JP2014172015A - Cleaning method of coating head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method of a coating head which can efficiently and securely clean paste adhered on a discharge port of the coating head and a discharge surface having the discharge port by using an adhesive tape.SOLUTION: A cleaning method of a coating head removes a coating liquid adhered on a discharge port of the coating head having a plurality of discharge ports arranged on a line approximately, and a discharge surface in a periphery of the discharge port with an adhesive tape. The method includes: a pressing process of pressing the discharge surface of the coating head to the adhesive tape and a pressing member which supports the tape from a non-adhesive surface, and contact-pressing the adhesive tape to the discharge surface; and a peeling process of peeling the adhesive tape from the discharge surface. When an alignment direction of the discharge ports is a Y-direction, a direction vertical to the discharge surface is a Z-direction, and a direction vertical to the Y-direction and the Z-direction is an X-direction, a form, that tension of the adhesive tape contacting with the discharge surface is asymmetric to a bisector H in an X-direction cross section of the discharge surface in the peeling process, is included in the method.

Description

  The present invention relates to a coating head cleaning method.

  In recent years, the spread of thin displays such as liquid crystal displays has increased. Many of these are so-called pixels in which a large number of small pixels are formed and an image is formed by electrically controlling the color and brightness of each pixel. Type display. An AC type plasma display can be given as an example of such a display.

  In the plasma display, a structure having various functions such as pixel partitioning is formed. The structure is called a barrier rib, and is provided in order to suppress the spread of the discharge to a certain region and perform display in a prescribed cell, and at the same time, ensure a uniform discharge space. 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 as a phosphor paste mainly composed of phosphor powder, an organic binder and an organic solvent, and is applied between predetermined barrier ribs and dried. 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, as shown in FIGS. 1 and 3, a coating head 1 having a space for storing the phosphor paste 2 inside is disposed so as to face a substrate 3 that is a member to be coated. The phosphor paste 2 is discharged from the discharge port 5 by introducing the compressed air whose pressure is controlled through the pressure pipe 4 connected to the space while relatively moving the discharge surface 6 and the substrate 3 with a predetermined clearance. This is a method of discharging and applying a paste between the partition walls 24.

In many cases, as a device for performing coating, a coating device including a stage having three axes of the X axis, the Y axis, and the Z axis is used, and the coating liquid is discharged from the discharge port while relatively moving the substrate and the coating head. As a result, the surface layer is formed on the substrate surface.
The application of the phosphor paste by the dispenser method is often a single-wafer intermittent application, and there are a discharge start and a discharge end while a single substrate is applied. In particular, the application start portion is a discharge start portion, and it is important that the discharge of the paste from the application head is stable with good reproducibility at the start of each application. For this purpose, as shown in FIG. 2A, it is important that the discharge surface before the start of application, particularly the periphery of the discharge port, is cleaned.

  On the other hand, the paste adheres to the discharge surface after the application due to the influence of the ballast effect when the paste is discharged or the paste connected at the clearance between the discharge surface and the substrate when the application is completed. Resulting in. That is, when the application to one substrate is completed after such application head completes application to one substrate, as shown in FIG. 2B, a part of the application liquid is discharged. In most cases, it is in the form of droplets adhering to and remaining on the periphery of the outlet. Here, if application is performed on the next substrate while the paste remains on the discharge surface 6 around the discharge port 5, various problems such as variations in the discharge amount at the application start portion and disturbance in the discharge behavior of the paste occur. Since the coating becomes unstable, the coating quality of the substrate is greatly impaired, and defective products are generated.

  Therefore, in such a mass production line for substrates, residual paste adhering to the discharge surface is removed within a predetermined tact time within a short period of time when application is intermittently stopped until application to the next substrate is resumed. If it is not cleaned, the coating quality of the next substrate will be greatly impaired.

  Therefore, every time a coating operation on a single substrate is completed, the coating liquid that has become an adhesion coating liquid is removed in a short time to clean the discharge surface of the coating head. Since this is an important production technique and affects both the improvement of functions of a final product including a substrate, such as a display device, and the improvement of cost competitiveness, many cleaning techniques have been developed.

  As a coating head cleaning technique, as shown in FIGS. 13A and 13B, an adhesive tape 104 having a solvent absorption capability is held in contact with the discharge surface of the coating head 1 to which the phosphor paste is adhered, and a residual paste. As shown in FIGS. 13C and 13D, the adhesive tape is peeled off substantially perpendicularly from the surface of the material to be cleaned, while the solvent component is absorbed from the adhesive paste. A technique for transferring to and cleaning is known (Patent Documents 1 and 2).

International Publication No. W02008 / 149758 JP 2012-205977 A

  However, the cleaning by simply peeling off the conventional adhesive tape almost perpendicularly selects the cleaning conditions such as the number of times of pressing to the adhesive tape and the pressing time as appropriate. Depending on a wide variety of coating liquids, poor cleaning may occur. For this reason, in the cleaning method using an adhesive tape, the present condition is that establishment of a cleaning technique that further improves the cleanliness is required.

