JP2005088272A - Manufacturing method of seamless tubular article, cylindrical core body, seamless tubular article and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a seamless tubular article capable of easily manufacturing a seamless belt or the like, not causing the repelling phenomenon or flow phenomenon of a liquid heat-resistant resin composition, preventing the adhesion of a resin film and a core body or the shrinkage of the resin film caused by heating, imide conversion or the like and capable of achieving film forming stability and high dimensional precision, a cylindrical core body, the seamless tubular article and an image forming apparatus wherein the seamless tubular article is used. <P>SOLUTION: This manufacturing method of the seamless tubular article includes a coating process for coating the outer peripheral surface of the cylindrical core body with the cylindrical core body, a curing process for heating the liquid heat-resistant resin composition applied to the outer peripheral surface of the cylindrical core body to form the resin film and a separation process for separating the resin film from the cylindrical core body and is characterized in that the ratio (θ1/θ2) of the surface water contact angle (θ1) in the entire peripheral region of the end part of the cylindrical core body and the surface water contact angle (θ2) of the entire pheripheral region of the central part of the cylindrical core body is 0.5-0.9. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a seamless tubular material (seamless belt, seamless tube) preferably used for a transfer belt, a transfer roll, a fixing belt, and the like in an image forming apparatus using an electrophotographic system such as a copying machine or a printer, and a manufacturing method thereof, The present invention relates to a metallic cylindrical core used in the manufacturing method and an image forming apparatus.

  In an electrophotographic apparatus such as an image forming apparatus using an electrophotographic method, a rotating body made of metal, various plastics, or rubber is used for a photoreceptor, a transfer belt, a fixing belt, or the like. In order to reduce the size and improve the performance of the device, it may be preferable that these rotating bodies can be deformed to some extent, but in that case, a tubular body made of a plastic film having a small thickness is used. At that time, if there is a seam in the tubular material, a defect due to the seam occurs in the formed image. Therefore, it is necessary to use a seamless tubular material (seamless tubular material).

  As for the method of producing a seamless tubular product, for example, a method of forming a film on the inner peripheral surface of a mold by a rotational molding method, a method of melting and extruding a resin in a ring shape, and dipping a resin solution on the outer surface of a cylindrical mold There has been proposed a method of applying a certain thickness and pulling out a mold after heating film formation (for example, see Patent Documents 1 to 3).

  Examples of the resin material that forms the seamless tubular material include polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, and polyphenylene sulfide. Among these, strength, heat resistance, dimensions A polyimide resin is particularly preferably used from the viewpoint of stability.

  By the way, a problem in producing a seamless tubular product using the polyimide is that extrusion molding, inflation, or vacuum forming cannot be performed like a seamless tubular product made of a thermoplastic resin. Therefore, as a method for producing a seamless tubular product of polyimide, a method in which a polyamic acid solution (polyimide precursor solution) as a precursor is applied to the surface of a mold or the like and demolded at the stage of imidization by heating must be employed. I do not get.

  On the other hand, in these seamless tubular manufacturing methods, metals such as aluminum and stainless steel are generally used as the material of the mold (cylindrical core). However, polyimide resin is a resin that is used as an adhesive. When a polyamic acid solution is applied to the mold surface and converted to imide by heating, the polyimide seamless tubular material will adhere or adhere to the mold. It is difficult to remove the seamless tubular product of polyimide.

  In this way, when a polyimide precursor solution is applied to the surface of a mold (cylindrical core) and heated to convert the imide to obtain a seamless tubular product, the mold and the seamless tubular product are smoothly separated. For this purpose, a method of covering the surface of the mold with a releasable resin and reducing the adhesion energy of the surface is conceivable. However, as a side effect of reducing the adhesive energy on the core surface, repellency and flow phenomena may occur when a liquid polyimide precursor is applied to the core surface, and solvent volatilization may occur during heating and imide conversion. In addition, there is a problem that strong shrinkage occurs due to the separation of water during the condensation reaction.

The above shrinkage causes streaky irregularities on the surface of the heat-resistant seamless belt (seamless tubular material), and the end of the heat-resistant seamless belt not only becomes thicker, but also has conductivity. However, due to the denseness of the conductive agent at the end, there also occurs a problem that the electric resistance is lower than that at the center.
JP-A-60-170862 JP-A-6-202513 JP-A-6-222695

The object of the present invention is to solve the above-mentioned problems of the prior art.
That is, the present invention does not cause the repellency phenomenon or flow phenomenon of the liquid heat-resistant resin composition, prevents adhesion between the resin film and the core, and shrinkage due to heating, imide conversion, etc., and has high film formation stability. It is an object of the present invention to provide a method for producing a seamless tubular product, a cylindrical core, a seamless tubular product, and an image forming apparatus using the seamless tubular product, which can easily produce a seamless belt capable of achieving dimensional accuracy. .

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> By applying a liquid heat resistant resin composition to the outer peripheral surface of a metallic cylindrical core, and heating the liquid heat resistant resin applied to the outer peripheral surface of the cylindrical core A method for producing a seamless tubular article, comprising: a curing step for forming a resin coating; and a separation step for separating the resin coating from the cylindrical core,
The ratio (θ1 / θ2) between the surface water contact angle (θ1) in the entire circumference of the end portion of the cylindrical core and the surface water contact angle (θ2) in the entire circumference of the central portion of the cylindrical core is 0. A method for producing a seamless tubular product characterized by being in the range of .5 to 0.9.

<2> The surface water contact angle (θ1) of the entire circumference of the end portion of the cylindrical core is 50 ° or more, and the surface water contact angle (θ2) of the entire circumference of the center of the cylindrical core is 60. It is the range of -110 degrees, It is a manufacturing method of the seamless tubular product as described in <1>.

