JP2010096816A - Apparatus and method for supplying coating liquid to inkjet head and method for producing color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for supplying a coating liquid to an inkjet head, which is filled with only the coating liquid, wherein even mistakenly mixed air or even air bubbles of dissolved air are discharged to the outside to sweep away obstacles caused by air bubbles in the inkjet head, and the quality of the coating liquid is prevented from being deteriorated owing to the retention so that the quality of the coating liquid can be kept over a long time; and to provide a method for supplying the coating liquid to the inkjet head. <P>SOLUTION: The apparatus 1 for supplying the coating liquid to the inkjet head comprises an intermediate tank 30 which is arranged midway between a coating liquid tank and the inkjet head 100 and is filled with the coating liquid and in which the coating liquid of constant volume can be stored temporarily. The intermediate tank 30 includes: an inlet through which the coating liquid is made to flow in from the coating liquid tank; an outlet through which the coating liquid is made to flow out to the inkjet head; a surface-flexible film arranged so that the position of the surface-flexible film can be changed almost in the gravitational direction according to the volume of the coating liquid to be stored; a coating liquid discharge port arranged in the position higher than those of the inlet and the outlet in the gravitational direction; a stop valve for controlling the start/stop of the discharge of the coating liquid from the coating liquid discharge port; and a chamber for decompressing/pressurizing the surface-flexible film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is mainly used in the field of manufacturing color filters for color liquid crystal displays, and more specifically, an inkjet head related to forming a color filter by discharging R, G, and B coating liquids with an inkjet head. The present invention relates to an improvement in a coating solution supply apparatus, a coating solution supply method, and a color filter manufacturing method.

The color liquid crystal display includes a color filter, a TFT array substrate, and the like. In this color filter, each pixel bordered by a grid-like black matrix on a glass substrate is regularly formed by dividing it into three colors of R (red), G (green), and B (blue). It is the member which makes the center of the color formation of the display. This color filter is usually
1) After forming a coating film of a black photoresist material on a glass substrate, the black coating film is processed into a lattice shape by photolithography (formation of a lattice-shaped black matrix),
2) Once the R coating film is formed on the entire surface, the R coating film is left only on the R pixels between the lattices by photolithography (R pixel formation).
3) For G and B, the coating films of B and G are once formed on the entire surface by the same method as R, and then the B and G coating films are left only on the B and G pixels (B and G pixel formation).
It is manufactured by. In forming the R, G, and B pixels by the above-described photolithography method, many processes such as R, G, and B whole surface coating film formation, exposure, and development are required.

  In recent years, in order to simplify this, only R, G, and B coating liquids are directly supplied to the pixel portion formed by a black matrix lattice by an inkjet head to form R, G, and B color pixels. The technique to do is becoming industrially performed (for example, refer patent document 1). This method of forming R, G, and B pixels using an inkjet head does not require steps such as exposure and development, and uses only the amount of coating liquid necessary for color pixel formation, enabling a significant cost reduction in color filter manufacturing. To do.

  In order to form a color pixel by discharging a coating liquid over a long period of time with an inkjet head, a system for continuously supplying the coating liquid to the inkjet head is required. A typical example is that a main tank, an intermediate tank, also called a sub tank, and an ink jet head are fluidly connected by piping, and the main tank coating liquid is applied to one or several substrates by an ink jet head. Is sent to the intermediate tank and stored (see, for example, Patent Document 2). Looking at the inside of the intermediate tank, the coating liquid on the lower side and air on the upper side are separated, and even if the coating liquid containing bubbles is sent from the main tank side, it is absorbed by the air layer in the intermediate tank. It is possible to feed only the coating liquid without bubbles to the downstream inkjet head, and to avoid problems with the inkjet head due to bubbles.

  By the way, the coating liquid in the inkjet head needs to be maintained at a negative pressure of −0.5 to 1 kPa so that the coating liquid does not leak from the inkjet head. In Patent Document 2, the upstream side of the intermediate tank is blocked by a valve, and the intermediate tank is disposed below the inkjet head in the gravity direction by a head difference corresponding to a negative pressure of −0.5 to 1 kPa. A predetermined negative pressure is applied to the coating liquid filling the ink jet head. In some cases, an intermediate tank in which the coating liquid and air are separated reduces the air side to a predetermined negative pressure to apply a predetermined negative pressure to the coating liquid between the intermediate tank and the inkjet head.

  In this way, the coating liquid in the intermediate tank is allowed to stand for a while until it is fed to the inkjet head while receiving a negative pressure of atmospheric pressure or −0.5 to 1 kPa. In many cases, the air dissolved in the coating liquid foams into a gas.

  However, since the intermediate tank has an air layer on the coating solution, even if air appears from the coating solution, it rises in the coating solution and is absorbed by the air layer. As a result, since the coating liquid is not sent from the intermediate tank to the ink jet head, only the coating liquid is sent, so that troubles of the ink jet head due to dissolved air can be avoided.

  However, in this known type of intermediate tank, the coating liquid in contact with the air layer stays almost without moving, and the coating liquid deteriorates due to agglomeration of coloring pigments with the passage of time, and the deteriorated product is an inkjet head. When mixed with the coating solution supplied to the coating film, quality problems such as color grain defects due to aggregates are often caused in the coating film. Furthermore, when this type of intermediate tank is moved together with the jet head and the coating liquid is ejected onto a stationary substrate to form a coating film, the coating liquid in contact with the air layer in the intermediate tank is rippled, There is also a problem that the negative pressure fluctuates and the coating liquid discharge amount from the ink jet head fluctuates, resulting in large film thickness unevenness.

  In order to prevent quality deterioration and film thickness unevenness due to the contact of the coating liquid with air, there are some which fill only the coating liquid without allowing air to enter the main tank, the valve, the intermediate tank, and the inkjet head. In the present invention, the intermediate tank is formed of a flexible resin bag so that the coating liquid storage amount of the intermediate tank can be changed every moment, and a suction pressure is applied to the bag from a vacuum pump so that the inside of the ink jet head. A predetermined negative pressure is applied to the coating liquid (see, for example, Patent Document 3). In this system, the quality of the coating solution is further stabilized.

  However, with the means shown in Patent Document 3, even if air mistakenly mixed with the coating liquid in the main tank is sent to the intermediate tank, the intermediate tank does not have an air layer that absorbs the air. Therefore, the intermediate tank accumulates air. Further, as in the conventional system, the coating liquid in the intermediate tank is temporarily stored under a negative pressure, so that the dissolved air in the coating liquid is in a state of being easily bubbled. Once air appears in the coating solution, there is no portion that absorbs the air, so air accumulates in the intermediate tank.

