Liquid discharge head and recording device

Abstract

This liquid discharge head comprises a first substrate and a second substrate. The first substrate has a supply path that supplies a liquid. The second substrate includes a bonding layer that is bonded to the first substrate. The bonding layer has a communication path that is connected to the supply path and supplies the liquid to a nozzle. In a connection section of the supply path and the communication path, the cross-sectional area of the supply path is larger than the cross-sectional area of the communication path.

Description

Liquid dispensing head and recording device

[0001] This disclosure relates to a liquid dispensing head and a recording device.

[0002] A liquid ejection head that ejects liquid toward a recording medium is known (see, for example, Patent Document 1). In Patent Document 1, the ink supply path has at least a first flow path section, a second flow path section, and a third flow path section in order from the side closest to the common flow path along the ink supply direction, the first flow path section being a vertical flow path that allows ink supplied from the common flow path to flow upward into the second flow path section, and the third flow path section being a horizontal flow path that allows ink in the second flow path section to flow laterally out of the second flow path section.

[0003] Japanese Patent Publication No. 2011-51155

[0004] A liquid dispensing head according to one aspect of the present disclosure comprises a first substrate and a second substrate. The first substrate has a supply channel for supplying liquid. The second substrate includes a bonding layer bonded to the first substrate. The bonding layer has a connecting passage connected to the supply channel for supplying liquid to a nozzle. At the connection between the supply channel and the connecting passage, the cross-sectional area of ​​the supply channel is larger than the cross-sectional area of ​​the connecting passage.

[0005] Figure 1 is a schematic side view showing a printer according to one embodiment. Figure 2 is a schematic top view showing a printer according to one embodiment. Figure 3 is an exploded perspective view showing the schematic configuration of the liquid ejection head in steps. Figure 4 is an exploded perspective view showing the schematic configuration of the line head unit in steps. Figure 5 is a cross-sectional view along the line A-A shown in Figure 3. Figure 6 is a perspective view showing the schematic configuration of a part of the channel group in the MEMS chip. Figure 7 is a cross-sectional view showing the detailed configuration of the actuator substrate. Figure 8A is a cross-sectional view along the line B-B shown in Figure 7. Figure 8B is a diagram showing an example of a flow path according to a reference example. Figure 9 is a schematic top view showing the actuator substrate. Figure 10 is an enlarged view of region C shown in Figure 9. Figure 11 is a cross-sectional view of the support substrate, actuator substrate, and nozzle substrate of the liquid ejection head according to the first embodiment, and a top view of the support substrate. Figure 12 is a diagram showing an example of the dimensions of each part shown in Figure 11. Figure 13 is a cross-sectional view of the support substrate, actuator substrate, and nozzle substrate of the liquid ejection head according to the second embodiment, and a top view of the support substrate.

[0006] The following describes in detail, with reference to the drawings, embodiments for implementing the liquid discharge head and recording device according to this disclosure (hereinafter referred to as "Embodiments"). However, this disclosure is not limited by these embodiments. Furthermore, each embodiment can be combined as appropriate, provided that the processing content is not inconsistent. Also, the same parts are denoted by the same reference numerals in each of the following embodiments, and redundant descriptions are omitted.

[0007] Furthermore, in the embodiments described below, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not require strict adherence to "constant," "orthogonal," "perpendicular," or "parallel" conditions. In other words, each of the above expressions allows for deviations such as manufacturing accuracy or installation accuracy.

[0008] Furthermore, in the drawings referenced below, for the sake of clarity, mutually orthogonal X-axis, Y-axis, and Z-axis directions are sometimes defined, and a Cartesian coordinate system is shown with the positive Z-axis direction as the vertically upward direction.

[0009] In conventional liquid dispensing heads, the cross-sectional area of ​​the second flow path is larger than that of the first flow path at the connection point between the first and second flow paths. As a result, air bubbles tend to accumulate in the corners formed on the second flow path side at the connection point between the first and second flow paths. Therefore, there is room for improvement in conventional liquid dispensing heads in terms of air bubble discharge performance.

[0010] This disclosure provides a liquid dispensing head and a recording device capable of improving bubble discharge performance.

[0011] <Printer Configuration> First, an overview of the printer 100, which is an example of a recording device according to one embodiment, will be described with reference to Figures 1 and 2. Figure 1 is a schematic side view showing the printer 100 according to one embodiment. Figure 2 is a schematic top view showing the printer 100 according to one embodiment. The printer 100 according to one embodiment is, for example, a color inkjet printer.

[0012] As shown in Figure 1, the printer 100 includes a paper feed roller 101, guide rollers 102A to 102C, multiple transport rollers 103, a recovery roller 104, a head case 105, multiple frames 106, multiple liquid discharge heads 1, a dryer 107, and a coating machine 109. Furthermore, the printer 100 includes a sensor unit 108 and a control unit 200.

[0013] The control unit 200 controls the paper feed roller 101, guide rollers 102A to 102C, multiple transport rollers 103, recovery roller 104, head case 105, multiple frames 106, multiple liquid discharge heads 1, dryer 107, sensor unit 108, and coating machine 109.

[0014] The printer 100 records images or characters on the printing paper P by depositing droplets of liquid onto the paper P. The printing paper P is an example of a recording medium. Before use, the printing paper P is wound around the paper feed roller 101. The printer 100 then transports the printing paper P from the paper feed roller 101 to the inside of the head case 105 via the guide roller 102A and the coating machine 109.

[0015] The coating machine 109 uniformly applies the coating agent to the printing paper P. This allows the printing paper P to undergo surface treatment, thereby improving the print quality of the printer 100.

[0016] The head case 105 houses multiple transport rollers 103, multiple frames 106, and multiple liquid discharge heads 1. Inside the head case 105, a space is formed that is isolated from the outside, except for parts that are connected to the outside, such as the area where the printing paper P enters and exits.

[0017] The internal space of the head case 105 is controlled by the control unit 200, as needed, by at least one of the control factors such as temperature, humidity, and atmospheric pressure. The transport roller 103 transports the printing paper P to the vicinity of the liquid discharge head 1 inside the head case 105.

[0018] The frame 106 is a rectangular flat plate and is positioned close above the printing paper P being transported by the transport roller 103. Also, as shown in Figure 2, the frame 106 is positioned so that its longitudinal direction is perpendicular to the transport direction of the printing paper P. Inside the head case 105, multiple (for example, four) frames 106 are positioned along the transport direction of the printing paper P.

[0019] Liquid, such as ink, is supplied to the liquid ejection head 1 from a liquid tank (not shown). The liquid ejection head 1 ejects droplets supplied from the liquid tank.

[0020] The control unit 200 controls the liquid ejection head 1 based on data such as images or characters, and ejects droplets toward the printing paper P. The distance between the liquid ejection head 1 and the printing paper P is, for example, about 0.5 to 20 mm.

[0021] The liquid dispensing head 1 is fixed to the frame 106. The liquid dispensing head 1 is fixed to the frame 106, for example, at both ends in the longitudinal direction. The liquid dispensing head 1 is positioned so that its longitudinal direction is perpendicular to the transport direction of the printing paper P.

[0022] In other words, the printer 100 according to one embodiment is a so-called line printer in which a liquid ejection head 1 is fixed inside the printer 100. However, the printer 100 according to one embodiment is not limited to a line printer, but may also be a so-called serial printer. A serial printer is a printer that alternately performs the operation of recording while moving the liquid ejection head 1 back and forth in a direction intersecting the transport direction of the printing paper P, for example, in a nearly perpendicular direction, and the transport of the printing paper P.

[0023] As shown in Figure 2, a unit formed by arranging multiple (for example, eight) liquid discharge heads 1 on a single frame 106 is also called a Line Head Unit (LHU). Figure 2 shows an example of a Line Head Unit 1A in which four liquid discharge heads 1 are positioned in a staggered pattern in front of the printing paper P in the transport direction, and four are positioned behind it. The liquid discharge heads 1 are positioned so that the centers of each liquid discharge head 1 do not overlap in the transport direction of the printing paper P.

[0024] The line head unit 1A is composed of multiple liquid ejection heads 1 located on a single frame 106. The four line head units 1A are positioned along the transport direction of the printing paper P. Liquid ejection heads 1 belonging to the same line head unit 1A are supplied with ink of the same color. As a result, the printer 100 can perform printing with four colors of ink using the four line head units 1A. The four line head units 1A may be arranged side by side to form a carriage, which is one example of the final form of the liquid ejection head 1.

[0025] The ink colors ejected from each line head unit 1A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The control unit 200 controls each line head unit 1A to eject multiple colors of ink onto the printing paper P, thereby enabling the printing of a color image on the paper P.

[0026] Furthermore, in order to treat the surface of the printing paper P, a coating agent may be dispensed onto the printing paper P from the liquid discharge head 1.

