JP4571205B2 - Method for manufacturing semiconductive belt, and semiconductive belt obtained by this method - Google Patents

Description

  The present invention relates to a semiconductive belt excellent in environmental stability and durability of electrical characteristics and suitable for an intermediate transfer belt for an image in an electrophotographic recording apparatus, a transfer conveyance belt for a recording sheet of the image, and the like.

  In devices such as copying machines, laser printers, video printers, facsimiles, and multi-function printers that form and record images using electrophotographic methods, the image carrier such as a photosensitive drum may be coated with toner to improve the life of the device. A method of avoiding a method of directly fixing an image formed via a recording agent on a recording sheet, and a method of transferring the image on the image carrier to the intermediate transfer belt once and fixing it on the recording sheet has been studied. Further, a transfer system that transfers the image to a recording sheet and also serves to convey the sheet has been studied.

Conventionally, as a semiconductive belt that can be used for the above intermediate transfer belt or the like, one having a volume resistivity of 1 to 10 ¹³ Ωcm by blending a conductive filler with a polyimide film has been known (Japanese Patent Laid-Open No. 5-77252). Issue gazette). This is because a polyimide film is used, and a semiconductive belt using a film made of vinylidene fluoride, an ethylene / tetrafluoroethylene copolymer, polycarbonate, or the like (Japanese Patent Laid-Open Nos. 5-200904 and 5-95). No. 345368, JP-A-6-95521), that is, insufficient mechanical properties such as strength, friction resistance, and wear resistance cause cracks in the belt end or the like, or deform and transfer due to a load during driving. It overcomes problems such as image deformation.

  However, the conventional semiconductive belt made of a polyimide film has a problem that the environmental stability and durability of electrical characteristics are poor and cannot be satisfied practically. That is, when the electrical characteristics such as surface resistivity fluctuate greatly in the external environment such as temperature and humidity, or the electrical characteristics fluctuate greatly after long-term use, for example, when used as the above intermediate transfer belt or transfer conveyance belt In addition, there are problems such as uneven transfer in the toner image transferred and developed on the recording sheet, and poor separation when the recording sheet conveyed while being transferred is separated from the belt.

  The present invention takes advantage of excellent mechanical properties such as the above-mentioned strength of the polyimide film, is excellent in environmental stability of electrical properties such as surface resistivity and hardly fluctuates depending on the external environment, and is an intermediate transfer belt for an electrophotographic recording apparatus. Development of a semiconductive belt that can transfer a good image to a recording sheet without deformation or uneven transfer of the toner image even when it is used as a transfer conveying belt, and can maintain the ability to separate the conveying recording sheet for a long time Is an issue.

The present invention
A dispersion is prepared by dispersing only carbon black in a solvent, and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and diamine are dissolved in the dispersion and polymerized to form 3,3 ′. , 4,4′-biphenyltetracarboxylic dianhydride only component or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride 3,3 ′, 4 , 4′-biphenyltetracarboxylic dianhydride is prepared as a polyamic acid solution having a composition containing 60 mol% or more of the acid component, and the polyamic acid solution is formed into a seamless belt shape. the polyamic acid was imidization, electronic copy made of a polyimide film of hygroscopic swelling coefficient only the carbon black was dispersed ^{2.0 / 10 5 cm / cm /} % RH or less is monolayer Obtaining a recording apparatus belt, a manufacturing method of the electrophotographic recording apparatus belt,
The carbon black has a volume resistivity of 1 × 10 ⁹ to 1 × 10 ¹⁶ Ωcm and a surface resistivity of 1 × 10 ¹⁰ to 1 × 10 ¹⁷ Ω at 25 ° C. and 60% RH of the polyimide film, and 30 A method for producing a belt for an electrophotographic recording apparatus, wherein the belt is uniformly dispersed in the solvent so that the fluctuation range based on the common logarithm of the surface resistivity at 10 ° C. and 15% RH is 1.0 or less. ,
Is to provide.

  According to the present invention, the semi-conductivity is excellent in the environmental stability of the electrical properties such as surface resistivity and the electrical properties are not easily changed by the external environment while taking advantage of the excellent mechanical properties such as the strength and difficult stretchability of the polyimide film. A belt can be obtained, and when used as an intermediate transfer belt or transfer conveyance belt in an electrophotographic recording apparatus, a good image can be transferred to the recording sheet without deformation or transfer unevenness of the recorded image due to toner or the like, and the conveyance recording sheet Thus, it is possible to obtain a belt that maintains the performance of separating the toners for a long time.

