JP2003255726A - Semiconductor belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductive belt in which surface resistivity of an outer surface can be easily adjusted while maintaining volume resistivity of the whole and the problem hardly occurs and to provide a method for manufacturing the semiconductive belt. <P>SOLUTION: In the semiconductor belt which is made of a polyimide resin containing a conductive filler and has seamless structure, an outer surface part has a region of 1 to 10 μm thickness in which concentration of the conductive filler is discontinuously different from the concentration in other parts and difference between surface resistivity of the outer surface and surface resistivity of the inner surface is ≥1.5 based on common logarithms. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive belt which can be suitably used as an intermediate transfer belt for an image in an electrophotographic recording apparatus or the like, or a print sheet transfer belt (transfer transfer belt) also used for the intermediate transfer. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a copying machine, a laser printer, a video printer, a facsimile machine, a composite machine thereof, and the like have been known as an electrophotographic recording apparatus for forming and recording an image by an electrophotographic system. In this type of device, in order to avoid the system in which an image formed by a recording material such as toner is directly fixed on an image carrier such as a photosensitive drum on a print sheet for the purpose of improving the life of the device, the image carrier is avoided. A method in which the above image is once transferred to an intermediate transfer belt and then fixed on a printing sheet is under study. In addition, for the purpose of downsizing of the apparatus, a system in which the above-mentioned intermediate transfer belt also serves as conveyance of a printing sheet is being studied.

As a semi-conductive belt which can be used as the above-mentioned intermediate transfer belt, it has been known that a polyimide resin film is mixed with a conductive filler to have a volume resistivity of 1 to 10 ¹³ Ω · cm. (See JP-A-5-77252). This is because a polyimide resin film is used, so that a semiconductive belt using a film made of vinylidene fluoride, an ethylene / tetrafluoroethylene copolymer, a polycarbonate, etc., which has been used up to then (Japanese Patent Laid-Open No. 5-20.
0904, JP-A-5-345368, and JP-A-6-95521), that is, the mechanical properties such as strength and friction / abrasion resistance are insufficient, and cracks occur at the belt end or the like. This overcomes the problem that the transferred image is deformed due to time load.

On the other hand, as a method for lowering the surface resistivity of only the outer surface of the semiconductive belt, there is disclosed in JP-A-61-2028.
As described in Japanese Patent Laid-Open No. 11, a technique is known in which a conductive filler is settled and concentrated on the outer surface by a difference in specific gravity of raw materials in a centrifugal molding method.

[0005]

However, in the semi-conductive belt manufactured in this manner, the surface resistivity varies greatly in the external environment such as temperature and humidity, and the electrical characteristics vary greatly in long-term use. Then, for example, when it is used as the above-mentioned intermediate transfer belt or a conveyor belt which is also used, there is a problem that a separation failure occurs when the printing sheet is separated from the belt.

Further, as described in JP-A-7-156287, by forming a semi-conductive belt with two or more layers and changing the content of the conductive substance in each layer, the outer surface and the inner surface can be changed. There is also known a technique for varying the surface resistivity of the. However, since there is not much difference in the thickness of each layer (the thickness of the outer layer is 20 μm or more), it is difficult to adjust the surface resistivity of the outer surface while maintaining the volume resistivity of the entire layer. Further, the coefficient of thermal expansion of each layer differs depending on the content of the conductive material, and since there is not much difference in the thickness of each layer, distortion and warpage are likely to occur due to residual stress when cooled from the high temperature during imide conversion. There is also a problem.

Therefore, an object of the present invention is to provide a semi-conductive belt which can easily adjust the surface resistivity of the outer surface while maintaining the overall volume resistivity, and which is less likely to cause the above problems, and a method for producing the same. To provide.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have earnestly studied a method for producing a semiconductive belt, a sectional structure of the obtained semiconductive belt, etc. It was found that the above-mentioned object can be achieved by the semiconductive belt having a specific cross-sectional structure obtained by the above, and the present invention has been completed.

That is, the semiconductive belt of the present invention is a semiconductive belt having a seamless structure made of a polyimide resin containing a conductive filler, and the outer surface portion of the semiconductive belt has a concentration of the conductive filler different from that of other portions. It is characterized by having continuously different regions having a thickness of 1 to 10 μm and having a difference in surface resistivity between the outer surface and the inner surface of 1.5 or more based on the common logarithm. Here, the semi-conductive belt has a volume resistivity of 1 to 10 ¹⁶ Ω · cm.

