Liquid discharge head and liquid discharge apparatus

Abstract

]A liquid discharge head includes a nozzle plate, a pressure chamber substrate, a piezoelectric element, and a heater. The nozzle plate has a nozzle. The pressure chamber substrate is disposed over the nozzle plate. The pressure chamber substrate has a pressure chamber communicating with the nozzle. The piezoelectric element is disposed in a portion of the nozzle plate facing the pressure chamber. The piezoelectric element surrounds the nozzle and is driven to deform the nozzle plate to discharge the liquid in the pressure chamber from the nozzle in a liquid discharge direction. The heater is disposed in the portion of the nozzle plate facing the pressure chamber. The heater surrounds the nozzle to heat the liquid in the pressure chamber.

Description

[DESCRIPTION][Title of Invention]LIQUID DISCHARGE HEAD AND LIQUID DISCHARGE APPARATUS [Technical Field]

[0001] The present disclosure relates to a liquid discharge head and a liquid discharge apparatus.Related Art[Background Art]

[0002] In the related art, a liquid discharge head drives a piezoelectric body to discharge a liquid from a nozzle. PTL 1 describes a liquid discharge head that discharges molten solder from a nozzle to form a solder bump on, for example, a semiconductor chip. The piezoelectric body is disposed on an opposing wall of a pressure chamber opposed to a nozzle forming wall, and the molten solder is discharged from the nozzle by vibrating the opposing wall. A heater is disposed on a cover that covers the liquid discharge head to heat the solder inside the liquid discharge head to a temperature equal to or higher than the melting temperature.[Citation List][Patent Literature]

[0003] [PTL 1]Japanese Patent No. 4138266[Summary of Invention][Technical Problem]

[0004] However, in PTL 1, materials that can be discharged may be limited. Further, the heater having a large heater capacity may increase the size of the apparatus.[Solution to Problem]

[0005] A liquid discharge head includes a nozzle plate, a pressure chamber substrate, a piezoelectric element, and a heater. The nozzle plate has a nozzle. The pressure chamber substrate is disposed over the nozzle plate. The pressure chamber substrate has a pressure chamber communicating with the nozzle. The piezoelectric element is disposed in a portion of the nozzle plate facing the pressure chamber. The piezoelectric element surrounds the nozzle and is driven to deform the nozzle plate to discharge the liquid in the pressure chamber from the nozzle in a liquid discharge direction. The heater is disposed in the portion of the nozzle plate facing the pressure chamber. The heater surrounds the nozzle to heat the liquid in the pressure chamber.[Advantageous Effects of Invention]

[0006] According to one aspect of the present disclosure, a liquid discharge head (apparatus) can discharge a material having a high melting temperature and can be downsized.[Brief Description of Drawings]

[0007] A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings.[FIG. 1]FIG. 1 is a schematic perspective view of a nozzle face of a liquid discharge head.[FIG. 2]FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1.[FIGS. 3 A and 3B]FIGS. 3 A and 3B are diagrams each illustrating a patterning of a heat generating portion of a heater.[FIG. 4]FIG. 4 is a block diagram illustrating a sequence of temperature control of a heater.[FIG. 5]FIG. 5 is a cross-sectional view of a liquid discharge head according to a modification.[FIG. 6]FIG. 6 is a diagram illustrating processes of forming a wiring layer and a vibration film over a channel substrate.[FIG. 7]FIG. 7 is a diagram illustrating a process of forming a heater.[FIG. 8]FIG. 8 is a diagram illustrating processes of forming a first electrode layer, a piezoelectric layer, and a second electrode layer.[FIG. 9]FIG. 9 is a diagram illustrating a process of forming a first insulating film.[FIG. 10]FIG. 10 is a diagram illustrating a process of forming multiple contacts.[FIG. 11]FIG. 11 is a diagram illustrating a process of forming leads.[FIG. 12]FIG. 12 is a diagram illustrating a process of forming a second insulating film.[FIG. 13]FIG. 13 is a diagram illustrating a process of forming a nozzle forming portion.[FIG. 14]FIG. 14 is a diagram illustrating a process of forming a nozzle.[FIG. 15]FIG. 15 is a diagram illustrating a process of forming a pressure chamber. [FIG. 16]FIG. 16 is a schematic view of a printer.[FIG. 17]FIG. 17 is a schematic plan view of a part of another printer.[FIG. 18]FIG. 18 is a schematic side view of the part of the printer of FIG. 17.[FIG. 19]FIG. 19 is a schematic plan view of a part of a liquid discharge unit. [FIG. 20]FIG. 20 is a schematic front view of a part of another liquid discharge unit.The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views. [Description of Embodiments]

[0008] In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0009] Embodiments of the present disclosure are described below with reference to the drawings. It is to be understood that those skilled in the art can easily modify and change the present disclosure within the scope of the appended claims to form other embodiments, and these modifications and changes are included in the scope of the appended claims. The following embodiments are illustrative and do not limit the scope of the appended claims.

[0010] FIG. 1 is a schematic perspective view of a nozzle face of a liquid discharge head, and FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1.A liquid discharge head 1 includes a nozzle plate 110 and a pressure chamber substrate 100. The nozzle plate 110 is a thin film and includes multiple nozzles 2 for discharging a liquid, a piezoelectric element 5 as an annular electromechanical transducer element disposed around each nozzle 2, and a heater 20.

[0011] The pressure chamber substrate 100 has multiple pressure chambers 4, which may be referred to as individual liquid chambers or pressurization chambers. The multiple pressure chambers 4 communicate with the multiple nozzles 2, respectively. The nozzle 2 and a vibration film 103 are disposed on one side of the pressure chamber 4, and an opening 4a of the pressure chamber 4 is disposed on the other side of the pressure chamber 4.The nozzle plate 110 and the pressure chamber substrate 100 are formed and processed by a semiconductor manufacturing technique. The pressure chambers 4, the nozzles 2, the piezoelectric elements 5, and the heaters 20 are mounted at a high density at a semiconductor wafer level.

[0012] The pressure chamber substrate 100 is a silicon on insulator (SOI) substrate. The pressure chamber substrate 100 includes a drive circuit and a wiring layer 102 on a side on which the vibration film 103 is formed. The drive circuit includes a transistor and a resistor. The wiring layer 102 includes a wiring for applying a drive waveform to a first electrode 51 and a wiring for applying the drive waveform to a second electrode 53. The wiring layer 102 further includes a wiring for applying a voltage to a heat generating portion 21 of the heater 20 and a wiring for applying a voltage to a temperature sensor 22 for sensing the temperature of the heater 20.