<3> The method for producing a seamless tubular product according to <1> or <2>, wherein the cylindrical core has a coating layer containing a silicone resin composition on an outer peripheral surface.

<4> The resin coating is mainly composed of polyimide, and after the polyimide precursor solution is uniformly applied to the outer peripheral surface of the cylindrical core and heated to cause an imide conversion reaction, The method for producing a seamless tubular product according to any one of <1> to <3>, which is a separated resin film.

<5> The seamless tubular product according to any one of <1> to <4>, wherein the liquid heat-resistant resin composition is an aromatic polyimide precursor formed by dispersing a conductive agent. It is a manufacturing method.

<6> A liquid heat-resistant resin composition is applied to the outer peripheral surface of the cylindrical core, and the applied liquid heat-resistant resin is heated to form a resin film. A metallic cylindrical core used in a method for producing a seamless tubular product to be separated,
The ratio (θ1 / θ2) between the surface water contact angle (θ1) of the entire circumference of the end portion and the surface water contact angle (θ2) of the entire circumference of the central portion is in the range of 0.5 to 0.9. This is a characteristic cylindrical core.

<7> A seamless tubular product produced by the method for producing a seamless tubular product according to any one of <1> to <5>.

<8> An image forming apparatus including at least a charging unit, a developing unit, a transfer unit, and a fixing unit,
An image forming apparatus using the seamless tubular material according to <7> as a member constituting at least one of the charging unit, the developing unit, the transfer unit, and the fixing unit.

  According to the method for producing a seamless tubular body of the present invention, there is no occurrence of a repellency phenomenon or a flow phenomenon of a liquid resistant resin composition, it is possible to prevent shrinkage due to adhesion and heating between the resin film and the core, and imide conversion, A seamless belt having high film forming stability and high dimensional accuracy can be easily manufactured.

Hereinafter, the present invention will be described in detail.
<Seamless tubular body manufacturing method, cylindrical core>
The method for producing a seamless tubular body of the present invention includes a coating step of applying a liquid heat-resistant resin composition to an outer peripheral surface of a metal cylindrical core, and a liquid applied to the outer peripheral surface of the cylindrical core. A method for producing a seamless tubular article, comprising: a curing step of heating a heat-resistant resin to form a resin coating; and a separation step of separating the resin coating from the cylindrical core. The ratio (θ1 / θ2) of the surface water contact angle (θ1) in the entire periphery of the end portion to the surface water contact angle (θ2) in the entire periphery of the central portion of the cylindrical core is 0.5 to 0.9. It is a range.

  When a liquid heat-resistant resin composition is applied to the outer peripheral surface of a metal cylindrical core and cured by heating, a liquid heat-resistant resin composition is obtained as described above. Strong shrinkage occurs due to the volatilization of the solvent during heating and imide conversion and the removal of water during the condensation reaction. This contraction is triggered by the end of the cylindrical core that is the free end. Accordingly, the shrinkage can be prevented if the coating film of the heat-resistant resin composition or the adhesion and adhesion of the coating to the surface of the cylindrical core are higher at the end of the cylindrical core.

  In this case, when the surface water contact angle of the entire circumference of the end portion of the cylindrical core is θ1, and the surface water contact angle of the entire circumference of the central portion of the cylindrical core is θ2, the ratio between both (θ1 / θ2) If the relationship of (θ1 / θ2) <1, that is, if the surface water contact angle of the end portion is smaller than that of the central portion, the end portion becomes better wettable than the central portion, and the liquid heat-resistant resin composition Shrinkage can be prevented because the coating film or the force of the coating film remaining on the end surface increases.

  Here, the end part perimeter area of the core body means the end part side perimeter part of the core material in the area where the heat resistant resin composition is applied. Specifically, the heat resistant resin composition is applied. This means the entire peripheral portion within a range of 15% or less of the length in the core axis direction of the entire coating region (coating region length) from the end of the applied region. Moreover, the said edge part means the both ends of a cylindrical core. On the other hand, the central portion refers to a portion near the center of the cylindrical core, but in the present invention, the core surface water contact angle of the portion corresponding to the heat-resistant resin composition application region other than the end portion is the center. Is substantially the same as the water contact angle θ2.

  In the present invention, by making the ratio of θ1 and θ2 (θ1 / θ2) in the range of 0.5 to 0.9, shrinkage of the heat-resistant resin composition can be effectively prevented. In addition, the resin film can be easily separated from the cylindrical core body after curing without the need to insert a spatula or the like between the resin film and the core body in order to facilitate separation, for example.

  Further, in the present invention, since the above θ1 / θ2 is satisfied over the entire circumference, for example, when the end portion of the release agent layer formed on the surface of the cylindrical core is partially peeled off Thus, the shrinkage | contraction in an edge part and the nonuniformity of a non-shrinkable part are not produced, but the resin film with a uniform characteristic can be produced without waste.

When the θ1 / θ2 is less than 0.5, there is a large difference between the force that the liquid heat-resistant resin composition tries to stay on the end surface and the force that tends to shrink on the center surface, and the boundary between the end surface and the center portion. Thus, the liquid heat-resistant resin composition is repelled and split. Conversely, when θ1 / θ2 exceeds 0.9, the force with which the liquid heat-resistant resin composition tries to stay on the surface of the end cannot withstand the force of shrinking on the surface of the central portion, and the shrinkage cannot be prevented. .
The θ1 / θ2 is preferably in the range of 0.5 to 0.9, and more preferably in the range of 0.65 to 0.75.

  The water contact angle of the surface was measured by using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd .: CA-X) at a temperature of about 25 ° C. and 50% RH, with pure water being applied to the surface of each part of the cylindrical core. 3.1 μl was dropped and the contact angle after 15 seconds was determined. The measurement was performed at four points in the circumferential direction at the end and center, and the average value of these was taken as the contact angle.