  If the air accumulated in the intermediate tank is mixed into the coating liquid as bubbles and sent to the inkjet head as it is, troubles due to bubbles are caused in the inkjet head. Here, the most common trouble caused by bubbles in the inkjet head is that the coating liquid is blocked by the bubbles and is not discharged from the discharge holes of the inkjet head. Therefore, in order to put the means of Patent Document 3 into practical use, the coating liquid is defoamed before filling the main tank, or before the intermediate tank so that the dissolved air in the coating liquid is not bubbled by negative pressure. It was necessary to provide a deaeration device for deaeration. For this reason, the equipment becomes complicated, and problems such as deterioration of the coating solution represented by a decrease in the amount of solvent due to deaeration occur, and the means of Patent Document 3 is not utilized.

  In addition, there is an intermediate tank provided with a porous film at the top of the storage section that fills the storage section with only the coating liquid so that the coating liquid and air do not contact, and allows gas to pass through but blocks the liquid (for example, Patent Documents). 4). In this intermediate tank, by sucking from the porous membrane side, a predetermined negative pressure can be applied to the coating liquid in the intermediate tank, and even if dissolved air in the coating liquid is bubbled, Air bubbles can be discharged to the outside.

However, since the coating solution around the porous film stays, the coating solution deteriorates due to the aggregation of colored pigments over time, and the deteriorated product is mixed with the coating solution supplied to the inkjet head, and the coating is performed. It is inevitable that the film causes quality problems such as color grain defects due to aggregates.

As described above, there are no known intermediate tanks that can solve the quality deterioration due to the contact between the air and the coating liquid and the retention of the coating liquid, and the quality problems and inconveniences caused by the air and dissolved air mixed in the coating liquid. It is.
JP 2006-209140 A (paragraphs 0019 to 0031, FIG. 1) Japanese Patent Laying-Open No. 2007-330923 (paragraphs 0031 to 0040, FIG. 1) JP 2007-176090 A (paragraphs 0037 to 0062, FIGS. 1, 3, and 4) JP 2008-74050 A (paragraphs 0027 to 0031, FIGS. 1, 2, and 3)

  The present invention has been made on the basis of the above-mentioned circumstances, and the object of the present invention is a supply device that fills only the coating liquid without allowing air to enter the main tank, the valve, the intermediate tank, and the inkjet head. Even if there is insufficient defoaming of the coating liquid and dissolved air becomes bubbles in the coating liquid, these air is discharged outside the system without adding a deaerator to the inkjet Does not cause air bubbles in the head. Another object of the present invention is to provide a coating liquid supply apparatus and a supply method for an inkjet head capable of maintaining the quality of the coating liquid over a long period of time by eliminating quality deterioration due to the retention of the coating liquid. Furthermore, it is providing the manufacturing method of the color filter which can manufacture a high quality color filter at low cost using said coating liquid supply method of an inkjet head.

  The object of the present invention is achieved by the means described below.

  A coating liquid supply device for an inkjet head according to the present invention includes an inkjet head that discharges a coating liquid, a coating liquid tank that is filled with the coating liquid, and a temporary filling by filling the coating liquid between the coating liquid tank and the inkjet head. A coating liquid supply device for an ink jet head, comprising: an intermediate tank capable of storing a constant volume; and a valve for transferring / stopping the coating liquid from the coating liquid tank to the intermediate tank. An inlet through which the coating liquid from the tank flows, an outlet through which the coating liquid flows out to the ink jet head, a surface flexible film arranged so that its position can be changed in a substantially gravitational direction according to the volume of the coating liquid to be stored, and the inlet A coating liquid discharge port disposed above the outlet in the direction of gravity, an open / close valve for controlling discharge / stop of the coating liquid from the coating liquid discharge port, and the surface flexible film Characterized in that it comprises a chamber for applying pressure / pressure, the.

  Here, the surface flexible film of the intermediate tank is further disposed below the coating liquid in the gravity direction, and further includes switching means for switching between pressure reduction / pressurization applied to the chamber of the intermediate tank. It is preferable.

The inkjet head coating liquid supply method of the present invention is a method of supplying the coating liquid from the coating liquid tank to the inkjet head through an intermediate tank having a surface flexible film on the lower side in the gravity direction,
Injecting the coating liquid into the intermediate tank from an inlet;
Discharging air bubbles and / or the coating liquid in the intermediate tank from the outlet in the gravity direction above the inlet and outlet of the intermediate tank;
A step of supplying the coating liquid from the outlet of the intermediate tank to the inkjet head in a state in which a negative pressure is applied to the intermediate tank.

  Here, the step of discharging the coating liquid is preferably a step of pressurizing the surface flexible film of the intermediate tank from the atmosphere side.

  The color filter manufacturing method of the present invention is characterized in that a color filter is manufactured using the coating liquid supply method for an inkjet head described above.

  By using the coating liquid supply device and the coating liquid supply method of the inkjet head according to the present invention, air mixed in by mistake from the coating liquid discharge port at the top of the intermediate tank, which is a sub tank equipped with a surface flexible film, Since the dissolved air of the liquid is bubbled, it can be discharged together with the coating liquid, so that bubbles are not sent from the intermediate tank to the inkjet head. As a result, there is an effect that bubbles are not caused by the ink jet head.

  Further, since the discharge of bubbles can be performed without adding a new device such as a deaeration device, the device is not complicated, and the device can be provided at a low cost. Furthermore, since the coating liquid is periodically discharged from the coating liquid discharge port at the upper part of the intermediate tank, the coating liquid that stays for a certain period of time must be discharged outside the system, and the coating liquid stays for a long time. The quality problem caused by can be eliminated.

  As described above, since the coating liquid can be supplied from the intermediate tank to the inkjet head without contacting the air from the main tank and with a predetermined negative pressure, the coating liquid is deteriorated by the air contact. In addition, the quality of the coating solution can be easily maintained without dissolving new air. As a result, there is no occurrence of coating defects due to deteriorated substances when forming color pixels by the ink jet head. Further, when the intermediate tank of the present invention is moved together with the jet head and the coating liquid is formed by discharging the coating liquid onto a stationary substrate, the coating liquid does not swell in the intermediate tank, so the negative pressure is constant. In addition, the amount of coating liquid discharged from the ink jet head can be stabilized, and the film thickness unevenness can be made substantially zero.

  According to the color filter manufacturing method of the present invention, a color filter is manufactured using the above-described excellent inkjet head coating liquid supply method. As a result, a high-quality color filter that is low in cost, excellent in uniformity and reproducibility of the coating film, and free from coating defects due to deteriorated materials can be easily manufactured with high productivity.

  FIG. 1 is a schematic front view of a coating liquid supply apparatus 1 according to the present invention, FIG. 2 is a schematic plan view of an intermediate tank 30, and FIG. 3 is a schematic front sectional view showing a filling state of the coating liquid in the intermediate tank 30. 4 is a schematic front sectional view showing a filling state of another coating liquid in the intermediate tank 30.

  First, referring to FIG. 1, a coating liquid supply device 1 for an inkjet head 100 according to the present invention and a substrate A disposed on an adsorption stage 80 coated from the inkjet head 100 by the coating liquid supply device 1 are shown. . The suction stage 80 is driven by a drive source (not shown) by a pair of rails 84 and guides 82 that extend in one direction, and can move freely in one direction.

