JP2006126496A - Head module and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which has high discharge stability of spacer particles. <P>SOLUTION: A head module 2 of the present invention has a primary head body 20 which is divided into a transport chamber 22 and a discharge chamber 21 by an internal filter 30. Liquid spacer dispersion is passed through a transport path 12, supplied to the transport chamber 22 from an intake 23 to flow in the transport chamber 22 from the intake 23 to an outlet 24, and returned to the transport path 22 from the outlet 24 to be sent to the intake 23 again. Thus, the liquid spacer dispersion flows in the transport chamber 22 isolated from the discharge chamber 21 by the internal filter 22, so even if the flow rate of the liquid spacer dispersion varies, no influence is exerted on the discharge chamber 21 on the side of a nozzle plate 26, so that the amount of liquid discharge from a jet hole of the nozzle plate 26 and the number in each droplet are high in stability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spacer ink head module, an ink supply module, and a spacer forming apparatus incorporating them.

  Conventionally, as a method of disposing a spacer at a predetermined position on the substrate to maintain a uniform cell gap between the color filter substrate of the liquid crystal display and the array substrate, an ink in which the spacer is dispersed is used with a printing device. A method for printing on a substrate has been proposed.

  In general, an ink jet printer that ejects ink from nozzles to a printing position is used as a printing apparatus. However, if the spacers are not evenly dispersed in the ink, ejection from the nozzles becomes unstable, resulting in ejection failure. In addition, there is a problem that the number of spacers in the ink droplets ejected from the nozzles is not stable, as well as an abnormality in the ejection speed and ejection direction.

  For example, in Japanese Patent Laid-Open No. 11-7028, a stirring tank that contains a solution containing a spacer has a cooling means and an ultrasonic generator using a piezoelectric element, and the temperature of the solution containing the spacer in the stirring tank is raised. Although a printer that stirs and disperses by ultrasonic waves without discharging and discharges the spacers is described, the sedimentation of the spacers occurring in the piping between the agitation tank and the head, the inside of the head ink chamber, and the like becomes a problem.

  Japanese Patent Application Laid-Open No. 2002-72218 describes a printing apparatus that can circulate ink in the ink chamber of the head. However, there is a problem that the head nozzle plate is clogged with foreign matter mixed in the ink.

Furthermore, in recent years, the length of the ink supply line from the ink bottle to the head module has become longer with the increase in the size of the printing apparatus, and the sedimentation and aggregation of the spacers inside the ink supply line cause various problems.
Japanese Patent Laid-Open No. 11-7028 JP 2002-72218 A JP 2002-277622 A JP 2003-275659 A

  The present invention was created to solve the above-described disadvantages of the prior art, and an object of the present invention is to provide a head module and a printing apparatus that have good dischargeability without causing precipitation of particles such as spacers in the ink. It is.

