Liquid discharge device

Abstract

To prevent damage and malfunction of members in a liquid discharge device caused due to increase of a pressure in a liquid path caused by a liquid sending mechanism being driven in a state where the liquid path is closed.SOLUTION: A liquid discharge device 1 includes: a sub-tank 105; a main tank 201; a liquid path 220; an air trap tank 205; a liquid sending pump 208 configured to send a liquid; a liquid supply valve 209 provided at the downstream side of the liquid sending pump in the liquid path in a liquid sending direction; a bypass path 230; a three-way valve 231; an exhaust path 211 communicating with the air trap tank 205; and a pressure releasing valve 242 provided at the exhaust path. When supply of electric power to the liquid supply valve is stopped to close the liquid supply valve and the liquid sending pump is driven, supply of electric power to the three-way valve is stopped to open the three-way valve and a pressure in the liquid path is released to the outside by the pressure releasing valve through the bypass path, the air trap tank, and the exhaust path to prevent damage and malfunction of members.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] There have conventionally been liquid ejection devices that include a sub-tank as a first storage section that temporarily stores liquid to be supplied to a liquid ejection head, a main tank as a second storage section that supplies liquid to the sub-tank, and a liquid path that supplies liquid from the main tank to the sub-tank.

[0003] For example, in Patent Document 1 (JP 2023-8531 A), an air trap tank as an air capture member is provided midway through the liquid path, a liquid delivery pump as a liquid delivery mechanism is provided downstream in the liquid delivery direction of the air trap tank, and an on-off valve is provided further downstream of that. When liquid is supplied from the main tank to the sub-tank, the on-off valve is opened by power supply, and the liquid delivery pump is driven to deliver the liquid from the upstream side to the downstream side in the liquid delivery direction. Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid ejection device of Patent Document 1, when the power supply is cut off due to an emergency machine stop or the like while the liquid delivery mechanism is in operation, the on-off valve immediately closes and the liquid path is closed, but the liquid delivery mechanism continues to deliver liquid for a short time by remaining rotation, which causes the pressure in the liquid path to rise, leading to a problem of damage to the liquid path and electromagnetic valves such as the on-off valve.

[0005] An object of the present invention is to prevent damage to members within a liquid ejection device and malfunctions caused by an increase in pressure within the liquid path caused by driving a liquid delivery mechanism with the liquid path closed. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a liquid ejection head including a first storage section for storing liquid and supplying the liquid to a liquid ejection head, a second storage section for storing the liquid and supplying the liquid to the first storage section, a liquid path connecting the first storage section and the second storage section, an air trapping member provided midway through the liquid path, a liquid delivery mechanism provided downstream of the air trapping member in a liquid delivery direction and for delivering the liquid from the second storage section to the first storage section, an on-off valve provided downstream of the liquid delivery mechanism in the liquid path in the liquid delivery direction, a three-way valve provided at a connection point between the bypass path and a position of the liquid path downstream in the liquid delivery direction of the liquid delivery mechanism and upstream of the on-off valve, a pressure relief path communicating with the air capturing member, and a pressure relief valve provided in the pressure relief path, wherein the on-off valve is closed when power is not supplied to the on-off valve and when the liquid delivery mechanism is driven, the three-way valve is opened when power is not supplied to the three-way valve, and pressure in the liquid path is released to the outside by the pressure relief valve via the bypass path, the air capture member, and the pressure relief path. Effect of the Invention

[0007] According to the present invention, the pressure in the liquid path increases when the liquid delivery mechanism is driven with the liquid path closed, and damage or malfunction of members in the liquid ejection device can be prevented. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing an overall configuration of a liquid ejection device according to an embodiment of the present invention; [Diagram 2] FIG. 2 shows a plurality of liquid supply units. [Diagram 3] FIG. 2 is a plan view of a discharge unit included in the liquid discharge device. [Figure 4] FIG. 2 is a side view of a discharge unit included in the liquid discharge device. [Diagram 5] FIG. 2 is a configuration diagram of a liquid supply unit included in the liquid ejection device. [Figure 6] 4 is a block diagram showing a control configuration relating to ink supply of the liquid ejection device. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding parts are given the same reference numerals, and the duplicated description will be appropriately simplified or omitted. In the following description, a liquid ejection device that ejects ink as a liquid will be illustrated as an example of the liquid ejection device of the present invention.

