JP4108725B1 - Recording apparatus and recording method - Google Patents

Abstract

An object of the present invention is to prevent aggregation and sedimentation of solid components contained in a liquid.
A first ink tank and a second ink tank provided in an ink jet recording apparatus according to the present invention are connected to each other by a flow path so that ink can be transferred. An ink jet head 30 is provided between the first ink tank 10 and the second ink tank 20 so as to be able to exchange liquid. Since different pressures are respectively applied to the first and second ink tanks 10 and 20, the ink in the flow path is agitated by the generation of ink flow in the flow path. The first and second pressure regulating pumps 13 and 23 are applied to the first and second ink tanks 10 and 20 so that a constant negative pressure is always applied to the ink inside the inkjet head 30. In order to control the pressure, the ink can be stably ejected even when the ink is being stirred by the ink flow.
[Selection] Figure 1

Description

  The present invention relates to a recording apparatus, and more particularly to a piping structure of an ink supply system that supplies ink from an ink tank to an inkjet head, and pressure control in an ink supply path.

  Inkjet recording apparatuses that use an inkjet head to eject various inks are widely used as consumer printers. In industrial applications, ink jet recording apparatuses are not only large printers for printing dyeing, but also liquid crystal panels that apply color filter films by applying ink containing red, blue, or green dyes to glass substrates. It is also applied to the manufacturing process. Furthermore, the ink jet recording apparatus is being developed as a device manufacturing apparatus for forming a polyimide alignment film by applying ink containing a polyimide precursor.

  When ink is ejected using the ink jet recording apparatus, the ink in the ink tank is supplied to the ink jet head, and the ink is ejected from the ink jet head. In particular, when a liquid crystal panel is manufactured, the ink ejected from the ink jet head includes a color filter pigment, a liquid crystal layer gap holding plastic spacer bead, and the like. When such ink is used in an ink jet recording apparatus, solid components such as pigments and beads dispersed in the ink inside the ink jet head, the ink flow path connecting the ink jet and the ink tank, and the ink tank. May precipitate or settle. As a result, problems such as ink clogging and stability of the ejection characteristics of the inkjet head have occurred in the components of the ink supply system that supplies ink from the ink tank to the inkjet head.

  Inkjet recording apparatuses aimed at solving such problems are disclosed in Patent Documents 1 to 5 below. Hereinafter, the configuration of the inkjet recording apparatus disclosed in Patent Documents 1 to 5 will be described.

  Patent Document 1 discloses a configuration in which a stirring ball is incorporated in an ink cartridge mounted on an ink jet head to prevent precipitation of a pigment contained in the ink. The stirring ball in the ink cartridge moves at a shorter cycle than the precipitation of the solid component contained in the ink in the ink cartridge, so that the ink being printed is stirred to prevent the precipitation of the solid component contained in the ink. It is possible.

  Patent Document 2 discloses a configuration in which ink is circulated in a direction orthogonal to the ink supply direction to the ink jet head. In this configuration, ink is injected in a direction orthogonal to the ink flow of the ink supplied from the ink tank to the inkjet head, and the injected ink is sucked at a position opposite to the ink injection port. Accordingly, an ink flow is generated in a direction orthogonal to the ink flow of the ink supplied from the ink tank to the ink jet head, so that the stagnation of the ink can be prevented and the ink can be stirred.

  Furthermore, Patent Document 3 discloses a configuration in which a pump for circulating ink is provided between two or more communication ports communicating with the ink tank. The pump generates an ink flow for stirring the ink in the vicinity of the bottom having the highest solid component concentration in the ink tank. The ink flow generated by the operation of the pump sucks ink from one of the openings in the ink tank and ejects the ink from the other openings. It becomes possible to do.

  Further, in Patent Document 4, an ink pressurizing pump disposed in an ink flow path is used to forcibly pass from the ink tank to the ink jet head via the ink flow path, and from the ink jet head to the original ink tank via the ink flow path. A configuration of an ink supply system that circulates ink to the head is disclosed. In this configuration, since ink is forcibly circulated in almost all areas where ink is present in the ink jet recording apparatus, a high ink stirring effect can be obtained.

  Further, Patent Document 5 includes a sub ink tank mounted on an ink jet head and a main ink tank disposed at a position independent of the ink jet head, and the sum of ink flow path resistances from the main ink tank to the ink jet head. However, a configuration in which the ink flow path resistance from the sub ink tank to the inkjet head is larger than the sum is disclosed.

  In the ink jet recording apparatus described in Patent Document 5, after the ink in the main ink tank is supplied to the sub ink tank via the ink flow path inside the ink jet head, the ink supplied to the sub ink tank is supplied to the inside of the ink jet head. Back to the main ink tank through the ink flow path. Then, the ink jet head is driven in a state where the ink is flowing back, and the ink is ejected from the ink jet head. When all the ink in the sub ink tank flows out, the ink returned to the main ink tank is pressurized and transferred to the sub ink tank again.

As described above, in the apparatus described in Patent Document 5, as in the apparatus described in Patent Document 4, ink circulation is repeated in all areas where ink exists in the ink jet recording apparatus. It is possible to maintain the concentration appropriately.
Japanese Patent Laid-Open No. 9-309212 (published on December 2, 1997) Japanese Utility Model Publication No. 2-10941 (published on January 24, 1990) JP 2004-351865 A (released on December 16, 2004) JP 2006-116955 A (published May 11, 2006) Japanese Patent Laid-Open No. 10-114081 (published May 6, 1998)

  However, the conventional configurations described in Patent Documents 1 to 5 have the following problems. Hereinafter, problems in the configuration of the ink jet recording apparatus disclosed in Patent Documents 1 to 5 will be described.

  The configuration described in Patent Document 1 is effective for stirring the ink in the ink cartridge. For example, when spacer bead ink that settles in a relatively short time is used, the ink from the ink cartridge to the inkjet head is used. The beads settle in the flow path. As a result, problems such as the opening / closing failure of the electromagnetic valve disposed in the ink flow path, clogging with an injection needle or the like connecting the ink cartridge and the piping, and the like become problems particularly when the apparatus is operated for a long time.

  Also, since the ink inside the inkjet head is not agitated, when spacer bead ink is used, the number of beads contained in a single drop of ejected ink varies, and the settled beads move to the vicinity of the nozzle and contain a large amount of beads. May be discharged. As a result, the reproducibility of the ink landing position becomes unstable. Furthermore, when the apparatus is operated for a long period of time, beads settle in the ink flow path or the ink jet head, so that the bead dispersion concentration in the ink is lowered and the number of beads to be applied is reduced.

  Furthermore, the configuration described in Patent Document 2 does not consider the pressure state of the ink inside the inkjet head. In order to stably eject ink from the inkjet head, it is necessary to maintain the ink pressure inside the inkjet head at a negative pressure. When the ink pressure inside the inkjet head is negative, the liquid meniscus at the tip of the nozzle placed on the head is pulled inside the nozzle. This is because the liquid prevents the liquid from overflowing abnormally outside the nozzle.

  However, in the configuration described in Patent Document 2, since the ink is circulated using a pressure pump, the ink pressure inside the inkjet head is kept at a positive pressure. For this reason, the ink jet head cannot be driven during ink circulation, and ink cannot be ejected. As a result, the circulation of the ink must be stopped when the ink is ejected. For example, when ink jet recording is performed so that the ejection of a small amount of ink is repeated intermittently, the ink stirring effect is reduced, The concentration cannot be kept uniform.

  Further, in the configuration described in Patent Document 3, a stirring effect is obtained for the ink in the ink tank, as in the configuration described in Patent Document 1, but in the ink flow path from the ink tank to the inkjet head, Solid components in the ink will settle. For this reason, when using an ink in which the solid component in the ink settles in a relatively short time, such as spacer bead ink, the ink concentration to be ejected cannot be kept constant, and the ink ejection There is a problem in reproducibility of characteristics.

  Furthermore, in the configuration described in Patent Document 4, when the ink is forcibly circulated, the ink pressure in the ink jet head is not properly controlled, so that ink ejection from the ink jet head is substantially impossible. That is, the ink circulation is stopped while the ink jet head is being driven, and the ink is forcibly circulated while the ink jet head is at rest.

  When an ink jet recording apparatus is used as a device manufacturing apparatus, the device manufacturing apparatus is normally operated continuously, and the ink jet head is continuously driven, so that the ink circulation is shortened. In particular, when an ink having a relatively high sedimentation speed, such as bead ink, is used, the effect of stirring becomes poor. There is a problem of becoming unstable.

  Further, in order to improve the stirring effect of the ink in the ink flow path including the ink jet head, when the pressurization pressure of the circulation pump is increased, the ink meniscus formed by the nozzle of the ink jet head cannot withstand the positive pressure, Ink overflows from the nozzles. As a result, a cleaning operation of the inkjet head such as wiping is required, and there is a problem that device production tact increases and device productivity decreases.

  Further, the configuration described in Patent Document 5 is characterized in that the ink flow path resistance from the ink jet head to the main ink tank is larger than the ink flow path resistance from the sub ink tank to the ink jet head. . For this reason, the ink backflow from the sub ink tank to the main ink tank can be continued as slowly as possible for a long time. Therefore, when ink containing plastic beads that settle in a relatively short time is used, stirring is performed. The effect and anti-settling effect are poor. Further, similarly to the configuration described in Patent Document 4, there are problems that clogging in the ink flow path and ink ejection characteristics become unstable.

  Further, when the ink returned to the main ink tank is pressure-fed again to the sub ink tank, it is configured to prevent the ink meniscus from being broken (ink overflow) formed in the nozzle of the inkjet head. The internal ink pressure does not take into account the stability of ink ejection.

  In the configuration described in Patent Document 5, when no pressure is applied to the main ink tank, a negative pressure is applied to the inkjet head, and when the main ink tank is pressurized, a positive pressure is applied to the inkjet head. Is done. That is, when the ink is pushed up from the main ink tank to the sub ink tank, the air vent valve is adjusted to prevent the pressure in the sub ink tank from continuing to rise, so the pressure in the sub ink tank is positive. At this time, a positive pressure that does not cause the ink meniscus of the head to fail is applied to the main ink tank.

  As a result, when ink flows from the sub ink tank to the main ink tank, a negative pressure is applied inside the head, but when ink flows from the main ink tank to the sub ink tank, a positive pressure is applied inside the head. It becomes difficult to drive the head stably. In addition, after the ink flows from the sub ink tank to the main ink tank, when the ink flow is reversed from the main ink tank to the sub ink tank, the ink jet head must be temporarily stopped and the apparatus is continuously operated. I can't.

  For this reason, when the ink is substantially pumped from the main ink tank to the sub ink tank, the ink cannot be ejected, and the device production inkjet recording apparatus that performs continuous operation periodically pauses the apparatus. It is necessary to transfer ink between two ink tanks. As a result, there is a problem that the device production tact cannot be improved.

  Furthermore, the sub ink tank has a configuration in which the ink inside is in contact with air, and air bubbles dissolved in the ink are generated by cavitation caused by vibration in the kHz order that occurs when the inkjet head is driven. In the inkjet technology for device manufacturing, for example, in order to improve productivity by driving the inkjet head at a relatively high frequency, such as 10 kHz to 100 kHz, a certain level of ink ejection stability is required even during high frequency driving, It is required to prevent cavitation. In industrial (device manufacturing) ink, degassed ink from which dissolved air has been removed is used. However, in the configuration of the ink supply system described in Patent Document 5, it is impossible to use degassed ink. When mounted on a recording apparatus, the drive frequency of the ink jet head cannot be increased, and there is a problem in device productivity.

