Droplet ejection head and droplet ejection device

Abstract

A droplet ejection head according to the present disclosure comprises a head body, a driver IC, and an electrical component chamber. The head body has a flow channel member and a reservoir. The flow channel member has a plurality of ejection holes. The reservoir has a reservoir flow channel located above the flow channel member and connected to the flow channel member. The driver IC controls driving of the head body. The electrical component chamber houses the driver IC and is partitioned by a part of the reservoir. The reservoir has a partition wall positioned between the electrical component chamber and the reservoir flow channel, and a cavity part positioned in at least a part of the partition 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] 2. Description of the Related Art Known printing devices include inkjet printers and inkjet plotters that use an inkjet recording method. These inkjet printing devices are equipped with a droplet ejection head for ejecting liquid.

[0003] Japanese Patent Application Laid-Open No. 2020-001315

[0004] A droplet ejection head according to one aspect of the present disclosure includes a head body, a driver IC, and an electrical equipment chamber. The head body has a flow path member and a reservoir. The flow path member has a plurality of ejection holes. The reservoir is located above the flow path member and has a reservoir flow path connected to the flow path member. The driver IC controls the driving of the head body. The electrical equipment chamber houses the driver IC and is partitioned by a portion of the reservoir. The reservoir has a partition wall located between the electrical equipment chamber and the reservoir flow path, and a hollow portion located in at least a portion of the partition wall.

[0005] FIG. 1 is a diagram schematically showing an example of the configuration of a droplet ejection device according to a 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 perspective view showing a schematic configuration of a droplet ejection head according to the first embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a schematic plan view showing the configuration of a reservoir according to the first embodiment. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. FIG. 8 is a schematic cross-sectional view showing the configuration of a droplet ejection head according to a second embodiment. FIG. 9 is a schematic plan view showing the configuration of a reservoir according to a third 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, 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] Japanese Patent Application Laid-Open No. 2006-103663 discloses a liquid jet head including a flow path forming substrate that forms various flow paths in the head, an ink receiving chamber that supplies ink to the flow path forming substrate, and an ink storage chamber that stores ink discharged from the flow path forming substrate. Hereinafter, the ink receiving chamber and the ink storage chamber are collectively referred to as a reservoir. Furthermore, between the ink receiving chamber and the ink storage chamber, there is a space (hereinafter referred to as an electrical equipment chamber) in which lead electrodes, a protective substrate, etc. are disposed.

[0010] However, in the liquid jet head described in Patent Document 1, if the liquid inside the reservoir leaks, the leaked liquid may seep into the electrical equipment chamber, which could result in, for example, the liquid jet head not operating normally.

[0011] Therefore, it is desirable to provide a droplet ejection head that, when liquid leaks from the reservoir, makes it difficult for the liquid to infiltrate into the interior of the electrical equipment chamber.

[0012] First Embodiment <External Configuration Example of Droplet Discharge Device> A configuration example of a droplet discharge device 100 according to a first embodiment will be described using Fig. 1. Fig. 1 is a diagram schematically showing a configuration example of a droplet discharge device 100 according to the first embodiment.

[0013] 1, the droplet discharge device 100 includes a robot arm 1, a circulation mechanism 2, a droplet discharge head 3, and a control device 4. The robot arm 1 is an example of an arm.

[0014] 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. In other words, the droplet discharge head 3 is mounted on the robot arm 1. 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 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, which will be 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 or change the position, posture, and angle required for the droplet discharge head 3.

[0015] The robot arm 1 can move the circulation mechanism 2 and the droplet discharge head 3 mounted on the tip of the arm unit 11 in the vertical direction (Z-axis direction) by, for example, moving them along a predetermined rotation axis using the arm unit 11. As a result, the circulation mechanism 2 and the droplet discharge head 3 can be oriented such that the liquid discharge surface 3SF of the droplet discharge head 3 faces parallel to the spray surface 6SF of the target object 6, as shown in FIG. 1 . The robot arm 1 can also rotate the circulation mechanism 2 and the droplet discharge head 3 mounted on the tip of the arm unit 11 around a predetermined rotation axis using the arm unit 11. As a result, the circulation mechanism 2 and the droplet discharge head 3 can be swapped between their longitudinal and lateral positions, or their upside-down positions can be reversed, for example.

