JP5434024B2 - Liquid storage container and droplet coating apparatus - Google Patents

Description

  The present invention relates to a liquid storage container that stores a liquid having precipitated particles, and a droplet applying apparatus including the liquid container.

  Generally, a coating liquid (ink) in which particles such as pigments are uniformly dispersed in a solvent is used as a coating liquid used in a droplet coating apparatus such as an ink jet recording apparatus. Such an ink has a property that particles are settled due to a difference in specific gravity between the solvent and the particles when left for a long period of time or in a standby state. Due to the sedimentation of the particles, a difference in color density and variations in ink physical properties (viscosity, surface tension, specific gravity, etc.) occur between the sedimentation portion and the supernatant portion.

  For such sedimentation of particles, it has been studied to provide a stirring device in order to maintain a constant concentration and physical properties. For example, in Patent Document 1, as a method for redispersing precipitated particles, a magnetic stirrer is disposed at the bottom of the ink tank, and the stirring particles in the ink tank are rotated by rotating the magnetic stirrer to disperse the precipitated particles. It is disclosed.

  In Patent Document 2, the priority is set to be equal to other operations for the first few minutes when the effect of the stirring operation is high, and the printing operation or the head maintenance operation is not waited by lowering the priority for the remaining time. It has been proposed to be an objective.

  In recent years, with the increasing needs for high-speed printing, the line printing method (a method in which the droplet discharge unit is fixed during printing and the method that transports only the media) and the serial printing method (the droplet discharge unit during printing are used) It is desired to further increase the speed of the method of moving the media and transporting the media. For example, it has a feature that production efficiency can be increased by a droplet discharge method using an ink jet method described in Patent Document 3.

Japanese Patent Laid-Open No. 60-110458 JP 2008-1000047 A JP 2007-245086 A

  In Patent Document 1, although there is a description about dispersion of a pigment, there is no description about generation of bubbles accompanying the dispersion and a method for suppressing the bubbles. In the dispersion method of Patent Document 2, it is necessary to operate the supply valve mechanism when a printing operation or a head maintenance operation is performed while the stirring mechanism is operating, and the stirring operation is performed in the case of a stirring operation with a low priority. It is disclosed that the printing operation and the maintenance operation are performed while the operation is stopped, but when the printing operation increases as the speed increases, the agitation operation is not performed for a long period of time, and the sedimentation of particles is suppressed. Is difficult.

  In Patent Document 3, by circulating the coating liquid in the coating liquid supply path and stirring the ink in the liquid storage container (ink tank), it is possible to suppress sedimentation of particles even in inks typified by spacer beads. However, sufficient measures are not taken with respect to the generation of bubbles accompanying dispersion and the method of suppressing the bubbles.

  The object of the present invention is to eliminate such drawbacks of the prior art, uniformly disperse precipitated particles such as pigments in the liquid, and do not supply bubbles generated during agitation to the coating liquid supply path and droplet discharge section The object is to provide a storage container and a droplet applying apparatus.

The first means of the present invention for achieving the above object is to provide a liquid storage container for storing a liquid containing precipitated particles , along the bottom surface by the rotation of a stirrer in which the stored liquid is disposed in the storage container. It was stirred in a constant direction Te, and is characterized in the kite toward the liquid supply port of the liquid supply pipe for supplying a liquid to the droplet discharge unit on the downstream side of the stirring direction.

  The second means of the present invention is characterized in that, in the first means, the direction of the liquid supply port is linked in a range of, for example, about 80 ° to 100 ° with respect to the liquid container moving direction. It is.

According to a third means of the present invention, in the droplet applying apparatus having the liquid storage container of the first or second means, when the operation of ejecting a large amount of liquid from the droplet discharge section is executed, the liquid storage it is characterized in that supply many solutions than the channel volume to the droplet discharge unit from the container.

The fourth means of the present invention is characterized in that , in the third means, the stirring of the liquid in the liquid storage container is interrupted simultaneously with an operation command for discharging a larger amount of solution from the droplet discharge unit than during the printing operation. It is what.

  As a first means of the present invention, by setting the liquid supply port to the downstream side in the stirring direction with respect to stirring in a certain direction, settling of the precipitated particles in the liquid is prevented and the particle concentration in the liquid is kept constant. In addition, it is possible to reduce the supply of liquid containing excessive bubbles from the liquid supply port to the coating liquid supply pipe and the droplet discharge section. In a droplet applying apparatus typified by an ink jet recording apparatus, excessive bubbles in the liquid may interfere with the discharge of the liquid from the droplet discharge unit, but the occurrence of such non-discharge can be efficiently reduced.

  As a second means of the present invention, the direction of the liquid supply port is a direction perpendicular to the liquid container movement direction, so that even when the liquid container moves at high speed in the high speed serial printing method. The bubbles in the liquid can be prevented from entering the liquid supply path.

  As a third means of the present invention, the operation of ejecting a large amount of liquid from the droplet discharge section is performed by supplying a solution larger than the flow path volume from the liquid storage container to the droplet discharge section. Bubbles remaining inside can also be discharged from the droplet discharge section, and the occurrence of non-discharge can be reduced.

