Liquid discharge head

Abstract

To secure widths of a common passage and a damper as necessary thereby enabling a plurality of individual channels to be densely disposed in a limited area of a liquid discharge head.SOLUTION: A head 1 includes a first common channel 12A, a second common channel 12B, a plurality of individual channels 13, a first damper 28A, and a second damper 29A. An ink having the same color flows through the first common channel 12A and the second common channel 12B. A length in a second direction D2 of the first common channel 12A is longer than a length in a second direction D2 of the second common channel 12B. A length in the second direction D2 of the first damper 28A is longer than a length in the second direction D2 of the second damper 29A.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head having a plurality of individual flow paths, a plurality of common flow paths, and a plurality of dampers. [Background technology]

[0002] Patent Document 1 describes an inkjet head (liquid ejection head) that includes a plurality of individual flow paths, each of which includes a nozzle and a pressure chamber communicating with the nozzle, a plurality of manifolds communicating with the plurality of individual flow paths, and a plurality of dampers provided in the plurality of manifolds. Ink of different colors flows through the plurality of manifolds. In addition, because each manifold is provided with a damper, it is possible to absorb and suppress pressure fluctuations of the ink within the manifolds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-273193 Summary of the Invention [Problem to be solved by the invention]

[0004] To improve the image quality of printed materials, nozzle density is often increased. In a single head having multiple manifolds and multiple dampers through which ink of the same color flows, increasing nozzle density without changing the planar size of the head can be achieved by reducing the width of each manifold to ensure sufficient nozzle placement area. However, reducing the manifold width reduces the amount of ink flowing through the manifold, potentially resulting in poor ink supply to the nozzles. Furthermore, reducing the damper width in accordance with the manifold width makes it difficult to effectively absorb pressure vibrations generated in the ink within the manifold. These pressure vibrations affect the ink in the multiple pressure chambers, resulting in variations in ink ejection characteristics among the multiple nozzles.

[0005] Therefore, an object of the present invention is to provide a liquid ejection head that can ensure the width of the common flow path and damper as needed and can arrange multiple individual flow paths at high density within the limited area of ​​the liquid ejection head. [Means for solving the problem]

[0006] The liquid ejection head of the present invention comprises a first common flow path extending in a first direction perpendicular to the vertical direction, a second common flow path extending in the first direction, a nozzle, and a plurality of individual flow paths each including a pressure chamber communicating with the nozzle, wherein the first individual flow paths each communicate with the first common flow path and the second individual flow paths each communicate with the second common flow path, a first damper arranged along the bottom surface of the first common flow path to absorb pressure fluctuations of the liquid in the first common flow path, and a second damper arranged along the bottom surface of the second common flow path to absorb pressure fluctuations of the liquid in the second common flow path, wherein liquid of the same color flows through the first common flow path and the second common flow path, and the length of the first common flow path in the second direction perpendicular to both the first direction and the vertical direction is greater than the length of the second common flow path in the second direction, and the length of the first damper in the second direction is greater than the length of the second damper in the second direction. [Effects of the Invention]

[0007] According to the liquid ejection head of the present invention, the width (length in the second direction) of the first common flow path is larger than the width of the second common flow path, allowing the first common flow path to circulate more liquid of the same color than the second common flow path. For example, even if a large amount of liquid is supplied from the first common flow path to the first individual flow path, such as when a large amount of liquid is ejected from the nozzles of the first individual flow paths, it is possible to prevent a shortage of liquid supply to the first individual flow paths. Furthermore, the first damper is larger than the second damper in accordance with the width of the first common flow path. Therefore, when a large amount of liquid is ejected from the nozzles of the first individual flow paths, the first damper can effectively absorb pressure fluctuations caused by the flow of liquid in the first common flow path. In this way, by making the width of the first common flow path larger than that of the second common flow path and the width of the first damper larger than that of the second damper, it is not necessary to unnecessarily increase the width of the second common flow path or the width of the second damper. Therefore, it is possible to ensure the widths of the first common flow path and the first damper as needed and to arrange multiple individual flow paths (nozzles) at high density within a limited area of ​​the liquid ejection head. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view of a printer including a head according to a first 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] 4 is an enlarged view of a region IV shown in FIG. 3 on the upper surface of the flow path member. [Figure 5] 5A is a cross-sectional view of the head taken along line VA-VA in FIG. 4, and FIG. 5B is a cross-sectional view of the head taken along line VB-VB in FIG. [Figure 6] 5A is a cross-sectional view of the head taken along line VIA-VIA in FIG. 4, and FIG. 5B is a cross-sectional view of the head taken along line VIB-VIB in FIG. [Figure 7] 6A is a cross-sectional view of the head taken along line VIIA-VIIA in FIG. 4, and FIG. 6B is a cross-sectional view of the head taken along line VIIB-VIIB in FIG. [Figure 8] FIG. 10 is a plan view of a head according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a plan view of a head according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a plan view of a main part of a flow path member of a head according to a modified example of the present invention. [Figure 11] 10A and 10B are partial cross-sectional views of a head according to a fourth embodiment of the present invention, in which (a) shows a fifth individual flow path and (b) shows a seventh individual flow path. [Figure 12] 10A and 10B are partial cross-sectional views of a head according to a fourth embodiment of the present invention, in which (a) shows a first individual flow path and (b) shows a second individual flow path. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment First, referring to Figure 1, the overall configuration of a printer 100 equipped with a head 1 according to a first 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 aligned with 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.

[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 a first direction D1. The length of the heads 1 in the first direction D1 is longer than the length of the heads 1 in a second direction D2. In addition, ink of the same color (e.g., black) is supplied to each head 1. The printer 100 in this embodiment is a monochrome printer.

[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 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 programs and data stored in the ROM 5B and RAM 5C, based on data input from an external device. 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, two supply ports 111 and two return ports 112 are opened in the upper surface (surface) 21A of the flow path member 21. These supply ports 111 and return ports 112 are arranged at one end of the flow path member 21 in the first direction D1. The two return ports 112 are arranged between the two supply ports 111 in the second direction D2. The supply ports 111 and return ports 112 are connected to ink tanks via tubes. The flow path member 21 has two first common flow paths 12A, two second common flow paths 12B, a plurality of individual flow paths 13, two first damper chambers 28, and two second damper chambers 29.

[0019] The two first common flow paths 12A and the two second common flow paths 12B are aligned in the second direction D2 and extend in the first direction D1. The two second common flow paths 12B are disposed between the two first common flow paths 12A in the second direction D2. The length of the first common flow path 12A in the second direction D2 is longer than the length of the second common flow path 12B in the second direction D2, and the cross-sectional area of ​​the first common flow path 12A perpendicular to the first direction D1 is larger than the cross-sectional area of ​​the second common flow path 12B perpendicular to the first direction D1. The volume of the first common flow path 12A is larger than the volume of the second common flow path 12B.

