JP2001091952A - Ink supply device and ink container used for the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink supply device with which stable ink supply is made possible in ink supply when alignment layer formation by an ink jet method is carried out and an ink container used for the same. SOLUTION: The device for supplying alignment layer ink (a) to an ink jet heat 7 when the alignment layer formation of an liquid crystal display element consisting of two sheets of patterned transparent substrate is carried out by the ink jet method has an ink container 21 in which the alignment layer ink (a) is sealed together with inert gas, such as nitrogen or helium, not absorbed by the alignment layer ink. The device subjects the alignment layer ink (a) sealed into the ink container 21 to a deaeration treatment before sealing the ink into the ink container 21. A reservoir tank 28 which maintains the liquid level of the alignment layer ink (a) constant at all times is interposed between the ink container 21 and the ink jet head 7. The ink container 21 comprises a case-like outer container 22 and a bag-like inner container 23 stored in the outer container 22 and the alignment layer ink (a) is sealed into the inner container 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink supply device,
More specifically, the present invention relates to an alignment film ink supply device and an ink container used for forming an alignment film of a liquid crystal display element including two patterned transparent substrates by an inkjet method.

[0002]

2. Description of the Related Art In a method of manufacturing a liquid crystal display device comprising two patterned transparent substrates, a flexographic printing method is generally used as a method for forming an alignment film on a transparent substrate.

In the flexographic printing method, as shown in FIG. 3, an alignment film ink a is dropped from a supply nozzle 1 onto an anilox roller 2, and the alignment film ink dropped by a doctor roller 3 close to the anilox roller 2. a is extended so as to have a uniform thickness to form an ink thin film b on the anilox roller 1, the ink thin film b is provided on the plate cylinder 4, transferred onto the relief plate 5, and The alignment film c is transferred to the surface to form an alignment film c.

Usually, polyimide-based inks are often used as the alignment film ink.

The alignment film ink used in the conventional flexographic printing method is usually sold in a glass bottle or a resin container such as polyethylene. In this case, the alignment film ink is not particularly degassed.

In the flexographic printing apparatus, when the alignment film ink a is supplied to the apparatus main body, as shown in FIG. Pressurized tank 1 housed inside
Of the pressurized tank 10 by pressurizing the inside of the pressurized tank 10 with nitrogen gas by injecting nitrogen gas into the inside of the ink tank 9 through the supply tube 12 to the apparatus main body. Alternatively, as shown in FIG. 5B, the orientation film ink a is transferred to the dedicated container 13 and stored therein, and nitrogen gas is injected into the dedicated container 13 through the nitrogen gas line pipe 11. Thus, either of the methods of pressurizing the interior of the dedicated container 13 with nitrogen and supplying the alignment film ink a to the apparatus main body via the supply tube 12 is used. Incidentally, since the alignment film ink a has a property of being cured when dried, it is more likely that FIG.
An ink supply method in which the ink is used up and the entire container is replaced as in the method shown in (a) is more preferable in terms of quality.

[0007]

By the way, in the case of the flexographic printing method, although the patterning of the alignment film can be easily formed and the productivity is high, there are the following problems.

[0008] Repeat failures occur frequently due to dust adhering to the relief printing plate (a factor for lowering the yield).

[0009] The usage fee of the alignment film ink is large.

It is difficult to return after stopping the apparatus.

Therefore, in recent years, as new systems, for example, Japanese Patent Application Laid-Open No. 3-249623 and Japanese Patent Application Laid-Open No. 7-92467.
A method for forming an alignment film by ink jet disclosed in Japanese Patent Application Laid-Open No. H10-209, etc., a so-called ink jet method has been proposed.

[0012] As shown in FIG.
While relatively moving the transparent substrate 6 and the inkjet head 7 of the inkjet printer, the alignment film ink a is ejected from the ink ejection holes 8 of the inkjet head 7 onto the surface of the transparent substrate 6 to form the alignment film c.

The ink-jet method is a method that can solve the above-mentioned problem in the flexographic printing method. However, there are many problems to realize this method, but there are the following problems with respect to ink supply.

