Liquid ejection head and liquid ejection device

Abstract

To provide a liquid ejection head and a liquid ejection device that can satisfactorily eject, from nozzles, molten resin or molten metal heated to 130°C or higher.SOLUTION: A liquid ejection head 1 includes: a nozzle plate 110 having nozzles 2; and a flow path substrate 100 having pressure chambers 4 communicating with the nozzles 2. Therein: the nozzle plate 110 includes piezoelectric elements with a Curie point of 350°C or higher or no Curie point; and the nozzle plate 110 is vibrated by driving the piezoelectric elements, causing molten resin or molten metal heated to 130°C or higher to be ejected from the nozzles 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a device for ejecting liquid. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known a liquid ejection head that has a nozzle plate having nozzles and a flow path substrate having pressure chambers communicating with the nozzles, and that drives a piezoelectric element to eject liquid in the pressure chambers from the nozzles.

[0003] Patent Document 1 describes a liquid ejection head that ejects molten solder from a nozzle to form solder bumps on a semiconductor chip or the like. A piezoelectric element is provided on the opposing wall of the pressure chamber facing the nozzle plate, and the opposing wall is vibrated to eject the molten solder from the nozzle. In addition, a heater is provided on the cover member that covers the liquid ejection head, and the solder inside the liquid ejection head is heated to a temperature above its melting point. Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the material of the piezoelectric body, there is a risk that molten resin or molten metal such as solder heated to 130° C. or higher may not be discharged properly from the nozzle. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a liquid ejection head having a nozzle plate with a nozzle and a flow path substrate having a pressure chamber communicating with the nozzle, and which drives a piezoelectric element to eject liquid in the pressure chamber from the nozzle, wherein the nozzle plate has a piezoelectric element with a Curie point of 350°C or higher or no Curie point, and is configured so that the nozzle plate vibrates when the piezoelectric element is driven, and molten resin or molten metal heated to 130°C or higher is ejected from the nozzle. [Effects of the Invention]

[0006] According to the present invention, molten resin or molten metal heated to 130° C. or higher can be discharged well from the nozzle. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a cross-sectional view schematically showing a nozzle vibration type liquid ejection head according to the present embodiment. [Figure 2] FIG. 1 is a perspective view schematically showing a liquid ejection head. [Figure 3] FIG. 2 is an enlarged cross-sectional view of part X in FIG. 1. [Figure 4] FIG. 1 is a schematic diagram illustrating the configuration of a printing apparatus as a device that ejects liquid. [Figure 5] FIG. 2 is a plan view illustrating the main parts of the printing apparatus according to the embodiment. [Figure 6] FIG. 2 is a side view illustrating the main parts of the printing apparatus of the present embodiment. [Figure 7] FIG. 2 is a plan view illustrating a main part of the liquid ejection unit according to the embodiment. [Figure 8] FIG. 2 is a front view illustrating the liquid ejection unit of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] The best mode for carrying out the present invention will be described below with reference to the drawings. Note that a person skilled in the art can easily modify or alter the present invention within the scope of the claims to create other embodiments, and these modifications and alterations are included within the scope of the claims. The following description is an example of the best mode for carrying out the present invention and does not limit the scope of the claims.

[0009] FIG. 1 is a cross-sectional view that schematically shows a nozzle vibration type liquid ejection head according to this embodiment, and FIG. 2 is a perspective view that schematically shows the liquid ejection head. The liquid ejection head 1 includes a nozzle plate 110, a flow path substrate 100, and a frame member 120.

[0010] The nozzle plate 110 is thin-film shaped and has a plurality of nozzles 2 that eject liquid, and piezoelectric elements 5 that serve as annular electromechanical conversion elements that are arranged around the nozzles 2. The flow path substrate 100 has a plurality of pressure chambers 4 (also called individual liquid chambers or pressurized liquid chambers) that communicate with the plurality of nozzles 2. The frame member 120 has a common liquid chamber 3 that serves as a liquid supply chamber that communicates with the plurality of pressure chambers 4. In addition, electrical connection pads 6 are provided on both ends of the liquid ejection head 1 for connection to electrical components such as an external power supply.