In order to solve the above-mentioned problems, the invention according to claim 1 is to transport an inner hollow head body, a nozzle plate constituting one wall surface of the head body, and a spacer dispersion supplied from a storage system to the head body. The nozzle plate is provided with an ejection hole, and the spacer dispersion transported into the head body is a head module configured to be discharged from the ejection hole, The internal space of the head body is divided into a discharge chamber on the nozzle plate side and a transport chamber on the opposite side of the nozzle plate by an internal filter that is disposed inside the head main body and allows the spacer dispersion liquid to pass through. On the wall surface of the transport chamber, there are an inlet for supplying the spacer dispersion liquid, and an outlet provided at a distance from the inlet for discharging the spacer dispersion liquid. Vignetting, the transport system is a head module having a pump for returning the liquid is discharged from the discharge port to the inlet.
The invention according to claim 2 is the head module according to claim 1, wherein the transport system has a discharge valve, and the spacer dispersion liquid is transferred from the discharge port to the inflow port by switching the discharge valve. The head module is configured to switch from a returning circulation state to a discharge state discharged from the discharge port to the storage system.
A third aspect of the present invention is the head module according to the first or second aspect, wherein spacer particles are dispersed in the spacer dispersion liquid, and the spacer is disposed inside the internal filter. The head module has a diameter that is at least twice the diameter of the particles, is provided with a passage through which the spacer dispersion liquid passes, and the diameter of the ejection hole is larger than the diameter of the passage.
According to a fourth aspect of the present invention, there is provided a storage system in which a spacer dispersion liquid is stored, one or more head modules that discharge the spacer dispersion liquid, the head modules connected to the storage system, and the spacer A supply system for supplying the dispersion liquid to each head module; and a discharge system for connecting each head module to the storage system and returning the spacer dispersion liquid discharged from the head to the storage system, Each head module has a supply valve that switches between permitting and stopping the supply of the spacer dispersion liquid, and when the supply valve is in an allowed state, the spacer dispersion liquid is supplied from the supply system to each head module. And a spacer for connecting the supply system and the discharge system when the supply valves are stopped. Wherein without passing through the head modules, the configuration printing device to return to the discharge system through the connection system.
The invention according to claim 5 is the printing apparatus according to claim 4 having the head module according to any one of claims 2 and 3, wherein the discharge valve is in the circulation state, and the supply valve is turned on. In a stopped state, the printing apparatus is configured so that the circulation of the spacer dispersion liquid from the discharge port to the inflow port and the circulation of returning to the discharge system without passing through the head module are performed simultaneously. is there.
The invention according to claim 6 is a storage system in which the spacer dispersion liquid is stored, one or more head modules that discharge the spacer dispersion liquid, and a supply system that connects the head modules to the storage system. A discharge system for connecting each head module to the storage system and returning the spacer dispersion discharged from the head module to the storage system, each head module including a hollow head body, Nozzle plate composed of one wall surface of the head body, a supply path for supplying the spacer dispersion liquid from the supply system to the head body, and a discharge path for returning the spacer solution discharged from the head body to the discharge system The spacer dispersion liquid supplied to the head body is configured to be discharged from an ejection hole provided in the nozzle plate. In the printing apparatus, an internal space of the head main body is divided into a discharge chamber on the nozzle plate side and a transport chamber on the opposite side of the nozzle plate by an internal filter disposed therein, and the transport chamber The wall surface is provided with an inlet for supplying the spacer dispersion liquid from the supply path, and a discharge port provided apart from the inlet and for returning the spacer dispersion liquid to the discharge path. And the discharge path are connected to the inlet and the outlet, respectively, and the spacer dispersion sent to the supply path passes through the transport chamber before being sent to the discharge path. .
The invention according to claim 7 is the printing apparatus according to claim 6, wherein the supply path of each head module is sequentially connected to the supply system along the direction in which the spacer solution flows, and on the upstream side. When the supply valve of the upstream supply path connected to the supply system is closed and the supply valve of the downstream supply path connected to the supply system is opened downstream of the upstream supply path, the spacer dispersion liquid is The printing apparatus does not pass through the transport chamber connected to the upstream supply path and passes through the transport chamber connected to the downstream supply path.

  It becomes possible to stably supply the ink in the liquid in which the spacer forming particles are dispersed to the head without agglomerating and settling, and it is possible to put to practical use a spacer discharge device for a large substrate using a plurality of heads. .

  2 indicates a head module of the present invention. The head module 2 includes a head body 20, a nozzle plate 26, a small discharge chamber 27 provided with a piezoelectric element, a transport system 10, and a supply valve. 41 and a discharge valve 42.

  The inside of the head main body 20 is hollow, and the nozzle plate 26 is constituted by a bottom wall which is one wall surface of the head main body 20. The small discharge chamber 27 is disposed on the surface of the nozzle plate 26 facing the inside of the head main body 20.

  Inside the head body 20, an internal filter 30 is disposed away from both the small discharge chamber 27 on the nozzle plate 26 and the wall surface on the ceiling side of the head body 20, and the internal space of the head body 20 is The space is divided into a space between the internal filter 30 and the ceiling side wall and a space between the internal filter 30 and the small discharge chamber 27.

  Reference numeral 21 in FIG. 2 denotes a discharge chamber that is surrounded by a nozzle plate 26, an internal filter 30, and a side wall of the head body 20, and in which a small discharge chamber 27 in which a spacer dispersion liquid described below is discharged is disposed. Reference numeral 22 in the figure denotes a ceiling side wall surface that is the wall surface of the head body 20 opposite to the nozzle plate 26, an internal filter 26, and a transport chamber 22 surrounded by the side wall of the head body 20.

  Here, the ceiling side wall surface of the head body 20 is elongated, and through holes are provided at both ends in the longitudinal direction, respectively, and an inlet 23 through which the spacer dispersion liquid flows into the transport chamber 22 through the through holes. In addition, an outflow port 24 through which the spacer dispersion liquid flows out from the transport chamber 22 is provided.

  Since the diameter of the inflow port 23 and the outflow port 24 is very short compared with the length of the ceiling side wall surface, the inflow port 23 and the outflow port 24 are in a state of being spaced apart from each other.

