JP2003094463A - Seamless tubular article, its manufacturing method, and image forming apparatus using obtained seamless tubular article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seamless tubular article in which the rear surface of the article made of a heat resistant resin composition is made in a low friction and which has a high accuracy and a method for inexpensively manufacturing the seamless tubular article having a high product yield and to provide an image forming apparatus using the obtained seamless tubular article. SOLUTION: The method for manufacturing the seamless tubular article made of the heat resistant resin composition comprises a coating step of coating the surface of a core made of a metal covered with a coating layer made of inorganic particles and a resin component with the liquid-like heat resistant resin composition, a solidifying step of solidifying or curing the liquid-like heat resistant resin composition coating on the surface of the core, and a separating step of separating the solidified or cured heat resistant resin composition together with the inorganic particles in the coating layer from the core. The seamless tubular article is obtained by the method. The image forming apparatus uses the seamless tubular article.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seamless tubular article (seamless belt or seamless film) preferably used for a photoreceptor, a transfer belt, a fixing belt, etc. in an electrophotographic apparatus such as a copying machine and a printer, and a method for producing the same. And an image forming apparatus.

[0002]

2. Description of the Related Art In an electrophotographic apparatus, a rotating member made of metal, various plastics or rubber is used as a photosensitive member, a transfer belt or a fixing belt. In order to reduce the size and improve the performance of the device, it may be preferable that these rotating bodies be deformable to some extent. In that case, a tubular member made of a thin plastic film is used. At that time, if there is a seam in the tubular object, a defect due to the seam occurs in the output image. Therefore, it is necessary to use a seamless tubular object (seamless tubular object).

Regarding a method for producing a seamless tubular article, for example, JP-A-60-170862 discloses a method of forming a film on the inner peripheral surface of a mold by a rotational molding method, and JP-A-6-202513 discloses. A method of melting and extruding a resin into a ring to form a film, and JP-A-6-222695 discloses a method of applying a resin solution to the outer surface of a cylindrical mold by dipping to a constant thickness, and then pulling out the mold after heating and forming a film. Have been described.

Examples of the resin material for forming this seamless tubular material include polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyphenylene sulfide, and the like. Among these, strength, heat resistance, and dimensional stability. A polyimide resin is particularly preferable from the viewpoint of the property.

In the meantime, in order to manufacture a seamless tubular product made of a polyimide resin, there is a problem that extrusion molding, inflation or vacuum molding cannot be performed like a tubular product made of a thermoplastic resin. Therefore, as a method for producing a seamless tubular product made of polyimide, there is no choice but to adopt a method in which the precursor polyamic acid solution is applied to a mold or the like, and is imidated by heating to remove the mold.

[0006] On the other hand, in these methods for producing a seamless tubular article, a metal such as aluminum or stainless steel is generally used as the material of the die. However, the polyimide resin is a resin used as an adhesive, and when a polyamic acid solution is applied to a mold or the like and the imide is converted by heating, the polyimide tubular material shrinks and adheres or adheres to the mold, Due to the binding force, it is difficult to remove the polyimide tubing from the mold.

When the polyimide precursor solution is applied to the surface of the mold (core) and heated to convert the imide to obtain a seamless tubular product, the seamless tubular product is smoothly separated from the mold. Therefore, a method of coating the surface of the mold with a mold-releasing resin to reduce the adhesive energy on the surface is considered. However, lowering the adhesive energy on the surface of the core causes many problems such as cissing and flow that occur when the liquid polyimide precursor is applied to the surface of the core.

With respect to the above problems, Japanese Patent Laid-Open No. 10-159
In the '68 publication, a porous ceramic cylindrical core is used as a core to form a polyimide tubular body, and then a liquid is exuded from pores from the inside to the outside of the cylindrical core by the exuded liquid, A method has been proposed in which the adhesive force between the outer surface of the core body and the polyimide tubular material is weakened and then the polyimide tubular material is separated. However, this method has a problem that the manufacturing process is complicated.

Further, in Japanese Patent Application Laid-Open No. 3-261518,
As a method of improving the cissing phenomenon and flow phenomenon of the polyimide precursor solution and smoothly separating the tubular body and the core body, a method of providing a hydrophilic coating film such as polyvinyl alcohol on the release layer is proposed. Has been done. However, in the method of using the core body coated with the release resin, to form a thin coating film having hydrophilicity on the outer surface thereof, and further coating a polyimide precursor solution on the hydrophilic film to obtain a tubular article, The polyimide precursor solution, which is a thermosetting resin, needs to be completely converted into an imide, and a temperature of 250 to 450 ° C. is necessary.

Further, in the production of a seamless tubular article made of a polyimide resin, for example, as disclosed in JP-A-10-1000171 and JP-A-10-296761, a polyimide precursor is formed on the inner surface of a cylindrical body. A centrifugal molding method in which the solution is developed and dried while rotating. JP-A-1-
The inner surface coating method disclosed in Japanese Patent No. 139228 is mentioned. However, all of these methods require a temperature of 250 to 450 ° C. in order to completely convert the polyimide precursor solution, which is a thermosetting resin, into an imide.

