Droplet discharge head and droplet discharge device

Abstract

This droplet discharge head comprises a flow path member and a reservoir. The flow path member has a plurality of discharge holes from which droplets are discharged. The reservoir is positioned above the flow path member and supplies liquid to the flow path member. The reservoir has a reservoir body containing a resin material. The reservoir body has a first groove part, a second groove part, and a connection part. The first groove part is located on the side opposite to the flow path member, and allows the liquid to flow therethrough. The second groove part is positioned on the flow path member side, and allows the liquid to flow therethrough. The connection part connects the first groove part and the second groove part. The first groove part and / or the second groove part has a curved portion that is curved so as not to overlap at least a portion of the other in plan view.

Description

Droplet ejection head and droplet ejection device

[0001] The disclosed embodiments relate to a droplet ejection head and a droplet ejection device.

[0002] Conventionally, droplet ejection heads that perform various types of printing by ejecting liquid onto a recording medium have been known as printing heads. Patent Document 1 discloses an inkjet head having a flat laminated flow path unit that has a reservoir that guides ink supplied from an ink supply port to an ink outlet.

[0003] Japanese Patent Application Laid-Open No. 2004-114404

[0004] The droplet ejection head of the present disclosure includes a flow path member and a reservoir. The flow path member has a plurality of ejection holes through which droplets are ejected. The reservoir is located on the flow path member and supplies liquid to the flow path member. The reservoir also has a reservoir body containing a resin material. The reservoir body has a first groove portion, a second groove portion, and a connection portion. The first groove portion is located on the opposite side from the flow path member and through which the liquid flows. The second groove portion is located on the flow path member side and through which the liquid flows. The connection portion connects the first groove portion and the second groove portion. Furthermore, at least one of the first groove portion and the second groove portion has a curved portion that is curved so as not to overlap with at least a portion of the other in a planar view.

[0005] FIG. 1 is a schematic side view of a printer according to an embodiment. FIG. 2 is a schematic plan view of a printer according to an embodiment. FIG. 3 is an exploded perspective view showing a schematic configuration of a droplet ejection head according to an embodiment. FIG. 4 is a perspective view showing an example of the configuration of a reservoir according to an embodiment. FIG. 5 is a top view showing an example of the configuration of a reservoir main body according to an embodiment. FIG. 6 is a bottom view showing an example of the configuration of a reservoir main body according to an embodiment. FIG. 7 is a diagram for explaining the function of a curved portion according to an embodiment. FIG. 8 is a cross-sectional perspective view showing an example of the configuration of a reservoir main body, an upper lid, and a pressing member according to an embodiment.

[0006] Hereinafter, a detailed description will be given of a droplet ejection head and a droplet ejection device according to the present disclosure (hereinafter referred to as an "embodiment") with reference to the drawings. Note that the present disclosure is not limited to the embodiment. Furthermore, the embodiments can be appropriately combined as long as the processing content is not contradictory. Furthermore, the same components in the following embodiments are designated by the same reference numerals, and redundant explanations will be omitted.

[0007] In addition, in the following embodiments, expressions such as "uniform," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "uniform," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis direction, Y-axis direction, and Z-axis direction, which are perpendicular to each other, are defined, and the positive Z-axis direction is the vertically upward direction.

[0009] Conventionally, droplet ejection heads that perform various types of printing by ejecting liquid onto a recording medium have been known as printing heads. Patent Document 1 discloses an inkjet head having a flat laminated flow path unit that has a reservoir that guides ink supplied from an ink supply port to an ink outlet.

[0010] However, when the reservoir made of metal in the above-mentioned conventional technology is changed to a resin material for the purpose of simplifying the manufacturing process, the thickness of the resin at the bottom of the flow path may become uneven, which may cause molding defects such as sink marks, which may result in a decrease in yield in the reservoir manufacturing process.

[0011] Therefore, there is a need for a technology that can solve the above problems and improve the yield in the reservoir manufacturing process.

[0012] <Configuration of Printer> First, an overview of a printer 1, which is an example of a droplet ejection device according to an embodiment, will be described with reference to Figures 1 and 2. Figure 1 is a schematic side view of the printer 1 according to an embodiment, and Figure 2 is a schematic plan view of the printer 1 according to an embodiment. The printer 1 according to an embodiment is, for example, a color inkjet printer.

[0013] As shown in FIG. 1, the printer 1 includes a paper feed roller 2, a guide roller 3, an applicator 4, a head case 5, a plurality of conveying rollers 6, a plurality of frames 7, a plurality of droplet ejection heads 8, a conveying roller 9, a dryer 10, a conveying roller 11, a sensor unit 12, and a recovery roller 13.

[0014] Furthermore, the printer 1 has a control unit 14 that controls the paper feed roller 2, guide roller 3, coater 4, head case 5, multiple conveying rollers 6, multiple frames 7, multiple droplet ejection heads 8, conveying roller 9, dryer 10, conveying roller 11, sensor unit 12, and recovery roller 13.

