Droplet ejection head and droplet ejection device

Abstract

A droplet ejection head according to the present disclosure has a head body, a driver IC, and a head cover. The head body has a plurality of ejection holes through which droplets are ejected. The driver IC controls driving of the head body. The head cover is positioned on the head body. The head cover integrally has a first side wall, a second side wall, a third side wall, and a fourth side wall. The first side wall is positioned on one-end side of the head body in the longitudinal direction. The second side wall is positioned on the other-end side of the head body in the longitudinal direction. The third side wall is positioned on one-end side of the head body in the lateral direction, and is continuous with the first side wall and the second side wall. The fourth side wall is positioned on the other-end side of the head body in the lateral direction, and is continuous with the first side wall and the second side wall.

Description

Droplet ejection head and droplet ejection device

[0001] The present disclosure relates to a droplet ejection head and a droplet ejection device.

[0002] Conventionally, liquid 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 a liquid ejection head that has a housing disposed on the head body and having an opening on its side, and a heat sink disposed in the opening to dissipate heat generated by a driver IC.

[0003] WO 2016 / 104480

[0004] A droplet ejection head according to one aspect of the present disclosure includes a head body, a driver IC, and a head cover. The head body has a plurality of ejection holes through which droplets are ejected. The driver IC controls the driving of the head body. The head cover is located on top of the head body. The head cover integrally includes a first side wall, a second side wall, a third side wall, and a fourth side wall. The first side wall is located at one end of the head body in the longitudinal direction. The second side wall is located at the other end of the head body in the longitudinal direction. The third side wall is located at one end of the head body in the lateral direction and is continuous with the first side wall and the second side wall. The fourth side wall is located at the other end of the head body in the lateral direction and is continuous with the first side wall and the second side wall.

[0005] FIG. 1 is a diagram schematically showing an example of the configuration of a droplet ejection device according to the first embodiment. FIG. 2 is an exploded perspective view showing a schematic configuration of a droplet ejection head according to the first embodiment. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a plan view showing an example of the configuration of a head cover according to the first embodiment. FIG. 6 is a schematic view for explaining fixing points between the droplet ejection head according to the first embodiment and a robot arm. FIG. 7 is a plan view showing an example of the configuration of a head cover according to the second embodiment. FIG. 8 is a plan view showing another example of the configuration of a head cover according to the second 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] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision or installation precision.

[0008] In the drawings referred to below, for ease of understanding, the X-axis, Y-axis, and Z-axis directions are defined as being orthogonal to each other, and an orthogonal coordinate system is shown in which the positive Z-axis direction is the vertically upward direction. The rotation direction around the vertical axis is also referred to as the θ direction.

[0009] Conventionally, liquid 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 a liquid ejection head that has a housing disposed on the head body and having an opening on its side, and a heat sink disposed in the opening to dissipate heat generated by a driver IC.

[0010] However, as described in Patent Document 1, there is room for further improvement in terms of increasing the rigidity of a droplet ejection head in which the housing and the heat sink are provided separately. If the rigidity of the droplet ejection head is low, for example, the amount of deflection of the nozzle surface may increase, which may result in ejection defects or reduced printing accuracy.

[0011] First Embodiment <External Configuration Example of Droplet Discharge Device> A configuration example of a droplet discharge device according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram schematically illustrating a configuration example of a droplet discharge device according to the first embodiment.

[0012] As shown in FIG. 1, the droplet discharge device 100 includes a robot arm 1 , a droplet discharge head 3 , and a control device 4 .

[0013] The robot arm 1 is mounted on a base 5, which is placed on a horizontal floor surface, for example, indoors or outdoors. The robot arm 1 holds a droplet discharge head 3. The robot arm 1 is, for example, a vertical articulated robot. The robot arm 1 has an arm unit 11. The arm unit 11 is composed of multiple parts assembled so that they can bend, stretch, and rotate freely. The arm unit 11 can move the droplet discharge head 3 mounted on the tip 101 of the arm unit 11, or change the position, posture, and angle of the droplet discharge head 3, in accordance with commands from a control unit 4a (described later). The arm unit 11 illustrated in FIG. 1 is not particularly limited to the configuration shown in FIG. 1, as long as it has the degree of freedom to move the droplet discharge head 3 required for the droplet discharge head 3, or to change the position, posture, and angle of the droplet discharge head 3.

