Liquid ejection device

Abstract

To provide a liquid ejection device that prevents a liquid that has leaked from a deaeration unit from flowing into another deaeration unit.SOLUTION: A liquid ejection device 1 includes: an ejection head 50; a first flow passage member L1 that defines a flow passage for a first liquid supplied to the ejection head 50; a second flow passage member L2 that defines a flow passage for a second liquid supplied to the ejection head 50; a first deaeration unit 15 that removes dissolved gas from the first liquid in the first flow passage member L1; a second deaeration unit 25 that removes dissolved gas from the second liquid in the second flow passage member L2; a decompression generating device 40 that decompresses the first deaeration unit 15 and the second deaeration unit 25; a gas passage member G that connects the decompression generating device 40, the first deaeration unit 15, and the second deaeration unit 25 by branching off from a passage. A first regulating member 16 that regulates movement of a fluid flowing toward the first deaeration unit 15 is installed in the gas passage member G1 closer to the first deaeration unit 15 than a joint member 30. A second regulating member 26 that regulates movement of the fluid flowing toward the second deaeration unit 25 is installed in a gas passage member G2 closer to the second deaeration unit 25 than the joint member 30.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid ejection device.

Background Art

[0002] Conventionally, a liquid ejection device that performs a degassing process on a liquid such as ink and then supplies it to a discharge head has been known. For example, Patent Document 1 discloses a degassing method using a degassing unit including a gas permeable membrane.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique described in Patent Document 1, when a plurality of degassing units are operated by a single vacuum pump, there is a problem that ink leaked from one degassing unit easily flows into other degassing units. Specifically, when the gas permeable membrane is damaged during the operation of the vacuum pump, ink leaks into the pipe connected from the degassing unit to the vacuum pump, and eventually reaches near the vacuum pump. When the vacuum pump is stopped in this state, the leaked ink may flow backward, and the ink may flow into a normal degassing unit through a joint where a plurality of the above pipes are joined together.

[0005] Further, when there is a height difference in the arrangement of a plurality of degassing units, or when the diameter of the pipe connecting the degassing unit and the vacuum pump is relatively large, there is a risk that the ink leaking into the normal degassing unit may flow in even while the vacuum pump is operating. In a normal degassing unit, if ink flows into the part communicating with the vacuum pump, the degassing unit becomes unusable and must be replaced. That is, there has been a demand for a liquid discharge device that prevents the liquid leaked from the degassing section, which is a degassing unit, from flowing into other degassing sections.

Means for Solving the Problems

[0006] The liquid discharge device includes a discharge head that discharges a first liquid and a second liquid to a medium, a first flow path member that defines a flow path of the first liquid supplied to the discharge head, a second flow path member that defines a flow path of the second liquid supplied to the discharge head, a first degassing section provided in the first flow path member for removing dissolved gas from the first liquid in the first flow path member, a second degassing section provided in the second flow path member for removing dissolved gas from the second liquid in the second flow path member, a decompression generating device for decompressing the first degassing section and the second degassing section, and a gas path member that branches in the middle of the path to connect the decompression generating device with the first degassing section and the second degassing section. A first restricting member for restricting the movement of the fluid from the branch position toward the first degassing section is installed in the gas path member closer to the first degassing section than the branch position, and a second restricting member for restricting the movement of the fluid from the branch position toward the second degassing section is installed in the gas path member closer to the second degassing section than the branch position.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0008] In the embodiments described below, an inkjet printer that discharges ink for printing is exemplified as the liquid discharge device 1, and will be described with reference to the drawings. The liquid discharge device 1 is an industrial or commercial inkjet printer that uses a relatively large amount of ink. Note that the liquid discharge device of the present invention is not limited to industrial and commercial use.

[0009] In the following figures, the XYZ axes are attached as coordinate axes orthogonal to each other as necessary, the direction indicated by each arrow is the + direction, and the direction opposite to the + direction is the - direction.

[0010] As shown in FIG. 1, the liquid discharge device 1 according to the present embodiment includes a discharge head 50, a first flow path member L1, a second flow path member L2, a first degassing section 15, a second degassing section 25, a decompression generation device 40, a gas path member G, and a notification section 70, etc. Also, although not shown in the drawings, the liquid discharge device 1 also includes a control section. The control section integrally controls the operation of each component provided in the liquid discharge device 1. Note that FIG. 1 also shows the state during printing of the liquid discharge device 1, the solid-line arrows are the flow of the first liquid or the second liquid, and the dashed-line arrows are mainly the flow of gas.

