JP2006055777A - Coater and production method of endless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coater capable of coating evenly and uniformly a paint liquid on a core body and to provide a production method of an endless belt producing the endless belt having a uniform film thickness. <P>SOLUTION: The coater is equipped with a coating tank for storing a coating liquid and a ring body having a hole of a larger internal diameter than an external diameter of the core body to be coated with the coating liquid, wherein the core body, dipped in the coating liquid stored in the coating tank, is relatively raised from the coating liquid and made to pass through the hole while keeping the axial direction of the core body vertical so that the coating liquid is applied on the surface of the core body. Further, the coater is equipped with a cover which is arranged on an upper rim of the ring body and covers an area in the range of a peripheral part of the ring body to an upper rim of the coating tank. After the coating liquid for forming a film is coated on the surface of the core body by using this coater, any one of drying, heat setting and calcination or all treatments of them are carried out to form the film and this film is took out of the core body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a coating apparatus that can uniformly apply a coating liquid on a core, and a method of manufacturing an endless belt that includes a step of applying the coating liquid using the coating apparatus. The endless belt obtained by the production method is particularly preferably used for 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 may be abbreviated as PI and polyamideimide may be abbreviated as PAI.)

  In order to produce an endless belt with PI resin, the PI precursor solution is applied to the inner surface of the cylindrical body and dried while rotating (for example, refer to Patent Document 1), and the PI precursor solution is applied to the inner surface of the cylindrical body. There is known an inner surface coating method (see, for example, Patent Document 2) that develops, but in the method of forming a film on the inner surface of these cylindrical bodies, the core is removed from the cylindrical body when the PI precursor is heated. However, there is a disadvantage that it takes time.

  As another method for manufacturing an endless PI resin belt, a method is also proposed 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. (For example, see Patent Document 3). 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 in which the reaction is carried out by heating, and the number of man-hours for replacement is unnecessary. However, the precursor solution of the PI resin has a very high viscosity, and when it is intended to be applied onto the core body by the dip coating method, the film thickness may be too thick than desired.

On the other hand, a method of controlling the film thickness of the coating liquid using an annular body has been proposed (see, for example, Patent Document 4).
When coating is performed using an annular body, the thickness of the coating film is regulated by the gap between the core body and the circular hole of the annular body. However, since the thickness of the coating film after solvent drying varies depending on the solid content concentration, the solid content concentration of the coating liquid to be applied must be uniform. However, when the coating liquid has a high viscosity, it becomes difficult to stir the solution. Therefore, if the solvent evaporates, the solid content concentration of the coating liquid becomes non-uniform, resulting in non-uniform film thickness. In some cases, further improvements are desired.

  In addition, after application by the above-described application apparatus, for example, when the application is stopped at night, the coating liquid that has been raised on the upper surface of the annular body at the time of application remains on the upper surface of the annular body. In the gap portion between the core body and the circular hole, it may be partially solidified due to the evaporation of the solvent in the coating liquid or the influence of moisture in the air. This is because the solvent is hard to evaporate at room temperature and the solution is hardened by moisture in the air. In such a state, the solidified coating liquid exists inside the annular body as a foreign substance, and when applied, a thin portion of the film exists in a streak shape (hereinafter referred to as “axial streak”). As a result, the film thickness may become non-uniform, and further improvement is desired.

  On the other hand, it is necessary to raise the annular body to some extent at the time of application, but when the application is completed, the annular body may fall into the coating liquid, and bubbles may be entrained at that time. If air bubbles are mixed in the coating liquid, the air bubbles may adhere to the film when applied next time, resulting in non-uniform film thickness, and further improvement is desired.

In order to reduce the required amount of coating liquid, there is a method using an annular coating apparatus. FIG. 12 is a schematic cross-sectional view of a conventional annular coating device when stopped. In FIG. 12, 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, the core body 1 is inserted through the center of the annular sealing material 8, and the annular coating tank 7 is coated. Liquid 2 is contained. Thereby, the coating liquid 2 does not leak. When applying the coating liquid 2 to the core body 1, as shown in FIG. 13, another core body 1 ′ is connected to the bottom of the core body 1, and the core body 1 is pushed upward from the lower part of the annular coating tank 7, By passing through the hole 6 of the annular body 5, the coating film 4 is formed on the surface of the core body 1. The other core body 1 ′ may be an intermediate body that does not produce a belt.
In such an annular coating apparatus, the annular coating tank 7 can be made smaller than the conventional dip coating tank, and therefore there is an advantage that the required amount of the coating liquid 2 can be reduced.

In the above-described annular coating apparatus, it is sufficient that the solution flows in the annular coating tank 7 in a short time. However, since the coating liquid 2 actually accumulates at the corner portion of the bottom, non-uniformity occurs when the solution is added. There was a case. It is also desirable to further reduce the required amount of solution.
Furthermore, if the coating liquid 2 is continuously applied to the core body 1, the coating liquid 2 decreases and the coating liquid 2 needs to be further supplied. Foreign matter and bubbles may enter the gap with the circular hole, resulting in locally uneven film thickness, and further improvement is desired.

JP-A-57-74131 Japanese Patent Laid-Open No. 62-19437 Japanese Patent Laid-Open No. 61-273919 JP 2002-91027 A

  An object of this invention is to provide the coating device which can apply | coat a coating liquid uniformly on a core, and the manufacturing method of an endless belt which manufactures an endless belt with a uniform film thickness.

The object is achieved by the present invention described below.
That is, the present invention
<1> A coating tank for storing a coating liquid and an annular body provided with a hole having an inner diameter larger than the outer diameter of a core body to which the coating liquid is applied, and the coating liquid stored in the coating tank A coating apparatus for applying a coating liquid onto the surface of the core body by allowing the core body soaked to be perpendicular to the axial direction of the core body and relatively rising from the coating liquid and passing through the holes. The coating apparatus is further provided with a cover that is installed on the upper edge of the annular body and covers a region from the outer peripheral portion of the annular body to the upper edge of the coating tank.

<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, and the coating liquid stored in the coating tank A coating apparatus for applying a coating liquid onto the surface of the core body by allowing the core body soaked to be perpendicular to the axial direction of the core body and relatively rising from the coating liquid and passing through the holes. The inner peripheral side edge of the upper surface of the annular body is the uppermost part in the vertical direction.

<3> 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, and the coating liquid stored in the coating tank A coating apparatus for applying a coating liquid onto the surface of the core body by allowing the core body soaked to be perpendicular to the axial direction of the core body and relatively rising from the coating liquid and passing through the holes. The outer peripheral portion of the annular body is tapered downward in the vertical direction.

