Liquid passage member and manufacturing method of the same

Abstract

To provide a liquid passage member which enables improvement of accuracy of quality determination of a welding portion, and to provide a manufacturing method of the fluid passage member.SOLUTION: An ink branch passage member 70 includes: a first member 71; a second member 72 laminated on the first member 71 and forming a passage 73 with the first member 71; and a welding part 79 to which the first member 71 and the second member 72 are welded. The first member 71 is formed of a material which absorbs a laser beam L1. The second member 72 is formed of a material which transmits the laser beam L1 and visible light. Surface roughening is performed on a first surface 72s1 which faces the first member 71 of the second member 72.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a liquid flow path member and a method for manufacturing a liquid flow path member. [Background technology]

[0002] Conventionally, a technique for forming a liquid flow path member by laser welding for an inkjet printer, etc., has been known. For example, Patent Document 1 discloses a flow path member formed by welding two members together. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-47599 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the flow path member described in Patent Document 1 has a problem in that it is difficult to improve the accuracy of determining whether a welded portion is good or bad. Specifically, the quality of the weld at the welded portion between the first and second members is an important quality factor in terms of airtightness of the flow path. Therefore, the welded portion may be imaged by irradiating it with an inspection light and then binarizing the image to determine whether the weld is good or bad. In this case, the welded portion is imaged through a second member such as a translucent resin. Depending on the shape of the object being inspected and the orientation at the time of imaging, the contrast between the welded portion and its surroundings, i.e., the boundary between the black and white portions, may become blurred. This blurred boundary may result in erroneous determination of the quality of the welded portion. In other words, there has been a need for a liquid flow path member that improves the accuracy of determining whether a welded portion is good or bad. [Means for solving the problem]

[0005] The liquid flow path member comprises a first member, a second member laminated on the first member to form a flow path between the first member and the second member, and a welded portion where the first member and the second member are welded together, wherein the first member is formed of a material that absorbs laser light, and the second member is formed of a material that transmits the laser light and visible light, and a first surface of the second member that faces the first member is subjected to a roughening treatment.

[0006] The method for manufacturing a liquid flow path member has a flow path between a first member that absorbs laser light and a second member that transmits the laser light and visible light and that are stacked on top of each other, and is characterized by including a roughening process in which a first surface of the second member to which the first member is to be welded is roughened, and a welding process in which the first member and the first surface of the second member are brought into contact with each other and the area of ​​the first member that contacts the first surface is melted with the laser light, thereby welding the first member and the second member. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating the configuration of an inkjet printer including a liquid flow path member according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of an ink supply unit including a liquid flow path member. [Figure 3] FIG. 2 is a cross-sectional view showing the configuration of an ink branch flow path member as an example of a liquid flow path member. [Figure 4] FIG. 4 is a perspective cross-sectional view showing the AA cross section in FIG. 3. [Figure 5] FIG. 3 is a cross-sectional view showing the configuration of an ink collecting channel member. [Figure 6] FIG. 4 is a schematic cross-sectional view showing the configuration of a welded portion of the ink branch flow path member. [Figure 7] FIG. 4 is a flowchart showing a manufacturing process of the ink branch flow path member. [Figure 8] FIG. 1 is a schematic diagram showing an outline of a welding process. [Figure 9] Schematic diagram showing the state of reflected light in an inspection process. [Figure 10]Binarized images of welded and unwelded areas. [Figure 11] FIG. 10 is a schematic diagram showing the state of reflected light in a conventional inspection process according to a comparative example. [Figure 12] 10 is a binarized image of a welded portion and a non-welded portion according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the following embodiments, an inkjet printer, a liquid flow path member that is used as an ink branch flow path member in the inkjet printer, and a method for manufacturing the liquid flow path member are exemplified and will be described with reference to the drawings.

[0009] In the following figures, the Z axis is added along the vertical direction as necessary, the direction indicated by the arrow is the +Z direction, and the direction opposite to the + direction is the -Z direction. Also, in the following figures, the size of each component is made different from the actual size for the sake of convenience.

[0010] 1, the inkjet printer 1 includes a printing unit 10, a medium supply unit 20, a medium take-up unit 30, and a control unit 50. The inkjet printer 1 ejects and deposits liquid ink onto a continuous print medium 2, printing images such as text, patterns, pictures, and photographs onto the print medium 2.

