Head chip, liquid jet head, liquid jet recording apparatus, and method of manufacturing head chip

Abstract

To provide a head chip, a liquid jet head, a liquid jet recording apparatus, and a method of manufacturing a head chip each capable of preventing an occurrence of an unwanted processing residual due to laser processing.SOLUTION: The head chip according to an aspect of the present disclosure includes a flow channel member which includes a recess formed of a first laser irradiation trace, and in which a liquid circulates in the recess, and a bonded member which is bonded to the flow channel member so as to close the recess. The flow channel member is provided with a second laser irradiation trace which is formed while extending along an opening edge of the recess.SELECTED DRAWING: Figure 28

Description

[Technical Field]

[0001] The present disclosure relates to a head chip, a liquid jet head, a liquid jet recording apparatus, and a method for manufacturing the head chip. [Background technology]

[0002] A head chip mounted on an inkjet printer may include a flow path member in which a recess is formed for ink flow, and a joining member joined to the flow path member so as to close the recess. The recess is formed, for example, by laser processing (see, for example, Patent Document 1 listed below). In laser processing, a laser beam is scanned over the surface of the flow path member in the area where the recess is to be formed. As a result, a recess is formed in the scanned area of ​​the laser beam due to the laser irradiation marks. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-297180 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when forming recesses by laser processing, portions of the flow path member that are melted by laser irradiation may scatter and adhere as foreign matter (hereinafter referred to as "burrs") near the opening edge of the recess. If unnecessary processing residues such as burrs protrude beyond the surface of the flow path member, they may become trapped between the flow path member and the joining member when the joining member is joined to the surface of the flow path member. If unnecessary processing residues become trapped, it may lead to ink leakage between the flow path member and the joining member, peeling of the joining member, etc.

[0005] The present disclosure provides a head chip, a liquid jet head, a liquid jet recording apparatus, and a method for manufacturing a head chip, which are capable of suppressing the generation of unnecessary processing residues that occur during laser processing. [Means for solving the problem]

[0006] In order to solve the above problems, the present disclosure employs the following aspects. (1) A head chip according to one aspect of the present disclosure includes a recess formed by a first laser irradiation mark, a flow path member through which a liquid flows within the recess, and a joining member joined to the flow path member so as to close the recess, and a second laser irradiation mark extending along the opening edge of the recess is formed on the flow path member.

[0007] According to this aspect, the formation of the second laser irradiation marks along the opening edge of the recess reduces unnecessary processing residues remaining on the opening edge of the recess after the formation of the first laser irradiation marks. This prevents the unnecessary processing residues from getting caught when joining the flow path member and the joining member. As a result, liquid leakage between the flow path member and the joining member is suppressed, and the joining strength between the flow path member and the joining member is ensured. Furthermore, by reducing the unnecessary processing residues within the recess, unevenness within the recess can be suppressed. This reduces the flow resistance of the liquid flowing within the recess, allowing the liquid to flow smoothly within the recess.

[0008] (2) In the head chip according to the aspect (1) above, the recess has a non-penetrating portion that opens only on the surface of the flow path member that faces the joining member in the thickness direction, and a penetrating portion that opens on the bottom surface of the non-penetrating portion and penetrates the flow path member in the thickness direction, and it is preferable that the second laser irradiation mark extends at least along the opening edge of the non-penetrating portion. According to this aspect, unnecessary processing residue remaining on the opening edge of the non-penetrating portion may be exposed on the joining surface of the flow path member with the joining member. Therefore, by forming the second laser irradiation mark at least along the opening edge of the non-penetrating portion, it is possible to prevent the unnecessary processing residue from being exposed on the joining surface of the flow path member with the joining member.

[0009] (3) In the head chip according to the above aspect (1) or (2), it is preferable that the first laser irradiation marks extend in a first direction intersecting the thickness direction of the flow path member and are formed in multiple rows in a second direction intersecting the first direction when viewed from the thickness direction, and the second laser irradiation marks extend in the first direction along an outer laser irradiation mark that is located outermost in the second direction among the multiple first laser irradiation marks. According to this aspect, by forming the second laser irradiation mark along the outer laser irradiation mark among the multiple first laser irradiation marks, unnecessary processing residue remaining along the extension direction of the outer laser irradiation mark can be effectively reduced.

[0010] (4) In the head chip according to the above aspect (3), it is preferable that the center of the second laser irradiation mark in the second direction is located more inward in the second direction than the center of the outer laser irradiation mark in the second direction. According to this aspect, by positioning the center of the second laser irradiation mark in the second direction more inward than the center of the outer laser irradiation mark in the second direction, unwanted processing residues such as burrs can be removed by the influence of heat propagating around the laser light used to form the second laser irradiation mark. In this case, the influence of heat propagating to the opening edge of the recess can be reduced compared to when the laser light used to form the second laser irradiation mark is scanned along the same trajectory as the laser light used to form the outer laser irradiation mark. This prevents unwanted processing residues such as twists formed on the outer periphery of the recess from being amplified by the laser light used to form the second laser irradiation mark. Therefore, when joining the flow path member and the joining member, it is possible to prevent unwanted processing residues such as twists from being trapped. As a result, liquid leakage between the flow path member and the joining member can be suppressed, and the joining strength between the flow path member and the joining member can be ensured.

[0011] (5) In the head chip according to any one of the above aspects (1) to (4), it is preferable that the recess is formed in a rectangular shape with the first direction as the longitudinal direction and the second direction as the short direction when viewed from the thickness direction. According to this aspect, the longitudinal direction of the recess and the extending direction of the second laser irradiation mark coincide with each other, so that unnecessary processing residues can be reduced along the longitudinal direction of the recess.

[0012] (6) In a head chip according to any one of the above aspects (1) to (5), the recess comprises a non-penetrating portion that opens only on the surface of the flow path member that faces the joining member in the thickness direction, and a penetrating portion that opens on the bottom surface of the non-penetrating portion and penetrates the flow path member in the thickness direction, the penetrating portion including a first penetrating portion and a second penetrating portion that is spaced apart from the first penetrating portion in the first direction and communicates with the first penetrating portion through the non-penetrating portion, and a chip body is joined on the opposite side of the flow path member from the joining member in the thickness direction, the chip body having a pressure chamber that communicates with the inside of the recess through the first penetrating portion and a circulation path that communicates with the inside of the recess through the second penetrating portion, and the joining member is preferably formed with an injection hole that injects liquid from the recess to the outside. According to this aspect, the flow path member communicates with the ejection hole and functions as a return plate that circulates the liquid through the ejection channel and the circulation path. In this case, in the head chip according to the present disclosure, since unevenness within the recess can be suppressed, the liquid can be smoothly circulated between the ejection hole, the ejection channel, and the circulation path through the recess.

[0013] (7) A liquid jet head according to an aspect of the present disclosure preferably includes the head chip according to any one of the above aspects (1) to (6). According to this aspect, it is possible to provide a liquid jet head with excellent reliability.

[0014] (8) A liquid jet recording apparatus according to one aspect of the present disclosure includes the liquid jet head according to the above aspect (7). According to this aspect, it is possible to provide a highly reliable liquid jet recording apparatus.

[0015] (9) A method for manufacturing a head chip according to one aspect of the present disclosure is a method for manufacturing a head chip including a flow path member having a recess formed therein through which a liquid flows, and a joining member joined to the flow path member so as to close the recess, and includes a first laser irradiation process for irradiating a joining surface of the flow path member with the joining member with a first laser light to form an outline of the recess with a first laser irradiation mark, and a second laser irradiation process for irradiating a second laser light along the opening edge of the recess to form a second laser irradiation mark along the opening edge of the recess. [Effects of the Invention]

[0016] According to one aspect of the present disclosure, it is possible to suppress the occurrence of unnecessary processing residues that occur during laser processing. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram of a printer according to a first embodiment. [Figure 2] FIG. 2 is a schematic configuration diagram of an inkjet head and an ink circulation mechanism according to the first embodiment. [Figure 3] FIG. 2 is an exploded perspective view of the head chip according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view corresponding to the line VI-VI in FIG. [Figure 7] FIG. 7 is an enlarged view of part VII in FIG. [Figure 8] FIG. 8 is a cross-sectional view corresponding to line VIII-VIII in FIG. [Figure 9] 4 is a flowchart for explaining a method for manufacturing a head chip according to the first embodiment. [Figure 10] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 11] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 12] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 13] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 14] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 15] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 16] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 17] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 18] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 19] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 20] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 21] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 22] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 23] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 24] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 25] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 26] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 27] 3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 28]3A to 3C are process diagrams illustrating a method for manufacturing a head chip according to the first embodiment. [Figure 29] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a second embodiment. [Figure 30] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a second embodiment. [Figure 31] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a second embodiment. [Figure 32] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a second embodiment. [Figure 33] 10 is a flowchart illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 34] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 35] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 36] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 37] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 38] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 39] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 40] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 41] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 42] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 43] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 44]10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 45] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 46] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 47] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 48] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 49] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 50] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a third embodiment. [Figure 51] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a fourth embodiment. [Figure 52] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a fourth embodiment. [Figure 53] 10A to 10C are process diagrams illustrating a method for manufacturing a head chip according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the embodiments and modified examples described below, corresponding components may be designated by the same reference numerals and their description may be omitted. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," not only strictly refer to such arrangements, but also refer to a state in which there is a relative displacement with a tolerance or an angle or distance that provides the same function. In the following embodiments, an inkjet printer (hereinafter simply referred to as a printer) that records on a recording medium using ink (liquid) will be described as an example. In the drawings used in the following description, the scale of each component has been appropriately changed to make each component recognizable.