[0027] Furthermore, the number of liquid ejection heads 1 included in one line head unit 1A, or the number of line head units 1A installed in the printer 100, can be appropriately changed depending on the object to be printed or the printing conditions. For example, if the color to be printed on the printing paper P is a single color and the printing is limited to the area that can be printed with one liquid ejection head 1, then the number of liquid ejection heads 1 installed in the printer 100 may be as small as one.

[0028] The printed paper P, which has been processed inside the head case 105, is transported to the outside of the head case 105 by the transport roller 103, then transported by the guide roller 102B, and passes through the inside of the dryer 107. The dryer 107 dries the printed paper P. The printed paper P that has been dried in the dryer 107 is transported by the guide roller 102C and collected by the recovery roller 104.

[0029] In the printer 100, drying the printing paper P in the dryer 107 reduces the likelihood of the overlapping printing paper P sticking together or of undried liquid rubbing against each other in the recovery roller 104.

[0030] The sensor unit 108 is composed of a position sensor, a speed sensor, or a temperature sensor, etc. Based on the information from the sensor unit 108, the control unit 200 can determine the state of each part of the printer 100 and control each part of the printer 100.

[0031] The printer 100 described so far has shown the case where printing paper P is used as the printing target (i.e., recording medium), but the printing target in the printer 100 is not limited to printing paper P. For example, the printing target may be a roll of cloth or the like.

[0032] Alternatively, the printer 100 may transport the printing paper P on a conveyor belt instead of directly transporting it. By using a conveyor belt, the printer 100 can print on sheets of paper, cut cloth, wood, tiles, etc.

[0033] The printer 100 may also print wiring patterns for electronic devices by ejecting droplets containing conductive particles from the liquid ejection head 1. Alternatively, the printer 100 may produce chemical products by ejecting a predetermined amount of liquid chemical agent or droplets containing a chemical agent from the liquid ejection head 1 toward a reaction vessel or the like.

[0034] The printer 100 may also include a cleaning unit for cleaning the liquid ejection head 1. The cleaning unit cleans the liquid ejection head 1, for example, by wiping or capping.

[0035] Wiping is a process that removes liquid adhering to the liquid discharge head 1 by wiping the surface of the area where the liquid droplets are discharged with a flexible wiper, for example.

[0036] Furthermore, the capping process is carried out, for example, as follows: First, a cap is placed over the surface of the area from which the droplets are dispensed (this is called capping). This creates a nearly sealed space between the surface of the area from which the droplets are dispensed and the cap.

[0037] Next, the droplets are repeatedly dispensed within this sealed space. This removes any liquid or foreign matter with a higher viscosity than standard that may have clogged the nozzle from which the droplets are dispensed.

[0038] <Configuration of the liquid ejection head in the line head unit> Next, the configuration of the liquid ejection head 1 and the line head unit 1A according to an embodiment will be described with reference to FIGS. 3 to 6. FIG. 3 is an exploded perspective view showing the schematic configuration of the liquid ejection head 1 step by step. FIG. 4 is an exploded perspective view showing the schematic configuration of the line head unit 1A step by step. FIG. 5 is a cross-sectional view taken along the line A-A shown in FIG. 3. FIG. 6 is a perspective view showing a schematic configuration of a part of the channel group in the MEMS chip 10.

[0039] The liquid ejection head 1 is assembled in the order of FIGS. 3(a) to 3(c). The line head unit 1A is assembled in the order of FIGS. 4(a) and 4(b) using eight liquid ejection heads 1 shown in FIG. 3(c). As shown in FIG. 3(a), the liquid ejection head 1 includes a MEMS (Micro Electro Mechanical Systems) chip 10 and a COF substrate (Chip on Film) 11 on a film. One end of the MEMS chip 10 is adhered to one end of the COF substrate 11. As a result, as shown in FIG. 3(b), a terminal 143 (see FIG. 5) disposed at one end of the MEMS chip 10 and wiring (not shown) in the COF substrate 11 are connected, so that the MEMS chip 10 is electrically connected to the COF substrate 11. Note that the MEMS chip 10 can also be referred to as a discharge chip or an individual flow path member.

[0040] The COF substrate 11 mounts a drive IC 111. The drive IC 111 can communicate with the control unit 200 wirelessly or by wire. Therefore, the drive IC 111 generates a drive signal based on the control signal transmitted from the control unit 200. Then, the drive IC 111 outputs the drive signal to an actuator substrate 3, which will be described later, in the MEMS chip 10 via the COF substrate 11. Thereby, the drive IC 111 can control the driving of the liquid ejection head 1.

[0041] Further, as shown in FIG. 3(b), the liquid ejection head 1 includes a manifold member 12. The constituent material of the manifold member 12 may be metal or resin.

[0042] The manifold member 12 may have a layered structure of multiple plates, or it may be a single plate. Each plate has a base portion 12a and a projection portion 12b. The projection portion 12b is the part that protrudes from the central region when the base portion 12a is divided into three parts in the longitudinal direction. The longitudinal direction of the base portion 12a is longer than the longitudinal direction of the MEMS chip 10. The manifold member 12 is joined to the MEMS chip 10 such that the base portion 12a is positioned on top of the MEMS chip 10. This constitutes an ultra-compact integrated module called a so-called front-end module (FEM), as shown in Figure 3(c).

[0043] As an example of the layered structure of the manifold member 12, referring to Figure 5, which shows a cross-section along line A-A in Figure 3(c), the manifold member 12 has a structure in which the top layer plate 121a, the middle layer plate 121b, and the bottom layer plate 121c are stacked from top to bottom. The top layer plate 121a has a filter 121f. The upper part of the filter 121f is connected to the reservoir flow path of the reservoir member 14 (see Figure 4(b)). The filter 121f is located at the protruding portion 12b and filters out impurities from the liquid in the reservoir flow path. The top layer plate 121a has a flow path 121 through which the filtered liquid flows. The bottom layer plate 121c has a common flow path 123 along the longitudinal direction of the base portion 12a. The intermediate plate 121b is located between the uppermost plate 121a and the lowermost plate 121c, and has a hole 122 that connects the flow path 121 of the uppermost plate 121a with the common flow path 123.

[0044] As shown in Figure 4(a), eight front-end modules (FEMs) are arranged in a staggered pattern, and eight manifold members 12 are joined together in a line. This positions eight common flow paths 123 above the eight MEMS chips 10. Also, as shown in Figure 4(b), a nozzle cover 13 is joined below the eight MEMS chips 10, covering the eight MEMS chips 10. This covers and protects the eight MEMS chips 10. The longitudinal length of the nozzle cover 13 is longer than the length of the eight manifold members 12. The nozzle cover 13 has eight rectangular openings 133. The openings 133 are positioned to correspond to the eight nozzles 41 (see Figure 5) of the eight MEMS chips 10, allowing liquid to be discharged from the eight nozzles 41.

[0045] Furthermore, the liquid discharge head 1 has a reservoir member 14 with a reservoir channel (not shown) inside. The longitudinal direction of the reservoir member 14 is longer than the length of the eight manifold members 12 on the line and is approximately equal to the length of the nozzle cover 13. The reservoir member 14 is joined to the eight manifold members 12 so as to be located above the eight manifold members 12. As a result, the reservoir channel is located on the common channel 123 of the eight manifold members 12.

[0046] The reservoir member 14 is an injection-molded product made of resin. Here, "made of resin" means that it is made of resin, and includes products that are mainly composed of resin and contain small amounts of impurities. The reservoir member 14 supplies liquid by dividing it from the reservoir channel to eight common channels 123.

[0047] Liquid supply ports 15 and liquid discharge ports 16 are located at both ends of the reservoir member 14 in the Y-axis direction. Liquid is supplied from the liquid supply ports 15 to the reservoir flow path within the reservoir member 14. The liquid discharge head 1 temporarily stores the liquid supplied to the reservoir member 14 in the reservoir flow path, supplies it to eight common flow paths 123 that branch off from the reservoir flow path, and discharges it from the nozzle 41 through the flow path in the MEMS chip 10 located below each common flow path 123. The liquid discharge head 1 discharges any liquid that was not supplied from the reservoir flow path of the reservoir member 14 to each common flow path 123 from the liquid discharge ports 16.

[0048] Furthermore, the liquid ejection head 1 may collect liquid from the liquid outlet 16 while printing is in progress. Doing so makes it less likely for air bubbles to accumulate in the reservoir flow path within the reservoir member 14. In addition, the temperature of the liquid ejection head 1 can be stabilized by supplying liquid adjusted to a constant temperature. The collected liquid may be passed through a filter or the like and then supplied back to the liquid ejection head 1. In other words, the liquid ejection head 1 may circulate the liquid. The supply and collection of liquid to and from the liquid ejection head 1, or the circulation of liquid, may be controlled by the control unit 200.

[0049] The above description shows an example of the configuration of the liquid discharge head 1. The configuration in Figure 4(b) may further include a circuit board, a heat sink for dissipating heat generated by the circuit board, cover members for the circuit board and heat sink, etc. For convenience, descriptions of these components have been omitted.

