The present invention relates to an apparatus and method for manufacturing liquid containing fine bubbles, particularly, ultrafine bubbles with a diameter of less than 1.0 μm.
In recent years, techniques of applying the characteristics of fine bubbles such as microbubbles with a microscale diameter and nanobubbles with a nanoscale diameter have been developed. In particular, the benefit of ultrafine bubbles (hereinafter also referred to as “UFBs”) with a diameter of less than 1.0 μm has been confirmed in various fields, and there is an increasing need for liquid containing UFBs with a high purity.
PTL 1 discloses an apparatus that generates fine bubbles by subjecting gas to pressure dissolution by means of a pressure dissolution method to generate pressurized liquid and emitting a jet of the pressurized liquid from a nozzle. PTL 2 discloses an apparatus that generates fine bubbles by repeating diversion and confluence of a liquid-gas mixture by means of a mixing unit.
PTL 1: Japanese Patent Laid-Open No. 6118544
PTL 2: Japanese Patent Laid-Open No. 4456176
However, if liquid containing UFBs is manufactured by using PTL 1 or PTL 2, there are also generated a large number of millibubbles with a milliscale diameter and microbubbles with a microscale diameter. For this reason, to increase a purity of UFBs, it is needed to leave the bubble-containing liquid after the manufacture and wait for the millibubbles and microbubbles to disappear by floating in the air with buoyancy or by collapsing in the water. However, it is confirmed that also the UFBs themselves gradually disappear by being mixed with the millibubbles and microbubbles.
Furthermore, in the apparatus disclosed in PTL 1, liquid needs to have a high pressure between 0.5 and 0.6 MPa, and in the apparatus disclosed in PTL 2, liquid needs to have a high pressure of about 30 atm, where flow paths are also complicated. In other words, to manufacture a UFB-containing liquid by using PTL 1 or PTL 2, a large-scale complex apparatus having a large power consumption is required, and a long time is required for obtaining a UFB-containing liquid having a high purity.
The present invention has been made to solve the above problem. Accordingly, an object of the present invention is to provide a UFB-containing liquid manufacturing apparatus having a relatively small and simple configuration and capable of manufacturing a UFB-containing liquid having a high purity in a short period of time, and a method therefor.
Accordingly, the present invention is characterized by including a liquid ejecting unit having a thermal energy generating element, a flow path for leading liquid to the thermal energy generating element, a driving unit configured to drive the thermal energy generating element and cause film boiling in liquid led to the flow path, and an ejection opening for ejecting liquid containing ultrafine bubbles generated by the film boiling and a collecting unit configured to collect liquid ejected from the ejection opening.
According to the present invention, with a relatively small and simple configuration, it is possible to manufacture a UFB-containing liquid having a high purity in a short period of time.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
A protective layer 206 composed of SiN, SiO, or the like is formed so as to cover the wiring 205, the resistive layer 204, and the interlayer film 203. Furthermore, on the surface of the protective layer 206 in and around an area corresponding to a heat acting portion 208, an anti-cavitation film 207 is formed to protect the protective layer 206 from chemical and physical impact on the heat acting portion 208. For the anti-cavitation film 207, metal selected from Ta, Fe, Ni, Cr, Ru, Zr, Ir, or the like is used.
In such a configuration, if a voltage is applied across both ends of the wiring 205 to pass a current through the wiring 205, the current passes through the resistive layer 204 in an area not having the wiring 205, and the resistive layer 204 is heated. That is, the area not having the wiring 205, corresponding to the heat acting portion 208, serves as a thermal energy generating element 208 on the heating resistor substrate 200.
When the heater 208 abruptly generates heat by the application of a voltage, a bubble 920 is generated by film boiling in the liquid that is in contact with the heater 208. The bubble 920 grows as a temperature of the surface of the heater 208 increases, but the bubble 920 stops growing at some point because an internal negative pressure also increases together with the increasing volume of the bubble 920. If the application of the voltage is stopped before the bubble reaches its maximum volume, the temperature of the heater 208 decreases, the bubble 920 starts to shrink, and again the liquid comes into contact with the surface of the heater 208, whereby the bubble 920 disappears. At the time of disappearing, cavitation occurs two times: a first cavitation (impact) caused by contact between the shrunk bubble 920 and the heater 208 and a second cavitation in which small bubbles 940 remaining after the first cavitation disappear in a spark.