[0020] A supply port 111 is connected to one end of each first common flow path 12A in the first direction D1. A return port 112 is connected to one end of each second common flow path 12B in the first direction D1. The first common flow path 12A and the second common flow path 12B that are adjacent to each other in one side of the second direction D2 communicate with each other at the other end in the first direction D1 via a communicating flow path 12C. The first common flow path 12A and the second common flow path 12B that are adjacent to each other in the other side of the second direction D2 communicate with each other at the other end in the first direction D1 via a communicating flow path 12D. The two first common flow paths 12A and the two second common flow paths 12B communicate with the ink tank via the supply port 111 and the return port 112, and also communicate with the plurality of individual flow paths 13.

[0021] The two first damper chambers 28 are disposed below the two first common flow paths 12A, one each. The two first damper chambers 28 also extend in the first direction D1. The two second damper chambers 29 are disposed below the two second common flow paths 12B, one each. The two second damper chambers 29 also extend in the first direction D1.

[0022] 3 to 7, the individual flow paths 13 include nozzles 15, pressure chambers 16, communication flow paths 17, connection flow paths 18, and upper and lower flow paths 19. One end of the upper and lower flow paths 19 communicates with the nozzles 15, and the other end communicates with the communication flow path 17. One end of the communication flow path 17 communicates with the upper and lower flow paths 19, and the other end communicates with the pressure chambers 16. One end of the connection flow path 18 communicates with the common flow path 12, and the other end communicates with the pressure chambers 16.

[0023] 5, the flow path member 21 includes eleven plates 121 to 131. The flow path member 21 may be configured with 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. As shown in FIGS. 5 and 6, the nozzles 15 have a shape that tapers downward. In this embodiment, the diameters of the nozzles 15 (opening diameters on the lower surface of the plate 131) are all the same.

[0025] The first common flow path 12A and the second common flow path 12B are formed by connecting holes formed in the three plates 127 to 129. That is, the length of the first common flow path 12A in the up-down direction D3 is the same as the length of the second common flow path 12B in the up-down direction D3.

[0026] The communicating channels 12C and 12D are also formed by interconnecting holes formed in the three plates 127 to 129. Note that the communicating channels 12C and 12D may be formed by holes formed in one or two of the three plates 127 to 129.

[0027] The first damper chamber 28 is formed by a recess formed in the plate 130 being blocked by the plate 131. The bottom of the first damper chamber 28 of the plate 130, which is sandwiched between the first damper chamber 28 and the first common flow path 12A, functions as a first damper 28A that absorbs pressure fluctuations of the ink in the first common flow path 12A. In other words, the first damper 28A is disposed along the bottom surface of the first common flow path 12A. Furthermore, even if pressure generated in a pressure chamber 16 when ink is ejected from the nozzle 15 is transmitted to the first common flow path 12A, the first damper 28A attenuates the pressure by elastically deforming, thereby preventing the pressure from being transmitted to other pressure chambers 16 (so-called crosstalk).

[0028] 7, the second damper chamber 29 is also formed by blocking a recess formed in a plate 130 with a plate 131. The bottom of the second damper chamber 29 of the plate 130, which is sandwiched between the second damper chamber 29 and the second common flow path 12B, functions as a second damper 29A that absorbs pressure fluctuations of the ink in the second common flow path 12B. In other words, the second damper 29A is disposed along the bottom surface of the second common flow path 12B. Furthermore, even if pressure generated in a pressure chamber 16 when ink is ejected from a nozzle 15 is transmitted to the second common flow path 12B, the second damper 29A elastically deforms to attenuate the pressure, thereby preventing the pressure from being transmitted to other pressure chambers 16 (so-called crosstalk).

[0029] As shown in Figure 3, the multiple individual flow paths 13 are arranged in a first direction D1 to form 12 individual flow path rows 14R. These individual flow path rows 14R are aligned in a second direction D2. In each individual flow path row 14R, the multiple nozzles 15 are arranged at a predetermined pitch P in the first direction D1. All of the nozzles 15 are arranged at different positions in the first direction D1. As a result, if the printing resolution at the pitch P is 100 dpi, a printing resolution of 1200 dpi is achieved by all of the nozzles 15.

[0030] Four of the 12 individual flow path arrays 14R correspond to one first common flow path 12A, and two of the 12 individual flow path arrays 14R correspond to one second common flow path 12B. That is, as shown in FIGS. 4 to 6, the first individual flow path arrays 14RA to 14RD, each including the first individual flow paths 13A to 13D, communicate with the same first common flow path 12A. Also, as shown in FIG. 4, the fifth individual flow path array 14RE and the sixth individual flow path array 14RF, each including the fifth individual flow path 13E and the sixth individual flow path 13F, communicate with the same second common flow path 12B. The first individual flow paths 13A to 13D correspond to the "first individual flow path" of the present invention, and the fifth individual flow path 13E and the sixth individual flow path 13F correspond to the "second individual flow path" of the present invention. Furthermore, the first individual flow path array 14RA to the fourth individual flow path array 14RD correspond to the "first individual flow path array" of the present invention, and the fifth individual flow path array 14RE and the sixth individual flow path array 14RF correspond to the "second individual flow path array" of the present invention.

[0031] 4, of the four rows of the first individual flow path array 14RA to the fourth individual flow path array 14RD corresponding to each first common flow path 12A, the first nozzles 15A included in the first individual flow path array 14RA and the second nozzles 15B included in the second individual flow path array 14RB are arranged outside one side (the right side in FIG. 4) of the corresponding first common flow path 12A in the second direction D2. In other words, the first nozzle array 15RA formed by a plurality of first nozzles 15A aligned in the first direction D1 and the second nozzle array 15RB formed by a plurality of second nozzles 15B aligned in the first direction D1 are arranged outside one side of the corresponding first common flow path 12A in the second direction D2.

[0032] Of the four rows of the first individual flow path array 14RA to the fourth individual flow path array 14RD corresponding to each first common flow path 12A, the third nozzles 15C included in the third individual flow path array 14RC and the fourth nozzles 15D included in the fourth individual flow path array 14RD are arranged outside the other side (left side in FIG. 4) of the corresponding first common flow path 12A in the second direction D2. In other words, the third nozzle array 15RC, which is formed by a plurality of third nozzles 15C aligned in the first direction D1, and the fourth nozzle array 15RD, which is formed by a plurality of fourth nozzles 15D aligned in the first direction D1, are arranged outside the other side of the corresponding first common flow path 12A in the second direction D2. The first nozzle array 15RA to the fourth nozzle array 15RD correspond to the "first nozzle array" of the present invention.

