JP2022144386A - Inkjet coating device - Google Patents

Abstract

To provide an inkjet coating device which can inhibit nozzle clogging from being caused by a coating liquid in a liquid sending pipe which supplies the coating liquid to an inkjet head.SOLUTION: An inkjet coating device includes: a coating liquid tank in which a coating liquid is stored; and an inkjet head which is connected to the coating liquid tank through a liquid sending pipe and discharges the coating liquid in a droplet form. The liquid sending pipe is provided with an in-line cleaning part which cleans the interior of the liquid sending pipe. The in-line cleaning part achieves a cleaning function through the coating liquid in the liquid sending pipe or a cleaning liquid.SELECTED DRAWING: Figure 3

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet coating apparatus that ejects droplet-like coating liquid, and more particularly to an inkjet coating apparatus having a cleaning mechanism.

2. Description of the Related Art Coating films (film patterns) having various shapes such as lines and rectangles are formed on substrates such as glass and films by an inkjet coating device. As shown in FIG. 9A, the inkjet coating apparatus includes a stage 100 on which a substrate W is placed, and an inkjet head 101 having a head module 102 for ejecting a coating liquid (droplet). A highly accurate film pattern is formed by ejecting droplets from the nozzle holes 104 of the head module 102 onto a predetermined position on the substrate W while moving the W and the inkjet head 101 relative to each other.

As the inkjet coating device is operated, the coating liquid adheres to the nozzle surface 103 on which the nozzle holes 104 (see FIG. 9B) are formed, which causes ejection failure, flight deflection, etc., and decreases the landing accuracy. do. Therefore, the inkjet coating apparatus includes a cleaning device 110, and cleaning the inkjet head 101 periodically allows the coating liquid to land with high accuracy. That is, the cleaning device 110 has a cleaning section 110a that cleans the nozzle surface 103 with a cleaning liquid, a wiping section 110b that wipes the cleaned nozzle surface 103, and a tray section 110c that ejects droplets. By cleaning 103 by cleaning device 101, the ejection state of each nozzle hole 104 is recovered. Then, in the tray portion 110c, bleeding and flushing are performed by forcibly ejecting the coating liquid from the nozzle holes 104, and the nozzle surface 103 is wiped off again, so that the ejection state of the nozzle holes 104 is restored to normal. It is recovered (see, for example, Patent Document 1 below).

JP 2012-201076 A

However, the ink jet device described above has a problem that nozzle clogging may not be completely eliminated. That is, the supply of the coating liquid to the inkjet head 101 is performed from the coating liquid tank through the liquid feeding pipe, and the coating liquid may gel or solidify in the liquid feeding pipe. Once the gelled and solidified coating liquid peels off from the liquid feeding pipe, it may be fed together with the coating liquid in the liquid feeding pipe and enter the nozzle hole to cause nozzle clogging.

The present invention has been made in view of the above problems, and is an inkjet coating that can suppress the occurrence of nozzle clogging caused by the coating liquid in the liquid feeding pipe that supplies the coating liquid to the inkjet head. The purpose is to provide a device.

In order to solve the above problems, the inkjet coating apparatus of the present invention includes a coating liquid tank in which a coating liquid is stored, and an inkjet head connected to the coating liquid tank by a liquid feeding pipe and ejecting a droplet-shaped coating liquid. , wherein the liquid-sending pipe is provided with an in-line cleaning unit for cleaning the inside of the liquid-sending pipe.

According to the inkjet coating apparatus, since the liquid-sending pipe is provided with the in-line cleaning unit, the inside of the liquid-sending pipe can be cleaned by the in-line cleaning unit. That is, even if the coating liquid gels and solidifies in the liquid feed pipe, the inside of the liquid feed pipe is washed by the in-line washing unit, and the gelled and solidified coating liquid peels off, causing nozzle clogging. can be suppressed.