[0015] The printer 1 records images and characters on the printing paper P by causing droplets to land on the printing paper P. The printing paper P is an example of a recording medium. Before use, the printing paper P is wound around a paper feed roller 2. The printer 1 then transports the printing paper P from the paper feed roller 2, via a guide roller 3 and a coater 4, into the interior of a head case 5.

[0016] The coater 4 applies the coating agent evenly to the printing paper P. This allows the printing paper P to be surface treated, thereby improving the printing quality of the printer 1.

[0017] The head case 5 houses a plurality of transport rollers 6, a plurality of frames 7, and a plurality of droplet ejection heads 8. Inside the head case 5, a space is formed that is isolated from the outside, except for a portion that is connected to the outside, such as a portion where the printing paper P enters and leaves.

[0018] At least one of the control factors such as temperature, humidity, and air pressure of the internal space of the head case 5 is controlled by the control unit 14 as necessary. The transport rollers 6 transport the printing paper P inside the head case 5 to the vicinity of the droplet ejection heads 8.

[0019] The frame 7 is a rectangular flat plate, and is positioned above and in close proximity to the print paper P being transported by the transport rollers 6. As shown in Figure 2, the frame 7 is positioned so that its longitudinal direction is perpendicular to the transport direction of the print paper P. Inside the head case 5, multiple (for example, four) frames 7 are positioned along the transport direction of the print paper P.

[0020] In the following description, the transport direction of the printing paper P is also referred to as the "sub-scanning direction," and the direction perpendicular to the sub-scanning direction and parallel to the printing paper P is also referred to as the "main scanning direction."

[0021] A liquid, such as ink, is supplied from a liquid tank (not shown) to the droplet ejection head 8. In other words, ink is an example of a liquid. The droplet ejection head 8 ejects the liquid supplied from the liquid tank as droplets.

[0022] The control unit 14 controls the droplet ejection head 8 based on data such as images and characters, and ejects droplets toward the printing paper P. The distance between the droplet ejection head 8 and the printing paper P is, for example, about 0.5 to 20 mm.

[0023] The droplet ejection head 8 is fixed to the frame 7. For example, both ends in the longitudinal direction of the droplet ejection head 8 are fixed to the frame 7. The droplet ejection head 8 is positioned so that the longitudinal direction is perpendicular to the transport direction of the printing paper P.

[0024] That is, the printer 1 according to the embodiment is a so-called line printer in which the droplet ejection head 8 is fixed inside the printer 1. Note that the printer 1 according to the embodiment is not limited to a line printer, and may also be a so-called serial printer.

[0025] A serial printer is a printer that alternates between recording by moving the droplet ejection head 8 back and forth in a direction that intersects the transport direction of the printing paper P, for example, in a direction that is approximately perpendicular to the direction, and transporting the printing paper P.

[0026] As shown in Fig. 2, a plurality of (for example, five) droplet ejection heads 8 are fixed to one frame 7. Fig. 2 shows an example in which three droplet ejection heads 8 are positioned in front and two in the rear in the transport direction of the printing paper P, and the droplet ejection heads 8 are positioned in the transport direction of the printing paper P so that the centers of the droplet ejection heads 8 do not overlap.

[0027] A head group 8A is made up of multiple droplet ejection heads 8 positioned on one frame 7. The four head groups 8A are positioned along the transport direction of the printing paper P. The same color ink is supplied to droplet ejection heads 8 belonging to the same head group 8A. This allows the printer 1 to print with four colors of ink using the four head groups 8A.

[0028] The colors of ink ejected from each head group 8A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The control unit 14 controls each head group 8A to eject ink of multiple colors onto the printing paper P, thereby printing a color image on the printing paper P.

[0029] In order to treat the surface of the printing paper P, a coating agent may be ejected onto the printing paper P from the droplet ejection head 8 .

[0030] Furthermore, the number of droplet ejection heads 8 included in one head group 8A and the number of head groups 8A mounted on the printer 1 can be changed as appropriate depending on the object to be printed and the printing conditions. For example, if a single color is printed on the printing paper P and the printing area is to be printed with one droplet ejection head 8, the number of droplet ejection heads 8 mounted on the printer 1 may be one.

[0031] The printing paper P that has been printed inside the head case 5 is transported to the outside of the head case 5 by transport rollers 9 and passes through the inside of a dryer 10. The dryer 10 dries the printing paper P that has been printed. The printing paper P that has been dried in the dryer 10 is transported by transport rollers 11 and collected by a collection roller 13.

[0032] In the printer 1, by drying the printing paper P in the dryer 10, it is possible to reduce adhesion between overlapping printing paper P wound up on the recovery roller 13 and rubbing of undried liquid.

[0033] The sensor unit 12 is composed of a position sensor, a speed sensor, a temperature sensor, etc. The control unit 14 can determine the state of each part of the printer 1 based on information from the sensor unit 12 and control each part of the printer 1.

[0034] The printer 1 described so far uses printing paper P as the printing object (i.e., recording medium), but the printing object of the printer 1 is not limited to printing paper P. For example, the printing object may be a roll of cloth or the like.

[0035] Furthermore, the printer 1 may transport the printing paper P on a conveyor belt instead of directly transporting the printing paper P. By using a conveyor belt, the printer 1 can print on sheets of paper, cut pieces of cloth, wood, tiles, and the like.