The coating liquid supply apparatus 1 includes a main tank 10 that is a coating liquid tank filled with a coating liquid 72 and an intermediate tank that is a sub-tank that temporarily stores the coating liquid 72 sent from the main tank 10 via a pipe 28. 30, a valve 29 for transferring / stopping the coating liquid in the middle of a pipe 28 that fluidly connects the main tank 10 and the intermediate tank 30, and a fluid connection between the intermediate tank 30 and the inkjet head 100. The pipe 76 is configured to allow the coating liquid stored in the tank 30 to be transferred to the inkjet head 100.

  The inkjet head 100 is provided with a large number of ejection holes, and the coating liquid 72 supplied from the pipe 76 is distributed to the ejection holes substantially evenly within the inkjet head 100, and piezoelectric elements arranged in the vicinity of the ejection holes. By a drive member made of, etc., it is discharged substantially uniformly from the discharge holes.

  The main tank 10 has a bag member 12 in which a coating liquid 72 is built in a main body 18 which is a metal can. The bag member 12 is made of resin, has flexibility, and can be freely deformed depending on the amount of the coating solution contained therein, and the connection member 14 is joined to an opening at one end thereof. The connecting member 14 seals and holds the elongated tube 16 that reaches the bottom of the bag member 12. One end of a pipe 28 is connected to the tube 16. Inside the main body 18, pressurized air supplied from a pressure air source 24 and adjusted to a predetermined pressure by the pressure regulator 22 is introduced through the open / close valve 26 and the pipe 20. Therefore, when the opening / closing valve 26 is opened and the outside of the bag member 12 is pressurized with pressurized air, the bag member 12 is deformed inward and the built-in coating liquid 72 is fed to the pipe 28 through the tube 16. .

  The intermediate tank 30 has a main body 32 in which a manifold 50 for storing a coating solution is formed, and has a flexibility that is disposed at a position that covers the entire manifold 50 when viewed from above. The resin film 34 and the end portion of the resin film 34 are sandwiched between the main body 32 and fixed to the holding member 46 and the holding member 46 that form a space 54 with the resin film 34. 50 is constituted by a full sensor 42 for detecting the limit of the amount of liquid stored in 50. The gravity direction is a vertical direction Z in which the direction in which gravity acts is indicated by an arrow in FIG.

  Here, the shape of the upper side in the gravity direction of the manifold 50 is defined by a wall surface 92 provided in the main body 32. The manifold 50 is defined as a portion where the coating liquid is stored between the wall surface 92 and the resin film 34, and can be said to be a coating liquid storage section. Since the manifold 50 is filled with the coating liquid 72 indicated by oblique lines, the resin film 34 is disposed below the coating liquid 72 in the gravity direction, that is, in the vertical direction. As a result, the opposite surface of the resin film 34 that contacts the coating liquid 72, that is, the lower surface of the resin film 34 in the gravitational direction is in contact with the atmosphere, and is therefore defined as the atmosphere. The main body 32 and the holding member 46 are fastened by a fastening member (not shown).

  Further, an inlet 39 and an outlet 41 are provided at both ends of the manifold 50 in the horizontal direction. The inlet 39 is on the downstream side of the inlet pipe 38, the outlet 41 is on the upstream side of the outlet pipe 40, and the inlet pipe 38 is connected to the pipe 28 and the outlet pipe 40 is connected to the pipe 76, respectively. Accordingly, the coating liquid from the main tank 10 flows into the manifold 50 from the inlet 39 through the pipe 28 and the inlet pipe 38, and then flows out from the outlet 41, and travels toward the inkjet head 100 through the outlet pipe 40 and the pipe 76. The inlet pipe 38 and the outlet pipe 40 are fixed to the main body 32.

  Further, the manifold 50 is provided with a discharge pipe 60 having an outlet 70 above the inlet 39 and outlet 41 in the direction of gravity. The outlet 70 serves as a coating solution discharge port, and is preferably disposed at the uppermost part in the gravity direction as shown in FIG. The manifold 50 also preferably has a tapered shape in which a wall surface 92 defining its contour converges toward the outlet 70 of the discharge pipe 60. This is because all the coating liquid and air in the manifold 50 can be concentrated in the discharge pipe 60 and discharged to the outside from the tip 50 of the manifold 50.

  A pipe 62 is connected to the discharge pipe 60, and a valve 64 is connected on the downstream side of the pipe 62 and finally extends to the drainage tank 68. The valve 64 is a normal open / close valve, and the coating liquid discharged from the discharge pipe 60 is stored as the drain 66 in the drain tank 68 when the valve 64 is open. It is preferable that the drainage tank 68 is disposed below the discharge pipe 60 in the direction of gravity because the coating liquid discharged from the discharge pipe flows smoothly by siphon action.

  Further, when the manifold 50 is viewed from the lower side, it has an elongated shape in the direction from the inlet 39 to the outlet 41 as shown in FIG. In the center, the outlet 70 of the discharge pipe 60 is visible. Such a long and narrow shape is preferable because the retention of the coating liquid in the direction of the arrow is reduced. In order to reduce the stagnation of the coating liquid in the vicinity of the inlet 39 and the outlet 41, the channel width gradually changes gradually from the center of the manifold 50 toward the inlet 39 and the outlet 41 as shown in FIG. You may make it a shape to do.

  Further, referring to FIG. 1, a pipe 44 is connected to the holding member 46 so as to reach a space 54 formed between the resin film 34 and the holding member 46. The opposite side of the space 54 of the pipe 44, that is, the upstream side, is bifurcated in the middle. The valve 56, the vacuum pressure regulator 45, and the vacuum pump 48 are on one side, and the valve 58 and the pressure regulator 74 are on the other side. And a compressed air source 78 are connected.

  If the valve 56 is opened and the valve 58 is closed, the pipe 44 can make the space 54 have any negative pressure Pv adjusted by the vacuum pressure regulator 45, and the valve 56 is closed and the valve 58 is opened. In this case, the compressed air from the compressed air source 78 can be supplied to the space 54 at an arbitrary pressure Pp by the pressure regulator 74. By setting the space 54 to an arbitrary negative pressure Pv, it is possible to apply a negative pressure substantially equal to the negative pressure Pv to the coating liquid 72 filled in the intermediate tank 30 through the resin film 34.

  Further, by supplying compressed air having an arbitrary pressure Pp to the space 54, the resin film 34 can be moved upward and the coating liquid 72 in the manifold 50 can be discharged to the outside of the intermediate tank 30. That is, the intermediate tank 30 can be operated as an intermittent constant capacity pump. The valve 56 and the valve 58 act as switching means for setting the space 54 to a negative pressure or a positive pressure, that is, switching between depressurization / pressurization. Thus, the space 54 becomes a chamber provided in the holding member 46 in order to depressurize / pressurize the resin film 34 having surface flexibility defined below.