  The present invention has been made in view of the above problems, and its purpose is to aggregate solid components even when ink containing solid components such as pigments, plastic particles, and metal particles is used for a long period of time. An object of the present invention is to provide a piping structure of an ink supply system for an ink jet head capable of preventing precipitation and sedimentation, and an ink jet recording apparatus.

  In order to solve the above problems, a recording apparatus according to the present invention includes a first liquid tank to which a first pressure is applied and a second liquid to which a second pressure different from the first pressure is applied. A flow path connecting the liquid between the first liquid tank and the second liquid tank so that the liquid can be transferred; and a flow path between the first liquid tank and the second liquid tank. In addition, the liquid is reciprocated between the first and second liquid tanks via the flow path and the head connected so as to be able to exchange liquid, and a constant negative pressure is always applied to the liquid inside the head. As described above, it is characterized by comprising pressure control means for controlling the pressure applied to the first and second liquid tanks.

  In order to solve the above problems, a recording method according to the present invention includes a first liquid tank to which a first pressure is applied and a second liquid to which a second pressure different from the first pressure is applied. The liquid is reciprocated in a flow path connecting between the first and second liquid tanks with respect to the head connected to the tank so as to be able to exchange liquid, and between the first and second liquid tanks. A pressure control step of controlling the pressure so as to apply a pressure to the first and second liquid tanks so that a constant negative pressure is always applied to the liquid inside the head connected to be able to exchange liquid. It is characterized by including.

  According to the above configuration, since different pressures (water head difference levels) are applied to the first liquid tank and the second liquid tank, liquid pressure differences (water head differences) generated between the plurality of liquid tanks. The flow path between the liquid tanks is changed from a liquid tank to which a higher pressure is applied (a liquid tank having a higher water head difference) to a liquid tank to which a lower pressure is applied (a liquid tank having a lower water head difference). Liquid flows through.

  At this time, since the head is connected to the flow path between the first liquid tank and the second liquid tank, a liquid flow is generated in all regions where the liquid in the recording apparatus including the inside of the head can exist. Can be made. As a result, even if the liquid to be used is a liquid containing a solid component, it is possible to prevent aggregation and precipitation of the solid component.

  Further, the pressure applied to the first and second liquid tanks is such that the liquid is reciprocated between the first and second liquid tanks and a constant negative pressure is always applied to the liquid inside the head. Are provided so that the liquid can be stably ejected in a state where a liquid flow is generated in the recording apparatus due to the pressure difference between the first pressure and the second pressure. it can.

  That is, since the ink pressure inside the head is always a negative pressure, the liquid meniscus at the tip of the nozzle disposed in the head is pulled inside the nozzle. This prevents the liquid from overflowing abnormally to the outside of the nozzle due to residual vibration of the meniscus at the time of liquid discharge or after discharge. As a result, stable liquid discharge becomes possible, and device production yield can be improved in device manufacturing using the recording apparatus.

  As described above, in the conventional recording apparatus, it was not possible to accurately perform the liquid agitation and the liquid ejection at the same time. According to the recording apparatus of the present invention, the liquid discharge characteristics such as the liquid discharge speed and the discharge amount can be stabilized even while the liquid is generated and the liquid is stirred. Agitation and liquid discharge can be simultaneously performed with high accuracy. As a result, device production yield can be improved in the device manufacturing process.

  In the recording apparatus according to the present invention, the pressure control means may be configured so that all of the liquid in one liquid tank of the first and second liquid tanks is liquid before being transferred into the other liquid tank. It is preferable to control the pressure applied to the first and second liquid tanks so as to reverse the transfer direction.

  According to the above configuration, the pressure in each liquid tank is changed before the liquid in the liquid tank to which the higher pressure is applied is completely transferred to the liquid tank to which the lower pressure is applied. For example, the pressure applied to the plurality of liquid tanks is changed so that the lower pressure is applied to the liquid tank to which the high pressure is applied while the higher pressure is applied to the liquid tank to which the low pressure is applied. . As a result, since the liquid flow can efficiently generate a liquid flow in all areas where the liquid is present in the recording apparatus, even if the liquid contains a solid component, aggregation and precipitation of the solid component are prevented. be able to.

  For example, when the liquid tank is a widely spouted bag with spouts, pressurization and depressurization of the bag are performed by pressurizing and depressurizing the outside environment of the bag. At this time, if a certain amount of liquid exists in the bag, it reacts to the outside environment and the liquid in the bag is pressurized and depressurized by expansion and contraction of the bag. On the other hand, when the amount of liquid in the bag is extremely small, the bag does not expand and contract due to the rigidity of the bag, and the pressure cannot be accurately controlled.

  Therefore, as described above, the pressure in each liquid tank can be accurately controlled by changing the pressure in each liquid tank before the liquid in one liquid tank is completely transferred to the other liquid tank. Since the liquid flow can always be generated in all the liquid supply channels in the recording apparatus, the liquid can be effectively stirred.

  In the recording apparatus according to the present invention, the pressure control means may include the first and second liquid tanks before all of the liquid in one liquid tank is transferred into the other liquid tank. The pressure applied to the first liquid tank is changed from the first pressure to the second pressure, and the pressure applied to the second liquid tank is changed from the second pressure to the first pressure. It is preferable to change the pressure.

  According to the above configuration, the pressure control means applies the first pressure to the first liquid tank and applies the second pressure to the second liquid tank, and the first pressure and the second pressure are applied. The liquid is transferred from one of the first and second liquid tanks to the other by the pressure difference between the first and second liquid tanks. Then, the pressure control means applies the second pressure to the first liquid tank before the liquid in the first or second liquid tank is completely transferred to the other, and applies the second pressure to the second liquid tank. The pressure is controlled so that a pressure of 1 is applied. By repeating such pressure control, the liquid is reciprocated between the first and second liquid tanks.

  Therefore, since the liquid flow can efficiently generate the liquid flow in all areas where the liquid exists in the recording apparatus, it is possible to prevent the aggregation and precipitation of the solid component even in the case of the liquid containing the solid component. Can do. In addition, since the pressure applied between the plurality of liquid tanks is switched, a reciprocating liquid flow having a substantially constant speed can be generated between the liquid tanks, so that the liquid can be stirred more uniformly. .

  In the recording apparatus according to the present invention, the first resistor in the flow path between the first liquid tank and the head, and the flow path between the second liquid tank and the head. It is preferable that the second resistance is substantially the same.

  According to the above configuration, the flow path resistance between the flow path between the first liquid tank and the head and the flow path between the second liquid tank and the head are substantially the same. The flow rate and flow rate of the liquid flow from the liquid tank toward the second liquid tank and the liquid flow from the second liquid tank toward the first liquid tank can be controlled in substantially the same manner. For example, if the channel structures are substantially the same, there is an effect that it is not necessary to obtain the resistance value in the channel.

  Specifically, the flow path resistance can be reduced by making the flow path structures from the first and second liquid tanks to the head (three-dimensional structures such as flow path length, flow path cross-sectional area and bent shape) substantially the same. By making them substantially the same, the pressure applied to the head becomes an intermediate value between the pressures applied to the first and second liquid tanks without obtaining the channel resistance value of the actual liquid supply channel. . As a result, the pressure in the head can be easily set, and the pressure control in the recording apparatus can be easily performed, so that the maintenance and manageability of the recording apparatus is improved.

  In the recording apparatus according to the present invention, the pressure control means may be configured such that the first pressure is P1, the second pressure is P2, the pressure applied to the liquid in the head is P, and P1> P> P2. When the relationship is satisfied, a first resistance R1 in the flow path between the first liquid tank and the head, and a second resistance in the flow path between the second liquid tank and the head. The resistance R2 of the above satisfies (P1−P) / R1 = (P−P2) / R2 and before all of the liquid in the first liquid tank is transferred into the second liquid tank, When the third pressure P3 is applied to the first liquid tank, the fourth pressure P4 is applied to the second liquid tank, and the relationship P4> P> P3 is satisfied, the first resistance R1 and The second resistor R2 is such that (P−P3) / R1 = (P4−P) / R2 is satisfied. Body tank, and it is preferable to control the pressure applied to the liquid in the head.

  According to said structure, when a liquid is transferred from a 1st liquid tank to a 2nd liquid tank, the liquid flow characteristic (liquid flow rate, liquid flow velocity, etc.) produced between a 1st liquid tank and a head, The liquid flow characteristics generated between the second liquid tank and the head are substantially the same. Further, when the pressure applied to the first liquid tank and the second liquid tank changes and the liquid is transferred from the second liquid tank to the first liquid tank, the second liquid tank and the head The liquid flow characteristic generated between the two and the liquid flow characteristic generated between the first liquid tank and the head are substantially the same.

  As a result, in the flow path connecting the first liquid tank and the second liquid tank, the shape of the first flow path between the first liquid tank and the head and the second liquid due to various restrictions. Even when the shape of the second flow path between the tank and the head is different and the flow resistances of the first flow path and the second flow path are different, the liquid is uniformly stirred by the liquid flow. Is possible. At the same time, since a constant pressure can be applied to the liquid in the head, the liquid ejection characteristics from the head can be stabilized.

  In the recording apparatus according to the present invention, it is preferable that the pressure control unit holds the pressure applied to the liquid in the head when the liquid is discharged within a range of ± 0.5 kPa with respect to the set pressure. .

  According to the above configuration, the pressure control means adjusts the liquid pressure in the head within a range of ± 0.5 kPa with respect to the set pressure while stirring the liquid by the liquid flow in the liquid flow path including the inside of the head. Because of the control, it is possible to ensure the liquid discharge stability within the range of about ± 2% of the liquid discharge speed and about ± 3% of the liquid discharge volume without changing the head driving conditions as appropriate. It is. As a result, the device production yield can be improved in the device manufacturing process using the recording apparatus.

  In the recording apparatus according to the present invention, the pressure control means may be configured such that the liquid flow rate per unit time of the liquid transferred through the flow path is a liquid per unit time of the liquid that flows out of the apparatus due to ejection from the head. It is preferable to control the pressure applied to the liquid tank and the head so as to be twice or more the outflow amount.

  According to the above configuration, sufficient liquid flow is ensured even when the liquid to be circulated in order to generate liquid flow in the liquid supply flow path by discharging the liquid by driving the head. Can do. For this reason, precipitation and sedimentation of the solid component contained in the liquid can be prevented more reliably.

  In the recording apparatus according to the present invention, it is preferable that the liquid in the liquid tank, the flow path, and the head do not come into contact with air except for the liquid discharge port formed in the head.

  According to the above configuration, the recording apparatus is configured such that the liquid in the liquid tank, the flow path, and the head, that is, the liquid in the recording apparatus does not come into contact with air except at the liquid discharge port formed in the head. Has been.

  Therefore, since the discharged liquid can be stirred in a state where air is blocked, in addition to preventing precipitation and settling of the liquid solid component, high-frequency driving stability can be realized at the same time. As a result, even when this recording apparatus is applied to device manufacture, device productivity can be further improved.