  As a fourth means of the present invention, the bubbles in the liquid in the liquid storage container are more than necessary by interrupting the agitation at the same time as the operation command for discharging a larger amount of solution from the droplet discharge unit than in the printing operation. Can be prevented and non-ejection of the coating liquid in the droplet ejection section can be suppressed.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of the entire droplet discharge apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic block diagram of the droplet discharge apparatus.

  First, a schematic configuration of the droplet discharge device will be described with reference to FIG. As shown in the figure, the droplet discharge apparatus is roughly divided into a function, and is composed of a pressure switching unit 1, a coating liquid supply circulation unit 2, a liquid storage unit 3, and a droplet discharge unit 4. The connection is as shown.

  The liquid storage unit 3 is installed at a position higher than the droplet discharge unit 4. The liquid storage unit 3 is equipped with two cartridges, a first cartridge 5a and a second cartridge 5b. The first cartridge 5a and the second cartridge 5b are individually replaceable (detachable) with respect to the apparatus main body. It has become. The first cartridge 5a and the second cartridge 5b are connected in parallel to the coating liquid supply circulation unit 2 and can be switched to each other.

  As shown in FIG. 1, each of the cartridges 5a and 5b has a main tank 6 for storing the coating liquid before discharge and a sub tank (coating liquid circulation buffer tank) 7 for collecting the coating liquid.

  A main tank pressurizing / depressurizing pipe 8 is connected to the main tank 6, which is connected to a main tank manifold 9 provided in the pressure switching unit 1 through the coating liquid supply circulation unit 2. The main tank manifold 9 is connected to a main tank pump 11 via a main tank pressure buffer 10. The main tank pressurizing / depressurizing pipe 8 exiting from the first cartridge 5a and the main tank pressurizing / depressurizing pipe 8 exiting from the second cartridge 5b are connected to the main tank switching unit comprising a three-way valve. A valve 12 is connected.

  An inter-tank transfer pipe 13 extends from the sub tank 7 toward the main tank 6, and an inter-tank transfer pump 14 is interposed in the middle.

  A sub tank pressurizing / depressurizing pipe 15 is connected to the sub tank 7, which is connected to a sub tank manifold 16 provided in the pressure switching unit 1 through the coating liquid supply circulation unit 2. The sub tank manifold 16 is connected to a sub tank pump 18 via a sub tank pressure buffer 17. The sub-tank manifold 16 is provided with an air introduction port 97, a flow rate adjustment valve 98, and an outside air intake filter 99, and can be opened and closed by the outside air intake valve 100.

  A sub-tank switching valve 19 comprising a three-way valve is provided at the junction between the sub-tank pressurizing / depressurizing pipe 15 coming out of the first cartridge 5a and the sub-tank pressurizing / depressurizing pipe 15 coming out of the second cartridge 5b. It is connected.

  A coating liquid supply pipe 20 extends from the main tank 6 toward the droplet discharge section 4. The coating liquid supply pipe 20 exits from the first cartridge 5 a and the coating liquid supply pipe 20 exits from the second cartridge 5 b. Is connected to a cartridge switching valve 21 composed of a three-way valve.

  A coating liquid recovery pipe 22 extends from the droplet discharge section 4 through the coating liquid supply circulation section 2 to the sub tank 7 side, and extends to the first cartridge 5a side and to the second cartridge 5b side. A coating liquid recovery switching valve 23 composed of a three-way valve is connected to a branch portion with the extending coating liquid recovery pipe 22.

  Four heads 24 a to 24 d are arranged in a straight line in the droplet discharge section 4, and each head 24 a to 24 d is connected in series by a head connection tube 39.

  A liquid level sensor 25 using ultrasonic waves is fixed to the upper part of the main tank 6, and the liquid level (remaining amount) of the coating liquid 26 in the main tank 6 is monitored. The main tank 6 and the sub tank 7 are provided with a stirrer 27 made of a magnetic material that rotates by applying an alternating magnetic field from the outside, and the number of rotations of the stirrer 27 can be adjusted appropriately by applying the alternating magnetic field. Due to the stirring action accompanying the rotation of the stirrer 27, the settling of particles in the coating liquid 26 is more reliably prevented.

  A cleaning liquid tank 29 is connected to the coating liquid supply circulation unit 2 via a cleaning liquid supply pipe 28, and a cleaning liquid 30 such as isopropyl alcohol is accommodated in the tank. The liquid level (remaining amount) of the cleaning liquid 30 in the cleaning liquid tank 29 is monitored by a liquid level sensor 31.

  A waste liquid pipe 32 is connected in the middle of the coating liquid recovery pipe 22, and the waste liquid pipe 32 extends to the waste liquid tank 33. The amount of waste liquid in the tank is monitored by the liquid level sensor 34.

  The pressurized gas 35 made of nitrogen or air is supplied to the main tank manifold 9, the sub tank manifold 16, the coating liquid supply pipe 20 and the cleaning liquid tank 29 through the pressurized manifold 36 through the pressurized gas pipes 37. It has become so.

  A coating liquid / cleaning liquid / pressurized gas switching valve 38 composed of a three-way valve is installed at a joint portion of the pressurized gas pipe 37 with the coating liquid supply pipe 20. Further, a cleaning liquid / pressurized gas switching valve 40 comprising a three-way valve is installed at the junction between the pressurized gas pipe 37 and the cleaning liquid supply pipe 28. A pressure sensor 41 is attached to each of the main tank manifold 9, the sub tank manifold 16, and the pressurizing manifold 36.