[0019] (First embodiment) [Printer 1] FIG. 1 is a schematic diagram of the printer 1. As shown in FIG. 1, the printer (liquid jet recording apparatus) 1 of the first embodiment includes a pair of transport mechanisms 2 and 3, an ink tank 4, an inkjet head (liquid jet head) 5, an ink circulation mechanism 6, and a scanning mechanism 7.

[0020] In the following explanation, an X, Y, Z Cartesian coordinate system will be used as necessary. In this case, the X direction corresponds to the transport direction (sub-scanning direction) of the recording medium P (e.g., paper, etc.). The Y direction corresponds to the scanning direction (main scanning direction) of the scanning mechanism 7. The Z direction indicates the height direction (gravity direction) perpendicular to the X and Y directions. In the following explanation, of the X, Y, and Z directions, the arrow side in the figure is the plus (+) side, and the opposite side to the arrow is the minus (-) side. In the first embodiment, the +Z side corresponds to the upward direction in the direction of gravity, and the -Z side corresponds to the downward direction in the direction of gravity.

[0021] The transport mechanisms 2 and 3 transport the recording medium P to the +X side. The transport mechanisms 2 and 3 each include a pair of rollers 11 and 12 extending in the Y direction, for example. The ink tanks 4 each contain four colors of ink, for example, yellow, magenta, cyan, and black. Each inkjet head 5 is configured to be able to eject the four colors of ink, yellow, magenta, cyan, and black, respectively, according to the ink tank 4 connected to it.

[0022] FIG. 2 is a schematic diagram of the inkjet head 5 and the ink circulation mechanism 6. As shown in FIG. 1 and 2, the ink circulation mechanism 6 circulates ink between the ink tank 4 and the inkjet head 5. Specifically, the ink circulation mechanism 6 includes a circulation flow path 23 having an ink supply pipe 21 and an ink discharge pipe 22, a pressure pump 24 connected to the ink supply pipe 21, and a suction pump 25 connected to the ink discharge pipe 22.

[0023] The pressure pump 24 pressurizes the ink supply pipe 21 and sends ink to the inkjet head 5 through the ink supply pipe 21. As a result, the ink supply pipe 21 side relative to the inkjet head 5 becomes a positive pressure. The suction pump 25 reduces the pressure inside the ink discharge pipe 22 and sucks ink from the inkjet head 5 through the ink discharge pipe 22. This creates a negative pressure on the ink discharge pipe 22 side relative to the inkjet head 5. By driving the pressure pump 24 and the suction pump 25, the ink can be circulated between the inkjet head 5 and the ink tank 4 through the circulation flow path 23.

[0024] The scanning mechanism 7 moves the inkjet head 5 back and forth in the Y direction. The scanning mechanism 7 includes a guide rail 28 extending in the Y direction, and a carriage 29 movably supported on the guide rail 28.

[0025] <Inkjet head 5> As shown in Fig. 1, the inkjet head 5 is mounted on a carriage 29. In the illustrated example, a plurality of inkjet heads 5 are mounted side by side in the Y direction on one carriage 29. The inkjet head 5 includes a head chip 50 (see Fig. 3), an ink supply unit (not shown) that connects the ink circulation mechanism 6 and the head chip 50, and a control unit (not shown) that applies a drive voltage to the head chip 50.

[0026] <Head chip 50> Fig. 3 is an exploded perspective view of the head chip 50. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 3. Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. As shown in Figures 3 to 5, the head chip 50 is a so-called edge shoot type that ejects ink from the tip of the ejection channel 71 (described later) in the channel extension direction (Z direction), and is a circulation type (vertical circulation type) that circulates ink between the ink tank 4.

[0027] The head chip 50 includes a first chip module 51A, a second chip module 51B, a feedback plate 52, and a nozzle plate 53. In the following explanation, the configuration of each chip module 51A, 51B will be explained using the first chip module 51A as an example. Therefore, in the second chip module 51B, the same configuration as the first chip module 51A will be assigned the same reference numerals as the first chip module 51A, and explanations thereof may be omitted.

[0028] <First chip module 51A> The first chip module 51A includes a first actuator plate 61, a first cover plate 62, and a first back plate 63. In the following description, the +Y side of the first chip module 51A will be referred to as the front side, and the -Y side as the back side.

[0029] The first actuator plate 61 is a laminated substrate (a so-called chevron type) in which two piezoelectric substrates are stacked together, with the polarization directions being different in the thickness direction (Y direction). Note that a ceramic substrate made of PZT (lead zirconate titanate) or the like is preferably used as the piezoelectric substrate. However, the first actuator plate 61 may also be formed from a single piezoelectric substrate with the polarization direction set in one direction (a so-called monopole type).

[0030] The first actuator plate 61 is formed with ejection channels 71 that are filled with ink and non-ejection channels 72 that are not filled with ink. The channels 71, 72 are alternately arranged at intervals in the X direction on the first actuator plate 61 to form a channel row 70. In the first embodiment, a configuration will be described in which the channel extension direction coincides with the Z direction (extension direction), but the channel extension direction may also intersect with the Z direction.

[0031] 3 and 4, the upper end of the discharge channel 71 terminates inside the first actuator plate 61, and the lower end opens at the lower end surface of the first actuator plate 61. Meanwhile, the upper part of the discharge channel 71 has a depth in the Y direction that gradually decreases toward the top. The lower part of the discharge channel 71 penetrates the first actuator plate 61 in the Y direction. 3 and 5, the non-ejection channels 72 penetrate the first actuator plate 61 in the Z direction. The non-ejection channels 72 penetrate the first actuator plate 61 in the Y direction over the entire length in the Z direction. That is, the depth of the non-ejection channels 72 in the Y direction is uniform over the entire length in the Z direction.

[0032] The portions of the first actuator plate 61 located between the discharge channel 71 and the non-discharge channel 72 each constitute a drive wall 75. Therefore, the discharge channel 71 is surrounded on both sides in the X direction by a pair of drive walls 75. The portion of the first actuator plate 61 located above the discharge channel 71 constitutes a tail portion 76.

[0033] <First cover plate 62> 3 to 5, the first cover plate 62 is joined to the surface of the first actuator plate 61. Specifically, the first cover plate 62 closes the front-side openings of the channels 71, 72 while leaving the surface of the tail portion 76 exposed. The lower end surface of the first cover plate 62 is disposed flush with the lower end surface of the first actuator plate 61.

[0034] A common ink chamber 80 is formed in the first cover plate 62 at a position overlapping the top of the ejection channel 71 when viewed from the Y direction. The common ink chamber 80 extends in the X direction, for example, to a length spanning the channel row 70, and opens on the surface of the first cover plate 62. The common ink chamber 80 is indirectly connected to the ink supply pipe 21 through an inlet port (not shown). In the common ink chamber 80, slits 81 are formed separately at positions that overlap the upper portions of the ejection channels 71 when viewed from the Y direction. The slits 81 communicate between the inside of the ejection channels 71 and the inside of the common ink chamber 80 through the upper portions of the ejection channels 71. Therefore, the common ink chamber 80 communicates with each of the ejection channels 71 through each slit 81, but does not communicate with each of the non-ejection channels 72.

[0035] <First Back Plate 63> The first back plate 63 is joined to the back surface of the first actuator plate 61. The first back plate 63 has the same external shape as the first actuator plate 61 when viewed from the Y direction. The first back plate 63 is superimposed on the entire first actuator plate 61 when viewed from the Y direction. In other words, the first back plate 63 closes the back surface openings of each of the channels 71, 72.

[0036] As shown in FIG. 3, the first actuator plate 61 is provided with common wiring 85 and individual wiring 86 as drive wiring. As shown in FIGS. 3 and 4, the common wiring 85 includes a common electrode 87 and a common terminal 88. The common electrodes 87 are formed on inner surfaces of the ejection channel 71 that face each other in the X direction. In the illustrated example, the common electrode 87 is formed on the entire inner surface of the ejection channel 71 in the Y and Z directions. It is sufficient that the common electrode 87 is formed on a portion of the inner surface of the ejection channel 71 that is located at least below the lower opening edge of the slit 81.

[0037] The common terminals 88 are formed on the surface of the tail portion 76. The common terminals 88 are provided on the surface of the tail portion 76 corresponding to each discharge channel 71. Each common terminal 88 extends linearly in the Z direction above the corresponding discharge channel 71. The lower end of the common terminal 88 is connected to the common electrode 87 at the upper opening edge of the discharge channel 71.