As a result of the testing by the present inventors, it was confirmed that driving of the heater as described above caused a bubble having a size less than 1.0 μm (a so-called ultrafine bubble, UFB) to be generated in the liquid. It was assumed that gas components dissolved in the liquid resulted are appeared as a large number of UFBs by film boiling in the liquid heated by the heater 208. Furthermore, it was confirmed that bubbles having a size greater than UFBs such as millibubbles and microbubbles had been sufficiently fewer than the UFBs since the manufacture of the UFB-containing liquid, and the number of remaining UFBs after a lapse of three months from the manufacture hardly changed. In other words, using film boiling for bubbles to form, grow, shrink, and disappear allows manufacturing of a UFB-containing liquid having a high purity with a relatively simple configuration and in a short period of time. In addition, if the UFB-containing liquid can be ejected outside by using the growth and shrinkage of bubbles, it is possible to continuously manufacture and collect a UFB-containing liquid having a desired purity.
Only one heater 208 is shown in the figures, but multiple heaters 208 are arranged at predetermined pitches on the heating resistor substrate 200, and one flow path 14 and one ejection opening 11 are prepared for each one of the heaters 208. The plurality of flow paths 14 are connected to a common liquid chamber (not shown) for commonly supplying liquid to the flow paths 14, and the liquid in the common liquid chamber is led to the ejection opening 11 by a capillary force of the flow path 14. The led liquid forms a concave meniscus near the ejection opening 11.
If a voltage is applied and the heater 208 generates heat, film boiling occurs and the bubble 920 is generated (
Then, the bubble 920 shrinks, and cavitation occurs two times as described with reference to
After that, the bubble 920 shrinks, and cavitation occurs two times as described with reference to
It should be noted that
Examples of the liquid that can be used to manufacture a UFB-containing liquid in the present invention include: pure water, ion exchange water, distilled water, bioactive water, magnetic water, lotion, tap water, seawater, river water, clean water and waste water, lake water, groundwater, rainwater, and liquid mixtures thereof. Further, a mixed solvent of water and a water-soluble organic solvent can be used. A water-soluble organic solvent mixed with water for use is not particularly limited, but for example, the following can be specifically used: alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; amides such as N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylformamide, and N,N-dimethyl acetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; cyclic ethers such as tetrahydrofuran and dioxane; glycols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and thiodiglycol; lower alkyl ethers of polyhydric alcohol such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and triethylene glycol monobutyl ether; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; and triols such as glycerol, 1,2,6-hexanetriol, and trimethylolpropane. These water-soluble organic solvents may be used singly or in combination.
[First Embodiment]
The collection container 30 used in the present embodiment is a cylindrical glass container having a diameter of 2 cm and a height of 2 cm and is provided with a helical groove 31 for screwing a cap on its upper part of about 5 mm. Accordingly, after a predetermined amount of the UFB-containing liquid is reserved in the collection container 30, if the collection container 30 is removed from the apparatus 1 and covered with a cap (not shown), it is possible to seal up the inside of the collection container 30 and carry the collection container 30.
To efficiently collect the UFB-containing liquid, it is preferable that a collection port which is an opening of the collection container 30 be wider than the ejection opening surface of the liquid ejecting unit 10 having the ejection openings 11 arranged thereon, and a distance from the ejection opening surface is preferably as short as possible. Also on the internal bottom surface of the collection container 30, a distance from the ejection opening surface is preferably as short as possible. More specifically, it is preferable that a distance between the ejection opening surface and the collection port be 50 mm or less, and a distance between the ejection opening surface and the bottom surface be 100 mm or less. In the present embodiment, the distance between the ejection opening surface and the collection port is set at 5 mm and the distance between the ejection opening surface and the bottom surface is set at 25 mm.
It should be noted that, by way of example, the aspect of covering the collection container 30 by screwing a cap has been described, but the aspect of sealing the collection container 30 is not limited to this. For example, various aspects may be employed, such as an aspect of forcing an elastic cap into the collection port, an aspect of heat-welding the collection port, an aspect of sealing the collection port by using such means as a zip, and the like.
