JP2009086190A - Endless belt and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt which contributes to the formation of a high-quality image, and to provide an image forming apparatus capable of forming a high-quality image. <P>SOLUTION: The endless belt 1 produces a depression of ≤10 μm when it undergoes a depressive load test which is performed by applying a compressive load of 2,300 g to a spherical body having a diameter of 0.7 mm. The image forming apparatus includes the endless belt 1. The endless belt 1 is preferably formed by curing a resin composition containing a thiophene-based conductive polymer, or a material having a high Young's modulus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an endless belt and an image forming apparatus, and more particularly to an endless belt that contributes to forming a high quality image and an image forming apparatus capable of forming a high quality image.

  Various image forming apparatuses using an electrophotographic system are employed in printers such as laser printers and video printers, copiers, facsimiles, and multi-function machines thereof. An image forming apparatus using an electrophotographic system is, for example, a direct transfer system that directly transfers a developer image developed on an image carrier to a recording body according to the function of an endless belt, and a developer image that is once endless. There is an intermediate transfer method in which the image is transferred to a belt and transferred from an endless belt to a recording medium.

  More specifically, in the direct transfer method, an electrostatic latent image formed on an image carrier such as a photosensitive drum is developed with a developer supplied from a developer carrier provided in the developing unit, and is transferred to the transfer unit. By applying a voltage, the developed developer image is electrostatically attracted to an endless belt (also referred to as a transfer conveyance belt) and transferred to a recording medium conveyed between the image carrier and the transfer unit. In this method, the recording body onto which the developer image has been transferred is pressure-bonded or heat-pressed with a pressure roller and a fixing roller, and the transferred developer image is completely fixed as an image or text on the recording medium. The intermediate transfer method is, for example, an endless belt (also called an intermediate transfer belt) that develops an electrostatic latent image formed on an image carrier with a developer and abuts or presses the developed developer image on the image carrier. The developer image transferred to the endless belt is transferred to the recording medium (secondary transfer), and the recording medium onto which the developer image has been transferred is transferred by the pressure roller and the fixing roller. This is a method in which the transferred developer image is completely fixed as an image or text on the recording medium by pressure bonding or thermocompression bonding.

  As an endless belt attached to these image forming apparatuses, for example, Patent Document 1 describes an endless belt made of a thermoplastic resin. These endless belts are generally stretched between a plurality of rollers with a tension of, for example, about 0.007 to 0.025 MPa, and run on an endless track at a high speed by a driving roller or the like, and a transfer to which voltage is applied. A voltage is applied through means or the like. In addition, the temperature and humidity of the surrounding environment of the endless belt stretched around the roller may change, and sometimes the environment may be a severe environment of high temperature and high humidity. Therefore, in addition to tensile strength, Young's modulus, flexibility, bending strength, conductive properties, etc., the endless belt always receives a voltage applied from the transfer means during transfer of the developer image and maintains a predetermined potential. Properties such as conductive properties that can be achieved are particularly important.

  However, even an endless belt excellent in these characteristics is stretched on a roller and forms a good image for a while (for example, about 10 days), but the roller has a long period of time (for example, 30 days). If the image is stretched over a certain extent, for example, dot-like and / or streaky white spots due to non-transfer of the developer may occur in the formed image, and a good image may not be formed. It was.

JP 2001-022194 A

  An object of the present invention is to provide an endless belt that contributes to forming a high-quality image and an image forming apparatus capable of forming a high-quality image.

As means for solving the problems,
Claim 1 is an endless belt characterized in that a dent amount generated by a dent load test performed by applying a compression load of 2300 g to a sphere having a diameter of 0.7 mm is 10 μm or less,
Claim 2 is the endless belt according to claim 1, wherein the endless belt is formed by curing a resin composition containing a thiophene conductive polymer.
The endless belt according to claim 1, wherein the endless belt is formed by curing a high Young's modulus material.
Claim 4 is the endless belt according to any one of claims 1 to 3, wherein the endless belt has a Young's modulus of 3,000 MPa or more.
The stress relaxation rate when the endless belt is stretched by 2.5% in the circumferential direction is 13.5% or less, and the endless belt according to any one of claims 1 to 4 An endless belt,
6. The endless belt according to any one of claims 1 to 5, wherein the endless belt has a permanent set of 0.3% or less when stretched by 2.5% in the circumferential direction. Belt,
A seventh aspect is an image forming apparatus including the endless belt according to any one of the first to sixth aspects.

  The endless belt according to the present invention has a dent amount generated by a dent load test performed by applying a compression load of 2300 g to a sphere having a diameter of 0.7 mm and is 10 μm or less. Even if it is mounted, repeated running and stopping, and even if the surrounding environment of the stretched roller is changed, it is possible to maintain a predetermined size and shape, particularly high flatness of the surface. As a result, the endless belt according to the present invention can transfer and carry the developer as desired from an image carrier such as a photosensitive drum, and can transfer the developer to the recording member as desired. It is possible to prevent the occurrence of spot-like and / or streak-like white spots due to non-transfer of the developer. Therefore, according to the present invention, it is possible to provide an endless belt that contributes to forming a high-quality image and an image forming apparatus capable of forming a high-quality image.

  Hereinafter, an endless belt according to an embodiment of the present invention will be described with reference to the drawings. The endless belt 1 is formed in a ring shape as shown in FIG. 1 with a thiophene-based conductive polymer-containing resin composition described later or a high Young's modulus material described later. That is, the endless belt 1 is formed by annularly molding a thiophene-based conductive polymer-containing resin composition or a high Young's modulus material.

  The endless belt 1 has a dent amount of 10 μm or less generated by a dent load test performed by applying a compression load of 2300 g to a sphere having a diameter of 0.7 mm. When the dent amount in this dent load test exceeds 10 μm, the endless belt 1 is stretched between a plurality of rollers with a predetermined tension over a long period of time, and when the running and stopping are repeated, the endless belt 1 runs meandering When the surrounding environment of the stretched roller changes, the predetermined size and shape may not be maintained. As described above, when the endless belt 1 cannot maintain a predetermined size or the like, the surface of the endless belt 1, particularly the transfer surface carrying the developer, cannot be kept high, and as a result, The endless belt 1 that has lost its high flatness can transfer and carry the developer as desired from an image carrier such as a photosensitive drum, and can transfer the developer to the recording member as desired. Disappear. Therefore, in the image formed by the image forming apparatus equipped with the endless belt 1 that has lost such high flatness, dot-like and / or streaky white spots due to non-transfer of the developer occur, It becomes impossible to contribute to forming quality image quality. In the above case, the endless belt 1 can maintain a predetermined size and shape, and can greatly contribute to the formation of a high-quality image, so that the dent amount in the dent load test is 5 μm. It is preferable that it is below, and it is especially preferable that it is 2 micrometers or less. On the other hand, the lower limit of the dent amount in the dent load test is not particularly limited, but is preferably 1 μm, and is particularly preferably 1.5 μm because the lower limit value can be easily adjusted. When the dent amount in the dent load test is less than 1 μm, the stretchability of the endless belt 1 becomes low and becomes brittle. Therefore, when the endless belt 1 is mounted on the image forming apparatus and travels on an endless track at a high speed, the endless belt 1 breaks. Etc. may occur.

