JP2005099182A - Semiconductive belt and electrophotographic image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductive belt which has satisfactory toner transferability even to paper of large ruggedness, such as recycled paper whose printing with high image quality is heretofore regarded to be difficult, which is excellent in formation of a nip shape in a transfer section, and in which hollow characters in the line image of transfer image quality is reduced, and which is less changed in electric resistance with time. <P>SOLUTION: The semiconductive belt 1 is used for an electrophotographic image forming apparatus and is constituted to include an outer layer 2 and an inner layer 3 disposed on the inner peripheral surface side of the outer layer 2, wherein the outer lasyr 2 is constituted by including a conductive resin composition consisting of (a) an epoxidation diene-based block copolymer and (b) a thermoplastic elastomer other than the epoxidation diene-based block copolymer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductive belt used for an intermediate transfer member or a paper transport belt provided in an electrophotographic image forming apparatus such as a copying machine or a printer, and electrophotographic image formation using the semiconductive belt Relates to the device.

  In an image forming apparatus using an electrophotographic system, first, a uniform charge is formed on the surface of an image carrier made of a photoconductive photoreceptor made of an inorganic or organic material, and the image signal is modulated with laser light or the like. After the electric image is formed, the electrostatic image is developed with a charged toner, and a visualized toner image is formed. The toner image is electrostatically transferred to a transfer material such as a recording sheet via an intermediate transfer member or directly, and fixed on the recording material to obtain a required reproduced image.

  In particular, there is known an image forming apparatus that employs a system in which a toner image formed on the image carrier is primarily transferred to an intermediate transfer member, and a toner image on the intermediate transfer member is secondarily transferred to a recording sheet (for example, , See Patent Document 1).

  In the image forming apparatus employing the intermediate transfer body method, the materials used for the intermediate transfer body are polycarbonate resin, PVDF (polyvinylidene fluoride), polyalkylene phthalate, PC (polycarbonate) / PAT (polyalkylene terephthalate) blend. Proposals have been made to use conductive endless belts of thermoplastic resins such as materials, ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, and PC / PAT blend materials (for example, Patent Documents 2 to 7). reference.).

Further, as a semiconductive belt that can be used for an intermediate transfer belt, a transfer conveyance belt, and the like, an intermediate transfer belt in which a conductive filler is dispersed in a polyimide resin excellent in mechanical properties and heat resistance has been proposed (for example, (See Patent Documents 8 and 9.)

However, since the above has a high belt surface hardness, the bias roller at the primary transfer portion that electrostatically transfers the toner image by pressing the recording paper against the recording medium using a bias roller and applying an electric field. Since there is little deformation due to the pressing force due to, the pressing force by the bias roller concentrates. For this reason, the toner aggregates and the charge density increases, so that discharge occurs inside the toner layer, causing image quality defects such as line image loss (holocharacter) due to causes such as changing the toner polarity. Sometimes caused problems. In recent years, special paper with irregularities on the surface such as colored paper and embossing has also been used, and the belt surface hardness is high, so the followability to such paper is poor, so toner transferability is poor. However, there is a drawback that it is extremely inferior.

  As a rubber belt material used in an image forming apparatus employing an intermediate transfer body method, an elastic belt with a reinforcing material formed by laminating a woven fabric such as polyester and an elastic member has been proposed. However, the elastic belt with a reinforcing material may cause a problem of color misregistration due to creep deformation of the belt material over time (see, for example, Patent Documents 10 and 11).

  As a belt material having a multilayer structure, for example, a multilayered endless belt made of plastic or a belt in which a polyolefin urethane layer is applied to the surface of a rubber belt has been proposed (see, for example, Patent Documents 12 and 13). .

  However, endless belts with a multilayer structure made of plastics have poor toner transferability due to the high hardness described above, and in recent years, special papers with irregularities on the surface such as colored paper and embossing have also been used. Therefore, since the following ability to paper is particularly bad, there is a problem that the transferability of toner is remarkably inferior. In addition, since the stress is large, the toner is easily destroyed, toner filming on the belt occurs, and the durability is inferior.

In addition, the belt having a polyolefin urethane layer coated on the rubber belt surface is sprayed with polyolefin urethane on the rubber belt, resulting in variations in coating thickness in the surface direction and poor dimensional accuracy. There are difficulties.
In addition, polyolefin-based urethane has a large amount of sag (deformation with time), and has a disadvantage that it adversely affects a copied image.
JP-A-62-206567 JP-A-6-095521 Japanese Patent Laid-Open No. 5-200904 JP-A-6-228335 Japanese Patent Laid-Open No. 6-149081 Japanese Patent Laid-Open No. 6-149083 Japanese Patent Laid-Open No. 6-149079 JP-A-5-77252 Japanese Patent Laid-Open No. 10-63115 Japanese Patent Laid-Open No. 9-305038 Japanese Patent Laid-Open No. 10-240020 Japanese Patent Laid-Open No. 11-24428 Japanese Patent Laid-Open No. 11-45015

An object of the present invention is to solve the conventional problems and achieve the following objects. In other words, the present invention has good toner transfer performance even on paper with large irregularities such as recycled paper, which has been conventionally difficult to print with high image quality, and can form a nip shape at the transfer portion. An object of the present invention is to provide a semiconductive belt which is excellent, has a line image with a transfer image quality being hollow (holocharacter), and has little change in electric resistance with time.
It is another object of the present invention to provide an electrophotographic image forming apparatus that includes the semiconductive belt and can stably obtain a high-quality transfer image quality.

Means for solving the above-described problems can be achieved by the present invention described below.
(1) A semiconductive belt used in an electrophotographic image forming apparatus,
At least an outer layer and an inner layer provided on the inner peripheral surface side of the outer layer are configured,
The outer layer includes a conductive resin composition comprising (a) an epoxidized diene block copolymer and (b) a thermoplastic elastomer other than the epoxidized diene block copolymer. Characteristic semi-conductive belt.

  (2) The semiconductive belt according to (1), wherein the thermoplastic elastomer is selected from a polyamide-based thermoplastic elastomer and a polyester-based thermoplastic elastomer.

  (3) The semiconductive belt according to (1) or (2), wherein the inner layer is formed of a thermoplastic resin composition having a Young's modulus of 1000 MPa or more.

  (4) The semiconductive belt according to any one of (1) to (3), wherein the inner layer is formed of a thermoplastic resin composition to which a conductive agent is added.

  (5) The semiconductive belt according to any one of (1) to (4), wherein the inner layer includes a fluorine-based resin.

(6) The inner layer is made of a thermoplastic resin composition having a volume resistivity of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, according to any one of (1) to (5), The semiconductive belt as described.

(7) The half according to any one of (1) to (6), wherein the outer layer and the inner layer each have a volume resistivity of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm. Conductive belt.

(8) The outer layer has a volume resistivity of 1 × 10 ¹³ Ωcm or more, and the inner layer has a volume resistivity of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm. The semiconductive belt according to any one of the above.

  (9) An electrophotographic image forming apparatus comprising the semiconductive belt according to any one of (1) to (8).

  (10) The electrophotographic image forming apparatus according to (9), wherein the electrophotographic image forming apparatus includes an intermediate transfer member, and the semiconductive belt is provided as the intermediate transfer member.

  (11) The electrophotographic image forming apparatus according to (9), wherein the electrophotographic image forming apparatus includes a paper transport belt, and the semiconductive belt is provided as the paper transport belt.

(12) The electrophotographic image according to any one of (9) to (11), wherein a spherical toner having a shape factor (ML ² / A) represented by the following formula of 140 to 100 is used. Forming equipment.
Formula: (ML ² / A) = [(absolute maximum length of toner particles) ² ] / [(projection area of toner particles) × π × 1 × 4 × 100]

  (13) The electrophotographic image forming apparatus according to any one of (9) to (12), wherein a neutralizing unit for neutralizing the semiconductive belt is provided.

According to the semiconductive belt of the present invention, toner transferability is good even for paper with large irregularities such as recycled paper, which has been conventionally difficult to print with high image quality, and at the transfer portion. It is excellent in forming a nip shape, and produces an effect that a line image of a transfer image quality is hollow (holo character), and further a change in electric resistance with time is small.
Further, according to the electrophotographic image forming apparatus of the present invention, there is an effect that a high quality transfer image quality can be obtained stably.

Hereinafter, the present invention will be described in detail.
[Semiconductive belt]
The semiconductive belt of the present invention will be described with reference to FIG. The semiconductive belt 1 of the present invention is an endless belt comprising, for example, an outer layer 2 as a surface layer and an inner layer 3 as a base material provided on the inner peripheral surface side thereof. The outer layer 2 includes a conductive resin composition comprising (a) an epoxidized diene block copolymer and (b) a thermoplastic elastomer other than the epoxidized diene block copolymer. . FIG. 1 is a cross-sectional view showing an example of the semiconductive belt of the present invention.

  As described above, the semiconductive belt of the present invention has at least a two-layer structure composed of the outer layer 2 and the inner layer 3 to satisfy the balance between flexibility and rigidity that cannot be obtained with a single material structure. be able to. Since the outer layer is composed of the specific conductive resin composition, the toner transferability is good even for paper with large irregularities such as recycled paper, which has been conventionally difficult to print with high image quality. In addition, it is possible to obtain a semiconductive belt that is excellent in forming a nip shape at the transfer portion, has a line image with a transfer image quality that is hollow (holocharacter), and has little change in electrical resistance over time.