[0016] The circulation mechanism 2 is installed at the tip of the arm portion 11 of the robot arm 1. The circulation mechanism 2 supplies the liquid to the droplet discharge head 3 while controlling the circulation flow rate of the liquid circulating between the circulation mechanism 2 and the droplet discharge head 3.

[0017] The droplet ejection head 3 is attached to a circulation mechanism 2 installed at the tip of the arm section 11 of the robot arm 1. The droplet ejection head 3 ejects a liquid in the form of droplets onto an object 6. The liquid is, for example, a liquid that can be applied to the 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.

[0018] 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.

[0019] 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.

[0020] <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 Figs. 2 to 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 perspective view showing the schematic configuration of the droplet ejection head 3 according to the first embodiment. Fig. 4 is a cross-sectional view taken along line IV-IV in Fig. 2. Note that, for ease of understanding, the first groove portion 27 is omitted from Fig. 4.

[0021] The droplet ejection head 3 includes a head main body 20, an electrical component section 30, and an electrical component protection cover 40. The head main body 20 includes a flow path member 21, a piezoelectric actuator substrate (not shown), and a reservoir 23.

[0022] In the following description, for convenience, the direction in which the head main body 20 is provided in the droplet ejection head 3 may be referred to as "downward," and the direction in which the electrical protection cover 40 is provided relative to the head main body 20 may be referred to as "upward."

[0023] The flow path member 21 of the head main body 20 has, for example, a substantially flat plate shape. An opening (not shown) is located on one main surface 21a (see FIG. 4) of the flow path member 21, and liquid is supplied from the reservoir 23 to the inside of the flow path member 21 through this opening. A plurality of ejection holes (not shown) that eject liquid onto the printing paper P are located on the other main surface 21b (see FIG. 4) of the flow path member 21. The flow path member 21 has therein a flow path 21c (see FIG. 4) that allows liquid to flow from the one main surface 21a to the other main surface 21b. The one main surface 21a is an example of a third surface that faces the reservoir 23.

[0024] A piezoelectric actuator substrate (not shown) is located on one main 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 electrical component section 30 is electrically connected to the piezoelectric actuator substrate.

[0025] A reservoir 23 is located on the piezoelectric actuator substrate. The reservoir 23 has a first surface 231 facing the piezoelectric actuator substrate and a second surface 232 located opposite the first surface 231. The second surface 232 of 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 parallel to the printing paper P. The reservoir 23 has reservoir flow paths 23c and 23d inside, and liquid is supplied from the outside through the openings 23a. The reservoir flow paths 23c and 23d are connected to the flow path 21c of the flow path member 21 (see FIG. 4). 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. The reservoir 23 has a layered structure in which multiple plates are stacked. A detailed configuration of the reservoir 23 will be described later.

[0026] The electrical equipment 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. 4). The electrical equipment section 30 is housed in a part of the reservoir 23, for example, an electrical equipment chamber 30a (see FIG. 4) partitioned by a slit portion 23b. 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.

[0027] 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.

[0028] The wiring board 32 is located above the head body 20. The wiring board 32 distributes signals to a plurality of driver ICs 33.

[0029] The plurality of driver ICs 33 are located on one main surface of the flexible substrate 31. As shown in Fig. 2, in the droplet ejection head 3 according to the embodiment, three driver ICs 33 are provided on each flexible substrate 31. However, the number of driver ICs 33 provided on each flexible substrate 31 is not limited to three.

[0030] 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.

[0031] 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 electrical component protection cover 40. This brings the driver IC 33 into close contact with the electrical component protection cover 40, allowing heat generated when the driver IC 33 is driven to be efficiently dissipated to the electrical component protection cover 40.

[0032] The elastic member 35 (see FIG. 4) is provided so as to contact the side wall portion 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.

[0033] 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.

[0034] The electrical component protection cover 40 is attached to the head main body 20. Specifically, the electrical component protection cover 40 is attached to the head main body 20 so as to cover the electrical component 30 located on the head main body 20, such as the flexible substrate 31, wiring substrate 32, or pressing member 34 that are drawn out from the slit portion 23b. This allows the electrical component protection cover 40 to seal the electrical component 30. The electrical component protection cover 40 is made of, for example, resin or metal.

[0035] The electrical component protection cover 40 has a rectangular cylindrical shape that opens vertically and extends longitudinally in the main scanning direction. Specifically, the electrical component protection cover 40 has a first opening 40a on its bottom surface and a second opening 40b on its top surface. The electrical component protection cover 40 also has four integral side walls 41 to 44. A third side wall 43 and a fourth side wall 44, which face each other in 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.

