Liquid discharge head

Abstract

To maintain a buffer function performed by a gas storage part communicated with a common passage.SOLUTION: A head 1 includes a passage member 21 having a plurality of individual passages 13 including nozzles 15 respectively and a common passage 12 communicating with the plurality of individual passages and extending in a first direction D1. The passage member 21 has a gas storage part 55 that can store gas, in a state where liquid is stored in the plurality of individual passages 13 and the common passage 12. The gas storage part 55 is communicated with a side surface 12S in a second direction D2 of the common passage 12.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head provided with a flow path member having a plurality of individual flow paths and a common flow path. [Background technology]

[0002] Patent Document 1 describes a liquid ejection head equipped with a recording element (channel member) having a plurality of channels (individual channels) each including an ejection port, and a supply channel (common channel) communicating with the plurality of channels. The recording element of this liquid ejection head has a plurality of recesses and a plurality of spaces (gas containing sections) formed by covering a portion of each recess with a cover section. Each space is located below the supply channel and contains air bubbles. The air bubbles contained in the spaces function as a buffer, damping meniscus vibration at the ejection port. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-178609 Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid ejection head described in Patent Document 1, each space is connected to the underside of the supply channel. Therefore, when bubbles in the space grow with an increase in temperature, they may move into the supply channel due to buoyancy. In this case, the amount of gas in the space decreases, reducing the buffer function.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a liquid ejection head that is capable of maintaining the buffer function of a gas storage section that communicates with a common flow path. [Means for solving the problem]

[0006] The liquid ejection head of the present invention comprises a flow path member having a plurality of individual flow paths, each including a nozzle, arranged in a first direction perpendicular to the vertical direction, and a common flow path that communicates with the plurality of individual flow paths and extends in the first direction, the flow path member having a gas storage section that can store gas when liquid is stored in the plurality of individual flow paths and the common flow path, and the gas storage section is connected to a side surface of the common flow path in a second direction perpendicular to the vertical direction. [Effects of the Invention]

[0007] According to the liquid ejection head of the present invention, the gas storage section is connected to the side of the common flow path, so that the gas stored in the gas storage section is less likely to move into the common flow path due to buoyancy, thereby maintaining the buffer function of the gas stored in the gas storage section. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view of a printer including a head according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the printer. [Figure 3] FIG. [Figure 4] FIG. 4 is a cross-sectional view of the head taken along line IV-IV in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Embodiment> First, with reference to Figure 1, the overall configuration of a printer 100 equipped with a head 1 according to one embodiment of the present invention will be described. In the following description, the first direction D1 and the second direction D2 are horizontal directions that are perpendicular to the up-down direction D3. In this embodiment, the up-down direction D3 is along the vertical direction, but it may also be a vertical direction that intersects with the vertical and horizontal directions. The first direction D1 is perpendicular to the second direction D2.

[0010] <Overall printer configuration> The printer 100 includes a housing 100A, a head unit 1X, a platen 3, a transport mechanism 4, and a control unit 5. The head unit 1X, the platen 3, the transport mechanism 4, and the control unit 5 are arranged inside the housing 100A. The printer 100 also includes a button (not shown) arranged on the outer surface of the housing 100A.

[0011] The length of the head unit 1X in a first direction D1 is longer than the length of the head unit 1X in the transport direction along a second direction D2. The first direction D1 is a direction along the width of the paper 9. The head unit 1X is fixed to a housing 100A. The head unit 1X is a line type.

[0012] The head unit 1X includes four heads 1. The four heads 1 are arranged in a staggered pattern in the first direction D1. The length of the heads 1 in the first direction D1 is longer than the length of the heads 1 in the second direction D2.

[0013] The platen 3 is a plate along a plane perpendicular to the up-down direction D3, and is disposed below the head unit 1 X. A paper sheet 9 is supported on the upper surface of the platen 3.

[0014] The transport mechanism 4 has two roller pairs 4A and 4B arranged in the second direction D2 with the platen 3 sandwiched between them. When the transport motor 4C (see FIG. 2) is driven under the control of the control unit 5, the roller pairs 4A and 4B rotate while sandwiching the paper 9, and the paper 9 is transported in the transport direction along the second direction D2.

[0015] 2, the control unit 5 includes a CPU 5A, a ROM 5B, and a RAM 5C. The CPU 5A executes various controls in accordance with the programs and data stored in the ROM 5B and RAM 5C, based on data input from an external device or the buttons. The external device is, for example, a personal computer (PC).

[0016] The ROM 5B stores programs and data for the CPU 5A to perform various controls. The RAM 5C temporarily stores data used when the CPU 5A executes the programs.