[0014] The robot arm 1 can move the droplet discharge head 3 mounted on the tip 101 of the arm unit 11 in the vertical direction (Z-axis direction) by, for example, moving the droplet discharge head 3 mounted on the tip 101 of the arm unit 11 along a predetermined rotation axis. As a result, the droplet discharge head 3 can assume a position in which the liquid discharge surface 3SF of the droplet discharge head 3 faces parallel to the spray surface 6SF of the target 6, as shown in FIG. 1 . The robot arm 1 can also rotate the droplet discharge head 3 mounted on the tip 101 of the arm unit 11 around a predetermined rotation axis by using the arm unit 11. As a result, the droplet discharge head 3 can be swapped between its longitudinal and lateral positions, or its upside-down position can be reversed, for example.

[0015] The droplet ejection head 3 is attached to the tip 101 of the arm unit 11 of the robot arm 1. The droplet ejection head 3 ejects a liquid in the form of droplets onto the target object 6. The liquid is, for example, a liquid that can be applied to the target object 6 to color it. For example, ink or paint can be used as the liquid. The liquid may be a liquid with a higher viscosity than in a standard state.

[0016] The control device 4 is, for example, a computer, and includes a control unit 4a such as a processor and a storage unit 4b such as a memory. The storage unit 4b stores programs that control various processes executed in the droplet ejection device 100. The control unit 4a controls the operation of the droplet ejection device 100 by reading and executing the programs stored in the storage unit 4b.

[0017] The program may be recorded on a computer-readable storage medium and installed from the storage medium into the storage unit 4b of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[0018] The droplet ejection device 100 may also have a circulation mechanism (not shown) that supplies liquid to the droplet ejection head 3 while controlling the flow rate of the liquid circulating between the droplet ejection device 100 and the droplet ejection head 3 .

[0019] <Configuration of droplet ejection head> Next, the configuration of the droplet ejection head 3 according to the first embodiment will be described with reference to Fig. 2 to Fig. 4. Fig. 2 is an exploded perspective view showing the schematic configuration of the droplet ejection head 3 according to the first embodiment. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2.

[0020] The droplet ejection head 3 includes a head body 20, a wiring section 30, a head cover 40, and a protective member 45. The head body 20 includes a flow path member 21, a piezoelectric actuator substrate (not shown), and a reservoir 23.

[0021] In the following description, for convenience, the direction in which the head body 20 is provided in the droplet ejection head 3 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."

[0022] The flow path member 21 of the head main body 20 has a generally flat plate shape and has a first surface 21a (see FIG. 3) which is one main surface, and a second surface 21b (see FIG. 3) located on the opposite side of the first surface. The first surface 21a has an opening (not shown), and liquid is supplied from a reservoir 23 to the inside of the flow path member 21 through this opening.

[0023] The second surface 21b has a plurality of ejection holes (not shown) that eject liquid 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 21a to the second surface 21b.

[0024] The piezoelectric actuator substrate is located on the first surface 21a 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.

[0025] A reservoir 23 is positioned on the piezoelectric actuator substrate. The reservoir 23 has openings 23a at both ends in the main scanning direction, which is perpendicular to the sub-scanning direction, which is the transport direction of the printing paper P, and which is parallel to the printing paper P. The reservoir 23 has a flow path therein, and liquid is supplied from the outside through the openings 23a. The reservoir 23 supplies liquid to the flow path member 21. The reservoir 23 also stores the liquid supplied to the flow path member 21.

[0026] When printing, the liquid may be supplied from one opening 23 a while the other opening 23 a is closed. Alternatively, the liquid may be supplied from both openings 23 a. When initially introducing the liquid into the droplet ejection head 3, if the liquid is supplied from one opening 23 a and then collected from the other opening 23 a, air and storage liquid that were in the flow path inside the reservoir 23 can easily escape from the flow path, making it easier to introduce the liquid into the droplet ejection head 3.