Meanwhile, in the UFB-containing liquid manufacturing apparatus 1, a CPU 311 has control over the apparatus while using a RAM 312 as a work area in accordance with programs stored in a ROM 313. A data transfer I/F (interface) 314 is an interface for transmitting and receiving information to and from the host PC 300. For a connection system between the data transfer I/F 304 on the host PC 300 side and the data transfer I/F 314 on the UFB-containing liquid manufacturing apparatus 1 side, a USB, IEEE1394, LAN, and the like can be used.
A data processing accelerator 316 performs predetermined data processing on data received from the host PC 300 and stored in the RAM 312 under instructions from the CPU 311 and generates ejection data so that the liquid ejecting unit 10 can perform ejection. The data processing accelerator 316 is configured by hardware and can perform high-speed data processing compared to the CPU 311. If the CPU 311 writes parameters required for data processing and data before processing on a predetermined address in the RAM 312, the data processing accelerator 316 is activated to perform the predetermined data processing. It should be noted that the data processing accelerator 316 is not an essential configuration in the present embodiment. The CPU 311 may act as the data processing accelerator 316 instead.
Under instructions from the CPU 311, an ejection controller 315 drives the liquid ejecting unit 10 to eject liquid in accordance with data generated by the data processing accelerator 316 and stored temporarily in the RAM 312. More specifically, once the CPU 311 writes control parameters and ejection data for controlling the liquid ejecting unit 10 on a predetermined address in the RAM 312, the ejection controller 315 is activated, and the liquid ejecting unit 10 is driven and controlled in accordance with the control parameters and ejection data.
Description will be given of operation of manufacturing a UFB-containing liquid by using the UFB-containing liquid manufacturing apparatus 1 of the present embodiment and testing results of a collected UFB-containing liquid. First, in the host PC 300, data for ejecting operation was generated, and the liquid ejecting unit 10 was caused to perform the ejecting operation. More specifically, the tank 20 containing pure water was installed on the liquid ejecting unit 10 and each of the entire 768 nozzles was driven at a driving frequency of 20 KHz. About 5 pl of droplets were ejected from each ejection opening 11 at a frequency of 20 KHz, and after two minutes, the collection container 30 was filled with the UFB-containing liquid. At this time, an ambient temperature was 25° C. and an ambient humidity was 60%.
After the collection container 30 was removed from the UFB-containing liquid manufacturing apparatus 1 and its cap (not shown) was closed to seal the container, the liquid in the collection container 30 was measured by SALD-7500 Fine Bubble Measurement System available from Shimadzu Corporation. It was confirmed that the liquid contained not less than 3.0 billion of ultrafine bubbles (UFBs) having a diameter of less than 1.0 μm per ml.
Bubbles having a size greater than UFBs such as millibubbles and microbubbles rise with buoyancy and collapse when they communicate with atmosphere, and physical impact upon collapsing causes the UFBs to collapse as well. However, in the UFB-containing liquid manufactured according to the present embodiment, bubbles greater than the UFBs have been very few since the manufacture. For this reason, frequency of the physical impact itself is low, and the number of UFBs hardly changes even if the bubbles are left for a long period of time. To verify this, the present inventors stored the UFB-containing liquid, which was manufactured by the liquid ejecting unit 10 and collected and sealed in the glass collection container 30, for three months at a temperature of about 25° C., and the UFB-containing liquid was again measured by the measurement system. As a result, change was hardly seen as for the findings that a content concentration of UFBs was not less than 3.0 billion per ml and that the UFBs accounted for not less than 99.8% of the total bubbles, and the particle size frequency distribution shown in
Next, by using the basic configuration of the UFB-containing liquid manufacturing apparatus 1 of the present embodiment, modifications to more efficiently collect a UFB-containing liquid will be described.
[Modification 1]
It should be noted that in the present modification, liquids contained in the plurality of tanks 20 may not be the same type. Different liquids supplied from their respective tanks 20 may be ejected from individual nozzle arrays 12 and mixed in the same collection container 30, so that a UFB-containing liquid having target properties is generated.
[Modification 2]
In this modification, the ejected droplets can be reliably led to the collection container 30 irrespective of a positional relation between the liquid ejecting unit 10 and the collection container 30. Accordingly, the position and shape of the collection container 30 can be flexibly designed. Furthermore, since droplets containing UFBs are contained in a sealed space cut off from the outside air immediately after being ejected from the liquid ejecting unit 10, it is possible to prevent droplets from evaporating and increase a collection efficiency of the UFB-containing liquid compared to the case of direct ejection toward the collection container 30.