  In the present invention, θ1 and θ2 at the end and center of the cylindrical core body must be substantially constant in the circumferential direction, and variations in measured values when measured in the circumferential direction are θ1, The average value of θ2 is preferably within ± 3 °.

  In the present invention, the surface water contact angle (θ1) of the entire circumference of the end portion of the cylindrical core is 50 ° or more, and the surface water contact angle (θ2) of the entire circumference of the central portion of the cylindrical core. ) Is preferably in the range of 60 to 110 °.

  By setting the above θ1 to 50 ° or more, the liquid heat-resistant resin composition applied to the surface of the cylindrical core body can obtain a force that remains on the end surface of the cylindrical core body, and during heating and imide conversion It is possible to prevent strong shrinkage due to the volatilization of the solvent and the separation of water during the condensation reaction, and the heat resistant resin composition can be easily separated from the surface of the cylindrical core.

  In addition, the surface water contact angle (θ2) of the entire circumference of the central part of the cylindrical core is 110 ° in order to prevent repellency and flow phenomena that occur when the liquid heat resistant resin composition is applied to the core surface. The following is preferable. In order to prevent adhesion between the heat-resistant resin composition and the cylindrical core, θ2 is preferably 60 ° or more.

Hereinafter, the manufacturing method of the seamless tubular body of this invention is demonstrated for every process.
(Coating process)
The coating step in the present invention refers to a step of forming a coating layer by coating a liquid heat-resistant resin composition on the outer peripheral surface of a metallic cylindrical core having surface characteristics as described above.

-Cylindrical core-
As the material of the metallic cylindrical core, for example, aluminum, copper, stainless steel, etc. are preferably used, but it is easy to separate the resin coating from the core using the difference in thermal expansion between the resin coating and the core. It is more preferable to use aluminum having a high coefficient of thermal expansion.

  In addition, when the cylindrical core is aluminum, when it is heated to 350 ° C., the strength is reduced and deformation is likely to occur. Such thermal deformation of aluminum is likely to occur when strain is accumulated during cold working into a cylindrical core shape. In order to remove such distortion, there is a method of annealing (annealing) aluminum. However, since thermal deformation also occurs by annealing, it is necessary to perform processing to a predetermined shape thereafter. Examples of the annealing method include a method of heating an aluminum material in a range of 350 to 400 ° C. and naturally cooling in the air.

  As the cylindrical core body, those having various lengths and various outer diameters can be used. In the present invention, the surface water contact between the central portion and the end portion of the core body can be easily performed by the method described later. Since the treatment for separating the resin film can be performed by changing the angle, for example, a small cylindrical core having an outer diameter of about 20 mm can also be used.

  The method for controlling the surface water contact angle of these cylindrical cores as described above is not particularly limited. For example, a releasable resin composition or a coupling agent on the outer peripheral surface of the cylindrical core body. A coating layer is formed by coating the surface treatment agent and the like, and ultraviolet irradiation is performed only on the end side of the coating layer to change the water contact angle between the central portion and the end portion.

  The change in the water contact angle due to UV irradiation is considered to be based on the oxidation of the coating layer surface by UV irradiation. When a chemically stable fluororesin or inorganic ceramic coating layer is formed, UV irradiation is performed. Even after treatment, the water contact angle does not fluctuate easily.

For this reason, it is preferable to use a silicone resin composition that is susceptible to oxidation as the coating layer.
As the silicone resin composition, for example, KS700 manufactured by Shin-Etsu Chemical Co., Ltd. or SEPA-COAT can be used.

As thickness of the coating layer in this invention, the range of 0.5-10 micrometers is preferable, and the range of 1-5 micrometers is more preferable. The ultraviolet irradiation amount is preferably in the range of 8 to 15 mW / cm ^{2 and in} the range of 30 to 180 seconds.

The surface water contact angle can be controlled by changing the solid content of the coating layer only at the end of the cylindrical core or applying another coating agent to the end.
As described above, the cylindrical core used in the method for producing a seamless tubular product of the present invention can be obtained.

-Liquid heat-resistant resin composition-
The seamless tubular product of the present invention is produced by applying a liquid heat resistant resin composition to the outer peripheral surface of the cylindrical core.
The liquid heat-resistant resin composition is not particularly limited, and examples thereof include polyimide, polyphenylene oxide, and aromatic polyamide (including their precursors). Among these, as materials for seamless belts, etc. Polyimide resin is particularly preferably used in terms of strength, dimensional stability, heat resistance and the like. Therefore, it is preferable that the resin film which becomes the seamless tubular product of the present invention contains polyimide as a main component.

-Polyimide precursor solution-
Hereinafter, as a liquid heat-resistant resin composition in the present invention, a polyimide precursor solution for producing a polyimide resin film will be described as an example.
The polyimide precursor solution that can be used in the present invention is not particularly limited as long as it consists of a carboxylic acid and an amine, but in particular, the following aromatic tetracarboxylic acid component and aromatic diamine component (aromatic polyimide precursor): Body) and those obtained by reaction in an organic polar solvent are preferably used.

  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′-diphenyl ethertetra Carboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-azobenzenetetracarboxylic acid, bis (2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3,4-di Carboxymethyl phenyl) hexafluoropropane and the like, may be a mixture of these tetracarboxylic acids.

  The aromatic diamine component is not particularly limited, and m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine, 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'-diaminophenylsulfone, 4,4'-diaminoazo Benzene, 4,4'-diaminodiphenylmethane, beta, beta-bis (4-amine phenyl) propane.