[0033] Of the two fifth individual flow path arrays 14RE and six individual flow path arrays 14RF corresponding to each second common flow path 12B, the fifth nozzles 15E included in the fifth individual flow path array 14RE are arranged on one side of the corresponding second common flow path 12B in the second direction D2 (right side in FIG. 4). Of the two fifth individual flow path arrays 14RE and six individual flow path arrays 14RF corresponding to each second common flow path 12B, the sixth nozzles 15F included in the sixth individual flow path array 14RF are arranged on the other side of the corresponding second common flow path 12B in the second direction D2 (left side in FIG. 4). In other words, the fifth nozzle array 15RE, formed by a plurality of fifth nozzles 15E aligned in the first direction D1, is arranged outside one side of the corresponding second common flow path 12B in the second direction D2. The sixth nozzle array 15RF, formed by a plurality of sixth nozzles 15F aligned in the first direction D1, is arranged outside the other side of the corresponding second common flow path 12B in the second direction D2. The fifth nozzle row 15RE and the sixth nozzle row 15RF correspond to the "second nozzle row" of the present invention.

[0034] 4, the first individual flow paths 13A and the second individual flow paths 13B, which are adjacent to each other in the second direction D2 and communicate with the same first common flow path 12A, are spaced apart in the second direction D2 so that the first nozzle 15A overlaps with the second pressure chamber 16B in the vertical direction D3, and the first nozzle 15A and the second nozzle 15B are spaced apart in the first direction D1 by a distance 1 / 12 of the pitch P. The third individual flow path 13C and the fourth individual flow path 13D, which are adjacent to each other in the second direction D2 and communicate with the same first common flow path 12A, are similarly spaced apart in the second direction D2 so that the third nozzle 15C overlaps with the fourth pressure chamber 16D in the vertical direction D3, and the third nozzle 15C and the fourth nozzle 15D are spaced apart in the first direction D1 by a distance 1 / 12 of the pitch P.

[0035] The fifth individual flow path 13E and the sixth individual flow path 13F, which are adjacent in the second direction D2 and communicate with the same second common flow path 12B, are arranged so that the fifth nozzle 15E and the sixth nozzle 15F are spaced apart in the first direction D1 by a distance of 1 / 6 of the pitch P. The two sixth individual flow paths 13F, which are adjacent in the second direction D2 and communicate with different second common flow paths 12B, are arranged so that the sixth nozzles 15F are spaced apart in the first direction D1 by a distance of 1 / 12 of the pitch P.

[0036] Furthermore, the fifth individual flow path 13E and the sixth individual flow path 13F, which are adjacent in the second direction D2 and communicate with different second common flow paths 12B, are arranged such that the fifth nozzle 15E overlaps with the sixth pressure chamber 16F in the vertical direction D3, and the sixth nozzle 15F overlaps with the fifth pressure chamber 16E in the vertical direction D3, and are spaced apart in the second direction D2 by a distance of 1 / 12 of the pitch P in the first direction D1.

[0037] Furthermore, the second individual flow path 13B and the sixth individual flow path 13F, which are adjacent in the second direction D2, are arranged such that the second nozzle 15B overlaps with the sixth pressure chamber 16F in the vertical direction D3, and the sixth nozzle 15F overlaps with the second pressure chamber 16B in the vertical direction D3, and are spaced apart in the second direction D2 by a distance of 1 / 12 of the pitch P in the first direction D1.

[0038] Although not shown in Figure 4, the fifth individual flow path 13E and the fourth individual flow path 13D, which are adjacent to each other in the second direction D2, are arranged so that the fifth nozzle 15E overlaps with the fourth pressure chamber 16D in the vertical direction D3, and the fourth nozzle 15D overlaps with the fifth pressure chamber 16E in the vertical direction D3, and are spaced apart in the second direction D2 by a distance of 1 / 12 of the pitch P between the fifth nozzle 15E and the fourth nozzle 15D in the first direction D1.

[0039] The first individual flow path 13A and the third individual flow path 13C are arranged symmetrically with respect to the midpoint of the line segment connecting the first nozzle 15A and the third nozzle 15C in a plane perpendicular to the up-down direction D3. The second individual flow path 13B and the fourth individual flow path 13D are arranged symmetrically with respect to the midpoint of the line segment connecting the second nozzle 15B and the fourth nozzle 15D in a plane perpendicular to the up-down direction D3.

[0040] The first individual flow path 13A and the fourth individual flow path 13D are also arranged symmetrically with respect to the midpoint of the line segment connecting the first nozzle 15A and the fourth nozzle 15D in a plane perpendicular to the up-down direction D3. The second individual flow path 13B and the third individual flow path 13C are also arranged symmetrically with respect to the midpoint of the line segment connecting the second nozzle 15B and the third nozzle 15C in a plane perpendicular to the up-down direction D3.

[0041] The fifth individual flow path 13E and the sixth individual flow path 13F are also arranged symmetrically with respect to the midpoint of the line segment connecting the fifth nozzle 15E and the sixth nozzle 15F in a plane perpendicular to the up-down direction D3. The fifth individual flow path 13E and the third individual flow path 13C or the fourth individual flow path 13D are also arranged symmetrically with respect to the midpoint of the line segment connecting the fifth nozzle 15E and the third nozzle 15C or the fourth nozzle 15D in a plane perpendicular to the up-down direction D3. The sixth individual flow path 13F and the first individual flow path 13A or the second individual flow path 13B are also arranged symmetrically with respect to the midpoint of the line segment connecting the sixth nozzle 15F and the first nozzle 15A or the second nozzle 15B in a plane perpendicular to the up-down direction D3.

[0042] The detailed configuration of the first individual flow path 13A will be described below.

[0043] 5(a), the first individual flow path 13A includes a first nozzle 15A, a first pressure chamber 16A, a communication flow path 17A, a connection flow path 18A, and an upper and lower flow path 19A. As shown in FIG. 4, the first pressure chamber 16A overlaps in the second direction D2 with a second pressure chamber 16B included in a second individual flow path 13B adjacent to the first individual flow path 13A.

[0044] As shown in Fig. 5(a), the upper and lower flow paths 19A extend upward from the first nozzle 15A in the vertical direction D3. As shown in Fig. 5(a), the upper and lower flow paths 19A are formed by interconnecting holes formed in five plates 126 to 130, and have a diameter larger than that of the first nozzle 15A. The first nozzle 15A is disposed closer to the corresponding first common flow path 12A in the second direction D2 than the second nozzle 15B included in the second individual flow path 13B.

