JP2004264774A - Conductive intermediate transfer rubber belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a conductive intermediate transfer belt in short time by simplifying a manufacturing process and also to prevent the occurrences of color slippage and inside void by reducing modulus of permanent set by increasing stress at the time of low elongation which is the required characteristic of a product. <P>SOLUTION: The conductive intermediate transfer belt 10 is constituted by mixing a resin, short fibers and a conductive material or a semiconductive material in rubber compound and the modulus of permanent set is ≤7%. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００３７】
本発明において、前記導電性転写ベルトは、請求項１０記載のようにプレス成型を溶剤を用いることなく行うことができる。これは、上述したように、導電性転写ベルトを構成するゴム層の加工性が良いからである。
【００３８】
以下、本発明に係るエンドレス状の導電性中間転写ベルトの構造及び製造方法について説明する。
１）図１に示すように単層構造の導電性中間転写ベルトの場合：
図１の中間転写ベルト１０は、ゴムに樹脂、短繊維及び導電性材料等を配合してなるゴムコンパウンドを所定の厚さ、寸法にして得られるエンドレス状（環状）のゴム層１１のみからなるベルトを示す。この中間転写ベルトは、図６（Ａ），（Ｂ）のプレス金型１２を用いて製造される。プレス金型１２は、ドラム芯金１３と、このドラム芯金１３の内側でかつ幅方向に夫々配置されて該ドラム芯金１３を支持するドラム芯金受け１４と、前記ドラム芯金１３及びドラム芯金受け１４の外側に配置された一対の上部用割型１５ａ，下部用割型１５ｂとから構成されている。但し、図６（Ａ）はプレス金型の断面図、図６（Ｂ）は図６（Ａ）のＸ矢視図を示す。
【００３９】
まず、混練り後のゴムコンパウンドをカレンダーロールで所定の厚さにゴムシートに分出しする。次に、分出ししたゴムシートを所定の寸法に切断する。つづいて、図６のプレス金型１２の一構成であるドラム芯金１３に所定の寸法に切断した前記ゴムシートを巻きつける。
【００４０】
次に、プレス金型１２のドラム芯金受け１４を図６（Ａ）のようにセットした後、ドラム芯金１３の上下に夫々上部用割型１５ａ，下部用割型１５ｂを配置する。つづいて、プレス金型１２を例えば１５０℃で１０分間、５０ｋｇ／ｃｍ^２の圧力でプレス成型する。
【００４１】
次に、プレス後、脱型してエンドレスのゴムベルト１６を作成する。つづいて、このゴムベルト１６を研磨機で０．３ｍｍ厚さまで研磨する。更に、研磨したゴムベルト１６の両端を所定の寸法にカットして導電性中間転写ベルト１０を製造する。
【００４２】
２）図２に示すように２層構造の導電性中間転写ベルトの場合：
図１の中間転写ベルト２０は、ゴム層１１の表面にゴム弾性層１７を形成した２層構造のエンドレス状のベルト構造となっている。
【００４３】
まず、下記表２に示す組成のゴム混合物を混練りし、所定の厚さにカレンダーロールで分出してシートを準備する。次に、上記１）で得られた研磨後のゴムベルトの上に前記シートを巻き、さらにセットする。つづいて、図６のプレス金型１２を１５０℃で１０分間、５０ｋｇ／ｃｍ^２の圧力でプレス成型する。
【００４４】
次に、プレス後、脱型してゴム層１１とゴム弾性層１７からなる２層構成のエンドレスベルトを作成する。つづいて、このエンドレスベルトを研磨機で０．５ｍｍ厚さまで研磨する。更に、研磨したエンドレスベルトの両端を所定の寸法にカットして体積抵抗値３×１０^１１Ω・ｃｍの導電性中間転写ベルト２０を製造する。
【００４５】
【表２】

【００４６】
３）図３に示すように３層構造の導電性中間転写ベルトの場合：
図３の中間転写ベルト３０は、ゴム層１１の表面にゴム弾性層１７、トナー離型層１８を順次形成した３層構造のエンドレス状のベルト構造となっている。
この中間転写ベルト３０は、上記２）で得られた２層構造のエンドレスベルトにトナー離型剤として、水溶性ナイロン（日本ピーケミカル製）をスプレーガンを使用して８μｍの厚さにコートし、乾燥した後、１５０℃で３０分間オーブン中で焼結硬化させることにより、製造する。
【００４７】
【実施例】
以下、本発明の各実施例１〜５、比較例１〜４及び参考例について説明する。
各実施例１〜４、比較例１〜６及び参考例における各組成は下記表３に示すとおりである。下記表３には、混練り加工性、プレス成型性、伸び１％，５％時の応力、永久伸び、印刷画像評価についても示した。なお、永久伸びのテスト条件は、表３の下欄に開示したように、テストピース厚さ０．３ｍｍ、幅１０ｍｍとし、条件を２３℃−５５％（室温），重り５ｋｇ，９６時間とした。
【００４８】
また、原料ゴム材としては、ＮＢＲ（商品名：ゼオン２３０Ｓ、日本ゼオン製）、加硫助剤として酸化亜鉛２種、加硫剤として硫黄、加硫促進剤として商品名：ノクセラーＤＭ−Ｐ（大内新興製）、老化防止剤として商品名：ノクラック２２４Ｓ（川口化学製）、加工助剤としてステアリン酸、可塑剤として商品名：ＤＯＰ（大八化学製）を使用し、補強剤の比較試験を行った。
【００４９】
【表３】

【００５０】
比較例１の場合、混練り、プレス成型の加工性は良好であったが、物性値として応力、永久伸び率が悪く、当然印刷画像評価も悪かった。なお、比較例１では、導電性材料としてカーボンブラック（商品名：ＨＡＦ（シースト３）、東海カーボン製）を混練り限界の１００重量部用いた。
【００５１】
比較例２の場合、混練り、プレス成型の加工性は良好であったが、物性値として応力、永久伸び率が悪く、当然印刷画像評価も悪かった。なお、比較例２では、樹脂として、住友ベークライト製の商品名：スミライトレジン１２６８７を混練り限界の１００重量部用いた。
【００５２】
比較例３の場合、混練り、プレス成型の加工性は良好であったが、物性値として応力、永久伸び率が悪く、当然印刷画像評価も悪かった。なお、比較例３では、短繊維として、コーネックス繊維の１５番手を長さ０．６ｍｍにカットした短繊維を混練り限界の３０重量部用いた。
【００５３】
比較例４、５の場合、混練り、プレス成型の加工性は良好であったが、物性値として応力、永久伸び率が悪く、当然印刷画像評価も悪かった。なお、比較例４では、カーボンブラックとしての上記ＨＡＦ、樹脂としての上記スミライトレジン１２６８７、短繊維としての上記コーネックス繊維を用いた。
