JP2005179652A - Semi-electrically conductive seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low cost semi-electrically conductive seamless belt with excellent durability and giving an excellent image quality. <P>SOLUTION: This semi-electrically conductive seamless belt is provided with at least a base layer 1, and the base layer 1 is formed of an electrically conductive composition essentially having below mentioned components (A)-(D). (A) is a polyether sulfone resin, (B) is a polyamide-imide resin, (C) is an electrically conductive filler and (D) is a thermoplastic resin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semi-conductive seamless belt that is low in cost, excellent in durability, and capable of obtaining excellent image quality, and more specifically, electrophotography such as full-color LBP (laser beam printer) and full-color PPC (plain paper copier). The present invention relates to a semiconductive seamless belt used for an intermediate transfer belt, a paper transfer conveyance belt, and the like in an electrophotographic apparatus employing the technology.

  In general, seamless belts (endless belts) are frequently used in applications such as toner image transfer, paper transfer conveyance, and photoconductor substrate in electrophotographic equipment employing electrophotographic technology such as full color LBP and full color PPC. Yes. As such a seamless belt, for example, a conductive resin black blended with fluorine resin such as PVDF (polyvinylidene fluoride), polycarbonate resin, polyimide resin, etc., dipping method, extrusion molding method, centrifugal molding method What was formed in the cylindrical film by the shaping | molding methods etc. is used.

  However, although the fluororesin belt is excellent in electric characteristics, it has a drawback that the belt physical properties such as elastic modulus are low and the cost is high. Although the polycarbonate resin belt has an advantage of low cost, it is usually formed by extrusion molding. Therefore, there is a problem that electric resistance varies greatly and belt properties such as flexibility are inferior. In addition, although the polyimide resin belt has no particular problem with respect to belt properties, there are problems in that electrical characteristics vary greatly from lot to lot and cost is high. Such low belt properties and variations in electrical resistance cause a reduction in the image quality of the copied image.

In addition, as a charging member for a photosensitive drum, an aromatic polyether sulfone resin containing 5 to 30% by weight of a powdery conductive agent such as carbon black and 5 to 30% by weight of powdered glass as a main component is used as a film. A semiconductive aromatic polyethersulfone film formed into a thin film has been proposed (see Patent Document 1).
JP-A-9-237519

  In the above-mentioned Patent Document 1, there is a description that the semiconductive aromatic polyethersulfone film is used as a charging member for a photosensitive drum, but there is no description that it is used as a seamless belt such as an intermediate transfer belt. Even if the semiconductive aromatic polyethersulfone film described in Patent Document 1 is used as an intermediate transfer belt, the belt composed only of the semiconductive aromatic polyethersulfone film is mainly made of polyethersulfone. Since it is a component, it has a drawback that it is weak against tearing force due to high strength and inferior in durability.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a semiconductive seamless belt that is low in cost, excellent in durability, and capable of obtaining excellent image quality.

In order to achieve the above object, the semiconductive seamless belt of the present invention is a semiconductive seamless belt having at least a base layer, and the base layer includes the following (A) to (D) as essential components. It is configured to be formed using a conductive composition.
(A) Polyethersulfone resin.
(B) Polyamideimide resin.
(C) Conductive filler.
(D) Thermoplastic resin.

  As a result of intensive studies, the present inventors have determined that the base layer (base layer) is a polylayer semi-conductive seamless belt consisting of a single layer consisting of only the base layer or a multilayer including two or more layers including the base layer. When using ethersulfone resin and polyamide-imide resin in combination, and by adding a conductive filler to this, it has been found that a semi-conductive seamless belt with low cost, excellent durability and high image quality can be obtained, A patent application was filed for this semiconductive seamless belt (Japanese Patent Application No. 2003-82471). However, as a result of further research on the semiconductive seamless belt according to the above patent application, it has been found that there is room for improvement in terms of durability (bending resistance). As a result of continuous research, in the single layer consisting of only the base layer or the multi-layer semi-conductive seamless belt consisting of two or more layers including the base layer, the base layer (base layer) is made of polyethersulfone resin and polyamide. When used in combination with an imide resin, a conductive filler is added to the resin and a thermoplastic resin is added to the belt, flexibility can be imparted to the belt and durability (flex resistance) can be further improved. And the present invention has been reached.

  The semiconductive seamless belt of the present invention has a conductive property comprising a polyethersulfone resin (component A), a polyamideimide resin (component B), a conductive filler (component C) and a thermoplastic resin (component D) as essential components. A base layer is formed using the composition. The polyethersulfone resin (component A) is low in cost, has little elongation, has excellent curl habit characteristics (low curl wrinkles), and the polyamideimide resin (component B) has excellent durability. The semiconductive seamless belt of the invention is low in cost and excellent in durability due to the combined effect of the polyethersulfone resin (component A) and the polyamideimide resin (component B). Misaligned images can be prevented. Moreover, the semiconductive seamless belt of the present invention uses a thermoplastic resin (D component) together with the polyethersulfone resin (A component), the polyamideimide resin (B component), and the conductive filler (C component). Therefore, flexibility can be imparted to the belt, and more excellent durability (flexibility) can be obtained.