Further, the in-line cleaning unit is formed by a cleaning pipe connected to the liquid sending pipe to which the cleaning liquid is sent, and a cleaning function unit that exerts a cleaning function, and the cleaning function unit performs the cleaning function through the cleaning solution. It is good also as a structure demonstrated.

According to this configuration, the cleaning function of the cleaning function unit can be exerted on the liquid feeding pipe via the cleaning liquid supplied from the cleaning liquid pipe to the liquid feeding pipe, so that only the cleaning liquid is fed to the liquid feeding pipe. The gelled and solidified coating liquid can be effectively removed as compared with the case where the cleaning is carried out with a liquid.

The in-line cleaning unit is formed of a cleaning function unit that exerts a cleaning function. The cleaning function unit is provided in the liquid feeding pipe, and the cleaning function is performed via the coating liquid in the liquid feeding pipe. You may make the structure demonstrated.

According to this configuration, since the cleaning function can be exerted through the coating liquid in the liquid-feeding pipe, it is necessary to dry the inside of the liquid-feeding pipe after washing without changing the liquid environment in the liquid-feeding pipe. Therefore, the cleaning process by the cleaning function unit can be performed at a predetermined timing.

Moreover, as a specific mode of the cleaning function part, an ultrasonic vibrator or a microbubble generator can be used.

According to the inkjet coating apparatus of the present invention, it is possible to suppress the occurrence of nozzle clogging caused by the coating liquid in the liquid feeding pipe that supplies the coating liquid to the inkjet head.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view which shows roughly the inkjet coating device in one Embodiment of this invention. It is a top view which shows the said inkjet coating device roughly. 4 is a piping route diagram around the inkjet head; FIG. It is a figure which shows the said inkjet head, (a) is the figure seen from the nozzle surface side, (b) is an enlarged view of a head module. It is the figure which looked at the washing|cleaning part from the Y-axis direction. It is the figure which looked at the washing|cleaning part from the X-axis direction. It is a figure which shows a wiping part. FIG. 10 is a piping route diagram around an inkjet head in another embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the conventional inkjet coating device roughly, (a) is a side view, (b) is a figure which shows an inkjet head.

An embodiment of an inkjet coating apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a side view showing an embodiment of an inkjet coating device equipped with a cleaning device, FIG. 2 is a top view of the inkjet coating device, FIG. 3 is a piping route diagram around the inkjet head, and FIG. , and is a view of the inkjet head viewed from the nozzle surface side. Note that the ink used in the inkjet coating apparatus of the present embodiment may be any ink that can be ejected in an inkjet format, such as ink used for color filters, organic EL, conductive ink for wiring patterns, and protective films. Can be targeted.

As shown in FIGS. 1 to 4, the inkjet coating device 1 has a stage 2 on which the substrate W is placed, and a droplet unit 3 for ejecting ink onto the substrate W. A predetermined pattern is formed on the substrate W by ejecting ink onto a predetermined position while moving over the substrate W placed on the stage 2 .

In the following description, the direction in which the droplet unit 3 moves is the X-axis direction, the direction orthogonal to this on the horizontal plane is the Y-axis direction, and the direction orthogonal to both the X-axis and Y-axis directions is the Z-axis direction. We will proceed with the explanation as follows.

In this embodiment, the droplet unit 3 applies a coating liquid (droplets) onto the substrate W, and includes an inkjet head 31 for ejecting the coating liquid and a gantry 32 for supporting the inkjet head 31. have. The gantry 32 has support members 32a provided at both ends of the stage 2 in the Y-axis direction, and beam portions 32b connecting the two support members 32a. have a shape. A rail 21 extending in the X-axis direction is provided at a position adjacent to the stage 2, and the support members 32a are provided slidably along the rail 21, respectively. The support member 32a is provided with a drive means such as a linear motor, and by driving and controlling the linear motor, the support member 32a can be moved in the X-axis direction and stopped at an arbitrary position. there is That is, the droplet unit 3 can move in the X-axis direction while straddling the stage 2 and stop at an arbitrary position. The rail 21 extends to the cleaning device 4, and the droplet unit 3 can be stopped at the cleaning device 4 by driving and controlling the linear motor.