[0011] The discharge head 50 discharges the first liquid and the second liquid onto a medium such as cloth, paper, a resin sheet, and a resin film, adheres them, and performs printing. A known inkjet head is applied to the discharge head 50. Examples of the driving means of a known inkjet head include a piezoelectric element, an electromechanical conversion element that displaces a diaphragm by electrostatic adsorption, and an electrothermal conversion element that uses bubbles generated by heating.

[0012] The first liquid and the second liquid are, for example, any of the inks exhibiting various colors such as black, cyan, magenta, and yellow. In addition to the above inks, clear ink, coating liquid, pretreatment liquid, post-treatment liquid, etc. may be applied as the first liquid and the second liquid.

[0013] In addition to the first liquid and the second liquid, the liquid ejection device 1 may be configured to eject other liquids such as other inks from the ejection head 50. That is, in addition to the configuration for supplying the first liquid to the ejection head 50 and the configuration for supplying the second liquid to the ejection head 50, the liquid ejection device 1 may further include one or more similar configurations. For example, color printing becomes possible if three or more inks such as cyan, magenta, and yellow are used. Details of the above configuration will be described later.

[0014] Although illustration is omitted, the ejection head 50 has a plurality of nozzle rows. Each nozzle row individually corresponds to the first liquid and the second liquid. Each nozzle row consists of a plurality of nozzles. Droplets of the corresponding first liquid and second liquid are ejected from the plurality of nozzles, and printing is performed on the medium.

[0015] The first flow path member L1 is a pipe for supplying the first liquid to the ejection head 50. In the first flow path member L1, a first liquid tank 11, a pressure pump 12, a filter 13, a sub-tank 14, and a first degassing section 15 are arranged in this order from upstream toward the ejection head 50. The first liquid flows in the first flow path member L1. The first flow path member L1 defines a flow path of the first liquid supplied to the ejection head 50. The first liquid is conveyed through the first flow path member L1 in the above order with the above configuration.

[0016] The second flow path member L2 is a pipe that supplies the second liquid to the discharge head 50. In the second flow path member L2, a second liquid tank 21, a pressure pump 22, a filter 23, a sub-tank 24, and a second degassing unit 25 are arranged in this order from upstream toward the discharge head 50. The second liquid flows through the second flow path member L2. The second flow path member L2 defines a flow path for the second liquid to be supplied to the discharge head 50. The second liquid is conveyed through the second flow path member L2 in the above-described order with the above-described configuration.

[0017] Valves or the like may be appropriately installed in the first flow path member L1 and the second flow path member L2. Note that the above-described configuration and arrangement are merely examples and are not limited thereto.

[0018] The configuration in which the first liquid flows and the configuration in which the second liquid flows have similar operations and functions. Therefore, the configuration in which the first liquid flows will be described as a representative example, and the description of the configuration in which the second liquid flows will be omitted.

[0019] The first liquid tank 11 stores the first liquid. The capacity of the first liquid tank 11 is larger than the capacity of the downstream sub-tank 14. The user of the liquid discharge device 1 can pour and replenish the first liquid into the first liquid tank 11.

[0020] In the space within the first liquid tank 11, the liquid surface of the first liquid is exposed. When the first liquid is replenished or while it is stored in the first liquid tank 11, gases such as oxygen are likely to dissolve in the first liquid and become dissolved gases. If the first liquid contains a large amount of dissolved gas, the size and ejection manner of the droplets of the first liquid ejected from the discharge head 50 may become unstable. In contrast, the liquid discharge device 1 is provided with a first degassing unit 15 that removes the dissolved gas in the first liquid.

[0021] The pressure pump 12 pumps the first liquid in the first liquid tank 11 downstream. A known liquid feeding pump can be applied to the pressure pump 12.

[0022] Filter 13 also removes relatively fine foreign matter and the like contained in the first liquid. This suppresses the occurrence of clogging in the piping due to foreign matter and clogging of the nozzles of the discharge head 50. Examples of the filter 13 include a mesh filter made of metal or resin, and a membrane filter made of resin or paper.

[0023] The sub-tank 14 is located immediately before the first degassing section 15 and temporarily stores the first liquid.

[0024] The first degassing section 15 is provided in the first flow path member L1. Connected to the first degassing section 15 are a first flow path member L1 through which the first liquid flows and a gas path member G1 that communicates with the decompression generating device 40. Although details will be described later, in the first degassing section 15, the dissolved gas in the first liquid is sucked out from the first liquid flowing in the first flow path member L1 to the gas path member G1. That is, the first degassing section 15 removes the dissolved gas from the first liquid in the first flow path member L1. The first liquid is further conveyed through the first degassing section 15 and then through the first flow path member L1 to reach the discharge head 50.

