JP4872294B2 - Ink jet head for ink containing fine particles - Google Patents

Description

  The present invention relates to an ink jet head for fine particle containing ink used in an ink jet apparatus for coating fine particle containing ink, and more particularly to an ink jet head for fine particle containing ink which is not easily blocked by fine particles.

  In a liquid crystal display device, a color filter and a liquid crystal driving side substrate are opposed to each other, a liquid crystal compound is sealed between them to form a thin liquid crystal layer, and the liquid crystal alignment in the liquid crystal layer is electrically controlled by the liquid crystal driving side substrate. Then, display is performed by selectively changing the amount of transmitted light or reflected light of the color filter.

  Such a liquid crystal display device has various driving methods such as a static driving method, a simple matrix method, and an active matrix method. Recently, an active matrix method or a simple matrix method is used as a flat display for a personal computer or a portable information terminal. Color liquid crystal display devices using liquid crystal panels are rapidly spreading.

  FIG. 2 shows an example of an active matrix liquid crystal display panel. In the liquid crystal display device 101, the color filter 21 and the TFT array substrate 22 which is a liquid crystal driving side substrate are opposed to each other, and a gap portion 23 of about 1 to 10 μm is provided. Is sealed with a sealing material 24 (for example, Patent Document 1). The color filter 21 has a light shielding part 26 formed in a predetermined pattern on the base material 25 to shield the boundary between the colored layers 27, and a plurality of colors (usually red (R) and green (G). , Three primary colors of blue (B)), a colored layer 27 arranged in a predetermined order, an overcoat layer 28, and a transparent electrode film 29 are stacked in this order from the side close to the transparent substrate.

  On the other hand, the TFT array substrate 22 has a structure in which TFT elements are arranged on a transparent substrate and a transparent electrode film is provided (not shown). An alignment film 30 is provided on the inner surface side of the color filter 21 and the TFT array substrate 22 facing the color filter 21. A color image is obtained by controlling the light transmittance of the liquid crystal layer behind the colored layer.

  Here, the thickness of the gap 23, that is, the cell gap (gap distance between the color filter and the liquid crystal drive side substrate) is the thickness of the liquid crystal layer itself, and prevents display unevenness such as color unevenness and contrast unevenness, and uniform display. In order to provide a color liquid crystal display device with good display performance such as high-speed response, high contrast ratio, and wide viewing angle, it is necessary to maintain the cell gap constant and uniform.

  Regarding the uniformization of the cell gap, Patent Document 2 discloses a method of forming a spacer composed of beads and an adhesive by an inkjet method using a bead spacer forming agent including beads and an adhesive. Such a spacer composed of beads and an adhesive is useful in that a uniform cell gap can be realized with high accuracy. However, the method of forming such a spacer by the ink jet method is useful in that the spacer can be formed at an arbitrary place, but the ink flow path in the ink jet head used in the ink jet method is blocked with beads. Therefore, there is a problem that the bead spacer forming agent cannot be discharged stably for a long time.

JP-A-8-194216 JP 2001-83524 A

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide an ink jet head for fine particle-containing ink that can stably discharge fine particle-containing ink for a long time.

In order to solve the above-described problems, the present invention is formed by connecting an ink supply channel for supplying fine particle-containing ink to the inside of an inkjet head, and the ink supply channel, and the inside of the inkjet head through the ink supply channel. A manifold portion that temporarily stores the supplied fine particle-containing ink, an ink discharge port that discharges the fine particle-containing ink, and the manifold portion and the ink discharge port are formed to be connected to each other and stored in the manifold portion. An ink discharge flow path for passing the fine particle-containing ink to the ink discharge port, wherein the ink supply flow path inner peripheral surface, the manifold portion inner peripheral surface, the ink discharge flow road inner peripheral surface, and characterized in that all of the ink discharge ports circumferential surface is lyophobic treatment An inkjet head for the fine particle-containing ink.

According to the present invention, the ink supply channel inner peripheral surface, the manifold portion inner peripheral surface, the ink discharge channel inner peripheral surface, and the ink, which are in contact with the ink jet head and the fine particle-containing ink in the ink jet head. Since all of the inner peripheral surface of the discharge port is subjected to the liquid repellency treatment, the fine particles contained in the fine particle-containing ink can be prevented from adhering to these parts. Thereby, according to the inkjet head for fine particle-containing ink of the present invention, the fine particle-containing ink can be stably ejected for a long time.

