JP7252012B2 - Coating device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating apparatus that continuously coats a long film conveyed by roll-to-roll to form a circuit pattern with high precision.

In the past, techniques such as sputtering, CVD, and photolithography were known for forming circuit patterns, but in recent years, in order to contribute to low cost, energy saving, and resource saving, circuit patterns using various printing techniques have been developed. formation technology (printed electronics) is attracting attention. Above all, after a metal ink is dropped from an inkjet nozzle onto a substrate to form a circuit pattern, an insulating layer is dropped from the inkjet nozzle onto the substrate, and then a metal ink is dropped from the inkjet nozzle onto the substrate to form a circuit. Techniques have been developed for forming multilayer circuit patterns in a pattern-forming manner.

Further, in order to apply a coating liquid to a long film, from the viewpoint of production efficiency, the long film is often conveyed roll-to-roll for continuous coating.

Patent Literature 1 describes a manufacturing apparatus that continuously applies and dries a film conveyed by roll-to-roll.

Patent Document 1: Japanese Patent Application No. 2005-030682

However, in the manufacturing apparatus having the structure of Patent Document 1, there is a problem that a circuit pattern cannot be formed on the film with high positional accuracy when meandering occurs in the film during roll-to-roll transport. Here, if the film is not transported and the coating unit is moved to apply the coating during the coating process, i.e., the so-called intermittent transport, the length of time the film stays in the drying unit will differ depending on the position of the film. Therefore, uneven drying may occur. In addition, there is a risk that the film will be deformed due to thermal elongation at the front and rear boundaries of the drying unit.

In view of the above problems, it is an object of the present invention to provide a coating apparatus that can accurately apply a coating liquid to a long film while continuously conveying the film in a roll-to-roll manner and then dry the film.

In order to solve the above problems, the coating apparatus of the present invention includes a delivery roll that is wound with a strip-shaped base material and that delivers the base material by rotating; and a base material that is sent out from the delivery roll by rotating. A winding roll that winds up the base material, an application unit that is positioned between the delivery roll and the winding roll in the conveyance path of the base material, fixes the base material and applies a coating liquid to the base material, and A drying unit positioned between the coating unit and the take-up roll in the transport path and drying the coating liquid on the substrate being transported at a constant speed, and the coating unit and the drying unit in the transport path of the substrate and between the delivery roll and the application section, and a first buffer section that maintains a state in which the substrate is folded back such that the length of the substrate forming that state is variable. and a second buffer portion that maintains a state in which the substrate is folded back such that the length of the substrate forming the state is variable , and in the coating operation, the substrate in the coating portion is fixed, while the drying section continues to convey the substrate by pulling out the substrate so as to consume the length of the folded portion of the substrate in the first buffer section. do.

According to the coating apparatus of the present invention, the coating section can apply the coating liquid to the base material while fixing the base material, so that the coating liquid can be applied to the base material with high precision, and at the same time, it has the first buffer section. Because the coating liquid can be dried in the drying section without stopping the conveyance of the substrate, uneven drying and deformation of the film due to heat can be prevented.

Further, the first buffer section preferably has a bottom surface portion and side wall portions forming a substrate holding space, which is a space for holding the substrate, and decompression means for decompressing the substrate holding space.

By doing so, it is possible to maintain the folded state of the base material without flapping the base material.

Further, the drying unit has a drying furnace for drying the coating liquid on the base material, and a driving roll provided immediately upstream and immediately downstream of the drying furnace in the transport path of the base material, and the driving roll may be in contact with the base material and block the tension of the base material on the upstream side and the downstream side of the portion where the driving roll contacts the base material.

By doing so, the base material is in a bent state in the drying oven, and it is possible to prevent the base material from stretching due to heating.

The drying section may have a sensor for measuring or detecting deflection of the base material provided between the drying oven and the drive roll.

By doing so, proper substrate deflection can be maintained.