In the production of a seamless tubular product made of a polyimide resin, which requires the complete imide conversion of the polyimide precursor solution, as described above, 250 to 450.
A temperature of ℃ is required, but there is no mold release agent or mold release resin that can withstand these high temperatures, and therefore, the polyimide precursor solution is applied to the surface of the core body coated with the mold release resin as the first step. After the imidization proceeds at 100 to 200 ° C. to form an intermediate, the intermediate is separated from the core, and as a second step, the tubular body is again inserted into the metal-only core to obtain 250 to 45.
It was necessary to complete the imidization at 0 ° C. That is,
The manufacturing method is not only complicated in the manufacturing process,
Since the tubular object is taken out at the intermediate stage of imidization and attached to another metal core body, foreign matter such as dust is caught between the polyimide film and the core body at the time of remounting. This also causes a problem that the yield is reduced.

Further, in Japanese Patent Laid-Open No. 1-156017,
In order to obtain a tubular product with a uniform thickness, the polyimide acid solution is poured onto the inner surface of a molded tube such as a glass tube or a stainless steel tube having a smooth inner surface, and then the molded tube is held vertically, A method has been proposed in which a running body such as a bullet-shaped body or a spherical body is dropped by its own weight to form a certain thickness, and then dried and imidized by heating to form a tubular body, and then extracted from a molded pipe. However, with the above-mentioned method, it is very difficult to remove the polyimide tubular material from the inner surface of the molded tube such as a glass tube or a stainless tube. In addition, since the polyimide tubular product is taken out from the inside of the molded tube, it is difficult to produce a tubular product having a small inner diameter, and it is also very difficult to produce a long product.

Therefore, Japanese Patent Application Laid-Open No. 7-76025 proposes a method of forming an inorganic coating layer made of an inorganic compound on the surface of a metal core. But,
The method of coating the surface of the metal core body with a heat-resistant material such as an inorganic coating layer is not sufficient in releasing performance of the inorganic coating layer, and in addition, heating at 250 ° C. or higher is required in the ceramicizing step after coating. Since it was necessary, workability was poor, and the adhesive strength between the surface of the metal core and the inorganic coating layer was not sufficient.

Furthermore, since there is a difference in the coefficient of thermal expansion between the surface of the metal core and the inorganic coating layer, there is a problem that the inorganic coating layer is cracked when heating and cooling are repeated. (For example, the coefficient of linear expansion of stainless steel used as a metal core: 1.15 × 10 ⁻⁵ ° C., the coefficient of linear expansion of SiO ₂ used as an inorganic coating layer is 7 to 8 × 10 ⁻⁶ ° C. And small).

Generally, a polyimide resin is formed by applying a solution in which a polyimide precursor is dissolved, drying the solvent, and then heating and curing. As the solvent at this time, an aprotic polar solvent is used, but each of the aprotic polar solvents has a high boiling point and very slow drying. Furthermore, since the polyimide resin is a resin having low gas permeability, a heating step for heating and forming a polyimide resin film (solvent drying of the polyimide precursor solution and imide conversion reaction)
Therefore, it is necessary to allow the generated gas to easily escape from the inside of the resin film. Therefore, the surface roughness Rz
Of 0.5 μm or more is used. But,
As a countermeasure against the cracks, an inorganic coating layer of 1μ
There is a problem that a thin layer having a thickness of m or less cannot be applied uniformly.

A typical example of the use of a seamless tubular product made of a polyimide resin is a belt or a conveyor belt for rotation transmission in a weak electric acoustic device or other machine, or a heat fixing device such as a copying machine or a laser beam printer. A fixing belt or the like may be used. Here, a seamless tubular product made of a polyimide resin, which is used as a fixing belt for heat fixing of a copying machine or a laser beam printer, will be described as an example. In electrophotographic copying machines or laser beam printers, a heat roller method is generally used as a fixing device for fixing a toner image formed on a copying machine or transfer paper. That is, the toner image is fixed by sequentially feeding the transfer paper on which the toner image is formed between the fixing roller having a heating mechanism and the pressure roller that is in pressure contact with the heating roller to heat and melt the toner.

In recent years, technical development of this fixing device has progressed, and use of a polyimide seamless tubular article is being considered in place of the above-mentioned heat fixing roller. An example of a fixing device using the polyimide seamless tubular article is shown in FIG. Figure 6
FIG. 3 is a schematic view of a fixing device using a polyimide seamless tubular article. The fixing device includes a polyimide seamless tubular article 61, a nip pad 62 made of silicone rubber inside the polyimide seamless tubular article 61, a nip head 63 for locally increasing the nip pressure, and a heat roll 65.
And supports the nip pad 62 and the nip head 63,
And a support 64 for forming a constant nip pressure. The fixing device is a mechanism that supplies the transfer paper on which the unfixed toner image is formed between the heat roll 65 and the polyimide seamless tubular material 61 and sequentially fixes the toner images.

The characteristics required for the seamless tubular article used for the fixing device are that the back surface (inner peripheral surface) of the seamless tubular article rotates in contact with the nip pad 62, so that the material must have a low friction coefficient. If the coefficient of friction on the back surface is large, problems such as wrinkling of the tubular object may occur during rotation. In addition, since the mechanism that instantly fuses the toner image on the transfer paper passing through the outer surface of the polyimide tubular object, if the thickness of the polyimide tubular object varies, the toner cannot be melted uniformly, and the offset phenomenon occurs. Occurs. Therefore, it is necessary to minimize the variation in the thickness of the tubular object.

However, it is practically difficult to apply the low friction material to the back surface of the polyimide tubular material, and as described above, when the polyamic acid solution is applied to the mold and the imide is converted by heating, the polyimide tubular material becomes It contracts and adheres or adheres to the mold, and the binding force makes it difficult to remove the polyimide tubular product from the mold, so that the product yield is high and stable manufacturing cannot be performed. The above problems also occur with other heat-resistant resin compositions having the same properties as polyimide.