<4> An annular coating tank having an annular sealing material having a hole smaller than the outer diameter of the core body for storing the coating liquid and applying the coating liquid, and a hole having an inner diameter larger than the outer diameter of the core body The core body is passed through the hole of the annular seal material, the axial direction of the core body is vertical, and is relatively raised from the coating liquid and passes through the hole. An application device for applying a coating liquid onto the surface of the core body, wherein the bottom surface of the application tank has an inclined surface with the annular seal material side being down in the vertical direction. Device.

<5> An annular coating tank having an annular sealing material having a hole smaller than the outer diameter of the core body for storing the coating liquid and applying the coating liquid, and a hole having an inner diameter larger than the outer diameter of the core body The core body is passed through the hole of the annular seal material, the body axial direction is vertical, and the body liquid is relatively raised from the coating liquid to pass through the hole. By this, it is a coating device which apply | coats a coating liquid to the said core body surface, Comprising: It is a coating device further equipped with the shielding board in the bottom part of the said annular body.
<6> The coating apparatus according to <5>, further including a supply port that supplies the coating liquid to a side portion of the annular coating tank.

<7> Using the coating apparatus according to any one of <1> to <6>, after coating the coating liquid for film formation on the surface of the core, any one of drying, heat curing, and baking, or A process for producing an endless belt, wherein a film is formed by performing all treatments, and the film is removed from the core.
<8> The method for producing an endless belt according to <7>, wherein the coating liquid for forming a film is a polyimide precursor solution or a polyamideimide resin solution.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the endless belt which manufactures the coating device which can apply | coat a coating liquid uniformly on a core body, and the endless belt with a uniform film thickness can be provided.

<Coating device>
A coating apparatus according to a first aspect of the present invention includes a coating tank for storing a coating liquid, and an annular body provided with a hole having an inner diameter larger than the outer diameter of a core body for coating the coating liquid. The core body immersed in the coating liquid stored in the tank is set so that the axial direction of the core body is vertical and is relatively raised from the coating liquid so as to pass through the holes. A coating apparatus for coating, further comprising a cover that is installed on the upper edge of the annular body and covers a region from an outer peripheral portion of the annular body to the upper edge of the coating tank.
Hereinafter, the coating apparatus of 1st 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.

FIG. 1 is a schematic sectional view showing an example of the coating apparatus of the first present invention. However, the figure shows only the main part, and the core holding mechanism and other devices are omitted (the same applies to the following figures).
The coating apparatus shown in FIG. 1 includes a coating tank 3 for storing the coating liquid 2 and an annular body 5. The annular body 5 is provided with a hole 6 having an inner diameter larger than the outer diameter of the core body 1 to which the coating liquid 2 is applied. On the other hand, the upper edge of the annular body 5 further includes a cover 10 that covers a region from the outer peripheral portion of the annular body 5 to the upper edge of the coating tank 3.

  In the coating apparatus of the first aspect of the present invention, it is preferable that the annular body 5 and the cover 10 are fixed. By fixing the annular body 5 and the cover 10, the upper edge of the annular body 5 does not sink below the upper edge of the coating tank 3.

  Furthermore, in the coating apparatus of the first aspect of the present invention, the core body holding means for holding the core body, the first moving means for moving the holding means in the vertical direction, and / or the coating tank is moved in the vertical direction. You may have a 2nd moving means.

Application of the coating liquid 2 to the surface of the core body 1 using an example of the coating apparatus of the first aspect of the present invention is performed by putting the coating liquid 2 in the coating tank 3 and further in the coating liquid 2 as shown in FIG. The annular body 5 is immersed in Next, as shown in FIG. 2, the core body 1 is achieved by causing the core body 1 to be relatively raised from the coating liquid 2 through the hole 6 with the axial direction of the core body 1 being vertical. In this case, the speed at which the core body 1 is relatively raised from the coating liquid 2 is preferably 0.1 to 1.5 m / min.
In addition, "applying the coating liquid 2 to the surface of the core body 1" means apply | coating to the surface of the outer peripheral surface of the core body 1, and the surface of the layer, when there exists a layer in this surface. Further, “relatively raising the core body 1 from the coating liquid 2” is a relative relationship between the core body 1 and the liquid surface of the coating liquid 2, and “raising the core body 1 It stops "and the liquid level of the coating 2 is lowered".

  When the core body 1 is relatively lifted from the coating liquid 2 and passes through the hole 6, the annular body 5 is lifted together with the cover 10 by frictional resistance due to the viscosity of the solution. Since the annular body 5 is freely movable, the frictional resistance between the core body 1 and the annular body 5 is constant in the circumferential direction, that is, the gap between the surface of the core body 1 and the inner wall of the hole 6 is uniform. The annular body 5 moves, and the coating film 4 having a uniform film thickness is formed on the core body. Thus, since the film thickness is regulated by the annular body 5, a highly viscous solution can be used, and the dripping of the coating film due to gravity at the upper end of the core, which is a problem of the dip coating method, is reduced, and the circumferential direction However, the film thickness can be made uniform even in the axial direction.

  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 inner diameter of the circular hole 6, the inner diameter of the circular hole 6 is adjusted according to the desired film thickness. Further, the roundness of the inner diameter of the circular hole is important. When the roundness is low, the film thickness uniformity is lowered, and therefore the roundness is preferably 20 μm or less, and more preferably 10 μm or less. Of course, it is optimal that the roundness is 0 μm, but it is difficult in processing.

In the coating apparatus of the first aspect of the present invention, when the coating liquid 2 is not applied to the surface of the core body 1 described above, the cover 10 is provided so that the coating liquid 2 is evaporated from the coating tank 3. Can be prevented. As a result, when the coating liquid 2 is not applied to the surface of the core body 1, unevenness in the concentration of the surface of the coating liquid 2 in the coating tank 3 generated by the evaporation of the coating liquid 2 is prevented, and the core body It is possible to continuously apply the coating liquid 2 uniformly on one surface, and to obtain an endless belt having a uniform film thickness.
Furthermore, in the coating apparatus of the first aspect of the present invention, in order to prevent the coating liquid 2 from evaporating from the inside of the hole 6 of the annular body 5, the lid 11 is covered with the annular body 5 as shown in FIG. It may be covered.

  The core 1 is preferably a metal cylinder such as aluminum, stainless steel, nickel, or copper. Further, as will be described later, when an endless belt is to be manufactured, the axial length of the core body needs to be longer than the width of the target endless belt. In order to secure a margin width, it is preferable that the length of the endless belt is about 10 to 40% longer than the target width. The outer diameter of the core body 1 is preferably matched to the diameter of the target endless belt. On the other hand, the thickness should just be the thickness which can maintain the intensity | strength as a core.

