JP2009143101A - Liquid supplying device and inkjet recorder equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid supplying device capable of stably jetting deaerated liquid from an inkjet head by dissolving residual air in a path in the deaerated liquid, and an inkjet recorder. <P>SOLUTION: The inkjet recorder 100 is equipped with an ink supplying device 2 supplying ink jetted from the inkjet head 1. The ink supplying device 2 is provided with an ink forming path 21 through which the ink ejected from a sealed tank 20 is fed to a deaeration module 23 and deaerated ink formed in the deaeration module 23 returns to the sealed tank 20, and an ink supplying path 122 through which the deaerated ink in the sealed tank 20 is supplied to the inkjet head 1 independently of each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid supply apparatus for stably ejecting deaerated ink from an inkjet head, and an inkjet recording apparatus including the liquid supply apparatus.

  As a method of stabilizing ink ejection in an ink jet recording apparatus, a method of removing dissolved gas in ink supplied to an ink jet head is known. An ink jet recording apparatus ejects ink from an ink jet head by driving the ink jet head. However, micro air dissolved in the ink existing in the ink jet head is generated as bubbles due to pressure fluctuations generated when the ink jet head is driven.

  In addition, when the ink supply pipe to the ink jet head is empty (initial state), if ink is supplied into the ink jet head, bubbles remain in the pipe when ink is supplied to the ink jet head. . As a result, the remaining bubbles flow into the inkjet head together with the ink. For this reason, non-ejection of ink or variation (ejection unevenness) occurs in ink ejection. As a result, a change (variation) occurs in the amount of ink landed on the substrate, and the change (variation) causes uneven stripes. That is, the substrate after ink discharge becomes a defective product.

  In view of this, the ink jet recording apparatus is configured so as to minimize the occurrence of air residue in the supply path for supplying ink to the ink jet head, or by providing a deaeration device in the supply path to remove the degassed ink. Is supplied to the inkjet head.

  In an inkjet recording apparatus including a deaeration device, for example, an inlet and an outlet of a deaeration module (a filter made of a Teflon (registered trademark) film or a polyethylene film) are connected in series to the piping serving as the supply path. Further, a vacuum pump is connected to the deaeration module in order to keep the inside of the deaeration module in a vacuum. Thereby, an ink from which air dissolved in the ink is removed (hereinafter referred to as “deaerated ink”) is produced. Then, the deaerated ink is supplied to the ink jet head through the supply path. Accordingly, it is possible to reduce bubbles generated by driving the ink jet head and to suppress non-ejection of ink that occurs when the air remaining in the pipe in the initial state dissolves in the ink.

  However, even if the deaerated ink is produced in this way, when the deaerated ink is exposed to air, the air dissolves in the ink and immediately returns to a saturated state. For this reason, how to prepare a deaerated ink with a high degree of deaeration, how to supply the ink to the inkjet head while maintaining the deaeration degree of the deaerated ink, and how to supply air in the supply path (in the pipe) The problem is whether ink can be supplied without residual ink remaining.

  Therefore, Patent Document 1 discloses an ink jet recording apparatus in which the deaerated ink deaerated by the deaerator is circulated in the ink jet during the ink ejection operation by the ink jet head.

In addition, the ink jet recording apparatus includes a dissolved oxygen meter in the ink supply path, and monitors the dissolved oxygen concentration in the ink. As a result, deaerated ink in which the amount of dissolved oxygen in the ink is kept below a certain value is supplied to the inkjet head. On the other hand, when the amount of dissolved oxygen exceeds a certain value, the ink is circulated through the deaeration device without supplying ink to the inkjet head.
JP 2000-190529 A (publication date: July 11, 2000)

  However, with the configuration of Patent Document 1, it is not possible to discharge a stable degassed liquid from the inkjet head.

  Here, in order to dissolve the air in the inkjet head in the deaerated ink and dissolve the air remaining in the piping path in the deaerated ink, an ink having a high deaeration degree is required. In order to produce such deaeration ink with a high deaeration degree, for example, the ink flow rate through the deaeration module is sent as low as possible, a deaeration module with a large capacity is used, or It is conceivable to increase the number of tubes constituting the inside of the deaeration module by increasing the length and reducing the diameter of the tubes.

  However, in Patent Document 1, since the deaeration module is connected to the inkjet head, the deaeration ink formed by the deaeration module is directly supplied to the inkjet head. For this reason, for example, if the flow rate of the ink passing through the deaeration module is lowered to produce a deaeration ink having a high deaeration degree, it takes a long time to dissolve the air remaining in the pipe. . Further, when the capacity of the deaeration module disposed in front of the ink jet head is increased, it is necessary to consider a mechanism design for mounting the deaeration module on the ink jet recording apparatus. For this reason, more space is required. Moreover, if the diameter of the tube in the deaeration module is reduced to increase the number of tubes and the tube length is increased, the pipe resistance of the ink to be supplied increases. As a result, it becomes difficult to control the risk of ink clogging and the flow rate of circulating through the inkjet head. For this reason, in order to control the flow rate by the water head difference, a mechanism for managing the liquid level height on the supply side is required. Therefore, in the configuration of Patent Document 1, stable ink ejection cannot be performed from the inkjet head.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to stably discharge the deaerated liquid from the inkjet head by dissolving the residual air in the path in the deaerated liquid. An object of the present invention is to provide a liquid supply apparatus and an ink jet recording apparatus that can perform the above-described process.

In order to solve the above problems, a liquid supply apparatus of the present invention is a liquid supply apparatus that supplies liquid discharged from an inkjet head,
A closed tank in which the liquid is stored;
Provided with a degassing part for degassing the dissolved gas in the liquid in the sealed tank,
A first path in which liquid discharged from the sealed tank is sent to the degassing unit, and the degassed liquid formed in the degassing unit returns to the sealed tank;
The second path through which the degassed liquid in the sealed tank is supplied to the inkjet head is provided independently of each other.

  The liquid supply apparatus of the present invention supplies the degassed liquid formed by the first path to the ink jet head via the second path.

  According to said structure, the 1st path | route which is a formation path | route of a deaeration liquid, and the 2nd path | route which is a supply path | route of the deaeration liquid to an inkjet head are provided mutually independently. Accordingly, the deaerated liquid can be supplied to the inkjet head and the deaerated liquid can be discharged from the inkjet head without being affected by the flow rate of the first path.

  Moreover, according to the above configuration, the deaeration liquid is not supplied from the deaeration unit to the inkjet head as in Patent Document 1, but the deaeration liquid is supplied from the sealed tank to the inkjet head. For this reason, deaerated ink can be supplied to the inkjet head at a high flow rate. Thereby, the air remaining in the second path can be reliably dissolved in the deaeration liquid in a short time. Therefore, ink non-ejection caused by air remaining in the second path can be suppressed. Therefore, the deaeration liquid can be stably discharged by the inkjet head.

  Thus, according to the liquid supply apparatus of the present invention, the deaerated liquid having a high deaeration degree (low air concentration) formed by the first path is supplied to the inkjet head by the second path. Moreover, by supplying the degassed liquid to the second path at a high flow rate, the air remaining in the second path can be dissolved in the degassed liquid supplied at a high flow rate. Accordingly, it is possible to stably discharge the degassed liquid from the inkjet head.

  In the liquid supply apparatus of the present invention, it is preferable that the deaeration liquid is supplied to the inkjet head through the second path while the deaeration liquid is formed through the first path.

  According to the above configuration, the deaeration liquid is formed by the first path even while the deaeration liquid is discharged from the inkjet head. Thereby, the formation time of a deaeration liquid can be shortened and the deaeration liquid with a high deaeration degree can always be supplied to an inkjet head.

  In the liquid supply apparatus of the present invention, the degassed liquid formed in the first path circulates in the first path, and the second path is degassed liquid that is discharged without being discharged from the inkjet head. It is preferable that a path for returning the gas to the sealed tank is further provided so that the deaerated liquid discharged from the inkjet head circulates in the second path.

  According to said structure, the deaeration liquid formed with the 1st path | route circulates like 1st path | route-> sealed tank-> 1st path | route. On the other hand, independent of this circulation, the deaerated liquid discharged without being discharged from the inkjet head circulates in the second path → the sealed tank → the second path. Thereby, the deaeration liquid which was not discharged from the inkjet head is also reused. Accordingly, it is possible to reduce the consumption of useless degassed liquid.

  In the liquid supply device of the present invention, the flow rate of the liquid or the deaerated liquid flowing in the first path may be larger than the flow rate of the deaerated liquid flowing in the second path.

  According to said structure, it is more than the flow volume of the 2nd path | route which supplies deaeration liquid rather than the flow volume of the 1st path | route which forms deaeration liquid. Thereby, the amount of the deaerated liquid supplied to the second path is smaller than the amount of the deaerated liquid formed by the first path. Therefore, it is possible to reliably supply a deaerated liquid having a high deaeration degree to the second path.

The liquid supply apparatus of the present invention includes a liquid feed pump in a path that is discharged without being discharged from the inkjet head in the second path,
It is preferable that the liquid feeding pump applies a negative pressure to the inkjet head to supply the deaerated liquid from the sealed tank to the second path.

  According to said structure, the liquid feeding pump is provided in the discharge side of the inkjet head, and a negative pressure is applied to an inkjet head. Accordingly, the deaerated ink can be supplied to the second path without destroying the meniscus of the inkjet head.

  In the liquid supply apparatus of the present invention, it is preferable that the closed tank is configured to reduce the volume of the closed tank as the liquid or degassed liquid in the closed tank decreases.

  According to the above configuration, the volume in the closed tank is changed in conjunction with the volume change of the liquid or degassed liquid in the closed tank. Thereby, it is possible to reduce the intrusion of air from the inkjet head through the second path into the sealed tank.

  Such a closed tank whose volume changes in conjunction with the volume change can be constituted by, for example, a cylinder in which the liquid is stored and a piston that discharges the liquid in the cylinder by pressing.

  According to said structure, the meniscus of an inkjet head can be controlled by controlling the pressure of a piston.

  Further, the closed tank whose volume varies in conjunction with such a volume variation can be configured as a bag. Thereby, the volume can be changed in conjunction with the volume change of the closed tank with a simple configuration.

  In the liquid supply apparatus of the present invention, the surface of the closed tank is preferably laminated with a metal film.

  According to said structure, since the surface of an airtight tank is laminated by the metal film, the penetration | invasion of the air to an airtight tank is interrupted | blocked effectively. Thereby, the deaeration liquid in an airtight tank can be maintained in a state with a high deaeration degree. That is, the oxygen concentration of the degassed liquid can be kept low.