  Further, if a special surface layer is formed on the outer periphery of the base layer directly or via another layer, filming due to damage or cracking caused by toner can be prevented, and transfer efficiency can be improved.

  Further, when a thermoplastic resin layer or a surface layer is formed on the surface of the base layer directly or via another layer to form a multilayer structure, the base layer and the thermoplastic resin layer or the surface layer provide a surface resistance and a volume resistance. Can be controlled separately, and the electrical characteristics can be easily controlled, so that the transfer efficiency is improved.

  Further, when a rubber elastic layer is formed between the base layer and the surface layer, the flexibility is improved, and it becomes easier to follow the toner amount and the surface property of the paper, thereby further improving the toner transfer efficiency.

  Next, an embodiment of the present invention will be described.

  The semiconductive seamless belt of the present invention is configured, for example, by directly forming a surface layer 2 on the outer peripheral surface of a base layer 1 as shown in FIG. In the present invention, the base layer 1 has a conductive property comprising a polyethersulfone resin (component A), a polyamideimide resin (component B), a conductive filler (component C), and a thermoplastic resin (component D) as essential components. It is formed using a composition, and this is the greatest feature.

Here, the “semiconductive” in the semiconductive seamless belt of the present invention means that the volume resistivity of the base layer 1 is in the range of 10 ⁴ to 10 ¹⁶ Ω · cm, preferably 10 ⁵ to 10 ¹³ Ω · cm. It means being in the range of cm. In addition, the said volume electrical resistivity shows the value at the time of applying a voltage of 100V using Hiresta-UP MCP-HT450 (made by Mitsubishi Chemical Corporation) and HRS probe (made by Mitsubishi Chemical Corporation).

As the polyethersulfone (PES) resin (component A) that is an essential component of the conductive composition forming the base layer 1, the aromatic ring is a sulfonyl group (—SO ₂ —) or an ether group (—O—). There is no particular limitation as long as the structural unit bonded via a repeating unit is a repeating unit. The PES resin is a solid polymer obtained by polymerizing such a structural unit as a repeating unit, and is a high molecular weight material that can be plasticized by heat and formed into a film by extrusion or the like. The plasticizing temperature (softening temperature) by this heat is usually in the range of about 200 to 270 ° C., although there is a slight difference depending on the degree of polymerization (n).

  The structural unit is not particularly limited, but structural units represented by the following chemical formulas (1) to (3) are preferably used. The PES resin (component A) is not limited to a single repeating unit of the structural units represented by the chemical formulas (1) to (3), and the chemical formulas (1) to (3). There may be a case in which two or more structural units represented by the formula are used as repeating units.

  The PES resin (component A) having the structural unit represented by the chemical formula (1) as a repeating unit is, for example, an equimolar amount of 4,4′-dihydroxydiphenylsulfone and 4,4′-dichlorodiphenylsulfone, It can synthesize | combine by mixing in an organic polar solvent, and usually carrying out condensation polymerization under a 150-350 degreeC heating.

  In addition, the PES resin (component A) having the structural unit represented by the chemical formula (2) as a repeating unit is equivalent to an organic polar solvent of 4,4′-dichlorophenylsulfone and 1,4-dihydroxyphenyl. It can be synthesized by mixing in the mixture and condensation polymerization usually under heating at 150 to 350 ° C.

  Further, the PES resin (component A) having the structural unit represented by the chemical formula (3) as a repeating unit is an organic polar solvent containing an equimolar amount of 4,4′-dichlorophenylsulfone and 4,4-dihydroxydiphenyl. It can be synthesized by mixing in the mixture and condensation polymerization usually under heating at 150 to 350 ° C.

  The organic polar solvent is not particularly limited, but is preferably one that can dissolve both the starting material and the synthesized PES resin (component A). For example, N, N-dimethylformamide (DMF), N, N -Dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP) and the like.

  Note that the structural unit represented by the chemical formula (3) is not limited to one in which two phenyl groups are directly connected, and two phenyl groups may be bonded through an alkylene group or the like.

  The number average molecular weight (Mn) of the PES resin (component A) is preferably in the range of 10,000 to 500,000, particularly preferably in the range of 20,000 to 400,000.

  Next, the polyamide-imide (PAI) resin (component B) used together with the PES resin (component A) is not particularly limited as long as it has a molecular structure by a combination of a benzene ring, an imide group and an amide group. In addition, various reactive groups, functional groups, etc. may be modified in the molecular structure such as molecular ends.