  In the recording apparatus according to the present invention, the flow path includes a first flow path between the first liquid tank and the head, and a second flow path between the second liquid tank and the head. It is preferable that the apparatus further includes a third flow path that includes a path and connects the first liquid tank and the second liquid tank so that the liquid can be transferred without using the head.

  According to said structure, the 1st liquid tank and the 2nd liquid tank are connected, The 3rd flow path which does not pass a head is further comprised. Then, a liquid flow is generated between the first liquid tank and the second liquid tank without passing through the head. As a result, the liquid in the liquid tank can be agitated without affecting the liquid discharge from the head. For example, a large amount of liquid is stored in the liquid tank, Even when the liquid remains in the liquid, it is possible to effectively prevent aggregation and precipitation of solid components contained in the liquid.

  In the recording apparatus according to the present invention, it is preferable that the first, second, and third flow paths each have a valve.

  According to said structure, the liquid flow which generate | occur | produces in each flow path is controllable by opening and closing suitably the valve which each 1st, 2nd and 3rd flow path has. That is, for example, by closing the valves in the first flow path and the second flow path and opening only the valves in the third flow path, the first liquid tank and the second liquid are not passed through the head. A liquid flow is generated between the tank and the tank. Thereby, a liquid can be reciprocated more smoothly between liquid tanks. At this time, since the generation of the liquid flow does not affect the driving state of the head, it is possible to arbitrarily set the liquid stirring time, the number of times of liquid reciprocating transfer, and the like. Accordingly, a liquid having a constant concentration can be used by setting the number of times of reciprocal transfer of liquid even if it is a liquid containing particles having a relatively high sedimentation speed. As a result, it is possible to widen the characteristic range relating to sedimentation or precipitation of the liquid that can be used by the recording apparatus.

  In the recording apparatus according to the present invention, the flow path resistance R3 of the third flow path is greater than the sum (R1 + R2) of the flow path resistance R1 of the first flow path and the flow path resistance R2 of the second flow path. Small is preferable.

  According to the above configuration, the flow path resistance of the third flow path is the sum of the flow path resistance of the first flow path and the flow path resistance of the second flow path, that is, the flow path of the flow path passing through the head. Since it is smaller than the resistance, it is possible to generate a liquid flow having a higher flow velocity in the third flow path. As a result, it is possible to stir the liquid more effectively without affecting the driving state of the head. However, a stable liquid can be used. As a result, it is possible to widen the characteristic range related to sedimentation or precipitation of the liquid that can be used by the recording apparatus.

  In the recording apparatus according to the present invention, the liquid is applied to the first liquid tank when the liquid is transferred between the first liquid tank and the second liquid tank via the third flow path. The difference between the first pressure and the second pressure applied to the second liquid tank is the difference between the first liquid tank and the second liquid tank via the first and second flow paths. It is preferable that the difference between the first pressure applied to the first liquid tank and the second pressure applied to the second liquid tank when transferring the liquid between the first and second liquid tanks is larger.

  According to the above configuration, the pressure difference between the first and second liquid tanks when the liquid flow is generated in the third flow path is the flow path (first and second flow paths) that passes through the head. Since the pressure difference between the first and second liquid tanks when the liquid flow is generated is larger than the first flow rate, a liquid flow with a higher flow velocity can be generated in the third flow path. As a result, it is possible to stir the liquid more effectively without affecting the driving state of the head, and even if the liquid contains particles having a relatively high sedimentation speed, The concentration of can be stabilized. As a result, it is possible to widen the characteristic range related to sedimentation or precipitation of the liquid that can be used by the recording apparatus.

  In the recording apparatus according to the present invention, the first and second negative pressures are always applied to the liquid in the head connected to the flow path connecting the first and second liquid tanks. Since the pressure applied to each liquid tank is controlled, the liquid can be stably discharged from the head while efficiently stirring the liquid between the plurality of liquid tanks. As a result, it is possible to continuously discharge a liquid using a liquid having a constant concentration.

(First embodiment)
A first embodiment according to the present invention will be described below with reference to FIG. FIG. 1 is a schematic cross-sectional view in the direction orthogonal to the ink supply flow path of the ink jet recording apparatus and the ink chamber row of the ink jet head according to the present invention. As shown in FIG. 1, the ink jet recording apparatus (recording apparatus) has two ink tanks, a first ink tank (first liquid tank) 10 and a second ink tank (second liquid tank) 20. is doing.

  The first ink tank 10 includes a first ink bag 11 that is hermetically sealed in a first pressure box 12. The first pressure box 12 includes a first pressure adjusting pump (pressure control means) 13 that can be pressurized and depressurized, and a first pressure gauge 14 that measures the pressure in the first pressure box 12. Is connected.

  Similarly, the second ink tank 20 includes a second ink bag 21 that is hermetically sealed in a second pressure box 22. The second pressure box 22 has a second pressure adjusting pump (pressure control means) 23 capable of pressurization and pressure reduction, and a second pressure gauge 24 for measuring the pressure in the second pressure box. It is connected.

  Further, when the first pressure adjusting pump 13 and the second pressure adjusting pump 23 apply the set pressure to the first pressure box 12 and the second pressure box 22, respectively, and further change the set pressure value, A new set pressure is applied to the first pressure box 12 and the second pressure box 22. The pressure adjustment pumps 13 and 23 may be feedback-controlled while the pressure gauges 14 and 24 monitor the pressure values of the pressure boxes 12 and 22.

  Further, the first ink bag 11 is connected to a first ink supply flow path (first flow path) 15, and the second ink bag 21 is connected to a second ink supply flow path (second flow path). ) 25. The first ink supply channel 15 and the second ink supply channel 25 are individually connected to ink supply channel connection portions 31 and 32 of the inkjet head (head) 30, respectively.

  The ink jet head 30 has two common ink chambers 33 and 34, and the two common ink chambers 33 and 34 communicate with each other via an ink chamber 35 for transferring ink. The ink jet head 30 further includes a nozzle plate 37 in which a nozzle hole 36 is formed. The nozzle plate 37 is bonded to the ink jet head 30 so that the nozzle hole 36 is disposed at the center of the ink chamber 35. Yes.

  As shown in FIG. 1, the height position of the nozzle hole 36 of the inkjet head 30 is equal to the height position where the first ink bag 11 and the second ink bag 21 are placed horizontally. When no pressure is applied to the ink pressure boxes 12 and 22, the pressure applied to the ink meniscus formed in the nozzle hole 36 when the ink is filled in the inkjet head 30 is the first and second ink bags. The water head difference is almost equal to the ink inside, and is almost equal to the atmospheric pressure.

  Therefore, in a state where no pressure is applied to the pressure boxes 12 and 22, the ink meniscus formed in the nozzle hole 36 does not overflow from the nozzle hole 36 due to the water repellent film formed on the surface of the nozzle plate 37. No air is sucked into the nozzle hole 36. In the present embodiment, the three-dimensional shape of the ink flow path connecting from the first ink tank 10 to the second ink tank 20 via the inkjet head 30 is symmetrical about the position of the nozzle hole 36. Designed to. For this reason, the flow path resistance from the position of the nozzle hole 36 to the first ink tank is approximately equal to the flow path resistance from the position of the nozzle hole 36 to the second ink tank.

  Next, a method for generating an ink flow in the ink supply flow path including the inside of the ink jet head in the ink jet recording apparatus configured as described above will be described. As an initial state of ink filling, the ink bag 11 of the first ink tank 10 is pre-filled with about 110 cc of ink with respect to an ink capacity of 120 cc, and the ink bag 21 of the second ink tank is filled with 120 cc. About 10 cc of ink is filled with respect to the ink capacity. The description will be made in the state in which ink is filled in the ink jet head 30 and the ink supply channels 15 and 25.

  Then, the pressure adjustment pump 13 connected to the first ink tank 10 and the pressure adjustment pump 23 connected to the second ink tank 20 are operated simultaneously, and the first pressure gauge 14 and the second pressure gauge are operated. The pressure adjustment pumps 13 and 23 are controlled while monitoring the pressure value of 24 to apply a pressure of +1.0 kPa to the external ink pressure (usually atmospheric pressure) to the first ink tank, and the second ink A pressure of -3.0 kPa is applied to the tank with respect to the external environment pressure.

  The first and second ink tanks 10 and 20 communicate with each other via the ink supply channels 15 and 25 and the ink chambers 33, 34, and 35 inside the inkjet head 30. For this reason, ink flows out from the ink bag 11 of the first ink tank 10 on the higher pressure side, and passes through the ink supply channel 15, the common ink chamber 33, the ink chamber 35, the common ink chamber 34, and the ink supply channel 25. The ink flows into the ink bag 21 of the second ink tank 20 on the lower pressure side via the sequential passage.

  At this time, at the position of the nozzle hole 36 of the ink jet head 30, an ink flow is generated in the ink chamber 35 inside the ink jet head of the nozzle hole 36 in the arrow direction from the left to the right shown in FIG. The ink flow paths such as the ink chambers in the ink jet head 30 including the vicinity of the ink and the ink in the ink supply flow paths 15 and 25 are inks containing solid components due to the stirring effect of the ink flow. And settling can be prevented.

  Further, as the ink bags 11 and 21, for example, a bag in which the periphery of a film obtained by laminating aluminum foil with two polyethylene terephthalate films is used, and a spout made of polypropylene is sandwiched in a part of the heat-welded portion of the bag. Good. Then, the spout portion may be connected to a flow path by being inserted into an injection needle attached to each ink bag side end of the ink supply flow paths 15 and 25.

  Further, since most of the ink flow paths use SUS pipes, air may permeate and mix into the ink bags 11 and 21 and the ink supply flow paths 15 and 25 through the ink flow path piping and the ink bag. Absent. Also, since ink is not agitated in an ink tank or an ink bottle having a structure in which air and ink come into contact with each other, the ink jet recording apparatus of the present invention is stable when using deaerated ink from which air dissolved in ink is removed. The deaerated state can be maintained. Accordingly, it is possible to prevent the generation of bubbles due to cavitation in the ink chamber 35 that occurs when the ink jet head 30 is driven, so that more stable ink ejection can be realized from the ink jet head 30.

  Further, although it varies depending on the ink supply channels 15 and 25 and the internal structure of the inkjet head 30, an ink flow of 1.0 cc / min is generated in this embodiment. Since the ink bag 11 is filled with 110 cc of ink, the ink will flow out of the ink bag 11 in about 110 minutes. Here, when the inside of the ink bag is set to a low pressure due to the influence of the rigidity of the ink bag, the pressure applied to the ink in the ink bag increases as the ink amount in the ink bag approaches the full amount. On the other hand, when the inside of the ink bag is set at a high pressure, the pressure applied to the ink in the ink bag decreases as the remaining amount of ink in the ink bag decreases. For this reason, it is possible to allow ink to flow into the ink bags 11 and 21 up to the ink bag capacity of 120 cc. The ink needs to be filled within a range of the degree.

  In the present embodiment, when the amount of ink discharged from the inkjet head 30 is not taken into consideration, when the ink in the first ink bag 11 flows from 110 cc in the initial state to the remaining amount of 10 cc, or the second ink bag When 110 cc of ink flows into 21, the pressures of the first and second ink tanks 10 and 20 are switched. That is, about 100 minutes after the ink starts to flow out from the first ink tank 10, the pressure applied to the first ink tank 10 is changed from +1.0 kPa to −3.0 kPa, and the second ink tank 20. The pressure applied to is changed from -3.0 kPa to +1.0 kPa.

