Liquid discharge head

Abstract

To achieve both high-density arrangement of a nozzle and suppression of enlargement in size in two directions thereof.SOLUTION: A head 1 includes a common passage 12 and a plurality of individual passages 13. An individual passage 13A includes communication passages 17A extending in a vertical direction D3. An individual passage 13B includes a communication passage 17B having a vertical passage 17B1 extending in the vertical direction. The plurality of communication passages 17A and the vertical passage 17B1 are arranged at one side of the common passage 12 in a second direction D2 and are lined in one row in a first direction D1. A plurality of nozzles 15 that communicate with the plurality of communication passages 17A lined in one row and the vertical passage 17B1 respectively are arranged in the first direction D1, below the common passage 12 to constitute a plurality of nozzle rows 15RA and 15RB arranged in the second direction D2. The nozzle row 15RB of the plurality of nozzle rows 15RA and 15RB overlaps with the common passage 12, in the vertical direction D3.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 describes a head that includes a common flow path and multiple individual flow paths that each include a nozzle, a pressurizing chamber (pressure chamber), and partial flow paths (communicating flow paths, upper and lower flow paths) that communicate between the nozzle and the pressurizing chamber, and that each communicate with the common flow path. In this head, the multiple nozzles form multiple nozzle rows that are arranged along the direction in which the common flow path extends. The multiple nozzle rows are arranged in pairs on either side of the common flow path in a direction perpendicular to the direction in which the common flow path extends. This allows the multiple nozzles to be arranged in a high density in the head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-138432 Summary of the Invention [Problem to be solved by the invention]

[0004] In the head described in Patent Document 1, partial flow paths (upper and lower flow paths) extending in the vertical direction are arranged above each nozzle. Therefore, there are two partial flow path rows arranged on one side of the common flow path, and the head becomes larger in the width direction (second direction) of the common flow path.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a liquid ejection head that can achieve both a high density arrangement of nozzles and suppression of an increase in size in the second direction. [Means for solving the problem]

[0006] The liquid ejection head of the present invention comprises a common flow path extending in a first direction perpendicular to the vertical direction, and a plurality of individual flow paths each including a nozzle, a pressure chamber, and a communicating flow path connecting the nozzle and the pressure chamber, the individual flow paths each communicating with the common flow path, wherein the pressure chamber is arranged above the nozzle and the common flow path, the plurality of communicating flow paths each including an upper and lower flow path extending in the vertical direction, the plurality of upper and lower flow paths being arranged on one side of the common flow path in a second direction perpendicular to the vertical direction and the first direction, and being aligned in a row in the first direction, the plurality of nozzles each communicating with the plurality of upper and lower flow paths aligned in the row are arranged in the first direction below the common flow path, and constitute a plurality of nozzle rows aligned in the second direction, and at least one of the plurality of nozzle rows overlaps the common flow path in the vertical direction. [Effects of the Invention]

[0007] According to the liquid ejection head of the present invention, a plurality of upper and lower flow paths arranged on one side (one side in the second direction) of a common flow path are aligned in a row in the first direction, and a plurality of nozzles communicating with the upper and lower flow paths form a plurality of nozzle rows. Moreover, at least one of the plurality of nozzle rows is arranged so as to effectively utilize the area below the common flow path (the area that overlaps with the common flow path in the vertical direction). This makes it possible to achieve both a high-density arrangement of nozzles and suppression of enlargement in the second direction. [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] FIG. 4 is a cross-sectional view of the head taken along line IV-IV in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view of the head taken along line VV in FIG. [Figure 6]FIG. 10 is a plan view of a main part of a flow path member of a head according to a second embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view of a main part of a flow path member of a head according to a third embodiment of the present invention. [Figure 8] FIG. 10 is a cross-sectional view of a main part of a flow path member of a head according to a fourth embodiment of the present invention. [Figure 9] FIG. 11 is a cross-sectional view of a main part of a flow path member of a head according to a fifth embodiment of the present invention. 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. 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 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] As shown in Fig. 3, two supply ports 111 and two return ports 112 open on the upper surface (surface) 21A of the flow path member 21. The two supply ports 111 are arranged at one end of the flow path member 21 in the first direction D1. The two return ports 112 are arranged at the other end of the flow path member 21 in the first direction D1. The supply ports 111 and the return ports 112 communicate with ink tanks via tubes. The flow path member 21 has two common flow paths 12, a plurality of individual flow paths 13, and two damper chambers 19.