[0011] The liquid flow path member according to this embodiment is applied to the ink supply unit 14 of the printing unit 10. In the following description, the inkjet printer 1 will also be simply referred to as the printer 1. The printer 1 is a so-called roll-to-roll type printer.

[0012] The control unit 50 comprehensively controls the operation of each component of the printer 1. The control unit 50 includes a CPU (Central Processing Unit), a system bus, ROM (Read Only Memory), RAM (Random Access Memory), etc. The CPU is responsible for the overall control of the printer 1. The CPU is electrically connected to the ROM, RAM, and each component of the printer 1 via the system bus. The ROM stores various control programs executed by the CPU, maintenance sequences, etc. The RAM temporarily stores data.

[0013] The printing unit 10 prints an image on the print medium 2 in accordance with a control signal from the control unit 50 based on image information to be printed. The printing unit 10 includes a discharge head 11, a transport roller 13, and an ink supply unit 14. The transport roller 13 pulls the print medium 2 from the medium supply unit 20 and sends it to the medium take-up unit 30.

[0014] As shown in FIG. 2, the ejection head 11 has a plurality of head units 11u. In the ejection head 11, the head units 11u are arranged in a manner corresponding to the width direction of the print medium 2. Each head unit 11u has a plurality of nozzles 111 arranged in a position that can face the print medium 2. Ink of each color, for example, black, cyan, yellow, and magenta, is ejected individually from the plurality of nozzles 111. Printing is performed by ejecting ink onto the print medium 2 from the nozzles of each head unit 11u at any timing while the print medium 2 is being transported.

[0015] The ink supply unit 14 circulates and supplies ink to each of the head units 11u. The ink supply unit 14 has an ink tank 61, an ink circulation path 63, and a pump 64. Note that Fig. 2 shows the configuration of one ink supply unit 14 corresponding to one head unit 11u. The printer 1 has at least the same number of ink tanks 61, ink circulation paths 63, pumps 64, etc. as the number of ink colors.

[0016] The ink circulation path 63 has an outgoing path 63a, a return path 63b, an ink branching path member 70, and an ink collecting path member 80. Although not shown, the ink circulation path 63 also includes tubes that form the ink path.

[0017] The outward path 63a is disposed between the ink tank 61 and the ink inlet port 112 of the ejection head 11. The return path 63b is disposed between the ink outlet port 113 of the ejection head 11 and the ink tank 61. The ink branching path member 70 and the ink collecting path member 80 are disposed within the ejection head 11, between the ink inlet port 112 and the ink outlet port 113.

[0018] The ink circulation path 63 circulates ink between the ink tank 61 and the ejection head 11 by driving a pump 64 provided in the outgoing path 63a. The ink tank 61 stores ink therein, sends the stored ink to the outgoing path 63a, and receives ink returned from the ejection head 11 through the returning path 63b.

[0019] The ink branching flow path member 70 divides and supplies ink supplied from the ink inlet 112 to each head unit 11u of the ejection head 11. The ink branching flow path member 70 is an example of a liquid flow path member of the present invention. The liquid flow path member of the present invention may also be applied to the ink collecting flow path member 80.

[0020] Returning to Figure 1, the medium supply unit 20 stores rolled printing medium 2 before printing and sends it out to the printing unit 10. In the transport path of the printing medium 2 from the medium supply unit 20 through the printing unit 10 to the medium winding unit 30, the direction along the transport path is defined as downstream, and the direction back along the transport path is defined as upstream. The medium supply unit 20 unwinds the printing medium 2 from the roll 21 and sends it downstream.

[0021] The medium take-up unit 30 takes up and stores the printed print medium 2 as a roll 31. The medium take-up unit 30 is disposed downstream of the printing unit .

[0022] The printer 1 is a so-called line head type printer. The printer to which the liquid flow path member of the present invention is applied is not limited to being a line head type. The liquid flow path member of the present invention may also be applied to a serial type printer. In a serial type printer, the ejection head is mounted on a carriage that moves along the width direction of the print medium 2, and printing is performed while the ejection head moves in conjunction with the movement of the carriage. The print medium 2 is not limited to being long, and may be a single sheet print medium such as A size, for example.

[0023] 3 and 4, the branch ink flow path member 70 includes a first member 71 and a second member 72. The first member 71 and the second member 72 are stacked on top of each other. The branch ink flow path member 70 also includes a welded portion (not shown). As will be described in detail later, the welded portion is a region where the first member 71 and the second member 72 are welded together.