<Outer layer>
As the material for the belt outer layer, a conductive resin composition comprising (a) an epoxidized diene block copolymer and (b) a thermoplastic elastomer other than the epoxidized diene block copolymer is used. The reason will be described below.

  First, since thermoplastic elastomer has elasticity, it can be used as an elastic material that can follow special paper with uneven surfaces such as colored paper and embossing, and thermoplastic elastomer is thermoplastic. Since it can be molded in the same way as resin, there are advantages in terms of environmental protection such as omission of the vulcanization process and recycling. Thermoplastic elastomers can be processed quickly with a molding machine for thermoplastic resins, compared to cross-linked elastomers, and the molding cycle is short and no vulcanization step is required. In other words, the manufacturing process is simple, and the material is energy-saving, labor-saving, and time-saving. Further, since the product is not cross-linked, there are effects such as easy recycling of scrap.

Examples of the elastic material include a vulcanized rubber material. Vulcanized rubber materials are very disadvantageous from the viewpoint of environmental protection because they consume energy in the vulcanization process at the time of manufacture and cannot be recycled by re-molding once vulcanized. I cannot deny that. Further, when an elastic body such as chloropyrene rubber in which carbon black or the like is dispersed is used as the transfer / conveying belt, the 10 ⁹ Ωcm level semiconductive resistance region is usually a region where resistance control is difficult. It is almost impossible to stably obtain a desired resistance value by adding ordinary conductive carbon black to the rubber material. It is difficult to stably produce variations in the resistance of elastic belts within one digit (log Ωcm value), and when the in-plane variation in resistance is more than one digit, transfer voltage cannot be applied uniformly, so transfer image quality is low. There is an unstable problem.

  Further, the belt holds the transfer material, and a transfer voltage of 1 kV to 5 KV is applied to transfer the toner image to the transfer material. This applied voltage changes the resistance value of the belt material, and the transfer material There arises a problem that the resistance value varies between a certain portion and a portion where there is no transfer material.

However, when this thermoplastic elastomer is applied to the surface layer of the semiconductive belt, deformation is likely to occur due to stress strain inherent in the material. Especially when the belt is stopped for a long time, it tends to be deformed according to the curvature of the support roll that stretches the belt, the transfer surface is not stable, and the transfer material cannot be stably conveyed by electrostatically attracting it. Problems may occur. Further, when an electron conductive conductive agent such as carbon black is used, if it is attempted to set it in a semiconductive region (about 10 ⁶ to 10 ¹² Ωcm), the resistance value varies greatly, and partial transfer failure, etc. Image defects will occur. The occurrence of this image defect may be caused by the difficulty in uniformly dispersing the electron conductive conductive agent in the thermoplastic elastomer, resulting in poor dispersion.

  Therefore, in the present invention, in order to prevent deformation due to stress strain inherent in the material, thermoplasticity other than (a) an epoxidized diene block copolymer and (b) an epoxidized diene block copolymer. A conductive resin composition comprising an elastomer is used.

  Hereinafter, (a) an epoxidized diene block copolymer and (b) a thermoplastic elastomer other than the epoxidized diene block copolymer will be described in detail.

(Epoxidized diene block copolymer)
(A) The epoxidized diene block copolymer uses a diene block copolymer as a raw material. The diene block copolymer is a polymer block mainly composed of a vinyl aromatic compound and a conjugated diene compound. The mass ratio of vinyl aromatic compound to conjugated diene compound (mass ratio of block copolymer) is preferably 5/95 to 90/10, 10/90 to 80/20 are preferred.

  The number average molecular weight of the diene block copolymer is preferably in the range of 5,000 to 1,500,000, more preferably in the range of 10,000 to 800,000. Moreover, it is preferable that molecular weight distribution [ratio (Mw / Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn)] is 10 or less. The molecular structure of the diene block copolymer may be linear, branched, radial, or any combination thereof. Specifically, for example, a vinyl aromatic compound (X) block having a structure such as X—Y—X, Y—X—Y—X, (X—Y) 4 Si, or XY—X—Y—X. -Conjugated diene compound (Y) block copolymer. Further, the unsaturated bond of the conjugated diene compound of the diene block copolymer may be partially hydrogenated.

  Examples of the vinyl aromatic compound constituting the diene block copolymer include styrene, α-methylstyrene, vinyltoluene, p-tertiary butylstyrene, divinylbenzene, p-methylstyrene, 1,1-diphenylstyrene, and the like. One or more types can be selected from among them, and styrene is preferable among them.

  Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, phenyl-1,3- One or two or more types are selected from butadiene and the like, and among them, butadiene, isoprene and combinations thereof are preferable.

  As a manufacturing method of the diene block copolymer, any manufacturing method can be used as long as it has the above-described structure. For example, a vinyl aromatic compound-conjugated diene compound block copolymer can be synthesized in an inert solvent using a lithium catalyst or the like.

  Furthermore, a partially hydrogenated block copolymer can be synthesized by hydrogenation in the presence of a hydrogenation catalyst in an inert solvent.

  And an epoxidized diene type block copolymer is obtained by epoxidizing the above-mentioned diene type block copolymer.

  The epoxidized diene block copolymer can be obtained by reacting the above block copolymer with an epoxidizing agent such as hydroperoxides and peracids in an inert solvent. Examples of peracids include performic acid, peracetic acid, and perbenzoic acid. In the case of hydroperoxides, a catalytic effect can be obtained by using a mixture of tungstic acid and caustic soda with hydrogen peroxide, organic acid with hydrogen peroxide, or molybdenum hexacarbonyl with tertiary butyl hydroperoxide. . There is no strict limitation on the amount of epoxidizing agent, and the optimum amount in each case depends on variable factors such as the particular epoxidizing agent used, the desired degree of epoxidation, the particular block copolymer used. .

  Isolation of the resulting epoxidized diene block copolymer is an appropriate method, for example, precipitation with a poor solvent, a method in which the polymer is poured into hot water with stirring, and the solvent is distilled off. It can be done by law.

  The epoxy equivalent of the obtained epoxidized diene block copolymer is preferably in the range of 200 to 10,000.

  Specific examples of the epoxidized diene block copolymer include Epofriend A1020 and Epofriend A1010 manufactured by Daicel Chemical Industries, Ltd., which have an epoxy group in a part of the diene molecule of butadiene in the styrene-butadiene block copolymer. Epofriend A1005 is mentioned.

The blending ratio of the epoxidized diene block copolymer is 1 to 30 parts by weight, preferably 3 to 25 parts by weight, and more preferably 5 to 20 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer (b). is there.
When the blending amount of the epoxidized diene block copolymer is less than 1 part by mass, the effect of improving the amount of compressive strain of the elastic body due to the addition of the epoxidized diene block copolymer may be small. When the amount exceeds the range, the softness of the elastic body may not be obtained.

(Thermoplastic elastomers other than epoxidized diene block copolymers)
Examples of the thermoplastic elastomer include a styrene thermoplastic elastomer, a polyolefin thermoplastic elastomer, a polyester thermoplastic elastomer, and a polyamide thermoplastic elastomer. Among these, from the viewpoint of hardness, it is preferable to select from a polyamide-based thermoplastic elastomer and a polyester-based thermoplastic elastomer.

  The polyamide-based thermoplastic elastomer is a thermoplastic elastomer composed of a polyamide segment and a polyether segment. Examples of suitable materials for use in the present invention include Ube Industries "UBE-PAE", Daicel Hiurus "Daiamide-PAE", ATochem "Pebax", EMS (Ems Japan) “Grillon” “Grillamide”, EMS (Dainippon Ink Chemical) “Glais A”, EMS (Mitsubishi Chemical) “Novamid EL” DOW Chemical “Estomid”

  As suitable polyester-based thermoplastic elastomers, Mitsubishi Rayon “Dia Alloy R”, Toyobo “Perprene”, DuPont “Hytrl”, AKZO “Glois”, GE “Lomod”, Eastman “ “Ecdel”, Hoechst-Celanese “Ritrflex”, and “Enimont“ Piflex ”.

<Inner layer>
As the material for the belt inner layer, it is preferable to use a resin composition having a Young's modulus of 1000 MPa or more (preferably 2000 MPa) or more and satisfy the mechanical properties. With this configuration, the belt can satisfy the balance between flexibility and rigidity, which cannot be obtained more effectively with a single material configuration. For example, it is also suitable to use the resin composition which mixed the electrically conductive agent and adjusted the volume resistivity in the range of 1 * 10 < ⁸ > -1 * 10 < ¹³ > (omega | ohm) cm.

  Examples of the resin constituting the resin composition include polyimide resin, polyamideimide resin, fluorine resin, vinyl chloride vinyl acetate copolymer, polycarbonate resin, polyethylene terephthalate resin, vinyl chloride resin, ABS resin, and polymethyl. Examples thereof include a methacrylate resin and a polybutylene terephthalate resin. These may be used alone or in combination of two or more. Among these constituent resins, it is preferable to use a thermoplastic resin. In particular, polyimide resins and fluororesins are preferably used because they are excellent in both strength and bending fatigue properties. However, fluororesins are superior in thermoplasticity, so that they are different from thermoplastic elastomers compared to polyimide resins. This is advantageous in that integral molding is possible.

  As a polyimide resin, for example, an aromatic tetracarboxylic acid component and an aromatic diamine component are obtained by reacting in an organic polar solvent.

