Liquid jet head

Abstract

To provide a structure for efficiently supplying liquid to a nozzle and efficiently ejecting the liquid from the nozzle. [Solution] The liquid jet head includes a plurality of nozzles that eject liquid, pressure chambers that communicate with the nozzles and apply pressure to the liquid, a common liquid chamber that communicates with the plurality of nozzles, and a supply flow path that connects the common liquid chamber to the pressure chambers and supplies liquid to the pressure chambers. The supply flow path has a main flow path and a first sub-flow path that connects a first position of the main flow path to a second position of the main flow path that is farther from the pressure chambers than the first position. The first sub-flow path has a first portion that extends from the first position in a first direction and a second portion that extends from the second position in a second direction. At the first position, the angle formed by the direction of liquid flow through the main flow path toward the pressure chambers and the first direction is an obtuse angle, and at the second position, the angle formed by the direction of liquid flow through the main flow path toward the pressure chambers and the second direction is an obtuse angle.

Description

[Technical Field]

[0001] The present disclosure relates to a liquid jet head. [Background technology]

[0002] Patent Document 1 discloses a liquid jet head that uses pressure chambers to jet liquid from nozzles. It discloses that in this liquid jet head, the width of a communication channel between a liquid storage chamber and a pressure chamber is smaller than the width of the pressure chamber. With this configuration, the channel resistance of the communication channel is greater than the channel resistance of the pressure chamber, so the communication channel functions as a throttle channel to prevent ink from flowing back from the pressure chamber to the liquid storage chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-179579 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, the presence of a throttled flow path prevents the pressure generated in the liquid in the pressure chamber by the drive element from escaping to the liquid storage chamber via the communicating flow path, thereby improving ejection efficiency. Therefore, while it is conceivable to further improve ejection efficiency by increasing the resistance of the throttled flow path, this increases the problem of making it more difficult to supply liquid from the liquid storage chamber to the pressure chamber. Therefore, it is desirable to improve ejection efficiency while preventing a decrease in the ability to supply liquid to the pressure chamber. [Means for solving the problem]

[0005] A liquid jet head according to a first aspect of the present disclosure includes a plurality of nozzles that eject liquid, pressure chambers that communicate with the nozzles and apply pressure to the liquid, a common liquid chamber that communicates with the plurality of nozzles, and a supply flow path that connects the common liquid chamber to the pressure chambers and supplies the liquid to the pressure chambers. The supply flow path has a main flow path and a first sub-flow path that connects a first position of the main flow path to a second position of the main flow path that is farther from the pressure chambers than the first position. The first sub-flow path has a first portion that extends from the first position in a first direction and a second portion that extends from the second position in a second direction. At the first position, the angle formed between the direction of flow of the liquid through the main flow path toward the pressure chambers and the first direction is an obtuse angle, and at the second position, the angle formed between the direction of flow of the liquid through the main flow path toward the pressure chambers and the second direction is an obtuse angle.

[0006] A liquid jet head according to a second aspect of the present disclosure includes a plurality of nozzles for ejecting liquid, pressure chambers communicating with the nozzles and applying pressure to the liquid, a common liquid chamber communicating with the plurality of nozzles, and a supply flow path connecting the common liquid chamber and the pressure chambers and supplying the liquid to the pressure chambers. The supply flow path includes a main flow path and a sub-flow path connecting a first position of the main flow path to a second position of the main flow path different from the first position. When a flow direction from the main flow path toward the pressure chambers is defined as a forward direction and a flow direction from the pressure chambers toward the main flow path is defined as a reverse direction, when a flow of the liquid in the reverse direction occurs in the main flow path, the sub-flow path converts the flow of the liquid that branches off from the main flow path to the sub-flow path at the first position so that the liquid flows in the main flow path in the forward direction and merges with the main flow path at the second position. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram illustrating a configuration of a liquid ejecting apparatus according to an embodiment. [Figure 2] FIG. 2 is a bottom view of the liquid jet head according to the first embodiment. [Figure 3] FIG. 1 is a cross-sectional view of a liquid jet head according to a first embodiment. [Figure 4]FIG. 2 is a diagram showing a part of a flow path when the liquid jet head according to the first embodiment is viewed from the bottom. [Figure 5] FIG. 3 is an enlarged view showing flow paths for individual nozzles in the first embodiment. [Figure 6] FIG. [Figure 7] 5A and 5B are diagrams showing the flow of liquid when the liquid is supplied and when the liquid is ejected. [Figure 8] FIG. 10 is a diagram showing another example of a backflow prevention unit. [Figure 9] FIG. 4 is an enlarged view of a backflow prevention unit having two sub-flow paths. [Figure 10] FIG. 10 is a cross-sectional view of a liquid jet head according to a second embodiment. [Figure 11] FIG. 10 is an enlarged view of a backflow prevention section according to a second embodiment. [Figure 12] FIG. 10 is a diagram showing another example of a flow path including a backflow suppression unit in the second embodiment. [Figure 13] FIG. 10 is a cross-sectional view of a liquid jet head according to a third embodiment. [Figure 14] FIG. 11 is a diagram illustrating a part of a flow path when a liquid jet head according to a third embodiment is viewed from the bottom. [Figure 15] FIG. 11 is a diagram showing a part of a nozzle-specific flow path in the third embodiment. [Figure 16] FIG. 11 is a diagram showing another example of a flow path for each nozzle in the third embodiment. [Figure 17] FIG. 10 is a cross-sectional view of a liquid jet head according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is an explanatory diagram showing the configuration of a liquid ejection device 400 according to an embodiment. The liquid ejection device 400 is an inkjet printing device that ejects ink, which is an example of a liquid, onto a medium PM. A liquid storage unit 420 that stores ink can be attached to the liquid ejection device 400. The liquid ejection device 400 performs printing by ejecting the ink in the liquid storage unit 420 toward the medium PM. The liquid ejection device 400 includes a liquid ejection head 101, a movement mechanism 430, a transport mechanism 440, a control unit 450, and an input reception unit 460.

[0009] The liquid ejection head 101 includes a plurality of nozzles 200, and ejects liquid ink supplied from a liquid storage unit 420 from the plurality of nozzles 200. Specific examples of the liquid storage unit 420 include a cartridge that is detachable from the liquid ejection device 400, a bag-shaped ink pack made of flexible film, and a container such as an ink tank that can be refilled with ink. The ink ejected from the nozzles 200 lands on a medium PM, which is typically printing paper. Note that the medium M is not limited to printing paper, and may be a printing target made of any material, such as a resin film or fabric.