[0019] The two common flow paths 12 are aligned in the second direction D2 and each extend in the 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] The two damper chambers 19 are disposed below the two common flow paths 12. The two damper chambers 19 are also aligned in the second direction D2 and extend in the first direction D1.

[0021] 3 to 5, 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.

[0022] 4, the flow path member 21 includes ten plates 121 to 130. The flow path member 21 may be configured with eleven or more or nine or fewer plates. Of the ten plates 121 to 130, the uppermost plate 121 has a plurality of pressure chambers 16 formed therein, and the lowermost plate 130 has a plurality of nozzles 15 formed therein. The plurality of pressure chambers 16 are located above the common flow path 12.

[0023] 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 129. 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. 4 and 5, the nozzles 15 have a shape that tapers downward.

[0024] Each common flow channel 12 is formed by connecting holes formed in two plates 124, 125. Each common flow channel 12 overlaps with all pressure chambers 16 communicating with the common flow channel 12 in the up-down direction D3.

[0025] Each damper chamber 19 is formed by blocking a hole formed in a plate 127 with two plates 126 and 128. The portion of the plate 126 sandwiched between the damper chamber 19 and the common flow path 12 functions as a damper 126A that 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 126A attenuates the pressure by elastically deforming, and can prevent the phenomenon of the pressure being transmitted to other pressure chambers 16 (so-called crosstalk).

[0026] 3, the individual flow paths 13 are arranged in a first direction D1 to form four individual flow path rows 14R. These individual flow path rows 14R are aligned in a second direction D2. Two rows of the four individual flow path rows 14R correspond to one common flow path 12.

[0027] Each individual flow path array 14R is configured such that individual flow paths 13A and individual flow paths 13B are alternately arranged in the first direction D1. Of the two individual flow path arrays 14R corresponding to each common flow path 12, the individual flow paths 13A included in one individual flow path array 14R (left in FIG. 3) and the individual flow paths 13A included in the other individual flow path array 14R (right in FIG. 3) have the same flow path configuration, including flow path shape and size. More specifically, the individual flow paths 13A included in one individual flow path array 14R and the individual flow paths 13A included in the other individual flow path array 14R are arranged point-symmetrically with respect to the midpoint of the line segment connecting the nozzles 15A in a plane perpendicular to the up-down direction D3.

[0028] Of the two individual flow path arrays 14R corresponding to each common flow path 12, the individual flow paths 13B included in one individual flow path array 14R and the individual flow paths 13B included in the other individual flow path array 14R have the same flow path configuration, including flow path shape and size. More specifically, the individual flow paths 13B included in one individual flow path array 14R and the individual flow paths 13B included in the other individual flow path array 14R are arranged point-symmetrically with respect to the midpoint of the line segment connecting the nozzles 15B in a plane perpendicular to the up-down direction D3.

[0029] The detailed configurations of the individual flow paths 13A and 13B will be described below.

[0030] As shown in FIG. 4, the individual flow path 13A includes a nozzle 15A, a pressure chamber 16A, a communication flow path 17A, and a connection flow path 18A.

[0031] The communication flow path 17A extends upward from the nozzle 15A along the vertical direction D3. The communication flow path 17A corresponds to the "upper and lower flow paths and second communication flow path" of the present invention. The communication flow path 17A is formed by interconnecting holes formed in each of the eight plates 122 to 129, and has a diameter larger than that of the nozzle 15A.

[0032] 3, the communicating flow paths 17A do not overlap with the common flow path 12 in the up-down direction D3, and are arranged on either one side (left side in FIG. 3) or the other side (right side in FIG. 3) of the common flow path 12 in the second direction D2. That is, of two individual flow path rows 14R corresponding to the same common flow path 12, the communicating flow paths 17A included in one individual flow path row 14R are arranged on one side of the common flow path 12, and the communicating flow paths 17A included in the other individual flow path row 14R are arranged on the other side of the common flow path 12. Of the multiple communicating flow paths 17A communicating with the same common flow path 12, the multiple communicating flow paths 17A arranged on one side of the common flow path 12 are arranged side by side in the first direction D1 in the second direction D2, and the multiple communicating flow paths 17A arranged on the other side of the common flow path 12 are arranged side by side in the first direction D1.