[0045] The communication flow path 17A includes a first portion 17A1 having one end connected to the first pressure chamber 16A, and a second portion 17A2 having one end connected to the other end of the first portion 17A1 and the other end connected to the up-down flow path 19A. The first portion 17A1 is formed by interconnecting holes formed in three plates 122 to 124. The three holes constituting the first portion 17A1 are formed so that their hole diameters decrease toward the plates 122 to 124. In other words, the cross-sectional area of ​​the first portion 17A1 decreases stepwise from the first pressure chamber 16A downward. The second portion 17A2 is formed by holes formed in the plate 125, as shown in FIG. 5(a).

[0046] 5(a), the connection flow path 18A has a first portion 18A1 and a second portion 18A2. The first portion 18A1 is formed by interconnecting holes formed in the three plates 124 to 126, and is connected to the upper end of the first common flow path 12A.

[0047] The second portion 18A2 has a horizontal portion 18A2A connected to the upper end of the first portion 18A1 and a vertical portion 18A2B connected to the first pressure chamber 16A. The horizontal portion 18A2A is a hole formed in the plate 123 and extends from the upper end of the first portion 18A1 toward the first pressure chamber 16A along the second direction D2. The horizontal portion 18A2A also has a throttle portion 18A2C that throttles the flow rate of the liquid. The throttle portion 18A2C is formed in a central portion in the second direction D2, and its flow path width (length in a direction perpendicular to the second direction D2) is smaller than the flow path width of the first portion 18A1.

[0048] 5(a), the vertical portion 18A2B is a hole formed in the plate 122, and extends upward from the end of the horizontal portion 18A2A on the first pressure chamber 16A side toward the first pressure chamber 16A. In this way, the second portion 18A2 is formed by connecting the holes formed in the two plates 122 and 123 to each other.

[0049] As described above, the second individual flow path 13B, the third individual flow path 13C, and the fourth individual flow path 13D have the same configuration as the first individual flow path 13A, and therefore detailed configurations thereof will not be described. As shown in Fig. 5(b), the second individual flow path 13B includes a second nozzle 15B, a second pressure chamber 16B, a communication flow path 17B, a first portion 17B1, a second portion 17B2, a connection flow path 18B, a first portion 18B1, a second portion 18B2, a horizontal portion 18B2A, a vertical portion 18B2B, a throttle portion 18B2C, and an upper and lower flow paths 19B.

[0050] 6(a), the third individual flow path 13C includes a third nozzle 15C, a third pressure chamber 16C, a communicating flow path 17C, a first portion 17C1, a second portion 17C2, a connecting flow path 18C, a first portion 18C1, a second portion 18C2, a horizontal portion 18C2A, a vertical portion 18C2B, a throttle portion 18C2C, and an upper and lower flow path 19C. As shown in FIG. 6(b), the fourth individual flow path 13D includes a fourth nozzle 15D, a fourth pressure chamber 16D, a communicating flow path 17D, a first portion 17D1, a second portion 17D2, a connecting flow path 18D, a first portion 18D1, a second portion 18D2, a horizontal portion 18D2A, a vertical portion 18D2B, a throttle portion 18D2C, and an upper and lower flow path 19D.

[0051] 4, the third pressure chamber 16C overlaps with the fourth pressure chamber 16D in the second direction D2. More specifically, the first pressure chamber 16A to the fourth pressure chamber 16D included in each of the four first individual flow paths 13A to the fourth individual flow paths 13D overlap in the second direction D2. The third nozzle 15C is disposed closer to the corresponding first common flow path 12A than the fourth nozzle 15D in the second direction D2.

[0052] 7A, the fifth individual flow path 13E includes a fifth nozzle 15E, a fifth pressure chamber 16E, a communication flow path 17E, a first portion 17E1, a second portion 17E2, a connection flow path 18E, a first portion 18E1, a second portion 18E2, a horizontal portion 18E2A, a vertical portion 18E2B, a throttle portion 18E2C, and upper and lower flow paths 19E. 7(b), the sixth individual flow path 13F includes a sixth nozzle 15F, a sixth pressure chamber 16F, a communication flow path 17F, a first portion 17F1, a second portion 17F2, a connection flow path 18F, a first portion 18F1, a second portion 18F2, a horizontal portion 18F2A, a vertical portion 18F2B, a throttle portion 18F2C, and an upper and lower flow path 19F. As shown in FIG. 4, the fifth pressure chamber 16E and the sixth pressure chamber 16F, which communicate with the same second common flow path 12B and are adjacent to each other in the second direction D2, overlap in the second direction D2.

[0053] 2 is driven under the control of the control unit 5, ink in the ink tank is supplied to the first common flow path 12A via the supply port 111, flows from the first common flow path 12A to the second common flow path 12B via the communicating flow paths 12C and 12D, and is distributed to the multiple individual flow paths 13 from the first common flow path 12A and the second common flow path 12B. More specifically, the pump 10 communicates with the supply port 111 and is controlled by the control unit 5 so as to apply a first pressure (negative pressure) to the ink in the supply port 111. On the other hand, the pump 11 communicates with the return port 112 and is controlled by the control unit 5 so as to apply a second pressure (negative pressure) smaller than the first pressure to the return port 112. Due to this pressure difference, the ink supplied from the supply port 111 flows through the first common flow path 12A from one end to the other end in the first direction D1. Then, the ink that has flowed into the second common flow path 12B via the communicating flow paths 12C and 12D flows in the second common flow path 12B from the other end to one end in the first direction D1, and reaches the return port 112. The ink that has reached the return port 112 is returned to the ink tank via a tube.

[0054] 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 the upper and lower flow paths 19 and be ejected as ink droplets from the nozzle 15.

[0055] 3 and 5 to 7, 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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 embodiment, either a first drive pulse signal that causes a large droplet of ink to be ejected from the nozzle 15 or a second drive pulse signal that causes a small droplet of ink, which contains less ink than the large droplet, to be ejected from the nozzle 15 is generated. The first drive pulse signal has a larger number of pulses than the second drive pulse signal, but may also have a higher voltage. The first drive pulse signal or the second drive pulse signal is selected depending on the desired amount of ink to be ejected from the nozzle 15. When the actuator unit 35 is driven in this manner and pressure is applied to the ink in the pressure chamber 16, ink droplets are ejected from the nozzle 15 through the communicating flow path 17.

