JP2011206628A - Method of eliminating static from inkjet head, apparatus of eliminating static, inkjet head apparatus, and method of producing color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of eliminating static from an inkjet head having an ejection face not allowing an ink component to stick to the inside and the periphery of ejection ports disposed thereon even if an ink of high dispersibility containing fine particles of a pigment is ejected from a nozzle for a period of a few months, for preventing the fine particles of a pigment from sticking thereto due to the charging of the protective layers and the liquid repellent layers formed on the surfaces of the ejection ports and of the outlet faces thereof; an apparatus of eliminating static; an inkjet head apparatus; and a method of producing a color filter.SOLUTION: The method of eliminating static from an inkjet head is characterized by including radiating an ion beam from the needle point of a static-elimination electrode disposed on a lower position facing an ejection face, in the direction roughly parallel to the ejection face, and jetting an air stream upward by a means of jetting an air stream disposed on a lower position relative to the static-elimination electrode, to carry and blow the radiated ion beam onto the ejection face.

Description

  The present invention relates to an antistatic method for an ink jet head member having a fine discharge port for applying a fluid such as ink onto a substrate such as a glass substrate, a static eliminating method, and a static eliminating device. Further, the present invention relates to a color using an ink jet head. The present invention relates to a method for manufacturing a filter.

  The color liquid crystal display includes a color filter, a TFT array substrate, and the like. Among them, the color filter is formed by regularly arranging each pixel bordered by a grid-like black matrix on a glass substrate in three colors of RGB. This color filter is usually formed by forming a black photoresist material coating film on a glass substrate, processing the black coating film into a lattice pattern by photolithography, forming a coating film for each color on the entire surface, and then photolithography. Is manufactured from the step of leaving a predetermined color coating film between the lattices. In the RGB pixel formation by the photolithography method described above, many steps such as the formation of the entire surface coating film, exposure, and development are required for each color. In recent years, in order to simplify this, a technique for forming color pixels by supplying the R, G, and B coating liquids directly to the pixel portion formed by the black matrix lattice by the inkjet method has been industrially performed. It has been broken. This method of forming R, G, and B pixels using an ink jet head does not require steps such as exposure and development, and uses only the amount of coating liquid necessary for forming color pixels, thereby enabling a significant cost reduction in color filter manufacturing. To do.

  Ink jet heads usually have a large number of minute ejection openings, and intermittently drive the application liquid in the form of droplets from the ejection openings by operating intermittent drive means such as piezoelectric elements provided for each ejection opening. It is discharged.

  A protective layer and a liquid-repellent layer are formed on the surface of the discharge port and its outlet surface in order to protect the discharge port and improve the separation of the coating liquid to allow accurate discharge. For example, the plate including the discharge port may be formed of a resin containing fluorine, or a metal film may be formed on the surface of the nozzle plate, and a protective layer may be formed on the metal film.

  Patent Document 1 discloses a technique related to a covering structure for protecting the above-described discharge port. A schematic diagram is shown in FIG. A plurality of layers of the first discharge-resistant protective film 101, the second discharge-resistant protective film 102, and the third discharge-resistant protective film 103 are formed on the inner wall of the discharge port 21, and the inner wall of the discharge port 21 and the The liquid repellent film 100 is provided on the third discharge-resistant liquid protective film 103 on the discharge surface side excluding the surface opposite to the discharge surface. As a result, the droplets are smoothly ejected from the inner wall of the ejection port 21, and the droplets do not adhere to the surface of the liquid repellent film 100, so that the liquid runs out and is ejected with high accuracy. Further, durability against cleaning of the ejection surface is improved.

  However, according to the knowledge of the present inventors, when a highly finely dispersed ink is used as a coating liquid to produce a high-definition color filter, and the coating liquid is discharged from the nozzle for several months, it is protected. Even when a layer or a liquid repellent layer is provided, there is a problem that solidified ink as a coating liquid adheres to the inside of the discharge port or around the discharge port. From the discharge port to which the solidified material has adhered, normal discharge of the coating liquid is hindered, and the flight direction of the droplets cannot be determined. Therefore, there is a problem that the droplet cannot be landed on the target position of the base material, so that accurate color pixel formation of the color filter cannot be performed.

  According to the knowledge of the present inventors, the solidified product of the ink as the coating liquid adheres to the inside of the discharge port or around the discharge port. The discharge surface including the discharge port has an electrically insulating liquid repellent layer or a protective layer. It is thought that this is due to the fact that the static electricity is easily charged because it is composed of layers and the like, and the fine particles in the ink aggregate and deposit due to the influence of the static electricity. When using ink in which high-definition pigment is highly dispersed, it is considered that the influence of charging cannot be ignored.