[0036] The printer 1 may also print wiring patterns for electronic devices by discharging droplets containing conductive particles from the droplet discharging head 8. The printer 1 may also produce chemicals by discharging a predetermined amount of liquid chemicals or droplets containing chemicals from the droplet discharging head 8 toward a reaction vessel or the like.

[0037] The printer 1 may also include a cleaning unit that cleans the droplet ejection head 8. The cleaning unit cleans the droplet ejection head 8 by, for example, wiping or capping.

[0038] The wiping process is a process of removing liquid adhering to the droplet ejection head 8 by wiping the surface of the area where droplets are ejected with a flexible wiper, for example.

[0039] The capping process is performed, for example, as follows: First, a cap is placed over the surface of the portion onto which droplets are to be ejected (this process is called capping). As a result, a nearly sealed space is formed between the surface onto which droplets are to be ejected and the cap.

[0040] Next, droplets are repeatedly ejected in this sealed space, which removes any liquid with a higher viscosity than normal or foreign matter that may have clogged the ejection holes (nozzles) that eject droplets.

[0041] <Configuration of droplet ejection head> Next, the configuration of the droplet ejection head 8 according to the embodiment will be described with reference to Fig. 3. Fig. 3 is an exploded perspective view showing the schematic configuration of the droplet ejection head 8 according to the embodiment.

[0042] 3, the droplet ejection head 8 includes a head body 20, a wiring section 30, a head cover 40, and two heat sinks 45. The head body 20 includes a flow path member 21, a piezoelectric actuator substrate (not shown), a branch flow path member 23, and a reservoir 24.

[0043] In the following description, for convenience, the direction in which the head body 20 is provided in the droplet ejection head 8 may be referred to as "downward," and the direction in which the head cover 40 is provided relative to the head body 20 may be referred to as "upward."

[0044] The flow path member 21 of the head main body 20 has a generally flat plate shape and has a first surface, which is one main surface, located on the branch flow path member 23 side (the Z-axis positive side in the figure), and a second surface located on the opposite side of the first surface (the Z-axis negative side in the figure). The first surface has openings (not shown), and liquid is supplied from the reservoir 24 to the inside of the flow path member 21 through these openings. Two openings through which liquid is supplied are located at each end of the flow path member 21 in the longitudinal direction. The two openings at each end are arranged side by side along the short side.

[0045] The second surface has a plurality of ejection holes (not shown) that eject droplets onto the printing paper P. The flow path member 21 has therein a flow path that allows the liquid to flow from the first surface to the second surface.

[0046] The flow path member 21 includes a piezoelectric actuator substrate, which is located on a first surface of the flow path member 21. The piezoelectric actuator substrate has a plurality of displacement elements (not shown). A flexible substrate 31 of the wiring section 30 is electrically connected to the piezoelectric actuator substrate.

[0047] The branch flow path member 23, which is a connecting flow path member, is located on the flow path member 21. The branch flow path member 23 has a branch flow path (not shown) therein, which is a connecting flow path connected to the flow path of the flow path member 21.

[0048] The branch flow path member 23 may be a box-shaped member that extends long in the main scanning direction (Y-axis direction) and has an open top. By making the branch flow path member 23 box-shaped, the rigidity of the branch flow path member 23 can be increased compared to when the branch flow path member 23 is flat. This can reduce the amount of deflection of the nozzle surface of the flow path member 21 joined to the branch flow path member 23.

[0049] The reservoir 24 is located on the branch flow path member 23. The reservoir 24 has openings 24a at both ends in the main scanning direction (the Y-axis direction in the figure). The reservoir 24 has a flow path therein, and liquid is supplied from the outside through the openings 24a. The reservoir 24 supplies liquid to the flow path member 21. The reservoir 24 also stores the liquid supplied to the flow path member 21. The detailed configuration of the reservoir 24 will be described later.

[0050] The reservoir 24 may further include a heater substrate (not shown) and a heating resistor (not shown). The heater substrate brings the liquid flowing through the head body 20 closer to a predetermined temperature. The reservoir 24 has holes 24b formed on the side surface facing the heat sink 45 to accommodate fixing members (not shown), such as screws or bolts.

[0051] The wiring section 30 has a flexible substrate 31, a wiring substrate 32, a plurality of driver ICs 33, and a pressing member 34. The flexible substrate 31 is a flexible wiring substrate, and transmits a predetermined signal sent from the outside to the head main body 20. As shown in Fig. 3, the droplet ejection head 8 according to the embodiment has two flexible substrates 31.

[0052] One end of the flexible substrate 31 is electrically connected to the piezoelectric actuator substrate of the flow path member 21 in the head main body 20. The other end of the flexible substrate 31 is drawn out above the reservoir 24 and is electrically connected to the wiring substrate 32. This allows the piezoelectric actuator substrate of the flow path member 21 in the head main body 20 to be electrically connected to the outside.

[0053] The wiring board 32 is located above the head body 20. The wiring board 32 distributes signals to a plurality of driver ICs 33.

