JP2007125491A - Coater and manufacturing method of endless belt using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coater allowing uniform coating of a coating liquid on a core material without unevenness even using a coating liquid, specifically a film-forming resin, being liable to deterioration on coming into contact with air, and a manufacturing method of an endless belt for manufacturing the belt by using the coater. <P>SOLUTION: In the coater having an annular coating vessel 7 for storing a coating liquid 2 and a ring member 5, a disc-shaped cover 10, or a lid member, covering the area from the outer periphery of the ring member 5 to the upper edge of the coating vessel 7 is attached. The inside space of the coating vessel 7 covered with the cover 10, more specifically the space surrounded by the liquid surface of the coating liquid 2, the inside wall of the coating vessel 7 and the cover 10, is filled with an inert gas supplied from an inert gas injection tube 18. The arrangement avoids contact of the coating liquid 2 with air. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention uses, for example, a coating-forming resin coating liquid that is easily affected by oxygen and moisture in the air, and can apply the coating liquid uniformly on the core, and the coating apparatus. The present invention relates to a method for producing an endless belt used. The endless belt is particularly preferably used as an intermediate transfer belt of an image forming apparatus using an electrophotographic system such as a copying machine or a printer.

  In an image forming apparatus, a belt made of a thin plastic film may be used in order to reduce the size / performance of a photosensitive member, a charging member, a transfer member, and a fixing member. In that case, if there is a seam in the belt, a trace of the seam is generated in the output image. Therefore, an endless belt without a seam is preferable. As a material for the endless belt, a polyimide resin or a polyamideimide resin is preferable in terms of strength, dimensional stability, heat resistance, and the like. Hereinafter, polyimide is abbreviated as PI, and polyamideimide is abbreviated as PAI.

  In order to produce an endless belt with PI resin, there are known a centrifugal molding method in which a PI precursor solution is applied to the inner surface of a cylindrical body and dried while rotating, and an inner surface coating method in which the PI precursor solution is spread on the inner surface of the cylindrical body. However, these methods of forming a film on the inner surface of the cylindrical body have a disadvantage in that it is necessary to remove the coating from the cylindrical body and place it on the core body when the PI precursor is heated, which increases the number of steps.

  As another PI resin endless belt manufacturing method, there is a method in which a PI precursor solution is applied to the surface of the core body by a dip coating method, dried, heated and reacted, and then the PI resin film is peeled off from the core body. . This method has the advantage that the same core is used consistently from the coating film forming process by coating to the film forming process for heating reaction, and there is an advantage that no man-hours for replacement are required, but the PI resin precursor solution is Since the viscosity is very high, the film thickness may be too thick when desired to be applied on the core by the dip coating method.

  On the other hand, there is a method of controlling the film thickness of the coating liquid by an annular body, and in this method, the thickness of the coating film is regulated by the gap between the core body and the circular hole of the annular body (Patent Document 1). reference).

  In that case, there is a method using an annular coating device in order to reduce the required amount of coating liquid. The annular coating device is provided with an annular sealing material having a hole slightly smaller than the outer diameter of the core body at the bottom of the annular coating tank, the core body is inserted through the center of the annular sealing material, and the coating liquid is accommodated in the annular coating tank. . Thereby, a coating liquid does not leak. When applying the coating liquid to the core body, another core body is connected under the core body, the core body is pushed upward from the lower part of the annular coating tank, and passed through the circular hole of the annular body, A coating film is formed on the surface. The other core may be an intermediate that does not produce a belt.

  In such an annular coating apparatus, the annular coating tank can be made smaller than the dip coating tank, so that there is an advantage that the required amount of coating liquid can be reduced.

  In the above application method, depending on the type of PI precursor solution or PAI solution, when it comes into contact with air, it is difficult to cause a condensation reaction due to the influence of oxygen or moisture, the film strength is reduced, or Deterioration may occur, such as formation of precipitates in the solution and difficulty in application. In particular, in the method of applying the solution on the outer surface of the core body, since it is exposed to air over a wide area, it is easily affected by deterioration, and the solution before application should not be exposed to air as much as possible.