[0038] As shown in FIGS. 3 and 5, the individual wiring 86 includes an individual electrode 91 and an individual terminal 92. The individual electrodes 91 are formed on inner surfaces of the non-ejection channels 72 that face each other in the X direction. In the illustrated example, the individual electrodes 91 are formed over the entire area in the Y and Z directions on the inner surfaces of the non-ejection channels 72. Note that it is sufficient that the individual electrodes 91 are formed in positions facing the common electrode 87, at least in portions that are located below the lower opening edge of the slit 81.

[0039] The individual terminals 92 are formed on the surface of the tail portion 76 in a portion located above the common terminal 88. The individual terminals 92 are formed in a strip shape extending in the X direction. The individual terminals 92 connect the common electrodes 87 that face each other in the X direction, with the ejection channel 71 sandwiched between them, at the opening edges on the surface sides of the non-ejection channels 72 that face each other in the X direction, with the ejection channel 71 sandwiched between them. A separating groove 79 is formed in the tail portion 76 in a portion located between the common terminal 88 and the individual terminal 92. The separating groove 79 opens on the surface of the tail portion 76 and extends in the X direction. The separating groove 79 separates the common terminal 88 from the individual terminal 92. The depth of the separating groove 79 in the Y direction is less than half the thickness of the first actuator plate 61. However, the depth of the separating groove 79 can be changed as appropriate as long as it does not cut the individual electrodes 91.

[0040] A flexible printed circuit board (not shown) is crimped onto the surface of the tail portion 76. The flexible printed circuit board is connected to the common terminal 88 and the individual terminals 92 on the surface of the tail portion 76. The flexible printed circuit board connects the first chip module 51A and the control unit.

[0041] <Second chip module 51B> The second chip module 51B includes a second actuator plate 101, a second cover plate 102, and a second back plate 103. In the second chip module 51B, the second back plate 103, the second actuator plate 101, and the second cover plate 102 are stacked in order from the +Y side to the -Y side. The second chip module 51B is stacked on the first chip module 51A with the front surface side (-Y side) facing away from the first chip module 51A. Specifically, the first chip module 51A and the second chip module 51B are integrated by joining the back surfaces of the first back plate 63 and the second back plate 103. In this case, the lower end surfaces of the chip modules 51A and 51B are arranged flush with each other.

[0042] The ejection channels 71 and non-ejection channels 72 of the second tip module 51B are arranged at a half-pitch offset from the arrangement pitch of the ejection channels 71 and non-ejection channels 72 of the first tip module 51A. That is, the ejection channels 71 and non-ejection channels 72 of each tip module 51A, 51B are arranged in a staggered pattern. In this case, the ejection channels 71 of the first tip module 51A and the non-ejection channels 72 of the second tip module 51B face each other in the Y direction, and the non-ejection channels 72 of the first tip module 51A and the ejection channels 71 of the second tip module 51B face each other in the Y direction. Note that the pitch of the channels 71, 72 of each tip module 51A, 51B can be changed as appropriate.

[0043] <Return Plate 52> The feedback plate 52 is bonded to the lower end surfaces of the chip modules 51A, 51B together via an adhesive. The feedback plate 52 closes the lower end openings of the channels 71, 72. The feedback plate 52 is made of, for example, polyimide. The feedback plate 52 has a plurality of first communication paths 110 and a plurality of second communication paths 111 formed therein. Note that the first communication paths 110 and the second communication paths 111 are formed by a plurality of rows of laser irradiation marks, as will be explained in the manufacturing method described below. However, in FIGS. 4 to 7, the inner surfaces of the first communication paths 110 and the second communication paths 111 are shown as smooth surfaces for convenience.

[0044] Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 4. Fig. 7 is an enlarged view of part VII in Fig. 4. As shown in FIGS. 6 and 7 , the multiple first communication passages 110 are individually formed in the first tip module 51A at positions equivalent in the X direction to the respective discharge channels 71. In the first embodiment, the multiple first communication passages 110 are formed at intervals in the X direction corresponding to the arrangement pitch of the discharge channels 71. Each first communication passage 110 is a recess formed in a U-shape when viewed from the side in the X direction. Specifically, each first communication passage 110 has an upstream opening (through portion) 115, a downstream opening (through portion) 116, and a connection portion (non-through portion) 117. Since all the first communication passages 110 have the same configuration, the following configuration will be described in detail using one first communication passage 110 as an example.

[0045] The upstream opening 115 is formed at a position overlapping the discharge channel 71 when viewed from the Z direction. The upstream opening 115 has an upper end opening at the upper surface of the return plate 52 and a lower end terminating inside the return plate 52. The upstream opening 115 communicates with the inside of the discharge channel 71 through the lower end opening of the discharge channel 71.

[0046] At least a part of the opening edge of the upstream opening 115 is positioned outward from the lower end opening edge of the discharge channel 71 when viewed in the Z direction. Specifically, the dimension of the upstream opening 115 in the X direction is smaller than the dimension of the lower end opening of the discharge channel 71 in the X direction. The dimension of the upstream opening 115 in the Y direction is larger than the dimension of the lower end opening of the discharge channel 71 in the Y direction. Portions of the lower end surface of the first tip module 51A located on both sides of the discharge channel 71 in the Y direction are exposed through the upstream opening 115.

[0047] The downstream opening 116 is formed at a position overlapping with the first back plate 63 when viewed from the Z direction. The upper end of the downstream opening 116 opens at the upper surface of the feedback plate 52, and the lower end terminates inside the feedback plate 52. The dimension of the downstream opening 116 in the Z direction is the same as that of the upstream opening 115.

[0048] The connection portion 117 is open only on the lower surface of the feedback plate 52, and connects the upstream opening 115 and the downstream opening 116 to each other. When viewed from the Z direction, the connection portion 117 is formed in a rectangular shape with its short side in the X direction and its long side in the Y direction. In the first embodiment, the dimension of the connection portion 117 in the Z direction is larger than the dimensions of the upstream opening 115 and the downstream opening 116 in the Z direction. However, the dimension of the connection portion 117 in the Z direction may differ depending on the position in the Y direction.

[0049] When viewed from the Z direction, the dimension of the connecting portion 117 in the X direction is larger than those of the upstream opening 115 and the downstream opening 116. Specifically, the connecting portion 117 includes an upstream wide portion 117a and a downstream wide portion 117b. The upstream wide portion 117a is disposed at a position overlapping the upstream opening 115 when viewed from the Z direction. The upstream wide portion 117a is slightly larger than the upstream opening 115 when viewed from the Z direction. The upstream opening 115 opens on the downward-facing surface (bottom surface) of the inner surface of the upstream wide portion 117a. Therefore, the upstream opening 115 penetrates the feedback plate 52 in the Z direction via the upstream wide portion 117a.

[0050] The downstream wide portion 117b extends from the upstream wide portion 117a to the -Y side. The downstream wide portion 117b overlaps with the downstream opening 116 when viewed in the Z direction. The downstream wide portion 117b is slightly larger than the downstream opening 116 when viewed in the Z direction. The dimension of the downstream wide portion 117b in the X direction is smaller than that of the upstream wide portion 117a. The downstream opening 116 opens on the bottom surface of the downstream wide portion 117b. Therefore, the downstream opening 116 penetrates the feedback plate 52 in the Z direction via the downstream wide portion 117b.

[0051] 5, the second communication passages 111 are formed separately at positions in the X direction equivalent to the positions of the discharge channels 71 in the second tip module 51B. In the first embodiment, the second communication passages 111 are formed at intervals in the X direction corresponding to the arrangement pitch of the discharge channels 71 in the second tip module 51B. That is, the first communication passages 110 and the second communication passages 111 are alternately arranged at intervals in the X direction. The second communication passages 111 have the same configuration as the first communication passages 110. Therefore, the same components of the second communication passages 111 as those of the first communication passages 110 are denoted by the same reference numerals, and detailed description of the second communication passages 111 will be omitted.

[0052] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 4 and 8, the first back plate 63 and the second back plate 103 are stacked on top of each other to form a flow path plate 120. The flow path plate 120 has a plurality of first connection paths 121, a plurality of second connection paths 122, and a manifold 123 formed therein.

[0053] The multiple first connection paths 121 are individually formed at positions overlapping with the downstream openings 116 of the respective first communication paths 110 when viewed from the Z direction. The first connection paths 121 are arranged at intervals in the X direction at the same pitch as the first communication paths 110. Specifically, the first connection paths 121 open on the back surface of the first back plate 63. The back surface opening of the first connection paths 121 is closed by the second back plate 103.

[0054] The first connection path 121 extends linearly in the Z direction when viewed from the Y direction. The lower end of the first connection path 121 opens on the lower end surface of the first back plate 63. As a result, the lower end opening of the first connection path 121 communicates with the downstream opening 116. On the other hand, the upper end of the first connection path 121 terminates inside the first back plate 63.

[0055] 6, the dimension in the X direction of the lower end opening of the first connecting path 121 is larger than that of the downstream opening 116 and smaller than that of the downstream wide portion 117b. In this case, the opening edge of the downstream opening 116 protrudes inward relative to the lower end opening edge of the first connecting path 121. However, the dimension in the X direction of the lower end opening of the first connecting path 121 may be larger than that of the downstream wide portion 117b or smaller than that of the downstream opening 116.

