JP2002137308A - Method for manufacturing polyimide belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyimide belt used for an electrophotographic apparatus such as a laser beam printer or a facsimile and a method for manufacturing the same. SOLUTION: The method for manufacturing the polyimide belt comprises the steps of immersing a cylindrical fiber with a solution containing a polyamic acid as a main component, thereafter drying and imiding the fiber, and finally obtaining the polyimide belt. The polyimide belt improving a mechanical strength can be simply manufactured at a low cost by using this method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyimide belt made of polyimide or a polyimide resin film.

[0002]

2. Description of the Related Art Polyimide resins have excellent heat resistance, dimensional stability, mechanical strength, and chemical stability, and are used in various applications such as flexible printed circuit boards and heat-resistant wire insulation materials. In addition, the belt-shaped molded product can be used in an electrophotographic apparatus such as a copying machine or a laser beam printer, an inkjet printer or a bubble jet (registered trademark).
Attention has been focused on its use as a printer component. For example, among belt-shaped molded products used in electrophotographic devices, high pressure is applied to belts for paper conveyance and toner transfer, and high temperature and pressure are applied to belts for toner fixing and the like. Can be Further, a high temperature is applied to the paper transport belt after the fixing step or the drying step. For this reason, since belts used in these apparatuses are required to have heat resistance and high mechanical properties, a polyimide resin is most preferable as the material of the belt. However, the characteristics required for this polyimide belt are extremely high. If the thickness of the polyimide belt varies, uniform transfer and fixing of the toner cannot be performed. Therefore, it is necessary to reduce the thickness variation as much as possible.
In addition, the variation in the inner diameter in the length direction of the belt causes the belt to meander when the belt is rotated for a long time. Therefore, it is better that the variation in the inner diameter is as small as possible. However, in recent years, electrophotographic devices tend to be smaller and less expensive. For this reason, it is essential that the polyimide belt used in these devices be provided at low cost. The conventional polyimide belt is very expensive because its manufacturing process is very complicated and the metal jig for forming it is extremely expensive. Conventional polyimide belts have been manufactured by the following method. For example, a solution prepared by dispersing or dissolving a polyamic acid in a solvent is applied to the outer surface of a surface-treated cylindrical or cylindrical mold, or is applied to the inner surface of a cylindrical mold to adjust the thickness. Then, the solvent is evaporated by heating, or the polyimide belt is manufactured by further heating.

[0003]

However, the following problems have been pointed out in such a conventional method. First, in this method, it is very difficult to remove the polyimide belt from the forming tube, and during the above-mentioned operation, it is inevitable that the yield is reduced due to breakage of the polyimide belt.
Furthermore, in this method, it is very difficult to uniformly control the thickness of the belt, that is, the thickness of the polyamic acid solution to be applied, and in order to achieve this, a jig with a very high degree of clearance adjustment has been used. I had to prepare. These jigs have a large number of sliding parts, have a short life, and are extremely expensive, which generally contributes to an increase in cost. In addition, as another method of producing a belt-shaped resin, there are an extrusion molding method, an injection method, and a method of injecting a liquid resin into a mold, but these are basically methods for thermoplastic resin, and are non-thermal methods. It is not suitable for molding polyamic acid of polyimide as a thermoplastic resin or thermosetting resin as a precursor of polyimide. Further, it is difficult to form a thin material having a thickness of several tens of μm by these methods, and there is a limit in dimensional accuracy. Moreover, these methods have a fatal defect that the apparatus and jig become extremely large and expensive.

[0004] Second, there is a problem of reduction in toughness. When using a polyimide belt for toner transfer, it is essential to greatly reduce the resistance value of the resin. Further, when used for fixing a toner, it is necessary to have high thermal conductivity. In order to satisfy these requirements, a method of incorporating an inorganic powder in a resin according to desired properties is generally used. However, when an inorganic powder is introduced into the resin, the resin toughness is significantly reduced. When a polyimide belt having low resin toughness is incorporated in an apparatus, a period until breakage such as breakage or cracking occurs in the resin, that is, a component life is shortened. As a result, it is very problematic that belt replacement costs are incurred, which leads to an increase in the cost of the apparatus as a whole. Conventionally, in order to improve the toughness of the belt resin, a method of increasing the thickness of the polyimide belt has been generally used. However, this method has problems such as the need to increase the heat capacity of the heater at the time of thermal fixing and the increase in resin raw material cost. This is one of the hindering factors. Further, the surface of the molded article is treated with a coating having an ability to improve toughness. However, this method also has a problem in that the heat capacity of the heater increases, the coating material cost and the coating processing cost increase, and the cost of the entire apparatus increases. Also, Japanese Patent Application Laid-Open No. 5-34
As disclosed in Japanese Patent No. 5369 and Japanese Patent Application Laid-Open No. 10-198179, means for providing a reinforcing tape at the end of a belt for the purpose of preventing damage has been proposed. However, this method is unsuitable in that the process of attaching the tape is very complicated and difficult, and the cost required for this process is increased.