  On the other hand, when a fluid is applied to a base material, static electricity may affect the formation of a coating film, which makes it difficult to form a coating film. ). In this technique, in FIG. 5, a plate-shaped static elimination electrode 115 is disposed facing the face plate 110 which is the lower surface of the nozzle discharge surface, and a voltage is applied between the conductive plate 124 in the nozzle 108, The potential of the face plate 110 is made sufficiently low. The shape of the static elimination electrode 115 is a plate-like shape. The voltage between the non-contact static elimination electrode 115 and the conductive plate 124 is regarded as a capacitor, and the voltage applied between the static elimination electrode 115 and the conductive plate 124 is charged to the face plate 110. The voltage of the polarity is opposite to that of the polarity, and the potential of the face plate 110 is controlled to a desired potential by electrostatic induction. However, according to the knowledge of the present inventors, in the static elimination utilizing the above-described electrostatic induction, the potential can be controlled when an electric field is applied from the outside. The existing electrostatic charge was not sufficiently neutralized, and the electrostatic charge remained on the face plate 110. According to the knowledge of the present inventors, this does not neutralize the positive charge and the negative charge by irradiating the reverse charge ions generated by corona discharge or the like to the electrostatic charge. This is because the adjustment is merely performed by applying a reverse polarity potential so as to be in the vicinity of zero. The charge state of the face plate 110 to be neutralized has a charge amount distribution. However, the technique of Patent Document 2 does not have a technical idea of performing control according to the charge amount distribution.

  As described above, when ink with high dispersibility including pigment fine particles is ejected for several months, the ink component adheres to the inside of the ejection port 21 or the liquid repellent layer 100 of the ejection port due to the influence of static electricity, and normal. In some cases, ejection was not possible. That is, according to the knowledge of the present inventors, the conventional liquid repellent layer cannot completely prevent the foreign matter from adhering to the lower surface of the nozzle of the inkjet head. According to the knowledge of the present inventors, this cause is due to the local distribution of the electrostatic charge on the discharge surface including the discharge port, and the charge prevention and charge removal on the nozzle discharge surface of the inkjet head have not been sufficient.

JP 2009-184176 A JP-A-63-15754

  The object of the present invention is to provide a protective surface that prevents ink components from sticking to the inside of the discharge port or around the discharge port even when highly dispersible ink containing fine pigment particles is discharged from the nozzle for several months. An object of the present invention is to provide an ink jet head static elimination method, a static elimination device, an inkjet head device, and a color filter manufacturing method that prevent adhesion of pigment fine particles caused by charging of a layer or a liquid repellent layer.

In order to achieve the above object, the present invention adopts the following configuration. That is,
According to the present invention, there is provided a discharge method for an inkjet head having a discharge port for discharging a coating liquid and a discharge surface including the discharge port, the needle of the discharge electrode provided at a lower position facing the discharge surface. Ions are radiated from the tip in a direction substantially parallel to the ejection surface, and the irradiated ions are jetted upward by an airflow ejecting means provided at a position below the static elimination electrode. There is provided a method of neutralizing an ink jet head that neutralizes the discharge surface by spraying the ions onto the discharge surface.

  According to another aspect of the present invention, there is provided an apparatus for neutralizing an inkjet head having an ejection port for ejecting a coating liquid and an ejection surface including the ejection port, the inkjet being moved by a moving means A discharge electrode needle that performs charge removal on the discharge surface of the head, and the tip of the discharge electrode needle has the discharge direction of the inkjet head in which the extension direction of the tip of the discharge electrode needle is moved by the moving means; An air flow ejecting means that is arranged so as to be substantially parallel to the surface, and that blows ions generated at the tip of the static elimination electrode needle to the ejection surface of the ink jet head moved by the moving means by an air flow. A neutralizing device for an ink jet head is provided.

  Further, according to a preferred embodiment of the present invention, the static elimination electrode needle has a shield electrode having an opening surrounding the static elimination electrode needle, and the shield electrode is a static elimination electrode in the extending direction of the tip of the static elimination electrode needle. There is provided a static eliminating device for an ink jet head which is arranged in front of a needle tip and which irradiates ions generated at a static elimination electrode needle tip from an opening of the front shield electrode.

  Moreover, according to the preferable form of this invention, the manufacturing method of the color filter which manufactures a color filter using the static elimination method of the said inkjet head or the static elimination apparatus of the said inkjet head is provided.