[0024] 3 shows a configuration in which ink is divided into the six head units 11u by the ink branching flow path member 70. Also, FIG. 4 shows a state before the first member 71 and the second member 72 are welded together.

[0025] The first member 71 is a substantially rectangular parallelepiped substrate that extends in the ink flow path direction, specifically in the direction in which the head units 11u are arranged. A groove is formed in the center of the surface of the first member 71 that faces the second member 72, extending in the extension direction.

[0026] The second member 72 is laminated on the first member 71, covering the groove of the first member 71. A flow path 73 for flowing ink is formed between the second member 72 and the groove of the first member 71. Note that both ends of the groove of the first member 71 in the extension direction do not reach both ends of the first member 71. In other words, both ends of the flow path 73 in the extension direction are closed by the side walls of the first member 71, as shown in FIG.

[0027] The first member 71 is formed of a material that absorbs the laser light L1. The material used for the first member 71 is not particularly limited as long as it has the ability to absorb the laser light L1 and is not dissolved or swollen by the ink flowing through the flow path 73. Examples of such materials include thermoplastic resins such as polypropylene and polyamide that contain a black coloring material such as carbon black. Note that the coloring material contained in the first member 71 is not limited to being black, as long as it has the ability to absorb the laser light L1.

[0028] The property of the first member 71 to absorb the laser beam L1 is utilized in the welding process of the manufacturing process of the liquid flow path member, which will be described later. That is, when the first member 71 is irradiated with the laser beam L1, it absorbs the laser beam L1, generates heat, and melts. The heat generated by the first member 71 is propagated to the second member 72 that is in contact with the first member 71, melting the second member 72. As a result, the first member 71 and the second member 72 melt and mix at the interface where they contact. Then, when the irradiation of the laser beam L1 is stopped and the members are cooled, the interface solidifies and the members are joined. The region where the first member 71 and the second member 72 melt and mix becomes the welded portion.

[0029] The medium of the laser light L1 is not particularly limited, and for example, a known medium can be applied.

[0030] The second member 72 is formed of a material that transmits the laser light L1 and visible light. The material used for the second member 72 is not particularly limited as long as it is transparent to the laser light L1 and visible light and does not dissolve or swell with the ink flowing through the flow path 73. Examples of such materials include thermoplastic resins such as polyamide, polyethylene, polypropylene, polyethylene terephthalate, polystyrene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, acrylic resin, polycarbonate, and polybutylene terephthalate.

[0031] The property of the second member 72 to transmit the laser light L1 is utilized in the welding process and the inspection process after welding in the manufacturing process of the liquid flow path member. That is, the second member 72 is placed on top of the first member 71, and the laser light L1 is transmitted through the second member 72 and irradiated onto the first member 71 to heat the surface of the first member 71. In addition to the above, the property of the second member 72 to transmit visible light is also required for positioning during irradiation of the laser light L1 and for observing the welded portion in the inspection process.

[0032] Here, the first member 71 is not limited to absorbing 100% of the laser light L1, and the second member 72 is not limited to transmitting 100% of the laser light L1. The first member 71 and the second member 72 only need to have different transmittances for at least a certain wavelength of laser light L1, and the transmittance of the second member 72 must be higher than the transmittance of the first member 71. In other words, the absorption of the laser light L1 by the first member 71 and the transmittance of the laser light L1 by the second member 72 may each be less than 100%.

[0033] To manufacture the ink branching flow path member 70, the second member 72 is laminated on the first member 71, and laser light L1 is irradiated from the second member 72 side as shown in Fig. 4. Note that in Fig. 4, the first member 71 and the second member 72 are spaced apart to clarify the irradiation direction of the laser light L1 and the configurations of the first member 71 and the second member 72, but the laser light L1 is irradiated when the first member 71 and the second member 72 are in contact with each other.

[0034] 3, an ink passage port 711 and a plurality of ink passage ports 712 are provided in the groove that forms the flow path 73 in the first member 71. A sleeve 711s is attached to the ink passage port 711. A sleeve 712s is attached to each ink passage port 712.

[0035] More specifically, the ink passage port 711 and the sleeve 711s are disposed in one end region of the first member 71. The ink passage port 711 and the sleeve 711s communicate with the ink inlet port 112, and ink flowing in from the ink inlet port 112 flows into them.