[0011] A heater 130 is provided on the outer peripheral surface of the frame member 120. In the liquid ejection head of this embodiment, a metal material such as solder or a resin material that is solid at room temperature is used as the ejection material, and the ejection material in the common liquid chamber 3 is heated to 130°C or higher by the heater 130 provided on the frame member 120, melted, and ejected from the nozzle 2.

[0012] FIG. 3 is an enlarged cross-sectional view of a portion X in FIG. The flow channel substrate 100 is an SOI (Silicon on Insulator) substrate, and has a drive circuit 101 and a wiring layer 102 on the side where the vibrating membrane 103 is formed. The drive circuit 101 is a circuit including transistors, resistors, etc. The wiring layer 102 has a wiring section for applying a drive waveform to the first electrode 51 and a wiring section for applying a drive waveform to the second electrode 53.

[0013] By incorporating the drive circuit into the flow path substrate 100, the number of steps for mounting the drive circuit using a separate substrate can be reduced, and the area of ​​the external connection portion can be reduced, leading to a more compact head. Note that if the drive circuit is not built into the flow path substrate 100, and an opening is provided in the nozzle plate 110 and drive control is performed from the outside, the flow path substrate 100 can be a silicon (SI) substrate, and the wiring layer 102 is not required.

[0014] The nozzle plate 110 has a plurality of nozzles 2 formed therein, and has a vibrating membrane 103, piezoelectric elements 5, and a surface layer (membrane) 111 that covers the piezoelectric elements 5. The material of the vibrating membrane 103 is preferably an inorganic material such as SiO2 (silicon dioxide), SiN (silicon nitride), or metal oxide, from the viewpoints of heat resistance, liquid resistance, and insulating properties. However, to increase displacement, a material with a low Young's modulus is desirable, and considering the difference in linear expansion coefficient with the flow path substrate 100, SiO2 (silicon dioxide) is the most desirable material for the vibrating membrane 103, as this difference is relatively small.

[0015] Like the vibration membrane 103, the surface layer (film) 111 is preferably made of an inorganic material such as SiO2, SiN, or metal oxide from the viewpoint of heat resistance, liquid resistance, and insulation. A liquid-repellent film may be formed on the nozzle surface of this surface layer 111. When liquid is continuously ejected, mist generated simultaneously with the ejection adheres to the nozzle surface. If a large amount of this mist adheres to the nozzle surface, the liquid ejected from the nozzle 2 may be affected by the liquid adhering to the nozzle surface and may deviate from the desired landing position. By forming a liquid-repellent film on the nozzle surface, it is possible to prevent the liquid from adhering to the nozzle surface, and to prevent the liquid ejected from the nozzle 2 from being affected by the liquid adhering to the nozzle surface.

[0016] The piezoelectric element 5 of the nozzle plate 110 has a first electrode 51 (also referred to as a lower electrode), a piezoelectric body 52, and a second electrode 53 (also referred to as an upper electrode). The piezoelectric element 5 is covered with a first insulating film 8a. The first insulating film 8a has insulating properties similar to those of the vibration film 103, and is preferably made of the same material as the vibration film 103, SiO2, because it is desirable that the first insulating film 8a has a small Young's modulus and a linear expansion coefficient similar to that of the constituent material.

[0017] The first insulating film 8a has a third contact 7c formed therein in the form of a hole for electrical connection to the first electrode 51 and a fourth contact 7d formed therein in the form of a hole for electrical connection to the second electrode 53.

[0018] In addition, the first insulating film 8a is formed with a first lead-out wiring 9a that electrically connects the first electrode 51 of the piezoelectric element 5 and the wiring layer 102 of the flow path substrate 100, and a second lead-out wiring 9b that electrically connects the second electrode 53 of the piezoelectric element 5 and the wiring layer 102 of the flow path substrate 100.

[0019] The first extraction wiring 9a is electrically connected to the first electrode 51 via the third contact 7c, and is electrically connected to the wiring layer 102 via the first contact 7a. The second extraction wiring 9b is electrically connected to the second electrode 53 via the fourth contact 7d, and is electrically connected to the wiring layer 102 via the second contact 7b.