[0013] By forming the drive circuit in the pressure chamber substrate 100, a process of mounting the drive circuit using another substrate can be omitted, and the area of an external connection portion can be reduced, which leads to the downsizing of the liquid discharge head 1. When the drive circuit is not built in the pressure chamber substrate 100, and an opening is formed in the nozzle plate 110 to perform drive control from the outside, the pressure chamber substrate 100 may be a silicon substrate without the wiring layer 102.

[0014] The nozzle plate 110 includes a nozzle forming portion (film) 111. The multiple nozzles 2 are formed in the nozzle forming portion 111, and the piezoelectric element 5 is covered with the nozzle forming portion 111. A liquid-repellent film may be formed on a nozzle face of the nozzle forming portion 111.When liquid is consecutively discharged, a mist generated simultaneously with the discharge of the liquid adheres to the nozzle face. When a large amount of mist adheres to the nozzle face, the liquid discharged from the nozzle 2 may be affected by the liquid adhering to the nozzle face and may be deviated from a desired landing position. The liquid-repellent film on the nozzle face prevents liquid from adhering to the nozzle face. Accordingly, liquid discharged from the nozzle 2 is not affected by the liquid adhering to the nozzle face.

[0015] The piezoelectric element 5 of the nozzle plate 110 includes the first electrode 51, a piezoelectric body 52, and the second electrode 53. The first electrode 51 may be referred toas a lower electrode, and the second electrode 53 may be referred to as an upper electrode. The piezoelectric element 5 is covered with a first insulating film 8a. The first insulating film 8a has a hole-shaped third contact 7c through which the first electrode 51 and a first lead 9a are electrically connected, and a hole-shaped fourth contact 7d through which the second electrode 53 and a second lead 9b are electrically connected.

[0016] The first lead 9a is disposed on the first insulating film 8a to electrically connect the first electrode 51 of the piezoelectric element 5 and the wiring layer 102 of the pressure chamber substrate 100. The second lead 9b is disposed on the first insulating film 8a to electrically connect the second electrode 53 of the piezoelectric element 5 and the wiring layer 102 of the pressure chamber substrate 100.

[0017] The first lead 9a is electrically connected to the first electrode 51 through the third contact 7c and to the wiring layer 102 through a first contact 7a. The second lead 9b is electrically connected to the second electrode 53 through the fourth contact 7d and to the wiring layer 102 through a second contact 7b. The first lead 9a and the second lead 9b are covered with a second insulating film 8b. In the present embodiment, the second insulating film 8b also covers the piezoelectric element 5 and prevents moisture that has entered the nozzle forming portion 111 made of resin from reaching the piezoelectric element 5 to protect the piezoelectric element 5.

[0018] The first electrode 51 and the second electrode 53 may be provided with respective lead-out wiring portions, and directly and electrically connected to the wiring layer 102 through contacts opened in the vibration film 103. In addition, an adhesion enhancement film for enhancing the adhesiveness to the nozzle forming portion 111 may be formed on the second insulating film 8b.

[0019] The heater 20 is disposed between the vibration film 103 and the piezoelectric element 5, and includes the heat generating portion 21, the temperature sensor 22, and an insulating film 23. Examples of material for the heat generating portion 21 include molybdenum (Mo) and platinum (Pt). By using Mo or Pt as the heat generating portion 21, efficient heating can be performed with high resistivity.

[0020] The outer end of the heat generating portion 21 (the position farthest from the nozzle 2) is positioned at substantially the same position as the outer end of the first electrode 51 having the largest area of the piezoelectric element 5. Accordingly, the heat generating area of the heater 20 is the maximum area of the piezoelectric element 5 (i.e., equal to the area of the first electrode 51), and corresponds to the cross-sectional area of the pressure chamber 4 in a plane orthogonal to a liquid discharge direction. Thus, the liquid in the pressure chamber 4 can beuniformly heated.

[0021] Further, when the temperature sensor 22 is formed of Pt, the heat generating portion 21 and the temperature sensor 22 can be formed on the same face (i.e., in the same layer of the nozzle plate 110) at the same time by using Pt as the material for the heat generating portion 21. By using Pt as the temperature sensor 22, a temperature can be detected by using a positive temperature coefficient of Pt. Thus, the heater 20 can be feedback-controlled based on the temperature detected by the temperature sensor 22, and the temperature can be precisely controlled. The heater 20 has a thickness of 1 pm and is formed by a thin film formation process.

[0022] In the liquid discharge head of the present embodiment, a metal material such as solder, a material that is solid at room temperature such as wax ink, or a liquid having a high viscosity at room temperature such as ultraviolet (UV) ink is used as a discharge material to be discharged from the nozzle 2. Specifically, the discharge material that is solid at room temperature is heated to a temperature equal to or higher than the melting temperature, and the liquid having a high viscosity at room temperature is heated to a temperature equal to or higher than a temperature at which the viscosity becomes equal to or lower than a predetermined viscosity to be discharged from the nozzle 2. As described above, the heater 20 provided for the nozzle plate 110 allows the discharge material in the pressure chamber 4 to melt or to be less viscous. As a result, the discharge material (liquid) can be favorably discharged from the nozzle 2. In addition, since the nozzle plate 110 can be heated, the liquid adhering to the nozzle face can be prevented from being solidified.

[0023] The heater 20 may be formed on partition walls of the pressure chamber substrate 100 that partition the pressure chamber 4.Thus, the discharge material in the pressure chamber 4 can be maintained at a temperature equal to or higher than the melting temperature or a temperature equal to or higher than a temperature at which the viscosity becomes equal to or lower than the predetermined viscosity, compared to a configuration in which the heater is formed only in the nozzle plate 110.

[0024] FIGS. 3 A and 3B are diagrams each illustrating a patterning of the heat generating portion 21 of the heater 20.The heat generating portion 21 is patterned in a spiral shape as illustrated in FIG. 3 A. Alternatively, the entire surface of the heater 20 at a position corresponding to the pressure chamber 4 may be used as the heat generating portion 21 as illustrated in FIG. 3B. In the configuration illustrated in FIG. 3A, although the heating efficiency is lower than that in the configuration illustrated in FIG. 3B, the thickness of the vibration portion of the vibration film103 can be partially reduced as compared with the configuration illustrated in FIG. 3B, and thus the displacement amount of the vibration film 103 can be increased. On the other hand, when the entire surface of the heater 20 at a position corresponding to the pressure chamber 4 is the heat generating portion 21 as illustrated in FIG. 3B, the heating efficiency can be increased as compared with the spiral pattern illustrated in FIG. 3A.As illustrated in FIGS. 3 A and 3B, the temperature sensor 22 is closer to the nozzle 2 than the heat generating portion 21, and is patterned in an annular shape.