  Examples of the organic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, and the like. These organic polar solvents can be mixed with phenols such as cresol, phenol and xylenol, and hydrocarbons such as hexane, benzene and toluene, if necessary. A polar solvent may be used independently or may be used in mixture of 2 or more types.

The polyimide seamless tubular product of the final product may be required to have conductivity in accordance with the purpose of use. In that case, a conductive agent is added to and dispersed in the polyimide precursor solution. It is preferable to impart conductivity to the polyimide seamless tubular material.
Examples of the conductive agent include an electron conductive conductive agent and an ion conductive conductive agent.

Examples of the electron conductive conductive agent include metals or alloys such as carbon black, graphite, aluminum, nickel, and copper alloys; tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide, and tin oxide-antimony oxide composite oxide. Examples thereof include metal oxides.
Examples of the ion conductive conductive agent include sulfonates, ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants.

Further, as a means for imparting conductivity to the polyimide seamless tubular product of the final product, a method of blending a conductive polymer with the polyimide precursor solution, and the like can be mentioned.
Examples of the conductive polymer include a copolymer of (meth) acrylate having a carboxyl group binding a quaternary ammonium base and another compound (for example, styrene); a maleimide binding a quaternary ammonium base, and a methacrylate. Polymers that bind quaternary ammonium bases such as copolymers with polyethylene; Polymers that bind alkali metal salts of sulfonic acids such as sodium polysulfonate; Polyethylene oxide, polyethylene glycol-based polyamide copolymers, polyethylene oxy-epichlorohydrin copolymer Polymers that bind at least a hydrophilic unit of an alkyl oxide in the molecular chain such as a block polymer having a polyether as a main segment, and the like, and further, as an electron conductive system conductive agent, Polyaniline, po Thiophene, polyacetylene, can be mentioned polypyrrole, polyphenylene vinylene may be used These conductive Porima undoped state or doped state.
The resistance value described later can be stably obtained by using one or two or more of the above-described conductive agent or conductive polymer and surfactant.

  The polyimide precursor solution has a viscosity of 5 to 100 Pa.s. s is preferable, and more preferably 10 to 20 Pa.s. A range of s is more preferable. The polyimide precursor solution has a viscosity of 5 to 100 Pa.s. The range of s is convenient and preferable for forming a uniform film thickness.

  It is preferable to uniformly apply the polyimide precursor solution to the surface of the metallic cylindrical core. Here, uniformly applying means not only applying the polyimide precursor solution uniformly in composition but also applying the film thickness uniformly.

The method for uniformly applying is not particularly limited, but the following application method is preferable in that the polyimide precursor solution can be efficiently and reasonably applied to a substantially uniform thickness. Such a preferred polyimide precursor solution coating method will be described with reference to the drawings.
FIG. 1A is a schematic view showing a method of applying the polyimide precursor solution in the present invention to the outer peripheral surface of a cylindrical core body whose surface water contact angle is controlled. On the other hand, FIG. 1 (B) is a cross-sectional view of the coated portion of the cylindrical core body shown in FIG. 1 (A). In FIG. 1, 51 is a cylindrical core body having a controlled surface water contact angle, 52 is a plate, 53 is a container, and 54 is a polyimide precursor solution.

In this method, while rotating the cylindrical core body 51 at a constant speed in the direction of arrow A, a fixed amount of polyimide precursor solution is applied to the surface of the cylindrical core body 51 from the container 53 containing the polyimide precursor solution 54. It is a method of dripping and applying this while leveling the plate 52 in contact with the surface of the cylindrical core 51, and as a result, the uniform polyimide precursor solution 54 is applied to the surface of the cylindrical core 51. To be applied.
In the present invention, the method of applying the polyimide precursor solution to the outer peripheral surface of the cylindrical core is not limited to this method, and other methods such as dip coating may be used.

(Curing process)
In this step, for example, in the case of forming a polyimide resin film, the polyimide precursor film is preferably heated in the range of 300 to 450 ° C., more preferably around 350 ° C., for 20 to 60 minutes. Can be formed. During the heating reaction, if the aprotic polar solvent remains, the polyimide resin film may swell, so it is preferable to completely remove the residual solvent before reaching the final heating temperature. Specifically, before heating, the solvent is dried by heating at a temperature in the range of 150 to 200 ° C. for 30 to 60 minutes, and then the temperature is increased stepwise or at a constant rate. It is preferable to form a polyimide resin film.

  At this time, in the present invention, the surface water contact angle is lower at the end than at the center of the cylindrical core, and the adhesion and adhesion of the coating film and the resin film are high in the entire circumference of the end. Therefore, the film does not shrink due to the heating reaction, and no non-uniform shrinkage is observed.

In the present invention, regarding the shrinkage of the coating that occurs before and after the heating reaction, the axial shrinkage of the cylindrical core relative to the coating of the resin coating is preferably 6% or less, and preferably 3% or less. More preferred. If the shrinkage rate exceeds 6%, the axial film thickness displacement of the cylindrical core may be 10 μm or more, and the axial volume resistance displacement may be 0.5 digits or more.
The axial contraction rate of the cylindrical core with respect to the coating film of the resin coating refers to the axial length of the cylindrical core body of the resin coating C, and the axial length of the cylindrical core body of the coating film. When D, the shrinkage ratio [(D−C) / D] × 100 is obtained.

(Separation process)
After the heating reaction, the seamless tubular article of the present invention can be obtained through this step of cooling the cylindrical core body to room temperature and peeling off the formed resin film. In this step, after cooling, the cylindrical core contracts more than the resin coating, so that the resin coating can be extracted from the cylindrical core. At that time, in the present invention, the surface water contact angle at the end of the cylindrical core body is set to a certain value or more, so it is not difficult to separate the resin coating, and at least one of the ends attached to the both ends of the cylindrical core body. There is no need to insert a sheet or the like into the part.