  Conventionally, as described in Patent Document 2, there is also an invention in which an inert gas is sprayed when a PI precursor composition is spin-coated, but this is to prevent dents in a thick part, and the deterioration of the solution In order to prevent this, an inert gas was not allowed to flow into the solution.

JP 2002-91027 A JP-A-8-37142

  Accordingly, the present invention provides a coating apparatus that can uniformly apply a coating liquid evenly on a core even when a coating liquid (film-forming resin) that easily deteriorates when exposed to air is used. It is an object of the present invention to provide an endless belt manufacturing method for manufacturing an endless belt.

The above problem is solved by the following means. That is,
The coating apparatus of the present invention is
A coating tank for storing the coating liquid and an annular body provided with a hole having an inner diameter larger than the outer diameter of the core body to which the coating liquid is applied are immersed in the coating liquid stored in the coating tank. A coating apparatus for applying a coating liquid to the surface of the core body by allowing the core body to be vertically raised from the coating liquid and passing through the holes with the axial direction of the core body vertical.
Covering the region from the outer periphery of the annular body to the upper edge of the coating tank, comprising a lid member,
And it further comprises an inert gas injection means for injecting an inert gas into the space surrounded by the lid member, the inner wall of the coating tank and the liquid surface of the coating liquid.
It is characterized by that.

  In the coating apparatus of the present invention, the coating liquid can be applied without being exposed to air by injecting and filling an inert gas into the space surrounded by the lid member, the inner wall of the coating tank, and the liquid surface of the coating liquid. Can be done. For this reason, it becomes possible to apply | coat a coating liquid uniformly on a core body, preventing deterioration of a liquid (film forming resin solution).

  In the coating apparatus according to the aspect of the invention, it is preferable that the lid member is provided so as to cover an upper edge of the tubular body and includes a regulating member that regulates movement of the core body in the axial direction. Even when the lid member is provided so as to cover the upper edge of the annular body, since the movement of the lid member in the axial direction of the core body is restricted, the gap between the lid member and the annular body or the lid member is reduced, and the inert gas to be injected Leakage is prevented, and efficient deterioration of the coating liquid is prevented.

  On the other hand, the method for producing an endless belt according to the present invention uses the coating apparatus according to the present invention to apply a film-forming coating solution to the surface of the core body, and then performs drying, heat curing, firing, or all of A film is formed by performing a treatment, and the film is removed from the core.

  ADVANTAGE OF THE INVENTION According to this invention, even if it uses the coating liquid (film forming resin) which is easy to deteriorate by touching air, the coating device which can apply | coat a coating liquid uniformly on a core, and its use An endless belt manufacturing method for manufacturing an endless belt can be provided.

  The coating apparatus of this invention is demonstrated using drawing. In addition, what has the substantially same function is attached | subjected and demonstrated through the whole figure, and the description may be abbreviate | omitted depending on the case.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing a stop time of the coating apparatus according to the first embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing the coating apparatus according to the first embodiment of the present invention during coating. However, FIG.1 and FIG.2 shows with a partially broken sectional view, and shows only a main part, The holding | maintenance mechanism of a core body and another apparatus are abbreviate | omitted (the same also in the following figures).

  As shown in FIG. 1, the coating apparatus according to the first embodiment includes an annular application tank 7 and an annular body 5 for storing the coating liquid 2. An annular sealing material 8 having a hole slightly smaller than the outer diameter of the core body is provided at the bottom of the annular coating tank 7 to prevent the coating liquid 2 from leaking. The annular body 5 is provided with a circular hole 3 having an inner diameter larger than the outer diameter of the core body 1 that is an object to be coated.

  On the other hand, a disk-shaped cover 10 (lid member) that covers a region from the outer peripheral portion of the annular body 5 to the upper edge of the annular coating tank 7 is attached. The cover 10 has a hole that is larger than the hole diameter of the annular body and smaller than the outer diameter of the annular body, covers the upper edge of the annular body 5 and is surrounded by the inner wall of the annular coating tank 7 and the liquid surface of the coating liquid 2. Is fixedly attached to the upper edge of the annular body 5. An inert gas injection pipe 18 is connected to the side wall of the annular coating tank 7 (the side wall above the liquid surface 2).