[0010] 1 is a schematic diagram illustrating the overall configuration of a liquid ejection device 1 according to this embodiment. The liquid ejection device 1 includes an input section 10, a printing section 20, a drying section 30, and an output section 40. The liquid ejection device 1 transports paper P as a recording medium from the input section 10 to the printing section 20, where liquid is applied to the paper P to perform a required image formation process (printing process). The liquid ejection device 1 then dries the liquid attached to the paper P in the drying section 30, and then collects the paper P in the output section 40.

[0011] The carry-in section 10 includes an input tray 11, a feeding device 12, and a pair of registration rollers 13. The input tray 11 holds a plurality of sheets of paper P. The feeding device 12 separates the sheets of paper P from the input tray 11 one by one and sends them out toward the pair of registration rollers 13. The pair of registration rollers 13 sends the sheets of paper P into the printing section 20.

[0012] The feeding device 12 may have various configurations, such as a device using rollers or a device using air suction, as long as it is configured to separate the stacked paper P and send it downstream. The pair of registration rollers 13 is driven at a predetermined timing after the leading edge of the paper P has arrived, to transport the paper P.

[0013] The printing unit 20 includes a transport drum 21, which is a first rotating member, and a liquid ejection unit 22. The transport drum 21 carries and transports the paper P on its outer circumferential surface. The liquid ejection unit 22 ejects liquid toward the paper P carried by the transport drum 21.

[0014] The printing unit 20 includes a transfer cylinder 24, which is a second rotating member, and a transfer cylinder 25. The transfer cylinder 24 receives the fed paper P and transfers the paper P to the transport drum 21. The transfer cylinder 25 transfers the paper P transported by the transport drum 21 to the drying unit 30.

[0015] The paper sheet P transported from the carry-in section 10 to the printing section 20 has its leading edge gripped by a second gripping member serving as a sheet gripper, described later, provided on the transfer drum 24, and is transported as the transfer drum 24 rotates. The paper sheet P transported by the transfer drum 24 is delivered to the transport drum 21 at a position opposite the transport drum 21.

[0016] A first gripping member serving as a sheet gripper is also provided on the surface of the transport drum 21, and the leading edge of the paper P is gripped by the first gripping member. A plurality of suction holes are formed and dispersed on the surface of the transport drum 21. A suction device 26 serving as a suction stage generates a suction airflow that flows inward from the suction port of the transport drum 21. The leading edge of the paper P transferred from the transfer drum 24 to the transport drum 21 is gripped by the first gripping member, and the paper P is sucked onto the transport drum 21 by the suction airflow of the suction device 26, and is transported as the transport drum 21 rotates.

[0017] The liquid discharge section 22 includes discharge units 23 (23A to 23F) which are liquid discharge members. For example, the discharge unit 23A discharges cyan (C) liquid, the discharge unit 23B discharges magenta (M) liquid, the discharge unit 23C discharges yellow (Y) liquid, and the discharge unit 23D discharges black (K) liquid. The discharge units 23E and 23F are used to discharge any of YMCK, or special liquids such as white and gold (silver). Furthermore, a discharge unit 23 that discharges a treatment liquid such as a surface coating liquid can also be provided.

[0018] The ejection operation of each ejection unit 23 of the liquid ejection section 22 is controlled by a drive signal corresponding to the printing information. When the paper P supported on the transport drum 21 passes through an area facing the liquid ejection section 22, liquid of each color is ejected from the ejection units 23, and an image corresponding to the printing information is printed. Liquid of a required color is supplied to each ejection unit 23 of the liquid ejection section 22 from liquid supply units 81 (81A to 81D) of the liquid supply section 80, as shown in FIG.

