JP2007144292A - Coating formation method and manufacturing method of seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating formation method which prevents the generation of syneresis line effectively upon smoothing with a blade, and to provide a manufacturing method of a seamless belt by the coating formation method. <P>SOLUTION: The coating formation method which is employed for applying the coating liquid on a rotor and for smoothing with the blade which satisfies either one of the followings (1)-(3): (1) the application is conducted with a nozzle which is capable of coating the whole face of the coated width at once and the smoothing is conducted by sliding a blade narrower than the coated width, (2) the smoothing is conducted by separating the blade to the front side using a blade of which the leading edge is inclined and (3) a blade with a width broader than the coated width is used, and the blade is rotated on one point of the blade, then the blade is separated to the front side to conduct the smoothing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coating film forming method capable of forming a coating film without causing a seam in a rotating body, and a method for producing an endless belt by applying a film forming resin solution on a core body by the method. The endless belt is particularly preferably used for an electrophotographic image forming apparatus 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. 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. The material is preferably a polyimide resin or a polyamideimide resin in terms of strength, dimensional stability, heat resistance, and the like.

  When manufacturing a polyimide resin endless belt, as a method of applying a coating liquid to a core body, as a conventionally known technique, the tip of a dispenser (nozzle) is brought into contact with the surface of a rotated cylindrical core body, and the resin solution is dispensed from the dispenser. There is a method of supplying and applying (for example, see Patent Document 1). In this method, when a high-viscosity solution having a viscosity at 25 ° C. of about 1 to 1500 Pa · s was discharged, the solution was not sufficiently smoothed, and spiral streaks remained, which was not preferable.

Therefore, there is a method of smoothing the discharged solution with a blade (see, for example, Patent Document 2). FIG. 1 shows a schematic view of this method, in which (A) is a side view and (B) is a front view. In the figure, a resin solution 16 is held in a container 14 and sent out to a discharge port 15 by a pump 11. The solution 16 is discharged from the discharge port 15 onto the rotator 13 and flows down in a streak shape. However, the solution 16 is smoothed by the blade 12 pressed immediately downstream without leaving a spiral streak. 17 is formed. When the discharge port 15 is moved in the horizontal direction from one end of the core body to the other end as shown in FIG. 1B (from the left to the right in the figure) along with the application, the entire surface of the core body is applied. The horizontal movement speed of the discharge port 15 and the blade 12 is usually about 0.1 to 2.0 m / min. During application, since a resin solution exists between the rotating body 13 and the blade 12, they are not in direct contact with each other.
In this method, since the discharged solution is smoothed by a blade, the solution does not become a spiral streak, but has a disadvantage that it takes a long time to apply the solution to the entire surface of the core.

  For this problem, a coating film forming method is proposed in which coating is performed in a short time by supplying a coating liquid over the entire surface of the rotating body, and then scraped with a blade having the same length as the coating film (for example, a patent). Reference 3-6). Although these methods have improved the method of separating the blade from the coating film, there are some attempts to eliminate streaks (referred to as “separation lines” in the present application) that occur when the blade leaves the coating film. It was quite difficult to solve completely.

Further, although a method using a blade with a devised shape has been proposed (see, for example, Patent Document 7 or 8), the problem of the liquid separation line has not been solved, and further improvement has been demanded.
JP-A-9-85756 Japanese Patent Laid-Open No. 10-69183 Japanese Patent Laid-Open No. 2004-122012 JP 2004-160310 A JP 2004-181291 A JP 2004-202452 A Japanese Patent Laid-Open No. 10-69183 JP-A-10-69184

  Then, an object of this invention is to provide the coating-film formation method which prevented generation | occurrence | production of the liquid separation line at the time of smoothing with a braid | blade effectively, and the manufacturing method of an endless belt by this coating-film formation method.