  Such an annular coating apparatus has an advantage that a smaller amount of coating liquid is required than the dip coating method. Further, in the coating apparatus of the present invention according to the present embodiment, although not shown, the core body holding means for holding the core body 1, the first moving means for moving the holding means in the vertical direction, and / or coating. You may have the 2nd moving means to move a tank to an up-down direction.

  In order to apply the coating liquid 2 to the surface of the core body 1 using the coating apparatus according to the present embodiment, the core body 1 is passed through the annular coating tank 7 and the coating liquid 2 is added, as shown in FIG. Then, another other core body 1 ′ is installed under the core body 1, and is relatively raised from the coating liquid 2. The rising speed at that time is preferably 0.1 to 1.5 m / min.

  “Applying the coating liquid to the surface of the core” means applying to the surface of the outer peripheral surface of the core and the surface of the layer when the surface has a layer. Further, “raising the core” is a relative relationship with the liquid level during application, and includes the case of “stopping the core and lowering the coating liquid”.

  When the core body 1 is raised from the coating liquid 2, the annular body 5 is lifted together with the cover 10 due to frictional resistance due to the viscosity of the solution. Since the annular body 5 is freely movable in the horizontal direction, the frictional resistance between the core body 1 and the annular body 5 is constant in the circumferential direction, that is, between the surface of the core body 1 and the circular hole of the annular body 5. The annular body 5 moves so that the gap is uniform, and the coating film 4 having a uniform film thickness is formed on the core body 1. In this way, since the film thickness is regulated by the annular body 5, a highly viscous solution can be used, and since the coating film hangs down due to gravity at the upper end of the core body 1, the film thickness can be reduced both in the circumferential direction and in the axial direction. It can be made uniform.

  Since the film thickness of the coating film 4 is determined by the gap between the outer diameter of the core body 1 and the circular hole, the diameter of the circular hole is adjusted by the desired film thickness. On the other hand, although the annular body 5 is lifted to a certain height (in other words, the annular body 5 moves away from the liquid surface 2 in the axial direction of the core body), in the present invention, the annular body 5 and the annular body 5 are annular. At least three height regulating members 16 are attached to the cover 10 so that there are not many gaps in the coating tank 7. The height regulating member 16 is prevented from being lifted above a certain height by a fixing member 17 provided on the outer wall of the annular coating tank 7 (that is, the cover 10 is applied in the axial direction of the core body 1 with the coating liquid 2 liquid surface). To keep a certain distance from the

  Then, an inert gas is introduced from the inert gas injection pipe 18 into the internal space of the annular coating tank 7 covered with the cover 10 (the space surrounded by the coating liquid 2 liquid surface, the inner wall of the annular coating tank 7, and the cover 10). Fill and fill. As a result, the coating liquid 2 does not come into contact with air.

  Here, the inert gas refers to an inert gas with respect to the coating liquid 2 (film forming resin solution), and specific examples include nitrogen, argon, carbon dioxide, and the like.

  The height that regulates the lifting of the cover 10 (the distance away from the surface of the coating liquid 2 in the axial direction of the core body), that is, the height that regulates the lifting of the annular body 5 is preferably about 1 to 5 mm. More active gas leaks and air easily enters.

  The inert gas is preferably kept flowing little by little at all times, but when not applied, the flow rate may be reduced or stopped. If the flow rate continues to flow too much, evaporation of the solvent from the solution in the annular coating tank 7 increases and the composition changes. Therefore, in order to reduce the evaporation of the solvent from the solution in the annular coating tank 7, it is preferable to inject an inert gas having a saturated solvent vapor amount into the annular coating tank 7. In order to inject the inert gas having a saturated solvent vapor amount into the annular coating tank 7, for example, after passing through a solvent storage tank (solvent vapor amount saturation means) storing the same kind of solvent as the coating liquid. It is preferable to inject an inert gas into the annular coating tank 7.

