Liquid dispensing head, liquid dispensing unit, device for dispensing liquid, and method for manufacturing a liquid dispensing head

Abstract

To provide an actuator that can suppress lowering of vibration displacement of a piezoelectric element, and to provide a liquid discharge head, a liquid discharge unit, a device for discharging liquid, and a method for manufacturing an actuator.SOLUTION: An actuator includes: a vibration film 103 laminated on a substrate in which a liquid chamber is formed and constituting part of a wall surface of the liquid chamber; a piezoelectric element 5 laminated on a surface on an opposite side to a side constituting the wall surface of the liquid chamber of the vibration film 103; drawing wires 9a, 9b drawn from the piezoelectric element 5 to supply power to the piezoelectric element 5; and a moisture-proof film 11 for covering the drawing wires 9a, 9b. The piezoelectric element 5 is partially covered by the moisture-proof film 11.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to ,liquid a liquid ejection head, a liquid ejection unit, an apparatus for ejecting liquid, and Liquid dispensing head a method for manufacturing the same.

Background Art

[0002] Conventionally, an actuator is known that includes a vibration film laminated on a substrate in which a liquid chamber is formed and constituting a part of the wall surface of the liquid chamber, a piezoelectric element laminated on the surface of the vibration film opposite to the side constituting the wall surface of the liquid chamber, lead wiring drawn out from the piezoelectric element to supply power to the piezoelectric element, and a moisture-proof film covering the lead wiring.

[0003] Patent Document 1 describes a liquid ejection head provided with the above actuator. The material of the insulating film covering the lead wiring of the actuator is SiN (silicon nitride) having moisture resistance, and the entire surface of the driving element that is the piezoelectric element is covered with the above insulating film.

Summary of Invention

Problems to be Solved by the Invention

[0004] However, there has been a problem that the vibration displacement of the piezoelectric element decreases.

Means for Solving the Problems

[0005] In order to solve the above-described problems, the present invention provides a liquid ejection head that includes an actuator having a vibration film laminated on a substrate in which a liquid chamber is formed and constituting a part of the wall surface of the liquid chamber, a piezoelectric element laminated on the surface of the vibration film opposite to the side constituting the wall surface of the liquid chamber, lead wiring drawn out from the piezoelectric element to supply power to the piezoelectric element, and a moisture-proof film covering the lead wiring, and ejects liquid in the liquid chamber from a nozzle by the actuator, wherein before the nozzle is provided on the actuator, The piezoelectric element comprises a first electrode laminated on the side of the vibrating membrane opposite to the side constituting the wall of the liquid chamber, a piezoelectric portion laminated on the first electrode, and a second electrode laminated on the piezoelectric portion. The first electrode, the piezoelectric portion, and the second electrode are provided within the vibration region of the vibrating membrane that vibrates due to the piezoelectric element. The lead wire comprises a first lead wire drawn from the first electrode and a second lead wire drawn from the second electrode. The first and second lead wires are formed on an insulating film covering the piezoelectric element, and only the area around the first lead wire, the area around the second lead wire, the area around the connection point between the first electrode and the first lead wire of the piezoelectric element, and the area around the connection point between the second electrode and the second lead wire of the piezoelectric element are covered with a moisture-proof film. the liquid ejection head is characterized by that.

Effects of the Invention

[0006] According to the present invention, it is possible to suppress the decrease in vibration displacement of the piezoelectric element. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic cross-sectional view showing the nozzle vibration type liquid discharge head in this embodiment. [Figure 2] A schematic perspective view showing the liquid dispensing head. [Figure 3] Enlarged cross-sectional view of section X in Figure 1. [Figure 4] A diagram showing an example of the area where a moisture-proof film is formed. [Figure 5] A diagram showing another example of the region where a moisture-proof film is formed. [Figure 6] A diagram showing yet another example of the region where the moisture barrier film is formed. [Figure 7] A diagram illustrating the process of forming a drive circuit, wiring section, and vibrating membrane on a flow channel substrate. [Figure 8] A diagram illustrating the process of depositing a first electrode layer, a piezoelectric layer, and a second electrode layer on a vibrating film. [Figure 9] A diagram illustrating the process of forming an insulating film. [Figure 10] A diagram illustrating the process of forming multiple contacts. [Figure 11] A diagram illustrating the process of forming the lead wires. [Figure 12] A diagram illustrating the process of forming a moisture barrier. [Figure 13] A diagram illustrating the process of forming a moisture-proof film on each lead wire and a portion of the piezoelectric element. [Figure 14] A diagram illustrating the process of forming a film on the nozzle formation area. [Figure 15] A diagram illustrating the process of forming the nozzle and pad opening. [Figure 16] A diagram illustrating the process of forming a pressurized liquid chamber. [Figure 17]A diagram showing an example in which electrical connection pads are provided on a side surface of a liquid ejection head. [Figure 18] A diagram showing a modified example of the liquid ejection head. [Figure 19] A diagram showing an example in which electrical connection pads are provided on a side surface of the liquid ejection head of the modified example. [Figure 20] A schematic explanatory diagram of a printing apparatus which is an inkjet recording apparatus as a liquid ejecting apparatus in the present embodiment. [Figure 21] A plan explanatory diagram illustrating an example of a head unit of the printing apparatus according to the present embodiment. [Figure 22] A plan explanatory diagram of a main part of the printing apparatus of the present example. [Figure 23] A side explanatory diagram of a main part of the printing apparatus of the present example. [Figure 24] A plan explanatory diagram of a main part of the liquid ejection unit of the present example. [Figure 25] A front explanatory diagram of the liquid ejection unit of the present example. [Mode for Carrying Out the Invention]

[0008] Hereinafter, an embodiment in which the present invention is applied to a liquid ejection head provided in a liquid ejecting apparatus will be described. The present invention is not limited to the embodiments described below, and modifications such as other embodiments, additions, corrections, and deletions can be made within the scope conceivable by those skilled in the art, and any aspect that achieves the functions and effects of the present invention shall be included within the scope of the present invention.