  Accordingly, the present invention provides a coating head cleaning method capable of efficiently and reliably cleaning the paste adhering to the ejection port of the coating head and the ejection surface provided with the ejection port using an adhesive tape. For the purpose.

  Therefore, in the cleaning method of the coating head using an adhesive tape, the present inventors need to quickly remove the tape from the surface of the material to be cleaned. Has been found to be effective in improving

  That is, the present invention is a coating head cleaning method for removing a coating liquid adhering to a discharge port of a coating head having a plurality of discharge ports arranged in substantially one row and a discharge surface in the vicinity of the discharge port with an adhesive tape. A pressing step of pressing the pressure-sensitive adhesive tape against the pressure-sensitive adhesive tape and a pressing member that supports the tape from the non-sticky surface and pressing the pressure-sensitive adhesive tape against the discharge surface; and peeling the pressure-sensitive adhesive tape from the discharge surface; A separation step, wherein the discharge port array direction is the Y direction, the direction perpendicular to the discharge surface is the Z direction, and the Y direction and the direction perpendicular to the Z direction are the X direction, There is provided a coating head cleaning method characterized in that the tension of the adhesive tape in contact with the discharge surface in the peeling step includes an asymmetric shape with respect to the equidistant line H in the X-direction cross section of the discharge surface. To.

  According to the coating head cleaning method of the present invention, the tension of the adhesive tape in contact with the ejection surface becomes asymmetric with respect to the equidistant line H in the X-direction cross section of the ejection surface. Since the coating liquid can be peeled off from the ejection surface and the coating liquid remaining on the ejection port and ejection surface of the coating head can be surely removed, the occurrence of coating defects can be suppressed and the productivity can be improved.

It is the schematic diagram which showed the fluorescent substance paste coating method by the dispenser method. It is the schematic diagram which showed the adhesion state of the residual paste of the discharge port vicinity. It is the cross-sectional schematic diagram which showed the state of the coating head and the residual paste. It is a schematic diagram which shows the equivalent line H in the X direction cross section of the coating head discharge surface. It is the isometric view schematic diagram which showed the fluorescent substance paste coating device by the dispenser method. It is the side surface schematic diagram which showed the fluorescent substance paste coating device by the dispenser method. It is the schematic diagram which showed one Embodiment of the coating head cleaning method in this invention. It is the cross-sectional schematic diagram which showed one Embodiment of the pressing member which implement | achieves the coating head cleaning method in this invention. It is the cross-sectional schematic diagram which showed one Embodiment of the pressing member which implement | achieves the coating head cleaning method in this invention. It is the schematic diagram which showed 1st Embodiment of the coating head cleaning method in this invention. It is the schematic diagram which showed 2nd Embodiment of the coating head cleaning method in this invention. It is the schematic diagram which showed 3rd Embodiment of the coating head cleaning method in this invention. It is the schematic diagram which showed one Embodiment of the conventional coating head cleaning method. It is the schematic diagram which showed the aspect from which the adhesive tape of a discharge surface peeled by the coating head cleaning method in this invention.

  The coating head cleaning method of the present invention is a coating head cleaning method that removes the coating liquid adhering to the discharge port of the coating head having a plurality of discharge ports arranged in substantially one row and the discharge surface near the discharge port with an adhesive tape. A pressing step in which the discharge surface of the coating head is pressed against the pressure-sensitive adhesive tape and a pressing member that supports the pressure-sensitive adhesive tape from its non-stick surface, and the pressure-sensitive adhesive tape is brought into contact with the discharge surface; Peeling from the surface, and a step of arranging the discharge ports in the Y direction, the direction perpendicular to the discharge surface in the Z direction, the Y direction and the direction perpendicular to the Z direction in the X direction, In this case, the tension of the adhesive tape that is in contact with the discharge surface in the peeling step includes a form that is asymmetric with respect to the equidistant line H in the X-direction cross section of the discharge surface.

  Here, the coating head refers to a member having a discharge port for discharging a coating liquid, which is a member such as a coating nozzle or a base constituting the coating apparatus. The discharge port refers to an opening through which the coating liquid supplied to the coating head is discharged toward the object to be coated. Further, the discharge surface refers to a surface including the periphery of the discharge port on the outer surface of the coating head, that is, a surface where the discharge port opens. Further, the vicinity of the discharge port is a region near the outer edge of the discharge port. If the coating liquid remains applied in this region, the coating quality is significantly impaired.

  Moreover, the tension | tensile_strength of the adhesive tape which is in contact with the discharge surface means the force which peels off an adhesive tape from a discharge surface. This force makes it possible to peel the adhesive tape from the discharge surface and remove the coating liquid.

  Further, the equipartition line H in the X-direction cross section of the ejection surface represents the center line of the width of the ejection surface 6 in the X direction (see, for example, FIG. 4). According to the coating head cleaning method of the present invention, the tension of the pressure-sensitive adhesive tape in contact with the discharge surface is asymmetric with respect to the equidistant line H in the X-direction cross section of the discharge surface, Therefore, the adhesive tape can be quickly removed in a short time.