The liquid supply apparatus of the present invention includes a sealed container for storing degassed liquid discharged without being discharged from the inkjet head in the second path,
It is preferable that the liquid feeding pump is connected to an airtight container.

  According to said structure, the airtight container which stores the deaeration liquid which was not discharged with the ink jet head is provided between the ink jet head of the 2nd path | route, and the airtight tank. In addition, a liquid feed pump is connected to the sealed container. As a result, the deaerated ink can be supplied with less pulsation than when the deaerated liquid is directly fed to the second path by the liquid feed pump. Therefore, more stable ink supply is possible.

The liquid supply apparatus of the present invention includes a pressurizing / depressurizing pump that pressurizes or depressurizes the sealed container;
A pressure sensor for detecting the pressure in the sealed container,
It is preferable that the rotation speed of the pressure increasing / decreasing pump is controlled so that the output value of the pressure sensor approximates the set pressure value of the pressure increasing / decreasing pump at which the inside of the sealed container has a predetermined pressure.

  According to the above configuration, the output of the pressure sensor is such that the output value of the pressure sensor approximates the set pressure value of the pressure increase / reduction pump at which the inside of the sealed container has a predetermined pressure. The rotation speed is controlled. Thereby, the deaerated liquid can be supplied from the sealed tank to the inkjet head at a flow rate substantially equal to the flow rate of the deaerated liquid at the set pressure value of the pressure increasing / decreasing pump.

  In addition, it is preferable that pressurization or pressure reduction control is performed on the pressure increasing / decreasing pump so that the pressure sensor always shows a constant value. Thereby, the pressure value in the sealed container is maintained constant. Thereby, the pressure in the sealed container is always maintained at a constant value. Therefore, the deaerated liquid can be sent to the inkjet head at a constant flow rate.

  The liquid supply apparatus of the present invention preferably includes an ink bag in which the deaerated liquid is stored inside the sealed container, and the sealed container and the ink bag are shut off.

  According to said structure, the deaeration liquid discharged | emitted from the inkjet head is stored in an ink bag. Accordingly, the deaerated liquid can be fed to the ink bag storing the deaerated liquid without touching the outside air.

The liquid supply apparatus of the present invention accommodates the second ink bag for storing the degassed liquid discharged from the sealed tank and the second ink bag in the path of the sealed tank and the inkjet head in the second path. And a second sealed container
The pressurizing / depressurizing pump can feed the deaerated liquid discharged from the sealed tank in the order of the second ink bag, the inkjet head, and the ink bag by controlling the sealed container and the second sealed container to a negative pressure. preferable.

  According to said structure, a pressure increase / decrease pump controls a sealed container and a 2nd sealed container to a negative pressure. As a result, the meniscus of the inkjet head can be controlled by the ink bag and the second ink bag having a smaller volume than the sealed tank.

In the liquid supply apparatus of the present invention, the second path is branched in the path between the sealed tank and the inkjet head, and the branched path is where the deaerated liquid discharged from the deaeration unit is fed to the sealed tank. Connected to the route
The second path is further branched in the path between the sealed tank and the ink bag, and is preferably connected to a path through which the liquid in the sealed tank is fed to the deaeration unit.

  According to said structure, the 2nd path | route is branched in the path | route of a sealed tank and an inkjet head, The deaerated liquid discharged | emitted from a deaeration part is sent to the sealed tank by the branched path | route. Connected to the route. That is, the branched path is a path in which the deaerated liquid formed by the deaeration unit in the first path returns to the sealed tank.

  Further, the second path further branches in the path between the sealed tank and the ink bag, and the second path is connected to a path through which the liquid in the sealed tank is fed to the deaeration unit. Has been. That is, the branched path is a path through which the liquid discharged from the sealed tank in the first path is sent to the deaeration unit.

  As described above, according to the above configuration, the first route and the second route are partially shared. As a result, the liquid in the sealed tank can be degassed only with a spout that supplies ink from the sealed tank to the second ink bag while discharging the degassed liquid with the inkjet head.

  The liquid supply apparatus of the present invention preferably includes a waste liquid tank in which a degassed liquid discharged without being discharged from the inkjet head is stored.

  According to said structure, the deaeration liquid which was not discharged from the inkjet head is stored in a waste liquid tank. Thereby, the deaeration liquid stored in the waste liquid tank can be reused.

  An ink jet recording apparatus of the present invention includes any one of the above liquid supply devices and an ink jet head.

  Since the inkjet recording apparatus of the present invention includes the liquid supply apparatus of the present invention, it is possible to stably discharge the degassed liquid from the inkjet head.

  As described above, according to the present invention, the liquid discharged from the sealed tank is sent to the degassing unit, and the degassed liquid formed in the degassing unit returns to the sealed tank, and the closed tank And a second path through which the degassed liquid is supplied to the inkjet head are provided independently of each other. Therefore, there is an effect that stable ink discharge is possible from the inkjet head.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Note that the present invention is not limited to the configurations of the following embodiments. Moreover, below, about the member which shows the same function and effect | action, the same code | symbol is attached | subjected and description is abbreviate | omitted.

[Embodiment 1]
The inkjet recording apparatus of the present invention includes a path for degassing ink in the sealed tank to form degassed ink and a path for supplying the degassed ink from the sealed tank to the inkjet head, independently of each other. Thus, the deaerated ink is fed to the inkjet head at a high flow rate.

  FIG. 1 is a plan view showing the main configuration of the ink jet recording apparatus according to the first embodiment. As shown in FIG. 1, the inkjet recording apparatus 10 includes an inkjet head 1 that ejects ink, and an ink supply device (liquid supply device) 2 a that supplies ink to the inkjet head 1. The ink jet recording apparatus 10 manufactures a color filter by, for example, discharging colored ink from the ink jet head 1 onto a substrate. That is, the ink jet recording apparatus 10 is used as a color filter manufacturing apparatus.

  The inkjet head 1 ejects the deaerated ink supplied from the ink supply device 2 onto a substrate (not shown) to be ejected. The inkjet head 1 includes an ink flow path 11 serving as a flow path for deaerated ink, and a nozzle 12 that discharges the deaerated ink supplied to the ink flow path 11. The nozzle 12 is formed with a plurality of openings, and the deaerated ink is ejected from the openings.

  The ink supply device 2 a supplies ink ejected from the inkjet head 1 to the inkjet head 1. The ink supply device 2 a includes a sealed tank 20, and the ink supplied to the inkjet head 1 is stored in the sealed tank 20. The ink supply device 2a degass at least a part of the dissolved gas in the ink stored in the sealed tank 20 to form degassed ink, and the formed degassed ink. And an ink supply path 122 (second path) for supplying the ink from the sealed tank 20 to the inkjet head 1.

  The sealed tank 20 has a sealed structure in order to shield it from the outside air. Thereby, even if the deaerated ink formed by the ink forming path 21 is held in the sealed tank 20, the deaerated ink is not exposed to the outside air. Therefore, the degree of deaeration of the deaerated ink can be maintained in the sealed tank 20. The sealed tank 20 is preferably formed of, for example, a metal that shields air from the outside, PVC (polyvinyl chloride) resin, or PE (polyethylene) resin.

  In the ink formation path 21, a deaeration module 23 (a deaeration unit) that deaerates dissolved gas in the ink discharged from the sealed tank 20 is installed. The ink formation path 21 supplies the degassing module 23, a pipe 24 for supplying the ink discharged from the sealed tank 20 to the degassing module 23, and the degassed ink discharged from the degassing module 23 to the sealed tank 20. It is formed from the piping 25 to do. Further, a liquid feed pump 26 is provided in the pipe 25 (between the deaeration module 23 and the sealed tank 20).

  Inside the deaeration module 23, a bundle of a plurality of gas permeable hollow fibers is provided. In addition, a liquid feed pump 27 is connected to the deaeration module 23. Thus, when ink is fed into the hollow fiber in the degassing module 23, the pressure in the degassing module 23 is made negative by the vacuum pump 8 from the outside of the hollow fiber, so that the ink is dissolved in the ink. The gas that is present can be removed from the ink. In the present embodiment, the deaeration module 23 is a deaeration module manufactured by Junko Co., Ltd. in which a Teflon (registered trademark) material such as PFA is used as the hollow fiber deaeration membrane constituting the hollow fiber.

  In order to efficiently deaerate ink with the deaeration module 23, it is desirable to increase the degree of vacuum in the deaeration module 23. In the present embodiment, a diaphragm pump having a compact size and a performance of −94, 5 kPa (DAP-6D (93 (W) × 163 (L) × 100.6 (H ))It was used.

  In the ink formation path 21, the flow rate of the ink circulating in the ink formation path 21 is adjusted by controlling the rotation speed of the motor of the liquid feed pump 26. By adjusting the ink flow rate in this way, the degree of deaeration of the deaerated ink formed in the ink formation path 21 can also be adjusted. As the liquid feeding pump 27, for example, a tube pump can be used. In this embodiment, a tube pump of Wilco WPX-149 (W) × 46 (L) × 100 (H)) is used as the liquid feed pump 26.

  In the ink formation path 21, the ink discharged from the sealed tank 20 passes through the pipe 24 and is supplied to the deaeration module 23. From the supplied ink, the gas remaining in the ink is degassed by the degassing module 23 to form degassed ink. The formed deaeration ink is discharged from the deaeration module 23, passes through the pipe 25, and returns to the sealed tank 20 again. In this way, the ink in the sealed tank 20 circulates in the ink formation path 21 as in the sealed tank 20 → the deaeration module 23 → the sealed tank, and so on, and the process of forming the deaerated ink is repeated. As a result, the entire ink in the sealed tank 20 is replaced with deaerated ink.

  The pipes 24 and 25 connected to the sealed tank 20 and the deaeration module are preferably made of high air barrier tubes such as metal SUS pipes and PVC pipes. Further, the pipes 24 and 25 are connected to the sealed tank 20 and the deaeration module 23 by using a SUS joint made by Swagelok Co., Ltd. (not shown) to prevent gas from entering from the outside as much as possible. preferable.

  In the initial stage where ink is supplied from the sealed tank 20 to the pipes 24 and 25, air remains in the pipes 24 and 25. For this reason, when this air residue is considered, it is preferable that the diameters of the pipes 24 and 25 are small. However, when the diameters of the pipes 24 and 25 are small and the length is long, the flow resistance of the ink flowing through the pipes 24 and 25 is increased. For this reason, the performance of the liquid feed pump 26 for circulating the ink is limited. Therefore, in this embodiment, the pipes 24 and 25 having an outer diameter of 4 mm and an inner diameter of 2 mm are used, and the lengths of the pipes 24 and 25 are shortened as much as possible in consideration of the efficiency of deaeration and the arrangement of members.

