JP2008307500A - Coating film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a coating film without the need of cleaning the nozzle surface and without contaminating the periphery with the mist of a coating liquid even if the gap between an ink-jet head and a support is lengthened longer than the gap between the same at the time of coating when the joint of the support passes the injection position upon coating by the ink-jet coating method. <P>SOLUTION: When the joint passes the injection position of the ink-jet head after the initiation of coating, the gap between the ink-jet head and the support is provided longer than the same upon coating, so that ink-jet head-leaning injection of the droplets is continued. Moreover, the droplets are recovered by a coating liquid scattering prevention mechanism without coating the support with the droplets. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a coating film forming method in which a coating liquid is applied to the surface of a continuously moving support using an inkjet head that ejects droplets of the coating liquid from a nozzle.

  Conventionally, there are various coating methods in a coating process in which a coating solution is coated on the surface of a support, which is an object to be coated, and the coating methods are roughly divided into two. One is a pre-weighing type coating method in which the coating solution is discharged by an amount that forms the required coating solution film, and the coating solution is applied to the surface of the support. Representative examples include an extrusion coating method, a slide coating method, A curtain coating method may be used. The other is a pre-measurement type coating method in which an excess coating solution is discharged in advance than the necessary coating solution film formation amount, and then the excess coating solution is scraped off by some means, and a typical roll coating method, Examples include an air knife coating method and a wire bar coating method.

  In general, the pre-metering type coating method has a complicated apparatus configuration, but a highly accurate coating liquid film can be obtained. In the post-metering type coating method, the apparatus structure is simple and the processing speed is high, but the former In comparison, the accuracy of the coating liquid film decreases. Here, the said high precision refers to the uniformity of the thickness of the coating liquid film in the moving direction of the support and the direction orthogonal to the moving direction. Further, when comparing the pre-measuring type coating method and the post-measuring type coating method from the viewpoint of the consumption amount of the coating liquid, the pre-measuring type coating method is naturally less and is advantageous in terms of production efficiency.

  Such a conventional coating method has a problem that it is difficult to obtain a highly accurate and thin coating liquid film. That is, although a relatively thin film can be obtained by the post-metering coating method, the accuracy of the coating liquid film is poor as described above. On the other hand, in the pre-metering coating method, the accuracy of the coating liquid film is relatively good, but it is difficult to obtain a thin film.

  On the other hand, the need for a thinner and more accurate coating liquid film for the coatings formed by forming a functional coating liquid film on the support is greatly increased compared to conventional photographic materials. ing. Under such circumstances, research is underway to find out the ink-jet printer technology used in consumer printing equipment and the like, whose demand has been increasing in recent years, for the formation of high-precision thin films of coating liquids. For example, a coating liquid is ejected as droplets from a nozzle by deformation of a flexible plate by a piezoelectric vibrator from an inkjet head (hereinafter also abbreviated as a head) to form a coating liquid film on a support and coating at a constant coverage. It is known to form a pattern in which a liquid film is arranged.

  Here, the coating object refers to a support on which a coating liquid film is formed, and the coating object refers to a coating liquid film formed on the support.

  Formation of a coating liquid film using an inkjet head has been studied for application to various product processing methods. For example, it is a liquid crystal, a photoresist film, an overcoat film, an alignment film, a color filter, various films such as an organic EL material, etc. necessary for manufacturing an electro-optical panel (a liquid crystal display device or an organic EL panel). Moreover, it is being applied not only to these but widely industrial use.

  A number of inventions have been made so far for a method of obtaining a coating liquid film using this inkjet head (hereinafter also referred to as an inkjet coating method). For example, a plurality of inkjet heads are arranged side by side in a direction orthogonal to the moving direction of the support, and a coating liquid film is obtained by ejecting droplets ejected from the nozzle onto the support at a frequency corresponding to the moving speed of the support. The method is representative (see, for example, Patent Document 1). In the ink jet coating method, the amount of droplets and the arrangement pitch on the support can be arbitrarily determined. Therefore, the above-described classification of coating methods is a pre-metering coating method.