[0010] The composition of the ink is not particularly limited, and may be, for example, an aqueous ink in which a coloring material such as a dye or pigment is dissolved in an aqueous solvent, a solvent-based ink in which a coloring material is dissolved in an organic solvent, or an ultraviolet-curable ink. The liquid ejection device 400 may also eject other types of liquid, such as paint, instead of ink. The liquid ejection head 101 of this embodiment is capable of ejecting a highly viscous liquid with a viscosity of 20 mPa·s or higher.

[0011] The movement mechanism 430 includes a loop-shaped belt 432 and a carriage 434 fixed to the belt 432. The carriage 434 holds the liquid ejection head 101. The movement mechanism 430 rotates the loop-shaped belt 432 in both directions, thereby causing the liquid ejection head 101 to reciprocate along the X direction.

[0012] The transport mechanism 440 transports the medium PM along the Y direction between movements of the liquid jet head 101 by the movement mechanism 430. The Y direction is a direction perpendicular to the X direction. In this embodiment, the X and Y directions are horizontal. The Z direction is a direction intersecting the X and Y directions. In this embodiment, the Z direction is a vertically downward direction. The liquid jet head 101 ejects liquid along the Z direction while being transported along the X direction. The Z direction is also referred to as the "ejection direction." In the following description, the tip side of an arrow indicating the X direction in the figure is referred to as the +X side, and the base end side is referred to as the -X side. The tip side of an arrow indicating the Y direction in the figure is referred to as the +Y side and the base end side is referred to as the -Y side. The tip side of an arrow indicating the Z direction in the figure is referred to as the +Z side and the base end side is referred to as the -Z side.

[0013] The control unit 450 controls the liquid ejection operation from the liquid ejection head 101. The control unit 450 controls the transport mechanism 440, the movement mechanism 430, and the liquid ejection head 101 to form an image on the medium PM.

[0014] The input receiving unit 460 includes an input unit 461 and an output unit 462. The input unit 461 receives instructions from the user for various settings, such as instructions to execute printing, settings for the gap between the nozzles 200 of the liquid ejection head 101 and the medium PM, and settings for the liquid ejection mode. The output unit 462 displays setting screens for various functions that can be executed by the liquid ejection device 400. In this embodiment, the input receiving unit 460 is an operation panel, and is connected to the control unit 450 so as to be able to send and receive data thereto. The input receiving unit 460 may also be an external computer.

[0015] FIG. 2 is a bottom view of the liquid jet head 101. The liquid jet head 101 has a plurality of nozzles 200. The plurality of nozzles 200 are formed to penetrate a nozzle plate 240 arranged parallel to the XY plane. The plurality of nozzles 200 constitute two nozzle rows NL1 and NL2 arranged linearly along the Y direction. The nozzle plate 240 is manufactured by processing a silicon single crystal substrate using, for example, semiconductor processing technology. As the silicon single crystal substrate, for example, a (100) silicon single crystal substrate is suitably used. The nozzle plate 240 may also be formed from a material such as stainless steel (SUS) or titanium.

[0016] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a diagram illustrating a portion of a flow path as viewed from the bottom of FIG. 3. The liquid jet head 101 has a common liquid chamber 110 to which liquid is supplied from the outside, and nozzle-specific flow paths 120 that connect the common liquid chamber 110 to each of the nozzles 200. The common liquid chamber 110 is provided in common to the plurality of nozzles 200 that constitute one nozzle row. That is, the common liquid chamber 110 temporarily stores liquid supplied from a liquid storage section 420 and supplies the liquid to the plurality of nozzle-specific flow paths 120 that are individually connected to the plurality of nozzles 200. Point P110 shown in FIG. 3 is the end point of the common liquid chamber 110. The flow path from this point P110 to the nozzle 200 is the nozzle-specific flow path 120. In FIG. 3, the nozzle-specific flow paths 120 connected to the nozzles 200 of the first nozzle row NL1 and the nozzle-specific flow paths 120 connected to the nozzles 200 of the second nozzle row NL2 have the same structure.

[0017] The nozzle-specific flow path 120 has a pressure chamber 330 that applies pressure to the liquid, a supply flow path 320 that connects the common liquid chamber 110 and the pressure chamber 330 and supplies liquid to the pressure chamber 330, and a communication path 340 that connects the pressure chamber 330 and the nozzle 200. A drive element 301 that drives the pressure chamber 330 is installed in the pressure chamber 330.

[0018] The pressure chamber 330 extends in the X direction and is provided between the nozzle 200 and the common liquid chamber 110. The pressure chamber 330 is a space that is subject to pressure changes caused by the drive element 301. In FIG. 4, the pressure chamber 330 is depicted by dashed lines and hatched. The multiple pressure chambers 330 are arranged along the Y direction. Therefore, the Y direction is also referred to as the "arrangement direction of the pressure chambers 330." In this embodiment, one pressure chamber 330 is provided for one nozzle 200, but multiple pressure chambers 330 may be provided for one nozzle 200.

[0019] The supply flow path 320 is a flow path that connects the common liquid chamber 110 and the pressure chamber 330. The supply flow path 320 includes a first portion 320P1 that extends in the X direction adjacent to the pressure chamber 330, and a second portion 320P2 that extends in the Z direction from an end of the first portion 320P1 to reach the common liquid chamber 110. The second portion 320P2 is formed so as to penetrate the communication plate 140 and reach the pressure chamber substrate 250. In FIG. 4, the second portion 320P2 is hatched. A part of the first portion 320P1 and the second portion 320P2 are also referred to as the "main flow path 510."

[0020] The communication passage 340 is a flow path that connects the pressure chamber 330 and the nozzle 200. The communication passage 340 extends in the Z direction and passes through the communication plate 140. In Figure 4, the communication passage 340 is indicated by a dotted line.