[0054] The plurality of driver ICs 33 are located on one main surface of the flexible substrate 31. As shown in Fig. 3, in the droplet ejection head 8 according to the embodiment, two driver ICs 33 are provided on each flexible substrate 31. Note that the number of driver ICs 33 provided on each flexible substrate 31 is not limited to two.

[0055] The driver IC 33 drives each displacement element on the piezoelectric actuator substrate of the head main body 20 based on a drive signal sent from the control unit 14 (see FIG. 1 ). In this way, the driver IC 33 drives the droplet ejection head 8.

[0056] The pressing member 34 is, for example, a leaf spring having a substantially U-shaped cross section. The pressing member 34 is located between the two flexible substrates 31 and presses the driver IC 33 on the flexible substrate 31 toward the heat sink 45. This brings the driver IC 33 into close contact with the heat sink 45, allowing heat generated when the driver IC 33 is driven to be efficiently dissipated to the heat sink 45.

[0057] The pressing force does not have to be generated directly by the pressing member 34. For example, a force generated by another member may press the driver IC 33 via the pressing member 34.

[0058] The head cover 40 is attached to the head body 20 and is arranged so as to cover the wiring section 30, such as the flexible substrate 31, the wiring substrate 32, and the pressing member 34, located on the head body 20. This allows the head cover 40 to seal the wiring section 30. The head cover 40 is made of, for example, resin or metal.

[0059] The head cover 40 has a box shape that extends elongatedly in the main scanning direction, and has a first opening 40a and a second opening 40b on two side surfaces that face each other in the sub-scanning direction (the X-axis direction in the figure). In the example of Fig. 3, the first opening 40a is provided on the side surface located on the positive side of the X axis, and the second opening 40b is provided on the side surface located on the negative side of the X axis. The head cover 40 also has a third opening 40c on its bottom surface and a fourth opening 40d on its top surface.

[0060] The two heat sinks 45 are attached to the head cover 40. One of the two heat sinks 45 is disposed so as to cover the first opening 40a, and the other is disposed so as to cover the second opening 40b.

[0061] The heat sink 45 is, for example, a plate-shaped member that is long in the longitudinal direction of the droplet ejection head 8, and is made of a metal or alloy with high heat dissipation properties. The heat sink 45 is provided so as to be in contact with the driver IC 33, and dissipates heat generated by the driver IC 33.

[0062] Each of the two heat sinks 45 has a plurality of through holes 46 for accommodating fixing members, and the head cover 40 has a plurality of through holes 41 for accommodating such fixing members.

[0063] The two heat sinks 45 are each fixed to the head cover 40 by a fixing member. The head cover 40 to which the heat sinks 45 are attached has a box shape in which the first opening 40a and the second opening 40b are closed and the third opening 40c and the fourth opening 40d are open.

[0064] The third opening 40c is positioned to face the reservoir 24. The flexible substrate 31 and the pressing member 34 are inserted through the third opening 40c.

[0065] The fourth opening 40d is provided for inserting a connector (not shown) provided on the wiring board 32. If the space between the connector and the fourth opening 40d is sealed with resin or the like, it becomes difficult for liquid or dust to enter the inside of the head cover 40.

[0066] The head cover 40 may also have a heat insulating portion (not shown) between the heat sink 45 and the head body 20. By providing the head cover 40 with a heat insulating portion, heat generated by the driver IC 33 is less likely to be transmitted to the head body 20 via the heat sink 45.

[0067] 3 shows an example of the configuration of the droplet ejection head 8, and the droplet ejection head 8 may further include members other than those shown in FIG.

[0068] <Configuration of Reservoir> Next, a detailed configuration of the reservoir 24 according to the embodiment will be described with reference to Fig. 4 to Fig. 8. Fig. 4 is a perspective view showing an example of the configuration of the reservoir 24 according to the embodiment.

[0069] As shown in Fig. 4, the reservoir 24 is a box-shaped member that extends long in the main scanning direction (Y-axis direction). An ink supply pipe 24c, through which ink is supplied from outside, is located on the top surface (the surface on the positive Z-axis direction side) of the reservoir 24. The ink supply pipe 24c is connected to the opening 24a shown in Fig. 3, and a pair of ink supply pipes 24c is provided at both ends of the reservoir 24 in the main scanning direction.

[0070] Furthermore, an ink outlet 24d is located on the lower surface (surface on the negative Z-axis direction side) of the reservoir 24, and leads the ink that has flowed inside the reservoir 24 to the branch flow path member 23 (see FIG. 3). A pair of such ink outlets 24d is provided on both ends of the reservoir 24 in the main scanning direction.

[0071] The reservoir 24 includes a reservoir body 101, an upper cover 102, and a lower cover 103. The reservoir body 101 includes a resin material. The reservoir body 101 is formed, for example, as a single unit. The reservoir body 101 is formed, for example, by injection molding.

[0072] The top cover 102 is positioned to cover the first surface 101a (see FIG. 5) of the reservoir body 101. The first surface 101a is the surface of the reservoir body 101 that is located on the opposite side (i.e., the positive Z-axis direction side) from the flow path member 21 (see FIG. 3). The top cover 102 has, for example, the pair of ink supply tubes 24c described above and is made of, for example, resin.