As aromatic tetracarboxylic acid components, pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5,6-biphenyl Tetracarboxylic acid, 2,2 ′, 3,3′-biphenyltetracarboxylic acid, 3
, 3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenyl ether
Tertetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-azobenzenetetracarboxylic acid Bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3,4 Dicarboxylphenyl) hexafluoropropane and the like, and a mixture of these tetracarboxylic acids may be used.

  The aromatic diamine component is not particularly limited, and m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine , P-xylylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4′-diaminonaphthalenediphenyl, benzidine, 3,3-dimethylbenzidine, 3,3 '-Dimethoxybenzidine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (oxy-p, p'-dianiline; ODA), 4,4'-diaminodiphenyl sulfide, 3, 3'-diaminobenzophenone, 4,4'-diaminophenyl sulfone, 4,4'-diaminoa Benzene, 4,4'-diaminodiphenylmethane, beta, beta-bis (4-amine phenyl) propane.

  Examples of the organic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide and the like. These organic polar solvents can be mixed with phenols such as cresol, phenol and xylenol, and hydrocarbons such as hexane, benzene and toluene, if necessary. Solvents are also used alone or as a mixture of two or more.

  On the other hand, examples of the fluorine-based resin include vinylidene fluoride-tetrafluoroethylene copolymer [Poly (VdF-TFE)], ethylene-tetrafluoroethylene copolymer (ETFE), and polychlorotrifluoroethylene (PCTFE). ), Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and the like. Among these, Poly (VdF-TFE) is preferably used.

(Conductive agent)
It is preferable to add a conductive agent imparting electronic conductivity or a conductive agent imparting ionic conductivity to the resin composition used for these outer layer and inner layer, if necessary, in combination of one kind or two or more kinds. It is.

  As an electron conductive conductive agent, metal or alloy such as carbon black, graphite, aluminum, nickel, copper alloy, tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide or tin oxide-antimony oxide composite oxide, etc. Examples of the metal oxide can be given.

  Examples of the ion conductive conductive agent include sulfonates and ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants. Furthermore, there is a method of blending conductive polymers. Examples of the conductive polymer include various (for example, styrene) copolymers with (meth) acrylates that bind a quaternary ammonium base to a carboxyl group, and a quaternary ammonium base. Polymers that bind quaternary ammonium bases, such as a copolymer of maleimide and methacrylate, which binds to styrene, polymers that bind alkali metal salts of sulfonic acids such as sodium polysulfonate, hydrophilic units of at least alkyl oxide in the molecular chain For example, polyethylene oxide, polyethylene glycol-based polyamide copolymer, polyethylene oxy-epichlorohydrin copolymer polyether amide imide, block type polymer having polyether as a main segment, and polyaniline , Polythiophene, polyacetylene, can be mentioned polypyrrole, polyphenylene vinylene and the like, can be used These conductive Porima undoped state, or in a doped state. The above-described electrical resistance can be stably obtained by using one or two or more of the above-mentioned conductive agent, conductive polymer, or surfactant.

  As the conductive agent, good dispersion stability is obtained because of its good dispersibility in the resin composition, resistance variation of the semiconductive belt can be reduced, electric field dependency is also reduced, and transfer is further improved. Acidic carbon black having a pH of 5 or less is preferred because electric field concentration due to voltage becomes less likely to improve the stability of electrical resistance over time.

(Acid carbon black of pH 5 or less)
Acidic carbon black having a pH of 5 or less can be produced by oxidizing carbon black to give a carboxyl group, a quinone group, a lactone group, a hydroxyl group, and the like. In this oxidation treatment, an air oxidation method in which contact is made with air in a high temperature atmosphere to react, a method of reacting with nitrogen oxides or ozone at room temperature, and an air oxidation at high temperature, followed by ozone oxidation at a low temperature. It can be performed by a method or the like. Specifically, acidic carbon black having a pH of 5 or less can be produced by a contact method. Examples of the contact method include a channel method and a gas black method. Moreover, acidic carbon black can also be manufactured by the furnace black method which uses gas or oil as a raw material. Further, if necessary, after performing these treatments, a liquid phase oxidation treatment with nitric acid or the like may be performed. Acidic carbon black can be produced by a contact method, but is usually produced by a closed furnace method. In the furnace method, only carbon black having a high pH and a low volatile content is usually produced, but the pH can be adjusted by subjecting it to the above-mentioned liquid phase acid treatment. For this reason, in the present invention, carbon black obtained by the Nes method production and adjusted to have a pH of 5 or less by post-treatment is also considered to be included in the acidic carbon black having a pH of 5 or less.

  The acidic carbon black has a pH value of preferably 5.0 or less, more preferably 4.5 or less, and even more preferably 4.0 or less. Oxidized carbon having a pH of 5.0 or less has an oxygen-containing functional group such as a carboxyl group, a hydroxyl group, a quinone group, and a lactone group on the outside, so that it has good dispersibility in the resin, so that good dispersion stability is obtained. In addition, the resistance variation of the semiconductive belt can be reduced and the electric field dependency is also reduced, and the electric field concentration due to the transfer voltage is less likely to occur.

  The pH of acidic carbon black is determined by adjusting an aqueous suspension and measuring with a glass electrode. Further, the pH of the carbon black can be adjusted by conditions such as the treatment temperature and treatment time in the oxidation treatment step.

  The acidic carbon black preferably has a volatile component content of 1 to 25% by mass, more preferably 3 to 20%, and even more preferably 3.5 to 15% by mass. When the content of the volatile component is less than 1% by mass, the effect of the oxygen-containing functional group adhering to the outside is lost, and the dispersibility in the binder resin may be reduced. On the other hand, if the content of the volatile component is higher than 25%, it may be decomposed when dispersed in the resin composition, or the amount of water adsorbed on the outer oxygen-containing functional group is increased. The appearance of the outer layer or inner layer may deteriorate.

  On the other hand, the dispersion | distribution in the said resin composition can be made more favorable because content of a volatile component shall be 1-25 mass%. The content of the volatile component can be determined from the ratio of organic volatile components (carboxyl group, hydroxyl group, quinone group, lactone group, etc.) that come out when carbon black is heated at 950 ° C. for 7 minutes.

  Here, two or more types of carbon black as the conductive agent may be contained. At that time, these carbon blacks are preferably substantially different in conductivity from each other, for example, those having different physical properties such as degree of oxidation treatment, DBP oil absorption, specific surface area by BET method utilizing nitrogen adsorption, etc. Use. When two or more types of carbon blacks having different conductivity are added in this way, for example, carbon black that expresses high conductivity is preferentially added, and then carbon black with low conductivity is added to adjust the surface resistivity. It is possible to do. Thus, even when two or more types of carbon black are contained, at least one of them can be mixed and dispersed by using acidic carbon black having a pH of 5.0 or less for at least one of them.

  Specific examples of acidic carbon black include “Printex 150T” (pH 4.5, volatile content 10.0% by mass) and “Special Black 350” (pH 3.5, volatile content 2.2%) manufactured by Degussa. %), “Special Black 100” (pH 3.3, volatile matter 2.2 mass%), “Special Black 250” (pH 3.1, volatile matter 2.0 mass%), “Special Black 5” ( pH 3.0, volatile content 15.0% by mass), “Special Black 4” (pH 3.0, volatile content 14.0% by mass), “Special Black 4A” (pH 3.0, volatile content 14.0% by mass) %), “Special Black 550” (pH 2.8, volatile content 2.5% by mass), “Special Black 6” (pH 2.5, volatile content 18.0% by mass), “Color Black FW200”. (PH 2.5, volatile content 20.0% by mass), “Color Black FW2” (pH 2.5, volatile content 16.5% by mass), “Color Black FW2V” (pH 2.5, volatile content 16.5) Mass%), “MONARCH1000” (pH 2.5, volatile content 9.5 mass%) manufactured by Cabot Corporation, “MONARCH 1300” (pH 2.5, 9.5 mass% volatile content) manufactured by Cabot Corporation, “MONARCH 1400” manufactured by Cabot Corporation (PH 2.5, volatile matter 9.0% by mass), “MOGUL-L” (pH 2.5, volatile matter 5.0% by mass), “REGAL400R” (pH 4.0, volatile matter 3.5% by mass) ) And the like.

  Acidic carbon black has better dispersibility in the resin composition due to the effect of the oxygen-containing functional groups present on the surface as described above compared to general carbon black. Higher is preferred. Thereby, since the amount of carbon black in the semiconductive belt increases, the effect of using acidic carbon black that can suppress the in-plane variation of the electric resistance value can be maximized.

  A content of acidic carbon black of 10 to 30% by mass is preferable because the effect of acidic carbon black can be exhibited, such as suppressing in-plane variation of the surface resistivity of the semiconductive belt. If the acidic carbon black is less than 10% by mass, the uniformity of the electrical resistance is lowered, and the in-plane unevenness of the surface resistivity and the electric field dependency may increase. On the other hand, if the content of acidic carbon black exceeds 30% by mass, it may be difficult to obtain a desired resistance value. Furthermore, it is more preferable to contain 18 to 30% by mass of acidic carbon black. By containing 18 to 30% by mass of acidic carbon black, the effect can be maximized, and in-plane unevenness of the surface resistivity can be achieved. And the electric field dependency can be remarkably improved.

(Volume resistivity)
The volume resistivity of the outer layer and the inner layer in the semiconductive belt of the present invention is applied to an electronic image forming apparatus provided with a neutralizing means for the semiconductive belt by applying an AC voltage after the secondary transfer, and this neutralizing means. The preferred volume resistivity region differs depending on the case where it is applied to an electrophotographic image forming apparatus that is not provided.