The semiconductive belt according to the present invention has a volume resistivity of 10 ⁹ to 10 ¹⁶ Ωcm at 25 ° C. and 60% RH, a surface resistivity of 10 ¹⁰ to 10 ¹⁷ Ω, and 30 ° C. and 85% RH. It consists of a polyimide film having a fluctuation range of 1.0 or less based on the common logarithm of the surface resistivity at 10 ° C. and 15% RH.

  The polyimide film is formed by, for example, developing a polyamic acid solution obtained by polymerizing tetracarboxylic dianhydride or its derivative and diamine in a solvent in an appropriate manner, and drying the film to form a film. And the molded product can be heat-treated to convert the polyamic acid into an imide.

Any suitable tetracarboxylic dianhydride or diamine for forming a polyamic acid may be used. Incidentally, examples of the tetracarboxylic dianhydride include those represented by the following general formula.
(Wherein R is a tetravalent aromatic group, aliphatic group, cycloaliphatic group, a composite group thereof, or a group having a substituent).

  Specific examples of the tetracarboxylic dianhydride include pyromellitic dianhydride (PMDA), 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4. '-Biphenyltetracarboxylic dianhydride (BPDA), 2,3,3', 4'-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride or 1,2 , 5,6-naphthalenetetracarboxylic dianhydride.

  In addition, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2′-bis (3,4-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydrides, perylene-3,4,9,10-tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, ethylenetetracarboxylic dianhydride, etc. Specific examples are given.

  On the other hand, examples of diamines include 4,4′-diaminodiphenyl ether (DDE), 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, and 3,3′-dichlorobenzidine. 4,4'-aminodiphenyl sulfide, 3,3'-diaminodiphenylsulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine (PDA), 3,3'-dimethyl-4,4 ' -Diaminobiphenyl and benzidine.

  3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 4,4′-diaminophenylsulfone, 4,4′-diaminodiphenylsulfide, 4,4′-diaminodiphenylpropane, 2,4-bis (Β-amino-t-butyl) toluene, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl-δ-aminophenyl) benzene, bis-p- (1,1- Examples of the diamine include dimethyl-5-aminopentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, and p-xylylenediamine.

  Furthermore, di (p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylenediamine, 3-methylheptamethylenediamine, 4,4-dimethylhepta Methylenediamine, 2,11-diaminododecane, 1,2-bis- (3-aminopropoxy) ethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2, 5-dimethylheptamethylenediamine is also an example of the diamine.

In addition, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 1,12- Diaminooctadecane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane and piperazine, H ₂ N (CH ₂ ) ₃ O (CH ₂ ) ₂ O (CH ₂ ) NH ₂ , H ₂ N (CH ₂ ) ₃ S (CH ₂ ) ₃ NH ₂ , H ₂ N (CH ₂ ) ₃ N (CH ₃ ) (CH ₂ ) ₃ NH _2, etc. are also examples of the diamine.

  Although an appropriate solvent can be used as a solvent for the above-described tetracarboxylic dianhydride and the like to undergo a polymerization reaction with a diamine, a polar solvent can be preferably used in view of solubility. Incidentally, examples of the polar solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylformamide, N, N-dialkylamides such as N, N-diethylacetamide, N, N -Dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone (NMP), pyridine, dimethylsulfone, tetramethylenesulfone, dimethyltetramethylenesulfone, and the like.

  In particular, polar solvents that can be easily removed from the polyamic acid solution by appropriate measures such as evaporation, substitution, and diffusion can be preferably used. As the solvent, for example, phenols such as cresol, phenol and xylenol, benzonitrile, dioxane, hexane, benzene, toluene and the like other than water can be used together as necessary. The use of water is not preferable because the produced polyamic acid is hydrolyzed to lower the molecular weight, and the strength of the polyimide is easily lowered.

  In preparing the polyamic acid, one or more tetracarboxylic dianhydrides and their derivatives, diamines, polar solvents and other solvents can be used. The ratio of tetracarboxylic dianhydride and the like to diamine is generally approximately equimolar, but is not limited thereto. The monomer concentration at the start of the reaction can be appropriately determined depending on the reaction conditions and the like, but is generally about 5 to 30% by weight, and the reaction temperature is preferably 80 ° C. or lower, especially 5 to 50 ° C.