[0050] <Channel Group> The thickness direction of the MEMS chip 10 is defined as the Z-axis direction, and the positive Z-axis direction is defined as the vertically upward direction. The longitudinal direction (Y-axis direction) of the MEMS chip 10 is also called the row direction, and the short direction (X-axis direction) of the MEMS chip 10 is also called the column direction. In the example in Figure 5, the MEMS chips 10 located on both sides of line O show cross-sections of two channels arranged symmetrically with respect to line O.

[0051] A channel refers to a single unit configuration that includes a flow path extending from the supply path 51 through the connecting passage 52 and the liquid chamber 131 to the nozzle 41, an actuator 30, and a diaphragm 38. A group of channels consisting of 100 to 2000 channels in the row direction and two groups arranged in the column direction is called a channel group 10a, 10b. Channel groups 10a and 10b are arranged symmetrically with respect to line O shown in Figure 5. However, the number of channel groups can be changed as appropriate.

[0052] The MEMS chip 10 has a substrate in which a support substrate 2, an actuator substrate 3, and a nozzle substrate 4 are stacked from top to bottom. However, the three substrates, the support substrate 2, the actuator substrate 3, and the nozzle substrate 4, may be integrated into a single unit. Alternatively, only the two substrates, the actuator substrate 3 and the nozzle substrate 4, may be integrated into a single unit.

[0053] The support substrate 2 has a supply passage 51. The actuator substrate 3 has a bonding layer 3a and a liquid chamber substrate 3b stacked from top to bottom. The bonding layer 3a has a communication passage 52, an actuator 30, and a diaphragm 38. The diaphragm 38 is positioned on the lower surface of the actuator 30. The area around the actuator 30 is covered by a space 132, except for the lower surface. The liquid chamber substrate 3b has a liquid chamber 131. The nozzle substrate 4 has nozzles 41 for discharging liquid. The liquid chambers 131 are arranged in rows of 100 to 2000 units and in columns of 2 units, for a total of 200 to 4000 units. Corresponding to the liquid chambers 131, there are 100 to 2000 nozzles 41 in the row direction and 2 units in the column direction, for a total of 200 to 4000 nozzles 41, and the same number of supply passages 51 and communication passages 52 as there are nozzles 41. In this configuration, the supply passages 51, connecting passages 52, liquid chambers 131, and nozzles 41, arranged in two rows of 100 to 2000 each along the row direction according to this embodiment, form channel groups 10a and 10b. The common flow path 123 is a common flow path for 200 to 4000 channels and is connected to the 200 to 4000 supply passages 51, which are arranged in two rows of 100 to 2000 each, and supplies liquid to the 200 to 4000 nozzles 41. In the plan view of the actuator substrate 3 shown in Figure 9, parts of the channel groups 10a and 10b, which are arranged in two rows in the row direction, are shown within the frames, respectively.

[0054] The bottommost plate 121c is located on the support substrate 2. The upper surface of the support substrate 2 constitutes the bottom of the common channel 123. However, the bottommost plate 121c may have a bottom and the common channel 123 may be located inside it. In this case, a hole communicating with the supply passage 51 may be provided in the bottom of the bottommost plate 121c. The supply passage 51 penetrates the support substrate 2 in the Z-axis direction. The support substrate 2 is an example of a first substrate having a supply passage for supplying liquid.

[0055] The bonding layer 3a is bonded to the support substrate 2. The communication passage 52 penetrates the bonding layer 3a and is connected to the supply passage 51. The actuator substrate 3 is an example of a second substrate that includes a bonding layer 3a bonded to the first substrate, and the bonding layer 3a is connected to the supply passage 51 and has a communication passage 52 that supplies liquid to the nozzle 41.

[0056] The liquid chamber 131 is located below the actuator 30 and is connected to the communication passage 52, which communicates the communication passage 52 with the nozzle 41. The liquid chamber 131 is a space enclosed by the diaphragm 38, the upper surface of the nozzle substrate 4, and the solid 39, and extends from below the communication passage 52 to above the nozzle 41.

[0057] Figure 6 is a perspective view showing a schematic configuration of a part of channel group 10a, with channel group 10b omitted. As shown in Figure 6, the actuator substrate 3 can be electrically connected to the outside through terminal 143 by electrical junctions 141 and 142 located at one end of channel group 10a. One end of channel group 10a is located on the opposite side of channel group 10b.

[0058] <Configuration of Actuator Substrate> The detailed configuration of the actuator substrate 3 will be described with reference to Figures 7 to 9. Figure 7 is a cross-sectional view showing the detailed configuration of the actuator substrate 3. Figure 8A is a cross-sectional view along the line B-B shown in Figure 7. Figure 8B is a diagram showing an example of a flow path according to a reference example. Figure 9 is a schematic plan view showing the actuator substrate 3. Note that Figure 7 shows the configuration of channel group 10a, and the configuration of channel group 10b is omitted. Since the configuration of channel group 10a and the configuration of channel group 10b are the same, the explanation of the configuration of channel group 10b is omitted.

[0059] The thickness (length in the Z-axis direction) of the support substrate 2 is, for example, 200 to 400 μm. The thickness (length in the Z-axis direction) of the actuator substrate 3 is, for example, 30 to 75 μm. The thickness (length in the Z-axis direction) of the nozzle substrate 4 is, for example, 75 to 150 μm. In Figure 7, for convenience, the thickness of the actuator substrate 3 is shown to be greater than the thickness of the nozzle substrate 4, but in reality, the thickness of the nozzle substrate 4 may be greater than the thickness of the actuator substrate 3. The constituent materials of the support substrate 2, liquid chamber substrate 3b, and nozzle substrate 4 may be Si.

[0060] The bonding layer 3a has a bonding film 31, an actuator 30, and a diaphragm 38. The bonding film 31 is bonded to the support substrate 2 on the upper surface of the bonding layer 3a. The communication passage 52 penetrates the bonding film 31, and the side surface of the communication passage 52 is the SiO of the bonding film 31. ２ The bonding film 31 is formed of Si. The bonding film 31 may be Si. The communication passage 52 is located below the supply passage 51 and communicates with the supply passage 51. The bonding of the support substrate 2 and the bonding film 31 may be done by room temperature direct bonding using intermolecular forces, adhesive bonding, or gold-gold bonding. The bonding of the liquid chamber substrate 3b and the nozzle substrate 4 may also be done by room temperature direct bonding. Since the liquid chamber substrate 3b and the nozzle substrate 4 are formed from the same constituent material, they are easy to bond, and other bonding methods may be used.

[0061] The liquid chamber 131 is located below the communication passage 52 and communicates with the communication passage 52. The liquid chamber 131 has an inlet channel 53. The inlet channel 53 is the connection point of the liquid chamber 131 that communicates with the communication passage 52 at the connection point between the communication passage 52 and the liquid chamber 131. The connection point between the communication passage 52 and the liquid chamber 131 is the part where the bonding layer 3a and the liquid chamber substrate 3b are connected at the boundary between the bonding layer 3a and the liquid chamber substrate 3b. As a result, the bonding layer 3a and the liquid chamber substrate 3b communicate with each other.

[0062] The liquid chamber 131 is connected to the communication passage 52 by an inlet flow path 53 and extends below the actuator 30 on the positive X-axis side. Furthermore, there is a one-to-one correspondence between the liquid chamber 131 of each channel and the actuator 30, forming a single hollow region 3A within the actuator substrate 3. Liquid is stored within the liquid chamber 131. Each channel's liquid chamber 131 corresponds one-to-one with the supply passage 51, the communication passage 52, and the nozzle 41, and liquid is supplied from the common flow path 123 of the manifold member 12. The common flow path 123 supplies liquid to 200 to 4000 channels.

[0063] The thickness of the bonding layer 3a may be several μm to 20 μm. The thickness of the liquid chamber substrate 3b may be 30 to 75 μm. Examples of constituent materials for the liquid chamber substrate 3b include Si.

[0064] For example, the depth (length in the Z-axis direction) of the supply passage 51 is equal to the thickness of the support substrate 2 and may be 200 to 400 μm. The depth (length in the Z-axis direction) of the communication passage 52 is equal to the length from the upper surface of the bonding film 31 to the lower surface of the diaphragm 38, i.e., the thickness of the bonding layer 3a and may be several μm to 20 μm. The depth (length in the Z-axis direction) of the liquid chamber 131 is equal to the thickness of the liquid chamber substrate 3b and may be 30 to 75 μm.

[0065] The solid core 39 is located around each hollow region 3A between the diaphragm 38 and the nozzle substrate 4, and has the function of separating each hollow region 3A from other hollow regions 3A. Examples of materials that make up the solid core 39 include silicon.

[0066] The diaphragm 38 is provided on the liquid chamber 131 and on the solid 39. The diaphragm 38 has openings in parts corresponding to each liquid chamber 131. Liquid is supplied to the liquid chamber 131 from the common channel 123 through these openings. The openings in the diaphragm 38 constitute part of the communication passage 52.