[0017] <head> 3, the head 1 has a flow path member 21 and an actuator member 22. Both the flow path member 21 and the actuator member 22 have a rectangular shape in which the length in the first direction D1 is longer than the length in the second direction D2 in a plane perpendicular to the up-down direction D3.

[0018] 3, a supply port 111 and a return port 112 are opened on the upper surface 21A of the flow path member 21. The supply port 111 is disposed at one end of the flow path member 21 in the first direction D1. The return port 112 is disposed at the other end of the flow path member 21 in the first direction D1. The supply port 111 and the return port 112 communicate with ink tanks via tubes. The flow path member 21 has a common flow path 12, a plurality of individual flow paths 13, a damper chamber 19, and a plurality of gas containing sections 55.

[0019] The common flow path 12 extends in a first direction D1. A supply port 111 is connected to one end of the common flow path 12 in the first direction D1. A return port 112 is connected to the other end of the common flow path 12 in the first direction D1. The common flow path 12 communicates with an ink tank via the supply port 111 and the return port 112, and also communicates with a plurality of individual flow paths 13.

[0020] 3 and 4, the gas storage units 55 communicate with both side surfaces 12S of the common flow path 12 in the second direction D2. The gas storage units 55 form four gas storage unit rows 50R arranged at equal intervals along the first direction D1. The four gas storage unit rows 50R are arranged in pairs in the second direction D2 and in the vertical direction D3.

[0021] The damper chamber 19 is disposed below the common flow path 12. The damper chamber 19 also extends in the first direction D1.

[0022] 4, the individual flow paths 13 include nozzles 15, pressure chambers 16, communication flow paths 17, and connection flow paths 18. One end of the communication flow path 17 communicates with the nozzle 15, and the other end communicates with the pressure chamber 16. One end of the connection flow path 18 communicates with the common flow path 12, and the other end communicates with the pressure chamber 16. The communication flow path 17 communicates with one end of the pressure chamber 16, and the connection flow path 18 communicates with the other end of the pressure chamber 16.

[0023] The flow path member 21 includes eleven plates 121 to 131. The flow path member 21 may be composed of twelve or more or ten or fewer plates. Of the eleven plates 121 to 131, the uppermost plate 121 has a plurality of pressure chambers 16 formed therein, and the lowermost plate 131 has a plurality of nozzles 15 formed therein.

[0024] A plurality of pressure chambers 16 open to the upper surface (upper surface 21A) of the plate 121, and a plurality of nozzles 15 open to the lower surface of the plate 131. The openings of the nozzles 15 are circular, and the openings of the pressure chambers 16 are generally rectangular and elongated in the second direction D2. In other words, the length (width) of the pressure chambers 16 in the first direction D1 is shorter than the length in the second direction D2.

[0025] The nozzles 15 are tapered downward. As shown in Figure 3, the nozzles 15 are arranged in a staggered pattern in the first direction D1 to form two nozzle rows 15R. Each nozzle row 15R is made up of a plurality of nozzles 15 aligned in the first direction D1.

[0026] 4, the common flow channel 12 is formed by interconnecting holes formed in five plates 124 to 128. Each common flow channel 12 overlaps in the up-down direction D3 with all of the pressure chambers 16 that communicate with the common flow channel 12.

[0027] Each gas storage unit 55 is connected to the common flow path 12 via a passage 51. When a liquid (e.g., ink) is introduced into the common flow path 12 and the individual flow paths 13, gas (e.g., air) that existed before the introduction remains in the gas storage unit 55. In other words, the gas storage unit 55 stores gas inside when ink is supplied to and stored in the common flow path 12 and the individual flow paths 13. When ink is stored in the common flow path 12, as shown in the enlarged view of region A in FIG. 4, the ink enters the passage 51, but almost no ink enters the gas storage unit 55, and the entire volume of the gas storage unit 55 is filled with gas. In the enlarged view in FIG. 4, ink is shown hatched, and the gas stored in the gas storage unit 55 is shown as an outline.

[0028] The gas contained in the gas containing section 55 absorbs pressure fluctuations of the ink in the common flow path 12. In other words, even if the pressure generated in the pressure chamber 16 when ink is ejected from the nozzle 15 is transmitted to the common flow path 12, the gas contained in the gas containing section 55 functions as a buffer that attenuates the pressure fluctuations of the ink in the common flow path 12. As a result, it is possible to prevent the pressure from being transmitted to other pressure chambers 16 (so-called crosstalk). The gas contained in the gas containing section 55 also functions as a buffer that attenuates vibrations transmitted due to meniscus vibrations in the nozzle 15 when ink is ejected.