Examples of the coating liquid that adheres to the discharge port include a phosphor paste, a reflective layer paste, a dielectric paste, or an electrode paste used for manufacturing a plasma display panel (hereinafter, “PDP”). The invention is preferable when the paste viscosity is 10 to 100 Pa · s, and more preferable when the paste viscosity is 20 to 70 Pa · s. When the paste viscosity is less than 10 Pa · s, the paste easily oozes out from the application head when it is not applied, and the amount of adhesion increases, and wiping residue tends to occur. On the other hand, if it is greater than 100 Pa · s, it becomes difficult to discharge due to high viscosity, and it is difficult to increase the coating speed. The paste viscosity can be measured using a Brookfield viscometer at a measurement temperature of 25 ° C. and a shear rate of 2.4 s ⁻¹ .

  Furthermore, the present invention is particularly suitable when the coating head is a PDP phosphor coating head and the coating liquid is a PDP phosphor paste. In the single-wafer coating method in which the coating is started and finished for each surface, the ejection surface was not sufficiently cleaned or a wiping wound occurred. Since the discharge surface can be cleaned without causing scratches, a very uniform and high-quality coated surface can be obtained. Accordingly, a coating head cleaning method in the case of applying a PDP phosphor paste using a PDP manufacturing phosphor coating nozzle will be described in detail below with reference to the drawings, but the present invention is not limited thereto. It is not a thing.

  First, an example of the overall configuration of the PDP phosphor coating apparatus will be briefly described.

  FIG. 5 is an overall perspective view of an example of a PDP phosphor coating apparatus, and FIG. 6 is a side view thereof.

  The apparatus shown in FIG. 5 is provided with a pair of X-direction guide rails 16 on a base 15, and a portal type with an application head so that the guide guides 17 on the guide rails 16 travel linearly. A frame (gantry) 18 is installed. Further, a table 19 is installed between the guide rails 16. A plurality of suction holes or suction grooves (not shown) are provided on the upper surface of the table 19 so that the substrate 20 can be fixed to the upper surface of the table 19 by vacuum suction. The substrate 20 moves up and down on the table 19 by lift pins (not shown). Alternatively, a roller capable of transporting the substrate may be built in the table 19 and the substrate 20 may be raised and lowered by raising and lowering the roller. The pair of guide rails 16 are provided with a drive system (not shown) that drives the entire gantry 18. The gantry 18 can reciprocate on the guide rail 16 in the X-axis direction by these drive systems.

  The table 19 includes a Y-direction moving mechanism 22 and can operate in a direction perpendicular to the X direction. In addition, a rotation mechanism (not shown) is included, and the table 19 itself can rotate (θ direction) in the XY plane.

  The gantry 18 has a pair of Z axes 25 operable in a direction perpendicular to the substrate mounting surface of the table 19, and a coating head 1 for discharging a coating liquid is attached to a holder 23 associated with the Z axis. It has been. The longitudinal direction of the coating head 1 is arranged to coincide with the width direction of the substrate 20.

  With these configurations, the coating head 1 can be freely moved in the X-axis and Z-axis directions. Along with the Y-direction moving mechanism 22 provided in the table 19, the coating head, the table, and the substrate are configured to be relatively movable in the XYZ3 directions.

  The coating head 1 extends horizontally in the direction perpendicular to the reciprocating direction of the gantry 18, that is, in the Y-axis direction, but can be kept parallel to the substrate 20 and the table 19 by individual operation of the Z-axis 25. Become. The discharge head of the coating head may be single or plural, and may have any shape such as a slit, a circle, an ellipse, or a polygon, but the coating head is a PDP phosphor coating head. In such a case, the number of the phosphor pastes necessary for one screen in the PDP can be applied by at least one ejection for each color (about 1000 to 4000) according to the number of pixels in the scanning direction. It is preferable that the discharge ports (diameter of about 50 to 200 μm, in some cases may be oval or polygonal) are arranged in a straight line in the longitudinal direction of the coating head. The arrangement positions of the discharge ports may be arranged on a straight line in the X-direction cross section of the discharge surface 6 or may be formed at a position away from the equal line. In view of processing restrictions, application restrictions, etc., it is preferable to arrange them at suitable positions.

  On the base 15, there is a coating head cleaning device 26. The coating head cleaning device 26 is installed so as to be positioned between the guide rails 16, and the gantry 18 moves to the position of the coating head cleaning device 26 and cleans the coating head 1 at that position.

  Next, an example of the configuration of the coating head cleaning device for realizing the coating head cleaning of the present invention will be described. FIG. 7 is a schematic view showing an embodiment of a coating head cleaning device.

  The coating head cleaning device 26 includes a transfer cleaning unit 100 that performs cleaning by pressing / peeling to the adhesive tape. The structure of the transfer cleaning unit 100 includes unwinding means for intermittently supplying the adhesive tape unwound from the roll, winding means for winding the cleaned adhesive tape into a roll, and tension of the adhesive tape. It is preferable to have a means for controlling and a means for controlling the feed amount of the adhesive tape.

