JP2009166014A - Head cleaning device, manufacturing apparatus of flat panel display, flat panel display, manufacturing apparatus of solar cell, solar cell, and head cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cope with two cleanings such as cleaning of ink which becomes a liquid film on an ink jet head, and cleaning of spacer beads in a dried and adhered state. <P>SOLUTION: A head cleaning device includes a suction mechanism 43 for sucking and removing a liquid film of ink adhered to an ink jet head 24 provided by arranging a plurality of nozzles 30 in a line for jetting ink including spacer beads downwardly in a non-contact manner, and a cleaning mechanism 42 for supplying a cleaning liquid to solidified stain containing the space beads adhered to the ink jet head 24 by drying ink. When the ink only becomes an adhered liquid film, the cleaning of removing the liquid film using the suction mechanism 43 which is finished in a short period of time is performed. When the ink becomes solidified stain, the cleaning by cleaning using the cleaning mechanism 42 for supplying the cleaning liquid of high cleaning effect is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a head cleaning device, a flat panel display manufacturing device, a flat panel display, a solar cell manufacturing device, and a cleaning device for cleaning a jet head having a plurality of jet ports for spraying a suspension in which particles are mixed. The present invention relates to a solar cell and an inkjet head cleaning method.

  One flat panel display is a liquid crystal display. The liquid crystal display is composed of a TFT substrate made of a transparent thin plate such as glass and a color filter substrate, and a minute gap called a cell gap is formed between the TFT substrate and the color filter substrate. The cell gap is secured by a spacer made of an aggregate of a plurality of spacer beads, and liquid crystal is sealed in this space. The spacer is composed of spherical fine particles having a particle diameter of 3 to 5 μm, and a large number of spacers are dispersed on either the TFT substrate or the color filter substrate.

  The spacer is limitedly arranged in the black matrix region on the substrate. For this purpose, spacer ink made of a suspension in which spacer beads are uniformly dispersed in a solvent is used to spray the spacer ink so as to land on the black matrix region. As a method for supplying the spacer ink, an ink jet method is adopted. In general, an ink jet method uses an ink jet head composed of an ink jet head in which a plurality of minute nozzles are arranged in a row and ejects droplets of spacer ink from each nozzle toward a substrate.

In the inkjet method, the inkjet head is periodically cleaned. As this type of cleaning technique, for example, there is a technique disclosed in Patent Document 1. In Patent Literature 1, a local suction unit that locally sucks and removes ink from each nozzle is provided, and the local suction unit is moved in the nozzle arrangement direction to clean each nozzle.
JP-A-5-201028

  When ink is repeatedly ejected from each nozzle of the inkjet head, a part of the ink becomes a liquid film and adheres to the inkjet head. Since the spacer beads are mixed in the ink and the liquid has a high viscosity, when the ink attached to the ink jet head is dried, the ink is evaporated and the spacer beads are solidified and fixed to the ink jet head. In addition, when ink is repeatedly ejected from each nozzle and new ink adheres to the solidified dirt fixed to the ink jet head, the solidified dirt accumulates and the solidified dirt grows as a lump. When this solidified soil lump grows and closes a part of the nozzle, the direction of the ink ejected from each nozzle is curved in a direction different from the original direction, and the ink is landed at a predetermined position on the substrate. I can't. Further, when the entire surface of the nozzle is closed, ink cannot be ejected from each nozzle, and ink is not ejected.

  In this regard, in the technique of Patent Document 1, since the local suction is performed on the nozzle, the spacer is firmly fixed to the inkjet head after the ink is dried, regardless of the state of the liquid film before the ink is dried. Not suitable for removal of beads.

  Accordingly, the present invention is directed to cleaning a suspension of ink or the like in a liquid film state on an ejection head such as an ink jet head, and cleaning of solidified dirt such as spacer beads in a state where the suspension is dried and fixed. It aims at responding to two cleanings.

  According to a first aspect of the present invention, there is provided a head cleaning device in a non-contact manner with a liquid film of a suspension adhering to an ejection head provided with a plurality of ejection openings arranged in a row for ejecting the suspension downward. A liquid film removing means for removing by suction, and a cleaning means for supplying the cleaning liquid to the solidified soil containing the particles in the suspension dried and fixed to the ejection head for cleaning. It is characterized by.

  According to the head cleaning device of the first aspect, the liquid cleaning device includes two means, that is, a liquid film removing means and a cleaning means. The liquid film is removed from the suspension and the solidified dirt containing particles mixed in the suspension is provided. It is possible to correspond to two cleanings, i.e., cleaning. The liquid film is removed by the liquid film removing means if the suspension is attached to the ejection head as a liquid film, and if it is solidified dirt, the washing means is used for cleaning. . Thus, depending on the state of the ejection head, cleaning can be performed by freely selecting one of the two cleaning units, and cleaning can be performed in combination.

  As the ejection head, an inkjet head that scatters spacer beads for forming a cell gap can be applied when manufacturing a flat panel display such as a liquid crystal display. In the case of an inkjet head, the suspension is an ink in which spacer beads dispersed and arranged in the black matrix region are mixed. Further, the ejection head can be applied to other uses, for example, when a solar cell is manufactured. In a solar cell, a metal wiring and a metal film for taking out the generated electricity in the panel cell to the outside, a silicon film for converting sunlight into electricity, ITO (transparent conductive film), and the like are formed on a glass substrate. At this time, metal particles in nano units can be mixed in the suspension, and the suspension can be ejected from the ejection head to form a metal film on the glass substrate, draw a metal wiring, or the like. Therefore, the present invention can be applied when cleaning an ejection head provided in a manufacturing apparatus for manufacturing a solar cell.