[0036] The first opening 40a is positioned to face the reservoir 23. The flexible substrate 31, the wiring substrate 32, and the pressing member 34 are inserted through the first opening 40a.

[0037] 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 interior of the electrical component protection cover 40. Note that the second opening 40b is not necessarily provided. The first opening 40a and the second opening 40b may be different in size.

[0038] As described above, the droplet ejection head 3 according to the first embodiment is configured such that the electrical equipment chamber 30a (flexible substrate 31) is horizontally adjacent to the reservoir flow paths 23c and 23d. Specifically, the electrical equipment chamber 30a is located between the two reservoir flow paths 23c and 23d. Therefore, if there were no space between the reservoir flow paths 23c and 23d and the electrical equipment chamber 30a, if liquid leaked from the reservoir flow paths 23c and 23d, the leaked liquid could flow between the plates of the reservoir 23 and infiltrate the electrical equipment chamber 30a. As a result, for example, the droplet ejection head 3 may not operate normally.

[0039] Therefore, the reservoir 23 of the droplet ejection head 3 according to the first embodiment is provided with a partition wall 24 having a cavity 25 between the electrical equipment chamber 30a and the reservoir flow paths 23c, 23d. As a result, even if liquid leaks from the reservoir flow paths 23c, 23d, the leaked liquid can be blocked by the cavity 25. This makes it difficult for liquid to seep into the electrical equipment chamber 30a.

[0040] The configuration of the reservoir 23 according to the first embodiment will be described below with further reference to FIGS. 5 to 7. FIG. 5 is a schematic plan view showing the configuration of the reservoir 23 according to the first embodiment. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 5. Note that for ease of understanding, the first groove portion 27 is omitted from FIG. 6.

[0041] The reservoir 23 is a member that extends long in the main scanning direction (Y-axis direction). As shown in Fig. 4, the reservoir 23 has a layered structure in which multiple reservoir plates 23A to 23H are stacked. Note that Fig. 4 shows an example of the layered structure of each of the reservoir plates 23A to 23H according to the first embodiment, and the example shown in Fig. 4 is not particularly limited. For example, the reservoir plates 23A to 23H may be configured by stacking eight or more plates.

[0042] The reservoir 23 has an opening 23a, two slits 23b, reservoir channels 23c and 23d, a partition wall 24, and a cavity 25. As described above, the opening 23a is provided on the second surface 232 of the reservoir 23, and liquid is supplied into the reservoir 23 from the opening 23a.

[0043] 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 8, if the liquid is supplied from one opening 23 a and then collected from the other opening 23 a, any air or storage liquid that was in the flow path inside the reservoir 23 can be easily removed from the flow path, making it easier to introduce the liquid into the droplet ejection head 3.

[0044] 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 8. 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.

[0045] 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 8 as a whole, some of the liquid is ejected from the ejection holes, and the liquid that is not ejected is recovered externally.

[0046] One end of the flexible substrate 31 is inserted through the two slits 23b.

[0047] The reservoir flow paths 23c and 23d are located at both ends of the reservoir 23 in the short direction, and extend along the longitudinal direction of the reservoir 23. The partition wall 24 is located between the reservoir flow paths 23c and 23d and the electrical equipment chamber 30a.

[0048] The cavity 25 is located in at least a part of the partition wall 24. The cavity 25 may penetrate the first surface 231 and the second surface 232 of the reservoir 23. In this case, the flow path member 21 may have a second groove 211 located at a position facing the cavity 25 in the main surface 21 a facing the reservoir 23.

[0049] The cavity 25 may be located outside the electrical component protection cover 40 in a plan view. Here, "outside" means being farther away from the center of the head main body 20. By locating the cavity 25 that blocks the liquid outside the electrical component protection cover 40, an operator can visually check the cavity 25. In other words, an operator can easily check whether or not liquid is leaking from the reservoir flow paths 23c, 23d.