  The dent amount of the endless belt 1 in the dent load test can be obtained as follows. That is, one or a plurality of specimens of 50 mm × 60 mm are cut out from the endless belt 1, and the specimens cut out as desired are overlapped (not bonded or the like) to obtain a specimen having a thickness of 1 mm. Tensile tester equipped with a sphere having a diameter of 0.7 mm (for example, a ballpoint pen tip (ball diameter 0.7 mm, trade name “replacement core K-0.7 core”, manufactured by Zebra Corporation)) as a contact for making a dent. The test specimen is fixed to a test stand (trade name “Tensilon”, model “RTM-100”, manufactured by Orientec Co., Ltd.). Then, a compressive load of 2300 g is applied to the contactor perpendicularly (in the thickness direction of the specimen) with respect to the surface of the specimen (the specimen surface located in the uppermost layer when specimens are stacked), A contact is pressed vertically against the surface of the specimen for 5 seconds. Thereafter, the contactor is pulled away from the test body, and in this test body (specimen positioned in the uppermost layer when specimens are stacked), the amount of recesses formed by pressing the contactor is determined as the surface roughness. Measurement is performed using a meter (trade name “590A”, manufactured by Tokyo Seimitsu Co., Ltd.). This operation is performed at three points of the test body (three measurement points, the distance between the measurement points can be set to about 25 mm, for example), and the arithmetic average value of each measured amount of dents is measured on the endless belt 1. The amount of dents. In addition, the amount of recesses formed in the specimen is measured at a tracing speed of 0.3 and a cross-sectional curve P using a measurement probe having a tip radius of 2 μm.

  The amount of dents in the endless belt 1 is the type of resin contained in the thiophene-based conductive polymer-containing resin composition described later or the high Young's modulus material described later, the type of conductivity imparting agent, the content of the conductivity imparting agent, and / or Or it can adjust by changing the solvent residual amount of the endless belt 1, etc.

  The endless belt 1 preferably has a Young's modulus of 3000 MPa or more, more preferably 4000 MPa or more, and particularly preferably 4500 MPa or more. When the Young's modulus is within the above range, the endless belt 1 is very flexible, and even if it is stretched over a long period of time on a plurality of rollers and drive rollers in a state where a predetermined tension is applied, The endless belt 1 is less likely to be damaged and the deformation of the endless belt 1 with respect to stress during driving is reduced, so that the predetermined dimensions and shape of the endless belt 1 can be maintained at a high level. As a result, high quality image quality can be stably formed. Can contribute greatly to On the other hand, the upper limit of Young's modulus is not particularly limited, but is preferably 6000 MPa, more preferably 5500 MPa, and particularly preferably 5000 MPa. If the upper limit of the Young's modulus exceeds the above range, the endless belt 1 may become brittle and cracks may occur.

  The Young's modulus of the endless belt 1 can be obtained from the equation E = ΔS / Δa by measuring the force ΔS applied to the unit cross-sectional area and the elongation Δa in the unit length. Here, in the above expression, ΔS is expressed by the expression ΔS = F / (w × t) from the load F, the thickness t and the width w of the endless belt 1, and Δa is the reference length L of the endless belt 1. From the elongation ΔL of the endless belt 1 when a load is applied, Δa = ΔL / L. The Young's modulus of the endless belt 1 can also be measured using a tensile tester, for example, a trade name “MODEL-1605N” (manufactured by Aiko Engineering Co., Ltd.). The Young's modulus of the endless belt 1 is adjusted by the type of resin contained in the thiophene-based conductive polymer-containing resin composition or the high Young's modulus material, the content of the resin, and / or the solvent residual amount of the endless belt 1, etc. can do.

  The endless belt 1 preferably has a stress relaxation rate of 13.5% or less when stretched by 2.5% in the circumferential direction, more preferably 12% or less, and particularly preferably 11% or less. . When the stress relaxation rate is within the above range, even if the endless belt 1 is deformed, the endless belt 1 itself is easily returned to its original state due to the stretchability of the endless belt 1, and the predetermined size and shape of the endless belt 1 are maintained. As a result, good image quality can be stably obtained. On the other hand, the lower limit of the stress relaxation rate is not particularly limited, but is preferably 1%, more preferably 2%, and particularly preferably 3%. If the lower limit of the stress relaxation rate is less than the above range, the endless belt 1 is attached to the image forming apparatus and may be deformed when traveling on an endless track at a high speed.

The stress relaxation rate of the endless belt 1 can be obtained as follows. That is, a test piece cut out from the endless belt 1 having a length of 300 mm along the circumferential direction and an area of a cross section perpendicular to the circumferential direction of 0.4 mm ² (for example, when the thickness of the endless belt 1 is 0.1 mm). 3 specimens are cut out so that the width of the specimen is 4 mm. Each of these test pieces is set on a pair of workpieces facing each other at an interval of 200 mm in a tensile tester (trade name “Tensilon”, model “RTM-100”, manufactured by Orientec Co., Ltd.). At this time, the test piece is clamped by the workpieces up to 50 mm from both ends. In the longitudinal direction of the test piece set on the pair of workpieces (the circumferential direction of the endless belt 1, in other words, the direction in which the pair of workpieces are separated), the tensile distance is 5 mm and the tensile distance is 5 mm (that is, the distance between the workpieces is 205 mm). When the tensile distance becomes 2.5% with respect to the total length of 200 mm in the longitudinal direction of the test piece, the movement of the workpiece is stopped and this state is maintained for 30 seconds. The distance between the workpieces is restored to 200 mm. In this way, the tensile load applied to the test piece until the pair of workpieces are moved from the initial state to the state extended by 2.5% in the circumferential direction and returned to the initial state after 30 seconds have elapsed in this extended state. The elongation of the test piece is continuously measured. Among the measured tensile loads, the maximum tensile load and the tensile load after maintaining the 2.5% stretched state for 30 seconds (that is, immediately before the workpiece is moved to return to the initial state) are read, From these values, the tensile stress relaxation rate (%) of the test piece is calculated by the formula {1- (tensile load after holding for 30 seconds / maximum tensile load)} × 100. The tensile stress relaxation rate of each test piece is arithmetically averaged to obtain the tensile stress relaxation rate of the endless belt 1.

  The stress relaxation rate of the endless belt 1 changes the type of resin contained in the thiophene-based conductive polymer-containing resin composition or the high Young's modulus material, the content of this resin, and / or the residual solvent amount of the endless belt 1, etc. By doing so, it can be adjusted.

  The endless belt 1 preferably has a permanent set of 0.3% or less when stretched by 2.5% in the circumferential direction, more preferably 0.25% or less, and 0.15% or less. Is particularly preferred. When the permanent distortion is within the above range, the predetermined size and shape of the endless belt 1 can be maintained, and as a result, good image quality can be stably obtained. On the other hand, the lower limit of the permanent set is not particularly limited, but is preferably 0.01%, more preferably 0.05%, and particularly preferably 0.1%. When the lower limit of the permanent distortion is less than the above range, the endless belt 1 is attached to the image forming apparatus, and when traveling on an endless track at a high speed, it becomes difficult to follow the driven roller that stretches the endless belt 1. Here, the permanent distortion of the endless belt 1 refers to the amount of deformation with respect to the initial length of the endless belt 1 that remains on the endless belt 1 after the tensile load is applied to the endless belt 1 and the tensile load is removed. The ratio of the length of the endless belt 1 to which the endless belt 1 is stretched in the tensile direction with respect to the length of the endless belt 1 before the load is applied.