  Specifically, for example, as shown in FIG. 3, a solvent storage tank 21 storing a solvent 20 of the same type as the coating liquid 2 is connected to an inert gas injection pipe 18, and the solvent 20 liquid surface and the solvent storage tank 21 are connected. An example is a form in which an inert gas is supplied from an inert gas supply pipe 19 through a space surrounded by an inner wall and then passed to the inert gas injection pipe 18. For example, as shown in FIG. 4, a solvent storage tank 21 storing a solvent 20 of the same type as the coating liquid 2 is connected to an inert gas injection pipe 18, and an inert gas supply pipe 19 is stored in the stored solvent 20. An embodiment is also possible in which an inert gas is supplied from and then foamed and then sent to the inert gas injection pipe 18.

  In the coating apparatus according to the present embodiment described above, an inert gas is injected into a space surrounded by the cover 10, the inner wall of the annular coating tank 7, and the coating liquid 2 liquid surface, and coating is performed without exposing the coating liquid to air. Therefore, it is possible to apply the coating liquid uniformly on the core body 1 while preventing the coating liquid 2 (film-forming resin solution) from being deteriorated.

  Further, since the cover 10 includes a regulating member that restricts the axial movement of the core body 1, the core body 1 of the cover 10 can be provided even when the cover 10 is provided so as to cover the upper edge of the annular body 5. Since the movement in the axial direction is restricted, the gap between the cover 10 and the annular body 5 is reduced, leakage of the inert gas to be injected is prevented, and efficient coating liquid deterioration is prevented.

(Second Embodiment)
FIG. 5 is a schematic configuration diagram showing when the coating apparatus according to the second embodiment of the present invention is stopped. FIG. 6 is a schematic configuration diagram showing the time of application of the coating apparatus according to the second embodiment of the present invention.

  As shown in FIG. 5, the coating apparatus according to the second embodiment is provided with a cover 11 (lid member) that covers a region from the outer peripheral portion of the annular body 5 to the upper edge of the annular coating tank 7. Specifically, the cover 11 is provided with a hole 11 </ b> A having an inner diameter slightly larger than the outer diameter of the annular body 5. The annular body 5 enters the hole 11 </ b> A and the inner wall of the annular coating tank 7 and the coating liquid 2. It is arranged so as to cover the space surrounded by the liquid surface. The cover 11 is fixedly disposed on the upper end of the side wall of the annular coating tank 7.

  Also, an arm 15 that rides on the upper surface of the cover 11 is attached to the upper edge of the annular body 5 so that the annular body 5 does not sink into the coating liquid 2.

  In the case of the coating apparatus according to this embodiment, as shown in FIG. 6, when the core body 1 is lifted from the coating liquid 2, the annular body 5 is lifted to a certain height. In this case, since the cover 11 is fixed to the annular coating tank 7, it does not lift up, and the gap between the annular body 5 and the hole 11A of the cover 11 does not change. As in the first embodiment, the upper space of the annular coating tank 7 is filled with an inert gas.

  The gap between the annular body 5 and the hole of the cover 11 is preferably about 1 to 5 mm. If this is large, air easily enters. Further, the height at which the annular body 5 is lifted is preferably about 10 to 50 mm. This height can be adjusted by the weight of the annular body 5. In addition, like the first embodiment, a height restricting member may be attached to the annular body 5 to restrict the lifting of the annular body 5.

  Even in the coating apparatus according to the present embodiment described above, an inert gas is injected into a space surrounded by the cover 11, the inner wall of the annular coating tank 7, and the coating liquid 2 liquid surface, and the coating liquid is exposed to air without being exposed. Therefore, it is possible to apply the coating liquid uniformly on the core body 1 while preventing the coating liquid 2 (film-forming resin solution) from being deteriorated.

  Note that the coating apparatus according to this embodiment is the same as that of the first embodiment except for the above description, and thus the description thereof is omitted.