[0027] Furthermore, during printing, liquid may be supplied from one opening 23a and recovered from the other opening 23a. In this way, it is possible to prevent air bubbles from accumulating in the flow path inside the reservoir 23. Furthermore, by supplying liquid adjusted to a constant temperature, it is possible to stabilize the temperature of the droplet discharge head 3. The recovered liquid may be passed through a filter or the like and then supplied again to the droplet discharge head 3. In other words, the liquid may be circulated. The supply and recovery of liquid to the droplet discharge head 3, or the circulation of the liquid, may be controlled by the control unit 4a.

[0028] Furthermore, liquid may be supplied from the reservoir 23 to the flow path member 21, and liquid may be recovered from the flow path member 21 to the reservoir 23. Furthermore, liquid may be supplied to and recovered from the flow path facing the nozzles (ejection holes) within the flow path member 21, so that liquid is less likely to stagnate within the nozzles and their surroundings. In such an embodiment, liquid is supplied from the outside to the droplet ejection head 3 as a whole, some of the liquid is ejected from the ejection holes, and the liquid that is not ejected is recovered externally.

[0029] The wiring section 30 has a flexible substrate 31, a wiring substrate 32, a plurality of driver ICs 33, a pressing member 34, and an elastic member 35 (see FIG. 3). The flexible substrate 31 transmits a predetermined signal sent from the outside to the head main body 20. As shown in FIG. 2, the droplet ejection head 3 according to this embodiment has two flexible substrates 31.

[0030] One end of the flexible substrate 31 is electrically connected to the piezoelectric actuator substrate of the head main body 20. The other end of the flexible substrate 31 is pulled upward through the slit portion 23b of the reservoir 23 and is electrically connected to the wiring substrate 32. This allows the piezoelectric actuator substrate of the head main body 20 to be electrically connected to the outside.

[0031] The wiring board 32 is located above the head body 20. The wiring board 32 distributes signals to a plurality of driver ICs 33.

[0032] 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 3 according to the embodiment, three driver ICs 33 are provided on each flexible substrate 31. Note that the number of driver ICs 33 provided on one flexible substrate 31 is not limited to three.

[0033] The driver IC 33 drives the piezoelectric actuator substrate of the head main body 20 based on a drive signal sent from the control unit 4a (see FIG. 1). In this way, the driver IC 33 drives the droplet ejection head 3.

[0034] 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 drawn out from the slit portion 23b, and presses the driver IC 33 on the flexible substrate 31 toward the third side wall 43 and the fourth side wall 44 of the head cover 40. This brings the driver IC 33 into close contact with the head cover 40, allowing heat generated when the driver IC 33 is driven to be efficiently dissipated to the head cover 40.

[0035] The elastic member 35 (see FIG. 3) is provided so as to contact the side wall portions 34a, 34b (see FIG. 3) of the pressing member 34. By providing such elastic member 35, it is possible to reduce the possibility that the pressing member 34 will damage the flexible substrate 31 when pressing the driver IC 33.

[0036] The elastic member 35 is made of, for example, double-sided foam tape. Furthermore, by using, for example, a non-silicon heat conductive sheet as the elastic member 35, it is possible to improve the heat dissipation of the driver IC 33. However, the elastic member 35 is not necessarily required.

[0037] The head cover 40 is attached to the head body 20. Specifically, the head cover 40 is attached to the head body 20 so as to cover the wiring portion 30 located on the head body 20, for example, the flexible substrate 31 drawn out from the slit portion 23b, the wiring substrate 32, and the pressing member 34. This enables the head cover 40 to seal the wiring portion 30. The head cover 40 is made of, for example, resin or metal.

[0038] The head cover 40 has a rectangular cylindrical shape that opens in the vertical direction (here, the Z-axis direction) and extends long in the main scanning direction (here, the Y-axis direction). Specifically, the head cover 40 has a first opening 40a on its bottom surface and a second opening 40b on its top surface. The head cover 40 also has four integral side walls 41 to 44. As described above, the third side wall 43 and the fourth side wall 44, which face each other along the sub-scanning direction, are provided so as to contact the driver IC 33 and function as heat sinks that dissipate heat generated by the driver IC 33. In other words, the head cover 40 functions as a heat sink that dissipates heat generated by the driver IC 33. Therefore, the droplet ejection head 3 does not need to be provided with a separate heat sink.