  On the other hand, the ink supply path 122 is a path for supplying the deaerated ink formed by the ink formation path 21 from the sealed tank 20 to the inkjet head 1 positioned below the sealed tank 20. The ink supply path 122 includes a pipe 28 that supplies the deaerated ink discharged from the sealed tank 20 to the inkjet head 1, a waste liquid tank 90 that stores deaerated ink that has not been ejected by the inkjet head 1, and an inkjet head 1 that ejects the ink. It is formed from a pipe 39 that supplies degassing ink that has not been supplied to the waste liquid tank 90. Further, a liquid feed pump 30 is provided in the pipe 39 (between the inkjet head 1 and the waste liquid tank 90). The deaerated ink is supplied from the sealed tank 20 to the ink supply path 122 so that the deaerated ink always flows through the inkjet head 1 (ink flow path 11).

  The pipes 28 and 39 can be the same as the pipes 24 and 25 of the ink forming path 21. In this embodiment, SUS pipes having an outer diameter of 4 mm and an inner diameter of 2 mm are used.

  In the ink supply path 122, the flow rate of the ink circulating in the ink supply path 122 is adjusted by controlling the rotation speed of the motor of the liquid feed pump 30. For example, a tube pump can be used as the liquid feeding pump 30 in the same manner as the liquid feeding pump 27.

  In the ink supply path 122, the deaerated ink discharged from the sealed tank 20 passes through the pipe 28 and is supplied to the inkjet head 1 (ink flow path 11). The supplied ink is ejected from the nozzle 12. On the other hand, the deaerated ink that has not been ejected from the nozzle 12 is discharged from the inkjet head 1, passes through the pipe 39, and is sent to the waste liquid tank 90.

  Specifically, the ink flow path 11 of the inkjet head 1 has a supply port through which the deaerated ink is supplied from the sealed tank 20 and a discharge port through which the deaerated ink that has not been discharged from the nozzle 12 is discharged. (Not shown). Further, a connector (not shown) is provided at each of the supply port and the discharge port, and pipes 28 and 39 are connected to the connector. Thereby, the deaerated ink can be sent from the sealed tank 20 to the inkjet head 1.

  In the vicinity of the ink flow path 11 of the inkjet head 1, a nozzle 12 having a plurality of openings is provided. For this reason, the deaerated ink supplied to the inkjet head 1 is discharged from the opening of each nozzle 12 by the drive of the inkjet head 1. The deaerated ink that has not been discharged is discharged from the discharge port of the ink flow path 11 and is sent to the waste liquid tank 90 through the pipe 39. The deaerated ink that has not been ejected from the inkjet head 1 can be sent to the waste liquid tank 90 by the liquid feed pump 30 in the same manner as described above.

  The degassed liquid stored in the waste liquid tank 90 is usually discarded as waste liquid as it is. However, if the waste liquid tank 90 is a sealed container, the degassed liquid stored in the waste liquid tank 90 can be stored in a degassed state. For this reason, reuse becomes possible.

  In the present embodiment, a WPX-149 (W) × 46 (L) × 100 (H)) tube pump manufactured by Wilco is used as the liquid feeding pump 30 in the same manner as the liquid feeding pump 26. Since this tube pump is small in size, the peripheral design of the inkjet head 1 does not affect the ink supply path 122, the interference problem, and the like. Therefore, an ink supply system in the inkjet recording apparatus 10 can be easily constructed. The sizes of the liquid feed pumps 26 and 30 are not limited to this, and may be set in consideration of the size of the ink jet recording apparatus 10 and the space with other members.

  If tube pumps are used as the liquid feed pumps 26 and 30, the flow rate of the deaerated ink is in the range of several cc to several tens of cc by changing the gear ratio of the motor provided in the tube pump and the voltage setting of the driver. Can be delivered accurately.

  Further, the liquid feed pump 30 is preferably disposed in the middle of the pipe 39 through which the deaerated ink from the inkjet head 1 is discharged. In other words, the liquid feed pump 30 is preferably disposed in a path for feeding deaerated ink that has not been ejected from the nozzles 12 to the waste liquid tank 90. When the liquid feed pump 30 is provided in the middle of the pipe 28 to which the deaerated ink is supplied from the sealed tank 20 to the inkjet head 1, the deaerated ink is fed to the inkjet head 1 by pressurization. For this reason, the meniscus of the plurality of openings formed in the nozzle 12 of the inkjet head 1 is destroyed by the pressurization, and the deaerated ink may flow from the opening to the surface of the nozzle 12. On the other hand, when the liquid feeding pump 30 is provided in the middle of the pipe 39 (on the side where the deaerated ink is discharged), the deaerated ink is fed to the inkjet head 1 at a negative pressure. For this reason, the deaerated ink can be fed to the ink flow path 11 in the inkjet head 1 without destroying the meniscus as in the case of pressurization.

  As described above, the ink jet recording apparatus 100 is provided with the two paths of the ink forming path 21 and the ink supply path 122 independently of each other. The ink forming path 21 and the ink supply path 122 are not related to each other and allow the deaerated ink to flow. That is, the deaerated ink can always be formed in the ink forming path 21, while the deaerated ink can be supplied to the inkjet head 1 through the ink supply path 122. Therefore, the flow rate of the deaerated ink in the ink formation path 21 and the flow rate of the deaerated ink in the ink supply path 122 can be controlled independently. Thereby, the deaerated ink can be supplied to the inkjet head 1 and the deaerated ink can be discharged from the nozzles 12 without being affected by the flow rate of the ink forming path 21.

  Furthermore, the ink supply device 2a according to the present embodiment supplies the deaerated ink from the sealed tank 20 to the inkjet head 1 instead of supplying the deaerated ink from the deaeration module 23 to the inkjet head 1 as in the prior art. For this reason, deaerated ink can be supplied to the inkjet head 1 at a high flow rate. Thereby, the air remaining in the ink supply path 122 (particularly the pipes 28 and 39) can be reliably dissolved in the deaerated ink in a short time. Therefore, ink non-ejection caused by air remaining in the ink supply path 122 can be suppressed.

[Embodiment 2]
In the configuration of the first embodiment, the deaerated ink that has not been ejected from the inkjet head 1 is sent to the waste liquid tank 90 and is usually discarded. The amount of deaerated ink ejected from the inkjet head 1 is extremely smaller than the amount of deaerated ink supplied to the ink flow path 11 of the inkjet head 1. For this reason, useless ink consumption increases.

  Therefore, in the second embodiment, a configuration for effectively using deaerated ink discharged from the inkjet head 1 without waste will be described.

  FIG. 2 is a plan view showing the main configuration of the ink jet recording apparatus according to the second embodiment. As shown in FIG. 2, the ink jet recording apparatus 100 includes an ink jet head 1 that ejects ink, and an ink supply device (liquid supply device) 2 that supplies ink to the ink jet head 1. The ink jet recording apparatus 100 of the second embodiment has substantially the same configuration as the ink jet recording apparatus 10 of the first embodiment. However, the configuration of the inkjet supply device 2 is different from the inkjet supply device 2a of the first embodiment.

  The ink supply device 2 supplies ink ejected from the inkjet head 1 to the inkjet head 1. The ink supply device 2 includes a sealed tank 20, and the ink supplied to the inkjet head 1 is stored in the sealed tank 20. The ink supply device 2 degass at least a part of the dissolved gas in the ink stored in the sealed tank 20 to form degassed ink, and the formed degassed ink. And an ink supply path 22 (second path) for supplying the ink from the sealed tank 20 to the inkjet head 1.

  In the inkjet recording apparatus 100, the deaerated ink circulates through the ink supply path 22. This ink supply path 22 is greatly different from the ink supply path 122 of Embodiment 1 in which the deaerated ink does not circulate.

  Specifically, the ink supply path 22 is a path for supplying the deaerated ink formed by the ink formation path 21 from the sealed tank 20 to the inkjet head 1 positioned below the sealed tank 20. The ink supply path 22 is formed by a pipe 28 that supplies the deaerated ink discharged from the sealed tank 20 to the inkjet head 1 and a pipe 29 that supplies the deaerated ink that has not been ejected by the inkjet head 1 to the sealed tank 20. Has been. A liquid feed pump 30 is provided in the pipe 29 (between the inkjet head 1 and the sealed tank 20). The deaerated ink is supplied from the sealed tank 20 to the ink supply path 22 so that the deaerated ink always flows through the inkjet head 1 (ink flow path 11).

  The pipe 29 is a path for returning the deaerated ink discharged without being ejected from the inkjet head 1 to the sealed tank 20. The pipe 29 can be the same as the pipes 24 and 25 of the ink forming path 21. In this embodiment, a SUS pipe having an outer diameter of 4 mm and an inner diameter of 2 mm is used.

  Here, the amount of deaerated ink ejected from the nozzles 12 of the inkjet head 1 is extremely smaller than the amount of deaerated ink supplied to the ink flow path 11 of the inkjet head 1. Therefore, in this embodiment, by providing the pipe 29, the deaerated ink that has not been ejected from the nozzle 12 is returned from the inkjet head 1 to the sealed tank 20. That is, the deaerated ink discharged from the inkjet head 1 circulates through the ink supply path 22. Thereby, the deaerated ink can be effectively used without waste.

  In the ink supply path 22, the flow rate of the ink circulating in the ink supply path 22 is adjusted by controlling the rotation speed of the motor of the liquid feed pump 30. For example, a tube pump can be used as the liquid feeding pump 30 in the same manner as the liquid feeding pump 27.

  In the ink supply path 22, the deaerated ink discharged from the sealed tank 20 passes through the pipe 28 and is supplied to the inkjet head 1 (ink flow path 11). The supplied ink is ejected from the nozzle 12. On the other hand, the deaerated ink that has not been ejected from the nozzle 12 is discharged from the inkjet head 1, passes through the pipe 29, and returns to the sealed tank 20 again. In this way, the deaerated ink that has been supplied to the inkjet head 1 and has not been discharged from the nozzle 12 circulates in the ink supply path 22 as in the sealed tank 20 → the inkjet head 1 → the sealed tank 20. As a result, the deaerated ink that has not been ejected from the inkjet head 1 is also reused. Accordingly, it is possible to reduce the amount of wasted degassing ink consumed.

  Specifically, the ink flow path 11 of the inkjet head 1 has a supply port through which the deaerated ink is supplied from the sealed tank 20 and a discharge port through which the deaerated ink that has not been discharged from the nozzle 12 is discharged. (Not shown). Further, a connector (not shown) is provided at each of the supply port and the discharge port, and pipes 29 and 30 are connected to the connector. Thereby, the deaerated ink can be sent from the sealed tank 20 to the inkjet head 1.