[0025] As described above, the description of the configuration for supplying the second liquid to the discharge head 50 is omitted, but the second degassing section 25 has the same mechanism as the first degassing section 15, is provided in the second flow path member L2, and removes the dissolved gas from the second liquid in the second flow path member L2. The second liquid is conveyed through the second degassing section 25 and then through the second flow path member L2 to reach the discharge head 50.

[0026] The gas path members G1, G2, and G3 are basically pipes through which gas flows. Hereinafter, the gas path members G1, G2, and G3 may also be collectively referred to as the gas path member G.

[0027] The gas path member G connects the first degassing section 15 and the second degassing section 25 to the decompression generator 40 by branching in the middle of the path. Specifically, the gas path member G1 connects the first degassing section 15 and the joint member 30. A first regulating member 16 is installed in the middle of the gas path member G1. The gas path member G2 connects the second degassing section 25 and the joint member 30. A second regulating member 26 is installed in the middle of the gas path member G2.

[0028] The first regulating member 16 is installed in the gas path member G1 closer to the first degassing section 15 than the joint member 30 which is the branching position of the gas path member G. The first regulating member 16 has a function of preventing the backflow of a fluid such as a liquid or a gas in the gas path member G1. Specifically, the first regulating member 16 does not prevent the movement of the fluid from the first degassing section 15 toward the joint member 30, and regulates the movement of the fluid from the joint member 30 toward the first degassing section 15.

[0029] The second regulating member 26 is installed in the gas path member G2 closer to the second degassing section 25 than the joint member 30 which is the branching position of the gas path member G. The second regulating member 26 has a function of preventing the backflow of a fluid such as a liquid or a gas in the gas path member G2. Specifically, the second regulating member 26 does not prevent the movement of the fluid from the second degassing section 25 toward the joint member 30, and regulates the movement of the fluid from the joint member 30 toward the second degassing section 25.

[0030] The first regulating member 16 and the second regulating member 26 are check valves. Known check valves can be applied to the first regulating member 16 and the second regulating member 26.

[0031] The above-mentioned liquid or gas as the fluid is the first liquid or the second liquid, dissolved gas, air in the gas path member G, etc. Although it will be described in detail later, when a problem occurs in the first degassing section 15 and the second degassing section 25, the first liquid or the second liquid may leak into the gas path member G and flow. The joint member 30 merges two pipes of the gas path member G1 and the gas path member G2 into one gas path member G3. The gas path member G3 connects the joint member 30 and the decompression generator 40.

[0032] The decompression generating device 40 decompresses the first degassing section 15 and the second degassing section 25 via the gas path member G. The dissolved gas in the first liquid is degassed in the first degassing section 15 and sucked into the decompression generating device 40 when the decompression generating device 40 decompresses the inside of the gas path member G. Similarly, the dissolved gas in the second liquid is degassed in the second degassing section 25 and sucked into the decompression generating device 40 when the decompression generating device 40 decompresses the inside of the gas path member G.

[0033] The decompression generating device 40 is a vacuum ejector. A compressed air pump 41 and a storage section 43 are attached to the decompression generating device 40. The decompression generating device 40 decompresses the inside of the gas path member G by the Venturi effect of the compressed air generated by the compressed air pump 41. A known vacuum ejector can be applied to the decompression generating device 40.

[0034] In the liquid ejection device 1, the decompression generating device 40 integrally decompresses the first degassing section 15 and the second degassing section 25. Due to the configuration of the device, it is possible to install the decompression generating device 40 in each of the first degassing section 15 and the second degassing section 25, but this will cause the device to become larger and the cost to increase. Therefore, the decompression generating device 40 may integrally decompress more degassing sections in addition to the first degassing section 15 and the second degassing section 25. In this case, a regulating member corresponding to each of the degassing sections is installed.

[0035] The storage section 43 receives the compressed air of the compressed air pump 41 discharged from the decompression generating device 40. The above-mentioned compressed air may contain an oil mist contained in the compressed air pump 41. The storage section 43 also serves as an oil pan for storing the oil mist.

[0036] In addition, when a malfunction occurs, the first liquid and the second liquid that have leaked out flow into the storage unit 43. Specifically, the leaked first liquid and second liquid are discharged into the storage unit 43 via the gas path member G and the decompression generator 40. That is, the storage unit 43 stores the first liquid or the second liquid as the liquid contained in the dissolved gas sucked by the decompression generator 40. Thereby, when leakage of the first liquid or the second liquid occurs, leakage of the first liquid and the second liquid from the decompression generator 40 can be suppressed.