The extracted resin film may be inferior in film thickness uniformity at both ends or may have fragments of the film attached thereto, and the portion is cut as an unnecessary portion. In the present invention, the unnecessary portion is preferably in the range of 30 to 40 mm from the end.
An unnecessary portion of the end is cut to obtain the seamless tubular product of the present invention, but drilling (punching) processing, rib attaching processing, or the like may be performed as necessary.

<Seamless tubular material>
According to the method for producing a seamless tubular product of the present invention as described above, since the ratio θ1 / θ2 of the surface water contact angle of the cylindrical core body is satisfied in a certain range over the entire circumference of the core body, A seamless belt (seamless tubular material) that can prevent adhesion between the coating and the core, shrinkage due to heating, imide conversion, etc., and achieve film formation stability and high dimensional accuracy can be easily manufactured. In addition, for example, the release agent layer formed on the surface of the cylindrical core body does not cause shrinkage at the end portion and unevenness of the non-shrinkage portion as in the case where the end portion is partially peeled off, and the characteristics are A uniform resin coating (seamless tubular product) can be produced without waste.

  About the uniformity of the film thickness of the obtained seamless tubular product, the film thickness displacement in the axial direction of the cylindrical core is preferably within 7 μm, and more preferably within 5 μm. When the film thickness displacement exceeds 7 μm, for example, when used as an intermediate transfer belt, color misregistration of the color toner may occur.

As for the uniformity of the volume resistivity when the conductivity is imparted to the seamless tubular material, the displacement of the volume resistance value in the axial direction of the cylindrical core is preferably within 0.5 digits, preferably 0.3 digits. Is more preferable. If the volume resistance displacement exceeds 0.5 digits, for example, when used as an intermediate transfer belt, color toner density unevenness may occur.
The volume resistivity can be measured using a circular electrode (for example, “HRS probe” of Hirester IP manufactured by Mitsubishi Oil Chemical Co., Ltd.) in an environment of 23 ° C. and 55% RH. The measurement conditions were a load of 1.0 kg, a voltage of 100 V, and a charge time of 10 seconds.

  In addition, the evaluation regarding the uniformity of the film thickness and the volume resistivity is performed by measuring at least 3 points in the circumferential direction of the belt (seamless tubular product) and 9 or more points in the axial direction, The volume resistance displacement refers to the difference between the maximum value and the minimum value in the measured value.

  The surface roughness of the seamless tubular product is preferably such that the ten-point average roughness Rz is in the range of 0.01 to 10 μm in terms of toner cleaning properties, paper peelability, and the like. A range of 5 μm is more preferable.

  The inner diameter of the seamless tubular material is determined in accordance with the outer diameter of the cylindrical core, and the inner diameter of the seamless tubular material is preferably in the range of 10 mm to 1000 mm, and in the range of 15 mm to 600 mm. It is more preferable that When the inner diameter of the seamless tubular material is in the range of 10 mm to 1000 mm, it is preferable for forming a uniform film thickness.

  Furthermore, the thickness of the seamless tubular product is preferably in the range of 10 to 100 μm, and more preferably in the range of 20 to 80 μm. When the thickness of the seamless tubular product is in the range of 10 to 100 μm, it is preferable for forming a uniform film thickness.

<Image forming apparatus>
The image forming apparatus of the present invention is an image forming apparatus including at least a charging unit, a developing unit, a transfer unit, and a fixing unit, and as a member constituting any one or more of these units, the seamless of the present invention. If a tubular thing is used, it will not be limited in particular. For example, a normal monocolor image forming apparatus containing only a single color toner in a developing device, or a color image in which a toner image carried on the surface of an image carrier such as a photosensitive drum is repeatedly subjected to primary transfer sequentially to an intermediate transfer member Examples thereof include a tandem type color image forming apparatus in which a plurality of image carriers each having a developing device for each color are arranged in series on an intermediate transfer member.

Hereinafter, a color image forming apparatus that repeats primary transfer will be described as an example of the image forming apparatus of the present invention. FIG. 2 is a schematic configuration diagram showing an example of the image forming apparatus of the present invention.
2 includes a photosensitive drum 1 as an image carrier, a transfer belt 2 as an intermediate transfer member, a bias roll 3 as a transfer electrode, a tray 4 for supplying recording paper as a recording medium, and a Bk (black). ) Developing unit 5 using toner, developing unit 6 using Y (yellow) toner, developing unit 7 using M (magenta) toner, developing unit 8 using C (cyan) toner, belt cleaner 9, peeling claw 13, belt rolls 21, 23 And 24, a backup roll 22, a conductive roll 25, an electrode roll 26, a cleaning blade 31, a pickup roll 42, and a feed roll 43. The transfer belt 2 includes a semiconductive belt which is the seamless tubular product of the present invention.

In FIG. 2, the photosensitive drum 1 rotates in the direction of arrow A, and its surface is uniformly charged by a charging device (charging means) (not shown). An electrostatic latent image of the first color (for example, Bk) is formed on the charged photosensitive drum 1 by image writing means such as a laser writing device. This electrostatic latent image is developed by a developing device 5 (developing means) to form a visualized toner image T. The toner image T reaches the primary transfer portion (transfer means) where the conductive roll 25 is arranged by the rotation of the photosensitive drum 1, and an electric field having a reverse polarity is applied to the toner image T from the conductive roll 25. The toner image T is primarily transferred by the rotation of the transfer belt 2 in the direction of arrow B while being electrostatically attracted to the transfer belt 2.
Thereafter, similarly, a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the surface of the transfer belt 2 to form a multiple toner image.