First, when applied to an electrophotographic image forming apparatus provided with static elimination means, the volume resistivity of the outer layer is 1 × 10 ¹³ Ωcm or more (preferably 2 × 10 ¹³ Ωcm or more), and the volume resistivity of the inner layer is 1 ×. It is preferably 10 ⁸ to 1 × 10 ¹³ Ωcm. When the volume resistivity of the outer layer is higher than 1 × 10 ¹³ Ωcm, the surface of the semiconductive belt is charged in the transfer electric field in the primary transfer when applied to an electrophotographic image forming apparatus provided with a charge eliminating means. In addition, since the charge holding force is increased, the problem that the toner is scattered around the image (blurring) due to the electrostatic repulsive force between the toners or the fringe electric field near the image edge is less likely to occur. .

On the other hand, when applied to an electrophotographic image forming apparatus not provided with a static elimination means, the outer layer and the inner layer both preferably have a volume resistivity of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, more preferably 1 ×. 10 ⁹ to 1 × 10 ¹² Ωcm. If the volume resistivity of the outer layer and the inner layer is 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, the toner scatters around the image due to electrostatic repulsion between the toners and the force of the fringe electric field near the image edge. (Blurring) problems are less likely to occur. In addition, within the above range, the volume resistivity of the semiconductive belt (especially when applied to an intermediate transfer member) is in a range where the charged charge is appropriately attenuated. Image formation can be performed continuously.

In addition, the volume resistivity of the inner layer is preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, preferably 1 × 10 ⁹ to 1 × 10 ¹² Ωcm, regardless of the presence or absence of the charge eliminating means. If the volume resistivity of the inner layer is 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, the toner scatters around the image due to electrostatic repulsion between the toners and the fringe electric field near the image edge. (Blur) The problem is less likely to occur.

Here, the volume resistivity can be measured according to JIS K6991 using a circular electrode (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). A method for measuring the volume resistivity will be described with reference to the drawings. FIG. 2 is a schematic plan view (a) and a schematic cross-sectional view (b) showing an example of a circular electrode. The circular electrode shown in FIG. 2 includes a first voltage application electrode A ′ and a second voltage application electrode B ′. The first voltage application electrode A ′ has a cylindrical electrode part C ′ and a cylindrical shape having an inner diameter larger than the outer diameter of the cylindrical electrode part C ′ and surrounding the cylindrical electrode part C ′ at a constant interval. Ring-shaped electrode portion D ′. The semiconductive belt 1 is sandwiched between the cylindrical electrode portion C ′ and ring-shaped electrode portion D ′ and the second voltage application electrode B ′ in the first voltage application electrode A ′, and the first voltage application electrode A ′. The current I (A) that flows when the voltage V (V) is applied between the cylindrical electrode portion C ′ and the second voltage application electrode B ′ is measured, and the volume resistance of the semiconductive belt 1 is calculated by the following equation. The rate ρv (Ωcm) can be calculated. Here, in the following formula, t represents the thickness of the semiconductive belt 1.
Formula: ρv = 19.6 × (V / I) × t

(Surface micro hardness)
In the semiconductive belt of the present invention, the surface microhardness of the outer layer is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less. Since the surface microhardness of the outer layer is 20 or less, special paper with uneven surfaces such as colored paper and embossing tends to be used, and the followability to such paper is improved. Toner transferability can be improved. In particular, there is a very precise correlation between the surface microhardness of the outer layer and the level of occurrence of the holocharacter. This surface microhardness causes deformation of the transfer surface (surface layer) due to the pressing force of the bias roller. Since the pressing force concentrated on the conductive toner is dispersed, the toner does not aggregate more effectively, and image quality defects such as a holocharacter in which the line image is lost do not occur. Also,

The surface microhardness can be determined by a method of measuring how much the indenter has entered the sample. A method for measuring the surface microhardness will be described. 3 is a schematic cross-sectional view showing the measurement principle of the surface microhardness of the surface layer. In FIG. 3, 10 represents the surface layer surface, 11 represents a needle-like indenter, and arrow L is applied to the needle-like indenter 11. It means load.
When measuring the surface microhardness, the tip of the needle-shaped indenter 11 having a predetermined shape is pressed to the outermost surface portion of the surface layer surface 10 until the load L (mN) is changed from the load 0 to the predetermined load P. When the depth of penetration of the needle-like indenter 11 into the surface layer 10 in the vertical direction is D (μm), the surface microhardness DH is expressed by the following equation.
Formula: DH≡αP / D ²
Here, α is a constant depending on the shape of the indenter, and α = 3.8854 (used indenter: in the case of a triangular pyramid indenter).

  This surface microhardness is the hardness obtained from the excessive weight and indentation depth in the process of indenting the indenter, and represents the strength characteristics of the material including not only plastic deformation of the sample but also elastic deformation. is there. In addition, the measurement area is very small, and more accurate hardness measurement is possible within a range close to the toner particle diameter.

The surface microhardness of the surface layer was determined by the following method. A sheet of material (laminate material of outer layer and inner layer) constituting the transfer surface is cut into about 5 mm square, and the small piece is fixed to the glass plate with an instantaneous adhesive. The surface microhardness of the surface of this sample is measured using an ultra micro hardness meter DUH-201S (manufactured by Shimadzu Corporation). The measurement conditions are as follows.
Measurement environment: 23 ° C, 55% RH
Working indenter: Triangular pyramid indenter test mode: 3 (soft material test)
Test load: 0.70 gf
Load speed: 0.0145 gf / sec
Holding time: 5 sec

  When the semiconductive belt of the present invention has a low surface microhardness of the outer layer and a high volume resistivity of the outer layer, the line image is effectively lost when used in an electrophotographic image forming apparatus. Character quality) and image quality defects such as toner scattering (blur) do not occur, and high-quality transfer image quality can be stably obtained.

  In the semiconductive belt of the present invention, the Young's modulus of the inner layer is preferably 1000 MPa or more, preferably 2000 MPa or more, more preferably 2500 MPa or more, and further preferably 3000 MPa or more.

The relationship between the Young's modulus of the inner layer and the amount of displacement of the belt due to disturbance (load fluctuation) during driving of the belt can be expressed by the following equation.
Formula: Δl = P · l · α / (t · w · E)
Where Δl: belt displacement (μm)
P: Load (N)
l: Belt length between two tension rolls (mm)
α: Coefficient t: Belt thickness (mm)
w: Belt width (mm)
E: represents the Young's modulus (N / mm ² ) of the belt material.

  As described above, the belt expansion / contraction (displacement amount) due to disturbance (load fluctuation) during belt driving is inversely proportional to the Young's modulus and thickness of the belt material. When an inner layer having a high Young's modulus (1000 MPa or more) is used, the amount of displacement of the belt due to disturbance (load fluctuation) during driving of the belt is reduced, belt deformation due to stress during driving is reduced, and good image quality is stably obtained. be able to. However, as the thickness of the belt increases, the amount of deformation of the outer surface of the belt at the belt bending portion such as the drive system roll increases, and a good image quality may not be obtained. Further, the deformation amount between the outer side and the inner side of the belt increases, and there may be a problem that the belt breaks due to local repeated stress.

  The thickness of the semiconductive belt of the present invention is preferably 0.05 to 0.5 mm in total thickness, more preferably 0.05 to 0.3 mm, and 0.06 to 0.2 mm. More preferably. If it is less than 0.05 mm, there may be a problem that the belt circumferential length changes due to belt tension. Further, when the belt thickness exceeds 0.5 mm, the belt surface is greatly deformed at the roll bending portion, so that a problem such as a crack on the surface may occur.

  Further, the thickness of the outer layer is preferably 5 to 80% of the total thickness of the belt, more preferably 10 to 50%, and in the above range, the constituent resin composition of the inner layer (for example, polyimide resin) Without affecting the pressure, the pressing force concentrated on the toner on the semiconductive belt is dispersed. For this reason, the toner does not aggregate, and image quality defects such as holocharacters in which the line image is lost do not occur. Further, when the Young's modulus of the resin composition of the inner layer is 1000 MPa or more (preferably 2000 MPa or more) and a high Young's modulus, the mechanical properties as a semiconductive belt can be satisfied.

  The semiconductive belt of the present invention has at least an outer layer and an inner layer as described above, but may contain additives other than the described conductive agent. Further, in addition to the outer layer as the surface layer and the inner layer as the base material, an intermediate layer may be further added to form a multilayer so long as the effects of the present invention are not impaired.

  Since the formation of the semiconductive belt of the present invention is endless, it can be formed by an appropriate connection method such as an adhesive method using an adhesive at the film end or a seamless belt. . The seamless belt has an advantage that an arbitrary portion can be set as the rotation start position without any change in the thickness of the joint, and a control mechanism for the rotation start position can be omitted.

  The inner layer and the outer layer are formed, for example, by developing the polyamic acid solution obtained by polymerizing the tetracarboxylic dianhydride having the wholly aromatic skeleton and the diamine component in an appropriate manner. The developed layer can be dried and formed into a film, and the molded product can be heat treated to convert the polyamic acid into an imide. The outer layer is a thermoplastic containing a thermoplastic elastomer. The resin composition is extruded on the surface of the inner layer into a belt shape to obtain a two-layer belt. After forming into a belt shape, there is a method of obtaining a two-layer belt by a method such as laminating on the surface of the inner layer and heating, in the case of a method such as laminating and heating, the adhesive layer is It can also be provided.