【００５４】
比較例６の場合、混練り、プレス成型の加工性は良好であったが、物性値として応力、永久伸び率が悪く、当然印刷画像評価も悪かった。特に、伸び５％時の応力は３％で破断した。なお、比較例６では、カーボンブラックとしての上記ＨＡＦ、樹脂としての上記スミライトレジン１２６８７、短繊維としての上記コーネックス繊維を用いた。
【００５５】
実施例１の場合、加工性は良好であり、物性値の応力、永久伸び率も良好で印刷画像評価でも色ズレ、中ヌケ等がなく良好な画像が得られた。なお、実施例１及び下記実施例２〜４における上記ＨＡＦ、スミライトレジン１２６８７、コーネックス繊維の配合量は表１の通りである。
【００５６】
また、実施例２〜４の場合も、加工性は良好であり、物性値の応力、永久伸び率も良好で印刷画像評価でも色ズレ、中ヌケ等がなく良好な画像が得られた。
参考例では、混練り、プレス成型の加工性が悪く、またゴムベルトの成型ができず、物性試験印刷画像試験ができなかった。
【００５７】
以上の実施例より、実施例２，３，４配合の補強剤のブレンド配合が良く、カーボンブラックはＨＡＦ ５０〜１００重量部の範囲、樹脂は住みライトレジン１２６８７ ４０〜７０重量部の範囲、短繊維は２５〜３０重量部の範囲であれば、混練り加工性、プレス成型加工性を満足させ、物性値の１％伸び時の応力が２０ｋｇｆ／ｃｍ^２以上となり、５％伸び時の応力が１５０ｋｇｆ／ｃｍ^２以上となる。また、印刷画像に大きな影響を与える永久伸び率が７．０％から１．８％となり、この範囲に入ったゴムベルトは印刷画像テストも色ズレや中ヌケもなく、満足した画像が得られた。なお、印刷画像評価テストは、図５の電子写真印刷装置でテスト評価を行った。
【００５８】
【発明の効果】
以上詳述した如く本発明によれば、所定の硬度のゴムに、樹脂、短繊維、及び導電性材料叉は半導電性材料を配合した構成であるため、通常のゴム加工設備を使用でき、新たな設備を必要とせず安定的に安価なベルト成型ができ、ベルト製造での工程を簡素化、製造の短時間をなし得る。また、製品の要求特性である低伸び時の応力を大きくし、永久伸び率を小さくして色ズレや中ヌケのない安定した導電性中間転写ゴムベルトを提供できる。
【図面の簡単な説明】
【図１】本発明の一実施形態であるエンドレス状の単層構造の導電性中間転写ゴムベルトの断面図。
【図２】本発明の一実施形態であるエンドレス状の２層構造の導電性中間転写ゴムベルトの断面図。
【図３】本発明の一実施形態であるエンドレス状の３層構造の導電性中間転写ゴムベルトの断面図。
【図４】本発明の一実施形態であるエンドレス状の蛇行防止構造の導電性中間転写ゴムベルトの断面図。
【図５】図５はカラー電子写真印刷装置の説明図。
【図６】本発明に係る導電性中間転写ゴムベルトを製造するためのプレス金型の説明図。
【図７】図４の導電性転写ゴムベルトと図６のプレス金型との関係を示す説明図。
【符号の説明】
１０，２０，３０…導電性中間転写ゴムベルト、 １１…ゴム層、
１２…プレス金型、 １３…ドラム芯金、
１４…ドラム芯金受け、 １５ａ…上部用割型、
１５ｂ…下部用割型、 １６…ゴムベルト、
１７…ゴム弾性層、 １８…トナー離型層、
１９…蛇行防止用突起、 ２１…蛇行防止溝。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a conductive intermediate transfer rubber belt used for an intermediate transfer member of an electrophotographic printing apparatus such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
As is well known, a color electrophotographic printing apparatus such as a copying machine, a printer, and a facsimile has a configuration shown in FIG. In such an apparatus, a method is employed in which toner from a photoreceptor 1 of a developing device is electrostatically transferred to a photosensitive drum 2 and a conductive intermediate transfer belt 3 sequentially, and the electrostatically transferred toner is electrostatically transferred to a sheet 4. I have. Reference numerals 5a, 5b and 5c in the figure denote support rolls for supporting the belt 3, reference numeral 6 denotes a primary transfer roll for holding the belt 3 together with the drum 2, and reference numeral 7 denotes a belt 3 together with the support roll 5a. 2 shows a secondary transfer roll that holds the sheet. By the way, as the belt 3, a resin film, a thread-wound rubber belt, and a rubber belt containing a fabric are currently used.
[0003]
As a belt using a resin film, an endless belt of a polyimide resin having a high stress particularly at a low elongation and a small permanent elongation (creep) is used. However, in the case of a belt using a resin film, due to the problem of the resin composition of the polyimide, the resin is dissolved in a harmful solvent such as N-methylpyrrolidone. Need to be processed. Therefore, there are drawbacks that, together with a large amount of equipment, a large amount of time is spent for molding, and that measures for environmental contamination of the solvent are required.