  The cleaning liquid supplied by the cleaning means may be a dedicated cleaning liquid (such as isopropyl alcohol or ethylene glycol) that causes a high peeling force to act on the solidified dirt, but the same type of cleaning liquid as the suspension (spacer beads or metal) It is desirable to use a suspension in which particles and the like are not mixed.

  Here, the cleaning by the liquid film removing means is cleaning that removes the liquid film adhering to the ejection head in a non-contact manner, and thus the cleaning operation is completed in a relatively short time. On the other hand, the cleaning by the cleaning means is cleaning for supplying the cleaning liquid to remove the solidified dirt, and therefore requires more work time than the cleaning by the liquid film removing means. Moreover, it is sufficient to always remove the liquid film of the suspension by the liquid film removing means. However, if the number of sprays increases, it is necessary to remove the solidified dirt. Therefore, if the liquid film removing means having a short working time and the cleaning means for removing the solidified dirt are used in combination, the two effects of high cleaning effect and shortening of the cleaning time can be achieved in a balanced manner.

  The head cleaning device according to a second aspect of the present invention is the head cleaning device according to the first aspect, wherein the cleaning unit swings the ejection head and a cleaning liquid supply unit that supplies the cleaning liquid to the surface of the ejection head. The solidified dirt adhered to the surface of the ejection head is washed by oscillating the ejection head in a state where the cleaning liquid supply means supplies the cleaning liquid to the surface of the ejection head. It is characterized by doing.

  According to the head cleaning device of the second aspect, the cleaning liquid is supplied to the surface of the ejection head by the cleaning liquid supply means and the ejection head is swung by the swinging means. Energy of vibration force by the moving means is given. Accordingly, the solidified dirt is peeled off from the surface of the ejection head and can be washed away cleanly.

  A head cleaning device according to a third aspect of the present invention is the head cleaning device according to the first aspect, wherein the cleaning means includes an ultrasonic wave generating means in a cleaning tank filled with the cleaning liquid, and the surface of the ejection head is disposed on the cleaning liquid. The solidified dirt adhered to the surface of the ejection head is washed by performing ultrasonic cleaning in a state of being immersed in the jet head.

  According to the head cleaning device of the third aspect, since ultrasonic cleaning is performed in a state where the surface of the jet head is immersed in the cleaning liquid of the cleaning tank, the solidified dirt is dissolved and high energy is applied by the ultrasonic vibration force. The solidified dirt can be peeled off from the jet head surface.

  According to a fourth aspect of the present invention, there is provided the head cleaning device according to the first aspect, wherein the cleaning means is in contact with the cleaning liquid tank for storing the cleaning liquid, the cleaning liquid tank, and the ejection head to be sealed. A side wall portion that forms a space; and a suction unit that is provided at each of the ejection ports of the ejection head and applies a suction force from the ejection port, and forms a sealed space by bringing the ejection head into contact with the side wall portion. In this state, the suction means sucks the cleaning liquid in the cleaning liquid tank, thereby cleaning the solidified dirt fixed to each of the ejection ports.

  According to the head cleaning device of the fourth aspect, when a suction force is applied by the suction means, a negative pressure suction force is applied to the sealed space, and the cleaning liquid in the cleaning liquid tank is sucked into each ejection port. As a result, it is possible to supply the cleaning liquid to the solidified dirt fixed to the ejection port, and to cause the energy to be peeled off by the suction force to act on the solidified dirt.

  According to a fifth aspect of the present invention, there is provided the head cleaning device according to the first aspect, wherein the cleaning means includes a suction tank including a suction means for generating a suction force, and the suction tank and the ejection head. A side wall portion that is in contact with each other to form a sealed space, and the suction means is filled in each ejection port of the ejection head in a state in which the ejection head is brought into contact with the side wall portion to form a sealed space. The solidified dirt adhering to each of the injection ports is washed by sucking the suspension that is being washed.

  According to the head cleaning device of the fifth aspect, the negative pressure suction force acts on the sealed space by the suction means provided in the suction tank, and the suction force acts on the suspension filled in each ejection port. Thus, the suspension can be supplied as a cleaning liquid to the solidified dirt fixed to the ejection port, and the energy to be peeled off by the suction force can be applied to the solidified dirt.

  A flat panel display manufacturing apparatus according to a sixth aspect of the present invention includes the head cleaning apparatus according to any one of the first to fifth aspects. A flat panel display according to a seventh aspect of the present invention is manufactured by the flat panel display manufacturing apparatus according to the sixth aspect. Examples of the flat panel display to which the head cleaning device of claims 1 to 5 can be applied include a liquid crystal display, an organic EL display, and a plasma display.

  An apparatus for manufacturing a solar cell according to an eighth aspect of the present invention includes the head cleaning device according to any one of the first to fifth aspects. A solar cell according to claim 9 of the present invention is manufactured by the solar cell manufacturing apparatus according to claim 8. The head cleaning device according to claims 1 to 5 can also be applied to a solar cell manufacturing device. Solar cell manufacturing equipment and flat panel display manufacturing equipment differ depending on whether the particles mixed in the suspension are metal particles or spacer beads, but the nature of the solvent (viscosity, surface tension, etc.) ) Is almost the same, and if a suspension in which metal particles are mixed is used, it can be used as a solar cell manufacturing apparatus for forming a metal film on a glass substrate, drawing metal wiring, and the like.