  After the pressure is switched in this way, the ink flows back from the second ink tank 20 on the higher pressure side to the first ink tank 10 on the lower pressure side. When the ink discharge amount from the inkjet head 30 is not taken into consideration, the pressure applied to the ink tank is similarly switched about 100 minutes after the ink starts to flow out from the second ink tank 20. By repeatedly performing such pressure switching, the ink is reciprocated between the first ink tank 10 and the second ink tank 20, so that an ink flow is always generated in the ink jet recording apparatus. it can.

  Further, the flow path resistance between the position of the nozzle 36 and the first ink tank 10 and the flow path resistance between the position of the nozzle 36 and the second ink tank 20 are configured to be equal. The pressure loss due to the ink being transferred in the flow path is also equal between the forward path and the return path of the ink that is reciprocated. Therefore, the differential pressure between the external environment pressure (usually atmospheric pressure) at the position of the nozzle 36 and the pressure applied to the ink is an intermediate value between the pressure of the first ink tank 10 and the pressure of the second ink tank − It is always constant at a negative pressure of 1.0 kPa. Therefore, since the ink jet head 30 can always eject ink in a state where a constant negative pressure is applied, ink overflow from the nozzle can be prevented and more stable ink ejection can be realized.

  In the present embodiment, first, a pressure of +1.0 kPa is applied to the first ink tank 10, and a pressure of −3.0 kPa is applied to the second ink tank 20. The pressure is controlled so that a negative pressure of −1.0 kPa is constantly applied to the. A positive pressure and a negative pressure can be applied to the first and second ink tanks 10 and 20, respectively, but since a constant negative pressure is always applied to the ink inside the inkjet head 30, When a positive pressure is applied to one ink tank, it is necessary to apply a relatively large negative pressure to the other ink tank. In addition, if different negative pressures are applied to the first and second ink tanks 10 and 20, an ink flow can be generated in the ink jet head 30 by the pressure difference, and the ink jet head. A constant negative pressure can always be applied to the ink inside 30.

  Further, the pressures of the first ink tank 10 and the second ink tank 20 can be accurately set by feedback control of the pressure adjusting pumps 13 and 23 based on the pressure values measured by the pressure gauges 14 and 24. Can do. For this reason, the error range of the pressure applied to the ink tank can be suppressed to ± 0.5 kPa or less, and control can be performed with high accuracy. Then, the discharge speed from the inkjet head 30 can be suppressed to a fluctuation range of, for example, 10 m / s ± 0.2 m / s or less, and the ink discharge droplet amount can be suppressed to, for example, a fluctuation range of 10 pl ± 0.3 pl or less. Ink can be ejected stably.

  For this reason, when the ink jet recording apparatus of the present invention is used as a device manufacturing apparatus, the fluctuation range of ± 3% or less of the accuracy of the ejected ink droplet landing position due to the speed variation and the film thickness accuracy of the device functional film due to the variation of the ink droplet amount Therefore, sufficient reliability and device production yield can be realized.

  Further, when the pressures of the first ink tank 10 and the second ink tank 20 are switched, the negative pressure (in this embodiment) is applied to the ink in the inkjet head 30 as an intermediate value of the pressure applied to each ink tank. In this case, the ink pressure of the inkjet head 30 can be kept at a constant negative pressure even when the pressure is switched by gradually changing the pressure while maintaining the state where the voltage is applied. For this reason, even if the device production apparatus operates continuously, it is not necessary to stop the apparatus operation (ink ejection) for pressure switching, and the apparatus operation and the control of the ink supply system of the inkjet head 30 are synchronized. There is no need to control. As a result, the manageability of the ink jet recording apparatus can be improved.

  At one point of pressure switching, the pressure applied to the first ink tank 10 is the same as the pressure applied to the second ink tank 20, and the pressure applied to the ink in the inkjet head 30 is also the same. When this happens, the ink flow in the inkjet recording apparatus is completely stopped. However, since the stop of the ink flow is a very short time at one point of pressure switching, even if the ink contains large particle size plastic beads having a relatively high sedimentation speed, there is a large variation in the ink density. Does not occur and does not cause major problems.

(Second Embodiment)
A second embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a schematic sectional view showing a second embodiment of the ink jet recording apparatus of the present invention. As shown in FIG. 2, the ink jet recording apparatus according to the present embodiment includes a first ink tank 10 and a second ink tank 20 as in the first embodiment, and further includes a third ink tank 10 ′. And a fourth ink tank 20 '.

  The third ink tank 10 ′ is provided on the first ink tank 10 side with the inkjet head 30 as the center, and the fourth ink tank 20 ′ is the second ink tank 20 ′ with the inkjet head 30 as the center. On the side. Similar to the first ink tank 10 and the second ink tank 20, the third ink tank 10 ′ and the fourth ink tank 20 ′ include a pressure box, an ink bag, a pressure adjustment pump, and a pressure gauge. Yes.

  The ink bag of the third ink tank 10 ′ is connected to the third flow path 18, and the third flow path 18 merges with the first flow path 15 in the first flow path piping 19. Similarly, the ink bag of the fourth ink tank 20 ′ is connected to the fourth flow path 28, and the fourth flow path 28 merges with the second flow path 25 in the second flow path piping 29. Yes. The first channel pipe 19 is connected to the inkjet head 30 via the ink supply channel 31, and the second channel piping 29 is connected to the inkjet head 30 via the ink supply channel 32. Thus, the first to fourth ink tanks are connected to each other via the inkjet head 30 so that ink can be transferred to each other.

  Further, the first flow path 15 includes a first two-way valve (valve) 16, and the second flow path 25 includes a second two-way valve 26. Similarly, the third flow path 18 includes a third two-way valve 17, and the fourth flow path 28 includes a fourth two-way valve 27. Accordingly, it is possible to control which ink tank generates the ink flow by opening and closing the two-way valve included in each flow path. For example, when an ink flow is generated using the first ink tank 10 and the second ink tank 20, the first two-way valve 16 and the second two-way valve 26 are open, The three two-way valve 17 and the fourth two-way valve 27 are closed. Before all the ink in the first ink tank 10 is transferred to the second ink tank 20, the first two-way valve 16 and the second two-way valve 26 are closed, and the third two-way valve. By simultaneously opening 17 and the fourth two-way valve 27, an ink flow is generated between the third ink tank 10 'and the fourth ink tank 20'. Accordingly, since the ink flow can be continuously generated without stopping, precipitation and settling of the solid component contained in the ink can be prevented more reliably.

  The ink jet recording apparatus according to the second embodiment is particularly useful when the ink solid content concentration rises inside the ink jet head 30 due to factors such as ink solvent evaporation and the ink solid components are likely to precipitate or settle. .

  In addition, since the ink in the ink bag of the ink tank has a relatively low ink flow rate, precipitation and sedimentation of solid components of the ink may occur inside the ink bag. For this reason, a stirrer (not shown) or the like may be installed below the ink tank, and a stirrer fluororesin-coated magnet (not shown) may be placed in the ink bag in advance. Thus, the ink in the ink bag can be continuously stirred regardless of whether the ink jet recording apparatus is in operation.

(Third embodiment)
A third embodiment of the present invention will be described below with reference to FIG. FIG. 3 is a schematic cross-sectional view showing a third embodiment of the ink jet recording apparatus of the present invention. As shown in FIG. 3, the ink jet recording apparatus according to this embodiment includes a first ink tank 10 and a second ink tank 20 as in the first embodiment. The first ink tank 10 is connected to the first supply path 15 and is connected to the ink supply flow path connection portion 31 of the inkjet head 30. The second ink tank 20 is connected to the ink supply flow path connection portion 32 of the inkjet head 30 via the second supply path 25. That is, the first ink tank 10 and the second ink tank 20 communicate with each other via the inkjet head 30 so that ink can be transferred.

  Furthermore, the ink jet recording apparatus according to the present embodiment includes an ink stirring channel 40 that communicates the first ink tank 10 and the second ink tank 20. The ink stirring path 40 directly connects the first ink tank 10 and the second ink tank 20 without using the inkjet head 30, and includes a two-way electromagnetic valve 41. The first ink supply channel 15 includes a two-way electromagnetic valve 16 and a two-way electromagnetic valve 26 installed in the ink supply channel 25.

  Normally, when the ink jet head is driven to eject ink, the two-way solenoid valve 41 is closed and the two-way solenoid valves 16 and 26 are opened. At this time, the difference between the pressures applied to the first ink tank 10 and the second ink tank 20 causes the ink flow to be generated in the ink supply flow path including the ink chamber 35 in the inkjet head 30, while A pressure within a range between a pressure applied to one ink tank 10 and a pressure applied to the second ink tank 20 is applied to the ink in the inkjet head, and the ink is ejected.

  In the ink jet recording apparatus according to the present embodiment, the solenoid valve 41 is periodically opened, and the ink difference in the ink stirring flow path 40 is determined using the pressure difference between the first ink tank 10 and the second ink tank 20. Transport. In this way, the ink flow is generated without flowing the ink through the ink supply flow path including the inside of the inkjet head. Thereby, stirring of the ink in an ink tank can be performed efficiently.

  At this time, by closing the electromagnetic valves 16 and 26 in the first and second flow paths, the ink in the ink bags 11 and 12 can be vigorously transferred through the ink stirring flow path. For this reason, it is possible to stir the ink in the ink bag more effectively, and it is possible to more reliably prevent precipitation and settling of the solid component in the ink containing the solid component and perform stable ink ejection. . Further, when the ink is stirred by generating an ink flow from the high pressure side to the low pressure side ink tank through the ink stirring channel 40, the ink is reciprocated in the ink stirring channel 40 by repeatedly switching the pressure of the ink tank. By doing so, the ink flow can be continuously generated.

  Further, since the solenoid valves 16 and 26 are closed and there is no pressure influence on the ink jet head, an ink flow having a faster flow rate can be generated in the ink stirring flow path 40. That is, by setting the pressure on the low pressure side in the ink tank to a lower pressure setting, setting the pressure on the high pressure side to a higher pressure setting, and increasing the pressure difference than when ink is transferred in the ink supply flow path including the inkjet head, A faster ink flow may be generated. Therefore, the ink in the ink bag can be stirred more effectively.

  Further, in order to make the flow rate of the ink flow in the ink stirring flow path 40 faster, the flow resistance of the ink stirring flow path 40 is set to the first ink supply in addition to the configuration in which the pressure difference between the ink tanks is set larger. You may employ | adopt the structure made smaller than the flow path resistance in the ink supply flow path containing the flow path, the inkjet head 30, and the 2nd ink supply flow path. Also with this configuration, since a large amount of ink flows into and out of the ink bag in a short time, the ink can be effectively stirred.

  Then, after the regular stirring of the ink through the ink stirring channel 40 is completed, the electromagnetic valve 41 is closed, leaving a small amount of ink of 10 cc or more in one ink bag (120 cc capacity), and setting the low pressure (−3 0.0 kPa), and a relatively large amount of ink of 110 cc or less is left in the other ink bag (120 cc capacity), and a high pressure setting (+1.0 kPa) is set. In this state, if the electromagnetic valves 16 and 26 are simultaneously opened, the state may be returned to the state in which the ink flow is generated in the ink supply flow path including the inside of the normal inkjet head 30.