[0020] The first lead wiring 9a and the second lead wiring 9b are covered with a second insulating film 8b. For the second insulating film 8b, it is desirable to use SiN, which is widely used as a protective film for semiconductors, to improve reliability against humidity. By having the second insulating film 8b have the dual functions of insulation and moisture resistance, the nozzle plate 110 can be made thinner than when a moisture-proof protective film is formed on the second insulating film 8b. This makes it easier for the vibration film 103 to deform, thereby improving vibration efficiency.

[0021] It is also possible to provide lead wiring portions for the first electrode 51 and the second electrode 53, respectively, and connect them directly to the wiring layer 102 as electrodes via contacts opened in the vibration membrane. Also, an adhesion improving film may be formed on the second insulating film 8b to ensure adhesion with the surface layer 111. Furthermore, the wiring layer 102 is electrically connected to the electrical connection pad 6 via a third contact 7c opened in the vibration membrane 103.

[0022] In this embodiment, a protective film 11 that suppresses contamination from molten metal or molten resin is formed on the inner peripheral surface of the pressure chamber 4. The protective film 11 is made of an inorganic material such as metal oxide, metal nitride, ceramic oxide, ceramic nitride, or carbide-based ceramic. More specifically, Al2O3 (aluminum oxide), SiO2 (silicon dioxide), SiN (silicon nitride), ZrO (zirconium oxide), SiC (silicon carbide), etc. can be used.

[0023] Due to its high piezoelectric properties, PZT (lead zirconate titanate) is widely used as the electrostrictive material for the piezoelectric element in inkjet heads. PZT is a ferroelectric material, possessing electric dipoles that are locally divided into positively and negatively charged areas without the application of an external electric field. However, PZT's Curie point, at which its crystal structure changes and it loses its piezoelectric properties, is generally between 150 and 350°C, limiting the temperature environments in which it can be used. As a result, metals with high melting temperatures cannot be used as ejection materials.

[0024] For this reason, in this embodiment, AlN (aluminum nitride) is used as the electrostrictive material of the piezoelectric body 52. ​​AlN has a melting point of 2000°C or higher and does not have a Curie point, so it can be driven well even in a high-temperature environment.

[0025] Furthermore, in this embodiment, a nozzle vibration method is employed in which a piezoelectric element 5 is disposed on a nozzle plate 110, and the pressure in the pressure chamber 4 is varied by the piezoelectric element 5 of the nozzle plate 110, thereby ejecting the liquid in the pressure chamber from the nozzle. The nozzle vibration method is characterized by being able to eject droplets with less force than a typical unimorph type piezo head (which ejects liquid by vibrating the surface facing a wall portion (nozzle communication wall) having a communication port that communicates with the nozzle of the pressure chamber). Therefore, even if AlN, which has a smaller displacement amount than PZT, is used as the electrostrictive material for the piezoelectric body 52, liquid can be ejected satisfactorily. This allows even a discharge material with a high melting temperature to be melted and discharged.

[0026] Furthermore, by adopting the nozzle vibration method, an opening through which the molten material is supplied from the common liquid chamber can be provided at a location of the pressure chamber facing the nozzle plate. This allows for a higher density arrangement of nozzles compared to a system in which an opening through which the molten material is supplied is provided on the side of the pressure chamber, making it possible to miniaturize the liquid ejection head. This reduces the heat capacity of the liquid ejection head, allowing the ejection material to be efficiently heated to a temperature above its melting point, thereby reducing power consumption.

[0027] Furthermore, using AlN as the electrostrictive material offers the following advantage. Namely, the piezoelectric properties can be improved by aligning the crystal orientation of piezoelectric body 52, and an orientation control layer may be provided between vibrating film 103 and first electrode 51 to control the orientation. When piezoelectric body 52 is made of AlN, using AlN as the orientation control layer also makes it possible to bring the lattice constant of first electrode 51, which is made of Mo, closer to that of AlN. As a result, the crystal orientation of piezoelectric body 52 is aligned, enabling improved piezoelectric properties.

[0028] Furthermore, aluminum nitride (AlN) containing at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, and boron may be used as the electrostrictive material for the piezoelectric body. Specifically, a portion of the aluminum in the aluminum nitride is replaced with at least one of the above materials. This allows the aluminum nitride to contain at least one of the above materials. By replacing a portion of the aluminum in the aluminum nitride as the piezoelectric material with at least one of the above materials, the piezoelectric performance can be improved.