[0029] Each gas storage section 55 communicates with the common flow path 12 via only one passage 51. Each passage 51 extends from the side surface 12S of the common flow path 12 in the second direction D2 and communicates with the gas storage section 55. The multiple passages 51 also form a passage row similar to the gas storage section row 50R. As shown in FIG. 3, the length W1 of the gas storage section 55 in the first direction D1 is longer than the length W2 of the passage 51. In this embodiment, the length W1 is in the range of 200 to 300 μm, and the length W2 is in the range of 50 to 100 μm.

[0030] 4, an upper surface 55A of the gas storage section 55 is located higher than an upper surface 51A of the passage 51 connected to the gas storage section 55. Furthermore, the length H1 of the gas storage section 55 in the vertical direction D3 is longer than the length H2 of the passage 51. In this embodiment, the length H1 is in the range of 200 to 300 μm, and the length H2 is in the range of 100 to 150 μm. In this embodiment, the thickness of each of the plates 124, 125, 127, and 128 is in the range of 100 to 150 μm.

[0031] Of the two gas storage section rows 50R aligned in the vertical direction D3, the gas storage section 55 included in the upper gas storage section row 50R is formed by holes formed in two plates 124, 125 connecting to each other and having the upper and lower openings of the connected holes blocked by two plates 123, 126. Of the two gas storage section rows 50R aligned in the vertical direction D3, the gas storage section 55 included in the lower gas storage section row 50R is formed by holes formed in two plates 127, 128 connecting to each other and having the upper and lower openings of the connected holes blocked by two plates 126, 129.

[0032] Of the two passage rows aligned in the vertical direction D3, the passages 51 included in the upper passage row are formed by holes formed in the plate 125, and connect the upper gas storage unit 55 and the common flow path 12. The holes forming the upper passages 51 have their upper and lower openings blocked by two plates 124 and 126. Of the two passage rows aligned in the vertical direction D3, the passages 51 included in the lower passage row are formed by holes formed in the plate 128, and connect the lower gas storage unit 55 and the common flow path 12. The holes forming the lower passages 51 have their upper and lower openings blocked by two plates 127 and 129. The holes formed in the plates 125 and 128 that form part of the gas storage unit 55, the passages 51, and part of the common flow path 12 are connected to each other in the second direction D2.

[0033] The damper chamber 19 is formed by blocking a hole formed in a plate 130 with two plates 129 and 131. The portion of the plate 129 sandwiched between the damper chamber 19 and the common flow path 12 functions as a damper 129A that mainly absorbs pressure fluctuations of the ink in the common flow path 12. In other words, even if the pressure generated in the pressure chamber 16 when ink is ejected from the nozzle 15 is transmitted to the common flow path 12, the damper 129A attenuates the pressure by elastically deforming, thereby preventing the above-mentioned crosstalk.

[0034] 3, the individual flow paths 13 are arranged in a first direction D1 to form two individual flow path rows 14R. These individual flow path rows 14R are aligned in a second direction D2. All of the individual flow paths 13 included in these individual flow path rows 14R communicate with the same common flow path 12.

[0035] 4, the communicating flow path 17 is connected to the upper end of the nozzle 15 and has a cylindrical shape. The communicating flow path 17 extends upward from the nozzle 15 and is connected to the pressure chamber 16. The communicating flow path 17 is formed by interconnecting holes formed in each of the nine plates 122 to 130, and has a diameter larger than that of the nozzle 15.

[0036] The connecting flow path 18 is formed by interconnecting holes formed in the two plates 122, 123, and is connected to the upper surface 12A of the common flow path 12. In other words, the inlets 13A from the common flow path 12 to the individual flow paths 13 are located on the upper surface 12A. The connecting flow path 18 extends upward from the upper end of the common flow path 12 toward the pressure chambers 16, and connects the common flow path 12 and the pressure chambers 16.

[0037] The ink in the ink tank is supplied to a common flow path 12 through a supply port 111 by driving a pump 10 shown in Figure 2 under the control of the control unit 5, and is distributed from the common flow path 12 to multiple individual flow paths 13.

[0038] Within the individual flow path 13, the volume of the pressure chamber 16 is reduced by driving the actuator unit 35 described later, and pressure is applied to the ink within the pressure chamber 16, causing it to pass through the communicating flow path 17 and be ejected as ink droplets from the nozzle 15.

[0039] The ink supplied from the supply port 111 moves in the common flow path 12 from one end to the other in the first direction D1, and reaches the return port 112. The ink that reaches the return port 112 is returned to the ink tank via a tube.