[0004]
As an example of a belt using rubber, there is known a method in which a thread is used as a stopper for elongating the belt and is formed by winding the thread (Patent Document 1). This belt has a configuration in which a core formed by spirally forming woven fibers is embedded in a base layer made of an elastomer or a resin to form an intermediate transfer member. However, a belt using a yarn takes a very long time to wind the yarn around the drum, which increases the cost and is not suitable for mass production.
[0005]
Further, there is known a rubber belt obtained by using a woven fabric as an elongation stopper for the belt, applying rubber to the woven fabric, and molding an endless belt (Patent Documents 2 and 3). Patent Document 2 discloses an intermediate transfer member having one or more fiber layers and an elastic layer laminated on one or both sides of the fiber layers. Patent Literature 3 discloses an intermediate transfer belt having a core layer inside, and an intermediate transfer belt having two or more layers including an elastic layer and a coating layer in which the distance between fibers is 50 to 3000 μm. However, in the case of Patent Literatures 2 and 3, in order to make the woven fabric endless, it is necessary to make a weave, but it is very difficult to keep the woven density constant. As a result, there is a disadvantage that image unevenness occurs when an image is displayed using the intermediate transfer belt.
[0006]
Patent Literature 4 is a method for solving the drawbacks of these molding methods. That is, this method is a method in which carbon black or short fibers are mixed into rubber paste obtained by converting acrylic rubber into a paste form with a solvent such as toluene, and the solvent is blown off after molding. However, this method has a drawback in that when the rubber is formed into a paste and molded, the short fibers are unevenly dispersed, and image unevenness occurs when an image is displayed. In addition, it takes time to evaporate a solvent such as toluene on which the rubber is glued, which increases the cost and is not suitable for mass production. Furthermore, it is necessary to take measures such as fire prevention by converting the rubber into a paste form with a solvent such as toluene, and there is a problem that the equipment cost is high.
[0007]
Further, Patent Document 5 discloses an example in which short fibers are mixed in rubber. In this example, 10 to 40 parts of a conductive material cut into a length of 0.03 to 5.0 mm of a conductive short fiber made of a needle-like product of a metal oxide such as aluminum oxide and zinc oxide is mixed into a rubber compound. It was done. However, in this case, if the mixing ratio of the conductive substance is large, a problem occurs in the workability, and the mixing ratio of the short fiber expected to have the effect of preventing elongation cannot be increased. As a result, the permanent elongation of the belt becomes large, which causes a problem during use.
