JP2010036149A - Cleaning method of coating head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method of coating head capable of efficiently removing fluorescent material paste attached to an ejection hole and an ejection surface of a coating head and capable of reducing flaws inflicted on the coating head by wiping. <P>SOLUTION: The cleaning method of coating head of cleaning coating liquid attached to the ejection hole of the coating head on which a plurality of ejection holes are arranged in a line and attached to the surrounding of the ejection hole comprises: a step of retaining a pushing member for a predetermined time while causing the surrounding of the ejection hole of the coating head 6 to contact with a wiping member 7 supported by the pushing member made of an elastomer; a step of separating the coating head from the wiping member to transfer the coating liquid to the wiping member; and a subsequent step of relatively moving the coating head and the wiping member in one direction while causing the wiping member supported by the pushing member to contact with the surrounding of the ejection hole of the coating head to perform sliding wiping. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for cleaning a paste attached to the periphery of a discharge hole and a discharge hole of a coating head.

In recent years, large flat display panels such as plasma displays, liquid crystal displays, and field emission deathlays have been developed, forming a large market.
Among these, the plasma display generates a plasma discharge between the anode and cathode electrodes facing each other in the discharge space formed between the front substrate and the back substrate, and the Xe-Ne mixture injected into the discharge space. Color display is performed by emitting ultraviolet light such as 147 nm and 172 nm generated from a discharge gas such as a gas to phosphor layers provided in discharge spaces of R (red), G (green), and B (blue) colors. Is what you do. In general, the back plate of a plasma display is provided with barrier ribs (also referred to as barriers or ribs) in order to suppress the spread of discharge to a certain area and perform display within a specified cell, while ensuring a uniform discharge space. It has been. The shape of the partition generally includes a stripe shape or a lattice shape having a width of 20 to 120 μm and a height of 50 to 250 μm. The phosphor layer is formed by applying a phosphor paste mainly composed of phosphor powder, an organic binder, and an organic solvent between predetermined partitions, drying, and firing as necessary. Since this phosphor paste contains phosphor powder at a high concentration, it often has a high viscosity of 10,000 mPa · s or more.

  As a method for applying the phosphor paste between predetermined barrier ribs, there are a screen printing method, a dispenser method, and the like, and a dispenser method with little material loss is attracting attention.

  In the dispenser method, a phosphor paste is applied between barrier ribs using an apparatus including a coating head having a discharge hole through which paste is discharged, while the coating head and a substrate are opposed to each other and relatively moved. In the case of a plasma display, a phosphor paste is applied between the barrier ribs. In this case, it is often a single-wafer method in which application is performed for each substrate, and application starts and ends for each substrate, and before and after the discharge start and discharge stop of the phosphor paste discharge holes are performed. Do. After the application to one substrate is finished and the discharge of the phosphor paste is stopped, the phosphor paste adheres to the discharge holes and around the discharge holes of the application head. If this is done, the discharge flow of the phosphor paste discharged from the discharge holes is disturbed, and accurate application cannot be performed between the predetermined partition walls. Therefore, in order to maintain accurate coating accuracy, it is necessary to clean the ejection holes and ejection surface of the coating head every time after the coating is completed.

  As such a coating head cleaning method, conventionally, as shown in FIG. 6, a method of scraping and cleaning a coating liquid such as a phosphor paste adhering to the discharge hole and the discharge surface with a scraper made of an elastic material such as rubber. (See Patent Document 1) and a method shown in FIG. 7 that wipes slidingly by relatively moving a wiping material such as a soft cloth supported by a pressing means and an application head (see Patent Document 2). However, in these methods, for example, in the case of a phosphor paste for a plasma display, the phosphor powder, which is hard inorganic fine particles contained in the phosphor paste, moves relative to the discharge hole in a pressed state, The periphery of the discharge hole of the coating head is shaved. As a result, as shown in the schematic diagram of FIG. In addition, the wiping damage becomes deeper as the number of wiping increases. If the depth of wiping scratches exceeds a certain limit, a coating defect occurs and high quality coating cannot be performed. If the coating head cannot be used due to the wiping scratches, a new coating head must be manufactured, and the cost is high and it takes time to replace the coating head, resulting in poor production efficiency.