  In the present invention, it is preferable that the inner peripheral surface of the ink contact portion where the fine particle-containing ink comes into contact is subjected to a liquid repellency treatment. Since all the inner peripheral surface of the ink contact portion is subjected to the liquid repellency treatment, it is possible to prevent fine particles from adhering to all portions where the ink jet head and the fine particle-containing ink are in contact with each other. This is because fine particles can be prevented from adhering to portions other than the inner peripheral surface, the inner peripheral surface of the manifold section, the inner peripheral surface of the ink discharge channel, and the inner peripheral surface of the ink discharge port.

  In the present invention, the lyophobic treatment is preferably a fluororesin coating. This is because the fluororesin coating allows a water repellent treatment to be easily performed and also realizes excellent liquid repellency.

  Furthermore, in the present invention, it is preferable that the inner peripheral surface of the ink contact portion with which the fine particle-containing ink comes into contact is mirror-finished. This is because the ink contact portion is mirror-finished, so that the anchor effect can be suppressed, so that the inkjet head can be further prevented from being blocked by the fine particle-containing ink.

  According to the inkjet head for fine particle-containing ink of the present invention, there is an effect that the fine particle-containing ink can be ejected stably for a long time.

  The inkjet head for fine particle-containing ink of the present invention (hereinafter sometimes simply referred to as an inkjet head) is formed by being connected to an ink supply channel for supplying fine particle-containing ink into the inkjet head and the ink supply channel. A manifold part for temporarily storing the fine particle-containing ink supplied into the ink jet head through the ink supply channel, an ink discharge port for discharging the fine particle-containing ink, and the manifold part and the ink discharge port are connected to each other. And an ink discharge channel for passing the fine particle-containing ink stored in the manifold portion to the ink discharge port, the ink supply flow channel inner circumference A surface, an inner peripheral surface of the manifold part, an inner peripheral surface of the ink discharge channel, and At least one of the serial ink discharge ports peripheral surface and is characterized in that it is liquid-repelling treatment.

Next, the ink jet head of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of the ink jet head of the present invention. As shown in FIG. 1, the inkjet head 10 of the present invention includes an ink supply channel 1 that supplies fine particle-containing ink into the inkjet head 10, a manifold portion 2 that is formed in connection with the ink supply channel 1, and The ink discharge channel 3 formed so as to connect the manifold portion 2 and the ink discharge port 4 and the piezo element 6 formed in a part of the ink discharge channel 3 are provided. The inner peripheral surface of the discharge channel 3 is subjected to a liquid repellency treatment. Here, in this example, since the ink discharge channel 3 and the ink discharge port 4 are integrally formed, when the inner peripheral surface of the ink discharge channel 3 is subjected to lyophobic treatment, the ink discharge port The inner peripheral surface of 4 is also subjected to the liquid repellent treatment.
The fine particle-containing ink ejected using the inkjet head 10 of the present invention is first passed through the ink supply channel 1 and then temporarily stored in the manifold portion 2. Thereafter, the piezoelectric element 6 is deformed by applying an external voltage, so that the ink containing fine particles is pushed out toward the ink discharge port 4 through the ink discharge channel 3 and discharged from the ink discharge port 4. .
As illustrated in FIG. 1, the inkjet head 10 of the present invention may have an ink return channel 5 through which ink containing fine particles passes from the inside of the inkjet head to the outside of the inkjet head.

The method of discharging fine particle-containing ink by the ink jet method has an advantage that high-definition coating can be performed, but the fine particles adhere to the inner peripheral surface of the ink jet head in the ink jet head, and the flow path in the ink jet head with time There was a problem that was blocked.
According to the present invention, the ink supply flow path inner peripheral surface, the manifold portion inner peripheral surface, the ink discharge flow path inner peripheral surface, and the ink discharge, where the fine particle-containing ink and the ink jet head come into contact with each other in the ink jet head. Since at least one of the inner peripheral surfaces of the flow path is subjected to the liquid repellency treatment, the fine particles contained in the fine particle-containing ink can be prevented from adhering to the inner peripheral surfaces of these portions. Thus, the ink jet head of the present invention can suppress the ink flow path from being blocked by the fine particles, and can discharge the fine particle-containing ink stably for a long time.

  Hereinafter, the ink jet head for fine particle-containing ink of the present invention will be described in detail.