The conventional problems can be achieved by the following present invention. That is, the present invention
<1> A coating film forming method of forming a coating film by flowing a coating solution down onto a rotating body and then smoothing with a blade, wherein the coating is uniformly applied to the coating width of the surface of the rotating body. The nozzle is capable of flowing the coating liquid, and the smoothing is performed by rotating the rotating body and rotating a blade narrower than the coating width against the coating liquid held on the surface of the rotating body. It is a coating-film formation method characterized by performing by moving to a body-axis direction.

  By using a nozzle that can uniformly apply the coating liquid at a high speed and performing smoothing while moving it with a narrow blade, the coating liquid can be pressed in a spiral shape. Since only the terminal part is separated, the generation of the liquid separation line can be suppressed and the coating film can be formed at a high speed.

  <2> A coating film forming method for forming a coating film by flowing a coating solution down onto a rotating body and then smoothing with a blade, wherein the rotating body is rotated and the rotating body is rotated. After the blade is pressed against the coating liquid held on the surface, the blade and the coating liquid held on the surface of the rotating body gradually move along the inclination in a state where the tip is inclined with respect to the axial direction of the rotating body. The method for forming a coating film is characterized in that it is performed by pulling the blade away from each other.

  Since the blade and the coating liquid are gradually separated from one side of the inclination by being separated in a state having an inclination, it is possible to effectively prevent the occurrence of a liquid separation line.

<3> The method for forming a coating film according to <2>, wherein the blade has a shape whose tip is inclined with respect to the axial direction of the rotating body.
<4> The above <3>, wherein a blade having a width equal to or larger than the coating width of the surface of the rotating body is used as the blade, and the blade is pressed over the entire coating width during the smoothing. It is a coating-film formation method of description.
<5> A blade having a width equal to or greater than the application width of the surface of the rotating body is used as the blade, and the smoothing is performed by rotating the rotating body and applying the coating liquid held on the surface of the rotating body. After pressing the blade over the entire area, the blade is rotated with one point as a fulcrum so that the blade tip is inclined with respect to the axis of the rotating body, and then held on the blade and the surface of the rotating body along the inclination. <2> The method for forming a coating film according to <2>, wherein the method is performed by separating the blade so that the coating liquid is gradually separated.
<6> Any one of the above <2> to <5>, wherein the coating is performed using a nozzle capable of uniformly flowing the coating liquid with respect to the coating width of the surface of the rotating body. It is the coating-film formation method of description.

<7> A coating film forming apparatus comprising: a rotating body; a nozzle for flowing and applying a coating liquid to the rotating body; and a blade for smoothing the applied coating liquid to form a coating film. The nozzle is a nozzle that uniformly flows the coating liquid with respect to the coating width of the surface of the rotating body, the blade has a width narrower than the coating width, and rotates the rotating body, and the blade rotates the rotating body. In the coating film forming apparatus, the smoothing is performed by moving in the axial direction of the rotating body while being pressed against the coating liquid held on the surface.
<8> A coating film forming apparatus comprising: a rotating body; a nozzle for flowing and applying a coating liquid to the rotating body; and a blade for smoothing the applied coating liquid to form a coating film. After rotating the rotating body and pressing the blade against the coating liquid held on the surface of the rotating body, the blade and the rotating body along the inclination with the tip inclined with respect to the axial direction of the rotating body In the coating film forming apparatus, the smoothing is performed by separating the blade so that the coating liquid held on the surface is gradually separated.
<9> The coating film forming apparatus according to <8>, wherein the blade has a shape in which a tip is inclined with respect to the rotating body axial direction.
<10> The blade has a width equal to or larger than the application width of the surface of the rotating body, and the smoothing is performed by rotating the rotating body and applying the coating liquid held on the surface of the rotating body. After pressing the blade over the entire area, the blade is rotated with one point as a fulcrum so that the blade tip is inclined with respect to the axis of the rotating body, and then held on the blade and the surface of the rotating body along the inclination. The coating film forming apparatus according to <8>, wherein the coating is performed by separating the blade so that the coating liquid is gradually separated.