  According to the present invention, as described below, even when highly dispersible ink containing pigment fine particles is ejected from an inkjet nozzle for a long period of time, it is difficult for the ink component to adhere to the inside of the ejection port and around the ejection port. effective. Therefore, in the production of a color filter using an inkjet nozzle, it becomes possible to discharge a normal coating liquid, and it is possible to accurately form color pixels of a color filter by landing a droplet at a target position on a substrate. . Also, dust can be prevented from adhering due to electrostatic force by sufficiently removing electricity from the lower surface of the nozzle of the inkjet head.

It is the schematic which shows an example of the static elimination method of the inkjet head which concerns on this invention. It is the schematic plan view which looked at the discharge surface of the inkjet head which concerns on this invention from the lower side. FIG. 2 is an enlarged view of the vicinity of the static eliminator shown in FIG. It is the schematic which shows the conventional inkjet nozzle structure. It is the schematic which shows the static elimination method of the face plate of the conventional inkjet nozzle. It is a schematic plan view which shows an example of the static elimination method of the inkjet head which concerns on this invention.

  Hereinafter, an example of the best embodiment of the present invention will be described with reference to the drawings, taking as an example the case of manufacturing a color filter using an inkjet. FIG. 1 is a schematic diagram illustrating an example of a method for neutralizing an ink jet head according to the present invention. FIG. 2 is a plan view of the ejection surface of the inkjet head as viewed from below, and FIG. 3 is an enlarged view of the vicinity of the neutralization device of FIG.

  Referring to FIG. 1, a high voltage for applying a high voltage to the inkjet head 10, the coating liquid supply devices 14, 15, and 16 for the respective colors, the static elimination device 26 of the present invention, and the static elimination electrode needle tip in the static elimination device 26. A power source 22 and a coating liquid removing device 17 are shown. As shown in FIG. 2, the inkjet head 10 has a resin plate 18 on the discharge surface 12, and a discharge port 20 is formed in the resin plate 18. A liquid repellent layer is formed on the resin plate 18 of the discharge surface 12 by coating. The resin plate 18 is preferably made of a liquid repellent resin such as fluororesin (for example, “Teflon” (registered trademark)), silicone, polyimide or the like.

  Discharge ports 21 are formed in a number of discharge ports 20 that discharge the coating liquid, and the discharge ports 21 are arranged in a staggered pattern at a predetermined pitch in the longitudinal direction of the inkjet head 10. The inkjet head 10 is connected to the coating liquid supply devices 14, 15, and 16 by pipes 13. The coating liquid supply devices 14, 15, and 16 correspond to three colors of RGB. Moreover, the coating liquid supply devices 14, 15, and 16 include a coating liquid storage unit (not shown) in which the coating liquid is stored. The inkjet head 10 is disposed on the inkjet support 23. Due to the ink jet support 23, the ink jet head 10 is arranged on the stage 24 at a predetermined interval. The inkjet head 10 and the coating liquid supply devices 14, 15, and 16 can be freely reciprocated in the coating direction, that is, the X direction and the Y direction by a moving device (not shown). Further, the inkjet head 10 can be moved up and down freely in the vertical direction (Z direction) by a moving device (not shown).

  Next, the method for neutralizing the ink jet head of the present invention will be described. The inkjet head 10 is cleaned by the coating liquid removing device 17 in order to remove the coating liquid remaining around the ejection surface 12 and the ejection port 21. At that time, the inkjet head 10 moves greatly from above the stage 24 in order to move to a predetermined position of the coating liquid removing device 17. First, as a preparatory operation, a movement command is issued from a control device (not shown) to move the inkjet head 10 in the vertical direction (Z direction). The inkjet head 10 moves in the Y direction to a position facing the coating liquid removing device 17. In the middle of this, the ejection surface 12 of the inkjet head 10 does not face the stage 24 and the like, and the ejection surface 12 is exposed downward. At this time, the discharging surface 12 of the ink jet head 10 is discharged by blowing air containing discharging ions from the discharging device 26. Furthermore, since the discharge surface and the discharge port of the inkjet head 10 are charged by frictional charging with the cleaning tool of the coating liquid removing device 17, the discharging is performed when the coating liquid removing device 17 returns to the stage 24 after removing the surface. More preferably it is performed. As a result, the frictional charging with the coating liquid removing device 17 can be eliminated.

