JP2002363300A - Semiconductive belt or roller, and method for producing them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductive belt or a roller with which volume resistivity or surface resistivity can stably be controlled within a desired region and unevenness of the volume resistivity or the surface resistivity is not caused in any place and a method for producing the belt and the roller. SOLUTION: The semiconductive belt or the roller has a semiconductive resin layer formed from a resin composition comprising an electroconductive polymer having thiophene ring in the main chain and a heat-resistant resin in a weight ratio within the range of (2:98) to (45:55), in the semiconductive belt or the roller formed from the semiconductive resin layer or having a structure in which the semiconductive resin layer is formed on a substrate. The method for producing the belt and the roller is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive belt or roller suitable as a semiconductive member used in an electrophotographic image forming apparatus, and more particularly to a conductive belt or roller having a thiophene ring in a main chain. The present invention relates to a semiconductive belt or roller having a semiconductive resin layer formed from a resin composition containing a conductive polymer and a heat resistant resin.

[0002] The semiconductive belt or roller of the present invention comprises:
Although it is suitable as a semiconductive member such as a transfer belt of an image forming apparatus, it can also be used as an industrial transport belt or roller. In the present invention, semiconductivity means an intermediate volume resistivity between a conductor such as a metal and an insulator such as an insulating resin.

[0003]

2. Description of the Related Art Electrophotographic and electrostatic recording type copying machines,
2. Description of the Related Art In an image forming apparatus such as a facsimile or a laser beam printer, an image is formed through respective processes such as charging, exposure, development, transfer, fixing, and static elimination. In each of these steps, it is necessary to precisely control static electricity. Therefore, in such an image forming apparatus, for example,
Conductive members such as a charging belt, a charging roller, a transfer belt, and a transfer roller are provided.

[0004] Specifically, as a method of charging the surface of a photoreceptor, in a method using a conventional corona charging device, in order to generate ozone, a charging belt or a roller to which a voltage is applied is brought into contact with the photoreceptor, and the photoreceptor is charged. A method has been developed in which a surface is directly charged to be charged.

In the transfer step, instead of the transfer method using corona discharge, a transfer belt or roller is pressed against the photoreceptor from the back surface of the transfer paper and a bias voltage is applied to the transfer belt or roller to form a transfer electric field. A method has been developed in which a toner image on the surface of a photoreceptor is transferred onto transfer paper by Coulomb force. For full-color printing, a method has also been developed in which four color toners are temporarily superimposed on the intermediate transfer belt from the photoconductor and transferred once, and then collectively transferred onto transfer paper.

[0006] In such an image forming apparatus, members such as a belt and a roller are required to have at least a surface layer having appropriate conductivity. The conductive range is often a semiconductive region. In order to form a semiconductive member such as a semiconductive belt or a roller, a conductive resin composition in which an antistatic agent such as a conductive filler or a surfactant is mixed into an insulating synthetic resin is generally used. ing.

In the case of a semiconductive roller, a semiconductive resin composition is coated on a roller base such as a core metal directly or via a rubber layer or the like, or formed from the conductive resin composition. A semiconductive resin layer is formed by covering the tube.

In the case of a semiconductive belt, a seamless belt is formed from a semiconductive resin composition, or a semiconductive resin composition is coated on a belt base made of a metal or a heat-resistant resin. A sheet or a seamless belt formed from the conductive resin composition is attached to form a multilayer belt. The seamless belt formed of the semiconductive resin composition includes only the semiconductive resin layer, and is also called an endless belt or a seamless tube.

[0009] Semiconductive members such as semiconductive belts and rollers used in the image forming apparatus include (1) a volume resistivity and / or a surface resistivity of a desired semiconductive region according to each application. (2) the distribution of volume resistivity and / or surface resistivity is uniform, and (3) the volume resistivity and / or surface resistivity also vary with environmental conditions such as temperature and humidity. It is required that it does not change much, (4) it does not contaminate other members such as the photoconductor, and (5) it has excellent mechanical strength, flexibility, flexibility, workability, etc. of the semiconductive resin layer. I have.

However, a conventional method for producing a semiconductive member such as a semiconductive belt or a roller using a semiconductive resin composition obtained by kneading a conductive filler or a surfactant into an insulating synthetic resin. Then, there was a problem that the above-mentioned various properties could not be sufficiently satisfied.

Conductive fillers such as conductive carbon black tend to cause an increase in viscosity and poor dispersion when kneaded with a synthetic resin, and it is difficult to uniformly disperse them. The non-uniform dispersion of the conductive filler causes variations in the surface resistivity of the semiconductive member depending on the location.

Further, a semiconductive member formed from a semiconductive resin composition containing a conductive filler tends to fluctuate in volume resistivity and surface resistivity during use. In order to make the volume resistivity and the surface resistivity uniform and stable, it is necessary to increase the amount of the conductive filler. However, when the compounding amount of the conductive filler is increased, the flexibility, flexibility, mechanical strength, and the like of the semiconductive member are easily damaged.

In addition, when a conductive filler is blended with an insulating synthetic resin, there is a problem that the volume resistivity and the surface resistivity of the semiconductive member are apt to fluctuate rapidly depending on the blending amount of the conductive filler. If the amount of the conductive filler is small, the conductive filler is dispersed separately in the resin composition, so that it is difficult to lower the volume resistivity and the surface resistivity of the molded product to the semiconductive region. On the other hand, when the blending amount of the conductive filler is increased, the conductive filler becomes a dispersed state in the resin composition, and the volume resistivity and the surface resistivity of the molded product rapidly decrease.

As described above, since the volume resistivity and the surface resistivity of the semiconductive resin composition mainly depend on the dispersion state of the conductive filler, the semiconductive resin having a desired volume resistivity or surface resistivity is obtained. It is difficult to stably produce a conductive member. In addition, a semiconductive member formed from a semiconductive resin composition containing a conductive filler, when the temperature or humidity changes, the volume resistivity and the surface resistivity easily fluctuate greatly, and in a high temperature and high humidity environment, In particular, the tendency is remarkable. Further, the semiconductive member has a large change in volume resistivity and surface resistivity accompanying a change in voltage.