[0021] As shown in FIG. 3 , a portion of the common liquid chamber 110 and the multiple nozzle-specific flow paths 120 are primarily formed by a communication plate 140 and a pressure chamber substrate 250. A housing 160 and a pressure chamber substrate 250 are disposed on the upper surface of the communication plate 140. The pressure chamber substrate 250 is located inside the housing 160 in a plan view in the Z direction. A vibration plate 310 is disposed on the upper surface of the pressure chamber substrate 250. A pressure chamber 330 is a space defined by the communication plate 140, the vibration plate 310, and the pressure chamber substrate 250. Furthermore, when viewed in the Z direction, the pressure chamber 330 is a region that overlaps with a portion of the vibration plate 310 that is displaced when the drive element 301 is driven. The pressure chamber substrate 250 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor processing technology. A silicon single crystal substrate having a (110) plane as its main surface is preferably used as the silicon single crystal substrate. The communication plates 140 are stacked in a stacking direction perpendicular to the surface of the pressure chamber substrate 250 .

[0022] A nozzle plate 240 is installed on the lower surface of the communication plate 140. The lower end of the common liquid chamber 110 is sealed with a flexible sealing film 150 made of a resin film, a thin metal film, or the like.

[0023] A wiring board 59 is bonded to the upper surface of the vibration plate 310. The wiring board 59 is a mounting component on which a plurality of wires are formed for electrically connecting the control unit 450 and the liquid ejection head 101. A drive circuit 70 for driving the drive elements 301 is mounted on the wiring board 59. The drive circuit 70 supplies a drive signal to the drive elements 301. The drive elements 301 are configured by, for example, piezoelectric elements. When the drive elements 301, which are piezoelectric elements, vibrate, the vibrations are transmitted to the pressure chambers 330, respectively, and pressure fluctuations occur in the pressure chambers 330. The liquid is ejected from the nozzles 200 by the pressure generated by the drive elements 301. Note that instead of piezoelectric elements, heating elements that heat the liquid in the pressure chambers 330 to generate pressure fluctuations in the pressure chambers 330 may be used as the drive elements.

[0024] 5 is an enlarged view of the individual nozzle flow path 120. A backflow suppression section 500 is provided in the first portion 320P1 of the supply flow path 320. The backflow suppression section 500 is formed in the pressure chamber substrate 250, and can be formed, for example, by etching a single silicon substrate.

[0025] In this embodiment, one pressure chamber 330 is provided for one nozzle 200, but multiple pressure chambers 330 may be provided for one nozzle 200. In this case, multiple supply flow paths are provided that respectively connect each pressure chamber 330 to the nozzle 200. Furthermore, a backflow suppression unit 500 is provided in each supply flow path.

[0026] 6 is an enlarged view of the backflow prevention unit 500. The backflow prevention unit 500 has a portion of the main channel 510 and a sub-channel 520 branching off from the main channel 510. The portion of the main channel is a portion of the main channel 510 from a first position P1 to a second position P2. The sub-channel 520 is configured to connect the first position P1 of the main channel 510 to a second position P2 of the main channel 510 that is farther from the pressure chamber 330 than the first position P1. The sub-channel 520 includes a first portion 521 extending from the first position P1 in a first direction D1, a second portion 522 extending from the second position P2 in a second direction D2, and a curved portion 523 (see FIG. 5) connecting the first portion 521 and the second portion 522. An island-shaped portion 524 (see FIG. 5) is formed in the center of the sub-channel 520, and the fluid flowing through the sub-channel 520 flows in a detour around the island-shaped portion 524. The sub-channel 520 is also called a "loop-shaped channel."

[0027] At the first position P1, the angle α between the first direction D1 and a first supply direction Ds1, which is the direction in which the liquid flows through the main channel 510 toward the pressure chamber 330, is an obtuse angle. This angle α is the angle between the direction vector of the first supply direction Ds1 and the direction vector of the first direction D1, and is an angle defined in the range of 0 degrees to 180 degrees. At the second position P2, the angle β between the second direction D2 and a second supply direction Ds2, which is the direction in which the liquid flows through the main channel 510 toward the pressure chamber 330, is an obtuse angle. This angle β is the angle between the direction vector of the second supply direction Ds2 and the direction vector of the second direction D2, and is an angle defined in the range of 0 degrees to 180 degrees. Each of the first supply direction Ds1 and the second supply direction Ds2 can be considered to be parallel to the center line of the main channel 510 of the backflow suppression unit 500. 6, the first supply direction Ds1 and the second supply direction Ds2 are the same because the main flow path 510 of the backflow suppression unit 500 has a linear shape. If the main flow path 510 of the backflow suppression unit 500 has a curved shape, the first supply direction Ds1 and the second supply direction Ds2 will be different directions.

[0028] The entire sub-channel 520 is inclined so that the curved portion 523 is farther from the nozzle 200 than the first portion 521 and the second portion 522. The angle θ1 (=180°-α) formed between the first direction D1 in which the first portion 521 extends and the direction opposite to the first supply direction Ds1 is an acute angle. This angle θ1 is preferably 45 degrees or less, more preferably 30 degrees or less, and most preferably 29 degrees. This allows for clear differences in flow path resistance depending on the direction of liquid flow. A smaller angle θ1 is more preferable, but setting the angle θ1 to an excessively small value may reduce strength. In consideration of this point, the angle θ1 is preferably 10 degrees or more.

[0029] The angle θ2 (=180°-β) formed by the second direction D2 in which the second portion 522 extends and the direction opposite to the second supply direction Ds2 is also an acute angle. This angle θ2 is also preferably equal to or less than 45 degrees, more preferably equal to or less than 30 degrees, and most preferably equal to or less than 29 degrees.

[0030] The two angles θ1 and θ2 may be different values ​​or may be the same value, but if the two angles θ1 and θ2 are different values, the tip of the island-shaped portion 524 at angle θ1 may become excessively sharper than the other tip portions of the island-shaped portion 524, which may reduce the strength of the tip.

[0031] The Y-direction width W500 of the backflow suppression unit 500 is preferably equal to or less than the Y-direction width W330 of the pressure chamber 330. Furthermore, it is preferable that the straight lines 500L1 and 500L2 passing through both ends of the Y-direction of the backflow suppression unit 500 fall within the region between the straight lines 330L1 and 300L2 passing through both ends of the Y-direction of the pressure chamber 330. This prevents the provision of the backflow suppression unit 500 from increasing the size of the head.

[0032] The backflow suppression portion 500 is preferably configured to have a straight line shape, which allows the backflow suppression portion 500 to be easily formed by etching.