[0067] The thickness of the diaphragm 38 may be, for example, 1 μm or more and 10 μm or less. The diaphragm 38 in this embodiment is a single layer, but is not limited to this. For example, the diaphragm 38 may have a multilayer structure. Also, the diaphragm 38 may have a multilayer structure locally, for example, only on the solid 39. That is, the thickness of the diaphragm 38 on the solid 39 may be thicker than the thickness of the diaphragm 38 on the liquid chamber 131. Examples of constituent materials for the diaphragm 38 are Si, SiO ２ These are some examples.

[0068] The actuator 30 is provided on a diaphragm 38 corresponding to the liquid chamber 131. The actuator 30 has a common electrode 35, a piezoelectric element 36, and individual electrodes 37. The actuator 30 is provided in a one-to-one relationship with the liquid chamber 131. The actuator 30 has the common electrode 35 located on the diaphragm 38 corresponding to the liquid chamber 131, the piezoelectric element 36 located on the common electrode 35, and the individual electrodes 37 located on the piezoelectric element 36, but is not limited to this configuration. For example, the individual electrodes 37, piezoelectric element 36, and common electrode 35 may be provided on the diaphragm 38 in that order.

[0069] In the plan view of the actuator substrate 3 shown in Figure 9, the common electrode 35 is provided across the actuators 30 of multiple channels in each channel group 10a, 10b, but is not limited to this. For example, the common electrode 35 may be provided individually corresponding to each actuator 30 of each channel. The thickness of the common electrode 35 may be, for example, 0.1 to 1 μm. The constituent material of the common electrode 35 may be, for example, a metallic material such as Pt.

[0070] The piezoelectric elements 36 are individually provided corresponding to each liquid chamber 131, but are not limited to this arrangement. For example, the piezoelectric elements 36 may be provided across multiple channels of liquid chambers 131 in a plan view of the actuator substrate 3. In the piezoelectric element 36, the portion sandwiched between the individual electrodes 37 and the common electrode 35 is polarized in the thickness direction along the Z-axis. Therefore, for example, when a voltage is applied in the polarization direction of the piezoelectric element 36 by the individual electrodes 37 and the common electrode 35, the piezoelectric element 36 contracts in the direction along the diaphragm 38. This contraction causes the piezoelectric element 36 to displace so that it becomes convex toward the liquid chamber 131. Along with the displacement of the piezoelectric element 36, the diaphragm 38 located on the liquid chamber 131 also displaces. As a result, pressure is applied to the liquid in the liquid chamber 131. This causes the liquid to be discharged from the liquid chamber 131 through the nozzle 41.

[0071] The thickness of the piezoelectric element 36 may be 1 μm or more and 10 μm or less. The constituent material of the piezoelectric element 36 is, for example, Pb(Zr,Ti)O ３ System, NaNbo ３ system, BaTiO ３ System, (BiNa)NboO ３ System, BiNaNB ５ O １５ Examples include ferroelectric ceramic constituent materials such as those found in systems.

[0072] Individual electrodes 37 are provided individually, corresponding to each liquid chamber 131. The thickness of the individual electrodes 37 may be 0.05 μm or more and 1 μm or less. The constituent material of the individual electrodes 37 may be a metallic material such as Pt.

[0073] The electrical junctions 141 and 142 shown in Figures 6 and 9 are located on the X-axis end of the actuator substrate 3. The tips of the electrical junctions 141 and 142 are connected to a plurality of terminals 143. The plurality of terminals 143 are electrically connected to the actuator substrate 3.

[0074] As shown in FIG. 7, the bonding layer 3a has a diaphragm 38 positioned on the liquid chamber substrate 3b, an actuator 30 positioned on the diaphragm 38, an insulating film 33, and a bonding film 31. The insulating film 33 is positioned on at least a part of the actuator 30. The bonding film 31 is positioned on at least a part of the insulating film 33. The insulating film 33 is provided on the actuator 30 to prevent a short circuit between the actuators 30 of each channel and the actuators 30 of other channels or wirings such as the lead-out wiring 144.

[0075] The bonding film 31 is positioned under the support substrate 2 and bonds the support substrate 2 and the bonding layer 3a. The thickness of the bonding film 31 may be, for example, several μm to 20 μm. Also, examples of the constituent material of the bonding film 31 include materials such as SiO ２ and the like.

[0076] In addition to FIG. 7, referring to FIG. 8A showing a cross-section along the line B-B shown in FIG. 7, the bonding layer 3a has, in addition to the bonding film 3, a protective layer 32, an insulating film 33, and an adhesion layer 34. Under the bonding film 31, a protective layer 32, an insulating film 33, an adhesion layer 34, and a common electrode 35 are laminated in this order from above. The thickness of the protective layer 32 may be, for example, 0.1 to 1 μm. Also, examples of the constituent material of the protective layer 32 include materials such as SiN.

[0077] The thickness of the insulating film 33 may be, for example, 0.1 to 1 μm. Also, examples of the constituent material of the insulating film 33 include materials such as SiO ２ and the like. The thickness of the adhesion layer 34 may be, for example, 0.01 to 0.1 μm. Also, examples of the constituent material of the adhesion layer 34 include materials such as SiN.

[0078] Note that an adhesion layer not shown may be provided between the common electrode 35 and the piezoelectric body 36 or between the piezoelectric body 36 and the individual electrode 37.

[0079] The protective layer 32 and the insulating film 33 are positioned on at least a part of the actuator 30. The upper surface of the actuator 30 is exposed to the space 132 except for the outer periphery of the actuator 30.

[0080] The lead wires 144 are electrically connected to the individual electrodes 37 and are wires that extend from each individual electrode 37. In the example shown in Figure 7, the lead wires 144 are positioned between the protective layer 32 and the insulating film 33 and extend from the portion corresponding to the liquid chamber 131 to the portion corresponding to the solid 39. The thickness of the lead wires 144 may be, for example, 0.1 μm or more and 1 μm or less. The constituent material of the lead wires 144 may be, for example, Au.

[0081] The protective layer 32 protects the actuator 30 beneath the bonding film 31. The insulating film 33 is provided on the diaphragm 38 to cover the lead wiring 144 in order to reduce the possibility of corrosion of the lead wiring 144. The insulating film 33 is in close contact with the diaphragm 38, which generally corresponds to the solid 39 excluding the liquid chamber 131.

[0082] The bonding film 31, protective layer 32, insulating film 33, adhesion layer 34, common electrode 35, individual electrode 37, and lead wiring 144 according to this embodiment may be formed on each layer using the CVD method. By using the CVD method, the step coverage is improved, so the coverage of each layer and lead wiring 144 is improved, and the possibility of corrosion of each layer and lead wiring 144 can be further reduced. However, each layer and lead wiring 144 according to this embodiment may be formed using the sputtering method, not limited to the CVD method. By using the sputtering method, particles that will become the constituent material of each layer and lead wiring 144 will adhere to the surface. Therefore, the adhesion between each layer and the diaphragm 38 and lead wiring 144 can be improved.

[0083] The wiring of the actuator substrate 3 according to this embodiment will be further described with reference to Figure 9. In a plan view, the actuator substrate 3 shown in Figure 9 shows a portion of the channel groups 10a and 10b arranged in two rows. 100 to 2000 lead wires 144 are drawn out from the individual electrodes 37 of each channel in the channel groups 10a and 10b.

[0084] The number of lead wires 144 on each channel group 10a, 10b may be set as appropriate. Each lead wire 144, when viewed from above, is connected to an individual electrode 37 corresponding to the liquid chamber 131 and is led out in the positive X-axis direction. The lead wire 144 led out from channel group 10b is connected to an electrical junction 142. The electrical junction 142 runs along the positive X-axis direction within the region of channel group 10a and is electrically connected to a terminal 143 of an individual terminal region 201 formed in the positive X-axis direction of channel group 10a. The lead wire 144 led out from channel group 10a in the positive X-axis direction is connected to an electrical junction 141. The electrical junction 141 runs along the positive X-axis direction and is electrically connected to a terminal 143 of an individual terminal region 201.

[0085] Therefore, each actuator 30 of channel groups 10a and 10b receives a drive signal from the drive IC 111 on the COF substrate 11 via terminals 143 through electrical junctions 141 and 142. Each individual electrode 37 of each actuator 30 is supplied with an individual drive potential via lead wiring 144 based on the drive signal (see Figure 5).

[0086] With this configuration, each actuator 30 of channel groups 10a and 10b receives a drive signal corresponding to a desired control signal from the control unit 200 (Figure 9(1)), and displaces the piezoelectric element 36 so that it protrudes toward the liquid chamber 131 according to the drive signal. As the piezoelectric element 36 is displaced, the diaphragm 38 located on the liquid chamber 131 is displaced, and pressure is applied to the liquid in the liquid chamber 131. As a result, liquid is discharged from each liquid chamber 131 through each nozzle 41. This causes the drive IC 111 to drive the liquid discharge head 1.