A semiconductive member formed from a resin composition in which an antistatic agent such as a surfactant is kneaded in an insulating synthetic resin has a volume resistivity and a surface resistivity which change with changes in environment such as temperature and humidity. The resistivity tends to fluctuate greatly. In addition, an antistatic agent such as a surfactant bleeds on the surface of the semiconductive member and easily contaminates other members.

There is also a method of applying an antistatic agent to the surface of a synthetic resin belt or roller. However, the antistatic agent is easily removed, and the antistatic agent contaminates other members.
Even if a rubber material is used instead of the synthetic resin, the same problem as in the case of the semiconductive resin composition occurs in the method of kneading the conductive filler and the antistatic agent.

In an image forming apparatus such as an electrophotographic system, if the volume resistivity or the surface resistivity of a conductive member such as a semiconductive belt or a roller varies from place to place or if the environment dependency is large, uniform charging may occur. And transfer becomes impossible, causing image unevenness and image quality deterioration.

In an image forming apparatus such as an electrophotographic system, each member is usually used in a high temperature environment because the fixing temperature of toner is high. Further, the image forming apparatus is often used in a high-temperature and high-humidity environment depending on the weather. If the volume resistivity or the surface resistivity of the semiconductive belt or the roller largely fluctuates due to the change of the environmental condition, it becomes impossible to form a high quality image.

[0019]

SUMMARY OF THE INVENTION It is an object of the present invention to control the volume resistivity and the surface resistivity stably within a desired range, and to vary the volume resistivity and the surface resistivity depending on the location. It is to provide a semiconductive belt or roller without any. It is another object of the present invention to provide a semiconductive belt or roller whose volume resistivity and surface resistivity have extremely small fluctuations due to environmental changes such as temperature and humidity or voltage fluctuations.

Further, an object of the present invention is to precisely control the volume resistivity and the surface resistivity in the semiconductive region,
An object of the present invention is to provide a semiconductive belt or roller which does not contaminate other members and is suitable as a semiconductive member of an image forming apparatus. Another object of the present invention is to provide a method for producing a semiconductive belt or roller having these excellent characteristics.

As a result of intensive studies, the present inventors have conceived of forming a semiconductive resin layer of a semiconductive belt or roller using a conductive polymer having a thiophene ring in the main chain. However, since this conductive polymer has insufficient strength and self-adhesiveness, the film-forming property is insufficient, and the conductive polymer has sufficiently satisfactory durability, peeling resistance, abrasion resistance and the like. It is difficult to form a molecular layer.

Therefore, as a result of further study, a semiconductive resin layer was formed using a resin composition containing a specific amount of a conductive polymer having a thiophene ring in the main chain and a heat resistant resin in combination. However, they have found that a semiconductive belt or a roller that can achieve the intended purpose can be obtained.

A resin composition containing a combination of a conductive polymer having a thiophene ring in the main chain and a heat-resistant resin or a precursor thereof, when subjected to coating or casting in a solution state, repelling occurs, and It is difficult to form a semiconductive resin layer having a large thickness and a good appearance. Therefore, when a fluorine-based surfactant having a perfluoroalkyl group as a hydrophobic group was contained at a specific ratio in an organic solvent solution containing the resin composition, the film-forming properties were remarkably improved and satisfied. It has been found that a semiconductive resin layer having physical properties can be formed. The present invention has been completed based on these findings.

[0024]

According to the present invention, there is provided a semiconductive belt or roller formed of a semiconductive resin layer or having a structure in which a semiconductive resin layer is formed on a substrate. A resin in which a semiconductive resin layer contains a conductive polymer (A) having a thiophene ring in a main chain and a heat-resistant resin (B) in a weight ratio (A: B) of 2:98 to 45:55. A semiconductive belt or roller is provided, which is a semiconductive resin layer formed from the composition.

According to the present invention, there is provided a method for manufacturing a semiconductive belt or roller which is formed from a semiconductive resin layer or has a structure in which a semiconductive resin layer is formed on a substrate. ) The weight ratio (A: B or A: B ₁ ) of the conductive polymer (A) having a thiophene ring in the main chain and the heat-resistant resin (B) or its precursor (B ₁ ) is 2:98.
-45: 55, and further contains a fluorosurfactant (C) having a perfluoroalkyl group as a hydrophobic group in an amount of 0.01 to 5% by weight based on the total amount of the resin composition. A first step of preparing an organic solvent solution of the product, and (2) applying the organic solvent solution onto a support or a substrate, drying and, if necessary, heat-treating the conductive polymer (A). And the heat-resistant resin (B) in a weight ratio (A:
B) A method for producing a semiconductive belt or roller including a second step of forming a semiconductive resin layer made of a resin composition contained in the range of 2:98 to 45:55.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive polymer used in the present invention is a conductive polymer having a thiophene ring in a main chain,
Hereinafter, it may be referred to as “thiophene-based polymer”. Among thiophene-based polymers, polythiophene is represented by the following formula (1)

[0027]

Embedded image

A polymer having a repeating unit represented by the following formula: In the formula, x represents the degree of polymerization, and the same applies to the following formula.

The thiophene-based polymer may be a polymer formed from a thiophene derivative as long as it has a thiophene ring in the main chain. Therefore, the thiophene-based polymer has the following formula (2)

[0030]

Embedded image

And polymers having a repeating unit represented by the formula:

In the above formula (2), R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, an alkoxy group,
Alkene sulfonic acid ^{_{[- (CH) n -SO 3 -}} Na + ],
Examples include a cyclohexyl group, a phenyl group, and an alkyl-substituted phenyl group. R ¹ and R ² may combine with each other to form a saturated or unsaturated monocyclic or polycyclic ring. Examples of the monocyclic or polycyclic ring include a benzene ring, a naphthalene ring, a pyrazine ring, a dioxane ring and the like. These monocyclic or polycyclic rings may have a substituent such as an alkyl group.