[0029] Furthermore, the electrostrictive material of the piezoelectric body 52 is not limited to aluminum nitride, but may be any electrostrictive material with a Curie point of 350°C or higher, or a highly heat-resistant electrostrictive material with no Curie point. By using an electrostrictive material with a Curie point of 350°C or higher, it is possible to use ejection materials with higher melting temperatures than PZT, and the number of ejectable materials can be increased.

[0030] The flow path substrate 100 and the frame member 120 are bonded together using a bonding agent 140. A metal having a melting temperature higher than that of the ejection material is used as the bonding agent 140. This prevents the bonding agent 140 from melting due to heating of the ejection material.

[0031] Next, an example of a liquid ejection device according to the present invention will be described. FIG. 4 is a schematic diagram of a printing device 300 as a device for ejecting liquid. As shown in FIG. 4, the printing apparatus 300 has a liquid ejection unit 301 having a liquid ejection head 1 and a supply device 302, and a table 320 on which a substrate 310 is placed.

[0032] The supply device 302 has a pellet loading section 302a on which solder pellets are loaded. The solder pellets are supplied from this pellet loading section 302a to the common liquid chamber 3. The solder pellets supplied to the common liquid chamber 3 are heated by a heater 130 to become molten. Note that a heater may be provided in the supply device to supply molten solder to the common liquid chamber 3.

[0033] Liquid discharge unit 301 is configured to be movable left and right in the drawing (hereinafter referred to as the sub-scanning direction) and in a direction perpendicular to the paper surface (hereinafter referred to as the main scanning direction). Then, while this liquid discharge unit is moved in the main scanning direction and the sub-scanning direction, molten solder is discharged from nozzle 2 to form solder bumps at desired positions on substrate 310 on table 320.

[0034] In addition, the liquid ejection unit 301 may be configured to be able to eject liquid from one end to the other end in the main scanning direction, the liquid ejection unit 301 may be fixed, and the substrate 310 may be transported in the sub-scanning direction by a transport device to form solder bumps at desired positions on the substrate 310.

[0035] Next, another example of a printing apparatus as a liquid ejecting apparatus according to the present invention will be described with reference to FIGS. FIG. 5 is an explanatory plan view of the main parts of the printing apparatus of this embodiment. FIG. 6 is an explanatory side view of the main part of the printing apparatus of this example.

[0036] The printing apparatus 500 of this example is a serial type apparatus, and a carriage 403 is moved back and forth in the main scanning direction by a 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 hung between left and right side plates 491A and 491B to movably hold the carriage 403. The main scanning motor 405 then moves the carriage 403 back and forth in the main scanning direction via a timing belt 408 hung between a drive pulley 406 and a driven pulley 407.

[0037] This carriage 403 is equipped with a liquid ejection unit 440 that integrates the liquid ejection head 1 according to the present invention and a head tank 441. The liquid ejection head 1 ejects liquid of each color, for example, yellow (Y), cyan (C), magenta (M), and black (K). The liquid ejection head 1 is mounted with a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward.

[0038] 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 attracts the paper 410 and transports it at a position facing the liquid ejection head 1. The transport belt 412 is an endless belt that is stretched between a transport roller 413 and a tension roller 414. The attraction can be achieved 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.

[0039] Furthermore, a maintenance and recovery mechanism 420 that maintains and recovers the liquid ejection head 1 is disposed on one side of the carriage 403 in the main scanning direction, beside the conveyor belt 412. The maintenance and recovery mechanism 420 is composed of, for example, a cap member 421 that caps the nozzle surface of the liquid ejection head 1, a wiper member 422 that wipes the nozzle surface, and the like. The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the conveyor mechanism 495 are attached to a housing that includes side plates 491A and 491B and a back plate 491C.

[0040] In the printing device 500 configured in this manner, the paper 410 is fed onto the conveyor belt 412 and adsorbed thereon, and the paper 410 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 412. Then, by driving the liquid ejection head 1 in accordance with an image signal while moving the carriage 403 in the main scanning direction, liquid is ejected onto the stationary paper 410 to form an image.