  The transport system 10 includes a transport path 12 having one end connected to the inlet 23 and the other end connected to the outlet 24, and a buffer chamber 17 provided in the middle of the transport path 12.

  One end of a supply pipe 56 is connected to the buffer chamber 17, and the supply valve 41 is provided in the middle of the supply pipe 56. When the supply valve 41 is closed and the buffer chamber 17 is shut off from a supply system described later, The spacer dispersion liquid is not supplied to the buffer chamber 17, but in a permissive state in which the supply valve 41 is closed and the buffer chamber 17 is connected to the supply system, the spacer dispersion liquid in the supply system is supplied into the buffer chamber 17. The spacer dispersion liquid is stored in the tank.

  The head module 2 has a liquid volume sensor (not shown) that detects the liquid volume in the buffer chamber 17. When the liquid volume in the buffer chamber 17 is less than the specified volume, the supply valve 41 is allowed, and conversely When the amount of liquid in the buffer chamber 17 is equal to or greater than the specified amount, the supply valve 41 is stopped. Accordingly, when the amount of liquid in the buffer chamber 17 decreases due to printing, the spacer dispersion liquid is replenished from the supply system 51, and the amount of liquid in the buffer chamber 17 is always maintained at a specified amount.

  The head module 2 has ultrasonic irradiation means (not shown), and the spacer dispersion liquid stored in the buffer chamber 17 is agitated by ultrasonic vibration generated by the ultrasonic irradiation means. The spacer particles do not settle and are maintained dispersed in the buffer chamber 17.

  A temperature control means (not shown) is attached to the buffer chamber 17, and when the temperature of the spacer dispersion liquid stored in the buffer chamber 17 rises, the buffer chamber 17 is cooled by the temperature control means, and the spacer is transferred by heat conduction. The dispersion is cooled. Therefore, even if the temperature of the spacer dispersion liquid in the buffer chamber 17 rises due to ultrasonic irradiation, the temperature of the spacer dispersion liquid is always kept constant by the temperature control means.

  A circulation pump 15 is attached to the transport path 12 at a position between the outlet 24 and the buffer chamber 17, and when the circulation pump 15 is operated, the spacer dispersion in the buffer chamber 17 is opposite to the circulation pump 15. When it is pushed to the side and flows in the transport path 12 toward the inflow port 23 and is supplied from the inflow port 23 into the transport chamber 22, it flows between the inflow port 23 and the outflow port 24.

  FIG. 3 is an enlarged sectional view of the head body 20. The internal filter 30 is configured by a filter having a passage through which a solution passes, such as a metal mesh filter or a non-woven fabric. A part of the spacer dispersion flowing from the inflow port 23 toward the outflow port 24 is transported to the discharge chamber 21 through the passage of the internal filter 30.

  The code | symbol 39 of FIG. 3 has shown the spacer particle | grains disperse | distributed to the spacer dispersion liquid. The passage of the internal filter 30 is set to be twice or more the diameter of the spacer particles 39, so that the spacer dispersion liquid is conveyed to the discharge chamber 21 in a state where the spacer particles 39 are dispersed.

  A piezo support plate 35 provided with a plurality of holes is disposed between the nozzle plate 26 and the internal filter 30 so as to be separated from the nozzle plate 26, and the small discharge chamber 27 includes the nozzle plate 26 and the piezo support plate. 35.

  The nozzle plate 26 is provided with one or more ejection holes 32. Here, there are a plurality of ejection holes 32, and one small ejection chamber 27 is provided on each ejection hole 32. The piezo elements 36 of the small discharge chambers 27 are provided in the vicinity of the respective ejection holes 32, and the piezo elements 36 located in the vicinity of the desired ejection holes 32 are vibrated, so that the spacers are separated from the desired ejection holes 32. The dispersion liquid can be discharged. The piezo element 35 may be provided as a partition that separates the small discharge chambers 27 adjacent to each other, or may be provided on the side wall of the small discharge chamber 27.

  When the spacer dispersion liquid is discharged and the spacer dispersion liquid in the discharge chamber 21 is consumed, the height of the surface (meniscus) where the spacer dispersion liquid in the ejection holes 32 contacts the atmosphere changes.

  The buffer chamber 17 is connected to the tank 80 of the meniscus control mechanism 8, and the liquid level of the spacer dispersion liquid and solvent stored in the tank 80 changes in conjunction with the height of the meniscus. The liquid level of the buffer liquid is detected by a liquid level sensor (not shown), and the spacer dispersion liquid or solvent is returned from the tank 80 to the buffer chamber so that the meniscus is returned to a predetermined height by a pressure reducing mechanism linked to the liquid level sensor. 17 is supplied.