[0033] FIG. 7 is a diagram showing the flow of liquid during liquid supply and liquid ejection. During liquid supply, the pressure chamber 330 does not generate pressure, and liquid is supplied from the common liquid chamber 110 toward the nozzle 200. During liquid ejection, pressure is generated in the pressure chamber 330, and liquid is ejected from the nozzle 200 in response to this pressure. The direction in which liquid flows within the supply flow channel 320 from the common liquid chamber 110 toward the pressure chamber 330 is called the "forward flow," and the direction in which liquid flows within the supply flow channel 320 from the pressure chamber 330 toward the common liquid chamber 110 is called the "backflow." The flow of liquid in the backflow suppression unit 500 during liquid supply is a forward flow, and the flow of liquid in the backflow suppression unit 500 during liquid ejection is a backflow.

[0034] The backflow suppression unit 500 has the following characteristics. When liquid is supplied to the pressure chamber 330, the pressure chamber 330 is depressurized, and the liquid flows forward from the common liquid chamber 110 to the pressure chamber 330. On the other hand, when liquid is ejected from the nozzle 200, the pressure chamber 330 is pressurized, and some of the liquid flows from the pressure chamber 330 to the nozzle 200, and some of the liquid flows backward from the pressure chamber 330 toward the common liquid chamber 110. The first direction D1 shown in FIG. 6 is the direction in which the liquid branches off from the first position P1 to the sub-channel 520 during backward flow, and the second direction D2 is the direction in which the liquid branches off from the second position P2 to the sub-channel 520 during forward flow. Details of the flow during forward flow and backward flow are as follows.

[0035] <During forward flow> When liquid is supplied, and the liquid flows forward from the common liquid chamber 110 to the pressure chamber 330, the overall flow of the liquid is divided into a flow that flows through the main channel 510 and a flow that branches off from the main channel 510 to the sub-channel 520 at a second position P2 and then joins the main channel 510 at a first position P1. At the second position P2, the angle β formed by the flow in the main channel 510 and the flow that branches off to the sub-channel 520 is an obtuse angle, so the liquid is unlikely to flow into the sub-channel 520. Even if the liquid does flow into the sub-channel 520, the angle θ1 formed by the flow joining the main channel 510 and the flow in the main channel 510 at the first position P1 is an acute angle, so the flow joining the main channel 510 does not interfere with the flow in the main channel 510 and is unlikely to act as resistance to the flow in the main channel 510.

[0036] <When reflux occurs> When liquid flows back toward the common liquid chamber 110 during liquid ejection, the overall flow of the liquid is divided into a flow that flows through the main channel 510 and a flow that branches off from the main channel 510 to the sub-channel 520 at a first position P1 and then joins the main channel 510 at a second position P2. At the first position P1, the angle θ1 formed between the flow in the main channel 510 and the flow that branches off to the sub-channel 520 is an acute angle, so the liquid easily flows into the sub-channel 520. At the second position P2, the angle β = (180 - θ2) formed between the flow joining the main channel 510 and the flow in the main channel 510 is an obtuse angle, so the flow joining the main channel 510 collides with the flow in the main channel 510 and acts as resistance to the flow in the main channel 510.

[0037] The flow direction from the main channel 510 to the pressure chamber 330 is defined as the forward direction, and the flow direction from the pressure chamber 330 to the main channel 510 is defined as the reverse direction. In this case, when a reverse flow of liquid occurs in the main channel 510, the sub-channel 520 converts the liquid flow so that the liquid branched from the main channel 510 to the sub-channel 520 at the first position P1 flows forward through the main channel 510 and merges with the main channel 510 at the second position P2. Therefore, the backflow suppression unit 500 has a higher flow resistance for a reverse flow than for a forward flow, and can effectively suppress a backflow without narrowing the flow channel diameter too much. As a result, it is possible to reduce the backflow of liquid from the pressure chamber 330 without interfering with the supply of liquid. By reducing the backflow, it is possible to increase the amount of liquid flowing from the pressure chamber 330 to the nozzle 200 during ejection, thereby improving ejection efficiency.

[0038] When the liquid is highly viscous, the flow path resistance is large, which can lead to a shortage of liquid supply. The following solutions are available, but each has its own drawbacks. <Solution 1> The voltage applied to the driving element 301 is increased to increase the pressure change in the pressure chamber 330. Solution 1 has the disadvantage of increasing the risk of burning out the driving element 301 and shortening its lifespan. <Solution 2> The pressure chamber 330 is enlarged to increase the change in volume that accompanies a change in pressure. Solution 2 has the disadvantage of increasing the overall size of the liquid jet head. It also has the disadvantage of causing liquid to flow back from the pressure chamber 330 into the common liquid chamber 110, resulting in a shortage of liquid supply around the nozzle 200.

[0039] In contrast, the backflow suppression unit 500 can efficiently supply liquid to the nozzle 200 and eject liquid from the nozzle 200 without causing the disadvantages of solutions 1 and 2.

[0040] The difference in the cross-sectional area between the main channel 510 and the sub-channel 520 of the backflow prevention unit 500 is preferably small. The cross-sectional area of ​​the main channel 510 of the backflow prevention unit 500, in other words, the cross-sectional area of ​​the portion of the main channel 510 from the first position P1 to the second position P2, is preferably in the range of 1 / 2 to 2 times the cross-sectional area of ​​the sub-channel 520, more preferably in the range of 1 / 2 to 3 / 2 times the cross-sectional area of ​​the sub-channel 520, and particularly preferably in the range of 0.7 to 1.3 times the cross-sectional area of ​​the sub-channel 520. The cross-sectional area of ​​the sub-channel 520 is the value obtained by dividing the volume of the sub-channel 520 by the length of the sub-channel 520 in the range from the first position P1 to the second position P2. The length of the sub-channel 520 is the length of a curve passing through the center of the sub-channel 520. The cross-sectional area of ​​the main channel 510 is calculated in a similar manner. The backflow suppression effect can be enhanced by setting the relationship between the flow path cross-sectional areas of the main flow path 510 and the sub-flow path 520 of the backflow suppression unit 500 within the above-mentioned range. If the flow path cross-sectional area of ​​the main flow path 510 of the backflow suppression unit 500 is excessively large, the backflow suppression effect may not be sufficient. Furthermore, if the flow path cross-sectional area of ​​the sub-flow path 520 is excessively large, it may be difficult to supply liquid to the pressure chamber 330.