  FIG. 6 is a schematic view of the ink jet apparatus of the present invention as viewed from above. The inkjet head 10 extends in the X direction of the stage so as to be adjacent to the stage 24. Specifically, it is installed at a distance between the coating liquid removing device 17 and the stage 24 and is attached so as to be longer than the inkjet head 10 in the X-axis direction. When the inkjet support 23 including the inkjet head 10 moves in the Y direction, the ejection surface 12 of the inkjet head 10 does not face the stage 24 and the like, and the ejection surface 12 is exposed downward. At this time, the discharging surface 12 of the ink jet head 10 is discharged by blowing air containing discharging ions from the discharging device 26. The static elimination device 26 is installed so as to be below the ink jet head 10, and the shield electrode 31 faces the ink jet head 10 when viewed from above.

  Here, the charging of the ejection surface 12 of the inkjet head 10, the aggregation of the pigment fine particles, and the nozzle clogging due thereto will be described.

  According to the knowledge of the present inventors, the components such as the ejection surface 12 and the ejection port 20 of the inkjet head 10 are triboelectrically charged with the coating liquid when ejecting the coating liquid such as ink. Will occur. For example, when the coating liquid is positively charged, at the same time, the discharge surface 12 is negatively charged with a reverse polarity. The discharge surface 12 is composed of an electrically insulating liquid repellent layer, a protective layer, and the like, and the generated static charge cannot be leaked from the discharge surface 12 and is in an isolated state. An electric field is generated between the charged ejection surface 12 (configured with a liquid repellent layer or a protective layer) and a metal part grounded to 0V.

  In order to manufacture a high-definition color filter, an ink in which a high-definition pigment is highly dispersed is used. The finely divided pigment fine particles form an electric double layer in a charged state in a solvent. Therefore, pigment fine particles having the same polarity are dispersed and stabilized by electrostatic repulsion. However, when an external electric field is applied, the charged pigment fine particles move in the polarity direction opposite to the polarity of the charged particles by the electrophoretic force. Further, due to the dielectrophoretic force, the pigment fine particles move from a place where the electric field is weak to a place where the electric field is strong. For this reason, the more dispersible the solvent is due to electrostatic repulsion, the easier it is to migrate due to the influence of an external electric field, and the concentration of fine particles increases locally, and the particles tend to aggregate. In an environment where fine particles tend to aggregate, even if there is a liquid repellent layer, the pigment fine particles are likely to adhere to the member over a long period of time.

  According to the knowledge of the present inventors, this phenomenon can be confirmed by a simple experiment in which fine electrodes are inserted into ink. For example, an electrode made of 0.2 mmφ tungsten is sandwiched from the front and back sides with a sheet that is used as a protective layer for the discharge surface, and sealed with an adhesive. When a voltage of 1 kV is applied to the completely sealed electrode and immersed in ink, fine particles and foreign matter adhere to the sheet after several hundred hours. Further, if the electrode to which the voltage is applied is directly put into the ink without sealing with a sheet, it can be confirmed that the ink component crystallizes and precipitates around the electrode in about 6 hours.

  In the actual inkjet head 10, since the coating liquid near the ejection port 26 and the ejection surface 12 is continuously ejected from the ejection port, the influence of static electricity on the coating liquid is small. However, the inside of the nozzle is in a state filled with the coating liquid, and a state in which the local concentration of the fine particles is likely to be higher than that in the case where there is no charge is likely to aggregate and precipitate. Further, the ink pigment component tends to remain on the ejection surface 12 as compared with the case where there is no charge. That is, when the coating liquid containing the pigment fine particles passes through the place where the electric field exists, the pigment fine particles are easily aggregated.

  Although the electrophoretic force and the dielectrophoretic force due to the electric field are not so large, the smaller the particle size, the smaller the resistance force when moving in the solution, and aggregation is likely to occur even in the same electric field. In addition, the smaller the viscosity of the solvent, the smaller the resistance and the more likely aggregation occurs. Ink used in an inkjet head for producing a color filter with higher definition than conventional ones has small pigment fine particles and a small viscosity of the solution. Therefore, conventionally, agglomeration due to charging of the discharge port 20 and the discharge surface 12 is likely to occur, which causes the discharge port to be clogged.

  Further, when the discharge surface 12 of the inkjet head 10 is wiped off with a cleaning cloth or the like by the coating liquid removing means 17, the discharge surface 12 becomes more and more charged due to contact charging with the cleaning cloth or the like.