  Hereinafter, each member of the coating device according to the embodiment of the present invention will be described in detail.

  The core 1 is preferably a metal cylinder such as aluminum, stainless steel, nickel, or copper. In addition, when manufacturing an endless belt as will be described later, the axial length of the core body needs to be longer than the width of the target endless belt, but there is a margin for the ineffective region generated at the end. In order to ensure, it is preferable that it is 10 to 40% longer than the width of the target endless belt. The outer diameter of the core body is adjusted to the diameter of the target endless belt, and the thickness is set to a thickness that can maintain the strength of the core body.

  Further, although not shown, a holding plate for holding the core body 1 may be attached to both ends of the core body 1. The holding plate may have an arbitrarily shaped ventilation hole, a hole through which a mandrel passes in the center, or a shaft. Moreover, you may attach components for hanging or mounting.

  Moreover, in order to prevent the film | membrane formed from adhering to the core body surface, the core body 1 is good to provide a mold release property to the surface of a core body. For this, there are methods of coating the core surface with a fluororesin or silicone resin, or applying a release agent to the core surface.

  Depending on the type of the coating liquid 2, in the production of an endless belt, which will be described later, there are solvent volatiles during heating and gas generated during reaction, and the resin film after heating partially swells due to the generated gas. May occur. This may occur particularly when a PI precursor solution is used as the coating liquid and the film thickness exceeds 50 μm.

  In order to prevent the above-described swelling, it is preferable to roughen the core surface to Ra 0.2 to 2 μm as described in JP-A-2002-160239. Examples of the roughening method include blasting, cutting, sandpaper peeling, and the like. Thereby, the gas generated from the coating film can go out through a slight gap formed between the core and the coating film, and does not swell.

  As described later, when an endless belt is further produced as the coating liquid 2, a PI precursor solution or a PAI resin solution is preferably used. Various known precursors can be used as the PI precursor and PAI resin. The concentration, viscosity, and the like of the PI precursor or PAI resin solution are appropriately selected. The solid content concentration of the solution preferably used is 10 to 40% by mass, and the viscosity is 1 to 100 Pa · s. The solvent of the coating liquid is an aprotic polar solvent such as N-methylpyrrolidone, N, N-dimethylacetamide, or acetamide, but these easily absorb moisture in the air. If the coating liquid absorbs moisture, the resin component in the coating liquid may precipitate and become cloudy, or the PI precursor or PAI resin may be hydrolyzed, so care must be taken. In addition, the PI precursor is strongly colored due to the influence of oxygen, the viscosity is changed, and the condensation reaction may be difficult to occur. In the present invention, these are prevented by injecting an inert gas into the coating tank.

  The material of the annular body 5 is preferably selected from metals and plastics that are not affected by the solvent of the coating liquid 2. The annular body 5 may have a hollow structure. The inner wall surface of the annular body 5 may be stepped or curved in addition to a linearly inclined surface (see FIG. 1) as long as the lower part immersed in the solution is wide and the upper part is narrow.

Hereinafter, the manufacturing method of the endless belt of the present invention will be described in detail.
In order to produce an endless belt using the coating apparatus of the present invention, the coating liquid for film formation is applied to the surface of the core described above, and then any one of drying, heat curing, baking, or all treatments is performed. Forming a film and removing the film from the core.

  Next, the method for producing an endless belt according to the present invention will be described in the case where a PI precursor solution or a PAI resin solution is used as the coating liquid.

In the production of an endless belt, the coating film coated with the coating liquid for coating is heated using the coating apparatus of the present invention, the solvent present in the coating film is removed, and the coating film is dried to the extent that the coating film is not deformed. . The heating conditions are preferably 90 to 170 ° C. and 20 to 60 minutes. At that time, the higher the temperature, the shorter the heating time, and the temperature may be raised stepwise or at a constant rate.
Further, when dripping occurs in the coating film during heating, it is effective to make the longitudinal direction of the core body horizontal and rotate it slowly. In that case, it is preferable to put the mandrel through the hole of the holding plate and put it in the dryer in a state of being placed on the turntable. When the film forming solution is a PAI resin solution, the film can be obtained only by drying the solvent.