In addition, the coating unit has a grip feeder that grips the lateral end of the substrate and pulls the substrate to move it, and the moving speed of the grip feeder is the delivery speed of the substrate by the delivery roll. and faster than the take-up speed of the base material by the take-up roll.

By doing so, the substrate can be transported quickly and accurately, and the time required for transport during the entire coating process can be relatively shortened.

With the coating apparatus of the present invention, a long film can be accurately coated with a coating liquid and dried while being continuously conveyed in a roll-to-roll manner.

It is a figure explaining the coating device in this invention. It is a figure showing the movement in coating operation of the coating device in this invention. It is a figure showing the motion at the time of interruption of the coating operation|movement of the coating device in this invention. It is a figure explaining the coating device of other embodiment in this invention.

A coating apparatus of the present invention will be described with reference to FIG.

The coating device 1 transports a belt-shaped base material W in one direction by a roll-to-roll system, and prints a TFT circuit pattern or the like on the base material W. It has a take-up roll 3, and these are arranged side by side on the transport path of the substrate W in this order. In this coating device 1 , the substrate W delivered from the delivery roll 2 is wound up by the take-up roll 3 and transported. The substrate W sent out from the delivery roll 2 is coated with the coating liquid in the coating section 10 and dried in the drying section 20 before being wound up by the take-up roll 3 . Thereby, it is possible to obtain the base material W on which the predetermined circuit pattern is printed.

In addition, in the present embodiment, a buffer section 30 is arranged between the coating section 10 and the drying section 20 in the conveying path of the base material W, and a buffer section 30 is arranged between the delivery roll 2 and the coating section 10. The portion 40 is arranged, and the folded back of the substrate W is formed and maintained in the buffer portion 30 and the buffer portion 40 .

In this description, the vertical direction is referred to as the Z-axis direction, the width direction of the substrate W among the horizontal directions is referred to as the Y-axis direction, and the horizontal direction perpendicular to the Y-axis direction, that is, the transport direction of the substrate W is referred to as the X-axis direction. called the axial direction.

The delivery roll 2 is for supplying the substrate W to the downstream side. The feed roll 2 is driven and controlled to rotate by a control device (not shown), so that the base material W can be fed out at a predetermined speed.

Here, the base material W is a strip-shaped workpiece, and for example, a transparent PET film or the like is used.

The take-up roll 3 takes up the supplied base material W. As shown in FIG. The take-up roll 3, like the delivery roll 2, can take up the base material W by driving and controlling its rotation by a control device (not shown).

The coating unit 10 is positioned on the conveying path of the base material W by the delivery roll 2 and the take-up roll 3, and applies a coating liquid to the base material W. In this embodiment, a predetermined pattern is formed by an inkjet method. A predetermined coating pattern is formed on the upper surface (coating surface) of the base material W by discharging droplets of the coating liquid according to the shape (for example, the shape of the TFT circuit pattern).

The coating section 10 has a suction stage 11 , a coating head 12 , an imaging section 13 and a grip feeder 14 .

The adsorption stage 11 adsorbs and fixes the substrate W, and the surface facing the substrate W is substantially flat and has openings of a plurality of suction holes. This suction hole is connected to a decompressing means (not shown) such as a vacuum pump. By operating this decompression means, the gas is sucked from the suction holes, and the base material W is adsorbed and fixed.

Further, the rolls (called lift-up rolls) immediately upstream and downstream of the adsorption stage 11 are attached to a vertical (Z-axis direction) moving means (not shown), and the substrate W is moved in the coating section 10. While being conveyed, the lift-up rolls are lifted by the moving means to separate the substrate W from the adsorption stage 11, thereby preventing interference with the substrate W being conveyed.

The coating head 12 ejects a coating liquid by an inkjet method, and the surface facing the base material W is substantially flat and has openings of a plurality of ejection holes. The discharge holes are connected to a tank (not shown) in which the coating liquid is stored via a pipe, and each discharge hole is filled with the coating liquid.