[0037] As the decompression generator 40, for example, a vacuum pump may be applied instead of the vacuum ejector. When a vacuum pump is applied to the decompression generator 40, the compressed air pump 41 is omitted.

[0038] A sensor 60 is provided in the storage unit 43. The sensor 60 detects the first liquid or the second liquid that has flowed into the storage unit 43. The sensor 60 is a liquid leakage sensor. Specifically, as the sensor 60, a known liquid leakage sensor such as a conductivity detection type or an optical detection type is applied according to the characteristics of the first liquid and the second liquid. The result of the liquid leakage detection by the sensor 60 is transmitted to the notification unit 70.

[0039] The notification unit 70 is electrically connected to the sensor 60. The notification unit 70 notifies the user of the liquid discharge device 1 of the leakage of the first liquid and the second liquid based on the detection result of the liquid leakage by the sensor 60. Thereby, the user can quickly respond to the occurrence of leakage.

[0040] Examples of the notification unit 70 include a lamp and a buzzer. Further, the sensor 60 may be electrically connected to the control unit, and the detection result of the sensor 60 may be transmitted to the control unit. In this case, the function of the notification unit 70 may be assigned to the display panel of the liquid discharge device 1 or the information terminal that operates the liquid discharge device 1.

[0041] As shown in FIG. 2, the first degassing section 15 includes a main body 151 and connecting sections 153, 155, 157. The main body 151 is substantially cylindrical, and the height direction of the cylinder is along the Z-axis. Inside the main body 151, an air chamber and a liquid chamber (not shown) are provided.

[0042] The connecting section 153 is disposed on the side surface closer to the -Z direction with respect to the main body 151. The connecting section 153 communicates the first flow path member L1 on the upstream side of the first degassing section 15 with the liquid chamber of the main body 151. The connecting section 155 is disposed on the top portion in the +Z direction with respect to the main body 151. The connecting section 155 communicates the liquid chamber of the main body 151 with the first flow path member L1 on the downstream side of the first degassing section 15.

[0043] With the above configuration, during printing of the liquid ejection device 1, the first liquid flows into the liquid chamber in the main body 151 through the connecting section 153, and after flowing through the liquid chamber, it flows out from the main body 151 through the connecting section 155.

[0044] The connecting section 157 is disposed at the bottom in the -Z direction with respect to the main body 151. The connecting section 157 communicates the air chamber of the main body 151 with the decompression generating device 40 through the first regulating member 16, the gas path member G, etc. Thereby, the decompression generated by the decompression generating device 40 decompresses the air chamber of the main body 151.

[0045] The air chamber and the liquid chamber of the main body 151 are separated by a gas permeable membrane. The gas permeable membrane does not permeate liquid but permeates gas. When the air chamber is decompressed while flowing the first liquid in the liquid chamber, the dissolved gas in the first liquid passes through the gas permeable membrane and permeates into the air chamber. Thereby, the dissolved gas in the first liquid is degassed. The degassed first liquid flows out from the connecting section 155, and the sucked dissolved gas is sucked from the connecting section 157 to the gas path member G1.

[0046] If the first degassing section 15 is normal, the first liquid will not leak into the air chamber. However, if holes or tears through which the liquid can pass occur in the gas permeable membrane, the first liquid may leak into the air chamber. The first liquid that has leaked into the air chamber is sucked together with the dissolved gas and flows through the gas path member G toward the decompression generator 40. The leakage into the gas path member G will be described later.

[0047] The second degassing section 25 has the same configuration and the same function as the first degassing section 15. Therefore, the description of the second degassing section 25 is omitted. Known degassing modules can be applied to the first degassing section 15 and the second degassing section 25.

[0048] As shown in FIG. 3, when the decompression generator 40 is in operation, compressed air is sent from a compressed air pump 41 (not shown) to the decompression generator 40 through a pipe 41p. The compressed air is discharged from the decompression generator 40 to a storage section 43 (not shown) through a pipe 43p. The decompression generated by the decompression generator 40 spreads to the air chamber of the first degassing section 15 and the air chamber of the second degassing section 25 through the gas path member G.

[0049] Here, a state where the gas permeable membrane of the second degassing section 25 is damaged and the second liquid leaks into the air chamber of the second degassing section 25 will be described. In FIGS. 3 and 4, the flow of the fluid is indicated by an arrow, the flow of the gas is shown as white, and the flow of the gas mixed with the second liquid is shown as filled. Also, in FIGS. 3 and 4, the illustration of the first flow path member L1, the second flow path member L2, etc. is omitted.