[0036] The ink passage ports 712 and the sleeves 712s are arranged at approximately equal intervals between one end region and the other end region of the first member 71, corresponding to the arrangement of the head units 11u. Ink flows through each ink passage port 712 and each sleeve 712s to the corresponding head unit 11u. The ink branching flow path member 70 branches the ink from the ink tank 61 to each head unit 11u.

[0037] 5, the ink collection channel member 80 has a first substrate 81 and a second substrate 82. The ink collection channel member 80 is a channel member in the ejection head 11 that collects ink returning from each head unit 11u to the ink outlet port 113. The ink collection channel member 80 has a configuration similar to the ink branch channel member 70. When the liquid channel member of the present invention is applied to the ink collection channel member 80, the first substrate 81 is the first member, and the second substrate 82 is the second member.

[0038] The first substrate 81 and the second substrate 82 are laminated together. The second substrate 82 covers the grooves of the first substrate 81, forming flow paths 83. Ink flows through the flow paths 83. The flow paths 83 are closed by side walls of the first substrate 81 at both ends in the extension direction of the ink collection flow path member 80. The first substrate 81 is made of the same material as the first member 71, and the second substrate 82 is made of the same material as the second member 72.

[0039] In the first substrate 81, ink passing ports 812 and sleeves 812s are provided at approximately equal intervals corresponding to the multiple head units 11u in a range extending from one end region to the other end region. Ink returning from each head unit 11u passes through the ink passing ports 812 and the sleeves 812s. In the other end region of the first substrate 81, an ink passing port 811 and a sleeve 811s are provided. The ink passing port 811 and the sleeve 811s communicate with the ink outlet port 113, and ink returning to the ink outlet port 113 passes through the ink passing port 811 and the sleeve 811s.

[0040] Due to the configuration of the ink collecting flow path member 80 described above, the ink returning from each head unit 11u is collected at the ink outlet port 113 and merges.

[0041] As shown in Fig. 6, in the branch ink flow path member 70, the first member 71 and the second member 72 are stacked in the direction along the Z axis. The first member 71 is disposed in the -Z direction, and the second member 72 is disposed in the +Z direction. Note that the arrangement shown in Fig. 6 is an example of a certain local portion of the branch ink flow path member 70. The shapes and arrangements of the first member 71 and the second member 72 in the branch ink flow path member 70 are not limited to this.

[0042] The ink branching flow path member 70 has a flow path 73 and a welded portion 79. The flow path 73 is disposed between the first member 71 and the second member 72, that is, in a region where the first member 71 and the second member 72 are spaced apart in the direction along the Z axis, and a welded portion 79 is formed in the region where the first member 71 and the second member 72 contact each other, where the first member 71 and the second member 72 are welded together.

[0043] At the welded portion 79, the first member 71 and the second member 72 are laser welded together. Compared to other welding methods such as ultrasonic welding, vibration welding, high-frequency welding, and hot plate welding, laser welding can reduce damage to the first member 71 and the second member 72 and burrs that occur during processing. Note that the other welding methods mentioned above may also be used to weld the first member 71 and the second member 72 together.

[0044] In the second member 72, the surface facing the first member 71 in the direction along the Z axis, i.e., the surface facing the -Z direction, is defined as a first surface 72s1. The first surface 72s1 is the surface where the first member 71 is welded to the second member 72. In the second member 72, the surface opposite the first surface 72s1, i.e., the surface facing the +Z direction, is defined as a second surface 72s2.

[0045] The first surface 72s1 is roughened. The roughening of the first surface 72s1 is performed, for example, during the manufacturing stage of the second member 72. The roughening is performed to improve the accuracy of pass / fail determination in the inspection of the welded portion 79. The inspection of the welded portion 79 will be described in detail later.

[0046] The arithmetic mean roughness of the first surface 72s1 is larger than that of the second surface 72s2 of the second member 72. Specifically, it is preferable that the arithmetic mean roughness of the first surface 72s1 is 1.0 μm or more and 90.0 μm or less, and that the arithmetic mean roughness of the second surface 72s2 is 0.1 μm or less.

[0047] This increases the intensity of reflected light, which will be described later, on the first surface 72s1 of the first member 71, and makes it possible to further improve the accuracy of determining whether the welding of the welded portion 79 is good or bad.

[0048] The arithmetic mean roughness of the first surface 72s1 and the second surface 72s2 can be measured using a known method.