  Examples of the PAI resin (component B) include those produced by a known method such as an acid chloride method or an isocyanate method.

  Examples of the acid component used for the production of the PAI resin (component B) include trimellitic acid and its anhydride or acid chloride, benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid), Tetracarboxylic acids such as biphenyltetracarboxylic acid, biphenylsulfonetetracarboxylic acid, benzophenonetetracarboxylic acid, biphenylethertetracarboxylic acid, ethylene glycol bistrimellitate, propylene glycol bistrimellitate and their anhydrides, oxalic acid, adipic acid, Aliphatic dicarboxylic acids such as malonic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dicarboxypolybutadiene, dicarboxypoly (acrylonitrile-butadiene), dicarboxypoly (styrene-butadiene), 1,4-cyclohexane Carboxylic acid, 1,3-cyclohexanedicarboxylic acid, 4,4'-dicyclohexylmethanedicarboxylic acid, alicyclic dicarboxylic acid such as dimer acid, terephthalic acid, isophthalic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, naphthalenedicarboxylic acid, etc. And aromatic dicarboxylic acids. These may be used alone or in combination of two or more. Among these, trimellitic anhydride is preferably used in terms of reactivity, heat resistance, solubility, and the like.

  Examples of the diamine or diisocyanate used in the production of the PAI resin (component B) include aliphatic diamines such as ethylenediamine, propylenediamine, and hexamethylenediamine, and diisocyanates thereof, 1,4-cyclohexanediamine, 1,3- Cycloaliphatic diamine, isophorone diamine, alicyclic diamine such as 4,4'-dicyclohexylmethane diamine, and diisocyanates thereof, m-phenylene diamine, p-phenylene diamine, 4,4'-diaminodiphenyl methane, 4,4-diaminodiphenyl ether, Aromatic diamines such as 4,4'-diaminodiphenylsulfone, benzidine, o-tolidine, 2,4-tolylenediamine, 2,6-tolylenediamine, xylylenediamine and the like Cyanate and the like. These may be used alone or in combination of two or more. Among these, 4,4'-diaminodiphenylmethane and its diisocyanate, 2,4-tolylenediamine and its diisocyanate, o-tolidine and its diisocyanate, isophoronediamine, from the viewpoints of heat resistance, mechanical properties, solubility, etc. And its diisocyanate are preferably used.

  The PAI resin (component B) can be easily produced by stirring in a polar solvent such as DMF, DMAC, NMP, and γ-butyrolactone while heating at 60 to 200 ° C.

  The mixing ratio of the PES resin (component A) to the PAI resin (component B) is preferably in the range of component A / component B = 99/1 to 1/99, particularly preferably component A / component. B component = within a range of 90/10 to 10/90. That is, the mixing ratio of the A component and the B component is set to an optimum ratio in accordance with the required characteristics within this range. For example, when a small-diameter roller is arranged or a belt unit having a large bending angle is used, the curl In order to improve the wrinkle characteristics, the ratio of the component A is set to be high. On the other hand, when durability is important, the component B is rich in toughness and high tearing force is obtained. The ratio is set so as to increase the ratio.

The conductive filler (C component) used together with the PES resin (component A) and the PAI resin (component B) is not particularly limited. For example, conductive powder such as carbon black and graphite, aluminum powder, stainless steel, and the like. Metal powder such as powder, conductive zinc oxide (c-ZnO), conductive titanium oxide (c-TiO ₂ ), conductive iron oxide (c-Fe ₃ O ₄ ), conductive tin oxide (c-SnO ₂ ) Examples thereof include ionic conductive agents such as conductive metal oxides such as quaternary ammonium salts, phosphate esters, sulfonates, aliphatic polyhydric alcohols, and aliphatic alcohol sulfate salts. These may be used alone or in combination of two or more.

  The blending ratio of the conductive filler (component C) is preferably in the range of 0.1 to 30 parts relative to 100 parts by weight (hereinafter abbreviated as “part”) of the total amount of component A and component B, Especially preferably, it exists in the range of 1-20 parts. That is, when the conductive filler (C component) is less than 0.1 part, the potential necessary for transfer is not expressed on the belt surface, and the transfer efficiency tends to deteriorate. Conversely, when it exceeds 30 parts, This is because the flexibility of the belt deteriorates and the mechanical durability tends to deteriorate.

  The thermoplastic resin (D component) used together with the A to C components is not particularly limited, but is excellent in compatibility with PES resin (A component) and PAI resin (B component), and is a semiconductive seamless belt. Those which can impart flexibility are preferred, for example, fluorine resins, epoxy resins, polyester resins, polyamide (PA) resins, acrylic resins such as polymethyl methacrylate (PMMA), polyacetal (POM), polybutylene terephthalate (PBT). Polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polycarbonate (PC), polyphenylene ether (PPE), polyarylate (PAR), polyether imide (PEI) and the like. These may be used alone or in combination of two or more. Among these, fluorine-based resins, epoxy resins, polyester resins, and polyamide (PA) resins are preferable, and they are particularly excellent in compatibility with PES resins (component A) and PAI resins (component B), and are flexible and have high tear strength. A fluorine-based resin and an epoxy resin are particularly preferable in that it is easy to ensure elongation physical properties while imparting.