  On the other hand, in the case where the film forming solution is a PI precursor solution, if the solvent is removed too much from the coating film, the coating film does not yet maintain strength, and thus cracking is likely to occur. Therefore, it is preferable to leave a certain amount of solvent (15 to 45% by mass in the PI precursor film). In the case where the film forming solution is a PI precursor solution, the PI precursor film is then heated at 250 to 450 ° C., preferably at 280 to 350 ° C. for 20 to 60 minutes to cause a condensation reaction. A film is formed. At that time, the temperature may be increased stepwise.

  The film formed as described above becomes an endless belt by peeling from the core after cooling. The endless belt may be further subjected to drilling or ribbing as necessary.

When the endless belt is used as a transfer belt or a contact charging belt, a conductive substance is dispersed in the film forming solution. Examples of the conductive material include carbon-based materials such as carbon black, carbon fiber, carbon nanotube, and graphite, metals or alloys such as copper, silver, and aluminum, tin oxide, indium oxide, antimony oxide, SnO ₂ —In ₂ O. ₃ Conductive metal oxides such as complex oxides. As described above, when the film contracts, the resistance value becomes uneven, but by preventing the contraction, the resistance value can be made uniform.

  The film thickness of the endless belt preferable for these uses is about 30 to 150 μm.

  Hereinafter, the present invention will be specifically described by way of examples. However, each example does not limit the present invention.

Example 1
A PI precursor solution was prepared from pyromellitic dianhydride and paraphenylenediamine using N, N-dimethylacetamide as a solvent (solid content concentration 20 mass%, viscosity 10 Pa · s). Carbon black (trade name: Special Black 4, manufactured by Degussa Huls Co., Ltd.) was mixed with this at 30% in terms of the solid content mass ratio, and then dispersed by a counter collision type disperser. Furthermore, a surfactant (trade name: LS009, manufactured by Enomoto Kasei Co., Ltd.) was added to a concentration of 500 ppm to obtain a film-forming resin solution.

  Separately, an aluminum cylinder having an outer diameter of 366 mm, a wall thickness of 10 mm, and a length of 450 mm was prepared, and the surface was roughened to Ra 1.0 μm by blasting with spherical alumina particles. Further, a holding plate having a thickness of 15 mm, an outer diameter that fits into the cylinder, four 100 mm diameter vent holes, and a 20 mm diameter hole in the center is made of the same aluminum material, and is fitted into the cylinder. The core was welded by TIG welding.

  A silicone release agent (trade name: Sepacoat, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the core. A polyester adhesive tape having a width of 10 mm was wound around the end of the core. This is to prevent the coating film from adhering to the end of the core.

  Next, the PI precursor solution (coating liquid 2) is applied to the surface of the core body by the annular coating apparatus (see FIGS. 1 to 2) according to the first embodiment. At this time, an aluminum annular body 5 having an outer diameter of 420 mm, an inner diameter of 367.1 mm at the smallest part of the circular hole, and a height of 50 mm is used. The inner wall of the annular body was linearly inclined, and the inclination angle with respect to the vertical line was 7 °. The upper end was formed with a 2 mm portion parallel to the core.

  Further, a hole having an inner diameter of 380 mm was formed in the center of an aluminum disk having a thickness of 1 mm and an outer diameter of 500 mm, and was attached to the upper edge of the annular body to be fixed and covered. Three height regulating members made of a wire having a thickness of 0.5 mm were attached to the outer wall at intervals of 120 °.

  On the other hand, an annular sealing material 8 made of hard polyethylene resin having a thickness of 364.5 mm and a hole having an inner diameter of 364.5 mm is attached to the bottom of an annular coating tank having an inner diameter of 460 mm, an outer diameter of 480 mm, and a height of 100 mm. I passed through. On the outside of the annular coating tank, three pins with a thickness of 3 mm were inserted at intervals of 120 ° at a position of 15 mm from the bottom surface to form a fixed member, and the height regulating member 16 was fitted. Accordingly, the annular body (and the cover) is restricted from being lifted by 2 mm or more, but the movement in the horizontal direction is not hindered.