[0061] As described above, in the head 1 of this embodiment, the length (width) of the first common flow path 12A in the second direction D2 is greater than the length (width) of the second common flow path 12B, and therefore the first common flow path 12A can circulate more ink of the same color than the second common flow path 12B. For example, when a large amount of ink is ejected from the first nozzles 15A to 15D of the first individual flow paths 13A to 13D, even if a large amount of ink is supplied from the first common flow path 12A to the first individual flow paths 13A to 13D, it is possible to prevent a shortage of ink supply to the first individual flow paths 13A to 13D.

[0062] Furthermore, the first damper 28A is larger than the second damper 29A in accordance with the width of the first common flow path 12A. Therefore, by ejecting a large amount of ink from the first nozzles 15A to 15D of the first individual flow paths 13A to 13D, the first damper 28A can effectively absorb pressure fluctuations caused by the ink flow in the first common flow path 12A. By making the width of the first common flow path 12A larger than that of the second common flow path 12B and the width of the first damper 28A larger than that of the second damper 29A, it is not necessary to unnecessarily increase the width of the second common flow path 12B or the width of the second damper 29A. Therefore, it is possible to secure the widths of the first common flow path 12A and the first damper 28A as needed and to arrange multiple individual flow paths 13 (nozzles 15) at high density within a limited area of ​​the head 1.

[0063] Furthermore, if a head is configured by providing two pairs of the second common flow path 12B and two pairs of the fifth individual flow path array 14RE and the sixth individual flow path array 14RF, without providing a pair of the first common flow path 12A and four rows of the first to fourth individual flow path arrays 14RA to 14RD, it is possible to achieve a high density of the nozzles 15, but the length (width) of the head in the second direction D2 becomes large. However, in this embodiment, it is possible to achieve a high density of the nozzles 15 within a limited area of ​​the head 1 while suppressing an increase in the length of the head 1 in the second direction D2.

[0064] The number of individual flow paths 13 (first individual flow paths 13A to fourth individual flow paths 13D) communicating with the first common flow path 12A is greater than the number of individual flow paths 13 (fifth individual flow paths 13E, sixth individual flow path 13F) communicating with the second common flow path 12B. Even if a large number of first individual flow paths 13A to fourth individual flow paths 13D are provided, the first common flow path 12A can circulate a large amount of ink, and therefore ink can be effectively supplied to the first individual flow paths 13A to fourth individual flow paths 13D.

[0065] Furthermore, by providing the communicating channels 12C and 12D, the pressure fluctuation of the ink occurring in the second common channel 12B can also be absorbed by the first damper 28A via the communicating channels 12C and 12D and the first common channel 12A.

[0066] Furthermore, of the four nozzles 15 included in the individual flow paths 13 communicating with the first common flow path 12A, the first nozzle row 15RA to the fourth nozzle row 15RD, the first nozzle row 15RA and the second nozzle row 15RB are arranged on one side of the first common flow path 12A in the second direction D2, and the third nozzle row 15RC and the fourth nozzle row 15RD are arranged on the other side of the first common flow path 12A in the second direction D2. This allows the nozzles 15 included in the first individual flow paths 13A to the fourth individual flow paths 13D to be arranged at high density.

[0067] Second Embodiment Next, a head 1 according to a second embodiment of the present invention will be described with reference to FIG. 8. In the head 1 according to this embodiment, the other ends of two first common flow paths 12A in the first direction D1 are connected to each other by a communication flow path 212C, and the other ends of two second common flow paths 12B in the first direction D1 are connected to each other by a communication flow path 212D. A supply port 111 is connected to one end of one of the two first common flow paths 12A, and a return port 112 is connected to one end of the other first common flow path 12A. A supply port 111 is connected to one end of one of the two second common flow paths 12B, and a return port 112 is connected to one end of the other second common flow path 12B. The head 1 according to this embodiment is otherwise similar to the first embodiment. Components similar to those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0068] By providing such a communication flow path 212C, it is possible to circulate ink in order to suppress variations in ink temperature and viscosity between the first common flow paths 12A. Furthermore, by connecting the first common flow paths 12A to each other, it is possible to suppress the propagation of large pressure fluctuations caused by ejecting a large amount of ink from the nozzles 15 of the first individual flow paths 13A to the fourth individual flow paths 13D to the second common flow path 12B. This makes it possible to stabilize the ejection from the nozzles 15 of the fifth individual flow path 13E and the sixth individual flow path 13F.

[0069] Furthermore, by providing the communicating flow path 212D, it is possible to circulate ink in order to suppress variations in ink temperature and viscosity between the second common flow paths 12B. Furthermore, by communicating with the first common flow path 12A independently, it is possible to suppress large pressure fluctuations caused by ejecting a large amount of ink from the nozzles 15 of the first individual flow path 13A to the fourth individual flow path 13D from propagating to the second common flow path 12B, thereby stabilizing ejection from the nozzles 15 of the fifth individual flow path 13E and the sixth individual flow path 13F.

[0070] <Third embodiment> Next, a head 1 according to a third embodiment of the present invention will be described with reference to FIG. 9. In the head 1 according to this embodiment, two first common flow paths 12A are arranged on one side in the second direction D2, and two second common flow paths 12B are arranged on the other side. The other ends of the two first common flow paths 12A in the first direction D1 are connected to each other by a communicating flow path 312C, and the other ends of the two second common flow paths 12B in the first direction D1 are connected to each other by a communicating flow path 312D. A supply port 111 is connected to one end of one of the two first common flow paths 12A, and a return port 112 is connected to one end of the other first common flow path 12A. A supply port 111 is connected to one end of one of the two second common flow paths 12B, and a return port 112 is connected to one end of the other second common flow path 12B. The head 1 according to this embodiment is otherwise similar to that according to the first embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0071] In the head 1 of this embodiment, two first common flow paths 12A are arranged adjacent to each other in the second direction D2 without a second common flow path 12B between them. This allows the length of the communicating flow path 312C in the second direction D2 to be shortened. Furthermore, because the length of the communicating flow path 312C is short, the flow path resistance in the communicating flow path 312C is also small. This makes it easier to circulate ink from one first common flow path 12A to the other first common flow path 12A via the communicating flow path 312C.

[0072] Furthermore, in the head 1, two second common flow paths 12B are arranged adjacent to each other in the second direction D2 without a first common flow path 12A being arranged between them. This allows the length of the communicating flow path 312D in the second direction D2 to be shortened. Furthermore, because the length of the communicating flow path 312D is short, the flow path resistance in the communicating flow path 312D is also small. This makes it easier to circulate ink from one second common flow path 12B to the other second common flow path 12B via the communicating flow path 312D. Note that the head 1 in this embodiment also has the same effects as the second embodiment in a configuration similar to that of the second embodiment.

