JP2006055778A - Coating method for resin solution, and production methods for thermosetting-resin endless belt and thermosetting-resin fixation belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating method for a resin solution which enables the formation of an even coating film even if using a core body with a bad roundness and to provide production methods for an endless belt and a fixation belt each of a thermosetting resin, using the coating method for the resin solution. <P>SOLUTION: While making a cylindrical or columnar core body to rotate with its central axis kept horizontal, the resin solution is made to flow down from a liquid nozzle on an area to be coated with the resin solution onto the surface of the core body, and while making the resin solution to adhere, the adhered resin solution is made to be flat so that the resin solution is flatly coated on the surface of the core body. Making the resin solution adhered on the surface of the core body to be flat, is carried out by blowing air from an air nozzle against the resin solution adhered on the surface of the core body. The production methods for the endless belt and the fixation belt of the thermosetting resin, using the coating method for the resin solution, are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin solution coating method in which a resin solution is coated on a cylindrical or columnar core. The present invention also relates to a thermosetting resin endless belt used as a heat fixing member of an electrophotographic apparatus such as a copying machine or a laser printer, and a method for manufacturing a fixing belt.

  In an electrophotographic apparatus, a rotating body made of metal, plastic, or rubber is used as a fixing body for heating and fixing a toner image on a recording sheet. As the rotating body, a thin resin belt that can be deformed is used (for example, see Patent Documents 1 and 2). In this case, if there is a seam in the belt, a defect due to the seam occurs in the output image. Therefore, an endless belt without a seam is preferable. The material is particularly preferably a polyimide resin in terms of strength, dimensional stability, heat resistance, etc. (hereinafter, polyimide is abbreviated as PI).

  The PI resin is produced by applying a precursor to a metal core, drying, and heating and firing. The PI precursor is synthesized by dissolving an acid anhydride and a diamine in an aprotic polar solvent. Examples of the aprotic polar solvent include N-methylpyrrolidone, N, N-dimethylacetamide, acetamide, N, N-dimethylformamide and the like. The concentration, viscosity and the like at the time of synthesis are appropriately selected.

In order to use the PI resin belt as a fixing member, it is preferable to provide a non-adhesive layer on the belt surface for the releasability of the toner adhering to the surface. As the material of the layer, fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and the like are preferable. For non-adhesive layers, carbon powder, inorganic compound powders such as titanium oxide and barium sulfate, etc. are used to improve wear resistance, electrostatic offset, and compatibility with toner adhesion prevention oil. Materials other than resin may be included.
As the fixing belt, the PI resin layer preferably has a thickness of 25 to 200 μm, and the fluororesin layer preferably has a thickness of 5 to 50 μm.

  In order to produce an endless belt using PI resin, a PI precursor solution is applied to the inner surface of the cylindrical body and dried while rotating (for example, see Patent Document 3), or the PI precursor is applied to the inner surface of the cylindrical body. There is an inner surface coating method in which a solution is developed (see, for example, Patent Document 4). However, in the method of forming a film on the inner surface of these cylindrical bodies, it is necessary to heat-treat the PI precursor film until it can maintain strength as a tubular body, and then remove it from the cylindrical body and mount it on the outer mold. There was a problem that increased. In addition, when a fluororesin is applied to the surface, it is necessary to apply the fluororesin after it is mounted on the outer mold.

As another method for producing a PI resin endless belt, there is also a method of forming a PI resin film on the outer surface of the core body by applying a PI precursor solution to the surface of the core body by a dip coating method, drying, and heating. is there.
When the PI precursor solution has a high viscosity and the film thickness becomes too thick, the high viscosity resin solution is supplied from the liquid nozzle while rotating the core body, and the liquid nozzle is moved in the axial direction of the core body. There is also a method in which the PI precursor solution is applied to the surface of the core body by moving and sliding smoothly and spirally with a spatula together with the liquid nozzle (see, for example, Patent Document 5). This method has an advantage that even a high-viscosity PI precursor solution can be applied to a desired film thickness and can be put into the heat drying step while the core is rotated in the horizontal direction.

However, when the PI precursor solution is applied to the surface of the core body and heated, and the process of forming the PI resin film on the outer surface of the core body is repeated, the roundness in the case of the metal cylindrical core body of the core body is increased. It deteriorates and causes rotational runout at the time of application, the PI precursor solution cannot be smoothed with a spatula, and the spiral stripe pattern may not disappear.
JP-A-8-262903 Japanese Patent Application Laid-Open No. 11-133776 JP-A-57-74131 Japanese Patent Laid-Open No. 62-19437 Japanese Patent Laid-Open No. 10-69183

Accordingly, an object of the present invention is to solve the conventional problems and achieve the following object. That is, an object of the present invention is to provide a resin solution coating method capable of forming a flat coating film even when a core having poor roundness is used.
Another object of the present invention is to provide a method for producing a thermosetting resin endless belt and a fixing belt using the resin solution coating method.