  A coating liquid / waste liquid switching valve 42 composed of a three-way valve is installed at a joint portion between the coating liquid supply pipe 20 and the waste liquid pipe 32 exiting from the coating liquid supply switching valve 21. Between the coating liquid / waste liquid switching valve 42 on the coating liquid supply pipe 20 and the droplet discharge section 4, a first cutoff valve 43 comprising a two-way valve is installed. The coating liquid recovery pipe 22 exiting from the droplet discharge section 4 extends to the waste liquid side tube 44 extending toward the waste liquid pipe 32 and the coating liquid recovery switching valve 23 near the junction with the waste liquid pipe 32. It branches into two with the collection side tube 46. Then, a second shut-off valve 46 consisting of a two-way valve is installed on the waste liquid side pipe body 44, and a third shut-off valve 47 consisting of a two-way valve is installed on the recovery side pipe body 46, as shown in the figure. The coating liquid recovery pipe 22 that has come out of the droplet discharge unit 4 is connected between the second cutoff valve 46 and the third cutoff valve 47.

  As shown in the figure, in both the first cartridge 5a and the second cartridge 5b, the main tank 6 → the coating liquid supply pipe 20 → the heads 24a to 24d → the coating liquid recovery pipe 22 → the sub tank 7 → the inter-tank transfer pipe 13 (for inter-tank transfer A circulation path for the coating liquid 26 is formed by the pump 14).

  Both the first cartridge 5a and the second cartridge 5b are replaceable with respect to the apparatus main body, 49a in the figure is a connecting portion between the main tank 6 and the coating liquid supply pipe 20, and 49b is the main tank 6 and the main tank. 49c is a connection part between the main tank 6 and the outlet side of the tank transfer pipe 13, 49d is a connection part between the sub tank 7 and the inlet side of the tank transfer pipe 13, 49e. Is a connecting portion between the sub tank 7 and the sub tank pressurizing / depressurizing tube 15, and 49 f is a connecting portion between the sub tank 7 and the coating liquid recovery tube 22. In these connection portions 49a to 49f, the cartridges 5a and 5b are connected to the apparatus main body in a replaceable manner. A predetermined amount of coating liquid 26 is injected into the main tank 6 and the sub tank 7 of the first cartridge 5a and the second cartridge 5b.

Next, various operations of the droplet discharge device will be described. First, the case where the coating liquid 26 is discharged using the first cartridge 5a will be described.
(Coating liquid filling operation)
In the state where the first cartridge 5a is mounted on the droplet discharge device, air exists in the coating liquid supply pipe 20, the heads 24a to 24d, the head connection pipe 39, the coating liquid recovery pipe 22, and the like. In order to eliminate air, the air is first replaced with the cleaning liquid 30.

  Since air still remains in the coating liquid supply pipe 20 between the main tank 6 and the switching valve 38, the A side of the switching valve 38 is opened and the B side is closed, and the switching valve 21 is left as it is. The A side of the valve 42 is closed and the B side is opened, and the shutoff valve 43 is closed. Further, the A side of the switching valve 12 is opened and the B side is closed.

  The pressurized gas 35 is supplied into the main tank 6 through the pressurized gas pipe 37, the main tank manifold 9, and the main tank pressurizing / depressurizing pipe 8 to increase the internal pressure, and the coating liquid 26 is applied by the internal pressure. By flowing through the supply pipe 20 and the waste liquid pipe 32, the cleaning liquid 30 is filled in the path between the ink tank and the switching valve 38.

  Therefore, the A side of the switching valve 40 is opened and the B side is closed, the A side of the switching valve 38 is closed and the B side is opened, the A side of the switching valve 21 is opened and the B side is closed, and the A side of the switching valve 42 is opened. The side is closed, the shutoff valve 43 is opened, the shutoff valve 46 is opened, and the shutoff valve 47 is closed.

  The pressurized gas 35 is supplied into the cleaning liquid tank 29 through the pressurized gas pipe 37 to increase the internal pressure, and the cleaning liquid 30 in the cleaning liquid tank 29 is supplied to the cleaning liquid supply pipe 28 and a part of the pressurized gas pipe 37 by the internal pressure. The cleaning liquid 30 is replaced with the cleaning liquid 30 by flowing through the coating liquid supply pipe 20, the heads 24 a to 24 d, the head connection pipe 39, a part of the coating liquid recovery pipe 22, and the waste liquid pipe 32. By circulating the cleaning liquid 30 for a predetermined time, the circulation path including the droplet discharge unit 4 is filled with the cleaning liquid.

Next, the A side of the switching valve 42 is opened, the B side is closed, and the shutoff valve 43 is opened. The pressurized gas 35 is supplied into the main tank 6 to increase the internal pressure, and the coating liquid 26 is supplied to the coating liquid supply pipe 20, the heads 24 a to 24 d, the head connection pipe 39, and a part of the coating liquid collection pipe 22 by the internal pressure. Then, the cleaning liquid 30 is replaced with the coating liquid 26 by flowing through the waste liquid pipe 32. Further, the shut-off valve 46 is closed, the shut-off valve 47 is opened, and the coating liquid 26 is pumped into the collection-side pipe body 45 and the coating liquid collection pipe 22 extending to the sub tank 7 ahead. Thereby, the filling operation of the coating liquid 26 is finished, and the operation of discharging the coating liquid 26 is continued.
(Coating solution discharge operation)
As described above, the liquid storage unit 3 is installed at a position higher than the droplet discharge unit 4, and a water head difference is generated between the two. In the present invention, by utilizing this water head difference, the coating liquid 26 is always circulated through the circulation path even when the coating liquid 26 is discharged from the recording head 4 to suppress sedimentation of the coating liquid components.