The conductive polymer having a thiophene ring in the main chain is represented by the following formula (3)

[0034]

Embedded image

(Wherein R ¹ and R ² are the same as those described above), such as poly (2,5-phenylenevinylene) having a thiophene ring and a double bond in the main chain, or thiophene in the main chain. Poly (2,5-phenyleneethynylene) containing a ring and a triple bond is also exemplified.

The conductive polymer having a thiophene ring in the main chain is a π-conjugated conductive polymer having a π-electron system that extends one-dimensionally along the main chain. Thiophene polymers are
For example, (1) chemical oxidative polymerization using an oxidizing agent such as FeCl ₃ , (NH ₄ ) ₂ S ₂ O ₈ , sulfuric acid, arsenic pentafluoride, (2) electrolytic polymerization, (3) dehalogenation polymerization It can be synthesized by a condensation method, (4) Grignard coupling method, or the like. The conductivity of the thiophene-based polymer can be adjusted by doping it with various dopants.

Among these thiophene-based polymers,
It shows solubility or melting property, has excellent workability, shows high electrical conductivity, is stable to the surrounding environment, can adjust conductivity, can add functionality, and has high molecular weight From the viewpoint that a polymer is easily obtained, the formula (4)

[0038]

Embedded image

Poly (3-alkylthiophene) having a repeating unit represented by the following formula is preferred. Where n is
Although it is an integer of 1 to 30, it is preferably in the range of 4 to 22, and more preferably in the range of 6 to 12, from the viewpoint of balance of solubility, heat resistance, conductivity and the like.

When the chain length of the alkyl group of the poly (3-alkylthiophene) is too short, the solubility in an organic solvent decreases. Poly (3-alkylthiophene) having a long-chain alkyl group having a hexyl group or more is preferable because it is soluble in common organic solvents such as chloroform, tetrahydrofuran, toluene, and benzene. On the other hand, the conductivity (conductivity) decreases as the chain length of the alkyl group increases.
If the chain length of the alkyl group is too long, the melting point of the polymer decreases.

Specific examples of poly (3-alkylthiophene) include poly (3-butylthiophene) and poly (3-butylthiophene).
Hexylthiophene), poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-octadecylthiophene), poly (3-docosylthiophene) and the like. A copolymer of monomers having different alkyl groups may be used.

Poly (3-alkylthiophene) can be produced, for example, by a chemical oxidation polymerization method of 3-alkylthiophene using ferric chloride (FeCl ₃ ) in chloroform. However, according to this chemical oxidation polymerization method, poly (3-alkylthiophene) having a high degree of stereoregularity cannot be obtained.

The poly (3-alkylthiophene) can be roughly divided into polymer chains of the formula (5)

[0044]

Embedded image

Wherein R is an alkyl group, a head-to-tail bond (HT structure),
Equation (6)

[0046]

Embedded image

(Wherein R is an alkyl group) with a head-to-head bond (HH structure)
One structure is included. This microstructure has a ¹ H-N
It is analyzed by MR, ¹³ C-NMR and the like.

The above HT structure (also referred to as HT-HT structure)
Is preferably 85% or more, more preferably 90%.
Above, particularly preferably 95% or more of stereoregular poly (3
-Alkylthiophene) is expected to have less steric hindrance between alkyl groups and increase the π-conjugated plane in the main chain as compared to poly (3-alkylthiophene) in which HT and HH structures are mixed. As a result, the conductivity is improved, the environment resistance is excellent, and an extremely stable conductivity (or volume resistivity or surface resistivity) is obtained.

Stereoregular poly (3-alkylthiophene) having an HT structure is obtained, for example, by starting from 2-bromo-3-alkylthiophene as a starting material, synthesizing a Grignard reagent by a two-step reaction, and then cross-linking with a nickel catalyst. A method of performing a coupling reaction, a method of dehalogenating polycondensation of 2,5-dibromo-3-alkylthiophene using active zinc and a nickel catalyst in tetrahydrofuran [Tian-An Chen, X.Wu, and RD Rieke, J. Am. Che
m. Soc., 117, 233-244 (1995)].

The conductive polymer having a thiophene ring in the main chain is represented by the formula (7)

[0051]

Embedded image

The poly (alkylenedioxythiophene) represented by

In the formula (7), n is an integer of usually 0 to 30, preferably 0 to 21. When n = 0, it represents poly (ethylenedioxythiophene). Poly (alkylenedioxythiophene) has excellent transparency, is very stable under ordinary circumstances, and shows stable electric conductivity. Poly (alkylenedioxythiophene) can be synthesized by an electrolytic polymerization method, an oxidation polymerization method, or the like.

When the thiophene polymer used in the present invention is soluble in an organic solvent, the thiophene polymer has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of usually 5,000.
~ 500,000, preferably 6,000 ~ 300,0
00. The molecular weight distribution represented by the ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is usually 1.5 to 7, preferably about 2 to 6.

The conductive polymer having a thiophene ring in the main chain has good heat resistance, and is often 100 ° C. or higher.
Further, even at a high temperature of 150 ° C. or more, the composition exhibits stable volume resistivity. Thiophene-based polymers have low hygroscopicity, and the change in volume resistivity with a change in humidity is extremely small. In addition, a thiophene-based polymer can provide a resin composition that exhibits uniform semiconductivity without variations in volume resistivity or surface resistivity due to the density of dispersion, unlike conductive fillers such as conductive carbon black. it can.

Among conductive polymers having a thiophene ring in the main chain, poly (3-alkylthiophene) and poly (alkylenedioxythiophene) have excellent heat resistance.
It is preferable because it shows stable volume resistivity and surface resistivity. The HT-stereoregular poly (3-alkylthiophene) has an HT-HT structure that repeats regularly, and the stereoregularity causes the π-conjugation between thiophene units between molecules to be widened, which is extremely stable. Indicates volume resistivity and surface resistivity. Among poly (alkylenedioxythiophenes), poly (ethylenedioxythiophene) is preferred from the viewpoint of heat resistance and conductivity.