[0039] The first opening 40a is positioned to face the reservoir 23. The flexible substrate 31 and the pressing member 34 are inserted through the first opening 40a.

[0040] The second opening 40b is provided for inserting a connector (not shown) provided on the wiring board 32. If the space between the connector and the second opening 40b is sealed with resin or the like, it becomes difficult for liquid or dust to enter the inside of the head cover 40. Note that the second opening 40b does not necessarily have to be provided. The first opening 40a and the second opening 40b may be different in size.

[0041] In this way, the droplet ejection head 3 according to the first embodiment is configured with an integrated heat sink and head cover, unlike conventional droplet ejection heads. This configuration improves the rigidity of the droplet ejection head 3 compared to conventional droplet ejection heads in which the head cover and heat sink are separable. The head cover 40 according to the first embodiment also has a larger volume and a larger heat capacity than the heat sinks of conventional droplet ejection heads. Furthermore, the head cover 40 according to the first embodiment has a larger heat transfer area than the heat sinks of conventional droplet ejection heads, thereby improving heat dissipation efficiency. The detailed configuration of the head cover 40 will be described later.

[0042] The protective member 45 covers the periphery of the head main body 20. By providing the protective member 45 in the droplet ejection head 3 according to the first embodiment, it is possible to protect the head main body 20, which is structurally weaker in the droplet ejection head 3. However, the protective member 45 is not necessarily provided. The detailed configuration of the protective member 45 will be described later.

[0043] 2 shows an example of the configuration of the droplet ejection head 3, and may further include members other than those shown in FIG.

[0044] Next, the configuration of the head cover 40 according to the first embodiment will be described with further reference to Fig. 5. Fig. 5 is a plan view showing an example of the configuration of the head cover 40 according to the first embodiment.

[0045] The head cover 40 integrally includes a first side wall 41, a second side wall 42, a third side wall 43, and a fourth side wall 44. The first side wall 41 is located at one end of the head body 20 in the longitudinal direction (here, the negative Y-axis side). The second side wall 42 is located at the other end of the head body 20 in the longitudinal direction (here, the positive Y-axis side). The third side wall 43 is located at one end of the head body 20 in the lateral direction (here, the negative X-axis side). The third side wall 43 is continuous with the first side wall 41 at one end of the head body 20 in the longitudinal direction and is continuous with the second side wall 42 at the other end of the head body 20 in the longitudinal direction. The fourth side wall 44 is located at the other end of the head body 20 in the lateral direction (here, the positive X-axis side). The fourth side wall 44 is continuous with the first side wall 41 at one end of the head body 20 in the longitudinal direction, and is continuous with the second side wall 42 at the other end of the head body 20 in the longitudinal direction.

[0046] The droplet ejection head 3 may further include a cooling path 50 located inside the head cover 40. Specifically, as shown in FIG. 5 , the cooling path 50 may include a second flow path 52, a third flow path 53, and a fourth flow path 54. The second flow path 52 is located inside the second side wall 42 and extends along the short direction of the head main body 20. The third flow path 53 is located inside the third side wall 43 and extends along the long direction of the head main body 20. As shown in FIG. 3 , the third flow path 53 is provided at a position facing the driver IC 33 across the third side wall 43. The fourth flow path 54 is located inside the fourth side wall 44 and extends along the long direction of the head main body 20. The fourth flow path 54 is provided at a position facing the driver IC 33 across the fourth side wall 44.

[0047] The cooling path 50 may have a first opening 41 a and a second opening 41 b in the first side wall 41. The cooling path 50 may be a flow path that extends from the first opening 41 a through the interiors of the fourth side wall 44, the second side wall 42, and the third side wall 43 to the second opening 41 b.

[0048] Gas or liquid for cooling the driver IC 33 is supplied to the cooling path 50 through the first opening 41 a. The gas or liquid supplied through the first opening 41 a passes through the fourth flow path 54, the second flow path 52, and the third flow path 53, and flows out of the head cover 40 through the second opening 41 b. Note that both the gas and the liquid may be supplied to the cooling path 50 at the same time.

[0049] With this configuration, the heat dissipation efficiency of the droplet ejection head 3 can be further improved.