[0073] The lower lid 103 is positioned to cover the second surface 101b (see FIG. 6) of the reservoir body 101. The second surface 101b is the surface of the reservoir body 101 that faces the flow path member 21 (i.e., the negative Z-axis direction side). The lower lid 103 has, for example, the pair of ink outlet ports 24d described above and is made of, for example, resin.

[0074] Fig. 5 is a top view showing an example of the configuration of the reservoir body 101 according to the embodiment. As shown in Fig. 5, a pair of first groove portions 110 are located on a first surface 101a of the reservoir body 101, i.e., on the side of the reservoir body 101 opposite to the flow path member 21 (see Fig. 3). The first groove portions 110 have a groove shape, and when the top cover 102 (see Fig. 4) covers the first surface 101a, they form first flow paths 104 (see Fig. 8) through which ink flows.

[0075] The first groove portion 110 has, in order from the upstream side (the ink supply tube 24c (see FIG. 4) side), a curved portion 111, a tapered portion 112, and a widened portion 113. The curved portion 111 is an example of a bent portion.

[0076] The curved portion 111 is connected to the ink supply tube 24c and is a narrow portion that extends from a connection portion 111a with the ink supply tube 24c toward the center in the longitudinal direction (Y-axis direction) of the reservoir body 101. The curved portion 111 is also bent in the longitudinal direction.

[0077] The tapered portion 112 is connected to the downstream side of the curved portion 111 and has a width that gradually increases toward the center in the longitudinal direction. The widened portion 113 is connected to the downstream side of the tapered portion 112 and has a substantially uniform width that is wider than the curved portion 111.

[0078] In the first groove portion 110, which becomes the first flow path 104 when covered by the upper cover 102, the ink supplied from the ink supply tube 24c flows as a flow L1 toward the center of the reservoir body 101 in the longitudinal direction.

[0079] Then, the ink that reaches the center of the reservoir 24 from both ends in the first flow path 104 flows through the connection portion 130 formed in the center of the reservoir body 101 and flows into the second flow path 105 (see Figure 8) provided on the second surface 101b (see Figure 6) side of the reservoir 24.

[0080] The connecting portion 130 is provided to penetrate between the first flow path 104 (first groove portion 110) and the second flow path 105 (second groove portion 120) in the vertical direction (Z-axis direction). The connecting portion 130 is a flow path that connects the first groove portion 110 and the second groove portion 120 in a state where a fluid can flow between them.

[0081] Fig. 6 is a bottom view showing an example of the configuration of the reservoir body 101 according to the embodiment. As shown in Fig. 6, a second groove portion 120 is located on the second surface 101b of the reservoir body 101, i.e., on the flow path member 21 (see Fig. 3) side of the reservoir body 101. The second groove portion 120 has a groove shape, and when the lower cover 103 (see Fig. 4) covers the second surface 101b, it becomes a second flow path 105 (see Fig. 8) through which ink flows.

[0082] The second groove portion 120 has a substantially uniform width from the upstream side connected to the connection portion 130 to the downstream side connection portion 120a connected to the ink outlet 24d (see Figure 4), and extends substantially parallel to the longitudinal direction (Y-axis direction).

[0083] In the second groove portion 120, which becomes the second flow path 105 when covered with the lower cover 103, the ink supplied from the connection portion 130 flows as a flow L2 toward both ends in the longitudinal direction of the reservoir body 101. Then, the ink that reaches the connection portion 120a is led out of the reservoir 24 to the branch flow path member 23 (see FIG. 3) via the ink lead-out port 24d.

[0084] Ink is supplied from ink outlets 24d at both longitudinal ends of branch flow path member 23. The ink introduced into branch flow path member 23 is split into two in the short direction by branch flow paths within branch flow path member 23 at both longitudinal ends, and is supplied to four openings in flow path member 21.

[0085] The branch flow path in the branch flow path member 23 need only be a connecting flow path that connects the reservoir 24 and the flow path member 21, and does not have to branch along the way. Alternatively, the ink outlet 24d may be directly connected to the opening of the flow path member 21 without providing the branch flow path member 23.

[0086] As described above, the reservoir 24 according to this embodiment has one ink supply tube 24c located at each of its longitudinal ends, and the reservoir 24 has a structure that allows ink to be supplied into the reservoir 24 from both of the two ink supply tubes 24c.

[0087] As a result, by initially supplying ink from only one of the ink supply pipes 24c, it is possible to easily remove any air remaining inside the other ink supply pipe 24c and any liquid that was previously inside the other ink supply pipe 24c that is different from the ink being supplied. When actually printing, ink may be supplied from only one ink supply pipe 24c, or from two ink supply pipes 24c.

[0088] Furthermore, even during printing, ink may be supplied from one ink supply pipe 24c, and the ink in the reservoir 24 (first flow path 104) may be recovered to the outside using the other ink supply pipe 24c. The recovered liquid may be supplied again from one ink supply pipe 24c, for example, through a filter (not shown). In other words, in the droplet ejection head 8 according to the embodiment, ink may be circulated.