  The semiconductive belt of the present invention having the above-described configuration can be used as an intermediate transfer belt and a paper transport belt used in an electrophotographic image forming apparatus such as an electrophotographic copying machine or a laser printer.

<Electrophotographic image forming apparatus>
The electrophotographic image forming apparatus of the present invention is not particularly limited except that the semiconductor belt of the present invention is applied. For example, normal monocolor image formation in which only a single color toner is accommodated in the developing device. A color image forming apparatus that sequentially repeats primary transfer of toner images carried on an image carrier such as a photosensitive drum to an intermediate transfer member, and a plurality of image carriers having developing units for each color as intermediate transfer members Any of a tandem color image forming apparatus and the like arranged in series on the top may be used.

  As a first aspect of the image forming apparatus of the present invention, the semiconductive belt of the present invention is used as an intermediate transfer belt. Further, as a second aspect of the image forming apparatus of the present invention, it is possible to use the semiconductive belt of the present invention as a paper conveying belt. Furthermore, it is preferable that the electrophotographic image forming apparatus of the present invention is provided with a static elimination means for eliminating the charge of a semiconductive belt applied as an intermediate transfer member or a paper conveying belt.

  As an example, FIG. 4 shows a schematic diagram of a color image forming apparatus that repeats primary transfer sequentially using the semiconductive belt of the present invention as an intermediate transfer belt. FIG. 4 is a schematic diagram for explaining a main part of the electrophotographic image forming apparatus of the present invention. The image forming apparatus includes a photosensitive drum 21 as an image carrier, an intermediate transfer belt 22 as an intermediate transfer member, a bias roller 23 (second transfer means) as a transfer electrode, and a sheet for supplying recording paper as a transfer medium. Tray 24, developing device 25 using Bk (black) toner, developing device 26 using Y (yellow) toner, developing device 27 using M (magenta) toner, developing device 28 using C (cyan) toner, intermediate transfer body cleaner 29, peeling Claw 33, belt rollers 41, 43 and 44, backup roller 42, conductive roller 45 (first transfer means), electrode roller 46, cleaning blade 51, recording paper 61, pickup roller 62, and feed roller 63. Become.

  In FIG. 4, the photosensitive drum 1 rotates in the direction of arrow A, and its surface is uniformly charged by a charging device (not shown). An electrostatic latent image of the first color (for example, Bk) is formed on the charged photosensitive drum 21 by image writing means such as a laser writing device. The electrostatic latent image is developed with toner by the black developing device 25 to form a visualized toner image T. The toner image T reaches the primary transfer portion where the conductive roller 45 (first transfer means) is disposed by the rotation of the photosensitive drum 21, and an electric field having a reverse polarity is applied to the toner image T from the conductive roller 45. Thus, the toner image T is primarily transferred by the rotation of the intermediate transfer belt 22 in the direction of arrow B while being electrostatically attracted to the intermediate transfer belt 22.

Thereafter, similarly, a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the intermediate transfer belt 22 to form a multiple toner image.
The multiple toner image transferred to the intermediate transfer belt 22 reaches the secondary transfer portion where the bias roller 23 (second transfer means) is installed by the rotation of the intermediate transfer belt 2. The secondary transfer unit includes a bias roller 23 installed on the surface side on which the toner image of the intermediate transfer belt 22 is carried, a backup roller 42 disposed so as to face the bias roller 23 from the back side of the intermediate transfer belt 22, and It is composed of an electrode roller 46 that rotates in pressure contact with the backup roller 42.

  The recording paper 61 is picked up one by one from the recording paper bundle stored in the paper tray 24 by the pickup roller 62, and is fed at a predetermined timing between the intermediate transfer belt 22 and the bias roller 23 of the secondary transfer portion by the feed roller 63. It is sent by. The toner image carried on the intermediate transfer belt 22 is transferred to the fed recording paper 61 by the pressure contact conveyance by the bias roller 23 and the backup roller 42 and the rotation of the intermediate transfer belt 22.

  The recording paper 61 onto which the toner image has been transferred is peeled from the intermediate transfer belt 22 by operating the peeling claw 33 in the retracted position until the primary transfer of the final toner image is completed, and is conveyed to a fixing device (not shown). The toner image is fixed by heat treatment to be a permanent image. The intermediate transfer belt 22 having completed the transfer of the multiple toner image to the recording paper 61 is prepared for the next transfer by removing residual toner by an intermediate transfer body cleaner 29 provided downstream of the secondary transfer portion. The bias roller 23 is attached so that a cleaning blade 51 made of polyurethane or the like is always in contact therewith, and foreign matters such as toner particles and paper dust adhered by transfer are removed.

In the case of transfer of a single color image, the primary transferred toner image T is immediately secondarily transferred and conveyed to the fixing device. In the case of transfer of a multicolor image by superimposing a plurality of colors, the toner image of each color is transferred to the primary transfer unit. Therefore, the rotation of the intermediate transfer belt 22 and the photosensitive drum 21 is synchronized so that the toner images of the respective colors do not shift so as to match exactly. In the secondary transfer portion, an output pressure (transfer voltage) having the same polarity as the polarity of the toner image is applied to the electrode roller 46 that is in pressure contact with the backup roller 42 that is disposed opposite to the bias roller 23 via the intermediate transfer belt 22. Then, the toner image is transferred to the recording paper 61 by electrostatic repulsion. Further, the charge on the intermediate transfer belt 22 is neutralized by a static elimination roll 50 (static elimination means). As the static elimination roll 50, for example, an elastic roll (for example, an epichlorohydrin rubber roll with carbon black dispersion) in which a conductive agent is dispersed to adjust the volume resistance to a range of 10 ⁵ to 10 ¹⁰ Ω can be used.

Furthermore, the first aspect of the image forming apparatus of the present invention includes an intermediate transfer belt which is the semiconductive belt of the present invention, and includes, for example, a developing device 85 for four colors (black, yellow, magenta, cyan). The present invention can be applied to a tandem color image forming apparatus in which the photoreceptors 79 for the respective colors are arranged on an intermediate transfer member (intermediate transfer belt) 86. FIG. 5 is a schematic diagram for explaining a main part of a tandem type image forming apparatus to which the present invention is applied. By providing the intermediate transfer belt of the present invention, a high-quality transfer image can be obtained. Specifically, in FIG. 5, a charging roll 83 (charging device) that uniformly charges the surface of the photoreceptor 79, a laser generator 78 (exposure device) that exposes the surface of the photoreceptor 79 to form an electrostatic latent image, and a photoreceptor. 79 A latent image formed on the surface is developed with a developer, and a developing device 85 (developing device) for forming a toner image, and a photoconductor cleaner 84 (cleaning device) for removing toner, dust and the like attached to the photoconductor. The fixing roller 72 for fixing the toner image on the transfer material can be optionally provided by a known method as necessary. The charge on the intermediate transfer member 86 is neutralized by a neutralizing roll (static neutralizing means) 88.
Even in the tandem image forming apparatus having the above-described configuration, high-quality transfer image quality can be stably obtained.

  The image forming apparatus according to the first aspect using the semiconductive belt of the present invention as the intermediate transfer belt has been described above. However, the image forming according to the second aspect using the semiconductive belt of the present invention as the paper conveying belt is described. Similar effects can be obtained in the apparatus.

  Furthermore, when the semiconductive belt of the present invention is incorporated and used as an intermediate transfer belt or transfer / conveying belt in an image forming apparatus, it is preferable to use a spherical toner. By using spherical toner as the toner, the material constituting the transfer surface has a low surface hardness and a high volume resistance, thereby obtaining a high-quality transfer image quality free from image quality defects (holocharacter, blur, color registration). be able to.

However, the spherical toner means that its shape factor (ML ² / A) is 140 to 100. The shape factor is preferably 130 to 100 or less, and more preferably 120 to 100 or less. When this average shape factor (ML ² / A) is larger than 140, the transfer efficiency is lowered, and the deterioration of the image quality of the print sample can be visually confirmed.

Here, the shape factor (ML ² / A) is a factor defined by the following equation.
Formula: (ML ² / A) = (absolute maximum length of toner particles) ² / (projected area of toner particles) × (π / 4) × 100

  The absolute maximum length of the toner particles and the projected area of the toner particles are measured using a Luzex image analyzer (FT manufactured by Nireco Co., Ltd.), an optical microscope image of the toner dispersed on the slide glass, This was carried out by taking the image into a Luzex image analyzer through a camera and processing the image.

  The spherical toner contains at least a binder resin and a colorant. The spherical toner may preferably use 2 to 12 μm particles, more preferably 3 to 9 μm particles.

  Binder resins include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, and methyl acrylate. , Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl Homopolymers and copolymers of vinyl ethers such as methyl ether, vinyl ethyl ether, and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone can be exemplified. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. , Polyethylene, polypropylene and the like. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can also be mentioned.

  Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The spherical toner may be subjected to internal addition treatment or external addition treatment with a known additive such as a charge control agent, a release agent, and other inorganic fine particles. Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination.