  The permanent strain of the endless belt 1 is increased by 2.5% in the circumferential direction from the initial state in the same manner as in the measurement of the stress relaxation rate, and when the extended state is restored to the initial state again after 30 seconds. Then, the elongation amount of the test piece to be measured (the length when the test piece is stretched and then returned to the initial state−the length of the cut specimen) is read, and the formula (elongation amount / 200) is calculated from this elongation amount. The permanent set (%) of the test piece is calculated by × 100. The permanent strain of each test piece is arithmetically averaged to obtain the permanent strain (%) of the endless belt 1.

  The permanent set of the endless belt 1 changes the type of resin contained in the thiophene-based conductive polymer-containing resin composition or the high Young's modulus material, the content of the resin, and / or the solvent residual amount of the endless belt 1, etc. Can be adjusted.

  The endless belt 1 is formed by curing a thiophene-based conductive polymer-containing resin composition or a high Young's modulus material. The high Young's modulus material forming the endless belt 1 may be a resin composition that can satisfy the dent amount in the test method. Examples of the resin composition include a p-phenylene skeleton, a biphenyl skeleton, and Examples thereof include a resin composition containing a resin having in its molecule at least one skeleton selected from naphthalene skeletons. As a resin having such a skeleton, for example, a polyimide resin (specifically, polyimide resin (PI), polyamideimide resin (PAI), polyetherimide resin (PEI), polyester having the skeleton in the molecule) Examples thereof include resin compositions containing resins such as imide resins (EI) and the like, and polyester resins (specifically, polybutylene terephthalate (PBT) and polyethylene terephthalate (PET)). Among the skeletons, it is preferable to have a biphenyl skeleton in the molecule from the viewpoint of excellent compatibility with other components contained in the resin composition.

  The resin having the skeleton in the molecule is a monomer that forms the resin and the amount of the monomer having the skeleton is 5 to 95 when the number of moles of all monomers constituting the resin is 100 mol%. The mol% is preferable from the viewpoint of increasing the Young's modulus of the resin, and particularly preferably 10 to 90 mol%.

  The monomer for forming the resin having the skeleton in the molecule is not particularly limited, and specific examples of the monomer for introducing the p-phenylene skeleton into the resin include p-phenylenediamine, p- Examples include xylylenediamine, 2,4-tolylenediamine, 2,6-tolylenediamine, and isocyanates corresponding to these amines. Examples of monomers for introducing a biphenyl skeleton into the resin include 3 3,3′-dimethylbiphenyl-4,4′-diamine, o-tolidine, benzidine, isocyanates corresponding to these amines, and the like, and 4,4′-diphenyldicarboxylic acid, 3,3 ′, 4,4 '-Biphenyltetracarboxylic acid and its anhydride, etc., and as a monomer for introducing a naphthalene skeleton into the resin Is, for example, naphthalene dicarboxylic acid, naphthalene diamine, and an isocyanate or the like corresponding to these.

  On the other hand, as monomers having no skeleton among the monomers forming the resin, for example, pyromellitic acid, diphenyl ether tetracarboxylic acid, diphenylsulfone tetracarboxylic acid, benzophenone tetracarboxylic acid, trimellitic acid and anhydrides thereof Examples of ditrimate esters such as glycol include ethylene glycol ditrimellitate, propylene glycol ditrimellitate, butylene glycol ditrimellitate, and diethylene glycol trimellitate. Among these, pyromellitic acid, trimellitic acid, and anhydrides thereof are preferable from the viewpoint of price, reactivity, and heat resistance.

  Examples of monomers that do not have the skeleton among the monomers forming the resin include, for example, 4,4′-diphenylmethanediamine, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3 , 4′-diaminodiphenyl ether, isophorone diamine, and one or a combination of two or more selected from these diisocyanates.

  Further, among the monomers forming the resin, monomers having no skeleton include terephthalic acid, isophthalic acid, 4,4′-biphenyl ether dicarboxylic acid, 4,4′-biphenylsulfone dicarboxylic acid, and 4,4′-benzophenone. Examples include aromatic dicarboxylic acids such as dicarboxylic acids, carboxylic acids, adipic acid, sebacic acid, maleic acid, fumaric acid, dimer acid, stilbene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, etc. Aliphatic dicarboxylic acids, and polyalcohols such as glycols.

  Moreover, the active terminal of the said polyimide-type resin can also be denatured and an amine or isocyanate etc. are mentioned as an active terminal modifier. As the amine or isocyanate, o-tolidine, benzidine, and these diisocyanates are preferable from the viewpoint of heat resistance, strength, and elastic modulus. In addition, the active terminal of the polyimide resin can be sealed, and examples of the terminal blocking agent include amines. Examples of the amine as the terminal blocking agent include ethylene diamine, propylene diamine, and hexamethylene diamine.

  The high Young's modulus material contains a conductivity imparting agent in addition to the resin. Examples of the conductivity-imparting agent include carbon black such as ketjen black and acetylene black, oxidation-treated carbon black added with a carboxy group, a hydroxy group, etc. by oxidation treatment (more preferably oxidation-treated carbon black having a pH of 6 or less), Examples thereof include metal powders such as titanium oxide, zinc oxide, nickel, copper, silver, and germanium, and conductive polymers such as polyaniline, polypyrrole, and polyacetylene.

  This high Young's modulus material may contain, in addition to the resin and the conductivity-imparting agent, a polyamine, a filler described later, and the like as desired.

  The thiophene-based conductive polymer-containing resin composition forming the endless belt 1 may be any resin composition that can satisfy the dent amount. For example, the thermoplastic resin not having the skeleton and the skeleton have the skeleton. And a resin composition containing a thiophene-based conductive polymer. Examples of the thermoplastic resin and thermosetting resin contained in the resin composition include polyamideimide resin (PAI) having no skeleton, polyimide resin (PI) having no skeleton, and polyamide having no skeleton. Resins (PA), polyethylene terephthalate (PET) having no skeleton, polybutylene terephthalate (PBT) having no skeleton, polyethylene naphthalate (PEN) not having the skeleton, cross-linked polyester resin, and the like. And polyester resins that are not used. Among these, polyamideimide resin, polyimide resin, and polyamide resin are preferable, and polyamideimide resin is more preferable. In particular, aromatic polyamideimide resin has mechanical properties such as strength, flexibility, dimensional stability, and heat resistance. It is preferable in terms of excellent balance. The monomers constituting these thermoplastic resins and thermosetting resins are not particularly limited to the monomers exemplified as the monomer having no skeleton in the high Young's modulus material, and can be exemplified.

  The resin composition contains a thiophene conductive polymer composed of a thiophene polymer and an electron acceptor. Examples of the thiophene polymer include polymers represented by the following general formula (I) and the following general formula (II).

  In general formula (I), n> 1, and A represents an alkylene group having 4 or less carbon atoms which may have a substituent.