[0050] Furthermore, when the portion of the reservoir 23 located outside the cavity 25 is defined as the first portion 233 and the portion located inside the cavity 25 is defined as the second portion 234, the reservoir 23 may further include a tab 26 connecting the first portion 233 and the second portion 234. In other words, the cavity 25 extends substantially circumferentially to surround the electrical equipment chamber 30a in a plan view, but is configured to surround only a portion of the electrical equipment chamber 30a, rather than the entire periphery. This allows the first portion 233 and the second portion 234 to be formed from a single member, thereby improving handleability. Furthermore, the cost of manufacturing the droplet ejection head 3 can be reduced compared to when the first portion 233 and the second portion 234 are formed from separate members.

[0051] The tabs 26 may be located at both longitudinal ends of the reservoir 23. In the example of FIG. 5 , the first portion 233 and the second portion 234 are connected at two locations. By connecting the first portion 233 and the second portion 234 at multiple locations, handling can be further improved. Furthermore, when the reservoir flow paths 23c and 23d extend along the longitudinal direction of the reservoir 23, the tabs 26 are located at both longitudinal ends of the reservoir 23, thereby reducing the possibility that liquid leaking from the reservoir flow paths 23c and 23d will flow into the electrical equipment chamber 30a via the tabs 26. Furthermore, the tabs 26 may be positioned so as not to be adjacent to the reservoir flow paths 23c and 23d. This further reduces the possibility that liquid leaking from the reservoir flow paths 23c and 23d will flow into the electrical equipment chamber 30a via the tabs 26.

[0052] The tab 26 may be located at the center in the short direction of the reservoir 23. With this configuration, the first portion 233 and the second portion 234 can be connected at a position away from the reservoir flow paths 23c and 23d, thereby reducing the possibility that liquid leaking from the reservoir flow paths 23c and 23d will flow into the electrical equipment chamber 30a via the tab 26.

[0053] The tab 26 may be located on the first surface 231 or the second surface 232 of the reservoir 23. In the example shown in FIG. 6, the tab 26 is located on the first surface 231 of the reservoir 23. The tab 26 is provided, for example, by half-etching the reservoir plates 23A-23H. This creates a groove between the reservoir plates 23A and 23B. Therefore, when liquid leaking from the reservoir flow path 23c flows between the reservoir plates 23A and 23B, the groove can block the liquid. This makes it difficult for liquid to penetrate into the electrical compartment 30a. Furthermore, in the example shown in FIG. 6, the tab 26 is provided at the same position in the stacking direction of the reservoir plates 23A-23H in a cross-sectional view, but this is not limiting. The tab 26 may be provided at a different position in the stacking direction of the reservoir plates 23A-23H in a cross-sectional view. In other words, the reservoir 23 may have the tabs 26 at different positions in plan view. This makes it less likely that the reservoir 23 will have locally low rigidity portions, making the reservoir 23 less likely to be damaged.

[0054] 7, the reservoir 23 may further include first grooves 27 located around the reservoir flow paths 23c and 23d. The first grooves 27 are formed by half-etching the reservoir plates 23B to 23H. With this configuration, the first grooves 27 can further block any liquid leaking from the reservoir flow paths 23c and 23d. This makes it more difficult for liquid to seep into the electrical equipment chamber 30a.

[0055] Furthermore, the depth D1 of the cavity 25 (see FIG. 4) may be greater than the depth D2 of the first groove 27 (see FIG. 7), thereby improving the possibility of blocking the liquid.

[0056] 7 shows an example in which the first groove portion 27 and the tab 26 are provided by half-etching the same surface of both main surfaces of the reservoir plates 23B to 23H, but the locations where the first groove portion 27 and the tab 26 are provided are not limited to this. For example, the first groove portion 27 and the tab 26 may be provided by half-etching different surfaces of both main surfaces of the reservoir plates 23B to 23H. The first groove portion 27 may also be provided in the reservoir plate 23A.

[0057] As described above, the reservoir 23 of the droplet ejection head 3 according to the first embodiment includes a partition wall 24 between the electrical equipment chamber 30a and the reservoir flow paths 23c and 23d, and a cavity 25 is located in at least a part of the partition wall 24. As a result, even if liquid leaks from the reservoir flow paths 23c and 23d, the leaked liquid can be blocked by the cavity 25. This makes it difficult for liquid to seep into the electrical equipment chamber 30a.

[0058] Although the configuration in which the cavity 25 penetrates the first surface 231 and the second surface 232 of the reservoir 23 has been described here, the cavity 25 does not have to penetrate the first surface 231 and the second surface 232 of the reservoir 23. For example, the cavity 25 may be open only to the second surface 232 of the reservoir 23.