  In the transfer cleaning unit 100, the unwinding adhesive roll 101 that unwinds the adhesive tape 104 that is a consumable member for transfer and the non-adhesive surface of the unrolled adhesive tape 104 are in partial contact, and the adhesive surface of the adhesive tape 104 is removed. A transfer pressing member 103, which is an elastic body that is pressed against the discharge surface of the coating head, that is, an elastic body, and a winding adhesive roll 102 that winds the adhesive tape 104 are provided. Here, the installation position of the transfer pressing member 103 is the coating head pressing position, and the discharge surface 6 of the coating head 1 is pressed against the adhesive surface of the adhesive tape 104 on the transfer pressing member 103. As this transfer pressing member 103, a member that wraps a fixed transfer pressing member core portion 105 with an elastic body 106 and that is in contact with the ejection surface 6 of the coating head 1 at the time of transfer is cylindrical or arcuate is used. Is preferred.

  The pressing may be performed by driving the transfer cleaning unit 100 up and down in the Z direction. However, for simplification of the configuration, it may be performed by moving up and down the coating head 1 using the Z axis of the coating device. . The elastic body 106 is suitable to have an appropriate hardness and generate an appropriate pressure between the adhesive tape 104 and the nozzle when pressed.

  Various materials can be used as the elastic body constituting the support portion of the pressing member. However, rubber is preferable, and rubber that does not suffer damage such as residual strain even when repeatedly pressed, and that recovers quickly is more preferable. Examples of such rubber include silicon rubber and natural rubber. In addition, a rubber material that does not easily deteriorate even if a paste is attached is preferable. However, when such a rubber material cannot be selected, a cover film or the like may be provided on the rubber surface.

  The hardness of the rubber used as the elastic body is preferably A20 to A60 degrees (JIS K 6253 (2006)), more preferably A30 to A40 degrees. When the hardness of the rubber is less than A20 degrees, the pressing pressure tends to be insufficient and transfer defects tend to occur. On the other hand, if it is larger than A60 degrees, the elasticity is impaired and a uniform pressing pressure cannot be obtained, and the coating head is liable to be damaged. The variation in the hardness of the rubber on the pressing member contact surface is preferably 20 degrees or less and more preferably 10 degrees or less in order to obtain a uniform pressing pressure.

  As for the shape accuracy of the transfer pressing member, in order to obtain a uniform pressing pressure, the straightness of the contact surface of the pressing member with the coating head is preferably 1 mm or less, and preferably 0.5 mm or less. More preferably, it is more preferably 0.2 mm or less. Further, the surface roughness of the abutting surface of the pressing member is preferably 0.2 mm or less, and more preferably 0.1 mm or less in order to obtain a uniform contact pressure.

  1-30 mm is preferable and, as for the thickness of the rubber | gum used as an elastic body, 5-15 mm is more preferable. If the rubber thickness is less than 1 mm, the elasticity is impaired and an appropriate pressing pressure cannot be obtained. On the other hand, if it is larger than 30 mm, unnecessary materials increase and the apparatus becomes large, which is uneconomical.

  The cross-sectional shape of the abutting surface of the pressing member is preferably a convex shape that can surely perform contact pressure on the particularly important discharge surface because a portion where the contact pressure is insufficient is likely to occur in a flat or concave shape, More preferably, the shape of the contact surface is part of a cylinder. That is, the pressing member preferably includes an elastic body having a cylindrical cross section in the X direction.

  In this case, if the discharge port is pressed against the top of the cylinder, the contact pressure starts near the discharge ports arranged in a line and then expands to the periphery of the discharge port, so that the spread of the paste is made uniform when pressed. Therefore, it is preferable. That is, it is preferable that the substantially vertex of the cross section in the X direction of the cylindrical elastic body is brought into contact with the plurality of discharge ports arranged in a line through the adhesive tape.

  In some cases, it is also preferable to use a pressing member whose cross-sectional shape is asymmetric with respect to the cross-sectional center as shown in FIG. That is, it is also preferable that the X-direction cross-sectional shape of the pressing member is asymmetric with respect to the cross-sectional center. In this case, the pressure of the pressure-sensitive adhesive tape in close contact with the discharge surface via the pressing member is maintained in the X direction of the discharge surface while maintaining the pressing pressure in the vicinity of the discharge port to which the paste to be removed is adhered in the same manner as the cylindrical shape. As a result of the cross-section being asymmetric, the peeling direction in the peeling step, which is a subsequent process, becomes the cross-sectional direction of the discharge surface, and thus the adhesive tape can be quickly peeled off in a short time.

  In some cases, it is also preferable to use a pressing member having different elastic body hardness as shown in FIG. That is, it is also preferable that the hardness of the elastic body of the pressing member is asymmetric with respect to the X-direction cross-sectional center. In this case, while maintaining the pressing pressure in the vicinity of the discharge port to which the paste to be removed is adhered in the same manner as the pressing member having a constant hardness, the appearance of the adhesive tape that adheres to the discharging surface through the pressing member is As a result, the pressure-sensitive adhesive tape can be quickly peeled off in a short time because the peeling direction in the peeling process, which is a subsequent process, becomes the cross-sectional direction of the discharge surface.