  Examples of A in the general formula (I) include, for example, methylene group, ethylene group, 1,2-propylene group, 1,3-propylene group, 1,2-butylene group, 2,3-butylene group, 1 , 2-isobutylene group, 1,3-butylene group, 1,4-butylene group, phenyl-substituted ethylene group, 1,2-diphenyl-substituted ethylene group, and the like. Of these, A is preferably a methylene group, an ethylene group, or a 1,2-propylene group.

  N in the general formula (I) is preferably 1 or more and 300 or less, and is 3 to 100 from the viewpoint of uniform dispersibility in the thermoplastic resin not having the skeleton and the thermosetting resin not having the skeleton. More preferred.

In the general formula (II), n> 1, and R ¹ and R ² each independently have hydrogen, an alkyl group having 1 to 12 carbon atoms which may have a substituent, or a substituent. And an aryl group which may have a substituent, an acyl group which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, and an aryloxy group which may have a substituent.

Examples of the alkyl group represented by R ¹ and R ² in the general formula (II) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and an undecyl group. Group, dodecyl group and the like. Examples of the aryl group for R ¹ and R ² include a phenyl group, a tolyl group, a biphenyl group, a naphthyl group, an anthryl group, and a pyrenyl group. Examples of the acyl group for R ¹ and R ² include an acetyl group, a propionyl group, a benzoyl group, a toluoyl group, and a cyclohexylcarbonyl group. Examples of the alkoxy group for R ¹ and R ² include a methoxy group, an ethoxy group, and a butoxy group. Moreover, as an aryloxy group of R < ¹ > and R < ² >, a phenoxy group etc. are mentioned, for example. Among these, as R ¹ and R ² , a methyl group, a butyl group, a hexyl group, a nonyl group, a phenyl group, a biphenyl group, a methoxy group, an ethoxy group, a butoxy group, and a phenoxy group are preferable.

  N in the general formula (II) is preferably 1 or more and 300 or less, similarly to n in the general formula (I), and is suitable for thermoplastic resins not having the skeleton and thermosetting resins not having the skeleton. 3-100 are more preferable from the point of uniform dispersibility.

  The thiophene-based polymer is generally a black compound insoluble in a solvent. Among the polymers represented by the general formula (I) and the following general formula (II), the polymerization site selectivity at the time of polymerization, conductivity From the viewpoints of transparency, flexibility and the like, the polymer represented by the general formula (I) is preferable. Particularly suitable thiophene-based polymers include 2,3-ethylenedioxythiophene where A in the general formula (I) is an ethylene group.

  The thiophene polymer may be produced as appropriate, or a commercially available product may be used. For example, 2,3-ethylenedioxythiophene can be obtained as a trade name “BAYTRON M” (manufactured by Bayer).

The electron acceptor is doped into the thiophene polymer in order to improve the electrical conductivity of the thiophene polymer, and can be used without particular limitation as long as it oxidizes the thiophene polymer. For example, the electron acceptor includes at least one selected from halogen, metal halide, cyano compound, Lewis acid, proton acid, and organometallic compound. Examples of the halogen, metal halide, and Lewis acid include I ₂ , Br ₂ , SbF ₅ , AsF _{5 and the} like. Examples of the cyano compound include tetracyanoquinodimethane, tetracyanobenzene, tetracyanoethylene, and the like. Examples of the organometallic compound include tris (4-bromophenyl) ammonium hexachloroantimonate, bis (dithiobenzyl) nickel, tetra-n-butylammonium bis (1,3-dithiol-2-thione-4,5-dithiolate ) Nickel (III) complex and the like. Examples of the protic acid include inorganic acids such as HF, HCl, H ₂ SO ₄ , and H ₃ BO _3, organic compounds having a sulfonic acid group, and an amino acid group. Preferable examples include boric acid, p-toluenesulfonic acid and its compound, polystyrene sulfonic acid (PSS) and its compound. In particular, the polystyrene sulfonic acid (PSS) represented by the following formula (III), its compound, and its polymer form a strong complex with the thiophene compound in the oxidized state, so there is no change in electrical characteristics due to dedoping. Is particularly preferred.

  M and n in the formula (III) are each a number of 1 to 3000, and preferably 1 to 1500. The amount of the electron acceptor with respect to the thiophene polymer is not particularly limited, but in order to obtain suitable conductivity, it is 0.1 to 300 parts by mass with respect to 100 parts by mass of the thiophene polymer. Preferably, it is 30-200 mass parts.

  The thiophene-based conductive polymer composed of the thiophene-based polymer and the electron acceptor may be appropriately manufactured, or a commercially available product may be used. For example, a dope dispersion obtained by combining a thiophene polymer in which A is an ethylene group in the general formula (I) with polystyrene sulfonic acid (PSS) represented by the formula (III) and a compound thereof is, for example, a trade name “BAYTRON” P ”(manufactured by Bayer). Its structure is shown in Formula (IV).

  The resin composition contains substantially no filler other than the thiophene conductive polymer. When the resin composition contains the thiophene-based conductive polymer and does not substantially contain a filler, the dent amount of the endless belt can be easily adjusted within the above range. In this invention, a filler is a filler normally used for a resin composition and various electroconductivity imparting agents. Examples of the filler usually used in the resin composition forming the endless belt include silica, quartz powder, carbon black, talc, zeolite, glass fiber, carbon fiber, calcium carbonate, zinc carbonate, magnesium oxide, and the like. In addition, various conductivity imparting agents include carbon black such as ketjen black and acetylene black, metal powder such as titanium oxide, zinc oxide, nickel, copper, silver and germanium, and high conductivity such as polyaniline, polypyrrole and polyacetylene. Molecule and the like.

  The resin composition may contain celluloid, silicon rubber and the like in addition to the thermoplastic resin and thermosetting resin, and the thiophene conductive polymer.

  This thiophene-based conductive polymer-containing resin composition is difficult to be deformed when it is used as the endless belt 1 and has elasticity, so that it functions in the same manner as the high Young's modulus material, and Has the same effect as the rate material.

  As shown in FIG. 1, the endless belt 1 has a single layer structure, but may have a multilayer structure in which two or more layers are laminated. The thickness of the endless belt 1 is not particularly limited, but usually, for example, preferably 0.03 to 1 mm, more preferably 0.05 to 0.2 mm, and about 0.07 to 0.14 mm. Is particularly preferred. If the thickness of the endless belt 1 is less than 0.03 mm, the mechanical strength of the endless belt 1 may decrease. On the other hand, if the thickness exceeds 1 mm, the flexibility of the endless belt 1 decreases and durability increases. May be inferior. The thickness of the endless belt 1 can be measured by a contact film thickness meter or a non-contact film thickness meter, for example, an overcurrent film thickness meter (trade name “CTR-1500E”, manufactured by Sanko Electronics Co., Ltd.). ) Can be used. The width and inner diameter of the endless belt 1 are set to a desired width according to the use of the endless belt 1, that is, the position (component) disposed in the image forming apparatus, the interval between a plurality of stretched rollers, and the like. And it is arbitrarily set so that it may become an inner peripheral diameter. For example, the endless belt 1 has a width of 200 to 350 mm and an inner peripheral diameter of 200 to 2,500 mm.

  For the endless belt 1, the thiophene-based conductive polymer-containing resin composition or the high Young's modulus material (hereinafter sometimes simply referred to as a resin composition for forming an endless belt) is used in a known molding method, for example, It is formed into an annular shape by centrifugal molding, extrusion molding, injection molding, RIM molding or the like. Among these molding methods, centrifugal molding is preferable in that it can be applied regardless of the material and is excellent in thickness accuracy.