  In the vicinity of the ink flow path 11 of the inkjet head 1, a nozzle 12 having a plurality of openings is provided. For this reason, the deaerated ink supplied to the inkjet head 1 is discharged from the opening of each nozzle 12 by the drive of the inkjet head 1. The deaerated ink that has not been discharged is discharged from the discharge port of the ink flow path 11 and returns to the sealed tank 20 via the pipe 29 again. The deaerated ink that has not been ejected from the inkjet head 1 can be returned to the sealed tank 20 by the liquid feed pump 30 in the same manner as described above.

  The liquid feed pump 30 is preferably disposed in the middle of the pipe 29 through which the deaerated ink from the inkjet head 1 is discharged. That is, the liquid feed pump 30 is preferably disposed in a path for returning the deaerated ink that has not been ejected from the nozzles 12 to the sealed tank 20. When the liquid feed pump 30 is provided in the middle of the pipe 28 to which the deaerated ink is supplied from the sealed tank 20 to the inkjet head 1, the deaerated ink is fed to the inkjet head 1 by pressurization. For this reason, the meniscus of the plurality of openings formed in the nozzle 12 of the inkjet head 1 is destroyed by the pressurization, and the deaerated ink may flow from the opening to the surface of the nozzle 12. On the other hand, when the liquid feeding pump 30 is provided in the middle of the pipe 29 (on the side where the deaerated ink is discharged), the deaerated ink is fed to the inkjet head 1 at a negative pressure. For this reason, the deaerated ink can be fed to the ink flow path 11 in the inkjet head 1 without destroying the meniscus as in the case of pressurization.

  As described above, the ink jet recording apparatus 100 is also provided with the two ink forming paths 21 and the ink supply paths 22 independently of each other, as in the ink jet recording apparatus 10 of the first embodiment. Thereby, the deaerated ink can be supplied to the inkjet head 1 and the deaerated ink can be discharged from the nozzles 12 without being affected by the flow rate of the ink forming path 21. Further, non-ejection of ink caused by air remaining in the ink supply path 22 can be suppressed.

  In addition, the ink jet recording apparatus 100 circulates the deaerated ink formed in the ink forming path 21 in the order of the ink forming path 21 → the sealed tank 20 → the ink forming path 21. On the other hand, independent of this circulation, the deaerated ink discharged without being ejected from the inkjet head 1 circulates in the order of the ink supply path 22 → the sealed tank 20 → the ink supply path 22. As a result, the deaerated ink that has not been ejected from the inkjet head 1 is also reused. Accordingly, it is possible to reduce the amount of wasted degassing ink consumed.

  Here, the result of confirming the effect of the ink jet recording apparatus 100 (ink supply apparatus 2) of the present embodiment will be described. FIG. 3 is a diagram showing the sealed tank 20 of FIG. 2, and FIG. 4 is a diagram showing the configuration of the apparatus whose effect has been confirmed.

  As shown in FIG. 3, the sealed tank 20 has a configuration like a syringe. That is. The sealed tank 20 includes a cylinder 31 and a piston 32. The cylinder 31 is filled with ink. A connection port for supplying deaerated ink to the ink formation path 21 and the ink supply path 22 is formed at the bottom of the cylinder 31. Thereby, the deaerated ink in the sealed tank 20 is completely shielded from the outside air.

  Further, the ink in the sealed tank 20 decreases as it is ejected from the nozzles 12 of the inkjet head 1. At this time, there is a risk that air may enter the sealed tank 20 from the nozzle 12 through the ink supply path 22. This risk increases as the drive time of the inkjet head 1 increases. For this reason, the sealed tank 20 is configured to reduce the volume in the sealed tank 20 following the decrease in the volume of the ink. That is, the sealed tank 20 in FIG. 3 varies the volume in the sealed tank 20 in conjunction with the volume variation of the ink inside.

  Specifically, a load cell 33 for moving the piston 32 up and down is connected to the piston 32. The load cell 33 is connected to an electric slider 34 disposed on the side of the sealed tank 20, and thereby the position of the load cell 33 is controlled. The closed tank 20 varies in volume by the vertical movement of the piston 32.

  Here, the load cell 33 is the inkjet head 1 applied when the distance (H) from the liquid level of the ink in the sealed tank 20 (cylinder 31) to the tip of the nozzle 12 of the inkjet head 1 and the density (ρ) of the ink. The piston 32 is held so as to be the sum of the force of the water head difference (F; F = ρgH) and the own weight of the piston 32. Then, the load cell 33 is lowered and the load cell 33 is lowered in accordance with the amount of ink discharged from the nozzle 12 (the amount of ink reduced in the sealed tank 20). As a result, the deaerated ink can be fed to the inkjet head 1 without destroying the meniscus of the nozzle 12.

  Note that the ink ejection amount (the amount of ink decrease in the sealed tank 20) can be detected by determining the volume from the graduations carved in the cylinder 31. Based on this detection result, the amount of movement of the load cell 33 is controlled.

  The effect of the ink supply device 2 provided with such a sealed tank 20 was confirmed by arranging oxygen concentration meters 35 and 36 in the ink formation path 21 and the ink supply path 22 as shown in FIG. The oxygen concentration meter 35 is disposed in the piping 24 immediately after the ink is discharged from the sealed tank 20, and the oxygen concentration meter 36 is disposed in the piping 29 from which the ink is discharged from the inkjet head 1. Here, water-soluble ink is fed from the sealed tank 20, and water-soluble inks flowing through the pipes 24 and 29 using oxygen concentration meters manufactured by Hack Ultra Analytics Japan, Inc. as the oxygen concentration meters 35 and 36 are used. The oxygen concentration of the ink was measured. Then, the measured deaeration level was confirmed. The pipes 24 and 29 and the oximeters 35 and 36 are connected by an adapter (not shown).

  5 and 6 are graphs showing the results of measuring the oxygen concentration in the ink in the ink forming path 21 using the oxygen concentration meter 35 as shown in FIG. FIG. 5 shows the results when the ink flow rate circulating through the ink formation path 21 is 5 cc / min. FIG. 6 shows the results when the ink flow rate circulating through the ink formation path 21 is 5 cc / min.

  As shown in FIG. 5, when the ink flow rate was 5 cc / min, the oxygen concentration of the ink fell below 1 ppm in about 60 minutes. On the other hand, as shown in FIG. 6, when the ink flow rate was 20 cc / min, the oxygen concentration of the ink was saturated at 2.5 ppm in about 30 minutes. From these results, it was confirmed that the smaller the ink flow rate, the lower the oxygen concentration of the ink, whereas the time until the saturation concentration was reached was conversely increased.

  Next, 800 cc of deaerated ink that was deaerated to an oxygen concentration of about 1 ppm was fed from the sealed tank 20 to the inkjet head 1. Then, by measuring the oxygen concentration in the ink discharged from the ink jet head 1, the change in the amount of air remaining in the ink jet head 1 (air reduction amount) was confirmed. The ink flow rate was 1 cc / min and 10 cc / min. Moreover, the inkjet head 1 used what was formed with PC (polycarbonate) resin which has transparency. Then, the size of air trapped by the ink flowing through the ink flow path 11 and inside the ink jet head 1 (in the ink flow path 11) was visually confirmed. FIG. 7 is a graph showing the results of measuring the oxygen concentration in the ink using the oxygen concentration meter 36 as shown in FIG.

  The remaining air amount in FIG. 7 was calculated as follows. That is, pipes made of a resin having transparency such as Teflon (registered trademark) are connected to the pipes 24 and 29 in FIG. Then, the air remaining in the transparent pipe was calculated with vertical and horizontal elliptic sphere volumes with a ruler, and the remaining air amount was simply calculated from the change with time of the volume.

  As shown in FIG. 7, it is confirmed that the larger the flow rate of the deaerated ink supplied to the inkjet head 1, the shorter the time for dissolving the air remaining in the ink flow path 11 in the inkjet head 1 can be. It was. The cause of this is that, first, the deaerated ink is fed at a high flow rate, whereby the shearing force of the deaerated ink applied to the pipe 28 and the ink flow path 11 of the ink supply path 22 is increased. As a result, it is considered that the replacement ratio between the old ink remaining in the ink supply path 22 and the newly supplied deaerated ink is increased.

  As described above, the ink jet recording apparatus 100 of this embodiment includes the ink supply device 2. In addition, the ink supply device 2 is independently provided with an ink formation path 21 for forming deaerated ink and an ink supply path 22 for supplying the deaerated ink from the sealed tank 20 to the inkjet head 1. That is, the ink formation path 21 and the ink supply path 22 are separate paths. Accordingly, the deaerated ink can be supplied from the ink supply path 22 to the inkjet head 1 at a high flow rate while the ink in the sealed tank 20 is deaerated by the ink forming path 21. As a result, the air remaining in the ink supply path 22, particularly in the ink flow path 11 of the inkjet head 1, can be dissolved in the deaerated ink in a short time. Accordingly, it is possible to suppress ink non-ejection caused by air remaining in the ink supply path 22.

[Embodiment 3]
In the third embodiment, another configuration example of the sealed tank 20 of the second embodiment will be described. In FIG. 3, the sealed tank 20 is composed of a cylinder 31 and a piston 32. However, as shown in FIG. 8, a bag-like sealed tank 20a may be used.

  The sealed tank 20a in FIG. 8 is one in which the end of a resin film such as PE (polyethylene) is processed into a bag shape by thermocompression bonding. Furthermore, the surface (resin film surface) of the sealed tank 20 a is laminated with a metal film such as the aluminum film 41. Further, a spout 42 is provided so that no gap is generated between the resin film and the aluminum film 41. The spout 42 is for supplying and circulating ink from the sealed tank 20a to the ink forming path 21 and the ink supply path 22. That is, the spout 42 allows ink in the sealed tank 20 a to travel back and forth between the ink formation path 21 and the ink supply path 22. The spout 42 is a polyethylene part, and is crimped to the sealed tank 20a using a thermocompression jig (not shown).

  The spout 42 is connected to a manifold 43 outside the sealed tank 20a. Further, the manifold 43 is connected to the joint 44. Then, the ink formation path 21 and the ink supply path 22 are connected to the joint 124. As a result, the ink in the sealed tank 20a is supplied to the ink formation path 21 and the ink supply path 22, and circulates through each path. Further, an O-ring 45 is interposed between the spout 42 and the manifold 43 to prevent ink leakage.

  Similar to the sealed tank 20 of FIG. 3, such a sealed tank 20 a is configured to reduce the volume in the sealed tank 20 a following the decrease in the volume of the ink. Specifically, when the amount of ink inside decreases, the bag-like sealed tank 20a is contracted. Thereby, it is possible to suppress the intrusion of air from the nozzle 12 through the ink supply path 22 into the sealed tank 20a.