  However, if the liquid storage unit 3 is only installed at a position higher than the droplet discharge unit 4, the meniscus at the head orifice cannot be maintained well due to the effect of the water head difference, and liquid leakage occurs as in the prior art. Produce. Therefore, in the present invention, the inside of the main tank 6 and the sub-tank 7 are in a reduced pressure state so as to meet the condition that the coating liquid 26 can circulate while maintaining a good meniscus at the head orifice.

  Specifically, the A side of the coating liquid recovery switching valve 23 is opened, the B side is closed, the second cutoff valve 46 is closed, the third cutoff valve 47 is opened, the main tank switching valve 12 and the sub tank switching valve 19. Open the A side and close the B side. Then, the main tank pump 11 and the sub tank pump 18 are driven to reduce the pressure in the main tank 6 and the sub tank 7 through the main tank pressurizing / depressurizing pipe 8 and the sub tank pressurizing / depressurizing pipe 15, respectively. The internal pressure of the sub tank 7 is controlled by the pressure switching unit 1 so as to be always lower than the internal pressure of the main tank 6, and the pressure difference between them is always kept constant even if the amount of the coating liquid 26 changes. The remaining amount of the coating liquid 26 can be detected by the liquid level sensor 25.

  The step H between the discharge surface of the head 24 and the bottom surface of the main tank 6 is about 700 mm, the internal pressure of the main tank 6 is about −8 kPa, the internal pressure of the sub tank 7 is about −11 kPa, and the pressure difference between the tanks 6 and 7 is about 3 kPa. Is set to The internal pressure of the main tank 6 varies within about ± 0.5 kPa depending on the amount of the coating liquid 26 in the main tank 6 and is controlled so that the internal pressure of the sub tank 7 becomes constant. The coating liquid 26 is smoothly circulated by the pressure difference between the main tank 6 and the sub tank 7.

  The internal pressure of the main tank sets the operation of the inter-tank transfer pump so that the transfer amount of the inter-tank transfer pump 14 increases with respect to the ink amount consumed by ink discharge and ink circulation. The internal pressure of the main tank during ink circulation gradually changes to a positive pressure. When the internal pressure of the main tank changes outside the range on the positive pressure side, the pump 11 is operated so that the internal pressure of the main tank is within the range. Control to be.

  In this embodiment, as shown in FIG. 1, an air introduction port 97 is provided by an outside air intake valve 100 in the path between the sub tank and the negative pressure maintaining pressure buffer 17, and the internal pressure of the sub tank is relative to the recovered ink amount. Thus, the operation of the inter-tank transfer pump is set so that the transfer amount of the inter-tank transfer pump 14 increases. The amount of outside air taken in from the air introduction port 97 is set to be between the transfer amount of the inter-tank transfer pump 14 and the suction amount of the sub-tank pump 18. As a result, the internal pressure of the sub-tank during ink circulation gradually changes to a positive pressure. When the internal pressure of the sub-tank changes outside the range on the positive pressure side, the pump 18 is operated and the internal pressure of the sub-tank falls within the range. Control to be.

  The amount of outside air taken in from the atmosphere introduction port 97 is adjusted by a flow rate control valve 98. The amount of outside air taken in from the air inlet is adjusted to an amount in the range of 5 to 95% with respect to the suction amount of the pump 41 in the ink circulation state, so that the control of the internal pressure of the sub tank is adjusted with high accuracy. Is possible.

  The atmosphere introduction port 97 is provided with an outside air intake filter 99 having a pore size smaller than the smallest pore of the atmosphere introduction path so that the amount of outside air taken in due to the influence of dust mixed in the taken outside air changes. prevent.

  In this way, by controlling the pressure, when the transfer amount of the inter-tank transfer pump is large, it is possible to prevent the problem of gradually becoming negative pressure in the circulation state, and to adjust the control of the internal pressure with high accuracy.

  The coating liquid 26 in the main tank 6 is supplied to the droplet discharge section 4 through the coating liquid supply pipe 20 due to the water head difference, flows into the pressure chambers of the heads 24, and drops from the orifice by driving the piezoelectric vibrator. And discharged onto a predetermined position of the substrate 48.

  The coating liquid 26 that has not been discharged flows to the next head 24 and a part thereof is discharged, and the coating liquid 26 that remains without being finally discharged is sent to the sub tank 7 through the coating liquid recovery pipe 22. The coating liquid 26 in the sub tank 7 is returned to the main tank 6 through the inter-tank transfer pipe 13 by driving the inter-tank transfer pump 14. By the rotation control of the inter-tank transfer pump 14, the liquid level difference H between the main tank 6 and the sub tank 7 is always maintained appropriately. When the coating liquid 26 is not ejected, the piezoelectric vibrator of the head 24 is not driven, so that the coating liquid 26 only passes through the heads 24a to 24d.