  In the ink jet coating method, there is a problem because a small volume of liquid droplets is ejected. As the above problem, there is an injection failure estimated to be caused by drying of the coating liquid at the nozzle port by stopping the injection. An ejection failure is a variation in droplet amount or variation in ejection angle, and the most prominent phenomenon is non-ejection. In order to eliminate this phenomenon, it is necessary to extrude the coating liquid from the nozzle by a different physical force, instead of ejecting the liquid droplet by the deformation of the flexible plate by the piezoelectric vibrator described above. For example, forced liquid feeding using a pump or suction from a nozzle.

  When forced liquid feeding or suction from such a nozzle is performed, the nozzle surface is once wetted with the coating liquid, so if the coating liquid adhering to the nozzle surface is not removed, the flexible plate of the piezoelectric vibrator is used. Droplet ejection due to deformation is not possible. This is because the nozzle is blocked even when the coating liquid is not dried. In order to eliminate this phenomenon, it is necessary to remove the coating liquid on the nozzle surface, so-called cleaning.

  By the way, in the said inkjet coating method, an inkjet head and a support body maintain and maintain a predetermined gap | interval. Further, in order to improve productivity, a long support is used for the support and is often continuously applied. However, the long support may be formed into a long shape by connecting several supports having a certain length due to manufacturing reasons (see FIG. 1). The joints of the joints are bonded together with an adhesive tape (FIG. 1; 10c) such as a splice tape, for example, with the end portions of the respective supports being abutted or overlapped. For this reason, the joint is thicker than the thickness of the support, and the thickness is not constant and varies. Therefore, it is difficult to pass the joint through the ejection portion (nozzle surface) of the inkjet head in the gap. For this reason, the gap between the inkjet head and the support needs to be wider than the predetermined gap. When the gap is thus widened, the surroundings are contaminated by the coating liquid mist.

  In order to prevent the contamination, there is a method of stopping the injection of the coating liquid and preventing the generation of the coating liquid mist. However, when the injection is stopped, it is necessary to remove the coating liquid on the nozzle surface as described above, so-called cleaning. Regarding the cleaning, a method is disclosed in which a wiping sheet impregnated with a cleaning liquid is pressed against a nozzle surface and the sheet is fed (see, for example, Patent Document 2).

Moreover, the method of collect | recovering coating liquid mist with an airflow is disclosed (for example, refer patent document 3).
JP 2004-313895 A JP 2005-111808 A JP 2004-330446 A

  In Patent Document 2, the nozzle surface can be in a clean state, and normal injection can be performed. However, this operation is indispensable every time the injection is stopped, and performing this series of operations when the support joints pass is because the support is moved continuously, so that the loss part of the support It leads to increase.

  In Patent Document 3, the coating liquid mist can be collected without affecting the application in the normal application state. However, if the ink jet head and the support are not maintained at a predetermined gap, the airflow will not move as expected, so there is no adhesion to the nozzle surface when it is necessary to widen the gap as when passing through a joint. It was difficult to recover the coating liquid mist.

  As described above, conventionally, it has been difficult to separate the ink jet head from the support and pass the joint without stopping the injection.

  The present invention has been made in view of the above situation, and even when the gap between the inkjet head and the support is wider than the gap at the time of application when passing through the injection position of the joint of the support in the application by the inkjet application method, It is an object of the present invention to provide a method for forming a coating film that does not require cleaning of the nozzle surface and does not contaminate the surroundings with a coating liquid mist.

The above object is achieved by the following method.
1. Using an inkjet head that ejects droplets of coating liquid from a nozzle, the droplets are ejected from the inkjet head to a continuous support that moves continuously, and the coating liquid is applied. A coating film forming method for forming a liquid film,
When the joint passes through the ejection position of the inkjet head after the start of application, the ejection of the droplets from the inkjet head is continued.
2. 2. The coating film forming method according to 1, wherein when the joint passes through an ejection position of the inkjet head, the droplets ejected from the inkjet head are not applied to the support.
3. Using a coating liquid scattering prevention mechanism that collects the droplets and prevents the coating liquid from scattering, and when the joint passes through the ejection position of the inkjet head, the droplets are not applied to the support. 3. The method of forming a coating film according to 1 or 2, wherein droplets splashing around are collected or the droplets not applied to the support are collected to prevent splashing.