Poly (3-alkylthiophene) can systematically change volume resistivity and surface resistivity depending on the chain length of the alkyl group on the side chain of the thiophene ring. Poly (3
-Hexylthiophene), poly (3-octylthiophene), poly (3-dodecylthiophene), and poly (3-octadecylthiophene) in that order, the volume resistivity and the surface resistivity in the semiconductive region increase.

Therefore, depending on the chain length of the alkyl group, poly (3
-Alkylthiophene) or two or more poly (3-alkylthiophenes) having different alkyl group chain lengths
By using in combination, the volume resistivity and the surface resistivity of the resin composition can be adjusted to desired levels. Further, by forming a multi-layered semiconductive resin layer using two or more kinds of poly (3-alkylthiophenes) having different alkyl group chain lengths, a semiconductive belt having different surface resistivity between the outer surface and the inner surface. Can be obtained. For example,
In the transfer belt in the image forming apparatus, it is preferable to increase the surface resistivity of the outer surface so as to be easily charged and to lower the surface resistivity and the volume resistivity of the inner surface so that the transfer voltage from the back surface works effectively.

By adding a dopant such as diphenoquinone, p-toluenesulfonic acid, and ferric chloride at a ratio of about 0.1 to 100% by weight to the thiophene-based polymer, the volume resistivity and the surface resistivity can be reduced. Can be reduced. Examples of the dopant include those in which a polymerization catalyst such as iron p-toluenesulfonate is directly contained in a thiophene-based polymer after polymerization. Even when the same dopant is mixed in the same amount, the volume resistivity and the surface resistivity can be systematically changed depending on the chain length of the alkyl group of poly (3-alkylthiophene). As a method for doping the conductive polymer, there are gas phase doping, liquid phase doping, electrochemical doping, and the like.

Since a conductive polymer having a thiophene ring in the main chain has insufficient mechanical strength, if the conductive polymer is used in a single layer, cracks may occur during demolding during film formation,
It is easy to cause a problem in durability. When a thin film is formed by a spin coating method or a casting method on a support such as a stainless steel tube or a heat-resistant film using an organic solvent solution of the conductive polymer according to an ordinary method, the formed thin film is demolded. When cracking or tearing is easy to occur.

Further, a conductive polymer having a thiophene ring in the main chain is not a resin material having excellent adhesiveness itself.
Moreover, since the strength is low, the conductive polymer layer on the surface is easily peeled off when formed in a laminated structure or a multilayer structure. When the conductive polymer layer is thin, it is easily lost due to abrasion, and it is difficult to improve the durability even if the film is made thick.

The present invention solves the above-described problems when the conductive polymer is used alone by using a conductive polymer having a thiophene ring in the main chain and a heat-resistant resin in combination. By using a resin composition containing a conductive polymer having a thiophene ring in the main chain and a heat-resistant resin, in addition to having an appropriate volume resistivity and surface resistivity, even when formed into a thin film, A semiconductive resin layer having sufficient strength can be formed.

Even when a semiconductive resin layer is laminated on a base such as a belt base or a roller base, a sufficient adhesive strength with the base can be obtained by selecting a heat-resistant resin according to the type of the base. Can be. Since the semiconductive resin layer uses a heat-resistant resin as the matrix resin,
Sufficient strength, good wear resistance, even if the surface is rubbed and scraped little by little, the semiconductive resin layer is
Since it is uniform in the thickness direction, the resistivity does not change.

As the heat-resistant resin, a resin which does not melt or soften even when continuously used at a temperature of 150 ° C. or more and has such heat resistance that deterioration does not substantially proceed is preferable. It is preferable that the semiconductive belt or roller of the present invention is a heat-resistant resin which can exhibit high heat resistance at a continuous use temperature of 150 ° C. or higher.

Examples of the heat-resistant resin include fluororesin, polyimide (preferably condensation type wholly aromatic polyimide) resin, polyamideimide, polyether sulfone, and the like.
Polyether ketone, polyether ether ketone, polybenzimidazole, polybenzoxazole, polyphenylene sulfide, bismaleimide resin, polybutylene terephthalate, polyethylene terephthalate, polyamide, polyphenylene ether, modified polyphenylene ether, polyphenylene sulfide ketone, polyphenylene sulfide sulfone, polyether Nitrile,
Examples thereof include wholly aromatic polyester, liquid crystal polyester, polyarylate, polysulfone, polyetherimide, polyaminobismaleimide, and polymethylpentene. These heat-resistant resins can be used alone or in combination of two or more.

Among these heat-resistant resins, crystalline resins having a melting point of preferably 150 ° C. or higher, more preferably 200 ° C. or higher, and a glass transition temperature of preferably 150 ° C. or higher,
More preferably, at least one heat-resistant resin selected from the group consisting of an amorphous resin having a temperature of 170 ° C. or higher and a condensation type wholly aromatic polyimide is preferable.

Illustrative examples of the crystalline resin having a melting point of 150 ° C. or more, together with the melting point, include polytetrafluoroethylene (327 ° C.) and a tetrafluoroethylene / hexafluoropropylene / perfluoroalkoxyvinyl ether copolymer (290-300 ° C.) ), Tetrafluoroethylene / ethylene copolymer (260-270 ° C), polyvinyl fluoride (227 ° C), tetrafluoroethylene / hexafluoropropylene copolymer (253-282)
C), a fluororesin such as a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (302 to 310C); polybutylene terephthalate (224 to 22C)
8 ° C.), polyethylene terephthalate (248-260)
C) and nylon 6 (220
Polyamide resins such as nylon 66 (260-265 ° C) and nylon 46 (290 ° C); polyphenylene sulfide (280-295 ° C), polyether ether ketone (334 ° C), and wholly aromatic polyester (450 ° C). And polymethylpentene (235 ° C.).

Illustrative examples of the amorphous resin having a glass transition temperature of 150 ° C. or higher, together with the glass transition temperature, include polyamideimide (280 to 285 ° C.), polyetherimide (217 ° C.), polyphenylene ether (220 ° C.),
Polyarylate (193 ° C), polysulfone (190
C) and polyether sulfone (225 to 230 C).