As described above, the coating liquid 26 circulates both at the time of ejection and at the time of non-ejection, and is always in a fluid state. Furthermore, in this figure, since the stirrer 27 is rotating in the main tank 6 and the sub-tank 7, the sedimentation of particles is suppressed.
(Cartridge switching operation)
Next, the switching operation from the first cartridge 5a to the second cartridge 5b will be described. When the liquid level sensor 25 detects that the liquid level of the main tank 6 on the first cartridge 5a side has fallen below a predetermined position, it is determined that the coating liquid 26 on the first cartridge 5a side has been consumed.

  When the coating liquid 26 of the first cartridge 5a and the second cartridge 5b has the same composition, the coating liquid 26 is already filled in the circulation path including the droplet discharge unit 4, but the second cartridge 5b side has Air still remains in the coating liquid supply pipe 20b from the main tank 6 to the switching valve 38b and the path from the switching valve 23 to the sub tank 7b.

  Therefore, the A side of the switching valves 12, 19, 23, 42 is closed, the B side is opened, the A side of the switching valve 38 is opened, and the B side is closed. The pressurized gas 35 is supplied into the main tank 6b through the pressurized gas pipe 37, the main tank manifold 9, and the main tank pressurizing / depressurizing pipe 8 to increase the internal pressure, and the coating liquid 26 is applied by the internal pressure. By circulating through the liquid supply pipe 20b and the waste liquid pipe 32, the air in the coating liquid supply pipe 20b from the main tank 6 to the switching valve 38b is discharged. Thereafter, the A side of the switching valve 42 is opened, the B side is closed, and the pressure is fed to the path from the switching valve 23 to the sub tank 7b. This completes the cartridge switching operation.

  Since the discharge operation of the coating liquid 26 is the same as that in the case of the first cartridge 5a, a duplicate description is omitted.

  When the composition of the coating liquid 26 is different between the first cartridge 5a and the second cartridge 5b, for example, the type of the liquid crystal display to be manufactured is changed, and accordingly the diameter of the spacer particles (beads) in the coating liquid 26 is different. Since the circulation channel including the droplet discharge section 4 is filled with the previous type of coating liquid 26a, it must be completely eliminated.

  Therefore, first, the A side of the switching valve 38 is closed and the B side is opened, the A side of the switching valve 21 is opened and the B side is closed, the A side of the switching valve 42 is opened and the B side is closed, and the first cutoff valve 43 and the third cutoff valve are closed. The valve 47 is opened, the second shutoff valve 46 is closed, the A side of the switching valve 23 is opened, and the B side is closed. Then, by closing the A side of the switching valve 40 and opening the B side, the pressurized gas 35 is pumped to the coating liquid supply pipe 20 through the pressurized gas pipe 37. As a result, the coating liquid supply pipe 20 after the switching valve 38, the heads 24a to 24d, the head connection pipe 39, and the coating liquid 26a remaining in the coating liquid collection pipe 22 up to the sub tank 7 of the first cartridge 5a are transferred to the sub tank 7. Discharged.

  Next, the valves other than the switching valve 40 are in the same state as when the coating liquid 26a is discharged, the A side of the switching valve 40 is opened, the B side is closed, and this time the cleaning liquid 30 is pumped. As a result, the coating liquid supply pipe 20, the heads 24a to 24d, the head connection pipe 39, and the coating liquid collection pipe 22 up to the sub tank 7 of the first cartridge 5a are washed, and the waste liquid is discharged to the sub tank 7. The When the type of the coating liquid 26 is changed as described above, the sub tank 7 of the cartridge 5 used before that is used as a waste liquid tank.

  Thus, after the discharge and cleaning of the coating liquid 26a in the circulation channel used so far are completed, the A side of the switching valve 38 on the first cartridge 5a side is closed and the B side is opened, and the second cartridge 5b is opened. The A side of the switching valve 38 on the side is opened, the B side is closed, the A side of the switching valve 21 is closed, the B side is opened, the A side of the switching valve 23 is closed, and the B side is opened.

By this valve operation, the circulation flow path including the droplet discharge section 4 is connected to the second cartridge 5b side, and in this state, the coating liquid 26b is filled on the second cartridge 5b side. Since the discharge operation of the coating liquid 26b is the same as described above, a duplicate description is omitted.
(Recovery operation of defective nozzle by suction purge)
Next, the recovery operation of the ejection failure nozzle by the suction and suction purge from the nozzle of the recording head will be described.

If the ejection failure nozzle does not recover even after performing the ejection inspection, a nozzle suction cap (not shown) is pressed against each of the heads 24a to 24d to remove internal bubbles, dust, aggregates of pigment, and the like.
(Recovery operation for defective nozzles by pressure purge)
If the ejection failure nozzle does not recover even after performing the recovery operation for the ejection failure nozzle by the suction purge, perform the pressurization operation from the main tank side to the nozzle of the recording head, and the recovery operation for the ejection failure nozzle by the pressure purge. Do.