[0056] 8, the second connection paths 122 are individually formed at positions overlapping the downstream openings 116 of the second communication paths 111 when viewed from the Z direction. The second connection paths 122 are arranged at intervals in the X direction at the same pitch as the second communication paths 111. That is, the first connection paths 121 and the second connection paths 122 are arranged alternately in the X direction.

[0057] As shown in FIGS. 5 and 6 , each second connection path 122 communicates with the downstream opening 116 of the corresponding second communication path 111. Specifically, the second connection path 122 opens on the back surface (surface facing the +Y side) of the second back plate 103. The back surface opening of the second connection path 122 is closed by the first back plate 63. The second connection path 122 extends in the Z direction. The lower end of the second connection path 122 opens on the lower end surface of the second back plate 103. As a result, the lower end opening of the second connection path 122 communicates with the downstream opening 116 of the second communication path 111. Meanwhile, the upper end of the second connection path 122 terminates inside the second back plate 103. The dimensions of the second connection path 122 can be set similarly to those of the first connection path 121.

[0058] The manifold 123 is formed in a portion of the flow path plate 120 located above the connection paths 121 and 122. The manifold 123 is formed by overlapping a first recess 123a formed in the first back plate 63 and a second recess 123b formed in the second back plate 103. The first recess 123a is a recess that opens on the back surface of the first back plate 63 and extends in the Z and Y directions. The second recess 123b is a recess that opens on the back surface of the second back plate 103 and extends in the Z and Y directions. The manifold 123 is formed by connecting the back surface side openings of the first recess 123a and the second recess 123b to each other. Note that the manifold 123 may be configured such that a recess formed in only one of the first back plate 63 and the second back plate 103 is closed by the back surface of the other back plate.

[0059] The connection paths 121, 122 are all connected to the manifold 123. Specifically, the upper end opening of each first connection path 121 is open on the lower end surface of the first recess 123a. The upper end opening of each second connection path 122 is open on the lower end surface of the second recess 123b. The manifold 123 is indirectly connected to the ink discharge tube 22 through an outlet port (not shown).

[0060] The chip modules 51A, 51B and the feedback plate 52 are covered with a protective film 125. In the first embodiment, the protective film 125 is also formed on the inner surface of the common ink chamber 80, the inner surface of the slit 81, the inner surface of the ejection channel 71, the inner surface of each communication path 110, 111, the inner surface of each connection path 121, 122, and the inner surface of the manifold 123. The protective film 125 contains an organic insulating material such as a paraxylylene-based resin material (e.g., Parylene (registered trademark)) as an insulating material. The protective film 125 may be made of tantalum oxide (Ta2O5), silicon nitride (SiN), silicon carbide (SiC), silicon oxide (SiO2), diamond-like carbon, or the like, or may contain at least one of these.

[0061] <Nozzle plate 53> 3 to 5, the nozzle plate 53 is joined to the lower end surface of the feedback plate 52. The nozzle plate 53 has an array of nozzle holes (first nozzle holes 131 and second nozzle holes 132) that penetrate the nozzle plate 53 in the Z direction.

[0062] The plurality of first nozzle holes 131 are individually formed in the nozzle plate 53 at positions overlapping with the respective first communication passages 110 as viewed from the Z direction. That is, the first nozzle holes 131 are arranged at intervals in the X direction at the same pitch as the first communication passages 110. The first nozzle holes 131 communicate with the corresponding discharge channels 71 of the first tip module 51A through the corresponding first communication passages 110. Specifically, each first nozzle hole 131 is formed at the +Y side end of each first communication passage 110 at a position overlapping with the discharge channel 71 and the upstream wide portion 117a as viewed from the Z direction. Note that the first nozzle holes 131 may communicate with the first communication passages 110 at a position offset in the Y direction from the discharge channels 71 of the first tip module 51A.

[0063] The multiple second nozzle holes 132 are individually formed in the nozzle plate 53 at positions overlapping with the respective second communication passages 111 as viewed from the Z direction. That is, the second nozzle holes 132 are arranged at the same pitch as the second communication passages 111 and spaced apart in the X direction. The second nozzle holes 132 communicate with the corresponding discharge channels 71 of the second tip module 51B through the corresponding second communication passages 111. Specifically, each second nozzle hole 132 is formed at the -Y side end of each second communication passage 111 at a position overlapping with the discharge channel 71 and the upstream wide portion 117a as viewed from the Z direction. Note that the second nozzle holes 132 may communicate with the second communication passages 111 at a position offset in the Y direction from the discharge channel 71 of the second tip module 51B.

[0064] [Printer 1 operation method] Next, a case where characters, figures, etc. are recorded on the recording medium P using the printer 1 configured as described above will be described below. 1 are each fully filled with ink of a different color. The ink in the ink tanks 4 is then transferred to the inkjet head 5 via the ink circulation mechanism 6.

[0065] When the printer 1 is operated in this initial state, the recording medium P is conveyed to the +X side while being sandwiched between the rollers 11 and 12. At the same time as the recording medium P is conveyed, the carriage 29 moves in the Y direction, and the inkjet head 5 mounted on the carriage 29 moves back and forth in the Y direction.

[0066] The movement of each inkjet head 5 will now be described in detail. In a vertical circulation type head chip 50 such as that of the first embodiment, first, the pressure pump 24 and the suction pump 25 shown in FIG. 2 are operated to circulate ink through the circulation flow path 23. In this case, ink flowing through the ink supply pipe 21 flows into the common ink chamber 80 of each chip module 51 through the inlet port. The ink that has flowed into each common ink chamber 80 is supplied to each ejection channel 71 through the slit 81. The ink that has flowed into each ejection channel 71 passes through each communication path 110, 111 and each connection path 121, 122, gathers in the manifold 123, and is then discharged into the ink discharge pipe 22 through the outlet port. The ink discharged into the ink discharge pipe 22 is returned to the ink tank 4 and then supplied again to the ink supply pipe 21. In this way, ink is circulated between the inkjet head 5 and the ink tank 4.

[0067] When the carriage 29 starts reciprocating, a drive voltage is applied to the electrodes 87, 91 via the flexible substrate. At this time, the drive voltage is applied between the electrodes 87, 91 with the individual electrode 91 at drive potential Vdd and the common electrode 87 at reference potential GND. This causes thickness shear deformation in the two drive walls 75 that define the ejection channel 71, causing these two drive walls 75 to deform so as to protrude toward the non-ejection channel 72. That is, since the actuator plates 61, 101 of the first embodiment are made up of two piezoelectric substrates that are polarized in the thickness direction (Y direction) and are stacked, applying a drive voltage causes the drive walls 75 to bend and deform in a V shape around the midpoint in the Y direction. This causes the ejection channel 71 to deform as if it were bulging.

[0068] When the volume of the ejection channel 71 increases due to the deformation of the two drive walls 75, the ink in the common ink chamber 80 is guided into the ejection channel 71 through the slit 81. The ink guided into the ejection channel 71 then becomes a pressure wave that propagates into the ejection channel 71, and when this pressure wave reaches the nozzle holes 131 and 132, the drive voltage applied between the electrodes 87 and 91 is set to zero. As a result, the driving wall 75 returns to its original state, and the volume of the ejection channel 71, which had temporarily increased, returns to its original volume. This action increases the pressure inside the ejection channel 71, pressurizing the ink. As a result, ink can be ejected from the nozzle holes 131, 132. At this time, the ink is ejected as liquid droplets as it passes through the nozzle holes 131, 132. This makes it possible to record characters, images, etc. on the recording medium P, as described above. That is, in the head chip 50 of the first embodiment, a portion of the ink flowing through each of the communication paths 110, 111 is ejected through the nozzle holes 131, 132, while the remaining ink is returned to the manifold 123 through the connection paths 121, 122.

[0069] [Method for manufacturing head chip 50] Next, a description will be given of a method for manufacturing the above-mentioned head chip 50. Fig. 9 is a flowchart for explaining a method for manufacturing the head chip 50. For convenience, the following description will be given taking as an example a case where the head chip 50 is manufactured at the chip level.

[0070] As shown in FIG. 9, the head chip 50 includes a module fabrication process S1, a module stacking process S2, a feedback plate stacking process S3, a feedback plate processing process S4, a protective film formation process S5, and a nozzle plate stacking process S6. In the module fabrication step S1, a first chip module 51A and a second chip module 51B are fabricated.

[0071] 10 to 12 are process diagrams for explaining the method for manufacturing the head chip 50, and are cross-sectional views corresponding to FIG. 10, in the module stacking process S2, the chip modules 51A and 51B created in the module creation process S1 are bonded together. Specifically, with the bottom end surfaces of the chip modules 51A and 51B aligned, the back surfaces of the back plates 63 and 103 are bonded together. As a result, the back surface opening of the first connection path 121 is blocked by the second back plate 103, the back surface opening of the second connection path 122 is blocked by the first back plate 63, and the manifold 123 is formed by the first recess 123a and the second recess 123b. This forms a stack of the chip modules 51A and 51B.