  The fluororesin is not particularly limited as long as it has a fluoromonomer as a structural unit. For example, polyvinylidene fluoride (PVDF), vinylidene fluoride-tetrafluoroethylene copolymer [Poly (Vdf- TFE)], ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). These may be used alone or in combination of two or more. Among these, PVDF is preferably used in that it is soluble in a solvent and easily paints.

  The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule and can be produced by this ring-opening reaction, and is mainly produced by condensation of bisphenol A and epichlorohydrin. can do. Examples of the epoxy resin include bisphenol A-epichlorohydrin resin, epoxy novolac resin, alicyclic epoxy resin, aliphatic epoxy resin, heterocyclic epoxy resin, glycidyl ester epoxy resin, brominated epoxy resin, and the like. . These may be used alone or in combination of two or more. Among these, liquid aliphatic epoxy resins are preferably used from the viewpoints of flexibility and compatibility.

  Examples of the polyester resin include those obtained using an acid component and a polyhydric alcohol component. Examples of the acid component include maleic anhydride, phthalic acid, itaconic acid, phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, tetrahydrophthalic anhydride, alicyclic dibasic acid, fatty acid, phosphoric acid, trimellitic acid Citric acid and the like. These may be used alone or in combination of two or more. Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, trimethylolpropane monoallyl ether, and bisphenol A ethylene oxide addition. Or propylene oxide adduct, polybutadiene glycol, hydrogenated polybutadiene glycol, hydrogenated bisphenol A, and the like. These may be used alone or in combination of two or more.

  Examples of the polyamide (PA) resin include polyamide 6, polyamide 66, polyamide 610, polyamide 46, polyamide 12, reinforced polyamide incorporating an aromatic ring in the basic skeleton, and modified polyamide. These may be used alone or in combination of two or more.

  The blending ratio of these thermoplastic resins (component D) is preferably in the range of 0.1 to 50 parts, particularly preferably with respect to 100 parts in total of PES resin (component A) and PAI resin (component B). Within the range of 1-30 parts. That is, if the D component is less than 0.1 part, sufficient flexibility (toughness) cannot be obtained, and the effect of improving the durability is low. Conversely, if the D component exceeds 50 parts, the elastic modulus decreases. This is because the creep rate tends to deteriorate and the curl tendency tends to deteriorate.

  In addition, the conductive composition forming the base layer 1 can contain an organic solvent such as DMF, DMAC, toluene, acetone, NMP, and a filler as necessary, in addition to the above components.

  The conductive composition forming the base layer 1 includes, for example, a PES resin (component A), a PAI resin (component B), a conductive filler (component C), a thermoplastic resin (component D), and an organic material. A solvent and a filler as necessary can be appropriately blended, mixed with a stirring blade, and then dispersed by using a ring mill, a ball mill, a sand mill or the like.

  Next, the material for the surface layer 2 formed on the outer peripheral surface of the base layer 1 is not particularly limited, but the pencil hardness of the surface layer 2 is in the range of B to 5H, and the contact angle of pure water is 60 to 60. A material having a range of 120 ° is preferable, and a material having a pencil hardness of F to 2H and a contact angle of pure water of 80 to 120 ° is more preferable. That is, when the pencil hardness of the surface layer 2 is less than B, the toner damages the surface layer 2 and filming occurs. Conversely, when the pencil hardness exceeds 5H, the surface layer 2 is easily cracked, and filming starts from the cracked portion. This is because there is a risk of occurrence. In addition, if the contact angle of pure water is less than 60 °, cleaning failure after secondary transfer occurs. Conversely, if the contact angle exceeds 120 °, the transfer efficiency of primary transfer deteriorates. is there.

  The pencil hardness is a value measured according to the pencil scratch value of JIS K5600-5-4. The contact angle is a value measured according to JIS R3257.

  The thickness of the surface layer 2 is preferably in the range of 0.1 to 10 μm, particularly preferably in the range of 0.5 to 5 μm. That is, when the thickness of the surface layer 2 is less than 0.1 μm, the function of the surface layer 2 is not sufficiently exhibited, the base layer 1 is easily scratched, and conversely, when the thickness of the surface layer 2 exceeds 10 μm, deformation (roll This is because the surface layer 2 is liable to crack and filming may occur.