On the other hand, as another cleaning method, a wiping member such as a soft sheet-like cloth or film is supported and pressed against an inkjet coating head of a low-viscosity coating liquid by an elastically deforming pressing means and absorbed by the wiping member (patent Document 3) is known. However, in the case of a coating liquid having a high viscosity and a large amount of phosphor powder such as a phosphor paste of a plasma display, the phosphor paste adhering to the periphery of the discharge hole 1 of the coating head is removed only by being absorbed by the wiping member. Is difficult.
JP 2004-14393 A JP 2002-126599 A JP 2007-30482 A

  The present invention cleans the paste adhering to the application head without damaging the periphery of the application head by sliding wiping using a wiping member, and generates scratches around the application head. By reducing the length of the coating head, a coating head cleaning method for extending the life of the coating head and realizing coating with high productivity is provided.

  In order to solve the above-mentioned problems, the present invention provides a coating head cleaning method for cleaning a coating liquid that adheres to the discharge holes of a coating head in which a plurality of ejection holes are arranged in a row and the periphery of the discharge holes. The discharge hole periphery is held for a predetermined time in contact with the wiping member supported by the pressing means, the coating head and the wiping member are separated and the coating liquid is transferred to the wiping member, and then the coating head Provided is a coating head cleaning method, wherein the coating head and the wiping member are relatively moved in one direction and wiped by sliding while the wiping member supported by a pressing means is in contact with the periphery of the discharge hole.

  In the present invention, the wiping member is supported by a pressing means having a cylindrical surface to perform sliding wiping, and during the relative movement, the wiping member supported at the uppermost position of the cylindrical surface of the pressing member is It is preferable to pass through the discharge hole of the coating head.

  In the present invention, the wiping member is supported by a pressing means having a cylindrical surface whose central axis is parallel to the arrangement direction of the discharge holes of the coating head, and the wiping member supported at a position other than the uppermost position of the cylindrical surface. Holding the periphery of the discharge hole of the coating head for a predetermined time, separating the coating head and the wiping member, transferring the coating liquid to the wiping member, and then using the same cylindrical surface of the same pressing member It is preferable to perform sliding wiping using a wiping member other than the portion to which the coating liquid of the supported wiping member is transferred.

  When the coating head cleaning method of the present invention is used, it is possible to reduce the scratches generated around the ejection holes and around the ejection holes of the coating head, thereby extending the life of the coating head. Moreover, a low-cost and simple application head cleaning method can be provided.

  The present invention includes a step of wiping the coating liquid with the wiping member after the coating liquid adhering to the discharge hole of the coating head and around the discharge hole is brought into contact with the wiping member and transferred to the wiping member by separating the coating liquid. The present invention relates to a coating head cleaning method.

  In the present invention, the coating head refers to a member such as a coating nozzle or a base constituting a coating apparatus, in which ejection holes for ejecting a coating liquid are arranged in a line. The discharge hole refers to an opening through which the coating liquid supplied to the coating head is discharged toward the object to be coated. Further, the periphery of the discharge hole is a region near the outer edge of the discharge hole, and if coating is performed with the coating liquid remaining in this region, the quality of the coating is significantly impaired. The discharge hole may have any shape such as a slit shape, a circle shape, an ellipse shape, or a polygonal shape. However, when the coating head is a phosphor coating head for plasma display, it is necessary for one screen in the plasma display. The phosphor layer is arranged in the longitudinal direction of the coating head in a number more than the number (about 1000 to 4000) according to the number of pixels in the scanning direction so that the phosphor layer can be applied by one ejection for each of R, G, and B colors. Is preferred. When the discharge hole is circular, the diameter is preferably about 50 to 200 μm.

  In the present invention, the separation refers to a step of separating the two after separating the application head from the wiping member. In addition, the wiping member is preferably a flexible material such as cloth or film. In the present invention, the wiping member is an ultrafine fiber of 0.1 dtex or less, and is composed of knitted fabric, woven fabric or non-woven clothing having a low dust generation property, and absorbs per unit volume. A large amount and a thickness of 0.25 to 0.4 mm are preferred.