[0059] Although the reservoir 23 has been described as having a laminated structure made up of multiple plates, the reservoir 23 may be a single piece. In this case, even if a crack occurs in the reservoir 23 and liquid leaks from the reservoir flow paths 23c and 23d, the leaked liquid can be blocked by the cavity 25. This makes it difficult for liquid to seep into the electrical equipment chamber 30a.

[0060] Furthermore, the cavity 25 may be present in at least a part of the partition wall 24 of the reservoir 23. As a result, even if a crack occurs in the reservoir 23 and liquid leaks from the reservoir flow paths 23c and 23d, or even if the liquid leaking from the reservoir flow paths 23c and 23d passes through gaps between the plates that form the reservoir 23, the leaked liquid can be blocked by the cavity 25.

[0061] Second Embodiment Fig. 8 is a schematic cross-sectional view showing the configuration of a droplet ejection head 3 according to a second embodiment. As shown in Fig. 8, the droplet ejection head 3 may further include a transparent member 28 that covers the opening of the cavity 25. With this configuration, the liquid blocked by the cavity 25 is less likely to spill outside the droplet ejection head 3. The transparent member 28 is, for example, a sealing resin such as an epoxy resin. A sealing resin may be provided to seal each component of the droplet ejection head 3, and this sealing resin may be provided as the transparent member 28. This allows the cavity 25 to also be blocked during the sealing process of the droplet ejection head 3.

[0062] Third Embodiment Fig. 9 is a schematic plan view showing the configuration of the reservoir 23 according to a third embodiment. In the first embodiment, the first section 233 and the second section 234 of the reservoir 23 are configured as a single member. However, the present invention is not limited to this configuration. The first section 233 and the second section 234 may be configured as separate members. In other words, the tab 26 may be omitted. In this case, as shown in Fig. 8, the cavity 25 may extend circumferentially so as to surround the electrical equipment chamber 30a in a plan view.

[0063] With this configuration, compared to when the first portion 233 and the second portion 234 are configured as a single member, liquid leaking from the reservoir flow paths 23c and 23d is less likely to infiltrate the electrical equipment chamber 30a.

[0064] The present technology may also be configured as follows. (1) A droplet ejection head (for example, the droplet ejection head 3) includes a head main body (for example, the head main body 20), a driver IC (for example, the driver IC 33), and an electrical equipment chamber (for example, the electrical equipment chamber 30a). The head main body includes a flow path member (for example, the flow path member 21) having a plurality of ejection holes, and a reservoir (for example, the reservoir 23) that is located above the flow path member and has reservoir flow paths (for example, the reservoir flow paths 23c and 23d) that are connected to the flow path member. The driver IC controls the driving of the head main body. The electrical equipment chamber houses the driver IC and is partitioned by a part of the reservoir. The reservoir includes a partition wall (for example, the partition wall 24) located between the electrical equipment chamber and the reservoir flow path, and a hollow portion (for example, the hollow portion 25) located in at least a part of the partition wall. (2) In the droplet ejection head described in (1) above, the reservoir may have a first surface (for example, the first surface 231) facing the flow path member and a second surface (for example, the second surface 232) located opposite the first surface, and the cavity may open to the second surface. (3) In the droplet ejection head described in (2) above, the cavity may extend circumferentially to surround the electrical equipment chamber in a plan view. (4) The droplet ejection head described in (2) or (3) above may further have an electrical equipment protective cover (for example, the electrical equipment protective cover 40) that covers the electrical equipment chamber, and the cavity may be located outside the electrical equipment protective cover in a plan view. (5) The droplet ejection head described in (4) above may further have a transparent member (for example, the transparent member 28) that covers the opening of the cavity. (6) In the droplet ejection head described in (1) or (2) above, the reservoir may have a first portion (for example, first portion 233) located outside the hollow portion in a planar view, a second portion (for example, second portion 234) located inside the hollow portion in a planar view, and a tab (for example, tab 26) connecting the first portion and the second portion. (7) In the droplet ejection head described in (6) above, the tab may be located at both ends of the reservoir in the longitudinal direction. (8) In the droplet ejection head described in (6) above, the tab may be located in the center of the reservoir in the lateral direction.(9) In the droplet ejection head described in any one of (6) to (8) above, the tab may be located on the first surface or the second surface of the reservoir. (10) In the droplet ejection head described in any one of (1) to (9) above, the reservoir may further include a first groove portion (for example, first groove portion 27) located around the reservoir flow path. (11) In the droplet ejection head described in (10) above, the depth of the cavity portion may be deeper than the depth of the first groove portion. (12) In the droplet ejection head described in any one of (2) to (9) above, the cavity portion may penetrate the first surface and the second surface, and the flow path member may have a second groove portion (for example, second groove portion 211) located at a position corresponding to the cavity portion in a third surface (for example, one of the main surfaces 21 a) facing the reservoir. (13) A droplet ejection device (for example, the droplet ejection device 100) may include the droplet ejection head described in any one of (1) to (12) above, and a control unit (for example, the control unit 4a) that controls the droplet ejection head. (14) A droplet ejection device may include the droplet ejection head described in any one of (1) to (12) above, an arm (for example, the robot arm 1) on which the droplet ejection head is mounted, and a control unit that controls the droplet ejection head and the arm.