[0033] As shown in FIG. 4, the nozzles 15A are disposed directly below the communicating flow channels 17A and overlap with the communicating flow channels 17A in the vertical direction D3. That is, as shown in FIG. 3, the nozzles 15A do not overlap with the common flow channels 12 in the vertical direction D3, but are disposed on either one side or the other side of the common flow channels 12 in the second direction D2. Among the multiple nozzles 15A communicating with the same common flow channel 12, the multiple nozzles 15A disposed on one side of the common flow channel 12 and the multiple nozzles 15A disposed on the other side of the common flow channel 12 in the second direction D2 constitute two nozzle rows 15RA aligned in the first direction D1. The nozzles 15A overlap with the pressure chambers 16A in the vertical direction D3. The nozzles 15A correspond to the "second nozzles" of the present invention, and the nozzle row 15RA corresponds to the "second nozzle row" of the present invention.

[0034] As shown in FIG. 4, the connection flow path 18A is formed by connecting holes formed in the two plates 122 and 123 to each other, and is connected to the upper end of the common flow path 12.

[0035] As shown in FIG. 5, the individual flow path 13B includes a nozzle 15B, a pressure chamber 16B, a communication flow path 17B, and a connection flow path 18B.

[0036] The communicating flow path 17B includes an upper and lower flow path 17B1 and a horizontal flow path 17B2. The communicating flow path 17B corresponds to the "first communicating flow path" of the present invention. The upper and lower flow path 17B1 extends downward from the pressure chamber 16B along the vertical direction D3. As shown in FIG. 3, the upper and lower flow path 17B1 does not overlap with the common flow path 12 in the vertical direction D3, and is disposed on either one side (left side in FIG. 3) or the other side (right side in FIG. 3) of the common flow path 12 in the second direction D2. In other words, of the two individual flow path arrays 14R corresponding to the same common flow path 12, the upper and lower flow paths 17B1 included in one individual flow path array 14R are disposed on one side of the common flow path 12, and the upper and lower flow paths 17B1 included in the other individual flow path array 14R are disposed on the other side of the common flow path 12. Of the multiple upper and lower flow paths 17B1 connected to the same common flow path 12, in the second direction D2, the multiple upper and lower flow paths 17B1 arranged on one side of the common flow path 12 are arranged side by side in the first direction D1, and the multiple upper and lower flow paths 17B1 arranged on the other side of the common flow path 12 are arranged side by side in the first direction D1.

[0037] A plurality of communicating flow paths 17A and a plurality of upper and lower flow paths 17B1 that are connected to the same common flow path 12 and arranged on one side of the common flow path 12 are alternately arranged in a row along the first direction D1 to form a flow path array 17R. Also, a plurality of communicating flow paths 17A and a plurality of upper and lower flow paths 17B1 that are connected to the same common flow path 12 and arranged on the other side of the common flow path 12 are alternately arranged in a row along the first direction D1 to form a flow path array 17R.

[0038] 5, the vertical flow path 17B1 is formed by interconnecting holes formed in the seven plates 122 to 128, and has a diameter larger than that of the nozzle 15B. In this embodiment, the diameter of the holes that form the vertical flow path 17B1 is larger than the diameter of the holes that form the communication flow path 17A.

[0039] The horizontal flow path 17B2 extends from the nozzle 15B in the second direction D2 and communicates with the lower end of the vertical flow path 17B1. The horizontal flow path 17B2 is a hole formed in the plate 129. The flow path shapes and sizes of the communicating flow path 17A, the vertical flow path 17B1, and the horizontal flow path 17B2 are adjusted to each other so that the flow path resistances of the communicating flow path 17A and the communicating flow path 17B are the same. This makes it less likely that differences will occur in the ink ejection characteristics from the nozzle 15A and the nozzle 15B when ejecting ink. The second direction D2 corresponds to the "second direction and third direction" of the present invention, and the horizontal flow path 17B2 corresponds to the "portion extending in the third direction" of the present invention.