  The pressing member that supports the wiping member is made of an elastic body, and at least a part of the pressing member is a cylindrical surface so that a uniform pressing can be obtained on the discharge surface of the coating head when contacting with the coating head or sliding wiping. It is preferable to have a cylindrical roll shape that is easy to manufacture. The diameter of the cylindrical surface is preferably 30 to 100 mm. If the diameter is larger than 100 mm, it becomes difficult to press the top surface of the cylindrical surface against the discharge surface of the coating head, which may cause wiping failure during sliding wiping. There is not preferable. When the thickness is less than 30 mm, the contact surface between the coating head and the elastic body becomes small, and thus there are cases where the coating liquid adhering to the ejection holes and the periphery of the ejection holes cannot be wiped off during transfer or sliding wiping.

  Further, the straightness representing the straight line undulation in the longitudinal direction of the cylindrical surface is preferably 1000 μm or less per 1 m in the longitudinal direction of the cylindrical surface, and more preferably 100 μm or less. When the straightness per 1 m in the longitudinal direction is larger than 1000 μm, it is not preferable because a portion that cannot be wiped off by sliding wiping is likely to occur. The cylindrical surface preferably has an axis parallel to the arrangement direction of the discharge holes of the coating head. If the arrangement direction of the discharge holes of the cylindrical surface and the coating head is not parallel, the coating head is not uniformly pressed when the coating head is transferred to the wiping member, and transfer unevenness is likely to occur. Further, since uniform pressing cannot be obtained even during sliding wiping, unwiped portions of the coating liquid are generated, which is not preferable. The parallelism indicating the degree of parallelism between the cylindrical surface and the arrangement direction of the discharge holes of the coating head is preferably 0.2 mm or less per length. If the parallelism is greater than 0.2 mm per 1 m length, the cylindrical surface cannot make uniform contact with the coating head, such being undesirable. The hardness of the elastic body does not suffer damage such as residual strain even after repeated contact, and with moderate softness, follows the shape of the contacted counterpart, and quickly recovers to the original cylindrical shape when the coating head is separated Those are preferred. The rubber hardness is preferably A10 to A30 degrees (JIS K 6253 (2006)). If it is larger than A30 degrees, the elasticity is impaired, and the elastic body does not conform to the shape of the coating head when it comes into contact with the coating head. When the rubber hardness is smaller than A10 degrees, a pressing pressure cannot be obtained, which is not preferable.

As the material of the elastic body, it is preferable to use foaming sponge, synthetic rubber or the like. Specifically, silicone resin sponge, polyethylene sponge, fluorine resin sponge, silicone rubber, fluorine rubber, butyl rubber, and pig ethylene rubber are preferable.
The thickness of the elastic body is preferably 3 to 30 mm, and more preferably 5 to 15 mm. If the thickness is less than 3 mm, the elasticity is impaired, and if it is more than 30 mm, unnecessary materials increase, and the apparatus becomes large and uneconomical. In order to adjust the hardness, a cover such as a resin film may be provided on the surface. If it carries out like this, in the case of the elastic body which has no tolerance to a washing | cleaning solvent, an elastic body can be protected from the solvent component which oozes out from a wiping material.

  The present invention separates the coating head after coming into contact with the wiping member, transfers the coating liquid adhering to the periphery of the discharge hole of the coating head to the wiping member, and reduces the coating liquid adhered to the coating head, and then performs sliding wiping. Thus, scratches around the discharge holes of the coating head can be reduced, and the coating liquid can be reliably removed.

  The coating head cleaning method of the present invention preferably uses a phosphor coating nozzle for manufacturing a plasma display as the coating head, and uses a phosphor paste as the coating liquid. Hereinafter, although the example of the coating head cleaning method in the case of apply | coating fluorescent substance paste using the fluorescent substance application nozzle for plasma display manufacture is demonstrated, this invention is not limited to this.

The apparatus structure of this invention is demonstrated with the schematic of the cleaning apparatus cross section of FIG.
The inside of the coating head 6 is filled with a phosphor paste 15, and a gas such as compressed air is introduced from the gas pressure inlet 14, and the phosphor paste 15 is ejected from the ejection holes 1 for coating. After the discharge of the phosphor paste is stopped, the attached paste 13 is attached around the discharge hole 1.

  The frame 5 is provided with a wiping member 7, a pressing member 16, a pressing member 17, a winding device 10, and an unwinding device 11. The frame 5 can be transferred from the apparatus, and the wiping member 7 can be prepared by external setup. The wiping member 7 is a continuous web and is wound into a roll. Further, the wiping member 7 is supported by the pressing member 16, the elastic body 9 and the elastic body 12 provided on the pressing member 17, unwound from the unwinding device 11, and taken up by the winding device 10.