On the other hand, according to the manufacturing method of the present invention, a semiconductive belt having a seamless structure is obtained by performing rotary centrifugal molding and imide conversion using a raw material liquid of a polyimide resin containing a conductive filler. In the manufacturing method of
25 ° C with a B-type viscometer containing a conductive filler in advance
After forming a solidified outer layer having a thickness of 1 to 10 μm on the inner peripheral surface of the mold using a polyamic acid solution having a solution viscosity of 0.01 to 1 Pa · s, the content ratio of the conductive filler is different.
Solution viscosity at 25 ° C measured by a viscometer is 1-1000Pa
The inner layer is formed by rotary centrifugal molding using the polyamic acid solution of s.

In the above, when forming the outer layer,
It is preferable that the polyamic acid solution is spray-coated on the inner peripheral surface of the molding die and dried and solidified while rotating the molding die.

[Operation and Effect] According to the semiconductive belt of the present invention, a region having a thickness of 1 to 10 μm (hereinafter referred to as “concentration of the conductive filler” discontinuously differs from the other part on the outer surface part).
(It may be abbreviated as the outer layer), and because its thickness is thin,
Physical properties such as the volume resistivity and mechanical strength of the whole are less likely to be affected, and the residual stress due to the difference in the coefficient of thermal expansion of each layer is also small. As a result, while maintaining the overall volume resistivity,
It is possible to provide a semiconductive belt in which the surface resistivity of the outer surface can be easily adjusted and the problem due to residual stress does not easily occur.

On the other hand, according to the manufacturing method of the present invention,
After forming a solidified outer layer having a thickness of 1 to 10 μm on the inner peripheral surface of the mold using a polyamic acid solution containing a conductive filler and having a solution viscosity of 0.01 to 1 Pa · s at 25 ° C. measured by a B type viscometer In order to form the inner layer, a region having a thickness of 1 to 10 μm in which the concentration of the conductive filler is discontinuously different from that of the other part can be suitably formed on the outer surface part, and the overall volume resistivity is maintained. However, the surface resistivity of the outer surface can be easily adjusted, and a semiconductive belt in which problems due to residual stress hardly occur can be manufactured.

When the outer layer is formed, when the polyamic acid solution is spray-coated on the inner peripheral surface of the mold and dried and solidified while rotating the mold, a thin outer layer is preferably formed with a uniform thickness. can do.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The semi-conductive belt of the present invention is a seamless semi-conductive belt made of a polyimide resin containing a conductive filler. Such a semi-conductive belt can be obtained, for example, by performing rotational centrifugal molding and imide conversion using a raw material liquid of a polyimide resin containing a conductive filler.

As the raw material liquid of the polyimide resin, for example, a solution of a polyamic acid obtained by polymerizing a tetracarboxylic dianhydride or its derivative and a diamine in a solvent can be used. The polyamic acid is obtained by reacting tetracarboxylic dianhydride or its derivative with approximately equimolar amounts of diamine in an organic solvent, and is usually used in the form of a solution. Such a tetracarboxylic dianhydride is represented by, for example, the following general formula (1).

[0017]

[Chemical 1] (In the formula, R is a tetravalent organic group, which is an aromatic group, an aliphatic group, a cycloaliphatic group, a combination of an aromatic group and an aliphatic group, or a substituted group thereof.) Specific examples of the acid dianhydride include:
Pyromellitic dianhydride (PMDA), 3,3 ', 4
4'-benzophenone tetracarboxylic dianhydride (BP
DA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3', 4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid Dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) ) Propane dianhydride, bis (3,4)
-Dicarboxyphenyl) sulfone dianhydride, perylene-3,4,9,10-tetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride,
Examples thereof include ethylene tetracarboxylic dianhydride.

On the other hand, examples of the diamine include 4,4'-diaminodiphenyl ether (DDE), 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine and 4,4-diamino. Diphenyl sulfide-3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine (PDA),
3,3'-dimethyl-4,4'-biphenyldiamine,
Benzidine, 3,3'-dimethylbenzidine, 3,3 '
-Dimethoxybenzidine, 4,4'-diaminophenyl sulfone, 4,4'-diaminophenyl sulfone, 4,
4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylpropane, 2,4-bis (β-amino-
Tert-butyl) toluene, bis (p-β-amino-tert-butylphenyl) ether, bis (p-β-methyl-δ-
Aminophenyl) benzene, bis-p- (1,1-dimethyl-5-amino-pentyl) benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di (P-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2 ，
11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 2,5-Dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,11-diaminododecane, 2,17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10- Diamino-1,10-
Dimethyldecane, 1,12-diaminooctadecane,
2,2-bis [4- (4-aminophenoxy) phenyl] propane, 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 ) ₂ (CH ₂ ) ₃ NH
₂ , etc.