Further, each ejection hole is provided with a drive partition made up of a piezo actuator, and liquid droplets are ejected from the opening of the ejection hole by operating the drive partition according to a command from a control unit (not shown).

In addition, the plurality of ejection holes are linearly arranged at regular intervals. Further, the coating head 12 is attached to a rotating means having a rotation axis in the Z-axis direction. By adjusting the inclination in the arrangement direction, the interval in the Y-axis direction of each discharge hole is adjusted.

Here, the coating head 12 is attached to scanning direction moving means (not shown) that moves the coating head 12 in the longitudinal direction of the substrate W (X-axis direction in the coating section 10).

In this description, the movement of the coating head 12 in the X-axis direction by the scanning direction moving means during the coating operation is called "scanning".

By ejecting liquid droplets while the coating head 12 scans above the base material W fixed by the suction stage 11, the dimension in the X-axis direction is the moving distance of the coating head 12 due to this scanning (referred to as scanning distance). , and the dimension in the Y-axis direction is the same as the dimension in the Y-axis direction of the region in which the plurality of ejection holes are arranged.

Further, in this embodiment, the coating head 12 is attached to shift direction moving means (not shown) that moves the coating head 12 in the width direction of the substrate W (Y-axis direction). After the application head 12 performs a series of application operations while scanning, the application head 12 is moved in the Y-axis direction by the shift direction moving means, and then the application head 12 performs a series of application operations while scanning again. In this description, the movement of the coating head 12 in the Y-axis direction after performing a series of coating operations is referred to as "shifting". Note that the coating liquid is not discharged from the coating head 12 during the shift operation.

By repeating scanning and shifting in this manner, a coating pattern having a dimension in the Y-axis direction that exceeds the dimension in the Y-axis direction of the region where the plurality of ejection holes are arranged is formed on the coating surface of the substrate W. .

The imaging unit 13 is one or a plurality of CCD cameras in this embodiment, and is attached to moving means (not shown) that moves the imaging unit 13 in the X-axis direction and the Y-axis direction.

The image capturing unit 13 captures an image of a characteristic mark (alignment mark) formed on the coating surface of the substrate W fixed by the suction stage 11, and a control unit (not shown) analyzes the coordinates of this alignment mark. For example, the controller can grasp the position of the substrate W by analyzing the coordinates of the four alignment marks on the substrate W fixed by the suction stage 11 .

The substrate W transported by roll-to-roll is not necessarily transported in a predetermined direction with high precision, and is transported with a considerable meandering motion. Therefore, when the substrate W is fixed by the suction stage 11, there is a possibility that the substrate W is fixed at a position shifted from a predetermined position. , the deviation of the fixing position of the base material W can be grasped.

Then, before the coating head 12 applies the coating liquid, the deviation of the fixing position of the base material W is grasped, and reflected in the coating operation, for example, by correcting the coating coordinates. A coating pattern can be formed on the coating surface of the base material W with good positional accuracy even if the coating is carried out.

The grip feeder 14 has an upper member that contacts the coating surface side of the base material W and a lower member that contacts the lower surface side of the base material W, and both the upper and lower members contact the base material W at the same time. The substrate W is held therebetween.

The region of the base material W held by the grip feeder 14 is the end portion in the width direction (lateral direction) of the base material W, and is a range in which the coating pattern does not exist, and the grip feeder 14 destroys the coating pattern. there is nothing to do.

Further, the grip feeder 14 has moving means (not shown) for moving both members in the X-axis direction, and both members move in the X-axis direction while holding the ends of the base material W in the short direction. By doing so, the substrate W can be pulled and moved. By setting the moving distance of both members at this time to be the same as the scanning distance of the coating head 12, the base material W can be advanced by exactly one coating pattern, and the coating pattern formed by the preceding and following coating operations can be changed. It can be formed without gaps and overlaps. In addition, since such a grip feeder 14 is provided, the substrate W can be conveyed at once with high accuracy in the coating section 10 .