[0020]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems and forms a film of a low friction material on the back surface of a seamless tubular article made of a heat-resistant resin composition such as polyimide to form a seamless tubular article. To provide a highly accurate seamless tubular article having a low friction on the back surface of the article, a method for producing a seamless tubular article having a high product yield and low cost, and an image forming apparatus using the obtained seamless tubular article. With the goal.

[0021]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, found that the above-mentioned problems can be achieved by the following invention, and completed the invention. It was That is, the present invention is

<1> A method for producing a seamless tubular article made of a heat-resistant resin composition, comprising a liquid heat-resistant resin composition on a surface of a metal core covered with a coating layer made of inorganic particles and a resin component. A coating step of coating an object, a solidification step of solidifying or curing a liquid heat-resistant resin composition applied to the surface of the metal core, and a coating of the solidified or cured heat-resistant resin composition A method for producing a seamless tubular product, comprising: a step of separating the inorganic particles in the layer from the metal core body.

<2> The coating step is a step of coating the polyimide precursor solution as the liquid heat-resistant resin composition to a uniform thickness on the surface of the metal core covered with the coating layer. The solidification step is a step of heating the applied polyimide precursor solution to cause an imide conversion reaction, which is a method for producing a seamless tubular article according to <1>.

<3> The method for producing a seamless tubular product made of the heat resistant resin composition according to <2>, wherein a conductive agent is dispersed in the polyimide precursor solution. <4> The coating layer is made of a resin composition to which an inorganic compound is added. <1> to <3>
The method for producing a seamless tubular article according to any one of 1.

<5> In the coating step, the metal core body is rotated and moved in the axial direction of the metal core body covered with the coating layer at a constant speed while a certain amount of liquid heat resistance is maintained. The method for producing a seamless tubular article according to any one of <1> to <4>, which is a step of applying the resin composition to the surface of the metal core body. <6> A seamless tubular article produced by the method for producing a seamless tubular article according to any one of <1> to <5>.

<7> The seamless tubular article according to <6>, wherein the relationship between the friction coefficient μ1 on the front surface and the friction coefficient μ2 on the back surface is μ1> μ2. <8> Friction coefficient μ2 of the back surface of the seamless tubular article
Is less than or equal to 0.3 <6> or <7
The seamless tubular article described in

<9> An image forming apparatus using the seamless tubular article according to any one of <6> to <8>. <10> An image forming apparatus including a belt fixing type fixing device, wherein the fixing belt of the fixing device is <6>.
<8> The image forming apparatus according to <9>, wherein the seamless tubular article according to any one of <8> to <8> is used.

According to the method for producing a seamless tubular article of the present invention, a metallic core body covered with a coating layer composed of inorganic particles and a resin component (hereinafter sometimes referred to as "inorganic coating layer") is provided. On the surface, a liquid heat-resistant resin composition such as a polyimide precursor solution is applied to a uniform thickness, and after heating to solidify or cure the imide conversion reaction or the like, the seamless tubular product is separated from the metal core. By doing so, the manufacturing process can be one step, further, the friction coefficient of the back surface of the seamless tubular product is smaller than the friction coefficient of the surface of the seamless tubular product, and moreover, the heat-resistant resin such as polyimide having high accuracy is the main component. A seamless tubular product can be obtained with a high product yield and at low cost.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a seamless tubular article of the present invention comprises a coating step of coating a liquid heat resistant resin composition on the surface of a metal core covered with an inorganic coating layer, A solidification step of solidifying or curing a liquid heat-resistant resin composition applied to the surface of the core body, and the solidified or cured heat-resistant resin composition, together with the inorganic particles in the coating layer, the metal And a separation step of separating from the core body.

The method for producing a seamless tubular article made of the heat-resistant resin composition of the present invention will be described below by taking polyimide, which is a typical heat-resistant resin composition, as an example. The method for producing a seamless tubular product containing polyimide as a main component (hereinafter, simply referred to as “polyimide seamless tubular product”) can be applied to a heat resistant resin composition having the same properties as polyimide. . Specifically, instead of the polyimide precursor solution, a liquid heat-resistant resin composition other than polyimide is applied to the surface of the metal core covered with the coating layer, and the liquid heat-resistant resin composition is applied. A solid tubular product made of a heat-resistant resin composition other than polyimide can be obtained by a method of solidifying or curing the resin and separating it from the metal core.

The method for producing the seamless tubular article of the present invention comprises:
Start with the coating process. First, the coating process in the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a metal core body having an inorganic coating layer and a coating layer of a polyimide precursor formed on the surface. In FIG. 1, reference numeral 11 denotes a metal core body. The surface of the metal core body 11 is covered with an inorganic coating layer 12, and a coating layer 13 is formed from the polyimide precursor solution. The coating step in the present invention refers to a step of applying a polyimide precursor solution to the surface of the metal core 11 covered with the inorganic coating layer 12 to obtain a coating layer.

<Inorganic Coating Layer> The inorganic coating layer covering the surface of the metal core is composed of inorganic particles having excellent heat resistance and a resin component fixing the inorganic particles. The resin component decomposes at a high temperature in the heating imide conversion reaction step, and a thin layer of only inorganic particles is uniformly formed on the back surface of the seamless tubular article belt. Further, by providing the inorganic coating layer, even in the coating step of molding the polyimide precursor solution into a liquid form on its surface, cissing phenomenon of the polyimide precursor solution and flow phenomenon do not occur, so coating in solution form Starting from the process, the seamless tubular product can be manufactured in one process while being held in the core until a finished product is obtained.