In addition, in the aspect in which the liquid ejecting unit 10 as shown in
Meanwhile,
[Modification 3]
In this configuration, if the liquid ejecting unit 10 is caused to perform ejecting operation with the valve 62A and the valve 62B closed, the liquid in the tank 20 is gradually consumed and the UFB-containing liquid is gradually accumulated in the cap 50. At a timing when the liquid is accumulated in the cap 50 to some extent, the ejecting operation is stopped, and when only the valve 62B is opened and the pump 61 is actuated, the liquid reserved in the cap 50 returns again to the tank 20. The above process is repeated N times, and then the valve 62A is opened with the valve 62B kept closed after (N+1)th ejecting operation is further performed, the liquid in the cap 50 is collected by the collection container 30 according to gravity. In this manner, repeating film boiling and ejecting operation multiple times on the same liquid allows the liquid to have a further increased concentration of UFB content.
The circulation system 60 of
[Modification 4]
Furthermore, in the UFB-containing liquid, to formulate gas included in UFBs and liquid containing UFBs having target properties, it is also possible to apply a predetermined modifier to the liquid in a tank 20.
In need of including a desired gas in UFBs, a modifier may be the desired gas component. More specifically, examples of the modifier include: hydrogen, helium, oxygen, nitrogen, methane, fluorine, neon, carbon dioxide, ozone, argon, chlorine, ethane, propane, air, and gaseous mixtures thereof.
Furthermore, a modifier may be a microbubble-containing liquid including a desired gas component. Microbubbles are bubbles larger than ultrafine bubbles which are intended to be manufactured by the present invention. The microbubbles have a floating speed lower than that of millibubbls and stay in contact with liquid for a long period of time. Accordingly, if microbubbles containing a desired gas are included in liquid beforehand, the gas is encouraged to dissolve in the liquid, and as a result, UFBs containing a desired gas can be generated. More specifically, it is possible to use a microbubble-containing liquid including, for example, hydrogen, helium, oxygen, nitrogen, methane, fluorine, neon, carbon dioxide, ozone, argon, chlorine, ethane, propane, air, and gaseous mixtures thereof.
It should be noted that for the purpose of removing a specific gas component from the UFB-containing liquid after completion, a predetermined gas component or a microbubble-containing liquid including the predetermined gas component may be applied as a modifier. Needless to say, the configuration of applying a diluent as shown in
[Modification 5]
As for droplets ejected from a liquid ejecting unit 10 and a UFB-containing liquid after collected by a collection container 30, a certain level of evaporation cannot be avoided. However, the level of evaporation depends on a surrounding ambient temperature and humidity. Accordingly, in a UFB-containing liquid manufacturing apparatus 1, it is preferable that a temperature and a humidity in an environment in which the liquid ejecting unit 10 and the collection container 30 are placed be appropriately managed. More specifically, it is preferable to maintain a temperature of 70° C. or lower and a humidity of 50° C. or higher.
The first embodiment and its Modifications 1 to 5 have been described, but they may also be combined with each other. For instance, the configurations of Modifications 2 to 4 may also be added to a system having a plurality of tanks 20 and ejection opening arrays 12 as shown in Modification 1. Furthermore, the configurations having the cap 50 as shown in Modification 2 and Modification 3 and the configuration of controlling a temperature and humidity as shown in Modification 5 may be combined, so that a collection efficiency of a UFB-containing liquid is further increased.
Furthermore, as for the first embodiment and Modifications 1 to 3, an aspect of immersing an ejection opening surface of the liquid ejecting unit 10 in liquid may be employed. In the aspect of immersing the ejection opening surface in liquid, evaporation caused by dispersion of droplets can be reduced, and further a collection rate of a UFB-containing liquid can be increased. In this case, the liquid in which the ejection opening surface is immersed may be a UFB-containing liquid ejected from the liquid ejecting unit 10 or may be liquid prepared in advance in a collecting unit.
[Second Embodiment]
The carriage 90 is attached to a guide shaft 100 extending in the X direction and reciprocates in the X direction at a predetermined speed along the guide shaft 100 by a driving force of a carriage motor (not shown). While the carriage 90 moves in the X direction, the liquid ejecting unit 10 ejects liquid in a Z direction, whereby a UFB-containing liquid is gradually reserved in a collection container 30.