  As described above, according to the knowledge of the present inventors, the discharge surface 12 is easily charged easily, and when left in a charged state, the pigment fine particles as the coating liquid component are discharged from the discharge surface 12 and the discharge port 20 due to the influence of charging. It tends to aggregate. Accordingly, it is preferable to appropriately neutralize the charge using the neutralization device 26 of the inkjet head of the present invention.

  The operation of the static eliminator 26 will be described with reference to FIG. FIG. 3 is an enlarged view of the vicinity of the static eliminator of FIG. FIG. 3 shows a scene in which the inkjet head 10 passes near the neutralization device 26 of the present invention. The inkjet head 10 moves from the right to the left in the direction indicated by the arrow in the drawing. Usually, the inkjet head 10 is arranged as a single inkjet head 10 by integrating the R color inkjet head 19R, the G color inkjet head 19G, and the B color inkjet head 19G. The insulating member of the ejection port 20 and the ejection surface 12 of the inkjet head 10 is strongly charged by ejecting the ink that is the coating liquid in the previous coating process. Charging has a charge distribution in which the vicinity of the discharge port 20 is strong and charging becomes weaker around the discharge port 20.

  The static eliminator 26 is attached to the side surface of the stage 24 on which the glass substrate 25 to be applied is placed via a support. In the static elimination device 26, a static elimination electrode needle tip 33 that generates ions by corona discharge and a high voltage power source 22 for applying a high voltage are electrically connected by a high voltage cable 32. A shield electrode 31 is disposed in the vicinity of the static elimination electrode needle tip 33, and is connected to the ground of 0 V by the ground wire 30. The shield electrode 31 is arranged so as to surround the static elimination electrode needle tip 33, and the front of the static elimination electrode needle tip 33 is opened. The shield electrode 31 not only stably generates corona discharge, but also shields the electric field generated by the charge removal electrode needle tip. For this reason, it becomes difficult to irradiate ions having strong directivity in the direction in which the shield electrode 31 exists. In addition, since the influence of the electric field by the needle tip is small with respect to the ejection port 20 and the ejection surface 12 of the inkjet head 10, it is alleviated that ions are forcibly sprayed onto the inkjet head 10. The inkjet head having the ejection surface is neutralized when it moves by the moving means and passes above the neutralization device 26 described above.

  The static elimination electrode needle tip 33 of the static elimination device 26 does not face the ejection surface 12, and the direction of the needle tip is substantially parallel to the ejection surface 12. For this reason, the static elimination electrode needle 33 is hidden by the shield electrode 31 when viewed from the discharge surface 12 side. The direction of the needle tip and the ejection surface 12 may be substantially in a range of 180 degrees ± 20 degrees.

  Here, the positional relationship between the direction of the needle tip of the static elimination electrode needle tip 33 and the ejection surface 12 will be described. The direction of the needle tip of the static elimination electrode needle tip 33 with respect to the surface of the discharge surface 12 that is horizontal in the vertical direction is preferably in the range of 90 ° ± 30 ° with respect to the vertical direction. The static elimination electrode needle tip 33 located in the range and the discharge surface 12 are made substantially parallel. When the discharge surface is not horizontal in the vertical direction, the direction of the discharge surface and the needle tip of the static elimination electrode needle tip 33 is preferably in the range of 180 degrees ± 20 degrees, more preferably 180 degrees ± 10 degrees. It is preferable that

  The airflow ejecting means 27 is disposed on the lower side in the vertical direction of the static elimination electrode needle tip 33 of the static elimination device 26. An airflow control plate 34 is disposed in the airflow injection unit 27 and is connected to the air supply unit 29 by an air pipe 28. The direction of the airflow is directed toward the ejection surface 12 through the side (front surface) of the static elimination electrode needle tip 33. The airflow ejecting means 27 pushes out air from the air supply means 29 with a pump (not shown) so that air is ejected from the ejecting portion. The injection part is composed of a slit-shaped gap, and the slit can be adjusted with a bolt. From the slit, air blows out as a laminar flow, and the blown air flows vertically upward along the airflow control plate 34. The flow velocity of the jetted airflow is preferably 1 to 4 m / min. The type of air flow to be ejected may be an inert gas such as nitrogen or argon, but air that is inexpensive and easy to handle is preferably used.

  When a high voltage is applied to the static elimination electrode needle tip 33, positive and negative ions are generated by corona discharge in the vicinity of the static elimination electrode needle tip 33 due to a potential difference with the shield electrode 31. Usually, a voltage of 3 kV to 15 kV is applied to the static elimination electrode needle tip 33, and the generated ions are irradiated in the direction of the tip of the needle tip according to the ion wind (in the horizontal direction in FIG. 3), and the opening of the shield electrode 31 Leaking from.