  According to a head cleaning method of a tenth aspect of the present invention, after performing a suspension spraying process of spraying a suspension downward from each ejection port arranged in the ejection head one or more times, A cleaning process is performed, and the cleaning process is performed after a liquid film removing process of sucking a liquid film of the suspension adhering to the ejection head in a non-contact manner a predetermined number of times, and then the suspension is dried. A cleaning step is performed in which a cleaning liquid is supplied to the solidified soil including particles in the suspension fixed to the ejection head to perform cleaning.

  According to the head cleaning method of the tenth aspect, the liquid film removing step having a short cleaning time is performed a plurality of times, and then the cleaning step with a high cleaning effect is performed. One effect can be achieved in a balanced manner. The cycle is such that the cleaning step is performed after the liquid film removing step is performed a plurality of times, but the number of times of the liquid film removing step in one cycle is set to an appropriate value depending on the degree of growth of solidified dirt adhered to the ejection head. be able to. It is also possible to perform cleaning by the liquid film removal step when the degree of growth of the solidified soil is within the allowable range of the landing accuracy of the suspension, and to perform the cleaning step when it exceeds the allowable range.

  In a head cleaning method according to an eleventh aspect of the present invention, after the suspension spraying step of spraying the suspension downward from each of the ejection ports arranged in the ejection head is performed one or more times, A cleaning process for performing cleaning was performed, and the cleaning process was performed by supplying a cleaning liquid to the solidified dirt including particles in the suspension dried and fixed to the ejection head for cleaning. Thereafter, a cleaning liquid removing step of sucking the cleaning liquid adhering to the ejection head in a non-contact manner is performed.

  According to the head cleaning method of the eleventh aspect, after the cleaning process performed by supplying the cleaning liquid, the cleaning liquid is sucked and removed in the liquid film removing process, so that the ejection head is cleaned. It becomes possible to remove the adhering cleaning liquid.

  The present invention provides two cleanings: removal of the suspension adhering to the ejection head in the form of a liquid film and cleaning of solidified soil containing particles in the suspension in which the suspension is dried and fixed It can correspond to. Further, by combining the removal of the liquid film and the cleaning of the solidified dirt, the two effects of improving the processing efficiency and high cleaning effect can be obtained in a balanced manner.

  Hereinafter, embodiments of the present invention will be described. In the following, a head cleaning apparatus will be described by exemplifying a liquid crystal display manufacturing apparatus which is one of flat panel displays. Accordingly, the ejection head is described as an ink jet head, the suspension as ink, and the particles in the suspension as spacer beads. However, the present invention is not limited to this. For example, when applied to a solar cell manufacturing apparatus, particles mixed in a suspension are nano-unit metal particles.

  In FIG. 1, a substrate 1 is a transparent thin plate such as glass. As the substrate 1, a TFT substrate on which a TFT circuit is formed or a color filter substrate on which a color filter is formed can be applied. Here, the substrate 1 will be described as a color filter substrate. The substrate 1 mainly has a pixel region 2 and a black matrix region 3. The pixel area 2 is a pixel area constituting pixels of each color of RGB, and the pixel area 2 is partitioned and formed by a black matrix area 3. In the black matrix region 3, spacers 4 are uniformly distributed in a lattice shape, and when the color filter substrate and the TFT substrate are joined by the spacers 4, a cell gap is formed as a predetermined gap. A liquid crystal panel is formed by sealing liquid crystal in a gap between the two substrates formed by the spacer 4. The spacer 4 may be formed not only on the color filter substrate side but also on the TFT substrate side.

  FIG. 2 shows an overall system configuration for performing ink spraying and ink jet head cleaning. As shown in the figure, the ink distribution stage 11 and the cleaning stage 12 are mainly divided. The ink spraying stage 11 that sprays ink on the substrate 1 mainly includes a transport table 20, ball screw means 21, an X-axis guide 22, a Y-axis guide 23, and an inkjet head 24. The ink jet head 24 has a head portion 25, a head moving mechanism 26, a head up / down mechanism 27, a head rotating mechanism 28, and a swing mechanism 29, and is schematically configured. Although FIG. 2 shows an example in which one inkjet head is provided, a plurality of inkjet heads may be provided.

  The substrate 1 is placed on the transfer table 20 and fixedly held by a vacuum suction means or the like. And the conveyance table 20 is conveyed by the ball screw means 21 along the X-axis guide 22 in the X direction in the figure. The ball screw means 21 is provided with a motor 21M with an encoder that operates at a predetermined clock. The motor 21M is rotationally driven by the motor 21M to convey the conveyance table 20 in the X direction at a predetermined pitch.

  The head moving mechanism 26 of the ink jet head 24 is mounted on a gate-shaped Y-axis guide 23 so as to straddle the transport table 20, and the entire ink-jet head 24 can move in the Y direction along the Y-axis guide 23. ing. The head up / down mechanism 27 is a mechanism for moving the head unit 25 up and down, and the head rotation mechanism 28 is a mechanism for rotating the head unit 25 at an arbitrary angle. The swing mechanism 29 is a mechanism that swings the head unit 25 in the X direction in the drawing.