The drying section 20 is located downstream of the coating section 10 in the conveying path of the substrate W, and heats and dries the coating pattern on the substrate W with hot air. 23 and a sensor 24 .

The drying oven 21 is a box-like device having a space inside for the substrate W to pass through and openings serving as an entrance and an exit for the substrate W. As shown in FIG. A surface forming the inner space of the drying oven 21 and facing the upper surface of the base material W is provided with a plurality of ventilation holes for blowing out hot air, and is the coating surface on which the coating pattern of the base material W is formed. , hot air is blown as indicated by the arrow in FIG. This accelerates volatilization of the solvent in the coating pattern, and dries and cures the coating pattern.

Here, the substrate W is conveyed in the drying furnace 21 at a constant speed in order to prevent unevenness in drying by the drying furnace 21 and deformation of the film due to heat over the longitudinal direction of the substrate W. As shown in FIG. As a result, the time during which the hot air hits the entire substrate W becomes uniform.

In the present embodiment, the drying furnace 21 applies hot air to the base material W. However, if the base material W flutters due to the hot air, the drying means irradiates the base material W with infrared rays instead of the hot air. can be

The drive roll 22 and the drive roll 23 are roll bodies rotated by a drive source (not shown), and are in contact with the coating surface of the base material W, and sandwich the base material W with free rolls that support the base material W from below. As a result, the tension of the base material W can be cut off on the upstream side and the downstream side of the portion where the drive roll 22 contacts the base material W in the conveyance path of the base material W, and the upstream side and the downstream side of the drive roll 22 can be cut off. and can independently control the tension of the substrate W. Similarly, the tension of the substrate W can be interrupted on the upstream side and the downstream side of the portion where the drive roll 23 contacts the substrate W, and the substrate W can be prevented from being applied to the upstream side and the downstream side of the drive roll 23. Tension can be controlled independently.

The drive roll 22 is provided immediately upstream of the drying furnace 21 in the transport path of the base material W, and the drive roll 23 is provided immediately downstream of the drying furnace 21 in the transport path of the base material W, The transport speed and tension of the substrate W in the drying oven 21 depend on the rotational speeds of the drive rolls 22 and 23 .

The area where the drive roll 22 contacts the coating surface of the base material W in the Y-axis direction is the part where the coating pattern is not formed on both ends of the base material W in the Y-axis direction. cannot be destroyed.

Further, when the drive roll 23 comes into contact with the coating surface of the base material W, it is after the coating pattern has been cured by the drying oven 21. Therefore, the drive roll 23 can come into contact with the entire base material W in the Y-axis direction. I do not care. Further, like the driving roll 22, it may be brought into contact only with the portions where the application pattern is not formed on both ends of the substrate W in the Y-axis direction.

In this embodiment, the sensor 24 is a so-called reflection sensor that emits light toward the object to be measured and receives light reflected by the object to be measured. and the drive roll 22 and between the drying oven 21 and the drive roll 23, the height (position in the Z-axis direction) of the substrate W is measured.

When the base material W is heated in a stretched (excessive tension) state, the base material W is elongated and deformed. Therefore, in the drying furnace 21, the substrate W is transported in a slightly bent state as shown in FIG. Therefore, by measuring the height of the base material W with the sensor 24, the deflection of the base material W in the drying oven 21 is estimated, and the result is fed back to the rotation of the drive rolls 22 and 23. . If the base material W is stretched or flexed excessively and the amount of deflection of the base material W deviates from a predetermined range, a controller (not shown) adjusts the rotational speeds of the drive rolls 22 and 23, It is returned to a moderate amount of deflection.

The buffer section 30 is a device that is positioned between the coating section 10 and the drying section 20 in the conveying path of the base material W and causes the base material W to be folded back. In this description, the buffer section 30 positioned between the coating section 10 and the drying section 20 is called a first buffer section.