  Further, even when the ejection head 1 is pressed against the position away from the top of the cylinder in the X direction as shown in FIG. 3, the spread of the paste is made uniform in the X direction and the adhesive tape to the ejection surface Is asymmetric with respect to the equipartition line H seen from the X-direction cross section of the discharge surface, and the peeling direction in the subsequent adhesive tape peeling step is preferably the cross-sectional direction of the discharge surface. That is, it is also preferable that the equipartition line H and the substantially vertex in the X direction cross section of the elastic body do not coincide with each other in the X direction. In this case, it is more preferable that the equidistant line H and the approximate vertex of the X-direction cross section of the elastic body are separated by 1 mm or more in the X direction.

  In addition, it is preferable that the shape of the contact surface is a part of a cylinder because the processing of the contact surface is facilitated, and as a result, the straightness is improved.

  The diameter of the cylinder is preferably 10 to 1000 mm, and more preferably 20 to 100 mm. When the diameter of the cylinder is less than 10 mm, an appropriate pressure is not uniformly applied to the discharge surface. On the other hand, if it is larger than 1000 mm, the convex effect is weakened, and a portion with insufficient pressing pressure tends to occur.

  The pressing pressure is preferably 0.01 to 1 MPa, and more preferably 0.05 to 0.3 MPa. When the pressing pressure is less than 0.01 MPa, the transfer of the paste becomes non-uniform. On the other hand, when the pressure is larger than 1 MPa, a great load is generated on the contact pressure mechanism, and the coating head is easily damaged. For the measurement of the pressing pressure, for example, a pressure sensitive sheet (trade name: Prescale) manufactured by Fuji Photo Film Co., Ltd. is used. Alternatively, a contact pressure sensor may be installed in combination with the pressing member, and the measurement result of the pressing pressure may be fed back to the controller for the contact pressure operation to obtain a uniform pressing pressure.

  Such a pressing pressure can be suitably realized particularly when the pressing amount of the coating head to the transfer pressing member is 0 mm to 5 mm. When the pressing amount is larger than 5 mm, the coating head is liable to be damaged, and a great load is generated on the contact mechanism.

  The unwinding adhesive roll 101 and the winding adhesive roll 102 are driven by an unwinding motor 109 and a winding motor 110 via a drive transmission mechanism (not shown), and unwinding and winding of the adhesive tape 104 are performed. It is preferable to set the unwinding amount for each transfer cleaning of the adhesive tape 104 from the unwinding adhesive roll 101 while saving the amount of the adhesive tape used so that the number of wiping operations can be increased. For example, when the discharge surface width of the coating head is 4 to 16 mm, it is preferably 2 to 8 mm. The unwinding amount is desirably controlled by, for example, measuring the diameter of the winding adhesive roll 102 with a roll diameter detection sensor (not shown), and driving speed and driving time of the winding adhesive roll 102 calculated from the diameter. Further, the tension is always applied to the adhesive tape 104 so that the adhesive tape 104 is not wrinkled on the transfer pressing member 103. Therefore, (i) winding the adhesive tape 104 with the winding adhesive roll 102 while controlling the torque of the unwinding motor 109 so as to generate a braking force. (Ii) When stopping other than unwinding the adhesive tape 104, It is preferable to apply tension to the adhesive tape 104 by the take-out motor 109.

  The pressure-sensitive adhesive tape used in the coating head cleaning method of the present invention may be appropriately selected according to the type of coating liquid and the amount of adhesion, but is preferably composed of a substrate and a pressure-sensitive adhesive layer. More preferably, it consists of a solvent-absorbing adhesive. This is because when the adhesive absorbs the paste or paste solvent, the fluidity of the paste decreases (solidifies), and it becomes easy to peel and transfer. For this purpose, the solubility parameter of the pressure-sensitive adhesive is preferably close to that of the paste or paste solvent.

The solvent absorption capacity of the adhesive tape is preferably 10 mL or more, more preferably 20 mL or more per 1 m ² area. When the solvent absorption capacity is less than 10 mL per 1 m ² , the solvent absorption residue tends to occur. Here, the solvent absorption capacity of the pressure-sensitive adhesive tape refers to a value calculated from the weight increased by absorption after the pressure-sensitive adhesive tape is immersed in the solvent constituting the coating liquid for 1 minute.

The solvent absorption rate of the pressure-sensitive adhesive tape is preferably 1 mL / second or more, more preferably 3 mL / second or more per 1 m ^{2 of} area. If the solvent absorption rate is less than 1 mL / ^second per area of 1 m ² , paste solvent absorption takes too much time and the time required for cleaning tends to increase. Here, the solvent absorption rate of the pressure-sensitive adhesive tape refers to a value calculated by immersing the pressure-sensitive adhesive tape in a solvent constituting the coating solution for 5 seconds, and then reverting the weight increased by absorption per unit area per unit time. .