Among these heat resistant resins, polyamide imide, condensed wholly aromatic polyimide, and fluororesin are particularly preferred. When the heat-resistant resin is polyamide imide or condensation type wholly aromatic polyimide, a precursor thereof can be used. For example, a condensed wholly aromatic polyimide is generally formed into a film using a solution of a polyamic acid as a precursor thereof, and then heat-treated to close the ring (imidize) to obtain a polyimide film. Also in the present invention, a solution of a resin composition is prepared using a precursor of a heat-resistant resin, a film is formed using the solution, and a heat treatment is performed to form a semiconductive resin layer. Among the heat-resistant resins, polyamideimide is particularly preferred in that the temperature required for heat treatment (curing temperature) is relatively low.

Precursors such as polyamide imide and polyimide are soluble in organic solvents such as N-methyl-2-pyrrolidone (MNP), and some are commercially available as varnishes. The conductive polymer having a thiophene ring in the main chain and the heat-resistant resin or its precursor are usually dissolved in an organic solvent and used as a solution. The conductive polymer may be dissolved in the varnish of the precursor.

The conductive polymer having a thiophene ring in the main chain can be blended as a polymer, but can be synthesized in situ from a monomer in a heat-resistant resin precursor varnish. For example, in a polyamideimide varnish, 2,3-dihydrothieno (3,4-b) (1,
4) Poly (ethylenedioxythiophene) can be synthesized by adding dioxin and a catalyst and polymerizing in situ. According to this method, a solution of the resin composition in which each resin component is uniformly dispersed is easily obtained, and as a result, a uniform semiconductive resin layer can be easily formed.

The weight ratio (A: B) between the conductive polymer (A) having a thiophene ring in the main chain and the heat-resistant resin (B) is as follows:
2:98 to 45:55, preferably 3: 9.
7 to 40:60, more preferably 5:95 to 30:70
It is. When the precursor (B ₁ ) is used as a starting material as the heat-resistant resin, the weight ratio (A: B ₁ ) between the conductive polymer (A) and the precursor (B ₁ ) falls within the above range. And finally convert the precursor to a heat resistant resin.

If the content ratio of the conductive polymer (A) is too small, it becomes difficult to adjust the volume resistivity and / or the surface resistivity to a desired semiconductive region. On the other hand, when the content ratio of the conductive polymer (A) is too large, the mechanical strength of the semiconductive resin layer tends to decrease.

As a method for forming a semiconductive resin layer comprising a resin composition containing a conductive polymer (A) having a thiophene ring in the main chain and a heat-resistant resin (B), each resin component is melted. A method of blending and melt-extruding the blend may be adopted, but an organic solvent solution in which each resin component is uniformly dissolved is prepared, and the solution is applied onto a support or a substrate by a coating method or a casting method. Alternatively, a method of casting and forming a film is preferable because a thin uniform semiconductive resin film is easily formed. The solution coating method is particularly preferable when the precursor thereof is used as a heat-resistant resin as a starting material.

However, an organic solvent solution of the conductive polymer (A) and the heat-resistant resin (B) or its precursor (B ₁ ) is placed on a support or a base such as a metal tube, a glass tube, or a resin tube. When applied, repelling occurs and it is difficult to obtain a uniform film. In the present invention, the conductive polymer (A) having a thiophene ring in the main chain and the heat-resistant resin (B) or its precursor (B ₁ ) are contained in a weight ratio of 2:98 to 45:55, Further, a fluorine-based surfactant (C) having a perfluoroalkyl group as a hydrophobic group is used in an amount of 0.0 based on the total amount of the resin composition.
An organic solvent solution of the resin composition containing 1 to 5% by weight is prepared.

By containing a fluorine-based surfactant in a specific ratio, when a solution of the resin composition is applied to a support or a substrate, repelling is prevented from occurring, and a coating layer having a uniform thickness is formed. Can be formed. Organic solvent solution
The composition is coated on a support or a substrate, dried, and optionally heat-treated, so that the conductive polymer (A) and the heat-resistant resin (B) are in a weight ratio (A: B) of 2:98 to 45. : A semiconductive resin layer made of a resin composition containing 55 is formed. When a precursor is used as a starting material for a heat-resistant resin, the precursor is cured during heat treatment and converted to a heat-resistant resin.

The fluorine-based surfactant having a perfluoroalkyl group as a hydrophobic group includes cationic, anionic and
Both amphoteric and nonionic may be used. Examples of the cationic fluorine-based surfactant include perfluoroalkyltrimethylammonium salts such as perfluoroalkyltrimethylammonium iodide.

Examples of the anionic fluorine surfactant include:
For example, perfluoroalkyl sulfonates such as ammonium perfluoroalkyl sulfonate, potassium perfluoroalkyl sulfonate, sodium perfluoroalkyl sulfonate; ammonium perfluoroalkylcarboxylate, sodium perfluoroalkylcarboxylate, etc. Perfluoroalkylcarboxylates; perfluoroalkylnaphthalenesulfonates, perfluoroalkyldiallylsulfonates, perfluoroalkylphosphates and the like.

Examples of the amphoteric fluorinated surfactant include perfluoroalkylaminosulfonic acid (perfluoroalkylbetaine). Examples of the nonionic fluorinated surfactant include perfluoroalkylethylene oxide adducts, perfluoroalkyl esters, perfluoroalkylethylene oxide adducts, perfluoroalkyl esters, perfluoroalkyl group / hydrophilic group-containing oligomers , A perfluoroalkyl group-containing oligomer, a perfluoroalkyl group
Examples include lipophilic group-containing urethanes, perfluoroalkyl oligomers, perfluoroalkylamine oxides, and perfluoroalkyl group-containing silicone ethylene oxide adducts.

However, these are only some of the specific examples of the fluorine-based surfactant, and the present invention is not limited to these. These fluorine-based surfactants can be used alone or in combination of two or more. The fluorine-based surface activity is preferably nonionic, anionic, or a mixture thereof. Among them, nonionicity is more preferable, and nonionicity having an ethylene oxide chain as a hydrophilic group is most preferable.