As other inorganic fine particles, small-diameter inorganic fine particles having an average primary particle size of 40 nm or less are used for the purpose of powder flowability, charge control, etc., and if necessary, larger diameters are used to reduce adhesion. Inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used. Examples thereof include silica, alumina, titania, metatitanic acid, zinc oxide, zirconia, magnesia, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, and strontium titanate.
In addition, the surface treatment of the small-diameter inorganic fine particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

  The spherical toner is not particularly limited by the production method, and can be obtained by a known method. Specifically, for example, a kneading and pulverizing method in which a binder resin and a colorant and, if necessary, a release agent and a charge control agent are kneaded, pulverized and classified, and particles obtained by the kneading and pulverizing method are mechanically impacted. Method of changing shape by force or heat energy, emulsion polymerization of binder resin polymerizable monomer, dispersion of formed dispersion, colorant, release agent and charge control agent as required Liquid emulsion, agglomeration, heat fusion to obtain spherical toner, emulsion polymerization aggregation method, polymerizable monomer for obtaining binder resin, colorant, release agent if necessary, charge control agent A suspension polymerization method in which a solution such as a suspension is polymerized by suspending in an aqueous solvent, a binder resin and a colorant, and a release agent and a charge control agent as necessary are suspended in an aqueous solvent and granulated. Examples thereof include a dissolution suspension method. In addition, a manufacturing method may be performed in which the spherical toner obtained by the above method is used as a core, and aggregated particles are further adhered and heat-fused to give a core-shell structure. When the external additive is added, it can be produced by mixing the spherical toner and the external additive with a Henschel mixer or a V blender. In addition, when the spherical toner is manufactured by a wet method, it can be externally added by a wet method.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example 1>
(Formation of inner layer material)
-Preparation of polyamic acid solution (A)-
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) are combined in a ratio of 2: 1 to obtain a diamine. As a component, N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 4,4′-diaminodiphenyl ether (DDE) (solid content 20% by mass) was dried acidic carbon black (SPECIAL BLACK4 (manufactured by Degussa). , PH 3.0, volatile content: 14.0% by mass) with respect to 100 parts by mass of the polyimide resin solid content to 24 parts by mass, and using a collision type disperser (Geanus PY made by Sinus), pressure in 200 MPa, the minimum area collide after two split 1.4 mm ^2, by passing five times a path divided into two again, and mixed, the surface To obtain a carbon black-containing polyamic acid solution (A) of use.

The polyamic acid solution containing carbon black (A) is applied to the inner surface of the cylindrical mold to a thickness of 0.4 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm. However, after applying hot air of 60 ° C. for 30 minutes from the outside of the mold, it was heated at 150 ° C. for 60 minutes, returned to room temperature, peeled off from the mold, coated on the metal core, and 2 ° C. up to 360 ° C. The temperature was raised at a rate of temperature rise / minute, and further heated at 360 ° C. for 30 minutes to remove the solvent, remove dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature, and the film was peeled from the mold to obtain a target polyimide film. The thickness of the film was 0.08 mm. The Young's modulus of this resin belt was 2500 MPa, and the volume resistivity at an applied voltage of 100 V was 5 × 10 ¹⁰ Ωcm.

(Formation of outer layer material)-
As materials for the outer layer, 100 parts by mass of a polyamide-based thermoplastic elastomer (trade name: Daiamid-E47-S1: manufactured by Daicel Hyurs Co., Ltd.) and an epoxidized diene block copolymer (trade name: Epofriend A1020: Daicel Chemical Industries, Ltd.) 20 parts by mass and carbon black (trade name: Printex 140U (pH 4.5, volatile content 5% by mass): Degussa Japan) 14 parts by mass are dispersed and kneaded with a twin screw extruder. Using the resin composition, a resin belt having a thickness of 0.15 mm was produced using a single screw extruder. This resin belt had a volume resistivity of 5 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface microhardness was 18.

(Formation of a two-layer belt)
The inner layer material / outer layer material is pressed against a cylindrical mold and heated under a pressure of 5.5 kg / cm ^{2 at} a temperature of 150 ° C. for 60 minutes to obtain a two-layer belt. The thickness of each layer of this semiconductive belt was 0.12 mm for the outer layer and 0.08 mm for the inner layer.

<Example 2>
(Inner & outer material)
The same material as in Example 1 was used as the inner layer material, and 100 parts by mass of a thermoplastic elastomer containing a polyester component (trade name: Elastage ES5000A: manufactured by Tosoh Corp.) and an epoxidized diene block copolymer ( Product name: Epofriend A1020: manufactured by Daicel Chemical Industries, Ltd.) 16 parts by mass and carbon black (trade name: Printex 140U (pH 4.5, volatile content 5% by mass): manufactured by Degussa Japan) 16 parts by mass, A resin belt having a thickness of 0.15 mm was produced by using a resin composition obtained by dispersing and kneading the mixture with a twin screw extruder using a single screw extruder. This resin belt had a volume resistivity of 8 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface microhardness was 10.

(Formation of a two-layer belt)
The inner layer material / adhesive layer / outer layer material is pressed against a cylindrical mold and heated under a pressure of 5.5 kg / cm ^{2 at} a temperature of 150 ° C. for 60 minutes to obtain a two-layer belt. As the adhesive layer, urethane adhesive (Nipporan 2301 manufactured by Nippon Polyurethane Co., Ltd.) was used with a thickness of 0.005 mm. The thickness of each layer of this semiconductive belt was 0.12 mm for the outer layer and 0.08 mm for the inner layer. there were

<Example 3>
(Formation of inner layer material)
-Preparation of polyamic acid solution (B)-
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) Euvanis A (solid content 20% by mass), dried acidic carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0% by mass) with respect to 100 parts by mass of polyimide resin solid content, Add to 26 parts by mass, and use a collision type disperser (GeanusPY made by Seanas), collide after splitting into two parts with a pressure of 200 MPa and a minimum area of 1.4 mm ² , and pass through the path that splits again into two parts 5 times. And mixed to obtain a polyamic acid solution (B) containing carbon black for a substrate.

The polyamic acid solution containing carbon black (B) is applied to the inner surface of the cylindrical mold to 0.4 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm. However, after applying hot air of 60 ° C. for 30 minutes from the outside of the mold, it was heated at 150 ° C. for 60 minutes, returned to room temperature, peeled off from the mold, coated on the metal core, and 2 ° C. up to 360 ° C. The temperature was raised at a rate of temperature rise / minute, and further heated at 400 ° C. for 30 minutes to remove the solvent, remove the dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature, and the film was peeled from the mold to obtain a target polyimide film. The thickness of the film was 0.08 mm. The Young's modulus of this resin belt was 3800 MPa, and the volume resistivity at an applied voltage of 100 V was 5 × 10 ¹⁰ Ωcm.

(Formation of outer layer material)
As an outer layer material, 100 parts by mass of a polyamide-based thermoplastic elastomer (trade name: Daiamid-E40-S3: manufactured by Daicel Hyurs Co., Ltd.) and an epoxidized diene block copolymer (trade name: Epofriend A1020: Daicel Chemical Industries, Ltd.) )) 10 parts by mass and carbon black (trade name: Printex 140U (pH 4.5, volatile content 5% by mass): Degussa Japan Co., Ltd.) 14 parts by mass, dispersed and kneaded with a twin screw extruder Using a product, a resin belt having a thickness of 0.15 mm was produced using a single screw extruder. This resin belt had a volume resistivity of 6 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface microhardness was 14.

(Formation of a two-layer belt)
A two-layer belt was formed by the same method as in Example 1.

<Comparative Example 1>
-Preparation of polyamic acid solution (C)-
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) (Uwanisu S Solid carbon content (20% by mass) and dried carbon black (acetylene black (pH 5.7, manufactured by Denki Kagaku Kogyo Co., Ltd., volatile content: 0.89%) are 13 parts by mass with respect to 100 parts by mass of polyimide resin solids. Then, using a collision type disperser (GeanusPY made by Seanas), with a pressure of 200 MPa and a minimum area of 1.4 mm ² , collided after being divided into ^two , and again passing through the path divided into two and mixed five times. Thus, a polyamic acid solution (C) containing carbon black for a substrate was obtained.

The polyamic acid solution containing carbon black (C) is applied on the inner surface of the cylindrical mold to a thickness of 0.5 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm. However, after applying hot air of 60 ° C. for 30 minutes from the outside of the mold, it was heated at 150 ° C. for 60 minutes, returned to room temperature, peeled off from the mold, coated on the metal core, and 2 ° C. up to 400 ° C. The temperature was raised at a rate of temperature rise / minute, and further heated at 400 ° C. for 30 minutes to remove the solvent, remove the dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature, and the film was peeled from the mold to obtain a target polyimide film. The thickness of the film was 0.08 mm. The Young's modulus of this resin belt was 6000 MPa, and the volume resistivity at an applied voltage of 100 V was 8 × 10 ¹⁰ Ωcm. The surface microhardness was 38.

  In this way, a single layer belt was obtained.

<Comparative example 2>
-Preparation of polyamic acid solution (C)-
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) Euvanis A (solid content 20% by mass)) and dried carbon black (acetylene black (pH 5.7, manufactured by Denki Kagaku Kogyo Co., Ltd., volatile content 0.89% by mass) with respect to 100 parts by mass of polyimide resin solid content, Add to 15 parts by mass, use collision type disperser (GeanusPY made by Seanus), pressure 200 MPa, minimum area 1.4 mm ² , collide after 2 divisions, and pass again through 2 paths 5 times And mixed to obtain a polyamic acid solution (C) containing carbon black.