[0025] Multiple annular heat generating portions 21 may be concentrically formed. These multiple heat generating portions 21 may be individually controlled, and for example, only the heat generating portion 21 in the vicinity of the nozzle 2 may generate heat during head cleaning to melt and remove the liquid fixed in the vicinity of the nozzle 2.

[0026] FIG. 4 is a block diagram illustrating a sequence of temperature control of the heater 20. As illustrated in FIG. 4, the temperature sensor 22 inputs an output value (current value) corresponding to the temperature of the liquid to be controlled in the pressure chamber 4 (or in the nozzle 2) to an input unit 25c of a temperature adjuster 25 as an observed value. The temperature of the liquid in the pressure chamber 4 (or in the nozzle 2) is detected based on the observed value of the temperature sensor 22 input to the input unit 25c, and the detected temperature is compared with the target temperature in a comparison unit 25d. Then, the difference value between the target temperature and the detected temperature is calculated by the comparison unit 25d, and the difference value is output to an adjustment unit 25a. The adjustment unit 25a sets a power value (operation amount) to be input to the heat generating portion 21 as an operation unit by proportional-integral-derivative (PID) control. Then, the power value as the operation amount is input to the heat generating portion 21 via an output unit 25b, and the liquid in the pressure chamber 4 as a control target is controlled to a desired temperature.

[0027] The piezoelectric body 52 is heated by the heater 20, and the temperature of the piezoelectric body 52 rises. When the discharge material is a metal material such as solder, the discharge material (liquid) in the pressure chamber 4 is maintained at a temperature of approximately 220°C or more by the heater 20, and thus the temperature of the heat generating portion 21 of the heater 20 becomes 300°C or more. As a result, the piezoelectric body 52 of the nozzle plate 110 is exposed to a high temperature of at least 220°C or more.

[0028] Lead zirconate titanate (PZT) is common in an electro strictive material of a piezoelectric body of an inkjet head because of high piezoelectric property. PZT is a ferroelectric substance and has an electric dipole in which the substance is locally divided into a portion having a positive charge and a portion having a negative charge even when an electric field is not applied fromthe outside. However, the ferroelectric substance such as PZT loses a piezoelectric property by depolarization at a high temperature of 200°C or more, and the piezoelectric body is not displaced.

[0029] For this reason, aluminum nitride (AIN) is used as the electro strictive material for the piezoelectric body 52. Since the displacement amount of AIN does not change even at a high temperature, the piezoelectric body 52 can be driven well even when exposed to a high temperature of 220 °C or more.

[0030] In addition, a nozzle vibration system is adopted in which the piezoelectric element 5 is disposed in the nozzle plate 110, and the liquid in the pressure chamber 4 is discharged from the nozzle 2 by changing the pressure of the liquid in the pressure chamber 4 using the piezoelectric element 5 of the nozzle plate 110. In the nozzle vibration system, a liquid droplet can be discharged with a smaller power than a typical unimorph-type piezoelectric head which vibrates a face of the pressure chamber opposed to a wall (nozzle communication wall) having a communication opening communicating with the nozzle to discharge liquid. Accordingly, even when AIN having a displacement amount smaller than that of PZT is used as the electro strictive material of the piezoelectric body 52, the liquid can be favorably discharged.

[0031] Thus, even a discharge material having a high melting temperature such as solder can be melted and discharged. In an apparatus using the electro strictive material having low heat resistance, for example, the piezoelectric body 52 is insulated with a heat insulating material from heat from the heater 20 or the melted discharge material so that the piezoelectric body 52 does not become high temperature. The apparatus using AIN having high heat resistance can be downsized without a heat insulating material.

[0032] Further, when AIN that has high heat resistance and does not change the displacement amount even at high temperature is used as the electrostrictive material of the piezoelectric body 52, the heater 20 can be formed in the nozzle plate 110. Thus, the discharge material in the pressure chamber 4 can be efficiently heated, and the discharge material in the pressure chamber 4 can be maintained at a temperature equal to or higher than the melting temperature with a small heater capacity. Thus, the power consumption of the apparatus can be reduced. Further, the heater 20 can be downsized, and the increase in size of the apparatus can be prevented.

[0033] Further, the nozzle plate 110 and the pressure chamber substrate 100 are formed and processed by a semiconductor manufacturing technique, and the pressure chambers 4, the nozzles 2, the piezoelectric elements 5, and the heaters 20 are mounted in a thin film shape ata high density at a semiconductor wafer level. Accordingly, the liquid discharge head can be downsized, and the thermal capacity of the liquid discharge head can be reduced.Accordingly, the discharge material in the pressure chamber 4 can be heated more efficiently.

[0034] AIN as the electrostrictive material provides the following advantages. The piezoelectric body 52 in which a crystal orientation is aligned can enhance the piezoelectric property thereof. An orientation control layer may be formed between the vibration film 103 and the first electrode 51 in order to control the crystal orientation. When the electrostrictive material of the piezoelectric body 52 is AIN, a lattice constant of the first electrode 51 made of Mo can be closer to that of AIN by using AIN as the orientation control layer. As a result, the crystal orientation of the piezoelectric body 52 is aligned to enhance the piezoelectric property.

[0035] Further, AIN including at least one material of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, or boron may be used as the electrostrictive material of the piezoelectric body 52. Specifically, aluminum (Al) in a part of AIN is substituted with at least one of the above materials. Thus, AIN can include at least one of the above materials. AIN as the electrostrictive material in which Al in a part of AIN is substituted with at least one of the above materials can enhance the piezoelectric property. The electrostrictive material for the piezoelectric body 52 is not limited to AIN, and any electrostrictive material that has high heat resistance and does not change the displacement amount even in a high- temperature environment can be used.

[0036] FIG. 5 is a cross-sectional view of a liquid discharge head according to a modification. In a liquid discharge head la according to the present modification, the nozzle plate 110 includes the vibration film 103, the piezoelectric element 5, and the heater 20 in this order from the pressure chamber 4. In this modification, since the piezoelectric element 5 is formed on the vibration film 103, the vibration film 103 can be favorably vibrated, and the displacement amount of the vibration film 103 can be increased.

[0037] On the other hand, in the liquid discharge head 1 illustrated in FIG. 2, the heater 20 is closer to the pressure chamber 4 than in the liquid discharge head la of the present modification, and thus the discharge material in the pressure chamber 4 can be efficiently heated. Thus, the amount of heat generated by the heat generating portion 21 can be reduced, and the discharge material in the pressure chamber 4 can be maintained at a temperature equal to or higher than the melting temperature or a temperature at which the viscosity becomes equal to or lower than a predetermined viscosity to reduce power consumption.