[0087] The common electrode 35 is electrically connected to the ground connection 145 of the ground region 202 via a common wiring 146 (Figure 9(2)). As a result, the common electrode 35 is supplied with ground potential. Ground potential means 0V. Note that the common wiring 146 is not shown in Figures 5 to 7.

[0088] <Configuration of supply path, connecting passage and liquid chamber> Next, the configuration of the supply path 51, connecting passage 52 and liquid chamber 131 (inlet flow path 53) will be explained with reference to Figures 7, 8A, 8B, and 10 to 12. Figure 8A is a cross-sectional view along the line B-B shown in Figure 7, and is a diagram for explaining the relationship between the shape of the supply path 51, connecting passage 52 and liquid chamber 131 and the bubble discharge performance. Figure 8B is a diagram showing an example of a reference example for explaining the relationship between the shape of the flow path and the bubble discharge performance. Figure 10 is an enlarged view of region C shown in Figure 9. Figures 11 and 12 are cross-sectional views of the support substrate 2, actuator substrate 3, nozzle substrate 4 and a plan view of the liquid chamber 131.

[0089] The supply channel 51 and the connecting passage 52 are flow channels with a cross-section that is circular, elliptical, or other shape. As shown in Figure 8A, for example, the maximum width L1 of the supply channel 51 is 45 to 49 μm, and the maximum width L2 of the connecting passage 52 is 35 to 45 μm.

[0090] At the connection point between the supply passage 51 and the communication passage 52, the cross-sectional area of ​​the supply passage 51 (flow path cross-sectional area) is larger than the cross-sectional area of ​​the communication passage 52 (flow path cross-sectional area). The connection point between the supply passage 51 and the communication passage 52 is the part where the supply passage 51 and the communication passage 52 are connected at the boundary between the support substrate 2 and the bonding film 31. This allows the supply passage 51 and the communication passage 52 to communicate. The cross-sectional area of ​​the supply passage 51 is the area of ​​the cross-section obtained by cutting the supply passage 51 in a direction perpendicular to the direction in which the liquid flows through the supply passage 51 (for example, the Z direction) at the connection point where the supply passage 51 connects to the communication passage 52. The cross-sectional area of ​​the communication passage 52 is the area of ​​the cross-section obtained by cutting the communication passage 52 in a direction perpendicular to the direction in which the liquid flows through the communication passage 52 (for example, the Z direction) at the connection point where the communication passage 52 connects to the supply passage 51.

[0091] In the example shown in Figure 8B, at the connection point between channel 91 and channel 92, the cross-sectional area of ​​channel 91 is smaller than that of channel 92. Therefore, when liquid flows from channel 91 to channel 92, the flow velocity of the liquid decreases at the connection point P9 between channel 91 and channel 92. As a result, the liquid has difficulty flowing at the corners of channel 92, and bubbles tend to accumulate at the corners of the connection point P9. This makes it difficult for bubbles to be discharged from channel 92, increasing the likelihood of bubbles remaining in channel 92.

[0092] In contrast, in the liquid discharge head 1 of this embodiment, as shown in Figure 8A, at the connection point P1 between the supply passage 51 and the connecting passage 52, the cross-sectional area of ​​the supply passage 51 is larger than the cross-sectional area of ​​the connecting passage 52. At the connection point P1, the outer peripheral end of the upper surface of the bonding membrane 31 is located inward from the side surface of the supply passage 51. When liquid flows from the supply passage 51 to the connecting passage 52, the flow velocity of the liquid increases at the connection point P1. Therefore, liquid flows more easily at the connection point P1 than at the connection point P9, and areas where the liquid flow velocity slows down, such as the corner of the connection point P9 shown in Figure 8B, are eliminated or reduced. As a result, the liquid discharge head 1 can reduce the possibility of air bubbles remaining at the connection point P1 and improve air bubble discharge performance. As a result, the liquid discharge head 1 can reduce, for example, deterioration of the liquid discharge characteristics. Furthermore, even if air bubbles remain in the connection part P1, the liquid discharge head 1 can easily discharge the liquid from the supply path 51 and the communication passage 52 during purging, such as between prints or when the user returns due to a printing defect.

[0093] Furthermore, as shown in Figure 10, which is an enlarged view of region C shown in Figure 9, in a plan view of the actuator substrate 3, the outer edge of the supply passage 51 at the connection point between the supply passage 51 and the communication passage 52 may include the entire outer edge of the communication passage 52. This increases the liquid flow velocity at the connection point between the supply passage 51 and the communication passage 52. As a result, regions where the liquid flow velocity is slow, such as the corner of the connection point P9 shown in Figure 8B, are eliminated or reduced. This allows the liquid discharge head 1 to reduce the possibility of bubbles remaining at the connection point between the supply passage 51 and the communication passage 52 and improve bubble discharge performance.

[0094] Furthermore, as shown in Figure 8A, at the connection point P2 between the communication passage 52 and the liquid chamber 131, the maximum width L3 of the liquid chamber 131 (inlet channel 53) in the width direction of the liquid chamber 131 is 30 to 35 μm. The inlet channel 53 is the part of the liquid chamber 131 that connects to the communication passage 52 at the connection point P2 between the communication passage 52 and the liquid chamber 131, and is a part of the liquid chamber 131. As mentioned above, in a plan view, the maximum width L2 of the communication passage 52 in the width direction of the liquid chamber 131 is 35 to 45 μm. Therefore, as shown in Figure 10, in a plan view, at the connection point between the communication passage 52 and the liquid chamber 131, the maximum width L2 of the communication passage 52 in the width direction (for example, the Y-axis direction) of the liquid chamber 131 may be greater than the maximum width L3 of the liquid chamber 131 (inlet channel 53).

[0095] As a result, at the connection point P2 between the communication passage 52 and the liquid chamber 131, the outer peripheral end of the upper surface of the liquid chamber substrate 3b protrudes inward from the side surface of the communication passage 52. This allows the liquid discharge head 1 to eliminate or reduce the area at the corner where the liquid flow velocity slows down, even at the connection point P2 between the communication passage 52 and the liquid chamber 131.

[0096] Furthermore, as shown in Figure 10, in a plan view, in a direction perpendicular to the width direction (for example, the X-axis direction) and in a direction where the nozzle 41 is not located (negative X-axis direction: see Figure 9), the outer edge of the communication passage 52 at the connection point between the communication passage 52 and the liquid chamber 131 may include the entire outer edge of the liquid chamber 131 (inlet passage 53). This allows the liquid discharge head 1 to eliminate or further reduce the area of ​​corners where the liquid flow velocity slows down at the connection point between the communication passage 52 and the liquid chamber 131. Therefore, the liquid discharge head 1 can reduce the possibility of bubbles remaining at the connection point and improve bubble discharge performance. Consequently, the liquid discharge head 1 can reduce, for example, the deterioration of the liquid discharge characteristics. Also, even if bubbles remain, the liquid can be easily discharged from the communication passage 52 and the liquid chamber 131 during purging.

[0097] Furthermore, as shown in Figure 10, at the connection point between the communication passage 52 and the liquid chamber 131, the difference (L2-L3) between the maximum width L2 of the communication passage 52 in the width direction of the liquid chamber 131 and the maximum width L3 of the liquid chamber 131 (inlet passage 53) may be smaller than the difference (L1-L2) between the maximum width L1 of the supply passage 51 and the maximum width L2 of the communication passage 52 in the width direction of the liquid chamber 131 at the connection point between the supply passage 51 and the communication passage 52.

[0098] As mentioned above, for example, the maximum width L1 of the supply passage 51 is 45 to 49 μm, the maximum width L2 of the connecting passage 52 is 35 to 45 μm, and the maximum width L3 of the inlet passage 53 of the liquid chamber 131 is 30 to 35 μm. When etching forms a deep aperture in the Z direction (hereinafter also referred to as a vertical aperture) consisting of the supply passage 51, the connecting passage 52, and the inlet passage 53 of the liquid chamber 131, tolerances occur when forming the supply passage 51, tolerances occur when forming the connecting passage 52, and positional misalignment occurs when forming the bonding film 31. Taking these processing accuracies into consideration, the maximum values ​​of each passage are designed so that even with variations in tolerances or positional misalignment, the lower passage does not protrude from the upper passage, and the passages narrow from top to bottom in the order of supply passage 51, connecting passage 52, and inlet passage 53.