[0009] The liquid ejection head according to the present embodiment is a nozzle vibration type liquid ejection head that ejects liquid in a pressurized liquid chamber from nozzles by varying the pressure in the pressurized liquid chamber with an actuator portion having the nozzles. The nozzle vibration method is characterized in that liquid droplets can be ejected with a smaller force compared to a general unimorph type piezo head (which ejects liquid by vibrating the surface opposite to the surface of the pressurized liquid chamber having the nozzles), and power saving of the actuator can be achieved.

[0010] Increasing nozzle density limits the space available for laying out wiring for voltage application, making it difficult to construct wiring on the substrate surface. By constructing wiring and drive circuits within the substrate, wiring can be laid out even in configurations with high nozzle density. Generally, lead zirconate titanate (PZT) is widely used as a material for piezoelectric elements due to its high piezoelectric properties, but the deposition and crystallization temperature of PZT is 600°C or higher. If PZT is used as the material for the piezoelectric element, the drive circuit and its wiring within the substrate cannot withstand high temperatures, so a piezoelectric material with a lower deposition temperature than PZT is required. In that case, it becomes necessary to select a material with lower piezoelectric properties than PZT. However, as mentioned above, the nozzle vibration method has the characteristic of being able to eject droplets with less force than a general unimorph type piezo head (which ejects liquid by vibrating a surface facing a surface that has a communication port communicating with the nozzle of the pressurized liquid chamber), so droplets can be ejected well even if a material with lower piezoelectric properties than PZT is selected. Therefore, even piezoelectric materials with low film formation and crystallization temperatures, such as lead-free materials, but with low power, can effectively eject droplets. This allows for the construction of wiring and drive circuits within the substrate, enabling higher density applications. Furthermore, the nozzle vibration method allows for a smaller pressurized liquid chamber volume, which in turn enables a smaller head size.

[0011] Figure 1 is a schematic cross-sectional view showing the nozzle vibration type liquid discharge head in this embodiment, and Figure 2 is a schematic perspective view showing the liquid discharge head. The liquid discharge head 1 includes an actuator 110, a flow path substrate 100, and a frame member 120.

[0012] The actuator 110 is thin-film in shape and includes a vibrating membrane 103, a plurality of nozzles 2 for discharging liquid, and an annular piezoelectric element 5 arranged around the nozzles 2. The flow channel substrate 100 has a plurality of pressurized liquid chambers (also called individual liquid chambers) 4, each communicating with a plurality of nozzles 2. The frame member 120 has a common liquid chamber 3 that leads to the plurality of pressurized liquid chambers 4.

[0013] Electrical connection pads 6 are provided at both ends of the liquid dispensing head 1 for connecting to external electrical components such as a power supply.

[0014] Figure 3 is an enlarged cross-sectional view of portion X in Figure 1. The flow channel substrate 100 is an SOI (Silicon on Insulator) substrate and has a drive circuit 101 and a wiring section 102 on the side where the vibrating film 103 is deposited. The drive circuit 101 is a circuit including transistors and resistors. The wiring section 102 has a wiring section for applying a bias to the first electrode 51 and a wiring section for applying a bias to the second electrode 53. The wiring section 102 is also electrically connected to the electrical connection pad 6 via a third contact 7c opened in the vibrating film 103.

[0015] The actuator 110 has a nozzle-forming portion (film) 111 that covers the piezoelectric element 5 and has multiple nozzles 2 formed thereon. A water-repellent film may be provided on the nozzle surface of this nozzle-forming portion 111. By forming a liquid-repellent film on the nozzle surface, the adhesion of liquid to the nozzle surface can be suppressed, and the liquid discharged from the nozzle 2 can be prevented from being affected by the liquid adhering to the nozzle surface. If the solvent of the liquid is aqueous, perfluorodecyltrichlorosilane or perfluorooctyltrichlorosilane can be used as the material for the liquid-repellent film.

[0016] The piezoelectric element 5 of the actuator 110 has a first electrode 51 (also called the lower electrode), a piezoelectric film 52, and a second electrode 53 (also called the upper electrode). The piezoelectric element 5 is covered with an insulating film 8.

[0017] The insulating film 8 has a perforated fourth contact 7d for electrically connecting to the first electrode 51 and a perforated fifth contact 7e for electrically connecting to the second electrode 53. The insulating film 8 also has a first lead wire 9a for electrically connecting the first electrode of the piezoelectric element to the wiring portion 102 of the flow channel substrate 100, and a second lead wire 9b for electrically connecting the second electrode 53 of the piezoelectric element to the wiring portion 102 of the flow channel substrate 100.

[0018] The first lead wire 9a is electrodeally connected to the first electrode 51 via the fourth contact 7d, and is electrodeally connected to the wiring section 102 via the first contact 7a. The second lead wire 9b is electrodeally connected to the second electrode 53 via the fifth contact 7e, and is electrodeally connected to the wiring section 102 via the second contact 7b.

[0019] The first lead wire 9a and the second lead wire 9b are covered with a moisture-proof film 11. This prevents moisture that has entered the nozzle forming section 111, which is made of resin, from entering the first lead wire 9a and the second lead wire 9b, thereby suppressing corrosion of each lead wire.

[0020] Furthermore, it is preferable that the moisture-proof film 11 has electrical insulating properties. By having both insulating and moisture-proof functions as the moisture-proof film 11, the actuator 110 can be made thinner compared to when an insulating film is formed beneath the moisture-proof film 11. This makes the vibrating membrane 103 more easily deformable, and the vibration efficiency can be improved.