An ink jet head 31 for ejecting ink is provided in the beam portion 32b. The inkjet head 31 can move up and down with respect to the base material W by moving the beam portion 32b up and down with respect to the support member 32a. As a result, the distance between the substrate W and the inkjet head 31 is adjusted appropriately during the application operation of ejecting the ink onto the substrate W. FIG. Further, the inkjet head 31 is attached so as to be movable in the Y-axis direction along the beam portion 32b. That is, the inkjet head 31, which faces the base material W at a predetermined position in the X-axis direction, moves in the Y-axis direction so that it can face all the Y-axis direction regions of the base material W at the predetermined position in the X-axis direction. It has become. That is, the support member 32a moves along the rail 21 to move in the X-axis direction, and the ink jet head 31 moves in the Y-axis direction along the beam portion 32b, thereby ink jetting onto a predetermined position of the substrate W. The head 31 can be moved and the ink can be landed.

Further, the inkjet head 31 has a plurality of head modules 5 mounted on a substrate facing surface 30a (see FIG. 4A) facing the substrate W, and ink is ejected from the head modules 5 . The head module 5 is an ink ejection device using a piezoelectric element as a drive source. The head module 5 has nozzle holes 51 for ejecting ink, and a plurality of nozzle holes 51 are aligned in the longitudinal direction of the head module 5 on a nozzle surface 51a (see FIG. 4B) facing the substrate W. arranged in the same direction. In the example of FIG. 4, the nozzle holes 51 are arranged in the Y-axis direction.

The head modules 5 have overlapping portions in the Y-axis direction and are arranged adjacent to each other in the X-axis direction. there is That is, the head modules 5 are arranged in the Y-axis direction while being shifted in the X-axis direction so as to offset the dimensions of the nozzle arrangement interval and the both end portions of the head module 5. . By repeatedly arranging the assembly of the three head modules 5 arranged in a stepwise manner in the Y-axis direction so as to offset the dimensions of the both end portions of the head modules 5, the entire inkjet head 31 is arranged in the X-axis direction. 1, all the nozzle holes 51 are arranged along the Y-axis direction, and are arranged at regular intervals along the Y-axis direction when viewed from the X-axis direction.

A plurality of nozzle holes 51 are formed in a nozzle surface 51a of the head module 5, and the positions of the tips of the nozzle holes 51 and the nozzle surface 51a are substantially aligned. That is, the nozzle surface 51a has a flat shape, and the nozzle holes 51 are flush with the nozzle surface 51a. In the inkjet head 31, the nozzle surfaces 51a of all the integrated head modules 5 are arranged in a state facing the substrate W side, and all the nozzle surfaces 51a are parallel to the substrate W. . By driving the piezo element, ink can be ejected one drop at a time from each of the nozzle holes 51 arranged on the nozzle surface 51a.

Further, the coating liquid supplied to the inkjet head 31 is stored in the coating liquid tank 10 (see FIG. 3). The coating liquid tank 10 is for storing the coating liquid to be discharged onto the substrate W, and stores the amount of the coating liquid necessary for production. As shown in FIG. 3, the inkjet head 31 is connected to the coating liquid tank 10 by a liquid feeding pipe 11, and when the coating liquid tank 10 is pressurized, the coating liquid in the coating liquid tank 10 is fed. The liquid is sent to the inkjet head 31 through the liquid pipe 11 . Further, a bubble removing tank 12 is provided in the liquid feeding pipe 11, and the bubble removing tank 12 removes foreign matter including bubbles in the coating liquid.

A cleaning device 4 is arranged at a position adjacent to the stage 2 in the X-axis direction. The cleaning device 4 removes the coating liquid adhering to the nozzle surface 51a of the head module 5 and recovers the ejection state of the nozzle hole 51. The cleaning unit 41 cleans the nozzle surface 51a, and and a wiping portion 71 for wiping the nozzle surface 51a.