[0019] 1, the drying section 30 includes a drying mechanism section 31 and a suction transport mechanism section 32. The drying mechanism section 31 dries liquid adhering to the paper P in the printing section 20. The suction transport mechanism section 32 transports the paper P transported from the printing section 20 in a suctioned state (suction transports the paper P).

[0020] The paper P transported from the printing unit 20 is received by the suction transport mechanism 32, then transported to pass through the drying mechanism 31 and delivered to the discharge unit 40. When passing through the drying mechanism 31, the liquid on the paper P is dried. This causes the water content in the liquid to evaporate, the colorant contained in the liquid to be fixed on the paper P, and curling of the paper P is suppressed.

[0021] The discharge section 40 includes a discharge tray 41 on which a plurality of sheets of paper P are stacked. The sheets of paper P conveyed from the drying section 30 are successively stacked and held on the discharge tray 41.

[0022] In addition, the liquid ejection device 1 can have, for example, a pre-processing unit that performs pre-processing on the paper P located upstream of the printing unit 20, or a post-processing unit that performs post-processing on the paper P to which liquid has adhered, located between the drying unit 30 and the discharge unit 40.

[0023] An example of the pre-treatment section is a section that performs a pre-coating process in which a treatment liquid that reacts with the liquid to suppress bleeding is applied to the paper P. An example of the post-treatment section is a section that performs a sheet reversing and conveying process in which a sheet printed in the printing section 20 is reversed and sent back to the printing section 20 to print on both sides of the paper P, and a process for binding multiple sheets.

[0024] Next, the configuration of the discharge unit 23 included in the liquid discharge device 1 will be described with reference to Figures 3 and 4. Figure 3 is an explanatory plan view of the discharge unit, and Figure 4 is an explanatory side view of the discharge unit.

[0025] The discharge unit 23 has a plurality of liquid discharge heads 100 arranged in a staggered manner on a head base 52. The plurality of liquid discharge heads 100 are connected to a manifold 103 for distributing liquid arranged above through a supply path 104. Note that a flow-through type head (circulation type head) can also be used as the liquid discharge head 100.

[0026] A subtank 105 is provided upstream of the manifold 103 as a first storage section. The subtank 105 temporarily stores ink to be supplied to the liquid ejection head 100. By creating a negative pressure in the subtank 105, a meniscus pressure is generated in the nozzles of the liquid ejection head 100. Ink of a required color is supplied to the subtank 105 from a liquid supply unit 81 including a main tank via a liquid path 220. The direction of arrow A1 in FIG. 3 is the liquid supply direction to the subtank 105, and the direction of arrow A2 is the backflow direction from the subtank 105.

[0027] The subtank 105 is equipped with a filler 135, a full sensor 107, and a shortage sensor 108. The filler 135 is displaced according to the amount of ink remaining inside the subtank 105. The full sensor 107 detects when the filler 135 is in the full position. The shortage sensor 108 detects when the filler 135 is in the shortage position.

[0028] Next, the liquid supply unit 81 of the liquid supply section 80 will be described with reference to Fig. 5. Fig. 5 shows one of the multiple liquid supply units 81 provided in the liquid supply section 80. Each liquid supply unit 81 in this embodiment has the same configuration except for the type of ink that is ejected. However, the present invention is not limited to this, and each liquid supply unit 81 may have a different configuration.

[0029] As shown in FIG. 5, the liquid supply unit 81 has main tanks 201A, 201B as a second storage section, a liquid path 220, an air trap tank 205 as an air capturing member, an upper limit detection sensor 206a, an appropriate amount detection sensor 206b, and a lower limit detection sensor 206c as liquid level detection members, a liquid delivery pump 208 as a liquid delivery mechanism, a liquid supply valve 209 as an opening / closing valve, an exhaust path 211 as a pressure relief path, an exhaust valve 212, a bypass path 230, a three-way valve 231, a three-way connector 232, an atmospheric release valve 241, a pressure relief valve 242, a degassing section 250, and a foreign object capture filter 253 as a foreign object capture member.