As a result of studies to solve the above problems, it was found that the resin solution coating film can be flattened by blowing air onto the resin solution adhered to the surface of the core, and the present invention has been completed.
That is, the present invention
<1> While rotating the cylindrical or columnar core with the central axis thereof being horizontal, the resin solution is allowed to flow down from the liquid nozzle to the region where the resin solution on the surface of the core is to be applied. A method of applying a resin solution by planarizing the adhered resin solution while applying the solution while applying the resin solution to the surface of the core, wherein the resin solution adhered to the surface of the core is The flattening is performed by blowing air from an air nozzle onto the resin solution adhering to the surface of the core body.

<2> A liquid nozzle having a slit-shaped opening having a width that allows the resin solution to flow down in a region where the resin solution on the surface of the core is to be applied. A plurality of dot-like liquid nozzles or one dot-like liquid nozzle arranged at a position where the resin solution can be allowed to flow down in a region where the resin solution is to be applied, and the air nozzle is An air nozzle having a slit-like opening having a width that allows air to be blown over the entire attached resin solution, or a plurality of point-like air nozzles disposed at positions where air can be blown over the attached resin solution, or <1> The method for applying a resin solution according to <1>, wherein the method is one point-like air nozzle.

<3> The liquid nozzle is one point-like liquid nozzle, and the liquid nozzle and the core are relatively moved in a horizontal direction from one end of the region to which the resin solution is to be applied to the other end. <2> The method for applying a resin solution according to <2>.
<4> The method for applying a resin solution according to <3>, wherein the air nozzle is one dot-like air nozzle, and the air nozzle is moved following the liquid nozzle.

<5> The method for applying a resin solution according to any one of <1> to <4>, wherein the resin is a polyimide precursor.
<6> The method for applying a resin solution according to any one of <1> to <5>, wherein the air is hot air of 50 ° C. or higher.

<7> Thermosetting resin precursor coating is formed by applying a thermosetting resin precursor solution to a cylindrical or columnar core and drying to form a thermosetting resin precursor coating on the core. Separating the step, the thermosetting resin film forming step of forming the thermosetting resin film by heating and baking the thermosetting resin precursor coating film, and the core and the thermosetting resin film A process for producing a thermosetting resin endless belt, wherein the application of the thermosetting resin precursor solution is a method of applying a resin solution according to any one of <1> to <6> This is a method for producing a thermosetting resin endless belt.
<8> The method for producing a thermosetting resin endless belt according to <7>, wherein the thermosetting resin is polyimide.

<9> A thermosetting resin precursor coating that forms a thermosetting resin precursor coating on the core by applying a thermosetting resin precursor solution to a cylindrical or columnar core and drying it. And a fluororesin coating film forming step of forming a fluororesin coating film on the thermosetting resin precursor coating surface by applying a fluororesin solution to the thermosetting resin precursor coating film surface and drying the coating. A thermosetting resin that forms a thermosetting resin film with the fluororesin coating film formed on the surface by heating and baking the thermosetting resin precursor coating film with the fluororesin coating film formed on the surface. A method for producing a thermosetting resin fixing belt, comprising: a film forming step; and a separation step of separating the core and the thermosetting resin film, wherein the application of the thermosetting resin precursor solution comprises: <1> to <6> are performed by the resin solution coating method according to any one of the above. A method for producing a thermosetting resin fixing belt.
<10> The method for producing a thermosetting resin fixing belt according to <9>, wherein the thermosetting resin is a polyimide precursor.

  According to the present invention, it is possible to provide a resin solution coating method capable of forming a flat coating film even when a core having poor roundness is used. In addition, according to the present invention, there can be provided a method for producing a thermosetting resin endless belt and a fixing belt using the resin solution coating method.

<Application method of resin solution>
In the resin solution coating method of the present invention, the resin solution is applied to a region where the resin solution on the surface of the core body is to be applied while rotating the cylindrical or columnar core body with its central axis being horizontal. A resin solution coating method in which a resin solution is applied to the surface of the core body by flattening the attached resin solution while flowing down from a nozzle and attaching the resin solution, the core body comprising: The resin solution adhering to the surface is flattened by blowing air from an air nozzle onto the resin solution adhering to the core surface.
Hereinafter, the following first to third embodiments, which are preferred embodiments, of the resin solution coating method of the present invention will be described with reference to the drawings. Note that members having substantially the same functions are given the same reference numerals throughout the drawings, and detailed descriptions thereof are omitted.