[0049] Next, a method for manufacturing a branch ink flow path member 70 will be described as an example of a method for manufacturing a liquid flow path member of the present invention. As shown in Fig. 7, the method for manufacturing the branch ink flow path member 70 according to this embodiment includes steps S1 to S5. Note that the method for manufacturing a liquid flow path member of the present invention is not limited to the following.

[0050] In step S1, the first member 71 and the second member 72 are formed separately. The method for forming the first member 71 and the second member 72 is not particularly limited, and known forming methods suitable for each configuration can be applied. In this embodiment, the first member 71 and the second member 72 are formed by injection molding.

[0051] In step S2, which is a surface roughening step, a surface roughening treatment is performed on the first surface 72s1 of the second member 72. In this embodiment, the surface roughening treatment in step S2 is performed in addition to the injection molding in step S1. Specifically, in the mold for molding the second member 72, the surface corresponding to the first surface 72s1 is roughened in advance. As a result, the roughened surface of the mold is transferred to the first surface 72s1.

[0052] Because the surface roughening treatment is performed when the second member 72 is formed, the number of steps can be reduced compared to when step S2 is performed after step S1. In the mold, the surfaces corresponding to the first surface 72s1 and the second surface 72s2 have the arithmetic mean roughnesses described above. In this embodiment, the arithmetic mean roughness of the first surface 72s1 is in the range of approximately 3.0 μm to approximately 12.0 μm.

[0053] Step S2 may be performed separately from step S1 without being combined with step S1. In this case, known methods such as various dry and wet etching methods can be applied to roughen the first surface 72s1. Then, the process proceeds to step S3.

[0054] In step S3, the first member 71 and the second member 72 are assembled together. At this time, the first member 71 and the second member 72 are brought into contact with each other in the areas that will become the welded portion 79. Then, the process proceeds to step S4.

[0055] In step S4, which is a welding step, the first member 71 and the second member 72 are welded together while the first member 71 and the first surface 72s1 of the second member 72 are in contact with each other. Specifically, as shown in Fig. 8, laser light L1 is irradiated in the -Z direction from the side of the second surface 72s2 of the second member 72. Then, the region of the first member 71 that is in contact with the first surface 72s1, i.e., the region corresponding to the welded portion 79, is melted by the laser light L1.

[0056] The laser light L1 passes through the second member 72 and reaches the dashed line region corresponding to the welded portion 79 of the first member 71. The first member 71 absorbs the laser light L1, generates heat, and melts. The heat generated by the first member 71 melts the second member 72. As a result, the first member 71 and the second member 72 melt and mix together in the dashed line region. At this time, the laser light L1 is irradiated onto the first member 71 while pressing the second member 72 in the -Z direction.

[0057] In this embodiment, an Nd:YAG (neodymium-doped yttrium aluminum garnet) laser with a central wavelength of 800 nm to 1100 nm is used as the laser light L1.

[0058] The laser light L1 only needs to be irradiated onto the broken line region that will become the welded portion 79, and may be irradiated locally using a mask or the like. Thereafter, by stopping the irradiation of the laser light L1, the first member 71 and the second member 72 are solidified to form the welded portion 79, completing the welding. Then, the process proceeds to step S5.

[0059] 7, in step S5, an inspection is performed to determine whether the weld is good or bad at the welded portion 79, which is the welded portion between the first member 71 and the second member 72. In this embodiment, an image of the welded portion 79 is captured via the second member 72 using an image sensor such as a CCD (Charge Coupled Device), and the captured image data is then binarized before being used to determine whether the weld is good or bad. This enables labor-saving inspection compared to visual inspection.

[0060] Here, as a comparative example, the state of the welded portion 79 at the time of imaging in a conventional branch ink flow path member 90 will be described. As shown in Fig. 11, the conventional branch ink flow path member 90 has a first member 71, a second member 72, and a welded portion 79, similar to the branch ink flow path member 70 of this embodiment.

[0061] The conventional branch ink flow path member 90 differs from the branch ink flow path member 70 in that the surface roughening treatment is omitted. In the following description, the same components of the branch ink flow path member 90 as those of the branch ink flow path member 70 are designated by the same numbers, and duplicated descriptions will be omitted.

[0062] In the branch ink flow path member 90, the surface facing the -Z direction and to which the first member 71 is welded is defined as a first surface 72s3. The first surface 72s3 is a surface that corresponds to the first surface 72s1 of the second member 72 of the branch ink flow path member 70.