  In the embodiment shown in FIG. 2, the number of pressing members is two, but the number of pressing members may be one or more. The winding device 10 and the unwinding device 11 are driven by a motor (not shown) and the tension of the wiping member 7 is always applied to the wiping member 7 without wrinkles on the elastic body 16 and the elastic body 17. It is preferable to wind with the motor of the winding device 10 while applying torque with the torque motor.

  The pressing amount when the discharge surface 3 of the coating head 6 is brought into contact with the elastic body 9 and the adhered paste 13 is transferred to the wiping member is the contact position between the discharge surface 3 of the coating head 6 and the uppermost cylindrical surface of the elastic body 9. From 0.2 to 3.0 mm. When the pressing amount is 0.2 mm or less, the pressure necessary for wiping is not obtained during sliding wiping, and the attached paste 13 attached to the coating head cannot be transferred to the wiping member 7. Uncleaned paste is generated on the discharge surface. Further, the pushing amount when slidingly wiping the coating head 6 and the elastic body 12 is also 0.2 to 2.0 mm, preferably 0.2 to 1.5 mm. When the push-in amount is 1.5 mm or more, when the coating head passes the uppermost cylindrical surface during sliding wiping, the pressure on the coating head may be excessively increased and the discharge hole 1 may be damaged. Absent.

  FIG. 3 is a schematic view of a cross section of the cleaning device showing the first embodiment of the present invention, after transferring the coating head to the wiping member supported by the pressing member, separating the coating head from the wiping member, It is an example showing a method of performing sliding wiping by bringing the coating head into contact with the same wiping member supported by another pressing member again. Hereinafter, the cleaning process of the present invention will be described in order.

  FIG. 3A is a process of contacting the wiping member 7 supported by the pressing member 16 with the adhesive paste 13 attached to the coating head 6.

  The contact position is preferably the uppermost cylindrical portion of the elastic body 9 provided on the pressing member 16 because an appropriate contact pressure may be obtained. However, the contact pressure necessary for transfer may be obtained even if the contact position is slightly deviated. .

  In order to transfer the phosphor paste to the wiping member 7 at the time of contact, it is preferable to provide a certain contact holding time. The holding time is set according to the characteristics of the phosphor paste and the characteristics of the wiping member 7, but is preferably about 0.5 to 10 seconds, more preferably 2 to 5 seconds. When the holding time is less than 0.5 seconds, the amount of the phosphor paste transferred to the wiping member 7 is reduced. As a result, in the next sliding wiping step, the amount of the phosphor paste to be wiped out increases, and the phosphor paste is easily left unwiped, and the discharge surface 3 is easily damaged by the phosphor powder.

  On the other hand, when the holding time is longer than 10 seconds, a large amount of the phosphor paste is transferred to the wiping member 7, but when the holding time is long, the production tact becomes long and the productivity is impaired, which is not preferable.

  Next, FIG. 3B shows an example of a process operation in which the application head is moved in the vertical direction after the adhered paste 13 is brought into contact with the wiping member 7, and the application head 6 is separated from the wiping member 7. Separation is preferable because the adhered paste 13 is transferred to the wiping member 7 and the amount of phosphor paste adhered to the periphery of the discharge hole 1 is reduced.

  Next, the coating head 6 is moved again onto the pressing member 17 shown in FIG. 3C, and the coating head 6 is applied to the wiping member 7 supported by the pressing member 17 as shown in FIG. Make contact. Next, as shown in FIG. 3E, sliding wiping is performed by relatively moving the coating head so that the coating head 6 passes through the uppermost cylindrical surface of the elastic body 12 provided on the pressing member 17. In this embodiment, the coating head 6 is moved in the vertical and horizontal directions. However, the wiping member 7 may be relatively moved by moving the frame 5. The pressing member 16 and the wiping member 17 have a cylindrical roll shape with a diameter of 80 mm in which an elastic body is wound around a mandrel that can be easily manufactured. However, the present invention is not limited to this, and the roll diameter may be varied. . Moreover, it is preferable that the arrangement direction of the discharge holes of the coating head 6 and the central axis of the cylindrical surface installed on the pressing member are parallel. Although the wiping member 7 supported by the pressing member 16 and the pressing member 17 is the same, different types of wiping members may be used. In this case, it is preferable to install a winding device and an unwinding device on each wiping member.