The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have come to conceive a method of manufacturing a polyimide belt which is industrially inexpensive and has high toughness.

[0006]

The present invention can solve the above problems by the following method. 1) A method for producing a polyimide belt, comprising impregnating a polyimide precursor solution with a fiber woven in a cylindrical shape for preparing a polyimide belt basic structure, followed by drying and imidization. 2) 5 to 60 parts by weight of inorganic powder is contained in 100 parts by weight of the resin solid component in the polyimide precursor solution.
The method for producing a polyimide belt according to the above. 3) The method for producing a polyimide belt according to 1) or 2), wherein the thickness of the belt is controlled by polishing. 4) The method for producing a polyimide belt according to 1) to 3), wherein the fiber substrate is at least one of glass fiber, carbon fiber, Kevlar fiber, ceramic fiber, metal fiber, and aramid fiber. 5) The method for producing a polyimide belt according to 1) to 4), wherein the weave of the cylindrical fiber base material is any of plain weave, satin weave, and twill weave.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In order to achieve the above object, a method for producing a polyimide belt according to the present invention comprises impregnating a polyimide precursor solution with a fiber woven in a cylindrical shape for preparing a polyimide belt basic structure, and thereafter, It is characterized by performing drying and imidation. That is, the present invention relates to a method for producing a polyimide belt used as an intermediate transfer or a fixing belt in electrophotographic equipment such as a laser beam printer and a facsimile. In the method for producing a polyimide belt according to the present invention, the polyamic acid is obtained by, for example, polymerizing an aromatic tetracarboxylic acid component and a diamine component in an organic polar solvent. The aromatic tetracarboxylic acid component is not particularly limited, and examples thereof include butanetetracarboxylic dianhydride, 1,2,3,4
-Cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5 -Tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynorbonane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 5- (2,5- Dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,
Aliphatic or alicyclic tetracarboxylic dianhydrides such as 2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride; pyromellitic dianhydride; 3,3 ',
4,4′-benzophenonetetracarboxylic dianhydride,
3,3 ', 4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride 3,3 ′, 4,4′-biphenylethertetracarboxylic dianhydride, 3,3 ′, 4,4 ′
-Dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4 '-Bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,
4′-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride,
3,3 ′, 4,4′-perfluoroisopropylidene diphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenyl phosphine oxide dianhydride , P-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-
Aromatics such as bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'-diphenylmethane dianhydride Tetracarboxylic dianhydride; 1,3,3a, 4,5,9b-hexahydro-
2,5-dioxo-3-furanyl) -naphtho [1,2-
c] furan-1,3-dione, 1,3,3a, 4,5
9b-Hexahydro-5-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2
-C] furan-1,3-dione, 1,3,3a, 4,
Aliphatic tetra having an aromatic ring such as 5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione Carboxylic dianhydrides and the like can be mentioned. These tetracarboxylic dianhydrides can be used alone or in combination of two or more. The diamine used next is not particularly limited as long as it is a diamine. For example, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane,
4,4′-diaminophenylethane, 4,4′-diaminophenyl ether, 4,4′-didiaminophenyl sulfide, 4,4′-didiaminophenyl sulfone,
1,5-diaminonaphthalene, 3,3-dimethyl-4,
4'-diaminobiphenyl, 5-amino-1- (4'-
Aminophenyl) -1,3,3-trimethylindane,
6-amino-1- (4'-aminophenyl) -1,3,3
3-trimethylindane, 4,4'-diaminobenzanilide, 3,5-diamino-3'-trifluoromethylbenzanilide, 3,5-diamino-4'-trifluoromethylbenzanilide, 3,4'-diamino Diphenyl ether, 2,7-diaminofluorene, 2,2-bis (4-aminophenyl) hexafluoropropane,
4,4′-methylene-bis (2-chloroaniline),
2,2 ', 5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy- 4,4′-diaminobiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2- Bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 1,4
-Bis (4-aminophenoxy) benzene, 4,4'-
Bis (4-aminophenoxy) -biphenyl, 1,3 ′
-Bis (4-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) fluorene, 4,4 '-(p
-Phenyleneisopropylidene) bisaniline, 4,
4 '-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-bis [4- (4 An aromatic diamine such as -amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl; two amino groups bonded to an aromatic ring such as diaminotetraphenylthiophene and a hetero atom other than a nitrogen atom of the amino group; Aromatic diamine having: 1,1-methaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,
4-diaminocyclohexane, isophoronediamine,
Tetrahydrodicyclopentadiene cyclopentadienylide diamine, hexahydro-4,7-meth Noin mite range diamine, tricyclo [6,2,1,0 ^2.7] - undecylenate range methyl diamine, 4,4'-methylenebis such (cyclohexylamine) Examples thereof include aliphatic diamines and alicyclic diamines. These diamine compounds can be used alone or in combination of two or more. As the diamine, it is preferable to use an aromatic diamine, but it is not particularly limited. Here, as the organic polar solvent used in the reaction for producing the polyamic acid,
For example, sulfoxide solvents such as dimethylsulfoxide and diethylsulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, and acetamide solvents such as N, N-dimethylacetamide and N, N-diethylacetamide , N-methyl-2-pyrrolidone, pyrrolidone-based solvents such as N-vinyl-2-pyrrolidone, phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, phenol-based solvents such as catechol, tetrahydrofuran, Examples include ether solvents such as dioxane and dioxolan, alcohol solvents such as methanol, ethanol and butanol, cellosolves such as butyl cellosolve and hexamethylphosphoramide, and γ-butyrolactone. The use of these alone or as a mixture is preferred, further xylene, aromatic hydrocarbons such as toluene can be used. The solvent is not particularly limited as long as it dissolves the polyamic acid.