  Furthermore, the core body 1 is demonstrated using FIG. FIG. 4 is a schematic cross-sectional view showing a cross-sectional view of an example of the core body 1. A holding plate 20 for holding the core body 1 is attached to both ends of the core body 1 shown in FIG. The holding plate may be fixed with screws or welded to the core body 1. The holding plate 20 may have a ventilation hole having an arbitrary shape such as a circular shape or a fan shape, a hole through which a mandrel passes, or a shaft 21 as necessary. Moreover, you may attach components for hanging or mounting.

  Further, the core body 1 may be provided with a releasability on the surface of the core body 1 in order to prevent the coating of the coating liquid 2 to be formed from adhering to the surface of the core body 1. For this purpose, there are a method in which the surface of the core body 1 is coated with a fluororesin or a silicone resin, or a release agent is applied to the surface of the core body 1.

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 polyimide precursor solution is used as the coating solution 2 and the film thickness exceeds 50 μm.
In order to prevent the above-described swelling, it is preferable to roughen the surface of the core body 1 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 produced from the coating film of the coating liquid 2 can exit to the outside through a slight gap formed between the core and the coating film of the coating liquid 2, and does not swell.

  As described later, when an endless belt is further produced as the coating liquid 2, a polyimide precursor (PI precursor) solution or a polyamideimide resin (PAI resin) solution is preferably used. As the PI precursor and PAI resin, various known ones can be used. Those solvents are aprotic polar solvents such as N-methylpyrrolidone, N, N-dimethylacetamide, and acetamide. In addition, although the density | concentration, viscosity, etc. of the solution of the said PI precursor or PAI resin are selected suitably, the solid content concentration of the solution preferably used for the coating apparatus of this invention is 10-40 mass%, and a viscosity is 1-100 Pa. -S.

  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 circular hole 6 may be stepped or curved as well as a linear inclined surface as shown in FIG. 1 as long as the lower part immersed in the solution is wide and the upper part is narrow. In order to process the roundness high, there may be a portion parallel to the core at the upper part of the inner wall surface of the circular hole.

As the coating apparatus of the first aspect of the present invention, the coating apparatus shown in FIG. 5 is also a preferred embodiment. FIG. 5 is a schematic sectional view showing another example of the coating apparatus of the first present invention.
In FIG. 5, the difference from FIG. 1 is that instead of the coating tank 3, an annular coating tank 7 provided with an annular sealing material 8 having a hole slightly smaller than the outer diameter of the core at the bottom is provided. . Application of the solution 2 to the surface of the core body 1 using the coating apparatus shown in FIG. 5 allows the core body 1 to be inserted through the center of the annular sealing material 8 and accommodates the solution 2 in the annular application tank 7. Thereby, the solution 2 does not leak. For coating, as shown in FIG. 6, another core body 1 ′ is connected under the core body 1 and pushed up from the lower part of the annular coating tank 7 to form a coating film 4 on the surface of the core body 1. To do. The other core body 1 ′ may be an intermediate body (a core body having a short length) that does not produce a belt. The function of the annular body 5 is the same as that of the example of the coating apparatus of the first aspect of the present invention.
In such a coating method (annular coating method), the annular coating tank 7 can be made smaller than the dip coating tank 3 of FIG.

A coating apparatus according to a second aspect of the present invention comprises: a coating tank for storing a coating liquid; and an annular body provided with a hole having an inner diameter larger than the outer diameter of a core body for coating the coating liquid. The core body immersed in the coating liquid stored in the tank is set so that the axial direction of the core body is vertical and is relatively raised from the coating liquid so as to pass through the holes. A coating apparatus for coating, wherein an inner peripheral side edge of the upper surface of the annular body is an uppermost portion in a vertical direction.
Hereinafter, the coating apparatus of 2nd this invention is demonstrated using FIG.

  FIG. 7 is a schematic cross-sectional view showing an annular body in an example of the second and third embodiments of the coating apparatus of the present invention to be described later. An example of the coating apparatus according to the second aspect of the present invention is that the cover 10 is not provided, and the annular body 5 has an annular shape shown in FIG. 7 in which the inner peripheral side edge of the upper surface is the top in the vertical direction. Except that it is changed to the body 25, it is the same as the other example of the coating apparatus of the first present invention shown in FIG.

  In the coating apparatus according to the second aspect of the present invention, the annular body 25 has the inner peripheral portion side edge on the upper surface in the vertical direction so that the solidified product of the coating liquid 2 does not adhere to the inner surface of the annular body 25. Therefore, even if the residue of the coating liquid 2 is on the upper surface of the annular body 25, it can be moved to the outer peripheral portion of the upper surface of the annular body 25. The coating liquid 2 that has moved to the outer peripheral portion can be removed by appropriately wiping it. Therefore, as described above, the solution does not solidify in the gap between the core body and the circular hole, and an endless belt having no streak running in the axial direction can be obtained. As a result, an endless belt having a uniform film thickness is obtained. be able to. The shape of the upper surface of the annular body 25 is not particularly limited as long as the inner peripheral side edge is the uppermost part in the vertical direction. However, as shown in FIG. Is preferred. In this case, it is more preferable that the inner peripheral side edge is 1 to 10 mm higher than the flat surface, and it is more preferable that the vicinity of the inner peripheral portion has an angle of 30 to 60 ° with respect to the flat surface.

Further, as another example of the coating apparatus according to the second aspect of the present invention, the cover 10 is not provided, and the annular body 5 has an inner peripheral side edge on the upper surface as shown in FIG. A coating apparatus similar to the example of the coating apparatus according to the first aspect of the present invention shown in FIG. 1 may be used except that the annular body 25 is the uppermost portion.
In addition, although the shape of the outer peripheral part of the annular body 25 in the coating apparatus of the second aspect of the present invention is not particularly limited, the outer peripheral part of the annular body 25 is tapered 30 downward in the vertical direction as shown in FIG. It is more preferable that

A coating apparatus according to a third aspect of the present invention includes a coating tank for storing a coating liquid, and an annular body provided with a hole having an inner diameter larger than the outer diameter of a core body for coating the coating liquid. The core body immersed in the coating liquid stored in the tank is set so that the axial direction of the core body is vertical and is relatively raised from the coating liquid so as to pass through the holes. In the coating apparatus for coating, the outer peripheral portion of the annular body has a tapered shape 30 downward in the vertical direction.
Hereinafter, the coating apparatus of 3rd this invention is demonstrated using FIG.

  An example of the coating apparatus according to the third aspect of the present invention is the annular body shown in FIG. 7 in which the cover 10 is not provided, and the annular body 5 has a tapered shape 30 whose outer peripheral portion is downward in the vertical direction. Except that it is changed to 25, it is the same as the other example of the coating apparatus of the first present invention shown in FIG. In addition, although the shape of the upper surface of the annular body 25 in an example of the coating apparatus of the third aspect of the present invention is not particularly limited, as shown in FIG. 7, the annular body 25 has an inner peripheral side edge on the upper surface in the vertical direction. It is more preferable that it is at the top.