  When the negative pressure Pv is applied to the space 54, the position of the resin film 34 is moved according to the balance of the pressure applied to the coating liquid on the manifold 50 side. The resin film 34 is in a so-called “sagging” state, and its position can be freely moved to both the manifold 50 side and the space 54 side without elastic deformation due to expansion and contraction. The fact that the planar body such as the resin film 34 can be moved freely as a surface without elastically deforming is referred to as “surface flexible”.

Accordingly, the resin film 34 can be said to be a surface flexible film, that is, a film having surface flexibility. In the intermediate tank 30, the resin film 34 is disposed so as to move in a substantially gravitational direction, that is, the vertical direction in FIG. 1. The resin film 34 preferably has surface flexibility and strength and is resistant to the coating liquid, and is a resin such as Teflon (registered trademark), PET, polyethylene, and preferably has a thickness of 10 to 500 μm. The thing of 50-150 micrometers is preferably used. Since the resin film 34 has the above configuration, even if the amount of the coating liquid stored in the manifold 50 changes while the negative pressure Pv is applied to the space 54, the resin film 34 follows the change in the amount of the coating liquid. Since the position moves, the negative pressure acting on the coating liquid 72 does not change and has a characteristic of being substantially constant.

  Next, a coating liquid supply method using the coating liquid supply apparatus 1 of FIG. 1 will be described with reference to FIG. FIG. 3 shows only the intermediate tank 30 and the pipes and valves before and after connecting to the intermediate tank 30 in the coating liquid supply apparatus 1. The empty pipe is indicated by a thin line, the pipe filled with the coating liquid is indicated by a thick line, the air inside the intermediate tank 30 is indicated by white, and the coating liquid is indicated by a diagonal line. In addition, a valve that is illustrated with only a line segment indicates a “closed state”, and a valve that is painted black and marked with “open” on the side indicates an “open state”.

  First, the main tank 10 is connected without any coating liquid 72 from the pipe 28 to the inkjet head 100 in an empty state, and the coating liquid supply method at the start of supplying the coating liquid 72 starts supplying the coating liquid 72 in the main tank 10. Will be described. At this time, as shown in FIG. 3A, the inside of the intermediate tank 30 is still air without any coating liquid in the intermediate tank 30.

  With the valve 56 opened and the valve 58 closed, a force directed toward the outside of the intermediate tank 30 is applied to the pipe 44 by suction from the vacuum pump 48 and pressure adjustment by the vacuum pressure regulator 45, and the space 54 has a predetermined negative pressure Pv. It has become. With the resin film 34 as a boundary, the manifold 50 side is at atmospheric pressure, and the space 54 side is at negative pressure Pv. Therefore, the resin film 34 is attracted to the space 54 side and is at a position where pressure can be balanced and is stationary. . The valve 64 connected to the discharge pipe 60 may be opened or closed, but is preferably opened so that the air in the manifold can be easily discharged to the outside.

  In this state, the opening / closing valve 26 is opened, and the pressurized air that has been adjusted to a predetermined pressure by the pressure regulator 22 is sent into the main body 18 of the main tank 10. Next, when the valve 29 is opened, the bag member 12 in the main tank 10 is pressurized from the outside, and the internal coating liquid 72 is sent toward the pipe 28. First, air enters the intermediate tank 30, and then the coating liquid 72 flows from the inlet pipe 38.

  Part of the air in the intermediate tank 30 travels from the outlet pipe 40 to the inkjet head 100 through the pipe 76. This air is discharged from the ejection holes of the inkjet head 100 to the outside. The remaining part of the air in the intermediate tank 30 is discharged from the discharge pipe 60 to the outside. However, some air remains in the upper portion of the manifold 50 and becomes the air reservoir 94 as shown in FIG. In such a state, even if the coating liquid 72 is supplied to the intermediate tank 30 from the upstream side, the state does not change.

  Therefore, when the state shown in FIG. 3B is reached, the valve 29 is once closed, and the supply of the coating liquid 72 from the upstream side to the intermediate tank 30 is stopped. Subsequently, the valve 56 is closed, the compressed air from the compressed air source 78 is adjusted to a predetermined pressure Pp by the pressure regulator 74, the valve 58 is opened, and the piping 44 is directed toward the space 54 in the intermediate tank 30. Compressed air with a pressure Pp is supplied. By this operation, the resin film 34 starts to move upward in the direction of gravity, whereby the coating liquid in the manifold 50 also moves upward. Accordingly, the air reservoir 94 staying at the upper portion of the manifold 50 also moves upward, and is discharged from the discharge pipe 60 to the outside of the intermediate tank 30 through the pipe 62.

  When the air passes through the valve 64 downstream of the discharge pipe 60 and the coating liquid pushed out from the manifold 50 passes through the valve 64 as shown in FIG. 3C, the valves 64 and 58 are closed substantially simultaneously. Alternatively, the valve 58 is closed after the valve 64 is closed. By this time, a part of the coating liquid 72 in the manifold 50 has also flowed from the outlet pipe 40 to the pipe 76, so that the air remaining in the pipe 76 from the outlet pipe 40 flows to the inkjet head 100 side. Moving. By the above operation, at least all the air remaining in the manifold 50 is discharged to the outside.

  Subsequently, the valve 56 and the valve 29 are opened substantially simultaneously, or the valve 29 is opened and then the valve 56 is opened, and a force toward the outside of the intermediate tank 30 is applied to the pipe 44 to apply the negative pressure Pv to the space 54. Then, the coating liquid 72 is supplied from the main tank 10 to the intermediate tank 30. As a result, the coating liquid 72 flowing in from the inlet pipe 38 is directed toward the resin film 34 and moves a part of the resin film 34 downward in the gravity direction.

  As the resin film 34 moves to the lower limit position and the coating liquid 72 is filled in the intermediate tank 30, the coating liquid 72 flows from the outlet pipe 40 toward the pipe 76. Accordingly, the air remaining in the pipe 76 and the ink jet head 100 is all discharged to the outside from the ejection holes of the ink jet head 100 in a form pushed by the coating liquid 72 coming from the upstream side. Then, as shown in FIG. 3D, the coating liquid is filled from the main tank 10 to the inkjet head 100.

  During the air discharge operation, the resin film 34 moves to the lower side in the substantially gravity direction, and may reach the lower limit position when the coating liquid is filled. Normally, the full position sensor 42 detects this lower limit position in a non-contact manner, thereby knowing the full state and closing the valve 29 so that the coating liquid 72 does not further flow into the intermediate tank 30. However, only at the time of the first air exhausting work, the remaining air in the pipe 76 and the ink jet head 100 is completely replaced with the coating liquid 72 after a certain period of time after the full sensor 42 knows that the lower limit position of the resin film 34 has been reached. Then, the valve 29 is closed.