It is essential that the resin layer of the present invention contains a polyimide or a polyamic acid. However, in order to control the resistance value, thermal conductivity, resistance to ultraviolet light, moisture resistance, and the like, a resin layer is generally used. The method used for improving the properties of the insulating resin can be applied. For example, in order for a polyimide belt to exhibit intermediate transfer capability, its volume resistance value should be 1 × 10 ⁶ to 10 ¹⁵ Ω · cm, preferably 1 × 10 ⁷ to 10 ¹⁵ Ω · cm.
^It is extremely important to control it within the range of ¹⁰ Ωcm,
As a specific method for realizing this, a method of mixing an appropriate amount of conductive inorganic powder such as carbon black into a resin is most effective. In addition to carbon black, small-diameter metal particles, metal oxide particles, titanium oxide, various inorganic particles, and whiskers formed of a conductive material such as metal oxide can provide the same effect. . Further, an ionic conductive substance such as LiCl can be added. Further, for example, by introducing a thermally conductive inorganic powder into the polyimide belt resin, its heat fixing ability can be improved. The thermal conductive inorganic powder is not particularly limited as long as it is an inorganic powder having a thermal conductive function, and examples thereof include aluminum nitride, boron nitride, alumina, silicon carbide, silicon, silica, and graphite. Among them, boron nitride is preferable because it has a high heat conduction function, exhibits a releasing effect, is chemically stable, and is harmless. The above-mentioned inorganic powder can be appropriately selected depending on the use of the polyimide belt by using a single or a plurality of mixed systems. If the amount of the inorganic powder is too small, the effect cannot be sufficiently exhibited, and if the amount is too large, the strength of the resin tends to decrease. From this viewpoint, the inorganic powder is preferably blended in an amount of 5 to 60 parts by weight based on 100 parts by weight of the resin solids. It is also possible to polish the surface in order to regulate the unevenness of the belt surface and the thickness of the belt. Examples of the polishing method include emery paper, an iron file, a grinder, and the like, but are not in this range.