  As shown in FIG. 3, the head unit 25 is composed of a plurality of minute nozzles 30 as ejection ports arranged at a predetermined pitch interval, and a certain amount of ink containing spacer beads is directed downward from each nozzle 30. Inject intermittently toward. As shown in FIG. 4, a tank 31 filled with ink is provided, and one end of a pipe 33 is immersed in the ink filled in the tank 31, and the other end is inserted into a nozzle hole 32 of each nozzle 30. Connected. One end of the pipe 34 faces the upper surface of the cleaning liquid in the tank 31, and the other end of the pipe 34 is connected to the pump 35. The uppermost surface of the tank 31 is sealed with a lid. Further, a vacuum pump 36 is provided in the pipe 33 in the middle, and a suction force can be applied to the nozzle hole 32 connected to the pipe 33 by the suction action of the vacuum pump 36. Each nozzle 30 is provided with a chamber piece 37, and an actuator 38 made of a piezoelectric element is attached to the chamber piece 37.

  When a voltage is applied to the actuator 38, the actuator 38 is deformed and the chamber piece 37 is expanded as shown by a two-dot chain line in FIG. As a result, ink is sucked into the chamber piece 37 from the tank 31 via the pipe 33. At this time, a constant suction force is always applied from the pump 35, and a negative pressure is applied to the upper liquid surface of the tank 31. Since the nozzle 30 is arranged downward, a force to flow down from the nozzle 30 due to gravity acts on the ink in the nozzle hole 32, but a constant action is applied to the ink in the nozzle hole 32 due to the suction action of the pump 35. The suction force acts and the state in which the nozzle hole 32 is filled is maintained. At this time, the tip of the ink maintains a state in which the concave meniscus MS is formed in the nozzle hole 32. Next, when the application of voltage to the actuator 38 is stopped, the original state is restored, the volume of the chamber piece 37 is reduced, and the corresponding ink is ejected from the nozzle 30 through the nozzle hole 32. .

  The cleaning stage 12 will be described with reference to FIGS. The cleaning stage 12 has a stage main body 41, a cleaning mechanism 42 as a cleaning means for cleaning solidified dirt (hereinafter simply referred to as solidified dirt) including spacer beads fixed to the inkjet head 24, and an inkjet head. And a suction mechanism 43 that suctions and removes ink adhering to the liquid film 24 in a non-contact manner. The cleaning mechanism 42 mainly includes a substantially rectangular cleaning block 51, and a liquid tank 52 having a predetermined depth is formed in the cleaning block 51. An O-ring 53 having a predetermined height as a side wall is provided on the upper surface of the cleaning block 51, and the O-ring 53 is disposed so as to surround the liquid tank 52. Suction holes 54 are provided at a plurality of locations on the bottom surface of the liquid tank 52, and liquid supply holes 55 are provided on the side surface of the liquid tank 52. A liquid supply pipe 56 is connected to the liquid supply hole 55, and the liquid supply pipe 56 is connected to an appropriate liquid supply mechanism. The number of liquid supply holes 55 may be one or plural. Further, the liquid supply hole 55 and the suction hole 54 can be provided at an arbitrary place.

  As shown in FIGS. 5 and 6, the suction mechanism 43 mainly includes a suction block 44, and a slit 45 is formed in the suction block 44. A pipe (not shown) is connected to the suction block 44, and the pipe and the slit 45 are connected inside the suction block 44. In order to apply the suction force from the slit 45, for example, a pump can be connected to the pipe, and the suction force can be applied from the slit 45 by the action of the pump.

  A support member 46 is connected to the suction block 44, and the support member 46 is attached to a slider 47. A guide rail 48 is provided on the outer wall of the stage main body 41, and the slider 47 is configured to be movable along the guide rail 48. A feed screw means 49 is provided for moving the slider 47. Since the guide rail 48 is provided in parallel with the X direction in FIG. 2, the suction block 44 moves in the X direction in FIG. 2 when the slider 47 moves along the guide rail 48 by the feed screw means 49. In the drawing, the guide rail 48 is provided on the outer wall of the stage main body 41. However, the guide rail 48 may be provided at any position, and may be provided independently, for example.

  Returning to FIG. 2, the inkjet control device C <b> 1 for controlling the head unit 25 is provided. The ink jet control device C1 is a device for performing operation control such as movement control of the head unit 25 and ink ejection by the nozzles 30. The ink jet control device C1 is connected to the computer C2, and by using the computer C2, the movement control and operation control of the head unit 25 can be set.

  Next, control of the inkjet head 24 will be described. The ink jet head 24 is usually positioned on the ink spraying stage 11 for spraying ink on the substrate 1. When ink is repeatedly sprayed from each nozzle 30 of the inkjet head 24, an ink liquid film adheres to the inkjet head 24, and when this liquid film is dried, the spacer beads are fixed and solidified stains are formed. Therefore, in order to improve the ink ejection state, cleaning is performed periodically. For this reason, when cleaning is performed, the ink spraying process is temporarily interrupted, and the head unit 25 is moved from the ink spraying stage 11 to the cleaning stage 12 for cleaning. This transfer control is performed by the inkjet control device C1.