Further, since the surface of the metal core is covered with the inorganic coating layer having a uniform thickness, the seamless tubular article of the final product does not have any appearance defect such as convexity. Further, since the inorganic coating layer contains a resin component, thermal expansion of the metal core in the heating step (including solvent drying of the polyimide precursor solution and imide conversion reaction) and subsequent cooling It is possible to prevent the occurrence of cracks or the like in the inorganic coating layer due to the shrinkage of the metal core body in 1.

Further, the inorganic coating layer can form a uniform thin film on the surface of the metal core, and can be baked at a low temperature. As a result, it is possible to manufacture a highly accurate polyimide seamless tubular product with a high product yield, low cost, and a small coefficient of friction on the back surface of the belt.

(Inorganic Particles) The inorganic particles which are a constituent component of the inorganic coating layer in the present invention are not particularly limited, but are preferably inorganic compounds having a number average particle diameter of 0.1 to 50 μm, and the number average is Particle size is 0.2-3
More preferably, the number average particle size is 0.
It is more preferably 5 to 10 μm. When the number average particle diameter is 0.1 to 50 μm, the lubricity of the inorganic particles is high, which is preferable. Examples of the inorganic particles include boron nitride, graphite, mica and talc, and among these, boron nitride and graphite are preferable. Specific examples of the preferable inorganic particles include Aerodag G (manufactured by Nippon Acheson Co., Ltd.) in which graphite is dispersed in a resin component, and Whity Coat (Co., Ltd.) in which boron nitride is dispersed in a resin component.
Odek) can be mentioned.

(Resin Component) The resin component which is a constituent component of the inorganic coating layer according to the present invention is not particularly limited, and examples thereof include ethyl cellulose, EVA resin, polystyrene resin and polyethylene resin. Among them, ethyl cellulose and EVA resin are preferable. preferable.

(Thickness of Inorganic Coating Layer) The thickness of the inorganic coating layer is preferably 0.1 μm to 10 μm, more preferably 0.5 μm to 4 μm, and 1 μm to 3 μm. Is more preferable. When the thickness is less than 0.1 μm, the uniformity of the thickness of the film cannot be obtained, and thus coating unevenness may occur. When the thickness exceeds 10 μm, the coating film may be dripping or the like. There may occur a problem that the thickness is not uniform.

(Surface Roughness) Since the surface roughness of the inorganic coating layer is transferred to the back surface of the seamless tubular product of the final product, it can be adapted to the purpose of use of the seamless tubular product. The surface roughness of the inorganic coating layer applied to the metal core is an arithmetic average roughness Ra of 0.
5 to 1.5 μm is preferable, 0.6 to 1.2 μm is more preferable, and 0.7 to 1.1 μm is further preferable. If the surface roughness Ra is more than 1.5 μm, the surface roughness of the polyimide seamless tubular article may become rough, and the surface roughness required as the surface layer of the fixing device described later may not be obtained. On the other hand, when the surface roughness Ra is less than 0.5 μm, the generated gas component may accumulate inside the polyimide resin film, and the film of the seamless tubular product may be formed in a convex shape.

In addition, the inorganic coating layer in the present invention provides a seamless tubular product having a high shape accuracy,
It is preferably composed of a resin composition to which an inorganic compound is added.

<Polyimide Precursor Solution> Examples of the polyimide precursor solution usable in the present invention include those obtained by reacting an aromatic tetracarboxylic acid component and an aromatic diamine component in an organic polar solvent. Examples of the aromatic tetracarboxylic acid component include pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5,6.
-Biphenyltetracarboxylic acid, 2,2 ', 3,3'-
Biphenyltetracarboxylic acid, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 3,3', 4,4'-diphenylethertetracarboxylic acid, 3,3 ', 4,4'
-Benzophenone tetracarboxylic acid, 3,3 ', 4,
4'-diphenylsulfone tetracarboxylic acid, 3,
3 ', 4,4'-azobenzenetetracarboxylic acid, bis (2,3-dicarboxyphenyl) methane, bis (3,3
4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-
Examples thereof include bis (3,4-dicarboxyphenyl) hexafluoropropane, and a mixture of these tetracarboxylic acids may be used.

The aromatic diamine component is not particularly limited, and is m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylyl. Diamine, p-xylylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6
-Diaminonaphthalene, 2,4'-diaminonaphthalebiphenyl, benzidine, 3,3-dimethylbenzidine,
3,3'-dimethoxybenzidine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (oxy-p, p'-dianiline; ODA),
4,4'-diaminodiphenyl sulfide, 3,3'-
Diaminobenzophenone, 4,4'-diaminophenyl sulfone, 4,4'-diaminoazobenzene, 4,4 '
-Diaminodiphenylmethane, β, β-bis (4-aminephenyl) propane and the like.

Examples of the organic polar solvent include N-
Methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphortriamide and the like can be mentioned. These organic polar solvents may be mixed with phenols such as cresol, phenol and xylenol, and hydrocarbons such as hexane, benzene and toluene, if necessary. The polar solvent may be used alone or as a mixture of two or more kinds.

(Conducting Agent of Polyimide Precursor Solution) The polyimide seamless tubular article as the final product may be required to have conductivity depending on the purpose of use, and in that case, a conducting agent is added to the polyimide precursor solution. By doing so, conductivity can be imparted to the final product polyimide seamless tubular article. Examples of the conductive agent include electron conductive conductive agents and ion conductive conductive agents.