[0099] In particular, among the vertical apertures, the supply passage 51 is formed by etching a support substrate 2 with a thickness of 200 to 400 μm. In contrast, the connecting passage 52 is formed by etching an actuator substrate 3 with a thickness of 30 to 75 μm. For this reason, the tolerance when forming the supply passage 51 is more prone to reduced accuracy than the tolerance when forming the connecting passage 52. In this embodiment, the difference between the maximum width L1 of the supply passage 51 and the maximum width L2 of the connecting passage 52 (L1-L2) may be larger than the difference between the maximum width L2 of the connecting passage 52 and the maximum width L3 of the inlet passage 53 of the liquid chamber 131 (L2-L3). This prevents the lower connecting passage 52 from protruding from the upper supply passage 51 even with tolerances when forming the supply passage 51, and ensures that the vertical aperture narrows from the supply passage 51 to the connecting passage 52. With this configuration, the vertical aperture is formed so that it narrows as it goes downwards from the supply passage 51 to the connecting passage 52 and then to the inlet passage 53. Therefore, the liquid discharge head 1 can reduce the possibility of air bubbles remaining at both the first and second stage connection points of the vertical aperture.

[0100] When the bonding direction between the support substrate 2 and the bonding layer 3a (bonding film 31), i.e., the Z-axis direction, is considered the first direction, the length of the supply passage 51 in the first direction may be longer than the length of the connecting passage 52 in the first direction. For example, the length of the supply passage 51 is the length from the top surface to the bottom surface of the support substrate 2, for example, 200 to 400 μm. The length of the connecting passage 52 is the length of the bonding layer 3a, i.e., the length from the top surface of the bonding film 31 to the bottom surface of the diaphragm 38, for example, several μm to 20 μm. Since the supply passage 51 is located upstream of the connecting passage 52, the liquid discharge head 1 can rectify the uneven velocity vectors of the liquid flowing in the flow path by making the length of the supply passage 51 in the first direction longer than the length of the connecting passage 52 in the first direction. As a result, the liquid flow becomes smoother, and the retention of air bubbles in the flow path can also be reduced.

[0101] Furthermore, the length of the liquid chamber substrate 3b in the first direction may be longer than the length of the bonding layer 3a. For example, the length of the liquid chamber substrate 3b in the first direction may be 30 μm or more, which is longer than the length of the bonding layer 3a, which is several μm to 20 μm. This allows the liquid discharge head 1 to improve the strength of the liquid chamber substrate 3b that receives the force of the piezoelectric element 36.

[0102] Furthermore, as shown in Figures 7 and 8A, the bonding film 31 may constitute part of the communication passage 52. On the side surface of the communication passage 52, the bonding film 31, protective layer 32, and diaphragm 38 are exposed in that order from top to bottom. Therefore, the bonding film 31 is connected to the communication passage 52. Rather than providing another layer on the side surface of the bonding film 31 so that the bonding film 31 is not connected to the communication passage 52, the manufacturing cost and time of the liquid discharge head 1 can be reduced by having the bonding film 31 constitute part of the communication passage 52 and not providing another layer.

[0103] Furthermore, the bonding film 31 is SiO ２ It may be made of insulating material. SiO ２ The insulating material is impermeable to liquids such as ink. This reduces the possibility of the liquid dispensing head 1 coming into contact with the piezoelectric element 36 and the liquid. As a result, the liquid dispensing head 1 can reduce the possibility of the piezoelectric element 36 short-circuiting.

[0104] Furthermore, the protective layer 32 may constitute part of the communication passage 52 at a position below the bonding film 31. SiN insulating material is impermeable to liquids such as ink. This reduces the possibility of the liquid ejection head 1 coming into contact with the piezoelectric element 36 and the liquid. As a result, the piezoelectric element 36 can reduce the possibility of short-circuiting. Furthermore, the adhesion layer 34 may constitute part of the communication passage 52. SiN insulating material is impermeable to liquids such as ink. This reduces the possibility of the liquid ejection head 1 coming into contact with the piezoelectric element 36 and the liquid.

[0105] If the actuator 30 is connected to a passage 52 through which liquid flows, the actuator 30 may be corroded by the liquid. In contrast, the actuator 30 in this embodiment is not connected to the passage 52. As a result, the actuator 30 can reduce the possibility of corrosion caused by the liquid passing through the passage 52.

[0106] As shown in Figures 7, 8A, and 10, an insulating film 33 and a bonding film 31 may be located between the actuator 30 including the common electrode 35 and the communication passage 52. Between the actuator 30 and the communication passage 52, SiO ２ The presence of the insulating film 33 and bonding film 31, which are insulating materials, further reduces the possibility of the actuator 30 being corroded by liquids. Furthermore, in addition to the insulating film 33 and bonding film 31, a protective layer 32 and / or an adhesion layer 34 may be located between the actuator 30 and the communication passage 52. The presence of the protective layer 32 and / or an adhesion layer 34, which are insulating materials of SiN, between the actuator 30 and the communication passage 52 further reduces the possibility of the actuator 30 being corroded by liquids.

[0107] The insulating film 33 and the common electrode 35 are penetrated by the communication passage 52, which is located inside the insulating film 33 and the common electrode 35. When the width direction (Y-axis direction) of the liquid chamber 131 in a plan view is taken as the second direction, as shown in Figures 8A and 10, the maximum width L4 (diameter) in the second direction of the opening 33h of the insulating film 33 located on the outer circumference side of the side of the communication passage 52 is, for example, 49 to 55 μm. Also, the maximum width L5 (diameter) in the second direction of the opening 35h of the common electrode 35 located on the outer circumference side of the opening 33h of the insulating film 33 is, for example, 55 to 65 μm.

[0108] Therefore, the distance in the second direction between the common electrode 35 of the actuator 30 and the side surface of the communication passage 52 ((L5 - L2) / 2) may be greater than the distance in the second direction between the side surface of the communication passage 52 and the side surface of the supply passage 51 ((L1 - L2) / 2). This allows the actuator 30 to further reduce the possibility of corrosion by the liquid. As a result, the liquid discharge head 1 can have improved electrical stability.

[0109] Furthermore, as shown in Figure 7, the actuator 30 has a portion where the bonding film 31 and insulating film 33 are not located. The portion of the actuator 30 where the bonding film 31 and insulating film 33 are not located is exposed to space 132. As a result, the liquid discharge head 1 can improve the displacement of the actuator 30 and enhance the liquid discharge performance from the nozzle 41. Note that the liquid discharge head 1 forms a portion of the actuator 30 where the bonding film 31 and insulating film 33 are not located by etching until the actuator 30 is exposed.

[0110] <Liquid Chamber Configuration> <First Embodiment> The configuration and size of the liquid chamber 131 will be described with reference to Figures 11 and 12. Figure 11 is a cross-sectional view of the support substrate 2, actuator substrate 3, and nozzle substrate 4 of the liquid discharge head 1 according to the first embodiment, and a plan view of the support substrate 2. Figure 12 is a diagram showing an example of the dimensions of each part shown in Figure 11. Figure 12(a) is a plan view of the actuator substrate 3 located below the support substrate 2.

[0111] As shown in Figures 11(a) and (b), the liquid chamber 131 may have a first portion 131a connected to the nozzle 41, a second portion 131b connected to the first portion 131a, and a third portion 131c connected to the second portion 131b and also connected to the communication passage 52. The first portion 131a is connected to the nozzle 41 on the nozzle substrate 4 near its end in the positive X-axis direction. The nozzle substrate 4 may have a substantially rectangular descender 42 located on the nozzle 41 and encompassing the entire nozzle 41 in a plan view. This makes the flow of liquid discharged from the nozzle 41 smoother, thereby improving bubble discharge. However, the first portion 131a may be connected to the nozzle 41 without going through the descender 42.

[0112] In the cross-sectional view of Figure 11(b), the actuator 30 that pressurizes the liquid chamber 131 is located above the first portion 131a. Also, the supply passage 51 and connecting passage 52 of the vertical aperture are located above the third portion 131c. The inlet passage 53 is the passage at the connection point between the third portion 131c and the connecting passage 52. Furthermore, in the plan view of Figure 11(a), the width of the second portion 131b in the second direction (Y-axis direction) may be smaller than the width of the first portion 131a in the second direction and the width of the third portion 131c in the second direction.

[0113] In the plan view of Figure 11(a), the first portion 131a has a portion where both sides are parallel along the X-axis direction, and a portion where one side is parallel to the X-axis direction and the other side is an inclined surface 131s1. The actuator 30 is located on the portion where both sides are parallel along the X-axis direction. The portion where the other side is an inclined surface 131s1 is connected to the second portion 131b.

[0114] In a plan view, the width of the second portion 131b in the second direction is smaller than the width of the first portion 131a in the second direction. When the actuator 30 is displaced, pressure is applied to the first portion 131a, and the pressure wave generated in the first portion 131a is transmitted to the nozzle 41, causing liquid to be discharged from the nozzle 41. At this time, because the width of the second portion 131b in the second direction is smaller than the width of the first portion 131a in the second direction, the pressure wave generated in the first portion 131a is less likely to be transmitted to the second portion 131b. As a result, the liquid discharge head 1 can reduce so-called crosstalk, in which a pressure wave generated in the liquid chamber 131 of one channel is transmitted to the liquid chamber 131 of another channel via the common flow path 123.