  The adhesive strength of the adhesive tape is preferably 0.5 to 4.0 N per 20 mm width, and more preferably 2.0 to 3.0 N. If the adhesive force per 20 mm width is less than 0.5 N, the solidified product remaining after absorbing the solvent in the paste remaining on the ejection surface tends to be unable to be removed. On the other hand, when it is larger than 4.0 N, it takes time to peel off the pressure-sensitive adhesive tape, and the pressure-sensitive adhesive layer tends to peel from the base material of the pressure-sensitive adhesive tape. The adhesive strength of the adhesive tape is a method based on JIS Z 0237 (2000), and a 25 μm thick PET film and an adhesive tape are bonded together and pulled in the 180 ° direction at 23 ° C. and a pulling speed of 300 mm / min. The value measured after peeling. In addition, it is important that an adhesive tape has adhesive force even after solvent absorption.

  The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is preferably 0.005 to 0.3 mm, and more preferably 0.01 to 0.15 mm. There exists a tendency which cannot fully absorb the solvent in a paste as the thickness of an adhesive layer is less than 0.005 mm. On the other hand, if the thickness is larger than 0.3 mm, the winding length is shortened because the adhesive tape is thick, the usage time of the adhesive tape is shortened, and roll replacement tends to be frequent.

  The tension of the pressure-sensitive adhesive tape before contact with the ejection surface of the coating head is preferably 10 to 1000 N / m, more preferably 30 to 200 N / m. When the tension is less than 10 N / m, the conveyance of the adhesive tape becomes unstable, and meandering and wrinkling occur. On the other hand, if it is larger than 1000 N / m, the driving equipment for applying high tension becomes large or the load on the apparatus increases. More preferably, it is 30 to 200 N / m.

  In addition to the installation of various known wrinkle-stretching means in the coating head cleaning device, it is preferable to install means for preventing charging, particularly in the adhesive tape, but it is easy to prevent discharge and to prevent adsorption of dust. Therefore, the charge amount of the adhesive tape is preferably 10 kV or less, and more preferably 1 kV or less.

  In the coating head cleaning method of the present invention, it is preferable that the transfer cleaning unit 100 be a detachable cassette type as shown in FIG. In the case of the cassette type, it is possible to efficiently perform work such as replacement of a sticky roll that has been used. In addition, if a spare cassette is prepared, the roll replacement operation is completed by replacing the cassette, so that the roll can be replaced in a shorter time.

  FIG. 10, FIG. 11 and FIG. 12 show examples of operation modes of the coating head and the like in the coating head cleaning method of the present invention. This will be described in order below.

  FIG. 10 is a first embodiment showing the coating head cleaning method of the present invention. (A) After application, the discharge surface with the paste adhering around the discharge port is pressed against (b) the adhesive tape and held for an appropriate period of time, and (c) the application head is moved to a height at which the adhesive tape does not peel from the discharge surface. Raise in the Z direction. Again, at this point in time, the adhesive tape has not peeled from the discharge surface. Thereafter, (d) an application head is moved in the X direction. In (c), instead of raising the coating head in the Z direction, the coating head cleaning device 26 including the transfer pressing member 103 may be lowered in the Z direction. In (d), Instead of moving the coating head in the X direction, the coating head cleaning device 26 may be moved in the X direction. By doing so, it is possible to quickly peel the adhesive tape from the discharge surface, which is preferable because it improves cleanliness. That is, it is preferable to move the coating head or the coating head cleaning device relative to the X direction after moving the coating head or the coating head cleaning device in the peeling direction corresponding to the above (c) and (d).

  In the coating head cleaning method of the present invention, FIG. 14 shows a schematic diagram in which the adhesive tape is peeled off from the ejection surface. In FIG. 14, the tension to peel off the adhesive tape 104 in contact with the discharge surface is asymmetric with respect to the equidistant line H in the X-direction cross section of the discharge surface, and the direction of peeling the adhesive tape is the X direction of the discharge surface. It becomes the behavior of the direction. Since the width of the discharge surface in the X direction is narrow, it is preferable because this makes it possible to stably and more quickly peel the adhesive tape from the discharge surface.

  The upward movement distance of the coating head in the Z direction is (i) that the pressing pressure between the pressing member and the coating head discharge surface is 0 MPa, and (ii) that there is no hindrance to the subsequent movement in the X direction (physical If the distance satisfies at least the conditions such as interference) and (iii) that the adhesive tape does not peel from the discharge surface, it is preferably set as appropriate according to the situation.

  The movement of the coating head in the Z direction is a slight distance movement in which the adhesive tape does not peel from the ejection surface, so that a speed of at least 10 mm / s or more is sufficient.

The movement of the coating head in the X direction is preferably performed at a speed of at least 10 mm / s and an acceleration of 50 mm / s ^ ² or more in order to quickly peel off the adhesive tape.