  When the endless belt 1 is molded by centrifugal molding, the endless belt forming resin composition for forming the endless belt 1 is preferably adjusted to have a viscosity at molding of 50,000 mPa · s or less. When the viscosity exceeds 50,000 mPa · s, it may be difficult to produce the endless belt 1 having a uniform thickness. The lower limit of the viscosity of the endless belt-forming resin composition is not particularly limited, but is preferably 10 mPa · s or more. When the viscosity of the resin composition for forming an endless belt is out of the above range, the viscosity of the resin composition for forming an endless belt can be adjusted within the above range by adjusting the amount of the solvent added. As a solvent, the solvent used for the polycondensation reaction which synthesize | combines the said aromatic polyamideimide resin is mentioned.

  According to centrifugal molding, a resin composition for forming an endless belt that expresses fluidity by containing a solvent is poured into a cylindrical mold, and the mold is rotated to rotate the mold on the inner peripheral surface of the mold by centrifugal force. The layer of the resin composition for forming is uniformly developed, and the solvent is dried and removed from the layer of the resin composition for forming the endless belt to produce an endless belt substrate. Various metal pipes can be used for the mold. As a suitable mold, the inner peripheral surface of the mold is mirror-polished, and the inner peripheral surface that becomes the mirror surface is subjected to a release treatment with a release agent such as a fluororesin or a silicone resin, and the formed endless belt base is formed. Examples thereof include a metal tube that can be easily removed from the inner peripheral surface.

  In the case where a polyamideimide resin is selected as the resin contained in the resin composition for forming an endless belt, in addition to the above-described centrifugal molding, a tricarboxylic acid anhydride and a diisocyanate compound, which are raw materials for the polyamideimide resin having the skeleton, are used. A solution of a polyamic acid partially polymerized with or a mixture of this solution and the thiophene-based conductive polymer is coated on the inner peripheral surface and outer peripheral surface of the mold by a dipping method, a centrifugal method, a coating method, etc. Alternatively, the polyamic acid solution is developed into a cylindrical shape by an appropriate method such as filling a casting mold, the developed layer is dried and formed into a belt shape, and the molded product is heat treated to obtain a polyamic acid. Known methods for converting the amide into an imide and recovering it from the mold (JP-A 61-95361, JP-A 64-22514, JP-A 3-180309, etc.) Accordingly, it is also possible to manufacture the endless belt 1.

  The solvent is removed from the layer of the resin composition for forming an endless belt developed on the inner peripheral surface of the mold to produce an endless belt base. Here, the solvent to be removed is a solvent contained in the layer of the endless belt-forming resin composition developed on the inner peripheral surface of the mold. For example, when adjusting the viscosity of the endless belt-forming resin composition In addition to the solvent used in the above, there may be mentioned a solvent used when the aromatic polyamideimide resin is synthesized. Examples of the treatment for removing the solvent from the layer of the resin composition for forming an endless belt developed on the inner peripheral surface of the mold include a heat treatment. To remove the solvent, the following primary solvent removal step and two It is preferable to perform the solvent removal process which consists of a next solvent removal process.

  In the primary solvent removal step, the mold is rotated while removing the solvent from the layer of the endless belt forming resin composition developed on the inner peripheral surface of the mold, and the endless belt forming resin composition layer is formed. A film-like molded body is obtained. In the primary solvent removal step, the solvent is removed by passing hot air of 40 to 150 ° C. through the mold for 5 to 60 minutes while rotating the mold. When the hot air temperature exceeds 150 ° C. and / or when the heating time exceeds 60 minutes, the molded film-like molded body may be oxidized.

  In the secondary solvent removing step, the film-like molded body molded in the primary solvent removing step is taken out from the centrifugal molding machine together with the mold, heated together with the mold to remove the solvent from the film-like molded body, To do. For example, when using a heater such as a hot air dryer or oven, the film-like molded body may be heated together with the mold at 200 to 300 ° C. for 1 to 3 hours, and when a superheated steam furnace is used. What is necessary is just to heat a film-like molded object for 0.5 to 3 hours with 200-260 degreeC superheated steam with a metal mold | die. In addition, if a deformation | transformation etc. of a film molded object can be prevented, a film molded object can be demolded from a metal mold | die, and a film molded object can also be heated on the said conditions.

  After producing the endless belt substrate from which the solvent has been removed in this manner, the endless belt substrate is taken out of the mold and allowed to cool. When the endless belt base is allowed to cool together with the mold, the endless belt base can be removed due to the difference in thermal expansion coefficient between the mold and the endless belt base. The endless belt base preferably has a solvent residual amount of 0.05 to 0.30% by mass. When the endless belt substrate has a solvent residual amount of 0.05 to 0.30 mass%, when the endless belt 1 is used, the endless belt 1 exhibits uniform conductive characteristics and receives an applied voltage from a transfer means or the like. However, a predetermined potential can be maintained. The solvent residual amount of the endless belt substrate is 0.05 in that it exhibits a more uniform conductive property and can maintain a predetermined potential even more stably even when applied voltage from a transfer means or the like. More preferably, it is -0.25 mass%, and it is especially preferable that it is 0.10-0.20 mass%. The amount of residual solvent in the endless belt substrate is determined by immersing a sample cut out from the endless belt substrate in ethanol for a predetermined time to extract the residual solvent in the endless belt substrate, and gas chromatography-mass spectrometry (GC-MS) Can be measured.

  In this way, the endless belt substrate having a desired solvent residual amount is removed from the mold, both end portions of the cylindrical endless belt substrate are removed, and the endless belt 1 is cut into a predetermined width, whereby the endless belt 1 is manufactured. The cutting machine that cuts the endless belt substrate may be an apparatus that can cut the endless belt substrate so that the cutting start point and the cutting end point of the endless belt substrate substantially coincide with each other.

  Next, an example of an image forming apparatus provided with the endless belt 1 according to the present invention (hereinafter sometimes referred to as an image forming apparatus according to the present invention) will be described with reference to FIG. The image forming apparatus 10 is an intermediate transfer type tandem color image forming apparatus.

  In this image forming apparatus 10, the endless belt 1 is stretched around two support rollers 42, a tension roller 43 and a backup roller 44 as an intermediate transfer belt as shown in FIG. 2. As shown in FIG. 2, the image forming apparatus 10 includes a backup roller 44 in the vicinity of the installation position of the backup roller 44, and a bias roller 45 that contacts or presses the backup roller 44 via the intermediate transfer belt 1. The secondary transfer unit 40 includes an electrode roller 46 that contacts or presses against the backup roller 44.

  As shown in FIG. 2, the image forming apparatus 10 includes image carriers 11 </ b> B, 11 </ b> C, 11 </ b> M, and 11 </ b> Y equipped in four types of developing units B, C, M, and Y arranged in series on the intermediate transfer belt 1. Therefore, the developing units B, C, M, and Y are arranged in series on the intermediate transfer belt 1.