[0115] In particular, as shown in Figure 9, the communication passages 52 of each channel in channel groups 10a and 10b are located side by side in close proximity, making it easy for crosstalk to occur from one adjacent channel to the other in channel groups 10a and 10b. In contrast, the second portion 131b in this embodiment functions as a throttling mechanism, making it difficult for pressure waves generated in the first portion 131a to propagate to the second portion 131b. This reduces crosstalk from the close-proximity communication passages 52 to the other adjacent channel via the common flow path 123. When channel groups 10a and 10b are arranged side by side in a row, the throttling function of the second portion 131b in this embodiment is particularly important for improving the performance of the liquid discharge head 1.

[0116] Furthermore, in the plan view of Figure 11(a), the third portion 131c has a portion where both sides are parallel along the X-axis direction, and a portion where one side is parallel to the X-axis direction and the other side is an inclined surface 131s2. A connecting passage 52 is located on the portion where both sides are parallel along the X-axis direction. A supply passage 51 is located on the connecting passage 52. The portion where the other side is an inclined surface 131s2 is connected to the second portion 131b on the opposite side from the first portion 131a.

[0117] In the plan view of Figure 11(a), the width of the second portion 131b in the second direction is smaller than the width of the third portion 131c in the second direction. Therefore, the liquid discharge head 1 can improve the bubble discharge performance when liquid flows from the third portion 131c to the second portion 131b.

[0118] Furthermore, as shown in Figure 11(b), the heights (lengths in the Z-axis direction) of the second portion 131b and the third portion 131c may be the same. This allows the liquid discharge head 1 to improve the machining accuracy in the height direction during etching of the liquid chamber 131.

[0119] As shown in Figure 5, the manifold member 12 may have a damper chamber 125 in a part of the inner wall of the common flow path 123 via a damper film 124. The damper chamber 125 is designed to absorb pressure waves transmitted from each channel via the common flow path 123 and the damper film 124. As a result, when pressure waves that may cause crosstalk arrive from each channel, the damper film 124 and the damper chamber 125 absorb the pressure waves, thereby reducing the crosstalk generated via the common flow path 123.

[0120] Furthermore, in a plan view, one side of the first portion 131a, the second portion 131b, and the third portion 131c extends in a straight line in the X-axis direction. In other words, in the plan view of Figure 11(a), if the direction perpendicular to the width direction (second direction: Y-axis direction) of the liquid chamber 131 is defined as the third direction (X-axis direction), then one of the two sides of the first portion 131a, the second portion 131b, and the third portion 131c extending in the third direction is a straight line in a plan view, while the other side has inclined surfaces 131s1 and 131s2. The liquid chamber 131 can reduce the possibility of bubble retention if one side is a straight line in a plan view and has no inclined surface, and only the other side has an inclined surface, rather than having inclined surfaces on both sides of the first portion 131a, the second portion 131b, and the third portion 131c. As a result, the liquid discharge head 1 can improve the bubble discharge performance when flowing liquid from the liquid chamber 131 to the nozzle 41.

[0121] The supply passage 51, communication passage 52, liquid chamber 131, descender 42, nozzle 41, and space 132 may be formed by etching.

[0122] The dimensions of each part shown in Figure 12 are noted below. Note that, for convenience, the actuator 30 and space 132 are omitted from the illustration in Figure 12. Z-axis length of support substrate 2: 200-400 μm Z-axis length of actuator substrate 3: 30-75 μm Z-axis length of nozzle substrate 4: 75-150 μm Z-axis length of liquid chamber 131: 30-75 μm X-axis length of liquid chamber 131: 650-1000 μm X-axis length of first part 131a (straight portion): 400-600 μm X-axis length of first part 131a (inclined portion): 50-100 μm X-axis length of second part 131b: 150-200 μm X-axis length of third part 131c (inclined portion): 10-30 μm X-axis length of third part 131c (straight portion): 40-70 μm Y-axis width of first part 131a (maximum): 60-80 μm Y-axis width of second part 131b: Width of the third part 131c in the Y-axis direction (maximum): 10-30 μm Inclination angle θ2 of the first part 131a (inclined portion): Approximately 20-40° Inclination angle θ1 of the third part 131c (inclined portion): Approximately 40-60° Diameter φ1 of the supply passage 51: 45-49 μm Diameter φ2 of the communication passage 52: 35-45 μm Diameter φ3 of the nozzle 41: 15-25 μm

[0123] In one embodiment, the recording device (for example, a printer 100) may include the liquid ejection head 1 of one embodiment and a control unit (for example, a control unit 200) that controls the liquid ejection head 1.

[0124] <Effects of one embodiment> For example, a liquid discharge head 1 according to one embodiment includes a first substrate (for example, a support substrate 2) having a supply passage 51 for supplying liquid, and a bonding layer 3a bonded to the first substrate, the bonding layer 3a having a second substrate (for example, an actuator substrate 3) connected to the supply passage 51 and having a communication passage 52 for supplying liquid to a nozzle 41. At the connection between the supply passage 51 and the communication passage 52, the cross-sectional area of ​​the supply passage 51 is larger than the cross-sectional area of ​​the communication passage 52.

[0125] With this configuration, at the connection point between the supply passage 51 and the connecting passage 52, the cross-sectional area of ​​the supply passage 51 is larger than the cross-sectional area of ​​the connecting passage 52. Therefore, at the connection point, it is possible to eliminate or reduce the area at the corner where the flow velocity of the liquid flowing from the supply passage 51 to the connecting passage 52 slows down. As a result, the liquid discharge head 1 can reduce the possibility of air bubbles remaining at the connection point and improve air bubble discharge performance. This allows the liquid discharge head 1 to reduce, for example, deterioration of the liquid discharge characteristics. Furthermore, even if air bubbles remain, the liquid discharge head 1 can easily discharge the liquid from the supply passage 51 and the connecting passage 52 during purging.

[0126] Furthermore, the second substrate may include a liquid chamber substrate 3b connected to the communication passage 52 and having a liquid chamber 131 that connects the communication passage 52 and the nozzle 41. In a plan view, the maximum width of the communication passage 52 in the width direction of the liquid chamber 131 at the connection portion between the communication passage 52 and the liquid chamber 131 may be greater than the maximum width of the liquid chamber 131 in the same width direction. This allows the liquid discharge head 1 to eliminate or reduce the corner region at the connection portion between the communication passage 52 and the liquid chamber 131 where the flow velocity of the liquid flowing from the communication passage 52 to the liquid chamber 131 slows down. As a result, the bubble discharge performance can be improved throughout the entire vertical aperture.

[0127] Furthermore, the liquid chamber 131 may have a first portion 131a connected to the nozzle 41, a second portion 131b connected to the first portion 131a, and a third portion 131c connected to the second portion 131b and also connected to the communication passage 52. In a plan view, the width of the second portion 131b in the second direction (Y-axis direction) may be smaller than the width of the first portion 131a in the second direction and the width of the third portion 131c in the second direction.

[0128] In a plan view, the width of the second portion 131b in the second direction is smaller than the width of the first portion 131a in the second direction, thus reducing crosstalk. Also, in a plan view, the width of the second portion 131b in the second direction is smaller than the width of the third portion 131c in the second direction, so the liquid discharge head 1 can improve the bubble discharge performance when liquid flows from the third portion 131c to the second portion 131b.

[0129] <Second Embodiment> Referring to Figure 13, the liquid discharge head 1 according to the second embodiment will be described. In the second embodiment, components not mentioned may be the same as or different from those in the first embodiment described above.

[0130] Figure 13 shows a cross-sectional view of the support substrate 2, actuator substrate 3, and nozzle substrate 4 of the liquid discharge head 1 according to the second embodiment, and a plan view of the support substrate 2.

[0131] As shown in Figure 13(a), when the support substrate 2 is viewed from the Z-axis direction, the supply path 51 has a shape with a longitudinal direction and a transverse direction. When viewed from the Z-axis direction, the longitudinal direction of the supply path 51 is the longitudinal direction of the actuator 30, i.e., the X-axis direction. In other words, the longitudinal direction of the supply path 51 when viewed from the Z-axis direction is aligned with the longitudinal direction of the actuator 30. This makes it possible to reduce the spacing between multiple adjacent supply paths 51 in the transverse direction of the actuator 30, i.e., the Y-axis direction, compared to the case where the longitudinal direction of the supply path 51 when viewed from the Z-axis direction is not aligned with the longitudinal direction of the actuator 30. Note that, when viewed from the Z-axis direction, the longitudinal direction of the supply path 51 is the longitudinal direction of the actuator 30, but this is not the only case. The transverse direction of the supply path 51 is sufficient as long as it intersects with the longitudinal direction of the actuator 30.