At a top end part in the X direction in an area where the carriage 90 is movable, a maintenance unit 110 for performing a maintenance process on the liquid ejecting unit 10 is provided. The maintenance unit 110 is provided with a cap 50, a pump 61, and a valve 62, and can perform a maintenance process on the liquid ejecting unit 10 in a state where the carriage 90 is located immediately above the maintenance unit 110. More specifically, a predetermined amount of liquid can be forcibly discharged from the liquid ejecting unit 10 by causing the cap 50 to abut on the ejection opening surface, opening the valve 62, and driving the pump 61.
In the liquid ejecting unit 10 after performing the ejecting operation to some extent, bubbles larger than UFBs may stagnate inside the liquid ejecting unit 10 and prevent ejection of a UFB-containing liquid. Further, if the temperature of the liquid ejecting unit 10 becomes too high through the ejecting operation, a UFB generation efficiency may decrease or the liquid ejecting unit 10 may not perform suitable ejecting operation. Even in such cases, if the maintenance unit 110 forcibly discharges liquid from the liquid ejecting unit 10, removes bubbles from head, and lowers the temperature of the liquid ejecting unit, the liquid ejecting unit 10 can recover to a normal driving state.
At this time, the liquid forcibly discharged from the liquid ejecting unit 10 by the maintenance unit 110 also includes some UFBs that are not discharged through ejecting operation. Accordingly, a collection container 32 may be newly prepared to contain liquid collected through maintenance operation and the liquid may be used as a UFB-containing liquid. In the two collection containers 30 and 32, an absorber may be placed for retaining liquid in one or two of the collection containers 30 and 32, and the liquids collected by the two collection containers may be led to the same absorber.
It should be noted that although
Further,
The maintenance controller 318 drives the cap 50, the valve 62, and a motor 61 in the case where the carriage 90 is in a position of the maintenance unit 110 to perform a maintenance process on the liquid ejecting unit 10.
It should be noted that a moving speed of the carriage 90, an ejection pattern of the liquid ejecting unit, a frequency of maintenance process by the maintenance unit 110, a suction amount of liquid, and the like are controlled by a host PC 300 sending commands to the UFB-containing liquid manufacturing apparatus 1. Such control may also be made by instructions through a keyboard mouse I/F 304 by a user while checking a state of the UFB-containing liquid manufacturing apparatus 1 via a display on the host PC 300.
Each collection container 30 was made from glass, and the collection port had a diameter of 2 cm. Furthermore, a distance (A-C) between a height A of the ejection opening surface and a height C of the bottom of the collection container was 60 mm for all of the collection containers. Distances (A-B) between the height A of the ejection opening surface and a height B of the collection port were 1 mm, 5 mm, 10 mm, 30 mm, and 50 mm for the collection containers 30 from the left side.
Based on the above, the liquid ejecting unit 10 was driven so as to eject 5 pl of droplets from each ejection opening at a frequency of 20 KHz, and the carriage 90 was reciprocated so that the same ejecting operation was performed in all positions of the collection containers 30. Such ejecting operation was performed for several hours while occasionally transferring the UFB-containing liquid to a different container so that the UFB-containing liquid did not overflow the collection container 30, and then the volumes of the UFB-containing liquid respectively collected by five collection containers 30 were measured.
Meanwhile, the UFB-containing liquid collected individually by the collection containers 30 was measured by SALD-7500 Fine Bubble Measurement System available from Shimadzu Corporation. It was confirmed that all of the collection containers 30 had the same concentration of UFB content. That is, in view of a collection efficiency of the UFB-containing liquid, it is preferable that the collection container 30 be located such that the collection port is as close as possible to the ejection opening surface.
Each collection container 30 was made from glass, and the collection port had a diameter of 2 cm. Furthermore, a distance (A-B) between the height A of the ejection opening surface and the height B of the collection port was 5 mm for all of the collection containers. Distances (A-C) between the height A of the ejection opening surface and the height C of the bottom of the collection container were 30 mm, 60 mm, 70 mm, 80 mm, and 100 mm for the collection containers 30 from the left side. To align the top of the collection ports for the plurality of collection containers 30 having different heights, the present test experiment used a height adjusting tool 41.