  Further, in the ink jet recording apparatus of the present embodiment, after the ink flow passing through the ink jet head 30 from the first ink tank 10 and flowing to the second ink tank 20 is generated, the ink in the first ink tank is discharged. If the solenoid valves 16 and 26 are closed before the exhaustion is completed, and the solenoid valve 41 is opened to switch the pressure, the ink in the second ink tank can be returned to the first ink tank via the ink stirring channel 40. Thereby, it is possible to fix the ink flow of the ink supply flow path including the inside of the inkjet head in one direction. As a result, even if the flow resistance of the ink flow in the ink supply flow path is different between upstream and downstream, a constant ink flow can be generated. Control can be performed more stably.

  Here, the configuration of the inkjet head 30 mounted in the inkjet recording apparatus of the present invention will be described with reference to FIG. The inkjet head 30 is configured by bonding two piezoelectric substrates (not shown) in a state where the polarization directions face each other, and performing a plurality of rows of grooves in the depth direction of FIG. Inside this one groove (ink chamber 35), an electrode material such as Cu is formed as a driving electrode using a sputtering technique, and the external circuit and the driving electrode are anisotropically bonded to a flexible printed circuit board (not shown). Electrical connection is made using an agent or the like. The ink chamber 35 is surrounded by two channel walls extending in the left-right direction shown in FIG. 1 where an ink flow is generated and a nozzle plate 37, and communicates with the two common ink chambers 33 and 34.

  When an electric field is applied to the electrodes formed inside the opposing channel walls in the ink chamber 35, the channel walls are driven in a shear mode at the center in the depth direction of the channel walls formed by bonding two opposing piezoelectric materials. Is deformed into a “<” shape, and an ink pressure wave is generated in the ink chamber 35. Thus, energy is applied to the ink, and ink droplets are ejected from the nozzle holes 36 formed in the nozzle plate 37 bonded to the upper surface of the channel wall.

(Fourth embodiment)
In the above-described embodiment, the ink flow is generated in the ink supply flow path including the ink pressure chamber. In the piezoelectric shear mode type ink jet head, in addition to the above top shooter type head (roof shooter type head), A side shooter type head (edge shooter type head) in which a plurality of ink chambers are extended from one common ink chamber as shown in FIG. 4, a thermal ink jet head, a laminated piezoelectric ink jet head, or the like is applicable. By using the present invention, it is possible to realize high-precision printing, improved device reliability, and improved device production yield in a film forming process for printing and device manufacturing.

  A fourth embodiment of the present invention will be described below with reference to FIG. FIG. 4 is a schematic cross-sectional view of the side shooter head that is driven in the piezoelectric shear mode and the ink supply channel in a direction parallel to the ink chamber row. As shown in FIG. 4, a plurality of ink chambers 38 extend from one common ink chamber 39 and are arranged in parallel on the inkjet head 30. In the ink chamber 38, the common ink chamber 39 side is at the tip on the counter electrode side. A nozzle plate 37 on which the nozzles 36 are formed is bonded. The ink chamber 38 is surrounded by a channel wall made of a piezoelectric material and a cover member (not shown). Like the top shooter type head, the ink chamber 38 shares the channel wall by applying a voltage to the electrode on the inner surface of the ink chamber 39 of the channel wall. By causing mode deformation, an ink shock wave is generated in the ink chamber 39 and ink is ejected.

  In the ink jet recording apparatus shown in FIG. 4, the ink flow generated by the pressure difference between the first and second ink tanks 10 and 20 flows in the common ink chamber 39 inside the ink jet head 30 in the direction of the arrow shown in FIG. For this reason, an ink flow cannot be directly generated in the ink chamber 38. However, since the ink in the ink chamber 38 is substantially discharged from the nozzle hole 36 in a relatively short time by ink discharge, the ink flow in the common ink chamber 39 in the immediate vicinity of the ink chamber 38 is sufficient. The ink can be stirred. As a result, sufficient ink ejection reliability can be ensured in a film forming process and a printing process in device manufacture.

  In each of the above-described embodiments, the height positions of the ink bag and the inkjet head are the same. However, the ink bag may be disposed at a position higher than the inkjet head, and the ink in a plurality of ink tanks The bags may be arranged at different positions. The extra head pressure from the nozzle position of the inkjet head to each ink bag will be applied, but subtract the extra head pressure from the set pressure when the ink tank and inkjet head are at the same height. The ink flow can be generated satisfactorily by correcting the pressure and adjusting the pressure of each ink tank.

Further, in each of the above-described embodiments, the pressure in the ink tank is switched using a pressure adjusting pump as a pressure control unit. However, the heights of the plurality of ink tanks with respect to the nozzle height position of the inkjet head are used. By controlling the position, the ink flow can be generated using the water head difference from each ink tank to the head. For example, when a constant negative pressure of −15 cmH ₂ O (−15 cm ink) with respect to atmospheric pressure is applied to the nozzle position, the flow path resistance between the inkjet head and the first ink tank, the inkjet head, and the second ink When the flow path resistance between the tanks is substantially the same, the first ink tank is disposed at a position 10 cm higher than the nozzle position, and the second ink tank is disposed at a position 40 cm lower than the nozzle position. The pressure difference can be generated. At this time, as the pressure control means, a slider mechanism or the like for moving the height position of the ink tank up and down with respect to the nozzle position origin is assumed.

  In each of the above-described embodiments, the flow path resistance of each ink flow path from the plurality of ink tanks to the ink jet head is substantially the same, but the ink supply flow path from the ink jet head to each ink tank is the same. Even if the flow path resistance is different, the flow path resistance is calculated from the three-dimensional shape of each ink flow path, or the flow resistance (pressure loss) is obtained by running ink experimentally in individual ink flow paths. May be obtained experimentally. By considering how each channel resistance of the plurality of ink supply channels affects the ink channel (whether the ink flow is upstream of the ink jet head position or the ink flow is downstream), the ink It is possible to adjust the pressure setting values in the forward and backward flow directions and generate an ink flow with a constant negative pressure applied to the inkjet head at all times.

  In order to effectively stir the ink, it is desirable to ensure a sufficient ink flow rate in the ink flow path with respect to ink consumption due to ink ejection from the inkjet head. When the ink jet recording apparatus according to the present invention is applied to a device manufacturing process and continuously operated, an injection needle (inner diameter φ0.8 mm × 10 mm length) and electromagnetic that are the narrowest part in an ink supply flow path of ink containing plastic beads Table 1 shows the aging test results until clogging failure occurs in the valve (φ1.0 × 12 mm length including bending).

  As shown in Table 1, even when a relatively large amount of ink flow (0.5 cc / min) is generated in the apparatus due to outflow of ink, in a state where no ink flow is generated in the flow path, It was found that the solid component contained in the ink was precipitated and settled on the seventh day from the operation of the apparatus, which is not suitable for continuous operation of the apparatus (Test 1). Also, if the ink outflow amount is the same as in Test 1 (0.5 cc / min) and an ink flow having the same flow rate as the outflow amount is generated, the period until clogging occurs in the injection needle or solenoid valve is extended. However, clogging occurred on the 10th day after the operation of the apparatus, which was not suitable for continuous operation of the apparatus (Test 2).

  Therefore, in Test 3, the ink flow rate was doubled (1.0 cc / min) of the ink outflow rate, and the period from operation to clogging was tested as described above. At this time, clogging occurred 90 days after the operation of the apparatus, but it was possible to adapt to continuous operation of the apparatus by maintaining the apparatus about every 60 days and eliminating the clogging. Furthermore, in Test 4, when an ink flow with an ink flow rate (1.5 cc / min) that is three times the amount of ink outflow is generated, the period until clogging is further extended, from operation to the 230th day. Without clogging, the apparatus could be operated continuously and effectively with apparatus maintenance every 200 days.

  Also, in Test 5 and Test 6, when the ink flow rate was 10 times (5.0 cc / min) and 20 times (10.0 cc / min) of the ink outflow, no clogging occurred during the test period. Although it is impossible to calculate an accurate maintenance frequency, it can be determined that it is suitable for long-term continuous operation. From the above test results, when the apparatus is continuously operated, it is desirable to generate an ink flow with an ink flow rate of at least twice as large as the ink outflow amount, and it is further desirable to generate an ink flow with an ink flow rate of 3 times or more. . Further, by generating an ink flow having an ink amount of 10 times or more the ink outflow amount, an effect of preventing precipitation and sedimentation of an ink-containing solid component that can sufficiently withstand long-term continuous operation as a device manufacturing apparatus can be realized.

  The ink jet recording apparatus according to the present invention is not limited to the above-described embodiment. In the ink jet recording apparatus provided with the ink jet head and the ink supply flow path, the ink jet recording apparatus is different from a plurality of ink tanks and a plurality of ink tanks. By providing a pressure generating means for generating pressure and a pressure switching means, the same characteristic effect is exhibited.

(Effect of the present invention)
The effect by this invention can also be expressed as follows.

  (1) A recording apparatus having an ink jet head for discharging ink has a plurality of ink tanks connected to the ink jet head through an ink flow path, and means for generating different pressures in the plurality of ink tanks. In addition, since the pressure switching means for switching the pressures of the plurality of ink tanks is provided, different pressures (water head difference levels) can be applied to the inks in the plurality of ink tanks, so that the ink generated between the plurality of ink tanks Due to the pressure difference (water head difference), the ink tank communicates from the ink tank to which high pressure is applied (ink tank with higher water head difference) to the ink tank to which low pressure is applied (ink tank with lower water head difference). Ink flows through the ink flow path. At this time, the ink flow path communicating between the plurality of ink tanks includes an ink flow path inside the inkjet head, specifically, an ink flow path such as a common ink chamber or an ink pressurizing chamber. Since the ink flow can generate an ink flow in the ink flow path and all areas where the ink is present in the ink jet head, the solid components are aggregated and settled even if the ink used is a solid component ink. Can be prevented. In addition, since it has means for changing the pressure of the ink by switching the pressure applied to the plurality of ink tanks, the pressure of the ink in the high pressure ink tank is changed before the ink in the ink tank of the low pressure flows out. By changing the ink pressure of multiple ink tanks so that a low pressure is applied to the ink tank that was at a high pressure, while a high pressure is applied to the ink tank that was at a low pressure, Since the ink flow can be generated in all the ink supply flow paths including the ink flow path, the ink can be effectively stirred by the ink flow. Also, the ink flow stops only when the ink pressures of the plurality of ink tanks are all equal, and the ink flow hardly stops. Therefore, the solid components contained in the ink are effectively aggregated and settled. In particular, when there are two or more ink tanks, it is possible to completely avoid the stopped state of the ink flow by switching the ink tank pressure without setting all of them to the same pressure.