[0072] As shown in FIG. 11, in the feedback plate lamination step S3, a feedback plate 52 is attached to the lower end surface of the stack of chip modules 51A and 51B. 12, in the feedback plate processing step S4, communicating passages 110, 111 are formed in the portions of the feedback plate 52 that overlap with the discharge channels 71 when viewed from the Z direction. The communicating passages 110, 111 are formed by, for example, laser processing the feedback plate 52. Note that the communicating passages 110, 111 are all formed by the same method. Therefore, hereinafter, a method for forming the communicating passages 110, 111 will be described using the first communicating passage 110 as an example.

[0073] The feedback plate processing step S4 includes a connection portion forming step S41, an upstream opening forming step S42, and a downstream opening forming step S43.

[0074] 13 to 28 are process diagrams of the connection portion forming step S41. Of FIGS. 13 to 28, FIGS. 13 to 20 are bottom views of a portion of feedback plate 52 corresponding to portion A in FIG. 6. Of FIGS. 13 to 28, FIGS. 21 to 28 are cross-sectional views of feedback plate 52. The correspondence between FIGS. 21 to 28 and FIGS. 13 to 20 is as shown by the cross-sectional indication lines indicated by Roman numerals in FIGS. 13 to 20. In the connection portion forming step S41, the connection portion 117 is formed by a first laser irradiation step S411 and a second laser irradiation step S412. That is, the connection portion 117 is made up of an outer portion 200 (see FIGS. 19 and 26) remaining after the first laser irradiation step S411 and an additional laser irradiation mark (second laser irradiation mark) 201 (see FIG. 28) remaining after the second laser irradiation step S412.

[0075] As shown in FIGS. 13 and 21 , in the first laser irradiation step S411, a laser beam is irradiated onto the surface (lower surface) of the feedback plate 52 facing the −Z side to form an outer shape portion 200 that defines the outer shape of the connection portion 117 in a planar view. Specifically, the Y direction is the laser scanning direction and the X direction is the pitch direction (row direction), and the laser beam is scanned across multiple rows. Therefore, the length of the connection portion 117 in the Y direction can be adjusted according to the scanning range of the laser beam. Meanwhile, the width of the connection portion 117 in the X direction can be adjusted by the number of rows of the center row of laser beams irradiated between the laser irradiation of the start row and the laser irradiation of the last row, the laser diameter of the laser beam, the offset amount of the laser beams between adjacent rows, etc. In the first embodiment, the laser diameters of the rows are all the same (for example, approximately 10 μm). However, the laser diameter may be changed for each row.

[0076] In the first laser irradiation step S411, first, the start row laser beam L1 is irradiated. Specifically, the start row laser beam L1 is scanned along the Y direction at a position on the underside of the feedback plate 52 corresponding to the −X side end of the connection portion 117, thereby forming the start row irradiation mark (first laser irradiation mark) 210 shown in FIGS. 14 and 22. As shown in FIG. 14, the start row irradiation mark 210 extends linearly along the Y direction in a plan view. As shown in FIG. 22, the start row irradiation mark 210 is recessed in a semicircular shape relative to the underside of the feedback plate 52 when viewed from the Y direction. Note that the width of the start row irradiation mark 210 in the X direction is slightly larger than the laser diameter because the heat effect of the start row laser beam L1 propagates to an area outside the laser diameter.

[0077] Incidentally, after laser irradiation, there is a possibility that a raised portion (hereinafter referred to as a "wrinkle") may be formed relative to the opening edge of the laser irradiation mark. In this case, for example, after the formation of start row irradiation mark 210, a peripheral wrinkle 211 that rises from the underside of feedback plate 52 is formed at the opening edge of start row irradiation mark 210. Peripheral wrinkle 211 extends around the entire periphery of start row irradiation mark 210 so as to surround start row irradiation mark 210.

[0078] Next, as shown in FIGS. 15 and 23, the second row (center row) of laser light L2 is scanned to form the center row irradiation mark (first laser irradiation mark) 215 shown in FIGS. 16 and 24. As shown in FIGS. 15 and 23, the center row laser light L2 is scanned by offsetting the center of the laser diameter of the center row laser light L2 toward the +X side with respect to the center of the laser diameter of the previous row (start row laser light L1). In the first embodiment, the offset amount of the center row laser light L2 is, for example, half the laser diameter (half the pitch). However, the offset amount of the center row laser light L2 can be changed as appropriate as long as it is within a range in which the start row irradiation mark 210 and the center row irradiation mark 215 partially overlap each other.

[0079] The center row irradiation marks 215 are formed so as to overlap the +X side end of the previous row of laser irradiation marks (start row irradiation marks 210), thereby forming an intermediate recess 216 together with the start row irradiation marks 210. As shown in FIG. 16 , the center row irradiation marks 215 extend parallel to the start row irradiation marks 210 while being connected to them in a plan view. As shown in FIG. 24 , the center row irradiation marks 205 are recessed in an arc shape relative to the underside of the feedback plate 52 when viewed from the Y direction. Note that the overlapping portion of the intermediate recess 216 between the start row irradiation marks 210 and the center row irradiation marks 215 is deeper than the start row irradiation marks 210. In the first embodiment, a case where there is only one row of center row irradiation marks 215 will be described; however, the number of rows of center row irradiation marks 215 can be changed depending on the width of the connection portion 117 in the X direction.

[0080] Of the outer circumferential twist 211 formed by the scanning of the start row laser beam L1, the portion that overlaps the scanning range of the center row laser beam L2 is removed by irradiation with the center row laser beam L2. Meanwhile, new twists may be formed around the portion of the feedback plate 52 that is irradiated only with the center row laser beam L2 by irradiation with the center row laser beam L2. As a result, the outer circumferential twist 211 remains on the outer circumferential edge of the intermediate recess 216 so as to surround the periphery of the intermediate recess 216. Furthermore, a first inner twist 220 that protrudes from the bottom surface of the intermediate recess 216 is formed at the boundary between the center row irradiation mark 215 and the start row irradiation mark 210 on the bottom surface of the intermediate recess 216.

[0081] Next, as shown in FIGS. 17 and 25, the third row (final row) laser light L3 is scanned. In the first embodiment, the offset amount of the final row laser light L3 relative to the center row laser light L2 is the same as the offset amount of the center row laser light L2 relative to the start row laser light L1, for example. This forms the final row irradiation mark (first laser irradiation mark) 221 shown in FIGS. 18 and 26. The final row irradiation mark 221 is formed so as to overlap the +X side end of the previous row laser irradiation mark (center row irradiation mark 215), thereby forming the outline portion 200 together with the start row irradiation mark 210 and the center row irradiation mark 215. The outline portion 200 forms the outline of the connection portion 117 in a planar view. As shown in FIG. 18, the final row irradiation mark 221 extends parallel to the center row irradiation mark 205 while being connected to the center row irradiation mark 205 in a planar view. As shown in FIG. 26, the final row irradiation mark 221 is recessed in an arc shape with respect to the lower surface of the feedback plate 52 when viewed from the Y direction.

[0082] Of the outer circumferential wrinkles 211 formed by the scanning of the start row laser beam L1 and the center row laser beam L2, the portion that overlaps the scanning range of the last row laser beam L3 is removed by irradiation with the last row laser beam L3. Meanwhile, a new wrinkle may be formed around the portion of the feedback plate 52 that is irradiated only with the last row laser beam L3 by irradiation with the last row laser beam L3. As a result, the outer circumferential wrinkles 211 remain on the outer periphery of the outer portion 200 so as to surround the periphery of the outer portion 200. Note that a second inner wrinkle 222 that protrudes from the bottom surface of the outer portion 200 is formed at the boundary between the center row irradiation mark 205 and the last row irradiation mark 221. This completes the first laser irradiation step S411.

[0083] Incidentally, after the first laser irradiation step S411, burrs 230 may be present on the inner surface of the outer portion 200. Burrs 230 are likely to adhere to the inner surface of existing irradiation marks (e.g., the start row irradiation mark 210) along the scanning direction due to the scattering of melted portions caused by the laser light, for example, during the formation of the center row irradiation mark 215 or the final row irradiation mark 221. In the illustrated example, the burrs 230 protrude from the feedback plate 52 through the opening of the outer portion 200. That is, when the width of a recess (e.g., the connection portion 117) to be formed by laser processing is wider than the laser diameter of one row, multiple rows of laser irradiation marks are formed in the width direction (X direction) of the recess by overlapping portions of the laser irradiation marks. In this case, there is an area in part (the -X side end) of the start row irradiation mark 210 where the laser light is not irradiated overlappingly. Burrs 230 are likely to remain in the area where the laser light is not irradiated overlappingly.

[0084] Therefore, as shown in Fig. 19 and Fig. 27, the second laser irradiation step S412 is performed to mainly remove the burrs 230. The second laser irradiation step S412 is performed by scanning the additional processing laser beam L4 along the edge of the opening on the -X side of the connection portion 117 (outer portion 200). Specifically, the additional processing laser beam L4 is set to have the same laser diameter as the laser beam used in the first laser irradiation step S411. However, the laser diameter may be different between the first laser irradiation step S411 and the second laser irradiation step S412.