  By the above, when performing application by injecting the coating liquid from the inkjet head, without stopping the injection even when the joint of the support passes the injection position, and without contaminating the surroundings with the coating liquid mist, Application can be continued. Since application can be performed without stopping injection, it is possible to prevent injection failure that is presumed to be caused by drying of the application liquid at the nozzle opening of the inkjet head, and the support on which the application liquid film is formed. The production yield of the body can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1 is a schematic view showing an example of a coating apparatus to which the coating liquid film forming method of the present invention can be applied. FIG. 2 is a partial side view of the vicinity of the coating unit 20 as seen from the direction of the arrow A1 in FIG.

  The long support body 10 wound in a roll shape is fed out in the direction of arrow B from the unwinding roll 10a by a driving means (not shown) and conveyed.

  The long support 10 is conveyed while being supported by the back roll 12, the coating liquid is ejected from the inkjet head 201 of the coating unit 20, and the coating liquid is applied to the support 10 to form a coating liquid film 10 </ b> A. . The support 10 coated with the coating liquid is wound around a winding roll 10b via a drying unit (not shown).

  In the present embodiment, a plurality of inkjet heads 201 are arranged at positions facing the back roll 12 with the support 10 interposed therebetween, corresponding to the coating width in the support width direction. The coating liquid is ejected from the nozzles of the inkjet head 201 in the direction of the rotation center of the back roll 12.

  The arrangement of the inkjet head 201 is not limited to the position shown in FIG. 1, and may be a position that faces the back roll 12 with the support 10 interposed therebetween. Moreover, the inkjet head 201 can also be arrange | positioned in the position which does not oppose the back roll 12, for example, the position in which the support body 10 after passing the back roll 12 is conveyed linearly in a conveyance direction. In this case, in order to stably maintain the gap between the support 10 and the inkjet head 201, a support member that supports the support 10 is provided in the vicinity of the inkjet head 201 on the side opposite to the coating surface of the support 10. Is preferred.

  The coating unit 20 includes a plurality of inkjet heads 201 arranged in the width direction of the support 10, a coating liquid supply mechanism (not shown) for supplying a coating liquid, and a coating liquid tank 22. The coating liquid supply mechanism supplies the coating liquid to the inkjet head 201 and keeps the coating liquid pressure in the inkjet head 201 constant. In addition, the coating liquid is preferably passed through a filter medium having an absolute filtration accuracy or semi-absolute filtration accuracy of 0.01 to 50 μm at least once before being supplied to the inkjet head 201.

  The coating unit 20 is held at a predetermined position by the holding mechanism 30. In the present embodiment, as shown in FIGS. 1 and 2, the application unit 20 can be moved to the application position A and the standby position C above the application position A by holding mechanism moving means (not shown). The holding and movement of the coating unit 20 is not limited to the present embodiment.

  The coating liquid scattering prevention mechanism 50 includes a sheet-like absorbing member 501 that can absorb the coating liquid ejected from the inkjet head 201. For the absorbent member 501, for example, a nonwoven fabric or the like can be used. The absorbing member 501 wound in a roll shape is conveyed in the direction of arrow C from the unwinding unit 502 by an absorbing member conveying mechanism (not shown), and is taken up by the winding unit 503. The conveyance direction of the absorbing member 501 may be opposite to the arrow C. The length in the width direction of the support 10 of the absorbing member 501 is a length corresponding to the nozzle surface length in the ejection width direction of the plurality of inkjet heads 201 arranged.

  The coating liquid scattering prevention mechanism 50 is held at the standby position B when in a standby state such as during application and when the coating apparatus is stopped. The coating liquid scattering prevention mechanism moving means (not shown) moves the coating position A and the standby position. Moved to C. At the standby position B, the conveyance of the absorbing member 501 is stopped. When moving to the application position A, the absorbing member 501 can be inserted between the nozzle surface of the inkjet head 201 and the support 10 as shown in FIGS. 1 and 2. Further, when moving to the standby position C, it is possible to move in synchronization with the coating unit 20 so as to maintain a constant gap between the nozzle surface of the inkjet head 201 and the support 10.

  An arbitrary number and arrangement of inkjet heads 201 are installed in the coating unit 20. The number and arrangement are appropriately set according to the coating liquid to be used and the coating conditions, such as the ejection width of the inkjet head 201 and the coating width of the support 10.

  The inkjet head 201 is not particularly limited. For example, a thermal type head having a heating element and discharging the coating liquid from the nozzle by a rapid volume change due to film boiling of the coating liquid by the heat energy from the heating element may be used. A shear mode type (piezo type) head that has a vibration plate including a piezoelectric element in the ink pressure chamber and discharges the coating liquid by a pressure change of the ink pressure chamber by the vibration plate may be used.