  When the full sensor 42 detects that the resin film 34 has reached the lower limit position, the valve 29 is once closed to stop the supply of the coating liquid 72 to the intermediate tank 30 and then the valve 56 is closed. The valve 58 may be opened, the resin film 34 may be moved upward, and the coating liquid stored in the manifold 50 may be sent to the inkjet head 100 side.

  This also allows the air remaining in the pipe 76 and the inkjet head 100 to be pushed out and discharged. In this case, the intermediate tank 30 operates as a pump for the coating liquid 72. That is, since the distance between the intermediate tank 30 and the ink jet head 100 is much shorter than the distance between the main tank 10 and the ink jet head 100, the intermediate liquid can be supplied at a higher supply speed than the application liquid supply speed by pressure feeding from the main tank 10. The coating liquid can be supplied from the tank 30 to the inkjet head 100. As a result, the air in the pipe 76 and the inkjet head 100 can be discharged in a shorter time.

  Even after the resin film 34 reaches the lower limit position, the valve 29 is opened and the coating liquid 72 in the main tank 10 is pumped from the main tank 10 or the resin film 34 is moved by compressed air at the pressure Pp. During this time, a positive pressure is applied to the coating liquid 72 in the intermediate tank 30. After the valve 29 is closed, or after the valve 58 is closed and the supply of the compressed air with the pressure Pp to the resin film 34 is stopped, the coating liquid 72 is filled from the main tank 10 to the inkjet head 100. If so, the coating liquid 72 is discharged from the inkjet head 100 by a positive residual pressure acting on the coating liquid 72 in the intermediate tank 30 and then returned to atmospheric pressure.

Subsequently, when the valve 56 is opened, the negative pressure Pv is applied to the space 54, and the resin film 34 is attracted to the space 54 side by the attractive force. Therefore, the coating liquid 72 in the inkjet head 100 is also applied to the resin film 34 from the intermediate tank 30. 34. As a result, a negative pressure substantially equal to the negative pressure Pv acting on the space 54 acts on the coating liquid 72 filling the intermediate tank 30. Incidentally, when the resin film 34 of the intermediate tank 30 is above the ejection hole of the ink jet head 100 in the gravity direction, the negative pressure Pn acting on the coating liquid 72 in the ink jet head 100 is reduced by the resin film 34 of the intermediate tank 30. The head differential pressure H acting between the ejection holes of the inkjet head 100 is added to the negative pressure Pv in the intermediate tank 30 to become Pv + H.

This negative pressure Pn is
1) Prevent the coating liquid 72 from leaking from the ejection holes of the inkjet head 100;
2) Hold the liquid film at the discharge hole after discharging the coating liquid 72 from the inkjet head 100 to prevent air from entering from the discharge hole;
3) It is necessary for stably discharging the coating liquid from the discharge hole. The magnitude of the negative pressure Pn acting on the coating liquid 72 filling the ink jet head 100 is preferably −0.5 to 1 kPa. If it is smaller than this range, the coating liquid 72 leaks out from the ejection holes of the inkjet head 100, and if it is larger than this range, air is sucked from the ejection holes.

  Further, when the resin film 34 of the intermediate tank 30 is below the ejection hole of the inkjet head 100 in the gravity direction, the negative pressure Pn acting on the coating liquid 72 in the inkjet head 100 is reduced by the resin film of the intermediate tank 30. The head differential pressure H acting between the ejection holes of the inkjet head 100 from 34 is subtracted from the negative pressure Pv in the intermediate tank 30 to Pv−H.

  The lower limit position of the resin film 34 is preferably in a state where a slight slack is left in the resin film 34. When the coating liquid 72 is supplied to the intermediate tank 30 in a state in which the sagging of the resin film 34 disappears and is in tension, the resin film 34 starts to be elastically deformed and the reaction force acts on the coating liquid 72 in the manifold 50 as a positive pressure. This is because the negative pressure Pv cannot be maintained.

  Next, referring to FIG. 4, as shown in FIG. 4A, the coating liquid 72 is filled from the main tank 10 to the inkjet head 100, the valve 29 is closed, the valve 64 is closed, the valve 56 is opened, and the piping 44. When a negative pressure Pv is applied to the space 54 by applying a force toward the outside of the intermediate tank 30, air is mixed for some reason and the method of supplying the coating liquid 72 from the intermediate tank 30 to the inkjet head 100. A method for supplying the coating liquid 72 including the air discharging method in this case will be described.

  When the coating liquid is ejected from the inkjet head 100 from the state of FIG. 4A, the coating liquid 72 stored in the intermediate tank 30 is applied from the inkjet head 100 side by a suction force larger than the negative pressure Pv. 100. As a result, the amount of the coating liquid 72 stored in the intermediate tank 30 decreases, and the position of the resin film 34 moves correspondingly to the upper side in the substantially gravitational direction, and finally reaches the upper limit position as shown in FIG. ), The storage amount is minimum.

  The upper limit position of the resin film 34 is preferably in a state where some slack is left in the resin film 34. When the sag of the resin film 34 disappears and it becomes a tense state, the position cannot be moved corresponding to the suction force from the ink jet head 100 side, and a negative pressure much larger than the negative pressure Pv acts on the coating liquid. This is because air is generated by cavitation. From FIG. 4A to FIG. 4B, the volume change amount Vc of the coating liquid stored in the manifold 50 is the amount of consumed coating liquid that can substantially hold the negative pressure Pv, that is, from the intermediate tank 30 to the inkjet head 100. It becomes a coating liquid supply amount. The magnitude of the capacitance change amount Vc is preferably about 1.1 to 2.0 times the amount of coating liquid required for one processing operation of the inkjet head 100, for example, formation of color pixels on one substrate.

On the other hand, the magnitude of the negative pressure Pn acting on the coating liquid 72 in the inkjet head 100 is also affected by the position change of the resin film 34 in the gravity direction. That is, if the resin film 34 moves upward from the current position, the negative pressure Pn acting on the coating liquid 72 in the inkjet head 100 is reduced by an amount corresponding to the head differential pressure of the coating liquid 72. Conversely, if the resin film 34 moves downward from the current position, the negative pressure Pn acting on the coating liquid 72 in the inkjet head 100 increases by an amount corresponding to the head differential pressure of the coating liquid.

  If the density of the coating liquid 72 is 1, the pressure acting on the coating liquid 72 in the inkjet head 100 changes by 0.01 kPa when the resin film 34 moves 1 mm in the gravity direction. Therefore, when the pressure change acting on the coating liquid is 0.1 kPa or less, the shape of the manifold 50 is such that the amount of position movement in the gravitational direction of the resin film 34 when the volume change amount Vc of the coating liquid is 10 mm or less. And the amount of sag of the resin film 34 is determined.