  The timing for moving the ink jet head 24 to the cleaning stage 12 includes a process of spraying ink to all locations of the plurality of substrates 1 when the processing of spraying ink to all locations of the substrate 1 is completed. When it is finished, it can be performed at any timing, such as when ink is sprayed on a part of one substrate 1, but from the viewpoint of the necessity of cleaning the inkjet head 24 and processing efficiency, It is preferable to move to the cleaning stage 12 when the ink spraying process is completed for the substrate 1.

  When the transfer control signal is output from the ink jet control device C1, the head moving mechanism 26 moves along the Y-axis guide 23, whereby the ink jet head 24 moves from the ink spraying stage 11 to the cleaning stage 12. Then, cleaning is performed in the cleaning stage 12, and after the cleaning is completed, the ink jet head 24 is returned to the ink spraying stage 11 again, and ink spraying processing is performed. That is, the inkjet head 24 reciprocates between the ink spraying stage 11 and the cleaning stage 12.

  The cleaning stage 12 is provided with a cleaning mechanism 42 and a suction mechanism 43. Depending on the state of the inkjet head 24, it is possible to freely select whether the cleaning by the cleaning mechanism 42 or the cleaning by the suction mechanism 43 is performed. .

  First, cleaning of the inkjet head 24 by the suction mechanism 43 will be described. This cleaning is liquid film removal in which the liquid film attached to the inkjet head 24 is removed by suction without contact. Since the ink ejected from the nozzle 30 is a highly viscous liquid, part of the ink adheres to the surface of the inkjet head 24 (the surface of the head portion 25) and the nozzle hole 32 when the ink is ejected. The adhered ink is in a liquid state immediately after jetting, but gradually dries and becomes solidified stains. Since ink is a highly viscous liquid, solidified dirt adheres to the surface of the head portion 25 and the nozzle holes 32 with a strong adhesion. When the ink is newly ejected in a state where the solidified dirt is fixed to the inkjet head 24, the new ink adheres to the solidified dirt.

  Accordingly, when ink is repeatedly ejected from the nozzle 30, solidified dirt grows as a lump, and depending on the degree of growth, part or all of the nozzle 30 may be blocked and ink ejection cannot be performed normally. become. For example, when the solidified dirt lump grows so as to block a part of the nozzle 30, the ink ejection direction is greatly changed. Further, when solidified dirt lump grows to the extent that the entire nozzle 30 is blocked, ink is not ejected.

  Therefore, in the suction mechanism 43, a suction force is applied from the slit 45 provided in the suction block 44 to remove the liquid film that sucks the liquid film adhering to the inkjet head 24 in a non-contact manner. For this reason, the inkjet head 24 is moved to the upper part of the position SP where the liquid film is removed by a command from the inkjet control apparatus C1. As shown in FIG. 7, the position SP is the same position as the suction block 44 in the Y direction, slightly shifted in the X direction, and higher than the suction block 44 in the height direction. At this position SP, the head rotating mechanism 28 rotates the head portion 25 by 90 degrees, the head portion 25 is turned in the direction parallel to the X direction, and the head vertical mechanism 27 lowers the head portion 25. At this time, the head portion 25 and the suction block 44 are lowered to a position where a minute gap is formed in the height direction.

  In this state, the suction block 44 is moved in the X direction by moving the slider 47 along the guide rail 48. By moving the suction block 44 in a state where the surface of the inkjet head 24 and the suction block 44 face each other, the ink that is a liquid film attached to the surface of the inkjet head 24 is slid while being sucked. In particular, the portion of the surface of the head portion 25 where the liquid film of ink adheres is concentrated in the vicinity of the nozzle 30. Therefore, if the suction block 44 is moved along the X direction, which is the arrangement direction of the nozzles 30, it is efficient. In addition, the ink liquid film can be removed. Since the suction block 44 sucks while moving below the nozzle holes 32 of the nozzles 30, the ink adhering to the nozzle holes 32 is also absorbed by the suction block 44.

  At this time, as shown in FIG. 8, the suction block 44 slides in a non-contact state with the surface of the inkjet head 24, so that the surface of the inkjet head 24 is not damaged. However, as long as the liquid film 5F can be removed, the liquid film 5F may be removed by contact, but is preferably removed without contact. Here, cleaning is performed by moving the suction block 44 with the head portion 25 of the inkjet head 24 fixed, but the head portion 25 may be moved with the suction block 44 fixed. Good. That is, it is sufficient if the head unit 25 and the suction block 44 move relative to each other.

  The above is liquid film removal. The liquid film is removed only by moving the suction block 44 relative to the inkjet head 24 in a state in which a suction force is applied, so that the cleaning process can be completed in a short time with high processing efficiency. is there. However, since the ink is a highly viscous liquid, the ink liquid film may not be completely removed only by non-contact suction, and when the ink jet head 24 is transferred to the cleaning stage 12, the ink is already in some extent. In some cases, solidified dirt is formed by drying. Then, even if the liquid film is removed, a part of the solidified stain remains and may be fixed, and the solidified stain may grow by repeating the ejection of ink later.

  Therefore, as cleaning of the ink jet head 24, not only the removal of the liquid film but also the cleaning in which the cleaning liquid is supplied to the solidified dirt and peeled off is used in combination. Hereinafter, this cleaning will be described.