[0021] As the moisture-proof film 11, it is preferable to use SiN (silicon nitride), which is widely used as a moisture-proof film for semiconductors, as this allows the moisture-proof film 11 to have two functions: insulation and moisture resistance. In addition, as the material of the moisture-proof film 11, oxides of Al (aluminum), Ta (tantalum), Nb (niobium), Ti (titanium), Hf (hafnium), Zr (zirconium), and W (tungsten), which readily form dense films with ALD, can also be used.

[0022] Figure 4 shows an example of the formation region of the moisture-proof film 11. As shown in Figure 4, the moisture-proof film 11 covers the first lead wire 9a, the second lead wire 9b, the fourth contact 7d, the fifth contact 7e, and their surroundings. Therefore, the piezoelectric element 5 is covered by the moisture-proof film 11 only around the portion of the first lead wire 9a that overlaps with the piezoelectric element 5, the portion of the second lead wire 9b that overlaps with the piezoelectric element, the fourth contact 7d, and the fifth contact 7e. In other words, the electrical circuit portion is covered by the moisture-proof film 11.

[0023] Since the moisture-proof film 11 is basically a dense and rigid film, if the entire piezoelectric element is covered with the moisture-proof film 11, the rigidity of the piezoelectric element 5 increases, resulting in a decrease in vibration displacement. In particular, in this embodiment, as described above, a piezoelectric material with a low film formation and crystallization temperature but low power, such as a lead-free material, is used, so the effect of the decrease in vibration displacement due to the moisture-proof film 11 is significant.

[0024] Therefore, in this embodiment, as shown in Figure 4, only a portion of the piezoelectric element 5 is covered with the moisture-proof film 11. Specifically, only the areas around the first lead wire 9a, the second lead wire 9b, the fourth contact 7d, and the fifth contact 7e of the piezoelectric element 5 are covered with the moisture-proof film 11. As a result, compared to the case where the entire piezoelectric element is covered with the moisture-proof film 11, the decrease in vibration displacement of the piezoelectric element 5 can be suppressed, and the vibrating membrane 103 can be vibrated effectively.

[0025] As will be described later, the first and second electrodes of the piezoelectric element 5 are made of highly corrosion-resistant metals such as iridium (Ir) and molybdenum (Mo). Therefore, the first and second electrodes of the piezoelectric element are virtually immune to corrosion caused by moisture entering the nozzle forming section 111.

[0026] Figure 5 shows another example of the formation region of the moisture-proof film 11. In the example shown in Figure 5, the portion of the first electrode 51 of the piezoelectric element where the piezoelectric film 52 is not laminated, the portion of the piezoelectric film 52 where the second electrode 53 is not laminated, and the area around and edges of the fifth contact 7e of the second electrode 53 are covered with the moisture-proof film 11. In other words, the region between the fourth contact 7d and the fifth contact 7e within the area of ​​the piezoelectric element centered on the nozzle is covered in an annular shape with the moisture-proof film 11. The portions of the first electrode 51 of the piezoelectric element 5 where the piezoelectric film 52 is not laminated, and the portions of the second electrode 53 of the piezoelectric film 52 where the piezoelectric film 52 is not laminated, are portions that hardly displace during operation. Therefore, as shown in Figure 5, even if the portions of the first electrode 51 and second electrode 53 of the piezoelectric element 5 where the piezoelectric film 52 is not laminated are covered by the moisture-proof film 11, and the rigidity of these portions increases, there is almost no decrease in the vibration displacement of the piezoelectric element 5. Thus, as shown in Figure 5, even if only a portion of the second electrode 53 is covered by the moisture-proof film 11, the decrease in the vibration displacement of the piezoelectric element 5 can be suppressed, and the vibrating film 103 can be vibrated effectively.

[0027] In Figure 5, the moisture-proof film 11 covers the area from the fourth contact 7d to the edge of the second electrode 53 in an annular shape, and the portion covering the fifth contact 7e, which is located on the nozzle side (inward) of the edge of the second electrode 53, protrudes towards the nozzle. Therefore, there is a risk that the load on the piezoelectric element will not be evenly distributed due to vibration. For this reason, the moisture-proof film 11 may be made to cover the area between the fourth contact 7d and the fifth contact 7e of the piezoelectric element 5 in an annular shape, and the moisture-proof film 11 covering the piezoelectric element may not have a shape that protrudes towards the nozzle. This would ensure that the piezoelectric element 5 is evenly covered by the moisture-proof film 11 around the nozzle 2, and the load on the moisture-proof film 11 due to vibration can be evenly distributed.

[0028] Figure 6 shows yet another example of the formation region of the moisture-proof film 11. In the example shown in Figure 6, the area of ​​the vibrating membrane 103 other than the vibration region 103a is covered with the moisture-proof film 11. The vibration region 103a of the vibrating membrane 103 is the part that constitutes the bottom surface of the pressurized liquid chamber 4 of the vibrating membrane 103. The vibration region 103a is covered with the moisture-proof film 11 only around the first and second lead wires 9a and 9b that cross this vibration region. In this way, by covering only a part of the vibration region 103a of the vibrating membrane 103 (around the first and second lead wires 9a and 9b) with the moisture-proof film 11, the Young's modulus of the vibration region 103a can be lowered compared to a configuration in which the entire vibration region 103a is covered with the moisture-proof film 11. As a result, the vibration region 103a can be easily vibrated by the displacement of the piezoelectric element 5, and the vibration efficiency can be increased compared to a configuration in which the entire vibration region 103a is covered with the moisture-proof film 11.

[0029] In addition, in the configuration shown in Figure 6, in order to equalize the load on vibrations caused by the moisture-proof film 11, the region between the fourth contact 7d and the fifth contact 7e of the piezoelectric element 5 may be covered in an annular shape with the moisture-proof film 11.