[0041] Furthermore, it is preferable that the flow path cross-sectional area of ​​the main flow path 510 and the flow path cross-sectional area of ​​the sub-flow path 520 are each smaller than the flow path cross-sectional area of ​​the pressure chamber 330. In this way, the flow path cross-sectional areas of the main flow path 510 and the sub-flow path 520 are small and the flow path resistance is large, so that the effect of suppressing backflow can be further improved.

[0042] It is also preferable that the difference in flow path resistance between the main flow path 510 and the sub-flow path 520 of the backflow prevention unit 500 is small. For example, the flow path resistance of the sub-flow path 520 is preferably 1 / 2 to 2 times the flow path resistance of the main flow path 510 of the backflow prevention unit 500, and is preferably 1 / 2 to 3 / 2 times the flow path resistance of the main flow path 510 of the backflow prevention unit 500.

[0043] It is also preferable that the difference between the flow path cross-sectional area of ​​the first portion 521 of the sub-flow path 520 and the flow path cross-sectional area of ​​the second portion 522 is small. For example, the flow path cross-sectional area of ​​the first portion 521 is preferably 1 / 2 to 2 times the flow path cross-sectional area of ​​the second portion 522, and is preferably in the range of 1 / 2 to 3 / 2 times the flow path cross-sectional area of ​​the second portion 522.

[0044] To enhance the backflow suppression effect, it is preferable that the backflow suppression unit 500 is located as close to the pressure chamber 330 as possible. Specifically, for example, it is preferable that the distance of the main flow channel 510 from the first position P1 to the pressure chamber 330 is shorter than the distance of the main flow channel 510 from the first position P1 to the common liquid chamber 110. The distance of the main flow channel 510 here refers to the flow channel length of the main flow channel 510.

[0045] 8 is a diagram showing another example of a flow path including a backflow prevention unit 501. The backflow prevention unit 501 has two sub-flow paths 520 and 530 that are provided in series along one main flow path 510.

[0046] FIG. 9 is an enlarged view of the backflow suppression unit 501 shown in FIG. 8. The first sub-channel 520 has the configuration described in FIG. 6. The second sub-channel 530 has the same configuration as the first sub-channel 520. That is, the second sub-channel 530 is configured to connect a third position P3 of the main channel 510 to a fourth position P4 of the main channel 510 that is farther from the pressure chamber 330 than the third position P3. The second sub-channel 530 includes a third portion 533 extending from the third position P3 in the third direction D3, a fourth portion 534 extending from the third position P3 in the third direction D3, and a curved portion 535 between the two portions 533 and 534. An island-shaped portion 536 is formed in the center of the second sub-channel 530, and the fluid flowing through the second sub-channel 530 flows in a detour around the island-shaped portion 536.

[0047] At the third position P3, the angle α formed between the third direction D3 and a third supply direction Ds3, which is the direction in which the liquid flows through the main channel 510 toward the pressure chamber 330, is an obtuse angle. Also, at the fourth position P4, the angle β formed between the fourth direction D4 and a fourth supply direction Ds4, which is the direction in which the liquid flows through the main channel 510 toward the pressure chamber 330, is an obtuse angle. In the example of Fig. 9, since the main channel 510 has a linear shape, the third supply direction Ds3 and the fourth supply direction Ds4 are the same.

[0048] When the first sub-channel 520 is arranged on one side of the main channel 510 in the Y direction (the direction in which the pressure chambers 330 are arranged), it is preferable that the second sub-channel 530 is also arranged on the same side of the main channel 510 in the Y direction. In this way, the two sub-channels 520, 530 are arranged on the same side of the main channel 510, which prevents the size of the pressure chambers 330 from increasing in size in the direction in which the pressure chambers 330 are arranged.

[0049] 8 and 9, a plurality of sub-flow paths may be provided in the first portion 320P1 of the supply flow path 320, i.e., in the pressure chamber substrate 250. As the number of sub-flow paths increases, the flow path resistance of the liquid flowing back through the backflow suppression portion 501 increases, thereby making it possible to further reduce backflow.

[0050] The multiple sub-flow paths may be arranged in parallel instead of in series as in the example of Fig. 8. For example, two sub-flow paths may be arranged at opposing positions on either side of one main flow path 510. The various configurations and features described with reference to Figs. 5 to 9 can also be applied to other embodiments described later.

[0051] In the first embodiment described above, the backflow suppression unit 500 having the main flow path 510 and the sub-flow path 520 is provided in the supply flow path 320, so that the supply of liquid to the nozzle 200 and the ejection of liquid from the nozzle 200 can both be performed efficiently. Furthermore, since the ejection efficiency is improved, the drive voltage of the drive element can be reduced. Another advantage is that there is no need to increase the size of the liquid ejection head.

[0052] B. Second embodiment: Fig. 10 is a cross-sectional view of the liquid jet head 102 according to the second embodiment, and Fig. 11 is an enlarged view of the backflow suppression unit 600 according to the second embodiment. The main difference between the second embodiment and the first embodiment described above is only the position where the backflow suppression unit 600 is installed, and the other configurations are substantially the same as those of the first embodiment.

[0053] In the second embodiment, the backflow suppression section 600 is provided in a second portion 320P2 of the supply flow path 320 that extends in the Z direction. The backflow suppression section 600 has substantially the same effects as the backflow suppression section 500 of the first embodiment. Furthermore, the preferred configurations and features of the backflow suppression section 500 described with reference to FIGS. 5 to 7 can also be applied to the backflow suppression section 600.

[0054] The backflow suppression unit 600 has a main channel 610 extending along the Z direction and a sub-channel 620. The sub-channel 620 includes a first portion 621, a second portion 622, and a curved portion 623, and is configured as a loop-shaped channel that detours around an island-shaped portion 624. The main channel 610 has a configuration corresponding to the main channel 510 of the backflow suppression unit 500, and the sub-channel 620 has a configuration corresponding to the sub-channel 520 of the backflow suppression unit 500, so detailed description thereof will be omitted. The backflow suppression unit 600 is formed in a communicating plate 140 that is stacked in a stacking direction perpendicular to the surface of the pressure chamber substrate 250. The main channel 610 has a portion that is formed in the communicating plate 140 and extends in the stacking direction, and a portion that is formed in the pressure chamber substrate 250 and extends in the X direction.