[0008]
[Patent Document 1]
JP-A-9-251246 (paragraph [0015] and FIG. 1)
[0009]
[Patent Document 2]
JP-A-10-232572 (paragraph [0010] and FIG. 1 etc.)
[0010]
[Patent Document 3]
JP-A-11-84901 (refer to claims)
[0011]
[Patent Document 4]
JP-A-10-48963 (paragraph [0034] etc.)
[0012]
[Patent Document 5]
Patent No. 2999684 (page 20, right column, lines 20 to 33)
[0013]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and simplifies the process of manufacturing a belt, which is the above-described problem, enables the belt to be manufactured in a short time, and increases the stress at low elongation, which is a required characteristic of the product. It is another object of the present invention to provide a stable conductive intermediate transfer rubber belt having a small permanent elongation and free from color shift and center drop.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the present invention uses an elastic rubber material having good workability to increase stress at low elongation and reduce permanent elongation (creep) to maintain characteristics close to resin. In addition, the manufacturing process is simplified to produce a conductive intermediate transfer rubber belt which can be manufactured in a short time and has good mass productivity.
[0015]
By the way, in order to improve the stress at the time of low elongation, it is necessary to fill a large amount of filler, and to further improve the stress, it is necessary to fill short fibers. However, these fillers and short fiber fillers have a problem that the kneading processability and press molding processability are significantly deteriorated. On the other hand, in the present invention, the kneading workability can be improved by the heat at the time of kneading by blending a resin with respect to the workability which is the subject, for example, kneading workability and press molding workability. In addition, in terms of press molding workability, the flow characteristics at the time of pressing with press heat (for example, 150 ° C.) are improved, thereby compensating for the drawbacks of high filling and blending of carbon black and short fibers, and at the time of low elongation after curing of the resin. The results also show good results in the improvement of the stress of the. As a result, even if a rubber material is used, it is possible to satisfy the required characteristics of high stress at low elongation and permanent elongation required for the intermediate transfer belt.
[0016]
That is, the conductive intermediate transfer rubber belt according to the present invention is obtained by blending a resin, a short fiber, a conductive material or a semiconductive material with a rubber compound, and has a permanent elongation of 7% or less. Features.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail.
In the present invention, the intermediate transfer rubber belt preferably has a stress at 1% elongation of 20 kgf / cm ² or more, and a stress at 5% elongation of 150 kgf / cm ² or more, It is best that the permanent elongation after standing at 23 ° C.-65% (room temperature) under a load of 5 kg / cm for 96 hours is 7% or less. Here, by maintaining the range of the stress, a sufficient stress can be obtained while maintaining good workability.
[0018]
In the present invention, as described in claim 4, the volume resistance value is preferably from 10 ² to 10 ¹³ Ω · cm. Here, a large amount occurs properties especially fracture phenomena must blended conductive material is less than volume resistivity of ^{10 2 Ω · cm, 10 13} Ω · cm insufficient electrostatic action exceeds the electrostatic toner This is because electricity transfer becomes impossible.
[0019]
In the present invention, examples of the rubber contained in the rubber compound include natural rubber (NR), nitrile rubber (NBR), epichlorohydrin rubber (ECO), hydrogenated nitrile rubber (HNBR), butadiene rubber (BR), and styrene. Butadiene rubber (SBR), isoprene rubber (IR), ethylene propylene rubber (EPM, EPDM), fluoro rubber (FR), silicone rubber (SiR), urethane rubber (UR), and alloys thereof.
[0020]
In the present invention, examples of the rubber compounding agent include a vulcanizing agent, a vulcanization accelerator, a co-crosslinking agent, an antioxidant, a softener, a plasticizer, a reinforcing agent, and a filler.
As the vulcanizing agent, for example, sulfur, organic sulfur-containing compounds, and organic peroxides can be used. The amount of the vulcanizing agent added to the rubber is usually preferably 0.1 to 30 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the rubber.
[0021]
Examples of the vulcanization accelerator include thiurams such as magnesia (MgO), tetramethylthiuram disulfide, tetraethylenethiuram disulfide, dithiocarbamates such as zinc dibutyldithiocarbamate, zinc diethyldithiocarbamate, and the like. Thiazoles such as 2-methylcaptobenzothiazole and N-cyclohexyl-2-benzothiazolesulfinamide, and other thioureas.
[0022]
Examples of the vulcanization aid include known fatty acids such as zinc white, metal oxide stearic acid, and oleic acid.
As the co-crosslinking agent, as a co-crosslinking agent with an organic peroxide, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, a polyfunctional methacrylate monomer, triallyl isocyanurate, a metal-containing monomer and the like are conventionally used. Are included.