[0030] Alternatively, the first electrode 51 and the second electrode 53 may each be provided with lead-out wiring sections and directly connected to the wiring section 102 via contacts opened in the diaphragm. Furthermore, an adhesion-improving film may be formed on the moisture-proof film 11 to ensure adhesion with the nozzle forming portion 111.

[0031] Furthermore, if the inner surfaces of the pressurized liquid chamber 4 and nozzle 2 are eroded by the liquid, a liquid-resistant protective film may be provided on the inner surfaces of the pressurized liquid chamber 4 and nozzle 2. Examples of protective films include metal oxides that form a passive body. Examples of metals for the metal oxide include tantalum (Ta), niobium (Nb), titanium (Ti), zirconium (Zr), hafnium (Hr), and tungsten (W), which have high compatibility with oxidation states. Zr and Hr, which have valencies similar to SiO2, or Ta, which have valencies around them, are particularly desirable.

[0032] Furthermore, it is preferable that the protective film is hydrophilic. The hydrophilic nature of the protective film allows the liquid to spread more easily to the inner surface of the pressurized liquid chamber 4 and nozzle 2 during filling. As a result, the liquid filling efficiency can be improved. If the solvent for the liquid is aqueous, a mixture of metal oxide and silicon dioxide (SiO2) at the molecular level can be used. Hydrophilicity can be imparted to the protective film by substituting the oxygen atoms in the SiO2 on the surface of the protective film to create hydrophilic OH groups.

[0033] The liquid filling the liquid discharge head enters the nozzle 2 and forms a meniscus within the nozzle. By applying a predetermined drive waveform (voltage) to each electrode of the piezoelectric element 5, the piezoelectric film 52 vibrates, causing the vibrating film 103 to vibrate vertically in Figure 3. The vibration of the vibrating film 103 causes a pressure change in the liquid inside the pressurized liquid chamber, and the liquid is discharged from the nozzle 2.

[0034] Next, the manufacturing method of the liquid dispensing head of this embodiment will be described. Figures 7 to 16 are cross-sectional views showing a cross-section perpendicular to the direction of arrangement of the nozzles 2, illustrating the manufacturing process of the liquid discharge head of this embodiment.

[0035] First, as shown in Figure 7, a drive circuit 101 containing transistors, resistors, etc., and a wiring section 102 are formed on the silicon film of the flow channel substrate 100, which is an SOI (Silicon on Insulator) substrate. If the drive circuit 101 is not to be built into the flow channel substrate 100, an SI substrate may be used as the flow channel substrate 100.

[0036] Next, a vibrating film 103 is formed on the surface of the flow channel substrate 100 on which the drive circuit 101 and wiring section 102 are formed. The material of the vibrating film 103 can be any material that has at least insulating properties, such as SiO2, SiN, metal oxides, or resins. However, in order to increase the displacement, a material with a low Young's modulus is desirable, and considering the difference in the coefficient of linear expansion between the flow channel substrate 100 and the vibrating film 103, SiO2 (silicon dioxide), which has a relatively small difference, is the most desirable material for the vibrating film 103.

[0037] Next, as shown in Figure 8, a first electrode layer 151, a piezoelectric layer 152, and a second electrode layer 153 are deposited on the vibrating film 103. The first electrode layer 151 and the second electrode layer 153 are preferably made of metals with low electrical resistance and low reactivity, such as Ir and Mo.

[0038] As for the piezoelectric material constituting the piezoelectric layer 152, in this embodiment, when the drive circuit 101 and wiring section 102 are embedded in the flow channel substrate 100 to improve density, it is desirable to use a piezoelectric material whose film deposition temperature is 450°C or lower in order not to damage them. AlN is an example of a piezoelectric material whose film deposition temperature is 450°C or lower.

[0039] Furthermore, using AlN as the piezoelectric material offers the following advantages. Specifically, the piezoelectric properties can be improved by aligning the crystal orientation of the piezoelectric film 52, but to control this orientation, an orientation control layer is required between the vibrating film 103 and the first electrode 51. When the piezoelectric material of the piezoelectric film 52 is AlN, using AlN as the orientation control layer allows the lattice constant of the first electrode 51, which is made of Mo, to approach that of AlN. As a result, the crystal orientation of the piezoelectric film 52 is aligned, and the piezoelectric properties can be improved.

[0040] The first electrode layer 151 and the second electrode layer 153 are generally deposited using the sputtering method. For the deposition of the piezoelectric layer 152, sputtering and sol-gel methods can be used, but the latter requires a high deposition temperature and is therefore unsuitable for deposition on the flow channel substrate 100 having the drive circuit 101 and wiring section 102. For this reason, it is desirable to deposit the piezoelectric layer 152 using the sputtering method as well.

[0041] After forming the first electrode layer 151, the piezoelectric layer 152, and the second electrode layer 153, they are molded into a suitable shape as shown in Figure 9 to obtain a piezoelectric element 5 consisting of a first electrode 51, a piezoelectric film 52, and a second electrode 53. The first electrode layer 151, the piezoelectric layer 152, and the second electrode layer 153 can be easily processed by photolithography and etching to obtain the first electrode 51, the piezoelectric film 52, and the second electrode 53 in the desired shape. There are wet etching and dry etching methods, but dry etching is preferred because it can suppress corrosion of the electrodes 51, 53 and the piezoelectric film 52. Since residue tends to remain after dry etching, a cleaning step may be added after molding to remove the residue.

[0042] After forming the first electrode 51, the piezoelectric film 52, and the second electrode 53, an insulating film 8 is formed by deposition and etching as shown in Figure 9. The insulating film 8 is preferably made of the same SiO2 as the vibrating film 103, as it has insulating properties similar to the vibrating film 103, a low Young's modulus, and a coefficient of thermal expansion close to that of the constituent material.