  FIG. 4 is a schematic view of a cross section of the cleaning device showing the second embodiment of the present invention, and is an example showing a method of performing transfer and sliding wiping on the cylindrical surface of one pressing member. Hereinafter, the cleaning process of the present invention will be described in order.

  FIG. 4A shows a process of transferring the adhesion paste 13 to the wiping member 7 supported by the pressing member 16, and it is preferable to provide a contact holding time in order to transfer the phosphor paste to the wiping member 7. The holding time is the same as in the embodiment of FIG.

  The contact position is a contact position 18 that is shifted 2.0 to 4.0 mm toward the winding device 10 with the cylindrical surface uppermost 19 of the elastic body 9 as a boundary. In the case of 4.0 mm or more, the contact with the ejection surface 3 is reduced, and in the case of 2.0 mm or less, the phosphor paste easily adheres to the wiping member supported at the top of the cylindrical surface used in the next process. Therefore, it is not preferable. Next, FIG. 4B shows a process of moving the coating head 6 in the vertical direction after the adhesive paste 13 is transferred to the wiping member 7 and separating the coating head 6 from the wiping member 7. Separation is preferable because the amount of phosphor paste around the discharge hole 1 is reduced.

  Next, the coating head 6 is again brought into contact with the second contact position 20 shown in FIG. The second contact position 20 is between the first contact position 18 in FIG. 4A and the uppermost surface 19 of the cylindrical surface of the elastic body 9 installed on the pressing member 16, and the first contact position. Therefore, it is preferable that the transfer paste 22 transferred to the wiping member 7 does not reattach to the vicinity of the discharge hole 1 of the coating head 6 and the wiping member 7 is a clean portion that is not contaminated with the paste. Note that the direction in which the coating head is separated after the first contact may be separated obliquely upward so as to be directly above the second contact position 20.

  Next, FIG. 4D shows an example of the process of performing the sliding wiping by moving the coating head 6 and the wiping member 7 relative to each other. In this sliding wiping step, the phosphor adhered to the ejection surface 3 of the coating head 6 by passing the ejection surface 3 of the coating head 6 through the uppermost surface 19 of the cylindrical surface of the elastic body 9 installed on the pressing member 16. This is preferable because the paste can be reliably wiped off. Moreover, the amount of the phosphor paste wiped off in the sliding wiping step is reduced by transferring the attached paste 13 attached to the coating head 6 to the wiping member 7 (steps of FIG. 4A and FIG. 4B). Since the contact between the phosphor powder in the phosphor paste and the ejection surface of the coating head 6 is reduced, it is preferable that wiping scratches generated around the ejection holes 1 of the coating head 6 can be reduced.

  Here, it is preferable that the winding device 10 is disposed on the side where the coating head 6 is brought into contact with the cylindrical surface top 19 of the pressing member 16 as a boundary, and is wound in one direction. As a result, the transfer paste 22 transferred to the wiping member 7 does not pass through the uppermost cylindrical surface 19 of the pressing member, and the wiping member 7 that is not contaminated with the phosphor paste always comes to the uppermost cylindrical surface 19. Since it can wind up like this, it is preferable. In addition, since the wiping member 7 is not taken up by the take-up device 10 between the transfer process and the sliding process in this way, the time required for winding can be reduced, so that the tact is not increased and the use of the wiping cloth is made more efficient. Although it is possible, it is preferable, but the wiping member may be wound up between both steps.

  Moreover, as shown in FIG.4 (e), the area | region where the paste 23 adhered after wiping on the wiping member 7 can still fully transfer the phosphor paste by the sliding wiping using the wiping member 7. Then, it is preferable that the wiping member 7 is reused for the next transfer and the amount of use can be reduced by sending it to the contact position 18 in the transfer step before the application head is cleaned. Furthermore, the replacement frequency of the wiping member 7 can also be reduced, and productivity can be improved.

  According to this embodiment, it is possible to reduce the wiping scratches generated on the ejection surface 3 of the coating head with a single pressing member and to clean it reliably, and it is only necessary to have one pressing member, thus simplifying the apparatus configuration. This is preferable because it is possible.