  FIG. 3 shows an example of the inkjet head 201. FIG. 3 is a schematic perspective view showing an example of a head having a partially broken surface, and shows a case of a shear mode type (piezo type) ink jet head. A control unit (not shown) for driving the piezoelectric substrate is connected to the inkjet head 201 via a connector (not shown). The control unit selects the operation strength and frequency of the piezoelectric substrate when the coating liquid is ejected.

  The inkjet head 201 has a piezoelectric substrate 201b formed by joining an upper piezoelectric substrate 201b1 and a lower piezoelectric substrate 201b2, a top plate 201c, and a nozzle plate 201d.

  A plurality of nozzles 201b3 having a predetermined length parallel to each other are opened on the piezoelectric base plate 201b by opening the nozzle plate 201d and closed on the opposite side, and a flat surface connected to the closed side of the nozzle 201b3. A flat surface 201b4 and side walls 201b5 on both sides of a nozzle (ink pressure chamber) 201b3. The plurality of nozzles may be alternately used as a nozzle for a coating solution pressure chamber and a nozzle for an air pressure chamber. FIG. 3 shows a case where it is used for a coating solution pressure chamber. 201c2 shows the 1st top plate which covers the upper surface of the piezoelectric base | substrate 201b, 201c1 shows the 2nd top plate which covers the upper surface of a 1st top plate.

  Reference numeral 201e denotes a coating liquid supply pipe for the coating liquid. The coating liquid supplied from the coating liquid supply pipe 201e is discharged from the nozzle discharge port 201d1. Reference numeral 201c3 denotes a reservoir for the coating liquid supplied from the coating liquid supply pipe 201e, which is supplied to the nozzle 201b3 for each coating liquid pressure chamber from each coating liquid supply port 201c4 communicating with each nozzle 201b3. . Each nozzle 201b3 is covered with a first top plate 201c2 and a nozzle plate 201d, so that a plurality of sealed channels (coating liquid pressure chambers) are formed.

  Reference numeral 201d1 denotes a nozzle discharge port that discharges the coating liquid in the form of droplets due to a change in the pressure of the coating liquid pressure chamber accompanying shear deformation of each side wall. The interval between the nozzle discharge ports is preferably 0.02 to 0.3 mm. Reference numeral 201f denotes a pipe used for bleeding the coating liquid. 201f has a structure sealed by a valve or the like when the coating liquid is injected.

  The material of the first top plate and the second top plate is not particularly limited, and may be made of, for example, an organic material. However, alumina, aluminum nitride, zirconia, silicon, silicon nitride, silicon carbide, quartz, lead zirconate titanate ( PZT) and the like.

  A metal or resin is used as a base material constituting the nozzle plate 201d. For example, stainless steel, polyimide, polysulfone, polyethersulfone and the like can be preferably used. Particularly preferred is a polyimide resin, and DuPont: Kapton or Ube Industries, Ltd .: Upilex, etc. are preferred because they are excellent in dimensional stability, ink resistance, heat resistance and the like.

  Here, the arrangement and arrangement of the inkjet 201 will be described. FIG. 4 is a schematic plan view showing an arrangement angle of the head with respect to the support 10. θ indicates that the coating liquid film surface of the support 10 and the surface 201a of the nozzle plate 201d on which the nozzle discharge port 201d1 of the head 201 is disposed are parallel to each other with a certain distance therebetween, and the head 201 is disposed on the support 10. In this case, the angle formed by the line connecting the centers of the nozzle discharge port 201a row and the moving direction of the support 10 (the direction of the arrow in the figure) is shown. The angle θ is preferably 45 ° to 135 ° in consideration of the size of the head with respect to the width of the support 10, the number of heads to be disposed, and the stability of the coating surface. The broken lines in FIG. 4 indicate the case where θ1 is 45 ° and θ2 is 135 °.

  5 and 6 are schematic plan views showing an example of the installation arrangement of the inkjet heads 201. FIG.