  The solution was put in an annular coating tank, and an annular body was arranged. Next, after filling the space of the annular coating tank with about 2 l of nitrogen gas from the inert gas injection tube, it was continuously injected at a flow rate of about 10 ml per minute. The nitrogen gas was injected after the solvent vapor amount was saturated through a storage tank in which N, N-dimethylacetamide (solvent) was stored (see FIG. 3).

  Next, another core body having the same shape as the core body was placed under the core body and pushed up at 0.8 m / min to apply the PI precursor solution to the core body surface (see FIG. 2). . At that time, the annular body was lifted by 2 mm. Thereby, a coating film of the PI precursor having a wet film thickness of about 500 μm was formed on the core.

  The coated core body is heated at 80 ° C. for 20 minutes and at 130 ° C. for 20 minutes while passing a 20 mmφ stainless steel shaft through the center hole of the holding plate, placing it on a rotating table and turning it horizontally at 6 rpm. The PI precursor coating was dried. Thus, a PI precursor film having a thickness of about 150 μm was obtained. At this point, the adhesive tape at the end of the core was removed.

  Next, the core body was made vertical, the shaft was removed, it was placed on a heating table, placed in a heating furnace, and reacted by heating at 200 ° C. for 30 minutes and at 300 ° C. for 30 minutes to form a PI resin film on the surface of the core body.

  After cooling the core body at room temperature, the PI resin film was extracted from the core body while blowing air between the core body and the PI resin film to obtain an endless belt. The film thickness was uniform at 75 μm.

The obtained endless belt has a semiconductivity of about 10 ¹⁰ Ωcm when volume resistivity is measured at 100 V, and can be used as an electrophotographic transfer belt.
Furthermore, after stopping the inflow of nitrogen gas and interrupting the above-mentioned process for 24 hours, an endless belt was produced in the same manner again. However, the endless belt obtained after the interruption was of the same quality as that obtained at the beginning. It was.

(Comparative Example 1)
In Example 1, an endless belt was produced in the same manner as in Example 1 except that the annular body was not covered and nitrogen gas was not introduced. The endless belt obtained first was of the same quality as the endless belt obtained first in Example 1.

  However, after interruption for 24 hours in the same manner as in Example 1, a similar attempt was made again, and a film was formed on the surface of the solution due to the drying of the solvent, which was inappropriate for application. .

(Comparative Example 2)
In Example 1, a cover was provided on the annular body, but when nitrogen gas was not introduced, the endless belt obtained first was the same quality as the endless belt obtained first in Example 1. However, the belt produced after the interruption for 24 hours had uneven portions on the surface. In addition to the uneven thickness of the uneven portion, the volume resistivity was also uneven. This is presumably because this solution was slightly altered (hydrolyzed) due to oxygen and moisture in the air.

(Example 2)
An endless belt was obtained in the same manner as in Example 1 except that the annular coating apparatus (see FIGS. 5 to 6) according to the second embodiment was used. Specifically, in Example 1, instead of installing a cover on the annular body, the cover was attached and fixed to the upper edge of the coating tank. This cover is made of an aluminum disk having a thickness of 1 mm, an outer diameter of 500 mm, and an inner diameter of 424 mm, and the gap with the outer diameter portion of the annular body is 2 mm.

  Three arms made of SUS plates with a thickness of 1 mm were attached to the upper edge of the annular body at intervals of 120 °, and placed on a cover to prevent the annular body from sinking.

  Others are the same as in Example 1, the solution is put in the annular coating tank, the annular body is arranged, about 2 liters of nitrogen gas is injected into the space of the annular coating tank and filled, and then injected at a flow rate of about 10 ml per minute. I kept doing it. The nitrogen gas was injected after the solvent vapor amount was saturated through a storage tank in which N, N-dimethylacetamide (solvent) was stored (see FIG. 3).