  (2) The ink jet recording apparatus includes: a first ink flow path connecting portion and a second ink flow path connecting portion of the ink jet head; a first ink tank communicating with the first ink flow path connecting portion; The inkjet head comprising a second ink tank communicating with the second ink flow path connecting portion and located between the ink flow paths connecting the first ink tank and the second ink tank is the inkjet head. The flow path resistance R1 in the ink flow path from the first ink tank to the first ink tank and the flow path resistance R2 in the ink flow path to the second ink tank are substantially the same, and the constant pressure P1 and the first pressure are applied to the ink in the first ink tank. An ink pressure of a constant pressure P2 was applied to the ink in the ink tank 2, and an intermediate value pressure P3 between P1 and P2 was always applied to the ink inside the ink jet head. As in (1), the ink flow can generate an ink flow in the ink flow path and in all areas where the ink is present in the ink jet head. Precipitation and sedimentation can be prevented. In addition, the flow path resistance is substantially reduced by making the structure of the ink flow path from the first and second ink tanks to the inkjet head (three-dimensional structure such as flow path length, flow path cross-sectional area and bent shape) substantially the same. Therefore, even if the flow resistance value of the actual ink supply flow path is not obtained, the pressure applied to the ink jet head is an intermediate value between the ink pressures of the first and second ink tanks. Since the ink pressure setting is easy, the ink pressure control of the ink jet recording apparatus can be easily performed, and the maintainability of the ink jet recording apparatus is improved.

  (3) The ink jet recording apparatus applies a constant pressure P1 to the ink in the first ink tank and an ink pressure of a constant pressure P2 to the ink in the second ink tank, and sets an intermediate value pressure P3 between P1 and P2. Since ink is ejected by driving the ink jet head when it is constantly applied to the ink inside the ink jet head, the ink flow is the same as in (1). Since the ink flow can be generated in the region, it is possible to prevent aggregation and precipitation of the solid component even in the case of the ink containing the solid component. Further, ink is ejected by driving the ink jet head in a state where an ink flow is generated in the ink flow path including the inside of the ink jet head between the two ink tanks and a constant pressure P3 is constantly applied to the ink jet head. Therefore, it is possible to prevent aggregation and sedimentation of solid components contained in the ink, and to stabilize the ink ejection characteristics such as ejection speed and ejection volume by driving the inkjet head at a constant ink pressure. Can improve device production yield.

  (4) The ink jet recording apparatus applies a constant pressure P1 to the ink in the first ink tank and an ink pressure of the constant pressure P2 to the ink in the second ink tank, and the first or first pressure varies depending on the pressure difference between P1 and P2. The ink is caused to flow out of the second ink tank and the constant pressure value P3 between P1 and P2 is held as the ink pressure in the inkjet head while the ink is allowed to flow into the second or first ink tank, and the first or Before the ink in the second ink tank runs out, the constant pressure P2 is applied to the ink in the first ink tank and the constant pressure P1 is applied to the ink in the second ink tank so that the ink pressure in the inkjet head is set to P3. The first and second ink pressures of the first ink tank and the ink pressure of the second ink tank are switched in two steps, respectively. Since the ink flows back and forth between the ink tank and the ink tank, the ink flow can be generated in all areas where the ink exists in the ink flow path and the inkjet head, as in (1). Even ink containing a solid component can prevent aggregation and sedimentation of the solid component. Also, when flowing ink from a high ink pressure ink tank to a low ink pressure ink tank, before the ink in the high ink pressure ink tank runs out, a low pressure change is made to the high ink pressure ink tank. Since the ink flow can be generated so that the ink moves back and forth between the two ink tanks by making a high pressure change in the ink tank with a low ink pressure, the ink flow is surely generated without almost stopping. And efficient ink agitation can be realized.

  (5) The ink jet recording apparatus sets the ink pressures of the first and second ink tanks in two stages of P1 and P2, and the ink pressures of the ink tanks are alternately set to the ink pressures of the other ink tanks. In the process of switching, the ink pressure in the first and second ink tanks is changed while maintaining the intermediate pressure P3 of the ink pressure in the first and second ink tanks, and the ink tank is set in the process of switching the ink tank set pressure in the process of switching. In order to maintain the ink pressure P3, the ink flow can generate an ink flow in all areas where the ink exists in the ink flow path and the inkjet head, as in (1). Even so, aggregation and precipitation of solid components can be prevented. In addition, when switching the pressures of the two ink tanks, the pressure of the first ink tank starts to change simultaneously while balancing the ink pressures of the ink tanks so that the ink pressure in the ink jet head is always P3. The value, the pressure value of the second ink tank, and the pressure value of the ink in the ink jet head are all P3 (if there is a height difference (water head difference) in the ink tank and ink jet head mounting position, the pressure setting considering the water head difference is necessary. The ink-jet head can maintain a state where a constant pressure is applied even when the ink pressure is switched, and the ink-jet head can always discharge under a constant pressure condition. Therefore, the pressure of the ink supply system and the mechanism that generates the ink flow in the ink tank Control the inkjet head need absolutely no to work together or synchronous operation a drive control of maintenance of the ink jet recording apparatus is improved.

  (6) The ink jet recording apparatus includes: a first ink flow path connecting portion and a second ink flow path connecting portion of the ink jet head; a first ink tank communicating with the first ink flow path connecting portion; The inkjet head, which includes a second ink tank communicating with the second ink channel connection portion and is located between the ink channels connecting the first ink tank and the second ink tank, is the inkjet head. The flow resistance R1 in the ink flow path from the first ink tank to the first ink tank and the flow resistance R2 in the ink flow path to the second ink tank, and a constant pressure that satisfies P4> P3 ′ in the ink in the first ink tank An ink pressure of a constant pressure P5 that satisfies P5 <P3 ′ is applied to P4 and the ink in the second ink tank, and the ink is transferred from the first ink tank to the second ink tank. This is applied, and a constant pressure P6 that satisfies P6 <P3 ′ and a constant pressure P7 that satisfies P7> P3 ′ are applied to the ink in the first ink tank, and the second pressure is applied to the second ink. When an ink flow is generated from the ink tank to the first ink tank, the ink pressure inside the inkjet head is P3 ′, and (P4−P3 ′) / R1 = (P3′−P5) / R2 and (P3 '-P6) / R1 = (P7-P3') / R2 P4 and P6 are set as the ink pressure of the first ink tank, and the pressure is set in two stages, and P5 and P7 are set as those of the second ink tank. Since the ink pressure has a two-stage pressure setting as the ink pressure, and has a pressure switching means for switching the ink pressures of the first and second ink tanks with different two-stage pressure settings, the ink flow is the same as in (1). Since it is possible to generate ink flow in all areas where there is ink in the ink flow path and an ink jet head, it is possible to prevent aggregation precipitation and sedimentation of solid components be ink containing solid component. In addition, even when the shapes of the two ink flow paths leading to the two ink tanks extended from the ink jet head due to various restrictions are different, it is possible to achieve stable ink agitation and constant pressure application to the ink in the ink jet head. be able to.

  (7) The ink jet recording apparatus applies a constant pressure P4 or P6 to the ink in the first ink tank and an ink pressure of a constant pressure P5 or P7 to the ink in the second ink tank, and sets the constant pressure P3 ′. Since ink is ejected by driving the ink jet head when it is constantly applied to the ink inside the ink jet head, the ink flow is the same as in (1). Since the ink flow can be generated in the region, it is possible to prevent aggregation and precipitation of the solid component even in the case of the ink containing the solid component. Further, as in (3), the ink jet is generated while an ink flow is generated in the ink flow path including the inside of the ink jet head between the two ink tanks, and the constant pressure P3 ′ is constantly applied to the ink jet head. Since ink is ejected by driving the head, aggregation and precipitation of solid components contained in the ink are prevented, and ink ejection characteristics such as ejection speed and ejection volume by driving the inkjet head at a constant ink pressure are stabilized. Therefore, it is possible to improve the device production yield in the device manufacturing process.

  (8) The ink jet recording apparatus applies a constant pressure P4 or P6 to the ink in the first ink tank and an ink pressure of the constant pressure P5 or P7 to the ink in the second ink tank, and P4 and P5 or P6 and P7. The pressure difference P3 ′ causes the ink to flow out from the first or second ink tank, and the constant pressure value P3 ′ is held as the ink pressure in the inkjet head while flowing the ink into the second or first ink tank. Before the ink in the first or second ink tank is exhausted, the pressure in the first ink tank is changed from the constant pressure P4 to P6 or the pressure change from P6 to P4, and the ink in the second ink tank is changed from the constant pressure P5. The pressure is switched to P7 or from P7 to P5, and the ink pressure in the inkjet head is changed to P3 ′. In order to cause the ink to reciprocate between the first and second ink tanks by switching the set pressure between the ink pressure of the first ink tank and the ink pressure of the second ink tank in two steps, respectively, As in (1), since the ink flow can be generated in all areas where the ink flow path and the ink in the ink jet head exist, the solid component coagulates and precipitates even if the ink contains a solid component. And settling can be prevented. Similarly to (4), when ink flows from the high ink pressure ink tank to the low ink pressure ink tank, the ink in the high ink pressure ink tank is low before the ink in the high ink pressure ink tank runs out. Since the ink flow can be generated so that the ink moves back and forth between the two ink tanks by changing the pressure and simultaneously changing the high pressure in the ink tank with the low ink pressure, the ink flow is almost stopped. Therefore, the ink can be reliably generated and efficient ink agitation can be realized.

  (9) The ink jet recording apparatus sets the ink pressure of the first and second ink tanks in two stages of P4 and P6 and P5 and P7, respectively, and switches the ink pressure of the ink tank in the ink jet head. Since the ink pressures in the first and second ink tanks are changed while maintaining the constant pressure P3 ′ in the ink, the ink flow is the same as in (1), in which all the ink in the ink flow path and the ink jet head exists. Since the ink flow can be generated in the region, it is possible to prevent aggregation and precipitation of the solid component even in the case of the ink containing the solid component. In addition, when switching the pressures of the two ink tanks as in (5), the pressure of the ink in the ink jet head always starts to change the pressure while balancing the ink pressures of the respective ink tanks so that the pressure is always P3 ′. The pressure value of the first ink tank, the pressure value of the second ink tank, and the pressure value of the ink in the ink jet head are all P3 (if there is a height difference (water head difference) in the ink tank and ink jet head mounting position, the water head difference Pressure setting in consideration of pressure), the ink jet head can maintain a state where a constant pressure is applied even when the ink pressure is switched, and the ink jet head is always constant. Since it can be discharged under pressure conditions, a mechanism for generating ink flow in the ink tank and Ink supply system requires absolutely no to work together or synchronous operation a drive control of the pressure control and the inkjet head, the maintenance of the inkjet recording apparatus is improved.

  (10) Since the ink jet recording apparatus sets the ink pressure inside the ink jet head to a negative pressure, the ink flow is the same in (1) as in the ink flow path and all the areas where the ink inside the ink jet head exists. Since the ink flow can be generated, the aggregation and precipitation of the solid component can be prevented even if the ink includes the solid component. Further, in order to apply a negative pressure to the ink inside the inkjet head, the meniscus of the ink formed at the tip of the nozzle disposed in the inkjet head is subjected to a surface treatment so that the outside of the nozzle has liquid repellency, and the nozzle If the inside is a lyophilic nozzle, if the ink pressure of the head is positive, ink will overflow abnormally outside the nozzle due to ink ejection from the inkjet head or residual vibration of the ink meniscus after ink ejection. Therefore, stable ink jet recording can be performed, and device production yield can be improved in device manufacturing using the ink jet recording apparatus.