[0023]
Examples of the antioxidant include imidazoles such as 2-mercaptobenzimidazole, amines such as phenyl-α-naphthylamine, NN-di-β-naphthyl-P-phenylenediamine, and phenols such as styrenated phenol. No.
[0024]
Examples of the softener include fatty acids such as stearic acid and paraffin wax.
Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, and process oil.
[0025]
Examples of the reinforcing agent include carbon black and white carbon, and other short fibers are also effective. Here, as the short fiber, for example, a length of about 0.1 to 10.0 mm, preferably 0.3 to 0.6 mm at 10 to 50 count is kneaded, and the workability and physical properties of press molding are kneaded. Balanced. The compounding amount of the reinforcing agent with respect to the rubber is preferably from 10 to 150 parts by weight, more preferably from 30 to 100 parts by weight, based on 100 parts by weight of the rubber. Here, if the amount of the reinforcing agent is less than 10 parts by weight, no physical property value is obtained, and if it exceeds 150 parts by weight, workability is poor and molding cannot be performed.
[0026]
In the present invention, as the resin, for example, a phenol resin, a thermosetting urethane resin, an epoxy resin, a thermosetting resin such as a reactive monomer, or polyvinyl chloride (PVC), polyvinyl acetate (PVA), thermoplastic resin A thermoplastic resin such as urethane is exemplified. The compounding amount of the resin with respect to the rubber is preferably from 10 to 150 parts by weight, more preferably from 30 to 100 parts by weight, based on 100 parts by weight of the rubber. Here, when the amount of the resin is less than 10 parts by weight, the workability is improved because the amount of the resin is too small, but the physical property value is deteriorated. On the other hand, if the compounding amount of the resin exceeds 150 parts by weight, the characteristics of the resin become too high and the characteristics of the rubber cannot be utilized, resulting in cracks and the like.
[0027]
In the present invention, examples of the short fibers include cotton, hemp, silk, rayon, acetate, nylon, acrylic, vinylon, vinylidene, polyester, polystyrene, polypropylene, polyimide, aramid, ceramic fibers, glass fibers, carbon fibers, and metal fibers. Is mentioned. The amount of the short fibers blended with the rubber is preferably 5 to 50 parts by weight, more preferably 10 to 30 parts by weight, based on 100 parts by weight of the rubber. Here, if the short fiber is less than 5 parts by weight, sufficient physical properties are not obtained even when combined with another reinforcing agent, and if it exceeds 50 parts by weight, workability is deteriorated and molding cannot be performed.
[0028]
In the present invention, examples of the conductive material include carbon black as an electronic conductive agent, a metal oxide, and a metal oxide subjected to conductive treatment. The amount of the conductive material to be mixed with the rubber is preferably 30 to 100 parts by weight, more preferably 30 to 70 parts by weight, based on 100 parts by weight of the rubber. Here, when the conductive material is less than 30 parts by weight, the resistance value is increased and the reinforcing effect is small. When the conductive material is more than 100 parts by weight, workability is deteriorated and molding cannot be performed.
[0029]
In the present invention, it is preferable to provide a toner release layer on the surface of the transfer belt. The reason for this is that if the toner release layer is not provided, for example, the toner adheres to only the rubber surface and the image formation is hindered. The toner release layer can be formed by, for example, applying a toner release material by a spraying method, but is not limited thereto.
Examples of the material of the toner release layer include FEUA-modified fluororesin paint (manufactured by Asahi Glass), fluorine-containing polyol-modified fluororesin paint (manufactured by Sumitomo Seika), PUDF-modified fluororesin paint (manufactured by Kansai Paint), and polyurethane-modified fluorine. Resin paint (Nippon Miractran, Nippon Bee Chemical), Acrylic modified fluororesin paint (Nippon Acheson), Phenol modified fluororesin paint (Nippon Acheson), Alkit modified fluorosilicone paint (Shin-Etsu Chemical), Acrylic modified silicone paint (Manufactured by Shin-Etsu Chemical Co., Ltd.), water-soluble nylon (manufactured by Teikoku Chemical Co., Ltd., manufactured by Nippon Bee Chemical Co., Ltd.) and N-methylmethoxylated nylon (manufactured by Teikoku Chemical Co., Ltd., manufactured by Nippon Bee Chemical Co., Ltd.).
[0030]
In the present invention, on the surface of the intermediate transfer rubber belt, a rubber elastic layer having a hardness of 10 ° to 95 ° by a JISA hardness meter is provided on the surface of the transfer belt as described in claim 6, and the volume resistance value is 10 ⁶ to 10. It is preferably ¹³ . The reason why the hardness of the rubber elastic layer is defined as described above is that if the hardness is less than 10 °, the elongation of the surface due to the nip pressure becomes large, so that the toner layer cracks. This is because the image quality is deteriorated, which causes an obstacle to image formation. The reason why the volume resistance is defined as described above is that if the resistance is less than 10 ⁶ , the current will flow too much, affecting other parts and causing a failure in image formation, and the resistance will exceed 10 ¹³ . This is because the electrostatic action becomes insufficient and the electrostatic transfer becomes impossible.