  When cleaning the inkjet head 24, the inkjet head 24 is moved from the ink spraying stage 11 so as to be positioned above the liquid tank 52 of the cleaning mechanism 42. At this position, the head rotating mechanism 28 rotates the head section 25 by 90 degrees, and the head lifting mechanism 27 lowers the head section 25. When the head portion 25 is lowered, the head portion 25 is lowered so that a minute gap is formed between the O-ring 53 and the head portion 25. As a result, the state shown in FIG. 9 is obtained.

  Then, the liquid is supplied to the liquid tank 52 from the liquid supply mechanism described above via the liquid supply pipe 56 and the liquid supply hole 55. This liquid is a cleaning liquid for cleaning the nozzle 30. As the cleaning liquid, IPA, ethylene glycol, or the like can be used. Here, the same kind of ink as the ink liquid ejected from the nozzle 30 is used as the ink cleaning liquid. However, although spacer beads are dispersed in the ink ejected from the nozzle 30, the ink cleaning liquid as the cleaning liquid does not include the spacer beads. When a large amount of ink cleaning liquid is supplied from the liquid supply mechanism at a high pressure, as shown in FIG. 10, the ink cleaning liquid overflows from the liquid tank 52, and the ink cleaning liquid is supplied to the surface of the head portion 25 located above.

  Then, the swing mechanism 29 is operated to swing the head unit 25 in the X direction. The swing mechanism 29 has a mechanism for swinging the head portion 25 by reciprocating it at a predetermined interval in the X direction, whereby the head portion 25 can be swung. By supplying the ink cleaning liquid to the solidified dirt fixed to the surface of the head portion 25, the dissolving force acts on the solidified dirt, and the fixing force is weakened. In this state, when the head portion 25 is swung to apply a vibration force, the solidified dirt is surely peeled off from the surface of the head portion 25. As a result, cleaning is performed to wash off the solidified dirt on the inkjet head 24.

  A minute gap is formed between the surface of the head portion 25 and the upper surface of the O-ring 53. This is because the head portion 25 and the O-ring are oscillated when the head portion 25 is swung to apply a vibration force. This is to prevent 53 from coming into contact. On the other hand, it is desirable that the head unit 25 be as close as possible to the liquid tank 52 in terms of supplying the ink cleaning liquid to the surface of the head unit 25. Therefore, a gap is provided between the surface of the head portion 25 and the upper surface of the O-ring 53, but this gap is made as small as possible.

  By the way, when the surface of the head portion 25 is being cleaned, the ink cleaning liquid overflows from the cleaning block 51. In order to collect the overflowed ink cleaning liquid, a receiving portion for the ink cleaning liquid may be disposed below the cleaning block 51, and the ink cleaning liquid recovered by the receiving portion may be reused. In order to reuse the collected ink cleaning liquid, for example, a filter, a pump, or the like is arranged.

  When the ink jet head 24 is cleaned, the ink cleaning liquid is supplied to the surface, so that the ink adheres as a liquid film to the surface of the ink jet head 24 after the cleaning. Since the spacer beads are not mixed in the ink cleaning liquid, even if the ink cleaning liquid adhering to the ink jet head 24 is dried, the spacer beads do not adhere to form solidified stains, but the ink cleaning liquid is also clean from the surface. It is desirable to remove it. Therefore, the head unit 25 is moved to the upper position of the suction block 44 to remove the liquid film and remove the ink cleaning liquid from the inkjet head 24. As a result, the ink cleaning liquid is supplied to the solidified dirt fixed to the inkjet head 24, the solidified dirt is washed off from the surface, and then cleaning is performed by removing the liquid film, thereby making the state of the inkjet head 24 extremely good. be able to.

  By the way, the cleaning performed by supplying the cleaning liquid is to remove the solidified dirt fixed to the ink jet head 24 by applying a dissolving force to the solidified dirt, so that a high cleaning effect is exhibited. A certain amount of time is required to swing 25. In other words, the cleaning exhibits a higher cleaning power than the liquid film removal, but the processing time becomes longer, and the liquid film removal cannot obtain the cleaning power as much as the cleaning, but the processing time is short. For this reason, washing and liquid film removal are applied in a balanced manner.

  Here, the removal of the liquid film does not provide as much cleaning power as cleaning with a cleaning liquid, but if the attached liquid film is suctioned without contact, it cannot be completely removed, but the ink is almost clean. Can be removed by suction. Therefore, the ink jet head 24 can be maintained in a good state only by removing the liquid film, and it is not necessary to perform cleaning so frequently. Conversely, frequent cleaning is not preferable from the viewpoint of processing efficiency. Therefore, the liquid film is removed a plurality of times, and cleaning is performed when it becomes necessary to perform cleaning using the cleaning liquid. By appropriately setting the number of times of removing the liquid film, the processing efficiency can be improved while obtaining a reliable cleaning effect. However, when there is a special circumstance such as when the viscosity of the ink is high, the cleaning must be performed at a high frequency, and thus cleaning and liquid film removal may be performed alternately.

  Next, another example of cleaning by cleaning will be described. In the first example, the surface of the head unit 25 is cleaned using the ultrasonic vibration tank 58 as shown in FIG. 11 instead of the liquid tank 52 as the cleaning mechanism 42. The ultrasonic vibration tank 58 is a tank constituted by an ultrasonic vibration plate, and the inside of the tank is filled with an ink cleaning liquid as a cleaning liquid. When shifting from the ink spraying stage 11, the inkjet head 24 is shifted to the upper position of the ultrasonic vibration tank 58, the head portion 25 is rotated and lowered, and the surface of the head portion 25 is immersed in the ink cleaning liquid. In this state, when the ultrasonic vibration plate is vibrated, a cavity is generated in the ink cleaning liquid inside the tank by intense vibration locally, and it is strong against the solidified dirt adhered to the nozzle 30 by the action of the cavity. Acts with a good dissolving power and is peeled off. By using the ultrasonic vibration tank 58, a high effect as cleaning by cleaning is exhibited.