[0089] Furthermore, the reservoir 24 according to the embodiment has a structure in which ink supplied from each of the pair of first flow paths 104 joins at the connection portion 130 and then branches again from the connection portion 130 into a pair of second flow paths 105.

[0090] This allows the ink to be drawn out from the pair of ink outlet ports 24d located at both ends into the branch flow path member 23 in the same ink drawing state at both ink outlet ports 24d.

[0091] Here, in the embodiment, as described above, at least one of the first groove portion 110 and the second groove portion 120 has a curved portion (for example, curved portion 111) that is curved so as not to overlap at least a portion of the other groove portion in a planar view.

[0092] For example, in the present disclosure, the first groove portion 110 has a curved portion 111 that is curved so as not to overlap, in plan view, with at least a portion of the second groove portion 120. Note that the first groove portion 110 and the second groove portion 120 do not necessarily have to overlap at all in plan view.

[0093] The curved portion 111 may be provided in both the first groove portion 110 and the second groove portion 120, but since it is generally preferable for the flow path to be linear, it is preferable to provide the curved portion 111 in either one of them. Note that in this disclosure, the term "plan view" refers to a viewpoint when viewed from a direction perpendicular to the first surface 101 a or the second surface 101 b.

[0094] FIG. 7 is a diagram for explaining the function of the bending portion 111 according to the embodiment, and is a cross-sectional perspective view corresponding to the cross section taken along the line AA in FIG.

[0095] As shown in Figure 7, in the embodiment, the first groove portion 110 formed on the first surface 101a of the reservoir body 101 has a curved portion 111, making it possible to form a recess 115 at a position on the first surface 101a that overlaps with the second groove portion 120 in a planar view.

[0096] This makes it possible to set the thickness T of the bottom of the second groove portion 120 to a desired value by controlling the depth of the recess 115. Therefore, in the embodiment, the thickness T of the bottom of the first groove portion 110 and the thickness T of the bottom of the second groove portion 120 can be made substantially equal.

[0097] Therefore, according to the embodiment, when molding the reservoir body 101 containing a resin material, the occurrence of molding defects such as sink marks can be reduced, thereby improving the yield in the manufacturing process of the reservoir 24.

[0098] In the embodiment, in the portion of the second groove portion 120 that overlaps with the tapered portion 112 in a planar view, the thickness of the bottom can be made approximately equal to that of other portions by removing material from the side of the reservoir body 101.

[0099] In addition, in the embodiment, in the portion of the second groove portion 120 that overlaps with the widened portion 113 in a planar view, the groove depth of the widened portion 113 is increased and the thickness is removed, so that the thickness of the bottom portion can be made approximately equal to that of other portions.

[0100] The second flow path 105 may have a symmetrical structure in the short side direction and may be short in length in order to stably supply ink to the flow path member 21. That is, the second flow path 105 may be linear and disposed in the center in the short side direction. In order to form the second flow path 105 in such a shape, the curved portion 111 may be provided in the first groove portion 110 that becomes the first flow path 104, rather than in the second groove portion 120 that becomes the second flow path 105.

[0101] The connection part 130 may be disposed at the center in the longitudinal direction and the center in the lateral direction of the reservoir body 101. Furthermore, the second flow path 105 may extend from the connection part 130 toward both ends.

[0102] This allows the second flow path 105 to supply ink evenly and stably to the openings at both longitudinal ends of the flow path member 21. To supply ink more evenly and stably, the second flow path 105 may have a structure that is symmetrical in the longitudinal and lateral directions.

[0103] In addition, in the embodiment, the reservoir body 101 may have a fitting portion located near the curved portion 111 for positioning a separate member. Such a fitting portion may be, for example, a protrusion 114 or a recess. If the protrusion 114 is provided, the shape of the fitting object does not need to be complex. For example, a flat member with a hole or the like can be fitted into the protrusion 114.

[0104] 8 is a cross-sectional perspective view showing an example of the configuration of the reservoir body 101, the upper cover 102, and the pressing member 34 according to the embodiment. As shown in Fig. 8, in the embodiment, the reservoir body 101 has the protrusion 114, which makes it possible to easily position other members adjacent to the first surface 101a where the protrusion 114 is located.

[0105] 8, for example, through holes are formed in the top cover 102 that directly contacts the first surface 101a of the reservoir body 101, and in the pressing member 34 that contacts the upper surface of the top cover 102. As a result, by inserting the protrusion 114 into the through holes, the top cover 102 and the pressing member 34 can be easily positioned.

[0106] Therefore, according to the embodiment, the manufacturing cost of the droplet ejection head 8 can be reduced.

[0107] 5, the protrusion 114 may be located at the center of the reservoir body 101 in the short direction (X-axis direction), thereby improving the positioning stability of other components positioned by the protrusion 114.

[0108] In this disclosure, "located in the center in the short direction" means that the center of the protrusion 114 is located in the central 1 / 3 range in the short direction of the reservoir body 101, further located in the central 1 / 5 range, and particularly located essentially in the center.