As the reaction proceeds, the viscosity of the solution increases. In the present invention, a polyamic acid solution in which the reaction has proceeded to a logarithmic viscosity η of 0.5 or more is preferred from the viewpoint of improving the heat resistance of the resulting belt. The reaction time required to obtain such a polymerized polyamic acid solution is typically 0.5 to 10 hours based on the above reaction conditions. The logarithmic viscosity η can be calculated by the following equation using the polyamic acid solution drop time t ₁ and the solvent drop time t ₀ measured with a capillary viscometer. η = In (t ₁ / t ₀ ) / C (where C is the polyamic acid concentration (g / dl) in the solution)

The polyimide film used for forming the semiconductive belt has a volume resistivity of 10 ⁹ to 10 ¹⁶ Ωcm and a surface resistivity of 10 ¹⁰ to 10 ¹⁷ Ω in a reference state, that is, 25 ° C. and 60% RH, and The fluctuation range based on the common logarithm of the surface resistivity at 30 ° C. and 85% RH and 10 ° C. and 15% RH is 1.0 or less. Accordingly, it is possible to obtain a semiconductive belt excellent in environmental stability of electrical characteristics while satisfying electrical characteristics required for an intermediate transfer belt and a transfer conveyance belt of an electrophotographic recording apparatus.

When the volume resistivity in the reference state is less than 10 ⁹ Ωcm or the surface resistivity is less than 10 ¹⁰ Ω, an excessive current is generated between the image carrier and the intermediate transfer belt to transfer the recording agent to the intermediate transfer belt or the like. Returning to the image carrier, it becomes difficult to form an accurate image. On the other hand, when the volume resistivity in the standard state exceeds 10 ¹⁶ Ωcm or the surface resistivity exceeds 10 ¹⁷ Ω, the intermediate transfer is performed when an image formed by the recording agent formed on the image carrier is transferred to an intermediate transfer belt or the like. A discharge phenomenon occurs when the belt, etc., is remarkably charged and leaves the image carrier, and the recording agent transferred to the intermediate transfer belt, etc., is scattered by the peeling discharge, which makes it difficult to form an accurate image. In the case of the belt, the discharge through the front surface and / or the back surface of the belt does not proceed smoothly, and the separation of the recording sheet to be conveyed tends to occur.

A preferable semiconductive belt (intermediate transfer belt) for the purpose of only intermediate transfer from the viewpoint of accurate image formation by transfer of the above-mentioned good recording agent has a volume resistivity of 10 ⁹ to 10 ^{9 in the} standard state. It consists of a 10 ¹² Ωcm polyimide film. Also, in the case of a semiconductive belt (transfer conveyor belt) that doubles the transfer of an image to a recording sheet and the conveyance of the recording sheet, the reference state can be improved in terms of the accuracy of image formation and the separation of the recording sheet. What consists of a polyimide film whose volume resistivity is 10 < ¹³ > -10 < ¹⁶ > (omega | ohm) cm is preferable.

  To achieve the above-described volume resistivity and surface resistivity, a polyimide film containing a conductive filler can be used as necessary. Examples of the conductive filler include carbon black such as ketjen black and acetylene black, metal such as aluminum and nickel, metal oxide compound such as tin oxide and conductive or semiconductive powder such as potassium titanate, polyaniline, One or two or more suitable materials such as a conductive polymer such as polyacetylene can be used, and the type is not particularly limited.

  The average particle size of the conductive filler to be used is not particularly limited, and those having a smaller particle size can be preferably used in order to suppress variation in electrical characteristics due to uneven distribution. In general, particles having an average particle diameter of 5 μm or less, especially 3 μm or less, particularly 5 mμ to 0.02 μm based on primary particles can be preferably used.

  The amount of the conductive filler used can be appropriately determined according to the type, particle size, dispersibility, and the like from the viewpoint of achieving the above-described electrical characteristics. Generally, from the viewpoint of preventing deterioration of mechanical properties such as strength in a polyimide film, use of 25 parts by weight or less, especially 1 to 20 parts by weight, especially 3 to 15 parts by weight per 100 parts by weight of polyimide (solid content) An amount is preferred.