  In FIG. 5, reference numerals 201-1 to 201-5 denote arranged ink jet heads. In the heads 201-1 to 201-5, the surfaces of the heads 201-1 to 201-5 having the nozzle discharge ports and the coating liquid film surface of the support 10 are parallel to each other and maintain a constant interval. The angle formed by the line connecting the centers of the nozzle discharge ports arranged in the width direction orthogonal to the direction and the moving direction of the support 10 is 90 °. Moreover, in order to eliminate an uncoated part between adjacent heads, the ends of the heads 201-1 to 201-5 are arranged in a staggered manner so as to overlap each other. By using a plurality of heads and arranging them as shown in this figure, it becomes easy to cope with the width of the support 10, and there is no uncoated portion between the heads, and a stable coating liquid film is obtained. It is done.

  In FIG. 6, reference numerals 201-a to 201-h denote arranged heads. In the heads 201-a to 201-g, the surfaces of the heads 201-a to 201-h having the nozzle discharge ports and the coating liquid film surface of the support 10 are parallel to each other and maintain a constant interval. The angle formed by the line connecting the centers of the nozzle outlets arranged in the width direction, which is orthogonal to the direction, and the conveying direction of the coated object is 45 °. Further, in order to eliminate an uncoated portion between adjacent heads, the rear end portions and the front end portions of the heads 201-a to 201-h are arranged so as to overlap each other. By using a plurality of heads as described above and arranging them as shown in FIG. 6, it is easy to cope with the width of the support 10 and the interval between the droplets applied from the nozzle discharge ports of each head is narrow. As a result, the coating density in the width direction can be increased, and coating with a stable film thickness can be achieved.

  The arrangement of the heads shown in FIGS. 5 and 6 can be appropriately selected as necessary.

  When coating is performed on the back roll 12 as in the present embodiment, the support 10 at the coating position draws an arc in the transport direction, so that θ in FIG. 4 is 90 ° from the stability and uniformity of coating. The staggered arrangement shown in FIG.

  The support 10 according to the present invention is not limited in type, and paper, plastic film, metal sheet, or the like can be used. Examples of the paper include resin-coated paper and synthetic paper. Examples of plastic films include polyolefin films (eg, polyethylene film, polypropylene film), polyester films (eg, polyethylene terephthalate film, polyethylene 2,6-naphthalate film), polyamide films (eg, polyetherketone film). And cellulose acetate film (for example, cellulose triacetate film). As a metal sheet, an aluminum plate is typical. Moreover, there is no restriction | limiting in particular also about the thickness and the width | variety of the support body 10 to be used.

  The coating liquid according to the present invention preferably contains 0.5 to 20% by mass of a polymer component. Examples of the polymer component include gelatin, methyl cellulose, carboxymethyl cellulose, polyacrylic acid, polyvinyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, and natural rubber. The coating solution containing these polymer components is not particularly limited. For example, coating solutions for general and industrial silver halide photosensitive materials, coating materials for heat-sensitive materials, coating solutions for photothermographic materials, or polymer materials. Examples thereof include a solution obtained by dissolving the azobenzene in an organic solvent, water and the like, a pigment dispersion, a colloidal dispersion, and the like.

The method of the present invention is more suitable for the following coating conditions.
1. The gap between the surface of the nozzle of the inkjet head disposed in the coating object and the coating object is 40 μm to 2000 μm.
2. 2. The wet coating thickness is 40 μm or less Next, the injection of the coating liquid and the coating liquid scattering prevention mechanism 50 will be described with reference to FIGS. 1 and 2.

  First, in the procedure for filling the inkjet head 201 with the coating solution, the coating solution is forcibly fed to the inkjet head 201 moved to the standby position C by a feeding pump (not shown) that feeds the coating solution. . At this time, the coating liquid scattering prevention mechanism 50 is also moved to the standby position C, and the absorbing member 501 is in the state of being conveyed in the direction of arrow C close to the nozzle surface of the inkjet head 201. The gap between the nozzle surface of the inkjet head 201 and the absorbing member 501 is set to about 50 to 1000 μm, and the conveying speed of the absorbing member 501 is set to a speed at which the absorbing member 501 can be absorbed from the amount of coating liquid fed.

  By this operation, the inkjet head 201 is filled with the coating liquid, and after the air is removed, the nozzle surface of the inkjet head 201 is cleaned. In this case, the coating liquid scattering prevention mechanism 50 is further moved toward the ink jet head 201 to bring the absorbing member 501 into contact with the nozzle surface. At this time, the absorbing member 501 may be in a conveying state or a stopped state. Further, the absorbing member 501 may be brought into contact with the nozzle surface in a stopped state and then conveyed.