  Next, another core body having the same shape as the core body was placed under the core body and pushed up at 0.8 m / min to apply the PI precursor solution to the surface of the core body (see FIG. 6). At that time, the annular body was lifted up to about 30 mm. Thereby, a coating film of the PI precursor having a wet film thickness of about 500 μm was formed on the core. Thereafter, drying and heating were performed in the same manner as in Example 1 to obtain an endless belt.

  The obtained endless belt had the same result as in Example 1, and after stopping the inflow of nitrogen gas and interrupting the above-mentioned process for 24 hours, the endless belt was produced in the same manner again after the interruption. The endless belt obtained was of the same quality as that obtained initially.

(Example 3)
PAI resin synthesized from trimellitic anhydride and 4,4'-bis (3-aminophenoxy) biphenyl using N, N-dimethylacetamide as a solvent as a film-forming resin solution (solid content concentration 20% by mass, A viscosity of 10 Pa · s) was used.

  Other than that, an endless belt could be obtained in the same manner as in Example 1. However, since the PAI resin film was formed only by solvent drying, the heating conditions were 200 ° C. for 30 minutes and 250 ° C. for 30 minutes.

(Comparative Example 3)
In Example 3, an endless belt was produced in the same manner as in Example 1 except that the annular body was not covered and nitrogen gas was not introduced. The endless belt obtained first was of the same quality as the endless belt obtained first in Example 1.

  However, after interruption for 24 hours in the same manner as in Example 1, a similar attempt was made again, and a film was formed on the surface of the solution due to the drying of the solvent, which was inappropriate for application. .

(Comparative Example 4)
In Example 3, the annular body was covered, but when no inflow of nitrogen gas was performed, the endless belt obtained first was the same quality as the endless belt obtained first in Example 1. However, the belt produced after the interruption for 24 hours had no gloss on the surface and was in a cloudy state. This is presumably because this solution was affected by moisture in the air and caused the resin component to precipitate.

  From the above examples and comparative examples, in this example, even when a coating liquid (film forming resin) that is easily deteriorated by exposure to air is used, the coating liquid can be uniformly applied on the core body. It can be seen that it is.

It is a schematic block diagram which shows the time of a stop of the coating device which concerns on 1st Embodiment of this invention. It is a schematic block diagram which shows the time of application | coating of the coating device which concerns on 1st Embodiment of this invention. It is a schematic block diagram which shows an example of the solvent vapor | steam amount saturation means which inject | pours the inert gas with a solvent vapor | steam saturated state into a coating tank. It is a schematic block diagram which shows another example of the solvent vapor | steam amount saturation means which inject | pours the inert gas whose solvent vapor | steam amount is in a saturated state into a coating tank. It is a schematic block diagram which shows the time of a stop of the coating device which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which shows the time of application | coating of the coating device which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core body 2 Coating liquid 4 Coating film 5 Annular body 7 Coating tank 8 Annular sealing materials 10 and 11 Cover (lid member)
11A hole 15 arm 16 regulating member 17 fixing member 18 inert gas injection pipe 19 inert gas supply pipe 20 solvent 21 solvent storage tank

Claims (2)

A coating tank for storing the coating liquid and an annular body provided with a hole having an inner diameter larger than the outer diameter of the core body to which the coating liquid is applied are immersed in the coating liquid stored in the coating tank. A coating apparatus for applying a coating liquid to the surface of the core body by allowing the core body to be vertically raised from the coating liquid and passing through the holes with the axial direction of the core body vertical.
Covering the area from the outer periphery of the annular body to the upper edge of the coating tank, comprising a lid member,
And it further comprises an inert gas injection means for injecting an inert gas into the space surrounded by the lid member, the inner wall of the coating tank and the liquid surface of the coating liquid.
An applicator characterized by that.   Using the coating apparatus according to claim 1, after coating the coating liquid for film formation on the surface of the core body, the film is formed by performing any one of drying, heat curing, baking, or all treatment, A method for producing an endless belt, comprising removing the coating from a core.

Images