The A side of the switching valve 42 is opened, the B side is closed, and the shutoff valves 46 and 47 are closed. The pressurized gas 35 is supplied into the main tank 6 to increase the internal pressure, and the coating liquid 26 is supplied to the coating liquid supply pipe 20, the heads 24 a to 24 d, and the head connection pipe 39 by the internal pressure. After a certain period of time has elapsed, the shutoff valve 47 is opened, and the coating liquid 26 is pumped into the collection side pipe body 45 and the coating liquid collection pipe 22 extending to the sub-tank 7 ahead.
(Recovery operation of defective nozzle by cleaning liquid pressure purge)
Next, a recovery operation for a stubborn defective discharge nozzle will be described. If the defective nozzle does not recover even after performing the ejection inspection after repeating the suction operation of the nozzle of the recording head and the pressurization operation from the main tank side multiple times, the cleaning liquid pressure purge is performed as follows. Perform recovery operation for defective nozzles.

  In a state where a stubborn ejection failure nozzle is generated, ink is filled in the coating liquid pipe 20, the heads 24a to 24d, the head connection pipe 39, the coating liquid collection pipe 22, and the like. To do.

  Therefore, the A side of the switching valve 40 is opened and the B side is closed, the A side of the switching valve 38 is closed and the B side is opened, the A side of the switching valve 21 is opened and the B side is closed, and the A side of the switching valve 42 is opened. The side is closed, the shutoff valve 43 is opened, the shutoff valve 46 is opened, and the shutoff valve 47 is closed. These valve opening / closing operations may be performed simultaneously using electromagnetic valves as valve opening / closing means.

  The pressurized gas 35 is supplied into the cleaning liquid tank 29 through the pressurized gas pipe 37 to increase the internal pressure, and the internal pressure increases the cleaning liquid 30 in the cleaning liquid tank 29 to the cleaning liquid supply pipe 28 and the pressurized gas pipe 37. A part of the coating liquid supply pipe 20, the heads 24 a to 24 d, the head connection pipe 39, a part of the coating liquid recovery pipe 22, and the waste liquid pipe 32 are allowed to flow, whereby the coating liquid in the meantime is replaced with the cleaning liquid 30. By circulating the cleaning liquid 30 for a predetermined time, the circulation path including the droplet discharge unit 4 is filled with the cleaning liquid.

  At this time, the opening and closing of the shutoff valve 43 is repeated, the opening and closing time of the shielding valve is set within 10 seconds, and the closing time is set to 1 second or more, so that the internal pressure in the cleaning liquid tank 29 is not reduced. In addition, the flow rate of the cleaning liquid can be reduced. As a result, the mixed liquid of the coating liquid and the cleaning liquid accumulated on the nozzle surfaces of the heads 24a to 24d overflows from the nozzle surfaces and wraps around the side surfaces of the heads. Can be prevented. Since it is not necessary to reduce the internal pressure in the cleaning liquid tank 29, high cleaning performance can be maintained.

  Further, by driving the head when replacing the coating liquid with the cleaning liquid, the action of discharging bubbles and foreign matters becomes stronger, and the recoverability of the non-ejection nozzle is improved.

  After passing the cleaning liquid for a predetermined time, the A side of the switching valve 42 is opened, the B side is closed, and the shutoff valve 43 is opened. The pressurized gas 35 is supplied into the main tank 6 to increase the internal pressure, and the coating liquid 26 is supplied to the coating liquid supply pipe 20, the heads 24 a to 24 d, the head connection pipe 39, and a part of the coating liquid collection pipe 22 by the internal pressure. Then, the cleaning liquid 30 is replaced with the coating liquid 26 by flowing through the waste liquid pipe 32. Further, the shut-off valve 46 is closed, the shut-off valve 47 is opened, and the coating liquid 26 is pumped into the collection-side pipe body 45 and the coating liquid collection pipe 22 extending to the sub tank 7 ahead. As a result, the refilling operation of the coating liquid 26 is finished, and then the operation of discharging the coating liquid 26 is continued.

  3 and 4 are a front view and a side view of the droplet discharge device according to the embodiment of the present invention.

  As shown in these drawings, two X-axis linear rails 52 extending in parallel are laid and fixed on the coating stage 51, and two X-axis linear guides 53 are mounted thereon. A table 55 is fixed on the X-axis linear guide 53 via a stage base 54.

  On the table 55, a substrate 48 for applying a coating liquid is placed and fixed at a predetermined position on the table 55 by positioning means (not shown) such as an air suction mechanism.

  A support column 56 extends upward from the left and right side surfaces of the coating stage 51, and a guide support member 57 is installed on the upper end of the support column 56. Two Y-axis linear guides 58 extending in parallel are fixed to the front surface of the guide support member 57 in the horizontal direction, and a Y-axis base 59 is slidably supported by the Y-axis linear guide 58. Further, a Z-axis base 60 extending in the vertical direction is fixed on the Y-axis base 59, and a Z-axis linear guide 61 (see FIG. 3) is slidably supported on the Z-axis base 60.

  A coating liquid discharge mechanism 62 is mounted on the Y-axis base 59 and the Z-axis base 60 as shown in FIG. The coating liquid supply box 63 in the coating liquid discharge mechanism 62 is mounted on the Y-axis base 59, and the coating liquid supply box 63 has the coating liquid circulation supply unit 2 and the liquid storage unit 3 as shown in FIG. doing. In the present embodiment, two sets of the main tank 6 and the sub-tank 7 are mounted as the liquid storage unit 3, but one set of the set may be mounted. On the other hand, the droplet discharge section 4 in the coating liquid discharge mechanism 62 is mounted on the Z-axis linear guide 61 (Z-axis base 60) via a head block 64.