  Even if the annular body 25 descends into the coating tank 3 after the application of the coating liquid 2 to the core body 1 is completed, the annular body 25 has a tapered shape 30 with the outer peripheral portion being vertically downward. It is possible to prevent air bubbles from being entrained in the coating liquid 2. Thereby, when the coating liquid 2 is apply | coated to the core 1, it can prevent that a bubble adheres to a membrane | film | coat. The tapered portion is preferably 30 to 60 ° with respect to the bottom surface and 5 to 15 mm in length.

  Further, as another example of the coating apparatus according to the third aspect of the present invention, the cover 10 is not provided, and the annular body 5 has a peripheral portion as shown in FIG. A coating apparatus similar to the example of the coating apparatus according to the first aspect of the present invention shown in FIG. 1 may be mentioned except that the annular body 25 is changed to 30.

A coating apparatus according to a fourth aspect of the present invention includes an annular coating tank that stores a coating liquid and has an annular sealing material having a hole smaller than an outer diameter of a core body to which the coating liquid is applied, and an outer surface of the core body. An annular body provided with a hole having an inner diameter larger than the diameter, and a core body through which the core body is passed through the hole of the annular sealing material, the axial direction of the core body being vertical, from the coating liquid A coating device that applies a coating liquid to the surface of the core body by allowing the coating body to pass through the holes while being relatively lifted, wherein the bottom surface of the coating tank has an inclined surface in which the annular seal material direction is downward in the vertical direction It is characterized by having.
Hereinafter, the coating apparatus of the 4th this invention is demonstrated using drawing.

FIG. 8 is a schematic cross-sectional view showing an example of a coating apparatus according to the fourth aspect of the present invention. In the example of the coating apparatus of the fourth aspect of the present invention shown in FIG. 8, the cover 10 is not provided, and the bottom surface of the annular coating layer 7 is formed with an inclined surface 9 in which the direction of the annular sealing material 8 is downward in the vertical direction. Except for this, it is the same as other examples of the coating apparatus of the first present invention shown in FIG. The inclined surface 9 makes it easy for the solution 2 to flow in the direction of the annular sealing material 8, so that it does not accumulate at the bottom, and is uniform even when the amount of the coating liquid 2 is reduced. can get. The angle of the inclined surface 9 is preferably 5 to 30 ° with respect to the horizontal. If the angle of the inclined surface 9 is less than 5 °, the flow of the coating liquid 2 may stagnate, and if it exceeds 30 °, the amount of the coating liquid 2 that can be stored may be reduced.
Further, the inclined surface may be a curved surface. In the case of a curved surface, the inside of the annular coating tank is scraped off with a curved spatula, thereby facilitating cleaning of the solution after coating.
Further, the inclined surface may be provided on a part of the bottom surface of the annular coating layer 7, but it is preferable that the entire portion of the bottom surface of the annular coating layer 7 excluding the annular sealing material 8 is an inclined surface.
In the coating device of the fourth aspect of the present invention, an arm 15 for supporting the annular body 5 may be provided on the annular body 5 as shown in FIG. Furthermore, although the cover 10 is not provided in FIG. 8, it is also a preferable aspect that the cover 10 is provided on the upper edge of the annular body 5.

A coating apparatus according to a fifth aspect of the present invention includes an annular coating tank that stores a coating liquid and has an annular sealing material having a hole smaller than the outer diameter of the core body to which the coating liquid is applied, and an outer surface of the core body. An annular body provided with a hole having an inner diameter larger than the diameter, and a core body through which the core body is passed through the hole of the annular sealing material, the axial direction of the core body being vertical, from the coating liquid A coating apparatus for applying a coating liquid to the surface of the core body by allowing the core body surface to pass through the holes while being relatively lifted, further comprising a shielding plate at the bottom of the annular body. The coating device of the fifth aspect of the present invention preferably further includes a supply port for supplying the coating liquid to the side portion of the annular coating tank.
Hereinafter, the coating apparatus of the 5th this invention is demonstrated using drawing.

FIG. 9 is a schematic sectional view showing an example of the coating apparatus of the fifth aspect of the present invention. An example of the coating apparatus of the fifth invention shown in FIG. 9 is the first invention shown in FIG. 5 except that the cover 10 is not provided and the shielding plate 12 is provided at the bottom of the annular body 5. This is the same as other examples of the coating apparatus.
Moreover, in the coating device of the fifth aspect of the present invention, as shown in FIG. 9, an arm 15 for supporting the annular body 5 may be provided on the annular body 5. Furthermore, although the cover 10 is not provided in FIG. 9, it is also a preferable aspect that the cover 10 is provided on the upper edge of the annular body 5.

  If the coating liquid 2 is continuously applied to the surface of the core body 1 using the coating apparatus, the coating liquid 2 is decreased and finally the coating becomes impossible. Therefore, it is necessary to replenish the coating liquid 2 before that happens. As a method for replenishing the coating liquid 2, a method of charging the coating liquid 2 from the upper part of the annular coating tank 7 can be mentioned. However, in the method of supplying the coating liquid 2 from the upper part of the annular coating tank 7, bubbles are mixed. Also, when the coating liquid 2 is first introduced into the annular coating tank 7, bubbles are mixed. In an example of the coating apparatus of the fifth aspect of the present invention, the shielding plate 12 is provided at the bottom of the annular body 5, so that the coating liquid 2 outside the annular body 5 is applied in the direction toward the inside of the annular body. When moving, it is possible to prevent foreign matters and bubbles mainly existing on the surface side (shallow place) of the coating solution 2 solution from flowing in easily with the movement of the solution. As a result, it is possible to prevent the formation of streaks due to foreign matters or bubbles in the coating film formed by applying the coating liquid 2, and the film thickness can be made uniform.

  The supply liquid of the coating liquid 2 may be added every time the coating liquid 2 is applied to the surface of the core body 1 or may be added together after the coating liquid 2 is applied to the surface of the core body 1 several times. May be. Moreover, you may add gradually in the middle of apply | coating the coating liquid 2 to the core 1 surface.