A first embodiment of the resin solution coating method of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic perspective view for explaining the first embodiment of the resin solution coating method of the present invention, and FIG. 2 explains the first embodiment of the resin solution coating method of the present invention. It is a schematic sectional drawing for.
In FIG. 1, a cylindrical core body 10 that is an object to be coated is sandwiched between holding members 12. Although not shown, the core body 10 is disposed via a holding member 12 on a pedestal having an arm that supports the core body 10 so as to be horizontally rotatable (arrow A). Although not shown, the core body 10 is connected to the driving means (rotating means) for rotating the core body 10 via the holding member 12.

  Around the core 10, a liquid nozzle 18 which is a point liquid nozzle for flowing a polyimide resin precursor solution (PI precursor solution) 14 as a resin solution to adhere the PI precursor solution 14 to the core 10. And a container 20 for supplying the PI precursor solution 14 to the liquid nozzle 18. As the container 20, for example, an apparatus using a meniscus cylinder, a screw, or the like is applied. The liquid nozzle 18 and the container 20 may be connected by a connecting pipe, and the nozzle 18 and the container 20 may be separated and placed separately, or the liquid nozzle 18 and the container 20 may be configured integrally. Good.

  When the viscosity of the PI precursor solution 14 is high, the PI precursor solution 14 does not naturally flow down from the liquid nozzle 18 by gravity alone. Therefore, it is also effective to extrude from the container 20 with air pressure or a pump. The distance between the liquid nozzle 18 and the core body 10 may be arbitrary, but is preferably about 10 to 100 mm so that the falling liquid is not interrupted. If the liquid breaks off, bubbles may be involved.

In the first embodiment of the resin solution coating method of the present invention, an air nozzle 22 that is a point-like air nozzle for smoothing the PI precursor solution 14 attached to the core body 10 is disposed. Air is supplied to the air nozzle 22 via an air hose 24 from air supply means (not shown).
In the present invention, the dot liquid nozzle refers to a circular nozzle having a diameter of 5 mm or less. On the other hand, the point-like air nozzle refers to a nozzle having a size that fits in a circle having a diameter of 3 mm or less, and may be any shape such as a circle, an ellipse, or a square.

  In the first embodiment of the resin solution coating method of the present invention, as shown in FIG. 2, first, the PI precursor solution 14 is caused to flow down from the liquid nozzle 18 while rotating the core body 10 in the direction of arrow A. Then, the PI precursor solution 14 is attached to the core body 10. At the same time, air is blown from the air nozzle 22 to the PI precursor solution 14 attached to the core body 10, and the PI precursor solution 14 attached to the core body 10 is flattened.

  Further, as the PI precursor solution 14 adheres to the core body 10 and becomes flat, the liquid nozzle 14 and the core body 10 are relatively applied from one end to the other end of the region where the PI precursor solution 14 is to be applied. The PI precursor solution 14 is adhered by moving in the horizontal direction (arrow B), and the air nozzle 22 is also moved following the liquid nozzle 18. Although not shown, this configuration may be a configuration in which the liquid nozzle 18 and the air nozzle 22 are moved, a configuration in which the core body 10 is moved, and can be configured by a known technique. Thereby, it can be made to adhere to the area | region which is going to apply | coat the PI precursor solution 14, and also the PI precursor solution 14 which adhered can be planarized. In particular, even when the roundness of the core 10 is poor, a flattened coating film of the PI precursor solution 14 can be obtained, and the generation of spiral streaks can be prevented as much as possible.

  In addition, when it is going to form the coating film of the PI precursor solution 14 on the whole surface of the core body 10, the coating film of the PI precursor solution 14 is hard to be formed over the whole surface of the core body 10, and there are some on both ends. An uncoated part is left. Therefore, although not shown in the drawings, if a cylindrical body having the same outer diameter as the outer diameter of the core body 10 is attached to both ends of the core body 10 and applied to the cylindrical body, PI is applied over the entire surface of the core body 10. A coating film of the precursor solution 14 can also be formed. In that case, the cylindrical body may be removed after the PI precursor solution 14 is applied, and the coating film may be washed.