  That is, in the head module 2, the supply of the spacer dispersion liquid from the supply system 51 to the head module 2 is controlled, and the liquid amount in the head module 2 is finely adjusted by the meniscus control mechanism 8, so that the head module 2 is always adjusted. The amount of the liquid inside is kept constant, and as a result, the discharge of the spacer dispersion liquid is performed stably.

  Of the spacer dispersion liquid passing through the transport chamber 22, the one not supplied to the discharge chamber 21 returns to the transport path 12 from the outlet 24.

  The discharge valve 42 is attached at a position between the outlet 24 of the transport path 12 and the buffer chamber 17. One end of a discharge pipe 57 is connected to the transport path 12 via a discharge valve 42. The other end of the discharge pipe 57 is connected to a discharge system, which will be described later. In a discharge state in which the discharge valve 42 is switched and the transport path 12 is connected to the discharge system, the spacer dispersion returned from the outlet 24 to the transport path 12 is Although it is discharged to the discharge system through the discharge pipe 57, the spacer dispersion liquid that has returned from the outlet 24 to the transport path 12 returns to the buffer chamber 17 in a circulating state in which the transport path 12 is blocked from the discharge system. ing.

  Since the spacer dispersion liquid returned to the buffer chamber 17 is sent again toward the inflow port 23, when the circulation pump 15 is operated in a circulating state, the spacer dispersion liquid flows between the buffer chamber 17 and the transport chamber 22. It comes to circulate.

  An external filter 19 is provided between the inlet 23 and the buffer chamber 17. The external filter 19 allows the spacer particles to pass through, but removes objects (including dust and aggregates of spacer particles) larger than the spacer particles. Therefore, only the dispersion liquid in which the spacer particles are dispersed reaches the inlet 23.

  Next, a printing apparatus of the present invention using this head module 2 will be described. Reference numeral 1 in FIG. 1 shows an example of the printing apparatus of the present invention.

  The printing apparatus 1 has one or more of the storage system 5, the circulation path 50, and the head module 2 described above. Here, four head modules 2 are provided, and each head module 2 and each member of the head module 2 are distinguished from each other by adding subscripts a to d.

  The storage system 5 has a storage tank 58 and a buffer tank 59. Inside the storage tank 58, a spacer dispersion liquid in which spacer particles as resin particles are dispersed in a solvent is stored, and the spacer dispersion liquid is supplied from the storage tank 58 to the buffer tank 59 by a supply pump 79, The liquid is temporarily stored in the buffer tank 59, and the excessive liquid stored in the buffer tank 59 is returned to the storage tank 58.

  The storage tank 58 and the buffer tank 59 are respectively provided with stirring means (not shown). The spacer dispersion liquid stored in the storage tank 58 and the buffer tank 59 is constantly stirred by the stirring means, and the spacer particles are mixed. The dispersed state is maintained without precipitation.

  The circulation path 50 is composed of a pipe having one end and the other end connected to a buffer tank 59. A general circulation pump 55 is provided in the middle of the circulation path 50, and when the large circulation pump 55 is operated, The spacer dispersion liquid in the tank 59 is drawn into the circulation path 50 from one end, flows in the circulation path 50 toward the other end, and then returns to the buffer tank 59 from the other end.

  If the side where the spacer dispersion liquid is drawn into the circulation path 50 is upstream and the side where it is discharged to the buffer tank 59 is downstream, the supply pipes 56a to 56d of the head modules 2a to 2b are connected to one end upstream of the circulation path 50. Are connected one by one from the upstream toward the downstream.

  Reference numeral 51 in FIG. 1 indicates a supply system that is a portion upstream of the position where the most downstream supply pipe 56d of the circulation path 50 is connected, and the spacer dispersion flowing in the supply system 51 is supplied from the supply pipes 56a to 56a. The buffer chamber 17 is supplied from 56d.

  The discharge pipes 57a to 57d of each of the head modules 2a to 2d are sequentially connected to the circulation path 50 one by one from the upstream to the downstream at a position downstream of the supply system 51. Reference numeral 52 in FIG. 1 indicates a discharge system which is a portion downstream of the position where the most upstream discharge pipe 57a of the circulation path 50 is connected. The spacer dispersion liquid discharged from each of the head modules 2a to 2d is It returns to the discharge system 52.