An appropriate solvent can be used for the polymerization reaction of the above tetracarboxylic dianhydride and diamine, but a polar solvent is preferably used in view of solubility and the like. By the way, examples of the polar solvent include N, N-
Dialkylamides are useful, such as N, N-dimethylformamide, N, N, which are of low molecular weight.
-Examples include dimethylacetamide. These can be easily removed from the polyamic acid and polyamic acid moldings by evaporation, displacement or diffusion. In addition, as organic polar solvents other than the above, N, N-diethylformamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, dimethylsulfoxide, hexamethylphosphortriamide, N-methyl-2-pyrrolidone, pyridine , Dimethyl sulfoxide, tetramethylene sulfone, dimethyl tetramethylene sulfone and the like. These may be used alone or in combination. Furthermore, the organic polar solvent cresol, phenol, phenols such as xylenol,
Benzonitrile, dioxane, butyrolactone, xylene, cyclohexane, hexane, benzene, toluene and the like may be used alone or in combination. In addition,
Polyamic acid is preferably hydrolyzed in the presence of water, so that the polyamic acid is hydrolyzed to have a low molecular weight.

A polyamic acid is obtained by reacting the above-mentioned tetracarboxylic dianhydride (a) and diamine (b) in an organic polar solvent. The monomer concentration (concentration of (a) + (b) in the solvent) at that time is set according to various conditions, but is preferably 5 to 30% by weight.
The reaction temperature is preferably set to 80 ° C. or lower, particularly preferably 5 to 50 ° C., and the reaction time is about 0.5 to 10 hours.

Thus, the polyamic acid is produced by reacting the acid dianhydride component and the diamine component in the organic polar solvent, and the solution viscosity increases with the progress of the reaction. In the present invention, this phenomenon is utilized to obtain a polyamic acid solution containing a conductive filler in a B-type viscometer of 25
The viscosity at ° C can be adjusted. Further, adjustment by the monomer concentration is also possible.

In the present invention, the viscosity of the polyamic acid solution containing the conductive filler forming the outer layer at 25 ° C. in a B type viscometer is preferably adjusted to 0.01 to 1 Pa · s before use. Further, in the B-type viscometer of the polyamic acid solution containing the conductive filler forming the inner layer, 2
The viscosity at 5 ° C. is preferably adjusted to 1 to 1000 Pa · s before use.

When the viscosity of the polyamic acid solution forming the outer layer is high, it is difficult to form a layer having a different content of the conductive filler only on the surface. On the other hand, when the viscosity of the polyamic acid is low, the inner layer has a conductive filler. Due to the difference in specific gravity, the conductive filler tends to be unevenly distributed in the thickness direction during rotational centrifugal molding, and the variation in the surface resistivity tends to increase. Further, if the solution viscosity is too high, defoaming becomes difficult and the appearance tends to be impaired due to poor film formation.

Examples of the conductive filler include carbon black such as Ketchin black and acetylene black, metals such as aluminum and nickel, metal oxide compounds such as tin oxide and conductive or semi-conductive powders such as potassium titanate, or One or more suitable materials such as conductive polymers such as polyaniline and polyacetylene can be used, and the kind is not particularly limited.

With respect to the average particle diameter of the conductive filler to be used, one having a small particle diameter can be preferably used in view of controlling variations in electric characteristics due to uneven distribution. From this point, in general, those having an average particle diameter based on primary particles of 5 μm or less, especially 3 μm or less, particularly 0.01 μm to 1 μm can be preferably used.

In the present invention, the content of the conductive filler in the polyamic acid solution for forming the outer layer is adjusted so that the content of the conductive filler in the polyamic acid solution for forming the inner layer is different. At that time, the content of any of the layers may be higher. However, when the conductivity of the outer surface is particularly enhanced, the content of the outer layer is higher than that of the inner layer.

The specific amount of the conductive filler to be used can be appropriately determined according to the type, particle size, dispersibility, etc., from the standpoint of attaining the above-mentioned electric characteristics. Generally, in order to prevent deterioration of mechanical properties such as strength in the polyimide resin film, the polyimide resin (solid content) 10
An amount of 30 parts by weight, particularly 3 to 15 parts by weight, is preferable per 0 part by weight.