  <11> After forming a coating film of the film-forming resin solution on the cylindrical core body by the coating film forming method according to any one of <1> to <6>, a resin film is formed by heating, A method for producing an endless belt, wherein the resin film is extracted from a core.

  ADVANTAGE OF THE INVENTION According to this invention, the coating-film formation method which effectively prevented generation | occurrence | production of the liquid separation line at the time of smoothing with a braid | blade, and the manufacturing method of an endless belt by this coating-film formation method can be provided.

Hereinafter, the coating film forming method according to the three aspects of the present invention will be described in detail as examples.
(Coating film forming method of the first aspect)
The coating film forming method according to the first aspect of the present invention is a coating film forming method of forming a coating film by smoothing with a blade after applying a coating liquid to a rotating body and applying the coating liquid, The nozzle is capable of flowing the coating solution uniformly with respect to the coating width on the surface of the rotating body, and the smoothing is performed by rotating the rotating body and using a blade narrower than the coating width. It is characterized in that it is performed by moving in the direction of the axis of the rotating body while pressing against the coating liquid held on the surface.

Here, an example of a coating film forming apparatus used in the coating film forming method of the first aspect will be described with reference to FIG. FIG. 2 is a schematic view of the apparatus, in which (A) is a side view and (B) is a front view.
The coating liquid 26 in the container 24 is sent out to the discharge port 28 by the pump 21. The width of the discharge port 28 needs to be equal to or longer than the width (length in the axial direction) of the region where the coating liquid 26 is to be applied to the surface of the rotating body 23, that is, uniformly over the entire coating width. It must be able to be applied. Pressurized air may be injected into the container 24 to extrude the coating liquid 26. The coating liquid 26 flows down on the rotator 23 while rotating the rotator 23, and stops discharging at the point of just one rotation. In the coating liquid 26 adhering to the rotating body 23, the joint remains linearly in the axial direction, but this is smoothed by the blade 22. Smoothing can be achieved by pressing the blade 22 against the coating liquid 26 while rotating the rotator 23 and moving it horizontally from left to right in FIG. At that time, spiral streaks may remain, but the streaks are small and disappear when left for a while, and a uniform coating film 27 is formed.

  As a smoothing condition, the rotational speed of the rotating body is preferably 5 to 300 rpm, and the horizontal movement speed of the blade can be made faster than the conventional method (the method described in FIG. 1). 0 m / min is preferred. During smoothing, since the coating film 26 exists between the rotating body 23 and the blade 22, they do not come into direct contact with each other. The blade is preferably made of a metal such as stainless steel or brass, or an elastic material such as fluororesin or polyethylene, and is preferably a plate having a thickness of 0.05 to 1 mm. The width needs to be at least wider than the pitch (horizontal movement speed / rotating body rotation speed), but a streak may remain even if it is too wide, and is preferably not more than twice the pitch.

The pump (liquid feed pump) 21 is preferably a MONO pump capable of discharging a constant amount without interruption. This pump is a rotary displacement type single-shaft eccentric screw pump, and the internal thread portion of the elastic material and the metallic external thread portion are fitted with high precision inside the pump to enable a constant volume movement. Therefore, since there is no pulsation and no mechanical stress is applied to the solution itself, the solution material is not denatured, aggregated or solidified, and air bubbles are not mixed. The advantage of this pump is that it can handle a wide range of solution viscosities, and the flow rate can be freely controlled by controlling the rotational speed of the male screw shaft. The film thickness t of the coating film is 30 μm ≦ t ≦ 150 μm. It is possible to easily control the range. The film thickness of the coating film is determined by the discharge amount of the solution.
Furthermore, in order to supply the solution from the container 4 to the mono pump 1, another mono pump may be installed. The pump employs a pump having a higher supply capacity than the MONO pump 1 and supplies a larger amount than the discharge amount of the MONO pump 1.