  After the cleaning, the gap between the nozzle surface and the absorbing member 501 is returned to the gap set above (about 50 to 1000 μm), the inkjet head is driven at a frequency corresponding to the coating conditions, and the coating droplets are ejected. Perform injection inspection. Also in the case of performing injection, the absorbing member 501 is transported at a speed capable of absorbing the coating liquid as in the case of forced feeding of the coating liquid. If the result of the injection inspection is good, the process proceeds to the coating operation. If the result of the injection inspection is poor, the operation is restarted from forced application liquid feeding or cleaning of the nozzle surface.

  If the above-described injection inspection is good, the application unit 20 and the application liquid scattering prevention mechanism 50 move to the application position A while keeping the gap between the nozzle surface and the absorbing member 501 without stopping the injection operation. Next, the coating liquid scattering prevention mechanism 50 is retracted to the standby position B while the support 10 is being transported at a predetermined speed, and application to the support 10 is started.

  On the other hand, when the joint of the support 10 passes through the nozzle surface (ejecting portion) of the inkjet head 201 during coating, the coating unit 20 is temporarily placed at the coating position A in order to avoid contact between the joint and the nozzle surface. To the standby position C. When the joint approaches the nozzle surface, first, the coating liquid scattering prevention mechanism 50 moves from the standby position B to the coating position A, while transporting the absorbing member 501 to the gap between the nozzle surface of the inkjet head 201 and the support 10. insert. Next, the coating unit 20 and the coating liquid scattering prevention mechanism 50 move toward the standby position C while maintaining a gap between the nozzle surface and the absorbing member 501. With the absorbing member 501 and the support member 10 sufficiently separated, the joint of the support 10 passes.

  After passing through the joint, the coating unit 20 and the coating liquid scattering prevention mechanism 50 start moving toward the coating position A while maintaining the gap between the nozzle surface and the absorbing member 501 again. The liquid splash prevention mechanism 50 is retracted to the standby position B. During this time, the conveyance of the absorbing member is not stopped, and the retracting of the coating liquid scattering preventing mechanism is completed, and the conveying of the absorbing member is stopped.

  In the operation at the time of passing through the joint, the ejection of droplets from the ink jet head 201 is continuously performed without being stopped. The ejected droplets that are not applied to the support 10 are absorbed by the absorbing member 501.

  As described above, when the joint of the support 10 passes through the nozzle surface of the inkjet head 201, the ejection of the droplets of the inkjet head 201 can be continued without stopping. Cleaning is unnecessary. Moreover, since the droplet ejected when passing through the joint can be absorbed by the absorbing member 501 of the coating liquid scattering prevention mechanism 50 without being applied to the support 10, the coating liquid mist is prevented from being scattered around. And can prevent the surrounding contamination.

  Further, even when the above-described inkjet head 201 is filled with the coating liquid, since the liquid droplets that are not applied to the support 10 can be absorbed by the absorbing member 501, it is possible to prevent the coating liquid mist from being scattered around. And the surrounding contamination can be prevented.

Next, another embodiment of the coating liquid scattering prevention mechanism will be described.
[Another form 1]
FIG. 7 is a diagram showing another embodiment 1 of the coating liquid scattering prevention mechanism. In another form 1, the coating liquid scattering prevention mechanism 60 is arranged on the upstream side or the downstream side in the transport direction of the support 10 in the vicinity of the nozzle surface of the inkjet head 201, or both, and the ejected droplets are sucked. The coating liquid scattering prevention mechanism 60 includes a suction part 61 having an opening 61a, a suction pump P, and a suction pipe 62, and is not applied to the support 10 from the opening 61a of the suction part 61 by the suction pump P. The scattered droplets are sucked and collected in a drainage tank (not shown). The suction unit 61 has a length in the width direction of the support 10 corresponding to the ejection width of the plurality of inkjet heads 201 arranged.

  The suction unit 61 can move in synchronization with the inkjet head 201 to the application position A and the standby position C while maintaining the positional relationship with the inkjet head 201. When the inkjet head 201 is filled with the coating liquid, when the joint passes, and when the coating apparatus is stopped, the ink jet head 201 moves to the standby position C.