From the standpoint of maintaining mechanical properties such as the strength described above, the smaller the amount of the conductive filler used, the more preferable. The carbon black such as Ketchin black is used because the electrical properties described above are achieved with the small amount. And the like can be preferably used. In this case, less than 5 parts by weight, especially 1 to 100 parts by weight of the polyimide resin (solid content)
Even with the use amount of 4 parts by weight, the above-mentioned electric characteristics can be achieved.

The conductive filler is blended in the polyimide resin film by, for example, preparing the above-mentioned polyamic acid by adding a conductive filler to the solution using a suitable dispersing machine such as a planetary mixer, a bead mill or a three-roll mill. Can be mixed and dispersed, blended, and then subjected to an appropriate method such as a method of subjecting it to film formation.

When a conductive filler is mixed to prepare the above-mentioned polyamic acid solution, the solvent is first dispersed in an appropriate method such as a ball mill or ultrasonic waves in order to prevent the dispersion of electric characteristics due to uniform dispersion. A method in which a conductive filler is dispersed and then tetracarboxylic dianhydride or its derivative and a diamine are dissolved in the dispersion to be subjected to a polymerization treatment can be preferably applied.

In the present invention, silicone-based or fluorine-based organic compounds that can be blended with the semiconductive belt made of a polyimide resin, additives such as coupling agents,
It can be appropriately added within a range that does not impair the effects of the present invention.

The semiconducting belt of the present invention is a seamless semiconducting belt made of the above-mentioned materials, and has a thickness in which the concentration of the conductive filler on the outer surface portion is discontinuously different from the other portions. It has a region of 1 to 10 μm and is characterized in that the difference in surface resistivity between the outer surface and the inner surface based on the common logarithm is 1.5 or more. However, in order to obtain the above-described effects of the present invention, the thickness of the above region (outer layer) is 1
˜5 μm is preferred.

The surface resistivity of the outer surface is a value based on a common logarithm (logR: R is in units of Ω / □), preferably 1 to 16, and more preferably 5 to 16. Further, the surface resistivity of the inner surface is a value based on the common logarithm and is 1.5 or more than the value of the outer surface,
Preferably, the difference is 2.0 or more.

The total thickness of the semiconductive belt of the present invention is
Although it can be appropriately determined depending on the purpose of use, it is generally 5 to 500 in view of mechanical properties such as strength and flexibility.
The thickness is preferably 10 to 300 μm, especially 20 to 200 μm.

The semiconductive belt can be formed by molding the polyimide film having the above-mentioned electrical characteristics into a desired belt shape. In that case, a polyimide film composed of three or more layers of the same or different layers can be used. The belt having a seamless structure has the advantage that the thickness does not change due to superposition, an arbitrary portion can be set as the belt rotation start position, and the rotation start position control mechanism can be omitted.

On the other hand, in the production method of the present invention, a semiconductive belt having a seamless structure is obtained by performing rotational centrifugal molding and imide conversion using a raw material liquid of a polyimide resin containing a conductive filler.

A method for producing a semi-conductive belt having a seamless structure by rotational centrifugal molding and imide conversion using a raw material liquid of a polyimide resin is known, and for example, the above-mentioned polyamic acid solution is applied to various inner surfaces of a mold. It is developed into a ring shape by a coating method, etc., and while maintaining a uniform thickness by rotary centrifugation, the developed layer is dried and formed into a belt shape, and the formed product is heat-treated to convert the polyamic acid into an imide. Then, it can be carried out by an appropriate method according to the conventional method such as a method of recovering from the mold (JP-A 61-95361, JP-A 64-22514, JP-A 3-180309, etc.). . When forming the seamless belt, appropriate processing such as mold releasing treatment and defoaming treatment can be performed.

According to the present invention, in such a manufacturing method, a conductive filler is contained in advance and it is measured by a B-type viscometer.
1-10 μm thickness solidified on the inner peripheral surface of the molding die using a polyamic acid solution having a solution viscosity of 0.01 to 1 Pa · s at 5 ° C.
After forming the outer layer of m, the content of the conductive filler is different and the solution viscosity at 25 ° C. by the B-type viscometer is 1 to 1000 P.
It is characterized in that the inner layer is molded by rotary centrifugal molding using the polyamic acid solution of a · s. At this time, the inner layer can be formed in the same manner as a conventionally known method, but since the outer layer is thin, it is preferable to perform spray coating or the like when applying the polyamic acid solution. Further, it is preferable to make the thickness uniform after spray coating, and in that case, it is preferable to spray-coat the inner peripheral surface of the molding die with a polyamic acid solution and dry and solidify while rotating the molding die. Further, the mold may be rotated during spray application.

