中間転写ローラ６の回転
数比は２：１に設定してある。また、最終転写時以外の
動作は前述の実施例と全く同様なので、詳細な説明は省
略する。In the above experimental examples, the case where the speed at which the toner image is transferred is increased and the case where the speed is decreased (the transfer material P of Experimental example 1) have been described, but in either case, etc. It is considered that the good transferability can be obtained as compared with the speed, because of the physical inspection effect. In addition,
An image output using these effects may be stretched or slightly staggered with respect to the image on the photosensitive drum 1, but the laser beam 3 is scanned as necessary so as to optimize the scale of the transferred image. Of course, the relationship between the speed and the peripheral speed of the photosensitive drum 1 may be adjusted. <Fourth Embodiment> In the first to third embodiments described above, the case where the final transfer is performed by passing the transfer material P between the intermediate transfer roller 6 and the photosensitive drum 1 at the time of the final transfer is described. Of course, instead of the drum 1, a roller dedicated to the final transfer may be used. in this case,
Although the configuration is slightly complicated, as described in the third embodiment,
The peripheral speed of the photosensitive drum 1 and the intermediate transfer roller 6 during intermediate transfer v P, v with a peripheral speed difference between T, also, at the time of the final transfer, the peripheral speed of the intermediate transfer roller 6 and the transfer material P v T And a velocity difference between the velocity v m and the velocity v m , v P , v
There is an advantage that T and v m can be set independently. Figure 6
Shows an example of such a configuration, in which the retransfer bias 7b is applied to the core metal 54 of the conductive transfer roller 53. In the drawing, the other parts having the same functions as those in the above-described first embodiment are designated by the same reference numerals, and the rotation speed ratio of the photosensitive drum 1 and the intermediate transfer roller 6 is 2: 1. Is set to. Further, the operation other than the final transfer is the same as that of the above-described embodiment, and thus the detailed description will be omitted.

【００２９】なお、上述の実施例１〜４においては、感
光ドラム１を用いた場合について説明を行ったが、この
代わりに感光体ベルトを用いた場合でも、本発明は同様
に実施可能である。また、露光光源はレーザ光以外のＬ
ＥＤアレイやその他の光源でもよいのはもちろん、現像
法も背景露光による正規現像法でも本発明の本質には何
ら変わりなく実施できるのはいうまでもないことであ
る。In the above-described Examples 1 to 4, the case where the photosensitive drum 1 is used has been described, but the present invention can be similarly implemented even when a photosensitive belt is used instead. . The exposure light source is L other than the laser light.
It goes without saying that an ED array or other light source may be used, and a development method or a regular development method by background exposure can be carried out without changing the essence of the present invention.

【００３０】[0030]

【発明の効果】以上、説明したように、画像担持体１の
単位時間あたりの回転数と中間転写ローラの単位時間あ
たりの回転数とを、一方が他方の整数倍となるように設
定することにより、画像担持体の厚さや感度のムラ及び
中間転写ローラの抵抗ムラにそれぞれ起因する画像の濃
淡ムラが互いに不規則に重なり合って色味が変化すると
いう不具合を有効に防止することができる。As described above, the number of rotations of the image carrier 1 per unit time and the number of rotations of the intermediate transfer roller per unit time are set so that one is an integral multiple of the other. As a result, it is possible to effectively prevent the problem that the unevenness of the image density due to the unevenness of the thickness and sensitivity of the image carrier and the unevenness of the resistance of the intermediate transfer roller are irregularly overlapped with each other to change the tint.

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

【図１】実施例１の画像形成装置において、感光ドラム
から中間転写ローラにトナー像を中間転写するようすを
示す動作説明図。FIG. 1 is an operation explanatory diagram illustrating an intermediate transfer of a toner image from a photosensitive drum to an intermediate transfer roller in an image forming apparatus according to a first exemplary embodiment.

【図２】同じく画像形成装置において、中間転写ローラ
から転写材にトナー像を最終転写するようすを示す動作
説明図。FIG. 2 is an operation explanatory diagram showing the final transfer of the toner image from the intermediate transfer roller to the transfer material in the image forming apparatus.

【図３】従来の画像形成装置の概略を示す縦断面図。FIG. 3 is a vertical sectional view showing an outline of a conventional image forming apparatus.

【図４】同じく中間転写ローラから転写材にトナー像を
転写するようすを示す拡大縦断面図。FIG. 4 is an enlarged vertical sectional view showing how the toner image is transferred from the intermediate transfer roller to the transfer material.

【図５】実施例３の感光ドラムと中間転写ローラとのギ
ヤの噛合関係を示す斜視図。FIG. 5 is a perspective view showing a gear meshing relationship between a photosensitive drum and an intermediate transfer roller according to a third exemplary embodiment.

【図６】実施例４の画像形成装置の概略を示す縦断面
図。FIG. 6 is a vertical sectional view showing an outline of an image forming apparatus according to a fourth embodiment.

【符号の説明】[Explanation of symbols]

１ 画像担持体（感光ドラム） ６ 中間転写ローラ Ｎ 転写ニップ部 Ｐ 転写材 1 image carrier (photosensitive drum) 6 intermediate transfer roller N transfer nip P transfer material

───────────────────────────────────────────────────── フロントページの続き (72)発明者 小野 和朗 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 松隈 稔 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 弓納持 貴康 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 (72)発明者 七瀧 秀夫 東京都大田区下丸子３丁目30番２号 キヤ ノン株式会社内 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuro Ono 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Minoru Matsukuma 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Takayasu Yuminochi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hideo Nanaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】 回転可能な画像担持体上に形成したトナ
ー像を、該画像担持体との間に転写ニップ部を形成する
中抵抗の弾性体からなる中間転写ローラ上に中間転写
し、さらに該中間転写ローラ上のトナー像を転写材上に
最終転写してなる画像形成装置において、 前記画像担持体の単位時間当たりの回転数と、前記中間
転写ローラの単位時間当たりの回転数とについて、一方
が他方の整数倍となるように設定する、 ことを特徴とする画像形成装置。1. A toner image formed on a rotatable image carrier is intermediately transferred onto an intermediate transfer roller made of an elastic medium having a medium resistance which forms a transfer nip portion between the image carrier and the image carrier, and In an image forming apparatus for finally transferring a toner image on the intermediate transfer roller onto a transfer material, regarding the number of rotations of the image carrier per unit time and the number of rotations of the intermediate transfer roller per unit time, An image forming apparatus characterized in that one is set to be an integral multiple of the other.
JP4361256A 1992-12-30 1992-12-30 Image forming device Pending JPH06202492A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4361256A JPH06202492A (en) 1992-12-30 1992-12-30 Image forming device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4361256A JPH06202492A (en) 1992-12-30 1992-12-30 Image forming device

Publications (1)

Publication Number Publication Date
JPH06202492A true JPH06202492A (en) 1994-07-22

Family

ID=18472835

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4361256A Pending JPH06202492A (en) 1992-12-30 1992-12-30 Image forming device

Country Status (1)

Country Link
JP (1) JPH06202492A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0934319A (en) * 1995-07-24 1997-02-07 Canon Inc Picture forming device
JP2005145700A (en) * 2003-11-19 2005-06-09 Fuji Xerox Co Ltd Image forming device, controller, control method, and control program

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0934319A (en) * 1995-07-24 1997-02-07 Canon Inc Picture forming device
JP2005145700A (en) * 2003-11-19 2005-06-09 Fuji Xerox Co Ltd Image forming device, controller, control method, and control program

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