When the sealed tank 20a is contracted in this manner, the sealed tank 20a is preferably made of a flexible material with low malleability, and in addition to this, the air-permeable tank 20a is maintained to maintain the degree of deaeration of the deaerated ink. More preferably, it is made of a low material. For example, the closed tank 20a is preferably made of a material of 1.0 m ³ / (m ² · 24 h · atm) or less. For example, when the sealed tank 20a is composed of a PE film and a high-strength and durable PE film obtained by laminating an aluminum foil or an aluminum vapor-deposited film (aluminum film 41) excellent in air shielding properties, a lightweight and flexible sealed tank 20a is formed. It becomes. As such a high-strength and durable PE film, for example, an aluminum laminate film used for a silicon wafer case packaging gadget bag can be used. The sealed tank 20a can be manufactured by thermocompressing the end of such a PE film at about 140 ° C. into a bag shape.

  On the other hand, when the sealed tank 20a is disposed above the inkjet head 1 in a state where ink is put in the sealed tank 20a, the discharge of the nozzle 12 is caused by the water head difference between the discharge surface of the nozzle 12 in the inkjet head 1 and the sealed tank 20a. Pressure is applied to the surface (opening). At the same time, since the sealed tank 20a is made of a flexible material, atmospheric pressure is applied to the ink. As a result, the meniscus of the plurality of openings formed in the nozzle 12 of the inkjet head 1 is destroyed by the pressure, and the deaerated ink may flow from the opening to the surface of the nozzle 12.

  Therefore, the sealed tank 20a is preferably disposed at a position lower than the ejection surface of the nozzle 12 of the inkjet head 1. Accordingly, the deaerated ink can be supplied to the ink flow path 11 in the inkjet head 1 without destroying the meniscus of the nozzle 12 by atmospheric pressure.

  Next, in the following fourth to eighth embodiments, ink jet recording apparatuses 101 to 105 that can control the amount of deaerated ink supplied to the ink jet head 1 (ink circulation flow rate) will be described with reference to FIGS. To do.

[Embodiment 4]
FIG. 9 is a plan view showing the main configuration of the inkjet recording apparatus 101 according to the fourth embodiment. The ink jet recording apparatus 101 of FIG. 9 is different from the ink jet recording apparatus 100 of FIGS. 2 and 3 in an ink supply path 22a.

  As shown in FIG. 9, the ink jet recording apparatus 101 includes a sealed container 51 between the ink jet head 1 and the liquid feed pump 30 in the ink supply path 22a (the discharge side of the ink jet head 1). The sealed container 51 stores ink discharged without being ejected from the inkjet head 1.

  A liquid level sensor 52 is installed on each of the upper and lower portions of the sealed container 51 so that the amount of ink in the sealed container 51 is detected.

  Also connected to the sealed container 51 are a vacuum pump 53 for reducing the pressure in the sealed container 51 (negative pressure) and an air release valve 54 for maintaining or opening the reduced pressure in the sealed container 51 by opening and closing. ing.

  The ink discharge side of the inkjet head 1 and the bottom of the sealed container 51 are connected by a pipe 29a. A two-way valve 55 is provided in the middle of the pipe 29a. By opening and closing the two-way valve 55, the ink flow path from the inkjet head 1 to the sealed container 51 is opened or blocked.

  On the other hand, the sealed container 51 and the sealed tank 20 are connected by a pipe 29b. A liquid feed pump 30 is provided in the middle of the pipe 29 b to feed the ink in the sealed container 51 to the sealed tank 20.

  In such an ink supply path 22a, when the liquid feed pump 30 and the vacuum pump 53 are not driven, the atmospheric pressure is not applied to the ink in the sealed tank 20 that is the supply source of the deaerated ink. For this reason, the ink does not flow into the ink supply path 22. Therefore, when the atmosphere release valve 54 is closed and the two-way valve 55 is opened and the inside of the sealed container 51 is made negative by the vacuum pump 53, the ink in the sealed tank 20 is sucked into the sealed container 51. As a result, ink can be supplied to the inkjet head 1.

  In addition, about the setting value of the negative pressure in the airtight container 51 by the vacuum pump 53, the piping 28 from the airtight tank 20 to the inkjet head 1 connected, the ink flow path 11 (not shown) in the inkjet head 1, and What is necessary is just to calculate the flow-path resistance of the piping 29a connected from the inkjet head 1 to the airtight container 51, and to set it to the pressure beyond it. If suction is performed at the pressure set as described above, the deaerated ink flows from the sealed tank 20 in the order of the pipe 28, the inkjet head 1, the pipe 29a, and the sealed container 51.

  In order to return the ink stored in the sealed container 51 to the sealed tank 20 via the pipe 29b, first, the vacuum pump 53 is stopped, the atmosphere release valve 54 is opened, and the inside of the sealed container 51 is opened to the atmosphere. Open. In this state, the ink in the sealed container 51 is fed to the sealed tank 20 by driving the liquid feeding pump 30.

  Thus, in the present embodiment, the airtight container 51 that can store the ink discharged from the inkjet head 1 is provided in the ink supply path 22a. Thereby, the sealed container 51 functions as a buffer. As a result, it is possible to supply ink to the ink supply path 22a in a stable state with less pulsation than when the liquid supply pump 30 supplies liquid without providing the sealed container 51. That is, the sealed container 51 plays the same role as the liquid feed pump 30 in the ink jet recording apparatus 100 of FIG. 2 and supplies ink in a more stable state.

  As shown in FIG. 9, in order to make the inside of the sealed container 51 sealed, the sealed container 51 is composed of, for example, a box (container) that can store ink (not shown) and a lid that closes the box (container). do it. Then, a lid is arranged on the upper side of the box, and the box and the lid are fastened through an O-ring. Thereby, the intrusion of air into the sealed container 51 can be prevented. Further, as described above, the ink in the sealed container 51 may leak to the vacuum pump 53. Therefore, when the vacuum pump 53 is connected to the lid fixed to the box, it is preferable to use a pipe joint made by Swagelok (not shown) or the like as described above. Further, it is desirable that this pipe joint is arranged at the uppermost part in the sealed container 51 so that ink does not enter the vacuum pump 53 side. In addition, what is necessary is just to weld a box and a lid | cover, when the lid | cover of the airtight container 51 cannot be opened permanently.

  In this embodiment, a liquid level sensor 52 is provided on the upper and lower sides of the sealed container 51 in order to grasp the amount of ink in the sealed container 51. As a result, the ink in the sealed container 51 becomes full, and the ink can be prevented from entering the vacuum pump 53.

  The liquid level sensor 52 may be installed either outside or inside the sealed container 51. The liquid level sensor 52 includes, for example, a light emitting unit that emits laser light and a light receiving unit that receives laser light from the light emitting unit. When the liquid level sensor 52 is installed outside the sealed container 51 as described above, it is preferable that the sealed container 51 is made of a light transmissive material such as glass so that the laser emission of the liquid level sensor 52 can be detected on the light receiving side. . On the other hand, when the liquid level sensor 52 is installed inside the sealed container 51, a float switch can be applied as the liquid level sensor 52 instead of a sensor using laser light. When a float switch is used, an appropriate one may be selected in consideration of the ink resistance of the float switch.

  When such a liquid level sensor 52 is provided, if the liquid level of the ink reaches the position of the liquid level sensor 52 installed on the upper part of the sealed container 51, the liquid level sensor 52 detects it. Then, the liquid feed pump 30 operates so that the ink in the sealed container 51 returns to the sealed tank 20 through the pipe 29b. Here, if the liquid feed pump 30 is operated without opening the air release valve 54, the ink in the ink flow path 11 in the ink jet head 1 may flow at a high flow rate equivalent to the flow rate of the liquid feed pump 30. For this reason, when driving the liquid feed pump 30, it is preferable to stop the vacuum pump 53 and open the air release valve 54 provided on the lid (upper part) of the sealed container 51. Thereby, since the liquid feed pump 30 operates in a state where the airtight container 51 is open to the atmosphere, the ink in the ink flow path 11 in the inkjet head 1 does not flow at a high flow rate.

  Further, when the inside of the sealed container 51 is opened to the atmosphere, force is applied to the nozzles 12 of the inkjet head 1 due to a water head difference from the ink level in the sealed container 51. For this reason, ink may be ejected from the nozzles 12 by the force. Therefore, it is preferable to close the two-way valve 55 when the sealed container 51 is opened to the atmosphere. Thereby, it can prevent that the force by the head difference is applied to the nozzle 12, and the unnecessary discharge from the nozzle 12 can be avoided.

  Further, in the present embodiment, the liquid level of the ink in the sealed container 51 is lowered by the operation of the liquid feed pump 30, and the liquid level of the ink in the sealed container 51 causes the liquid level sensor 52 on the lower side of the sealed container 51. If it falls below, the said liquid feeding pump 30 will stop. At the same time, the air release valve 54 is closed, the two-way valve 55 provided on the pipe 29a through which the ink is discharged from the ink jet head 1 is opened, and the vacuum pump 53 is driven, thereby sealing again. Ink is supplied from the tank 20 to the inkjet head 1.

[Embodiment 5]
FIG. 10 is a plan view showing the main configuration of the inkjet recording apparatus 102 according to the fifth embodiment. The ink jet recording apparatus 102 in FIG. 10 has substantially the same configuration as the ink jet recording apparatus 101 in the fourth embodiment shown in FIG. The ink jet recording apparatus 102 in FIG. 10 is different from the ink jet recording apparatus 101 in FIG. 9 in an ink supply path 22b.

  As shown in FIG. 10, in the ink jet recording apparatus 102, a pressure sensor 56 and a pressure increasing / decreasing pump 57 are connected to a sealed container 51 provided in the ink supply path 22b. On the other hand, the ink jet recording apparatus 102 does not include the vacuum pump 53, the air release valve 54, and the two-way valve 55 in the ink jet recording apparatus 101 of FIG. The ink jet recording apparatus 102 is different from the ink jet recording apparatus 101 in these points.

  The pressure sensor 56 detects the pressure in the sealed container 51. For example, a pressure sensor (AP-10S) manufactured by KEYENCE can be used.

  On the other hand, the pressurizing / depressurizing pump 57 pressurizes or depressurizes the inside of the sealed container 51, and is installed in place of the vacuum pump 53 of FIG. For example, a diaphragm or a tube pump can be used as the pressure increasing / decreasing pump 57. If the inside of the sealed container 51 is always maintained in a negative pressure state by the pressure increasing / decreasing pump 57, the ink in the sealed container 51 is supplied to the sealed tank 20 while supplying ink from the sealed tank 20 to the inkjet head 1 at a constant flow rate. It becomes possible to return.