  The multiple toner image transferred to the transfer belt 2 reaches the secondary transfer portion (transfer means) where the bias roll 3 is installed by the rotation of the transfer belt 2. The secondary transfer unit includes a bias roll 3 disposed on the surface side of the transfer belt 2 on which the toner image is carried, a backup roll 22 disposed opposite to the bias roll 3 from the back side of the transfer belt 2, and this It comprises an electrode roll 26 that rotates in pressure contact with the backup roll 22.

  The recording paper 41 (recording medium) is taken out one by one from the recording paper bundle accommodated in the recording paper tray 4 by the pickup roll 42, and is fed between the transfer belt 2 and the bias roll 3 of the secondary transfer section by the feed roll 43. Are fed at a predetermined timing. The toner image carried on the surface of the transfer belt 2 is transferred to the fed recording paper 41 by the pressure contact conveyance by the bias roll 3 and the backup roll 22 and the rotation of the transfer belt 2.

The recording paper 41 to which the toner image has been transferred is peeled from the transfer belt 2 by operating the peeling claw 13 in the retracted position until the primary transfer of the final toner image is completed, and is conveyed to a fixing device (fixing means) (not shown). Then, the toner image is fixed to the recording paper 41 by the pressurization / heating process to be a permanent image.
After the transfer of the multiple toner image to the recording paper 41 is completed, the residual toner is removed by a belt cleaner 9 provided on the downstream side of the secondary transfer portion to prepare for the next transfer. A cleaning blade 31 made of polyurethane or the like is always in contact with the bias roll 3 to remove foreign matters such as toner particles and paper dust adhered during transfer.

In the case of transfer of a single color image, the toner image T that has been primarily transferred is immediately secondarily transferred and conveyed to the fixing device. However, in the case of transfer of a multicolor image by superimposing a plurality of colors, the toner image of each color is primary. The rotation of the transfer belt 2 and the photosensitive drum 1 is synchronized so that the toner images of the respective colors do not shift so that they coincide accurately at the transfer portion.
In the secondary transfer section, an output pressure (transfer voltage) having the same polarity as the polarity of the toner image is applied to the electrode roll 26 that is in pressure contact with the backup roll 22 that is disposed to face the bias roll 3 and the transfer belt 2. As a result, the toner image is transferred to the recording paper 41 by electrostatic repulsion. As described above, an image can be formed.

  The seamless tubular material such as polyimide obtained in the present invention can be used not only as the transfer belt 2, for example, but also as a surface layer of the bias roll 3 or a fixing belt of a belt nip type fixing device, in particular, transfer means or fixing. It can be preferably used as a means.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
(Example 1)
-Fabrication of seamless tubular materials-
An aluminum cylindrical core having an outer diameter of 20 mm and a length of 320 mm is used, and a thickness of a silicone resin composition (manufactured by Shin-Etsu Chemical Co., Ltd .: KS700) is 1 μm on the outer peripheral surface of the cylindrical core. Then, it was uniformly applied and baked at 380 ° C. for 1 hour.

From the position where the distance from the surface of the cylindrical core is 20 mm within the range of 30 mm from both ends of the cylindrical core (the range of 6.7% of the coating area length from the end of the coating area), the light intensity The cylindrical core was irradiated for 120 seconds while being rotated at 60 rpm with a 10 mW / cm ² ultraviolet lamp to perform ultraviolet irradiation treatment. In addition, it masked except 30 mm from the edge part of the said cylindrical core, and it was made not to irradiate with an ultraviolet-ray.

  The average value of the surface water contact angle of the entire peripheral area of the cylindrical core body having the coating layer irradiated with ultraviolet rays is 70 °, and the central part (central part) is not irradiated with ultraviolet rays. The average surface water contact angle of the region was 85 °.

Polyimide precursor in which 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) are reacted in equimolar amounts in N-methyl-2-pyrrolidone (NMP) In a solution (Ube Industries, Ltd .: Euvarnish S, solid content: 18% by weight), dry oxidized carbon black (Degussa: SPECIAL BLACK4) was added in an amount of 23 parts by weight with respect to 100 parts by weight of the polyimide precursor solids. This mixture was added to the same, and the mixture was collided after being divided into two parts with a minimum area of 1.4 mm ² at a pressure of 200 MPa using a collision type disperser (Geanus PY), and again passed through the path divided into two parts five times. To obtain a carbon black-dispersed polyimide precursor solution having a viscosity of 15 Pa · s.

  While rotating the cylindrical core body at 100 rpm, the dispenser in which the outer peripheral surface is filled with the polyimide precursor solution and the scraper are set at a moving speed of 150 mm / min. The said polyimide precursor solution was apply | coated so that thickness might be set to 0.5 mm, moving to the axial direction of a body.

  Then, while rotating this cylindrical core body at 5 rpm, it heated at 120 degreeC for 30 minutes, then, after cooling to normal temperature, it heated at 300 degreeC for 2 hours, and imide conversion was performed with solvent removal. Finally, it was cooled to room temperature, and a polyimide resin film having a thickness of 0.05 mm and a volume resistance of 6.5 logΩ was separated from the cylindrical core.

  The polyimide resin film obtained has a length of 290 mm, a contraction rate in the core axis direction with respect to the coating film of 3%, no repellency, no flow phenomenon, good film formability, and close contact with the core surface And could be easily separated from the core. The film thickness displacement in the core axis direction was 5 μm, and the volume resistance displacement in the core axis direction was 0.3 digits. A polyimide seamless tubular product was obtained by cutting the both ends of this by 30 mm.

-Evaluation-
A sponge roll having a sponge layer formed with a thickness of 20.5 mm and a length of 230 mm was fitted around a stainless steel shaft having a diameter of 12 mm into the polyimide seamless tubular tube to prepare a transfer roll. When this transfer roll was used as a bias roll (secondary transfer roll) of an image forming apparatus (Fuji Xerox Co., Ltd .: DocuPrint C1616), a good image without uneven transfer was obtained.