  In the present invention, the direction of the ions irradiated with the tip of the needle and the direction of the airflow by the action of the airflow control plate 34 in the airflow ejection device 27 are arranged so as to be substantially orthogonal. In addition, the shield electrode 31 extends forward from the static elimination electrode needle tip 33 and is disposed so as to surround the static elimination electrode needle tip 33. The static elimination ions leaking from the opening of the shield electrode 31 ride on the air current ejected from the air current ejection device 27, reach the ejection surface 12, and neutralize the ejection port 20 and the resin plate 18. At this time, since the static elimination electrode needle tip 33 surrounded by the shield electrode does not face the ejection surface 12, the electric field due to the static elimination electrode needle tip 33 is less likely to be affected. As a result, exactly the same amount of reverse polarity ions can be sprayed according to the charge distribution of the ejection surface 12 including the ejection port 20, the resin plate 18, the liquid repellent layer, and the like, and sufficient static elimination is possible.

  Here, the direction of the ions irradiated from the static elimination electrode needle tip 33 and the direction of the airflow are almost perpendicular to each other as follows. This is when the irradiation direction of the central portion of the irradiated ions and the direction of the airflow form an angle of 70 to 110 degrees. The irradiation direction of the central portion of the irradiated ions substantially coincides with the direction of the needle tip of the static elimination electrode needle tip 33. Therefore, it is preferable that the direction of the air flow is in the range of 90 ° ± 20 ° with respect to the surface of the discharge surface 12 which is horizontal in the vertical direction.

  When the neutralization electrode needle tip 33 and the ejection surface 12 are in the normal close proximity to each other, the ejection surface 12 cannot be sufficiently neutralized. This is because the static elimination ions are carried by the electric field, but since the electric field of the static elimination electrode needle tip 33 has a strong influence, the generated static elimination ions are likely to be forcibly sprayed onto the ejection surface 12 and reflect the charge distribution state of the static elimination object. This is because it is difficult to forcibly irradiate the ionizing ions. For this reason, it is charged in an insufficient state where the charge distribution remains, or on the contrary, reverse polarity.

  In addition, it is conceivable to perform neutralization by bringing a conductive brush or blade-shaped neutralization member into contact with the discharge surface 12 and sliding relatively, but in the neutralization by the brush-shaped neutralization member, the discharge surface of the nozzle plate Since there are portions that come into contact with the brush and portions that do not come into contact with the brush, non-uniformity occurs in static elimination.

  This is the installation position of the charge removal device 26 for removing the discharge surface 12 and the discharge port 20 and the like. When moving from the stage 24 to the coating liquid removal device 17 to clean the nozzle, the charge removal is performed toward the lower surface of the nozzle. However, the position of the static eliminator 26 is not limited to this. The vicinity of the coating liquid removing apparatus 17 may be used, or the stage 24 may be provided with a step or the like.

  Further, although the interval of the static elimination operation depends on the color filter application state and the ink characteristics, it may be basically performed before or after the cleaning process in accordance with the nozzle cleaning cycle.

  In addition to the charge removal device for the discharge surface 12, a charge remover for another purpose may be installed in the coating device. For example, in order to neutralize the glass substrate 25 set on the stage 24, those using ions generated by corona discharge and those neutralizing by irradiating with soft X-rays are preferably used.

  Next, another embodiment of the present invention will be described.

For discharging the discharge surface 12 and the discharge port 20, the surface resistivity of the outermost surface such as the protective film and the liquid repellent layer constituting the discharge port 21 and the discharge surface 12 is 10 ⁶ Ω / □ or more and 10 ¹⁰ Ω / □ or less. It is also achieved by performing the antistatic treatment. Note that the surface subjected to the antistatic treatment having a surface resistivity of 10 ⁶ Ω / □ or more and 10 ¹⁰ Ω / □ or less needs to be grounded. In the present invention, the surface resistivity is measured by the resistivity measured by ASTM D-257 (measurement temperature 25 ° C.). As one form of grounding in the present invention, it is attached to a metal frame by a housing or a peripheral member, and the metal frame is electrically connected to a grounding point such as a building. When the resistance to ground is measured by a tester, it means 10V or less.