In this polyimide belt, a layer having another component may be appropriately laminated on the outer layer. Examples of the outer layer include poly (tetrafluoroethylene) and poly (vinylidene fluoride), but are not limited thereto. As the fiber substrate according to the present invention,
Any of various conventionally known reinforcing fibers such as glass fiber, carbon fiber, Kevlar fiber, ceramic fiber, metal fiber, aramid fiber, and boron fiber can be used, and in particular, carbon fiber and glass fiber may be used as the resin composition. It is preferably adopted because of its excellent affinity with. There is no particular limitation on the fiber length, the amount of the fiber added, and the like. Plain weave, satin weave, twill weave, and the like are conceivable as the weaving method of the cylindrical fiber base material, but are not limited thereto. Next, an example of a specific method of forming a polyimide belt will be described. The fiber woven into a cylindrical shape is impregnated with a solution containing a polyimide precursor. The fibers woven into a cylindrical shape are impregnated with a resin and dried to form a framework of a polyimide belt obtained by drying.
The amount of resin impregnated in the fiber woven into the cylindrical shape is desirably set to such an extent that the fiber layer does not excessively exist on the surface after the solvent is removed in consideration of the characteristics required for the molded article. The viscosity of the polyimide precursor solution is not particularly limited as long as the fiber can be impregnated. Preferably, the viscosity is 1 to 100,000 cpoise at 25 ° C. For the purpose of preventing the generation of voids due to air bubbles, it may be appropriately selected to remove air bubbles in the manner of centrifugal defoaming. Next, the solvent is removed by evaporation. To remove the solvent by volatilization, the cylindrical fiber may be heated or vacuum dried by blowing hot air, irradiating infrared rays, or the like. The heating temperature is preferably equal to or lower than the boiling point of the solvent in order to surely prevent the generation of voids, but is not limited thereto. There are no particular restrictions on the conditions for vacuum drying. Next, by heating the fiber impregnated with the polyimide precursor solution, the imidization reaction proceeds until the imide conversion reaches 60% or more, preferably 80% or more. At the time of imidation, insertion of the cylindrical fiber into a cylindrical mold or a cylindrical mold may be appropriately selected. In that case, a release agent may be used for the purpose of ensuring the release property after imidization in the mold. Finally, the system is cooled, and the desired polyimide belt can be obtained. Furthermore, it is also possible to apply a polyimide precursor solution to one or both of the inner periphery and the outer periphery of the polyimide belt obtained in this manner, to dry and imidize the solution, and to form an outer layer or an inner layer. . Further, another resin layer such as a fluorine-based resin may be provided on the outer layer or the inner layer.

[0010] Instead of impregnating the solution into the cylindrical fiber, it is also possible to impregnate the solution into the long fiber, and then form it into a cylindrical shape and dry and imidize it. In this case, it is possible to apply a filament winding method, a vacuum injection method, an injection molding method, or the like in a manner of molding the fiber-reinforced plastic. The molded body manufactured by such a vacuum injection method or an injection molding method can have not only a belt mold in the present invention but also an arbitrary shape according to the shape of the mold.

[0011]

Next, an embodiment of a method for manufacturing a polyimide belt according to the present invention will be described in more detail.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention is as follows.