Examples of the electron conductive type conductive agent include carbon black, graphite, aluminum, nickel,
Metals or alloys such as copper alloys; metal oxides such as tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide, and tin oxide-antimony oxide composite oxides.
Examples of the ion-conducting conductive agent include sulfonates, ammonia salts, and various surfactants such as cation-based, anion-based, and nonionic-based surfactants.

Further, as a means for imparting conductivity to the final product polyimide seamless tubular material, there is a method of blending a conductive polymer with the polyimide precursor solution. As the conductive polymer, for example, a copolymer of a (meth) acrylate whose carboxyl group binds a quaternary ammonium salt group and another compound (for example, styrene); a maleimide which binds a quaternary ammonium salt group,
Polymers that bind quaternary ammonium salt groups such as copolymers with methacrylates; polymers that bind alkali metal salts of sulfonic acids such as sodium polysulfonate; polyethylene oxide, polyethylene glycol-based polyamide copolymers, polyethylene oxid-epichlorohydrin Copolymers polyether amide imides, polymers having a hydrophilic unit of at least an alkyl oxide bonded in the molecular chain such as block-type polymers having a polyether as a main segment, and the like, and further, an electron-conducting conductive agent Examples thereof include polyaniline, polythiophene, polyacetylene, polypyrrole, and polyphenylene vinylene. These conductive polymers can be used in a dedoped state or a doped state. The above-mentioned resistance value can be stably obtained by using one kind or a combination of two or more kinds of the above-mentioned conductive agent or conductive polymer and the surfactant.

The viscosity of the polyimide precursor solution is 50.
It is preferably in the range of 1000 to 1000 poises, more preferably in the range of 100 to 200 poises. The viscosity of the polyimide precursor solution is 50
It is convenient and preferable for forming a uniform film thickness to be in the range of up to 1000 poise.

(Method of applying the polyimide precursor solution) On the surface of the metal core body covered with the inorganic coating layer,
The method of applying the polyimide precursor solution to a substantially uniform thickness is not particularly limited, but the following application method is to efficiently and reasonably apply the polyimide precursor solution to a substantially uniform thickness. It is preferable in that it can A method for applying such a preferable polyimide precursor solution will be described with reference to the drawings. FIG. 2A is a schematic view showing a method of applying the polyimide precursor solution of the present invention to a metal core body covered with an inorganic coating layer. On the other hand, FIG.
2B is a cross-sectional view of a coated portion of the metal core body covered with the inorganic coating layer shown in FIG. 2A.
In FIG. 2, 21 is a metal core covered with the inorganic coating layer, 22 is a plate, 23 is a container, and 24 is a polyimide precursor solution.

While rotating the metal core 21 in the direction of arrow A at a constant speed, a fixed amount of the polyimide precursor solution is dropped from the container 23 containing the polyimide precursor solution 24 on the surface of the metal core 21. Then, this is applied while smoothing with the plate 22 that is in contact with the surface of the metal core 21, and as a result, the polyimide precursor solution 24 that has been uniformly smoothed is covered with the inorganic coating layer. It is applied to the surface of the metal core body 21. In the present invention, the method of applying the polyimide precursor solution to the metal core covered with the inorganic coating layer is not limited to this method, and other methods such as dip coating may be used.

<Seamless tubular product> The seamless tubular product containing polyimide as a main component of the present invention is a polyimide precursor solution applied to the outer surface of the metal core covered with the above-mentioned inorganic coating layer. It can be manufactured by going through a solidification step of heating to perform an imide conversion reaction, and a separation step of separating the polyimide obtained by the solidification step from the metal core together with the inorganic particles in the inorganic coating layer.

The polyimide seamless tubular article of the present invention will be described below with reference to the drawings. FIG. 3A is a longitudinal sectional view of the polyimide seamless tubular article of the present invention. On the other hand, FIG. 3B is a cross-sectional view taken along the line aa of the polyimide seamless tubular product shown in FIG. In FIG. 3, 3
0 indicates the polyimide seamless tubular article of the present invention. The polyimide seamless tubular article 30 includes a polyimide layer 31 and
Inorganic particle layer 32 coated on its inner surface (back surface)
It consists of and.

(Friction Coefficient of Seamless Tubular Product) On the back surface of the seamless tubular product of the present invention, a thin layer of the above-mentioned inorganic particles is formed as described above, and due to the effect of the inorganic particles, the friction coefficient of the back surface is obtained. It becomes possible to make μ2 smaller than the friction coefficient μ1 of the surface. The friction coefficient μ2 on the back surface is preferably 0.3 or less, and more preferably 0.2 or less. The friction coefficient μ2 of the back surface is 0.
If it exceeds 3, as described above, problems such as wrinkles occurring in the seamless tubular product may occur. on the other hand,
The friction coefficient μ1 of the surface of a general polyimide seamless tubular article is 0.3 to 0.4.

The friction coefficient can be measured using a static-dynamic friction coefficient meter (manufactured by Kyowa Interface Science Co., Ltd.) as shown in FIG. The static friction coefficient meter shown in FIG. 4 is a steel ball (diameter 3 m
m) 43, a zero adjustment balance 44, a load cell 45, and a load (100 g) 46. Specifically, the thickness 10
A seamless tubular object 41 having a thickness of 0 μm is prepared, set on a fixing table 42, and the seamless tubular object 41 is horizontally moved at a moving speed of 0.1 cm / sec under a load of 100 g to measure a friction coefficient. To do.