  For the liquid repellent layer on the ejection surface 12, it is preferable to select a liquid repellent treatment method according to the liquid. Liquid repellent treatment methods include electrodeposition of cationic or anionic fluorine-containing resins, fluorine polymer, silicone resin, polydimethylsiloxane coating, sintering method, eutectoid plating method of fluorine polymers, amorphous Deposition method of alloy thin film, Method of attaching a film of organic silicon compound or fluorine-containing silicone compound mainly composed of polydimethylsiloxane based on plasma polymerization of hexamethyldisiloxane as monomer by plasma CVD method There is. When performing the liquid repellent treatment, a desired surface resistivity can be obtained by mixing a small amount of a conductive compound or a conductive polymer.

The protective film around the discharge port 20 and the inner wall has, for example, antistatic performance by applying a quaternary ammonium silane compound on the surface of the first discharge-resistant protective film and then irradiating it with an electron beam. A protective film can be formed. By this surface treatment, the surface resistivity can be 10 ⁹ Ω / □. Further, the antistatic layer of the quaternary ammonium silane compound that has been irradiated with an electron beam to cause a crosslinking reaction can have a pencil hardness of H to 2H.

  As described above, in the prior art, the charging and discharging of the lower surface of the nozzle of the inkjet head were not sufficient, but by applying the present invention, the discharging of the lower surface of the inkjet nozzle was performed and the charge distribution was eliminated. Clogging can be eliminated.

Examples of manufacturing color filters will be described below, but the present invention is not limited to these examples.
[Example 1]
As shown in FIG. 2, the ink jet head 10 was used in which the ejection surface 12 had three rows of ejection ports 21 in a zigzag pattern, a Y direction pitch of 70.5 μm, and a total of 512. From each discharge port 21, it was possible to intermittently discharge 20 to 40 pl of coating liquid per time by driving the piezoelectric element. Adjacent R, G, and B ink jet heads 19R, 19B, and 19G were integrated to form the ink jet head 10. Regarding the outer shape of the inkjet head 10, the Y-direction length W1 of the ejection surface 12 was 80 mm, and the X-direction length was 36 mm. The length of the resin plate 18 in the Y direction was 60 mm, and the length in the X direction was 16 mm. A 75 μm thick polyimide resin layer coated with a liquid repellent layer was provided as the resin plate 18.

  On a non-alkali glass substrate of 360 × 465 mm and a thickness of 0.7 mm, each pixel has a width of 75 μm, a length of 200 μm, a black matrix width of 20 μm, and a black matrix with liquid repellency on the surface A black matrix substrate was prepared. 200 μl of RGB color coating liquid per pixel was ejected from the inkjet head 10 to form a coating film on the entire surface.

  As the coating solution, an R color coating solution having an R color pigment, a viscosity of 10 mPas, and a solid content concentration of 15% was used. The G color coating solution had a G color pigment and had a viscosity of 12 mPas and a solid content concentration of 16%. The B color coating solution had a B color pigment and had a viscosity of 11 mPas and a solid content concentration of 11%.

  The static eliminator 26 was provided with a plate on the side surface of the frame surrounding the stage 24 (2000 mm × 2500 mm), and was fixed with screws attached to the static eliminator 26. At this time, the direction of the needle of the static elimination electrode needle tip 33 and the ejection surface 12 of the moving inkjet head were arranged in parallel. The distance was adjusted to 80 mm up to the outermost layer of the discharge surface 12.

The neutralization device 26 and the airflow injection device 27 use a model 957 (manufactured by Meech) air curtain type static eliminator. A commercial frequency AC voltage was applied. In addition, in order to control the flow of the air flow and the direction of diffusion of the static elimination ions, the direction of the static elimination electrode needle tip of Model 957 was set in a state where the orientation was changed by approximately 90 degrees. Air passed through the filter was introduced from the airflow supply means 29 at a pressure of 0.2 MP / m ² and introduced into the airflow injection means 27 via a tube made of “Teflon” (registered trademark). The flow velocity of the air jetted from the airflow injection means 27 and flowing along the airflow control plate 34 was a laminar flow of 2 m / sec.

  Using this static eliminator 26, a +/− 2 kV charging plate (size 50 mm × 80 mm) was placed in the vicinity of the ejection surface 12, and the static ionic current value was measured, and was −0.4 μA to +0.3 μA. It was.

  When the color filter was manufactured with the apparatus of the present invention, the charging of the discharge surface 12 changed before and after the charge removal apparatus 26. When the charge on the discharge surface 12 was measured with a MODEL520 (manufactured by TREk) surface potential meter, it was -600V to -400V before neutralization, but when the charge was removed by passing through the neutralization device 26, the surface potential was -2V to + 3V. Was found to be uncharged. Further, when the charge amount distribution state was visualized with a fine powder, no adhesion of the fine powder was observed over the entire surface after static elimination.