  Specific examples of the material for the surface layer 2 include silicone resins, fluorine resins, urethane resins, acrylic resins, polyamide resins, and the like. These may be used alone or in combination of two or more. Among these, liquid or solvent-soluble types are preferably used in consideration of normal workability. In addition, for the purpose of preventing dirt, improving the strength of the coating film, or improving the adhesion, a modified resin material may be used, for example, a modified acrylic resin. The modified acrylic resin is not particularly limited as long as it is based on the molecular structure of the acrylic resin and is modified with another resin or resin component, but a silicone-modified acrylic resin is preferably used.

  Examples of the silicone-modified acrylic resin include a silicone graft acrylic resin. The silicone graft acrylic resin is not particularly limited as long as the silicone resin is graft polymerized with the acrylic resin (main chain). Specific examples of this silicone graft acrylic resin include Saimak US-350 manufactured by Toagosei Co., Ltd.

  In addition, as the material for the surface layer 2, a material obtained by subjecting the resin material to resin crosslinking using a resin crosslinking agent such as isocyanate resin, amino resin, phenol resin, xylene resin, or the like, photosensitive monomer or polymer An ultraviolet curable material in which a photopolymerization initiator is mixed may be used.

  The material for the surface layer 2 can be prepared, for example, by appropriately blending a modified acrylic resin and an organic solvent such as DMF, toluene, and acetone and mixing them with a stirring blade. In order to form each layer with high accuracy, it is preferable to use different types of organic solvents as materials for forming adjacent layers. That is, it is preferable to use different types of organic solvents for the surface layer 2 material and for the organic solvent used for the base layer 1 material.

  The semiconductive seamless belt of the present invention shown in FIG. 1 can be produced, for example, as follows. That is, a base layer material is prepared in the same manner as described above, and this is spray-coated on the surface of a mold (cylindrical substrate). Next, this is dried at 150 to 300 ° C. for 3 to 6 hours to form the base layer 1 on the surface of the mold. Next, the surface layer 2 material prepared in the same manner as described above is coated on the surface of the base layer 1 by the dipping method and dried, and then air blown between the base layer 1 and the cylindrical substrate, A seamless base belt (see FIG. 1) having a two-layer structure in which the surface layer 2 is formed on the surface of the base layer 1 by extracting the cylindrical substrate can be produced. In addition, the formation method of the surface layer 2 is not limited to the said dipping method, You may form by spray coating similarly to the formation method of the base layer 1.

  Further, the base layer 1 of the semiconductive seamless belt of the present invention is produced by an extrusion molding method, an inflation method, a blow molding method, a dipping method, a nozzle coating method (Japanese Patent Application No. 2002-273691), etc. in addition to the above production method. It is also possible to do. Then, by omitting the formation of the surface layer 2, a seamless belt having a single layer structure consisting only of the base layer 1 can be produced.

  The thickness of each layer of the semiconductive seamless belt of the present invention is appropriately set according to the use of the belt, but the thickness of the base layer 1 is usually in the range of 30 to 300 μm, preferably 50 to 200 μm. Within range. Further, as described above, the thickness of the surface layer 2 is preferably in the range of 0.1 to 10 μm, particularly preferably in the range of 0.5 to 5 μm. The semiconductive seamless belt of the present invention preferably has an inner peripheral length of 90 to 1500 mm and a width of about 100 to 500 mm. That is, if the size is set within the above range, the size is appropriate for use in an electrophotographic copying machine.

  Note that the semiconductive seamless belt of the present invention only needs to have a structure including at least the base layer 1, and is limited to a two-layer structure in which the surface layer 2 is directly formed on the outer peripheral surface of the base layer 1 as shown in FIG. Is not to be done. The semiconductive seamless belt of the present invention has, for example, a single-layer structure composed of only the base layer 1, a three-layer structure in which a thermoplastic resin layer or a rubber elastic layer is interposed between the base layer 1 and the surface layer 2, the base layer 1 and A four-layer structure in which both a thermoplastic resin layer and a rubber elastic layer are interposed between the surface layer 2 and the like may be used. However, the base layer 1 is formed using a conductive composition containing PES resin (component A), PAI resin (component B), conductive filler (component C) and thermoplastic resin (component D) as essential components. Need to be.

  The material for the thermoplastic resin layer interposed between the base layer 1 and the surface layer 2 is not particularly limited, but a solvent such as methyl ethyl ketone (MEK) or toluene is used as necessary together with the thermoplastic resin. . In addition, the conductive filler (component C) as described above may be blended in this thermoplastic resin layer material.