[0038] Alternatively, multiple heaters may be formed in the nozzle plate 110 such that the vibration film 103, an inner-side heater, the piezoelectric element 5, and an outer-side heater arearranged in this order from the pressure chamber 4. The outer heater is provided with a heat generating portion only in the vicinity of the nozzle, and the vicinity of the nozzle is heated by the outer heater at the time of cleaning the head to melt and remove the liquid fixed to the vicinity of the nozzle.

[0039] A method of manufacturing the liquid discharge head is described below.The liquid discharge head of the present embodiment achieves high-density mounting with low cost by forming and processing the pressure chamber 4, the nozzle 2, the piezoelectric element 5, and the heater 20 by a semiconductor manufacturing process.FIGS. 6 to 15 are cross-sectional views of the liquid discharge head taken in the direction orthogonal to the arrangement direction of the nozzle holes, illustrating the manufacturing process of the liquid discharge head manufactured by the semiconductor manufacturing process.

[0040] As illustrated in FIG. 6, the drive circuit including a transistor and a resistor, and the wiring layer 102 are formed over a silicon film of the pressure chamber substrate 100 as the SOI substrate. The wiring layer 102 is formed by, for example, a damascene method in which a silicon dioxide (SiO2) film is formed and patterned to form a groove, and the groove is filled with a wiring metal. The wiring metal in the groove is covered with a SiO2 film. The above processes are repeated. Specifically, the wiring metal is flattened by chemical mechanical polishing (CMP), the SiO2 film is formed thereon and patterned again, and these processes are repeated. As a result, a fine wiring having a three-dimensional structure can be formed.Thus, the wiring for applying a drive waveform to the first electrode 51 and the wiring for applying the drive waveform to the second electrode 53 are formed. Further, the wiring for applying a voltage to the heat generating portion 21 of the heater 20 and the wiring for applying a voltage to the temperature sensor 22 for sensing the temperature of the heater 20 are formed.

[0041] Then, the vibration film 103 is formed over the surface of the pressure chamber substrate 100 on which the wiring layer 102 is formed.The vibration film 103 may be made of a material having at least an electrical insulation property, such as SiO2, silicon nitride (SiN), metallic oxides, and resins. However, the material for the vibration film 103 preferably has a low Young modulus to increase the displacement amount, and in consideration of the difference in linear expansion coefficient between the material and the pressure chamber substrate 100, SiO2 having a relatively small difference in linear expansion coefficient is most preferable as the material for the vibration film 103.

[0042] Subsequently, as illustrated in FIG. 7, the heater 20 is formed on the vibration film 103.A Pt film is formed on the vibration film 103 by sputtering and processed by photolithography and etching to form the heat generating portion 21 and the temperature sensor 22 of the heater 20 in a desired pattern. Then, the insulating film 23 is formed to complete the heater 20. Thus, the heater 20 can be formed in a portion (i.e. a nozzle forming wall) of the nozzle plate 110 surrounding the nozzle 2 and facing the pressure chamber 4.The heater 20 may be formed by the damascene method as in the case of the wiring layer 102 described above. Specifically, the SiCh film is formed and patterned to form a groove, the groove is filled with Pt, and the groove filled with Pt is covered with SiCh to form the heater 20 on the vibration film 103.

[0043] After that, as illustrated in FIG. 8, a first electrode layer 151, a piezoelectric layer 152, and a second electrode layer 153 are formed over the heater 20. The first electrode layer 151 and the second electrode layer 153 are preferably made of a metal having low electrical resistance and low reactivity, such as Pt, iridium (Ir), or Mo.

[0044] By using AIN as the electro strictive material forming the piezoelectric layer 152, the film formation temperature can be set to 450°C or less. When a drive circuit, i.e., a complementary metal oxide semiconductor (CMOS) circuit, is formed in a portion corresponding to the wiring layer 102, for example, a transistor and a resistor constructing the drive circuit can be prevented from being damaged by heat.

[0045] The first electrode layer 151 and the second electrode layer 153 can be formed by sputtering or sol-gel method. Since the film formation temperature is high in the sol-gel method, when a drive circuit or a wiring portion is built in the pressure chamber substrate 100, the first electrode layer 151 and the second electrode layer 153 are preferably formed by sputtering.

[0046] After the film formation, the first electrode layer 151, the piezoelectric layer 152, and the second electrode layer 153 are formed into desired shapes as illustrated in FIG. 9 to obtain the piezoelectric element 5 including the first electrode 51, the piezoelectric body 52, and the second electrode 53. The first electrode layer 151, the piezoelectric layer 152, and the second electrode layer 153 are processed by photolithography and etching to obtain the first electrode 51, the piezoelectric body 52, and the second electrode 53 having the desired shapes. The etching includes wet etching and dry etching, but dry etching is preferable in order to prevent corrosion of the first electrode 51, the second electrode 53, and the piezoelectric body 52. After the dry etching, a residue due to the processing of the dry etching is likely to remain. For this reason, a cleaning process may be performed to remove the residue after the first electrode 51, the piezoelectric body 52, and the second electrode 53 are formed.

[0047] After the first electrode 51, the piezoelectric body 52, and the second electrode 53 are formed,the first insulating film 8a is formed as illustrated in FIG. 9. Similarly to the vibration film 103, the first insulating film 8a preferably has the electrical insulation property, a low Young modulus, and a linear expansion coefficient close to that of other components. Specifically, SiCh, which is the same material as that of the vibration film 103, is preferable. In addition, in order to enhance reliability, very thin metallic oxide may be used as the material for the first insulating film 8a.

[0048] After the first insulating film 8a is formed, as illustrated in FIG. 10, the hole-shaped third contact 7c and fourth contact 7d are formed in the first insulating film 8a by photolithography and etching. In addition, the hole- shaped first contact 7a and second contact 7b penetrating the vibration film 103 and the insulating film 23 of the heater 20 are formed.

[0049] Then, as illustrated in FIG. 11, the first lead 9a and the second lead 9b are formed. The material for the first lead 9a and the second lead 9b is typically Al or aluminum-copper (Al- Cu) alloys, but noble metals may be used for enhancing reliability. By this process, the first lead 9a is electrically connected to the first electrode 51 through the third contact 7c and to the wiring layer 102 through the first contact 7a. The second lead 9b is electrically connected to the second electrode 53 through the fourth contact 7d and to the wiring layer 102 through the second contact 7b.