  When the non-application area 23B is provided at both ends of the rotator 23, the coating liquid 26 does not exist there, so the blade 22 directly contacts the rotator 23 and the surface is damaged or the tip of the blade 22 is Damage such as wear is likely to occur. In that case, you may make it stick out the blade 22 only to the presence part (application area | region) of a coating liquid. As the method, there are a method of moving the blade 22 back and forth or up and down, a method of rotating the fixed end of the blade 22 and the like so that the distance of the blade 22 to the rotating body 23 changes. Moreover, you may combine them.

The coating film forming method according to the second and third aspects of the present invention is a coating film forming method for forming a coating film by flowing a coating solution onto a rotating body and then applying the coating solution to a rotating body to form a coating film. After rotating the rotating body and pressing the blade against the coating liquid held on the surface of the rotating body, the blade is moved along the inclination with the tip inclined to the axial direction of the rotating body. And the coating liquid held on the surface of the rotating body is separated by gradually separating the blade.
Hereinafter, the coating film forming method will be described in detail with two examples.

(Method for forming coating film of second aspect)
The coating film forming method according to the second aspect of the present invention is a coating film forming method for forming a coating film by flowing a coating solution down onto a rotating body and then smoothing it with a blade. Using a tip whose shape is inclined with respect to the rotating body axial direction, and after smoothing, rotating the rotating body and pressing the blade against the coating liquid held on the surface of the rotating body, The blade is pulled apart so that the blade and the coating liquid held on the surface of the rotating body are gradually separated along the inclination.
In the coating film forming method of the second aspect, a blade having a width equal to or larger than the coating width of the rotating body surface is used as the blade, and the blade is pushed over the entire coating width during the smoothing. It is also preferable to apply the coating, and it is also preferable to perform the coating using a nozzle capable of flowing the coating solution uniformly over the coating width of the surface of the rotating body.

Here, an example of a coating film forming apparatus used in the coating film forming method of the second aspect will be described with reference to FIG. FIG. 3 is a schematic view of the apparatus, in which (A) is a side view and (B) is a front view.
The coating film forming apparatus shown in FIG. 3 is configured by applying a coating liquid 36 applied to the surface of the rotator 33 to a blade 39 having a shape in which the tip (end on the side in contact with the coating liquid) is inclined with respect to the axis of the rotator. Is a device for smoothing and obtaining a coating film. Here, the shape of the tip portion of the blade 39 may be linear or curved as long as it has an inclination over the entire range, but it is easy to apply a constant pressure. From the viewpoint of being able to achieve this, those having a linear inclination as shown in FIG. Further, the angle of inclination with respect to the rotating body axis direction in the case of having a linear inclination is preferably 10 to 30 °, and preferably 15 to 25 ° from the viewpoint of shortening the time required for smoothing. Particularly preferred. The width of the blade (the length in the direction parallel to the axis of the rotating body) is not particularly limited, but from the viewpoint of shortening the time required for smoothing, the width of the blade should be greater than the coating width on the surface of the rotating body. preferable. In addition, about the material and thickness of a braid | blade, it is the same as that of the coating-film formation method of a 1st aspect.

  Further, the coating apparatus for applying the coating liquid 36 to the surface of the rotating body 33 is not particularly limited, and the coating liquid is uniformly applied to the coating width of the rotating body surface as shown in FIG. An apparatus having a nozzle that can flow down (that is, an apparatus similar to that used in the coating film forming method of the first aspect) or an apparatus as shown in FIG. 1 can be used. The former is particularly preferable from the viewpoint of shortening the time required for coating.