The polyamic acid solution containing carbon black (C) is applied on the inner surface of the cylindrical mold to a thickness of 0.5 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm. However, after applying hot air of 60 ° C. for 30 minutes from the outside of the mold, it was heated at 150 ° C. for 60 minutes, returned to room temperature, peeled off from the mold, coated on the metal core, and 2 ° C. up to 400 ° C. The temperature was raised at a rate of temperature rise / minute, and further heated at 400 ° C. for 30 minutes to remove the solvent, remove the dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature, and the film was peeled from the mold to obtain a target polyimide film. The thickness of the film was 0.08 mm. The Young's modulus of this resin belt was 3800 MPa, and the volume resistivity at an applied voltage of 100 V was 8 × 10 ¹⁰ Ωcm. The surface microhardness was 26.

  In this way, a single layer belt was obtained.

<Comparative Example 3>
100 parts by mass of a polyamide-based thermoplastic elastomer (trade name: Daiamid-PAE X442: manufactured by Daicel Hyurs Co., Ltd.) and 13 parts by mass of Ketchen Black EC (Lion Aguso Co., Ltd. pH 9.0, volatile content 1.5% by mass) Using a resin composition dispersed and kneaded with a twin screw extruder, a resin belt having a thickness of 0.2 mm, a width of 350 mm, and a circumferential length of 264 mm was produced using a single screw extruder. The Young's modulus of this resin belt was 900 MPa, and the volume resistivity at an applied voltage of 100 V was 3 × 10 ¹⁰ Ωcm. The surface microhardness was 18.

  In this way, a single layer belt was obtained.

<Comparative example 4>
Using the material used in Comparative Example 1 as the inner layer material and the material used in Comparative Example 3 as the outer layer material, a two-layer belt was formed by the same method as in Example 1.

<Evaluation>
About the semiconductive belts obtained in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, and 4, surface characteristics (surface microhardness, volume resistivity) of the outer layer as the surface layer, The inner layer characteristics (Young's modulus, volume resistivity), transfer image quality (blur, holocharacter, color registration, white spot), and embossed paper runnability were evaluated. These results are shown in Table 1 below.

(Volume resistivity)
As for the surface layer of the obtained semiconductive belt, the circular electrode shown in FIG. 2 (HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd .: outer diameter φ16 mm of the cylindrical electrode portion C, inner diameter of the ring-shaped electrode portion D) A voltage of 100 (V) is applied between the cylindrical electrode portion C ′ of the first voltage application electrode A ′ and the second voltage application electrode B ′, and the current value after 30 seconds. I asked more. A voltage of 100 V was applied in a 22 ° C./55% RH environment, and the current value after 10 seconds was calculated.

(Surface micro hardness)
About the surface layer of the obtained semiconductive belt, it measured on condition of the following using the apparatus (Ultra micro hardness meter DUH-201S (made by Shimadzu Corporation)) shown in FIG.
Measurement environment: 23 ° C, 55% RH
Working indenter: Triangular pyramid indenter test mode: 3 (soft material test)
Test load: 0.70 gf
Load speed: 0.0145 gf / sec
Holding time: 5 sec

(Young's modulus)
In accordance with JIS K6251, a semiconductive belt was punched into a JIS No. 3 shape and subjected to a tensile test. A tangent line was drawn to the curve in the initial strain region of the obtained stress / strain curve, and the Young's modulus was obtained from the slope.

(Evaluation of transfer image quality)
The obtained semiconductive belt was evaluated for transfer image quality using Fuji Xerox Co., Ltd. Docu Color 1255CP.

(Holo character evaluation)
The occurrence of holo-characters was evaluated according to the following criteria.
◎: No image quality problem ○: Slight occurrence, few image quality problems ×: Image quality problem

(Blur evaluation)
The occurrence of blur was evaluated according to the following criteria.
◎: No blurring ○: Bluring is slight and there is no problem in image quality ×: Bluring occurs and there is a problem in image quality

(Evaluation of color registration (color shift))
The occurrence of misregistration was evaluated according to the following criteria after 10000 sheets of normal and normal A4 size copier plain paper (75 g / m ² ).
◎: No image quality problem ○: Little occurrence, few image quality problems ×: Image quality problem

(Embossed paper runability evaluation)
The image quality was evaluated when a halftone of 30% magenta was copied by running an embossed paper with a step of 50 μm, and evaluated according to the following criteria.
○: No significant image quality problem ×: Image quality problem

(Evaluation of white spots)
After 3000 copies of postcards were continuously copied, the occurrence of white spots when copying a halftone of 30% magenta was evaluated according to the following criteria.
○: No white spot occurs ×: White spot occurs and there is a problem in image quality

  FIG. 6 is an explanatory diagram showing the occurrence of white spots when a halftone of 30% magenta is copied after continuously copying 3000 postcards. When the surface resistivity is 1.1 digits (logΩ / □) lower than the surrounding surface resistivity by continuously running paper (postcard) in a low temperature and low humidity environment of 10 ° C. and 15% RH, the above half In the tone (30% magenta), whitening occurs.

FIG. 7 is a schematic diagram for explaining the decrease in the surface resistivity of the secondary transfer portion of the intermediate transfer member (specifically, in FIG. 4, the bias roller 23 and the pressure roller 23 that are in pressure contact with each other via the intermediate transfer belt 22). This corresponds to an enlarged view of the vicinity of the backup roller 42). This shows the state of charging of the outer peripheral surface of the intermediate transfer belt 22 and the surface of the recording paper 61 on the side in contact with the outer peripheral surface of the intermediate transfer belt 22 immediately after the secondary transfer.
As can be seen from FIG. 7, immediately after the secondary transfer, the outer peripheral surface of the intermediate transfer belt 22 is charged to the plus side, and the surface of the recording paper 61 on the intermediate transfer belt 22 side is charged to the minus side. A peeling discharge is generated between the belt 22 and the recording paper 61 and the surface of the intermediate transfer belt 22 is deteriorated, whereby the surface resistance of the outer peripheral surface of the intermediate transfer belt 22 is lowered.

From the results in Table 1, the semiconductive belts of Examples 1 to 3 of the present invention were free from image quality defects and could stably obtain excellent image quality over a long period of time.
On the other hand, in Comparative Example 1, the surface hardness of the transfer surface was high, and a holo character image quality defect occurred. In Comparative Example 2, since the surface hardness of the transfer surface was soft, the occurrence of image quality defects in holo-chara was small and acceptable in terms of image quality, but there was a problem in the runnability of embossed paper. Comparative Example 3 had a problem of poor color registration due to its low Young's modulus. Further, Comparative Examples 1 to 3 had a problem that white spots occurred after 3000 postcards were copied continuously. In the evaluation of the color registration of Comparative Example 4, there was no problem in image quality at the initial stage, but image quality problems occurred after 10,000 sheets of A4 size copier plain paper (75 g / m ² ).

<Example 4>
(Formation of inner layer material)
A resin belt similar to that in Example 1 was produced as the inner layer material.

(Formation of outer layer material)
As an outer layer material, 100 parts by mass of a polyamide-based thermoplastic elastomer (trade name: Daiamid-E47-S1: manufactured by Daicel Hyurs Co., Ltd.) and an epoxidized diene block copolymer (trade name: Epofriend A1020: Daicel Chemical Industries, Ltd.) )) 20 parts by mass and carbon black (trade name: Printex 140U (pH 4.5, volatile content 5% by mass): Degussa Japan Co., Ltd.) 6 parts by mass, dispersed and kneaded with a twin screw extruder, resin Using the composition, a resin belt having a thickness of 0.15 mm was produced using a single screw extruder. This resin belt had a volume resistivity of 1 × 10 ¹³ Ωcm at an applied voltage of 100V. The surface microhardness was 17.

(Formation of a two-layer belt)
The inner layer material / outer layer material is pressed against a cylindrical mold and heated under a pressure of 5.5 kg / cm ^{2 at} a temperature of 150 ° C. for 60 minutes to obtain a two-layer belt. The thickness of each layer of this semiconductive belt was 0.12 mm for the outer layer and 0.08 mm for the inner layer.

<Example 5>
(Inner & outer material)
The same material as in Example 1 was used as the inner layer material, and 100 parts by mass of a thermoplastic elastomer containing a polyester component (trade name: Elastage ES5000A: manufactured by Tosoh Corp.) and an epoxidized diene block copolymer ( Product name: Epofriend A1020: manufactured by Daicel Chemical Industries, Ltd.) 16 parts by mass and carbon black (trade name: Printex 140U (pH 4.5, volatile content 5% by mass): manufactured by Degussa Japan) 6 parts by mass, The resin composition was dispersed and kneaded with a twin screw extruder, and a resin belt with a thickness of 0.15 mm was prepared using a single screw extruder. This resin belt had a volume resistivity of 2 × 10 ¹³ Ωcm at an applied voltage of 100V. The surface microhardness was 9.

(Formation of a two-layer belt)
The inner layer material / adhesive layer / outer layer material is pressed against a cylindrical mold and heated under a pressure of 5.5 kg / cm ^{2 at} a temperature of 150 ° C. for 60 minutes to obtain a belt having a two-layer structure. As the adhesive layer, urethane adhesive (Nipporan 2301 manufactured by Nippon Polyurethane Co., Ltd.) was used with a thickness of 0.005 mm. The thickness of each layer of this semiconductive belt was 0.12 mm for the outer layer and 0.08 mm for the inner layer. there were.

<Example 6>
(Formation of inner layer material)
As the inner layer material, a resin belt similar to that in Example 3 was produced.