[0055] However, in the second embodiment, the main flow path 610 does not have to be formed in the pressure chamber substrate 250. In other words, the main flow path 610 may be formed only in the communication plate 140. That is, at least a part of the main flow path 610 is formed in the communication plate 140. When the main flow path 610 is formed only in the communication plate 140, the width of the pressure chamber 330 in the X direction can be increased by the amount corresponding to the absence of the main flow path 610 in the pressure chamber substrate 250.

[0056] The backflow suppression section 600 is formed on the communication plate 140, which is made up of a plurality of laminated plate-like members. On the other hand, the backflow suppression sections 500, 501 of the first embodiment are formed on the pressure chamber substrate 250, and can be formed by etching a single silicon substrate. Therefore, the backflow suppression sections 500, 501 of the first embodiment are easier to form than the backflow suppression section 600 of the second embodiment.

[0057] 12 is a diagram showing another example of a flow path including a backflow prevention unit 601 in the second embodiment. In this backflow prevention unit 601, two sub-flow paths 620 are arranged at opposing positions on either side of a single main flow path 610. As can be seen from this example, the backflow prevention unit 600 can be configured to include multiple sub-flow paths 620.

[0058] The second embodiment also achieves substantially the same effects as the first embodiment. In the first embodiment, a backflow suppression section 500 having a planar configuration can be provided, whereas in the second embodiment, a backflow suppression section 600 having a three-dimensional configuration can be provided.

[0059] C. Third embodiment: Fig. 13 is a cross-sectional view of the liquid jet head 103 according to the third embodiment, and Fig. 14 is a diagram showing a part of the flow path as viewed from the bottom of the liquid jet head 103. The main differences between this liquid jet head 103 and the liquid jet head 101 according to the first embodiment are as follows. (1) The plurality of nozzles 200 constitutes only one nozzle row NL. (2) An upstream pressure chamber 331 and a downstream pressure chamber 332 are provided for one nozzle 200. (3) A first common liquid chamber 111 for storing liquid supplied from the outside and a second common liquid chamber 112 for storing liquid recovered to the outside are provided. (4) A nozzle-specific flow path 130 is formed to connect the first common liquid chamber 111, the nozzle 200, and the second common liquid chamber 112. (5) The circulation mechanism 60 for circulating the liquid is provided outside the liquid jet head 103 .

[0060] The nozzle-specific flow path 130 has an upstream pressure chamber 331 and a downstream pressure chamber 332. Drive elements 301 and 302 that drive the pressure chambers 331 and 332 are installed in the pressure chambers 331 and 332, respectively. When ejecting liquid from the nozzle 200, it is preferable that the multiple drive elements 301 and 302 corresponding to one nozzle 200 are driven simultaneously and in phase. The downstream pressure chamber 332 does not have to be provided. In other words, the drive element 302 does not have to be provided in the nozzle-specific flow path 130 between the nozzle 200 and the second common liquid chamber 112.

[0061] A circulation mechanism 60 is connected to the common liquid chambers 111, 112. The circulation mechanism 60 supplies liquid to the first common liquid chamber 111 and recovers liquid discharged from the second common liquid chamber 112 for re-supply to the first common liquid chamber 111. The circulation mechanism 60 has a first supply pump 61, a second supply pump 62, a storage container 63, a circulation recovery flow path 64, and a circulation supply flow path 65.

[0062] The first supply pump 61 is a pump that supplies the liquid stored in the liquid storage section 420 to the storage container 63. The storage container 63 is a sub-tank that temporarily stores the liquid supplied from the liquid storage section 420. The circulation recovery channel 64 is interposed between the second common liquid chamber 112 and the storage container 63, and is a channel for recovering the liquid from the second common liquid chamber 112 to the storage container 63. The liquid stored in the liquid storage section 420 is supplied to the storage container 63 from the first supply pump 61. Furthermore, the liquid that was supplied from the first common liquid chamber 111 to the individual nozzle channels 130 but was not ejected from the nozzles 200 and was recovered from the individual nozzle channels 130 to the second common liquid chamber 112 is supplied to the storage container 63 via the circulation recovery channel 64. The second supply pump 62 is a pump that sends out the liquid stored in the storage container 63. The circulation supply flow path 65 connects the first common liquid chamber 111 and the storage container 63 , and is a flow path for supplying the liquid in the storage container 63 to the first common liquid chamber 111 .

[0063] An opening 161 at the upper end of the first common liquid chamber 111 is connected to a circulation supply flow path 65 located outside the liquid jet head 103. An opening 162 at the upper end of the second common liquid chamber 112 is connected to a circulation recovery flow path 64 located outside the liquid jet head 103.

[0064] The nozzle-specific flow path 130 has a supply flow path 321 that connects the first common liquid chamber 111 and the upstream pressure chamber 331, a first communication path 341 that connects the upstream pressure chamber 331 and the nozzle 200, a second communication path 342 that connects the nozzle 200 and the downstream pressure chamber 332, and a recovery flow path 322 that connects the downstream pressure chamber 332 and the second common liquid chamber 112. Point P111 shown in Figure 13 is the end point of the first common liquid chamber 111, and point P112 is the start point of the second common liquid chamber 112. The flow path that connects these points P111 and P112 is the nozzle-specific flow path 130.

[0065] The upstream pressure chamber 331 extends in the X direction and is provided between the nozzle 200 and the first common liquid chamber 111. The downstream pressure chamber 332 extends in the X direction and is provided between the nozzle 200 and the second common liquid chamber 112.

[0066] The supply flow path 321 includes a first portion 321P1 extending in the X direction adjacent to the upstream pressure chamber 331, and a second portion 321P2 extending in the Z direction from an end of the first portion 321P1 to reach the first common liquid chamber 111.

[0067] Fig. 15 is a diagram showing a portion of the nozzle-specific flow path 130. A backflow suppression section 500 is provided in the first portion 321P1 of the supply flow path 321. This backflow suppression section 500 is the same as the backflow suppression section 500 of the first embodiment described with reference to Figs. 5 to 7. Note that the backflow suppression section 501 described with reference to Figs. 8 and 9 may also be used.

[0068] Although the supply flow path 321 is provided with a backflow suppression unit 500, it is preferable that the recovery flow path 322, which is located downstream of the nozzle 200, is not provided with a backflow suppression unit 500. The reason for this is that if a backflow suppression unit 500 is provided downstream of the nozzle 200, the circulation of the liquid by the circulation mechanism 60 may be hindered.