[0063] The first surface 72s3 is not subjected to a roughening treatment. The arithmetic mean roughness of the first surface 72s3 is, for example, 0.1 μm or less, similar to that of the second surface 72s2, and specifically is approximately 0.1 μm.

[0064] In step S5, when capturing an image of the ink branching flow path member 90, inspection light L2 is irradiated in the −Z direction from the second surface 72s2 side of the second member 72. The inspection light L2 passes through the second member 72 and travels.

[0065] At the welded portion 79 , a part of the inspection light L 2 is reflected at the boundary between the welded portion 79 and the second member 72 to become reflected light W, and the other part of the inspection light L 2 is absorbed by the welded portion 79 and the first member 71 .

[0066] In the non-welded portion, which is an area other than the welded portion 79, part of the inspection light L2 is reflected at the interface between the second member 72 and the flow path 73, i.e., the first surface 72s3, to become reflected light R, and the other part of the inspection light L2 travels through the flow path 73. Then, part of the inspection light L2 that travels through the flow path 73 is reflected by the surface of the first member 71 facing the flow path 73, and the other part is absorbed by the first member 71. Although not shown in the figure, part of the inspection light L2 is also reflected by the second surface 72s2.

[0067] When the ink branching flow path member 90 is imaged from the +Z direction in the above-described state, the contrast of the image is R / W.

[0068] FIG. 12 shows a binarized image of the ink branching flow path member 90. In the binarized image, it is preferable that the welded portions 79 are displayed in black and the non-welded portions are displayed in white. However, as shown in FIG. 12, the boundary between the welded portions 79 and the non-welded portions in area A77 is unclear. This is due to the low contrast R / W of the captured image. With such a binarized image, it is difficult to accurately determine whether the welded portions 79 are good or bad, making it difficult to improve the accuracy of the determination. In contrast, the ink branching flow path member 70 of this embodiment roughens the first surface 72s1, thereby increasing the contrast of the captured image compared to conventional methods.

[0069] 9, in the branch ink flow path member 70, the first surface 72s1, which has been subjected to a surface roughening treatment, generates reflected light S from the inspection light L2. Specifically, the inspection light L2 is diffusely reflected by the first surface 72s1, which has many microscopic irregularities, and becomes reflected light S. Therefore, the reflected light S has a greater intensity than the conventional reflected light R described above. Furthermore, the reflected light W at the welded portion 79 in the branch ink flow path member 70 is substantially the same as that in the branch ink flow path member 90.

[0070] Therefore, the contrast of the captured image of the branching ink flow path member 70 is S / W, and the contrast S / W of the captured image of the branching ink flow path member 70 is greater than the contrast R / W of the captured image of the comparative example branching ink flow path member 90. Therefore, when the captured image of the branching ink flow path member 70 is binarized, the boundary between the welded portion 79 and the non-welded portion becomes clearer than before, as shown in FIG.

[0071] In this way, the ink branch flow path member 70 is manufactured.

[0072] According to this embodiment, the following effects can be obtained.

[0073] This can improve the accuracy of determining whether the welded portion 79 is good or bad in step S5. Specifically, in the welded portion 79, the first member 71 absorbs most of the inspection light L2 emitted during imaging. Meanwhile, in the non-welded areas, where the second member 72 is not in contact with the first member 71, the inspection light L2 is diffusely reflected by the roughened first surface 72s1 of the second member 72. Of the inspection light L2 reflected toward the imaging device, the intensity of the reflected light W from the welded portion 79 is relatively low, while the intensity of the reflected light S from the non-welded portion is relatively high. This makes it possible to clearly distinguish the boundary between the welded portion 79 and the non-welded portion when the captured image is binarized. This provides an ink branching flow path member 70 and a method for manufacturing the ink branching flow path member 70 that improve the accuracy of determining whether the welded portion 79 is good or bad.

[0074] The following describes the results derived from the embodiments.

[0075] The liquid flow path member comprises a first member, a second member laminated on the first member to form a flow path between the first member and the second member, and a welded portion where the first member and the second member are welded together, wherein the first member is formed from a material that absorbs laser light, and the second member is formed from a material that transmits laser light and visible light, and the first surface of the second member that faces the first member is subjected to a roughening treatment.