Next, the operation of the coating film forming apparatus shown in FIG. 3 will be described.
After the coating liquid 36 is applied to the surface of the rotator 33 by the coating method in the first coating film forming method, a blade 39 having a width equal to or larger than the application width of the rotator surface shown in FIG. The coating liquid 36 held on the surface is pressed, and then the coating film is smoothed by being pulled away to the fixed end side of the blade 39 (pointing to the reverse end direction of the tip, hereinafter referred to as “front side”). At this time, since the blade 39 gradually moves away from the coating liquid 36 along the inclination of the tip, it is possible to suppress the generation of a liquid separation line. When the blade 39 has a width less than the coating width on the surface of the rotator, as in the first coating film forming method, the blade 39 is moved horizontally with respect to the axis of the rotator 33 and smoothed. Similarly, pull it away from you.

(Method for forming coating film of third aspect)
A coating film forming method according to a third aspect of the present invention is a coating film forming method for forming a coating film by flowing a coating solution onto a rotating body and then smoothing it with a blade. Using a material having a width equal to or greater than the application width of the surface of the rotating body, and smoothing, the rotating body is rotated and the blade is pressed over the entire coating width of the coating liquid held on the surface of the rotating body. After that, the blade is rotated with one point as a fulcrum so that the blade tip is inclined with respect to the axis of the rotating body, and then the blade and the coating liquid held on the surface of the rotating body gradually move along the inclination. This is done by pulling the blade away.

Here, an example of a coating film forming apparatus used in the coating film forming method of the third aspect will be described with reference to FIG. FIG. 4 shows a schematic view of the apparatus, (A) is a side view, (B) is a front view, and (C) and (E) are front views showing stages of smoothing operation. (D) is a side view in (E).
The coating film forming apparatus shown in FIG. 4 is an apparatus that obtains a coating film by smoothing the coating liquid 46 applied to the surface of the rotating body 43 with a blade 49 having a width equal to or larger than the coating width of the rotating body surface. The blade 49 is not particularly limited as long as it has a width equal to or greater than the coating width. However, when the blade 49 is rotated with one point as a fulcrum as will be described later, the tip end of the blade 49 (FIG. 4C). It is more preferable that the portion K) has a width that does not contact the coating liquid. In addition, the material and thickness of the blade 49 are the same as those of the coating film forming method of the first aspect, and the coating apparatus of the first aspect is also applied to the coating apparatus that applies the coating liquid 46 to the surface of the rotating body 43. It is the same as the method.

Next, the operation of the coating film forming apparatus shown in FIG. 4 will be described.
After applying the coating liquid 46 to the surface of the rotating body 43 by the coating method in the first coating film forming method, the blade 49 is applied to the coating liquid 46 held on the surface of the rotating body 43 as shown in FIG. Then, as shown in FIG. 4C, the blade 49 is rotated around the fulcrum 50 so that the tip of the blade 49 is inclined with respect to the axial direction of the rotating body 43. At that time, as shown in FIG. 4C, a part of the tip of the blade 49 may be separated from the coating liquid 46, and the tip is gradually separated by the rotational movement, so that the generation of the liquid separation line can be suppressed. it can. In addition, as an angle of the inclination with respect to the axial direction of the said rotary body 43, 10-30 degrees is preferable from a viewpoint of shortening the time which smoothing requires, and 15-25 degrees is especially preferable.
After the blade 49 is rotated to a desired angle, the coating film is smoothed by pulling away from the front side. Also at this time, since the blade 49 gradually moves away from the coating liquid 46 along the inclination of the tip, it is possible to suppress the occurrence of a liquid separation line.
The position at which the fulcrum 50 is provided is not particularly limited, but is preferably on the front side of the blade 49 and near both ends in the width direction.
After smoothing, the adhering coating liquid 46 may remain on the surface of the blade 49. However, if the drying of the coating liquid is slow, the next operation may be performed as it is, and the drying of the coating liquid is fast. It is preferable to wipe off lightly.