The quality of the alignment film ink is maintained (precipitation of polymer, etc.), and bubbles are prevented from being mixed into the alignment film ink so that abnormal ink ejection does not occur.

In the case where the alignment film pattern is filled with an ink jet printer, it is possible to prevent the ink level from fluctuating due to the movement of the head, thereby preventing the ink ejection from becoming unstable.

Accordingly, the present invention provides an ink supply device capable of overcoming the above-mentioned problems in an ink supply device in which an alignment film of a liquid crystal display element comprising two patterned transparent substrates is formed by an inkjet method. It is intended to provide an ink container to be used.

[0017]

In order to achieve the above object, the present invention provides a method for forming an alignment film of a liquid crystal display device comprising two patterned transparent substrates by an inkjet method. A device for supplying to a head, comprising an ink container in which the alignment film ink is sealed together with an inert gas such as nitrogen or helium which is not absorbed by the alignment film ink.

Further, the alignment film ink sealed in the ink container is deaerated before being sealed in the ink container.

Further, the ink container comprises a case-shaped outer container and a bag-shaped inner container housed inside the outer container, and the alignment film ink is sealed inside the inner container. It is characterized by the following. The outer case is made of a material having such a rigidity that the shape thereof can be maintained during handling such as transportation, storage and use, and a strength that is not easily damaged.
Further, the inner container is formed of a flexible material that can be deformed in accordance with the filling pressure and the filling amount of the inside filling material. Desirably, it is formed of a material having resistance to a solvent or the like contained in the alignment film ink.

Further, a reserve tank is provided between the ink container and the ink jet head to keep the liquid level of the alignment film ink constant.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to FIGS.

FIG. 1 shows an ink container 21 used when the alignment film ink a is supplied to an ink jet head in the present invention. The ink container 21 includes a case-shaped outer container 22,
A bag-shaped inner container 2 housed inside the outer container 22
And 3. The outer container 22 is made of a material having a certain rigidity and strength, such as a plastic plate,
On the side surface, an elongated through-hole 24 for confirming the amount of ink inside and preventing pressure reduction is formed. The inner container 23
It has flexibility such as plastic thin sheet, and
Manufactured from materials with excellent solvent resistance. The inner container 23
A stopper 25 such as rubber or resin having a certain thickness is fitted into the distal end portion 23a to be completely sealed, and the distal end portion 23a is fixed to the fixing hole 22a formed on the bottom surface of the outer container 22.
And fixed to the outer container 22. Inner container 23
In addition to enclosing the alignment film ink a inside, an inert gas such as nitrogen or helium that is not absorbed by the alignment film ink a is also enclosed. Alignment film ink a sealed in inner container 23
Is preliminarily deaerated by ultrasonic waves or the like.

When the alignment film ink a is supplied to the ink jet head using the ink container 21, the tip of a tube 26 connected to the apparatus main body is connected to a plug 25 fitted to a front end 23 a of the inner container 23. When the attached hollow needle 27 is pierced, the alignment film ink a sealed in the inner container 23 is supplied from the needle 27 to the inkjet head via the tube 26.

According to the present invention, the orientation film ink a is sealed in the ink container 21 together with an inert gas such as nitrogen or helium which is not absorbed by the orientation film ink a, so that the inert gas causes the orientation film ink a to absorb moisture. Precipitation of the polymer can be prevented, and air bubbles can be prevented from being mixed into the alignment film ink a. Therefore, there is no need to worry about abnormal ejection of the alignment film ink a due to polymer separation and mixing of air bubbles. A squirt can be performed. Moreover, since the alignment film ink a enclosed in the ink container 21 is degassed in advance to completely remove bubbles in the alignment film ink a, the alignment film ink a can be ejected in a more stable state. It is possible.