Next, another example of the coating apparatus of the fifth aspect of the present invention will be described with reference to the drawings.
FIG. 10 is a schematic sectional view showing another example of the coating apparatus of the fifth aspect of the present invention. Other examples of the coating apparatus of the fifth aspect of the present invention shown in FIG. 10 are the fifth shown in FIG. 9 except that the supply port 13 for supplying the coating liquid 2 is provided on the side surface of the circulation coating layer 7. It is the same as that of an example of the coating device of this invention.
In the coating apparatus according to the fifth aspect of the present invention, the method of supplying the coating liquid 2 includes a method of feeding the coating liquid 2 from the upper part of the annular coating tank 7 described above. It is preferable to supply the coating liquid 2 from the supply port 13. In this case, when the coating liquid 2 has a high viscosity of 1 to 100 Pa · s, a boundary is formed between the coating liquid 2 existing in the annular coating tank 7 and the newly flowing coating liquid 2. It may appear as a streak in the coating film. In order to prevent this, it is necessary to prevent the inflowing coating liquid 2 from directly touching the core body. Therefore, in the coating apparatus of the fifth aspect of the present invention, the newly flowing coating liquid 2 is once struck against the shielding plate 12. Thereby, there is no boundary between the coating liquids 2, and as a result, the film thickness can be made uniform.

  Moreover, it is preferable that there are a plurality of supply ports 13 symmetrically. It is preferable that the height of the supply port 13 is a height at which the outlet of the supply port 13 is applied to the shielding plate 11 from the outer side surface of the ring-shaped body 5 on standby. In this way, when the coating liquid 2 is supplied from the supply port 13, the supplied coating liquid 2 hits the outer surface of the annular body 5 and / or the shielding plate 12, the direction thereof is changed, and the annular coating tank 7. Get inside. Therefore, the supplied coating liquid 2 does not directly hit the core body 1, and it becomes difficult for the coating film to form streaks.

  FIG. 11 shows an example of the annular body 5 and the shielding plate 11 in a three-dimensional manner. FIG. 11 is a schematic perspective view showing an example of the annular body 5 and the shielding plate 12. The shielding plate 12 may be integrated with the annular body 5 or attached later. The thickness of the shielding plate 12 is preferably 30% or less of the average thickness of the annular body 5, and more preferably 5% or less. The material of the shielding plate 12 is preferably selected from metals, plastics and the like that are not attacked by the solvent of the coating liquid 2, and may be a soft material in the form of a film. The height of the shielding plate 12 is sufficient if a sufficient length can be ensured from the lower portion of the shielding plate 12 to the bottom of the annular coating tank 7 at the time of application. % Or less. If it is a shielding board of such a shape, the influence on coating-film formation is very small.

<Method for producing endless belt>
The production method of the endless belt of the present invention is any one of drying, heat-curing, and firing after applying the coating liquid for film formation to the surface of the core 1 using the above-described coating apparatus of the present invention. All the treatments are performed to form a film, and the film is removed from the core.
Further, as the coating liquid for forming a film, a PI precursor solution and a PAI resin solution are preferable in terms of strength, dimensional stability, heat resistance and the like of the film to be obtained. Hereinafter, the case where the PI precursor solution or the PAI resin solution is used as the coating liquid for film formation will be described for the production method of the endless belt of the present invention.

In the method for producing an endless belt of the present invention, the coating film formed by applying 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 removed. Dry to the extent that does not deform. 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). When the film-forming solution is a PI precursor solution, the PI precursor film is then heated at 250 to 450 ° C., preferably around 300 to 350 ° C. for 20 to 60 minutes to cause a condensation reaction. A resin 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 obtained endless belt is used as a transfer belt or a contact charging belt, a conductive substance is dispersed in the film forming solution as necessary. 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
Carbon black (trade name: Special Black 4, Degussa Huls) mixed with PI precursor solution (trade name: U varnish A, manufactured by Ube Industries, 18% concentration) at a solid content mass ratio of 23%, then facing collision Dispersed with a mold disperser. Furthermore, a silicone leveling agent (trade name: DC3PA, manufactured by Dow Corning Toray Silicone) was added so as to have a concentration of 500 ppm to obtain a coating solution 2.

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. The circularity of the cylinder was 20 μm or less. In addition, a holding plate having a thickness of 15 mm, an outer diameter that fits into the cylinder, four 100 mm diameter vent holes 12 and a 20 mm diameter hole in the center is made of the same aluminum material, and is fitted into the cylinder. The core body 1 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 body 1. 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 wrapping around the side surface of the core.

Next, the coating liquid 2 was used to form a coating film 4 of the PI precursor on the surface (outer peripheral surface) of the core body 1 using an annular coating apparatus shown in FIG. At this time, as the annular body 5, an aluminum body having an outer diameter of 420 mm, an inner diameter of 367.1 mm at the minimum part of the circular hole 6 and a height of 50 mm was used. The inner wall of the annular body 5 is linearly inclined, and the inclination angle with respect to the vertical line is 7 °. A 2 mm portion parallel to the core 1 was formed on the upper end, and the roundness of the inner diameter was 8 μm.
In addition, 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 460 mm, and was attached and fixed to the upper surface of the annular body 5 to form a cover 10.

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 surface of the annular coating tank 7 having an inner diameter of 450 mm and a height of 100 mm, and the core body 1 is passed through the center. did. The coating liquid 2 was put into the annular coating tank 7, and the annular body 5 provided with the cover 10 was arranged to prevent solvent evaporation during the standby time.
Next, as shown in FIG. 6, a core body 1 ′ having the same shape as that of the core body 1 is disposed under the core body 1 and pushed up at 0.8 m / min, so that the PI precursor solution is formed on the surface of the core body 1. Application was performed. At that time, the annular body 5 was lifted by about 20 mm. Thereby, a coating film 4 of a PI precursor having a wet film thickness of about 500 μm was formed on the core body 1.

A stainless steel shaft with a diameter of 20 mm is passed through the center hole of the holding plate of the core body 1 on which the coating film 4 of the PI precursor has been formed, placed on a rotating table, leveled, and rotated at 6 rpm, for 20 minutes at 80 ° C. The coating film 4 of PI precursor was dried by heating at 130 ° C. for 30 minutes. 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 1 on which the PI precursor film is formed is made vertical, the shaft is removed and placed on a table, put into a heating device, and heated and reacted at 200 ° C. for 30 minutes and 340 ° C. for 30 minutes. A PI resin film was formed on the surface.

After cooling the core body 1 on which the PI resin film was formed at room temperature, the PI resin film was extracted from the core body 1 while blowing air between the core body 1 and the PI resin film to obtain an endless belt. The film thickness of the endless belt was 75 μm and uniform. The endless belt was cut from each end by about 35 mm to obtain an endless belt having a length of 360 mm.
The obtained endless belt had a semiconductivity of about 10 ¹⁰ Ωcm when measured for volume resistivity at 100 V, and could be used as an electrophotographic transfer belt.
Furthermore, after the above process was interrupted for 4 hours, an endless belt was obtained in the same manner. The endless belt obtained after interruption for 4 hours was similar to the endless belt obtained first.