The fluorinated surfactant is used in an amount of 0.01 to 5% by weight, preferably 0.03 to 1% by weight, more preferably 0.05 to 0.8% by weight, based on the total amount of the resin composition. use. If the use ratio of the fluorine-based surfactant is too small,
It becomes difficult to eliminate repelling during the application of the solution, and if it is too large, repelling may occur or the physical properties of the semiconductive resin layer may be adversely affected. The fluorinated surfactant may be used as a solution in an organic solvent.

As the organic solvent for dissolving the resin composition, a solvent capable of uniformly dissolving each component is appropriately selected depending on the kind of the conductive polymer, the heat-resistant resin, and the precursor of the heat-resistant resin to be used, and The components are used in an amount sufficient to dissolve the components uniformly. Specific examples of the organic solvent include chloroform, methylene chloride, tetrahydrofuran, toluene, benzene, and mixtures thereof. The obtained solution can be formed into a film by applying a coating method, a spin coating method, a casting method, or the like.

In the case of producing a seamless belt, for example, a method of applying a solution of the resin composition on a support such as a mirror-finished stainless steel tube and evaporating the solvent by heat treatment or the like is preferable. In order to form a film having a multilayer structure of two or more layers, a method of recoating may be applied.
When a heat-resistant resin precursor is used, it is cured by heat treatment at a temperature equal to or higher than the curing temperature to be converted into a heat-resistant resin. After forming the film, the support is removed from the mold to obtain a seamless belt. Also, if a film is formed on a belt base such as a polyimide film or a roller base such as a cored bar,
A conductive belt or roller integrated with the substrate is obtained.

In the case where the semiconductive resin layer alone forms a conductive belt, the semiconductive resin layer preferably has a thickness of 30 μm to 2 mm,
More preferably, the thickness is about 50 μm to 1 mm. When the semiconductive resin layer is formed on a belt substrate or a roller substrate, the thickness is preferably about 20 μm to 1 mm, more preferably about 30 to 500 μm.

The volume resistivity of the semiconductive resin layer of the present invention measured at a temperature of 20 ° C. and a voltage of 100 V is usually 1.0 × 1
0 ^{4 to} 1.0 × 10 ¹⁶ Ωcm, preferably 1.0 × 10 ⁵
１．０1.0 × 10 ¹⁴ Ωcm.

The surface resistivity of the outer surface of the semiconductive resin layer of the present invention measured at a temperature of 20 ° C. and a voltage of 100 V is usually 1.
0 × 10 ^{5 to} 1.0 × 10 ¹⁶ Ω / □, preferably 1.0
The range is from × 10 ^{5 to} 1.0 × 10 ¹⁵ Ω / □.

The temperature of the semiconductive resin layer is 20 ° C. and the voltage is 100
The surface resistivity of the outer surface measured at V (ρs; Ω / □) and the volume resistivity measured at a temperature of 20 ° C. and a voltage of 100 V (ρv;
Ωcm) is preferably 10 or more. When a semiconductive belt is applied to a transfer belt of an image forming apparatus, the surface resistivity of the outer surface is increased so as to be easily charged, and the volume resistivity is adjusted so that a transfer voltage from the back surface works effectively. Is preferably reduced.

It is also possible to make the semiconductive resin layer a multi-layer structure, increase the surface resistivity of the outer surface, and decrease the volume resistivity and the surface resistivity of the inner surface. In this case, the volume between the outer layer and the inner layer is increased by forming the inner layer using a resin composition containing a conductive polymer having high conductivity or by increasing the content of the conductive polymer in the inner layer. The resistivity and / or surface resistivity can be adjusted.

The conductive belt or roller having a semiconductive resin layer of the present invention has a small environmental dependency of the surface resistivity. For example, when the measuring temperature is changed from 20 ° C. to 100 ° C., the measuring voltage is 10 V , 100 V, and 500 V, when measured in an environment at a temperature of 60 ° C. and a relative humidity of 90%, and when measured at a temperature of 80 ° C. and a relative humidity of 90%, the value of the surface resistivity is: Substantially the same level is maintained. Even when these environmental conditions are changed, the magnification of the maximum value to the minimum value of the surface resistivity is less than 10, often less than 3, or even 2.5.
Is less than. The volume resistivity also shows a similar level of environmental resistance.

[0090]

The present invention will be more specifically described below with reference to Synthesis Examples, Examples and Comparative Examples.

[Synthesis Example 1] Poly (ethylenedioxythio)
Synthesis of fen) 20 g of Baytron C [iron para-toluenesulfonate / 1-butanol solution (40% solution)] to 5 g of Baytron Baytron M (monomer of ethylenedioxythiophene ) manufactured by Bayer AG
To synthesize poly (ethylenedioxythiophene) (hereinafter abbreviated as “PEDT”).

The thus obtained PEDT had a weight average molecular weight (Mw) of 7,200, and a molecular weight distribution (Mw / Mw) expressed by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Mn) was 4.5. Note that the iron p-toluenesulfonate used as the oxidation polymerization catalyst also functions as a dopant.

[Synthesis Example 2] Poly (3-hexylthiophene)
500m equipped with a dropping funnel synthetic 50 ml (mL) of emissions)
Ferric chloride (FeCl ₃ ) 2 in a three-necked flask
0.0 g and chloroform (130 mL) were added and sufficiently stirred. 5.0 g of 3-hexylthiophene and 20 mL of chloroform were placed in the dropping funnel. While stirring the ferric chloride solution in the flask, the 3-hexylthiophene solution was slowly dropped from the dropping funnel. After dropping the whole amount, the reaction was further performed at room temperature for 24 hours.