1. Liquid repellent treatment The ink jet head of the present invention includes an ink supply channel inner peripheral surface, a manifold portion, an ink discharge channel inner peripheral surface, and an ink discharge port inner peripheral surface (hereinafter referred to as “ At least one of which may be referred to as a “main ink wetted surface”). Accordingly, in the present invention, any of the main ink wetted surfaces may be subjected to a liquid repellency treatment, and a specific portion to be subjected to the liquid repellency treatment is appropriately selected according to the use of the inkjet head of the present invention. Just do it. In the ink jet head of the present invention, a single portion of the main ink contact surface may be subjected to a liquid repellent treatment, or a plurality of locations may be subjected to a liquid repellent treatment.

In the present invention, it is preferable that at least one of the inner peripheral surface of the ink discharge flow channel and the inner peripheral surface of the manifold portion is subjected to a liquid repellent treatment among the main ink contact surfaces. Furthermore, it is preferable that both the inner peripheral surface of the ink discharge channel and the inner peripheral surface of the manifold portion are subjected to a liquid repellency treatment.
Since the ink discharge flow path has a relatively small diameter, it tends to be clogged by adhering fine particle images to the inner peripheral surface. Therefore, it is possible to effectively prevent the ink jet head from being blocked due to the liquid repellent treatment on the inner peripheral surface of the ink discharge channel.
Further, since the manifold portion has a relatively large volume, the residence time of the fine particle-containing ink becomes long, so that the fine particles are likely to adhere. Therefore, it is possible to further prevent the inkjet head from being blocked by the liquid repellent treatment on the inner peripheral surface of the manifold portion.

  In the ink jet head of the present invention, it is preferable that all of the main ink contact surfaces are subjected to a liquid repellency treatment. This is because the blocking effect of the ink jet head according to the present invention can be exhibited most when all of the main ink wetted surfaces are subjected to the water repellent treatment.

  In addition, when the ink jet head of the present invention has other ink wet surfaces other than the main ink wet surfaces, the main ink wet surfaces and the other ink contact surfaces where the ink jet head and the fine particle-containing ink come into contact with each other. The ink wetted surface is preferably subjected to a liquid repellent treatment. Since the main ink wetted surface and other ink wetted surfaces are subjected to the liquid repellent treatment, the entire ink wetted surface of the ink jet head of the present invention is subjected to the liquid repellent treatment. It is because it can suppress more effectively. Examples of the other ink contact surface include an inner peripheral surface of an ink return flow path, which will be described later, and a surface where the piezo element and the fine particle-containing ink are in contact with each other.

The liquid repellency treatment used in the present invention is not particularly limited as long as it can prevent fine particles from adhering to the ink contact surface according to the type of fine particles used in the fine particle-containing ink. Moreover, the liquid repellent treatment used in the present invention may be only one type, or two or more types may be used. In the present invention, as an aspect in which two or more types of liquid repellency treatment are performed, for example, an aspect in which a different liquid repellency process is performed for each portion of the main ink contact surface can be given.
The liquid repellency treatment in the present invention is not limited to performing liquid repellency using a liquid repellent material for an ink jet head composed of an arbitrary material or a member thereof, but the ink jet head or the member itself. It is also included that the liquid is made of a liquid repellent material.

  Examples of the liquid repellency treatment used in the present invention include a method of coating a fluororesin on an ink jet head made of an arbitrary material or a member thereof, and a method of producing an ink jet head or a member thereof from a fluororesin. . In the present invention, any of these methods can be suitably used.

  The fluororesin is not particularly limited, and those generally used for fluororesin coating can be used. Examples of such a fluororesin include PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), ETFE (tetrafluoroethylene). Fluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), FAS (fluoroalkylsilane) and the like. In particular, in the present invention, it is preferable to use PTFE (polytetrafluoroethylene) as the fluororesin.