[0040] 4, the actuator member 22 is fixed to the upper surface 21A of the flow path member 21. The actuator member 22 includes a vibration plate 31 made of metal, a piezoelectric layer 32, and a plurality of individual electrodes 33.

[0041] The portions of the actuator member 22 that overlap with the pressure chambers 16 in the up-down direction D3 function as actuator portions 35. The actuator portions 35 are capable of independently deforming in response to the potentials applied to the individual electrodes 33.

[0042] The actuator section 35 is a thin-film piezoelectric element. A thin-film piezoelectric element is a so-called micro electro mechanical system (MEMS). The actuator section 35 is formed by sequentially depositing a thin film that will become the piezoelectric layer 32 and a thin film that will become the individual electrodes 33 on the upper surface of the diaphragm 31.

[0043] The vibration plate 31 is disposed on the upper surface 21A of the flow path member 21 so as to cover the multiple pressure chambers 16. The piezoelectric layer 32 is disposed on the upper surface of the vibration plate 31. The individual electrodes 33 are disposed on the upper surface of the piezoelectric layer 32 so as to overlap the pressure chambers 16 in the up-down direction D3.

[0044] The diaphragm 31 and the individual electrodes 33 are electrically connected to a driver IC 6. The driver IC 6 maintains the potential of the diaphragm 31 at ground potential, while changing the potential of the individual electrodes 33. The diaphragm 31 functions as a common electrode that is a common electrode for the multiple actuator elements 35.

[0045] The driver IC 6 generates a drive pulse signal based on a control signal from the control unit 5 and supplies the drive pulse signal to the individual electrode 33. The drive pulse signal changes the potential of the individual electrode 33 between a predetermined drive potential and ground potential. In this way, the actuator unit 35 is driven, and pressure is applied to the ink in the pressure chamber 16, causing ink droplets to be ejected from the nozzle 15 through the communicating flow path 17.

[0046] As described above, in the head 1 of this embodiment, the gas storage section 55 is in communication with the side surface 12S of the common flow path 12, so that the gas stored in the gas storage section 55 is less likely to move to the common flow path 12 due to buoyancy. Therefore, the buffer function of the gas stored in the gas storage section 55 can be maintained.

[0047] The length W2 of the passage 51 in the first direction D1 is shorter than the length W1 of the gas storage section 55 in the first direction D1. The length H2 of the passage 51 in the vertical direction D3 is shorter than the length H1 of the gas storage section 55 in the vertical direction D3. In this way, the passage 51 is narrower than the gas storage section 55. For this reason, the gas stored in the gas storage section 55 is less likely to move through the common flow path 12.

[0048] Furthermore, the lengths H1, W1 of the gas storage section 55 are greater than the lengths H2, W2 of the passage 51. This allows a larger amount of gas to be stored in the gas storage section 55. This improves the buffer function of the gas in the gas storage section 55.

[0049] In this embodiment, the gas storage unit 55 communicates with the common flow path 12 via one passage 51, thereby maintaining the buffer function of the gas in the gas storage unit 55. If the gas storage unit 55 communicates with the common flow path 12 via multiple passages 51, pressure fluctuations transmitted from the ink in the common flow path 12 to the gas in the gas storage unit 55 via one passage 51 would be transmitted to the ink in the common flow path 12 via the other passages 51, reducing the buffer function of the gas in the gas storage unit 55.

[0050] An upper surface 55A of the gas storage portion 55 is located higher than an upper surface 51A of the passage 51. This makes it even more difficult for the gas stored in the gas storage portion 55 to move toward the common flow path 12 due to buoyancy.

[0051] A plurality of gas storage sections 55 arranged in the vertical direction D3 communicate with the side surface 12S, which further improves the buffer function for the common flow path 12 and effectively attenuates pressure fluctuations of the ink in the common flow path 12.

[0052] A plurality of gas storage sections 55 arranged in the first direction D1 communicate with the side surface 12S, which further improves the buffer function for the common flow path 12 and effectively attenuates pressure fluctuations of the ink in the common flow path 12.

[0053] An inlet 13A to the individual flow paths 13 is disposed on the upper surface 12A of the common flow path 12. In a configuration in which the inlet 13A to the individual flow paths 13 is disposed on the upper surface 12A of the common flow path 12, there is a concern that gas may enter the individual flow paths 13. However, in this embodiment, the gas stored in the gas storage section 55 does not easily move to the common flow path 12, and therefore gas is unlikely to enter the individual flow paths 13.

[0054] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims.

[0055] In the above-described embodiment, the gas storage section 55 communicates with the side surface 12S of the common flow path 12 in the second direction D2, but the gas storage section 55 may also communicate with the side surface of the common flow path 12 in the first direction D1. In this case, the first direction D1 corresponds to the "second direction" of the present invention.