[0085] The irradiation position of the additional processing laser beam L4 in the X direction is performed so that the center of the laser diameter of the additional processing laser beam L4 coincides with the center of the start row laser beam L1. The scanning range of the additional processing laser beam L4 in the Y direction is the same as the scanning range of the start row laser beam. When the second laser irradiation step S412 is performed under these conditions, the additional processing laser beam L4 is irradiated along the scanning trajectory of the start row laser beam L1. As a result, burrs 230 are removed, as shown in FIGS. 20 and 28 . Furthermore, additional processing laser irradiation marks 201 are formed by the additional processing laser beam L4 in the locations of the outer portion 200 where the start row irradiation marks 210 were present. The additional processing laser irradiation marks 201, together with the outer portion 200, form the connection portion 117. In the connection portion 117, an outer peripheral twist 211 remains at the opening edge, while an internal twist 225 remains at the bottom surface. The internal twist 225 is a twist formed at the boundary of the additional laser irradiation mark 201 on the bottom surface of the outer portion 200 .

[0086] Subsequently, in the upstream opening forming step S42, a region of the bottom surface of the connection portion 117 where the upstream opening 115 is to be formed is subjected to, for example, laser processing so that the feedback plate 52 penetrates through the region. As a result, the upstream opening 115 is formed. In the downstream opening forming step S43, for example, laser processing is performed on the bottom surface of the connecting portion 117 in a region where the downstream opening 116 is to be formed so that the feedback plate 52 penetrates through the region. This forms the downstream opening 116. Note that when the upstream opening 115 and the downstream opening 116 are formed by laser processing, the internal twist 225 may be removed. This completes the feedback plate processing step S4 (state in FIG. 12).

[0087] In the first embodiment, the communicating paths 110, 111 are formed after the feedback plate 52 is bonded to the chip modules 51A, 51B, but this configuration is not limited thereto. The communicating paths 110, 111 may be formed in the feedback plate 52 beforehand, and then the feedback plate 52 may be bonded to the chip modules 51A, 51B. Furthermore, in the first embodiment, the method in which the first laser irradiation step S411 and the second laser irradiation step S412 are performed consecutively has been described, but this configuration is not limited thereto. For example, after the first laser irradiation step S411, the upstream opening forming step S42 and the downstream opening forming step S43 may be performed, and the second laser irradiation step S412 may be performed at the end of the feedback plate processing step S4.

[0088] In the protective film forming process S5, a protective film 125 is formed on the inner surface of the common ink chamber 80, the inner surface of the slit 81, the inner surface of the ejection channel 71, the inner surface of each communication path 110, 111, the inner surface of each connection path 121, 122, and the inner surface of the manifold 123. The protective film 125 is formed by depositing a film of a paraxylylene-based resin material using, for example, chemical vapor deposition (CVD) or the like.

[0089] In the nozzle plate laminating step S6, the nozzle plate 53 is attached to the lower surface of the feedback plate 52. The head chip 50 is thus completed. When the head chip 50 is manufactured at the wafer level, the actuator plate wafer, the cover plate wafer, and the back plate wafer are subjected to the same process as the module creation process S1 described above to form a wafer stack. The wafer stack is then diced into individual pieces, thereby extracting multiple chip modules 51A, 51B. The chip modules 51A, 51B extracted from the wafer stack are then subjected to the module stacking process S2 and subsequent processes, thereby completing the head chip 50.

[0090] As described above, head chip 50 according to the first embodiment has connection portion (recess) 117 formed by outer portion 200 (irradiation marks 210, 215, 221), and is provided with a feedback plate (flow path member) 52 through which ink flows in connection portion 117, and a nozzle plate (joining member) 53 joined to feedback plate 52 so as to close connection portion 117. Additional laser irradiation marks 201 are formed on feedback plate 52, extending along the opening edge of connection portion 117. According to this configuration, additional laser irradiation marks 201 are formed along the opening edge of the connection portion 117, thereby reducing unnecessary processing residues (such as burrs 230) remaining on the opening edge of the connection portion 117 (outer portion 200) after the first laser irradiation step S411. This makes it possible to prevent unnecessary processing residues from getting caught when joining the feedback plate 52 and the nozzle plate 53. As a result, ink leakage between the feedback plate 52 and the nozzle plate 53 is suppressed, and the joining strength between the feedback plate 52 and the nozzle plate 53 is ensured. Furthermore, reducing unnecessary processing residues within the connection portion 117 makes it possible to reduce unevenness within the connection portion 117. This reduces the flow resistance of ink flowing through the connection portion 117, allowing ink to flow smoothly through the connection portion 117.

[0091] In the head chip 50 according to the first embodiment, the communication paths 110, 111 include a connection portion 117 that opens only on the surface of the feedback plate 52 facing the -Z side (the surface facing the joining member in the thickness direction), and an upstream opening 115 and a downstream opening 116 (penetrating portions) that open on the bottom surface of the connection portion 117 and penetrate the feedback plate 52 in the Z direction. The additional processing laser irradiation mark 201 extends at least along the opening edge of the connection portion 117. According to this configuration, there is a possibility that unnecessary machining residue remaining on the opening edge of the connection portion 117 will be exposed on the joining surface of the feedback plate 52 with the nozzle plate 53. Therefore, by forming the additional laser irradiation marks 201 at least along the opening edge of the connection portion 117, it is possible to prevent the unnecessary machining residue from being exposed on the joining surface of the feedback plate 52 with the nozzle plate 53.

[0092] In the head chip 50 according to the first embodiment, the irradiation marks 210, 215, and 221 constituting the outer portion 200 are formed in multiple rows in the X direction, and the additional processing laser irradiation marks 201 extend in the Y direction along the start row irradiation marks (outer laser irradiation marks) 210. With this configuration, unnecessary processing residues such as burrs 230 fly off during laser processing, and are therefore likely to adhere to the inner surface of the existing laser irradiation mark when laser processing is performed for the second or subsequent rows. In particular, since the start row irradiation mark 210 forms the opening of the connection portion 117 along its extension direction, if unnecessary processing residues remain on the inner surface of the start row irradiation mark 210, this is likely to lead to the ink leak and poor connection described above. Therefore, by forming the additional laser irradiation mark 201 along the start row irradiation mark 210 among the multiple irradiation marks 210, 215, and 221, it is possible to effectively reduce unnecessary processing residues remaining along the extension direction of the start row irradiation mark 210.

[0093] In head chip 50 according to the first embodiment, connection portion 117 is configured to be formed in a rectangular shape with the Y direction as the longitudinal direction and the X direction as the lateral direction when viewed from the Z direction. According to this configuration, the longitudinal direction of the connection portion 117 and the extending direction of the additional laser irradiation marks 201 coincide with each other, so that unnecessary processing residues along the longitudinal direction of the connection portion 117 can be reduced.

[0094] In the head chip 50 according to the first embodiment, the communicating paths 110, 111 include an upstream opening (first through-portion) 115 and a downstream opening (second through-portion) 116 that is spaced apart from the upstream opening 115 in the Y direction and that communicates with the upstream opening 115 through a connection portion 117. Chip modules (chip bodies) 51A, 51B are joined to the opposite side of the nozzle plate 53 with respect to the feedback plate 52, and each chip module (chip body) 51A, 51B has formed therein an ejection channel (pressure chamber) 71 that communicates with the communicating paths 110, 111 through the upstream opening 115 and connection paths (circulation paths) 121, 122 that communicate with the communicating paths 110, 111 through the downstream opening 116, and the nozzle plate 53 has formed therein nozzle holes (ejection holes) 131, 132 that eject ink from the communicating paths 110, 111 to the outside. According to this configuration, the flow path member communicates with the nozzle holes 131, 132 and also functions as a feedback plate 52 that allows ink to circulate between the ejection channel 71 and the connection paths 121, 122. In this case, in the head chip 50 according to the first embodiment, unevenness within the communication paths 110, 111 can be suppressed, and therefore ink can smoothly circulate between the nozzle holes 131, 132, the ejection channel 71, and the connection paths 121, 122 through the communication paths 110, 111.

[0095] The inkjet head 5 and printer 1 according to the first embodiment include the head chip 50 described above, and therefore, it is possible to provide an inkjet head 5 and printer 1 that are highly reliable.

[0096] (Second embodiment) 29 to 32 are process diagrams of the second laser irradiation step S412 according to the second embodiment. Of Figs. 29 to 32, Figs. 29 and 30 are bottom views of a portion corresponding to portion A in Fig. 6. Of Figs. 29 to 32, Figs. 31 and 32 are cross-sectional views of feedback plate 52.

[0097] The second embodiment differs from the first embodiment in that the second laser irradiation step S412 is performed with the center of the additional processing laser beam L4 positioned at a position shifted in the X direction from the center of the start row laser beam L1. Specifically, in the second laser irradiation step S412 according to the second embodiment, the additional processing laser beam L4 is irradiated so that the additional processing laser irradiation mark 201 is formed on the inner side in the X direction (+X side) of the opening edge of the connection portion 117 (start row irradiation mark 210). In this case, it is preferable to irradiate the additional processing laser beam L4 so that the center of the laser diameter of the additional processing laser beam L4 is positioned between the center of the laser diameter of the start row laser beam L1 and the center of the laser diameter of the central row laser beam L2. However, the center of the laser diameter of the additional processing laser beam L4 can be changed as appropriate as long as it is at least a position where the heat of the additional processing laser beam L4 propagates to the burr 230.