[0073] 10, four individual flow path arrays 14R may correspond to one second common flow path 12B. That is, four rows of the fifth individual flow path array 14RE to eighth individual flow path array 14RH are each composed of a plurality of individual flow paths 13 arranged in the first direction D1. The fifth individual flow path array 14RE to eighth individual flow path array 14RH each include a fifth individual flow path 13E to eighth individual flow path 13H that communicate with the same second common flow path 12B. The fifth individual flow path 13E to eighth individual flow path 13H correspond to the "second individual flow path" of the present invention, and the fifth individual flow path array 14RE to eighth individual flow path array 14RH correspond to the "second individual flow path array" of the present invention.

[0074] In this embodiment, the fifth individual flow path 13E to the eighth individual flow path 13H have the same flow path configuration, including the flow path shape and size. The seventh individual flow path 13G includes a seventh nozzle 15G, a seventh pressure chamber 16G, a communication flow path 17G, a connection flow path 18G, and an upper and lower flow path 19G. As shown in Fig. 10, the eighth individual flow path 13H includes an eighth nozzle 15H, an eighth pressure chamber 16H, a communication flow path 17H, a connection flow path 18H, and an upper and lower flow path 19H.

[0075] The fifth individual flow path 13E and the seventh individual flow path 13G, which are adjacent to each other in the second direction D2 and communicate with the same second common flow path 12B, are arranged to be spaced apart in the second direction D2 so that the fifth nozzle 15E overlaps with the seventh pressure chamber 16G in the vertical direction D3. The sixth individual flow path 13F and the eighth individual flow path 13H, which are adjacent to each other in the second direction D2 and communicate with the same second common flow path 12B, are arranged to be spaced apart in the second direction D2 so that the sixth nozzle 15F overlaps with the eighth pressure chamber 16H in the vertical direction D3.

[0076] Of the four fifth to eighth individual flow path rows 14RE to 14RH corresponding to the second common flow path 12B, the fifth nozzle 15E included in the fifth individual flow path row 14RE and the seventh nozzle 15G included in the seventh individual flow path row 14RG are arranged outside one side (right side in FIG. 10) of the corresponding second common flow path 12B in the second direction D2. In other words, the seventh nozzle row 15RG, which is formed by the fifth nozzle row 15RE and the multiple seventh nozzles 15G lined up in the first direction D1, is arranged outside one side of the corresponding second common flow path 12B in the second direction D2.

[0077] Of the four fifth individual flow path arrays 14RE to 8th individual flow path arrays 14RH corresponding to the second common flow path 12B, the sixth nozzle 15F included in the sixth individual flow path array 14RF and the eighth nozzle 15H included in the eighth individual flow path array 14RH are arranged outside the other side (left side in FIG. 10) of the corresponding second common flow path 12B in the second direction D2. In other words, the eighth nozzle array 15RH, which is formed by arranging the sixth nozzle array 15RF and a plurality of eighth nozzles 15H in the first direction D1, is arranged outside the other side of the corresponding second common flow path 12B in the second direction D2. The fifth nozzle array 15RE to the eighth nozzle array 15RH correspond to the "second nozzle array" of the present invention.

[0078] Of the four nozzle rows, the fifth nozzle row 15RE to the eighth nozzle row 15RH, the fifth nozzle row 15RE and the seventh nozzle row 15RG are arranged on one side of the second common flow path 12B in the second direction D2, and the sixth nozzle row 15RF and the eighth nozzle row 15RH are arranged on the other side of the second common flow path 12B in the second direction D2. This allows the nozzles 15 included in the fifth individual flow paths 13E to the eighth individual flow paths 13H to be arranged at high density.

[0079] <Fourth embodiment> Next, a head 1 according to a fourth embodiment of the present invention will be described with reference to Figures 11 and 12. The head 1 according to this embodiment has a first common flow path 412A and a second common flow path 412B arranged to overlap in the vertical direction D3, and has a flow path member 420 in which four nozzle rows 15R are arranged on one outer side of each of the common flow paths 412A, 412B in the second direction D2. The head 1 according to this embodiment is otherwise the same as that according to the first embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0080] 11, the flow path member 420 includes thirteen plates 421 to 433. A plurality of pressure chambers 16 are formed in the uppermost plate 421, and a plurality of nozzles 15 are formed in the lowermost plate 433.

[0081] The first common flow path 412A is formed by interconnecting holes formed in the two plates 430, 431. The second common flow path 412B is formed by holes formed in the plate 127. The length of the first common flow path 412A in the second direction D2 is greater than the length of the second common flow path 412B in the second direction D2. Furthermore, the length of the first common flow path 412A in the up-down direction D3 is greater than the length of the second common flow path 412B in the up-down direction D3. In other words, the cross-sectional area of ​​the first common flow path 412A perpendicular to the first direction D1 is greater than the cross-sectional area of ​​the second common flow path 412B perpendicular to the first direction D1, and the volume of the first common flow path 412A is greater than the volume of the second common flow path 412B.

[0082] The first damper chamber 28 is formed by closing a recess formed in the plate 432 with the plate 433. The portion of the plate 432 at the bottom of the first damper chamber 28, which is sandwiched between the first damper chamber 28 and the first common flow path 412A, functions as the first damper 28A. In other words, the first damper 28A is disposed on the bottom surface of the first common flow path 412A, and absorbs pressure fluctuations of the ink in the first common flow path 412A.

[0083] The second damper chamber 29 is also formed by closing a recess formed in the plate 428 with the plate 429. The portion of the plate 428 at the bottom of the second damper chamber 29, which is sandwiched between the second damper chamber 29 and the second common flow path 412B, functions as the second damper 29A. In other words, the second damper 29A is disposed on the bottom surface of the second common flow path 412B, and absorbs pressure fluctuations of the ink in the second common flow path 412B.

[0084] The multiple individual flow paths 13 form four individual flow path arrays 14R. In this embodiment, the four individual flow path arrays 14R are formed by a first individual flow path array 14RA, a second individual flow path array 14RB, a fifth individual flow path array 14RE, and a seventh individual flow path array 14RG. In each individual flow path array 14R, the multiple nozzles 15 are arranged at a predetermined pitch P in the first direction D1. The center of a first nozzle 15A included in the first individual flow path array 14RA and the center of a fifth nozzle 15E included in the fifth individual flow path array 14RE are arranged to overlap in the second direction D2. The center of a second nozzle 15B included in the second individual flow path array 14RB and the center of a seventh nozzle 15G included in the seventh individual flow path array 14RG are arranged to overlap in the second direction D2.