(Comparative Example 1)
In Example 1, an endless belt was obtained in the same manner as in Example 1 except that the cover 10 was not provided on the annular body 5. The obtained endless belt was the same as the endless belt obtained first in Example 1 (before interruption for 4 hours).
However, after suspending for 4 hours in the same manner as in Example 1, the endless belt obtained in the same manner again had a non-uniform film thickness of 80 to 84 μm.
From the above, when there is the cover 10 as in Example 1, there was no such problem even if it was interrupted for 4 hours. In Comparative Example 1, the PI resin was applied from the coating tank 3 during 4 hours. It is considered that the film thickness became non-uniform due to evaporation of the precursor solution.

(Example 2)
Without installing the lid 10, the coating liquid 2 prepared in Example 1 was carried out using the annular coating apparatus having the configuration shown in FIG. 5 except that the annular body 25 shown in FIG. 7 was used instead of the annular body 5. It was applied to the surface (outer peripheral surface) of the core body 1 produced in Example 1, and a PI precursor coating film 4 was formed on the surface of the core body 1. The annular body 25 is made of aluminum having an outer diameter of 420 mm, a minimum inner diameter of 367.1 mm of the circular hole 6 and a height of 50 mm, the inner wall is linearly inclined, and the inclination angle with respect to the vertical line is 10 °. did. The upper surface of the annular body 25 is 45 ° with respect to the flat surface so that the inner peripheral side edge is the uppermost part in the vertical direction (the height from the flat surface of the upper surface of the annular body 25 is 3 mm). The slope (convex part) is provided, and the outer peripheral part is not tapered, but is a vertical wall. Furthermore, 2 mm of a portion parallel to the core body 1 was formed at the upper end of the inner wall of the hole 6 of the annular body 25, and the roundness of the inner diameter of the portion parallel to the core body 1 was 8 μm.

  On the other hand, a hole with an inner diameter of 386 mm was made in the bottom surface of the annular coating tank 7 having an inner diameter of 450 mm and a height of 100 mm. An annular sealing material 8 made of a hard polyethylene resin having a thickness of 0.5 mm and having a hole with an inner diameter of 364.5 mm was attached to the back surface of the bottom surface, and the core body 1 was passed through the center. 3 kg of the coating liquid 2 was put into the annular coating tank 7 and the annular body 25 was arranged. Next, in the same manner as in Example 1, the core body 1 ′ was placed under the core body 1 and applied by pushing up at 0.8 m / min. At that time, the annular body 25 was lifted by about 50 mm. Thereby, a coating film 4 of a PI precursor having a wet film thickness of about 500 μm was formed on the core body 1.

A stainless steel shaft with a diameter of 20 mm is passed through the center hole of the holding plate of the core body 1 on which the coating film 4 of the PI precursor has been formed, placed on a rotating table, leveled, and rotated at 6 rpm, for 20 minutes at 80 ° C. The coating film 4 of PI precursor was dried by heating at 130 ° C. for 30 minutes. As a result, 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 1 on which the PI precursor film is formed is made vertical, the shaft is removed, and it is placed on a table, put in a heating device, heated and reacted at 200 ° C. for 30 minutes and 340 ° C. for 30 minutes, and the surface of the core body 1 A PI resin film was formed.

After cooling the core body 1 with the PI resin film formed at room temperature, the air is blown between the core body 1 and the PI resin film, and the PI resin film is extracted from the core body 1 and cut at about 35 mm from both ends. Thus, an endless belt having a length of 360 mm was obtained. Subsequently, three endless belts were produced in the same manner. Further, after the fourth endless belt was manufactured, the coating apparatus was stopped overnight, and then four endless belts were similarly manufactured. All eight endless belts had a uniform film thickness of 80 μm, and there were no axial streaks.
The obtained endless belt had a semiconductivity of about 10 ¹⁰ Ωcm when measured for volume resistivity at 100 V, and could be used as an electrophotographic transfer belt.

(Comparative Example 2)
In Example 2, the upper surface has the same configuration as that of the annular body 25 except that a 45 ° slope is not provided with respect to the flat surface that is provided so that the inner peripheral side edge is the uppermost portion in the vertical direction. First, four endless belts were obtained in the same manner as in Example 2 except that the annular body was used instead of the annular body 25. The four endless belts had no problem. Furthermore, in the four endless belts produced after stopping overnight, streaks were generated in the axial direction of all the four endless belts, and the film thickness of the endless belt was 70 to 80 μm and was not uniform.
This is because the liquid puddle is formed on the inner peripheral side of the upper surface of the annular body after the coating apparatus is stopped overnight, and partially solidifies, thereby forming a streak in the axial direction of the film, resulting in uneven film thickness. It was confirmed that

  On the other hand, even if the coating liquid 2 hangs down from the core body 1 in the annular body 25 provided with the inclined surface provided so that the inner peripheral side edge is the uppermost part in the vertical direction as in the second embodiment. Since it moves in the outer circumferential direction of the annular body 25, no liquid pool is formed between the annular body 25 and the core body 1, and an endless belt having a uniform film thickness is obtained without any axial streaking.

(Example 3)
Without installing the lid 10, the coating liquid 2 prepared in Example 1 was carried out using the annular coating apparatus having the configuration shown in FIG. 5 except that the annular body 25 shown in FIG. 7 was used instead of the annular body 5. It was applied to the surface (outer peripheral surface) of the core body 1 produced in Example 1, and a PI precursor coating film 4 was formed on the surface of the core body 1. The annular body 25 is made of aluminum having an outer diameter of 420 mm, a minimum inner diameter of the circular hole of 67.1 mm, and a height of 50 mm, and an outer diameter of 420 mm and a minimum diameter of the circular hole of 67.1 mm of the inner diameter of 367.1 mm. A 50 mm aluminum product was prepared. The inner wall was linearly inclined, and the inclination angle with respect to the vertical line was 10 °. Further, the annular body 25 is not provided with the inclined surface in the second embodiment, and the outer peripheral portion side has a tapered shape of C10 mm. Furthermore, 2 mm of a portion parallel to the core body 1 was formed at the upper end of the inner wall of the hole 6 of the annular body 25, and the roundness of the inner diameter of the portion parallel to the core body 1 was 8 μm.

  On the other hand, a hole with an inner diameter of 386 mm was made in the bottom surface of the annular coating tank 7 having an inner diameter of 450 mm and a height of 100 mm. An annular sealing material 8 made of a hard polyethylene resin having a thickness of 0.5 mm and having a hole with an inner diameter of 364.5 mm was attached to the back surface of the bottom surface, and the core body 1 was passed through the center. 3 kg of the coating liquid 2 was put into the annular coating tank 7 and the annular body 25 was arranged. Next, in the same manner as in Example 1, the core body 1 ′ was placed under the core body 1 and applied by pushing up at 0.8 m / min. At that time, the annular body 25 was lifted by about 50 mm. Thereby, a coating film 4 of a PI precursor having a wet film thickness of about 500 μm was formed on the core body 1.