  In each sliding wiping process described above, a cleaning liquid may be applied to the wiping member 7 before the sliding wiping process. It is preferable because the scratches can be further reduced by the wetting effect of the cleaning liquid. For the application of the cleaning liquid, known means such as spraying and dropping can be used.

  When this cleaning liquid has a single cylindrical surface of the elastic body, it is preferable to use a cleaning liquid having a boiling point of 80 ° C. or less so that the cleaning liquid does not remain around the discharge surface 3 of the coating head 6 after sliding wiping. Specifically, acetone and ethanol are preferable.

  On the other hand, when there are a plurality of pressing means, a low-volatility cleaning liquid having a boiling point of 90 to 300 ° C. may be used for further wetting. In that case, the coating head is used in the transfer step shown in FIG. It is preferable to apply the cleaning liquid to the wiping member 7 at the contact position 18 of the pressing member 16 to be contacted, and the wiping member 7 supported by the pressing member 17 in the sliding wiping process is not wet with the cleaning liquid. Is preferred. Thus, the residual cleaning liquid 25 and the adhering paste 13 remaining in the vicinity of the discharge hole 1 of the coating head 6 after the transfer shown in FIG. 5 (c) are slidably wiped as shown in FIGS. 5 (e) and 5 (f). It can wipe off with the wiping member 7 supported by the pressing member B17 in the process.

  Specifically, the cleaning liquid used is 4-methyl-2-pentanol, 2-propanol, diacetone alcohol, hexanol, heptanol, octanol, nonanol, isononyl alcohol, isodecanol, terpineol, benzine alcohol, butyl acetate, Acetic acid-3methylbutyl, ethylene glycol monobutyl ether and the like are preferable.

Example An example in which the embodiment of FIG. 4 is applied to cleaning a phosphor paste coating head for a plasma display will be described below, but the present invention is not limited to this example.

  The phosphor paste used was prepared by the following method. A phosphor paste was prepared by dispersing and mixing in a 16 wt% terpineol / benzyl alcohol (3/1) solution of ethyl cellulose having a weight ratio of 19 and a weight ratio of the inorganic phosphor powder of 19. The phosphor powder used is (Y, Gd) BO3: Eu for red light emission, ZnSiO4: Mn for green light emission, and BaMgAl10O17: Eu for blue light emission. The cumulative average particle size and the maximum particle size of each color phosphor powder are R phosphor: 2.7 μm, 27 μm, B phosphor: 3.7 μm, 27 μm, G phosphor: 3.6 μm, 25 μm. The respective viscosities are R phosphor: 52000 mPa · s, B phosphor: 39000 mPa · s, and G phosphor: 40000 mPa · s.

  The coating head for applying the phosphor paste is a coating head having 1922 holes and a discharge hole having a hole diameter of 100 μm. The paste is discharged from the discharge holes by applying a pressure of 200 to 700 kPa with air to the predetermined partition walls. A phosphor paste is applied between them. As a coating apparatus for coating using a coating head, a stage having an XYZθ4 axis, a control unit for controlling and driving the XYZθ4 axis, a storage control unit for controlling the operation of the coating apparatus and the cleaning apparatus with a predetermined program, and the like The coating apparatus used was used. As the wiping member 7, a knitted fabric of ultra-fine fibers (“Toraysee” manufactured by Toray Industries, Inc.) is used, and a tension of 4 kg / m is applied so that wrinkles do not occur on the elastic body 9. As the pressing member 16, a cylindrical roll of a silicone resin sponge having a rubber hardness of A15 (JIS K 6253 (2006)) and a thickness of 15 mm was used. The diameter of the pressing member 16 including the silicone resin sponge is 80 mm. In order to transfer and absorb the phosphor paste adhered to the coating head 6 on which the phosphor paste is adhered to the wiping member 7, the contact position 18 for contacting the coating head 6 with the wiping member 7 is from the top 19 of the cylindrical surface. The position where the application head 6 is pushed into the elastic body A9 is shifted by 2.0 mm, and the amount of the application head 6 pushed in by 1.0 mm from the contact position between the application head 6 and the wiping member 7 supported by the uppermost cylindrical surface 19 of the elastic body. It was. The holding time for transfer / absorption was 5 seconds.