  The most upstream discharge pipe 57a is connected to the transport path 50 further downstream than the most downstream supply pipe 56d. Therefore, the spacer dispersion liquid that has passed through the supply system 51 without being supplied to the head modules 2a to 2d passes through a portion of the transport path 50 between the most downstream supply pipe 56d and the most upstream discharge pipe 57a. It passes through and is discharged to the discharge system 52. Reference numeral 53 in FIG. 1 is a portion of the transport path 50 between the most downstream supply pipe 56 d and the most upstream discharge pipe 57 a, and represents a connection system that connects the supply system 51 to the discharge system 52. Show.

  Next, an example of a process for printing the spacer dispersion using the printing apparatus 1 will be described. The general circulation pump 55 is operated with each supply valve 41 in an allowable state and each discharge valve 42 in a circulation state. Even if the flow rate of the spacer dispersion flowing through the supply system 51 is allowed in each of the supply pipes 56a to 56d, all the flow from the supply pipe 56d located at the uppermost stream to the supply pipe 56d located at the most downstream position. Since the flow rate is sufficient to supply the spacer dispersion liquid, the spacer dispersion liquid is stored in the buffer chambers 17 of the head modules 2a to 2d.

  When each supply valve 41 is in a stopped state, each discharge valve 42 is in a circulation state, and the circulation pump 15 is operated, as described above, the spacer dispersion liquid is separated from the buffer chamber 17 in each head module 2a to 2d. It circulates between the transport chambers 22.

  When the substrate that is the printing object is disposed at a position facing the nozzle plate 26 of each of the head modules 2a to 2d and the spacer dispersion liquid is discharged from the ejection holes 32 that are located immediately above the printing position to be printed on the substrate, A spacer dispersion is applied to the printing position of the substrate (printing).

  Since the spacer particles easily settle, if the spacer dispersion liquid does not move inside the head body, the spacer particles are separated, and the number of spacer particles discharged at one time from the ejection holes 32 varies. If the spacer dispersion liquid is circulated between the buffer chamber 17 and the transport chamber 22 at all times, the spacer dispersion liquid does not settle inside the head module 2.

  When the above-described circulation of the spacer dispersion liquid is maintained, the spacer dispersion liquid always flows inside the transport chamber 22, but since the amount pushed out by the circulation pump 15 is constant, when the spacer dispersion liquid is discharged from the ejection holes 32, When not, the flow rate of the spacer dispersion flowing in the transport chamber 22 changes.

  The discharge amount from the ejection hole 32 is controlled by the vibration of the liquid surface by the piezo element 36. However, when the flow velocity of the spacer dispersion liquid passing over the ejection hole 32 varies, the pressure applied to the ejection hole 32 also varies. The discharge amount from the hole 32 is not expected.

  In the present invention, the flow of the spacer dispersion liquid is generated in the transport chamber 22 separated from the discharge chamber 21 by the internal filter 30, so that the pressure received by the ejection holes 32 even if the flow velocity of the spacer dispersion liquid flowing through the transport chamber 22 slightly varies. Has no effect. Accordingly, an amount controlled by the piezo element 36 is always discharged from the ejection hole 32, and stable discharge can be performed.

  If the general circulation pump 55 is always operated at the time of printing, the spacer dispersion liquid is supplied to the supply system 51. Therefore, if the liquid amount in the buffer chamber 17 is reduced by the discharge from the ejection holes 32, the supply valve 41 is allowed. The spacer dispersion liquid is always supplied to the head modules 2a to 2d.

  Further, when the supply valve 41 is stopped, the spacer dispersion flowing in the supply system 51 is sent to the discharge system 52 through the connection system 53 without passing through the head modules 2 a to 2 d, and to the buffer tank 59. Return. Thus, even when the spacer dispersion liquid is not sent into the head modules 2a to 2d, the spacer dispersion liquid circulates between the circulation path 50 and the buffer tank 59 and does not stagnate inside the circulation path 50. The spacer particles do not settle in the middle of the circulation path 50.

  Since the spacer particles tend to settle, for example, when printing is stopped for a short time, always maintain the circulation between the circulation path 51 and the buffer tank 59 and the circulation in each of the head modules 2a to 2d. Is preferred.

  The cleaning means for cleaning the inside of the printing apparatus 1 for a long time will be described. The printing apparatus 1 includes a solvent tank 71 in which a cleaning liquid such as an organic solvent is disposed, and a cleaning for transporting the cleaning liquid. A path 72 is provided separately from the supply system 51.

  Referring to FIGS. 1 and 2, one end of the cleaning pipe 75 of each head module 2 a to 2 a is connected to the cleaning path 72. When the switching valve 76 of the cleaning pipe 75 is opened, the cleaning liquid is cleaned from the cleaning path 72. Supplyed to the tube 75.