[0056] In addition, the side surface 12S of the common flow path 12 in this embodiment is a surface along the vertical direction, but it may be an arc-shaped side surface that is convex or concave toward the common flow path 12, or may be an inclined side surface that intersects with the vertical and horizontal directions. Furthermore, the side surface 12S is not limited to a flat surface, and may be an uneven or curved surface.

[0057] Furthermore, the gas storage section 55 may be open directly to the side surface 12S without passing through the passage 51. Furthermore, the cross-sectional shape of the gas storage section 55 in a plane perpendicular to the first direction D1 may be a triangle, a polygon with pentagons or more sides, a circle, an ellipse, or the like, and is not particularly limited.

[0058] Furthermore, the length H1 of the gas storage section 55 may be equal to or less than the length H2. Furthermore, the length W1 of the gas storage section may be equal to or less than the length W2.

[0059] Furthermore, the upper surface 55A of the gas storage section 55 may be disposed at a height position equal to or lower than the upper surface 51A of the passage 51.

[0060] Furthermore, the gas storage section 55 may be in communication with the side surface 12S of the common flow path 12 via two or more passages 51.

[0061] Furthermore, the plurality of gas storage sections 55 do not have to be aligned in at least one of the vertical direction and the first direction D1. Alternatively, the plurality of gas storage sections 55 may be aligned in a number of three or more in at least one of the vertical direction and the first direction D1.

[0062] The inlet 13A from the common flow channel 12 to the individual flow channels 13 may be disposed on a surface of the common flow channel 12 other than the upper surface 12A.

[0063] In the above-described embodiment, the electrodes constituting the actuator section 35 have a two-layer structure including an individual electrode and a common electrode, but may have a three-layer structure. For example, a three-layer structure is a structure including a drive electrode to which a high potential or a low potential is selectively applied, a high-potential electrode that is held at a high potential, and a low-potential electrode that is held at a low potential.

[0064] The type of liquid ejection head of the present invention is not limited to the line type, but may also be a serial type.

[0065] The object onto which the droplets are ejected is not limited to paper, but may be, for example, a cloth, a substrate, or plastic.

[0066] The droplets ejected from the nozzles are not limited to ink droplets, but may be droplets of a treatment liquid that aggregates or precipitates components in the ink, for example.

[0067] The present invention is not limited to printers, but can also be applied to facsimiles, copiers, and multifunction peripherals. The present invention can also be applied to liquid ejection heads used for purposes other than image recording. For example, the present invention can be applied to liquid ejection heads that eject conductive liquid onto a substrate to form a conductive pattern. [Explanation of symbols]

[0068] 1 head (liquid ejection head) 12 Common flow path 12A top 12S side 13 Individual flow path 13A Entrance 15 nozzles 21 Flow path member 51 Passage 51A Top 55 Gas storage section 55A Top D1 1st direction D2 2nd direction D3 Up and down direction H1,H2 length W1, W2 length

Claims

1. a plurality of individual flow paths each including a nozzle and arranged in a first direction perpendicular to the up-down direction; a flow path member having a common flow path communicating with the plurality of individual flow paths and extending in the first direction; The flow path member is a gas storage section capable of storing gas in a state in which liquid is stored in the plurality of individual flow paths and the common flow path; The liquid ejection head is characterized in that the gas storage section communicates with a side surface of the common flow path in a second direction perpendicular to the up-down direction.

2. the gas storage section communicates with the common flow path via a passage; the second direction is perpendicular to the first direction, 2. The liquid ejection head according to claim 1, wherein the length of the passage is shorter than the length of the gas containing portion in at least one of the vertical direction and the first direction.

3. 3. The liquid ejection head according to claim 2, wherein the gas storage section communicates with the common flow path via only one of the passages.

4. 3. The liquid ejection head according to claim 2, wherein an upper surface of the gas storage portion is located above an upper surface of the passage.

5. a length of the gas storage portion in the first direction is greater than a length of the passage in the first direction; 3. The liquid ejection head according to claim 2, wherein the vertical length of the gas storage portion is greater than the vertical length of the passage.

6. 2. The liquid ejection head according to claim 1, wherein a plurality of the gas storage sections arranged in a vertical direction communicate with the side surface of the common flow path.

7. the second direction is perpendicular to the first direction, The liquid ejection head according to claim 1 , wherein a plurality of the gas storage sections arranged in the first direction communicate with the side surface of the common flow path.

8. 2. The liquid ejection head according to claim 1, wherein an inlet from the common flow path to the individual flow paths is disposed on an upper surface of the common flow path.

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