[0040] 5, the nozzles 15B are arranged so as to overlap with the common flow path 12 in the vertical direction D3. As shown in FIG. 3, the plurality of nozzles 15B communicating with the same common flow path 12 are arranged in the first direction D1 directly below the common flow path 12 to form two nozzle rows 15RB aligned in the second direction D2. The nozzles 15B also overlap with the pressure chambers 16B in the vertical direction D3. The nozzles 15B correspond to the "first nozzle" of the present invention, and the nozzle row 15RB corresponds to the "first nozzle row" of the present invention.

[0041] As shown in FIG. 5, the connection flow path 18B is formed by connecting holes formed in the two plates 122 and 123 to each other, and is connected to the upper end of the common flow path 12.

[0042] 3, in each individual flow path array 14R, the plurality of 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. Of the plurality of nozzles 15, two nozzles 15 adjacent to each other in the first direction D1 are arranged at a distance of ¼ of the pitch P in the first direction D1. As a result, when the printing resolution at the pitch P is 300 dpi, a printing resolution of 1200 dpi is achieved by all of the nozzles 15.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 3 to 5, the actuator member 22 is fixed to the upper surface 21A of the flow path member 21. As shown in FIGS. 4 and 5, the actuator member 22 includes a metallic vibration plate 31, a piezoelectric layer 32, and a plurality of individual electrodes 33.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] As described above, in the head 1 of this embodiment, the multiple individual flow paths 13A and the multiple individual flow paths 13B that communicate with the same common flow path 12 are arranged so that the multiple communicating flow paths 17A and the multiple upper and lower flow paths 17B1 form two flow path arrays 17R, and the multiple nozzles 15 form four nozzle arrays 15RA and 15RB. Of the two flow path arrays 17R, one flow path array 17R (left in FIG. 3) is arranged on one side outside the common flow path 12 in the second direction D2, and the other flow path array 17R (right in FIG. 3) is arranged on the other side outside the common flow path 12 in the second direction D2. The plurality of nozzles 15 included in the plurality of individual flow paths 13 that make up one or the other of the flow path rows 17R constitute two nozzle rows 15RA and 15RB, with the nozzle row 15RA located on one side or the other of the outer sides of the common flow path 12 in the second direction D2, and the nozzle row 15RB being positioned so as to overlap with the common flow path 12 in the up-down direction D3, thereby effectively utilizing the area below the common flow path 12. As a result, in the head 1, it is possible to achieve both a high-density arrangement of the nozzles 15 and suppression of enlargement in the second direction D2.

[0053] By arranging the nozzle row 15RB in a lower region overlapping with the common flow path 12 in the up-down direction D3, it is possible to make the distance in the second direction D2 between the nozzle row 15RA and the nozzle row 15RB adjacent to the nozzle row 15RA in the second direction D2 relatively large. As a result, when forming an image at the same position on the paper 9 in the second direction D2, the interval between the ink ejection timing from the nozzles 15 constituting the nozzle row 15RA and the ink ejection timing from the nozzles 15 constituting the nozzle row 15RB adjacent to the nozzle row 15RA in the second direction D2 also becomes large, making it easier to control the ejection timing.

[0054] The flow channel arrays 17R are arranged on both outer sides of the common flow channel 12 in the second direction D2, which allows the nozzles 15 to be arranged at a higher density.

[0055] Of the two nozzle rows 15RA and 15RB formed by the plurality of nozzles 15 included in the plurality of individual flow paths 13 that form one or the other of the flow path rows 17R, the nozzle row 15RA is arranged on one side or the other side in the second direction D2 of the common flow path 12. This allows the plurality of nozzles 15 to be arranged over a relatively wide range, including a range overlapping with the common flow path 12 in the up-down direction D3 and a range on one side or the other side of the common flow path 12 in the second direction D2.

[0056] All of the nozzles 15 included in the plurality of individual flow paths 13 that make up one or the other of the flow path rows 17R are arranged with a shift in the first direction D1, thereby improving the resolution in the first direction D1.

[0057] The communication flow path 17B that communicates with the nozzles 15B included in the nozzle row 15RB has an up-down flow path 17B1 and a horizontal flow path 17B2, which allows the nozzles 15B to be disposed below the common flow path 12 with a simple configuration.

[0058] The horizontal flow paths 17B2 extend parallel to the second direction D2. As a result, the plurality of nozzles 15A and the plurality of nozzles 15B are arranged in two staggered rows along the first direction D1, as shown in Fig. 3. In other words, the plurality of nozzles 15 are arranged regularly.