[0050] Subsequently, as illustrated in FIG. 12, the second insulating film 8b is formed so as to cover the first lead 9a, the second lead 9b, and the piezoelectric element 5. Although SiO2 may be used for the second insulating film 8b similarly to the first insulating film 8a, SiN having moisture resistance is preferable, which is common in a protective film for semiconductors, in order to enhance reliability against moisture. Since the second insulating film 8b has two functions of the electrical insulation and moisture-proof properties, the nozzle plate 110 can be thinned compared to when a moisture-proof protective film is formed over the second insulating film 8b.The piezoelectric element 5 to be driven can be completed by the above processes. Thus, the piezoelectric element 5 can be formed in the portion (i.e., the nozzle forming wall) of the nozzle plate 110 surrounding the nozzle 2 and facing the pressure chamber 4.

[0051] As illustrated in FIG. 13, the nozzle forming portion 111 for forming the nozzle 2 is formed. The nozzle forming portion 111 is formed by spin coating. The material for the nozzle forming portion 111 is preferably resins that can be applied by spin coating. For example, epoxy resin SU-8 and benzcyclobutene (BCB) are preferable from the viewpoint of chemical resistance.Then, as illustrated in FIG. 14, the nozzle 2 is formed by etching. The nozzle 2 is formed by dry etching.Lastly, as illustrated in FIG. 15, the pressure chamber substrate 100 is processed by Si etching to form multiple pressure chambers 4 in a circular hole shape to complete the liquid discharge head 1.With such a configuration, as the piezoelectric element 5 is driven, the nozzle plate 110 is deformed. As a result, the pressure of the liquid in the pressure chamber 4 is changed, and the liquid in the pressure chamber 4 is discharged from the nozzle 2 in the liquid discharge direction.

[0052] A liquid discharge apparatus is described below.FIG. 16 is a schematic diagram illustrating a configuration of a printer 300 as a liquid discharge apparatus.As illustrated in FIG. 16, the printer 300 includes a liquid discharge unit 301 and a table 320. The liquid discharge unit 301 includes the liquid discharge head 1 and a supply device 302. A substrate 310 (i.e., a medium) is placed on the table 320.

[0053] The liquid discharge head 1 includes a supply chamber substrate having a common chamber 3 as a supply chamber for supplying molten solder (molten metal) to the respective pressure chambers 4. A heater 3a is disposed on a wall of the common chamber 3. The supply device 302 includes a pellet loader 302a on which solder pellets are loaded. The solder pellets are supplied from the pellet loader 302a to the common chamber 3. The solder pellets supplied to the common chamber 3 are heated by the heater 3 a as a second heater and melted in the common chamber 3 (i.e., molten solder 303). The supply device 302 may be provided with a heater to supply the molten solder 303 to the common chamber 3.

[0054] The liquid discharge unit 301 is movable in the left-right direction in FIG. 16 (may be referred to as a sub-scanning direction) and in a direction orthogonal to the surface of the paper on which FIG. 16 is drawn (may be referred to as a main scanning direction). While the liquid discharge unit 301 moves in the main scanning direction and the sub-scanning direction, the molten solder 303 (i.e., liquid) is discharged from the nozzle 2, and a solder bump is formed at a desired position of the substrate 310 on the table 320.

[0055] The liquid discharge unit 301 may discharge liquid (i.e., molten solder 303) in a range from one end to the other end in the main scanning direction. With such a configuration, the liquid discharge unit 301 may be fixed, and the substrate 310 may be conveyed in the sub-scanning direction by a conveyor to form a solder bump at a desired position on the substrate 310. In the printer 300, solder is used as the discharge material, but solid ink such as wax ink can be used as the discharge material.

[0056] Another printer 500 as a liquid discharge apparatus is described below with reference toFIGS. 17 and 18.FIG. 17 is a plan view of a part of the printer 500. FIG. 18 is a side view of the part of the printer 500 illustrated in FIG. 17.

[0057] The printer 500 is a serial type apparatus, and a main-scanning moving mechanism 493 reciprocally moves a carriage 403 in the main scanning direction. The main-scanning moving mechanism 493 includes a guide 401, a main scanning motor 405, and a timing belt 408. The guide 401 is bridged between left and right side plates 491 A and 49 IB to movably hold the carriage 403.The main scanning motor 405 reciprocates the carriage 403 in the main scanning direction via the timing belt 408 looped around a drive pulley 406 and a driven pulley 407.

[0058] The carriage 403 includes a liquid discharge unit 440 in which the liquid discharge head 1 and a head tank 441 are integrated into a single unit. The liquid discharge head 1 discharges color liquids of, for example, yellow (Y), cyan (C), magenta (M), and black (K).The liquid discharge head 1 is mounted on the liquid discharge unit 440 such that a nozzle row including the multiple nozzles 2 is arranged in the sub-scanning direction orthogonal to the main scanning direction. The liquid discharge head 1 discharges the color liquids downward from the multiple nozzles 2.

[0059] The printer 500 includes a conveyance mechanism 495 to convey a sheet 410 (i.e., a medium). The conveyance mechanism 495 includes a conveyance belt 412 (i.e., a conveyor) and a sub-scanning motor 416 to drive the conveyance belt 412. The conveyance belt 412 attracts the sheet 410 and conveys the sheet 410 at a position facing the liquid discharge head 1. The conveyance belt 412 is an endless belt looped around a conveyance roller 413 and a tension roller 414. The sheet 410 can be attracted to the conveyance belt 412 by, for example, electrostatic attraction or air suction. The conveyance belt 412 circumferentially moves in the sub-scanning direction as the conveyance roller 413 is rotationally driven by the sub-scanning motor 416 via a timing belt 417 and a timing pulley 418.

[0060] On one end of the range of movement of the carriage 403 in the main scanning direction, a maintenance mechanism 420 that maintains and recovers the liquid discharge head 1 is disposed lateral to the conveyance belt 412. The maintenance mechanism 420 includes, for example, a cap 421 to cap the nozzle face of the liquid discharge head 1 and a wiper 422 to wipe the nozzle face. The main-scanning moving mechanism 493, the maintenance mechanism 420, and the conveyance mechanism 495 are mounted onto a housing including the side plates 491 A and 49 IB and a back plate 491C.

[0061] In the printer 500 having the above-described configuration, the sheet 410 is fed and attractedonto the conveyance belt 412 and conveyed in the sub-scanning direction by the circumferential movement of the conveyance belt 412. The liquid discharge head 1 is driven in response to an image signal while the carriage 403 is moved in the main scanning direction to discharge a liquid onto the sheet 410 not in motion to form an image.