[0041] Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 7 is a plan view illustrating the main parts of the liquid ejection unit of this embodiment.

[0042] This liquid ejection unit 440 is composed of the components that make up the device for ejecting the liquid, including a housing portion consisting of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid ejection head 1.

[0043] It is also possible to configure a liquid discharge unit in which the above-described maintenance and recovery mechanism 420 is further attached to, for example, the side plate 491B of this liquid discharge unit 440.

[0044] Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 8 is an explanatory front view of the liquid discharge unit of this embodiment.

[0045] This liquid discharge unit 440 is composed of a liquid discharge head 1 to which a flow path part 444 is attached, and a tube 456 connected to the flow path part 444 .

[0046] The flow path part 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path part 444. A connector 443 for electrically connecting with the liquid ejection head 1 is provided on the upper part of the flow path part 444.

[0047] In such a printing apparatus 500, by using the liquid ejection head of the present invention, it is possible to use resin ink such as solid ink, which is used by being heated and melted, as the ejection material.

[0048] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and variations are possible within the spirit and scope of the present invention as set forth in the claims.

[0049] In the present application, the liquid to be ejected may have a viscosity and surface tension that allow it to be ejected from the head, and is not particularly limited. However, it is preferable that the viscosity of the liquid be reduced to at least 30 mPa·s or less upon heating. More specifically, the liquid may be a solution, suspension, emulsion, or molten metal such as solder containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant. These liquids can be used, for example, in inkjet inks, surface treatment solutions, liquids for forming components or electronic circuit resist patterns for electronic devices or light-emitting elements, liquids for forming solder bumps, and material liquids for 3D modeling.

[0050] A "liquid ejection unit" is a liquid ejection head integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a liquid ejection head combined with at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device.

[0051] Here, "integrated" includes, for example, a liquid ejection head and a functional part or mechanism that are fixed to each other by fastening, bonding, engaging, etc., or one that is held movably relative to the other. The liquid ejection head, functional part, or mechanism may also be configured to be detachable from each other.

[0052] For example, some liquid ejection units have a liquid ejection head and a head tank integrated together, while others have a liquid ejection head and a head tank integrated together by being connected to each other by a tube, etc. Here, a unit including a filter can be added between the head tank and the liquid ejection head of these liquid ejection units.

[0053] Furthermore, there is a liquid ejection unit in which the liquid ejection head and the carriage are integrated.

[0054] In some liquid ejection units, the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated together. In other liquid ejection units, the liquid ejection head, the carriage, and the main scanning movement mechanism are integrated together.

[0055] Furthermore, there is a liquid ejection unit in which a cap member, which is part of the maintenance and recovery mechanism, is fixed to a carriage on which a liquid ejection head is attached, thereby integrating the liquid ejection head, carriage, and maintenance and recovery mechanism.

[0056] In some liquid ejection units, a tube is connected to a liquid ejection head equipped with a head tank or flow path components, integrating the liquid ejection head with a supply mechanism. Liquid is supplied from a liquid storage source to the liquid ejection head via this tube.

[0057] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0058] Here, the "liquid ejection unit" is described in combination with a liquid ejection head, but the "liquid ejection unit" also includes a head module or head unit that includes the liquid ejection head described above, and that integrates the functional components and mechanisms described above.

[0059] "Liquid ejection devices" include devices that are equipped with a liquid ejection head, a liquid ejection unit, a head module, a head unit, etc., and that eject liquid by driving the liquid ejection head. Liquid ejection devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0060] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0061] For example, examples of "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed from layers of powder in order to create a three-dimensional object (a three-dimensional model).

[0062] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0063] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0064] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0065] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0066] Other examples of "liquid ejecting devices" include treatment liquid application devices that eject treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and spray granulation devices that spray a composition liquid in which raw materials are dispersed through a nozzle to granulate the raw material particles.

[0067] In the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous.

[0068] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and unless otherwise specifically limited in the above description, various modifications and variations are possible within the spirit and scope of the present invention as set forth in the claims.