[0069] 16 is a diagram showing yet another example of a flow path provided with a backflow suppression unit. In this example, two upstream pressure chambers 331 are provided for one nozzle 200. Each upstream pressure chamber 331 is connected to the first common liquid chamber 111 and the nozzle 200 by a pressure chamber-specific flow path 131 that includes a backflow suppression unit 500. As can be seen from this example, when N is an integer greater than or equal to 1, it is possible to configure a liquid jet head so that liquid is jetted from one nozzle 200 using N upstream pressure chambers 331 and N downstream pressure chambers 332. In this case, N pressure chamber-specific flow paths 131 are formed.

[0070] The above-described third embodiment also achieves substantially the same effects as the first embodiment. Furthermore, in the third embodiment, multiple pressure chambers are provided for one nozzle 200, so that liquid with an even higher viscosity can be ejected more efficiently than in the first embodiment.

[0071] D. Fourth embodiment: Figure 17 is a cross-sectional view of the liquid jet head 104 in the fourth embodiment. The main difference between the fourth embodiment and the third embodiment described above is the position where the backflow suppression unit 600 is installed; the other configurations are almost the same as those in the third embodiment.

[0072] In the fourth embodiment, the backflow suppression section 600 is provided in a second portion 321P2 extending in the Z direction of the supply flow path 321 of the nozzle-specific flow path 130. It is preferable that the backflow suppression section 600 is not provided in the recovery flow path 322. The backflow suppression section 600 is the same as the backflow suppression section 600 of the second embodiment described in FIG. 11. Note that, as in FIG. 12, multiple sub-flow paths may be provided around one main flow path 610. The fourth embodiment also achieves substantially the same effects as the second embodiment.

[0073] E. Other forms: The liquid ejection apparatus exemplified in the above-described embodiment can be employed in various devices such as facsimile machines and copiers, as well as devices dedicated to printing. However, the uses of the liquid ejection apparatus are not limited to printing. For example, a liquid ejection apparatus that ejects a solution of a coloring material is used as a manufacturing apparatus for forming color filters for display devices such as liquid crystal display panels. Furthermore, a liquid ejection apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes on a wiring board. Furthermore, a liquid ejection apparatus that ejects a solution of an organic substance related to a living body is used as a manufacturing apparatus for manufacturing biochips, for example.

[0074] The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following aspects. The technical features in the above embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0075] (1) A liquid jet head according to one aspect of the present disclosure includes a plurality of nozzles for ejecting liquid, pressure chambers communicating with the nozzles and applying pressure to the liquid, a common liquid chamber communicating with the plurality of nozzles, and a supply flow path connecting the common liquid chamber to the pressure chambers and supplying the liquid to the pressure chambers. The supply flow path includes a main flow path and a first sub-flow path connecting a first position of the main flow path to a second position of the main flow path that is farther from the pressure chambers than the first position. The first sub-flow path has a first portion extending from the first position in a first direction and a second portion extending from the second position in a second direction. At the first position, the angle formed between the direction of flow of the liquid through the main flow path toward the pressure chambers and the first direction is an obtuse angle, and at the second position, the angle formed between the direction of flow of the liquid through the main flow path toward the pressure chambers and the second direction is an obtuse angle. With this liquid jet head, the flow path resistance is greater for reverse flow than for forward flow of liquid toward the pressure chamber. Therefore, the effect of suppressing reverse flow can be achieved without narrowing the flow path diameter too much. Therefore, it is possible to reduce the reverse flow of liquid from the pressure chamber without interfering with the supply of liquid. Furthermore, by reducing reverse flow, it is possible to increase the amount of liquid flowing from the pressure chamber to the nozzle during ejection, thereby improving ejection efficiency.

[0076] (2) In the liquid jet head described above, an angle formed between a direction opposite to a direction in which the liquid flows through the main flow channel toward the pressure chamber at the first position and the first direction may be 45 degrees or less. According to this liquid jet head, the backflowing liquid can easily enter the first sub-channel from the first position, so that the effect of reducing backflow can be further obtained.

[0077] (3) In the liquid jet head described above, the pressure chamber and the first sub-channel may be formed in a pressure chamber substrate made of silicon. According to this liquid jet head, the pressure chamber and the first sub-channel can be formed by etching the pressure chamber substrate made of silicon.

[0078] (4) In the above liquid jet head, the pressure chamber may be formed in a pressure chamber substrate made of silicon, the first sub-channel and at least a portion of the main channel may be formed in a communicating plate stacked in a stacking direction perpendicular to a surface of the pressure chamber substrate, and the at least a portion of the main channel may extend in the stacking direction. According to this liquid jet head, the first sub-flow path can be formed by stacking the communication plates. Furthermore, even if the first sub-flow path is provided, the size of the pressure chamber in the extension direction can be maintained long.

[0079] (5) In the above liquid jet head, the main flow path may have a third position and a fourth position, and the supply flow path may have a second sub-flow path that is different from the first sub-flow path and connects the third position to the fourth position that is farther from the pressure chamber than the third position. The second sub-flow path may have a third portion extending from the third position in a third direction and a fourth portion extending from the fourth position in a fourth direction. At the third position, the angle formed between the direction in which the liquid flows through the main flow path toward the pressure chamber and the third direction may be an obtuse angle, and at the fourth position, the angle formed between the direction in which the liquid flows through the main flow path toward the pressure chamber and the fourth direction may be an obtuse angle. According to this liquid jet head, the flow path resistance increases, so that backflow can be further reduced.

[0080] (6) In the liquid jet head described above, the main flow path may have a portion extending from the first position to the second position, and the cross-sectional area of ​​the portion of the main flow path may be in the range of 1 / 2 to 2 times the cross-sectional area of ​​the first sub-flow path. According to this liquid jet head, it is possible to enhance the effect of suppressing backflow.

[0081] (7) In the liquid jet head, the distance from the first position to the pressure chamber may be shorter than the distance from the first position to the common liquid chamber. According to this liquid jet head, it is possible to enhance the effect of suppressing backflow.