As shown in FIGS. 5 and 6, the cleaning section 41 includes a waste liquid tray 41 for receiving the cleaning liquid to be discarded (a mixture of the cleaning liquid and the removed ink), and a cleaning unit 42 for ejecting the cleaning liquid. there is During the cleaning operation, ink is removed by ejecting the cleaning liquid ejected from the cleaning unit 42 onto the nozzle surface 51a while the inkjet head 31 is arranged on the waste liquid tray 41. FIG.

The waste liquid tray 41 has a container shape that is open upward, and can store washing liquid and the like to be discarded. A cleaning unit 42 is provided in the waste liquid tray 41 . The cleaning unit 42 has a cleaning liquid jetting section 43 for jetting the cleaning liquid, and a cleaning frame tray 44 to which the cleaning liquid jetting section 43 is attached. The nozzle surface 51 a can be cleaned by ejecting the cleaning liquid from the portion 43 .

The cleaning frame tray 44 has a cleaning solution spraying part 43 attached to its bottom surface 44a. The cleaning frame tray 44 is formed to have approximately the same size as the inkjet head 31 , and a side wall portion 44 b vertically extending from an end portion located around the bottom portion 44 a extends above the cleaning frame tray 44 to the inkjet head 31 . is arranged, it faces the inkjet head 31 . A sealing portion 46 is annularly provided on a facing surface 44b1 of the side wall portion 44b that faces the substrate facing surface 30a. there is

Further, the cleaning frame tray 44 is provided with an elevating mechanism 49 that moves up and down in the vertical direction. is configured as Therefore, when the cleaning frame tray 44 is lifted by the elevating mechanism 49 in a state where the inkjet head 31 is arranged above the cleaning frame tray 44, the sealing portion 46 provided on the side wall portion 44b is caused to face the substrate of the inkjet head 31. The area formed by the substrate facing surface 30a of the inkjet head 31 and the cleaning frame tray 44 is sealed from the outside. As a result, even if the cleaning liquid is jetted from the cleaning liquid jetting portion 43, it is possible to prevent the cleaning liquid from scattering to the outside.

The cleaning liquid jetting section 43 jets the cleaning liquid directly onto the nozzle surface 51 a of the inkjet head 31 . The cleaning liquid injection part 43 is a shower type nozzle (shower nozzle 47), and two shower nozzles 47 are arranged along one direction in this embodiment. Specifically, two shower nozzles 47 are provided at the central position in the width direction (lateral direction) of the washing frame tray 44, and these two shower nozzles 47 are provided at a plurality of locations in the longitudinal direction at predetermined intervals. (See Figure 6). That is, the shower nozzle 47 is arranged at a position where the cleaning liquid can be ejected along the longitudinal direction of the inkjet head 31 with the inkjet head 31 arranged above the cleaning frame tray 44 .

The shower nozzle 47 is a portion from which the cleaning liquid is jetted, and a large number of injection holes through which the cleaning liquid is jetted are formed in the main body portion. These jetting ports are oriented so as to jet directly toward the nozzle surface 51 a of the inkjet head 31 when the inkjet head 31 is arranged above the cleaning frame tray 44 . In the present embodiment, the shower nozzle 47 is set to spray in a fan shape from the main body portion so as to spray toward the nozzle surfaces 51a of all the head modules 5 arranged on the substrate facing surface 30a. Cleaning fluid is sprayed. As a result, the ink adhering to the nozzle surface 51a is softened by the components of the cleaning liquid, and is peeled off and removed from the nozzle surface 51a by the jetting force of the cleaning liquid.