  When the position movement direction of the resin film 34 coincides with the direction of gravity, the pressure change acting on the coating liquid due to the position movement of the resin film 34 is minimized. When the intermediate tank 30 is tilted from the state of FIG. 4A and the main direction of position movement of the resin film 34 is tilted by θ (not shown) from the direction of gravity, the pressure change value derived by the position movement in the direction of gravity is obtained. The value divided by the cosine value of θ is the pressure change value at that time. In particular, when the main direction of the position movement of the resin film 34 is the horizontal direction, the pressure acting on the coating liquid changes greatly due to the slight position movement of the resin film, and therefore the inkjet coating liquid supply apparatus that needs to reduce the pressure change. Can not be used. Therefore, as an inkjet coating liquid supply device, the resin film 34 of the intermediate tank 30 is moved most approximately in the direction of gravitational force, and the pressure change acting on the coating liquid accompanying the position movement is most preferable.

  Here, the substantially gravitational direction refers to a range of inclination of ± 10 degrees or less with respect to the gravitational direction.

  Now, in order to perform the next processing operation of the inkjet head 100 from the state of FIG. 4B, it is necessary to replenish the coating liquid 72 into the intermediate tank 30. Therefore, the valve 29 is opened and the coating liquid 72 is fed into the intermediate tank 30 by pressure from the main tank 10. When the full sensor 42 detects that the coating liquid 72 is full, the valve 29 is closed and the coating liquid is closed. Is stopped and the state shown in FIG. 4A is obtained again. At this time, the application liquid 72 does not flow from the intermediate tank 30 toward the pipe 76 until the application liquid is filled in the intermediate tank 30, and the pressure acting on the application liquid 72 in the intermediate tank 30 is also negative pressure Pv. Is maintained. This is because the position of the resin film 34 can be moved with less force than sending the coating liquid 72 to the pipe 76, and the coating liquid 72 can be stored in the manifold 50.

  Even when the supply of the coating liquid 72 from the intermediate tank 30 to the ink jet head 100 and the replenishment of the coating liquid 72 from the main tank 10 to the intermediate tank 30 are repeated, the coating liquid at the upper part in the gravity direction in the manifold 50. 72 is staying still with the negative pressure Pv applied. Therefore, the air dissolved in the coating liquid 72 is expressed and becomes a bubble 90, and accumulates on the wall surface 92 of the main body 32 above the manifold 50 as shown in FIG. Further, even if bubbles are mixed in from the upstream side of the intermediate tank 30 for some reason, they are once trapped in the manifold 50, but rise in the manifold 50 in the same way, toward the discharge pipe 60 at the top of the manifold 50. On the other hand, in a severe case, as shown in FIG. 4C, a section from the upper part of the discharge pipe 60 to the valve 64 becomes an air reservoir 94 in which many bubbles gather.

  In order to discharge the bubbles 90 and the air reservoir 94 to the outside, the coating liquid 72 is supplied from the main tank 10 to the intermediate tank 30, and when the resin film 34 is at the lower limit position, that is, the coating liquid 72 in the intermediate tank 30. When the valve is full, the valve 29 is closed, the valve 56 is closed, and then the valve 58 and the valve 64 are opened substantially simultaneously, or the valve 58 is opened and then the valve 64 is opened. By supplying the compressed air with the pressure Pp to the space 54, the resin film 34 is moved upward.

  As a result, the resin film 34 operates as a pump. Together with the coating liquid 72 staying in the manifold 50, the bubbles 90 and the air reservoir 94 remaining on the top of the manifold 50 are passed through the exhaust pipe 60 and the valve 64. As shown in FIG. 4D, the intermediate tank 30 is finally filled with only the coating liquid. The valve 64 is closed and the valve 58 is closed until the resin film 34 reaches the upper limit position after a certain period of time after the bubble 90 or the air reservoir 94 is pushed downstream from the valve 64.

  Subsequently, the valve 56 is opened and a negative pressure Pv is applied to the space 54, then the valve 29 is opened, the coating liquid 72 is supplied from the main tank 10 to the intermediate tank 30, and the lower limit of the resin film 34 is reached by the full sensor 42. When the position is detected, the valve 29 is closed. Thereafter, the supply of the coating liquid 72 from the intermediate tank 30 to the inkjet head 100 is resumed in the same manner as described above. The coating liquid discharged from the exhaust pipe 60 to the outside of the intermediate tank 30 is stored in the drainage tank 68 as the drainage liquid 66, but bubbles pushed out to the coating liquid 72 are discharged from the pipe 62 to the drainage tank 68. It passes through the liquid 66 and is discharged to the atmosphere.

  It is preferable to periodically perform the operation of discharging the coating liquid 72 and bubbles remaining in the manifold 50. The frequency may be determined by time, or may be determined by the number of times the coating liquid is supplied to the intermediate tank 30 or the inkjet head 100. Since the coating liquid staying regularly is discharged to the outside, it is possible to prevent the coating liquid deteriorated by the retention from being mixed into a normal coating liquid and causing a coating quality problem. The operation of adding compressed air of pressure Pp to the resin film 34 to move the resin film 34 to the upper limit position and discharging the bubbles 90 and the air reservoir 94 together with the coating liquid 92 to the outside of the intermediate tank 30 through the discharge pipe 60 is as follows. As described above, it may be performed only once, or the intermediate tank 30 may be replenished with the coating liquid 72 from the main tank 10 and repeated a plurality of times.

  Air is always dissolved in the coating solution, and the dissolved air becomes bubbles where negative pressure acts on the coating solution. As described above, the negative pressure acts on the coating liquid in the section from the intermediate tank 30 to the pipe 76 to the inkjet head 100, but the coating liquid 72 is temporarily left in a state where the negative pressure is applied to the intermediate tank 30. In this case, the dissolved air is bubbled as much as possible so as not to be bubbled in the pipe 76 or the inkjet head 100 downstream from the intermediate tank 30 to prevent inconveniences such as quality defects due to bubbles and defective ejection of the inkjet head. This is the eye of the present invention.

  Therefore, it is said that the larger the amount of the coating liquid to be left standing, that is, the staying in the manifold 50 in the intermediate tank 30, and the longer the standing time, that is, the longer the staying time is, the more the dissolved air in the coating liquid is bubbled. However, since the coating solution deteriorates due to pigment aggregation due to long-term residence, the amount of coating solution deteriorates when the retention amount is large, and the degree of deterioration of the coating solution increases when the residence time is long. In the present invention, the coating liquid is allowed to remain stationary in order to make dissolved air in the coating liquid into bubbles, but by discharging all of the coating liquid that has stayed for a certain period of time to the outside, quality problems due to deterioration of the coating liquid are avoided. is there.

  The larger the amount of coating solution stored in the manifold 50, the more the dissolved air in the coating solution can be bubbled to prevent problems caused by bubbles, but the amount of staying coating solution that is periodically discharged also increases. There also arises an inconvenience that the amount of invalid coating liquid that is not ejected from the head 100 increases. From the above, the maximum amount of coating liquid stored in the manifold 50 is preferably 1.1 to 3.0 times, more preferably 1.2 times the amount of coating liquid necessary for forming a color pixel on one substrate. -2.0 times.