  The amount of conductive filler used in the polyimide film is preferably as small as possible from the standpoint of maintaining the mechanical properties such as strength described above. Carbon black such as ketjen black is preferred from the point of achieving the electrical properties described above with a small amount of use. Etc. can be preferably used. In this case, the electrical characteristics described above can be achieved even when the amount used is less than 5 parts by weight, especially 1 to 4 parts by weight per 100 parts by weight of polyimide (solid content).

  For example, when preparing the above-described polyamic acid, the conductive filler is mixed in the polyimide film by mixing and dispersing the conductive filler in an appropriate mixer such as a planetary mixer, a bead mill, or a three roll. , A method of subjecting it to a polymerization treatment, or a method of mixing and dispersing or dissolving a conductive filler in a preliminarily prepared polyamic acid solution with an appropriate mixer, and a method of subjecting it to film formation. Can be done.

  In addition, when the conductive filler is blended in the solution for preparing the polyamic acid, first, the conductive filler is first added to the solvent by an appropriate method such as ball mill or ultrasonic wave from the viewpoint of preventing variation in electrical characteristics due to uniform dispersion. A method in which tetracarboxylic dianhydride or a derivative thereof and a diamine are dissolved in the dispersion and then subjected to polymerization treatment can be preferably applied.

The polyimide film that may contain a conductive filler that can be preferably used for forming the semiconductive belt according to the present invention has a hygroscopic swelling coefficient of 2.0 / 10 ⁵ cm / cm /% RH or less. As a result, the environmental stability of the electrical characteristics, especially the electrical characteristics that the fluctuation range based on the common logarithm of the surface resistivity at 30 ° C., 85% RH and 10 ° C., 15% RH is 1.0 or less is advantageously achieved. can do.

  That is, according to the knowledge of the present inventors, as the swelling coefficient due to moisture absorption increases, the rate of change in electrical resistance due to environmental fluctuations tends to increase. This is due to the change in the distance between the conductive fillers based on the expansion due to moisture absorption and the shrinkage due to drying. It can be understood as a result of affecting the change in electrical resistance, and it is considered that the moisture absorption swelling coefficient has a greater effect on the change in electrical resistance due to environmental fluctuations than the moisture absorption rate.

  Therefore, a polyimide having a small hygroscopic swelling coefficient can be advantageously used to suppress changes in electrical resistance due to environmental fluctuations. From this point, the present inventors have also found that a polyimide having the above-described BPDA as a monomer component provides a polyimide having a small hygroscopic swelling coefficient.

The above-mentioned polyimide having a hygroscopic swelling coefficient of 2.0 / 10 ⁵ cm / cm /% RH or less can be obtained by setting the component comprising BPDA to 50 mol% or more of the total acid component. Such a composition is, for example, a copolymer system using 50 mol% or more of BPDA as a tetracarboxylic dianhydride when preparing a polyamic acid solution, or a polyamic acid containing BPDA as a monomer component and other tetracarboxylic dianhydrides. Can be obtained by an appropriate method such as a method in which the polyamic acid having a monomer component is mixed at a ratio of BPDA component to 50 mol% or more of the total tetracarboxylic dianhydride component.

  In view of the decrease in the hygroscopic swelling coefficient, the higher the content of the BPDA component, the better. Especially, the film is formed of polyimide having a composition containing 55 mol% or more, particularly 60 to 100 mol% of the acid component comprising BPDA. It is preferable. In the above description, the relationship between the moisture absorption rate and the moisture absorption swelling coefficient varies depending on the type of polymer, and it is difficult to assume a correlation in which one can be inferred from the other.

  As described above, the polyimide film can be obtained by appropriately developing a polyamic acid solution and forming it into a film. The film thickness can be appropriately determined according to the purpose of use of the semiconductive belt. In general, from the viewpoint of mechanical properties such as strength and flexibility, the thickness is 5 to 500 μm, especially 10 to 300 μm, particularly 20 to 200 μm.

  The semiconductive belt can be formed by forming a polyimide film having the above-described electrical characteristics into a desired belt shape. In that case, a polyimide film composed of two or three or more overlapping layers composed of the same or different layers can also be used. When the target belt is ring-shaped, it can be formed by an appropriate connection method such as an adhesive method using an adhesive at the film end or a seamless ring belt. The ring-shaped seamless belt has an advantage that an arbitrary portion can be set as a rotation start position without a thickness change due to superposition, and a control mechanism for the rotation start position can be omitted.