The method for coating the inkjet head of the present invention with a fluororesin coating is not particularly limited as long as the fluororesin coating can be applied to a desired site. As such a method, for example, in the stage before assembling the inkjet head of the present invention, the method of assembling the inkjet head after applying the fluororesin coating on the surface of the desired member, and after assembling the inkjet head, An example is a method in which a fluororesin coating composition containing a fluororesin is passed through an inkjet head.
In the former method, it is possible to obtain an ink jet head in which a part of the ink contact portion is coated with a fluororesin by coating only the surface of a desired member with a fluororesin. By applying the fluororesin coating to the ink jet head, it is possible to obtain an ink jet head in which the entire ink contact surface is coated with the fluororesin. Examples of the method of coating the surface of the member with a fluororesin include a method of immersing each member in a fluororesin coating composition containing the fluororesin.
On the other hand, the latter method cannot obtain an ink jet head in which a part of the ink wetted surface is coated with fluororesin, but an ink jet head in which the entire ink wetted surface is coated with fluororesin is easier than the former method. It has the advantage that it can be obtained.

  When a fluororesin coating is used as the lyophobic treatment, the film thickness of the fluororesin coating is not particularly limited as long as it is within a range in which adhesion of the fine particles can be prevented according to the type of the fluororesin. In the present invention, the film thickness of the fluororesin coating is preferably in the range of 1 nm to 10 μm, and more preferably in the range of 1 nm to 1 μm. If the film thickness of the fluororesin coating is thinner than the above range, the effect of preventing the adhesion of fine particles may be insufficient, and if it is thicker than the above range, the ink flow path in the inkjet head is narrowed, This is because the pressure loss becomes large and high-definition ejection may not be possible.

2. Inkjet Head The inkjet head of the present invention is formed by being connected to an ink supply channel for supplying fine particle-containing ink into the inkjet head and the ink supply channel, and is supplied into the inkjet head through the ink supply channel. A manifold portion that temporarily stores the fine particle-containing ink, an ink discharge port that discharges the fine particle-containing ink, and the manifold portion and an ink discharge port that discharges the fine particle-containing ink are connected to each other. And an ink discharge channel for passing the contained fine particle-containing ink to the ink discharge port.

  Specific embodiments of the ink supply channel, the manifold section, and the ink discharge channel in the inkjet head of the present invention are not particularly limited, and the use of the inkjet head of the present invention and the inkjet head of the present invention are used. It may be arbitrarily determined according to the composition of the fine particle-containing ink discharged.

  The ink jet head of the present invention may have other configurations other than the ink supply channel, the manifold unit, the ink discharge channel, and the ink discharge port. In the present invention, as other configurations described above, usually, an ink return channel for passing fine particle-containing ink from the inside of the inkjet head to the outside of the inkjet head, and the fine particle-containing ink are ejected from the ink ejection port through the ink ejection channel. A pressure device is used.

  The ink return flow path has a function of constantly maintaining a balance between the amount of the fine particle-containing ink supplied into the inkjet head and the amount of the fine particle-containing ink discharged to the outside of the inkjet head. Since the discharge amount can be prevented from fluctuating, it is preferably used in the present invention. The mode of such an ink return channel is not particularly limited as long as it is a mode in which fine particle-containing ink can be passed from the manifold section to the outside of the inkjet head.

  The pressurizing device is not particularly limited as long as the pressurization necessary for ejecting a desired amount of fine particle-containing ink from the ink ejection port can be performed. In the present invention, a device in which a piezo element is formed in a part of the ink discharge channel is preferably used as such a pressure device.

  The piezo element is not particularly limited as long as it has a function of deforming with application of an external voltage, reducing the volume of the ink discharge flow path, and extruding the fine particle-containing ink. In the present invention, a piezoelectric element generally used for an ink jet head can be used.

  The ink jet head of the present invention may have one ink discharge port or a plurality of ink discharge ports. In the present invention, it is preferable to have a plurality of ink discharge ports. This is because by having a plurality of ink discharge ports, it is possible to simultaneously discharge fine particle-containing ink to a plurality of locations.

  The minimum diameter of the ink flow path through which the fine particle-containing ink in the inkjet head of the present invention flows is not particularly limited as long as it is larger than the particle size of the fine particles contained in the fine particle-containing ink discharged using the inkjet head of the present invention. In particular, in the present invention, the minimum aperture is preferably 2.5 times or more than the particle size of the fine particles, and more preferably 3 times or more. More specifically, the range of 1 μm to 100 μm is preferable, and the range of 15 μm to 40 μm is particularly preferable.

  Further, in the ink jet head of the present invention, it is preferable that the inner peripheral surface of the ink contact portion where the fine particle-containing ink comes into contact is mirror-finished. This is because the ink contact portion is mirror-finished, so that the anchor effect can be suppressed, so that the inkjet head can be further prevented from being blocked by the fine particle-containing ink. Further, the mirror surface treatment may be performed on only a part of the ink contact part or on the entire surface.