[0030] The liquid path 220 is a path that leads from the main tanks 201A and 201B to the sub tank 105, and is a path that sends the ink 300 from the main tanks 201A and 201B to the sub tank 105. The liquid path 220 has first paths 221A and 221B, a second path 222, a third path 223, and a fourth path 224. The direction of arrow B1 → arrow B2 → arrow B3 → arrow B4 in FIG. 5 is the liquid sending direction of the ink 300 in the liquid path 220. The direction in which the liquid path 220 enters the bypass path 230 midway in the direction of arrow B3 and is sent from arrow C1 to arrow C2 is the bypass direction branching off from the third path 223. The direction of sending from the air trap tank 205 to the arrow D1 by the exhaust path 211 is the exhaust direction.

[0031] The liquid supply unit 81 is provided with detachable main tanks 201A and 201B. The main tanks 201A and 201B are containers for storing the ink 300 to be supplied to the sub tank 105, and the capacity is set to, for example, 10 to 200 liters. One end of the first paths 221A and 221B is connected to the main tanks 201A and 201B, respectively. In the middle of the first paths 221A and 221B, upstream side opening / closing valves 202A and 202B for opening and closing the first paths 221A and 221B are provided, respectively. The other ends of the first paths 221A and 221B are connected to a three-way connector 203. The remaining end of the three-way connector is connected to one end of a second path 222.

[0032] The other end of the second path 222 is connected to the air trap tank 205. The air trap tank 205 is, for example, a sealed container of 0.3 to 1 liter, and is made of a resin having transparency and chemical resistance, such as PE, PP, or PET, or a glass bottle. An upper limit detection sensor 206a, an appropriate amount detection sensor 206b, and a lower limit detection sensor 206c are installed in the air trap tank 205. The upper limit detection sensor 206a detects the upper limit position of the ink 300 in the air trap tank 205. The appropriate amount detection sensor 206b detects the appropriate amount position of the ink 300 in the air trap tank 205. The lower limit detection sensor 206c detects the lower limit position of the ink 300 in the air trap tank 205. For example, an infrared reflective sensor can be used as the upper limit detection sensor 206a, the appropriate amount detection sensor 206b, and the lower limit detection sensor 206c. Alternatively, the liquid level sensor may be configured to have a plurality of electrodes of different lengths, and detect the liquid level by their capacitance.

[0033] One end of an exhaust path 211 is connected to the top of the air trap tank 205. An exhaust valve 212 that opens and closes the exhaust path 211 is provided midway along the exhaust path 211. An exhaust pump 213 serving as an exhaust mechanism is provided downstream of the exhaust valve 212 in the exhaust direction, and is connected to the outside air further downstream. By driving the exhaust pump 213 with either one of the upstream opening / closing valves 202A, 202B and the exhaust valve 212 open, air in the air trap tank 205 can be exhausted to the atmosphere via the exhaust path 211, and ink 300 in the main tank 201A or 201B can be drawn into the air trap tank 205. The same exhaust pump 213 is used across a plurality of liquid supply units 81.

[0034] An atmosphere release valve 241 and a pressure relief valve 242 are provided in the exhaust path 211, upstream of the exhaust valve 212 in the exhaust direction. When the atmosphere release valve 241 or the pressure relief valve 242 is opened, the exhaust path 211 communicates with the atmosphere. The atmosphere release valve 241 is opened after ink 300 has been drawn from the main tanks 201A and 201B into the air trap tank 205, and draws air from the atmosphere into the air trap tank 205. The pressure relief valve 242 is a relief valve that opens when a certain pressure is applied.

[0035] One end of a third path 223 is connected to the bottom of the air trap tank 205. A liquid feed pump 208 and a liquid supply valve 209 are arranged in the third path 223. The liquid supply valve 209 is of a normally closed type that is open when driven and closed when not driven. It is also possible to connect the third path 223 to the top of the air trap tank 205 and extend the third path 223 to the bottom of the air trap tank 205. A non-reversible liquid feed pump such as a diaphragm pump is used as the liquid feed pump 208.

[0036] In the middle of the third path 223, downstream of the liquid feed pump 208, a foreign matter trapping filter 253 and a degassing module 252 using a hollow fiber filter are provided.