[0050] The head cover 40 may have a first flange 61 and a second flange 62. The first flange 61 protrudes inward in the longitudinal direction of the head main body 20 from the first side wall 41. Specifically, the first flange 61 is located at the upper end of the first side wall 41 and protrudes from the first side wall 41 in the positive Y-axis direction. The second flange 62 protrudes inward in the longitudinal direction of the head main body 20 from the second side wall 42. Specifically, the second flange 62 is located at the upper end of the second side wall 42 and protrudes from the second side wall 42 in the negative Y-axis direction. The first flange 61 and the second flange 62 increase the volume of the head cover 40, thereby increasing the heat transfer area from the driver IC 33 and improving heat dissipation efficiency. Furthermore, when the head cover 40 is fixed to the robot arm 1, the area of ​​the surface facing the tip end 101 of the robot arm 1 is increased, allowing more heat generated from the driver IC 33 to be dissipated to the robot arm 1. Furthermore, since the first flange 61 and the second flange 62 protrude inward in the longitudinal direction of the head body 20, the longitudinal length of the head cover 40 does not increase, and the head cover 40 can be prevented from becoming large.

[0051] As shown in FIG. 4 , the head cover 40 may have a third flange 63 and a fourth flange 64. The third flange 63 protrudes outward in the short-side direction of the head body 20 from the third side wall 43. Specifically, the third flange 63 is located at the upper end of the third side wall 43 and protrudes from the third side wall 43 in the negative direction of the X axis. The fourth flange 64 protrudes outward in the short-side direction of the head body 20 from the fourth side wall. Specifically, the fourth flange 64 is located at the upper end of the fourth side wall 44 and protrudes from the fourth side wall 44 in the positive direction of the X axis. The third flange 63 and the fourth flange 64 function as fixing parts to the tip portion 101 of the robot arm 1. This point will be described later.

[0052] The head cover 40 and the head body 20 may be joined via a joining member 70. The joining member 70 is, for example, an O-ring. The joining member 70 may be made of a material with lower thermal conductivity than the head cover 40 or the head body 20. With this configuration, it is possible to reduce heat transfer from the head cover 40 to the head body 20.

[0053] Next, the configuration of the protection member 45 according to the first embodiment will be described with reference to FIGS.

[0054] The protective member 45 protects the head main body 20. Specifically, as shown in Figures 3 and 4, the protective member 45 protects the side surfaces of the flow path member 21 and the reservoir 23. By having the protective member 45, the droplet ejection head 3 according to the first embodiment can protect the head main body 20, which is structurally weaker in the droplet ejection head 3, and can improve the rigidity of the entire droplet ejection head 3.

[0055] As shown in FIG. 2 , the protective member 45 is a box-shaped member that extends elongatedly in the main scanning direction (Y-axis direction) and has an open top. It has a bottom 45b and a peripheral wall 45a that stands up from the bottom 45b. As shown in FIG. 3 , the bottom 45b has an opening 45c. The flow path member 21 is positioned to close the opening 45c. The peripheral wall 45a is positioned to surround the periphery of the bottom 45b and covers the periphery of the reservoir 23 of the head main body 20. The protective member 45 is attached from the underside of the droplet ejection head 3 so as to cover the reservoir 23 and the flow path member 21, and may be fixed to the reservoir 23 at both longitudinal ends of the head main body 20 using fixing members 90 such as bolts or screws (see FIG. 4 ).

[0056] The height position of the protective member 45 , specifically the height position of the upper end of the peripheral wall portion 45 a may be located above the height position of the boundary surface between the head main body 20 and the head cover 40 .

[0057] With this configuration, the rebounded ink and the like are less likely to invade through the boundary between the head main body 20 and the head cover 40 .

[0058] As shown in FIG. 3 , the dimension of the head cover 40 in the short direction of the head body 20 may be larger than the dimension of the head body 20 .

[0059] According to this configuration, the protective member 45 and the head main body 20 are unlikely to come into contact with each other, and therefore the head main body 20 is unlikely to be subjected to external pressure from the protective member 45 .

[0060] The protective member 45 may be electrically connected to the head main body 20. With this configuration, the protective member 45 in the droplet ejection head 3 can be prevented from floating electrically.