  The above-described seamless belt is formed by, for example, a method in which a solution of polyamic acid is coated on the inner peripheral surface or outer peripheral surface of a mold by a dipping method, a centrifugal method, a coating method, or a method in which a casting mold is filled. Conventionally, such as a method of spreading in a ring shape by an appropriate method, drying the formed layer to form a belt shape, heat-treating the molded product to convert the polyamic acid into an imide, and recovering from the mold It can be carried out by an appropriate method in conformity (Japanese Patent Application Laid-Open No. 61-95361, Japanese Patent Application Laid-Open No. 64-22514, Japanese Patent Application Laid-Open No. 3-180309, etc.). In forming the seamless belt, an appropriate treatment such as mold release treatment or defoaming treatment can be performed.

  The semiconductive belt according to the present invention can be used for various applications according to the prior art. In particular, since it is excellent in mechanical characteristics and electrical characteristics, it can be preferably used as a belt for intermediate transfer of an image in an electrophotographic recording apparatus, a belt for transfer of a recording sheet that also serves as transfer, and the like. In that case, an appropriate printing sheet such as a paper-based sheet or a plastic sheet can be used as the recording sheet, and an appropriate recording agent for forming an image on the recording sheet can be used that can be subjected to adhesion treatment via static electricity. sell.

Example 1
NMP1674 parts (parts by weight, the same shall apply hereinafter) 16.1 parts (corresponding to 4% by weight of polyimide) of dry carbon black (Vulcan XC, manufactured by Cabot Corp.) are mixed for 6 hours at room temperature in a ball mill. BPDA (294.2 parts) and PDA (108.2 parts) were dissolved in the obtained uniform dispersion and stirred in a nitrogen atmosphere at room temperature for 4 hours to effect a polymerization reaction to obtain a polyamic acid solution.

  Next, the polyamic acid solution was applied to the inner peripheral surface of a drum mold having an inner diameter of 330 mm and a length of 500 mm via a dispenser to a thickness of 400 μm, and rotated at 1500 rpm for 10 minutes to obtain a spread layer having a uniform thickness. While rotating at 250 rpm, hot air of 60 ° C. was blown from the outside of the drum mold for 30 minutes, then heated at 150 ° C. for 60 minutes, then heated to 300 ° C. at a rate of 2 ° C./minute and heated at that temperature for 30 minutes. Then, the solvent was removed, the dehydrated ring-closing water was removed, and the imide conversion was performed. The resulting mixture was cooled to room temperature and peeled from the mold to obtain a seamless semiconductive belt having a thickness of 73 to 78 μm.

Example 2
A 20 wt% NMP solution in which 176.5 parts of BPDA / 87.2 parts of PMDA (molar ratio 6/4) and 200.0 parts of DDE are dissolved is stirred in a nitrogen atmosphere at room temperature for 4 hours to effect a polymerization reaction, and a polyamic acid having a viscosity of 2000 poise A thickness of 74 was obtained in the same manner as in Example 1 except that the polyamic acid solution and 9.3 parts of Vulcan XC (corresponding to 2% by weight with respect to polyimide) were kneaded with a three roll and the uniform dispersion was used. A seamless semiconductive belt of ˜79 μm was obtained.

Example 3
A seamless semiconductive belt having a thickness of 76 to 80 μm was obtained in the same manner as in Example 1 except that the amount of Vulcan XC used was equivalent to 3.5% by weight based on the polyimide.

Example 4
Instead of Vulcan XC, acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.) and ketjen black (Ketjen Black EC, manufactured by Lion Co., Ltd.) were each used in an amount equivalent to 3% by weight (total of 6% by weight) with respect to polyimide. According to Example 1, a seamless semiconductive belt having a thickness of 76 to 80 μm was obtained.

Example 5
A seamless semiconductive belt having a thickness of 74 to 80 μm was obtained in the same manner as in Example 2 except that the use ratio of BPDA / PMDA was changed to 4/6 mol.

Example 6
A seamless semiconductive belt having a thickness of 74 to 80 μm was obtained in the same manner as in Example 1 except that the amount of Vulcan XC used was equivalent to 6% by weight based on the polyimide.