In the coating film forming method according to the first to third aspects, in order to prevent damage to the non-application area of the rotating body and the blade, it is possible to apply the adhesive by attaching an adhesive tape to the rotating body.
Hereinafter, a method of performing application in a state where an adhesive tape is attached to a rotating body in a conventional application method will be described with reference to FIG. FIG. 5 is a schematic view of the coating apparatus, where (A) is a side view and (B) is a front view.
In the figure, the coating liquid 6 is held in the container 4, and the coating liquid 6 is sequentially sent out to the pump 1. Pressurized air may be injected into the container 4 to push out the coating liquid 6, in which case a pump may not be necessary. Next, the rotating body 3 is fixed and rotated by the rotating body holding center 10, and the coating liquid 6 is discharged from the nozzle 5 onto the rotating body 3 and moved horizontally in the direction of the rotation end axis. The discharged coating liquid 6 flows out in a streak shape, but immediately after adhering to the rotating body 3, it is smoothed by the blade 2 and a coating film 7 is formed. As the nozzle 5 is applied and moved horizontally from one end to the other end of the rotating body 3 as shown in FIG. 5B (from left to right in the figure), it can be applied over the entire surface of the rotating body 3. . When the application is completed, the discharge of the coating liquid 6 is completed, and the blade 2 is pulled away to the front side.

During application, since the coating liquid 6 exists between the rotating body 3 and the blade 2, they do not come into direct contact with each other. However, since the coating liquid 6 does not exist in the non-applied portions 3B at both ends of the rotating body. The two may come into direct contact with each other, and the surface of the rotating body 3 may be damaged, or damage such as wear of the tip of the blade 2 may occur.
Therefore, the adhesive tape 8 is affixed to both ends of the rotating body 3, the blade 2 is pushed out toward the adhesive tape 8 at the start of application, and then the above damage is effectively prevented by discharging. Can do. At this time, the position of the blade 2 with respect to the rotating body 3 is adjusted, and at the end of application, the discharge is finished and the blade 2 is pulled down on the adhesive tape 8.

  The adhesive tape is a resin such as Teflon (registered trademark), polyester, or fluorine, and the width is preferably about 100 to 120% with respect to the width of the blade, and the thickness is preferably about 0.08 mm. It is preferable that the adhesive tape 8 is wound around the circumference at both ends of the application start position and the end position of the rotating body 3 with a length of about 100 to 120% of the circumference.

  The film thickness of the coating film 7 is determined by the discharge amount of the coating liquid 6, and therefore, it is preferable to make the discharge amount constant during application. The discharge of the coating liquid 6 may be a method of extruding from the container 4 with pressurized air. However, in order to ensure the quantification, it is preferable to supply the coating liquid 6 with the pump 1. As the pump 1, the above-mentioned Mono pump capable of discharging a constant amount without interruption is particularly preferable.

In the production of the endless belt described later, the coating film is heated and dried after the coating film is formed. In particular, when the coating solution is a polyimide precursor solution, if the solvent is excessively removed from the coating film, the coating film does not yet retain its strength, and thus cracking is likely to occur when the adhesive tape is peeled off. Therefore, it is preferable to leave the solvent to some extent (15 to 45% by mass in the polyimide precursor film).
By peeling off the adhesive tape after drying by heating, a gap with the core can be formed at the end of the polyimide precursor film.

(Endless belt manufacturing method)
When manufacturing an endless belt made of polyimide resin or polyamide-imide resin by the above-mentioned coating film forming method, after coating the film forming resin solution on the cylindrical core body, the core body is moved to a drying device and heated. And an endless belt can be obtained by removing from the core.

In particular, when an endless belt made of polyimide resin is produced, drying is performed after forming a coating film of a film-forming resin solution, but it is preferable to rotate the core so that the coating film does not hang downward. The rotation speed is preferably about 1 to 60 rpm, and the heating condition is preferably 90 to 170 ° C. for 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.
Moreover, a polyimide resin is formed by the polyimide precursor film undergoing a condensation reaction through a heating and firing step. The firing conditions are 250 to 450 ° C., preferably around 300 to 350 ° C., and the temperature may be raised stepwise for 20 to 60 minutes. In this step, since the film is fixed, the core body may be oriented in any direction, and may not be rotated during heating.
When the solution is a polyamideimide resin solution, a film can be obtained only by drying the solvent.