  The cleaning pipe 75 branches into a discharge side pipe 73 connected to the discharge chamber 21 and a transport path side pipe 74 connected to the transport path 12. By switching the branch valve 77, the cleaning pipe 75 is disconnected from the transport path side pipe 74. When shut off and connected to the discharge side pipe 73, the cleaning liquid flows into the discharge side pipe 73. When the discharge side valve 78 provided in the middle of the discharge side pipe 73 is opened, the cleaning liquid is supplied to the discharge chamber 21 and the discharge liquid 21. The inside is cleaned with a cleaning solution. The cleaning liquid after cleaning is discharged to the outside through the ejection holes 32.

  The transportation path side pipe 74 is connected to the transportation path 12 between the buffer chamber 17 and the external filter 19. When the cleaning liquid is supplied to the transportation path side pipe 12 by switching the branch valve 77 and the cleaning liquid is caused to flow to the external filter 19 side of the transportation path 12 by switching the transportation path side valve 79 that connects the transportation path side pipe 74 to the transportation path 12, The external filter 19 and the transport chamber 22 are cleaned with the cleaning liquid. At this time, if the exhaust valve 42 is brought into an exhaust state, the washed spacer dispersion liquid is discharged to the discharge system 52 and discharged from the discharge system 52 to the drain 3.

  The above has described the case where the spacer dispersion liquid is simultaneously supplied into each of the head modules 2a to 2d to perform printing. However, the present invention is not limited to this, and one or two of the plurality of head modules are used. Printing may be performed with the remaining head modules after the printing is completed by selecting more than one and printing.

  The circulation pump 15 is not limited to extruding the spacer dispersion liquid, and may be circulated in the transport path 12 by sucking the spacer dispersion liquid, or may be further provided with two types of pumps for extruding the spacer dispersion liquid and the suction pump. In addition, as long as the installation location is also in the middle of the transportation path 12, the location may not be between the outlet 24 and the buffer chamber 17. In short, the circulation pump 15 only needs to circulate the spacer dispersion liquid between the transport system 10 and the transport chamber 12.

  The above has described the case where the spacer circulating liquid is circulated in the head module 2, but the present invention is not limited to this.

  Reference numeral 2 ′ in FIG. 4 indicates a head module used in another example printing apparatus 1 ′. The head module 2 'includes a buffer chamber 17, the external filter 19, and the head main body 20 having the same structure as the head module 2 shown in FIG. The filter 19 and the buffer chamber 17 are connected in series to the supply system 51 and the discharge system 52, respectively. When the supply valve 41 is allowed, the spacer dispersion supplied from the supply system 51 is supplied to the buffer chamber 17. Then, after passing through the external filter 19 and passing through the inflow port 23 into the transport chamber 22 and flowing through the inside of the transport chamber 22, the discharge system 52 does not return to the buffer chamber 17 without being returned to the pipe from the outflow port 24. To be discharged.

  4 indicates a supply path for supplying the spacer dispersion liquid from the supply system 51 to the inlet 23, and reference numeral 82 in FIG. 4 indicates a discharge path for returning the spacer dispersion liquid from the outlet 23 to the discharge system 52. ing.

  The spacer dispersion returned to the discharge system 52 returns to the buffer tank 59 and is supplied to the supply system 51 again by the operation of the general circulation pump 55. That is, in this printing apparatus 1 ′, the spacer dispersion liquid circulates between the storage system 5, the supply system 51, the supply path 81, the transport chamber 22, the discharge path 82, and the discharge system 52 stagnation. As a result, the spacer particles are difficult to settle.

  Therefore, if printing is performed while circulating the spacer dispersion liquid, the number of spacer particles in the droplets discharged from the ejection holes 32 does not vary.

  In this printing apparatus 1 ′, two or more head modules 2 ′ may be connected to the same supply system 51 and discharge system 52, in which case the head module 2 ′ located upstream of the supply system 51 If the supply valve 41 is allowed, the spacer dispersion liquid is preferentially supplied to the head module 2 '. Further, if the supply valve 41 of the head module 2 ′ located upstream is stopped, the spacer dispersion flowing in the supply system 51 has priority over the head module 2 ′ adjacent to the downstream of the head module 2 ′. Will flow into. Further, if the amount of the spacer dispersion liquid flowing to the supply system 51 is sufficiently increased, the spacer dispersion liquid can be simultaneously supplied to the plurality of head modules 2 ′, and one storage system 5 and one supply system can be supplied. The spacer dispersion liquid is circulated between 51, the plurality of head modules 2 ′, and one discharge system 52.