[0069] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) The liquid ejection head 1 has a nozzle plate 110 having a nozzle 2 and a flow path substrate 100 having a pressure chamber 4 communicating with the nozzle 2, and ejects liquid in the pressure chamber 4 from the nozzle 2 by driving a piezoelectric element 52, the nozzle plate 110 having a piezoelectric element 52 with a Curie point of 350°C or higher or no Curie point, and is configured so that the nozzle plate vibrates when driven by the piezoelectric element 52, and ejects molten resin or molten metal heated to 130°C or higher from the nozzle 2. In a liquid ejection head that ejects a material that is solid at room temperature, such as solder (hereinafter referred to as the ejection material), from a nozzle, the ejection material must be heated to above its melting temperature using a heater. Therefore, the temperature of the piezoelectric element rises when the ejection material is heated above its melting temperature. PZT (lead zirconate titanate), a piezoelectric material with high piezoelectric properties, has a Curie point of 150 to 350°C, at which point its crystal structure changes and it loses its piezoelectricity, limiting the temperature environment in which it can be used. Therefore, when molten resin or molten metal heated to above 130°C is ejected from the nozzle, it may lose its piezoelectricity. Piezoelectric materials include those with a Curie point higher than that of PZT, such as AlN (aluminum nitride), or those without a Curie point, but these piezoelectric materials have poorer piezoelectric properties than PZT. As a result, the configuration of Patent Document 1, in which a piezoelectric body is provided on the opposing wall of the pressure chamber facing the nozzle plate, is unable to generate sufficient pressure, and there is a risk that molten resin or molten metal heated to 130°C or higher will not be ejected from the nozzle properly. In contrast, in the first embodiment, a piezoelectric element is provided on the nozzle plate, and the nozzle plate is vibrated to eject the liquid. This allows the liquid to be ejected from the nozzles with a lower pressure than when the opposing wall of the pressure chamber facing the nozzle plate is vibrated to eject the liquid. Therefore, even if a piezoelectric material with a higher Curie point than PZT or a heat-resistant material such as AlN (aluminum nitride) that does not have a Curie point and does not change its displacement even at high temperatures is used as the piezoelectric material, the liquid can still be ejected from the nozzles with a good ejection. As a result, it is possible to eject molten resin or molten metal with a melting temperature of 130°C or higher with a good ejection.

[0070] (Aspect 2) In the first embodiment, the nozzle plate 110 has a surface layer 111 made of an inorganic material. This allows for improved heat resistance compared to organic materials such as resins, and even when an ejection material with a high melting temperature is used, the nozzle plate will not soften, allowing for good liquid ejection.

[0071] (Aspect 3) In the first or second embodiment, the pressure chamber 4 has an opening on the side facing the nozzle plate 110 through which the liquid is supplied. This allows for a higher density of nozzles and a smaller liquid ejection head than one having an opening through which liquid is supplied on the side wall of the pressure chamber 4, as explained in the embodiment. By making the liquid ejection head smaller, the heat capacity of the liquid ejection head can be reduced, the ejection material can be efficiently heated to a temperature above its melting point, and power consumption can be reduced.

[0072] (Aspect 4) In any of the first to third embodiments, a protective layer such as the protective film 11 made of an inorganic material is provided on the inner peripheral surface of the pressure chamber 4 . According to this, as explained in the embodiment, it is possible to protect the sidewall of the flow path substrate 100 that forms the pressure chamber 4 from contamination by the ejection material, such as elution by the molten ejection material.

[0073] (Aspect 5) In the fourth embodiment, the protective layer such as the protective film 11 is made of a metal oxide, a metal nitride, a ceramic oxide, a ceramic nitride, or a carbide-based ceramic. This effectively prevents corrosion and erosion of the molten ejection material, and effectively protects the flow path substrate 100 that forms the pressure chambers 4.

[0074] (Aspect 6) In any of the first to fifth embodiments, the piezoelectric body 52 is aluminum nitride or aluminum nitride containing at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, and boron. This makes it possible to improve the heat resistance of the piezoelectric body 52, as described in the embodiment. As a result, even if the temperature of the piezoelectric body rises due to the heated liquid in the pressure chamber or the heater, the piezoelectric body can be deformed satisfactorily, and the liquid can be ejected satisfactorily from the nozzle.