After completion of the reaction, 150 m of distilled water was added to the reaction solution.
L was added and the mixture was further stirred for 2 hours. The reaction solution was transferred to an all-funnel, and the lower dark brown chloroform layer was separated. This chloroform layer was put into a mixed solution of 1 L of ethanol and 50 mL of concentrated hydrochloric acid, and stirred for 1 hour. Thereafter, the resulting dark brown precipitate was removed by filtration and washed with ethanol. This crude product was purified by reprecipitation using ethanol / chloroform, and dried to obtain 4.2 g of dark brownish powdery poly (3-hexylthiophene) (hereinafter abbreviated as “P3HT”).

The P3HT obtained as described above is, for example,
It was soluble in organic solvents such as chloroform, tetrahydrofuran, toluene and benzene. This P3H was analyzed using gel permeation chromatography (GPC).
As a result of measuring the molecular weight of T, the weight average molecular weight (Mw) in terms of polystyrene was 54,000, and the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Was 5.3.

Example 1 1 g of ethylenedioxythiophene monomer (Baytron M, Bayer) and 4 g of iron parasulfonate / 1-butanol solution (Baytron C, Bayer) were mixed. This mixture is mixed with a polyamide-imide varnish manufactured by Sanken Kako (AG2-35, solid content 35%).
In addition to 66.8 g, a mixed solution of PEDT and polyamideimide (hereinafter abbreviated as “PAI”) was prepared. To this mixed solution, NMP of a fluorine-based surfactant having a perfluoroalkyl group as a hydrophobic group (DS401, manufactured by Daikin) was added.
1.3 g of a solution (concentration: 2% by weight) was added and stirred.

The solution thus prepared was applied to an inner diameter of 22
0 mm, thickness of 2 mm, length of 300 mm, applied to the mirror-finished inner surface of a stainless steel tube, then heat-treated to volatilize the organic solvent and dried.
1 hour at 220 ° C and 1 hour at 220 ° C.
A semiconductive seamless belt having a thickness of 250 μm, a width of 250 mm, and a diameter (outer diameter) of 220 mm was obtained.

[Examples 2 to 7] Except that the mixing ratio of the ethylenedioxythiophene monomer, the iron / 1-butanol solution of paratoluenesulfonate, the fluorinated surfactant solution, and the PAI varnish in Example 1 was changed. Produced a semiconductive seamless belt in the same manner as in Example 1.

Example 8 3 g of the conductive polymer (P3HT) synthesized in Synthesis Example 2 was dissolved in 27 g of NMP to give a concentration of 1
A 0% by weight solution was prepared. The solution was mixed with a polyamide-imide varnish manufactured by Sanken Kako (AG2-35, solid content 35%) 7
In addition to 7.1 g, a mixed solution of P3HT and PAI was prepared. 1.5 g of an NMP solution (concentration: 2% by weight) of a fluorine-based surfactant (DS401 manufactured by Daikin) was added to this mixed solution.
Was added and stirred. The obtained solution was 220 mm in inner diameter,
It is applied to the mirror-finished inner surface of a stainless steel tube having a thickness of 2 mm and a length of 300 mm, and then the solvent of the container is volatilized by heat treatment and dried. Thus, a semiconductive seamless belt having a thickness of 100 μm, a width of 250 mm, and a diameter (outer diameter) of 220 mm was obtained.

[Examples 9 to 11] In Example 8, P
A semiconductive seamless belt was produced in the same manner as in Example 8, except that the mixing ratio of the NMP solution of 3HT, the NMP solution of the fluorine-based surfactant, and the PAI varnish was changed.

Comparative Example 1 A conductive carbon black (N220, manufactured by Tokai Carbon Co., Ltd.) was blended with a polyamideimide varnish (AG2-35, manufactured by Sanken Kako) so as to have a solid content ratio of 30% by weight. This varnish was applied to the inner surface of a mirror-finished stainless steel tube, the organic solvent was volatilized by heat treatment, dried, and further heat-treated at a temperature of 180 ° C. for 1 hour and at a temperature of 220 ° C. for 1 hour to form a 100 μm thick coating. .
The coating was removed from the stainless steel tube to obtain a semiconductive seamless belt made of polyamideimide. When the obtained belt was observed, an aggregate of conductive carbon black was observed.

[Comparative Example 2] PEDT synthesized in Synthesis Example 1
A seamless belt was produced in the same manner as in Example 1 using 1-butanol solution of However, heat treatment
Performed at 120 ° C. for 1 hour. However, when the obtained PEDT seamless belt was removed from the stainless steel pipe, partial tearing occurred.

[Comparative Example 3] P3HT synthesized in Synthesis Example 2
Was dissolved in NMP to prepare a solution having a concentration of 10% by weight.
Using this solution, a seamless belt was produced in the same manner as in Example 1. However, heat treatment is performed at 200 ° C for 1 hour.
Time went. However, when the obtained P3HT seamless belt was released from the stainless steel pipe, a partial break occurred.

Comparative Example 4 A seamless belt was produced in the same manner as in Example 2 except that no fluorine-based surfactant was added. However, the resulting seamless belt did not have a uniform thickness due to repelling during solution application, and had poor appearance.

Comparative Example 5 A seamless belt was produced in the same manner as in Example 2, except that the content of the fluorine-based surfactant was changed from 0.1% by weight to 10% by weight. However, the resulting seamless belt does not have a uniform thickness due to repelling during solution application,
The appearance was poor.

Comparative Example 6 A seamless belt was produced in the same manner as in Example 9 except that no fluorine-based surfactant was added. However, the resulting seamless belt did not have a uniform thickness due to repelling during solution application, and had poor appearance.

Comparative Example 7 A seamless belt was produced in the same manner as in Example 9, except that the content of the fluorine-based surfactant was changed from 0.1% by weight to 10% by weight. However, the resulting seamless belt does not have a uniform thickness due to repelling during solution application,
The appearance was poor.