[0050] Since the first degassing section 15 is normal, gas is sucked in the gas path member G1. In the second degassing section 25, the second liquid is mixed into the gas, and the gas mixed with the second liquid is sucked in the gas path member G2. At the joint member 30, the gas from the first degassing section 15 and the gas mixed with the second liquid from the second degassing section 25 merge. That is, the gas mixed with the second liquid flows from the joint member 30 to the decompression generator 40 and further to the pipe 43p.

[0051] The second liquid reaching the storage unit 43 is detected by the above-described sensor 60. When a malfunction is recognized by the notification of the notification unit 70 or the like, the user of the liquid discharge device 1 stops the operation of the liquid discharge device 1. When the operation of the liquid discharge device 1 is stopped, the pneumatic pump 41 also stops.

[0052] When the pneumatic pump 41 stops, the reduced pressure generated by the decompression generator 40 is eliminated, resulting in a backflow. Specifically, as shown in FIG. 4, in the gas path member G, the gas containing the second liquid flows backward from the decompression generator 40 toward the first degassing unit 15 and the second degassing unit 25. At this time, the gas containing the second liquid exists in the gas path member G3. Therefore, the gas containing the second liquid also flows backward through the gas path member G1 and heads toward the normal first degassing unit 15.

[0053] A first restricting member 16 is installed in the gas path member G1 between the first degassing unit 15 and the decompression generator 40. The first restricting member 16 does not prevent the movement of the fluid from the first degassing unit 15 toward the decompression generator 40, but restricts and blocks the movement of the fluid from the decompression generator 40 toward the first degassing unit 15. Therefore, the above backflow is stopped by the first restricting member 16 and does not flow into the gas chamber of the first degassing unit 15.

[0054] Also, during normal operation of the second degassing unit 25, the gas permeable membrane of the first degassing unit 15 may be damaged and the first liquid may leak into the gas chamber. In this case, in the same manner as above, the inflow of the first liquid into the gas chamber of the second degassing unit 25 is restricted by the second restricting member 26.

[0055] In the present embodiment, the first restricting member 16 is arranged close to the first degassing unit 15 and the second restricting member 26 is arranged close to the second degassing unit 25. However, the arrangements of the first restricting member 16 and the second restricting member 26 are not limited to the above. The first restricting member 16 may be installed in the gas path member G1, for example, it may be arranged close to the joint member 30. Similarly, the second restricting member 26 may be installed in the gas path member G2, for example, it may be arranged close to the joint member 30.

[0056] According to this embodiment, the following effects can be obtained.

[0057] It is possible to prevent the inflow of the first liquid leaked from the first degassing section 15 into the second degassing section 25 and the inflow of the second liquid leaked from the second degassing section 25 into the first degassing section 15. Therefore, it is possible to provide the liquid discharge device 1 that prevents the spread of the influence caused by the leakage of the first liquid and the second liquid.

Explanation of reference numerals

[0058] 1... liquid discharge device, 15... first degassing section, 16... first restricting member, 25... second degassing section, 26... second restricting member, 30... joint member as a branch position, 40... decompression generating device, 43... storage section, 50... discharge head, 60... sensor, 70... notification section, G, G1, G2, G3... gas path members, L1... first flow path member, L2... second flow path member.

Claims

1. A discharge head that discharges a first liquid and a second liquid onto a medium, a first flow path member that defines a flow path of the first liquid supplied to the discharge head, a second flow path member that defines a flow path of the second liquid supplied to the discharge head, a first degassing unit provided in the first flow path member to remove dissolved gas from the first liquid in the first flow path member, a second degassing unit provided in the second flow path member to remove dissolved gas from the second liquid in the second flow path member, a decompression generator that decompresses the first degassing unit and the second degassing unit, a gas path member that connects the decompression generator, the first degassing unit, and the second degassing unit by branching in the middle of the path, a first restricting member that restricts the movement of the fluid from the branch position toward the first degassing unit is installed in the gas path member closer to the first degassing unit than the branch position, A liquid discharge device in which a second restricting member that restricts the movement of the fluid from the branch position toward the second degassing unit is installed in the gas path member closer to the second degassing unit than the branch position.

2. The liquid discharge device according to claim 1, wherein the decompression generator is provided with a storage unit that stores the liquid contained in the dissolved gas to be sucked.

3. Comprising a notification unit, a sensor for detecting the first liquid or the second liquid is provided in the storage unit, The liquid discharge device according to claim 2, wherein the notification unit notifies of leakage of the first liquid and the second liquid based on the detection result of the sensor.

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