(Surface Roughness of Surface of Seamless Tubular Material) The surface roughness of the surface of the seamless tubular material has a ten-point average roughness Rz of 0.01 to 10 in terms of toner cleaning property and paper releasability. The thickness is preferably in the range of 10 μm, and 0.
The range of 1 to 5 μm is more preferable.

(Inner Diameter of Seamless Tubular Material) The inner diameter of the seamless tubular material is determined according to the outer diameter of the metal core. The inner diameter of the seamless tubular product is 10 mm to 1
It is preferably in the range of 000 mm, and 15 mm to 6
The range of 00 mm is more preferable. When the inner diameter of the seamless tubular product is in the range of 10 mm to 1000 mm, it is preferable for forming a uniform film thickness.

(Thickness of Seamless Tubular Material) The thickness of the seamless tubular material is preferably in the range of 10 to 100 μm, more preferably in the range of 20 to 80 μm. The thickness of the seamless tubular product is 10 to 100 μm.
The range of m is preferable for forming a uniform film thickness.

<Image Forming Apparatus> An example of an image forming apparatus using the polyimide seamless tubular article of the present invention will be described below with reference to the drawings. FIG. 5 is a schematic view showing an example of a full-color image forming apparatus using the polyimide seamless tubular article of the present invention. The photoconductor (electrostatic latent image carrier) 51 is a-
A photosensitive drum or belt having a photoconductive insulating layer such as Se, OPC (organic photoconductor), a-Si, or ZnO is shown. Of these, OPC and a-Si photoconductors are preferably used. The photoconductor 51 is uniformly charged by the corona charger 52. For charging the photoconductor 51, a contact type charging device using a roller or a magnetic brush may be used in addition to such a non-contact type charging device.

The photoconductor 51 is imagewise exposed by an exposure device (not shown), and an electrostatic latent image is formed on the photoconductor 51. This electrostatic latent image is developed by the developer at a position facing each of the developing devices 55a to 5d. Developing device 55
In the case of a full-color machine, cyan, magenta, yellow, and black developers are introduced in a to 55d. Further, by adding a means for controlling the developing devices 55a to 55d and incorporating a system capable of selecting the developing device for storing the toner of the present invention in accordance with an input from a user or the like, a stereoscopic image can be selectively formed. Good. Developing devices 55a-5
5d may be a magnetic brush developing system or a non-magnetic one-component developing system.

The toner images of the respective colors formed on the photosensitive member 51 are sequentially transferred to the intermediate transfer member 54. Intermediate transfer member 5
4 has a structure in which a pipe-shaped conductive cored bar 54b is included, and an elastic body layer 54a whose electric resistance value is controlled is provided around it. The toner image transferred onto the surface of the intermediate transfer member 54 is transferred onto the surface of the recording medium 60 by applying a bias having a polarity opposite to the frictional charge of the toner by the transfer device 56. After that, the photoconductor 51 returns to the initial state through the cleaning process by the detachable cleaning means 57.

The recording medium 60 on which the toner image is transferred is
The heating roll 65 and the heating roll 65, which is provided with a pressure roll (fixing belt) 61 using the polyimide seamless tubular material of the present invention, has a built-in heating element such as a halogen heater, and is pressed against it with a pressing force. It is fixed on the recording medium by passing through the nip portion between the elastic pressure roller. The polyimide seamless tubular article of the present invention may be used as the following members in addition to the pressure roll (fixing belt) 61. Contact type belt charger Belt type belt type intermediate transfer body Belt type transfer device

The above description has been centered on the seamless tubular product containing polyimide, which is a typical heat-resistant resin composition, as the main component, but the seamless tubular product made of a heat-resistant resin composition other than polyimide has also been described above. What is obtained by the method for producing a seamless tubular article is a seamless tubular article having a friction coefficient on the back surface smaller than the friction coefficient on the surface and having a high degree of accuracy, and the same effect as that of the polyimide seamless tubular article can be obtained.

[0061]

EXAMPLES The present invention will be described in more detail below with reference to examples. (Example 1) As a metal core, arithmetic mean roughness Ra1.
Using an aluminum tube of 7 μm, outer diameter 68 mm, thickness 1 mm,
Aerodac G (a resin composition in which graphite is dispersed) of Nippon Acheson Co., Ltd. is uniformly applied by spraying, dried at room temperature, and a metal core covered with a coating layer composed of inorganic particles and a resin component. Got the body The thickness of the coating layer is 1 μm, and the surface roughness of the metal core body surface after being covered with the coating layer is 1.5 μm in terms of arithmetic average Ra.
Met.

While rotating the metal core covered with the inorganic coating layer, a certain amount of polyimide varnish R (solid content 18% by mass, viscosity 150) produced by Ube Industries is applied to the surface of the core.
As shown in FIG. 2, the polyimide precursor solution (poise) was dropped while the container 23 was moved at a constant speed in the axial direction of the metal core, and a plate 24 was used to deposit the solution.
The polyimide varnish R easily became a solution coating film of a polyimide precursor.

Then, the metal core body on which the coating film of the polyimide precursor solution is formed is dried at 120 ° C. for 30 minutes, heated to 380 ° C. and heated at 380 ° C. for 3 hours to remove the solvent. At the same time, imidization was performed, and finally, after cooling to room temperature, the polyimide seamless tubular article was removed from the metal core body. The obtained polyimide seamless tubular article has a thickness of 40 ± 2 μm, a ten-point average roughness Rz of the surface of 0.6 μm, a friction coefficient of the surface of 0.35, and a friction coefficient of the back surface of 0. It was 20.