Based on the above, the liquid ejecting unit 10 was driven so as to eject 5 pl of droplets from each ejection opening at a frequency of 20 KHz, and the carriage 90 was reciprocated so that the same ejecting operation was performed in all positions of the collection containers 30. Such ejecting operation was performed for several hours while occasionally transferring a UFB-containing liquid to a different container so that the UFB-containing liquid did not overflow the collection container 30, and then the volumes of the UFB-containing liquid respectively collected by five collection containers 30 were measured.
Meanwhile, the UFB-containing liquid collected individually by the collection containers 30 was measured by SALD-7500 Fine Bubble Measurement System available from Shimadzu Corporation. It was confirmed that all of the collection containers 30 had the same concentration of UFB content. That is, in view of a collection efficiency of the UFB-containing liquid, it is preferable that the collection container 30 be located such that its bottom is as close as possible to the ejection opening surface. Furthermore, in consideration of the test experiment shown in
In the present embodiment, the tray 33 having a depth of about 5 mm was used and a distance between the ejection opening surface and the bottom surface of the tray was about 10 mm. By using the tray 33 as a collecting unit in this manner, the distance between the ejection opening surface and the collection port or bottom surface of the collecting unit can be reduced as compared to the case of using the collection container 30, and a collection efficiency of a UFB-containing liquid can be increased. It should be noted that as a material of the tray 33, it is preferable to use an acrylic resin and the like and to subject the receiving surface 33a to water repellent coating treatment with a fluorocarbon resin. By subjecting the receiving surface 33a to water repellent treatment, the UFB-containing liquid adhering to the receiving surface 33 becomes spherical and the UFB-containing liquid can be prevented from evaporating, thereby increasing a collection rate of the UFB-containing liquid.
It should be noted that also in the case of using the sheet 34 as a collecting unit, like the case of using a tray, it is preferable to subject its surface to water repellent treatment. However, in a case where droplets may spill over a peripheral end of a flat sheet to the inside of the apparatus, it is efficient to give absorbency only to the peripheral of the sheet.
Furthermore, in the case of using the sheet 34 as a collecting unit, it is preferable that an area to which droplets are applied should not deviate on the sheet as much as possible. This is because if the ejecting operation is repeatedly performed in the same location of the water repellent sheet 34, a collection rate of a UFB-containing liquid may decrease due to splashing of droplets, and the inside of the apparatus may be contaminated. Therefore, in the present embodiment, the sheet 34 is conveyed in the Y direction every time the liquid ejecting unit 10 performs scanning in the X direction.
In this configuration, main scanning in which the liquid ejecting unit 10 ejects droplets at a predetermined frequency while moving in the X direction and conveying operation in which the conveying roller 130 conveys the sheet 34 in the Y direction by a distance corresponding to a width in which droplets are applied by the main scanning are alternately repeated. If droplet application scanning is completed with respect to substantially the entire area of the sheet 34, the conveying roller 130 discharges the sheet 34 outside the apparatus.
Bending or inclining the water repellent sheet 34 allows freely collecting an applied UFB-containing liquid. For instance, a user may take out the discharged sheet manually to collect a UFB-containing liquid in a collection container that is separately prepared, or a sheet discharging unit of the apparatus may be provided with a mechanism for bending the sheet and collecting a UFB-containing liquid in a desired position. Furthermore, as shown in
In either case, in the case where the water repellent sheet 34 is used as a collecting unit, a distance between the ejection opening surface of the liquid ejecting unit 10 and the flat sheet 34 can particularly be reduced, and it is thus possible to decrease a distance of movement of droplets across a space and to increase a UFB collection efficiency. In this embodiment, by using a PET film having a thickness of 0.5 mm, a distance between the ejection opening surface and the sheet surface could be set at about 1 mm.
Next, by using the UFB-containing liquid manufacturing apparatus 1 as shown in
Meanwhile, in the liquid ejecting unit 10, as a driving frequency of the plurality of heaters 208 increases and the number of times of driving increases, the temperatures of the heater 208 and the liquid around the heater 208 increase. Therefore, in the UFB-containing liquid manufacturing apparatus 1, it is preferable to generate ejection data for driving the liquid ejecting unit 10 so as to maintain the temperature of the liquid ejecting unit 10 within a preferable range.