[0037] The degassing section 250 has a degassing pump 251 and a degassing module 252. There are cases where the ink 300 in the main tanks 201A and 201B is liquid that has not been degassed. When the ink 300 is discharged from the liquid discharge head, if the degree of degassing in the ink 300 is low, that is, if the dissolved oxygen rate is high, air bubbles are generated in the nozzle, causing non-discharge of ink by the liquid discharge head. In contrast, in this embodiment, the ink 300 sent to the sub tank is degassed by the degassing section 250, thereby preventing non-discharge of ink. Specifically, the ink 300 is degassed by passing it through the degassing module 252 that has been evacuated by the degassing pump 251, thereby reducing the dissolved oxygen rate. In this embodiment, a common degassing pump 251 is used for a plurality of liquid supply units 81.

[0038] A fourth path 224 leading to the sub-tank 105 is provided downstream of the liquid supply valve 209. In this embodiment, two sub-tanks 105 are provided for one liquid supply unit 81, but one, or three or more sub-tanks may be provided. A liquid supply valve 209 is provided between the fourth path 224 leading to each sub-tank 105 and the third path 223, allowing liquid supply control to each sub-tank 105 individually.

[0039] A three-way valve 231 is provided in the middle of the third path 223, downstream in the liquid sending direction of the liquid sending pump 208 and upstream of the liquid supply valve 209. The three-way valve 231 connects a position in the middle of the third path 223 to the other end of the bypass path 230. One end of the bypass path 230 is connected to the middle of the second path 222 by a three-way connector 232. In other words, the bypass path 230 is a path that connects the upstream side of the air trap tank 205 in the liquid sending direction of the liquid path 220 to the downstream side of the liquid sending pump 208 and upstream side of the liquid supply valve 209. In addition, the valve that connects the other end of the bypass path 230 to a position downstream of the liquid sending pump 208 and upstream of the liquid supply valve 209 is called a three-way valve because the path to be connected is three-way, but it does not necessarily mean only a valve connected in three ways, and may be a valve connected to a path in four or more ways.

[0040] As shown in FIG. 6, the liquid ejection device has a control unit 260. The upstream opening / closing valves 202A and 202B, the liquid supply valve 209, the three-way valve 231, and the atmosphere release valve 241 are solenoid valves, which are supplied with power and controlled by the control unit 260 to switch between open and closed states. The control unit 260 drives and controls the liquid feed pump 208, the exhaust pump 213, and the degassing pump 251. The control unit 260 receives detection information from the upper limit detection sensor 206a, the appropriate amount detection sensor 206b, and the lower limit detection sensor 206c. Based on the detection results, the control unit 260 switches the open and closed states of the upstream opening / closing valves 202A and 202B, and controls the operation of sending ink 300 from the main tanks 201A and 201B to the air trap tank 205. The liquid ejection device also has a power supply unit that receives power from an external power source. The power supply unit supplies power to the control unit 260, the sensors in FIG. 6, the pumps, and the solenoid valves.

[0041] Next, the operation of the liquid supply unit 81 during printing, particularly the operation of sending ink 300 from either the main tank 201A or 201B to the air trap tank 205, will be described.

[0042] 5, when either the upstream opening / closing valve 202A, 202B is opened and the exhaust valve 212 is closed, the inside of the air trap tank 205 is sealed. When the liquid feed pump 208 is driven in this state, the ink 300 in either the main tank 201A, 201B is drawn into the air trap tank 205, and the ink 300 in the air trap tank 205 is sent to the downstream side of the liquid path 220 and supplied to the sub-tank 105. This maintains a state in which a constant amount of ink 300 is contained in the air trap tank 205.

[0043] As printing progresses and the ink 300 in the main tank 201A or 201B runs out, the ink 300 in the air trap tank 205 decreases, and the lower limit detection sensor 206c detects that the ink 300 has fallen below the lower limit.

[0044] Next, the operation of the air trap tank 205 when the ink 300 is supplied from the main tank 201A will be described.