The core body 10 used in the present invention may be cylindrical or columnar, but may be a cylindrical core body in terms of workability (light weight, etc.) and cost (material cost of the core body). preferable.
The cylindrical core body 10 has a thickness of 0.5 to 3.0 mm, preferably a diameter of 10 to 50 mm, and a thickness of 1.0 to 3.0 mm. More preferably, the diameter is 20 to 50 mm.
The core 10 is preferably made of a metal such as aluminum, nickel or stainless steel, but aluminum is particularly preferred from the viewpoint of a high coefficient of thermal expansion. The surface of the core may be plated with chrome or nickel, or covered with a fluororesin or silicone resin. It is preferable to apply a release agent to the surface of the core so that the resin film does not adhere.

  On the other hand, the core 10 removes residual solvent or water generated from the thermosetting resin during the heating reaction during drying in the method for producing a thermosetting resin endless belt or thermosetting resin fixing belt described later. If this is not possible, it may be unavoidable that the thermosetting resin film swells. This is particularly noticeable when the film thickness of the thermosetting resin film exceeds 50 μm. In this case, it is effective to roughen the surface of the core body 10. That is, the residual solvent or water vapor generated from the thermosetting resin film can be discharged to the outside through a slight gap formed between the core and the thermosetting resin film, and no swelling occurs. The roughness of the roughening is preferably about 0.2 to 2 μm in Ra.

  As a method for roughening the surface of the core body 10, there are methods such as blasting, cutting, sandpapering and the like. In particular, in order to make the inner surface of the thermosetting resin belt into a spherical convex shape, the surface of the core body 10 is preferably subjected to a blasting process using spherical particles. Blasting is a method of forming indentations by spraying particles made of glass, alumina, zirconia or the like having a diameter of about 0.1 to 1 mm onto a core body with compressed air. When amorphous alumina particles (for example, general abrasive particles) are used as the blast particles, the rough surface shape of the core body also becomes irregular, and particularly, sharp projections and depressions are easily formed. In some cases, an acute-angled protrusion or depression is also formed on the inner surface of the thermosetting resin endless belt or the thermosetting resin fixing belt.

In addition, in 1st embodiment of the coating method of the resin solution of this invention demonstrated using FIG.1 and FIG.2, although the polyimide precursor was used as said resin, as said resin, it is not restricted to a polyimide precursor, Any resin can be used, and examples of these resins include polyamide imide, polycarbonate, polyester, and polyamide resins in addition to the polyimide precursor. Among these resins, in particular, when a polyimide resin film is formed as described later using a polyimide precursor, drying and baking treatment is performed at a relatively higher temperature condition than other resins, and this is repeated. The roundness of the core is likely to deteriorate. For this reason, when applying the PI precursor solution 14 as a resin solution, the effect of this invention is exhibited more and is especially preferable. The PI precursor solution 14 preferably has a concentration of 10 to 25% by mass. The viscosity in this case is about 10 to 1000 Pa · s.
Examples of the solvent in the resin solution include water, organic solvents such as N-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc), leveling agents such as silicone, and the like.

The wind speed of the air blown from the air nozzle 18 is not particularly limited, but is preferably 20 to 320 m / s, more preferably 100 to 300 m / s in that the resin solution attached to the core body 10 can be further flattened. More preferably.
The distance between the air nozzle 18 and the core body 10 is not particularly limited, but is preferably 5 to 50 mm, more preferably 10 to 30 mm in that the resin solution attached to the core body 10 can be further flattened. preferable.

The temperature of the air blown from the air nozzle 18 is preferably hot air of 50 ° C. or higher, and preferably 50 to 200 ° C. in that the resin solution attached to the core body 10 can be further flattened. It is preferable that it is -150 degreeC.
Further, when the resin solution is the PI precursor solution 14, the temperature of the air is preferably 50 to 80 ° C., particularly in that the PI precursor solution 14 attached to the core body 10 can be further flattened. More preferably, it is 50-60 degreeC.

  The rotational speed of the core body 14 is preferably 20 to 200 rpm. On the other hand, the coating speed V is expressed by the following equation: V = f / (t · k · π) where k is the outer diameter of the core body 14, f is the flow rate of the resin solution, and t is the desired wet film thickness. It is preferable to adjust to the value represented.

A second embodiment of the resin solution coating method of the present invention will be described with reference to FIG. FIG. 3 is a schematic perspective view for explaining a second embodiment of the resin solution coating method of the present invention.
In the second embodiment of the resin solution coating method of the present invention, an air nozzle 22 that is a dot-like air nozzle to which air is supplied from an air supply means (not shown) via an air hose 24 is not shown. Air is supplied from an air supply means through an air hose 24 ′, except that the slit-like air nozzle 26 (with a width that allows air to be blown over the attached PI precursor solution 14) is changed. It is the structure similar to 1st embodiment of the coating method of the resin solution of this invention.