A stainless steel shaft with a diameter of 20 mm is passed through the center hole of the holding plate of the core body 1 on which the coating film 4 of the PI precursor has been formed, placed on a rotating table, leveled, and rotated at 6 rpm, for 20 minutes at 80 ° C. The coating film 4 of PI precursor was dried by heating at 130 ° C. for 30 minutes. As a result, 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 1 on which the PI precursor film is formed is made vertical, the shaft is removed, and it is placed on a table, put in a heating device, heated and reacted at 200 ° C. for 30 minutes, and 340 ° C. for 30 minutes. A PI resin film was formed.

After cooling the core body 1 with the PI resin film formed at room temperature, the air is blown between the core body 1 and the PI resin film, and the PI resin film is extracted from the core body 1 and cut at about 35 mm from both ends. Thus, an endless belt having a length of 360 mm was obtained. Subsequently, three endless belts were produced in the same manner. Further, after the fourth endless belt was manufactured, the coating apparatus was stopped overnight, and then four endless belts were similarly manufactured. The film thickness of the eight endless belts in total was 80 μm and uniform (the difference between the maximum film thickness and the minimum film thickness was less than 3 μm), and no film had any bubbles.
The obtained endless belt had a semiconductivity of about 10 ¹⁰ Ωcm when measured for volume resistivity at 100 V, and could be used as an electrophotographic transfer belt.

(Comparative Example 3)
In Example 3, four endless belts were obtained in the same manner as in Example 3 except that the entire outer peripheral portion side of the annular body 25 was set in the vertical direction. The four endless belts had no problem with the first endless belt produced first, but the second and subsequent belts had a problem of air bubbles mixing into the film, and the endless belt had a film thickness of 70 to 80 μm. It was uniform.
When the coating apparatus stopped, the annular body 25 dropped into the solution, and bubbles were mixed in the coating liquid 2 in the coating tank 3. Since the bubbles adhered to the second and subsequent films, the endless belt was formed with bubbles. On the other hand, when the tapered portion was provided on the outer peripheral surface side of the annular body 25 as in Example 1, no bubbles were mixed even when the annular body 25 dropped into the solution.

Example 4
The coating liquid 4 prepared in Example 1 is applied to the surface (outer peripheral surface) of the core body 1 produced in Example 1 by the annular coating apparatus shown in FIG. Formed on one surface.
Specifically, a hole with an inner diameter of 386 mm was made in the bottom surface of the annular coating tank 7 having an inner diameter of 450 mm and a height of 100 mm. An inclined surface 9 having an angle of 10 ° was formed on the bottom surface. Furthermore, an annular sealing material 8 made of hard polyethylene resin having a thickness of 0.5 mm and having a hole with an inner diameter of 364.5 mm was attached to the back surface of the bottom surface of the annular coating tank 7, and the core body 1 was passed through the center. 3 kg of the coating liquid 2 was placed in the annular coating tank 7 and the annular body 5 was arranged. Next, in the same manner as in Example 1, the core body 1 ′ was placed under the core body 1, and the coating was performed by pushing up at 0.8 m / min. At that time, the annular body 25 was lifted by about 20 mm. Thereby, the coating film 4 of the PI precursor with a wet film thickness of about 500 μm was formed on the surface (outer peripheral surface) of the core body 1. The annular body 5 was made of aluminum having an outer diameter of 420 mm, an inner diameter of 367.1 mm at the minimum part of the circular hole 6 and a height of 50 mm.

A stainless steel shaft with a diameter of 20 mm is passed through the center hole of the holding plate of the core body 1 on which the coating film 4 of the PI precursor has been formed, placed on a rotating table, leveled, and rotated at 6 rpm, for 20 minutes at 80 ° C. The coating film 4 of PI precursor was dried by heating at 130 ° C. for 30 minutes. As a result, 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 1 on which the PI precursor film is formed is made vertical, the shaft is removed, and it is placed on a table, put in a heating device, heated and reacted at 200 ° C. for 30 minutes, and 340 ° C. for 30 minutes. A PI resin film was formed.

After cooling the core body 1 with the PI resin film formed at room temperature, the air is blown between the core body 1 and the PI resin film, and the PI resin film is extracted from the core body 1 and cut at about 35 mm from both ends. Thus, an endless belt having a length of 360 mm was obtained. The film thickness of the obtained endless belt was all 80 μm and uniform (the difference between the maximum film thickness and the minimum film thickness was less than 3 μm).
The obtained endless belt had a semiconductivity of about 10 ¹⁰ Ωcm when measured for volume resistivity at 100 V, and could be used as an electrophotographic transfer belt.

(Comparative Example 4)
In Example 4, an endless belt was obtained in the same manner as in Example 4 except that the inclined surface 9 was not formed on the bottom surface of the annular coating tank 7. The obtained endless belt was non-uniform with a film thickness of 74 to 82 μm.
This is because, when the adhesion of the coating liquid 2 to the core body 1 is stable, it acts so that the shear stress is uniform between the annular body 5 and the core body 1, so that the annular body 5 and the core are covered all around. The distance between the bodies is kept constant, and as a result, a film having a uniform film thickness can be obtained. However, when the coating liquid adheres unstablely to the core as in Comparative Example 4, it is partially Since the coating liquid is deficient, it is considered that a minute movement is induced in the annular body 5, and as a result, the film has a non-uniform film thickness.

(Example 5)
The coating liquid 4 prepared in Example 1 is applied to the surface (outer peripheral surface) of the core body 1 produced in Example 1 by using the annular coating apparatus shown in FIG. Formed on one surface.
Specifically, as the annular body 5, an aluminum body having an outer diameter of 420 mm, an inner diameter of 367.1 mm at the minimum part of the circular hole 6 and a height of 50 mm was used. Moreover, the shielding board 9 was produced by winding the sheet | seat which consists of PET films on the outer side of the cyclic | annular body 5 cyclically | annularly. The height of the shielding plate 9 from the bottom of the annular body 5 is 30 mm. Furthermore, a hole with an inner diameter of 386 mm was made in the bottom surface of the annular coating tank 7 having an inner diameter of 450 mm and a height of 100 mm. An annular sealing material 8 made of hard polyethylene resin having a thickness of 0.5 mm and having a hole with an inner diameter of 364.5 mm was attached to the back surface of the bottom surface of the annular coating tank 7, and the core body 1 was passed through the center. 3 kg of the coating liquid 2 was placed in the annular coating tank 7 and the annular body 5 was arranged. Next, in the same manner as in Example 1, the core body 1 ′ was placed under the core body 1, and the coating was performed by pushing up at 0.8 m / min. At that time, the annular body 25 was lifted by about 20 mm. Thereby, the coating film 4 of the PI precursor with a wet film thickness of about 500 μm was formed on the surface (outer peripheral surface) of the core body 1.