[0031]
It is preferable that a toner release layer is provided on the rubber elastic layer. The reason is to prevent contamination by toner.
[0032]
In the present invention, it is preferable to provide a wear-resistant rubber layer on the back surface of the intermediate transfer rubber belt. This is to reduce abrasion of the rubber belt when it is rotated by a roll or the like.
[0033]
In the present invention, the intermediate transfer belt itself can be formed by press molding. This is because the workability of the composition of the belt is good. Here, press molding refers to molding using a mold, and includes ordinary press molding, transfer molding, injection molding, and the like.
[0034]
In the present invention, for example, as shown in FIG. 4, it is preferable to provide a meandering prevention projection 19 on the back surface (inside) of the rubber layer 11 and on one side or both ends along the circumferential direction of the rubber layer 11. Here, FIG. 4 shows a case where the conductive intermediate transfer belt has a single-layer structure, but may have a two-layer structure or a three-layer structure. With the configuration as shown in FIG. 4, when the belt is driven by being incorporated in a color electrophotographic printing apparatus as shown in FIG. 5, the meandering of the belt can be prevented. When the belt of FIG. 4 is assembled into a press die, as shown in FIGS. 7A and 7B, the meandering prevention protrusions 19 are formed on the surface of the drum core 13 corresponding to the meandering prevention protrusions 19. The meandering preventing groove 21 that fits with the groove is formed in an annular shape. However, FIG. 7B is an enlarged view of a main part of FIG. 7A.
[0035]
In the present invention, the conductive transfer belt can be formed by press molding. However, the conductive transfer belt having the meandering preventing projections 19 can also be formed integrally with the rubber material that is the composition of the rubber layer 11. it can. In this case, the composition of the meandering preventing projection 19 is, for example, as shown in Table 1 below. The reason why the conductive transfer belt can be formed by integral molding is that the material of the rubber layer constituting the conductive transfer belt and the layer serving as the meandering prevention protrusions have good workability.
[0036]
[Table 1]

[0037]
In the present invention, the conductive transfer belt can be press-molded without using a solvent. This is because the workability of the rubber layer constituting the conductive transfer belt is good as described above.
[0038]
Hereinafter, the structure and manufacturing method of the endless conductive intermediate transfer belt according to the present invention will be described.
1) In the case of a conductive intermediate transfer belt having a single-layer structure as shown in FIG.
The intermediate transfer belt 10 shown in FIG. 1 includes only an endless (annular) rubber layer 11 obtained by setting a rubber compound obtained by mixing a resin, a short fiber, a conductive material, and the like into a predetermined thickness and size. Show the belt. This intermediate transfer belt is manufactured using the press die 12 shown in FIGS. The press mold 12 includes a drum core 13, a drum core receiver 14 that is arranged inside the drum core 13 and in the width direction and supports the drum core 13, the drum core 13 and the drum core 13. It comprises a pair of upper split dies 15a and lower split dies 15b arranged outside the cored bar receiver 14. 6 (A) is a cross-sectional view of the press die, and FIG. 6 (B) is a view as viewed in the direction of arrow X in FIG. 6 (A).
[0039]
First, the kneaded rubber compound is separated into a predetermined thickness by a calender roll into a rubber sheet. Next, the separated rubber sheet is cut into a predetermined size. Subsequently, the rubber sheet cut to a predetermined size is wound around a drum core 13 which is one configuration of the press die 12 shown in FIG.
[0040]
Next, after setting the drum core receiver 14 of the press die 12 as shown in FIG. 6A, the upper split die 15a and the lower split die 15b are arranged above and below the drum core 13, respectively. Subsequently, the press mold 12 is press-formed at a pressure of 50 kg / cm ² , for example, at 150 ° C. for 10 minutes.
[0041]
Next, after pressing, the mold is removed to form an endless rubber belt 16. Subsequently, the rubber belt 16 is polished to a thickness of 0.3 mm by a polishing machine. Further, the both ends of the polished rubber belt 16 are cut into a predetermined size to manufacture the conductive intermediate transfer belt 10.
[0042]
2) In the case of a conductive intermediate transfer belt having a two-layer structure as shown in FIG.
The intermediate transfer belt 20 of FIG. 1 has a two-layer endless belt structure in which a rubber elastic layer 17 is formed on the surface of a rubber layer 11.