In the above description, when the alignment film ink a is supplied to the ink jet head, the tube 25 connected to the ink jet head is connected to the plug 25 fitted to the tip end 23a of the inner container 23 of the ink container 21. Although the hollow needle 27 attached to the tip was pierced, a tube whose tip was sealed in advance was plugged and fixed to the plug 25, and the tube was sealed when the alignment film ink a was supplied to the apparatus main body. The portion may be removed and connected to the tube 26 connected to the inkjet head using a joint or the like.

Although the tip opening 23a of the inner container 23 of the ink container 21 may be directed upward, it is preferable that it be directed downward in consideration of using up the alignment film ink a to the end.

FIG. 2 shows an embodiment for preventing ejection instability due to fluctuations in the liquid level of the alignment film ink a. The liquid of the alignment film ink a is placed between the ink container 21 and the ink jet head. A reserve tank 28 that keeps the surface level constant is interposed. The reserve tank 28 is formed in a mortar shape in order to prevent scum of the alignment film ink a (for example, scum obtained by solidification of the polymer) from being deposited on the wall surface, and to improve the flow of the alignment film ink a on the inner surface. Is subjected to a water-repellent treatment with Teflon or the like. The reserve tank 28 has an upper lid 29 fitted in the upper end opening and the upper end opening is closed, and the ink supply tube 30 connected to the ink container 21 is fixed to the upper lid 29 so as to pass therethrough. The reserve tank 28 is provided with an ink lower limit sensor 31 and an ink upper limit sensor 32 at a start end 30a inserted into the inside of the ink supply tube 30 from the penetrating portion of the upper lid 29. When the small pump 33 installed in the middle of the supply tube 30 is driven and the ink upper limit sensor 32 operates, the small pump 3
3 is stopped. The reserve tank 28 includes an upper lid 29.
And an inert gas such as nitrogen or helium which is not absorbed by the alignment film ink a through the inert gas line pipe 34 is injected from the inert gas cylinder 35 through the inert gas line pipe 34 by the pressure controller 36. Is done.
In FIG. 2, reference numeral 37 denotes an ink supply tube provided for supplying the alignment film ink a from the reserve tank 28 to the inkjet head, and 38 supplies or supplies the alignment film ink a from the reserve tank 28 to the inkjet head. Is a metal mesh filter provided for removing scum of the alignment film ink a, and 40 is a valve for preventing air bubbles from entering the ink supply tube 38 from the ink supply tube 30. The reference numeral 41 designates a pan, 41 is a cleaning spray nozzle provided for cleaning the inside of the reserve tank 27 with a solvent when the apparatus is stopped, and 42 is a pressure control valve provided for controlling the pressure inside the reserve tank 27.

According to this embodiment, the reserve tank 2
The ink lower limit sensor 31 or the ink upper limit sensor 32 is operated by the fluctuation of the liquid level of the alignment film ink a contained in the inside 7, and the liquid level of the alignment film ink a in the reserve tank 27 is kept constant by the small pump 33. keep. That is, when the alignment film ink a is supplied from the reserve tank 27 to the ink jet head and the liquid level of the alignment film ink a in the reserve tank 27 falls to the lower limit position, the ink lower limit sensor 31 is activated and the small pump 33 is driven. Thus, the alignment film ink a is supplied from the ink container 21 to the reserve tank 27 via the ink supply tube 30. Then, the alignment film ink a is supplied from the ink container 21 to the reserve tank 27, and
When the liquid level of the alignment film ink a rises to the upper limit position, the ink upper limit sensor 32 operates and the small pump 3
3 is stopped, and the supply of the alignment film ink a from the ink container 21 to the reserve tank 27 is stopped. As described above, when the liquid level of the alignment film ink a in the reserve tank 27 decreases, the reserve tank 27 is removed from the ink container 21.
When the liquid level of the alignment film ink a in the reserve tank 27 rises, the ink container 21
Since the supply of the alignment film ink a to the reserve tank 27 is stopped, the liquid level of the alignment film ink a in the reserve tank 27 can be kept constant. Therefore, by interposing a reserve tank 28 for keeping the liquid level of the alignment film ink a constant between the ink container 21 and the ink jet head, the alignment film ink a due to the fluctuation of the liquid level of the alignment film ink a is provided. No more worries about eruption
Stable ejection of the alignment film ink a can be performed.