In this embodiment, the buffer section 30 is a box-like body having an opening upward, and has a bottom section 31 and side wall sections 32 . The base material W is accommodated in a space formed by the bottom surface portion 31 and the side wall portion 32 so as to form a fold. A space formed by the bottom surface portion 31 and the side wall portion 32 is called a substrate holding space.

The bottom portion 31 has a plurality of suction holes and is connected to a decompressing means (not shown) such as a vacuum pump. By operating the decompression means, gas is sucked from the suction holes as indicated by arrows in FIG. 1, and the substrate holding space is decompressed.

By depressurizing the substrate holding space in a state where the substrate W is accommodated in the substrate holding space, the folded back is formed and maintained while tension is applied to the substrate W. That is, by applying an appropriate tension to the base material W, the base material W can be stably run without bending.

The tension applied to the substrate W can be adjusted by adjusting the suction force of the decompression means.

A plurality of air ejection holes and a plurality of air suction holes are formed in the side wall portion 32 facing the surface of the accommodated substrate W, and air is ejected from the air ejection holes. Also, it may be configured such that air is sucked from the air suction hole. By doing so, a predetermined gap can be provided between the substrate W and the side wall portion 32 to separate them, and the substrate W can be prevented from coming into contact with the buffer portion 30 . Moreover, it is possible to make it difficult for the base material W to flutter in the buffer section 30 .

The buffer section 40 is a device that is positioned between the delivery roll 2 and the application section 10 in the transport path of the substrate W and causes the substrate W to be folded back. In this description, the buffer section 40 positioned between the delivery roll 2 and the coating section 10 is called a second buffer section.

Similar to the buffer section 30, the buffer section 40 is a box-shaped body having an opening on the top. are accommodated to form

The bottom portion 41 has a plurality of suction holes and is connected to a pressure reducing means (not shown) such as a vacuum pump. By operating the decompression means, gas is sucked from the suction holes as indicated by arrows in FIG. 1, and the substrate holding space is decompressed.

By depressurizing the substrate holding space in a state where the substrate W is accommodated in the substrate holding space, the folded back is formed and maintained while tension is applied to the substrate W. That is, by applying an appropriate tension to the base material W, the base material W can be stably run without bending.

The operation of the coating apparatus 1 having the above configuration will be described with reference to FIGS. 2 and 3. FIG. In particular, attention is paid to the movement of the base material W, and the locations where the base material W is moving are indicated by thick lines.

FIG. 2 is a diagram showing movement of the coating device 1 during the coating operation.

During the coating operation, the lift-up rolls of the coating unit 10 are lowered, and the coating head 12 scans while the suction stage 11 is holding the substrate W by suction, and the droplets 15 are ejected according to the shape of a predetermined pattern. A coating pattern is formed on the coating surface of the base material W by. At this time, the upper member and the lower member of the grip feeder 14 are separated from the substrate W.

In this manner, the suction stage 11 holds the substrate W by suction and the coating head 12 moves while performing coating. As described above, the coating pattern can be formed with high positional accuracy, but the coating operation is performed. The base material W does not move in the coating section 10 while being coated. On the other hand, in the drying section 20, the drive roll 22, the drive roll 23, and the take-up roll 3 are rotationally driven to prevent uneven drying and deformation of the film due to heat, and the substrate W continues to be conveyed at a constant speed. .

Here, in the present invention, a buffer section 30 is provided between the coating section 10 and the drying section 20 in order to simultaneously stop the conveyance of the substrate W in the coating section 10 and continuously convey the substrate W in the drying section 20 . is provided. As a result, while the conveyance of the base material W in the coating unit 10 is stopped, the base material W is pulled out from the buffer unit 30, and the accommodation length of the base material W in the buffer unit 30 is reduced (while consuming). , the transport of the substrate W in the drying section 20 can be continued.