[0085] The four individual flow path arrays 14R correspond to two arrays each of the first common flow path 412A and the second common flow path 412B. More specifically, the first individual flow path array 14RA and the second individual flow path array 14RB correspond to the first common flow path 412A, and the fifth individual flow path array 14RE and the seventh individual flow path array 14RG correspond to the second common flow path 412B. As shown in FIG. 11 , the fifth individual flow path array 14RE and the seventh individual flow path array 14RG each include a fifth individual flow path 13E and a seventh individual flow path 13G, which communicate with the second common flow path 412B. As shown in FIG. 12 , the first individual flow path array 14RA and the second individual flow path array 14RB each include a first individual flow path 13A and a second individual flow path 13B, which communicate with the first common flow path 412A. The first individual flow path 13A and the second individual flow path 13B correspond to the "first individual flow path" of the present invention, and the fifth individual flow path 13E and the seventh individual flow path 13G correspond to the "second individual flow path" of the present invention. Furthermore, the first individual flow path array 14RA and the second individual flow path array 14RB correspond to the "first individual flow path array" of the present invention, and the fifth individual flow path array 14RE and the seventh individual flow path array 14RG correspond to the "second individual flow path array" of the present invention.

[0086] As shown in Figures 11 and 12, the first nozzle row 15RA formed by a plurality of first nozzles 15A, the second nozzle row 15RB formed by a plurality of second nozzles 15B, the fifth nozzle row 15RE formed by a plurality of fifth nozzles 15E, and the seventh nozzle row 15RG formed by a plurality of seventh nozzles 15G are arranged on one side (right side) outside of the first common flow path 412A in the second direction D2.

[0087] 11, the fifth individual flow path 13E included in the fifth individual flow path array 14RE and the seventh individual flow path 13G included in the seventh individual flow path array 14RG have the same flow path configuration, including flow path shape and size. Moreover, the fifth individual flow path 13E and the seventh individual flow path 13G in this embodiment are the same as those in the modified example described above, except that the vertical flow paths 19E, 19G are longer in length in the vertical direction D3 than the vertical flow paths 19E, 19G in the modified example described above.

[0088] 12, the first individual flow path 13A included in the first individual flow path array 14RA and the second individual flow path 13B included in the second individual flow path array 14RB have the same flow path configuration, including the flow path shape and size, except for the lengths of the horizontal portions 18A2A and 18B2A. Furthermore, in the first individual flow path 13A and the second individual flow path 13B of this embodiment, the first portions 18A1 and 18B1 and the up-down flow paths 19A and 19B are longer in the up-down direction D3 than the first portions 18A1 and 18B1 and the up-down flow paths 19A and 19B of the first embodiment, and the horizontal portions 18A2A and 18B2A are longer in the horizontal extension direction than the horizontal portions 18A2A and 18B2A of the first embodiment. Furthermore, the diameter L1 (opening diameter at the bottom surface of the plate 433) of the first nozzle 15A and the second nozzle 15B of this embodiment is larger than the diameter of the first nozzle 15A and the second nozzle 15B of the first embodiment. That is, the diameter L1 of the first nozzle 15A and the second nozzle 15B in this embodiment is larger than the diameter L2 (opening diameter on the lower surface of the plate 433) of the fifth nozzle 15E and the seventh nozzle 15G. The first individual flow path 13A and the second individual flow path 13B in this embodiment are otherwise the same as those in the first embodiment.

[0089] In this embodiment, the same effects can be obtained in a configuration similar to that of the above-described embodiments and modified examples. Furthermore, the second common flow path 412B and the second damper 29A are arranged above the first common flow path 412A and at a position overlapping with the first common flow path 412A in the up-down direction D3. This allows the head 1 to be made smaller in size in the second direction D2 than if the first common flow path 412A and the second common flow path 412B were arranged side by side in the second direction D2.

[0090] Furthermore, the center of the first nozzle 15A and the center of the fifth nozzle 15E are arranged to overlap in the second direction D2, and the center of the second nozzle 15B and the center of the seventh nozzle 15G are arranged to overlap in the second direction D2. This makes it possible to make the resolution of an image formed by ink ejected from the multiple first nozzles 15A and the multiple second nozzles 15B the same as the resolution of an image formed by ink ejected from the multiple fifth nozzles 15E and the multiple seventh nozzles 15G.

[0091] Furthermore, the diameters of the first nozzle 15A and the second nozzle 15B are larger than the diameters of the fifth nozzle 15E and the seventh nozzle 15G. As a result, even if the actuator member 22 applies the same amount of pressure to each of the first pressure chamber 16A, the second pressure chamber 16B, the fifth pressure chamber 16E, and the seventh pressure chamber 16G, the volume of ink droplets ejected from the first nozzle 15A and the second nozzle 15B is greater than the volume of ink droplets ejected from the fifth nozzle 15E and the seventh nozzle 15G. This is because the larger the nozzle diameter, the weaker the force (e.g., surface tension) that holds the ink in the nozzle portion, allowing more ink to be ejected from the nozzle 15 even with a small amount of pressure. Therefore, even if the volume of ink droplets ejected from the first nozzle 15A and the second nozzle 15B is increased, the pressure generated in the first pressure chamber 16A and the second pressure chamber 16B does not become too large, and residual vibration in the first common flow path 412A is also reduced. As a result, the ejection characteristics from the multiple nozzles 15 are stabilized. Furthermore, even if the volume of ink droplets ejected from the first nozzle 15A and the second nozzle 15B is increased, there is no need to increase the amount of deformation of the actuator member 22 relative to the first pressure chamber 16A and the second pressure chamber 16B. This makes it possible to suppress heat generation by the actuator member 22. Furthermore, even if the volume of ink droplets ejected from the first nozzle 15A and the second nozzle 15B is increased, the first common flow path 412A can circulate a large amount of ink, so ink can be effectively supplied to the first individual flow path 13A and the second individual flow path 13B.

[0092] As a modified example, four nozzle arrays 15R may be arranged on the other outer side of each of the common flow paths 412A and 412B in the second direction D2. That is, each of the common flow paths 412A and 412B may be connected to a plurality of individual flow paths 13 included in four individual flow path arrays 14R. As another modified example, the first common flow path 412A may be connected to a plurality of individual flow paths 13 included in three or more individual flow path arrays 14R, and the second common flow path 412B may be connected to a plurality of individual flow path 13 included in two or less individual flow path arrays 14R. For example, as in the first embodiment, the first common flow path 412A may be associated with four individual flow path arrays 14R, and the second common flow path 412B may be associated with two individual flow path arrays 14R. In this case, all of the nozzles 15 may be offset from one another in the first direction D1. Furthermore, two or more first common flow paths 412A and two or more second common flow paths 412B may be provided.