The coating liquid splash prevention mechanism 60 is for sucking and collecting the liquid droplets that are not applied to the support 10 while the coating liquid splash prevention mechanism 50 absorbs the liquid droplets to the absorbing member 501 and collects them. . The function conforms to the function of the coating liquid scattering prevention mechanism 50 described above, but movement to the standby position B is not necessary.
[Another form 2]
8 and 9 are diagrams showing another embodiment 2 of the coating liquid scattering prevention mechanism. FIG. 8 shows a state at the time of application, FIG. 8 (a) is a side view, and FIG. 8 (b) is a front view seen from the direction of arrow A8. FIG. 9 shows a state when not applied.

  The coating liquid scattering prevention mechanism 70 of another embodiment 2 collects the liquid droplets that are not applied to the support 10 by absorbing the liquid droplets that are not applied to the support 10 in the same manner as the coating liquid scattering prevention mechanism 50 described above. Further, the coating liquid scattering prevention mechanism 50 transports the absorbing member 501 in the moving direction of the support 10, whereas the coating liquid scattering preventing mechanism 70 transports the absorbing member 701 in the width direction of the supporting body 10.

  The coating liquid scattering prevention mechanism 70 includes a sheet-like absorbing member 701 that can absorb the coating liquid ejected from the inkjet head 201. For the absorbent member 701, for example, a nonwoven fabric or the like can be used. The absorbing member 701 wound in a roll shape is conveyed in the direction of arrow D from the unwinding unit 702 by an absorbing member conveying mechanism (not shown), and is taken up by the winding unit 703. The conveyance direction of the absorbing member 701 may be opposite to the arrow D. The unwinding part 702 and the winding part 703 are disposed across the support 10 and the back roll 12 as shown in FIG. Moreover, it can also arrange | position upwards so that the coating unit 20 may be straddled.

  The coating liquid scattering prevention mechanism 70 moves to a coating position A shown in FIG. 8 at the time of coating, and synchronizes with the back roll 12 when the inkjet head 201 is filled with the coating liquid, when the joint passes, and when the coating device is stopped. That is, it synchronizes with the support body 10, moves in the direction of arrow E, and moves to the standby position D shown in FIG. At this time, the position of the coating unit 20 is fixed and does not move. On the contrary, the position of the coating liquid scattering prevention mechanism 70 and the back roll 12 may be fixed and the coating unit 20 may be moved.

Further, the function conforms to the function of the coating liquid scattering prevention mechanism 50 described above. Compared with the coating liquid scattering prevention mechanism 50, the width of the absorbing member 701 can be reduced.
[Another form 3]
FIG. 10 is a diagram showing another embodiment 3 of the coating liquid scattering prevention mechanism. The coating liquid scattering prevention mechanism 80 according to another embodiment 3 includes a receiving pan 801, a cleaning liquid tank 802, and a recovery tank 803. The cleaning liquid tank 802 stores the main solvent of the coating liquid or a highly cleaning solvent as a cleaning liquid and flows down to the receiving pan 801. Droplets that are not applied to the support 10 are received by a receiving pan 801 in which the cleaning liquid is flowing down and collected in a collection tank 803.

  The coating liquid scattering prevention mechanism 80 moves to the same position as the coating liquid scattering prevention mechanism 50 shown in FIGS. That is, the coating liquid scattering prevention mechanism 80 is held at the standby position B in FIG. 1 during coating and when the coating apparatus is in a stopped state, and the coating liquid scattering prevention mechanism moving means (not shown) 1 and the application position A and the standby position C in FIG. At the standby position B, the flow of the cleaning liquid stops, and at the application position A and the standby position C, the cleaning liquid flows down.

  When moving to the application position A, a receiving pan 801 can be inserted between the nozzle surface of the inkjet head 201 and the support 10 as shown in FIG. Further, when moving to the standby position C, it can be moved in synchronization with the coating unit 20 so as to maintain a constant gap between the nozzle surface of the ink jet head 201 and the receiving pan 801.