[0043] After forming the insulating film 8, as shown in Figure 10, first to fifth contacts 7a to 7e with a hole shape are formed in the vibrating film 103 and the insulating film 8 by photolithography and etching. In addition, first to third contacts 7a to 7c are formed in the vibrating film 103, and a nozzle forming hole 103b for forming the nozzle 2 is also formed. It is preferable to process the nozzle forming hole 103b at the same time as the first to third contacts 7a to 7c, as this facilitates subsequent processing.

[0044] Next, as shown in Figure 11, the first lead wire 9a, the second lead wire 9b, and the electrical connection pad 6 are formed. The materials for each lead wire 9a, 9b and the electrical connection pad 6 are typically Al or AlCu alloy. In this process, the first lead wire 9a is electrically connected to the first electrode 51 via the fourth contact 7d and to the wiring section 102 via the first contact 7a. The second lead wire 9b is electrically connected to the second electrode 53 via the fifth contact 7e and to the wiring section 102 via the second contact 7b. Furthermore, the electrical connection pad 6 is electrically connected via the third contact 7c.

[0045] Next, as shown in Figure 12, after forming the moisture-proof film 11, it is processed by photolithography and etching to form the moisture-proof film 11 that covers the first lead wiring 9a, the second lead wiring 9b, the fourth contact 7d, and the fifth contact 7e, as shown in Figure 13. Through the above process, it becomes possible to drive the piezoelectric element 5.

[0046] Next, as shown in Figure 14, a nozzle forming portion 111 is formed. The nozzle forming portion 111 is formed by spin coating. As the material for the nozzle forming portion 111, it is desirable to use a resin that can be coated by spin coating, and from the viewpoint of chemical resistance, SU8 or BCB is desirable. Next, as shown in Figure 15, the nozzle 2 and pad opening 10 are formed by etching. The etching of the nozzle 2 and pad opening 10 is dry etching.

[0047] Next, as shown in Figure 16, the flow channel substrate 100 is processed by Si etching to form multiple circular pressurized liquid chambers 4. The pressurized liquid chambers 4 need to have a high aspect ratio of cross-section (the depth of the liquid chamber is greater relative to the diameter of the liquid chamber) in order to improve discharge efficiency and reduce crosstalk. Therefore, in this embodiment, the pressurized liquid chambers 4 are formed by DRIE (Deep Reactive Ion Etching). In this DRIE, CF-based gases such as CF4 and C4F8, and SF-based gases such as SF6 are used as etching gases.

[0048] Subsequently, the liquid discharge head 1 is formed by joining a frame member 120, which has a common liquid chamber 3 formed on its back surface, to the flow path substrate 100.

[0049] In a nozzle vibration type liquid discharge head, the positional accuracy of the actuator 110 having the nozzle and the flow channel substrate 100 greatly affects the discharge characteristics, requiring high dimensional accuracy during manufacturing. Therefore, when forming a liquid discharge head by joining the actuator 110 having the nozzle to the flow channel substrate 100 having a pressurized liquid chamber 4, a high-precision joining process is required. In contrast, in this embodiment, the actuator 110 is directly formed on the flow channel substrate 100 by sequentially depositing the materials constituting the actuator 110 onto the flow channel substrate 100 and then performing predetermined processing. This eliminates the need for a high-precision joining process, making it possible to easily form a liquid discharge head.

[0050] As shown in Figure 17, the wiring section 102 of the flow path substrate 100 may be extended to the end of the side surface of the liquid discharge head 1, and an electrical connection pad 6 for connecting to an external power supply or other electrical component may be electrically connected to the end of this wiring section 102. Alternatively, as shown in Figures 18 and 19, the flow path substrate 100 may be configured without the wiring section 102 or the drive circuit 101. Figure 18 shows an example in which one end of the first lead wire 9a and the second lead wire 9b is exposed to the outside and an electrical connection pad 6 is formed. Figure 19 shows an example in which the lead wire is extended to the end of the side surface of the liquid discharge head 1, and an electrical connection pad 6 is electrically connected to the end of this lead wire.

[0051] Next, an example of a liquid dispensing apparatus according to the present invention will be described with reference to Figures 20 and 21. Figure 20 is a schematic diagram illustrating a printing apparatus, which is an inkjet recording apparatus used as a liquid ejection device in this embodiment. Figure 21 is a plan view illustrating an example of a head unit of the printing apparatus according to this embodiment.

[0052] The printing apparatus 500, which is a device that discharges this liquid, includes a loading means 501 for loading the continuous body 510, and a guiding and transporting means 503 for guiding and transporting the continuous body 510 loaded from the loading means 501 to the printing means 505. The printing apparatus 500 also includes a printing means 505 for printing an image by discharging liquid onto the continuous body 510, a drying means 507 for drying the continuous body 510, and an unloading means 509 for unloading the continuous body 510.

[0053] The continuous body 510 is fed out from the main winding roller 511 of the loading means 501, guided and transported by the rollers of the loading means 501, the guiding and transporting means 503, the drying means 507, and the unloading means 509, and then wound up by the winding roller 591 of the unloading means 509. In the printing means 505, this continuous body 510 is transported on the transport guide member 559 facing the head unit 550, and an image is printed by the liquid discharged from the head unit 550.

[0054] In the printing apparatus 500 of this embodiment, the head unit 550 is equipped with the two head modules 100A and 100B described above in this embodiment on a common base member 552.

[0055] Then, when the direction in which the liquid discharge heads 1 are arranged in a direction perpendicular to the transport direction of head modules 100A and 100B is defined as the head array direction, the head rows 1A1 and 1A2 of head module 100A discharge liquid of the same color. Similarly, the head rows 1B1 and 1B2 of head module 100A are paired, the head rows 1C1 and 1C2 of head module 100B are paired, and the head rows 1D1 and 1D2 are paired, and the required color liquid is discharged from each.