[0076] This configuration improves the accuracy of determining whether a welded portion is good or bad. Specifically, in the welded portion, the first member absorbs most of the inspection light during imaging. On the other hand, in the non-welded portion, which is an area other than the welded portion, the second member is not in contact with the first member, so the inspection light is diffusely reflected by the roughened first surface of the second member. Of the inspection light reflected toward the imaging device, the intensity of the light reflected from the welded portion is relatively low, and the intensity of the light reflected from the non-welded portion is relatively high. As a result, when the captured image is binarized, the boundary between the welded portion and the non-welded portion becomes clear. Therefore, a liquid flow path member can be provided that improves the accuracy of determining whether a welded portion is good or bad.

[0077] In the above-described liquid channel member, the arithmetic mean roughness of the first surface of the second member is greater than the arithmetic mean roughness of the second surface opposite to the first surface.

[0078] This configuration makes it easier for the inspection light to be diffusely reflected by the first surface of the second member, making the boundary between the welded portion and the unwelded portion clearer, thereby further improving the accuracy of determining whether the welded portion is good or bad.

[0079] In the above liquid channel member, the second member has an arithmetic mean roughness of the first surface of 1.0 μm or more and 90.0 μm or less, and an arithmetic mean roughness of the second surface of 0.1 μm or less.

[0080] This configuration makes it easier for the inspection light to be diffusely reflected by the first surface of the second member, making the boundary between the welded portion and the unwelded portion clearer, thereby further improving the accuracy of determining whether the welded portion is good or bad.

[0081] In the liquid flow path member, the first member and the second member are laser welded at the welded portion.

[0082] This configuration can reduce damage to the first and second members and burrs that occur during processing, compared to other welding methods such as ultrasonic welding, vibration welding, high-frequency welding, and hot plate welding.

[0083] The method for manufacturing a liquid flow path member has a flow path between a first member that absorbs laser light and a second member that transmits laser light and visible light and that are stacked on top of each other, and is characterized by including a roughening step in which a first surface of the second member to which the first member is welded is roughened, and a welding step in which the first member and the first surface of the second member are brought into contact with each other and the area of ​​the first member that contacts the first surface is melted with laser light to weld the first member and the second member.

[0084] This configuration improves the accuracy of determining whether a welded portion is good or bad. Specifically, in the welded portion, the first member absorbs most of the inspection light during imaging. On the other hand, in the non-welded portion, which is an area other than the welded portion, the second member is not in contact with the first member, so the inspection light is diffusely reflected by the roughened first surface of the second member. Of the inspection light reflected toward the imaging device, the intensity of the light reflected from the welded portion is relatively low, and the intensity of the light reflected from the non-welded portion is relatively high. As a result, when the captured image is binarized, the boundary between the welded portion and the non-welded portion becomes clear. Therefore, it is possible to provide a manufacturing method for a liquid flow path member that improves the accuracy of determining whether a welded portion is good or bad. [Explanation of symbols]

[0085] 70... ink branch flow path member as liquid flow path member, 71... first member, 72... second member, 72s1... first surface, 72s2... second surface, 73... flow path, 79... welded portion, L1... laser light, S2... step as roughening step, S4... step as welding step.

Claims

1. A first member; a second member laminated on the first member and forming a flow path between the second member and the first member; a welded portion at which the first member and the second member are welded, the first member is formed of a material that absorbs laser light, the second member is formed of a material that transmits the laser light and visible light, A liquid flow path member, wherein a first surface of the second member facing the first member is subjected to a surface roughening treatment.

2. The liquid channel member according to claim 1 , wherein the arithmetic mean roughness of the first surface of the second member is greater than the arithmetic mean roughness of a second surface opposite to the first surface.

3. In the second member, the arithmetic mean roughness of the first surface is 1.0 μm or more and 90.0 μm or less; The liquid channel member according to claim 2 , wherein the second surface has an arithmetic mean roughness of 0.1 μm or less.

4. The liquid channel member according to claim 1 , wherein the first member and the second member are laser welded to each other at the welded portion.

5. A method for manufacturing a liquid flow path member having a flow path between a first member that absorbs laser light and a second member that transmits the laser light and visible light, the first member being laminated to each other, the method comprising: a roughening step of roughening a first surface of the second member to which the first member is welded; a welding step of bringing the first member into contact with the first surface of the second member and melting the area of ​​the first member that comes into contact with the first surface with the laser light, thereby welding the first member to the second member.

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