  Next, a second example of cleaning by cleaning will be described with reference to FIG. The example described above is mainly for cleaning the spacer beads fixed to the surface of the inkjet head 24 (the surface of the head portion 25), but the second example is mainly for the nozzle hole 32 of the nozzle 30. The target is to wash the fixed spacer beads. As shown in FIG. 12, when the ink jet head 24 is moved from the ink spraying stage 11, the head portion 25 is moved so as to be positioned above the O-ring 53 arranged in the cleaning block 51. Then, the head portion 25 is brought into pressure contact with the O-ring 53 by being lowered as it is. As a result, a sealed space is formed in the liquid tank 52 by the cleaning block 51, the O-ring 53, and the surface of the head portion 25.

  As shown in FIG. 4, a pipe 33 is connected to each nozzle 30 of the inkjet head 24, and a vacuum pump 36 is provided in the pipe 33. By operating the vacuum pump 36, a suction force is applied from the pipe 33 to the nozzle hole 32 of the nozzle 30. The liquid tank 52 is a sealed space. When a suction force is applied from the nozzle hole 32, a negative pressure suction force is applied to the sealed space, and the ink filled in the liquid tank 52 with a strong force on the nozzle hole 32. The cleaning solution is aspirated. Thereby, the ink cleaning liquid is supplied to the solidified dirt fixed to the nozzle hole 32 and decomposed, and since the ink cleaning liquid is sucked with a strong force, an impact force is applied to wash off the solidified dirt.

  Next, a third example of cleaning by cleaning will be described. This example is also an example in which the solidified dirt fixed to the nozzle hole 32 of each nozzle 30 provided in the inkjet head 24 is washed. As shown in FIG. 13, the plurality of suction holes 54 provided on the bottom surface of the liquid tank 52 are collected at one place at the bottom of the liquid tank 52 and connected to a pipe 61 led out to the outside. The pipe 61 is provided with a pump 62 and a filter 63, one end of which is connected to a tank 64 for collecting the cleaning liquid. One end of the liquid supply pipe 56 is immersed in the cleaning liquid stored in the tank 64, and a pump 65 is provided in the liquid supply pipe 56.

  The pump 62 is operated in a state where the head portion 25 is pressed against the O-ring 53 of the cleaning block 51 and a sealed space is formed. By operating the pump 62, a suction force acts on the pipe 61, and a negative pressure suction force acts on the liquid tank 52 from the suction hole 54 provided on the bottom surface of the liquid tank 52. As described above, the nozzle hole 32 of each nozzle 30 is filled with ink, and the filled ink is sucked out of the nozzle hole 32 by the action of the negative pressure suction force. Accordingly, the cleaning liquid can be supplied to the solidified dirt fixed to the nozzle hole 32 and washed away.

  At this time, the ink sucked out from the nozzle holes 32 is collected into the tank 64 from the pipe 61 together with the cleaning liquid in the liquid tank 52. Since the pipe 61 is provided with the filter 63, the recovered cleaning liquid can be made a reusable cleaning liquid from which impurities are removed. Then, the cleaning liquid collected in the tank 64 can be pumped from the liquid supply pipe 56 by the pump 65 and returned to the liquid tank 52 to function as the liquid supply mechanism described above. Thereby, the collected cleaning liquid is reused.

  Next, a fourth example of cleaning by cleaning will be described. The cleaning in this example is also the cleaning of the solidified dirt adhering to the nozzle hole 32. As described above, the pipe 33 is connected to each nozzle 30 of the inkjet head 24, and the vacuum pump 36 is provided in the pipe 33. In the second example described above, a suction force is applied from the vacuum pump 36, but the vacuum pump 36 of the fourth example functions to discharge the ink filled in the nozzle holes 32. When the vacuum pump 36 is operated, the ink filled in the nozzle hole 32 is discharged. At this time, the ink is supplied to the solidified dirt fixed to the nozzle hole 32 and can be washed.

  Next, the protection function of the inkjet head 24 will be described. The reason why the spacer beads are fixed to the ink jet head 24 is that the liquid film of the attached ink is dried. If the liquid film of the ink is not dried, at least cleaning is unnecessary. Therefore, the surface of the inkjet head 24 is wetted to avoid drying the liquid film. For this reason, when the ink jet head 24 is not performing the ink spraying process or cleaning, the head portion 25 is brought into pressure contact with the O-ring 53 of the cleaning block 51 as shown in FIG. If the liquid tank 52 is filled with ink cleaning liquid and the head portion 25 is pressed against the O-ring 53 to form a sealed space, the sealed space becomes wet with the ink cleaning liquid. For this reason, it can be avoided that the ink liquid film adhering to the ink jet head 24 is dried, the state of the liquid film is maintained, and solidified dirt can be prevented from being formed.