When a color filter was manufactured by the apparatus of the present invention, nozzle clogging did not occur and abnormal flight bending of ink droplets did not occur within 6 months, and good pixel formation could be achieved.
[Example 2]
In Example 1, an example in which the surface resistivity of the discharge surface 12 is lowered to eliminate the charge will be described below. In addition, although the static elimination apparatus 26 was used in Example 1, favorable applicability | paintability was obtained in any case, even if it was not used together with the static elimination apparatus 26 in Example 2.

On the discharge surface 12, 1% of carbon black was added to the liquid repellent layer made of a silicone resin formed on the surface of the polyimide resin. When measured by ASTM D-257 (measurement temperature 25 ° C.), the surface resistivity of this liquid repellent layer was 10 ⁸ Ω / □. One end of the liquid repellent layer was brought into contact with a metal part in the nozzle head and grounded.

When a color filter was manufactured with the apparatus of the present invention, it was found that the discharge surface 12 was not charged because the surface potential dropped from −2 V to +2 V. Further, when the charge amount distribution state was visualized with fine powder, adhesion of the fine powder was not observed over the entire surface.
[Comparative Example 1]
In the configuration of the example, the color filter was manufactured without using the static eliminating device 26. When operation was continued for 3 months while the discharge surface 12 was charged, the flight of ink droplets was bent at the time of pixel formation, and color mixing occurred in adjacent pixels. When the operation was continued as it was, it gradually deteriorated, and adhering foreign matter was generated in a donut shape at some inkjet discharge ports. Moreover, it was observed that the adhering foreign material adhered to a part of the resin plate 18 on the discharge surface 12.

  The static eliminator of the present invention can be applied to a static eliminator method in the case of using an electrically insulating resin member in a coating method in which a coating liquid is discharged from a fine hole or slit. It is not limited.

DESCRIPTION OF SYMBOLS 10: Inkjet head 12: Ejection surface 13: Piping 14: R color coating liquid supply apparatus 15: G color coating liquid supply apparatus 16: B color coating liquid supply apparatus 17: Coating liquid removal apparatus 18: Resin plate 19R: R color inkjet Head 19G: G-color inkjet head 19B: B-color inkjet head 20: Ejection port 21: Ejection port 22: High-voltage power supply 23: Inkjet support 24: Stage 25: Glass base material 26: Static elimination device 27: Airflow ejection means 28: Air Piping 29: Air supply means 30: Grounding wire 31: Shield electrode 32: High voltage cable 33: Static elimination electrode needle tip 34: Airflow control plate 100: Liquid repellent film 101: First discharge liquid protection film 102: Second resistance film Discharge liquid protective film 103: Third discharge liquid protective film 105: Solidified substance 108: Nozzle 110: Face plate 111: Base Member 115: neutralizing electrode 124: conductive plate 125 provided in the nozzle: ink buffer

Claims (4)

A discharge method for an ink jet head having a discharge port for discharging a coating liquid and a discharge surface including the discharge port, wherein the ions are discharged from a needle tip of a discharge electrode provided at a lower position facing the discharge surface. Irradiated in a direction substantially parallel to the surface, the irradiated ions are ejected upward by an air current ejecting means provided at a position below the static elimination electrode, and the ions are applied to the ejection surface by being placed on the air stream. A discharging method for an ink jet head, wherein the discharging surface is discharged by spraying. A neutralization device for neutralizing an inkjet head having an ejection port for ejecting a coating liquid and an ejection surface including the ejection port, and a neutralization electrode for neutralizing the ejection surface of the inkjet head moved by a moving unit A needle having a needle, and the tip of the static elimination electrode needle is arranged so that the extending direction of the tip of the static elimination electrode needle is substantially parallel to the ejection surface of the inkjet head moved by the moving means And an air current ejecting means for spraying ions generated at the tip of the static elimination electrode needle to the ejection surface of the ink jet head moved by the moving means by an air current. . The static elimination electrode needle, and a shield electrode having an opening surrounding the static elimination electrode needle, wherein the shield electrode is disposed in front of a tip of the static elimination electrode needle in the extending direction of the static elimination electrode needle, and the static elimination electrode 3. The static eliminator for an ink jet head according to claim 2, wherein ions generated at the tip of the electrode needle are irradiated from an opening of the front shield electrode. A method for producing a color filter, comprising: producing a color filter using the method for neutralizing an ink jet head according to claim 1 or using the device for neutralizing an ink jet head according to claim 2 or 3.

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