[0045] When the ink 300 in the air trap tank 205 decreases and, for example, the lower limit detection sensor 206c detects that the ink has fallen below the lower limit, the control unit opens the exhaust valve 212 and drives the exhaust pump 213 to draw the ink 300 from the main tank 201A into the air trap tank 205. At this time, if the amount of ink 300 in the air trap tank 205 does not recover even after a predetermined time, for example, 1 to 120 seconds, has elapsed, the control unit determines that the main tank 201A has reached an end state.

[0046] When the control unit determines that the main tank 201A has reached the end state, it closes the upstream opening / closing valve 202A and opens the upstream opening / closing valve 202B. This causes ink 300 to be drawn from the main tank 201B into the air trap tank 205, and the ink in the air trap tank 205 is restored to a position detected by the appropriate amount detection sensor 206b.

[0047] By providing an air trap tank 205 in the middle of the liquid path 220 that sends ink 300 from the main tanks 201A, 201B to the sub tank 105, the ink 300 and air can be separated in the air trap tank 205, and air can be prevented from being sent to, for example, the liquid feed pump 208 downstream of the air trap tank 205 in the liquid feed direction.

[0048] Next, the operation of sending the ink 300 from the main tank 201A to the sub tank 105 will be described.

[0049] When sending ink 300 from the main tank 201A to the sub tank 105, the control unit opens the upstream opening / closing valve 202A and closes the upstream opening / closing valve 202B. Then, when the appropriate amount detection sensor 206b is in a detection state, the control unit closes the exhaust valve 212. In this state, the liquid supply valve 209 is repeatedly opened and closed depending on the amount of ink 300 in the sub tank 105, that is, depending on the position of the filler in the sub tank 105. As a result, when the liquid feed pump 208 is driven, the ink 300 in the main tank 201A is sent to the sub tank 105.

[0050] Next, an operation when the power supply to the liquid ejection device is stopped due to an abnormality will be described.

[0051] During the operation of sending ink 300 from either of the main tanks 201A and 201B to the subtank 105, the power supply to the liquid ejection device may suddenly stop due to a power outage, a momentary power outage, pressing of an emergency stop button, etc., and power may no longer be supplied to the liquid supply valve 209 and the like. In this case, the liquid supply valve 209 is immediately closed when the power supply is stopped, whereas there is a time lag between the power supply being stopped and the liquid supply pump 208 stopping the rotation of the motor. In other words, with the liquid supply valve 209 closed and the downstream side of the liquid path 220 closed, the liquid supply pump 208 sends the ink 300 downstream in the liquid sending direction. If the pressure rise in the liquid path 220 caused by this cannot be released, the liquid path 220 may be damaged, or the solenoid valve such as the liquid supply valve 209 may malfunction due to the pressure exceeding the operating pressure range of the solenoid valve.

[0052] In contrast, in this embodiment, the pressure relief valve 242 can release the pressure in the liquid path 220 to the outside. Specifically, the three-way valve 231 provided in the middle of the third path 223 is in a closed state when the ink 300 is supplied to the sub tank 105, but is in an open state when the power supply is stopped. When the three-way valve 231 is opened, the third path 223 is in a state of communication with the bypass path 230. As a result, the pressure increased in the third path 223 is released to the bypass path 230 side and sent to the air trap tank 205. Then, the pressure in the section of the air trap tank 205 and the exhaust path 211 up to the exhaust valve 212 increases. Then, when the pressure in the section of the exhaust path 211 up to the exhaust valve 212 exceeds a predetermined value, the pressure relief valve 242 opens and the exhaust path 211 is in communication with the atmosphere. As a result, the pressure increase occurring in the third path 223 can be released to the outside. Furthermore, at this time, by passing through the air trap tank 205, the ink 300 sent out by the liquid feed pump 208 can be stored in the air trap tank 205, and the ink 300 is not discharged to the outside at the same time as the pressure is released from the pressure relief valve 242. In other words, it is possible to prevent the ink 300 from being wasted. In this way, the portion of the exhaust path 211 from the air trap tank 205 to the pressure relief valve 242 is a pressure relief path for releasing pressure from the air trap tank 205 to the outside.