[0132] As shown in Figure 13(a), when viewed from the Z-axis direction, the supply path 51 is oval-shaped. An oval shape is the trajectory of moving the center of a circle along a line segment. An oval shape is composed of a part of a circle and a straight line. As shown in Figure 13(b), the opening width in the X-axis direction of the supply path 51 opening into the support substrate 2 is larger than the opening width in the X-axis direction of the supply path 51 in the first embodiment shown in Figure 11(b). In the second embodiment, the supply path 51 is described as oval-shaped, but is not limited to this. When viewed from the Z-axis direction, the supply path 51 may be rectangular, elliptical, or other shapes, with the longitudinal direction of the supply path 51 being the longitudinal direction of the actuator 30.

[0133] Furthermore, the following additional information is disclosed with respect to the above embodiments. <Additional Information> (1) A liquid discharge head comprising: a first substrate having a supply passage for supplying liquid; and a second substrate including a bonding layer bonded to the first substrate, the bonding layer being connected to the supply passage and having a communication passage for supplying the liquid to a nozzle, wherein at the connection portion between the supply passage and the communication passage, the cross-sectional area of ​​the supply passage is greater than the cross-sectional area of ​​the communication passage. (2) The liquid discharge head according to (1), wherein in a plan view, the outer edge of the supply passage at the connection portion between the supply passage and the communication passage includes the entire outer edge of the communication passage. (3) The liquid discharge head according to (1) or (2), wherein the second substrate includes a liquid chamber substrate connected to the communication passage and having a liquid chamber that communicates the communication passage and the nozzle, wherein in a plan view, the maximum width of the communication passage in the width direction of the liquid chamber at the connection portion between the communication passage and the liquid chamber is greater than the maximum width of the liquid chamber in the width direction. (4) In a plan view, the outer edge of the communication passage at the connection between the communication passage and the liquid chamber includes the entire outer edge of the liquid chamber in a direction perpendicular to the width direction and in a direction where the nozzle is not located, from a virtual line passing through the center of the cross-section of the communication passage and along the width direction of the liquid chamber. The liquid discharge head according to (3). (5) At the connection between the communication passage and the liquid chamber, the difference between the maximum width of the communication passage and the maximum width of the liquid chamber in the width direction of the liquid chamber is smaller than the difference between the maximum width of the supply path and the maximum width of the communication passage in the width direction of the liquid chamber at the connection between the supply path and the communication passage. The liquid discharge head according to any one of (1) to (5). (6) When the bonding direction between the first substrate and the bonding layer is defined as the first direction, the length of the supply path in the first direction is longer than the length of the communication passage in the first direction. The liquid discharge head according to any one of (1) to (5). (7) When the bonding direction between the first substrate and the bonding layer is defined as the first direction, the length of the liquid chamber substrate in the first direction is longer than the length of the bonding layer in the first direction. The liquid discharge head according to any one of (3) to (5).(8) The liquid discharge head according to any one of (3) to (5), wherein the liquid chamber has a first portion connected to the nozzle, a second portion connected to the first portion, and a third portion connected to the second portion and also connected to the communication passage, an actuator for pressurizing the liquid chamber is located above the first portion, and when the width direction of the liquid chamber in a plan view is defined as the second direction, the width of the second portion in the second direction is smaller than the width of the first portion in the second direction and the width of the third portion in the second direction. (9) The liquid discharge head according to (8), wherein when the direction perpendicular to the width direction of the liquid chamber in a plan view is defined as the third direction, one of the sides of the first portion and the third portion extending in the third direction has an inclined surface. (10) The liquid discharge head according to any one of (3) to (5), wherein the bonding layer comprises a diaphragm located on the liquid chamber substrate, an actuator located on the diaphragm, an insulating film located on at least a part of the actuator, and a bonding film located on at least a part of the insulating film, and the first substrate is located on the bonding film. (11) The liquid discharge head according to (10), wherein the bonding film is connected to the communication passage. (12) The liquid discharge head according to (11), wherein the bonding film is made of an insulating material. (13) The liquid discharge head according to any one of (10) to (12), wherein the actuator is not connected to the communication passage. (14) The liquid discharge head according to any one of (10) to (13), wherein the bonding film and the insulating film are located between the actuator and the communication passage. (15) The liquid discharge head according to (13), wherein when the width direction of the liquid chamber in a plan view is taken as the second direction, the distance in the second direction between the actuator and the side surface of the communication passage is greater than the distance in the second direction between the side surface of the communication passage and the side surface of the supply passage. (16) The liquid discharge head according to any one of (10) to (15), wherein the part above the actuator is a portion where the bonding film and the insulating film are not located. (17) A recording device comprising: the liquid discharge head according to any one of (1) to (16); and a control unit for controlling the liquid discharge head.

[0134] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0135] 1 Liquid discharge head 2 Support substrate 3 Actuator substrate 3a Bonding layer 3b Liquid chamber substrate 4 Nozzle substrate 10 MEMS chip 10a, 10b Channel group 12 Manifold member 30 Actuator 31 Bonding film 32 Protective layer 33 Insulating film 34 Adhesion layer 35 Common electrode 36 Piezoelectric element 37 Individual electrode 38 Diaphragm 51 Supply path 52 Connecting passage 53 Inlet path 100 Printer 131 Liquid chamber 200 Control unit

Claims

1. A liquid discharge head comprising: a first substrate having a supply passage for supplying liquid; and a second substrate including a bonding layer bonded to the first substrate, the bonding layer being connected to the supply passage and having a connecting passage for supplying the liquid to a nozzle, wherein at the connection point between the supply passage and the connecting passage, the cross-sectional area of ​​the supply passage is larger than the cross-sectional area of ​​the connecting passage.

2. In a plan view, the liquid discharge head according to claim 1, wherein the outer edge of the supply path at the connection point between the supply path and the communication passage includes the entire outer edge of the communication passage.

3. The liquid discharge head according to claim 1 or 2, wherein the second substrate is connected to the communication passage and includes a liquid chamber substrate having a liquid chamber that connects the communication passage and the nozzle, and in a plan view, the maximum width of the communication passage in the width direction of the liquid chamber at the connection portion between the communication passage and the liquid chamber is greater than the maximum width of the liquid chamber in the width direction.

4. In a plan view, the outer edge of the communication passage at the connection between the communication passage and the liquid chamber includes the entire outer edge of the liquid chamber in a direction perpendicular to the width direction and in a direction where the nozzle is not located, from a virtual line passing through the center of the cross-section of the communication passage and along the width direction of the liquid chamber.

5. The liquid discharge head according to claim 3 or 4, wherein the difference between the maximum width of the communication passage and the maximum width of the liquid chamber in the width direction at the connection point between the communication passage and the liquid chamber is smaller than the difference between the maximum width of the supply passage and the maximum width of the communication passage in the width direction at the connection point between the supply passage and the communication passage.

6. The liquid discharge head according to any one of claims 1 to 5, wherein, when the bonding direction between the first substrate and the bonding layer is defined as the first direction, the length of the supply path in the first direction is longer than the length of the communication passage in the first direction.

7. The liquid discharge head according to any one of claims 3 to 5, wherein, when the bonding direction between the first substrate and the bonding layer is defined as the first direction, the length of the liquid chamber substrate in the first direction is longer than the length of the bonding layer in the first direction.

8. The liquid dispensing head according to any one of claims 3 to 5, wherein the liquid chamber has a first portion connected to the nozzle, a second portion connected to the first portion, and a third portion connected to the second portion and also connected to the communication passage, and an actuator for pressurizing the liquid chamber is located above the first portion, and when the width direction of the liquid chamber in a plan view is defined as the second direction, the width of the second portion in the second direction is smaller than the width of the first portion in the second direction and the width of the third portion in the second direction.

9. The liquid dispensing head according to claim 8, wherein, when the direction perpendicular to the width direction of the liquid chamber is defined as the third direction in a plan view, one of the sides of the first portion and the third portion extending in the third direction has an inclined surface.

10. The liquid discharge head according to any one of claims 3 to 5, wherein the bonding layer comprises a diaphragm located on the liquid chamber substrate, an actuator located on the diaphragm, an insulating film located on at least a portion of the actuator, and a bonding film located on at least a portion of the insulating film, and the first substrate is located on the bonding film.

11. The liquid discharge head according to claim 10, wherein the bonding membrane is connected to the communication passage.

12. The liquid dispensing head according to claim 11, wherein the bonding film is made of an insulating material.

13. The liquid discharge head according to any one of claims 10 to 12, wherein the actuator is not connected to the communication passage.

14. The liquid discharge head according to any one of claims 10 to 13, wherein the bonding film and the insulating film are located between the actuator and the communication passage.

15. The liquid discharge head according to claim 13, wherein, when the width direction of the liquid chamber in a plan view is defined as the second direction, the distance in the second direction between the actuator and the side surface of the communication passage is greater than the distance in the second direction between the side surface of the communication passage and the side surface of the supply passage.

16. The liquid dispensing head according to any one of claims 10 to 15, wherein the actuator has a portion where the bonding film and the insulating film are not located.

17. A recording device comprising: a liquid dispensing head according to any one of claims 1 to 16; and a control unit for controlling the liquid dispensing head.

Images