In a control method 1, a period in which ejecting operation is performed at a maximum driving frequency and a period in which ejecting operation is not performed are alternately repeated. As used herein, the term “maximum driving frequency” means a maximum frequency capable of driving the heater 208 under a condition that the liquid ejecting unit 10 can perform normal ejecting operation. In the figure, periods P1, P3, P5 indicate periods in which ejecting operation is performed at a maximum driving frequency, whereas periods P2, P4, P6 indicate periods in which driving is suspended.
In the periods P1, P3, P5, since a voltage is repeatedly applied to the plurality of heaters 208, the temperature of the liquid ejecting unit 10 increases from T1 to T3. In the periods P2, P4, P6, since application of a voltage to the heaters is suspended, the temperature of the liquid ejecting unit 10 decreases from T3 to T 1. In this manner, in the control method 1, the period in which the liquid ejecting unit 10 is driven and the period in which the driving is suspended are repeated at predetermined intervals, whereby the temperature of the liquid ejecting unit 10 is maintained in a desired range (T1 to T3) and liquid with a greater UFB content can be efficiently manufactured.
In the case of employing the control method 1, the CPU 311 reciprocates the carriage 90 in the X direction in the entire area of the scanning area L0 while causing the liquid ejecting unit to perform ejecting operation only in the collection area L2 where the collection container 30 is placed. Accordingly, a period in which the carriage 90 moves in the collection area L2 corresponds to the periods P1, P3, P5 shown in
Now,
Referring back to
That is, by performing ejecting operation based on binary ejection data as shown in
It should be noted that the temperature of the liquid ejecting unit 10 is affected by a temperature in an environment where the apparatus 1 is installed and the like as well as a driving frequency of the liquid ejecting unit 10. For this reason, there may be a case where temperature variations as shown in
[Third Embodiment]
The water repellent sheet 34 is continuously conveyed in the Y direction at a predetermined speed by a conveying roller 130, and the four liquid ejecting units 10 eject droplets to the sheet 34 at a constant frequency. At this time, ejection data for each liquid ejecting unit 10 is preferably the one shown in
According to the present embodiment, it is possible to manufacture a large quantity of UFB-containing liquid with a high purity in a shorter period of time compared to the second embodiment.
It should be noted that the sheet 34 according to the present embodiment may be a cut sheet or a continuous sheet as long as a UFB-containing liquid applied thereto can be reliably collected. Further, although
[Other Embodiments]
The UFB-containing liquid manufacturing apparatus 1 may be provided with a UFB measurement unit capable of measuring an amount of liquid reserved in a collection container 30 and a content of UFBs in the liquid. A method for measuring a content of UFBs is not particularly limited. For example, it is possible to irradiate the inside of a collection container with a semiconductor laser and make measurement based on a state of scattered light or use a particle tracking analysis method.
For example, in a case where a predetermined amount of UFB-containing liquid is confirmed, the CPU 311 may complete ejecting operation of a liquid ejecting unit 10. Furthermore, in a case where a detected content of UFBs is less than a predetermined value, the circulation system 60 as shown in
In the above description, the aspect of controlling the UFB-containing liquid manufacturing apparatus 1 by the host PC 300 has been described. More specifically, the host PC 300 confirms the condition of the UFB-containing liquid manufacturing apparatus 1, generates data for driving the liquid ejecting unit 10, and performs a maintenance process. However, the present invention is not limited to such an aspect. The UFB-containing liquid manufacturing apparatus 1 itself may have the above-described function of the host PC 300 and a user may operate that UFB-containing liquid manufacturing apparatus 1 via a user interface provided on the UFB-containing liquid manufacturing apparatus 1. Furthermore, the CPU 311 of the UFB-containing liquid manufacturing apparatus 1 may make various controls as described in the above embodiments in accordance with programs stored in a ROM.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2017-167598 filed Aug. 31, 2017, which is hereby incorporated by reference wherein in its entirety.
1 ultrafine bubble-containing liquid manufacturing apparatus
10 liquid ejecting unit
11 ejection opening
14 flow path
30 collection container
208 energy generating element
315 ejection controller
311 CPU
Number | Date | Country | Kind |
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2017-167598 | Aug 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/031029 | 8/22/2018 | WO |
Publishing Document | Publishing Date | Country | Kind |
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WO2019/044631 | 3/7/2019 | WO | A |
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