  (11) In the ink jet recording apparatus, since the ink pressure P3 or P3 ′ inside the ink jet head is held within a range of ± 0.5 kPa with respect to the set pressure, the ink flow is the same as in (1). Since the ink flow can be generated in all areas where the ink is present in the flow path and the ink jet head, the solid component can be prevented from aggregating and sedimenting even if the ink includes the solid component. In addition, the ink pressure in the ink jet head is controlled in the range of ± 0.5 kPa while stirring the ink by the ink flow in the ink flow path including the inside of the ink jet head, so that the ink is discharged without changing the ink jet head drive conditions Ink ejection stability of about ± 2% at the speed and about ± 3% of the ink ejection volume can be ensured, and the device production yield can be improved in the device production process using the ink jet recording apparatus.

  (12) In the ink jet recording apparatus, the ink flow rate per unit time due to the ink pressure difference between the plurality of ink tanks in the ink jet head is more than twice the ink consumption per unit time due to the ink ejection of the ink jet head. Therefore, as in (1), the ink flow can generate an ink flow in all areas where ink exists in the ink flow path and the ink jet head. Aggregation precipitation and sedimentation can be prevented. In addition, even when ink is ejected by driving the ink-jet head and an ink flow is generated in the ink supply flow path and ink to be circulated is consumed by ink ejection, a sufficient ink flow can be ensured, so it is safer. It is possible to prevent precipitation and sedimentation of solid components contained in the ink.

  (13) Since the ink jet recording apparatus has a structure in which the ink in the plurality of ink tanks does not come into contact with air other than the nozzle holes of the ink jet head, the ink flow is the same as in the ink flow path and the ink jet head as in (1). Since the ink flow can be generated in all the areas where the internal ink exists, the aggregation and precipitation of the solid component can be prevented even with the ink containing the solid component. Further, since the ink used does not come into contact with air in the ink supply system of the ink tank and the ink flow path, the deaerated ink can be used stably, and the ink can be stirred while the air is shut off. It is possible to simultaneously prevent precipitation and settling of solid components and high-frequency driving stability, and even when this inkjet recording apparatus is applied to device manufacture, device productivity can be further improved.

  (14) The ink jet recording apparatus includes a first two-way valve provided in a first ink flow path connecting the ink jet head and the first ink tank, and the ink jet head and the second ink tank. A second two-way valve provided in the second ink flow path to be connected, a third ink flow path communicating with the first and second ink tanks without passing through the inkjet head, and a third ink flow path Since the third two-way valve is provided in the ink flow, the ink flow can be generated in all areas where the ink exists in the ink flow path and the ink jet head as in (1). Even in the case of ink containing a solid component, aggregation and precipitation of the solid component can be prevented. In addition, since the third ink flow path that does not pass through the inkjet head that connects the first ink tank and the second ink tank is provided, the first and second two-way valves are periodically closed, 3 to open the two-way valve and generate an ink flow using the difference in pressure between the first ink tank and the second ink tank without passing through the inkjet head. The ink in the ink tank where the ink flow continues for a long time can be selectively stirred, and even if the ink contains solid components in all areas where ink exists more effectively, Aggregation precipitation and sedimentation can be prevented.

  (15) The inkjet recording apparatus periodically opens a third two-way valve provided in a third ink flow path communicating with the first and second ink tanks, and the inkjet head and the first ink The first two-way valve provided in the first ink flow path connecting the tank is closed, and the second two-way provided in the second ink flow path connecting the inkjet head and the second ink tank Since the valve is closed and the ink in the first and second ink tanks is transferred unidirectionally or alternately, the ink flow is the same as in (1) and (14). Since the ink flow can be generated in all the areas, the solid component can be prevented from aggregating and settling even with the ink containing the solid component. In addition, since the third ink flow path that does not pass through the inkjet head that connects the first ink tank and the second ink tank is provided, the first and second two-way valves are periodically closed, 3 to open the two-way valve and generate an ink flow using the difference in pressure between the first ink tank and the second ink tank without passing through the inkjet head. The ink in the ink tank where the ink flow continues for a long time can be selectively stirred, and even if the ink contains solid components in all areas where ink exists more effectively, Aggregation precipitation and sedimentation can be prevented. Further, since the high pressure and the low pressure are alternately switched and applied to the respective ink tanks using the pressure switching means of the first and second ink tanks, the ink reciprocates between the ink tanks. In addition, the ink agitation time of the ink tank or the number of ink transfer reciprocations can be set, so even if the ink contains particles that have a relatively high sedimentation speed, the ink can be used stably by setting a large number of ink reciprocations. In addition, it is possible to widen the characteristic range related to sedimentation or precipitation of ink that can be used by the ink jet recording apparatus.

  (16) In the ink jet recording apparatus, the first ink in which the flow path resistance R3 of the third ink flow path communicating with the first and second ink tanks connects the ink jet head and the first ink tank. Since it is smaller than the sum (R1 + R2) of the flow path resistance R1 of the flow path and the flow path resistance R2 of the second ink flow path connecting the inkjet head and the second ink tank, the same as in (1) and (14) In addition, since the ink flow can be generated in all areas where the ink exists in the ink flow path and the ink jet head, the solid component can be prevented from aggregating and settling even if the ink contains the solid component. be able to. In addition, since the third ink flow path that does not pass through the inkjet head that connects the first ink tank and the second ink tank is provided, the first and second two-way valves are periodically closed, 3 to open the two-way valve and generate an ink flow using the difference in pressure between the first ink tank and the second ink tank without passing through the inkjet head. The ink in the ink tank where the ink flow continues for a long time can be selectively stirred, and even if the ink contains solid components in all areas where ink exists more effectively, Aggregation precipitation and sedimentation can be prevented. Further, since the flow resistance of the third ink flow path connecting the first and second ink tanks without passing through the ink jet head is smaller than the flow resistance of the ink flow path passing through the ink jet head, the third When an ink flow is generated in the ink flow path, a large ink flow rate can be secured, ink stirring of the ink tank can be performed more effectively, and ink containing particles having a relatively high sedimentation speed can be obtained. By vigorously stirring the ink in the ink tank, it is possible to stably use the ink, and it is possible to widen the characteristic range relating to ink sedimentation or precipitation that can be used by the ink jet recording apparatus.

  (17) The ink jet recording apparatus is configured to transfer the ink in the first and second ink tanks in one direction or alternately via a third ink flow path communicating with the first and second ink tanks. The pressure difference P10 = P8−P9 (P8> P9) between the ink pressure P8 or P9 of the first ink tank and the ink pressure P9 or P8 of the second ink tank applied to the first ink channel, The first and second inks when the ink is pumped from the first ink tank to the second ink tank or when the ink is pumped from the second ink tank to the first ink tank via the two ink flow paths and the inkjet head. Since the ink pressure difference P11 of the ink tank 2 is larger than the ink pressure difference P11, the ink flow in the ink flow path and the ink jet head is the same as in (1) and (14). Since There can be generated ink flow in all the regions present, it is possible to prevent coagulation sedimentation and sedimentation of solid components be ink containing solid component. In addition, since the third ink flow path that does not pass through the inkjet head that connects the first ink tank and the second ink tank is provided, the first and second two-way valves are periodically closed, 3 to open the two-way valve and generate an ink flow using the difference in pressure between the first ink tank and the second ink tank without passing through the inkjet head. The ink in the ink tank where the ink flow continues for a long time can be selectively stirred, and even if the ink contains solid components in all areas where ink exists more effectively, Aggregation precipitation and sedimentation can be prevented. Further, the ink of each ink tank to be applied when generating an ink flow for stirring the ink in the ink tank in the third ink flow path that communicates the first and second ink tanks without going through the ink jet head. Since the pressure difference is set to a large pressure and larger than the ink tank pressure difference at the time of ink flow generation in the ink flow path (first and second ink flow paths) via the ink jet head, ink is supplied to the third ink flow path. When generating a flow, a large ink flow rate can be secured, ink stirring in the ink tank can be carried out more effectively, and ink stirring can be performed vigorously even for ink containing particles having a relatively high sedimentation speed. The ink can be used stably, and the ink settling or precipitation that can be used by the ink jet recording apparatus That characteristic range can be widened.

(Other configurations)
The present invention can also be expressed as follows.

(First configuration)
In a recording apparatus having an inkjet head for discharging ink, the recording apparatus includes a plurality of ink tanks connected to the inkjet head through an ink flow path, and means for generating different pressures in the plurality of ink tanks, and An ink jet recording apparatus comprising pressure switching means for switching the pressures of a plurality of ink tanks.

(Second configuration)
The ink jet recording apparatus includes: a first ink channel connecting portion and a second ink channel connecting portion of the ink jet head; a first ink tank communicating with the first ink channel connecting portion; and the second ink channel connecting portion. The ink jet head, which is provided between the ink flow path connecting the first ink tank and the second ink tank, includes a second ink tank communicating with the ink flow path connecting portion. The flow path resistance R1 in the ink flow path to the first ink tank and the flow path resistance R2 in the ink flow path to the second ink tank are substantially the same, and the constant pressure P1 and the second ink are applied to the ink in the first ink tank. The ink pressure of a constant pressure P2 is applied to the ink in the tank, and the intermediate pressure P3 between P1 and P2 is always applied to the ink inside the ink jet head. The ink jet recording apparatus according to the first configuration to.

(Third configuration)
The ink jet recording apparatus applies a constant pressure P1 to the ink in the first ink tank and an ink pressure of a constant pressure P2 to the ink in the second ink tank, and always applies an intermediate pressure P3 between P1 and P2 to the ink. The ink jet recording apparatus according to the first or second configuration, wherein the ink jet head is driven to eject ink when applied to ink inside the head.

(Fourth configuration)
The ink jet recording apparatus applies a constant pressure P1 to the ink in the first ink tank and an ink pressure of the constant pressure P2 to the ink in the second ink tank, and the first or second ink is determined by the pressure difference between P1 and P2. A constant pressure value P3 between P1 and P2 is maintained as the ink pressure in the ink jet head while the ink is allowed to flow out of the tank and the ink is allowed to flow into the second or first ink tank. Before the ink in the ink tank is exhausted, the first pressure P2 is applied to the ink in the first ink tank and the constant pressure P1 is applied to the ink in the second ink tank, and the ink pressure in the inkjet head is set to P3. The ink pressure in the first ink tank and the ink pressure in the second ink tank are switched in two steps, respectively, and the first and second ink tanks are switched. The first ink jet recording apparatus according to the second and third configuration, wherein the reciprocating flow of ink between the ink tank.

(Fifth configuration)
In the ink jet recording apparatus, the ink pressures of the first and second ink tanks are set in two stages of P1 and P2, and the ink pressures of the ink tanks are alternately switched so as to be the ink pressures of the other ink tanks. The ink pressure in the inkjet head in the process of changing the ink tank set pressure by changing the ink pressure in the first and second ink tanks while maintaining the intermediate pressure P3 of the ink pressure in the first and second ink tanks. The inkjet recording apparatus according to any one of the first, second, third, and fourth configurations, wherein P3 is held.