(Formation of outer layer material)
As an outer layer material, 100 parts by mass of a polyamide-based thermoplastic elastomer (trade name: Daiamid-E40-S3: manufactured by Daicel Hyurs Co., Ltd.) and an epoxidized diene block copolymer (trade name: Epofriend A1020: Daicel Chemical Industries, Ltd.) )) 10 parts by mass and carbon black (trade name: Printex 140U (pH 4.5, volatile content 5% by mass): Degussa Japan Co., Ltd.) 6 parts by mass, dispersed and kneaded with a twin screw extruder Using this product, a 0.15 mm thick resin belt was produced using a single screw extruder. This resin belt had a volume resistivity of 2 × 10 ¹³ Ωcm at an applied voltage of 100V. The surface microhardness was 14.

(Formation of a two-layer belt)
A two-layer belt was formed in the same manner as in Example 4.

<Evaluation>
The semiconductive belts obtained in Examples 4, 5, and 6 were evaluated in the same manner as in Example 1. These results are shown in Table 2. However, in evaluating the transfer image quality, Fuji Xerox Co., Ltd. Docu Color 1255CP (remodeling machine) equipped with an epichlorohydrin rubber roll dispersed with carbon black was used as a charge eliminating roll for removing the semiconductive belt after the secondary transfer.

  From the results of Table 2, the semiconductive belts of Examples 4 to 6 of the present invention were free from image quality defects and could stably obtain excellent image quality over a long period of time. In particular, it can also be seen that by applying to an image forming apparatus provided with a charge-removing roll, blurring can be prevented and continuously excellent image quality can be realized over a long period of time.

<Example 7>
(Formation of inner layer material)
As an inner layer material, 100 parts by mass of polyvinylidene fluoride resin (manufactured by Kureha Chemical Industry Co., Ltd .: trade name “# 850”) as a conductive agent, oxidized carbon black (trade name: Printex 140U (pH 4.5, volatile content 5) (Mass%): Degussa Japan Co., Ltd.) 16 parts by mass was added, and the resin composition was dispersed and kneaded with a twin screw extruder, and further a thickness of 0.15 mm using a single screw extruder. A resin belt was produced. This resin belt had a volume resistivity of 1 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The Young's modulus was 1900 MPa.

(Formation of outer layer material)
As an outer layer material, a resin belt similar to that in Example 4 was produced.

(Formation of a two-layer belt)
The inner layer material / outer layer material is pressed against a cylindrical mold and heated under a pressure of 5.5 kg / cm ^{2 at} a temperature of 150 ° C. for 60 minutes to obtain a two-layer belt. The thickness of each layer of this semiconductive belt was 0.15 mm for the outer layer and 0.08 mm for the inner layer.

<Example 8>
(Inner & outer material)
The same material as in Example 7 was used as the inner layer material, and the same material as in Example 5 was used as the outer layer material.

(Formation of a two-layer belt)
The inner layer material / adhesive layer / outer layer material is pressed against a cylindrical mold and heated under a pressure of 5.5 kg / cm ^{2 at} a temperature of 150 ° C. for 60 minutes to obtain a two-layer belt. As the adhesive layer, urethane adhesive (Nipporan 2301 manufactured by Nippon Polyurethane Co., Ltd.) was used with a thickness of 0.005 mm. The thickness of each layer of this semiconductive belt was 0.15 mm for the outer layer and 0.08 mm for the inner layer. there were.

<Example 9>
(Formation of inner layer material)
As an inner layer material, 100 parts by mass of vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Kureha Chemical Industry Co., Ltd .: trade name “# 2300”) as a conductive agent, oxidized carbon black (trade name: Printex 140U (pH 4) .5, volatile content 5% by mass): Degussa Japan Co., Ltd.) 15 parts by mass are added, and the resin composition is dispersed and kneaded with a twin screw extruder, and further, using a single screw extruder, A resin belt having a thickness of 0.15 mm was produced. This resin belt had a volume resistivity of 5 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The Young's modulus was 1500 MPa.

(Formation of outer layer material)
As an outer layer material, a resin belt similar to that in Example 6 was produced.

(Formation of a two-layer belt)
A two-layer belt was formed in the same manner as in Example 7.

<Example 10>
(Formation of inner and outer layer materials)
As the inner layer material, the same material as in Example 7 was used. As the outer layer material, 100 parts by mass of a polyamide-based thermoplastic elastomer (trade name: Daiamid-E47-S1: manufactured by Daicel Hyurs Co., Ltd.) and an epoxidized diene block copolymer were used. (Product name: Epofriend A1020: manufactured by Daicel Chemical Industries, Ltd.) 20 parts by mass and carbon black (Product name: Printex 140U (pH 4.5, volatile content 5% by mass): manufactured by Degussa Japan) 13 parts by mass Were dispersed and kneaded with a twin-screw extruder, and the resin composition was used to prepare a resin belt with a thickness of 0.15 mm using a single-screw extruder. This resin belt had a volume resistivity of 1 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface microhardness was 17.

(Formation of a two-layer belt)
A two-layer belt was formed in the same manner as in Example 7.

<Evaluation>
The semiconductive belts obtained in Examples 7, 8, 9, and 10 were evaluated in the same manner as in Example 1, and the results are shown in Table 3.

  From the results of Table 3, the semiconductive belts of Examples 7 to 10 of the present invention were free from image quality defects and could stably obtain excellent image quality over a long period of time. In particular, the semiconductive belts of Examples 7 to 9 can effectively prevent blurring and continuously achieve excellent image quality over a long period of time by being applied to an image forming apparatus provided with a static elimination roll. I understand that there is.

  As described above, from the examples, the semiconductive belt of the present invention is excellent in forming a nip shape at the transfer portion, and is suitable for the transfer image line image hollow (holo character), toner scattering (blur), color misregistration, etc. It can be seen that the image quality defects are remarkably small, and the change in electrical resistance with time is small, so that a high-quality transfer image quality can be stably obtained.

It is sectional drawing which shows the structure of the semiconductive belt of this invention. It is a figure which shows the measuring method of volume resistivity. It is a figure which shows the measuring method of surface micro hardness. 1 is a schematic diagram for explaining a main part of an electrophotographic image forming apparatus of the present invention. 1 is a schematic diagram for explaining a main part of an electrophotographic image forming apparatus of the present invention. FIG. 10 is an explanatory diagram illustrating a white spot occurrence state in a paper travel unit after 3000 sheets are continuously copied. It is a figure explaining the fall of the surface resistivity in the secondary transfer part of an intermediate transfer body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductive belt 2 Surface layer 3 Base material 10 Surface layer surface 11 Needle-shaped indenter 21 Photosensitive drum (image carrier)
22 Intermediate transfer belt (intermediate transfer member)
23 Bias roller (second transfer means)
24 Paper tray 25 Black developing device 26 Yellow developing device 27 Magenta developing device 28 Cyan developing device 29 Intermediate transfer member cleaner 33 Peeling claw 41 Belt roller 42 Backup roller 43 Belt roller 44 Belt roller 45 Conductive roller (first transfer means)
46 Electrode roller 50 Static elimination roll 51 Cleaning blade 61 Recording paper 62 Pickup roller 63 Feed roller 71 Toner cartridge 72 Fixing roll 73 Backup roll 74 Tension roll 75 Secondary transfer roll 76 Paper path 77 Paper tray 78 Laser generator 79 Photoconductor 80 1 Next transfer roll 81 Drive roll 82 Transfer cleaner 83 Charging roll 84 Photoconductor cleaner 85 Developer 86 Intermediate transfer member 88 Static elimination roll

Claims (11)

A semiconductive belt used in an electrophotographic image forming apparatus,
At least an outer layer and an inner layer provided on the inner peripheral surface side of the outer layer are configured,
The outer layer includes a conductive resin composition comprising (a) an epoxidized diene block copolymer and (b) a thermoplastic elastomer other than the epoxidized diene block copolymer. Characteristic semi-conductive belt.   The semiconductive belt according to claim 1, wherein the thermoplastic elastomer is selected from a polyamide-based thermoplastic elastomer and a polyester-based thermoplastic elastomer.   The semiconductive belt according to claim 1 or 2, wherein the inner layer is made of a thermoplastic resin composition having a Young's modulus of 1000 MPa or more.   The semiconductive belt according to any one of claims 1 to 3, wherein the inner layer is composed of a thermoplastic resin composition obtained by adding a conductive agent.   The semiconductive belt according to any one of claims 1 to 4, wherein the inner layer includes a fluorine-based resin. The semiconductive belt according to any one of claims 1 to 5, wherein the inner layer is composed of a thermoplastic resin composition having a volume resistivity of 1 x 10 ⁸ to 1 x 10 ¹³ Ωcm. . The semiconductive belt according to any one of claims 1 to 6, wherein each of the outer layer and the inner layer has a volume resistivity of 1 x 10 ⁸ to 1 x 10 ¹³ Ωcm. 7. The outer layer has a volume resistivity of 1 × 10 ¹³ Ωcm or more, and the inner layer has a volume resistivity of 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm. The semiconductive belt described in 1.   An electrophotographic image forming apparatus comprising the semiconductive belt according to claim 1.   The electrophotographic image forming apparatus according to claim 9, wherein the electrophotographic image forming apparatus includes an intermediate transfer body, and the semiconductive belt is provided as the intermediate transfer body.   The electrophotographic image forming apparatus according to any one of claims 9 to 10, further comprising a charge removing unit for removing charge from the semiconductive belt.

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