The degree of drying and solidification may be such that the surface of the outer layer is not deformed by the application of the polyamic acid solution for forming the inner layer, but it is preferably dried to less than 6% by weight as the residual ratio of the solvent. . The outer layer may be heat-treated until partial imide conversion occurs.

Thereafter, the polyamic acid solution for forming the inner layer is applied to the outer layer, and the mixture is subjected to rotational centrifugal molding, followed by imide conversion. The imide conversion is preferably carried out in both layers at the same time under conventionally known conditions such as 370 to 370.
Heat treatment is performed at 390 ° C. for 0.5 to 2 hours. At that time, in order to improve the dimensional accuracy of the belt, even after the precursor belt is released from the mold, the precursor belt is externally fitted to another inner mold having a slightly smaller outer diameter than its inner diameter, and then imide conversion is performed. Good.

The semiconductive belt of the present invention can be used in various applications according to the conventional semiconductive belt. In particular, due to its excellent mechanical properties and electrical properties, it can be preferably used as a belt for intermediate transfer of an image in an electrophotographic recording device, a belt for transporting a printing sheet that also serves as the intermediate transfer. In that case, as the recording agent for forming an image on the print sheet, an appropriate agent that can be attached via static electricity can be used.

[0042]

EXAMPLES Examples and the like specifically showing the constitution and effects of the present invention will be described below.

Example 1 Vulcan XC (manufactured by Cabot Co., particle size 0. 6) in 1674 g of N-methyl-2-pyrrolidone (NMP).
16.1 g (4% by weight with respect to the polyimide solid content) of 3 μm and a specific gravity of 1.8 g / cm ³ ) were mixed for 6 hours (room temperature) with a ball mill. 294.2 g of 4,4′-benzophenonetetracarboxylic dianhydride (BPDA) and 108.2 g of p-phenylenediamine (PDA) were dissolved in this NMP, and the mixture was reacted in a nitrogen atmosphere at room temperature for 3 hours with stirring. Thus, an inner layer polyamic acid solution having a pressure of 300 Pa · s was obtained.

On the other hand, Vulcan XC dried in 16740 g of N-methyl-2-pyrrolidone (NMP) (manufactured by Cabot Co., particle size 0.3 μm, specific gravity 1.8 g / cm ³ ).
24.16 g (6% by weight with respect to the polyimide solid content) was mixed with a ball mill for 6 hours (room temperature). BP to this NMP
DA294.2g and PDA108.2g were melt | dissolved, it was made to react, stirring in nitrogen atmosphere for 4 hours at room temperature, and the polyamic-acid solution for outer layers of 0.15 Pa.s was obtained.

The above polyamic acid solution for outer layer was sprayed onto the inner surface of a molding die having an inner diameter of 330 mm and a length of 500 mm to a thickness of 3 μm and then rotated at 1500 rpm for 10 minutes to obtain a uniform coated surface. Next, while rotating at 250 rpm, hot air of 60 ° C. was applied from the outside of the mold for 30 minutes (at that time, the thickness was 1 μm), and then a polyamic acid solution for the inner layer was applied to a thickness of 400 μm with a dispenser, and then 1
It was rotated at 500 rpm for 10 minutes to obtain a uniform coated surface.
Next, while rotating at 250 rpm, hot air of 60 ° C. is applied from the outside of the mold for 30 minutes, heated at 150 ° C. for 60 minutes, and then heated to 300 ° C. at a temperature increase rate of 2 ° C./min. The mixture was heated at 300 ° C. for 30 minutes to remove the solvent, remove the dehydrated ring-closing water, and convert the imide. Then, the temperature was returned to room temperature, and the mold was peeled off to obtain a seamless semiconductive belt of 73 to 78 μm. When the cross section of this belt was observed with a scanning electron microscope, a region (outer layer: thickness 0.7 μm) in which the concentration of the conductive filler was discontinuously different from the other part was observed.