(Example 2)
In the production of the seamless tubular body of Example 1, it was made of polyimide in the same manner as in Example 1 except that the silicone resin composition applied to the cylindrical core was baked at 300 ° C. for 1 hour and the ultraviolet irradiation time was 180 seconds. A seamless tubular body was produced. At this time, the average value of the surface water contact angles in the entire peripheral area of the end portion of the cylindrical core body was 50 °, and the average value of the surface water contact angles in the entire peripheral area of the central portion was 100 °.

  The obtained polyimide resin coating has a length of 300 mm, a shrinkage ratio in the core axis direction with respect to the coating is 1.7%, has no filming and flow phenomenon, and has good film formability. It was possible to easily separate from the core without adhesion. The film thickness displacement in the core axis direction was 2 μm, and the volume resistance displacement in the core axis direction was 0.1 digit. A polyimide seamless tubular product was obtained by cutting both ends of this product by 35 mm.

  Also, using this polyimide seamless tubular material, a transfer roll was prepared in the same manner as in Example 1 and evaluated as a bias roll with the same image forming apparatus. As a result, a good image without uneven transfer was obtained. It was.

(Example 3)
In the production of the seamless tubular body of Example 1, a polyimide seamless tubular body was produced in the same manner as in Example 1 except that the ultraviolet irradiation time was 90 seconds. At this time, the average value of the surface water contact angle in the entire peripheral area of the end portion of the cylindrical core body was 70 °, and the average value of the surface water contact angle in the entire peripheral area of the central portion was 80 °.

  The obtained polyimide resin coating has a length of 290 mm, a shrinkage ratio in the core axis direction with respect to the coating is 3.3%, has no repellency and flow phenomenon, and has good film formability. It was possible to easily separate from the core without adhesion. The film thickness displacement in the core axis direction was 5 μm, and the volume resistance displacement in the core axis direction was 0.3 digits. A polyimide seamless tubular product was obtained by cutting the both ends of this by 30 mm.

  Also, using this polyimide seamless tubular material, a transfer roll was prepared in the same manner as in Example 1 and evaluated as a bias roll with the same image forming apparatus. As a result, a good image without uneven transfer was obtained. It was.

(Comparative Example 1)
In the production of the seamless tubular body of Example 1, a polyimide seamless tubular body was produced in the same manner as in Example 1 except that the ultraviolet irradiation time was 300 seconds. At this time, the average value of the surface water contact angle in the entire peripheral area of the end portion of the cylindrical core body was 35 °, and the average value of the surface water contact angle in the entire peripheral area of the central portion was 80 °.

  The obtained polyimide resin film had a length of 300 mm, a shrinkage ratio in the core axis direction with respect to the coating film was 0%, had no filming and flow phenomenon, and had good film formability. The resin film could not be separated from the core.

(Comparative Example 2)
In the production of the seamless tubular body of Example 1, it was made of polyimide in the same manner as in Example 1 except that the silicone resin composition applied to the cylindrical core was baked at 300 ° C. for 30 minutes and the ultraviolet irradiation time was 240 seconds. A seamless tubular body was prepared. At this time, the average value of the surface water contact angle in the entire peripheral area of the end portion of the cylindrical core body was 50 °, and the average value of the surface water contact angle in the entire peripheral area of the central portion was 120 °.

  However, after applying the polyimide precursor solution, a repelling phenomenon occurred in the central portion of the cylindrical core, so that a polyimide seamless tubular product could not be produced.

(Comparative Example 3)
In the production of the seamless tubular body of Example 1, it was made of polyimide in the same manner as in Example 1 except that baking of the silicone resin composition applied to the cylindrical core body was performed at 300 ° C. for 45 minutes and the ultraviolet irradiation time was 210 seconds. A seamless tubular body was prepared. At this time, the average value of the surface water contact angle in the entire peripheral area of the end portion of the cylindrical core body was 50 °, and the average value of the surface water contact angle in the entire peripheral area of the central portion was 110 °.

  However, when heating and curing were performed in the same manner as in Example 1, splitting occurred at the boundary between the end portion and the central portion of the cylindrical core, and a good polyimide seamless tubular product could not be obtained. .

(Comparative Example 4)
In the production of the seamless tubular body of Example 1, baking of the silicone resin composition applied to the cylindrical core body was performed at 300 ° C. for 1 hour, and ultraviolet irradiation was performed at the center of the cylindrical core body (in a range other than 30 mm from both ends). A seamless tubular body made of polyimide was prepared in the same manner as in Example 1 except that the process was performed for 120 seconds. At this time, the average value of the surface water contact angle in the entire peripheral area of the end portion of the cylindrical core body was 100 °, and the average value of the surface water contact angle in the entire peripheral area of the central portion was 80 °.

  The polyimide resin film obtained has a length of 270 mm, a contraction rate in the core axis direction with respect to the coating film of 10%, no repellency, no flow phenomenon, good film formability, and close contact with the core surface However, the film thickness displacement in the core axis direction was 14 μm, and the volume resistance displacement in the core axis direction was 1.0 digit. A polyimide seamless tubular product was obtained by cutting the both ends of this by 20 mm.

  Using this polyimide seamless tubular material, a transfer roll was prepared in the same manner as in Example 1, and evaluation was performed as a bias roll with the same image forming apparatus. As a result, uneven density based on uneven transfer occurred.