Example 2 An aluminum tube having an arithmetic mean roughness Ra of 0.7 μm, an outer diameter of 68 mm and a thickness of 1 mm was used as a metal core body, and Aerodac G manufactured by Nippon Acheson Co., Ltd. was uniformly applied by spraying. After drying at room temperature, a metal core covered with a coating layer composed of inorganic particles and a resin component was obtained. The thickness of the coating layer is 1 μm,
The surface roughness of the metal core covered with the coating layer was 0.5 μm in terms of arithmetic average roughness Ra.

Polyimide varnish R was applied to the metal core covered with the coating layer in the same manner as in Example 1. At this time, the polyimide varnish R easily became a coating film of the solution of the polyimide precursor. Then, a polyimide seamless tubular product was obtained in the same manner as in Example 1. The obtained polyimide seamless tubular product has a thickness of 40 ± 2μ.
m, the ten-point average roughness Rz of the surface was 0.2 μm, the coefficient of friction of the surface was 0.40, and the coefficient of friction of the back surface was 0.20.

(Example 3) An aluminum tube having an arithmetic mean roughness Ra of 1.0 μm, an outer diameter of 68 mm and a thickness of 1 mm was used as a metal core, and a whity coat of Odec Co., Ltd. was uniformly applied by spraying, After drying at room temperature, a metal core covered with a coating layer composed of inorganic particles and a resin component was obtained. The thickness of the coating layer is 1 μm,
The surface roughness covered with the coating layer is the arithmetic average roughness R
It was 0.5 μm in a.

Polyimide varnish R was applied to the metal core covered with the coating layer in the same manner as in Example 1. At this time, the polyimide varnish R easily became a coating film of the solution of the polyimide precursor. Then, a polyimide seamless tubular product was obtained in the same manner as in Example 1. The thickness of the obtained polyimide seamless tubular product is 41 ± 2μ.
m, the ten-point average roughness Rz of the surface was 0.23 m, the coefficient of friction of the surface was 0.40, and the coefficient of friction of the back surface was 0.25.

Comparative Example 1 An aluminum tube having an arithmetic mean roughness Ra of 1.0 μm, an outer diameter of 68 mm and a thickness of 1 mm was used as a metal core body, and after degreasing the coated surface of the metal core body, Shin-Etsu Chemical Co., Ltd. Silicon release agent KS-70
0 (nonvolatile content 14.4% by mass) was applied. After drying at room temperature, it was dried at 150 ° C. for 5 minutes. Example 1
A solution of the polyimide precursor was applied in the same manner as in 1. However, cissing occurred and the polyimide precursor coating could not be formed.

Comparative Example 2 An aluminum tube having an arithmetic mean roughness Ra of 1.0 μm, an outer diameter of 68 mm and a thickness of 1 mm was used as a metal core body, and after degreasing the coating surface of the metal core body, Shin-Etsu Chemical Co., Ltd. Silicone type is a release agent KS-7
00 was applied. And after drying at room temperature, 30 at 350 ℃
Dry for minutes. Polyimide varnish R was applied to this in the same manner as in Example 1. The phenomenon of cissing that occurred in Comparative Example 1 did not occur, and a film of the polyimide precursor could be formed.

Then, a polyimide seamless tubular product was obtained in the same manner as in Example 1. The obtained polyimide seamless tubular product had a thickness of 41 ± 5 μm, a ten-point average roughness Rz on the surface of 0.8 μm, and a friction coefficient of 0.40 on both the front and back surfaces, and was used as a fixing belt. Then, wrinkles occurred in the polyimide seamless tubular article.

(Comparative Example 3) An aluminum tube having an outer diameter of 68 mm and a thickness of 1 mm which was mirror-finished by buffing was used as a metal core body, and after degreasing the coated surface of the metal core body, Shin-Etsu Chemical Co., Ltd. ) Silicone coating was coated with a release agent KS-700, dried at room temperature and then dried at 350 ° C. for 30 minutes. A solution of polyimide varnish R was applied in the same manner as in Example 1. Then, under the same conditions as in Example 1, the solvent was removed and imidization was performed. However, due to the gas components generated in the process of removing the solvent and performing imidization,
Unevenness was generated on the surface of the polyimide seamless tubular product, and a normal polyimide seamless tubular product could not be obtained.

Comparative Example 4 An aluminum tube having an arithmetic mean roughness Ra of 2.5 μm, an outer diameter of 68 mm and a thickness of 1 mm was used as a metal core body, and after degreasing the coated surface of the metal core body, Shin-Etsu Chemical Co., Ltd. Silicon release agent KS-70
0 was applied. After drying at room temperature, it was dried at 350 ° C. for 30 minutes. A solution of a polyimide precursor was applied to this in the same manner as in Example 1.

Then, a polyimide seamless tubular product was obtained by the same method as in Example 1. The obtained polyimide seamless tubular article had a thickness of 41 ± 7 μm, a ten-point average roughness Rz on the surface of 1.6 μm, and a friction coefficient of 0.40 on both the front and back surfaces. Since the thickness was 41 ± 7 μm, it could not be used as the fixing belt of the fixing device.