FIG. 11 is a second embodiment showing the coating head cleaning method of the present invention. As in FIG. 10, (a) the discharge surface with the paste attached around the discharge port after application is pressed against (b) the adhesive tape and held for an appropriate period of time, and then the application head is placed as shown in (c) and (d). This is one embodiment in which it is raised in the Z direction and simultaneously moved in the X direction. Thereby, like the first embodiment, it is possible to quickly peel the adhesive tape from the discharge surface, which is preferable because it improves cleanliness. That is, it is preferable to simultaneously move the coating head or the coating head cleaning device in the Z direction and the X direction in the peeling step corresponding to the above (c) and (d). The moving speeds in the X direction and the Z direction are preferably 10 mm / s or more and acceleration 50 mm / s ^ ² .

  FIG. 12 is a third embodiment showing the coating head cleaning method of the present invention. (a) The discharge surface with the paste around the discharge port after application is pressed against (b) the adhesive tape, but the center of the discharge surface in the X direction is shifted from the approximate apex of the pressing member having a cylindrical cross section. It is what you press. By doing so, the adhesive state of the adhesive tape to the ejection surface becomes non-uniform at the center in the X direction of the ejection surface. And as shown in (c) and (d), it is one embodiment which moves a coating head to a Z direction after that. As a result, the adhesive tape attached to the discharge surface has a difference in tension between the left and right when viewed from the X-direction cross section when moving in the Z direction, resulting in an adhesive tape peeling behavior in the X direction as shown in FIG. Therefore, it is preferable.

  About each operation | movement mentioned above, it is preferable to program in the control system of a coating device beforehand as a normal operation sequence so that it can select suitably in view of the property etc. of the coating liquid to be used.

  Hereinafter, an example of cleaning the phosphor coating head for PDP will be described in detail with reference to examples and comparative examples, but the present invention is not limited thereto.

  As the coating liquid, phosphor pastes of red (R), blue (B), and green (G) were used. The respective viscosities were R phosphor paste: 52 Pa · s, B phosphor paste: 39 Pa · s, and G phosphor paste: 40 Pa · s.

(Configuration of coating device and cleaning device)
The coating head for applying the phosphor paste has 1920 discharge ports with a hole diameter of 100 μm arranged in the longitudinal direction of the coating head, and the discharge ports are arranged on the equipartition line in the X-direction section of the discharge surface. (See FIG. 3). Using this coating head, a pressure of 200 to 1000 kPa is applied to the inside by air, the clearance with the substrate is set to 200 μm, and the traveling speed with respect to the substrate is changed within the range of 20 to 200 mm / s to discharge the phosphor paste. Then, a phosphor paste was applied between predetermined barrier ribs. The substrate to be applied was a 42 inch size.

  Examples of the coating apparatus that applies using the coating head include a stage having an XYZθ4 axis, a control unit that controls and drives the XYZθ4 axis, and a storage control unit that controls the operation of the coating apparatus and the cleaning apparatus using a predetermined program. The coating apparatus comprised from this was used.

  As the cleaning device, a cleaning device including a transfer cleaning portion using an adhesive tape was used. This cleaning device used was a replaceable cassette type.

  As the adhesive tape, ELEP (registered trademark; manufactured by Nitto Denko Corporation) was used.

Example 1
The coating head was filled with phosphor paste and applied between predetermined partitions. Thereafter, a roll of adhesive tape was used to clean the application head in which the phosphor paste adhered to the discharge port and the discharge surface. As a transfer pressing member, a rubber roll (diameter 60 mm, rubber hardness A30, rubber thickness 10 mm) is installed so as to face the discharge surface of the coating head, and pressed at a position where the approximate vertex of the cylinder coincides with the arrangement position of the discharge ports. The operation was carried out.

  In this example, the pressing step and the peeling step were performed using the form of the schematic diagram shown in FIG. A tension of 4 kg / m was applied to the adhesive tape. Next, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is brought into contact with the discharge port and the discharge surface of the coating head after application, the discharge surface of the coating head is pressed into the pressing member by 2 mm and held for 4 seconds, and then the coating head is removed from the transfer pressing member. After moving 4 mm in the direction of separation (in this case, the adhesive tape was still in close contact with the ejection surface), the coating head was moved 30 mm in the X direction at 200 mm / s to remove the adhesive surface of the adhesive tape. I peeled off quickly. By this cleaning method, the paste around the discharge surface and the discharge port was removed.

  While this cleaning method was applied to 500 substrates, the coating could be applied without any deterioration in quality such as the occurrence of coating defects.

(Example 2)
In this example, the peeling process was performed using the form of the schematic diagram shown in FIG. 11, and the others were performed using the cleaning method described in Example 1. In the peeling step, the coating head is moved 20 mm at 50 mm / s in a direction away from the transfer pressing member, and at the same time, it is also moved 50 mm at 200 mm / s in the X direction to quickly peel off the adhesive surface of the adhesive tape from the ejection surface. . By this cleaning method, the paste around the discharge surface and the discharge port was removed.

  While this cleaning method was applied to 500 substrates, the coating could be applied without any deterioration in quality such as the occurrence of coating defects.