Next, in a state where the coating liquid 72 is filled from the main tank 10 to the inkjet head 100, the coating liquid 72 in the main tank 10 disappears, and the coating liquid when the replacement is performed with the new main tank 10N fully filled with the coating liquid 72. A supply method is demonstrated based on FIG.

  When the new main tank 10N filled with the coating liquid 72 is connected to the pipe 28, air remains in the vicinity of the new tube 16N in the new main tank 10N and the connection portion of the pipe 28 with the new main tank 10N. This must be discharged to the outside. First, the pressurized air adjusted to a predetermined pressure by the pressure regulator 22 is sent to the new main tank 10N by opening the on-off valve 26, and then the valve 29 is opened. Then, the new bag member 12N in the new main tank 10N is opened. Is pressurized from the outside and feeds the internal coating liquid 72 toward the pipe 28. As a result, the air remaining in the above location moves downstream together with the coating liquid and enters the manifold 50 in the intermediate tank 30 from the inlet 38.

  Thereafter, the coating liquid is supplied to the intermediate tank 30 and the inkjet 70 in the same manner as the coating liquid supply method for starting the supply of the coating liquid from the empty state described above. Discharge from the discharge pipe 60 to the outside.

  If the system in which the air in the new tube 16N and the like is discharged and the coating liquid 72 is supplied without interruption after the new main tank 10N is connected to the pipe 28, the above coating liquid supply method is performed. In order to discharge air from the inkjet head 100, it is not necessary to interrupt the coating operation, and the supply method of the coating liquid when the coating liquid is filled up to the main tank 10 to the inkjet head 100 may be continued as it is.

  The purpose of setting the space 54 of the intermediate tank 30 to the negative pressure Pv can be achieved by correcting the head differential pressure and applying a predetermined negative pressure Pn to the coating liquid in the inkjet head 100 as described above. Therefore, the atmosphere side, that is, the lower side of the resin film 34 may be disposed at a position lower than the ejection hole of the inkjet head in the gravity direction and separated by a distance corresponding to the head differential pressure corresponding to the negative pressure Pn. . The distance corresponding to the head differential pressure is derived by the negative pressure Pn / the density of the coating liquid. In this case, a vacuum source and piping for applying a negative pressure are not necessary.

  The coating liquid supply apparatus and the coating liquid supply method of the present invention can be particularly suitably applied to a coating liquid having a viscosity of 5 to 20 mPas for an ink jet head.

  The present invention will be specifically described below with reference to examples.

Example 1
A coating liquid is supplied to the inkjet head 100 using the coating liquid supply apparatus 1 shown in FIG. The inkjet head 100 had 256 discharge holes at a pitch of 360 μm, and was able to discharge the coating liquid from each discharge hole at a capacity of 60 pl. The coating solution was an R coating solution containing an R color pigment, and had a solid content concentration of 20% and a viscosity of 10 mPaS. In the coating liquid supply apparatus 1, a main tank 10 in which a polyethylene bag member 12 containing 19 l of the R coating liquid for forming the R pixel is housed in a stainless steel main body 18 is used. The pipes 28 and 76 were made of Teflon tubes having an inner diameter of 4 mm and an outer diameter of 6 mm, and the valve 29 was a diaphragm type valve.

  For the intermediate tank 30, a Teflon film having a thickness of 0.05 mm was used as the resin film 34, and the diameters of the inlet 39 and the outlet 41 were 4 mm. The storage amount of the coating liquid in the manifold 50 was 10 ml, and the volume change amount Vc of the coating liquid determined by the upper limit position and the lower limit position of the resin film 34 was 8 ml. The wall surface 92 of the manifold 50 has a tip-drawer shape shown in FIG. 1, and the shape seen from the resin film 34 side is the shape shown in FIG.

  The outlet 70 of the discharge pipe 60 at the top of the manifold 50 is circular with a diameter of 4 mm, a diaphragm valve is used for the valve 64, and the pipe 62 connected from the discharge pipe 60 to the drainage tank 68 has an inner diameter of 4 mm and an outer diameter of 6 mm. A Teflon tube was used. In addition, the drainage tank 68 was arrange | positioned in the position below 200 mm from the up-down direction lower limit position of the resin film 34, and was able to store 0.5 liter of drainage. The intermediate tank 30 itself was disposed above the inkjet head 100 in the gravity direction, and the distance between the resin film 34 and the lower surface of the inkjet head 100 (the surface with the coating liquid discharge hole) was 400 mm.

  The negative pressure Pv acting on the space 54 is a head pressure difference H = 4 kPa between the resin film 34 and the ink jet head 100 so that the negative pressure Pn acting on the coating liquid in the ink jet head 100 becomes −0.8 kPa. Added to -4.8 kPa. The pressure Pp applied to the space 54 for operating the resin film 34 as a pump was set to 0.1 MPa.

  Next, the main tank 10 was connected without any coating liquid 72 from the pipe 28 to the inkjet head 100 and empty. In the intermediate tank 30, the valve 64 is opened, the valve 56 is opened, and the valve 58 is closed so that the negative pressure Pv acts on the resin film 34, and then a pressure of 0.1 MPa is applied to the bag member 12 of the main tank 10. While adding with compressed air, the valve | bulb 29 was opened and the coating liquid for R was supplied to the intermediate tank 30. FIG. The state in which the valve 29 was opened was continued for 5 seconds, and then the valve 29 was closed.

  At this time, part of the coating liquid was discharged together with air from the discharge hole of the inkjet head 100 and the outlet of the pipe 62. Subsequently, the valve 56 was closed and then the valve 58 was opened. The state was kept for 4 seconds, and then the valve 58 was closed. At the same time, the valve 64 was also closed. By the above operation, the coating liquid containing bubbles was discharged from the pipe 62 at first, but only the coating liquid was discharged for the last one second. As a result, it was determined that all the air remaining in the intermediate tank 30 was discharged to the outside.

  Subsequently, the valve 56 and the valve 29 were opened almost simultaneously, and the R coating liquid was supplied from the main tank 10 to the intermediate tank 30. The R coating liquid mixed with bubbles began to be discharged from the discharge holes of the inkjet head 100, and the full sensor 42 detected that the resin film 34 was the lower limit. However, the supply of the R coating liquid to the intermediate tank 30 was continued, and the valve 29 was closed 10 seconds after the valve 29 was opened.

  During the last 3 seconds, only the R coating liquid is ejected from the ejection holes of the inkjet head 100, and all the air from the pipe 76 to the ejection holes of the inkjet head 100 is expelled by the R coating liquid. It was confirmed that only the liquid was filled up to the main tank 10 to the inkjet head 100.