Further, according to this embodiment, after the orientation film ink a is supplied from the ink container 21 to the reserve tank 28, the inert gas line 35 is supplied from the inert gas cylinder 35 by the pressure controller 36 into the reserve tank 28. By injecting an inert gas, such as nitrogen or helium, which is not absorbed into the alignment film ink a through the reservoir, the inside of the reserve tank 28 is filled with the inert gas, and the alignment film ink causing abnormal ejection of the alignment film ink a It is possible to prevent air bubbles from entering into a.

In this embodiment, the ink container 21 and the reserve tank 28 may be adjacent to or separated from each other. However, when moving simultaneously with the ink jet head, only the reserve tank 28 is moved. It is desirable that the ink container 21 be fixed. When the ink jet head and the reserve tank 28 are simultaneously moved, it is desirable to provide a mechanism for absorbing vibration such as a pendulum sensor in order to suppress the swing of the alignment film ink a in the reserve tank 28.

[0031]

As described above, according to the present invention, the alignment film ink is sealed in the ink container together with an inert gas such as nitrogen or helium which is not absorbed by the alignment film ink, so that the quality of the alignment film ink is maintained. (Prevention of polymer precipitation due to moisture absorption), and prevention of bubbles from being mixed into the alignment film ink, stable supply of the alignment film ink, and good ejection of the alignment film ink.

Further, since a reserve tank for keeping the liquid level of the alignment film ink constant is interposed between the ink container and the ink jet head, the abnormal ejection of the alignment film ink due to the fluctuation of the liquid surface level of the alignment film ink. This eliminates the concern of the above, and enables more stable supply of the alignment film ink, thereby enabling better ejection of the alignment film ink.

[Brief description of the drawings]

FIG. 1 is a drawing showing an ink container used when supplying an alignment film ink to an inkjet head in the present invention.

FIG. 2 is a schematic configuration diagram showing an embodiment for preventing ejection instability due to fluctuations in the liquid level of an alignment film ink.

FIG. 3 is a drawing showing formation of an alignment film by flexographic printing.

FIG. 4 is a view showing formation of an alignment film by an inkjet method.

5A and 5B show an ink supply unit for forming an alignment film by flexographic printing, wherein FIG. 5A shows a method in which a container containing the alignment film ink is stored in a pressurized tank as it is, and FIG. It is a method of moving and changing and housing.

[Explanation of symbols]

 a Orientation film ink 21 Ink container 22 Outer container 23 Inner container 23a Tip mouth 25 Stopper 27 Hollow needle 28 Reserve tank 31 Ink lower limit sensor 32 Ink upper limit sensor 33 Small pump

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideyuki Nakatani 5 Asahioka, Kannabe-cho, Shenzhen-gun, Hiroshima Prefecture F-term (reference) 2C056 FB01 FB08 2H090 HB08Y HC05 HC18

Claims (5)

[Claims] An apparatus for supplying an alignment film ink to an inkjet head when forming an alignment film of a liquid crystal display element comprising two patterned transparent substrates by an inkjet method, comprising: An ink supply device comprising an ink container sealed with an inert gas not absorbed by an alignment film ink such as nitrogen or helium. 2. The ink supply device according to claim 1, wherein the alignment film ink sealed in the ink container is degassed before being sealed in the ink container. 3. The ink container includes a case-shaped outer container and a bag-shaped inner container housed inside the outer container, and the alignment film ink is sealed inside the inner container. 3. The ink supply device according to claim 1, wherein: 4. A reserve tank is provided between the ink container and the ink jet head, the reserve tank keeping the liquid level of the alignment film ink constant at all times.
4. The ink supply device according to 2 or 3. 5. An ink container for use in an ink supply device according to claim 1, wherein the outer container has a case shape and a bag-shaped inner container housed inside the outer container. An ink container comprising: an alignment film ink sealed inside the inner container.