[0062] Another liquid discharge unit 440 is described below with reference to FIG. 19.FIG. 19 is a plan view of a part of the liquid discharge unit 440.

[0063] The liquid discharge unit 440 includes the housing, the main-scanning moving mechanism 493, the carriage 403, and the liquid discharge head 1 among components of the printer 500 as the liquid discharge apparatus illustrated in FIG. 17. The side plates 491A and 491B, and the back plate 491C construct the housing.

[0064] In the liquid discharge unit 440, the maintenance mechanism 420 described above may be mounted on, for example, the side plate 49 IB.

[0065] Still another liquid discharge unit 440 is described below with reference to FIG. 20.FIG. 20 is a plan view of a part of the liquid discharge unit 440.

[0066] The liquid discharge unit 440 includes the liquid discharge head 1 to which a channel component 444 is attached, and a tube 456 connected to the channel component 444.

[0067] The channel component 444 is disposed inside a cover 442. Alternatively, the liquid discharge unit 440 may include the head tank 441 instead of the channel component 444. A connector 443 for electrically connecting to the liquid discharge head 1 is disposed on an upper portion of the channel component 444.

[0068] In the printer 500 described above, by using the liquid discharge head according to the present embodiment, various types of ink can be used as the discharge material, such as UV ink whose viscosity is reduced by heating or solid ink which is used by being heated and melted.

[0069] The liquid discharge head according to the present embodiment can also be applied to a printer that prints a wiring pattern on a substrate using a metal ink containing metal nanoparticles as the discharge material. By heating and discharging the metal ink using the liquid discharge head according to the present embodiment, the solvent of the metal ink can be evaporated from the moment the metal ink is discharged onto the substrate, and the metal ink can be prevented from wetting and spreading on the substrate, and thus a fine wiring pattern can be formed.

[0070] The above-described embodiments are illustrative and do not limit the embodiments of the present disclosure. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present disclosure.

[0071] In the present disclosure, the liquid to be discharged is not limited to a particular liquid as long as the liquid has a viscosity or surface tension to be discharged from a head (liquid discharge head). However, preferably, the viscosity of the liquid is not greater than 30 millipascal-second (mPa- s) by heating. Examples of the liquid include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent; a colorant, such as dye or pigment; a functional material, such as a polymerizable compound, a resin, or a surfactant; a biocompatible material, such as deoxyribonucleic acid (DNA), amino acid, protein, or calcium; or an edible material, such as a natural colorant, or molten metal, such as solder. Such a solution, a suspension, an emulsion, or molten metal can be used for, e.g., inkjet ink, surface treatment solution, a liquid for forming components of electronic element or light-emitting element or a resist pattern of electronic circuit, a liquid for forming a solder bump, or a material solution for three-dimensional fabrication.

[0072] The “liquid discharge unit” is an assembly of parts relating to liquid discharge. The term “liquid discharge unit” represents a structure including the liquid discharge head and a functional component(s) or mechanism(s) combined with the liquid discharge head as a single unit. For example, the “liquid discharge unit” includes a combination of the liquid discharge head with at least one of a head tank, a carriage, a supply mechanism, a maintenance mechanism, a main-scanning moving mechanism, or a liquid circulation device.

[0073] The above integration may be achieved by, for example, a combination in which the liquid discharge head and a functional component(s) or mechanism(s) are fixed to each other through, e.g., fastening, bonding, or engaging, and a combination in which one of the liquid discharge head and the functional component(s) or mechanism(s) is movably held to the other. The liquid discharge head and the functional component(s) or mechanism(s) may be detachably attached to each other.

[0074] For example, the liquid discharge head and the head tank are integrated to form the liquid discharge unit as a single unit. Alternatively, the liquid discharge head and the head tank coupled (connected) to each other via, for example, a tube may form the liquid discharge unit as a single unit. A unit including a filter may further be added to a portion between the head tank and the liquid discharge head of the liquid discharge unit.

[0075] In another example, the liquid discharge unit may be an integrated unit in which a liquid discharge head is integrated with a carriage.

[0076] As yet another example, the liquid discharge unit is a unit in which the liquid discharge head and the main-scanning moving mechanism are combined into a single unit. The liquid discharge head is movably held by a guide that is a part of the main- scanning moving mechanism. The liquid discharge unit may include the liquid discharge head, the carriage, and the main-scanning moving mechanism that are integrated as a single unit.

[0077] In another example, the cap that forms a part of the maintenance mechanism is fixed to the carriage mounting the liquid discharge head so that the liquid discharge head, the carriage, and the maintenance mechanism are integrated as a single unit to form the liquid discharge unit.

[0078] Further, in still another example, the liquid discharge unit includes tubes connected to the liquid discharge head mounting the head tank or the channel component so that the liquid discharge head and the supply mechanism are integrated as a single unit. Through the tube, the liquid in a liquid storage source is supplied to the liquid discharge head.

[0079] The main- scanning moving mechanism may be a guide only. The supply mechanism may be a tube(s) only or a loader only.

[0080] The “liquid discharge unit” includes a head module including the above-described liquid discharge head, and a head unit with which the above-described functional components or mechanisms are combined to form a single unit.

[0081] The term “liquid discharge apparatus” used herein also represents an apparatus including the head, the liquid discharge unit, the head module, or the head unit to drive the liquid discharge head to discharge liquid. The liquid discharge apparatus may be, for example, any apparatus that can discharge liquid to a medium onto which liquid can adhere or any apparatus to discharge liquid toward gas or into a different liquid.

[0082] The “liquid discharge apparatus” may further include devices relating to feeding, conveying, and ejecting of the medium onto which liquid can adhere and also include a pretreatment device and an aftertreatment device.

[0083] The “liquid discharge apparatus” may be, for example, an image forming apparatus to form an image on a sheet by discharging ink, or a three-dimensional fabrication apparatus to discharge fabrication liquid to a powder layer in which powder material is formed in layers, so as toform a three-dimensional object.

[0084] The “liquid discharge apparatus” is not limited to an apparatus that discharges liquid to visualize meaningful images such as letters or figures. For example, the liquid discharge apparatus may be an apparatus that forms patterns having no meaning or an apparatus that fabricates three-dimensional images.

[0085] The above-described term “medium onto which liquid can adhere” represents a medium on which liquid is at least temporarily adhered, a medium on which liquid is adhered and fixed, or a medium into which liquid adheres and permeates. Specific examples of the “medium onto which liquid can adhere” include, but are not limited to, a recording medium such as a paper sheet, recording paper, a recording sheet of paper, a film, or cloth, an electronic component such as an electronic substrate or a piezoelectric element, and a medium such as layered powder, an organ model, or a testing cell. The “medium onto which liquid can adhere” includes any medium to which liquid adheres, unless otherwise specified.