  The ink jet recording apparatus 102 of the present embodiment controls the flow rate of the ink supplied to the ink supply path 22b by controlling the rotation speed of the pressure increasing / decreasing pump 57. Specifically, the pressure of the pressure increasing / decreasing pump 57 is set so that liquid is fed to the inkjet head 1 at a certain ink flow rate in a state where the sealed container 51 is sealed. The pressure sensor 56 detects the pressure in the sealed container 51 while the pressure increasing / decreasing pump 57 is driven at the set pressure value and the pressure increasing / decreasing pump 57 is driven. Then, the output value (analog value) output from the pressure sensor 56 is monitored, and the number of rotations of the pressure increasing / decreasing pump 57 is controlled so that the output value approximates the set pressure value of the pressure increasing / decreasing pump 57. As a result, the deaerated ink can be supplied from the sealed tank 20 to the inkjet head 1 at an ink flow rate substantially the same as the ink flow rate at the set pressure value of the pressurizing and depressurizing pump 57.

  Furthermore, it is preferable that the rotation speed of the pressure increasing / decreasing pump 57 is controlled so that the pressure sensor 56 always shows a constant value. Thereby, the pressure value in the airtight container 51 is maintained constant. For example, when the ink flow rate returned from the sealed container 51 to the sealed tank 20 is larger than the ink flow rate supplied from the sealed tank 20 to the inkjet head 1, the pressure of the liquid feed pump 30 exceeds the pressure of the pressure-intensifying pump 57. . For this reason, the inside of the sealed container 51 is in a reduced pressure state, and the output value of the pressure sensor 56 becomes smaller than the set pressure value of the pressure increasing / decreasing pump 57. As a result, the ink flow rate varies. Therefore, in such a case, the inside of the sealed container 51 is pressurized by the pressurizing / depressurizing pump 57 so as to approximate the set pressure value. Thereby, the pressure in the airtight container 51 is always maintained at a constant value. Therefore, it is possible to feed ink into the ink flow path 11 of the inkjet head 1 at a constant flow rate.

  Thus, according to the present embodiment, the pressure in the sealed container 51 is kept constant by the pressure sensor 56 and the pressure increasing / decreasing pump 57. Therefore, unlike the inkjet recording apparatus 101 according to the fourth embodiment shown in FIG. 9, it is not necessary to provide the atmosphere release valve 54 and the two-way valve 55. That is, when returning ink from the sealed container 51 to the sealed tank 20, it is necessary to open the atmosphere in the sealed container 51 by opening the atmosphere release valve 54. There is no need to stop the flow of ink to the water.

[Embodiment 6]
FIG. 11 is a plan view showing the main configuration of the inkjet recording apparatus 103 according to the sixth embodiment. The ink jet recording apparatus 103 in FIG. 11 has substantially the same configuration as the ink jet recording apparatus 102 in the fifth embodiment shown in FIG. The ink jet recording apparatus 103 in FIG. 11 is different from the ink jet recording apparatus 102 in FIG. 10 in an ink supply path 22c.

  As shown in FIG. 11, the inkjet recording apparatus 103 is different from the inkjet recording apparatus 102 of FIG. 10 in that an ink bag 62 is provided in the sealed container 61 instead of the sealed container 51 of FIG. In the ink jet recording apparatus 103, the ink discharged from the ink jet head 1 is stored in the ink bag 62 in the sealed container 61. The ink bag 62 is connected to the pipe 29a and the pipe 29b.

  As described above, since the atmospheric pressure is not applied to the ink in the sealed tank 20 serving as the ink supply source, the ink does not flow unless the liquid feeding pump 30 and the pressure increasing / decreasing pump 57 are driven. Therefore, a sealed container 61 is provided so as to surround the periphery of the ink bag 62. Further, a pressure sensor 56 and a pressure increasing / decreasing pump 57 are connected to the sealed container 61. As a result, when the inside of the sealed container 61 is set to a negative pressure by the pressurizing / depressurizing pump 57, the ink bag 62 in the sealed container 61 is expanded. Along with this, ink is sent from the sealed tank 20 to the ink flow path 11 of the ink jet head 1, and the ink discharged from the ink jet head 1 is stored in the ink bag 62. Here, the ink bag 62 is connected to the pipe 29a and the pipe 29b, and the sealed container 61 is not connected to the pipe 29a and the pipe 29b. For this reason, even if the sealed container 61 is depressurized by the pressurizing / depressurizing pump 57 and the deaerated ink is sent to the ink bag 62, the deaerated ink is completely in contact with the air before being sent to the ink bag 62. There is no. Therefore, when the inside of the pipe 22c from the sealed tank 20 to the inkjet head 1 is empty, it is possible to suppress the air biting that occurs when the deaerated ink is supplied into the pipe 22c.

The ink bag 62 can have the same configuration as the sealed tank 20a in the third embodiment. For example, since the ink bag 62 holds the deaerated ink, the ink bag 62 is a material having a low air permeability of 1.0 m ³ / (m ² · 24 h · atm) or less, and has chemical resistance (ink resistance). It is preferable to comprise the material which has. For example, if the ink bag 62 is made of a PE film that is made of a high-strength and durable PE film obtained by laminating an aluminum foil or aluminum vapor-deposited film excellent in air shielding properties, the ink bag 62 becomes light and flexible. As such a high-strength and durable PE film, for example, an aluminum laminate film used for a silicon wafer case packaging gadget bag can be used. The ink bag 62 can be manufactured by thermocompressing the end of such a PE film at about 140 ° C. to process it into a bag shape. If the size of the ink bag 62 is thermocompression bonded at a 5 mm end in a PE film of W88 × D42 × H122 (mm), ink having a capacity of about 70 to 80 cc can be stored.

  In addition, as described above, the pressure sensor 56 is connected to the sealed container 61. The pressure sensor 56 controls the amount of ink sucked into the ink bag 62 accommodated in the sealed container 61. As the pressure sensor 56, for example, a pressure sensor (AP10S) manufactured by KEYENCE can be used. The pressure sensor 56 is connected to a dedicated amplifier (AP-80) (not shown). The pressure sensor 56 constantly monitors the pressure in the sealed container 61 from the output value analog-output from the dedicated amplifier. Then, by maintaining the inside 32 of the sealed container 61 in a negative pressure state, the ink is supplied from the sealed tank 20 to the inkjet head 1 at a constant flow rate, and from the ink bag 62 in which ink is accumulated by driving the liquid feeding pump 30. Ink can be returned to the sealed tank 20. In this way, the deaerated ink circulates in the ink supply path 22c.

  Here, a method for installing the ink bag 62 in the sealed container 61 will be described with reference to FIG. FIG. 12 is a diagram illustrating a configuration of the sealed container 61 of the inkjet recording apparatus 103. As shown in FIG. 12, the sealed container 61 includes a storage portion 61a that stores the ink bag 62 therein, and a lid portion 62b that covers the storage portion 61a and seals it. The pressure increasing / decreasing pump 57 is connected to the lid 62b.

  As shown in FIG. 12, the sealed container 61 has a configuration in which an opening formed in the accommodating portion 61a is closed with a lid portion 61b. The accommodating portion 61a and the lid portion 61b are fixed by screws 67. Thereby, the ink bag 62 connected to the lid part 61b is accommodated in the accommodating part 61a, and the inside of the sealed container 61 is in a sealed state.

  A flange portion (not shown) is formed on the lid portion 61b. On the other hand, the opening of the ink bag 62 is inserted into the spout part 63. With the O-ring 64 sandwiched between the flange portion and the spout portion 63, the spout portion 63 (ink bag 62) is fixed to the lid portion 61b by the screw 65. By fixing in this way, ink leakage from the ink bag 62 can be prevented. Moreover, the accommodating part 61a is being fixed so that it may surface-contact with the cover part 61b outside the spout part 63, and it has the structure which an air leak does not produce.

  Here, if the amount of ink stored in the ink bag 62 cannot be confirmed, there is a risk that ink will continue to accumulate in the ink bag 62 and eventually the ink bag 62 will burst. For this reason, it is preferable that the airtight container 61 is comprised from a transparent material. Thereby, the ink amount of the ink bag 62 accommodated in the sealed container 61 can be visually confirmed. For such a transparent material, for example, a transparent acrylic resin or PC resin can be used.

  Further, as shown in FIG. 12, an area sensor 66 and a light receiving sensor (not shown) are provided on the outer side of the sealed container 61. The light receiving sensor is provided on the opposite side of the area sensor 66 through the ink bag 62. As the area sensor 66, for example, an area sensor (LV-H100) manufactured by KEYENCE can be used. Each sensor is connected to a dedicated amplifier (for example, LV-51M manufactured by KEYENCE). Then, the change in the light shielding amount of each sensor due to the swelling of the ink bag 62 is monitored by analog output.

  FIG. 13 is a graph showing the result of confirming the relationship between the change in the amount of received light and the amount of ink in the ink bag 62 by monitoring the output value of each sensor in this way. When ink is fed into the ink bag 62, the ink bag 62 expands, and the amount of shielding the area sensor 66 increases. Therefore, if a threshold value for the shielding amount is set in the dedicated amplifier (LV-51M), a signal is output when the threshold value is exceeded, and it can be seen that the ink in the ink bag 62 exceeds the predetermined amount. Therefore, when the signal is output, the liquid feeding pump 30 is driven to control to feed the ink in the ink bag 62 to the sealed tank 20. Thereby, the deaerated ink supplied from the sealed tank 20 can be circulated in the ink supply path 22 without contacting the air in the ink supply path 22c. Accordingly, it is possible to exert an effect on the air remaining in the ink supply path 22c.

[Embodiment 7]
FIG. 14 is a plan view showing the main configuration of the inkjet recording apparatus 104 according to the seventh embodiment. The ink jet recording apparatus 104 in FIG. 14 has substantially the same configuration as the ink jet recording apparatus 103 in the sixth embodiment shown in FIG. The ink jet recording apparatus 104 in FIG. 14 is different from the ink jet recording apparatus 103 in FIG. 11 in an ink supply path 22d.