  In the present invention, the type of spacer particles used in the invention is not particularly limited, and for example, those having a diameter of 4 μm or more and 6 μm or less can be used.

  The type of the internal filter 30 is not particularly limited, and various materials such as a nonwoven fabric and a metal filter can be used as long as the material does not easily adsorb the spacer particles in the spacer dispersion liquid. The diameter is preferably at least twice the diameter of the spacer particles.

  The shape and size of the ejection holes 32 are not particularly limited, but those having a diameter that is at least twice the diameter of the passage of the internal filter 30 are preferable in consideration of stable discharge performance. The size of the ejection hole 32 of the nozzle plate 26 can be selected according to the target droplet size, but the diameter is preferably 2 μm or more and 40 μm or less.

  The ultrasonic irradiation in the buffer chamber 17 may be performed only when printing is performed by the head module 2, or may be continued even when printing is not performed by the head module 2. When performing ultrasonic irradiation, ultrasonic irradiation may be performed continuously or intermittently.

  The case where the temperature control means is provided only in the buffer chamber 17 has been described above. However, the present invention is not limited to this. For example, the temperature of the spacer dispersion liquid is measured by providing the temperature control means in the external filter 19. Based on the above, the spacer dispersion liquid after passing through the external filter 19 can be set to a set temperature by heating or cooling the external filter 19. The temperature control of the spacer dispersion liquid may be performed by either one of the buffer chamber 17 and the external filter 19 or by both.

  The above is a description of the case where the ejection at the ejection holes 32 is controlled by a piezo element system in which a piezo element is provided in the vicinity of the ejection holes 32. However, the ejection control method is not limited to this, and a bubble jet (registered trademark) is used. ) Method, thermal jet method and the like.

[Number of spacer particles discharged]
The printing apparatus 1 shown in FIGS. 1 and 2 printed a commercially available spacer dispersion solution, and evaluated the number of spacers in the discharged droplets.

  The spacer dispersion liquid is prepared by dispersing commercially available spacer particles produced for spacer dispersion in an alcohol-based mixed solvent and removing aggregates with a filter in advance. The system was 4.1 μm and the spacer particle concentration was adjusted to 0.1 wt%.

When the nozzle (ejection hole 32) diameter was 28 μm, the discharge droplet size was 20 pl, and the number of spacers in one droplet was 3.2 ± 0.2.
Furthermore, when the nozzle diameter was 23 μm, the ejection droplet size was 8 pl, and the number of spacers in one droplet was 2.0 ± 0.9.
From these results, it can be seen that the ejection droplet size and the number of spacers in the droplet can be controlled by changing the nozzle diameter.

[Discharge stability evaluation test]
When the spacer dispersion liquid is circulated in both the circulation path 50 and the head module 2 using the printing apparatus 1 shown in FIGS. 1 and 2 (Example 1), the spacer dispersion liquid is circulated only in the circulation path 50. When performing (Comparative Example 1) and when the spacer dispersion liquid is circulated in both the circulation path 50 and the head module 2, and at the same time, the spacer dispersion liquid stored in the buffer chamber 17 is irradiated with ultrasonic waves. For (Example 2), the spacer dispersion liquid was continuously discharged from the ejection holes 32, and the number of spacers in the droplets during the continuous discharge was evaluated.

  The results are shown in Table 1 below.

  As is apparent from Table 1 above, Comparative Example 1 in which the spacer dispersion liquid is not circulated in the head module 2 is the number of spacers from the initial 2.0 ± 0.9 to 1.5 ± 1.0 after 60 minutes. A decrease was observed. On the other hand, in Example 1 in which the spacer dispersion liquid was circulated in the head module 2, the number of spacers was reduced to 1.9 ± 0.9 in 60 minutes. Further, in Example 2 in which ultrasonic irradiation was performed during circulation in the head module 2, the effect of ejection stability was confirmed without change even after 60 minutes.

  After continuous ejection for 60 minutes, ultrasonic irradiation in the head module 2, circulation of the spacer dispersion liquid, and evaluation of the number of spacers after the flushing operation of the head module 2 were performed, and maintenance was performed even when there was no circulation in the head module 2. It returned to the initial 2.0 ± 0.9 by the operation.

  Thus, it can be seen that the discharge stability is improved by circulating the spacer dispersion liquid in the head module 2 and more preferably irradiating the spacer dispersion liquid in the head module 2 with ultrasonic waves.