(Example) 1500 g of dimethylformamide (DMF) sufficiently dehydrated with a molecular sieve was placed in a vessel equipped with stirring blades, 200 g of 4,4'-diaminodiphenyl ether was added, and the mixture was stirred until it was completely dissolved. . This system was cooled to about 0 ° C., and 218 g of pyromellitic dianhydride was gradually added, followed by thorough stirring. When the viscosity of the system becomes about 3000 poise, stop stirring,
A polyamic acid solution was obtained. Next, 60 g of a metal filler TM-200 manufactured by Otsuka Chemical Co., Ltd. and 300 g of DMF were placed in another container, stirred well, and further applied to an ultrasonic disperser to uniformly disperse the metal filler in the dispersion. Also,
In another container, carbon black 303 manufactured by Mitsubishi Chemical Corporation
OB (15 g) and DMF (300 g) were added, mixed well, and placed in an ultrasonic dispersing machine. 324 g and 45 g of the metal filler dispersion and the carbon black dispersion obtained above were collected in the same beaker, respectively, and thoroughly stirred. In this beaker, the polyamic acid solution 30 obtained above was placed.
0 g was dissolved and stirred well. 300 g of DMF was further added to this mixed solution, and the viscosity of the solution was adjusted to about 2000 cpoise at 25 ° C. The polyamic acid-metal filler-carbon black mixed solution thus obtained was impregnated into a cylindrical fiber having a length of 330 mm and a diameter of 80 mm made of carbon fiber having a diameter of 5 μm. Next, the cylindrical fiber is sealed in a vacuum dryer,
Vacuum drying was performed gradually over 4 hours under a pressure of 1 torr so that voids did not occur. Next, the cylindrical fiber was put into an oven together with the mold, and the temperature was raised from room temperature to 380 ° C. over about 30 minutes to allow the imidization reaction to proceed. After cooling the system, the surface of the polyimide belt was polished with emery paper. From the polyimide belt obtained by the above-mentioned means, 30 test pieces were randomly cut out, and the thickness and the tear propagation strength were measured. The thickness was measured using a film thickness gauge capable of measuring a minimum unit of 0.01 μm. The tear propagation strength is a parameter that most notably indicates the toughness of the film, and is obtained by dividing a straight line in a part of the film and dividing the load when the tear is torn in the vertical direction by the thickness of the film. The value obtained. The tear propagation strength was measured at a tear speed of 200 mm / sec using an Autograph S-100-C manufactured by Shimadzu Corporation equipped with a load cell capable of measuring a maximum of 100 gf. As a result, the thickness of the obtained polyimide belt was 70 ± 2 μm, and the tear propagation strength was 1 kg ± 200 g / mm. The surface roughness of this test piece was measured with a surface roughness meter manufactured by Seiko Instruments Inc., and the average surface roughness was 5 μm. (Comparative Example 1) The polyamic acid-metal filler-carbon black mixed solution obtained in the above-described method for producing a polyimide belt was poured into a cylindrical SUS mold having an inner diameter of 90 mm and a length of 450 mm, thereby forming the cylindrical metal. The solution was applied to the entire inner surface of the mold. The releasability after belt molding was improved by applying a fluorine-based release agent on the inner surface of the cylindrical mold in advance. Next, a mandrel having a diameter of 30 mm was pierced and fixed so that the center of the mandrel coincided with the center of the cylindrical mold.
A SUS ring mold having a φ and a liquid contacting part angle of 30 ° was installed. Next, the ring-shaped mold is moved in parallel by injecting compressed air obtained by an air compressor into the cylindrical mold, and a 0.5 mm-thick polyimide resin precursor solution film is formed on the inner surface of the mold. Was molded. This mold coated with the polyimide resin precursor solution is placed in a vacuum dryer, and the mold is rotated for 1 ton while rotating the mold so that the solution does not accumulate below.
Dry at rr for 4 hours. Next, the mold was placed in an oven, and the temperature was raised from room temperature to 380 ° C. over about 30 minutes, whereby the imide conversion reaction was allowed to proceed. Thereafter, the mold was allowed to cool at room temperature, the resin was removed from the mold, and the desired polyimide belt was obtained.

Thirty test pieces were randomly cut from the polyimide belt thus obtained, and the tear propagation strength was measured. As a result, the tear propagation strength was 180 ±
It was 50 g / mm.

Although the method for producing a polyimide belt according to the present invention has been described above, the present invention is not limited to the above-described embodiment. Needless to say, the present invention can be implemented in various modified forms within the described range.

[0016]

As described above, the method for producing a polyimide belt according to the present invention exhibits the following effects by impregnating a cylindrical precursor fiber with a polyimide precursor solution, followed by drying and imidization. .

First, it is excellent in cost. That is, as described above, the polyimide belt manufacturing method of the present invention does not require a mold that leads to an increase in cost such as a jig for clearance adjustment, provided that even a cylindrical fiber impregnated with the polyimide precursor solution is prepared, The production yield is also very high. Therefore, a polyimide belt can be manufactured at a remarkably low cost as compared with the conventional method.

Second, the mechanical strength is dramatically improved.
That is, in the method for producing a polyimide belt of the present invention, the polyimide resin is a fiber-reinforced plastic, so that mechanical strength, particularly toughness, is significantly improved. As a result, the life of the parts is dramatically improved, and as a result, the cost of the apparatus is reduced.

Third, it can be manufactured easily and easily. That is, the method for producing a polyimide belt of the present invention is an application of a technique conventionally used for fiber-reinforced plastics, and can be easily and easily produced. As described above, the effects exhibited by the present invention are remarkable and large, for example, all the problems existing in this type of conventional example are solved.

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Claims (5)

[Claims] 1. A method for producing a polyimide belt, comprising impregnating a fiber woven in a cylindrical shape for preparing a polyimide belt basic structure with a polyimide precursor solution, followed by drying and imidization. 2. The method for producing a polyimide belt according to claim 1, wherein the polyimide precursor solution contains 5 to 60 parts by weight of the inorganic powder relative to 100 parts by weight of the resin solid component. 3. The method for producing a polyimide belt according to claim 1, wherein the thickness of the belt is controlled by polishing. 4. The method for producing a polyimide belt according to claim 1, wherein the fiber substrate is at least one of glass fiber, carbon fiber, Kevlar fiber, ceramic fiber, metal fiber, and aramid fiber. 5. The method for producing a polyimide belt according to claim 1, wherein the weave of the cylindrical fiber base material is any of plain weave, satin weave, and twill weave.