  In addition to the configuration of the inkjet recording apparatus 103 in FIG. 11, the inkjet recording apparatus 104 in FIG. 14 includes an ink bag 72 accommodated in a sealed container 71 (second sealed container) between the sealed tank 20 and the inkjet head 1. (Second ink bag). The sealed container 71 and the ink bag 72 are the same as the sealed container 61 and the ink bag 62. Further, similarly to the sealed container 61, a pressure sensor 73 and a pressure increasing / decreasing pump 74 are connected to the sealed container 71. These configurations of the inkjet recording apparatus 103 of FIG. 14 are different from those of the inkjet recording apparatus 103 of FIG. In the ink jet recording apparatus 104, the deaerated ink discharged from the sealed tank 20 is stored in the ink bag 72 before being supplied to the ink jet head 1. Then, the ink is supplied from the ink bag 72 to the inkjet head 1. Further, as in the ink jet recording apparatus 103 of the sixth embodiment, the ink discharged from the ink jet head 1 is stored in the ink bag 62, and the stored ink in the ink bag 62 is supplied to the sealed tank 20. The ink bag 72 is connected to the pipe 28a and the pipe 28b. A two-way valve 79 is provided in the pipe 28 a connecting the sealed tank 20 and the ink bag 72, and a two-way valve 69 is provided in the pipe 29 a connecting the ink jet head 1 and the ink bag 62. The two-way valve 69 opens or blocks the ink feeding from the inkjet head 1 to the ink bag 62. Similarly, the two-way valve 79 opens or blocks the ink feeding from the sealed tank 20 to the ink bag 72.

  In such an ink jet recording apparatus 104, first, in order to supply ink from the sealed tank 20 to the ink jet head 1, the two-way valve 79 is opened while the two-way valve 69 is closed. Next, the pressure in the sealed container 71 that accommodates the ink bag 72 is set to a negative pressure by the pressurizing / depressurizing pump 74. Thus, ink is fed from the sealed tank 20 to the ink bag 72 due to a water head difference between the ink bag 72 and the sealed tank 20. The airtight container 71 is also provided with an area sensor and a light receiving sensor as described in the sixth embodiment, so that the amount of ink in the ink bag 72 can be grasped.

  When the ink bag 72 is filled with ink, the two-way valve 79 is closed and the two-way valve 69 is opened. Further, the inside of the sealed container 61 is sucked by the pressure-reducing pump 57 connected to the sealed container 61 at a pressure equal to or higher than the pressure (negative pressure value) of the water head difference between the inkjet head 1 and the sealed container 61. Thereby, a meniscus is held with respect to the nozzle 12 of the inkjet head 1.

  On the other hand, the ink in the ink bag 72 can be sent to the ink jet head 1 by sucking at a pressure equal to or higher than the pressure (negative pressure value) of the water head difference applied to the ink bag 72 by the pressure increasing / decreasing pump 57. In addition, if the suction / reduction pump 57 sucks the ink from the ink bag 72 to the ink bag 62 at a pressure equal to or higher than the pressure (negative pressure value) necessary for feeding the ink, the ink in the ink bag 72 is removed from the inkjet head 1. Then, the liquid can be sent to the ink bag 62.

  As described above, the ink jet recording apparatus 104 adjusts the amount of ink supplied to the ink supply path 22d by controlling the pressure values of the pressure increasing / decreasing pump 57 and the pressure increasing / decreasing pump 74. That is, the meniscus of the nozzle 12 is not held by the sealed tank 20 but by the ink bags 62 and 72 having a remarkably small volume compared to the sealed tank 20.

  Thus, in this embodiment, the meniscus of the nozzle 12 can be controlled by the ink bags 62 and 72 having a smaller volume than the sealed tank 20. Thereby, it is not necessary to install a load cell or an electric slider in the sealed tank 20 as in the second embodiment (FIG. 3). Therefore, it is easy to design the large-capacity sealed tank 20, and mechanical parts such as a load cell and an electric slider are unnecessary. Therefore, the inkjet recording apparatus 104 is inexpensive.

[Embodiment 8]
FIG. 15 is a plan view showing the main configuration of the inkjet recording apparatus 105 according to the eighth embodiment. The ink jet recording apparatus 105 in FIG. 15 has substantially the same configuration as the ink jet recording apparatus 104 in the seventh embodiment shown in FIG. The ink jet recording apparatus 105 in FIG. 15 differs from the ink jet recording apparatus 104 in FIG. 14 in an ink formation path 21a and an ink supply path 22e.

  In the ink jet recording apparatus 105 of FIG. 15, the pipe 28 a connecting the sealed tank 20 and the ink bag 72 is branched in the ink jet recording apparatus 104 of FIG. 14, and the deaerated liquid is discharged from the deaeration module 23. Connected to the pipe 25. Further, a pipe 29 b that connects the ink bag 62 and the sealed tank 20 is also branched in the middle, and is connected to a pipe 24 that supplies ink discharged from the sealed tank 20 to the deaeration module 23. A two-way valve 81 is provided in the middle of the pipe 25 (before merging with the pipe 28a), and a two-way valve 82 is provided at a position until the sealed tank 20 branches to the pipe 24 and the pipe 29b. It has been. Moreover, in this embodiment, the liquid feeding pump 7 is provided in the piping 24 (before the deaeration module 23).

  In such an ink jet recording apparatus 105, when forming the deaerated ink in the ink forming path 21a, the two-way valve 79 is closed and the two-way valves 81 and 82 are opened. Then, the liquid feed pump 30 is driven after stopping the liquid feed pump 30 (power OFF). As a result, ink flows from the sealed tank 20 to the degassing module 23, degassed ink is formed, and the degassed ink returns to the sealed tank 20 again. Since the liquid feed pump 30 is stopped, ink does not flow from the ink bag 62 to the sealed tank 20. In this way, the deaerated ink can be formed by the ink forming path 21a.

  On the other hand, in the ink jet recording apparatus 105, when supplying deaerated ink to the ink supply path 22e, first, the two-way valves 79 and 81 are opened to temporarily supply ink to the ink bag 72. The valves 69 and 82 are closed. Next, the pressure in the airtight container 71 containing the ink bag 72 is set to a negative pressure by the pressurizing / depressurizing pump 74, the water head difference between the nozzle 12 and the ink bag 72 is maintained, and the meniscus of the opening formed in the nozzle 12 is maintained. Prevent destruction. At the same time, the degassed ink is sent to the ink bag 72 due to the water head difference between the ink bag 72 and the sealed tank 20.

  Next, while the two-way valve 79 is closed, the two-way valve 69 is opened. Furthermore, if the pressure-reducing pump 57 connected to the sealed container 61 sucks the ink bag 72 at a pressure equal to or higher than the pressure (negative pressure value) of the water head difference, the ink in the ink bag 72 is fed to the inkjet head 1. can do. In addition, if the suction / reduction pump 57 sucks the ink from the ink bag 72 to the ink bag 62 at a pressure equal to or higher than the pressure (negative pressure value) necessary for feeding the ink, the ink in the ink bag 72 is removed from the inkjet head 1. Then, the liquid can be sent to the ink bag 62. In this manner, the formed deaerated ink can be supplied to the ink supply path 22e while the deaerated ink is formed in the ink forming path 21a.

  Further, when ink is returned from the ink bag 62 to the sealed tank 20, the two-way valve 69 and the two-way valves 79 and 82 are closed. Further, the two-way valve 81 is opened. The liquid feed pump 7 (for example, a tube pump) is driven, and the liquid feed pump 30 is driven under the same liquid feed conditions. As a result, the ink can be returned from the ink bag 62 to the sealed tank 20.

  As described above, in the inkjet recording apparatus 105 of the present embodiment, the branch point is provided in the pipe 28 a that connects the sealed tank 20 and the sealed container 71, and the pipe 25 that feeds the ink discharged from the deaeration module 23. It is connected to the. Further, a branch point is provided in the pipe 29 b that connects the ink bag 62 and the sealed tank 20, and the branch point is connected to the pipe 24 that supplies the ink in the sealed tank 20 to the deaeration module 23. Thus, the ink in the sealed tank 20 can be deaerated while being ejected by the inkjet head 1 only with a spout that supplies ink from the sealed tank 20 to the ink bag 72.

  That is, since it is not necessary to provide spouts in the ink bag 62, the number of spouts can be reduced. Thereby, the cost for producing the ink bag 62 is reduced. That is, in the process of thermocompression bonding the spout to the ink bag 62, the temperature variation of the jig for crimping the spout is uneven and a non-uniform load is applied during the pressure bonding. For this reason, since it is difficult to produce an ink bag that can withstand the internal pressure of the ink bag 62, the smaller the number of spouts, the higher the efficiency of producing the bag and the lower the unit price of the bag.

In addition, this invention can also be expressed as follows.
[1] A system for supplying degassed liquid to an inkjet head, wherein a sealed tank storing the liquid, a pipe for discharging the liquid from the tank, a pipe for returning the discharged liquid, and the pipe A degassing module for degassing a gas dissolved in the liquid, a circulation system including a vacuum pump for evacuating the degassing module, an inkjet head, and supplying the degassed liquid to the head A deaeration system (liquid supply device) comprising a piping and a circulation system provided with piping for discharging liquid without being discharged by the head and returning liquid to the tank.

  According to this, the ink is supplied to the deaeration module from the sealed tank that stores the ink to be supplied to the inkjet head that discharges the ink, and the supplied ink passes through the deaeration module that is held at a negative pressure by a vacuum pump. Low air concentration due to the circulation system consisting of piping that returns to the sealed tank and the circulation system that includes piping that supplies ink from the sealed tank to the inkjet head and returns the ink discharged from the head to the sealed tank again. It is possible to produce degassed ink and supply the degassed ink to the inkjet head at a high flow rate to dissolve the air remaining in the piping, and to circulate the ink that has not been ejected by the inkjet head. Thus, by using it again, the effect of reducing wasteful ink consumption can be obtained.

  [2] A deaeration system in a deaeration system, wherein the air tank stores the liquid according to [1], and the air tank is composed of a cylinder and a piston.

  [3] A degassing system in a degassing system, wherein the liquid tank according to [1] is stored and the sealed tank is constituted by a bag.

  [4] A degassing system characterized in that it is a sealed tank having a bag structure storing the liquid according to [3], wherein a film forming the bag is laminated with a metallic film.

  Further, as in [2], the sealed tank for storing the liquid may be composed of a cylinder and a piston, and the meniscus of the inkjet head can be controlled by controlling the piston with an electric slider and a load cell. Further, the sealed tank may be constituted by a bag as in [3], and more specifically, a metal film may be laminated on the film constituting the bag as in [4]. Thereby, it can store, maintaining the oxygen concentration of the deaerated liquid.