  Since the preparation of the coating liquid supply apparatus 1 is completed, after confirming that the valve 56 is opened and the negative pressure Pv is acting on the space 54, the inkjet head 100 is driven to use 5 ml for R each time. The coating liquid was discharged from the discharge hole. The coating liquid was discharged from all the discharge holes, and there was no discharge failure due to air. Whenever one discharge of the R coating liquid from the ink jet head 100 is completed, the valve 29 is opened to supply the intermediate tank 30 with the R coating liquid, and the full sensor 42 detects the lower limit position of the resin film 34. At that time, the valve 29 was closed and the supply of the R coating liquid to the intermediate tank 30 was stopped.

Each time the R coating liquid is discharged from the inkjet head 100 ten times, the valve 29 is closed and the valve 56 is closed. Then, the valve 58 and the valve 64 are opened almost simultaneously. Closed almost simultaneously. By this operation, it was observed that the R coating liquid containing fine bubbles first flows in the pipe 62 and only the R coating liquid flows finally. Thereafter, the valve 56 is opened and then the valve 29 is opened to supply the intermediate tank 30 with the R coating liquid. When the full sensor 42 detects the lower limit position of the resin film 34, the valve 29 is closed. The supply of the R coating liquid to the intermediate tank 30 was stopped. Thereafter, in the same manner, discharge of the R coating liquid from the inkjet head 100, replenishment of the R coating liquid to the intermediate tank 30, and discharge of the bubbles and staying coating once every 10 discharges of the R coating liquid from the inkjet head 100 The liquid was repeatedly discharged.

(Example 2)
Using the coating liquid supply apparatus 1 of Example 1 and the inkjet head 100, a color filter was produced using the coating liquid supply method of Example 1 as it was. By the previous process, on a non-alkali glass substrate of 1100 × 1300mm and 0.7mm thickness, each pixel has a width of 100μm, a length of 300μm, a black matrix width of 20μm, and a liquid repellent surface. A grid-like black matrix substrate having the property was prepared.

  This substrate is sucked and held on the suction stage 80 as the substrate A in FIG. 1, and while the suction stage is moved at 50 mm / s, the R coating liquid is first ejected from the inkjet head 100, and 360 pl coating liquid is ejected per pixel. Thus, only the R pixel was formed on the entire surface. The volume of the coating solution for R applied to one substrate A was 4.3 ml.

  In addition, replenishment of the coating liquid to the intermediate tank 30 of the coating liquid supply apparatus 1 was performed every time coating was completed. The operation of discharging the bubbles and the staying coating liquid from the intermediate tank 30 was performed every time coating was completed 30 times. Subsequently, G pixels and B pixels were sequentially formed under the same conditions. After each color pixel formation is completed, pre-baking is performed at 100 degrees for 10 minutes. After all the R, G, and B color pixels are formed, baking is performed at 230 ° C. for 30 minutes, and finally, R, having a thickness of 2 μm, A color filter with G and B pixels could be obtained.

  Further, this color filter was superposed on the substrate on which the TFT array was formed, and heated at 160 ° C. for 90 minutes while being pressurized in an oven to cure the sealant. After liquid crystal injection into this cell, the liquid crystal injection port was sealed with an ultraviolet curable resin. Next, a polarizing plate was attached to the outside of the two glass substrates of the cell, and the obtained cell was modularized to complete a liquid crystal display device. The obtained liquid crystal display device had no defects due to bubbles or color particle defects due to pigment aggregation, and the chromaticity was uniform and satisfactory over the entire surface of the substrate.

  The present invention can be widely used in a coating apparatus using an ink jet.

FIG. 1 is a schematic front view of a coating liquid supply apparatus 1 according to the present invention. FIG. 2 is a schematic plan view of the intermediate tank 30. FIG. 3 is a schematic front sectional view showing a filling state of the coating liquid in the intermediate tank 30. FIG. 4 is a schematic front cross-sectional view illustrating another filling state of the coating liquid in the intermediate tank 30.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating liquid supply apparatus 10 Main tank 10N New main tank 12 Bag member 12N New bag member 14 Connection member 16 Tube 16N New tube 18 Main body 20 Piping 22 Pressure regulator 24 Pressure air source 26 Open / close valve 28 Piping 29 Valve 30 Intermediate tank 32 Main body 34 Resin film 38 Inlet pipe 39 Inlet 40 Outlet pipe 41 Outlet 42 Full sensor 44 Piping 45 Vacuum pressure regulator 46 Holding member 48 Vacuum pump 50 Manifold 52 Upper end 54 Space 56 Valve 58 Valve 60 Discharge pipe 62 Piping 64 Valve 66 Drainage 68 Drain tank 70 Outlet 72 Coating liquid 74 Pressure regulator 76 Piping 78 Pressure air source 80 Adsorption stage 82 Guide 84 Rail 90 Bubble 92 Wall 94 Air reservoir 100 Inkjet head A Substrate Z Gravity direction (vertical direction)

Claims (6)

An inkjet head for discharging a coating liquid;
A coating liquid tank filled with the coating liquid;
An intermediate tank that is intermediate between the coating liquid tank and the inkjet head and that can be filled with the coating liquid and temporarily stored at a constant volume;
A coating liquid supply device for an ink jet head having a valve for transferring / stopping a coating liquid from a coating liquid tank to an intermediate tank,
The intermediate tank is
An inlet through which the coating liquid from the coating liquid tank flows,
An outlet through which the coating liquid flows out to the inkjet head;
A surface flexible film arranged so that its position can be changed in a substantially gravitational direction according to the volume of coating solution to be stored;
A coating liquid discharge port disposed above the inlet and outlet in the direction of gravity;
An open / close valve for controlling discharge / stop of the coating liquid from the coating liquid discharge port;
A chamber for depressurizing / pressurizing the surface flexible membrane;
A coating liquid supply apparatus for an inkjet head, comprising: 2. The coating liquid supply apparatus for an ink jet head according to claim 1, wherein the surface flexible film of the intermediate tank is disposed below the coating liquid in the gravity direction. 3. The coating liquid supply apparatus for an ink jet head according to claim 1, further comprising switching means for switching between pressure reduction / pressurization applied to the chamber of the intermediate tank. A method of supplying a coating liquid from an application liquid tank to an inkjet head through an intermediate tank having a surface flexible film on the lower side in the gravity direction,
Injecting the coating liquid into the intermediate tank from an inlet;
Discharging air bubbles and / or the coating liquid in the intermediate tank from the outlet in the gravity direction above the inlet and outlet of the intermediate tank;
A method for supplying a coating liquid to an inkjet head, comprising a step of supplying the coating liquid from an outlet of the intermediate tank to the inkjet head in a state where a negative pressure is applied to the intermediate tank. 5. The method of supplying a coating liquid for an ink jet head according to claim 4, wherein the step of discharging the coating liquid is a step of pressurizing the surface flexible film of the intermediate tank from the atmosphere side. A method for producing a color filter, comprising producing a color filter using the coating liquid supply method for an inkjet head according to claim 4.