  The table 55 on which the substrate 48 is mounted reciprocates on the X-axis linear rail 52 using, for example, a linear motor (not shown) as a drive source. The Y-axis base 59 on which the Z-axis base 60 is mounted reciprocates on the Y-axis linear guide 58 using, for example, a linear motor (not shown) as a drive source. The Z-axis linear guide 61 on which the droplet discharge unit 4 is mounted reciprocates on the Z-axis base 60 using, for example, a linear motor (not shown) as a drive source.

  As shown in these drawings, the coating liquid supply box 63 (the coating liquid circulation supply unit 2 and the liquid storage unit 3) is installed at a position higher than the droplet discharge unit 4, and therefore the liquid storage unit. 3, the coating liquid is naturally supplied into the droplet discharge section 4 through the coating liquid circulation supply section 2 through the coating liquid supply pipe (for example, a flexible tube), and the coating liquid in the droplet discharge section 4 is A pressurized state is always obtained by utilizing the liquid level difference with the liquid storage unit 3. For this reason, since there is a possibility that the coating liquid leaks in the droplet discharge section 4, the inside of the liquid storage section 3 is controlled to a reduced pressure state by the pressure switching section 1 (not shown).

  The distance between the droplet discharge unit 4 and the substrate 48 is appropriately set by adjusting the position of the Z-axis linear guide 61 on the Z-axis base 60. Then, while the table 55 on which the substrate 48 is mounted is reciprocated, the coating liquid is discharged as a droplet from the droplet discharge section 4 to a predetermined position on the substrate 48 at an initially set discharge timing.

When a droplet is landed at a required location by one reciprocation of the substrate 48, the coating liquid discharge mechanism 62 moves to the next coating area on the Y axis. By repeating these operations, droplets are landed on the entire surface of the substrate 48.
(Liquid container)
FIG. 5 is a schematic view of a liquid container according to the present invention, which will be specifically described below.
A white arrow indicates a stirring direction, and a black arrow indicates a supply direction of the coating liquid. By making these two opposite directions (the liquid supply port is directed downstream in the stirring direction), it is possible to prevent bubbles generated by stirring from being supplied from the coating liquid supply pipe 20 to the droplet discharge unit 4. Can do. The coating liquid supply pipe 20 can be processed in the vicinity of the bottom of the liquid storage unit 3 and the end face of the pipe into an oblique shape to further reduce the mixing of bubbles.

  The material of the container of the liquid storage unit 3 is not particularly specified, but those that are resistant to the liquid to be stored and can maintain airtightness are useful. Specifically, a plastic container such as a metal, glass, or Teflon (registered trademark) is used.

  Further, the shape of the container is not particularly limited as long as the liquid does not stay at the time of stirring, but if it is cylindrical, stable stirring and dispersion can be performed.

  The material of the coating liquid supply pipe 20 is not particularly defined, but those that are resistant to the liquid to be stored and can maintain airtightness are useful. Specifically, a tube having liquid resistance such as PFA, PTFE, PP or the like is used.

  The liquid stirring method includes a method of shaking the entire liquid container, a method using a stirrer, a method using ultrasonic irradiation, a method using a stirrer and a magnetic stirrer, and any one of them may be used. Two or more may be combined. In particular, the method using a stirrer and the method using a stirrer and a magnetic stirrer are particularly effective because they can be uniformly stirred and dispersed even when particles are precipitated by standing for a long period of time. .

  An example of a magnetic stirrer will be specifically described below. Made by ASONE; High-power stirrer REMIX, RP-1D, High-function high-power stirrer, ML-102, Ferromagnetic magnetic stirrer, HS-4SP, High-power stirrer, HS-100, manufactured by Nisshinka; Super-ferromagnetic stirrer SW -Use a magnetic stirrer such as RS077D.

  Specific examples of the stirrer will be described below. Made by Isis; Teflon (registered trademark) HP rotor taper type CMH2930, Teflon (registered trademark) HP rotor taper type CMH2925, Teflon (registered trademark) HP rotor cylinder type CMH2930, Teflon (registered trademark) HP rotor cylinder type CMH2925 It is better to use a rotor such as

  In addition, when using a stirrer, normal stirring may not be performed due to jumping, so by performing intermittent operation, the stirrer is returned to the center when stopped and the center of the magnetic stirrer is restarted when stirring is started again. It is possible to perform normal stirring. The intermittent operation is preferably performed by, for example, stirring for 15 to 60 seconds, stopping for 5 to 15 seconds, or the like, and the intermittent time may be a combination in any range, and can be appropriately changed depending on the types of particles and coating liquid. Furthermore, if the rotational speed is changed in accordance with the amount of the coating solution, it is possible to achieve both stable dispersion of particles and prevention of bubble entrainment.

  FIG. 6 is a sequence flow diagram when the stirring operation is stopped in the present invention. When each start command of an operation command filling operation, a switching operation, and a purge operation (aspiration purge, pressure purge, cleaning liquid pressure purge) for issuing a larger amount of solution from the droplet discharge unit 4 than during the printing operation is issued, The stirring operation is stopped. Next, a filling operation, a switching operation, and a purge operation are started. Before each operation starts, the valve is opened and closed and the pressure is adjusted. During this time, bubbles near the supply port of the coating liquid supply pipe 20 move upward, so that the bubbles are supplied into the coating liquid supply pipe 20. It becomes difficult to be done.