[0056] Next, other examples of printing apparatus as a liquid dispensing device according to the present invention will be described with reference to Figures 22 and 23. Figure 22 is a plan view illustrating the main components of the printing apparatus in this example. Figure 23 is a side view illustrating the main components of the printing apparatus in this example.

[0057] The printing apparatus 500 in this example is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction by the main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is stretched across the left and right side plates 491A and 491B and holds the carriage 403 in a movable position. The carriage 403 is then reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 stretched between the drive pulley 406 and the driven pulley 407.

[0058] The carriage 403 is equipped with a liquid discharge unit 440 that integrates a liquid discharge head 1 and a head tank 441 according to the present invention. The liquid discharge head 1 discharges liquids of various colors, such as yellow (Y), cyan (C), magenta (M), and black (K). The liquid discharge head 1 is also mounted with a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and with the discharge direction facing downward. The liquid discharge head 1 is connected to a liquid circulation device, and the required color of liquid is circulated and supplied.

[0059] The printing apparatus 500 is equipped with a transport mechanism 495 for transporting paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412. The transport belt 412 picks up the paper 410 and transports it to a position facing the liquid discharge head 1. This transport belt 412 is an endless belt and is stretched between a transport roller 413 and a tension roller 414. Pickup can be performed by electrostatic attraction or air suction. The transport belt 412 moves in a circular motion in the sub-scanning direction as the transport roller 413 is rotationally driven by the sub-scanning motor 416 via a timing belt 417 and a timing pulley 418.

[0060] Furthermore, a maintenance and recovery mechanism 420 for maintaining and restoring the liquid discharge head 1 is positioned on one side of the carriage 403 in the main scanning direction, next to the transport belt 412. The maintenance and recovery mechanism 420 consists of, for example, a cap member 421 that caps the nozzle surface of the liquid discharge head 1, and a wiper member 422 that wipes the nozzle surface. The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the transport mechanism 495 are mounted on a housing that includes side plates 491A, 491B, and a back plate 491C.

[0061] In the printing apparatus 500 configured in this way, the paper 410 is fed onto the transport belt 412 and held in place, and the paper 410 is transported in the sub-scanning direction by the circular movement of the transport belt 412. Then, by moving the carriage 403 in the main scanning direction and driving the liquid ejection head 1 in accordance with the image signal, liquid is ejected onto the stationary paper 410 to form an image.

[0062] Next, another example of the liquid dispensing unit according to the present invention will be described with reference to Figure 24. Figure 24 is a plan view illustrating the main components of the liquid dispensing unit in this example.

[0063] The liquid discharge unit 440 consists of a housing portion comprising side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid discharge head 1, which are components of the device that discharges the liquid.

[0064] Furthermore, a liquid dispensing unit can also be configured by attaching the aforementioned maintenance and recovery mechanism 420 to, for example, the side plate 491B of the liquid dispensing unit 440.

[0065] Next, yet another example of the liquid dispensing unit according to the present invention will be described with reference to Figure 25. Figure 25 is a front view of the liquid dispensing unit in this example.

[0066] This liquid discharge unit 440 consists of a liquid discharge head 1 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

[0067] The flow path component 444 is located inside the cover 442. A head tank 441 can be included instead of the flow path component 444. Furthermore, a connector 443 for electrical connection to the liquid discharge head 1 is provided on the upper part of the flow path component 444.

[0068] In this application, the discharged liquid is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the head, but it is preferable that its viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or when heated or cooled. More specifically, it is a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a functional material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment. These can be used, for example, in inkjet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements or electronic circuit resist patterns, and material liquids for 3D molding.

[0069] The energy source for discharging liquid includes piezoelectric actuators (multilayer piezoelectric elements and thin-film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a diaphragm and a counter electrode.

[0070] A "liquid discharge unit" is a liquid discharge head with integrated functional components and mechanisms, and includes an assembly of parts related to liquid discharge. For example, a "liquid discharge unit" may include a combination of a liquid discharge head with at least one of the following components: a head tank, carriage, supply mechanism, maintenance and recovery mechanism, main scanning movement mechanism, and liquid circulation device.

[0071] Here, integration includes, for example, cases where the liquid dispensing head and functional components or mechanisms are fixed to each other by fastening, bonding, engaging, etc., or where one is held movably relative to the other. Furthermore, the liquid dispensing head and functional components or mechanisms may be configured to be detachable from each other.

[0072] For example, some liquid dispensing units have a liquid dispensing head and head tank integrated into one unit. Others have a liquid dispensing head and head tank integrated into one unit, connected to each other by tubes or similar means. In these liquid dispensing units, a unit including a filter can also be added between the head tank and the liquid dispensing head.

[0073] Additionally, some liquid dispensing units have an integrated liquid dispensing head and carriage.

[0074] Furthermore, some liquid dispensing units integrate the liquid dispensing head and the scanning mechanism by movably holding the liquid dispensing head in a guide member that constitutes part of the scanning mechanism. Others integrate the liquid dispensing head, carriage, and main scanning mechanism.

[0075] Furthermore, some liquid dispensing units integrate the liquid dispensing head, carriage, and maintenance / recovery mechanism by fixing a cap component, which is part of the maintenance / recovery mechanism, to a carriage to which the liquid dispensing head is attached.

[0076] Furthermore, some liquid discharge units have a head tank or a liquid discharge head to which flow path components are attached, to which a tube is connected, integrating the liquid discharge head and the supply mechanism. Through this tube, the liquid from the liquid storage source is supplied to the liquid discharge head.

[0077] The main scanning movement mechanism shall include the guide member alone. The supply mechanism shall also include the tube alone and the loading section alone.