(Sixth configuration)
The ink jet recording apparatus includes: a first ink channel connecting portion and a second ink channel connecting portion of the ink jet head; a first ink tank communicating with the first ink channel connecting portion; and the second ink channel connecting portion. The ink jet head, which is provided between the ink flow path connecting the first ink tank and the second ink tank, includes a second ink tank communicating with the ink flow path connecting portion. The flow resistance R1 in the ink flow path to the second ink tank and the flow resistance R2 in the ink flow path to the second ink tank are set to a constant pressure P4 and P4> P3 ′ for the ink in the first ink tank. An ink pressure of a constant pressure P5 that satisfies P5 <P3 ′ is applied to the ink in the ink tank 2 to generate an ink flow from the first ink tank to the second ink tank. In addition, an ink pressure of a constant pressure P6 satisfying P6 <P3 ′ and an ink pressure of P7> P3 ′ satisfying P7> P3 ′ is applied to the ink in the first ink tank, and the second ink tank. When the ink flow is generated in the first ink tank, the ink pressure inside the inkjet head is P3 ′, and (P4−P3 ′) / R1 = (P3′−P5) / R2 and (P3′−P6). ) / R1 = (P7−P3 ′) / R2, P4 and P6 are set as the ink pressure of the first ink tank, and the pressure is set in two stages, and P5 and P7 are set as the ink pressure of the second ink tank. 2. An ink jet apparatus according to a first configuration, comprising pressure switching means having a two-stage pressure setting and switching the ink pressures of the first and second ink tanks with different two-stage pressure settings. Recording apparatus.

(Seventh configuration)
The ink jet recording apparatus applies a constant pressure P4 or P6 to the ink in the first ink tank and an ink pressure of a constant pressure P5 or P7 to the ink in the second ink tank, and always applies the constant pressure P3 ′ to the ink. The ink jet recording apparatus according to any one of the first and sixth configurations, wherein the ink jet head is driven to eject ink when applied to the ink inside the head.

(Eighth configuration)
The ink jet recording apparatus applies a constant pressure P4 or P6 to the ink in the first ink tank and a constant pressure P5 or P7 to the ink in the second ink tank, and a pressure difference between P4 and P5 or P6 and P7. To cause the ink to flow out of the first or second ink tank, and hold the constant pressure value P3 ′ as the ink pressure in the ink jet head while flowing the ink into the second or first ink tank. Before the ink in the second ink tank is exhausted, the pressure in the first ink tank is changed from the constant pressure P4 to P6, or the pressure is switched from P6 to P4, and the ink in the second ink tank is changed from the constant pressure P5 to P7. Alternatively, switch the pressure from P7 to P5 and set the ink pressure in the inkjet head to P3 ′. In addition, the ink pressure in the first ink tank and the ink pressure in the second ink tank are switched in two steps, respectively, and the ink is reciprocated between the first and second ink tanks. The ink jet recording apparatus according to any one of the first, sixth, and seventh configurations.

(Ninth configuration)
The ink jet recording apparatus sets the ink pressure of the first and second ink tanks in two stages, P4 and P6, and P5 and P7, respectively, and in the process of switching the ink pressure of the ink tank, The ink jet recording apparatus according to any one of the first, sixth, seventh, and eighth configurations, wherein the ink pressure of the first and second ink tanks is changed while maintaining a constant pressure P3 '.

(Tenth configuration)
The first, second, third, fourth, fifth, sixth, seventh, eighth and ninth are characterized in that the ink jet recording apparatus sets the ink pressure inside the ink jet head to a negative pressure. The inkjet recording apparatus as described in the structure.

(Eleventh configuration)
In the ink jet recording apparatus, the ink pressure P3 or P3 ′ inside the ink jet head is maintained in a range of ± 0.5 kPa with respect to a set pressure, wherein the first, second, third, fourth, The ink jet recording apparatus according to any of the fifth, sixth, seventh, eighth, ninth and tenth configurations.

(Twelfth configuration)
In the inkjet recording apparatus, an ink flow rate per unit time due to an ink pressure difference between a plurality of ink tanks in the inkjet head is at least twice an ink consumption amount per unit time due to ink ejection of the inkjet head. The inkjet recording apparatus according to any of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth and eleventh configurations.

(13th configuration)
The ink jet recording apparatus has a structure in which the ink in the plurality of ink tanks does not come into contact with air except at the nozzle hole portion of the ink jet head, wherein the first, second, third, fourth, fifth, The ink jet recording apparatus according to any one of the sixth, seventh, eighth, ninth, tenth, eleventh and twelfth configurations.

(14th configuration)
The ink jet recording apparatus includes: a first two-way valve provided in a first ink flow path connecting the ink jet head and the first ink tank; and a first two way valve connecting the ink jet head and the second ink tank. A second two-way valve provided in the second ink flow path, a third ink flow path communicating with the first and second ink tanks without passing through the ink jet head, and a third ink flow path. A first two-way valve, a first, a second, a third, a fourth, a fifth, a sixth, a seventh, an eighth, a ninth, a tenth, an eleventh, and a twelfth. And an ink jet recording apparatus according to the thirteenth configuration.

(15th configuration)
The ink jet recording apparatus periodically opens a third two-way valve provided in a third ink flow path communicating with the first and second ink tanks, and connects the ink jet head and the first ink tank. The first two-way valve provided in the first ink flow path to be connected is closed, and the second two-way valve provided in the second ink flow path to connect the inkjet head and the second ink tank is closed. The ink jet recording apparatus according to the fourteenth configuration, wherein the ink in the first and second ink tanks is unidirectionally or alternately transferred.

(Sixteenth configuration)
In the ink jet recording apparatus, a flow path resistance R3 of a third ink flow path that communicates the first and second ink tanks has a first ink flow path that connects the ink jet head and the first ink tank. In the fourteenth and fifteenth configurations, the flow resistance R1 is smaller than the sum (R1 + R2) of the flow resistance R2 of the second ink flow path connecting the inkjet head and the second ink tank. The ink jet recording apparatus described.

(17th configuration)
The ink jet recording apparatus applies when the ink in the first and second ink tanks is unidirectionally or alternately transferred via a third ink flow path communicating with the first and second ink tanks. The pressure difference P10 = P8−P9 (P8> P9) between the ink pressure P8 or P9 of the first ink tank and the ink pressure P9 or P8 of the second ink tank is the first ink flow path, the second ink. The first and second inks at the time of ink pressure feeding from the first ink tank to the second ink tank or the ink pressure feeding from the second ink tank to the first ink tank via the flow path and the ink jet head 16. The ink jet recording apparatus according to the fourteenth and fifteenth configurations, wherein the ink pressure difference is greater than a tank ink pressure difference P11.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  According to the present invention, it is possible to effectively prevent the precipitation of solid components contained in the liquid, so that the concentration of the liquid is always kept constant, and the clogging in the apparatus is prevented. It can be applied to device manufacturing with high accuracy.

1 is a schematic cross-sectional view showing a first embodiment of an ink jet recording apparatus according to the present invention. It is a schematic sectional drawing which shows 2nd Embodiment of the inkjet recording device which concerns on this invention. It is a schematic sectional drawing which shows 3rd Embodiment of the inkjet recording device which concerns on this invention. It is a schematic sectional drawing which shows 4th Embodiment of the inkjet recording device which concerns on this invention.

Explanation of symbols

10 First ink tank (first liquid tank)
13 First pressure adjusting pump (pressure control means)
15 First ink supply channel (first channel)
16 First two-way valve (valve)
17 Second two-way valve (valve)
20 Second ink tank (second liquid tank)
23 Second pressure adjusting pump (pressure control means)
25 Second ink supply channel (second channel)
26 Third two-way valve (valve)
27 Fourth two-way valve (valve)
30 Inkjet head (head)
36 Nozzle hole 40 Ink stirring channel (third channel)
41 Two-way solenoid valve (valve)

Claims (13)

A first liquid tank to which a first pressure is applied;
A second liquid tank to which a second pressure different from the first pressure is applied;
A flow path connecting the first liquid tank and the second liquid tank so that the liquid can be transferred;
A head coupled to a flow path between the first liquid tank and the second liquid tank so that liquid can be exchanged;
The first and second liquids are used to reciprocate the liquid between the first and second liquid tanks via the flow path and to always apply a constant negative pressure to the liquid inside the head. And a pressure control means for controlling the pressure applied to the tank.   The pressure control means reverses the liquid transfer direction before all of the liquid in one of the first and second liquid tanks is transferred into the other liquid tank. The recording apparatus according to claim 1, wherein a pressure applied to the first and second liquid tanks is controlled.   The pressure control means is applied to the first liquid tank before all of the liquid in one of the first and second liquid tanks is transferred into the other liquid tank. The pressure is changed from the first pressure to the second pressure, and the pressure applied to the second liquid tank is changed from the second pressure to the first pressure. The recording apparatus according to claim 1.   The first resistance in the flow path between the first liquid tank and the head and the second resistance in the flow path between the second liquid tank and the head are substantially the same. The recording apparatus according to claim 1, wherein: When the first pressure is P1, the second pressure is P2, and the pressure applied to the liquid in the head is P, the pressure control means satisfies the relationship P1>P> P2. The first resistance R1 in the flow path between the liquid tank and the head and the second resistance R2 in the flow path between the second liquid tank and the head are (1 )
(P1-P) / R1 = (P-P2) / R2 (1)
In addition, before all of the liquid in the first liquid tank is transferred into the second liquid tank, a third pressure P3 is applied to the first liquid tank, and the second liquid tank is applied to the second liquid tank. When the fourth pressure P4 is applied and the relationship of P4>P> P3 is satisfied, the first resistor R1 and the second resistor R2 satisfy the following expression (2), the liquid tank, The recording apparatus according to claim 1, wherein the pressure applied to the liquid in the head is controlled.
(P-P3) / R1 = (P4-P) / R2 (2)   2. The recording according to claim 1, wherein the pressure control means holds the pressure applied to the liquid in the head when discharging the liquid within a range of ± 0.5 kPa with respect to a set pressure. apparatus.   In the pressure control means, the liquid flow rate per unit time of the liquid transferred through the flow path is more than twice the liquid outflow amount per unit time of the liquid flowing out of the apparatus by the ejection from the head. The recording apparatus according to claim 1, wherein the pressure applied to the liquid tank and the head is controlled.   The recording apparatus according to claim 1, wherein the liquid in the liquid tank, the flow path, and the liquid in the head do not come into contact with air except for a liquid discharge port formed in the head. The flow path includes a first flow path between the first liquid tank and the head, and a second flow path between the second liquid tank and the head,
The third flow path is further provided between the first liquid tank and the second liquid tank so that the liquid can be transferred without passing through the head. Recording device.   The recording apparatus according to claim 9, wherein each of the first, second, and third flow paths has a valve.   The flow path resistance R3 of the third flow path is smaller than the sum (R1 + R2) of the flow path resistance R1 of the first flow path and the flow path resistance R2 of the second flow path. 9. The recording apparatus according to 9. When the liquid is transferred between the first liquid tank and the second liquid tank via the third flow path, the first pressure applied to the first liquid tank and the second pressure are applied. The difference from the second pressure applied to the liquid tank is
A first pressure applied to the first liquid tank when the liquid is transferred between the first liquid tank and the second liquid tank via the first and second flow paths; The recording apparatus according to claim 9, wherein the recording apparatus is greater than a difference from a second pressure applied to the second liquid tank.   A head connected to be able to exchange liquid between a first liquid tank to which a first pressure is applied and a second liquid tank to which a second pressure different from the first pressure is applied. On the other hand, the liquid is reciprocally transferred in the flow path connecting the first and second liquid tanks, and the liquid inside the head connected to be able to exchange the liquid between the first and second liquid tanks is always present. A recording method comprising a pressure control step of controlling the pressure so as to apply a pressure to the first and second liquid tanks so that a constant negative pressure is applied.

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