[0082] (8) A liquid jet head according to a second aspect of the present disclosure includes a plurality of nozzles for ejecting liquid, pressure chambers communicating with the nozzles and applying pressure to the liquid, a common liquid chamber communicating with the plurality of nozzles, and a supply flow path connecting the common liquid chamber and the pressure chamber and supplying the liquid to the pressure chamber. The supply flow path has a main flow path and a sub-flow path connecting a first position of the main flow path to a second position of the main flow path different from the first position. When a flow direction from the main flow path toward the pressure chamber is defined as a forward direction and a flow direction from the pressure chamber toward the main flow path is defined as a reverse direction, when a flow of the liquid in the reverse direction occurs in the main flow path, the sub-flow path converts the flow of the liquid that branches off from the main flow path to the sub-flow path at the first position so that the liquid flows in the main flow path in the forward direction and merges with the main flow path at the second position. With this liquid jet head, the flow path resistance is greater for reverse flow than for forward flow of liquid toward the pressure chamber. Therefore, the effect of suppressing reverse flow can be achieved without narrowing the flow path diameter too much. Therefore, it is possible to reduce the reverse flow of liquid from the pressure chamber without interfering with the supply of liquid. Furthermore, by reducing reverse flow, it is possible to increase the amount of liquid flowing from the pressure chamber to the nozzle during ejection, thereby improving ejection efficiency.

[0083] The present disclosure may be realized in various forms other than a liquid ejection head, such as a liquid ejection device, a control method for a liquid ejection device, a computer program for realizing the control method, or a non-transitory recording medium on which the computer program is recorded. [Explanation of symbols]

[0084] 59...wiring board, 60...circulation mechanism, 61...first supply pump, 62...second supply pump, 63...storage container, 64...recovery flow path for circulation, 65...supply flow path for circulation, 70...drive circuit, 101-104...liquid jet head, 110...common liquid chamber, 111...first common liquid chamber, 112...second common liquid chamber, 120...flow path for nozzle, 130...flow path for nozzle, 131...flow path for pressure chamber, 140...communicating plate, 150... Sealing film, 160...casing portion, 161...opening, 162...opening, 200...nozzle, 240...nozzle plate, 250...pressure chamber substrate, 300...pressure chamber, 301...driving element, 302...driving element, 310...vibration plate, 320...supply flow path, 320P1...first portion, 320P2...second portion, 321...supply flow path, 321P1...first portion, 321P2...second portion, 322...recovery flow path, 330...pressure pressure chamber, 331...upstream pressure chamber, 332...downstream pressure chamber, 340...communication passage, 341...first communication passage, 342...second communication passage, 400...liquid injection device, 420...liquid storage section, 430...movement mechanism, 432...belt, 434...carriage, 440...conveyance mechanism, 450...control section, 460...input reception section, 461...input section, 462...output section, 500...backflow prevention section, 501...backflow prevention section, 510... Main channel, 520... Sub-channel (first sub-channel), 521... First part, 522... Second part, 523... Curved part, 524... Island-like part, 530... Second sub-channel, 533... Third part, 534... Fourth part, 53 5...Curved part, 536...Island-like part, 600...Backflow suppressing part, 601...Backflow suppressing part, 610...Main channel, 620...Sub-channel, 621...First part, 622...Second part, 623...Curved part, 624...Island-like part

Claims

1. A liquid jet head, A plurality of nozzles for ejecting liquid; a pressure chamber communicating with the nozzle and applying pressure to the liquid; a common liquid chamber communicating with the plurality of nozzles; a supply flow channel that connects the common liquid chamber and the pressure chamber and supplies the liquid to the pressure chamber; Equipped with the supply flow path includes a main flow path and a first sub-flow path that connects a first position of the main flow path to a second position of the main flow path that is farther from the pressure chamber than the first position, the first sub-channel has a first portion extending in a first direction from the first position and a second portion extending in a second direction from the second position; an angle formed between a direction in which the liquid flows through the main flow channel toward the pressure chamber at the first position and the first direction is an obtuse angle; a liquid ejection head, wherein an angle formed between a direction in which the liquid flows through the main flow channel toward the pressure chamber at the second position and the second direction is an obtuse angle;

2. The liquid jet head according to claim 1 , a liquid ejection head, wherein an angle formed between a direction opposite to a direction in which the liquid flows through the main flow channel toward the pressure chamber at the first position and the first direction is 45 degrees or less;

3. The liquid jet head according to claim 1 , The liquid ejecting head, wherein the pressure chamber and the first sub-channel are formed in a pressure chamber substrate made of silicon.

4. The liquid jet head according to claim 1 , The pressure chamber is formed in a pressure chamber substrate made of silicon, the first sub-channel and at least a portion of the main channel are formed in a communication plate that is stacked in a stacking direction perpendicular to a surface of the pressure chamber substrate, The liquid jet head, wherein the at least part of the main flow path extends in the stacking direction.

5. The liquid jet head according to claim 1 , the main flow path has a third position and a fourth position; the supply flow path has a second sub-flow path that is different from the first sub-flow path and connects the third position to the fourth position that is farther from the pressure chamber than the third position, the second sub-channel has a third portion extending in a third direction from the third position and a fourth portion extending in a fourth direction from the fourth position, an angle formed between a direction in which the liquid flows through the main flow channel toward the pressure chamber at the third position and the third direction is an obtuse angle; a liquid ejection head, wherein an angle formed between a direction in which the liquid flows through the main flow channel toward the pressure chamber at the fourth position and the fourth direction is an obtuse angle;

6. The liquid jet head according to claim 1 , the main flow path has a portion from the first position to the second position; a cross-sectional area of ​​the portion of the main flow path is in the range of 1 / 2 to 2 times the cross-sectional area of ​​the first sub-flow path.

7. The liquid jet head according to claim 1 , a liquid ejection head, wherein a distance from the first position to the pressure chamber is shorter than a distance from the first position to the common liquid chamber;

8. A liquid jet head, A plurality of nozzles for ejecting liquid; a pressure chamber communicating with the nozzle and applying pressure to the liquid; a common liquid chamber communicating with the plurality of nozzles; a supply flow channel that connects the common liquid chamber and the pressure chamber and supplies the liquid to the pressure chamber; Equipped with the supply flow path has a main flow path and a sub-flow path connecting a first position of the main flow path and a second position of the main flow path different from the first position, When the direction of flow from the main flow path to the pressure chamber is defined as a forward direction and the direction of flow from the pressure chamber to the main flow path is defined as a reverse direction, When a flow of the liquid in the reverse direction occurs in the main flow path, the secondary flow path converts the flow of the liquid so that the liquid branching off from the main flow path to the secondary flow path at the first position flows in the forward direction through the main flow path and merges with the main flow path at the second position.

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