[0098] Then, the burrs 230 are removed by the effect of heat propagated around the additional processing laser beam L4. That is, when the additional processing laser irradiation mark 201 is formed, the burrs 230 and the like protruding from the opening edge of the connection portion 117 can be effectively removed. Furthermore, the additional processing laser irradiation mark 201 is formed so that its center in the X direction is located in a portion located between the center in the X direction of the start row irradiation mark 210 and the center in the X direction of the central row irradiation mark 215. In other words, the center in the X direction (deepest part) of the additional processing laser irradiation mark 201 is located at a position shifted from the centers in the X direction (deepest parts) of the adjacent irradiation marks 210, 215.

[0099] In the head chip 50 according to the second embodiment, the center of the additional processing laser irradiation mark 201 in the X direction is positioned more inward in the X direction than the center of the start row irradiation mark 210 in the X direction. According to this configuration, by positioning the center of the additional laser irradiation mark 201 in the X direction more inward in the X direction than the center of the start row irradiation mark 210 in the X direction, the burrs 230 can be removed by the effect of heat propagating around the additional laser beam L4. In this case, the effect of heat propagating to the opening edge of the outer portion 200 (connection portion 117) can be suppressed compared to when the additional laser beam L4 is scanned along the same trajectory as the scanning trajectory of the start row laser beam L1. This suppresses the increase in the peripheral deviation 211 caused by the additional laser beam L4. Therefore, when the feedback plate 52 and the nozzle plate 53 are joined, the peripheral deviation 211 can be suppressed from being caught as an unnecessary processing residue. As a result, ink leakage between the feedback plate 52 and the nozzle plate 53 is suppressed, and the joining strength between the feedback plate 52 and the nozzle plate 53 can be ensured. Furthermore, it is possible to prevent the inner circumferential twist from being exacerbated by misalignment of the centers in the X direction of the additional processing laser irradiation mark 201, the start row irradiation mark 210, and the center row irradiation mark 215. As a result, it is possible to prevent unevenness within the connection portion 117, thereby reducing the flow resistance of ink flowing through the communicating paths 110, 111 and allowing ink to flow smoothly through the communicating paths 110, 111.

[0100] (Third embodiment) In the third embodiment, the method of forming upstream opening 115 that constitutes the through portion differs from the above-described embodiments in that additional laser irradiation is performed. Fig. 33 is a flowchart for explaining a method of manufacturing head chip 50 according to the third embodiment. Figs. 34 to 49 are process diagrams of upstream opening forming step S42. Of Figs. 34 to 49, Figs. 34 to 41 are bottom views of a portion of feedback plate 52 that corresponds to portion A in Fig. 6. Of Figs. 34 to 49, Figs. 42 to 49 are cross-sectional views of feedback plate 52. The correspondence between Figs. 42 to 49 and Figs. 34 to 41 is as shown by the cross-sectional indication lines indicated by Roman numerals in Figs. 34 to 41.

[0101] 33, the upstream opening forming step S42 includes a first laser irradiation step S421 and a second laser irradiation step S422. In the following description, the same content as in the first embodiment will be omitted as appropriate.

[0102] In the first laser irradiation step S421, a laser beam is irradiated onto the bottom surface of the connection portion 117 of the feedback plate 52, thereby forming the outline of the upstream opening 115 in a plan view. Specifically, the Y direction is the laser scanning direction, and the X direction is the pitch direction (row direction), thereby scanning the laser beam across multiple rows. As shown in FIGS. 34 and 42, in the first laser irradiation step S421, a start row laser beam L1 is irradiated. Specifically, a laser beam is scanned along the Y direction at a position on the bottom surface of the connection portion 117 corresponding to the −X side end of the upstream opening 115, thereby forming a start row irradiation mark (first laser irradiation mark) 300 shown in FIGS. 35 and 43. As shown in FIG. 35, the start row irradiation mark 300 extends linearly along the Y direction in a plan view. As shown in FIG. 43, the start row irradiation mark 300 penetrates the feedback plate 52 via the connection portion 117. After the start row irradiation mark 300 is formed, a circumferential twisted portion 301 that rises from the bottom surface of the connection portion 117 is present at the opening edge of the start row irradiation mark 300 .

[0103] Next, as shown in FIGS. 36 and 44, the second row (center row) of laser light L2 is scanned. The center row of laser light L2 is scanned with the center of the laser diameter offset toward the +X side relative to the center of the laser diameter of the previous row (start row laser light L1). This forms the center row irradiation marks 305 shown in FIGS. 37 and 45. The center row irradiation marks 305 are formed so as to overlap the +X side end of the previous row of laser irradiation marks (start row irradiation marks 300), thereby forming intermediate recesses 306 together with the start row irradiation marks 300. As shown in FIG. 37, the center row irradiation marks 305 extend parallel to the start row irradiation marks 300 while being connected to them in a planar view. As shown in FIG. 45, the center row irradiation marks 305 penetrate the feedback plate 52 together with the start row irradiation marks 300. In the third embodiment, a case will be described in which the central row irradiation marks 305 are in one row, but the number of rows of the central row irradiation marks 305 can be changed depending on the width of the upstream opening 115 in the X direction.

[0104] Next, as shown in FIGS. 38 and 46, the laser light L3 of the final row (third row) is scanned. In the third embodiment, the offset amount of the final row laser light L3 is the same as the offset amount of the center row laser light L2 relative to the start row laser light L1, for example. This forms the final row irradiation marks 311 shown in FIGS. 39 and 47. The final row irradiation marks 311 are formed so as to overlap the +X side end of the previous row laser irradiation marks (center row irradiation marks 305), and thus penetrate the feedback plate 52 together with the start row irradiation marks 300 and the center row irradiation marks 305. The final row irradiation marks 311 extend parallel to the center row irradiation marks 305 while being connected to them. This completes the first laser irradiation step S421. That is, in the first laser irradiation step S421, an outer shape portion 315 having the same outer shape as the upstream opening 115 in plan view is formed.

[0105] After the first laser irradiation process S421, there is a possibility that the inner surface of the outer portion 315 (upstream opening 115) may have a portion melted by, for example, the central row laser light L2 when forming the central row irradiation mark 305, adhering to the inner surface of the starting row irradiation mark 300 as a burr 320.

[0106] Therefore, as shown in FIGS. 40 and 48, the second laser irradiation step S422 is performed to mainly remove the burrs 320. The second laser irradiation step S422 is performed by irradiating the additional processing laser beam L4 along the opening edge on the -X side of the outer portion 315 (upstream opening 115). Specifically, the center of the laser diameter of the additional processing laser beam L4 coincides with the center of the start row laser beam L1. Meanwhile, the scanning range in the Y direction of the additional processing laser beam L4 is the same as the scanning range of the start row laser beam L1. When the second laser irradiation step S422 is performed under these conditions, the additional processing laser beam is irradiated along the scanning trajectory of the start row laser beam L1. As a result, the burrs 320 are removed, as shown in FIGS. 41 and 49. Furthermore, the additional processing laser irradiation marks (second laser irradiation marks) 321 are formed by the additional processing laser beam L4 at the locations of the outer portion 315 where the start row irradiation marks 300 were present. The additional laser irradiation mark 321 forms the upstream opening 115 together with the laser irradiation marks 300 , 305 , and 311 .

[0107] In the second embodiment, by performing the first laser irradiation step S421 and the second laser irradiation step S422 on the upstream opening 115 as the through-hole, the same effects as those of the first embodiment described above can be achieved. Furthermore, by removing burrs 320 before bonding feedback plate 52 and nozzle plate 53, it is possible to prevent burrs 320 from falling off and remaining in the ink after bonding feedback plate 52 and nozzle plate 53. Note that, in the third embodiment, a case has been described in which the manufacturing method for head chip 50 according to the present disclosure is applied to upstream opening 115, but it is also possible to apply the manufacturing method for head chip 50 according to the present disclosure to processing downstream opening 116.

[0108] (Fourth embodiment) 50 to 53 are process diagrams of the second laser irradiation step S422 according to the fourth embodiment. Of Figs. 50 to 53, Figs. 50 and 51 are bottom views of a portion corresponding to portion A in Fig. 6. Of Figs. 50 to 53, Figs. 52 and 53 are cross-sectional views of feedback plate 52.

[0109] The fourth embodiment differs from the third embodiment in that the second laser irradiation step S422 is performed with the center of the additional processing laser beam L4 positioned at a position shifted in the X direction from the center of the start row laser beam L1. Specifically, in the second laser irradiation step S422 according to the fourth embodiment, the additional processing laser beam L4 is irradiated onto a portion of the upstream opening 115 positioned inside the opening edge in the X direction. In this case, the additional processing laser beam L4 is preferably irradiated so that the center of the laser diameter is positioned between the center of the laser diameter of the start row laser beam L1 and the center of the laser diameter of the central row laser beam L2. However, the center of the laser diameter of the additional processing laser beam L4 can be changed as appropriate as long as it is at least a position where the heat of the additional processing laser beam L4 propagates to the burr 320.