The coating liquid scattering prevention mechanism 80 receives and drops by the receiving pan 801 while the above-described coating liquid scattering prevention mechanism 50 absorbs the liquid droplets that are not applied to the support 10 by the absorbing member 501 and collects them. It collects in the collection tank 803 together with the cleaning liquid. The function conforms to the function of the coating liquid scattering prevention mechanism 50 described above.
<Example>
Using the coating apparatus and coating liquid scattering prevention mechanism 50 shown in FIGS. 1 and 2, coating was performed and evaluated.
(Preparation of coated material)
A polyethylene terephthalate film having a thickness of 75 μm, a width of 600 mm, and a length of 1000 m was prepared as the support 10.
(Preparation of coating solution)
Polyvinyl alcohol was dissolved in a 70:30 mass ratio solvent of pure water and methanol to prepare a coating solution having a viscosity of 5.0 mPa · s. The viscosity is a value measured using a B-type viscometer at a temperature of 25 ° C.
(Application)
The prepared support 10 and the prepared coating solution were applied using the coating apparatus shown in FIGS. 1 and 2 while changing the treatment when the support 10 was passed through the joint as shown in Table 1. The coating length was set to 10,000 m of 1000 m × 10 windings.

  The application conditions at the time of application were as follows.

The droplet velocity when the droplet ejected from the nozzle discharge port of the ink jet head landed on the coated body was set to 6.5 m / s. The conveyance speed of the polyethylene terephthalate film which is a coating object was 25 m / min. The inkjet head 201 uses the shear mode type (piezo type) shown in FIG. 3, the nozzle discharge port diameter is 0.04 mm, the average discharge amount per droplet of coating liquid is 50 pl, the pitch between nozzles is 0.07 mm, and the number of nozzles 500 ones were used. A plurality of ink jet heads were arranged so as to obtain a coating liquid film having a width of 550 mm in a zigzag pattern shown in FIG. The liquid temperature of the coating liquid was 25 ° C. The injection conditions were set to 4 μm when the injected coating droplets spread with a uniform thickness across the coating liquid film width.
(Absorbing member 501)
A sheet-like polyolefin nonwoven fabric was used in the form of a roll.
(Evaluation of application)
The length which can be used as a product was measured while the above 10,000 m was applied. Judgment as to whether or not it can be used as a product is based on the presence or absence of streaks, and the portion without streaks is regarded as a product. Table 1 shows the application results. In Table 1, the product length is the length of a part that can be used as a product.

  From the above, the effectiveness of the present invention was confirmed.

It is the schematic which shows an example of the coating device which can apply the coating-film formation method of this invention. It is the partial side view of the coating unit vicinity seen from the arrow A1 direction of FIG. It is a figure which shows an example of an inkjet head. It is a schematic plan view which shows the arrangement | positioning angle of the head with respect to a support body. It is a schematic plan view which shows an example of the installation arrangement | sequence of an inkjet head. It is a schematic plan view which shows an example of the installation arrangement | sequence of an inkjet head. It is a figure which shows another form of a coating liquid scattering prevention mechanism. It is a figure which shows another form of a coating liquid scattering prevention mechanism. It is a figure which shows the state at the time of the non-application | coating of the coating liquid scattering prevention mechanism shown in FIG. It is a figure which shows another form of a coating liquid scattering prevention mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Support body 10a Winding roll 10b Winding roll 12 Back roll 20 Application | coating unit 201 Inkjet head 22 Coating liquid tank 30 Holding mechanism 50, 60, 70, 80 Coating liquid scattering prevention mechanism 501, 701 Absorbing member 502, 702 Unwinding part 503, 703 Winding part 61 Suction part 62 Suction pipe 801 Receiving pan 802 Cleaning liquid tank 803 Recovery tank P Pump

Claims (3)

Using an inkjet head that ejects droplets of coating liquid from a nozzle, the droplets are ejected from the inkjet head to a continuous support that moves continuously, and the coating liquid is applied. A coating film forming method for forming a liquid film,
When the joint passes through the ejection position of the inkjet head after the start of application, the ejection of the droplets from the inkjet head is continued. The coating film forming method according to claim 1, wherein when the joint passes through an ejection position of the inkjet head, the droplet ejected from the inkjet head is not applied to the support. Using a coating liquid scattering prevention mechanism that collects the droplets and prevents the coating liquid from scattering, and when the joint passes through the ejection position of the inkjet head, the droplets are not applied to the support. The method for forming a coating film according to claim 1, wherein droplets scattered around are collected or the droplets not applied to the support are collected to prevent scattering.

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