The wiping part 71 is for wiping off the cleaning liquid remaining on the nozzle surface 51 a after cleaning by the shower nozzle 47 . Specifically, as shown in FIG. 7, a wiping member 73, which is a band-shaped cloth member, is stretched between rolls 72 spaced apart in the Y-axis direction. The wiping member 73 is formed so that it is let out and the other roll 72 winds up the wiping member 73 . During the wiping operation, when the inkjet head 31 with the cleaning liquid adhering to the nozzle surface 51a descends onto the wiping member 73, the nozzle surface 51a is pressed by the wiping member 73, so that the coating liquid, cleaning liquid, etc. adhering to the nozzle surface 51a are wiped off. The nozzle surface 51 a is wiped off by being absorbed by the water absorbing power of the wiping member 73 . Then, the wiping member 73 to which the cleaning liquid is adhered is wound up by the roll 72, and when the wiping member 73 on the draw-out side runs out, the roll 72 around which the new wiping member 73 is wound is supplied. That is, the wiping member 73 that wipes the nozzle surface 51a is always supplied with a new wiping member 73, so that the wiped cleaning liquid can be prevented from adhering to the nozzle surface 51a again. .

A drain tray 8 for dumping the coating liquid is provided at the end in the X-axis direction, and bleeding and flushing operations are performed in this drain tray 8 . That is, the bleeding operation and the flushing operation are performed by ejecting ink to the drainage tray portion 8 while the inkjet head 31 is arranged on the drainage tray portion 8 .

In addition to the cleaning device 4 , the inkjet coating device 1 is provided with an in-line cleaning section 6 . The in-line cleaning unit 6 cleans the inside of the liquid-feeding pipe 11 and removes the remaining coating liquid (also referred to as residual coating liquid) adhered to the inside of the liquid-feeding pipe 11 due to gelation, solidification, or the like. is. As shown in FIG. 3 , the in-line cleaning unit 6 is provided in the liquid-sending pipe 11 via a three-way valve 61 . That is, by switching the three-way valve 61, the state in which the coating liquid tank 10 and the inkjet head 31 are connected and the state in which the inkjet head 31 and the in-line cleaning section 6 are connected are switched.

The inline cleaning section 6 has a cleaning pipe 62 and a cleaning function section 63 . The cleaning pipe 62 is a pipe that connects the liquid feeding pipe 11 and the cleaning liquid tank 64, and is used to supply the cleaning liquid used for in-line cleaning to the liquid feeding pipe 11. As shown in FIG. The cleaning liquid tank 64 stores a cleaning liquid for cleaning the inside of the liquid feeding pipe 11, and the cleaning liquid is supplied by pressurizing the cleaning liquid tank 64 during in-line cleaning.

The cleaning function part 63 exhibits a cleaning function of removing the residual coating liquid, and in this embodiment, an ultrasonic vibrator is used. As a result, the inside of the liquid feeding pipe 11 is ultrasonically cleaned during in-line cleaning. That is, during in-line cleaning, when the ultrasonic vibrator is operated while the cleaning liquid is being supplied from the cleaning pipe 62 to the liquid feeding pipe 11, the ultrasonic vibration is transmitted into the liquid feeding pipe 11 through the cleaning liquid, and the inside of the liquid feeding pipe 11 is is ultrasonically cleaned, including cavitation effects. That is, the residual coating liquid gelled and solidified in the liquid feeding pipe 11 is separated and removed by the ultrasonic vibration. The inkjet head 31 is also connected to a waste liquid tank 65 , and the cleaning liquid used for in-line cleaning is discharged to the waste liquid tank 65 . By performing in-line cleaning in this way, the coating liquid remaining in the liquid feeding pipe 11 is removed, so that the nozzle clogging caused by the coating liquid in the liquid feeding pipe 11 can be suppressed. can. Although the cleaning function part 63 is provided in the cleaning pipe 62 in this embodiment, it may be provided in the cleaning liquid tank 64 to apply ultrasonic vibration from the cleaning liquid tank 64 . In other words, the cleaning function part 63 may perform the cleaning function through the liquid in the liquid feeding pipe 11 .

Since this in-line cleaning process cleans the inside of the liquid feeding pipe 11 compared to the above-described cleaning device 4, it is maintenance work when replacing with a different type of coating liquid or when stopping the inkjet coating device 1 for a long period of time. done at times. As will be described later, by using a coating liquid as the cleaning liquid, the in-line cleaning process can be performed at the same timing as the cleaning device 4 described above.