  [5] A circulation system including a pipe that is discharged without being ejected by the ink jet head according to [1] and returns the liquid to the sealed tank according to [1], wherein the liquid can come and go in the pipe. A mold tank is connected, and the closed tank is provided with a pump for sucking the inside of the tank, and a pump for sending liquid is connected to the pipe connecting the closed tank and the closed tank described in [1]. A circulation system in a degassing system characterized by

  According to this, by connecting a sealed tank in which the liquid can come and go in a pipe for returning the liquid discharged without being discharged by the inkjet head to the sealed tank, and by sucking the air in the tank with the vacuum pump, the inkjet head Since the liquid is supplied to the liquid, the liquid can be fed at a stable flow rate without pulsating the liquid.

  [6] A circulation system including a pipe that is discharged without being ejected by the ink jet head according to [1], and returns the liquid to the sealed tank according to [1], and only the liquid can go back and forth in the pipe that returns the liquid. A sealed tank is connected, and the sealed tank is provided with a pump capable of increasing / decreasing the inside of the tank and a pressure sensor for monitoring the pressure in the tank, and between the sealed tank and the sealed tank according to claim 1. A circulation system in a deaeration system, wherein a pump for feeding a liquid is connected to a pipe to be connected.

  According to this, in the piping that returns the liquid discharged without being discharged by the inkjet head to the sealed tank, a sealed tank that can only go and go to the liquid is connected, and the pressure inside the tank is increased and decreased while monitoring the pressure in the tank Therefore, the liquid can be supplied to the ink jet head even when the ink is returned by the liquid feed pump when the liquid is collected in the sealed tank.

  [7] A circulation system including a pipe that is discharged without being discharged by the ink jet head according to [1] and returns the liquid to the sealed tank according to [1], wherein only the liquid is contained in the pipe that returns the liquid. A sealed tank capable of going back and forth is connected, and the sealed tank is provided with a pump capable of pressurizing and depressurizing the inside of the tank, a pressure sensor for monitoring the pressure in the tank, and an ink bag capable of storing ink. ] Is connected to a pump connecting liquid between the sealed tanks, and the liquid discharged from the inkjet head passes through the ink bag accommodated in the sealed container, and the sealed tank Circulation system in a degassing system characterized by returning to

  According to this, an ink bag may be placed in the tank by connecting a sealed tank capable of only going to and from the liquid to a pipe that returns the liquid discharged without being discharged by the inkjet head to the sealed tank. The pressure is monitored with a pressure sensor, and the air in the tank is pressurized and depressurized to expand and contract the ink bag, so that liquid can be supplied to the inkjet head and deaerated into a sealed tank that stores the ink It is possible to return the ink without touching the outside air.

  [8] A circulation system including a pipe for supplying degassed liquid to the inkjet head according to [1] and a pipe for discharging the liquid without being discharged by the head and returning the liquid to the tank. A sealed tank that allows only liquid to come and go is connected in the pipe and the pipe that returns the liquid, and the sealed tank has a pump that can pressurize and depressurize the tank, a pressure sensor that monitors the pressure in the tank, and an ink that can store ink A bag is provided, and a pump for feeding liquid is connected to the pipe connecting the sealed tank and the sealed tank described in [1], and the degassed liquid is sealed in [1]. The liquid supplied to the ink jet head through an ink bag provided in a pipe supplied from the tank, and the liquid discharged from the ink jet head is stored in the sealed container. Circulation system in deaeration system according to claim altering the closed tank through.

  According to this, the pipe that returns the liquid discharged without being discharged by the inkjet head to the sealed tank, and the sealed tank that can only move the liquid from the sealed tank that stores the liquid to the pipe that supplies the liquid to the inkjet head. The ink bag may be connected and placed in the tank. The pressure inside the tank is monitored by a pressure sensor, and the ink bag is expanded and contracted by increasing and decreasing the pressure of the air in the tank. The liquid can be supplied, and the meniscus of the nozzle of the inkjet head can be maintained by always controlling the inside of the sealed container with a negative pressure.

  [9] In the circulation system according to [8], the liquid is sent to a degassing module equipped with a vacuum pump in a pipe between the closed tank described in [1] and a closed tank installed in a pipe supplying liquid. A pipe for branching liquid is branched, and a pipe through which a liquid is discharged through a degassing module is connected in a pipe between the liquid feed pump returning to the sealed tank described in [1] and the sealed tank described in claim 1. A circulation system in the deaeration system.

  According to this, the pipe for feeding the liquid to the degassing module equipped with the vacuum pump is branched in the pipe between the sealed tank and the sealed tank installed in the pipe for supplying the liquid, and passes through the degassing module. The pipe from which the liquid is discharged is connected to the pipe between the liquid feed pump returning to the closed tank [1] and the closed tank [1].

  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.

  ADVANTAGE OF THE INVENTION According to this invention, the residual air in a path | route can be dissolved in deaeration liquid, and the inkjet recording device provided with the deaeration module which can discharge the deaeration liquid stably from the inkjet head can be provided. .

FIG. 2 is a plan view showing the main configuration of the ink jet recording apparatus according to Embodiment 1 of the present invention. It is a top view which shows the principal part structure of the inkjet recording device of Embodiment 2 of this invention. FIG. 3 is a diagram for explaining a configuration of a sealed tank in the ink jet recording apparatus of FIG. 2. FIG. 3 is a plan view showing a configuration in which an oxygen concentration meter is installed in order to confirm the effect of the ink jet recording apparatus of FIG. 2. 5 is a graph showing the relationship between the oxygen concentration of the ink in the ink formation path and the deaeration time when the ink is fed at 5 cc / min in the ink jet recording apparatus of FIG. 5 is a graph showing the relationship between the oxygen concentration of the ink in the ink formation path and the deaeration time when the ink is fed at 20 cc / min in the ink jet recording apparatus of FIG. 6 is a graph showing the relationship between the remaining amount of air in the ink supply path and the liquid supply time when ink is supplied at 1 cc / min or 10 cc / min in the ink jet recording apparatus of FIG. 4. It is sectional drawing which shows the structure of a bag-shaped airtight tank. It is a top view which shows the principal part structure of the inkjet recording device of Embodiment 4 of this invention. It is a top view which shows the principal part structure of the inkjet recording device of Embodiment 5 of this invention. It is a top view which shows the principal part structure of the inkjet recording device of Embodiment 6 of this invention. It is a figure which shows the structure of the airtight container in the inkjet recording device of FIG. 13 is a graph showing the relationship between the amount of ink in the sealed container of FIG. 12 and the amount of light received by the area sensor. It is a top view which shows the principal part structure of the inkjet recording device of Embodiment 7 of this invention. It is a top view which shows the principal part structure of the inkjet recording device of Embodiment 8 of this invention.

Explanation of symbols

1 Inkjet head 2 Ink supply device (liquid supply device)
10 Inkjet recording apparatus 20 Sealed tank 21 Ink formation path (first path)
22 Ink supply path (second path)
23 Deaeration module (deaeration part)
27, 30 Liquid feed pump 31 Cylinder 32 Piston 41 Aluminum film (metal film)
51, 61 Airtight container 56 Pressure sensor 62 Ink bag 71 Airtight container (second airtight container)
72 Ink bag (second ink bag)
74 Pressure-reducing pump 90 Waste liquid tank 100-106 Inkjet recording device 122 Ink supply path (second path)

Claims (16)

A liquid supply device for supplying liquid discharged from an inkjet head,
A closed tank in which the liquid is stored;
A degassing part for degassing the dissolved gas in the liquid in the sealed tank,
A first path in which liquid discharged from the sealed tank is sent to the degassing unit, and the degassed liquid formed in the degassing unit returns to the sealed tank;
A liquid supply apparatus, wherein the second path through which the degassed liquid in the sealed tank is supplied to the inkjet head is provided independently of each other.   2. The liquid supply apparatus according to claim 1, wherein the deaeration liquid is supplied to the inkjet head through the second path while the deaeration liquid is formed through the first path. The degassed liquid formed in the first path circulates in the first path,
The second path further includes a path for returning the deaerated liquid discharged without being discharged from the inkjet head to the sealed tank,
The liquid supply apparatus according to claim 1, wherein the degassed liquid discharged from the ink jet head circulates in the second path.   The liquid supply apparatus according to any one of claims 1 to 3, wherein a flow rate of the liquid or deaeration liquid flowing through the first path is larger than a flow rate of the deaeration liquid flowing through the second path. In the second path, in the path that is discharged without being discharged from the inkjet head, a liquid feed pump is provided,
The liquid supply apparatus according to claim 3, wherein the liquid feed pump applies a negative pressure to the inkjet head to supply the deaerated liquid from the sealed tank to the second path.   The liquid supply according to any one of claims 1 to 5, wherein the closed tank reduces the volume of the closed tank as the liquid or degassed liquid in the closed tank decreases. apparatus.   The liquid supply apparatus according to claim 6, wherein the sealed tank includes a cylinder in which the liquid or degassed liquid is stored and a piston that discharges the liquid in the cylinder when pressed.   The liquid supply apparatus according to claim 6, wherein the sealed tank is formed in a bag shape.   9. The liquid supply apparatus according to claim 8, wherein the surface of the sealed tank is laminated with a metal film. In the second path, a sealed container for storing the deaerated liquid discharged without being discharged from the inkjet head is provided.
The liquid supply apparatus according to claim 5, wherein the liquid feed pump is connected to an airtight container. A pressurizing / depressurizing pump for pressurizing or depressurizing the sealed container;
A pressure sensor for detecting the pressure in the sealed container,
The number of revolutions of the pressure increasing / decreasing pump is controlled so that an output value of the pressure sensor approximates a set pressure value of the pressure increasing / decreasing pump at which the inside of the sealed container has a predetermined pressure. Liquid supply device. An ink bag for storing a degassed liquid is provided inside the sealed container.
The liquid supply apparatus according to claim 11, wherein the sealed container and the ink bag are blocked. A second ink bag for storing the degassed liquid discharged from the sealed tank and a second sealed container for accommodating the second ink bag are provided in a path between the sealed tank and the inkjet head in the second path. ,
The pressurization / decompression pump controls the sealed container and the second sealed container to a negative pressure, thereby feeding the degassed liquid discharged from the sealed tank in the order of the second ink bag, the inkjet head, and the ink bag. The liquid supply apparatus according to claim 12, characterized in that: The second path is branched in the path between the sealed tank and the inkjet head, and the branched path is connected to a path through which the degassed liquid discharged from the deaeration unit is sent to the sealed tank. ,
The second path is further branched in a path between the sealed tank and the ink bag, and the branched path is connected to a path through which liquid in the sealed tank is fed to the deaeration unit. The liquid supply apparatus according to claim 13.   The liquid supply apparatus according to claim 1, further comprising a waste liquid tank in which a degassed liquid discharged without being discharged from the inkjet head is stored.   An ink jet recording apparatus comprising: the liquid supply apparatus according to claim 1; and an ink jet head.

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