[0059] Furthermore, nozzle 15A, which is disposed outside common flow path 12 in second direction D2, is disposed directly below communicating flow path 17A and overlaps communicating flow path 17A in vertical direction D3. Because communicating flow path 17A extends in vertical direction D3, when ink is ejected from nozzle 15A, the pressure applied to the ink in pressure chamber 16A is easily transmitted to the ink in nozzle 15A. This makes it easy for ink to be ejected from nozzle 15A.

[0060] The flow path member 21 is configured by stacking a plurality of plates 121 to 130, and the individual flow paths 13 are configured by holes formed in the respective plates 121 to 130 communicating with each other. This simplifies the configuration of the plurality of individual flow paths 13.

[0061] Second Embodiment Next, a head according to a second embodiment of the present invention will be described with reference to Fig. 6. The head according to this embodiment is similar to the first embodiment except that the extension direction of the horizontal flow path 17B2 included in the individual flow path 13B is different from that of the first embodiment, and the nozzle 15B does not overlap with the pressure chamber 16B in the up-down direction D3. Note that components similar to those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0062] The horizontal flow path 17B2 extends from the lower end of the vertical flow path 17B1 in a third direction D4 that is perpendicular to the vertical direction D3 and intersects with the first direction D1 and the second direction D2, and communicates with the nozzle 15B.

[0063] By extending the horizontal flow paths 17B2 in the third direction D4 in this way, the nozzles 15B can be arranged with more freedom, making it easier to arrange a plurality of nozzles 15B.

[0064] Third Embodiment Next, a head according to a third embodiment of the present invention will be described with reference to Fig. 7. The head according to this embodiment has two nozzles 15B and 15C, each of which has an individual flow path 13B communicating with a horizontal flow path 17B2, and is otherwise the same as that of the first embodiment. Note that the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0065] Of the two nozzles 15B, 15C included in the individual flow path 13B, one nozzle 15C is arranged directly below the upper / lower flow path 17B1, and the other nozzle 15B is arranged to overlap with the common flow path 12 in the up-down direction D3. One nozzle 15C is arranged side by side with the nozzle 15A included in the individual flow path 13A in the first direction D1, and together with the nozzle 15A, constitutes a nozzle row 15RA. The other nozzle 15B constitutes the nozzle row 15RB described above. The nozzle row 15RA corresponds to the "second nozzle row" of the present invention, and the nozzle row 15RB corresponds to the "first nozzle row" of the present invention. Furthermore, the nozzle 15B corresponds to the "first nozzle" of the present invention, and the nozzle 15C corresponds to the "second nozzle" of the present invention.

[0066] In this way, one individual flow path 13B is connected to two nozzles 15B and 15C, and thus ink can be ejected from both nozzles 15B and 15C by applying pressure to the ink in pressure chamber 16B using actuator unit 35. In this case, high resolution is possible.

[0067] Alternatively, the shape and size of nozzle 15B and horizontal flow path 17B2 may be adjusted so that ink is ejected only from nozzle 15C when pressure is applied to the ink in pressure chamber 16B by actuator unit 35. In this way, when ink is ejected from one nozzle 15C of the two nozzles 15B and 15C and ink is not ejected from the other nozzle 15B, the ink pressure fluctuations caused by ink ejection from one nozzle 15C are absorbed by the ink meniscus of the other nozzle 15B. In other words, it is possible to attenuate pressure fluctuations when ink is ejected from nozzle 15C by utilizing the ink meniscus of the other nozzle 15B.

[0068] Furthermore, two nozzles 15B, 15C included in the plurality of individual flow paths 13B form a nozzle row 15RB that overlaps with the common flow path 12 in the up-down direction D3, and a nozzle row 15RA that is arranged on one side of the common flow path 12 in the second direction D2. This allows the plurality of nozzles 15 to be arranged over a relatively wide range.

[0069] Furthermore, nozzle 15C, which is disposed outside common flow path 12 in second direction D2, is disposed directly below up-down flow path 17B1 and overlaps with up-down flow path 17B1 in vertical direction D3. Because up-down flow path 17B1 extends in vertical direction D3, when ink is ejected from nozzle 15C, the pressure applied to the ink in pressure chamber 16B is easily transmitted to the ink in nozzle 15C. This makes it easy for ink to be ejected from nozzle 15C.