[0086] Examples of materials for the “medium onto which liquid can adhere” include any materials to which liquid can adhere even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic.

[0087] The liquid discharge apparatus may be an apparatus to move the liquid discharge head and the medium onto which liquid can adhere relative to each other. However, the liquid discharge apparatus is not limited to such an apparatus. For example, the liquid discharge apparatus may be a serial head apparatus that moves the liquid discharge head or a line head apparatus that does not move the liquid discharge head.

[0088] Examples of the “liquid discharge apparatus” further include a treatment liquid coating apparatus to discharge a treatment liquid to a sheet to coat a surface of the sheet with the treatment liquid to reform the sheet surface. Examples of the “liquid discharge apparatus” further include an injection granulation apparatus in which a composition liquid including raw materials dispersed in a solution is injected through nozzles to granulate fine particles of the raw materials.

[0089] The terms “image formation,” “recording,” “printing,” “image printing,” and “fabricating” used herein may be used synonymously with each other.

[0090] The embodiments described above are just examples, and the various aspects of the present disclosure attain respective effects as follows.Aspect 1A liquid discharge head 1 discharges a liquid from a nozzle 2 by driving a piezoelectric body 52. The piezoelectric body 52 and a heater 20 are disposed in the nozzle forming wall of a pressure chamber 4 communicating with the nozzle 2.In other words, a liquid discharge head includes a nozzle plate, a pressure chamber substrate, a piezoelectric element, and a heater. The nozzle plate has a nozzle. The pressure chamber substrate is disposed over the nozzle plate. The pressure chamber substrate has a pressure chamber communicating with the nozzle. The piezoelectric element is disposed in a portion of the nozzle plate facing the pressure chamber. The piezoelectric element surrounds the nozzle and is driven to deform the nozzle plate to discharge the liquid in the pressure chamber from the nozzle in a liquid discharge direction. The heater is disposed in the portion of the nozzle plate facing the pressure chamber. The heater surrounds the nozzle to heat the liquid in the pressure chamber.In an apparatus for discharging a material (may be referred to as a discharge material in the following description) that is solid at room temperature, such as solder, from a nozzle, the discharge material is heated to a temperature equal to or higher than the melting temperature by a heater. Accordingly, the temperature of the piezoelectric body is increased by the discharge material heated to the melting temperature or higher. When PZT having high piezoelectric property is used as a material for the piezoelectric body, PZT loses the piezoelectric property by depolarization at a high temperature of 200°C or more, and the piezoelectric body is not displaced even when a voltage is applied. Accordingly, the discharge material is limited to a material having a melting temperature of less than 200°C. When a material such as AIN, which does not change the displacement amount even at high temperature, is used as the material for the piezoelectric body, the piezoelectric property is lower than that of PZT. Accordingly, with the configuration according to a comparative example in which the piezoelectric body is disposed in the opposing wall opposed to the nozzle forming wall of the pressure chamber, a sufficient pressure may not be generated, and thus liquid may not be favorably discharged from the nozzle.By contrast, in Aspect 1, the piezoelectric body is disposed in the nozzle forming wall, and the nozzle forming wall having the nozzle of the pressure chamber is vibrated to discharge the liquid. The nozzle forming wall is a portion of the nozzle plate surrounding the nozzle and facing the pressure chamber. Such a configuration can favorably discharge the liquid from the nozzle with a small pressure compared to the configuration in which the liquid is discharged by vibrating the opposing wall opposed to the nozzle forming wall of the pressure chamber. Accordingly, even when a material, which has low piezoelectric property and generates low pressure, but has high heat resistance and does not change the displacement amount even at high temperature, such as AIN, is used as the material for the piezoelectric body, the liquid is favorably discharged from the nozzle. As a result, a material having a high melting temperature can be discharged.Further, the heater disposed in the nozzle forming wall can efficiently heat the dischargematerial in the pressure chamber, and thus the discharge material in the pressure chamber can be maintained at a temperature equal to or higher than the melting temperature with a small heater capacity, as compared with the configuration in which the heater is disposed in the cover covering the liquid discharge head. Thus, the power consumption of the apparatus can be reduced. Further, the heater can be downsized, and the increase in size of the apparatus can be prevented.

[0091] Aspect 2In Aspect 1, the heater 20 is disposed on the pressure chamber 4 side with respect to the piezoelectric body 52.In other words, the heater is closer to the pressure chamber than the piezoelectric element in the liquid discharge direction in the nozzle plate.According to this configuration, as described in the above embodiment, the discharge material in the pressure chamber can be efficiently heated compared to the configuration in which the piezoelectric body 52 is disposed closer to the pressure chamber 4 than the heater 20.

[0092] Aspect 3In Aspect 1, the piezoelectric body 52 is disposed on the pressure chamber 4 side with respect to the heater 20.In other words, the piezoelectric element is closer to the pressure chamber than the heater in the liquid discharge direction in the nozzle plate.According to this configuration, as described with reference to FIG. 5, the vibration film 103 can be vibrated more efficiently than the configuration in which the heater 20 is disposed closer to the pressure chamber 4 than the piezoelectric body 52.

[0093] Aspect 4In any one of Aspects 1 to 3, a heat generating portion 21 of the heater 20 is made of molybdenum or platinum.In other words, the heater has a heat generating portion made of molybdenum or platinum. According to this configuration, as described in the above embodiment, heating can be performed efficiently with high resistivity.

[0094] Aspect 5In any one of Aspects 1 to 4, a temperature sensor 22 is disposed in the nozzle forming wall. In other words, the liquid discharge head according to any one of Aspects 1 to 4, further includes a temperature sensor in the portion of the nozzle plate facing the pressure chamber. The temperature sensor surrounds the nozzle to detect a temperature of the liquid in the pressure chamber.According to this configuration, as described in the above embodiment, the heater 20 can becontrolled based on the temperature sensed by the temperature sensor 22. As a result, the liquid in the pressure chamber 4 can be favorably maintained at the target temperature.

[0095] Aspect 6In Aspect 5, the temperature sensor 22 is formed in the same layer as the heat generating portion 21, and the temperature sensor 22 and the heat generating portion 21 are made of platinum.In other words, the heater has a heat generating portion. The temperature sensor and the heat generating portion are disposed in the same layer of the nozzle plate in the liquid discharge direction. The temperature sensor and the heat generating portion are made of platinum. According to this configuration, the temperature can be accurately detected, and heating can be efficiently performed. Further, the heat generating portion 21 and the temperature sensor 22 can be formed at a time, and the number of manufacturing processes can be reduced.