  The second contact position in the sliding wiping step is a position shifted by 0.5 mm from the uppermost surface 19 of the cylindrical surface of the elastic body 9, and the pushing amount is between the coating head 6 and the wiping member 7 supported by the uppermost surface 19 of the cylindrical surface. This is the amount pushed 0.5 mm from the contact position. The speed at which the coating head passes through the pressing means during sliding wiping was set to 20 mm / s.

Under this condition, the substrate is coated, and after 30000 coatings and cleanings are repeated, 20 random ejection holes are selected for the ejection holes of the coating head 6, and the maximum depth of the scratches generated around them is measured with a laser microscope. The average value measured with (VK-9700 manufactured by Keyence Corporation) was 1.9 μm. In the case of applying a phosphor paste for a plasma display, generally, if a scratch having an average depth of 3 μm or more occurs around the discharge hole, poor coating occurs frequently. However, in this embodiment, since the scratch is shallow, the coating should be continued. I was able to.
Comparative Example Except that the transfer wiping was not performed and only the sliding wiping was performed, wiping was performed under the same conditions as in the example, and application and cleaning were repeated in the same manner as in the example. From the point where about 10,000 sheets of coating were applied, streaky defects and defective coating with spreading of the phosphor paste that had not been applied spread to a part of the substrate at a considerable frequency. It was. At this time, when the depth of the flaw around the discharge hole 1 of the coating head was randomly measured with a laser microscope, the average flaw depth was 3.6 μm, exceeding the use limit of 3 μm.

  It is most suitable for manufacturing thin displays such as plasma displays or liquid crystal displays. The present invention is preferably applied to a high-viscosity paste containing solid particles at a high concentration, but can also be applied to a low-viscosity liquid such as an ink jet.

It is a schematic diagram which shows the mode of the crack generation | occurrence | production around the discharge hole of a coating head. It is the schematic which shows the cross section of the cleaning apparatus in this invention. It is the schematic diagram which showed 1st Embodiment of the coating head cleaning method of this invention. It is the schematic diagram which showed 2nd Embodiment of the coating head cleaning method of this invention. It is 3rd Embodiment of the coating head cleaning method of this invention using a washing | cleaning liquid. It is the schematic diagram which showed the example of the conventional coating head cleaning method. It is the schematic diagram which showed the other example of the conventional method application head cleaning method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge hole 2 Wiping off wound 3 Discharge surface 4 Cleaning apparatus cross section 5 Frame 6 Coating head 7 Wiping member 8 Coating head advancing direction (sliding wiping)
DESCRIPTION OF SYMBOLS 9 Elastic body 10 Winding apparatus 11 Unwinding apparatus 12 Elastic body 13 Adhesive paste 14 Gas inflow port 15 Phosphor paste 16 Pressing member 17 Pressing member 18 Contact position 19 Cylindrical surface uppermost 20 Second contact position 21 Cleaning liquid 22 Transfer paste 23 Paste after wiping 24 Scraper 25 Residual cleaning liquid 26 Scraper traveling direction

Claims (3)

A coating head cleaning method for cleaning a coating liquid adhering to and around a discharge hole of a coating head in which a plurality of discharge holes are arranged in a line, and the periphery of the discharge hole of the coating head is supported by a pressing member Holding for a predetermined time in contact with the wiping member, separating the coating head from the wiping member and transferring the coating liquid to the wiping member, and then supporting the coating head around the discharge hole with a pressing member A coating head cleaning method, wherein the coating head and the wiping member are moved relative to each other in one direction in a state where the wiping member is in contact, and sliding wiping is performed. The wiping member is supported by a pressing member having a cylindrical surface to perform the sliding wiping, and during the relative movement, the wiping member supported at the uppermost position of the cylindrical surface of the pressing member is discharged from the coating head. The coating head cleaning method according to claim 1, wherein the coating head passes through the hole. The wiping member is supported by a pressing member having a cylindrical surface whose center axis is parallel to the arrangement direction of the discharge holes of the coating head, and the coating head discharges the wiping member supported at a position other than the uppermost position of the cylindrical surface. Hold the periphery of the hole in contact for a predetermined period of time, separate the coating head and the wiping member, transfer the coating liquid to the wiping member, and then transfer the coating liquid of the wiping member supported by the same cylindrical surface 3. The coating head cleaning method according to claim 1, wherein sliding wiping is performed using a wiping member other than the part that has been removed.

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