The second embodiment of the resin solution coating method of the present invention is a first embodiment of the resin solution coating method of the present invention, except that the slit-like air nozzle 26 is fixed without being moved following the liquid nozzle 18. In the same manner as in the first embodiment, the PI precursor solution 14 is attached to the surface of the core body 10 and flattened.
The shape of the slit-shaped air nozzle 26 is not particularly limited as long as the slit-shaped air nozzle 26 has a slit-shaped opening having a coating width that allows air to be sprayed onto a region where the PI precursor solution 14 is to be coated.

  FIG. 3 shows an air nozzle having a slit-like opening having a width that allows air to be blown over the attached PI precursor solution 14 as the slit-like air nozzle 26. As an alternative, an air nozzle in which a plurality of dot-like air nozzles are incorporated in a block and arranged at a position where air can be blown over the attached PI precursor solution 14 may be used. According to the second embodiment of the resin solution coating method of the present invention, a flattened coating film of the PI precursor solution 14 can be obtained in a short time even when the roundness of the core body 10 is poor, and the spiral is obtained. It is possible to prevent the generation of the streak as much as possible.

A third embodiment of the resin solution coating method of the present invention will be described with reference to FIG. FIG. 4 is a schematic perspective view for explaining a third embodiment of the resin solution coating method of the present invention.
The configuration of the third embodiment of the resin solution coating method of the present invention is such that the liquid nozzle 18 and the container 20 incorporate a plurality of liquid nozzles into a block and apply the PI precursor solution 14 on the core surface. The configuration is the same as that of the second embodiment of the resin solution coating method of the present invention except that the liquid nozzle group 28 is arranged at a position where the PI precursor solution 14 can be attached to the region. .

The third embodiment of the resin solution coating method of the present invention is the same as the second embodiment of the resin solution coating method of the present invention except that the liquid nozzle group 28 is fixed without moving. The PI precursor solution 14 is attached to the surface of the body 10 and flattened.
The shape of each nozzle in the liquid nozzle group 28 is the same as the shape of the liquid nozzle 18.

  In FIG. 4, a slit-like air nozzle 26 is described as an air nozzle. However, as the air nozzle, a plurality of air nozzles are incorporated in a block so that the PI precursor solution 14 is attached. The air nozzle group may be arranged at a position corresponding to the area to be performed. According to the third embodiment of the resin solution coating method of the present invention, the flattened coating film of the PI precursor solution 14 can be obtained in a shorter time, particularly when the roundness of the core 10 is poor. Spiral streaks can be prevented as much as possible.

<Method for producing thermosetting resin endless belt>
The method for producing the thermosetting resin endless belt according to the present invention comprises applying a thermosetting resin precursor solution to a cylindrical or columnar core and drying it, and applying the thermosetting resin precursor coating to the core. Forming a thermosetting resin precursor coating film, heating and baking the thermosetting resin precursor coating film to form a thermosetting resin film, and the core body And a separation step of separating the thermosetting resin film from the thermosetting resin endless belt, and the application of the thermosetting resin is performed by the application method of the resin solution of the present invention described above. It is performed.

The thermosetting resin is not particularly limited as long as it is thermosetting, and examples thereof include resins of polyimide, polyamideimide, polycarbonate, polyester, and polyamide. Among these thermosetting resins, in particular, when polyimide is used, when a polyimide resin film is formed as will be described later, drying and baking treatment is performed at a relatively higher temperature condition than other resins, and this is repeated. If done, the roundness of the core tends to deteriorate. For this reason, when applying a polyimide as a thermosetting resin, the effect of this invention is exhibited more and it is especially preferable.
Hereinafter, a method for producing a thermosetting resin (PI resin) endless belt when the thermosetting resin is the most preferable polyimide will be described.

(PI precursor coating film forming process)
The PI precursor coating film is formed by applying the PI precursor solution 14 on the core body 10 and drying it by the above-described method for applying the resin solution of the present invention. In this case, the drying is preferably performed at a temperature of 0 to 150 ° C. and a drying time of 30 to 200 minutes. At that time, the aprotic polar solvent, which is a solvent, is very slow to dry. Therefore, when the temperature is increased to accelerate drying, the viscosity of the PI precursor solution decreases, and the PI precursor coating film is affected by gravity. , Easy to sag before drying. In that case, it is good to dry the apply | coated core body, making an axial direction horizontal and rotating at about 10-60 rpm. In that case, it is preferable to continue rotating from the spin coating process.