[0053] As described above, according to this embodiment, even if the liquid feed pump 208 is driven in a state in which the liquid path 220 is closed due to a power outage, the resulting pressure increase can be released to the outside via the bypass path 230, the second path 222, the air trap tank 205, the exhaust path 211, and the pressure relief valve 242. This makes it possible to prevent damage to the liquid path 220 and malfunction of the liquid supply valve 209.

[0054] Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0055] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited, but it is preferable that the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural colorant, etc., and these can be used for applications such as inkjet ink, surface treatment liquid, a liquid for forming a component of an electronic element or a light-emitting element, an electronic circuit resist pattern, a material liquid for three-dimensional modeling, etc.

[0056] "Liquid" includes not only ink but also paint, pretreatment liquid, binder, and overcoat liquid.

[0057] In this application, a "liquid ejection device" is a device that includes a carriage having a liquid ejection head and ejects liquid by driving the liquid ejection head. Liquid ejection devices include not only devices that can eject liquid onto a recording medium to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0058] This "liquid ejection device" can also include means for feeding, transporting, and discharging objects onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0059] For example, examples of "liquid ejection devices" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0060] Furthermore, the term "liquid ejection device" is not limited to devices that visualize meaningful images such as characters and figures by ejecting liquid. For example, the term also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0061] The above-mentioned "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, cloth, and other recording media, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

[0062] The material of the above-mentioned "object to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics.

[0063] Other examples of "liquid ejection devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0064] In the present application, the terms image formation, recording, printing, imprinting, printing, modeling, and the like are all synonymous.

[0065] For example, aspects of the present invention are as follows. <1> a first reservoir that stores liquid and supplies the liquid to a liquid ejection head; a second storage section configured to store the liquid and supply the liquid to the first storage section; a liquid path connecting the first storage portion and the second storage portion; an air capture member provided midway through the liquid path; a liquid sending mechanism provided downstream of the air capturing member in a liquid sending direction and configured to send the liquid from the second storage portion to the first storage portion; an on-off valve provided on the liquid path downstream of the liquid sending mechanism in a liquid sending direction; a bypass path that connects a side of the liquid path downstream of the liquid delivery mechanism in a liquid delivery direction and upstream of the on-off valve to a side of the liquid path upstream of the air capture member; a three-way valve provided at a connection point between the bypass path and the liquid path at a position downstream of the liquid delivery mechanism in a liquid delivery direction and upstream of the on-off valve; a pressure relief path communicating with the air trapping member; a pressure relief valve provided in the pressure relief path, a pressure relief valve that releases pressure from within the liquid path to the outside via the bypass path, the air capture member, and the pressure relief path when the three-way valve is opened when power is not supplied to the three-way valve and when the liquid delivery mechanism is driven, the pressure relief valve releases pressure from within the liquid path to the outside via the bypass path, the air capture member, and the pressure relief path. <2> a degassing unit that is provided downstream of the liquid sending mechanism in the liquid sending direction of the liquid path and that degasses the liquid in the liquid path; <1> The liquid ejection apparatus is as described above. <3> The second storage section; The liquid path; The air trapping member; The liquid delivery mechanism; The on-off valve; The bypass path; The three-way valve; The pressure relief path; The pressure relief valve is provided in a plurality of liquid supply units. <2> The liquid ejection device according to the present invention comprises: The degassing unit has a degassing pump, The liquid ejection apparatus includes a degassing pump common to a plurality of the liquid supply units. <4> a foreign object capturing member that is provided on the liquid path downstream of the liquid sending mechanism in a liquid sending direction and that captures foreign objects in the liquid in the liquid path; <1> from <3> The liquid ejection apparatus according to any one of the above aspects is provided. <5> The second storage section; The liquid path; The air trapping member; The liquid delivery mechanism; The on-off valve; The bypass path; The three-way valve; The pressure relief path; The pressure relief valve is provided in a plurality of liquid supply units. <1> from <4> In any one of the liquid ejection devices, an exhaust mechanism for discharging the air captured by the air capturing member to the outside; The exhaust mechanism is common to the plurality of liquid supply units. <6> A plurality of the second storage sections; The liquid path; The air trapping member; The liquid delivery mechanism; The on-off valve; The bypass path; The three-way valve; The pressure relief path; and a liquid supply unit having the pressure relief valve. <1> from <5> The liquid ejection apparatus according to any one of the above aspects is provided. [Explanation of symbols]