[0075] (Aspect 7) In any of aspects 1 to 6, the flow path substrate 100 and a substrate such as a frame member 120 having a supply liquid chamber such as a common liquid chamber 3 that supplies liquid to the pressure chamber 4 are joined with a metal having a melting temperature equal to or higher than the melting temperature of the molten resin or molten metal. This can prevent the metal that joins the flow path substrate 100 and the substrate such as the frame member 120 from melting due to heating of the discharge material.

[0076] (Aspect 8) In any of the first to seventh aspects, a plurality of nozzles 14 and pressure chambers 4 are provided. This allows molten metal or molten resin to be ejected from a plurality of nozzles.

[0077] (Aspect 9) In any of the first to eighth aspects, the liquid ejected from the nozzle is a molten metal, and the molten metal is solder. This allows solder bumps to be formed on the substrate as described in the embodiment.

[0078] (Aspect 10) In a liquid ejection device equipped with a liquid ejection head, the liquid ejection head according to any one of the first to ninth embodiments was used as the liquid ejection head. This allows solid ejection materials such as resins and metals to be melted and ejected in a room temperature environment. [Explanation of symbols]

[0079] 1: Liquid ejection head 2: Nozzle 3: Common liquid chamber 4: Pressure chamber 5: Piezoelectric element 6: Electrical connection pad 7a: First Contact 7b: Second Contact 7c: Third Contact 7d: Fourth Contact 8a: First insulating film 8b: second insulating film 9a: First lead-out wiring 9b: Second lead-out wiring 11:Protective film 14: Nozzle 51:First electrode 52: Piezoelectric material 53:Second electrode 100: Flow channel substrate 101: Drive circuit 102: Wiring layer 103: Vibration membrane 110: Nozzle plate 111: Surface layer 120: Frame member 130: Heater 140: Bonding agent 300:Printing device 301: Liquid discharge unit 302: Feeding device 302a: Pellet loading section 310: Substrate 320: Table 440: Liquid dispensing unit 500:Printing device [Prior art documents] [Patent documents]

[0080] [Patent Document 1] Patent No. 4142800

Claims

1. a nozzle plate having nozzles; a flow path substrate having a pressure chamber communicating with the nozzle; a liquid ejection head that drives a piezoelectric body to eject liquid in the pressure chamber from the nozzle, the nozzle plate has a piezoelectric body having a Curie point of 350° C. or higher or no Curie point, and is configured so that the nozzle plate vibrates when the piezoelectric body is driven; A liquid ejection head characterized in that molten resin or molten metal heated to 130° C. or higher is ejected from the nozzle.

2. 2. The liquid ejection head according to claim 1, The liquid ejection head is characterized in that the nozzle plate has a surface layer made of an inorganic material.

3. 2. The liquid ejection head according to claim 1, A liquid ejection head comprising an opening through which liquid is supplied, the opening being located on the side of the pressure chamber facing the nozzle plate.

4. 2. The liquid ejection head according to claim 1, A liquid ejection head characterized in that a protective layer made of an inorganic material is provided on the inner peripheral surface of the pressure chamber.

5. 5. The liquid ejection head according to claim 4, The liquid ejection head is characterized in that the protective layer is made of metal oxide, metal nitride, ceramic oxide, ceramic nitride, or carbide-based ceramic.

6. 2. The liquid ejection head according to claim 1, A liquid ejection head, wherein the piezoelectric body is aluminum nitride or aluminum nitride containing at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, and boron.

7. 2. The liquid ejection head according to claim 1, A liquid ejection head characterized in that the flow path substrate and a substrate having a supply liquid chamber that supplies liquid to the pressure chamber are joined by a metal having a melting temperature higher than the melting temperature of the molten resin or the molten metal.

8. 2. The liquid ejection head according to claim 1, A liquid ejection head comprising a plurality of the nozzles and the pressure chambers.

9. 2. The liquid ejection head according to claim 1, the liquid ejected from the nozzle is a molten metal, The liquid ejection head is characterized in that the molten metal is solder.

10. In a liquid ejection device equipped with a liquid ejection head, 10. A liquid ejection device, comprising: a liquid ejection head according to claim 1;

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