Therefore, at the time when the adsorption stage 11 starts to adsorb the substrate W in order to perform coating, the length of the substrate W forming the folded portion in the buffer section 30 is at least It is necessary that the distance traveled by the base material W in the drying section 20 from the start of adsorption until the release of adsorption is equal to the distance. However, considering that there is a possibility that the time to suck and fix the base material W may be prolonged due to some problem in the coating operation, it is desirable that the buffer unit 30 has The length of the substrate W forming the folded back should be longer than the distance the substrate W advances in the drying section 20 from when the adsorption stage 11 starts to adsorb the substrate W to when the adsorption is released. preferable.

In addition, in the present embodiment, a buffer unit 40 is provided between the delivery roll 2 and the coating unit 10, and the delivery roll 2 can be used as the take-up roll even while the conveyance of the substrate W in the coating unit 10 is stopped. The base material W is sent out at a delivery speed equivalent to the winding speed of No. 3, and during that time, the accommodation length of the base material W in the buffer section 40 continues to increase.

FIG. 3 is a diagram showing the motion of the coating device 1 when the formation of a series of coating patterns is completed and the coating operation is interrupted.

At this time, the adsorption stage 11 in the application section 10 releases the adsorption of the substrate W and is separated from the substrate W. As shown in FIG. Then, the grip feeder 14 grips the substrate W and moves in the X-axis direction so that the area on the substrate W on which the next coating pattern is to be formed is positioned right above the suction stage 11 . The substrate W in 10 is moved.

Here, since the moving speed of the substrate W by the grip feeder 14 is faster than the feeding speed of the substrate W by the delivery roll 2 and the winding speed of the substrate W by the take-up roll 3, the substrate is fast and accurate. It can be conveyed well, and the time required for conveyance in the entire coating process can be relatively shortened.

On the other hand, since the base material W is pulled out from the buffer section 40, the accommodated length is shortened, but since the base material W is folded back in the buffer section 40, an excessive load is not applied to the delivery roll 2. On the other hand, if the buffer unit 40 were not provided between the delivery roll 2 and the coating unit 10, the delivery roll 2 would be a free roll without power, and the base material W would be delivered by the movement of the grip feeder 14. In a so-called stop-and-go mode in which the substrate W is pulled out from the roll 2, when the substrate W is transported at a high speed of, for example, 30 m/min, an inertial force acts when the substrate W is pulled out from the delivery roll 2, and the stop. There is a risk that the accuracy of the & Go operation will be degraded. Therefore, it is preferable that the buffer section 40 is provided as in the present embodiment.

Next, FIG. 4 shows a coating device 1 according to another embodiment of the present invention.

In the embodiment shown in FIG. 4, a liquid receiving portion 16 is provided. So-called flushing, in which droplets are continuously ejected, is performed in order to prevent the coating liquid from drying, solidifying, and clogging the ejection holes.

Here, when the flushing is performed during the formation of the coating pattern, it is necessary to restart the formation of the coating pattern from the point where the formation of the coating pattern was interrupted after the flushing. cannot be transported. On the other hand, since the buffer section 30 is provided as in the present invention, the conveyance of the substrate W in the drying section 20 can be continued while the conveyance of the substrate W in the coating section 10 is stopped.

With the coating apparatus described above, it is possible to accurately apply a coating liquid to a long film while continuously conveying the film in a roll-to-roll manner, and to dry the film.

Here, the coating apparatus of the present invention is not limited to the form described above, and may be of another form within the scope of the present invention. For example, in the above description, gas is sucked in the adsorption stage 11 as a means for fixing the substrate W in the coating section 10, but this is not the only option, and other fixing means may be employed. For example, electrostatic attraction may be used in which the substrate W is attracted and fixed by static electricity.

Further, the moving distance of the grip feeder 14 at one time may be shorter than the scanning distance of the coating head 12, or may be 1/n (n is an integer of 2 or more) of the scanning distance. In this case, the substrate W can be moved by the scanning distance by the grip feeder 14 continuously moving the substrate W n times.