[0109] In addition, in the embodiment, the first groove portion 110 may have one curved portion 111 at each end in the longitudinal direction (Y-axis direction), thereby improving the molding accuracy around the second groove portion 120 at both ends of the reservoir body 101.

[0110] Furthermore, the protrusions 114 may be located near the two curved portions 111, respectively, and the line connecting the two protrusions 114 may be parallel to the longitudinal direction. This can further improve the positioning stability of other members that are positioned by the protrusions 114.

[0111] Here, the position of the protrusion 114 may be within the range in which the curved portion 111 exists in the longitudinal direction of the flow path member 21. Furthermore, the distance between the protrusion 114 and the curved portion 111 in the lateral direction of the flow path member 21 may be ½ or less, or even ¼ or less, of the lateral direction of the flow path member 21.

[0112] In addition, in the embodiment, as described above, the positioning of the top cover 102 may be performed by the protrusion 114 provided on the reservoir body 101. The positioning of the pressing member 34 may also be performed by the protrusion 114. This allows the positioning accuracy of the top cover 102 and the pressing member 34 to be increased.

[0113] Furthermore, in the above-described positioning, the upper cover 102 and the pressing member 34 may be positioned with respect to the same protrusion 114. This improves the positional accuracy between the upper cover 102 and the pressing member 34, thereby minimizing the cumulative tolerance of multiple members assembled on the reservoir body 101.

[0114] 5 , in the embodiment, the filter member 140 may be positioned in the widened portion 113 of the first groove portion 110 so as to cover the opening of the connection portion 130. This allows all of the ink flowing inside the reservoir 24 to be filtered by a single filter member 140.

[0115] The filter member 140 may be arranged so as to cover the opening of the connection part 130 on the first flow path 104 side from the first flow path 104 side. By arranging it in this manner, it is possible to prevent the filter member 140 from separating from the opening of the connection part 130.

[0116] In addition, in the embodiment, by placing the filter member 140 in the widened portion 113, which is formed deeper than other parts to remove weight from the bottom, the space inside the reservoir 24 can be effectively utilized.

[0117] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0118] For example, in the above embodiment, an example has been shown in which the curved portion 111 is provided in the first groove portion 110 located on the first surface 101 a of the reservoir body 101. However, the present disclosure is not limited to such an example, and a curved portion may be provided in the second groove portion 120 located on the second surface 101 b, or curved portions may be provided in both the first groove portion 110 and the second groove portion 120.

[0119] This also allows the thickness of the bottom of the first groove 110 and the second groove 120 to be set to a desired value, thereby improving the yield in the manufacturing process of the reservoir 24.

[0120] Furthermore, in the above embodiment, as long as the first groove portion 110 and the second groove portion 120 do not overlap in a planar view, it is not necessary for both the first groove portion 110 and the second groove portion 120 to have a curved portion.

[0121] This also allows the thickness of the bottom of the first groove 110 and the second groove 120 to be set to a desired value, thereby improving the yield in the manufacturing process of the reservoir 24.

[0122] In addition, in the present disclosure, when a curved portion is provided in the second groove portion 120 of the second surface 101b, a protrusion may be provided near the curved portion, which makes it possible to easily position other members (such as the lower cover 103) adjacent to the second surface 101b of the reservoir body 101.

[0123] The embodiments also describe a mode in which ink is supplied from the outside to the reservoir 24 during printing, and a mode in which ink is supplied from the outside to the reservoir 24 and ink is recovered from the reservoir 24 to the outside. In the latter mode, ink may be supplied from the reservoir 24 to the flow path member 21 and ink may be recovered from the flow path member 21 to the reservoir 24.

[0124] Furthermore, ink may be supplied to and recovered from the flow paths facing the nozzles (ejection holes) within the flow path member 21, thereby preventing ink from accumulating within the nozzles and their surroundings. In such an embodiment, ink is supplied from the outside to the droplet ejection head 8 as a whole, some of the ink is ejected, and the ink that is not ejected is recovered to the outside.

[0125] The ink recovered to the outside may be supplied again to the droplet ejection head 8. In other words, the ink may be circulated. The supply and recovery of ink to the droplet ejection head 8, or the circulation of ink, may be controlled by the control unit 14.