[0078] Here, the "liquid dispensing unit" is described in combination with a liquid dispensing head, but the "liquid dispensing unit" also includes a head module or head unit that includes the liquid dispensing head mentioned above, as well as the functional components and mechanisms described above, all integrated together.

[0079] "Liquid dispensing devices" include devices that have a liquid dispensing head, liquid dispensing unit, head module, head unit, etc., and drive the liquid dispensing head to dispense liquid. Liquid dispensing devices include not only devices that can dispense liquid onto surfaces to which liquid can adhere, but also devices that dispense liquid into air or into liquid.

[0080] This "liquid dispensing device" may also include means for feeding, transporting, and dispensing paper onto materials to which liquid can adhere, as well as pre-treatment devices, post-treatment devices, etc.

[0081] For example, "devices that dispense liquids" include image forming machines, which dispense ink to form images on paper, and three-dimensional molding machines, which dispense molding liquid into a powder layer formed in layers to create three-dimensional objects.

[0082] Furthermore, "devices that dispense liquid" are not limited to those that visualize meaningful images such as letters or figures through the dispensed liquid. For example, devices that form patterns that do not have meaning in themselves, or devices that create three-dimensional images, are also included.

[0083] The term "materials to which liquid can adhere" above refers to materials to which liquid can adhere, at least temporarily, including materials that adhere and solidify, or materials that adhere and penetrate. Specific examples include recording media such as paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and inspection cells. Unless otherwise specified, it includes all materials to which liquid can adhere.

[0084] The materials referred to as "materials to which liquid can adhere" above include paper, thread, fibers, fabrics, leather, metal, plastic, glass, wood, ceramics, etc., as long as liquid can adhere to them, even temporarily.

[0085] Furthermore, "liquid dispensing devices" include devices in which the liquid dispensing head and the surface to which the liquid can adhere move relative to each other, but are not limited to these. Specific examples include serial-type devices in which the liquid dispensing head moves, and line-type devices in which the liquid dispensing head does not move.

[0086] Furthermore, other types of "liquid dispensing devices" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the paper's surface. There are also spray granulation devices that granulate fine particles of raw materials by spraying a compositional liquid, in which raw materials are dispersed in a solution, through a nozzle.

[0087] In this application, the terms image formation, recording, printing, copying, printing, and shaping are all considered synonymous.

[0088] Furthermore, although the above description focused on an example of applying the actuator of the present invention to a liquid discharge head, the actuator of the present invention can also be applied to micropumps, for example, as described in Japanese Patent Application Publication No. 2012-253087 and Japanese Patent Application Publication No. 2014-030008.

[0089] The above is just one example; each of the following embodiments produces its own unique effects. (Aspect 1) In an actuator 110 having a vibrating membrane 103 laminated on a substrate such as a flow channel substrate 100 in which a liquid chamber such as a pressurized liquid chamber 4 is formed and which constitutes a part of the wall surface of the liquid chamber, a piezoelectric element 5 laminated on the side of the vibrating membrane 103 opposite to the side that constitutes the wall surface of the liquid chamber, lead wires 9a and 9b drawn out from the piezoelectric element 5 and supplying power to the piezoelectric element 5, and a moisture-proof film 11 covering the lead wires 9a and 9b, the piezoelectric element 5 is only partially covered by the moisture-proof film 11. Generally, moisture-proof films made of materials such as silicon nitride are dense and hard films. Therefore, covering the entire surface of a piezoelectric element with a moisture-proof film may cause a decrease in the vibration displacement of the piezoelectric element. In contrast, in Embodiment 1, the moisture-proof film covers only the lead wiring and a portion of the piezoelectric element, so the reduction in vibration displacement of the piezoelectric element can be suppressed compared to the case where the entire piezoelectric element is covered with the moisture-proof film.

[0090] (Aspect 2) In embodiment 1, the piezoelectric element 5 is covered with a moisture-proof film 11 only around the lead wires 9a and 9b and around the connection points with the lead wires 9a and 9b, such as contacts 7d and 7e. According to this, as explained using Figure 4, the portion of the piezoelectric element 5 covered by the moisture-proof film 11 can be kept to the absolute minimum, and the reduction in vibrational displacement of the piezoelectric element 5 due to the moisture-proof film 11 can be suppressed.

[0091] (Aspect 3) In embodiment 1, the piezoelectric element 5 has a first electrode 51 laminated on the side of the vibrating membrane 103 opposite to the side that constitutes the wall surface of a liquid chamber such as a pressurized liquid chamber, a piezoelectric portion such as a piezoelectric film 52 laminated on the first electrode 51, and a second electrode 53 laminated on the piezoelectric portion, and at least a portion of the second electrode 53 is covered with a moisture-proof film 11. According to this, as explained using Figure 5, the parts of the piezoelectric element 5 where the piezoelectric film 52 is not laminated, such as the first electrode 51, and the parts where the second electrode 53 of the piezoelectric element is not laminated, are parts that hardly displace during operation. Therefore, even if only a portion of the second electrode 53 is covered with the moisture-proof film 11, the decrease in vibration displacement of the piezoelectric element 5 can be suppressed, and the vibrating film 103 can be vibrated effectively.

[0092] (Aspect 4) In any of embodiments 1 to 3, the vibration region 103a of the vibrating membrane 103 that vibrates due to at least the piezoelectric element 5 is covered with the moisture-proof membrane 11 only around the lead wiring 9a, 9b. According to this, as explained using Figure 6, the Young's modulus of the vibration region 103a can be lowered compared to a configuration in which the entire vibration region 103a is covered by the moisture-proof film 11. As a result, the vibration region 103a can be easily vibrated by the displacement of the piezoelectric element 5, and the vibration efficiency can be increased compared to a configuration in which the entire vibration region 103a is covered by the moisture-proof film 11.