[0061] The protective member 45 may further have a plurality of ribs 45d. The plurality of ribs 45d protrude from the inner wall of the peripheral wall portion 45a toward the head main body 20. The plurality of ribs 45d are positioned at equal intervals on the inner wall of the peripheral wall portion 45a. By having such a plurality of ribs 45d, the pressure applied to the protective member 45 from the head main body 20 can be distributed and received by the plurality of ribs 45d.

[0062] 3, the peripheral wall portion 45a may be inclined so as to move away from the head main body 20 as it moves away from the second surface 21b of the flow path member 21, on which the plurality of ejection holes are located, in a direction perpendicular to the second surface 21b (here, the positive direction of the Z axis). With this configuration, the contact area between the head main body 20 and the protective member 45 can be reduced, and therefore, pressure received by the protective member 45 is less likely to be transmitted to the head main body 20.

[0063] Next, the fixing points between the droplet ejection head 3 and the robot arm 1 according to the first embodiment will be described with reference to Fig. 6. Fig. 6 is a schematic diagram for explaining the fixing points between the droplet ejection head 3 and the robot arm 1 according to the first embodiment.

[0064] 6 , the droplet discharge device 100 may be configured such that the robot arm 1 is positioned so that the tip 101 of the robot arm 1 faces downward, and the droplet discharge head 3 held by the tip 101 is fixed to the tip 101 using fixing members 80 such as bolts or screws that extend upward from the underside of the droplet discharge head 3. Specifically, the fixing members 80 are inserted into through-holes 63 a, 64 a (see FIG. 2 ) in the third flange 63 and the fourth flange 64 of the head cover 40 of the droplet discharge head 3, and are screwed into screw holes (not shown) formed in the tip 101 of the robot arm 1. In this way, the head cover 40 is fixed to the robot arm 1.

[0065] The fourth flange 64 may have a positioning hole 64b. A positioning pin 102 may be provided on the surface of the tip 101 of the robot arm 1 facing the droplet discharge head 3 at a position facing the positioning hole 64b.

[0066] The positioning pins 102 are fitted into the positioning holes 64b to position the head cover 40. The positioning holes 64b may be provided in the third flange 63, or may be provided in both the third flange 63 and the fourth flange 64.

[0067] The droplet ejection device 100 may further include a supply path 110 that supplies gas to the inside of the robot arm 1. In this case, the cooling path 50 may be connected to the supply path 110. With this configuration, the gas supplied to the inside of the robot arm 1 can also be used as the gas supplied to the head cover 40, so the amount of gas used in the droplet ejection head 3 can be reduced.

[0068] As described above, the droplet ejection head 3 according to the first embodiment is configured such that the heat sink and head cover of a conventional droplet ejection head are integrated into one piece. This configuration improves the rigidity of the droplet ejection head 3 compared to conventional droplet ejection heads in which the head cover and heat sink are each configured to be separable.

[0069] Second Embodiment Fig. 7 is a plan view showing an example of the configuration of the head cover 40 according to the second embodiment. Fig. 8 is a plan view showing another example of the configuration of the head cover 40 according to the second embodiment. As shown in Fig. 7 , the cooling path 50 may pass not only through the second side wall 42, the third side wall 43, and the fourth side wall 44, but also through the inside of the first side wall 41.

[0070] Specifically, the cooling path 50 may further include a first flow path 51. The first flow path 51 is located inside the first side wall 41 and extends along the short direction of the head body 20. The cooling path 50 may include a first opening 41a in the first side wall 41 and a third opening 43a in the fourth side wall 44. The cooling path 50 may extend from the first opening 41a through the fourth side wall 44, the second side wall 42, the third side wall 43, and the interior of the first side wall 41 to the third opening 43a. In other words, gas or liquid supplied from the first opening 41a passes through the fourth flow path 54, the second flow path 52, the third flow path 53, and the first flow path 51 before flowing out of the head cover 40 from the third opening 43a.

[0071] According to this configuration, the heat dissipation efficiency of the droplet ejection head 3 can be further improved.

[0072] 8 , the first flow path 51 of the cooling path 50 may be connected to the third flow path 53 and the fourth flow path 54. Specifically, one end of the first flow path 51 may be connected to the third flow path 53, and the other end of the first flow path 51 may be connected to the fourth flow path 54.