  The thermoplastic resin is not particularly limited, but when the thermoplastic resin layer is directly formed on the outer periphery of the base layer 1, a thermoplastic resin other than the PES resin (component A) and the PAI resin (component B) is used. It is preferable. Examples of the thermoplastic resin other than the PES resin (component A) and the PAI resin (component B) include, for example, polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and ethylene-tetrafluoro. Fluorine resin such as ethylene copolymer (ETFE), polyethylene resin, polystyrene resin, acrylic resin, polycarbonate (PC) resin, polyamide resin, EVA (ethylene-vinyl acetate copolymer) resin, EEA (Ethylene-ethyl acrylate copolymer) -based resin and the like. These may be used alone or in combination of two or more. Among these, it is preferable to use a fluorine-based resin such as PVDF from the viewpoint of excellent flame retardancy. In addition, when forming a thermoplastic resin layer in the outer periphery of the base layer 1 through another layer, PES resin (A component) and PAI resin (B component) may be used as a thermoplastic resin.

  Thus, a three-layer semiconductive seamless belt having a thermoplastic resin layer interposed between the base layer 1 and the surface layer 2 can be produced, for example, as follows. That is, the base layer 1 is formed by the same spray coating as described above, and the thermoplastic resin layer material is coated on the surface of the base layer 1 by the same manufacturing method, dipping method, etc. Form a layer. And it can produce by forming the surface layer 2 as mentioned above on this. The thickness of this thermoplastic resin layer is usually in the range of 10 to 200 μm, preferably in the range of 10 to 100 μm.

  The rubber elastic layer material interposed between the base layer 1 and the surface layer 2 may be a vulcanization accelerator, a solvent, a processing aid, an anti-aging agent, etc. Is used. In this rubber elastic layer material, the conductive filler (component C) as described above may be blended.

  The rubber material is not particularly limited, and chlorinated polyethylene rubber (CPE), chloroprene rubber (CR) and the like are used from the viewpoint of flame retardancy. Among these, the optimum material is selected according to the electrical characteristics, elasticity, and durability required for each intermediate transfer belt.

  Thus, a semi-conductive seamless belt having a three-layer structure in which a rubber elastic layer is interposed between the base layer 1 and the surface layer 2 can be produced, for example, as follows. That is, the base layer 1 is formed by spray coating similar to that described above, and the surface of the base layer 1 is coated with the elastic elastic layer material by the same production method, dipping method, etc., and then heated and dried (vulcanized) to give the rubber. An elastic layer is formed. And it can produce by forming the surface layer 2 on this as described above. The thickness of this rubber elastic layer is usually in the range of 10 to 200 μm, preferably in the range of 10 to 100 μm.

  The semiconductive seamless belt of the present invention may have a four-layer structure in which both a thermoplastic resin layer and a rubber elastic layer are interposed between the base layer 1 and the surface layer 2. Such a semi-conductive seamless belt having a four-layer structure can be manufactured, for example, as follows. That is, the base layer 1 is formed by the same spray coating as described above, and the thermoplastic resin layer material is coated on the surface of the base layer 1 by the same manufacturing method, dipping method, etc. Form a layer. Next, the surface of the thermoplastic resin layer is coated with a material for a rubber elastic layer by the above-described manufacturing method, dipping method or the like, and then heated and dried (vulcanized) to form a rubber elastic layer. And it can produce by forming the surface layer 2 as mentioned above on this.

  The semiconductive seamless belt of the present invention is suitably used for applications such as toner image transfer, paper transfer conveyance, and photoreceptor substrate in electrophotographic equipment employing electrophotographic technology such as full color LBP and full color PPC. However, the present invention is not limited to this. For example, it can be used for a transfer belt of a monochrome electrophotographic copying machine which is not full color.

  Next, examples will be described together with comparative examples.

(Preparation of base layer material)
90 parts of PES resin (PES powder) having the structural unit represented by the chemical formula (1) as a repeating unit, 10 parts of PAI resin in solid content, and 5 parts of PVDF resin (Daikin Industries, Ltd., VT-100) 10 parts of carbon black (Showa Cabot, Show Black N220) and 600 parts of NMP solvent were mixed with a stirring blade and dispersed with a ball mill, then NMP solvent was added again, and the base layer for spraying The material was prepared.

(Preparation of surface material)
100 parts of a silicone graft acrylic resin (Saimak US-350, manufactured by Toagosei Co., Ltd.) and a toluene solvent were blended, and a surface layer material for dipping (DIP) was prepared while mixing with a stirring blade.

[Production of seamless belt]
A mold (cylindrical substrate) was prepared, and the base layer material was spray-coated on this surface to form a base layer on the surface of the mold. Next, after the surface layer material is coated on the surface of the base layer by dipping, the cylindrical base is removed by blowing air between the base layer and the cylindrical base, and the surface of the base layer (thickness: 80 μm) A seamless belt having a two-layer structure in which a surface layer (thickness: 1 μm) was formed was prepared.

  A base layer material was prepared in the same manner as in Example 1 except that 5 parts of a liquid aliphatic epoxy resin (Adeka Resin EP-4100, manufactured by Asahi Denka Kogyo Co., Ltd.) was used instead of 5 parts of the PVDF resin. And the seamless belt was produced like Example 1 except using this base layer material.