  It should be noted that “the switching valve 42 is opened on the A side and the B side is closed, and the shutoff valves 46 and 47 are further closed, and then the pressurized gas 35 is supplied into the main tank 6 to increase the internal pressure. Even when fine bubbles are included in the coating liquid supply pipe 20 by extending the time for supplying the coating liquid 26 to the coating liquid supply pipe 20, the heads 24a to 24d, and the head connection pipe 39 by the internal pressure. It is possible to reduce the retention of bubbles in the droplet discharge unit 4.

  In addition, after each of the filling operation, the switching operation, and the purge operation is completed, the stirring operation is started to uniformly disperse the particles.

  FIG. 7 is a layout view of the moving direction of the liquid container and the coating liquid supply pipe in the present invention. By directing the liquid supply port of the coating liquid supply pipe 20 in a direction perpendicular to the liquid container movement direction (Y-axis direction) (in the range of 80 ° to 100 ° with respect to the X-axis direction and the Y-axis direction), Even if the liquid storage container is moved at a high speed, bubbles in the liquid can be prevented from entering the coating liquid supply pipe 20.

  The present invention relates to the production of electroluminescence, the production of printed wiring boards on which ink containing titanium oxide particles is printed, the production of multilayer ceramic electronic components and high-frequency components using high-concentration inks for electronic components that tend to settle and aggregate. The present invention can be applied in the technical field of dispersion of spacer particles in the manufacture of electronic components such as electronic components and liquid crystal display devices. Furthermore, the present invention can be applied to an ink jet recording apparatus using a coating liquid having an organic pigment or an inorganic pigment.

1 is a system diagram of a droplet discharge device according to an embodiment of the present invention. It is a schematic block diagram of the droplet discharge device. It is a front view of the droplet discharge device concerning an embodiment of the present invention. It is a side view of the droplet discharge device. It is the schematic of the liquid storage container in this invention. It is a sequence flow figure at the time of stirring operation stop in the present invention. FIG. 4 is a diagram illustrating the moving direction of the liquid container and the arrangement of the coating liquid supply pipe in the present invention.

Explanation of symbols

  1: pressure switching unit, 2: coating liquid circulation supply unit, 3: liquid storage unit, 4: droplet discharge unit, 5: cartridge, 5a: first cartridge, 5b: second cartridge, 6: main tank, 7: Sub tank, 8: Main tank pressurization / decompression pipe, 9: Main tank manifold, 10: Main tank buffer, 11: Main tank pump, 12: Main tank switching valve, 13: Inter-tank transfer pipe, 14 : Tank transfer pump, 15: Sub tank pressurization / decompression pipe, 16: Sub tank manifold, 17: Sub tank buffer, 18: Sub tank pump, 19: Sub tank switching valve, 20: Coating liquid supply pipe, 21 : Coating liquid supply pipe switching valve, 22: coating liquid recovery pipe, 23: coating liquid recovery pipe switching valve, 24a to 24d: head, 25: liquid level sensor, 26: coating liquid, 27 Stirrer 28: Cleaning liquid supply pipe 29: Cleaning liquid tank 30: Cleaning liquid 31: Liquid level sensor 32: Waste liquid pipe 33: Waste liquid tank 34: Liquid level sensor 35: Pressurized gas 36: For pressurization Manifold 37: Pipe for pressurized gas 38: Coating liquid / cleaning liquid / pressurized gas switching valve 39: Head connecting pipe 40: Cleaning liquid / pressurizing gas switching valve 41: Pressure sensor 42: Coating liquid / waste liquid Switching valve, 43: first shutoff valve, 44: waste liquid side pipe body, 45: recovery side pipe body, 46: second shutoff valve, 47: second shutoff valve, 48: substrate, 49a to 49f: connection part, 51 : Coating stage, 52: X axis linear rail, 53: X axis linear guide, 54: stage base, 55: table, 56: support, 57: guide support member, 58: Y axis linear guide, 59: Y axis base, 60: Z-axis base, 61: Z-axis Rini Guide, 62: coating liquid discharge mechanism, 63: coating liquid supply box, 64: head block, 97: air inlet 98: flow control valve, 99: outside air intake filter, 100: ambient air intake valve.

Claims (4)

In a liquid storage container for storing a liquid containing settled particles, the stored liquid is stirred in a certain direction along the bottom surface by rotation of a stirrer disposed in the liquid storage container, and the liquid is supplied to a droplet discharge unit. liquid container, wherein the kite toward the liquid supply port which supplies the liquid supply pipe on the downstream side of the stirring direction. The liquid container according to claim 1, wherein the direction of the liquid supply port is linked to the moving direction of the liquid container. In the liquid drop application device provided with the liquid container according to claim 1 or 2 ,
When a droplet applying apparatus and supplying more solution than the channel volume to the droplet discharge unit from said liquid container for performing an operation to issue a large amount of liquid from the droplet ejecting section . The droplet applying apparatus according to claim 3 .
The liquid droplet applying apparatus characterized by interrupting the stirring of the liquid in the liquid container at the same time as an operation command for ejecting a larger amount of solution from the liquid droplet discharging unit than during a printing operation.

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