(Example 3)
In this example, the pressing step and the peeling step were performed using the form of the schematic diagram shown in FIG. 12, and the others were performed using the cleaning method described in Example 1. In the pressing process, the pressing operation is performed at a position where the approximate vertex of the rubber roll cylinder as the transfer pressing member is separated from the equipartition line in the X-direction cross section of the discharge surface (position in the arrangement direction of the discharge ports in this embodiment) by 4 mm. Carried out. In the peeling step, the coating head was moved at a speed of 50 mm / s in a direction away from the transfer pressing member, and the pressure-sensitive adhesive surface of the pressure-sensitive adhesive tape was quickly peeled off from the discharge surface. By this cleaning method, the paste around the discharge surface and the discharge port was removed.

  While this cleaning method was applied to 500 substrates, the coating could be applied without any deterioration in quality such as the occurrence of coating defects.

Example 4
In this embodiment, a member having a step as shown in FIG. 8 is used as the transfer pressing member, and the pressing step and the peeling step are performed at the position where the center of the X direction cross section of the pressing member and the discharge surface substantially coincide ( The cleaning method described in Example 3 was used except for the application of the schematic diagram shown in FIG. By this cleaning method, the paste around the discharge surface and the discharge port was removed.

  While this cleaning method was applied to 500 substrates, the coating could be applied without any deterioration in quality such as the occurrence of coating defects.

(Example 5)
In this example, the same cleaning method as that of Example 4 was used except that the transfer pressing member shown in FIG. 9 was used. By this cleaning method, the paste around the discharge surface and the discharge port was removed.

  While this cleaning method was applied to 500 substrates, the coating could be applied without any deterioration in quality such as the occurrence of coating defects.

(Comparative Example 1)
In this comparative example, the same cleaning method as in Example 1 was used except that the operation shown in FIG. 13 was used. By this cleaning method, 500 sheets were applied to the substrate while removing the paste around the discharge surface and the discharge port.

  As a result, a coating defect occurred on 32 sheets, and it was an abnormality of the coating start part considered to be caused by poor cleaning. In some cases, there was a slight amount of paste left on the discharge surface. Since this is considered to be the cause of the abnormality in the application start part, application using this cleaning method was interrupted.

  The present invention is suitable for manufacturing flat panel displays such as plasma displays and 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 coating liquid such as an ink jet.

DESCRIPTION OF SYMBOLS 1 Coating head 2 Phosphor paste 3 Substrate 4 Pressurized piping 5 Discharge port 6 Discharge surface 7 Phosphor paste 8 discharged Residual paste 15 Base 16 Guide rail 17 Guide guide 18 Portal frame (gantry)
19 Table 20 Substrate 21 Slide leg 22 Y-direction moving mechanism 23 Holder 24 Partition 25 Z-axis 26 Coating head cleaning device 100 Transfer cleaning unit 101 Unwinding adhesive roll 102 Winding adhesive roll 103 Transfer pressing member 104 Adhesive tape 105 Transfer pressing Member core portion 106 Elastic body 107 Transfer pressing member support portion 109 Unwinding motor 110 Rewinding motor

Claims (10)

It is a coating head cleaning method for removing the coating liquid adhering to the discharge port of the coating head having a plurality of discharge ports arranged in a substantially line and the discharge surface near the discharge port with an adhesive tape,
A pressing step of pressing the pressure-sensitive adhesive tape against the discharge surface by pressing the discharge surface of the coating head against the pressure-sensitive adhesive tape and a pressing member that supports the tape from the non-stick surface;
A peeling step for peeling the adhesive tape from the discharge surface,
In the case where the arrangement direction of the discharge ports is the Y direction, the direction perpendicular to the discharge surface is the Z direction, and the direction perpendicular to the Y direction and the Z direction is the X direction,
The coating head cleaning method characterized by including the form from which the tension | tensile_strength of the adhesive tape which is in contact with the said discharge surface at the said peeling process becomes asymmetric with respect to the equidistant line H in the X direction cross section of the said discharge surface.   The coating head cleaning method according to claim 1, wherein, in the peeling step, the coating head is moved in the X direction after being moved in the Z direction.   The coating head cleaning method according to claim 1, wherein in the peeling step, the coating head is moved simultaneously in the Z direction and the X direction.   The said pressing member is a coating head cleaning method as described in any one of Claims 1-3 provided with the elastic body whose cross section in the said X direction is cylindrical.   The application according to claim 4, wherein the pressing step is a step of bringing the substantially vertex in the X-direction cross section of the elastic body into contact with the plurality of discharge ports arranged in a substantially line through the adhesive tape. Head cleaning method.   5. The coating head cleaning method according to claim 4, wherein in the pressing step, the equipartition line H and a substantially vertex of the X-direction cross section of the elastic body do not coincide with each other in the X direction.   The coating head cleaning method according to claim 6, wherein the equipartition line H and the approximate apex of the cross section of the elastic body in the X direction are separated by 1 mm or more in the X direction.   The coating head cleaning method according to claim 1, wherein a cross-sectional shape in the X direction of the pressing member is asymmetric with respect to a center of the cross section.   The coating head cleaning method according to claim 1, wherein the hardness of the elastic body of the pressing member is asymmetric with respect to the center in the X-direction section.   The coating head cleaning method according to claim 1, wherein the coating liquid is a phosphor paste for a plasma display panel.

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