[0126] Further advantages and other aspects may readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0127] The present technology can also be configured as follows. (1) A droplet ejection head comprising: a flow path member having a plurality of ejection holes through which droplets are ejected; and a reservoir located on the flow path member and supplying liquid to the flow path member, wherein the reservoir has a reservoir body containing a resin material, the reservoir body having a first groove portion located on the opposite side from the flow path member and through which the liquid flows, a second groove portion located on the flow path member side and through which the liquid flows, and a connecting portion connecting the first groove portion and the second groove portion, wherein at least one of the first groove portion and the second groove portion has a curved portion that is curved so as not to overlap with at least a portion of the other groove portion in a planar view. (2) The droplet ejection head described in (1), wherein the first groove portion has the curved portion. (3) The droplet ejection head described in (2), wherein the first groove portion has one curved portion at each of both ends in the longitudinal direction along which the second groove portion extends. (4) The droplet ejection head according to any one of (1) to (3), wherein the reservoir body has a fitting portion located near the curved portion and for positioning a separate member. (5) The droplet ejection head according to (4), wherein the reservoir body has a longitudinal direction in which the second groove portion extends and a lateral direction perpendicular to the longitudinal direction in a plan view, and the fitting portion is located at a center of the reservoir body in the lateral direction. (6) The droplet ejection head according to (5), wherein the first groove portion has one curved portion at each end in the longitudinal direction, and the fitting portion is located near one of the curved portions at each end in the longitudinal direction, and a line connecting the two fitting portions is parallel to the longitudinal direction. (7) The droplet ejection head according to any one of (4) to (6), wherein the reservoir further has an upper lid covering the reservoir body on the opposite side from the flow path member, and the position of the upper lid relative to the reservoir body is determined by the fitting portion. (8) The droplet ejection head according to any one of (4) to (7), further comprising: a flexible substrate electrically connected to the flow path member, a heat sink, and a pressing member that presses the flexible substrate against the heat sink, and the position of the pressing member relative to the reservoir body is determined by the fitting portion.(9) The droplet ejection head according to (7), further comprising: a flexible substrate electrically connected to the flow path member; a heat sink; and a pressing member that presses the flexible substrate toward the heat sink, wherein the positions of the upper cover and the pressing member relative to the reservoir body are determined by the same fitting portion. (10) The droplet ejection head according to any one of (1) to (9), wherein the reservoir has a filter member positioned so as to cover the opening of the connection portion. (11) A droplet ejection device comprising: the droplet ejection head according to any one of (1) to (10); and a control unit that controls the droplet ejection head.

[0128] REFERENCE SIGNS LIST 1 Printer (an example of a droplet ejection device) 8 Droplet ejection head 14 Control unit 21 Flow path member 24 Reservoir 31 Flexible substrate 45 Heat sink 101 Reservoir body 101a First surface 101b Second surface 102 Upper cover 103 Lower cover 104 First flow path 105 Second flow path 110 First groove 111 Curved portion (an example of a curved portion) 114 Protrusion (an example of a fitting portion) 120 Second groove 130 Connection portion 140 Filter member

Claims

1. A flow channel member having multiple discharge holes from which droplets are discharged, A reservoir located above the flow channel member and supplying liquid to the flow channel member, Equipped with, The reservoir has a reservoir body containing a resin material, The reservoir body has a first groove located on the opposite side of the flow channel member through which the liquid flows, a second groove located on the side of the flow channel member through which the liquid flows, and a connecting portion connecting the first groove and the second groove. At least one of the first groove and the second groove has a curved portion that, within the range in which both are arranged in the longitudinal direction, does not overlap with at least a part of the other in a plan view. Droplet dispensing head.

2. A flow channel member having a plurality of discharge holes from which droplets are discharged, A reservoir located above the flow channel member and supplying liquid to the flow channel member, Equipped with, The reservoir has a reservoir body containing a resin material, The reservoir body has a first groove located on the opposite side of the flow channel member through which the liquid flows, a second groove located on the side of the flow channel member through which the liquid flows, and a connecting portion connecting the first groove and the second groove. Both the longitudinal ends of the first groove and the second groove are located in the central part in the short direction. The first groove has a curved portion in a plan view in the region excluding the two ends. Droplet dispensing head.

3. The first groove has the curved portion The droplet dispensing head according to claim 1.

4. The first groove has one curved portion at each end in the longitudinal direction in which the second groove extends. The droplet dispensing head according to claim 2 or 3.

5. The reservoir body is located near the curved portion and has a fitting portion for positioning another component. A droplet dispensing head according to any one of claims 1 to 3.

6. The reservoir body has a longitudinal direction in which the second groove extends and a short direction perpendicular to the longitudinal direction in a plan view. The fitting portion is located in the central part of the reservoir body in the short direction. The droplet dispensing head according to claim 5.

7. The first groove has one curved portion at each of its ends in the longitudinal direction, The fitting portion is located near one of the curved portions at each end in the longitudinal direction, The line connecting the two aforementioned fitting portions is parallel to the longitudinal direction. The droplet dispensing head according to claim 6.

8. The reservoir further has an upper cover that covers the reservoir body on the side opposite to the flow path member, The position of the upper cover relative to the reservoir body is determined by the fitting portion. The droplet dispensing head according to claim 5.

9. A flexible substrate electrically connected to the aforementioned flow channel member, Heat sink and A pressing member for pressing the flexible substrate toward the heat sink, Furthermore, The position of the pressing member relative to the reservoir body is determined by the fitting portion. The droplet dispensing head according to claim 5.

10. A flexible substrate electrically connected to the aforementioned flow channel member, Heat sink and A pressing member for pressing the flexible substrate toward the heat sink, Furthermore, The upper cover and the pressing member are positioned relative to the reservoir body by the same fitting portion. The droplet dispensing head according to claim 8.

11. The reservoir has a filter member positioned to cover the opening of the connection portion. A droplet dispensing head according to any one of claims 1 to 3.

12. A droplet dispensing head according to any one of claims 1 to 3, A control unit for controlling the droplet dispensing head, A droplet dispensing device equipped with the following features.