[0070] <Fourth embodiment> Next, a head according to a fourth embodiment of the present invention will be described with reference to Fig. 8. In the head according to this embodiment, the nozzle 15C communicating with the horizontal flow path 17B2 is positioned so as not to overlap with the vertical flow path 17B1 in the vertical direction D3, and the rest of the head is the same as in the third embodiment. Note that the same components as in the third embodiment are denoted by the same reference numerals and will not be described again.

[0071] Of the two nozzles 15B, 15C included in the individual flow path 13B, one nozzle 15C is disposed between the upper and lower flow paths 17B1 and the common flow path 12 in the second direction D2. This reduces the difference in flow path length from the pressure chamber 16B to the two nozzles 15B, 15C compared to the third embodiment. This makes it easier to adjust the flow path resistance from the pressure chamber 16B to each nozzle 15B, 15C, facilitating ink ejection from each nozzle 15B, 15C. Furthermore, when ink is ejected only from nozzle 15C of the two nozzles 15B, 15C, pressure fluctuations during ink ejection from nozzle 15C can be effectively attenuated by utilizing the ink meniscus of nozzle 15B.

[0072] Fifth Embodiment Next, a head according to a fifth embodiment of the present invention will be described with reference to Fig. 9. The head according to this embodiment has three nozzles 15B to 15D, each of which has an individual flow path 13B communicating with a horizontal flow path 17B2, and extends to a position where it overlaps in the vertical direction D3 with a common flow path 12 that is different from the common flow path 12 with which the horizontal flow path 17B2 communicates, and is otherwise the same as the fourth embodiment. Note that components similar to those in the fourth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0073] Two common flow paths 12 are formed in the flow path member 21. These two common flow paths 12 extend in a first direction D1 and are aligned in a second direction D2. The horizontal flow path 17B2 included in each individual flow path 13B extends in the second direction D2 so as to overlap with the two common flow paths 12 in the vertical direction D3, and connects the three nozzles 15B to 15D with the vertical flow paths 17B1.

[0074] The nozzles 15D included in each individual flow path 13B are arranged at positions overlapping in the up-down direction D3 with another common flow path 12 (the common flow path 12 on the left in FIG. 9) that is connected to the common flow path 12 (the common flow path 12 on the right in FIG. 9). The plurality of nozzles 15D arranged directly below the other common flow path 12 constitute a nozzle row (the "second nozzle row" of the present invention) arranged side by side in the first direction D1.

[0075] In this way, when there are multiple common flow paths 12, the multiple nozzles 15D can be arranged in a range overlapping with another common flow path 12 in the up-down direction D3 from the common flow path 12 that communicates with the multiple nozzles 15D. In other words, the multiple nozzles 15 can be arranged over a relatively wide range.

[0076] In the third to fifth embodiments described above, the individual flow paths 13A may have the same flow path shape as the individual flow paths 13B. This makes it possible to arrange the nozzles 15 at a higher density while suppressing an increase in the size of the head in the second direction D2.

[0077] 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.

[0078] In each of the above-described embodiments, a plurality of individual flow paths 13 constituting two individual flow path arrays 14R correspond to one common flow path 12, but a configuration in which a plurality of individual flow paths 13 constituting one individual flow path array 14R correspond to one common flow path 12 may also be used. Even in this configuration, the head is configured with one flow path array 17R and two nozzle arrays 15RA and 15RB, and at least one nozzle array 15RB overlaps the common flow path 12 in the up-down direction D3. This makes it possible to achieve both a high-density arrangement of nozzles 15 in the head and suppression of enlargement in the second direction D2, as in the above-described embodiments.

[0079] Furthermore, in each of the above-described embodiments, a plurality of individual flow paths 13 constituting two rows of individual flow path rows 14R correspond to one common flow path 12, but the pressure chambers 16 included in all of these individual flow paths 13 may be arranged in a row in the first direction D1, and each communicating flow path 17 may be arranged in a row on one side of the common flow path 12 outside in the second direction D2.

[0080] In each embodiment, the up-down direction D3 may be a direction intersecting the vertical direction and the horizontal direction, in which case the communication flow path 17A and the up-down flow path 17B1 may extend in the intersecting direction.

[0081] In the first to fourth embodiments described above, all the nozzles 15 constituting each nozzle row may be arranged at positions overlapping the corresponding common flow paths 12 in the up-down direction D3.