[0096] Aspect 7In any one of Aspects 1 to 6, the piezoelectric body 52 is aluminum nitride or aluminum nitride containing at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, or boron.In other words, the piezoelectric element includes: aluminum nitride; or aluminum nitride including at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, or boron.According to this configuration, as described in the above embodiment, the heat resistance of the piezoelectric body 52 can be increased. According to this configuration, even when the temperature of the piezoelectric body 52 is increased by the heated liquid in the pressure chamber or the heater, the piezoelectric body 52 is displaced well, and thus the liquid can be favorably discharged from the nozzle.

[0097] Aspect 8In any one of Aspects 1 to 7, a heat generating area of the heater 20 is equal to the maximum cross-sectional area of the piezoelectric element 5 including the piezoelectric body 52. The maximum cross-sectional area is orthogonal to the liquid discharge direction.In other words, the heater has a heat generating area equal to a maximum cross-sectional area, of the piezoelectric element, in a plane orthogonal to the liquid discharge direction.According to this configuration, as described in the above embodiment, the liquid in the pressure chamber can be uniformly heated.

[0098] Aspect 9In any one of Aspects 1 to 8, a second heater 3a is disposed on the wall of a supply chamber such as a common chamber 3 for supplying the liquid to the pressure chamber 4.In other words, the liquid discharge head according to any one of Aspects 1 to 8, further includes a supply chamber substrate having a supply chamber communicating with the pressure chamber, and another heater on a wall of the supply chamber substrate.According to this configuration, as described in the above embodiment, the discharge material which is melted and becomes liquid can be supplied to the pressure chamber 4.

[0099] Aspect 10In any one of the Aspects 1 to 9, the liquid discharged from the nozzle 2 is molten metal such as solder.In other words, the piezoelectric element is driven to deform the nozzle plate to discharge molten metal as the liquid in the pressure chamber from the nozzle in the liquid discharged direction.According to this configuration, as described in the above embodiment, solder bumps and wiring patterns can be formed on the substrate.

[0100] Aspect 11In a liquid discharge apparatus including the liquid discharge head, the liquid discharge head according to any one of Aspects 1 to 10 is used as the liquid discharge head.In other words, a liquid discharge apparatus includes the liquid discharge head according to any one of Aspects 1 to 10, to discharge a liquid onto a medium, and a carriage mounting the liquid discharge head to move the liquid discharge head relative to the medium.According to this configuration, liquid having a high viscosity at room temperature, such as UV ink, can be discharged by lowering the viscosity of the liquid. Further, a solid discharge material such as wax ink or solder can be melted and discharged at room temperature.

[0101] The above-described embodiments are illustrative and do not limit the present invention. Thus, numerous additional modifications and variations are possible in light of the above teachings. For example, elements and / or features of different illustrative embodiments may be combined with each other and / or substituted for each other within the scope of the present invention.

[0102] This patent application is based on and claims priority to Japanese Patent Application No. 2024-007965, filed on January 23, 2024, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.[Reference Signs List]

[0103] 1 : Liquid discharge head2: Nozzle3: Common liquid chambera: Heater : Pressure chamber a: Opening : Piezoelectric element a: First contact b: Second contact c: Third contact d: Fourth contact a: First insulating film b: Second insulating film a: First lead b: Second lead 0: Heater 1: Heat generating portion2: Temperature sensor 3: Insulating film 5: Temperature adjuster 5a: Adjustment unit 5c: Input unit 5d: Comparison unit 1 : First electrode 2: Piezoelectric body 3: Second electrode 00: Pressure chamber substrate02: Wiring layer 03: Vibration film 10: Nozzle plate 11: Nozzle forming portion00: Printer 01: Liquid discharge unit02: Supply device 02a: Pellet loader 10: Substrate 20: Table 40: Liquid discharge unit41: Head tank 00: Printer

Claims

[CLAIMS]

1. A liquid discharge head comprising: a nozzle plate having a nozzle; a pressure chamber substrate over the nozzle plate, the pressure chamber substrate having a pressure chamber communicating with the nozzle; a piezoelectric element in a portion of the nozzle plate facing the pressure chamber, the piezoelectric element: surrounding the nozzle; and driven to deform the nozzle plate to discharge the liquid in the pressure chamber from the nozzle in a liquid discharge direction; and a heater in the portion of the nozzle plate facing the pressure chamber, the heater surrounding the nozzle to heat the liquid in the pressure chamber.

2. The liquid discharge head according to claim 1, wherein the heater is closer to the pressure chamber than the piezoelectric element in the liquid discharge direction in the nozzle plate.

3. The liquid discharge head according to claim 1, wherein the piezoelectric element is closer to the pressure chamber than the heater in the liquid discharge direction in the nozzle plate.

4. The liquid discharge head according to any one of claims 1 to 3, wherein the heater has a heat generating portion made of molybdenum or platinum.

5. The liquid discharge head according to any one of claims 1 to 4, further comprising: a temperature sensor in the portion of the nozzle plate facing the pressure chamber, and the temperature sensor surrounding the nozzle to detect a temperature of the liquid in the pressure chamber.

6. The liquid discharge head according to claim 5, wherein the heater has a heat generating portion, the temperature sensor and the heat generating portion are disposed in the same layer of the nozzle plate in the liquid discharge direction, and the temperature sensor and the heat generating portion are made of platinum.

7. The liquid discharge head according to any one of claims 1 to 6, wherein the piezoelectric element includes: aluminum nitride; oraluminum nitride including at least one of scandium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, or boron.

8. The liquid discharge head according to any one of claims 1 to 7, wherein the heater has a heat generating area equal to a maximum cross-sectional area, of the piezoelectric element, in a plane orthogonal to the liquid discharge direction.

9. The liquid discharge head according to any one of claims 1 to 8, further comprising: a supply chamber substrate having a supply chamber communicating with the pressure chamber; and another heater on a wall of the supply chamber substrate.

10. The liquid discharge head according to any one of claims 1 to 9, wherein the piezoelectric element is driven to deform the nozzle plate to discharge molten metal as the liquid in the pressure chamber from the nozzle in the liquid discharge direction.

11. A liquid discharge apparatus comprising: the liquid discharge head according to any one of claims 1 to 10, to discharge a liquid onto a medium; and a carriage mounting the liquid discharge head to move the liquid discharge head relative to the medium.

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