FIG. 2 is a diagram illustrating an example of a printing apparatus according to the present invention. The figure explaining the head module of this invention An enlarged sectional view for explaining an example of a head body used in the present invention The figure explaining the other example of the printing apparatus of this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printing apparatus 2, 2 '... Head module 5 ... Storage system 10 ... Transport system 17 ... Buffer chamber 20 ... Head main body 21 ... Discharge chamber 22 ... Transport chamber 23 ... Inlet 24 ... ... Outlet 26 ... Nozzle plate 30 ... Internal filter 32 ... Injection hole 39 ... Spacer particles 41 ... Supply valve 42 ... Discharge valve 51 ... Supply system 52 ... Discharge system 53 ... Connection system

Claims (7)

An internal hollow head body;
A nozzle plate constituting one wall surface of the head body;
A transport system for transporting the spacer dispersion supplied from the storage system to the head body,
The nozzle plate is provided with ejection holes, and the spacer dispersion liquid transported into the head body is a head module configured to be ejected from the ejection holes,
The internal space of the head body is divided into a discharge chamber on the nozzle plate side and a transport chamber on the opposite side of the nozzle plate by an internal filter that is disposed inside the head main body and allows the spacer dispersion liquid to pass through.
A wall surface of the transport chamber is provided with an inlet port to which the spacer dispersion liquid is supplied, and an outlet port that is provided apart from the inlet port and discharges the spacer dispersion liquid.
The transport system is a head module having a pump for returning the liquid discharged from the discharge port to the inflow port.   The transport system has a discharge valve, and the discharge state in which the spacer dispersion liquid is discharged from the discharge port to the storage system from the circulation state by switching the discharge valve. The head module according to claim 1, wherein the head module is configured to be switched. Spacer particles are dispersed in the spacer dispersion,
Inside the internal filter, there is provided a passage having a diameter more than twice the diameter of the spacer particles and allowing the spacer dispersion to pass through,
The head module according to claim 1, wherein a diameter of the ejection hole is made larger than a diameter of the passage. A storage system in which the spacer dispersion is stored;
One or more head modules for discharging the spacer dispersion;
A supply system for connecting each head module to the storage system and supplying the spacer dispersion to each head module;
A discharge system for connecting each head module to the storage system and returning the spacer dispersion discharged from the head to the storage system;
Each head module has a supply valve that switches between allowing and stopping the supply of the spacer dispersion liquid,
When the supply valves are allowed, the spacer dispersion liquid is supplied from the supply system to the head modules.
A connection system for connecting the supply system and the discharge system, and when the supply valves are stopped, the spacer dispersion liquid does not pass through the head modules, but passes through the connection system and is discharged A printing device configured to return to the system. A printing apparatus according to claim 4, comprising the head module according to any one of claims 2 and 3.
In the state where the discharge valve is in the circulation state and the supply valve is in the stop state, the spacer dispersion liquid returns from the discharge port to the inlet, and returns to the discharge system without passing through the head module. Printing device configured to be performed simultaneously. A storage system in which the spacer dispersion is stored;
One or more head modules for discharging the spacer dispersion;
A supply system for connecting the head modules to the storage system;
A discharge system for connecting each head module to the storage system and returning the spacer dispersion discharged from the head module to the storage system;
Each of the head modules includes a hollow head body, a nozzle plate formed by one wall surface of the head body, a supply path for supplying the spacer dispersion liquid from the supply system to the head body, and a discharge from the head body. A discharge path for returning the spacer solution to the discharge system,
The spacer dispersion liquid supplied to the head main body is a printing apparatus configured to be discharged from an ejection hole provided in the nozzle plate,
The internal space of the head body is divided into a discharge chamber on the nozzle plate side and a transport chamber on the opposite side of the nozzle plate by an internal filter disposed inside the head body.
The wall surface of the transport chamber is provided with an inflow port to which the spacer dispersion liquid is supplied from the supply path, and a discharge port that is provided apart from the inflow port and returns the spacer dispersion liquid to the discharge path.
The supply path and the discharge path are connected to the inlet and the outlet, respectively.
The spacer dispersion liquid sent to the supply path passes through the transport chamber before being sent to the discharge path. The supply paths of the head modules are sequentially connected to the supply system along the direction in which the spacer solution flows,
Closing the supply valve of the upstream supply path connected to the supply system on the upstream side, and opening the supply valve of the downstream supply path connected to the supply system on the downstream side of the upstream supply path, the spacer The printing apparatus according to claim 6, wherein the dispersion liquid does not pass through the transport chamber connected to the upstream supply path but passes through the transport chamber connected to the downstream supply path.

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