  As shown in FIG. 2, the developing unit B is provided with a rotatable image carrier 11B on which an electrostatic latent image is formed, in contact with or in pressure contact with the image carrier 11B, or at a predetermined interval. The charging means 12B for charging the image carrier 11B, the exposure means 13B provided above the image carrier 11B and forming an electrostatic latent image on the image carrier 11B, and the image carrier 11B are in contact with or pressed against each other. Or developing means 20B for supplying the developer 22B with a constant layer thickness to the image carrier 11B and developing the electrostatic latent image, and an intermediate transfer belt below the image carrier 11B. 1, a transfer unit 14B that is provided so as to be in contact with or pressed through 1 and that is primarily transferred from the image carrier 11B to the intermediate transfer belt 1 and transferred to the intermediate transfer belt 1 Not remaining on the image carrier 11B And a cleaning unit 15B for removing the developer 22B, etc. was. As the image carrier 11B, the charging unit 12B, the exposure unit 13B, the transfer unit 14B, and the cleaning unit 15B, conventionally known ones can be appropriately selected and used.

  In addition, as shown in FIG. 2, the developing means 20B is provided in contact with or pressure contact with the image carrier 11B or at a predetermined interval, and a developer 22B is applied to the image carrier 11B with a certain layer thickness. , A rotatable developer carrying member 23B, and a housing 21B for housing the developer to be supplied to the developer carrying member 23B. As the developer carrier 23B, a conventionally known one can be appropriately selected and used, and the developer 22B can be used without particular limitation as long as it is a developer that can be charged by friction. Unit B contains a black developer. The developing means 20B may include a developer regulating member that regulates the layer thickness of the developer 22B by contacting or pressure-contacting the developer carrier 23B and charging the developer 22B by frictional charging.

  As shown in FIG. 2, the developing units C, M, and Y are configured similarly to the developing unit B. The developing units C, M, and Y accommodate a cyan developer 22C, a magenta developer 22M, and a yellow developer 22Y in housings 21C, 21M, and 21Y, respectively.

  As shown in FIG. 2, a fixing unit 30 that fixes various developers (electrostatic latent images) secondarily transferred to the recording body 16 is disposed downstream in the conveyance direction of the recording body 16 in the image forming apparatus 10. ing. As the fixing device 30, a fixing device including an endless belt 35 as a fixing belt is employed. As shown in FIG. 2, the fixing device 30 includes a fixing roller 31 and a fixing belt support roller 33 disposed in the vicinity of the fixing roller 31 in a housing 34 having an opening through which the recording medium 16 passes. A fixing belt 35 wound around the fixing roller 31 and the fixing belt support roller 33, and a pressure roller 32 disposed opposite to the fixing roller 31, and the fixing roller 31 and the pressure roller via the fixing belt 35. 32 is a pressure heat fixing device that is rotatably supported so as to abut or press against each other. The fixing belt support roller 33 may be a roller that is normally used in an image forming apparatus. For example, an elastic roller or the like is used. The fixing roller 31, the fixing belt support roller 33, and the pressure roller 32 each have a built-in heating body (not shown). The pressure roller 32 causes the endless belt 35 to be moved by a biasing means (not shown) such as a spring. Via the fixing roller 31. As the fixing unit 30, a heat roller fixing device including a fixing roller capable of generating heat, a heat fixing device such as an oven fixing device, a pressure fixing device including a pressurizing fixing roller, or the like may be employed.

  The image forming apparatus 10 is provided with a cassette (not shown) in which the recording bodies 16 are stacked and accommodated. The recording bodies in the cassette are fed one by one by a paper feed roller or the like and conveyed to the secondary transfer unit 40. The

  The image forming apparatus 10 forms an image as follows. First, the image carrier 11B of the developing unit B rotates clockwise, is uniformly charged by the charging unit 12B, and an image is exposed by the exposure unit 13B, so that an electrostatic latent image is formed on the surface of the image carrier 11B. Is done. Next, the black developer 22B is supplied to the image carrier 11B from the developer carrier 23B in the developing unit 20B, and the electrostatic latent image formed on the image carrier 11B is developed with the black developer 22B, and the developer image is developed. Is visualized as Next, the developer image visualized by the transfer unit 14B or the like on the intermediate transfer belt 1 that rotates counterclockwise (in the direction of the arrow) between the image carrier 11B and the transfer unit 14B at the same speed as the image carrier 11B. Is transferred (primary transfer). In this way, the developer image is visualized as a black image on the intermediate transfer belt 1.

  Next, in the same manner as the developing unit B, a cyan image, a magenta image, and a yellow image are superimposed on the black image developed on the intermediate transfer belt 1 by the developing units C, M, and Y, respectively. A color image is visualized on top. At this time, the bias roller 45 is not in contact with or pressed against the backup roller 44.

  The color image transferred onto the intermediate transfer belt 1 reaches the secondary transfer unit 40 by the rotation of the intermediate transfer belt 1, while the recording medium 16 has a predetermined interval between the intermediate transfer belt 1 and the bias roller 45. It is conveyed at the timing. At this time, the bias roller 45 is disposed so as to contact and press against the backup roller 44. Then, the color image visualized on the intermediate transfer belt 1 is transferred onto the recording medium 16 conveyed to the secondary transfer unit by pressure contact conveyance and bias application by the bias roller 45 and the backup roller 44. In this way, the color image is secondarily transferred to the recording medium 16. Next, the recording body 16 in which the color image is visualized is conveyed to the fixing unit 30 by the conveying unit, and passes through a contact portion or a pressure contact portion between the fixing roller 31 and the pressure roller 32 via the endless belt 1. Occasionally heated and / or pressurized to fix the secondary transferred color image as a permanent image. In this way, a color image is formed on the recording medium 16.

  Although the case where a color image is formed using the image forming apparatus 10 has been described, in the case of forming a monochrome image, the developer image primarily transferred to the intermediate transfer belt 1 is immediately transferred to the recording medium 16 by secondary transfer. Then, it may be conveyed to the fixing means 30.

  Another example of an image forming apparatus provided with the endless belt 1 according to the present invention (hereinafter sometimes referred to as an image forming apparatus according to the present invention) will be described with reference to FIG. The image forming apparatus 50 is an intermediate transfer type multi-pass color image forming apparatus.

  In this image forming apparatus 50, the endless belt 1 is stretched around two support rollers 42, a tension roller 43, and a backup roller 44 as an intermediate transfer belt as shown in FIG. As shown in FIG. 3, the image forming apparatus 50 includes a backup roller 44 in the vicinity of the installation position of the backup roller 44, and a bias roller 45 that contacts or presses the backup roller 44 via the intermediate transfer belt 1. The secondary transfer unit 40 includes an electrode roller 46 that contacts or presses against the backup roller 44.

  As shown in FIG. 3, the image forming apparatus 50 includes a developing unit 20 including four types of developing units B, C, M, and Y. The developing units B, C, M, and Y built in the developing unit 20 include a charging unit, an exposure unit, and the like, and store a black developer, a cyan developer, a magenta developer, and a yellow developer, respectively. As shown in FIG. 3, the developing unit 20 rotates counterclockwise, for example, and exposes an electrostatic latent image to the image carrier 11 described later with a developer. As the developing means 20 and the developing unit, conventionally known ones can be appropriately selected and used. The developing unit 20 may include a developer and a developer carrier, and a charging unit, an exposure unit, and the like may be disposed outside the developing unit 20 and in the vicinity of the image carrier 11.