[0043]
First, a rubber mixture having the composition shown in Table 2 below is kneaded, and the mixture is separated to a predetermined thickness by a calender roll to prepare a sheet. Next, the sheet is wound on the polished rubber belt obtained in the above 1) and further set. Subsequently, the press mold 12 shown in FIG. 6 is press-molded at 150 ° C. for 10 minutes at a pressure of 50 kg / cm ² .
[0044]
Next, after pressing, the mold is removed to form an endless belt having a two-layer structure including the rubber layer 11 and the rubber elastic layer 17. Subsequently, the endless belt is polished to a thickness of 0.5 mm with a polishing machine. Further, both ends of the polished endless belt are cut to a predetermined size to manufacture a conductive intermediate transfer belt 20 having a volume resistance value of 3 × 10 ¹¹ Ω · cm.
[0045]
[Table 2]

[0046]
3) In the case of a conductive intermediate transfer belt having a three-layer structure as shown in FIG.
The intermediate transfer belt 30 in FIG. 3 has a three-layer endless belt structure in which a rubber elastic layer 17 and a toner release layer 18 are sequentially formed on the surface of the rubber layer 11.
The intermediate transfer belt 30 is formed by coating a water-soluble nylon (manufactured by Nippon Pea Chemical Co., Ltd.) as a toner release agent on the two-layer endless belt obtained in the above 2) to a thickness of 8 μm using a spray gun. After drying, it is manufactured by sintering and curing in an oven at 150 ° C. for 30 minutes.
[0047]
【Example】
Hereinafter, Examples 1 to 5, Comparative Examples 1 to 4, and Reference Examples of the present invention will be described.
Each composition in each of Examples 1 to 4, Comparative Examples 1 to 6, and Reference Example is as shown in Table 3 below. Table 3 below also shows the kneading workability, press moldability, stress at 1% and 5% elongation, permanent elongation, and print image evaluation. As disclosed in the lower column of Table 3, the test conditions for permanent elongation were a test piece thickness of 0.3 mm and a width of 10 mm, and the conditions were 23 ° C.-55% (room temperature), a weight of 5 kg, and 96 hours. .
[0048]
The raw rubber material is NBR (trade name: Zeon 230S, manufactured by Zeon Corporation), two kinds of zinc oxide as vulcanization aids, sulfur as a vulcanizing agent, and trade name: Noxeller DM-P as a vulcanization accelerator ( Ouchi Shinko), Nocrack 224S (produced by Kawaguchi Chemical) as an anti-aging agent, stearic acid as a processing aid, trade name: DOP (produced by Daihachi Chemical) as a plasticizer, comparative test of reinforcing agents Was done.
[0049]
[Table 3]

[0050]
In the case of Comparative Example 1, the workability of kneading and press molding was good, but the stress and permanent elongation were poor in physical properties, and the printed image evaluation was naturally poor. In Comparative Example 1, carbon black (trade name: HAF (Seast 3), manufactured by Tokai Carbon Co., Ltd.) was used as a conductive material at a kneading limit of 100 parts by weight.
[0051]
In the case of Comparative Example 2, the workability of kneading and press molding was good, but the stress and permanent elongation as physical properties were poor, and the printed image evaluation was naturally poor. In Comparative Example 2, 100 parts by weight of the kneading limit was used as the resin, Sumitomo Bakelite's trade name: Sumilite Resin 12687.
[0052]
In the case of Comparative Example 3, the workability of kneading and press molding was good, but the stress and permanent elongation as physical properties were poor, and the printed image evaluation was naturally poor. In Comparative Example 3, as the short fiber, a short fiber obtained by cutting the 15th count of the Conex fiber to a length of 0.6 mm was used at a kneading limit of 30 parts by weight.
[0053]
In the case of Comparative Examples 4 and 5, the workability of kneading and press molding was good, but the stress and permanent elongation were poor in physical properties, and the printed image evaluation was naturally poor. In Comparative Example 4, the HAF as the carbon black, the Sumilite resin 12687 as the resin, and the Conex fiber as the short fiber were used.
[0054]
In the case of Comparative Example 6, the workability of kneading and press molding was good, but the stress and permanent elongation were poor physical property values, and the printed image evaluation was naturally poor. In particular, when the elongation was 5%, the stress was broken at 3%. In Comparative Example 6, the HAF as the carbon black, the Sumilite resin 12687 as the resin, and the Conex fiber as the short fiber were used.
[0055]
In the case of Example 1, the workability was good, the stress of the physical property value and the permanent elongation were also good, and a good image was obtained without any color shift, center drop, etc. even in the printed image evaluation. Table 1 shows the amounts of the HAF, Sumilite resin 12687, and Conex fiber in Example 1 and Examples 2 to 4 described below.