[0065] The disclosed embodiments should be considered in all respects as illustrative 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 ways without departing from the scope and spirit of the appended claims.

[0066] For example, although an example has been shown in which the droplet ejection device 100 includes a robot arm 1, the present invention is not limited to this. The droplet ejection device may also be a serial printer or a line printer. That is, the droplet ejection head 3 may be one that transports a carriage, or one that is fixed to the printer. Furthermore, the droplet ejection device 100 may be used as a 3D printer or in industrial applications for printing wiring patterns.

[0067] Furthermore, although an example in which the droplet ejection head 3 applies ink or paint has been described, the present invention is not limited to this. The ejected droplets may be thermoplastic resin (filament), liquid resin, or metal paste.

[0068] 3 Droplet ejection head 20 Head body 21 Flow path member 23 Reservoir 24 Partition wall 25 Cavity 26 Tab 27 First groove 30 Electrical component section 33 Driver IC 30a Electrical component chamber 40 Electrical component protective cover 100 Droplet ejection device 233 First section 234 Second section

Claims

1. A droplet ejection head comprising: a head body having a flow path member with a plurality of ejection holes, and a reservoir located on the flow path member and having a reservoir flow path connected to the flow path member; a driver IC that controls the operation of the head body; and an electrical equipment chamber that houses the driver IC and is partitioned by a part of the reservoir, wherein the reservoir has a partition wall located between the electrical equipment chamber and the reservoir flow path, and a hollow portion located at least in a part of the partition wall.

2. A droplet ejection head as described in claim 1, wherein the reservoir has a first surface facing the flow path member and a second surface positioned opposite the first surface, and the cavity portion opens to the second surface.

3. The droplet ejection head according to claim 2, wherein the cavity extends circumferentially so as to surround the electrical equipment chamber in a plan view.

4. The droplet ejection head according to claim 2 or 3, further comprising an electrical component protection cover that covers the electrical component chamber, wherein the hollow portion is positioned outside the electrical component protection cover in a plan view.

5. The droplet ejection head according to claim 4, further comprising a transparent member covering the opening of said cavity.

6. A droplet ejection head as described in any one of claims 2 to 5, wherein the reservoir has: a first portion located outside the hollow portion in a planar view; a second portion located inside the hollow portion in a planar view; and a tab connecting the first portion and the second portion.

7. The droplet ejection head according to claim 6, wherein the tabs are located at both longitudinal ends of the reservoir.

8. The droplet ejection head according to claim 6, wherein the tab is located at the center of the reservoir in the lateral direction.

9. A droplet ejection head according to any one of claims 6 to 8, wherein the tab is located on the first surface or the second surface of the reservoir.

10. A droplet ejection head according to any one of claims 1 to 9, wherein the reservoir further comprises a first groove portion located around the reservoir flow path.

11. The droplet ejection head according to claim 10, wherein the depth of the cavity is greater than the depth of the first groove.

12. A droplet ejection head as described in any one of claims 2 to 9, wherein the cavity portion penetrates the first surface and the second surface, and the flow path member has a second groove portion located at a position corresponding to the cavity portion in the third surface facing the reservoir.

13. A droplet ejection device comprising: a droplet ejection head according to any one of claims 1 to 12; and a control unit that controls the droplet ejection head.

14. A droplet ejection device comprising: a droplet ejection head according to any one of claims 1 to 12; an arm on which said droplet ejection head is mounted; and a control unit that controls said droplet ejection head and said arm.

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