  As shown in FIG. 3, a fixing unit 30 for fixing various developers (electrostatic latent images) secondarily transferred to the recording body 16 is disposed downstream in the conveyance direction of the recording body 16 in the image forming apparatus 50. ing. The fixing device 30 is configured in the same manner as the fixing device 30 of the image forming apparatus 10.

  The image forming apparatus 50 is provided with a cassette (not shown) in which the recording bodies 16 are stacked and accommodated, and the recording bodies in the cassette are fed one by one by a paper feed roller or the like and conveyed to the secondary transfer unit 40. The

  The image forming apparatus 50 forms an image as follows. First, the developing unit 20 rotates counterclockwise, and the developing unit B accommodated in the developing unit 20 is disposed on the image carrier 11 side. Next, an electrostatic latent image is formed on the surface of the image carrier 11 by the developing unit B, the electrostatic latent image is developed, and a developer image is visualized on the surface of the image carrier 11. Next, the image carrier 11 rotates clockwise, and on the intermediate transfer belt 1 that rotates counterclockwise (in the direction of the arrow) between the image carrier 11 and the transfer means 14 at the same speed as the image carrier 11. The visualized developer image is transferred (primary transfer). In this way, the developer image is visualized as a black image on the intermediate transfer belt 1. Next, the developing unit 20 rotates, and in the same manner as the developing unit B, a cyan image, a magenta image, and a yellow image are respectively formed on the black image developed on the intermediate transfer belt 1 by the developing units C, M, and Y. The color image is visualized on the intermediate transfer belt 1 by being superimposed. At this time, the bias roller 45 is not in contact with or pressed against the backup roller 44.

  The color image transferred onto the intermediate transfer belt 1 reaches the secondary transfer unit 40 by the rotation of the intermediate transfer belt 1, while the recording medium 16 has a predetermined interval between the intermediate transfer belt 1 and the bias roller 45. It is conveyed at the timing. At this time, the bias roller 45 is disposed so as to contact and press against the backup roller 44. The color image visualized on the intermediate transfer belt 1 is transferred onto the recording medium 16 conveyed to the secondary transfer unit 40 by pressure contact conveyance and bias application by the bias roller 45 and the backup roller 44. . In this way, the color image is secondarily transferred to the recording medium 16. Next, the recording body 16 in which the color image is visualized is transported to the fixing means 30 by the transporting means, and the color image transferred to the recording body 16 is fixed as a permanent image. In this way, a color image is formed on the recording medium 16.

  Although the case where a color image is formed using the image forming apparatus 50 has been described, in the case of forming a monochrome image, the developer image primarily transferred to the intermediate transfer belt 1 is immediately transferred to the recording medium 16 as a secondary transfer. Then, it may be conveyed to the fixing means 30.

  According to these image forming apparatuses 10 and 50, since the endless belt 1 is used as the intermediate transfer belt 1, even if the intermediate transfer belt 1 is stretched around a roller with a predetermined tension over a long period of time, a photosensitive drum or the like. The developer can be transferred and carried from the image carrier 11 in a desired manner, and the developer can be transferred to the recording member 16 as desired. It is possible to prevent the occurrence of streaky white spots. Therefore, according to these image forming apparatuses 10 and 50, a high-quality image can be formed.

  The image forming apparatuses 10 and 50 are electrophotographic image forming apparatuses. In the present invention, the image forming apparatuses 10 and 50 are not limited to the electrophotographic system. For example, electrostatic image forming is performed. It may be a device. The image forming apparatuses 10 and 50 are image forming apparatuses such as copying machines, facsimile machines, and printers.

Example 1
In a reaction vessel, N-methyl-2-pyrrolidone and pyromellitic acid 0.1 mol, 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride 0.2 mol, 3,3 ′, 4,4 ′ -Add 0.3 mol of benzophenone tetracarboxylic acid anhydride, 0.5 mol of trimellitic acid anhydride, 1 mol of o-tolidine diisocyanate, increase the temperature from room temperature to 150 ° C over 30 minutes with stirring, and maintain the same temperature for 5 hours Thus, an aromatic polyamideimide solution having a reactant concentration (substantially fully ring-closed polyamideimide resin) of 20% by mass was obtained (the amount of the monomer having the skeleton in the aromatic polyamideimide was 12%). N-methyl-2-pyrrolidone was further added to this solution to prepare a polyamideimide solution having a reactant concentration of 15% by mass. To the obtained polyamideimide solution, oxidation-treated carbon black (trade name “Printex 150T”, manufactured by Degussa, pH 4.0, volatile content 10.0%) is added to a total of 100 mass of polyamideimide resin and oxidation-treated carbon black. The resin composition, which is a material having a high Young's modulus, was prepared by mixing and dispersing in a pot mill for 24 hours. The mold used for molding has an inner diameter of 226 mm, an outer diameter of 246 mm, and a length of 400 mm, and the inner surface of the mold is mirror-polished by polishing. Next, ring-shaped lids (inner diameter: 170 mm, outer diameter: 250 mm) are fitted into the openings at both ends of the mold, the mold is closed, and the resin composition is rotated at a speed of 1,000 rpm. 190 g was injected around the circumference. Next, the mold was rotated at the same speed for 30 minutes to uniformly develop the resin composition layer on the inner peripheral surface of the mold. Next, while rotating the mold at the same speed, the temperature around the mold was maintained at 80 ° C. with a hot air dryer, and this state was maintained for 30 minutes to form a film-shaped molded body. Thereafter, the rotation of the mold was stopped, the film-shaped molded body was taken out from the centrifugal molding machine together with the mold, subjected to superheated steam treatment in a superheated steam furnace adjusted to 250 ° C. for 2 hours, allowed to cool at room temperature, and endless. Belt 1 was obtained. When the endless belt 1 is cooled together with the mold, the endless belt 1 is peeled off due to the difference in thermal expansion coefficient between the mold and the endless belt 1. Both end portions of the endless belt 1 were cut and cut into a size having a circumference of about 226 mm, a width of 240 mm, and a thickness of 100 μm to produce an endless belt 1A.

(Example 2)
Dissolve 206 g of sodium styrenesulfonate in 1000 mL of ion-exchanged water and add dropwise 20 minutes of 1.14 g of ammonium persulfate oxidizer solution previously dissolved in 10 mL of ion-exchanged water while stirring at 80 ° C. Stir for 12 hours. To the obtained sodium styrenesulfonate-containing solution, 1000 mL of sulfuric acid diluted to 10% by mass was added, and about 1000 mL of ion-exchanged water of the polystyrenesulfonate-containing solution was removed using an ultrafiltration method, and 2000 mL of ions were added to the remaining liquid. Exchange water was added, and about 2000 mL of ion exchange water was removed using an ultrafiltration method. The above ultrafiltration operation was repeated three times. Further, about 2000 mL of ion-exchanged water was added to the obtained filtrate, and about 2000 mL of ion-exchanged water was removed using an ultrafiltration method. This ultrafiltration operation was repeated three times. Water in the obtained solution (filtrate) was removed under reduced pressure to obtain colorless solid polystyrene sulfonic acid.