[0056]
Also, in the case of Examples 2 to 4, the workability was good, the stress of the physical property value and the permanent elongation were also good, and a good image was obtained without any color shift, center drop, etc. even in the printed image evaluation.
In the reference example, the workability of kneading and press molding was poor, the rubber belt could not be molded, and the physical property test and the print image test could not be performed.
[0057]
From the above examples, the blending ratio of the reinforcing agents of Examples 2, 3 and 4 is good, the carbon black is in the range of 50 to 100 parts by weight of HAF, and the resin is in the range of 40 to 70 parts by weight of Sumitomo Light Resin 12687. If the fiber is in the range of 25 to 30 parts by weight, the kneading workability and the press forming workability are satisfied, and the stress at 1% elongation of the physical property value is 20 kgf / cm ² or more, and the stress at 5% elongation is It becomes 150 kgf / cm ² or more. Further, the permanent elongation, which greatly affects the printed image, was changed from 7.0% to 1.8%, and the rubber belt falling within this range did not undergo any printed image test, no color misregistration, and no missing, and a satisfactory image was obtained. . The print image evaluation test was performed by using the electrophotographic printing apparatus shown in FIG.
[0058]
【The invention's effect】
As described above in detail, according to the present invention, a rubber having a predetermined hardness, a resin, a short fiber, and a configuration in which a conductive material or a semiconductive material is blended, so that ordinary rubber processing equipment can be used, Inexpensive belt molding can be performed stably without the need for new equipment, the belt manufacturing process can be simplified, and the manufacturing time can be shortened. In addition, it is possible to provide a stable conductive intermediate transfer rubber belt free from color misregistration and center drop by increasing the stress at low elongation, which is a required characteristic of the product, and reducing the permanent elongation.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a conductive intermediate transfer rubber belt having an endless single-layer structure according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a conductive intermediate transfer rubber belt having an endless two-layer structure according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view of an endless three-layer conductive intermediate transfer rubber belt according to an embodiment of the present invention.
FIG. 4 is a sectional view of a conductive intermediate transfer rubber belt having an endless meandering preventing structure according to an embodiment of the present invention.
FIG. 5 is an explanatory diagram of a color electrophotographic printing apparatus.
FIG. 6 is an explanatory view of a press die for producing the conductive intermediate transfer rubber belt according to the present invention.
FIG. 7 is an explanatory view showing a relationship between the conductive transfer rubber belt of FIG. 4 and a press die of FIG. 6;
[Explanation of symbols]
10, 20, 30 ... conductive intermediate transfer rubber belt, 11 ... rubber layer,
12: Press mold, 13: Drum core,
14: Drum core receiver, 15a: Split mold for upper part,
15b: Split mold for lower part, 16: Rubber belt,
17: rubber elastic layer, 18: toner release layer,
19: meandering prevention protrusion, 21: meandering prevention groove.

Claims (13)

A conductive intermediate transfer belt comprising a rubber compound, a resin, a short fiber, a conductive material or a semiconductive material, and having a permanent elongation of 7% or less. 2. The conductive intermediate transfer belt according to claim 1, wherein the belt has a JISA hardness of 90 to 100 degrees. 3. The conductive intermediate transfer rubber belt according to claim 1, wherein a stress at 1% elongation is 20 kgf / cm ² or more, and a stress at 5% elongation is 150 kgf / cm ² or more. The conductive intermediate transfer rubber belt according to any one of claims 1 to 3, wherein a volume resistance value is 10 ² to 10 ¹³ Ω · cm. 5. The conductive intermediate transfer rubber belt according to claim 1, wherein a toner release layer is provided on the surface. The conductive intermediate transfer rubber belt according to any one of claims 1 to 3, wherein a rubber elastic layer having a hardness of 10 ° to 95 ° according to a JISA hardness meter is provided on the surface, and a volume resistance value is 10 ⁶ to 10 ^13. . 7. The conductive intermediate transfer rubber belt according to claim 6, wherein a toner release layer is provided on the rubber elastic layer. 8. The conductive intermediate transfer rubber belt according to claim 1, wherein a wear-resistant rubber layer is provided on a back surface. 7. The conductive intermediate transfer rubber belt according to claim 1, wherein the belt itself is formed by press molding. The conductive intermediate transfer rubber belt according to any one of claims 1 to 4, wherein the meandering prevention protrusion is formed on the back surface by press molding. 7. The conductive intermediate transfer rubber belt according to claim 1, wherein the belt itself is formed without a solvent. 2. The conductive intermediate transfer rubber belt according to claim 1, wherein the resin is a thermosetting resin selected from a phenol resin, a thermosetting urethane resin, and an epoxy resin. 2. The conductive intermediate transfer rubber belt according to claim 1, wherein the resin is any one of a polyvinyl chloride resin, a polyvinyl acetate resin, and a thermoplastic urethane resin.

Images