[0082] In the first embodiment described above, the flow path resistances of the communication flow path 17A and the communication flow path 17B are the same, but they may be different from each other. Also, the hole diameter of the communication flow path 17A and the hole diameter of the up-down flow path 17B1 may be the same.

[0083] 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.

[0084] The type of liquid ejection head of the present invention is not limited to the line type, but may also be a serial type.

[0085] The object onto which the droplets are ejected is not limited to paper, but may be, for example, a cloth, a substrate, or plastic.

[0086] 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.

[0087] 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]

[0088] 1 head (liquid ejection head) 12 Common flow path 13 Individual flow path 15 nozzles 15A Nozzle (2nd Nozzle) 15B Nozzle (1st Nozzle) 15RA nozzle row (second nozzle row) 15RB nozzle row (first nozzle row) 16 Pressure Chamber 17 Connecting flow path 17A Communication channel (upstream / downstream channel) 17B1 Upstream and downstream channels 17R flow channel row D1 1st direction D2 2nd direction D3 Up and down direction D4 3rd direction

Claims

1. a common flow path extending in a first direction perpendicular to the up-down direction; a plurality of individual flow paths each including a nozzle, a pressure chamber, and a communication flow path that communicates the nozzle with the pressure chamber, the individual flow paths each communicating with the common flow path; the pressure chamber is disposed above the nozzle and the common flow path, each of the plurality of communication channels includes an up-down channel extending in a vertical direction; the plurality of upper and lower flow paths are arranged on one side of the common flow path in the vertical direction and in a second direction perpendicular to the first direction, and are aligned in a row in the first direction; the plurality of nozzles respectively communicating with the plurality of upper and lower flow paths arranged in one row are arranged in the first direction below the common flow path and constitute a plurality of nozzle rows arranged in the second direction; A liquid ejection head, wherein at least one of the plurality of nozzle rows overlaps the common flow path in the vertical direction.

2. 2. The liquid ejection head according to claim 1, wherein at least one other nozzle row among the plurality of nozzle rows is disposed outside one side of the common flow path in the second direction.

3. 2. A liquid ejection head according to claim 1, wherein a first communication flow path communicating with a first nozzle included in a first nozzle row among the plurality of nozzle rows and a second communication flow path communicating with a second nozzle included in a second nozzle row different from the first nozzle row among the plurality of nozzle rows have the same flow path resistance.

4. 2. The liquid ejection head according to claim 1, wherein all of the nozzles included in the plurality of nozzle rows are arranged so as to be shifted in the first direction.

5. The liquid ejection head according to claim 4, characterized in that the communicating flow path that communicates with the nozzles included in the nozzle row that overlaps the common flow path in the vertical direction has a portion that extends from the lower end of the vertical flow path in a third direction perpendicular to the vertical direction.

6. 6. The liquid ejection head according to claim 5, wherein the third direction is the second direction.

7. 6. The liquid ejection head according to claim 5, wherein the third direction is a direction intersecting the first direction and the second direction.

8. 2. A liquid ejection head according to claim 1, wherein the communication flow path is connected to a first nozzle included in a first nozzle row among the plurality of nozzle rows, and a second nozzle included in a second nozzle row different from the first nozzle row among the plurality of nozzle rows.

9. further comprising another common flow path extending in the first direction and aligned with the common flow path in the second direction; the first nozzle row overlaps with the common flow path in the vertical direction, 9. The liquid ejection head according to claim 8, wherein the second nozzle row overlaps with the other common flow path in the vertical direction.

10. the first nozzle row overlaps with the common flow path in the vertical direction, 9. The liquid ejection head according to claim 8, wherein the second nozzle row is arranged outside one of the common flow paths in the second direction.

11. 11. The liquid ejection head according to claim 2, wherein the nozzles included in one of the nozzle rows arranged on one outer side of the common flow path overlap with the upper and lower flow paths in the vertical direction.

12. a plurality of plates stacked on top of each other, each plate having a plurality of holes; 2. The liquid ejection head according to claim 1, wherein the individual flow paths are formed by the holes of the plurality of plates communicating with each other.

13. 2. The liquid ejection head according to claim 1, wherein the upper and lower flow paths are also disposed on the other side of the common flow path in the second direction.

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