  36.7 g of the polystyrene sulfonic acid thus obtained and a solution of 14.2 g of 3,4-ethylenedioxythiophene dissolved in 2000 mL of ion-exchanged water were mixed at 20 ° C. While maintaining the obtained mixed solution at 20 ° C., with stirring, 29.64 g of ammonium persulfate and 8.0 g of ferric sulfate oxidation catalyst solution dissolved in 200 mL of ion-exchanged water were slowly added. Stir for hours. 2000 mL of ion-exchanged water was added to the obtained reaction solution, and about 2000 mL of ion-exchanged water was removed using an ultrafiltration method. This operation was repeated three times. Then, 200 mL of sulfuric acid diluted to 10% by mass and 2000 mL of ion-exchanged water are added to the obtained solution (filtrate), and about 2000 mL of ion-exchanged water is removed using an ultrafiltration method. 2000 mL of ion-exchanged water was added, and about 2000 mL of ion-exchanged water was removed using an ultrafiltration method. This operation was repeated three times. 2000 mL of ion-exchanged water was added to the remainder thus obtained, and about 2000 mL of ion-exchanged water was removed using an ultrafiltration method. This operation was repeated 5 times to obtain an aqueous solution of poly (3,4-ethylenedioxythiophene) (PSS-PEDOT) doped with about 1.5% by mass of blue polystyrene sulfonic acid. N-methyl-2-pyrrolidone was added to the 1.5% by mass solution thus obtained to obtain a solution having a poly (3,4-ethylenedioxythiophene) concentration of about 0.4% by mass. .

  0.1 mol of pyromellitic acid, 0.2 mol of 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride, 0.3 mol of 3,3 ′, 4,4′-benzophenonetetracarboxylic anhydride, trimellit Instead of 0.5 mol of acid anhydride and 1 mol of o-tolidine diisocyanate, trimellitic acid anhydride, equivalent diphenylmethane-4,4′-diisocyanate, and reaction raw materials (trimellitic acid anhydride and diphenylmethane-4,4 A polyamideimide solution was prepared in the same manner as in Example 1 except that 2 mol% of potassium fluoride (catalyst) was used with respect to the total number of moles of '-diisocyanate). In the obtained polyamideimide solution, instead of oxidation-treated carbon black (trade name “Printex 150T”, manufactured by Degussa, pH 4.0, volatile content 10.0%), about 0.4% by mass of the PSS-PEDOT The endless belt 1 was formed in the same manner as in Example 1 except that the solution was added at a ratio of 0.9% by mass with respect to 100% by mass in total of the polyamideimide resin and the PSS-PEDOT approximately 0.4% by mass solution. Manufactured. Both end portions of the endless belt 1 were cut and cut into a size having a circumference of about 226 mm, a width of 240 mm, and a thickness of 100 μm to produce an endless belt 1B.

(Comparative Example 1)

  Pyromellitic acid 0.1 mol, 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride 0.2 mol, 3,3 ′, 4,4′-benzophenone tetracarboxylic anhydride 0.3 mol, trimellitic acid Instead of 0.5 mol of anhydride, 1 mol of o-tolidine diisocyanate, trimellitic anhydride, equivalent diphenylmethane-4,4′-diisocyanate, and reaction raw materials (trimellitic anhydride and diphenylmethane-4,4 ′ -A polyamideimide solution was prepared in the same manner as in Example 1 except that 2 mol% of potassium fluoride (catalyst) was used with respect to the total number of moles of diisocyanate). Instead of the oxidized carbon black (trade name “Printex 150T”, manufactured by Degussa, pH 4.0, volatile content 10.0%), the resulting polyamideimide solution was mixed with basic carbon black (trade name “Toka Black #”). 7550F "(pH 7.5, volatile matter 1.5%, manufactured by Tokai Carbon Co., Ltd.)) was added at a ratio of 14% by mass to 100% by mass of the total of polyamideimide resin and basic carbon black, In the same manner as in Example 1, an endless belt 1 was obtained. Both end portions of the endless belt 1 were cut and cut into a size having a circumference of about 226 mm, a width of 240 mm, and a thickness of 100 μm to produce an endless belt 1C.

  The dent amount, Young's modulus, stress relaxation rate, and permanent strain of the thus produced endless belts 1A to 1C were measured by the above methods. The results are shown in Table 1.

  Next, the obtained endless belts 1A to 1C were subjected to an idling test under the following conditions, and the surface state of each endless belt after the test was observed. As a result, the endless belts 1 </ b> A and 1 </ b> B could not confirm the uneven portion and the surface thereof was smooth, but the endless belt 1 </ b> C could confirm the uneven portion on the surface and the surface state was not good.

<Idling test conditions>
Distance between two endless belt tension rollers: 225 mm
Travel speed of endless belt: 180mm / S
Endless belt tension: 0.02 MPa
Travel time: 30 days

  Further, the endless belts 1A to 1C are stretched around a roller with a tension of 0.02 MPa as an intermediate transfer belt in the image forming apparatus (trade name “MicroLine 9055c”, manufactured by Oki Data Co., Ltd.) shown in FIG. Later, when a solid print image was printed, in the image forming apparatus in which the endless belts 1A and 1B were stretched, the dot-like and / or streaky white spots were not generated in the formed image. Thus, in the image forming apparatus in which the endless belt 1C is stretched, dot-like and / or streak-like white spots are generated in the formed image.

FIG. 1 is a schematic perspective view showing an endless belt according to an embodiment of the present invention. FIG. 2 is a schematic view of a tandem color image forming apparatus which is an example of the present invention. FIG. 3 is a schematic view of a multi-pass color image forming apparatus which is an example of the present invention.

Explanation of symbols

1 Endless belt (intermediate transfer belt)
35 Endless belt (fixing belt)
10, 50 Image forming apparatus 11, 11B, 11C, 11M, 11Y Image carrier 12B, 12C, 12M, 12Y Charging means 13B, 13C, 13M, 13Y Exposure means 14, 14B, 14C, 14M, 14Y Transfer means 15B, 15C , 15M, 15Y Cleaning means 16 Recorder 20, 20B, 20C, 20M, 20Y Developing means 21B, 21C, 21M, 21Y, 34 Housing 22B, 22C, 22M, 22Y Developer 23B, 23C, 23M, 23Y Developer carrying Body 30 Fixing device 31 Fixing roller 32 Pressure roller 33 Fixing belt support roller 40 Secondary transfer portion 42 Support roller 43 Tension roller 44 Backup roller 45 Bias roller B, C, M, Y Development unit

Claims (7)

  An endless belt, wherein a dent amount generated by a dent load test performed by applying a compression load of 2300 g to a sphere having a diameter of 0.7 mm is 10 μm or less.   The endless belt according to claim 1, wherein the endless belt is formed by curing a thiophene-based conductive polymer-containing resin composition.   The endless belt according to claim 1, wherein the endless belt is formed by curing a high Young's modulus material.   The endless belt according to any one of claims 1 to 3, wherein the endless belt has a Young's modulus of 3,000 MPa or more.   The endless belt according to any one of claims 1 to 4, wherein the endless belt has a stress relaxation rate of not more than 13.5% when stretched in the circumferential direction by 2.5%.   The endless belt according to any one of claims 1 to 5, wherein the endless belt has a permanent set of 0.3% or less when stretched in the circumferential direction by 2.5%.   An image forming apparatus comprising the endless belt according to claim 1.

Images