At the time after drying, about 10 to 40% of the initial content of the aprotic polar solvent remains in the PI precursor coating film, and the coating film still has flexibility. Therefore, the coating film is not removable from the core and does not retain the strength as a tubular product, but when the coating is dried to the extent that it can retain the strength as a tubular product, Adhesion decreases.
Since the PI precursor coating film shrinks upon drying, when the coating film is formed leaving some uncoated portions at both ends of the core body, the uncoated surface (exposed portion of the core body surface) expands and the core Even when a coating film is formed over the entire surface of the body, an exposed portion of the core surface is generated at one or both ends.

(PI resin film formation process)
The PI precursor coating film obtained in the PI precursor coating film forming step is preferably heated and baked at a temperature of 350 to 450 ° C. for a time of 20 to 60 minutes to cause the PI precursor to undergo a condensation reaction. A resin film is formed. In that case, when the fluororesin powder mentioned later is laminated | stacked, fluororesin powder is melt-fired and becomes a fluororesin layer. If the solvent remains in the PI precursor coating film, the coating film may be swollen. Therefore, it is preferable to completely remove the residual solvent until the temperature is reached. It is preferable to raise the temperature stepwise or slowly.

  When the core body 10 is cooled to room temperature after heating and baking, a PI resin (thermosetting resin) endless belt is formed and can be taken out from the core body 10. The obtained PI resin endless belt is subjected to cutting processing for aligning the length of the end portion, polishing processing for adjusting the surface roughness, and the like, as necessary.

<Method for producing thermosetting resin fixing belt>
The manufacturing method of the thermosetting resin fixing belt of the present invention is the manufacturing method of the thermosetting resin endless belt of the present invention, further by the following fluororesin coating film forming step after the thermosetting resin precursor coating film forming step. Then, a fluororesin coating film is formed, followed by a thermosetting resin film forming step and a separation step, and a fixing belt in which a fluororesin layer is laminated on the thermosetting resin film is obtained. By laminating the fluororesin layer, the toner releasability is improved and it is suitably used as a fixing belt.

(Fluorine resin coating film forming process)
In this step, when the center axis of the core body 10 is made vertical, as shown in FIG. 5, there is an end portion of the PI precursor coating 38 on the lower end side and an exposed portion of the surface of the core body 10. For example, after the coating treatment 40 is applied to the portion, the dispersion of the fluororesin is dip coated with the core body 10 vertical.

  Next, as shown in FIG. 6, the core 10 is made vertical with the side subjected to the coating treatment 40 facing down, and immersed in a coating tank 44 containing the fluororesin dispersion 42, and then pulled up. A coating 46 of the dispersion is applied. An annular blower 48 is attached to the upper part of the coating tank 44. The fluororesin dispersion may be stored in the coating tank 44, but may be supplied from the lower part of the coating tank 44, overflowed from the upper part, recovered, and circulated by a pump.

  In that case, as shown in FIG. 7, an external tank 50 having a capacity equal to or larger than the volume of the core body 10 is provided outside the coating tank 44, and the fluororesin dispersion overflowed from the upper part of the coating tank 44 is received and stored. Supplying from the external tank 50 to the coating tank 44 by the pump 52 to circulate the fluororesin dispersion can reduce the total amount of the expensive fluororesin dispersion rather than providing another external paint tank for circulation. There is also an advantage that foaming is less likely to occur due to the fluororesin dispersion overflowing from the upper part of the coating tank 44. It is also preferable to add a filter 54, a viscometer, a diluting liquid adding device or the like to the circulation path.

  Here, as the fluororesin dispersion, the particle diameter of the fluororesin powder is preferably 1 to 20 μm, the concentration of the dispersion is preferably 10 to 70% by mass, and the viscosity is preferably about 0.1 to 1 Pa · s. As the solvent for the fluororesin dispersion, water, lower alcohols such as ethanol and butanol, glycols such as ethylene glycol, and esters thereof may be used in combination. When the concentration of the fluororesin dispersion increases due to evaporation of the solvent, it may be adjusted by adding a lower alcohol or the like. In addition, a surfactant, a viscosity modifier and the like may be added to the fluororesin dispersion.

  Before putting the fluororesin dispersion into the coating tank, it is preferable to remove bubbles from the fluororesin dispersion by defoaming. This is because if the surfactant is added, the fluororesin dispersion tends to foam, and if there are bubbles in the liquid, the coating film will be defective. As the defoaming method, there are methods such as depressurization, centrifugal separation, filtration, ultrasonic application and the like in addition to standing. Water has a solubility of about 1.19% by volume of nitrogen and about 0.64% by volume of oxygen at 20 ° C., and gases are dissolved in the fluororesin dispersion, but these dissolved gases are also reduced by reducing the pressure. It is preferable to keep it.