3. Use The ink jet head of the present invention is used in an ink jet apparatus for coating fine particle-containing ink containing fine particles in an arbitrary solvent. Among these, the ink jet head of the present invention is suitably used for an ink jet apparatus that ejects fine particle-containing ink containing fine particles having a particle diameter of 0.1 μm to 10 μm, particularly 1 μm to 8 μm. .

  The ink jet head of the present invention is preferably used for an ink jet device for forming a bead spacer of a color filter used for a liquid crystal display device. When used in such applications, beads that are generally used as bead spacers for color filters are used as the fine particles contained in the fine particle-containing ink.

Examples of the beads include porous, non-porous and hollow bodies of inorganic compounds such as glass, silica and metal oxides (MgO, Al ₂ O ₃ ), polystyrene, polyethylene, polypropylene, polyester, polyacryl, Plastics such as nylon and silicone resin can be used. In addition, the surface of such a bead may be subjected to a surface treatment in order to improve the adhesiveness with the resin contained in the bead composition layer.

  The shape of the beads is preferably spherical. Further, the particle size of the beads is preferably about 1.0 μm to 8.0 μm, and more preferably about 2.5 μm to 5.5 μm.

  Further, the fine particle-containing ink used in the ink jet apparatus for fine particle-containing ink of the present invention may contain a resin. Examples of such resins include acrylic resins, epoxy resins, and melamine resins.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described more specifically by showing examples.

  A piezoelectric element substrate in which a flow path was formed was obtained by bonding a substrate on which piezoelectric elements are arranged and stainless steel processed so that the piezoelectric element portion becomes an opening with an epoxy resin adhesive. Except for the wetted part where the piezo element substrate and the fine particle-containing ink come in contact with each other, mask with a polyimide tape, soak it in a hydrolyzed solution of fluoroalkylsilane, lift it at room temperature, and then peel off the masking tape. Only the liquid part was subjected to a liquid repellency treatment. The fluororesin (tetrafluoroethylene resin) in which the liquid-repellent piezo element substrate, the ink supply flow path, the ink return flow path, the manifold portion, the ink discharge flow path, and the ink discharge port are formed is made of epoxy resin. The ink jet head was bonded with an adhesive to produce a liquid repellent inside of the flow path.

  When the produced ink-jet head was used to make a fine particle-containing ink having the following composition, the ink-jet head was not blocked by the adhesion of fine particles.

<Composition of fine particle-containing ink>
Beads: Sekisui Chemical Micropearl particle size 4 μm 1.0% by mass
Thermosetting resin: acrylic resin (glycidyl methacrylate) 20.0% by mass
Solvent: 79.0% by mass of butyl carbitol acetate

It is the schematic which shows an example of the inkjet head of this invention. It is the schematic for demonstrating the conventional color filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ink supply flow path 2 ... Manifold part 3 ... Ink discharge flow path 4 ... Ink discharge port 5 ... Ink return flow path 6 ... Piezo element

Claims (4)

An ink supply channel for supplying fine particle-containing ink to the inside of the inkjet head and a connection with the ink supply channel are formed, and the fine particle-containing ink supplied into the inkjet head through the ink supply channel is temporarily stored. A manifold portion, an ink discharge port for discharging fine particle-containing ink, and the fine particle-containing ink contained in the manifold portion formed to connect the manifold portion and the ink discharge port. An ink discharge channel for passing the liquid, and an ink jet head for fine particle-containing ink,
The fine particle-containing ink , wherein all of the inner peripheral surface of the ink supply channel, the inner peripheral surface of the manifold portion, the inner peripheral surface of the ink discharge channel, and the inner peripheral surface of the ink discharge port are liquid-repellent. Inkjet head. 2. The ink jet head for fine particle-containing ink according to claim 1, wherein the inner peripheral surface of the ink contact portion where the fine particle-containing ink comes into contact is all subjected to a liquid repellency treatment. The inkjet head for fine particle-containing ink according to claim 1, wherein the liquid repellency treatment is a fluororesin coating. The ink jet head for fine particle-containing ink according to any one of claims 1 to 3, wherein the inner peripheral surface of the ink contact portion where the fine particle-containing ink comes into contact is mirror-finished. .

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