[Preparation of thermoplastic resin layer material]
100 parts of PVDF resin (Daikin Kogyo Co., Ltd., VT-100), 10 parts of carbon black (Showa Cabot Co., Show Black N220) and 500 parts of acetone solvent are mixed and mixed with a stirring blade, and a ball mill is used. Then, an acetone solvent was added again to prepare a thermoplastic resin layer material for spraying.

[Production of seamless belt]
After the base layer was formed in the same manner as in Example 2, the thermoplastic resin layer material was spray coated. Subsequently, this was heat-dried, the solvent was removed, and the thermoplastic resin layer was formed on the surface of the base layer. Next, a surface layer is formed on the surface of the thermoplastic resin layer in the same manner as in Example 1, and a thermoplastic resin layer (thickness: 20 μm) is formed on the surface of the base layer (thickness: 70 μm). A seamless belt having a three-layer structure in which a surface layer (thickness: 1 μm) was formed was prepared.

(Preparation of elastic layer material)
100 parts of chloroprene rubber (Denka Chloroprene A-30, manufactured by Denki Kagaku Kogyo Co., Ltd.), 1.5 parts of vulcanizing agent (manufactured by Sanshin Chemical Industry Co., Ltd., Sunseller 22C), carbon black (Ketjen Black International Co., Ltd., Ketjen) EC) 2 parts were kneaded and then dissolved in a MEK solvent to prepare an elastic layer material for spraying.

[Production of seamless belt]
After forming the base layer in the same manner as in Example 2, the elastic layer material was spray coated to form an elastic layer on the surface of the base layer. Next, a surface layer is formed on the surface of the elastic layer in the same manner as in Example 1, an elastic layer (thickness: 20 μm) is formed on the surface of the base layer (thickness: 70 μm), and a surface layer (thickness) is further formed on the surface. A seamless belt having a three-layer structure in which 1 μm) is formed was produced.

  A base layer material was prepared in the same manner as in Example 1 except that the blending ratio of the PVDF resin was changed to 0.1 part. And the seamless belt was produced like Example 1 except using this base layer material.

  A base layer material was prepared in the same manner as in Example 1 except that the blending ratio of the PVDF resin was changed to 50 parts. And the seamless belt was produced like Example 1 except using this base layer material.

  A base layer material was prepared in the same manner as in Example 1 except that the blending ratio of the PES resin (PES powder) was changed to 10 parts and the blending ratio of the PAI resin was changed to 90 parts in terms of solid content. And the seamless belt was produced like Example 1 except using this base layer material.

[Comparative Example 1]
(Preparation of base layer material)
100 parts of PES resin (PES powder) having the structural unit represented by the chemical formula (1) as a repeating unit, 10 parts of carbon black (Showa Cabot, Show Black N220), and 600 parts of NMP solvent are blended. After mixing with a stirring blade and dispersing in a ball mill, an NMP solvent was added again to prepare a base material for spraying.

[Production of seamless belt]
A seamless belt was produced in the same manner as in Example 1 except that the above base layer material was used.

[Comparative Example 2]
(Preparation of base layer material)
100 parts of PAI resin, 10 parts of carbon black (Showa Cabot, Show Black N220) and 600 parts of NMP solvent were blended and mixed with a stirring blade, dispersed in a ball mill, and again NMP solvent. Was added to prepare a base material for spraying.

[Production of seamless belt]
A seamless belt was produced in the same manner as in Example 1 except that the above base layer material was used.

[Comparative Example 3]
A base layer material was prepared in the same manner as in Example 1 except that no PVDF resin was blended. And the seamless belt was produced like Example 1 except using this base layer material.

[Comparative Example 4]
(Preparation of base layer material)
100 parts of PVDF resin (Daikin Kogyo Co., Ltd., VT-100), 10 parts of carbon black (Showa Cabot, Show Black N220) and 500 parts of acetone solvent are mixed and mixed with a stirring blade, and a ring mill is used. Then, an acetone solvent was added again to prepare a spray base material.

[Production of seamless belt]
A seamless belt was produced in the same manner as in Example 1 except that the above base layer material was used.

[Comparative Example 5]
(Preparation of base layer material)
100 parts of a polycarbonate resin (Sumitomo Dow, 301V-4) and 10 parts of carbon black (Showa Cabot, Show Black N220) were blended and kneaded using a roll to prepare a base layer material.

[Production of seamless belt]
The base layer material was extruded to form a cylindrical base layer having a thickness of 150 μm. Next, a surface layer was formed on the surface of the base layer in the same manner as in Example 1 to produce a seamless belt having a two-layer structure in which the surface layer was formed on the surface of the base layer.

  Using the seamless belts of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are shown together in Tables 1 and 2 below. In addition, according to the above-mentioned method, the pencil hardness of the surface layer and the contact angle of pure water were measured.