(Comparative Example 5)
In the production of the seamless tubular body of Example 1, a fluorine resin (manufactured by Daikin: TC7808) was used instead of the silicone resin composition applied to the cylindrical core body, and the ultraviolet irradiation time to the core body end portion was 300 seconds. A polyimide seamless tubular body was prepared in the same manner as in Example 1 except that. At this time, the average value of the surface water contact angle in the entire peripheral area of the end portion of the cylindrical core body is 120 °, and the average value of the surface water contact angle in the entire peripheral area of the central portion is 120 °, There was no change in the contact angle.

  However, after applying the polyimide precursor solution, cissing occurred on the entire surface of the cylindrical core, and the fluororesin was fused to the resin film by heating at 300 ° C., so a polyimide seamless tubular product could not be produced. It was.

(Comparative Example 6)
The aluminum cylindrical core used in Example 1 was masked by applying three 10 mm × 10 mm adhesive tapes at equal intervals in the circumferential direction to 30 mm from both ends. A silicone-based resin composition was applied to the surface of the core body 1 and the adhesive tape was peeled off, followed by baking at 380 ° C. for 1 hour.

  At this time, the average value of the surface water contact angle in the entire peripheral area of the central part of the cylindrical core was 80 °, but the surface water contact angle of the end part was not constant in the entire peripheral area, and the masking was performed. The surface water contact angle of the part was 40 °.

  Using this cylindrical core, a polyimide seamless tubular material was molded in the same manner as in Example 1. As a result, the resulting polyimide resin film had a length of 300 mm and a contraction rate in the core axis direction with respect to the coating film. The film formation was good with no repellency or flow phenomenon, but the resin coating was difficult to separate from the core surface. Further, the film thickness displacement in the core axis direction was 8 μm, and the volume resistance value displacement in the core axis direction was 0.6 digits. Furthermore, since there is distortion of the shrinkage at the end, a polyimide seamless tubular product was obtained by cutting both ends of this 30 mm.

  Using this polyimide seamless tubular material, a transfer roll was prepared in the same manner as in Example 1, and evaluation was performed as a bias roll with the same image forming apparatus. As a result, uneven density based on uneven transfer occurred.

The above results are summarized in Table 1. The criteria for each item in Table 1 were as follows.
-Water contact angle adjustment-
○: Easily reduced by UV irradiation.
X: Not easily lowered by ultraviolet irradiation.

-Film formability-
○ ・ ・ ・ No repelling or sticking occurs × ・ ・ ・ Repelling or sticking occurs

-Image quality evaluation-
○ ・ ・ ・ No density unevenness × ・ ・ ・ Density unevenness

(A) is the schematic which showed the method of apply | coating the polyimide precursor solution in this invention to a cylindrical core. (B) is sectional drawing in the application part of the cylindrical core body as described in (A). 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention.

Explanation of symbols

1 Photosensitive drum (image carrier)
2 Intermediate transfer belt (intermediate transfer member)
DESCRIPTION OF SYMBOLS 3 Bias roll 4 Paper tray 5 Black developing device 6 Yellow developing device 7 Magenta developing device 8 Cyan developing device 9 Intermediate transfer body cleaning device 13 Peeling claw 21 Belt roll 22 Backup roll 23 Belt roll 24 Belt roll 25 Conductive roll 26 Electrode roll 31 Cleaning Blade 41 Recording Paper 42 Pickup Roll 43 Feed Roll 51 Cylindrical Core 52 Plate 53 Container 54 Polyimide Precursor Solution

Claims (8)

An application step of applying a liquid heat-resistant resin composition to the outer peripheral surface of a metal cylindrical core, and a resin coating by heating the liquid heat-resistant resin applied to the outer peripheral surface of the cylindrical core A method for producing a seamless tubular article, comprising: a curing step to perform; and a separation step of separating the resin coating from the cylindrical core,
The ratio (θ1 / θ2) between the surface water contact angle (θ1) in the entire circumference of the end portion of the cylindrical core and the surface water contact angle (θ2) in the entire circumference of the central portion of the cylindrical core is 0. A method for producing a seamless tubular product, characterized by being in the range of 5 to 0.9.   The surface water contact angle (θ1) of the entire circumference of the end portion of the cylindrical core is 50 ° or more, and the surface water contact angle (θ2) of the entire circumference of the central portion of the cylindrical core is 60 to 110 °. The method for producing a seamless tubular article according to claim 1, wherein   The method for producing a seamless tubular product according to claim 1 or 2, wherein the cylindrical core has a coating layer containing a silicone resin composition on an outer peripheral surface.   The resin film is composed mainly of polyimide, and a polyimide precursor solution is uniformly applied to the outer peripheral surface of the cylindrical core body, heated to cause an imide conversion reaction, and then separated from the cylindrical core body. It is a film, The manufacturing method of the seamless tubular product in any one of Claims 1-3 characterized by the above-mentioned.   The method for producing a seamless tubular product according to any one of claims 1 to 4, wherein the liquid heat-resistant resin composition is an aromatic polyimide precursor obtained by dispersing a conductive agent. A liquid heat-resistant resin composition is applied to the outer peripheral surface of the cylindrical core, and after the applied liquid heat-resistant resin is heated to form a resin film, the resin film is separated from the outer peripheral surface. A metallic cylindrical core used in a method for producing a seamless tubular article,
The ratio (θ1 / θ2) between the surface water contact angle (θ1) of the entire circumference of the end portion and the surface water contact angle (θ2) of the entire circumference of the central portion is in the range of 0.5 to 0.9. Characteristic cylindrical core.   A seamless tubular article manufactured by the method for producing a seamless tubular article according to claim 1. An image forming apparatus including at least a charging unit, a developing unit, a transfer unit, and a fixing unit,
An image forming apparatus using the seamless tubular article according to claim 7 as a member constituting at least one of the charging unit, the developing unit, the transfer unit, and the fixing unit.

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