[0093] 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.

[0094] In each of the above-described embodiments, the number of individual flow path arrays is not particularly limited as long as multiple individual flow paths 13 are connected to each of the common flow paths 12A, 12B, 412A, and 412B. That is, the number of individual flow path arrays corresponding to the first common flow paths 12A and 412A may be equal to or less than the number of individual flow path arrays corresponding to the second common flow paths 12B and 412B. For example, the number of individual flow path arrays 14R corresponding to each first common flow path 12A in the first embodiment may be two. In this case, the amount of ink ejected from the nozzles 15 communicating with the first common flow path 12A may be greater than the amount of ink ejected from the nozzles 15 communicating with the second common flow path 12B. In this case, the nozzles 15 communicating with the first common flow path 12A and the nozzles 15 communicating with the second common flow path 12B may be arranged such that their centers overlap in the second direction D2 or are shifted from each other in the first direction D1.

[0095] Furthermore, if the amount of ink ejected from the individual flow paths 13 connected to the first common flow path 12A, 412A is greater than the amount of ink ejected from the individual flow paths 13 connected to the second common flow path 12B, 412B, the number of individual flow paths 13 connected to the first common flow path 12A, 412A may be less than the number of individual flow paths 13 connected to the second common flow path 12B, 412B.

[0096] In the first to third embodiments described above, the plurality of nozzles 15 communicating with the first common flow path and the plurality of nozzles 15 communicating with the second common flow path may be arranged with their centers overlapping in the second direction D2. In this case, the diameter of the nozzles 15 communicating with the first common flow path may be larger than the diameter of the nozzles 15 communicating with the second common flow path.

[0097] The individual flow paths 13 are not particularly limited and may have any configuration as long as they include the pressure chambers 16 and the nozzles 15 .

[0098] In each of the above-described embodiments, 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.

[0099] The type of liquid ejection head of the present invention is not limited to the line type, but may also be a serial type.

[0100] The object onto which the droplets are ejected is not limited to paper, but may be, for example, a cloth, a substrate, or plastic.

[0101] The liquid supplied to the head may be a liquid other than ink as long as it is of the same color.

[0102] 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]

[0103] 1 head 12A, 412A First common flow path 12B, 412B Second common flow path 12C, 12D, 212C, 212D, 312C, 312D Connecting flow path 13 Individual flow path 13A to 13H 1st individual flow path to 8th individual flow path 14RA~14RHD 1st individual channel row to 8th individual channel row 15 nozzles 15A~15H 1st nozzle~8th nozzle 15RA~15RH 1st nozzle row to 8th nozzle row 16 Pressure Chamber 16A~16H 1st pressure chamber to 8th pressure chamber 21 Flow path member 22 Actuator member 28A First Damper 29A Second damper D1 1st direction D2 2nd direction D3 Up and down direction

Claims

1. a first common flow path extending in a first direction perpendicular to the up-down direction; a second common flow path extending in the first direction; a plurality of individual flow paths each including a nozzle and a pressure chamber communicating with the nozzle, the plurality of first individual flow paths each communicating with the first common flow path and a plurality of second individual flow paths each communicating with the second common flow path; a first damper disposed along a bottom surface of the first common flow path and configured to absorb pressure fluctuations of the liquid in the first common flow path; a second damper disposed along a bottom surface of the second common flow path and absorbing pressure fluctuations of the liquid in the second common flow path; The first common flow path and the second common flow path are flowing with liquids of the same color, a length of the first common flow path in a second direction perpendicular to both the first direction and the up-down direction is greater than a length of the second common flow path in the second direction; A liquid ejection head, wherein the length of the first damper in the second direction is greater than the length of the second damper in the second direction.

2. 2. The liquid ejection head according to claim 1, wherein the number of the first individual flow paths is greater than the number of the second individual flow paths.

3. 2. The liquid ejection head according to claim 1, further comprising a communication flow path that connects the first common flow path and the second common flow path.

4. a plurality of the first common flow paths and a plurality of the first dampers, 2. The liquid ejection head according to claim 1, further comprising a communication flow path that connects the plurality of first common flow paths to one another.

5. 5. The liquid ejection head according to claim 4, wherein the plurality of first common flow paths are arranged adjacent to each other in the second direction.

6. a plurality of the second common flow paths and a plurality of the second dampers, 2. The liquid ejection head according to claim 1, further comprising a communication flow path that connects the plurality of second common flow paths to one another.

7. 7. The liquid ejection head according to claim 6, wherein the plurality of second common flow paths are arranged adjacent to each other in the second direction.

8. The liquid ejection head according to claim 1 , wherein the second common flow path and the second damper are arranged above the first common flow path and at a position overlapping the first common flow path in the vertical direction.

9. a plurality of first individual flow path rows, each of which has the plurality of first individual flow paths arranged in the first direction, are arranged in the second direction; The liquid ejection head according to claim 1, characterized in that, in the second direction, a plurality of first nozzle rows are arranged outside at least one of the first common flow paths, each row being formed by arranging a plurality of the nozzles included in the plurality of first individual flow path rows in the first direction.

10. a plurality of second individual flow path rows, each of which has the plurality of second individual flow paths arranged in the first direction, are arranged in the second direction; A liquid ejection head as described in claim 9, characterized in that in the second direction, a plurality of second nozzle rows are arranged outside at least one of the second common flow paths, where the plurality of nozzles included in the plurality of second individual flow path rows are arranged in the first direction.

11. the plurality of first individual flow paths and the plurality of second individual flow paths are respectively arranged in the first direction, a distance in the first direction between nozzles included in two of the first individual flow paths adjacent to each other in the first direction is equal to a distance in the first direction between nozzles included in two of the second individual flow paths adjacent to each other in the first direction, The liquid ejection head according to claim 1 , wherein the center of the nozzle included in the first individual flow path and the center of the nozzle included in the second individual flow path overlap in the second direction.

12. 2. The liquid ejection head according to claim 1, wherein the diameter of the nozzle included in the first individual flow path is larger than the diameter of the nozzle included in the second individual flow path.

13. a flow path member having the first common flow path, the second common flow path, and the plurality of individual flow paths, and having a top surface on which the plurality of pressure chambers open; 13. The liquid ejection head according to claim 12, further comprising: an actuator member that is disposed on the upper surface so as to cover the openings of the plurality of pressure chambers, and that applies pressure to the liquid in each pressure chamber.

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