Example 2 In Example 1, as the polyamic acid solution for the outer layer, 1
Vulcan XC dried by 6740 g of N-methyl-2-pyrrolidone (NMP) (manufactured by Cabot Co., particle size 0.
3 μm, specific gravity 1.8 g / cm ³ ) 4.03 g (1% by weight relative to polyimide solid content) were mixed in a ball mill for 6 hours (room temperature), and this NMP was mixed with BPDA 294.2 g and PD.
0.15P obtained by dissolving 108.2 g of A and reacting in a nitrogen atmosphere at room temperature for 4 hours with stirring.
The same operation as in Example 1 was carried out except that the polyamic acid solution of a · s was used to obtain a seamless semiconductive belt having a thickness of 72 to 78 μm. When the cross section of this belt was observed with a scanning electron microscope, a region (outer layer: thickness 0.8 μm) in which the concentration of the conductive filler was discontinuously different from the other part was observed.

Comparative Example 1 A seamless semiconductive belt having a thickness of 72 to 78 μm was obtained by performing the same operation as in Example 1 except that the step of forming the outer layer using the polyamic acid solution for the outer layer was omitted. Obtained.

Comparative Example 2 In Example 1, the viscosity of the polyamic acid solution for the outer layer was adjusted to 10
The same operation as in Example 1 was carried out except that the pressure was changed to 0 Pa · s, but the outermost layer could not be formed, and a seamless semiconductive belt could not be obtained.

The following characteristics of the semiconductive belts obtained in the above Examples and Comparative Examples were examined.

(Surface resistivity) Hiresta IP, MCP-
HT260 (manufactured by Mitsubishi Petrochemical, probe: HR-100)
Applied voltage 100V, after 1 minute, measurement conditions 25 ° C, 60
The surface resistivity at% RH was investigated. The measurement was performed on the outer surface and the inner surface (n = 10), and the difference between them was also obtained.

(Volume Resistivity) Hiresta IP, MCP-
HT260 (manufactured by Mitsubishi Petrochemical, probe: HR-100)
Applied voltage 100V, after 1 minute, measurement conditions 25 ° C, 60
The volume resistivity at% RH was investigated.

(Image Transferability and Paper Separation) The semiconductive belts obtained in Examples and Comparative Examples were incorporated into a commercially available copying machine as a recording sheet conveying belt which also serves as an intermediate transfer. Good when a clear and accurate image is obtained by good transfer, and when no paper separation failure occurs.
The case where the transfer failure, the unclear surface image, the inaccurate surface image were obtained, and the case where the paper separation failure occurred were regarded as failures.

The results are shown in Table 1.

[0054]

[Table 1] As shown in the results of Table 1, in the semiconductive belts of the examples, the surface resistivity of the outer surface can be easily adjusted while maintaining the overall volume resistivity, and a problem due to residual stress occurs. It becomes difficult.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B29K 105: 16 B29K 105: 16 B29L 29:00 B29L 29:00 F term (reference) 2H200 FA13 FA18 JB07 JB45 JB46 JB47 JC04 JC15 JC16 JC17 LC03 LC04 MA04 MA11 MA12 MA13 MA14 MA17 MA20 MB02 MB04 MB05 MC10 MC15 4F100 AK49A AK49B BA02 BA26 CA21A CA21B EH612 EH812 GB41 JA06A JA06B J010102A01 AR01 AG02 A0140A02

Claims (3)

[Claims] 1. A semi-conductive belt having a seamless structure made of a polyimide resin containing a conductive filler, wherein a concentration of the conductive filler on an outer surface portion is discontinuously different from other portions and has a thickness of 1 to 10 μm. With a region, the difference in surface resistivity between the outer surface and the inner surface based on the common logarithm is 1.
A semi-conductive belt characterized by being 5 or more. 2. A method for producing a semi-conductive belt, wherein a semi-conductive belt having a seamless structure is obtained by performing rotational centrifugal molding and imide conversion using a raw material liquid of a polyimide resin containing a conductive filler. 25 ℃ by B type viscometer containing conductive filler
After forming a solidified outer layer having a thickness of 1 to 10 μm on the inner peripheral surface of the mold using a polyamic acid solution having a solution viscosity of 0.01 to 1 Pa · s, the content ratio of the conductive filler is different.
Solution viscosity at 25 ° C measured by a viscometer is 1-1000 Pa
A method for producing a semiconductive belt, which comprises forming the inner layer by rotational centrifugal molding using the polyamic acid solution of s. 3. The semi-conductive belt according to claim 2, wherein, when the outer layer is formed, the polyamic acid solution is spray-coated on the inner peripheral surface of the mold and dried and solidified while rotating the mold. Manufacturing method.