〔Growth rate〕
The seamless belt was cut into a size of 20 mm × 180 mm to produce a strip-shaped test piece. The test piece was hung on one end of the test piece under a load of 250 ± 5 g, and the elongation after standing for 24 hours in an environment of 50 ° C. × 95% was calculated.

[Opening angle]
As shown in FIG. 2, the seamless belt was cut into a size of 25 mm × 150 mm to produce a strip-shaped test piece 20. After the test piece 20 is wound around a metal pipe 21 having a diameter of 13 mm, the end portions of the test piece 20 are overlapped and suspended with a 0.3 kg weight (not shown). % Environment for 24 hours. Next, the weight is removed, and as shown in FIG. 3, both ends of the overlapped test piece 20 are opened, and the surfaces of the left and right test pieces 20 sandwiching the arc-shaped portion of the test piece 20 are directed upward. The angle θ created by the left and right virtual extensions 23 was measured as an opening angle θ. When the opening angle θ is close to 180 °, it indicates that there are few bends (curl wrinkles). If the opening angle θ is 90 ° or more, the image is not affected.

[Bench durability test]
Two metal rollers having a diameter of 13 mm were prepared, and one metal roller was fixed on the table in a state where a seamless belt (width 150 mm) was stretched between the two metal rollers. Next, the other metal roller not fixed to the table is placed at the end of the table, and 2 kg of weight is suspended from both ends of the metal roller (total load 4 kg), and the laboratory environment (25 ° C. × 40 %) And the seamless belt was rotated. Then, the cumulative number of revolutions until cracks could be confirmed in the seamless belt was measured.

[Uniformity of electrical resistance]
Volume electrical resistivity at eight locations on the inner circumference side of the seamless belt equally divided in the circumferential direction was measured according to JIS K6911, and the variation between the maximum value and the minimum value was displayed in digits. The applied voltage was 10V. In the evaluation, ◯ indicates that the variation is 0.5 digits or less, and △ indicates that the variation exceeds 0.5 digits and is 1 digit or less.

[Real machine image evaluation]
Each seamless belt was mounted on a full-color PPC, and 1,000 images were evaluated for evaluation, and the presence or absence of image defects such as a cleaning failure or transfer failure to the seamless belt was evaluated. In the evaluation, “◯” indicates that there is no image defect, and “X” indicates that there is an image defect.

  From the above results, all the products of the examples had a small elongation, a large opening angle, an excellent mechanical durability and electrical characteristics, and a good image evaluation. In addition, when a thermoplastic resin such as a polyester resin and a polyamide resin is used as the base layer material in place of the fluorine-based resin of Example 1 or the epoxy resin of Example 2, Example 1 and Example 2 It was confirmed by experiments that the same excellent effect was exhibited.

  On the other hand, the product of Comparative Example 1 was inferior in mechanical durability because no PAI resin was used as the base layer material. Since the comparative example 2 product did not use the PES resin as the base layer material, the elongation was large and the opening angle was small. The product of Comparative Example 3 uses a PES resin and a PAI resin in combination as the base layer material, so the elongation is small, the opening angle is large, the electrical characteristics are excellent, and the actual image evaluation is good, but the base layer material is a thermoplastic resin. Therefore, the mechanical durability was slightly inferior. The comparative example 4 product had a large elongation and a small opening angle. The product of Comparative Example 5 had a large elongation, a small opening angle, and inferior mechanical durability.

  The semiconductive seamless belt of the present invention is suitable for an intermediate transfer belt, a paper transfer conveyance belt, and the like in an electrophotographic apparatus employing an electrophotographic technology such as a full color LBP (laser beam printer) or a full color PPC (plain paper copier). Used.

It is a fragmentary sectional view showing an example of the semiconductive seamless belt of the present invention.

It is explanatory drawing which shows the measuring method of the opening angle of a semiconductive seamless belt.

It is explanatory drawing which shows the opening angle to measure.

Explanation of symbols

1 base layer 2 surface layer

Claims (4)

A semiconductive seamless belt having at least a base layer, wherein the base layer is formed using a conductive composition having the following (A) to (D) as essential components: Sex seamless belt.
(A) Polyethersulfone resin.
(B) Polyamideimide resin.
(C) Conductive filler.
(D) Thermoplastic resin.   A surface layer is formed on the outer periphery of the base layer directly or via another layer. The surface layer has a pencil hardness of B to 5H and a pure water contact angle of 60 to 120 °. The semiconductive seamless belt according to claim 1, which is set within a range.   The semiconductive seamless belt according to claim 2, wherein a thermoplastic resin layer is formed between the base layer and the surface layer.   The semiconductive seamless belt according to claim 2 or 3, wherein a rubber elastic layer is formed between the base layer and the surface layer.

Images