  The pulling speed of the core 10 from the fluororesin dispersion is about 50 to 500 mm / min, although it depends on the desired film thickness.

  At the time of pulling up, an air flow is applied to the coating film of the fluororesin dispersion by the annular blower 48 to promote the drying of the solvent, but the air flow applied to the coating film is more uniform in the circumferential direction than from one direction. It is better to apply it in a ring shape. Examples of such a blower include those described in Japanese Patent No. 2844784 and Japanese Patent No. 2629417.

  After application of the fluororesin dispersion, the solvent is dried from the coating film by being placed between room temperature and 100 ° C. for 5 to 20 minutes. Before and after drying, the previously formed coating treatment 40 is removed.

<Example 1>
As a PI precursor solution, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine were synthesized in N-methylpyrrolidone and had a solid concentration of 18% (mass%, The same applies hereinafter), and a PI precursor solution having a viscosity of about 20 Pa · s was prepared.

  An element tube having an outer diameter of 70 mm and a length of 400 mm was heated at 350 ° C. for 10 minutes and allowed to cool naturally, and then an aluminum cylinder having an outer diameter of 68 mm was prepared by cutting the surface. The roundness is 10 μm. Next, the surface is roughened to Ra 0.8 μm by blasting with spherical alumina particles, and then a silicone mold release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the surface, and then at 300 ° C. for 1 hour. The core body 10 was obtained by baking.

  Next, as shown in FIG. 3, the axial direction of the core 10 was horizontal and rotated at 120 rpm. The PI precursor solution 14 is applied to the core body 10 at 40 g / min from the liquid nozzle 18. The slit-like air nozzle 26, which is an air blowing member, is a member having a slit length of 400 mm and a slit width of 0.15 mm, and air at a temperature of 50 ° C. was blown at a blowing air speed of 100 m / sec. The air consumption is about 400 L / min. By blowing air onto the PI precursor solution 14 under these conditions, the PI precursor solution is uniformly spread by the air. Next, the liquid nozzle 18 was applied by moving from one end of the core body 10 to the other end at a speed of 180 mm / min. Under this condition, the liquid nozzle 18 moves by 1.5 mm while the core body 10 makes one rotation. When the PI precursor solution 14 was applied, uncoated portions of 5 mm each were provided at both ends of the core body 10.

  Further, the core body 10 coated with the PI precursor solution 14 was placed in a drying furnace at 100 ° C. while rotating at 20 rpm. When taken out after 60 minutes, a PI precursor film having a thickness of about 150 μm was formed, and the residual solvent was about 40%. In this state, the PI precursor coating film could not be removed from the core body 10 yet. Further, there was a gap between the end portion of the PI precursor coating film and the core 10 due to slight shrinkage of the end portion of the PI precursor coating film.

On the other hand, a PFA water-based paint (trade name: 710CL, manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd., concentration 60%, viscosity 400 mPa · s) and water as a solvent include ethanol and t-butanol as shown in FIG. In an application tank 44 having an inner diameter of 90 mm and a height of 480 mm. An annular blower 48 was attached to the upper part of the coating tank 44.
In the coating tank 44, the core body 10 was immersed with the PI precursor coating 38 on the lower side, and the upper PI precursor coating 38 was left by 5 mm. Subsequently, the core body 10 was pulled up at a speed of 0.2 m / min while applying an air flow to form a PFA coating film.

After completion of the pulling, the film was dried at 80 ° C. for 10 minutes.
As the final heating and baking step, the core 10 on which the PFA coating film is formed is heated at 150 ° C. for 20 minutes, 220 ° C. for 20 minutes, and 380 ° C. for 30 minutes to form a PI resin film, and the PFA coating film Was baked. After cooling to room temperature, the PI resin film was removed from the core, and an endless (fixing) belt having a 30 μm thick PFA layer on a 75 μm thick PI resin endless belt could be obtained. Further, the inner surface of the PI resin was a rough surface of Ra 0.8 μm, and the shape thereof was spherical and convex.

The obtained endless (fixing) belt was used as a fixing belt. Specifically, when the obtained endless (fixing) belt was mounted on a fixing device (a fixing device described in JP-A-8-262903) in which a pressure pad slides on its inner surface, a test was performed. The frictional force was small and there was no hindrance to the rotation of the fixing belt. Further, no sliding noise was generated.
Further, when the endless (fixing) belt described above is repeatedly produced, the roundness of the core 10 gradually deteriorates. When the roundness is repeated about 50 times, the roundness becomes about 100 μm. When the endless (fixing) belt obtained by using the core body 10 having a thickness of 100 μm was mounted on the above-described fixing device and tested, its frictional force was small, and there was no hindrance to the rotation of the fixing belt. . Further, no sliding noise was generated.