[0110] As a result, the burrs 320 are removed by the effect of heat propagated around the additional processing laser beam L4. That is, the additional processing laser beam L4 can effectively remove the burrs 320 and the like that protrude from the opening edge of the upstream opening 115. In addition, in the fourth embodiment, additional processing laser irradiation marks 321 formed by the effect of heat from the additional processing laser beam L4 remain in the portions of the inner surface of the upstream opening 115 that face the +X side and that face inward in the Y direction and are positioned between the start row irradiation marks 300 and the center row irradiation marks 305.

[0111] In the fourth embodiment, as in the second embodiment described above, it is possible to prevent the peripheral wrinkle 301 remaining on the opening edge of the upstream opening 115 from being exacerbated by the additional laser irradiation marks 321. This makes it possible to reduce irregularities within the communicating passages 110, 111. This reduces the flow resistance of ink flowing through the communicating passages 110, 111, allowing ink to flow smoothly within the communicating passages 110, 111.

[0112] (Other variations) The technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present disclosure. For example, in the above-described embodiment, the inkjet printer 1 has been described as an example of a liquid jet recording apparatus, but the liquid jet recording apparatus is not limited to a printer. For example, a fax machine, an on-demand printer, etc. may also be used. In the above-described embodiment, a configuration in which the inkjet head moves relative to the recording medium during printing (a so-called shuttle machine) has been described as an example, but the present disclosure is not limited to this configuration. The configuration according to the present disclosure may also be employed in a configuration in which the inkjet head is fixed and the recording medium moves relative to the inkjet head (a so-called fixed head machine). In the above-described embodiment, the recording medium P is paper, but this is not limiting. The recording medium P is not limited to paper, and may be a metal material, a resin material, or food. In the above-described embodiment, a configuration in which the liquid jet head is mounted on a liquid jet recording apparatus has been described, but the present invention is not limited to this configuration. That is, the liquid jetted from the liquid jet head is not limited to the liquid that lands on a recording medium, but may be, for example, a medicinal liquid to be mixed into a medicine, a food additive such as a seasoning or flavoring to be added to food, or an aromatic to be sprayed into the air.

[0113] In the above-described embodiment, the Z direction coincides with the direction of gravity, but the invention is not limited to this configuration, and the Z direction may be aligned with the horizontal direction. In the above-described embodiment, a configuration has been described in which ink is ejected by deforming the actuator plate in a direction that expands the volume of the ejection channel by applying a voltage and then restoring the actuator plate to its original shape (so-called pull ejection), but this configuration is not limited to this. The head chip according to the present disclosure may also be configured to eject ink by deforming the actuator plate in a direction that reduces the volume of the ejection channel by applying a voltage (so-called push ejection). When push ejection is performed, the actuator plate is deformed by applying a drive voltage so as to bulge toward the inside of the ejection channel. This reduces the volume within the ejection channel, increasing the pressure within the ejection channel, and ink within the ejection channel is ejected to the outside through the nozzle hole. When the drive voltage is reduced to zero, the actuator plate is restored to its original shape. As a result, the volume within the ejection channel returns to its original shape.

[0114] In the above embodiment, the configuration in which the chip modules 51A and 51B are stacked has been described, but the configuration is not limited to this. The head chip 50 may be configured with only the first chip module 51A. In the above-described embodiment, an edge chute type head chip has been described as an example, but the present disclosure is not limited to this configuration. For example, the present disclosure may be applied to a so-called side chute type head chip 50 that ejects ink from the center of the ejection channel 71 in the extension direction. The head chip may also be a so-called roof chute type head chip, in which the direction of pressure applied to the ink and the direction of ink ejection are the same. In the case of a roof chute type head chip, the part facing the pressure chamber that contains the ink and that deforms to expand or contract the pressure chamber functions as the drive unit.

[0115] In the above-described embodiment, the scanning direction of the laser light in the first laser irradiation step and the scanning direction of the laser light in the second laser irradiation step are the same, but the present invention is not limited to this configuration. The scanning direction of the laser light in the first laser irradiation step and the scanning direction of the laser light in the second laser irradiation step may intersect with each other. In the above-described embodiment, the laser irradiation for additional processing is performed only along the edge of the opening formed by the starting row irradiation marks, but this is not limited to this configuration. The laser irradiation for additional processing may be performed along the entire periphery of the edge of the opening formed by the first laser irradiation marks.

[0116] In the above-described embodiments, only connecting portion 117 is formed by employing the manufacturing method for head chip 50 according to the present disclosure in the first embodiment, and only upstream opening 115 (or downstream opening 116) is formed by employing the manufacturing method for head chip 50 according to the present disclosure in the third embodiment, but this configuration is not limiting. The manufacturing method for head chip 50 according to the present disclosure may be employed for both connecting portion 117 and various openings 115, 116. In the above-described embodiment, the recess according to the present disclosure has the connection portion 117 as a non-penetrating portion and the openings 115, 116 as penetrating portions, but the present disclosure is not limited to this configuration. The recess may be composed of only non-penetrating portions or only penetrating portions.

[0117] In the above-described embodiment, the feedback plate 52 is described as a flow path member and the nozzle plate 53 is described as a joining member, but the present disclosure is not limited to this configuration. The head chip according to the present disclosure can be applied to various members constituting a head chip, with a member in which a recessed portion serving as a flow path is formed as a flow path member and a member joined to the flow path member as a joining member.

[0118] In addition, within the scope of the present disclosure, the components in the above-described embodiments may be replaced with well-known components as appropriate, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0119] 1: Printer (liquid jet recording device) 5: Inkjet head (liquid jet recording head) 50: Head chip 51A: First chip module (chip body) 51B: Second chip module (chip body) 52: Return plate (flow path component) 53: Nozzle plate (jointing material) 71: Discharge channel (pressure chamber) 110: First communication passage (recess) 111: Second communication passage (recess) 115: Upstream opening (first penetration, penetration, recess) 116: downstream opening (second penetration portion, penetration portion, recess) 117: Connection part (non-penetrating part, recessed part) 121: First connecting route (circulation route) 122: Second connecting route (circulation route) 131: 1st nozzle hole (injection hole) 132:Second nozzle hole (injection hole) 201: Additional laser irradiation marks (second laser irradiation marks) 210: Starting row irradiation mark (first laser irradiation mark, outer laser irradiation mark) 215: Center row irradiation mark (first laser irradiation mark) 221: Final row irradiation mark (first laser irradiation mark) 300: Starting row irradiation marks (first laser irradiation marks, outer laser irradiation marks) 305: Center row irradiation marks (first laser irradiation marks) 311: Final row irradiation mark (first laser irradiation mark) 321: Additional laser irradiation marks (second laser irradiation marks)

Claims

1. a flow path member having a recess formed by a first laser irradiation mark, the flow path member having a liquid flowing through the recess; a joining member joined to the flow path member so as to close the recess, The head chip has a second laser irradiation mark formed on the flow path member, the second laser irradiation mark extending along the opening edge of the recess.

2. The recessed portion is a non-penetrating portion that opens only on a surface of the flow path member that faces the joining member in a thickness direction; a through-portion that opens on a bottom surface of the non-through portion and penetrates the flow path member in the thickness direction, The head chip according to claim 1 , wherein the second laser irradiation mark extends at least along an edge of an opening of the non-penetrating portion.

3. the first laser irradiation marks extend in a first direction intersecting a thickness direction of the flow path member, and are formed in a plurality of rows in a second direction intersecting the first direction as viewed from the thickness direction, 3. The head chip according to claim 1, wherein the second laser irradiation mark extends in the first direction along an outer laser irradiation mark that is located outermost in the second direction among the plurality of first laser irradiation marks.

4. The head chip according to claim 3 , wherein a center of the second laser irradiation mark in the second direction is located more inward in the second direction than a center of the outer laser irradiation mark in the second direction.

5. The head chip according to claim 3 , wherein the recess is formed in a rectangular shape with the first direction as a longitudinal direction and the second direction as a lateral direction when viewed from the thickness direction.

6. The recessed portion is a non-penetrating portion that opens only on a surface of the flow path member that faces the joining member in a thickness direction; a through-portion that opens on a bottom surface of the non-through portion and penetrates the flow path member in the thickness direction, The through portion is A first penetration portion; a second penetration portion provided apart from the first penetration portion in the first direction and communicating with the first penetration portion through the non-penetrating portion, a chip body is joined to the opposite side of the joining member with respect to the flow path member in the thickness direction, the chip body having a pressure chamber communicating with the inside of the recess through the first through-portion and a circulation path communicating with the inside of the recess through the second through-portion; The head chip according to claim 3 , wherein the joining member has an ejection hole formed therein for ejecting the liquid in the recess to the outside.

7. A liquid jet head comprising the head chip according to claim 1 or 2.

8. A liquid jet recording apparatus comprising the liquid jet head according to claim 7.

9. a flow path member having a recess formed therein through which a liquid flows; a joining member joined to the flow path member so as to close the recess, a first laser irradiation step of irradiating a first laser beam onto a joining surface of the flow path member with the joining member, thereby forming an outer shape of the recess by a first laser irradiation mark; A method for manufacturing a head chip, comprising: a second laser irradiation step of irradiating a second laser beam along the opening edge of the recess to form a second laser irradiation mark along the opening edge of the recess.

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