As described above, according to the inkjet coating apparatus 1 described above, since the in-line cleaning unit 6 is provided in the liquid-sending pipe 11 , the inside of the liquid-sending pipe 11 can be cleaned by the in-line cleaning unit 6 . That is, even if the coating liquid gels and solidifies in the liquid feeding pipe 11, the inside of the liquid feeding pipe 11 is washed by the in-line cleaning unit 6, and the gelled and solidified coating liquid peels off to prevent nozzle clogging. You can prevent it from happening. Since the cleaning function of the cleaning function unit 63 can be exerted on the liquid feeding pipe 11 via the cleaning liquid supplied from the cleaning pipe 62 to the liquid feeding pipe 11, only the cleaning liquid is fed to the liquid feeding pipe 11. The gelled and solidified coating liquid can be effectively removed as compared with the case where the coating liquid is dried and washed.

Further, in the above-described embodiment, an example of using an ultrasonic transducer as the cleaning function unit 63 has been described, but a microbubble generator may be used. Even when this microbubble generator is used, the microbubbles act on the residual coating liquid adhering to the inside of the liquid feeding pipe 11 through the cleaning liquid, and peel off the residual coating liquid. The coating liquid can be removed.

Further, in the above-described embodiment, an example in which the cleaning function part 63 is provided in the cleaning pipe 62 has been described, but the cleaning function part 63 may be provided directly in the liquid sending pipe 11 . That is, as shown in FIG. 8 , for example, an ultrasonic vibrator as the cleaning function unit 63 is directly attached to the liquid feeding pipe 11 . In this case, the liquid-feeding pipe 11 is filled with the coating liquid, and the ultrasonic vibrator acts on it. The remaining coating liquid in the liquid pipe 11 is separated and removed by the ultrasonic vibration.

Further, in the above embodiment, an example in which the cleaning liquid is used for the cleaning liquid tank 64 and the cleaning pipe 62 has been described, but a coating liquid may be used as the cleaning liquid. That is, the cleaning liquid used in the cleaning liquid tank 64 and the cleaning pipe 62 may be a medium on which the cleaning function unit 63 acts, and includes the coating liquid. If the coating liquid is used as the cleaning liquid, in-line cleaning can be performed without changing the liquid environment in the liquid feeding pipe 11. Therefore, the in-line cleaning process by the cleaning function unit 63 can be performed at a predetermined time, such as during product production. can be done in time.

REFERENCE SIGNS LIST 1 inkjet coating device 3 droplet unit 4 cleaning device 6 in-line cleaning unit 10 coating liquid tank 11 liquid feeding pipe 31 inkjet head 51 nozzle hole 51a nozzle surface 62 cleaning pipe 63 cleaning function unit 64 cleaning liquid tank

Claims (5)

a coating liquid tank in which the coating liquid is stored;
an inkjet head that is connected to the coating liquid tank by a liquid feeding pipe and ejects a coating liquid in the form of droplets;
with
An inkjet coating apparatus, wherein the liquid-sending pipe is provided with an in-line cleaning section for cleaning the inside of the liquid-sending pipe. The in-line cleaning unit is formed by a cleaning pipe connected to the liquid sending pipe to which the cleaning liquid is sent, and a cleaning function unit that performs a cleaning function, and the cleaning function unit performs the cleaning function through the cleaning liquid. The inkjet coating device according to claim 1, characterized in that: The in-line cleaning part is formed of a cleaning function part that exerts a cleaning function. This cleaning function part is provided in the liquid feeding pipe, and the cleaning function is exerted through the coating liquid of the liquid feeding pipe. The inkjet coating device according to claim 1 or 2, characterized in that: 4. The inkjet coating apparatus according to claim 2, wherein the cleaning function unit is an ultrasonic oscillator. 4. The inkjet coating apparatus according to claim 2, wherein the cleaning function unit is a microbubble generator.

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