<Comparative Example 1>
In the spin coating process of Example 1, a spatula (SUS304, thickness 0.2 mm) was pressed against the PI precursor solution 14 applied to the core body 10 instead of blowing air with the slit-like air nozzle 26. Except this, an endless (fixing) belt was produced in the same manner as in Example 1. When the obtained endless (fixing) belt was mounted on the fixing device in the same manner as in Example 1 and tested, the frictional force was small and there was no hindrance to rotation of the fixing belt. Further, no sliding noise was generated.

  However, when the above-described production of the endless (fixing) belt was repeated, the roundness of the core body 10 gradually deteriorated, and when it was repeated about 50 times, the roundness became about 100 μm. Using this core body 10 having a roundness of about 100 μm, an endless (fixing) belt was produced in the same manner. When the PI precursor solution 14 was first applied to the core body 10, rotational runout was caused. The spatula for smoothing the PI precursor solution on the surface of the body 10 resonated with the rotational shake, and the PI precursor solution was applied to the unevenness, resulting in a spiral stripe pattern. Further, when the obtained endless (fixing) belt was mounted on the above-described fixing device and tested, the frictional force increased and sliding noise was generated.

It is a schematic perspective view for demonstrating 1st embodiment of the coating method of the resin solution of this invention. It is a schematic sectional drawing for demonstrating 1st embodiment of the coating method of the resin solution of this invention. It is a schematic perspective view for demonstrating 2nd embodiment of the coating method of the resin solution of this invention. It is a schematic perspective view for demonstrating 3rd embodiment of the coating method of the resin solution of this invention. It is a schematic block diagram which shows a mode that the clothing process was performed to the core body 10 in the manufacturing method of the fixing belt of this invention. It is a schematic block diagram which shows the coating device of the fluororesin dispersion solution in the manufacturing method of the fixing belt of this invention. It is a schematic block diagram which shows the other coating apparatus of the fluororesin dispersion solution in the manufacturing method of the fixing belt of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Core body 12 Holding member 14 PI precursor solution 18 Liquid nozzle 20 Container 22 Air nozzle 24, 24 'Air hose 26 Slit-like air nozzle 28 Liquid nozzle group 38 Polyimide resin precursor coating film 40 Coating process 42 Fluororesin dispersion liquid 44 coating tank 46 coating 48 annular blower 50 external tank 52 pump 54 filter

Claims (3)

While rotating the cylindrical or columnar core with the central axis thereof being horizontal, the resin solution is allowed to flow from the liquid nozzle to the region where the resin solution on the surface of the core is to be applied, and the resin solution is attached. A resin solution coating method for planarizing the adhered resin solution by applying the resin solution to the surface of the core body,
A resin solution coating method, wherein the resin solution adhering to the surface of the core is flattened by blowing air from an air nozzle onto the resin solution adhering to the surface of the core. Applying a thermosetting resin precursor solution to a cylindrical or columnar core and drying, a thermosetting resin precursor coating film forming step for forming a thermosetting resin precursor coating film on the core; and
A thermosetting resin film forming step of forming a thermosetting resin film by heating and baking the thermosetting resin precursor coating;
A separation step of separating the core and the thermosetting resin film;
A thermosetting resin endless belt manufacturing method comprising:
2. The method for producing a thermosetting resin endless belt, wherein the thermosetting resin precursor solution is applied by the resin solution applying method according to claim 1. A thermosetting resin precursor coating film forming step of applying a thermosetting resin precursor solution to a cylindrical or columnar core body and drying, and forming the thermosetting resin precursor coating film on the core body; ,
A fluororesin coating film forming step of applying a fluororesin solution to the thermosetting resin precursor coating surface and drying, and forming a fluororesin coating film on the thermosetting resin precursor coating surface;
A thermosetting resin film in which the thermosetting resin precursor film with the fluororesin coating film formed on the surface is heated and baked to form a thermosetting resin film with the fluororesin coating film formed on the surface. Forming process;
A separation step of separating the core and the thermosetting resin film;
A method for producing a thermosetting resin fixing belt having
The method for producing a thermosetting resin fixing belt, wherein the application of the thermosetting resin precursor solution is performed by the method for applying a resin solution according to claim 1.

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