When the endless belt is used as a transfer member or a contact charging member in the image forming apparatus, it is preferable to disperse a conductive substance in the film forming resin 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.

  In order to use the endless belt as a fixing member in the image forming apparatus, it is preferable to form a fluororesin layer that is non-adhesive to toner on the surface of the polyimide resin. The material is preferably a fluorine-based resin such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP). In addition, carbon powder may be dispersed in the non-adhesive resin layer in order to improve durability and electrostatic offset.

  In order to form the fluorine-based resin layer, a method in which the aqueous dispersion is applied to the surface of the polyimide resin and baked is preferable. Moreover, when the adhesiveness of a fluorine-type resin layer is insufficient, there exists a method of apply | coating and forming a primer layer beforehand on the polyimide resin surface as needed.

  In order to form a fluorine-based resin layer on the surface of the polyimide resin, a heated polyimide resin (belt) may be formed on the surface of the core and then applied, but a polyimide precursor solution may be applied. After drying the solvent or without completely drying the solvent, the fluorinated resin dispersion may be applied and then heated to simultaneously perform the imide conversion completion reaction and the calcination treatment of the fluorinated resin layer. In this case, the adhesiveness of the fluororesin layer may be strengthened even without the primer layer.

  In the case of the fixing belt, the polyimide resin layer preferably has a thickness of 25 to 100 μm, and the fluororesin layer preferably has a thickness of 10 to 40 μm.

Example 1
Using a coating apparatus shown in FIG. 2, a polyimide precursor solution (trade name: Uimide, manufactured by Unitika) having a viscosity of about 100 Pa · s at 25 ° C. is applied to a rotating body made of an aluminum cylinder having a diameter of 30 mm and a length of 500 mm. It was applied with a width of 400 mm. Specifically, the MONO pump 1 was connected to the container 4 containing 400 ml of the polyimide precursor solution, and the coating was performed by discharging 23 ml during one rotation at a rotation speed of the rotating body of 10 rpm. As a result, a coating film having an average of 600 μm was formed, but streaks were formed at the start and end of discharge.

  Next, as a blade 22, a stainless steel plate having a thickness of 0.1 mm processed to a width of 8 mm and a length of 50 mm was used. As shown in FIG. Then, the blade was moved at a speed of 360 mm / min in the axial direction of the rotating body, and the blade was pulled down by 50 mm toward the end of the coating so that it did not come into direct contact with the surface of the rotating body. Thereby, the streaks on the coating film surface disappeared and a smooth coating film was formed.

Thereafter, while rotating the core at 10 rpm, the core was placed in a heating device at 120 ° C. and dried for 45 minutes. Next, the core was made vertical and heated at 190 ° C. for 10 minutes, 250 ° C. for 30 minutes, and 320 ° C. for 30 minutes to form a polyimide resin film. After the core cooled to room temperature, the coating was removed to obtain an endless belt.
The obtained endless belt had an average film thickness of 80 μm, variation (difference between the maximum value and the minimum value) of 4 μm or less, and was a smooth film without streaks.

(Example 2)
In the same manner as in Example 1, the polyimide precursor solution was applied to the rotating body.
Next, as the blade 32, a stainless steel plate having a thickness of 0.1 mm as shown in FIG. 3 is 400 mm wide, the short side (left side in FIG. 3B) is 50 mm long, and the long side (right side in FIG. 3B). ) To smooth the coating by pressing the blade 32 against the coating film and increasing the rotational speed of the rotating body to 120 rpm using a machined length of 80 mm and an inclination angle of 20 ° with respect to the axis of the rotating body After contacting the blade for 5 seconds, the blade was pulled down 90 mm at 5 mm / s.
No liquid separation line was generated, and a smooth coating film was formed.