  By ejecting the ink, a liquid film of ink adheres to the inkjet head 24, but by protecting the inkjet head 24, it is possible to avoid the formation of solidified dirt. For this reason, although it is necessary to remove the ink liquid film, it is possible to avoid the formation of solidified stains, so that it is not necessary to perform cleaning using a cleaning liquid that requires a relatively long time. Therefore, the overall processing efficiency is improved.

  In addition, as described with reference to FIG. 4, the meniscus MS made of ink is formed in the nozzle hole 32. If the nozzle hole 32 of the ink jet head 24 is exposed to the air, the ink meniscus MS is dried and destroyed, and even if the actuator 38 is deformed, it is impossible to eject ink appropriately. Therefore, as shown in FIG. 14, the ink meniscus MS can be protected by placing the inkjet head 24 in a wet environment.

It is structure explanatory drawing of the board | substrate with which a spacer is spread | dispersed. It is an external view which shows the whole structure of an ink dispersion | distribution stage. It is a structure explanatory view showing the tip part of an ink jet head. It is explanatory drawing of the operation | movement which ejects the ink from the nozzle which comprises an inkjet head. It is an external view of a cleaning stage. It is a top view of a cleaning stage. It is the figure which showed the positional relationship of the inkjet head when performing a liquid film removal. It is a figure explaining operation | movement when a suction mechanism attracts | sucks the liquid film adhering to the nozzle. It is the figure which showed the positional relationship of the inkjet head when performing cleaning by washing | cleaning. It is sectional drawing which shows an inkjet head and a liquid tank. It is sectional drawing explaining the cleaning by the washing | cleaning in a 1st example. It is sectional drawing explaining the cleaning by washing | cleaning in a 2nd example. It is sectional drawing explaining the cleaning by washing | cleaning in a 3rd example. It is a figure explaining the protection function of an inkjet head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Pixel area 3 Black matrix area 4 Spacer 5F Liquid film 11 Ink dispersion stage 12 Cleaning stage 24 Inkjet head 25 Head part 30 Nozzle 42 Cleaning mechanism 43 Suction mechanism 44 Suction block 45 Slit 47 Slider 52 Liquid tank 53 O-ring 54 Suction Hole 55 Liquid supply hole 58 Ultrasonic vibrating tank MS meniscus

Claims (11)

A liquid film removing means for sucking and removing the liquid film of the suspension adhering to the ejection head provided by arranging a plurality of ejection ports for ejecting the suspension downward in a row in a non-contact manner;
Cleaning means for supplying a cleaning liquid to the solidified soil containing particles in the suspension dried and fixed to the ejection head, and cleaning the solidified soil;
A head cleaning device. The cleaning means includes
Cleaning liquid supply means for supplying the cleaning liquid to the surface of the ejection head; and swing means for swinging the ejection head;
In the state where the cleaning liquid supply means supplies the cleaning liquid to the surface of the ejection head, the solidified dirt adhered to the surface of the ejection head is washed by swinging the ejection head.
The head cleaning device according to claim 1. The cleaning means includes
Provided with ultrasonic generation means in the cleaning tank filled with the cleaning liquid,
Cleaning the solidified dirt adhered to the surface of the ejection head by performing ultrasonic cleaning in a state where the surface of the ejection head is immersed in the cleaning liquid;
The head cleaning device according to claim 1. The cleaning means includes
A cleaning liquid tank that stores the cleaning liquid, a side wall that is in contact with the cleaning liquid tank and the ejection head to form a sealed space, and each ejection port of the ejection head, and a suction force is applied from the ejection port. A suction means,
In the state where the ejection head is brought into contact with the side wall portion to form a sealed space, the suction means sucks the cleaning liquid in the cleaning liquid tank, thereby cleaning the solidified dirt fixed to each of the ejection ports. To do,
The head cleaning device according to claim 1. The cleaning means includes
A suction tank provided with suction means for generating a suction force, and a side wall portion that is in contact with the suction tank and the ejection head to form a sealed space,
In a state where the ejection head is brought into contact with the side wall portion to form a sealed space, the suction means sucks the suspension filled in each ejection port of the ejection head, thereby causing each ejection port to Washing the solidified dirt that has adhered,
The head cleaning device according to claim 1.   An apparatus for manufacturing a flat panel display, comprising the head cleaning device according to any one of claims 1 to 5.   A flat panel display manufactured by the flat panel display manufacturing apparatus according to claim 6.   An apparatus for manufacturing a solar cell, comprising the head cleaning device according to any one of claims 1 to 5.   The solar cell manufactured with the manufacturing apparatus of the solar cell of Claim 8. After performing a suspension spraying process of spraying the suspension downward from each ejection port arranged in the ejection head one or more times, a cleaning process for cleaning the ejection head is performed,
The cleaning step is a suspension in which the suspension is dried and fixed to the ejection head after performing a liquid film removal step of sucking a liquid film of the suspension adhering to the ejection head in a non-contact manner a predetermined number of times. Performing a cleaning process by supplying a cleaning liquid to the solidified dirt containing particles in the liquid and cleaning it;
A head cleaning method. After performing a suspension spraying process of spraying the suspension downward from each ejection port arranged in the ejection head one or more times, a cleaning process for cleaning the ejection head is performed,
The cleaning step was performed by supplying a cleaning liquid to the solidified soil including particles in the suspension that was dried and fixed to the ejection head and washed, and then adhered to the ejection head. Performing a cleaning liquid removal step of sucking the cleaning liquid in a non-contact manner;
A head cleaning method.

Images