Comparative Example 5 As the metal core body, stainless steel having a surface roughness Ra of 2.5 μm, an outer diameter of 68 mm and a thickness of 1 mm was used, and the surface of the metal core body was coated with polytetrafluoroethylene resin. Polyimide varnish R was applied to this in the same manner as in Example 1. Then, Example 1
Under the same conditions as the above, the solvent was removed and imidization was performed.Finally, after cooling to room temperature, the polyimide seamless tubular article was tried to be removed from the core, but the polyimide coating on the core surface swelled locally. Since many parts were generated, a normal polyimide seamless tubular product could not be obtained.

[0075]

INDUSTRIAL APPLICABILITY The present invention forms a film of a low friction material on the back surface of a seamless tubular article made of a heat resistant resin composition such as polyimide, and has a highly accurate seamless tubular article with low friction on the back surface of the seamless tubular article. And, the product yield is high,
It is possible to provide a low-cost method for producing a seamless tubular product and an image forming apparatus using the obtained seamless tubular product.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a metal core body having an inorganic coating layer and a coating layer of a polyimide precursor formed on its surface.

FIG. 2 (A) is a schematic view showing a method of applying the polyimide precursor solution of the present invention to a metal core covered with an inorganic coating layer. (B) is a cross-sectional view of a coated portion of the metal core body covered with the inorganic coating layer described in (A).

FIG. 3A is a cross-sectional view of the polyimide seamless tubular article of the present invention as seen in the longitudinal direction. (B) is
It is an aa sectional view of the polyimide seamless tubular article described in (A).

FIG. 4 is a configuration diagram of a static / dynamic friction coefficient meter manufactured by Kyowa Interface Science Co., Ltd., which is an example of a static / dynamic friction coefficient meter that can be used in the present invention.

FIG. 5 is a schematic view showing an example of a full-color image forming apparatus using the polyimide seamless tubular article of the present invention.

FIG. 6 is a schematic view of a fixing device using a polyimide seamless tubular material.

[Explanation of symbols]

11 Metal Core 12 Inorganic Coating Layer 13 Coating Layer 21 Metal Core 22 Covered with Inorganic Coating Layer 22 Plate 23 Container 24 Polyimide Precursor Solution 30 Applied to Surface of Metal Core 21 30 Polyimide Seamless Tubular Object 31 Polyimide layer 32 Inorganic particle layer 41 Seamless tubular object 42 Fixing table 43 Steel ball 44 Zero adjustment balance 45 Load cell 46 Load 51 Photoreceptor 52 Corona charger 54 Intermediate transfer member 55 Developing device 56 Transfer device 57 Cleaning means 60 Recording medium 61 Polyimide Seamless Tubular Material 62 Nip Pad 63 Nip Head 64 Support 65 Heating Roll

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 G03G 15/16 4F205 15/20 102 15/20 102 21/00 350 21/00 350 // B29K 79:00 B29K 79:00 B29L 9:00 B29L 9:00 23:00 23:00 F Term (reference) 2H033 AA31 BA12 BB01 BB30 BB31 BE06 2H035 CA05 CB06 2H071 BA42 DA09 DA12 DA16 2H200 FA13 GA24 GB25 JA25 JA26 JA27 JB07 JB45 JB46 JB47 LC02 LC04 MA04 MA17 MA20 MC05 MC06 4D075 AC06 AC65 AC91 AE03 BB14Y BB26Z CA06 CA18 CA22 DA15 DA20 DB04 DB07 DC19 DC21 DC24 EA07 EB07 EB13 EB14 GB11 AG03 AG02 AB11 AG03 AB02 A11A40 AB11 A40 AB40 A11A40 AB14 A11A40 AB40 A01A40 AB40 A11A40 AB11 GF02 GN29 GW06

Claims (10)

[Claims] 1. A method for producing a seamless tubular article made of a heat-resistant resin composition, comprising a liquid heat-resistant resin composition on the surface of a metal core covered with a coating layer made of inorganic particles and a resin component. A coating step of applying, a solidification step of solidifying or curing the liquid heat-resistant resin composition applied to the surface of the metal core, the solidified or cured heat-resistant resin composition, the coating layer And a separation step of separating the metal core from the metal core together with the inorganic particles therein. 2. The applying step is a step of applying the polyimide precursor solution as the liquid heat-resistant resin composition to a uniform thickness on the surface of the metal core covered with the coating layer, The method for producing a seamless tubular article according to claim 1, wherein the solidifying step is a step of heating the applied polyimide precursor solution to cause an imide conversion reaction. 3. The method for producing a seamless tubular product made of a heat-resistant resin composition according to claim 2, wherein a conductive agent is dispersed in the polyimide precursor solution. 4. The coating layer is made of a resin composition to which an inorganic compound is added.
4. The method for producing a seamless tubular article according to any one of 3 to 3. 5. The application step comprises rotating the metal core and moving a fixed amount of liquid heat-resistant resin in the axial direction of the metal core covered with the coating layer at a constant speed. The method for producing a seamless tubular article according to any one of claims 1 to 4, which is a step of applying the composition to the surface of the metal core. 6. A seamless tubular article produced by the method for producing a seamless tubular article according to claim 1. 7. The seamless tubular article according to claim 6, wherein the relationship between the friction coefficient μ1 on the front surface and the friction coefficient μ2 on the back surface is μ1> μ2. 8. The seamless tubular article according to claim 6, wherein a friction coefficient μ2 of the back surface of the seamless tubular article is 0.3 or less. 9. An image forming apparatus using the seamless tubular article according to claim 6. 10. An image forming apparatus including a fixing device of a belt fixing system, wherein the fixing belt of the fixing device comprises:
An image forming apparatus according to claim 9, wherein the seamless tubular article according to any one of claims 6 to 8 is used.