(Evaluation) The surface resistivity and volume resistivity of the seamless belt (semiconductive belt) were measured using a microammeter (R8340, manufactured by Advantest). The applied voltage was set to 100 V, 500 V, and 1000 V, and the measurement was performed in a room at a temperature of 20 ° C./relative humidity (RH) of 40%. The surface resistivity was measured at a temperature of 60 ° C. and 100 ° C. on a hot plate. Separately, a semi-conductive belt is put into a thermo-hygrostat for 24 hours, and after taking it out,
Immediately, the surface resistivity and the volume resistivity were measured. The processing conditions in the thermo-hygrostat are 60 ° C / 90% RH and 80 ° C /
90% RH. Further, based on the resistivity (A) at 20 ° C./100 V, a difference between the resistivity and the resistivity (B) under each condition was calculated by log (A) −log (B). The results are shown in Tables 1 to 3.

[0109]

[Table 1]

[0110]

[Table 2]

[0111]

[Table 3]

[0112]

According to the present invention, the volume resistivity and the surface resistivity can be controlled stably within a desired range, and the semiconductivity without variation depending on the location of the volume resistivity and the surface resistivity. A flexible belt or roller, and a method of making the same are provided. Further, according to the present invention, there is provided a semiconductive belt or roller in which a change in volume resistivity or surface resistivity is extremely small even due to an environmental change such as temperature and humidity or a change in voltage.

Further, according to the present invention, the volume resistivity and the surface resistivity can be precisely controlled in the semiconductive region.
A semiconductive belt or roller is provided which does not contaminate other members and is suitable as a semiconductive member of an image forming apparatus.

The semiconductive belt or roller of the present invention comprises:
Although it is suitable as a transfer belt of an electrophotographic image forming apparatus, it can also be used for a wide range of uses as a transport belt or roller.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/02 101 G03G 15/02 101 15/16 15/16 103 103 // B29K 77:00 B29K 77: 00 81:00 81:00 C08L 101: 00 C08L 101: 00 (72) Inventor Toshihiko Takiguchi 1-3-1 Shimaya, Konohana-ku, Osaka-shi, Osaka F-term in Sumitomo Electric Industries, Ltd. Osaka Works 2H071 BA42 BA43 DA06 DA09 2H200 FA01 GB50 HA02 HA28 HB12 HB13 HB22 HB45 HB46 HB47 JA02 JA25 JA26 JA27 JB06 JB45 JB46 JB47 JC03 JC15 JC16 JC17 LC04 LC09 MA02 MA11 MA17 MA20 MB02 MB04 MB05 MC18 3A04 AA02GAA AGA14A04 AA26 AA26X AA27 AA27X AA45 AA46 AA48 AA51 AA54 AA55 AA60 AA61 AA62 AA76 AA84 AA86 AF36Y AH16 BA02 BB02 BC01 BC10 4F205 AA34 AA40 AB10 AB21 AE 03 AH04 AH12 AR06 AR20 GA06 GB02 GC01 GC06 GE24 GF24

Claims (10)

[Claims] (1) The semiconductor device is formed of a semiconductive resin layer,
Alternatively, in a semiconductive belt or roller having a structure in which a semiconductive resin layer is formed on a base, the semiconductive resin layer is formed of a conductive polymer (A) having a thiophene ring in a main chain and a heat-resistant resin ( B) and the weight ratio (A: B) 2: 98-4.
5: A semiconductive belt or roller, which is a semiconductive resin layer formed from a resin composition contained in the range of 55:55. 2. The semiconductive belt or roller according to claim 1, wherein the conductive polymer (A) is poly (alkylenedioxythiophene). 3. The semiconductive belt or roller according to claim 1, wherein the conductive polymer (A) is poly (3-alkylthiophene). 4. The heat-resistant resin (B) is at least one selected from the group consisting of a crystalline resin having a melting point of 150 ° C. or higher, an amorphous resin having a glass transition temperature of 150 ° C. or higher, and a condensed wholly aromatic polyimide. The semiconductive belt or roller according to claim 1, which is a heat resistant resin. 5. The semiconductive belt or roller according to claim 1, wherein the heat resistant resin (B) is a polyamideimide or a condensed wholly aromatic polyimide. 6. The volume resistivity of the semiconductive resin layer measured at a temperature of 20 ° C. and a voltage of 100 V is 1.0 × 10 ^{4 to} 1.0 ×.
2. The semiconductive belt or roller according to claim 1, wherein said belt or roller has a range of 10 ¹⁶ Ω · cm. 7. The surface resistivity of the outer surface of the semiconductive resin layer measured at a temperature of 20 ° C. and a voltage of 100 V is from 1.0 × 10 ⁵ to
2. The semiconductive belt or roller according to claim 1, wherein the range is 1.0 × 10 ¹⁶ Ω / □. 8. The ratio (ρs / ρ) of the volume resistivity (ρv; Ω · cm) to the surface resistivity (ρs; Ω / □) of the outer surface of the semiconductive resin layer measured at a temperature of 20 ° C. and a voltage of 100 V.
2. The semiconductive belt or roller according to claim 1, wherein v) is 10 or more. 9. It is formed of a semiconductive resin layer,
Alternatively, in a method for manufacturing a semiconductive belt or roller having a structure in which a semiconductive resin layer is formed on a base, (1)
Conductive polymer (A) and the heat-resistant resin (B) or a precursor thereof in the main chain having a thiophene ring (B ₁₎ and the weight ratio (A: B or _{A: B 1) 2: 98~45} : 55 And an organic solvent for a resin composition containing a fluorosurfactant (C) having a perfluoroalkyl group as a hydrophobic group in an amount of 0.01 to 5% by weight based on the total amount of the resin composition. A first step of preparing a solution, and (2) applying the organic solvent solution onto a support or a substrate, drying and, if necessary, heat-treating the conductive polymer (A) and the heat-resistant resin. (B) and the weight ratio (A: B) 2: 98-4.
5: A method for producing a semiconductive belt or roller including a second step of forming a semiconductive resin layer made of a resin composition contained in a range of 55. 10. The heat-resistant resin (B) in the first step
Or an organic solvent solution containing its precursor (B ₁ )
Adding a monomer capable of forming the conductive polymer (A), polymerizing the monomer in situ to synthesize the conductive polymer (A), and then adding a fluorine-based surfactant (C) The method according to claim 9, wherein a solution of the resin composition in an organic solvent is prepared.