(Example 3)
In the same manner as in Example 2, the polyimide precursor solution was applied to the rotating body.
Next, as the blade 49, a stainless steel plate having a thickness of 0.1 mm as shown in FIG. 4 processed to a width of 400 mm and a length of 80 mm was used, and the rotational speed of the rotating body was increased to 120 rpm. In order to smooth the coating film pressed against the blade, the blade is brought into contact with the blade for 5 seconds, and then horizontally lowered until the inclination with respect to the axis of the rotating body becomes an angle of 20 ° around the fulcrum 50 (that is, the blade 49 is rotated by 20 °). Then, the blade 49 was pulled away to the front side of 120 mm at 5 mm / s.
No liquid separation line was generated, and a smooth coating film was formed.

(A) is a side view which shows the conventional coating-film formation apparatus, (B) is a front view in (A). (A) is a side view which shows the coating-film formation apparatus used for the coating-film formation method of the 1st aspect which concerns on this invention, (B) is a front view in (A). (A) is a side view which shows the coating-film formation apparatus used for the coating-film formation method of the 2nd aspect which concerns on this invention, (B) is a front view in (A). (A) is a side view which shows the coating-film formation apparatus used for the coating-film formation method of the 3rd aspect which concerns on this invention, (B) is a front view in (A). Further, (C) and (E) are front views showing stages of the smoothing operation, and (D) is a side view in (E). (A) is a side view which shows the image forming apparatus which affixes an adhesive tape to a rotary body, and performs application | coating, (B) is a front view in (A).

Explanation of symbols

1, 11, 21, 31, 41 Pump 2, 12, 22, 39, 49 Blade 3, 13, 23, 33, 43 Rotating body 3B, 23B Non-application area 4, 14, 24, 34, 44 Container 15, 28 , 38, 48 Discharge port 6, 16, 26, 36, 46 Resin solution 7, 17, 27, 37, 47 Coating 8 Adhesive tape 10 Rotating body holding center 50 Support point

Claims (5)

A coating film forming method for forming a coating film by smoothing with a blade after applying the coating liquid flowing down to a rotating body,
The application is performed using a nozzle that can uniformly flow down the coating width of the rotating body surface,
The smoothing is performed by rotating the rotating body and moving the blade narrower than the coating width in the axial direction of the rotating body while pressing the blade against the coating liquid held on the surface of the rotating body. Film forming method. A coating film forming method for forming a coating film by smoothing with a blade after applying the coating liquid flowing down to a rotating body,
The smoothing is performed by rotating the rotating body and pressing the blade against the coating liquid held on the surface of the rotating body, with the tip inclined with respect to the rotating body axial direction. A method of forming a coating film, comprising: separating the blade so that the blade and the coating liquid held on the surface of the rotating body are gradually separated from each other. A coating film forming apparatus comprising: a rotating body; a nozzle for flowing and applying a coating liquid to the rotating body; and a blade for smoothing the applied coating liquid to form a coating film.
The nozzle is a nozzle for uniformly flowing down the coating liquid with respect to the coating width of the rotating body surface;
The blade has a width narrower than the application width;
The coating film forming apparatus characterized by performing the smoothing by rotating the rotating body and moving the blade in the axial direction of the rotating body while pressing the blade against the coating liquid held on the surface of the rotating body. A coating film forming apparatus comprising: a rotating body; a nozzle for flowing and applying a coating liquid to the rotating body; and a blade for smoothing the applied coating liquid to form a coating film.
After rotating the rotating body and pressing the blade against the coating liquid held on the surface of the rotating body, the blade and the rotation along the inclination with the tip inclined with respect to the axial direction of the rotating body. A coating film forming apparatus, wherein the smoothing is performed by pulling a blade apart so that the coating liquid held on the body surface is gradually separated.   A coating film of a film forming resin solution is formed on a cylindrical core body by the coating film forming method according to claim 1 or 2, and then heated to form a resin film, and the resin film is extracted from the core body. A method for producing an endless belt.

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