[0066] 1 Liquid discharge device 80 Liquid discharge part 81 Liquid supply unit 105 Subtank (First storage section) 201A, 201B main tank 205 Air trap tank (air capture component) 208 Liquid delivery pump (liquid delivery mechanism) 209 Liquid supply valve (on-off valve) 211 Exhaust route (pressure relief route) 213 Exhaust pump (exhaust mechanism) 220 Liquid Path 230 Bypass Route 231 Three-way valve 250 Deaeration section 251 Degassing Pump 253 Foreign object capture filter (foreign object capture member) 260 Power supply section 300 Ink (liquid) B1, B2, B3, B4 Flow direction [Prior art documents] [Patent documents]

[0067] [Patent Document 1] JP 2023-8531 A

Claims

1. a first reservoir configured to store liquid and supply the liquid to a liquid ejection head; a second storage section configured to store the liquid and supply the liquid to the first storage section; a liquid path connecting the first storage portion and the second storage portion; an air capture member provided midway through the liquid path; a liquid sending mechanism provided downstream of the air capturing member in a liquid sending direction and configured to send the liquid from the second storage portion to the first storage portion; an on-off valve provided on the liquid path downstream of the liquid sending mechanism in a liquid sending direction; a bypass path that connects a side of the liquid path downstream of the liquid delivery mechanism in a liquid delivery direction and upstream of the on-off valve to a side of the liquid path upstream of the air capture member; a three-way valve provided at a connection point between the bypass path and the liquid path at a position downstream of the liquid delivery mechanism in a liquid delivery direction and upstream of the on-off valve; a pressure relief path communicating with the air trapping member; a pressure relief valve provided in the pressure relief path, a pressure relief valve that releases pressure from within the liquid path to the outside via the bypass path, the air capture member, and the pressure relief path when the three-way valve is opened when power is not supplied to the three-way valve and when the liquid delivery mechanism is driven, the pressure relief valve releases pressure from within the liquid path to the outside via the bypass path, the air capture member, and the pressure relief path.

2. The liquid ejection device according to claim 1 , further comprising a degassing section provided on the liquid path downstream in the liquid sending direction from the liquid sending mechanism, for degassing the liquid in the liquid path.

3. The second storage section; The liquid path; The air trapping member; The liquid delivery mechanism; The on-off valve; The bypass path; The three-way valve; The pressure relief path; 3. The liquid ejection apparatus according to claim 2, further comprising a plurality of liquid supply units each having the pressure relief valve, The degassing unit has a degassing pump, The liquid ejection apparatus, wherein the degassing pump is common to a plurality of the liquid supply units.

4. 2. The liquid ejection device according to claim 1, further comprising a foreign matter capturing member provided on the liquid path downstream in the liquid transport direction from the liquid transport mechanism, the foreign matter capturing member capturing foreign matter in the liquid in the liquid path.

5. The second storage section; The liquid path; The air trapping member; The liquid delivery mechanism; The on-off valve; The bypass path; The three-way valve; The pressure relief path; 2. The liquid ejection apparatus according to claim 1, further comprising a plurality of liquid supply units each having the pressure relief valve, an exhaust mechanism for discharging the air captured by the air capturing member to the outside; The liquid ejection apparatus, wherein the exhaust mechanism is common to a plurality of the liquid supply units.

6. A plurality of the second storage sections; The liquid path; The air trapping member; The liquid delivery mechanism; The on-off valve; The bypass path; The three-way valve; The pressure relief path; 2. The liquid ejection device according to claim 1, further comprising a liquid supply unit having the pressure relief valve.

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