[0073] The present technology may also be configured as follows. (1) A droplet ejection head (for example, the droplet ejection head 3) includes a head body (for example, the head body 20), a driver IC (for example, the driver IC 33), and a head cover (for example, the head cover 40). The head body has a plurality of ejection holes from which droplets are ejected. The driver IC controls the driving of the head body. The head cover is located on the head body. The head cover integrally includes a first side wall (for example, the first side wall 41), a second side wall (for example, the second side wall 42), a third side wall (for example, the third side wall 43), and a fourth side wall (for example, the fourth side wall 44). The first side wall is located at one end of the head body in the longitudinal direction. The second side wall is located at the other end of the head body in the longitudinal direction. The third side wall is located at one end of the head body in the short direction and is continuous with the first side wall and the second side wall. The fourth side wall is located at the other end of the head body in the short direction and is continuous with the first side wall and the second side wall. (2) The droplet ejection head described in (1) above may have a cooling path (e.g., cooling path 50) located inside the head cover. (3) In the droplet ejection head described in (2) above, the cooling path may include a third flow path located inside the third side wall and extending along the longitudinal direction of the head body, a second flow path located inside the second side wall and extending along the short direction of the head body, and a fourth flow path located inside the fourth side wall and extending along the longitudinal direction of the head body. (4) In the droplet ejection head described in (3) above, the cooling path may have a first opening and a second opening in the first side wall and extend from the first opening through the fourth side wall, the second side wall, and the third side wall to the second opening. (5) In the droplet ejection head described in (3) or (4) above, the cooling path may include a first flow path located inside the first side wall and extending along the longitudinal direction of the head body. (6) In the droplet ejection head described in any one of (1) to (5) above, the head cover may have a first flange (for example, first flange 61) protruding inward in the longitudinal direction of the head body from the first side wall, and a second flange (for example, second flange 62) protruding inward in the longitudinal direction of the head body from the second side wall.(7) In the droplet ejection head described in any one of (1) to (6) above, the head cover may have a third flange (e.g., third flange 63) protruding outward in the short direction of the head body from the third side wall, and a second flange (e.g., fourth flange 64) protruding outward in the short direction of the head body from the fourth side wall. (8) In the droplet ejection head described in any one of (1) to (7) above, the head cover and the head body are joined via a joining member (e.g., joining member 70) having a lower thermal conductivity than the head cover or the head body. (9) The droplet ejection head described in (1) above may further have a protective member (e.g., protective member 45) covering the periphery of the head body. (10) In the droplet ejection head described in (9) above, the height position of the protective member may be located above the height position of the interface between the head body and the head cover. (11) In the droplet ejection head described in (9) above, the height position of the protective member may be located higher than the height position of the head body, and the dimension of the head cover in the short direction of the head body may be larger than the dimension of the head body. (12) In the droplet ejection head described in any one of (9) to (11) above, the protective member may be electrically connected to the head body. (13) In the droplet ejection head described in any one of (9) to (12) above, the protective member may have a peripheral wall portion (for example, peripheral wall portion 45a) that covers the periphery of the head body, and the peripheral wall portion may be inclined so as to move away from the head body as it moves away from the ejection surface of the head body on which the ejection holes are located in a direction perpendicular to the ejection surface. (14) A droplet ejection device (for example, droplet ejection device 100) may have the droplet ejection head described in any one of (1) to (13) above, a control unit (for example, control unit 4a) that controls the droplet ejection head, and a robot arm (for example, robot arm 1) that holds the droplet ejection head, and the head cover may be fixed to the robot arm. (15) The droplet ejection device described in (14) above may have a cooling path located inside the head cover and a supply path (for example, supply path 110) that supplies gas to the inside of the robot arm, and the cooling path may be connected to the supply path.(16) In the droplet ejection device described in (14) or (15) above, the head cover has a third flange protruding outward in the short direction of the head body from the third side wall, and a fourth flange protruding outward in the short direction of the head body from the fourth side wall, and the third flange or the fourth flange has a positioning hole (for example, positioning hole 64b), and the surface of the robot arm facing the droplet ejection head may have a positioning pin (for example, positioning pin 102) at a position corresponding to the positioning hole.