Further, the mechanism for transporting the base material W in the coating section may be other than the grip feeder 14 . For example, a mechanism may be used in which the substrate W is gripped by a suction roll that attracts the substrate W, and the substrate W is sent out by rotating the suction roll. Alternatively, a mechanism may be used in which the base material W is nipped between the driving roll nip rolls and the base material W is sent out by rotationally driving the driving rolls.

Further, when the coating pattern is composed of a coating liquid that is cured by UV irradiation, the drying oven 21 is not a device for blowing hot air, but a device for irradiating the coated surface of the substrate W with UV rays.

In the above description, the drive roll 22 and the drive roll 23 are so-called nip rolls that sandwich the base material W with free rolls that support the base material W from below. A suction roll for attracting the base material W may be arranged so as to be in contact with the lower surface of the base material W. FIG. By contacting the lower surface of the base material W, it is possible to contact the entire base material W in the Y-axis direction without fear of destroying the coating pattern. Also, the drive roll 22 may be a nip roll, and the drive roll 23 may be a suction roll, which may be a combination of a nip roll and a suction roll.

In the above description, the buffer section 30 and the buffer section 40 are so-called air dancers that maintain the folded back of the base material W by reducing the pressure. The material W may be folded back. In this case, the dancer rolls used in the buffer section 30 between the coating section 10 and the drying section 20 contact only the both ends of the substrate W in the Y-axis direction so as not to contact the coating pattern. dancer roll.

Further, the sensor 24 is a set of sensors in which the issuing portion and the light receiving portion are arranged side by side in the Y-axis direction with the substrate W interposed therebetween, and can detect that the deflection amount of the film is within a predetermined range. can be

Reference Signs List 1 coating device 2 delivery roll 3 take-up roll 10 coating section 11 adsorption stage 12 coating head 13 imaging section 14 grip feeder 15 droplet 16 liquid receiving section 20 drying section 21 drying furnace 22 drive roll 23 drive roll 24 sensor 30 buffer section 31 Bottom part 32 Side wall part 40 Buffer part 41 Bottom part 42 Side wall part
W base material

Claims (6)

A delivery roll around which a belt-shaped base material is wound and which delivers the base material by rotating;
a take-up roll that rotates to take up the substrate delivered from the delivery roll;
a coating unit positioned between the delivery roll and the take-up roll in the substrate transport path to fix the substrate and apply a coating liquid to the substrate;
a drying unit located between the coating unit and the take-up roll in the transport path of the substrate and drying the coating liquid on the substrate being transported at a constant speed;
A first buffer unit positioned between the coating unit and the drying unit in the transport path of the substrate, and maintaining the folded state of the substrate such that the length of the substrate forming that state is variable. and,
a second buffer unit positioned between the delivery roll and the coating unit, and maintaining the folded state of the substrate such that the length of the substrate forming the state is variable;
with
During the coating operation, the base material is fixed in the coating part, while the base material is pulled out in the drying part so as to consume the length of the folded back part of the base material in the first buffer part. A coating device, characterized in that it continues to convey the material . 2. The coating apparatus according to claim 1, wherein said folded portion in said first buffer portion is formed by sagging of a substrate. 1. The first buffer section has a bottom surface portion and side wall portions forming a substrate holding space, which is a space for holding the substrate, and decompression means for decompressing the substrate holding space. Or the coating device according to 2. The drying unit has a drying furnace for drying the coating liquid on the substrate, and driving rolls provided immediately upstream and downstream of the drying furnace in the transport path of the substrate, and the driving rolls are: 4. The coating apparatus according to any one of claims 1 to 3, wherein the tension of the substrate is interrupted on the upstream side and the downstream side of the portion where the driving roll contacts the substrate. . 5. The coating apparatus according to claim 4, wherein the drying section has a sensor for measuring or detecting deflection of the base material provided between the drying oven and the drive roll. The application unit has a grip feeder that clamps the lateral end of the base material and pulls and moves the base material. 6. The coating apparatus according to any one of claims 1 to 5, wherein the winding speed of the substrate is higher than that of the winding roll.

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