A stainless steel shaft with a diameter of 20 mm is passed through the center hole of the holding plate of the core body 1 on which the coating film 4 of the PI precursor has been formed, placed on a rotating table, leveled, and rotated at 6 rpm, for 20 minutes at 80 ° C. The coating film 4 of PI precursor was dried by heating at 130 ° C. for 30 minutes. As a result, 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 1 on which the PI precursor film is formed is made vertical, the shaft is removed, and it is placed on a table, put in a heating device, heated and reacted at 200 ° C. for 30 minutes, and 340 ° C. for 30 minutes. A PI resin film was formed.

After cooling the core body 1 with the PI resin film formed at room temperature, the air is blown between the core body 1 and the PI resin film, and the PI resin film is extracted from the core body 1 and cut at about 35 mm from both ends. Thus, an endless belt having a length of 360 mm was obtained. The film thickness of the obtained endless belt was all 80 μm and uniform (the difference between the maximum film thickness and the minimum film thickness was less than 3 μm).
The obtained endless belt had a semiconductivity of about 10 ¹⁰ Ωcm when measured for volume resistivity at 100 V, and could be used as an electrophotographic transfer belt.

(Comparative Example 5)
In Example 5, an endless belt was obtained in the same manner as in Example 5 except that the shielding plate 9 was not wound around the annular body 5. The obtained endless belt was non-uniform with a film thickness of 74 to 82 μm.
This is because, when the adhesion of the coating liquid 2 to the core body 1 is stable, it acts so that the shear stress is uniform between the annular body 5 and the core body 1, so that the annular body 5 and the core are covered all around. The distance between the bodies is kept constant, and as a result, a film having a uniform film thickness can be obtained. However, when the coating liquid adheres unstablely to the core as in Comparative Example 4, it is partially Since the coating liquid is deficient, it is considered that a minute movement is induced in the annular body 5, and as a result, the film has a non-uniform film thickness.

(Example 6)
In Example 5, when the application is performed once, the coating liquid 3 is reduced by about 300 ml. Therefore, when three core bodies 1 are applied, the liquid level of the coating liquid 3 is lowered, and the next application is hindered. Therefore, in the coating apparatus of Example 5, four supply ports 13 having an inner diameter of 8 mm were provided on the side surface of the annular coating tank 7 as shown in FIG. The mounting position was 60 mm from the upper end of the annular coating tank 7 and the height at which the inflowing liquid hits the shielding plate 9. A fluororesin tube having an inner diameter of 8 mm was connected to the supply port 13. Each time coating was completed, about 300 ml of coating liquid 2 was supplied at a pressure of 0.5 Pa. An endless belt was continuously obtained in the same manner as in Example 5 except that about 300 ml of the coating liquid 2 was supplied from the supply port 12. As a result, a coating film 4 of always good PI precursor could be obtained, and a uniform endless belt having a film thickness of 80 μm was continuously obtained.

(Comparative Example 6)
In Example 6, an endless belt was continuously obtained while supplying about 300 ml of the coating liquid 2 from the supply port 12 in the same manner as in Example 6 except that the shielding plate 9 was removed. As a result, thinning of the axial streaks was gradually observed, and the film thickness was not reduced.

It is a schematic sectional drawing at the time of a stop of an example of the coating device of the 1st present invention. It is a schematic sectional drawing at the time of application | coating of an example of the coating device of 1st this invention. It is a schematic sectional drawing at the time of a stop of an example of the coating device of the 1st this invention which covered the lid | cover. 2 is a schematic cross-sectional view showing a cross-sectional view of an example of a core body 1. FIG. It is a schematic sectional drawing at the time of the stop of the other example of the coating device of 1st this invention. It is a schematic sectional drawing at the time of application | coating of the other example of the coating device of 1st this invention. It is a schematic sectional drawing which shows an example of the annular body of the coating device of 2nd and 3rd this invention. It is a schematic sectional drawing which shows an example of the coating device of 4th this invention. It is a schematic sectional drawing which shows an example of the coating device of 5th this invention. It is a schematic sectional drawing which shows the other example of the coating device of 5th this invention. It is a schematic perspective view which shows an example of the annular body 5 and the shielding board 12. FIG. It is a schematic sectional drawing at the time of the stop of the conventional annular coating device. It is a schematic sectional drawing at the time of application | coating of the conventional annular coating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core body 2 Coating liquid 3 Coating tank 4 Coating film 5 Annular body 6 Hole 7 Annular application tank 8 Annular sealing material 9 Slope 10 Cover 11 Lid 12 Shield plate 13 Supply port 15 Arm 20 Holding plate 21 Axis 25 Annular body

Claims (8)

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 causing 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.
A coating apparatus, further comprising a cover that is installed on the upper edge of the annular body and covers a region from an outer peripheral portion of the annular body to the upper edge of the coating tank. 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 causing 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.
The coating apparatus according to claim 1, wherein an inner peripheral side edge of the upper surface of the annular body is an uppermost part in a vertical direction. 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 causing 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.
The outer peripheral part of the said cyclic | annular body is a taper shape toward the bottom in the perpendicular direction, The coating device characterized by the above-mentioned. An annular coating tank having an annular sealing material having a hole smaller than the outer diameter of the core body for storing the coating liquid and applying the coating liquid, and a hole having an inner diameter larger than the outer diameter of the core body are provided. The core body is passed through the hole of the annular sealing material, the axis direction of the core body is vertical, and the core body is relatively raised from the coating liquid to pass through the hole. An application device for applying a coating liquid to the surface of the core body,
The coating apparatus characterized in that the bottom surface of the coating tank has an inclined surface with the annular sealing material side facing down in the vertical direction. An annular coating tank having an annular sealing material having a hole smaller than the outer diameter of the core body for storing the coating liquid and applying the coating liquid, and a hole having an inner diameter larger than the outer diameter of the core body are provided. The core body is passed through the hole of the annular sealing material, the axis direction of the core body is vertical, and the core body is relatively raised from the coating liquid to pass through the hole. An application device for applying a coating liquid to the surface of the core body,
Furthermore, the coating apparatus is equipped with the shielding board in the bottom part of the said annular body.   The coating apparatus according to claim 5, further comprising a supply port that supplies the coating liquid to a side portion of the annular coating tank.   Using the coating apparatus according to any one of claims 1 to 6, after coating the coating liquid for film formation on the surface of the core, any one of drying, heat curing, baking, or all treatments is performed. And forming a film, and removing the film from the core body.   The method for producing an endless belt according to claim 7, wherein the coating liquid for forming a film is a polyimide precursor solution or a polyamideimide resin solution.

Images