[0074] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. For example, the droplet ejection head may be used in a device that forms a wiring pattern by applying a metal material instead of ink, or in a 3D printer by applying a resin or the like. Furthermore, while the droplet ejection head has been used in an arm-mounted droplet ejection device, the droplet ejection head may also be used in a rail-mounted droplet ejection device that ejects droplets during reciprocating motion.

[0075] 3 Droplet ejection head 1 Robot arm 20 Head body 21 Flow path member 23 Reservoir 40 Head cover 41 First side wall 42 Second side wall 43 Third side wall 44 Fourth side wall 100 Droplet ejection device

Claims

1. A droplet ejection head having a plurality of ejection holes from which droplets are ejected, a driver IC that controls driving of the head body, and a head cover positioned above the head body, the head cover integrally having a first side wall positioned on one end side in the longitudinal direction of the head body, a second side wall positioned on the other end side in the longitudinal direction of the head body, a third side wall positioned on one end side in the lateral direction of the head body and continuous with the first side wall and the second side wall, and a fourth side wall positioned on the other end side in the lateral direction of the head body and continuous with the first side wall and the second side wall.

2. The droplet ejection head according to claim 1, having a cooling channel positioned inside the head cover.

3. The cooling channel includes a third flow channel positioned inside the third side wall and extending along the longitudinal direction of the head body, a second flow channel positioned inside the second side wall and extending along the lateral direction of the head body, and a fourth flow channel positioned inside the fourth side wall and extending along the longitudinal direction of the head body, the droplet ejection head according to claim 2.

4. The cooling channel has a first opening and a second opening in the first side wall, and reaches the second opening from the first opening through the inside of the fourth side wall, the second side wall, and the third side wall, the droplet ejection head according to claim 3.

5. The cooling channel includes a first flow channel positioned inside the first side wall and extending along the longitudinal direction of the head body, the droplet ejection head according to claim 3 or 4.

6. The head cover has a first flange protruding inward in the longitudinal direction of the head body from the first side wall and a second flange protruding inward in the longitudinal direction of the head body from the second side wall, the droplet ejection head according to any one of claims 1 to 5.

7. The head cover has a third flange protruding outward in the lateral direction of the head body from the third side wall and a fourth flange protruding outward in the lateral direction of the head body from the fourth side wall, the droplet ejection head according to any one of claims 1 to 6.

8. The head cover and the head body are joined via a joining member having a lower thermal conductivity than the head cover or the head body, the droplet ejection head according to any one of claims 1 to 7.

9. The droplet discharge head according to claim 1, further comprising a protective member that covers the periphery of the head body.

10. The droplet discharge head according to claim 9, wherein the height position of the protective member is located above the height position of the boundary surface between the head body and the head cover.

11. The droplet discharge head according to claim 9, wherein the height position of the protective member is located above the height position of the head body, and in the lateral direction of the head body, the dimension of the head cover is larger than the dimension of the head body.

12. The droplet discharge head according to any one of claims 9 to 11, wherein the protective member is electrically connected to the head body.

13. The protective member has a peripheral wall portion that covers the periphery of the head body, and the peripheral wall portion is inclined so as to be separated from the head body as it moves away from the discharge surface of the head body where the discharge holes are located in a direction orthogonal to the discharge surface. The droplet discharge head according to any one of claims 9 to 12.

14. A droplet discharge device comprising the droplet discharge head according to any one of claims 1 to 13, a control unit that controls the droplet discharge head, and a robot arm that holds the droplet discharge head, wherein the head cover is fixed to the robot arm.

15. The droplet discharge device according to claim 14, further comprising a cooling path located inside the head cover and a supply path that supplies gas inside the robot arm, wherein the cooling path is connected to the supply path.

16. The head cover has a third flange that protrudes outward in the lateral direction of the head body from the third side wall and a fourth flange that protrudes outward in the lateral direction of the head body from the fourth side wall, and the third flange or the fourth flange has a positioning hole. On the surface of the robot arm facing the droplet discharge head, there is a positioning pin at a position corresponding to the positioning hole. The droplet discharge device according to claim 14 or 15.

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