Example 7
A seamless semiconductive belt having a thickness of 74 to 80 μm was obtained in the same manner as in Example 1 except that Vulcan XC was used in an amount corresponding to 2.5% by weight based on the polyimide.

Evaluation Test The following characteristics of the semiconductive belt obtained in the above example were examined.
Volume resistivity Volume resistivity at 25 ° C. and 60% RH was measured with Hiresta IP MCP-HT260 (manufactured by Mitsubishi Oil Chemical Co., Ltd., probe: HR-100) at an applied voltage of 100 V and a measurement value of 1 minute value.

Surface resistivity and fluctuation range (△ log)
Investigate the surface resistivity at 10 ° C, 15% RH, 25 ° C, 60% RH (reference state) and 30 ° C, 85% RH by Hiresta IP MCP-HT260 under an applied voltage of 250V and 1 minute measurement conditions. , 30 ° C., 85% RH (a) and 10 ° C., 15% RH (b), the fluctuation range based on the common logarithm of surface resistivity (Δlog: a−b) was determined. The reference values a and b are average values.

Hygroscopic swelling coefficient, hygroscopicity The product dried for 1 hour at 120 ° C, absorbed at 25 ° C and 100% RH for 24 hours, before and after moisture absorption (L ₀ , W ₀ ) and after moisture absorption (L, W) The change (L−L ₀ = ΔL) and the weight change (W−W ₀ = ΔW) were determined and calculated from the following formula.
Hygroscopic swelling coefficient = ΔL / 100L ₀
Moisture absorption rate = △ W / W ₀ × 100

  Tensile strength and elongation The punched specimen (width 5 mm) of dumbbell No. 3 was examined for tensile strength (speed 100 mm / min) and elongation at break.

Image transfer property, paper separation property The semiconductive belt obtained in the above example is incorporated into a commercially available copying machine as an intermediate transfer belt (belt method A) or transfer conveying belt (belt method B), and is a recording sheet made of plain paper. A 10,000-sheet printing test was conducted. The test was performed by changing the environmental conditions from 10 ° C. and 15% RH (low temperature and low humidity) to 30 ° C. and 85% RH (high temperature and high humidity) while printing 5000 sheets. Also, the evaluation is good when a clear and accurate image is obtained by good transfer in all 10,000 sheets of test, and when no paper separation failure occurs, transfer failure, unclear image, inaccurate A case where an image was obtained and a case where a paper separation failure occurred were regarded as defective.

The results are shown in the following table.

  From the table, while maintaining the excellent strength and difficult stretchability (hard deformation) of the polyimide film, there is little variation in the volume resistivity and surface resistivity in the surface, and the surface resistivity is less likely to vary depending on the external environment, When used as an intermediate transfer belt or transfer / conveying belt in an electrophotographic recording apparatus, it can transfer a good image to a recording sheet without deformation or uneven transfer of the toner image, and can separate the conveyed recording sheet satisfactorily for a long time. You can see that it lasts.

Claims (1)

A dispersion is prepared by dispersing only carbon black in a solvent, and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and diamine are dissolved in the dispersion and polymerized to form 3,3 ′. , 4,4′-biphenyltetracarboxylic dianhydride only component or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and pyromellitic dianhydride 3,3 ′, 4 , 4′-biphenyltetracarboxylic dianhydride is prepared as a polyamic acid solution having a composition containing 60 mol% or more of the acid component, and the polyamic acid solution is formed into a seamless belt shape. the polyamic acid was imidization, electronic copy made of a polyimide film of hygroscopic swelling coefficient only the carbon black was dispersed ^{2.0 / 10 5 cm / cm /} % RH or less is monolayer Obtaining a recording apparatus belt, a manufacturing method of the electrophotographic recording apparatus belt,
The carbon black has a volume resistivity of 1 × 10 ⁹ to 1 × 10 ¹⁶ Ωcm and a surface resistivity of 1 × 10 ¹⁰ to 1 × 10 ¹⁷ Ω at 25 ° C. and 60% RH of the polyimide film, and 30 A method for producing a belt for an electrophotographic recording apparatus, wherein the belt is uniformly dispersed in the solvent so that the fluctuation range based on the common logarithm of the surface resistivity at 10 ° C. and 15% RH is 1.0 or less. .