[0093] (Aspect 5) In any of embodiments 1 to 4, the moisture-proof film 11 is a silicon (Si) nitride, or an oxide of one of the following metals: tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), and tungsten (W). According to this, good moisture resistance can be obtained.

[0094] (Aspect 6) In a liquid discharge head equipped with an actuator 110, the actuator 110 discharges liquid from a liquid chamber such as a pressurized liquid chamber 4 from a nozzle 2, and the actuator 110 is one of the actuators from embodiment 1 to 5. According to this, liquid can be successfully discharged from nozzle 2.

[0095] (Aspect 7) In embodiment 6, the actuator 110 is provided with a nozzle. According to this, as described in the embodiment, droplets can be ejected with less force compared to a general unimorph type piezo head (which ejects liquid by vibrating the surface opposite the surface having the nozzle in the liquid chamber), and power consumption of the piezoelectric element 5 can be reduced. In addition, the liquid chamber area can be reduced, making it possible to miniaturize the head. Furthermore, compared to the above-mentioned general unimorph type piezo head, the selection of piezoelectric elements 5 can be increased, making it easy to achieve high nozzle density.

[0096] (Pattern 8) A liquid discharge unit comprising a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and at least one of a main scanning movement mechanism, and a liquid discharge head, wherein the liquid discharge head is a liquid discharge head of either embodiment 6 or 7. According to this, liquid can be successfully discharged from nozzle 2.

[0097] (Aspect 9) A device for discharging liquid has a liquid discharging head according to embodiment 6 or 7, or a liquid discharging unit according to embodiment 8. According to this, liquid can be successfully discharged from nozzle 2.

[0098] (Aspect 10) The method for manufacturing an actuator includes the steps of: laminating a vibrating membrane 103 onto a flow channel substrate 100; forming a piezoelectric element 5 on the vibrating membrane 103; forming lead wires 9a and 9b on the vibrating membrane 103 to supply power to the piezoelectric element 5; and forming a moisture-proof film 11 on the lead wires 9a and 9b and a part of the piezoelectric element 5. According to this, it is possible to manufacture an actuator in which the decrease in vibration displacement of the piezoelectric element 5 is suppressed compared to the case in which the entire piezoelectric element 5 is covered with a moisture-proof film 11. [Explanation of symbols]

[0099] 1: Liquid dispensing head 2: Nozzle 3: Common liquid chamber 4: Pressurized liquid chamber 5: Piezoelectric element 6: Electrical connection pad 7a: First Contact 7b: Second Contact 7c: Third Contact 7d: Fourth Contact 7e: Fifth Contact 8: Insulating film 9a: First pullout wiring 9b: Second lead wire 10: Pad opening 11: Moisture-proof membrane 51:First electrode 52: Piezoelectric film 53:Second electrode 100: Flow channel substrate 101: Drive circuit 102:Wiring section 103: Vibrating membrane 103a: Vibration area 103b: Nozzle forming hole 110: Actuator 111: Nozzle forming section 120: Frame component 403: Carriage 405: Main scanning motor 406: Drive pulley 407: Driven pulley 408: Timing belt 440: Liquid Dispensing Unit 441: Head Tank 493: Main scanning movement mechanism 500:Printing device 505:Printing means 550: Head Unit [Prior art documents] [Patent Documents]

[0100] [Patent Document 1] Patent No. 6310824

Claims

1. A vibrating membrane is laminated on a substrate in which a liquid chamber is formed, and which constitutes a part of the wall surface of the liquid chamber, A piezoelectric element is laminated on the side of the vibrating membrane opposite to the side that forms the wall of the liquid chamber, A lead wire drawn from the piezoelectric element and supplying power to the piezoelectric element, The actuator comprises a moisture-proof membrane that covers the aforementioned wiring, In a liquid discharge head that discharges liquid from a liquid chamber through a nozzle using the actuator, The actuator is provided with the nozzle, The piezoelectric element comprises a first electrode laminated on the side of the vibrating membrane opposite to the side constituting the wall of the liquid chamber, a piezoelectric portion laminated on the first electrode, and a second electrode laminated on the piezoelectric portion. The aforementioned lead wiring comprises a first lead wiring drawn from the first electrode and a second lead wiring drawn from the second electrode. A liquid dispensing head characterized in that only the area around the first lead wire, the area around the second lead wire, the area around the connection point between the first electrode of the piezoelectric element and the first lead wire, and the area around the connection point between the second electrode of the piezoelectric element and the second lead wire are covered with a moisture-proof film.

2. In the liquid discharge head according to Claim 1, A liquid dispensing head characterized in that the moisture-proof film is a silicon (Si) nitride or an oxide of one of the following metals: tantalum (Ta), niobium (Nb), titanium (Ti), hafnium (Hf), zirconium (Zr), and tungsten (W).

3. A liquid discharge unit comprising at least one of a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, and a main scanning movement mechanism, and a liquid discharge head, A liquid dispensing unit characterized in that the liquid dispensing head is the liquid dispensing head described in claim 1.

4. In a device that dispenses liquid, A liquid dispensing device characterized by having a liquid dispensing head as described in claim 1, or a liquid dispensing unit as described in claim 3.

5. The process of laminating a diaphragm onto a substrate, The steps include forming a piezoelectric element on the vibrating membrane, A step of forming a first lead wire electrically connected to the first electrode of the piezoelectric element and a second lead wire electrically connected to the second electrode of the piezoelectric element on the vibrating membrane, A step of forming a moisture-proof film around the first lead wire, around the second lead wire, around the connection point between the first electrode and the first lead wire, and around the connection point between the second electrode of the piezoelectric element and the second lead wire. A step of forming a nozzle forming section for nozzle formation, A method for manufacturing a liquid discharge head, characterized in that an actuator equipped with a nozzle is manufactured by a process of forming a nozzle.

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